bluuebunny/crossref_metadata_2025 huggingface dataset:
Calculated phonon modes, infrared, and Raman spectra in ZnGeGa2N4
Authors: Ratnaparkhe Amol , Lambrecht Walter R. L.
Published: August 2020

Alloys between group III nitrides and the corresponding heterovalent II–IV-N2 compounds have recently been proposed as a further way of tuning the properties of nitride semiconductors. At 50% composition, a new ordered compound with composition ZnGeGa2N4 and space group Pmn21 was found, which has the lowest energy among wurtzite based structures. This structure obeys the local octet rule that every N is surrounded by two Ga, one Zn, and one Ge, ensuring local charge neutrality. Here, we investigate the vibrational properties of this new compound and provide predictions for its related infrared and Raman spectra, which may become useful for the characterization of this material. A group theoretical analysis, phonon frequencies and related Born effective charges, dielectric constants, infrared oscillator strengths, and Raman tensors are presented. Polarized infrared and Raman spectra for different scattering geometries are presented, as well as the phonon band structure and density of states.
Negative differential stresses in niobium: Analysis of x-ray measured pressure–volume data
Authors: Singh Anil K. , Takemura Kenichi
Published: August 2020

The macro-stresses that develop in a sample under nonhydrostatic compression in a diamond anvil cell (DAC) are axially symmetric about the load axis, the axial stress component being larger than the radial stress component. The difference between the two, termed differential stress t, is a positive quantity. The lattice strain theory (LST) suggests that the measured unit cell volume using conventional x-ray diffraction geometry of the DAC is overestimated in the presence of a positive t. In an earlier study on niobium, one set of x-ray measured compression data was found to yield negative t. It is suggested that the inward collapse of the gasket leads to negative t. It is shown that the volume-effect produced by negative t is also in accordance with the existing LST.
Lead-free antiferroelectric AgNbO3: Phase transitions and structure engineering for dielectric energy storage applications
Authors: Gao Jing , Li Qian , Zhang Shujun , Li Jing-Feng
Published: August 2020

The development of electronic materials for storing electrical energy is a thriving research field, where the materials used in batteries, supercapacitors, and dielectric capacitors have attracted extensive interest in last decades. The dielectric capacitors showing unique characteristics such as high power density and large charge/discharge rate have been actively studied, where the antiferroelectrics demonstrate great potentials for dielectric energy storage applications by storing and releasing energy upon a reversible electric-field induced antiferroelectric–ferroelectric phase transition. Recently, lead-free antiferroelectric AgNbO3 has emerged as a promising candidate to substitute conventional lead-based antiferroelectrics (such as PbZrO3) in energy storage applications. The phase transition dynamics of AgNbO3 is driven by a complex sequence of oxygen octahedron tilting orders in addition to cation displacement, which can be effectively engineered by a doping strategy. In this article, we present a succinct overview of the phase transition mechanisms in AgNbO3-based ceramics and describe how the phase transition characteristics are affected by the dopants. By exploring the composition related average structure and local structural evolutions, we provide a view toward the goal of establishing a link between the phase transition and physical properties tailored for dielectric energy storage applications.
Highly efficient nondoped bilayer organic light-emitting diodes based on triphenyl phosphine oxide protected iridium complexes
Authors: Wei Ying , Kan Wenjing , Zhang Jing , Xu Hui
Published: August 2020

Nondoped phosphorescent organic light-emitting diodes (OLEDs) with simplified stacks are desired for practical displaying and lighting applications. However, doping emissive layers are commonly adopted due to serious triplet quenching of phosphors. Here, we demonstrate high-efficiency nondoped bilayer OLEDs based on triphenylphosphine oxide protected iridium(III) complexes. The host feature of peripheral phosphine oxide groups effectively suppresses intermolecular interaction induced quenching. As consequence, the maximum external quantum efficiency beyond 20% and near-zero roll-offs at 1000 nits were achieved, comparable to the best nondoped phosphorescence devices.
Effects of fuel morphology on ember generation characteristics at the tree scale
Authors: Hudson Tyler R. , Bray Ryan B. , Blunck David L. , Page Wesley , Butler Bret
Published: August 2020

This work reports characteristics of embers generated by torching trees and seeks to identify the important physical and biological factors involved. The size of embers, number flux and propensity to ignite spot fires (i.e. number flux of ‘hot’ embers) are reported for several tree species under different combinations of number (one, three or five) and moisture content (11–193%). Douglas-fir (Pseudotsuga menziesii), grand fir (Abies grandis), western juniper (Juniperus occidentalis) and ponderosa pine (Pinus ponderosa) trees were evaluated. Embers were collected on an array of fire-resistant fabric panels and trays filled with water. Douglas-fir trees generated the highest average ember flux per kilogram of mass loss during torching, whereas grand fir trees generated the highest ‘hot’ ember flux per kilogram of mass loss. Western juniper produced the largest fraction of ‘hot’ embers, with ~30% of the embers generated being hot enough to leave char marks. In contrast, only 6% of the embers generated by ponderosa pine were hot enough to leave char marks. Results from this study can be used to help understand the propensity of different species of tree to produce embers and the portion of embers that may be hot enough to start a spot fire.
Phosphorylated CtIP bridges DNA to promote annealing of broken ends
Authors: Öz Robin , Howard Sean M. , Sharma Rajhans , Törnkvist Hanna , Ceppi Ilaria , KK Sriram , Kristiansson Erik , Cejka Petr , Westerlund Fredrik
Published: August 2020

Significance

The DNA of our cells is constantly exposed to various types of damaging agents. One of the most critical types of damage is when both strands of the DNA break, and thus such breaks need to be efficiently repaired. It is known that CtIP promotes nucleases in DNA break repair. Here we show that CtIP can also hold the two DNA strands together in solution when DNA is free to move, using novel methodology that allows the monitoring of thousands of single DNA molecules in nanofabricated devices. DNA bridging likely facilitates the enzymatic repair steps and identifies novel CtIP functions that are crucial for repairing broken DNA.
Enhancer dependence of cell-type–specific gene expression increases with developmental age
Authors: Cai Wenqing , Huang Jialiang , Zhu Qian , Li Bin E. , Seruggia Davide , Zhou Pingzhu , Nguyen Minh , Fujiwara Yuko , Xie Huafeng , Yang Zhenggang , Hong Danni , Ren Pengfei , Xu Jian , Pu William T. , Yuan Guo-Cheng , Orkin Stuart H.
Published: August 2020

Significance

Gene regulatory logic reflects the occupancy of
cis
elements by transcription factors and the configuration of promoters and enhancers. As the majority of genome-wide analyses have focused on adult cells, scant attention has been paid to embryonic cells, other than embryonic stem cells. Focusing on genome-wide comparative analyses of two stages of erythroblasts, we discovered that regulation of embryonic-specific genes is promoter-centric through Gata1, whereas adult-specific control is combinatorial enhancer-driven and requires Myb, which is confirmed by increased enhancer–promoter interactions of adult specific genes. Extending genome-wide comparative analyses more broadly to available datasets of diverse mouse and human cells and tissues, we conclude that the progressively increased enhancer dependence of cell-type–specific genes with developmental age is conserved during development.
Make us difficult
Authors: Mehl Seth
Published: August 2020

This paper introduces a previously undiscussed English construction, termed themake us difficultconstruction. Examples of the construction are presented, from theInternational Corpus of Englishand theCorpus of Global Web-Based English, and a quantitative analysis is conducted of the construction’s text frequency and variant rates. Quantitative data on specific usage patterns is employed to inform an analysis of the construction and its productivity, and recommendations are made for future research.
Effects of land-use and climate change on sediment and nutrient retention in Guizhou, China
Authors: Han Huiqing , Yang Jianqiang , Ma Geng , Liu Yue , Zhang Linan , Chen Siying , Ma Shuliang
Published: August 2020

Introduction

 Sediment and nutrient retention have significant impacts on agricultural productivity and water quality. Obvious changes of climate and land-use have deeply affected freshwater ecosystem services in the last several decades. Nevertheless, it is unclear what the differences are in the impact of climate and land-use changes on freshwater ecosystem services.

Outcomes

 The impacts of climate and land-use change on sediment and nutrient retention (two essential freshwater ecosystem services) were evaluated with the help of the Integrated Valuation of Environmental Services and Tradeoffs (InVEST) model. The results from the study area suggest a decreasing trend in sediment and nutrient retention from 1995 to 2015 when climate and land-use were changed simultaneously. A decreasing trend in sediment retention and an increasing trend in nutrient retention were presented under scenario A (climate change from 1995 to 2015 with land-use unchanged), while the sediment exported and nutrient retention exhibited a decreasing trend except sediment retained under scenario B (land-use change from 1995 to 2015 with unchanged climate). Rainfall erosivity and soil erodibility were more sensitive to the output of sediment retention, while retention efficiency produced more of an effect on nutrient retention.

Discussion and Conclusion

Climate change played a dominant role in the change in sediment retention, while land-use change had a more significant effect on nutrient retention change than climate change. The results of this study provide explicitinformation for land-use managers to reduce the negative effects associated with sediment and nutrient retention.
Early type I IFN blockade improves the efficacy of viral vaccines
Authors: Palacio Nicole , Dangi Tanushree , Chung Young Rock , Wang Yidan , Loredo-Varela Juan Luis , Zhang Zhongyao , Penaloza-MacMaster Pablo
Published: August 2020

Type I interferons (IFN-I) are a major antiviral defense and are critical for the activation of the adaptive immune system. However, early viral clearance by IFN-I could limit antigen availability, which could in turn impinge upon the priming of the adaptive immune system. In this study, we hypothesized that transient IFN-I blockade could increase antigen presentation after acute viral infection. To test this hypothesis, we infected mice with viruses coadministered with a single dose of IFN-I receptor–blocking antibody to induce a short-term blockade of the IFN-I pathway. This resulted in a transient “spike” in antigen levels, followed by rapid antigen clearance. Interestingly, short-term IFN-I blockade after coronavirus, flavivirus, rhabdovirus, or arenavirus infection induced a long-lasting enhancement of immunological memory that conferred improved protection upon subsequent reinfections. Short-term IFN-I blockade also improved the efficacy of viral vaccines. These findings demonstrate a novel mechanism by which IFN-I regulate immunological memory and provide insights for rational vaccine design.
Compact coplanar waveguide fed wideband directional antenna for medical diagnosis
Authors: Rokunuzzaman Md , Ahmed Asif , Baum Thomas , Rowe Wayne S T
Published: August 2020

This paper presents a compact coplanar waveguide fed antenna for medical diagnosis of the human head. Early diagnosis of the sophisticated organs inside the human body is possible through microwave medical imaging, which has recently achieved its popularity due to its numerous advantages. The crucial functional element for microwave medical imaging is the antenna. The antenna presented in this paper is conceived and evaluated in contact with an inhomogeneous human head tissue medium, increasing the signal penetration by removing the antenna–air–tissue transition loss. A combination of a meandered line and circular slot are utilized to achieve wideband performance at a subwavelength size. A rectangular cavity is introduced at the back of the antenna to attain directional radiation towards the inhomogeneous human head phantom. The antenna achieves increased bandwidth covering the lower microwave frequency region for medical diagnosis of a human head while minimizing ill-directed radiated fields which interfere with imaging computations. The salient characteristics of compact size, high near-field directionality, lower microwave operating frequency range and low impact on the skin surface make the proposed antenna a suitable candidate for microwave imaging of the human head.
Formation and stability of conformal spirals in confined 2D crystals
Authors: Silva Fillipe C O , Menezes Raí M , Cabral Leonardo R E , de Souza Silva Clécio C
Published: August 2020

We investigate the ground-state and dynamical properties of nonuniform two-dimensional (2D) clusters of long-range interacting particles. We demonstrate that, when the confining external potential is designed to produce an approximate 1/r
2 density profile, the particles crystallize into highly ordered structures featuring spiral crystalline lines. Despite the strong inhomogeneity of the observed configurations, most of them are characterized by small density of topological defects, typical of conformal crystals, and the net topological charge induced by the simply-connected geometry of the system is concentrated near the cluster center. These crystals are shown to be robust with respect to thermal fluctuations up to a certain threshold temperature, above which the net charge is progressively redistributed from the center to the rest of the system and the topological order is lost. The crystals are also resilient to the shear stress produced by a small nonuniform azimuthal force field, rotating as a rigid body (RB). For larger forces, topological defects proliferate and the RB rotation gives place to plastic flow.
A friction-coupled measurement model of a 3D scanning probe with unequal stiffness
Authors: Zheng Weikang , Liu Zhigang , Guo Junkang
Published: August 2020

The friction force during the scanning of a three-dimensional (3D) probe inevitably leads to undesired tangential displacement, the processing of which is challenging, especially for probes with unequal stiffness. In this paper, a new friction-coupled measurement model of the probe is deduced based on the principle of mechanics so as to realize the positioning and tracking of any friction force between the stylus ball and the sample surface. Considering the two features of the time-varying normal displacement in the scanning and the 3D unequal stiffness of the probe, this paper reveals the nonlinear bidirectional conversion between the 3D resultant force and the resultant displacement at the measuring end. The measurement deviations and the geometric relationship among the frictional force, equivalent force, normal contact force and friction-coupled force are theoretically analyzed. In addition, the finite element analysis (FEA) and calibration experiment analyze the force characteristics and sensitivity of the probe, and obtain the friction-coupled measurement model for actual measurement. The designed measurement experiment on the scanning trajectory compares the calculation difference of the displacement and azimuth angles with and without friction, and obtains a conclusion consistent with the theory and simulation.
Sparse feature extraction based on periodical convolutional sparse representation for fault detection of rotating machinery
Authors: Ding Chuancang , Zhao Ming , Lin Jing
Published: August 2020

Sparse fault transient extraction is the primary step in rotating machine fault detection. In the present paper, periodical convolutional sparse representation (PCSR) is proposed for reliable separation of fault transients imbedded in raw vibration signals. Specifically, a sparse optimization problem of PCSR is constructed, in which periodical fault transients and harmonic components are sparsely represented by a learned dictionary and Fourier dictionary, and the periodicity and group sparsity of sparse coefficients related to sparse fault transients are also incorporated. Meanwhile, to further promote the sparsity of the sparse coefficients, a non-convex function is also introduced into the optimization problem. In addition, an iterative algorithm is developed to resolve the constructed sparse optimization problem, and the parameter selection method is also investigated to ensure the fault transient extraction ability of PCSR. The performance of the proposed PCSR is assessed via a synthetic and actual vibration signal. The results illustrate that the proposed PCSR has an excellent ability in fault transient extraction and machine fault detection.
Relative stopping power measurements and prosthesis artifacts reduction in proton CT
Authors: Civinini Carlo , Scaringella Monica , Brianzi Mirko , Intravaia Matteo , Randazzo Nunzio , Sipala Valeria , Rovituso Marta , Tommasino Francesco , Schwarz Marco , Bruzzi Mara
Published: August 2020

We present a set-up for proton computed tomography (pCT), composed of a microstrip silicon tracker and a YAG:Ce calorimeter, able to directly measure the relative stopping power (RSP) maps to be used in hadron therapy. The system, tested with an electron density phantom at the Trento proton Therapy Center, is able to correlate measured and expected RSP with discrepancies of the order of 1% or less. Furthermore, pCT tomographies of an anthropomorphous head phantom taken with our device, when compared with x-ray CT images of the same object, evidence a significant reduction of artifacts induced by titanium spinal bone prosthesis and tungsten dental filling.
Alpha particle ripple loss in CFETR steady-state scenario
Authors: Zhao Rui , Wang Zheng-Xiong , Wang Feng , Hao Bao-Long , Team CFETR
Published: August 2020

Confinement of alpha particles is one of the key issues of burning plasma in tokamaks. Due to the discreteness of the toroidal field (TF) coils, the loss alpha particles induced by TF ripple can cause a strong heat load on the first wall. In this work, by using the guiding center code ORBIT, we investigated alpha particle TF ripple loss in Chinese Fusion Engineering Test Reactor (CFETR) steady-state scenario (v20190422), in which both the initial distribution and classical steady-state slowing down distribution of alpha particles are considered. Effects of TF ripple on three particle loss mechanisms, namely prompt loss, ripple well trapping loss and stochastic diffusion loss, are analyzed in detail. Through comparison, it is found that the stochastic diffusion is the main mechanism of alpha particle ripple loss. Moreover, the toroidal and poloidal profiles of the heat load on the first wall are calculated and compared with the safety threshold of CFETR. In addition, a comparison study of alpha particle ripple loss in the hybrid scenario (v20190422) has been carried out. It is found that both total particle loss fraction and maximum heat load in the steady-state scenario are approximately 50% larger than those in the hybrid scenario.
Alternative design strategy and multi-material integration in the development of biologically-inspired soft robots: a proof-of-concept
Authors: Romanò Jacopo , Lazzari Fabio , Garavaglia Lorenzo , Pittaccio Simone
Published: August 2020

This study investigates the feasibility and consequences of using complex, nonlinear geometries in the manufacturing of soft robots actuated with shape memory alloys (SMAs). Anatomically-informed shaping of the functional elements was exploited to design the components of a finger-like soft robot. The SMAs were characterised and selected to provide the device actuation. This process involved thermo-mechanical tests to obtain material parameters for a finite element method model, which was then used to carry out a comparative analysis of different actuator shapes. Additive manufacturing and multi-material integration were then exploited to manufacture the device. The soft robot actuation was characterised using a combined thermal and motion-capture-based analysis. The paper presents a shape-mediated design strategy to obtain soft actuation in an integrated multi-material through the introduction of conjugated nonlinear shapes for the constituents and a spatially-changing relationship between their sections/stiffnesses.
A new invertible model of magnetorheological damper based on sigmoid function
Authors: Lu Hongwei , Xu Zhongming , Gao Kaizhan , Zhang Zhifei , Li Zhi , Xie Jujiang
Published: August 2020

As an intelligent device, the magnetorheological (MR) damper has received extensive attention in many fields. However, in the real-time control system, it is still extremely necessary to develop a simple, accurate and invertible dynamic model of the MR damper. In this work, a new invertible MR dynamic model based on sigmoid function is proposed. According to the experimental data of a common MR damper, it is assumed that the damping force at zero velocity under constant current is only related to current and independent of the excitation frequency. The preliminary sigmoid model based on this hypothesis can better adapt to different frequency excitations while reducing the complexity of the model. In addition, according to the parameter analysis of the proposed preliminary model, the relationship between the parameters and the input current is reasonably simplified, so that the final model can meet reversibility requirements in the control system while ensuring accuracy. In order to evaluate the performance of the proposed model, it is compared with the existing sigmoid models from the literature. The results show that the proposed model has certain advantages in the number of parameters, accuracy and reversibility, which is suitable for the real-time control system.
Application Research on Quality Stability Control of a Spray Drying Tower for Naphthalene Superplasticizer based on Siemens PLC
Authors: Xie Yonghui , Liu Ruchun , Wang Xiaojun , Hou Xujie , Shi Qinghai
Published: August 2020

This article introduced a control scheme based on Siemens PLC to handle the quality stability issue in operation of the spray drying tower for Naphthalene Superplasticizer. A series feed-forward control scheme is proposed to solve the problems of water content fluctuation of naphthalene series water reducer slurry and solid content fluctuation caused by frequent and wide range fluctuation of gas pressure as fuel. The practical application shows that the control scheme can handle the fluctuation of water content well.
Distribution Model of Time Between Failures in CNC System
Authors: Lu Guiyou
Published: August 2020

In this paper, the fault data of 50 CNC milling machine CNC systems are used. By observing the scatter plot of the probability density function and distribution function of the time between faults, the type of the distribution model is initially selected. After the inspection, the distribution model of CNC system failure interval time was established, and the three main reliability indexes were evaluated.
Identification of Isomorphism in Multistage Planetary Gear Trains
Authors: Wang Jungang , Yang Shinan , Liu Yande , Mo Ruina , Zeng Liping
Published: August 2020

Isomorphism identification of kinematic chains occupies an important place in the field of mechanism structure synthesis. A method to identify the isomorphism of multistage planetary gear trains is proposed in this paper. Firstly, the structure topology model and the corresponding link-link adjacency matrix are presented, to describe the schematic diagram of multistage planetary gear trains. Then, based on the hamming number method, the hamming number matrix is obtained by the link-link adjacency matrix, and the hamming value of link, the hamming number and the hamming strings of multistage planetary gear trains are introduced, which can determine whether the multistage planetary gear trains is isomorphic or not. The study shows that this work is beneficial to the development of new multistage planetary gear trains.
Feeder Layout Optimization and Feeding Sequence Optimization in High Speed and High Precision Placement Machine
Authors: Huang Yinhua , Zhao Lianxing , Liu Peng
Published: August 2020

As for the multi-optimization mutual coupling process optimization for mounting production with multiple 1210 or1812 resistor components and the relatively low nozzle requirement, a fast multi-objective hierarchical optimization method with low matching requirement for parallel nozzle and placement sequence optimization is proposed. In the hierarchical structure, the nozzle optimization is constructed as a 0-1 integer programming optimization model for the first master hierarchy. In the second hierarchical, feeder optimization and picking order are parallel optimized based on the first hierarchy optimization. The respective problems related algorithm strategies have been proposed. The engineering experiments show that this Feeder layout optimization and Feeding sequence optimization method can significantly improve the overall performance of the multi-head placement machine with high speed and high precision.
Research on 3D virtual display method of American style modern home furnishing
Authors: Wu Juan , Feng XiYe
Published: August 2020

The theme of this paper is to design a 109 square meter three bedroom and two hall house with plane plan and 3D display of soft decoration. The purpose of this paper is to create a comfortable American style modern home environment for the householder. The key content of the home design is the design of the plan: including the removal of the wall, the plane layout, the ceiling size, the ground pavement, the lighting circuit and the erection Face; soft decoration: including sofa, dining table, chair, bed, cabinet, adornment and other material appearance and color matching.
Extension Intelligence for Process Manufacturing
Authors: Li Xingsen , Guo Hengfa , Chen Siyuan
Published: August 2020

Artificial Intelligence (AI) is supporting much innovation in intelligent manufacturing in the ubiquitous network information environment, while there are still many problems such as production quality vs costs to produce, and new intelligent theory and method is needed. Based on Extenics, we put forward the concept of Extension Intelligence and analyse the characteristics of extension intelligence, then present its implementation path and steps for the application. Multi-dimensional information and knowledge will be extended from the industrial big data of manufacturing system and the Internet to build the basic-element model in order to deal with engineering problems by extension and transformation algorithms. The application proves the validity of Extension Intelligence.
Research on Framework of Fault Prognostics and Health Management System for Complex System
Authors: Junbin Shi , Huanxi Cai , Xianming Jiang
Published: August 2020

This paper studies the framework of fault prognostics and health management for complex systems. Aiming at the problems of lack of effective organization and management of fault diagnosis resources and low resource sharing rate, this paper analyzes the characteristics of complex system and the shortcomings of traditional diagnosis mode, puts forward the service-oriented PHM system architecture, studies the system service mode and characteristics, analyzes the key technologies and main function modules of establishing the system, and carries out public PHM system service level for complex equipment field Taiwan research provides a new way of thinking.
Study on the metal flow behaviour of deformation areas of large ring radial-axial rolling process
Authors: Cheng S X , Gu R J , Du X B , Shao G D , Yang D X , Yang B
Published: August 2020

Ring radial-axial rolling technology is the best method to produce high quality large seamless ring. The metal flow behaviour of deformation areas of large ring radial-axial rolling process is studied. It is found that the fishtail pit of up-down surface of the ring section arises after the section passes through radial rolling area and that of in-out surface of the ring section arises after the section passes through axial rolling area. In order to gain better ring section, single radial rolling process is needed to remove the fishtail pit of in-out surface after double radial-axial rolling process. The study is very useful to constitute the process scheme of large ring radial-axial rolling.
Selection and strength check on fasteners of protective structure in cryogenic wind tunnel
Authors: Yuan-jia Song , Huan Lai , Wan-hua Chen , Wei Zhang , Yu Hou
Published: August 2020

Protective structure, acted as a substructure of internal insulation system in cryogenic wind tunnel, is in possession of such advantages of isolating insulation unit from cryogenic medium and reducing cold energy loss. However, the protective structure is continuously subjected to alternating pressure during the operation of cryogenic wind tunnel. Thus, the type selection and strength check on connecting fastener, acted as weak bearing component in protective structure, are investigated. Firstly, according to the composition of protective structure, three key connecting positions are determined and the corresponding connecting fasteners are selected. Then, according to the cryogenic wind tunnel working condition, the theoretical mechanical models of connecting fasteners are built under different working conditions. Finally, involving the force and moment balance, mechanics analysis and strength check are conducted on connecting fasteners. The obtained results show that the selected fasteners are conformed to the strength requirement of cryogenic wind tunnel in service, which paves the way for building the cryogenic wind tunnel in the future.
Research on SOC estimation of battery based on BP neural network
Authors: Liu Qian , Shen Yan-Jin
Published: August 2020

State of charge (SOC) estimation is the core function of the battery management system of new energy vehicles. In this paper, BP neural network algorithm is used to estimate the real-time SOC value of the battery according to the working voltage, current, temperature, internal resistance and SOC of the previous moment. In order to improve the estimation accuracy, the initial weights and thresholds of BP neural network are optimized by genetic algorithm. The test results show that the estimation error of the optimized neural network is significantly reduced.
Approximate Stiffness Element Method for Complex Section Beam Modeling
Authors: Huang Xinshen , Li Hao , Zhang Zhenkun , Zheng Jianguo , Pei Hailong
Published: August 2020

In this paper, a finite element method of simulating complex section beam element with approximate stiffness element is presented. By establishing an approximate stiffness element, the basic mechanical properties of the element are equivalent to the original complex section beam element’s. The approximate stiffness element has several sub-section beam elements, which intersect with other beam elements in space. The problem that missing of intersection points among complex section beam and other beams, which is caused by using conventional beam element, is solved. The error between the approximate stiffness element and the original complex section beam element is analyzed by theoretical deduction, and the feasibility and accuracy of the approximate stiffness element method are verified by the physical test of a bus body.
Sealing Analysis of Joint Surface of Transmission Case of An Electric Vehicle
Authors: Long Y , Wang H X , Sun Z D
Published: August 2020

In view of the oil leakage failure of the joint surface of the transmission case of an electric vehicle, a contact non-linear finite element method was used to analyze the tightness of the joint surface of the transmission case of an electric vehicle. Based on the workbench software, a finite element model of the transmission case is established. Determining the sealing performance of the case by calculating the distribution of the surface pressure and the opening of the case under static and high-speed conditions. Two optimization methods are proposed. The first method is to widen the box contact area of the oil leakage area; the second method is to increase the tightening bolts in the oil seepage area. After comparing the data obtained by the two optimization methods with the original data, it shows that reducing the sealing bolt spacing and widening the sealing surface where the sealing performance is poor makes the sealing performance greatly improved. This method provides an effective way to determine the tightness of the transmission case, provides a basis for optimal design, and lays the foundation for experimental research.
Dynamic Performance and Fatigue Analysis of ASP Pump Rotor
Authors: Qichen Niu , Gongxue Zhang , Yanhui Meng , Sen Yang , Yinfeng Tuo , Zhi Ma
Published: August 2020

In this paper, static analysis, modal analysis and harmonic response analysis are carried out on the rotor structure of single-stage double-suction centrifugal pump. The fatigue life of the rotating shaft was analyzed with the nCode Designlife module in ANSYS. The results show that the maximum equivalent stress is greater than the allowable stress of the material and is located at the journal of the transmission torque connected with the coupling. The maximum deformation also occurs here at 0.4857mm. The axis of rotation is liable to resonate at the first natural frequency of the non-rigid body. The frequency which has the greatest influence on the vibration of the rotating shaft is near the third and fourth order natural frequencies of modal analysis and should be avoided. The minimum number of circulation at the maximum stress is 1.785e7 times, and other positions are above 1014 times. The results show that the pump group works stably under the design condition and the rotor performance meets the design requirements.
Error Prediction of CMM Using a Hybrid Model Based on Neural Network Quantile Regression and Kernel Density Estimation
Authors: Wu Haiting , Zhang Mei , Li Guihua , Zhao Haifeng , Wu Xiaoping
Published: August 2020

The sources of dynamic measurement error of CMM are complex and influence each other and the traditional parameter modeling method is very difficult to model. In this paper, we propose a hybrid model which combines neural network quantile regression and kernel density estimation. The hybrid model realizes the advantages of multi-angle analysis, nonlinear fitting data and non-parametric error prediction. We use this model to analyze the complex relationship between dynamic measurement error value and 3d coordinates, positioning velocity, proximity distance and contact velocity. The results show that our model has good predictive performance and is superior to the least squares estimation model.
Measurement of mechanical properties of carp scales based on digital image correlation method
Authors: Fu Zhongnan , Ma Wanlong , Zhu Tiantian , Ye Pei , Li Guihua
Published: August 2020

As a kind of high quality natural material, the structure and mechanical properties of fish scale have been widely concerned. At present, there are few researches on fish scales in China, and most of them focus on the composition and nutritional value of fish scales, while there are few researches on their mechanical properties and microstructure. In this paper, based on the digital image correlation method and a set of self-built strain measurement system, the tensile strain of fish scale specimens was measured, and the fish scale specimens after surface speckle treatment were tensile tested and data were collected. The mechanical properties of fish scales in the uniaxial drawing process were studied and analyzed, and the microscopic images showed that the tensile strength of fish scales was related to the number of collagen fiber layers in their inner layers.
A research on evaluation and development of single-pedal function for electric vehicle based on PID
Authors: Yongqiang Zhao , Xin Zhang , Jiashi Li , Haitao Huo , Teng Ma , Chunyu Zhou
Published: August 2020

The pure electric vehicle can be driven and regenerative braked by motor, so the development of single-pedal function which is realised by motor torque and evaluation on drivability of electric vehicle is researched in this paper. Driver can launch, accelerate, brake even park only by operating accelerator pedal. Single-pedal function is researched based on PID and Co-simulation using Matlab/Simulink and Carsim. Evaluation standards and indexes about drivability of electric vehicle with sing-pedal are developed which is implemented on a real vehicle. The research can support the optimization and development of single-pedal function for electric vehicle.
Study on the forward slip of cup with variable wall thickness during roll forming
Authors: Zhang Baohong , Hu Bin , Zhang Zhimin , Zhao Xi
Published: August 2020

Based on the principle of plastic forming, the metal flow of cup with variable wall thickness during roll forming is analyzed, and the formula of its coefficient of forward slip is derived. By comparing with the numerical simulation results, the correction formula of the coefficient of forward slip at the rim of roller is obtained. The correction formula is verified by experiment. The results show that the error between the theoretical and experimental value is 4.5%, and the agreement between them is good. This research provides a basis for the design of the roller groove for the roll forming of cup with variable wall thickness.
Electromagnetic and FEM analysis of a novel electric driving knitting needle of moving coil stack PMLM schema
Authors: Liangzhi Fan , Xiangyang Zhou , Shilin Wu
Published: August 2020

A novel electric driving knitting needle of moving coil PMLM schema is put forward in this paper. Magnet elements are arranged in a matrix form and 3-phase coil windings are epoxy packaged as the knitting needles that reciprocating along the air gaps inside the magnet matrix. Both the static magnetic flux density in air gaps and the unbalanced magnetic force on each magnet element are put forward in analytical formula. 2D and 3D FEM analysis have been carried out both in static magnetic field analysis and transient electromagnetic field analysis. It’s verified that both the structure rigidity and the motion performance are safe, and the performance of approximately 7 N peak hauling force and 20 mm movement at 20 Hz are able to be fulfilled. Future research will be reported and focused on the prototyping and the driving circuit & control strategy.
Solidification forming and numerical simulation of 90° wear-resistant bend with high-vanadium cast iron
Authors: Chen P H , Zhang Y , Li R Q
Published: August 2020

Casting defects and macro-segregation had greatly affected the product quality. This paper revealed the effects of the arrangement of the gating system and superheat of molten iron on solid fracture, shrinkage porosity, cooling cracks, and effective stress-strain by simulation with the commercial software Pro-cast. Optimized parameters were used to produce a batch of 90° bends. The microstructure of an as-cast bend was characterized by scanning electron microscopy, and the service life of the bend was evaluated with delivery capacity. Simulation results showed that a 30° arranged location on the outer bend and superheat of 60 K comprised the optimized parameters. A batch of bends were produced with the optimized casting system and superheat, and in contrast to the simulation results. The simulation results were in accordance with the experimental results. In addition, the delivery capacity of high-vanadium cast iron, which was heat-treated using Quenching-partitioning process, was 26000 m3 and the economic costs were effectively reduced.
Numerical Analysis of Multi-pass Cold Spinning of Superalloy of Cylindrical Part
Authors: Li Z X , Shu X D , Ye B H
Published: August 2020

In view of the poor plasticity and easy cracking of superalloy at room temperature, the multi-pass cold spinning of cylindrical part was studied. Firstly, the tensile test of superalloy GH3030 is carried out, and the true stress-strain curve is obtained. Then, the numerical models of 250 and 87.5 diameter-thickness ratio blank are established, and the stress and strain field, wall thickness distribution and tool force distribution of the cylindrical part are analyzed and compared. The wrinkle model of 250 diameter-thickness ratio blank was analyzed, and the experiment of 87.5 diameter-thickness ratio blank was carried out. The results show that the wall thickness of the cylindrical part has metal accumulation at the flange, and the thickness of the waist is very small, which is easy to crack under the repeated forming of the roller; the wall thickness distribution of the large diameter-thickness cylindrical part is more uniform, but it has a great challenge to the equipment force and the equipment stiffness. The main reason for the flange wrinkle is staggered distribution of the tangential tensile and compressive stress of the whole flange.
Study on the Mechanical Properties of 125S Casing for oil and gas wells
Authors: Qi Lou , Wei Du , Xinli Han , Wenhong Liu , Huan Song
Published: August 2020

In the process of evaluating the quality of a batch of 125S casing for oil and gas wells, it was found that the mechanical properties of different casing bodies in the same batch were significantly different, and the fluctuation range of yield strength was up to 60 MPa. The steel pipe with the lowest yield strength was not satisfied according to the technical standards. In order to study the causes of the uneven tensile properties, the chemical composition analysis, tensile tests, Charpy impact tests, Rockwell hardness tests and metallographic analysis were investigated for the two casings of this batch. Through the analysis of the test results, it is found that the chemical composition and metallographic structure of this batch of casing were conforming to with the design requirements, and the materials possessed high toughness. The problem of non-uniform performance of this batch casing was generated from the heat treatment stage during the production process. The excessive tempering temperature caused the reduction of material strength.
Investigation on the adhesion improvement of organic coatings on the surface of hot-dip galvanized steel
Authors: Zhu L Z , Liang Y J , Yang J H , Chen X
Published: August 2020

In order to solve the problem of poor adhesion of organic coatings on the surface of hot-dip galvanizing, we conducted a series of experiments to select the suitable pre-treatment method and type of the coatings. We adopted temperature shock & alternating damp heat combined test and waterproof test to simulate the service conditions, and investigated the adhesion of organic coating on the surface of hot-dip galvanizing in the wet environment. With the XPS analysis, we discussed the avoidance of formation of weak boundary layer on the hot-dip galvanizing surface by pre-treatment, and the improvement on adhesion of the organic coatings. We also proposed the pre-treatment method of coupling treatment with silane or combined alkali washing & grinding procedures, by which the organic coating on the hot-dip galvanizing surface performed excellent adhesion and water proof ability against wet conditions.
Study of surface metallization on the electromagnetic shielding performance of carbon fiber reinforced composite
Authors: Wu L Q , Chen X , Zhu L Z
Published: August 2020

In order to improve the electromagnetic shielding performance of CFRP structures, a series of CFRP samples were surface metallized with combined chemical then electrochemical plating, coating conducting paints and metal spraying of aluminium, respectively. The shielding performances with different surface metallization methods were compared, and the investigation of thickness of metallization layer and the composites was carried out, which showed that the increase in thickness of metallization layers and the composites contributed to the increase of shielding performance. As a result, we have found a superior improvement on shielding performance with surface metalized in nickel plating comparing with metal spraying, which could substitute the commonly used method of metal spraying with aluminium.
The failure mechanism of a selective laser melting Nickel-based superalloy at high-temperature
Authors: Guo Xiaojun , Ling Huixiang , Huang Xiaozhong
Published: August 2020

Selective laser melting (SLM) processed Inconel 625 exhibits outstanding mechanical properties, compared with the conventionally manufactured counterparts, and has been widely used in aeronautic and aerospace engineering. In this study, the fracture mechanism of SLM-processed Inconel 625 in different building directions was systematically characterized and analyzed using scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The results reveal that the HIP treatments have a significant influence on the deformation and rupture behavior of the SLM-processed Inconel 625.
Study on antifreeze Properties and pore structure of Basalt Fiber Reinforced Concrete
Authors: Jun LIU , Shuo ZHAO , Runqing LIU
Published: August 2020

We designed basalt fiber concrete with a volume content of 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%. Through the mass loss rate and dynamic modulus loss rate after different freezing-thawing cycles, the antifreeze performance of concrete was tested. As the internal capillary pores of concrete are the main channel for corrosive medium and other harmful substances to invade the internal concrete, the durability of concrete is closely related to the internal pore structure. The microstructure and pore structure of basalt fiber concrete were tested by sem and Mercury Injection Apparatus, so as to analyze the microstructure of the interface between fiber and cement and discuss the strengthening mechanism of basalt fiber concrete. The results indicate that the basalt fiber can improve the freeze-thaw cycle of concrete With the increase of the content of basalt fiber, the gel has greater adhesion and binding force to basalt fiber, and the hydration products attached to the surface of basalt fiber gradually decrease When the content of basalt fiber is 0.3%, the frost resistance of concrete is the best. The addition of basalt fiber optimizes the hole structure and reduces the internal defects of concrete, thus improving the durability.
Effect of aircraft deicer on deicer-scaling resistance and frost resistance of airport pavement concrete
Authors: Lai Y , Liu Y , Wang P , Ma D X , Guo B , Sun K , Hou S
Published: August 2020

This paper studies the effect of aircraft deicer on deicer-scaling resistance and frost resistance of airport pavement concrete. The mass loss and surface profile of non-air-entrained and air-entrained concrete eroded by water and aircraft deicer are analysed. The surface profile, mass loss rate and relative dynamic elasticity modulus of air-entrained concrete eroded by water and 5% aircraft deicer are discussed during freeze-thaw cycles. It is shown that the low and medium concentration deicer has a negative effect on the deicer-scaling resistance of concrete, and 5% aircraft deicer has the greatest influence. Adding air-entraining agent can improve the deicer-scaling resistance of concrete. Compared with water, 5% aircraft deicer has a negative effect on the frost resistance of air-entrained concrete. The deicer-scaling resistance and frost resistance of air-entrained concrete meet requirements for airport pavement in the most severely cold regions in China.