bluuebunny/crossref_metadata_2025 huggingface dataset:
Dye colour switching by hydride-terminated silicon particles and its application as an oxygen indicator
Authors: Ye Miaomiao , Qian Chenxi , Sun Wei , He Le , Jia Jia , Dong Yuchan , Zhou Wenjie
Published: April 2016

Redox dyes can be rapidly decolorized by hydride-terminated silicon particles and their original colors recovered when exposed to an oxygen environment. With this knowledge, a polymer–dye-based film was assembled and shown to function as an oxygen indicator.
Macrocyclic oligoarylamines as hole- and spin-containing scaffolds for molecule-based electronics
Authors: Ito Akihiro
Published: April 2016

Macrocyclic oligoarylamines with a variety of arene-bridged patterns and their various features as hole- and spin-containing scaffolds are reviewed.
Dysregulation of ossification-related miRNAs in circulating osteogenic progenitor cells obtained from patients with aortic stenosis
Authors: Takahashi Kan , Satoh Mamoru , Takahashi Yuji , Osaki Takuya , Nasu Takahito , Tamada Makiko , Okabayashi Hitoshi , Nakamura Motoyuki , Morino Yoshihiro
Published: April 2016

CAVD (calcific aortic valve disease) is the defining feature of AS (aortic stenosis). The present study aimed to determine whether expression of ossification-related miRNAs is related to differentiation intro COPCs (circulating osteogenic progenitor cells) in patients with CAVD. The present study included 46 patients with AS and 46 controls. Twenty-nine patients underwent surgical AVR (aortic valve replacement) and 17 underwent TAVI (transcatheter aortic valve implantation). The number of COPCs was higher in the AS group than in the controls (P<0.01). Levels of miR-30c were higher in the AS group than in the controls (P<0.01), whereas levels of miR-106a, miR-148a, miR-204, miR-211, miR-31 and miR-424 were lower in the AS group than in the controls (P<0.01). The number of COPCs and levels of osteocalcin protein in COPCs were positively correlated with levels of miR-30a and negatively correlated with levels of the remaining miRNAs (all P<0.05). The degree of aortic valve calcification was weakly positively correlated with the number of COPCs and miR-30c levels. The number of COPCs and miR-30c levels were decreased after surgery, whereas levels of the remaining miRNAs were increased (all P<0.05). Changes in these levels were greater after AVR than after TAVI (all P<0.05). In vitro study using cultured peripheral blood mononuclear cells transfected with each ossification-related miRNA showed that these miRNAs controlled levels of osteocalcin protein. In conclusion, dysregulation of ossification-related miRNAs may be related to the differentiation into COPCs and may play a significant role in the pathogenesis of CAVD.
NDA SNR estimation using fourth‐order cross‐moments in time‐varying single‐input multiple‐output channels
Authors: Ben Salah Mohamed Bassem , Samet Abdelaziz
Published: April 2016

In this study, the authors propose a moment‐based estimator of the signal‐to‐noise ratio (SNR) over time‐variant Rayleigh fading single‐input multiple‐output channels. The correlated time‐variant channel is modelled with the well‐known Jakes’ model. The authors’ approach uses the fourth‐order cross‐moments of the received signal to estimate the SNR with the presence of an additive white Gaussian noise which is uncorrelated between antenna elements. The SNR is deduced by estimating, respectively, the powers of the useful signals and the noise. The proposed SNR estimator is a non‐data‐aided (NDA) method since it does not require a training sequence. The performances of this algorithm are investigated in terms of normalised mean square error over a wide range of scenarios. Simulation results show that the proposed algorithm outperforms the NDA maximum‐likelihood‐based estimators and the moment‐based estimators.
Improved hybrid method for image super‐resolution
Authors: Xing Weiwei , Zhao Yahui , Bao Ergude
Published: April 2016

Improving image resolution has broad applications and is an important research topic. Recently, a hybrid method Adaptive Sparse Domain Selection (ASDS) combining a reconstruction‐based method and an example‐based method has been proposed to take advantage of the two, but may not reconstruct sufficient details. In this study, the authors propose to improve ASDS: Zeyde's method is first used to obtain an intermediate image with high‐frequency details, and then the obtained image is used to replace the autoregressive model of ASDS as the example‐based term. In addition, the authors may split the input image into patches and use different parameter settings for the patches of different amount of details. Experimental results demonstrate the improved hybrid methods can produce high‐quality images quantitatively and perceptually.
Research on sensorless and advanced angle control strategies for doubly salient electro‐magnetic motor
Authors: Zhou Xingwei , Zhou Bo , Guo Honghao , Wei Jiadan
Published: April 2016

This paper proposes a sensorless method for doubly salient electro‐magnetic motor (DSEM). The commutation signals are obtained through the comparison between the voltage of silent phase and a pre‐set threshold value based on the characteristic that the excitation back electromotive force (EBEMF) at commutation points is unaffected by the saturation of excitation field. Furthermore, in order to improve the torque output performance of DSEM, a novel sensorless advanced angle control (AAC) is investigated. Unlike traditional AAC, through piecewise linear fitting EBEMF in advance commutation interval, this method does not require the detection of standard commutation points. The experiments implemented on a 12/8‐pole DSEM validate the proposed methods over a wide range of speed and load conditions in both steady and dynamic procedures.
Application of intelligent tools to detect and classify broken rotor bars in three‐phase induction motors fed by an inverter
Authors: Godoy Wagner Fontes , da Silva Ivan Nunes , Goedtel Alessandro , Palácios Rodrigo Henrique Cunha , Lopes Tiago Drummond
Published: April 2016

A comprehensive study of intelligent tools used to classify broken rotor bars in induction motors, which operate with three different types of frequency inverters, is presented. The diagnosis of defective rotor bars is a critical issue for the predictive maintenance of induction motors. A proper classification of these defects in their early stages of evolution is necessary for preventing major machine failures and production downtime. The proposed approach is performed by analysing the amplitude of the stator current signal in the time domain, using a dynamic acquisition rate based on machine frequency supply. To assess classification accuracy under the various severity levels of the faults, the performance of four different learning machine techniques is investigated: (i) fuzzy ARTMAP network; (ii) support vector machine (sequential minimal optimisation); (iii) k‐nearest neighbour; and (iv) multilayer perceptron network. Results obtained from 1274 experimental tests are presented in order to validate the study, which considers a wide range of load conditions and operating frequencies. Experimental results presented in this study validate the robustness and efficacy of the proposed approach.
Analytical statistical study of beam‐pointing error in two‐dimensional coupled oscillator arrays
Authors: Hajian Hamid , Banai Ali
Published: April 2016

In this study, the authors investigate the effect of the random free‐running frequency distribution of oscillators in two‐dimensional (2D) coupled oscillator arrays (COAs) on the phase error of the elements, and consequently on the beam‐pointing angle of the array. They derive an analytic formulation for the standard deviation of the beam‐pointing error (BPE) in terms of the statistical parameters of the free‐running frequencies of the elements and array configuration. The results show that in order to decrease the BPE in 2D COAs, one can use COAs with a larger size (greater number of elements) and decrease the deviation of the free‐running frequency of the oscillators.
Improvement of microstrip patch antenna gain and bandwidth at 60 GHz and X bands for wireless applications
Authors: Rabbani Muhammad Saqib , Ghafouri‐Shiraz Hooshang
Published: April 2016

A method has been proposed to simultaneously enhance the gain (14 dB), bandwidth (BW) (12.84% of the operating central frequency) and efficiency (94%) of a microstrip patch antenna. The antennas have been designed based on the patch size improvement technique to improve the fabrication tolerance. The designed prototypes have been fabricated by conventional low cost printed circuit board etching method and tested at X‐band (8–12 GHz) and 60 GHz band (57–66 GHz) frequencies. Antennas’ overall performance is maintained across their operating frequency range. The tested antennas for 60 GHz band convince the requirements for multi‐gigabits/s data rate wireless local area network and wireless personal area network applications recommended by IEEE 802.11ad and IEEE 802.15.3c standards. In all cases the simulation and the measured results are in good agreement.
Button‐shaped radio‐frequency identification tag combining three‐dimensional and inkjet printing technologies
Authors: Liu Qi , Le Taoran , He Sailing , Tentzeris Manos M.
Published: April 2016

A ‘button‐shaped’ three‐dimensional (3D) radio‐frequency identification (RFID) tag combining 3D printing and inkjet printing technologies in fabrication for the first time is proposed. The button shape facilitates the tag's integration with clothes for the purposes of identification and access control. The proposed tag features a compact size (radius 15 mm, height 7.5 mm) and a good performance with a measured maximum reading range of 2.1 m (4.0 W equivalent isotropically radiated power) in the RFID Federal Communications Commission band (902–928 MHz). Furthermore, the combination of the 3D printing and inkjet printing technologies reduces the fabrication time and cost.
Commonality used to discriminate active repetition false targets based on polarisation characteristics of antenna
Authors: Zong Zhiwei , Shi Longfei , Wang Xuesong
Published: April 2016

Numerous active repetition false targets (RFTs) introduced by deception jammer with digital radio‐frequency memory system, which makes efficient use of jamming power, can easily exhaust the radar and interceptor resources of any defence system. On the basis of the idea of group treatment, a commonality in the polarimetric characteristics of multiple RFTs produced by one jammer is employed to discriminate them, after the simultaneous polarisation measurement is made by fully‐polarimetric defence radar. First, the commonality of RFTs will be extracted from the models of the jamming signals in two cases where the receiving and transmitting antennas of jammer are single‐ and dual‐polarised, respectively. The relationship equation between the two polarisation channels of defence radar will be derived in detail. Second, discrimination method will be introduced based on probability grids, and cumulative probabilities will be calculated to detect and discriminate RFTs. Simulation results obtained by using polarisation data measured from microwave anechoic chamber of physical target scale models indicate that the method is valid and feasible.
Improved focusing approach for highly squinted beam steering SAR
Authors: Guo Ping , Tang Shiyang , Zhang Linrang , Sun Guang‐Cai
Published: April 2016

For different applications with diverse requirements, many synthetic aperture radar (SAR) modes have been developed in the literature, such as, spotlight SAR, terrain observation by progressive scans (TOPS) SAR, and sliding spotlight SAR. For highly squinted beam steering SAR (BS‐SAR; spotlight SAR, sliding spotlight SAR, and TOPS SAR), the main challenge is to develop an efficient full‐aperture focusing approach since the mostly traditional algorithms fail to process the highly squinted BS‐SAR data without subaperture technique. In this study, a unified full‐aperture focusing algorithm is presented for BS‐SAR modes in the case of highly squint angle. The key of the algorithm lies in the linear multiplications applied in the range‐wavenumber and azimuth‐space domain, which can remove the azimuth spectral folding effect and the geometrical distortion caused by spectrum skewing. Moreover, there is no any approximation in the focusing procedure; thus, the presented algorithm can perform well. Since the subaperture is avoided, this improved focusing approach is highly efficient. Simulation results are presented to validate the proposed method.
Design of Maisel sidelobe blankers with a guarantee on the gap to optimality
Authors: Coşkun Osman , Candan Çağatay
Published: April 2016

The conventional sidelobe blanking system, known as the Maisel sidelobe blanker, uses two receiving channels with different gains to detect the presence of a jammer. The Maisel system is an ad‐hoc detector without any optimality properties. Yet, it has been successfully utilised in numerous operational systems. Here, the authors study the optimum Neyman–Pearson type sidelobe blanking (SLB) detectors for the Swerling target models to assist the design of Maisel blankers. The authors note that the optimal sidelobe blankers are of theoretical interest, since they require the knowledge of target and jammer parameters, which are typically not available at the radar site. The main goals of the present study are (i) to derive the optimal Neyman–Pearson detectors for SLB, (ii) to examine the performance gap between the optimal and Maisel detectors, and (iii) to develop objective criteria for the design of Maisel blankers that provides a guarantee on the gap to the optimality. Ready‐to‐use computer programs to assist the design process are also provided.
Monostatic radar range–Doppler sidelobe suppression using nearly orthogonal waveforms
Authors: Liu Hongwei , Zang Huikai , Zhou Shenghua , Cao Yunhe
Published: April 2016

Sidelobes of radar waveforms can cause many undesirable consequences. Inspirited by achievements in multiple‐input–multiple‐output radar, the authors study how to use and design a set of nearly orthogonal waveforms for monostatic radar with coherent accumulation operation to transmit at successive pulse repetition intervals (PRIs). As the range sidelobes at different PRIs cannot be coherently accumulated anymore during the coherent accumulation, the overall sidelobe level after coherent accumulation can be decreased significantly, which is verified by numerical results.
Frequency diverse array and MIMO hybrid radar transmitter design via Cramér–Rao lower bound minimisation
Authors: Gao Kuandong , Wang Wen‐Qin , Cai Jingye
Published: April 2016

Frequency diverse array (FDA) produces a range–angle‐dependent transmit beampattern and offers a potential solution to localise targets in two dimensions with respect to slant range and azimuth angle. However, it is difficult to unambiguously estimate the target location information by a standard FDA radar via conventional adaptive beamforming due to its coupling range–angle response. In this study, the authors propose two FDA and multiple‐input multiple‐output (MIMO) hybrid radar transmitter design schemes by minimising the Cramér–Rao lower bound (CRLB) for range‐dependent target localisation, namely, FDA–MIMO radar and transmit subarray FDA–MIMO (TS‐FDA) radar. The former uses a small frequency increment across the MIMO antennas, whereas the latter divides the FDA elements into multiple subarrays using the same waveform within each subarray and orthogonal waveforms in distinct subarrays. The formulated CRLB minimisation problem is solved by convex optimisation. Furthermore, the targets are localised using the beamspace‐based multiple signal classification algorithm. The designed FDA–MIMO and TS‐FDA radars are evaluated by comparing their mean square error and cumulative distribution function performance.
Protein sequestration versus Hill‐type repression in circadian clock models
Authors: Kim Jae Kyoung
Published: April 2016

Circadian (∼24 h) clocks are self‐sustained endogenous oscillators with which organisms keep track of daily and seasonal time. Circadian clocks frequently rely on interlocked transcriptional‐translational feedback loops to generate rhythms that are robust against intrinsic and extrinsic perturbations. To investigate the dynamics and mechanisms of the intracellular feedback loops in circadian clocks, a number of mathematical models have been developed. The majority of the models use Hill functions to describe transcriptional repression in a way that is similar to the Goodwin model. Recently, a new class of models with protein sequestration‐based repression has been introduced. Here, the author discusses how this new class of models differs dramatically from those based on Hill‐type repression in several fundamental aspects: conditions for rhythm generation, robust network designs and the periods of coupled oscillators. Consistently, these fundamental properties of circadian clocks also differ among Neurospora, Drosophila, and mammals depending on their key transcriptional repression mechanisms (Hill‐type repression or protein sequestration). Based on both theoretical and experimental studies, this review highlights the importance of careful modelling of transcriptional repression mechanisms in molecular circadian clocks.
Investigation of data forwarding schemes for network resiliency in POX software defined networking controller
Authors: Vaghani Raviraj , Lung Chung‐Horng
Published: April 2016

Software defined networking (SDN) is an emerging networking architectural framework which aims to provide the complete separation of data forwarding plane and control plane. The two main benefits of SDN are lower cost and improved management. OpenFlow is a well‐known architecture that facilitates SDN. The core idea of OpenFlow is to control the switches or routers through programming from the centralised controller. The connection reliability is a major concern for network service providers to meet quality of service requirements. Hence, an investigation of network resiliency is required for this new paradigm. The resiliency is the network's ability to survive against attacks and other component failures. This study investigates and compares different data forwarding algorithms currently supported by the POX OpenFlow controller standards for network protection and restoration. A thorough investigation of existing approaches or standards in SDN not only is essential for the research community to better understand the topic, but also plays a crucial role in realising or improving network resiliency or protection and restoration in practice. The authors also provide the extension of one of the components in POX for improvement. The restoration scheme in the current POX components as well as in the modified component is evaluated and compared.
Le comportement humain : première cause de complication en pratique médicale ?
Authors: Renouard Franck , Perrault-Pierre Edith
Published: April 2016

L’erreur médicale, et les complications qui en découlent, sont le plus souvent analysées sous leur aspect technique. L’influence du comportement humain n’est que très rarement évoquée dans l’étiologie première des évènements indésirables graves (EIG) en médecine. Quand la part humaine est mise en avant, c’est toujours de façon négative et critique : le fautif n’a pas appliqué les règles. Cependant, dans d’autres activités humaines à risques, telles que les industries aéronautique ou nucléaire, la place des comportements humains dans la survenue d’EIG a été étudiée et est aujourd’hui reconnue comme étant une des causes premières de complications et de problèmes. Des protocoles spécifiques ont été développés pour diminuer le nombre d’erreurs, ou pour en éliminer les conséquences quand des erreurs sont inévitablement produites. Cette approche nouvelle a considérablement diminué le taux d’accidents dans ces industries. Le but de cet article est de montrer qu’il est possible d’avoir la même approche en médecine et que l’introduction des facteurs humains dans l’analyse des pratiques médicales permet d’améliorer de façon significative la sécurité.
Échecs des ancrages osseux
Authors: Mer Grégoria , Brezulier Damien , Sorel Olivier
Published: April 2016

L’objectif de cet article est de lister les circonstances pouvant être à l’origine des
échecs dans l’utilisation des ancrages osseux temporaires en orthodontie et, par
conséquent, d’essayer de définir des critères de bon usage. Une revue de littérature et
l’analyse de cas cliniques ont servi de base à notre réflexion. Il en ressort qu’avec une
bonne connaissance des indications dans le choix des vis, de leur emplacement et des
protocoles de mise en place, associée à une analyse des mécaniques orthodontiques, les
ancrages osseux sont aujourd’hui un outil essentiel de l’orthodontiste, permettant des
mouvements autrefois irréalisables, ou stabilisant des mouvements parasites qui rendent
nos traitements plus fiables et plus efficients.
Chirurgie orthognathique : échecs chirurgicaux et
complications
Authors: Guyot Laurent
Published: April 2016

Les interventions de chirurgie orthognathique sont l’aboutissement d’une préparation
orthodontico-chirurgicale et préfigurent la fin du traitement pour le patient et sa
famille. Les principales interventions sont les ostéotomies maxillaires totales de Le Fort
I, les ostéotomies mandibulaires et les mentoplasties. Toutes ces interventions
nécessitent un environnement favorable et une technicité importante pour être menées à
bien. Comme tous les actes chirurgicaux, elles ne sont pas exemptes de complications per-
et post-opératoires pouvant entrer dans le cadre d’un aléa thérapeutique ou être fautives.
Quel qu’en soit le fondement, les complications chirurgicales peuvent entraîner des échecs
de la prise en charge de la dysmorphose. Comprendre ces complications et les analyser,
c’est déjà les prévenir et diminuer ses risques d’échec.
Échecs et rééducation linguale
Authors: Arnaud-Pellet Noëlle
Published: April 2016

Face à des dysfonctions ou parafonctions difficiles à éradiquer, la prise en charge
orthophonique est le plus souvent une alliée pour maîtriser l’environnement fonctionnel
des arcades dentaires. Cependant, certains facteurs allant de la psychologie à l’obstacle
ORL anatomique, de l’anomalie génétique au geste iatrogène, peuvent expliquer des
résultats parfois en demi-teinte de cette dernière. Parfois aussi, ce sont nos propres
résultats thérapeutiques qui sont mis en échec voire détruits par une langue récalcitrante
ou mal prise en considération. À travers une analyse des facteurs en jeu et la
présentation de cas cliniques, l’auteur propose une réflexion sur cet organe parfois
moteur, parfois destructeur des traitements.
Regards sur l’insuccès occlusal
Authors: Orthlieb Jean-Daniel , Giraudeau Anne , Jeanny Marion , Ré Jean-Philippe , Manière-Ezvan Armelle
Published: April 2016

Le succès est matérialisé par la pérennité d’un résultat thérapeutique esthétique et
fonctionnel. L’insuccès occlusal «post-orthodontique» pourrait se traduire par une
instabilité dentaire, un inconfort fonctionnel jusqu’à une plainte dentaire ou
musculo-articulaire. L’analyse de l’occlusion recherche les anomalies occlusales à
potentialités pathogènes répertoriées en anomalies de calage, anomalies de centrage,
anomalies de guidage. La grande capacité de tolérance de l’appareil manducateur rend
difficile la définition de la frontière entre physiologie et pathologie, mais il est
nécessaire de disposer de repères que l’on peut résumer ainsi : – calage : contact
occlusal de la cuspide mésio-linguale des premières molaires maxillaires (en classe I, II
ou III) et contacts occlusaux entre les canines antagonistes; – centrage : absence de
décentrage transversal entre OIM et ORC; – guidage : absence d’interférence postérieure,
absence d’interférence antérieure (verrouillage).
La chirurgie des cas de classe II et ses répercussions sur les
articulations temporo-mandibulaires
Authors: Manière-Ezvan Armelle , Savoldelli Charles , Busson Floriant , Oueiss Arlette , Orthlieb Jean-Daniel
Published: April 2016

Traditionnellement, ces interventions visent à corriger les décalages à responsabilité
mandibulaire par une avancée de la portion dentée de la mandibule après ostéotomie
mandibulaire. Au cours de la mise en place des plaques d’ostéosynthèses se décide la
position des condyles, déjà plus reculés de par la position allongée et l’atonie
musculaire du patient curarisé. Toutes les études montrent que la chirurgie « d’avancée
mandibulaire » entraîne un mouvement latéral et un recul des condyles, ainsi qu’un
mouvement de torque, tous préjudiciables aux condyles. Les facteurs prédisposant aux
atteintes dégénératives sont « le patient » : femme (entre 15 et 40 ans) hyperdivergente
ayant des antécédents de dysfonctionnement de l’appareil manducateur (DAM) et le geste
chirurgical de par la surcharge appliquée aux condyles. Quelles sont les solutions
possibles pour éviter les échecs ? Bien préparer le patient avant la chirurgie et effectuer
une simulation (sur articulateur), maîtriser la position du condyle pendant la chirurgie,
travailler avec les chirurgiens à la réalisation de système de stabilisation de la portion
condylienne (avec l’aide de la CAO), mettre en place rapidement une mobilisation de la
mandibule par kinésithérapie.
Les échecs orthodontiques dans le traitement des classes
II
Authors: Boileau Marie-José
Published: April 2016

Dans le traitement des cas de classe II, comme dans toutes les dysmorphoses, l’échec de
nos thérapeutiques peut concerner tout ou partie de nos objectifs de traitement :
occlusaux, fonctionnels et esthétiques. Après avoir précisé au travers de cas cliniques la
notion d’échec et les limites de l’acceptable dans ces différentes facettes, nous
essaierons de déterminer les causes principales de nos échecs afin de mieux les prévenir.
L’analyse de la littérature comme celle des cas cliniques montre que ceux-ci reposent le
plus souvent sur une erreur d’estimation de la quantité et de la direction de croissance
résiduelle, un mauvais contrôle du sens vertical, une prise en charge insuffisante des
problèmes fonctionnels, une position inadéquate des incisives maxillaires et
mandibulaires. À ces principales erreurs thérapeutiques s’ajoute l’insuffisance de
coopération des patients qu’il faut évaluer et entretenir afin de limiter échecs et
abandons de traitement.
An ultra-high temperature testing instrument under oxidation environment up to 1800 °C
Authors: Cheng Xiangmeng , Qu Zhaoliang , He Rujie , Ai Shigang , Zhang Rubing , Pei Yongmao , Fang Daining
Published: April 2016

A new testing instrument was developed to measure the high-temperature constitutive relation and strength of materials under an oxidative environment up to 1800 °C. A high temperature electric resistance furnace was designed to provide a uniform temperature environment for the mechanical testing, and the temperature could vary from room temperature (RT) to 1800 °C. A set of semi-connected grips was designed to reduce the stress. The deformation of the specimen gauge section was measured by a high temperature extensometer. The measured results were acceptable compared with the results from the strain gauge method. Meanwhile, tensile testing of alumina was carried out at RT and 800 °C, and the specimens showed brittle fracture as expected. The obtained Young’s modulus was in agreement with the reported value. In addition, tensile experiment of ZrB2–20%SiC ceramic was conducted at 1700 °C and the high-temperature tensile stress-strain curve was first obtained. Large plastic deformation up to 0.46% and the necking phenomenon were observed before the fracture of specimen. This instrument will provide a powerful research tool to study the high temperature mechanical property of materials under oxidation and is benefit for the engineering application of materials in aerospace field.
An integrated analog O/E/O link for multi-channel laser neurons
Authors: Nahmias Mitchell A. , Tait Alexander N. , Tolias Leonidas , Chang Matthew P. , Ferreira de Lima Thomas , Shastri Bhavin J. , Prucnal Paul R.
Published: April 2016

We demonstrate an analog O/E/O electronic link to allow integrated laser neurons to accept many distinguishable, high bandwidth input signals simultaneously. This device utilizes wavelength division multiplexing to achieve multi-channel fan-in, a photodetector to sum signals together, and a laser cavity to perform a nonlinear operation. Its speed outpaces accelerated-time neuromorphic electronics, and it represents a viable direction towards scalable networking approaches.
Generalization of the electronic susceptibility for arbitrary molecular geometries
Authors: Scherrer Arne , Dreßler Christian , Ahlert Paul , Sebastiani Daniel
Published: April 2016

We generalize the explicit representation of the electronic susceptibility χ[R](r, r′) for arbitrary molecular geometries R. The electronic susceptibility is a response function that yields the response of the molecular electronic charge density at linear order to an arbitrary external perturbation. We address the dependence of this response function on the molecular geometry. The explicit representation of the molecular geometry dependence is achieved by means of a Taylor expansion in the nuclear coordinates. Our approach relies on a recently developed low-rank representation of the response function χ[R](r, r′) which allows a highly condensed storage of the expansion and an efficient application within dynamical chemical environments. We illustrate the performance and accuracy of our scheme by computing the vibrationally induced variations of the response function of a water molecule and its resulting Raman spectrum.
The general theory of multistage geminate reactions of isolated pairs of reactants. III. Two-stage reversible dissociation in geminate reactionA+A↔C↔B+B
Authors: Kipriyanov Alexey A. , Kipriyanov Alexander A. , Doktorov Alexander B.
Published: April 2016

Specific two-stage reversible reaction A + A↔C↔B + B of the decay of species C reactants by two independent transition channels is considered on the basis of the general theory of multistage reactions of isolated pairs of reactants. It is assumed that at the initial instant of time, the reacting system contains only reactants C. The employed general approach has made it possible to consider, in the general case, the inhomogeneous initial distribution of reactants, and avoid application of model concepts of a reaction system structure (i.e., of the structure of reactants and their molecular mobility). Slowing of multistage reaction kinetics as compared to the kinetics of elementary stages is established and physically interpreted. To test approximations (point approximation) used to develop a universal kinetic law, a widely employed specific model of spherical particles with isotropic reactivity diffusing in solution is applied. With this particular model as an example, ultimate kinetics of chemical conversion of reactants is investigated. The question concerning the depths of chemical transformation at which long-term asymptotes are reached is studied.
First-principles investigations on ionization and thermal conductivity of polystyrene for inertial confinement fusion applications
Authors: Hu S. X. , Collins L. A. , Goncharov V. N. , Kress J. D. , McCrory R. L. , Skupsky S.
Published: April 2016

Using quantum molecular-dynamics (QMD) methods based on the density functional theory, we have performed first-principles investigations of the ionization and thermal conductivity of polystyrene (CH) over a wide range of plasma conditions (ρ = 0.5 to 100 g/cm3 and T = 15 625 to 500 000 K). The ionization data from orbital-free molecular-dynamics calculations have been fitted with a “Saha-type” model as a function of the CH plasma density and temperature, which gives an increasing ionization as the CH density increases even at low temperatures (T < 50 eV). The orbital-free molecular dynamics method is only used to gauge the average ionization behavior of CH under the average-atom model in conjunction with the pressure-matching mixing rule. The thermal conductivities (κQMD) of CH, derived directly from the Kohn–Sham molecular-dynamics calculations, are then analytically fitted with a generalized Coulomb logarithm [(lnΛ)QMD] over a wide range of plasma conditions. When compared with the traditional ionization and thermal conductivity models used in radiation–hydrodynamics codes for inertial confinement fusion simulations, the QMD results show a large difference in the low-temperature regime in which strong coupling and electron degeneracy play an essential role in determining plasma properties. Hydrodynamic simulations of cryogenic deuterium–tritium targets with CH ablators on OMEGA and the National Ignition Facility using the QMD-derived ionization and thermal conductivity of CH have predicted ∼20% variation in target performance in terms of hot-spot pressure and neutron yield (gain) with respect to traditional model simulations.
Deformation mechanisms of bent Si nanowires governed by the sign and magnitude of strain
Authors: Wang Lihua , Kong Deli , Xin Tianjiao , Shu Xinyu , Zheng Kun , Xiao Lirong , Sha Xuechao , Lu Yan , Zhang Ze , Han Xiaodong , Zou Jin
Published: April 2016

In this study, the deformation mechanisms of bent Si nanowires are investigated at the atomic scale with bending strain up to 12.8%. The sign and magnitude of the applied strain are found to govern their deformation mechanisms, in which the dislocation types (full or partial dislocations) can be affected by the sign (tensile or compressive) and magnitude of the applied strain. In the early stages of bending, plastic deformation is controlled by 60° full dislocations. As the bending increases, Lomer dislocations can be frequently observed. When the strain increases to a significant level, 90° partial dislocations induced from the tensile surfaces of the bent nanowires are observed. This study provides a deeper understanding of the effect of the sign and magnitude of the bending strain on the deformation mechanisms in bent Si nanowires.
Transparent ferrimagnetic semiconducting CuCr2O4 thin films by atomic layer deposition
Authors: Tripathi T. S. , Yadav C. S. , Karppinen M.
Published: April 2016

We report the magnetic and optical properties of CuCr2O4 thin films fabricated by atomic layer deposition (ALD) from Cu(thd)2, Cr(acac)3, and ozone; we deposit 200 nm thick films and anneal them at 700 °C in oxygen atmosphere to crystallize the spinel phase. A ferrimagnetic transition at 140 K and a direct bandgap of 1.36 eV are determined for the films from magnetic and UV-vis spectrophotometric measurements. Electrical transport measurements confirm the p-type semiconducting behavior of the films. As the ALD technique allows the deposition of conformal pin-hole-free coatings on complex 3D surfaces, our CuCr2O4 films are interesting material candidates for various frontier applications.
On the hole accelerator for III-nitride light-emitting diodes
Authors: Zhang Zi-Hui , Zhang Yonghui , Bi Wengang , Geng Chong , Xu Shu , Demir Hilmi Volkan , Sun Xiao Wei
Published: April 2016

In this work, we systematically conduct parametric studies revealing the sensitivity of the hole injection on the hole accelerator (a hole accelerator is made of the polarization mismatched p-electron blocking layer (EBL)/p-GaN/p-AlxGa1−xN heterojunction) with different designs, including the AlN composition in the p-AlxGa1−xN layer, and the thickness for the p-GaN layer and the p-AlxGa1−xN layer. According to our findings, the energy that the holes obtain does not monotonically increase as the AlN incorporation in the p-AlxGa1−xN layer increases. Meanwhile, with p-GaN layer or p-AlxGa1−xN layer thickening, the energy that the holes gain increases and then reaches a saturation level. Thus, the hole injection efficiency and the device efficiency are very sensitive to the p-EBL/p-GaN/p-AlxGa1−xN design, and the hole accelerator can effectively increase the hole injection if properly designed.
Effect of annealing conditions on the perpendicular magnetic anisotropy of Ta/CoFeB/MgO multilayers
Authors: Liu Yan , Hao Liang , Cao Jiangwei
Published: April 2016

Films with a structure of Ta (5 nm)/Co20Fe60B20 (0.8–1.5 nm)/MgO (1 nm)/Ta (1 nm) were deposited on Corning glass substrates by magnetron sputtering. The as-deposited films with CoFeB layer thickness from 0.8 to 1.3 nm show perpendicular magnetic anisotropy (PMA). After annealing at a proper temperature, the PMA of the films can be enhanced remarkably. A maximum effective anisotropy field of up to 9 kOe was obtained for 1.0- and 1.1-nm-thick CoFeB layers annealed at an optimum temperature of 300 °C. A 4-kOe magnetic field was applied during annealing to study its effect on the PMA of the CoFeB layers. The results confirmed that applying a perpendicular magnetic field during annealing did not improve the maximum PMA of the films, but it did enhance the PMA of the thinner films at a lower annealing temperature.
Memory for temporally dynamic scenes
Authors: Ferguson Ryan , Homa Donald , Ellis Derek
Published: April 2016

Recognition memory was investigated for individual frames extracted from temporally continuous, visually rich film segments of 5–15 min. Participants viewed a short clip from a film in either a coherent or a jumbled order, followed by a recognition test of studied frames. Foils came either from an earlier or a later part of the film (Experiment 1) or from deleted segments selected from random cuts of varying duration (0.5 to 30 s) within the film itself (Experiment 2). When the foils came from an earlier or later part of the film (Experiment 1), recognition was excellent, with the hit rate far exceeding the false-alarm rate (.78 vs. 18). In Experiment 2, recognition was far worse, with the hit rate (.76) exceeding the false-alarm rate only for foils drawn from the longest cuts (15 and 30 s) and matching the false-alarm rate for the 5 s segments. When the foils were drawn from the briefest cuts (0.5 and 1.0 s), the false-alarm rate exceeded the hit rate. Unexpectedly, jumbling had no effect on recognition in either experiment. These results are consistent with the view that memory for complex visually temporal events is excellent, with the integrity unperturbed by disruption of the global structure of the visual stream. Disruption of memory was observed only when foils were drawn from embedded segments of duration less than 5 s, an outcome consistent with the view that memory at these shortest durations are consolidated with expectations drawn from the previous stream.
CTCF: making the right connections
Authors: Ghirlando Rodolfo , Felsenfeld Gary
Published: April 2016

The role of the zinc finger protein CTCF in organizing the genome within the nucleus is now well established. Widely separated sites on DNA, occupied by both CTCF and the cohesin complex, make physical contacts that create large loop domains. Additional contacts between loci within those domains, often also mediated by CTCF, tend to be favored over contacts between loci in different domains. A large number of studies during the past 2 years have addressed the questions: How are these loops generated? What are the effects of disrupting them? Are there rules governing large-scale genome organization? It now appears that the strongest and evolutionarily most conserved of these CTCF interactions have specific rules for the orientation of the paired CTCF sites, implying the existence of a nonequilibrium mechanism of generation. Recent experiments that invert, delete, or inactivate one of a mating CTCF pair result in major changes in patterns of organization and gene expression in the surrounding regions. What remain to be determined are the detailed molecular mechanisms for re-establishing loop domains and maintaining them after replication and mitosis. As recently published data show, some mechanisms may involve interactions with noncoding RNAs as well as protein cofactors. Many CTCF sites are also involved in other functions such as modulation of RNA splicing and specific regulation of gene expression, and the relationship between these activities and loop formation is another unanswered question that should keep investigators occupied for some time.
SMASH, a fragmentation and sequencing method for genomic copy number analysis
Authors: Wang Zihua , Andrews Peter , Kendall Jude , Ma Beicong , Hakker Inessa , Rodgers Linda , Ronemus Michael , Wigler Michael , Levy Dan
Published: April 2016

Copy number variants (CNVs) underlie a significant amount of genetic diversity and disease. CNVs can be detected by a number of means, including chromosomal microarray analysis (CMA) and whole-genome sequencing (WGS), but these approaches suffer from either limited resolution (CMA) or are highly expensive for routine screening (both CMA and WGS). As an alternative, we have developed a next-generation sequencing-based method for CNV analysis termed SMASH, for short multiply aggregated sequence homologies. SMASH utilizes random fragmentation of input genomic DNA to create chimeric sequence reads, from which multiple mappable tags can be parsed using maximal almost-unique matches (MAMs). The SMASH tags are then binned and segmented, generating a profile of genomic copy number at the desired resolution. Because fewer reads are necessary relative to WGS to give accurate CNV data, SMASH libraries can be highly multiplexed, allowing large numbers of individuals to be analyzed at low cost. Increased genomic resolution can be achieved by sequencing to higher depth.
A flexible method for estimating the fraction of fitness influencing mutations from large sequencing data sets
Authors: Moon Sunjin , Akey Joshua M.
Published: April 2016

A continuing challenge in the analysis of massively large sequencing data sets is quantifying and interpreting non-neutrally evolving mutations. Here, we describe a flexible and robust approach based on the site frequency spectrum to estimate the fraction of deleterious and adaptive variants from large-scale sequencing data sets. We applied our method to approximately 1 million single nucleotide variants (SNVs) identified in high-coverage exome sequences of 6515 individuals. We estimate that the fraction of deleterious nonsynonymous SNVs is higher than previously reported; quantify the effects of genomic context, codon bias, chromatin accessibility, and number of protein–protein interactions on deleterious protein-coding SNVs; and identify pathways and networks that have likely been influenced by positive selection. Furthermore, we show that the fraction of deleterious nonsynonymous SNVs is significantly higher for Mendelian versus complex disease loci and in exons harboring dominant versus recessive Mendelian mutations. In summary, as genome-scale sequencing data accumulate in progressively larger sample sizes, our method will enable increasingly high-resolution inferences into the characteristics and determinants of non-neutral variation.
Neural-network-based containment control of nonlinear multi-agent systems under communication constraints
Authors: Ma Chao
Published: April 2016

Purpose

The purpose of this paper is to investigate the neural-network-based containment control of multi-agent systems with unknown nonlinear dynamics. Moreover, communication constraints are taken into account to reflect more realistic communication networks.

Design/methodology/approach

Based on the approximation property of the radial basis function neural networks, the control protocol for each agent is designed, where all the information is exchanged in the form of sampled data instead of ideal continuous-time communications.

Findings

By utilizing the Lyapunov stability theory and the Lyapunov–Krasovskii functional approach, sufficient conditions are developed to guarantee that all the followers can converge to the convex hull spanned by the stationary leaders.

Originality/value

As ideal continuous-time communications of the multi-agent systems are very difficult or even unavailable to achieve, the neural-network-based containment control of nonlinear multi-agent systems is solved under communication constraints. More precisely, sampled-data information is exchanged, which is more applicable and practical in the real-world applications.
Bio-inspired kinematical control of redundant robotic manipulators
Authors: Leylavi Shoushtari Ali , Mazzoleni Stefano , Dario Paolo
Published: April 2016

Purpose

This paper aims to propose an innovative kinematic control algorithm for redundant robotic manipulators. The algorithm takes advantage of a bio-inspired approach.

Design/methodology/approach

A simplified two-degree-of-freedom model is presented to handle kinematic redundancy in the x-y plane; an extension to three-dimensional tracking tasks is presented as well. A set of sample trajectories was used to evaluate the performances of the proposed algorithm.

Findings

The results from the simulations confirm the continuity and accuracy of generated joint profiles for given end-effector trajectories as well as algorithm robustness, singularity and self-collision avoidance.

Originality/value

This paper shows how to control a redundant robotic arm by applying human upper arm-inspired concept of inter-joint dependency.
Factors influence students' choice of accounting major in Cambodian universities
Authors: Tang Lim Chhoung , Seng Cheaseth
Published: April 2016

Purpose

The recent significant economic growth and development in Cambodia has created a growing demand for qualified and professional accountants. Despite such demand, there are still inadequate number of students enrolling in accounting major, which lefts the National Accounting Council (NAC), Kampucha Institute of Certified Public Accountants and Auditors (KICPAA), and academic institutions with question on how to develop strategies and plans for attracting students and in turn meeting the level required. This paper attempts to determine factors that influence Cambodian business students’ decision to choose accounting as a major for their tertiary education.

Design/methodology/approach

The paper hypothesizes that Guidance, Career Expectation, Perception, Personal Characteristic as factors that would influence students selection of accounting study. With a sample size of 240 business students, Turkey HSD Post Hoc Test and logistic regression methods are employed to ascertain the influential factors.

Findings

The results from ANOVA Turkey HSD Post Hoc Test showed that there is a statistically significant difference among universities with respect to Guidance, Career Expectation, and Personal Characteristic factor, but no significant difference was found among universities in terms of Perception factor. The logistic regression result indicated that students’ choice of accounting major has a positive and significant relationship with Guidance, Personal Characteristic factor, and age. Conversely, the results demonstrated that choice of accounting major has a negative but significant relationship with Career Expectation factor, and a negative but insignificant relationship with Perception factor. Finally, the results revealed a positive but insignificant relationship between accounting major and individual gender.

Originality/value

This paper contributes to the limited study on accounting education in Cambodia. Furthermore, it provides insights for the NAC and KICPAA and universities in Cambodia to develop strategies and plans to create a balance market of professional accountants.