bluuebunny/crossref_metadata_2025_split huggingface dataset:
MNM‐A novel technique for iterative solution of matrix equation arising in the method‐of‐moments formulation
Authors: Mittra Raj , Prakash V. V. S. , Ma Ji‐Fu , Yeo Junho , Huang Neng‐Tien , Kwon Soon Jae 
Published: August 2002

AbstractThis article introduces a simple and efficient technique for generating the initial guess for iterative solutions of a large dense system of linear equations arising in the method‐of‐moments (MoM) formulation of electromagnetic (EM) problems. The proposed approach is based on an extrapolation of the solution vector from those generated at previous frequencies. The extrapolated solution is further refined, if required, by using the conjugate gradient (CG) technique. Questions regarding the accuracy of the solution, as well as its dependency on the stopping criterion and the frequency step size, have been investigated for a large class of EM problems, and representative results are presented. The superiority of the present technique over existing approaches for generating the initial estimate of the solution is demonstrated. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 74–78, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10243
A comparison of different approaches for the simulation of nonlinear transmission lines
Authors: Fernández M. , Martín F. , Steenson P. , Mélique X. , Oistein A. , Oriols X. , Vanbésien O. , García‐García J. , Miles R. , Lippens D. 
Published: August 2002

AbstractIn this work, a detailed analysis of two different approaches to the simulation of nonlinear transmission lines (NLTLs) is presented. Distributed and lumped‐element models have been compared, and it has been shown that the latter (and simpler) approach provides a good description of NLTL behavior when the per‐section capacitance of the line is smaller than the lumped nonlinear capacitance. Filtering aspects of NLTLs under large‐signal driving conditions have been studied with the use of a harmonic balance simulation that avoids the need to linearize the circuit. This is the first time that this powerful simulation tool has been used to study the transmission properties of NLTLs. The results are compared to those obtained by means of a conventional small‐signal S‐parameter simulation and effects related to large‐signal driving conditions, such as the influence of the input power level and the degree of nonlinearity, are presented. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 134–136, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10253
Detection of targets in continuous random media: A numerical study using the angular correlation function
Authors: Moss C. D. , Teixeira F. L. , Kong J. A. 
Published: August 2002

AbstractA three‐dimensional (3D) finite‐difference–time‐domain (FDTD) scheme is used to study the angular correlation function (ACF) of the scattered fields from continuous random media (volume) with and without a target object present. The FDTD simulations are employed to examine the effectiveness of ACF for object detection in the presence of volumetric clutter. It is shown that the frequency‐averaged ACF can be as much as 10‐dB greater when a target object is present for situations where the target is undetectable by direct examination of the radar cross section only. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 242–247, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10287
Design of an ultraviolet filter based on photonic band‐gap materials
Authors: Srivastava Sanjeev K. , Ojha S. P. , Ramesh K. S. 
Published: August 2002

AbstractThe fabrication of a bandpass filter in the ultraviolet region of the electromagnetic spectrum with the use of photonic band‐gap (PBG) materials is presented on the basis of the Kronig–Penny model in the band theory of solids. The periodic structure of different dielectrics and semiconductor materials in rectangular symmetry is considered. Illustrative diagrams are presented in order of allowed and forbidden bands of wavelengths. The filter can also act as an efficient ultraviolet monochromator by the appropriate selection of the controlling parameters. The anomalous dispersion behavior of glass and zinc sulphide (ZnS) is discussed. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 308–314, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10304
Highly efficient finite‐difference schemes for structures of nonrectangular cross‐section
Authors: Djurdjevic D. Z. , Sewell P. , Benson T. M. , Vukovic A. 
Published: August 2002

AbstractA novel finite‐difference beam‐propagation method (FD‐BPM) algorithm for the analysis of photonics structures with sloped sides in the transverse plane is presented. By introducing nonorthogonal coordinate systems in the transverse plane, the staircasing effects inherent when one is modeling with a rectangular mesh are eliminated, and accuracy is substantially improved. The algorithm is tested in the analysis of sloped rib waveguides. The results obtained confirm the accuracy and high efficiency of the new algorithm. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 401–407, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10335
New‐configuration wideband single‐axis and dual‐axis planar monopulse comparators
Authors: Revankar U. K. , Beenamole K. S. 
Published: August 2002

AbstractNovel configurations of single‐axis and two‐axis planar monopulse comparators are presented, providing a very close amplitude and phase matching over a wide bandwidth with an application in broadband monopulse radar systems. Unlike the conventional monopulse comparators, the present unique design features have offered a very good return loss as well as amplitude and phase imbalance of ± 0.1 dB and ± 1.5° over a large bandwidth (>15%) in L band, for two‐axis monopulse comparators. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 427–430, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10341
A new type of slow‐wave 1‐D PBG microstrip structure without etching in the ground plane for filter and other applications
Authors: Nesic Dusan 
Published: August 2002

AbstractA new type of one‐dimensional (1D) photonic bandgap (PBG) microstrip slow‐wave structure applied for filter is presented. The proposed filter exhibits remarkable slow‐wave and low‐pass characteristics. It is formed without etching in the ground plane, only by modification of the microstrip line. The miniature low‐pass filter with three cells is simulated, realized, and measured. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 440–443, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10345
Reflection and transmission ellipsometry data analysis for measuring the complex permittivity of a single‐layer material at microwave frequencies
Authors: Sagnard F. , Seetharamdoo D. , Le Glaunec V. 
Published: August 2002

AbstractFor in situ measurement of the complex permittivity of planar materials, a free‐space system based on reflection or transmission ellipsometry has been developed and extended to microwave frequencies. Different angles of incidence were studied in the range [35–50°]. Original numerical methods based on contour‐line charts and least‐square optimization have been developed. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 443–448, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10346
Electromagnetic‐wave diffraction by a chiral layer with a reflecting grating of dielectric‐filled grooves
Authors: Kusaykin Oleksandr P. , Poyedynchuk Anatoly Ye. 
Published: August 2002

AbstractA diffraction problem is solved for a plane E‐ or H‐polarized wave incident on a chiral layer placed over a reflecting grating of rectangular grooves cut in a perfectly conducting metal plane. The approach uses decomposition and generalized scattering matrix methods. The phenomenon of quasi‐complete cross‐polarization conversion of waves with large telescopicity coefficient is shown. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 462–465, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10351
A new instantaneous model of MESFET and HEMT devices for large‐signal circuit design
Authors: Cicolani Maurizio , Di Martino Alberto , D'Innocenzo Silvio , Pisa Stefano , Tommasino Pasquale , Trifiletti Alessandro 
Published: August 2002

AbstractA nonlinear lumped‐element model of MESFET and HEMT devices whose parameters are empirical functions of instantaneous voltages at the controlling internal nodes has been developed and used to design an X‐band hybrid amplifier. Excellent agreement between measurements and simulated performance in small‐signal and nonlinear power characteristics has been obtained. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 187–190, 2001.
Large‐signal modulation response of 1.3 μm InGaAsP MQW lasers
Authors: Torres Pereira J. M. 
Published: August 2002

AbstractThe large‐signal modulation response of a 1.3 μm InGaAsP four‐well laser of the Fabry–Perot type is investigated when the input signal is either a sinusoidal or a square wave. The time evolution of the photon density is obtained by the numerical solution of the rate equations for several amplitude and frequency values of the input signal. The output photon density is very similar for the two input signal types, except at low frequencies. The normalized resonance frequency is seen to behave better when the input signal is sinusoidal and nonlinear gain saturation effects take place. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 375–378, 2001.
10 GHz GaAs monolithic twin‐dipole antenna FET mixer
Authors: Meng C. C. , Deng K. L. , Lee H. D. , Lu S. S. , Wang H. 
Published: August 2002

AbstractThe first fully monolithic X‐band twin‐dipole antenna mixer consisting of a uniplanar twin‐dipole antenna and a GaAs MESFET single‐gate mixer on the same GaAs substrate fabricated by monolithic microwave integrated‐circuit technology (MMIC) is reported. The total chip size is 5×5 mm2. This circuit received an RF signal of 10 GHz, and down‐converted it to an IF signal of 1 GHz with a conversion loss of 22 dB. The experimental results demonstrate that this topology has potential applications for future low‐cost millimeter‐wave receivers for smart munitions seekers and automotive‐collision‐avoidance radars. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 436–438, 2001.
Frequency‐selective loading for a transmitting active integrated antenna
Authors: Ertürk V. B. , Rojas R. G. , Roblin P. 
Published: August 2002

AbstractA simple frequency‐selective load in the form of a compensating network is attached to an oscillator‐type transmitting active integrated antenna (AIA) to suppress undesired low‐frequency oscillations and to improve the robustness of the oscillator. Although the input impedance of the active device (transistor) remains unchanged at the upper frequencies, it changes drastically at the lower frequencies. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 3–5, 2001.
Operating wavelength of erbium‐doped fiber‐ring laser
Authors: Kamil Abd‐Rahman M. , Selvakennedy S. , Poopalan P. , Ahmad Harith 
Published: August 2002

AbstractThe erbium‐doped fiber ring laser (EDFL) exhibits a wavelength shift that results from the variation of its intracavity parameters, namely, the output‐coupler reflectivity (R), active fiber length (L), and optical losses (α) in the resonant cavity. A simple and fast technique for predicting the operating wavelength of an EDFL is deduced. The operating wavelength shifts from ∼1530 to ∼1560 nm for higher values of R, longer L, and/or lower α, and vice versa. Data from numerical simulations show a good comparison with the experimental results. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 105–107, 2001.
A novel interpretation of transducer power gain by optical analogy
Authors: Pan Hsuan‐Yu , Tu Hsing‐Yuan , Lu Shey‐Shi , Meng C. C. 
Published: August 2002

AbstractA novel interpretation of transducer power gain (GT) is presented by optical analogy. By employing scattering parameters of the input/output matching network and the transistor, we have developed a simple method to derive GT. In addition to simplicity, our theory also has the advantage of giving the physical meaning for each term of the formula of GT. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 124–126, 2001.
Improvement of modulation/switching performances by using a two‐section semiconductor optical amplifier
Authors: Li Hong Wu , Rampone Thierry , Guegan Mikael 
Published: August 2002

AbstractBy optimizing the carrier distribution along the longitudinal axis of a two‐section semiconductor optical amplifier (SOA), we have improved the modulation/switching performances (modulation index and efficiency, switching contrast) with respect to those of a single‐section component. The modulation efficiency has been raised by up to 137%. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 126–129, 2001.
BW media—media with negative parameters, capable of supporting backward waves
Authors: Lindell I. V. , Tretyakov S. A. , Nikoskinen K. I. , Ilvonen S. 
Published: August 2002

AbstractBoth isotropic and uniaxially anisotropic media capable of supporting backward waves are reviewed. Such an effect recently has been of great interest, and certain man‐made composite media have been introduced under the names “media with negative refraction factor” or “left‐handed materials,” effective in a certain band of microwaves. Neither of these names appears to be well founded, and “backward‐wave medium” (or BW medium) is suggested instead. It is shown that, at an interface of a regular and a BW medium, Snell's law does not imply a negative refraction factor. However, the refraction is anomalous in the sense that the transmitted plane wave is a backward wave with a Poynting vector and a wave vector pointing in opposite lateral directions. The significance of the Zenneck wave and guided modes in a cylindrical guide made of BW medium is discussed. Finally, the BW property is extended to uniaxially anisotropic media, and its occurrence is studied for different value combinations of its medium parameters. It is shown that a lateral backward wave can arise when a plane wave is transmitted through an interface when one of the four parameters of the uniaxial medium is negative. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 129–133, 2001.
Analysis of a circular chiral ferrite dielectric waveguide
Authors: Zhou Haixin , Zhang Keqian 
Published: August 2002

AbstractThe eigenequation of a circular chiral ferrite dielectric waveguide is derived. The effects of chiralities in the core and cladding on the cutoff, the dispersion characteristics, and the field distributions are investigated. The results show that, not only the cutoff frequencies, but also the dispersion curves of HE and EH modes with the same mode number separate, and the chiralities in the core and cladding have different effects on the cutoff and dispersion characteristics. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 143–146, 2001.
Lumbar puncture in pediatric oncology: Conscious sedation vs. general anesthesia
Authors: Ljungman Gustaf , Gordh Torsten , Sörensen Stefan , Kreuger Anders 
Published: August 2002

AbstractBackgroundLumbar punctures (LP) generally have been performed with conscious sedation (CS) but are increasingly performed using general anesthesia (GA) owing to the belief that this is less distressing. The aim of this study was to compare these two methods concerning distress, discomfort, pain, well‐being and security after the LP, and problems with the LP.ProcedureTwenty‐five children with cancer participated in this prospective, randomized, crossover study. Children, parents, and nurses completed a visual analogue scale questionnaire to evaluate the efficacy of CS and GA. In addition, sedation and anesthesia protocols were reviewed.ResultsThe two methods seemed to be equivalent concerning distress, discomfort, pain, well‐being and security after the procedure, and procedure problems. Most children (80%), parents (66%), and nurses (58%) preferred LP in CS. However, the LP was not performed in CS in five cases because the child did not cooperate. Younger children less often preferred CS.ConclusionsOutcomes for CS and GA in LP were similar. Although there were failures with the CS model, most preferred it to GA. LP in CS also saved time and medical resources. An alternative approach would be to have a pediatric anesthesiologist available at the oncology ward for these elective LPs to provide the sedation or anesthesia required by each individual. Med. Pediatr. Oncol. 36:372–379, 2001. © 2001 Wiley‐Liss, Inc.
Screening for Wilms tumor and hepatoblastoma in children with Beckwith‐Wiedemann syndromes: A cost‐effective model*
Authors: McNeil D. Elizabeth , Brown Martin , Ching Alex , DeBaun Michael R. 
Published: August 2002

AbstractBackgroundWe undertook a cost‐benefit analysis of screening for Wilms tumor and hepatoblastoma in children with Beckwith‐Wiedemann syndrome (BWS), a known cancer predisposition syndrome. The purpose of this analysis was twofold: first, to assess whether screening in children with BWS has the potential to be cost‐effective; second, if screening appears to be cost‐effective, to determine which parameters would be most important to assess if a screening trial were initiated.ProceduresWe used data from the BWS registry at the National Cancer Institute, the National Wilms Tumor Study (NWTS), and large published series to model events for two hypothetical cohorts of 1,000 infants born with BWS. One hypothetical cohort was screened for cancer until a predetermined age, representing the base case. The other cohort was unscreened. For our base case, we assumed: (a) sonography examinations three times yearly (triannually) from birth until 7 years of age; (b) screening would result in one stage shift downward at diagnosis for Wilms tumor and hepatoblastoma; (c) 100% sensitivity and 95% specificity for detecting clinical stage I Wilms tumor and hepatoblastoma; (d) a 3% discount rate; (e) a false positive result cost of $402. We estimated mortality rates based on published Wilms tumor and hepatoblastoma stage specific survival.ResultsUsing the base case, screening a child with BWS from birth until 4 years of age results in a cost per life year saved of $9,642 while continuing until 7 years of age results in a cost per life‐year saved of $14,740. When variables such as cost of screening examination, discount rate, and effectiveness of screening were varied based on high and low estimates, the incremental cost per life‐year saved for screening up until age four remained comparable to acceptable population based cancer screening ranges (< $50,000 per life year saved).ConclusionsUnder our model's assumptions, abdominal sonography examinations in children with BWS represent a reasonable strategy for a cancer screening program. A cancer screening trial is warranted to determine if, when, and how often children with BWS should be screened and to determine cost‐effectiveness in clinical practice. Med Pediatr Oncol 2001;37:349–356. Published 2001 Wiley‐Liss, Inc.
Temperature dependence of proton–proton residual dipolar couplings in adenosine dissolved in charged phospholipid bicelles. Application of a two‐dimensional selective refocusing method
Authors: Krajewski Piotr , Bardet Michel 
Published: August 2002

Abstract1H NMR spectra of nucleoside adenosine were recorded in 7.5% (w/v) DMPC/DHPC bicelles doped with CTAB. Despite the small size of adenosine in comparison with the distances between discoidal bicelles, intramolecular 1H,1H residual dipolar couplings D were observed at 29.5–38°C. The absolute values of 1H,1H spin interactions Δ (sum of J‐ and D‐couplings) were measured selectively by a series of 2D SERF experiments as a function of temperature. At lower temperatures dipolar couplings are scaled down, which leads to simplification of the 1H NMR spectra. For some pairs of protons, which are simultaneously J‐ and D‐coupled, the exact values of D can be determined from temperature dependence of Δ. Copyright © 2002 John Wiley & Sons, Ltd.
Structural elucidation and complete assignment of a novel class of sulfonamides: bridgehead tricyclic sultams
Authors: Jolivet Catherine , Long Daniel D. , Dahl Russel S. , Termin Andreas P. 
Published: August 2002

AbstractEndocyclic sulfonamide templates bearing both an exocyclic ketone function and an internal olefin underwent reaction with a variety of hydroxylamines to effect an intramolecular nitrone–olefin cycloaddition to afford a new class of compounds suitable for derivatization by high‐throughput medicinal chemistry. Structural elucidation via complete assignment of the 1H and 13C NMR spectra of this new class of compounds was achieved using gradient‐COSY, gradient heteronuclear multiple quantum‐coherence spectroscopy and gradient heteronuclear multiple bond correlation spectroscopy. Additionally, double pulsed field gradient spin echo–nuclear Overhauser effect experiments were carried out in order to study the spatial conformation of this new type of molecule and assess the stereo‐ and regio‐selectivity of the chemical transformation. The unequivocal molecular framework and structural conformation was confirmed by X‐ray diffraction. Copyright © 2002 John Wiley & Sons, Ltd.
35Cl NQR studies of 1‐chloro‐2,4‐dinitrobenzene and 1,2‐dichloro‐3‐nitrobenzene as a function of pressure and temperature
Authors: Srinivas Jandhyala , Subramanian Raman K. , Ramesh Keralapura P. , Ramakrishna Jandhyala , S. Suresh Kalkunte , Raghavendra Rao Chdaghatta 
Published: August 2002

AbstractThe temperature and pressure dependences of 35Cl nuclear quadrupole resonance (NQR) frequency and spin–lattice relaxation time (T1) were investigated for 1‐chloro‐2,4‐dinitrobenzene and 1,2‐dichloro‐3‐nitrobenzene. T1 was measured in the temperature range 77–300 K. Furthermore, the NQR frequency (ν) and T1 for these compounds were measured as a function of pressure up to 5.1 kbar at 300 K. Relaxation was found to be due to the torsional motion of the molecule and the reorientation motion of the nitro group. By analysing the temperature dependence of T1, the activation energy for the reorientation motion of the nitro group was obtained. The temperature dependence of the average torsional lifetimes of the molecules and the transition probabilities W1 and W2 for the Δm = ±1 and Δm = ±2 transitions, were also obtained. Both compounds showed a non‐linear variation of NQR frequency with pressure. The pressure coefficients were observed to be positive. A thermodynamic analysis of the data was carried out to determine the constant‐volume temperature coefficients of the NQR frequency. The spin–lattice relaxation time T1 for both the compounds was found to be weakly dependent on pressure, showing that the relaxation is mainly due to the torsional motions. Copyright © 2002 John Wiley & Sons, Ltd.
EPR study of radicals generated from bioactive S‐nitrosothiols and related thiols
Authors: Jin Jing , Wu Longmin , Zhang Ziyi 
Published: August 2002

AbstractThermal or photolytic reactions of bioactive S‐nitrosothiols and related thiols in the presence of radical generators in deaerated DMSO or aqueous solutions under argon or saturated with nitric oxide (NO) produced nitroxides and an oxyaminyl radical, which were well characterized by EPR spectra. Nitroxides containing a thiyl substituent were obtained. Possible mechanisms are proposed. Bioactive S‐nitrosothiols such as S‐nitrosoglutathione, S‐nitroso‐N‐acetylpenicillamine and related thiols such as glutathione and N‐acetylpenicillamine were used for the investigation. Radical generators utilized as transient radical sources were 2,2′‐azobisisobutyronitrile, 2,2′‐azobis(2‐methylpropionamidine) dihydrochloride, tert‐butyl peroxide and benzoyl peroxide. Copyright © 2002 John Wiley & Sons, Ltd.