bluuebunny/crossref_metadata_2025 huggingface dataset:
The facile assembly of nanocrystals by optimizing humidity
Authors: Zhou Ming , Grahn Mattias , Zhou Han , Holmgren Allan , Hedlund Jonas
Published: September 2014

Humidity and substrate properties are considered coordinately in the assembly of nano-sized crystals. The nanocrystal monolayers with thicknesses of 20–100 nm show large-area uniformity and excellent orientations.
Single-crystal PbTiO3/PbZrO3 composite fibers formed by diffusion and epitaxial growth
Authors: Yu Tingting , Ren Zhaohui , Jiang Shan , Gong Siyu , Li Ming , Wei Xiao , Shen Ge , Han Gaorong
Published: September 2014

Single-crystal PbTiO3/PbZrO3 (PT/PZ) composite fibers were prepared under hydrothermal conditions for the first time, which had an epitaxial growth relationship between single-crystal perovskite PT nanofibers and PZ crystals.
A series of lanthanide(iii) complexes constructed from Schiff base and β-diketonate ligands
Authors: Sun Ou , Gao Ting , Sun Jingwen , Li Guangming , Li Hongfeng , Xu Hui , Wang Cheng , Yan Pengfei
Published: September 2014

Four type lanthanide(iii) complexes constructed from Schiff base and β-diketonate ligands have been synthesized by the same method. The structures were determined by single crystal X-ray crystallographic studies, and their luminescence properties were determined.
o-Benzyne fragmentation and isomerization pathways: a CASPT2 study
Authors: Ghigo Giovanni , Maranzana Andrea , Tonachini Glauco
Published: September 2014

The mechanism for the thermal fragmentation of o-benzyne to C4H2 + C2H2 and C6H2.
Epitope mapping of imidazolium cations in ionic liquid–protein interactions unveils the balance between hydrophobicity and electrostatics towards protein destabilisation
Authors: Silva Micael , Figueiredo Angelo Miguel , Cabrita Eurico J.
Published: September 2014

The influence of imidazolium-IL cations and anions on HSA destabilisation was investigated at atomic detail by a combination of STD-NMR and 35Cl NMR.
How protein structure affects redox reactivity: example of Human centrin 2
Authors: Et Taouil Abdeslam , Brun Emilie , Duchambon Patricia , Blouquit Yves , Gilles Manon , Maisonhaute Emmanuel , Sicard-Roselli Cécile
Published: September 2014

Human centrin 2 is a protein very sensitive to oxidative stress. Protein reactivity is unraveled by gamma radiolysis and electrochemical techniques.
Novel layered crystalline organic polymer-inorganic hybrid material comprising calcium phosphate with unique architectures for superior performance catalyst support
Authors: Huang Jing , Tang Mei , Li Xin , Zhong Guo Zhen , Li Chang Ming
Published: September 2014

Various pores or channels produced by the modification of PS-PVPA chain could contribute to significant impact on the excellent catalytic activity.
Temperature dependent iodide oxidation by MLCT excited states
Authors: Taheri Atefeh , Meyer Gerald J.
Published: September 2014

Temperature dependent excited state iodide oxidation by two heteroleptic Ru polypyridyl compounds was quantified for the first time.
Synthesis, structures, and reactivity of the base-stabilized silanone molybdenum complexes
Authors: Muraoka Takako , Abe Keisuke , Kimura Haruhiko , Haga Youhei , Ueno Keiji , Sunada Yusuke
Published: September 2014

Base-stabilized silanone molybdenum complexes were synthesized by the oxygenation of the MSi bond in the silyl(silylene)molybdenum complex with 1 eq. of PNO in the presence of Lewis base L.
Ca–Ca interaction in inverse sandwich Ca–C8H8–Ca
Authors: Liu Nan-nan , Gao Si-meng , Ding Yi-hong
Published: September 2014

The inverse sandwich Ca–C8H8–Ca is predicted to be open-shell singlet Ca–C8H8–Ca. The singlet diradical character is caused by the C8H8 ligand preventing the spin-paired electrons of different calcium atoms from forming Ca–Ca bonds. A direct Ca–Ca bond is favorable in closed-shell singlet (DME)3Ca–C8H8–Ca(DME)3, because dimethyl ether molecules could push the spin-paired electrons of different calcium atoms to migrate towards the direction of Ca–Ca bonding.
Measuring thermoelectric transport properties of materials
Authors: Borup Kasper A. , de Boor Johannes , Wang Heng , Drymiotis Fivos , Gascoin Franck , Shi Xun , Chen Lidong , Fedorov Mikhail I. , Müller Eckhard , Iversen Bo B. , Snyder G. Jeffrey
Published: September 2014

In this review we discuss considerations regarding the common techniques used for measuring thermoelectric transport properties necessary for calculating the thermoelectric figure of merit, zT.
Evaluation of bioaerosol exposures during hospital bronchoscopy examinations
Authors: Lavoie Jacques , Marchand Geneviève , Cloutier Yves , Hallé Stéphane , Nadeau Sylvie , Duchaine Caroline , Pichette Gilbert
Published: September 2014

During hospital bronchoscopy examinations, aerosols emitted from the patient's during coughing can be found suspended in the ambient air. The aerosols can contain pathogenic microorganisms.
A comparative approach to the most sustainable protocol for the β-azidation of α,β-unsaturated ketones and acids
Authors: Andraos John , Ballerini Eleonora , Vaccaro Luigi
Published: September 2014

In this contribution we have used green metrics analysis to compare the material efficiency, environmental impact, and safety-hazard impact in order to compare flow and batch procedures for azidation of α,β-unsaturated carbonyls.
Trapping particles using waveguide-coupled gold bowtie plasmonic tweezers
Authors: Lin Pin-Tso , Chu Heng-Yi , Lu Tsan-Wen , Lee Po-Tsung
Published: September 2014

Compact plasmonic tweezers on optical waveguides are proposed and demonstrated with a highly enhanced and concentrated field to precisely trap particles with very strong optical forces.
The synthesis of a manganese dioxide–iron oxide–graphene magnetic nanocomposite for enhanced uranium(vi) removal
Authors: Tan Lichao , Wang Jun , Liu Qi , Sun Yanbo , Jing Xiaoyan , Liu Lianhe , Liu Jingyuan , Song Dalei
Published: September 2014

A MnO2–Fe3O4–rGO composite was prepared and exhibited fast and efficient sorption for uranium(vi).
O-Arylation with nitroarenes: metal-catalyzed and metal-free methodologies
Authors: Mondal Manoj , Bharadwaj Saitanya K. , Bora Utpal
Published: September 2014

Emergence of nitroarene as an alternative to aryl halides inO-arylation of arylboronic acid or phenols has been highlighted.
Metal-free, one-pot conversion of proline derivatives into 2-aryl-3-iodo pyrrolidines by a sequential scission–iodination–arylation process
Authors: Batchu Venkateswara Rao , Romero-Estudillo Iván , Boto Alicia , Miguélez Javier
Published: September 2014

A sequential radical decarboxylation–oxidation–iodination–arylation process allows the metal-free, direct conversion of proline derivatives into 2-aryl-3-iodopyrrolidines, which are valuable precursors of a variety of heterocycles.
Trienamines derived from 5-substituted furfurals: remote ε-functionalization of 2,4-dienals
Authors: Coelho Jaime A. S. , Trindade Alexandre F. , André Vânia , Teresa Duarte M. , Veiros Luis F. , Afonso Carlos A. M.
Published: September 2014

The remote selective ε-functionalization of 5-substituted furfurals by trienamine catalysis is described, resulting in a new scaffold.
One molecule of ionic liquid and tert-alcohol on a polystyrene-support as catalysts for efficient nucleophilic substitution including fluorination
Authors: Shinde Sandip S. , Patil Sunil N.
Published: September 2014

The tert-alcohol and ionic liquid solvents in one molecule [mim-tOH][OMs] was immobilized on polystyrene and reported to be a highly efficient catalyst in aliphatic nucleophilic substitution using alkali metal salts.
Synthesis of functionalized fulvenes: [3 + 2] annulation of ethyl α-chlorocyclopropaneformates with 1,3-dicarbonyl compounds
Authors: Zhu Yuequan , Zhang Min , Yuan Hongling , Gong Yuefa
Published: September 2014

An efficient method is reported to produce acidic multi-substituted fulvenes at high yields (up to 94%) through the base-promoted [3 + 2] annulation reaction of ethyl α-chlorocyclopropaneformates with 1,3-dicarbonyl compounds.
Characterization of the binding of the Finland trityl radical with bovine serum albumin
Authors: Song Yuguang , Liu Yangping , Liu Wenbo , Villamena Frederick A. , Zweier Jay L.
Published: September 2014

The Finland trityl radical CT-03 binds to bovine serum albumin, inducing the broadening of its EPR signal.
Determination of diltiazem in the presence of timolol in human serum samples using a nanoFe3O4@GO modified glassy carbon electrode
Authors: Hasanzadeh Mohammad , Pournaghi-Azar Mohammad Hossein , Shadjou Nasrin , Jouyban Abolghasem
Published: September 2014

A new chemically modified electrode was constructed based on a magnetic graphene oxide modified glassy carbon electrode (nanoFe3O4@GO-GC).
Rh-catalyzed WO3 with anomalous humidity dependence of gas sensing characteristics
Authors: Choi Kwon-Il , Hwang Su-Jin , Dai Zhengfei , Chan Kang Yun , Lee Jong-Heun
Published: September 2014

An anomalous humidity dependence of gas sensing characteristics is found for a Rh-loaded WO3 sensor, where the resistance and gas response increased in humid atmospheres.
Inkjet-printed PEDOT:PSS electrodes on plasma-modified PDMS nanocomposites: quantifying plasma treatment hardness
Authors: Chiolerio Alessandro , Rivolo Paola , Porro Samuele , Stassi Stefano , Ricciardi Serena , Mandracci Pietro , Canavese Giancarlo , Bejtka Katarzyna , Pirri Candido Fabrizio
Published: September 2014

The surface of PDMS composites containing copper spiky particles was treated using atmospheric pressure plasma to optimize surface tension for PEDOT:PSS inkjet printed electrodes. Quantitative comparison based on image analysis was done.
Exploiting oriented attachment in stabilizing La3+-doped gallium oxide nano-spindles
Authors: Dar M. Ibrahim , Sampath S. , Shivashankar S. A.
Published: September 2014

The morphology of the single crystalline gallium oxide nano-spindles remained conserved even after doping them with >1.4 at% of La3+ ions and formation of such nanostructures could be explained by invoking the mechanism of oriented attachment.
Mesoporous poly-melamine-formaldehyde stabilized palladium nanoparticle (Pd@mPMF) catalyzed mono and double carbonylation of aryl halides with amines
Authors: Molla Rostam Ali , Iqubal Md. Asif , Ghosh Kajari , Roy Anupam Singha , Kamaluddin Kamaluddin , Islam Sk. Manirul
Published: September 2014

A new mesoporous polymer stabilized Pd nano (mPMF–Pd0) has been synthesized and well characterized. The catalytic performance of this complex has been tested for mono and double carbonylation of aryl halides with amines.
Enalos InSilicoNano platform: an online decision support tool for the design and virtual screening of nanoparticles
Authors: Melagraki Georgia , Afantitis Antreas
Published: September 2014

A QNAR model, available online through Enalos InSilicoNano platform, has been developed and validated for the risk assessment of nanoparticles (NPs).
Synthesis of β-ketoesters from renewable resources and Meldrum's acid
Authors: Brinkerhoff Rafael C. , Tarazona Hernan F. , de Oliveira Patrick M. , Flores Darlene C. , Montes D'Oca Caroline Da R. , Russowsky Dennis , Montes D'Oca Marcelo G.
Published: September 2014

β-Ketoesters are valuable building blocks for the synthesis of compounds with different biological activities.
Origin of blue emission in ThO2 nanorods: exploring it as a host for photoluminescence of Eu3+, Tb3+ and Dy3+
Authors: Gupta Santosh K. , Ghosh P. S. , Arya A. , Natarajan V.
Published: September 2014

Nanorods of ThO2 were synthesized in a reverse micelle technique using cetyl trimethyl ammonium bromide as a surfactant and characterized by X-ray diffraction and transmission electron microscopy.
Serine-based gemini surfactants with different spacer linkages: from self-assembly to DNA compaction
Authors: Silva Sandra G. , Oliveira Isabel S. , do Vale M. Luísa C. , Marques Eduardo F.
Published: September 2014

Cationic serine-based gemini surfactants have strong potential as compaction agents of nucleic acids for efficient non-viral gene delivery.
Enhanced cycle performance of a Li–S battery based on a protected lithium anode
Authors: Ma Guoqiang , Wen Zhaoyin , Wang Qingsong , Shen Chen , Jin Jun , Wu Xiangwei
Published: September 2014

A conductive polymer layer is prepared on the surface of a lithium anode as the protective layer for a Li–S battery.
Enhanced absorbing properties of three-phase composites based on a thermoplastic-ceramic matrix (BaTiO3 + PVDF) and carbon black nanoparticles
Authors: Meng Xiao-Min , Zhang Xiao-Juan , Lu Chang , Pan Ya-Fei , Wang Guang-Sheng
Published: September 2014

Three phase (CB + BT)/PVDF composites with enhanced absorption properties have been synthesized. The results indicate that the maximum reflection loss can reach −38.8 dB at 9.2 GHz; the enhancement mechanism was explained.
Alternated bimetallic [Ru–M] (M = Fe2+, Zn2+) coordination polymers based on [Ru(bpy)3]2+ units connected to bis-terpyridine ligands: synthesis, electrochemistry and photophysics in solution or in thin film on electrodes
Authors: Lombard Jean , Jose D. Amilan , Castillo Carmen E. , Pansu Robert , Chauvin Jérôme , Deronzier Alain , Collomb Marie-Noëlle
Published: September 2014

A [Ru(bpy)3]2+ complex bearing two free terpyridines is used to obtain coordination polymers with photoredox activities.
Optimal scheduling for maintenance period of generating units using a hybrid scatter‐genetic algorithm
Authors: Kim Jinho , Geem Zong Woo
Published: September 2014

Finding an optimal maintenance schedule for generating units and securing the adequate amount of generation availability as a preventive measure to keep the power system reliable is becoming of great importance under the tight operating reserve margin in electricity markets. Therefore most recent research on maintenance scheduling concentrates on how to economically and reliably determine the optimal set of maintenance period for each generating unit while satisfying a variety of constraints given by a system operator. This study presents a methodology for optimal maintenance scheduling of generating units using a hybrid algorithm that combines a scatter search and a genetic algorithm. To verify the effectiveness of the proposed algorithm, a sample test system of 21 units is selected and the results are compared with those of the recent meta‐heuristic algorithms, including genetic algorithms, discrete particle swarm optimisation and modified discrete particle swarm optimisation. This study does a comparison between the proposed method and other conventional ones to determine the maintenance schedule for each generating unit. The proposed method shows a higher performance in the objective function evaluation than the conventional ones, and consequently yields a more optimal solution of the maintenance scheduling problem. The proposed method has also been explored on the IEEE reliability test system, and the results show that the proposed algorithm can provide a robust and consistent performance.
Fabrication of silicon hierarchical nanopillar arrays based on nanosphere lithography
Authors: Su Zongming , Zhang Xiao‐Sheng , Hu Wei , Liu Wen , Han Mengdi , Zhang Haixia
Published: September 2014

A fabrication process of silicon hierarchical nanopillar arrays (NPAs) based on the self‐assembled colloid particle monolayer is presented. Using colloid particles assembled by the evaporation‐induced method as masks, well‐ordered silicon NPAs were fabricated by assessing the deep reactive ion etching process. After the optimisation of the cycles of etching and passivation steps, double‐layer hierarchical NPAs were achieved simultaneously. Systematic analysis and experiments were conducted to investigate the transition from well‐ordered silicon NPAs to silicon hierarchical NPAs. An explanation of this transition is provided based on the collapsing phenomenon discovered in the experiments.
Statistics of the turbulent kinetic energy dissipation rate and its surrogates in a square cylinder wake flow
Authors: Lefeuvre N. , Thiesset F. , Djenidi L. , Antonia R. A.
Published: September 2014

A numerical simulation based on the lattice Boltzmann method is carried out in the wake of a square cylinder with the view to investigating possible surrogates for the instantaneous turbulent kinetic energy dissipation rate, ε, as well as its mean value, \documentclass[12pt]{minimal}\begin{document}$\overline{\epsilon }$\end{document}ε¯. Various surrogate approximations of ε, based on local isotropy (εiso), local axisymmetry along the streamwise direction x (εa, x) and the transverse direction y (εa, y), local homogeneity (εhom), and homogeneity in the transverse plane, (ε4x), are assessed. All the approximations are in agreement with \documentclass[12pt]{minimal}\begin{document}$\overline{\epsilon }$\end{document}ε¯ when the distance downstream of the obstacle is larger than about 40 diameters. Closer to the obstacle, the agreement remains reasonable only for \documentclass[12pt]{minimal}\begin{document}$\overline{\epsilon }_{a,x}$\end{document}ε¯a,x, \documentclass[12pt]{minimal}\begin{document}$\overline{\epsilon }_{hom}$\end{document}ε¯hom and \documentclass[12pt]{minimal}\begin{document}$\overline{\epsilon }_{4x}$\end{document}ε¯4x. The probability density functions (PDF) and joint PDFs of ε and its surrogates show that ε4x correlates best with ε while εiso and εhom present the smallest correlation. The results indicate that ε4x is a very good surrogate for ε and can be used for correctly determining the behaviour of ε.
Helium droplet calorimetry of strongly bound species: Carbon clusters from C2 to C12
Authors: Lewis William K. , Harruff-Miller Barbara A. , Leatherman Peter , Gord Michael A. , Bunker Christopher E.
Published: September 2014

Helium droplet beam methods are a versatile technique that can be used to assemble a wide variety of atomic and molecular clusters. In recent years, methods have been developed to utilize helium droplets as nano-calorimeters to measure the binding energies of weakly bound complexes assembled within the droplet. In the current investigation we extend the helium droplet calorimetry approach to the study of a very strongly bound system: carbon clusters which are bound by several eV per atom. We utilize laser heating of bulk carbon samples to dope the helium droplets with evaporated carbon species. Depending on the laser target, the vaporization plume is found to consist primarily of C3 alone or C2 and C3. These species are sequentially captured by the droplet and assembled into larger carbon clusters in a stepwise manner. The assembled Cn clusters are detected via mass spectrometry of the doped droplets and the droplet sizes required to detect the various carbon clusters observed are used to estimate the reaction energies of the associated assembly pathways. The helium droplet data qualitatively reflect the trends in assembly energetics, but at first glance appear to yield energies that differ dramatically from theoretical values. Statistical modeling of the helium droplet calorimetry experiment reconciles the differences quantitatively. Our modeling also generates a calibration curve that relates the assembly/reaction energy and threshold mean droplet size over a range of energies from van der Waals interactions to chemical bonding, enabling helium droplet calorimetry methods to be applied quantitatively to a large number of systems.
Double aromaticity in transition metal centered double-ring boron clusters M@B2n (M = Ti, Cr, Fe, Ni, Zn; n = 6, 7, 8)
Authors: Xu Chang , Cheng Longjiu , Yang Jinlong
Published: September 2014

It is well known that double-ring boron clusters have got the special double aromaticity with delocalized π orbitals in two directions (tangential and radial), which are potential ligands centered by a transition metal. In this article, the transition metal centered double-ring boron clusters M@B2n (M = Ti, Cr, Fe, Ni, Zn; n = 6, 7, 8) are theoretically investigated by density functional theory calculations. These endohedral compounds have also got double aromaticity in both tangential and radial directions. Interestingly, the tangential delocalized π orbitals of boron ligands following the Huckle's (4n + 2) rule do not interact with the central metal, while the radial π orbitals of boron ligands are bonded with the central mental to form spd-π endohedral bonding. The spd-π endohedral bonding follows the 18e-principle in Ni@B14 and Fe@B16. However, due to the flat shape of the compounds, 14e (Cr@B14) and 16e (Ni@B12) can also be electronically very stable where the energy levels of the spd-π orbitals delocalized in z-direction rise up. This intriguing bonding model makes sense in further study of the boron chemistry.
Elastic differential cross sections for C4F6 isomers in the 1.5–200 eV energy electron impact: Similarities with six fluorine containing molecules and evidence of F-atom like scattering
Authors: Hoshino M. , Limão-Vieira P. , Anzai K. , Kato H. , Cho H. , Mogi D. , Tanioka T. , Ferreira da Silva F. , Almeida D. , Blanco F. , García G. , Ingólfsson O. , Tanaka H.
Published: September 2014

We report absolute elastic differential cross sections for electron interactions with the C4F6 isomers, hexafluoro-1,3-butadiene (1,3-C4F6), hexafluoro-2-butyne (2-C4F6), and hexafluorocyclobutene (c-C4F6). The incident electron energy range is 1.5–200 eV, and the scattered electron angular range for the differential measurements varies from 15° to 150°. In all cases the absolute scale of the differential cross section was set using the relative flow technique, with helium as the reference species. Atomic-like behaviour in these scattering systems is shown here for the first time, and is further investigated by comparing the elastic cross sections for the C4F6 isomers with other fluorinated molecules, such as SF6 and CnF6 (n = 2, 3, and 6). We note that for all the six-F containing molecules, the scattering process for electron energies above 30 eV is indistinguishable. Finally, we report results for calculations of elastic differential cross sections for electron scattering from each of these isomers, within an optical potential method and assuming a screened corrected independent atom representation. The level of agreement between these calculations and our measurements is found to be quite remarkable in all cases.
Spatial separation of spoof surface acoustic waves on the graded groove grating
Authors: Jia Han , Lu Minghui , Ni Xu , Bao Ming , Li Xiaodong
Published: September 2014

In this paper, a rigid surface decorated with an array of grooves with graded widths is proposed to get spatial separation of the spoof surface acoustic waves. Because of the intermodal coupling between forward and backward modes on the graded structure, the spoof surface acoustic waves with different frequencies stop propagating ahead and reflect back at different positions of the graded groove grating. The intensity of acoustic field is effectively enhanced near the propagation-stop position due to the slow group velocity. We believe that such system with the capability of energy concentration and wave spatial arrangement by frequencies has potential applications in acoustic wave coupling and absorption.
Formation of suspended bilayer lipid membrane between electrowetting-driven encapsulated droplets
Authors: Fan Shih-Kang , Chen Ching-Wen , Lin Yi-Ying , Chen Li-Chi , Tseng Fan-Gang , Pan Rong-Long
Published: September 2014

Using limited lipid molecules held by two water-core/oil-shell encapsulated droplets, we formed an optically observable bilayer lipid membrane (BLM) across a microfabricated aperture whose dimension was precisely determined and easily scalable. For the minute volume of a 0.1 μL oil (n-decane) shell encapsulating a 1.5 μL water core droplet, only 0.2 to 2.8 nmol or 0.17 to 2.4 μg lipid was required. Microscopes and electrophysiological measurements were performed on the parallel-plate device with three major steps demonstrated: (1) manipulating self-assembled lipid monolayers at the water-oil interface of the encapsulated droplets by electrowetting-on-dielectric (EWOD), (2) forming a BLM by bringing two lipid monolayers towards the aperture and thinning down the oil film between them by Young-Laplace pressure, and (3) incorporating membrane-bound nanopores, α-hemolysin (αHL), on the BLM. This study shows the influence of the lipid concentration to the interfacial tension and EWOD. Plateau-Gibbs border and black membrane area of the BLM were optically observed, while trans-membrane electrophysiological signals were electrically recorded from a pair of Ag/AgCl electrodes.
Correlated inter-grain switching in polycrystalline ferroelectric thin films
Authors: Jing Y. , Leach S. , García R. E. , Blendell J. E.
Published: September 2014

Ferroelectric domain switching within individual nanoscale grains of a 100 nm thick polycrystalline PbZr0.2Ti0.8O3 thin film has been shown to depend on the relative crystallographic orientation of the adjacent grains. Using Piezoresponse Force Microscopy, the significance of local microstructure on the domain switching was demonstrated. Different regions within grains show different coercive fields under the same external electric field. In addition, neighboring grains also show a collective switching pattern, facilitating/suppressing switching on both sides of the grain boundaries compared to the center of the grain. These experimental observations were supported by numerical simulation demonstrating that changing the crystallographic orientation of a grain affects the switching loop of the neighboring grains. Based on both experimental and numerical simulation, the conclusion can be made that microstructural modulation of the local electric and stress field can significantly affect individual grain switching in polycrystalline thin films.
InAs/InAs1−xSbx type-II superlattices for high performance long wavelength infrared detection
Authors: Haddadi A. , Chen G. , Chevallier R. , Hoang A. M. , Razeghi M.
Published: September 2014

High performance long-wavelength infrared nBn photodetectors based on InAs/InAs1−xSbx type-II superlattices on GaSb substrate have been demonstrated. The photodetector's 50% cut-off wavelength was ∼10 μm at 77 K. The photodetector with a 6 μm-thick absorption region exhibited a peak responsivity of 4.47 A/W at 7.9 μm, corresponding to a quantum efficiency of 54% at −90 mV bias voltage under front-side illumination and without any anti-reflection coating. With an R × A of 119 Ω·cm2 and a dark current density of 4.4 × 10−4 A/cm2 under −90 mV applied bias at 77 K, the photodetector exhibited a specific detectivity of 2.8 × 1011 cm. Hz/W.
Logic-memory device of a mechanical resonator
Authors: Yao Atsushi , Hikihara Takashi
Published: September 2014

We report multifunctional operation based on the nonlinear dynamics in a single microelectromechanical system (MEMS) resonator. This letter focuses on a logic-memory device that uses a closed loop control and a nonlinear MEMS resonator in which multiple states coexist. To obtain both logic and memory operations in a MEMS resonator, we examine the nonlinear dynamics with and without control input. Based on both experiments and numerical simulations, we develop a device that combines an OR gate and memory functions in a single MEMS resonator.
A compact relativistic backward-wave oscillator with metallized plastic components
Authors: Ge Xingjun , Zhang Jun , Zhong Huihuang , Qian Baoliang
Published: September 2014

This letter presents the mechanism and realization of a compact relativistic backward-wave oscillator with metallized plastic components. The physical idea, specific structure, and the main testing results are presented. The three periods slow-wave structures with both inner and outer ripples and the coaxial extractor are designed to reduce the volume and increase the efficiency of the device. The metallized plastic components replacing the stainless steel components in the high power microwave (HPM) sources are put forward to reduce the device weight. In the initial experiment, a microwave with frequency of 1.54 GHz, power of 1.97 GW, efficiency of 33.5%, and pulse duration above 47 ns is generated, which proves that this technical route is feasible. Undoubtedly, the technical route can provide a guide to design other types of HPM sources and be benefit to the practical application of the compact HPM systems.
Improved broadband antireflection in Schottky-like junction of conformal Al-doped ZnO layer on chemically textured Si surfaces
Authors: Saini C. P. , Barman A. , Kumar M. , Sahoo P. K. , Som T. , Kanjilal A.
Published: September 2014

Chemically textured Si with improved absorption in the complete range of solar spectrum is investigated by ultraviolet/visible/near-infrared (UV/Vis/NIR) spectroscopy, showing an average specular reflectance of ∼0.4% in the wavelength of 500–3000 nm. The pyramidal structures on such solar-blind Si can reduce the reflectance further below 0.1% in the UV region by conformal growth of granular Al-doped ZnO (AZO) films. X-ray diffraction analyses suggest the growth of polycrystalline AZO on faceted-Si. Moreover, marginal increase in electrical conductivity of AZO is found on textured surfaces, whereas rise in leakage current in Schottky-like Ag/AZO/Si/Ag heterostructure devices is noticed with increasing Si surface area.
Methane conversion in surface- and volume-type dielectric barrier discharges generated in the presence of metal-mesh electrodes
Authors: Kobayashi Kazunobu , Kulinich S. A. , Ito Tsuyohito
Published: September 2014

Methane gas conversion was studied in customized flow-type reactors with different dielectric barrier discharge generated in Ar-CH4-O2 gas mixtures. Different reactor geometries (with either volume or surface-type discharges) and different electrode materials were compared, and gas temperatures during methane conversion processes were evaluated. The discharge was generated by applying either a conventional sinusoid or nanosecond-pulsed voltage. The methane conversion rate was as high as ∼99% with the total gas flow rate of 15 sccm, while the temperatures did not exceed 450 K. No significant effect of electrode material (stainless steel, aluminum, or CuO coated copper) was found, confirming that the conversion temperatures were much lower than those required for activity of typical catalysts. The reactor geometry, flow rate, and oxygen amount could be used to govern both the methane conversion rate and the fractions of components in the final product.
The effect of polarity and surface states on the Fermi level at III-nitride surfaces
Authors: Reddy Pramod , Bryan Isaac , Bryan Zachary , Guo Wei , Hussey Lindsay , Collazo Ramon , Sitar Zlatko
Published: September 2014

Surface states and their influence on the Fermi level at the surface of GaN and AlN are studied using x-ray photoelectron spectroscopy (XPS). The effect of polarity on surface electronic properties was studied. Accurate modeling of the valence band edge and comparison with XPS data revealed the presence of donor surface states at 1.4 eV and acceptor states at energies >2.7 eV from the valence band in GaN. Al polar AlN showed acceptor states at energies >3.3 eV. Density of acceptor surface states was estimated to be between 1013 and 1014 eV−1 cm−2 in both GaN and AlN. The shift in charge neutrality levels and barrier heights due to polarity and the density of surface states on AlN and GaN were estimated from XPS measurements. Theoretical modeling and comparison with XPS data implied full compensation of spontaneous polarization charge by charged surface states. Barrier height measurements also reveal a dependence on polarity with ϕmetal-polar > ϕnon-polar > ϕnitrogen-polar suggesting that the N-polar surface is the most suitable for Ohmic contacts.
Investigation of reactor neutron irradiation induced dark signals increase in COTS array CCDs
Authors: Wang Zujun , Guo Hongxia , Wenshou Zhang , Luo Tongding , Huang Shaoyan , Tang Benqi , Jin Junshan
Published: September 2014

The experiments of reactor neutron irradiation which induce dark signal increase in COTS array CCDs are presented. The flux of the reactor neutron beams was about 1.33 × 108 n/cm2s. The three samples were exposed to 1MeV neutron-equivalent fluences of 1 × 1011, 5 × 1011, and 1 × 1012 n/cm2, respectively. The mean dark signal (KD), dark signal non-uniformity (DSNU), and dark signal spikes (hot pixels) versus neutron fluence are investigated. The degradation mechanisms of the dark signal in CCDs are analyzed. The mean dark signal increase due to neutron displacement damage appears to be proportional to displacement damage dose. The dark images from the CCDs irradiated by neutrons are presented to investigate the generation of dark signal spike. The 1D and 2D figures which show the output signal voltage of pixels in dark images irradiated by different neutron beam fluences, are presented to compare the degradation of KD, DSNU, and dark signal spike.
High quantum efficiency ultrananocrystalline diamond photocathode for photoinjector applications
Authors: Pérez Quintero Kenneth J. , Antipov Sergey , Sumant Anirudha V. , Jing Chunguang , Baryshev Sergey V.
Published: September 2014

We report results of quantum efficiency (QE) measurements carried out on a 150 nm thick nitrogen-incorporated ultrananocrystalline diamond terminated with hydrogen; abbreviated as (N)UNCD:H. (N)UNCD:H demonstrated a remarkable QE of ∼10−3 (∼0.1%) at 254 nm. Moreover, (N)UNCD:H was sensitive in visible light with a QE of ∼5 × 10−8 at 405 nm and ∼5 × 10−9 at 436 nm. Importantly, after growth and prior to QE measurements, samples were exposed to air for about 2 h for transfer and loading. Such design takes advantage of a key combination: (1) H-termination proven to induce negative electron affinity on the (N)UNCD and to stabilize its surface against air exposure; and (2) N-incorporation inducing n-type conductivity in intrinsically insulating UNCD.
Photosensitive hole transport in Schottky-contacted Si nanomembranes
Authors: Feng Ping , Wu Guodong , Schmidt Oliver G. , Mei Yongfeng
Published: September 2014

When Schottky-contacted Si nanomembranes (SiNMs; 27 nm in thickness) are exposed to light it is mainly the hole transport responding sensitively to the illumination. The electron transport on the contrary remains rather unaffected by the exposure, which cannot be explained by a simple creation of electron-hole pairs. We attribute this effect to the holes activated from SiNM surfaces, which strongly supports the existence of surface doping in SiNMs [P. P. Zhang, E. Tevaarwerk, B. N. Park, D. E. Savage, G. K. Celler, I. Knezevic, P. G. Evans, M. A. Eriksson, and M. G. Lagally, Nature 439, 703–706 (2006)]. Our work suggests that the surfaces play a decisive role when creating and designing optoelectronic devices based on SiNMs.
The pivotal role of SiO formation in the migration and Ostwald ripening of Ge quantum dots
Authors: Chen K. H. , Wang C. C. , George T. , Li P. W.
Published: September 2014

We report a unique, cooperative mechanism that involves the interplay of Ge, Si, and Oxygen interstitials enabling an unusual Ostwald ripening and migration behavior of Ge nanocrystallites and quantum dots (QDs) embedded within a SiO2 matrix. In the presence of high Si interstitial fluxes with no supply of oxygen interstitials, the oxide surrounding the Ge QDs is decomposed by the Si interstitials, creating the volatile SiO reaction product and hence voids that enable the Ge QDs to grow by Ostwald ripening. When both Si and Oxygen interstitials are present in high concentrations, the Ostwald ripened Ge QD is further able to migrate towards the source of the Si interstitials. The QD movement occurs by virtue of the fact that the SiO created in front of the QD combines with O interstitials to regenerate SiO2 behind the Ge QD on its migration path. Thus, SiO influences the migration and Ostwald ripening behavior of the Ge QDs via a unique “Destruction-Construction” mechanism.
Plan-view transmission electron microscopy investigation of GaAs/(In,Ga)As core-shell nanowires
Authors: Grandal Javier , Wu Mingjian , Kong Xiang , Hanke Michael , Dimakis Emmanouil , Geelhaar Lutz , Riechert Henning , Trampert Achim
Published: September 2014

Plan-view transmission electron microscopy in combination with electron energy-loss spectroscopy have been used to analyze the strain and the chemical composition of GaAs/(In,Ga)As core-shell nanowires. The samples consist of an GaAs core and a radially arranged (In,Ga)As layer as quantum well and GaAs outer-shell. The nominal parameters of the quantum well in the two samples under investigation are: an indium concentration of 25% and a quantum well thickness of 22 nm and 11 nm, respectively, while the core and the external shell dimensions are fixed. Scanning transmission electron microscopy using high-angle annular dark field detector was performed to verify the actual dimensions of the layers. Geometric phase analysis was carried out in order to examine the local strain of the radial (In,Ga)As quantum well, while the local chemical composition was determined by means of spatially resolved electron energy-loss spectroscopy. Finite elements calculations were carried out in order to simulate the multi-shell structure and extract the actual strain distribution. The results indicate that there is a uniform strain distribution at the coherent interfaces. In addition, based on calculations, we show that there is no region in the considered core-shell structure absolutely free of strain.
High superionic conduction arising from aligned large lamellae and large figure of merit in bulk Cu1.94Al0.02Se
Authors: Zhong Bin , Zhang Yong , Li Weiqian , Chen Zhenrui , Cui Jingying , Li Wei , Xie Yuandong , Hao Qing , He Qinyu
Published: September 2014

Good thermoelectric materials should have low thermal conductivity, high electrical conductivity, and Seebeck coefficient, which cannot be easily balanced in bulk materials. Exceptionally, the super-ionics in β-Cu2Se can favorably contribute large ionic electrical conductivity and a liquid-like thermal conductivity by Cu+ ions. In the previous work, the superionic mechanism was found to be enhanced by small and randomly orientated lamellae with alternating ordered Se ion monolayer and disordered Cu ion bilayers. Here, we further enhance the superionic mechanism by increasing and better aligning lamellae in bulk Cu1.94Al0.02Se, resulting in a large thermoelectric figure of merit of 2.62 at 756 °C.
The value of research: using the Impact Tool to evaluate realised and anticipated benefits of the Cooperative Research Centre for Beef Genetic Technologies
Authors: Griffith G. R. , Burrow H. M.
Published: September 2014

The Cooperative Research Centre (CRC) for Beef Genetic Technologies operated for its third successive 7-year term from July 2005 to June 2012. It developed new genetic and genomic technologies and non-genetic ‘products’ (practices, processes, tools and technologies) to improve profitability, productivity, animal welfare and responsible resource use of Australian beef businesses. In this paper we assess how well the third-term Beef CRC met its objectives, at the end of its funding period, using the Impact Tool software package developed by the CRC Program of the Commonwealth Government. The Impact Tool generates two commonly used measures of return on investment: the net present value (NPV) and the benefit : cost ratio (BCR). The NPV, the sum of discounted benefits minus the sum of discounted costs, was $233.2 m, when evaluated over the period 2005/06–2020/21. The BCR, the sum of discounted benefits divided by the sum of discounted costs, was 2.94, over the same period. Thus on both measures, investing in the Beef CRC is expected to have been profitable. We conclude by noting that the value of the Impact Tool is not only for ex-ante and ex-post evaluation of the impacts of particular technologies, but it also provides a very effective tool for RD&E project planning.
Complementary symbiont contributions to plant decomposition in a fungus-farming termite
Authors: Poulsen Michael , Hu Haofu , Li Cai , Chen Zhensheng , Xu Luohao , Otani Saria , Nygaard Sanne , Nobre Tania , Klaubauf Sylvia , Schindler Philipp M. , Hauser Frank , Pan Hailin , Yang Zhikai , Sonnenberg Anton S. M. , de Beer Z. Wilhelm , Zhang Yong , Wingfield Michael J. , Grimmelikhuijzen Cornelis J. P. , de Vries Ronald P. , Korb Judith , Aanen Duur K. , Wang Jun , Boomsma Jacobus J. , Zhang Guojie
Published: September 2014

Significance

Old World (sub)tropical fungus-growing termites owe their massive ecological footprints to an advanced symbiosis with
Termitomyces
fungi. They also have abundant gut bacteria, but the complementarity roles of these symbionts have remained unclear. We analyzed the genomic potential for biomass decomposition in a farming termite, its fungal symbiont, and its bacterial gut communities. We found that plant biomass conversion is mostly a multistage complementary cooperation between
Termitomyces
and gut bacteria, with termite farmers primarily providing the gut compartments, foraging, and nest building. A mature queen had highly reduced gut microbial diversity for decomposition enzymes, suggesting she had an exclusively fungal diet even though she may have been the source of the gut microbes of the colony’s first workers and soldiers.
Mechanochemical actuators of embryonic epithelial contractility
Authors: Kim YongTae , Hazar Melis , Vijayraghavan Deepthi S. , Song Jiho , Jackson Timothy R. , Joshi Sagar D. , Messner William C. , Davidson Lance A. , LeDuc Philip R.
Published: September 2014

Significance

This study shows how cell contractility is triggered within an embryonic epithelial sheet by local ligand stimulation and coordinates a long-range contraction response. The stimulation–response circuit exposed here provides a better understanding of how morphogenetic processes integrate responses to stimulation and how intercellular responses are transmitted across multiple cells. Understanding the systems-level behavior of biological signaling networks may allow us to control biological actuators with engineered spatiotemporal stimulation. Our findings will provide a better understanding of contractility-dependent morphogenetic movements as well as the intercellular communication pathways critical during developmental biology, synthetic morphogenesis, and multicellular mechanotransduction signaling.
Beat synchronization predicts neural speech encoding and reading readiness in preschoolers
Authors: Woodruff Carr Kali , White-Schwoch Travis , Tierney Adam T. , Strait Dana L. , Kraus Nina
Published: September 2014

Significance

Sensitivity to fine timing cues in speech is thought to play a key role in language learning, facilitating the development of phonological processing. In fact, a link between beat synchronization, which requires fine auditory–motor synchrony, and language skills has been found in school-aged children, as well as adults. Here, we show this relationship between beat entrainment and language metrics in preschoolers and use beat synchronization ability to predict the precision of neural encoding of speech syllables in these emergent readers. By establishing links between beat keeping, neural precision, and reading readiness, our results provide an integrated framework that offers insights into the preparative biology of reading.
Scaling description of the yielding transition in soft amorphous solids at zero temperature
Authors: Lin Jie , Lerner Edan , Rosso Alberto , Wyart Matthieu
Published: September 2014

Significance

Yield stress solids flow if a sufficiently large shear stress is applied. Although such materials are ubiquitous and relevant for industry, there is no accepted microscopic description of how they yield. Here we propose a scaling description of the yielding transition that relates the flow curve, the statistics of the avalanches of plasticity observed at threshold, and the density of local zones that are about to yield. Our description shares some similarity with the depinning transition that occurs when an elastic manifold is driven through a random potential, but also presents some striking differences. Numerical simulations on a simple elasto-plastic model find good agreement with our predictions.
Conifer species adapt to low-rainfall climates by following one of two divergent pathways
Authors: Brodribb Timothy J. , McAdam Scott A.M. , Jordan Gregory J. , Martins Samuel C.V.
Published: September 2014

Significance

A major determinant of plant species distribution on Earth is a specific tolerance to soil drying, yet there are currently no functional or anatomical characteristics that can predict species’ requirement for rainfall. This study examines the systems responsible for controlling water delivery and water loss in the leaves of conifers and finds functional evidence of how conifers have evolved in drying climates over the course of the last 150 million years. Two “strategies” for conserving water during water stress emerged. One group relied on the plant hormone abscisic acid to maintain stomata closed during sustained drought, and another, more derived group allowed leaves to dehydrate and resisted damage by producing a water transport system capable of functioning under the extreme tension that develops in water-stressed plants.
Resolvin D1 limits 5-lipoxygenase nuclear localization and leukotriene B
4
synthesis by inhibiting a calcium-activated kinase pathway
Authors: Fredman Gabrielle , Ozcan Lale , Spolitu Stefano , Hellmann Jason , Spite Matthew , Backs Johannes , Tabas Ira
Published: September 2014

Significance

Specialized proresolving mediators, such as resolvin D1 (RvD1), are endogenous molecules that both dampen inflammation without compromising host defense and promote tissue resolution. A prime example is RvD1’s ability to decrease the ratio of proinflammatory leukotriene B
4
(LTB
4
) to proresolving lipoxin A
4
(LXA
4
), but the mechanism is not known. We have discovered a new calcium kinase signaling pathway through which RvD1 lowers the nuclear:cytoplasmic ratio of 5-lipoxygenase (5-LOX), the common enzyme for LTB
4
and LXA
4
biosynthesis This shift in 5-LOX localization dampens LTB
4
production and enhances LXA
4
production. By providing a new mechanistic understanding of how RvD1 tempers inflammation to facilitate resolution, these findings can help devise new therapeutic strategies for diseases driven by nonresolving inflammation.
Ribosome-induced tuning of GTP hydrolysis by a translational GTPase
Authors: Maracci Cristina , Peske Frank , Dannies Ev , Pohl Corinna , Rodnina Marina V.
Published: September 2014

Significance

Translational elongation factor Tu (EF-Tu) utilizes GTP hydrolysis to control the speed and fidelity of decoding. We explored the reaction coordinate for GTP hydrolysis by EF-Tu and the origins of the million-fold activation effect of the ribosome. We show that amino acid residues in the P loop (Asp21) and switch II region (His84) are key to catalysis of GTP hydrolysis on the ribosome but are not essential for the intrinsic GTPase of EF-Tu. We conclude that the ribosome contributes to catalysis indirectly, by inducing a conformation that provides an electrostatic stabilization of the transition state. Translational GTPases provide yet another example of how the ribosome, an ancient RNA-based catalyst, solves problems posed by the limited catalytic power of RNA.
Transformation of quiescent adult oligodendrocyte precursor cells into malignant glioma through a multistep reactivation process
Authors: Galvao Rui Pedro , Kasina Anita , McNeill Robert S. , Harbin Jordan E. , Foreman Oded , Verhaak Roel G. W. , Nishiyama Akiko , Miller C. Ryan , Zong Hui
Published: September 2014

Significance

How malignant gliomas arise in a mature brain remains a mystery, which hinders the development of effective treatments. Which cell types can escape their quiescent, adult state and how they do so is unknown. Additionally, because gliomas are only detected at advanced stages, the full course of transformation remains uncharacterized. Here we report that adult oligodendrocyte precursor cells, despite their relatively quiescent properties, can be reactivated to a highly proliferative state by
p53
and
NF1
mutations and give rise to malignant gliomas. Furthermore, we describe the early phase of gliomagenesis for the first time, revealing a multistep process of reactivation, dormancy, and final transformation in which mammalian target of rapamycin signaling plays a critical role at both early and late steps.