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41.
户外运动服装的开发及发展趋势探析   总被引:2,自引:1,他引:1  
随着生活方式的多元化发展,户外运动受到越来越多人的关注和喜爱。户外运动用品店如雨后春笋应运而生。因此具有防护功能的户外运动服装特别受到青睐。本文综述了户外运动服装的需求和分类,分析了户外运动服装的结构和功能性设计思路,并论述了未来户外运动服装的发展趋势。  相似文献   
42.
This study investigated the water quality variation spanning 30 years (1986–2017) in 16 catchments of Hong Kong against different urbanization indices, namely, built area fraction; population; and product of population and built area fraction. Pearson correlations of three different periods of time (1988–1990, 1998–2000, and 2015–2017) indicated that water quality trends were dependent on the urbanization index. Total solids, nitrite-nitrogen, total phosphorus, electrical conductivity, dissolved oxygen, and flow rate had significant deteriorative trends (Pearson r > 0.5 and p < 0.05) with population and product of built area and population. Results also interpreted that built area fraction and product of built area and population were the worst and best indices that represented urbanization and/or its impacts, respectively. Mann-Kendall test for the entire 30 year period showed that water quality had improved with time with respect to certain water quality parameters (e.g., dissolved oxygen, ammoniacal nitrogen and total suspended solids). The results portrayed that although the urbanization of catchments had increased with time, the river water quality with respect to many parameters showed signs of improvement and the legislative measures implemented seemed to be effective in controlling pollution.  相似文献   
43.
Estimates of biodiversity change are essential for the management and conservation of ecosystems. Accurate estimates rely on selecting representative sites, but monitoring often focuses on sites of special interest. How such site-selection biases influence estimates of biodiversity change is largely unknown. Site-selection bias potentially occurs across four major sources of biodiversity data, decreasing in likelihood from citizen science, museums, national park monitoring, and academic research. We defined site-selection bias as a preference for sites that are either densely populated (i.e., abundance bias) or species rich (i.e., richness bias). We simulated biodiversity change in a virtual landscape and tracked the observed biodiversity at a sampled site. The site was selected either randomly or with a site-selection bias. We used a simple spatially resolved, individual-based model to predict the movement or dispersal of individuals in and out of the chosen sampling site. Site-selection bias exaggerated estimates of biodiversity loss in sites selected with a bias by on average 300–400% compared with randomly selected sites. Based on our simulations, site-selection bias resulted in positive trends being estimated as negative trends: richness increase was estimated as 0.1 in randomly selected sites, whereas sites selected with a bias showed a richness change of −0.1 to −0.2 on average. Thus, site-selection bias may falsely indicate decreases in biodiversity. We varied sampling design and characteristics of the species and found that site-selection biases were strongest in short time series, for small grains, organisms with low dispersal ability, large regional species pools, and strong spatial aggregation. Based on these findings, to minimize site-selection bias, we recommend use of systematic site-selection schemes; maximizing sampling area; calculating biodiversity measures cumulatively across plots; and use of biodiversity measures that are less sensitive to rare species, such as the effective number of species. Awareness of the potential impact of site-selection bias is needed for biodiversity monitoring, the design of new studies on biodiversity change, and the interpretation of existing data.  相似文献   
44.
成都市冬季大气颗粒物组成特征及来源变化趋势   总被引:7,自引:0,他引:7  
年冬季分别在成都市8个环境受体采样点采集PM10、PM2.5样品,同时采集颗粒物源类样品,分析上述样品质量浓度及多种无机元素、水溶性离子和碳组分的含量,以对这3 a冬季大气颗粒物浓度、特征组分、来源及变化趋势进行分析. 使用CMB-iteration模型对成都市中心城区的PM10、PM2.5进行来源解析. 结果表明: 成都市冬季ρ(PM10)在工业区最高,PM2.5污染呈现区域性特征;冬季PM10的主要来源有扬尘、二次硫酸盐、煤烟尘、二次硝酸盐和机动车尾气尘,上述5类源在2010─2012年的分担率分别为24%~29%、17%~22%、13%~16%、6%~12%、6%~11%;对PM2.5有重要贡献的源类有二次硫酸盐、扬尘、煤烟尘、二次硝酸盐和机动车尾气尘,这5类源在2010─2012年的分担率范围分别为25%~27%、19%~22%、12%~15%、11%~13%、8%~11%. 二次粒子、扬尘等是成都市大气颗粒物的主要污染源,其中扬尘、建筑水泥尘等以粗粒子为主的源类浓度贡献呈逐年下降趋势,而二次粒子等以细粒子为主的源类浓度贡献则逐年上升,成都市冬季大气细颗粒物污染加重.   相似文献   
45.
The main results of research work carried out since 1998 with regard to the application of hydro-acoustic technologies for the evaluation of biomass and distribution of small pelagic fish species off the southern coast of Sicily are presented, taking into account information from hydrology and from ecology of the fish populations targeted. The biomass estimates and the population‐density charts presented concern the two main species, i.e. sardine Sardina pilchardus (Walbaum, 1792) and anchovy Engraulis encrasicolus (Linnaeus, 1758). Both the sardine and anchovy populations experienced large inter-annual fluctuations, with biomass estimates ranging from 6000 to over 36,000 tonnes (t) (sardine) and from about 7000 to 23,000 t (anchovy). Acoustic estimates are largely consistent with landings recorded in Sciacca (the main fishing port for small pelagic species in the study area) during the year following the evaluation surveys. In addition, trends in sardine and anchovy biomass estimates appears to be negatively correlated with the mean sea surface temperature calculated over the time intervals January–September (sardine) and June–November (anchovy) of the preceding year, which correspond to larval and juvenile growth periods of target species. Observed patterns would suggest the importance of enrichment processes relevant to the survival of early stages, so determining recruitment success and finally higher population sizes.  相似文献   
46.
从几个方面重点介绍了循环经济的国际发展趋势;把发展循环经济纳入法制化轨道;形成政府倡导、全民参与的意识和环境;大力促进循环经济产业化;鼓励技术创新,促进循环经济的发展。为我国发展循环经济,实现全面建设小康社会目标提供借鉴经验。  相似文献   
47.
The Oxford Commission on Sustainable Consumption aims to promote debate and action to achieve sustainable consumption. It has met four times since it was established in 1999. Commission members have undertaken a number of projects around the world, working with communities to explore pathways to more sustainable consumption. This paper summarises the Commission’s progress and the messages emerging from its work. Current consumption trends are supported by a number of social trends, including individualisation, the spread of the market ethos, urbanisation, globalisation, and the increasing awareness of risk and uncertainty. However, these trends contain the seeds of their own limitation. In particular, increasing discourse about ethics and social goals may be the key to a shift towards more sustainable consumption.  相似文献   
48.
Long-term study of air pollution plays a decisive role in formulating and refining pollution control strategies. In this study, two 12-month measurements of PM2.5 mass and speciation were conducted in 00/01 and 04/05 to determine long-term trend and spatial variations of PM2.5 mass and chemical composition in Hong Kong. This study covered three sites with different land-use characteristics, namely roadside, urban, and rural environments. The highest annual average PM2.5 concentration was observed at the roadside site (58.0±2.0 μg m−3 (average±2σ) in 00/01 and 53.0±2.7 μg m−3 in 04/05), followed by the urban site (33.9±2.5 μg m−3 in 00/01 and 39.0±2.0 μg m−3 in 04/05), and the rural site (23.7±1.9 μg m−3 in 00/01 and 28.4±2.4 μg m−3 in 04/05). The lowest PM2.5 level measured at the rural site was still higher than the United States’ annual average National Ambient Air Quality Standard of 15 μg m−3. As expected, seasonal variations of PM2.5 mass concentration at the three sites were similar: higher in autumn/winter and lower in summer. Comparing PM2.5 data in 04/05 with those collected in 00/01, a reduction in PM2.5 mass concentration at the roadside (8.7%) but an increase at the urban (15%) and rural (20%) sites were observed. The reduction of PM2.5 at the roadside was attributed to the decrease of carbonaceous aerosols (organic carbon and elemental carbon) (>30%), indicating the effective control of motor vehicle emissions over the period. On the other hand, the sulfate concentration at the three sites was consistent regardless of different land-use characteristics in both studies. The lack of spatial variation of sulfate concentrations in PM2.5 implied its origin of regional contribution. Moreover, over 36% growth in sulfate concentration was found from 00/01 to 04/05, suggesting a significant increase in regional sulfate pollution over the years. More quantitative techniques such as receptor models and chemical transport models are required to assess the temporal variations of source contributions to ambient PM2.5 mass and chemical speciation in Hong Kong.  相似文献   
49.
本文通过种群自我调节的规律以及Leslie模型进行数量动态分析,从而提出了次生林数量动态与经营的生态经济对策。  相似文献   
50.
曹禹  董小棠  邵雪婷  刘琳  王德高 《环境科学》2021,42(12):5912-5920
毒品滥用问题是全球广泛关注的社会问题,对城市毒品滥用情况进行长期监测具有重要意义.采用污水流行病学的方法,对大连市毒品的滥用情况进行连续长期调查.2020~2021年采集大连市22个污水处理厂的进口污水,通过气相色谱衍生化方法分析测定甲基苯丙胺、海洛因、氯胺酮、摇头丸和可卡因的生物标志物的浓度,即其尿液代谢产物甲基苯丙胺、吗啡、氯胺酮、摇头丸和苯甲酰芽子碱.结果表明,2020年p(甲基苯丙胺)、p(吗啡)和p(氯胺酮)均值分别为23.69、23.21和2.40 ng·L-1;2021年均值分别为20.64、20.92和0.47 ng·L-1,在所有的污水样品中均未检测出摇头丸和苯甲酰芽子碱,根据相关信息估算5种毒品的人均滥用量,并结合往年监测数据分析大连市这5种毒品的滥用趋势.甲基苯丙胺和海洛因滥用量均在2019年有上升趋势,2020大幅度下降,2021年基本保持不变;氯胺酮的滥用则一直处于较低水平.本研究为大连市实时监控毒品滥用情况提供科学依据,对防治毒品犯罪具有重要意义.  相似文献   
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