bluuebunny/crossref_metadata_2025 huggingface dataset:
Knockout of NMDA-receptors from parvalbumin interneurons sensitizes to schizophrenia-related deficits induced by MK-801
Authors: Bygrave A M , Masiulis S , Nicholson E , Berkemann M , Barkus C , Sprengel R , Harrison P J , Kullmann D M , Bannerman D M , Kätzel D
Published: April 2016

It has been suggested that a functional deficit in NMDA-receptors (NMDARs) on parvalbumin (PV)-positive interneurons (PV-NMDARs) is central to the pathophysiology of schizophrenia. Supportive evidence come from examination of genetically modified mice where the obligatory NMDAR-subunit GluN1 (also known as NR1) has been deleted from PV interneurons by Cre-mediated knockout of the corresponding gene Grin1 (Grin1ΔPV mice). Notably, such PV-specific GluN1 ablation has been reported to blunt the induction of hyperlocomotion (a surrogate for psychosis) by pharmacological NMDAR blockade with the non-competitive antagonist MK-801. This suggests PV-NMDARs as the site of the psychosis-inducing action of MK-801. In contrast to this hypothesis, we show here that Grin1ΔPV mice are not protected against the effects of MK-801, but are in fact sensitized to many of them. Compared with control animals, Grin1ΔPVmice injected with MK-801 show increased stereotypy and pronounced catalepsy, which confound the locomotor readout. Furthermore, in Grin1ΔPVmice, MK-801 induced medial-prefrontal delta (4 Hz) oscillations, and impaired performance on tests of motor coordination, working memory and sucrose preference, even at lower doses than in wild-type controls. We also found that untreated Grin1ΔPVmice are largely normal across a wide range of cognitive functions, including attention, cognitive flexibility and various forms of short-term memory. Taken together these results argue against PV-specific NMDAR hypofunction as a key starting point of schizophrenia pathophysiology, but support a model where NMDAR hypofunction in multiple cell types contribute to the disease.
Conceptual design of tetraazaporphyrin- and subtetraazaporphyrin-based functional nanocarbon materials: electronic structures, topologies, optical properties, and methane storage capacities
Authors: Belosludov Rodion V. , Rhoda Hannah M. , Zhdanov Ravil K. , Belosludov Vladimir R. , Kawazoe Yoshiyuki , Nemykin Victor N.
Published: April 2016

A conceptual design of the three- and four-fold tetraazaporphyrin- and sutetraazaporphyrin-based functional 3D nanocage and nanobarrel structures have been proposed on the basis of DFT, TDDFT, and MD calculations.
Chronic addition of a common engineered nanomaterial alters biomass, activity and composition of stream biofilm communities
Authors: Binh Chu Thi Thanh , Adams Erin , Vigen Erika , Tong Tiezheng , Alsina Marco A. , Gaillard Jean-François , Gray Kimberly A. , Peterson Christopher G. , Kelly John J.
Published: April 2016

We report that chronic addition of a low-concentration of nano-TiO2to model streams reduced biofilm-associated microbial abundance and activity.
Identification of sulphur in nail polish by pattern recognition methods combined with portable energy dispersive X-ray fluorescence spectral data
Authors: Melquiades Fábio L. , Alves da Silva Alanna Mattos
Published: April 2016

Green analytical method for inspection and quality assurance of nail polish.
Z-effect reversal in carboxylic acid associates
Authors: Medvedev Michael G. , Bushmarinov Ivan S. , Lyssenko Konstantin A.
Published: April 2016

The conformational preferences of carboxylic acids (Z-effect) can be reversed by H-bonding to anions due to the supramolecular stereoelectronic effect.
Olefin hydrosilylation catalyzed by cationic nickel(ii) allyl complexes: a non-innocent allyl ligand-assisted mechanism
Authors: Mathew J. , Nakajima Y. , Choe Y.-K. , Urabe Y. , Ando W. , Sato K. , Shimada S.
Published: April 2016

Cationic nickel allyl complexes catalyse selective monohydrosilylation of α-olefins with sec-silanes via a unique mechanism assisted by a non-innocent allyl ligand.
Effects of a TiC substrate on the catalytic activity of Pt for NO reduction
Authors: Chu Xingli , Fu Zhaoming , Li Shasha , Zhang Xilin , Yang Zongxian
Published: April 2016

The catalytic properties of a Pt monolayer supported on a TiC(001) substrate (Pt/TiC) toward NO reduction.
High-field dissolution dynamic nuclear polarization of [1-13C]pyruvic acid
Authors: Yoshihara Hikari A. I. , Can Emine , Karlsson Magnus , Lerche Mathilde H. , Schwitter Juerg , Comment Arnaud
Published: April 2016

Greater than 60% solution-state polarization of [1-13C]pyruvic acid polarized at 7 T and 1.0 K can be measured after rapid transfer to an MRI scanner magnet.
Tight binding model of conformational disorder effects on the optical absorption spectrum of polythiophenes
Authors: Bombile Joel H. , Janik Michael J. , Milner Scott T.
Published: April 2016

A cost effective model that effectively reproduces the effect of dihedral rotations on the valence and conduction bands of polythiophenes.
Electrochemical and in situ X-ray spectroscopic studies of MnO2/reduced graphene oxide nanocomposites as a supercapacitor
Authors: Chang Han-Wei , Lu Ying-Rui , Chen Jeng-Lung , Chen Chi-Liang , Lee Jyh-Fu , Chen Jin-Ming , Tsai Yu-Chen , Yeh Ping-Hung , Chou Wu Ching , Dong Chung-Li
Published: April 2016

An in situ XAS investigation reveals charge–discharge mechanisms of MnO2/carbon-based materials.
A van der Waals density functional investigation of carboranethiol self-assembled monolayers on Au(111)
Authors: Mete Ersen , Yılmaz Ayşen , Danışman Mehmet Fatih
Published: April 2016

Isolated and full monolayer adsorption of various carboranethiol (C2B10H12S) isomers on the gold(111) surface has been investigated using both the standard and van der Waals density functional theory calculations.
Rutile titanium dioxide prepared by hydrogen reduction of Degussa P25 for highly efficient photocatalytic hydrogen evolution
Authors: Amano Fumiaki , Nakata Masashi , Yamamoto Akira , Tanaka Tsunehiro
Published: April 2016

The quantum efficiency of reduced TiO2 was 46% under 390 nm irradiation, which was much higher than that of Degussa P25.
Effect of the Cα substitution on the ketonic decarboxylation of carboxylic acids over m-ZrO2: the role of entropy
Authors: Oliver-Tomas B. , Gonell F. , Pulido A. , Renz M. , Boronat M.
Published: April 2016

Entropy effects and not activation energies are responsible for the lower reactivity of branched acids towards ZrO2-catalyzed ketonic decarboxylation.
Syntheses, structures and anti-tumor activity of four new organotin(iv) carboxylates based on 2-thienylselenoacetic acid
Authors: Zhang Yuan-Yuan , Zhang Ru-Fen , Zhang Shao-Liang , Cheng Shuang , Li Qian-Li , Ma Chun-Lin
Published: April 2016

With the 2-thienylselenoacetic acid ligand, four new organotin complexes have been synthesized and characterized by X-ray crystallography, elemental analysis, FT-IR and NMR (1H,13C, and119Sn) spectroscopy.
Emerging investigators series: virus mitigation by coagulation: recent discoveries and future directions
Authors: Heffron Joe , Mayer Brooke K.
Published: April 2016

Forces influencing virion sorption and recent findings of coagulation-based inactivation inform new research directions for mitigating waterborne viruses by coagulation.
In situ studies of materials for high temperature CO2capture and storage
Authors: Dunstan Matthew T. , Maugeri Serena A. , Liu Wen , Tucker Matthew G. , Taiwo Oluwadamilola O. , Gonzalez Belen , Allan Phoebe K. , Gaultois Michael W. , Shearing Paul R. , Keen David A. , Phillips Anthony E. , Dove Martin T. , Scott Stuart A. , Dennis John S. , Grey Clare P.
Published: April 2016

Carbon capture and storage (CCS) offers a possible solution to curb the CO2emissions from stationary sources in the coming decades, considering the delays in shifting energy generation to carbon neutral sources such as wind, solar and biomass. The most mature technology for post-combustion capture uses a liquid sorbent, amine scrubbing. However, with the existing technology, a large amount of heat is required for the regeneration of the liquid sorbent, which introduces a substantial energy penalty. The use of alternative sorbents for CO2capture, such as the CaO–CaCO3system, has been investigated extensively in recent years. However there are significant problems associated with the use of CaO based sorbents, the most challenging one being the deactivation of the sorbent material. When sorbents such as natural limestone are used, the capture capacity of the solid sorbent can fall by as much as 90 mol% after the first 20 carbonation–regeneration cycles. In this study a variety of techniques were employed to understand better the cause of this deterioration from both a structural and morphological standpoint. X-ray and neutron PDF studies were employed to understand better the local surface and interfacial structures formed upon reaction, finding that after carbonation the surface roughness is decreased for CaO.In situsynchrotron X-ray diffraction studies showed that carbonation with added steam leads to a faster and more complete conversion of CaO than under conditions without steam, as evidenced by the phases seen at different depths within the sample. Finally,in situX-ray tomography experiments were employed to track the morphological changes in the sorbents during carbonation, observing directly the reduction in porosity and increase in tortuosity of the pore network over multiple calcination reactions.
Proteomic analysis of ginsenoside Re attenuates hydrogen peroxide-induced oxidative stress in human umbilical vein endothelial cells
Authors: Huang Gui-dong , Zhong Xian-feng , Deng Ze-yuan , Zeng Rong
Published: April 2016

Ginsenoside Re is an active component in ginseng that has attracted much attention because of its evident therapeutic effects on the cardiovascular system.
Rosemary extracts in functional foods: extraction, chemical characterization and incorporation of free and microencapsulated forms in cottage cheese
Authors: Ribeiro Andreia , Caleja Cristina , Barros Lillian , Santos-Buelga Celestino , Barreiro Maria Filomena , Ferreira Isabel C. F. R.
Published: April 2016

The bioactivity of the cottage cheese was better preserved with microencapsulated rosemary extracts.
Chemical characterization and bioactive properties of two aromatic plants: Calendula officinalis L. (flowers) and Mentha cervina L. (leaves)
Authors: Miguel María , Barros Lillian , Pereira Carla , Calhelha Ricardo C. , Garcia Pablo A. , Castro Ma Ángeles , Santos-Buelga Celestino , Ferreira Isabel C. F. R.
Published: April 2016

M. cervina showed the highest concentration of phenolic compounds and the best antioxidant and cytotoxic activities, while C. officinalis presented higher amounts of sugars, organic acids and tocopherols.
Dietary polysaccharides and polyphenols can promote health by influencing gut microbiota populations
Authors: Conlon Michael A. , Topping David L.
Published: April 2016

Guest editors Michael Conlon and David Topping introduce this themed collection on foods, the large bowel microbiota and health outcomes.
One small molecule as a theranostic agent: naphthalimide dye for subcellular fluorescence localization and photodynamic therapy in vivo
Authors: Zhang Lei , Lei Kecheng , Zhang Jingwen , Song Wenlin , Zheng Yuanhong , Tan Shaoying , Gao Yuwei , Xu Yufang , Liu Jianwen , Qian Xuhong
Published: April 2016

A small single-molecule theranostic agent based on naphthalimide was developed, which possessed both bright fluorescence imaging and effective photodynamic therapeutic treatment.
Charge-tunnelling and self-trapping: common origins for blinking, grey-state emission and photoluminescence enhancement in semiconductor quantum dots
Authors: Osborne M. A. , Fisher A. A. E.
Published: April 2016

Modelling quantum dot blinking, grey-states and photoluminescence enhancement within a charge-tunnelling and self-trapping description of exciton-carrier dynamics.
The mechanical bond on carbon nanotubes: diameter-selective functionalization and effects on physical properties
Authors: Martínez-Periñán Emiliano , de Juan Alberto , Pouillon Yann , Schierl Christoph , Strauss Volker , Martín Nazario , Rubio Ángel , Guldi Dirk M. , Lorenzo Encarnación , Pérez Emilio M.
Published: April 2016

The formation of MINTs is diameter-selective and produces distinct effects on properties of the SWNTs, clearly different from supramolecular references.
Rhodium-catalyzed C–C coupling reactions via double C–H activation
Authors: Li Shuai-Shuai , Qin Liu , Dong Lin
Published: April 2016

Various rhodium-catalyzed double C–H activations are reviewed, in which rhodium(iii) catalysis shows good selectivity and reactivity to construct C–C bonds.
Total chemical synthesis of lassomycin and lassomycin-amide
Authors: Lear S. , Munshi T. , Hudson A. S. , Hatton C. , Clardy J. , Mosely J. A. , Bull T. J. , Sit C. S. , Cobb S. L.
Published: April 2016

Herein we report a practical synthetic route to the lasso peptide lassomycin (1) and C-terminal variant lassomycin-amide (2).
Mechanically linked poly[2]rotaxanes constructed from the benzo-21-crown-7/secondary ammonium salt recognition motif
Authors: Wang Peng , Gao Zhao , Yuan Ming , Zhu Junlong , Wang Feng
Published: April 2016

Mechanically linked poly[2]rotaxanes have been designed and synthesized, which displays interesting thermal and rheological properties due to the integration of [2]rotaxane moieties into the polycaprolactone chains.
A novel calix[4]arene-based bifunctional squaramide organocatalyst for enantioselective Michael addition of acetylacetone to nitroolefins
Authors: Vural Ummu , Durmaz Mustafa , Sirit Abdulkadir
Published: April 2016

A new chiral calix[4]arene-based organocatalyst3bearing bis-squaramide moieties was designed and synthesized fromp-tert-butylcalix[4]arene. This bifunctional organocatalyst was used in the enantioselective conjugate addition of acetyl acetone to β-nitrostyrenes. The corresponding adducts were obtained in good to excellent yields with high enantioselectivities.
Synthesis of activated carbon/polyaniline nanocomposites for enhanced CO2 adsorption
Authors: Khalili S. , Khoshandam B. , Jahanshahi M.
Published: April 2016

A new insight to investigate the potential applicability of different nanostructures of a PANI composite with activated carbon for CO2 adsorption.
Significantly improving mechanical, thermal and dielectric properties of cyanate ester resin through building a new crosslinked network with unique polysiloxane@polyimide core–shell microsphere
Authors: Dong Xinyi , Zhang Zhijuan , Yuan Li , Liang Guozheng , Gu Aijuan
Published: April 2016

Tough, rigid and thermally resistant resins with outstanding dielectric properties were developed based on polysiloxane@polyimide core–shell microspheres and cyanate ester.
Bacterial siderophore mimicking iron complexes as DNA targeting antimicrobials
Authors: Boda Sunil Kumar , Pandit Subhendu , Garai Aditya , Pal Debnath , Basu Bikramjit
Published: April 2016

Microbial secretion of siderophores for iron uptake can be employed as an efficient strategy to smuggle in bactericidal agents by conjugation to iron.
Synthesis and visible light responsed photocatalytic activity of Sn doped Bi2S3 microspheres assembled by nanosheets
Authors: Jiang Yifan , Hu Juncheng , Li Jinlin
Published: April 2016

The Sn4+ could act as trapping site of photo-generated electrons to promote the photocatalytic activity.
Investigation of the effects of nanoAg on the enzyme lysozyme at the molecular level
Authors: Guo Dandan , Zhang Bin , Liu Rutao
Published: April 2016

The toxicity of nanoAg may be explained by its surrounding smaller lysozyme, and its release of silver ions.
Assessment of solar photocatalytic degradation and mineralization of amoxicillin trihydrate (AMT) using slurry and fixed-bed batch reactor: efficacy of parabolic trough collector
Authors: Dixit Divya , Verma Anoop , Gupta Saurabh , Bansal Palak
Published: April 2016

Heterogeneous photocatalytic mineralization of amoxicillin trihydrate (AMT) using TiO2in suspended and supported form has been investigated in the present study.
Influences of nitrogen partial pressure on the optical properties of copper nitride films
Authors: Xiao Jianrong , Qi Meng , Cheng Yong , Jiang Aihua , Zeng Yaping , Ma Jiafeng
Published: April 2016

Cu3N films were prepared by radio frequency magnetron sputtering techniques and the optical properties of the films were investigated.
Electroselective α-bromination of acetophenone using in situ bromonium ions from ammonium bromide
Authors: Jagatheesan R. , Joseph Santhana Raj K. , Lawrence S. , Christopher C.
Published: April 2016

A greener and expeditious method for the side chain bromination of acetophenone using in situ generated bromonium ions from NH4Br in a H2O:CH3CN medium at ambient temperature has been developed in an undivided cell equipped with a Pt/Pt electrode.
Modulating the mixed micellization of CTAB and an ionic liquid 1-hexadecyl-3-methylimidazollium bromide via varying physical states of ionic liquid
Authors: Chadha Chanda , Singh Gurbir , Singh Gurpreet , Kumar Harsh , Kang Tejwant Singh
Published: April 2016

The physical nature of [C16mim][Br] as monomers/micelles led to different IL–CTAB mixed self-assembled structures.
Amide exchange reaction: a simple and efficient CuO catalyst for diacetamide synthesis
Authors: Li Qinghe , Wang Peixue , Deng Youquan
Published: April 2016

Synthesis of hexamethylenebisacetamide (HMBA) from hexamethylenediamine (HDA), CH3CN and H2O catalyzed by CuO without an organic solvent and gas protection.
Folic acid targeted pH-responsive amphiphilic polymer nanoparticles conjugated with near infrared fluorescence probe for imaging-guided drug delivery
Authors: Fu Liyi , Liu Le , Ruan Zheng , Zhang Houbing , Yan Lifeng
Published: April 2016

A novel folic acid targeted pH-responsive amphiphilic polymer conjugated with near infrared (NIR) probe has been synthesized by the combination of RAFT polymerization, ring-opening polymerization of N-carboxy anhydride (NCA) and click reaction.
Kinetic and thermodynamic study of the interactions between human carbonic anhydrase variants and polystyrene nanoparticles of different size
Authors: Assarsson A. , Nasir I. , Lundqvist M. , Cabaleiro-Lago C.
Published: April 2016

The protein packing at the surface may increase as the size of particles decreases given the right particle–protein characteristics.
DFT study of ethanol dehydration catalysed by hematite
Authors: Lopes Juliana F. , Silva Juliana C. M. , Cruz Maurício T. M. , Carneiro José Walkimar de M. , De Almeida Wagner B.
Published: April 2016

Ethanol dehydration process: energy barrier and rate constant, k(T), at room temperature. Gas phase and hematite model catalytic (FenO3/2n) results.
Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents
Authors: Hirose Daisuke , Gazvoda Martin , Košmrlj Janez , Taniguchi Tsuyoshi
Published: April 2016

Catalytic Mitsunobu reactions have been substantially improved based on strict optimization, mechanistic studies and discovery of a new catalyst.
Polydopamine coated shape memory polymer: enabling light triggered shape recovery, light controlled shape reprogramming and surface functionalization
Authors: Li Zhen , Zhang Xiaoyong , Wang Shiqi , Yang Yang , Qin Benye , Wang Ke , Xie Tao , Wei Yen , Ji Yan
Published: April 2016

Simple dip-coating transforms thermally responsive shape memory polymers into photo-responsive materials and allows for shape engineering and surface functionalization.
Divergent enantioselective synthesis of hapalindole-type alkaloids using catalytic asymmetric hydrogenation of a ketone to construct the chiral core structure
Authors: Liu Yang , Cheng Li-Jie , Yue Hai-Tao , Che Wen , Xie Jian-Hua , Zhou Qi-Lin
Published: April 2016

A divergent enantioselective approach to hapalindole-type alkaloids featuring a ruthenium-catalyzed asymmetric hydrogenation and a switchable sequence of methylation and acetylation/aldol reaction is described.
Anisotropic effective interactions and stack formation in mixtures of semiflexible ring polymers
Authors: Poier Peter , Bačová Petra , Moreno Angel J. , Likos Christos N. , Blaak Ronald
Published: April 2016

Binary mixtures of semiflexible ring polymers form stacks at high densities.
Influence of particle size, cycling rate and temperature on the lithiation process of anatase TiO2
Authors: Liu H. , Grey C. P.
Published: April 2016

A continuous structural change during the (de)lithiation of lithium-ion battery material, anatase TiO2, which undergoes a crystal symmetry change, was not found even at high rates.
Fingerprint orientation field regularisation via multi‐target regression
Authors: Lin Lu , Liu Eryun , Wang Lianghao , Zhang Ming
Published: April 2016

Orientation field estimation is a key step in fingerprint feature extraction and recognition. A complete orientation field estimation algorithm usually consists of two steps, i.e. initial orientation field estimation and post regularisation. In this Letter, a multi‐target regression model to regularise the initial orientation field is proposed. A large number of orientation patches with simulated noises, together with their regression targets are fed to a deep neural networks to train a multi‐target regression model. For a given initial orientation field at testing stage, a refined orientation field is obtained by applying the regression model in patch‐wise and then combining all predicted patches. Experimental results on FVC2002, FVC2004 and FVC2006 databases show remarkable performance compared with state of the art algorithms. Our algorithm is also highly efficient and easy to implement.
Extended Wang neural network for online solving a set of linear equations
Authors: Li Zhan , Yin Ziguang
Published: April 2016

An extended Wang neural network (EWNN) is proposed to solve online a set of linear equations. Such EWNN is possessing the general nonlinear model form with redundant parts, to face existence of nonlinearity phenomena in circuit implementation of Wang neural network (WNN). Furthermore, two types of nonlinear activation are proposed for EWNN aiming to improve the convergence of the WNN. Illustrative results verify the proposed EWNN for online solving linear equations.
Short wavelength enhanced phototransistor with n‐doped porous silicon layer
Authors: Wang Yao‐Chin , Lin Bor‐Shyh , Yang Zu‐Po
Published: April 2016

A phototransistor with aluminium (Al)/porous silicon (Si)/epitaxial‐Si structures was proposed and was fabricated and characterised with short wavelength enhanced operating. We proposed the short wavelength response of the Si‐based thin film phototransistor; it can be enhanced by introducing thin porous Si (PS) layer as the base region of transistor. The porous process of device manufacture is suitable for applications in design of visible‐light sensitive phototransistors. Experimental results showed that the short wavelength responses in the developed devices were enhanced as compared with the Si‐based homojunction transistors, this comparably medium optical gain indicated that the developed Al/PSi/epitaxial‐Si heterojunction thin film phototransistor got potential for practical Si‐based optical‐electron integrated‐circuit and biophotonics applications.
Two‐stage beamforming training for multi‐user millimetre wave systems
Authors: Zhao Peiyao , Wang Zhaocheng , Dai Linglong
Published: April 2016

Hybrid analogue/digital precoding technique is widely considered for multi‐user millimetre wave (mmWave) systems to reduce the cost and power consumption of radio frequency chains, where beamforming (BF) training is required for the configuration of analogue BF/combining vectors of multiple user equipments (UEs). However, the conventional BF training algorithms suffer from high training overhead increasing with the number of UEs. To address this problem, a two‐stage BF training mechanism is proposed for multi‐user mmWave systems with time division duplex mode by dividing the BF training process into downlink broadcasting and uplink training. Consequently, multiple UEs can be trained simultaneously and the feedback operation is eliminated. Simulation results demonstrate that the proposed two‐stage BF training scheme approaches the optimal performance of exhaustive search with much reduced training overhead.
Short‐wave infrared photodetector with high responsivity and signal‐to‐noise ratio
Authors: Zhang Yue
Published: April 2016

Short‐wave infrared photodetectors with a p‐charge layer and double barrier structure are designed and fabricated by molecular beam epitaxy. The current intensity is lowered by three orders of magnitude compared with the detector without the p‐charge layer. The tested responsivity of the detector is 485 A/W at 0.31 V, when the power of the incident light is 10 nW. By adding the p‐charge layer, the signal‐to‐noise ratio of the detector is promoted by 30 times, which reaches 1712 at 0.3 V, when the power of the incident light is 1 nW.
Voltage clamping circuit with ±100 mV precision in high‐voltage OTA
Authors: Easwaran S.N. , Venugopal S.K. , Weigel R.
Published: April 2016

It is shown that precise output voltage clamping levels can be achieved under any operating condition by clamping the input of operational transconductance amplifier to a process insensitive reference and multiplexing the levels based on comparator decision. This circuit was implemented in a 40 V bipolar CMOS process. The fabricated circuit clamps the output voltage at 5.4 V with a precision of ±100 mV at 175°C on‐chip junction temperature on the die. The input range for this circuit is between 100 mV and 25 V.
Second‐order charge‐sampling structure utilising passive scheme to implement complex conjugate poles
Authors: Sohrabi Z. , Jannesari A.
Published: April 2016

A second‐order charge‐sampling structure is proposed which enables the implementation of complex conjugate poles. The proposed structure avoids the use of any extra active element and reaches the desired response by modifying the switching scheme and inserting a feedback mechanism in the operation of the filter. Simulation results show that the proposed structure is capable of implementing a Butterworth filter.
Non‐foster impedance matching sensitivity of electrically small electric and magnetic spherical dipole antennas
Authors: Yoon I.‐J. , Christensen S. , Zhurbenko V. , Kim O.S. , Breinbjerg O.
Published: April 2016

The impedance bandwidth (BW) improvement property of a self‐resonant folded spherical helix electric dipole and a spherical split ring (SSR) magnetic dipole is compared when a negative reactance element is loaded on the parasitic resonator of the antennas. They have the same electrical size of ka = 0.38 and both approach each lower Q‐bound. It is found that the impedance characteristic reacts more sensitively to the loaded element for the SSR antenna due to the inherent two‐times higher Q of the magnetic antenna. It is also found that a conventional non‐Foster circuit composed of a series negative inductor and a capacitor cannot be used for wide impedance matching of the SSR antenna due to the high sensitivity. Subsequently, a circuit topology that enables more precise matching of the reactive values for widened impedance matching in the high‐Q SSR antenna and satisfies the stable operating condition is proposed. It is observed that the improvement ratio of the BW is limited in practical situation. Nevertheless, the measured reflection coefficient of the 3D‐printed SSR antenna loaded with the designed active matching circuit shows two‐times wider impedance BW than passive matching, verifying the simulated result from the circuit and electromagnetic (EM) simulations.
High‐performance operation of distributed feedback terahertz quantum cascade lasers
Authors: Li Yuanyuan , Liu Junqi , Liu Fengqi , Zhang Jinchuan , Wang Zhanguo
Published: April 2016

Carefully designed distributed feedback terahertz quantum cascade lasers based on surface metallic‐stripe grating structure are presented. Stable single‐mode emission with a side‐mode suppression ratio of >20 dB is obtained under all injection currents and operating temperatures. Maximum edge‐emitting power of 58 mW is realised in continuous‐wave mode. In pulsed mode, record output powers of 286 mW at 10 K and 82 mW at 77 K are achieved at 97.1 μm with a well‐shaped beam pattern.
Improvement of current drivability in high‐scalable tunnel field‐effect transistors with CMOS compatible self‐aligned process
Authors: Kim S.W. , Sun M.‐C. , Park E. , Kim J.H. , Kwon D.W. , Park B.‐G.
Published: April 2016

Two strategies are introduced herein to improve current drivability of tunnel field‐effect transistors (TFETs). First, gate‐to‐channel coupling is increased by ∼22% in terms of effective gate capacitance (Cox) with the help of hemi‐cylindrical device architecture. A novel iterative corner rounding process was developed for highly reliable gate dielectric formation without field crowding at sharp corner. The second approach is change channel orientation. The 〈100〉 and 〈110〉 oriented‐channel TFETs were fabricated on (100) silicon surface. Consequently, both planar and hemi‐cylindrical structures show consistent results that 〈110〉 is far better than 〈100〉 for higher on‐current (Ion). With these two structural improvements, the 〈110〉 hemi‐cylindrical TFET shows ∼30× higher Ion than that of the control (i.e. 〈100〉 planar TFET).
Using the 0‐1 test for chaos to detect hardware trojans in chaotic bit generators
Authors: Melosik M. , Marszalek W.
Published: April 2016

The use of the 0‐1 test for chaos to monitor chaotic bit generators susceptible to unauthorised changes and modifications of the circuits’ parameters (hardware trojans) is presented. The 0‐1 test proves that the chaotic nature of the continuous time signals is inherited by the bit sequences even when a simple threshold comparator is used. Simulation results with the Chua and Lindberg–Murali–Tamasevicius circuits are presented.
3‐D non‐uniform time step locally one‐dimensional FDTD method
Authors: Yang Zaifeng , Tan Eng Leong
Published: April 2016

A 3‐D non‐uniform time step locally one‐dimensional finite‐difference time‐domain (NUTS LOD‐FDTD) method is presented. Unlike conventional and the other LOD‐FDTD methods, NUTS LOD‐FDTD method employs NUTS for different periods during the simulation. The update equation of NUTS LOD‐FDTD method with arbitrary time step is given. Numerical results are provided to compare with conventional LOD‐FDTD method and trade‐off between efficiency and accuracy for different NUTSs.
Information theoretical performance analysis and optimisation of cooperative underwater acoustic communication systems
Authors: Nouri Hatef , Uysal Murat , Panayirci Erdal
Published: April 2016

In this study, the authors investigate the information theoretical limits on the performance of single‐carrier cooperative underwater acoustic communication systems in the presence of intersymbol interference. The authors assume decode‐and‐forward relaying and consider orthogonal half‐duplex cooperation. Under the assumptions of sparse and frequency‐selective Rician fading channel and non‐white correlated Gaussian ambient noise, the authors derive expressions for bounds on the individual and achievable rates for both cases where channel state information is available at the transmitter or not. Using these expressions, the authors optimise input signalling and relay location to maximise average achievable rates.
Energy‐efficiency resource allocation for cognitive heterogeneous networks with imperfect channel state information
Authors: Chen Jian , Zhou Yuchen , Kuo Yonghong
Published: April 2016

In this study, the authors focus on the downlink resource allocation to optimise energy‐efficiency (EE) of orthogonal frequency division multiplexing‐based cognitive heterogeneous network (HetNet), where network service providers operate multi‐radio access technologies. A more practical case is considered, in which imperfect channel state information (CSI) is available for wireless channels between secondary base stations and secondary users (SUs), primary users (PUs). Since imperfect CSI may result in outage in secondary networks and make collision occur in primary networks, a joint subcarrier and power allocation scheme for the cognitive HetNet is proposed to guarantee quality of service requirements for both SUs and PUs in probabilistic manners. Then the probabilistic EE optimisation scheme is approximated into a deterministic convex form, and the optimal solutions for the scheme are derived by double‐loop iteration method. Afterwards, the authors develop a low‐complexity algorithm in the presence of imperfect CSI with a small reduction of system performance. Simulation results are provided to show the impact of channel estimation error on the EE optimisation problem and to highlight the performance improvement from considering channel estimation error in the joint subcarrier and power allocation scheme for the cognitive HetNet system.
Component and parameterised power model for cloud radio access network
Authors: Alhumaima Raad S. , Khan Muhammad , Al‐Raweshidy Hamid S.
Published: April 2016

The fifth generation cellular network performance is measured by its spectral and energy efficiency (EE). Densifying the network might provide a solution. However, this will lead to tremendous network infrastructure and increased power consumption (PC). Cloud radio access network (C‐RAN) has emerged as a solution to curtail the PC and deliver spectrum sharing in a cost‐effective and energy‐efficient way. Since the PC is an important key success for the upcoming generations, and in order to study and evaluate the power reductions achievable by C‐RAN, a reliable power model (PM) is required. This study proposes a component, linear and parameterised PMs to explore the individual components relevant for PC analysis, particularly for C‐RAN architecture. The models quantify the EE by capturing the power consumed by individual components, and the amount of power reduced in the network. The model shows a dramatic reduction in the cooling PC (87.4%), whereas the total PC is reduced to about (33.3%) compared with macro base stations deployment. Finally, accuracy comparison of the component and parameterised models has been presented.
State‐based potential power allocation game in a cooperative multiuser network
Authors: Vassaki Stavroula , Poulakis Marios I. , Panagopoulos Athanasios D.
Published: April 2016

Multiuser cooperative communications represent a research area of great interest constituting a key technology for future wireless networks. In this study, the authors consider a scenario of multi‐user, single‐relay network, where each user employs a part of the relay's transmission power taking into account the constraint of the total transmission power of the relay. The problem of relay power allocation to individual users with a view to optimising the long‐term network performance is investigated. An adequate utility function is defined, in terms of outage probability, evaluating the cooperative network's performance due to the relay's cooperation. Taking into consideration the distributed nature of cooperative networks along with the coupled constraint of relay's total transmission power, the specific problem is transformed from a network‐level to a user‐level optimisation problem using a modern game‐theoretic tool. More specifically, the initial power allocation problem is formulated as a state‐based potential game for which the corresponding Nash equilibrium exists. Finally, a gradient learning mechanism is proposed to achieve the stationary state Nash equilibrium of the game that constitutes also the global optimal solution of the initial problem. The performance of the new proposed scheme is investigated through numerical simulations for various network parameters.
Side information embedding and detection scheme for selected mapping based single‐carrier frequency‐division multiple access systems
Authors: Wu Kun , Ren Guangliang , Ji Jinwei , Wu Jueying
Published: April 2016

Selected mapping (SLM) works effectively in peak‐to‐average power ratio reduction for the single‐carrier frequency‐division multiple access (SC‐FDMA) system. However, the need for side information (SI) transmission results in data rate loss and increase of the system complexity. To avoid explicit SI transmission for SLM‐based SC‐FDMA systems, an SI embedding and detection scheme is proposed by exploiting the block pilot symbols. Specifically, to enable SI embedding, the authors propose to represent the SI index for each data symbol in the subframe by a location set of some selected subcarriers in the block pilot symbol. For SI detection, an optimal pilot‐aided maximum‐likelihood SI detector is presented. As a low‐complexity alternative, a suboptimal log‐likelihood ratio SI detector is also proposed. In addition, the authors provide theoretical analysis of SI detection error rate and discuss the effect of the proposed scheme on channel estimation. Simulation results show that, in SLM‐based SC‐FDMA systems, the proposed scheme significantly outperforms existing methods in terms of both SI detection and bit error rate (BER) and achieves the same BER performance as its counterpart with perfect SI.
A sufficient bit rate condition for mean‐square stabilisation of linear systems over multiple lossy networks
Authors: Ling Qiang
Published: April 2016

This article studies the mean‐square stability of quantised linear systems which transmit both measurement and control data over multiple lossy communication networks with independent and identically distributed dropouts. By modifying previous quantisation policies, it proposes a multi‐stage lifted quantisation policy for systems with multiple networks. That policy allows that these networks can parallely transmit data packets, i.e. all networks simultaneously work to transmit data packets. Due to such parallel transmission, we can obtain a less conservative sufficient stabilising bit rate condition, which is determined only by the unstable eigenvalues of the concerned system and the worst (highest) dropout rate of networks and is irrelevant to the number of concerned networks.
Universal adaptive control of feedforward time‐delay systems with lower‐ and higher‐order non‐linearities
Authors: Jia X. , Lu J. , Xu S.
Published: April 2016

This study considers a class of high‐order feedforward non‐linear time‐delay systems with lower‐ and higher‐order non‐linearities. Owing to the upper‐triangular structure, backstepping‐like methods are in general not applicable. To overcome this difficulty, the authors introduce a dynamic gain scaling transformation and construct a novel dynamic gain that is used to compensate the unknown parameter in the sense of universal adaptive control. With the help of the adding a power integrator technique and the Lyapunov–Krasovskii theorem, a delay‐independent controller with a novel dynamic gain is explicitly constructed under the condition of less conservative assumption, to globally asymptotically regulate all states of origin system to zero as time goes to infinity while guaranteeing that the dynamic gain is uniformly bounded. Finally, an illustrative example is given to show the usefulness of the proposed design method.
Consensus for multi‐agent systems with distributed adaptive control and an event‐triggered communication strategy
Authors: Xie Duosi , Xu Shengyuan , Zhang Baoyong , Li Yongmin , Chu Yuming
Published: April 2016

This study addresses the consensus problem of multi‐agent systems by combining adaptive control protocol and event‐triggered communication strategy. Two adaptive protocols are designed to guarantee the consensus. The event‐triggered communication strategy is utilised to save communication and reduce channel occupation. Each agent in the system sends its state to neighbours only at some irregular event instants determined by an appropriately designed event‐triggering condition. At first, the distributed event‐triggering condition of an agent only employs the state of its own and the state of the neighbours at their latest event instants. Later, another event‐triggering condition is given such that no global parameter is required for agents, such as the maximum eigenvalue of the Laplacian matrix. It is proven that the system can reach consensus by utilising the proposed control method. Illustrative examples are given to show the effectiveness of the control strategy.
Analysis of unbalanced magnetic pull in eccentric interior permanent magnet machines with series and parallel windings
Authors: Jiang James Weisheng , Bilgin Berker , Sathyan Anand , Dadkhah Hossein , Emadi Ali
Published: April 2016

The effects of different winding connections, i.e. series, parallel, and series–parallel combined windings is studied, on the unbalanced magnetic pull (UMP) in an interior permanent magnet synchronous machine (IPMSM) with eccentricity applied. Three types of eccentricities, i.e. static, dynamic, and mixed eccentricities, are investigated. Four types of winding connections are examined and the contributing factors, such as air gap difference, current redistribution, and slot effect on the UMP are analysed. FFT analysis and UMP distribution patterns are used to compare the four types of winding connections. The results show that the current redistribution generated by the parallel connections of the windings results in reduction of UMP for IPMSM with eccentricity.
Analysis of permanent magnet brushless AC motor using Fourier transform approach
Authors: Dwivedi Ankita , Singh Santhosh Kumar , Srivastava Rakesh Kumar
Published: April 2016

The paper presents an analytical model for determining performance characteristics of surface mounted permanent magnet brushless motor using Fourier transform technique. The proposed scheme assumes a simplified geometric model of surface mounted PM (SMPM) motor with dual current sheets using layer theory to analyse electrical machines. The layer theory considers regions of PMBLAC motor to be replaced by layers of respective homogeneous material properties. Isotropic model assumes stator to be sloltless while anisotropic model is also considered to account for stator slotting effect on the motor performance. The Fourier transform applicable to linear induction motor and introduced by S. Yamamura is modified and adapted for analysing PMBLAC motor. The primary stator winding and permanent magnets on rotor are replaced by their respective equivalent linear current densities. The proposed model is validated using experimental results from a 12‐slot surface mounted PMBLAC motor. The proposed method is capable of calculating the effect of design parameters on the performance of the SMPM motor, thus making it suitable for design and optimisation at initial stage. Moreover, analytical validation is also presented to prove the effectiveness of the proposed method.
Switched reluctance motor for hybrid motion control: design, modelling, and sensorless drive
Authors: Nezamabadi Mohammad Mehdi , Afjei Ebrahim
Published: April 2016

A new switched reluctance motor for hybrid motion control is presented in this study. The motor can control both motions simultaneously and separately. A dedicated sensorless drive is developed for each kind of motion based on diagnostic pulse injection method. Eliminating the position sensors in the motor with two degrees of freedom reduces the manufacturing cost and complexity. Each kind of motion is controlled independently therefore no decoupling algorithm is required. The motor has been mainly designed to eliminate rotary to linear gears to be used as an automatic drilling tool. The cylindrical translators let simultaneous excitation of all coils on the linear stator and provide short magnetic flux paths which reduce the magnetic core losses and increase the force per volume. The motor design is verified initially by running three‐dimensional finite‐element analysis (FEA) on both rotary and linear sections. The motor is fabricated and tested in the lab utilising the sensorless drive. Accordance of experimental values with the FEA results certifies the performance and applicability of the motor.
Design of an X‐band Vivaldi antenna with low radar cross section
Authors: Natarajan Rajesh , Kanagasabai Malathi , George Jithila V.
Published: April 2016

In this study, a passive Vivaldi antenna design is proposed for radar cross section (RCS) reduction using object shaping method. The implementation of annular slot along with exponential curves in the radiator reduced the scattering along the surface of the radiator. This contributes reduction in structural mode RCS throughout the operational bandwidth without affecting the impedance performance of the antenna. Monostatic RCS of the antenna is discussed for two incident angles. A minimum RCS reduction of 13 dB is achieved when the incident angle is Θ = 60° and a maximum of 19 dB reduction is achieved at Θ = 75°. The proposed antenna offers symmetric radiation pattern in both azimuth and elevation planes and also maintains co‐polarisation to cross‐polarisation ratio of 19 dB throughout the X‐band (8–12 GHz). Prototype antenna is fabricated and tested to validate the simulated results.
Carrier‐less fault‐tolerant stochastic synthesis in multi‐cell multi‐level converters: a central limit approach to highly‐dimensional power electronic systems
Authors: Tenca Pierluigi , Peretti Luca
Published: April 2016

As the number of cells in multi‐level converters increase, issues related to the high number of subsystems enter the power electronics area. Within this frame, this study presents a carrier‐less approach to the voltage synthesis across the series of several voltage‐source cells in multi‐level converter topologies. The key idea is the exploitation of a stochastic‐based choice of the discrete cell output voltage, operating according to a local, independent random variable. When the number of cells is sufficiently high, the law of large numbers and the central limit theorem (CLT) of the probability theory guarantee that the synthesis of the total voltage lies in a known interval with high probability. Because of the CLT stochastic properties, an increased number of cells inherently leads to more robust and fault‐tolerant waveforms, also due to the reduced capacitors required in each cell. The absence of deterministic modulation reduces the hardware cost (cabling and control) and requires no reconfiguration in case of cell failures. This work focuses on the theoretical and hardware‐in‐the‐loop validation of the main principle, including an analysis of the capacitance requirements for each cell. The method could be also applied to current‐source multi‐level converters based on parallel connections of current‐source cells.
Comparison of three‐phase three‐level voltage source inverter with intermediate dc–dc boost converter and quasi‐Z‐source inverter
Authors: Panfilov Dmitry , Husev Oleksandr , Blaabjerg Frede , Zakis Janis , Khandakji Kamal
Published: April 2016

This study compares a three‐phase three‐level voltage source inverter with an intermediate dc–dc boost converter and a quasi‐Z‐source inverter in terms of passive elements values and dimensions, semiconductor stresses, and overall efficiency. A comparative analysis was conducted with relative parameters to evaluate converter parameters for any application. The equations obtained were confirmed by simulation and experimental setup. Field of application has been discussed.