共查询到20条相似文献,搜索用时 171 毫秒
1.
简述电路板组件随机振动试验仿真实现的原理和方法。通过有限元软件对电路板组件模型进行随机振动仿真分析,结合电路板组件随机振动试验的频率响应特性结果验证了仿真分析的有效性。 相似文献
2.
本文分析对系统基准点定加速度自功率谱密度随机振动试验,由于基准点阻抗不等效而产生过试验,控制力功率谱密度,模拟阻抗等效,可避免系统随机振动试验的过试验,使其系统随机振动试验接近实际. 相似文献
3.
美国格鲁门公司于1980年提出了磁带随机振动试验方法。采用这种方法,凡有电动振动设备,只需添置一台盒式磁带机,即可代替昂贵的随机振动程控设备,进行随机振动试验。 作者就从英国引进的随机数控分析设备DVC500及振动台系统,对该方法作一扼要介绍。文章涉及试验原理、实施方案、应用实例以及经验和体会。 相似文献
4.
本文介绍了随机振动试验的概念及提高产品可靠性的机理,通过分析提出了选择随机振动参数的三项原则。结合军用车载电电源可靠性试验,从参数确定、试验夹具设计、试验实施三个方面,论述开展随机振动试验的方法及步骤,为正确实施随机振动试验及试验过程质量监督提供了参考。 相似文献
5.
6.
随机振动试验是高效应力筛选中的二个重要试验之一。本文介绍用扫描随机振动试验来进行筛选的方法,根据有关资料和初步实践定出激振标准,并对产品的电路板做了试验。 相似文献
8.
9.
近年来,随机振动技术被广泛地应用于产品的可靠性试验、质量考核试验及结构分析试验等方面。本文介绍了利用微型机在液压振动台系统上实现随机振动控制的技术方法和实例。 相似文献
10.
11.
12.
13.
14.
CAWS600自动气象站工作作业维护程序探讨 总被引:3,自引:0,他引:3
自动气象站是北京自然环境试验站中的一个工作项目。本文阐述了该.工作的职责和重要性及设备作业维护要求。分析了自动站发展过程中的问题,讨论了一下发展方向,需要实现资源共享和提高自动站的效益。 相似文献
15.
Bing Du Xiaoyi Ji R. Daren Harmel Larry M. Hauck 《Journal of the American Water Resources Association》2009,45(2):475-484
Abstract: The Soil and Water Assessment Tool (SWAT) model was evaluated for estimation of continuous daily flow based on limited flow measurements in the Upper Oyster Creek (UOC) watershed. SWAT was calibrated against limited measured flow data and then validated. The Nash‐Sutcliffe model Efficiency (NSE) and mean relative error values of daily flow estimations were 0.66 and 15% for calibration, and 0.56 and 4% for validation, respectively. Also, further evaluation of the model’s estimation of flow at multiple locations was conducted with parametric paired t‐test and nonparametric sign test at a 95% confidence level. Among the five main stem stations, four stations were statistically shown to have good agreement between predicted and measured flows. SWAT underestimated the flow of the fifth main stem station possibly because of the existence of complex flood control measures near to the station. SWAT estimated the daily flow at one tributary station well, but with relatively large errors for the other two tributaries. The spatial pattern of predicted flows matched the measured ones well. Overall, it was concluded from the graphical comparisons and statistical analyses of the model results that SWAT was capable of reproducing continuous daily flows based on limited flow data as is the case in the UOC watershed. 相似文献
16.
17.
基于哈萨克斯坦阿拉木图站和新疆乌鲁木齐站、伊宁站的1967-2009年1月份的降水资料,利用一元线性回归法、Mann-Kendall突变检验和Morlet小波分析的方法,分析了该区域降水的变化特征,结果表明:阿拉木图和伊宁1月份降水变化不明显,呈微弱的下降趋势;乌鲁木齐降水呈显著增加趋势。阿拉木图降水年代际变化不明显,乌鲁木齐于20世纪80年代以前降水偏少,此后降水逐渐增多,伊宁和乌鲁木齐年代际变化相似。阿拉木图1月份降水没有发生突变,在1980年以前存在6—7年的短周期变化,此后存在10—15年的长周期变化。伊宁1月份降水没有发生突变,1980年以前存在6年的短周期变化,此后存在8年和11年的周期变化,变化周期不稳定。乌鲁木齐于1978、1981发生了突变,存在6年左右和12年周期变化。 相似文献
18.
针对干旱生态敏感区水电站环境影响后评价的要求,设计备选指标集,采用频次分析法进行指标初选,采用专家咨询法进行指标精选,建立由4项二级指标、14项三级指标构成的干旱生态敏感区水电站环境影响后评价指标体系,采用层次分析法给每个指标赋予权重.将该评价指标体系用于某水电站建设的实例分析,结果表明,水电站运行以来总体上有利影响大... 相似文献
19.
根据卧龙河气田增压南站周边环境状况、增压机噪声强度及频谱分析特性,结合吸音、隔音、扩容、变频、减震、阻尼等降噪原理和治理技术,提出了卧龙河增压南站噪声最优化的治理方案,即七台机组噪声综合治理方案。该方案可满足厂界噪声达到GB12348-90规定的三类标准要求,一次性投资费用为303万元,且便于压缩机日常维护及保养,并可进行机组就地大修。 相似文献
20.
David C. Froehlich 《Journal of the American Water Resources Association》1994,30(6):1055-1062
ABSTRACT: Design of a stormwater pump station is a complicated procedure because of the large number of parameters that are involved. Even the most basic pump station serving a small catchment requires a computationally intensive iterative evaluation. However, the design problem consists primarily of finding the combination of temporary storage and pump capacity that accommodates runoff of the selected recurrence interval for the least cost. A procedure is developed for rapidly obtaining the needed relation between storage volume and discharge for small pump stations where a constant outflow can be assumed and the inflow hydro-graph can be represented using the modified rational method with rainfall given by a widely-used intensity-duration equation. Accepting the limitations of the modified rational method and the simplifications applied to pump station operation, the procedure provides an uncomplicated way of rapidly finding the stormwater runoff volume that needs to be temporarily stored for given values of pump discharge and activation water level (or, equivalently, activation storage volume). Ultimate determination of temporary runoff storage will depend on an economic analysis of the trade-off between storage volume and pump capacity. 相似文献