bluuebunny/crossref_metadata_2025 huggingface dataset:
Substituted 4-oxo-crotonic acid derivatives as a new class of protein kinase B (PknB) inhibitors: synthesis and SAR study
Authors: Xu Changliang , Bai Xiaoguang , Xu Jian , Ren Jinfeng , Xing Yun , Li Ziqiang , Wang Juxian , Shi Jingjing , Yu Liyan , Wang Yucheng
Published: January 2017

Structure–activity relationship (SAR) study of a series of unsaturated crotonic acid derivatives as potential PknB inhibitors.
Band gap tuning from an indirect EuGa2S4 to a direct EuZnGeS4 semiconductor: syntheses, crystal and electronic structures, and optical properties
Authors: Chi Yang , Guo Sheng-Ping , Xue Huai-Guo
Published: January 2017

Novel EuZnGeS4, with a direct band gap, can be obtained via simple substitution from EuGa2S4, with an indirect band gap.
Luminescent properties of benzothiazole derivatives and their application in white light emission
Authors: Lu Fengxian , Hu Rui , Wang Shuangqing , Guo Xudong , Yang Guoqiang
Published: January 2017

A saturated white-light emission was obtained by dispersing three benzothiazole analogues into a solid PMMA matrix. This skillfully avoids the detrimental energy transfer between doped dyes providing a simple approach for fabrication of white-light emitting devices.
NiO@MnO2 core–shell composite microtube arrays for high-performance lithium ion batteries
Authors: Zhong Yuan , Huang Huan , Wang Kai , He Zhishun , Zhu Shasha , Chang Ling , Shao Haibo , Wang Jianming , Cao Chu-nan
Published: January 2017

The NiO@MnO2 core–shell microtube array electrode with excellent lithium storage performance is fabricated by self-corrosion and electrodeposition.
Elucidating the binding interaction of andrographolide with the plasma proteins: biophysical and computational approach
Authors: Yeggoni Daniel Pushparaju , Kuehne Christian , Rachamallu Aparna , Subramanyam Rajagopal
Published: January 2017

A phytochemical andrographolide is an anticancer agent with a stable conformation that strongly binds to the plasma proteins.
In situ TEMPO surface functionalization of nanocellulose membranes for enhanced adsorption of metal ions from aqueous medium
Authors: Karim Zoheb , Hakalahti Minna , Tammelin Tekla , Mathew Aji P.
Published: January 2017

The current work demonstrates an innovative approach to develop nanocellulose based membranes via in situ TEMPO functionalization of the thin functional layer of cellulose nanocrystals (CNCBE) to enhance the metal ion adsorption capacity.
Nano KF/Al2O3 particles as an efficient catalyst for no-glycerol biodiesel production by coupling transesterification
Authors: Tang Ying , Ren Haomiao , Chang Feiqin , Gu Xuefan , Zhang Jie
Published: January 2017

In this study no-glycerol biodiesel production was prepared using nano γ-Al2O3 particles as support in the tri-component coupling transesterification of canola oil, dimethyl carbonate and methanol.
Impregnation of zinc oxide modified clay over alginate beads: a novel material for the effective removal of congo red from wastewater
Authors: Vahidhabanu Shappur , Karuppasamy D. , Adeogun Abideen Idowu , Babu B. Ramesh
Published: January 2017

Alginate hydrogel beads were impregnated with zinc oxide (ZnO) modified sepiolite clay and applied for the removal of congo red (CR) dye from its aqueous solution in batch and packed column systems.
One step synthesis of Ni/Ni(OH)2 nano sheets (NSs) and their application in asymmetric supercapacitors
Authors: Ede Sivasankara Rao , Anantharaj S. , Kumaran K. T. , Mishra Soumyaranjan , Kundu Subrata
Published: January 2017

Ni/Ni(OH)2 NSs were prepared by a facile hydrothermal method using EtOH as reducing agent. Asymmetric device is fabricated using AC and Ni/Ni(OH)2 NSs as electrodes, with optimized specific capacitance of 62 F g−1 and a maximum energy density of 23.45 W h kg−1.
Geometrical and electronic structures of small Co–Mo nanoclusters
Authors: Xie Xuefang , Sun Jun , Cao Biaobing , Duan Haiming
Published: January 2017

The geometries, energetics and electronic structures of Co13, Mo13, Co12Mo and Mo12Co clusters are systematically investigated by using the first principles method combined with a genetic algorithm.
Improved viscoelastic, thermal, and mechanical properties of in situ microfibrillar polypropylene/polyamide 6,6 composites via direct extrusion using a triple-screw extruder
Authors: Huang Ying , He Yadong , Ding Weidan , Yang Kunxiao , Yu Dongquan , Xin Chunling
Published: January 2017

Improved viscoelastic, thermal, and mechanical properties ofin situmicrofibrillar polypropylene/polyamide 6,6 compositesviadirect extrusion using a triple-screw extruder.
Facile fabrication of nanoporous graphene powder for high-rate lithium–sulfur batteries
Authors: Zhuang Huajie , Deng Wei , Wang Wei , Liu Zhaoping
Published: January 2017

High quality and high quantity nanoporous graphene powder has been successfully prepared for high-rate lithium–sulfur battery applications.
Diameter effect of gold nanoparticles on photothermal conversion for solar steam generation
Authors: Guo Ankang , Fu Yang , Wang Gang , Wang Xianbao
Published: January 2017

The diameter effect of Au NPs on photothermal conversion was explored for generating solar steam.
A facile sacrificial template method to synthesize one-dimensional porous CdO/CdFe2O4 hybrid nanoneedles with superior adsorption performance
Authors: Wu Yadan , Hu Enlai , Dai Wei , Li Zhipeng , Zhong Yijun , Hu Yong
Published: January 2017

A novel adsorbent based on 1D porous CdO/CdFe2O4 hybrid nanoneedles has been firstly synthesized via a facile sacrificial template (solid Cd2Fe(CN)6) method, which exhibit an superior adsorption capacity of 1491 mg g−1 for CR from aqueous solution.
A four-state capacitance molecular switch based on a redox active tetrathiafulvalene self-assembled monolayer
Authors: Marchante E. , Maglione M. S. , Crivillers N. , Rovira C. , Mas-Torrent M.
Published: January 2017

A tetrathiafulvalene self-assembled monolayer has been successfully exploited as a 4-state electrochemical switch using the capacitance as output signal.
Thermo-reversible sol–gel transition of aqueous solutions of patchy polymers
Authors: Parmar Indravadan A. , Shedge Aarti S. , Badiger Manohar V. , Wadgaonkar Prakash P. , Lele Ashish K.
Published: January 2017

Aqueous solutions of an amphiphilic thermoreversible patchy polymer show abrupt gelation upon cooling by the combined effect of percolation and transition from intra to intermolecular hydrophobic associations.
Synthesis of homochiral zeolitic metal–organic frameworks with amino acid and tetrazolates for chiral recognition
Authors: Li Min-Yu , Wang Fei , Gu Zhi-Gang , Zhang Jian
Published: January 2017

By mixing amino acids and tetrazolate ligands, a series of homochiral zeolitic metal–organic frameworks (ZMOFs) with ABW topology have been synthesized, which show permanent microporosity and potential enantioselective recognition ability.
Induction of potent apoptosis by an anti-CD20 aptamer via the crosslink of membrane CD20 on non-Hodgkin's lymphoma cells
Authors: Wu Cong , Wan Wei , Zhu Ji , Jin Hai , Zhao Tiejun , Li Huafei
Published: January 2017

An anti-CD20 DNA aptamer was successfully generated by cell-SELEX, the crosslink of which can induce potent apoptosis in target cells.
Catalytic performance of gallium oxide based-catalysts for the propane dehydrogenation reaction: effects of support and loading amount
Authors: Shao Chun-Tao , Lang Wan-Zhong , Yan Xi , Guo Ya-Jun
Published: January 2017

Ga2O3-based catalysts supported on different supports (ZSM-5, SBA-15, γ-Al2O3 and SiO2) were prepared, and the effects of supports and Ga2O3 content (1–9 wt%) on their catalytic performance for the propane dehydrogenation reaction were discussed.
First-principles study of Zr–N crystalline phases: phase stability, electronic and mechanical properties
Authors: Yu Shuyin , Zeng Qingfeng , Oganov Artem R. , Frapper Gilles , Huang Bowen , Niu Haiyang , Zhang Litong
Published: January 2017

Using a variable-compositionab initioevolutionary algorithm, we investigate stability of various Zr–N compounds.
Auxetic mechanical metamaterials
Authors: Kolken H. M. A. , Zadpoor A. A.
Published: January 2017

We review the topology–property relationship and the spread of Young's modulus–Poisson's ratio duos in three main classes of auxetic metamaterials.
Stimuli-responsive hyperbranched poly(amidoamine)s integrated with thermal and pH sensitivity, reducible degradability and intrinsic photoluminescence
Authors: Zhan Chen , Fu Xiao-Bin , Yao Yefeng , Liu Hua-Ji , Chen Yu
Published: January 2017

Stimuli-responsive HPA-C4s integrated with thermal and pH sensitivity, reducible degradability and intrinsic photoluminescence were successfully prepared and characterized.
Ansavaricins A–E: five new streptovaricin derivatives from Streptomyces sp. S012
Authors: Zhang Zhiqiang , Zhang Juanli , Song Rentai , Guo Zhixing , Wang Haoxin , Zhu Jing , Lu Chunhua , Shen Yuemao
Published: January 2017

Five new polyketides of the ansamycin class, named ansavaricins A–E (1–5), together with three known streptovaricins 6–8, were isolated from the Streptomyces sp. S012 strain.
Large electrocaloric strength and broad electrocaloric temperature span in lead-free Ba0.85Ca0.15Ti1−xHfxO3ceramics
Authors: Wang Xiangjian , Wu Jiagang , Dkhil Brahim , Zhao Chunlin , Li Tangyuan , Li Wei , Lou Xiaojie
Published: January 2017

The electrocaloric (EC) effect of Ba0.85Ca0.15Ti1−xHfxO3 (abbreviated as: BCTHx) ceramics has been systematically investigated using an indirect method.
Preparation of TiO2/Ti3C2Tx hybrid nanocomposites and their tribological properties as base oil lubricant additives
Authors: Xue Maoquan , Wang Zhiping , Yuan Feng , Zhang Xianghua , Wei Wei , Tang Hua , Li Changsheng
Published: January 2017

TiO2/Ti3C2Tx hybrid nanocomposites were successfully prepared by a liquid phase synthesis technology. The hybrid nanocomposites improve the tribological properties of base oil by mending the surface and formation a uniform tribofilm on the surface.
Hydrophobic mixed solvent induced PLGA-based in situ forming systems for smooth long-lasting delivery of Radix Ophiopogonis polysaccharide in rats
Authors: Wang LiNa , Lin Xiao , Hong YanLong , Shen Lan , Feng Yi
Published: January 2017

To obtain a sustainedin vivorelease of Radix Ophiopogonis polysaccharide, hydrophobic solvent-inducedin situforming systems were investigated, including the factors affecting drug release and anti-myocardial ischemic activity of a formulation.
Mechanistic insight into the selective olefin-directed oxidative carbocyclization and borylation by a palladium catalyst: a theoretical study
Authors: Zheng Xiao-Wen , Nie Ling , Li Ya-Ping , Liu Shao-Jing , Zhao Feng-Yue , Zhang Xin-Yu , Wang Xing-Dong , Liu Tao
Published: January 2017

Lowering the polarity of the solvent disfavors the olefin insertion step and the formation of cyclobuteneboron product.
Highly effective removal of malachite green from aqueous solution by hydrochar derived from phycocyanin-extracted algal bloom residues through hydrothermal carbonization
Authors: Zhang Hong , Zhang Fayu , Huang Qing
Published: January 2017

Huge volumes of harmful algal bloom residues (ABR) are collected during emergency treatment of cyanobacteria blooms, and phycocyanin-extracted algal bloom residues (PE-ABR) are produced after extraction of phycocyanin from ABR.
Scaling up single-wall carbon nanotube laser annealing: effect on electrical resistance and hydrogen adsorption
Authors: Souza Nicolas , Roble Martín , Diaz-Droguett Donovan E. , Mücklich Frank
Published: January 2017

Electrical resistance and hydrogen adsorption of laser-annealed single-wall carbon nanotube mats.
Lipase immobilization on facile synthesized polyaniline-coated silver-functionalized graphene oxide nanocomposites as novel biocatalysts: stability and activity insights
Authors: Asmat Shamoon , Husain Qayyum , Azam Ameer
Published: January 2017

Schematic representation of the preparation of PANI/Ag/GO-NCs and immobilization of lipase.
Design and characterization of methoxy modified organic semiconductors based on phenyl[1]benzothieno[3,2-b][1]benzothiophene
Authors: Yao Chao , Chen Xiaolong , He Yaowu , Guo Yitong , Murtaza Imran , Meng Hong
Published: January 2017

Two environmentally and thermally stable [1]benzothieno[3,2-b][1]benzothiophene (BTBT) derivatives, BOP-BTBT and DBOP-BTBT are successfully synthesized and analyzed as active layers in organic thin film transistors.
First total synthesis of the only known 2-isopropyliden-2H-benzofuran-3-one isolated from V. luetzelburgii
Authors: Pergomet Jorgelina L. , Larghi Enrique L. , Kaufman Teodoro S. , Bracca Andrea B. J.
Published: January 2017

The first total synthesis of the unique isopropyliden-2H-benzofuran-3-one, isolated from Verbesina luetzelburgii, is reported in racemic and a chiral form.
A new H2S-specific near-infrared fluorescence-enhanced probe that can visualize the H2S level in colorectal cancer cells in mice
Authors: Zhang Kun , Zhang Jie , Xi Zhen , Li Lu-Yuan , Gu Xiangxiang , Zhang Qiang-Zhe , Yi Long
Published: January 2017

A highly sensitive H2S-specific near-infrared fluorescence-enhanced probe was developed for real-time imaging of endogenous H2S in colorectal cancer cells (HCT116 and HT29) in mice.
Multifunctional porous organic polymers embedded with magnetic nanoparticles
Authors: Qiao Shanlin , Huang Wei , Wang Ting , Du Bin , Chen Xiangning , Hameed Abdul , Yang Renqiang
Published: January 2017

Magnetism, a conjugated π-system and ultramicropores are combined in one multifunctional bulk material with a core@shell structure for dynamic and static pollutant treatment.
Applying the heteroatom effect of chalcogen for high-performance small-molecule solar cells
Authors: Zhou Zichun , Xu Shengjie , Liu Wenrui , Zhang Cheng , Hu Qin , Liu Feng , Russell Thomas P. , Zhu Xiaozhang
Published: January 2017

Three donor materials STB-C, STB-O and STB-S were synthesized for a deep understanding of the heteroatom effect of chalcogen on OSC performance.
Large-area assembly of halloysite nanotubes for enhancing the capture of tumor cells
Authors: He Rui , Liu Mingxian , Shen Yan , Long Zheru , Zhou Changren
Published: January 2017

Here, polystyrene sulfonate sodium (PSS) modified halloysite nanotubes were self-assembled into patterned coating on a glass substrate with ordered nanotube arrays for capture of tumor cells.
An aza-BODIPY photosensitizer for photoacoustic and photothermal imaging guided dual modal cancer phototherapy
Authors: Tang Qianyun , Si Weili , Huang Chuhan , Ding Kaikai , Huang Wei , Chen Peng , Zhang Qi , Dong Xiaochen
Published: January 2017

A novel NIR absorbing aza-BODIPY photosensitizer with high 1O2 quantum yield and excellent photothermal conversion efficiency was designed for synergistic phototherapy.
Turning a disadvantage into an advantage: synthesizing high-quality organometallic halide perovskite nanosheet arrays for humidity sensors
Authors: Ren Kuankuan , Huang Le , Yue Shizhong , Lu Shudi , Liu Kong , Azam Muhammad , Wang Zhijie , Wei Zhongming , Qu Shengchun , Wang Zhanguo
Published: January 2017

A humidity sensor made of uniform perovskite nanosheet arrays displayed good performance, and hence represents a new application for perovskite materials.
Palladacycles of sulfated and selenated Schiff bases of ferrocene-carboxaldehyde as catalysts for O-arylation and Suzuki–Miyaura coupling
Authors: Sharma Alpesh K. , Joshi Hemant , Bhaskar Renu , Kumar Satyendra , Singh Ajai K.
Published: January 2017

Palladacycles of Schiff-bases having a ferrocene core catalyzeO-arylation of ArBr and Suzuki–Miyaura coupling of ArBr/Cl with a yield up to 93%.
Silver-mediated radical coupling reaction of isocyanides and alcohols/phenols in the presence of water: unprecedented hydration and radical coupling reaction sequence
Authors: Zhang Lin , Xiao Pin , Guan Xiaoxue , Huang Zhouliang , Zhang Jingping , Bi Xihe
Published: January 2017

The first radical coupling of isocyanides and alcohols/phenols promoted by silver in the presence of water is reported.
Correction: Amphiphilic and double hydrophilic block copolymers containing a polydehydroalanine block
Authors: Billing Mark , Festag Grit , Bellstedt Peter , Schacher Felix H.
Published: January 2017

Correction for ‘Amphiphilic and double hydrophilic block copolymers containing a polydehydroalanine block’ by Mark Billing et al., Polym. Chem., 2017, DOI: 10.1039/c6py02076c.
Assembly of the elongated collagen prolyl 4-hydroxylase α2β2 heterotetramer around a central α2 dimer
Authors: Koski M. Kristian , Anantharajan Jothi , Kursula Petri , Dhavala Prathusha , Murthy Abhinandan V. , Bergmann Ulrich , Myllyharju Johanna , Wierenga Rik K.
Published: January 2017

Collagen prolyl 4-hydroxylase (C-P4H), an α2β2 heterotetramer, is a crucial enzyme for collagen synthesis. The α-subunit consists of an N-terminal dimerization domain, a central peptide substrate-binding (PSB) domain, and a C-terminal catalytic (CAT) domain. The β-subunit [also known as protein disulfide isomerase (PDI)] acts as a chaperone, stabilizing the functional conformation of C-P4H. C-P4H has been studied for decades, but its structure has remained elusive. Here, we present a three-dimensional small-angle X-ray scattering model of the entire human C-P4H-I heterotetramer. C-P4H is an elongated, bilobal, symmetric molecule with a length of 290 Å. The dimerization domains from the two α-subunits form a protein–protein dimer interface, assembled around the central antiparallel coiled-coil interface of their N-terminal α-helices. This region forms a thin waist in the bilobal tetramer. The two PSB/CAT units, each complexed with a PDI/β-subunit, form two bulky lobes pointing outward from this waist region, such that the PDI/β-subunits locate at the far ends of the βααβ complex. The PDI/β-subunit interacts extensively with the CAT domain. The asymmetric shape of two truncated C-P4H-I variants, also characterized in the present study, agrees with this assembly. Furthermore, data from these truncated variants show that dimerization between the α-subunits has an important role in achieving the correct PSB–CAT assembly competent for catalytic activity. Kinetic assays with various proline-rich peptide substrates and inhibitors suggest that, in the competent assembly, the PSB domain binds to the procollagen substrate downstream from the CAT domain.
Bone marrow mesenchymal stem cells inhibit dendritic cells differentiation and maturation by microRNA-23b
Authors: Wu Jingguo , Ji Chengbo , Cao Feifei , Lui Hongfen , Xia Bo , Wang Lanping
Published: January 2017

Research on regulation and its mechanism of bone marrow mesenchymal stem cells (BMSCs) on dendritic cells (DCs), which is the initiating factor in immune response has applicable clinical value. Although BMSCs have a significant regulatory effect on the maturation of DCs, its molecular mechanism is still unclear. BMSCs and DCs, were co-cultured by different concentration ratios. Flow cytometry was used to detect the expression of DC markers (CD83, CD11c). Quantitative reverse transcription PCR (qRT-PCR) was used to measure the expression of related genes in RNA level. Expression of the target proteins was detected with using Western blot assay. miRNA inhibitor and miRNA mimic were used to suppress and up-regulate the expression of the target gene. In this research, our results demonstrated that BMSCs notably inhibited maturation of DCs in the co-culture system of BMSCs and DCs and confirmed that this inhibition is due to overexpression of miR-23b. Furthermore, this research found that miR-23b overexpression inhibited the expression of p50/p65, thus blocked the activation of the NF-κB pathway. In conclusion, BMSCs affected the activation of NF-κB pathway through miR-23b overexpression resulting in inhibition of the maturation and differentiation of DCs.
Full‐wave analytical explicit expressions for the surface fields of an electrically large horizontal circular loop antenna placed on a layered ground
Authors: Parise Mauro
Published: January 2017

This study presents full‐wave analytical explicit expressions for the time‐harmonic surface fields of a large horizontal circular loop antenna located on a multilayer Earth. The expressions are derived by applying the following procedure. First, the complete integral representations for the EM field components are decomposed into three parts, that is, the residue contributions from the poles of the integrands and the two branch‐cut integrals associated with the wavenumbers in free‐space and in the bottom layer of the stratified medium. Next, the square‐root term that generates the branch cut is extracted from the integrand of the generic branch‐cut integral. Finally, the square‐root algorithm‐based partial fraction expansion is applied to each extracted square‐root term, so as to convert the branch‐cut integrals into closed‐contour integrals around a set of pole singularities, which can be straightforwardly evaluated. As a result of the developed procedure, the fields are expressed as convergent sums of special functions. Numerical results are presented to validate the proposed formulation. In addition to being accurate, the derived formulas offer advantages in terms of computation time over standard numerical integration techniques.
Ka‐band RF MEMS capacitive switch with low loss, high isolation, long‐term reliability and high power handling based on GaAs MMIC technology
Authors: Chu Chenlei , Liao Xiaoping , Yan Hao
Published: January 2017

This study presents a Ka‐band radio frequency (RF) micro electro mechanical systems (MEMS) capacitive switch with low loss, high isolation, long‐term reliability and high power handling based on GaAs microwave monolithic integrated circuit (MMIC) technology. In this design, a T‐matching structure is employed to realise impendence matching at ‘up‐state’ by modifying the dimensions of centre signal line. Thus, the reflection loss and insertion loss are improved effectively. Measurement results show that in ‘up‐state’ position, the input reflection coefficient (S11) is less than −20.4 dB with the forward transmission coefficient (S21) of better than −0.27 dB at Ka‐band (27–40 GHz). At ‘down‐state’, the switch is designed in a state of self‐resonance to obtain high isolation. The measured isolation is better than 20 dB over Ka‐band and can reach 35 dB at its self‐resonant frequency of 35 GHz. The measured actuation voltage is about 36 V. The measured lifetime is at least 5.76 × 107 cycles. The measured power handling capability can reach up to 39 dBm. The proposed compact RF MEMS capacitive switch possesses excellent performances in terms of low insertion loss, high isolation, long lifetime and high power handling capability.
Analysis on radiation of antenna mounted on perfectly conducting convex surfaces by using NURBS‐UTD method
Authors: Wang Nan , Dang Xiaojie , Yuan Haobo , Liang Changhong
Published: January 2017

This paper studies the use of NURBS‐UTD method in analyzing radiation of antenna set on perfectly conducting convex surfaces. The electromagnetic ray path is traced by numerical algorithm built from parametric domain in order to take advantage of the mapping definition for parametric surfaces. The presented algorithm can be applied to arbitrary shaped surfaces and provide accurate and stable geometrical parameters to calculation of electromagnetic fields afterwards. The algorithm is verified by cylinder on which analytical solution of ray path is available and good agreement is achieved by comparison. Radiation patterns of antennas mounted on arbitrary shaped surfaces are calculated and compared to commercial software to testify the accuracy and ability of the presented method. Evaluated by RMS error, the deviation between the presented method and commercial software is about 1 dB.
Adaptive controller for an MTPA IPMSM drive system without using a high‐frequency sinusoidal generator
Authors: Liu Tian‐Hua , Chen Yi , Wu Meng‐Jhe , Dai Bo‐Chen
Published: January 2017

A maximum torque/ampere (MTPA) interior permanent magnet synchronous motor (IPMSM) drive system that does not require a high‐frequency sinusoidal generator is proposed. By using a band‐pass filter, the high‐frequency variation of the output mechanical power, which is proportional to the slope of torque to advance angle, can be obtained. After that, the high‐frequency variation of the output mechanical power and the amplitude of the stator current vector are inputted into a fuzzy‐logic controller. By using the fuzzy‐logic controller, the advance angle of the MTPA for an IPMSM can be automatically determined. In addition, an adaptive speed controller is designed to improve the transient responses, load disturbance responses, and tracking responses of the closed‐loop MTPA drive system. A digital signal processor, TMS‐320LF‐2812, is used as the control centre to execute the adaptive speed controller and the MTPA searching algorithm. Experimental results validate the correctness and feasibility of the proposed method. The proposed drive system can be applied for air conditioners, adjustable speed fans, and other industry drives.
Hystereses in dwarf nova outbursts and low-mass X-ray binaries
Authors: Hameury J.-M. , Lasota J.-P. , Knigge C. , Körding E. G.
Published: January 2017

Context. The disc instability model (DIM) successfully explains why many accreting compact binary systems exhibit outbursts during which their luminosity increases by orders of magnitude. The DIM correctly predicts which systems should be transient and works regardless of whether the accretor is a black hole, a neutron star, or a white dwarf. However, it has been known for some time that the outbursts of X-ray binaries, which contain neutron-star or black-hole accretors, exhibit hysteresis in the X-ray hardness-intensity diagram (HID). More recently, it has been shown that the outbursts of accreting white dwarfs also show hysteresis, but in a diagram combining optical, EUV, and X-ray fluxes.

Aims. We examine the nature of the hysteresis observed in cataclysmic variables and low-mass X-ray binaries.

Methods. We used our disc evolution code for modelling dwarf nova outbursts, and constructed the hardness intensity diagram as predicted by the disc instability model.

Results. We show explicitly that the standard DIM, modified only to account for disc truncation, can explain the hysteresis observed in accreting white dwarfs, but cannot explain that observed in X-ray binaries.

Conclusions. The spectral evidence for the existence of different accretion regimes or components (disc, corona, jets, etc.) should only be based on wavebands that are specific to the innermost parts of the discs, i.e. EUV and X-rays; this task is difficult because of interstellar absorption. The existing data, however, indicate that a hysteresis is in the EUV – X-ray domain is present in SS Cyg.
Fast coarse-grained model for RNA titration
Authors: Barroso da Silva Fernando Luís , Derreumaux Philippe , Pasquali Samuela
Published: January 2017

A new numerical scheme for RNA (ribonucleic acid) titration based on the Debye-Hückel framework for the salt description is proposed in an effort to reduce the computational costs for further applications to study protein-RNA systems. By means of different sets of Monte Carlo simulations, we demonstrated that this new scheme is able to correctly reproduce the experimental titration behavior and salt pKa shifts. In comparison with other theoretical approaches, similar or even better outcomes are achieved at much lower computational costs. The model was tested on the lead-dependent ribozyme, the branch-point helix, and the domain 5 from Azotobacter vinelandii Intron 5.
Compressibility effects on the flow past a rotating cylinder
Authors: Teymourtash A. R. , Salimipour S. E.
Published: January 2017

In this paper, laminar flow past a rotating circular cylinder placed in a compressible uniform stream is investigated via a two-dimensional numerical simulation and the compressibility effects due to the combination of the free-stream and cylinder rotation on the flow pattern such as forming, shedding, and removing of vortices and also the lift and drag coefficients are studied. The numerical simulation of the flow is based on the discretization of convective fluxes of the unsteady Navier-Stokes equations by second-order Roe’s scheme and an explicit finite volume method. Because of the importance of the time dependent parameters in the solution, the second-order time accurate is applied by a dual time stepping approach. In order to validate the operation of a computer program, some results are compared with previous experimental and numerical data. The results of this study show that the effects due to flow compressibility such as normal shock wave caused the interesting variations on the flow around the cylinder even at a free-stream with a low Mach number. At incompressible flow around the rotating cylinder, increasing the speed ratio, α (ratio of the surface speed to free-stream velocity), causes the ongoing increase in the lift coefficient, but in compressible flow for each free-stream Mach number, increasing the speed ratio results in obtaining a limited lift coefficient (a maximum mean lift coefficient). In addition, results from the compressible flow indicate that by increasing the free-stream Mach number, the maximum mean lift coefficient is decreased, while the mean drag coefficient is increased. It is also found that by increasing the Reynolds number at low Mach numbers, the maximum mean lift coefficient and critical speed ratio are decreased and the mean drag coefficient and Strouhal number are increased. However at the higher Mach numbers, these parameters become independent of the Reynolds number.
Leakage current conduction, hole injection, and time-dependent dielectric breakdown of n-4H-SiC MOS capacitors during positive bias temperature stress
Authors: Samanta Piyas , Mandal Krishna C.
Published: January 2017

The conduction mechanism(s) of gate leakage current JG through thermally grown silicon dioxide (SiO2) films on the silicon (Si) face of n-type 4H-silicon carbide (4H-SiC) has been studied in detail under positive gate bias. It was observed that at an oxide field above 5 MV/cm, the leakage current measured up to 303 °C can be explained by Fowler-Nordheim (FN) tunneling of electrons from the accumulated n-4H-SiC and Poole-Frenkel (PF) emission of trapped electrons from the localized neutral traps located at ≈2.5 eV below the SiO2 conduction band. However, the PF emission current IPF dominates the FN electron tunneling current IFN at oxide electric fields Eox between 5 and 10 MV/cm and in the temperature ranging from 31 to 303 °C. In addition, we have presented a comprehensive analysis of injection of holes and their subsequent trapping into as-grown oxide traps eventually leading to time-dependent dielectric breakdown during electron injection under positive bias temperature stress (PBTS) in n-4H-SiC metal-oxide-silicon carbide structures. Holes were generated in the heavily doped n-type polycrystalline silicon (n+-polySi) gate (anode) as well as in the oxide bulk via band-to-band ionization by the hot-electrons depending on their energy and SiO2 film thickness at Eox between 6 and 10 MV/cm (prior to the intrinsic oxide breakdown field). Transport of hot electrons emitted via both FN and PF mechanisms was taken into account. On the premise of the hole-induced oxide breakdown model, the time- and charge-to-breakdown (tBD and QBD) of 8.5 to 47 nm-thick SiO2 films on n-4H-SiC were estimated at a wide range of temperatures. tBD follows the Arrhenius law with activation energies varying inversely with initial applied constant field Eox supporting the reciprocal field (1/E) model of breakdown irrespective of SiO2 film thicknesses. We obtained an excellent margin (6.66 to 6.33 MV/cm at 31 °C and 5.11 to 4.55 MV/cm at 303 °C) of normal operating field for a 10-year projected lifetime of 8.5 to 47 nm-thick SiO2 films on n-4H-SiC under positive bias on the n+-polySi gate. Furthermore, the projected maximum operating oxide field was little higher in metal gate devices compared to n+-polySi gate devices having an identically thick thermal SiO2 films under PBTS.
Efficient algorithm for multiconfiguration pair-density functional theory with application to the heterolytic dissociation energy of ferrocene
Authors: Sand Andrew M. , Truhlar Donald G. , Gagliardi Laura
Published: January 2017

The recently developed multiconfiguration pair-density functional theory (MC-PDFT) combines multiconfiguration wave function theory with a density functional that depends on the on-top pair density of an electronic system. In an MC-PDFT calculation, there are two steps: a conventional multiconfiguration self-consistent-field (MCSCF) calculation and a post-MCSCF evaluation of the energy with an on-top density functional. In this work, we present the details of the MC-PDFT algorithm that avoids steeply scaling steps that are present in other post-self-consistent-field multireference calculations of dynamic correlation energy. We demonstrate the favorable scaling by considering systems of H2 molecules with active spaces of several different sizes. We then apply the MC-PDFT method to calculate the heterolytic dissociation enthalpy of ferrocene. We find that MC-PDFT yields results that are at least as accurate as complete active space second-order perturbation theory and are more stable with respect to basis set, but at a fraction of the cost in both time and memory.
Does the ionization potential condition employed in QTP functionals mitigate the self-interaction error?
Authors: Ranasinghe Duminda S. , Margraf Johannes T. , Jin Yifan , Bartlett Rodney J.
Published: January 2017

Though contrary to conventional wisdom, the interpretation of all occupied Kohn-Sham eigenvalues as vertical ionization potentials is justified by several formal and numerical arguments. Similarly, the performance of density functional approximations (DFAs) for fractionally charged systems has been extensively studied as a measure of one- and many-electron self-interaction errors (MSIEs). These complementary perspectives (initially recognized in ab initio dft) are shown to lead to the unifying concept that satisfying Bartlett’s IP theorem in DFA’s mitigates self-interaction errors. In this contribution, we show that the IP-optimized QTP functionals (reparameterization of CAM-B3LYP where all eigenvalues are approximately equal to vertical IPs) display reduced self-interaction errors in a variety of tests including the He2+ potential curve. Conversely, the MSIE-optimized rCAM-B3LYP functional also displays accurate orbital eigenvalues. It is shown that the CAM-QTP and rCAM-B3LYP functionals show improved dissociation limits, fundamental gaps and thermochemical accuracy compared to their parent functional CAM-B3LYP.
A donut-shape distribution of OH radicals in atmospheric pressure plasma jets
Authors: Yue Yuanfu , Wu Fan , Cheng He , Xian Yubin , Liu Dawei , Lu Xinpei , Pei Xuekai
Published: January 2017

In this work, OH radicals that have a donut-shape distribution in the room-temperature atmospheric-pressure plasma jet are investigated using the laser-induced fluorescence method. The plasma jet driven by a pulse power supply is operated under two conditions: without the ground electrode and with the ground electrode. It is found that the OH radicals distribute as a donut-shape for the first several pulses under both two conditions. With more pulses applied, the donut-shape disappears and OH radicals distribute as a solid disk. Detailed investigations show that the total OH radicals in the plasma plume are formed from two parts. One part is generated by the plasma plume outside the tube with a structure of a donut-shape. The other part is generated by the plasma inside the tube with a structure of a solid disk, which can be transported to the downstream with gas stream and leads to the disappearance of the donut-shape in the plasma plum. Moreover, when the ground electrode is applied, higher intensity of OH is obtained as well as OH donut-shape distribution is observed with dehumidified working gas. It may be due to the higher electron density and its donut-shape distribution in the effluent according to the simulations and experimental results.
Ab initio study of several static and dynamic properties of bulk liquid Ni near melting
Authors: del Rio B. G. , González L. E. , González D. J.
Published: January 2017

Several static and dynamic properties of bulk liquid Ni at a thermodynamic state near its triple point have been evaluated by ab initio molecular dynamics simulations. The calculated static structure shows very good agreement with the available experimental data, including an asymmetric second peak in the static structure factor, which underlines a marked local icosahedral short-range order in the liquid. The dynamical structure reveals propagating density fluctuations, and the calculated dynamic structure factors, S(q,ω), show a good agreement with the inelastic x-ray scattering measurements. The obtained dispersion relation closely follows that obtained from the inelastic x-ray scattering measurements; moreover we analyze the possible reasons behind its discrepancy with respect to the dispersion relation derived from the inelastic neutron scattering data. The dynamical processes behind the S(q,ω) have been analyzed by using a model with two decay channels (a fast and a slow) associated with the relaxations of the collective excitations. We have found that the transverse current spectral functions exhibit some features which, so far, had previously been shown by high pressure liquid metals only. Furthermore, the calculated S(q,ω) show, within some q-range, the appearance of transverse-like excitation modes, similar to those recently found in other liquid metals. Finally, results are also reported for several transport coefficients.
Turbulent fluctuations during pellet injection into a dipole confined plasma torus
Authors: Garnier D. T. , Mauel M. E. , Roberts T. M. , Kesner J. , Woskov P. P.
Published: January 2017

We report measurements of the turbulent evolution of the plasma density profile following the fast injection of lithium pellets into the Levitated Dipole Experiment (LDX) [Boxer et al., Nat. Phys. 6, 207 (2010)]. As the pellet passes through the plasma, it provides a significant internal particle source and allows investigation of density profile evolution, turbulent relaxation, and turbulent fluctuations. The total electron number within the dipole plasma torus increases by more than a factor of three, and the central density increases by more than a factor of five. During these large changes in density, the shape of the density profile is nearly “stationary” such that the gradient of the particle number within tubes of equal magnetic flux vanishes. In comparison to the usual case, when the particle source is neutral gas at the plasma edge, the internal source from the pellet causes the toroidal phase velocity of the fluctuations to reverse and changes the average particle flux at the plasma edge. An edge particle source creates an inward turbulent pinch, but an internal particle source increases the outward turbulent particle flux. Statistical properties of the turbulence are measured by multiple microwave interferometers and by an array of probes at the edge. The spatial structures of the largest amplitude modes have long radial and toroidal wavelengths. Estimates of the local and toroidally averaged turbulent particle flux show intermittency and a non-Gaussian probability distribution function. The measured fluctuations, both before and during pellet injection, have frequency and wavenumber dispersion consistent with theoretical expectations for interchange and entropy modes excited within a dipole plasma torus having warm electrons and cool ions.
Atomic orbital-based SOS-MP2 with tensor hypercontraction. II. Local tensor hypercontraction
Authors: Song Chenchen , Martínez Todd J.
Published: January 2017

In the first paper of the series [Paper I, C. Song and T. J. Martinez, J. Chem. Phys. 144, 174111 (2016)], we showed how tensor-hypercontracted (THC) SOS-MP2 could be accelerated by exploiting sparsity in the atomic orbitals and using graphical processing units (GPUs). This reduced the formal scaling of the SOS-MP2 energy calculation to cubic with respect to system size. The computational bottleneck then becomes the THC metric matrix inversion, which scales cubically with a large prefactor. In this work, the local THC approximation is proposed to reduce the computational cost of inverting the THC metric matrix to linear scaling with respect to molecular size. By doing so, we have removed the primary bottleneck to THC-SOS-MP2 calculations on large molecules with O(1000) atoms. The errors introduced by the local THC approximation are less than 0.6 kcal/mol for molecules with up to 200 atoms and 3300 basis functions. Together with the graphical processing unit techniques and locality-exploiting approaches introduced in previous work, the scaled opposite spin MP2 (SOS-MP2) calculations exhibit O(N2.5) scaling in practice up to 10 000 basis functions. The new algorithms make it feasible to carry out SOS-MP2 calculations on small proteins like ubiquitin (1231 atoms/10 294 atomic basis functions) on a single node in less than a day.
A broadband proton backlighting platform to probe shock propagation in low-density systems
Authors: Sio H. , Hua R. , Ping Y. , McGuffey C. , Beg F. , Heeter R. , Li C. K. , Petrasso R. D. , Collins G. W.
Published: January 2017

A proton backlighting platform has been developed for the study of strong shock propagation in low-density systems in planar geometry. Electric fields at the converging shock front in inertial confinement fusion implosions have been previously observed, demonstrating the presence of—and the need to understand—strong electric fields not modeled in standard radiation-hydrodynamic simulations. In this planar configuration, long-pulse ultraviolet lasers are used to drive a strong shock into a gas-cell target, while a short-pulse proton backlighter side-on radiographs the shock propagation. The capabilities of the platform are presented here. Future experiments will vary shock strength and gas fill, to probe shock conditions at different Z and Te.
High sensitive translational temperature measurement using characteristic curve of second harmonic signal in wavelength modulation spectroscopy
Authors: Matsui Makoto , Yamada Tohru
Published: January 2017

A high sensitive measurement system of translational temperature of plasma was developed. In this system, which is based on wavelength modulation spectroscopy, a peak value of second harmonic signal was measured as a function of modulation depth. The translational temperature was estimated by fitting the theoretically calculated curve to the measured characteristic curve. The performance of this system was examined using microwave discharge plasma. As a result of comparison with conventional laser absorption spectroscopy, both results show good agreement in the measurable region of the laser absorption spectroscopy. Next, the measurable limit of this system was investigated by decreasing the target number density. The detectable fractional absorption was as low as 3.7 × 10−5 in which condition the signal to noise ratio was the order of single digit at the averaging number of 40. This value is more than two orders of magnitude lower than that of the laser absorption spectroscopy.
Simulations of polymer brushes with charged end monomers under external electric fields
Authors: Ding Huanda , Duan Chao , Tong Chaohui
Published: January 2017

Using Langevin dynamics simulations, the response of neutral polymer brushes with charged terminal monomers to external electric fields has been investigated. The external electric field is equivalent to the field generated by the opposite surface charges on two parallel electrodes. The effects of charge valence of terminal monomers on the structure of double layers and overall charge balance near the two electrodes were examined. Using the charge density distributions obtained from simulations, the total electric field normal to the electrodes was calculated by numerically solving the Poisson equation. Under external electric fields, the total electric field across the two electrodes is highly non-uniform and in certain regions within the brush, the total electric field nearly vanishes. The probability distribution of electric force acting on one charged terminal monomer was obtained from simulations and how it affects the probability density distribution of terminal monomers was analyzed. The response of polymer brushes with charged terminal monomers to a strongly stretching external electric field was compared with that of uniformly charged polymer brushes.
Note: Suppression of kHz-frequency switching noise in digital micro-mirror devices
Authors: Hueck Klaus , Mazurenko Anton , Luick Niclas , Lompe Thomas , Moritz Henning
Published: January 2017

High resolution digital micro-mirror devices (DMDs) make it possible to produce nearly arbitrary light fields with high accuracy, reproducibility, and low optical aberrations. However, using these devices to trap and manipulate ultracold atomic systems for, e.g., quantum simulation is often complicated by the presence of kHz-frequency switching noise. Here we demonstrate a simple hardware extension that solves this problem and makes it possible to produce truly static light fields. This modification leads to a 47 fold increase in the time that we can hold ultracold 6Li atoms in a dipole potential created with the DMD. Finally, we provide reliable and user friendly APIs written in Matlab and Python to control the DMD.
PEFC catalytic properties of Pt – Ni nanoparticles prepared by a plasma-gas-condensation
Authors: Umezawa Michihisa , Ishikawa Ryoichi , Miyazaki Reona , Hihara Takehiko
Published: January 2017

Pt – Ni nanoparticles were fabricated via the gas phase method. Their performance as anode catalysts for the proton exchange membrane fuel cell was investigated as a function of Ni concentration. The microscopic configurations of the nanoparticles were rather heterogeneous; Pt-rich alloys existed in the core region of particles while a part of the surface layer was composed of the Ni-rich layer. Despite the Ni-rich layer in the shell region, the anode catalyst performance of the Pt – Ni nanoparticles was never deteriorated compared with that of the Pt ones. When the anode catalyst was composed of the Pt nanoparticles, a maximum power density of 112 mW/cm2 was obtained. However, 90% of the power density was still kept even when 40 at. % of Pt was replaced with Ni. The results suggest that a further decrease of Pt composition with maintaining its catalyst performance can be feasible by effective particle dispersing.
Telecom wavelength emitting single quantum dots coupled to InP-based photonic crystal microcavities
Authors: Kors A. , Fuchs K. , Yacob M. , Reithmaier J. P. , Benyoucef M.
Published: January 2017

Here we report on the fabrication and optical characterization of InP-based L3 photonic crystal (PhC) microcavities embedded with a medium density InAs/InP quantum dots (QDs) emitting at telecom wavelengths. The QDs are grown by solid source molecular beam epitaxy using a ripening technique. Micro-photoluminescence (μ-PL) measurements of PhC samples reveal sharp cavity modes with quality factors exceeding 8500. QDs emit highly linear-polarized light at telecom wavelengths with resolution-limited spectral linewidth below 50 μeV. Enhanced PL intensity of QDs in PhC is observed in comparison to the PL intensity of QDs in bulk semiconductors. The combination of excitation power-dependent and polarization-resolved μ-PL measurements reveal the existence of an exciton-biexciton system with a small fine-structure splitting.