bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel fluorescence probe for estimation of cysteine/histidine in human blood plasma and recognition of endogenous cysteine in live Hct116 cells
Authors: G. Upendar Reddy , Agarwalla Hridesh , Taye Nandaraj , Ghorai Suvankar , Chattopadhyay Samit , Das Amitava
Published: July 2014

A new cell membrane permeable reagent for detection of endogenous Cys as well as quantitative estimation of Cys and His in a human blood plasma sample.
Rhodium-catalyzed direct synthesis of unprotected NH-sulfoximines from sulfoxides
Authors: Miao Jinmin , Richards Nigel G. J. , Ge Haibo
Published: July 2014

A novel rhodium–catalyzed imination of sulfoxides using O-(2,4-dinitrophenyl)hydroxylamine is developed under mild conditions with good functional group tolerance.
Proton dynamics of two-dimensional oxalate-bridged coordination polymers
Authors: Miyatsu Satoshi , Kofu Maiko , Nagoe Atsushi , Yamada Takeshi , Sadakiyo Masaaki , Yamada Teppei , Kitagawa Hiroshi , Tyagi Madhusudan , García Sakai Victoria , Yamamuro Osamu
Published: July 2014

The dynamics of H2O molecules and NH4+ ions in a new type of crystalline proton conductor (NH4)2(adp)[Zn2(ox)3]·3H2O has been investigated by quasielastic neutron scattering techniques to elucidate the proton conduction mechanism.
Reversible addition of the OH radical top-cymene in the gas phase: multiple adduct formation. Part 2
Authors: Alarcón Paulo , Bohn Birger , Zetzsch Cornelius , Rayez Marie-Thérèse , Rayez Jean-Claude
Published: July 2014

Four adduct isomers can be formed in the OH +p-cymene reaction. Experiments reveal formation of at least two distinguishable adducts in agreement with theoretical predictions that mainly the twoortho-adducts are formed.
Morphological effects of the nanostructured ceria support on the activity and stability of CuO/CeO2 catalysts for the water-gas shift reaction
Authors: Yao S. Y. , Xu W. Q. , Johnston-Peck A. C. , Zhao F. Z. , Liu Z. Y. , Luo S. , Senanayake S. D. , Martínez-Arias A. , Liu W. J. , Rodriguez J. A.
Published: July 2014

A detailed in operando study of the morphological effects of nanostructured ceria supports on the activity and stability of CuO/CeO2 catalysts for the water-gas shift reaction.
Coupling reaction between CO2 and cyclohexene oxide: selective control from cyclic carbonate to polycarbonate by ligand design of salen/salalen titanium complexes
Authors: Wang Yong , Qin Yusheng , Wang Xianhong , Wang Fosong
Published: July 2014

Selective control from cyclic carbonate to polycarbonate by ligand design of salen/salalen titanium complexes.
Anion templating from a silver(i) dithiophosphate 1D polymer forming discrete cationic and neutral octa- and decanuclear silver(i) clusters
Authors: Liao Jian-Hong , Chang Hao-Wei , Li Yi-Juan , Fang Ching-Shiang , Sarkar Bijay , van Zyl Werner E. , Liu C. W.
Published: July 2014

The polymer [Ag5{S2P(OiPr)2}4]n(PF6)nforms discrete Ag8and Ag10clusters with encapsulated anions; the nuclearity depends on the M : L stoichiometric control.
Sulfonic acid-functionalized silica-coated magnetic nanoparticles as an efficient reusable catalyst for the synthesis of 1-substituted 1H-tetrazoles under solvent-free conditions
Authors: Naeimi Hossein , Mohamadabadi Samaneh
Published: July 2014

Regarding green chemistry goals, silica-coated magnetite nanoparticles open up a new avenue to introduce a very useful and efficient system for facilitating catalyst recovery in different organic reactions.
Role of edge geometry and chemistry in the electronic properties of graphene nanostructures
Authors: Fujii Shintaro , Ziatdinov Maxim , Ohtsuka Misako , Kusakabe Koichi , Kiguchi Manabu , Enoki Toshiaki
Published: July 2014

The geometry and chemistry of graphene nanostructures significantly affects their electronic properties. Despite a large number of experimental and theoretical studies dealing with the geometrical shape-dependent electronic properties of graphene nanostructures, experimental characterisation of their chemistry is clearly lacking. This is mostly due to the difficulties in preparing chemically-modified graphene nanostructures in a controlled manner and in identifying the exact chemistry of the graphene nanostructure on the atomic scale. Herein, we present scanning probe microscopic and first-principles characterisation of graphene nanostructures with different edge geometries and chemistry. Using the results of atomic scale electronic characterisation and theoretical simulation, we discuss the role of the edge geometry and chemistry on the electronic properties of graphene nanostructures with hydrogenated and oxidised linear edges at graphene boundaries and the internal edges of graphene vacancy defects. Atomic-scale details of the chemical composition have a strong impact on the electronic properties of graphene nanostructures,i.e., the presence or absence of non-bonding π states and the degree of resonance stability.
ICP-MS method for Pu and Np isotopes in population monitoring by a micro-flow injection sample introduction system
Authors: Shi Youqing , Dai Xiongxin , Li Chunsheng , Collins Roxanne , Kramer-Tremblay Sheila , Riopel Remi , Broome Carrie
Published: July 2014

A micro-flow injection ICP-MS method was applied to radiological emergency monitoring of Plutonium and Neptunium.
Enhanced catalytic activity of polyethylenedioxythiophene towards tri-iodide reduction in DSSCs via 1-dimensional alignment using hollow carbon nanofibers
Authors: Anothumakkool Bihag , Game Onkar , Bhange Siddheshwar N. , Kumari Tanya , Ogale Satishchandra B. , Kurungot Sreekumar
Published: July 2014

1-D aligned polyethylenedioxythiophene inside and outside of a hollow carbon nanofiber as a counter electrode in a dye sensitized solar cell with an efficiency of 7.16%.
Controllable copper deficiency in Cu2−xSe nanocrystals with tunable localized surface plasmon resonance and enhanced chemiluminescence
Authors: Lie Shao Qing , Wang Dong Mei , Gao Ming Xuan , Huang Cheng Zhi
Published: July 2014

We developed a new surfactant assisted route to prepare size-controlled Cu2−xSe NCs with a controllable copper deficiency, which had strong localized surface plasmon resonance and excellent catalytic activity.
Environment-dependent photon emission from solid state carbon dots and its mechanism
Authors: Deng Yehao , Chen Xing , Wang Fei , Zhang Xueao , Zhao Dongxu , Shen Dezhen
Published: July 2014

The interaction between polar groups and carbon dots is found to be the mechanism of environment-dependent blue emission.
Hybrid inverse opals for regulating cell adhesion and orientation
Authors: Lu Jie , Zheng Fuyin , Cheng Yao , Ding Haibo , Zhao Yuanjin , Gu Zhongze
Published: July 2014

Hybrid inverse opal substrates with tunable patterned nanostructures were developed for regulating the cell behaviors of adhesion and alignment.
Tunable T1 and T2 contrast abilities of manganese-engineered iron oxide nanoparticles through size control
Authors: Huang Guoming , Li Hui , Chen Jiahe , Zhao Zhenghuan , Yang Lijiao , Chi Xiaoqin , Chen Zhong , Wang Xiaomin , Gao Jinhao
Published: July 2014

Uniform manganese-doped iron oxide (MnIO) nanoparticles with controllable size from 5 to 12 nm were synthesized and their size-dependent MRI contrast abilities were investigated.
Studying the mechanism of CD47–SIRPα interactions on red blood cells by single molecule force spectroscopy
Authors: Pan Yangang , Wang Feng , Liu Yanhou , Jiang Junguang , Yang Yong-Guang , Wang Hongda
Published: July 2014

The interactions between SIRPα and CD47 were investigated by single-molecule force spectroscopy on both fresh and experimentally aged hRBCs. CD47 experienced a conformation change after oxidation, which may determine the CD47–SIRPα signalling switch on the phagocytosis of hRBCs.
Ultra-high capacitance hematite thin films with controlled nanoscopic morphologies
Authors: Liu Jingling , Lee Eunjik , Kim Yong-Tae , Kwon Young-Uk
Published: July 2014

Humidity-dependent hematite thin films with two different ultrathin nanoscopic morphologies have been synthesized for remarkable capacitances.
Ultrathin cellulose nanosheet membranes for superfast separation of oil-in-water nanoemulsions
Authors: Zhou Ke , Zhang Qiu Gen , Li Hong Mei , Guo Nan Nan , Zhu Ai Mei , Liu Qing Lin
Published: July 2014

Ultrathin cellulose nanosheet membranes are fabricated via a facile and green approach. They show ultrafast separation of oil-in-water nanoemulsions and have wide applications in wastewater treatment.
Systemic gene silencing in plants triggered by fluorescent nanoparticle-delivered double-stranded RNA
Authors: Jiang Li , Ding Lian , He Bicheng , Shen Jie , Xu Zejun , Yin Meizhen , Zhang Xiaolan
Published: July 2014

A cationic fluorescence nanoparticle efficiently enters plants with high transfection efficacy.
Total synthesis of fluoxetine and duloxetine through an in situ imine formation/borylation/transimination and reduction approach
Authors: Calow Adam D. J. , Fernández Elena , Whiting Andrew
Published: July 2014

Efficient, catalytic, asymmetric total syntheses of both (R)-fluoxetine and (S)-duloxetine from α,β-unsaturated aldehydes are reported.
Eco-efficient and green method for the enhanced dissolution of aromatic crude oil sludge using ionic liquids
Authors: Sakthivel Sivabalan , Velusamy Sugirtha , Gardas Ramesh L. , Sangwai Jitendra S.
Published: July 2014

Proposed mechanism for the enhancement in the dissolution of aromatic TBS in solvents in the presence of aromatic ionic liquids.
Studies on application of fish waste for synthesis of high quality biodiesel
Authors: Madhu Devarapaga , Singh Bhaskar , Sharma Yogesh C.
Published: July 2014

A low cost raw material obtained from the discarded parts of fish (Cirrhinus mrigala, Cirrhinus cirrhosa, Cirrhinus reba) was utilized as feedstock oil and catalyst for the synthesis of biodiesel.
Synthesis, biological evaluation, and molecular docking studies of novel chalcone oxime derivatives as potential tubulin polymerization inhibitors
Authors: Wang Yan-Ting , Qin Ya-Juan , Zhang Ya-Liang , Li Yu-Jing , Rao Bing , Zhang Yan-Qing , Yang Meng-Ru , Jiang Ai-Qin , Qi Jin-Liang , Zhu Hai-Liang
Published: July 2014

Compounds of novel chalcone oxime derivatives containing different substituent groups were designed, synthesized and evaluated for the inhibitory activity against tubulin polymerization and cancer cell inhibitory activity.
Inflammatory modulation of stem cells by Magnetic Resonance Imaging (MRI)-detectable nanoparticles
Authors: Aday Sezin , Paiva Jose , Sousa Susana , Gomes Renata S. M. , Pedreiro Susana , So Po-Wah , Carr Carolyn Ann , Cochlin Lowri , Gomes Ana Catarina , Paiva Artur , Ferreira Lino
Published: July 2014

Novel MRI-detectable PLGA nanoparticles can track hematopoietic stem cells and down-regulate the secretion of pro-inflammatory cytokines by interfering with TLRs.
Cotton-based hollow carbon fibers with high specific surface area prepared by ammonia etching for supercapacitor application
Authors: Wang Shuguang , Ren Zhonghua , Li Jianpeng , Ren Yaqi , Zhao Lei , Yu Jie
Published: July 2014

In this paper, carbon fibers with a high specific surface area (SSA) have been prepared from cotton for supercapacitor application.
Detection of molecular binding via charge-induced mechanical response of optical fibers
Authors: Guan Yan , Shan Xiaonan , Wang Shaopeng , Zhang Peiming , Tao Nongjian
Published: July 2014

We report a charge sensitive optical detection technique for the label-free study of molecular interactions.
Deciphering the structure–immunogenicity relationship of anti-Candidaglycoconjugate vaccines
Authors: Adamo Roberto , Hu Qi-Ying , Torosantucci Antonella , Crotti Stefano , Brogioni Giulia , Allan Martin , Chiani Paola , Bromuro Carla , Quinn Douglas , Tontini Marta , Berti Francesco
Published: July 2014

Elucidation of the molecular immunity of glycoconjugate vaccines has focused on the carbohydrate moiety, herein the effect of the corresponding conjugation sites is studied.
Structural, electronic and thermoelectric behaviour of CaMnO3 and CaMnO(3−δ)
Authors: Molinari Marco , Tompsett David A. , Parker Stephen C. , Azough Feridoon , Freer Robert
Published: July 2014

The thermoelectric properties, including ZT, of stoichiometric and reduced phases of the orthorhombic perovskite CaMnO3 were evaluated using DFT.
Performance enhancement of single-walled nanotube–microwave exfoliated graphene oxide composite electrodes using a stacked electrode configuration
Authors: Antiohos Dennis , Romano Mark S. , Razal Joselito M. , Beirne Stephen , Aitchison Phil , Minett Andrew I. , Wallace Gordon G. , Chen Jun
Published: July 2014

Optimised SWNTs/MW-rGO supercapacitor in a stacked electrode configuration, leading to an enhancement of energy density.
Synthesis of 6H-benzo[c]chromene as a new electron-rich building block of conjugated alternating copolymers and its application to polymer solar cells
Authors: Lee Jong Won , Bae Seunghwan , Jo Won Ho
Published: July 2014

PBCDTBTandPBCDPP2Tare synthesized by introducing an oxygen atom in the fluorene unit inPFDTBTandPFDPP2T, respectively.PBCDTBT- andPBCDPP2T-based devices exhibit higherJSCs thanPFDTBTandPFDPP2T-based devices, respectively.
The studies on highly concentrated complex dispersions of gold nanoparticles and temperature-sensitive nanogels and their application as new blood-vessel-embolic materials with high-resolution angiography
Authors: Ma Yingying , Wan Jiangshan , Qian Kun , Geng Shinan , He Nijun , Zhou Guofeng , Zhao Yanbing , Yang Xiangliang
Published: July 2014

High colloid stability of highly concentrated Au nanoparticles (GNPs) for use in blood-pool imaging was achieved, using p(N-isopropylacrylamide-co-butyl methylacrylate) nanogels.
Redox-responsive nanoreservoirs based on collagen end-capped mesoporous hydroxyapatite nanoparticles for targeted drug delivery
Authors: Li Dalong , He Jinmei , Cheng Weilu , Wu Yadong , Hu Zhen , Tian Huayu , Huang Yudong
Published: July 2014

Schematic illustration of a redox-responsive system based on collagen-capped MHAp for cell-targeted drug delivery.
Trypanosoma brucei eflornithine transporter AAT6 is a low-affinity low-selective transporter for neutral amino acids
Authors: Mathieu Christoph , Salgado Amaia González , Wirdnam Corina , Meier Stefan , Grotemeyer Marianne Suter , Inbar Ehud , Mäser Pascal , Zilberstein Dan , Sigel Erwin , Bütikofer Peter , Rentsch Doris
Published: July 2014

Amino acid transporters are crucial for parasite survival since the cellular metabolism of parasitic protozoa depends on the up-take of exogenous amino acids. Amino acid transporters are also of high pharmacological relevance because they may mediate uptake of toxic amino acid analogues. In the present study we show that the eflornithine transporter AAT6 from Trypanosoma brucei (TbAAT6) mediates growth on neutral amino acids when expressed in Saccharomyces cerevisiae mutants. The transport was electrogenic and further analysed in Xenopus laevis oocytes. Neutral amino acids, proline analogues, eflornithine and acivicin induced inward currents. For proline, glycine and tryptophan the apparent affinities and maximal transport rates increased with more negative membrane potentials. Proline-induced currents were dependent on pH, but not on sodium. Although proline represents the primary energy source of T. brucei in the tsetse fly, down-regulation of TbAAT6-expression by RNAi showed that in culture TbAAT6 is not essential for growth of procyclic form trypanosomes in the presence of glucose or proline as energy source. TbAAT6-RNAi lines of both bloodstream and procyclic form trypanosomes showed reduced susceptibility to eflornithine, whereas the sensitivity to acivicin remained unchanged, indicating that acivicin enters the cell by more than one transporter.
Addressing Children's Communication Needs
Authors: Nippold Marilyn A.
Published: July 2014

Purpose

In this column, the editor gives an overview of each article in the current issue of
Language
,
Speech, and Hearing Services in Schools
(Vol. 45, No. 3).
Resonance based zero‐voltage zero‐current switching full bridge converter
Authors: Karimi Rouhollah , Adib Ehsan , Farzanehfard Hosein
Published: July 2014

A zero‐voltage and zero‐current switching full bridge converter with series resonance tank is presented in this study. This converter is based on standard full bridge topology and a series capacitor is added in the primary side to reset the leakage inductance current without any additional auxiliary circuit. Leakage inductance of the transformer is used as the resonance inductance. Using series resonance tank and applying control pulses with fix frequency, zero‐voltage switching for leading leg and zero‐current switching for lagging leg is achieved. The output power is controlled using phase shift technique. In the proposed converter, soft‐switching condition is attained for wide range of load variation. Due to its high performance and minimum additional components with respect to regular converter, this converter can be applied for medium to high‐power applications. Topology and operating modes are discussed and the validity of theoretical analysis is verified by prototype experimental results.
Simple peak detection control algorithm of distribution static compensator for power quality improvement
Authors: Singh Bhim , Arya Sabha Raj , Jain Chinmay
Published: July 2014

This study deals with the control of a three‐phase, four‐wire distribution static compensator (DSTATCOM) based on the peak detection of load currents for power quality improvement under linear/non‐linear loads. This control algorithm is simple and easy in real time implementation. In this control algorithm, an extraction of active and reactive power components of load currents is based on a low‐pass filter and the voltage unit vector in time domain. It is based on the mathematical formulations for fast and accurate estimation of reference supply currents. A four‐wire DSTATCOM is modelled and implemented for the compensation of linear and non‐linear loads using a digital signal processor. Performance of DSTATCOM is found quite satisfactory under balanced and unbalanced loads in three‐phase, four‐wire distribution system.
A new switching strategy for transformer‐less back‐to‐back cascaded H‐bridge multilevel converter
Authors: Miranbeigi Mohammadreza , Iman‐Eini Hossein , Asoodar Mohsen
Published: July 2014

In this study, a new switching strategy is introduced for transformer‐less back‐to‐back cascaded H‐bridge (CHB) converters. The main purpose of this novel switching algorithm is to eliminate the need for an isolation stage between the line side and the load side H‐bridge cells. In other words, using this strategy, the CHB rectifier and the CHB inverter can be connected directly to each other in a back‐to‐back structure. The CHB rectifier regulates the intermediate DC bus voltages to the reference value, whereas the CHB inverter generates a controllable AC voltage from the intermediate DC links. The low‐frequency selective harmonic elimination technique is applied to eliminate specific harmonics from the output voltage and to minimise the switching loss. The validity and effectiveness of the proposed method are verified by simulations and experiments on a five‐level back‐to‐back converter.
Analysis and implementation of a new single‐switch buck–boost DC/DC converter
Authors: Banaei Mohammad Reza , Ardi Hossein , Farakhor Amir
Published: July 2014

In this study, a novel buck–boost DC/DC converter is presented. The circuit structure of the proposed converter consists of a single power switch, two diodes and some energy storage elements. Employing only a single power switch reduces the implementation cost and switching power losses. The proposed converter has higher voltage gain in step‐up mode in comparison with conventional buck–boost and Cuk converter. In addition, this converter expands the continuous conduction mode (CCM) operational region. The presented converter has three operation modes in CCM. The second mode reduces the voltage stresses across the capacitors. Therefore the current stresses on diodes are also reduced. To verify the operation of the proposed converter, the experimental results are provided using a hardware prototype.
Nonreciprocal and magnetically scanned miniaturized leaky-wave antennas using coupled transmission lines
Authors: Apaydin Nil , Sertel Kubilay , Volakis John L.
Published: July 2014

This paper presents a new class of magnetically scanned leaky wave antennas (LWAs), incorporating ferrite (or possibly magnetoelectric composite), for wide angle beamsteering. Using the ferrite’s tunable permeability beamsteering is achieved by controlling the external bias field. This is unlike most leaky-wave antennas requiring frequency modulation to steer the beam. Our first design is based on coupled microstrip lines on a biased ferrite substrate with nonreciprocal radiation properties, specifically a 5 dB contrast between the measured transmit and receive gain in the E-plane was achieved. However, it was found that inhomogeneities in the bias field limited its scanning performance. To alleviate this issue, a new class of miniaturized metamaterial based LWA was considered and presented here. This new design is based on coupled composite right left handed (CRLH) transmission lines (TLs) and has a unit-cell length of only λ0/20. For validation, a 15-unit-cell prototype was manufactured and its TX/RX beams were scanned in the E-plane 80° by changing the bias field within a range of ±50 Oe. We found that the associated antenna gain varied between 3.5 dB and 5 dB at 1.79 GHz as the beam was scanned. In the above design, scanning was realized by changing the distance between the bias source and the LWA. Thus, future work will be focused on LWAs tuned by biasing a magnetodielectric layer placed below the ferrite substrate.
The demonstration of colossal magneto-capacitance effect with the promising gate stack characteristics on Ge (100) by the magnetic gate stack design
Authors: Liao M.-H. , Huang S.-C.
Published: July 2014

The tetragonal-phase BaTiO3 as the high dielectric (HK) layer and the magnetic FePt film as the metal gate (MG) are proposed to be the gate stack scheme on the Ge (100) substrate. The ∼75% dielectric constant (κ-value) improvement, ∼100X gate leakage (Jg) reduction, and the promising Jg-equivalent-oxide-thickness (EOT) gate stack characteristics are achieved in this work with the colossal magneto-capacitance effect. The perpendicular magnetic field from the magnetic FePt MG film couples and triggers the more dipoles in the BaTiO3 HK layer and then results in the super gate capacitance (Cgate) and κ-value. Super Jg-EOT gate stack characteristics with the magnetic gate stack design on the high mobility (Ge) substrate demonstrated in this work provides the useful solution for the future low power mobile device design.
Voltage induced magnetostrictive switching of nanomagnets: Strain assisted strain transfer torque random access memory
Authors: Khan Asif , Nikonov Dmitri E. , Manipatruni Sasikanth , Ghani Tahir , Young Ian A.
Published: July 2014

A spintronic device, called the “strain assisted spin transfer torque (STT) random access memory (RAM),” is proposed by combining the magnetostriction effect and the spin transfer torque effect which can result in a dramatic improvement in the energy dissipation relative to a conventional STT-RAM. Magnetization switching in the device which is a piezoelectric-ferromagnetic heterostructure via the combined magnetostriction and STT effect is simulated by solving the Landau-Lifshitz-Gilbert equation incorporating the influence of thermal noise. The simulations show that, in such a device, each of these two mechanisms (magnetostriction and spin transfer torque) provides in a 90° rotation of the magnetization leading a deterministic 180° switching with a critical current significantly smaller than that required for spin torque alone. Such a scheme is an attractive option for writing magnetic RAM cells.
2D image of local density and magnetic fluctuations from line-integrated interferometry-polarimetry measurements
Authors: Lin L. , Ding W. X. , Brower D. L.
Published: July 2014

Combined polarimetry-interferometry capability permits simultaneous measurement of line-integrated density and Faraday effect with fast time response (∼1 μs) and high sensitivity. Faraday effect fluctuations with phase shift of order 0.05° associated with global tearing modes are resolved with an uncertainty ∼0.01°. For physics investigations, local density fluctuations are obtained by inverting the line-integrated interferometry data. The local magnetic and current density fluctuations are then reconstructed using a parameterized fit of the polarimetry data. Reconstructed 2D images of density and magnetic field fluctuations in a poloidal cross section exhibit significantly different spatial structure. Combined with their relative phase, the magnetic-fluctuation-induced particle transport flux and its spatial distribution are resolved.
Methods for determining piezoelectric properties of thin epitaxial films: Theoretical foundations
Authors: McCartney L. N. , Wright L. , Cain M. G. , Crain J. , Martyna G. J. , Newns D. M.
Published: July 2014

An analytical method is developed to determine piezoelectric properties of a thin film directly from measurements of bilayer deflection. As a significant extension to previous approaches, we include here the effects of bilayer bending, differential thermal expansion, and epitaxial lattice mismatch which commonly arise in practical measurements. The formulation reported here thus relaxes restrictive assumptions made in previous models thereby enabling a more direct link with experimental conditions. The model, which has been validated by comparison with finite element analysis, is shown to reduce to the well-known Lefki-Dormans result as a limiting case for thin films when bending and in-plane deformations are neglected. If the curvature of a simply supported bilayer can be measured, then the model offers a methodology for measuring the piezoelectric properties (ε33T,  d31,  d33), the film elastic constant s11E+s12E, and lattice mismatch strains, provided a value of the elastic constant s13E can be determined or estimated. If curvature measurements are not available but lattice mismatch strains are known, then we find that it is still possible to measure these piezoelectric and elastic film properties.
Analyzing the errors of DFT approximations for compressed water systems
Authors: Alfè D. , Bartók A. P. , Csányi G. , Gillan M. J.
Published: July 2014

We report an extensive study of the errors of density functional theory (DFT) approximations for compressed water systems. The approximations studied are based on the widely used PBE and BLYP exchange-correlation functionals, and we characterize their errors before and after correction for 1- and 2-body errors, the corrections being performed using the methods of Gaussian approximation potentials. The errors of the uncorrected and corrected approximations are investigated for two related types of water system: first, the compressed liquid at temperature 420 K and density 1.245 g/cm3 where the experimental pressure is 15 kilobars; second, thermal samples of compressed water clusters from the trimer to the 27-mer. For the liquid, we report four first-principles molecular dynamics simulations, two generated with the uncorrected PBE and BLYP approximations and a further two with their 1- and 2-body corrected counterparts. The errors of the simulations are characterized by comparing with experimental data for the pressure, with neutron-diffraction data for the three radial distribution functions, and with quantum Monte Carlo (QMC) benchmarks for the energies of sets of configurations of the liquid in periodic boundary conditions. The DFT errors of the configuration samples of compressed water clusters are computed using QMC benchmarks. We find that the 2-body and beyond-2-body errors in the liquid are closely related to similar errors exhibited by the clusters. For both the liquid and the clusters, beyond-2-body errors of DFT make a substantial contribution to the overall errors, so that correction for 1- and 2-body errors does not suffice to give a satisfactory description. For BLYP, a recent representation of 3-body energies due to Medders, Babin, and Paesani [J. Chem. Theory Comput. 9, 1103 (2013)] gives a reasonably good way of correcting for beyond-2-body errors, after which the remaining errors are typically 0.5 mEh ≃ 15 meV/monomer for the liquid and the clusters.
Stabilization of antiferromagnetic phase under hydrostatic pressure in layered perovskite cobaltites Nd1-xCaxBaCo2O5.5 (x = 0–0.06)
Authors: Pietosa J. , Szewczyk A. , Puzniak R. , Wisniewski A. , Dabrowski B. , Kolesnik S.
Published: July 2014

Magnetic measurements have been performed under pressure of 0–9.7 kbar and in the temperature range of 5–300 K for the hole-doped Nd1-xCaxBaCo2O5.5 system over the composition range x = 0–0.06, where a strong competition between antiferromagnetic and ferrimagnetic phases is present. The dependence of TN, i.e., of the temperature of a first order phase transition from the antiferromagnetic to the ferrimagnetic state, and of TC, i.e., of the temperature of the second order phase transition from the ferrimagnetic to the paramagnetic state on hydrostatic pressure was found to be a function of hole doping. The large pressure-induced increase of TN becomes enhanced with increasing of the hole doping level, while a small pressure-induced increase of TC is suppressed by increasing the hole doping level. This finding shows that the hydrostatic pressure stabilizes the antiferromagnetic phase, whereas the hole doping alone suppresses the antiferromagnetic phase. All investigated compounds have revealed the existence of a certain fraction of ferrimagnetic phase at temperatures much below TN. An increase of a magnetization observed in high magnetic field of 50 kOe at temperatures much below TN was explained as the high-field induced polarization of Nd3+ magnetic moments, appearing in the magnetic field exceeding the strength of Nd-Co antiferromagnetic exchange interactions.
Surface loss probability of atomic hydrogen for different electrode cover materials investigated in H2-Ar low-pressure plasmas
Authors: Sode M. , Schwarz-Selinger T. , Jacob W. , Kersten H.
Published: July 2014

In an inductively coupled H2-Ar plasma at a total pressure of 1.5 Pa, the influence of the electrode cover material on selected line intensities of H, H2, and Ar are determined by optical emission spectroscopy and actinometry for the electrode cover materials stainless steel, copper, tungsten, Macor®, and aluminum. Hydrogen dissociation degrees for the considered conditions are determined experimentally from the measured emission intensity ratios. The surface loss probability βH of atomic hydrogen is correlated with the measured line intensities, and βH values are determined for the considered materials. Without the knowledge of the atomic hydrogen temperature, βH cannot be determined exactly. However, ratios of βH values for different surface materials are in first order approximation independent of the atomic hydrogen temperature. Our results show that βH of copper is equal to the value of stainless steel, βH of Macor® and tungsten is about 2 times smaller and βH of aluminum about 5 times smaller compared with stainless steel. The latter ratio is in reasonable agreement with literature. The influence of the atomic hydrogen temperature TH on the absolute value is thoroughly discussed. For our assumption of TH = 600 K, we determine a βH for stainless steel of 0.39 ± 0.13.
Influences of periodic mechanical deformation on pinned spiral waves
Authors: Chen Jiang-Xing , Peng Liang , Zheng Qiang , Zhao Ye-Hua , Ying He-Ping
Published: July 2014

In a generic model of excitable media, we study the behavior of spiral waves interacting with obstacles and their dynamics under the influences of simple periodic mechanical deformation (PMD). Depending on the characteristics of the obstacles, i.e., size and excitability, the rotation of a pinned spiral wave shows different scenarios, e.g., embedding into or anchoring on an obstacle. Three different drift phenomena induced by PMD are observed: scattering on small partial-excitable obstacles, meander-induced unpinning on big partial-excitable obstacles, and drifting around small unexcitable obstacles. Their underlying mechanisms are discussed. The dependence of the threshold amplitude of PMD on the characteristics of the obstacles to successfully remove pinned spiral waves on big partial-excitable obstacles is studied.
Floating potential of large dust grains with electron emission
Authors: Bacharis M.
Published: July 2014

Electron emission from the surface of solid particles plays an important role in many dusty plasma phenomena and applications. Examples of such cases include fusion plasmas and dusty plasma systems in our solar system. Electron emission complicates the physics of the plasma-dust interaction. One of the most important aspects of the physics of the dust plasma interaction is the calculation of the particle's floating potential. This is the potential a dust particle acquires when it is in contact with a plasma and it plays a very important role for determining its dynamical behaviour. The orbital motion limited (OML) approach is used in most cases in the literature to model the dust charging physics. However, this approach has severe limitations when the size of the particles is larger than the electron Debye length λDe. Addressing this shortcoming for cases without electron emission, a modified version of OML (MOML) was developed for modelling the charging physics of dust grains larger than the electron Debye length. In this work, we will focus on extending MOML in cases where the particles emit electrons. Furthermore, a general method for calculating the floating potential of dust particles with electron emission will be presented for a range of grain sizes.
Role of defects in determining the electrical properties of ZnO ceramics
Authors: Zhao Xuetong , Liao Ruijin , Liang Ningchuan , Yang Lijun , Li Jian , Li Jianying
Published: July 2014

A greatly enhanced breakdown electric field of ∼8 kV/cm was achieved in multi-doping ZnO ceramics, and the role of defects in determining the electrical properties were systematically investigated in this work. At low temperature of around 203 K, it is found that the dielectric loss is composed of dc conduction and two defect relaxation peaks with activation energy at 0.24 eV and 0.37 eV, which can be effectively described according to Debye relaxation theory. At high temperature of 473 K, anther two defect relaxation peaks with activation energy at 0.65 eV and 0.98 eV are found to obey Cole-Davidson function, which are greatly affected by additives and closely related to the electrical properties of ZnO ceramics. Additionally, impedance analysis shows that the grain boundary resistance of ZnO ceramics is increased from 0.56 MΩ to 15.7 MΩ at 473 K and the corresponding activation energy of grain boundary is elevated from 0.23 eV to 1.03 eV. The frequency dependence of the conductivity is interpreted with the Jonscher's law, which indicates that the contribution of dc conduction at low frequency can be evidently suppressed by additives. An equivalent circuit model is demonstrated for expounding the association between enhanced electrical properties and defect relaxation in ZnO ceramics.
Semipolar (202¯1) GaN and InGaN quantum wells on sapphire substrates
Authors: Leung Benjamin , Wang Dili , Kuo Yu-Sheng , Xiong Kanglin , Song Jie , Chen Danti , Park Sung Hyun , Hong Su Yeon , Choi Joo Won , Han Jung
Published: July 2014

Here, we demonstrate a process to produce planar semipolar (202¯1) GaN templates on sapphire substrates. We obtain (202¯1) oriented GaN by inclined c-plane sidewall growth from etched sapphire, resulting in single crystal material with on-axis x-ray diffraction linewidth below 200 arc sec. The surface, composed of (101¯1) and (101¯0) facets, is planarized by the chemical-mechanical polishing of full 2 in. wafers, with a final surface root mean square roughness of <0.5 nm. We then analyze facet formation and roughening mechanisms on the (202¯1) surface and establish a growth condition in N2 carrier gas to maintain a planar surface for further device layer growth. Finally, the capability of these semipolar (202¯1) GaN templates to produce high quality device structures is verified by the growth and characterization of InGaN/GaN multiple quantum well structures. It is expected that the methods shown here can enable the benefits of using semipolar orientations in a scalable and practical process and can be readily extended to achieve devices on surfaces using any orientation of semipolar GaN on sapphire.
Large scale Tesla coil guided discharges initiated by femtosecond laser filamentation in air
Authors: Arantchouk L. , Point G. , Brelet Y. , Prade B. , Carbonnel J. , André Y.-B. , Mysyrowicz A. , Houard A.
Published: July 2014

The guiding of meter scale electric discharges produced in air by a Tesla coil is realized in laboratory using a focused terawatt laser pulse undergoing filamentation. The influence of the focus position, the laser arrival time, or the gap length is studied to determine the best conditions for efficient laser guiding. Discharge parameters such as delay, jitter, and resistance are characterized. An increase of the discharge length by a factor 5 has been achieved with the laser filaments, corresponding to a mean breakdown field of 2 kV/cm for a 1.8 m gap length. Consecutive guided discharges at a repetition rate of 10 Hz are also reported.
On the limits of spin-exchange optical pumping of 3He
Authors: Chen W. C. , Gentile T. R. , Ye Q. , Walker T. G. , Babcock E.
Published: July 2014

We have obtained improvement in the 3He polarization achievable by spin-exchange optical pumping (SEOP). These results were primarily obtained in large neutron spin filter cells using diode bar lasers spectrally narrowed with chirped volume holographic gratings. As compared to our past results with lasers narrowed with diffraction gratings, we have observed between 5% and 11% fractional increase in the 3He polarization PHe. We also report a comparable improvement in PHe for two small cells, for which we would not have expected an increase from improved laser performance. In particular, prior extensive studies had indicated that the alkali-metal polarization was within 3% of unity in one of these cells. These results have impact on understanding the maximum PHe achievable by SEOP, whether the origin of the improvement is from increased alkali-metal polarization or decreased temperature-dependent relaxation. We conclude that the most likely explanation for the improvement in PHe is increased alkali-metal polarization. We have observed PHe of between 0.80 and 0.85 in several large cells, which marks a new precedent for the polarization achievable by SEOP.
Internal stress-induced melting below melting temperature at high-rate laser heating
Authors: Hwang Yong Seok , Levitas Valery I.
Published: July 2014

In this Letter, continuum thermodynamic and phase field approaches (PFAs) predicted internal stress-induced reduction in melting temperature for laser-irradiated heating of a nanolayer. Internal stresses appear due to thermal strain under constrained conditions and completely relax during melting, producing an additional thermodynamic driving force for melting. Thermodynamic melting temperature for Al reduces from 933.67 K for a stress-free condition down to 898.1 K for uniaxial strain and to 920.8 K for plane strain. Our PFA simulations demonstrated barrierless surface-induced melt nucleation below these temperatures and propagation of two solid-melt interfaces toward each other at the temperatures very close to the corresponding predicted thermodynamic equilibrium temperatures for the heating rate Q≤1.51×1010K/s. At higher heating rates, kinetic superheating competes with a reduction in melting temperature and melting under uniaxial strain occurs at 902.1 K for Q = 1.51 × 1011 K/s and 936.9 K for Q = 1.46 × 1012 K/s.
Time-dependent transport in amorphous semiconductors: Instability in the field-controlled regime
Authors: Buscemi Fabrizio , Piccinini Enrico , Brunetti Rossella , Rudan Massimo , Jacoboni Carlo
Published: July 2014

A time-dependent trap-limited conduction scheme is used to analyze the transient behavior of bistable homogeneous amorphous semiconductors when either the electric field or the current density is prescribed. Numerical outcomes confirm that, for a current-controlled system, the working point is unique and stable in any region of the current-voltage characteristic, while in a field-controlled system the negative differential-resistance region is unstable even in absence of circuit parasitics. The proposed theoretical approach represents a valid tool to grasp the relevant time-dependent features of the Ovonic switching in chalcogenide materials.
Imaging the p-n junction in a gallium nitride nanowire with a scanning microwave microscope
Authors: Imtiaz Atif , Wallis Thomas M. , Weber Joel C. , Coakley Kevin J. , Brubaker Matt D. , Blanchard Paul T. , Bertness Kris A. , Sanford Norman A. , Kabos Pavel
Published: July 2014

We used a broadband, atomic-force-microscope-based, scanning microwave microscope (SMM) to probe the axial dependence of the charge depletion in a p-n junction within a gallium nitride nanowire (NW). SMM enables the visualization of the p-n junction location without the need to make patterned electrical contacts to the NW. Spatially resolved measurements of S11′, which is the derivative of the RF reflection coefficient S11 with respect to voltage, varied strongly when probing axially along the NW and across the p-n junction. The axial variation in S11′  effectively mapped the asymmetric depletion arising from the doping concentrations on either side of the junction. Furthermore, variation of the probe tip voltage altered the apparent extent of features associated with the p-n junction in S11′ images.
Plasmon dispersions in high electron mobility terahertz detectors
Authors: Białek M. , Czapkiewicz M. , Wróbel J. , Umansky V. , Łusakowski J.
Published: July 2014

Low temperature, high magnetic field experiments were carried out with monochromatic terahertz (THz) sources to reveal multimode spectra of magnetoplasmons excited in gated and ungated samples processed on a high electron mobility GaAs/AlGaAs heterostructure. We show that playing with the geometry and thickness of the gate one can control both the plasmon dispersion relation and selection rules for plasmon excitation, giving a tool to a better control of plasmon resonances in THz detectors.
Enhancement of transition temperature in FexSe0.5Te0.5 film via iron vacancies
Authors: Zhuang J. C. , Yeoh W. K. , Cui X. Y. , Kim J. H. , Shi D. Q. , Shi Z. X. , Ringer S. P. , Wang X. L. , Dou S. X.
Published: July 2014

The effects of iron deficiency in FexSe0.5Te0.5 thin films (0.8 ≤ x ≤ 1) on superconductivity and electronic properties have been studied. A significant enhancement of the superconducting transition temperature (TC) up to 21 K was observed in the most Fe deficient film (x = 0.8). Based on the observed and simulated structural variation results, there is a high possibility that Fe vacancies can be formed in the FexSe0.5Te0.5 films. The enhancement of TC shows a strong relationship with the lattice strain effect induced by Fe vacancies. Importantly, the presence of Fe vacancies alters the charge carrier population by introducing electron charge carriers, with the Fe deficient film showing more metallic behavior than the defect-free film. Our study provides a means to enhance the superconductivity and tune the charge carriers via Fe vacancy, with no reliance on chemical doping.
Temperature-dependent energy storage properties of antiferroelectric Pb0.96La0.04Zr0.98Ti0.02O3 thin films
Authors: Hu Zhongqiang , Ma Beihai , Koritala R. E. , Balachandran Uthamalingam
Published: July 2014

The energy storage properties of antiferroelectric (AFE) Pb0.96La0.04Zr0.98Ti0.02O3 (PLZT 4/98/2) thin films were investigated as a function of temperature and applied electric field. The results indicated that recoverable energy density (Ure) and charge-discharge efficiency (η) of PLZT (4/98/2) depend weakly on temperature (from room temperature to 225 °C), while Ure increases linearly and η decreases exponentially with increasing electric field at room temperature. These findings are explained qualitatively on the basis of the kinetics of the temperature-induced transition of AFE-to-paraelectric phase and the field-induced transition of AFE-to-ferroelectric phase, respectively. The high Ure (≈61 J/cm3) and low leakage current density (≈3.5 × 10−8 and 3.5 × 10−5 A/cm2 at 25 and 225 °C, respectively) indicate that antiferroelectric PLZT (4/98/2) is a promising material for high-power energy storage.
Decoupled: Successful Planning Policies in Countries that Have Reduced per Capita Greenhouse Gas Emissions with Continued Economic Growth
Authors: Brinkley Catherine
Published: July 2014

This paper highlights planning interventions in countries that have implemented successful greenhouse gas (GHG) reduction policies while continuing to increase per capita GDP. Screening and reviewing all countries in the world, with this research I have identified nine countries that have steadily decoupled per capita carbon emissions from GDP. GHG emission profiles and pertinent policies from national case studies demonstrate the built environment sectors most responsive (waste, residential, land-use change, and forestry) and least responsive (transportation) to GHG reduction policies without import substitution. A comparison amongst case-study countries and theoretical models indicates the best opportunities for targeting GHG reductions.
Parents' views on human papillomavirus vaccination for sexually transmissible infection prevention: a qualitative study
Authors: Niccolai Linda M. , Hansen Caitlin E. , Credle Marisol , Ryan Sheryl A. , Shapiro Eugene D.
Published: July 2014

Background Human papillomavirus (HPV) is the most common sexually transmissible infection (STI) in the United States (US) and an important cause of several cancers. Vaccines that prevent HPV infections are now recommended for routine use in adolescents but coverage remains suboptimal in the US. Because they are often promoted as cancer prevention vaccines, little is known about parents’ views on vaccination for prevention of an STI. Methods: In this qualitative study, parents and caregivers of children ages 10–18 years completed an in-depth interview. Participants (n = 38) were recruited from an urban hospital-based primary care centre serving a low-income population in the north-eastern US during May 2013–February 2014. Interviews were transcribed and coded using a thematic content approach. Results: Five major themes emerged with relevance to the topic of HPV vaccination for STI prevention: (1) low awareness of HPV as an STI; (2) favourable opinions about STI prevention messages for vaccination, including at young ages; (3) salience of sexual mode of transmission, given the unpredictability of adolescent sexual behaviour and high rates of other STIs and teen pregnancy; (4) recognition that sexual health is a topic of conversation between adolescents and health care providers; and(5) relevance of personal experience. Conclusions: Discussing STI prevention in the context of HPV vaccination appears to be well accepted by urban, low-income minority families. In addition to providing information on cancer prevention, these messages may help to raise awareness, acceptability and uptake of HPV vaccines.