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1.
本文分析了气候试验箱升降温控制中产生温度过冲及影响温湿度控制精度的原因,针对试验箱采用的各种温度控制方法、试验箱(室)本身的大小以及温度控制精度要求的高低等不同情况,提出相应的改进措施,并说明了适当对加湿水温度和风速进行控制及提高试验箱密封性,也是提高温湿度控制精度的有效途径。  相似文献   

2.
螺丝壳山风景区保健旅游的环境与气候   总被引:1,自引:0,他引:1  
刘以礼 《四川环境》2004,23(5):11-13
螺丝壳山风景区风光秀美,其空气和水环境质量良好,低日照、低太阳辐射、湿润、低风速等气候有利于保健美容;并随着全球环境污染、气候变化而越来越体现其价值。  相似文献   

3.
在气候试验设备检定过程中,经常存在温度场实际温度与设备指示温度不相一致的情况,通过对设备温度场的适当调整,可使温度场温度保持所需要的标称温度,以保证环境试验的准确性和真实性。  相似文献   

4.
前人对吐鲁番农田防护林的防护效益曾有过许多观测研究,但缺少年周期变化的气象效益观测结果。通过利用吐鲁番红族治沙站农田林网内和旷野建立的气象观测站点收采的全年观测资料,分别选择春季、冬季和风季各一个月的气象资料,对有防护林网保护和无防护林网保护的气温、地表温度和风速的变化进行对比分析证明,防护林网改善小气候的作用随季节变化而发生变化。其中,防风效果最为显著,风速为16.2m/s时,株网内风速可降低61.8%-75.4%;风速为2.0m/s时,林网内风速降低90%左右或无风。林网对气温调节随节发生变化,1月增温,7月降温,而3月风季的前半月有增温作用,下半月却不明显。但各月增降的幅度不大。林网在各月对地表温度普遍都有提高,其中5月提高幅度最大可达20℃左右。  相似文献   

5.
本文针对现行混凝土温度-应力试验机存在的不足,结合国家"211工程"项目要求,设计了一种新型环境箱,可用于研究温度,湿度和风速变化对混凝土的影响.创新性的采用了管道分流和内置加湿结构,可实现高精度的温度、湿度和风速调节.  相似文献   

6.
青海省气候异常的部分事实揭示   总被引:1,自引:0,他引:1  
王志俊 《青海环境》1997,7(3):112-117
利用青海省均一性、代表性都较好的5个气象站点自建站至1996年历年1月和7月平均气温和降水量资料,分析了省内各主要气候区的温度、降水异常状况。结果表明各地气温异常偏高或偏低的年份较为一致,而水降水异常则呈现出很强的局地性特点。  相似文献   

7.
美国军用标准MIL—STD—810早就成为美国环境试验的“圣经”。题为“航空航天和地面武器环境试验方法”的64页的资料,作为美国空军文献,最初于1962年6月14日出版,该文献后来发展成为450页的美国军用标准MIL-STD-810E“环境试验方法及工程导则”。在编制美国军用标准810的较早版本时,几乎没有重视或注意环境或有关技术领域内的国际工作。 在1979年的美国和德国有关人员的会谈中,与会者承认,各个技术领域内的双边会谈将大大有利于双方国家。我们不仅能分享技术,而且我们可以制定出双方都可接受的文件。如果在拟定试验时已取得同意的话,假使武器最后被对方国家购买或使用,那么这个国家不必再重复试验。  相似文献   

8.
从气候试验设备的功能、控制方式、制冷形式、循环系统等方面通过技术发展过程的回顾,展示气候试验设备当代的技术水平,对于促进我国试验设备研制技术的进步和指导设备的订购选型都有一定的指导意义和参考价值。  相似文献   

9.
介绍作者从五十年代开始从事气候环境试验方法,标准及设备的开发设计所积累的长期经验,在退休前加以总结综合运用,设计研究成FS-35型化学气体腐蚀与气体环境试验箱,以适应湿热试验,长霉试验,盐等数个标准试验方法,具有多功能试验箱特点,并达到了国内先进水平。  相似文献   

10.
都兰县近40年气候资源变化特征分析   总被引:2,自引:0,他引:2  
陈芳  吴振杰 《青海环境》2002,12(4):144-148
利用都兰县1961-2000年40年气象资料,运用统计学方法,对光、热、水等气候资源以及蒸发、风等气象要素的变化进行了分析,揭示了气候资源变化的基本事实和变化规律。结果表明:随着全球气候的变暖,近40年来,都兰县平均气温以0.269℃/10a的气候倾向率呈较明显的增温趋势,进入20世纪90年代升温趋势更加明显;气温≥0℃、≥5℃和≥10℃期间的积温均呈上升趋势,其中,≥10℃期间的积温上升趋势最为明显;年和汛期降水量增加,夏季降水量增加尤为明显;日照时数、蒸发和风速的年际变化呈下降趋势。  相似文献   

11.
Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.  相似文献   

12.
Urban ecological systems: scientific foundations and a decade of progress   总被引:9,自引:0,他引:9  
Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.  相似文献   

13.
Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.  相似文献   

14.
In water stressed regions, water managers are exploring new horizons that would help in long‐range streamflow forecasts. Oceanic‐atmospheric oscillations have been shown to influence streamflow variability. In this study, long‐lead time streamflow forecasts are made using a multiclass kernel‐based data‐driven support vector machine (SVM) model. The extended streamflow records based on tree ring reconstructions were used to provide a longer time series data. Reconstructed data were used from 1658 to 1952 and the instrumental record was used from 1953 to 2007. Reconstructions for oceanic‐atmospheric oscillations included the El Niño‐Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and North Atlantic Oscillation. Streamflow forecasts using all four oscillations were made with one‐year to five‐year lead times for 21 gages in the western United States. This is the first study that uses both instrumental and reconstructed data of oscillations in SVM model to improve streamflow forecast lead time. SVM model was able to provide “satisfactory” to “very good” forecasts with one‐ to five‐year lead time for the selected gages. The use of all the oscillation indices helped in achieving better predictability compared to using individual oscillations. The SVM modeling results are better when compared with multiple linear regression model forecasts. The findings are statistical in nature and are expected to be useful for long‐term water resources planning and management.  相似文献   

15.
Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.  相似文献   

16.
ABSTRACT: Mathematical models for predicting watershed surface flow responses are available, most of which are elaborate nonlinear numerical surface and channel flow models linked with infiltration models. Such models may be used to make predictions for ungaged areas, assuming an acceptable fitting of the model to the topography and roughness of the real system. For some application purposes, these models are impractical because of their complexity and expensive computer solutions. A procedure is developed that uses a complex model of an ungaged area to derive a simpler parametric nonlinear system model for repetitious simulation with input sequences. The predicted flow outputs are obtained with the simpler model at significant savings of money and time. The procedures for constructing a complex kinematic model of a 40 acre (161,880 m2) reference watershed and deriving the simpler system model are outlined. The results of predictions from both models are compared with a selected set of measured events, all having essentially the same initial conditions. Peak discharges ranged from 3 to 118 ft3/sec (0.085 to 3.34 m3/sec), which includes the largest event of record. The inherent limitations of lumped systems models are demonstrated, including the bias caused by their inability to model infiltration losses after rainfall ceases. Computer costs and times for the models were compared. The derived simple model has a cost advantage when repeated use of a model is required. Such an applications hydrologic model has an engineering tradeoff of reduced accuracy, and lumping bias, but is more economical for certain design purposes.  相似文献   

17.
Manganese entering impounded water will undergo a cyclic transformation. Oxidation precipitates manganese from top waters. At the bottom of the lake, biological activity will render manganese soluble by both intracellular as well as extracellular activity. The study was made to demonstrate that biological reduction and transformation, organometallic complexation, together with the presence of carbon dioxide and the lowering of pH all have some effect on the solubility of manganese. Dissolved manganese may be brought back to top waters during the lake overturn and therefore deteriorates the water quality.  相似文献   

18.
Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224kgPha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10gWTRkg(-1) soil. BAP loss masses were greater in leachate (16.4-536mg) than in runoff (0.91-46mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source.  相似文献   

19.
The SPARROW (SPAtially Referenced Regression on Watershed attributes) model was used to simulate annual phosphorus loads and concentrations in unmonitored stream reaches in California, U.S., and portions of Nevada and Oregon. The model was calibrated using de‐trended streamflow and phosphorus concentration data at 80 locations. The model explained 91% of the variability in loads and 51% of the variability in yields for a base year of 2002. Point sources, geological background, and cultivated land were significant sources. Variables used to explain delivery of phosphorus from land to water were precipitation and soil clay content. Aquatic loss of phosphorus was significant in streams of all sizes, with the greatest decay predicted in small‐ and intermediate‐sized streams. Geological sources, including volcanic rocks and shales, were the principal control on concentrations and loads in many regions. Some localized formations such as the Monterey shale of southern California are important sources of phosphorus and may contribute to elevated stream concentrations. Many of the larger point source facilities were located in downstream areas, near the ocean, and do not affect inland streams except for a few locations. Large areas of cultivated land result in phosphorus load increases, but do not necessarily increase the loads above those of geological background in some cases because of local hydrology, which limits the potential of phosphorus transport from land to streams.  相似文献   

20.
The interactions between humans, animals and the environment have shaped human values and ethics, not only the genes that we are made of. The animal rights movement challenges human beings to reconsider interactions between humans and other animals, and maybe connected to the environmental movement that begs us to recognize the fact that there are symbiotic relationships between humans and all other organisms. The first part of this paper looks at types of bioethics, the implications of autonomy and the value of being alive. Then the level of consciousness of these relationships are explored in survey results from Asia and the Pacific, especially in the 1993 International Bioethics Survey conducted in Australia, Hong Kong, India, Israel, Japan, New Zealand, The Philippines, Russia, Singapore and Thailand. Very few mentioned animal consciousness in the survey, but there were more biocentric comments in Australia and Japan; and more comments with the idea of harmony including humans in Thailand. Comparisons between questions and surveys will also be made, in an attempt to describe what people imagine animal consciousness to be, and whether this relates to human ethics of the relationships. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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