城市声环境舒适性服务功能价值分析

与传统的正向思维方式相反,根据声环境系统"无形"的特点,提出基于污染损失率模型的声环境舒适性服务功能价值研究方法,并以大连市1996年声环境系统的服务功能价值计算为例进行说明.案例分析的结果表明,大连市1996年声环境舒适性服务功能价值为1.88×108元,相当于大连市当年GDP的0.25%,其中28.37%的服务功能价值因污染受到损失.     

Ozone distribution in central Italy and its effect on crop productivity

The focus of the present study was to assess the ozone levels in a typical area of the Mediterranean basin, viz. Tuscany (central Italy). Eighty-thousand hourly mean ozone concentrations were recorded by 10 automatic analysers in the districts of Florence, Pisa, Lucca and Prato, from May to September 1995 to 1997. The highest daily mean concentrations were reached in Florence, with a maximum hourly average of 197 ppb. In Lucca and Pisa, the peaks were close to 100 ppb. Data from Prato were much lower. Long-term critical levels for vegetation, as set by United Nations Economic Commission for Europe (UNECE), were constantly exceeded in Florence and Pisa, occasionally in Lucca, never in Prato. The results were used to fit exposure/yield response relationships proposed by UNECE and US National Crop Loss Assessment Network for some important crops. The estimated yield losses varied in Florence from 8% for corn and alfalfa to 27% for soybean, in Pisa from 5% for corn to 24% for soybean, in Lucca from 3% for corn to 17% for soybean. A preliminary economic estimate for corn, wheat, barley, soybean, tomato and alfalfa, calculated annual damage to be 4.6 M Euro in Florence, 0.5 M Euro in Lucca and 3 M Euro in Pisa. The picture must be regarded as only partial, as exposure/yield response relationships for important Italian crops (such as grapevine and vegetables) are not available.     

Effects of acid deposition on terrestrial ecosystems and their rehabilitation strategies in China

ＩｎｔｒｏｄｕｃｔｉｏｎＣｈｉｎａｉｓｏｎｅｏｆｔｈｅｌａｒｇｅｓｔｃｏｕｎｔｒｉｅｓｏｆｃｏａｌｃｏｍｂｕｓｔｉｏｎ ,ｗｈｉｃｈａｃｃｏｕｎｔｆｏｒ 75%ｏｆｔｏｔａｌｅｎｅｒｇｙｃｏｎｓｕｍｐｔｉｏｎ .Ｃｏａｌｃｏｍｂｕｓｔｉｏｎｉｎｃｒｅａｓｅｄｆｒｏｍ 0 .6ｂｉｌｌｉｏｎｔｏｎｓｉｎ 1 980ｔｏ 1 .2 8ｂｉｌｌｉｏｎｔｏｎｓｉｎ 1 995,ａｎｄｗｏｕｌｄｒｅａｃｈｔｏ 1 .45ｂｉｌｌｉｏｎｔｏｎｓｉｎ 2 0 0 0 .ＥｍｉｓｓｉｏｎｏｆＳＯ2 ｉｎｃｒｅａｓｅｄｗｉｔｈｉｎｃｒｅａｓｉｎｇｃｏａｌｃｏｎｓ…     

海滨景观环境污染的经济损失估算

本文应用调查评价法理论，对烟台芝罘湾海滨景观遭受环境污染的程度，进行了经济损失估算。调查问卷中设计了一些问题，其结果给出了不同人群的支付愿望和经济损失价值。     

便携式气相色谱仪在VOCs污染源监测中的应用

便携式气相色谱仪（Portable GC）是一种能在野外现场完成对VOCs气体进行分析测试的新型气相色谱仪，该仪器完全避免VOCs监测中的样品的保存问题。通过对这种仪器性能与操作，以及用针筒、塑料袋采集3苯（苯、甲苯、二甲苯）的采样评价实验，探讨了便携式气相色谱仪在VOCs污染源监测中的应用。     

Avian Community Response to Lowland Tropical Rainforest Isolation: 40 Years of Change at La Selva Biological Station, Costa Rica

Abstract:  Since 1960, most of the forest surrounding the La Selva Biological Station, an intensively studied tropical research facility in Costa Rica, has been converted to agricultural uses. We used quantitative censuses and analysis of previously published categorical abundances to assess changes in the bird community, and we evaluated potential causes of species-specific changes by assessing their association with habitat, diet, participation in mixed-species flocks, and nest type. Approximately the same percentage of species increased as decreased in abundance from 1960 to 1999 (10–20% of all species, depending on method of assessment). Diet was the single most important trait associated with declining species. At least 50% of the species that declined have insectivorous diets. Use of forest habitat and participation in mixed-species flocks were also significant factors associated with declines, but nest type was unrelated to change in abundance. The species that increased in abundance tended to occur in open habitats and have omnivorous diets. These results reinforce the importance of several population risk factors associated with tropical understory insectivory and mixed-species flocking: patchy spatial distribution, low population density, large home range, and dietary specialization. La Selva's protected area (1611 ha), despite a forested connection on one boundary with a higher elevation national park, is apparently too small to maintain at least one major guild (understory insectivores). This first quantitative assessment of bird community change at La Selva highlights the need to intensify study of the mechanisms and consequences of biological diversity change in tropical forest fragments.     

Demographic Responses by Birds to Forest Fragmentation

Abstract:  Despite intensive recent research on the effects of habitat loss and fragmentation on bird populations, our understanding of underlying demographic causes of population declines is limited. We reviewed avian demography in relation to habitat fragmentation. Then, through a meta-analysis, we compared specific demographic responses by forest birds to habitat fragmentation, providing a general perspective of factors that make some species and populations more vulnerable to fragmentation than others. We obtained data from the scientific literature on dispersal, survival, fecundity, and nesting success of birds. Birds were divided into subgroups on the basis of region, nest site, biogeographical history, and migration strategy. Species most sensitive to fragmentation were ground- or open-nesters nesting in shrubs or trees. Residents were equally sensitive to fragmentation in the Nearctic and Palearctic regions, but Nearctic migrants were more sensitive than Palearctic migrants. Old World species were less sensitive than New World species, which was predicted based on the history of forest fragmentation on these two continents. Pairing success was the variable most associated with fragmentation, suggesting an important role of dispersal. Fledgling number or condition, timing of nesting, and clutch size were not associated with sensitivity to fragmentation, suggesting that negative fragmentation effects on birds do not generally result from diminished food resources with increasing level of fragmentation. Future studies on demographic responses of birds to habitat fragmentation would be more effective if based on a combination of measures that can distinguish among the demographic mechanisms underlying population changes related to habitat fragmentation.     

Occupational noise exposure and hearing defects among sawmill workers in the south of Thailand

The aim of this study was to investigate occupational noise exposure and hearing defects among sawmill workers in the south of Thailand. Seven hundred sawmill workers participated, of which 335 (47.9%) were male. The mean age of the sawmill workers was 33.5 years (SD 10.2), and more than 60% were <35 years old; 75.1% of the workers had less than 5 years of work experience. Only about one in four workers (25%) had been trained in use of personal protective equipment (PPE), and half of the participants never or rarely wore PPE while working. The prevalence rate of noise-induced hearing loss (NIHL) was 22.8% (N?=?42). Male workers had significantly higher risk than female workers (odds ratio [OR]?=?2.21). Workers aged older than 25 years had significantly higher risks for NIHL (OR?=?3.51–12.42) than workers younger than 25 years. Sawing workers had higher risk for NIHL than office workers (OR?=?3.07).     

氧化铁粒径对固体推进剂火焰特征参数影响的试验研究

针对5-氨基四氮唑/硝酸锶固体推进剂在实际应用中存在的推进剂火焰偏大、容易在灭火装置喷口处形成外喷火焰的问题,选用了微米氧化铁和纳米氧化铁作为催化剂,分别从火焰形态、质量损失速率、热释放速率、无量纲火焰高度模型几个角度开展研究,对比了两种不同粒径的氧化铁对5-氨基四氮唑/硝酸锶固体推进剂燃烧火焰的优化效果。根据燃烧试验结果,发现不论是富氧燃烧还是贫氧燃烧,在降低推进剂燃烧时的火焰高度方面,微米氧化铁均明显优于纳米氧化铁;在提高质量损失速率方面,微米氧化铁的加速效果也要优于纳米氧化铁。基于传统的液态燃料油池火发展的火焰高度预测模型,将无量纲火焰高度与热释放速率的分析关系应用到固体推进剂燃烧领域,考虑使用无量纲火焰高度的分析方法,对固体推进剂燃烧过程中的火焰高度进行预测,建立了5-氨基四氮唑/硝酸锶固体推进剂的无量纲火焰高度模型,发现不含氧化铁和含有氧化铁的5-氨基四氮唑/硝酸锶固体推进剂燃烧时的火焰高度与热释放速率的n次方成正比,该无量纲拟合可以对固体推进剂火焰高度进行预测。最终,得出了微米氧化铁比纳米氧化铁更适合作为催化剂被用于5-氨基四氮唑/硝酸锶推进剂中,有利于提高固体推进式灭火装置的灭火效果。     

特殊阻力与喷枪喷头结构合理设计

喷枪喷头的结构设计和加工质量可大幅度地影响射流质量和喷射效果。本文重点论述了合理结构设计对减少特殊阻力、提高喷头效率的影响。同时提出了减少特殊阻力的具体措施。这对提高射流的打击效果和工作效率大有稗益。