bluuebunny/crossref_metadata_2025 huggingface dataset:
TYPE-II SiGe/Si MQWS (MULTI-QUANTUM WELLS) AND SELF-ORGANIZED Ge/Si ISLANDS GROWN BY UHV/CVD SYSTEM
Authors: YU JINZHONG , HUANG CHANGJUN , CHENG BUWEN , ZUO YUHUA , LUO LIPING , WANG QIMING
Published: December 2002

Type-II SiGe/Si MQWs (Multi-Quantum Wells) and Self-Organized Ge/Si Islands were successfully grown by a homemade ultra-high vacuum/chemical vapor deposition (UHV/CVD) system. Growth characteristics and PL (photoluminescence) spectra at different temperature were measured. It demonstrated that some accumulation of carriers in the islands results in the increase of the integrated PL intensity of island-related at a certain temperature range.
ELECTRICAL PROPERTIES OF Si1-X-YGeXCY FILMS GROWN BY ION IMPLANTATION AND SOLID PHASE EPITAXY
Authors: LIU XUEQIN , ZHEN CONGMIAN , WANG YINYUE , ZHANG JING , PU YUEJIAO , GUO YONGPING
Published: December 2002

Si 0.875-y Ge 0.125 C y ternary alloy films were grown on Si by ion implantation of C into Si 0.875 Ge 0.125 layers and subsequent solid phase epitaxy. It was shown that C atoms were nearly incorporated into substitutional sites and no SiC was formed in the SiGeC films by optimal two-step annealing. There is a prominent effect of C contents on carrier transport properties. Compared with strained Si 0.875 Ge 0.125 film, enhanced Hall mobility has been obtained in partially and fully strain compensated Si 0.875-y Ge 0.125 C y layer due to the reduction of lattice strain.
EFFECTS OF Si AND Er CONCENTRATION ON 1.54 μm PHOTOLUMINESCENCE FROM SILICA-BASED THIN FILMS
Authors: XIAO ZHISONG , XU FEI , CHENG GUOAN , ZHANG TONGHE , WONG S. P.
Published: December 2002

Erbium doped SiO 2 thin films containing Si nanocrystals were fabricated by Si and Er dual implantation into SiO 2 using a metal vapor vacuum arc (MEVVA) ion source. Photoluminescence (PL) intensity was strongly enhanced by the incorporation of nanocrystalline Si (nc-Si) in the SiO 2 films. For samples implanted with a fixed Er dose, there is an optimum Si dose to achieve a maximum 1.54 μm PL peak intensity, and likewise for samples implanted with a fixed Si dose, there is an optimum Er dose to achieve a maximum PL intensity. These results were discussed in terms of energy transfer mechanisms between the photogenerated carriers in the nc-Si and Er ions in the SiO 2 matrix.
X-RAY DIFFRACTION AND RAMAN STUDIES OF RF SPUTTERED POLYCRYSTALLINE SILICON GERMANIUM FILMS
Authors: LEOY C. C. , CHOI W. K. , WONG K. L. , WONG K. M. , OSIPOWICZ T. , RONG J.
Published: December 2002

Polycrystalline silicon germanium ( Si 1-x Ge x ) films were characterized using x-ray diffraction (XRD) and Raman spectroscopy techniques. The XRD results show that our films consist of Si 1-x Ge x alloy with no cluster of Ge or a Ge rich material embedded in a Si matrix. Comparison of the XRD results of RTA and furnace annealed samples for the same annealing conditions reveal that the latter allow for faster formation of the (200) and (311) crystal planes. Raman spectroscopy results indicate that our films were strain free.
HETEROEPITAXIAL GROWTH OF NOVEL SOI MATERIAL Si/γ-Al2O3/Si
Authors: WANG QI-YUAN , TAN LI-WEN , WANG JUN , YU YUAN-HUAN , LIN LAN-YING
Published: December 2002

In this paper, we report the fabrication of Si-based double hetero-epitaxial SOI materials Si /γ- Al 2 O 3/ Si . First, single crystalline γ- Al 2 O 3(100) insulator films were grown epitaxially on Si(100) by LPCVD, and then, Si(100) epitaxial films were grown on γ- Al 2 O 3(100)/ Si (100) epi-substrates using a CVD method similar to silicon on sapphire (SOS) epitaxial growth. The Si /γ- Al 2 O 3(100)/ Si (100) SOI materials are characterized in detail by RHEED, XRD and AES techniques. The results demonstrate that the device-quality novel SOI materials Si /γ- Al 2 O 3(100)/ Si (100) has been fabricated successfully and can be used for application of MOS device.
FORMATION OF OXYGEN-FREE GADOLINIUM SILICIDE LAYER BY ION IMPLANTATION AND PULSED EXCIMER LASER IRRADIATION
Authors: HE DEYAN , WANG WENWU , JIA HAIJUN , XIE ERQING
Published: December 2002

Buried gadolinium silicide layer was prepared by ion implantation of Gd into n-type Si (100) wafer. It was shown that GdSi 2 grains have been formed during Gd + implantation. An oxygen-free continuous layer of (112) oriented GdSi 2 was obtained after irradiating the sample using a pulsed excimer laser. Comparing with conventional thermal annealing pulsed excimer laser irradiation at energy densities close to the threshold for melting Si surface layer could prepare oxygen-free GdSi 2 buried layer within a preferred region.
EFFECT OF REACTION GAS ON THE STRUCTURAL AND OPTICAL FEATURES OF NC-SI:H THIN FILMS PREPARED BY PECVD
Authors: SHIM J.-H. , HAN K.-H. , PARK M.-B. , CHO N. H.
Published: December 2002

Hydrogenated nano-crystalline silicon (nc-Si:H) thin films were prepared by plasma enhanced chemical vapor deposition (PECVD). The variation in the crystallinity, nano-structure and optical characteristics of the nc-Si:H films with deposition variables such as reaction gas, post-deposition heat-treatment and deposition time were investigated; the relationship between the optical nano-structural features of the nc-Si:H films was discussed. The intensity of the PL peak, observed at about ~ 480 nm region, increased with the amount of reaction gas as well as deposition time. On the other hand, PL peaks appear at ~ 580 nm region when the sample was annealed in vacuum, and the intensity of the peaks increased with increasing the annealing time. It's believed that radiative recombination occurred due to the defects of SiO x in the film.
CHARACTERIZATION OF CUBIC BORON NITRIDE THIN FILMS DEPOSITED BY RF SPUTTER
Authors: DENG JINXIANG , CHEN GUANGHUA , SONG XUEMEI
Published: December 2002

Cubic boron nitride (c-BN) thin films have been deposited on Si substrates by radio frequency sputter. Sputtering target was hot pressed hexagonal boron nitride of 4N purity. Sputtering gas was the mixture of nitrogen and argon. During depositing c-BN thin films, substrates were biased by dc voltage negatively with respect to ground. By optimizing the deposition conditions, the boron nitride (BN) films containing a large amount of cubic phase were obtained. The samples were characterized with Fourier transformation infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). According to FTIR, the cubic phase content of c-BN thin films was evaluated to be 92. The B/N ratio was estimated to be approximately 1 from XPS. The AFM shows that the c-BN thin films delaminated from Si substrates obviously.
SELF-ASSEMBLED Ge-DOTS FOR Si SOLAR CELLS
Authors: PRESTING H. , KONLE J. , KIBBEL H.
Published: December 2002

Silicon solar cells with embedded germanium (Ge) layers deposited as 3-dimensional islands in the Stranski-Krastanov growth mode have been grown by molecular beam epitaxy (MBE) to enhance the efficiency of Si thin film solar cells. The Ge-layers increase the infrared absorption in the base of the cell to achieve higher photocurrent which should overcome the loss in the open circuit voltage due to incorporation of a smaller bandgap material in the heterostructure. Up to 75 layers of Ge, each about 8 monolayers (ML) thick, separated by Si-spacer layers (9-18nm) have been deposited at rather elevated temperatures (700°C) on a standard 10Ωcm p-type Si-substrate. Island densities of 1011 cm -2 have been achieved by use of antimony (Sb) as surfactant. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to characterize the growth of Ge-islands under variuos growth conditions. Photocurrent measurements exhibit a higher photo-response in the infrared regime but a lower open circuit voltage of the fabricated solar cells compared to a Si-reference cell.
IN-SITU DIAGNOSIS AND CONTROL OF CRYSTAL GROWTH PROCESS BY MEANS OF ELECTRIC POTENTIALS
Authors: TSVETKOV E. G. , TYURIKOV V. I.
Published: December 2002

The paper discussed a possibility of using new approaches for in-situ diagnosis growth processes of large crystals as well as solving some specific problems of controlling them. They are based on the current monitoring of changes in the differences of electric potential between growing crystals and crystallization medium. It is obvious that this monitoring reflects such important crystallization processes as accumulation of charge at the crystal interface and electric screening of it, growth of concentration of subphase formation at the interface (later, inclusions), current change in the mass crystallization rate, etc. This change in the rate suggests a new concept of automation of crystal growth processes, based on minimization of the difference in the current and initially predetermined change in Δϕ through inversely-related adjustment of the temperature of crystallization medium. We have experimentally substantiated the possibility of using various outer electric potentials for modification of processes in a double electric layer at the interface and extension of growth period under fairly favorable conditions. The system of low-temperature phase of barium metaborate crystal and molten solution as crystallization medium was taken for a model one.
TILT DEPENDENT PL AND FLUORESCENCE SPECTRA OFInGaAsP/In0.5(GaAl)0.5PQUANTUM WELL
Authors: WEI JIYONG , HUANG BAIBIAO , YU YONGQIN , ZHOU HAILONG , PAN JIAOQING , ZHANG XIAOYANG , QIN XIAOYAN , XIA WEI , WANG DUXIANG , YUE JINSHUN , REN ZHONGXIANG
Published: December 2002

By 532 nm laser pumped PL spectral and Xe pumped fluorescence spectral, characterized InGaAsP/In0.5( GaxAl1-x)0.5P quantum well on substrates 2°, 15° tilted to (110) the optical property dependence of substrates tilt. The PL wavelength varies from 755 nm of the quantum well on substrate of 2° to the 780 nm of the quantum well on substrate of 15°. From fluorescence excitation spectral to excite about 760 nm wavelength of quantum well, the absorption light peak wavelength is 508 nm in common, and has another absorption peak wavelength of 622 nm. Excited by 508 nm and 622 nm wavelength, the fluorescence spectral intensity of the 15° quantum well is about 300 and 104accordingly. Lifetime of charge recombination is about 1.26 ns for this material.
IN-SITU SPECTRAL ANALYSIS OF VERY HIGH FREQUENCY GLOW DISCHARGE (VHF-GD)
Authors: YANG HUIDONG , WU CHUNYA , XIONG SHAOZHENG , MAI YAOHUA , LI HONGBO , LI YAN , CHEN YOUSU , WANG ZONGBAN , ZHAO YING , GENG XINHUA
Published: December 2002

The intensities of SiH*, [Formula: see text] and H* of VHF-GD for depositing μc-Si:H were much higher than those of RF-GD for depositing a-Si:H. The SiH* intensity of VHF-GD became higher than its Si* intensity as the hydrogen dilution ratio decreased. The influences of the hydrogen dilution ratio on the plasma optical emission spectra also depended on the reaction pressure, the excitation power as well as the excitation frequency.
INTERFACIAL STRUCTURES OF Si3N4 on Si (100) & Si (111)
Authors: CHOU L. J. , HUANG M. L. , HSIEH J. Y. , CHUEH Y. L. , GWO S. , HSUEH C. C. , PAN SAM
Published: December 2002

The initial stages of NH 3 exposure on Si (100) & Si (111) at different substrate temperatures and post annealing in different ambient gases have been investigated. On the Si (100) surface, at 850°C and very high (~ 1050°C) temperatures, NH 3 dissociated and nitridized the Si interface. The degree of nitride crystallization has been enhanced at elevated temperature (~ 1050°C). The interfacial trapped density is lower at higher temperature. I-V measurements indicated that the electrical properties are improved as the substrate temperature is raised. The results were directly related to the better interfacial registry. For the Si(111) substrates, the trends are similar to Si(100), but are more prominent.
EPR INVESTIGATION OF Bi2O3-As2O3-MnO GLASSES
Authors: PETEANU M. , TODOR IOANA , ARDELEAN I.
Published: December 2002

Glasses of the system Bi 2 O 3· As 2 O 3 doped with MnO up to 20 mol% were studied by means of EPR. The distribution of Mn 2+ ions on different structural units of the matrix was studied as function of the MnO content of the glass. The revealed valence states of manganese ions and the interactions involving them are discussed.
INCOMMENSURATE CRYSTAL GROWTH BEHAVIOR IN STRONTIUM TITANATE GLASS CERAMIC SYSTEM
Authors: THAKUR O. P. , KUMAR DEVENDRA , PARKASH OM , PANDEY LAKSHMAN
Published: December 2002

Crystals with different faceting behavior were observed in the strontium titanate borosilicate glass ceramic system with a small amount of bismuth oxide addition and proper heat treatment schedule. These types of faceting morphology were generally observed in phase-separated glasses followed by heterogeneous nucleation. X-ray diffraction and electron microscopic techniques were used to characterize these samples. X-ray diffraction patterns for bulk and pulverized samples were observed to be readily different from each other. Peaks in the X-ray diffraction pattern for bulk samples can be indexed for icosahedral symmetry.
DNA Protection by PNA from Enzymatic Digestion for Mass-spectroscopic Genotyping
Authors: Ye Sheng , Liang Xingguo , Yamamoto Yoji , Komiyama Makoto
Published: December 2002

By treating single-stranded DNA with nuclease S1 in the presence of peptide nucleic acid (PNA), oligonucleotides of predetermined size were successfully obtained. Mass spectroscopy on these fragments concretely substantiated alteration of one nucleotide to another, if any, in the DNA.
Rhodium Complexes of 1,4-Disubstituted-1,2,3-butatrienes: Their Preparation and Reactivity
Authors: Suzuki Noriyuki , Fukuda Yoshiyuki , Kim Chae Eun , Takahara Hidemichi , Iwasaki Masakazu , Saburi Masahiko , Nishiura Masayoshi , Wakatsuki Yasuo
Published: December 2002

The 1,4-disubstituted butatrienes, (Z)-R-CH=C=C=CH-R (1, R = SiMe3, t-Bu), reacted with RhCl(PAr3)3 (Ar = Ph, p-tolyl) to give rhodium-(Z)-butatriene complexes 3. The butatrienes coordinated to Rh with the central double bond in an η2-fashion. (Z)-Butatrienes on 3 isomerized to (E)-form at 70 °C to afford (E)-butatriene complexes 4 with excellent E/Z ratios (E/Z = 97/3–99/1). The molecular structure of 4b (R = SiMe3, Ar = p-tolyl) was determined by X-ray diffraction analysis. Hydrosilation of 1 was catalyzed by rhodium complexes to give allenes as major products accompanied by 1,3-dienes as minor ones, which are results of 2,1-addition and 2,3-anti-addition of the silane.
Morphology Related to Phase Separation for the Mixed Monolayer of Fluorinated Comb Polymer and Hydrogenated Long-Chain Compound
Authors: Fujimori Atsuhiro , Nakahara Hiroo
Published: December 2002

From observations of the atomic and friction force microscopies, it has been found that the mixed monolayers of the comb polymer having the fluorocarbon side-chains and the hydrogenated amphiphile, exhibit a characteristic phase separation behavior at the micro- and mesoscopic resolutions. The regularity for molecular orientation in the mixed film was compared with that in the pure monolayer of the fluorinated comb polymer by using polarized NEXAFS spectroscopy.
Ruthenium Complex-catalyzed Oxidative Cyclization of 4-Penten-1-ols
Authors: Kondo Teruyuki , Tsunawaki Fumiaki , Sato Ryosuke , Ura Yasuyuki , Wada Kenji , Mitsudo Take-aki
Published: December 2002

Treatment of 2-phenyl-5-hexen-2-ol (1a) with Ru3(CO)12 catalyst and PPh3 ligand in the presence of allyl acetate and K2CO3 in toluene at 160 °C for 20 h under 5 atm of carbon monoxide gave the corresponding oxidative cyclization product, 2,5-dimethyl-2-phenyl-2,3-dihydrofuran (2a), in quantitative yield (>99%).
Electrophosphorescence from Tetrameric Copper (I)-Amide Cluster
Authors: Noto Mitsuharu , Goto Yasuyuki , Era Masanao
Published: December 2002

Green electrophosphorescence from a tetrameric copper (I)-amide cluster [CuN(Si(CH3)3)2]4 was successfully observed in the heterostructure device combined with organic carrier transport materials and the copper cluster (peak wavelength = 493 nm, and max. luminance = 400 cdm−2 at a current density of 177 mA cm−2 at a drive voltage of 22 V).
Preparation of Polymer Micropheres in TEOS under Static Condition
Authors: Wang Dongjun , Gu Chenbin , Zhou Yongguo , Wang Xinqiu , Zhen Zhen , Tang Fangqiong , Liu Xinhou
Published: December 2002

Well-defined PMMA microspheres have been synthesized in TEOS under static condition by one step, the formation and size control of the microspheres are discussed.
A Novel Route towards Iron- and Chromium-containing MCM-41 Materials through Melt-exchange of the Template
Authors: Bourlinos Athanasios B , Karakassides Michael A , Gournis Dimitrios , Georgakilas Vasilios , Moukarika Aliki
Published: December 2002

Solid state treatment of an MCM-41 hybrid with molten iron(III) and chromium(III) salts, afforded the corresponding metal-containing MCM-41 materials free of the organic template and with high metal contents and thermal stability.
Low-temperature Complete Combustion of Methane over CeO2-Promoted Pd/HZSM-5 Catalyst with Enhanced Activity and Stability
Authors: Shi Chun-Kai , Yang Le-Fu , Cai Jun-Xiu
Published: December 2002

High catalytic activity and thermal/hydrothermal stability in the course of the low-temperature methane combustion were characteristics of the Pd–Ce/HZSM-5 catalyst, which was easily prepared by an impregnation method.
Aniline-Hydroxylation Activity of a Flavin-linked βαβα-Type Polypeptide Packing an Iron Porphyrin
Authors: Tomizaki Kin-ya , Nishino Hidekazu , Arai Toru , Kato Tamaki , Nishino Norikazu
Published: December 2002

Polypeptide containing iron porphyrin and flavin showed aniline-hydroxylation activity in the presence of 1-benzyl-1,4-dihydronicotinamide and O2. The increased activity at pH 5.5 compared with that at pH 7.0 suggests that the dissociation of His from the iron porphyrin favored the hydroxylation.
Finding an ideal site for intraosseous infusion of the tibia: An anatomical study
Authors: Boon J.M. , Gorry D.L.A. , Meiring J.H.
Published: December 2002

Intraosseous infusion is a technique used for the administration of fluids to a hemodynamically shocked child in whom attempts to access the vascular system have been unsuccessful. Although few complications are seen, injury to the epiphyseal growth plate during the performance of this technique remains a serious problem. This study investigates the relationship between the site of insertion of the intraosseous needle and the epiphyseal growth plate, and the ease of needle insertion into various locations of the tibia in newborn infants. Fourteen newborn infant cadavers (28 tibias in total) were dissected after placement of four needles: 1) through the tibial tuberosity (Site A); 2) 10 mm distal to the tibial tuberosity (Site B); 3) 20 mm distal to the tibial tuberosity (Site C) and; 4) 10 mm proximal to the tibial tuberosity (Site D). Distances from the distal end of the epiphyseal growth plate were measured. A high number of needle placements at Site A were inserted into the epiphyseal growth plate. Most placements at Site B were between 10 and 16 mm from the epiphyseal growth plate on the right side and between 10 and 15 mm on the left side, and all were inserted without difficulty. Although far from the epiphyseal growth plate, most placements at Site C were very difficult to insert because of the thick cortical bone. All placements at Site D entered the epiphysis or the epiphysis and joint space of the knee. An insertion site of at least 10 mm distal to the tibial tuberosity is therefore recommended to avoid epiphyseal growth plate injury and ensure ease of insertion. Clin. Anat. 16:15–18, 2003. © 2002 Wiley‐Liss, Inc.
Eye movements and attention for behavioural animation
Authors: Gillies M. F. P. , Dodgson N. A.
Published: December 2002

This paper describes a simulation of attention behaviour aimed at computer‐animated characters. Attention is the focusing of a person's perception on a particular object. This is useful for computer animation as it determines which objects the character is aware of: information that can be used in the simulation of the character's behaviour in order to automatically animate the character. The simulation of attention also determines where the character is looking and so is used to produce gaze behaviour. Copyright © 2002 John Wiley & Sons, Ltd.
Modeling the Martian dust cycle 2. Multiannual radiatively active dust transport simulations
Authors: Newman Claire E. , Lewis Stephen R. , Read Peter L. , Forget François
Published: December 2002

Multiannual dust transport simulations have been performed using a Mars general circulation model containing a dust transport scheme which responds to changes in the atmospheric state. If the dust transport is “radiatively active,” the atmospheric state also responds to changes in the dust distribution. This paper examines the suspended dust distribution obtained using different lifting parameterizations, including an analysis of dust storms produced spontaneously during these simulations. The lifting mechanisms selected are lifting by (1) near‐surface wind stress and (2) convective vortices known as dust devils. Each mechanism is separated into two types of parameterization: threshold‐sensitive and ‐insensitive. The latter produce largely unrealistic annual dust cycles and storms, and no significant interannual variability. The threshold‐sensitive parameterizations produce more realistic annual and interannual behavior, as well as storms with similarities to observed events, thus providing insight into how real Martian dust storms may develop. Simulations for which dust devil lifting dominates are too dusty during northern summer. This suggests either that a removal mechanism (such as dust scavenging by water ice) reduces opacities at this time or that dust devils are not the primary mechanism for storm production. Simulations for which near‐surface wind stress lifting dominates produce the observed low opacities during northern spring/summer, yet appear unable to produce realistic global storms without storm decay being prevented by the occurrence of large‐scale positive feedbacks on further lifting. Simulated dust levels are generally linked closely to the seasonal state of the atmosphere, and no simulation produces the observed amount of interannual variability.
Exhumation of high‐pressure metamorphic rocks in a subduction channel: A numerical simulation
Authors: Gerya Taras V. , Stöckhert Bernhard , Perchuk Alexey L.
Published: December 2002

High‐pressure metamorphic rocks provide evidence that in subduction zones material can return from depths of more than 100 km to the surface. The pressure‐temperature paths recorded by these rocks are variable, mostly revealing cooling during decompression, while the time constraints are generally narrow and indicate that the exhumation rates can be on the order of plate velocities. As such, subduction cannot be considered as a single pass process; instead, return flow of a considerable portion of crustal and upper mantle material must be accounted for. Our numerical simulations provide insight into the self‐organizing large‐scale flow patterns and temperature field of subduction zones, primarily controlled by rheology, phase transformations, fluid budget, and heat transfer, which are all interrelated. They show the development of a subduction channel with forced return flow of low‐viscosity material and progressive widening by hydration of the mantle wedge. The large‐scale structures and the array of pressure‐temperature paths obtained by these simulations favorably compare to the record of natural rocks and the structure of high‐pressure metamorphic areas.
A DESIGNING OF HETEROJUNCTION STRUCTURE OF N-Si/Si1-xGex HEMT
Authors: HU YING , HAN QIANG , ZHOU XIAOHUA , HUANG YUNXIA , XU YULONG
Published: December 2002

One has discussed the principle and method of designing the heterojunction structure of n - Si/Si 1-x Ge x HEMT from the lattice match and the energy band discontinuity points, analysed and calculated the HEMT reported by K. Ismail and obtained 2DEG (two Dimension Electron Gas) density n s essentially according with the experiment data. Final the design of the heterojunction of K. Ismail's HEMT is improved to get a higher 2DEG density n s .
CORRELATION BETWEEN Er3+ EMISSION AND THE MICROSTRUCTURE OF A-SiOx:H FILMS
Authors: CHEN C. Y. , CHEN W. D. , SONG S. F. , HSU C. C.
Published: December 2002

Photoluminescence (PL) from Er-implanted hydrogenated amorphous silicon suboxide ( a - SiO X : H 〈 Er 〉( x <2.0)) films was measured. Two luminescence bands with maxima at λ ≅ 750 nm and λ ≅ 1.54μ m, ascribed to the a - SiO x : H intrinsic emission and Er 3+ emission, were observed. Peak intensities of the two bands follow the same trend as a function of annealing temperature from 300 to 1000°C. Micro-Raman results indicate that the a - SiO x : H < Er > films are a mixture of two phases, an amorphous SiO x matrix and amorphous silicon (a-Si) domains embedded there in. FTIR spectra confirm that hydrogen effusion from a - SiO x : H < Er > films occurs during annealing. Hydrogen effusion leads to a reconstruction of the microstructure of a-Si domains, thus having a strong influence on Er 3+ emission. Our study emphasizes the role of a-Si domains on Er 3+ emission in a - SiO x : H < Er > films.
HETEROEPITAXIAL GROWTH AND ANNEALING OF γ-AL2O3 THIN FILMS ON SILICON
Authors: TAN LIWEN , WANG JUN , WANG QIYUAN , YU YUANHUAN , LIN LANYING
Published: December 2002

The γ- Al 2 O 3 films were grown on Si (100) substrates using the sources of TMA ( Al ( CH 3)3) and O 2 by very low-pressure chemical vapor deposition (VLP-CVD). It has been found that the γ- Al 2 O 3 film has a mirror-like surface and the RMS was about 2.5nm. And the orientation relationship was γ- Al 2 O 3(100)/ Si (100). The thickness uniformity of γ- Al 2 O 3 films for 2-inch epi-wafer was less than 5%. The X-ray diffraction (XRD) and reflection high-energy electron diffraction (RHEED) results show that the crystalline quality of the film was improved after the film was annealed at 1000°C in O 2 atmosphere. The high-frequency C-V and leakage current of Al /γ- Al 2 O 3/ Si capacitor were also measured to verify the annealing effect of the film. The results show that the dielectric constant increased from 4 to 7 and the breakdown voltage for 65-nm-thick γ- Al 2 O 3 film on silicon increases from 17V to 53V.
AN ULTRAVIOLET PHOTODETECTOR BASED ON GaN/Si
Authors: YE ZHIZHEN , GU XING , HUANG JINGYUN , WANG YU , SHAO QINGHUI , ZHAO BINGHUI
Published: December 2002

Single crystalline GaN is grown on Si(111) by a vacuum reactive evaporation method. X-ray diffraction(XRD), scanning electron microscopy(SEM), photoluminescence measurement (PL), and Hall measurement results indicate that single crystalline wurtzite GaN film is grown on the microcrystalline GaN buffer layer on Si(111) substrate. The photoconductive ultraviolet photodetector with a metal-semiconductor-metal(MSM) structure is prepared on the unintentionally doped n-type GaN film and the properties of the detector are investigated. The detector has a peak photocurrent responsivity at 365nm and a abrupt cut-off curve. The responsivity increased with the increasing of bias voltage. The responsivity saturated when the bias voltage reached 7V. The response time was ms level under normal conditions and dropped with the increase of bias voltage before the bias voltage reached its saturation.
QUANTITATIVE STUDY OF SURFACE MORPHOLOGY BY ATOMIC FORCE MICROSCOPY
Authors: CHOI Y. , CHO N. I. , CHOE J. I.
Published: December 2002

Atomic force microscopy was applied to study the formation and growth mechanism of thin multilayers of chromium-molybdenum and chrome prepared by electro-pulse plating, respectively. The chromium-molybdenum and chrome layers were prepared using direct current density of 1.6 mA.mm -2 and pulse currents with on-off time from 5 to 2000 ms in the bath containing 300g l-1 of chromic acid and 75g l-1 ammonium molybdate, and 250g l-1 of chromic acid and 5g l-1 of sulfuric acid, respectively. The higher current density enhanced nucleation rate which resulted in refining grain size. The micro-hardness of the pulse plated chrome and chromium-molybdenum alloy layers increased with the duration of on-off time and pulse current density. The average surface roughness of chrome layer is increased with increasing on/off time ratio for a given peak current density and voltage because the growth and dissolution mainly occurs during on-time and off-time, respectively. However, the average surface roughness of chromium-molybdenum alloy layer is decreased with increasing on/off time ratio for a given peak current density and voltage because the alloying element in the layer.
Attitudes of Japanese Physicians Toward Terminal Dehydration: A Nationwide Survey
Authors: Morita Tatsuya , Shima Yasuo , Adachi Isamu
Published: December 2002

PURPOSE: To clarify physician attitudes toward terminal dehydration and identify the physician-related factors contributing to their attitudes.

METHODS: A cross-sectional survey of Japanese physicians with a self-reported questionnaire was used.

RESULTS: A total of 584 responses were analyzed (response rate, 53%). In the vignette of a gastric cancer patient with an estimated survival of 1 month and almost impossible oral intake due to intestinal obstruction, 50% chose intravenous hydration of 1,000 mL/d, while 24% selected more than 1,500 mL/d. For a lung cancer patient with cachexia, 58% chose 1,000 mL/d, while 26% selected no hydration or 500 mL. Multivariate analyses revealed that the physicians with more positive attitudes toward intravenous hydration were significantly less involved in end-of-life care, more likely to regard the physiologic requirement of fluid and nutrition as important in initiating intravenous hydration, more likely to believe that intravenous hydration is effective for symptom palliation, and more likely to believe that intravenous hydration is the minimum standard of care.

CONCLUSION: Physicians have considerably divergent attitudes toward intravenous hydration for terminally ill cancer patients. To resolve the discrepancy, the priority in hydration research should be to clarify the appropriate physiologic requirements of fluid and nutrition in dying patients, the effects of intravenous hydration on patient symptoms, and the reasons why physicians consider intravenous hydration to be the minimum standard of care.
Anomalous flexor of the little finger
Authors: Kobayashi N. , Saito S. , Wakisaka H. , Matsuda S.
Published: December 2002

We report an anomalous palmar muscle belly of the flexor digitorum superficialis muscle (FDS) in the right hand of an 80‐year‐old female cadaver. The muscle originated from the center of the volar surface of the flexor retinaculum and inserted onto the palmar aspect of the base of the middle phalanx of the little finger. Its tendon of insertion divided into two bands, a pattern typical of the FDS tendon, between which the tendon of flexor digitorum profundus muscle to the little finger passed. The tendon of the usual antebrachial FDS to the little finger was absent. The anomalous muscle belly was innervated by a branch from the median nerve. Clin. Anat. 16:40–43, 2003. © 2002 Wiley‐Liss, Inc.
Vascularity and neuroreceptors of the pes anserinus: Anatomic Study
Authors: Zaffagnini S. , Golanò P. , Farinas O. , Depasquale V. , Strocchi R. , Cortecchia S. , Marcacci M. , Visani A.
Published: December 2002

The primary aim of this work was to evaluate the neurovascular network of the pes anserinus (PA) at its tibial insertion because the PA is often used for anterior cruciate ligament (ACL) reconstruction. Four fresh cadaver knees were injected with India ink gelatin solution and the arteries that supply blood to the PA were identified; microscopic studies of vessels and nerve fibers were also performed. Superficial and deep branches of the inferior medial genicular artery contribute to an arterial arch that courses deep to the PA insertion. A widespread array of small vessels and nerve fibers penetrate the PA insertion and course along the length of the gracilis and semitendinosus tendons. Computer analysis revealed that the mean diameter of the vessels decreased from 2,201 μm at the insertion to 661 μm midway along the length of the tendon (mean tendon length = 17 cm; range = 13–21 cm); the cross‐sectional area of the vessels per histologic section decreased from 336.37–137.05 μm2. This study demonstrates that the PA insertion is well vascularized and richly innervated and that these morphological features continue along the length of the tendons. Clin. Anat. 16:19–24, 2003. © 2002 Wiley‐Liss, Inc.
An approximation algorithm for optimal consumption/investment problems
Authors: Das Sanjiv Ranjan , Sundaram Rangarajan K.
Published: December 2002

This article develops a simple approach to solving continuous‐time portfolio choice problems. Portfolio problems for which no closed‐form solutions are available may be handled by this technique, which substitutes the numerical solution of partial differential equations with a non‐linear numerical algorithm approximating the solution. This paper complements the wide literature in economics on the solution of dynamic problems in discrete time using projection methods. Our approach extends the approximation function to power forms, which are shown to fit finance type problems well. The algorithm is parsimonious, and is first illustrated by solving two basic examples, first, the standard Merton problem, and second, a jump‐diffusion problem. Then, we demonstrate that the model is easy to implement on a larger scale, by optimizing a portfolio of six stock indexes, and stochastic volatility driven by two correlated state variables. Copyright © 2002 John Wiley & Sons, Ltd.
Historical changes in lake ice‐out dates as indicators of climate change in New England, 1850–2000
Authors: Hodgkins Glenn A. , James Ivan C. , Huntington Thomas G.
Published: December 2002

Various studies have shown that changes over time in spring ice‐out dates can be used as indicators of climate change. Ice‐out dates from 29 lakes in New England (USA) with 64 to 163 years of record were assembled and analysed for this study. Ice‐out dates have become significantly earlier in New England since the 1800s. Changes in ice‐out dates between 1850 and 2000 were 9 days and 16 days in the northern/mountainous and southern regions of New England respectively. The changes in the ice‐out data over time were very consistent within each of the two regions of New England, and more consistent than four air‐temperature records in each region. The ice‐out dates of the two regions had a different response to changes in air temperature. The inferred late winter–early spring air‐temperature warming in both regions of New England since 1850, based on linear regression analysis, was about 1.5°C. Published in 2002 by John Wiley & Sons, Ltd.
Genetic and environmental influences on human psychological differences
Authors: Bouchard Thomas J. , McGue Matt
Published: December 2002

Psychological researchers typically distinguish five major domains of individual differences in human behavior: cognitive abilities, personality, social attitudes, psychological interests, and psychopathology (Lubinski, 2000). In this article we: discuss a number of methodological errors commonly found in research on human individual differences; introduce a broad framework for interpreting findings from contemporary behavioral genetic studies; briefly outline the basic quantitative methods used in human behavioral genetic research; review the major criticisms of behavior genetic designs, with particular emphasis on the twin and adoption methods; describe the major or dominant theoretical scheme in each domain; and review behavioral genetic findings in all five domains. We conclude that there is now strong evidence that virtually all individual psychological differences, when reliably measured, are moderately to substantially heritable. © 2003 Wiley Periodicals, Inc. J Neurobiol 54: 4–45, 2003
Phage‐display and correlated mutations identify an essential region of subdomain 1C involved in homodimerization of Escherichia coli FtsA
Authors: Carettoni Daniele , Gómez‐Puertas Paulino , Yim Lucía , Mingorance Jesús , Massidda Orietta , Vicente Miguel , Valencia Alfonso , Domenici Enrico , Anderluzzi Daniela
Published: December 2002

FtsA plays an essential role in Escherichia coli cell division and is nearly ubiquitous in eubacteria. Several evidences postulated the ability of FtsA to interact with other septation proteins and with itself. To investigate these binding properties, we screened a phage‐display library with FtsA. The isolated peptides defined a degenerate consensus sequence, which in turn displayed a striking similarity with residues 126–133 of FtsA itself. This result suggested that residues 126–133 were involved in homodimerization of FtsA. The hypothesis was supported by the analysis of correlated mutations, which identified a mutual relationship between a group of amino acids encompassing the ATP‐binding site and a set of residues immediately downstream to amino acids 126–133. This information was used to assemble a model of a FtsA homodimer, whose accuracy was confirmed by probing multiple alternative docking solutions. Moreover, a prediction of residues responsible for protein‐protein interaction validated the proposed model and confirmed once more the importance of residues 126–133 for homodimerization. To functionally characterize this region, we introduced a deletion in ftsA, where residues 126–133 were skipped. This mutant failed to complement conditional lethal alleles of ftsA, demonstrating that amino acids 126–133 play an essential role in E. coli. Proteins 2003;50:192–206. © 2002 Wiley‐Liss, Inc.
Predictive crystallization of ribonuclease A via rapid screening of osmotic second virial coefficients
Authors: Tessier Peter M. , Johnson Harvey R. , Pazhianur Rajesh , Berger Bryan W. , Prentice Jessica L. , Bahnson Brian J. , Sandler Stanley I. , Lenhoff Abraham M.
Published: December 2002

Important progress has been made in recent years toward developing a molecular‐level understanding of protein phase behavior in terms of the osmotic second virial coefficient, a thermodynamic parameter that characterizes pairwise protein interactions. Yet there has been little practical application of this knowledge to the field of protein crystallization, largely because of the difficult and time‐consuming nature of traditional techniques for characterizing protein interactions. Self‐interaction chromatography has recently been proposed as a highly efficient method for measuring the osmotic second virial coefficient. The utility of the technique is examined in this work by characterizing virial coefficients for ribonuclease A under 59 solution conditions using several crystallization additives, including PEG, sodium chloride, ammonium sulfate, and propanol. The virial coefficient measurements show some counterintuitive trends and shed light on the previous difficulties in crystallizing ribonuclease A. Crystallization experiments at the corresponding solution conditions were conducted by using ultracentrifugal crystallization. Using this methodology, ribonuclease A crystals were obtained under conditions for which the virial coefficients fell within the “crystallization slot.” Crystallographic characterization showed that the crystals diffract to high resolution. Metastable crystals were also obtained for conditions outside, but near, the “crystallization slot,” and they could also be frozen and used to collect structural information. Proteins 2003;50:303–311. © 2002 Wiley‐Liss, Inc.
The HI0073/HI0074 protein pair from Haemophilus influenzae is a member of a new nucleotidyltransferase family: Structure, sequence analyses, and solution studies
Authors: Lehmann Christopher , Lim Kap , Chalamasetty Vani Rao , Krajewski Wojciech , Melamud Eugene , Galkin Andrey , Howard Andrew , Kelman Zvi , Reddy Prasad T. , Murzin Alexey G. , Herzberg Osnat
Published: December 2002

The crystal structure of HI0074 from Haemophilus influenzae, a protein of unknown function, has been determined at a resolution of 2.4 Å. The molecules form an up–down, four‐helix bundle, and associate into homodimers. The fold is most closely related to the substrate‐binding domain of KNTase, yet the amino acid sequences of the two proteins exhibit no significant homology. Sequence analyses of completely and incompletely sequenced genomes reveal that the two adjacent genes, HI0074 and HI0073, and their close relatives comprise a new family of nucleotidyltransferases, with 15 members at the time of writing. The analyses also indicate that this is one of eight families of a large nucleotidyltransferase superfamily, whose members were identified based on the proximity of the nucleotide‐ and substrate‐binding domains on the respective genomes. Both HI0073 and HI0074 were annotated “hypothetical” in the original genome sequencing publication. HI0073 was cloned, expressed, and purified, and was shown to form a complex with HI0074 by polyacrylamide gel electrophoresis under nondenaturing conditions, analytic size exclusion chromatography, and dynamic light scattering. Double‐ and single‐stranded DNA binding assays showed no evidence of DNA binding to HI0074 or to HI0073/HI0074 complex despite the suggestive shape of the putative binding cleft formed by the HI0074 dimer. Proteins 2003;50:249–260. © 2002 Wiley‐Liss, Inc.
Insights into the bile acid transportation system: The human ileal lipid‐binding protein‐cholyltaurine complex and its comparison with homologous structures
Authors: Kurz Michael , Brachvogel Volker , Matter Hans , Stengelin Siegfried , Thüring Harald , Kramer Werner
Published: December 2002

Bile acids are generated in vivo from cholesterol in the liver, and they undergo an enterohepatic circulation involving the small intestine, liver, and kidney. To understand the molecular mechanism of this transportation, it is essential to gain insight into the three‐dimensional (3D) structures of proteins involved in the bile acid recycling in free and complexed form and to compare them with homologous members of this protein family. Here we report the solution structure of the human ileal lipid‐binding protein (ILBP) in free form and in complex with cholyltaurine. Both structures are compared with a previously published structure of the porcine ILBP‐cholylglycine complex and with related lipid‐binding proteins. Protein structures were determined in solution by using two‐dimensional (2D)‐ and 3D‐homo and heteronuclear NMR techniques, leading to an almost complete resonance assignment and a significant number of distance constraints for distance geometry and restrained molecular dynamics simulations. The identification of several intermolecular distance constraints unambiguously determines the cholyltaurine‐binding site. The bile acid is deeply buried within ILBP with its flexible side‐chain situated close to the fatty acid portal as entry region into the inner ILBP core. This binding mode differs significantly from the orientation of cholylglycine in porcine ILBP. A detailed analysis using the GRID/CPCA strategy reveals differences in favorable interactions between protein‐binding sites and potential ligands. This characterization will allow for the rational design of potential inhibitors for this relevant system. Proteins 2003;50:312–328. © 2002 Wiley‐Liss, Inc.
A novel approach to the recognition of protein architecture from sequence using fourier analysis and neural networks
Authors: Shepherd Adrian J. , Gorse Denise , Thornton Janet M.
Published: December 2002

A novel method is presented for the prediction of protein architecture from sequence using neural networks. The method involves the preprocessing of protein sequence data by numerically encoding it and then applying a Fourier transform. The encoded and transformed data are then used to train a neural network to recognize a number of different protein architectures. The method proved significantly better than comparable alternative strategies such as percentage dipeptide frequency, but is still limited by the size of the data set and the input demands of a neural network. Its main potential is as a complement to existing fold recognition techniques, with its ability to identify global symmetries within protein structures its greatest strength. Proteins 2003;50:290–302. © 2002 Wiley‐Liss, Inc.
Alternative definitions of comparable case groups and estimates of lead time and benefit time in randomized cancer screening trials
Authors: Kafadar Karen , Prorok Philip C.
Published: December 2002

Randomized screening trials provide the optimal means of assessing the benefit of screening for cancer and other chronic diseases. Unlike therapy trials, however, where strict eligibility criteria assure the comparability of cases of disease in the arms of the trial, the cancer cases identified during follow‐up are a subset of all randomized participants. Furthermore, those cases detected by screening tend to arise from length biased sampling which also can bias estimates of the screening benefit and of average lead time. To reduce or eliminate this bias, we propose several methods for defining comparable groups of cases from the trial arms. We examine, via simulation, these methods with respect to their effects on (i) point and interval estimates of average lead time and average benefit time and (ii) the logrank test statistic for a mortality effect of screening. The most successful new method for defining comparable case groups uses an estimate of the mean sojourn time (mean preclinical duration), and results in nearly unbiased estimates of average lead time and average benefit time as well as an unbiased logrank test statistic. Published in 2003 by John Wiley & Sons, Ltd.
Software release management for component‐based software
Authors: van der Hoek André , Wolf Alexander L.
Published: December 2002

Software release management is the process through which software is made available to and obtained by its users. Until now, this process has been relatively straightforward. However, the emergence of component‐based software is complicating software release management. Increasingly, software is constructed via the assembly of pre‐existing, independently produced, and independently released components. Both developers and users of such software are affected by these complications. Developers need to accurately document the complex and changing dependencies among the components constituting the software. Users must be involved in locating, retrieving, and assembling components in order to appropriately bring the software into their particular environment. In this paper, we introduce the problem of release management for component‐based software and discuss SRM, a prototype software release management tool we have developed that supports both developers and users in the software release management process. Copyright © 2002 John Wiley & Sons, Ltd.