bluuebunny/crossref_metadata_2025 huggingface dataset:
Boiler Flue-Gas Measurements Using a Dewpoint Meter
Authors: Clark N. D. , Childs G. D.
Published: January 2012

Corrosion and fouling of low temperature heat-transfer equipment poses one of the major obstacles to the achievement of maximum boiler operating efficiency. The first consideration in controlling or eliminating a problem of this nature is determination of its causes. Dewpoint-meter investigations for this purpose were performed on units fired by coal, oil, and various fuel combinations. The context of this paper presents a review of those factors thus revealed by these investigations as major contributors to plugging and corrosion processes in air preheaters installed on oil-fired boilers. These tests disclosed that corrosion potential of boiler flue gases is directly effected by the degree of boiler slagging. They have established that flue gas corrosion potential can be substantially reduced by decreasing the level of excess air employed in operation. The results of this study also indicate that maximum rate of condensation (peak rate, or PR) and the temperature of its occurrence (peak rate temperature, or PRT) are more reliable indicators of corrosion potential than the dewpoint.
A Pilot-Plant Investigation of Factors Affecting Low-Temperature Corrosion in Oil-Fired Boilers
Authors: Attig R. C. , Sedor P.
Published: January 2012

Methods for controlling or eliminating low-temperature corrosion are continually being sought to improve boiler availability and thermal efficiency. A small pilot plant was constructed at the authors’ company in which factors that affect low-temperature corrosion could be studied under closely controlled conditions. Results of tests on this unit show that: (a) The corrosion rate on carbon steel increases gradually as metal temperature falls below the acid dewpoint, passing through a peak at a metal temperature about 200 F. The corrosion rate then decreases as metal temperature continues to fall but begins to rise rapidly to extremely high values at temperatures just above the water dewpoint (⋍ 120 F). (b) Low-temperature corrosion of carbon steel can be practically eliminated if a method can be found for reducing the sulfur content of oil to about 0.5 percent. (c) The application of low-excess-air operation has the potential of eliminating low-temperature corrosion in boiler plants firing high-sulfur residual oils. (d) Corrosion of carbon steel above approximately 170 F can be reduced 30 percent or more by recirculating 25 percent of the flue gases to the burner. Future work will include a study of the effect of low-excess-air operation on high-temperature oil-ash corrosion and deposition and on the effect of oil ash on low-temperature corrosion.
Prevention of Residual Oil Combustion Problems by Use of Low Excess Air and Magnesium Additive
Authors: Reese J. T. , Jonakin J. , Caracristi V. Z.
Published: January 2012

High-temperature corrosion from low melting ash deposits, low-temperature corrosion, and low-temperature deposits produced by condensed sulfuric acid are three potential problems associated with residual fuel oil firing in steam generators. This paper discusses test work carried out on a large unit type steam generator in an effort to alleviate these problems through low-excess air operation and the use of a magnesium additive. Results indicate that these two steps are of significant help.
Boiler Feed Pump Drives
Authors: Goodell J. H. , Leung Paul
Published: January 2012

The purpose of this paper is to present a re´sume´ of boiler feed pump applications in major steam power stations in the last twelve years and to review criteria for the selection of feed pump drives in stations of different sizes and steam conditions to indicate the trend in selection of this type of equipment. Illustrative material from actual designs performed by the authors’ company is utilized.
The Application of Unsteady Gas-Dynamic Theories to the Exhaust System of Turbocharged Two-Stroke Engines
Authors: Woollatt D.
Published: January 2012

The paper reviews the methods available for solution of unsteady-flow problems and describes an approximate method which is suitable for numerical calculation on a digital computer. Results of calculations made by this method assuming homentropic, one-dimensional flow are compared with measured pressure versus crank-angle diagrams in the exhaust system of turbocharged two-stroke engines. It is considered that the results achieved are sufficiently accurate to be of use to the design or development engineer.
Losses in Vaneless Diffusers of Centrifugal Compressors and Pumps: Analysis, Experiment, and Design
Authors: Johnston J. P. , Dean R. C.
Published: January 2012

Two simple analyses are developed to predict losses in centrifugal compressor (or pump) vaneless diffusers: (a) One-dimensional, axisymmetric friction loss and (b) sudden-expansion mixing to account for losses in the diffuser caused by wakes of separated impeller blades. It is shown that these theories may be substituted for the more complex theory of Dean and Senoo [5]. Some experimental data are included to show the validity of the friction-loss analysis. Finally, the utility of the analyses in design is demonstrated.
On the Determination and Combination of Loss Coefficients for Compressible Fluid Flows
Authors: Benedict Robert P.
Published: January 2012

Experimentally based loss coefficients for typical globe valves and for associated piping systems are first determined according to an analytical method previously given. The series-combining characteristics of these separate loss coefficients are then studied, and general conclusions are drawn from these specific results. For a particular system, loss coefficients are also determined by the usual Darcy equations (which omit certain acceleration effects) to note the degree of approximation made both in the magnitude of the separate loss coefficients and in the series combination of these loss coefficients.
A Multi-Stage Slotted Blade Axial Flow Pump
Authors: Sheets Herman E. , Brancart Claude P.
Published: January 2012

A multi-stage axial flow pump offers the possibility of savings in space and weight and permits a compact arrangement. The use of slotted blades results in a high pressure rise per stage, thus reducing the necessary number of stages. Analysis of a single-stage pump, with regard to many potential effects of cavitation and flow analysis of the liquid passing through the slot, was made. The same unit was also analyzed with regard to performance both in water and air at respectively lower Reynolds numbers. Subsequently, a nine-stage pump was designed, built, and tested. In this arrangement an evaluation of blade numbers in both stators and impeller was analyzed. The test data showed an unusual phenomenon of increased pressure coefficient as compared with single-stage data.
The Design and Development of the Orenda OT-4 Gas Turbine
Authors: Quan D.
Published: January 2012

The Orenda OT-4 is a gas turbine which uses a simple regenerative cycle and is being developed as a multipurpose, continuous or emergency unit which will be competitive with the diesel engine and will retain the inherent advantages of the gas turbine. This development program is now in its fourth year. The design and development philosophies used in this engine are discussed briefly. The problems still facing the engine are indicated. Some of the experience and lessons learned from this program are discussed.
The Compact AK Process Nuclear System
Authors: Crim W. M. , Hoffmann J. R. , Manning G. B.
Published: January 2012

The paper is presented based on the concept, theories to be explored, initial design, detailed design, fabrication and construction, and initial testing in the first experimental, compact, closed-cycle (AK process) thermodynamic system. The thermodynamic basis of the closed-cycle-turbine power plant is the Ackeret-Keller or AK process which shows how maximum work can be attained between given temperature limits. Both the Carnot and AK cycles require isothermal compression and expansion over a moderate pressure ratio, the major difference between them being that the Carnot cycle requires the use of additional machinery and the AK cycle needs heat transfer apparatus to achieve the temperature range. Other advantages of the cycle are the low pressures and exotic gases that can be used, such as He and N2. The results of the experimental work to date have shown that the compact, closed gas cycle, employing the basic aerothermodynamic principles as discussed in the paper, can provide a feasible compact reactor system.
Research Study on Internal Corrosion of High-Pressure Boilers
Authors: Klein H. A. , Rice J. K.
Published: January 2012

This is the first progress report from an investigation being performed under the sponsorship of The American Society of Mechanical Engineers with joint financial support by the Edison Electric Institute, industry, and others concerned with the operation of high-pressure boilers.
Recent Progress in Aerodynamic Design of Axial-Flow Compressors in the United States
Authors: Serovy G. K.
Published: January 2012

This paper reviews recent trends in the United States in the aerodynamic design of axial-flow compressor components. A summary of design procedures used prior to 1955 is followed by discussion of subsequent improvements in the flow model, the velocity-diagram selection problem and methods for the selection or design of optimum blading. Recent investigations concerned with off-design performance, Reynolds number, scale and blade aspect ratio, and the influence that these investigations have had on design technique are considered. In conclusion, some important current problems in the design of axial-flow compressors are outlined.
Contribution on the Calculation of Gas Turbine Air Heaters Fired With Gas-Coal Mixtures
Authors: Bammert K. , Nickel E.
Published: January 2012

The design of heaters for closed-cycle gas turbines is different from that of steam generators. The main difference is found in the layout of combustion chambers; it is caused by the working fluid, the heat-transmission coefficient attainable in the tubes, and by the permissible pressure drops. The exact calculation of the heat transmitted in the combustion chamber and of the irradiation curve is a prerequisite for the economical layout of the heater combustion chamber. As suitable calculation methods were not known, the required basis was worked out by subjecting a mine-gas and pulverized-coal-fired combustion chamber of an existing plant to extensive tests. The paper deals with the test plant and the tests carried out. With the test results obtained at this and similar plants the correctness of calculation methods known for determining the heat transmission in pulverized-coal-fired combustion chambers was investigated. For the calculation of heaters, the Wohlenberg method is supplemented by taking higher heating-surface temperatures into consideration. A new method for calculating the irradiation curve in the combustion chamber is shown.
Thermodynamic Properties of Combustion Products: Equilibrium Products of (CH2)k With Oxygen Enriched Air
Authors: Pearson J. D. , Fellinger R. C.
Published: January 2012

Tables giving the enthalpy, entropy, molecular weight, constant composition specific heat ratio and constant composition sonic velocity of the equilibrium combustion products of (CH2)k with oxygen enriched air have been developed. The tables cover a temperature range of 2700 to 6120 deg R and pressures from 0.01 to 25 atm. Ratios of oxygen supplied range from 1.0 to 2.0 times the stoichiometric requirement. For each oxygen supply five values of the N/O ratio, ranging from 0 to 3.73, are considered. This paper presents two of these tables. They have a ratio of oxygen to stoichiometric oxygen 1.20 and N/O ratio of 2.0 and 3.73. Several sample problems illustrating use of the tables are given, including adiabatic flame temperatures, heat exchangers, and nozzles.
Steam Generators for Combined Steam and Gas Turbine Plants
Authors: Ecabert R. J.
Published: January 2012

Boilers designed for combined steam and gas turbine plants are compared to conventional ones. An analysis of the differences between the two systems leads to the following conclusions: (a) Plants with the gas turbine exhausting into the boiler furnace will remain confined to special applications; (b) plants with supercharged boilers look promising in view of the reduction in boiler size, weight, and cost which can be achieved. Such plants should be designed with emphasis placed on low first cost and high reliability rather than on low heat rate.
UPPER BOUNDS IN THE OHTSUKI–RILEY–SAKUMA PARTIAL ORDER ON 2-BRIDGE KNOTS
Authors: GARRABRANT SCOTT M. , HOSTE JIM , SHANAHAN PATRICK D.
Published: January 2012

In this paper we use continued fractions to study a partial order on the set of 2-bridge knots derived from the work of Ohtsuki, Riley, and Sakuma. We establish necessary and sufficient conditions for any set of 2-bridge knots to have an upper bound with respect to the partial order. Moreover, given any 2-bridge knot K1 we characterize all other 2-bridge knots K2 such that {K1, K2} has an upper bound. As an application we answer a question of Suzuki, showing that there is no upper bound for the set consisting of the trefoil and figure-eight knots.
STABLE SOLUTIONS ON MATCHING MODELS WITH QUOTA RESTRICTION
Authors: FEMENIA DELFINA , MARÍ MABEL , NEME ALEJANDRO , OVIEDO JORGE
Published: January 2012

In this paper, we present a matching market in which an institution has to hire a set of pairs of complementary workers, and has a quota that is the maximum number of candidates pair positions to be filled. We define a stable solution and first show that in the unrestricted institution preferences domain, the set of stable solution may be empty and second we obtain a complete characterization of the stable sets under responsive restriction of the institution's preference.
NON-INVASIVE TECHNIQUE FOR IN VIVO HUMAN EAR CANAL VOLUME MEASUREMENT
Authors: YU JEN-FANG , TSAI GO-LONG , FAN CHUNG-CHIEH , CHEN CHING-I , CHENG CHIA-CHI , CHEN CHENG-CHUNG
Published: January 2012

This prospective study is to develop a new non-invasive in vivo technique for the measurement of the human external auditory canal (EAC) volume using high resolution computed tomography (HRCT). Eighteen ears of nine male volunteers, with an age range of 20–30, were measured. The EAC volume was measured using three different methods: tympanometry, water injection, and HRCT. Two dimensional image slices of the EAC, in vivo, were obtained from the raw HRCT data. Each 2D CT image slice was composed of 512 × 512 pixels, with a 0.5 mm slice thickness, and a 0.175 × 0.175 × 0.5 mm3 voxel size. HRCT images were processed with Amira® software (Visage Imaging, Inc., San Diego, USA). Three-dimensional images of the EAC were reconstructed using an unconstrained smoothing mode. The resulting volume of the 3D model of the EAC was calculated using a voxel gate stacked tool. Using tympanometry, the mean measured EAC volume, averaged over all ears, was 766.66 mm3 (Standard Deviation, SD = 194.03 mm3). Using water injection, the mean measured EAC volume was 1102.77mm3 (SD = 121.60 mm3). Using HRCT, the mean measured EAC volume was 1082.22 mm3 (SD = 119.63 mm3). As evident from the SD values, variability was greater in the tympanometry group than in the water injection and HRCT groups. This study successfully developed a new technique to measure the EAC volume using HRCT imaging. This non-invasive technique for in vivo EAC volume measurement was less variable than tympanometry, and avoided the intrusive aspect of measurement by water injection. The technique allows effective, non-invasive assessment of the EAC volume pre-canalplasty, providing a predictor of EAC volume post-canalplasty.
A Low Damage Etching Process of Sub-100 nm Platinum Gate Line for III–V Metal–Oxide–Semiconductor Field-Effect Transistor Fabrication and the Optical Emission Spectrometry of the Inductively Coupled Plasma of SF6/C4F8
Authors: Li Xu , Zhou Haiping , Hill Richard J. W. , Holland Martin , Thayne Iain G.
Published: January 2012

This paper presents a low damage inductively coupled plasma (ICP) etching process to define sub-100 nm platinum gate lines for III–V metal–oxide–semiconductor field-effect transistors (MOSFETs) fabrication. In this process, a negative resist etching mask patterned by electron beam lithography is used to define the high resolution platinum features using a combination of SF6 and C4F8 etch gases. Systematic investigation of the impact of various etch conditions, such as coil and platen power, gas composition, chamber pressure on etch rate and profile, resulted in a controllable etching process. Optical emission spectra of the ICP plasma have been checked for better understanding the etching mechanism. Etch induced damage of the underlying device channel of the III–V MOSFET materials has been evaluated through monitoring the sheet resistance variation of the materials at room temperature, which showed the process does not significantly degrade the electrical properties of the underlying device channel under optimized conditions.
Deposition of SiO2 Thin Films on Polycarbonate by Atmospheric-Pressure Plasma
Authors: Kasuya Mikitoshi , Yasui Shinji , Noda Mikio
Published: January 2012

Low-temperature, atmospheric-pressure SiO2 thin film deposition was achieved using dielectric barrier discharge plasma with a high-voltage pulse. Experiments were conducted using diethoxydimethylsilane as the silicon source at different oxygen concentrations, gas flow rates, and deposition times. Hard, transparent thin-coated films were obtained at high oxygen concentrations because of the capture of carbon by oxygen during deposition. A deposition rate of 60 nm/min was achieved with the pulsed plasma at a duty ratio of 4%, gap length of 1 mm, and peak voltage of 13 kV without cooling or heating of the polycarbonate substrate. A usable SiO2 hard-coat film with a thickness of 1.6 µm and an indentation hardness of 1480 N/mm2 was obtained after a deposition time of 30 min in oxygen.
Enhanced Flyer Acceleration by Varying the Ion Beam–Plasma Interaction Field
Authors: Rungsirathana Thanat , Rungsetthaphat Vorathit , Azuma Shogo , Harada Nobuhiro
Published: January 2012

This paper presents a method for enhancing the ablation plasma production and the flyer velocity for flyer acceleration. A significant approach introduced is to optimize the interaction field of the ablation plasma and the Al target. To do so, it is acceptable to adjust the distance of ion beam irradiation. A one-dimensional hydrodynamic model is used in the calculations. The cube-interpolated propagation (CIP) method is used to describe the ablation plasma production and the acceleration mechanism. In the calculations, a single-pulsed ion beam with a total energy density of 120 J/cm2 is used. The interaction field (ion beam irradiation distance) that varies from 50 to 1000 µm is fixed for the calculations. At the interaction field of 50 µm, the flyer velocity of 2 km/s is calculated, while the value of 1.3 km/s is obtained at the distance of 400 µm. The results show that the closer the interaction field (distance of ion beam irradiation), the higher the flyer velocity obtained. In addition, the results reveal that the interaction field directly affects the amount of the ablation plasma produced and the flyer momentum.
Growth of ZnTe:O Thin Films by Oxygen-Plasma-Assisted Pulsed Laser Deposition
Authors: Pak Sang Woo , Suh Jooyoung , Lee Dong Uk , Kim Eun Kyu
Published: January 2012

We studied oxygen incorporation into ZnTe thin films with oxygen ambient and oxygen plasma during pulsed laser deposition (PLD). The ZnTe layers deposited by oxygen-plasma-assisted PLD under oxygen partial pressures showed the enhancement of visible absorption due to TeO
x
formation by oxygen incorporation, which was confirmed by X-ray photoelectron spectroscopy measurement. The ZnTe:O thin films grown under oxygen ambient and plasma produced an energy band structure at about 0.5–0.8 eV below the ZnTe band edge, indicating strong radiative properties. The ZnTe:O samples showed the formation of intermediate bands and p-type semiconducting characteristics, which will be useful for intermediate/defect band solar cells.
A Detailed Investigation of the Growth Conditions of Gallium Nitride Nanorods by Hydride Vapor Phase Epitaxy
Authors: Shin Min Jeong , Kim Min Ji , Jeon Hun Soo , Ahn Hyung Soo , Yi Sam Nyung , Huh Yoon , Yu Young-Moon , Sawaki Nobuhiko
Published: January 2012

We studied GaN nanorods grown by hydride vapour phase epitaxy processes to identify optimal growth conditions that yield nanorods appropriate for use in nanodevices. The growth temperature was varied over the range 625–670 °C, and the morphology of the samples changed with increasing growth temperature. GaN nanorods formed at growth temperatures of 645 °C on a Si(111) substrate. At a fixed growth temperature of 645 °C, the HCl:NH3 gas flow ratio was adjusted from 1:37 to 1:41. GaN nanorods with a small diameter of 26 nm formed at a HCl:NH3 ratio of 1:38. Individual GaN nanorods clearly grew along the axial direction, perpendicular to the substrate. Cathodoluminescence measurements at room temperature revealed a red shift as the acceleration energy was increased to 15 keV, possibly associated with the internal electric field.
Enhancement of Light Extraction Efficiency of InGaN Light-Emitting Diodes with an Air-Hole-Array Structure
Authors: Lin Chia-Feng , Huang Yu-Chieh , Chen Sy-Hann , Wang Guei-Miao , Yang Zong-Zhe
Published: January 2012

The truncated-conical air-hole (TAH) array structure of an InGaN light-emitting diode (LED) was fabricated on the mesa-edge region to increase the light extraction efficiency. The fabrication consisted of a dry process and a crystallographic wet etching process on the AlN buffer layer to form a truncated-conical air-hole array pattern. The light output power of the TAH-LED structure has a 55% enhancement compared with the conventional LED structure at 20 mA operation current. At 20 mA operation current, the forward voltage and peak electroluminescence wavelength of the TAH-LED were measured to be 3.09 V and 455.6 nm, respectively, similar to those of the conventional LED structure because the truncated-conical air-hole array pattern was fabricated around the mesa-edge region without affecting the current injection area with a top transparent contact layer.
Recent Progresses in GaN Power Rectifier
Authors: Alquier Daniel , Cayrel Frederic , Menard Olivier , Bazin Anne-Elisabeth , Yvon Arnaud , Collard Emmanuel
Published: January 2012

In this work, both “Schottky to Schottky” structure (STS) and pseudo-vertical Schottky barrier diode (pv-SBD) have been processed on GaN heteroepitaxially grown on sapphire or silicon by metal organic chemical vapor deposition (MOCVD) and characterized physically and electrically. Ni and Ti/Al were used to obtain respectively Schottky and Ohmic contacts using rapid thermal annealing (RTA). Adequate passivation steps and insertion of a resistive guard ring were also implemented in pv-SBD. The STS results, presented in this paper, evidence the impact of the substrate on the growth as well as all the progresses that have been done on GaN material quality. Furthermore, we demonstrate that high quality Schottky diodes can be obtained on GaN grown on sapphire by MOCVD. Indeed, ideality factors of 1.09 as well as a barrier height of 1.06 eV were obtained on pv-SBD devices that have a breakdown voltage over 600 V.
Growth and Device Properties of AlGaN/GaN High-Electron Mobility Transistors on a Diamond Substrate
Authors: Hirama Kazuyuki , Kasu Makoto , Taniyasu Yoshitaka
Published: January 2012

A crack-free c-plane AlGaN/GaN heterostructure was grown on a diamond (111) substrate by using an AlN/GaN multi-buffer layer. We found that in the AlGaN/GaN heterostructure, the GaN layer was coherently grown on the AlN/GaN multi-buffer layer. The a-lattice constant of strain-free GaN is longer than the average a-lattice constant of the AlN/GaN multi-buffer layer. Therefore, compressive strain is induced in the GaN layer of the AlGaN/GaN heterostructure. The compressive strain compensates for the tensile strain induced by the diamond substrate, which makes the AlGaN/GaN heterostructure free of cracks. AlGaN/GaN high-electron mobility transistors (HEMTs) fabricated on diamond substrates show the maximum drain current of 275 mA/mm, transconductance of 60 mS/mm, and clear pinch-off characteristics for a gate length of 6 µm. The low thermal resistance of the AlGaN/GaN HEMTs on the diamond is demonstrated.
Influence of Pulse Rising Time on Plasma Irradiation Effect
Authors: Yabuuchi Takahiro , Yasui Shinji
Published: January 2012

Plasma irradiation experiments were performed under atmospheric pressure in N2using two pulse power supplies with different pulse rising times, and the irradiation effect on a polycarbonate surface was examined. When investigating the effect of the pulse rising time on the contact angle, it was found that a short irradiation time of 5 s had a significant influence on the contact angle and that a larger decrease in the contact angle was observed with a fast-rising pulse. On the Basis of optical emission spectrometry of the plasma and a surface free energy analysis, the decrease in the contact angle was considered to be the result of the introduction of a large amount of hydrophilic groups on the surface. On the other hand, the effect of the plasma irradiation on the contact angle was not very different with a longer irradiation time of 5 min.
Effects of Dispersoids on Wear Behavior of Cu-Based Nanocomposite Containing SiO2 Nanoparticles
Authors: Sato Hisashi , Miura-Fujiwara Eri , Watanabe Yoshimi
Published: January 2012

Solid particles in discontinuous reinforcement metal matrix composites (DRMMCs) drastically improve their strength. Since the strength of DRMMCs is improved by the Orowan mechanism, smaller particles, such as nanoparticles, are effective as dispersoids. In this study, the effects of nanoparticles on the sliding wear behavior of DRMMCs are investigated using Cu-based composites containing 0.6, 1.2, and 1.7 vol % SiO2 particles. Wear resistance of the Cu–SiO2 composite is improved by increasing the volume fraction of SiO2 particles. Moreover, the amount of wear for the Cu–SiO2 composites increases with increasing sliding distance and then becomes saturated beyond about 1000 m. Vickers hardness for all specimens becomes the same regardless of the volume fraction of SiO2 particles as the sliding distance increases. This behavior can be explained by the work-hardening rate of the Cu matrix and the critical hardness for adhesion with a counter-material. It is found that nanoparticles in DRMMCs improve wear resistance by increasing the work-hardening rate of the metal matrix.
Evaluation of Off-State Current Characteristics of Transistor Using Oxide Semiconductor Material, Indium–Gallium–Zinc Oxide
Authors: Kato Kiyoshi , Shionoiri Yutaka , Sekine Yusuke , Furutani Kazuma , Hatano Takehisa , Aoki Taro , Sasaki Miyuki , Tomatsu Hiroyuki , Koyama Jun , Yamazaki Sunpei
Published: January 2012

We measured a significantly low off-state current (135 yA/µm at 85 °C) of a metal oxide semiconductor (MOS) transistor using indium–gallium–zinc oxide (IGZO), which is an oxide semiconductor material. Note that “y” is 10-24. A transistor in which the hydrogen concentration in an IGZO film is lowered (5×1019 cm-3 or lower) was used. To estimate the minute current accurately, we established a measurement method in which changes in the amount of electrical charge are measured for a long time. Such extremely low off-state current characteristics show promise for new applications of IGZO transistors in memories.
Extraction of Electron Band Mobility in Amorphous Silicon Thin-Film Transistors
Authors: Lee Jaehong , Jang Seunghyun , Lee Jaeho , Jung Keum-Dong , Park Mun-Soo , Yoo Moon-Hyun , Shin Hyungcheol
Published: January 2012

In this paper, extraction method of electron band mobility in amorphous silicon thin-film transistor (a-Si TFT) is presented. First, we propose the mobility model considering the traps of amorphous silicon and the vertical field dependent mobility degradation. Then we calculate the ratio of effective mobility to band mobility by considering the traps. After that, the vertical field dependent mobility degradation is applied to the model using fitting parameters. Through this process, 13 cm2 V-1 s-1 of band mobility is extracted in our devices. Experimentally extracted electron band mobility of a-Si TFTs would be useful to technology computer aided design (TCAD) and simulation program with integrated circuit emphasis (SPICE).
Surface Relief Formation in Azobenzene-Containing Polymers Using 325 nm Holography
Authors: Nishioka Emi , Kondo Mizuho , Emoto Akira , Ono Hiroshi , Kawatsuki Nobuhiro
Published: January 2012

Surface relief (SR) formation in polymethacrylate films with azobenzene side groups was investigated via a holographic method using 325 nm He–Cd laser, which generated stable cis isomers. Because the azobenzene molecules underwent both photoinduced reorientation and photoisomerization according to the polarization and intensity distribution of the interference beams, formation of the SR structure depended on both the exposure energy and polarization distribution. For intensity holography, both the photogenerated cis isomer distribution and polarization direction of the exposed beams played important roles in SR formation, which accompanied the molecularly reoriented SR structure. For polarization holography, a small SR structure accompanied the periodical molecular orientation in the initial stage of polarization holography due to uniform distribution of cis isomer. However, a SR structure larger than that generated by intensity holography was produced in the photostationary state.
Edge States of Bi Nanoribbons on Bi Substrates: First-Principles Density Functional Study
Authors: Kotaka Hiroki , Ishii Fumiyuki , Saito Mineo , Nagao Tadaaki , Yaginuma Shin
Published: January 2012

By using fully relativistic first-principles calculations, we study edge states of the Bi(001) nanoribbons. We find that freestanding zigzag bismuth nanoribbons (ZBNRs) have two spin degenerate bands around the Fermi energy, whose wave functions are localized at the edges. The wave functions are sharply localized at the edges at the zone boundary and become delocalized as the wave number decreases. In the case of the ZBNR on Bi substrates, the inversion symmetry is broken. As a result, the spin degenerate bands split and thus the density of states near the Fermi level has broad distributions; therefore, the electronic structures are expected to be stabilized. Because of the edge state near the Fermi energy, conduction along the edge lines is expected. However, the topological insulator predicted in the case of the freestanding ZBNR is not achieved in the case of the ZBNR on Bi substrates.
Numerical Simulation of Direct Current Glow Discharge in Air with Experimental Validation
Authors: He Wei , Liu Xing-Hua , Yang Fan , Wang Hong-Yu , Liao Rui-Jin , Xiao Han-Guang
Published: January 2012

An improved self-consistent, multicomponent, and two-dimensional plasma model for simulating low-pressure air glow discharge is presented. In the model, both the plasma hydrodynamics model and chemical model are considered, which include 12 species and 27 reactions. The discharge voltage–current characteristics and spatial profiles of electron temperature predicted by the model are in good agreement with experimental measurements. On the basis of the validated model, the characteristics of plasma evolution are investigated in detail. The simulation results show that the electron impact ionization reaction of N2shows the highest rate for electron production. N2+and O2+are the dominant positive ions, and N2+is smaller in amount on density than O2+at about one order of magnitude. The production rate of N2+is greater than that of O2+in the entire discharge process. This indicates that the positive ions and electrons play a prominent role in determining the characteristics of plasma. With time progresses, the conductive current density increases at the cathode, but decreases at the anode. Moreover, the conductive current density at the cathode is much smaller than that at the anode. It is shown that the presented developed plasma model can provide valuable insights into the physical mechanisms of low-pressure air glow discharge, and suggests ways to optimize practical engineering.
Effect of Process Parameters on Particle Removal Efficiency in Poly(vinyl alcohol) Brush Scrubber Cleaning
Authors: An Joonho , Lee Hyunseop , Kim Hyoungjae , Jeong Haedo
Published: January 2012

Wafer cleaning is one of the most critical processes in the semiconductor device manufacturing. Poly(vinyl alcohol) (PVA) brush scrubber cleaning is much attractive when compared with traditional wet-batch cleaning which causes the cross-contamination among the wafers in a bath and environmental issues with huge amount of chemical and deionized water (DIW) usages. The mechanical forces generated from PVA brush contact can remove the particles on a wafer surface under low concentration of chemical solution without cross-contamination. In this research, we monitored the change of the dynamic forces including normal and friction force generated by PVA brush contacts during cleaning process, and also investigated the effects of scrubbing conditions of PVA brush overlap and velocity, and the surface tension (low- or high-hydrophilic) of the wafer on the particle removal efficiency. The results show that the driving mechanism to remove the particle on a wafer surface can be changed by the PVA brush overlap and velocity condition such as the hydrodynamic drag force in the brush soft contact condition and friction force in the brush hard contact condition. The particle removal efficiency is higher under the low-hydrophilic surface having a low surface tension compared to high-hydrophilic surface.
Optoelectronic Mixing in Electroabsorption Waveguides under Very High Optical Power
Authors: Shin Dong-Soo , Yu Paul K. L.
Published: January 2012

We examine the performance of the electroabsorption (EA) mixer at high optical power. It is shown that the EA mixer can theoretically achieve an external conversion loss of ∼0 dB for waveguides that can handle very high optical power. The analysis is consistent with data deduced from prior experiments.
Current-Induced Magnetization Switching in Fe3Si/FeSi2 Artificial Lattices
Authors: Sakai Ken-ichiro , Sonoda Takayuki , Hirakawa Shin-ichi , Takeda Kaoru , Yoshitake Tsuyoshi
Published: January 2012

Current-induced magnetization switching in Fe3Si/FeSi2 artificial lattices, wherein ferromagnetic Fe3Si layers were antiferromagnetically coupled, was studied in a current perpendicular to plane geometry. While the electrical resistance–injected current (R–I) curve exhibited a clear hysteresis loop under zero magnetic field, the hysteresis loop in the curve disappeared under magnetic fields larger than the saturation magnetic field. This implies that the interlayer coupling was altered from antiferromagnetic to ferromagnetic by the current injection under zero magnetic field; on the other hand, under the magnetic fields, the coupling was fixed to be ferromagnetic regardless of the current injection.
Expression of Na+-d-glucose cotransporter SGLT2 in rodents is kidney-specific and exhibits sex and species differences
Authors: Sabolić Ivan , Vrhovac Ivana , Eror Daniela Balen , Gerasimova Maria , Rose Michael , Breljak Davorka , Ljubojević Marija , Brzica Hrvoje , Sebastiani Anne , Thal Serge C. , Sauvant Christoph , Kipp Helmut , Vallon Volker , Koepsell Hermann
Published: January 2012

With a novel antibody against the rat Na+-d-glucose cotransporter SGLT2 (rSGLT2-Ab), which does not cross-react with rSGLT1 or rSGLT3, the ∼75-kDa rSGLT2 protein was localized to the brush-border membrane (BBM) of the renal proximal tubule S1 and S2 segments (S1 > S2) with female-dominant expression in adult rats, whereas rSglt2 mRNA expression was similar in both sexes. Castration of adult males increased the abundance of rSGLT2 protein; this increase was further enhanced by estradiol and prevented by testosterone treatment. In the renal BBM vesicles, the rSGLT1-independent uptake of [14C]-α-methyl-d-glucopyranoside was similar in females and males, suggesting functional contribution of another Na+-d-glucose cotransporter to glucose reabsorption. Since immunoreactivity of rSGLT2-Ab could not be detected with certainty in rat extrarenal organs, the SGLT2 protein was immunocharacterized with the same antibody in wild-type (WT) mice, with SGLT2-deficient ( Sglt2 knockout) mice as negative control. In WT mice, renal localization of mSGLT2 protein was similar to that in rats, whereas in extrarenal organs neither mSGLT2 protein nor mSglt2 mRNA expression was detected. At variance to the findings in rats, the abundance of mSGLT2 protein in the mouse kidneys was male dominant, whereas the expression of mSglt2 mRNA was female dominant. Our results indicate that in rodents the expression of SGLT2 is kidney-specific and point to distinct sex and species differences in SGLT2 protein expression that cannot be explained by differences in mRNA.
Dyspnea-pain counterirritation induced by inspiratory threshold loading: a laser-evoked potentials study
Authors: Bouvier Guillaume , Laviolette Louis , Kindler Felix , Naccache Lionel , Mouraux André , Similowski Thomas , Morélot-Panzini Capucine
Published: January 2012

Background: experimentally induced dyspnea of the work/effort type inhibits, in a top-down manner, the spinal transmission of nociceptive inputs (dyspnea-pain counterirritation). Previous studies have demonstrated that this inhibition can be assessed by measuring the nociceptive flexion reflex (RIII). However, its clinical application is limited because of the strong discomfort associated with the electrical stimuli required to elicit the RIII reflex. Study objectives: we examined whether the dyspnea-pain counterirritation phenomenon can be evaluated by measuring the effect of work/effort type dyspnea on the magnitude of laser-evoked brain potentials (LEPs). Methods: 10 normal male volunteers were studied (age: 19–30 years). LEPs were elicited using a CO2 laser stimulator delivering 10- to 15-ms stimuli of 6 ± 0.7 W over a 12.5 mm2 area. The EEG was recorded using nine scalp channels. Non-nociceptive somatosensory-evoked potentials (SEPs) served as control. LEPs and SEPs were recorded before, during, and after 10 min of experimentally induced dyspnea [inspiratory threshold loading (ITL)]. Results: pain caused by the nociceptive laser stimulus was mild. ITL consistently induced dyspnea, mostly of the “excessive effort” type. Amplitude of the N2-P2 wave of LEPs decreased by 37.6 ± 13.8% during ITL and was significantly correlated with the intensity of dyspnea [ r = 0.66, CI 95% (0.08–0.92, P = 0.0319)]. In contrast, ITL had no effect on the magnitude of non-nociceptive SEPs. Discussion: experimentally induced dyspnea of the work/effort type reduces the magnitude of LEPs. This reduction correlates with the intensity of dyspnea. The recording of LEPs could constitute a clinically applicable approach to assess the dyspnea-pain counterirritation phenomenon in patients.
Regular and moderate exercise before experimental sepsis reduces the risk of lung and distal organ injury
Authors: de Araújo Carla C. , Silva Johnatas D. , Samary Cynthia S. , Guimarães Isabela H. , Marques Patrícia S. , Oliveira Gisele P. , do Carmo Luana G. R. R. , Goldenberg Regina C. , Bakker-Abreu Ilka , Diaz Bruno L. , Rocha Nazareth N. , Capelozzi Vera L. , Pelosi Paolo , Rocco Patricia R. M.
Published: January 2012

Physical activity modulates inflammation and immune response in both normal and pathologic conditions. We investigated whether regular and moderate exercise before the induction of experimental sepsis reduces the risk of lung and distal organ injury and survival. One hundred twenty-four BALB/c mice were randomly assigned to two groups: sedentary (S) and trained (T). Animals in T group ran on a motorized treadmill, at moderate intensity, 5% grade, 30 min/day, 3 times a week for 8 wk. Cardiac adaptation to exercise was evaluated using echocardiography. Systolic volume and left ventricular mass were increased in T compared with S group. Both T and S groups were further randomized either to sepsis induced by cecal ligation and puncture surgery (CLP) or sham operation (control). After 24 h, lung mechanics and histology, the degree of cell apoptosis in lung, heart, kidney, liver, and small intestine villi, and interleukin (IL)-6, KC (IL-8 murine functional homolog), IL-1β, IL-10, and number of cells in bronchoalveolar lavage (BALF) and peritoneal lavage (PLF) fluids as well as plasma were measured. In CLP, T compared with S groups showed: 1) improvement in survival; 2) reduced lung static elastance, alveolar collapse, collagen and elastic fiber content, number of neutrophils in BALF, PLF, and plasma, as well as lung and distal organ cell apoptosis; and 3) increased IL-10 in BALF and plasma, with reduced IL-6, KC, and IL-1β in PLF. In conclusion, regular and moderate exercise before the induction of sepsis reduced the risk of lung and distal organ damage, thus increasing survival.
Elucidating Prognosis and Biology of Breast Cancer Arising in Young Women Using Gene Expression Profiling
Authors: Azim Hatem A. , Michiels Stefan , Bedard Philippe L. , Singhal Sandeep K. , Criscitiello Carmen , Ignatiadis Michail , Haibe-Kains Benjamin , Piccart Martine J. , Sotiriou Christos , Loi Sherene
Published: January 2012

Purpose: Breast cancer in young women is associated with poor prognosis. We aimed to define the role of gene expression signatures in predicting prognosis in young women and to understand biological differences according to age.

Experimental Design: Patients were assigned to molecular subtypes [estrogen receptor (ER)+/HER2−; HER2+, ER−/HER2−)] using a three-gene classifier. We evaluated whether previously published proliferation, stroma, and immune-related gene signatures added prognostic information to Adjuvant! online and tested their interaction with age in a Cox model for relapse-free survival (RFS). Furthermore, we evaluated the association between candidate age-related genes or gene sets with age in an adjusted linear regression model.

Results: A total of 3,522 patients (20 data sets) were eligible. Patients aged 40 years or less had a higher proportion of ER−/HER2− tumors (P < 0.0001) and were associated with poorer RFS after adjustment for breast cancer subtype, tumor size, nodal status, and histologic grade and stratification for data set and treatment modality (HR = 1.34, 95% CI = 1.10–1.63, P = 0.004). The proliferation gene signatures showed no significant interaction with age in ER+/HER2− tumors after adjustment for Adjuvant! online. Further analyses suggested that breast cancer in the young is enriched with processes related to immature mammary epithelial cells (luminal progenitors, mammary stem, c-kit, RANKL) and growth factor signaling in two independent cohorts (n = 1,188 and 2,334).

Conclusions: Proliferation-related prognostic gene signatures can aid treatment decision-making for young women. However, breast cancer arising at a young age seems to be biologically distinct beyond subtype distribution. Separate therapeutic approaches such as targeting RANKL or mammary stem cells could therefore be needed. Clin Cancer Res; 18(5); 1341–51. ©2012 AACR.
Human Prostate Cancer in a Clinically Relevant Xenograft Mouse Model: Identification of β(1,6)-Branched Oligosaccharides as a Marker of Tumor Progression
Authors: Lange Tobias , Ullrich Sebastian , Müller Imke , Nentwich Michael F. , Stübke Katrin , Feldhaus Susanne , Knies Christine , Hellwinkel Olaf J.C. , Vessella Robert L. , Abramjuk Claudia , Anders Mario , Schröder-Schwarz Jennifer , Schlomm Thorsten , Huland Hartwig , Sauter Guido , Schumacher Udo
Published: January 2012

Purpose: To establish xenograft mouse models of metastatic and nonmetastatic human prostate cancer and to apply these models to the search for aberrant glycosylation patterns associated with tumor progression in vivo and in patients.

Experimental Design: Prostate cancer cells (LNCaP, PC-3, LuCaP 23.1, and DU-145) were xenografted subcutaneously into immunodeficient pfp−/−/rag2−/− mice. Tumor growth and metastasis formation were quantified and as altered glycosylation patterns have been associated with metastasis formation in several other malignancies, prostate cancer cells were profiled by a quantitative real-time PCR (qRT-PCR) glycosylation array and compared with normal human prostate cells. The activity of upregulated glycosyltransferases was analyzed by their sugar residues end products using lectin histochemistry on primary tumors and metastases in the animal experiments and on 2,085 clinical samples.

Results: PC-3 cells produced the largest number of spontaneous lung metastases, followed by LNCaP and LuCaP 23.1, whereas DU-145 was nonmetastatic. qRT-PCR revealed an upregulation of β1,6-N-acetylglucosaminyltransferase-5b (Mgat5b) in all prostate cancer cell lines. Mgat5b products [β(1,6)-branched oligosaccharides] were predominantly detectable in metastatic xenografts as shown by increased binding of Phaseolus vulgaris leukoagglutinin (PHA-L). The percentage of prostate cancer patients who were PHA-L positive was 86.5. PHA-L intensity correlated with serum prostate-specific antigen and a cytoplasmic staining negatively affected disease-free survival.

Conclusion: We show a novel xenograft mouse model for human prostate cancer respecting the complete metastatic cascade. Specific glycosylation patterns reveal Mgat5b products as relevant markers of both metastatic competence in mice and disease-free survival in patients. This is the first description of Mgat5b in prostate cancer indicating a significant biologic importance of β(1,6)-branched oligosaccharides for prostate cancer progression. Clin Cancer Res; 18(5); 1364–73. ©2012 AACR.
Galiximab Signals B-NHL Cells and Inhibits the Activities of NF-κB–Induced YY1- and Snail-Resistant Factors: Mechanism of Sensitization to Apoptosis by Chemoimmunotherapeutic Drugs
Authors: Martinez-Paniagua Melisa A. , Vega Mario I. , Huerta-Yepez Sara , Baritaki Stavroula , Vega Gabriel G. , Hariharan Kandasamy , Bonavida Benjamin
Published: January 2012

Galiximab (anti-CD80 monoclonal antibody) is a primatized (human IgG1 constant regions and cynomologus macaque variable regions) monoclonal antibody that is currently in clinical trials. Galiximab inhibits tumor cell proliferation through possibly cell signaling–mediated effects. Thus, we hypothesized that galiximab may signal the tumor cells and modify intracellular survival/antiapoptotic pathways such as the NF-κB pathway. This hypothesis was tested using various CD80+ Burkitt B-NHL (non–Hodgkin lymphomas) cell lines as models. Treatment of B-NHL cells with galiximab (25–100 μg/mL) resulted in significant inhibition of NF-κB activity and its target resistant factors such as YY1, Snail, and Bcl-2/Bcl-XL. Treatment of B-NHL cells with galiximab sensitized the tumor cells to both cis-diamminedichloroplatinum(II) (CDDP)- and TRAIL-induced apoptosis. The important roles of YY1- and Snail-induced inhibition by galiximab in the sensitization to CCDP and TRAIL were corroborated following transfection of Raji cells with YY1 or Snail short interfering RNA. The transfected cells were shown to become sensitive to both CCDP- and TRAIL-induced apoptosis in the absence of galiximab. Furthermore, knockdown of YY1 or Snail inhibited Bcl-XL. The involvement of Bcl-XL inhibition in sensitization was corroborated by the use of the pan-Bcl-2 inhibitor 2MAM-3 whereby the treated cells were sensitive to both CDDP- and TRAIL-induced apoptosis. These findings show that galiximab inhibits the NF-κB/Snail/YY1/Bcl-XL circuit that regulates drug resistance in B-NHL and in combination with cytotoxic drugs results in apoptosis. The findings also support the therapeutic application of the combination of galiximab and cytotoxic drugs in the treatment of drug-resistant CD80-positive B-cell malignancies. Mol Cancer Ther; 11(3); 572–81. ©2012 AACR.