bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fast analysis of microwave integrated circuits by use of the inner‐outer flexible GMRES‐FFT method
Authors: Mo L. , Chen R. S. , Rui P. L. , Feng X. P. 
Published: October 2004

AbstractIn this paper, the microstrip circuit is analyzed in terms of the mixed potential integral equation (MPIE) by using the rooftop‐function expansion and the blaze‐function testing technique. The integral equation is solved by the inner‐outer flexible generalized minimal residual fast Fourier transform (FGMRES‐FFT) method. Our numerical calculations show that the FGMRES‐FFT method can converge as high as five times faster than the generalized minimal residual‐fast Fourier transform (GMRES‐FFT) method and 16 times faster than the conjugate gradient‐fast Fourier transform (CG‐FFT) method. Some typical microstrip discontinuities are analyzed and the good results obtained demonstrate the validity of the proposed algorithm. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 409–413, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20485
Bend sensor using an embedded etched fiber Bragg grating
Authors: Yu Yong‐Sen , Zhao Zhi‐Yong , Zhuo Zhong‐Chang , Zheng Wei , Qian Ying , Zhang Yu‐Shu 
Published: October 2004

AbstractWe present a new bend sensor which can measure the curvature using an etched fiber Bragg grating (FBG) embedded into a beam. The reflection power of the grating detected by an optical power meter varies linearly with the curvature of the beam. This sensor is independent of temperature. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 414–417, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20486
A portable phase‐shifting interferometer with optical zoom system
Authors: Gao Zhishan , Zhu Rihong , Chen Lei , Wang Qing , He Yong , Ji Huidong 
Published: October 2004

AbstractThree important parts of a portable phase‐shifting interferometer with optical zoom system are described. The first is a phase‐shifter whose driver is integrated in small size with milli‐voltage resolution and kHz dynamic‐frequency response. Second, a seed‐algorithm is proposed that some spatial points are picked up as seeds, and the wavefronts with obscuration or irregular edges can be retrieved from these seeds as they grow and spread. Third, the measurement of a corner‐cube reflector is given in detail. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 417–419, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20487
Tuning sampled nonlinearly chirped fiber Bragg gratings with adjustable chirp and fixed center wavelength
Authors: Zhao Zhiyong , Zhang Shuang , Yu Yongsen , Zhuo Zhongchang , Zhang Jian , Qian Ying , Zheng Wei , Zhang Yushu 
Published: October 2004

AbstractA simple method for tuning a sampled nonlinearly chirped fiber Bragg grating (SNCFBG) without a center‐wavelength shift is demonstrated experimentally. A uniform sampled fiber Bragg grating (SFBG) is adhered on a bent plastic plate along a precalculated curve. The nonlinear chirp among the SFBG channels is tuned when a displacement is applied to the free end of the plastic plate and the central wavelength of the grating is fixed. The dispersion varies from −996.3 to −117.9 ps/nm in the center channel and the center‐wavelength shift is as small as 0.06 nm in the tuning process. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 432–434, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20493
Compact planar bandpass filter using multisection transformers
Authors: Karmakar Nemai Chandra , Ling Rita Lim Li 
Published: October 2004

AbstractA novel design of multi‐section compact planar bandpass filter has been proposed. The filter uses two back to back three‐section Chebyshev impedance transformers with a coupling gap. The 15 mm by 15 mm filter resonates at 5.28 GHz and yields 6% 3 dB cutoff bandwidth. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 435–437, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20494
A wideband printed dipole antenna with optimized tapered feeding balun for ISM and FWA bands
Authors: Vasiliadis Theodore G. , Vaitsopoulos Evangelos G. , Sergiadis George D. 
Published: October 2004

AbstractThis paper presents a wideband printed dipole‐antenna element. The broad bandwidth is achieved by optimization of the feeding network, which is implemented as a microstrip tapered balun. The design is based on double‐sided flat‐dipole implementation. The prototype antenna exhibits a measured impedance bandwidth of 58% (VSWR < 2), operating over the entire 2.4‐GHz ISM and 3.6‐GHz FWA bands. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 437–441, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20495
Using interpolation and subvoxel modeling to calculate the power density of FDTD‐simulated electromagnetic fields
Authors: Zhao Jianxun , Wei Zhenggang 
Published: October 2004

AbstractFrom the staggered field components provided by the finite‐difference time‐domain (FDTD) method, we use interpolation to obtain six field components at the same location and at the same time instant in order to calculate the power density (PD) of the electromagnetic field (EMF). The subvoxel modeling of the scattering object is also discussed. Comparisons indicate that the joint application of the interpolation and the subvoxel modeling effectively improves the PD precision and significantly reduces the computer memory required to implement the FDTD method. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 441–445, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20496
Shielding effectiveness of a metallic enclosure with multiple apertures
Authors: Feng Chao , Shen Zhongxiang 
Published: October 2004

AbstractIn this paper, we employ the hybrid finite difference–moment method to predict the shielding effectiveness (SE) of a metallic enclosure with multiple apertures. The numerical results for various aperture configurations using the hybrid technique are presented and validated. It is found that a good practice to improve the shielding effectiveness of metallic enclosures is to divide a large aperture into several smaller ones. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 447–450, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20498
A new family of microstrip open‐loop resonator filters for high‐selectivity applications
Authors: Cañete Rebenaque David , Quesada Pereira Fernando D. , Gomez Tornero Jose L. , Alvarez Melcon Alejandro , Guglielmi Marco 
Published: October 2004

AbstractIn this paper, the design of a novel planar narrowband microstrip filter is presented. The structure is designed and manufactured in microstrip technology, and it is formed by set of pairs of resonators of different lengths. The length of one resonator in each pair is adjusted so that a suitable odd resonance is tuned to the center frequency of the filter. The length of the other resonator is adjusted so that the next even resonance is tuned again to the center frequency of the filter. The different path of the signal in each resonator produces a cancellation of energy at a given frequency, therefore implementing a transmission zero in the insertion‐loss response of the filter. First, this paper presents a design example of a single set of resonators (basic unit cell) working at the fifth and sixth resonances. Then, two basic unit cells working at the first and second resonances are first optimized, and then they are cascaded to show how higher‐order filter responses can be implemented. The measured results confirm the theoretical predictions, and validate the new structures for high‐selectivity applications. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 450–455, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20499
Structures of new secofriedelane and friedelane acids from Calophyllum inophyllum of French Polynesia
Authors: Laure F. , Herbette G. , Faure R. , Bianchini J.P. , Raharivelomanana P. , Fogliani B. 
Published: October 2004

AbstractThree new friedelane‐type triterpenoids, 3,4‐secofriedelan‐3,28‐dioic acid (1), 27‐hydroxyacetate canophyllic acid (2) and 3‐oxo‐27‐hydroxyacetate friedelan‐28‐oic acid (3), were isolated from the leaves of Calophyllum inophyllum (Clusiaceae) grown in French Polynesia. Their structures were established by the concerted application of 2D NMR techniques including gs‐COSY, gs‐HMQC and gs‐HMBC. Copyright © 2004 John Wiley & Sons, Ltd.
Influence of the cooling conditions on the temperature and crystallinity profiles generated in a sisal fiber reinforced‐polycaprolactone/starch molded part
Authors: Cyras V. P. , Stefani P. M. , Ruseckaite R. A. , Vázquez A. 
Published: October 2004

AbstractIn this work, we performed the simulation of the temperature and relative degree of crystallinity developed across the thickness of a sisal fiber reinforced‐polycaprolactone/starch (30%SF‐PCL/S) molded part under different cooling conditions. The non‐isothermal kinetic model of Kamal and Chu (13) was used to predict the degree of crystallinity profiles. In order to obtain the temperature profiles, the energy equation was solved by treating the composite as a continuum using mass averaged physical properties. The results indicated that for cooling at a constant wall temperature, gradient‐less crystallinity profiles for a wall temperature of 283 K and thicknesses lower than 10 mm are obtained. On the other hand, when cooling at a constant cooling rate, paired degree of crystallinity pieces can be obtained only for thicknesses lower than 2 mm. The continuum numerical approach used herein has the ability of predicting the optimal cooling cycle for manufacturing thick and crystallinity gradient‐less SF‐PCL/S parts. Polym. Compos. 25:461–469, 2004. © 2004 Society of Plastics Engineers.
Influence of polyethersulfone modification of a tetrafunctional epoxy matrix on the fracture behavior of composite laminates based on woven carbon fibers
Authors: Fernández B. , Arbelaiz A. , Diaz E. , Mondragon I. 
Published: October 2004

AbstractIn this study, the influence of poly(ethersulfone) (PES) as a modifying agent of a tetrafunctional epoxy matrix (TGDDM) on the mechanical behavior of composite laminates based on woven carbon fibers has been investigated. Dynamic mechanical experiments were performed on neat matrix resins and on their corresponding laminate composites. Mode‐I and Mode‐II fracture toughness tests for the bulk matrices and their composites, respectively, and also flexural and short beam shear tests (SBS) were carried out. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to investigate the morphologies obtained. A nanoscopic phase separation was obtained after PES addition, which was not able to stabilize the fracture process, leading, as a consequence, to a poor extent of improvement on fracture toughness properties. Polym. Compos. 25:480–488, 2004. © 2004 Society of Plastics Engineers.
Fatigue of fiber‐reinforced injection molded plastics. I: Stress‐lifetime data
Authors: Wyzgoski Michael G. , Krohn John A. , Novak Glen E. 
Published: October 2004

AbstractGlass‐reinforced nylon 66 polyamide (PA), polybutylene terephthalate (PBT), and polycarbonate (PC) were injection molded in a ribbed plaque. Flat strips, tensile bars, and rib sections were cut from the plaque in the flow and crossflow directions and subsequently fatigue tested under both tensile and flexural loading conditions to obtain conventional fatigue S‐N (stress versus number of cycles to fail) or Wohler curves. Both the fiber alignment and the loading mode strongly influenced the resultant S‐N curve. As expected, longer fatigue life results when the imposed stress is parallel to the flow direction, which in turn parallels the predominant fiber orientation direction. Also, at the same stress level, it was observed that flexural loading resulted in a much longer fatigue life compared to tensile loading. Similar S‐N data were obtained in flexure for different geometries, such as rib or flat cross sections, as long as the local fiber orientation was similar. Attempts to use an empirical relationship to rationalize predicted fatigue data based upon tensile or breaking strength were not successful. Polym. Compos. 25:489–498, 2004. © 2004 Society of Plastics Engineers.
A dual‐scale analysis of macroscopic resin flow in vacuum assisted resin transfer molding
Authors: Kang Moon Koo , Lee Woo Il 
Published: October 2004

AbstractIn Vacuum Assisted Resin Transfer Molding (VARTM) where a sacrificial medium is used to facilitate the resin flow, the velocity of the resin varies drastically between inside the sacrificial medium and inside the fiber preform. Although the thickness‐to‐length ratio of a VARTM product is usually small, a 3‐D analysis is required for analyzing the lead‐lag flow in the two different media. The problem associated with the full 3‐D analysis is the CPU time. A full 3‐D numerical mesh comprising a large number of nodes requires a CPU time impractical on most computer platforms. In this study, a dual‐scale analysis technique was proposed. First, the flow analysis for the entire calculation domain was conducted in 2.5‐D. Using the results of the 2.5‐D calculation, the 3‐D analysis was performed for a small area of special concern. In some numerical examples, the local 3‐D analysis could discover an eccentric flow pattern as well as the lead‐lag flow that would inevitably be neglected in 2.5‐D simulations. The global‐local analysis technique practiced in this study can be used to analyze the intricate flow of resin through non‐uniform media in affordable CPU times. Polym. Compos. 25:510–520, 2004. © 2004 Society of Plastics Engineers.
Quasi‐static behavior of polymer composite flywheel rims
Authors: Chen Jianmin , Gowayed Yasser , Broughton Royall 
Published: October 2004

AbstractIn this work, the correspondence principle is used to relate quasi‐static elastic properties of composite materials to time‐dependent properties of its constituent materials (i.e., fiber and matrix). Application of Prony series combined with the multi‐data fitting method is used to enhance the efficiency of the direct inverse Laplace transform and the calculation of the time‐dependent stiffness matrix. Results show that elastic properties in directions other than fiber‐reinforcement directions have a time‐dependent character. Accelerated time‐dependent deformation studies of two flywheel rim designs for a period equivalent to 31 years show that multi‐direction reinforcement will suffer minimum change of dimension over time compared with hoop reinforcement only. Polym. Compos. 25:527–534, 2004. © 2004 Society of Plastics Engineers.
Nanocomposites of ethylene‐vinyl acetate copolymer (EVA) and organoclay prepared by twin‐screw melt extrusion
Authors: Zhang Farao , Sundararaj Uttandaraman 
Published: October 2004

AbstractPreparation of nanocomposites based on ethylene‐vinyl acetate copolymer (EVA) and organoclay by melt intercalation is described in this paper. Effects of VA content, melt flow index (MFI) and maleation of EVA on melt intercalation were investigated by X‐ray diffraction. The level of intercalation into the organoclay increases greatly as VA content increases from 6 to 12 wt%, but shows minimal change from 12 to 28 wt%. For 28 wt% VA content polymers with MFI from 3 to 150, interlayer expansion exhibited a maximum at MFI = 6. Exfoliated nanocomposites were not obtained for a range of unfunctionalized EVA's of different VA content and MFI. Use of maleated EVA (MEVA) had an obvious improvement on exfoliation of the silicate layers probably due to chemical interaction between the MEVA matrix and silicate layers. FTIR results showed that the MA functionality reacts during processing. Lower clay content favored formation of an exfoliated nanocomposite structure. Exfoliated nanocomposites from MEVA exhibited higher Young's modulus and tensile strength than either pure EVA or intercalated nanocomposites from non‐maleated EVA. Polym. Compos. 25:535–542, 2004. © 2004 Society of Plastics Engineers.
UV aging of poly(propylene)/wood‐fiber composites
Authors: Seldén Ragnar , Nyström Birgitha , Långström Runar 
Published: October 2004

AbstractThe effect of accelerated UV‐aging on properties of PP/wood‐fiber composites has been studied. Plates containing 0, 25 and 50 wt% wood‐fibers were subjected to accelerated UV‐aging in a QUV weatherometer for up to 8 weeks. Stabilization against UV‐degradation was made by adding 3% of a UV stabilizer. The results showed that both the unfilled PP and the PP/wood‐fiber composites displayed good UV resistance with regard to mechanical properties. The color of the PP/wood‐fiber composite plates changed from brown to chalky white at the exposed area because of the formation of a thin, strongly degraded surface layer. Physical and chemical analysis of these surface layers using differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy showed that degradation of the PP matrix had occurred, leading to chemicrystallization and extensive surface cracking. A decrease in PP melting temperature was also noted, due to molecular chain scission and the formation of extraneous groups, such as carbonyls and hydroperoxides. These results indicate that the wood‐fibers act as chromophores when incorporated in the PP matrix. Increasing the fiber content from 25 to 50 wt% increases the rate of degradation of the PP matrix by approximately a factor of two. Polym. Compos. 25:543–553, 2004. © 2004 Society of Plastics Engineers.
Microporous polyurethane/acrylate gel polymer electrolyte obtained by emulsion polymerization
Authors: Ren Tianbin , Ren Jie , Tang Xiaozhen 
Published: October 2004

AbstractA novel polyurethane/acrylate (PUA) porous gel electrolyte was prepared by a new method, emulsion polymerization. Compared with the traditional phase inversion method, the new method can eliminate the pollution from solvent and decrease the cost of production. The swelling properties and morphology of the porous polymer membranes were characterized. The porous membranes, made by emulsion polymerization, could absorb large quantities of electrolyte solution to form porous gel electrolytes. The gel electrolytes have good solvent retention ability and high ionic conductivity. Copyright © 2004 Society of Chemical Industry
Identification and characterization of inosine monophosphate dehydrogenase from Halobacterium salinarum
Authors: Park Soo‐Jin , Joo Won‐A , Choi Jiyeon , Lee So‐Hee , Kim Chan‐Wha 
Published: October 2004

AbstractExtremely halophilic Archaea, Halobacterium salinarum live in hypersaline habitats and maintain an osmotic balance of their cytoplasm by accumulating high concentrations of salt (mainly KCl). Therefore, their enzymes adapted to high NaCl concentrations offer a multitude of acutal or potential applications such as biocatalysts in the presence of high salt concentrations. In this study, the protein expression profile of H. salinarum cultured under different NaCl concentrations (3.5 M, 4.3 M, and 6.0 M) was investigated using two‐dimensional gel electrophoresis (2‐DE). As a result of 2‐DE, the protein spots concentrated in acidic range at pH 3–10 were separated effectively using pH 3.5–4.5 ultrazoom IPG DryStrips. The proteins which proved to be upregulated or downregulated in 2‐DE gel were digested with trypsin and identified with matrix‐assisted laser desorption/ionization‐time of flight (MALDI‐TOF) and electrospray ionization quadrupole (ESI‐Q) TOF‐mass spectrometry. Most proteins were identified as known annotated proteins based on sequence homology and few as unknown hypothetical proteins. Among proteins identified, an enzyme named inosine monophosphate dehydrogenase (IMPDH) was selected based on the possibility of its industrial application. IMPDH gene (1.6 kb fragment) expected to exist in H. salinarum was amplified by polymerase chain reaction (PCR) and expressed in Escherichia coli strain, BL21 (DE3) using a pGEX‐KG vector. Recombinant IMPDH purified from H. salinarum has a higher activity in the presence of salt than in the absence of salt.
Protein biomarkers in the plasma of workers occupationally exposed to polycyclic aromatic hydrocarbons
Authors: Kap‐Soon Noh , Do‐Youn Lee , Hak Cha Jung , Joo Won‐A , Lee Eunil , Chan‐Wha Kim 
Published: October 2004

AbstractPolycyclic aromatic hydrocarbons (PAHs) form a chemical family containing several hundred compounds, including benzo[a]pyrene and pyrene. They are usually produced by the incomplete burning of coal, oil, gas, garbage, or other organic substances like tobacco or charbroiled meat. Exposure to PAH causes tumors, primarily in the lung, the bladder, and the skin. To investigate the differentially expressed proteins resultant from PAH exposure, the protein expression in human plasma was analyzed using two‐dimensional electrophoresis (2‐DE). The plasma exposed to PAH was obtained from 48 waste gas pollution measurers working at an automobile emission inspection center. The 1‐hydroxypryene (1‐OHP) level, which is the urinary PAH metabolite used for evaluation of PAH exposure, was 0.28 µmol/mol creatinine in PAH exposure groups, and 0.078 µmol/mol creatinine in unexposed groups (control, n = 33). A protein upregulated by PAH (putative capacitative calcium entry channel) and five overexpressed proteins (two fibrinogen γ‐A chain precursors, a hemopexin precursor, an albumin precursor, and T‐cell receptor β chain C region) were identified with matrix assisted laser desorption/ionization‐time of flight‐mass spectrometry (MALDI‐TOF‐MS) and confirmed with tandem MS (MS/MS) and Western blotting. The putative capacitative calcium entry channel was partially validated with a laboratory made antibody of a representative peptide fragment in PAH‐exposed human plasma samples.
Kinetics and mechanisms of the reactions of benzoyl derivatives of nucleophiles: dependence of the solvation requirement of the reaction on the structures of the nucleophile and the acyl group
Authors: Seoud Omar A. El , Ferreira Monica , Rodrigues Wagner A. , Ruasse Marie‐Françoise 
Published: October 2004

AbstractThe reactions of two series of benzoyl derivatives of nucleophiles were investigated and the results were compared with those for N‐benzoylimidazole. The general structure is ArCO‐Nu, where Ar = X‐C6H4‐ and/or X2‐C6H3‐; X = 4‐Me, H, 4‐Cl, 4‐CN, 4‐NO2 and X2 = 3,5‐dinitro; Nu = iodosobenzoate, ArCO‐Iba, and phosphate dianion, ArCO‐Phos. Catalytic rate constants, kinetic solvent isotope effects, kinetic substituent effects (Hammett equation) and the dependence of ΔH≠ and ΔS≠ on σX were determined. For ArCO‐Iba, the hydrolysis occurs via two pathways, uncatalyzed (kO) and specific base‐catalyzed (kOH) water attack on the iodine atom of the iodosobenzoate ring. This conclusion is based on theoretical calculations of the partial charges on ArCO‐Iba, and the small ρ values calculated at 25°C, −0.22 and 0.92 for kO and kOH, respectively. The data for the reaction of ArCO‐Phos are consistent with a dissociative transition state, leading to elimination of the metaphosphate monoanion (PO). The dependence of the mechanistic pathway on the nucleophile is discussed. Two results are relevant to the reactions of ArCO‐Iba: (i) moderate to large substituent effects on the activation entropies suggest that solvation of the leaving benzoate anion and desolvation of the entering nucleophile contribute to the OH−‐mediated reaction; (ii) the negative and positive signs of ΔS≠ indicate large differences in solvation of the transition states of the kO and kOH pathways. For the spontaneous decomposition of ArCO‐Phos, sizeable substituent effects on both ΔH≠ and ΔS≠ were observed. This shows the contribution of solvation of the leaving benzoate and substituent‐induced shift of the structure of the transition state. Copyright © 2004 John Wiley & Sons, Ltd.