振动试验及其相关参数的分析

介绍了产品进行振动试验的必要性,对随机振动试验和正弦振动试验分别进行了描述。对随机振动试验中的倍频程、斜率、加速度总均方根值进行了介绍,对正弦振动中的扫频速率、倍频程数、应力循环数、扫频时间的计算公式进行了推导,并通过一个具体的正弦扫频算例,对相关振动参数进行了计算。     

浅析大气环境与健康、疾病的关系

文章对造成大气污染的主要途径,如自然污染、人类活动以及气象条件对大气污染的影响进行了探讨,分析了能源使用、工农业生产过程、交通运输对大气的影响,浅析了大气污染与人类健康、人类疾病的关系,大气污染对呼吸系统、免疫系统,以及对细胞染色体和基因损伤方面的影响。     

我国居民消费对环境的影响

现阶段,我国居民经济能力提高,出现了浪费型消费与攀比型消费,加上日益增长的人口数量,形成了一个巨大的"吞噬环境圈"。为了研究消费对环境的影响,本文立足于消费对碳排放量的影响,构建了STIRPAT模型,分析了人口数、城市化率、人均消费量、碳排放强度对碳排放总量的影响;得出了城市化率对碳排放量具有明显增加作用的结论;计算了人口数、城市化率、人均消费量的增长对碳排放增长量的贡献率,得出了人口数和人均消费量的变化对碳排放量的变化也有显著影响的结论;描述了我国五类消费品的增长情况;提出了消费方式从个人到企业,再到政府,最后到世界的转变过程与转变消费方式的路径,包括建立绿色GDP核算体系、进行绿色城市化、继续降低碳排放强度、加强教育和宣传以改变现存消费观、利用行政和法律实现节能低碳消费方式、重视新型能源技术的开发、拓展利用资源的广度和深度、加强国际交流与合作;最后,总结了改变物质主义价值取向和行为规范,完善绿色产品及基础设施的供给需要注意的三个方面。     

高原气候环境对装备影响及适应性措施

高原地区因地势高而使其自然气候极为特殊复杂,骤变的气候环境易使装备出现“水土不服”的现象,因此高原环境对装备环境适应性提出了更高要求。本文根据高原气候特点以及装备结构组成,从机械系统、动力系统、光学系统、液压系统、电子系统、调温系统、供水系统和装备材料等方面,对高原气候对装备的影响情况进行了分析,有针对性地提出了装备高原环境适应性解决措施,此基础上对加强装备环境适应性提出了建议。     

阳离子PAM的合成及絮凝性能研究

文章叙述了通过利用曼尼兹反应条件的控制,对聚丙烯酰胺进行了阳离子改性,合成胺甲基聚丙烯酰胺。探讨了原料配比、甲醛用量、反应时间、反应温度和二甲胺滴加时间等对胺化率的影响,并对其絮凝性能进行了考察。     

白色污染对农业生态环境安全影响研究

从白色污染产生的方式和途径,白色污染对土壤、农作物的生长、农业机械作业、生态景观以及白色污染本身的化学污染等方面阐述了白色污染对农业生态环境的危害,并对防治白色污染提出了对策和措施。     

基于马尔可夫模型的降水预测及其利用

在介绍马尔可夫链的预测方法与模型的基础上,以山东省文登市为例,根据1953—2005年的降水量资料,对年降水量进行了状态分级;应用马尔可夫模型对该地区的降水情况进行了预测和分析,提出了对雨水资源利用的看法。结果表明,该方法客观、准确、可靠、简便,为区域降水的中短期预测提供了新的解决途径。     

含氮杂环化合物的生物降解研究进展

杂环化合物是焦化、印染、农药等工业废水中常见的有机污染物,是造成这类废水难生物降解的主要原因。本文介绍了国内外对含氮杂环化合物在好氧、厌氧、缺氧条件下以及共基质条件下生物降解性能的研究进展,总结了部分菌种对杂环化合物的降解途径,并对一些现象从分子结构和电荷特性等方面给予了解释。最后对含氮杂环化合物的生物降解提出了进一步的研究方向。     

西北地区水资源态势及可持续发展途径分析

对我国西北地区水资源的现状进行了概述,阐述了在水资源利用中存在的各种问题,如水土流失严重、河道断流、水质污染严重、农用灌溉水大量浪费,等等.并从自然、人为两方面因素进行了原因分析.在此基础上,对西北地区水资源的可持续发展途径进行了探讨.     

大力发展环境科技促进"十一五"任务完成

《国家环境保护"十一五"规划》的颁布,为完成"十一五"环保任务,提供了重要依据。《规划》对环境科技工作提出了新的要求,对"十一五"环境科技工作进行了系统、科学规划。《规划》强调了科技创新、调整经济结构、发展环保产业等方面对完成"十一五"环保任务的重要性。     

协议出让国有土地使用权最低价的确定方法

合理确定协议出让国有土地使用权的最低价,是促进经济与社会发展,防止土地资产流失的重要措施．本文以国家土地管理局的有关现定为依据,在阐述基准地价内涵、基准地价与国有土地使用权出让价相互关系的基础上,探讨了协议出让国有土地使用权最低价的具体确定方法,并将它初步应用在山西省祁县城区土地使用权协议出让最低限价的确定中．     

How to evaluate raw material supply risks—an overview

Some strategic raw materials do have an extremely unsecure supply situation. Several working groups around the world have made criticality assessments for metallic raw materials to analyze the driving impact factors for this instability. However, the influences on raw material availability are manifold and therefore criticality assessment methods are very heterogeneous. Here we give an overview about the differences and similarities of supply risk evaluation in 15 criticality assessment methods. We take the example of Indium, which has been rated in 60% of these criticality studies, and show which data base is used for supply risk evaluation. Our results show a lack of consensus about which indicators give reliable information for raw material supply risk and how these indicators should be aggregated. We anticipate our essay to be a starting point for more justified indicator selection and weighting in criticality assessments.     

手机基站电磁辐射问题释疑

本文就社会普遍关心的手机基站电磁辐射对人体健康的影响问题,从基站电磁辐射属性,强度,对人体健康的影响等,作了较为详细的论述。     

公众对手机基站电磁辐射投诉典型问题及解答

随着中国的移动通信网络进入3G时代,手机基站建设掀起了新一轮高潮.手机基站是手机用户之间信息传递的枢纽,而信息传输的承载方式就是电磁波,也就是通常所称的"电磁辐射".由于绝大多数公众对电磁辐射并不了解,因此"谈辐色变",对手机基站的电磁辐射投诉量逐年增加,一定程度上影响了社区和谐与移动通信业的顺利推进.本文将比较有代表...     

Use of Streamflow Data to Estimate Base Flow/Ground‐Water Recharge For Wisconsin1

Abstract: The average annual base flow/recharge was determined for streamflow‐gaging stations throughout Wisconsin by base‐flow separation. A map of the State was prepared that shows the average annual base flow for the period 1970‐99 for watersheds at 118 gaging stations. Trend analysis was performed on 22 of the 118 streamflow‐gaging stations that had long‐term records, unregulated flow, and provided aerial coverage of the State. The analysis found that a statistically significant increasing trend was occurring for watersheds where the primary land use was agriculture. Most gaging stations where the land cover was forest had no significant trend. A method to estimate the average annual base flow at ungaged sites was developed by multiple‐regression analysis using basin characteristics. The equation with the lowest standard error of estimate, 9.5%, has drainage area, soil infiltration and base flow factor as independent variables. To determine the average annual base flow for smaller watersheds, estimates were made at low‐flow partial‐record stations in 3 of the 12 major river basins in Wisconsin. Regression equations were developed for each of the three major river basins using basin characteristics. Drainage area, soil infiltration, basin storage and base‐flow factor were the independent variables in the regression equations with the lowest standard error of estimate. The standard error of estimate ranged from 17% to 52% for the three river basins.     

Fate and movement of microorganisms in the environment

Summary This literature review indicates how little is known about the growth of introduced bacteria. The available data base is so sparse that one can only speculate on the environmental conditions and the physiological traits that are needed to permit bacterial growth. Although methods are available to label organisms so that their multiplication can be detected under natural conditions, those methods have not been used sufficiently often to provide a meaningful base of information to allow a definition of conditions that favor multiplication of particular species or the organisms that are likely to proliferate in particular environments. However, because methods exist to monitor microbial growth, and new and better methods can be developed easily, it should not be difficult—provided research funds are made available—to expand greatly the data base and provide adequate information to be used for predicting the behavior of genetically engineered organisms in nature.     

LAW,HYDROLOGY, AND SURFACE-WATER SUPPLY IN THE UPPER COLORADO RIVER BASIN1

ABSTRACT: Law and hydrology are inextricably woven together in the pattern of water resource development in the west. The former attempts to allocate a limited and valuable resource as the latter tries to define the limits of the resource. In the past an inadequate data base has made hydrologic estimates difficult and political factors have pushed the law into possibly conflicting commitments in the Colorado River Basin. Through the use of tree-ring research, hydrologists have produced a more definitive data base and placed water allocations such as the Colorado River Compact of 1922 in a clearer long-term perspective. This data base leads to the conclusion that the surface-water supply is about 13.5 million acre-feet per year. This hydrologic limit must be apportioned within an existing legal framework - the “Law of the River.” As development approaches the resource limit in the Upper Colorado River Basin, lawyers and hydrologists must act in concert toward the equitable solution of allocation and reallocation problems.     

EFFECTS OF CLIMATE CHANGE ON HYDROLOGY AND WATER RESOURCES IN THE COLUMBIA RIVER BASIN1

ABSTRACT: As part of the National Assessment of Climate Change, the implications of future climate predictions derived from four global climate models (GCMs) were used to evaluate possible future changes to Pacific Northwest climate, the surface water response of the Columbia River basin, and the ability of the Columbia River reservoir system to meet regional water resources objectives. Two representative GCM simulations from the Hadley Centre (HC) and Max Planck Institute (MPI) were selected from a group of GCM simulations made available via the National Assessment for climate change. From these simulations, quasi-stationary, decadal mean temperature and precipitation changes were used to perturb historical records of precipitation and temperature data to create inferred conditions for 2025, 2045, and 2095. These perturbed records, which represent future climate in the experiments, were used to drive a macro-scale hydrology model of the Columbia River at 1/8 degree resolution. The altered streamflows simulated for each scenario were, in turn, used to drive a reservoir model, from which the ability of the system to meet water resources objectives was determined relative to a simulated hydrologic base case (current climate). Although the two GCM simulations showed somewhat different seasonal patterns for temperature change, in general the simulations show reasonably consistent basin average increases in temperature of about 1.8–2.1°C for 2025, and about 2.3–2.9°C for 2045. The HC simulations predict an annual average temperature increase of about 4.5°C for 2095. Changes in basin averaged winter precipitation range from -1 percent to + 20 percent for the HC and MPI scenarios, and summer precipitation is also variously affected. These changes in climate result in significant increases in winter runoff volumes due to increased winter precipitation and warmer winter temperatures, with resulting reductions in snowpack. Average March 1 basin average snow water equivalents are 75 to 85 percent of the base case for 2025, and 55 to 65 percent of the base case by 2045. By 2045 the reduced snowpack and earlier snow melt, coupled with higher evapotranspiration in early summer, would lead to earlier spring peak flows and reduced runoff volumes from April-September ranging from about 75 percent to 90 percent of the base case. Annual runoff volumes range from 85 percent to 110 percent of the base case in the simulations for 2045. These changes in streamflow create increased competition for water during the spring, summer, and early fall between non-firm energy production, irrigation, instream flow, and recreation. Flood control effectiveness is moderately reduced for most of the scenarios examined, and desirable navigation conditions on the Snake are generally enhanced or unchanged. Current levels of winter-dominated firm energy production are only significantly impacted for the MPI 2045 simulations.     

QUALITY OF 1995 SPRING TOTAL DISSOLVED GAS DATA: COLUMBIA AND SNAKE RWERS1

ABSTRACT: The quality of the U.S. Army Corps of Engineers' (Corps) total dissolved gas (TDG) data base for the 1995 spring spill season was reviewed to determine the value of this information in real-time management decisions regarding river operations. We concluded that problems in transmitting, archiving, correcting and interpreting the records constitute significant sources of data anomalies that affect the accuracy and reliability of information necessary to manage spill and TDG in the Columbia and Snake rivers. The data base that was reviewed covers 25 selected Columbia and Snake river stations, and includes real-time TDG data needed to regulate spill operations to maintain gas levels within state water quality standards and to monitor effects on fish and aquatic life during the salmon migration season. A wide range of anomalies (daily averages missing or in error or based on incomplete records) was detected in more than one-third (37 percent) of the Corps' gas data base. Extreme anomalies (daily averages including errors and discontinuities for more than eight hours in a day) were found in 16 percent of the data base. The Fish Passage Center, also reviewed the Corps' data and reported an overall 33 percent incidence of anomalous days. Despite arriving at similar findings about the Corps' data base, we detected a 28 percent discrepancy in the type of data anomalies between our analyses. Real. time improvements in the quality of the dissolved gas data base are necessary to provide managers with a reliable product from this monitoring effort.     

草原旅游资源深度开发研究——以内蒙古自治区为例

旅游资源是构成旅游业发展的基础，草原旅游资源的合理利用与深度开发具有重要意义。着眼于内蒙古草原旅游现状，通过分析内蒙古草原旅游资源的特征和深度开发的必要性与可行性，提出开发理念、开发模式、区域合作和产品开发方面的设想，尤其基于资源的状况提出3种资源开发模式：依托市场模式、组合集聚模式和依托资源模式。