共查询到19条相似文献,搜索用时 531 毫秒
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简要介绍了可靠性强化试验技术原理与特点,总结了其在平板电视电源模块研发阶段中的应用方法,着重阐述了试验过程和五个类型的试验剖面;引述了激发应力范围的统计学方法,并给出了部分产品应用实施可靠性强化试验技术的典型案例,说明其在激发暴露产品设计、工艺缺陷等方面的突出效果。 相似文献
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高加速寿命应力试验(HALT),是一种通过施加阶梯强化应力于试品,达到快速发现产品潜在缺陷,操作设计边际及结构强度极限的试验方法,主要应用于产品研发设计阶段。由于该方法效果明显,目前已越来越多的电子电气产品制造商认可并推广使用,成为研发设计工程师提高产品可靠性的重要试验手段。本文简要介绍HALT试验的目的,并结合实际,探讨了HALT试验设备的关键性能指标。另外,基于日常实践经验,重点分析和讨论了HALT试验过程中应该关注的一些技术处置措施,从而帮助测试人员正确执行HALT。 相似文献
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本文以标准GB/T 29309-2012为基础,以某款开关电源为例,对HALT试验设备、工作极限与破坏极限、试验步骤及设备运行中注意点等方面展开介绍,为电子产品可靠性测试提供相关探讨。 相似文献
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战术导弹所承受的环境应力是影响其可靠性的主要因素之一。本文论述了综合环境试验在保证战术导弹可靠性中所起的作用,并对综合试验剖面与环境应力的确定,性能监测点及监测周期的确定,夹具的设计等一系列综合环境试验中遇到的问题进行了研讨。 相似文献
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针对轨道交通相关组件、尤其是密封圈进入到次轮四级修所要进行的频繁维护及更换所耗费的大量人力、物力及财力,需要确定密封圈的剩余寿命,为维修及更换提供理论依据。本文首先分析密封圈的工作环境,确定密封圈的使用中主要的敏感的环境应力为温度;随后对密封圈进行HALT试验,根据压缩率确定其极限工作环境温度;最后对密封圈进行四个温度的加速寿命寿命试验,根据密封圈的压缩变形率以及基于温度的寿命评估方程阿伦尼斯方程,预估橡胶密封圈的剩余寿命,确定密封圈的剩余寿命为12 371 h。 相似文献
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本文介绍了超高斯(分布)随机振动HALT技术,对超高斯(分布)随机振动HALT试验剖面的建立提出了方法和建议,主要包括试验顺序的选择、应力强度的确定、步进量级的选择、驻留时间确定和试验停止原则等五方面,并总结了现场试验的要求和注意事项。 相似文献
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文章先说明了电气设备中电源插头LN插脚之间剩余电压和剩余能量的测量是考虑“差模干扰”的影响。而L(N)插脚与保护地之间的剩余电压和剩余能量的测量考虑“共模干扰”的影响。接着介绍了安全电压和安全能量的限值是如何确定的。然后重点分析常见电源电路中的X电容和放电电阻位置对电源插头的剩余电压和剩余能量的影响。并通过具体案例说明插头剩余电压和剩余电量是如何测量的。最后详细对电源插头达到安全电压所需时间的进行了不确定度分析和计算。 相似文献
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Alexander H. Elliott Ton H. Snelder Richard W. Muirhead Ross M. Monaghan Amy L. Whitehead Santiago A. Bermeo-Alvear Carl J. Howarth 《Environmental management》2020,65(2):272-285
A common land and water management task is to determine where and by how much source loadings need to change to meet water quality limits in receiving environments. This paper addresses the problem of quantifying changes in loading when limits are specified in many locations in a large and spatially heterogeneous catchment, accounting for cumulative downstream impacts. Current approaches to this problem tend to use either scenario analysis or optimization, which suffer from difficulties of generating scenarios that meet the limits, or high complexity of optimization approaches. In contrast, we present a novel method in which simple catchment models, load limits, upstream/downstream spatial relationships and spatial allocation rules are combined to arrive at source load changes. The process iteratively establishes the critical location (river segment or lake) where the limits are most constraining, and then adjusts sources upstream of the critical location to meet the limit at that location. The method is demonstrated with application to New Zealand (268,000 km2) for nutrients and the microbial indicator E. coli, which was conducted to support policy development regarding water quality limits. The model provided useful insights, such as a source load excess (the need for source load reduction) even after mitigation measures are introduced in order to comply with E. coli limits. On the other hand, there was headroom (ability to increase source loading) for nutrients. The method enables assessment of the necessary source load reductions to achieve water quality limits over broad areas such as large catchments or whole regions. 相似文献
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本文简要介绍了可靠性强化试验技术原理与特点,总结了可靠性强化试验技术在家电产品研发阶段中的应用方法,详细阐述了可靠性强化试验过程和试验剖面特点;给出了部分产品实施可靠性强化试验的结果与实施经验,论述了如何在家电产品中经济高效地实施可靠性强化试验技术. 相似文献
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X. B. Feng 《International Journal of Green Energy》2016,13(14):1451-1459
This study experimentally investigates lean methane/air premixed combustion in a catalytic zirconia foam burner. The burner is packed with an inert perforated alumina plate at the inlet preheating zone and with catalytic zirconia foams at the combustion zone. Catalytic foams are prepared by using a modified perovskite catalyst (LaMn0.4Co0.6O3), in which the transition metal ion Co is partially substituted by Mn and supported by inert zirconia foam. Results indicate that the flame stability limits of both catalytic and inert burners expand with increasing equivalence ratios. The stable combustion region of the catalytic burner is larger than that of the inert burner. The heterogeneous catalytic combustion effect can decrease and increase the lower and upper flame stability limits, respectively. The central temperatures of the flame fronts are higher in the catalytic burner than in the inert burner. The pressure drops of the catalytic burner are almost equal to those of the inert burner in cold flows but are significantly higher than those in the inert burner in reaction flows. Less amounts of carbon monoxide, nitric oxides, and unburned hydrocarbon emissions are detected in the catalytic burner relative to the inert burner. The thermal radiation efficiencies of the catalytic burner vary between 0.24 and 0.39 and are favorably superior to those of the inert burner, ranging from 0.11 to 0.20. 相似文献
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为进一步完善我国废物焚烧标准体系,防控废物焚烧环境风险,本文对欧盟废物焚烧指令与我国焚烧标准体系进行了对比分析。欧盟废物焚烧指令分别对专用焚烧厂和协同焚烧厂从废物运输到处理处置全过程的污染物排放控制做出了相关规定,适用于危险废物和非危险废物的焚烧以及常规污染物和有毒污染物的控制。欧盟废物焚烧指令对不同规模的焚烧设施采用统一标准,以日均值和半小时均值为污染物排放限值,更客观、准确地评价了污染物排放对环境的影响。与欧盟废物焚烧指令相比,我国废物焚烧标准涉及废物联合利用处置的相关条文较少,内容不详,项目缺失。我国烟尘、HCl的排放限值均在欧盟标准限值6倍以上,SO2的排放限值是欧盟标准的4~8倍。除CO、NOx的排放限值外,其他污染物排放限值也明显高于欧盟标准限值。我国采用抽样监测方法,监测结果可能在日常排放值的95%置信区间外,不具备代表性。我国可借鉴欧盟废物焚烧指令的成果制定协同焚烧标准,并严格污染物排放限值,考虑采用日均值或半小时均值的评价方法,提高我国废物焚烧标准的精确性和可执行性。 相似文献
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Using data from a study conducted in the Cranberry Wilderness Area of West Virginia, United States, this paper describes how
a modified importance—performance approach can be used to prioritize wilderness indicators and determine how much change from
the pristine is acceptable. The approach uses two key types of information: (1) indicator importance, or visitor opinion as
to which wilderness indicators have the greatest influence on their experience, and (2) management performance, or the extent
to which actual indicator conditions exceed or are within visitor expectations. Performance was represented by calculating
indicator performance estimates (IPEs), as defined by standardized differences between actual conditions and visitor preferences
for each indicator. The results for each indicator are then presented graphically on a four-quadrant matrix for objective
interpretation. Each quadrant represents a management response: keep up the good work, concentrate here, low priority, or
possible overkill. The technique allows managers to more systematically and effectively utilize information routinely collected
during the limits of acceptable change wilderness planning process.
This paper is submitted with the approval of the Director of the West Virginia Agricultural and Forestry Experiment Station
as Scientific Article No. 541. The study was funded in part, through a grant from the USDA Forest Service, Monongahela National
Forest. 相似文献
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Effect of the effective stress coefficient and sorption-induced strain on the evolution of coal permeability: Experimental observations 总被引:2,自引:0,他引:2
Zhongwei Chen Zhejun Pan Jishan Liu Luke D. Connell Derek Elsworth 《International Journal of Greenhouse Gas Control》2011,5(5):1284-1293
Permeability is one of the most important parameters for CO2 injection in coal to enhance coalbed methane recovery. Laboratory characterization of coal permeability provides useful information for in situ permeability behavior of coal seams when adsorbing gases such as CO2 are injected. In this study, a series of experiments have been conducted for coal samples using both non-adsorbing and adsorbing gases at various confining stresses and pore pressures. Our observations have showed that even under controlled stress conditions, coal permeability decreases with respect to pore pressure during the injection of adsorbing gases. In order to find out the causes of permeability decrease for adsorbing gases, a non-adsorbing gas (helium) is used to determine the effective stress coefficient. In these experiments using helium, the impact of gas sorption can be neglected and any permeability reduction is considered as due to the variation in the effective stress, which is controlled by the effective stress coefficient. The results show that the effective stress coefficient is pore pressure dependent and less than unity for the coal samples studied. The permeability reduction from helium experiments is then used to calibrate the subsequent flow-through experiments using adsorbing gases, CH4 and CO2. Through this calibration, the sole effect of sorption-induced strain on permeability change is obtained for these adsorbing gas flow-through experiments. In this paper, experimental results and analyses are reported including how the impact of effective stress coefficient is separated from that of the sorption-induced strain on the evolution of coal permeability. 相似文献