bluuebunny/crossref_metadata_2025 huggingface dataset:
Rotordynamics modelling and analysis of high‐speed permanent magnet electrical machine rotors
Authors: Huang Ziyuan , Le Yun
Published: February 2018

For the high‐frequency permanent magnet electrical machine, a reasonable mechanical aspect design is crucial to meet its stability and reliability. This study focuses on the accurate modelling and analysis of the natural frequencies and modes of the rotor assembly for a designed and manufactured 100 kW 32,000 r/min motor. The influence of contact stiffness and friction on bending frequencies is analysed in detail. To obtain the accurate results of first two bending frequencies, on the basis of the finite‐element method, the optimisation method is carried out to acquire appropriate variables of the contact stiffness and friction. The optimised results show that the method proposed in this study can realise the accurate analysis of the rotor mode, which are verified by free–free modal testing of the rotor.
Distribution power factor monitoring in presence of high RES integration using a modified load encroachment technique
Authors: Mortazavi Hashem , Mehrjerdi Hasan , Saad Maarouf , Lefebvre Serge
Published: February 2018

This study presents a new approach in application of distance relay in distribution system. During the heavy load conditions, the load encroachment of impedance into the distance relay protection zones is a well‐known reason for distance relay mal‐operation. Therefore, all the modern digital distance relays are equipped with the load encroachment scheme. This study proposes the idea of using the load encroachment scheme of distance relay for monitoring purpose in the presence of renewable energy resources (RES) integration. Furthermore, it will be presented that based on the defined monitoring zones some alarms can be defined. The OpenDSS and Matlab software are used to test the effectiveness of the method with the IEEE 8500 node test feeder. The proposed method is tested with the unbalanced distribution system feeder loading and distributed model of solar generations. The dynamic performance of the proposed method is studied for on‐line power factor monitoring of the feeder with the sun irradiation dynamic. The results show the necessity of power factor monitoring in the distribution system with RES integration. In addition, the simplicity of the proposed method allows its easy application in the digital distance relay.
Performance bounds of joint angle‐frequency estimation based on spatio‐temporal co‐prime sampling
Authors: Lv Wanghan , Wang Huali , Mu Shanxiang , Luo Zhangkai
Published: February 2018

As known to us all, the Cramér–Rao bounds (CRBs) is a fundamental tool of performance assessment which expresses the lowest possible mean‐squared error among all unbiased methods. Although existing results display the closed‐form expression of CRBs for co‐prime array and give the conditions under which the CRBs exist, they are not applicable when the authors consider two or more kinds of parameters estimation in multi‐dimensional sparse sensing, especially parameters estimation in the spatio‐temporal coarray domain. The authors first derive the CRBs for joint angle‐frequency estimation based on spatio‐temporal co‐prime sampling and present the closed form of the joint CRBs. Then, the sufficient and necessary conditions under which the CRBs exist are explored. Finally, they discuss and analyse the asymptotic behaviour of the joint CRBs as a function of the number of snapshots and signal‐to‐noise ratio, respectively. The correctness of their results is demonstrated by simulation experiments.
Improving metal/n ‐Ge ohmic contact by inserting TiO2 deposited by PEALD
Authors: Zhang Yi , Liu Yan , Han Genquan , Liu Huan , Hao Yue
Published: February 2018

A simple method is used to improve metal/n ‐germanium (Ge) contact characteristics by inserting plasma‐enhanced atomic layer deposition (PEALD) deposited titanium dioxide (TiO2)/GeOx. Cross‐sectional transmission electron microscope results confirm the thickness of the 30 PEALD cycles TiO2/GeOx is 1.62/1.38 nm. By inserting 1.62/1.38 nm TiO2/GeOx between aluminium (Al) and n ‐Ge, current densities increased by about 1800 times at −0.1 V compared with contacts without insertion layer (IL). With IL, ρc of 9.52 × 10−3 Ω cm2 for Al/IL/n ‐Ge with an n ‐Ge concentration of 6 × 1016 cm−3 was achieved. ρc reduced by a factor 83 compared with no TiO2 IL, and it also shows 4.72 times reduction compared with ρc extracted from samples inserting thermal ALD‐deposited TiO2. X‐ray photoelectron spectroscopy (XPS) results shows that the valence state for GeOx was 3.682, thus Ge surface may be passivated. It was also determined by XPS that TiO2 was oxygen‐vacancies rich, which may dope TiO2 and may contribute to lower tunnelling resistance. All of the characteristics will be beneficial for low contact resistivity.
Solid-Liquid Extraction Kinetics of Total Phenolic Compounds (TPC) from Red Dates
Authors: Bee Lin Chua , Yen Leng Chen
Published: February 2018

Red dates are one of the most famous herbal plants in making traditional Chinese medicine. They contain large amount of bioactive compounds. The objectives of this research were to optimise the crude extract yield and total phenolic compounds (TPC) yield from red dates using response surface methodology (RSM) and model the extraction kinetics of TPC yield from red dates. Date fruits were dried in an oven under temperatures 50°C, 60°C, 70°C and 80°C until a constant weight was obtained. The optimum drying temperature was 60°C as it gave the highest crude extract yield and TPC yield. Besides that, single factor experiments were used to determine the optimum range of four extraction parameters which were: liquid-solid ratio (10-30 ml/g); ultrasonic power (70-90%); extraction temperature (50-70°C); and extraction time (40-60min). The optimum range of the four parameters were further optimised using the Box-Behken Design (BBD) of RSM. The extraction conditions that gave the highest crude extract yield and TPC yield were chosen. The optimum value for liquid-solid ratio, ultrasonic power, extraction temperature and extraction time were 30ml/g, 70%, 60°C and 60 min respectively. The two equations generated from RSM were reliable and can be used to predict the crude extract yield and TPC yield. The higher the extraction temperature, liquid-solid ratio, and extraction time and lower ultrasonic power, the higher the crude extract and TPC yield. Finally, the results of TPC yield versus time based on the optimum extraction parameters from RSM optimisation were fitted into three extraction kinetic models (Peleg’s model, Page’s model and Ponomaryov’s model). It was found that the most suitable kinetic model to represent the extraction process of TPC from red dates was Page’s model due to its coefficient of determination (R2) was the closest to unity, 0.9663 while its root mean square error (RMSE) was the closest to zero, 0.001534.
Mechanical Characterization of Zirconia Ceramic Composite
Authors: Jin Kelvin Chew Wai , Dickson Kam , Singh Ramesh
Published: February 2018

In this day and age, zirconia ceramics are used widely in the medical field as biomaterials for the replacement of damaged body parts. This is because zirconia is one of the closest replacements for bone tissue. However, there were a few cases regarding the failure of zirconia ceramic hip transplants. To overcome this issue, composite materials are being studied as they are able to combine different properties which are not present in a material. This study of Y-TZP/stainless steel 316 composite is carried out with the idea of providing a solution for failure of zirconia implants and also an improvement in biomaterials which will benefit the biomedical world. The study aims to determine the effects on how the increasing of stainless-steel content in the composite will affect the relative density, Vickers hardness, fracture toughness and ageing resistance of the Y-TZP/stainless steel 316 composite. To carry out the research, the composite samples were prepared by mixing the powder of each samples according to their determined content with ethanol. After the powders were mixed, the powders were then pressed, followed by undergoing a Cold Isostatic Press process (CIP) and then it underwent sintering at its determined temperature. After sintering, the samples underwent grinding and polishing before being ready for testing. The outcomes of the research showed that as the sintering temperature and the content of stainless-steel increase in the composite, the fracture toughness and ageing resistance improved while the Vickers hardness and relative density decreased.
Stabilising an Inverted Pendulum with PID Controller
Authors: Lim Yon Yaw , Hoo Choon Lih , Felicia Wong Yen Myan
Published: February 2018

Inverted pendulum is a system in which the centre of the mass is above the pivot point, where the mass can freely rotate. The inverted pendulum has a unique trait; it is unpredictable, non-linear and consists of multiple variables. Balancing by PID controller is a continuous process where it corrects the feedback system error from the difference between the measured value and the desired value. This research mainly focusses on balancing an inverted pendulum with reaction wheel. The research objectives are to construct a self-balanced inverted pendulum and using PID controller to control the stability of the pendulum. The PID configuration is then evaluated based on the response of the system. The idea is to use the reaction torque generated by the motor to counter balance the inverted pendulum. The factor which governs the amount of torque generated is the height of the pendulum and the mass of the wheel. To balance the pendulum, tuning the PID gain is essential. Proportional gain is tuned first to get oscillation, next is to tune the integral and derivative gain to get a smoother and quicker response. Idea is to get short settling time, and minimum overshoot percentage. Hypothesis is that higher proportional gain will give a faster response rate and the acceleration of the motor is the key on generating torque. A simulation of the pendulum falling is simulated and the results are recorded in term of the response of the pendulum against time. At initial point, proportional gain, integral gain and derivative gain are set to zero to validate the simulation. The finding in this research is that torque is generated by the acceleration of the reaction wheel. Higher acceleration gives a high torque. Others findings is the PID parameter; Proportional gain increases the response rate; Integral gain is used to eliminate steady state error; Derivative gain is used to lessen the overshoot.
The Application of Image Processing to Solve Occlusion Issue in Object Tracking
Authors: Cheong Yun Zhe , Chew Wei Jen
Published: February 2018

Object tracking is a computer vision field that involves identifying and tracking either a single or multiple objects in an environment. This is extremely useful to help observe the movements of the target object like people in the street or cars on the road. However, a common issue with tracking an object in an environment with many moving objects is occlusion. Occlusion can cause the system to lose track of the object being tracked or after overlapping, the wrong object will be tracked instead. In this paper, a system that is able to correctly track occluded objects is proposed. This system includes algorithms such as foreground object segmentation, colour tracking, object specification and occlusion handling. An input video is input to the system and every single frame of the video is analysed. The foreground objects are segmented with object segmentation algorithm and tracked with the colour tracking algorithm. An ID is assigned to each tracked object. Results obtained shows that the proposed system is able to continuously track an object and maintain the correct identity even after is has been occluded by another object.
Comparative Study between Planar and Bent Antenna Characterization
Authors: Zheng Tung Lau , Amouzed Mahdiraji Ghafour , Chia Ping Lee
Published: February 2018

Smaller designs of antenna usually implemented on Wi-Fi modules or navigation system devices which requires smaller bandwidth such as Planar Antenna. There are some antenna application requires bent antenna such as wearable UWB antenna but the substrate used will have some defects after bending and crumpling from time to time. What if the planar antenna is designed that it can be bent and the bending affects the impedance matching and shift in resonant frequency? So, this research aims to achieve the limitation of the planar antenna to be bent at certain angle and given frequency range (1-8 GHz). The planar antenna is designed in the Computer Simulation Technology (CST) Software and the proposed antenna is then bend in the simulation software. The analysis of comparative evaluation for both planar and bent antenna is carried out on different characteristics such as evaluation between S-Parameters & Frequency and evaluation between Voltage Standing Wavelength Ratio (VSWR) & Frequency. The behaviour of radiation pattern for both antennas can also be obtained in the CST simulation.
Proposed Framework of Hybrid Photovoltaic Thermal Systems to Ecotourism in Malaysia
Authors: Hajibeigy Mohammad Taghi , Aravind CV , Gangasa Walveka Rashmi
Published: February 2018

Ecotourism is widely recognized for its positive impacts to the environment. Ecotourism is defined as nature-based tourist experiences, which visitors travel to regions for the purpose of appreciating their natural beauty, relaxation and being harmonious with Mother Nature. Ecotourism probably had its foundations in the ethics of conservation, which can help maintain what’s left of nature and fosters environmental education. Employing the sustainable energy, paying more attention to the natural resources and developing existing natural resources will have a direct impact to healthier sustainable environment for the inhabitant. If not all, most of the ecotourism sites are located in the remote area in which to utilize electrical energy from the normal grid is difficult or very costly. On the irony, utilizing the conventional non-renewable energy have negative effect and ruins the ecotourism sites. Therefore, utilizing Hybrid Photovoltaic Thermal (PVT) systems is a fit alternative energy source to serve the limited energy demands of ecotourists sites. The amount of the energy production depends on the visitors’ capacity of the site. Since the rural area enjoys the cheap and large field, it is easier to plan and assemble the PVT systems to suffice the needed energy. In this research the sustainability of local environment along with the sustainable usage of energy were considered. This paper presents the sustainable energy usage of tourism in Malaysia and aims to address the impact of sustainable and non-sustainable on the rural area of ecotourism. This paper also addresses some of the emission, carbon reduction and climate change issues that the world is expected to meet soon.
Experiment and simulation study on relationship between diameter of high-pressure water abrasive jet nozzle and cutting capacity
Authors: Yu Xian Zhang , Nan Li , Hong Wang , Bin Bin Liu
Published: February 2018

High pressure water abrasive jet nozzle is key part of the particles acceleration. The diameter of nozzle has important effect for jet fluid. Through experiment and simulation explore the relationship between nozzle diameter and jet fluid cutting capacity. The result indicate: ①the cut depth and broad reduced in linearly relationship with the diameter of the jet nozzle. ②In same pressure, decrease the nozzle diameter will reduce the cutting ratio energy; ③The acceleration and attenuation of the nozzle axial flow in different diameters are basically consistent, The smaller nozzle diameter, The flow acceleration will slower, the attenuation will faster, the is velocity core segment will shorter and the cutting ability will lower;Consider from energy consumption, cutting efficiency and other factors, for common material cutting the nozzle preferred diameter is: 0.6~1.0mm, it’s unfavourable to select the 0.2mm diameter
Axial and Pressure Thrust Stiffness of Metal Bellows for Vibration Isolators
Authors: Ondřej Macháček , Michal Kubík , Zbyněk Strecker , Jakub Roupec , Petr Novák , Ivan Mazůrek
Published: February 2018

Metal bellows are used as a spring element and simultaneously as a container (shell) for a damping medium in vibration isolators, especially in applications where any leakage is inadmissible. Dynamic behaviour of these isolators is affected by axial stiffness of bellows and by a resistance against axial deformation of bellows filled with fluid, which is in this article called pressure thrust stiffness. A method of the pressure thrust stiffness determination is discussed in this study. The method uses FEM model, which has been verified by stiffness measurement of a chosen bellows. Consequently, the sensitivity analysis of bellows dimensions to axial and pressure thrust stiffness was performed to find a dimension parameter of bellows which allows to adjust the ratio between axial and pressure thrust stiffness. Sensitivity analysis shows that the stiffness ratio of metal bellows can be adjusted by two dimensional parameters - mean diameter of bellows and corrugation width.
Characteristic Analysis of longitudinal vibration Sucker Rod String With Variable Equivalent Stiffness
Authors: Lv Jian , Xing Mingming
Published: February 2018

Considering the influence of variable equivalent stiffness on system response, the equivalent stiffness is defined as a step function, and a mathematical model of nonlinear longitudinal vibration of sucker rod string (SRS) is built. The dynamic response under displacement and load force excitation is solved by fourth-order Runge-Kutta method with zero initial condition. The results show the steady-state responses under the displacement and load force excitation of different function forms are different. The response curves of both displacement and velocity under the displacement and load force excitation of cosine function form have larger fluctuation than it under the displacement and load force excitation of sine function form. Therefore, the characteristic analysis of SRS plays an important role in understanding the influence of the excitation form and sensitive parameters on steady response.
Structural Characterization of Hexagonal Braiding Architecture Aided by 3D Printing
Authors: Li Zhengning , Chen Ge , Lyu Haichen , Yuan Chenwang , Ko Frank
Published: February 2018

Hexagonal braiding method has the advantages of high shape compatibility, interlacing density and high volume fraction. Based on hexagonal braiding method, a hexagonal preform was braided. Then, by following the characteristics of repeatability and concentricity of hexagonal braided preform, the printed geometry structure was got in order to understand and optimize geometric structure to make it more compact like the braided geometric structure. Finally, the unit cells were defined with hexagonal prism to analyze the micro-geometric structure of hexagonal braided preform.
First integral method for non-linear differential equations with conformable derivative
Authors: Yépez-Martínez H. , Gómez-Aguilar J.F. , Atangana Abdon
Published: February 2018

In this paper, we present an analysis based on the first integral method in order to construct exact solutions of the nonlinear fractional partial differential equations (FPDE) described by beta-derivative. A general scheme to find the approximated solutions of the nonlinear FPDE is showed. The results obtained showed that the first integral method is an efficient technique for analytic treatment of nonlinear beta-derivative FPDE.
A highly efficient separation and physicochemical characteristics of saturated fatty acids from crude palm oil fatty acids mixture using methanol crystallisation method
Authors: Japir Abd Al-Wali , Salimon Jumat , Derawi Darfizzi , Yahaya Badrul Hisham , Bahadi Murad , Al-Shujaʼa Salah , Yusop Muhammad Rahimi
Published: February 2018

The objective of the current study was to separate saturated fatty acids (SFAs) from high free fatty acid crude palm oil fatty acid mixture using the methanol crystallisation method. The development of methanol crystallisation method procedure was based on various parameters. The fatty acid composition was determined by using gas chromatography-flame ionisation detector (GC-FID) as Fatty Acid Methyl Esters. The highest percentage of SFAs was more than 89% with the percentage yield of 48.9% under the optimal conditions of the fatty acids-to-methanol ratio of 1:15 (w/v), the crystallisation temperature of −15 °C, and the crystallisation time of 24 hours, respectively. After a double crystallisation, the composition of separated SFAs contains 90% of palmitic acid (C16:0) as a major component and 5.8% of stearic acid (C18:0), respectively. Moreover, almost 4.2% of oleic acid (C18:1) was observed in the saturated solid product. Based on the results, the use of methanol as a crystallisation solvent is recommended because of its high efficiency, low cost, stability, obtainability, and comparative ease of recovery.
Isolation, Synthesis, and Biological Activity of Quindoline, a Valuable­ Indoloquinoline Natural Product and Useful Key Intermediate­
Authors: Kaufman Teodoro , Méndez María , Bracca Andrea
Published: February 2018

Quindoline is one of the simplest naturally occurring monomeric indoloquinoline alkaloids. Chemists exhibited interest in this compound before it was isolated from a natural source. The different approaches toward the total synthesis of the natural product and its performance in various biological tests are discussed. Aspects related to the isolation of quindoline from different ethnomedicinally relevant plants around the world are also reviewed.

1 Introduction

2 Isolation and Biogenetic Considerations

3 Total Syntheses of Quindoline

3.1 Early Synthetic Studies

3.2 Syntheses from Benzenoids

3.3 Syntheses from Indoles

3.4 Syntheses from Quinolines

4 Biological Activity Studies

5 Conclusions
Erhebung von Ansätzen guter Praxis zur Integration Suchtkranker ins Erwerbsleben nach dem SGB II
Authors: Henke Jutta , Henkel Dieter , Nägele Barbara , Wagner Alexandra
Published: February 2018

Ziel der Studie Es wurde untersucht, welcher Umsetzungsstand bei der Integration Suchtkranker ins Erwerbsleben im Rahmen des SGB II unter dem Blickwinkel guter Praxis im Jahr 2016 erreicht wurde und ob sich die Praxis der Jobcenter seit der ersten Studie zu diesem Thema im Jahr 2009 weiterentwickelt hat.

Methode Im Zentrum stand eine bundesweite standardisierte Online-Befragung der Jobcenter, von denen sich 325 (80%) von insgesamt 408 beteiligten. Gegenstand der Befragung waren: die personelle Ausstattung der Jobcenter, suchtspezifische Schulung der Fachkräfte, Fachkonzeptentwicklung, Kooperation mit der Suchtberatung, Verfahren zum Erkennen von Suchtproblemen, Umgang mit Sanktionen, Netzwerke im regionalen sozialen Hilfesystem, Kooperation mit der Suchtrehabilitation, Maßnahmen zur Gesundheitsförderung, Beschäftigungs- und Qualifizierungsmaßnahmen und Integration der suchtkranken SGB II-Beziehenden in Arbeit.

Ergebnisse Im Vergleich zu 2009 lassen sich 2016 teils deutliche, teils leichte Fortschritte in der Praxis der Jobcenter erkennen. So fiel auch die Einschätzung der Integrationschancen in den ersten Arbeitsmarkt durch die Jobcenter-Fachkräfte deutlich weniger pessimistisch aus. Keine Verbesserungen sind eingetreten u. a. beim Erkennen von Suchtproblemen und der Bearbeitung der Schnittstelle zur Suchtrehabilitation. In die lokalen sozialen Netzwerke sind die Jobcenter dagegen inzwischen gut eingebunden und kooperieren mit vielen externen Akteurinnen und Akteuren.

Schlussfolgerungen Es besteht in vielerlei Hinsicht nach wie vor großer Handlungsbedarf.
Slow-wave metamaterial open panels for efficient reduction of low-frequency sound transmission
Authors: Yang Jieun , Lee Joong Seok , Lee Hyeong Rae , Kang Yeon June , Kim Yoon Young
Published: February 2018

Sound transmission reduction is typically governed by the mass law, requiring thicker panels to handle lower frequencies. When open holes must be inserted in panels for heat transfer, ventilation, or other purposes, the efficient reduction of sound transmission through holey panels becomes difficult, especially in the low-frequency ranges. Here, we propose slow-wave metamaterial open panels that can dramatically lower the working frequencies of sound transmission loss. Global resonances originating from slow waves realized by multiply inserted, elaborately designed subwavelength rigid partitions between two thin holey plates contribute to sound transmission reductions at lower frequencies. Owing to the dispersive characteristics of the present metamaterial panels, local resonances that trap sound in the partitions also occur at higher frequencies, exhibiting negative effective bulk moduli and zero effective velocities. As a result, low-frequency broadened sound transmission reduction is realized efficiently in the present metamaterial panels. The theoretical model of the proposed metamaterial open panels is derived using an effective medium approach and verified by numerical and experimental investigations.
Ab initio study of energy transfer rates and impact sensitivities of crystalline explosives
Authors: Bernstein Jonathan
Published: February 2018

Impact sensitivities of various crystalline explosives were predicted by means of plane wave-density functional theory calculations. Crystal structures and complete vibrational spectra of TATB, PETN, FOX7, TEX, 14DNI, and β-HMX molecular crystals were calculated. A correlation between the phonon-vibron coupling (which is proportionally related to the energy transfer rate between the phonon manifold and the intramolecular vibrational modes) and impact sensitivities of secondary explosives was found. We propose a method, based on ab initio calculations, for the evaluation of impact sensitivities, which consequently can assist in screening candidates for chemical synthesis of high energetic materials.
A molecular theory for predicting the thermodynamic efficiency of electrokinetic energy conversion in slit nanochannels
Authors: Hu Xiaoyu , Kong Xian , Lu Diannan , Wu Jianzhong
Published: February 2018

The classical density functional theory is incorporated with the Stokes equation to examine the thermodynamic efficiency of pressure-driven electrokinetic energy conversion in slit nanochannels. Different from previous mean-field predictions, but in good agreement with recent experiments, the molecular theory indicates that the thermodynamic efficiency may not be linearly correlated with the channel size or the electrolyte concentration. For a given electrolyte, an optimal slit nanochannel size and ion concentration can be identified to maximize both the electrical current and the thermodynamic efficiency. The optimal conditions are sensitive to a large number of parameters including ion diameters, valences, electrolyte concentration, channel size, and the valence- and size-asymmetry of oppositely charged ionic species. The theoretical results offer fresh insights into pressure-driven current generation processes and are helpful guidelines for the design of apparatus for the electrokinetic energy conversion.
Wakefield in solid state plasma with the ionic lattice force
Authors: Hakimi Sahel , Nguyen Tam , Farinella Deano , Lau Calvin K. , Wang Hsuan-Yu , Taborek Peter , Dollar Franklin , Tajima Toshiki
Published: February 2018

The advent of the path to a single cycle X-ray laser pulse via thin film compression and the relativistic compression enables laser wakefield acceleration in solid materials. We study the collective interaction of the X-ray laser pulse with the solid-state plasma, including ultrafast polariton effects, giving rise to TeV/cm wakefields with highly increased critical density. Our particle-in-cell computational analysis delineates wakefield effects and polariton dynamics. We show that a good quality wakefield can be excited even in the presence of the lattice force and the electron acceleration process is not influenced by polaritons. The applications and implications of the ultrafast wakefield and ultrafast plasmonics are discussed.
Extraction of sub-gap density of states via capacitance–voltage measurement for the erasing process in a TFT charge-trapping memory
Authors: Chiang Yen-Chang , Hsiao Yang-Hsuan , Li Jeng-Ting , Chen Jen-Sue
Published: February 2018

Charge-trapping memories (CTMs) based on zinc tin oxide (ZTO) semiconductor thin-film transistors (TFTs) can be programmed by a positive gate voltage and erased by a negative gate voltage in conjunction with light illumination. To understand the mechanism involved, the sub-gap density of states associated with ionized oxygen vacancies in the ZTO active layer is extracted from optical response capacitance–voltage (C–V) measurements. The corresponding energy states of ionized oxygen vacancies are observed below the conduction band minimum at approximately 0.5–1.0 eV. From a comparison of the fitted oxygen vacancy concentration in the CTM-TFT after the light-bias erasing operation, it is found that the pristine-erased device contains more oxygen vacancies than the program-erased device because the trapped electrons in the programmed device are pulled into the active layer and neutralized by the oxygen vacancies that are present there.
Pressure-induced transformations of multiferroic relaxor PbFe0.5Nb0.5O3
Authors: Basu Abhisek , Ahart Muhtar , Holtgrewe Nicholas , Lin Chuanlong , Hemley Russell J.
Published: February 2018

The effects of hydrostatic pressure at ambient temperature on the structural and dielectric properties of PbFe0.5Nb0.5O3 (PFN) were investigated using second harmonic generation (SHG) and powder x-ray diffraction measurements to 31 GPa. The results demonstrate that PFN undergoes a pressure-induced structural transition from the R3m ferroelectric to the R3¯m paraelectric phase. SHG measurements showed a continuous decrease in the signal with pressure and complete disappearance at 7.1 GPa. Effective nonlinear optical coefficients were determined from the SHG data, and their pressure behavior was used to infer the nature of the transition. The loss of the SHG signal is accompanied by drastic changes in line widths of Bragg reflections, but no discontinuous change in volume was observed. The pressure-volume data were fit to various equations of state, and a bulk modulus K0 = 136 (±2) GPa, bulk modulus pressure derivative K0′ = 4.0 (±0.2), and initial volume V0 = 64.5 (±0.1) Å3 were obtained.
Interface engineering of CsPbBr3/TiO2 heterostructure with enhanced optoelectronic properties for all-inorganic perovskite solar cells
Authors: Qian Chong-Xin , Deng Zun-Yi , Yang Kang , Feng Jiangshan , Wang Ming-Zi , Yang Zhou , Liu Shengzhong (Frank) , Feng Hong-Jian
Published: February 2018

Interface engineering has become a vital method in accelerating the development of perovskite solar cells in the past few years. To investigate the effect of different contacted surfaces of a light absorber with an electron transporting layer, TiO2, we synthesize CsPbBr3/TiO2 thin films with two different interfaces (CsBr/TiO2 and PbBr2/TiO2). Both interfacial heterostructures exhibit enhanced visible light absorption, and the CsBr/TiO2 thin film presents higher absorption than the PbBr2/TiO2 interface, which is attributed to the formation of interface states and the decreased interface bandgap. Furthermore, compared with the PbBr2/TiO2 interface, CsBr/TiO2 solar devices present larger output short circuit current and shorter photoluminescence decay time, which indicates that the CsBr contacting layer with TiO2 can better extract and separate the photo-induced carriers. The first-principles calculations confirm that, due to the existence of staggered gap (type II) offset junction and the interface states, the CsBr/TiO2 interface can more effectively separate the photo-induced carriers and thus drive the electron transfer from the CsPbBr3 perovskite layer to the TiO2 layer. These results may be beneficial to exploit the potential application of all-inorganic perovskite CsPbBr3-based solar cells through the interface engineering route.
Design and analysis of a novel dual-mass MEMS resonant output gyroscope
Authors: Gao Yang , Ding Xukai , Huang Libin , Li Hongsheng
Published: February 2018

This paper presents the design and analysis of a novel dual-mass microelectromechanical systems (MEMS) resonant output gyroscope (ROG), which can effectively eliminate the influence of common-mode disturbance, such as the linear acceleration, on the gyroscope working mode by the design of dual-mass form, as well as on the frequency outputs of the double-ended tuning fork (DETF) resonators by the differential arrangement. The concept of the ROG is introduced first. Then the dynamics of the gyroscope and the force-frequency characteristics of the DETF resonator are theoretically analyzed. By establishing the distribution coefficient of force and the reasonable equivalent of the force-frequency characteristics of the DETF resonator, the accurate expression of the device sensitivity is obtained. Based on the analysis results, the leverage mechanism and the DETF resonator are designed in detail. Then the configuration of the gyroscope, a dual-mass structure, is given. Finally, the validity of the analysis and design are verified by numerical simulations.
Hot spots based gold nanostar@SiO2@CdSe/ZnS quantum dots complex with strong fluorescence enhancement
Authors: Shan Feng , Su Dan , Li Wei , Hu Wei , Zhang Tong
Published: February 2018

In this paper, a novel gold nanostar (NS)@SiO2@CdSe/ZnS quantum dots (QDs) complex with plasmon-enhanced fluorescence synthesized using a step-by-step surface linkage method was presented. The gold NS was synthesized by the seed growth method. The synthesized gold NS with the apexes structure has a hot-spot effect due to the strong electric field distributed at its sharp apexes, which leads to a plasmon resonance enhancement. Because the distance between QDs and metal nanostructures can be precisely controlled by this method, the relationship between enhancement and distance was revealed. The thickness of SiO2 shell was also optimized and the optimum distance of about 21 nm was obtained. The highest fluorescence enhancement of 4.8-fold accompanied by a minimum fluorescence lifetime of 2.3 ns were achieved. This strong enhancement comes from the hot spots distributed at the sharp tip of our constructed nanostructure. Through the finite element method, we calculated the field distribution on the surface of NS and found that gold NS with the sharpest apexes exhibited the highest field enhancement, which matches well with our experiment result. This complex shows tremendous potential applications for liquid-dependent biometric imaging systems.
Viscous electron flow in mesoscopic two-dimensional electron gas
Authors: Gusev G. M. , Levin A. D. , Levinson E. V. , Bakarov A. K.
Published: February 2018

We report electrical and magneto transport measurements in mesoscopic size, two-dimensional (2D) electron gas in a GaAs quantum well. Remarkably, we find that the probe configuration and sample geometry strongly affects the temperature evolution of local resistance. We attribute all transport properties to the presence of hydrodynamic effects. Experimental results confirm the theoretically predicted significance of viscous flow in mesoscopic devices.
Two-dimensional free-surface flow under gravity: A new benchmark case for SPH method
Authors: Wu J. Z. , Fang L.
Published: February 2018

Currently there are few free-surface benchmark cases with analytical results for the Smoothed Particle Hydrodynamics (SPH) simulation. In the present contribution we introduce a two-dimensional free-surface flow under gravity, and obtain an analytical expression on the surface height difference and a theoretical estimation on the surface fractal dimension. They are preliminarily validated and supported by SPH calculations.
On concentration of positive ground states for the asymptotically linear fractional Schrödinger equation
Authors: Li Suhong , Li Jiongyue , Chen Yu
Published: February 2018

In this paper, we consider a nonlinear fractional Schrödinger equation with asymptotically linear growth. The existence and concentration phenomenon of semiclassical solutions are obtained under some conditions. The proof of main results is based on the variational methods and relies on an elementary idea of mountain pass arguments.
Effect of GPS sample interval and paddock size on estimates of distance travelled by grazing cattle in rangeland, Australia
Authors: McGavin Sharon L. , Bishop-Hurley Greg J. , Charmley Ed , Greenwood Paul L. , Callaghan Matthew J.
Published: February 2018

The distance travelled by an animal, when determined by using global positioning system (GPS) coordinates, is usually calculated assuming linear movement between the recorded coordinates. When using long sample intervals, some movement may be overlooked if linear movement between each recorded position is assumed, because of the tendency of livestock to move in meandering paths. Conversely, overestimation of the true distance travelled could occur with short sample intervals because of the accumulation of extra distance due to GPS measurement error. Data from 10 experiments were used to explore the effect of paddock size and GPS sampling rate on the calculation of distance travelled by free-ranging cattle. Shortening the sample interval increased apparent distance travelled according to a power function. As paddock size increased from <1 ha to >450 ha, distance travelled increased according to a logarithmic relationship; however, other variation between experiments could have affected these results. It was concluded that selecting an optimal GPS sampling interval is critical to accurately determining the distance travelled by free-ranging cattle.
Assessing host response to disease treatment: how chytrid-susceptible frogs react to increased water salinity
Authors: Klop-Toker Kaya L. , Valdez Jose W. , Stockwell Michelle P. , Edgar Matthew E. , Fardell Loren , Clulow Simon , Clulow John , Mahony Michael J.
Published: February 2018

Context The severity and prevalence of the amphibian fungal pathogen, Batrachochytrium dendrobatidis (Bd) is correlated with several environmental variables, including salinity, temperature, and moisture content, which influence the pathogen’s growth and survival. Habitats that contain these environmental variables at levels outside of those optimal for Bd growth and survival may facilitate the survival of susceptible host species. Therefore, manipulation of environmental salinity is a potential management strategy to help conserve Bd-susceptible species. However, host behaviour also influences disease dynamics, and the success of habitat manipulation programs depends on how hosts use this altered habitat. Aims To assess if the Bd-susceptible green and golden bell frog, Litoria aurea, will select waterbodies with a salinity increased to S=3; if this selection is affected by infection; and if a frog’s time in a waterbody of this salinity affects infection load or blood physiology. Methods We conducted a filmed choice experiment and a 3-year field study where infected and uninfected frogs could choose between fresh or saline waterbodies. Key results In both the laboratory experiment and field study, Bd-infected L. aurea spent a significantly greater amount of time in or closer to a waterbody than uninfected frogs. Experimentally infected frogs tended to prefer the saline water over fresh, but their choice of water usage did not differ statistically from uninfected frogs. In the field, frogs began to avoid ponds when salinities rose above S=5. Conclusions Because both wild and captive, and infected and uninfected L. aurea readily selected waterbodies with a salinity of S=3, this salinity could potentially be used as a passive method for reducing the severity of Bd when managing this species. However, further testing is needed to understand the efficacy of this treatment, and care must be taken to prevent salinities rising above S=5, because this level seems to produce an avoidance response and therefore may not be suitable in every location. Implications Manipulation of aquatic habitats may be a worthwhile focus for Bd management in habitats where water level fluctuations are minimal.
d
-Sedoheptulose-7-phosphate is a common precursor for the heptoses of septacidin and hygromycin B
Authors: Tang Wei , Guo Zhengyan , Cao Zhenju , Wang Min , Li Pengwei , Meng Xiangxi , Zhao Xuejin , Xie Zhoujie , Wang Wenzhao , Zhou Aihua , Lou Chunbo , Chen Yihua
Published: February 2018

Significance

Septacidin and its analogs are potential anticancer and pain-relief drugs. Hygromycin B is an anthelmintic agent practically used in swine and poultry farming. A common feature of these compounds is that they all have heptose moieties. Here we show that the heptoses of septacidin and hygromycin B are both derived from
d
-sedoheptulose-7-phosphate but are biosynthesized through different pathways. Septacidin producer, a gram-positive bacterium, shares the same ADP-heptose biosynthesis pathway with gram-negative bacterium lipopolysaccharide biosynthesis. These findings not only elucidate the biosynthesis mechanisms of septacidin and hygromycin B but enable opportunities for manipulation of their heptose moieties by combinatorial biosynthesis and for changing the structure of heptoses in gram-negative bacterium lipopolysaccharides.
Health effects of banning beehive coke ovens and implementation of the ban in China
Authors: Xu Yang , Shen Huizhong , Yun Xiao , Gao Fei , Chen Yilin , Li Bengang , Liu Junfeng , Ma Jianmin , Wang Xilong , Liu Xueping , Tian Chongguo , Xing Baoshan , Tao Shu
Published: February 2018

Significance

At present, many environmental laws and regulations are enforced in China, but they are often not well evaluated for their performance. In this study, the health effects of beehive coke oven operations, the ban of the ovens, and the slow implementation of the ban were assessed quantitatively, showing the importance of not only the legislation but also the implementation of the law. This study provides a good example that shows how environmental legislation and implementation can be evaluated to scientifically support decision making.
OCT4/POU5F1 is required for NANOG expression in bovine blastocysts
Authors: Simmet Kilian , Zakhartchenko Valeri , Philippou-Massier Julia , Blum Helmut , Klymiuk Nikolai , Wolf Eckhard
Published: February 2018

Significance

Studies of mammalian development are mostly performed in the mouse model, where reverse genetics is most advanced. Recent developments in gene editing, including CRISPR-Cas9, facilitated functional studies of specific genes in other mammalian species and revealed important differences (e.g., between human and murine development). In this study, we generated loss-of-function mutations of theOCT4gene in bovine fibroblasts and produced embryos by nuclear transfer cloning. We demonstrated that, similar to human development but in contrast to mouse development, OCT4 is required for maintaining NANOG-positive epiblast cells in the inner cell mass of blastocysts. Our study outlines a general strategy for dissecting the roles of specific genes in preimplantation development in domestic species.
Population trends in
Vermivora
warblers are linked to strong migratory connectivity
Authors: Kramer Gunnar R. , Andersen David E. , Buehler David A. , Wood Petra B. , Peterson Sean M. , Lehman Justin A. , Aldinger Kyle R. , Bulluck Lesley P. , Harding Sergio , Jones John A. , Loegering John P. , Smalling Curtis , Vallender Rachel , Streby Henry M.
Published: February 2018

Significance

Identifying drivers of population trends in migratory animals is difficult due to their reliance on different geographic regions throughout the annual cycle. Populations of Nearctic–Neotropical migratory birds are often thought to be limited by spatial variation in factors affecting reproduction and survival during the breeding season. We tracked individual songbirds from a two-species complex of New World warblers and discovered unequivocal evidence of a system in which strong associations between breeding areas and nonbreeding areas (i.e., migratory connectivity) is concordant with breeding population trends. The strong migratory connectivity we documented is associated with differential rates of land-use change in population-specific nonbreeding areas. Our results suggest that other migratory species with similar population trends may also exhibit strong migratory connectivity.
Optimal multiguidance integration in insect navigation
Authors: Hoinville Thierry , Wehner Rüdiger
Published: February 2018

Significance

The discovery of “place cells,” “grid cells,” and other spatial cells in the rodent’s forebrain has strengthened the idea that animals navigate their home range environments thanks to a “cognitive map.” Tiny-brained insects, like bees, are also thought to use such a centralized metric mental representation. However, downstream optimal combination of two decentralized guidance routines suffices to explain multiple experimental results obtained in bees and ants. We show that these insect navigators behave analogously to particles oriented by a global elastic force and local magnetic forces directed to the goal. As if equipped with both Ariadne’s thread and Hansel-and-Gretel’s pebbles, insects seem to know where to go rather than where they are on a map.
Changement grammatical et discursif en français multiculturel de la région parisienne
Authors: Secova Maria
Published: February 2018

Cet article cherche à comparer la variation et le changement dans deux domaines linguistiques, à savoir la grammaire et le discours. Il présente les résultats du projet « Multicultural London English – Multicultural Paris French » et s’interroge sur les différences dans l’usage des traits innovants et leur corrélation avec certaines catégories sociales. Du côté grammatical, la recherche se concentre en particulier sur l’usage des interrogatives indirectesin situtelles queje sais pas c’est quietje sais ça veut dire quoi,fréquemment utilisées à l’oral chez certains locuteurs. Du côté pragmatico-discursif, elle discute de l’utilisation des particules d’extension (et tout, et tout ça). L’étude révèle que la distribution des innovations discursives n’est pas la même que celle des innovations grammaticales, dont l’usage est davantage clivé en fonction des catégories sociales. L’article tente d’apporter des éclairages sur les processus de grammaticalisation et de changement, en s’interrogeant sur l’existence d’un français multiculturel typiquement « jeune » ou typiquement « parisien ».
Grammaticalization across Romance languages and the pace of language change
Authors: Lamiroy Béatrice , Pineda Anna
Published: February 2018

Grammaticalization across Romance languages and the pace of language change. The position of Catalan.

In several works on grammaticalization, one of the authors of this paper has established a grammaticalization cline which posits three major Romance languages: French at one extreme, Spanish at the other, and Italian in between (Lamiroy, 1999,2001,2003,2011,Lamiroy & De Mulder, 2011,De Mulder & Lamiroy, 2012,Van de Velde & Lamiroy, 2017). Our purpose is to place Catalan on this cline. To achieve our goal, we use data of Catalan related to several topics, viz. auxiliaries, past tense, existential sentences, mood and demonstratives. Catalan shows contradictory evidence: whereas the grammaticalization process in certain domains suggests that it parallels Spanish and Italian, in many others, it patterns with French. Thus the hypothesis for which we provide evidence here is the following cline : French > Catalan > Italian > Spanish.