bluuebunny/crossref_metadata_2025 huggingface dataset:
NIR provides excellent predictions of properties of biocoal from torrefaction and pyrolysis of biomass
Authors: Lestander Torbjörn A. , Rudolfsson Magnus , Pommer Linda , Nordin Anders
Published: October 2014

NIR spectrometry combined with multivariate calibration modeling has potential utility as a standardized method for rapidly characterising thermotreated biomass predictions with respect of its energy, carbon, oxygen, hydrogen, ash, volatile matter and fixed carbon contents.
Exploration of interactions between membrane proteins embedded in supported lipid bilayers and their antibodies by reflectometric interference spectroscopy-based sensing
Authors: Kurihara Yoshikazu , Sawazumi Tsuneo , Takeuchi Toshifumi
Published: October 2014

A microfluidic reflectometric interference spectroscopy (RIfS)-based sensor was fabricated to investigate the activity of multidrug resistance-associated protein 1 (MRP1), applied as a model membrane protein.
A facile single crystal to single crystal transition with significant structural contraction on desolvation
Authors: Knichal Jane V. , Gee William J. , Burrows Andrew D. , Raithby Paul R. , Teat Simon J. , Wilson Chick C.
Published: October 2014

Ladder network, [Pb(ebdc)(MeOH)]2·H2O, undergoes a facile SCSC transformation to yield [Pb(ebdc)] with a 20% contraction of the crystallographicbaxis.
Polyhierarchically structured TiP2O7/C microparticles with enhanced electrochemical performance for lithium-ion batteries
Authors: Sun Yanru , Gai Ligang , Zhou Yan , Zuo Xinzhu , Zhou Jianhua , Jiang Haihui
Published: October 2014

Polyhierarchically structured TiP2O7/C microparticles constructed by carbon-coated nanoflakes enchasing crystalline nanoparticles have been prepared and been found to show enhanced electrochemical performance due to the hierarchical architecture with carbon nano-coating and 3D open pores.
Feasibility study of the Mn–Na2WO4/SiO2 catalytic system for the oxidative coupling of methane in a fluidized-bed reactor
Authors: Sadjadi S. , Jašo S. , Godini H. R. , Arndt S. , Wollgarten M. , Blume R. , Görke O. , Schomäcker R. , Wozny G. , Simon U.
Published: October 2014

The catalytic system Mn–Na2WO4/SiO2, was studied in a miniplant fluidized-bed reactor for oxidative coupling of methane.
Reactive removal of surface oxygen by H2, CO and CO/H2 on a Au/CeO2 catalyst and its relevance to the preferential CO oxidation (PROX) and reverse water gas shift (RWGS) reaction
Authors: Wang L. C. , Widmann D. , Behm R. J.
Published: October 2014

CO and H2 compete for the same active surface (lattice) oxygen species, but with a much lower reduction efficiency of H2 compared to CO and CO–H2 mixtures, during removal of active oxygen from a Au/CeO2 catalyst by H2, CO or CO/H2 at temperatures between 30 and 300 °C.
Unraveling the origins of catalyst degradation in non-heme iron-based alkane oxidation
Authors: Grau Michaela , Kyriacou Andrew , Cabedo Martinez Fernando , de Wispelaere Irene M. , White Andrew J. P. , Britovsek George J. P.
Published: October 2014

A series of iron(ii) complexes with tetradentate and pentadentate pyridyl amine ligands has been used for the oxidation of cyclohexane with hydrogen peroxide. Ligand degradation is observed under oxidising conditions via oxidative N-dealkylation.
High nitrogen-doped carbon/Mn3O4hybrids synthesized from nitrogen-rich coordination polymer particles as supercapacitor electrodes
Authors: Wang Kuaibing , Shi Xiaobo , Lu Aiming , Ma Xiaoyan , Zhang Zhiyang , Lu Yanan , Wang Hongju
Published: October 2014

High N-doped C/Mn3O4composites are charged and discharged faster and have higher capacitance than C/Mn3O4nanostructures with low N-amounts with 96% retained capacitance after 500 cycles at a constant current.
Functional links between Pt single crystal morphology and nanoparticles with different size and shape: the oxygen reduction reaction case
Authors: Li Dongguo , Wang Chao , Strmcnik Dusan S. , Tripkovic Dusan V. , Sun Xiaolian , Kang Yijin , Chi Miaofang , Snyder Joshua D. , van der Vliet Dennis , Tsai Yifen , Stamenkovic Vojislav R. , Sun Shouheng , Markovic Nenad M.
Published: October 2014

Design of active and stable Pt-based nanoscale electrocatalysts for the oxygen reduction reaction (ORR).
Tunable reverse electrodialysis microplatform with geometrically controlled self-assembled nanoparticle network
Authors: Choi Eunpyo , Kwon Kilsung , Kim Daejoong , Park Jungyul
Published: October 2014

In this paper, an efficient microplatform based on reverse electrodialysis, which enables high ionic flux through three dimensional nanochannel networks for high power energy generation, is demonstrated.
Solid phase extraction of doxorubicin using molecularly imprinted polymer coated magnetite nanospheres prior to its spectrofluorometric determination
Authors: Ahmadi Mazaher , Madrakian Tayyebeh , Afkhami Abbas
Published: October 2014

Selective doxorubicin-imprinted polymer coated magnetite nanospheres were synthesized.
Mechanistic studies on the indole prenyltransferases
Authors: Tanner Martin E.
Published: October 2014

This review article presents a review of recent mechanistic studies on the reactions catalyzed by the soluble indole prenyltransferases.
Crystalline phosphorus fibers: controllable synthesis and visible-light-driven photocatalytic activity
Authors: Shen Zhurui , Hu Zhuofeng , Wang Wanjun , Lee Siu-Fung , Chan Donald K. L. , Li Yecheng , Gu Ting , Yu Jimmy C.
Published: October 2014

Micron- and submicron-sized photocatalytic single crystalline phosphorus fibers are prepared from amorphous commercial red phosphorus by a simple CVD method.
Synthesis of fully functionalized aglycone of lycoperdinoside A and B
Authors: Chandrasekhar Balla , Athe Sudhakar , Reddy P. Purushotham , Ghosh Subhash
Published: October 2014

Synthesis of fully functionalized aglycone of lycoperdinoside A and B is achieved via Pd-catalyzed Stille–Migita cross coupling and Evans syn- and anti aldol reactions as key steps.
Thiol-assisted one-pot synthesis of peptide/protein C-terminal thioacids from peptide/protein hydrazides at neutral conditions
Authors: Chen Chenchen , Huang Yichao , Xu Ling , Zheng Yong , Xu Huajian , Guo Qingxiang , Tian Changlin , Li Yiming , Shi Jing
Published: October 2014

An efficient thiol-assisted one-pot synthesis of peptide/protein C-terminal thioacids was achieved by using peptide/protein hydrazides precursors at neutral pH and room temperature (about 20 °C).
Synthesis of polymeric janus nanoparticles and their application in surfactant-free emulsion polymerizations
Authors: Pham Binh T. T. , Such Chris H. , Hawkett Brian S.
Published: October 2014

RAFT mediated emulsion polymerization to synthesize Janus nanoparticles and their application to control outcomes in surfactant-free emulsion polymerization.
A review on sludge conditioning by sludge pre-treatment with a focus on advanced oxidation
Authors: Zhou Xu , Jiang Guangming , Wang Qilin , Yuan Zhiguo
Published: October 2014

The production of excess sludge by biological wastewater treatment processes has been a serious issue for the operation of wastewater treatment plants (WWTP) on both the economic and environmental sides.
New solution processed bulk-heterojunction organic solar cells based on a triazine-bridged porphyrin dyad as electron donor
Authors: Sharma Ganesh D. , Zervaki Galateia E. , Angaridis Panagiotis , Coutsolelos Athanassios G.
Published: October 2014

An unsymmetrical porphyrin dyad (ZnP)-[triazine-Npip]-(ZnPCOOH) consisting of two zinc-porphyrin units covalently linked to a peridine-containing triazine group has been used with PC71BM as electron donor and acceptor, respectively, for the active layer of solution-processed BHJ organic solar cells.
Corrosion and wear resistance of 32CrMoV13 steel nitrided by plasma
Authors: Belahssen Okba , Chala Abdelouahed , Ben Temam Hachemi , Benramache Said
Published: October 2014

This paper presents corrosion and wear behavior of the plasma-nitrided 32CrMoV13 steel.
Mechanism studies of LiFePO4cathode material: lithiation/delithiation process, electrochemical modification and synthetic reaction
Authors: Yu Feng , Zhang Lili , Li Yingchun , An Yongxin , Zhu Mingyuan , Dai Bin
Published: October 2014

Olivine-structured lithium ion phosphate (LiFePO4) is one of the most competitive candidates for fabricating energy-driven cathode material for sustainable lithium ion battery (LIB) systems.
Photoaffinity labeling of transcription factors by DNA-templated crosslinking
Authors: Liu Ying , Zheng Wenlu , Zhang Wan , Chen Nan , Liu Yang , Chen Li , Zhou Xiaozhou , Chen Xingshuo , Zheng Haifeng , Li Xiaoyu
Published: October 2014

A dual-probe system can specifically capture DNA-binding proteins with an unmodified binding site.
Proxy-based accelerated discovery of Fischer–Tropsch catalysts
Authors: Boldrin Paul , Gallagher James R. , Combes Gary B. , Enache Dan I. , James David , Ellis Peter R. , Kelly Gordon , Claridge John B. , Rosseinsky Matthew J.
Published: October 2014

High-throughput XRD and TGA are used to screen hundreds of candidate Fischer–Tropsch synthesis catalyst samples per month for particle size, reducibility and stability under operating conditions. A series of highly stable catalysts based on Co-Ru-Mg-Al2O3 are identified.
Optical and electronic properties of air-stable organoboron compounds with strongly electron-accepting bis(fluoromesityl)boryl groups
Authors: Zhang Zuolun , Edkins Robert M. , Nitsch Jörn , Fucke Katharina , Steffen Andreas , Longobardi Lauren E. , Stephan Douglas W. , Lambert Christoph , Marder Todd B.
Published: October 2014

R–Ph–B(FMes)2compounds exhibit low reduction potentials, bright emission, a TICT state and unusual long-lived phosphorescence at low temperature.
Rechargeable Li//Br battery: a promising platform for post lithium ion batteries
Authors: Chang Zheng , Wang Xujiong , Yang Yaqiong , Gao Jie , Li Minxia , Liu Lili , Wu Yuping
Published: October 2014

Li//Br battery, by using aqueous bromide/tribromide redox pair as positive electrode and a coated lithium metal as negative electrode, exhibits high energy density and good cycling.
Quaternized chitosans bind onto preexisting biofilms and eradicate pre-attached microorganisms
Authors: Jiang Fuguang , Deng Ying , Yeh Chih-Ko , Sun Yuyu
Published: October 2014

Quaternized chitosans bind onto preexisting biofilms and eradicate pre-attached microorganisms.
Aminoacetone oxidase from Streptococcus oligofermentans belongs to a new three-domain family of bacterial flavoproteins
Authors: Molla Gianluca , Nardini Marco , Motta Paolo , D’Arrigo Paola , Panzeri Walter , Pollegioni Loredano
Published: October 2014

The aaoSo gene from Streptococcus oligofermentans encodes a 43 kDa flavoprotein, aminoacetone oxidase (SoAAO), which was reported to possess a low catalytic activity against several different L-amino acids; accordingly, it was classified as an L-amino acid oxidase. Subsequently, SoAAO was demonstrated to oxidize aminoacetone (a pro-oxidant metabolite), with an activity ~25-fold higher than the activity displayed on L-lysine, thus lending support to the assumption of aminoacetone as the preferred substrate. In the present study, we have characterized the SoAAO structure–function relationship. SoAAO is an FAD-containing enzyme that does not possess the classical properties of the oxidase/dehydrogenase class of flavoproteins (i.e. no flavin semiquinone formation is observed during anaerobic photoreduction as well as no reaction with sulfite) and does not show a true L-amino acid oxidase activity. From a structural point of view, SoAAO belongs to a novel protein family composed of three domains: an α/β domain corresponding to the FAD-binding domain, a β-domain partially modulating accessibility to the coenzyme, and an additional α-domain. Analysis of the reaction products of SoAAO on aminoacetone showed 2,5-dimethylpyrazine as the main product; we propose that condensation of two aminoacetone molecules yields 3,6-dimethyl-2,5-dihydropyrazine that is subsequently oxidized to 2,5-dimethylpyrazine. The ability of SoAAO to bind two molecules of the substrate analogue O-methylglycine ligand is thought to facilitate the condensation reaction. A specialized role for SoAAO in the microbial defence mechanism related to aminoacetone catabolism through a pathway yielding dimethylpyrazine derivatives instead of methylglyoxal can be proposed.
DNA polymerase η is regulated by poly(rC)-binding protein 1 via mRNA stability
Authors: Ren Cong , Cho Seong-Jun , Jung Yong-Sam , Chen Xinbin
Published: October 2014

POLH (DNA polymerase η), a target of p53 tumour suppressor, plays a key role in TLS (translesion DNA synthesis). Loss of POLH is responsible for the human cancer-prone syndrome XPV (xeroderma pigmentosum variant). Owing to its critical role in DNA repair and genome stability, POLH expression and activity are regulated by multiple pathways. In the present study, we found that the levels of both POLH transcript and protein were decreased upon knockdown of the transcript encoding PCBP1 [poly(rC)-binding protein 1]. We also found that the half-life of POLH mRNA was markedly decreased upon knockdown of PCBP1. Moreover, we found that PCBP1 directly bound to the POLH 3′-UTR and the PCBP1-binding site in POLH mRNA is an atypical AU-rich element. Finally, we showed that the AU-rich element in POLH 3′-UTR was responsive to PCBP1 and sufficient for PCBP1 to regulate POLH expression. Taken together, we uncovered a novel mechanism by which POLH expression is controlled by PCBP1 via mRNA stability.
Balanced BPF design of substrate‐integrated waveguide cavity using hybrid microstrip/slot feed for CM suppression
Authors: Chen Meng‐Yu , Hong Wanchu , Ho Min‐Hua
Published: October 2014

A dual‐mode balanced bandpass filter (BPF) design with an excellent common‐mode (CM) rejection performance is presented. The balanced filter is composed of coupled substrate‐integrated waveguide (SIW) cavities and a hybrid microstrip/slot feed. The cavities are of a square shape to produce two degenerated resonance modes, TE102 and TE201, for dual‐mode operation. The hybrid microstrip/slot feed is developed to suppress the unwanted CM signals in both the in‐band and out‐band regions. The measured CM signal rejection levels are over 50 dB. A experiment was conducted to verify this novel balanced BPF design.
Joint resource allocation and power control for cellular and device‐to‐device multicast based on cognitive radio
Authors: Wu Xiaolu , Chen Yueyun , Yuan Xiaopan , Mkiramweni Mbazingwa E.
Published: October 2014

Device‐to‐device (D2D) communication is an excellent technology for improving the system capacity through sharing the spectrum resources of cellular networks. Multicast service is considered an effective transmission mode for the future mobile social contact services. Therefore, multicast with D2D technology can improve the resource efficiency. In this paper, a resource allocation scheme based on cognitive radio (CR) for D2D underlay multicast communication (CR‐DUM) is proposed to improve system performance. In each D2D multicast group of the cognitive cellular system, the secondary users reuse the different orthogonal cellular resources to accomplish a multicast transmission. To maximise the total system capacity under the condition of interference and noise impairment, the authors formulate an optimal transmitting power allocation for the cellular and D2D multicast communications jointly. The proposed scheme includes two steps. First, two channel allocation rules are proposed to reduce the interference from cellular networks to receivers in D2D multicast group. Second, the optimal power allocation is formulated as a non‐linear programming problem and the optimal solution is achieved by searching from a finite set for the allocated channel. The simulation results show that the proposed method can ensure the quality of service (QoS) and improve the system capacity.
Optimal spectrum assignment for cognitive radio sensor networks under coverage constraint
Authors: Eletreby Rashad M. , Elsayed Hany M. , Khairy Mohamed M.
Published: October 2014

Cognitive radios emerged as a solution to spectrum scarcity problem. The integration of cognitive radios and wireless sensor networks enables a new paradigm of communication, in which the sensor nodes can avoid heavily‐crowded transmission bands by tuning their transmission parameters to less‐crowded bands. The authors consider the problem of spectrum assignment for cognitive radio sensor network (CRSN) under coverage, interference, minimum data rate and power budget constraints. A mixed‐integer non‐linear programming problem formulation that addresses optimal power allocation, channel selection and node scheduling is presented. Following a practical assumption, that any CRSN node can only access one channel for its transmission with the CRSN base station, the problem is transformed to a binary linear programming (BLP) problem. Using the relaxation techniques, the problem is transformed to a linear programming problem that is solvable in polynomial time, and has the same optimal solution of the BLP problem. Hence, the minimum power algorithm that achieves the optimal solution of our problem is proposed. To further reduce the complexity of the solution, three heuristic lower‐complexity algorithms are proposed to solve the problem: random, greedy and two‐stage (decoupled) algorithms.
Absolute calibration of the Agfa Structurix series films at energies between 2.7 and 6.2 keV
Authors: Lanier N. E. , Cowan J. S.
Published: October 2014

Although photo-emulsion technology is many decades old, x-ray film still remains a key asset for diagnosing hydrodynamic features in High-Energy Density (HED) experiments. For decades, the preferred option had been Kodak's direct exposure film. After its discontinuance in 2004, the push to find alternatives began. In many situations, the Agfa Structurix series offers the most favorable substitute, but being new to the HED community, its characterization was lacking. To remedy this, recent experiments, conducted at Brookhaven's National Synchrotron Light Source, provide absolute, monochromatic calibration data for the Agfa Structurix series films at K-shell backlighter energies between 2.7 and 6.2 keV. Absolute response curves are presented for Agfa D8, D7, D4, D4sc, D3, and D2. Moreover, the transmission of each film type is also measured.
On the separability of the extended molecule: Constructing the best localized molecular orbitals for an organic molecule bridging two model electrodes
Authors: Moreira Rodrigo A. , de Melo Celso P.
Published: October 2014

Based on a quantum chemical valence formalism that allows the rigorous construction of best-localized molecular orbitals on specific parts of an extended system, we examined the separability of individual components of model systems relevant to the description of electron transport in molecular devices. We started by examining how to construct the maximally localized electronic density at the tip of a realistic model of a gold electrode. By varying the number of gold atoms included in the local region where to project the total electronic density, we quantitatively assess how many molecular orbitals are entirely localized in that region. We then considered a 1,4-benzene-di-thiol molecule connected to two model gold electrodes and examined how to localize the electronic density of the total system in the extended molecule, a fractional entity comprising the organic molecule plus an increasing number of the closest metal atoms. We were able to identify in a rigorous manner the existence of three physically different electronic populations, each one corresponding to a distinct set of molecular orbitals. First, there are those entirely localized in the extended molecule, then there is a second group of those completely distributed in the gold atoms external to that region, and, finally, there are those delocalized over the entire system. This latter group can be associated to the shared electronic population between the extended molecule and the rest of the system. We suggest that the treatment here presented could be useful in the theoretical analysis of the electronic transport in nanodevices whenever the use of localized molecular states are required by the physics of the specific problem, such as in cases of weak coupling and super-exchange limits.
Wetting transparency of graphene in water
Authors: Driskill Joshua , Vanzo Davide , Bratko Dusan , Luzar Alenka
Published: October 2014

Measurements of contact angle on graphene sheets show a notable dependence on the nature of the underlying substrate, a phenomenon termed wetting transparency. Our molecular modeling studies reveal analogous transparency in case of submerged graphene fragments in water. A combined effect of attractive dispersion forces, angle correlations between aqueous dipoles, and repulsion due to the hydrogen-bond-induced orientation bias in polarized hydration layers acting across graphene sheet, enhances apparent adhesion of water to graphene. We show wetting free energy of a fully wetted graphene platelet to be about 8 mNm−1 lower than for graphene wetted only on one side, which gives close to 10° reduction in contact angle. This difference has potential implications for predictions of water absorption vs. desorption, phase behavior of water in aqueous nanoconfinements, solvent-induced interactions among graphitic nanoparticle and concomitant stability in aqueous dispersions, and can influence permeability of porous materials such as carbon nanotubes by water and aqueous solutions.
Compact and high-particle-flux thermal-lithium-beam probe system for measurement of two-dimensional electron density profile
Authors: Shibata Y. , Manabe T. , Kajita S. , Ohno N. , Takagi M. , Tsuchiya H. , Morisaki T.
Published: October 2014

A compact and high-particle-flux thermal-lithium-beam source for two-dimensional measurement of electron density profiles has been developed. The thermal-lithium-beam oven is heated by a carbon heater. In this system, the maximum particle flux of the thermal lithium beam was ∼4 × 1019 m−2 s−1 when the temperature of the thermal-lithium-beam oven was 900 K. The electron density profile was evaluated in the small tokamak device HYBTOK-II. The electron density profile was reconstructed using the thermal-lithium-beam probe data and this profile was consistent with the electron density profile measured with a Langmuir electrostatic probe. We confirm that the developed thermal-lithium-beam probe can be used to measure the two-dimensional electron density profile with high time and spatial resolutions.
Molecular interactions with ice: Molecular embedding, adsorption, detection, and release
Authors: Gibson K. D. , Langlois Grant G. , Li Wenxin , Killelea Daniel R. , Sibener S. J.
Published: October 2014

The interaction of atomic and molecular species with water and ice is of fundamental importance for chemistry. In a previous series of publications, we demonstrated that translational energy activates the embedding of Xe and Kr atoms in the near surface region of ice surfaces. In this paper, we show that inert molecular species may be absorbed in a similar fashion. We also revisit Xe embedding, and further probe the nature of the absorption into the selvedge. CF4 molecules with high translational energies (≥3 eV) were observed to embed in amorphous solid water. Just as with Xe, the initial adsorption rate is strongly activated by translational energy, but the CF4 embedding probability is much less than for Xe. In addition, a larger molecule, SF6, did not embed at the same translational energies that both CF4 and Xe embedded. The embedding rate for a given energy thus goes in the order Xe > CF4 > SF6. We do not have as much data for Kr, but it appears to have a rate that is between that of Xe and CF4. Tentatively, this order suggests that for Xe and CF4, which have similar van der Waals radii, the momentum is the key factor in determining whether the incident atom or molecule can penetrate deeply enough below the surface to embed. The more massive SF6 molecule also has a larger van der Waals radius, which appears to prevent it from stably embedding in the selvedge. We also determined that the maximum depth of embedding is less than the equivalent of four layers of hexagonal ice, while some of the atoms just below the ice surface can escape before ice desorption begins. These results show that energetic ballistic embedding in ice is a general phenomenon, and represents a significant new channel by which incident species can be trapped under conditions where they would otherwise not be bound stably as surface adsorbates. These findings have implications for many fields including environmental science, trace gas collection and release, and the chemical composition of astrophysical icy bodies in space.
Variable density turbulence tunnel facility
Authors: Bodenschatz E. , Bewley G. P. , Nobach H. , Sinhuber M. , Xu H.
Published: October 2014

The Variable Density Turbulence Tunnel at the Max Planck Institute for Dynamics and Self-Organization in Göttingen, Germany, produces very high turbulence levels at moderate flow velocities, low power consumption, and adjustable kinematic viscosity between 10−4 m2/s and 10−7 m2/s. The Reynolds number can be varied by changing the pressure or flow rate of the gas or by using different non-flammable gases including air. The highest kinematic viscosities, and hence lowest Reynolds numbers, are reached with air or nitrogen at 0.1 bar. To reach the highest Reynolds numbers the tunnel is pressurized to 15 bars with the dense gas sulfur hexafluoride (SF6). Turbulence is generated at the upstream ends of two measurement sections with grids, and the evolution of this turbulence is observed as it moves down the length of the sections. We describe the instrumentation presently in operation, which consists of the tunnel itself, classical grid turbulence generators, and state-of-the-art nano-fabricated hot-wire anemometers provided by Princeton University [M. Vallikivi, M. Hultmark, S. C. C. Bailey, and A. J. Smits, Exp. Fluids 51, 1521 (2011)]. We report measurements of the characteristic scales of the flow and of turbulent spectra up to Taylor Reynolds number Rλ ≈ 1600, higher than any other grid-turbulence experiment. We also describe instrumentation under development, which includes an active grid and a Lagrangian particle tracking system that moves down the length of the tunnel with the mean flow. In this configuration, the properties of the turbulence are adjustable and its structure is resolvable up to Rλ ≈ 8000.
Neutron measurements from beam-target reactions at the ELISE neutral beam test facility
Authors: Xufei X. , Nocente M. , Bonomo F. , Franzen P. , Fröschle M. , Grosso G. , Grünauer F. , Pasqualotto R. , Tardocchi M. , Fan T. , Gorini G.
Published: October 2014

Measurements of 2.5 MeV neutron emission from beam-target reactions performed at the ELISE neutral beam test facility are presented in this paper. The measurements are used to study the penetration of a deuterium beam in a copper dump, based on the observation of the time evolution of the neutron counting rate from beam-target reactions with a liquid scintillation detector. A calculation based on a local mixing model of deuterium deposition in the target up to a concentration of 20% at saturation is used to evaluate the expected neutron yield for comparison with data. The results are of relevance to understand neutron emission associated to beam penetration in a solid target, with applications to diagnostic systems for the SPIDER and MITICA Neutral Beam Injection prototypes.
Integrated-fin gasket for palm cubic-anvil high pressure apparatus
Authors: Cheng J.-G. , Matsubayashi K. , Nagasaki S. , Hisada A. , Hirayama T. , Hedo M. , Kagi H. , Uwatoko Y.
Published: October 2014

We described an integrated-fin gasket technique for the palm cubic-anvil apparatus specialized for the high-pressure and low-temperature measurements. By using such a gasket made from the semi-sintered MgO ceramics and the tungsten-carbide anvils of 2.5 mm square top, we successfully generate pressures over 16 GPa at both room and cryogenic temperatures down to 0.5 K. We observed a pressure self-increment for this specific configuration and further characterized the thermally induced pressure variation by monitoring the antiferromagnetic transition temperature of chromium up to 12 GPa. In addition to enlarge the pressure capacity, such a modified gasket also improves greatly the surviving rate of electrical leads hanging the sample inside a Teflon capsule filled with the liquid pressure-transmitting medium. These improvements should be attributed to the reduced extrusion of gasket materials during the initial compression.
Theoretical study of time-resolved luminescence in semiconductors. I. Decay from the steady state
Authors: Maiberg Matthias , Scheer Roland
Published: October 2014

Time-resolved luminescence (TRL) is a non-destructive, non-invasive, and contactless characterization method. We studied TRL decay on semiconductor layers and thin film homostructures after a steady state illumination by simulation with Synopsys TCAD® and by analytical approximate solution of the appropriate equations. First, we show that the luminescence decay time in general equals the minority carrier lifetime only for a homogeneous and time-independent carrier lifetime. Then, we investigate the influence of photon recycling, injection level, charge carrier diffusion, defects in the bulk and at the surfaces, as well as space charge on the TRL decay separately by quasi one-dimensional simulations of semiconductor layers and semiconductor homostructures. We further study the influence of sample non-homogeneity as may be found in polycrystalline semiconductors. We show how carrier lifetime can be extracted from the TRL transients and how the samples can be characterized by excitation dependent measurements in the open circuit case. We can explain some effects found in luminescence experiments, like a decrease of the decay time with an increasing excitation, a maximum in the decay time due to saturated bulk-defects and curved luminescence transients due to high injections or sample inhomogeneities. Furthermore, we are focussing on the question, how single layers within a semiconductor stack can be characterized.
Ultra-thin optical interference coatings on rough and flexible substrates
Authors: Kats Mikhail A. , Capasso Federico
Published: October 2014

Recently demonstrated ultra-thin optical coatings comprising nanometer-thick highly absorbing films on top of reflecting substrates can display strong optical interference effects, resulting in structural colors and absorption enhancement. Here, we demonstrate that these optical interference effects persist when the films are deposited on substrates that have a large degree of roughness and inhomogeneity on micro- and nano-scales. In particular, we deposited films of gold and amorphous germanium onto paper which serves as a rough and flexible substrate and observe matte interference colors that vary as a function of the germanium thickness.
Doping-tunable thermal emission from plasmon polaritons in semiconductor epsilon-near-zero thin films
Authors: Jun Young Chul , Luk Ting S. , Robert Ellis A. , Klem John F. , Brener Igal
Published: October 2014

We utilize the unique dispersion properties of leaky plasmon polaritons in epsilon-near-zero (ENZ) thin films to demonstrate thermal radiation control. Owing to its highly flat dispersion above the light line, a thermally excited leaky wave at the ENZ frequency out-couples into free space without any scattering structures, resulting in a narrowband, wide-angle, p-polarized thermal emission spectrum. We demonstrate this idea by measuring angle- and polarization-resolved thermal emission spectra from a single layer of unpatterned, doped semiconductors with deep-subwavelength film thickness (d/λ0 ∼ 6×10−3, where d is the film thickness and  λ0 is the free space wavelength). We show that this semiconductor ENZ film effectively works as a leaky wave thermal radiation antenna, which generates far-field radiation from a thermally excited mode. The use of semiconductors makes the radiation frequency highly tunable by controlling doping densities and also facilitates device integration with other components. Therefore, this leaky plasmon polariton emission from semiconductor ENZ films provides an avenue for on-chip control of thermal radiation.
Beneficial compressive strain for oxygen reduction reaction on Pt (111) surface
Authors: Kattel Shyam , Wang Guofeng
Published: October 2014

We investigated the influence of compressive surface strain on the progression of oxygen reduction reaction (ORR) on Pt(111) surface using the density functional theory (DFT) calculation method. Specifically, we calculated the binding energies of all the chemical species possibly involved in ORR and the reaction energies (heat of reaction and activation energy) of all the possible ORR elementary reactions on the Pt(111) surfaces with −2% and −3% strain. Our DFT results indicate that all the ORR species bind more weakly on the compressively strained surfaces than on an unstrained surface owing to strain-induced d-electron band broadening. Our DFT calculations further predict that both OOH dissociation and HOOH dissociation pathways could be active for ORR on the Pt(111) surface with compressive strain between −2% and −3%. Moreover, the activation energies of the ORR rate-determining steps on the compressively strained Pt(111) surfaces were found to be lower than that on the unstrained Pt(111) surface. It was thus inferred that a −2% to −3% surface strain could lead to enhanced ORR activity on the Pt(111) catalysts. Consequently, our study suggests that tuning surface strain is an effective way to improve the performance of Pt-based electrocatalysts for ORR.
Dynamics of the reaction of C3(a3Πu) radicals with C2H2: A new source for the formation of C5H
Authors: Huang Wen-Jian , Sun Yi-Lun , Chin Chih-Hao , Lee Shih-Huang
Published: October 2014

The reaction C3(a3Πu) + C2H2 → C5H + H was investigated at collision energy 10.9 kcal mol−1 that is less than the enthalpy of ground-state reaction C3(X1Σg+) + C2H2 → C5H + H. C3(a3Πu) radicals were synthesized from 1% C4F6/He by pulsed high-voltage discharge. The title reaction was conducted in a crossed molecular-beam apparatus equipped with a quadrupole-mass filter. Product C5H was interrogated with time-of-flight spectroscopy and synchrotron vacuum-ultraviolet ionization. Reactant C3(a3Πu) and product C5H were identified using photoionization spectroscopy. The ionization thresholds of C3(X1Σg+) and C3(a3Πu) are determined as 11.6 ± 0.2 eV and 10.0 ± 0.2 eV, respectively. The C5H product is identified as linear pentynylidyne that has an ionization energy 8.4 ± 0.2 eV. The title reaction releases translational energy 10.6 kcal mol−1 in average and has an isotropic product angular distribution. The quantum-chemical calculation indicates that the C3(a3Πu) radical attacks one of the carbon atoms of C2H2 and subsequently a hydrogen atom is ejected to form C5H + H, in good agreement with the experimental observation. As far as we are aware, the C3(a3Πu) + C2H2 reaction is investigated for the first time. This work gives an implication for the formation of C5H from the C3(a3Πu) + C2H2 reaction occurring in a combustion or discharge process of C2H2.
Effect of partial exfoliation in carbon dioxide adsorption-desorption properties of carbon nanotubes
Authors: Tamilarasan P. , Ramaprabhu S.
Published: October 2014

In this study, we have experimentally studied the effect of partial exfoliation in low-pressure (<100 kPa) carbon dioxide adsorption and desorption behavior of multiwalled carbon nanotubes (MWNTs). MWNTs were partially exfoliated by controlled oxidation followed by hydrogen assisted low temperature exfoliation method. The adsorption capacity of partially exfoliated MWNTs (PEMWNTs) is 3.4 times that of MWNTs. Adsorption-desorption isotherms of MWNTs are unique, which shows trapping behavior. The desorption behavior in association with isothermal adsorbate retention of MWNTs and PEMWNTs suggests possible CO2 trapping inside the tubes and at interstitials. It is found that the CO2 adsorbed PEMWNTs system has higher molecular orbital energy than CO2 adsorbed MWNTs system. Areal adsorption capacity analysis suggests the significant influence of surface functional groups on adsorption capacity. Adsorption isosteres of both adsorbents follow the Arrhenius relation stating the temperature dependent adsorption rate. The isosteric heats and change in entropy of adsorption have been determined at multiple adsorbed amounts from the corresponding adsorption isosteres.
High performance AlScN thin film based surface acoustic wave devices with large electromechanical coupling coefficient
Authors: Wang Wenbo , Mayrhofer Patrick M. , He Xingli , Gillinger Manuel , Ye Zhi , Wang Xiaozhi , Bittner Achim , Schmid Ulrich , Luo J. K.
Published: October 2014

AlN and AlScN thin films with 27% scandium (Sc) were synthesized by DC magnetron sputtering deposition and used to fabricate surface acoustic wave (SAW) devices. Compared with AlN-based devices, the AlScN SAW devices exhibit much better transmission properties. Scandium doping results in electromechanical coupling coefficient, K2, in the range of 2.0% ∼ 2.2% for a wide normalized thickness range, more than a 300% increase compared to that of AlN-based SAW devices, thus demonstrating the potential applications of AlScN in high frequency resonators, sensors, and high efficiency energy harvesting devices. The coupling coefficients of the present AlScN based SAW devices are much higher than that of the theoretical calculation based on some assumptions for AlScN piezoelectric material properties, implying there is a need for in-depth investigations on the material properties of AlScN.
Ferroic characterizations, phase transformation, and internal bias field in 0.75Pb(Fe2/3W1/3)O3–0.25PbTiO3 multiferroic ceramic
Authors: Zheng Mupeng , Hou Yudong , Ai Zhirong , Zhu Mankang
Published: October 2014

The complex perovskite of 0.75Pb(Fe2/3W1/3)O3–0.25PbTiO3 (0.75PFW-0.25PT) ceramic was prepared by the conventional oxide mixing method. The detailed microstructure of 0.75PFW-0.25PT ceramic was investigated. At room temperature, the TEM analysis reveals that only cubic structure (nonpolar) exists, which is different from the phase coexistence of cubic (66%) and tetragonal (34%) structure revealed by XRD. A mechanism dominated by a temperature rise due to electron-beam irradiation has been proposed. The XPS measurement confirms the mixed balance state of Fe2+ and Fe3+ in the as-prepared 0.75PFW-0.25PT specimen, which facilitates the formation of the defect dipoles with oxygen vacancies, in turn resulting in the internal-bias field (Ei) phenomenon. The appearance of weak magnetic interactions is believed relating to the presence of noncompensated magnetic moments in Fe-rich islands. These results provide key information for understanding the composition, defect, ferroelectric, and ferromagnetic properties in 0.75PFW-0.25PT ceramic.
Charge transfer and mobility enhancement at CdO/SnTe heterointerfaces
Authors: Nishitani Junichi , Yu Kin Man , Walukiewicz Wladek
Published: October 2014

We report a study of the effects of charge transfer on electrical properties of CdO/SnTe heterostructures. A series of structures with variable SnTe thicknesses were deposited by RF magnetron sputtering. Because of an extreme type III band offset with the valence band edge of SnTe located at 1.5 eV above the conduction band edge of CdO, a large charge transfer is expected at the interface of the CdO/SnTe heterostructure. The electrical properties of the heterostructures are analyzed using a multilayer charge transport model. The analysis indicates a large 4-fold enhancement of the CdO electron mobility at the interface with SnTe. The mobility enhancement is attributed to reduction of the charge center scattering through neutralization of the donor-like defects responsible for the Fermi level pinning at the CdO/SnTe interface.
AlGaN/GaN field effect transistors functionalized with recognition peptides
Authors: Rohrbaugh N. , Bryan I. , Bryan Z. , Arellano C. , Collazo R. , Ivanisevic A.
Published: October 2014

Recognition peptides are used to modify AlGaN/GaN field effect transistors. The recognition sequence, SVSVGMKPSPRP, was compared to other biomolecules and subsequently the device stability was examined. Changes in the electrical characteristic were recorded using current-voltage measurements at a VD of 1 V and VG of −1 V. The recognition sequence coatings yielded an average increase in ID of 96.43% compared to initial values. Exposure to solution removed the peptides from the devices indicating a weak interaction between adsorbate and the semiconductor surfaces. The peptide coatings are suitable for simple device modification for short-term recognition studies.
Trap-assisted tunneling in InGaN/GaN single-quantum-well light-emitting diodes
Authors: Auf der Maur M. , Galler B. , Pietzonka I. , Strassburg M. , Lugauer H. , Di Carlo A.
Published: October 2014

Based on numerical simulation and comparison with measured current characteristics, we show that the current in InGaN/GaN single-quantum-well light-emitting diodes at low forward bias can be accurately described by a standard trap-assisted tunneling model. The qualitative and quantitative differences in the current characteristics of devices with different emission wavelengths are demonstrated to be correlated in a physically consistent way with the tunneling model parameters.
Partial homogeneity based high-resolution nuclear magnetic resonance spectra under inhomogeneous magnetic fields
Authors: Wei Zhiliang , Lin Liangjie , Chen Youhe , Lin Yanqin , Chen Zhong
Published: October 2014

In nuclear magnetic resonance (NMR) technique, it is of great necessity and importance to obtain high-resolution spectra, especially under inhomogeneous magnetic fields. In this study, a method based on partial homogeneity is proposed for retrieving high-resolution one-dimensional NMR spectra under inhomogeneous fields. Signals from series of small voxels, which characterize high resolution due to small sizes, are recorded simultaneously. Then, an inhomogeneity correction algorithm is developed based on pattern recognition to correct the influence brought by field inhomogeneity automatically, thus yielding high-resolution information. Experiments on chemical solutions and fish spawn were carried out to demonstrate the performance of the proposed method. The proposed method serves as a single radiofrequency pulse high-resolution NMR spectroscopy under inhomogeneous fields and may provide an alternative of obtaining high-resolution spectra of in vivo living systems or chemical-reaction systems, where performances of conventional techniques are usually degenerated by field inhomogeneity.
Significant roles of low-temperature post-metallization annealing in solution-processed oxide thin-film transistors
Authors: Xu Yong , Liu Chuan , Amegadze Paul Seyram K. , Park Won-Tae , Long Dang Xuan , Minari Takeo , Balestra Francis , Ghibaudo Gerard , Noh Yong-Young
Published: October 2014

Inspired by the silicide technology in manufacturing silicon devices and the ongoing lack of knowledge on post-metallization annealing in realizing oxide devices, we investigated post-contact annealing for solution-processed InGaZnO transistors. Low-temperature annealing in air is found to significantly improve device uniformity, reproducibility, and subthreshold charge transport. However, this method is highly dependent on the employed contact metal. Detailed examination of devices using Al, Au, and Cu reveals that the physics of a metal/semiconductor interface is vital to its post-anneal response, which results in distinct device characteristics. Our results provide clues to better understand oxide transistors and to optimize their performance.
Radiation stability of graphene under extreme conditions
Authors: Kumar Sunil , Tripathi Ambuj , Khan Saif A. , Pannu Compesh , Avasthi Devesh K.
Published: October 2014

In this letter, we report radiation stability of graphene under extreme condition of high energy density generated by 150 MeV Au ion irradiation. The experiment reveals that graphene is radiation resistant for irradiation at 1014 ions/cm2 of 150 MeV Au ions. It is significant to note that annealing effects are observed at lower fluences whereas defect production occurs at higher fluences but significant crystallinity is retained. Our results demonstrate applicability of graphene based devices in radiation environment and space applications.
Manipulation of transport hysteresis on graphene field effect transistors with Ga ion irradiation
Authors: Wang Quan , Liu Shuai , Ren Naifei
Published: October 2014

We have studied the effect of Ga ion irradiation on the controllable hysteretic behavior of graphene field effect transistors fabricated on Si/SO2 substrates. The various densities of defects in graphene were monitored by Raman spectrum. It was found that the Dirac point shifted to the positive gate voltage constantly, while the hysteretic behavior was enhanced first and then weakened, with the dose of ion irradiation increasing. By contrasting the trap charges density induced by dopant and the total density of effective trap charges, it demonstrated that adsorbate doping was not the decisive factor that induced the hysteretic behavior. The tunneling between the defect sites induced by ion irradiation was also an important cause for the hysteresis.
High thermoelectric figure of merit in nanocrystalline polyaniline at low temperatures
Authors: Nath Chandrani , Kumar Ashok , Kuo Yung-Kang , Okram Gunadhor Singh
Published: October 2014

Thermoelectric coolers with figure of merit (ZT) close to unity at low temperatures are the need of the hour with new advances in high temperature superconductors, superconducting microelectronic circuits, quantum computers, and photonics. Here, we demonstrate that the conducting polymer polyaniline (Pani) doped with camphor sulfonic acid synthesized in semi-crystalline nanostructures, possesses a giant Seebeck effect at low temperatures. The resulting enormously large Seebeck coefficient (up to 0.6 V/K) combined with an intrinsically low electrical conductivity and thermal conductivity give rise to a ZT = 0.77 at 45 K and ZT = 2.17 at 17 K.
Back reflectors based on buried Al2O3 for enhancement of photon recycling in monolithic, on-substrate III-V solar cells
Authors: García I. , Kearns-McCoy C. F. , Ward J. S. , Steiner M. A. , Geisz J. F. , Kurtz S. R.
Published: October 2014

Photon management has been shown to be a fruitful way to boost the open circuit voltage and efficiency of high quality solar cells. Metal or low-index dielectric-based back reflectors can be used to confine the reemitted photons and enhance photon recycling. Gaining access to the back of the solar cell for placing these reflectors implies having to remove the substrate, with the associated added complexity to the solar cell manufacturing. In this work, we analyze the effectiveness of a single-layer reflector placed at the back of on-substrate solar cells, and assess the photon recycling improvement as a function of the refractive index of this layer. Al2O3-based reflectors, created by lateral oxidation of an AlAs layer, are identified as a feasible choice for on-substrate solar cells, which can produce a Voc increase of around 65% of the maximum increase attainable with an ideal reflector. The experimental results obtained using prototype GaAs cell structures show a greater than two-fold increase in the external radiative efficiency and a Voc increase of ∼2% (∼18 mV), consistent with theoretical calculations. For GaAs cells with higher internal luminescence, this Voc boost is calculated to be up to 4% relative (36 mV), which directly translates into at least 4% higher relative efficiency.
Captured cosmic dust may have interstellar origins
Authors: Smart Ashley G.
Published: October 2014

The multiyear effort that identified the candidate interstellar grains was, in part, a triumph of citizen science.