bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultra wideband terahertz absorbers
Authors: Dubey Ashish , Shami T.C. , Bhasker Rao K. U. , Prabhu S. S. 
Published: April 2011

AbstractMost of the recent research on electromagnetic absorbers at terahertz (THz) frequencies is focused on metamaterials based absorber, which provides high absorptivity of electromagnetic (em) radiations in narrow frequency band and tailoring of em response of materials. Under this work, we have also attempted the same problem with different approach, i.e., by using combination of different materials in uniform layered configuration system. Result obtained shows em absorption of 10–20 dB in the lower and higher side of measured spectrum and high absorption of 20–30 dB in central part, i.e., from 1 to 2 THz. Materials with such broadband absorptivity find numerous military and civilian applications. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26059
An F‐shaped printed monopole antenna for dual‐band RFID and WLAN applications
Authors: Panda Jyoti Ranjan , Kshetrimayum Rakhesh Singh 
Published: April 2011

AbstractA simple microstrip fed printed monopole antenna for the radio frequency identification (RFID) and wireless local area network (WLAN) is presented.The antenna has two different resonant current paths (forming an F‐shaped structure) that support two resonances at 2.44 and 5.18 GHz, which are reserved for RFID and WLAN applications, respectively. Effectively omnidirectional radiation pattern and large impedance bandwidth has been observed both from simulation and experimental results. Impedance bandwidth for center frequency of 2.44 and 5.18 GHz are 0.65 GHz (2.12–2.77 GHz) and 0.59 GHz (4.91–5.50 GHz), respectively. The proposed antenna is simple in design and compact in size; providing broadband impedance matching, consistent omnidirectional radiation patterns and appropriate gain characteristics (>1.5dBi) in the RFID and WLAN frequency regions. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26060
On combating deep fades due to ground reflection in point‐to‐point WiMAX communications
Authors: Serhal Dina , Reynaud Sébastien , Chantalat Régis , Hajj Mohamad , Jecko Bernard , Mońedìere Thierry 
Published: April 2011

AbstractIn point‐to‐point wireless communications, the re‐ ceived signal may experience deep fading due to different propa‐ gation phenomena. In this paper, we deal specifically with ground reflection and show how it affects the system communication. As application, we consider the example of point‐to‐point WiMAX communications between base stations (BSs) and trains. The fading problem is mainly due to the fact that both direct and reflected rays are located in the main lobe of the base station antenna and then the correspondant fields have almost the same amplitude. In this paper, we propose several efficient solutions in order to overcome the fading problem. These solutions perform different techniques based, first, on modifying the shape of the main lobe of the BS antenna in order to decrease the magnitude of the ground reflected field, and second, on modifying the antennas polarization. In order to support our propositions, a large set of simulation results is reported and discussed. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26063
A 0.35‐μm CMOS frequency divider implemented with the waffle injection MOSFET
Authors: Jang Sheng‐Lyang , Cheng Ching‐Lun , Chang Chia‐Wei , Juang Miin‐Horng 
Published: April 2011

AbstractThis letter proposes a CMOS injection‐locked frequency divider (ILFD) fabricated in a 0.35‐μm CMOS process.The ILFD circuit is realized with a cross‐coupled CMOS LC‐tank oscillator, and the external injection is carried out through the gate of a waffle MOSFET. The self‐oscillating ILFD is injection‐locked by second‐/fourth‐harmonic input to obtain the division order of two/four. Measurement results show that at the supply voltage of 0.9 V and at the incident power of 0 dBm, the locking range is from the incident frequency 4.25 to 6.35 GHz in the divide‐by‐2 mode. The locking range is from the incident frequency 10.75 to 11.25 GHz in the divide‐by‐4 mode. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26064
Cost‐effective all‐semiconductor 4 × 40 Gbit/s transmission in the 1310‐nm wavelength domain
Authors: Turkiewicz Jaroslaw 
Published: April 2011

AbstractError‐free transmission of 4 × 40 Gbit/s over 50 km of standard single mode fiber in the 1310‐nm wavelength domain is demonstrated. The obtained results prove applicability of the 1310‐nm wavelength domain to support the cost‐effective medium range high capacity transmission systems, e.g., future 400 Gbit/s Ethernet standard. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26065
Bandwidth enhancement of a U‐slot patch antenna using dual‐band frequency‐selective surface with double rectangular ring elements
Authors: Chen Hsing‐Yi , Tao Yu 
Published: April 2011

AbstractA design strategy using a dual‐band frequency‐selective surface (FSS) consisting of double rectangular ring elements to improve the bandwidth and gain and to optimize the onsets of two operating frequencies for a U‐slot patch antenna is presented.After implanting the FSS in the U‐slot patch antenna, it was found that the bandwidths have been improved from 3.14% to 5.51% and 5.48% to 7.48% at resonant frequencies 2.45 and 5.8 GHz, respectively. It was also found that the antenna gain and the onset of operating frequency have been improved for Bluetooth and wireless local area network (WLAN) applications. The U‐slot patch antenna implanted with a FSS consisting of double rectangular ring elements is capable of dual‐band operations at 2.45 and 5.8 GHz. The radiation patterns are satisfied at these dual bands. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26066
Active V‐band modulated backscatter tag
Authors: Cantú Horacio I. , Cumming David R. S. , Drysdale Timothy D. 
Published: April 2011

AbstractWe report the measurement of modulated backscatter produced by a Schottky diode and a printed patch antenna array at V‐band (58.75 GHz). The tag was fabricated on a liquid crystalline polymer substrate that is used as the dielectric film and as a carrier for the diode that is wire bonded to the surface of the array. An inexpensive commercial V‐band transceiver chipset was successfully used to detect modulated backscatter when the diode was switched at kHz frequencies, demonstrating that the effect is strong enough to be used in commercial applications requiring lightweight, wearable transponders. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26067
Simultaneous measurement of force and temperature with a single FBG partially encapsulated with a metal cannula
Authors: Yang Zhangcheng , Xu Hanfeng , Ni Kai , Dong Xingyong 
Published: April 2011

AbstractA simple sensor head based on a single fiber Bragg grating (FBG), which was partially encapsulated by using a metal cannula, has been proposed and demonstrated for simultaneous measurement of force and temperature.Because of the partial encapsulation, the reflection peak of the FBG split into two, corresponding to the two grating halves, when the grating was stretched or the temperature was changed. The two peaks respond differently to force and temperature change so that simultaneous measurement of force and temperature has been realized by measuring wavelengths of the two peaks. Experimental results show that the achieved resolutions, limited by the wavelength resolution, 0.01 nm, of the used optical spectrum analyzer, are 0.007 N and 0.45°C for force and temperature measurements, respectively. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26069
Study on UWB and SWB planar slot antennas with different stub shapes
Authors: Barbarino Sebastiano , Consoli Fabrizio 
Published: April 2011

AbstractThe detailed study of UWB and SWB planar circular slot antennas is here described. They are realized on a εr = 2.33 substrate, and have stub of different shapes. The comparison among the structures is performed in terms of both impedance matching and radiation features at different frequencies. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26076
Impedance and complex power of radiating elements under electromagnetic source transformation
Authors: Allen Jeffery W. , Steyskal Hans , Smith David R. 
Published: April 2011

AbstractTransformation optics is a methodology that has proven useful in the design of complex media used to alter and control electromagnetic waves in either passive space or regions that contain source distributions. Recently it has been shown that the application of source transformations can reshape field radiation patterns corresponding to arbitrarily shaped sources. In the accompanying numerical confirmations, the effect of source transformations on fundamental quantities that are critical to the design and evaluation of antenna based systems‐‐such as complex power and impedance, remain unexplored. In this paper, we present results of theoretical analysis as well as full wave finite element simulations, proving that the complex power and impedance associated with an electromagnetic source are not changed by source transformation methods. These results open the door to the application of source transformations for the design of practical antenna based systems, such as conformal and phased array antenna design. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26077
The tunable defect modes in the comb‐like photonic crystals
Authors: Tong Yuanwei , Zhang Yewen 
Published: April 2011

AbstractA tunable defect mode with a voltage tuning mechanical is demonstrated. A varactor has been introduced into a 1D comb‐like photonic crystal and a defect mode occurs in the band gap. Frequency of the defect modes are controlled by the reverse bias voltage applied to the varactor. The defect peak in the transmission spectrum shifts towards high frequency as the reverse bias voltage increases. The simulating results agree well with the experimental results. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26080
Modified LINC transmitter using efficient parallel amplification scheme
Authors: Liu Rui , Schreurs Dominique , De Raedt Walter , Mertens Robert 
Published: April 2011

AbstractA modified linear amplification with nonlinear component (LINC) transmitter is presented using a novel power combination scheme.By using multiple LINC sections in parallel with a compact adaptive power combining network, the output power of power amplifiers can be boosted, together with obtaining higher efficiency over a large power back‐off region. Compared to existing designs, no gate bias adaptation is needed and efficiency can be further improved. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26086
Fiber length compensated transmission of 2998.01 MHz RF signal with femtosecond precision
Authors: Tratnik Jurij , Pavlovic Leon , Batagelj Bostjan , Lemut Primoz , Ritosa Patrik , Ferianis Mario , Vidmar Matjaz 
Published: April 2011

AbstractAn electro‐optical RF‐clock‐distribution system for 2998.01 MHz is presented. An added timing jitter of 5 fsRMS and a clock drift of 9.5 fsRMS over 24 h have been measured. The RF signal is distributed through a transmitter–receiver topology as intensity modulation on a CW laser at 1550 nm. Temperature‐induced fiber group‐delay variations are compensated by adjusting the wavelength of the laser and making use of the fiber chromatic dispersion. The system uses standard, commercially‐available telecommunication optical components. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26087
Lasing wavelength shift of ASE‐injected wavelength‐locked F‐P LD in WDM‐PON
Authors: Meng Hongyun , Zhang Guanbin , Wang Wei , Lee Chang‐Hee 
Published: April 2011

AbstractThe lasing wavelength shift characteristics of amplified spontaneous emission (ASE)‐injected wavelength‐locked Fabry‐Perot laser‐diodes used in the wavelength division multiplexed passive optical network are studied. The lasing wavelength shift at different injected‐ASE powers and different bias currents are experimentally evaluated. The saturation effect has been found as the bias current increases. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26088
Higher order reconstruction for MRI in the presence of spatiotemporal field perturbations
Authors: Wilm Bertram J. , Barmet Christoph , Pavan Matteo , Pruessmann Klaas P. 
Published: April 2011

AbstractDespite continuous hardware advances, MRI is frequently subject to field perturbations that are of higher than first order in space and thus violate the traditional k‐space picture of spatial encoding. Sources of higher order perturbations include eddy currents, concomitant fields, thermal drifts, and imperfections of higher order shim systems. In conventional MRI with Fourier reconstruction, they give rise to geometric distortions, blurring, artifacts, and error in quantitative data. This work describes an alternative approach in which the entire field evolution, including higher order effects, is accounted for by viewing image reconstruction as a generic inverse problem. The relevant field evolutions are measured with a third‐order NMR field camera. Algebraic reconstruction is then formulated such as to jointly minimize artifacts and noise in the resulting image. It is solved by an iterative conjugate‐gradient algorithm that uses explicit matrix‐vector multiplication to accommodate arbitrary net encoding. The feasibility and benefits of this approach are demonstrated by examples of diffusion imaging. In a phantom study, it is shown that higher order reconstruction largely overcomes variable image distortions that diffusion gradients induce in EPI data. In vivo experiments then demonstrate that the resulting geometric consistency permits straightforward tensor analysis without coregistration. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Matching preclusion and conditional matching preclusion for bipartite interconnection networks II: Cayley graphs generated by transposition trees and hyper‐stars
Authors: Cheng Eddie , Hu Philip , Jia Roger , Lipták László 
Published: April 2011

AbstractThe matching preclusion number of a graph with an even number of vertices is the minimum number of edges whose deletion results in a graph that has no perfect matchings. For many interconnection networks, the optimal sets are precisely those induced by a single vertex. It is natural to look for obstruction sets beyond those induced by a single vertex. The conditional matching preclusion number of a graph is the minimum number of edges whose deletion results in a graph with no isolated vertices that has no perfect matchings. In this companion paper of Cheng et al. (Networks (NET 1554)), we find these numbers for a number of popular interconnection networks including hypercubes, star graphs, Cayley graphs generated by transposition trees and hyper‐stars. © 2011 Wiley Periodicals, Inc. NETWORKS, 2011
TiO2 nanotube supported metallocene catalysts for the preparation of nanofiber, nanosheet, and floccule of polyethylene
Authors: Hu Zhang , Liu Chengbin , Wu Yulin , Liu Ronghua , He Yejuan , Luo Shenglian 
Published: April 2011

AbstractEthylene polymerization was performed with the TiO2 nanotube supported metallocene catalytic system. The effects of Al/Zr molar ratio and time in polymerization on the catalytic behavior of the catalysts and the morphologies of the polyethylene were investigated. The nanofibers, floccules and nanosheets of polyethylene were obtained by controlling the polymerization conditions. Because the nanotubes confined the direction of propagation of the polyethylene chains, nanofibers were attained by extrusion polymerization, while the amount of floccules increased with extended polymerization time and nanosheets were mainly produced at high Al/Zr molar ratios. The possible correlation between the polymerization conditions and polyethylene morphologies was elucidated. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011.
Backside illuminated AlGaN‐on‐Si UV detectors integrated by high density flip‐chip bonding
Authors: Malinowski Pawel E. , Duboz Jean‐Yves , De Moor Piet , John Joachim , Minoglou Kyriaki , Srivastava Puneet , Abdul Hameed , Patel Manojkumar , Osman Haris , Semond Fabrice , Frayssinet Eric , Hochedez Jean‐Francois , Giordanengo Boris , Van Hoof Chris , Mertens Robert 
Published: April 2011

AbstractWe report on the fabrication of integrated AlGaN‐on‐Si‐based ultraviolet photodetectors. Devices were interconnected with dedicated Si‐based fanout structures using flip‐chip bonding. The interconnects were In solder bumps with a 20 µm pitch. Backside illumination was enabled by removing the Si substrate over the active area, leaving an ultrathin AlGaN membrane with the thickness of 400 nm and the area of 4x4 mm2 supported by an array of In bumps. The presented devices act as a test vehicle for the 10 µm pitch hybrid AlGaN Extreme Ultraviolet (EUV) imagers and prove the feasibility of backside illumination in an integrated device. The use of AlGaN as the active layer provides intrinsic solar blindness with a high rejection ratio of visible and infrared spectra, which is one of the most critical limitations of the commonly used Si‐based devices. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A bayesian strategy for screening cancer treatments prior to phase ii clinical evaluation
Authors: Thall Peter F. , Estey Elihu H. 
Published: April 2011

AbstractWe address the problem of selecting a treatment for phase II evaluation when several candidate treatments emerging from phase I testing are available. A pre‐phase II Bayesian selection design which randomizes patients among treatments is proposed. The patient group in the trial has prognosis more favourable than that of phase I patients but less favourable than the target group of the subsequent phase II trial. The patient response rate distribution in each treatment arm is continually updated during the trial for comparison with early termination cutoffs, and the best final treatment must satisfy a minimal posterior efficacy criterion. The primary aim is to replace the usual informal treatment selection process with a fair comparison formally based on a combination of prior opinion and clinical data.
A comparison of the power of two tests for qualitative interactions
Authors: Piantadosi S. , Gail M. H. 
Published: April 2011

Abstract‘Qualitative’ or ‘crossover’ interactions arise when a new treatment, compared with a control treatment, is beneficial in some subsets of patients and harmful in other subsets. We present a new range test for crossover interactions and compare it with the likelihood ratio test developed by Gail and Simon. The range test has greater power when the new treatment is harmful in only a few subsets, whereas the likelihood ratio test has greater power when the new treatment is harmful in several subsets. We provide power tables for both tests to facilitate sample size calculations for designing experiments to detect qualitative interactions and for interpreting the results of clinical trials.
Introduction to the recommendations from the National Institute on Aging‐Alzheimer's Association workgroups on diagnostic guidelines for Alzheimer's disease
Authors: Jack Clifford R. , Albert Marilyn S. , Knopman David S. , McKhann Guy M. , Sperling Reisa A. , Carrillo Maria C. , Thies Bill , Phelps Creighton H. 
Published: April 2011

BackgroundCriteria for the clinical diagnosis of Alzheimer's disease (AD) were established in 1984. A broad consensus now exists that these criteria should be revised to incorporate state‐of‐the‐art scientific knowledge.MethodsThe National Institute on Aging (NIA) and the Alzheimer's Association sponsored a series of advisory round table meetings in 2009 whose purpose was to establish a process for revising diagnostic and research criteria for AD. The recommendation from these advisory meetings was that three separate work groups should be formed with each assigned the task of formulating diagnostic criteria for one phase of the disease: the dementia phase; the symptomatic, pre‐dementia phase; and the asymptomatic, preclinical phase of AD.ResultsTwo notable differences from the AD criteria published in 1984 are incorporation of biomarkers of the underlying disease state and formalization of different stages of disease in the diagnostic criteria. There was a broad consensus within all three workgroups that much additional work is needed to validate the application of biomarkers for diagnostic purposes. In the revised NIA‐Alzheimer's Association criteria, a semantic and conceptual distinction is made between AD pathophysiological processes and clinically observable syndromes that result, whereas this distinction was blurred in the 1984 criteria.ConclusionsThe new criteria for AD are presented in three documents. The core clinical criteria of the recommendations regarding AD dementia and MCI due to AD are intended to guide diagnosis in the clinical setting. However, the recommendations of the preclinical AD workgroup are intended purely for research purposes.
Renal function in patients with urinary stones of varying compositions
Authors: Chou Yii‐Her , Li Ching‐Chia , Hsu Hsing , Chang Wei‐Chiao , Liu Chia‐Chu , Li Wei‐Ming , Ke Hung‐Lung , Lee Mei‐Hui , Liu Mu‐En , Pan Shu‐Ching , Wang Hsun‐Shuan 
Published: April 2011

AbstractKidney stones are a potential risk factor for chronic kidney disease. The impact of different urinary stone components on renal function is unknown. In this study, we retrospectively reviewed 1,918 medical records of patients with urolithiasis. The renal function was evaluated as estimated glomerular filtration rate. All the stones were analyzed by Fourier transform infrared spectroscopy. The patients were divided into five groups according to the stone components. Statistical analysis was performed with analysis of variance. All the patients with stones had Stage 2–3 chronic kidney disease. The patients with uric acid and struvite stones had significantly lower estimated glomerular filtration rate compared with those having other stone components (p < 0.01). Furthermore, the patients with calcium‐containing stones (calcium oxalate and calcium phosphate) had significantly better renal function than those with non‐calcium‐containing stones (struvite and uric acid, p < 0.01). Patients with urolithiasis had decreased renal function, and the impact of renal function varied depending on the stone components. We conclude that stone analysis is important in predicting the change in renal function in patients with urolithiasis. Moreover, the patients with non‐calcium‐containing stones, such as struvite and uric acid stones, should be carefully evaluated and treated to preserve their renal function.