首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   9篇
  免费   1篇
安全科学   1篇
废物处理   2篇
综合类   1篇
基础理论   1篇
污染及防治   2篇
评价与监测   2篇
社会与环境   1篇
  2016年   3篇
  2013年   1篇
  2010年   1篇
  2005年   1篇
  2004年   2篇
  2003年   1篇
  2002年   1篇
排序方式: 共有10条查询结果,搜索用时 845 毫秒
1
1.
In the periods of summer and autumn bloom of the Stephanodiscus hantzschii Crun. in recreational water bodies, studies on the vertical distribution of chlorophyll a, its contents per unit biomass, efficiency in using photosynthetically active radiation (EPhAR), and assimilative activity of microalgae were performed. The results confirmed the existence of two ecophysiological forms of St. hantzschii and provided evidence that both forms are typically autotrophic and can efficiently use low-intensity PhAR for photosynthesis.  相似文献   
2.
The provision of energy for households is a major contributor to greenhouse gas emissions in the domestic sector. There is significant scope for energy savings and thus emission reduction in this sector. This paper constructs a bridge between thermal analysis and environmental assessment in the occupancy stage of the dwelling life cycle, approaching both methods as being on a common system Environment–Dwelling–Inhabitant. The importance of the local level in the thermal analysis and assessment of either a dwelling or an inhabitant's behaviour is demonstrated. It is shown that the researcher can choose between natural experiment, computer experiment and mathematical modelling to analyze the system. Such a choice is discussed for two particular methods of thermal analysis. Thermal Nomograms are the result of mathematical modelling, and the Energy Score Sheet is the result of a computer experiment in energy rating. Despite being developed for the purpose of thermal analysis, these methods can also be utilized for environmental assessment at the local level. The discussion centres on Australian conditions where the majority of the population resides in a relatively benign climate wherein behavioural alterations have significant potential for energy savings and environmental impact. The purpose of the paper is to emphasise benefits apart from energy minimisation to promote the use of energy efficient housing strategies.  相似文献   
3.
人类活动严重地改变了里海地区的生态系统,最主要的影响是引起了生态系统中水流的改变和水质的恶化.地区环境的改变已经影响到了这一地区经济的发展,对鱼类资源的影响尤其明显.专家们利用GIwA计划中得出的一套方法,对这一地区共享水域中最重要的跨边界问题进行了评估.本报告关注促使这一地区环境改变的最重要的根本原因:生境和生物群落的改变.  相似文献   
4.
Environmental changes strongly impact the distribution of species and subsequently the composition of species assemblages. Although most community ecology studies represent temporal snap shots, long‐term observations are rather rare. However, only such time series allow the identification of species composition shifts over several decades or even centuries. We analyzed changes in the species composition of a southeastern German butterfly and burnet moth community over nearly 2 centuries (1840–2013). We classified all species observed over this period according to their ecological tolerance, thereby assessing their degree of habitat specialisation. This classification was based on traits of the butterfly and burnet moth species and on their larval host plants. We collected data on temperature and precipitation for our study area over the same period. The number of species declined substantially from 1840 (117 species) to 2013 (71 species). The proportion of habitat specialists decreased, and most of these are currently endangered. In contrast, the proportion of habitat generalists increased. Species with restricted dispersal behavior and species in need of areas poor in soil nutrients had severe losses. Furthermore, our data indicated a decrease in species composition similarity between different decades over time. These data on species composition changes and the general trends of modifications may reflect effects from climate change and atmospheric nitrogen loads, as indicated by the ecological characteristics of host plant species and local changes in habitat configuration with increasing fragmentation. Our observation of major declines over time of currently threatened and protected species shows the importance of efficient conservation strategies.  相似文献   
5.
Purpose. The purpose of this particular study was to test a newly created instrument in describing the facilitators and barriers to occupational health and safety in small and medium-sized enterprises (SMEs) in Ontario, Canada. Methods. A cross-sectional design was used to identify the occupational health and safety culture of SMEs in public and private sectors in Ontario. Results. A total of 153 questionnaires were completed. The majority of respondents were female (84%) with a mean age of 49.8 years (SD 10.6). Seventy-four percent were supervisors. Seventy percent of respondents were from the private sector while 30% derived from the public sector including healthcare, community services, and non-profit organizations. Further, conducting regular external safety inspections of the workplace was found to be statistically associated with a safe work environment 2.88 95% CI [1.57, 5.27]. Conclusions. Strategies and training opportunities that focus on how to adapt occupational health and safety legislation to the nature and diversity of SMEs are recommended. Furthermore, employers may use such information to improve safety in their SMEs, while researchers can hopefully use such evidence to develop interventions that are applicable to meeting the occupational health and safety needs of SMEs.  相似文献   
6.
A pilot phytoremediation project was conducted at the Mukluk site in Sprague, Connecticut, formerly a private skeet shooting range. A series of experiments was conducted to investigate if any plants can be effective lead phytoextractors for this site that has very high soil lead concentrations and low soil pH. Greenhouse screening of plants for lead resistance and accumulation using field soil was implemented as the initial step before the field installation. Herbaceous plant species with known lead phytoextraction capabilities included Indian mustard and blue fescue; a few willow clones with purported heavy metal resistance were also tested. Based on the results of the greenhouse experiments, blue fescue appeared to be sensitive to high lead concentration in soil, and only willows and Indian mustard along with various soil amendments were selected for the field installation. Indian mustard grew poorly in most of the treatments at the site except in the compost and lime treatment. Lead accumulation by this species was low in all treatments. In contrast, willows showed tolerance to very high lead concentrations present in the soil and were able to uptake and translocate lead into aboveground tissues. However, lead content in aerial tissues was low, and no change in soil lead concentration at the site was recorded post‐harvest after one growing season. It appeared that highly unfavorable soil characteristics at the Mukluk site complicated the species selection, and no effective phytoextractors have been found for this location. These suggest that the feasibility of phytostabilization and possible production of biofuel from willow biomass on these types of sites should be further investigated. © 2010 Wiley Periodicals, Inc.  相似文献   
7.

Supported Fe2O3/WO3 nanocomposites were fabricated by an original vapor phase approach, involving the chemical vapor deposition (CVD) of Fe2O3 on Ti sheets and the subsequent radio frequency (RF)-sputtering of WO3. Particular attention was dedicated to the control of the W/Fe ratio, in order to tailor the composition of the resulting materials. The target systems were analyzed by the joint use of complementary techniques, that is, X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDXS), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), and optical absorption spectroscopy. The results showed the uniform decoration of α-Fe2O3 (hematite) globular particles by tiny WO3 aggregates, whose content could be controlled by modulations of the sole sputtering time. The photocatalytic degradation of phenol in the liquid phase was selected as a test reaction for a preliminary investigation of the system behavior in wastewater treatment applications. The system activity under both UV and Vis light illumination may open doors for further material optimization in view of real-world end-uses.

  相似文献   
8.
Biotechnology for aerobic conversion of food waste into organic fertilizer.   总被引:1,自引:0,他引:1  
A biotechnology for aerobic conversion of food waste into organic fertilizer under controlled aeration, stirring, pH and temperature at 55-65 degrees C, is proposed. To maintain neutral pH at the beginning of the bioconversion 5% CaCO3 was added to the total solids of the food waste. The addition of 20% horticultural waste compost as a bulking agent to the food wastes (w.w./w.w.), improved the bioconversion and increased the stability of the final product. No starter culture was needed for aerobic bioconversion of food waste into organic fertilizer for 10 days. The low contents of heavy metals in the raw materials used in the bioconversions ensured the safety of fertilizer from food waste for application in agriculture. The addition of 4% organic fertilizer to the subsoil increased the yield and growth of Ipomoea aquatica (Kang Kong) by 1.5 to 2 times. The addition of phosphorus is required to enhance the positive effect of organic fertilizer on plant growth.  相似文献   
9.
Advancing land degradation in the irrigated areas of Central Asia hinders sustainable development of this predominantly agricultural region. To support decisions on mitigating cropland degradation, this study combines linear trend analysis and spatial logistic regression modeling to expose a land degradation trend in the Khorezm region, Uzbekistan, and to analyze the causes. Time series of the 250-m MODIS NDVI, summed over the growing seasons of 2000–2010, were used to derive areas with an apparent negative vegetation trend; this was interpreted as an indicator of land degradation. About one third (161,000 ha) of the region’s area experienced negative trends of different magnitude. The vegetation decline was particularly evident on the low-fertility lands bordering on the natural sandy desert, suggesting that these areas should be prioritized in mitigation planning. The results of logistic modeling indicate that the spatial pattern of the observed trend is mainly associated with the level of the groundwater table (odds?=?330 %), land-use intensity (odds?=?103 %), low soil quality (odds?=?49 %), slope (odds?=?29 %), and salinity of the groundwater (odds?=?26 %). Areas, threatened by land degradation, were mapped by fitting the estimated model parameters to available data. The elaborated approach, combining remote-sensing and GIS, can form the basis for developing a common tool for monitoring land degradation trends in irrigated croplands of Central Asia.  相似文献   
10.
Barannik V  Borysova O  Stolberg F 《Ambio》2004,33(1-2):45-51
Ecosystems in the Caspian Sea region have been heavily modified by anthropogenic activities, mainly as a result of changes in the water flow and degradation of the water quality in the ecosystems. Changes in the regional environment have influenced regional economies, particularly obvious in the impacts on fish stocks. Using the methodology developed in the GIWA project, experts in the region carried out an assessment of the most important transboundary issues in shared waters in the region. This report focuses on the root causes for the most important drivers of environmental change in the region: habitat and community modification.  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号