bluuebunny/crossref_metadata_2025 huggingface dataset:
Pyrazine-based donor tectons: synthesis, self-assembly and characterization
Authors: Bhowmick Sourav , Chakraborty Sourav , Marri Subba R. , Behera J. N. , Das Neeladri
Published: January 2016

Two donor tectons, each bearing a central pyrazine moiety covalently linked to two pyridine units, have been self-assembled with PtII2 acceptor units to yield ionic nanoscalar metallamacrocycles, having a convex hexagonal cavity.
Synthesis and evaluation of novel series of Schiff base cationic surfactants as corrosion inhibitors for carbon steel in acidic/chloride media: experimental and theoretical investigations
Authors: Abd El-Lateef Hany M. , Tantawy Ahmed H.
Published: January 2016

A new family of Schiff base cationic surfactants (CSSB) having various alkyl chain lengths were prepared and their chemical structure was elucidated by using different spectroscopic techniques (FTIR,13C-NMR and1H-NMR).
Tuning the electronic and optical properties of phosphorene by transition-metal and nonmetallic atom co-doping
Authors: Kong Long-Juan , Liu Guang-Hua , Zhang Yu-Jun
Published: January 2016

The electronic and optical properties of phosphorene co-doped with vanadium and non-metallic atoms (B, C, N and O) are investigated by employing first-principles calculations based on density functional theory.
Charge-controlled switchable methane adsorption on heteroatom-doped BNNSs
Authors: Seif Abdolvahab , Azizi Khaled
Published: January 2016

The adsorption behavior of methane (CH4) on neutral and charged states of Al-, C-, P- and Si-doped boron nitride nanosheets (BNNSs), is investigated using the density functional theory (DFT) method.
Two physical strategies to reinforce a nonmetallic photocatalyst, g-C3N4: vacuum heating and electron beam irradiation
Authors: Zhang Yunlong , Zhang Haijiao , Cheng Lingli , Wang Yujia , Miao Yu , Ding Guoji , Jiao Zheng
Published: January 2016

Herein, we demonstrated two physical strategies, namely, vacuum heating and electron beam irradiation, to reinforce a nonmetallic photocatalyst, g-C3N4.
Nisin anchored cellulose nanofibers for long term antimicrobial active food packaging
Authors: Saini Seema , Sillard Cecile , Naceur Belgacem Mohamed , Bras Julien
Published: January 2016

Increasing consumer demand for high performance bio-based materials in order to develop microbiologically safer foods has forced the food industry to revise their packaging strategies.
Two-dimensional electrospun nanofibrous membranes for promoting random skin flap survival
Authors: Sun Xiaoming , Zheng Reila , Cheng Liying , Zhao Xin , Jin Rong , Zhang Lu , Zhang Ying , Zhang Yuguang , Cui Wenguo
Published: January 2016

Electrospun fibrous membranes made of natural materials are more advantageous for random skin flap survival, and can be used as carrier implantation materials for improving skin flap survival rate.
Thermal degradation and flammability properties of multilayer structured wood fiber and polypropylene composites with fire retardants
Authors: Sun Lichao , Wu Qinglin , Xie Yanjun , Wang Fengqiang , Wang Qingwen
Published: January 2016

Single and multi-layer structured wood fiber and polypropylene composites filled with fire retardants were prepared. Fire retardant property of composites were determined by thermogravimetric analysis and cone calorimetry.
Synthesis of {110}-faceted rutile TiO2 nanocrystals from tetratitanate nanoribbons for improving dye-sensitized solar cell performance
Authors: Du Yi-en , Li Jun , Liu Yufang , Niu Xianjun , Guo Fang , Feng Qi
Published: January 2016

{110}-faceted rutile TiO2 nanocrystals with nanorods and nanoflower morphologies were synthesized through simple hydrothermal treatment of a tetratitanate nanoribbons precursor.
Covalent modification of graphene oxide by metronidazole for reinforced anti-corrosion properties of epoxy coatings
Authors: Yu Zongxue , Lv Liang , Ma Yu , Di Haihui , He Yi
Published: January 2016

This work reports a promising application of metronidazole (MET) modified graphene oxide (GO) composites (GME) for the corrosion protection of steel.
Dual redox-triggered shell-sheddable micelles self-assembled from mPEGylated starch conjugates for rapid drug release
Authors: Chen Mingjia , Gao Chunmei , Lü Shaoyu , Chen Yuanmou , Liu Mingzhu
Published: January 2016

The new diselenide-linked mPEGylated starch amphiphilic micelles was developed, which could be disrupted in the presence of 0.1% (v/v) H2O2 or 1 mM GSH.
Oxide vacancies enhanced visible active photocatalytic W19O55NMRs via strong adsorption
Authors: Qian Jingwen , Zhao Zengying , Shen Zhenguang , Zhang Guoliang , Peng Zhijian , Fu Xiuli
Published: January 2016

Oxide vacancies enhanced visible active photocatalytic W19O55nano-/micron-rods (NMRs) on methylene blue (MB) and rhodamine B (RhB)viastrong adsorption.
Synthesis of heteroatom-carbon nanosheets by solution plasma processing using N-methyl-2-pyrrolidone as precursor
Authors: Hyun Koangyong , Ueno Tomonaga , Li Oi Lun , Saito Nagahiro
Published: January 2016

Heteroatom-carbon nanosheets, composed of multi-layer graphene with turbostratic stacking, were successfully synthesized through a solution plasma processing (SPP) with N-methyl-2-pyrrolidone at room temperature and an atmospheric pressure.
Pseudo-first order reaction kinetics and thermodynamic properties study of neem oil esterification using MgO grafted natural hydroxyapatite
Authors: Sahu Himadri , Mohanty Kaustubha
Published: January 2016

In this work, waste fish bone was used as a source of natural hydroxyapatite which was later used for the preparation of a metal grafted catalyst.
Asymmetric synthesis of functionalized pyrrolizidines by an organocatalytic and pot-economy strategy
Authors: Lin Chia-Hsin , Hong Bor-Cherng , Lee Gene-Hsiang
Published: January 2016

An enantioselective synthesis of indolizidines was achieved with a one-step purification by sequential asymmetric Michael–oxidative esterification–Michael–reduction–reductive Mannich–amidation reactions.
Determination of concentration-dependent diffusion coefficient of seven solvents in polystyrene systems using FTIR-ATR technique: experimental and mathematical studies
Authors: Karimi Mohammad , Tashvigh Akbar Asadi , Asadi Fateme , Ashtiani Farzin Zokaee
Published: January 2016

In the present study a new mathematical model's outcome based on experimental data is considered to determine the diffusion coefficients in polystyrene/solvent systems as a function of solvent concentration.
DNA templated self-assembly of gold nanoparticle clusters in the colorimetric detection of plant viral DNA using a gold nanoparticle conjugated bifunctional oligonucleotide probe
Authors: Dharanivasan G. , Mohammed Riyaz S. U. , Michael Immanuel Jesse D. , Raja Muthuramalingam T. , Rajendran G. , Kathiravan K.
Published: January 2016

The DNA templated self-assembly of gold nanoparticles clustered in different configurations (nn = 2–∞) was investigated in the colorimetric detection of ToLCNDV DNA using a gold nanoparticle conjugated bifunctional oligonucleotide probe.
Iron(iii) and cobalt(iii) complexes with both tautomeric (keto and enol) forms of aroylhydrazone ligands: catalysts for the microwave assisted oxidation of alcohols
Authors: Sutradhar Manas , Alegria Elisabete C. B. A. , Mahmudov Kamran T. , Guedes da Silva M. Fátima C. , Pombeiro Armando J. L.
Published: January 2016

Aroylhydrazone Fe(iii) and Co(iii) complexes of bothketoandenoltautomeric forms of the ligand are reported and shown to catalyze the microwave-assisted solvent-free peroxidative oxidation (by TBHP) of primary and secondary alcohols.
Growth and characterization of zeolitic imidazolate framework-8 nanocrystalline layers on microstructured surfaces for liquid crystal alignment
Authors: Chen Lu-Jian , Luo Bin , Li Wen-Song , Yang Can , Ye Tao , Li Sen-Sen , Wang Xiao-Zhong , Cui Yuan-Jing , Li Han-Ying , Qian Guo-Dong
Published: January 2016

The coverage of zeolitic imidazolate framework-8 (ZIF-8) nanocrystals deposited on patterned sol–gel films is significantly affected by the surface morphology. The ZIF-8 layer can induce vertical alignment of a typical nematic liquid crystal (LC) E7.
Anomalous mechanical strengths and shear deformation paths of Al2O3polymorphs with high ionicity
Authors: Zhang Z. , Fu Z. H. , Zhang R. F. , Legut D. , Guo H. B.
Published: January 2016

Alumina (Al2O3) formed by selective oxidization provides an effective way to protect aluminide alloys against corrosion for sustainable applications.
One-pot four component domino strategy for the synthesis of novel spirooxindole pyrrolizine linked 1,2,3-triazoles via stereo- and regioselective [3 + 2] cycloaddition reaction in acidic medium
Authors: M. Rajeswari , Kumari Sudesh , Khurana Jitender M.
Published: January 2016

An efficient, one-pot four component condensation has been reported for the synthesis of spirooxindole pyrrolizine linked 1,2,3-triazolesvia[3 + 2] cycloaddition. The structures were confirmed by1H NMR,13C NMR, mass spectra and X-ray.
Simple synthesis of a CoMoS4based nanostructure and its application for high-performance supercapacitors
Authors: Dai Yan-Hua , Kong Ling-Bin , Yan Kun , Shi Ming , Zhang Tong , Luo Yong-Chun , Kang Long
Published: January 2016

Synthesis procedure for CoMoS4nanoparticles.
Fluorescence “on–off–on” chemosensor for selective detection of Hg2+ and S2−: application to bioimaging in living cells
Authors: Vengaian K. Muthu , Britto C. Denzil , Sekar Karuppannan , Sivaraman Gandhi , Singaravadivel Subramanian
Published: January 2016

A phenothiazine based diamino-malenonitrile-linked (P-1) chromogenic and fluorogenic probe was synthesized and characterized for the specific detection of Hg2+ and S2−. The probe P-1 can be used for selective imaging of Hg2+ and S2− in living cells.
Photoresponsive amphiphilic azobenzene–PEG self-assembles to form supramolecular nanostructures for drug delivery applications
Authors: Yadav Santosh , Deka Smriti Rekha , Verma Geeta , Sharma Ashwani Kumar , Kumar Pradeep
Published: January 2016

Self-assembled smart nanostructures have emerged as controlled and site-specific systems for drug delivery applications.
Synthesis and biological evaluation of novel carbazolyl glyoxamides as anticancer and antibacterial agents
Authors: Reddy P O Venkataramana , Tantak Mukund P. , Valdez Reyna , Singh Rajnish Prakash , Singh Okram Mukherjee , Sadana Rachna , Kumar Dalip
Published: January 2016

A new library of 24 carbazolyl glyoxamides14a–xwere designed and synthesized from glyoxalic acids and arylamines in the presence of HATU as a coupling reagent under MW irradiation.
Dual tuning of 1 D heteroatoms doped porous carbon nanoarchitectures for supercapacitors: the role of balanced P/N doping and core@shell nano-networks
Authors: Li Yuanyuan , Chen Zhimin , Zhang Jianan , Xu Qun
Published: January 2016

Intriguing P and N co-doped porous CNT@carbon core@shell nano-networks (PN-CNTs) were facilely synthesized and demonstrated to be ideal carbon nanostructures for electrochemical performance optimization on supercapacitors.
One-pot synthesis of La-doped SnO2 layered nanoarrays with an enhanced gas-sensing performance toward acetone
Authors: Gao Fan , Qin Guohui , Li Yuehua , Jiang Qiuping , Luo Li , Zhao Kang , Liu Yongjun , Zhao Heyun
Published: January 2016

Acetone-sensing properties were greatly enhanced by La-doped SnO2 nanoarray with a novel nanostructure of double nanorod layers synthesized by hydrothermal method.
Enhanced aging properties of HKUST-1 in hydrophobic mixed-matrix membranes for ammonia adsorption
Authors: DeCoste Jared B. , Denny, Jr. Michael S. , Peterson Gregory W. , Mahle John J. , Cohen Seth M.
Published: January 2016

The metal-organic framework (MOF) HKUST-1 incorporated into a mixed-matrix membrane (MMM) exhibits enhanced water stability while maintaining gas removal capabilities commensurate with those of the free powder form.
Phosphorus chemistry: discoveries and advances
Authors: Waterman Rory
Published: January 2016

Welcome to this themed issue of Dalton Transactions entitled “Phosphorus Chemistry: Discoveries and Advances”.
Generalised two‐box cascaded Hammerstein‐like digital predistorter for wide‐band RF power amplifiers
Authors: Xu Gaoming , Liu Taijun , Ye Yan , Li Jun , Ghannouchi Fadhel M.
Published: January 2016

A generalised two‐box cascaded Hammerstein‐like (GTBC‐H) digital predistorter is proposed for linearising wide‐band RF power amplifiers (PAs). The GTBC‐H predistorter is composed of a static nonlinearity block for countervailing the strong static nonlinearities and a dynamic nonlinearity block for compensating the memory effects of RF PAs. The proposed predistorter adds extended cross‐terms of the leading terms and some lagging envelope terms in the dynamic nonlinearity block to compensate the memory effects of wide‐band RF PAs more effectively. A 460 MHz and a 1.94 GHz Doherty RF PA are utilised to validate the performance of the proposed predistorter when a three‐carrier wide‐band CDMA and a single‐carrier long‐term evaluation signal are applied separately. The validation results illustrate that the proposed GTBC‐H predistorter can further suppress the residual out‐of‐band emission over the augmented Hammerstein, the enhanced Hammerstein and the parallel‐LUT‐MP‐EMP predistorter.
Compact MIMO/diversity slot antenna for UWB applications with band‐notched characteristic
Authors: Chandel R. , Gautam A.K.
Published: January 2016

A novel MIMO sharp band‐notched antenna with high isolation for UWB applications is presented. The antenna consists of two antenna elements with an overall area of 18 × 36 mm2. A T‐shaped stub is extruded in the ground plane to improve isolation and an L‐shaped stub to introduce band‐notched function C‐band (3.62–4.77 GHz). The designed antenna possesses a low mutual coupling of <−20 dB over the operating band from 2.9 to 20 GHz. The performance of this antenna is studied in terms of isolation between the two ports, radiation pattern, efficiency, realised gain, and envelope correlation coefficient.
Surgery for Left Ventricular Outflow Tract Obstruction with a Relatively Thin Interventricular Septum
Authors: Sugiki Hiroshi , Ooka Tomonori , Kato Hiroki , Wakasa Satoru , Tachibana Tsuyoshi , Matsui Yoshiro , Shingu Yasushige
Published: January 2016

Background To examine the results of myectomy and mitral valve surgery for systolic anterior motion (SAM) of the mitral valve and left ventricular outflow tract obstruction (LVOTO) with a relatively thin interventricular septum.

Methods The subjects were 12 patients with SAM and LVOTO. Eight had hypertrophic obstructive cardiomyopathy (HOCM) with a mean interventricular septal thickness of 16 mm. Three had sigmoid septum and one had an unknown etiology. For HOCM, isolated extended myectomy was performed when mitral regurgitation was mild (n = 1) and extended myectomy plus mitral valve surgery was performed when mitral regurgitation was more than mild (n = 4) or primary valve etiologies existed (n = 3). Myectomy was performed for the three cases with sigmoid septum. Myectomy plus height reduction of the posterior mitral leaflet was performed for the one case with the unknown etiology of SAM.

Results In the patients with HOCM, the maximum LVOT pressure gradient significantly decreased from 140 ± 18 to 16 ± 6 and 3 ± 3 mm Hg, while mitral regurgitation significantly decreased from 2.3 ± 0.5 to 0.5 ± 0.3 and 0.4 ± 0.2 at pre-op, early post-op, and last follow-up (3 ± 1 years), respectively. In the other etiologies, the maximum LVOT pressure gradient changed from 56 ± 15 to 25 ± 15 and 5 ± 4 mm Hg; mitral regurgitation changed from 2.0 ± 0.6 to 1.3 ± 0.3 and 1.3 ± 0.8, at pre-op, early post-op, and the last follow-up (3 ± 2 years), respectively.

Conclusion Myectomy with mitral valve surgery is an option for SAM and LVOTO in patients with a relatively thin interventricular septum.
New parallelizable schemes for integrating the Dissipative Particle Dynamics with Energy conservation
Authors: Homman Ahmed-Amine , Maillet Jean-Bernard , Roussel Julien , Stoltz Gabriel
Published: January 2016

This work presents new parallelizable numerical schemes for the integration of dissipative particle dynamics with energy conservation. So far, no numerical scheme introduced in the literature is able to correctly preserve the energy over long times and give rise to small errors on average properties for moderately small time steps, while being straightforwardly parallelizable. We present in this article two new methods, both straightforwardly parallelizable, allowing to correctly preserve the total energy of the system. We illustrate the accuracy and performance of these new schemes both on equilibrium and nonequilibrium parallel simulations.
Magnetically insulated coaxial vacuum diode with partial space-charge-limited explosive emission from edge-type cathode
Authors: Belomyttsev S. Ya. , Rostov V. V. , Romanchenko I. V. , Shunailov S. A. , Kolomiets M. D. , Mesyats G. A. , Sharypov K. A. , Shpak V. G. , Ulmaskulov M. R. , Yalandin M. I.
Published: January 2016

The vacuum current associated with any type of electron emission for arbitrary configuration of the diode depends on the combination of the applied electric field and vacuum space charge (VSC) field created by the current. Such fundamental statement should give very close links between the diode current and the normalized cathode field θ which has been introduced by Forbes in 2008 for planar diodes as a reduction in the cathode surface field: θ = field-with/field-without VSC. This article reports the universal approximation of the type of cos(πθ/2) that is the ratio of the actual current and the fully space-charge-limited current. Also, the theoretical treatment and the experimental method of determination of the dynamic emissive characteristics of the macroscopic explosive emission from edge-type cathodes in the coaxial diode are developed. The experimental results obtained with a picosecond time reference between the cathode voltage and the onset of the high-current electron beam exhibit a good coincidence with the theoretical predictions. The presented methods enable the analysis of a real-time-resolved dynamics associated with the dense, magnetized electron beam formation, acceleration and drift motion, including kinematic effects and the phase-stable excitation of high-power microwave oscillators.
Global triplet potential energy surfaces for the N2(X1Σ) + O(3P) → NO(X2Π) + N(4S) reaction
Authors: Lin Wei , Varga Zoltan , Song Guoliang , Paukku Yuliya , Truhlar Donald G.
Published: January 2016

This work presents two global triplet potential energy surfaces (PESs) for the high-energy reaction N2(X1Σ) + O(3P) → NO(X2Π) + N(4S)—in particular, for the lowest energy 3A′ and 3A″ PESs. In order to obtain the energies needed for fitting analytic surfaces, we carried out multireference configuration interaction (MRCI) calculations based on wave functions obtained from state-averaged complete active space self-consistent field calculations for 2280 geometries for the three lowest 3A″ states and for 2298 geometries for the three lowest 3A′ states. The lowest-energy 3A′ and 3A″ states at each of these geometries were then improved by applying the dynamically scaled external correlation (DSEC) method to all MRCI points, and the resulting DSEC energies were used for construction of the ground-state PES for each symmetry. The many-body component of the DSEC energies for the three-dimensional 3A′ and 3A″ PESs was then least-squares fitted in terms of permutationally invariant polynomials in mixed exponential–Gaussian bond order variables. The global and local minima as well as the transition structures of both the 3A′ and the 3A″ analytic PES were explored. In agreement with previous work, we find that the reverse reaction is barrierless on the 3A″ surface along the minimum energy pathway. However, we have explored several new local minima and transition structures on the 3A′ PES. Furthermore, based on the newly found minima and transition structures, two independent reaction mechanisms have been illustrated for the reaction path on the 3A′ PES. The analytic surfaces may be used for dynamics calculations of electronically adiabatic reactive scattering and energy transfer.
Site-resolved multiple-quantum filtered correlations and distance measurements by magic-angle spinning NMR: Theory and applications to spins with weak to vanishing quadrupolar couplings
Authors: Eliav U. , Haimovich A. , Goldbourt A.
Published: January 2016

We discuss and analyze four magic-angle spinning solid-state NMR methods that can be used to measure internuclear distances and to obtain correlation spectra between a spin I = 1/2 and a half-integer spin S > 1/2 having a small quadrupolar coupling constant. Three of the methods are based on the heteronuclear multiple-quantum and single-quantum correlation experiments, that is, high rank tensors that involve the half spin and the quadrupolar spin are generated. Here, both zero and single-quantum coherence of the half spins are allowed and various coherence orders of the quadrupolar spin are generated, and filtered, via active recoupling of the dipolar interaction. As a result of generating coherence orders larger than one, the spectral resolution for the quadrupolar nucleus increases linearly with the coherence order. Since the formation of high rank tensors is independent of the existence of a finite quadrupolar interaction, these experiments are also suitable to materials in which there is high symmetry around the quadrupolar spin. A fourth experiment is based on the initial quadrupolar-driven excitation of symmetric high order coherences (up to p = 2S, where S is the spin number) and subsequently generating by the heteronuclear dipolar interaction higher rank (l + 1 or higher) tensors that involve also the half spins. Due to the nature of this technique, it also provides information on the relative orientations of the quadrupolar and dipolar interaction tensors. For the ideal case in which the pulses are sufficiently strong with respect to other interactions, we derive analytical expressions for all experiments as well as for the transferred echo double resonance experiment involving a quadrupolar spin. We show by comparison of the fitting of simulations and the analytical expressions to experimental data that the analytical expressions are sufficiently accurate to provide experimental 7Li–13C distances in a complex of lithium, glycine, and water. Discussion of the regime for which such an approach is valid is given.
Potential energy surface of triplet N2O2
Authors: Varga Zoltan , Meana-Pañeda Rubén , Song Guoliang , Paukku Yuliya , Truhlar Donald G.
Published: January 2016

We present a global ground-state triplet potential energy surface for the N2O2 system that is suitable for treating high-energy vibrational-rotational energy transfer and collision-induced dissociation. The surface is based on multi-state complete-active-space second-order perturbation theory/minimally augmented correlation-consistent polarized valence triple-zeta electronic structure calculations plus dynamically scaled external correlation. In the multireference calculations, the active space has 14 electrons in 12 orbitals. The calculations cover nine arrangements corresponding to dissociative diatom-diatom collisions of N2, O2, and nitric oxide (NO), the interaction of a triatomic molecule (N2O and NO2) with the fourth atom, and the interaction of a diatomic molecule with a single atom (i.e., the triatomic subsystems). The global ground-state potential energy surface was obtained by fitting the many-body interaction to 54 889 electronic structure data points with a fitting function that is a permutationally invariant polynomial in terms of bond-order functions of the six interatomic distances.
A two-layer approach to the coupled coherent states method
Authors: Green James A. , Grigolo Adriano , Ronto Miklos , Shalashilin Dmitrii V.
Published: January 2016

In this paper, a two-layer scheme is outlined for the coupled coherent states (CCS) method, dubbed two-layer CCS (2L-CCS). The theoretical framework is motivated by that of the multiconfigurational Ehrenfest method, where different dynamical descriptions are used for different subsystems of a quantum mechanical system. This leads to a flexible representation of the wavefunction, making the method particularly suited to the study of composite systems. It was tested on a 20-dimensional asymmetric system-bath tunnelling problem, with results compared to a benchmark calculation, as well as existing CCS, matching-pursuit/split-operator Fourier transform, and configuration interaction expansion methods. The two-layer method was found to lead to improved short and long term propagation over standard CCS, alongside improved numerical efficiency and parallel scalability. These promising results provide impetus for future development of the method for on-the-fly direct dynamics calculations.
Subcritical excitation of the current-driven Tayler instability by super-rotation
Authors: Rüdiger G. , Schultz M. , Gellert M. , Stefani F.
Published: January 2016

It is known that in a hydrodynamic Taylor-Couette system, uniform rotation or a rotation law with positive shear (“super-rotation”) is linearly stable. It is also known that a conducting fluid under the presence of a sufficiently strong axial electric-current becomes unstable against nonaxisymmetric disturbances. It is thus suggestive that a cylindrical pinch formed by a homogeneous axial electric-current is stabilized by rotation laws with dΩ/dR ≥ 0. For magnetic Prandtl number Pm ≠ 1 and for slow rotation, however, rigid rotation and super-rotation support the instability by lowering the critical Hartmann numbers. This double-diffusive instability of super-rotation even exists for toroidal magnetic fields with rather arbitrary radial profiles, the current-free profile Bϕ ∝ 1/R included. The sign of the azimuthal drift of the nonaxisymmetric hydromagnetic instability pattern strongly depends on the magnetic Prandtl number. The pattern counterrotates with the flow for Pm ≪ 1 and it corotates for Pm ≫ 1 while for rotation laws with negative shear, the instability pattern migrates in the direction of the basic rotation for all Pm. An axial electric-current of minimal 3.6 kA flowing inside or outside the inner cylinder suffices to realize the double-diffusive instability for super-rotation in experiments using liquid sodium as the conducting fluid between the rotating cylinders. The limit is 11 kA if a gallium alloy is used.
Correlation of film morphology and defect content with the charge-carrier transport in thin-film transistors based on ZnO nanoparticles
Authors: Polster S. , Jank M. P. M. , Frey L.
Published: January 2016

The correlation of defect content and film morphology with the charge-carrier transport in field-effect devices based on zinc oxide nanoparticles was investigated. Changes in the defect content and the morphology were realized by annealing and sintering of the nanoparticle thin films. Temperature-dependent electrical measurements reveal that the carrier transport is thermally activated for both the unsintered and sintered thin films. Reduced energetic barrier heights between the particles have been determined after sintering. Additionally, the energetic barrier heights between the particles can be reduced by increasing the drain-to-source voltage and the gate-to-source voltage. The changes in the barrier height are discussed with respect to information obtained by scanning electron microscopy and photoluminescence measurements. It is found that a reduction of surface states and a lower roughness at the interface between the particle layer and the gate dielectric lead to lower barrier heights. Both surface termination and layer morphology at the interface affect the barrier height and thus are the main criteria for mobility improvement and device optimization.
Ridge InGaAs/InP multi-quantum-well selective growth in nanoscale trenches on Si (001) substrate
Authors: Li S. , Zhou X. , Li M. , Kong X. , Mi J. , Wang M. , Wang W. , Pan J.
Published: January 2016

Metal organic chemical vapor deposition of InGaAs/InP multi-quantum-well in nanoscale V-grooved trenches on Si (001) substrate was studied using the aspect ratio trapping method. A high quality GaAs/InP buffer layer with two convex {111} B facets was selectively grown to promote the highly uniform, single-crystal ridge InP/InGaAs multi-quantum-well structure growth. Material quality was confirmed by transmission electron microscopy and room temperature micro-photoluminescence measurements. This approach shows great promise for the fabrication of photonics devices and nanolasers on Si substrate.
Quantitative contrast-enhanced optical coherence tomography
Authors: Winetraub Yonatan , SoRelle Elliott D. , Liba Orly , de la Zerda Adam
Published: January 2016

We have developed a model to accurately quantify the signals produced by exogenous scattering agents used for contrast-enhanced Optical Coherence Tomography (OCT). This model predicts distinct concentration-dependent signal trends that arise from the underlying physics of OCT detection. Accordingly, we show that real scattering particles can be described as simplified ideal scatterers with modified scattering intensity and concentration. The relation between OCT signal and particle concentration is approximately linear at concentrations lower than 0.8 particle per imaging voxel. However, at higher concentrations, interference effects cause signal to increase with a square root dependence on the number of particles within a voxel. Finally, high particle concentrations cause enough light attenuation to saturate the detected signal. Predictions were validated by comparison with measured OCT signals from gold nanorods (GNRs) prepared in water at concentrations ranging over five orders of magnitude (50 fM to 5 nM). In addition, we validated that our model accurately predicts the signal responses of GNRs in highly heterogeneous scattering environments including whole blood and living animals. By enabling particle quantification, this work provides a valuable tool for current and future contrast-enhanced in vivo OCT studies. More generally, the model described herein may inform the interpretation of detected signals in modalities that rely on coherence-based detection or are susceptible to interference effects.
Growth of metalloid aluminum clusters on graphene vacancies
Authors: Alnemrat Sufian , Mayo Dennis H. , DeCarlo Samantha , Hooper Joseph P.
Published: January 2016

Ab initio simulations are used to show that graphene vacancy sites may offer a means of templated growth of metalloid aluminum clusters from their monohalide precursors. We present density functional theory and ab initio molecular dynamics simulations of the aluminum halide AlCl interacting with a graphene surface. Unlike a bare Al adatom, AlCl physisorbs weakly on vacancy-free graphene with little charge transfer and no hybridization with carbon orbitals. The barrier for diffusion of AlCl along the surface is negligible. Covalent bonding is seen only with vacancies and results in strong chemisorption and considerable distortion of the nearby lattice. Car-Parrinello molecular dynamics simulations of AlCl liquid around a graphene single vacancy show spontaneous metalloid cluster growth via a process of repeated insertion reactions. This suggests a means of templated cluster nucleation and growth on a carbon substrate and provides some confirmation for the role of a trivalent aluminum species in nucleating a ligated metalloid cluster from AlCl and AlBr solutions.
Thermal generation of spin current in epitaxial CoFe2O4 thin films
Authors: Guo Er-Jia , Herklotz Andreas , Kehlberger Andreas , Cramer Joel , Jakob Gerhard , Kläui Mathias
Published: January 2016

The longitudinal spin Seebeck effect (LSSE) has been investigated in high-quality epitaxial CoFe2O4 (CFO) thin films. The thermally excited spin currents in the CFO films are electrically detected in adjacent Pt layers due to the inverse spin Hall effect. The LSSE signal exhibits a linear increase with increasing temperature gradient, yielding a LSSE coefficient of ∼100 nV/K at room temperature. The temperature dependence of the LSSE is investigated from room temperature down to 30 K, showing a significant reduction at low temperatures, revealing that the total amount of thermally generated magnons decreases. Furthermore, we demonstrate that the spin Seebeck effect is an effective tool to study the magnetic anisotropy induced by epitaxial strain, especially in ultrathin films with low magnetic moments.
Uncertainty analysis of thermoreflectance measurements
Authors: Yang Jia , Ziade Elbara , Schmidt Aaron J.
Published: January 2016

We derive a generally applicable formula to calculate the precision of multi-parameter measurements that apply least squares algorithms. This formula, which accounts for experimental noise and uncertainty in the controlled model parameters, is then used to analyze the uncertainty of thermal property measurements with pump-probe thermoreflectance techniques. We compare the uncertainty of time domain thermoreflectance and frequency domain thermoreflectance (FDTR) when measuring bulk materials and thin films, considering simultaneous measurements of various combinations of thermal properties, including thermal conductivity, heat capacity, and thermal boundary conductance. We validate the uncertainty analysis using Monte Carlo simulations on data from FDTR measurements of an 80 nm gold film on fused silica.
Thin yttrium iron garnet films grown by pulsed laser deposition: Crystal structure, static, and dynamic magnetic properties
Authors: Sokolov N. S. , Fedorov V. V. , Korovin A. M. , Suturin S. M. , Baranov D. A. , Gastev S. V. , Krichevtsov B. B. , Maksimova K. Yu. , Grunin A. I. , Bursian V. E. , Lutsev L. V. , Tabuchi M.
Published: January 2016

Pulsed laser deposition has been used to grow thin (10–84 nm) epitaxial layers of Yttrium Iron Garnet Y3Fe5O12 (YIG) on (111)–oriented Gadolinium Gallium Garnet substrates at different growth conditions. Atomic force microscopy showed flat surface morphology both on micrometer and nanometer scales. X-ray diffraction measurements revealed that the films are coherent with the substrate in the interface plane. The interplane distance in the [111] direction was found to be by 1.2% larger than expected for YIG stoichiometric pseudomorphic film indicating presence of rhombohedral distortion in this direction. Polar Kerr effect and ferromagnetic resonance measurements showed existence of additional magnetic anisotropy, which adds to the demagnetizing field to keep magnetization vector in the film plane. The origin of the magnetic anisotropy is related to the strain in YIG films observed by XRD. Magneto-optical Kerr effect measurements revealed important role of magnetization rotation during magnetization reversal. An unusual fine structure of microwave magnetic resonance spectra has been observed in the film grown at reduced (0.5 mTorr) oxygen pressure. Surface spin wave propagation has been demonstrated in the in-plane magnetized films.
Non-Markovian dynamics of single- and two-qubit systems interacting with Gaussian and non-Gaussian fluctuating transverse environments
Authors: Rossi Matteo A. C. , Paris Matteo G. A.
Published: January 2016

We address the interaction of single- and two-qubit systems with an external transverse fluctuating field and analyze in detail the dynamical decoherence induced by Gaussian noise and random telegraph noise (RTN). Upon exploiting the exact RTN solution of the time-dependent von Neumann equation, we analyze in detail the behavior of quantum correlations and prove the non-Markovianity of the dynamical map in the full parameter range, i.e., for either fast or slow noise. The dynamics induced by Gaussian noise is studied numerically and compared to the RTN solution, showing the existence of (state dependent) regions of the parameter space where the two noises lead to very similar dynamics. We show that the effects of RTN noise and of Gaussian noise are different, i.e., the spectrum alone is not enough to summarize the noise effects, but the dynamics under the effect of one kind of noise may be simulated with high fidelity by the other one.
Band structure effects on resonant tunneling in III-V quantum wells versus two-dimensional vertical heterostructures
Authors: Campbell Philip M. , Tarasov Alexey , Joiner Corey A. , Ready W. Jud , Vogel Eric M.
Published: January 2016

Since the invention of the Esaki diode, resonant tunneling devices have been of interest for applications including multi-valued logic and communication systems. These devices are characterized by the presence of negative differential resistance in the current-voltage characteristic, resulting from lateral momentum conservation during the tunneling process. While a large amount of research has focused on III-V material systems, such as the GaAs/AlGaAs system, for resonant tunneling devices, poor device performance and device-to-device variability have limited widespread adoption. Recently, the symmetric field-effect transistor (symFET) was proposed as a resonant tunneling device incorporating symmetric 2-D materials, such as transition metal dichalcogenides (TMDs), separated by an interlayer barrier, such as hexagonal boron-nitride. The achievable peak-to-valley ratio for TMD symFETs has been predicted to be higher than has been observed for III-V resonant tunneling devices. This work examines the effect that band structure differences between III-V devices and TMDs has on device performance. It is shown that tunneling between the quantized subbands in III-V devices increases the valley current and decreases device performance, while the interlayer barrier height has a negligible impact on performance for barrier heights greater than approximately 0.5 eV.
A cryogenically cooled, ultra-high-energy-resolution, trap-based positron beam
Authors: Natisin M. R. , Danielson J. R. , Surko C. M.
Published: January 2016

A technique is described to produce a pulsed, magnetically guided positron beam with significantly improved beam characteristics over those available previously. A pulsed, room-temperature positron beam from a buffer gas trap is used as input to a trap that captures the positrons, compresses them both radially and axially, and cools them to 50 K on a cryogenic CO buffer gas before ejecting them as a pulsed beam. The total energy spread of the beam formed using this technique is 6.9 ± 0.7 meV FWHM, which is a factor of ∼5 better than the previous state-of-the-art, while simultaneously having sub-microsecond temporal resolution and millimeter spatial resolution. Possible further improvements in beam quality are discussed.
A tension-torsional fatigue testing apparatus for micro-scale components
Authors: Fu Sichao , Wang Lei , Chen Gang , Yu Dunji , Chen Xu
Published: January 2016

Mechanical characterization of micro-scale components under complex loading conditions is a great challenge. To meet such a challenge, a microtension-torsional fatigue testing apparatus is developed in this study that specializes in the evaluation of multiaxial fatigue behavior of thin stent wires. The actuation and measurement in two controlled directions are incorporated in the tensile and torsional load frames, respectively, and a thrust air bearing is applied for the coupling of the two frames. The axial deformation of specimens measured by a grating sensor built in the linear motor and by a non-contact displacement detect system is compared and corrected. The accuracy of the torque measurement is proved by torsion tests on thin wires of 316L stainless steel in nominal diameters of 100 μm. Multistep torsion test, multiaxial ratcheting test, and a fully strain controlled multiaxial cyclic test are performed on 100 μm and 200 μm-diameter 316L wires using this apparatus. The capability of the equipment in tension-torsional cyclic tests for micro-scale specimens is demonstrated by the experimental results.
Oriented shift and inverse of the daughter droplet due to the asymmetry of grand-daughter droplets of multiple emulsions in a symmetric flow field
Authors: Wang Jingtao , Wang Xiaoyong , Tai Mo , Guan Jing
Published: January 2016

The rheological behaviors of multiple emulsions with an asymmetric internal structure in its third layer (grand-daughter droplets) under a modest extensional flow are investigated in this paper. The asymmetric structure will lead to the asymmetric circulation and pressure distribution inside the globule and eventually result in the oriented shift of its daughter droplet (in the second layer). The shift direction is affected not only by the structural asymmetry parameter As but also by some flow features including the capillary number Ca and viscosity ratio λ. Changes of these factors might cause the reverse of the shift direction, which are shown in three phase diagrams as a function of As, Ca, and λ. As the oriented shift of the daughter droplet would cause the oriented breakup of the multiple-emulsion globule, this phenomenon could be applied for the controlled release of the globule insertion by a hydrodynamic approach.
Microscopic potential fluctuations in Si-doped AlGaN epitaxial layers with various AlN molar fractions and Si concentrations
Authors: Kurai Satoshi , Miyake Hideto , Hiramatsu Kazumasa , Yamada Yoichi
Published: January 2016

Nanoscopic potential fluctuations of Si-doped AlGaN epitaxial layers with the AlN molar fraction varying from 0.42 to 0.95 and Si-doped Al0.61Ga0.39N epitaxial layers with Si concentrations of 3.0–37 × 1017 cm−3 were investigated by cathodoluminescence (CL) imaging combined with scanning electron microscopy. The spot CL linewidths of AlGaN epitaxial layers broadened as the AlN molar fraction was increased to 0.7, and then narrowed at higher AlN molar fractions. The experimental linewidths were compared with the theoretical prediction from the alloy broadening model. The trends displayed by our spot CL linewidths were consistent with calculated results at AlN molar fractions of less than about 0.60, but the spot CL linewidths were markedly broader than the calculated linewidths at higher AlN molar fractions. The dependence of the difference between the spot CL linewidth and calculated line broadening on AlN molar fraction was found to be similar to the dependence of reported S values, indicating that the vacancy clusters acted as the origin of additional line broadening at high AlN molar fractions. The spot CL linewidths of Al0.61Ga0.39N epitaxial layers with the same Al concentration and different Si concentrations were nearly constant in the entire Si concentration range tested. From the comparison of reported S values, the increase of VAl did not contribute to the linewidth broadening, unlike the case of the VAl clusters.
Tailoring the highest occupied molecular orbital level of poly(N-vinylcarbazole) hole transport layers in organic multilayer heterojunctions
Authors: Park Young Ran , Kim Hyeong Jin , Im Sungjin , Seo Sunae , Shin Koo , Choi Won Kook , Hong Young Joon
Published: January 2016

We report the tailoring of the electronic structure of poly(N-vinylcarbazole) (PVK) using a mixture layer of polyaniline:poly(p-styrenesulfonic acid) (PANI:PSS) in organic multilayer PVK/PANI:PSS/poly(3,4-ethylenedioxythiophene):PSS heterojunctions. The overall electronic structure of the PVK overlayer was systematically down-shifted while the work function of PANI:PSS increased as a function of the PSS-to-PANI weight ratio for the ratio range from 1 to 11 in the PANI:PSS film. The down-shift in the highest occupied molecular orbital of PVK markedly reduced the hole injection barrier from PVK to quantum-dot (QD) layers in QD-light emitting diode (QD-LED) structures, resulting in superior electrical and electroluminescent characteristics for QD-LEDs. The influences of PANI:PSS thickness on the electronic structure of PVK and the performance of QD-LEDs are also discussed.
Observation of fundamental thermal noise in optical fibers down to infrasonic frequencies
Authors: Dong Jing , Huang Junchao , Li Tang , Liu Liang
Published: January 2016

The intrinsic thermal noise in optical fibers represents the ultimate limit for fiber-based systems. However, at infrasonic frequencies, the spectral behavior of the intrinsic thermal noise is still unclear. In this letter, we present measurements of the fundamental thermal noise in optical fibers that are obtained using a balanced fiber Michelson interferometer. When an ultra-stable laser is used as the laser source and other noise sources are carefully controlled, the 1/f spectral density of the thermal noise is observed down to infrasonic frequencies, and the measured magnitude is consistent with the results of theoretical predictions at frequencies over the range from 0.2 Hz to 20 kHz. Moreover, as observed experimentally, the level of the 1/f thermal noise can be reduced by changing the coatings of the optical fibers. This therefore indicates one possible way to reduce thermal noise in optical fibers at low Fourier frequencies. Finally, the inconsistency between the experimental data and the existing theory for thermomechanical noise is discussed.
X-Ray Structures and Dynamic Solution Behaviours of Five-Coordinate Nickel(II) Complexes Containing Di- and Tritertiary Arsine Ligands
Authors: McMorran David A. , Fitzpatrick Michael G. , Cunninghame Robert G. , Downard Alison J. , Robinson Ward T. , Hanton Lyall R.
Published: January 2016

A comparative study of solid-state structures and dynamic solution behaviour of two homoleptic five-coordinate NiII complexes containing the potentially tridentate ligands bis(2-(dimethylarsino)phenyl)methylarsine (1) and bis(2-(dimethylarsino)phenyl)phenylarsine (2) and the bidentate ligand 1,2-bis(dimethylarsino)benzene (3) is reported. [Ni(1)2](ClO4)2 (4) crystallises in the monoclinic space group P21/n and adopts a pseudo-square-pyramidal structure. One of the ligands is bidentate with an –AsMe2 group dangling at 3.748 (5) Å from the central Ni. In solution the dangling –AsMe2 is found to rapidly exchange with the coordinated –AsMe2 group trans to it at lower temperatures and with all the coordinated –AsMe2 groups at higher temperatures. [Ni(2)2](PF6)2 (5) crystallizes as 5·C4H10O in the monoclinic space group P21/c and adopts a pseudo-trigonal-bipyramidal geometry. One of the ligands is bidentate and an –AsMe2 group dangles at 4.137 (8) Å from the central Ni, bisecting an As–Ni–As angle of the trigonal plane. Compound 5 shows fluxional behaviour similar to 4 but the barriers to exchange have higher energies. [Ni(3)2X](ClO4) [X = Br (6), Cl (7)] undergo rapid intermolecular axial halide exchange in solution. Compound 6 crystallises in the monoclinic space group Cc and has a distorted square-pyramidal structure consisting of pseudo-chains of cations with potentially bridging Br donors held at ~3.8 Å from the Ni of an adjacent cation by steric interaction with Me groups. The X-ray structure of [Ni(3)2Br2] (8), which crystallises in the monoclinic space group P21/n, is also reported. The complex has a tetragonally distorted octahedral structure, with long Ni–Br bonds, and approximates the proposed transition state for the rapid halide exchange process observed for 6.