bluuebunny/crossref_metadata_2025 huggingface dataset:
The plasma miR-125a, miR-361 and miR-133a are promising novel biomarkers for Late-Onset Hypogonadism
Authors: Chen Yao-ping , Wang Ju , Zhao Kai , Shang Xue-jun , Wu Hui-qin , Qing Xing-rong , Fang Fang , Zhang Yan , Shang Jin , Li Hong-gang , Zhang Hui-ping , Guan Huang-tao , Zhou Yuan-zhong , Gu Yi-qun , Wu Wei-xiong , Xiong Cheng-liang
Published: March 2016

Circulating miRNAs have been shown to serve as diagnostic/prognostic biomarkers in cancers and other diseases. However, the role of plasma miRNAs in Late-onset hypogonadism (LOH) diagnosis is still unknown. Using Illumina HiSeq2000 sequencing at discovery phase, and then two-step validated by reverse transcriptase polymerase chain reaction (RT-PCR) assays in verification phases. We verified that the expression levels of miR-125a-5p, miR-361-5p and miR-133a-3p were significantly altered in LOH group compared to the control group. The area under the receiver operating characteristic (ROC) curve (AUC) is 0.682, 0.698 and 0.765, respectively. The combination of three miRNAs showed a larger AUC (0.835) that was more efficient for the diagnosis of LOH. Among three miRNAs, miR-133a-3p had the best diagnostic value for LOH with 68.2% sensitivity and 77.3% specificity. Regression analyses show that miR-133a-3p level was negatively associated with the ageing males’ symptoms (AMS) scale. However, miR-361-5p level was positively associated with serum testosterone concentrations. In summary, plasma miRNAs are differentially expressed between LOH and healthy controls. We validated three miRNAs that could act as novel biomarkers for diagnosis of LOH. These miRNAs may be involved in the development of LOH. However, further large and functional studies are warranted to confirm our findings.
Possible interstellar formation of glycine through a concerted mechanism: a computational study on the reaction of CH2NH, CO2 and H2
Authors: Nhlabatsi Zanele P. , Bhasi Priya , Sitha Sanyasi
Published: March 2016

Computational studies on the reaction of CH2NH, CO2 and H2 show the possible interstellar formation of glycine in both hot-cores and cold interstellar clouds.
Facile preparation of β-/γ-MgH2 nanocomposites under mild conditions and pathways to rapid dehydrogenation
Authors: Xiao Xuezhang , Liu Zhe , Saremi-Yarahmadi Sina , Gregory Duncan H.
Published: March 2016

A γ-MgH2/β-MgH2 nanocomposite can be synthesized via a simple wet chemical route with THF, releasing 6.6 wt% H2 with rapid kinetics; initial hydrogen release arises either directly from meta-stable γ-MgH2 or immediately following its transformation into β-MgH2.
Calibration of57Fe Mössbauer constants by first principles
Authors: Casassa Silvia , Ferrari Anna Maria
Published: March 2016

Ab initioperiodic esimate of Mössbauer isomer shift and quadrupolar moment for iron: hybrid functional approach in a GTO basis set.
Is it possible to reverse aged acetylcholinesterase inhibited by organophosphorus compounds? Insight from the theoretical study
Authors: An Yun , Zhu Yali , Yao Yuan , Liu Junjun
Published: March 2016

The reaction mechanism for reversing an aged sarin–AChE adduct has been uncovered for the design of detoxification agents against organophosphorus compounds.
Targeting of DNA molecules, BSA/c-Met tyrosine kinase receptors and anti-proliferative activity of bis(terpyridine)copper(ii) complexes
Authors: Mahendiran Dharmasivam , Kumar Raju Senthil , Viswanathan Vijayan , Velmurugan Devadasan , Rahiman Aziz Kalilur
Published: March 2016

The newly synthesized bis(terpyridine)copper(ii) complexes may act as DNA-targeting metallo-anticancer agents to overcome cisplatin resistance.
A one-pot sequential five-component domino reaction for the expedient synthesis of polysubstituted pyrroles
Authors: Ambethkar Sethurajan , Padmini Vediappen , Bhuvanesh Nattamai
Published: March 2016

A new protocol towards the synthesis of polysubstituted pyrroles via enaminone from one-pot five-component reactions under catalyst free conditions.
Catalyst-free, one-pot, four-component green synthesis of functionalized 1-(2-fluorophenyl)-1,4-dihydropyridines under ultrasound irradiation
Authors: Shabalala Nhlanhla , Maddila Suresh , Jonnalagadda Sreekantha B.
Published: March 2016

A catalyst-free synthesis protocol for functionalized 1,4-dihydropyridines under ultrasonic irradiation in aqueous ethanol is reported with excellent yields. Eleven new compounds are synthesized using dimethylacetylenedicarboxylate, 2-fluoroaniline, malononitrile and various substituted aldehydes.
Phosphovanadomolybdic acid catalyzed desulfurization–oxygenation of secondary and tertiary thioamides into amides using molecular oxygen as the terminal oxidant
Authors: Xu Ning , Jin Xiongjie , Suzuki Kosuke , Yamaguchi Kazuya , Mizuno Noritaka
Published: March 2016

In the presence of phosphovanadomolybdic acids, secondary and tertiary thioamides could be converted into amides using molecular oxygen and water.
The synthesis and ring-opening metathesis polymerization of glycomonomers
Authors: Weaver Lucy G. , Singh Yogendra , Burn Paul L. , Blanchfield Joanne T.
Published: March 2016

The synthesis of a series of short poly(norbornene)s displaying pendant disaccharides is reported.
Novel thiosemicarbazide–oxadiazole hybrids as unprecedented inhibitors of yeast α-glucosidase and in silico binding analysis
Authors: Taha Muhammad , Ismail Nor Hadiani , Imran Syahrul , Wadood Abdul , Ali Muhammad , Rahim Fazal , Khan Aftab Ahmad , Riaz Muhammad
Published: March 2016

Novel hybrids of thiosemicarbazide–oxadiazole as potent α-glucosidase agents.
High-throughput metabolomics to identify metabolites to serve as diagnostic biomarkers of prostate cancer
Authors: Li Yuanfeng , Qiu Shi , Zhang Ai Hua
Published: March 2016

Prostate cancer (PCa) has long been known to exhibit unique metabolite profiles.
1,1-Disubstituted olefin synthesis via Ni-catalyzed Markovnikov hydroalkylation of alkynes with alkyl halides
Authors: Lu Xiao-Yu , Liu Jing-Hui , Lu Xi , Zhang Zheng-Qi , Gong Tian-Jun , Xiao Bin , Fu Yao
Published: March 2016

A Ni-catalyzed Markovnikov hydroalkylation of alkynes with alkyl halides is described.
Switchable probes: pH-triggered and VEGFR2 targeted peptides screening through imprinting microarray
Authors: Qian Yixia , Wang Weizhi , Wang Zihua , Han Qiuju , Jia Xiangqian , Yang Shu , Hu Zhiyuan
Published: March 2016

Here, we use an integrated imprinted microarray to screen out a switchable peptide probe, STP, with a novel sequence towards VEGFR2 in mild acidic conditions. In addition, STP has the characteristic of penetrating into cells in the presence of protons because its formation of an α-helix.
Graphdiyne oxide as a platform for fluorescence sensing
Authors: Wang Chunxia , Yu Ping , Guo Shuyue , Mao Lanqun , Liu Huibiao , Li Yuliang
Published: March 2016

Graphdiyne (GD), a new kind of two-dimensional carbon allotrope consisting of a hexagonal ring and a diacetylenic linkage unit, is observed to exhibit a high fluorescence quenching ability and can be used as a new platform for fluorescence sensing, where GD oxide, the oxidized form of GD, is found to exhibit higher quenching ability than GD.
The surface structure matters: thermal stability of phthalic acid anchored to atomically-defined cobalt oxide films
Authors: Xu Tao , Schwarz Matthias , Werner Kristin , Mohr Susanne , Amende Max , Libuda Jörg
Published: March 2016

The atomic structure of cobalt oxide surfaces influence the ordering and thermal stability of anchored phthalic acid.
Quantum and quasi-classical calculations for the S+ + H2(v,j) → SH+(v′,j′) + H reactive collisions
Authors: Zanchet Alexandre , Roncero Octavio , Bulut Niyazi
Published: March 2016

State-to-state cross-sections for the S+ + H2(v,j) → SH+(v′,j′) + H endothermic reaction are obtained using quantum wave packet (WP) and quasi-classical (QCT) methods for different initial ro-vibrational H2(v,j) over a wide range of translation energies.
Degradation mechanism(s) of GaAs solar cells with Cu contacts
Authors: van Leest R. H. , de Kleijne K. , Bauhuis G. J. , Mulder P. , Cheun H. , Lee H. , Yoon W. , van der Heijden R. , Bongers E. , Vlieg E. , Schermer J. J.
Published: March 2016

Description of the Cu related degradation mechanisms in GaAs solar cells due to exposure to elevated temperatures.
Mesostructured NiO/Ni composites for high-performance electrochemical energy storage
Authors: Lai Hongwei , Wu Qiang , Zhao Jin , Shang Longmei , Li He , Che Renchao , Lyu Zhiyang , Xiong Jingfang , Yang Lijun , Wang Xizhang , Hu Zheng
Published: March 2016

The mesostructured NiO/Ni composites boost the electrochemical energy storage performance of NiO to its theoretical limit, which results from the synergism of high accessibility to electrolyte, short solid-state ion diffusion length and high conductivity owing to the unique mesostructure.
Correction: 2D phosphorene as a water splitting photocatalyst: fundamentals to applications
Authors: Rahman Mohammad Ziaur , Kwong Chi Wai , Davey Kenneth , Qiao Shi Zhang
Published: March 2016

Correction for ‘2D phosphorene as a water splitting photocatalyst: fundamentals to applications’ by Mohammad Ziaur Rahman et al., Energy Environ. Sci., 2016, 9, 709–728.
Bio-assay guided identification of hepatoprotective polyphenols from Penthorum chinense Pursh on t-BHP induced oxidative stress injured L02 cells
Authors: Wang Anqi , Wang Shengpeng , Jiang Yun , Chen Meiwan , Wang Yitao , Lin Ligen
Published: March 2016

This study identified an active fraction and quercetin as chemical principles for the traditional hepatoprotective herb Penthorum chinense.
Production of C4 and C5 alcohols from biomass-derived materials
Authors: Sun Daolai , Sato Satoshi , Ueda Wataru , Primo Ana , Garcia Hermenegildo , Corma Avelino
Published: March 2016

The present critical review focuses on the production of C4, C5 diols and monoalcohols from precursors derived from the biomass.
Ring opening metathesis polymerization of cyclopentene using a ruthenium catalyst confined by a branched polymer architecture
Authors: Mugemana Clément , Bukhryakov Konstantin V. , Bertrand Olivier , Vu Khanh B. , Gohy Jean-François , Hadjichristidis Nikos , Rodionov Valentin O.
Published: March 2016

A Grubbs-type Ru alkene metathesis catalyst has been covalently anchored in the core of a globular star polymer. The spatially-confined catalyst is capable of efficient ring-opening metathesis polymerization of cyclopentene, a low-strain monomer.
Synthesis and properties of novel chiral imidazolium-based ionic liquids derived from carvone
Authors: Santamarta Francisco , Vilas Miguel , Tojo Emilia , Fall Yagamare
Published: March 2016

A large series of novel chiral imidazolium ionic liquids were synthesized using the terpenoid carvone as the chiral substrate.
Design of functional cationic microgels as conjugation scaffolds
Authors: Kodlekere Purva , Cartelle Anabel Liyen , Lyon L. Andrew
Published: March 2016

We describe the development of primary amine functionalized microgels with the potential as dye scaffolds for bioimaging.
Soft template induced phase selective synthesis of Fe2O3nanomagnets: one step towards peroxidase-mimic activity allowing colorimetric sensing of thioglycolic acid
Authors: Roy Anindita , Sahoo Ramkrishna , Ray Chaiti , Dutta Soumen , Pal Tarasankar
Published: March 2016

The peroxidase-mimicking property of the soft template mediated phase selective α- and γ-Fe2O3magnetic nanoparticles allows colorimetric sensing for thioglycolic acid down to μM level.
Studies towards a greener diazo transfer methodology
Authors: Tarrant Elaine , O'Brien Claire V. , Collins Stuart G.
Published: March 2016

A mild, efficient and green method has been developed for diazo transfer to β-ketoesters using polystyrene-supported benzenesulfonyl azide, water as solvent and catalytic base.
Improving the electrochemical performance of Li1.2Mn0.52Co0.13Ni0.13O2 by surface nitrogen doping via plasma treatment
Authors: Li Bing , Li Chao , Cao Zulai , wang Jing , Zhao Jinbao
Published: March 2016

A facile and effective route to introduce nitrogen on the surface of a material with improved electrochemical performance.
Nickel core–palladium shell nanoparticles grown on nitrogen-doped graphene with enhanced electrocatalytic performance for ethanol oxidation
Authors: Zhang Mingmei , Li Yuan , Pan Denghui , Yan Zaoxue , Meng Suci , Xie Jimin
Published: March 2016

Herein, we report a facile two-step strategy for green synthesis of nickel core–palladium shell nanoclusters on nitrogen-doped graphene (Ni@Pd/NG) without any surfactant and additional reducing agent.
Upgrading of aromatic compounds in bio-oil over ultrathin graphene encapsulated Ru nanoparticles
Authors: Shi Juanjuan , Zhao Mengsi , Wang Yingyu , Fu Jie , Lu Xiuyang , Hou Zhaoyin
Published: March 2016

A novel Ru@G-CS composite, in which 1–2 layered N-doped graphene encapsulated nano-sized Ru (2.5 ± 1.0 nm) particles, was fabricated on carbon sheets (CS) via the direct pyrolysis of mixed glucose, melamine and RuCl3. And Ru@G-CS-700 (pyrolysis at 700 °C) is highly active, selective and stable for the hydrogenation of model compounds (such as phenols, furfurals and aromatics) in bio-oil in water.
High mobility transistors based on electrospray-printed small-molecule/polymer semiconducting blends
Authors: Pitsalidis C. , Pappa A. M. , Hunter S. , Laskarakis A. , Kaimakamis T. , Payne M. M. , Anthony J. E. , Anthopoulos T. D. , Logothetidis S.
Published: March 2016

An electrospray-printing technique was employed for the fabrication of OFETs based on small-molecule:semiconducting polymer blends.
Kinetic characterization and regulation of the human retinaldehyde dehydrogenase 2 enzyme during production of retinoic acid
Authors: Shabtai Yehuda , Jubran Halim , Nassar Taher , Hirschberg Joseph , Fainsod Abraham
Published: March 2016

Retinoic acid (RA) is an important regulator of embryogenesis and tissue homoeostasis. Perturbation of RA signalling causes developmental disorders, osteoarthritis, schizophrenia and several types of tumours. RA is produced by oxidation of retinaldehyde from vitamin A. The main enzyme producing RA in the early embryo is retinaldehyde dehydrogenase 2 (RALDH2, ALDH1A2). In the present study we describe in depth the kinetic properties and regulation of the human RALDH2 (hRALDH2) enzyme. We show that this enzyme produces RA using in vivo and in vitro assays. We studied the naturally occurring all-trans-, 9-cis- and 13-cis-retinaldehyde isomers as substrates of hRALDH2. Based on the values measured for the Michaelis–Menten constant Km and the maximal rate Vmax, in vitro hRALDH2 displays the same catalytic efficiency for their oxidation. We characterized two known inhibitors of the vertebrate RALDH2 and determined their kinetic parameters on hRALDH2. In addition, RA was studied as a possible inhibitor of hRALDH2 and a regulator of its activity. We show that hRALDH2 is not inhibited by its oxidation product, all-trans-RA, suggesting the absence of a negative feedback regulatory loop. Expression of the Raldh2 gene is known to be regulated by RA itself, suggesting that the main regulation of the hRALDH2 activity level is transcriptional.
Memory characteristics of capacitors with poly‐GaAs floating gates
Authors: Roh I.P. , Kang N.S. , Shin S.H. , Oh Y.T. , Kim K.B. , Song J.D. , Song Y.H.
Published: March 2016

The memory characteristics of a capacitor with polycrystalline gallium arsenide (poly‐GaAs) as a floating gate material have been evaluated, and compared with a capacitor using poly‐silicon (poly‐Si). The poly‐GaAs film with thickness of 100 nm was successfully grown on silicon at 250°C, using an arsenide beam flux, in a molecular beam epitaxy chamber. Based on the optical and electrical evaluation, this film appeared to have obvious poly‐GaAs. Here, the measured the memory window by comparing it to a conventional device with a poly‐Si floating gate, which showed it to have approximately twice the value of the poly‐Si. Based on these results, poly‐GaAs floating material can be considered to be a candidate for a wider memory window in scaled two‐dimensional flash memory.
Specular component‐based beamforming for broadband massive MIMO systems with doubly‐ended correlation
Authors: Yue Dian‐Wu
Published: March 2016

Beamforming (BF) transmission for broadband massive MIMO systems in frequency‐selective Ricean fading environments is investigated. By treating the scattered component as interference in order to reduce the heavy overhead for estimating channel state information, a transmit/receive BF scheme only based on the specular component is presented. It is shown by analytical results that the ergodic achievable rate for the scenario with doublyended spatial correlation can be asymptotically equal to that of the one without correlation when the transmit power is scaled down by the multiplication of the two numbers of antennas at the transmitter and the receiver. It is also shown by simulation results that different from the traditional point of view, spatial correlation can improve the rate performance of the proposed BF scheme.
Groove gap waveguide as an alternative to rectangular waveguide for H‐plane components
Authors: Berenguer A. , Sánchez‐Escuderos D. , Bernardo‐Clemente B. , Baquero‐Escudero M. , Boria V.E.
Published: March 2016

A comparative study between groove gap waveguide (GGW) technology and classical H‐plane rectangular waveguide (RWG) technology is presented by evaluating their performance in the implementation of a narrow‐band filter at the V‐band. A filter with the same specifications has been manufactured and measured for each technology. Measured responses are compared and a re‐assembling robustness test is carried out. The GGW filter presents a better response and remains completely invariant to the re‐assembling process, which is shown to affect notably the RWG filter response. Remarkable low insertion loss of only 1.5 dB (cavities equivalent quality factor higher than 800) is obtained for the GGW filter.
Laterally coupled distributed feedback cascade diode lasers emitting near 2.9 µm
Authors: Hosoda T. , Fradet M. , Frez C. , Shterengas L. , Sander S. , Forouhar S. , Belenky G.
Published: March 2016

Cascade type‐I quantum well GaSb‐based laterally coupled distributed feedback diode lasers emitting near 2.9 µm were designed and fabricated. Second order index grating with period of 825 nm was defined by e‐beam lithography and etched on both sides of 4‐µm‐wide shallow ridge waveguide. Anti‐/neutral reflection coated 2‐mm‐long devices that were solder‐mounted epitaxial side‐up demonstrated stable single frequency operation in a wide temperature range with output power of 13 mW at 20°C. Bragg wavelength temperature tuning rate was ∼0.32 nm/K.
High power eye‐safe Er3+:YVO4 laser diode‐pumped at 976 nm
Authors: Newburgh G.A. , Dubinskii M.
Published: March 2016

The performance of an eye‐safe laser based on a Er‐doped orthovanadate (Er:YVO4) single crystal, diode‐pumped at 976 nm (4I15/2 → 4I11/2 transition) and operating at 1603 nm (4I13/2 → 4I15/2 transition) with near diffraction limited beam quality is reported. A 10 mm long Er3+:YVO4 slab, cut with its c‐axis perpendicular to the laser cavity axis, was pumped in σ‐polarisation and lased in π‐polarisation. The laser operated in a quasi‐continuous wave regime with nearly 9 W output power, and with a slope efficiency of about 39% with respect to absorbed power. This is believed to be the highest efficiency and highest power achieved from an Er3+:YVO4 laser pumped in the 970–980 nm absorption band.
Compact full Ka‐band waveguide directional coupler based on large aperture array
Authors: Deng Xida , Wang Zhigang , Xu Kaida , Yan Bo
Published: March 2016

A compact full Ka‐band waveguide directional coupler based on novel aperture array is presented. The broadband, good in‐band coupling flatness and excellent return loss are achieved by using the proposed novel aperture array in the common broad wall of two paralleled waveguides. For verification purpose, a prototype of the proposed directional coupler has been designed, fabricated and measured. The experimental results show that the return loss and isolation of the proposed coupler are better than 28 and 30 dB, respectively, and coupling strength varies from −20.35 to −19.23 dB over the full waveguide bandwidth. The length of the coupling region is only 8.5 mm.
Continuous‐time four‐quadrant modulator with inherent PVT cancellation
Authors: Al‐Tamimi K. , Thiyagarajan P. , El‐Sankary K.
Published: March 2016

A continuous‐time four‐quadrant multiplier in subthreshold region is presented. Besides its simplicity, the structure features inherent process–voltage–temperature (PVT) variation cancellation while working under low voltage supply and dissipating an ultra‐low power. The PVT variation was alleviated through an inherent log/anti‐log cancellation technique, making it as a good candidate for bio‐potential acquisition systems. The input and output signals are currents resulting in a wider bandwidth and larger dynamic range compared with the voltage‐mode counterparts. The circuit is versatile and can be configured as a modulator, frequency doubler, and linear variable gain amplifier as shown in theory and simulation results.
Distributed perceptual compressed sensing framework for multiview images
Authors: Elsayed S. , Elsabrouty M. , Muta O. , Furukawa H.
Published: March 2016

A perceptual‐based compressed sensing (CS), which focuses the measurements and the recovery on the visually important low‐frequency coefficients, is applied for multi‐view image signals. High correlation among different views is exploited to generate signal prediction using disparity estimation and compensation techniques. A residual‐based recovery is utilised as a joint recovery for the non‐reference images to enhance the reconstruction performance. The proposed framework shows remarkable performance improvement over the conventional CS with joint recovery as well as the perceptual‐based CS with independent recovery.
Fractional‐N PLL with multi‐element fractional divider for noise reduction
Authors: Sanyal Arindam , Yu Xueyi , Zhang Yanlong , Sun Nan
Published: March 2016

A novel technique to suppress quantisation noise in a ΔΣ fractional‐N phase‐locked loop (PLL) using a fine‐resolution multi‐element fractional divider is presented. The proposed technique suppresses noise uniformly over the entire frequency range. It is mostly digital and is applicable for both analogue and digital PLLs. The proposed technique with an eight‐element fractional divider can suppress the quantisation noise by 18 dB compared with a conventional fractional‐N PLL.
Asynchronous amplify‐and‐forward relay communications for underwater acoustic networks
Authors: Cao Rui , Qu Fengzhong , Yang Liuqing
Published: March 2016

Underwater acoustic communications (UAC) feature frequency‐dependent signal attenuation, long propagation delay and doubly‐selective fading. Thus the design of reliable UAC protocols is challenging. On the other hand, cooperative relay communications, which have been extensively studied in terrestrial environments, are promising paradigms for reliable communications. However, their application to UAC has not been thoroughly explored. In this study, the authors will design an asynchronous relaying protocol to achieve reliable underwater communications. This new scheme accounts for and takes advantage of the unique characteristics of UAC channels. To avoid time synchronisation difficulty in UAC, and facilitate energy‐efficient relay processing, asynchronous amplify‐and‐forward relaying is adopted in the protocol. In addition, precoded orthogonal frequency division multiplexing is chosen to address the frequency selectivity issue in UAC, while collecting ample multipath diversity provided by the channel and enabled by the asynchronous relaying design. To demonstrate the performance of the protocol, the end‐to‐end signal‐to‐noise ratio is derived, the average pair‐wise error probability is evaluated and the maximum collectable diversity is also proven. Simulations and comparisons are presented to corroborate the analyses and design.
Performance analysis of free space optical communication in open‐atmospheric turbulence conditions with beam wandering compensation control
Authors: Raj Anthonisamy Arockia Bazil , Durairaj Padmavathi , James Paul Lancelot
Published: March 2016

Among various atmospheric effects, beam wandering is the main cause for the major power loss in free space optical communication (FSOC) which cannot be resolved without incorporating the beam wandering compensation (BWC) control. To prove this prerequisite, a 155 Mbps data transmission experimental setup is built with necessary optoelectronic components for the link range of 0.5 km at an altitude of 15.25 m. A neuro‐controller is developed inside the field programmable gate array and used to stabilise the received beam at the centre of the detector plane so as to perfectly couple the power in the bucket to the optical detector. The Q‐factor and bit error rate variation profiles are calculated using the signal statistics obtained from the eye‐diagram. The performance improvements on the FSOC system due to the incorporation of BWC control are investigated and discussed in terms of various communication quality assessment key parameters.
Contract‐auction based distributed resource allocation for cooperative communications
Authors: Nazari Bahareh , Jamalipour Abbas
Published: March 2016

Cooperative communication significantly improves the performance of wireless systems. Transmission of signal in such a system can be accomplished by the help of intermediate relay nodes. However, due to the selfish nature of network nodes, an incentive mechanism is required to stimulate relay nodes to cooperate. On the other hand, the authors assume that the source nodes are ill‐informed about channel conditions of the relay nodes, which may result in asymmetry of information. In this study, the authors propose a distributed power allocation and price assignment algorithm over cooperative wireless networks. The proposed solution aims to achieve optimum power allocation to the source nodes and best price of power at the relay nodes, in the presence of asymmetric channel state information. To this end, the authors combine contract theory and auction mechanism in order to provide the highest possible utility for both the source and the relay nodes. The proposed distributed approach benefits the source nodes by preventing the relay nodes from cheating behaviour. Additionally, it favours the relay nodes by letting them assign the final price of power. Finally, the authors present simulation results in order to demonstrate efficiency of the proposed distributed multi‐user algorithm.
Channel estimation for multi‐input multi‐output relay systems using the PARATUCK2 tensor model
Authors: Du Jianhe , Yuan Chaowei , Tian Pei , Lin Heyun
Published: March 2016

In this study, the authors present a novel channel estimation algorithm for three‐hop multi‐input multi‐output (MIMO) relay systems using the PARATUCK2 tensor model. At the destination, the proposed algorithm exploits a unified formulation of the received signal as a PARATUCK2 model, and jointly estimates all of the channel matrices involved in the communication. Compared with existing algorithms, the proposed algorithm only requires the source to transmit the channel training sequences, does not need relays to perform any task of channel estimation, and yields smaller estimation error. Moreover, the proposed algorithm can be extended to multi‐hop MIMO relay systems with any number of hops. Numerical examples are shown to demonstrate the effectiveness of the PARATUCK2‐based channel estimation algorithm.
Further results on degree‐2 perfect Gaussian integer sequences
Authors: Lee Chong‐Dao , Li Chih‐Peng , Chang Ho‐Hsuan , Wang Sen‐Hung
Published: March 2016

A complex number whose real and imaginary parts are both integers is called a Gaussian integer. A Gaussian integer sequence is said to be perfect if it has an ideal periodic autocorrelation function (PACF) where all out‐of‐phase values are zero. Further, the degree of a Gaussian integer sequence is defined as the number of distinct non‐zero Gaussian integers within one period of the sequence. Recently, the perfect Gaussian integer sequences have been found important practical applications as signal processing tools for orthogonal frequency‐division multiplexing systems. The present article generalises the authors’ earlier paper by Lee et al. (2015) related to the Gaussian integer sequences with ideal PACFs. By the applications of two‐tuple‐balanced binary sequences and cyclic difference sets, a number of new degree‐2 perfect Gaussian integer sequences with different periods are obtained.
Recursive fast terminal sliding mode control in voltage source inverter for a low‐voltage microgrid system
Authors: Gudey Satish Kumar , Gupta Rajesh
Published: March 2016

This study proposes a recursive fast terminal sliding mode control (FTSMC) for a low‐voltage microgrid system operating in grid connected and islanding mode of operation. The microgrid is presumed to be a higher order distribution system. A recursive approach of FTSMC is used in the voltage source inverter to control the bus voltage nearer to the main grid and farther away from the micro source in a grid connected system. Using this methodology good tracking of the bus voltage in case of grid connection and output voltage in case of islanding mode with a faster convergence is observed. The controlled voltage has low total harmonic distortion and small steady‐state error. The algorithm requires only single voltage sensing requirement for control operation. This study also reveals the inability of the classical sliding mode control for regulating the bus voltage which is at a far end of the microgrid system. The PSCAD/EMTDC software (version 4.2) has been used for simulation studies. The experimental results are shown for a scaled down model using LabVIEW programmed field‐programmable gate array controller in islanded mode of operation to verify the performance of the proposed FTSMC.
Thermal balance diagram modelling of surge arrester for thermal stability analysis considering ZnO varistor degradation effect
Authors: Seyyedbarzegar Seyyed Meysam , Mirzaie Mohammad
Published: March 2016

This study proposes a new method for modelling of metal‐oxide surge arresters (MOSAs) thermal balance diagram based on power loss and heat dispersion curve. Adaptive network‐based fuzzy inference system (ANFIS)‐based method was offered to compute surge arrester power loss characteristic. Thermal stability (TS) of surge arrester, which is analysed by thermal balance diagram, has a great influence on their proper functions. MOSA material variation is an important factor that has an influence on its TS. Degradation factor (DF) was introduced as a new index in this study to represent material variations of MOSA. Therefore, applied voltage, temperature and DF were considered as inputs in ANFIS model to obtain accurate power loss which is a very important factor in TS characteristic. Heat dispersion curve was obtained as a main feature in the thermal balance diagram from surge arrester cooling curve. Degrading effect was considered using voltage and current measured from MOSA which are degraded by utilisation in the network. In addition, effect of assembling process has been considered by using new different varistors in experimental measurements. This study shows that the thermal balance diagram of surge arrester is predictable with a good accuracy by using artificial model.
Aerial line model for power system electromagnetic transients simulation
Authors: Garcia‐Sanchez Jorge Luis , Moreno Pablo , Gutierrez‐Robles José Alberto , Loo‐Yau José Raul , Sotelo Julián , Bañuelos Eduardo Salvador , Galván Verónica Adriana
Published: March 2016

In this study, a new model for aerial multiconductor transmission lines with frequency dependent electrical parameters is presented. The new model is called here A‐line model and is a two‐port model based on the method of characteristics and finite differences that does not require segmenting the transmission line. The frequency dependence of electrical parameters due to field penetration in conductors and Earth is taken into account by means of the penetration impedance or skin impedance. Moreover, in the proposed model there is no need of splitting in propagation modes; therefore, the numerical implementation is very simple. With the purpose of validation, results from the numerical Laplace transform and universal line model are employed. From the results, it is found that the A‐line model is accurate and robust with an execution speed that makes it a strong candidate for real‐time simulations.
Application of high‐order Newton‐like methods to solve power flow equations
Authors: Derakhshandeh Sayed Yaser , Pourbagher Rohallah
Published: March 2016

Solving the power flow (PF) equations based on Newton–Raphson technique has been considered in the literatures since the late 1960s. Ever since, various types of studies have been presented about the solution of the PF problem. The main purpose of the presented methods is to decrease the computation time. This study presents applying the third‐, fourth‐ and fifth‐order Newton‐like methods to solve the PF problem in power systems. Using the third‐, fourth‐ and fifth‐order methods in solving the PF problem can significantly reduce the computation time and the number of iterations. The proposed formulations and algorithms are tested on standard 9‐, 14‐, 30‐, 57‐, 118‐ and 2383‐bus systems and the results are reported and discussed.
Control strategy of interlinking converters as the key segment of hybrid AC–DC microgrids
Authors: Baharizadeh Mehdi , Karshenas Hamid Reza , Guerrero Josep M.
Published: March 2016

This study is concerned with presenting control strategy for interlink converters in hybrid microgrids. When both ac microgrids (AC‐MGs) and dc microgrids are in the vicinity of each other, they can be interconnected via ac–dc converters, known as ICs, making it possible to exchange energy between two grids. Common methods employed in IC control strategy use frequency variation and CCM in their structure. This method requires the frequency variation at IC ac‐side to be large, leading to poor power quality and stability of AC‐MG. Furthermore, CCM does not directly regulate the IC ac‐side voltage, which again deteriorates the IC ac‐side voltage quality. The proposed strategy is based on droop method, similar to what is used in the autonomous control of sources in an AC‐MG. This technique uses voltage‐controlled method and does not need frequency measurement in its structure. This considerably improves the voltage quality of AC‐MG. The derivation of appropriate droop characteristic is explained. Time‐domain simulation is used to verify the performance of the proposed method. The small‐signal stability of the system is studied. It is shown how by introducing a proper virtual impedance, the small‐signal stability of the system can be improved.
Probabilistic load flow calculation using cumulants and multiple integrals
Authors: Wu Wei , Wang Keyou , Li Guojie , Jiang Xiuchen , Wang Zhiming
Published: March 2016

Probabilistic load flow (PLF) is a powerful and widely used tool to address the random nature of renewable energy resources for the planning and operation of power systems. In this study, a new approach using a combination of the multiple integral method (MIM) and the cumulant method (CM) is proposed for PLF studies. The PLF problem with high dimensionality is decomposed into a bi‐level problem and solved by MIM and CM to reduce the computational burden significantly while achieving satisfactory accuracy. The proposed method is applied to the IEEE 118‐bus system and is compared with CM and point estimate method. Simulation results show that the proposed method achieves great computational efficiency and accuracy.
Phase‐space‐based symmetrical fault detection during power swing
Authors: Dubey Rahul , Samantaray Subhransu Ranjan , Panigrahi Bijay Ketan , Venkoparao Vijendran G.
Published: March 2016

This study proposes an effective symmetrical fault detection technique during power swing in distance relaying using phase‐space (PS) method. This is based on an embedding theorem which shows that a time series can be mapped to a higher‐dimensional space called PS through embedding. Thus, a sampled signal can be transformed into the PS so that its features can be more clearly viewed. The process starts at retrieving the current signal samples and process through PS, the original signal is decoupled into two parts such as power swing and symmetrical fault part. The symmetrical fault detection during power swing is easily achieved as the symmetrical fault part of the signal produces an irregular shape compared with the shape produced during from the power swing condition. The symmetrical fault detection signal using PS (FDPS) detects the symmetrical fault during power swing in the transmission line with wide variations in operating conditions and the results from extensive studies indicate that the proposed FDPS can reliably detect the faults during power swing.
Developed generalised unified power flow controller model in the Newton–Raphson power‐flow analysis using combined mismatches method
Authors: Kamel Salah , Jurado Francisco , Chen Zhe , Abdel‐Akher Mamdouh , Ebeed Mohamed
Published: March 2016

This study proposes the generalised unified power flow controller (GUPFC) model in the hybrid current power mismatch Newton–Raphson formulation (HPCIM). In this model, active power, real and imaginary current components are injected at the terminals of series impedances of GUPFC. These injected values are calculated during the iterative process based on the desired controlled values and buses voltage at the terminals of GUPFC. The parameters of GUPFC can be calculated during the iterative process and the final values are updated after load flow convergence. Using the developed GUPFC model, the original structure and symmetry of the admittance and Jacobian matrices can still be kept, the changing of Jacobian matrix is eliminated. Consequently, the complexities of the computer load flow program codes with GUPFC are reduced. The HPCIM load flow code with the proposed model is written in C++ programming language. Where, the SuperLU library is utilised to handle the sparse Jacobian matrix. The proposed model has been validated using the standard IEEE test systems.
Efficiency degradation of short‐distance wireless power transmission by distance alignment error
Authors: Iigusa Kyoichi , Sawada Hirokazu , Kojima Fumihide , Harada Hiroshi , Yano Hiroyuki
Published: March 2016

The optimal values of the circuit parameters with which the maximum efficiency of a short‐distance wireless power transmission is attained, depend on the transmission distance. The distance dependence of the maximum efficiency and the optimal circuit parameters are numerically investigated by classifying the causes of efficiency degradation into impedance mismatching of the transmitting antenna, radiation loss, and ohmic loss. The degradation of the transmission efficiency by the distance alignment error when the circuit parameters are fixed to the optimal values is further investigated. It is shown that the degradation caused by impedance mismatching of a transmitting antenna is steeper than that caused by radiation and ohmic loss when optimised transmission distance is shorter than ∼0.1 λ.
Dispersion optimised plane wave sources for scattering analysis with integral based high order finite difference time domain methods
Authors: Bollimuntha Ravi C. , Hadi Mohammed F. , Piket‐May Melinda J. , Elsherbeni Atef Z.
Published: March 2016

The implementation of plane wave incidence using the total‐field/scattered‐field (TFSF) formulation for a three‐dimensional finite volumes‐based, extended‐stencil finite‐difference time‐domain (FV24) algorithm is presented. This achievement required designing an auxiliary one‐dimensional grid with the characteristics of (i) co‐located electric field components uniformly spaced from co‐located magnetic field components, (ii) grid spacing that dynamically changes with desired angles of propagation to eliminate the need for field interpolations when mapping the plane wave to the main grid, (iii) update equations that precisely match the numerical dispersion characteristics of the main FV24 algorithm, and (iv) auxiliary to main grid field mapping that encompasses six parallel surfaces along the TFSF boundary to satisfy the extended cell nature of the main FV24 algorithm. The resulting non‐physical field leakage into the scattered‐field region is observed to be independent of angle of incidence and has a −300 dB noise floor. This technique extends the high‐order FV24 capabilities to include accurate and efficient simulations of electrically large scatterers using relatively low grid densities, bringing this capability to today's desk‐side workstations.
Experimental investigation on the synthesis of scanning beam pattern with antenna selection for conformal array
Authors: Sun Bin , Ren Bo , Liu Chunheng , Liu Yang , Yongzhen Li , Wang Xuesong
Published: March 2016

In this study, the synthesis of scanning beam pattern with antenna selection for practical half‐circular conformal array is achieved based on hybrid particle swarm optimisation‐gravitational search algorithm (PSOGSA). A half‐circular conformal dipole antenna system has been designed, fabricated and tested. The antenna element is dipole, and the digital beam forming net can control both the amplitude and phase in each channel through attenuator and phase shifter. The array confirms to a surface of half‐circular metal carrier. To achieve the synthesis of scanning beam pattern with activated antenna selection, hybrid PSOGSA is introduced to optimise the excitation amplitude. To consider the mutual coupling effect, embedded element pattern is measured and utilised. Numerical comparisons and practical experimental results illustrate the advantage and accuracy of the proposed method and manufactured system in the synthesis of scanning beam and activated element selection.
Predicting antenna pattern degradations in microstrip reflectarrays through interval arithmetic
Authors: Rocca Paolo , Poli Lorenzo , Anselmi Nicola , Salucci Marco , Massa Andrea
Published: March 2016

The effects on the antenna power pattern of the tolerances in etching the microstrip patches and in the knowledge of the substrate characteristics of reflectarray antennas are predicted with an approach based on the arithmetic of intervals and the interval analysis (IA). The uncertainties on the geometric and electric antenna parameters are defined as intervals and the rules of IA are applied to determine the bounds of deviation of the actual power pattern with respect to the nominal pattern. A set of representative results is reported to validate the proposed approach and to show its reliability and efficiency when considering different tolerance errors and various operational conditions.
Isotropic and nematic liquid crystalline phases of adaptive rotaxanes
Authors: He Hao , Sevick Edith M. , Williams David R. M.
Published: March 2016

We describe the thermodynamics of a solution of rotaxanes which can change their length from a short state of length L to a long state of length qL in response to their surrounding environment. We call these rotaxanes “adaptive.” We show that such a system can exhibit both isotropic and nematic liquid crystalline phases. The system shows several interesting kinds of behaviour. First we predict that the fraction of short-length rotaxanes increases linearly with concentration and is a maximum at the critical concentration that marks the isotropic to nematic transition. Second, the critical concentration shows a minimum at a certain value of q. Our model suggests that the effect of adaptive length changes is most dramatic at small q and where the long state is slightly favoured.
Anomalous open-circuit voltage from a high-Tc superconducting dynamo
Authors: Bumby C. W. , Jiang Zhenan , Storey J. G. , Pantoja A. E. , Badcock R. A.
Published: March 2016

We report on the behavior of a high-Tc superconducting (HTS) homopolar dynamo which outputs a DC open-circuit voltage when the stator is in the superconducting state, but behaves as a conventional AC alternator when the stator is in the normal state. We observe that this time-averaged DC voltage arises from a change in the shape of the AC voltage waveform that is obtained from a normal conducting stator. The measured DC voltage is proportional to frequency, and decreases with increasing flux gap between the rotor magnet and the HTS stator wire. We observe that the DC output voltage decreases to zero at large flux gaps, although small differences between the normal-conducting and superconducting waveforms are still observed, which we attribute to screening currents in the HTS stator wire. Importantly, the normalised pulse shape is found to be a function of the rotor position angle only. Based on these observations, we suggest that the origin of this unexpected DC effect can be explained by a model first proposed by Giaever, which considers the impact of time-varying circulating eddy currents within the HTS stator wire. Such circulating currents form a superconducting shunt path which “short-circuits” the high field region directly beneath the rotor magnet, at those points in the cycle when the rotor magnet partially overlaps the superconducting stator wire. This reduces the output voltage from the device during these periods of the rotor cycle, leading to partial rectification of the output voltage waveform and hence the emergence of a time-averaged DC voltage.
Effects of fuel-capsule shimming and drive asymmetry on inertial-confinement-fusion symmetry and yield
Authors: Séguin F. H. , Li C. K. , DeCiantis J. L. , Frenje J. A. , Rygg J. R. , Petrasso R. D. , Marshall F. J. , Smalyuk V. , Glebov V. Yu. , Knauer J. P. , Sangster T. C. , Kilkenny J. D. , Nikroo A.
Published: March 2016

Three orthogonal proton emission imaging cameras were used to study the 3D effects of low-mode drive asymmetries and target asymmetries on nuclear burn symmetry and yield in direct-drive, inertial-confinement-fusion experiments. The fusion yield decreased quickly as the burn region became asymmetric due to either drive or capsule asymmetry. Measurements and analytic scaling are used to predict how intentionally asymmetric capsule shells could improve performance by compensating for drive asymmetry when it cannot be avoided (such as with indirect drive or with polar direct drive).
Determination of anharmonic free energy contributions: Low temperature phases of the Lennard-Jones system
Authors: Calero C. , Knorowski C. , Travesset A.
Published: March 2016

We investigate a general method to calculate the free energy of crystalline solids by considering the harmonic approximation and quasistatically switching the anharmonic contribution. The advantage of this method is that the harmonic approximation provides an already very accurate estimate of the free energy, and therefore the anharmonic term is numerically very small and can be determined to high accuracy. We further show that the anharmonic contribution to the free energy satisfies a number of exact inequalities that place constraints on its magnitude and allows approximate but fast and accurate estimates. The method is implemented into a readily available general software by combining the code HOODLT (Highly Optimized Object Oriented Dynamic Lattice Theory) for the harmonic part and the molecular dynamics (MD) simulation package HOOMD-blue for the anharmonic part. We use the method to calculate the low temperature phase diagram for Lennard-Jones particles. We demonstrate that hcp is the equilibrium phase at low temperature and pressure and obtain the coexistence curve with the fcc phase, which exhibits reentrant behavior. Several implications of the method are discussed.