bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential output of the high‐sensitivity rod photoreceptor: AII amacrine pathway
Authors: Petrides Artemis , Trexler E. Brady 
Published: February 2008

AbstractIn the mammalian retina, the scotopic threshold of ganglion cells is in part dependent on how rod inputs are summed by their presynaptic cone bipolar cells. For ON cone bipolar cells, there are two anatomical routes for rod signals: 1) cone photoreceptors receive inputs via gap junctions with the surrounding, more numerous rods; and 2) ON cone bipolar cells receive highly convergent input via gap junctions with AII amacrine cells, which each receive input from hundreds of rods. Rod‐cone coupling is thought to be utilized at higher photon fluxes relative to the AII‐ON cone bipolar pathway due to the impedance mismatch of a single small rod driving a larger cone. Furthermore, it is widely held that the convergence of high‐gain chemical synapses onto AIIs confers the highest sensitivity to ON cone bipolar cells and ganglion cells. A lack of coupling between one or more types of ON cone bipolar cells and AIIs would obviate this high‐sensitivity pathway and explain the existence of ganglion cells with elevated scotopic thresholds. To investigate this possibility, we examined Neurobiotin and glycine diffusion from AIIs to bipolar cells and found that approximately one‐fifth of ON cone bipolar cells are not coupled to AIIs. Unlike AII‐AII coupling, which changes with ambient background intensity, the fraction of noncoupled ON cone bipolar cells was unaltered by dark or light adaptation. These data suggest that one of five morphologically distinct ON cone bipolar cell types is not coupled to AIIs and suggest that AII‐ON cone bipolar coupling is modulated differently from AII‐AII coupling. J. Comp. Neurol. 507:1653–1662, 2008. © 2008 Wiley‐Liss, Inc.
A model of incompressible isotropic hyperelastic material behavior using spline interpolations of tension–compression test data
Authors: Sussman Theodore , Bathe Klaus‐Jürgen 
Published: February 2008

AbstractWe present a model of incompressible isotropic hyperelastic material behavior based on a strain energy description separable in terms of logarithmic strains and piecewise spline interpolations of uniaxial tension–compression test data. Valuable attributes are that no fitting of model constants is carried out and the model replicates even physically complicated test data very accurately for small and large strains and for tension and compression. The model is well suited for use in finite element analysis. Copyright © 2008 John Wiley & Sons, Ltd.
An improved Cosserat point element for axisymmetric problems in nonlinear elasticity: Comparison with other element formulations
Authors: Jabareen M. , Rubin M. B. 
Published: February 2008

AbstractAn improved quadrilateral Cosserat point element (CPE) has been developed for modeling torsionless axisymmetric problems in nonlinear elasticity. The CPE approach differs from standard finite element methods in that the element is considered to be a structure that is modeled using a strain energy function for homogeneous and inhomogeneous responses. The strain energy function for inhomogeneous deformations is generalized to include dependence on the reference geometry of irregular‐shaped elements. The quadrilateral CPE has four nodes with eight degrees of freedom, it needs no integration over the element region or user specified hourglass parameters. A number of examples have been considered which compare the response of the improved CPE with those of all of the four noded hyperelastic elements implemented in the computer codes ABAQUS, ADINA, ANSYS and FEAP. These examples demonstrate that the improved CPE is applicable for thin plates and shells, is as accurate as elements based on enhanced strain and incompatible mode methods and is as robust as the full integration element. Consequently, the CPE is truly a user‐friendly element that can be used with confidence for challenging problems in axisymmetric nonlinear elasticity. Copyright © 2008 John Wiley & Sons, Ltd.
Application of molecular dynamics computer simulations in the design of a minimal self‐replicating molecular machine
Authors: Weroński Paweł , Jiang Yi , Rasmussen Steen 
Published: February 2008

AbstractIt is commonly agreed that a chemical assembly of molecules can be considered alive if it can ingest resources and convert them into building blocks; has the ability to grow and self‐reproduce; and can evolve. In the design proposed by Rasmussen and Chen (Science 2004, 303, 963) the assembly or protocell could be as simple as a small micellar surfactant aggregate acting as a container, anchoring an informational molecule to its exterior and incorporating a metabolism within the oily interior. We present several examples of modeling such a system with molecular dynamics computer simulations. © 2008 Wiley Periodicals, Inc. Complexity, 2008.
Resonant oscillations of a granular cluster
Authors: Khain Evgeniy 
Published: February 2008

AbstractDriven granular media is a fascinating example of intrinsically non‐equilibrium system. I consider an ensemble of inelastically colliding hard disks in a channel driven by two opposite thermal walls with different temperatures. When the inelasticity of collisions is large enough, a dense cluster, located closer to the colder wall, is formed. The steady state profiles are computed from the equations of granular hydrodynamics, and a good agreement with the results of molecular dynamics simulations is found. When the temperature of one of the thermal walls is varied periodically, a dense cluster develops oscillations. The oscillations amplitude reaches its maximum in a resonance, when the frequency of driving is roughly equal to the hydrodynamic frequency of oscillatory acoustic modes in the system. © 2008 Wiley Periodicals, Inc. Complexity, 2008.
Investigation of optical band gap in potassium acid phthalate single crystal
Authors: Krishnan S. , Raj C. Justin , Dinakaran S. , Das S. Jerome 
Published: February 2008

AbstractOptical absorption in photonic crystals of potassium acid phthalate has been measured at room temperature, from which the band gap has been determined and the optical band gap was calculated by using absorption spectrum. The analysis of absorption coefficient in the absorption region reveals a direct band gap of 3.70 eV. Further this study includes the theoretical calculations to determine the optical constant of the material and a technique for photonic band gap tuning which is minimally required to develop the optoelectronic device. It was confirmed that potassium acid phthalate crystal has maximum transparency in the entire visible region and hence it exhibits industrial application oriented properties. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of the growth processes from vapor phase of silicon carbide epitaxial layers: Thermodynamic analysis of the high temperature processes in the system Si‐C‐H‐Cl
Authors: Lilov S. K. 
Published: February 2008

AbstractIn the present work are presented the results of the thermodynamic analysis of the interaction processes in the system Si‐C‐H‐Cl in the temperature interval 1000‐3000 K. The equilibrium pressures of the components in the system Si‐C‐H‐Cl with taking account the formation of the condensed phases C, Si and SiC have been determined. The optimal conditions giving the maximum yield of silicon carbide by pyrolysis of mixture of volatile compounds of carbon and silicon have been defined. The thermodynamic analysis of the examined system showed that the increasing of the content of hydrogen in the initial mixture allows to decrease the optimal temperature for obtaining of silicon carbide by the method of pyrolysis and essentially to increase its maximum possible yield. (© 2008 WILEY ‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of additives in supersaturated binary and ternary solutions on cluster growth by gravity driven concentration gradient studies
Authors: Anandha Babu G. , Ramasamy P. 
Published: February 2008

AbstractThe concentration gradients formed in long column supersaturated solutions of the binary systems Potassium dihydrogen phosphate ‐ Water, Benzophenone ‐ Ethanol, Ammonium dihydrogen phosphate – Water, Potassium hydrogen phthalate – Water and ternary systems Potassium dihydrogen phosphate – Potassium chloride ‐ Water, Benzophenone – Urea ‐ Ethanol, Ammonium dihydrogen phosphate – Urea ‐ Water, Potassium hydrogen phthalate – Ethylenediaminetetraacetic acid – Water under stirred and non‐stirred conditions have been studied. The solution concentration was measured at different heights, at different degrees of supersaturation and at different times. Weight average molecular weight, Degree of Association, Number average molecular weight, Average number of molecules per cluster and weight average cluster diameter were calculated for binary and ternary supersaturated solutions under stirred and non‐stirred conditions. Under stirred conditions concentration gradient of all the above mentioned systems decrease compared to non‐stirred conditions. The cluster sizes are estimated from concentration gradient data in the presence and absence of additives and also corresponding changes in metastable zonewidths are studied. The changes in concentration gradients of supersaturated solutions appear to be a reliable indicator of the effect of additives on cluster growth and nucleation. As long column of solution is used in growing crystal by Sankaranarayanan‐Ramasamy method the effect of gravity driven concentration gradient on critical column length is investigated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Wet‐chemical synthesis and characterization of NiBi nano‐ and micro‐particles
Authors: Odeh I. M. , Mahmoud S. , Vassilev G. P. 
Published: February 2008

AbstractPreparation and characterization of NiBi nano‐ and micro‐particles are presented. Firstly, predetermined compositions were obtained by simultaneous precipitation from solutions of Bi(NO3)3 and Ni(NO3)2. The precipitates were heated under oxygen flow and in air, and thereafter reduced to metals under hydrogen flow at 673 K. Correlation between the predetermined and the actual compositions of the products was found. Characterization of the precipitates was carried out employing X‐ray diffraction, scanning and transmission electron microscopy. Nickel‐bismuth intermetallic phase (NiBi) particles with nano‐ and micro‐dimensions were observed in the samples after reduction. The other possible Ni–Bi intermediate phase (NiBi3) did not form at these conditions although its presence was expected according to the phase diagram. This finding might be useful for the implementation of Bi‐based solders where the growth of the compound NiBi3 in the solder joints must be prevented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of domain structures in PZNT93/7 crystals by chemical etching
Authors: Jin Min , Xu Jiayue , Wu Aiying , Li Xinhua , Shen Hui , He Qingbo 
Published: February 2008

AbstractThe domain structures in 0.93Pb (Zn1/3Nb2/3)O3‐0.07PbTiO3 (PZNT93/7) crystals were investigated by chemical etching technique. Original antiparallel 180° domains of size 20–40 μm were observed on the surface of as‐grown PZNT93/7 crystal. It was found the domain states are sensitive to the stress field induced by mechanical processing or impurities. As the composition of PZNT93/7 crystal was located near the morphotropic phase boundary, various domain configurations were observed. On the <001>‐oriented wafer, the etched a ‐ and c ‐domains revealed homogenous and island‐like patterns. The c ‐domains consist of upper and lower height regions corresponding to the tail and head of the polarization, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the capability of revealing the pseudosymmetry of the chalcopyrite‐type crystal structure
Authors: Abou‐Ras D. , Gibmeier J. , Nolze G. , Gholinia A. , Konijnenberg P. 
Published: February 2008

AbstractThe tetragonal crystal‐structure type of chalcopyrites (chemical formula AIBIIICVI2) is a superstructure of sphalerite type. The c /a ratio differs generally from the ideal value 2, i.e., the crystal structure is pseudocubically distorted. For CuInSe2 and CuGaSe2 thin films, simulations demonstrate that it is theoretically possible to reveal the tetragonality in electron backscatter‐diffraction (EBSD) patterns for CuGaSe2, whereas it may not be possible for CuInSe2. EBSD experiments on CuGaSe2 thin films using the ”Advanced Fit” band‐detection method show that it is possible to extract accurate misorientation‐angle distributions from the CuGaSe2 thin film. Pole figures revealing the texture of the CuGaSe2 thin film are shown, which agree well with X‐ray texture measurements from the same layer. (© 2008 WILEY ‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reduction of domain wall width in VTE treated near stoichiometric LiNbO3 crystals
Authors: Kar S. , Bartwal K. S. 
Published: February 2008

AbstractLiNbO3 is a ferroelectric crystal and grows with multi domains. Different domains are separated by boundaries which are known as domain boundaries. Domain walls for congruent and VTE (Vapor Transport Equilibration) treated near stoichiometric lithium niobate samples were visualised in different crystallographic directions using chemical etching technique. The sample is etched in the mixture of HF and HNO3 (in 1:2 volume ratios) for 10 minutes at boiling temperature. Measured domain wall width was found approximately 15‐20 µm for congruent (CLN) and it reduces to 1‐3 µm for VTE treated near stoichiometric (SLN). Activation energies were also measured by two‐probe method and found to be increasing in stoichiometric sample. This activation energy is related to defect density in the crystals. Activation energy is higher for less defective crystals. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application of mean‐separation‐works method to protein crystal nucleation
Authors: Nanev Christo N. 
Published: February 2008

AbstractUsing mean‐separation‐works method of Stranski and Kaischew calculations of nucleus form and energy barrier for its formation are performed for globular protein crystals. This is done on the basis of a simple model suggested for crystal nucleation of such proteins. The prerequisite for the model is the fact that strict selection of definite sticky patches on protein molecule surface is obligatory for forming crystal lattices. The calculation results are in agreement with experimental data. (© 2008 WILEY ‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystallization of AgGaS2 melts enriched with Ag2S and Ga2S3
Authors: Kokh K. A. , Sinyakova E. F. , Politov A. A. 
Published: February 2008

AbstractIn this work we consider experiments with directed crystallization of melts with slight deviation from stoichiometric composition of AgGaS2. The evolution of melt composition was calculated for both experiments using measured chemical composition of the solid phase. Also the difference in unit cell parameters and luminescence spectra for AgGaS2 grown from the melts was found. Both monocrystal samples and samples synthesized from elementary Ag, Ga and S were used for thermal analyses. Obtained data suggests that different ways of preparing the samples are responsible for defects concentration and thus for so wide range (70°C) of melting temperatures reported in scientific literature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and microhardness studies of pure and thiourea doped glycine phosphite single crystal
Authors: Ezhil Vizhi R. , Kalainathan S. , Baghavan Narayana G. 
Published: February 2008

AbstractFerroelectric Glycine Phosphite (GPI) crystal have been grown from aqueous solution employing the slow cooling technique. As the crystal solubility in water depends on temperature, single crystals were grown. Transparent, colourless crystals with habit morphology weighing about 8g were obtained with in a month. The same procedure was used to grow single crystals of 10 wt% of Thiourea doped GPI (TUGPI). Formation of a new crystal was confirmed by Powder X‐ray diffraction studies as well as FTIR studies. Crystalline quality were found using rocking curve for both the crystals. Due to the presence of Thiourea in TUGPI, it improves the crystalline perfection and also enhances the growth rate. The variation of hardness on (010) faces of monoclinic GPI and TUGPI crystals, with load were studied.Vickers hardness numbers, Hv were found to decrease with the increase in load. The value of Mayer's index, ‘n ’ was found to be greater than 1.6 for GPI and TUGPI showing soft‐material category. The results are discussed in detail. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental investigation of different configurations for the seeded growth of SiC crystals via a VLS mechanism
Authors: Boutarek N. , Bonda M. , Chaussende D. , Madar R. 
Published: February 2008

AbstractThe growth of SiC crystals or epilayers from the liquid phase has already been reported for many years. Even if the resulting material can be of very high structural quality and the possibility to close micropipes was demonstrated, handling the liquid phase still is a challenge. Moreover, it is highly difficult to stabilize the C dissolution front and then to stabilize the growth front over a long growth time. Based on the Vapour‐Liquid‐Solid (VLS) mechanism, we present a new configuration for the growth of SiC single crystal which should allow first to simplify the liquid handling at high temperature and second to precisely control the crystal growth front. The process consists in a modified top and bottom seeded solution growth method, in which the liquid is held under electromagnetic levitation and fed from the gas phase. 3C‐SiC crystals exhibiting well‐faceted morphology were successfully obtained at 1100‐1200 °C with exceptional growth rates, varying from 1 to 1.5 mm/h in Ti‐Si melt. It was shown that the nucleation density decreases simultaneously with increasing propane partial pressure. At 1200‐1400 °C, thick homoepitaxial 6H‐SiC layers were successfully obtained in Co‐Si and Ti‐Si melts, with growth rate up to 200 µm/h. Large terraces with smooth surfaces are observed suggesting a layer by layer growth mode, and the influence of the system pressure was demonstrated. It was shown that the terrace size decrease simultaneously with increasing propane partial pressure which suggests the beginning of a two dimensional to three dimensional growth mode transition. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defect structure and optical fixing holographic storage of Mg:Mn:Fe:LiNbO3 crystals
Authors: Wei Zheng , Qiang Gui , Yuheng Xu 
Published: February 2008

AbstractMg:Mn:Fe:LiNbO3 crystals were grown by the Czochralski method. The defect structure was analyzed by UV‐vis spectra and IR spectra. The holographic storage of Mg:Mn:Fe:LiNbO3 crystals was measured by the two color fixed method. The results show that with the increase of MgO doping concentration, the writing time becomes shorter, the dynamic range decreases, photorefractive sensitivity increases and fixing diffraction efficiency decreases. When the MgO doping concentration exceeds 4.5 mol%, the fixing diffraction efficiency approaches zero. The effect of doping Mg ions on the holographic storage properties of Mn:Fe:LiNbO3 crystals is discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In situ measurement of growth kinetics of {100} KDP crystal faces in the presence of polyphosphate impurities
Authors: Liu Bing , Fang Chang‐Shui , Wang Sheng‐Lai , Mou Xiao‐Ming 
Published: February 2008

AbstractThe face growth rate and critical supersaturation of {100} face were in situ measured using the laser‐polarization‐interference technique in the presence of potassium pyrophosphate, trimetric sodium phosphate and sodium hexametaphosphate impurities. The polyphosphate impurities inhibit the growth rate of prismatic faces. The face growth rate as a function of supersaturation at different impurity concentrations, as well as critical supersaturation as a function of impurity concentrations, was found in good agreement with a two‐dimensional nucleation model in the pure system and Kubota and Mullin's model in the presence of impurities. The average distance L between active sites available for impurity adsorption as well as the edge free energy was calculated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A fast‐convergent fairness scheme for resource allocation in RPR networks
Authors: Liu Chuan‐Gang , Li Jung‐Shian 
Published: February 2008

AbstractIn this paper, we propose a fast‐convergent fairness scheme in IEEE 802.17 resilient packet ring (RPR) networks. In the proposed scheme, each station could rapidly approach fair rate by estimating the number of unbounded flows at each link. In addition, the fast‐convergent scheme could prevent rate oscillations in theRPR aggressive modescheme under unbalanced traffic. The estimation mechanism is simple and scalable since it is stateless without per‐flow management. Through analytical and simulation evaluations our scheme was found to be stable and speedy when compared with 802.17RPRfairness scheme or the proposeddistributed virtual‐time scheduling in ringsscheme. Our scheme could allocate bandwidth fairly and smoothly among flows and achieve high utilization at the same time in theRPRnetwork. Copyright © 2008 John Wiley & Sons, Ltd.
40 Jahre Deutsches Institut für Bautechnik – 40 Jahre sicheres und innovatives Bauen. Die Gründung des DIBt
Authors: Schmidt‐Staudinger Renate 
Published: February 2008

AbstractDas Deutsche Institut für Bautechnik (DIBt) feiert 2008 sein 40‐jähriges Bestehen. 40 Jahre DIBt stehen für 40 Jahre Sicherheit und Innovationen im Bauwesen und für 40 Jahre Zulassungswesen einer zentralen Institution in der Bundesrepublik Deutschland. Ein geeigneter Anlass also, um die Geschichte des Instituts in den DIBt Mitteilungen in einer kleinen Serie näher zu beleuchten. Den Auftakt unserer Betrachtung bilden die Anfänge des deutschen Zulassungswesens und der Gründungsprozess des DIBt von 1951 bis 1968.
Synthesis, Structure, and Magnetic Properties of a New Three‐Dimensional Iron Phosphite, [C4N2H12][Fe4(H2O)3(HPO3)7]·(H2O)xx= 0.6
Authors: Mandal Sukhendu , Banerjee Debamalya , Bhat S. V. , Pati Swapan K. , Natarajan Srinivasan 
Published: February 2008

AbstractA new open‐framework iron phosphite, [C4N2H12][Fe4(H2O)3(HPO3)7]·(H2O)xx= 0.6 (1), has been prepared by the hydrothermal reaction between FeCl3·6H2O, H3PO3, and piperazine. The three‐dimensional structure is comprised of a network of FeO6, FeO5(H2O), and HPO3polyhedral units connected through their vertices. The structure has layers formed by the well‐known 4.6.12‐net connectivity and is stacked in an AAAA... sequence, penetrated by the one‐dimensional pillar units, forming a three‐dimensional pillared‐layer structure. This connectivity gives rise to two independent 12‐ring channel systems. Magnetic studies indicate antiferromagnetic behavior at high temperatures, with a small ferromagnetic polarization at low temperatures.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)