bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of metal particle material on surface flashover performance of alumina-filled epoxy resin spacers in SF6/N2 mixtures under DC voltage
Authors: Wang Han , Xue Jianyi , Chen Junhong , Deng Junbo , Zhang Guanjun , Meng Shaoxin
Published: August 2019

When metal particle is attached on spacer surface, it will distort surface electric field and may reduce surface insulation level. Therefore, it is important to research the relationship between metal particle attachment and surface flashover property. In this study, the effect of metal particle materials on surface flashover performance of alumina-filled epoxy resin spacers in SF6/N2 mixtures is investigated. Three kinds of metal particle materials including copper, iron and aluminum are considered. The results reveal that, at low gas pressure or low surface electric field, the material of metal particle has no obvious effect on flashover voltage. At high gas pressure and high surface electric field, the flashover voltage is almost the same when the iron or aluminum particle is attached, which is lower than that with copper particle attached. It is revealed that at high pressure and high electric field, metal powders and vapor of micron size can be generated from the attached metal particle surface by electric field forces and Joule Heating Effect, which may be responsible for the difference in flashover voltage for different metal particle materials.
Fabrication of high thermal conductivity Cu/diamond composites at ambient temperature and pressure
Authors: Arai S. , Ueda M.
Published: August 2019

High thermal conductivity Cu/diamond composites were produced at ambient temperature and pressure using an electrodeposition technique, employing various diamond particle sizes in the range of 10 to 230 μm. The microstructures of the resulting composites were analyzed by scanning electron microscopy and their thermal conductivities were assessed using a Xenon flash instrument. The theoretical thermal conductivities of these materials were calculated based on the Hasselman-Johnson equation and compared with the experimentally determined values. The Cu/diamond composites produced in this work were found to exhibit compact textures without any gaps between the Cu matrix and the diamond particles, and the experimental thermal conductivities were in good agreement with the theoretical values. The specimen containing 61 vol.% of 230 μm diameter diamond particles had the highest conductivity of 662 W K-1 m-1, which is 1.6 times that of pure Cu (ca. 400 W K-1 m-1).
Noise analysis and active noise control strategy of transcranial magnetic stimulation device
Authors: Liu Chang , Ding Hongfa , Fang Xiao , He Zhou , Wang Zhixun
Published: August 2019

Transcranial magnetic stimulation (TMS) has been proved to be effective in the treatment of many psychiatric disorders, but the clicking noise produced by the large and short pulse current in the TMS coil may put negative effect to the hearing of patients. However, current researches on noise control of the TMS device are very limited. In this paper, by analyzing the actual noise signal of TMS, the mechanism of noise generation of the device is explained. According to the therapeutic schedule of TMS, an active noise control (ANC) strategy for TMS device with online identification, offline analysis, and real-time output is proposed. A finite element analysis model of noise propagation and noise control of the device is established. The strategy steps are as follows: the secondary pathway is constructed at first; during the first stimulation sequence, the coil noise received by the human ear is collected in real-time, and the noise is analyzed offline; the secondary signal is then produced to reduce the following noise in real-time. The simulation results show that the proposed ANC strategy for TMS can effectively reduce the noise with certain robustness.
An indoor location algorithm based on Kalman filter fusion of ultra-wide band and inertial measurement unit
Authors: Li Beibei , Hao Zhanjun , Dang Xiaochao
Published: August 2019

Indoor positioning technology has been widely used in today’s life, but due to the influence of multipath effect, the positioning signal is attenuated or even interrupted seriously, resulting in obvious reduction or even failure of positioning accuracy. Therefore, the emerging multi-sensor joint positioning has become the general trend of the development of positioning technology, in which Ultra-Wide Band (UWB) and Inertial Measurement Unit (IMU) have their own features in positioning and navigation. So this paper combines the advantages of UWB and IMU to achieve accurate positioning in complex environment. Firstly, the signal transmission law in complex environment is obtained by distinguishing Line of Sight (LOS) from NLOS (Non Line of Sight) environment. Secondly, the maximum likelihood estimation algorithm is used to eliminate the influence of NLOS on the transmitted signal, and then the extended Kalman filter information fusion strategy is used. The ranging information of UWB and the angle information of IMU are fused to realize the accurate positioning of UWB in complex environment. Finally, the experimental results show that the performance of the joint positioning proposed in this paper is obviously better than that of a single sensor compared with single UWB and single IMU positioning. It provides more solutions for accurate indoor positioning of multi-sensor fusion.
Turbulent flow and noise sources on a circular cylinder in the
critical regime
Authors: Zhang Chaofan , Moreau Stéphane , Sanjosé Marlène
Published: August 2019

The flow around a circular cylinder with long spanwise length has been investigated in the critical regime using a compressible wall-resolved Large Eddy Simulation (LES) for the first time. The flow at such a critical Reynolds number combines complex features: large favorable and adverse pressure gradient, separation and turbulence transition and flow reattachment. The results of the present simulation agree well with previous experimental and incompressible LES data, for the distribution of the mean wall-pressure coefficient that dominates the drag coefficient, and the skin-friction coefficient that illustrates the flow separation and reattachment behaviors. A weak reattachment is observed from the quasi-zero skin-friction in the reattachment region. A detailed study of the boundary-layer and shear-layer development around the cylinder with profiles of mean velocity and turbulence intensities confirms the transition, separation and reattachment behaviors shown by the skin-friction coefficient. The maximum tangential velocity and its location above the wall have also proven to be adequate measures of the edge velocity and associated boundary layer thickness. The Kelvin-Helmholtz instabilities have been observed in the shear layer and the ratio of the frequency of these instabilities and the fundamental vortex shedding frequency matches well with the existing scaling based on experimental data. The far-field noise obtained by both direct computation and acoustic analogy shows a dominant vortex shedding tone, but with additional broadband sources in the cylinder wake. These sound sources are evaluated from maps of filtered pressure signals and cross-correlation analysis of the pressure fluctuations around the cylinder and in the far-field.
New material generates spin and orbital angular momenta from a linearly polarized incident beam
Authors: Bandari Anashe
Published: August 2019

Researchers have developed an artificial material that converts linear polarization to circular polarization with both spin and orbital angular momenta in microwave beams.
New water tunnel provides nearly oceanic levels of turbulence
Authors: Liebendorfer Adam
Published: August 2019

The Vertical Octagonal Noncorrosive Stirred Energetic Turbulence tunnel looks to provide new understanding of bubble and droplet deformation in extremely turbulent environments.
Understanding Cell Interactions Using Modular Nanoparticle Libraries
Authors: Such Georgina K. , Johnston Angus P. R.
Published: August 2019

Nanoparticle delivery systems have significant potential to facilitate the delivery of novel therapeutics, such as proteins, DNA or small molecules. However, there are multiple biological barriers that need to be overcome to deliver the cargo in an active form. These challenges include evading clearance by the reticuloendothelial system, minimising adverse immune responses, targeting specific cells and tissues, and trafficking into the right compartment of the cell. In this account, we will discuss how nanoparticle structure can be tuned to optimise biological interactions and thus improve the ability of nanoparticles to overcome these barriers. The focus of this article will be on controlling cell targeting and trafficking within a cell, e.g. endosomal escape.
Soil physical attributes and organic matter accumulation under no-tillage systems in the Cerrado
Authors: Torres J. L. R. , Mazetto Júnior J. C. , Silva Júnior J. , Vieira D. M. S. , Souza Z. M. , Assis R. L. , Lemes E. M.
Published: August 2019

Soil management has a major effect on soil physical characteristics, and consequently on soil organic matter (SOM) content, which are important for the success of crop production. The aim of this study was to evaluate the soil physical attributes and the accumulation of SOM in no-tillage systems (NTS) with different periods of implantation in a conventional tillage area and to compare them with native forest (NF) in the Cerrado biome. The experiment was planned in a 3 × 4 factorial scheme, consisting of three soil treatments (NTS for 17 years (NTS17), NTS for 5 years (NTS5) and NF) and four soil depths (0–0.1, 0.1–0.2, 0.2–0.3 and 0.3–0.4 m), with a completely randomised design and four replicates. At deep soil layers (0.2–0.4 m) the NTS17 area had a greater soil density than the NTS5 and NF areas, and greater SOM compared with the NTS5 area. Soil macroporosity in the NTS5 area was below 10% at all soil depths evaluated. The NF area had the greatest total organic carbon content (1.39 dag kg–1), stock of carbon (16.63 Mg ha--1), amount of soil organic matter (28.66 Mg ha--1) and equivalent carbon credits (60.96 Mg ha–1). Carbon stocks were similar in the NTS areas in all soil depths evaluated. The results indicate that conventional tillage areas can be successfully recovered under the Cerrado edaphoclimatic conditions with the implantation of an NTS.
Energy metabolism controls phenotypes by protein efficiency and allocation
Authors: Chen Yu , Nielsen Jens
Published: August 2019

Significance

Organisms use the central carbon metabolism for both breakdown of substrate into biomass precursors and extraction of energy, making the pathways overlapping. We present a modeling concept that can decompose the overlapping pathways and hence account for protein cost for each of them. This enables comparisons between pathways within an organism or between organisms. Using this concept, we model energy metabolism for
Escherichia coli
and
Saccharomyces cerevisiae
, and accurately predict metabolic switches. Besides, we find that the total mass of the proteins involved in energy metabolism is conserved across conditions, which is simulated to correlate with ATP production rate in cells growing at unlimited conditions.
Influence of excess weight on lower‐extremity vertical stiffness and metabolic cost of walking
Authors: Bode Victoria G. , Croce Ronald V. , Quinn Timothy J. , Laroche Dain P.
Published: August 2019

The purpose was to test whether lower‐extremity vertical stiffness and gait mechanics explain differences in energy cost of walking (Cw) between individuals with normal weight (NW) and obesity (OB). Ten OB (33.1 ± 2.0 kg m−2) and 10 NW (24.2 ± 1.3 kg m−2) walked for six minutes on an instrumented treadmill at 1.25 m s−1 while Cw, lower‐extremity kinematics, and vertical stiffness (K vert) were measured. NW completed another trial with a loaded vest (NWL) to simulate the BMI of the obese group. Cw was 24% greater in OB (277.5 ± 45.3 J m−1) and 23% greater in NWL (272.7 ± 35.7 J m−1) than NW (211.0 ± 27.0 J m−1, P < 0.005). Mass‐specific Cw (Cwkg) wasn't different between conditions (P = 0.085). Lower‐extremity K vert was 40% higher in OB (32.7 ± 5.2 kN m−1) than NW (23.3 ± 4.7 kN m−1, P < 0.001), but neither was different from NWL (27.5 ± 3.4 kN m−1, P > 0.05). Mass‐specific K vert (P = 0.081) was similar across conditions. K vert was related to Cw (r = 0.55, P = 0.001). Cwkg wasn't different between NW or OB, but there was a negative correlation between BMI and Cwkg driven by lower Cwkg in NWL. Cw and K vert covaried in proportion to body mass, but mass‐specific K vert was unrelated to Cwkg. Mass‐specific K vert was lower in NWL than OB due to NWL's greater angle of attack, center of mass displacement, and joint range of motion.
Dissipative generation for steady-state entanglement of two transmons in circuit QED
Authors: He Shuang , Liu Dan , Li Ming-Hao
Published: August 2019

We present a dissipative scheme to generate an entangled steady-state between two superconducting transmon qutrits separately embedded in two coupled transmission line resonators in a circuit quantum electrodynamics (QED) setup. In our scheme, the resonant qutrit-resonator interaction and photon hopping between resonators jointly induce asymmetric energy gaps in the dressed state subspaces. The coherent driving fields induce the specific dressed state transition and the dissipative processes lead to the gradual accumulation in the population of target state, combination of both drives the system into a steady-state entanglement. Numerical simulation shows that the maximally entangled state can be produced with high fidelity and strong robustness against the cavity decay and qutrit decay, and no requirements for accurate time control. The scheme is achievable with the current experimental technologies.
Tunable coupling between Xmon qubit and coplanar waveguide resonator*
Authors: Li He-Kang , Li Ke-Min , Dong Hang , Guo Qiu-Jiang , Liu Wu-Xin , Wang Zhan , Wang Hao-Hua , Zheng Dong-Ning
Published: August 2019

Realization of a flexible and tunable coupling scheme among qubits is critical for scalable quantum information processing. Here, we design and characterize a tunable coupling element based on Josephson junction, which can be adapted to an all-to-all connected circuit architecture where multiple Xmon qubits couple to a common coplanar waveguide resonator. The coupling strength is experimentally verified to be adjustable from 0 MHz to about 40 MHz, and the qubit lifetime can still be up to

12

μ
s

in the presence of the coupling element.
Ellipticity-dependent ionization yield for noble atoms*
Authors: Delibašić Hristina , Petrović Violeta
Published: August 2019

The photoionization in the frame of the Ammosov–Delone–Krainov theory has been theoretically examined for noble gases, argon, krypton, and xenon, in an elliptically polarized laser field. We consider the intermediate range of the Keldysh parameter,

γ
∼
1

, and analyze the influence of shifted ionization potential and temporal profile to eliminate disagreement between theoretical and experimental findings. By including these effects in the ionization rates, we solve rate equations in order to determine an expression for the ionization yield. The use of modified ionization potential shows that the ionization yields will actually decrease below the values predicted by original (uncorrected) formulas. This paper will discuss the causes of this discrepancy.
Surface plasmon polaritons generated magneto–optical Kerr reversal in nanograting*
Authors: Chen Le-Yi , Zong Zhen-Xing , Gao Jin-Long , Tang Shao-Long , Du You-Wei
Published: August 2019

Controlling the phase of light in magnetoplasmonic structures is receiving increasing attention because of its already shown capability in ultrasensitive and label-free molecular-level detection. Magneto–optical Kerr reversal has been achieved and well explained in nanodisks by using the phase of localized plasmons. In this paper, we report that the Kerr reversal can also be produced by surface plasmon polaritons independently. We experimentally confirm this in Co and Ag/Co/Ag metal nanogratings, and can give a qualitative explanation that it is the charge accumulation at the interface between the grating surface and air that acts as the electromagnetic restoring force to contribute necessary additional phase for Kerr reversal. Our finding can enrich the means of designing and fabricating magneto–optical-based biochemical sensors.
Quasi-classical trajectory study of H+LiH (v = 0, 1, 2, j = 0)

→

Li+H2 reaction on a new global potential energy surface
Authors: Wang Yu-Liang , Su De-Zhi , Liu Cun-Hai , Li Hui
Published: August 2019

Quasi-classical trajectory (QCT) calculations are reported for the H+LiH (v = 0–2, j = 0)

→

Li+H2 reaction on a new ground electronic state global potential energy surface (PES) of the LiH2 system. Reaction probability and integral cross sections (ICSs) are calculated for collision energies in the range of 0 eV–0.5 eV. Reasonable agreement is found in the comparison between present results and previous available theoretical results. We carried out statistical analyses with all the trajectories and found two main distinct reaction mechanisms in the collision process, in which the stripping mechanism (i.e., without roaming process) is dominated over the collision energy range. The polarization dependent differential cross sections (PDDCSs) indicate that forward scattering dominates the reaction due to the dominated mechanism. Furthermore, the reactant vibration leads to a reduction of the reactivity because of the barrierless and attractive features of PES and mass combination of the system.
Interference effect of photoionization of hydrogen atoms by ultra-short and ultra-fast high-frequency chirped pulses*
Authors: Wang Ningyue , Liu Aihua
Published: August 2019

The photoionization of a hydrogen atom from its ground state with ultra-fast chirped pulses is investigated by numerically solving the time-dependent Schrödinger equation within length, velocity, and Kramers–Henneberger gauges. Converged results for all gauges for chirp-free pulses agree with the prediction of dynamic interference for ground state hydrogen atoms predicted recently by Jiang and Burgdörfer [Opt. Express 26, 19921 (2018)]. In addition, we investigated photoelectron spectra of hydrogen atoms by chirped laser pulses, and showed that dynamic interference effect will be weaken for pulses with increasing linear chirp. Our numerical results can be understood and discussed in terms of an interplay of photoelectron wavepackets from first and second halves of laser enevelop, including the ac Stark energy level shift of the photoelectron final state and atomic stabilization effect at ultra-high intensities.
Phase retrieval algorithm for optical information security*
Authors: Wang Shi-Qing , Meng Xiang-Feng , Wang Yu-Rong , Yin Yong-Kai , Yang Xiu-Lun
Published: August 2019

As a typical technology for optical encryption, phase retrieval algorithms have been widely used in optical information encryption and authentication systems. This paper presents three applications of two-dimensional (2D) phase retrieval for optical encryption and authentication: first, a hierarchical image encryption system, by which multiple images can be hidden into cascaded multiple phase masks; second, a multilevel image authentication system, which combines (t, n) threshold secret sharing (both t and n are positive integers, and

t
≤
n

) and phase retrieval, and provides both high-level and low-level authentication; and finally, a hierarchical multilevel authentication system that combines the secret sharing scheme based on basic vector operations and the phase retrieval, by which more certification images can be encoded into multiple cascaded phase masks of different hierarchical levels. These three phase retrieval algorithms can effectively illustrate phase-retrieval-based optical information security. The principles and features of each phase-retrieval-based optical security method are analyzed and discussed. It is hoped that this review will illustrate the current development of phase retrieval algorithms for optical information security and will also shed light on the future development of phase retrieval algorithms for optical information security.
Mask-based denoising scheme for ghost imaging*
Authors: Zhou Yang , Guo Shu-Xu , Zhong Fei , Zhang Tian
Published: August 2019

Ghost imaging (GI) is thought of as a promising imaging method in many areas. However, the main drawback of GI is the huge measurement data and low signal-to-noise ratio. In this paper, we propose a novel mask-based denoising scheme to improve the reconstruction quality of GI. We first design a mask through the maximum between-class variance (OTSU) method and construct the measurement matrix with speckle patterns. Then, the correlated noise in GI can be effectively suppressed by employing the mask. From the simulation and experimental results, we can conclude that our method has the ability to improve the imaging quality compared with traditional GI method.
Impeding anion exchange to improve composition stability of CsPbX3 (X = Cl, Br) nanocrystals through facilely fabricated Cs4Pb X6 shell*
Authors: Shen Zhaohui , Song Pengjie , Qiao Bo , Cao Jingyue , Bai Qiongyu , Song Dandan , Xu Zheng , Zhao Suling , Zhang Gaoqian , Wu Yuanjun
Published: August 2019

Inorganic lead halide perovskite nanocrystals (NCs) with superior photoelectric properties are expected to have excellent performance in many fields. However, the anion exchange changes their features and is unfavorable for their applications in many fields. Hence, impeding anion exchange is important for improving the composition stability of inorganic lead halide perovskite NCs. Herein, CsPbX
3 (X = Cl, Br) NCs are coated with Cs4PbX
6 shell to impede anion exchange and reduce anion mobility. The Cs4PbX
6 shell is facily fabricated on CsPbX
3 NCs through high temperature injection method. Anion exchange experiments demonstrate that the Cs4PbX
6 shell completely encapsulates CsPbX
3 NCs and greatly improves the composition stability of CsPbX
3 NCs. Moreover, our work also sheds light on the potential design approaches of various heterostructures to expand the application of CsPbM3 (M = Cl, Br, I) NCs.
Electronic and optical properties of GaN–MoS2 heterostructure from first-principles calculations*
Authors: Ren Dahua , Tan Xingyi , Zhang Teng , Zhang Yuan
Published: August 2019

Heterostructures (HSs) have attracted significant attention because of their interlayer van der Waals interactions. The electronic structures and optical properties of stacked GaN–MoS2 HSs under strain have been explored in this work using density functional theory. The results indicate that the direct band gap (1.95 eV) of the GaN–MoS2 HS is lower than the individual band gaps of both the GaN layer (3.48 eV) and the MoS2 layer (2.03 eV) based on HSE06 hybrid functional calculations. Specifically, the GaN–MoS2 HS is a typical type-II band HS semiconductor that provides an effective approach to enhance the charge separation efficiency for improved photocatalytic degradation activity and water splitting efficiency. Under tensile or compressive strain, the direct band gap of the GaN–MoS2 HS undergoes redshifts. Additionally, the GaN–MoS2 HS maintains its direct band gap semiconductor behavior even when the tensile or compressive strain reaches 5% or -5%. Therefore, the results reported above can be used to expand the application of GaN–MoS2 HSs to photovoltaic cells and photocatalysts.
Organic field-effect transistor floating-gate memory using polysilicon as charge trapping layer
Authors: Zhang Wen-Ting , Wang Fen-Xia , Li Yu-Miao , Guo Xiao-Xing , Yang Jian-Hong
Published: August 2019

In this study, we present an organic field-effect transistor floating-gate memory using polysilicon (poly-Si) as a charge trapping layer. The memory device is fabricated on a N+–Si/SiO2 substrate. Poly-Si, polymethylmethacrylate, and pentacene are used as a floating-gate layer, tunneling layer, and active layer, respectively. The device shows bidirectional storage characteristics under the action of programming/erasing (P/E) operation due to the supplied electrons and holes in the channel and the bidirectional charge trapping characteristic of the poly-Si floating-gate. The carrier mobility and switching current ratio (I
on/I
off ratio) of the device with a tunneling layer thickness of 85 nm are

0.01

cm

2

·

V

−
1

·

s

−
1

and 102, respectively. A large memory window of 9.28 V can be obtained under a P/E voltage of ±60 V.
Electronic structure from equivalent differential equations of Hartree–Fock equations
Authors: Lin Hai
Published: August 2019

A strict universal method of calculating the electronic structure of condensed matter from the Hartree–Fock equation is proposed. It is based on a partial differential equation (PDE) strictly equivalent to the Hartree–Fock equation, which is an integral–differential equation of fermion single-body wavefunctions. Although the maximum order of the differential operator in the Hartree–Fock equation is 2, the mathematical property of its integral kernel function can warrant the equation to be strictly equivalent to a 4th-order nonlinear partial differential equation of fermion single-body wavefunctions. This allows the electronic structure calculation to eliminate empirical and random choices of the starting trial wavefunction (which is inevitable for achieving rapid convergence with respect to iterative times, in the iterative method of studying integral–differential equations), and strictly relates the electronic structure to the space boundary conditions of the single-body wavefunction.
Model of output characteristics of giant magnetoresistance (GMR) multilayer sensor*
Authors: Zhang Jiao-Feng , Qian Zheng-Hong , Zhu Hua-Chen , Bai Ru , Zhu Jian-Guo
Published: August 2019

In this paper, the giant magnetoresistance (GMR) multilayer sensor is fabricated with a Wheatstone bridge, and it exhibits excellent performance with a sensitivity of 2.8349 mV/(V/Oe) (

1

Oe
=
79.5775

A
·

m

−
1

) and a saturation field of 26 Oe along the sensitive axis. The GMR sensor is also characterized in a high magnetic field. The sensitivity decreases from 2.8349 mV/(V/Oe) at an angle of 0° to 0.0175 mV/(V/Oe) at an angle of 90°. Then, the sensor is placed in a series of rotating magnetic fields. We propose a model to express the output characteristics of the GMR multilayer sensor. The transfer curves of the sensor can be shown as two exactly symmetrical circles with an increasing radius when the magnetic field increases. The experimental results are consistent with the simulation results of the model. The advantage of this model is that it is simpler and more intuitive.
Monolithic semi-polar (

1

1

¯

01

) InGaN/GaN near white light-emitting diodes on micro-striped Si (100) substrate*
Authors: Wang Qi , Yuan Guo-Dong , Liu Wen-Qiang , Zhao Shuai , Zhang Lu , Liu Zhi-Qiang , Wang Jun-Xi , Li Jin-Min
Published: August 2019

The epitaxial growth of novel GaN-based light-emitting diode (LED) on Si (100) substrate has proved challenging. Here in this work, we investigate a monolithic phosphor-free semi-polar InGaN/GaN near white light-emitting diode, which is formed on a micro-striped Si (100) substrate by metal organic chemical vapor deposition. By controlling the size of micro-stripe, InGaN/GaN multiple quantum wells (MQWs) with different well widths are grown on semi-polar (

1

1

¯

01

) planes. Besides, indium-rich quantum dots are observed in InGaN wells by transmission electron microscopy, which is caused by indium phase separation. Due to the different widths of MQWs and indium phase separation, the indium content changes from the center to the side of the micro-stripe. Various indium content provides the wideband emission. This unique property allows the semipolar InGaN/GaN MQWs to emit wideband light, leading to the near white light emission.
Analysis of elliptical thermal cloak based on entropy generation and entransy dissipation approach*
Authors: Wang Meng , Huang Shiyao , Hu Run , Luo Xiaobing
Published: August 2019

In this work, we designed the elliptical thermal cloak based on the transformation thermotics. The local entropy generation rate distribution and entransy dissipation rate distribution were obtained, and the total entropy generation and entransy dissipation of different types of elliptical cloaks were evaluated. We used entropy generation approach and entransy dissipation approach to evaluate the performance of the thermal cloak, and heat dissipation analysis was carried out for models with different parameters. Finally, the optimized elliptical thermal cloak with minimum entropy generation and minimum entransy dissipation is found, and some suggestions on optimizing the structure of elliptical thermal cloak were given.
Structural model of substitutional sulfur in diamond*
Authors: Yu Hongyu , Gao Nan , Li Hongdong , Huang Xuri , Duan Defang , Bao Kuo , Zhu Mingfeng , Liu Bingbing , Cui Tian
Published: August 2019

Based on ab initio calculations, it is found that the donor center of substitutional sulfur (S) in diamond with

C

2
v

symmetry is more stable than that with

C

3
v

symmetry, which is different from previous reports in literature. The energy difference of

C

2
v

and

C

3
v

structures is qualitatively affected by the supercell size, and the 216-atom supercell could be proposed as the minimum to obtain stable configuration of substitutional S in diamond. Using supercells of up to 512 atoms, the donor level of substitutional S with

C

2
v

symmetry is deep.
Improving robustness of GGNMOS with P-base layer for electrostatic discharge protection in 0.5-

μ
m

BCD process
Authors: Hou Fei , Chen Ruibo , Du Feibo , Liu Jizhi , Liu Zhiwei , J Liou Juin
Published: August 2019

Gate-grounded N-channel MOSFET (GGNMOS) has been extensively used for on-chip electrostatic discharge (ESD) protection. However, the ESD performance of the conventional GGNMOS is significantly degraded by the current crowding effect. In this paper, an enhanced GGNMOS with P-base layer (PB-NMOS) are proposed to improve the ESD robustness in BCD process without the increase in layout area or additional layer. TCAD simulations are carried out to explain the underlying mechanisms of that utilizing the P-base layer can effectively restrain the current crowing effect in proposed devices. All devices are fabricated in a 0.5-

μ
m

BCD process and measured using the transmission line pulsing (TLP) tester. Compared with the conventional GGNMOS, the proposed PB-NMOS devices offer a higher failure current than its conventional counterpart, which can be increased by 15.38%. Furthermore, the PB-NMOS_type3 possesses a considerably lower trigger voltage than the conventional GGNMOS to protect core circuit effectively.
New design of ferroelectric solar cell combined with luminescent solar concentrator*
Authors: Latreche Slimane , Fathi Mohamed , Kadri Abderrahmane
Published: August 2019

A new transparent photovoltaic panel composed of a luminescent solar concentrator and Al/BaTiO3/ZnO/Pt ferroelectric solar cells is presented, in which a portion of the incoming solar illumination is converted by the fluorophores to ultraviolet (UV) light which is then absorbed by ZnO. Firstly, the solar cells are simulated using Atlas–Silvaco. Then, the panel is modelled based on the obtained solar cell characteristics. This panel would be of great importance for building integrated photovoltaics domain because of its high transparency.
Techniques of microwave permeability characterization for thin films*
Authors: Li Xi-Ling , Wang Jian-Bo , Chai Guo-Zhi
Published: August 2019

We review the microwave methods to characterize the material properties, including the established and the emerging techniques in material characterization, especially the permeability spectra of the magnetic thin films. Almost all aspects of the microwave techniques for characterizing the permeability of thin films at microwave frequencies, including the new methods developed by our group, are presented. Firstly, the introduction part is presented. Secondly, the coaxial-line with transmission/reflection methods and the pickup coil with electromagnetic induction method are presented. Thirdly, the most widely used shorted microstrip technique is discussed in detail by the equivalent circuit method, transmission line method, and electromagnetic induction method. Fourthly, the coplanar waveguide method and the near-field probe method are also introduced. Finally, the high temperature permeability characterization by using the shorted microstrip line, the near-field microwave probe, and the shorted microstrip line probe are described in detail. This paper may be useful for researchers or engineers who will build up such measurement fixture to make full use of the existing methods or to develop original methods to meet the requirements for ever-rising measurements.
Effect of AlN coating on hydrogen permeability and surface structure of VT6 alloy by vacuum arc ion plating*
Authors: Ding Zi-Yi
Published: August 2019

We study the absorption of hydrogen of metal by the permeability method. With the help of the gas reaction controller (GRC), the absorptive capacity of hydrogen, which is a function of time, temperature and pressure, can be recorded. The effect of the performance of the hydrogen permeability of AlN coating on the titanium alloy surface structure is studied. In the research, the AlN is selected to be added to the titanium alloy sample VT6, and the properties of the titanium alloy are investigated, and the hydrogen absorption rate of the coating is calculated by performing the hydrogen saturation of the test sample. The results show that under 600 °C the AlN film reduces the hydrogen absorption rate of titanium alloy and improves the surface properties of VT6 alloy.
Reliability of Loading Rate in Gait Analysis
Authors: Abolins V , Nesenbergs K , Bernans E
Published: August 2019

Loading rate is an important parameter of running gait as it is commonly associated with increased risk of injury. In this paper we show, that most of the research related to calculating loading rate values from ground reaction force data cannot be directly compared, as the absolute loading rate values and the related first impact peak location and height are highly dependent on the filtering method used, cut-off frequency selected as well as loading rate calculation method selected. The results are based on running trial data from non-forefoot striking long distance runners gathered by the authors.
Structural reliability and performance evaluation of symmetric and asymmetric multi-storey buildings subjected to lateral wind forces
Authors: Kewalramani M A , Syed Z I , Almustafa M S , Hassouna M S
Published: August 2019

Lately there has been enormous enhancement of buildings architecturally. Most of the buildings are designed and constructed with diverse variations like soft–storey, torsional irregularity, asymmetrical layout of walls, irregularities in plan and elevation and thus overall building configuration. Any such variation result in challenging implications in terms of structural reliability and appropriate design of structural members. Calculation of lateral forces on these structures is an essential process in case of high– rise structures and structural performance of these aesthetically appealing asymmetric irregular shaped buildings especially when subjected to heavy wind forces need to be carefully assessed by structural engineers. The present work intends at performance evaluation by studying structural reliability of symmetrical and asymmetrical regular square, L, C and T–shaped reinforced concrete multi–storey buildings subjected to wind loads. The wind load analysis on these buildings is carried out in line with ASCE 7–10 design code. A comparative evaluation of critical parameters like fundamental period, natural and circular frequency of building, maximum joint displacement, storey drift ratio, inter–storey drift, internal forces in structural members, storey response and storey stiffness determines that difference in shape of a particular storey (or building) influence overall structural performance of building.
Medical Device Integrated System Accelerated Life Testing
Authors: Atua Khaled , Baniasad Saeid
Published: August 2019

This paper defines the accelerated life test design and technique to evaluate medical device system reliability. The proposed method includes developing system functional diagram to capture the overall ecosystem of the device and all control and noise factors that affect device performance. The test simulates real life therapy level stresses including temperature, patient use, disposable setting, power source alterations, medical prescription and duty cycle. These operation elements are used at different rates to balance the aging of different subsystems and rate of different failure mechanisms. The sample size of the test units is determined based on minimizing the overestimation error of the Mean Time Between Failure (MTBF) value. All observed events, and failures are categorized, and identified as failure per the expected complaint handling systems in real life. The test/tester setup errors and customer errors can also be tracked separately in the test and a mechanism of feeding back to human factors analysis, manufacturing, and service departments are identified to help optimize and inform product design and sustaining engineering activities. Test results and findings are to be compared to field data and benchmarked against a predicted number of failures based on the reliability requirements analysis established prior to product release. Test data and performance parameters are to be tracked and used to establish and optimize proactive and predictive maintenance interval and strategies for limited life and degrading components. Finally, a standardized testing method is to be revised based on lessons learned, and to be generalized for future product tests.
Extended Order High Gain Observer Based Stabilization of 2 DOF Pan Tilt Platform for Aerial Imaging System
Authors: Altaf O , Malik F M , Azim R A , Hussain S , Ahmad N
Published: August 2019

Aerial imaging systems are mounted on two axis serial robotic manipulators with high powered pan and tilt actuations, known as a Gimbal. The angular displacement of the gimbal is measured through very high precision sensors, typically shaft encoders with high PPR specifications. The purpose of the gimbal is to keep the orientation of the payload towards the target irrespective of the displacement of the UAV (unmanned aerial vehicle) and any other vibrations/disturbances that might be introduced into the system. Because of 2-DOF (degrees of freedom) dynamical model of the gimbal, frictional force, noise, cable restraint, disturbances from the external environment along with the motions of the vehicle’s body (as a result of manoeuvring or vibration), the spotting and tracking accuracy of the gimbal platform system may significantly degrade. The nature of these redundant disturbances is mostly of nonlinear nature and their modelling is a difficult task as they keep on changing. In order to cancel out these redundant disturbances and uncertainties, extended order high gain observer (EHGO) based feedback linearization control is used and extensive simulations are performed to show the comparison of tracking control without EHGO and after augmenting EHGO.
A Fault Inference Method under Uncertainty: Case Study on Crankshafts in Fracturing Pumps
Authors: Zhang X , Zhang L B , Hu J Q
Published: August 2019

Crankshaft is a pivotal mechanical unit in the power-end system of a fracturing pump and its fault inference could facilitate optimal condition-based maintenance. Fracturing pumps are equipped with advanced instrumentation systems able to acquire vibration information for crankshaft fault analysis, but there exist complex uncertain dependences between faults and symptoms as well as incomplete symptom information, further increasing the difficulty of fault inference by operators. To achieve effective fault inference in the case of uncertain or incomplete diagnosis evidences, a Bayesian network-based fault inference method for crankshafts is proposed in this article. The approach can be utilized to implement cause inference and diagnosis inference by incorporating cause nodes, fault nodes and symptom nodes into a Bayesian network (BN) model. The application of the presented approach in fault inference of crankshafts indicates its strong inference capability under uncertainty. The results from the presented BN model may offer a useful aid to repairers in their maintenance decision-making processes.
Research on Antenna Cabin Structure Optimization Based on Response Surface and Multi-island Genetic Algorithm
Authors: Weimin Sun , Weizhong Cao , Yeqing Gu
Published: August 2019

This paper focuses on the characteristics of high efficiency and high accuracy in the optimization design of the antenna bay structure. The polynomial response surface model is used to replace the computationally intensive target characteristic analysis model in the original genetic algorithm and a multi-island genetic algorithm is combined with the sequential quadratic programming. In this method, the square steel structure of the antenna module is optimized, which not only ensures the search for the global optimal solution, but also improves the calculation efficiency. The optimized results meet the rigid strength requirements of the antenna module under working wind load, and the weight of the antenna module is reduced by 33.5%, which greatly saves costs.
Study on Stress Properties of Iron Based Cladding Coating under Bending Load
Authors: Xu Lifu , Li Chao , Huang Shutao , Song Bo
Published: August 2019

The finite element analysis was employed to investigate equivalent stress characteristics of iron based cladding coating and substrate, and a three-point bending simulation test was carried out. The coating was set separately on the sides of stretchand press, the distribution and change rule of equivalent stress for different coating thickness were obtained through analyzing the stress state of thecoating/substrate system and influence of coating thickness on the interfacial stress. The results show that the maximum stress of the coating/substrate system appears on the coating surface under the bending load; the thicker the coating, the higher the maximum equivalent stress of the coating/substrate system under the same press amount of the punch head.
Experimental Study on Key Design Parameters of Cast-in-situ Pile Foundation in Permafrost Regions
Authors: Ji Yanjun , Hu Yupu , Jin Long , Luo Tao
Published: August 2019

The freezing strength of pile foundation in contact with permafrost is the key parameter for calculating the bearing capacity and pull-out stability of foundation. The thermal physical parameters of concrete before initial setting under various conditions were measured by a thermal conductivity meter based on the transient method. The effects of water binder ratio and pouring temperature on the thermal physical parameters were analyzed. The results show that the ratio of water to binder increases from 0.4 to 0.6, the thermal conductivity and thermal diffusivity decrease and the specific heat increases correspondingly; the thermal conductivity is negatively correlated with the pouring temperature, while the specific heat and thermal diffusivity are not significantly correlated with the pouring temperature. Based on the above research results, it is suggested that the water binder ratio of 0.4-0.45 and the pouring temperature of 5-10°C should be adopted in the design of cast-in-place piles in permafrost regions.
Mechanical Analysis of TRB Transition Region
Authors: Fu Xiujuan , Yu Ge , Zhao Yan , Lu Jiang , Yu Yuehong
Published: August 2019

In this paper, the mechanical properties of Tailor Rolled Blank (TRB) transition region was investigated By establishing a true stress-strain constitutive model of the TRB transition region. Firstly, the stress-strain curve obtained by uniaxial tensile test of 1mm, 2mm thick plates is subjected to regression analysis. Based on Ludwig equation, the true stress-strain constitutive equations of 1mm and 2mm thick plates were obtained. Then, The true stress-strain constitutive equation of TRB transition region was established by interpolation method combined with 1mm, 2mm thick plate constitutive equation, volume invariance theory and Von-Mises equivalent strain.Finally, the accuracy of the model is verified by simulation and experimental comparison. The results show: A new constitutive model of TRB was established, which is well responsed to the mechanical properties of the transition region.
Study on the Factors Influencing of the Anti-aging Behaviour in Different Antioxidants/Butadiene Rubber
Authors: Li Guangjuan , Song Meng , Zheng Wei , Lu Ling , Zhang Sidian , Wu Sizhu
Published: August 2019

In this work, antioxidants 6PPD, 2246, and MB were used to study anti-aging factors in butadiene rubber (BR) composites. Combined with molecular simulations, the four factors were proposed and quantified. Chemically, the free energy of the hydrogen dissociation reaction for the different structures was calculated by quantum mechanics (QM) methods. Meanwhile, the physical factors were characterized by molecular dynamics (MD) simulations. To rank the relative importance of the four factors, we employed the gray relational analysis (GRA) method. It was obtained that the free energy for the hydrogen dissociation reaction and the permeability for O2 should be given priority.
Study on Multi-steps Dynamic Compression Deformation Behavior of Ti-5.5Al Alloy
Authors: Luo Yumeng
Published: August 2019

The microstructure evolution in a specific area with typical characteristics of the Ti-5.5Al alloy was studied under multi-steps dynamic compression condition at a strain rate of 4000s-1 by EBSD/SEM method. Both twinning and dislocation movement were proved to be the deformation mechanism. However, the dominant deformation mechanism was greatly influenced by strain. During the strain level from 0 to 0.05, the most important deformation mechanism of Ti-5.5Al alloy was dislocation slip. During the deformation process of strain 0.05 to 0.10, the main deformation mechanisms were the {1012} of twin and dislocation movement. The rapid expansion of existing twins causes significant changes of texture. During a strain level from 0.10 to 0.15, the main deformation mechanism was twinning, while the dislocation movement dominated the deformation when the strain increased from 0.15 to 0.20. Besides, dislocation was proved to active prior to twinning.
Effects of Mo Element on Microstructure and Mechanical Properties of CoCrFeMnNi High Entropy Alloys
Authors: Yao Xiaofei , Wei Jingpeng , Li Tianye
Published: August 2019

In order to improve the mechanical properties of CoCrFeMnNi high entropy alloy, CoCrFeMnNiMox high entropy alloy were prepared by adding different content of Mo to re-alloying. The microstructure and phase composition were analyzed by OM, SEM, EDS and XRD, and the mechanical properties were tested by tensile test. The effects of Mo content on the phase composition and microstructure of CoCrFeMnNi high entropy alloy were investigated, and the mechanism of its influence on mechanical properties was studied. The results showed that with the increase of Mo element content, the crystalline morphology of CoCrFeMnNiMox high entropy alloy is change from dendrite crystals to cellular crystal, and the yield strength of the alloy is not change significantly. In the case of Mo content is less than 7%, Mo as substitutional atom is dissolves in the crystal structure of CoCrFeMnNi high entropy alloy substrate, which has function as solid solution strengthening, so that the strength of the alloy increases slightly, but the plasticity are not change significantly. In the case of Mo content is more than 7%, the ζ (CrMo) phase is precipitates in the alloy substrate, which has plays effect of second phase strengthening, so that strength of the alloy is increase significantly, and the plasticity is decreases obviously.