bluuebunny/crossref_metadata_2025 huggingface dataset:
Genomic methylation patterns in archaeological barley show de-methylation as a time-dependent diagenetic process
Authors: Smith Oliver , Clapham Alan J. , Rose Pam , Liu Yuan , Wang Jun , Allaby Robin G.
Published: July 2014

Genomic methylation is variable under biotic and abiotic stresses in plants. In particular, viral infection is thought to significantly increase genomic methylation with particularly high activity around transposable elements. Here we present the genomic methylation profiles of grains of archaeological barley (Hordeum vulgare) from several strata from a site in southern Egypt, from the Napatan to the Islamic periods (800 BCE – 1812 CE). One sample tested positive for viral infection and exhibits an unusually high degree of genomic methylation compared to the rest. A decreasing trend in global methylation levels according to deposition date shows in-situ de-methylation of 5-methylcytosine, which can be described as a diagenetic process. This is most likely a deamination mediated de-methylation process and is expected to lead to 5 mC > T base modifications in addition to the C > U modifications due to cytosine deamination, so represents a time-dependent process of DNA diagenesis in ancient DNA.
All-optical differential equation solver with constant-coefficient tunable based on a single microring resonator
Authors: Yang Ting , Dong Jianji , Lu Liangjun , Zhou Linjie , Zheng Aoling , Zhang Xinliang , Chen Jianping
Published: July 2014

Photonic integrated circuits for photonic computing open up the possibility for the realization of ultrahigh-speed and ultra wide-band signal processing with compact size and low power consumption. Differential equations model and govern fundamental physical phenomena and engineering systems in virtually any field of science and engineering, such as temperature diffusion processes, physical problems of motion subject to acceleration inputs and frictional forces and the response of different resistor-capacitor circuits, etc. In this study, we experimentally demonstrate a feasible integrated scheme to solve first-order linear ordinary differential equation with constant-coefficient tunable based on a single silicon microring resonator. Besides, we analyze the impact of the chirp and pulse-width of input signals on the computing deviation. This device can be compatible with the electronic technology (typically complementary metal-oxide semiconductor technology), which may motivate the development of integrated photonic circuits for optical computing.
Webcam-based flow cytometer using wide-field imaging for low cell number detection at high throughput
Authors: Balsam Joshua , Bruck Hugh Alan , Rasooly Avraham
Published: July 2014

Here we describe a novel low-cost high throughput flow cytometer based on a webcam capable of low cell number detection in a large volume which may overcome the limitations of current flow cytometry.
Simultaneous determination of eight active components in chloroform extracts from raw and vinegar-processed Genkwa flos using HPLC-MS and identification of the hepatotoxic ingredients with an HL-7702 cell
Authors: Zhang Yuanyuan , Zhang Ruowen , Yuan Yang , Geng Lulu , Zhao Xu , Meng Xia , Zhuang Hefei , Bi Kaishun , Chen Xiaohui
Published: July 2014

A method for quantitative analysis and identification of hepatotoxic substances on HL-7702 cells.
Self-assembly of random copolymers
Authors: Li Longyu , Raghupathi Kishore , Song Cunfeng , Prasad Priyaa , Thayumanavan S.
Published: July 2014

The versatility of random copolymer based self-assembly to provide diverse morphologies and their utility are discussed.
Self-assembled hierarchical yolk–shell structured NiO@C from metal–organic frameworks with outstanding performance for lithium storage
Authors: Liu Lixiang , Guo Hong , Liu Jiajia , Qian Fang , Zhang Conghai , Li Tingting , Chen Weiwei , Yang Xiangjun , Guo Yicheng
Published: July 2014

A facile strategy is employed to prepare hierarchical yolk–shell hybrid NiO@C materials via MOFs. The unique nanostructures as well as the hybrid characteristics of active components contribute greatly to the outstanding electrochemical performance.
Charge transfer (CT) mechanochromism: dramatic CT absorption change of crystalline π-conjugated oligomers containing TCNQ upon mechanical grinding
Authors: Nagai Atsushi , Okabe Yuki
Published: July 2014

New π-conjugated oligomers with high crystallinity were prepared from the simple solvothermal reaction of squaric acid and diaminopyrenes.
“Suspended” Pt nanoparticles over TiO2 nanotubes for enhanced photocatalytic H2 evolution
Authors: Nguyen Nhat Truong , Yoo JeongEun , Altomare Marco , Schmuki Patrik
Published: July 2014

In the present work we introduce a technique to form a photocatalyst based on minimal amounts of Pt nanoparticles suspended over the mouth of anodic TiO2 nanotubes.
Polymorphism and the influence of crystal structure on the luminescence of the opto-electronic material 4,4′-bis(9-carbazolyl)biphenyl
Authors: Gleason Cody J. , Cox Jordan M. , Walton Ian M. , Benedict Jason B.
Published: July 2014

Single crystal structures, luminescent properties and electronic structure calculations of three polymorphs of the opto-electronic charge transport material 4,4′-bis(9-carbazolyl)biphenyl.
Computational assignment of redox states to Coulomb blockade diamonds
Authors: Olsen Stine T. , Arcisauskaite Vaida , Hansen Thorsten , Kongsted Jacob , Mikkelsen Kurt V.
Published: July 2014

Our computational approach for constructing Coulomb blockade diamonds provides a powerful tool for interpreting molecular transistor experiments.
Cobalt orthosilicate as a new electrode material for secondary lithium-ion batteries
Authors: Mueller Franziska , Bresser Dominic , Minderjahn Nathalie , Kalhoff Julian , Menne Sebastian , Krueger Steffen , Winter Martin , Passerini Stefano
Published: July 2014

Co2SiO4 is investigated for the first time as lithium-ion active material and a lithium storage mechanism is proposed including the reversible formation of Li4SiO4.
Facile synthesis of novel MoS2@SnO2 hetero-nanoflowers and enhanced photocatalysis and field-emission properties
Authors: Li Jinzhu , Yu Ke , Tan Yinghua , Fu Hao , Zhang Qingfeng , Cong Weitao , Song Changqing , Yin Haihong , Zhu Ziqiang
Published: July 2014

A novel MoS2@SnO2 hetero-nanoflower was successfully synthesized by a facile hydrothermal method. The composite showed more excellent photocatalytic and field emission properties than that of MoS2.
Grazing incidence X-ray fluorescence of periodic structures – a comparison between X-ray standing waves and geometrical optics calculations
Authors: Reinhardt Falk , Nowak Stanisław H. , Beckhoff Burkhard , Dousse Jean-Claude , Schoengen Max
Published: July 2014

Geometrical optics calculations are able to reproduce experimentally found modulations in GIXRF which are beyond the potential of the XSW model.
Rapid, simultaneous separation of Sr, Pb, and Nd by extraction chromatography prior to isotope ratios determination by TIMS and MC-ICP-MS
Authors: Pin Christian , Gannoun Abdelmouhcine , Dupont Alain
Published: July 2014

A straightforward separation scheme is described for the separation of Sr, Pb, and Nd from silicate rocks.
GPCRserver: an accurate and novel G protein-coupled receptor predictor
Authors: Yan Renxiang , Wang Xiaofeng , Huang Lanqing , Lin Jun , Cai Weiwen , Zhang Ziding
Published: July 2014

G protein coupled receptors (GPCRs), also known as seven-transmembrane domain receptors, pass through the cellular membrane seven times and play diverse biological roles in the cells such as signaling, transporting of molecules and cell–cell communication.
Proximal gap-plasmon nanoresonators in the limit of vanishing inter-cavity separation
Authors: Tagliabue Giulia , Höller Christian , Eghlidi Hadi , Poulikakos Dimos
Published: July 2014

Gap-plasmon nanocavities exhibit negligible interaction even at vanishing inter-cavity separation. Upon electrical connection an abrupt change in the absorption spectrum occurs.
Probing the dendritic architecture through AIE: challenges and successes
Authors: Arseneault Mathieu , Leung Nelson L. C. , Fung Lai Tsz , Hu Rongrong , Morin Jean-François , Tang Ben Zhong
Published: July 2014

Since the aggregation-induced emission (AIE) phenomenon is very sensitive to steric hindrance, we set out to use it as a tool to probe the periphery of dendrimers.
Enhancement of tumor smart-targeting efficiency based on optical communication between signaling and receiving nanoparticles (modeling and analysis)
Authors: SalmanOgli Ahmad , Rostami Ali , Faranoush Mohammad , Dolatyari Mahbobeh , Rostami Ghassem
Published: July 2014

As far as we know, this is the first time optical communication between signaling and receiving nanoparticles has been analyzed and simulated for tumor smart-targeting.
Impact of serum proteins on MRI contrast agents: cellular binding and T2relaxation
Authors: Hill Alexandra , Payne Christine K.
Published: July 2014

Superparamagnetic iron oxide nanoparticles (SPIONs) used as MRI contrast agents or for theranostic applications encounter a complex mixture of extracellular proteins that adsorb on the SPION surface forming a protein corona.
Tunable field emission properties of well-aligned silicon nanowires with controlled aspect ratio and proximity
Authors: Lv Shasha , Li Zhengcao , Su Shiming , Lin Linhan , Zhang Zhengjun , Miao Wei
Published: July 2014

The FE properties were influenced by dimensionality and surface geometry structures, and improved with the increase of proximity.
Controllable geometry-mediated droplet fission using “off-the-shelf” capillary microfluidics device
Authors: Wang Yong , Wu Ping , Luo Zhaofeng , Li Yuting , Liao Meixiang , Li Yue , He Liqun
Published: July 2014

We describe a cheap, easily assembled, controllable droplet fission device to obtain a variety of uniform daughter droplets.
Enhanced photocatalytic properties of biomimetic Ag/AgCl heterostructures
Authors: Hu Hongyan , Jiao Zhengbo , Lu Gongxuan , Ye Jinhua , Bi Yingpu
Published: July 2014

Hierarchical Ag/AgCl hetero-structures have been fabricated in high-yield by copying the natural architecture of a branch with green leaves, and exhibit higher photocatalytic activities than Ag/AgCl nanowires, AgCl nanoparticles, Ag nanowires, and N-doped TiO2 for the degradation of organic contaminants under visible light irradiation.
Copper ferrite–graphene hybrid: a highly efficient magnetic catalyst for chemoselective reduction of nitroarenes
Authors: Zhang Haiyan , Gao Shutao , Shang Ningzhao , Wang Chun , Wang Zhi
Published: July 2014

In this paper, an inexpensive and magnetically recyclable copper ferrite–graphene hybrid nanocomposite was synthesized and used as an efficient catalyst for the reduction of nitroarenes for the first time.
Theoretical study on the structural, electronic and physical properties of layered alkaline-earth-group-4 transition-metal nitrides AEMN2
Authors: Orisakwe Esther , Fontaine Bruno , Gregory Duncan H. , Gautier Régis , Halet Jean-François
Published: July 2014

Thermodynamic, structural, and electronic properties of the layered ternary nitrides AEMN2 (AE = alkaline-earth; M = group 4 transition metal) both with the KCoO2 and α-NaFeO2 structure-types are examined within density-functional theory.
Trifluoromethylated nucleic acid analogues capable of self-assembly through hydrophobic interactions
Authors: Wang RuoWen , Wang Chunming , Cao Yang , Zhu Zhi , Yang Chaoyong , Chen Jianzhong , Qing Feng-Ling , Tan Weihong
Published: July 2014

An artificial nucleic acid analogue capable of self-assembly into a duplex merely through hydrophobic interactions is presented.
Active-template synthesis of “click” [2]rotaxane ligands: self-assembly of mechanically interlocked metallo-supramolecular dimers, macrocycles and oligomers
Authors: Noor Asif , Moratti Stephen C. , Crowley James D.
Published: July 2014

A "click" active-metal-template strategy has been exploited to develop mono- and bi-2,2′,6′,2″-terpyridine functionalised [2]rotaxanes. When reacted with Fe(ii) ions these rotaxanes formed metallo-bis-([2]rotaxanes), macrocycles and oligomers.
Thermodynamic and kinetic assessments of strontium-doped lanthanum manganite perovskites for two-step thermochemical water splitting
Authors: Yang Chih-Kai , Yamazaki Yoshihiro , Aydin Aykut , Haile Sossina M.
Published: July 2014

Hydrogen production increases with increasing Sr content, but at a kinetic penalty; intermediate Sr levels are advantageous for solar thermochemical fuel production.
Free-standing three-dimensional graphene and polyaniline nanowire arrays hybrid foams for high-performance flexible and lightweight supercapacitors
Authors: Yu Pingping , Zhao Xin , Huang Zilong , Li Yingzhi , Zhang Qinghua
Published: July 2014

Free-standing three-dimensional hierarchical porous reduced graphene oxide foam (RGO-F) was first fabricated by a “dipping and dry” method using nickel foam as a template.
Mapping smooth profile H‐plane rectangular waveguide structures to substrate integrated waveguide technology
Authors: Diaz Caballero E. , Roldan I. , Urrea V. , Chudzik M. , Arregui I. , Arnedo I. , Belenguer A.
Published: July 2014

The guidelines for mapping rectangular waveguide structures to substrate integrated waveguide (SIW) technology are well understood for structures with straight walls. However, the mapping of a smooth profile structure from rectangular waveguide to SIW technology is not trivial and it needs to be carefully studied. A general procedure for mapping any smooth profile H‐plane rectangular waveguide structure to SIW technology is proposed. A practical example is also provided and experimentally validated.
Energy‐efficient multi‐standard early stopping criterion for low‐density‐parity‐check iterative decoding
Authors: Condo Carlo , Baghdadi Amer , Masera Guido
Published: July 2014

Low‐density‐parity‐check codes decoding relies on powerful iterative algorithms, whose implementation is often expensive in terms of complexity and power consumption. Several early stopping criteria (ESCs) have been proposed to reduce the number of iterations performed by a decoder with no (or limited) degradation of error correction performance. However, most of the existing ESCs have considered a reduced set of system parameters for validation and often have ignored the impacts related to a real hardware implementation. This study proposes a novel multi‐standard early stopping criterion (MSESC) able to adapt dynamically to changes of code parameters, quantisation and channel conditions. A dedicated hardware architecture is devised and integrated in a multi‐standard decoder, and compared with existing techniques. Post‐layout results of the proposed MSESC show a small area increment (+1.3%) and a large decrement of the average energy consumption (up to 87.2%) with respect to the same decoder implemented with no ESC. Moreover, it is shown that MSESC offers an energy consumption reduction with respect to the state‐of‐the‐art ESCs ranging from 4% [at high signal‐to‐noise ratio (SNR)] to 16% (at low SNR).
Cryptanalysis of countermeasures against multiple transmission attacks on NTRU
Authors: Xu Jun , Hu Lei , Sun Siwei , Xie Yonghong
Published: July 2014

The original Number Theory Research Unit (NTRU) public key cryptosystem is vulnerable to multiple transmission attacks, and the designers of NTRU presented two countermeasures to prevent such attacks. In this study, the authors show that the first countermeasure is still not secure, the plaintext can be revealed by a linearisation attack technique. Moreover, they demonstrate that the first countermeasure is even not secure for broadcast attacks, a class of more general attacks than multiple transmission attacks. For the second countermeasure, they show that one special case of its padding function for the plaintext is also insecure and the original plaintext can be obtained by lattice methods.
Mixed L− /L1 fault detection filter design for fuzzy positive linear systems with time‐varying delays
Authors: Huang Shipei , Xiang Zhengrong , Karimi Hamid Reza
Published: July 2014

This study investigates the problem of fault detection for a class of fuzzy positive systems with time‐varying delays. A new fault sensitivity measure, called L− index, is proposed. The L− fault detection filter design and multiobjective L− /L1 fault detection filter design problems are addressed. A co‐positive type Lyapunov–Krasovskii functional is constructed for the performance analysis and fault detection filter design. Sufficient conditions for the existence of such two filers are firstly given, and then the design methods are presented. Finally, two examples are provided to show the effectiveness and applicability of the proposed method.
Pinning observability in complex networks
Authors: Yu Wenwu , Wen Guanghui , Lü Jinhu , Yu Xinghuo
Published: July 2014

A new concept called pinning observability for complex networks is first proposed in this study. It is well known that in a very large‐scale network, there are many nodes as well as lots of connections among the nodes. Thus, it is literally impossible to observe states of all the nodes so as to recover the network by reaching synchronisation between the original network and a newly constructed network. To reduce the number of observable nodes’ states, some feedback controllers can be applied on a small fraction of the chosen nodes to realise the synchronisation. Hence, the new concept pinning observability in complex networks is introduced for this purpose. First, a general criterion for synchronisation via pinning observability in complex networks with linear coupling is given based on which the parametric regions for pinning observability are discussed. Then, some decoupled and easily verified conditions for pinning observability are derived. Furthermore, a general criterion for synchronisation via pinning observability in complex networks with non‐linear coupling is given and an application to genetic regulatory networks via pinning observability is formulated. Finally, some simulation examples are given to verify the present theoretical analysis in this study.
Time‐varying formation control for high‐order linear swarm systems with switching interaction topologies
Authors: Dong Xiwang , Shi Zongying , Lu Geng , Zhong Yisheng
Published: July 2014

Time‐varying formation control problems for high‐order linear time‐invariant swarm systems with switching interaction topologies are investigated. A general formation control protocol is proposed firstly. Then using a consensus based approach, necessary and sufficient conditions for swarm systems with switching interaction topologies to achieve a given time‐varying formation are presented. An explicit expression of the time‐varying formation reference function is given. It is revealed that the switching interaction topologies have no effect on the formation reference function and the motion modes of the formation reference can be specified. Furthermore, necessary and sufficient conditions for formation feasibility are presented. An approach to expand the feasible formation set is given and an algorithm to design the protocol for swarm systems with switching interaction topologies to achieve time‐varying formations is provided. Finally, numerical simulations are presented to demonstrate theoretical results.
Synchronisation of linear continuous multi‐agent systems with switching topology and communication delay
Authors: Xiang Ji , Li Yanjun , Wei Wei , Yang Taicheng
Published: July 2014

A distributed dynamic output feedback control is designed by Scardovi and Sepulchre for the synchronisation of a network of identical linear systems, known as agents in literature. The design is based on some mild conditions allowing switching topology. However, it assumes that there is no time delay in signal transfer between the neighbouring agents. In this study, the authors extend their work to include known time delay in communications. Furthermore, the authors’ design has some special features: (i) the delay can be arbitrary and only need to be uniformly bounded by a constant; (ii) the conditions that time delay should be the same and sufficiently small in some literature are not required here; and (iii) no local buffer is required to store past data because of time‐delay effect.
Simultaneous robust actuator and sensor fault estimation for uncertain non‐linear Lipschitz systems
Authors: Zhang Jian , Swain Akshya Kumar , Nguang Sing Kiong
Published: July 2014

The present study proposes two schemes for simultaneously estimating actuator and sensor faults for a class of uncertain non‐linear systems. In the first scheme, two sliding mode observers (SMOs) are designed to estimate actuator and sensor faults, respectively, under the assumption that the matching condition holds. In the second scheme, the assumption of matching condition is relaxed and an adaptive observer has been designed to estimate the sensor fault instead of using an SMO. The effects of the system uncertainties on the estimation errors of states and faults are reduced by integrating a prescribed ℋ∞ disturbance attenuation level into the proposed schemes. The sufficient condition for the existence of the proposed observers with ℋ∞ tracking performance is derived and expressed as a linear matrix inequality optimisation problem such that the ℒ2 gain between the estimation errors and system uncertainties is minimised. Finally, a simulation study is presented to illustrate the effectiveness of the proposed schemes.
Exponential stability of impulsive positive systems with mixed time‐varying delays
Authors: Wang Yan‐Wu , Zhang Ji‐Shi , Liu Meng
Published: July 2014

This study addresses the problem of exponential stability for a class of impulsive positive systems with mixed time‐varying delays. A delayed impulsive positive system model is introduced for the first time and a necessary and sufficient condition guaranteeing the positivity of this kind of system is proposed. By using a copositive Lyapunov–Krasovskii functional and the average impulsive interval method, a sufficient criterion of global exponential stability for delayed impulsive positive systems is established in terms of linear programming problems. A numerical example is given to show the effectiveness of the proposed method.
High step‐up passive absorption circuit used in non‐isolated high step‐up converter
Authors: Hu Yihua , Deng Yan , Long Jiangtao , Lu Xiaoxun
Published: July 2014

To obtain a high step‐up gain with high efficiency in distributed power sources application, such as photovoltaic (PV) and fuel cells, a passive absorption circuit with voltage step‐up character is inserted in the interleaved flyback‐forward converter for leakage energy recycle and voltage gain extension. By applying the high step‐up passive‐clamp circuit, the voltage spike on the metal‐oxide semiconductor field‐effect transistor is clamped and the energy stored inside the leakage inductance of the coupled inductor can be recycled to get high‐output voltage. Moreover, it offers another design freedom to obtain higher voltage‐conversion ratio. The operational principle and characteristics of the improved flyback‐forward converter are presented, and verified experimentally with a 500 W prototype converter. The proposed high step‐up passive‐clamp can be widely used in high step‐up DC–DC converter applications, and a new high step‐up topology is deduced to illustrate the theoretical analysis.
Single‐phase phase locked loop with DC offset and noise rejection for photovoltaic inverters
Authors: Lubura Slobodan , Šoja Milomir , Lale Srd‐an , Ikić Marko
Published: July 2014

Proper work of grid‐connected converters requires an accurate detection of phase angle, frequency and amplitude of grid voltage. Phase locked loops (PLLs) based on synchronous reference frame theory can be used for estimation of these grid parameters. One of the issues that could appear during estimation of grid parameters is appearance of DC offset in measured grid voltage. This DC component (offset) is usually entered in PLL structure via measurement and A/D conversion process. Undesirable induced DC offset could appear as part of the reference sine current of photovoltaic inverters or other grid‐connected converters. A lot of standards define allowed PV inverter's DC current injection in the grid. In this study, we propose an improved PLL structure with capability to fully reject DC offset and noise which could appear in measured input grid voltage. The key component of the proposed PLL is two‐phase generator with a closed control loop for DC offset and noise rejection. Obtained simulation and experimental results show that the proposed PLL structure can solve important issues of presence of noise and DC offset in measured grid voltage. The proposed PLL structure shows excellent dynamical performances in conditions of fast changes of grid parameters.
DC converter with three circuit cells – analysis, design and experimental evaluation
Authors: Lin Bor‐Ren , Liao Jian‐Ting , Chao Chia‐Hung
Published: July 2014

A new DC/DC converter with three circuit cells has been presented. For high input voltage applications, two‐input split capacitors with four active switches are used in the proposed converter to limit the voltage stress of each power switch at one‐half of input voltage. Thus, power metal‐oxide semiconductor field‐effect transistors (MOSFETs) with 500 V voltage rating can be adopted for 1000 V input voltage applications. Two balance capacitors are adopted in the proposed circuit to automatically balance two split input capacitor voltages in each switching cycle. Three resonant tanks are used at primary side of the proposed converter to share the load current and reduce the current stress of passive components. Thus, the sizes of the magnetic core and bobbin are reduced. If the operating switching frequency is less than the series resonant frequency, power MOSFETs are turned on at zero‐voltage switching and rectifier diodes can be turned off at zero current switching. Thus, the switching losses on power semiconductors are reduced. Finally, experiments with a 1.5 kW prototype are provided to verify the effectiveness of the proposed converter.
DC–DC converter with high voltage gain and reduced switch stress
Authors: Chen Yie‐Tone , Tsai Ming‐Hsiu , Liang Ruey‐Hsun
Published: July 2014

In this study, a novel high step‐up dc–dc converter with high voltage gain and reduced switch stress is proposed. Utilising the coupled inductor to replace the boost inductor for high step‐up converter is widely used in the application of high voltage gain converter. It can not only achieve a high voltage gain but also use the core effectively by using the coupled inductor. The techniques of voltage lift, voltage multiplier and clamp mode are also used in the proposed topology. Furthermore, the proposed converter can avoid the extreme duty cycle that will cause a lot of conduction losses. The leakage inductance energy of the coupled inductor will cause a huge voltage on the components of circuit, so that it needs to choose the components with high voltage and current ratings; then the efficiency is reduced and the cost is increased. The converter proposed in this paper can not only recycle the leakage inductance energy to the output but also increase the efficiency. A 300 W prototype converter which is implemented with an input voltage of 26 V and an output voltage of 400 V will demonstrate the effectiveness of this proposed converter.
Ad‐hoc analytical solution based on local linearisations for doubly‐fed induction generator wind turbine electromechanical simulations
Authors: Cañas‐Carretón Miguel , Gómez‐Lázaro Emilio , Amat‐Plata Sergio , Molina‐García Ángel
Published: July 2014

This study presents a new methodology to solve the wind turbine modelling based on doubly‐fed induction generator (DFIG) technology. The proposed solution allows us to simulate simultaneously a significant number of individuals DFIG submitted to different wind‐speed profiles, minimising the computational time costs and avoiding excessive simplifications in comparison with previous solutions. For this proposal, a third‐order induction generator model has been considered by the authors. The rotor current‐control loops have been modelled through standard PI regulators, discussing in detail rotor voltage expressions and values of the parameters. The global non‐linear equation system has been rearranged in state‐space forms, by means of local linearisations and using two different software‐packages that enable symbolic computation in a collaborative manner. The analytical results have been compared facing a traditional discretised solving methodology to assess the suitability of the proposed solution under different wind‐speed conditions. Indeed, simulated and real‐measured wind profiles have been considered for this purpose. Finally, a comparison of computational time costs for different time steps, including the effect of the number of wind turbines, is also included in this study.
Novel modular and retractable permanent magnet motor/generator for flywheel applications with reduced iron losses in stand‐by mode
Authors: García‐Gracia Miguel , Cova Miguel Angel , Villen Maria Teresa , Uson Antonio
Published: July 2014

The no‐load losses represent one of the most important problems for flywheels energy storage systems (FESS) which produce electrical energy from the kinetic energy stored with long waiting times between charging and discharging. This study presents a novel modular stator for use in synchronous permanent magnet (PM) electrical machine coupled to a FESS. The modular stator includes several sections of retractable yoke stator, displaceable in the radial direction. Each stator segment is composed of several coils, teeth and its corresponding back iron section. A removable back iron yoke stator allows reducing the iron losses in the ferromagnetic core of the PM motor/generator during stand‐by operation mode in FESS. In stand‐by mode, with the stator in a retracted position, the iron losses are reduced up to 95% when the air gap length is increased 20 mm.
Possible energy gain for a plasma-liner-driven magneto-inertial fusion concept
Authors: Knapp C. E. , Kirkpatrick R. C.
Published: July 2014

A one-dimensional parameter study of a Magneto-Inertial Fusion (MIF) concept indicates that significant gain may be achievable. This concept uses a dynamically formed plasma shell with inwardly directed momentum to drive a magnetized fuel to ignition, which in turn partially burns an intermediate layer of unmagnetized fuel. The concept is referred to as Plasma Jet MIF or PJMIF. The results of an adaptive mesh refinement Eulerian code (Crestone) are compared to those of a Lagrangian code (LASNEX). These are the first published results using the Crestone and LASNEX codes on the PJMIF concept.
Properties of reactive oxygen species by quantum Monte Carlo
Authors: Zen Andrea , Trout Bernhardt L. , Guidoni Leonardo
Published: July 2014

The electronic properties of the oxygen molecule, in its singlet and triplet states, and of many small oxygen-containing radicals and anions have important roles in different fields of chemistry, biology, and atmospheric science. Nevertheless, the electronic structure of such species is a challenge for ab initio computational approaches because of the difficulties to correctly describe the statical and dynamical correlation effects in presence of one or more unpaired electrons. Only the highest-level quantum chemical approaches can yield reliable characterizations of their molecular properties, such as binding energies, equilibrium structures, molecular vibrations, charge distribution, and polarizabilities. In this work we use the variational Monte Carlo (VMC) and the lattice regularized Monte Carlo (LRDMC) methods to investigate the equilibrium geometries and molecular properties of oxygen and oxygen reactive species. Quantum Monte Carlo methods are used in combination with the Jastrow Antisymmetrized Geminal Power (JAGP) wave function ansatz, which has been recently shown to effectively describe the statical and dynamical correlation of different molecular systems. In particular, we have studied the oxygen molecule, the superoxide anion, the nitric oxide radical and anion, the hydroxyl and hydroperoxyl radicals and their corresponding anions, and the hydrotrioxyl radical. Overall, the methodology was able to correctly describe the geometrical and electronic properties of these systems, through compact but fully-optimised basis sets and with a computational cost which scales as N3 − N4, where N is the number of electrons. This work is therefore opening the way to the accurate study of the energetics and of the reactivity of large and complex oxygen species by first principles.
Revisiting the relaxation dynamics of isolated pyrrole
Authors: Montero Raúl , Ovejas Virginia , Fernández-Fernández Marta , Peralta Conde Álvaro , Longarte Asier
Published: July 2014

Herein, the interpretation of the femtosecond-scale temporal evolution of the pyrrole ion signal, after excitation in the 267–217 nm interval, recently published by our group [R. Montero, A. Peralta Conde, V. Ovejas, M. Fernández-Fernández, F. Castaño, J. R. Vázquez de Aldana, and A. Longarte, J. Chem. Phys. 137, 064317 (2012)] is re-visited. The observation of a shift in the pyrrole+ transient respect to zero delay reference, initially attributed to ultrafast dynamics on the πσ* type state (3s a1 ← π 1a2), is demonstrated to be caused by the existence of pump + probe populated states, along the ionization process. The influence of these resonances in pump-prone ionization experiments, when multi-photon probes are used, and the significance of a proper zero-time reference, is discussed. The possibility of preparing the πσ* state by direct excitation is investigated by collecting 1 + 1 photoelectron spectra, at excitation wavelengths ranging from 255 to 219 nm. No conclusive evidences of ionization through this state are found.
Effect of point and grain boundary defects on the mechanical behavior of monolayer MoS2 under tension via atomistic simulations
Authors: Dang Khanh Q. , Spearot Douglas E.
Published: July 2014

Atomistic simulation is used to study the structure and energy of defects in monolayer MoS2 and the role of defects on the mechanical properties of monolayer MoS2. First, energy minimization is used to study the structure and energy of monosulfur vacancies positioned within the bottom S layer of the MoS2 lattice, and 60° symmetric tilt grain boundaries along the zigzag and armchair directions, with comparison to experimental observations and density functional theory calculations. Second, molecular dynamics simulations are used to subject suspended defect-containing MoS2 membranes to a state of multiaxial tension. A phase transformation is observed in the defect-containing membranes, similar to prior work in the literature. For monolayer MoS2 membranes with point defects, groups of monosulfur vacancies promote stress-concentration points, allowing failure to initiate away from the center of the membrane. For monolayer MoS2 membranes with grain boundaries, failure initiates at the grain boundary and it is found that the breaking force for the membrane is independent of grain boundary energy.
Graphene oxide catalyzed cis-trans isomerization of azobenzene
Authors: Shin Dongha , Kang Jin Hyoun , Min Kyung-Ah , Hong Suklyun , Hee Hong Byung
Published: July 2014

We report the fast cis-trans isomerization of an amine-substituted azobenzene catalyzed by graphene oxide (GO), where the amine functionality facilitates the charge transfer from azobenzene to graphene oxide in contrast to non-substituted azobenzene. This catalytic effect was not observed in stilbene analogues, which strongly supports the existence of different isomerization pathways between azobenzene and stilbene. The graphene oxide catalyzed isomerization is expected to be useful as a new photoisomerization based sensing platform complementary to GO-based fluorescence quenching methods.
The enhanced performances of a high-temperature superconducting fractal and meander delay line
Authors: Wang Rui-Xia , Wei Bin , Cao Bi-Song , Guo Xu-Bo , Song Fei , Jiang Li-Nan
Published: July 2014

This paper presents a compact fractal and meander delay line. The introduced fractal and meander microstructure results in remarkably increase in delay time. The proposed asymmetrical microstructures show shielding effects, leading to a much weaker forward coupling between adjacent fractal and meander delay lines. The weakened forward coupling brings about a compact size and small return loss. A fractal and meander delay line is fabricated with high-temperature superconducting thin films and measured at 75 K, which achieved extremely low insertion loss. The measured results are consistent with simulation results.
Early Development of Dynamic Shape Perception under Slit-Viewing Conditions
Authors: Imura Tomoko , Shirai Nobu
Published: July 2014

The developmental processes underpinning global shape and global motion perception in infancy have been relatively well described. However, the development of the ability to integrate both global motion and global shape information has remained unclear. In this study we employed a slit-viewing task to investigate the ability to integrate spatiotemporal information among infants ranging in age from 3 to 12 months. In experiment 1 each infant was familiarised with a moving object that was only partly visible through a slit. One of the two objects in the test trial was a novel object, and the other object had appeared previously in familiarisation trials. The findings suggested that infants aged 5 months and over looked longer at the novel drawings compared with the more familiar objects in the test trials. This implies that the infants recognised the whole shape of the object under the slit-viewing condition. In experiment 2 each infant was presented with partial images in a random order. In this case the infants were unable to distinguish the whole shape of the object. The findings suggest that infants did not rely on the local cues provided in experiment 1.
Long-Term Abacus Training Induces Automatic Processing of Abacus Numbers in Children
Authors: Du Fenglei , Yao Yuan , Zhang Qiong , Chen Feiyan
Published: July 2014

Abacus-based mental calculation (AMC) is a unique strategy for arithmetic that is based on the mental abacus. AMC experts can solve calculation problems with extraordinarily fast speed and high accuracy. Previous studies have demonstrated that abacus experts showed superior performance and special neural correlates during numerical tasks. However, most of those studies focused on the perception and cognition of Arabic numbers. It remains unclear how the abacus numbers were perceived. By applying a similar enumeration Stroop task, in which participants are presented with a visual display containing two abacus numbers and asked to compare the numerosity of beads that consisted of the abacus number, in the present study we investigated the automatic processing of the numerical value of abacus numbers in abacus-trained children. The results demonstrated a significant congruity effect in the numerosity comparison task for abacus-trained children, in both reaction time and error rate analysis. These results suggested that the numerical value of abacus numbers was perceived automatically by the abacus-trained children after long-term training.
Vection is Modulated by the Semantic Meaning of Stimuli and Experimental Instructions
Authors: Ogawa Masaki , Seno Takeharu
Published: July 2014

Vection strength is modulated by the semantic meanings of stimuli. In experiment 1—even though vection stimuli were of uniform size, color, and luminance—when they also had semantic meaning as falling objects, vection was inhibited. Specifically, stimuli perceived as feathers, petals, and leaves did not effectively induce vection. In experiment 2 we used the downward motion of identical dots to induce vection. Participants observed stimuli while holding either an umbrella or a wooden sword. Results showed that vection was inhibited when participants held the umbrella and the stimuli was perceived as rain or snow falling. The two experiments suggest that vection is modulated by the semantic meaning of stimuli.
Genetic variability and identification of quantitative trait loci affecting plant growth and chlorophyll fluorescence parameters in the model legume Medicago truncatula under control and salt stress conditions
Authors: Exbrayat Sarah , Bertoni Georges , Naghavie Mohamad Reza , Peyghambari Ali , Badri Mounavar , Debelle Frédéric
Published: July 2014

Salinity is one of the major stresses that limits crop production worldwide and affects most physiological activities in plants. In order to study the genetic control of salt stress in the model legume Medicago truncatula Gaertn., an experiment was undertaken to determine the genetic variability and to identify quantitative trait loci (QTLs) controlling several traits related to plant growth and physiology in a population of recombinant inbred lines. Shoot and root DW, relative water content, leaf area, chlorophyll content, chlorophyll fluorescence parameters, and Na+ and K+ in shoots and roots were measured. The experiment was carried out with three replications. ANOVA showed a large genetic variation and transgressive segregation for the traits studied, suggesting putative complex tolerance mechanisms. A total of 21 QTLs were detected under control conditions and 19 QTLs were identified under 100 mm salt stress conditions, with three QTLs being common to both situations. The percentage of total phenotypic variance explained by the QTLs ranged from 4.6% to 23.01%. Overlapping QTLs for different traits were also observed, which enables us to discriminate independent traits from linked ones. The results should be helpful information for further functional analysis of salt tolerance in M. truncatula.
Russian feminist perspectives on Pussy Riot
Authors: Sperling Valerie
Published: July 2014

While Pussy Riot's “Punk Prayer” and its aftermath constituted something of a turning point for Russia politically - as well as personally for the women imprisoned afterwards - it was neither the first nor last of Pussy Riot's endeavors. Among other things, their series of songs, published as video clips on the web, endorsed mass protest against the Putin regime, criticized state-sponsored homophobia, and praised feminism as a possible curative for Russia's many ills. In setting forth their ideas, however, Pussy Riot's lyricists made use of traditional masculine and feminine gender norms as well as homophobia, wielding these against their opponents in the regime and thereby reinforcing them in ways that other self-identified Russian feminists found problematic at best.

In this article, I review Pussy Riot's collection of songs in chronological order, highlighting the areas where gender norms and apparent misogyny, sexism, and homophobia appear. I weave my explications of the content of Pussy Riot's productions in with the responses of Russian feminist activists to Pussy Riot's lyrics and actions. Taking into account the views of some non-feminist Russian commentators in addition to self-identified feminist activists, I discuss a range of evaluations of the content of Pussy Riot's compositions, as well as differing appraisals of the means that Pussy Riot employed to achieve what they viewed as feminist ends: undermining or even unseating the Putin regime.
Practice‐based research networks: Origins, overview, obstacles, and opportunities
Authors: Barkham Michael
Published: July 2014

Aims: This article focuses on the historical origins of Practice‐based Research Networks (PbRNs), particularly in the UK, and provides an overview of exemplar networks, together with a consideration of the obstacles and opportunities of such networks. Method: A selective narrative review was carried out relating to the origins of PbRNs together with a selective systematic review using the SCOPUS database to consider landmark articles in this field. Results: A historical account is provided with the origins of PbRNs deriving from pioneer GPs working alone, with their ideals then becoming embedded in family practice. Key articles are presented and also consideration given to the threats to their survival. Conceptual and developmental models of PbRNs are presented that reflect the variety of networks but also common hallmarks. Finally, the opportunities are summarised that PbRNs offer for providing a vehicle for research that is linked more closely to communities of practitioners, people, and patients. Conclusions: PbRNs provide the opportunities for including practitioners in the research effort by being part of a community. Results will have direct relevance to their practice and advances in data analysis provide more valid means of analysing data. But there are also continuing threats due to lack of infrastructure funding and a gap between PbRN activity and trials methodology that needs to be addressed.
Sleep/wake behaviours of elite athletes from individual and team sports
Authors: Lastella Michele , Roach Gregory D. , Halson Shona L. , Sargent Charli
Published: July 2014

Sleep is an essential component for athlete recovery due to its physiological and psychological restorative effects, yet few studies have explored the habitual sleep/wake behaviour of elite athletes. The aims of the present study were to investigate the habitual sleep/wake behaviour of elite athletes, and to compare the differences in sleep between athletes from individual and team sports. A total of 124 (104 male, 20 female) elite athletes (mean ± s: age 22.2 ± 3.0 years) from five individual sports and four team sports participated in this study. Participants' sleep/wake behaviour was assessed using self‐report sleep diaries and wrist activity monitors for a minimum of seven nights (range 7–28 nights) during a typical training phase. Mixed‐effects analyses of variances were conducted to compare the differences in the sleep/wake behaviour of athletes from two sport types (i.e. individual and team). Overall, this sample of athletes went to bed at 22:59 ± 1.3, woke up at 07:15 ± 1.2 and obtained 6.8 ± 1.1 h of sleep per night. Athletes from individual sports went to bed earlier, woke up earlier and obtained less sleep (individual vs team; 6.5 vs 7.0 h) than athletes from team sports. These data indicate that athletes obtain well below the recommended 8 h of sleep per night, with shorter sleep durations existing among athletes from individual sports.
Numerical Solution of the Spin-1 Heisenberg Antiferromagnetic Chains by Using a Projector Method
Authors: Sun Gang
Published: July 2014

An efficient projector Monte Carlo method has been used to calculate the energies of the ground state and the first excited state, and hence the gap between them, of the spin-1 Heisenberg antiferromagnetic chains with linear sizes up to

. We have computed them on chains up to

. We have found that the size-dependence of the ground state energy per site has the form

, which implies that there is a gap between the ground state and the first excited state. The value of the ground state energy per site as

is

. The direct extrapolation of

also shows that a gap of

exists as

.