bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoluminescent chromium molybdate cluster coordinated with rare earth cations: synthesis, structure, optical and magnetic properties
Authors: Kumar Dinesh , Ahmad Shahab , Prakash G. Vijaya , Ramanujachary Kandalam V. , Ramanan Arunachalam
Published: June 2014

The photoluminescent chromium molybdate cluster is a potential molecular building block for synthesis of new solids with promising photophysical properties.
Computational electrochemistry: prediction of liquid-phase reduction potentials
Authors: Marenich Aleksandr V. , Ho Junming , Coote Michelle L. , Cramer Christopher J. , Truhlar Donald G.
Published: June 2014

The article reviews recent developments and applications for predicting the standard reduction potentials of chemical reactions in solution.
Ion-pair formation in aqueous strontium chloride and strontium hydroxide solutions under hydrothermal conditions by AC conductivity measurements
Authors: Arcis H. , Zimmerman G. H. , Tremaine P. R.
Published: June 2014

Stepwise ion pair formation constants for aqueous strontium chloride and strontium hydroxide have been determined fromT= 295 K toT= 625 K atp= 20 MPa, using a high-precision flow AC conductivity instrument.
Highly monodisperse multiple twinned AuCu–Pt trimetallic nanoparticles with high index surfaces
Authors: Khanal Subarna , Bhattarai Nabraj , McMaster David , Bahena Daniel , Velazquez-Salazar J. Jesus , Jose-Yacaman Miguel
Published: June 2014

Trimetallic nanoparticles possess different properties than their mono- and bi-metallic counterparts, opening a wide range of possibilities for diverse potential applications with the notion to study possible morphology, atomic ordering, reduce precious metal consumption and many others.
Complexation of trivalent americium and lanthanides with terdentate ‘N’ donor ligands: the role of rigidity in the ligand structure
Authors: Bhattacharyya Arunasis , Gadly Trilochan , Pathak Priyanath , Ghosh Sunil K. , Mohapatra Manoj , Ghanty Tapan K. , Mohapatra Prasanta K.
Published: June 2014

Americium and lanthanide complexation with Me2TBipy and Me2TPhen is studied by UV-Vis spectrophotometry, time resolved luminescence spectroscopy, single crystal XRD and DFT calculations.
Titanium incorporation into hematite photoelectrodes: theoretical considerations and experimental observations
Authors: Kronawitter C. X. , Zegkinoglou I. , Shen S.-H. , Liao P. , Cho I. S. , Zandi O. , Liu Y.-S. , Lashgari K. , Westin G. , Guo J.-H. , Himpsel F. J. , Carter E. A. , Zheng X. L. , Hamann T. W. , Koel B. E. , Mao S. S. , Vayssieres L.
Published: June 2014

A thorough literature review and the investigation by soft X-ray absorption spectroscopy at synchrotron facilities of Ti-Hematite photoelectrodes are provided.
A dopant-free hole-transporting material for efficient and stable perovskite solar cells
Authors: Liu Jian , Wu Yongzhen , Qin Chuanjiang , Yang Xudong , Yasuda Takeshi , Islam Ashraful , Zhang Kun , Peng Wenqin , Chen Wei , Han Liyuan
Published: June 2014

A tetrathiafulvalene derivative (TTF-1) was introduced into perovskite solar cells as a dopant-free hole-transporting material, yielding an efficiency over 11%.
Supramolecular control of organic p/n-heterojunctions by complementary hydrogen bonding
Authors: Black Hayden T. , Lin Huaping , Bélanger-Gariépy Francine , Perepichka Dmitrii F.
Published: June 2014

The supramolecular structure of organic semiconductors (OSCs) is the key parameter controlling their performance in organic electronic devices, and thus methods for controlling their self-assembly in the solid state are of the upmost importance. Recently, we have demonstrated the co-assembly of p- and n-type organic semiconductors through a three-point hydrogen-bonding interaction, utilizing an electron-rich dipyrrolopyridine (P2P) heterocycle which is complementary to naphthalenediimides (NDIs) both in its electronic structure and H bonding motif. The hydrogen-bonding-mediated co-assembly between P2P donor and NDI acceptor leads to ambipolar co-crystals and provides unique structural control over their solid-state packing characteristics. In this paper we expand our discussion on the crystal engineering aspects of H bonded donor–acceptor assemblies, reporting three new single co-crystal X-ray diffraction structures and analyzing the different packing characteristics that arise from the molecular structures employed. Particular attention is given toward understanding the formation of the two general motifs observed, segregated and mixed stacks. Co-assembly of the donor and acceptor components into a single, crystalline material, allows the creation of ambipolar semiconductors where the mutual arrangement of p- and n-conductive channels is engineered by supramolecular design based on complementary H bonding.
Integration of microfluidics into the synthetic biology design flow
Authors: Huang Haiyao , Densmore Douglas
Published: June 2014

Microfluidics may be used to address the challenges in synthetic biology workflow of specification–design–assembly–verification.
A biomimetic multicellular model of the airways using primary human cells
Authors: Sellgren Katelyn L. , Butala Elizabeth J. , Gilmour Brian P. , Randell Scott H. , Grego Sonia
Published: June 2014

A microfluidic model with three vertically stacked compartments separated by membranes was developed to mimic the human airway mucosa.
An iron stable isotope comparison between human erythrocytes and plasma
Authors: von Blanckenburg Friedhelm , Oelze Marcus , Schmid Dietmar G. , van Zuilen Kirsten , Gschwind Hans-Peter , Slade Alan J. , Stitah Sylvie , Kaufmann Daniel , Swart Piet
Published: June 2014

Iron stable isotopes can be measured precisely by multicollector ICP-MS. We explore whether the isotope ratios fractionate between human erythrocytes and human blood plasma.
Synthesis of novel benzimidazole-carbazole-N-glycosylamines and their self-assembly into nanofibers
Authors: Dhinakaran Manivannan Kalavathi , Soundarajan Kamalakannan , Mohan Das Thangamuthu
Published: June 2014

A new class of benzimidazole-carbazole-N-glycosylamines were synthesized and self-assembled through non-covalent interaction into mechanically and thermally stable organogels with nanofibrous morphology.
Facile synthesis and morphogenesis of superparamagnetic iron oxide nanoparticles for high-performance supercapacitor applications
Authors: Mitchell Elias , Gupta Ram K. , Mensah-Darkwa Kwadwo , Kumar Dhananjay , Ramasamy Karthik , Gupta Bipin K. , Kahol Pawan
Published: June 2014

The TEM image of the synthesized iron oxide nanocrystals.
Breaking the dichotomy of reactivity vs. chemoselectivity in catalytic SN1 reactions of alcohols
Authors: Hellal Malik , Falk Florian C. , Wolf Eléna , Dryzhakov Marian , Moran Joseph
Published: June 2014

B(C6F5)3 possesses a different reactivity/chemoselectivity profile than traditional Lewis and Brønsted acids and is effective at enabling catalytic SN1 reactions of alcohols in the presence of acid sensitive groups without compromising reaction rates, substrate scope or catalyst loadings.
Copper-mediated C(sp2)–H amination using TMSN3as a nitrogen source: redox-neutral access to primary anilines
Authors: Peng Jiangling , Chen Ming , Xie Zeqiang , Luo Shuang , Zhu Qiang
Published: June 2014

A Cu-mediated C–H amination for the preparation of primary anilines under redox neutral conditions is developed.
Degradation of acenaphthylene and anthracene by chemically modified laccase from Trametes versicolor
Authors: Liu Yulong , Hua Xiufu
Published: June 2014

We are studying the chemically modified laccase from Trametes versicolor for use in the in vitro oxidation of two polycyclic aromatic hydrocarbons (PAHs), acenaphthylene and anthracene, in combination with 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as a redox mediator.
Strong antiferromagnetic interaction in a 3D copper–organic framework and spin-glass-like behaviour in a 1D nickel compound
Authors: Liao Sheng-Yun , Li Tian-Hao , Tian Jin-Lei , Yang Lin-Yan , Gu Wen , Liu Xin
Published: June 2014

Novel 3D frameworks containing D4h paddle-wheel copper units and 1D zigzag nickel chain have been successfully synthesized and characterized magnetically.
A perfluorohexyl containing diketopyrrolopyrrole (DPP) small molecule for high performance ambipolar transistors with balanced hole and electron mobilites
Authors: Wang Yuanyuan , Huang Qiuliu , Liu Zhiqiang , Li Hongxiang
Published: June 2014

Diketopyrrolopyrrole (DPP) small molecules DPPTT-F and DPPTT-H were synthesized. DPPTT-F displayed ambipolar characteristics with balanced hole and electron mobilities in air.
Modulation of structural, energetic and electronic properties of DNA and size-expanded DNA bases upon binding to gold clusters
Authors: Rai Sandhya , Ranjan Supriya , Singh Harjinder , Priyakumar U. Deva
Published: June 2014

A strong modulation in electronic properties, indicating that such complexes have the potential to serve as scaffolds for building nano electronic devices.
Mechanistic insights into l-proline-catalyzed transamidation of carboxamide with benzylamine from density functional theory calculations
Authors: Yang Xin , Fan Linlin , Xue Ying
Published: June 2014

Density functional theory was used to study mechanism of transamidation of carboxamides with amines catalysed by l-proline in three different solvents.
Controlled synthesis of porous Co3O4–C hybrid nanosheet arrays and their application in lithium ion batteries
Authors: Wang Jun , Gao Bing , Zhang Long , Li Rui , Shen Jinpeng , Qiao Zhiqiang , Yang Guangcheng , Nie Fude
Published: June 2014

Two-dimensional Co3O4 nanostructures with porous architectures are experiencing rapid development in functional material fields for their unique structures and properties.
Air-based photoelectrochemical cell capturing water molecules from ambient air for hydrogen production
Authors: Rongé J. , Deng S. , Pulinthanathu Sree S. , Bosserez T. , Verbruggen S. W. , Kumar Singh N. , Dendooven J. , Roeffaers M. B. J. , Taulelle F. , De Volder M. , Detavernier C. , Martens J. A.
Published: June 2014

A system is demonstrated that autonomously produces hydrogen gas using sunlight and outside air as the only inputs.
Improving students' argumentation skills through a product life-cycle analysis project in chemistry education
Authors: Juntunen M. K. , Aksela M. K.
Published: June 2014

The aim of the study discussed in this paper was to link existing research about the argumentation skills of students to the teaching of life-cycle analysis (LCA) in order to promote an evidence-based approach to the teaching of and learning about materials used in consumer products. This case-study is part of a larger design research project that focuses on improving education for sustainable development (ESD) in chemistry teaching by means of combining a socio-scientific issue (SSI) and life-cycle analysis with inquiry-based learning. The research question was: How do students (N= 8) use scientific, ecological, socio-economical and ethical argumentation in the life-cycle analysis of a product? The research method for this study was content analysis performed on written student answers and an audio recording of a debate. The results show that the students' scientific and ecological argumentation skills with regard to the life-cycles of products were improved during the life-cycle analysis project. The studying also affected, to a lesser extent, the students' ability to form socio-economical and ethical arguments. The type of student-centred and cross-curricular product life-cycle analysis project discussed in this paper is a suitable new method for teaching socio-scientific argumentation to chemistry students at the secondary school level.
Surface dynamics of poly(methyl methacrylate) films affected by the concentration of casting solutions
Authors: Tian Houkuan , Yang Yuhui , Ding Jia , Liu Wanglong , Zuo Biao , Yang Juping , Wang Xinping
Published: June 2014

Suppressed surface dynamics of poly(methyl methacrylate) chains on the surface of spin-coated films prepared from concentrated casting solutions.
Aggregation and segregation of confined active particles
Authors: Yang Xingbo , Manning M. Lisa , Marchetti M. Cristina
Published: June 2014

Our work demonstrates the first step towards understanding the equation of state of active systems at high density.
In situ investigation of halide co-ion effects on SDS adsorption at air–water interfaces
Authors: Nguyen Khoi Tan , Nguyen Anh V.
Published: June 2014

Halide co-ions are shown to strongly influence adsorption of anionic surfactant SDS unexpectedly.
Highly sensitive SnO2 nanofiber chemiresistors with a low optimal operating temperature: synergistic effect of Cu2+/Au co-doping
Authors: Li Zhenyu , Wang Xungai , Lin Tong
Published: June 2014

SnO2 nanofibers after being co-doped with Cu2+ and Au show considerably enhanced sensing performances at an unexpectedly decreased operating temperature and a synergistic effect occurs when the two dopants are introduced together.
Electrochemical behavior and surface structural change of LiMn2O4charged to 5.1 V
Authors: Tang Daichun , Ben Liubin , Sun Yang , Chen Bin , Yang Zhenzhong , Gu Lin , Huang Xuejie
Published: June 2014

Charging a spinel LiMn2O4cathode material to high voltage (>4.3 V) is a convenient way to obtain more lithium ions for formation of an anodic solid-electrolyte-interface in a full cell.
High capacity silicon nitride-based composite anodes for lithium ion batteries
Authors: de Guzman Rhet C. , Yang Jinho , Ming-Cheng Cheng Mark , Salley Steven O. , Ng K. Y. Simon
Published: June 2014

A CVD-synthesized SiNx LIB anode material exhibits stable, high capacity performance via two stage electrochemical reactions (conversion and then alloying).
Quantum-chemical study of stable, meta-stable and high-pressure alumina polymorphs and aluminum hydroxides
Authors: Peintinger Michael F. , Kratz Michael J. , Bredow Thomas
Published: June 2014

The structure, properties and stability of 7 thermodynamically stable, meta-stable and high-pressure Al2O3 polymorphs and the structure and relative stability of 4 Al hydroxides were calculated with periodic hybrid density functional theory and compared with available experimental data.
Directly coat TiO2 on hydrophobic NaYF4:Yb,Tm nanoplates and regulate their photocatalytic activities with the core size
Authors: Su Wankui , Zheng Mengmeng , Li Lei , Wang Kun , Qiao Ru , Zhong Yijun , Hu Yong , Li Zhengquan
Published: June 2014

Small NaYF4:Yb,Tm@TiO2 nanophotocatalysts that work under both near-infrared and ultraviolet lights were developed.
Sustainable photocatalytic production of hydrogen peroxide from water and molecular oxygen
Authors: Kaynan Niv , Berke Binyamin Adler , Hazut Ori , Yerushalmi Roie
Published: June 2014

Direct photocatalytic production of H2O2 is demonstrated using a heterogeneous catalyst made from environmentally compatible materials and light energy without the need for additional chemical energy (sacrificial compounds) or applied electrical potential. Fine-tuning of catalyst architecture and interface design enables exceptional photocatalytic activity.
Electron transport in crystalline PCBM-like fullerene derivatives: a comparative computational study
Authors: Idé Julien , Fazzi Daniele , Casalegno Mosé , Meille Stefano Valdo , Raos Guido
Published: June 2014

We present a computational analysis of electron transport within several crystalline fullerene derivatives. Different polymorphs are characterized by one-, two- or three-dimensional charge transport networks.
Loop‐analysis‐based continuation power flow algorithm for distribution networks
Authors: Ju Yuntao , Wu Wenchuan , Zhang Boming , Sun Hongbin
Published: June 2014

A new continuation power flow method is proposed, which is an extension of the popular backward/forward sweep power flow (BFS) for distribution network. The different reasons for the divergence of Newton's algorithm and fixed‐point iteration algorithm near the saddle node bifurcation point have been investigated extensively. Loop‐analysis‐based power flow (LBPF) is a revised version of BFS, which belong to fixed‐point iteration algorithm and its convergence remains satisfactory in a meshed network. Based on LBPF, a tailored continuous power flow method is developed, which can be used as a voltage stability analysis tool for both radial and meshed distribution networks. Numerical test results are presented to validate the proposed procedure.
Multi‐objective stochastic optimal planning method for stand‐alone microgrid system
Authors: Guo Li , Liu Wenjian , Jiao Bingqi , Hong Bowen , Wang Chengshan
Published: June 2014

To achieve economic and environmental benefit for the stand‐alone microgrid consisting of diesel generators, wind turbine generators, photovoltaic generation system and lead‐acid batteries, a multi‐objective stochastic optimal planning method and a stochastic chance‐constrained programming model are presented. In the model, the optimal objective is to simultaneously minimise the total net present cost and carbon dioxide emission in life cycle; the type and capacity of distributed generation units have been selected as the optimal variables; the loss of capacity is adopted as probability index constraint; the coordinated operation strategies between diesel generators and battery, the multi‐unit operation constraints of diesel generators and the reserve capacity have been considered in the hard‐circle operation strategy. Considering the uncertainties of wind speed, clearness index and load demand, Markov process transition probability matrix is adopted to synthesise those time series data. Optimal planning for an island microgrid system has been carried out by the planning system for microgrid (PSMG), a self‐developed optimal planning software based on the multi‐objective stochastic optimal planning method for stand‐alone microgrid system.
Zero‐current switching series loaded resonant converter insensitive to resonant component tolerance for battery charger
Authors: Park Junsung , Kim Minjae , Choi Sewan
Published: June 2014

This study proposes an electric vehicle (EV) battery charger with a fixed frequency zero‐current‐switching (ZCS) series loaded resonant converter (SRC). Owing to the proposed fixed frequency operation the SRC is capable of operating under ZCS turn on and turn off regardless of voltage variation or load variation, and the magnetic components and the electromagnetic interference (EMI) filters can be optimised. The proposed battery charger has minimum component count, which makes it possible to achieve low cost and high reliability. Also, it is insensitive to resonant component tolerances and therefore suitable for high volume manufacturing. Experimental results are provided from a 3.3 kW prototype which was built for 2011 Future Energy Challenge Competition.
Amplitude scintillation effects on SAR
Authors: Belcher David P. , Cannon Paul S.
Published: June 2014

Space‐based low‐frequency synthetic aperture radar (SAR) is affected by the ionosphere, which induces both phase and amplitude fluctuations, known as scintillation, into the radar signal. This paper describes the effect of amplitude scintillation on SAR imagery. The two‐way amplitude and intensity probability density functions (pdf) for both monostatic and bistatic SAR are derived from the one‐way Nakagami‐m distribution. The moments are then used to determine the SAR radiometric calibration error and image contrast from the one‐way S4 index. It is also shown that monostatic SAR experiences an S4‐dependent radar cross‐section (RCS) enhancement that is not experienced by bistatic SAR. The anisotropy of the ionospheric irregularities strongly affects the degree to which amplitude scintillation will be visible in SAR imagery. The description of anisotropic effects is reviewed and extended to cover SAR. The variation over the Earth is illustrated, showing that a sun‐synchronous satellite will experience the strongest effect near Brazil. Two PALSAR images of the same area of Brazilian rainforest are compared, one of which shows azimuthal streaking, corresponding to an amplitude modulation of ± 1 dB. The one‐way S4 index is determined from this imagery using both the RCS enhancement and image contrast measures of S4, which produce similar results.
Unitary reduced‐dimensional estimation of signal parameters via rotational invariance techniques for angle estimation in monostatic multiple‐input–multiple‐output radar with rectangular arrays
Authors: Li Jianfeng , Zhang Xiaofei
Published: June 2014

In this study, the issue of two‐dimensional direction of arrival estimation in monostatic multiple‐input–multiple‐output (MIMO) radar with rectangular arrays is studied and an algorithm based on estimation of signal parameters via rotational invariance techniques (ESPRIT) is proposed. Through the reduced‐dimensional transformation and unitary transformation, the proposed algorithm has very low complexity because of the low‐dimension and real‐valued computations. Meanwhile, the angle estimation performance of the proposed algorithm is improved compared with conventional ESPRIT and Unitary ESPRIT. The real‐valued rotational invariance is utilised to achieve automatically paired estimations of the azimuth and elevation angles in monostatic MIMO radar. Error analysis of the angle estimation and Cramér‐Rao bound in MIMO radar are derived. Simulation results verify the improvement and usefulness of our algorithm.
Short‐range ground moving target indication in forward looking airborne radar based on elevation prefiltering
Authors: Wen Cai , Wang Tong , Wu Jianxin
Published: June 2014

Clutter suppression for short‐range ground moving target indication in forward looking airborne radar is a challenging problem because of the range‐dependent clutter. If the pulse repetition frequency is chosen so high that radar clutter is range ambiguous, then additional blind velocities at short‐range induced by far‐range clutter will occur. To eliminate these additional blind velocities, an efficient beamspace‐based adaptive prefiltering method in elevation is proposed in this study to suppress ambiguous far‐range clutter. The proposed beamformer can provide nearly optimal adapted elevation pattern because of the improved training data selection strategy. After eliminating the impact of ambiguous far‐range clutter, the Doppler‐compensation‐based space–time adaptive processing method could be carried out to suppress residual range‐dependent short‐range clutter. In addition, the proposed prefiltering method is computationally efficient, and hence it is suitable for engineering application.
Parameter estimation for Pareto and K distributed clutter with noise
Authors: Bocquet Stephen
Published: June 2014

The form of the z log z estimator is derived for both Pareto and K distributed clutter plus noise. When noise is included, numerical zero finding is required to obtain the shape parameter from the estimator, but it still provides a robust and accurate method that is relatively quick to compute. It is compared with two other methods. The method of moments is the simplest and fastest to compute, but less accurate than other methods if the clutter shape parameter is small. A constrained maximum‐likelihood (ML) estimator is constructed by maximising the log likelihood function in one dimension to find the shape parameter, while holding the mean power and clutter to noise ratio constant. This estimator is robust and accurate, but relatively slow because numerical integration is required to calculate the likelihood function, along with numerical optimisation to find the maximum. If the noise power is unknown, it can be obtained using the first two intensity moments in combination with either the constrained ML or z log z estimator. These combinations provide more robust and accurate estimates than the third intensity moment.
Managing Knowledge and Managing Knowledge Work: What we know and what the Future holds
Authors: Newell Sue
Published: June 2014

In this paper we review the recent IS literature on knowledge and consider different assumptions that underpin different approaches to this broad research area. In doing this we contrast those who focus on knowledge management with those who focus on knowing as practice and examine how contexts, processes and purposes need to be considered whichever approach to knowledge one is adopting. We also identify how recent IT developments, especially in relation to social software and the digitization of everything, are presenting new opportunities (and challenges) for how organizations can manage both knowledge and knowledge work. This presents IS scholars with new research agendas for examining and understanding the relationships between technology, organization and society.
Determinants of Vendor Profitability in Two Contractual Regimes: An Empirical Analysis of Enterprise Resource Planning Projects
Authors: Hoermann Stefan , Hlavka Tobias , Schermann Michael , Krcmar Helmut
Published: June 2014

In this paper, we investigate the effects of four determinants of vendor profitability in enterprise resource planning (ERP) outsourcing projects under two contractual regimes: fixed price (FP) contracts and time and material (TM) contracts. We hypothesize that effect sizes are larger under FP contracts than under TM contracts. From a transaction cost economics perspective, we hypothesize that project uncertainty and project size are negatively associated with vendor profitability. From a knowledge-based view of the firm perspective, we hypothesize that industry knowledge and client knowledge are positively associated with vendor profitability. We tested these hypotheses on a comprehensive archival data set comprising 33,908 projects from a major vendor in the ERP software market. Our results confirm and extend previous research. Our results support the existence of two contractual regimes: effect sizes on vendor profitability are indeed much larger in FP contracts than in TM contracts. Also in line with prior research, our results suggest negative effects of project uncertainty and project size in terms of project budget on vendor profitability and positive effects of industry knowledge on vendor profitability. Contrary to prior knowledge, we find that project size in terms of project duration is significantly positively associated with vendor profitability in FP contracts. Also contrary to what is known, we find a significant negative effect of client knowledge on vendor profitability in both contractual regimes.
A boron nitride nanotube peapod thermal rectifier
Authors: Loh G. C. , Baillargeat D.
Published: June 2014

The precise guidance of heat from one specific location to another is paramount in many industrial and commercial applications, including thermal management and thermoelectric generation. One of the cardinal requirements is a preferential conduction of thermal energy, also known as thermal rectification, in the materials. This study introduces a novel nanomaterial for rectifying heat—the boron nitride nanotube peapod thermal rectifier. Classical non-equilibrium molecular dynamics simulations are performed on this nanomaterial, and interestingly, the strength of the rectification phenomenon is dissimilar at different operating temperatures. This is due to the contingence of the thermal flux on the conductance at the localized region around the scatterer, which varies with temperature. The rectification performance of the peapod rectifier is inherently dependent on its asymmetry. Last but not least, the favourable rectifying direction in the nanomaterial is established.
Effects on calculated half-widths and shifts from the line coupling for asymmetric-top molecules
Authors: Ma Q. , Boulet C. , Tipping R. H.
Published: June 2014

The refinement of the Robert-Bonamy formalism by considering the line coupling for linear molecules developed in our previous studies [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013); 140, 104304 (2014)] have been extended to asymmetric-top molecules. For H2O immersed in N2 bath, the line coupling selection rules applicable for the pure rotational band to determine whether two specified lines are coupled or not are established. Meanwhile, because the coupling strengths are determined by relative importance of off-diagonal matrix elements versus diagonal elements of the operator −iS1 − S2, quantitative tools are developed with which one is able to remove weakly coupled lines from consideration. By applying these tools, we have found that within reasonable tolerances, most of the H2O lines in the pure rotational band are not coupled. This reflects the fact that differences of energy levels of the H2O states are pretty large. But, there are several dozen strongly coupled lines and they can be categorized into different groups such that the line couplings occur only within the same groups. In practice, to identify those strongly coupled lines and to confine them into sub-linespaces are crucial steps in considering the line coupling. We have calculated half-widths and shifts for some groups, including the line coupling. Based on these calculations, one can conclude that for most of the H2O lines, it is unnecessary to consider the line coupling. However, for several dozens of lines, effects on the calculated half-widths from the line coupling are small, but remain noticeable and reductions of calculated half-widths due to including the line coupling could reach to 5%. Meanwhile, effects on the calculated shifts are very significant and variations of calculated shifts could be as large as 25%.
Nonlinear development and secondary instability of traveling crossflow vortices
Authors: Li Fei , Choudhari Meelan M. , Duan Lian , Chang Chau-Lyan
Published: June 2014

Building upon the prior research targeting the laminar breakdown mechanisms associated with stationary crossflow instability over a swept-wing configuration, this paper investigates the secondary instability of traveling crossflow modes as an alternate scenario for transition. For the parameter range investigated herein, this alternate scenario is shown to be viable unless the initial amplitudes of the traveling crossflow instability are lower than those of the stationary modes by considerably more than one order of magnitude. The linear growth predictions based on the secondary instability theory are found to agree well with both parabolized stability equations and direct numerical simulation, and the most significant discrepancies among the various predictions are limited to spatial regions of relatively weak secondary growth, i.e., regions where the primary disturbance amplitudes are smaller in comparison to their peak values. Nonlinear effects on secondary instability evolution are also investigated and found to be initially stabilizing when they first come into play.
Fast electron spin resonance controlled manipulation of spin injection into quantum dots
Authors: Merz Andreas , Siller Jan , Schittny Robert , Krämmer Christoph , Kalt Heinz , Hetterich Michael
Published: June 2014

In our spin-injection light-emitting diodes, electrons are spin-polarized in a semimagnetic ZnMnSe spin aligner and then injected into InGaAs quantum dots. The resulting electron spin state can be read out by measuring the circular polarization state of the emitted light. Here, we resonantly excite the Mn 3d electron spin system with microwave pulses and perform time-resolved measurements of the spin dynamics. We find that we are able to control the spin polarization of the injected electrons on a microsecond timescale. This electron spin resonance induced spin control could be one of the ingredients required to utilize the quantum dot electrons or the Mn spins as qubits.
Prestrain relaxation in non-covalently modified ethylene-vinyl acetate | PyChol | multiwall carbon nanotube nanocomposites
Authors: Winter A. D. , Jaye C. , Fischer D. , Omastová M. , Campo E. M.
Published: June 2014

Effects of aging on chemical structure and molecular dynamic behaviour of strained thermally active ethylene-vinyl acetate | multiwall carbon nanotube (EVA|MWCNT) composites were investigated by spectroscopy and microscopy techniques. Aged composites showed spatial inhomogeneity due to system relaxation. Inhomogeneity is attributed to segregation of non-covalently linked cholestryl 1-pyrenecarboxylate, acting as MWCNT dispersant and polymer compatibilizer. Analysis of molecular interplay between filler and matrix upon in situ temperature variation showed a lack of synchronicity, which had been observed in fresh composites. Reduced synchronous interplay allowed quantification of degraded π-π interactions, promoting PyChol unlatching as a result of both sonication and strained-derived π-π degradation.
Possible central extensions of non-relativistic conformal algebras in 1+1
Authors: Hosseiny Ali
Published: June 2014

We investigate possibility of central extension for non-relativistic conformal algebras in 1+1 dimension. Three different forms of charges can be suggested. A trivial charge for temporal part of the algebra exists for all elements of l-Galilei algebra class. In attempt to find a central extension as of conformal Galilean algebra for other elements of the l-Galilei class, possibility for such extension was excluded. For integer and half integer elements of the class, we can have an infinite extension of the generalized mass charge for the Virasoro-like extended algebra. For finite algebras, a regular charge inspired by Schrödinger central extension is possible.
Network analysis of proton transfer in liquid water
Authors: Shevchuk Roman , Agmon Noam , Rao Francesco
Published: June 2014

Proton transfer in macromolecular systems is a fascinating yet elusive process. In the last ten years, molecular simulations have shown to be a useful tool to unveil the atomistic mechanism. Notwithstanding, the large number of degrees of freedom involved make the accurate description of the process very hard even for the case of proton diffusion in bulk water. Here, multi-state empirical valence bond molecular dynamics simulations in conjunction with complex network analysis are applied to study proton transfer in liquid water. Making use of a transition network formalism, this approach takes into account the time evolution of several coordinates simultaneously. Our results provide evidence for a strong dependence of proton transfer on the length of the hydrogen bond solvating the Zundel complex, with proton transfer enhancement as shorter bonds are formed at the acceptor site. We identify six major states (nodes) on the network leading from the “special pair” to a more symmetric Zundel complex required for transferring the proton. Moreover, the second solvation shell specifically rearranges to promote the transfer, reiterating the idea that solvation beyond the first shell of the Zundel complex plays a crucial role in the process.
Understanding the presence of vacancy clusters in ZnO from a kinetic perspective
Authors: Bang Junhyeok , Kim Youg-Sung , Park C. H. , Gao F. , Zhang S. B.
Published: June 2014

Vacancy clusters have been observed in ZnO by positron-annihilation spectroscopy (PAS), but detailed mechanisms are unclear. This is because the clustering happens in non-equilibrium conditions, for which theoretical method has not been well established. Combining first-principles calculation and kinetic Monte Carlo simulation, we determine the roles of non-equilibrium kinetics on the vacancies clustering. We find that clustering starts with the formation of Zn and O vacancy pairs (VZn − Vo), which further grow by attracting additional mono-vacancies. At this stage, vacancy diffusivity becomes crucial: due to the larger diffusivity of VZn compared to VO, more VZn-abundant clusters are formed than VO-abundant clusters. The large dissociation energy barriers, e.g., over 2.5 eV for (VZn − Vo), suggest that, once formed, it is difficult for the clusters to dissociate. By promoting mono-vacancy diffusion, thermal annealing will increase the size of the clusters. As the PAS is insensitive to VO donor defects, our results suggest an interpretation of the experimental data that could not have been made without the in-depth calculations.
Shear-horizontal surface acoustic wave phononic device with high density filling material for ultra-low power sensing applications
Authors: Richardson M. , Sankaranarayanan S. K. R. S. , Bhethanabotla V. R.
Published: June 2014

Finite element simulations of a phononic shear-horizontal surface acoustic wave (SAW) sensor based on ST 90°-X Quartz reveal a dramatic reduction in power consumption. The phononic sensor is realized by artificially structuring the delay path to form an acoustic meta-material comprised of a periodic microcavity array incorporating high-density materials such as tantalum or tungsten. Constructive interference of the scattered and secondary reflected waves at every microcavity interface leads to acoustic energy confinement in the high-density regions translating into reduced power loss. Tantalum filled cavities show the best performance while tungsten inclusions create a phononic bandgap. Based on our simulation results, SAW devices with tantalum filled microcavities were fabricated and shown to significantly decrease insertion loss. Our findings offer encouraging prospects for designing low power, highly sensitive portable biosensors.
Experimental observation of acoustic sub-harmonic diffraction by a grating
Authors: Liu Jingfei , Declercq Nico F.
Published: June 2014

A diffraction grating is a spatial filter causing sound waves or optical waves to reflect in directions determined by the frequency of the waves and the period of the grating. The classical grating equation is the governing principle that has successfully described the diffraction phenomena caused by gratings. However, in this work, we show experimental observation of the so-called sub-harmonic diffraction in acoustics that cannot be explained by the classical grating equation. Experiments indicate two physical phenomena causing the effect: internal scattering effects within the corrugation causing a phase shift and nonlinear acoustic effects generating new frequencies. This discovery expands our current understanding of the diffraction phenomenon, and it also makes it possible to better design spatial diffraction spectra, such as a rainbow effect in optics with a more complicated color spectrum than a traditional rainbow. The discovery reveals also a possibly new technique to study nonlinear acoustics by exploitation of the natural spatial filtering effect inherent to an acoustic diffraction grating.
Control carrier recombination of multi-scale textured black silicon surface for high performance solar cells
Authors: Hong M. , Yuan G. D. , Peng Y. , Chen H. Y. , Zhang Y. , Liu Z. Q. , Wang J. X. , Cai B. , Zhu Y. M. , Chen Y. , Liu J. H. , Li J. M.
Published: June 2014

We report an enhanced performance of multi-scale textured black silicon solar cell with power conversion efficiency of 15.5% by using anisotropic tetramethylammonium hydroxide etching to control the recombination. The multi-scale texture can effectively reduce the surface reflectance in a wide wavelength range, and both the surface and Auger recombination can be effectively suppressed by etching the samples after the n++ emitter formed. Our result shows that the reformed solar cell has higher conversion efficiency than that of conventional pyramid textured cell (15.3%). This work presents an effective method for improving the performance of nanostructured silicon solar cells.
High performance photodiodes based on InAs/InAsSb type-II superlattices for very long wavelength infrared detection
Authors: Hoang A. M. , Chen G. , Chevallier R. , Haddadi A. , Razeghi M.
Published: June 2014

Very long wavelength infrared photodetectors based on InAs/InAsSb type-II superlattices are demonstrated on GaSb substrate. A heterostructure photodiode was grown with 50% cut-off wavelength of 14.6 μm. At 77 K, the photodiode exhibited a peak responsivity of 4.8 A/W, corresponding to a quantum efficiency of 46% at −300 mV bias voltage from front side illumination without antireflective coating. With the dark current density of 0.7 A/cm2, it provided a specific detectivity of 1.4 × 1010 Jones. The device performance was investigated as a function of operating temperature, revealing a very stable optical response and a background limited performance below 50 K.
Modeling of transport phenomena in tokamak plasmas with neural networks
Authors: Meneghini O. , Luna C. J. , Smith S. P. , Lao L. L.
Published: June 2014

A new transport model that uses neural networks (NNs) to yield electron and ion heat flux profiles has been developed. Given a set of local dimensionless plasma parameters similar to the ones that the highest fidelity models use, the NN model is able to efficiently and accurately predict the ion and electron heat transport profiles. As a benchmark, a NN was built, trained, and tested on data from the 2012 and 2013 DIII-D experimental campaigns. It is found that NN can capture the experimental behavior over the majority of the plasma radius and across a broad range of plasma regimes. Although each radial location is calculated independently from the others, the heat flux profiles are smooth, suggesting that the solution found by the NN is a smooth function of the local input parameters. This result supports the evidence of a well-defined, non-stochastic relationship between the input parameters and the experimentally measured transport fluxes. The numerical efficiency of this method, requiring only a few CPU-μs per data point, makes it ideal for scenario development simulations and real-time plasma control.
Ultrabroad stimulated emission from quantum well laser
Authors: Wang Huolei , Zhou Xuliang , Yu Hongyan , Mi Junping , Wang Jiaqi , Bian Jing , Ding Ying , Chen Weixi , Wang Wei , Pan Jiaoqing
Published: June 2014

Observation of ultrabroad stimulated emission from a simplex quantum well based laser at the center wavelength of 1.06 μm is reported. With increased injection current, spectrum as broad as 38 nm and a pulsed output power of ∼50 mW have been measured. The experiments show evidence of an unexplored broad emission regime in the InGaAs/GaAs quantum well material system, which still needs theoretical modeling and further analysis.
Gliding performance in the yellow-bellied glider in low-canopy forest
Authors: Goldingay Ross L.
Published: June 2014

Knowledge of the gliding performance of gliding mammals is fundamental to understanding how these species have adapted to their environment and is of increasing relevance to their conservation. I describe aspects of the glide performance of the yellow-bellied glider (Petaurus australis) based on 22 glides of 17 individuals within 20–30-m-high open forest in western Victoria. Gliders launched into a glide from a horizontal branch that was, on average, 2.8 m below the top of a tree, 5.2 m out from the main trunk and 18.5 m above the ground. Gliders landed on the trunks of trees 5.8 m above the ground. The mean horizontal glide distance was 25.2 ± 1.5 m (s.e.) (range = 19–45 m), producing a glide ratio (horizontal distance/height dropped) of 2.0 and a glide angle of 27.3°. These values are similar to those reported for other gliding petaurids in low-canopy forest. This knowledge should be used to guide the management of habitat connectivity for yellow-bellied gliders.
Toxicity of cerium oxide nanoparticles to the earthworm Eisenia fetida: subtle effects
Authors: Lahive Elma , Jurkschat Kerstin , Shaw Benjamin J. , Handy Richard D. , Spurgeon David J. , Svendsen Claus
Published: June 2014

Environmental context This study investigates the toxicity of cerium oxide nanoparticles to earthworms, key organisms in soil ecosystems. Cerium oxide did not affect survival or reproduction of the earthworms but did exert histological changes. We conclude that current soil guidelines, based simply on metal toxicity, appear to adequately protect against cerium exposure risk, at least for earthworms. Abstract The toxicity of cerium oxide (CeO2) nanoparticles (NPs) in soils is largely unknown. This study aimed to investigate the toxicity of three different CeO2 NPs to the earthworm, Eisenia fetida, for effects on survival (at day 28) and reproduction (at day 56), as well as bioaccumulation and histopathological effects. Eisenia fetida were exposed in standard Lufa 2.2 soil to three CeO2 NPs of different size ranges (5–80nm), one larger particle (300nm) and a cerium salt (ammonium cerium nitrate) over an exposure range from 41–10000mgCekg–1. Survival and reproduction were not affected by the four CeO2 particles, even at the highest exposure concentration tested. Alternatively, 10000mgCekg–1 cerium salt affected survival and reproduction; Median lethal concentration (LC50) and effective concentration (EC50) values were 317.8 and 294.6mgCekg–1. Despite a lack of toxic effect from the different forms of CeO2 particles, there was a dose-dependent increase in cerium in the organisms at all exposure concentrations, and for all material types. Earthworms exposed to CeO2 particles had higher concentrations of total cerium compared to those exposed to ionic cerium, but without exhibiting the same toxic effect. Histological observations in earthworms exposed to the particulate forms of CeO2 did, however, show cuticle loss from the body wall and some loss of gut epithelium integrity. The data suggest that that CeO2 NPs do not affect survival or reproduction in E. fetida over the standard test period. However, there were histological changes that could indicate possible deleterious effects over longer-term exposures.
β2-Adrenergic receptor agonist ameliorates phenotypes and corrects microRNA-mediated IGF1 deficits in a mouse model of Rett syndrome
Authors: Mellios Nikolaos , Woodson Jonathan , Garcia Rodrigo I. , Crawford Benjamin , Sharma Jitendra , Sheridan Steven D. , Haggarty Stephen J. , Sur Mriganka
Published: June 2014

Significance

Rett syndrome is a devastating neurodevelopmental disorder with diverse symptoms and no available treatment. Previous work from our laboratory has identified deficits in insulin-like growth factor 1 (IGF1) levels in
Mecp2
mutant mice, and demonstrated correction of symptoms and molecular-signaling alterations with IGF1 treatment. Here, we show that treatment with the adrenergic receptor agonist clenbuterol rescues a microRNA pathway that underlies IGF1 expression, improves survival, and ameliorates diverse phenotypes in
Mecp2
mutant mice. Life span measurements suggest that cotreatment with clenbuterol and IGF1 may further enhance their therapeutic effects in the mouse model of the disease. We would like to strongly caution, however, against any use of clenbuterol before clinical trials establish its safety and efficacy in Rett syndrome.
Nonlinear permanent migration response to climatic variations but minimal response to disasters
Authors: Bohra-Mishra Pratikshya , Oppenheimer Michael , Hsiang Solomon M.
Published: June 2014

Significance

In the context of global climate change and increasing impact of some types of natural disasters, there has been significant interest in investigating the influence of climatic factors on human migration. We explore a more comprehensive set of climatic factors than used in most previous work to predict the effects of sudden natural disasters and climatic variations on migration. By following province-to-province movement of more than 7,000 households in Indonesia over a decade and a half, this study reveals that an increase in temperature (e.g., due to natural variations or global warming) and, to a lesser extent, variations in rainfall are likely to have a greater effect on permanent outmigration of households than natural disasters.