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Date of Issue: January 16, 2006

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Contents:
Topics- What’s New in the World of Superconductivity (November)
Feature Articles : Advances in Superconducting Digital Devices- Applications Expanding for Superconducting Digital Devices- Current State of SFQ Packet Switch Circuits/Packaging Technology- Advances in Ultrahigh-Speed HTS Sampler Technology; Success in SFQ Pulse Observation
Using an On-Chip Sampler- Advances in Analog/Digital Converters- Prospects for Post-CMOS Technology
Feature Articles : Advances in Superconducting Power/Industrial Equipment- SMES Deployment- Development of Superconducting Power Cables- Development Status of Superconducting Fault Current Limiters (SFCL)- Current Status of Superconducting Transformers- Superconducting High-Gradient Magnetic Separation for Purification of Wastewater from Paper
Factory- Patent Information- Standardization Activities

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This work was subsidized by the Japan Keirin Association using
promotion funds from the KEIRIN RACE

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What’s New in the World of Superconductivity (November)
Power
American Superconductor Corporation (November 9, 2005)
American Superconductor Corporation (AMSC) has reported their financial results for their fiscal
second quarter ending September 30, 2005. Revenues increased by 14% to US $10.9 million, comparedwith $9.5 million for the same period in the previous fiscal year. The net loss was $6.8 million, comparedwith $4.1 million for the same period in the previous fiscal year. AMSC ended the quarter with cash, cash
equivalents, and short- and long-term investments of $74.5 million and no long-term debt. The company
received $5.2 million in new orders and contracts during the second quarter, bringing its total backlog oforders and contracts to $18.4 million. AMSC updated its revenue visibility for fiscal 2006 to approximately$46 million. "Taking into account the orders and contracts that we anticipate closing this quarter, in addition
to our current revenue visibility, we are now targeting $55 to $60 million in revenues for fiscal 2006," said
Greg Yurek, president and CEO of AMSC.
AMSC expects to complete a "substantial number of additional orders" for power electronic systems
in their fiscal third and fourth quarters. The status of these orders should be confirmed by the end of thecalendar year. Two new contracts from the U.S. Navy for ship propulsion motors and generators are also
expected during the fiscal fourth quarter. Furthermore, two new superconductor projects are anticipated to
begin next year; as part of the "Power Delivery Research Initiative" (PDRI), the DOE plans to develop acontrollable, alternating current cable system and a direct current cable system. These new projects are
expected to provide a substantial revenue opportunity for AMSC.
Source:"American Superconductor Reports Fiscal 2006 Second Quarter and Six-Month Results"
American Superconductor Corporation press release (November 9, 2005)
http://phx.corporate-ir.net/phoenix.zhtml?c=86422&p=irol-newsArticle_Print&ID=780720&highlight
American Superconductor Corporation (November 14, 2005)
AMSC has announced an order for a 40 MVAR Dynamic VAR Compensator (DVC™) to be installed
in an Icelandic power transmission grid operated by Landsnet, an independent power transmission
company. DVC systems are large-scale, transmission-level reactive power solutions built on AMSC's
patented D-VAR platform. The DVC system will be installed in a substation located near a new aluminum
plant that will add an electrical load of approximately 540 MW to the power grid. The DVC will provide
dynamic voltage control and regulation, and will support overall power network stability. AMSC expects toship the system in the summer of 2006 for installation and commissioning in the autumn of 2006. Terry
Winter, AMSC's executive vice president and chief operating officer, commented, "The Landsnet installation
is an excellent example of how critical dynamic voltage regulation is in ensuring reliable and efficienttransmission of electricity for both industry and consumers.”
Source:“American Superconductor Receives Order for Dynamic VAR Compensator (DVC(TM)) System from Grid
Operator in Iceland”“American Superconductor Reports Fiscal 2006 Second Quarter and Six-Month Results”
American Superconductor Corporation press releases (November 9 and 14, 2005)
http://phx.corporate-ir.net/phoenix.zhtml?c=86422&p=irol-newsArticle_Print&ID=782182&highlight
http://phx.corporate-ir.net/phoenix.zhtml?c=86422&p=irol-newsArticle_Print&ID=780720&highlight

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American Superconductor Corporation (November 16, 2005)
AMSC has finalized a contract amendment with the U.S. Department of Energy (DOE) regarding theLong Island Power Authority (LIPA) cable project. Under the terms of the amendment, the DOE will
increase its share of the total approved budget (US $46.9 million) by $8.3 million. This additional sum will be
added to AMSC’s backlog in fiscal third quarter 2006. AMSC plans to ship the final 89,600 meters of HTS
wire required by the project to the cable manufacturer, Nexans, during the present fiscal quarter. The cable
is on schedule for installation in the LIPA grid and is expected to become operational in September 2006.
Source:“American Superconductor Awarded Contract Amendment by Department of Energy for Long Island Power
Authority Cable Project”
American Superconductor Corporation press release (November 16, 2005)
http://phx.corporate-ir.net/phoenix.zhtml?c=86422&p=irol-newsArticle_Print&ID=783511&highlight
Nexans (November 16, 2005)
Nexans will lead a consortium of Forschungszentrum Karlsruhe, the University of Hanover, EnBW
Energie Baden-Württemberg AG and RWE Energy to develop an HTS fault current limiter (SCFCL) for use
in 100-kV networks. The project will initially focus on the development of a single-phase SCFCL module forlaboratory tests. Two three-phase prototypes will then be constructed for network trials by EnBW Energie
Baden-Württemberg AG and RWE Energy. The SCFCL will utilize BSCCO 2212 superconductors
manufactured by Nexans SuperConductors GmbH (a Nexans company based in Germany). The SCFCL
will be based on the principle of “magnetic field triggering” developed in the previous CURL 10 FCL project.
This design concept is expected to result in an economic breakthrough that may help to advance theapplication of superconducting FCLs by minimizing material requirements and reducing cooling costs.
Source:“Nexans leads co-operative project to develop 110 kV superconducting fault current limiters ”
Nexans press release (November 16, 2005)
http://www.nexans.com/internet/Content.nx?contentId=7175
American Superconductor Corporation (November 21, 2005)
AMSC has signed an agreement with the Korea Electrotechnology Research Institute (KERI) to
become an international collaborator in Korea's Development of Advanced Power Systems by Applied
Superconductivity technologies (DAPAS) program. AMSC will become the sole supplier of the 14 km offirst-generation HTS wire required by the project. The company expects to ship the wire before the end of
calendar 2005. AMSC will also provide technical assistance in the areas of cryogenics and transmission
system engineering. LS Cable, a Korean cable manufacturer, will fabricate the 70-meter cold dielectric22.9-kV, 1.26-kA cable, which will be installed in a live transmission grid. LS Cable will also produce thecryogenics system and the terminations.
Source:“Korean Cable Demonstration Project Selects American Superconductor as Sole Supplier of High
Temperature Superconductor Wire”
American Superconductor Corporation press release (November 21, 2005)
http://phx.corporate-ir.net/phoenix.zhtml?c=86422&p=irol-newsArticle_Print&ID=784925&highlight
American Superconductor Corporation (November 29, 2005)
AMSC has received a follow-on order for PowerModule-based wind turbine generator control
systems from Windtec Systemtechnik GmbH, an Austrian supplier of large wind turbine components andWinter, 2006

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system technology. The PowerModule PM1000 power converters will be incorporated into 23 wind turbine
generators, each rated at 1.5 MW, that Windtec plans to ship to China and Japan in calendar 2006.
Source:“American Superconductor Receives Follow-on Order from Austrian Wind Turbine Supplier, Windtec, forWind Turbine Generator Control Systems”
American Superconductor Corporation press release (November 29, 2005)
http://phx.corporate-ir.net/phoenix.zhtml?c=86422&p=irol-newsArticle_Print&ID=790689&highlight

MRI
Siemens Medical Solutions and Invivo Corporation (November 3, 2005)
Siemens Medical Solutions and Invivo Corporation have announced a strategic partnership to
integrate Invivo’s computer-aided-detection (DynaCAD) system with Siemens’ MAGNETOM MRI systems
for advanced breast MRI technology. The new systems will provide radiologists with more detailed
information and streamline workflows through managing large volumes of images. Thomas Tynes, a
director at Invivo Corporation, stated, “The addition of DynaCAD to the existing line of Siemens-certified
Invivo breast MRI coils and biopsy systems provides a comprehensive, fully-integrated approach to breast
MRI diagnostics and intervention.”
Source:“Siemens and Invivo Partner to offer Computer-Aided-Detection System for MRI”
Siemens press release (November 3, 2005)
http://www.medical.siemens.com/webapp/wcs/stores/servlet/PressReleaseView?langId=-1&storeId=10001&catalogId=-1&catTree=100005,13839&pageId=68590
Intermagnetics General Corporation press release (November 3, 2005)
http://www.igc.com/news_events/news_story.asp?id=173

Communication
Superconductor Technologies Inc. (November 2, 2005)
Superconductor Technologies Inc. (STI) has announced their fiscal results for their third quarter,
ending October 1, 2005. Net revenues decreased by 46% to US $3.9 million, compared with $7.3 million forthe same period in the previous fiscal year. Net commercial product revenues decreased by 50% to $3.1
million, compared with $6.1 million for the same period in the previous fiscal year. Government and othercontract revenue totaled $865,000, compared with $1.2 million for the same period in the previous fiscal
year. An ongoing focus on streamlining operations resulted in a reduction in the company’s net loss, from
$5.2 million for the same period in the previous fiscal year to $3.6 million in the presently reported fiscal
quarter. As of the end of the third quarter, STI had a commercial product backlog of $950,000, withremaining minimum purchase commitments totaling $1.5 million under a general purchase agreement fromone customer. During the third quarter, STI received net proceeds of 11.5 million dollars. The company has$18.8 million in working capital, including $14.9 million in cash and cash equivalents.
For the first nine months of 2005, total net revenues were $16.8 million, compared to $19.1 million for
the first nine months of 2004. Net commercial product revenues for the first nine months of 2005 wereWinter, 2006

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Tel: +81-3-3431-4002, Fax: +81-3-3431-4044$14.4 million, compared to $13.8 million in the year ago period. STI recorded $2.4 million in governmentand other contract revenues for the first nine months of 2005, compared to $5.2 million for the first ninemonths of 2004. The net loss for the first nine months of 2005 was $11.2 million, compared to $19.9 million
for the prior year’s first nine months, which included restructuring expenses of $2.7 million, a non cash
interest charge of $802,000 for warrants issued in connection with a bridge loan, and ISCO related litigation
expenses of $438,000.
Source:“Superconductor Technologies Inc. Announces Third Quarter 2005 Results”
Superconductor Technologies Inc. (November 2, 2005)
http://phx.corporate-ir.net/staging/phoenix.zhtml?c=70847&p=irol-newsArticle&ID=777426&highlight
ISCO International (November 3, 2005)
ISCO International (ISCO) has provided a financial update on its operations. ISCO’s visualized
revenue for their fourth quarter, based on shipped orders and orders expected to ship during the quarter,
totaled US $0.6 million as of the end of October. This revenue is equivalent to the revenue for the entire
fourth quarter of the previous fiscal year. John Thode, CEO of ISCO, commented, "While we didn't get off to
as quick a start in Q4 as we would have liked, we are ahead of our Q3 pace and have visibility to a numberof near-term opportunities. Having significantly improved the cycle time and efficiencies of our supply chain,
we will also be prepared to fulfill orders we receive late in the year, a phenomenon we often see in ourbusiness as operators complete their budget cycle." The company recently completed an extensive
commercial trial with a new customer, with excellent results. This success may lead to significant
deployment over the next year.
Source:“ISCO INTERNATIONAL PROVIDES FINANCIAL UPDATE FOR THE FOURTH QUARTER 2005 AND
INVESTOR CALL INFORMATION”
ISCO International press release (November 3, 2005)
http://www.iscointl.com/(Akihiko Tsutai, Director, International Affairs Department, ISTEC)(Published in a Japanese version in the January 2006 issue of Superconductivity Web 21)

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Feature Articles : Advances in Superconducting Digital Devices- Applications Expanding for Superconducting Digital Devices Superconducting digital devices have a long history, dating back to research and development onlatching circuits typified by the so-called Josephson Computer in the 1970s and 1980s. Latching circuits arelevel logic circuits that use Josephson junctions (JJs) as active elements, but they represent voltage levels
as either 1 or 0, just as semiconductor circuits do. Since their clock frequency in principle maxes out atseveral GHz, they were not able to surpass silicon CMOS devices that were rapidly advancing in the 1990s.
The idea of logic devices using the magnetic-flux quantization characteristic of superconductivity originatedin Japan in the 1970s, but since K. Likharev of the State University of New York announced a gate family
dubbed rapid single-flux-quantum (RSFQ), it has been becoming the mainstream of superconducting digital
device development. Such devices, commonly known as SFQ devices, represent both the state in which
there is a magnetic flux quantum on the superconducting loop, and the state in which there is not, as 1 and
0 respectively. They employ JJs as switches and are characterized by so-called pulse logic in which amagnetic flux quantum propagates over the connected superconducting loop, while at the same time, aquantized voltage pulse signal (mV level) with a width of several ps travels through a superconducting wire.
Owing to use of lossless superconducting wiring in addition to such characteristics as a small signal
amplitude, high-speed switching, and pulse logic, the SFQ devices are the only ones that are capable ofclock frequencies exceeding 100 GHz at the LSI level. Moreover, since SFQ devices are further
characterized by low power consumption that is two or three orders of magnitude better than that of CMOS
devices, the International Technology Roadmap for Semiconductors (ITRS) is considering them as themost promising new candidate for logic devices that will break through the silicon device limit that has finallycome into view.
The primary applications envisioned for SFQ devices—listed starting from the lowest level of integration(JJs/chips) required—include measuring instruments, such as samplers and digital SQUIDs (20 to 100 JJs),
analog-to-digital (A/D) converters for measuring or wireless communications (500 to 104 JJs), digital signal
processors for radio astronomy and particle beam/nuclear physics measurements (105 to 106 JJs), switches
for high-end network routers (105 to 106 JJs), and processors for servers and supercomputers (106-107 JJ).
In Japan, which launched fundamental technology development for SFQ devices around 1997 or 1998 as anational project, circuit operation on the scale of about 10,000 JJs on low-temperature Nb circuits, and on
the scale of 200 JJs even on high-temperature YBCO circuits made of complex materials, is becoming
possible thanks to advances in process and design technologies. Thus the nation has reached atechnology level that leads the rest of the world. At present, development is underway with an eye on
demonstrating performance at the component level for medium-to-large-scale equipment, such as networkrouters, servers and A/D converters when using Nb circuits, and for small-to- medium-sized equipment,such as samplers that use small cryocoolers and A/D converter circuits when using oxide circuits.
Connection with semiconductor devices and equipment operating at different environment temperaturesand signal levels is essential to putting equipment and systems that use SFQ devices into practical use, andefforts are being particularly focused on developing a high-speed interface technology between several
GHz and 100 GHz.
(Keiichi Tanabe, Director, Division of Electronic Devices, SRL/ISTEC)(Published in a Japanese version in the October 2005 issue of Superconductivity Web 21)
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Feature Articles: Advances in Superconducting Digital Devices- Current State of SFQ Packet Switch Circuits/Packaging Technology SFQ digital circuits are known for their high speed and low power
consumption characteristics. Packet switch of future high-end router isconsidered as one of suitable applications for SFQ digital circuits.
Packet switch is a kind of random logic circuits, so we have developed
both fabrication technology and design methodology (EDA tools, cell
library, and wiring). By using these developed technologies, a packet
switch circuit and a switch scheduler circuit were designed andfabricated. Both circuits worked at 40GHz clock frequency. Figure 1
shows a photo of a packet switch chip. For realizing an SFQ
subsystem, development of packaging technology is essential. As afirst step, we have developed a 32-channel cryocooler system. Eachchannel speed is 10Gbps. Figure 2 shows a block diagram of thesystem. It consists of multi-chip module, high-speed multi-pin probe,
cryogenic semiconductor amplifier, interconnection cables between
room-temperature and low-temperature. We are now integrating wholeelements, in which an attractive demonstration can be expected.

Fig. 1 Photo of 4x4 switch chipwith a clock speed of 40 GHz.

Fig. 2 Cryocooler system under development(Shinichi Yorozu, Low Temperature Superconducting Device Laboratory, Division of Electronic Devices, SRL/ISTEC)(Published in a Japanese version in the October 2005 issue of Superconductivity Web 21)
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Feature Articles : Advances in Superconducting Digital Devices- Advances in Ultrahigh-Speed HTS Sampler Technology; Success in
SFQ Pulse Observation Using an On-Chip Sampler The speed of measurement systems is being increased in order to develop high-speed devices andnetwork systems. In April 2005, the commercialization of a 100 GHz-band sampling oscilloscope using
semiconductor technology was announced. Even faster systems and electric current measurement
systems using superconducting technology are expected.
Following S. M. Faris’s proposal on the research and developmentof superconducting samplers at IBM in 1980, commercialization using
LTS technology with He gas cooling was carried out at Hypres. Later,
M. Hidaka of NEC conducted research and development on an HTS
sampler using a cryocooler in an effort to produce a more practicalsystem1). Taking over his work, Superconductivity ResearchLaboratory has made research and development on asuperconducting sampler that exceeded 100 GHz as part of its Low
Power Consumption Superconducting Network Device Development
Project starting in 2003. Following the observation of a 45-GHz
waveform by the electric current input method reported in 20042) that
surpassed the previous maximum frequency of 20 GHz, theSuperconductivity Research Laboratory also succeeded in observing a
50 GHz waveform with the voltage input method using the
Fig. 1 High-frequency module
high-frequency module (Figure 1) of the superconducting sampler
developed in cooperation with Advantest Laboratories3). However, in the previously obtained results, thesignal loss of coaxial cable, modules, and other items, and also jitter in the measurement system has madeit difficult to assess whether superconducting sampler chips are really operating at a high speed.
On-chip samplers that employ two single-flux quantum(SFQ) pulse generators as sampling pulse and signal
pulse were prepared as one method to evaluate thehigh-speed performance of the chip itself. Then on-chipsampler circuits that measured SFQ pulses using thesame SFQ pulses were designed and fabricated(Figure 2). The waveform observation of SFQ pulses
with the HTS sampler was firstly succeeded by using a
cryocooler to cool the chip to 40 K and then (Figure 3).
The SFQ pulse width observed this time was about 10
ps. Based on this result, it was estimated that 100 GHz
would be possible for the bandwidth of the chip itself,even using the current process technology (typicaljunction parameter IcRn = 0.7mV).

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In addition, it is becoming clear that the jitter andthermal noise in the sampling pulse has an effecton the bandwidth of a sample from simulated
results4). The performance can be increased by
improving process uniformity, reproducibility, andmeasurement system to counteract such effects.
Furthermore, the basic operation of asuperconducting sampler using a cooled
high-speed photodiode in the signal input section
has been succeeded recently, which means abandwidth of 100 GHz should be possible in thenear future.

Fig. 3 Observed waveform of SFQ pulse

References
1) M. Hidaka, M. Maruyama, and T. Satoh: IEICE (the Institute of Electronics, Information andCommunication Engineers) Trans., Nov. 2003, pp. 1128-1135.
2) H. Suzuki: Superconductivity Web 21, Winter, 2005, p. 16.
3) H. Suzuki et al. Physica C 426-431, p.1643, 20054) M. Maruyama et. al., ISS2005 (Proceedings of ISS2005 to be published as a special issue of Physica C,2006).
(Hideo Suzuki, Division of Electronic Devices, SRL/ISTEC)(Published in a Japanese version in the October 2005 issue of Superconductivity Web 21)

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Feature Articles: Advances in Superconducting Digital Devices- Advances in Analog/Digital Converters Akira Fujimaki, Professor
Graduate School of Engineering
Nagoya University
Ever since it was proposed that analog-to-digital converters (ADCs) using superconducting flux quantum(SFQ) circuits could be applied to software-defined-radio receivers, which are the next generation of radio
communication technology, oversampling ADCs have been the mainstream of development. SFQ-ADCs
can achieve a high precision not possible by other means, because they are capable of accurate negative
feedback with a flux quantum unit and of high-speed operation of several tens of GHz. Although a digital RF
receiver, which directly converts multiple radio signals simultaneously into digital values and then carries out
demodulation and channel selection numerically, is known to be an ideal-like radio receiver having highflexibility, the speed and precision of an SFQ-ADC are necessary to satisfy the demand for the ADC thatwould be used there. In addition, the demand has been growing lately for an increased number ofsuperconducting tunnel junctions (STJs) in a detecting system for x-rays and terahertz-waves. The idea ofusing SFQ-ADCs and SFQ-multiplexers in the multiplexing of output from each STJ also has been
proposed, and the quick development of SFQ-ADCs is demanded strongly from the standpoint of thedetecting system.
An oversampling ADC comprises a modulator on the first part and a decimation filter on the last part. The
modulator must operate at an ultra fast speed, which makes the SFQ technology essential. Moreover, thedecimation filter is a high-speed digital integrated circuit. This part can be implemented either using an SFQ
circuit or using a semiconductor circuit after parallelizing the data and reducing the speed, each of whichalternative has advantages and disadvantages. However, the former implementation, which enables SFQ
circuits to have a variety of functions through digital signal processing, is thought to be beneficial when
considering SFQ-ADCs made of Nb junctions. That is why we went forward with the development of ADC
toward a multiple STJ detectors system. In addition, this was positioned as the first state of the developmentof a digital RF receiver. The photo shows the SFQ-ADC manufactured using Nb/AlOx/Nb junctions (NECstandard process). It has 807 junctions, and both the modulator and decimation filter are operated at a clock
speed of 14 GHz by the built-in oscillator. In addition to employing magnetic coupling input to deliver highsensitivity, this ADC contains two quantizers to reduce external noise and improve the signal-to-noise ratio(SNR). Although the actually measured SNR is 7.5 bits in the 20 MHz band width, we know that the target
value of 14 bits is possible after improving the decimation filter. Meanwhile, Hypres in the U.S. has alreadybeen getting measurements of
11.8 bits and has even succeeded
in developing an ADC comprising
12,000 junctions in an effort toproduce a digital RF receiver. We
believe that there will be a strong
demand for various performanceenhancements for ADCs and for
Photomicrograph of ADC manufactured on a trial basis
their actual use in systems.
(Published in a Japanese version in the October 2005 issue of Superconductivity Web 21)

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Feature Articles : Advances in Superconducting Digital Devices- Prospects for Post-CMOS Technology Nobuyuki Yoshikawa, Professor
Graduate School of Engineering,
Yokohama National University
Even CMOS technology, which has attained dramatic performance improvements through diminishingdevice dimensions, is now facing many difficulties. The main reason for this is that power consumption can
not be further reduced due to the growing leak current that is making it difficult to lower threshold values andreduce gate oxide film. The increasing wiring delay that accounts for circuit operation time also invites
worsening circuit performance. According the ITRS’s roadmap, performance increases from CMOS
technology can be expected up to the 22-nm generation planned for development in 2016. However, thatwill require the development of a variety of new technologies, such as strain silicon technology, insulator
technology for high-dielectric gate, SOI technology, and technology for constructing 3D MOS. Furthermore,this is not a matter of simply developing a single technology but, rather, the performance in the roadmap will
only be achieved by the gradual deployment of all the aforementioned technologies. Consequently, thedevelopment of CMOS technologies will require ever-increasing efforts and investments.
Meanwhile, the roadmap introduces a number of new logic device technologies (Table 1) as candidates
for post-CMOS technologies. Except for superconducting flux quantum (SFQ) circuits and resonant tunnel
devices, high-speed operation at the logic circuit level has not been proven for these new technologies andthey have many unknowns. SFQ circuits, for which integrated circuit operation on the scale of 10,000
junctions has already been proven, can be called the most promising candidate for post-CMOS technology.
Table 1 New logic device technologies and their performance (Source: ITRS roadmap)

SFQ devices
One-dimensional FET devices
Resonant tunnel devices
Single-electron devices
Molecular devices
Quantum cell automatons
Spin devices

Dimensions
300 nm
100 nm
100 nm40nm
unknown
60 nm
100 nmCircuit Speed
250–800 GHz
30 GHz30 GHz
1 GHz
1 MHz
1 MHz
30 GHzOperation Energy
2 x 10-19 J
2 x 10-18 J> 2 x 10-18 J
1 x 10-18 J
1 x 10-16 J
1 x 10-18 J
2 x 10-18 J

SFQ circuits are logic circuits that use single-flux quantum, a minute physical quantity, as an information
carrier, and they operate at extremely high speed with low power consumption. Their operating speed
improves in proportion to the dimensions of their Josephson junctions, but the maximum value is ultimately
limited by the superconducting energy gap. Table 2 shows the performance limit on SFQ circuits when Nb
is used. A clock frequency some 10 times better than the performance limit of 22 nm CMOS (16 GHz, 3Gtransitors/cm2) can be expected with SFQ circuits. The low integration density can be compensated bythree-dimensional integration. In addition, by using oxide-based superconducting materials, clock
frequencies reaching tera hertz are possible. Furthermore, with SFQ circuits, light-speed ballistic conductionof the SFQ pulses that make use of superconducting transmission lines is possible, as is inter-gate

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Tel: +81-3-3431-4002, Fax: +81-3-3431-4044

communication that is not limited by wiring delay. That is why SFQ circuits can build high-performance
information processing systems that would be impossible to create with CMOS circuits.
Table 2 Limit of SFQ circuit performance(When Nb material is used. Large-scale system, such as a microprocessor, is envisioned.)

Junction size
Critical current density
Clock frequency
Power consumption
Integration density

Currently, development of SFQ
microprocessors is underway at
Nagoya University and Yokohama
National University with an eye on
realizing the high-performanceservers of the future. Figure 1
shows the progress that has been
made in SFQ microprocessor
performance.
Since
the
microprocessor that has beendeveloped has few commands
and a shorter word length than
CMOS, a direct comparison withCMOS would be impossible, but
the latest design achieves 1
GOPS compared with a CMOS
microprocessor, and performance
evaluations by means of tests are
now underway. With the use ofminiaturization and multilayering,
proven performance exceeding
CMOS is just around the corner.

0.3 µm100 kA/cm2
125 GHz–250 GHz
25 nW/gate–50 nW/gate
Up to 100 M junctions/cm2

Fig. 1 Improving the performance of SFQ microprocessors.
Operation has been proven for CORE1α. Design of CORE1β
has been complete, and testing of operation performance isunderway.

(Published in a Japanese version in the October 2005 issue of Superconductivity Web 21)

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Date of Issue: January 16, 2006

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Tel: +81-3-3431-4002, Fax: +81-3-3431-4044

Feature Articles: Advances in Superconducting Power/Industrial Equipment- SMES Deployment Shigeo Nagaya
LeaderSuperconductivity and New Material TeamElectric Power Research and Development Center
Chubu Electric Power Co., Ltd.
Since superconducting technology in the field of electric power is characterized by the ability to efficiently
handle large currents, it has wide-ranging upstream to downstream applications, including power
generation, power transmission/transforming, and storage. It is expected to be one of the technologies
underpinning electric power in the future, thanks to is broad applicability, high efficiency, and ability toconserve energy.
In addition, attention is being focused on the application of superconducting technology to issues relating
to the quality of power that comes with price competition, and the introduction of distributed power sourcesin recent years, and there are high hopes for the practical use of superconducting magnetic energy storage(SMES).
SMES stows electric power as a magnetic field in a superconducting coil, and it is characterized by theability to instantaneously release the power it is storing, the ability of the storage section to be freely
configured by only the amount of energy necessary, and superconducting coils (the storage section andheart of SMES) that can handle repeated charging.
Based on its ability to instantaneously release a vast amount of power, the application of SMES to thefield of electric power is being studied for stabilizing power networks and performing load compensation forvoltage transforming in steel making and railways, which have a lot of repeated charging. However,progress is also being made toward its introduction into instantaneous voltage drop compensators, thanks
to its ability to freely configure the storage section based only on the required amount of energy.
An instantaneous voltage drop is a phenomenon in which voltage lowers for about a second due to alightning strike on a transmission line or some other cause. At the semiconductor and LCD plants with thelatest equipment, such drops in voltage impacts plant operations and causes major damage.
One means of preventing this is to install an uninterruptible power supply (UPS) that uses batteries oranother power source. A UPS will provide backup power during the voltage drop, but since instantaneous
power drops are for the most part about 0.3 second long, the UPS must output a massive amount of power.
The total amount of energy in order to compensate for the drop in voltage is output multiplied by time, whichmeans adequate performance can be delivered up to about several kilowatt hours.
SMES displays characteristics exactly in this regard, as opposed to other power storage devices, and it isable to instantaneously release stored energy and store only the amount of energy need for the operatingtime. Among the various power storage technologies out there, double layer capacitors also exhibit suchcharacteristics, but since they are capacitors, they have limits in terms of output, so when talking about
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output between several thousand kVA and 10,000 kVA, as is required by large scale plants, SMES is the
optimal system in terms of specifications and performance.
At present, we are just beginning to test a 10,000 kVA system at Sharp Corporation’s Kameyama Plant,
following an actual field test there on SMES for compensating an instantaneous power drop of 5,000 kVA.
SMES has performed beyond our expectations for instantaneous power drops that have occurred thus far,and its outlook from a technical standpoint is good.
The practical application of superconducting technologies and equipment in addition to SMES obviously
requires that their costs, in respect to their functionality and capacity, be deemed appropriate from the user’s
perspective, or in other words, the switch to superconducting must be profitable. In that respect, reducing
the cost is believed to key to the practical application of superconducting technologies.
In addition, the reliability of superconducting equipment in the latest SMES demonstration test was
actually in the cooling technology for superconducting, rather than the superconducting section itself. Whensuperconducting technology is introduced in electric power and other infrastructures, the reliability of thiscooling technology will be decisive.
Under the present circumstances, the cooling technology is an issue, and maintenance beyond what was
imagined is required. However, innovative technical development for the reliability of this cooling technology
is underway in the national project for SMES development, and when the project ends in 2007,
epoch-making cooling technology will be in ours.
We hope that such reliability will be secured that we can reach a level where users are not even awarethat superconducting is in use, and we would like to aim for practical applications at the earliest possible
time.

(Published in a Japanese version in the November 2005 issue of Superconductivity Web 21)

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Date of Issue: January 16, 2006

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Tel: +81-3-3431-4002, Fax: +81-3-3431-4044

Feature Articles: Advances in Superconducting Power/Industrial Equipment- Development of Superconducting Power Cables Ken-ichi Sato
Electric Power & Energy Research Lab.
Sumitomo Electric Industries, Ltd.
1. Advances in mass production and increased performance of high-temperature superconducting wire
The application of pressurized sintering has increased yields of bismuth-based high-temperature
superconducting wire and improved its mechanical and electrical characteristics by a factor of 1.5. This
enables the mass production of 1,600-m-long wires and critical current at 77 K of between 150 and 170 A(4-mm width). The applicability is widening to 200,000 Am at Ic x L (critical current x length) and to 500,000
Am at 1-cm width conversion. This is an improvement of even physical characteristics, such as Birr
(irreversibility field) and Young's modulus, over conventional bismuth-based high-temperature
superconducting wire, resulting in the emergence of a very different kind of superconducting wire.
Results of technological developments exceeding 100 m and 100 A (1-cm width), even with thin-film wirematerials using YBCO and HoBCO, have been announced by five organizations worldwide (Sumitomo
Electric Industries, SRL, Fujikura, SP, and AMSC), and they are attempting the challenge ofcommercializing such thin-film wire material.
2. Features and current state of high-temperature superconducting cables
There are increasing hopes for superconducting cables that will enable the transport of vast amounts ofelectric power with less energy and space by lowering cooling costs through the use of liquid nitrogen (77 K)
as a cryogen. Specifically, according to the Energy Policy Act of 2005—established in August 2005 in the
U.S., where the modernization of power networks has become a national issue—high-temperature
superconducting cables are expected to be the trump card for solving power network problems.
High-temperature superconducting cables enable a capacity increase of two or three times by replacing
existing cables when raising capacity on existing underground infrastructure, and even on newly build lines,
distances are shorter and infrastructure lighter compared with overhead transmission lines, andenvironmentally friendly lines that are EMI-free, cost less, and conserve energy can be built. Since
high-current transmission lines result, they have lower voltages than conventional lines and infrastructure islighter, making it possible to inexpensively build transmission lines about which residents need not worry.
Another feature of superconducting cables are their potential as new solutions to the increasing electricenergy of the future, including the lowering of construction costs and conversion of high-voltage substations
to low-voltage substations and low-voltage switching stations, through the conversion of conventional
high-voltage transmission networks to super-conducting (low voltage) transmission networks. The use of
liquid nitrogen as a cryogen also provides protection against explosions and fire, and delivers temperature
uniformity (low heat cycle).
In addition, DC superconducting cables are an area in which major technical advances are expected.
With present technology, DC power transmission exceeding 10,000 A is possible, and this enables thetransmission of the same amount of power with a required cross section only several tenths that of copper
AC cable. This reduces transmission loss to about one-eightieth. Hopes are high for such things asinterconnections with high-capacity distributed power sources (for example, solar power generation andWinter, 2006

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wind power generation) as well as applications to DC power supply to Internet data centers where powerloads concentrate, high capacity trunk lines, and interconnected power system lines.
Verification tests on the practicality of the 3-in-one 100 m, 114 MVA superconducting cable by Tokyo
Electric Power Company (TEPCO), Sumitomo Electric Industries, and the Central Research Institute ofElectric Power Industry (CRIEPI) were successfully concluded in 2002, and demonstrations ofhigh-temperature superconducting cables are planned, first in the U.S., Europe, and Japan, and later inSouth Korea, China, and Mexico. In the U.S., demonstrations are underway simultaneously in threelocations (Albany and Long Island in New York, and Columbus in Ohio) under the auspices of the State of
New York and the Department of Energy. Table 1 provides an overview of the various projects.
The results of these projects are expected in 2007, and new developments toward the next step are
anticipated.
Table 1 High-Temperature Superconducting Cable Projects
Project
Name

Members

UtilitySponsorTEPCO

Sumitomo Electric TEPCO
Industries
Copenhage NKTnSouthwire Southwire

DOE

Detroit

DOE

Pirelli

Detroit
EdisonDanishEnergyAuthority

BudgetLine Condition Insulation¥2bilion(US$18M)

AC66kV–
1000A–100m
AC30kV–
2000A–30m
AC12.5kV–
1250A–30m
AC24kV–
2400A–120m
AC77kV–
1000A–500m

METI,NEDO
Super-ACE Super-GM(Furukawa Electric,
CRIEPI)
YunnanInnopower, InnoST, Yunnan Electric Chinese Ministry of 35milionyuan AC35kV–
Shanghai Cable Power
Scienceand (US$4.3M) 2000A–33.5m
Works
Technology, City ofBeijing, and Yunnan
Province
DAPAS
LG cable, KERI, Korea Electric [South] Korean MinistryAC22.9kV–
KIMM
Power
of Science and1250A–75m
Technology
AC10.5kV–
Lanzhou
Chinese Academy
1500A–75m
of Science, (Chang
Tong CableCo.)
KEPRI
KEPRI, Sumitomo Korea Electric South
Korean ¥240milion AC22.9kV–Electric Industries, Powergovernment
1250A–100m
KERI, KBSI andotheruniversities
Niagara
DOE,NYSERDA
US$26milion AC34.5kV–
AlbanySuperPower,
800A–350m
Sumitomo Electric Mohawk
Industries,BOC
LIPA
Ohio

AMSC, Nexans, Long Island DOE
AirLiquide
PowerAuthority
Ultera,ORNL
American
DOE
ElectricPower

US$30milion AC138kV
2400A–660m
US$9milion AC13.2kV
3000A–200m

lowtemperature

Material
Phase
Config-ura Usedtion
3-in-1
Bi2223

Material
SourceTest
PeriodNotes

normaltemperature 1x3

Bi2223

Sumitomo Electric 2001–2002
Industries
NST
2001–2003

lowtemperature

1x3

Bi2223IGC

2000–

ongoing

normaltemperature 1x3

Bi2223AMSC

10.2001–

failedlowtemperature

1x1

Bi2223

-2004–2005

no
heat
cycle

normaltemperature 1x3

Bi2223

InnoST

4.2004–lowtemperature

3-in-1

Bi2223AMSC

5–12.2004

normaltemperature 1x3

Bi2223

AMSC

2005–

lowtemperature

3-in-1

Bi2223

Sumitomo Electric 2005–
Industries

lowtemperature

3-in-1

Bi2223(YBCO*)

Sumitomo Electric 2005–
Industries(SP*)

lowtemperature

1x3

Bi2223

AMSC

2006–

lowtemperature

3-phasecoax

Bi2223

AMSC

2006–

* replaced with
30-m YBCO
cable on latter
half(Published in a Japanese version in the November 2005 issue of Superconductivity Web 21)

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Date of Issue: January 16, 2006

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Superconductivity

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Tel: +81-3-3431-4002, Fax: +81-3-3431-4044

Feature Articles: Advances in Superconducting Power/Industrial Equipment- Development Status of Superconducting Fault Current Limiters (SFCL) Shinji Torii
Electric Power Engineering Research Laboratory
Central Research Institute of Electric Power Industry (CRIEPI)In the Research and Development of Fundamental
Technologies for a Superconducting AC Power Equipment
project, we developed S/N transition-type SFCLs that used
YBCO thin films and a reactor for a rectifier-type SFCL that uses
Bi-2223 wire. Mitsubishi Electric and Toshiba were in charge of
the S/N transition-type SFCLs. Mitsubishi Electric developed a 1
kA-class SFCL for the development of large-current
technologies, while Toshiba developed a 6.6 kV SFCL for thedevelopment of high-voltage technologies.
Mitsubishi Electric developed a structure that aimed touniformly distribute current and reduce AC loss by connecting inparallel and in an octagonal arrangement eight pieces of 3 x 10
cm YBCO thin film on which gold had been deposited (seeFigure 1). Two of these were connected in series, and one hourof continuous current was verified at 1 kA and five minutes at
1.2 kA, and it was also verified that fault current exceeding apeak value of 20 kA when there was no SFCL was limited to
5.22 kA.
Toshiba developed a structure connecting 1 x
12 cm pieces of YBCO thin film at 1-cm
intervals on Ni thin film via indium (see Figure 2).
Forty of these elements were connected inseries, and using a resonant power source, fault
current limiting operation at a peak value of 10.9
kV and about 500 A was verified. Furthermore,
the SFCL constructed with four elements seriesconnection was introduced on to a model
system assumed that the short-circuit capacity
was increased caused by connecting
distributed power supplies to a 6.6 kV
distribution system, and it was verified that it
could withstand operation on the model system
in Power System Simulator in CRIEPI.
Moreover, at High Power Testing Laboratory in
CRIEPI, SFCLs connecting 20, 30, and 40 of
the elements in series were used to verify that

Winter, 2006

Fig. 1

Photo of 1 kA-class
SFCL element

IndiumSilverYBCO
Sapphire
Nickel thin film
Aluminum nitride

Fig. 2

Structure of high-voltage SFCL
element© ISTEC 2006 All rights reserved.

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breakdown voltage per element did not drop due to increase in the number of elements connected in series.
The maximum breakdown voltage in this case was about 14 kVrms with a module connecting 40 of theelements in series.
In addition, Toshiba developed a 66-kV 750-A
pulse magnet (see Figure 3). Tests on its coolingcharacteristics and rated current were conducted.
Worth particular mention are the withstand-voltage
tests that were conducted using a 66-kV power
apparatus conforming to JEC. Between theelectrodes and ground, the test passed at AC 140
kVrms for one minute and at three lightning impulsesof 350 kV at both polarities, while between themagnet electrodes, the test passed at three lightning
impulses of 350 kV at both polarities. A fault
current-limiting test that included in a rectifier circuit
was also conducted.

Fig. 3 Superconducting coil housed in its casing

Overseas, SFCLs using Bi-2212 cylinders manufactured by NEXANS are being developed, and they arebeing applied to the CURL 10 project in Europe and the Matrix Fault Current Limiter project in the U.S.

(Published in a Japanese version in the November 2005 issue of Superconductivity Web 21)

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Tel: +81-3-3431-4002, Fax: +81-3-3431-4044

Feature Articles: Advances in Superconducting Power/Industrial Equipment- Current Status of Superconducting Transformers Masataka Iwakuma, Associate Professor
Research Institute of Superconductor Science and Systems (RISS)
Kyushu University
In our report of the current development status of superconducting transformers, we will reconfirm thesignificance of making transformers superconductive, and then based on this, explain the present state ofdevelopment. The advantages of making transformers superconductive are generally considered to be theirsmall size, light weight, and high efficiency compared with conventional equipment. Some naysayers
complain that there is no reason to invest in developing further efficiency by superconductivity because
existing equipment already exhibits power efficiency exceeding 99%, and small size and light weight are notmuch recognized as a product of increased efficiency. The basic parameter in transformer design is“one-turn voltage.” Normally, the primary and secondary voltage of a transformer is determined bystandards, and if we let B be the saturated magnetic flux of the core, S the cross section, and n the numberof turns in the winding, then voltage V of both the primary and secondary will be given by V = -d(nBS)/dt. In
this equation, B is nearly a constant B = 1.5-1.7T, but cross-section S and number of turns n can be freely
set. Consequently, when switching to superconductivity, the core cross-section S can be decreased and thenumber of turns n increased compared with non-superconducting transformers. This corresponds to a drop
in voltage per turn, and in the world of non-superconducting transformers, this is generally known as
installation using the normal copper conductors. If we could achieve a low-loss state without increasing thephysical size of the winding, even when the number of turns rises, by using the characteristic low loss andhigh current density of superconducting wire, not only would the core be thinner and lighter, but also thewinding would be lighter and compact, enabling a small and lightweight transformer. The majority of heatload at low temperature is AC loss that occurs on the winding, and it can be said that the decision on
making transformers superconducting depends on the reduction of loss in superconducting wire. The
power required for cooling and the weight and dimensions of the cooling system are determined by the sizeof the AC loss. Important here is the fact that the majority of the power required for cooling converts into heatas a cooling penalty. The advantages of superconductivity, i.e. small size, light weight, and increased
efficiency can be realized only after this heat falls below the Joule loss produced by the copper windings ofconventional transformers. Ninety-nine percent efficiency means 1% of transmitted energy is converted toheat. If this could be reduced to one-fifth or one-forth by switching to superconductivity, the cooling system,
too, could be reduced to one-fifth or one-forth. Heat release/cooling equipment accounts for half of thephysical size of transformers, and in the case of underground substations in particular, it is not much known
that the facilities/construction cost for cooling is about equal to or higher than the transformer itself. Even 1%heat release is an immense amount of transmission energy and difficult to cool. Ultimately, if the current lossof superconducting windings decreases, it will be possible to greatly reduce the one-turn voltage, create
installations using normal copper conductors, and house the entire reduced-size core in a cryostat. In thiscase, the cryostat material can be inexpensive steel as in conventional models, instead of GFRP. This is theultimate ideal form of a superconducting transformer.
Research and development is underway in pursuit of this ideal form of superconducting transformer,
primarily in Japan, the U.S., and Europe, but also lately in South Korea and China. What follows is a reportfocused on the latest prototypes from the standpoint that the cutting edge of equipment research anddevelopment is testing that uses prototypes.
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In the U.S., Waukesha Electric Systems,
SuperPower, Energy East, and the ORNL
research group, with assistance from the
DepartmentofEnergy(DOE),
manufacturedathree-phase,
24.9-kV/4.2-kV, 5/10-MVA transformer
between 2003 and 2004 and is currently
testing its characteristics with an eye on
developing a 138-kV/13.8-kV, 30-MVA
model. Just as in the previously described
ideal transformer, the entire core is housed
in a tank. The cooling system uses a
cryocooler in which the natural convectionof He gas cools the winding. The operating
temperature is between 30 K and 77 K.
However, since core loss is rather high at
present, the core is thermally isolated fromthe winding by a liquid nitrogen shield, so
Fig. 1 A 3φ 24.9-kV/4.2-kV, 5/10 MVA prototype transformer
manufactured by WES. The transformer is housed in a steel
that it operates nearly at room temperature.
tank.
However, this first try ended in failure
because dielectric breakdown occurred atvoltages far lower than the rated voltage. This year and last, they removed the winding from the tank to try tofind out why this was happening, but it is not difficult to imagine that the dielectric breakdown is beingcaused by the low dielectric strength of the He gas. They alsocame up with a conceptual design for a separate 30-MVA
transformer, and came to the conclusion that Jc performanceis inadequate and AC loss too high with current Bi-2223 wire.
They have, therefore, announced that they will begin
developing the transformer using Y-based wire.
In Japan, the Fukuoka Industry, Science & Technology
Foundation(Fukuoka
IST)
manufacturedaliquid-nitrogen-cooled, single-phase, 22-kV/6.9-kV, 1 MVA
prototype transformer during a Regional Consortium Projectcommissioned by the New Energy and Industrial Technology
Development Organization (NEDO), and in 2000, Kyushu
Electric Power incorporated it into a subcooled liquid nitrogen
circulation unit at its Imajuku substation and performed thefirst system interconnection test in Japan. The technicaldevelopment of a spot-network-class superconducting
transformer for electric power was concluded successfully. In
the Super-ACE (Research and Development of Fundamental
Technologies for Superconducting AC Power Equipment)
project that followed this, Fuji Electric Systems Co., Ltd.
manufactured a prototype single-phase 66-kV/6.9-kV, 2-MVA
distribution transformer in 2003 and went as far as a factory

Winter, 2006

Fig. 2 A Fuji Electric Systems’ prototype
1φ 66-kV/6.9-kV, 2 MVA transformer© ISTEC 2006 All rights reserved.

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test. The core is kept at room temperature, the winding is housed in a GFRP cryostat, and cooling is
performed using a subcooled liquid nitrogen (66 K) circulation unit that combines a cryocooler and a pump.
Except for a short-circuit test, this prototype soundly passes all other tests, including a 350-kV lightning
impulse withstand voltage test and a 140-kV AC overvoltage test, as per JEC standards, and it was able totechnically demonstrate the possibility of a nitrogen-cooled distribution-class transformer. However,efficiency at a cooling penalty of 10 is 99.5%, an improvement of 0.5% over conventional transformers, but
realizing the previously mentioned ideal form of transformer requires that the AC loss of the wire bedramatically reduced.
In Japan, the Railway Technical Research Institute manufactured a prototype single-phase
25-kV/1.2-kV/0.4kV, 4 MVA transformer and is assessing its characteristics with an eye on reducing theweight of the transformers installed on bullet trains. The core is kept at room temperature, while for cooling,a subcooled liquid nitrogen system using natural convection is being employed by the cryostat. Whilecurrent transformers weigh more than 3 tons, the prototype is only 1.7 tons when the cryostat is excluded.
The design used in this case is an attempt to employ the high current density and low loss ofsuperconducting wire by lowering the previously mentioned one-turn voltage below conventionaltransformers and enabling installation using the normal copper conductors. However, in order to ensure
maintenance-free operation, incorporating a cryostat fit for the AC loss of 6 kW that occurs on the prototype
results in its total weight far exceeding that of current
transformers. In a bid to truly lighten transformers by
reducing the AC loss of superconducting wire, the Railway
Technical Research Institute this year launched a new
four-year project with financial backing from the Ministry ofLand, Infrastructure and Transport.
In Europe, ABB manufactured a prototype three-phase18.7-kV/0.42-kV, 630-kVA transformer and is carrying out along-term system test, while Siemens manufactured a
prototype 1-MVA transformer for railcar use. However,research and development on transformers is currently at astandstill in Europe.
The economic feasibility of switching to superconducting
transformers is seen as being quite low as long as thefocus is on verifying prototypes and a dramatic cut in the
AC loss of the superconducting wire is not achieved, andthis is not limited only to transformers. Even in Japan, there
are new plans for the development of superconducting
equipment that uses Y-based wire, and we expect that the
pursuit of reduced AC loss will begin in earnest, combinedwith an improved Jc characteristic.

Fig. 3 A Railway Technical ResearchInstitute prototype 1φ 25-kV/1.2-kV/0.4kV,
4 MVA transformer for bullet trains(Published in a Japanese version in the November 2005 issue of Superconductivity Web 21)

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Feature Articles: Advances in Superconducting Power/Industrial Equipment- Superconducting High-Gradient Magnetic Separation for Purification ofWastewater from Paper Factory Shigehiro Nishijima, Professor
Shinichi Takeda, AssistantDivision of Sustainable Energy and Environmental Engineering
Graduate School of Engineering, Osaka University
Paper recycling is one of the crucial issues for building a recycling-oriented and sustainable society. We
have developed a small-footprint system that uses a superconducting magnet to quickly and inexpensively
carry out the advanced purification of the vast quantities of water used in processes at recycled-paper
factories. The system we developed attaches small highly magnetic particles to suspended solids andorganic components (for example, dyes, pigments, adhesives, and flocculants) or, conversely, makes thesesubstances attach to the small highly magnetic particles, and then uses a high-gradient magnetic field
generated by a superconducting magnet to perform highly efficient magnetic separation. At present, thesystem is processing 2,000 t/day at recycled-paper factories. The research and development on thissystem was a four-year project launched in 2001. The project was entitled Superconducting High-Gradient
Magnetic Separation for Purification of Wastewater from Paper Factories and was carried out with support
from NEDO’s program for promoting research on fundamental technology (commissioned by Futaba Shoji
Co., Ltd.).
A recycled-paper factory uses a massive amount of water (5,000 tons/day at a medium-sized factory)
and outputs a similar amount of wastewater. Emission standards have been strengthened in recent years(COD < 20 ppm), and the costs of satisfying such standards are mounting, resulting in economic problems
for factories. For example, introducing biological treatment equipment at a 5,000-ton-class factory
necessitates an investment of several hundreds of millions of yen, and using sewers costs about ¥200
million a year. In either case, the cost of water purification is high, and a number for recycled-paper factories
have actually ceased operations. That is why we got involved in developing a wastewater purification
system that uses superconducting high gradient magnetic separation and can be introduced at
recycled-paper factories. We have already completed a 2,000 ton/day system and introduced it at a factory
where tests on its performance are underway.
Figure 1 shows photos and a conceptual diagram of the entire system. This system is installed on thelater stage of ordinary equipment (pressure floatation unit) for the factory’s wastewater. The wastewater
treated by the pressure floatation unit is 200 ppm to several hundred ppm in COD and cannot be released
as is. Our solution was to treat it using our superconducting high-gradient magnetic separation system,
which purifies to a level at which the water can either be reused or released. As is shown in the figure, thefactory’s wastewater is first collected in a magnetic tank, and then wastewater containing flock (magnetic
flock), to which highly magnetic particles are attached, is transferred from the magnetic tank to the settlingtank. Magnetic separation of the magnetic flock is possible, but first the big, heavy flock that settles rapidly isseparated to reduce the load on the magnetic filter installed within the superconducting magnet. The
smaller and relatively lighter flock is then transferred from the settling tank along with the overflow to themagnetic separator, which is comprised of a superconducting magnet. Thin ferromagnetic wires (about 1
mm in diameter) are arranged within the superconducting magnet, and high-gradient magnetic field isformed in its vicinity. The magnetic flock is separated by being attracted to these wires (a magnetic filter) by
the high-gradient magnetic field, and then the water can be reused as recycled water. The magnetic flock,

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separated by the lower part of the settling tank and the magnetic filter, is recovered as magnetic sludge, anda portion of this is reused as a magnetic agent (return sludge).
Results from a 200 ton/day test showed that purification up to a COD range of 38 ppm to 60 ppm waspossible. With system optimization, the post-treatment COD value was lowered and a marked decrease inturbidity achieved, and we were able to confirm that the treated water could be reused.
The initial cost of this system is about ¥100 million. The cost of a 2,000 ton/day system using theconventional activated sludge method is several ¥100 million as previously mentioned. On the other hand,when discharging to the sewer, the annual cost becomes ¥200 million. Clearly, the initial cost of this system
is considerably less than that of systems using the activated sludge method. A study of the system’s runningcost revealed that, including labor outlays, it costs about ¥130 per ton of water purified. On the other hand,the cost of using the sewer and purchasing new industrial water is ¥250 per ton. Based on this, we can saythat the running cost of this system is about half that of the conventional method, and it therefore offers
considerable economic advantages.
Overview of system we developed
Settling tankFeatures

Magnetic tank

1) High-speed processing2) Compact
3) Economical

System block diagram
Magnetic
agent

Sludge treatment

Raw
water
Magnetic
tank

Superconducting
magnetic separation& filter exchangesystemSettling
tank

Waste排水water

Magnetic
separator
Sludgetreatment

Plant unit
Magnetic separator ¥40 million
Magnetic tank
¥ 7 million
Settling tank
¥13 million
Sludge recovery unit ¥10 million
Online units¥10 million
Facilities equipment ¥10 million
Total¥90 million

Top view
6m

High-speed
treatment tankUtility

Magnetictank

Elevation view

6m

7m

Settlingtank

Magnetic
separator

Fig. 1 Superconducting high-gradient magnetic separation system that we manufactured(Published in a Japanese version in the November 2005 issue of Superconductivity Web 21)

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Tel: +81-3-3431-4002, Fax: +81-3-3431-4044

Patent Information

Introduction of Published Unexamined Patents in the First Half of Fiscal 2005
The following are ISTEC’s patents published from April through September 2005. For more information,access the homepage of Japan Patent Office and visit the Industrial Property Digital Library (IPDL).
1) Publication No. 2005-252019: “Superconducting Electronic Devices”
Implementing single flux quantum (SFQ) circuits that operate at ultra-high speed requires that the top
and bottom superconducting layers be separated by insulating interlayer with low dielectric constant andlow dielectric loss. Conventionally, an insulating oxide for the insulating interlayer was selected with aview to ensuring superconducting characteristics in the superconducting layers, resulted in an oxide withhigh dielectric constant. That is why it has not been realized to fully bring out the high-speed potential of
SFQ circuits. This patent achieved an insulating interlayer with low dielectric constant and low dielectricloss as well as high electrical insulating properties by employing a multilayered insulating film composed
primarily of low-dielectric-constant MgO, without degrading the characteristics of the superconducting film.
This reduces the parasitic capacitance of Josephson junctions and superconducting wiring, enabling theprevention of waveform distortion in high-frequency signals and making circuit design easier.
2) Publication No. 2005-252400: “Gate Blocks, Logic Circuits using them, and their Design Method”
This invention relates to the method of configuring signal lines that include the clock signal between logic gate
blocks, and makes it easier to design single flux quantum (SFQ) circuits that operate at ultra-high speed.
With the conventional method, a signal line was branched into plural lines outside gate blocks, but in thisinvention, the branching of a signal line is included in the design of a gate block configuration withconsidering the connection to the next gate blocks, and signal connections between gate blocks are madeusing only passive transmission lines. This invention remarkably reduces the number of receiver gatesand driver gates for signal connection, thereby not only improving the integration density, but also improving
operation speed and lowering power consumption.
3) Publication No. 2005-259812: “Superconducting SFQ Circuits”
This invention provides a superconducting single flux quantum (SFQ) integrated circuit in which a partial
ground-potential fluctuation of some circuit block in the SFQ integrated circuit does not malfunction other circuit
blocks in the SFQ integrated circuit. The SFQ integrated circuit in this invention has plural grounding
electrodes. The integrated circuit is comprised of SFQ circuit bullock No.1 connected to grounding electrodeNo. 1, SFQ circuit block No.2 connected to grounding electrode No.2, and a separating superconducting SFQ
circuit block that connects SFQ circuit blocks No.1 and No. 2. Furthermore, it is characterized by aconnection between grounding electrode No. 1 and No. 2 by means of inductive wiring.

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4) Publication No. 2005-260364: “Superconducting Latching Driver Circuits”
This invention provides superconducting latching driver circuits that are applied with DC bias current andare designed to generate adequate output voltage. Conventionally, AC bias current was applied toJosephson junctions to reset latching driver circuits, but this bias current brought about fluctuations ingrounding potential, which severely limited the operating margin. To latch onto SFQ pulses,
superconducting latching driver circuits from this invention contain a latching circuit comprising Josephson
junctions with hysteresis characteristics, a load circuit comprising load inductance and load resistanceconnected to the output of the latching circuit, as well as a reset circuit between the output of the latchingcircuit and the load circuit, and they are characterized by the biasing of the Josephson junctions in thelatching circuit with DC current. Once the latching circuit latches onto SFQ pulses, the reset circuit will
reset it after a predetermined time.
(Katsuo Nakazato, Director, Research & Development Promotion Division, SRL/ISTEC)(Published in a Japanese version in the November 2005 issue of Superconductivity Web 21)

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Date of Issue: January 16, 2006

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Standardization Activities
Topics in September- IEC/TC90 to Hold Ad Hoc Group Conferences in U.S. and EU The IEC/TC90 will be holding ad hoc group meetings regarding “uncertainty” and “superconducting
current leads” in the U.S. and Europe between August and September 2005.
—Ad hoc group 2 conference—• Rapporteur: Loren F. Goodrich (U.S.)• Date: August 29, 2005 (during the CEC/ICMC 2005: Cryogenic Engineering Conference and International
Cryogenic Materials Conference [CEC/ICMC 2005] session)• Location: Keystone, CO, U.S.
• Topic: Dealing with “Uncertainty” in Superconducting Standards—Ad hoc group 1 conference—• Rapporteur: Kozo Osamura (Kyoto University)• Date: September 14, 2005 (during the 7th European Conference on Applied Superconductivity[EUCAS’05] session)• Location: Vienna, Austria• Topic: International Standardization of “Designs for Superconducting Current Leads and General
Requirements for Characteristic Tests”—Ad hoc group 1 conference—• Rapporteur: Kozo Osamura (Kyoto University)• Date: September 21, 2005 (during the 19th International Conference on Magnet Technology [MT-19]
session)• Location: Genoa, Italy• Topic: Continued Discussion of International Standardization of “Designs for Superconducting Current
Leads and General Requirements for Characteristic Tests”(Published in a Japanese version in the September 2005 issue of Superconductivity Web 21)

Topics in November- Second and Third Ad Hoc Group 1 (Current Leads) Conferences to Be Held Ad hoc group 1 of the IEC/TC90 (superconductivity) held the second and third ad hoc group conferences(Rapporteur: Kozo Osamura, Kyoto University) on September 15 and 21, 2005 in Vienna and Genoa,
respectively. The conferences were held jointly with EUCAS’05 and MT-19, respectively. The first
conference had been held in October 2004 in Florida, U.S.

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Kozo Osamura (Professor, Kyoto University), Takakazu Shintomi (Professor, Nihon University), and
Ken-ichi Sato (Secretary, Sumitomo Electric Industries) were sent to the conferences from Japan (JNC).
The local attendees were as follows:—Vienna conference (second): T. Arendt (EAS), A. Ballarino (CERN), T. Taylor (CERN), J. Sosnowski(Poland), T. Shintomi (Nihon University), K. Sato (Sumitomo Electric Industries), and K. Osamura (Kyoto
University)—Genoa conference (third): R. Heller (FzK), W. Fietz (FzK), H. Krauth (EAS), T. Taylor (CERN), T. Mito
(National Institute for Fusion Science), T. Shintomi (Nihon University), K. Sato (Sumitomo ElectricIndustries), K. Osamura (Kyoto University)
The purpose of ad hoc group 1 is to have international specialists debate the necessity for international
standards of current leads, which are essential to superconducting equipment, and to report the results of its
activities and the direction of standardization at the IEC/TC90 international conferences.
An overview of the conferences is provided below.
(1) An international consensus was reached on the necessity for international standardization of current
leads, which are essential to superconducting equipment.
(2) Discussion was continued on the comments put forth by EU and U.S. members about the draft (ver. 7)
presented by the JNC.
(3) The title will be general current leads, and not be limited to superconducting current leads.
(4) The publishing of patent policy items will be deferred.
(5) The organization standards content will eliminate design items, explain the concept (principle) ofcurrent leads, and add a description of the essential characteristics for configuring current leads and acharacteristic test for them.
(6) Heat load, mass flow, pressure drop, voltage drop, high voltage measurements, safety margin in caseof loss of mass flow, and leak tightness—essential items for current leads—were mentioned ascharacteristic items essential to current leads.
(7) It was pointed out that a concrete elaboration would be better left until after the establishment of aworking group (WG).
Next, the ad-hoc group 1 conference will sum up the intentions of EU and U.S. members and thendetermine the appropriate direction to be taken after reaching agreement with ad hoc group 1 members.
(Published in a Japanese version in the November 2005 issue of Superconductivity Web 21)(Yasuzo Tanaka, Director, Standardization Department, ISTEC)

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