bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bandwidth enhancement of coupled‐fed on‐board printed PIFA using bypass radiating strip for eight‐band LTE/WWAN slim mobile phone
Authors: Chen Shu‐Chuan , Wong Kin‐Lu 
Published: June 2010

AbstractBy connecting a bypass radiating strip to the radiating portion of a coupled‐fed on‐board printed PIFA (planar inverted‐F antenna), significant bandwidth enhancement can be obtained.The bypass radiating strip provides a bypass for the excited surface currents of the printed PIFA, which leads to more uniform surface current distributions on the printed PIFA. This behavior can result in slow variations in the antenna's input impedance over the operating bands, which makes it very promising to achieve improved impedance matching; thus, enhanced bandwidths of the printed PIFA are obtained. In this study, with a small footprint to be printed on the no‐ground portion of 15 × 48 mm2 in the system circuit board of the mobile phone, the proposed on‐board printed antenna is especially suitable for slim mobile phone applications and can generate two wide operating bands to respectively cover the LTE700/GSM850/900 operation (698–960 MHz) and the GSM1800/1900/UMTS/LTE2300/2500 operation (1710–2690 MHz). The proposed antenna held by the user's hand and attached to the user's head is also tested for its SAR values over the eight operating bands. Measured and simulated results are presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2059–2065, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25406
Design of V‐band CMOS down‐converting cascode mixer
Authors: Kuo Hsin‐Chih , Chuang Huey‐Ru , Huang Tzuen‐Hsi 
Published: June 2010

AbstractThis article presents a V‐band down‐converting cascode mixer fabricated in the 0.13‐μm CMOS process.The mixer utilizes the cascode topology and adds a buffer to avoid loading effects. The V‐band mixer exhibits a conversion gain of −1.7 dB, an input 1‐dB compression point of −8 dBm at RF of 60 GHz, IF of 5 GHz, and LO power of 0 dBm. The RF‐IF isolation is more than 26 dB. The LO‐RF isolation is more than 15 dB. In addition to the good agreement between simulation and measurement, the proposed cascode CMOS mixer with a small chip size has a complete measured performance for further 60‐GHz receiver RF front‐end integration. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1973–1977, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25408
Internal WWAN antenna for the clamshell mobile phone with various chassis shapes
Authors: Wong Kin‐Lu , Lee Cheng‐Tse , Lyu Chao‐An 
Published: June 2010

AbstractStable performances of an internal WWAN antenna applied in the clamshell mobile phone with various chassis shapes are obtained. Six different states including five possible operating states and one closed state (idle condition) of the clamshell mobile phone, wherein the chassis shapes (main ground and upper ground) vary greatly, are studied. The WWAN antenna is mounted at the bottom of the main ground, and there are three connecting positions between the main ground and the upper ground. For each operating states, the upper ground is connected to the main ground at one of the three connecting positions. At each position, a band‐stop circuit formed by two parallel LC chip elements is embedded, which is designed to excite a parallel resonance at around 900 MHz and hence leads to very high impedance seen into the upper ground in the 900 MHz band. This greatly decreases the excited surface currents on the upper ground, making the presence of the upper ground to have very small effects on the performances of the WWAN antenna mounted at the bottom of the main ground. At around 1900 MHz, owing to its shorter wavelength, the surface currents on the upper ground excited by the WWAN antenna on the main ground are small. Thus, over both the 900‐ and 1900‐MHz bands, the various orientations of the upper ground to the main ground cause small effects on the WWAN antenna embedded therein. Details of the obtained results are presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2148–2154, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25413
An elliptically flared waveguide horn
Authors: Malherbe J. A. G. , Katcodia Y. 
Published: June 2010

AbstractAn X‐band waveguide horn of which the sides flare by an elliptic function is described. Measurements performed show that the structure exhibits an absence of side lobes in the conventional sense, and that the radiation pattern varies very little over the entire X‐band. It has almost equal beamwidth in the principal planes, and the input return loss is extremely low. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2118–2120, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25414
Fabrication of system with probe for high‐frequency measurement applications
Authors: Matsumoto Keiji , Choi Woon , Tomokage Hajime 
Published: June 2010

AbstractIn this study, a new type of low temperature co‐fired ceramic (LTCC) probes fabricated using the system‐in‐package (SiP) technology is proposed; these probes are used for high‐frequency measurements. The advantage of LTCC probes is that suitable structures of the metal tips of their electrodes can be easily created by cutting LTCC sheets during the fabrication process. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2083–2087, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25416
Slits‐loaded microstrip antennas for circular polarization
Authors: Nasimuddin N. , Qing X. , Chen Z.N. 
Published: June 2010

AbstractNovel diagonally slits‐loaded compact microstrip antennas are proposed for circular polarization (CP). A group of four slits is loaded on the square patch radiator for compact antenna size with CP radiation. The slit with unequal sizes loaded on square patch in diagonal directions is used to achieve CP radiation. The combined V‐shaped and square slits, diagonally loaded, microstrip antenna is compact when compared with V‐shaped slits loaded microstrip antenna. The measured 10‐dB return loss and 3‐dB axial‐ratio bandwidths are 3.55% and 0.82%, respectively, for a combined V‐shaped and square slits loaded microstrip patch antenna. The overall size of the antenna is 0.256λ0×0.256λ0×0.0136λ0 at 2.55 GHz. The proposed slits‐loaded patch radiator is useful for compact circularly polarized microstrip antenna and array designs. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2043–2049, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25417
Fast directional multilevel algorithm combined with Calderon multiplicative preconditioner for stable electromagnetic scattering analysis
Authors: Chen H. , Zhu J. , Chen R. S. , Fan Z.H. 
Published: June 2010

AbstractIn this article, a new method called fast directional multilevel algorithm (FDMA) is proposed for three‐dimensional electromagnetic problems. Combined with the Caldron identities of Calderon multiplicative preconditioner (CMP), the new algorithm has a fast convergence rate of iterative solvers and is stable at low frequency for the electrical field integral equation solutions. Like the fast multipole method, octree structure is used in our proposed algorithm. However, the new algorithm does not require the implementation of multipole expansions of the Green's function but based only on kernel evaluations. It does not suffer from low‐frequency breakdown when the discretization density is high. The numerical results demonstrate that the CMP‐preconditioned FDMA leads to significant reduction of both the iteration number and the computer processing use (CPU) time for radar cross section (RCS) calculation. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1963–1969, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25421
Miniaturization of an UHF RFID reader antenna using an artificial magneto‐dielectric
Authors: Chung Haeil , Lee Youngki , Choi Jaehoon 
Published: June 2010

AbstractIn this article, a miniaturization method for a ultrahigh frequency radio frequency identification reader antenna using an artificial magneto‐dielectric is proposed. The miniaturization was achieved using an artificial magneto‐dielectric, realized using a split ring resonator (SRR). The 10 dB return loss bandwidth of the designed antenna ranges from 908.5 to 914 MHz. The measured peak gain is −3.75 dBi and the axial ratio is below 3 dB over the frequency band of interest. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1926–1930, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25423
Preparation of amino acid ester substituted polyphosphazene microparticles via electrohydrodynamic atomization
Authors: Xue Liwei , Mao Lixin , Cai Qing , Yang Xiaoping , Jin Riguang 
Published: June 2010

AbstractThis study aims to fabricate biodegradable polyphosphazene microparticles by electrohydrodynamic atomization (EHDA) for applications in drug delivery system. Polyphosphazene microparticles with varied morphologies, such as spherical, doughnut‐shaped, and corrugated, were resulted from electrospraying depending on solvents, molecular weight of polyphosphazene, and concentration of polymeric solution. The solubility of polyphosphazene in different solvents was found to be a significant factor determining the particle‐to‐fiber formation, while concentration of polymeric solution has remarkable effect on particle morphology. Accordingly, a graphic description was proposed to interpret the formation of polyphosphazene microparticles during EHDA. Copyright © 2010 John Wiley & Sons, Ltd.
Structure and wettability relationship of coelectrospun poly (L‐lactic acid)/gelatin composite fibrous mats
Authors: Yang Xiaoping , Xu Qingqing , Yan Na , Sui Gang , Cai Qing , Deng Xuliang 
Published: June 2010

AbstractCoelectrospun polylactide(PLA)/gelatin (GE) composite fibrous matrixes have been identified to exhibit much improved performances compared to the respective components; however, the reasons for their water contact angles decreasing to zero at proper PLA/GE ratios remain unclear. To get a deep understanding of the phenomenon, PLA and GE were coelectrospun with different PLA/GE ratios in this study. Although the resulting composite fibers were homogeneous in appearance, they were detected different microscopic structures by transmission electron mircroscope (TEM) and via morphological observations after selective removal of either PLA or GE component. Together with the results of degradation study in phosphate buffered solution, a kind of cocontinuous phase separation microstructure could be identified for the PLA(50 wt%)/GE(50 wt%) composite fibers, which also showed the water contact angle of 0°. This value was far lower than those of electrospun PLA (∼123°) and GE (∼42°) fibrous matrixes. The X‐ray photoelectron spectrometry (XPS) data revealed that the polar side groups of protein macromolecules have moved toward composite fiber surface with solvent evaporation during electrospinning, due to the hydrophobic interaction between PLA and GE. Then the excellent hydrophilicity of PLA(50 wt%)/GE(50 wt%) composite fibers could be suggested as the consequence of: (1) the cocontinuous phase separation structure could provide more interface and void for water molecules penetrating; and (2) the accumulation of polar groups on composite fiber surface significantly increased the surface wettability. Copyright © 2010 John Wiley & Sons, Ltd.
Fabrication of conducting polyaniline–multiwalled carbon nanotube nanocomposites and their use as templates for loading gold nanoparticles
Authors: Kumar Nanjundan Ashok , Jeong Yeon Tae 
Published: June 2010

AbstractA new and effective route to synthesize conducting polyaniline‐multiwalled carbon nanotube (PANI ‐f‐MWNT) nanocomposites (where ‘f’ denotes that the MWNTs have been functionalized) starting with amine‐protected 4‐aminophenol is reported. Aminophenol‐functionalized MWNTs were initially synthesized by functionalizing acyl chloride‐terminated nanotubes with N‐(tert‐butoxycarbonyl)‐4‐aminophenol followed by the in situ chemical oxidative grafting of aniline in the presence of ammonium persulfate as an oxidizing agent. Control of the morphology and thickness of the polymer–MWNT nanocomposites was achieved by varying the weight ratios of aniline monomers and MWNTs in the polymerization process. Fourier transform infrared spectroscopy was employed to characterize the initial changes in surface functionalities which also confirmed that PANI was covalently grafted to the MWNTs. Electron microscopy and UV‐visible absorption spectroscopy were employed to characterize the morphology and chemical structure of the resulting hybrids. The results obtained indicate that the structure of the MWNTs was not perturbed by the incorporation of PANI. The content of the polymer in the nanocomposites was determined thermogravimetrically, while the electrical conductivity was obtained using four‐probe measurements. The PANI ‐f‐MWNT nanocomposites were adopted as templates for further decoration with gold nanoparticles in solution, thus opening new possibilities for their prospective technological applications. Copyright © 2010 Society of Chemical Industry
Liver‐targeting doxorubicin‐conjugated polymeric prodrug with pH‐triggered drug release profile
Authors: Huang Jin , Gao Feng , Tang Xiaoxin , Yu Jiahui , Wang Daxin , Liu Shiyuan , Li Yaping 
Published: June 2010

AbstractThe aim of the research presented was to develop a potential liver‐targeting prolonged‐circulation polymeric prodrug of doxorubicin (Dox) with a pH‐triggered drug release profile. In particular, linear dendritic block copolymers composed of polyamidoamine dendrimer (PAMAM) and poly(ethylene glycol) (PEG; number‐average molecular weight of 2000 g mol−1) with or without galactose (Gal) were synthesized. Dox was coupled to the copolymers via an acid‐labile hydrazone linker. These prodrugs, designated Gal‐PEG‐b‐PAMAM‐Doxn and mPEG‐b‐PAMAM‐Doxm, showed accelerated Dox release as the pH decreased from 8.0 to 5.6. Cytotoxicity of the prodrugs was lower than that of free Dox due to the gradual drug release nature. Compared to mPEG‐b‐PAMAM‐Doxm, Gal‐PEG‐b‐PAMAM‐Doxn showed rather high cytotoxicity against Bel‐7402, suggestive of its galactose receptor‐mediated enhanced tumor uptake. This galactose receptor‐mediated liver‐targeted profile was further confirmed by the prolonged retention time in hepatoma tissue monitored using magnetic resonance imaging. Gal‐PEG‐b‐PAMAM‐Doxn showed better in vivo antitumor efficacy than free Dox, suggesting its great potential as a polymeric antitumor prodrug. Copyright © 2010 Society of Chemical Industry
The effect of chain packing on the thermal and dynamic mechanical behaviour of liquid‐crystalline epoxy thermosets
Authors: Giamberini Marta , Malucelli Giulio , Ambrogi Veronica , Capitani Donatella , Cerruti Pierfrancesco 
Published: June 2010

AbstractLiquid‐crystalline thermosets (LCTs) have received considerable attention since they exhibit many interesting properties. However, some aspects concerning LCTs are still unexplored. In particular, the structure–property relationships, as far as the organization of liquid‐crystalline (LC) domains in cured thermosets is concerned, have not been fully elucidated yet. We investigated the effect of the presence of a nematic mesophase on the thermal and dynamic mechanical behaviour of p‐(2,3‐epoxypropoxy)phenyl‐p‐(2,3‐epoxypropoxy)benzoate cured with 2,4‐diaminotoluene. Fourier transform infrared spectral analysis showed that epoxy group conversion was complete in both LC and isotropic (ISO) systems; moreover, a greater amount of intermolecular hydrogen bonding in the LC material was found. Thermogravimetric analysis evidenced similar thermal stability for the two systems, but a kinetic analysis of the data showed that the degradation process is more complex for the LC sample, and is characterized by higher activation energy. Dynamic mechanical thermal analysis (DMTA) showed lower glass transition temperature values for the LC system. Solid‐state NMR analysis evidenced lower paramagnetic oxygen absorption for this system. DMTA results show that the ISO material possesses a larger number of physical crosslinks, which act as extra constraints on the molecular motions. In the case of the LCT, the formation of a locally more dense structure is postulated, where the presence of more extended macromolecular segments leads to a smaller number of physical crosslinks, as also confirmed by solid‐state NMR analysis. A more compact molecular packing also leads to an increase of the activation energies of the thermal degradation process of the LC system. Copyright © 2010 Society of Chemical Industry
CH3CH2SCH3 + OH radicals: temperature‐dependent rate coefficient and product identification under atmospheric pressure of air
Authors: Oksdath‐Mansilla Gabriela , Peñéñory Alicia B. , Albu Mihaela , Barnes Ian , Wiesen Peter , Teruel Mariano A. 
Published: June 2010

AbstractRelative rate coefficients have been determined for the gas‐phase reaction of hydroxyl (OH) radicals with ethyl methyl sulfide (EMS) using isobutene as a reference compound. The experiments were performed in a 1080 L quartz glass photoreactor in the temperature range of 286–313 K at a total pressure of 760 ± 10 Torr synthetic air using in situ FTIR absorption spectroscopy to monitor the concentration‐time behaviors of reactants and products. OH radicals were produced by the 254 nm photolysis of hydrogen peroxide (H2O2).The kinetic data obtained were used to derive the following Arrhenius expression valid in the temperature range of 286–313 K (in units of cm3 molecule−1 s−1): $k = (3.0 \pm 0.6) \times 10^{ - 15} \exp \left[ {{{(2457 \pm 65)} \mathord{\left/ {\vphantom {{(2457 \pm 65)} T}} \right. \kern-\nulldelimiterspace} T}} \right]$The rate coefficient displays a negative temperature dependence and low pre‐exponential factor which supports the existence of an addition mechanism for the reaction involving reversible OH‐adduct formation. The results are compared with previous data of other sulfides from the literature and are rationalized in terms of structure–reactivity relationships.Additionally, product identification of the title reaction was performed for the first time by the FTIR technique under atmospheric conditions. Sulfur dioxide, formaldehyde, and formic acid were observed as degradation products in agreement with the two possible reaction channels (addition/abstraction). Copyright © 2010 John Wiley & Sons, Ltd.
Methyl cation affinity (MCA) values for phosphanes
Authors: Lindner Christoph , Maryasin Boris , Richter Frank , Zipse Hendrik 
Published: June 2010

AbstractMethyl cation affinity (MCA) values have been calculated for a variety of phosphanes at the MP2(FC)/6‐31+G(2d,p)//B98/6‐31G(d) level of theory. The analysis of MCA values for tri‐alkyl phosphanes reveals that substituent effects are additive for unbranched and cyclic alkyl substituents, and (with some modification) also for most of the branched alkyl substituents. Copyright © 2010 John Wiley & Sons, Ltd.
Spectrally dependent locations of hot‐spots in nanoparticle clusters
Authors: Letnes Paul Anton , Simonsen Ingve 
Published: June 2010

AbstractWe study the optical response of clusters of metallic nanospheres in the electrostatic approximation, using a spherical harmonic representation of the electric field. Field enhancement and near field interactions between the spheres are investigated numerically. Symmetry properties of certain clusters give rise to highly localized maxima of the electric field, denoted “hot spots.” From numerical experiments performed at optical frequencies of the incident light, it is found that various geometrical configurations exhibit interesting phenomena; in particular, that hot spots move spatially around as a function of the frequency of the incident light. We present simulation results for the simplest nanoparticle cluster known to exhibit these interesting phenomena, namely, a regular octahedron.
Bond models in linear and nonlinear optics
Authors: Aspnes D. E. 
Published: June 2010

AbstractAtomic‐scale descriptions of linear‐optical properties such as reflection are nearly a century old, but surprisingly, analogous models describing nonlinear‐optical (NLO) properties as the natural dynamic response of bond charges driven by an external field are a recent development. These bond‐charge models have proven to be particularly useful in describing the relevant physics of second‐, third‐, and fourth‐harmonic generation, identifying previously unrecognized contributions to NLO responses, and uncovering well‐disguised correlations in tensor parameters determined phenomenologically from symmetry conditions. Current capabilities are discussed, and opportunities for improved understanding noted.
Optical properties of GaSb(001)‐c(2 × 6): The role of surface antisite defects
Authors: Hogan Conor , Magri Rita , Del Sole Rodolfo 
Published: June 2010

AbstractWe consider the formation of surface antisite defects on a previously proposed model for the GaSb(001)‐c(2 × 6) surface. Based on ab initio total energy calculations, we show how these defects stabilize the otherwise metallic surface and how their formation is driven by the excess charge associated with the Sb‐rich surface conditions. The surface‐sensitive optical technique of reflectance anisotropy spectroscopy is shown to be crucial for detecting the defects, and computation of spectra yields a good agreement with experiment when defects are included in the surface reconstruction.
Electronic structure and Compton profiles of CdO and HgO
Authors: Choudhary Gopal , Raykar Veera , Tiwari Shailja , Dashora Alpa , Ahuja Babu Lal 
Published: June 2010

AbstractWe present the first ever measured experimental electron momentum densities of CdO and HgO at an intermediate resolution using 20 Ci 137Cs Compton spectrometer. The measurements are compared with the theoretical Compton profiles using density functional theory (DFT) and hybridization of DFT with the Hartree–Fock as embodied in linear combination of atomic orbitals (LCAO) scheme. In addition, we have also calculated the energy bands and density of states using the full potential linearized augmented plane wave method and the LCAO schemes. It is seen that the hybridization scheme, which overestimates the band gap, gives a better agreement with the experimental profiles. A comparative nature of bonding is also discussed in terms of equal‐valence‐electron‐density scaling of both the experimental profiles and valence charge densities.
18Oxygen diffusion in polycrystalline lead lanthanum zirconate titanate
Authors: Hummelt Stefan , Flege Stefan , Ensinger Wolfgang 
Published: June 2010

Abstract18O oxygen tracer diffusion coefficients and activation energies were determined in polycrystalline PLZT (lead lanthanum zirconate titanate) with varying La concentration in the temperature range of 500 °C to 800 °C. For this purpose the isotope exchange method and Secondary Ion Mass Spectrometry (SIMS) depth profiling were used. As a novel approach a chemically reduced sample was prepared by anneal‐ ing at low oxygen partial pressure (p (O2) ≈ 10–13 Pa). Subsequently the sample was thermally charged with 18O, too. Results indicate a higher diffusion rate in the reduced sample than in as‐received PLZT thus leading to the assumption that the diffusion mechanism in PLZT is vacancy driven despite the strong donor doping of the perovskite lattice. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)