bluuebunny/crossref_metadata_2025_split huggingface dataset:
A microstrip patch antenna with broadened beamwidth
Authors: Ning Chen Zhi , Kian Toh Wee , Qing Xianming 
Published: April 2008

AbstractA beamwidth broadening technique for a microstrip patch antenna is presented here. The antenna consists of a patch radiator with two phase‐reversed auxiliary radiators. This technique allows the beamwidth of a microstrip antenna with a large aspect ratio to be broadened at the expense of a slight increase in its lateral size. By using the auxiliary radiators, up to 16% increase in the H‐plane beamwidth is achieved. This antenna is also analyzed using a modified aperture model. Other existing beamwidth broadening techniques are compared and their applications listed. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1885–1888, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23539
An alternative implementation of time domain adaptive integral method for surface integral equations
Authors: Xin‐Yi Ma , Dang‐Wei Wang , Yi Su , Jie Sheng 
Published: April 2008

AbstractThis letter presents an alternative implementation of the time domain adaptive integral method (TD‐AIM) for solving combined field integral equation (CFIE) pertinent to electromagnetic surface scattering phenomena. We use the cubic spline as temporal basis function and analytically remove the rot operator from the integrals of far‐zone interactions. Furthermore, we decompose the huge 4D FFT into several smaller ones in time domain. Consequently, the TD‐CFIE can be solved with relatively littler memory and computational resources accurately. Simulation results have been presented and demonstrated the effectiveness of the proposed implementation method. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1819–1822, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23542
Analysis of compact H‐shaped microstrip antenna
Authors: Ansari J. A. , Kesh Dubey Satya , Singh Prabhakar , Khan R. U. , Vishvakarma Babau R. 
Published: April 2008

AbstractAnalysis of H‐shaped patch is carried out using equivalent circuit model. It is found that the antenna exhibits dual resonance behavior which is very sensitive to the dimensions of the notch. The theoretical results of proposed method are compared with experimental and theoretical result reported earlier using FDTD method. Comparison with other reported results justify the veracity of the proposed method. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1779–1784, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23543
Compact ultrawideband square slot antenna with an asymmetric protruding stub
Authors: Shiu Jen‐Yi , Sze Jia‐Yi , Tu Po‐Jen 
Published: April 2008

AbstractA new compact ultra‐wideband (UWB) square slot antenna fed by a coplanar waveguide (CPW) is proposed. A large impedance bandwidth of more than 13 GHz (2.8–16 GHz) was obtained by asymmetrically widening the tuning stub that is extended from the signal strip of the CPW into the square slot. The larger and smaller widened parts of the asymmetric tuning stub can be easily adjusted to achieve good impedance matching in the lower and upper regions, respectively, of the entire VSWR ≤ 2 band. The simple design procedure along with reasonably agreed measured and simulated results is presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1776–1779, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23544
A fully single‐ended GaInP/GaAs HBT micromixer using an integrated active LO balun
Authors: Wu Tzung‐Han , Lin Yi‐Chen , Meng Chinchun , Wu Tse‐Hung , Wei Hung‐Ju , Huang Guo‐Wei 
Published: April 2008

AbstractA Gilbert micromixer is demonstrated in this paper using GaInP/GaAs HBT technology. By using an on‐chip active LO balun, the micromixer with the single‐ended RF, LO, and IF ports is suitable for hybrid RF system applications. The port‐to‐port isolation has its best performance when the LO signal is balanced. The fully matched high‐linearity micromixer has the conversion gain of 12 dB, IP1dB of −9 dBm, IIP3 of 1 dBm when fIF(input) = 300 MHz, fLO = 3.5 GHz, and fRF(output) = 3.8 GHz. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1918–1921, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23549
Scheduling parallel dedicated machines with the speeding‐up resource
Authors: Kellerer Hans , Strusevich Vitaly A. 
Published: April 2008

AbstractWe consider a problem of scheduling jobs on m parallel machines. The machines are dedicated, i.e., for each job the processing machine is known in advance. We mainly concentrate on the model in which at any time there is one unit of an additional resource. Any job may be assigned the resource and this reduces its processing time. A job that is given the resource uses it at each time of its processing. No two jobs are allowed to use the resource simultaneously. The objective is to minimize the makespan. We prove that the two‐machine problem is NP‐hard in the ordinary sense, describe a pseudopolynomial dynamic programming algorithm and convert it into an FPTAS. For the problem with an arbitrary number of machines we present an algorithm with a worst‐case ratio close to 3/2, and close to 3, if a job can be given several units of the resource. For the problem with a fixed number of machines we give a PTAS. Virtually all algorithms rely on a certain variant of the linear knapsack problem (maximization, minimization, multiple‐choice, bicriteria). © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008
PANI–LDPE composites: Effect of blending conditions
Authors: Cote M. , Cortés M.T. , Beltrán D. , Ortiz P. 
Published: April 2008

AbstractA composite based on polyaniline (PANI) and low density polyethylene (LDPE) with electrical conductivity was developed. Polyaniline was polymerized by chemical oxidation and doped with dodecyl‐benzene‐sulfonic acid (DBSA). PANI–LDPE composites were prepared via melt blending and the films were obtained by compression molding. The influence of three variables of the blending (temperature, [PANI], rotor speed) on conductivity, microstructure and mechanical properties of the composites was studied by means of statistical tools and a 23 experimental design. The results show that the PANI concentration is the most influential variable, which mainly affects the conductivity and the elongation at break of the composites. These changes are related to the microstructure of the composites. Statistically, the other variables don't show significant influence on conductivity and mechanical properties in the studied range. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers.
Copolymerization of aniline and styrene using various surfactants in aqueous media
Authors: Eisazadeh Hossein , Kavian Amin 
Published: April 2008

AbstractPolyaniline/polystyrene (PAn/PS) copolymer was prepared in the aqueous solution by copolymerization of styrene and aniline using potassium iodate (KIO3) and ammonium persulfate ((NH4)2S2O8) as an oxidant in the presence of various surfactants such as poly(ethylene glycol), hydroxypropylcellulose, and surfactive dopant sodium dodecylbenzenesulfonate. The PAn/PS copolymer was characterized in terms of conductivity, morphology, chemical structure, and glass transition temperature. The results indicate that the morphology, conductivity, and glass transition temperature of products are dependent on the type of surfactant. Furthermore, it was found that addition of styrene monomer into stirred aqueous solution influences the surface morphology. The chemical structure and glass transition temperature of product were studied by Fourier transform infrared spectroscopy and differential scanning calorimetry respectively. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Effect of surface treatment on the tribological performance of carbon fiber reinforced thermoplastic polyimide composites
Authors: Li J. , Cheng X.H. 
Published: April 2008

AbstractThe effect of rare earth solution (RES) surface treatment of carbon fibers (CFs) on the tensile strength and tribological properties of CF‐reinforced polyimide (CF/PI) composite was investigated. Experimental results revealed that the tensile strength of RES‐treated CFs reinforced PI composite was improved by about 19% compared with that of untreated composite, while 7% improvement was achieved by air oxidation. Compared with the untreated and air‐oxidated CF/PI composite, the RES‐treated composite had the lowest friction coefficient and specific wear rate under given applied load and reciprocating sliding frequency. RES treatment effectively improved the interfacial adhesion between CFs and PI. The strong interfacial adhesion of the composite made CFs not easy to detach from the PI matrix and prevented the rubbing‐off of PI, and accordingly improved the friction and wear properties of the composite. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
The investigation of intumescent flame‐retardant polypropylene using a new macromolecular charring agent polyamide 11
Authors: Liu Yuan , Feng Zhiqiang , Wang Qi 
Published: April 2008

AbstractThis article deals with a new macromolecular charring agent, polyamide 11 (PA11), which is in combination with a small charring agent, pentaerythritol (PER) and a flame retardant, ammonium polyethylene to flame‐retardant polypropylene (PP). When compared with polyamide 6 (PA6), an existing macromolecular charring agent extensively reported, PA11 has longer alkyl segment in its chain unit and shows better compatibility with PP; additionally, with a relatively lower melt point close to that of PP, PA11 can be more effectively compounded with PP in the melt state and better dispersed in PP matrix, thus enhancing the flame retardancy and mechanical properties. Moreover, with certain synergistic effects between PA11 and PER, the system using PA11/PER as composite charring agents showed better charring performance in comparison with the system only using PER. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Preparation and characterization of functionalized carbon nanotubes/poly(phthalazinone ether sulfone ketone)s composites
Authors: Feng Xuebin , Liao Gongxiong , He Wei , Sun Qingmin , Jian Xigao , Du Jinhong 
Published: April 2008

AbstractMultiwalled carbon nanotubes (MWNT) were successfully functionalized with phthalazinone‐containing diamine (DHPZDA) groups by the amidation reaction. The morphologies and structures of the DHPZDA‐functionalized MWNT (MWNT‐DHPZDA) were characterized by scanning electron microscope, Fourier transform infrared, and Raman spectroscopy, revealing that the DHPZDA were covalently attached onto the surface of MWNT, and the weight gain due to the functionalization was determined by thermogravimetric analysis. The MWNT‐DHPZDA/poly(phthalazinone ether sulfone ketone)s (PPESK) composites with different filler content were prepared by the solution‐mixing method. MWNT‐DHPZDA can be uniformly dispersed in the matrix and the strong interfacial adhesion between two constituents was found, which resulted in obvious enhancements of the mechanical properties. For the composite with 1 wt% MWNT‐DHPZDA, the tensile strength and the Young's modulus are 102.1 and 1,974 MPa, about 1.65 and 1.72 times of the pure PPESK, respectively. Conductivity measurements indicate that a typical percolation transition behavior takes place for MWNT‐DHPZDA content in the range from 0.5 to 2 wt%. Additionally, introducing MWNT‐DHPZDA into PPESK is favorable to improvement of the thermal stability. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Synthesis and properties of the amino‐functionalized multiple‐walled carbon nanotubes/polyimide nanocomposites
Authors: Hu Yizhe , Shen Jianfeng , Qin Chen , Wu Liping , Zhang Binbin , Ye Mingxin 
Published: April 2008

AbstractThe 1,6‐hexanediamine‐functionalized multi‐walled carbon nanotubes(a‐MWNTs)/polyimide(PI) nanocomposite films were prepared through in‐situ polymerization followed by mixture casting, evaporation, and thermal imidization. To increase the compatibility of carbon nanotubes with the matrix polyimide, a‐MWNTs was used as the filler. According to the results, a‐MWNTs were homogeneously dispersed in the nanocomposite films. With the incorporation of a‐MWNTs, the mechanical properties of the resultant films were improved due to the strong chemical bonding and interfacial interaction between a‐MWNTs and 4,4′‐oxydiphthalic anhydride(ODPA)/4,4′‐Oxydianiline(ODA) polyimide matrix. The thermal stability of the a‐MWNTs/polyimide nanocomposite was also improved by the addition of a‐MWNTs. The electrical tests showed a percolation threshold at about 0.85 vol% and the electrical properties were increased sharply. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Acute dyspnea in an adolescent girl after physical exertion: A case report and review of the literature
Authors: Yalçın Ebru , Arıyürek Macit 
Published: April 2008

AbstractDyspnea is a common symptom of cardiac and pulmonary diseases. We present a 15‐year‐old girl with acute dyspnea, chest pain, cough, and difficulty in swallowing whose initial diagnosis was psychogenic dyspnea. The etiology of acute dyspnea is discussed and reported cases are reviewed in this case report. Pediatr Pulmonol. 2008; 43:604–606. © 2008 Wiley‐Liss, Inc.
Nasal potential difference in non‐classic cystic fibrosis—long term follow up
Authors: Jaron Ranit , Yaakov Yasmin , Rivlin Joseph , Blau Hannah , Bentur Lea , Yahav Yakov , Kerem Eitan , Bibi Haim , Picard Elie , Wilschanski Michael 
Published: April 2008

AbstractBackgroundNasal potential difference (NPD) measurement is an electrophysiological test that assesses cystic fibrosis transmembrane conductance regulator (CFTR) activity and is a recognized diagnostic tool in CF. The aim of this study is to assess in the long term the role of NPD in patients whose diagnosis is questionable.MethodsWe performed follow up study on 70 patients with questionable CF (QCF) who were divided previously into two groups according to their NPD results: patients who likely have CF (QCF‐CF) (n = 24), and those who likely do not have CF (QCF‐non‐CF) (n = 46).ResultsSixty out of 70 patients were available for study. Sixteen patients in the QCF‐CF group were being followed up at CF Centers as opposed to 1 in the QCF‐non‐CF group (P < 0.01). Seven patients from the QCF‐CF group developed sinusitis during the follow up years compared to none from the QCF‐non‐CF group. During the years of the follow up, 17 QCF‐non‐CF patients were diagnosed with other medical conditions that could explain their previous symptoms. On repeated NPD measurement in the QCF‐CF group, the results were similar to the original test.ConclusionsThis study supports the diagnostic role of NPD measurement. Larger cohort studies are required for confirmation. Pediatr Pulmonol. 2008; 43:545–549. © 2008 Wiley‐Liss, Inc.
Lattices for ab initio protein structure prediction
Authors: Pierri Ciro Leonardo , De Grassi Anna , Turi Antonio 
Published: April 2008

AbstractIn the study of the protein folding problem with ab initio methods, the protein backbone can be built on some periodic lattices. Any vertex of these lattices can be occupied by a “ball,” which can represent the mass center of an amino acid in a simplified coarse‐grained model of the protein. The backbone, at a coarse‐grained level, can be constituted of a No Reverse Self Avoiding Walk, which cannot intersect itself and cannot go back on itself. There is still much debate between those who use lattices to simplify the study of the protein folding problem and those preferring to work by using an off‐lattice approach. Lattices can help to identify the protein tertiary structure in a computational less‐expensive way, than off‐lattice approaches that have to consider a potentially infinite number of possible structures. However, the use of a lattice, constituted of insufficiently accurate direction vectors, constrains the predictive ability of the model. The aim of this study is to perform a systematic screening of 7 known classic and 11 newly proposed lattices in terms of predictive power. The crystal structures of 42 different proteins (14 mainly alpha helical, 14 mainly beta sheet and 14 mixed structure proteins) were compared to the most accurate simulated models for each lattice. This strategy defines a scale of fitness for all the analyzed lattices and demonstrates that an increase in the coordination number and in the degrees of freedom is necessary but not sufficient to reach the best result. Instead, the introduction of a good set of direction vectors, as developed and tested in this study, strongly increases the lattice performance. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Constructing templates for protein structure prediction by simulation of protein folding pathways
Authors: Kifer Ilona , Nussinov Ruth , Wolfson Haim J. 
Published: April 2008

AbstractHow a one‐dimensional protein sequence folds into a specific 3D structure remains a difficult challenge in structural biology. Many computational methods have been developed in an attempt to predict the tertiary structure of the protein; most of these employ approaches that are based on the accumulated knowledge of solved protein structures. Here we introduce a novel and fully automated approach for predicting the 3D structure of a protein that is based on the well accepted notion that protein folding is a hierarchical process. Our algorithm follows the hierarchical model by employing two stages: the first aims to find a match between the sequences of short independently‐folding structural entities and parts of the target sequence and assigns the respective structures. The second assembles these local structural parts into a complete 3D structure, allowing for long‐range interactions between them. We present the results of applying our method to a subset of the targets from CASP6 and CASP7. Our results indicate that for targets with a significant sequence similarity to known structures we are often able to provide predictions that are better than those achieved by two leading servers, and that the most significant improvements in comparison with these methods occur in regions of a gapped structural alignment between the native structure and the closest available structural template. We conclude that in addition to performing well for targets with known homologous structures, our method shows great promise for addressing the more general category of comparative modeling targets, which is our next goal. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Aldrin epoxidation and dihydroisodrin hydroxylation as probes of in vivo and in vitro oxidative metabolic capability of some caterpillars
Authors: Krieger Robert I 
Published: April 2008

AbstractComparative biochemical studies are productive means to study factors that limit both beneficial and harmful effects of chemicals. Reactions such as aldrin epoxidation and dihydroisodrin hydroxylation are valuable assays of oxidative metabolism in scientific studies of chemical biology in insects, subhuman primates and other living things. The tissue distribution of activity in caterpillars may have functional significance. Localization of relatively high concentrations of these cytochrome P450 monooxygenases in gut tissue of lepidoptera may represent an important means to minimize absorption of lipophilic foreign chemicals in food. Some polychlorocycloalkanes permit in vivo and in vitro studies owing to their stability, acceptable toxicity and relatively simple pattern of metabolism. In vivo studies to assess the significance of in vitro findings are feasible with substrates such as aldrin, dihydroisodrin (DHI) and oxidative methylenedioxyphenyl inhibitors such as piperonyl butoxide (PBO) or carbon monoxide. Biphasic dose‐dependent decreased and increased DHI‐OH formation resulted from PBO pretreatment by gut, fat body, head and Malpighian tubule homogenates of cutworms and gut and fat body (the only tissues tested) of cabbage looper Trichplusia ni (Hübner) and black cutworm Agrotis ipsilon (Hüfnagel). The biphasic in vivo responses of caterpillars to PBO are a reminder of the complexity of biochemical and physiological responses of organisms coexposed to chemicals that are classified, often glibly, as toxic substances and metabolic inhibitors and inducers. Knowledge of dose and time relationships demands very careful evaluation in living things in the environment. Copyright © 2008 Society of Chemical Industry
Simulation and design of InGaAsN metal‐semiconductor‐metal photodetectors for long wavelength optical communications
Authors: Tsai Shin‐Li , Wu Jenq‐Shinn , Lin Hung‐Ji , Lin Der‐Yuh , Zheng Jin‐Yao 
Published: April 2008

AbstractOptical properties of InGaAsN/AlGaAs metal‐semi‐conductor‐metal photodetectors (MSM‐PDs) with a modulation‐doped heterostructure operating at the wavelength of 1.3 μm have been simulated by a two‐dimensional device simulator. Simulation results show that the optimized device structure has a 30‐nm‐thick cap layer with Nd = 2×1017 cm–3, a 10‐nm‐thick spacer layer, and 7‐μm‐wide finger spacing to exhibit the largest photocurrent response and shortest decay response time. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of surface preparation and i‐AlGaN thickness on electrical properties of i‐AlGaN/GaN heterostructures
Authors: Sawada T. , Takahashi K. , Imai K. , Suzuki K. , Kimura N. , Kitamori K. 
Published: April 2008

AbstractThe influence of surface preparation and wet‐etching of AlGaN layer on electrical properties of bare i‐AlGaN/GaN and Ni/i‐AlGaN/GaN Schottky samples has been investigated. Hall effect measurements of bare samples indicated that the surface oxide increases 2DEG density, while the thinner the AlGaN layer, the lower the 2DEG density is, accompanied with reduced electron mobility. Theoretical analysis indicated that the former is due to lowering of the surface barrier, while in the latter the 2DEG density changes according to theoretical curve with a constant surface barrier. For Schottky samples, both forward and reverse currents increased with reducing the AlGaN layer, giving smaller effective Schottky barrier height (SBH). The behavior can be well explained by combined leakage currents due to leaky patches and simple tunneling through the surface barrier. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)