bluuebunny/crossref_metadata_2025 huggingface dataset:
Earth-abundant inorganic electrocatalysts and their nanostructures for energy conversion applications
Authors: Faber Matthew S. , Jin Song
Published: August 2014

Various classes of earth-abundant inorganic electrocatalysts for energy conversion are surveyed and their recent and ongoing development is discussed.
CO2-responsive diethylaminoethyl-modified lignin nanoparticles and their application as surfactants for CO2/N2-switchable Pickering emulsions
Authors: Qian Yong , Zhang Qi , Qiu Xueqing , Zhu Shiping
Published: August 2014

CO2/N2-triggered water-dispersible/collectable lignin-g-DEAEMA nanoparticles were successfully synthesized and were used to prepare emulsified/demulsified switchable Pickering emulsions by gas processing under nearly neutral conditions.
Enhanced propionic acid production from whey lactose with immobilized Propionibacterium acidipropionici and the role of trehalose synthesis in acid tolerance
Authors: Jiang Ling , Cui Huaiyan , Zhu Liying , Hu Yi , Xu Xian , Li Shuang , Huang He
Published: August 2014

High propionic acid production could be achieved with an enhanced trehalose synthesis mutant immobilized on PEI-Poraver in FBB fed-batch fermentation.
Hot carriers in epitaxial graphene sheets with and without hydrogen intercalation: role of substrate coupling
Authors: Liu Fan-Hung , Lo Shun-Tsung , Chuang Chiashain , Woo Tak-Pong , Lee Hsin-Yen , Liu Chieh-Wen , Liu Chieh-I , Huang Lung-I , Liu Cheng-Hua , Yang Yanfei , Chang Chih-Yuan S. , Li Lain-Jong , Mende Patrick C. , Feenstra Randall M. , Elmquist Randolph E. , Liang Chi-Te
Published: August 2014

Reduced energy relaxation with hydrogen intercalation.
A stretchable strain sensor based on a metal nanoparticle thin film for human motion detection
Authors: Lee Jaehwan , Kim Sanghyeok , Lee Jinjae , Yang Daejong , Park Byong Chon , Ryu Seunghwa , Park Inkyu
Published: August 2014

Wearable strain sensors for human motion detection are being highlighted in various fields such as medical, entertainment and sports industry.
Exploitable length correlations in peptide nanofibres
Authors: De Santis Emiliana , Faruqui Nilofar , Noble James E. , Ryadnov Maxim G.
Published: August 2014

A model sequence template encodes different fibre lengths that correlate with cell proliferation as a function of peptide length.
Thiomyristoyl peptides as cell-permeable Sirt6 inhibitors
Authors: He Bin , Hu Jing , Zhang Xiaoyu , Lin Hening
Published: August 2014

Potent mechanism-based Sirt6 inhibitors.
Pyrazole–oxadiazole conjugates: synthesis, antiproliferative activity and inhibition of tubulin polymerization
Authors: Kamal Ahmed , Shaik Anver Basha , Polepalli Sowjanya , Santosh Reddy Vangala , Bharath Kumar G. , Gupta Soma , Rama Krishna K. V. S. , Nagabhushana Ananthamurthy , Mishra Rakesh K. , Jain Nishant
Published: August 2014

A library of pyrazole–oxadiazole conjugates were synthesized and investigated for their antiproliferative activity in human cancer cell lines.
Selective transamidation of 3-oxo-N-acyl homoserine lactones by hydrazine derivatives
Authors: Bertucci Michael A. , Lee Stephen J. , Gagné Michel R.
Published: August 2014

Hydrazine derivatives are employed for selective amide cleavage of 3-oxo-N-acyl homoserine lactones under physiologically relevant conditions.
AcOH-mediated dichloroimination of indoles using chloramine-B: a facile access to 2,3-functionalized indolines
Authors: Liu Xiaozu , Hu Qinghong , Yuan Zeli , Liu Peijun
Published: August 2014

A mild method for the efficient synthesis of 3,3-dichloro-2-sulfonyliminoindolines via AcOH-mediated dichloroimination of indoles using chloramine-B is described.
Asymmetric Michael addition of ketones to nitroolefins: pyrrolidinyl-oxazole-carboxamides as new efficient organocatalysts
Authors: Kamal Ahmed , Sathish Manda , Srinivasulu Vunnam , Chetna Jadala , Chandra Shekar Kunta , Nekkanti Shalini , Tangella Yellaiah , Shankaraiah Nagula
Published: August 2014

New pyrrolidinyl-oxazole-carboxamides were synthesized and utilized as efficient organocatalysts for asymmetric Michael addition reaction. In addition, computational mechanistic studies were performed.
1,3-Halogen migration as an entry to aryl coppers from an unintuitive starting material
Authors: Van Hoveln R. J. , Schmid S. C. , Schomaker J. M.
Published: August 2014

Cu-catalyzed 1,3-halogen migration provides a unique way to generate reactive aryl copper species for arene functionalizations.
Recent developments in transition metal-catalysed spiroketalisation
Authors: Quach Rachelle , F. Chorley Daniel , Brimble Margaret A.
Published: August 2014

This perspective updates recent developments (since 2012) in the synthesis of spiroketals using transition metal catalysis.
Ultra bright red AIE dots for cytoplasm and nuclear imaging
Authors: Wang Zilong , Yan Lulin , Zhang Lei , Chen Yujue , Li Hui , Zhang Jibo , Zhang Yan , Li Xing , Xu Bin , Fu Xueqi , Sun Zaicheng , Tian Wenjing
Published: August 2014

An aggregation-induced emission (AIE) molecule, TPA-AN-TPM, with near-infrared emission was synthesized by coating a disc-like red emission fluorophore with a propeller-shaped AIE fluorophore.
Interface chemistry engineering in electrode systems for electrochemical energy storage
Authors: Yu Lei , Qian Zhongyu , Shi Nannan , Liu Qi , Wang Jun , Jing Xiaoyan
Published: August 2014

In this review, we introduce two powerful strategies for well-controlled interface. Interface chemistry engineering in electrode systems for electrochemical energy storage needs to integrate individual materials components to interface design and optimization.
Factors controlling the photoresponse of copper(i) diimine dyes containing hole-transporting dendrons in dye-sensitized solar cells: substituent and solvent effects
Authors: Brauchli Sven Y. , Bozic-Weber Biljana , Constable Edwin C. , Hostettler Nik , Housecroft Catherine E. , Zampese Jennifer A.
Published: August 2014

A detailed study of how two factors (substituents on ancillary ligands and solvents during dye assembly) affect performances of copper(i) diimine dyes in DSCs with phosphonic acid anchoring groups is presented.
Low-temperature sol–gel synthesis of crystalline materials
Authors: Vinogradov Alexandr V. , Vinogradov Vladimir V.
Published: August 2014

Sol–gel chemistry has opened a new era of modern materials science by enabling the production of ceramic materials at near-room temperature.
Computational study on redox-switchable second-order nonlinear optical properties of ferrocene-tetrathiafulvalene hybrid
Authors: Liu Chun-Guang , Gao Ming-Li , Wu Zhi-Jian
Published: August 2014

Redox-switchable second-order nonlinear optical (NLO) responses of a series of ferrocene-tetrathiafulvalene (Fc–TTF) hybrids have been studied based on density functional theory calculations.
Use of electrochemical measurements to investigate the porosity of ultra-thin Al2O3 films prepared by atomic layer deposition
Authors: Chai Zhimin , Li Jing , Lu Xinchun , He Dannong
Published: August 2014

The porosity of ultra-thin alumina (Al2O3) films was determined by electrochemical measurements.
Highly reversible lithium storage in a 3D macroporous Ge@C composite
Authors: Cheng Jianxiu , Wang Jiaqing , Li Weihan , Liu Xiaowu , Yu Yan
Published: August 2014

A porous Ge@C composite was synthesized by magnesiothermic reduction reaction of GeO2, Mg powder and glucose followed by an etching process with HCl solution.
Mesoporous graphite nanoflakes via ionothermal carbonization of fructose and their use in dye removal
Authors: Xie Zai-Lai , Huang Xing , Titirici Maria-Magdalena , Taubert Andreas
Published: August 2014

The ionothermal synthesis of oligo-layer graphene-type nanoflakes from fructose in the iron-containing ionic liquid 1-butyl-3-methylimidazolium tetrachloridoferrate (III), [Bmim][FeCl4] serving as solvent, catalyst, and template for product formation is presented.
Theoretical prediction of low-density nanoporous frameworks of zinc sulfide based on ZnnSn(n = 12, 16) nanocaged clusters
Authors: Yong Yongliang , Li Xiaohong , Hao Xiping , Cao Jingxiao , Li Tongwei
Published: August 2014

Low-density ZnS framework materials with novel structures and properties based on highly stable ZnnSn(n= 12, 16) clusters are designed and investigated.
2,3-Diaryl-substituted indole based COX-2 inhibitors as leads for imaging tracer development
Authors: Laube Markus , Tondera Christoph , Sharma Sai Kiran , Bechmann Nicole , Pietzsch Franz-Jacob , Pigorsch Arne , Köckerling Martin , Wuest Frank , Pietzsch Jens , Kniess Torsten
Published: August 2014

A series of 2,3-diaryl-substituted indoles containing a fluorine or methoxy group was synthesized via Fischer indole synthesis, McMurry cyclization, or Bischler–Möhlau reaction to identify potential leads for PET radiotracer development.
Facile synthesis of single-crystalline hollow α-Fe2O3 nanospheres with gas sensing properties
Authors: Wang Pei-Pei , Zou Xiaoxin , Feng Liang-Liang , Zhao Jun , Jin Pan-Pan , Xuan Rui-Fei , Tian Ye , Li Guo-Dong , Zou Yong-Cun
Published: August 2014

High-quality single-crystalline hollow α-Fe2O3 nanospheres were prepared, using ZnS–CHA nanohybrid as additive with gas sensing property.
Catalytic hydrogen evolution from hydrolytic oxidation of organosilanes with silver nitrate catalyst
Authors: Teo Alan Kay Liang , Fan Wai Yip
Published: August 2014

Highly efficient silver nitrate mediated hydrogen generation from the hydrolysis of organosilanes.
Synthesis of 3-aryl-2-aminoquinolines: palladium-catalyzed cascade reactions of gem-dibromovinylanilines with tert-butyl isocyanide and arylboronic acids
Authors: Hu Langxi , Gui Weijun , Liu Zichen , Jiang Baishan
Published: August 2014

A three-component cascade reaction involving gem-dibromovinylanilines, tert-butyl isocyanide and arylboronic acids for the efficient synthesis of 3-aryl-2-aminoquinolines has been developed.
Enhanced photovoltaic performance of silver@titania plasmonic photoanode in dye-sensitized solar cells
Authors: Lim Su Pei , Pandikumar Alagarsamy , Huang Nay Ming , Lim Hong Ngee
Published: August 2014

Ag@TiO2 plasmonic photoanode modified dye-sensitized solar cells showed enhanced photovoltaic performance due to surface plasmon resonance effect.
Self-assembled triphenylamine derivative for trace detection of picric acid
Authors: Wenfeng Li , Hengchang Ma , Ziqiang Lei
Published: August 2014

Triphenylamine derivative chemosensors in contact mode and vapor phase exhibit efficient quenching behaviors for detection of PA at attogram level.
Silica/CdTe/silica fluorescent composite nanoparticles via electrostatic assembly as a pH ratiometer
Authors: Ran Zhipeng , Yang Wuli
Published: August 2014

Sandwich-like colloidal silica/CdTe quantum dots/silica nanoparticles are fabricated by efficient electrostatic assembly. They show remarkable stabilities and bright fluorescence, affording the application of pH ratiometric nanosensor.
Hydrothermal synthesis of single-crystalline mesoporous beta zeolite assisted by N-methyl-2-pyrrolidone
Authors: Liu Lijia , Wang Hongbin , Wang Runwei , Zeng Shangjing , Ni Ling , Zhang Daliang , Zhu Liangkui , zou Houbing , Qiu Shilun , Zhang Zongtao
Published: August 2014

A novel synthesis of single-crystalline mesoporous beta zeolite with high catalytic activities by addition of low-cost N-methyl-2-pyrrolidone (NMP) into a conventional TEAOH-based zeolite synthesis system.
Facile synthesis of nanostructured carbon nanotube/iron oxide hybrids for lithium-ion battery anodes
Authors: Yu Seung-Ho , Guo Xiaohui , Ling Daishun , Chung Dong Young , Jin Aihua , Shokouhimehr Mohammadreza , Hyeon Taeghwan , Sung Yung-Eun
Published: August 2014

Nanostructured carbon nanotubes/iron oxide hybrids (CNIOHs) were synthesized by a scalable Bake-Break-Mix process which involves three simple steps.
Synthesis of a borylated boron–dibenzopyrromethene dye enabling the visual detection of H2O2 vapor
Authors: Matsumoto Asaki , Nishiyabu Ryuhei , Kubo Yuji
Published: August 2014

A boron–dibenzopyrromethene dye with a pinacolboryl group has been newly synthesized for the use as a reaction-based chemosensor. A TLC plate coated by the dye enables us to detect H2O2 vapor visually.
Ag nanoparticles supported on N-doped graphene hybrids for catalytic reduction of 4-nitrophenol
Authors: Tian Ye , Cao Yan-yan , Pang Fu , Chen Gui-qiang , Zhang Xiao
Published: August 2014

Ag/N–RGO showed a higher catalytic ability than Ag NPs or N–RGO alone, and Ag/RGO, which was due to the synergetic effects between Ag NPs and N–RGO.
Synthetic approach to novel azido esters and their utility as energetic plasticizers
Authors: Kumari Dimple , S. G. Anjitha , Pant Chandra Shekhar , Patil Mahendra , Singh Haridwar , Banerjee Shaibal
Published: August 2014

A modular approach towards a series of novel di azido, tetra azido and hexa azido esters is introduced here.
Nanoindentation creep behavior of enamel biological nanocomposites
Authors: Zhang Jing , Wang Chunbao , Yang Fan , Du Chang
Published: August 2014

Organic matrix and water are essential factors for enamel biological nanocomposite to resist external force as revealed by nanoindentation creep test.
Formulation of novel screen-printable dielectric ink for fully-printed TIPs-pentacene OFETs
Authors: Hou Xiaoya , Xia Yijie , Ng Siu Choon , Zhang Jie , Chang Joseph Sylvester
Published: August 2014

Polymer nanocomposite dielectric inks based on P(VDF-TrFE)/PMMA/BaTiO3/silica were formulated for screen printing.
Molecular weight-modulated electrospun poly(ε-caprolactone) membranes for postoperative adhesion prevention
Authors: Zhang Jin , Liu He , Xu Huan , Ding Jian-Xun , Zhuang Xiu-Li , Chen Xue-Si , Chang Fei , Xu Jia-Zhuang , Li Zhong-Ming
Published: August 2014

Electrospun PCL membranes with various molecular weights behave distinctively for the prevention of surgery induced-adhesions, which finally helped acquire well-suited candidates for anti-adhesion biomaterial films.
Extraction of alpha-fetoprotein (AFP) with magnetic albuminoid-imprinted poly(ethylene-co-vinyl alcohol) nanoparticles from human hepatocellular carcinoma HepG2 cellular culture medium
Authors: Lee Mei-Hwa , Ahluwalia Arti , Hsu Ke-Ming , Chin Wei-Ti , Lin Hung-Yin
Published: August 2014

The selective adsorption of alpha-fetoprotein using albuminoid MMIP nanoparticles from the human hepatocellular carcinoma HepG2 cellular culture medium.
Relativistic effects on the 125Te and 33S NMR chemical shifts of various tellurium and sulfur species, together with 77Se of selenium congeners, in the framework of a zeroth-order regular approximation: applicability to tellurium compounds
Authors: Hayashi Satoko , Matsuiwa Kohei , Nakanishi Waro
Published: August 2014

The relativistic effects on σ(Te), σ(Se), and σ(S) were evaluated separately by scalar and spin–orbit terms for various species containing Te, Se, and S nuclei. The applicability of σt(Te)Rlt-so to analyze δ(Te)obsd and the trend in the nuclei are discussed.
Approach to tune short-circuit current and open-circuit voltage of dye-sensitized solar cells: π-linker modification and photoanode selection
Authors: Zhu Shengbo , An Zhongwei , Chen Xinbing , Chen Pei , Liu Qianfeng
Published: August 2014

The modification of the π-linker of cyclic thiourea functionalized dyes has a significant effect on the short-circuit current density and open-circuit voltage of dye-sensitized solar cells.
Peptide targeting of fluorescein-based sensors to discrete intracellular locales
Authors: Radford Robert J. , Chyan Wen , Lippard Stephen J.
Published: August 2014

Fluorescein-labeled peptides are often sequestered within acidic vesicles, diminishing their applicability for live cell imaging. Installing reactive acetyl groups onto the sensing moiety of a labeled peptide facilitates endosomal escape and allows for peptide-based targeting of fluorescent sensors to discrete intracellular locales.
Thermo-sensitive discotic colloidal liquid crystals
Authors: Wang Xuezhen , Zhao Di , Diaz Agustin , Nava Medina Ilse B. , Wang Huiliang , Cheng Zhengdong
Published: August 2014

The thickness of the ZrP–PNIPAM platelets can be adjusted by changing the temperature, and it is revealed that soft disks self-assemble into nematic liquid crystals in a wider thickness-over-diameter ratio than do hard disks.
Quantitative mechanical analysis of thin compressible polymer monolayers on oxide surfaces
Authors: Huang Qian , Yoon Ilsun , Villanueva Josh , Kim Kanguk , Sirbuly Donald J.
Published: August 2014

The nanomechanical properties of thin, compressible polyethylene glycol monolayers deposited on oxide films and nanostructures are thoroughly investigated in a liquid environment using atomic force microscopy.
Adsorption of “soft” spherical particles onto sinusoidally-corrugated substrates
Authors: Schoch Phillip K. , Genzer Jan
Published: August 2014

We utilize a Monte Carlo simulation scheme based on the bond fluctuation model to simulate settlement of “soft” adhesive particles onto sinusoidally-corrugated substrates.
Oxygen vacancies in self-assemblies of ceria nanoparticles
Authors: Sk Mahasin Alam , Kozlov Sergey M. , Lim Kok Hwa , Migani Annapaola , Neyman Konstantin M.
Published: August 2014

The corner Ce atoms are essential for a noticeable reduction of the oxygen vacancy formation energy,Ef(Ovac), in nanostructured CeO2.
Molecular simulation and experimental study on propylene dehumidification through a PVA–PAA blend membrane
Authors: Dong Xiuqin , Liu Qiao , Cui Li , Yu Yingzhe , Zhang Minhua
Published: August 2014

PVA–PAA blend membranes exhibited better separation performance for propylene dehumidification and they were analyzed by simulation and experiments.
Low pressure induced porous nanorods of ceria with high reducibility and large oxygen storage capacity: synthesis and catalytic applications
Authors: Li Jing , Zhang Zhiyun , Tian Zhimin , Zhou Xuemei , Zheng Zhiping , Ma Yuanyuan , Qu Yongquan
Published: August 2014

A new form of nanoceria, porous nanorods of ceria (PN-CeO2), was prepared by a two-step hydrothermal synthesis. PN-CeO2has been found to display enhanced reducibility and capacity for oxygen storage.
Enzymatic degradation of oxidized and reduced graphene nanoribbons by lignin peroxidase
Authors: Lalwani Gaurav , Xing Weiliang , Sitharaman Balaji
Published: August 2014

We report structural degradation of oxidized and reduced graphene nanoribbons by the enzyme lignin peroxidase.
Experimental evaluations of RSS threshold‐based optimised DV‐HOP localisation for wireless ad‐hoc networks
Authors: Maung N.A.M. , Kawai M.
Published: August 2014

DV‐HOP is a well‐known connectivity‐based range‐free scheme which offers a cost‐effective localisation solution for resource‐constrained wireless ad‐hoc and sensor networks. However, it generates a prominent amount of error with small‐scale networks due to its multi‐hop nature. To minimise the error and to make it applicable to both small‐ and large‐scale networks, it is proposed to configure the connectivity of the network using available received signal strength (RSS) measurements and a predefined RSS threshold. An approximate formula for the optimal RSS threshold value that shows the minimum amount of error for a particular network to be localised is derived as a function of the total number of nodes and the network size. Experimental results confirm that utilising the proposed RSS threshold‐based connectivity configuration significantly improves the localisation accuracy of DV‐HOP in a practical environment without any extra hardware.
Space‐memory‐memory Clos‐network switches with in‐sequence service
Authors: Zhang Maosen , Qiu Zhiliang , Gao Ya
Published: August 2014

Clos‐network switches have attracted a lot of attention because of their modularity and scalability. However, out‐of‐sequence problems weigh heavily against the application of buffered Clos‐network switches. A space‐memory‐memory (SMM) Clos‐network switch is proposed in this study which is able to provide in‐sequence service. There are two features in the proposed switch which are different from the previously proposed schemes. First, two‐stage load‐balanced Birkhoff‐von Neumann (LB‐BvN) switches are adopted for each second‐stage module. Second, no inter‐stage matching is needed. The key idea to provide in‐order cell delivery in the proposed SMM Clos‐network switch is that cells belonging to the same flow will experience the identical delay when passing through the LB‐BvN switches at the second stage, and arrive at their destined third‐stage module in order. Each switching module operates independently, which makes the proposed SMM Clos‐network switch practical to implement in hardware. Simulations show that the proposed switch can achieve high performance under both Bernoulli and Bursty arrival traffic.
Evaluation of generalised relay selection in the presence of feedback delay for multi‐hop relaying
Authors: Long Min , Shi Rui , Chen Yunfei
Published: August 2014

In this work, the impact of outdated channel state information because of feedback delay is evaluated for the performances of several generalised relay selection schemes. Multi‐hop amplify‐and‐forward relaying is considered over Rayleigh fading channels. Numerical results show that different relay selection schemes suffer from different performance degradations when the hop index increases. Interestingly, for generalised relay selection, numerical results also show that selecting more relays does not necessarily lead to better power outage probability and bit error rate performances. These observations provide useful guidance on relaying system designs.
Stability of sampled‐data, delayed haptic interaction under passive or active operator
Authors: Miandashti Noushin , Tavakoli Mahdi
Published: August 2014

This study studies the absolute stability of a sampled‐data, m ‐user haptic virtual environment (HVE) system based on the discrete‐time circle criterion. Depending on the task being performed by an operator, the passivity of the operator is influenced. The authors provide a framework for the system stability analysis, in which the operator is allowed to exhibit passive or active behaviour. In this study, the well‐known Colgate's stability condition for a 1‐user haptic system with a passive operator is reproduced and then extended to the m ‐user case while allowing each or all of the operators to behave passively or actively. Another extension to Colgate's condition comes by allowing communication delays to exist in the system. Simulations and experiments confirm the validity of the proposed conditions for stability of sampled‐data, delayed m ‐user HVE systems.
Reduced sensor configuration of brushless DC motor drive using a power factor correction‐based modified‐zeta converter
Authors: Bist Vashist , Singh Bhim
Published: August 2014

This study deals with the design and development of a power factor (PF) correction‐based modified‐zeta converter fed brushless DC (BLDC) motor drive. A single‐phase supply followed by a diode bridge rectifier and a modified‐zeta converter operating in discontinuous inductor current mode (DICM) is used to feed a voltage source inverter (VSI) driving a BLDC motor. The modified‐zeta converter operating in DICM acts as an inherent PF pre‐regulator. A single‐voltage sensor is used for the DC‐link voltage control, which is used to control the speed of the BLDC motor. This facilitates the operation of VSI in fundamental frequency switching for reducing the switching losses in VSI. The proposed BLDC motor drive is designed and its performance is simulated in MATLAB/Simulink environment for achieving an improved power quality at AC mains for wide range of speed control. The obtained power quality indices are under the recommended limits of international power quality standard IEC 61000‐3‐2. Finally, the performance of the proposed drive is validated with test results obtained on a developed prototype of the proposed BLDC motor drive.
Control scheme for cascaded H‐bridge converter‐based distribution network static compensator
Authors: Marzoughi Alinaghi , Neyshabouri Yousef , Imaneini Hossein
Published: August 2014

In this study, a new control scheme is proposed for cascaded H‐bridge (CHB)‐based static compensator (STATCOM). The new indirect current control method does not require any current sensors, so the total system has enhanced reliability. Using the proposed control approach, dc‐link voltages across dc‐link capacitors are regulated to the reference value, even if the H‐bridge cells dissipate different amounts of losses. However, regardless of the active power distribution, the reactive power is equally shared between the cells. The proposed scheme is investigated on distribution network STATCOM, but is not restricted to that and can be applied to STATCOMs at any voltage and power level. Multicarrier phase‐shifted sinusoidal pulse‐width modulation is used for modulation purpose, since it is naturally the best option for CHB converter. In this way, low‐order harmonics are eliminated from the line side current and the current THD is below 5%, which satisfies IEEE‐519 standard. To verify the feasibility of the control strategy, simulations as well as experimental implementations are carried out on a CHB converter having three cells in each phase.
Non‐isolated multi‐input–single‐output DC/DC converter for photovoltaic power generation systems
Authors: Banaei Mohammad Reza , Ardi Hossein , Alizadeh Rana , Farakhor Amir
Published: August 2014

A new multi‐input non‐isolated DC/DC converter with high‐voltage transfer gain is proposed in this study. The presented converter consists of the conventional buck–boost and boost converters. All the stages except the last stage are buck–boost converters. The last stage is the conventional boost converter. The proposed multi‐input high‐voltage gain converter benefits from various advantages such as reduced semiconductor current stress, no limitation for switching duty cycle and wide control range of different input powers. The presented converter can even operate when one or some power input fail to provide energy to the load. The steady‐state operation and dynamic modelling of the suggested converter are analysed thoroughly. Experimental results are also provided to verify the feasibility of the presented converter.
Finite control set predictive control based on Lyapunov function for three‐phase voltage source inverters
Authors: Kwak Sangshin , Yoo Sung‐Jin , Park Juncheol
Published: August 2014

A Lyapunov‐function‐based technique for finite control set predictive control is proposed to control the load currents of three‐phase voltage source inverters (VSIs). The developed technique, based on a discrete‐time model of a VSI, determines a control law using the Lyapunov function. Based on the Lyapunov stability analysis considering inevitable quantisation errors between the proposed control law and control actions selected from the inherent finite control set of the VSI, all signals of the closed‐loop dynamics are uniformly ultimately bounded and the current control errors converge to a neighbourhood of the origin. In addition to rendering the finite control set predictive control system globally stable, the proposed Lyapunov‐function‐based finite control set predictive control reduces the amount of calculations required to predict a future variable by half compared with the conventional finite control set predictive control, resulting in lower actuation time delay. Experimental results with three‐phase VSIs are presented to validate the proposed Lyapunov‐function‐based control method.
Micro- and nanodomain imaging in uniaxial ferroelectrics: Joint application of optical, confocal Raman, and piezoelectric force microscopy
Authors: Ya. Shur V. , Zelenovskiy P. S.
Published: August 2014

The application of the most effective methods of the domain visualization in model uniaxial ferroelectrics of lithium niobate (LN) and lithium tantalate (LT) family, and relaxor strontium-barium niobate (SBN) have been reviewed in this paper. We have demonstrated the synergetic effect of joint usage of optical, confocal Raman, and piezoelectric force microscopies which provide extracting of the unique information about formation of the micro- and nanodomain structures. The methods have been applied for investigation of various types of domain structures with increasing complexity: (1) periodical domain structure in LN and LT, (2) nanodomain structures in LN, LT, and SBN, (3) nanodomain structures in LN with modified surface layer, (4) dendrite domain structure in LN. The self-assembled appearance of quasi-regular nanodomain structures in highly non-equilibrium switching conditions has been considered.
Characterizing absolute piezoelectric microelectromechanical system displacement using an atomic force microscope
Authors: Evans J. , Chapman S.
Published: August 2014

Piezoresponse Force Microscopy (PFM) is a popular tool for the study of ferroelectric and piezoelectric materials at the nanometer level. Progress in the development of piezoelectric MEMS fabrication is highlighting the need to characterize absolute displacement at the nanometer and Ångstrom scales, something Atomic Force Microscopy (AFM) might do but PFM cannot. Absolute displacement is measured by executing a polarization measurement of the ferroelectric or piezoelectric capacitor in question while monitoring the absolute vertical position of the sample surface with a stationary AFM cantilever. Two issues dominate the execution and precision of such a measurement: (1) the small amplitude of the electrical signal from the AFM at the Ångstrom level and (2) calibration of the AFM. The authors have developed a calibration routine and test technique for mitigating the two issues, making it possible to use an atomic force microscope to measure both the movement of a capacitor surface as well as the motion of a micro-machine structure actuated by that capacitor. The theory, procedures, pitfalls, and results of using an AFM for absolute piezoelectric measurement are provided.
Femtosecond laser comb based subterahertz synthesizer
Authors: Makarov D. S. , Tretyakov M. Yu. , Shkaev A. P. , Kiselev A. M. , Stepanov A. N. , Parshin V. V.
Published: August 2014

Functioning layout of a frequency comb-based subterahertz synthesizer is demonstrated. A primary subterahertz oscillator was phase-locked against the Ti:Sapphire femtosecond laser frequency comb down-converted to the subterahertz range by the semiconductor mixer. Synthesizer operation is demonstrated through Fabri-Perot resonator response curve recording experiment. Spectral purity of the synthesizer was estimated. The advantage of the comb-based synthesizer over the synthesizer based on the Agilent E8257D device was shown.
Revisiting the interpretation of biased luminescence: Effects on Cu(In,Ga)Se2 photovoltaic heterostructures
Authors: Lombez L. , Soro M. , Delamarre A. , Naghavi N. , Barreau N. , Lincot D. , Guillemoles J.-F.
Published: August 2014

We analyzed the luminescence signal under electrical bias (Lum-V) for several Cu(In,Ga)Se2 solar cells having different absorber growth processes and different buffer layers such as CdS and ZnS. A numerical model is developed taking into account optical and electrical properties of the complete heterostructures. It appears that the absorber-buffer interface has a crucial role in explaining the different behaviors. Our interpretation is based on the quasi Fermi level splitting (QFL) linked to both the applied voltage and the luminescence intensity. Lum-V experiments and its dependence on illumination intensity are discussed and could be used to access transport properties when looking at the depth variation of the QFL and offer a classification of the possible cases.
First-principles high-pressure unreacted equation of state and heat of formation of crystal 2,6-diamino-3, 5-dinitropyrazine-1-oxide (LLM-105)
Authors: Manaa M. Riad , Kuo I-Feng W. , Fried Laurence E.
Published: August 2014

We report dispersion-corrected density functional theoretical calculations of the unreacted equation of state (EOS) of crystal 2,6-diamino-3, 5-dinitropyrazine-1-oxide (LLM-105) under hydrostatic compression of up to 45 GPa. Convergence tests for k-points sampling in the Brillouin zone show that a 3 × 1 × 2 mesh is required to reproduce the X-ray crystal structure at ambient conditions, and we confirm our finding with a separate supercell calculation. Our high-pressure EOS yields a bulk modulus of 19.2 GPa, and indicates a tendency towards anisotropic compression along the b lattice vector due to molecular orientations within the lattice. We find that the electronic energy band gap decreases from a semiconductor type of 1.3 eV at 0 GPa to quasi-metallic type of 0.6 eV at 45 GPa. The extensive intermolecular hydrogen bonds involving the oxide (–NO) and dioxide (–NO2) interactions with the amine (–NH2) group showed enhanced interactions with increasing pressure that should be discernible in the mid IR spectral region. We do not find evidence for structural phase transitions or chemically induced transformations within the pressure range of our study. The gas phase heat of formation is calculated at the G4 level of theory to be 22.48 kcal/mol, while we obtain 25.92 kcal/mol using the ccCA-PS3 method. Density functional theory calculations of the crystal and the gas phases provided an estimate for the heat of sublimation of 32.4 kcal/mol. We thus determine the room-temperature solid heat of formation of LLM-105 to be −9.9 or −6.5 kcal/mol based on the G4 or ccCA-PS3 methods, respectively.
Interaction of a vortex ring with a natural convective layer
Authors: Palacios-Morales C. , Gelderblom G. , Solorio F. , Salinas-Vázquez M. , Zenit R.
Published: August 2014

We study the dynamics of the interaction of a vortex ring with a shear flow, generated by a natural convective layer. Laminar vortex rings were generated in water with a piston-cylinder arrangement. To generate the shear flow, a vertical wall was heated by a thermal bath held at constant temperature to produce a laminar and stable thermal boundary layer with a Grashof number of O(108). Measurements of the two-dimensional velocity field were obtained with a time resolved particle image velocimetry technique. Additionally, a 3D numerical model was used to simulate the experimental conditions. We mainly conducted experiments for the piston stroke L/D0 = 1 and Re of O(1000). The velocity ratio r = Uvi/Ush (where Uvi is the initial vortex velocity and Ush is the maximum velocity of the shear layer) was in the range 2.2 ⩽ r ⩽ 3.6. The results show that as the vortex approaches the shear layer, the ring expands and stretches mainly in the vertical direction and tilts slightly forming an angle between the wall and the ring plane which increases to about 3°. The rate of reduction of circulation is slower at the lower section of the vortex ring indicating that the momentum transport is more significant in this region. Moreover, the vortex circulation at the lower section increases to about 20% compared to the isothermal case. An analysis of the different mechanisms leading to this ring-shear layer interaction is presented and comparisons with reported data are discussed.
Electronic and magnetic properties of armchair MoS2 nanoribbons under both external strain and electric field, studied by first principles calculations
Authors: Hu Ting , Zhou Jian , Dong Jinming , Kawazoe Yoshiyuki
Published: August 2014

The electronic and magnetic properties of armchair edge MoS2 nanoribbons (MoS2-ANRs) underboth the external strain and transverse electric field (Et) have been systematically investigated by using the first-principles calculations. It is found that: (1) If no electric field is applied, an interesting structural phase transition would appear under a large tensile strain, leading to a new phase MoS2-A'NR, and inducing a big jump peak of the band gap in the transition region. But, the band gap response to compressive strains is much different from that to tensile strain, showing no the structural phase transition. (2) Under the small tensile strains (<10%), the combined Et and tensile strain give rise to a positive superposition (resonant) effect on the band gap reduction at low Et (<3 V/nm), and oppositely a negative superposition (antiresonant) one at high Et (>4 V/nm). On the other hand, the external compressive strains have always presented the resonant effect on the band gap reduction, induced by the electric field. (3) After the structural phase transition, an external large tensile strain could greatly reduce the critical field Etc causing the band gap closure, and make the system become a ferromagnetic (FM) metal at a relative low Et (e.g., <4 V/nm), which is very helpful for its promising applications in nano-mechanical spintronics devices. (4) At high Et (>10 V/nm), the magnetic moments of both the MoS2-ANR and MoS2-A'NR in their FM states could be enhanced greatly by a tensile strain. Our numerical results of effectively tuning physical properties of MoS2-ANRs by combined external strain and electric field may open their new potential applications in nanoelectronics and spintronics.
Free-boundary models of a meltwater conduit
Authors: Dallaston Michael C. , Hewitt Ian J.
Published: August 2014

We analyse the cross-sectional evolution of an englacial meltwater conduit that contracts due to inward creep of the surrounding ice and expands due to melting. Making use of theoretical methods from free-boundary problems in Stokes flow and Hele–Shaw squeeze flow we construct an exact solution to the coupled problem of external viscous creep and internal heating, in which we adopt a Newtonian approximation for ice flow and an idealized uniform heat source in the conduit. This problem provides an interesting variant on standard free-boundary problems, coupling different internal and external problems through the kinematic condition at the interface. The boundary in the exact solution takes the form of an ellipse that may contract or expand (depending on the magnitudes of effective pressure and heating rate) around fixed focal points. Linear stability analysis reveals that without the melting this solution is unstable to perturbations in the shape. Melting can stabilize the interface unless the aspect ratio is too small; in that case, instabilities grow largest at the thin ends of the ellipse. The predictions are corroborated with numerical solutions using boundary integral techniques. Finally, a number of extensions to the idealized model are considered, showing that a contracting circular conduit is unstable to all modes of perturbation if melting occurs at a uniform rate around the boundary, or if the ice is modelled as a shear-thinning fluid.
Density distribution in two-dimensional weakly compressible turbulence
Authors: Terakado Daiki , Hattori Yuji
Published: August 2014

The statistical properties of the two-dimensional weakly compressible decaying turbulence are studied by direct numerical simulation. Particular attention is paid on the density distributions and their properties. It turned out that they depend strongly on the initial conditions of entropy and compressible component of the flow. In the non-uniform entropy case with an incompressible flow sheet structures, which are peaks and troughs in the density field, appear because of the filamentation of entropy. They do not appear in the uniform entropy case, however. As a result the power law of the density spectrum is different between the two cases. In the non-uniform entropy case the density spectrum scales as k−1, where k is the wavenumber, since density behaves as a passive scalar. In the uniform entropy case, on the other hand, it scales as k−5 as predicted for pressure in the two-dimensional incompressible turbulence since density fluctuation is approximately proportional to pressure fluctuation. When the initial velocity field has a compressible component, weak shocklets appear even for the low Mach number M0 = 0.1. The density spectrum scales as k−3 regardless of the initial conditions of entropy.
Transparent conductor-Si pillars heterojunction photodetector
Authors: Yun Ju-Hyung , Kim Joondong , Park Yun Chang
Published: August 2014

We report a high-performing heterojunction photodetector by enhanced surface effects. Periodically, patterned Si substrates were used to enlarge the photo-reactive regions and yield proportionally improved photo-responses. An optically transparent indium-tin-oxide (ITO) was deposited on a Si substrate and spontaneously formed an ITO/Si heterojunction. Due to an electrical conductive ITO film, ITO/Si heterojunction device can be operated at zero-bias, which effectively suppresses the dark current, resulting in better performances than those by a positive or a negative bias operation. This zero-bias operating heterojunction device exhibits a short response time (∼ 22.5 ms) due to the physical reaction to the incident light. We revealed that the location of the space charge region (SCR) is crucial for a specific photon-wavelength response. The SCR space has the highest collection efficiency of the photo-generated carriers. The photo-response can be maximized when we design the photodetector by superposing the SCR space over a corresponding photon-absorption length. The surface enhanced Si pillar devices significantly improved the photo-responses ratios from that of a planar Si device. According to this design scheme, a high photo-response ratio of 5560% was achieved at a wavelength of 600 nm. This surfaced-enhanced heterojunction design scheme would be a promising approach for various photoelectric applications.
Gacs quantum algorithmic entropy in infinite dimensional Hilbert spaces
Authors: Benatti Fabio , Oskouei Samad Khabbazi , Deh Abad Ahmad Shafiei
Published: August 2014

We extend the notion of Gacs quantum algorithmic entropy, originally formulated for finitely many qubits, to infinite dimensional quantum spin chains and investigate the relation of this extension with two quantum dynamical entropies that have been proposed in recent years.
Experimental investigation of factors limiting slow axis beam quality in 9xx nm high power broad area diode lasers
Authors: Winterfeldt M. , Crump P. , Wenzel H. , Erbert G. , Tränkle G.
Published: August 2014

GaAs-based broad-area diode lasers are needed with improved lateral beam parameter product (BPPlat) at high power. An experimental study of the factors limiting BPPlat is therefore presented, using extreme double-asymmetric (EDAS) vertical structures emitting at 910 nm. Continuous wave, pulsed and polarization-resolved measurements are presented and compared to thermal simulation. The importance of thermal and packaging-induced effects is determined by comparing junction -up and -down devices. Process factors are clarified by comparing diodes with and without index-guiding trenches. We show that in all cases studied, BPPlat is limited by a non-thermal BPP ground-level and a thermal BPP, which depends linearly on self-heating. Measurements as a function of pulse width confirm that self-heating rather than bias-level dominates. Diodes without trenches show low BPP ground-level, and a thermal BPP which depends strongly on mounting, due to changes in the temperature profile. The additional lateral guiding in diodes with trenches strongly increases the BPP ground-level, but optically isolates the stripe from the device edges, suppressing the influence of the thermal profile, leading to a BPP-slope that is low and independent of mounting. Trenches are also shown to initiate strain fields that cause parasitic TM-polarized emission with large BPPlat, whose influence on total BPPlat remains small, provided the overall polarization purity is >95%.
Effects of strain on effective work function for Ni/HfO2 interfaces
Authors: Zhong Kehua , Xu Guigui , Zhang Jian-Min , Huang Zhigao
Published: August 2014

The effective work functions for Ni/HfO2 interfaces under two strain modes (uniaxial and triaxial strains) were studied by using first-principles methods based on density functional theory. The calculated results indicate that the effective work functions are strongly affected by the type of interface and the strain states (tensile and compressive strains). For the both above strain states, the changed value of the effective work functions linearly increases with increasing strain. Moreover, it is observed that for a certain strain, the variation of the effective work function for triaxial strain state is almost larger than that for uniaxial strain state. Finally, the electrons gas model, the interface dipole, and screening role of HfO2 were used to analyze and explain the strain and interface effects in metal-oxide interfaces. The evident difference between the effective work functions of Ni-Hf and Ni-O interfaces is found to be attributed to different metallic bondings and ionic bondings via the analysis of the charge density distributions. Our work strongly suggests that controlling the strain and interface structure is a promising way for modulating the work function of Ni/HfO2 interfaces.
Photon assisted tunneling through three quantum dots with spin-orbit-coupling
Authors: Tang Han-Zhao , An Xing-Tao , Wang Ai-Kun , Liu Jian-Jun
Published: August 2014

The effect of an ac electric field on quantum transport properties in a system of three quantum dots, two of which are connected in parallel, while the third is coupled to one of the other two, is investigated theoretically. Based on the Keldysh nonequilibrium Green's function method, the spin-dependent current, occupation number, and spin accumulation can be obtained in our model. An external magnetic flux, Rashba spin-orbit-coupling (SOC), and intradot Coulomb interactions are considered. The magnitude of the spin-dependent average current and the positions of the photon assisted tunneling (PAT) peaks can be accurately controlled and manipulated by simply varying the strength of the coupling and the frequency of the ac field. A particularly interesting result is the observation of a new kind of PAT peak and a multiple-PAT effect that can be generated and controlled by the coupling between the quantum dots. In addition, the spin occupation number and spin accumulation can be well controlled by the Rashba SOC and the magnetic flux.
Plasmon resonance enhanced large third-order optical nonlinearity and ultrafast optical response in Au nanobipyramids
Authors: Yu Ying , Fan Shan-Shan , Dai Hong-Wei , Ma Zong-Wei , Wang Xia , Han Jun-Bo , Li Liang
Published: August 2014

The third-order optical nonlinearity and response time of Au nanobipyramids have been investigated by using optical Kerr effect technique. Large third-order nonlinear optical susceptibility (χ(3)) and ultrafast optical response time have been obtained at the longitudinal surface plasmon resonance (LSPR) wavelength. As the excitation laser wavelength varies from non-resonance wavelength of 780 nm to the LSPR wavelength of 825 nm, χ(3) increases from 7.4 × 10−14 to 3.9 × 10−13 esu, the fast component of the response time decreases from 141 ± 23 to 83 ± 8 fs and the ratio of the fast component remains around 48%, while the slow response time decreases from 3200 ± 200 to 2310 ± 158 fs. The large enhancement of χ(3) is due to the large local field enhancement caused by the surface plasmon resonance, and the shortening of the response times are induced by the increased probability of the electron-electron and electron-phonon scatterings in the nanosystem. This significant ultrafast optical property in Au nanobipyramids has great application in future ultrafast information processors.