bluuebunny/crossref_metadata_2025 huggingface dataset:
Multilocus Variable-Number Tandem-Repeat Analysis for Investigation of
Clostridium difficile
Transmission in Hospitals
Authors: Marsh Jane W. , O'Leary Mary M. , Shutt Kathleen A. , Pasculle A. William , Johnson Stuart , Gerding Dale N. , Muto Carlene A. , Harrison Lee H.
Published: July 2006

Clostridium difficile
is a major cause of antibiotic-associated gastrointestinal illness. Recently, an increased incidence of hospital-acquired infections with severe outcomes has been reported in North America and Europe. Current molecular-typing methods for detection of outbreaks and nosocomial transmission are labor-intensive, subjective, or insufficiently discriminatory to differentiate between closely related strains. This report describes the development of multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) for molecular subtyping of
C. difficile
. Seven VNTR loci were identified from the
C. difficile
630 genome by screening an isolate collection of various restriction endonuclease analysis (REA) types. The stability of the loci for short-term epidemiologic investigations was determined by performing MLVA on consecutive isolates of the same REA type from individual patients collected over as many as 90 days. Validation of MLVA for molecular genotyping was performed by direct comparison with REA results obtained from Hines Veterans Affairs Hospital on a combined collection of 40
C. difficile
isolates from two different sources. The ability of MLVA to detect outbreaks was demonstrated on a collection of tertiary-care hospital isolates from a defined
C. difficile
outbreak in 2001. MLVA successfully clustered
C. difficile
isolates of the same REA type and discriminated isolates of unique REA type. Thus, MLVA is an objective, portable genotyping method that permits reliable detection of
C. difficile
outbreaks and can aid epidemiologic investigations of nosocomial transmission.
Survey of Dogs in Japan for Group 2 Canine Coronavirus Infection
Authors: Yachi Akiko , Mochizuki Masami
Published: July 2006

Specimens obtained from 96 dogs with respiratory and enteric clinical signs in Japan were retrospectively examined for group 2 coronavirus by reverse transcription-PCR. Two dogs were found to be positive. Phylogenetic analysis of the spike gene indicated that they were most probably related to the canine respiratory coronavirus recently described in the United Kingdom.
Assessment of MagNA Pure LC Extraction System for Detection of Human Papillomavirus (HPV) DNA in PreservCyt Samples by the Roche AMPLICOR and LINEAR ARRAY HPV Tests
Authors: Stevens Matthew P. , Rudland Elice , Garland Suzanne M. , Tabrizi Sepehr N.
Published: July 2006

Roche Molecular Systems recently released two PCR-based assays, AMPLICOR and LINEAR ARRAY (LA), for the detection and genotyping, respectively, of human papillomaviruses (HPVs). The manual specimen processing method recommended for use with both assays, AmpliLute, can be time-consuming and labor-intensive and is open to potential specimen cross-contamination. We evaluated the Roche MagNA Pure LC (MP) as an alternative for specimen processing prior to use with either assay. DNA was extracted from cervical brushings, collected in PreservCyt media, by AmpliLute and MP using DNA-I and Total Nucleic Acid (TNA) kits, from 150 patients with histologically confirmed cervical abnormalities. DNA was amplified and detected by AMPLICOR and the LA HPV test. Concordances of 96.5% (139 of 144) (κ = 0.93) and 95.1% (135 of 142) (κ = 0.90) were generated by AMPLICOR when we compared DNA extracts from AmpliLute to MP DNA-I and TNA, respectively. The HPV genotype profiles were identical in 78.7 and 74.7% of samples between AmpliLute and DNA-I or TNA, respectively. To improve LA concordance, all 150 specimens were extracted by MP DNA-I protocol after the centrifugation of 1-ml PreservCyt samples. This modified approach improved HPV genotype concordance levels between AmpliLute and MP DNA-I to 88.0% (
P
= 0.043) without affecting AMPLICOR sensitivity. Laboratories that have an automated MP extraction system would find this procedure more feasible and easier to handle than the recommended manual extraction method and could substitute such extractions for AMPLICOR and LA HPV tests once internally validated.
Decrease in eccentric hamstring strength in runners in the Tirol Speed Marathon
Authors: Koller A , Sumann G , Schobersberger W , Hoertnagl H , Haid C
Published: July 2006

Background:The local muscular endurance of knee flexors, during eccentric work in particular, is important in preventing or delaying kinematic changes associated with fatigue during treadmill running. This result, however, may not be transferable to overground running.

Objective:To test the hypothesis that overground running is associated with eccentric hamstring fatigue.

Methods:Thirteen runners (12 male and one female) performed an isokinetic muscle test three to four days before and 18 hours after a marathon. Both legs were tested. The testing protocol consisted of concentric and eccentric quadriceps and hamstring contractions.

Results:There were no significant differences between peak torque before and after the race, except that eccentric peak hamstring torque (both thighs) was reduced.

Conclusion:Overground running (running a marathon) is associated with eccentric hamstring fatigue. Eccentric hamstring fatigue may be a potential risk factor for knee and soft tissue injuries during running. Eccentric hamstring training should therefore be introduced as an integral part of the training programme of runners.
LOCALIZATIONS AT INFINITY AND ESSENTIAL SPECTRUM OF QUANTUM HAMILTONIANS I: GENERAL THEORY
Authors: GEORGESCU VLADIMIR , IFTIMOVICI ANDREI
Published: July 2006

We isolate a large class of self-adjoint operators H whose essential spectrum is determined by their behavior at x ~ ∞ and we give a canonical representation of σ ess (H) in terms of spectra of limits at infinity of translations of H.
RIGOROUS STEPS TOWARDS HOLOGRAPHY IN ASYMPTOTICALLY FLAT SPACETIMES
Authors: DAPPIAGGI CLAUDIO , MORETTI VALTER , PINAMONTI NICOLA
Published: July 2006

Scalar QFT on the boundary ℑ+at future null infinity of a general asymptotically flat 4D spacetime is constructed using the algebraic approach based on Weyl algebra associated to a BMS-invariant symplectic form. The constructed theory turns out to be invariant under a suitable strongly-continuous unitary representation of the BMS group with manifest meaning when the fields are interpreted as suitable extensions to ℑ+of massless minimally coupled fields propagating in the bulk. The group theoretical analysis of the found unitary BMS representation proves that such a field on ℑ+coincides with the natural wave function constructed out of the unitary BMS irreducible representation induced from the little group Δ, the semidirect product between SO(2) and the two-dimensional translations group. This wave function is massless with respect to the notion of mass for BMS representation theory. The presented result proposes a natural criterion to solve the long-standing problem of the topology of BMS group. Indeed the found natural correspondence of quantum field theories holds only if the BMS group is equipped with the nuclear topology rejecting instead the Hilbert one. Eventually, some theorems towards a holographic description on ℑ+of QFT in the bulk are established at level of C*-algebras of fields for asymptotically flat at null infinity spacetimes. It is proved that preservation of a certain symplectic form implies the existence of an injective *-homomorphism from the Weyl algebra of fields of the bulk into that associated with the boundary ℑ+. Those results are, in particular, applied to 4D Minkowski spacetime where a nice interplay between Poincaré invariance in the bulk and BMS invariance on the boundary at null infinity is established at the level of QFT. It arises that, in this case, the *-homomorphism admits unitary implementation and Minkowski vacuum is mapped into the BMS invariant vacuum on ℑ+.
EFFECTS OF PLASMA SHIELDING ON PULSED LASER ABLATION
Authors: ZHANG DUANMING , LIU DAN , LI ZHIHUA , HOU SIPU , YU BOMING , GUAN LI , TAN XINYU , LI LI
Published: July 2006

We have developed a theoretical model which studies the characteristics of laser-plasma interaction, the effect of plasma shielding and plasma radiation in the ablation process. The model is used to simulate 25 ns square pulsed laser irradiation on YBa 2 Cu 3 O 7 targets, and pulsed laser with the pulse width of 25 ns (FWHM) irradiation on Ni targets. The evolution of the plasma length and the transmitted intensity are performed. The model shows the variation of ablation depth with energy density. Moreover, we obtain the dependence of the ablation depth on the number of laser pulses. The satisfactorily good agreement between our results and experimental results confirms that plasma shielding plays a relevant role in the ablation process.
MECHANICAL AND THERMOELECTRIC PROPERTIES OF HIGHER MANGANESE SILICIDE FILMS
Authors: HOU Q. R. , CHEN Y. B. , HE Y. J.
Published: July 2006

Higher manganese silicide (HMS, MnSi 1.7) films have been deposited on glass, silicon and thermally oxidized silicon substrates by the methods of magnetron sputtering and thermal evaporation. Mechanical and thermo-electric properties of the films have been measured. The hardness and elastic modulus of the films are 10.0~14.5 GPa and 156~228 GPa, respectively. The sign of the Seebeck coefficient at room temperature is positive for all samples. The resistivity at room temperature is between 0.53×10-3 and 45.6×10-3 ohm-cm. The energy band gap calculated from the resistivity data for the film deposited on thermally oxidized silicon substrate is about 0.459 eV.
AC SUSCEPTIBILITY OF YBCO SUPERCONDUCTING THIN FILMS
Authors: SBÂRCIOG C. , REDAC T. R. , GR. DEAC I.
Published: July 2006

Ca -doped (x = 0.00, 0.07 and 0.20) epitaxial Y 1-x Ca x Ba 2 Cu 3 O 7-δ thin films were prepared on SrTiO 3 (100) by PLD technique. The superconducting transition temperature is found to decrease with increasing Ca content. The AC-susceptibility data were used to determine the intergranular critical current density, when varying the field amplitude H AC . The temperature dependence of critical current density was determined from the imaginary part of the complex susceptibility, χ′′(T), using Xing's relation. The results were analyzed in terms of superconductor-insulator-superconductor (SIS) and superconductor-normal-superconductor (SNS) type models.
ELECTRONIC STATES IN INTERCALATION MATERIALS STUDIED BY ELECTROCHEMICAL TECHNIQUES
Authors: NIKLASSON GUNNAR A. , AHUJA RAJEEV , STRØMME MARIA
Published: July 2006

In this paper, we present a novel method to study the electronic density-of-states of intercalation materials. We present evidence that electrochemical quasi-steady state potential curves of a number of materials exhibit fine structure in striking agreement with the density of electronic states, as obtained from ab initio calculations. The ability to probe the electronic structure by our electrochemical technique seems, in most cases, to be restricted to disordered materials. We suggest that localization of the band states is essential, in order for the technique to give a good picture of their density. The electrochemical density of states is often smaller than the computed one due to kinetic effects, i.e. very slow relaxations of the charge carriers. Our highly sensitive electrochemical method opens new vistas for studying the electronic structure of disordered materials, that can be intercalated with an ionic species.
COINCIDENCES BETWEEN THE GRAVITATIONAL WAVE DETECTORS EXPLORER AND NAUTILUS IN 1998, DURING THE ACTIVITIES OF THE BLACK HOLE CANDIDATE XTE J1550-564 AND THE MAGNETAR SGR1900+14
Authors: MODENA I. , PIZZELLA G.
Published: July 2006

The coincidence excess between the gravitational wave detectors EXPLORER and NAUTILUS observed in the ten-day period 7–17 September 1998 is the largest ever observed. The event occurred mainly at the sidereal hour 4, when the detectors axes were perpendicular to the Galactic disk. This excess occurred during a period of intense activity of the black hole candidate XTE J1550-564, and within days of the giant flare from the magnetar SGR1900+14.
ON THE ADM DECOMPOSITION OF THE 5-D KALUZA–KLEIN MODEL
Authors: LACQUANITI VALENTINO , MONTANI GIOVANNI
Published: July 2006

Our purpose is to recast the KK model in terms of ADM variables. We examine and solve the problem of the consistency of this approach, with particular care about the role of the cylindricity hypothesis. We show in detail how the KK reduction commutes with the ADM slicing procedure and how this leads to a well-defined and unique ADM reformulation. This allows us to consider the Hamiltonian formulation of the model and moreover it can be viewed as the first step for the Ashtekar reformulation of the KK scheme. Moreover, we show how the time component of the gage vector arises naturally from the geometrical constraints of the dynamics; this is a positive check for the autoconsistency of the KK theory and for an Hamiltonian description of the dynamics which will take into account the compactification scenario; this result enforces the physical meaning of the KK model.
Improvement of Reliability in Low-Temperature Polycrystalline Silicon Thin-Film Transistors by Water Vapor Annealing
Authors: Uraoka Yukiharu , Miyashita Makoto , Sugawara Yuta , Yano Hiroshi , Hatayama Tomoaki , Fuyuki Takashi , Sameshima Toshiyuki
Published: July 2006

Low-temperature polycrystalline silicon (poly-Si) thin film transistors (TFTs) are promising for realizing future displays such as a system-on-panel. Reliability is one of the most important issues for realizing system-on-panel. We performed water vapor annealing to improve reliability. To investigate the effect on the hot carrier effect, we imposed DC stress on a TFT with and without water vapor annealing. Degradation by the hot carrier effect was improved by the treatment. Analysis by emission microscope revealed that hot electron generation was enhanced by the treatment. To study the effect on thermal degradation, we also imposed DC stress on the TFT with and without the treatment. Degradation induced by Joule heating was also greatly improved. Analysis by thermal infrared imaging system revealed that operating temperature increased due to improved performance. We discussed the model for the treatment. Water vapor annealing improved the hot carrier effect and thermal degradation by reinforcing the Si–Si or Si–O bonding with activated oxygen.
Performances of Ni-Induced Lateral Crystallization Thin Film Transistors with <111 > and <112 > Needle Grains
Authors: Hou Chih-Yuan , Wu YewChung Sermon
Published: July 2006

Thin-film transistors (TFTs) fabricated using <111 > and <112 > needle grains have been investigated. They were fabricated by Ni–metal-induced lateral crystallization and Ni–metal imprint-induced crystallization method. It is found that the performance of 112-TFT was far superior to that of 111-TFT. The device transfer characteristics of 112-TFT include 2.6-fold-higher field-effect mobility (µFE), 4-fold-higher on/off current ratio (I
on/I
off), and 2.4-fold-lower leakage current (I
off) compared with those of the 111-TFT.
Effect of the Structural Change of Hydrogenated Microcrystalline Silicon Thin Films Prepared by Hot-Wire Chemical Vapor Deposition
Authors: Hiza Shuichi , Matsuda Wataru , Yamada Akira , Konagai Makoto
Published: July 2006

Hydrogenated microcrystalline silicon (µc-Si:H) thin films and solar cells were prepared by the hot-wire chemical vapor deposition (HWCVD) with various hydrogen dilution conditions. The surface of the film was observed by scanning electron microscopy (SEM) and the atomic force microscopy (AFM). From the observation, we observed that the films deposited at lower hydrogen dilution ratios [films with lower crystalline volume fractions (X
C)] had rough surfaces with large crystalline aggregations with diameters larger than 100 nm. Conversely, the films deposited at higher hydrogen dilution ratios (films with higher X
C) had almost smooth surface with smaller aggregations. In other words, the number of boundaries between crystalline aggregations increased with hydrogen dilution ratio. These structural changes agreed with the results of the spin density and ambipolar diffusion length measurements, which showed a tendency to deteriorate with the higher X
C. The performance of the fabricated solar cells showed a similar change with hydrogen dilution ratio, i.e., a lower hydrogen dilution ratio resulted in a higher quality device. However, too low a hydrogen dilution ratio resulted in the degradation of the solar cell performance originating from the amorphous incubation layer grown at the p–i interface.
Planarization of Si Ridges in Sequential Lateral Solidification Process
Authors: Moon Jaehyun , Sohn Choong-Yong , Kim Yong-Hae , Chung Choong-Heui , Lee Jin Ho
Published: July 2006

The heights of ridges, which are formed after crystallizing amorphous Si films, vary linearly to the initial film thicknesses. Post laser treatments on ridges have an effect of leveling the heights of ridges and lead to improved thin-film transistor characteristics. Relevant parameters influencing the planarization process are discussed. The optimum energy for planarization corresponds to the energy at which ridge peak blunting is maximum.
Novel Interface Properties of Au Overlayer on Top of C60 Polycrystalline Film
Authors: Liao Jian-Liang , Chiu Kuan-Cheng
Published: July 2006

From a temperature dependence of the dark electrical conductivity of Au overlayer σM(T) measured along the interface direction on top of a C60 polycrystalline film, a dramatic change in σM is observed at T ≈255 K; σM(T) increases with increasing temperature. As deduced from σM versus 1/T, an activation energy of 200 ±30 meV for T<255 K is much larger than that of 59 ±2 meV for T>255 K. These novel phenomena are explained by structural–electronic interaction on the Au/C60 interface with a change in the properties of the induced surface states due to the rotational order/disorder phase transition.
Ultra-Shallow Junction Formation by Non-Melt Laser Spike Annealing and its Application to Complementary Metal Oxide Semiconductor Devices in 65-nm Node
Authors: Shima Akio , Hiraiwa Atsushi
Published: July 2006

We activated source/drain junctions of complementary metal oxide semiconductor (CMOS) by simply replacing rapid thermal annealing (RTA) in the conventional production flow by non-melt laser spike annealing (LSA). We did not form any additional layers, unlike the conventional laser annealing. The 50-nm gate CMOS devices thus formed had overwhelmingly better V
th roll-offs and larger drain currents compared to those formed by RTA. We found that the LSA-devices without offset spacers had better performance than those with offset spacers, and that the optimization of the overlap length between the gate and source/drain extensions was important due to the minimal lateral diffusion during the sub-millisecond annealing of LSA.
A Theoretical Analysis of Electromigration Failure in Aluminum Interconnections
Authors: Nemoto Takenao , Jr. A. Toshimitsu Yokobori, , Murakawa Tsutomu
Published: July 2006

Electromigration was analyzed mathematically by solving Huntington's equation. A general solution assuming steady-state conditions was derived by Fourier transformation and complex integration. The analysis revealed that a significant accumulation of atoms at the anode induced hillock formation, and that atomic depletion at the cathode induced void formation. An electromigration acceleration test was performed to observe void formation using Al–0.5%Cu–1.0%Si on a SiO2/Si substrate. Experimental results of in situ observation were in good agreement with the theoretical result. The effect of a local stress field on void formation is discussed.
Novel Quaternary AlInGaN/GaN Heterostructure Field Effect Transistors on Sapphire Substrate
Authors: Liu Yang , Egawa Takashi , Jiang Hao , Zhang Baijun , Ishikawa Hiroyasu
Published: July 2006

Undoped quaternary Al
x
In0.02Ga0.98-x
N/GaN heterostructure field effect transistors (HFET) with different Al mole fractions were fabricated on sapphire substrate. An enhancement in two-dimensional electron gas density with increasing the Al mole fractions was observed. The properties of HFETs revealed that, with the Al incorporation, both maximum transconductance (g
mmax) and drain current (I
dmax) increased up to 138 mS/mm and 1230 mA/mm, respectively, for the device with 2 µm gate length. In addition, the threshold voltage strongly depended on Al mole fraction, by which normally-off HFET was demonstrated on a low Al-contained sample. No breakdown was observed for all the Al
x
In0.02Ga0.98-x
N/GaN HFETs when the gate–drain reverse bias was applied up to 100 V. The results indicate that quaternary AlInGaN is a promising candidate for high power and high frequency device applications.
Atomic Force Microscope Based Lithography of YBa2Cu3O7-δ Thin Films
Authors: Wimbush Stuart C. , Tachiki Minoru , Takayama-Muromachi Eiji , Itozaki Hideo
Published: July 2006

We demonstrate the patterning of controlled, arbitrary structures into the surface of thin film YBa2Cu3O7-δ samples by application of a bias voltage between the sample and the tip of an atomic force microscope operated in contact mode, and programmed to trace out the desired structure. The modified volume, as observed above the film surface, is shown to increase linearly with the applied bias voltage, beyond some threshold value, suggesting an electrochemical anodisation process, while increasing the scan speed results in a decrease in the modified volume, but an apparent improvement in homogeneity. Energy dispersive X-ray measurements support the scenario of oxidation as the means of modification, while measurements of current flow into the modified region indicate that it is insulating, offering potential application of the technique to the fabrication of superconducting device elements.
Femtosecond Pulse Delivery through Long Multimode Fiber Using Adaptive Pulse Synthesis
Authors: Itoh Haruyasu , Urakami Tsuneyuki , Aoshima Shin-ichiro , Tsuchiya Yutaka
Published: July 2006

We report on a delivery technique for 164-fs optical pulses with a peak power of 1.1 kW through a long multimode optical fiber and a glass block using an adaptive pulse-shaping feedback loop. We used two devices to optimize the input pulse; a pulse stretcher and a pulse shaper. 382-ps chirped pulses are compressed to 370-fs pulses at the output end of a glass block joined to a standard graded-index multimode fiber, 96 m in length and with a core diameter of 50 µm (the output end of the system). The adaptive pulse shaper compensates for the remaining high-order phase dispersion, which results in 164-fs pulses at the output end of the system. Our work shows that an adaptive pulse synthesis technique provides a powerful and convenient technique for programmable fiber dispersion compensation over a broad optical bandwidth.
Compact Arrayed-Waveguide Grating with Multiple-Arrowhead Structures
Authors: Suzuki Takanori , Tsuda Hiroyuki
Published: July 2006

A compact arrayed-waveguide grating (AWG) using multiple-arrowhead structures has been proposed. Arrowhead structures are useful for achieving low-cost and highly integrated waveguide devices because of their compactness. Therefore, the use of multiple-arrowhead structures enables us to achieve high-resolution AWGs with a channel spacing of less than 10 GHz, and we have already fabricated an 8-channel, 25-GHz-spacing AWG using a single-arrowhead structure, a 16-channel, 100-GHz-spacing AWG using a double-arrowhead structure and an 8-channel, 6.25-GHz-spacing AWG using a triple-arrowhead structure. The dimension of the third type of AWG is much smaller than a conventional AWG, with a size ratio of 1:6.4. The levels of the losses and adjacent crosstalk are mainly determined by insertion losses in the v-bend waveguides and by phase shifts due to misalignment of the mirror position, respectively.
A Theoretical Study of the Effect of Eu ion Dopant on the Electronic Excitations of Yttrium Oxide and Yttrium Oxy-Sulphide
Authors: Govindasamy Agalya , Lv Chen , Tsuboi Hideyuki , Koyama Michihisa , Endou Akira , Kubo Momoji , Broclawik Ewa , Miyamoto Akira
Published: July 2006

Recently, lanthanide ion doped yttrium oxide (Y2O3) compounds have been attracting attention in applications concerning opto-electronic materials such as laser devices and field-emission displays. Consequently, study on the excited state of lanthanide ion doped Y2O3 is of major significance. In the present work, we report studies performed on the electronic excited states of undoped and Eu3+ doped Y2O3 as well as yttrium oxy-sulphide (Y2O2S) clusters using the time dependent density functional theory method to unveil the influence of europium ion in yttrium oxide compounds. The ground state electronic properties of undoped and europium ion doped clusters at different spin multiplicities were obtained using the density functional theory method. The calculated results were compared with the available experimental results. The calculated absorption spectrum of Eu doped Y2O3 cluster shows quantitative agreement with experimental spectra. The absorption spectra of europium ion doped Y2O3 and Y2O2S clusters have shown additional bands in the higher wavelength region due to the transitions between f-orbitals in the europium ion.
AgGaGeS4Crystals for Nonlinear Laser Device Applications
Authors: Das Subhasis , Ghosh Chittaranjan , Gangopadhyay Sudipta , Andreev Yuri M. , Badikov Valiry V.
Published: July 2006

A mid-infrared frequency converter with a nonlinear crystal, AgxGaxGe(1-x)S4(AgGaGeS4), forx=0.5 has been reported by the second harmonic generation of tunable CO2laser radiation. Two pole coefficients of Sellmeier equations are also presented.
Micro-Magnetic Suspension Motor Design for Miniature Optical Drive
Authors: Wang Chien-Chang , Yao Yeong-Der , Liu Chien-Sheng , Cheng Lung-Yu
Published: July 2006

The main purpose of this study is to develop a low vibration micromotor applied in a miniature optical drive. To minimize the micromotor vibration, passive magnetic suspension technology has been used. The magnetic forces between the permanent magnets are estimated using the finite element method; the stable zone of operation of the motor developed was determined. A new micromotor with 62% of the radial vibration of the conventional micro-ball-bearing motor has been successfully developed. In addition, the new motor demonstrates lower friction torque loss.
New Structure of Optical Fiber Protection Cable Using Helical Composite Spring
Authors: Chung Seunghwan , Yoon Youngki , Lee Woo-Il , Lee Byoungho
Published: July 2006

A new type of cable is introduced for protecting optical fiber from mechanical bending or abrupt temperature changes. It shows superior ability to protect fiber from severe bending and lowers the thermal sensitivity compared with conventional optical fiber cable. It can be used as a protection sleeve or cable in special regions. The proposed device consists of a helical composite spring, a thermal insulator (i.e., polyurethane foam) and a heat-shrinkable tube which coats the outside of the spring. These components can be acquired for a moderate price and manufactured by simple processes.
Spherical Aberration Error Detection for Blu-ray Disc Optical Pickups
Authors: Ogata Nobuo , Kanazawa Yasunori , Horiyama Makoto , Nishioka Sumito , Miyake Takahiro , Nakata Yasuo , Kurata Yukio
Published: July 2006

For a high-numerical-aperture (NA) optical pickup system, the spherical aberration (SA) caused by cover layer thickness error should be corrected. We detected the SA error signal using a newly designed hologram optical element (HOE). The HOE has both sufficient signal sensitivity and constant signal level independent of objective lens shift. In addition, we fabricated on SA servo for a dual-layer Blu-ray disc.
Critical Voltage of π-Cell Liquid Crystal Displays
Authors: Sun Yubao , Ma Hongmei , Li Zaidong , Zhang Zhidong
Published: July 2006

The critical voltage is investigated theoretically for π-cell with arbitrary pretilt angle. Our results show that the analytical critical voltage decreases as the pretilt angle increases, which is consistent with the numerical and experimental data. We also find that the critical voltage is dependent on the pretilt angle and the splay and bend elastic parameters of liquid crystal material, but independent on the cell gap.
Photoluminescence of Erbium-Doped Potassium Tantalate Niobate Polycrystalline
Authors: Wen Cheng-Hung , Chu Sheng-Yuan , Shin Yan-Yu , Wen Cheng-Kuo
Published: July 2006

In this study, we investigated the luminescence properties of erbium-doped potassium tantalite niobate (KTa
x
Nb1-x
O3 or KTN) ceramics, which were prepared by the conventional solid-state reaction synthesis method. In this work, we studied the relationships of the crystal structure, and Raman and photoluminescence (PL) spectra with the tantalum concentration, respectively. The experiments showed that the tantalum dopants modified the intensity of the green, red and near-infrared emission bands. The experiments also showed a blue shift for the 2 mol % erbium doped KTN samples with different tantalum compositions. Doping Ta not only led to the change in PL intensity but also in spectral shapes. The PL spectra showed the splitting peaks for the samples with low Ta compositions. Then these peaks combined and broadened as Ta concentration increase. When Ta was substituted for Nb completely, the luminescence intensity of the green emission band had an increase of approximately about one order of magnitude, which was because of the absence of the first-order phonon relaxation in the high-Ta-concentration samples.
Proposal for BexZn1-xS Barrier Layers Combined with ZnS Wells
Authors: Onodera Chikara , Shoji Tadayoshi , Hiratate Yukio , Taguchi Tsunemasa
Published: July 2006

We have performed a theoretical study of exciton binding energy and effective band gap energy in ZnS/Be
x
Zn1-x
S single quantum wells (SQWs). With increasing beryllium (Be) content (x), conduction and valence band offsets increase in ZnS/Be
x
Zn1-x
S SQWs and thus exciton binding energy increases. We conclude that the Be
x
Zn1-x
S barrier layer is useful for designing ZnS-based quantum wells (QWs).
Modeling of Piezoelectric Energy Harvesting Using Cymbal Transducers
Authors: Kim Hyeoungwoo , Priya Shashank , Uchino Kenji
Published: July 2006

This study reports the experimental and analytical results on a piezoelectric cymbal with 29 mm diameter and 1 mm thickness operating under force of 70 N in the frequency range of 10–200 Hz. It was found that the generated power increases with the frequency and around 100 mW can be harvested at frequency of 200 Hz across a 200 kΩ resistor. Power generation from the cymbal transducer was modeled by using the theory developed for the Belleville spring. The calculated results were found to be in good agreement with the experimental results. The results indicate that the metal–ceramic composite transducer “CYMBAL” is the most promising structure for harvesting the electric energy from automobile engine vibrations. The metal cap enhances the endurance of the ceramic to sustain high loads along with stress amplification.
Effects of Dopant on the Dielectric Properties of CaZrO3 Ceramic Sintered in a Reducing Atmosphere
Authors: Lee W. S. , Su C. Y. , Lee Y. C. , Lin S. P. , Yang Tony
Published: July 2006

In this study, the influence of CaZrO3 doped with three dopants, SiO2, MnO, and Nb2O5, and then sintered in a reducing atmosphere on microstructure, phase formation, and electrical properties is investigated. SiO2 plays the role of sintering aid to enhance the density of CaZrO3 leading to better performance of electrical properties as a function of SiO2 content. MnO, and Nb2O5 were incorporated into the Zr-site of CaZrO3 to make stoichometric CaZrO3 into non-stoichiometric CaZrO3 with Zr excess resulting in the formation of a second phase, CaZr4O9, which has a lower dielectric constant (13) in comparison with that of the main phase of CaZrO3 (32). Thus, the dielectric constant of CaZrO3 doped with Nb2O5, or MnO is decreased markedly. In addition, Mn+2 incorporated into Zr-sites of CaZrO3 plays the role of acceptor, which compensates for the number of conduction electrons and contributes to better performance of electrical properties such as insulation resistance and tan
δ. Conversely, Nb+5 incorporated into Zr-sites of CaZrO3 plays the role of donor and provides more conduction electrons, leading to poor performance of electrical properties.
Microwave Dielectric Properties of Dy2O3 Substituted BiNbO4 Ceramics
Authors: Lim Hyuk , Oh Young-Jei
Published: July 2006

The microwave dielectric properties of Bi1-x
Dy
x
NbO4 ceramics were investigated as a function of Dy3+ substitution (0≤x≤0.1). Bi1-x
Dy
x
NbO4 compositions prepared at low temperatures (900–960 °C). A single orthorhombic (α-BiNbO4) phase in all Bi1-x
Dy
x
NbO4 compositions was obtained for the whole sintering temperature range. The decrease in the dielectric constant of the Bi1-x
Dy
x
NbO4 ceramics with increasing Dy content is attributed to the decrease in polarizability as Dy is substituted to the Bi site. The decrease in the temperature coefficient of the resonant frequency is due to the distortion of the oxygen octahedra.
Realization of Grayscale Memory Operation in a Step-Growth Based Polymer-Stabilized Ferroelectric Liquid Crystal System
Authors: Lee Ji-Hoon , Lim Tong-Kun , Kwon Young-Wan , Jin Jung-Il , Kwon Soon-Bum , Shin Sung-Tae
Published: July 2006

A grayscale memory states operation can be realized in which the liquid crystal directors are uniformly aligned in each state. This operation is realized by a specific morphology of polymers obtained through step-growth polymerization of a thiol–ene stabilizing the ferroelectric liquid crystal system. The continuous director rotation (CDR) of liquid crystal (LC) molecules as well as the grayscale memory behavior is observed where the LC directors are oriented uniformly in each state. The memory operation is due to the interaction of LC molecules with the thiols intercalated in the smectic layer with one end of each thiol bound to the polymerized ene in the inter-layer planes. The morphology of the polymer in the liquid crystal plays a crucial role in the existence of grayscale memory behavior, and the morphology depends strongly on the phase of the sample when the thiol-ene monomers are polymerized. A new mechanism is suggested for the CDR motion of the ferroelectric liquid crystal (FLC).
Thermal and Optical Properties of Yb3+-Doped Y2O3 Single Crystal Grown by the Micro-Pulling-Down Method
Authors: Mun Ji Hun , Jouini Anis , Novoselov Andrey , Yoshikawa Akira , Kasamoto Tsuyoshi , Ohta Hiromich , Shibata Hiroyuki , Isshiki Minoru , Waseda Yoshio , Boulon Georges , Fukuda Tsuguo
Published: July 2006

Refractory rare-earth sesquioxides (RE2O3, RE = Y, Lu, Sc) are promising host materials for solid-state lasers due to low phonon energy and high thermal conductivity. In this work, we investigated thermodynamic properties of Yb3+-doped Y2O3 single crystals, doping level ≤15 mol % Yb3+ grown by the micro-pulling-down method (µ-PD). The thermal diffusivity lowers with increasing Yb3+ content from 7.2 to 2.37 ×10-6 m2 s-1, heat capacity from 0.44 to 0.403 J g-1 K-1, and thermal conductivity from 15.94 to 5.35 W m-1 K-1. Spectroscopic data are discussed.
Composition Dependence of the Critical Temperature in Mixed Ferro–Paraelectric Solid Solutions
Authors: Aragó C. , Marqués M. I. , Gonzalo J. A.
Published: July 2006

Previous work did show that the composition dependence of the Curie temperature T
c in mixed ferro–paraelectric solutions of hydrogen bonded ferroelectrics such as trisarcosine calcium chloride/trisarcosine calcium bromide (TSCC
x
B1-x
) can be described very well in the whole composition range, 0 ≤x ≤1, using an effective field approach which takes into account quantum effects related to zero point energy of the interacting dipoles. In this communication we report that an analysis of T
c(x) in mixed ferro-paraelectric solutions of oxide perovskite type ferroelectrics such as barium titanate/strontium titanate (B
x
S1-x
T) is also well described in the whole composition range by the same approach.
Time-Dependent Phase Transition of Self-Assembled Monolayers Formed by Thioacetyl-Terminated Tolanes on Au(111)
Authors: Jeong Youngdo , Lee Changjin , Ito Eisuke , Hara Masahiko , Noh Jaegeun
Published: July 2006

The binding conditions and time-dependent phase transition of self-assembled monolayers (SAMs) formed by thioacetyl-terminated tolane molecules on Au(111) were examined by X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). XPS measurements revealed that two S 2p3/2 XPS peaks of the tolanethioacetate (TTA) SAMs on Au(111) were observed at 162 eV (bound sulfur) and 163.4 eV (unbound sulfur). On the other hand, an additional strong S 2p3/2 XPS peak for the SAMs of tolane methylthioacetate (TMTA) that contained a methylene spacer between the tolane group and the sulfur atom was observed at 161.2 eV (bound sulfur). This suggested that the adsorption conditions of the tolane SAMs were strongly influenced by the difference in the chemical structure of the tolanes. It was found that TTA and TMTA molecules did not form ordered SAMs after the immersion of the Au(111) substrate in a 0.5 mM N,N'-dimethylformamide solution for 1 day. However, we observed a time-dependent phase transition of the TTA and TMTA SAMs from the disordered phase to the ordered phase as a result of a long-term structural rearrangement after incubation at room temperature for 10 days. These results will be very useful in understanding the formation and binding conditions of thioacetyl-terminated SAMs on Au(111) and in controlling the two-dimensional SAM structure.
Combinatorial Search for Low Resistivity Pd–Cu–Si Thin Film Metallic Glass Compositions
Authors: Yamauchi Ryusuke , Hata Seiichi , Sakurai Junpei , Shimokohbe Akira
Published: July 2006

A new combinatorial method to deposit thin films using an arc plasma, Combinatorial arc plasma deposition (CAPD), was applied to search for low resistivity compositions of Pd–Cu–Si thin film metallic glasses (TFMGs). The CAPD setup includes three arc plasma guns (APGs), with each gun shooting a pulse-like plasma of Pd, Cu or Si at specific time intervals to deposit a Pd–Cu–Si thin film on an SiO2 substrate. In this study, a Pd-based compositionally-graded thin film was deposited by controlling the number of shots as well as the plasma strength. The deposited thin film was separated into 1,089 samples (thin film library), and the thickness, composition, phase, and relative resistivity of each sample was evaluated without detaching them from the library. From the samples, three amorphous, low relative resistivity CAPD samples were identified. To verify that these samples were metallic glasses, their compositions were reproduced in samples deposited by sputtering, and their T
g (glass transition temperature) and T
x (crystallization temperature) were measured. The absolute resistivities of the three metallic glass samples were also measured. As the result, the Pd81Cu5Si14 at. % sample showed the lowest absolute resistivity of 64 µ Ω ·cm and a supercooled liquid region temperature range ( ΔT
x=T
x-T
g) of 50 K. This resistivity is 17% lower and the supercooled liquid region is almost two times larger than those of the known Pd-based TFMG composition.
Critical-Dimension Measurement using Multi-Angle-Scanning Method in Atomic Force Microscope
Authors: Murayama Ken , Gonda Satoshi , Koyanagi Hajime , Terasawa Tsuneo , Hosaka Sumio
Published: July 2006

We have developed a new critical dimension (CD) measurement technique using atomic force microscope (AFM) which can measure width-dimensions and examine sidewall-shapes of fine patterns on a wafer. The technique employs a flared-type tip in combination with digital probing and multi-angle scanning mechanism that allows the tip to trace the sidewalls on both sides of a feature (or trench) by making physical contacts with the sidewall surface. First, by using finite element method (FEM) we analyzed deformation of the tip and cantilever to compensate errors caused by the deformation. To verify our compensation method we measured quartz reference patterns either with perpendicular sidewalls or undercuts. In this paper we will describe the applications and usefulness of this multi-angle operation and show some measurement results of ArF resist patterns with 200 nm width and 400 nm depth that were obtained with a flared tip of 120 nm diameter.
Fabrication of Optically Active Er3+-Doped Bi2O3–SiO2 Glass Thin Films by Pulsed Laser Deposition
Authors: Akiba Shusaku , Takakura Masahiro , Matsuda Akifumi , Hara Wakana , Okada Takashi , Watanabe Takahiro , Kondo Yuki , Ito Setsuro , Ahmet Parhat , Chikyo Toyohiro , Tanabe Setsuhisa , Hanada Teiichi , Yoshimoto Mamoru
Published: July 2006

We examined the fabrication conditions of optically active Er3+-doped Bi2O3–SiO2 glass thin films prepared by pulsed laser deposition using a glass target with a nominal composition (mol %) of 41Bi2O3·57SiO2·2Er2O3. The transparent glass films were obtained at 200 °C under 5 ×10-2 Torr O2. The glass films were found to possess a composition and a refractive index close to those of the bulk glass used as the target. The films exhibited a broad emission of Er3+ ions at around 1.5–1.6 µm as well as Er3+ upconversion-pumped fluorescence in the 500–700 nm range.
Local Neutral Density Enhancement by Streaming Neutral Gas Injection
Authors: Mendenilla Alexander G. , Kasuya Toshiro , Wada Motoi
Published: July 2006

An array of nozzles arranged in a bicycle-wheel spoke pattern designed to create a region of high neutral gas density in an H- ion source was tested for its capability to generate a pressure gradient in a vacuum chamber. An experimental setup was designed and built to measure the local pressure around the nozzle array. The two-dimensional direct simulation Monte Carlo (DSMC) technique was employed to simulate the local pressure distribution around the nozzles and to compare the results with the measurements. Pressure measurements and DSMC simulations showed that the streaming neutral gas injection (SNGI) technique was capable of increasing the local pressure to 200% when the ambient pressure was 3.0 ×10-2 Pa. At higher ambient pressures, the enhancement factor decreased to 58% when the ambient was 2.8 Pa. A sloshing-type SNGI was also designed and the highest enhancement was 87% at an ambient pressure of 2.6 ×10-1 Pa.
ZnO Nanorods Synthesized by Self-Catalytic Method of Metal in Atmospheric Microwave Plasma Torch Flame
Authors: Hong Yong Cheol , Kim Jong Hun , Uhm Han Sup
Published: July 2006

Zinc oxide (ZnO) nanorods synthesized by an explosive oxidation reaction in a microwave plasma torch flame were presented. The structural characteristics and morphology of the as-synthesized ZnO nanorods were investigated by X-ray diffraction (XRD) analysis, field-emission scanning electron microscopy (FESEM), field-emission transmission electron microscopy (FETEM), and photoluminescence (PL) spectroscopy. It was revealed by FETEM that most of the ZnO nanorods were pure and had an average diameter of 80 nm and a length of up to 300 nm, and some ZnO nanorods had a hexagonal tip, tripod-like shape with a length of up to 1 µm. PL spectra show only strong UV emission at approximately 380 nm without any defect-related emissions, indicating good crystalline ZnO. Also, a possible mechanism of the growth of the ZnO nanorods is discussed.
Determination of Plasma Flow Velocity by Mach Probe and Triple Probe with Correction by Laser-Induced Fluorescence in Unmagnetized Plasmas
Authors: Choi Yong-Sup , Woo Hyun-Jong , Chung Kyu-Sun , Lee Myoung-Jae , Zimmerman David , McWilliams Roger
Published: July 2006

Plasma flow velocity was measured by Mach probe (MP) and laser-induced fluorescence (LIF) methods in unmagnetized plasmas with supersonic ion beams. Since the ion gyro-radius was much larger than the probe radius, unmagnetized Mach probe theory was used to determine plasma flow in argon RF plasma with a weak magnetic field (<200 G). In order to determine flow velocities, the Mach probe is calibrated via LIF in the absence of the ion beam, where existing probe theories may be valid although they use different geometries (sphere and plane) and analyzing tools [particle-in-cell (PIC) and kinetic models]. For the comparison of the average plasma flow velocities by MP and LIF, the supersonic ion beam velocity was measured by LIF and then incorporated into a simple formula for average plasma velocity with provisions for background plasma density and beam-corrected electron temperature (T
e) measured by a triple probe.
Extreme Ultraviolet Emission from Laser-Irradiated Low-Density Xe Targets
Authors: Ueda Nobuyoshi , Nagata Mizuho , Nishimura Hiroaki , Fujioka Shinsuke , Aota Tatsuya , Yasuda Yuzuri , Inubushi Yuichi , Ando Tsuyoshi , Norimatsu Takayoshi , Nakai Mitsuo , Nagai Keiji , Nishihara Katsunobu , Sunahara Atsushi , Miyanaga Noriaki , Izawa Yasukazu , Mima Kunioki
Published: July 2006

The effect of the initial density of xenon (Xe) targets on extreme ultraviolet (EUV) emission has been investigated. With decreasing initial density, it was found that the spectral width around 11 nm becomes broad, and the intensity of 13.5 nm emission increases. The maximum conversion efficiency (CE) for solid Xe targets is approximately 0.6% at a 2×1011 W/cm2 of laser intensity, whereas that for the low-density targets is approximately 0.7% at a 4×1011 W/cm2. The spectral broadening with decreasing initial density can be attributed to the change in optical thickness of laser-produced plasmas. The enhancement of CE is attributed to optically thick plasma formation.
Charge Carrier Transport in Red Electrophosphorescent Emitting Layer
Authors: Matsusue Noriyuki , Suzuki Yuichiro , Naito Hiroyoshi
Published: July 2006

The concentration dependence of bis(2-(2'-benzo[4,5-a]thienyl)pyridinato-N,C
3')iridium (acetylacetonate) [btp2Ir(acac)] in [btp2Ir(acac):4,4'-N,N'-dicarbazole-biphenyl] (CBP) thin films has been studied by time-of-flight transient photocurrent measurements. It is found that electron drift mobility is dramatically decreased at low btp2Ir(acac) concentrations (<1.5%) and is increased with the further addition of btp2Ir(acac) in btp2Ir(acac)-doped CBP thin films. The increase in electron drift mobility is due to electron hopping between btp2Ir(acac) molecules. In contrast, the hole transit signals of btp2Ir(acac)-doped CBP thin films were not observed.
Femtosecond Real-Time Pump-Probe Imaging Spectroscopy Implemented on a Single Shot Basis
Authors: Makishima Yoshinori , Furukawa Naoki , Ishida Akihiro , Takeda Jun
Published: July 2006

Real-time pump-probe imaging spectroscopy implemented on a single shot basis applicable to photochemical reaction dynamics in biological and organic materials is demonstrated in femtosecond time regime. Using this method, the accumulation time to measure transient signals becomes dramatically reduced, and we can successfully map time–frequency two-dimensional image of the absorbance changes of β-carotene in real-time with an accumulation of 20 laser shots.