bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dielectric Resonator Antennas
Authors: Ng H. K. , Leung K. W. 
Published: April 2005

AbstractLinearly and circularly polarized conformal strip‐fed dielectric resonator antennas (DRAs) are studied in this article. In the latter case, a parasitic patch is used to excite a nearly degenerate mode. The hemispherical DRA, excited in its fundamental broadside TE111mode, is used for the demonstration. In the analysis, the mode‐matching method is used to obtain the Green's functions, whereas the method of moments is used to solve for the unknown strip currents. In order to solve the singularity problem of the Green's functions, a recurrence technique is used to evaluate the impedance integrals. This greatly increases the numerical efficiency. Measurements were carried out to verify the calculations, with good results.
Low Temperature Co‐Fired Ceramic (LTCC) Technology in RF and Microwave Engineering
Authors: Wu Ke-Li 
Published: April 2005

AbstractThis article outlines the low‐temperature cofired ceramic (LTCC) technology, from its historic evolvement to the basics of dielectric material properties and manufacturing process with emphasis on the design concept of multilayer LTCC RF and microwave embedded passive devices and modules. A detailed table containing most of commonly seen passive components is provided with layouts of their high‐frequency circuit models (Table 4 in the article).
Left‐Handed Materials for Microwave Devices and Circuits
Authors: Krowne Clifford M. 
Published: April 2005

AbstractIn this article we discuss the use of left‐handed materials or arrangements of materials to produce left‐handed responses to enable the construction of electronic devices and circuits. Attention is directed mainly toward the nonfocusing and nonradiating aspects of left‐handed behavior. Production of these materials, insertion of these materials in structures to produce devices and circuits, and the potential new properties of these electronic components and circuits is covered. The new physics causing the unusual aspects of left‐handed materials is presented. Propagation constants for microwave and millimeter electromagnetic waves will be presented, as well as electromagnetic field distributions in devices using left‐handed materials. Left‐handed devices and circuits, utilizing the physical action of left‐handed materials, will be discussed.
RF/Wireless Packaging
Authors: Pinel Stephane , Tentzeris Manos , Staicnlescu Daniela , Laskar Joy 
Published: April 2005

AbstractThe electronics packaging industry has proliferated to a point where its technology is at least equally—the semiconductor technology it is designed to serve. The increase in silicon complexity and integration has imposed demanding requirements on packaging technology for higher I/O counts, finer lead pitch, enhanced heat dissipation, and high‐speed, reliable interconnects. At the same time, the industry is also driving toward reduced printed‐circuit‐board area and complexity. From the traditional role of a protective mechanical enclosure, the modern package has been transformed into a sophisticated thermal and electrical management platform.Recent advances in high‐frequency packaging indicate a migration from wirebond (where the chip or die is interconnected to the package only on the periphery of the die) to flip‐chip (where the die is interconnected to the package using the entire die area); and from ceramic to organic packages, with cartridge and multichip technologies emerging as key form factors.The RF front‐end module is the core of the complex systems, and its integration poses a great challenge. Considering the characteristics of the RF modules, such as high performance up to 100 GHz; a large number of high‐performance discrete passive components, design flexibility, reconfigurable architecture, low power consumption, compactness, customized product, short time to market, and low cost, the system‐on package (SoP ) approach has emerged as the most effective means to provide a realistic integration solution as opposed to the system‐on‐chip (SoC ) solution. The strength of SoP is based on multilayer technololgy using low‐cost and high‐performance materials.
Smith Chart
Authors: Schwab Leonard M. 
Published: April 2005

Abstract
The Smith chart was routinely used to solve difficult transmission‐line matching problems in a variety of broadcasting, microwave, circuit design, and telecommunication applications. While it has since evolved almost exclusively into a software format, the original paper forms remain a convenient detailed medium for print output of finished work from software implementations of Smith's graphical method.
The essential objective in using the Smith chart is stated simply. An impedance (or equivalent admittance) locus over a frequency range is systematically repositioned on the chart in well‐defined ways by the progressive effects of series or shunt elements, thereby placing the passband portion of the impedance vector in the central area of the chart and the stopband portion at the outer periphery of the chart. The circuit elements commonly used include distributed elements such as transmission lines and quarter‐wave stubs, discrete elements such as inductors and capacitors, and any combination of these and related elements. Resistance elements are seldom intentionally used.
Measurement of Near Fields Using a Modulated Scatterer
Authors: Gardiol Fred 
Published: April 2005

AbstractIn the close vicinity of an electronic device or of an antenna, the electric and magnetic fields often exhibit a complex behavior, and a good knowledge of the resulting field pattern would be a most valuable asset for many practical applications. But when one inserts a probe antenna connected to a receiver, close to the the device, one modifies the filed, because metal locally short‐circuits the tangential electric field components.The modulated scatterer technique provides an indirect approach to determine field components, by introducing a small “scatterer” that does not perturb as much as a receiving probe would. The signal returned by the scatterer is very small, and to detect it one “modulates” the scatterer and then uses coherent detection. The amplitude and the phase of the field components are then determined.
Intermodulation
Authors: Pedro José Carlos 
Published: April 2005

AbstractThis article presents a broad overview of intermodulation distortion (IMD) in microwave and RF circuits and systems. It starts by putting IMD in the context of the linear and nonlinear perturbations of telecommunication systems, to then explain its physical origins and most common theoretical analysis methods and laboratory characterization setups. For that, several active device/system models and analytical and numerical techniques are addressed. Finally, the nonlinear distortion generation mechanisms present in typical microwave small‐signal amplifiers, high‐power amplifiers, and frequency converters are reviewed.
Ultra‐Wideband Radio
Authors: Siwiak Kazimierz 
Published: April 2005

AbstractUltrawideband (UWB) signaling is a modern wireless technique that reuses previously allocated RF bands by spreading the energy thinly in a wide spectrum, thus rendering signals imperceptible in the noise floor of conventional narrowband receivers. There are several methods of generating and radiating UWB signals, including a low‐duty‐cycle UWB implemented as time‐modulated UWB (TM‐UWB), and a high‐duty‐cycle direct‐sequence phase‐coded UWB (DS‐UWB). Even conventional radio techniques such as orthogonal frequency‐division multiplexing (OFDM) have been proposed, based on the “loose” spectrum access rules of the U.S. FCC Report and Order, which legalizes the emissions. Unique ways of coding and positioning the impulses, as in transmitted‐reference delay hopped UWB (TRD‐UWB), can result in the extremely simple UWB radio architectures. Here, the technological basics and performance of time‐position‐coded impulse UWB, the direct‐sequence‐coded UWB, and the transmitted‐reference UWB approaches are compared with conventional radio approaches. Several UWB approaches have been proposed in the IEEE 802 standards arena. Applications of UWB devices are presented and potential uses of UWB are described. Short‐pulse, low‐power techniques have enabled practical through‐the‐wall radars, centimeter precision 3D positioning, and communications capabilities at the high data rates, all with exceptional spatial capacities.
Miniaturized Packaged (Embedded) Antennas for Portable Wireless Devices
Authors: Ali M. 
Published: April 2005

AbstractPackaged (embedded) antennas are becoming more and more in need with the rapid proliferation of wireless communication devices and systems. This include mobile phones, pagers, wireless PDAs, phones with enhanced GPS services, terminals with Bluetooth/WLAN functionalities, and RFID tags for inventory tracking and identification. In this article an overview of miniaturized packaged (embedded) antennas is presented. This includes multiband embedded antennas for mobile phone applications in the 900/1900‐MHz bands, Bluetooth/WLAN in 2.4‐ and 5–6‐GHz bands. Miniaturized planar inverted‐F antennas (PIFAs) are discussed along with wideband monopoles for possible triple‐band applications. Surface‐mount PIFAs, integrated inverted‐F antennas (IFAs), and packaged monopole type radiators are discussed for Bluetooth and WLAN applications. Finally, some future trends in this research area are also discussed.
Electromagnetic Bandgap Assisted Bandpass Filters
Authors: Karmakar Nemai C. , Nurunnabi Mollah Mohammad 
Published: April 2005

AbstractElectromagnetic bandgap structures (EBGSs) are playing a vital role in enhancing the performance of microwave devices. EBG materials are periodic structures, that exhibit wide bandpass and bandrejection properties at microwave frequencies. The introduction of periodic perturbation such as dielectric rods, holes, and patterns in waveguides and PCB substrates has resulted in the development of EBGSs, which are also termed photonic bandgap (PBG) materials.
MIMO Systems for Wireless Communications
Authors: Iyanda Sulyman Ahmed , Ibnkahla Mohamed 
Published: April 2005

AbstractDemands for high‐speed, reliable wireless data communications have increased rapidly. Multiple input–multiple output (MIMO) communication systems have recently been embraced as an effective means to achieve high data rate transmission over wireless channels. Several MIMO signal processing techniques have thus been exploited, each of them aimed at providing high data rate while optimizing various other additional performance criteria. These techniques include spacetime codes, MIMO beamforming, and spatial multiplexing systems among others. In this article, an overview of these MIMO algorithms is presented. Performance improvement of the MIMO communications system over the conventional wireless communications system is then illustrated. Equalization techniques employed in MIMO receivers for transmissions over frequency‐selective channels are then reviewed.
Maxwellian Circuits
Authors: Mei Kenneth K. 
Published: April 2005

AbstractA Maxwellian circuit is defined as a discretized equivalent circuit of a wire structure, the solution of which is the same as that of the Maxwell's equations satisfying the same boundary conditions of the circuit. The theory of Maxwellian circuits is based on the existence and uniqueness theorems of equivalent differential equations of each thin‐wire‐type integral equation, which is derived from Maxwell's equations. In this article, the proofs of the basic theorems are presented, calculations verifying the theory are shown in figures, and related applications are discussed.
A novel process configuration for anaerobic digestion of source‐sorted household waste using hyper‐thermophilic post‐treatment
Authors: Hartmann Hinrich , Ahring Birgitte K. 
Published: April 2005

AbstractA novel reactor configuration was investigated for anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW). An anaerobic hyper‐thermophilic (68°C) reactor R68 was implemented as a post‐treatment step for the effluent of a thermophilic reactor R1 (55°C) in order to enhance hydrolysis of recalcitrant organic matter, improve sanitation and ease the stripping of ammonia from the reactor. The efficiency of the combined system was studied in terms of methane yield, volatile solids (VS) reduction, and volatile fatty acid (VFA) production at different hydraulic retention times (HRT). A single‐stage thermophilic (55°C) reactor R2 was used as control. VS reduction and biogas yield of the combined system was 78–89% and 640–790 mL/g VS, respectively. While the VS reduction in the combined system was up to 7% higher than in the single‐stage treatment, no increase in methane yield was observed. Shifting the HRT of the hyper‐thermophilic reactor from 5 days to 3 days resulted in a drop in the methanogenic activity in the hydrolysis reactor to a minimum. Operation of R68 at HRTs of 24–48 h was sufficient to achieve high VS conversion into VFAs. Removal of pathogens was enhanced by the hyper‐thermophilic post‐treatment. 7% of the ammonia load was removed in the hyper‐thermophilic reactor with a flow of headspace gas through the reactor equivalent to four times the biogas flow produced in reactor R1. © 2005 Wiley Periodicals, Inc.
Electrical Conductivities and Conduction Mechanisms of Perovskite‐Type Na1‐xKxMgF3 (x = 0, 0.1,1) and KZnF3.
Authors: Yoshiasa Akira , Sakamoto Daisuke , Okudera Hiroki , Sugahara Masahiko , Ota Ken'ich , Nakatsuka Akihiko 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Oxidative Transformation of 1,3‐Dioxacycloalkanes Induced by Chlorine Dioxide.
Authors: Abdrakhmanova A. R. , Kabal'nova N. N. , Rol'nik L. Z. , Yagafarova G. G. , Shereshovets V. V. 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Ring‐Opening of Lactones with Enolate Nucleophiles: A Simple Access to Functionalized β‐Ketoesters, β,δ‐Diketoesters and β‐Ketosulfoxides.
Authors: Lanners Steve , Khiri Naima , Solladie Guy , Hanquet Gilles 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis of 1,3‐Enynes via Suzuki‐Type Reaction of Vinylic Tellurides and Potassium Alkynyltrifluoroborate Salts.
Authors: Stefani Helio A. , Cella Rodrigo , Doerr Felipe A. , Pereira Claudio M. P. , Zeni Gilson , Gomes Marlito Jr. 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Stereoselective Synthesis of (E)‐β‐Arylvinyl Bromides by Microwave‐Induced Reaction of anti‐3‐Aryl‐2,3‐dibromopropanoic Acids Using an AgOAc—AcOH System.
Authors: Kuang Chunxiang , Senboku Hisanori , Tokuda Masao 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Three‐Component Reactions of Polynitromethanes with Alkynes. The First Synthesis of gem‐Dinitroaziridines.
Authors: Budynina Ekaterina M. , Averina Elena B. , Ivanova Olga A. , Kuznetsova Tamara S. , Zefirov Nikolai S. 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Iridium Complex‐Catalyzed Intramolecular Ene‐Type Reaction of 1,6‐Enynes Accelerated in Ionic Liquid.
Authors: Shibata Takanori , Yamasaki Mitsunori , Kadowaki Sho , Takagi Kentaro 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Sequential Homobimetallic Catalysis: An Unprecedented Tandem Pd(0)‐Catalyzed Deprotection — Pd(II)‐Catalyzed Heterocyclization Reaction Leading to Benzofurans.
Authors: Gabriele Bartolo , Mancuso Raffaella , Salerno Giuseppe , Veltri Lucia 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
A Novel Biomimetic Route to the 3‐Acyl‐5‐hydroxy‐3‐pyrrolin‐2‐one and 3‐Acyl‐3,4‐epoxy‐5‐hydroxypyrrolidin‐2‐one Ring Systems.
Authors: Snider Barry B. , Neubert Bobbianna J. 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Oxazoles Formation During O‐Alkylation of Isonitroso‐naphthols. X‐Ray Structure of [1,2]Naphthoquinone 1‐[O‐(4‐tert‐Butyl‐benzyl)‐oxime] and 2‐(4‐tert‐Butyl‐phenyl)naphth[1,2‐d]oxazole.
Authors: Astolfi Paola , Carloni Patricia , Castagna Riccardo , Greci Lucedio , Rizzoli Corrado , Stipa Pierluigi 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
3‐Nitrochromene Derivatives as 2π Components in 1,3‐Dipolar Cycloadditions of Azomethine Ylides.
Authors: Nyerges Miklos , Viranyi Andrea , Marth Gabriella , Dancso Andras , Blasko Gabor , Toeke Laszlo 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis and Antimalarial Evaluation of New N1‐(7‐Chloro‐4‐quinolyl)‐1,4‐bis(3‐aminopropyl)piperazine Derivatives.
Authors: Ryckebusch Adina , Debreu‐Fontaine Marie‐Ange , Mouray Elisabeth , Grellier Philippe , Sergheraert Christian , Melnyk Patricia 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
One‐Pot Synthesis of Alkyl Indeno[1,2‐b]quinoxalin‐11‐ylideneacetates under Solvent‐Free Conditions.
Authors: Azizian Javad , Mohammadizadeh Mohammad R. , Karimi Narges , Mohammadi Ali A. , Karimi Ali R. 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis of α‐Isocyano‐α‐alkyl(aryl)acetamides and Their Use in the Multicomponent Synthesis of 5‐Aminooxazole, Pyrrolo[3,4‐b]pyridin‐5‐one and 4,5,6,7‐Tetrahydrofuro[2,3‐c]pyridine.
Authors: Fayol Aude , Housseman Christopher , Sun Xiaowen , Janvier Pierre , Bienayme Hugues , Zhu Jieping 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
One‐Pot Synthesis of Furo[3,2‐c]oxepin‐4‐one Derivatives by the CAN‐Mediated Reaction of tert‐Butyl 2‐(2‐Hydroxytetrahydrofuran‐2‐yl)acetates with Alkenes.
Authors: Kobayashi Kazuhiro , Umakoshi Hironobu , Hayashi Kazutaka , Morikawa Osamu , Konishi Hisatoshi 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Thiosugar Nucleosides. Synthesis and Biological Activity of 1,3,4‐Thiadiazole, Thiazoline and Thiourea Derivatives of 5‐Thio‐D‐Glucose.
Authors: Al‐Masoudi Najim A. , Al‐Soud Yaseen A. , Al‐Masoudi Wasfi A. 
Published: April 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Multiscaling comparative analysis of time series and geophysical phenomena
Authors: Scafetta Nicola , West Bruce J. 
Published: April 2005

AbstractDifferent methods are used to determine the scaling exponents associated with a time series describing a complex dynamical process, such as those observed in geophysical systems. Many of these methods are based on the numerical evaluation of the variance of a diffusion process whose step increments are generated by the data. An alternative method focuses on the direct evaluation of the scaling coefficient of the Shannon entropy of the same diffusion distribution. The combined use of these methods can efficiently distinguish between fractal Gaussian and Lévy‐walk time series and help to discern between alternative underling complex dynamics. © 2005 Wiley Periodicals, Inc. Complexity 10: 51–56, 2005
Attenuated gastropathy but not enteropathy of diclofenac–cholestyramine complex in rats
Authors: Ramírez‐Alcántara Verónica , Castañeda‐Hernández Gilberto , Alan Rampy Bill , Aronson Judith F. , Treinen‐Moslen Mary 
Published: April 2005

AbstractDiclofenac is a nonsteroidal anti‐inflammatory drug (NSAID) widely prescribed for pain and inflammation. Theoretically, the gastrointestinal (GI) complications of diclofenac could be minimized by administering a diclofenac resinate formulation, such as Flotac, where GI mucosal contact with free NSAID is minimized by its complexing with the cholestyramine resin. The objective of the present study was to investigate the influence of cholestyramine co‐treatment on diclofenac enteropathy in fed rats and diclofenac gastropathy in fasted rats. Male Sprague‐Dawley rats were gavaged with diclofenac (50 mg/kg), diclofenac (50 mg/kg) plus cholestyramine (50 mg/kg), or an equivalent amount of Flotac, a 1:1 wt/wt mixture of diclofenac and cholestyramine presently used in human therapeutics in Mexico. Ulceration of the GI tract, serum proteins, and bile salts were assessed at 3, 12, or 24 h. Cholestyramine alone produced no detectable alterations in small intestinal integrity or serum bile salts levels. Fed rats given Flotac or diclofenac plus cholestyramine showed patterns of small intestinal ulceration and serum protein decline that were similar to rats given only diclofenac. Thus, no influence on enteropathy was detected. In contrast, fasted rats given Flotac showed a modest reduction in the number and length of gastric lesions compared to rats given diclofenac. The observed attenuation of gastric lesions with Flotac is consistent with a role for direct cytotoxicity in NSAID gastropathy. Drug Dev. Res. 64:19–27, 2005. © 2005 Wiley‐Liss, Inc.
Design of new potent hypolipidemic agents with the synergistic structural properties of α‐asarone and fibrates
Authors: Zúñiga Clara , Garduño Leticia , del Carmen Cruz María , Salazar María , Pérez‐Pastén Ricardo , Chamorro Germán , Labarrios Fernando , Tamariz Joaquín 
Published: April 2005

AbstractThe series of bioisosteric analogs 9–17 were designed based on the potential pharmacophores of the highly hypolipidemic agents, α‐asarone (1), and fibrates such as clofibrate (2) and fenofibrate (3). These compounds are characterized by their simplicity, in terms of functional group diversity, because most of them are phenoxyacetic acids or their methyl and ethyl esters monosubstituted by an ethyl side‐chain at the ortho, meta, and para positions of the benzene ring. Despite this structural simplicity, these derivatives exhibited potent hypocholesterolemic activity, lowering the mice serum cholesterol and low‐density lipoprotein cholesterol levels up to 40% at the lowest dose of 25 mg/kg. These results supported the concept that the phenoxyacetic frame and the ethyl side‐chain can be considered as potent pharmacophores for the preparation of potential hypocholesterolemic drugs. Drug Dev. Res. 64:28–40, 2005. © 2005 Wiley‐Liss, Inc.
Poly(Arylene Ether Sulfone) Copolymers and Related Systems from Disulfonated Monomer Building Blocks: Synthesis, Characterization, and Performance – A Topical Review
Authors: Harrison W. L. , Hickner M. A. , Kim Y. S. , McGrath J. E. 
Published: April 2005

AbstractResearch and development efforts have been focussed over the last five years towards the preparation of new, but potentially commercially viable low‐cost copolymers for use as proton exchange membrane for fuel cell and other membrane applications.Our primary efforts centered on the direct synthesis of disulfonated copolymersviastep‐polycondensation methods. These novel series of disulfonated copolymers include optionally fluorinated poly(arylene ethers), poly(thioethers), polyimides, polybenzimidazoles, and polybenzoxazoles, as well as multiblock copolymer systems. The first generation of alternative proton exchange membranes (PEMs) has focused on wholly aromatic, disulfonated poly(arylene ether sulfone) random copolymers. Detailed herein are the development and current state of these disulfonated poly(arylene ether sulfone) copolymers and their fuel cell performance in both hydrogen‐air PEMFCs and direct methanol fuel cells (DMFC).
Selenium‐Containing Heterocycles from Isoselenocyanates: Cycloaddition of Carbodiimides to Selenazetidines
Authors: Sommen Geoffroy L. , Linden Anthony , Heimgartner Heinz 
Published: April 2005

AbstractThe reactions of isoselenocyanates with carbodiimides in refluxing hexane afforded 1,3‐selenazetidine‐2,4‐diimines 3a–3h by a [2+2] cycloaddition in moderate‐to‐good yields. The molecular structure of 3a has been established by X‐ray crystallography.