bluuebunny/crossref_metadata_2025 huggingface dataset:
Confocal absorption spectral imaging of MoS2: optical transitions depending on the atomic thickness of intrinsic and chemically doped MoS2
Authors: Dhakal Krishna P. , Duong Dinh Loc , Lee Jubok , Nam Honggi , Kim Minsu , Kan Min , Lee Young Hee , Kim Jeongyong
Published: September 2014

Absorption spectral maps of MoS2 show the variation of optical transitions depending on the atomic thickness and the chemical doping.
Facile synthesis of gold nanoworms with a tunable length and aspect ratio through oriented attachment of nanoparticles
Authors: Ahmed Waqqar , Glass Christian , van Ruitenbeek Jan M.
Published: September 2014

We report a seedless protocol based on the oriented attachment of nanoparticles for the synthesis of Au nanoworms (NWs).
Perovskite photovoltaics: a high-efficiency newcomer to the solar cell family
Authors: Wang Baohua , Xiao Xudong , Chen Tao
Published: September 2014

This minireview comments on the development and potential impact of perovskite solar cells on the solar cell family.
Where is the required lattice match in horizontal growth of nanowires?
Authors: Nikoobakht Babak , Herzing Andrew
Published: September 2014

In metal-catalyzed horizontal growth of nanowires, our results show that the lattice match with substrate exists along the width of the nanowire and not its length. This finding is in contrast with what has been observed in the traditional planar growth of nanowires and could be used for fine tuning the nanowire structure at nanoscale.
Separation of binary solvent mixtures with solvent resistant nanofiltration membranes Part A: investigation of separation performance
Authors: Li Jiandong , Wang Miaomiao , Huang Yucui , Luo Beibei , Zhang Yuan , Yuan Qipeng
Published: September 2014

This paper is Part A of a two paper series seeking a systematical investigation of the feasibility of separating binary solvent mixtures with solvent resistant nanofiltration (SRNF) membranes.
Polyimide nanocomposites with functionalized SiO2 nanoparticles: enhanced processability, thermal and mechanical properties
Authors: Kim Young-Jae , Kim Jong-Heon , Ha Shin-Woo , Kwon Dongil , Lee Jin-Kyu
Published: September 2014

SiO2–polyimide nanocomposites having enhanced processability, thermal and mechanical properties were easily fabricated by the surface modification of silica nanoparticles with functional groups having chemical and structural similarity to polyimide chain.
Two dimensional TiO2nanosheets: in vivo toxicity investigation
Authors: Song Sha-Sha , Xia Bao-Yu , Chen Jie , Yang Jiang , Shen Xiu , Fan Sai-Jun , Guo Mei-li , Sun Yuan-Ming , Zhang Xiao-Dong
Published: September 2014

Titanium dioxide (TiO2) nanosheets have received attention for photodynamic therapy due to their unique electronic structure and high surface activity.
Amide-imide tautomerism of acetohydroxamic acid in aqueous solution: quantum calculation and SMD simulations
Authors: Tolosa S. , Mora-Diez N. , Hidalgo A. , Sansón J. A.
Published: September 2014

The kinetics and the thermodynamics of the amide-imide tautomerizations of acetohydroxamic acid in aqueous solution are studied from a theoretical point of view.
Aquatic biomass containing porous silica as an anode for lithium ion batteries
Authors: Lisowska-Oleksiak Anna , Nowak Andrzej P. , Wicikowska Beata
Published: September 2014

A composite electrode was manufactured by pyrolysis of Red Algae (Polysiphonia fucoides) covered by diatoms (Diatomophyceae).
QSPR with descriptors based on averages of vertex invariants. An artificial neural network study
Authors: Pogliani Lionello , Vicente de Julián-Ortiz Jesus
Published: September 2014

Mean molecular connectivity indices (MMCI) defined as averages of vertex invariants together with molecular connectivity indices (MCI) and experimental parameters build optimal semiempirical relationships for eight out of eleven properties of organic solvents studied with artificial neural networks.
Continuous-flow synthesis of polymer nanoparticles in a microreactor via miniemulsion photopolymerization
Authors: Lobry Emeline , Jasinski Florent , Penconi Marta , Chemtob Abraham , Croutxé-Barghorn Céline , Oliveros Esther , Braun André M. , Criqui Adrien
Published: September 2014

Water-based photopolymerization in microreactor using compact UV fluorescent lamps can create a breakthrough technology to produce polymer latexes in a safer, more environmental-friendly and energy-efficient way.
Photochemical induced formed Au nanomaterial with size and shape controlled by luminol–pepsin chemiluminescence reaction
Authors: Luo Kai , Zheng Xiaohui , Song Zhenghua
Published: September 2014

The different size and shape AuNMs were generated in the Pep–HAuCl4 system based on the photochemical induced effect of alkaline luminol.
Oxygen as single oxidant for two steps: base-free one-pot Pd(ii)-catalyzed alcohol oxidation & arylation to halogen-intact β-aryl α,β-enones
Authors: Vellakkaran Mari , Andappan Murugaiah M. S. , Nagaiah Kommu
Published: September 2014

Using oxygen as the sole oxidant for two steps, we developed a new method to synthesize β-aryl α,β-enones by fine-tuning the Pd(ii)-catalyzed oxidation of allyl alcohol to subsequent arylation with arylboronic acids, arylboronic ester and aryltrifluoroborate salt.
Red fluorescent hybrid mesoporous organosilicas for simultaneous cell imaging and anticancer drug delivery
Authors: Moorthy Madhappan Santha , Song Hyun-Jin , Bae Jae-Ho , Kim Sun-Hee , Ha Chang-Sik
Published: September 2014

Red fluorescent mesoporous organosilica was synthesised for simultaneous diagnosis and therapy, and characterized for anticancer drug delivery behavior.
Internal friction characteristic and analysis of in-plane natural frequency of trilayer complexes formed from graphenes and boron nitride nanosheets
Authors: Yuan Jianhui , Liew K. M.
Published: September 2014

The internal friction and in-plane natural frequency of a trilayer complex formed by a monolayer graphene sandwiched in the bilayer of boron nitride nanosheets (BN/G/BN) and graphenes (G/G/G) are studied by using molecular dynamics.
Education for sustainable development in chemistry – challenges, possibilities and pedagogical models in Finland and elsewhere
Authors: Juntunen M. K. , Aksela M. K.
Published: September 2014

This article analyses Education for Sustainable Development (ESD) in chemistry by reviewing existing challenges and future possibilities on the levels of the teacher and the student. Pedagogical frameworks that are found eligible in practice are reviewed. Lesson themes that are suitable for implementing socio-scientific issues (SSI) related to ESD into basic chemistry education at schools are discussed. Based on this analysis, three new demonstrative pedagogical models for ESD in chemistry are presented to help guide the work of teachers. The models draw on an interdisciplinary reading of research in the field of SSI-based science education, sustainability science, green chemistry and environmental education. The current state of ESD in Finnish chemistry education is used as an example case throughout the article. Two tasks where future development is required were recognised. The first task concerns supporting chemistry teachers in overcoming the challenges with SSI and ESD they face in their work. The second task is to ensure that students are more often provided with more relevant and flexible chemistry content and studying methods.
Thin film fabrication and characterization of proton conducting lanthanum tungstate
Authors: Bergum Kristin , Magrasó Anna , Fjellvåg Helmer , Nilsen Ola
Published: September 2014

Thin films of the proton conducting lanthanum tungstate phase, La28−xW4+xO54+δv2−δ, were fabricated by atomic layer deposition (ALD) and characterized by impedance spectroscopy.
Revisiting Li3V2(PO4)3as an anode – an outstanding negative electrode for high power energy storage devices
Authors: Zhang Xiaofei , Kühnel Ruben-Simon , Schroeder Matthias , Balducci Andrea
Published: September 2014

A carbon coated Li3V2(PO4)3nanomaterial obtained by an ionic liquid-assisted synthesis is presented as an excellent negative electrode material for high power energy storage devices.
Charge compensation in RE3+ (RE = Eu, Gd) and M+ (M = Li, Na, K) co-doped alkaline earth nanofluorides obtained by microwave reaction with reactive ionic liquids leading to improved optical properties
Authors: Lorbeer C. , Behrends F. , Cybinska J. , Eckert H. , Mudring A.-V.
Published: September 2014

Careful charge compensation in doubly doped alkaline earth nanofluorides enables a luminescent material with 199% quantum yield.
Interpenetrating morphology based on highly crystalline small molecule and PCBM blends
Authors: Liu Feng , Zhang Lei , Zhang Yue , Mannsfeld Stefan C. B. , Russell Thomas P. , Briseno Alejandro L.
Published: September 2014

Processing solvent has profound effect on the morphology of small molecule based organic photovoltaics.
Plasmonic enhancement of dual mode fluorescence in a silver nano-antenna–ZnO:Er3+ hybrid nanostructure
Authors: Das Rupali , Phadke Parikshit , Khichar Naveen , Chawla Santa
Published: September 2014

Plasmonic enhancement of dual mode fluorescence in Er3+–doped ZnO nanoparticles by shape tailored Ag nanoparticles.
CaY2Si2S8:Ce3+: a novel green-emitting thiosilicate phosphor for white light-emitting diodes
Authors: Lee Szu-Ping , Huang Chien-Hao , Chen Teng-Ming
Published: September 2014

The luminescence of a green-emitting CaY2Si2S8:Ce3+ phosphor and its applicability in fabrication of white LEDs with high CRI and varied CCTs were explored.
Reversible vapochromic response of polymer films doped with a highly emissive molecular rotor
Authors: Minei Pierpaolo , Koenig Matthias , Battisti Antonella , Ahmad Muzaffer , Barone Vincenzo , Torres Tomas , Guldi Dirk M. , Brancato Giuseppe , Bottari Giovanni , Pucci Andrea
Published: September 2014

The reversible, vapochromic response of polymeric films doped with a 4-(diphenylamino)phthalonitrile (DPAP) fluorescent molecular rotor suitable for sensing volatile organic compounds (VOCs) is presented.
The antimicrobial peptide LL-37 facilitates the formation of neutrophil extracellular traps
Authors: Neumann Ariane , Berends Evelien T. M. , Nerlich Andreas , Molhoek E. Margo , Gallo Richard L. , Meerloo Timo , Nizet Victor , Naim Hassan Y. , von Köckritz-Blickwede Maren
Published: September 2014

NETs (neutrophil extracellular traps) have been described as a fundamental innate immune defence mechanism. During formation of NETs, the nuclear membrane is disrupted by an as-yet unknown mechanism. In the present study we investigated the role of human cathelicidin LL-37 in nuclear membrane disruption and formation of NETs. Immunofluorescence microscopy revealed that 5 μM LL-37 significantly facilitated NET formation by primary human blood-derived neutrophils alone, in the presence of the classical chemical NET inducer PMA or in the presence of Staphylococcus aureus. Parallel assays with a random LL-37 fragment library indicated that the NET induction is mediated by the hydrophobic character of the peptide. The trans-localization of LL-37 towards the nucleus and the disruption of the nuclear membrane were visualized using confocal fluorescence microscopy. In conclusion, the present study demonstrates a novel role for LL-37 in the formation of NETs.
Risk of supply insecurity with weather condition‐based operation of plug in hybrid electric vehicles
Authors: Jayaweera Dilan , Islam Syed
Published: September 2014

Plug in hybrid electric vehicles (PHEVs) can be a strategic source to mitigate risk of supply insecurity in an active distribution network. This study proposes a new methodology to quantify the risk of supply insecurity with weather condition based operation of PHEVs in an active distribution network. The approach divides operating characteristics of PHEVs into charging, discharging and null. Operation of PHEVs with change in weather conditions, intermittent characteristics of distributed generation, sector customer demand characteristics and random outages of components are modelled on Markov‐chain Monte Carlo simulation. A set of case studies are performed considering distributed operation of PHEVs as oppose to central operation of conventional units. Results suggest that distributed operation of PHEVs can potentially mitigate risk of supply insecurity of moderately stressed networks. Highly stressed networks, which are operated with PHEVs, need supplementary supports from conventional units to mitigate risk of supply insecurity.
Energy efficient transmission techniques for wireless sensor networks
Authors: Haleem Mohamed A.
Published: September 2014

Power against rate performance of a class of transmission techniques is studied in this paper. This study arises in the context of a wireless sensor network in which multiple nodes equipped with single or multiple antennas cooperatively send simultaneous and distinct signals to multiple receiving nodes, each equipped with a single receiving antenna. The criterion in deriving the techniques is to eliminate or minimise the mutual interference so as to maximise received signal‐to‐interference plus noise ratio. It is shown for low bit rates that time‐shared transmission can achieve the performance of the optimal power shared technique operating in spatially uncoupled (ideal) channels. As the bit rate increases, time‐shared transmission becomes suboptimal. In this study, best linear optimisation, dirty paper coding and zero forcing are promising techniques.
Quasilinear theory of general electromagnetic fluctuations in unmagnetized plasmas
Authors: Schlickeiser R. , Yoon P. H.
Published: September 2014

The general quasilinear Fokker-Planck kinetic equation for the plasma particle distribution functions in unmagnetized plasmas is derived, making no restrictions on the frequency of the electromagnetic fluctuations. The derived kinetic particle equation complements our earlier study of the general fluctuation's kinetic equation. For collective plasma eigenmodes and gyrotropic particle distribution functions, the two coupled kinetic equations describe the self-consistent dynamical evolution of the plasma. The limit of weakly damped collective modes correctly reproduces the well-known textbook kinetic particle equation with longitudinal Langmuir and ion-acoustic fluctuations, demonstrating, in particular, the resonant nature of parallel momentum diffusion of particles. In the limit of aperiodic modes, the Fokker-Planck equation contains the nonresonant diffusion of particles in momentum and the parallel and perpendicular momentum drag coefficients. As an application these drag and diffusion coefficients are calculated for extragalactic cosmic ray particles propagating in the unmagnetized intergalactic medium. Whereas for all cosmic rays, the perpendicular momentum diffusion in intergalactic aperiodic fluctuations is negligibly small; cosmic ray protons with energies below 105 GeV are affected by the plasma drag.
Coupled-cluster representation of Green function employing modified spectral resolutions of similarity transformed Hamiltonians
Authors: Kowalski K. , Bhaskaran-Nair K. , Shelton W. A.
Published: September 2014

In this paper we discuss a new formalism for producing an analytic coupled-cluster (CC) Green's function for an N-electron system by shifting the poles of similarity transformed Hamiltonians represented in N − 1 and N + 1 electron Hilbert spaces. Simple criteria are derived for the states in N − 1 and N + 1 electron spaces that are then corrected in the spectral resolution of the corresponding matrix representations of the similarity transformed Hamiltonian. The accurate description of excited state processes within a Green's function formalism would be of significant importance to a number of scientific communities ranging from physics and chemistry to engineering and the biological sciences. This is because the Green's function methodology provides a direct path for not only calculating properties whose underlying origins come from coupled many-body interactions but also provides a straightforward path for calculating electron transport, response, and correlation functions that allows for a direct link with experiment. As a special case of this general formulation, we discuss the application of this technique for Green's function defined by the CC with singles and doubles representation of the ground-state wave function.
Vibrationally specific photoionization cross sections of acrolein leading to the $\tilde{X}\,{}^2\!A^{\prime }$X̃A′2 ionic state
Authors: López-Domínguez Jesús A. , Lucchese Robert R. , Fulfer K. D. , Hardy David , Poliakoff E. D. , Aguilar A. A.
Published: September 2014

The vibrational branching ratios in the photoionization of acrolein for ionization leading to the \documentclass[12pt]{minimal}\begin{document}$\tilde{X}\,{}^2\!A^{\prime }$\end{document}X̃A′2 ion state were studied. Computed logarithmic derivatives of the cross section and the corresponding experimental data derived from measured vibrational branching ratios for several normal modes (ν9, ν10, ν11, and ν12) were found to be in relatively good agreement, particularly for the lower half of the 11–100 eV photon energy range considered. Two shape resonances have been found near photon energies of 15.5 and 23 eV in the photoionization cross section and have been demonstrated to originate from the partial cross section of the A′ scattering symmetry. The wave functions computed at the resonance complex energies are delocalized over the whole molecule. By looking at the dependence of the cross section on the different normal mode displacements together with the wave function at the resonant energy, a qualitative explanation is given for the change of the cross sections with respect to changing geometry.
A study on independently using static and dynamic light scattering methods to determine the coagulation rate
Authors: Zhou Hongwei , Xu Shenghua , Mi Li , Sun Zhiwei , Qin Yanming
Published: September 2014

Absolute coagulation rate constants were determined by independently, instead of simultaneously, using static and dynamic light scattering with the requested optical factors calculated by T-matrix method. The aggregating suspensions of latex particles with diameters of 500, 700, and 900 nm, that are all beyond validity limit of the traditional Rayleigh-Debye-Gans approximation, were adopted. The results from independent static and dynamic light scattering measurements were compared with those by simultaneously using static and dynamic light scattering; and three of them show good consistency. We found, theoretically and experimentally, that for independent static light scattering measurements there are blind scattering angles at that the scattering measurements become impossible and the number of blind angles increases rapidly with particle size. For independent dynamic light scattering measurements, however, there is no such a blind angle at all. A possible explanation of the observed phenomena is also presented.
Gauge theories in noncommutative homogeneous Kähler manifolds
Authors: Maeda Yoshiaki , Sako Akifumi , Suzuki Toshiya , Umetsu Hiroshi
Published: September 2014

We construct a gauge theory on a noncommutative homogeneous Kähler manifold, where we employ the deformation quantization with separation of variables for Kähler manifolds formulated by Karabegov. A key point in this construction is to obtaining vector fields which act as inner derivations for the deformation quantization. We give an explicit construction of this gauge theory on noncommutative \documentclass[12pt]{minimal}\begin{document}${\mathbb {C}}P^N$\end{document}CPN and noncommutative \documentclass[12pt]{minimal}\begin{document}${\mathbb {C}}H^N$\end{document}CHN.
Predicted roles of defects on band offsets and energetics at CIGS (Cu(In,Ga)Se2/CdS) solar cell interfaces and implications for improving performance
Authors: Xiao Hai , Goddard William A.
Published: September 2014

The laboratory performance of CIGS (Cu(In,Ga)Se2) based solar cells (20.8% efficiency) makes them promising candidate photovoltaic devices. However, there remains little understanding of how defects at the CIGS/CdS interface affect the band offsets and interfacial energies, and hence the performance of manufactured devices. To determine these relationships, we use density functional theory with the B3PW91 hybrid functional that we validate to provide very accurate descriptions of the band gaps and band offsets. This confirms the weak dependence of band offsets on surface orientation observed experimentally. We predict that the conduction band offset (CBO) of perfect CuInSe2/CdS interface is large, 0.79 eV, which would dramatically degrade performance. Moreover we show that band gap widening induced by Ga adjusts only the valence band offset, and we find that Cd impurities do not significantly affect the CBO. Thus we show that Cu vacancies at the interface play the key role in enabling the tunability of CBO. We predict that Na further improves the CBO through electrostatically elevating the valence levels to decrease the CBO, explaining the observed essential role of Na for high performance. Moreover we find that K leads to a dramatic decrease in the CBO to 0.05 eV, much better than Na. We suggest that the efficiency of CIGS devices might be improved substantially by tuning the ratio of Na to K, with the improved phase stability of Na balancing phase instability from K. All these defects reduce interfacial stability slightly, but not significantly.
Electrical detection of liquid lithium leaks from pipe joints
Authors: Schwartz J. A. , Jaworski M. A. , Mehl J. , Kaita R. , Mozulay R.
Published: September 2014

A test stand for flowing liquid lithium is under construction at Princeton Plasma Physics Laboratory. As liquid lithium reacts with atmospheric gases and water, an electrical interlock system for detecting leaks and safely shutting down the apparatus has been constructed. A defense in depth strategy is taken to minimize the risk and impact of potential leaks. Each demountable joint is diagnosed with a cylindrical copper shell electrically isolated from the loop. By monitoring the electrical resistance between the pipe and the copper shell, a leak of (conductive) liquid lithium can be detected. Any resistance of less than 2 kΩ trips a relay, shutting off power to the heaters and pump. The system has been successfully tested with liquid gallium as a surrogate liquid metal. The circuit features an extensible number of channels to allow for future expansion of the loop. To ease diagnosis of faults, the status of each channel is shown with an analog front panel LED, and monitored and logged digitally by LabVIEW.
Solving fractional Schrödinger-type spectral problems: Cauchy oscillator and Cauchy well
Authors: Żaba Mariusz , Garbaczewski Piotr
Published: September 2014

This paper is a direct offspring of the work of Garbaczewski and Stephanovich [“Lévy flights and nonlocal quantum dynamics,” J. Math. Phys. 54, 072103 (2013)] where basic tenets of the nonlocally induced random and quantum dynamics were analyzed. A number of mentions were made with respect to various inconsistencies and faulty statements omnipresent in the literature devoted to so-called fractional quantum mechanics spectral problems. Presently, we give a decisive computer-assisted proof, for an exemplary finite and ultimately infinite Cauchy well problem, that spectral solutions proposed so far were plainly wrong. As a constructive input, we provide an explicit spectral solution of the finite Cauchy well. The infinite well emerges as a limiting case in a sequence of deepening finite wells. The employed numerical methodology (algorithm based on the Strang splitting method) has been tested for an exemplary Cauchy oscillator problem, whose analytic solution is available. An impact of the inherent spatial nonlocality of motion generators upon computer-assisted outcomes (potentially defective, in view of various cutoffs), i.e., detailed eigenvalues and shapes of eigenfunctions, has been analyzed.
First-principles study of vacancy-assisted impurity diffusion in ZnO
Authors: Steiauf Daniel , Lyons John L. , Janotti Anderson , Van de Walle Chris G.
Published: September 2014

Group-III elements act as donors in ZnO when incorporated on the Zn site. Their incorporation and behavior upon annealing is governed by diffusion, which proceeds mainly through a vacancy-assisted process. We report first-principles calculations for the migration of Al, Ga, and In donors in ZnO, based on density functional theory using a hybrid functional. From the calculated migration barriers and formation energies, we determine diffusion activation energies and estimate annealing temperatures. Impurity-vacancy binding energies and migration barriers decrease from Al to In. Activation energies for vacancy-assisted diffusion are lowest for In and highest for Al.
Sub-nanosecond time-resolved ambient-pressure X-ray photoelectron spectroscopy setup for pulsed and constant wave X-ray light sources
Authors: Shavorskiy Andrey , Neppl Stefan , Slaughter Daniel S. , Cryan James P. , Siefermann Katrin R. , Weise Fabian , Lin Ming-Fu , Bacellar Camila , Ziemkiewicz Michael P. , Zegkinoglou Ioannis , Fraund Matthew W. , Khurmi Champak , Hertlein Marcus P. , Wright Travis W. , Huse Nils , Schoenlein Robert W. , Tyliszczak Tolek , Coslovich Giacomo , Robinson Joseph , Kaindl Robert A. , Rude Bruce S. , Ölsner Andreas , Mähl Sven , Bluhm Hendrik , Gessner Oliver
Published: September 2014

An apparatus for sub-nanosecond time-resolved ambient-pressure X-ray photoelectron spectroscopy studies with pulsed and constant wave X-ray light sources is presented. A differentially pumped hemispherical electron analyzer is equipped with a delay-line detector that simultaneously records the position and arrival time of every single electron at the exit aperture of the hemisphere with ∼0.1 mm spatial resolution and ∼150 ps temporal accuracy. The kinetic energies of the photoelectrons are encoded in the hit positions along the dispersive axis of the two-dimensional detector. Pump-probe time-delays are provided by the electron arrival times relative to the pump pulse timing. An average time-resolution of (780 ± 20) ps (FWHM) is demonstrated for a hemisphere pass energy Ep = 150 eV and an electron kinetic energy range KE = 503–508 eV. The time-resolution of the setup is limited by the electron time-of-flight (TOF) spread related to the electron trajectory distribution within the analyzer hemisphere and within the electrostatic lens system that images the interaction volume onto the hemisphere entrance slit. The TOF spread for electrons with KE = 430 eV varies between ∼9 ns at a pass energy of 50 eV and ∼1 ns at pass energies between 200 eV and 400 eV. The correlation between the retarding ratio and the TOF spread is evaluated by means of both analytical descriptions of the electron trajectories within the analyzer hemisphere and computer simulations of the entire trajectories including the electrostatic lens system. In agreement with previous studies, we find that the by far dominant contribution to the TOF spread is acquired within the hemisphere. However, both experiment and computer simulations show that the lens system indirectly affects the time resolution of the setup to a significant extent by inducing a strong dependence of the angular spread of electron trajectories entering the hemisphere on the retarding ratio. The scaling of the angular spread with the retarding ratio can be well approximated by applying Liouville's theorem of constant emittance to the electron trajectories inside the lens system. The performance of the setup is demonstrated by characterizing the laser fluence-dependent transient surface photovoltage response of a laser-excited Si(100) sample.
Radial convection of finite ion temperature, high amplitude plasma blobs
Authors: Wiesenberger M. , Madsen J. , Kendl A.
Published: September 2014

We present results from simulations of seeded blob convection in the scrape-off-layer of magnetically confined fusion plasmas. We consistently incorporate high fluctuation amplitude levels and finite Larmor radius (FLR) effects using a fully nonlinear global gyrofluid model. This is in line with conditions found in tokamak scrape-off-layers (SOL) regions. Varying the ion temperature, the initial blob width, and the initial amplitude, we found an FLR dominated regime where the blob behavior is significantly different from what is predicted by cold-ion models. The transition to this regime is very well described by the ratio of the ion gyroradius to the characteristic gradient scale length of the blob. We compare the global gyrofluid model with a partly linearized local model. For low ion temperatures, we find that simulations of the global model show more coherent blobs with an increased cross-field transport compared to blobs simulated with the local model. The maximal blob amplitude is significantly higher in the global simulations than in the local ones. When the ion temperature is comparable to the electron temperature, global blob simulations show a reduced blob coherence and a decreased cross-field transport in comparison with local blob simulations.
Approaching quantitative Zernike phase contrast in full-field transmission hard X-ray microscopy: Origin and reduction of artifacts
Authors: Yang Yang , Heine Ruth , Cheng Yin , Wang Chun-Chieh , Song Yen-Fang , Baumbach Tilo
Published: September 2014

Zernike phase contrast in hard X-ray transmission microscopy provides in-line observation of phase enhanced imaging of weak-absorbing objects. However, the inherent artifacts are the major hurdle to acquire quantitative structural analysis, and may even present misleading information. We explore the origin of these artifacts by frequency analysis in Fourier domain. Subsequently, a simple and flexible method for artifacts reduction well-suited for full-field transmission hard X-ray microscopy based on combination of spectra is proposed. It is demonstrated to yield quantitative local phase maps, with the characteristic artifact patterns reduced.
Shot noise of charge current in a quantum dot responded by rotating and oscillating magnetic fields
Authors: Zhao Hong-Kang , Zou Wei-Ke , Chen Qiao
Published: September 2014

We have investigated the shot noise and Fano factor of the dynamic spin-polarized quantum dot under the perturbations of a rotating magnetic field (RMF), and an oscillating magnetic field (OMF) by employing the non-equilibrium Green's function approach. The shot noise is enhanced from sub-Poissonian to super-Poissonian due to the application of RMF and OMF, and it is controlled sensitively by the tilt angle θ of RMF. The magnitude of shot noise increases as the photon energy ℏω of OMF increases, and its valley eventually is reversed to peaks as the photon energy is large enough. Double-peak structure of Fano factor is exhibited as the frequency of OMF increases to cover a large regime. The Zeeman energy μ0B0 acts as an effective gate bias to exhibit resonant behavior, and novel peak emerges associated with the applied OMF.
Communication: A novel method for generating molecular mixtures at extreme conditions: The case of hydrogen and oxygen
Authors: Pravica Michael , Sneed Daniel , White Melanie , Wang Yonggang
Published: September 2014

We have successfully created a segregated mixture of hydrogen and oxygen at high pressure in a diamond anvil cell using hard x-ray photochemistry. A keyhole (two holes connected by an opening) sample chamber was created in a metallic gasket to support two segregated powders of ammonia borane and potassium perchlorate, respectively, in each hole at a pressure of ∼5.0 GPa. Both holes were separately irradiated with synchrotron hard x-rays to release molecular oxygen and molecular hydrogen, respectively. Upon irradiation of the first KClO4-containing hole, solid reddish-orange O2 appeared in the region of irradiation and molecular oxygen was found to diffuse throughout the entire sample region. The second ammonia borane-containing hole was then irradiated and H2 was observed to form via Raman spectroscopy. Water also was observed in the ammonia borane-containing hole and possibly (in the form of ice VII) in the second hole. This unique experiment demonstrates the ability to easily create solid mixtures of simple molecular systems via x-ray irradiation and then react them via further irradiation which will aid the study of chemistry under extreme conditions.
Heterostructures based on inorganic and organic van der Waals systems
Authors: Lee Gwan-Hyoung , Lee Chul-Ho , van der Zande Arend M. , Han Minyong , Cui Xu , Arefe Ghidewon , Nuckolls Colin , Heinz Tony F. , Hone James , Kim Philip
Published: September 2014

The two-dimensional limit of layered materials has recently been realized through the use of van der Waals (vdW) heterostructures composed of weakly interacting layers. In this paper, we describe two different classes of vdW heterostructures: inorganic vdW heterostructures prepared by co-lamination and restacking; and organic-inorganic hetero-epitaxy created by physical vapor deposition of organic molecule crystals on an inorganic vdW substrate. Both types of heterostructures exhibit atomically clean vdW interfaces. Employing such vdW heterostructures, we have demonstrated various novel devices, including graphene/hexagonal boron nitride (hBN) and MoS2 heterostructures for memory devices; graphene/MoS2/WSe2/graphene vertical p-n junctions for photovoltaic devices, and organic crystals on hBN with graphene electrodes for high-performance transistors.
Josephson junction based thermometer and its application in bolometry
Authors: Faivre T. , Golubev D. , Pekola J. P.
Published: September 2014

We propose a new type of a transition edge sensor based on an Al/AlOx/Ti/AlOx/Al superconductor—insulator—superconductor—insulator—superconductor (SIS'IS) structure. It exhibits sharp dependence of zero bias resistance on temperature of the titanium absorber in the vicinity of its superconducting critical temperature. We demonstrate temperature sensitivity of the device to be 2 μK/Hz. Noise Equivalent Power (NEP) of the device, limited by the amplifier noise, is estimated to be 4×10−17 W/Hz at 313 mK. The tunnel junctions between superconducting leads should help to overcome the size limitation imposed by proximity effect in conventional transition edge sensors, without sacrificing the sensitivity. Besides that the input resistance of the device can be tuned in a wide range.
Spectral power density of the random excitation for the photoacoustic wave equation
Authors: Erkol Hakan , Unlu Mehmet Burcin
Published: September 2014

The superposition of the Green's function and its time reversal can be extracted from the photoacoustic point sources applying the representation theorems of the convolution and correlation type. It is shown that photoacoustic pressure waves at locations of random point sources can be calculated with the solution of the photoacoustic wave equation and utilization of the continuity and the discontinuity conditions of the pressure waves in the frequency domain although the pressure waves cannot be measured at these locations directly. Therefore, with the calculated pressure waves at the positions of the sources, the spectral power density can be obtained for any system consisting of two random point sources. The methodology presented here can also be generalized to any finite number of point like sources. The physical application of this study includes the utilization of the cross-correlation of photoacoustic waves to extract functional information associated with the flow dynamics inside the tissue.
Voltage controlled biaxial strain in VO2 films grown on 0.72Pb(Mg1∕3Nb2∕3)-0.28PbTiO3 crystals and its effect on the transition temperature
Authors: Petraru A. , Soni R. , Kohlstedt H.
Published: September 2014

Vanadium oxide thin films (VO2) were deposited on 0.72Pb(Mg1∕3Nb2∕3)-0.28PbTiO3 (PMN-PT) crystalline substrates using pulsed laser deposition method. Due to their huge piezoelectric coefficients in the order of 2500 pm/V, the PMN-PT substrates are used to impose additional amount of biaxial strain to the VO2 films by applying an external bias to the substrates. The influence of the biaxial strain on the transition temperature and on the conductive properties of the VO2 films is investigated in this work. Thus, a change in the biaxial strain of −0.8 × 10−3 applied in the (110) plane of the rutile cell of the VO2 lowered the metal-to-insulator transition temperature by 1.35 °C.
Improving thermostability of CrO2 thin films by doping with Sn
Authors: Ding Yi , Yuan Cheng , Wang Ziyu , Liu Shuo , Shi Jing , Xiong Rui , yin Di , Lu Zhihong
Published: September 2014

Chromium dioxide (CrO2) is an ideal material for spin electronic devices since it has almost 100% spin polarization near Fermi level. However, it is thermally unstable and easily decomposes to Cr2O3 even at room temperature. In this study, we try to improve the thermal stability of CrO2 thin films by doping with Sn whose oxide has the same structure as CrO2. High quality epitaxial CrO2 and Sn-doped CrO2 films were grown on single crystalline TiO2 (100) substrates by chemical vapor deposition. Sn4+ ions were believed to be doped into CrO2 lattice and take the lattice positions of Cr4+. The magnetic measurements show that Sn-doping leads to a decrease of magnetocrystalline anisotropy. The thermal stabilities of the films were evaluated by annealing the films at different temperatures. Sn-doped films can withstand a temperature up to 510 °C, significantly higher than what undoped films can do (lower than 435 °C), which suggests that Sn-doping indeed enhances the thermal stability of CrO2 films. Our study also indicates that Sn-doping may not change the essential half metallic properties of CrO2. Therefore, Sn-doped CrO2 is expected to be very promising for applications in spintronic devices.
Al2O3/GeOx gate stack on germanium substrate fabricated by in situ cycling ozone oxidation method
Authors: Yang Xu , Wang Sheng-Kai , Zhang Xiong , Sun Bing , Zhao Wei , Chang Hu-Dong , Zeng Zhen-Hua , Liu Honggang
Published: September 2014

Al2O3/GeOx/Ge gate stack fabricated by an in situ cycling ozone oxidation (COO) method in the atomic layer deposition (ALD) system at low temperature is systematically investigated. Excellent electrical characteristics such as minimum interface trap density as low as 1.9 × 1011 cm−2 eV−1 have been obtained by COO treatment. The impact of COO treatment against the band alignment of Al2O3 with respect to Ge is studied by x-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry (SE). Based on both XPS and SE studies, the origin of gate leakage in the ALD-Al2O3 is attributed to the sub-gap states, which may be correlated to the OH-related groups in Al2O3 network. It is demonstrated that the COO method is effective in repairing the OH-related defects in high-k dielectrics as well as forming superior high-k/Ge interface for high performance Ge MOS devices.
Electrically driven single photon emission from a CdSe/ZnSSe single quantum dot at 200 K
Authors: Quitsch Wolf , Kümmell Tilmar , Gust Arne , Kruse Carsten , Hommel Detlef , Bacher Gerd
Published: September 2014

High temperature operation of an electrically driven single photon emitter based on a single epitaxial quantum dot is reported. CdSe/ZnSSe/MgS quantum dots are embedded into a p-i-n diode architecture providing almost background free excitonic and biexcitonic electroluminescence from individual quantum dots through apertures in the top contacts. Clear antibunching with g2(τ = 0) = 0.28 ± 0.20 can be tracked up to T = 200 K, representing the highest temperature for electrically triggered single photon emission from a single quantum dot device.
Double-sided Tl2Ba2Ca2Cu3O10 thin films based high temperature superconducting filter operating above 100 K
Authors: Xie Wei , Wang Pei , He Ming , Qiao Ren , Du Jia-Nan , Gao Xiao-Xin , Liu Xin , Zhang Xu , Ji Lu , Chen Hai-Hua , Zhao Xin-Jie
Published: September 2014

A high temperature superconducting (HTS) filter on double-sided Tl2Ba2Ca2Cu3O10 (Tl-2223) thin films is designed in this letter. High-quality double-sided Tl-2223 thin films are prepared on 10 × 10 × 0.5 mm3 LaAlO3 (001) substrate. The critical temperatures Tc of the films are 120 ± 1 K and the critical current densities Jc are 3–4 MA/cm2 at 77 K for both sides. X-ray diffraction θ-2θ scans and rotational ϕ-scans prove that the films are strongly textured with the c axis perpendicular to the substrate surface. A 3-pole band-pass filter is then fabricated on the Tl-2223 thin films with 4% relative bandwidth and a center frequency of 4.0 GHz. At 77 K, 100 K, and 102 K, the insertion loss in the passband is 0.088 dB, 0.21 dB, and 0.27 dB, respectively. These performances show that the proposed HTS filter is satisfying even when the operating temperature is above 100 K, which makes it possible to work in outer space without cryogenic systems.
Objects Influence the Shape of Remembered Views: Examining Global and Local Aspects of Boundary Extension
Authors: Dickinson Christopher A , LaCombe Daniel C
Published: September 2014

Boundary extension is a constructive memory error for views of scenes in which views tend to be remembered as more spatially expansive than they appeared. In seven experiments we examined whether local differences in boundary extension within views might exist by presenting participants with overhead views of single, elongated objects or object pairs on textured ground surfaces in which objects were oriented either vertically or horizontally. Memory for views' spatial expanse was tested with either a view-recognition test or a border-adjustment test in which participants could adjust the spatial expanse of a test view using the computer's mouse. The border-adjustment test was used to assess local boundary extension (primarily); the view-recognition test was used to assess participants' memories for the overall spatial expanse of views (ie global boundary extension). Across experiments, in the border-adjustment tests specifically, participants showed more spatial expanse along the object's longer axis, in some cases restricting the view along the object's shorter axis. In addition, the recognition-test data revealed greater boundary extension for views with vertically oriented objects than for views with horizontally oriented objects. Taken together, the results suggest that objects in scene views can affect both local and global aspects of memory for spatial expanse of scene views.
The Butcher's Tongue Illusion
Authors: Michel Charles , Velasco Carlos , Salgado-Montejo Alejandro , Spence Charles
Published: September 2014

We report two experiments, based on a novel variant of the Rubber Hand Illusion (RHI), in which tactile stimulation is referred to an artificial (out-of-body) tongue. In the experiments reported here the participant's tongue was stimulated while they looked at a mirrored dummy tongue. On average, the participants agreed with the statement that they felt as if they had been touched in the location where they saw the rubber tongue being touched (experiment 1), thus demonstrating visual capture. When the external tongue was illuminated with a laser pointer (experiment 2), a significant proportion of the participants reported feeling either tactile or thermal stimulation on their own tongue. These results therefore demonstrate that the multisensory integration of visual, tactile, and proprioceptive information that gives rise to the RHI can be extended to the tongue (a body part that is rarely seen directly).
Determination of nitrogen and potassium content in greenhouse tomato leaves using a new spectro-goniophotometer
Authors: Hanping Mao , Wenjing Zhu , Hongyu Liu
Published: September 2014

We assessed the feasibility of determining the nitrogen (N) and potassium (K) content of fresh, greenhouse-grown tomato leaves by using a new polarisation reflectance spectrum spectro-goniophotometer system developed by our research group and coupled with appropriate multivariate calibration methods. The main factors that affect the polarised reflectance characteristics of tomato leaves are discussed, including incident zenith angle, azimuth, detection zenith angle, and polariser angle. Orthogonal experiments and range analyses were performed to verify the optimum angle combination from the polarised reflectance parameters. Optimum angle combination experiments were then conducted to fine-tune the optimal parameters, which resulted in the following conditions: incident zenith angle, 60°; viewing zenith angle, 45°; polariser on light source, 0°; polariser on detector, 45°; and azimuth, 180°. On this basis, 122 fresh leaves of greenhouse-grown tomato were used to establish models of N and K content. Results showed that the performance of the iPLS-GA model under incident zenith angle 60° was superior to that of the other models. The optimal model for N was achieved with R = 0.9418 and root mean square error of prediction (RMSEP) = 0.519 in the prediction set; the optimal model for K was achieved with R = 0.8645 and RMSEP = 0.700 in the prediction set. The results show that it is feasible to measure the nutrient content of fresh, greenhouse-grown tomato leaves by polarisation reflectance spectroscopy with an appropriate multivariate calibration model under angle selection. This method allows for in-depth study of plant nutrient status and rapid detection at the single-leaf scale and has theoretical and practical significance.
One severe acute respiratory syndrome coronavirus protein complex integrates processive RNA polymerase and exonuclease activities
Authors: Subissi Lorenzo , Posthuma Clara C. , Collet Axelle , Zevenhoven-Dobbe Jessika C. , Gorbalenya Alexander E. , Decroly Etienne , Snijder Eric J. , Canard Bruno , Imbert Isabelle
Published: September 2014

Significance

The 2003 severe acute respiratory syndrome (SARS) epidemic and recent emergence of Middle East respiratory syndrome highlight the potential lethality of zoonotic coronavirus infections in humans. No specific antiviral treatment options are available. Coronaviruses possess the largest known RNA virus genomes and encode a complex replication machinery consisting of 16 viral nonstructural proteins (nsps). Our study reveals that the SARS-coronavirus RNA polymerase (nsp12) needs to associate with nsp7 and nsp8 to activate its capability to replicate long RNA. Moreover, this complex associates with nsp14, the proofreading subunit required to safeguard coronavirus replication fidelity. Our study thus defines the core of an RNA-synthesizing machinery that is unique in the RNA virus world and includes several key targets for antiviral drug development.
Conformational change in the periplamic region of the flagellar stator coupled with the assembly around the rotor
Authors: Zhu Shiwei , Takao Masato , Li Na , Sakuma Mayuko , Nishino Yuuki , Homma Michio , Kojima Seiji , Imada Katsumi
Published: September 2014

Significance

Stator is the energy-converting membrane protein complex in the flagellar motor. Its ion-conducting activity is only activated when incorporated into the motor, but the mechanism for assembly-coupled activation remains a mystery. In this study, we solved the structure of a C-terminal fragment of the sodium-driven stator protein PomB (PomB
C
), the region responsible for anchoring the stator unit, at 2.0-Å resolution. In vivo disulfide cross-linking studies of PomB double-Cys mutants and their motility assay suggested that the N-terminal region of PomB
C
changes its conformation, which is expected for MotB, the counterpart of PomB in the proton-driven
Salmonella
motor, in the final step of the stator assembly around the rotor.