bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of a compact broadband circularly‐polarized slot antenna for wireless applications
Authors: Rezaeieh Sasan Ahdi , Şimşek Serkan , Pourahmadazar Javad 
Published: December 2012

AbstractThis article presents design of a compact broadband circularly‐polarized square slot antenna with a coplanar waveguide feed.A circular polarization bandwidth larger than 64.7% (3172–6211 MHz) obtained with the proposed antenna by embedding two inverted‐L grounded strips and a 45° bended strip around corners, whereas the impedance bandwidth can be greatly improved through the tuning stubs. 3 dB axial ratio bandwidth of the proposed CP antenna is large as 64.7% in a frequency band of 3172–6211 MHz. The CP antenna operates in a frequency range from 2.25 to 6.75 GHz and 8.25 to 10.25 GHz with VSWR < 2 impedance bandwidth. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:413–418, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27303
High‐performance metamaterial patch antenna
Authors: Kumar Anand , Kumar V. Dinesh 
Published: December 2012

AbstractA highly directional patch antenna with a novel fishnet metamaterial as cover has been presented at 92.4 GHz frequency. Partial substrate removal technique is used to suppress the surface wave losses. Result shows 14.91 dB improvements in gain and directionality has been improved to 3.5° as compare to 78.3° in conventional patch antenna. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:409–413, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27304
Phase noise analysis for a mm‐wave VCO configuration
Authors: George Deepa , Sinha Saurabh 
Published: December 2012

AbstractThe letter highlights the importance of modeling the phase noise of an oscillator using the impulse sensitivity function. A Colpitts oscillator in the common collector configuration is analyzed to obtain an expression for its phase noise. The oscillator design is thus optimized for phase noise with respect to process and design parameters. The fabricated voltage‐controlled oscillator at an oscillating frequency of 52.8 GHz has a measured phase noise of −98.9° dBc/Hz at 1 MHz offset. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:290–295, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27320
Design of compact and high selectivity TRI‐band wideband microstrip BPF
Authors: Deng Hong‐wei , Zhao Yong‐jiu , Zhou Xiao‐jun , Fu Yong , Liu Yan‐yun 
Published: December 2012

AbstractIn this article, a novel tri‐band wideband microstrip bandpass filter (BPF) with compact size and high selectivity is proposed using three sets of resonators, that is, λ/4 resonators, short‐stub loaded resonator, and λ/2 resonators.Each of the resonators can not only separately generate one passband, but also mainly control the passband performance. Due to the extended feed lines, parasitic coupling and intrinsic characteristics of the resonators, multiple transmission zeros can be created to improve the selectivity. A tri‐band wideband microstrip BPF centered at 2.0, 3.6, and 5.5 GHz is designed, and the predicted results are confirmed experimentally. The size is only 0.156 × 0.303 λg in which λg is the guided wavelength at 2.0 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:258–261, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27334
First normal stress difference in capillary extrusion flow of nanometer calcium carbonate‐filled PLLA biocomposites
Authors: Liang Ji‐Zhao 
Published: December 2012

AbstractThe nanometer calcium carbonate (nano‐CaCO3)‐filled poly‐L‐lactide (PLLA) biocomposites were prepared using a twin‐screw extruder. The first normal stress difference of the composites were measured by means of a capillary rheometer under experimental conditions with temperatures ranging from 170 to 200°C and shear rates varying from 50 to 103 s−1. The first normal stress difference (N1) increased roughly linearly with increasing shear stress (τw). The sensitivity of the N1 to τw increased with an increase of the die length–‐diameter ratio, and the N1 value varied slightly with the filler weight fraction (ϕf) as test temperature was constant. When the shear stress was fixed, the N1 reached a minimum value for ϕf = 1%. The values of the N1 of the composite melts decreased roughly linearly with a rise of temperature when the shear rate was constant. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Effect of EPDM‐g‐MAH on the morphology and properties of PA6/EPDM/HDPE ternary blends
Authors: Zhou Yan , Wang Wei , Dou Rui , Li Lan‐peng , Yin Bo , Yang Ming‐bo 
Published: December 2012

AbstractThe formation of core‐shell morphology within the dispersed phase was studied for composite droplet polymer‐blend systems comprising a polyamide‐6 matrix, ethylene‐propylene‐diene terpolymer (EPDM) shell and high density polyethylene (HDPE) core. In this article, the effect of EPDM with different molecular weights on the morphology and properties of the blends were studied. To improve the compatibility of the ternary blends, EPDM was modified by grafting with maleic anhydride (EPDM‐g‐MAH). It was found that core‐shell morphology with EPDM‐g‐MAH as shell and HDPE as core and separated dispersion morphology of EPDM‐g‐MAH and HDPE phase were obtained separately in PA6 matrix with different molecular weights of EPDM‐g‐MAH in the blends. DSC measurement indicated that there may be some co‐crystals in the blends due to the formation of core‐shell structure. Mechanical tests showed that PA6/EPDM‐g‐MAH/HDPE ternary blends with the core‐shell morphology exhibited a remarkable rise in the elongation at break. With more perfect core‐shell composite droplets and co‐crystals, the impact strength of the ternary blends could be greatly increased to 51.38 kJ m−2, almost 10 times higher than that of pure PA6 (5.50 kJ m−2). POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
New degradable polyesters from deoxycholic acid and oligo(ethylene glycol)s
Authors: Stanciu Magdalena C , Nichifor Marieta 
Published: December 2012

AbstractA new class of polyesters was prepared by polycondensation of a bile acid, deoxycholic acid, and an oligo(ethylene glycol) (OEG) with molar mass ranging from 100 to 1500. The chemical structure and composition of the polyesters were confirmed by 1H‐NMR, Fourier transform infrared spectroscopy and HPLC analysis. Polyester molar masses measured by gel permeation chromatography were between 5000 and 20 000. Thermal stability and glass transition temperature decreased with increasing length of OEG. Hydrolytic degradation was also enhanced by the presence of longer chain OEG. Polyesters obtained from OEG with molar mass ≥ 1000 were water soluble, semicrystalline and thermosensitive. As a function of the OEG length used for their preparation, the new polyesters can be useful for biomedical or industrial applications. © 2012 Society of Chemical Industry
Nanophosphor GdOBr:Ce via combustion synthesis: luminescence results
Authors: Blair Michael W. , Fasoli Mauro , Tornga Stephanie C. , Vedda Anna , Smith Nickolaus A. , Bennett Bryan L. , Hehlen Markus P. , Muenchausen Ross E. 
Published: December 2012

AbstractWe used combustion synthesis to produce phase pure GdOBr:Ce with varying Ce concentration. Several combinations of NH4Br and fuel concentration were tested before phase pure GdOBr:Ce was produced by using a 50% excess of NH4Br and a 50% lean concentration of fuel. In addition to the expected emissions from Ce and Gd, we also detected emissions from Eu3+ and Tb3+. Further research indicated that these extra rare earth emissions were due to impurities in the Gd2O3 starting material. While not the desired effect, we were able to monitor both Eu and Ce intensities as a function of Ce concentration in GdOBr. The Ce emission is seen to reach a maximum between 0.1 and 0.5 mol%. At higher Ce content, the Ce luminescence is quenched because of the concentration quenching effect and the higher concentration of O‐H and N‐H groups as revealed by IR spectra. Eu emission progressively decreases as Ce content increases from a combination of competition with Ce for charge capture in the RL process and the effect of OH and NH groups. As Ce concentration increases the RL intensity ratio of the bands of the Ce doublet changes even though the energy difference between the two bands (0.24 ± 0.1 eV) is compatible with the spin‐orbit splitting of the ground level of Ce3+ (0.25 eV). Fitting results indicate that this relative change is not due to changes in self‐absorption, and the effect may be due to changes in local symmetry of the Ce ion. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Substrate impact on the growth of InN nanostructures by droplet epitaxy
Authors: Kumar Mahesh , Roul Basanta , Bhat Thirumaleshwara N. , Rajpalke Mohana K. , Krupanidhi S. B. 
Published: December 2012

AbstractThe substrate effect on InN nanostructures grown by droplet epitaxy has been studied. InN nanostructures were fabricated on Si(111), silicon nitride/Si(111), AlN/Si(111) and Ge(100) substrates by droplet epitaxy using an RF plasma nitrogen source. The morphologies of InN nanostructures were investigated by field emission scanning electron microscopy (FESEM). The chemical bonding configurations of InN nanostructures were examined by x‐ray photoelectron spectroscopy (XPS). Photoluminescence spectrum slightly blue shifted compared to the bulk InN, indicating a strong Burstein–Moss effect due to the presence of high electron concentration in the InN dots (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Selectively‐sensitive metal‐semiconductor‐metal photodetectors based on AlGaN/AlN and ZnCdS/GaP heterostructures
Authors: Averin S. , Kuznetzov P. , Zhitov V. , Zakharov L. , Alkeev N. , Gladisheva N. 
Published: December 2012

AbstractWe report on the growth, fabrication and characterization of metal‐semiconductor‐metal (MSM) photodetectors based on AlGaN/AlN/Al2O3 and ZnCdS/ZnS/GaP heterostructures. The structures were grown by MOVPE at the temperatures 1050 ºC and 415 ºC respectively. Interdigital Au/Ni Schottky barrier contacts forming MSM‐diode structures were deposited on the surfaces of AlGaN and ZnCdS. The finger width and gap were 3 µm and active diode area 100x100 µm2 thus suggesting short transittimes of photogenerated carriers, low capacitance of the diode structure and high‐speed operation of the detectors. The spectral response of AlGaN MSM‐diodes demonstrates the ability of detectors for true solar‐blind response with maximum current responsivity ∼0.1 A/W at 230 nm under illumination from substrate. The I‐V curves displayed dark currents of ∼50 pA at 40 V bias. The dark current of the ZnCdS diode is much lower (∼2 pA at 40 V), which confirms the high crystalline quality of the ZnCdS‐layer (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature dependence of a‐plane GaN low angle incidence microchannel epitaxy by ammonia‐based metal‐organic molecular beam epitaxy
Authors: Naritsuka Shigeya , Lin Chia‐Hung , Uchiyama Shota , Maruyama Takahiro 
Published: December 2012

AbstractThe growth temperature dependence of a‐plane GaN produced by low angle incidence microchannel epitaxy using NH3‐based metal‐organic molecular beam epitaxy was studied. It was found that the width of the laterally grown region increased with temperature. This was because at low temperatures, {10‐12} side facets were formed, which suppressed the lateral growth process by giving rise to inter‐surface diffusion of Ga adatoms from the side to the top of the growing layer. These facets also caused the lateral growth front to assume a zigzag shape. The formation mechanism of the facets can be understood in terms of the Mullin‐Sekerka instability, by which minute periodic undulations gradually increase with growth time when their period is larger than a certain critical value, which increases with growth temperature. Defects in the epitaxial layers were also studied using transmission electron microscopy. Although the defect density was found to be very low in the laterally grown layer itself, a very large number of dislocations and stacking faults were observed both in the template layer and in the epitaxial regions above the openings. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extended defect system as a main source of non‐radiative recombination in InGaN/GaN LEDs
Authors: Shabunina Evgeniia , Averkiev Nikita , Chernyakov Anton , Levinshtein Michael , Petrov Pavel , Shmidt Natalia 
Published: December 2012

AbstractThe results of low‐frequency noise study of three sets of LEDs classified for their low voltage leakage current (LC) values are reported. The LC values at 1‐2.5 V integrally characterize electrical properties of extended defect system (EDS) that is typical for InGaN/GaN structures. The lower LC value, the smaller concentration of extended defects is. It has been shown that low‐frequency noise peculiarities such as the shape of current dependences of the noise spectral density (SI) and increase in SI with an LC values growth are caused by EDS presence. The point defects (PD) contribution to non‐radiative recombination processes is observed in current density region 10‐2 – 10 A/cm2 where radiative recombination prevails. The non‐radiative caused by EDS at j < 10‐2 A/cm2 and at j > 10 A/cm2. The complicated behavior of EDS with an injection current change has been observed (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Convective boundary layer wind dynamics and inertial oscillations: the influence of surface stress
Authors: Schröter Joel S. , Moene Arnold F. , Holtslag Albert A. M. 
Published: December 2012

AbstractInvestigating the influence of surface friction on the inertial oscillation (IO) of an extratropical, non‐growing, convective boundary layer (CBL), we paid particular attention to the stability‐dependent interactive coupling of shear‐induced turbulence and turbulent friction, which leads to a nonlinear relationship between friction and velocity. We showed that in contrast to common perception, IO damping is controlled not only by friction but also by the dependence of friction on velocity. Furthermore, we found that surface friction not only causes damping but also modifies the restoring force. Using these basic principles, we studied the oscillatory properties (equilibrium, periodicity and damping) of the CBL by means of a model based on Monin–Obukhov surface‐layer similarity (MOS) and the mixed‐layer approximation. We found that the model complies with a quadratic surface stress–velocity relationship (QS) in the neutral limit, and a linear surface stress–velocity relationship (LS) in the proximity of the free‐convective limit. Dynamically, the LS leads to a harmonic oscillation with a constant periodicity and exponential damping of the IO. However, the QS displays rather complex anharmonic behaviour; in comparison with the LS it produces a 50% stronger overall damping and a 100% larger contribution to the restoring force. Considering CBLs of arbitrary stability, we found that the MOS stress–velocity relation can be very well approximated by a much simpler linear combination of the LS and the QS which, respectively, represent the convective and the shear‐induced contributions to friction. This enabled us to link the set of the external parameters (surface roughness, surface buoyancy flux and boundary layer depth) to a set of three effective parameters: the equilibrium velocity, the convective friction constant and the neutral friction constant. Together with the Coriolis coefficient, these parameters completely determine the IO.
Neurophonetics
Authors: Hertrich Ingo , Ackermann Hermann 
Published: December 2012

AbstractNeurophonetics aims at the elucidation of the brain mechanisms underlying speech communication in our species. Clinical observations in patients with speech impairments following cerebral disorders provided the initial vantage point of this research area and indicated distinct functional‐neuroanatomic systems to support human speaking and listening. Subsequent approaches—considering speech production a motor skill—investigated vocal tract movements associated with spoken language by means of kinematic and electromyographic techniques—allowing, among other things, for the evaluation of computational models suggesting elementary phonological gestures or a mental syllabary as basic units of speech motor control. As concerns speech perception, the working characteristics of auditory processing were first investigated based upon psychoacoustic techniques such as dichotic listening and categorical perception designs. More recently, functional hemodynamic neuroimaging and electrophysiological methods opened the door to the delineation of multiple stages of central auditory processing related to signal detection, classification, sensory memory processes, and, finally, lexical access. Beyond the control mechanisms in a stricter sense, both speech articulation and auditory processing represent examples of ‘grounded cognition’. For example, both domains cannot be restricted to text‐to‐speech translation processes, but are intimately interwoven with neuropsychological aspects of speech prosody, including the vocal expression of affects and the actual performance of speech acts, transforming propositional messages to ‘real’ utterances. Furthermore, during language acquisition, the periphery of language—i.e., hearing and speaking behavior—plays a dominant role for the construction of a language‐specific mental lexicon as well as language‐specific action plans for the production of a speech message.WIREs Cogn Sci2013, 4:191–200. doi: 10.1002/wcs.1211This article is categorized under:Linguistics > Language in Mind and Brain
Early recognition of speech
Authors: Remez Robert E. , Thomas Emily F. 
Published: December 2012

AbstractClassic research on the perception of speech sought to identify minimal acoustic correlates of each consonant and vowel. In explaining perception, this view designated momentary components of an acoustic spectrum as cues to the recognition of elementary phonemes. This conceptualization of speech perception is untenable given the findings of phonetic sensitivity to modulation independent of the acoustic and auditory form of the carrier. The empirical key is provided by studies of the perceptual organization of speech, a low‐level integrative function that finds and follows the sensory effects of speech amid concurrent events. These projects have shown that the perceptual organization of speech is keyed to modulation; fast; unlearned; nonsymbolic; indifferent to short‐term auditory properties; and organization requires attention. The ineluctably multisensory nature of speech perception also imposes conditions that distinguish language among cognitive systems.WIREs Cogn Sci2013, 4:213–223. doi: 10.1002/wcs.1213This article is categorized under:Psychology > Language
The basal ganglia
Authors: Braunlich Kurt , Seger Carol 
Published: December 2012

AbstractThrough its connections with widespread cortical areas and with dopaminergic midbrain areas, the basal ganglia are well situated to integrate patterns of cortical input with the dopaminergic reward signal originating in the midbrain. In this review, we consider the functions of the basal ganglia in relation to its gross and cellular anatomy, and discuss how these mechanisms subserve the thresholding and selection of motor and cognitive processes. We also discuss how the dopaminergic reward signal enables flexible task learning through modulation of striatal plasticity, and how reinforcement learning models have been used to account for various aspects of basal ganglia activity. Specifically, we will discuss the important role of the basal ganglia in instrumental learning, cognitive control, sequence learning, and categorization tasks. Finally, we will discuss the neurobiological and cognitive characteristics of Parkinson's disease, Huntington's disease and addiction to illustrate the relationship between the basal ganglia and cognitive function. WIREs Cogn Sci 2013, 4:135–148. doi: 10.1002/wcs.1217This article is categorized under:

Neuroscience > Anatomy
Synthesis, Structures, and Properties of New Discrete Hetero‐tetranuclear Metallocycle Complexes Based on Macrocyclic Oxamide Metalloligands
Authors: Shi Xiao‐Ming , Li Xiao‐Zeng , Ding Bei‐Bei , Zhu Li‐Na 
Published: December 2012

AbstractTwo new discrete hetero‐tetranuclear metallocycle complexes based on metalloligands, {[Zn2(NiL1)2(H2O)6]·4H2O}n (1) and {[Ca2(NiL2)2(CH3OH)0.5(H2O)7]·CH3OH·2H2O}n (2) were synthesized under self‐assembly conditions and structurally determined. X‐ray diffraction analyses revealed that the two compounds involve the discrete metallocyclic units, which serve as building blocks to further expand to three‐dimensional supramolecular frameworks through second interactions such as hydrogen bonds and π···π stacking interactions. The central ZnII and CaII ions of the compounds 1 and 2 are bridged by macrocyclic oxamido metalloligands fusing the metallocycle with “head‐to‐tail” arrangement. The metallocycles have Zn···Zn distances of 9.48 Å in 1 and Ca···Ca distances of 9.90 Å in 2. Further, compounds 1 and 2 were investigated by thermogravimetric analysis.
Expanding the reach of youth mentoring: Partnering with youth for personal growth and social change
Authors: Liang Belle , Spencer Renée , West Jennifer , Rappaport Nancy 
Published: December 2012

ABSTRACTThe goals of youth mentoring have broadened from redressing youth problems to promoting positive youth development. Yet, many of the principles associated with contemporary conceptualizations of development found in the positive youth development (PYD) and community psychology (CP) literature have yet to be fully integrated into mentoring research and practice. These approaches place greater emphasis on youth as assets to their communities and the promotion of positive development through the cultivation of these assets, often by fostering collaborative partnerships between youth and adults to effect social change. In this paper, we examine how bringing these systemic, asset‐oriented approaches more fully to bear on the youth mentoring process creates opportunities that may both extend the reach and deepen the impact of youth mentoring through the promotion of community, social, and individual change.
Correlates of long‐term participation in a physical activity‐based positive youth development program for low‐income youth: Sustained involvement and psychosocial outcomes
Authors: Ullrich‐French Sarah , McDonough Meghan H. 
Published: December 2012

ABSTRACTThis study examined correlates of long‐term participation in a positive youth development (PYD) program. Low‐income youth (N = 215) age 8–13 of diverse ethnicity participating in a summer physical activity‐based PYD program completed questionnaires at the beginning and end of the program (year 1) and at the beginning of year 2. Those with lower BMI and higher attendance and leader support perceptions were more likely to return to the program the following year. Self‐worth and leader support perceptions at time 2 were higher for returners compared to non‐returners. Among returners, hope increased from year 1 to year 2 and increases in global self‐worth across the first year were maintained over one year. Social support is linked to continued PYD participation. Returners had increased and/or sustained positive perceptions of self‐worth and hope. Programs are encouraged to foster staff–participant relationships and self‐worth, and minimize barriers associated with weight status.
Clinical Issues
Authors: Maxwell‐Downing Denise 
Published: December 2012

This MonthPatient safety during the transition from paper to electronic health recordsKey words: electronic health record (EHR), documentation, paper documentation, electronic documentation, patient safety.Documentation needed for transitions from paper to electronic health recordsKey words: electronic health record (EHR), paper documentation, documentation.The meaning of electronic health record interoperabilityKey words: standardized nursing language, interoperability, Perioperative Nursing Data Set (PNDS).