bluuebunny/crossref_metadata_2025 huggingface dataset:
The first 3D and trinuclear cyano-bridged FeIII–FeIII(CN)6 complexes: structure and magnetic characterizations
Authors: Gungor Elif , Yahsi Yasemin , Kara Hulya , Caneschi Andrea
Published: March 2015

Crystal structures and magnetic properties of 3D cis-cyano-bridged and 2D trans-cyano-bridged trinuclear FeIII–FeIII(CN)6 structures are reported.
Ligand-assisted soft-chemical synthesis of self-assembled different shaped mesoporous Co3O4: efficient visible light photocatalysts
Authors: Roy Mouni , Ghosh Sourav , Naskar Milan Kanti
Published: March 2015

Mesoporous self-assembled cobalt oxide (Co3O4) of different shapes was synthesized by a facile soft-chemical process using cobalt nitrate, oxalic acid and phosphoric acid in the presence of cationic templates, cetyltrimethylammonium bromide, 1-butyl-3-methylimidazolium bromide, and pyridinium bromide at 75 °C/2 h followed by calcination at 300 °C.
Optimization of charge carrier transport balance for performance improvement of PDPP3T-based polymer solar cells prepared using a hot solution
Authors: Wang Jian , Zhang Fujun , Zhang Miao , Wang Wenbin , An Qiaoshi , Li Lingliang , Sun Qianqian , Tang Weihua , Zhang Jian
Published: March 2015

Using a hot solution may prove to be an effective method to improve the charge carrier transport for high performance PSCs.
Pentaborate(1−) salts templated by substituted pyrrolidinium cations: synthesis, structural characterization, and modelling of solid-state H-bond interactions by DFT calculations
Authors: Beckett Michael A. , Coles Simon J. , Davies R. Andrew , Horton Peter N. , Jones Charlotte L.
Published: March 2015

DFT calculations have shown that the α-reciprocal paired R22(8) H-bond interactions commonly found in the solid-state structures of pentaborate(1−) salts are strong (−21 kJ mol−1per H-bond).
Dehydrogenation of ammonia-borane by cationic Pd(ii) and Ni(ii) complexes in a nitromethane medium: hydrogen release and spent fuel characterization
Authors: Kim Sung-Kwan , Hong Sung-Ahn , Son Ho-Jin , Han Won-Sik , Michalak Artur , Hwang Son-Jong , Kang Sang Ook
Published: March 2015

This work provides a comprehensive experimental study on the mechanism of AB dehydrogenation with the [Pd(MeCN)4][BF4]2 (1) catalyst.
Combining remote sensing and eddy covariance data to monitor the gross primary production of an estuarine wetland ecosystem in East China
Authors: Wu Mingquan , Muhammad Shakir , Chen Fang , Niu Zheng , Wang Changyao
Published: March 2015

A new model performance better than the MODIS GPP product for wetland ecosystems was proposed and validated.
Extraction and separation of neodymium and dysprosium from used NdFeB magnets: an application of ionic liquids in solvent extraction towards the recycling of magnets
Authors: Riaño Sofía , Binnemans Koen
Published: March 2015

Neodymium, dysprosium and cobalt can be efficiently separated using a simple and environmentally friendly extraction system with ionic liquids.
Microfluidics-based single cell analysis reveals drug-dependent motility changes in trypanosomes
Authors: Hochstetter Axel , Stellamanns Eric , Deshpande Siddharth , Uppaluri Sravanti , Engstler Markus , Pfohl Thomas
Published: March 2015

Combination of microfluidics with optical tweezers is used in order to analyze the impact of drugs and chemicals on the motility of unicellular parasites.
Regioselective nucleophilic aromatic substitution reactions of 5,7-dinitroquinazoline-4-one and 5,7-dinitroquinazoline-4-thione with methylamine: a mechanistic consideration
Authors: Singh Amritpal , Goel Neetu
Published: March 2015

Thiocarbonyls, similar to carbonyls, are able to provide regioselective control for the attack of amines at the peri-position of 5,7-dinitroquinazoline-4-thione through intramolecular N–H–SC hydrogen bonding.
Synthesis, antitumor activity, and mechanism of action of 6-acrylic phenethyl ester-2-pyranone derivatives
Authors: Fang Sai , Chen Lei , Yu Miao , Cheng Bao , Lin Yongsheng , Morris-Natschke Susan L. , Lee Kuo-Hsiung , Gu Qiong , Xu Jun
Published: March 2015

The design for 6-acrylic phenethyl ester 2-pyranone derivatives against five tumor cell lines is reported.
An efficient solid-phase strategy for total synthesis of naturally occurring amphiphilic marine siderophores: amphibactin-T and moanachelin ala-B
Authors: Cherkupally Prabhakar , Ramesh Suhas , Govender Thavendran , Kruger Hendrik G. , de la Torre Beatriz G. , Albericio Fernando
Published: March 2015

The first total synthesis of the naturally obtainable marine siderophores amphibactin-T and moanachelin ala-B on solid-phase using standard Fmoc-chemistry is reported.
Conjugated microporous copolymer networks with enhanced gas adsorption
Authors: Yu Miao , Wang Xiaoyan , Yang Xiao , Zhao Yang , Jiang Jia-Xing
Published: March 2015

Conjugated microporous copolymer networks show a high specific surface area of up to 2241 m2 g−1 and a high CO2 uptake of 4.57 mmol g−1 (1.13 bar/273 K) with a H2 uptake of 2.24 wt% (1.13 bar/77.3 K).
Highly sensitive and selective chemosensors for Cu2+and Al3+based on photoinduced electron transfer (PET) mechanism
Authors: Chemate Santosh , Sekar Nagaiyan
Published: March 2015

Two new fluorescent PET chemosensors were synthesised from an acridine core. The sensors can be used to monitor Cu2+and Al3+in CH3CN. The detection limits for7a–Cu2+and7b–Al3+were calculated to be 2.8 × 10−7M and 5.8 × 10−7M, respectively.
Physical and biological activities of newly designed, macro-pore-structure-controlled 3D fibrous poly(ε-caprolactone)/hydroxyapatite composite scaffolds
Authors: Kim Minseong , Kim GeunHyung
Published: March 2015

A 3D fibrous scaffold using an electrohydrodynamic jet process supplemented with in vitro mineralization to obtain a hydroxyapatite layer in simulated body fluid was fabricated.
Synthesis of Ag–HNTs–MnO2 nanocomposites and their application for nonenzymatic hydrogen peroxide electrochemical sensing
Authors: Zhang Sai , Sheng Qinglin , Zheng Jianbin
Published: March 2015

Flower-like Ag–HNTs–MnO2 nanocomposites have been synthesized successfully and they were used for fabricating a non-enzymatic hydrogen peroxide (H2O2) sensor.
Targeted and controlled drug delivery using a temperature and ultra-violet responsive liposome with excellent breast cancer suppressing ability
Authors: Li Hua-Fei , Wu Cong , Xia Mao , Zhao He , Zhao Meng-Xin , Hou Jing , Li Rong , Wei Lixin , Zhang Li
Published: March 2015

Drug delivery systems (DDS) with favorable serum stability, high intra-tumor accumulation and tumor specific drug release are highly desired for promoting chemotherapeutic efficacy.
Bismuth-based nanoparticles as the environmentally friendly replacement for lead-based piezoelectrics
Authors: Esquivel-Gaon Margarita , Anguissola Sergio , Garry David , Gallegos-Melgar Adriana del C. , Saldaña Juan Muñoz , Dawson Kenneth A. , De Vizcaya-Ruiz Andrea , Del Razo Luz M.
Published: March 2015

BNT-BT is suitable non-toxic candidate to replace lead-based PZT, as they avoid leaching, imposing less risk during occupational and environmental exposure.
Global structure of C2B4H4: hypercloso or not
Authors: Zhang Xiao-yong , Ding Yi-hong
Published: March 2015

Through an extensive isomeric search utilizing a “skeleton-ligand” cluster-growth strategy, the global minimum of C2B4H4 is found to adopt a ribbon-like structure (01) rather than the previously reported hypercloso structure (04).
β-Substituted triarylborane appended porphyrins: photophysical properties and anion sensing
Authors: Sharma Rekha , Gautam Prabhat , Misra Rajneesh , Shukla Sanjeev K.
Published: March 2015

β-Substituted triarylborane porphyrins were designed and synthesized by the Pd-catalyzed Sonogashira cross-coupling reaction.
Correction: Chemical vapor infiltration tailored hierarchical porous CNTs/C composite spheres fabricated by freeze casting and their adsorption properties
Authors: Wang Junjie , Gong Qianming , Zhuang Daming , Liang Ji
Published: March 2015

Correction for ‘Chemical vapor infiltration tailored hierarchical porous CNTs/C composite spheres fabricated by freeze casting and their adsorption properties’ by Junjie Wang et al., RSC Adv., 2015, 5, 16870–16877.
Electrostatic swelling of bicontinuous cubic lipid phases
Authors: Tyler Arwen I. I. , Barriga Hanna M. G. , Parsons Edward S. , McCarthy Nicola L. C. , Ces Oscar , Law Robert V. , Seddon John M. , Brooks Nicholas J.
Published: March 2015

We have constructed swollen bicontinuous cubic lipid phases from monoglyceride, anionic lipid and cholesterol. These self-assembled systems have lattice parameters of almost 50 nm, over 4 times larger than archetypal lipid cubic phases.
Band engineering of AgSb1−xBixO3 for photocatalytic water oxidation under visible light
Authors: Ma Zuju , Wu Kechen , Sun Baozhen , He Chao
Published: March 2015

The incorporation of Bi into AgSbO3 to form a AgSb1−xBixO3 solid-solution for tuning the band gap for photocatalytic water splitting under sunlight.
Exceptional stability of Mg-implemented PbS quantum dot solar cells realized by galvanic corrosion protection
Authors: Park Joong Pill , Heo Jin hyuck , Im Sang Hyuk , Kim Sang-Wook
Published: March 2015

Mg-implemented PbS colloidal systems enhance the QD stability in air and their solar cell stability after EDT treatment.
Synergistic mediation of tumor signaling pathways in hepatocellular carcinoma therapy via dual-drug-loaded pH-responsive electrospun fibrous scaffolds
Authors: Yuan Ziming , Zhao Xin , Zhao Jingwen , Pan Guoqing , Qiu Wangwang , Wang Xiaohu , Zhu Yueqi , Zheng Qi , Cui Wenguo
Published: March 2015

A novel pH-sensitive electrospun composite PLLA fibrous scaffold was developed with long-term anti-cancer drug release and short-term anti-inflammation drug release for liver cancer therapy.
Achiral straight-rod liquid crystals indicating local biaxiality and ferroelectric switching behavior in the smectic A and nematic phases
Authors: Kishikawa Keiki , Inoue Takahiro , Hasegawa Naoshi , Takahashi Masahiro , Kohri Michinari , Taniguchi Tatsuo , Kohmoto Shigeo
Published: March 2015

Local biaxiality was realized through perfluoroarene–arene and CH/F interactions in the smectic A and nematic phases of rod-like compound 1a, and ferroelectric switching was observed.
Bioenergetic programming of macrophages by the apolipoprotein A-I mimetic peptide 4F
Authors: Datta Geeta , Kramer Philip A. , Johnson Michelle S. , Sawada Hirotaka , Smythies Lesley E. , Crossman David K. , Chacko Balu , Ballinger Scott W. , Westbrook David G. , Mayakonda Palgunachari , Anantharamaiah G. M. , Darley-Usmar Victor M. , Roger White C.
Published: March 2015

The apoA-I (apolipoprotein A-I) mimetic peptide 4F favours the differentiation of human monocytes to an alternatively activated M2 phenotype. The goal of the present study was to test whether the 4F-mediated differentiation of MDMs (monocyte-derived macrophages) requires the induction of an oxidative metabolic programme. 4F treatment induced several genes in MDMs that play an important role in lipid metabolism, including PPARγ (peroxisome-proliferator-activated receptor γ) and CD36. Addition of 4F was associated with a significant increase in FA (fatty acid) uptake and oxidation compared with vehicle treatment. Mitochondrial respiration was assessed by measurement of the OCR (oxygen-consumption rate). 4F increased basal and ATP-linked OCR as well as maximal uncoupled mitochondrial respiration. These changes were associated with a significant increase in ΔΨm (mitochondrial membrane potential). The increase in metabolic activity in 4F-treated MDMs was attenuated by etomoxir, an inhibitor of mitochondrial FA uptake. Finally, addition of the PPARγ antagonist T0070907 to 4F-treated MDMs reduced the expression of CD163 and CD36, cell-surface markers for M2 macrophages, and reduced basal and ATP-linked OCR. These results support our hypothesis that the 4F-mediated differentiation of MDMs to an anti-inflammatory phenotype is due, in part, to an increase in FA uptake and mitochondrial oxidative metabolism.
Microtubule association of EML proteins and the EML4-ALK variant 3 oncoprotein require an N-terminal trimerization domain
Authors: Richards Mark W. , O'Regan Laura , Roth Daniel , Montgomery Jessica M. , Straube Anne , Fry Andrew M. , Bayliss Richard
Published: March 2015

We present crystal structures of a trimeric coiled-coil domain found in echinoderm microtubule (MT)-associated protein (EMAP)-like (EML) proteins. This trimerization domain (TD) mediates self-association and interactions between a subset of EML proteins. MT-association of EML proteins requires the TD and an adjacent basic region.
Metformin and salicylate synergistically activate liver AMPK, inhibit lipogenesis and improve insulin sensitivity
Authors: Ford Rebecca J. , Fullerton Morgan D. , Pinkosky Stephen L. , Day Emily A. , Scott John W. , Oakhill Jonathan S. , Bujak Adam L. , Smith Brennan K. , Crane Justin D. , Blümer Regje M. , Marcinko Katarina , Kemp Bruce E. , Gerstein Hertzel C. , Steinberg Gregory R.
Published: March 2015

Metformin is the mainstay therapy for type 2 diabetes (T2D) and many patients also take salicylate-based drugs [i.e., aspirin (ASA)] for cardioprotection. Metformin and salicylate both increase AMP-activated protein kinase (AMPK) activity but by distinct mechanisms, with metformin altering cellular adenylate charge (increasing AMP) and salicylate interacting directly at the AMPK β1 drug-binding site. AMPK activation by both drugs results in phosphorylation of ACC (acetyl-CoA carboxylase; P-ACC) and inhibition of acetyl-CoA carboxylase (ACC), the rate limiting enzyme controlling fatty acid synthesis (lipogenesis). We find doses of metformin and salicylate used clinically synergistically activate AMPK in vitro and in vivo, resulting in reduced liver lipogenesis, lower liver lipid levels and improved insulin sensitivity in mice. Synergism occurs in cell-free assays and is specific for the AMPK β1 subunit. These effects are also observed in primary human hepatocytes and patients with dysglycaemia exhibit additional improvements in a marker of insulin resistance (proinsulin) when treated with ASA and metformin compared with either drug alone. These data indicate that metformin–salicylate combination therapy may be efficacious for the treatment of non-alcoholic fatty liver disease (NAFLD) and T2D.
Basic fibroblast growth factor induces VEGF expression in chondrosarcoma cells and subsequently promotes endothelial progenitor cell-primed angiogenesis
Authors: Tzeng Huey-En , Chen Po-Chun , Lin Kai-Wei , Lin Chih-Yang , Tsai Chun-Hao , Han Shao-Min , Teng Chieh-Lin , Hwang Wen-Li , Wang Shih-Wei , Tang Chih-Hsin
Published: March 2015

Chondrosarcoma, a common malignant tumour, develops in bone. Effective adjuvant therapy remains inadequate for treatment, meaning poor prognosis. It is imperative to explore novel remedies. Angiogenesis is a rate-limiting step in progression that explains neovessel formation for blood supply in the tumour microenvironment. Numerous studies indicate that EPCs (endothelial progenitor cells) promote angiogenesis and contribute to tumour growth. bFGF (basic fibroblast growth factor), a secreted cytokine, regulates biological activity, including angiogenesis, and correlates with tumorigenesis. However, the role of bFGF in angiogenesis-related tumour progression by recruiting EPCs in human chondrosarcoma is rarely discussed. In the present study, we found that bFGF induced VEGF (vascular endothelial growth factor) expression via the FGFR1 (fibroblast growth factor receptor 1)/c-Src/p38/NF-κB (nuclear factor κB) signalling pathway in chondrosarcoma cells, thereby triggering angiogenesis of endothelial progenitor cells. Our in vivo data revealed that tumour-secreted bFGF promotes angiogenesis in both mouse plug and chick CAM (chorioallantoic membrane) assays. Xenograft mouse model data, due to bFGF-regulated angiogenesis, showed the bFGF regulates angiogenesis-linked tumour growth. Finally, bFGF was highly expressed in chondrosarcoma patients compared with normal cartilage, positively correlating with VEGF expression and tumour stage. The present study reveals a novel therapeutic target for chondrosarcoma progression.
Thumbnail extraction for HEVC using prediction modes
Authors: Lee Wonjin , Jeon Gwanggil , Jeong Jechang
Published: March 2015

The existing thumbnail extraction method generates a thumbnail by reducing the reconstructed frame after a full decoding process. This method is complex and requires considerable time, particularly for higher resolution video. To alleviate these issues, a fast thumbnail extraction method which utilises an intra‐prediction mode for high‐efficiency video coding (HEVC) is presented. The proposed method reconstructs only the 4×4 boundary pixels needed for a thumbnail image based on the intra‐prediction mode. Experimental results indicate that the proposed method significantly reduces the computational complexity and extraction time for a thumbnail image. The visual quality of thumbnail images obtained with this method does not differ significantly from that of images extracted after a full decoding process.
Adaptive monotone fast iterative shrinkage thresholding algorithm for fluorescence molecular tomography
Authors: Fang Erxi , Wang Jiajun , Hu Danfeng , Zhang Jingya , Zou Wei , Zhou Yue
Published: March 2015

Fluorescence molecular tomography is an ill‐posed inverse problem. Considering the sparsity of the fluorescent source, authors proposed to alleviate this problem by including the L1‐norm regularisation term in the objective function. To obtain a solution to such an optimisation problem, an innovative version of the traditional over‐relaxation algorithm was proposed by including additional procedures for updating the step size and the regularisation parameter adaptively. Simulation results demonstrate that our proposed algorithm can improve the reconstruction accuracy and convergence speed effectively as compared with existed algorithms such as the perturbation algorithm and the over‐relaxation algorithm.
Structure and stability of solid Xe(H2)n
Authors: Somayazulu Maddury , Dera Przemyslaw , Smith Jesse , Hemley Russell J.
Published: March 2015

Mixtures of xenon and molecular hydrogen form a series of hexagonal, van der Waals compounds at high pressures and at 300 K. Synchrotron, x-ray, single crystal diffraction studies reveal that below 7.5 GPa, Xe(H2)8 crystallizes in a P3̄m1 structure that displays pressure-induced occupancy changes of two pairs of xenon atoms located on the 2c and 2d sites (while the third pair on yet another 2c site remains fully occupied). The occupancy becomes 1 at the P3̄m1 to R3 transition and all the xenon atoms occupy the 3d sites in the high-pressure structure. These pressure-induced changes in occupancy coincide with volume changes that maintain the average Xe:H2 stoichiometry fixed at 1:8. The synchrotron x-ray diffraction and Raman measurements show that this unique hydrogen-bearing compound that can be synthesized at 4.2 GPa and 300 K, quenched at low temperatures to atmospheric pressure, and retained up to 90 K on subsequent warming.
Nonlinear response in runoff magnitude to fluctuating rain patterns
Authors: Curtu R. , Fonley M.
Published: March 2015

The runoff coefficient of a hillslope is a reliable measure for changes in the streamflow response at the river link outlet. A high runoff coefficient is a good indicator of the possibility of flash floods. Although the relationship between runoff coefficient and streamflow has been the subject of much study, the physical mechanisms affecting runoff coefficient including the dependence on precipitation pattern remain open topics for investigation. In this paper, we analyze a rainfall-runoff model at the hillslope scale as that hillslope is forced with different rain patterns: constant rain and fluctuating rain with different frequencies and amplitudes. When an oscillatory precipitation pattern is applied, although the same amount of water may enter the system, its response (measured by the runoff coefficient) will be maximum for a certain frequency of precipitation. The significant increase in runoff coefficient after a certain pattern of rainfall can be a potential explanation for the conditions preceding flash-floods.
Engineering of high performance supercapacitor electrode based on Fe-Ni/Fe2O3-NiO core/shell hybrid nanostructures
Authors: Singh Ashutosh K. , Mandal Kalyan
Published: March 2015

The present work reports on fabrication and supercapacitor applications of a core/shell Fe-Ni/Fe2O3-NiO hybrid nanostructures (HNs) electrode. The core/shell Fe-Ni/Fe2O3-NiO hybrid nanostructures have been fabricated through a two step method (nanowire fabrication and their controlled oxidation). The 1D hybrid nanostructure consists of highly porous shell layer (redox active materials NiO and Fe2O3) and the conductive core (FeNi nanowire). Thus, the highly porous shell layer allows facile electrolyte diffusion as well as faster redox reaction kinetics; whereas the conductive FeNi nanowire core provides the proficient express way for electrons to travel to the current collector, which helps in the superior electrochemical performance. The core/shell Fe-Ni/Fe2O3-NiO hybrid nanostructures electrode based supercapacitor shows very good electrochemical performances in terms of high specific capacitance nearly 1415 F g−1 at a current density of 2.5 A g−1, excellent cycling stability and rate capability. The high quality electrochemical performance of core/shell hybrid nanostructures electrode shows its potential as an alternative electrode for forthcoming supercapacitor devices.
Theory of runaway electrons in ITER: Equations, important parameters, and implications for mitigation
Authors: Boozer Allen H.
Published: March 2015

The plasma current in ITER cannot be allowed to transfer from thermal to relativistic electron carriers. The potential for damage is too great. Before the final design is chosen for the mitigation system to prevent such a transfer, it is important that the parameters that control the physics be understood. Equations that determine these parameters and their characteristic values are derived. The mitigation benefits of the injection of impurities with the highest possible atomic number Z and the slowing plasma cooling during halo current mitigation to ≳40 ms in ITER are discussed. The highest possible Z increases the poloidal flux consumption required for each e-fold in the number of relativistic electrons and reduces the number of high energy seed electrons from which exponentiation builds. Slow cooling of the plasma during halo current mitigation also reduces the electron seed. Existing experiments could test physics elements required for mitigation but cannot carry out an integrated demonstration. ITER itself cannot carry out an integrated demonstration without excessive danger of damage unless the probability of successful mitigation is extremely high. The probability of success depends on the reliability of the theory. Equations required for a reliable Monte Carlo simulation are derived.
Mechanical and dynamical behaviors of ZrSi and ZrSi2 bulk metallic glasses: A molecular dynamics study
Authors: Ju Shin-Pon , Wu Tsang-Yu , Liu Shih-Hao
Published: March 2015

The mechanical and dynamical properties of ZrSi and ZrSi2 bulk metallic glasses (BMGs) have been investigated by molecular dynamics simulation. The Honeycutt-Anderson (HA) index analysis indicates that the major indexes in ZrSi and ZrSi2 bulk metallic glasses are 1551, 1541, and 1431, which refers to the liquid structure. For uniaxial tension, the results show that the ZrSi and ZrSi2 BMGs are more ductile than their crystal counterparts. The evolution of the distribution of atomic local shear strain clearly shows the initialization of shear transformation zones (STZs), the extension of STZs, and the formation of shear bands along a direction 45° from the tensile direction when the tensile strain gradually increases. The self-diffusion coefficients of ZrSi and ZrSi2 BMGs at temperatures near their melting points were calculated by the Einstein equation according to the slopes of the MSD profiles at the long-time limit. Because the HA fraction summation of icosahedral-like structures of ZrSi BMG is higher than that of ZrSi2 BMG, and these local structures are more dense, the self-diffusion coefficients of the total, Zr, and Si atoms of ZrSi2 BMG are larger than those of ZrSi BMG. This can be attributed to the cage effect, where a denser local structure has a higher possibility of atoms jumping back to form a backflow and then suppress atomic diffusivity. For ZrSi2 BMG, the self-diffusion coefficient of Si increases with temperature more significantly than does that of Zr, because more open packing rhombohedra structures are formed by the Si-Si pair.
Analysis of pinning in the linear AC response of anisotropic superconductors in oblique magnetic fields
Authors: Pompeo N.
Published: March 2015

The linear ac response of a pinned vortex system in uniaxial anisotropic superconductors is studied. The physical model for the interpretation of electrical transport experiments in the linear regime with arbitrary angles between the applied magnetic field, the applied current, and the anisotropy axis is provided. In particular, the pinning constant (also known as Labusch parameter) and Campbell resistivity tensors are derived for arbitrary orientations. The applicability to the various tensor quantities of the well-known angular scaling laws for the angular dependence on the field orientation in uniaxial superconductors is commented. Examples of data analysis based on the present results are provided.
Electron collisions with phenol: Total, integral, differential, and momentum transfer cross sections and the role of multichannel coupling effects on the elastic channel
Authors: da Costa Romarly F. , de Oliveira Eliane M. , Bettega Márcio H. F. , Varella Márcio T. do N. , Jones Darryl B. , Brunger Michael J. , Blanco Francisco , Colmenares Rafael , Limão-Vieira Paulo , García Gustavo , Lima Marco A. P.
Published: March 2015

We report theoretical and experimental total cross sections for electron scattering by phenol (C6H5OH). The experimental data were obtained with an apparatus based in Madrid and the calculated cross sections with two different methodologies, the independent atom method with screening corrected additivity rule (IAM-SCAR), and the Schwinger multichannel method with pseudopotentials (SMCPP). The SMCPP method in the Nopen-channel coupling scheme, at the static-exchange-plus-polarization approximation, is employed to calculate the scattering amplitudes at impact energies ranging from 5.0 eV to 50 eV. We discuss the multichannel coupling effects in the calculated cross sections, in particular how the number of excited states included in the open-channel space impacts upon the convergence of the elastic cross sections at higher collision energies. The IAM-SCAR approach was also used to obtain the elastic differential cross sections (DCSs) and for correcting the experimental total cross sections for the so-called forward angle scattering effect. We found a very good agreement between our SMCPP theoretical differential, integral, and momentum transfer cross sections and experimental data for benzene (a molecule differing from phenol by replacing a hydrogen atom in benzene with a hydroxyl group). Although some discrepancies were found for lower energies, the agreement between the SMCPP data and the DCSs obtained with the IAM-SCAR method improves, as expected, as the impact energy increases. We also have a good agreement among the present SMCPP calculated total cross section (which includes elastic, 32 inelastic electronic excitation processes and ionization contributions, the latter estimated with the binary-encounter-Bethe model), the IAM-SCAR total cross section, and the experimental data when the latter is corrected for the forward angle scattering effect [Fuss et al., Phys. Rev. A 88, 042702 (2013)].
Rayleigh-Bénard convection of cold water near its density maximum in a cubical cavity
Authors: Hu Yu-Peng , Li You-Rong , Wu Chun-Mei
Published: March 2015

In order to understand the characteristics of Rayleigh-Bénard convection of cold water near its density maximum in a cubical cavity with different thermal boundaries on the sidewalls, a series of direct numerical simulations were carried out by using the control volume approach. Flow pattern structures and their bifurcation series were detailedly analyzed through the bifurcation diagram, and the heat transfer ability of each branch was discussed. Results showed that both the flow pattern and heat transfer characteristic of Rayleigh-Bénard convection of cold water have many notable differences as compared with those of common fluids satisfying the Boussinesq approximation; the flow behavior depends both qualitatively and quantitatively on the thermal boundary conditions on the sidewalls. Furthermore, there are multiple flow pattern coexistence and hysteresis phenomenon during the flow pattern transition.
Electron and recoil ion momentum imaging with a magneto-optically trapped target
Authors: Hubele R. , Schuricke M. , Goullon J. , Lindenblatt H. , Ferreira N. , Laforge A. , Brühl E. , de Jesus V. L. B. , Globig D. , Kelkar A. , Misra D. , Schneider K. , Schulz M. , Sell M. , Song Z. , Wang X. , Zhang S. , Fischer D.
Published: March 2015

A reaction microscope (ReMi) has been combined with a magneto-optical trap (MOT) for the kinematically complete investigation of atomic break-up processes. With the novel MOTReMi apparatus, the momentum vectors of the fragments of laser-cooled and state-prepared lithium atoms are measured in coincidence and over the full solid angle. The first successful implementation of a MOTReMi could be realized due to an optimized design of the present setup, a nonstandard operation of the MOT, and by employing a switching cycle with alternating measuring and trapping periods. The very low target temperature in the MOT (∼2 mK) allows for an excellent momentum resolution. Optical preparation of the target atoms in the excited Li 22P3/2 state was demonstrated providing an atomic polarization of close to 100%. While first experimental results were reported earlier, in this work, we focus on the technical description of the setup and its performance in commissioning experiments involving target ionization in 266 nm laser pulses and in collisions with projectile ions.
Spin orientation, structure, morphology, and magnetic properties of hematite nanoparticles
Authors: Xu S. , Habib A. H. , Gee S. H. , Hong Y. K. , McHenry M. E.
Published: March 2015

Monodisperse hematite (α-Fe2O3) nanoparticles were synthesized by forced hydrolysis of acidic Fe3+ solution. Rietveld analysis was applied to the X-ray powder diffraction data to refine the lattice constants and atomic positions. The lattice constants for a hexagonal unit cell were determined to be a ∼ 0.50327 and c ∼ 1.37521 nm. High resolution transmission electron microscopy was employed to study the morphology of the particles. Atomic scale micrographs and diffraction patterns from several zone axes were obtained. These reveal the high degree of crystallinity of the particles. A series of observations made on the particles by tilting them through a range of ±45° revealed the particles to be micaceous with stacking of platelets with well defined crystallographic orientations. The Morin transition in these nanoparticles was found to occur at 210 K, which is lower temperature than 263 K of bulk hematite. It was ascertained from the previous Mössbauer studies that the spin orientation for nano-sized hematite particle flips from 90° to 28° with respect to the c-axis of the hexagonal structure during the Morin transition, which is in contrast to that observed in bulk hematite where spin orientation flips from 90° to 0°.
Inhomogeneous distribution of manganese atoms in ferromagnetic ZnSnAs2:Mn thin films on InP revealed by three-dimensional atom probe investigation
Authors: Uchitomi Naotaka , Inoue Hiroaki , Kato Takahiro , Toyota Hideyuki , Uchida Hiroshi
Published: March 2015

Atomic-scale Mn distributions in ferromagnetic ZnSnAs2:Mn thin films grown on InP substrates have been studied by applying three-dimensional atom probe (3DAP) microscopy. It is found that Mn atoms in cross-sectional 3DAP maps show the presence of inhomogeneities in Mn distribution, which is characteristic patterns of a spinoidal decomposition phase with slightly high and low concentration regions. The high Mn concentration regions are expected to be coherently clustered MnAs in the zinc-blende structure, resulting in the formation of Mn-As random connecting patterns. The origin of room-temperature ferromagnetism in ZnSnAs2:Mn on InP can be well explained by the formation of atomic-scale magnetic clustering by spinoidal decomposition without breaking the continuity of the zinc-blende structure, which has been suggested by previous theoretical works. The lattice-matching between magnetic epi-layers and substrates should be one of the most important factors to avoid the formation of secondary hexagonal MnAs phase precipitates in preparing ferromagnetic semiconductor thin films.
Micromagnetic study of interaction between achiral and homochiral domain walls in ultrathin ferromagnetic strips
Authors: Alejos Óscar , Martínez Eduardo
Published: March 2015

Magnetic domain walls have been repetitively proposed for its use in memory and logic devices. Most promising devices are based on ferromagnetic/heavy-metal bilayers, with perpendicular magnetic anisotropy. The characteristics of the walls in these devices are influenced by the strength of the Dzyaloshinskii-Moriya interaction. When this interaction is strong, it results in the formation of homochiral Néel walls, while its practical absence allows the formation of Bloch walls, either in parallel or antiparallel configurations. For isolated domain walls, a one-dimensional model can be successfully derived from the dynamic equations, which are of great help in order to understand their dynamics under different stimuli. However, a thorough study of the interactions between domain walls is required if such models are to be extended to two or more close walls. The present work studies the coexistence of two close nucleated domain walls by means of micromagnetic simulations, either in the case of Bloch walls, both parallel and antiparallel, or in the case of homochiral Néel walls, when a strong Dzyaloshinskii-Moriya interaction is present. Two interaction mechanisms between such walls have been revealed. The first one seems to be relevant for relatively distant walls as being inversely proportional to the square of distance, in rather agreement with the mechanism proposed by other authors. The second one, which can be straightly characterized in the case of Néel walls, has been estimated as inversely proportional to the fourth power of distance, then dominating for relatively close walls. Such dipolar-like interaction has been associated with the equivalent magnetic moments of domain walls. Finally, numerical simulations of the interaction in time of domain walls are shown, which can be appropriately explained by means of the mechanisms here described.
Neural coding using telegraphic switching of magnetic tunnel junction
Authors: Suh Dong Ik , Bae Gi Yoon , Oh Heong Sik , Park Wanjun
Published: March 2015

In this work, we present a synaptic transmission representing neural coding with spike trains by using a magnetic tunnel junction (MTJ). Telegraphic switching generates an artificial neural signal with both the applied magnetic field and the spin-transfer torque that act as conflicting inputs for modulating the number of spikes in spike trains. The spiking probability is observed to be weighted with modulation between 27.6% and 99.8% by varying the amplitude of the voltage input or the external magnetic field. With a combination of the reverse coding scheme and the synaptic characteristic of MTJ, an artificial function for the synaptic transmission is achieved.
Scaling and bounds in thermal conductivity of planar Gaussian correlated microstructures
Authors: Kale Sohan , Saharan Ankit , Koric Seid , Ostoja-Starzewski Martin
Published: March 2015

In this study 2d two phase microstructures closely resembling the experimentally captured micrographs of the interpenetrating phase composites are generated using a Gaussian correlation function based method. The scale dependent bounds on the effective thermal conductivity of such microstructures are then studied using Hill-Mandel boundary conditions. A scaling function is formulated to describe the transition from statistical volume element (SVE) to representative volume element (RVE), as a function of the mesoscale δ, the correlation length of the Gaussian correlation function λ, the volume fraction v, and the contrast k between the phases. The scaling function is determined through fitting the data from extensive simulations conducted over the parameter space. The scaling function shows that SVE approaches RVE as (δ/λ)−1.16. A material scaling diagram allows estimation of the RVE size, to within a chosen accuracy, of a given microstructure characterized by the correlation length of the Gaussian correlation function, contrast, and volume fraction of the phases.
Systematic comparison of crystalline and amorphous phases: Charting the landscape of water structures and transformations
Authors: Pietrucci Fabio , Martoňák Roman
Published: March 2015

Systematically resolving different crystalline phases starting from the atomic positions, a mandatory step in algorithms for the prediction of structures or for the simulation of phase transitions, can be a non-trivial task. Extending to amorphous phases and liquids which lack the discrete symmetries, the problem becomes even more difficult, involving subtle topological differences at medium range that, however, are crucial to the physico-chemical and spectroscopic properties of the corresponding materials. Typically, system-tailored order parameters are devised, like global or local symmetry indicators, ring populations, etc. We show that a recently introduced metric provides a simple and general solution to this intricate problem. In particular, we demonstrate that a map can be traced displaying distances among water phases, including crystalline as well as amorphous states and the liquid, consistently with experimental knowledge in terms of phase diagram, structural features, and preparation routes.
Injection locking of a two-mode electron oscillator with close frequencies
Authors: Starodubova E. N. , Usacheva S. A. , Ryskin N. M. , Novozhilova Y. V. , Nusinovich G. S.
Published: March 2015

Theory of injection locking is developed for a two-mode electron maser with close frequencies, when the driving signal affects both modes. There exist two regimes of phase locking in which either first or second mode dominates. Hard transitions between the two regimes are observed with variation of the driving frequency. The results of numerical simulations are presented for the case of driving by a signal with linear frequency chirp, as well as by a signal with sinusoidal frequency modulation. The effect of bifurcation delay is observed with the increase of chirp rate.
Understanding the distinctively skewed and heavy tailed character of atmospheric and oceanic probability distributions
Authors: Sardeshmukh Prashant D. , Penland Cécile
Published: March 2015

The probability distributions of large-scale atmospheric and oceanic variables are generally skewed and heavy-tailed. We argue that their distinctive departures from Gaussianity arise fundamentally from the fact that in a quadratically nonlinear system with a quadratic invariant, the coupling coefficients between system components are not constant but depend linearly on the system state in a distinctive way. In particular, the skewness arises from a tendency of the system trajectory to linger near states of weak coupling. We show that the salient features of the observed non-Gaussianity can be captured in the simplest such nonlinear 2-component system. If the system is stochastically forced and linearly damped, with one component damped much more strongly than the other, then the strongly damped fast component becomes effectively decoupled from the weakly damped slow component, and its impact on the slow component can be approximated as a stochastic noise forcing plus an augmented nonlinear damping. In the limit of large time-scale separation, the nonlinear augmentation of the damping becomes small, and the noise forcing can be approximated as an additive noise plus a correlated additive and multiplicative noise (CAM noise) forcing. Much of the diversity of observed large-scale atmospheric and oceanic probability distributions can be interpreted in this minimal framework.
Scaling law for crystal nucleation time in glasses
Authors: Mokshin Anatolii V. , Galimzyanov Bulat N.
Published: March 2015

Due to high viscosity, glassy systems evolve slowly to the ordered state. Results of molecular dynamics simulation reveal that the structural ordering in glasses becomes observable over “experimental” (finite) time-scale for the range of phase diagram with high values of pressure. We show that the structural ordering in glasses at such conditions is initiated through the nucleation mechanism, and the mechanism spreads to the states at extremely deep levels of supercooling. We find that the scaled values of the nucleation time, τ1 (average waiting time of the first nucleus with the critical size), in glassy systems as a function of the reduced temperature, T˜, are collapsed onto a single line reproducible by the power-law dependence. This scaling is supported by the simulation results for the model glassy systems for a wide range of temperatures as well as by the experimental data for the stoichiometric glasses at the temperatures near the glass transition.
Sound energy harvesting using an acoustic grating
Authors: Cui Xiao-Bin , Huang Cheng-Ping , Hu Jun-Hui
Published: March 2015

A sound energy harvester with an acoustic grating and a piezoelectric plate has been demonstrated. The acoustic grating consists of a metal slit grating and a thin flat metal screen. The metal slit grating can squeeze an incident acoustic wave into the air gap between the slit grating and metal screen, thus giving rise to high sound pressure and causing the metal screen to vibrate. Using the direct piezoelectric effect, the “squeezed” acoustic energy is harvested efficiently by a piezoelectric component that is mounted on the back of the metal screen.
Exchange bias mediated by interfacial nanoparticles (invited)
Authors: Berkowitz A. E. , Sinha S. K. , Fullerton E. E. , Smith D. J.
Published: March 2015

The objective of this study on the iconic exchange-bias bilayer Permalloy/CoO has been to identify those elements of the interfacial microstructure and accompanying magnetic properties that are responsible for the exchange-bias and hysteretic properties of this bilayer. Both epitaxial and polycrystalline samples were examined. X-ray and neutron reflectometry established that there existed an interfacial region, of width ∼1 nm, whose magnetic properties differed from those of Py or CoO. A model was developed for the interfacial microstructure that predicts all the relevant properties of this system; namely; the temperature and Permalloy thickness dependence of the exchange-bias, HEX, and coercivity, HC; the much smaller measured values of HEX from what was nominally expected; the different behavior of HEX and HC in epitaxial and polycrystalline bilayers. A surprising result is that the exchange-bias does not involve direct exchange-coupling between Permalloy and CoO, but rather is mediated by CoFe2O4 nanoparticles in the interfacial region.
Efficiency analysis of magnetic resonance wireless power transfer with three-dimensional transmitters
Authors: Zhao J. F. , Huang X. L. , Wang W.
Published: March 2015

Generally, the transfer power of wireless power transfer (WPT) system reduces significantly with the increase of distance and angle between transmitting and receiving coils in traditional WPT system. Experiments with two transmitters in the magnetic resonance coupling WPT system have been shown that it can enlarge transfer power and create a stable region in power transfer efficiency in a certain space. However, two transmitters have a limited transfer power comparing to the three-dimensional WPT. In this paper, a model of WPT system with three-dimensional transmitters (3DT-WPT), which are perpendicular to each other and so cover three dimensional spaces, is proposed to overcome the drawbacks mentioned above and the 3DT-WPT system via magnetic resonance coupling is designed to verify the proposed model. The diversity of the characteristics of the transfer power is observed through changing the distance and normal angle between transmitting and receiving coils. Analysis and experiment results show that the proposed method has better performance than the two transmitters.
Interferometric properties of standing spin waves and the application to a phase comparator
Authors: Ya X. , Chen H. , Oyabu S. , Peng B. , Otsuki H. , Tanaka T. , Matsuyama K.
Published: March 2015

We numerically studied the material and structural parameter dependence of interferometric properties of the standing spin wave resonance (SSWR) by micromagnetic simulations and demonstrate the feasibility of practical application to an integrated phase comparator. The micromagnetic configuration of the synthesized SSWR emitted from the two microwave currents flowing through the parallel strip lines depends on the phase difference Δϕ between them. Resultantly, the Δϕ is converted to the related output voltage with an overlaid phase detector, inductively coupled to the magnetic strip. Among the investigated various material systems, low damping (α ∼ 0.001) metallic ferromagnets are found to exhibit superior device performance due to the reduced viscous dissipation.
Unusual nonlinear current-voltage characteristics of a metal-intrinsic semiconductor-metal barrierless structure
Authors: Meriuts A. V. , Gurevich Yu. G.
Published: March 2015

A nonlinear model for the electric current in a metal-intrinsic semiconductor-metal structure without potential barriers in contacts is considered using a drift diffusion approach. An analytical solution of the continuity equations and the current-voltage characteristic for various recombination rates in the contacts are obtained. It is shown that the current-voltage characteristics of such a structure exhibit not only linear behavior, corresponding to Ohm's law, but may also possess properties of current-voltage characteristics of the rectifier diode. It is also possible current-voltage characteristics with saturation in both forward and backward directions. Physical model that explains the obtained results is proposed.
Effects of magnetocrystalline anisotropy and magnetization saturation on the mechanically induced switching in nanomagnets
Authors: Yi Min , Xu Bai-Xiang , Shen Zhigang
Published: March 2015

The effects of magnetocrystalline anisotropy (Ku) and magnetization saturation (Ms) on the mechanically induced switching in nanomagnets are studied using a constraint-free phase field model, which allows explicit magneto-mechanical coupling and strictly constant magnetization magnitude. The effects of Ku and Ms on the transition boundary between the coherent and incoherent switching modes are presented in terms of the nanomagnet geometry. It is found that Ms rather than Ku can affect the transition boundary between the two switching modes. In the coherent mode, there exists a critical strain (εc) to induce a deterministic 90° switching. By using the dynamic nature and overrun behavior of the magnetization, a deterministic 180° switching can occur if the mechanical strain is removed once the magnetization rotates to the largest achievable angle (ϑ1m). For 90° switching, increasing Ku can enhance both εc and ϑ1m, whereas Ms incurs no noticeable changes. For 180° switching, the switching time (ts) increases with Ms linearly, but initially decreases with increasing Ku and then saturates. The results for ts suggest that moderate Ku and Ms are advisable to simultaneously obtain relatively low εc, quick switching, high storage density, and high magnetization-state stability in nanomagnets. This work provides insight on tuning mechanically assisted nanomagnet-based logic and memory devices through Ms and Ku.