Evaluation of the Fatigue Characteristics of Laser-processed Hot Work Tool Steel Based on Reliability

It is reported that laser-processing is effective to repair the heat checks, which are fine shallow cracks on a surfaceof die-casting dies. In this study, the rotating bending fatigue tests have been carried out to evaluate the fatiguecharacteristics of laser-processed hot working tool steel. Because test results are scattered, S-N curves are decidedbased on the evaluation of fatigue strength distribution. As a result, the fatigue strength of the laser-processedspecimens decreases remarkably in comparison with that of base metal. However, it can be recovered to almostinitial value by heat treatment at secondary hardening temperature. This procedure is also effective to decrease thescatter of fatigue strength. The laser-processing can be carried out at low cost and this method is effective for theextension of the work life of dies.

Assessment of Multiple Working Condition System Reliability with Agent-Based Simulation Method

The mission reliability assessment plays a great role in logistics planning and supporting resource optimization of complex system.But the current problem,which is difficult to solve,is how to model and analyze the characters of system reliability under the complex mission profile.In order to solve the problem,an agentbased simulation method was used to assess reliability for complex systems with various random working conditions.A multi-working condition simulation agent(MA)was designed and used to simulate the random transferring process of working conditions of system,and it cooperated with system simulation agents(SAs)and unit simulation agents(UAs)to realize system mission reliability(MR)simulation.Through simulation experiments,effect of multiple working conditions mission on the reliability of system was analyzed by comparing with the basic reliability condition.Feasibility and efficiency of the method were proved through simulation experiments of the case system.The research result provides a viable and useful method and a solution for MR analysis and assessment of complex systems in multi-working conditions,which can help to evaluate the reliability of operating system orienting to the practical mission and environment,and it is meaningful for the reliability analysis and the design of complex systems.

Reliability analysis of torpedo loading based on fractional-order optimization model

A fractional-order cumulative optimization GM(1,2)model based on grey theory is proposed to study the relationship between torpedo loading and working reliabilities.In this model,the average relative error function related to order and background value is established.Taking the average relative error function as the objective function,the optimal value of the two parameters is obtained through the optimization method,and the minimum value of the average relative error is determined.The calculation example shows that this method can greatly improve the accuracy of the model and more accurately reflect the relationship between torpedo loading and working reliabilities compared with the traditional GM(1,2)model.

基于允许可靠度的薄壁圆筒静强度安全系数

为建立钢制单层承压薄壁圆筒静强度的可靠性设计技术,当圆筒静强度与载荷分别符合正态分布且静强度分布参数为区间值时,应用概率论知识,构建了圆筒静强度在不同工况的可靠度系数、安全系数和工况系数三者之间的关系。研究表明:1)在一般气压试验或气液组合试验时,圆筒屈服强度的允许可靠度系数应不小于1.549且不超过2.115,爆破强度的允许可靠度系数应不小于4.081且不超过5.414。2)在一般液压试验时,圆筒屈服强度的允许可靠度系数应不小于0.605且不超过1.005,爆破强度的允许可靠度系数应不小于3.304且不超过4.430。3)在正常操作时,圆筒屈服强度的允许可靠度系数应不小于1.961且不超过2.484,爆破强度的允许可靠度系数应不小于4.280且不超过5.456。4)在允许可靠度系数满足上述取值范围,且工况系数符合中国标准时,圆筒屈服安全系数可取1.40,爆破安全系数可取2.00。

基于GMM的流体旋转设备运行可靠性在线评价方法

针对流体旋转设备运行工况多变且难以区分,导致运行可靠性评价准确率低的问题,提出了一种基于高斯混合模型(GMM)的流体旋转设备运行可靠性在线性评价方法。首先,根据设备历史运行数据,基于快速搜索和发现密度峰值的聚类算法(DPC),进行工况划分,构建不同工况条件下的基于GMM的运行可靠性基准模型;其次,使用XGBoost算法对设备实时运行状态进行工况识别,约减冗余指标,构建设备运行可靠性的评价指标体系;然后,计算度量评价指标与对应工况下基准模型指标的偏离程度,以马氏距离作为度量标准,进一步计算得到设备运行可靠性评价指数;最后,以矿用离心机设备为例,进行了多工况下的运行可靠性实例分析和模型验证。研究结果表明,该方法能够在线实时反应设备当前的运行可靠性水平,当离心机设备运行可靠性低于0.857时,认为设备进入劣化状态,且评价准确率达到98%以上。

液压支架结构的可靠性设计研究

针对国内液压支架在结构件可靠性方面与国外产品的差距,依托2套出口支架产品,阐述了应用于中厚煤层高工作阻力液压支架的顶梁底座柱窝、掩护梁、连杆的抗弯、抗扭性结构设计,对这些结构的技术特征、创新性、应用范围进行了分析研究。2套出口支架顺利通过了按美国CONSOL标准进行的60 000次型式试验,试验结果表明,所述结构切实提高了支架的抗弯、抗扭性能,提高了液压支架的可靠性。

支路开关自放电对大型多路并联FLTD脉冲源可靠性的影响

快脉冲直线型变压器驱动源(fast linear transformer driver,FLTD)是建设下一代大型Z箍缩装置最有前景的技术路线之一。大型FLTD脉冲源中数以万计气体开关的可靠运行是提高Z箍缩装置可靠性的重要因素。该文基于15 MAZ箍缩科学实验装置的FLTD脉冲源设计,采用Monte-Carlo方法建立考虑支路开关自放电及其载荷共享效应的FLTD脉冲源可靠性计算模型,分析开关故障模式及其触发策略对脉冲源可靠性的影响。结果表明,主支路开关自放电产生的故障电压会引起开关级联自放电,降低装置可靠性。若主支路开关工作系数设定在0.5~0.7范围内,FLTD脉冲源故障率可低于1×10^(-4)。此外,触发器及触发支路开关的高可靠性对于提升脉冲源可靠性至关重要,增加触发器脉冲数量、降低触发器自放电故障率能够有效提升脉冲源可靠性,当触发器脉冲数量提升至4倍后,FLTD脉冲源故障率有望降低至1×10^(-5)以下。研究结果为大型FLTD脉冲源的开关工作系数及触发策略的选取提供参考,具有重要的工程应用价值。

工作-生活平衡量表在护士工作-生活平衡状态中的应用评价

目的探讨工作-生活平衡量表用于测评护士工作-生活平衡状态的信度和效度,为调查护士工作-生活平衡状态提供科学、严谨的测评工具。方法2023年2月1日至3月1日使用工作-生活平衡量表对广西医科大学第一附属医院、广西医科大学第二附属医院、广西医科大学附属武鸣医院3所三甲医院具有临床工作经验1年及以上的526名护士进行测定,并对测评结果进行信效度检验。结果总量表Cronbach′s α系数为0.940,分半信度为0.881;3个因子内部Cronbach′s α系数为0.819~0.930,折半信度为0.796~0.899,量表信度良好。该量表包含3个因子,累积解释方差变异为68.857%。每个条目的因子载荷值为0.468~0.862,而条目的具体归属则与以往的研究结论有所不同。3个分量表间的相关系数为0.515~0.663,总量表的相关系数为0.731~0.949,说明量表结构、内容效度良好。验证性因素分析量表的理论模型剔除2个条目后标准化残差均方根为0.070,比较拟合指数为0.904。结论工作-生活平衡量表测评护士工作-生活平衡状态具有较好的信度和结构效度,模型拟合度稍差,建议扩大样本量进一步验证。

中青年急性心肌梗死患者重返工作障碍量表编制及信度效度检验

目的:编制中青年急性心肌梗死患者重返工作障碍量表并检验其信度、效度,为评估中青年急性心肌梗死患者重返工作障碍程度提供可靠工具。方法:基于Feuerstein模型,通过文献研究、访谈和德尔菲专家函询法,形成初始量表。采用便利抽样法,选取2022年8月—11月浙江省某综合性医院414例中青年急性心肌梗死患者进行正式调查,筛选条目并检验量表的信度、效度。结果:中青年急性心肌梗死患者重返工作障碍量表包含4个维度,20个条目。探索性因子分析最终提取4个公因子,累计方差贡献率为64.437%。量表各条目内容效度指数为0.80~1.00,平均内容效度指数为0.94。量表总的Cronbach’sα系数、重测信度分别为0.915、0.997。结论:中青年急性心肌梗死患者重返工作障碍量表具有良好的信度、效度,可作为中青年急性心肌梗死患者重返工作障碍程度的评估工具。

FNM method for estimating reliability of existing bridges

Combined with current specifications and stress characteristics of concrete filled steel tubular （CFST） arch bridges, the determination principle of safe-middle-failure threestage mode is given. Accordingly, damage probability and failure probability and the corresponding reliability indices are calculated; a direct relationship between reliability indices and three-stage working status is made. Based on the three-stage working mode, a combined FNM （finite element-neural network- Monte-Carlo simulation） method is put forward to estimate the reliability of existing bridges. According to time-dependent reliability theory, subsequent service time is divided into several stages; minimum samples required by the Monte-Carlo method are generated by random sampling; training samples are calculated by the finite element method, and the training samples are extended by the neural network; failure probability and damage probability are calculated by the Monte-Carlo method. Thus, time dependent reliability indices are obtained, and the working status is judged. A case study is investigated to estimate the reliability of an actual bridge by the FNM method. The bridge is a CFST arch bridge with an 83.6 m span and it has been in operation for 10 years. According to analysis results, in the tenth year, the example bridge is still in safe status. This conclusion is consistent with the facts, which proves the feasibility of the FNM method for estimating the reliability of existing bridges.

护理工作中断量表的汉化及信效度检验

目的 汉化护理工作中断量表并检验其信效度。方法 应用Breslin翻译模型将量表直译、回译和文化调试后形成中文版护理工作中断量表。以便利抽样法选取132名护士对量表进行信效度测试。结果 中文版护理工作中断量表包括2个维度和12个条目。中文版量表的内容效度指数为0.88,条目内容效度指数为0.625~1.000;总量表的Cronbach’s α系数为0.931,人为因素维度Cronbach’s α系数为0.891,环境因素维度Cronbach’s α系数为0.893,折半信度为0.856,重测信度0.910。结论 中文版护理工作中断量表具有良好的信度和效度,可以评估临床护士的护理工作中断。

心内科病房医疗器械供应可靠性管理研究

目的:构建心内科医疗器械供应可靠性管理指标体系,形成可靠性评估策略,提升可靠性管理水平。方法:从医疗器械使用前备件、使用中追踪和使用后处理3个环节,划分13个供应管理事项,在全程管理中开展工作差错概率、质量问题概率和诊疗风险预期评估,形成分级分层、质量规范、部门合作的全过程管理对策。采用随机抽样法选取2021-2022年深圳市龙华区人民医院心内科病房126台医疗器械运行的2000次数据资料,按照器械供应模式不同,分别采用部门协同式管理的协同管理模式(1000次)和可靠性评估管理的评估管理模式(1000次)进行器械供应管理。对比不同管理模式医疗器械供应可靠性和满意度。结果:采用评估管理模式的医疗器械使用前备件、使用中追踪、使用后处理3个环节以及供应全程的工作差错概率分别为(4.74±2.19)%、(4.39±1.85)%、(5.75±1.88)%和(8.29±1.30)%,均低于协同管理模式,其差异有统计学意义(t=5.367、5.663、5.432、6.847,P<0.05),质量问题概率分别为(4.13±1.67)%、(3.89±1.25)%、(5.28±1.84)%和(7.64±1.18)%,均低于协同管理模式,其差异有统计学意义(t=6.504、6.229、5.123、6.166,P<0.05),诊疗风险预期分别为(2.74±0.89)%、(2.47±0.96)%、(3.42±0.95)%和(4.02±1.09)%,均低于协同管理模式,其差异有统计学意义(t=7.027、6.509、8.915、9.266,P<0.05);相关工作人员对采用评估管理模式的医疗器械性能质量、消毒规范、供应及时性、协作水平和使用安全性的满意度分别为(93.54±4.65)%、(91.67±4.11)%、(94.58±4.34)%、(92.39±3.82)%和(90.97±3.76)%,均高于协同管理模式,其差异有统计学意义(t=2.809、3.030、2.843、4.939、3.739,P<0.05)。结论:可靠性管理模式可降低医疗器械供应中的工作差错问题和安全风险,提高供应可靠性,改善供应服务质量。

真空断路器弹簧操动机构分闸弹簧的优化设计方法

操动机构分闸弹簧设计时,为解决分闸弹簧出力特性和负载特性不匹配带来的分闸保持不住、分闸速度过大或过小等问题,提出一种分闸弹簧的优化设计方法。首先计算出分闸过程中的力矩与功,然后根据功能原理计算出各位移点的分闸速度,最后根据分闸速度和能量要求等因素对分闸弹簧进行优化。结果表明,优化后的分闸弹簧可使分闸过程中的出力特性和负载特性合理匹配,保证机构可靠分闸的同时,得到满足要求的分闸速度。通过理论计算和试验验证证明了所提优化方法的可行性,为真空断路器弹簧操动机构的分闸弹簧优化设计提供了有益指导。

偏载工况下ZY29000/45/100D液压支架结构强度分析

基于机械结构可靠性分析理论,介绍了一种液压支架关键部件结构改进设计。具体设计中采用有限元仿真分析方法,根据ZY29000/45/100D液压支架基本结构构建刚柔耦合模型,并以此为基础实施偏载工况下液压支架可靠性分析,并根据分析结果实施液压支架关键部件结构改进设计。另外,将液压支架关键部件结构改进设计应用于工程实践,确认该液压支架关键部件结构改进设计具有较高可行性。

基于供电可靠性的10 kV配电网综合不停电作业技术探讨与实践

基于10 kV配电网不停电作业技术体系,阐述了绝缘杆、绝缘手套作业法等常规带电作业技术以及旁路作业法、“微网”发电作业法等综合不停电作业技术的应用原理及典型场景。针对长时间、大范围停电检修的难题,探讨了综合不停电作业方法的应用。最后,以更换环网柜和线路综合检修为例,制订停、带电一体化实施方案及作业流程,验证了综合不停电作业方法的可行性与有效性,进而为持续提高配网供电可靠性提供了有力支撑。

基于边坡可靠性分析的调水工程河道断面优化研究

研究以调水工程河道断面优化为背景,提出基于边坡可靠性分析的设计方法。通过建立边坡开挖模型,采用随机场理论,分析土体参数变化,确保每一级挖掘后边坡安全系数满足工程设计要求。结果表明,优化后的断面水位更为稳定,水流速度波动范围减小,验证了该方法的有效性。研究有助于确保河道断面在挖掘过程中的稳定性,从而提高工程的可行性,对调水工程领域与河道断面优化设计中具有重要意义。

环境应力筛选与电子部件早期失效模式分析

环境应力筛选是对产品施加规定的温度循环、振动应力,以发现和剔除产品制造过程中的不良零件、元器件和工艺缺陷等早期故障的一种工序。本文以某系列船用断路器控制器为研究对象,分析该系列电子设备进行的环境应力筛选的试验条件,环境应力筛选实验中出现的故障现象,并对故障进行统计,分析了电子部件的早期失效模式。通过后续的可靠性试验,说明经过环境应力筛选的电子设备其工作可靠性得到有效提高。分析与试验结果表明,环境应力筛选可有效剔除电子部件的早期失效和工艺缺陷,提高设备的工作可靠性。

Topology control of tactical wireless sensor networks using energy efficient zone routing

The US Department of Defense （DoD） routinely uses wireless sensor networks （WSNs） for military tactical communications. Sensor node die-out has a significant impact on the topology of a tactical WSN. This is problematic for military applications where situational data is critical to tactical decision making. To increase the amount of time all sensor nodes remain active within the network and to control the network topology tactically, energy efficient routing mechanisms must be employed. In this paper, we aim to provide realistic insights on the practical advantages and disadvantages of using established routing techniques for tactical WSNs. We investigate the following established routing algorithms： direct routing, minimum transmission energy （MTE）, Low Energy Adaptive Cluster Head routing （LEACH）, and zone clustering. Based on the node die out statistics observed with these algorithms and the topological impact the node die outs have on the network, we develop a novel, energy efficient zone clustering algorithm called EZone. Via extensive simulations using MATLAB, we analyze the effectiveness of these algorithms on network performance for single and multiple gateway scenarios and show that the EZone algorithm tactically controls the topology of the network, thereby maintaining significant service area coverage when compared to the other routing algorithms.

IUKF neural network modeling for FOG temperature drift

A novel neural network based on iterated unscented Kalman filter （IUKF） algorithm is established to model and com- pensate for the fiber optic gyro （FOG） bias drift caused by temperature. In the network, FOG temperature and its gradient are set as input and the FOG bias drift is set as the expected output. A 2-5-1 network trained with IUKF algorithm is established. The IUKF algorithm is developed on the basis of the unscented Kalman filter （UKF）. The weight and bias vectors of the hidden layer are set as the state of the UKF and its process and measurement equations are deduced according to the network architecture. To solve the unavoidable estimation deviation of the mean and covariance of the states in the UKF algorithm, iterative computation is introduced into the UKF after the measurement update. While the measure- ment noise R is extended into the state vectors before iteration in order to meet the statistic orthogonality of estimate and mea- surement noise. The IUKF algorithm can provide the optimized estimation for the neural network because of its state expansion and iteration. Temperature rise （-20-20℃） and drop （70-20℃） tests for FOG are carried out in an attemperator. The temperature drift model is built with neural network, and it is trained respectively with BP, UKF and IUKF algorithms. The results prove that the proposed model has higher precision compared with the back- propagation （BP） and UKF network models.

Optimization of Laser Ablation Technology for PDPhSM Matrix Nanocomposite Thin Film by Artificial Neural Networks-particle Swarm Algorithm

A new thermal ring-opening polymerization technique for 1, 1, 3, 3-tetra-ph enyl-1, 3-disilacyclobutane （TPDC） based on the use of metal nanoparticles produced by pulsed laser ablation was investigated. This method facilitates the synthesis of polydiphenysilylenemethyle （PDPhSM） thin film, which is difficult to make by conventional methods because of its insolubility and high melting point. TPDC was first evaporated on silicon substrates and then exposed to metal nanoparticles deposition by pulsed laser ablation prior to heat treatment.The TPDC films with metal nanoparticles were heated in an electric furnace in air atmosphere to induce ring-opening polymerization of TPDC. The film thicknesses before and after polymerization were measured by a stylus profilometer. Since the polymerization process competes with re-evaporation of TPDC during the heating, the thickness ratio of the polymer to the monomer was defined as the polymerization efficiency, which depends greatly on the technology conditions. Therefore, a well trained radial base function neural network model was constructed to approach the complex nonlinear relationship. Moreover, a particle swarm algorithm was firstly introduced to search for an optimum technology directly from RBF neural network model. This ensures that the fabrication of thin film with appropriate properties using pulsed laser ablation requires no in-depth understanding of the entire behavior of the technology conditions.