bluuebunny/crossref_metadata_2025 huggingface dataset:
Non-precious alloy encapsulated in nitrogen-doped graphene layers derived from MOFs as an active and durable hydrogen evolution reaction catalyst
Authors: Yang Yang , Lun Zhengyan , Xia Guoliang , Zheng Fangcai , He Mengni , Chen Qianwang
Published: October 2015

An FeCo alloy covered with nitrogen doped graphene is prepared by direct annealing of Fe3[Co(CN)6]2nanoparticles, exhibiting efficient HER catalysis.
Reply to the Comment on “Grazing incidence X-ray fluorescence of periodic structures – a comparison between X-ray standing waves and geometrical optics calculations”
Authors: Nowak Stanisław H. , Beckhoff Burkhard , Reinhardt Falk , Dousse Jean-Claude
Published: October 2015

We respond to the comment by W. Jark and D. Eichert on our earlier article concerning geometrical optics based data interpretation of grazing incidence X-ray fluorescence experiments.
Multiple ion counting measurement strategies by SIMS – a case study from nuclear safeguards and forensics
Authors: Hedberg P. M. L. , Peres P. , Fernandes F. , Renaud L.
Published: October 2015

This paper describes and discusses how isotope measurements of low content uranium materials can be optimized using a multi-ion counting system consisting of five discrete dynode electron multiplier (EM) detectors.
Microfluidic devices to enrich and isolate circulating tumor cells
Authors: Myung J. H. , Hong S.
Published: October 2015

Detection of circulating tumor cells (CTCs) in blood has been extensively investigated to use them as a biomarker for the diagnosis and prognosis of various cancers. This review provides a comprehensive overview of recent advances in CTC detection achieved through application of microfluidic devices and the challenges that these promising technologies must overcome to be clinically impactful.
Boosting the electron mobility of solution-grown organic single crystals via reducing the amount of polar solvent residues
Authors: Xue Guobiao , Wu Jiake , Fan Congcheng , Liu Shuang , Huang Zhuoting , Liu Yujing , Shan Bowen , Xin Huolin L. , Miao Qian , Chen Hongzheng , Li Hanying
Published: October 2015

The electron mobility of solution-grown TIPS-TAP single crystals has been boosted to 13.3 cm2V−1s−1, after removing the polar solvent residues.
Synthesis and mode of action of oligomeric sesquiterpene lactones
Authors: Li Chao , Jones Alexander X. , Lei Xiaoguang
Published: October 2015

In this highlight we describe two case studies from our laboratory, involving the biomimetic syntheses and the biological mechanism elucidation of the bioactive oligomeric sesquiterpenoids, (+)-ainsliadimer A (4) and (−)-ainsliatrimer A (5).
Ultrafast static and diffusion-controlled electron transfer at Ag29 nanocluster/molecular acceptor interfaces
Authors: Aly Shawkat M. , AbdulHalim Lina G. , Besong Tabot M. D. , Soldan Giada , Bakr Osman M. , Mohammed Omar F.
Published: October 2015

We quantitatively separate the contributions of static and collision-caused photo-induced electron transfer from Ag29NC clusters to MV2+ through both transient absorption and time-resolved fluorescence experiments.
Electrical release of dopamine and levodopa mediated by amphiphilic β-cyclodextrins immobilized on polycrystalline gold
Authors: Foschi Giulia , Leonardi Francesca , Scala Angela , Biscarini Fabio , Kovtun Alessandro , Liscio Andrea , Mazzaglia Antonino , Casalini Stefano
Published: October 2015

Vesicles of cationic amphiphilic β-cyclodextrins have been immobilized on polycrystalline gold by exploiting the chemical affinity between their amino groups and Au atoms.
CoPt/CeO2 catalysts for the growth of narrow diameter semiconducting single-walled carbon nanotubes
Authors: Tang Lei , Li Taotao , Li Chaowei , Ling Lin , Zhang Kai , Yao Yagang
Published: October 2015

The selective growth of narrow diameter distributed semiconducting SWNTs using CoPt/CeO2 catalysts has been achieved by dispersing the catalysts onto substrates, followed by oxidation and sintering in a general CVD system for specific SWNT growth.
Synthesis, characterization and enhanced gas sensing performance of porous ZnCo2O4 nano/microspheres
Authors: Liu Tie , Liu Jingyuan , Liu Qi , Song Dalei , Zhang Hongseng , Zhang Hongquan , Wang Jun
Published: October 2015

Porous and hollow ZnCo2O4 nano/microspheres have been successfully prepared by a facile one-pot solvothermal process and subsequent annealing. Gas test results indicate the porous spinel-type compounds have a superb kinetic response and excellent selectivity to ethanol at 175 °C.
Surface effects in metal oxide-based nanodevices
Authors: Lien Der-Hsien , Durán Retamal José Ramón , Ke Jr-Jian , Kang Chen-Fang , He Jr-Hau
Published: October 2015

The surface effect can be either a negative or beneficial effect on nanodevices depending on the environmental conditions and device applications. This review provides an introduction of the surface effects on different types of nanodevices, offering the solutions to response to their benefits and negative effect, and provides outlooks on further applications regarding the surface effect.
Synthesis and biological evaluation of analogs of AAL(S) for use as ceramide synthase 1 inhibitors
Authors: Toop Hamish D. , Don Anthony S. , Morris Jonathan C.
Published: October 2015

This work has led to the identification of a selective CerS1 inhibitor that is non-cytotoxic.
Enantioselective synthesis of (−)-chloramphenicol via silver-catalysed asymmetric isocyanoacetate aldol reaction
Authors: Franchino Allegra , Jakubec Pavol , Dixon Darren J.
Published: October 2015

A concise synthesis of (−)-chloramphenicol, based on the catalytic asymmetric aldol reaction between 4-nitrobenzaldehyde and benzhydryl isocyanoacetate, is reported.
Simple separation and characterization of lanthanide–polyaminocarboxylic acid complexes by HILIC ESI-MS
Authors: Beuvier L. , Bresson C. , Nonell A. , Vio L. , Henry N. , Pichon V. , Chartier F.
Published: October 2015

Lanthanide complexes with EDTA and DTPA ligands were separated and characterized by HILIC ESI-MS for the first time.
Starch–borate–graphene oxide nanocomposites as highly efficient targeted antitumor drugs
Authors: Cheng Rumei , Ou Shengju , Bu Yexu , Li Xuan , Liu Xiaohong , Wang Yuqin , Guo Rui , Shi Bingyang , Jin Dayong , Liu Yong
Published: October 2015

Novel antitumor drugs, compatible with normal cells but highly toxic against cancer cells, were prepared from starch–borate–graphene oxide (SBG) nanocomposites.
Disulfide-based metal-free α-sulfanylation of ketones
Authors: Vaquer Andrea F. , Frongia Angelo , Secci Francesco , Tuveri Enrica
Published: October 2015

An eco-friendly methodology for the direct α-sulfanylation of ketones has been developed by using diaryl disulfides as sulfanyl source affording ketosulfides in good to excellent yields and high selectivity.
Four solid forms of tauroursodeoxycholic acid and solid-state transformations: effects of temperature and milling
Authors: Xu Kailin , Zheng Shoujun , Guo Liuqi , Li Shanshan , Wang Lili , Tang Peixiao , Yan Jin , Wu Di , Li Hui
Published: October 2015

TUDCA solid forms were characterized. Temperature-triggered and mechanical activated solid-state transformation, as environmental-friendly methods, were successfully used for getting new solid forms and studying solid-state transformations procedure.
Facile synthesis of magnetic Fe3O4/CeCO3OH composites with excellent adsorption capability for small cationic dyes
Authors: Li Keyan , Chai Fanfan , Zhao Yongqin , Guo Xinwen
Published: October 2015

A magnetic Fe3O4/CeCO3OH composite prepared through a one-step hydrothermal route exhibits maximum adsorption capacity of 666.2 mg g−1 for MB.
Layered double hydroxide-decorated flexible polyurethane foam: significantly improved toxic effluent elimination
Authors: Liu Lei , Wang Wei , Hu Yuan
Published: October 2015

A layered double hydroxide-based fire-blocking coating was deposited on the surface of a flexible polyurethane foam using a layer-by-layer method to improve its thermal stability, flame retardancy and smoke suppression properties.
Pyrolyzed egg yolk as an efficient bifunctional electrocatalyst for oxygen reduction and evolution reactions
Authors: Shao Zechao , Zhang Wen , An De , Zhang Genlei , Wang Yuxin
Published: October 2015

A novel electrocatalyst of heteroatom-doped carbon (HDC) has been developed via facile pyrolysis of hen egg yolk without incorporating external heteroatoms.
Catalytic insertion of E–H bonds (E = C, N, P, S) into heterocumulenes by amido–actinide complexes
Authors: Batrice Rami J. , Eisen Moris S.
Published: October 2015

We report herein the actinide-mediated insertion of E–H bonds (E = C, N, P, S) into various heterocumulenes including carbodiimides, isocyanates, and isothiocyanates.
Understanding geometric instabilities in thin films via a multi-layer model
Authors: Lejeune Emma , Javili Ali , Linder Christian
Published: October 2015

In thin films, the contribution of inhomogeneities due to interfacial regions with finite thickness cannot be ignored. We introduce a multi-layer model for wrinkling initiation in thin films adhered to compliant substrates as an analytical solution verified by numerical results.
Fluorescent probes for the detection of cyanide ions in aqueous medium: cellular uptake and assay for β-glucosidase and hydroxynitrile lyase
Authors: Agarwalla Hridesh , Gangopadhyay Monalisa , Sharma Dharmendar Kumar , Basu Santanu Kumar , Jadhav Sameer , Chowdhury Arindam , Das Amitava
Published: October 2015

A chemodosimetric reagent for specific detection of cyanide species and its possible use in imaging applications as well as assay development for important enzymes.
Maximizing the thiol-activated photodynamic and fluorescence imaging functionalities of theranostic reagents by modularization of Bodipy-based dyad triplet photosensitizers
Authors: Zhao Jianzhang , Huang Ling , Cui Xiaoneng , Li Shujing , Wu Huijian
Published: October 2015

The fluorescence imaging and singlet oxygen production ability of thiol-cleavable triplet photosensitizers was maximized by disintegration of the functionalities.
Ultrahigh performance negative thermal-resistance switching based on individual ZnO:K, Cl micro/nanowires for multibit nonvolatile resistance random access memory dual-written/erased repeatedly by temperature or bias
Authors: Zhao Jie , Cheng Baochang , Xiao Yanhe , Guo Rui , Lei Shuijin
Published: October 2015

Nonvolatile multibit sensor and memory written/erased by temperature or bias is realized in two-terminal device based on individual ZnO : K, Cl micro/nanowire.
The effect of manganite nanoparticle addition on the low field magnetoresistance of polyaniline
Authors: Romero Mariano , Faccio Ricardo , Pardo Helena , Tumelero Milton A. , Montenegro Benjamín , Campos Plá Cid Cristiani , Pasa André A. , Mombrú Álvaro W.
Published: October 2015

In this report, we studied the effect of the addition of manganite nanoparticles on the microstructure and magnetotransport properties of polyaniline polymers.
Efficient tone reservation peak‐to‐average power ratio reduction system with optimal clipping for orthogonal frequency division multiplexing systems
Authors: Lv Xin , Wan Yi
Published: October 2015

In this study, the authors propose an efficient peak‐to‐average power ratio (PAPR) reduction system for OFDM transmission based on tone reservation (TR). In this system, a novel cost function to jointly optimise the clipping level and the peak‐cancelling signal is proposed. The obtained optimal clipping level can not only render the clipping noise to be well approximated by the reserved tones, but also be small enough to deeply suppress the peaks. In addition, a new cyclic method to optimise the peak‐cancelling signal and the clipping level is presented with the insight that when optimising the reserved tone values, the time‐domain signal to be thresholded itself depends on the peak‐cancelling signal instead of being constant, as assumed by many other methods. Simulation results show that the proposed system significantly improves the PAPR reduction performance over the state‐of‐the‐art clipping‐based TR algorithms.
Cooperative communication with energy‐harvesting relays under physical layer security
Authors: Son Pham Ngoc , Kong Hyung Yun
Published: October 2015

In this study, the authors propose a cooperative transmission scheme with energy‐harvesting (EH) relays under wiretapping of an eavesdropper. In this scheme, the relays harvest energy from radio‐frequency (RF) signals of a source through power‐splitting receivers, and process arrived signals by amplify‐and‐forward (EH‐AF protocol) and decode‐and‐forward (EH‐DF protocol) technologies. In the proposed protocols, a best relay is selected at the destination so that the end‐to‐end achievable secrecy rates are maximal. Exact and asymptotic secrecy outage probability expressions are used to evaluate the EH‐AF and EH‐DF protocols, respectively, and are confirmed by Monte Carlo simulations. The simulation results show that (i) the EH‐DF protocol outperforms the EH‐AF protocol, and both proposed protocols are improved when the number of cooperative relays and the distances of the relay–eavesdropper links increase and the relays move toward the destination, (ii) the secrecy performance of the EH‐AF and EH‐DF protocols is the best at optimal power‐splitting ratios, which are obtained by the golden section search method, (iii) the energy conversion efficiency and the noise at RF‐to‐baseband conversion units seriously affect the proposed protocols, and finally, (iv) the theoretical analysis results fit those of the Monte Carlo simulations.
Investigations on AC pollution flashover performance of insulator string under different non‐uniform pollution conditions
Authors: Zhang Zhijin , You Jinwei , Wei Donghong , Jiang Xingliang , Zhang Dongdong , Bi Maoqiang
Published: October 2015

Observations of contamination tests showed that, the contamination distribution of insulators is usually uneven. In this study, the solid layer method was used to imitate different non‐uniform pollution conditions and the AC pollution flashover tests of 7‐unit insulators were carried out. The results indicate that the increase of uneven pollution degree J from 1 to 15 will give a 39% raise of U50 under non‐uniform pollution on top and bottom surfaces, a 23% decrease for fan‐shaped non‐uniform pollution and a 21% higher U50 with ring‐shaped non‐uniform pollution. A higher occupation ratio (k) of leeward side will reduce U50 under fan‐shaped non‐uniform pollution and a bigger radius R of heavy polluted area has certain effect on U50 for ring‐shaped non‐uniform pollution. The U50 and salt deposit density still can be expressed by the negative power function, and non‐uniform pollution conditions and J have great effect on a, but less impact on n. The correction equations of different non‐uniform pollution conditions are obtained and the relative errors are acceptable. The research has certain reference significance for the design and selection of AC transmission line external insulation.
Ultra wideband antenna design using discrete Green's functions in conjunction with binary particle swarm optimisation
Authors: Mirhadi Salma , Komjani Nader , Soleimani Mohammad
Published: October 2015

The binary particle swarm optimisation (BPSO) in conjunction with the time‐domain discrete Green's function (DGF) method is proposed for designing of printed ultra wideband (UWB) antennas. In the DGF method, on one hand, a three‐dimensional problem is reduced to a two‐dimensional one, and on the other hand, the broadband frequency characteristics of the antenna are achieved with a single simulation run. Furthermore, the spatial discrete representation of the current on the antenna, in the DGF method, facilitates implementation of its combination with the BPSO algorithm. Two different UWB antennas are designed using the proposed approach. First, an antenna is designed to minimise voltage standing wave ratio (VSWR). The experimental result shows that the antenna has a VSWR about <1.5 over the UWB range. Second, an antenna is designed to have not only low VSWR, but also stable radiation pattern over the UWB range. The experimental results show a good impedance matching and stable omnidirectional pattern over the UWB range.
Zero voltage transition–zero current transition pulse‐width modulated multiphase synchronous buck converter with an active auxiliary circuit for portable applications
Authors: Panda Anup Kumar , Kumar Sarode Shiva , Ramesh Tejavathu
Published: October 2015

In this study, a zero voltage transition (ZVT)–zero current transition (ZCT) pulse‐width modulated (PWM) multiphase synchronous buck converter (SBC), with an active auxiliary circuit is proposed, that reduces the stresses and enhances the efficiency abating the switching and conduction losses of the converter. The important design feature of ZVT–ZCT PWM multiphase SBC converters is the placement of resonant components that pacifies the switching and conduction losses. Due to the ZVT–ZCT, the resonant components with low values are used that results in the increase of switching frequency. High current multiphase buck converters found applications in the advanced data control, solid state lasers, communication equipment, Pentium processors etc. The ZVT–ZCT operation of the proposed converter is presented through theoretical analysis. A simple design method for the auxiliary circuit is discussed. The characteristics of the proposed converter are verified with the simulation in the PSIM co‐simulated with MATLAB/SIMULINK environment and validated with experimental results.
Voltage and power control used to stabilise the distributed generation system for stand‐alone or grid‐connected operation
Authors: Gonçalves Amilcar Flamarion Querubini , Aguiar Cassius R. , Bastos Renan F. , Pozzebon Giovani G. , Machado Ricardo Q.
Published: October 2015

This study presents a control strategy for managing power delivered to, or absorbed from, the grid, independent of local load or grid characteristics. To achieve this objective, the strategy requires the use of three levels of control structures. The first is related to phase‐locked loop and grid‐tie algorithms, which are employed to minimise disturbances during the grid connection. The second, which produces voltages with reduced harmonics levels at the distributed generation (DG) terminals, comprises the cascade voltage and current control. The third structure is the active and reactive power control mechanisms, which uses the angle of displacement and the adjusting of the DG voltage amplitude to keep the power flow through the grid at a specific set‐point, independent of local load characteristics. In addition, the power control structures have to operate in a decoupled operation mode, whereby the active power control has to be faster than the reactive power control, or vice versa. In terms of their physical structure, a passive LCL filter is used to connect the voltage source inverter to the grid. To verify the findings and observations discussed in this study, a set of simulations and experimental results are presented.
Extended maximum boost control scheme based on single‐phase modulator for three‐phase Z‐source inverter
Authors: Sabeur Nassereddine , Mekhilef Saad , Masaoud Ammar
Published: October 2015

This study proposes a new control method for Z‐source inverter (ZSI) – called the one‐dimension ZSI (ODZSI) – based on the single‐phase modulator technique. The notable feature of the proposed control compared with the space‐vector modulation strategy is its reduced computational processing time, which is attractive for digital implementation. Compared with the maximum boost control (MBC), which uses carrier‐based pulse width modulation control methods, the proposed algorithm enhances the output voltage and current quality. In this study, the results of MBC are compared with those obtained with a single‐phase modulator for three‐phase ZSI showing its advantage for improving the line output current and voltage total harmonic distortion. The obtained simulation and hardware results ensure the feasibility and validate the performance of the ODZSI modulation method applied to each phase. The proposed method is easier for digital implementation with less computation, and will be beneficial for further industrial applications of ZSIs. The simulation results are carried out using MATLAB/Simulink, and the hardware performance are provided and discussed.
Doppler spectra of medium grazing angle sea clutter; part 1: characterisation
Authors: Watts Simon , Rosenberg Luke , Bocquet Stephen , Ritchie Matthew
Published: October 2015

This study is concerned with the characterisation of Doppler spectra from high range resolution X‐band radar sea clutter observed from an airborne platform over the range of grazing angles, 15° to 45°. It is observed that when looking up or down wind there is a strong correlation between mean Doppler shift and local spectrum intensity. When combined with random fluctuations of spectrum width, these characteristics give the spectra a temporal and spatial variability. This behaviour has previously been observed in low grazing angle data and these results confirm the wider applicability of the models developed using that data. The modelling method is also extended here to capture the bimodal behaviour observed with high intensity returns from breaking waves looking up or down‐wind.
Third-order superintegrable systems with potentials satisfying only nonlinear equations
Authors: Marchesiello A. , Post S. , Šnobl L.
Published: October 2015

The conditions for superintegrable systems in two-dimensional Euclidean space admitting separation of variables in an orthogonal coordinate system and a functionally independent third-order integral are studied. It is shown that only systems that separate in subgroup type coordinates, Cartesian or polar, admit potentials that can be described in terms of nonlinear special functions. Systems separating in parabolic or elliptic coordinates are shown to have potentials with only non-movable singularities.
Use of a priori spectral information in the measurement of x-ray flux with filtered diode arrays
Authors: Marrs R. E. , Widmann K. , Brown G. V. , Heeter R. F. , MacLaren S. A. , May M. J. , Moore A. S. , Schneider M. B.
Published: October 2015

Filtered x-ray diode (XRD) arrays are often used to measure x-ray spectra vs. time from spectrally continuous x-ray sources such as hohlraums. A priori models of the incident x-ray spectrum enable a more accurate unfolding of the x-ray flux as compared to the standard technique of modifying a thermal Planckian with spectral peaks or dips at the response energy of each filtered XRD channel. A model x-ray spectrum consisting of a thermal Planckian, a Gaussian at higher energy, and (in some cases) a high energy background provides an excellent fit to XRD-array measurements of x-ray emission from laser heated hohlraums. If high-resolution measurements of part of the x-ray emission spectrum are available, that information can be included in the a priori model. In cases where the x-ray emission spectrum is not Planckian, candidate x-ray spectra can be allowed or excluded by fitting them to measured XRD voltages. Examples are presented from the filtered XRD arrays, named Dante, at the National Ignition Facility and the Laboratory for Laser Energetics.
Three-dimensional imaging of carbonyl sulfide and ethyl iodide photodissociation using the pixel imaging mass spectrometry camera
Authors: Amini K. , Blake S. , Brouard M. , Burt M. B. , Halford E. , Lauer A. , Slater C. S. , Lee J. W. L. , Vallance C.
Published: October 2015

The Pixel Imaging Mass Spectrometry (PImMS) camera is used in proof-of-principle three-dimensional imaging experiments on the photodissociation of carbonyl sulfide and ethyl iodide at wavelengths around 230 nm and 245 nm, respectively. Coupling the PImMS camera with DC-sliced velocity-map imaging allows the complete three-dimensional Newton sphere of photofragment ions to be recorded on each laser pump-probe cycle with a timing precision of 12.5 ns, yielding velocity resolutions along the time-of-flight axis of around 6%–9% in the applications presented.
Detailed beam and plasma measurements on the vessel for extraction and source plasma analyses (VESPA) Penning H− ion source
Authors: Lawrie S. R. , Faircloth D. C. , Letchford A. P. , Whitehead M. O. , Wood T.
Published: October 2015

A vessel for extraction and source plasma analyses (VESPA) is operational at the Rutherford Appleton Laboratory (RAL). This project supports and guides the overall ion source R&D effort for the ISIS spallation neutron and muon facility at RAL. The VESPA produces 100 mA of pulsed H− beam, but perveance scans indicate that the source is production-limited at extraction voltages above 12 kV unless the arc current is increased. A high resolution optical monochromator is used to measure plasma properties using argon as a diagnostic gas. The atomic hydrogen temperature increases linearly with arc current, up to 2.8 eV for 50 A; whereas the electron temperature has a slight linear decrease toward 2.2 eV. The gas density is 1021 m−3, whilst the electron density is two orders of magnitude lower. Densities follow square root relationships with arc current, with gas density decreasing whilst electron (and hence ion) density increases. Stopping and range of ions in matter calculations prove that operating a high current arc with an argon admixture is extremely difficult because cathode-coated cesium is heavily sputtered by argon.
The characteristic of evaporative cooling magnet for ECRIS
Authors: Xiong B. , Ruan L. , Gu G. B. , Lu W. , Zhang X. Z. , Zhan W. L.
Published: October 2015

Compared with traditional de-ionized pressurized-water cooled magnet of ECRIS, evaporative cooling magnet has some special characteristics, such as high cooling efficiency, simple maintenance, and operation. The analysis is carried out according to the design and operation of LECR4 (Lanzhou Electron Cyclotron Resonance ion source No. 4, since July 2013), whose magnet is cooled by evaporative cooling technology. The insulation coolant replaces the de-ionized pressurized-water to absorb the heat of coils, and the physical and chemical properties of coolant remain stable for a long time with no need for purification or filtration. The coils of magnet are immersed in the liquid coolant. For the higher cooling efficiency of coolant, the current density of coils can be greatly improved. The heat transfer process executes under atmospheric pressure, and the temperature of coils is lower than 70 °C when the current density of coils is 12 A/mm2. On the other hand, the heat transfer temperature of coolant is about 50 °C, and the heat can be transferred to fresh air which can save cost of water cooling system. Two years of LECR4 stable operation show that evaporative cooling technology can be used on magnet of ECRIS, and the application advantages are very obvious.
The influence of surface preparation on low temperature HfO2 ALD on InGaAs (001) and (110) surfaces
Authors: Kent Tyler , Tang Kechao , Chobpattana Varistha , Negara Muhammad Adi , Edmonds Mary , Mitchell William , Sahu Bhagawan , Galatage Rohit , Droopad Ravi , McIntyre Paul , Kummel Andrew C.
Published: October 2015

Current logic devices rely on 3D architectures, such as the tri-gate field effect transistor (finFET), which utilize the (001) and (110) crystal faces simultaneously thus requiring passivation methods for the (110) face in order to ensure a pristine 3D surface prior to further processing. Scanning tunneling microscopy (STM), x-ray photoelectron spectroscopy (XPS), and correlated electrical measurement on MOSCAPs were utilized to compare the effects of a previously developed in situ pre-atomic layer deposition (ALD) surface clean on the InGaAs (001) and (110) surfaces. Ex situ wet cleans are very effective on the (001) surface but not the (110) surface. Capacitance voltage indicated the (001) surface with no buffered oxide etch had a higher Cmax hypothesized to be a result of poor nucleation of HfO2 on the native oxide. An in situ pre-ALD surface clean employing both atomic H and trimethylaluminum (TMA) pre-pulsing, developed by Chobpattana et al. and Carter et al. for the (001) surface, was demonstrated to be effective on the (110) surface for producing low Dit high Cox MOSCAPs. Including TMA in the pre-ALD surface clean resulted in reduction of the magnitude of the interface state capacitance. The XPS studies show the role of atomic H pre-pulsing is to remove both carbon and oxygen while STM shows the role of TMA pre-pulsing is to eliminate H induced etching. Devices fabricated at 120 °C and 300 °C were compared.
Analyzing the special PFG signal attenuation behavior of intermolecular MQC via the effective phase shift diffusion equation method
Authors: Lin Guoxing
Published: October 2015

Inter-molecular multiple quantum coherence (iMQC) has important applications in NMR and MRI. However, the current theoretical methods still have some difficulties in analyzing the behavior of iMQC signal attenuation of pulsed field gradient diffusion experiments. In this paper, the iMQC diffusion experiments were analyzed by an effective phase shift diffusion equation (EPSDE) method, which is based on the idea that the accumulating phase shift (APS) can be viewed as the result of a diffusion process in virtual phase space (VPS) with effective diffusion coefficient K2(t) D (rad2/s) where K(t)=∫0tγg(t′)dt′ is a wavenumber and D is the physical diffusion coefficient of the spin carrier in the real space. The term K(ttot) z1 needs to be added to the APS when K(ttot) is not zero. Most of the time, K(ttot) equals zero. However, in iMQC experiments, the condition K(ttot) equaling zero or being non-zero for each spin depends on the gradient pulse setting. The signal attenuations of these two types of iMQC, zero or non-zero K(ttot), were analyzed in detail for free and restricted diffusions, which shows that there are significant differences between these two types of iMQC. Particularly, if an apparent diffusion coefficient Dapp is used to analyze the signal attenuation, it equals nD for zero K(ttot) which agrees with current theoretical and experimental reports, while for non-zero K(ttot), it equals (2n − 1) D which agrees with experimental results from the literature; there are no similar theoretical results reported for comparison. The result that Dapp equals (2n − 1) D is important because the higher value of Dapp means that non-zero K(ttot) iMQC can potentially provide more contrast and measure slower diffusion rates than zero K(ttot) iMQC. The EPSDE method provides a new way to analyze iMQC diffusion experiments.
Effects of spin-orbit coupling on laser cooling of BeI and MgI
Authors: Wan Mingjie , Huang Duohui , Shao Juxiang , Yu You , Li Song , Li Yuanyuan
Published: October 2015

We present the ab initio study of spin-orbit coupling effects on laser cooling of BeI and MgI molecules. Potential energy curves for the X2Σ+1/2, A2Π1/2,3/2, and 22Π3/2,1/2 states are calculated using multi-reference configuration interaction method plus Davidson corrections. Spectroscopic parameters of BeI and MgI are in excellent agreement with available experimental and theoretical values. The A2Π3/2 state of MgI is a repulsive state. It is an unsuitable scheme for the A2Π3/2(υ′)← X2Σ+1/2 (υ″) transition for laser cooling of MgI. Highly diagonally distributed Franck-Condon factors f00 for the A2Π1/2,3/2 (υ′ = 0) ← X2Σ+1/2 (υ″ = 0) transitions and suitable radiative lifetimes τ for the A2Π1/2,3/2 (υ′ = 0) of BeI and MgI are obtained. Three laser wavelength drives are required for the A2Π1/2,3/2(υ′)←X2Σ+1/2 (υ″) transitions of BeI and MgI. The proposed cooling wavelengths of BeI and MgI are both in the violet region. The results imply the feasibility of laser cooling of BeI and MgI, and that laser cooling of BeI is more possible.
Thermoelectric properties optimization of Fe2VGa by tuning electronic density of states via titanium doping
Authors: Wei Pai-Chun , Huang Ta-Sung , Lin Shu-Wei , Guo Guang-Yu , Chen Yang-Yuan
Published: October 2015

We report the correlation between thermoelectric properties and electronic band structure of thermoelectric Heusler alloy Fe2V1-xTixGa by comparing experimental measurements with theoretical calculations. The electrical resistivity data show that the semiconducting-like behavior of pure Fe2VGa is transformed to a more metallic-like behavior at x = 0.1. Meanwhile, an enhancement of the Seebeck coefficient was observed for all Ti doped specimens at elevated temperatures with a peak value of 57 μV/K for x = 0.05 at 300 K. The experimental results can be elucidated by the calculated band structure, i.e., a gradual shifting of the Fermi level from the middle of the pseudogap to the region of valence bands. With optimized doping, the thermoelectric power factor can be significantly enhanced to 3.95 mW m−1 K−2 at room temperature, which is comparable to the power factors of Bi2Te3-based compounds. The synergy of thermal conductivity reduction due to the alloying effect and the significant increase of the thermoelectric power factor leads to higher order zT values than that of prime Fe2VGa.
Irreversible entropy model for damage diagnosis in resistors
Authors: Cuadras Angel , Crisóstomo Javier , Ovejas Victoria J. , Quilez Marcos
Published: October 2015

We propose a method to characterize electrical resistor damage based on entropy measurements. Irreversible entropy and the rate at which it is generated are more convenient parameters than resistance for describing damage because they are essentially positive in virtue of the second law of thermodynamics, whereas resistance may increase or decrease depending on the degradation mechanism. Commercial resistors were tested in order to characterize the damage induced by power surges. Resistors were biased with constant and pulsed voltage signals, leading to power dissipation in the range of 4–8 W, which is well above the 0.25 W nominal power to initiate failure. Entropy was inferred from the added power and temperature evolution. A model is proposed to understand the relationship among resistance, entropy, and damage. The power surge dissipates into heat (Joule effect) and damages the resistor. The results show a correlation between entropy generation rate and resistor failure. We conclude that damage can be conveniently assessed from irreversible entropy generation. Our results for resistors can be easily extrapolated to other systems or machines that can be modeled based on their resistance.
Low-temperature scintillation properties of CaWO4 crystals for rare-event searches
Authors: v. Sivers M. , Clark M. , Di Stefano P. C. F. , Erb A. , Gütlein A. , Lanfranchi J.-C. , Münster A. , Nadeau P. , Piquemal M. , Potzel W. , Roth S. , Schreiner K. , Strauss R. , Wawoczny S. , Willers M. , Zöller A.
Published: October 2015

In prospect of its application in cryogenic rare-event searches, we have investigated the low-temperature scintillation properties of CaWO4 crystals down to 3.4 K under α and γ excitation. Concerning the scintillation decay times, we observe a long component in the ms range which significantly contributes to the light yield below 40 K. For the first time we have measured the temperature dependence of the α/γ-ratio of the light yield. This parameter, which can be used to discriminate α and γ events in scintillating bolometers, is found to be ∼8%–15% smaller at low temperatures compared to room temperature.
Nanocluster ionization energies and work function of aluminum, and their temperature dependence
Authors: Halder Avik , Kresin Vitaly V.
Published: October 2015

Ionization threshold energies of Aln (n = 32-95) nanoclusters are determined by laser ionization of free neutral metal clusters thermalized to several temperatures in the range from 65 K to 230 K. The photoion yield curves of cold clusters follow a quadratic energy dependence above threshold, in agreement with the Fowler law of surface photoemission. Accurate data collection and analysis procedures make it possible to resolve very small (few parts in a thousand) temperature-induced shifts in the ionization energies. Extrapolation of the data to the bulk limit enables a determination of the thermal shift of the polycrystalline metal work function, found to be in excellent agreement with theoretical prediction based on the influence of thermal expansion. Small clusters display somewhat larger thermal shifts, reflecting their greater susceptibility to thermal expansion. Ionization studies of free size-resolved nanoclusters facilitate understanding of the interplay of surface, electronic, and lattice properties under contamination-free conditions.
A computational study of the electronic properties of one-dimensional armchair phosphorene nanotubes
Authors: Yu Sheng , Zhu Hao , Eshun Kwesi , Arab Abbas , Badwan Ahmad , Li Qiliang
Published: October 2015

We have performed a comprehensive first-principle computational study of the electronic properties of one-dimensional phosphorene nanotubes (PNTs), and the strain effect on the mechanical and electrical properties of PNTs, including the elastic modulus, energy bandstructure, and carrier effective mass. The study has demonstrated that the armchair PNTs have semiconducting properties along the axial direction and the carrier mobility can be significantly improved by compressive strain. The hole mobility increases from 40.7 cm2/V s to 197.0 cm2/V s as the compressive strain increases to −5% at room temperature. The investigations of size effect on armchair PNTs indicated that the conductance increases significantly as the increasing diameter. Overall, this study indicated that the PNTs have very attractive electronic properties for future application in nanomaterials and devices.
A tunable microwave plasma photonic crystal filter
Authors: Wang B. , Cappelli M. A.
Published: October 2015

The integration of gaseous plasma elements into a microwave photonic crystal band gap cavity structure allows for active tuning of the device. An alumina rod array microwave photonic crystal waveguide resonator is simulated and characterized through finite difference time domain methods. A gaseous plasma element is integrated into the cavity structure and the effect of plasma density on the transmission properties of the structure is investigated. We show, through both simulations and experiments, that the permittivity of the plasma can be adjusted to shift the peak resonance to allow for both switching and tunability of transmission. The experimentally measured peak shifts in transmission are compared to those simulated and the electron density of the gaseous plasma element is calculated and compared to values determined from the measured discharge current density.
Exchange bias of CoO1−δ/(NiFe,Fe) system with blocking temperature beyond Néel temperature of bulk CoO
Authors: Ding S. L. , Wu R. , Fu J. B. , Wen X. , Du H. L. , Liu S. Q. , Han J. Z. , Yang Y. C. , Wang C. S. , Zhou D. , Yang J. B.
Published: October 2015

The exchange bias effects in pulsed laser deposited CoO1−δ/(NiFe,Fe) bilayers were investigated. An anomalously high blocking temperature (TB) of 325 K was obtained for the as-deposited CoO1−δ/ferromagnet bilayers, which is 33 K higher than the Néel temperature of the bulk CoO (TN = 292 K). The amount of oxygen vacancies δ in the CoO1−δ film can be controlled by a post-annealing treatment in the O2 atmosphere. The TB of the CoO1−δ/ferromagnet bilayers increases with an increasing δ from δ = 0 to δ = 0.16. Our results indicate that the high TB of CoO1−δ/ferromagnet bilayers originates from the enhancement of the magnetic interaction in the CoO1−δ layer owing to O2− vacancies.
Stratification in Al and Cu foils exploded in vacuum
Authors: Baksht R. B. , Rousskikh A. G. , Zhigalin A. S. , Oreshkin V. I. , Artyomov A. P.
Published: October 2015

An experiment with exploding foils was carried out at a current density of 0.7 × 108 A/cm2 through the foil with a current density rise rate of about 1015 A/cm2 s. To record the strata arising during the foil explosions, a two-frame radiographic system was used that allowed tracing the dynamics of strata formation within one shot. The original striation wavelength was 20–26 μm. It was observed that as the energy deposition to a foil stopped, the striation wavelength increased at a rate of ∼(5–9) × 103 cm/s. It is supposed that the most probable reason for the stratification is the thermal instability that develops due to an increase in the resistivity of the metal with temperature.
Three-wave coupling coefficients for perpendicular wave propagation in a magnetized plasma
Authors: Brodin G. , Stenflo L.
Published: October 2015

The resonant interaction between three waves in a uniform magnetized plasma is reconsidered. Starting from previous kinetic expressions, we limit our investigation to waves propagating perpendicularly to the external magnetic field. It is shown that reliable results can only be obtained in the two-dimensional case, i.e., when the wave vectors have both x and y components.
Dielectric function of polycrystalline α-Ag2S by spectroscopic ellipsometry
Authors: Diware M. S. , Ganorkar S. P. , Kim J. , Bramhe S. N. , Cho H. M. , Cho Y. J. , Chegal W.
Published: October 2015

Complex optical properties (ε=ε1+iε2) of polycrystalline bulk α-Ag2S are investigated by spectroscopic ellipsometry from 0.5 to 8.5 eV at room temperature. The acanthite structure (monoclinic) of α-Ag2S is confirmed by structural analysis. Multilayer analysis with Tauc-Lorentz dispersion model is applied to draw out ε from ellipsometric data. Ag2S shows absorption in the entire range of the visible spectrum with onset band gap of 1.07 eV; furthermore, six other interband transitions are identified whose energy positions accurately obtained by standard lineshape analysis of second-energy-derivative of point-by-point fit determined ε. Finally, we compared our data with reported theoretically calculated data, and origin of the main optical structures is discussed.
Metallosupramolecular Chemistry of AgI Complexes with Azobis(2-pyridine) and its Derivatives
Authors: Rajan Siji , Keene F. Richard , Steel Peter J.
Published: October 2015

Reactions of three azobis(2-pyridines) with silver salts lead to 1D coordination polymers whose structures have been determined by single crystal X-ray crystallography. The azobis(2-pyridines) consistently act as di-bidentate ligands that bridge silver atoms separated by distances ranging from 5.49 to 5.82 Å. Two of the coordination polymers consist of chains in which consecutive bridging ligands are orthogonally oriented. The other polymer has a considerably more complicated structure due to the more intimate involvement of the trifluoroacetate counteranions, which also act as bridges between silver centres.
Dynamics of phosphorus fractions in the rhizosphere of fababean (Vicia faba L.) and maize (Zea mays L.) grown in calcareous and acid soils
Authors: Li Guohua , Li Haigang , Leffelaar Peter A. , Shen Jianbo , Zhang Fusuo
Published: October 2015

The dynamics of soil phosphorus (P) fractions were investigated, in the rhizosphere of fababean (Vicia faba L.) and maize (Zea mays L.) grown in calcareous and acid soils. Plants were grown in a mini-rhizotron with a thin (3 mm) soil layer, which was in contact with the root-mat, and considered as rhizosphere soil. Hedley sequential fractionation was used to evaluate the relationship between soil pH and P dynamics in the rhizosphere of fababean and maize. Soil pH influenced the dynamics of P fractions in both calcareous and acid soils. Fababean and maize roots decreased rhizosphere pH by 0.4 and 0.2 pH units in calcareous soil, and increased rhizosphere pH by 1.2 and 0.8 pH units in acid soil, respectively, compared with the no-plant control. The acid-soluble inorganic P fraction in the rhizosphere of calcareous soil was significantly depleted by fababean, which was probably due to strong rhizosphere acidification. In contrast, maize had little effect on this fraction. Both fababean and maize significantly depleted the alkali-soluble organic P fractions in calcareous soil, but not in acid soil. Fababean and maize utilised different P fractions in soil, which was partly due to their differing abilities to modify the rhizosphere. This study has decoupled successfully the effects of chemically induced pH change from plant growth effects (such as mineralisation and P uptake) on P dynamics. The effect of soil pH on plant exudation response in P-limited soils has been demonstrated in the present study.
Sugarcane seed composition and changes during artificial ageing
Authors: Siqueira G. F. , Pierre J. S. , El Tahchy A. , Glassop D. , Singh S. , Bonnett G. D. , Rae A. L.
Published: October 2015

Sugarcane (Poaceae) has not undergone any commercial selection based upon seed characteristics. As the plant is grown from vegetative cuttings and the stalk harvested for its sucrose content, relatively little is known about its seed compared with other grass crops. The seeds of sugarcane were small, 1.8 × 0.8 mm, and the embryo comprised about one-third of the seed volume. Among the samples analysed, the seed contained on average 37%, 20% and 10% of the fresh weight as starch, protein and lipid, respectively. Histochemical staining showed that the starch was confined to the endosperm and the lipid to the embryo and aleurone layer. Protein was found in the embryo, endosperm and aleurone layer. There were small but significant differences between the sources of sugarcane seed. The wild relative S. spontaneum had significantly less starch than the commercial hybrid sugarcane seed. The lipid content was higher for sugarcane seed than for the seeds of many other grasses, possibly because of the high ratio of lipid-containing embryo to endosperm. Following artificial ageing, the observed decline in seed viability was not closely reflected by any significant changes in composition, although protein and sugars were reduced after 168 h. These results contribute to our understanding of the sexual reproductive biology of sugarcane, which is important for the science-based environmental risk evaluation of the release of genetically modified sugarcane.
Adaptation of wheat, barley, canola, field pea and chickpea to the thermal environments of Australia
Authors: Sadras Victor , Dreccer M. Fernanda
Published: October 2015

Warming trends involve two agronomically relevant aspects: a gradual increase in long-term mean temperature with the primary effect of shifting phenological patterns, and an increasing incidence of heat waves. Depending on timing, intensity and duration, heat can reduce crop growth and disrupt reproduction. Agronomic and breeding adaptations to elevated temperature have been listed but there is an overall lack of frameworks for systematic analysis. This paper provides agronomic and physiological background for the quantitative assessment of spatial patterns of the thermal regimes for wheat, barley, canola, field pea and chickpea. First, we revise the notion that Australian agriculture is ‘European’ and ill-adapted to the local environments. By showing that Australian agriculture in the southern and western regions is rather Levantine, we advance a more accurate and relevant framework to the thermal regimes of winter crops. Second, we outline the direct and indirect effects of temperature on crop traits and highlight the limitations of different approaches to investigate crop responses to temperature. This is important to make explicit the assumptions of studies dealing with crop responses to temperature; for example, indirect effects of temperature on crops mediated by effects on weeds, pathogens or herbivores could be important. Third, we compare the cardinal temperatures (including base, optimal, and critical thresholds) of our target crops. Cardinal temperatures respond to both natural and agronomic selection and are relevant for crop adaptation. Fourth, we develop a conceptual framework to assess thermal effects on crop yield and adaptive practices and traits, based on the notions of yield being a primary function of seed number, the species-specific critical window for the determination of seed number, and two complementary perspectives involving the photothermal quotient and crop growth rate in the critical window. The framework accounts for both aspects of warming: non-stressful elevated temperature and heat stress. Testable propositions are advanced that inform future research on crop adaptation to elevated temperature.