bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new method for the measurement and analysis of noise parameters for MESFETS and HEMTs (invited article)
Authors: Nishida Masao , Uda Hisanori , Harada Yasoo 
Published: July 2007

AbstractWe have developed a new method to measure noise parameters for GaAs MESFETs and HEMTs more accurately, quickly, and reproducibly than the conventional method. We also devised an improved method for automatically calculating a gate‐induced noise current, a drain‐noise current, and their correlation coefficient from the measurement noise and S‐parameters. © 1993 John Wiley & Sons, Inc.
Computer‐aided engineering for microwave and millimeter‐wave circuits using the FD‐TD technique of field simulations (invited article)
Authors: Shibata Tsugumichi , Kimura Hideaki 
Published: July 2007

AbstractThis article describes our techniques for the three‐dimensional full‐wave field simulation of the computer‐aided design of broad‐band circuits operating in the microwave and millimeter wave frequency region. After reviewing the numerical algorithm of the finite‐difference time‐domain approach, the concept of the lumped device model is introduced into the simulation. We then propose an efficient way of calculating the scattering parameters of passive elements that uses the lumped device model as a standard termination of the circuit port. The analysis of a nonlinear circuit directly combined with the field simulation is also presented, and finally, a method of simulating integrated circuits mounted in a package is discussed. © 1993 John Wiley & Sons, Inc.
Computation of hybrid modes in waveguides based on a surface integral formulation
Authors: Swaminathan Madhavan , Sarkar Tapan K. , Petre Peter 
Published: July 2007

AbstractThe interconnections in integrated circuits behave as waveguides at high frequencies. A complete solution to Maxwell's equations is therefore necessary to analyze these lines due to the hybrid nature of the modes propagating in the waveguide. This can be a difficult task for interconnections having complex geometries. A surface integral formulation has been used in this article to compute the dispersion characteristics of hybrid modes propagating in the waveguide. The technique used is an extension of previous work and is based on a method of moments procedure to reduce an integro‐differential equation into a matrix equation using equivalent surface electric and magnetic currents. © 1993 John Wiley & Sons, Inc.
A network model for the aperture coupled microstrip patch
Authors: Dich Mikael , Østergaard Allan , Gothelf Ulrich 
Published: July 2007

AbstractA network model for an aperture coupled microstrip patch is developed. The derivation of the topology of the network model is based on electromagnetic arguments. The values of the components in the network model are found by optimization using input reflection coefficient data computed from a method of moments model. The topology of the network model is described together with a procedure for the determination of the values of its components. After the determination of the values of the components, the network model can be used in a CAD program for a large range of mechanical dimensions, without the need of additional method of moments calculations. © 1993 John Wiley & Sons, Inc.
Time‐domain analysis of electromagnetic coupling of three‐dimensional circuits involving through holes
Authors: Maeda Shuji , Kashiwa Tatsuya , Fukai Ichiro 
Published: July 2007

AbstractPrediction of the mutual effects of the components involving through holes is essential for the design of multilayer circuits to operate at high frequencies. In this article, the characteristics of coupling between adjacent pairs of through holes and between a through hole and microstrip were analyzed using the finite‐difference time‐domain (FD‐TD) method. Numerical results in the time and frequency domains were compared with experimental results; these agreed well. Coupling coefficients were shown to depend on the orientation and distance of the microstrips or a through hole of the secondary from the primary through hole. The distribution of electric field intensity during through hole‐through hole coupling was also shown. The method described appears to hold great promise for substitution for the experimental process. © 1993 John Wiley & Sons, Inc.
Design of different configurations of finite microstrip arrays of circular patches
Authors: Kishk Ahmed A. , Ramaraju Swarajya L. 
Published: July 2007

AbstractA computer code is written to analyze different configurations of finite microstrip arrays. This code will be used as an educational and design tool for students and industrial engineers. The code will be available on PC computers in an interactive graphic mode for the NSF/IEEE Center on Computer Applications in Electromagnetics Education (CAEME). The arrays are made of circular patches with coaxial feeds and exciting different modes. Mutual coupling between the elements and surface wave effects are considered. The conventional dual feed configuration is used to generate circular polarization. Also, circular polarization is realized by sequential feeding of linearly polarized elements. Different array configurations of fixed and scanned beams are analyzed.
Moments‐method analysis of a finite array of arbitrary shaped microstrip patch radiating elements
Authors: Notter Michael John , Parini Clive G. 
Published: July 2007

AbstractA full‐wave model for the analysis of a finite array of arbitrary shaped, probe fed, microstrip elements is presented. The method of moments is used first to obtain a space‐domain solution to the mixed potential integral equation (MPIE) for the isolated element in terms of linear ramp basis functions over triangular subdomains. A second order matrix equation for the array problem is then set up using characteristic current modes as basis functions. These converge rapidly and have orthogonality properties such that only the intermode coupling between separated elements need be computed—a relatively simple operation. Predicted and measured performance characteristics for a 37‐element 8‐GHz array of dual‐mode patches are given which demonstrate the accuracy obtainable with this approach.
The GPI‐anchored CD52 antigen of the sperm surface interacts with semenogelin and participates in clot formation and liquefaction of human semen
Authors: Flori Federica , Ermini Leonardo , La Sala Giovanni Battista , Nicoli Alessia , Capone Antonietta , Focarelli Riccardo , Rosati Floriana , Giovampaola Cinzia Della 
Published: July 2007

AbstractCD52 is a human glycosylphosphatidylinositol (GPI)‐anchored antigen exclusively expressed in leukocytes and epididymal cells. It is also present in sperm, being inserted in their plasma membrane as they pass through the epididymis. In a previous paper we identified a new CD52 form without GPI anchor by fast performance liquid chromatography (FPLC) fractionation of semen components. The form has a lower negative charge than the GPI‐anchored form and occurs as the only CD52 form in prostasome‐free seminal plasma. It was also found associated with the ejaculated sperm, but in contrast to the GPI‐anchored one, it is lost during the capacitation process. In this paper we indicate that (1) the GPI‐anchored CD52 of the sperm surface serves as receptor for semenogelin I during clot formation, (2) liquefaction involves cleavage of the GPI anchor from certain CD52 molecules, releasing sperm from the clot and the soluble antigen bound to semenogelin fragments into the seminal plasma and (3) the clot is a sponge‐like structure housing sperm. Soluble CD52 was immunopurified from the soluble CD52‐containing FPLC fraction using CAMPATH‐1G and was found to be complexed with a semenogelin‐derived peptide of the carboxyl terminal portion of semenogelin I, having the sequence SQTEKLVAGKQI and starting from amino acid 376. Immunoprecipitation and immunoblot analyses using CAMPATH‐1G and anti‐semenogelin as immunoprecipitating antibodies and anti‐gp20 and anti‐semenogelin as immunoblot detectors of the corresponding antigens, confirmed that the soluble CD52 formed a complex with semenogelin. The semenogelin‐CD52 soluble form was found to be a direct consequence of the liquefaction process since only the GPI‐anchored CD52 was recovered in uniquefied semen after recovering sperm and seminal plasma by urea solubilization of the clot. Mol. Reprod. Dev. 75: 326–335, 2008. © 2007 Wiley‐Liss, Inc.
Polyurethane/polyaniline and polyurethane‐poly(methyl methacrylate)/polyaniline conductive core‐shell particles: Preparation, morphology, and conductivity
Authors: Li Chien‐Yu , Chiu Wen‐Yen , Don Trong‐Ming 
Published: July 2007

AbstractPolyurethane/polyaniline (PU/PANI) and polyurethane‐poly(methyl methacrylate)/polyaniline (PU‐PMMA/PANI) conductive core‐shell particles were synthesized by a two‐stage polymerization process. The first stage was to produce a core of PU or PU‐PMMA via miniemulsion polymerization using sodium dodecyl sulfate (SDS) as the surfactant. The second stage was to synthesize the shell of polyaniline over the surface of core particles. Hydrogen chloride (HCl) and dodecyl benzenesulfonic acid (DBSA) were used as the dopant agents. Ammonium persulfate (APS) was used as the oxidant for the polymerization of ANI. Different concentrations of HCl, DBSA, and SDS would cause different conformations of PANI chains and thus different morphologies of PANI particles. UV–visible spectra revealed that the polaron band was blue‐shifted because of the more coiled conformation of PANI chains by increasing the concentration of DBSA. Besides, with a high concentration of DBSA, both spherical‐ and rod‐shape PANI particles were observed by transmission electron microscope, and the coverage of PANI particles onto the core surfaces was improved. The key point of formation of rod‐type PANI particles was that DBSA was served with a high concentration accompanied with the existence of HCl or SDS. The better coverage of PANI particles over the core surfaces by charging higher DBSA concentrations resulted in a higher conductivity of hybrid particles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3902–3911, 2007
Fractal Aspects of Powder Flow and Densification
Authors: Mihranyan Albert , Strømme Maria 
Published: July 2007

AbstractPowder flowability is affected by a number of particulate properties including particle size, surface area, and surface roughness. Surface irregularities play an important role in controlling powder flow properties. In the present work, a relationship was derived between the reactive fractal dimension – representing the fractallity of the part of the surface participating in particle‐particle interactions during powder flow – and the initial increase in density of a powder bed during densification. The reactive and true textural fractal dimensions for a model system comprised of silicified microcrystalline cellulose particles were also experimentally obtained. The concept of the reactive fractal dimension was shown to be helpful for a comprehensive description of the powder densification process. It indicates how rapidly the active interparticulate area involved in particle‐particle interactions grows with powder size reduction. It is suggested that the reactive fractal dimension can be used for describing powder flow behavior and to elucidate the sensitivity of powder flowability to particle size changes.
Hypoxia‐inducible factor‐1α (HIF‐1α) gene polymorphisms, circulating insulin‐like growth factor binding protein (IGFBP)‐3 levels and prostate cancer
Authors: Li Haojie , Bubley Glenn J. , Balk Stephen P. , Gaziano J. Michael , Pollak Michael , Stampfer Meir J. , Ma Jing 
Published: July 2007

AbstractBACKGROUNDThe Hypoxia‐inducible factor‐1 (HIF‐1) plays an important role in regulating angiogenesis in response to hypoxia. Two non‐synonymous polymorphisms (P582S C→T and A588T G→A) in the coding region of the subunit 1α (HIF‐1α) gene have been associated with enhanced stability of the protein and androgen‐independent prostate cancer (CaP). Insulin‐like growth factor binding protein (IGFBP)‐3 mRNA is more abundantly expressed in hypoxia‐related inflammatory angiogenesis and recent in vivo data suggest that IGFBP‐3 has direct, IGF‐independent inhibitory effects on angiogenesis.METHODSWe examined the association of these polymorphisms with CaP among 1,072 incident cases and 1,271 controls, and further explored their joint associations with various prediagnostic plasma vascular endothelial growth factor (VEGF), IGF‐I, and IGFBP‐3 levels.RESULTSNeither the P582S nor the A588T polymorphism was associated with risk of overall or metastatic/fatal CaP. However, we found that, among men with the homozygous CC wild‐type (but not CT/TT) of the HIF‐1α P582S, higher IGFBP‐3 levels (≥ vs. <median) were associated with a 28% (95% CI, 0.55–0.95; Pinteraction = 0.01) lower risk of overall CaP and a 53% (0.25–0.88; Pinteraction = 0.11) lower risk of metastatic and fatal CaP. The A588T polymorphism was too rare to assess interactions.CONCLUSIONSThe two HIF‐1α gene polymorphisms were not directly associated with CaP, but the interaction between the P582S polymorphism and IGFBP‐3 merits further evaluation in mechanistic studies. Prostate 67: 1354–1361, 2007. © 2007 Wiley‐Liss, Inc.
Shared‐care arrangements and the primary/secondary‐care interface
Authors: Khambh Jas , Barnick Christian 
Published: July 2007

AbstractSpecialist and high‐risk drugs are increasingly being prescribed in the community due to a shift in services from secondary to primary care. This article describes the shared‐care arrange ments that need to be in place to ensure safe and effective treatment. Copyright © 2007 Wiley Interface Ltd
Rayleigh‐debye scattering of light of anthracene crystals
Authors: Uzarczyk A. , Myja M. , Godlewski J. 
Published: July 2007

AbstractLight scattering in pure solids is due to the extended discrete variation of the dielectric constant. To describe the scattering of light in anthracene crystals the Rayleigh‐Debye theory is used. A direct relation between the nature of structural defects in molecular solids and the spatial variation of the dielectric constant is found. On the basis of the relation, the form of the scattering correlation function is derived. Theoretical relations describing the intensity of light scattering in molecular crystals are applied to experimental data concerning the intensity of scattered light in anthracene crystals as a function of wavelength for small angles of scattering. It is found that the diameter of the scattering centres in anthracene is of the order of few μm with concentration about 108 cm−3.
Equation of State and Thermal Expansivity under the Effect of High Pressure and High Temperature
Authors: Kumar M. , Upadhyay S. P. 
Published: July 2007

AbstractA simple method is developed to investigate interatomic separations and thermal expansion coefficients at pressures ranging from the atomspheric one up to the structural transition pressure, and temperatures ranging from RT to the melting temperature. The calculations are performed using an ionic model based on Harrison's quantum mechanical form for the overlap repulsive energy which takes into account the interactions up to second neighbours. The van der Waals dipole‐dipole and dipole‐quadrupole interactions evaluated from more accurate methods are also included in the model. The results depend sensitively on temperature and pressure. The thermal expansion coefficient increases with temperature, while this increase becomes rather slow as pressure is increased. A strong decline of the thermal expansion coefficient with pressure at a constant temperature is also obtained. The results are compared with available experimental data, and good agreement supports the validity of the method developed in the present work.
Structural Phase Stability in BaSe
Authors: Kalpana G. , Palanivel B. , Rajagopalan M. 
Published: July 2007

AbstractThe band structure of BaSe in both Nad‐type (Bl) and CsCl‐type (B2) structures is determined using the self‐consistent linear muffin‐tin orbital method within the atomic sphere approximation (LMTO‐ASA). In agreement with the earlier observations, the band gap is found to be indirect in both Bl and B2 structures. The calculated values of the band gaps are compared with the experimental values. From the ASA total energy calculations, the structural phase stability of BaSe is studied. At ambient conditions BaSe is found to be stable in the Bl structure. It undergoes a structural transition to the B2 structure at about 55 × 108 Pa, associated with a volume reduction of 14.3%. The equilibrium lattice constants for both Bl and B2 structures and the transition pressure are compared with earlier experimental results.
Recombination of Alloy‐Trapped Excitons in Ternary Solid Solutions with Common Cation Components
Authors: Reznitsky A. , Baranovskii S. D. , Tsekoun A. , Klingshirn C. 
Published: July 2007

AbstractA new analysis of absorption and photoluminescence (PL) spectra of CdS1−xSex and ZnSe1−xTex solid solutions at liquid helium temperature is presented. It is shown that the high‐energy side of the luminescence band of excitons trapped in the band tail can be fitted by a simple exponential function exp (ϵ/ϵPL), the parameter EPL being proportional to the Urbach parameter ϵ0 in the absorption spectra. This analysis provides the most direct evaluation of the concentration N0 of localized tail states. The values N0a3 = (4.5 ± 0.7) × 10−3 and (2.5± 0.5) × 10−3 are obtained for CdS1−xSex and ZnSe1−xTex respectively, which lead to the estimations N0≈1.5 × l019and ≈ 8 × 1018 cm−3 in these solid solutions, using the previously determined value a ≈ 0.7 nm. A new model for the energy relaxation of excitons through the localized tail states is suggested which takes into account exciton‐phonon interactions and non‐radiative recombination of excitons.
Galvanomagnetic Transport of the Two‐Dimensional Electron Gas in In0. 53Ga0. 47As Quantum Wells
Authors: Ghosh P. K. , Chattopadhyay D. 
Published: July 2007

AbstractGalvanomagnetic coefficients of the two‐dimensional (2D) electron gas in In0.53Ga0. 47As quantum wells are studied for classical magnetic fields by an iterative solution of the Boltzmann equation considering the degeneracy of the distribution function. Scatterings from polar optic phonons, deformation potential acoustic and piezoelectric phonons, inonized impurities, and alloy disorder are considered. The magnetoresistance coefficient is found to be more sensitive than the Hall mobility and the Hall ratio to changes in temperature, 2D carrier concentration, channel width, ionized impurity concentration, and magnetic field.
X‐Ray Absorption Fine Structure Investigation of the High Pressure Phase of KBr and RbCl. Full Multiple Scattering Analysis
Authors: Soldatov A. V. , Ivanchenko T. S. , Stekhin I. E. , Bianconi A. , Ingalls R. 
Published: July 2007

AbstractX‐ray absorption near edge structure (XANES) of the Br and Rb K edge of the high pressure (B2) phase of KBr and RbCl is analyzed. A full multiple scattering method is used to investigate the conduction band structure of KBr and RbCl. Theoretical K‐edge absorption spectra obtained over a large energy interval are used to analyze the experimental data. As in the case of the low pressure (B1) phase, XANES is found to be determined by multiple scattering of photoelectrons in a large‐size cluster (30 atoms or more). For the energy interval up to 50 eV above the main edge, the single scattering approximation seems to be less satisfactory. A comparative analysis of XANES of the two compounds in two different crystal phases makes it possible to conclude on the role of the local symmetry around the absorbing site and the characteristics of the surrounding atoms in the formation of XANES and conduction band of the compounds investigated.
Electronic Structure of Copper‐Oxide Based High‐Tc Superconductors and Related Compounds from KK Analysis of Reflectance
Authors: Ghosh B. , Neogy C. , Deb S. K. , Nag A. 
Published: July 2007

AbstractIt is demonstrated that Kramers‐Kronig (KK) analysis of reflectance data using various physically acceptable extrapolation formulae yields results which agree quantitatively when the parameters are obtained by suitable statistical methods. The absorption and Im (−1/ϵ) spectra obtained by the KK analysis of reflectance data (0.5 to 6.1 eV) of REBa2Cu3O7−x (RE = Y, Dy, Ce) and different combinations of CuO, BaO, and RE oxides strongly suggest that in these 123 layered cuprates superconductivity results when excitons (near 1.4eV) in the polarizable layers and carriers (hole or hole‐polarons) in the conducting layers are both present in sufficient number.
From Liquid to Solid: Residual Disorder in the Local Environment of Oxygen‐Coordinated Zirconium
Authors: Landron C. , Douy A. , Bazin D. 
Published: July 2007

AbstractX‐ray absorption is used as a chemically specific structural probe to investigate the short‐range order around zirconium cations in various crystallized, amorphous, or vitreous systems containing oxygencoordinated zirconium in order to connect it to the disorder in the environment of this cation in the liquid solution from which they are produced. The comparison of the various analyses gives detailed information on the local structure around the zirconium atoms. The type and the level of randomness is discussed. The radial distribution functions of the various samples with disordered structure are compared with the corresponding crystalline functions. The effects of disorder on the first two coordination shells are derived for these samples.
Elastostatic Green's Function and Its Spatial Derivatives for Cubic Symmetry. Exactly Solvable Cases
Authors: Morawiec A. 
Published: July 2007

AbstractThe Green's function and its spatial derivatives for a cubic infinite medium in cases when they can be obtained in form of explicit analytic expressions are presented. It is known that the problem reduces to a sextic equation which, in general case, is unsolvable. Symbolic solutions, however, can be given in some special cases. New formulae for directions lying in (001) and (110) planes are given. Full solutions for [100] and [111] directions are presented as examples. First derivatives of the Green's function with respect to spatial coordinates are also expressed through the roots of the sextic equation and the solutions for the same special directions are given.
Electron Energy Spectrum and Wave Functions in Quantum Wells on the Base ofIV‐VI Narrow‐Gap Semiconductors
Authors: Dugaev V. K. , Petrov P. P. 
Published: July 2007

AbstractThe results of analytical calculations of the energy spectrum and wave functions of electrons localized within quantum wells grown on IV‐VI narrow‐gap semiconductors are presented. The eigenvalue equations determining the size‐quantized levels are in agreement with previous reports in literature, but some aspects concerning the symmetry of wave functions are elucidated. The wave functions for localized states are presented in explicit form. Using these wave functions as a new basis we obtain the effective Hamiltonian for electrons in quantum wells. The energy spectrum of electrons in the presence of a magnetic field is presented as well.
The Uniaxial Strain Effect on the Ternary Alloy Semiconductor Ga1−xAlxP
Authors: Badi N. , Abid H. , Soudini B. , Amrane N. , Driz M. , Dufour J. P. , Aourag H. , Khelifa B. 
Published: July 2007

AbstractThe effect of static uniaxial compression along the cubic direction 〈100〉 is studied. The empirical pseudo‐potential method (EPM) within the so‐called virtual crystal approximation (VCA) is used to compute the electronic charge densities at selected k‐points of the valence and the conduction band edges in Ga1−xAlxP. These charge densities are used to study the modification of the bonding and the electronic properties of the alloy with respect to the composition and the lattice constant variations along the 〈100〉 direction.