bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uniaxial compression of SiO2 glass cylinders: analysis using stress‐independent material coefficients
Authors: Richter F. , Hoffmann H.‐J. 
Published: March 2011

AbstractGlass cylinders made of the vitreous silica type Suprasil 1 were exposed to axial stress at nominal compressive strain rates from –10–5 to –10–2 per second in a servohydraulic press at constant temperatures ranging from 1273 K to 1648 K. Subsequently, the stress was allowed to relax. True viscoelasticity is applied for evaluation of the experimental results and closed‐form solutions demonstrate that the interpretation as a single‐element Maxwell model renders Young's modulus readily measurable along with the tensile viscosity. The significant contribution of elasticity is found to be inherent in glass even at elevated temperatures. This very distinct property did not receive general recognition before and has been neglected in the majority of earlier studies on glass upsetting. The analysis reveals that the Young's modulus decreases with a rise in temperature if the nominal strain rate is held fixed, and with a reduction in nominal strain rate at constant temperature. The viscosity can be characterized as a function of the temperature either by a Vogel‐Fulcher‐Tammann‐Hess equation or by an Arrhenian fit. The findings when fed into a FEM programme reproduce the recorded force histories quite well. However, the present study reveals that the experimental data of Young's modulus depend on the stress. The results prove unambiguously the failure of linear viscoelasticity for this particular loading case. The full implications are reserved for a subsequent publication dealing with important consequences for glass rheology.
Corrosion properties of thermal sprayed aluminium (TSA) coatings deposited by powder flame spraying
Authors: Glogović Z. , Alar V. , Kožuh Z. , Stojanović I. , Kralj S. 
Published: March 2011

AbstractThermal sprayed aluminium (TSA) coatings are widely used for the protection of steels from aqueous corrosion, including offshore structures and components that are exposed to seawater immersion, tidal and splash zone environments. In this paper, the influence of deposition parameters of aluminium coating on its corrosion properties was studied. For different application parameters of TSA coatings, the thickness, the microstructure and corrosion properties were determined. Determination of thickness was performed according to EN ISO 2064:2000 relating to the definition and determination of the thickness of metallic and other inorganic layers. Microstructure was determined using a Olympus GX50 optical microscope. The corrosion properties of the coatings were compared using an accelerated electrochemical corrosion test method. Electrochemical studies were carried out in accordance with the requirements of ASTM standard G 102 – 89. The TSA coating performance was quantified in terms of its corrosion potential and the corrosion rate, which was estimated from Tafel polarisation resistance measurements.
Load dependence of the apparent Knoop hardness of SiC ceramics in a wide range of loads
Authors: Majić M. , Ćurković L. , Ćorić D. 
Published: March 2011

AbstractSilicon carbide (SiC) ceramics is a material with increasing use, due to its excellent mechanical properties, especially high hardness. In order to integrate this material into design process, we need to know its hardness as precise as possible. The Knoop hardness number (HK) is calculated using the expression: HK = α·F/d2, where F is the applied load, d is the long diagonal of the resulting 10indentation and a is the Knoop indenter geometrical constant. In this paper, the Knoop hardness of SiC ceramics was measured in the applied load range from 4.9 to 98.07 N. For some materials measured “apparent” hardness value decreases with increasing applied test load (normal indentation size effect – ISE), while for some materials measured “apparent” hardness increases with increasing applied test load (reverse indentation size effect – RISE). Obtained results show the measured hardness exhibits the ISE. In the literature several models are given for the phenomenon explanation. We used the following models: Meyer's law (F = K·dn), proportional specimen resistance – PSR (F = a1·d + a2·d2) and modified proportional specimen resistance – MPSR model (F = a0 + a1·d + a2·d2). Results of regression analysis for all applied models show they can all be used for ISE analysis. “True” hardness was determined based on the PSR and MPSR model (HKT = α·a2). The obtained results were similar. If the specimen surface is carefully prepared and the range of loads is wide, the a0 coefficient from MPSR model reaches small values and can be excluded. Therefore, for the calculation of SiC ceramics Knoop hardness, the simpler model (PSR) can be used.
Gait in SWEDDs patients: Comparison with Parkinson's disease patients and healthy controls
Authors: Mian Omar S. , Schneider Susanne A. , Schwingenschuh Petra , Bhatia Kailash P. , Day Brian L. 
Published: March 2011

AbstractPatients diagnosed with Parkinson's disease on clinical grounds who subsequently turn out to have normal dopamine transporter imaging have been referred to as SWEDDs (scans without evidence of dopaminergic deficits). Despite having clinical features similar to those of Parkinson's disease, these patients seem to have different pathophysiology, prognosis, and treatment requirements. In this study we determined the similarities and differences in the gaits of SWEDDs and Parkinson's disease patients to investigate whether walking patterns can distinguish these entities. We used 3‐D motion capture to analyze the gaits of 11 SWEDDs patients (who had unilateral or asymmetric upper limb tremor with a rest component), 12 tremor‐dominant Parkinson's disease patients, and 13 healthy control participants. In common with Parkinson's disease patients, SWEDDs patients had a slow gait mainly because of a small stride length, as well as a reduced arm swing. However, several abnormal features of posture and gait in Parkinson's disease were normal in SWEDDs. Thus, SWEDDs patients had normal trunk and elbow posture, normal stride length variability, and normal bilateral step‐phase coordination, all of which were abnormal in Parkinson's disease patients. We also searched for signs of ataxic movements during normal and tandem walking, but found no evidence that ataxic gait was a general feature in SWEDDs. These findings could aid the clinician in identification of potential tremulous SWEDDs cases. © 2011 Movement Disorder Society
Coffees rich in chlorogenic acid or N‐methylpyridinium induce chemopreventive phase II‐enzymes via the Nrf2/ARE pathway in vitro and in vivo
Authors: Boettler Ute , Volz Nadine , Pahlke Gudrun , Teller Nicole , Kotyczka Christine , Somoza Veronika , Stiebitz Herbert , Bytof Gerhard , Lantz Ingo , Lang Roman , Hofmann Thomas , Marko Doris 
Published: March 2011

AbstractRecently, the coffee constituents 5‐O‐caffeoylquinic acid (CGA) and N‐methylpyridinium (NMP) were identified as inducers of the Nrf2/antioxidant‐response element (ARE) detoxifying pathway under cell‐culture condition. To study the impact of CGA and NMP on the Nrf2‐activating properties of a complex coffee beverage, two different model coffees were generated by variation of the roasting conditions: a low‐roast coffee rich in CGA and a heavy‐roast low in CGA but containing high levels of NMP. Activation of the Nrf2/antioxidant‐response element pathway was monitored in vitro and in vivo.
Design of micro‐sized differential antenna for 2.4‐GHz mobile payment applications
Authors: Shen Jianghua , Lv Bo , Shen Fazhong , Huangfu Jiangtao , Ran Lixin 
Published: March 2011

AbstractIn this article, we propose a design and on‐board measuring approach for the realization of micro‐sized differential antennas for the 2.4‐GHz mobile payment (MP) applications. Exampled by a complete realization of a 3 × 11 mm2‐sized differential antenna driven by a commercial 2.4‐GHz transceiver integrated inside a 15 × 11 mm2‐sized micro‐SD card, such design and testing approach is described in detail. The experimental measurements of the micro‐sized antenna show that the impedance of the designed micro‐sized differential antenna well matches the complex impedance of the transceiver, and, therefore, ensure the stability of the radio frequency performance required by the MP applications. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1419–1422, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25957
Accuracy–efficiency tradeoff of temporal basis functions for time‐marching solvers
Authors: Kaur Guneet , Yilmaz Ali E. 
Published: March 2011

AbstractAn investigation of the impact of the temporal discretization on the marching‐on‐in‐time solution of integral equations is presented. Numerical results that quantify the efficiency–accuracy tradeoff for causal piecewise polynomial and band‐limited interpolatory functions are presented. It is observed that the former is more efficient for low to moderate accuracy levels, and the latter achieves higher, but extrapolation‐limited, accuracy levels. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1343–1348, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25960
Tunable near‐field subwavelength microwave imaging
Authors: Pochiraju Tejprakash , Malyuskin Oleksandr , Fusco Vincent 
Published: March 2011

AbstractIn this article, we show that a dielectric filled slot into which a capacitively loaded printed dipole antenna is inserted is capable of producing squeezing of the near electric field when excited by a cross polarized signal. Further, it is demonstrated that this effect can be used to produce a simple sensor which is capable of producing tunable subwavelength imaging of scattering objects. Results are presented which show that with commercial surface mount components subresolution of better than 0.25λ is possible across a 500 MHz bandwidth from 2.53 to 3.08 GHz with varactor tuning. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1229–1231, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25966
Design of multiwavelength DFB fiber laser with equivalent phase shifts
Authors: Jia Linghui , Yin Zuowei , Zhang Liang , Chen Xiangfei 
Published: March 2011

AbstractA dual‐wavelength distributed feedback fiber laser with two equivalent phase shifts is proposed and demonstrated experimentally. By studying varied parameters of the fiber laser, which show different impacts on the lasers' characteristic, a dual‐wavelength laser of 31 pm spacing is designed and fabricated. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1453–1456, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25969
Frequency‐tunable 150W harmonic‐tuned power oscillator
Authors: Shin Suk‐Woo , Choi Jin‐Joo 
Published: March 2011

AbstractIn this article, a frequency‐tunable 150W harmonic‐tuned power oscillator is presented. The harmonic‐tuned power amplifier of the oscillator was designed for improving drain efficiency with a single laterally diffused metal oxide semiconductor transistor using a nonlinear harmonic balance simulation code. The oscillation frequency was tuned by a mechanical phase shifter in the delay‐line feedback loop circuit. Experimental results show that the output power and the drain efficiency of the oscillator were almost same as in the power amplifier with the same transistor and operating in the same frequency range. The measured output power and drain efficiency of the fabricated oscillator were 51.8 ± 0.6 dBm and better than 55.9%, respectively, across the 902–928 MHz band. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1459–1462, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25970
Wideband antenna with shaped beams for wireless communication indoor applications
Authors: Guo Jing‐li , Zhou Shi‐gang , Zou Yan‐lin , Liu Qi‐zhong 
Published: March 2011

AbstractA wideband antenna for DCS‐1800, PCS‐1900, WCDMA/IMT‐2000, WLAN, and TD‐SCDMA indoor applications is presented. The antenna consists of two half circle shaped radiating patches, a feeding ground and a reflector ground. The coupling between two patches is considered in the design of the antenna. The two patches are fed with 90° phase difference, which leads to down‐tilted radiation patterns when the antenna is mounted on a wall. A prototype is constructed and tested. Simulated and measured results are given. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1377–1379, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25973
Performance of microstrip patch antenna on a reinforced carbon fiber composite ground plane
Authors: Mehdipour Aidin , Sebak Abdel‐Razik , Trueman Christopher W. , Rosca Iosif D. , Hoa Suong V. 
Published: March 2011

AbstractThe performance of a microstrip patch antenna operating against a carbon fiber composite ground plane is investigated and compared with results for a copper ground, both numerically and experimentally.An electromagnetic model (EM) of the composite antenna is developed using Microwave Studio for numerical analysis. The ground plane is made of continuous reinforced carbon fiber composite composite, which has anisotropic conductivity. The direction of the fibers in the ground plane affects the current distribution, and hence the impedance bandwidth and the matching characteristics of the antenna. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1328–1331, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25976
Wideband monopole antenna coupled with a chip‐inductor‐loaded shorted strip for LTE/WWAN mobile handset
Authors: Chen Shu‐Chuan , Wong Kin‐Lu 
Published: March 2011

AbstractAn eight‐band long term evolution/wireless wide area network (LTE/WWAN) mobile handset antenna using a wideband monopole antenna coupled with a chip‐inductor‐loaded shorted strip is presented. Two wide operating bands are obtained to cover the eight‐band LTE/WWAN operation in the 698–960 and 1710–2690 MHz bands. The antenna's lower band is contributed by the coupled shorted strip of length about 100 mm which is short‐circuited to the system ground plane of the mobile handset through a loaded chip inductor of 10 nH. The loaded chip inductor leads to dual‐resonant behavior of the excited resonant mode and greatly enhances the lower‐band bandwidth. The upper band is formed by a wide resonant mode generated by the wideband monopole antenna and a higher‐order resonant mode generated by the coupled shorted strip. The upper‐band bandwidth of larger than 1 GHz is hence obtained. With two wide bands obtained, the antenna can be disposed on the bottom edge of the main circuit board of the mobile handset with a small board area of 10 × 60 mm2. The specific absorption rate (SAR) values of the antenna for 1‐g head tissue are also well below the limit of 1.6 W/kg for frequencies over the operating bands. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1293–1298, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25977
A dual‐band Gysel power divider with the even‐mode input extension/stub lines
Authors: Park Myun‐Joo , Lee Byungje 
Published: March 2011

AbstractA new dual‐band structure is proposed for the Gysel power divider. The proposed divider features an extension line at the input and a stub line at the opposite end, both located along the symmetry plane and operating at the even‐mode excitation of the divider. The divider is analyzed rigorously to derive the exact design equations in closed‐form formula. The design, simulation and experiments based on the proposed method confirm the dual‐band capability of the divider. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1213–1216, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25979
A high CMRR BiCMOS active combiner balun
Authors: Gautier Jean‐Luc , Temcamani Farid , Régis Myrianne , Diab Hilda 
Published: March 2011

AbstractAn integrated bipolar differential amplifier was optimized to have maximum common mode rejection ratio (CMRR).This amplifier was then used as combiner and splitter baluns. A prototype was fabricated using a SiGe bipolar technology. Measurements show high CMRR and good agreement with simulations. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1253–1256, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25981
Detection by using dielectric materials and generation of millimeter wave in optical‐to‐radio frequency systems connecting wavelength division multiplexing and wireless networks
Authors: Park Ki‐Hwan 
Published: March 2011

AbstractA 50–60 GHz continuous wave (cw) millimeter wave (MMW) converted from optical signals was detected by using dielectric materials of various kinds for optical‐to‐radio frequency systems.The converted MMW signals were radiated inside a millimeter waveguide through dielectric materials covering either the top of an optical waveguide or the bottom of an LN substrate and detected by a detector. The detected spectral linewidth of the MMW signals was less than 1 kHz. The power of the MMW signals obtained through the only Teflon or alumina at a 50–60 GHz range was larger than that detected by the strip‐waveguide beyond 5 dBm. When copper plate was inserted between the Teflon and LN substrate, the measured MMW power was larger than that detected by a strip‐waveguide beyond 15 dBm. The power of the MMW signals obtained from the bottom of an LN substrate was larger than that detected at the top of an optical waveguide beyond 5 dBm in the same range. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1409–1413, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25986
Analysis and design of a wide band omnidirectional antenna
Authors: Jacobs Ockert B. , Odendaal J. W. , Joubert Johan 
Published: March 2011

AbstractThe analysis and design of an omnidirectional antenna that functions over a very broad frequency band is presented. Design guidelines for this antenna have been derived using electromagnetic analysis software. Measured results of a prototype developed according to these guidelines are presented. These results are compared to simulation results to illustrate the validity of the model used to derive the empirical design guidelines. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1352–1356, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25990
Miniaturized substrate integrated waveguide filter with complementary spiral resonator
Authors: Zhou Liang , Liu Shaobin , Gao Nan , Chen Yu , Wei Yinsheng 
Published: March 2011

AbstractIn this letter, the miniaturized substrate integrated waveguide (SIW) filter is proposed using a complementary spiral resonator (CSR). The CSR is based on the multiple turns SR (SRm), which was introduced in 2004 by some of the authors. CSR technique can be applied to the design of miniaturized filter by increasing electrical length. To demonstrate the idea, the miniaturized SIW filter is designed with CSR2 and CSR3, respectively. The measured central resonant frequencies are 3.25 and 2.23 GHz, which are lower than the SIW filter with complementary split‐ring resonator occurs at 5.17 GHz. Details of the experimental results compared with the simulated results are presented and discussed. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1308–1311, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25992
Design of quad‐band bandpass filter using assembled resonators
Authors: Chen Fu‐Chang , Chu Qing‐Xin 
Published: March 2011

AbstractThis letter presents a novel approach for designing quad‐band bandpass filter with independently controlled center frequencies.Assembled resonator constructed by a stepped impedance resonator (SIR) and a stub‐loaded SIR is employed to obtain quad‐band responses. The SIR is designed to operate at the second and fourth passbands and the stub‐loaded SIR is designed to operate at the first and third passbands. Good agreement is shown between the simulation and the measurement, the resonators are meandered to give an overall circuit size of about 21.8 × 30.2 mm2. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1305–1308, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25993
Compact quad band monopole antenna
Authors: Lin Chih‐Peng , Chang Chieh‐Hsiang , Jou Christina F. 
Published: March 2011

AbstractIn this article, a compact quad band monopole antenna is demonstrated. Asymmetric coplanar strip feeding is applied in the design in order to compact the size. The proposed antenna fabricated on a FR4 substrate has an overall size of 30–30 mm2. By integrating an invert‐C slot and a modified invert‐F strip into an invert‐C patch, multiple resonant frequencies can be excited at 1.1, 2.35, 3.6, and 5.4 GHz individually for global positioning system, wireless local area network, Bluetooth/ISM, and Wi‐MAX applications. The measured result has shown a good agreement with the simulation results. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1272–1276, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25994
Compact planar hexa‐band inverted‐F antenna for mobile phone application
Authors: Ma J. , Yin Y.‐Z. , Hu W. , Ren X.‐S. 
Published: March 2011

AbstractThis article presents a compact multiband planar inverted‐F antenna design for mobile phone applications. The proposed antenna comprises dual twisted lines, a shorting strip and an L‐shaped coupling strip. The dual twisted lines are excited by the coupling strip to generate four resonance modes around 900, 1800, 2100, and 3500 MHz and covers six bands including the global system for mobile communication 850/900 (824–894 MHz), (880–960 MHz), digital communication system (1710–1880 MHz), personal communication system (1850–1990 MHz) universal mobile telecommunication system (1920–2170 MHz) and worldwide interoperability for microwave access (3400–3600 MHz). The antenna shows a planar structure and occupies a very small‐size of 15 × 26 mm2, making it especially suit for mobile phone applications. This research performed simulation by high frequency structure simulation and CST to design and analyze the antenna, and a practical structure was fabricated and tested. The measured and simulated return loss show good agreement. Moreover, the radiation patterns and the specific absorption rate are discussed too. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1233–1236, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25996
All‐optical clocked D flip‐flop memory using a hybrid integrated S‐R latch
Authors: Reis C. , Maziotis A. , Kouloumentas C. , Stamatiadis C. , Bougioukos M. , Calabretta N. , André P. , Dionisio R. , Neto B. , Dorren H. J. S. , Avramopoulos H. , Teixeira A. 
Published: March 2011

AbstractWe demonstrate, by using multiple Mach‐Zehnder interferometer (MZI)‐semiconductor optical amplifier structures, an all‐optical synchronous D type flip‐flop, with high‐photonic integration capability. Experimental performance analysis shows its functional and performance feasibility and high‐switching speeds were achieved. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1201–1204, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25998