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。     

配置不同类型探测器的X射线荧光测厚仪对比研究

X射线荧光测厚法是对电子元器件金属镀层厚度进行测量的主要方法之一。本文对X射线荧光测厚仪的工作原理、结构进行了分析,对其核心组成部分探测器的三种类型的性能参数进行了对比,并选取相应型号的测厚仪进行了对比测试,对测量结果进行了分析。     

整车腐蚀试验的车辆拆解与评价分析

只有选择合理的拆解方式,并对其结果进行评价与分析,才能对车企产品的防腐研究具有重要的指导意义。对腐蚀试验车的拆解进行简述,并对拆解后如何进行评价提出个人的观点。     

长春市伊通河COD及TOC相关性研究

采集长春市伊通河伊通大桥河段的水样,对其TOC和COD值进行了实验测定,并对测得数据进行回归分析,研究二者的相关性。据此对伊通河水体有机污染的状况及其变化规律进行分析。     

生态旅游景区管理的游客满意度动态监测-以香格里拉碧塔海景区为例

对生态旅游景区的游客满意度进行动态监测,能够有效地了解景区的管理质量,对保证生态旅游的可持续发展有着非常重要的意义.以香格里拉碧塔海生态旅游景区为例,采用问卷调查的方法对游客的满意度进行了监测研究,并对调查结果进行了系统分析,以了解景区的管理质量.     

青海省海东地区城镇供水现状及前景综述

文章通过对海东6县各城镇集中式供水的现状进行调查，对近远期供水进行合理规划，对城镇供水工程进行供水前景分析，从而保障城镇供水的水量充足，水质优良，水源生态系统良性循环，促进社会经济可持续发展。     

保温材料的密度对非稳态测试过程影响的数值模拟研究

本文采用数值模拟的方法对保温材料的密度对台架试验箱的非稳态测试过程的影响进行了研究。得出并分析了保温材料的密度对非稳态热传导过程中的非正规状态、正规状态阶段及试验箱内温度均匀度的影响程度。最后,对本文进行了总结,并对未来的研究方向进行了展望。     

试论集安生态立市战略的实施

对集安市生态立市战略的确立和实施情况进行了介绍,对集安市生态建设的优势和特点进行了分析,并针对集安市如何进行生态立市建设提出了建议。     

基于时间序列修正算法的我国入境旅游人数预测

为了对我国入境旅游游客量进行准确预测,提出一种将ARIMA模型与RBF神经网络相结合的算法。以我国2009年1月到2014年4月我国入境旅游游客量月度数据为研究对象,利用该模型对我国入境旅游游客量进行初步预测,计算残差,再利用RBF神经网络对残差进行拟合预测,并对ARIMA预测结果进行修正。结果表明:利用RBF神经网络对ARIMA模型进行修正,将线性拟合算法和非线性拟合算法结合起来用于我国入境旅游游客量预测是一种较可靠的算法。     

垃圾焚烧处理二恶英的产生及控制

本文对垃圾焚烧过程中二恶英的产生机理进行了简要分析,并对如何控制二恶英的产生及污染进行了论述.     

茶园节肢动物群落数量动态研究

从群落生态学的角度对茶园节肢动物群落动态变化进行了初步探讨.通过对安徽省黄山市休宁县农家茶园的调查,获得了关于茶园节肢动物群落的组成、个体数量及其物种数等数据.结果表明,4-5月份茶园一般不需要进行施药防治,此时天敌种类和数量相对较多,对害虫起控制作用,这一时期应做好害虫测报和防治准备,为茶农防治茶园害虫提供科学方法.     

开发云南省生物资源产业的可持续发展研究

本文论述了云南省生物资源开发产业的现状,重点探讨了生物资源开发利用中存在的主要问题,指出了今后云南开发生物资源产业应从云南实际出发,走开发利用与保护并举的可持续发展道路,并提出了相应的对策     

人口增长与自然资源

目前,世界人口政策所面临的突出问题是人口的增长与土地、淡水、动物、植物等自然资源和环境等方面的不平衡。人口的急剧增长加重了自然资源的压力,削弱了可再生资源的生产能力,在很大程度上使自然资源遭到严重的破坏。本文分析了人口增长与土地利用、森林资源、水资源、生物资源、能源和海洋资源的相互关系,指出确保人口增长与自然资源的产量和物种保护协调一致的唯一出路是严格控制人口数量增长。从另一个方面,反映了自然资源开发与保护的重要意义。     

浙江省自然保护区的特点与意义

自然保护区对维护生态环境,保护生物资源,维持生物多样性具有重要意义．本文论述了浙江省自然保护区的特点,探讨了它们的重要意义．     

Conservation Biological Control and Pest Performance in Lawn Turf: Does Mowing Height Matter?

With >80 million United States households engaged in lawn and gardening activities, increasing sustainability of lawn care is important. Mowing height is an easily manipulated aspect of lawn management. We tested the hypothesis that elevated mowing of tall fescue lawn grass promotes a larger, more diverse community of arthropod natural enemies which in turn provides stronger biological control services, and the corollary hypothesis that doing so also renders the turf itself less suitable for growth of insect pests. Turf-type tall fescue was mowed low (6.4 cm) or high (10.2 cm) for two growing seasons, natural enemy populations were assessed by vacuum sampling, pitfall traps, and ant baits, and predation and parasitism were evaluated with sentinel prey caterpillars, grubs, and eggs. In addition, foliage-feeding caterpillars and root-feeding scarab grubs were confined in the turf to evaluate their performance. Although some predatory groups (e.g., rove beetles and spiders) were more abundant in high-mowed grass, predation rates were uniformly high because ants, the dominant predators, were similarly abundant regardless of mowing height. Lower canopy temperatures in high-mowed grass were associated with slower growth of grass-feeding caterpillars. Higher lawn mowing reduces fuel consumption and yard waste, and promotes a deep, robust root system that reduces need for water and chemical inputs. Although in this study elevated mowing height did not measurably increase the already-high levels of predation, it did suggest additional ways through which bottom-up effects on insect pest growth might interact with natural enemies to facilitate conservation biological control.     

Policy and reality of Environmentally Sensitive Areas in Whitman County,Washington, USA

The Washington State Environmental Policy Act (SEPA) promotes the conservation of natural resources through procedural review of proposed actions which may impact natural systems. There are, however, many actions specifically exempt from the SEPA review process. Since many exempt actions could have significant adverse effects on natural resources at one location and not another, the SEPA statute contains a provision that enables local governments to designate Environmentally Sensitive Areas (ESAs). Within the ESAs, these potentially adverse activities are subject to SEPA review. Local governments have complete control over the exact definition of the ESA criteria and the types of local projects exempt from SEPA. Whitman County, the most productive wheat-producing county in Washington, has recognized the need for conservation of its natural resources in its comprehensive plan but has not implemented the ESA provision. A representative watershed within Whitman County was used as a case study to identify areas which would qualify for ESA status. In these areas, specific soil, water, and biological characteristics or resources were identified as sensitive to certain common land uses. Significant differences were found between state and county policies regarding ESAs and actual conditions within the watershed. It may be more effective for the state to manage ESAs on a consistent and regional basis.     

Vegetational designs for insect-habitat management

Insect habitats in anthropocentric ecosystems consist of crop plants or forest trees and the coexisting non-crop vegetation. The manipulation of the spatial and temporal arrangement of these plant communities can trigger direct or indirect effects on insect pest populations and their associated natural enemy complexes. In this article habitat management is viewed as a technique to design plant associations that support populations of natural enemies or that exert deterrent effects on herbivorous insects.     

Multiple-resource modeling as a tool for conservation: Its applicability in Mexico

The current Mexican environmental law provides the legal basis for comprehensive land-use planning. Under the law, development of natural ecosystems must combine goals, policies, and practices towards the sustainable use of natural resources and the protection of biological diversity. Thus, ecosystem manipulation must be able to counter fragmentation of natural ecosystems and isolation of natural reserves, while providing for human needs. Assessment of the potential of natural ecosystems and management impacts are required. Multiple-resource simulation is an assessment and land-use planning tool that permits managers and decision makers to comply with the law, providing a flexible, user-oriented system that can meet the needs of managers, conservationists, and researchers. A multiple-resource model and an example of how it can be applied to meet planning needs is presented for discussion.     

The Ecological and Environmental Characteristics and Conservation of the Wetlands in the Changjiang Estuary, China

The natural wetlands in the Changjiang Estuary, China are important ecologically. The total area of the wetlands in the Changjiang Estuary amounts to 215000 ha. The wetlands consist of littoral and sandy estuarine island areas, and are rich in biological resources. There are 136 species of vascular plant, 150 species of bird, and 68 species of benthic macro-invertebrate in the wetlands. However, the wetland in the Changjiang Estuary is a vulnerable ecosystem. Development of the wetland is mainly influenced by intensive human reclamation, pollution, movement of sediments in the Changjiang River, and the effects of tides and waves. Investigations have shown that maintaining biodiversity, providing resources for the living organisms, purifying environments and resisting natural hazards could be regarded as important functions for the protection of the wetlands. It is proposed that sustainable principles should be supported in developing the wetlands in the future.     

Garrett hardin: Dilemmas and taboos

Summary Garrett Hardin has written extensively about the biological, ecological and social impacts of various approaches to allocating natural resources. His work has been based largely upon the theory of the tragedy of the commons, population genetics and the application of biological principles to analogous social processes. He points out that policies that are morally appealing, because of their short-term benefits, may lead to disaster in the years ahead. His recommendations have stimulated considerable controversy and have been the object of moral criticism. They should not, however, be dismissed without careful consideration. Ralph H. Lutts is director of a natural history museum and an environmental education center. He is also adjunct assistant professor of environmental studies in the School of Natural Science of Hampshire College, Amherst, Massachusetts. His research interests are in environmental ethics and history.