Reliability modeling of mutual DCFP considering failure physical dependency

Degradation and overstress failures occur in many electronic systems in which the operation load and environmental conditions are complex.The dependency of them called dependent competing failure process(DCFP),has been widely studied.Electronic system may experience mutual effects of degradation and shocks,they are considered to be interdependent.Both the degradation and the shock processes will decrease the limit of system and cause cumulative effect.Finally,the competition of hard and soft failure will cause the system failure.Based on the failure mechanism accumulation theory,this paper constructs the shock-degradation acceleration and the threshold descent model,and a system reliability model established by using these two models.The mutually DCFP effect of electronic system interaction has been decomposed into physical correlation of failure,including acceleration,accumulation and competition.As a case,a reliability of electronic system in aeronautical system has been analyzed with the proposed method.The method proposed is based on failure physical evaluation,and could provide important reference for quantitative evaluation and design improvement of the newly designed system in case of data deficiency.

Research on the Design and Implementation of Middle School Physical Education Curriculum Based on the Process Model

For a long time,the education work in China has been deeply affected by the target model.With the development of the times and the continuous reform of education,the impact of process model on education has become increasingly prominent.It does not only give full play to the internal value of the curriculum content,but also cultivate students5 personality and subjectivity.Taking the middle school physical education curriculum design as an example,this paper explores the practical application of process model for reference.

Simulation Experiments of Land Surface Physical Processes and Ecological Effect over Different Underlying Surface

Based on the existing Land Surface Physical Process Models(Deardorff, Dickinson, LIU, Noilhan, Seller, ZHAO), a Comprehensive Land Surface Physical Process Model (CLSPPM) is developed by considering the different physical processes of the earth's surface-vegetation-atmosphere system more completely. Compared with SiB and BATS, which are famous for their detailed parameterizations of physical variables, this simplified model is more convenient and saves much more computation time. Though simple, the feas...

Relative importance of different physical processes on upper crustal specific heat flow in the Eifel-Maas region, Central Europe and ramifications for the production of geothermal energy

We study the recent upper crustal heat flow variations caused by long-term physical processes such as paleoclimate, erosion, sedimentation and mantle plume upwelling. As specific heat flow is a common lower boundary condition in many models of heat en fluid flow in the Earth’s crust we quantify its long-term transient variation caused by paleoclimate, erosion or sedimentation, mantle plume upwelling and deep groundwater flow. The studied area extends between the Eifel mountains and the Maas river inCentral Europe. The total variation due to these processes in our study area amounts to tectonic events manifested in the studied area 20 mW/m2, about 30% of the present day specific heat flow in the region.

A weakly coupled data assimilation system of a coupled physical–biological model for the northeastern South China Sea

南海东北部沿岸海域在每年夏季都存在显著的物理过程(如上升流,珠江冲淡水)和活跃的生物过程,这些基本的物理场和生物场要素对沿岸海域的研究起关键作用。本文在一适应于南海东北部的物理生物耦合模式的基础上建立了一个弱约束的EnOI耦合同化系统。开展的SST同化试验结果表明,物理过程存在合理的响应,且近海上升流区的海洋生态变量对物理变量的同化也有响应。

PHSICAL MODELLING AND PROCESSING OF Ti-6Al-4V ELI

Titanium has been widely used as the implant materials of joint prostheses. This paper simulates the microstructures of the hot forged titanium knee joint component by physical modeling. Ti-6Al-4V ELI were deformed by GLEEBLE 2000 hot deforma- tion simulator in compression mode to determine the hot workability, in the range of 900 to 1100℃, with the strain rates between 0.05 to 5 s^(-1). Test results derived from specimens processed by on-cooling test and on-heating test were compared, thereby estimating the effect due to thermal history. The forging process of Ti-6Al-4V ELI tibial base plate of knee joint prostheses was design based on the workability data obtained.

中小学校课后体育服务开展的审视与调适--基于史密斯政策执行过程模型分析

运用文献资料、逻辑分析等方法,基于史密斯政策执行过程模型分析中小学校课后体育服务开展困境,并提出调适策略。困境:政策体系建设滞缓,执行标准模糊;执行主体联动不畅,执行监督不力;目标群体趋向私利,执行态度偏离;执行环境基础薄弱,资源保障不足。调适策略:加快政策体系构建,细化政策执行标准;加强执行主体联动,提高政策监管力度;增强目标群体观念,建立有效激励机制;优化政策实施环境,拓宽执行资源渠道。

考虑水力耦合作用的降雨诱发土质滑坡过程数值模拟研究

为探究水力耦合作用对降雨诱发土质滑坡过程的影响机理,从边坡失稳和滑坡运动2个方面进行综合分析。结合Richards模型和无限边坡模型描述降雨入渗条件下土质边坡含水率、基质吸力及稳定安全系数演化,采用Iverson-George模型描述土质滑坡运动过程中内部孔压、速度及厚度演化,通过模拟土体非饱和入渗实验及深圳光明新区滑坡验证了模型的适用性;以含水率为衔接因子将降雨诱发土质边坡渐进失稳到滑坡运动相耦合,搭建可考虑水力耦合作用下降雨诱发土质滑坡全过程的数值模拟流程。结果表明:同一初始条件下,土体渗透系数越小,滑坡运动能力越强,土体趋于饱和时含水率越大,滑坡运动能力越强,相比于渗透系数而言土体含水率对滑坡运动影响程度较大。为描述水力耦合作用下降雨诱发土质滑坡过程提供了一种定量化的数值方法。

面向智能汽车赛博物理系统的领域特定建模语言研究

智能汽车信息物理系统(IVCPS)是具有多领域交叉融合特征的复杂大系统,在设计IVCPS领域特定建模语言时,应用现有建模语言存在扩展性差、成熟度低、学习成本高等问题,因此,本文根据V模型和创新架构方法,分别从IVCPS顶层设计流程、IVCPS元语言对象集语言要素定义两部分对面向IVCPS领域特定建模语言(DSML)进行研究,对IVCPS系统层元语言和组件化元语言的规范化进行定义,研究赛博物理组件中表达物理实现、动态特性和赛博计算的组件,以期为赛博物理组件的封装和创建提供参考。

运用GMS算法自动识别相似模拟材料实验裂隙场

通常采用沙盘物理模型与近距离摄影测量相结合的方法来探索上覆地层的断裂机制,但由于沙土物理模型裂缝图像的信噪比较低,该算法往往提取得不完整。鉴于此,提出了一种基于计算机视觉的图像梯度原理、图像匹配和区域筛选技术(GMS算法)的裂隙检测算法。首先利用峰峰市九龙煤矿15235工作面的钻孔柱状图建立沙盘物理模型;再利用定焦数码相机拍摄该模型的正射影像;最后根据模型图像的纹理特征,分别采用图像匹配技术、区域筛选技术分割规则的大面积非裂缝纹理和微小非裂缝纹理。研究结果表明,GMS算法具有很强的抗干扰能力,能准确识别并自动提取相似模拟材料中上覆地层的裂隙场。

Multi-year Simulations and Experimental Seasonal Predictions for Rainy Seasons in China by Using a Nested Regional Climate Model (RegCM_NCC). Part Ⅰ: Sensitivity Study

A modified version of the NCAR/RegCM2 has been developed at the National Climate Center （NCC）, China Meteorological Administration, through a series of sensitivity experiments and multi-year simulations and hindcasts, with a special emphasis on the adequate choice of physical parameterization schemes suitable for the East Asian monsoon climate. This regional climate model is nested with the NCC/IAP （Institute of Atmospheric Physics） T63 coupled GCM to make an experimental seasonal prediction for China and East Asia. The four-year （2001 to 2004） prediction results are encouraging. This paper is the first part of a two-part paper, and it mainly describes the sensitivity study of the physical process paraxneterization represented in the model. The systematic errors produced by the different physical parameterization schemes such as the land surface processes, convective precipitation, cloud-radiation transfer process, boundary layer process and large-scale terrain features have been identified based on multi-year and extreme flooding event simulations. A number of comparative experiments has shown that the mass flux scheme （MFS） and Betts-Miller scheme （BM） for convective precipitation, the LPMI （land surface process model I） and LPMII （land surface process model Ⅱ） for the land surface process, the CCM3 radiation transfer scheme for cloud-radiation transfer processes, the TKE （turbulent kinetic energy） scheme for the boundary layer processes and the topography treatment schemes for the Tibetan Plateau are suitable for simulations and prediction of the East Asia monsoon climate in rainy seasons. Based on the above sensitivity study, a modified version of the RegCM2 （RegCM_NCC） has been set up for climate simulations and seasonal predictions.

Modeling and analysis of the ocean dynamic with Gaussian complex network

The techniques for oceanographic observation have made great progress in both space-time coverage and quality, which make the observation data present some characteristics of big data. We explore the essence of global ocean dynamic via constructing a complex network with regard to sea surface temperature. The global ocean is divided into discrete regions to represent the nodes of the network. To understand the ocean dynamic behavior, we introduce the Gaussian mixture models to describe the nodes as limit-cycle oscillators. The interacting dynamical oscillators form the complex network that simulates the ocean as a stochastic system. Gaussian probability matching is suggested to measure the behavior similarity of regions. Complex network statistical characteristics of the network are analyzed in terms of degree distribution, clustering coefficient and betweenness. Experimental results show a pronounced sensitivity of network characteristics to the climatic anomaly in the oceanic circulation. Particularly, the betweenness reveals the main pathways to transfer thermal energy of El Niño–Southern oscillation. Our works provide new insights into the physical processes of ocean dynamic, as well as climate changes and ocean anomalies.

Energy Balance-Based SWAT Model to Simulate the Mountain Snowmelt and Runoff——Taking the Application in Juntanghu Watershed(China) as an Example

In order to predict long-term flooding under extreme weather conditions in central Asia, an energy balance-based distributed snowmelt runoff model was developed and coupled with the Soil and Water Assessment Tool(SWAT) model. The model was tested at the Juntanghu watershed on the northern slope of the Tian Shan Mountains, Xinjiang,China. We compared the performances of temperature-index method and energy balanced method in SWAT model by taking Juntanghu river basin as an application example(as the simulation experiment was conducted in Juntanghu River, we call the energy balanced method as SWAT-JTH). The results suggest that the SWAT snowmelt model had overall Nash-Sutcliffe efficiency(NSE) coefficients ranging from 0.61 to 0.85 while the physical based approach had NSE coefficients ranging from 0.58 to0.69. Overall, on monthly scale, the SWAT model provides better results than that from the SWAT-JTH model. However, results generated from both methods seem to be fairly close at a daily scale. Thestructure of the temperature-index method is simple and produces reasonable simulation results if the parameters are well within empirical ranges. Although the data requirement for the energy balance method in current observation is difficult to meet and the existence of uncertainty is associated with the experimental approaches of physical processes, the SWAT-JTH model still produced a reasonably high NSE. We conclude that using temperature-index methods to simulate the snowmelt process is sufficient, but the energy balance-based model is still a good choice to simulate extreme weather conditions especially when the required data input for the model is acquired.

Mechanical response features and failure process of soft surrounding rock around deeply buried three-centered arch tunnel

Due to the extreme complexity of mechanical response of soft surrounding rock(SR) around a tunnel under high geostatic stress conditions, the integration of physical and numerical modeling techniques was adopted. Based on the similarity theory, new composite-similar material was developed, which showed good agreement with the similarity relation and successfully simulated physico-mechanical properties(PMP) of deep buried soft rock. And the 800 mm×800 mm×200 mm physical model(PM) was conducted, in which the endoscopic camera technique was adopted to track the entire process of failure of the model all the time. The experimental results indicate that the deformation of SR around a underground cavern possessed the characteristics of development by stages and in delay, and the initial damage of SR could induce rapid failure in the later stage, and the whole process could be divided into three stages, including the localized extension of crack(the horizontal load(HL) was in the range of 130 k N to 170 k N, the vertical load(VL) was in the range of 119 k N to 153.8 k N), rapid crack coalescence(the HL was in the range of 170 k N to 210 k N, the VL was in the range of 153.8 k N to 182.5 k N) and residual strength(the HL was greater than 210 k N, the VL was greater than 182.5 k N). Under the high stress conditions, the phenomenon of deformation localization in the SR became serious and different space positions show different deformation characteristics. In order to further explore the deformation localization and progressive failure phenomenon of soft SR around the deeply buried tunnel, applying the analysis software of FLAC3 D three-dimensional explicit finite-difference method, based on the composite strain-softening model of Mohr-Coulomb shear failure and tensile failure, the calculation method of large deformation was adopted. Then, the comparative analysis between the PM experiment and numerical simulation of the three centered arch tunnels was implemented and the relationship of deformation localization and progressive failure of SR around a tunnel under high stress conditions was discussed.

Research on 2D Model of Capillary Discharge Plasma

The physical process of capillary discharge in a PE tube utilized in electro-thermal-chemical(ETC)guns was investigated.ETC guns can enhance the ignition and combustion of propellant in order to reduce the ignition delay and increase muzzle velocity of the projectile.A key component in ETC gun is the capillary plasma source.In this paper,a 2D steady state model of discharge was built by using magnetic hydrodynamics method.It took the plasma energy balance,material ablation,mass and momentum conservations in a quasi-neutral plasma region into account.Also,the effect of different compositions and PE concentration distribution were considered.In order to evaluate the validation of this model,the simulation results are compared with former works.

MoM-PO/SBR Algorithm Based on Collaborative Platform and Mixed Model

For electromagnetic scattering of 3?D complex electrically large conducting targets,a new hybrid algorithm,MoM?PO/SBR algorithm,is presented to realize the interaction of information between method of moment(MoM)and physical optics(PO)/shooting and bouncing ray(SBR).In the algorithm,the COC file that based on the Huygens equivalent principle is introduced,and the conversion interface between the equivalent surface and the target is established.And then,the multi?task flow model presented in this paper is adopted to conduct CPU/graphics processing unit(GPU)tests of the algorithm under three modes,i.e.,MPI/OpenMP,MPI/compute unified device architecture(CUDA)and multi?task programming model(MTPM).Numerical results are presented and compared with reference solutions in order to illustrate the accuracy and the efficiency of the proposed algorithm.

Mathematical Modeling of Heat Flux Distribution in Raw Cotton Stored in Bunt

The scientific article examines the physical and mechanical properties of raw cotton stored in buntings in cotton palaces. Because during the storage of raw cotton in bunts, some of its properties deteriorate, some improvements. Therefore, the mathematical modeling of storage conditions of raw cotton in bunts and the physical and mechanical conditions that occur in it is of great importance. In the developed mathematical model, the main factor influencing the physical and mechanical properties of raw cotton is the change in temperature. Due to the temperature, kinetic and biological processes accumulated in the raw cotton in Bunt, it can spread over a large surface, first in a small-local state, over time with a nonlinear law. As a result, small changes in temperature lead to a qualitative change in physical properties. In determining the law of temperature distribution in the raw cotton in Bunt, Laplace’s differential equation of heat transfer was used. The differential equation of heat transfer in Laplace’s law was replaced by a system of ordinary differential equations by approximation. Conditions are solved in MAPLE-17 program by numerical method. As a result, graphs of temperature changes over time in raw cotton were obtained. In addition, the table shows the changes in density, pressure and mass of cotton, the height of the bun. As the density of the cotton raw material increases from the top layer of the bunt to the bottom layer, an increase in the temperature in it has been observed. This leads to overheating of the bottom layer of cotton and is the main reason for the deterioration of the quality of raw materials.

高校德体美劳过程性评价研究

加强高校德体美劳过程性评价,是深化新时代教育评价改革的重大现实需要。当前,高校德体美劳过程性评价存在价值取向偏差、评价指标单一、多主体协同不足、学生参与度不高、评价结果运用不充分以及持续改进质量文化尚未形成等问题。课程是高校开展德体美劳教育的核心载体,课外活动是内化课程教学效果的重要途径;课程教学与课外活动相互支撑,构成完整的德体美劳教育活动。为推进高校德体美劳过程性评价改革,应充分发挥教育行政部门、高校、教师、学生四类主体的协同作用,聚焦课程与活动两个场域,借鉴CIPP评价模型,从总体规划、综合改革、发展目标、学生发展需求等四个方面对情境要素进行评价;从队伍建设、课程建设或活动组织、设施条件、组织制度保障等四个方面对输入要素进行评价;从价值感、热情度、清晰度、活跃度、师生关系、内容广度、考试考核、材料与练习、总体反馈等九个方面对过程要素进行评价;从实施影响、成本效益、可持续性、可推广性四个方面对产出要素进行评价。为推进这一过程性评价的落实,高校应充分关注德体美劳过程性评价伦理、加强德体美劳教育投入、注重提升教师评价素养以及引导学生主动深度参与。

基于AHP层次分析法对物理模型体系构建研究

层次分析法(AHP)是构建物理模型体系的有效研究方法.主要介绍了AHP算法的基本原理,并利用AHP算法对物理课程的评价指标体系和中学生综合素质评价指标体系进行了重构,建立了物理课程评价体系模型和中学生综合素质评价体系模型,并进行了一致性检验.结果表明各指标一致性检验比率均小于0.1,各指标总体权重值可作为物理学(师范)专业人才培养课程体系评价,以及中学生综合素质评价的决策依据.两种物理模型体系符合OBE教学理念,较以往单一的评价方式更加客观、科学、有效.

社区邻里社会环境如何影响居民体育锻炼行为:双重过程模型视角的实证分析

基于双重过程模型对3896名社区居民进行问卷调查,从锻炼情绪角度探讨社区邻里社会环境影响居民体育锻炼行为的过程机制。结果表明:社区邻里社会环境显著正向影响居民体育锻炼行为;调和式热情部分中介社区邻里社会环境与居民体育锻炼行为的关系,而强迫式热情的中介效应不显著;锻炼认同正向调节社区邻里社会环境与居民调和式热情、强迫式热情的关系;锻炼认同调节社区邻里社会环境通过调和式热情对居民体育锻炼行为影响的中介过程,从而起着有中介的调节效应,而在强迫式热情中介社区邻里社会环境与居民体育锻炼行为的关系中,锻炼认同的调节效应不显著。研究拓展了社区邻里社会环境影响居民体育锻炼行为的中介机制与边界条件,提示社区在提升整体邻里社会环境时需要营造积极活跃的锻炼氛围来强化居民锻炼认同感,从而提升调和式热情体验,以便能更好地促进其参与体育锻炼。