bluuebunny/crossref_metadata_2025 huggingface dataset:
Software Reliability Index Determination Based On Mission Profile
Authors: Ding J Y , He W , Xue J K , Shen X M , Han X Y
Published: February 2021

The reliability parameter selection scheme and reliability index determination method of embedded software are always the focus and difficulty of research. Based on the analysis of the existing technology and the actual situation of the software, this paper proposes a method to determine the software reliability index based on the task profile. This method firstly analyzes and selects the software reliability parameters combined with the characteristics of embedded software, then generates the task sequence according to the task characteristics and failure characteristics of embedded software and establishes the task profile. Finally, the parameters are selected according to the reliability parameter selection principle and the reliability index is determined according to the software characteristics.
Simulation Analysis of Complex Aluminium Alloy Structural Component of High-Speed Train
Authors: Qian Wenxue , Zeng Xianhai , Huang Shuanghui , Yin Xiaowei
Published: February 2021

High-speed trains are now the most important medium- and long-distance mode of transport in many countries, and green economy is one of the important directions of high-speed train design. Aluminum alloy material is widely used in various structural parts of high-speed trains due to its advantages of high strength and low density, etc. As the speed of high-speed trains is getting faster and faster, the load on the car body structure is getting bigger and bigger, the safety, reliability and longevity of aluminum alloy structure has received wide attention. In this paper, the stress distribution, maximum stress value and maximum stress point position of aluminum alloy structural members of high-speed trains are analyzed in detail based on the real load situation, and the influence of stress level on train operation is analysed. The above work has certain reference significance for the design of high-speed train.
Performance Degradation Modeling and Reliability Analysis of Aviation Connectors in Marine Environment
Authors: Wang Ge , Zhou Jian-Qi , Zhao Yong-Tao , Feng Jing , Sun Quan
Published: February 2021

The influence of marine environment on the reliability of a certain type of aviation connectors is studied. Firstly, the step-stress accelerated degradation test which simulates marine environment in South China Sea is designed. And the performance parameter data of four material types of aviation connectors: stainless steel, composite cadmium plating, titanium alloy and aluminum alloy cadmium plating are collected. And then, in order to study the degradation of performance parameters, the mixed effect model is adopted. At last, the reliability lifetime of four material types of aviation connectors are evaluated by means of reliability modeling and analysis. This research provides an effective path for reliability evaluation of aviation connectors, meanwhile it also gives a reference for aviation connectors’ selection.
Maintenance decision of meta-action unit based on Grey-BWM
Authors: Li Xinlong , Ran Yan , Yu Hui , Chen Yifan , Zhang Genbao
Published: February 2021

In order to reduce the maintenance cost, improve the availability, reliability, safety and product quality of the equipment, it is necessary to maintain the equipment. The choice of maintenance strategy is not only related to economic interests, and even endanger personal safety. Traditional maintenance decision-making often takes parts or the whole system as the decision object. Taking components or systems as decision-making objects, too large grains are easy to lead to wrong maintenance decisions, resulting in over repair or under repair; taking parts as decision-making objects, the analysis and decision-making of the system is too complicated. In this paper, the meta-action unit is taken as the research carrier, and the grey weight of each criteria is obtained by combining the grey system theory with the best worst method (BWM). The comprehensive grey value of the evaluation is calculated by the grey number algorithm and its comparison method, and the best maintenance scheme is obtained by comparison. The example analysis proves the effectiveness of the method.
Reliability Analysis of Dependent Systems using Copula Bayesian Networks: A Case Study
Authors: Xie Guofeng , Xing Liudong , Khan Faisal , He Liping
Published: February 2021

The Bayesian Network (BN) is a technique that utilizes updating, adapting and discrete-time-based analysis properties for system reliability analysis. Although the BN is a powerful technique, it still faces the challenge of modelling non-linear complex correlations of process components. This paper presents a Copula Bayesian Network (CBN) model to address challenge of modeling non-linear relationships. The superiority of the CBN model lies in integrating the advantage of Copula functions in modelling complex dependent structures with the cause-effect relationship reasoning of process variables using BN. Application of the CBN model is illustrated through a detailed reliability analysis of an example mud pump system. The results reveal the influence of different types of Copula functions and different parameters on the system reliability.
Reliability analysis of k-out-of-n Phased-Mission systems with Phase-AND requirement
Authors: Hu Y , Wang C , Xing L
Published: February 2021

In this paper, the reliability of a non-repairable phased-mission system (PMS) with k-out-of-n structure and phase-AND requirements is modeled and analyzed, where the required number of working components k and available components n may vary in different phases. The phase-AND requirement implies that the mission fails only when it fails in all the phases. In other words, the success in any one phase would lead to the successful execution of the entire mission. A new multi-valued decision diagram (MDD)-based method is suggested for reliability analysis of the considered PMS. Different from the existing methods that generate the PMS reliability model phase by phase, the proposed MDD method encompasses a fast model generation procedure that considers behaviors of all the mission phases together. The proposed MDD-based method is combinatorial and thus applicable to any types of component time-to-failure distributions. The application and advantage of the proposed method are demonstrated using an example.
Dynamic load-bearing capacity analysis for the main Transmission Mechanism of Traction Machine in a Cargo Lift
Authors: Liu Qingchao , Liu Wenzhi , Wang Zhiqi
Published: February 2021

This paper discusses the dynamic load-bearing capacity of the main transmission mechanism of worm pair traction machine in a cargo lift. By fully considering the mass, rotational inertia and friction for transmission of the worm pair, multi-body dynamics was adopted to calculate the worm gear teeth contact force and motion characteristics. Based on the nonlinear finite element algorithm for friction-contact and combined with the dynamics computation results, the finite element calculation for the teeth contact strength and bending strength were performed. The finite element calculation results and theoretical calculation results were compared to analyze their difference. The mechanism quality was evaluated from the running stability and mechanical strength, and the evaluation results show that the main transmission mechanism of traction machine in the cargo lift has good dynamic load-bearing capacity and high safety, and meets the design requirements.
Research on the Optimization Design Method of Reliability Enhancement Test of Fiber Optic Acousto-optic Modulator Based on Fuzzy Theory
Authors: Yuan Xi , Fu Guicui , Zhang Zhongqing , Wan Bo
Published: February 2021

The main purpose of the reliability enhancement test is to expose the weakness of the components in order to improve the process structure design. The current domestic test standards are Accelerated stress test procedures for electric and electronic products, Guidance on the definition and application of high-acceleration tests for avionics and so on. However, these standards have relatively broad provisions on test conditions. The feasible test schemes are not unique that lead to different required test conditions and test costs. The emerging device fiber optical acousto-optic modulator is expensive and the test cost is high. How to choose an efficient enhanced test program is particularly important. Based on the fuzzy theory, an optimization design method for the enhancement test of the fiber-optic acousto-optic modulator is established in this paper. This paper takes the test cost-efficiency ratio as the optimization target, and uses the reliability estimation deviation and cost as the fuzzy evaluation index for optimizing and designing of the enhancement test plan. Finally, the feasibility of the method is verified by case analysis.
A maintenance-replacement optimization model under a renewable hybrid warranty
Authors: Shang Lijun , Si Shubin , Cai Zhiqiang , Zhu Wenjin , Zou Anquan
Published: February 2021

In this paper, firstly, a renewable hybrid warranty policy is proposed from the manufacturer’s perspective. By integrating the replacement depending on number of failures and preventive maintenance at the expiration of the warranty, secondly, a maintenance-replacement policy is presented from the perspective of the customer. Thirdly, the consumer’s expected cost rate model is obtained and the related special models are offered. Finally, a numerical example is used to illustrate performance of the proposed maintenance-replacement policy and to analyse sensitively. As showed in the example, performance of the proposed maintenance-replacement policy is more superior.
Reliability analysis and optimization of turbocharger turbine of marine low speed diesel engine under complex load
Authors: Lin LEI , Ming-ze DING , Hong-wei HU , Yun-xiao GAO , Hai-lin XIONG , Wei WANG
Published: February 2021

In this paper, aiming at the reliability analysis and optimization of jth series marine low-speed diesel engine supercharger of Chongqing JIANGZENG Shipbuilding Heavy Industry Co., Ltd., a response surface mathematical model is constructed by using 62 groups of dispersive simulation analysis data to verify the accuracy and effectiveness of the mathematical model. Based on this, Monte Carlo sampling is carried out to obtain the reliability of turbine disk is 0.943, and the reliability of turbine blade is 0.96 Reliability optimization space. Based on NSGA-II multi-objective genetic algorithm, the reliability of turbine disk and turbine blade is optimized by taking the stress value and machining cost of turbine disk and turbine blade as the objective function. The reliability of turbine disk and turbine blade is 1, the stress value of turbine blade is optimized by 4.7941%, the stress value of turbine disk is optimized by 3.0136%, the machining cost of turbine blade is optimized by 15.5087%, and the machining cost of turbine disk is optimized by 3.9907%. Finally, the results of genetic algorithm and simulation analysis are compared, the difference is less than 5%, which shows that the data based on NSGA-II multi-objective genetic algorithm has practical application reference value.
Reliability analysis of girth welds by using finite element simulations with uncertain material properties
Authors: Qian Cheng , Meng Jin Xiao , Ren Yi , Sun Bo , Feng Qiang , Yang De Zhen , Wang Zi Li
Published: February 2021

This research proposes a reliability simulation method combining the finite element simulation technology and stress-strength model to predict the structural reliability of girth welds with the following steps. Firstly, a group of finite element simulations of the girth welds are carried out considering uncertainties of elastic moduli in the weld and core barrel materials. Then the maximum von-Mises stresses over the welds are extracted from those simulations to generate the stress distribution. Finally through a stress-strength model, the structural reliability of the girth weld is calculated by assuming its yield strength following a Normal distribution. In addition, via the proposed method, influences factors such as temperature, pressure and the uncertainty level among the elastic modulus on the weld reliability are discussed in detail.
Comparison of software defect prediction models based on machine learning
Authors: Zhang W H , He R Y , Wu L J , Jian Y , Han X Y
Published: February 2021

Software defect prediction has been widely used in software system development, among which the method based on machine learning has proved to be more effective. Firstly, the basic framework of the prediction model and the metric elements used in the prediction process are introduced in this paper. Secondly, the three main machine learning-based software defect prediction models (LR, SVM, and BPNN) are analyzed, and finally the prediction effects of the three models are compared and analyzed by using the experimental results of MDP.
Numerical simulation analysis of coal rock crushed by disc cutter based on ABAQUS
Authors: Guo Z G , Wang J , Lv S , Zhang X
Published: February 2021

In view of the lack of research on the mechanism of disc cutter cutting coal rock during the tunnelling process of coal mine rescue tunnel equipment, the ABAQUS software was used to establish the finite element model of single disc cutter crushing coal rock, and the influence of penetration and cutting speed on the rock breaking force during the process of disc cutter crushing coal rock was analyzed. The results show that the average cutting force increases linearly with the penetration and cutting speed. The maximum vertical force of the disc cutter at a penetration of 5mm is 2.6 times that at a penetration of 2mm. The impact of the disc cutter cutting force at a penetration of 3mm is obvious. The average rolling force at a cutting speed of 0.8 rad/s is twice that of a cutting speed of 0.2 rad/s. The impact of the disc cutter cutting force at a cutting speed of 0.5rad/s is obvious. Comprehensively considering the influence of penetration and cutting speed on the average value and fluctuation range of disc cutter cutting force, choosing a moderately large penetration and a large cutting speed parameter combination will help to achieve rapid and safe coal mine emergency rescue tunnelling. The method in this paper provides a basis for the optimization of the cutterhead tunnelling parameters during coal rock cutting.
Research on evaluation and inspection of pressure relief valve
Authors: guojin Zhang , yonghang Cheng , wenjing Zhao , min Ding
Published: February 2021

As a pressure relief device of pressure-bearing equipment, pressure relief valve (PRV) should be inspected once a year according to the regulations, which increasingly contradicts the long-term operation of petrochemical units. In recent years, risk-based inspection (RBI) has been widely used in inspection and maintenance of petrochemical equipment. According to the RBI results and Inspection records of PRVs in various refining enterprises, the problems encountered during the prolonging the inspection cycle of PRV are summarized, which provide reasonable basis for prolonging the inspection cycle of PRV. RBI technology is applied to 5810 PRVs in an enterprise, so that nearly 80% of the PRVs achieve the purpose of delayed inspection.In addition, suggestions for improvement meatures are provided for common problems encountered during the use and inspection of PRVs.
Knowledge-Driven Software Project Management Based on IDEAL Cycle
Authors: Jialin Tan
Published: February 2021

In recent years, aerospace products’ development has more needs for localization, integration and intellectualization, so how to improved efficiency and reliability of software development through optimizing the management modes has become the major challenge. This paper proposes a design idea of transforming the task-driven management model to a knowledge-driven management model based on the software process improvement model(IDEAL cycle). By combining the improvement process of IDEAL cycle with the knowledge-driven management activities, it achieves a knowledge-driven software project management model based on IDEAL cycle. The practice results show that, through the implementation of the program, the software team are promoted to achieve the acquisition, storage, sharing, exchange, application and innovation of knowledge while implementing software process improvement, the process capability and core competitiveness of the team are fully enhanced. The requirements of software process improvement and the knowledge-driven design are fully taken into account in program design, and its generalized workflow engine and platform function have great promotion value and applicable to other knowledge-based enterprises.
Research on Reliability Prediction method of Complex Mechanical Product Based on Meta-action Unit
Authors: Zhang Wei , Ran Yan , Li Yu-long , Zhang Gen-bao
Published: February 2021

Reliability prediction of complex mechanical product is helpful to determine the reliability state of products and that how to optimize products. Traditional reliability prediction methods of complex mechanical products come from electronic products, which need a certain amount of reliability data as support. In addition, the reliability of system complex mechanical product is generally predicted by the parts or component that make up it. However, failure of one part may not cause failure of the whole product, that will affect the accuracy of reliability prediction. To solve these problems and in order to accurately predict the reliability of complex mechanical product, a methodology based on meta-action unit (MAU) which is the basic units affecting reliability is proposed in this paper. The mechanical product is decomposed into many MAUs, and the conception of “unit quality entropy” is introduced to predict the reliability index of MAU. Subsequently, according to the reliability mathematical model of complex mechanical product and MAU, the reliability is predicted by combining interval analytical hierarchy method and eigenvector method. This paper also verifies that the method is applicable and is more accurate with a case study of the reliability of spindle box.
Multi-response optimization design based on Non- parametric error-corrected method
Authors: Tingyu GAO
Published: February 2021

The construction of a response surface model is critical to the experimental results. Traditional model construction method is parametric method. The parametric estimates may be highly biased, and the optimal control factor settings can be miscalculated if the models are not correctly specified. To solve these problems, this paper proposes a new multi-response optimization design method, Non-parametric error-corrected method. The nonparametric method provides a very useful alternative when researchers don’t have any information about the form of underlying functions. Finally, the hybrid genetic algorithm is used to achieve global optimization aiming at the expected quality loss function the validity of the method was verified by the experimental data of the femtosecond laser micro/nano-machining.
Robust parameter design of inventory policy considering the risk preference of decision makers
Authors: Yang Ying , Tang Lina , Ma Yizhong
Published: February 2021

Aiming at reducing the risk in inventory management of supply chain system suffering from the influence of uncertainties, we propose a strategy to analyse the optimal inventory policy considering different risk preference of decision makers. The proposed method is a combination of the mean-conditional value-at-risk and the response surface model. From the perspective of robust optimization, the proposed method is adopted to solve the inventory control problems in a multi-echelon supply chain system, the effectiveness of the proposed method is verified in the simulation model. Furthermore, the comparison analysis between the proposed method and the dual-response surface method is conducted in this paper, and the comparison results shows the superiority of the proposed method in improving the robustness of supply chain system.
Research on aircraft taxiing path optimization based on digraph model and Dijkstra algorithm
Authors: li Lu , jiawei Gao
Published: February 2021

in this paper, the ground structure diagram of an Airport is taken as an example, the specific flight information is substituted, and then the directed graph model is established, and various factors are transformed into weight offspring into the directed graph, and a multi factor constrained aircraft taxiing path optimization scheme is obtained. Through the specific analysis of the influence of each factor on the selection of aircraft taxiing path and the optimization scheme of taxiing path with the corresponding weight of various factors, the Dijkstra algorithm is used to calculate the specific case, and the specific optimal path of aircraft ground taxiing is obtained. The results show that the directed graph model and the optimal path of aircraft taxiing are reasonable, which can provide some reference for the controller’s command.
A Reliability Calculation Method of Safety Device in Cars
Authors: Han Z , Li Y , Tang G C , Gou H P , Xing J Q , Jiang C X
Published: February 2021

Aiming at the safety accident of children mislocked in the car incurred the death, a reliability calculation method of vehicle safety device is proposed. In order to avoid the accident as far as possible, a device is used for the monitoring and alerting of living beings in the vehicle. So the device reliability becomes particularly important. In the study, the safety logic relationship of the device unit is clarified through the detailed analysis of the composition function and work flow of the device. Furthermore, this paper introduces the method of building the device reliability models, gives the equivalent models of solving the device reliability, and defines a series of solving functions of reliabilities. This paper also studies the calculation method of the reliability of the network equivalent model, that is, the calculation method of the network model decomposition method. Finally, an example of reliability calculation is given to show the effectiveness of the proposed method. The results show that the proposed method can obtain the reliability value of the device.
Influence of different Milling Process on the properties of CaTiO3-NdAlO3 Dielectric Ceramics and its Microwave Devices
Authors: Ming Zhi-mao , Zhao Ke-lun , Huang Ying-ling
Published: February 2021

The high performance CaTiO3-NdAlO3 dielectric ceramics were prepared with different millingprocess. The phase composition, microstructure of the CaTiO3-NdAlO3 dielectric ceramics and dielectric properties of its microwave devices were analyzed. The results indicated that CaTiO3-NdAlO3 dielectric ceramics are single-phase orthogonal perovskite-structure. The temperature drift index of the microwave resonator manufactured by CaTiO3-NdAlO3 dielectric ceramics and the assembled cavity filter are consistent with the technical requirements of microwave resonant components and cavity filters for communication base station.
Research on Inconel 690 material test data analysis method
Authors: Chenyang Song , Jingxian Ma , Ailing Du , Qiang Liu , Xiaowei Zhang , Lechang Zhan
Published: February 2021

The quasi-static and dynamic tensile behavior of Inconel 690 alloy are studied by universal material testing machine and split-Hopkinson bar. In this paper, seven batches of nickel-based alloy samples were tested. Through these tests, the tensile stress-strain curve and tensile stress-strain rate curve of the material and the corresponding failure parameters are obtained. The Johnson-Cook (J-C) dynamic constitutive model was used to fit the experimental data by batch and non-batch analysis methods. By comparing the fitting parameters of the two analysis methods, it is possible to obtain the fitting parameters without batches. This analysis method is more suitable for the actual situation.
Incentives in Content-Sharing Network
Authors: Xu Haimei , Cheng Yan , Yang Xiuqing , Li Zhengdong
Published: February 2021

In this paper, we propose that distributed network infrastructure and curation markets based on block chain can solve major problems that have caused public tragedy in traditional content sharing networks. We also illustrate how they can incentivize a distributed content sharing system to self-evolve into a value-generating and mutually-beneficial community ecosystem with a content-sharing platform Innerlight. In this system, anyone who creates valuable things to society will get a reward and the greater the contribution is, the greater the reward is.
Review of Deployable Mechanism Test Technologies Oriented Towards Deep Space Exploration
Authors: Ye Tianyuan , Chen Zhuo , Huang Shouqing , Hu Fang
Published: February 2021

Space deployable mechanisms refer to the mechanisms that can be folded into a compact configuration and be deployed into a large predetermined shape. With the development of deep-space exploration, deployable mechanisms become one of the best choices for the deep- space probes. Large-scale, large folding ratio, high stiffness and lightweight have become the development trend of deployable mechanisms, leading to the high demands for validation of the field test. During the design and production stage, many special tests for the mission goals and the space environment need to be carried out besides the traditional spacecraft tests. In this paper, some typical tests of deployable mechanism for deep space exploration are analysed, the scheme and the performance of the special test program are summarized, such as the low gravity simulation and the vibration test. In addition, some suggestion is also made for future test methods and technology development.
Robust parametric optimization for investment casting process of a turbine vane
Authors: Ren Xia , Huang Min , Liu Xuejun
Published: February 2021

Investment casting technology is an important manufacturing technology for the turbine guide vanes of the aero-engine, which directly affects the performance of the engine. However, most of the researches on the investment casting process of the vane is mainly based on the development of the materials, while the process parameters are less researched. The purpose of this paper is to perform a robust optimization for the process parameters of the investment casting of a typical vane. Firstly, a three-dimensional casting simulation model is established based on the ProCAST® software. Five key process parameters are chosen and their uncertainties are specified. A set of desired parameters are firstly obtained by conducting a deterministic optimization using a design of experiment (DOE) method. Next, a second-order response surface model (RSM) is built with Box-Behnken design based on the initial optimization results. Finally, an RSM-based robust parametric optimization with AMGA algorithm is proposed, deriving several Pareto solutions. By comparing and analyzing every solution, an optimal parameter scheme is developed by considering high quality of the casting and robustness of the casting process.
Collision risk assessment in Jiangsu section of the Yangtze River based on evidential reasoning
Authors: He An-Xin , Zhang Jin-Fen , Zhang Di , Gan Wei-Dong
Published: February 2021

Collision between ships is one of the dominant types of accidents in the Jiangsu section of the Yangtze River, accounting for over 60% of the accidents. An evidential reasoning (ER) approach is introduced to perform a quantitative assessment of the safety of the whole waterway by dividing it into 17 sub-sections. The Risk Influencing Factors (RIFs) including channel condition, navigation environment and navigation aids conditions are considered and further decomposed into several sub-factors. The expert knowledge is used to quantify the relative importance of the RIFs to the collision risk. The historical data is used to make the Basic Probability Assignments (BPAs) of the belief structures. The hazard index (HI) is used as a measure of collision risk. The results indicate that Kouanzhi Waters and Jiaoshan Waters carry much higher collision risk than other waters, whereas Nanjing Waters and Fanjiafan Waters have the lowest collision risk. The results are useful for the maritime safety management in the Jiangsu section of the Yangtze River.
Reliability Analysis of Wheel fatigue strength based on active learning Kriging Model
Authors: Cheng Xin , Yang Xufeng
Published: February 2021

The reliability analysis of fatigue strength of rail vehicle wheels is studied in this paper. On the basis of deterministic analysis, a basic model for reliability analysis of wheel fatigue strength is established by comprehensively considering many uncertain factors. A reliability analysis method based on active learning Kriging (ALK) model is introduced to solve the fatigue strength failure probability of wheels. The results of reliability analysis are verified, and the results show that the reliability analysis based on ALK model can significantly improve the efficiency on condition the accuracy is guaranteed.
Reliability Evaluation of Bogie Assembly Process Based on FMEA-FTA
Authors: Feng Zhou , Jiankai La
Published: February 2021

Assembly is crucial in the manufacturing of complex products, and assembly quality directly affects product quality. In order to verify the assembly reliability of high-speed train bogies, taking the drive device as a research object, the assembly reliability of the drive device was evaluated and the weak links in the assembly process were obtained based on the comprehensive analysis method of FMEA-FTA. And an assembly process visualization system was developed to realize the real-time monitoring of the assembly process and improve the reliability of the assembly process. It has certain reference significance for the reliability evaluation of assembly process of similar complex products.
Impact of post annealing on the electrical properties of silver nanofilms
Authors: Udachan Shiva. L. , Ayachit N. H. , Udachan L. A , Siddanna Shivakumar , Kolkundi Shrishail. S. , Ramya S
Published: February 2021

This paper reports on the growth of nanostructures of silver films prepared by thermal evaporation in vacuum. We focused on the effect of annealing on the silver films’ electrical properties. The resistance of the sample was measured by the standard four-probe technique. The electrical resistivity data pertaining to the impact of annealing was analyzed with the help of Fuchs-Sondheimer (F-S) and Mayadas-Shatzkes (M-S) theories.
Field emission of GaN nanofilms on Si substrates enhanced by hydrogen plasma treatment
Authors: Song Zhi-Wei , Wang Changhao , Guo Gen-Cai , Yang Meng-Qi , Liang Qi , Wang Bo , Chu Wei-Guo , Wang Ru-Zhi
Published: February 2021

The (002) oriented GaN nanostructured films prepared by pulsed laser deposition (PLD) on n-type Si (100) substrates were treated by H- and O-plasma, finding both treatments do not make the sizable changes in crystalline structure and morphology of GaN nanofilms. However, the field emission (FE) performance of GaN nanofilms is considerably improved by H-plasma treatment (H-GaN) but deteriorated by O-plasma treatment (O-GaN). The turn-on fields, Eon, for H- and O-plasma treated GaN nanofilms are determined to be 0.52 and 1.79 V μm−1, respectively, in contrast with that of pristine GaN nanofilms, 0.95 V μm−1. The improvement of FE performance by the H-plasma treatments could be attributed to the reasons of the reduced surface potential barrier, the increased electron concentration, the increased surface conductivity, and the increased effective emission area. The first-principles calculations represents that the experimental and theoretical work function results have the same trend with the descending sequence of O-plasma treated GaN > pristine GaN > the H-plasma treated GaN.
Synthesis of porous Si nanoparticles for high performances anode material in lithium-ion batteries
Authors: Yang Feng , Dai Yulong , Peng Dehuai , Huang Kai
Published: February 2021

As one of the most promising candidates for anode materials, Si-based electrodes can offer specific capacity an order of magnitude beyond that of conventional graphite. However, Si usually suffers from dramatic volume changes during cycling cause pulverization and capacity fade. The key to improving cycle life is to synthesize Si-based materials with suitable architectures and a rational design. Here, we developed an economical and efficient method to obtain porous Si nanoparticles from coal ash. The Si nanoparticles with several nanometers can significantly shorten ion/electron transportation paths and further avoid the cracking and pulverization induced by large volume changes, and the porous structure makes the penetration of electrolyte easier. After carbonization, the obtained porous Si nanoparticles@C exhibits excellent electrochemical performances, and the special capacity can stable at 750 mAh g−1 at 2.0 A g−1 after 200 cycles. When current density up to 6.0 A g−1, the reversible capacity is 565 mAh g−1. We believe this method will make it possible to facilitate the large-scale and low-cost production of porous Si nanoparticles, and contribute to the development of high-performance Si-based anode materials.
Nb-based superconducting silicon interconnect fabric for cryogenic electronics
Authors: Yang Yu-Tao , Hu Chaowei , Zhang Peng , Shakoorzadeh Niloofar , Ni Ni , Wang Kang L , Iyer Subramanian S
Published: February 2021

Quantum computing for real world applications requires large arrays of qubits. This requires advanced integration technologies. In this work, we propose a simple integration method with fine interconnect pitch (10 μm) and close spacing that can overcome the large input and output (I/O) and high wiring level requirements of very large scale of quantum circuits. A system-on-wafer (SoW) packaging concept called superconducting silicon interconnect fabric (superconducting-IF), based on silicon interconnect fabric (Si-IF), is proposed, with the help of a Au interlayer technology onto the superconducting-IF. The fine-pitch and die-to-wafer-scale Au interlayer is the first demonstration of direct metal–metal thermocompression bonding (TCB) that is optimized for superconducting applications without the use of solders. The developed Au interlayer integration technology is demonstrated to be Josephson-junction-compatible (<150 °C), mechanically robust (>30 MPa), and electrically reliable down to 2 K. The mechanical strength of the Au interlayer integration method is optimized through shear tests with a shear force around 150 N on 2 × 2 mm2 dies. The transition temperature (Tc) of Nb, which is at 9 K, is experimentally verified to be unchanged after each fabrication process. Electrical and temperature cycling measurements on over 20 bonded dies of large-pitch Kelvin structures as well as fine-pitch daisy chain structures reveal reliable connections in the low-temperature regime. This work pushes quantum computing a step closer to realize its potential through 3D integration of a very large scale of quantum circuits with a high density of I/O (>10 000 per mm2) as well as high wiring capability and without introducing lossy amorphous dielectrics.
Printable and flexible wireless oxygen sensor
Authors: Rongala Amith , Khuje Saurabh , Li Zheng , Chivate Aditya , Gogoi Pratahdeep , An Lu , Ren Shenqiang
Published: February 2021

The sensor devices are becoming an essential aspect of electronics, while an accurate, economical, and printable device is constantly in high demand. Particularly, it is indispensable to develop the printed flexible sensor electronics with a fast response time, high sensitivity, and selectivity, as well as hybrid scalable manufacturing at a low cost. Here we demonstrate a printable and flexible oxygen amperometric sensor capable of operating at room temperature, in which the printed metal features are homogenously interlinked to form a dense and highly conductive mesh structure followed by a flexible hydrogel electrolyte layer. The printed oxygen sensor shows a response time of less than 2 s with a sensor response of 94.6% and the oxygen gas detection levels as low as 1.56 ppm. The sensing attributes of the printed devices with the added wireless feature show an immense promise for monitoring the oxygen levels, which provide a new rapid-sensing pathway for the packaging processes and remote monitoring devices for averting hazardous conditions.
Exploration of transferable and uniformly accurate neural network interatomic potentials using optimal experimental design
Authors: Zaverkin Viktor , Kästner Johannes
Published: February 2021

Machine learning has been proven to have the potential to bridge the gap between the accuracy of ab initio methods and the efficiency of empirical force fields. Neural networks are one of the most frequently used approaches to construct high-dimensional potential energy surfaces. Unfortunately, they lack an inherent uncertainty estimation which is necessary for efficient and automated sampling through the chemical and conformational space to find extrapolative configurations. The identification of the latter is needed for the construction of transferable and uniformly accurate potential energy surfaces. In this paper, we propose an active learning approach that uses the estimated model’s output variance derived in the framework of the optimal experimental design. This method has several advantages compared to the established active learning approaches, e.g. Query-by-Committee, Monte Carlo dropout, feature and latent distances, in terms of the predictive power and computational efficiency. We have shown that the application of the proposed active learning scheme leads to transferable and uniformly accurate potential energy surfaces constructed using only a small fraction of data points. Additionally, it is possible to define a natural threshold value for the proposed uncertainty metric which offers the possibility to generate highly informative training data on-the-fly.
Drug release from polymer-coated TiO2 nanotubes on additively manufactured Ti-6Al-4V bone implants: a feasibility study
Authors: Micheletti Chiara , Suriano Raffaella , Grandfield Kathryn , Turri Stefano
Published: February 2021

Insufficient osseointegration, inflammatory response and bacterial infection are responsible for the majority of bone implant failures. Drug-releasing implants subjected to adequate surface modification can concurrently address these challenges to improve the success of implant surgeries. This work investigates the use of Ti-6Al-4V (Ti64) with a dual-scale surface topography as a platform for local drug delivery. Dual-scale topography was obtained combining the inherent microscale roughness of the Ti64 samples manufactured by selective laser melting (SLM) with the nanoscale roughness of TiO2 nanotubes (TNTs) obtained by subsequent electrochemical anodization at 60 V for 30 min. TNTs were loaded with a solution of penicillin-streptomycin, a common antibiotic, and drug release was tested in vitro. Three biocompatible and biodegradable polymers, i.e. chitosan, poly(ε-caprolactone) and poly(3-hydroxybutyrate), were deposited by spin coating, while preserving the microscale topography of the substrate underneath. The presence of polymer coatings overall modified the drug release pattern, as revealed by fitting of the experimental data with a power-law model. A slight extension in the overall duration of drug release (about 17% for a single layer and 33% for two layers of PCL and PHB) and reduced burst release was observed for all polymer-coated samples compared to uncoated, especially when two layers of coatings were applied.
DNAJB12 and Hsp70 triage arrested intermediates of N1303K-CFTR for endoplasmic reticulum-associated autophagy
Authors: He Lihua , Kennedy Andrew S. , Houck Scott , Aleksandrov Andrei , Quinney Nancy L. , Cyr-Scully Alexandra , Cholon Deborah M. , Gentzsch Martina , Randell Scott H. , Ren Hong Yu , Cyr Douglas M.
Published: February 2021

Transmembrane Hsp40s and cytosolic Hsp70 cooperate on the endoplasmic reticulum’s (ER) cytoplasmic face to facilitate the triage of nascent polytopic membrane proteins. DNAJB12 is reported to operate in biosynthetically active ER microdomains to mediate degradation of ER-associated degradation-resistant membrane protein intermediates by selective ER-associated autophagy.
Oropharyngeal dysphagia in older patients with hip fracture
Authors: Mateos-Nozal Jesús , Sanchez Garcia Elisabet , Romero Rodríguez Estela , Cruz-Jentoft Alfonso J
Published: February 2021

Background

oropharyngeal dysphagia (OD) and hip fracture are common problems in older patients, both associated with important complications.

Objective

the aim of this study was to measure the prevalence and identify the main risk factors of dysphagia in older patients with hip fracture.

Design

a prospective study in an orthogeriatric unit of a university hospital over 10 months.

Methods

a total of 320 patients (mean age 86.2 years, 73.4% women) were assessed for dysphagia within 72 hours post-surgery using the Volume-Viscosity Swallow Test. Geriatric assessment, hip fracture management and complications were examined to determine their relationship with the presence of OD.

Results

dysphagia was present in 176 (55%) patients. Multivariate logistic regression analysis showed that the presence of delirium during hospitalization and the inability to perform instrumental activities of daily living before admission were associated with OD.

Conclusions

the prevalence of OD is high in hip fracture patients. Objective dysphagia assessment should be routinely included as part of the geriatric assessment of such patients.
Interpregnancy Interval and Subsequent Severe Maternal Morbidity: A 16-Year Population-Based Study From California
Authors: Liu Can , Snowden Jonathan M , Lyell Deirdre J , Wall-Wieler Elizabeth , Abrams Barbara , Kan Peiyi , Stephansson Olof , Lyndon Audrey , Carmichael Suzan L
Published: February 2021

Interpregnancy interval (IPI) is associated with adverse perinatal outcomes, but its contribution to severe maternal morbidity (SMM) remains unclear. We examined the association between IPI and SMM, using data linked across sequential pregnancies to women in California during 1997–2012. Adjusting for confounders measured in the index pregnancy (i.e., the first in a pair of consecutive pregnancies), we estimated adjusted risk ratios for SMM related to the subsequent pregnancy. We further conducted within-mother comparisons and analyses stratified by parity and maternal age at the index pregnancy. Compared with an IPI of 18–23 months, an IPI of <6 months had the same risk for SMM in between-mother comparisons (adjusted risk ratio (aRR) = 0.96, 95% confidence interval (CI): 0.91, 1.02) but lower risk in within-mother comparisons (aRR = 0.76, 95% CI: 0.67, 0.86). IPIs of 24–59 months and ≥60 months were associated with increased risk of SMM in both between-mother (aRR = 1.18 (95% CI: 1.13, 1.23) and aRR = 1.76 (95% CI: 1.68, 1.85), respectively) and within-mother (aRR = 1.22 (95% CI: 1.11, 1.34) and aRR = 1.88 (95% CI: 1.66, 2.13), respectively) comparisons. The association between IPI and SMM did not vary substantially by maternal age or parity. In this study, longer IPI was associated with increased risk of SMM, which may be partly attributed to interpregnancy health.
Revolutionary Criminal Punishments: Treason, Mercy, and the American Revolution
Authors: Jouet Mugambi
Published: January 2021

This article focuses on the exceptional mildness of criminal punishments for alleged traitors in the wake of the American Revolution. American leaders were disinclined to inflict the death penalty on loyalists who supported British rule in the revolutionary war or on insurgents in the Shays, Whiskey, and Fries rebellions shortly after independence. In fact, the Founding Fathers and other first-generation officials commonly showed remarkable mercy. Numerous “traitors” readily rehabilitated themselves by recognizing their faults, swearing an oath of allegiance to the new American republic, and promising to refrain from further wrongdoing. These revolutionary punishments were a striking prefiguration of modern penal practices: guilty pleas, probation sentences, and rehabilitation policies aiming to reintegrate wrongdoers into society. While American revolutionary punishments comprised stark racial inequities and did not constitute a lost utopia, they were particularly mild for the period. In contrast, the contemporary French Revolution led to wide-scale executions of purported traitors. Besides shedding light on historic events that criminal justice scholars have neglected, the article’s findings are relevant to ongoing debates about American exceptionalism and the peculiar harshness of modern American justice, including originalist and non-originalist interpretations of the Eighth Amendment. The rise of mass incarceration in the United States and its retention of the death penalty can foster cultural essentialism about how American culture traditionally lacks humanistic sensibilities. In reality, the revolutionary criminal punishments of the late eighteenth century demonstrate how America was once a trailblazer in embracing humane conceptions of justice.
Action Levels for the Prevention of Work-Related Musculoskeletal Disorders in the Neck and Upper Extremities: A Proposal
Authors: Arvidsson Inger , Dahlqvist Camilla , Enquist Henrik , Nordander Catarina
Published: February 2021

There are several well-known risk factors for work-related musculoskeletal disorders (MSDs). Despite this knowledge, too many people still work in harmful conditions. The absence of occupational exposure limits (OELs) for physical workload impedes both supervision and preventive work. To prevent myalgia, tendon disorders, and nerve entrapments in the upper musculoskeletal system, we propose action levels concerning work postures, movement velocities and muscular loads recorded by wearable equipment. As an example, we propose that wrist velocity should not exceed 20°/s as a median over a working day. This has the potential to reduce the prevalence of carpal tunnel syndrome (CTS) in highly exposed male occupational groups by 93%. By reducing upper arm velocity in highly exposed female groups to the suggested action level 60°/s, the prevalence of pronounced neck/shoulder myalgia with clinical findings (tension neck syndrome) could be reduced by 22%. Furthermore, we propose several other action levels for the physical workload. Our ambition is to start a discussion concerning limits for physical workload, with the long-term goal that OELs shall be introduced in legislation. Obviously, the specific values of the proposed action levels can, and should, be discussed. We hope that quantitative measurements, combined with action levels, will become an integral part of systematic occupational health efforts, enabling reduction and prevention of work-related MSDs.
Enhanced growth and myogenic differentiation of spheroid-derived C2C12 cells
Authors: Jin Guang-Zhen
Published: February 2021

Among many factors of controlling stem cell differentiation, the key transcription factor upregulation via physical force is a good strategy on the lineage-specific differentiation of stem cells. The study aimed to compare growth and myogenic potentials between the parental cells (PCs) and the 1-day-old C2C12 spheroid-derived cells (SDCs) in two-dimensional (2D) and three-dimensional (3D) culture conditions through examination of the cell proliferation and the expression of myogenic genes. The data showed that 1-day-old spheroids had more intense expression of MyoD gene with respect to the PCs. The proliferation of the SDCs is significantly higher than the PCs in a time-dependent manner. The SDCs had also significantly higher myogenic potential than the PCs in 2D and 3D culture conditions. The results suggest that MyoD gene upregulation through cell–cell contacts is the good approach for preparation of seed cells in muscle tissue engineering.