大型多功能综合环境试验系统介绍

由中国电子产品可靠性民环境试验研究所自行设计、研制、开发的大型多功能综合环境试验系统，是目前国内试验容积最大、功能最全、结构最复杂、九十年代国际先进的三综合环境应力试验系统。其性能指标先进，各项配置经济，合理，特别是具有综合环境条件下雷达信号／发射目标跟踪试验能力，这在国内尚属首创，在国际也未有前列。     

综合环境应力试验初探

综合环境应力试验是产品可靠性研究的重要手段，本文主要介绍了综合环境应力试验的一系列特点及几种典型的试验。     

综合环境应力可靠性试验设备技术指标及选型的有关问题探讨

综合环境应力可靠性试验对于提高电子设备的可靠性有着十分重要的作用，综合环境应力可靠性试验设备是实施上述试验的主要技术手段，如何确定和选择综合环境应力可靠性试验设备的技术指标是关系到试验设备能否完成试验任务的关键。本文就综合环境应力可靠性试验设备的有关技术指标的论证和确定依据进行阐述和探讨，以期引起试验同行的关注。     

常规兵器三综合环境试验技术研究

对温度-湿度-振动综合试验过程中的环境应力故障分析、试验标准剪裁、试验量值确定、试验设备及试验过程、试验结果评定等问题进行分析论述，分析结果对温度-湿度-振动综合试验设备选型和温度-湿度-振动综合试验具有参考价值。     

战术导弹综合环境试验中遇到的若干问题研讨

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。     

涂装工艺综合/组合环境加速试验研究及应用

本文阐述了实验室综合/组合加速试验的意义和作用,分析了涂装工艺综合/组合加速模拟试验设计的基本要求和方法,选取了6种典型涂装工艺试验样品,开展了实验室单因素试验、多因素综合/组合加速环境试验和自然大气暴露试验的对比研究,结果表明综合/组合加速环境试验具有较好的相关性和加速性。     

综合环境试验系统中受试产品表面Cl元素沉降聚积效果正交分析

针对综合环境试验系统中受试产品表面检出Cl元素的异常现象,提出基于正交试验的受试产品表面Cl元素沉降聚积效果分析方法。介绍试验系统工作原理与Cl元素检测方法,明确试验目标,通过前期实验筛除试验系统中与Cl元素沉降聚积无关的因素,最终确定三因素两水平的正交试验,对通风、吸波材料、试验时间等进行组合研究。通过对正交试验结果分析,发现了导致Cl元素沉降聚积量最大的多因素组合,从而为大量开展的综合环境试验中Cl元素的控制提供参考。     

某机载雷达微波组件综合环境应力筛选方法研究

以某机载雷达的综合环境应力筛选为研究对象,把GJB 1032传统的环境应力筛选方案和可靠性鉴定试验应力剖面结合,提出了综合环境应力筛选方法。通过研究综合环境应力筛选方法,形成一套有效的综合环境应力筛选方案,对组件进行综合环境应力筛选,进而进行故障统计分析,验证了该方法的有效性。     

H3880-V890B综合环境应力可靠性试验系统介绍

综合环境应力可靠性试验,对于验证产品可靠性平均无故障工作时间（ＭＴＢＦ）和暴露产品设计、元件选用２、生产工艺等方面的缺陷有着十分重要的作用。综合环境应力可靠性试验设备是实施该项试验的重要手段。本文详述Ｈ３８８０－Ｖ８９０Ｂ试验系统的布局、功能、参数及主要技术,旨城向试验同行介绍目前试验设备的最新技术动态。同时希望资源共享,为暂不具备大型综合环境应力设备的单位提供协作,共同为提高我国的装备技术水平作     

对雷达模拟环境试验的思考

雷达环境试验是产品特定技术要求规定的。只有科学的试验方法，才能有效评价雷达在我国自然环境条件下贮存、运输和使用的适应性。自然环境是一个多变量的综合环境，如：温度、阳光、生物、风沙、雨水和机械环境应力等同时对产品作用。而雷达环境试验是用模拟的方法，在试...     

大气污染物最大落地浓度计算方法的比较

大气环境影响评价工作中，采用有风点源扩散模式定量预测大气污染物的最大落地浓度，通常有轴线法、常数法和非常数法这三种计算方法。本文通过实例对上述三种计算方法进行比较分析，明确了各自的适用范围，其中以轴线法的应用最为全面。     

MANAGING CRISIS: THE EFFECTIVENESS OF LOCAL DISTRICTS FOR CONTROL OF GROUND WATER MINING1

: This article examines the willingness and capacity of local districts to control ground water mining of the Ogallala Aquifer in the High Plains. The questions of willingness and capacity were approached through extensive field interviews and a survey of all district board members and managers. The analysis focuses on the policy alternatives board members and managers perceive and how they evaluate these alternatives. Methodologically, the study utilized factor analysis of responses rating the desirability of various policy alternatives to ascertain what alternatives were perceived by the sample. Then the sample's preferences for each of the identified factors were calculated. The results demonstrate that the sample of those who must regulate if ground water mining is to be controlled at the substate level are not oriented to regulatory policies and therefore lack the willingness to deal with ground water mining.     

IRRIGATION METHODS AND TRANSPORT OF IMAZAMETHABENZ‐METHYL TO GROUND WATER: GREENFIELDS BENCH,MONTANA1

ABSTRACT: A series of gravel terraces support a shallow aquifer that is the sole source of drinking water for three public water supplies and more than 400 private wells on the Greenfields Bench in west‐central Montana. Farming practices on the Greenfields Bench include irrigation of malting barley and the yearly application of herbicides for the control of weeds. The most commonly used herbicide (imazamethabenz‐methyl, U.S. trade name Assert®) has been found in the ground water on the Greenfields Bench. An experiment was conducted in 2000 and 2001 to characterize the transport of Assert and its acid metabolite to ground water under three irrigation methods: flood, wheel line sprinkler, and center pivot sprinkler. Results show that Assert concentrations in ground water are controlled by hydraulic loading rates of each irrigation method, Assert persistence in soil, hydraulic characteristics of the aquifer, and adsorption/desorption of Assert onto clay particles and organic matter.     

THE ECONOMIC VALUE OF GROUND WATER RECHARGE FOR IRRIGATION USE1

ABSTRACT: Artificial recharge as a means of augmenting water sup plies for irrigation is a management alternative which policy makers in ground water decline areas are beginning to consider seriously. A conceptual model is developed to evaluate the economic benefits from ground water recharge under conditions where the major water use is irrigation. The methodology presented separates recharge benefits into two components: pumping cost savings and aquifer extension benefits. This model is then applied to a Nebraska case to approximate the value of recharge benefits as a function of aquifer response. discount rate, and commodity prices. It was found that recharge benefits vary from less than $2 to over $6 an acre foot recharged.     

EFFECT OF SEMI‐PERCHED GROUND WATER ON MONITORING OF GROUND WATER LEVELS IN A DEVELOPED AQUIFER1

ABSTRACT: Interpretation of ground water level changes in a developed aquifer usually relies on reference to some benchmark such as “predevelopment” ground water levels, changes from fall to fall and/or spring to spring, or to determination of maximum stress during the pumping season. The assumption is that ground water levels measured in the monitoring well accurately reflect the state of the ground water resource in terms of quantity in storage and the effects of local pumping. This assumption is questionable based on the patterns shown in continuous hydrographs of water levels in monitoring wells in Nebraska, and wells installed to determine vertical gradients. These hydrographs show clear evidence for vertical ground water gradients and recharge from overlying parts of the aquifer system to deeper zones in which production wells are screened. The classical concept of semi‐perched ground water, as described by Meinzer, is demonstrated by these hydrographs. The presence of semi‐perched ground water (Meinzer definition, there is no intervening unsaturated zone) invalidates the use of measured ground water levels in regional observation programs for detailed numerical management of the resource. Failure to recognize the Meinzer effect has led to faulty management. The best use of data from the observation well network would be for detection of trends and education unless it is clearly understood what is being measured.     

Optimal Location and Management of Waste Disposal Facilities Affecting Ground Water Quality1

ABSTRACT: Numerical simulation of ground water solute transport is combined with linear programming to optimize waste disposal. A discretized form of the equation governing solute transport is included as a set of constraints in a linear program. Two problems are described. First, the management model is used to maximize ground water waste disposal. The model constrains disposal activities so that the quality of local ground water supplies is protected. Parametric programming is shown to be important in evaluating waste disposal tradeoffs at the various facilities. Changes in the velocity field induced by waste water injection cause a nonlinearity in the solute transport equation which is dealt with by employing an iterative procedure. The second problem is aimed at identifying all sites which are suitable for waste disposal in the subsurface. The management model is manipulated so that the optimal value of the dual variables are “unit source impact indicators.” This physical interpretation is valuable in identifying feasible disposal sites. The joint simulation and optimization approach permits the management of complex ground water systems where the aquifer is used simultaneously for waste disposal and water supply.     

Occurrence of Volatile Organic Compounds in Aquifers of the United States1

Abstract: Samples of ambient ground water were collected during 1985‐2002 from 3,498 wells in 98 aquifer studies throughout the United States. None of the sampled wells were selected because of prior knowledge of nearby contamination. Most of these samples were analyzed for 55 volatile organic compounds (VOCs) to characterize their national occurrence. Volatile organic compounds were found in samples collected from 90 of the 98 aquifer studies. Occurrence frequencies of one or more VOCs for the 98 aquifer studies ranged from 0 to about 77% at an assessment level of 0.2 microgram per liter (μg/l). The aquifer studies with the largest occurrence frequencies were in southern Florida, southern New York, southern California, New Jersey, and Nevada. Trihalomethanes and solvents were the most frequently occurring VOC groups. Of the 55 VOCs included in this assessment, 42 occurred in at least one sample at an assessment level of 0.2 μg/l. Chloroform, perchloroethene, and methyl tert‐butyl ether were the most frequently occurring VOCs. Many factors, such as the hydrogeology of the aquifer, use of VOCs, land use, and the transport and fate properties of VOCs, affect the occurrence of VOCs in ground water.     

STABLE ISOTOPE CHARACTERIZATION OF THE IMPACTS OF ARTIFICIAL GROUND WATER RECHARGE1

ABSTRACT: Stable isotopes of deuterium and oxygen-18 of surface and ground water, together with anion concentrations and hydraulic gradients, were used to interpret mixing and flow in ground water impacted by artificial recharge. The surface water fraction (SWF), the percentage of surface water in the aquifer impacted via recharge, was estimated at different locations and depths using measured deuterium/hydrogen (DIH) ratios during the 1992, 1993, and 1994 recharge seasons. Recharged surface water completely displaced the ground water beneath the recharge basins from the regional water table at 7.60 m to 12.16 m below the land surface. Mixing occurred beneath the recharge structures in the lower portions of the aquifer (>12.16 m). Approximately 12 m down-gradient from the recharge basin, the deeper zone (19.15 m depth) of the primary aquifer was displaced completely by recharged surface water within 193, 45, and 55 days in 1992, 1993, and 1994, respectively. At the end of the third recharge season, recharged surface water represented ～50 percent of the water in the deeper zone of the primary aquifer ～1000 m downgradient from the recharge basin. A classic asymmetrical distribution of recharged surface water resulted from the recharge induced horizontal and vertical hydraulic gradients. The distribution and breakthrough times of recharged surface water obtained with stable isotopes concurred with those of major anions and bromide in a tracer test conducted during the 1995 recharge season. This stable isotope procedure effectively quantified mixing between surface and ground water.     

成都市某区暴雨径流过程模拟分析

为提高城市雨洪管理的效率,最大限度地减少暴雨洪水带来的危害,针对城市防洪排涝的需要,在分析成都市某区降雨径流规律后,建立了该区暴雨径流模拟的数学模型,有助于采取相应措施充分利用雨洪资源。通过对雨洪过程模拟验证表明,模型适合该区域的实际情况,具有一定的合理性和可靠性。     

RAPID WATER TABLE RISE1

ABSTRACT: There are unpublished reports of rapid and large rises in the water table which are out of proportion to the infiltrated volumes of water. The phenomenon seems to result from the conversion of a tension saturated zone to phreatic water by one of several mechanisms. The effect could be triggered when the tension saturated zone intersects: the ground surface, a saturated soil horizon, or a coarse zone. The phenomenon could prove to be a common link in explaining several seemingly diverse phenomena which characterize non-Hortonian runoff in a humid environment. Under certain conditions storm peaks are dominated by flow from small, restricted, “variable source” areas that contributed runoff when saturated from below by rising water tables; for other streams, ground water input forms the major part of the flood peak. The explanation for these observations could lie in an understanding of the rapid water table rise phenomenon. Such a mechanism. if widespread, would provide the means for producing saturation at or near the surface shortly after rainfall commences. The phenomenon should be documented and closely analyzed from a number of perspectives to define its true role in the hydrology of humid environments.