bluuebunny/crossref_metadata_2025 huggingface dataset:
A simple pincer-type chemosensor for reversible fluorescence turn-on detection of zinc ion at physiological pH range
Authors: Lin Qi , Cai Yi , Li Qiao , Chang Jing , Yao Hong , Zhang You-Ming , Wei Tai-Bao
Published: March 2015

A dihydrazone based pincer-type chemosensor (Y) which could detect zinc at physiological pH range with reversible fluorescence “Off–On–Off”.
Palladium supported on hollow magnetic mesoporous spheres: a recoverable catalyst for hydrogenation and Suzuki reaction
Authors: Liu Hengzhi , Wang Peng , Yang Honglei , Niu Jianrui , Ma Jiantai
Published: March 2015

Highly efficient and magnetically recoverable HMMS–saplr–Pd(0) was developed for hydrogenation and Suzuki reaction.
Elucidation of several neglected reactions in the GC–MS identification of sialic acids as heptafluorobutyrates calls for an urgent reassessment of previous claims
Authors: Rota Paola , Anastasia Luigi , Allevi Pietro
Published: March 2015

A revision of the analytical protocol for the GC–MS determination of free or 1,7-lactonized sialic acids as heptafluorobutyrates is reported.
Manganese(iii)-mediated alkenyl Csp2–P bond formation from the reaction of β-nitrostyrenes with dialkyl phosphites
Authors: Xue Jian-Fei , Zhou Shao-Fang , Liu Ye-Ye , Pan Xiangqiang , Zou Jian-Ping , Asekun Olayinka Taiwo
Published: March 2015

Mn(OAc)3-mediated tandem phosphonyl radical addition to β-nitrostyrenes followed by denitration to form (E)-2-alkenyl phosphonates is described.
PhI(OAc)2 mediated decarboxylative sulfonylation of β-aryl-α,β-unsaturated carboxylic acids: a synthesis of (E)-vinyl sulfones
Authors: Katrun Praewpan , Hlekhlai Sornsiri , Meesin Jatuporn , Pohmakotr Manat , Reutrakul Vichai , Jaipetch Thaworn , Soorukram Darunee , Kuhakarn Chutima
Published: March 2015

A novel and expedient method for the decarboxylative sulfonylation of β-aryl-α,β-unsaturated carboxylic acids to their (E)-vinyl sulfones is described.
Polyelectrolyte/mesoporous silica hybrid materials for the high performance multiple-detection of pH value and temperature
Authors: Chen Feng , Jiang Xiaoping , Kuang Tairong , Chang Lingqian , Fu Dajiong , Yang Jintao , Fan Ping , Zhong Mingqiang
Published: March 2015

Mesoporous silica nanoparticles are modified by electrolyte polymer, giving significant ionic permselectivity under pH and/or temperature switches.
Palladium-catalyzed oxygenation of C(sp2)–H and C(sp3)–H bonds under the assistance of oxalyl amide
Authors: Liu Pei , Han Jian , Chen Chang Peng , Shi Da Qing , Zhao Ying Sheng
Published: March 2015

A general palladium catalyzed selective γ-oxygenation of oxalyl amide protected amines is accomplished under mild condition.
Bowl-like sulfur particles wrapped by graphene oxide as cathode material of lithium–sulfur batteries
Authors: Sun Chunxiao , Shi Lin , Fan Chenyao , Fu Xinxin , Ren Zhimin , Qian Guodong , Wang Zhiyu
Published: March 2015

We successfully synthesized sulfur particles with a bowl-like structure and wrapped them in graphene oxide (GO) via a simple method.
Theoretical design and characterization of pyridalthiadiazole-based chromophores with fast charge transfer at donor/acceptor interface toward small molecule organic photovoltaics
Authors: Li Shuang-Bao , Duan Yu-Ai , Geng Yun , Gao Hong-Ze , Qiu Yong-Qing , Su Zhong-Min
Published: March 2015

The designed 2, 3, and 5 will be promising donor candidates for high-performance OPV device due to their fast intermolecular charge transfer and effective charge transport.
The dielectric properties of low temperature thermally cross-linked polystyrene and poly(methyl methacrylate) thin films
Authors: Li Shengxia , Zhang Qing
Published: March 2015

Thermal cross-linking polystyrene and poly(methyl methacrylate) thin-films with 1,3,5-tris(2-propynyloxy)benzene at low temperature for dielectric applications.
One-pot synthesis of hierarchical WO3 hollow nanospheres and their gas sensing properties
Authors: Wang Chong , Feng Changhao , Wang Meng , Li Xin , Cheng Pengfei , Zhang Hong , Sun Yanfeng , Sun Peng , Lu Geyu
Published: March 2015

A simple solvothermal method was used for the synthesis of hollow nanosphered WO3, which exhibited a good response to NO2.
Directly printed stretchable strain sensor based on ring and diamond shaped silver nanowire electrodes
Authors: Lee Hyungdong , Seong Baekhoon , Moon Hyungpil , Byun Doyoung
Published: March 2015

Printing Ag NWs/PDMS composite strain gauge. The Ag NWs networks were formed just on top of the PDMS layer.
Use of a tin antimony alloy-filled porous carbon nanofiber composite as an anode in sodium-ion batteries
Authors: Chen Chen , Fu Kun , Lu Yao , Zhu Jiadeng , Xue Leigang , Hu Yi , Zhang Xiangwu
Published: March 2015

A tin antimony alloy-filled porous carbon nanofiber composite prepared by electrospinning exhibited high capacity and stable rate capability for use as an anode material in next-generation sodium-ion batteries.
Computational investigation of the ligand field effect to improve the photoacoustic properties of organometallic carbonyl clusters
Authors: Bag Arijit , Ghorai Pradip Kr.
Published: March 2015

Organometallic nitrosyl carbonyl clusters are stable and better high-contrast photoacoustic contrast agents (PACAs) than organometallic carbonyl clusters.
Anisotropic growth of Ni3(BO3)2 nanowhiskers on nickel substrates and its application in the fabrication of superhydrophilic surfaces
Authors: Wang Yifeng , Feng Jicai , Feng Bin , Song Xiaoguo , Cao Jian
Published: March 2015

One-dimensional single-crystalline Ni3(BO3)2 nanowhiskers were grown on Ni substrates using molten-salt method in air with MnO2 as the agent.
Preparation of novel silicon/nitrogen-doped graphene composite nanosheets by DC arc discharge
Authors: Shah Sayyar Ali , Cui Lan , Lin Kui , Xue Tao , Guo Qianjin , Li Ling , Zhang Lishuang , Zhang Fan , Hu Fengxiang , Wang Xitao , Wang Hui , Chen Xiaoping , Cui Shen
Published: March 2015

Silicon/nitrogen-doped graphene composite nanosheets were prepared by DC arc discharge and their suspensions emitted green luminescence under irradiation of UV light.
Ground and excited states of naphthalene–water (naphtha–W6) clusters: a computational study
Authors: Sharma Divya , Paterson Martin J.
Published: March 2015

An MP2 and DFT study of the structures of naphthalene–water hexamer clusters has been performed for both the prism and cage forms of the cluster.
Curcumin induces structural change and reduces the growth of amyloid-β fibrils: a QCM-D study
Authors: Wang Conggang , Xu Li , Cheng Fang , Wang Hanqi , Jia Lingyun
Published: March 2015

Curcumin inhibited Aβ fibril growth through leading to the structural conversion of the growing fibril to a more loosely constructed aggregate.
Cytotoxic saponin poliusaposide from Teucrium polium
Authors: Elmasri Wael A. , Hegazy Mohamed-Elamir F. , Mechref Yehia , Paré Paul W.
Published: March 2015

Three saponin glycosides have been isolated and characterized from Teucrium polium L. (Lamiaceae).
A novel approach to reduction of CO2into methanol by water splitting with aluminum over a copper catalyst
Authors: Lyu Lingyun , Jin Fangming , Zhong Heng , Chen Hongjuan , Yao Guodong
Published: March 2015

A novel method of water splitting for CO2reduction into methanol was proposed by directly using commercially available and non-precious Al and Cu powder as a reductant and catalyst, respectively.
Aryl tosylates as non-ionic photoacid generators (PAGs): photochemistry and applications in cationic photopolymerizations
Authors: Torti Edoardo , Della Giustina Gioia , Protti Stefano , Merli Daniele , Brusatin Giovanna , Fagnoni Maurizio
Published: March 2015

Irradiation of aryl tosylates leads to homolysis of the ArO–S bond and PTSA or p-toluenesulfinic acid was released. The aryl sulfonates tested were then used as non-ionic photoacid generators (PAGs) in hybrid organic/inorganic sol–gel photoresists.
Synthesis of CdTe/P(St-nBA-AA) pierced fluorescent microspheres
Authors: Wang Shenqiang , Zhang Hepeng , Chen Xin , Li Huan , Wang Hai , Li Peitao , Zhang Baoliang , Zhang Qiuyu
Published: March 2015

The formation mechanism involved the swelling, movement and winding of the adjacent polymer chains.
Effect of Al evaporation temperature on the properties of Al films grown on sapphire substrates by molecular beam epitaxy
Authors: Wang Wenliang , Yang Weijia , Liu Zuolian , Wang Haiyan , Lin Yunhao , Zhou Shizhong , Lin Zhiting , Qian Huirong , Wen Lei , Yang Meijuan , Zhu Yunnong , Liu Guorong , Gao Fangliang , Li Guoqiang
Published: March 2015

The effect of Al evaporation temperature on the properties of Al films grown on sapphire substrates by molecular beam epitaxy has been studied in detail.
Unusual phosphine oxidation: new triazolopyridyl-quinolyl phosphine oxide fluorescent dyes
Authors: Ballesteros-Garrido R. , Abarca B. , Ballesteros R. , Colobert F. , Leroux F. R. , García-España E.
Published: March 2015

3-(2-Pyridyl)-[1,2,3]triazolo[1,5-a]quinolylphosphines suffer an unusual phosphine oxidation due to their special geometry that allows a σ-donation of the nitrogen (N1) lone pair to phosphorus.
Palladium-catalyzed cross-coupling of α-bromocarbonyls and allylic alcohols for the synthesis of α-aryl dicarbonyl compounds
Authors: Yu Yang , Tambar Uttam K.
Published: March 2015

A palladium-catalyzed coupling of α-bromocarbonyl compounds and allylic alcohols has been developed for the generation of acyclic aryl-substituted dicarbonyl compounds.
A new lattice Monte Carlo simulation for dielectric saturation in ion-containing liquids
Authors: Duan Xiaozheng , Nakamura Issei
Published: March 2015

We develop a new, rapid method for the lattice Monte Carlo simulation of ion-containing liquids that accounts for the effects of the reorganization of solvent dipoles under external electrostatic fields.
Solar cells for self-sustainable intelligent packaging
Authors: Vicente António , Águas Hugo , Mateus Tiago , Araújo Andreia , Lyubchyk Andriy , Siitonen Simo , Fortunato Elvira , Martins Rodrigo
Published: March 2015

Nowadays there is a strong demand for intelligent packaging to provide comfort, welfare and security to owners, vendors and consumers by allowing them to know the contents and interact with the goods.
Luminescence properties and energy transfer of Ce3+/Tb3+ co-doped Ca6Ba(PO4)4O phosphor for near-UV pumped light-emitting diodes
Authors: Chen Mingyue , Xia Zhiguo , Liu Quanlin
Published: March 2015

The energy transfer process from Ce3+ to Tb3+ in Ca6Ba(PO4)4O and its mechanisms have been studied.
Poly(3-hexylthiophene)–graphene composite-based aligned nanofibers for high-performance field effect transistors
Authors: Lin Chih-Jung , Liu Cheng-Liang , Chen Wen-Chang
Published: March 2015

A high-performance FET with a maximum mobility of 1.82 cm2 V−1 s−1 was fabricated from aligned electrospun P3HT–graphene composite nanofibers.
Facile morphological control of fluorescent nano/microstructures via self-assembly and phase separation of trigonal azobenzenes showing aggregation-induced emission enhancement in polymer matrices
Authors: Han Mina , Takeoka Yukikazu , Seki Takahiro
Published: March 2015

We report a facile strategy for constructing diverse nano/microstructured morphologies via self-assembly and phase separation of trigonal azobenzene chromophores showing AIEE in polymer matrices.
Achieving Social Alignment between Business and IT – an Empirical Evaluation of the Efficacy of IT Governance Mechanisms
Authors: Schlosser Frank , Beimborn Daniel , Weitzel Tim , Wagner Heinz-Theo
Published: March 2015

How can firms improve the degree of social alignment between their business and IT units? Many years of research have shown the importance of business-IT alignment and its various facets, yet research on the efficacy of IT governance mechanisms to improve business-IT alignment is scarce. In this paper, we develop a model of social alignment at the operational level that considers the degree of social capital between an organization's business and IT units, IT personnel's business understanding, and a set of formal and informal IT governance mechanisms that drive the creation of social alignment and business value. Using survey data from 132 US banks, we show that social alignment is driven to varying degrees by a broad variety of IT governance mechanisms ranging from top management support and IT representation on the executive board to joint IT planning and IS training, regular meeting cycles, and liaison units. Our research contributes substantially to the practical demand on business-IT alignment research for an effective toolkit of IT governance mechanisms.
A High Performance Computing Cluster under Attack: The Titan Incident
Authors: McLaughlin Mark-David J , Cram W Alec , Gogan Janis L
Published: March 2015

At the University of Oslo (UiO), CERT manager Margrete Raaum learned of a network attack on Titan, a high-performance computing cluster that supported research conducted by scientists at CERT and other research institutions across Europe. The case describes the incident response, investigation, and clarification of the information security events that took place. As soon as Raaum learned of the attack, she ordered that the system be disconnected from the Internet to contain the damage. Next, she launched an investigation, which over a few days pieced together logs from previous weeks to identify suspicious activity and locate the attack vector. Raaum hopes to soon return Titan to its prior safe condition. In order to do so, she must decide what tasks still need to be completed to validate the systems and determine if it is safe to reconnect it to the Internet. She must also consider further steps to improve her team's ability to prevent, detect, and respond to similar incidents in the future. This case is designed for an undergraduate or graduate information security (infosec) class that includes students with varied technical and business backgrounds. The case supports discussion of technical and managerial infosec issues in inter-organizational systems – a topic that is currently underrepresented in major case collections.
Relativistic four-component calculations of indirect nuclear spin-spin couplings with efficient evaluation of the exchange-correlation response kernel
Authors: Křístková Anežka , Komorovsky Stanislav , Repisky Michal , Malkin Vladimir G. , Malkina Olga L.
Published: March 2015

In this work, we report on the development and implementation of a new scheme for efficient calculation of indirect nuclear spin-spin couplings in the framework of four-component matrix Dirac-Kohn-Sham approach termed matrix Dirac-Kohn-Sham restricted magnetic balance resolution of identity for J and K, which takes advantage of the previous restricted magnetic balance formalism and the density fitting approach for the rapid evaluation of density functional theory exchange-correlation response kernels. The new approach is aimed to speedup the bottleneck in the solution of the coupled perturbed equations: evaluation of the matrix elements of the kernel of the exchange-correlation potential. The performance of the new scheme has been tested on a representative set of indirect nuclear spin-spin couplings. The obtained results have been compared with the corresponding results of the reference method with traditional evaluation of the exchange-correlation kernel, i.e., without employing the fitted electron densities. Overall good agreement between both methods was observed, though the new approach tends to give values by about 4%-5% higher than the reference method. On the average, the solution of the coupled perturbed equations with the new scheme is about 8.5 times faster compared to the reference method.
Interface driven magnetic interactions in nanostructured thin films of iron nanocrystallites embedded in a copper matrix
Authors: Desautels R. D. , Shueh C. , Lin K.-W. , Freeland J. W. , van Lierop J.
Published: March 2015

We have fabricated thin films of iron nanocrystallites embedded in a copper matrix using a dual ion beam assisted deposition technique. A secondary End-Hall ion beam bombarded the iron atoms during deposition altering significantly the morphology of the films and allowing for control of the intermixing between iron and copper components. Cross-sectional transmission electron microscopy and x-ray reflectometry experiments indicated that the morphology of the films was that of iron nanocrystallites embedded in a copper matrix. Rietveld refinements of the diffraction pattern identified fcc-copper and amorphous iron. An increased amount of disorder was observed with a reduction in the amount of deposited iron from a 1:1 Fe:Cu ratio to 0.25:0.75 Fe:Cu ratio. Interfacial copper-iron alloys were identified by DC susceptibility experiments through their reduced TC,Alloy (370, 310, and 280 K) compared with that of bulk iron (∼1000 K). Element specific x-ray absorption and x-ray magnetic circular dichroism experiments were performed to identify the contributions to the magnetism from the iron and the copper-iron alloy.
Chain architecture and micellization: A mean-field coarse-grained model for poly(ethylene oxide) alkyl ether surfactants
Authors: García Daza Fabián A. , Colville Alexander J. , Mackie Allan D.
Published: March 2015

Microscopic modeling of surfactant systems is expected to be an important tool to describe, understand, and take full advantage of the micellization process for different molecular architectures. Here, we implement a single chain mean field theory to study the relevant equilibrium properties such as the critical micelle concentration (CMC) and aggregation number for three sets of surfactants with different geometries maintaining constant the number of hydrophobic and hydrophilic monomers. The results demonstrate the direct effect of the block organization for the surfactants under study by means of an analysis of the excess energy and entropy which can be accurately determined from the mean-field scheme. Our analysis reveals that the CMC values are sensitive to branching in the hydrophilic head part of the surfactant and can be observed in the entropy-enthalpy balance, while aggregation numbers are also affected by splitting the hydrophobic tail of the surfactant and are manifested by slight changes in the packing entropy.
Voltage modulation of propagating spin waves in Fe
Authors: Nawaoka Kohei , Shiota Yoichi , Miwa Shinji , Tomita Hiroyuki , Tamura Eiiti , Mizuochi Norikazu , Shinjo Teruya , Suzuki Yoshishige
Published: March 2015

The effect of a voltage application on propagating spin waves in single-crystalline 5 nm-Fe layer was investigated. Two micro-sized antennas were employed to excite and detect the propagating spin waves. The voltage effect was characterized using AC lock-in technique. As a result, the resonant field of the magnetostatic surface wave in the Fe was clearly modulated by the voltage application. The modulation is attributed to the voltage induced magnetic anisotropy change in ferromagnetic metals.
Attenuation of short stress pulses in strongly nonlinear dissipative metamaterial
Authors: Xu Yichao , Nesterenko Vitali F.
Published: March 2015

Attenuation of short stress pulses under different levels of precompression was investigated in a one-dimensional strongly nonlinear discrete metamaterial assembled using alternating steel disks and toroidal Nitrile O-rings. The results were compared with the numerical modeling. A double power-law is used to describe the nonlinear interaction between the disks due to the compression of rubber O-rings. The dispersion behavior caused by the periodic arrangement of elements is contributing to the attenuation of pulse, but could not explain the experimental observations. It was explained by taking into account the nonlinear viscous behavior of O-rings. The numerical simulations were able to predict the dependence of the signal speed on the precompression force, a significant decrease of the pulse width with the precompression and the attenuation of the leading positive pulse, the latter of major significance in the protection against impact. This strongly nonlinear dissipative metamaterial has a potential for attenuation of dynamic loading and allows an enhanced tunability of signal speed and degree of attenuation.
Infrared spectroscopy of the methanol cation and its methylene-oxonium isomer
Authors: Mosley J. D. , Young J. W. , Huang M. , McCoy A. B. , Duncan M. A.
Published: March 2015

The carbenium ion with nominal formula [C,H4,O]+ is produced from methanol or ethylene glycol in a pulsed-discharge supersonic expansion source. The ion is mass selected, and its infrared spectrum is measured from 2000 to 4000 cm−1 using laser photodissociation spectroscopy and the method of rare gas atom tagging. Computational chemistry predicts two isomers, the methanol and methylene-oxonium cations. Predicted vibrational spectra based on scaled harmonic and reduced dimensional treatments are compared to the experimental spectra. The methanol cation is the only isomer produced when methanol is used as a precursor. When ethylene glycol is used as the precursor, methylene-oxonium is produced in addition to the methanol cation. Theoretical results at the CCSD(T)/cc-pVTZ level show that methylene-oxonium is lower in energy than methanol cation by 6.4 kcal/mol, and is in fact the global minimum isomer on the [C,H4,O]+ potential surface. Methanol cation is trapped behind an isomerization barrier in our source, providing a convenient method to produce and characterize this transient species. Analysis of the spectrum of the methanol cation provides evidence for strong CH stretch vibration/torsion coupling in this molecular ion.
One-electron reduced density matrices of strongly correlated harmonium atoms
Authors: Cioslowski Jerzy
Published: March 2015

Explicit asymptotic expressions are derived for the reduced one-electron density matrices (the 1-matrices) of strongly correlated two- and three-electron harmonium atoms in the ground and first excited states. These expressions, which are valid at the limit of small confinement strength ω, yield electron densities and kinetic energies in agreement with the published values. In addition, they reveal the ω5/6 asymptotic scaling of the exchange components of the electron-electron repulsion energies that differs from the ω2/3 scaling of their Coulomb and correlation counterparts. The natural orbitals of the totally symmetric ground state of the two-electron harmonium atom are found to possess collective occupancies that follow a mixed power/Gaussian dependence on the angular momentum in variance with the simple power-law prediction of Hill’s asymptotics. Providing rigorous constraints on energies as functionals of 1-matrices, these results are expected to facilitate development of approximate implementations of the density matrix functional theory and ensure their proper description of strongly correlated systems.
Iterative universal state selective correction for the Brillouin-Wigner multireference coupled-cluster theory
Authors: Banik Subrata , Ravichandran Lalitha , Brabec Jiří , Hubač Ivan , Kowalski Karol , Pittner Jiří
Published: March 2015

As a further development of the previously introduced a posteriori Universal State-Selective (USS) corrections [K. Kowalski, J. Chem. Phys. 134, 194107 (2011); J. Brabec et al., ibid. 136, 124102 (2012)], we suggest an iterative form of the USS correction by means of correcting effective Hamiltonian matrix elements. We also formulate USS corrections via the left Bloch equations. The convergence of the USS corrections with excitation level towards the full configuration interaction (FCI) limit is also investigated. Various forms of the USS and simplified diagonal USS corrections at the singles and doubles and perturbative triple levels are numerically assessed on several model systems and on the ozone and tetramethyleneethane molecules. It is shown that the iterative USS correction can successfully replace the previously developed a posteriori Brillouin-Wigner coupled cluster size-extensivity correction, while it is not sensitive to intruder states and performs well also in other cases when the a posteriori one fails, like, e.g., for the asymmetric vibration mode of ozone.
Kinetic Monte Carlo study of triplet-triplet annihilation in organic phosphorescent emitters
Authors: van Eersel H. , Bobbert P. A. , Coehoorn R.
Published: March 2015

The triplet-triplet annihilation (TTA) rate in organic phosphorescent materials such as used in organic light-emitting diodes is determined predominantly either by the rate of single-step Förster-type triplet-triplet interactions, or by multi-step triplet diffusion. We show how kinetic Monte Carlo simulations may be used to analyze the role of both processes. Under steady state conditions, the effective triplet-triplet interaction rate coefficient, kTT, which is often regarded as a constant, is found to depend actually on the number of excitons lost upon a triplet-triplet interaction process and to show a significant higher-order dependence on the triplet volume density. Under the conditions encountered in transient photoluminescence (PL) studies, kTT is found to be effectively constant in the case of diffusion-dominated TTA. However, for the case of single-step TTA, a strongly different decay of the emission intensity is found, which also deviates from an analytic expression proposed in the literature. We discuss how the transient PL response may be used to make a distinction between both mechanisms. The simulations are applied to recently published work on the dye concentration dependence of the TTA rate in materials based on the archetypal green emitter tris[2-phenylpyridine]iridium (Ir(ppy)3).
Flexible attosecond beamline for high harmonic spectroscopy and XUV/near-IR pump probe experiments requiring long acquisition times
Authors: Weber S. J. , Manschwetus B. , Billon M. , Böttcher M. , Bougeard M. , Breger P. , Géléoc M. , Gruson V. , Huetz A. , Lin N. , Picard Y. J. , Ruchon T. , Salières P. , Carré B.
Published: March 2015

We describe the versatile features of the attosecond beamline recently installed at CEA-Saclay on the PLFA kHz laser. It combines a fine and very complete set of diagnostics enabling high harmonic spectroscopy (HHS) through the advanced characterization of the amplitude, phase, and polarization of the harmonic emission. It also allows a variety of photo-ionization experiments using magnetic bottle and COLTRIMS (COLd Target Recoil Ion Momentum Microscopy) electron spectrometers that may be used simultaneously, thanks to a two-foci configuration. Using both passive and active stabilization, special care was paid to the long term stability of the system to allow, using both experimental approaches, time resolved studies with attosecond precision, typically over several hours of acquisition times. As an illustration, applications to multi-orbital HHS and electron-ion coincidence time resolved spectroscopy are presented.
Combinatorial thin film composition mapping using three dimensional deposition profiles
Authors: Suram Santosh K. , Zhou Lan , Becerra-Stasiewicz Natalie , Kan Kevin , Jones Ryan J. R. , Kendrick Brian M. , Gregoire John M.
Published: March 2015

Many next-generation technologies are limited by material performance, leading to increased interest in the discovery of advanced materials using combinatorial synthesis, characterization, and screening. Several combinatorial synthesis techniques, such as solution based methods, advanced manufacturing, and physical vapor deposition, are currently being employed for various applications. In particular, combinatorial magnetron sputtering is a versatile technique that provides synthesis of high-quality thin film composition libraries. Spatially addressing the composition of these thin films generally requires elemental quantification measurements using techniques such as energy-dispersive X-ray spectroscopy or X-ray fluorescence spectroscopy. Since these measurements are performed ex-situ and post-deposition, they are unable to provide real-time design of experiments, a capability that is required for rapid synthesis of a specific composition library. By using three quartz crystal monitors attached to a stage with translational and rotational degrees of freedom, we measure three-dimensional deposition profiles of deposition sources whose tilt with respect to the substrate is robotically controlled. We exhibit the utility of deposition profiles and tilt control to optimize the deposition geometry for specific combinatorial synthesis experiments.
An ion trap built with photonic crystal fibre technology
Authors: Lindenfelser F. , Keitch B. , Kienzler D. , Bykov D. , Uebel P. , Schmidt M. A. , Russell P. St. J. , Home J. P.
Published: March 2015

We demonstrate a surface-electrode ion trap fabricated using techniques transferred from the manufacture of photonic-crystal fibres. This provides a relatively straightforward route for realizing traps with an electrode structure on the 100 micron scale with high optical access. We demonstrate the basic functionality of the trap by cooling a single ion to the quantum ground state, allowing us to measure a heating rate from the ground state of 787 ± 24 quanta/s. Variation of the fabrication procedure used here may provide access to traps in this geometry with trap scales between 100 μm and 10 μm.
A compact time-of-flight mass spectrometer for ion source characterization
Authors: Chen L. , Wan X. , Jin D. Z. , Tan X. H. , Huang Z. X. , Tan G. B.
Published: March 2015

A compact time-of-flight mass spectrometer with overall dimension of about 413 × 250 × 414 mm based on orthogonal injection and angle reflection has been developed for ion source characterization. Configuration and principle of the time-of-flight mass spectrometer are introduced in this paper. The mass resolution is optimized to be about 1690 (FWHM), and the ion energy detection range is tested to be between about 3 and 163 eV with the help of electron impact ion source. High mass resolution and compact configuration make this spectrometer useful to provide a valuable diagnostic for ion spectra fundamental research and study the mass to charge composition of plasma with wide range of parameters.
Dynamical programming based turbulence velocimetry for fast visible imaging of tokamak plasma
Authors: Banerjee Santanu , Zushi H. , Nishino N. , Mishra K. , Onchi T. , Kuzmin A. , Nagashima Y. , Hanada K. , Nakamura K. , Idei H. , Hasegawa M. , Fujisawa A.
Published: March 2015

An orthogonal dynamic programming (ODP) based particle image velocimetry (PIV) technique is developed to measure the time resolved flow field of the fluctuating structures at the plasma edge and scrape off layer (SOL) of tokamaks. This non-intrusive technique can provide two dimensional velocity fields at high spatial and temporal resolution from a fast framing image sequence and hence can provide better insights into plasma flow as compared to conventional probe measurements. Applicability of the technique is tested with simulated image pairs. Finally, it is applied to tangential fast visible images of QUEST plasma to estimate the SOL flow in inboard poloidal null–natural divertor configuration. This technique is also applied to investigate the intricate features of the core of the run-away dominated phase following the injection of a large amount of neutrals in the target Ohmic plasma. Development of the ODP-PIV code and its applicability on actual plasma images is reported.
A standing wave linear ultrasonic motor operating in in-plane expanding and bending modes
Authors: Chen Zhijiang , Li Xiaotian , Ci Penghong , Liu Guoxi , Dong Shuxiang
Published: March 2015

A novel standing wave linear ultrasonic motor operating in in-plane expanding and bending modes was proposed in this study. The stator (or actuator) of the linear motor was made of a simple single Lead Zirconate Titanate (PZT) ceramic square plate (15 × 15 × 2 mm3) with a circular hole (D = 6.7 mm) in the center. The geometric parameters of the stator were computed with the finite element analysis to produce in-plane bi-mode standing wave vibration. The calculated results predicted that a driving tip attached at midpoint of one edge of the stator can produce two orthogonal, approximate straight-line trajectories, which can be used to move a slider in linear motion via frictional forces in forward or reverse direction. The investigations showed that the proposed linear motor can produce a six times higher power density than that of a previously reported square plate motor.
High-pressure generation using double stage micro-paired diamond anvils shaped by focused ion beam
Authors: Sakai Takeshi , Yagi Takehiko , Ohfuji Hiroaki , Irifune Tetsuo , Ohishi Yasuo , Hirao Naohisa , Suzuki Yuya , Kuroda Yasushi , Asakawa Takayuki , Kanemura Takashi
Published: March 2015

Micron-sized diamond anvils with a 3 μm culet were successfully processed using a focused ion beam (FIB) system and the generation of high pressures was confirmed using the double stage diamond anvil cell technique. The difficulty of aligning two second-stage micro-anvils was solved via the paired micro-anvil method. Micro-manufacturing using a FIB system enables us to control anvil shape, process any materials, including nano-polycrystalline diamond and single crystal diamond, and assemble the sample exactly in a very small space between the second-stage anvils. This method is highly reproducible. High pressures over 300 GPa were achieved, and the pressure distribution around the micro-anvil culet was evaluated by using a well-focused synchrotron micro-X-ray beam.
Explosively driven air blast in a conical shock tube
Authors: Stewart Joel B. , Pecora Collin
Published: March 2015

Explosively driven shock tubes present challenges in terms of safety concerns and expensive upkeep of test facilities but provide more realistic approximations to the air blast resulting from free-field detonations than those provided by gas-driven shock tubes. Likewise, the geometry of conical shock tubes can naturally approximate a sector cut from a spherically symmetric blast, leading to a better agreement with the blast profiles of free-field detonations when compared to those provided by shock tubes employing constant cross sections. The work presented in this article documents the design, fabrication, and testing of an explosively driven conical shock tube whose goal was to closely replicate the blast profile seen from a larger, free-field detonation. By constraining the blast through a finite area, large blasts (which can add significant damage and safety constraints) can be simulated using smaller explosive charges. The experimental data presented herein show that a close approximation to the free-field air blast profile due to a 1.5 lb charge of C4 at 76 in. can be achieved by using a 0.032 lb charge in a 76-in.-long conical shock tube (which translates to an amplification factor of nearly 50). Modeling and simulation tools were used extensively in designing this shock tube to minimize expensive fabrication costs.
Universal quantum computation with metaplectic anyons
Authors: Cui Shawn X. , Wang Zhenghan
Published: March 2015

We show that braidings of the metaplectic anyons Xϵ in SO(3)2 = SU(2)4 with their total charge equal to the metaplectic mode Y supplemented with projective measurements of the total charge of two metaplectic anyons are universal for quantum computation. We conjecture that similar universal anyonic computing models can be constructed for all metaplectic anyon systems SO(p)2 for any odd prime p ≥ 5. In order to prove universality, we find new conceptually appealing universal gate sets for qutrits and qupits.
Sub-nA spatially resolved conductivity profiling of surface and interface defects in ceria films
Authors: Farrow Tim , Yang Nan , Doria Sandra , Belianinov Alex , Jesse Stephen , Arruda Thomas M. , Balestrino Giuseppe , Kalinin Sergei V. , Kumar Amit
Published: March 2015

Spatial variability of conductivity in ceria is explored using scanning probe microscopy with galvanostatic control. Ionically blocking electrodes are used to probe the conductivity under opposite polarities to reveal possible differences in the defect structure across a thin film of CeO2. Data suggest the existence of a large spatial inhomogeneity that could give rise to constant phase elements during standard electrochemical characterization, potentially affecting the overall conductivity of films on the macroscale. The approach discussed here can also be utilized for other mixed ionic electronic conductor systems including memristors and electroresistors, as well as physical systems such as ferroelectric tunneling barriers.
Mechanics of drag reduction by shallow dimples in channel flow
Authors: Tay C. M. J. , Khoo B. C. , Chew Y. T.
Published: March 2015

Arrays of shallow dimples with depth to diameter ratios of 1.5% and 5% are studied in a turbulent channel flow at Reynolds numbers between 5000 and 35 000. Pressure measurements show that drag reduction of up to 3% is possible. The mechanism of skin friction drag reduction with dimples is the same as that observed for flat surfaces using active methods such as spanwise wall motions or transverse wall jets. The three dimensional dimples introduce streamwise vorticity into the flow which results in spanwise flow components near the wall. The result is that the normal energy cascade to the smaller scales is suppressed, which leads to a reduction in turbulent skin friction drag because of the stabilized flow. Increasing the dimple depth from 1.5% to 5% of its diameter increases the streamwise vorticity introduced, which leads to a greater reduction in skin friction. However, increasing the dimple depth also results in flow separation which increases form drag. The net effect to the total drag depends on the relative dominance between the drag reducing streamwise vorticity and the drag increasing flow separation region. As the Reynolds number increases, the region of flow separation can shrink and result in increasing drag reduction. By understanding the flow physics of drag reduction in dimples, there is opportunity to minimize the form drag by passive contouring of the dimples using non-spherical shapes to optimize the dimple performance.
Note: Self-biased magnetic field sensor using end-bonding magnetoelectric heterostructure
Authors: Zhao Yaoxia , Lu Caijiang
Published: March 2015

A high sensitivity magnetic field sensor based on magnetoelectric (ME) coupling is presented. The ME sensor FeCuNbSiB/Nickel-PZT-FeCuNbSiB/Nickel is made by bonding magnetization-graded magnetostrictive materials FeCuNbSiB/Nickel at the free ends of the piezoelectric Pb(Zr1−x,Tix)O3 (PZT) plate. Experiments indicate that the proposed sensor has a zero-bias field sensitivity of 14.7 V/Oe at resonance, which is ∼41.6 times larger than that of previous FeCuNbSiB-PZT-FeCuNbSiB. Furthermore, without external biased field, it can detect dc magnetic field changes as small as ∼9 nT near the resonant frequency. This proposed ME sensor provides new pathways to reducing or even eliminating the need of bias fields for ME sensors.
Dielectric anomalies due to grain boundary conduction in chemically substituted BiFeO3
Authors: Kumari Shalini , Ortega N. , Kumar A. , Pavunny S. P. , Hubbard J. W. , Rinaldi C. , Srinivasan G. , Scott J. F. , Katiyar Ram S.
Published: March 2015

We describe systematic studies on Nd and Mn co-doped BiFeO3, i.e., (Bi0.95Nd0.05)(Fe0.97Mn0.03)O3 (BNFM) polycrystalline electroceramics. Raman spectra and X-ray diffraction patterns revealed the formation of rhombohedral crystal structure at room temperature, and ruled out structural changes in BiFeO3 (BFO) after low percentage chemical substitution. Strong dielectric dispersion and a sharp anomaly around 620 K observed near the Néel temperature (TN ∼ 643 K of BFO) support strong magneto-dielectric coupling, verified by the exothermic peak in differential thermal data. Impedance spectroscopy disclosed the appearance of grain boundary contributions in the dielectric data in the region, and their disappearance just near the Néel temperature suggests magnetically active grain boundaries. The resistive grain boundary components of the BNFM are mainly responsible for magneto-dielectric coupling. Capacitive grain boundaries are not observed in the modulus spectra and the dielectric behavior deviates from the ideal Debye-type. The ac conduction studies illustrate short-range order with ionic translations assisted by both large and small polaron hopping. Magnetic studies indicate that the weak antiferromagnetic phase of BNFM ceramics is dominated by a strong paramagnetic response (unsaturated magnetization even at applied magnetic field of 7 T). The bulk BNFM sample shows a good in-plane magnetoelectric coupling (ME) coefficient.
Space charge effects for multipactor in coaxial lines
Authors: Sorolla E. , Sounas A. , Mattes M.
Published: March 2015

Multipactor is a hazardous vacuum discharge produced by secondary electron emission within microwave devices of particle accelerators and telecommunication satellites. This work analyzes the dynamics of the multipactor discharge within a coaxial line for the mono-energetic electron emission model taking into account the space charge effects. The steady-state is predicted by the proposed model and an analytical expression for the maximum number of electrons released by the discharge presented. This could help to link simulations to experiments and define a multipactor onset criterion.
Phase sensitive Raman process with correlated seeds
Authors: Chen Bing , Qiu Cheng , Chen L. Q. , Zhang Kai , Guo Jinxian , Yuan Chun-Hua , Ou Z. Y. , Zhang Weiping
Published: March 2015

A phase sensitive Raman scattering was experimentally demonstrated by injecting a Stokes light seed into an atomic ensemble, whose internal state is set in such a way that it is coherent with the input Stokes seed. Such phase sensitive characteristic is a result of interference effect due to the phase correlation between the injected Stokes light field and the internal state of the atomic ensemble in the Raman process. Furthermore, the constructive interference leads to a Raman efficiency larger than other kinds of Raman processes such as stimulated Raman process with Stokes seed injection alone or uncorrelated light-atom seeding. It may find applications in precision spectroscopy, quantum optics, and precise measurement.
Compact silicon photonic wavelength-tunable laser diode with ultra-wide wavelength tuning range
Authors: Kita Tomohiro , Tang Rui , Yamada Hirohito
Published: March 2015

We present a wavelength-tunable laser diode with a 99-nm-wide wavelength tuning range. It has a compact wavelength-tunable filter with high wavelength selectivity fabricated using silicon photonics technology. The silicon photonic wavelength-tunable filter with wide wavelength tuning range was realized using two ring resonators and an asymmetric Mach-Zehnder interferometer. The wavelength-tunable laser diode fabricated by butt-joining a silicon photonic filter and semiconductor optical amplifier shows stable single-mode operation over a wide wavelength range.
Hybrid superconducting neutron detectors
Authors: Merlo V. , Salvato M. , Cirillo M. , Lucci M. , Ottaviani I. , Scherillo A. , Celentano G. , Pietropaolo A.
Published: March 2015

A neutron detection concept is presented that is based on superconductive niobium (Nb) strips coated by a boron (B) layer. The working principle of the detector relies on the nuclear reaction, 10B + n → α + 7Li, with α and Li ions generating a hot spot on the current-biased Nb strip which in turn induces a superconducting-normal state transition. The latter is recognized as a voltage signal which is the evidence of the incident neutron. The above described detection principle has been experimentally assessed and verified by irradiating the samples with a pulsed neutron beam at the ISIS spallation neutron source (UK). It is found that the boron coated superconducting strips, kept at a temperature T = 8 K and current-biased below the critical current Ic, are driven into the normal state upon thermal neutron irradiation. As a result of the transition, voltage pulses in excess of 40 mV are measured while the bias current can be properly modulated to bring the strip back to the superconducting state, thus resetting the detector. Measurements on the counting rate of the device are presented and the basic physical features of the detector are discussed.
Electronic heat current rectification in hybrid superconducting devices
Authors: Fornieri Antonio , Martínez-Pérez María José , Giazotto Francesco
Published: March 2015

In this work, we review and expand recent theoretical proposals for the realization of electronic thermal diodes based on tunnel-junctions of normal metal and superconducting thin films. Starting from the basic rectifying properties of a single hybrid tunnel junction, we will show how the rectification efficiency can be largely increased by combining multiple junctions in an asymmetric chain of tunnel-coupled islands. We propose three different designs, analyzing their performance and their potential advantages. Besides being relevant from a fundamental physics point of view, this kind of devices might find important technological application as fundamental building blocks in solid-state thermal nanocircuits and in general-purpose cryogenic electronic applications requiring energy management.
Effects of local testicular heat treatment on Leydig cell hyperplasia and testosterone biosynthesis in rat testes
Authors: Li Zhonghai , Tian Jianhai , Cui Genggang , Wang Meng , Yu Dapeng
Published: March 2015

Cryptorchidism or local testicular heat treatment induces reversible oligospermia or azoospermia in rodents and humans via increased germ cell apoptosis. Research in this field has concentrated on the impact of heat on spermatogenesis, with rather little attention paid to the molecular effects of heat treatment on Leydig cell function. In the present study, we investigated the effects of exposure to heat stress on the proliferative activity and testosterone biosynthesis of Leydig cells. We subjected adult rats to a single local testicular heat treatment of water at 43°C for 30 min. The expression of Leydig cell-specific markers, such as cholesterol side-chain cleavage (P450SCC) and 3β-hydroxysteroid dehydrogenase, was evaluated by immunohistochemistry and western blot analysis. The proliferative activity of Leydig cells was detected by immunostaining with proliferation-associated markers, including Ki67, bromodeoxyuridine and phosphohistone-H3 (pHH3). The mRNA and protein levels of cell cycle proteins and testosterone synthesis-related enzymes were measured by real-time polymerase chain reaction and western blot analysis, respectively. The testes of heat-treated rats contained 50% more Leydig cells than those of control rats, indicating induction of Leydig cell hyperplasia by testicular heat treatment. Increased proliferative activity in Leydig cells, evidenced by enhanced expression of cell cycle proteins, was the main cause of Leydig cell hyperplasia. In addition, heat treatment reduced serum and testicular testosterone concentrations. Consistent with this finding, heat stress downregulated two enzymes required for testosterone biosynthesis, namely cytochrome P450, family 17 (CYP17) and steroidogenic acute regulatory protein, in Leydig cells. Together, the results suggest that testicular heat leads to Leydig cell hyperplasia and a reduction in testosterone biosynthesis in adult rat testes.
PAB is an assembly chaperone that functions downstream of chaperonin 60 in the assembly of chloroplast ATP synthase coupling factor 1
Authors: Mao Juan , Chi Wei , Ouyang Min , He Baoye , Chen Fan , Zhang Lixin
Published: March 2015

Significance

The assembly of chloroplast ATP synthase, a multiprotein complex made of subunits of mixed genetic origin, is essential for organelle biogenesis and organism survival. Assembly of multiprotein complexes relies not only on the proper action of universal folding chaperones but also on that of specific assembly chaperones that orchestrate the joining of individual components into higher-order complexes. In this work, we have identified a specific assembly chaperone for chloroplast ATP synthase and shown that it functions downstream of the Cpn60 chaperone to promote assembly of the catalytically active core of the chloroplast ATP synthase. Such collaboration between folding and assembly chaperones appears to be a widely used cellular strategy for the folding and assembly of nucleus-encoded proteins into multiprotein photosynthetic complexes.