20世纪90年代以来主要气象灾害对我国粮食生产的影响与减灾对策

干旱、洪涝、风雹和低温四大类主要气象灾害已经成为限制我国粮食增产的主要障碍。近5年的统计结果表明，我国平均每年粮食受灾面积达0．52亿hm^2，粮食损失超过500亿kg。干旱是危害最大的灾种，每年因旱灾损失粮食占气象灾害损失粮食的57％。20世纪90年代以来旱灾的发生较以往大幅度加重。我国农业应该采取的减灾对策为：改善生态环境；加强农业基础设施建设；推广节水灌溉与旱作农业技术；加强农业减灾科学技术研究；完善农业防灾减灾体系；建立农业灾害保险与补贴机制。     

20世纪末期我国农地退化的经济损失估值

土地退化是自然过程与社会经济活动共同作用的现象。本文在分析中国农地退化基本态势的基础上，运用货币估值技术，对农地退化的各种损失进行了定量或半定量估算。估算表明：在1999年，中国由于农地退化所造成的经济损失达3268．1亿元，占当年GNP的4．1％，与1992年相比，经济损失占GNP的比重上升了1．5个百分点。     

建筑火灾风险综合评价对火灾保险费率影响的研究

保险人为了降低建筑火灾后巨额的损失赔付,需要在承保时对建筑物进行火灾风险评价,进而根据评价结果确定保险费率的大小.论文根据高层建筑火灾风险的模糊综合评价模型及评价结果所在的等级范围,提出并建立了保险费率浮动的关系方程式.最后应用此模型和关系式对一幢高层建筑的火灾风险进行了评价,得出其防火安全等级和费率的浮动值.研究结果表明,所建立的方法为保险人确定费率浮动提供了依据,并为承保前的检查、承保后的核查,提供了系统的技术手段.     

三面受火钢构件的温度数值计算

国内外铜结构抗火规范在钢构件的温升计算中,都忽略了构件与之相接触的混凝土板之间的热传递,虽然这样计算较为简单,但可能过高地估计了钢构件的温度.本文以三面受火工字型铜构件为研究对象,考虑构件实际换热条件的影响,建立了钢构件的热平衡方程,用数值计算方法分析钢构件的温度变化.计算结果表明本文计算温度与试验实测结果更为接近.     

Monitoring the impacts of urbanization and industrialization on the agricultural land and environment of the Torbali, Izmir region, Turkey

The aim of this research is to determine agricultural land loss and environmental pollution caused by industrialization and urban sprawl using the Geographical Information System (GIS) and Remote Sensing technique (RS). Remotely sensed data is the most powerful tool for monitoring land use changes and GIS is the best way to store and reproduce various kinds of integrated data. Considering the rapid increase of population the loss of fertile agricultural soils is a very dangerous situation for the future of the country. Thus, people are living in the cities in (with adverse) conditions of insufficient drinking water, infrastructure problems, inadequate landscape and many unsolved (extreme) environmental problems. During the last 36 years, unplanned urbanization and industrialization have led to the use of agricultural areas for non-agricultural purposes in the Torbali (Izmir) region, which has the most fertile soils of the Aegean Region. Within this study, a database was created on the parameters of land loss and environmental pollution by means of field observation, interpretation of satellite images (ASTER), aerial photos(1/25.000 scale), topographic map ,soil map, and 1/5.000 scale cadastral map. Results of previous researches and the archives of Torbali municipality were used as ancillary data. In the research, urbanization and industrialization of the town was studied by (using) GIS and RS between 1965 and 2001. Since 1965, 4.742.357 m² agricultural land, mostly of first and second land use capability classes, has been lost due to unplanned urban and industrial developments. Urbanization and industrialization involved an area of which 58% was being used as irrigated lands, 25 % rain feed (rain fed lands)and 17 % for olive growing.     

道路交通事故死亡者家属精神损失改进模型

针对道路交通事故死亡者家属的精神损失具有外延明确而内涵不明确的特点,将其作为一个灰色系统来研究,应用投入产出理论、人力资本投资理论和灰色理论,在已有计算模型的基础上,以时间投入、健康投入和教育投入为指标,建立了计算道路交通事故死亡者家属精神损失的改进模型。在确定灰色局势白化值、不同年龄段有效余生、投入产出比例系数与精神损失分配系数的基础上,给出了家属精神损失与道路交通事故死亡者健康等级、受教育程度、年龄分布的量化关系。由于该模型考虑了道路交通事故死亡者的教育投入因素,因此,与已有模型相比,笔者所提出的计算模型更能真实全面地反映道路交通事故给死亡者家属带来的精神损失。     

地板送风系统室内可吸入颗粒物沉降特性的试验研究

分析地板送风系统停机后影响室内可吸入颗粒物浓度变化的因素,建立颗粒物浓度的沉降模型并求出分析解,得出颗粒物浓度随时间的变化规律.通过颗粒物浓度的沉降模型计算颗粒物的沉降损失率和沉降速度.结果表明,当室内颗粒物的粒径大于1 μm时,其沉降损失率与粒径呈线性正相关; 粒径小于1 μm时,其沉降损失率和衰减率低于前者,但沉降稳定后的颗粒物浓度远大于前者.研究进一步证明了大粒径颗粒物的沉降主要由重力决定而小粒径的由布朗扩散力决定.     

Occupational noise exposure and hearing loss among pulse processing workers

Occupational noise exposure and noise-induced hearing loss (NIHL) has been recognised as a problem among workers in Indian industries. The major industries in India are based on the processing of agricultural products. There are appreciable numbers of pulse processing units spread throughout the country. The purpose of this study was to determine the prevalence of hearing loss among pulse processing workers. As a part of hearing protection intervention, audiometric tests were conducted at the binaural low (250–1,500 Hz), the binaural mid (1,500–4,000 Hz) and the binaural high (3,000–8,000 Hz) frequency averages. The prevalence of hearing loss was determined based on hearing threshold levels (HTLs) with a low fence of 25 dB. Over 50% of pulse processing workers (dana bazaar and dal mill) showed hearing loss in the noise-sensitive higher (binaural mid and high) frequencies. The rate of hearing loss was particularly high among workers in the dal mill. The analyses show a higher risk of prevalence of hearing loss among the dal mill workers compared to the workers associated with the grain preprocessing activities. The study shows alarming signals of NIHL, especially in the dal mill workers. The occupational exposure to noise could be minimised by efficient control measures through engineering controls, administrative controls and the use of personal protective devices. Applications of engineering and/or administrative controls are frequently not feasible in developing countries for technical and financial reasons. A complete hearing conservation programme, including training, audiometry and the use of hearing protection devices, is the most feasible method for the protection of industrial workers from prevailing noise in workplace environments in the developing countries.     

Assessing the Effectiveness of a Constructed Arctic Stream Using Multiple Biological Attributes

Objective assessment of habitat compensation is a central yet challenging issue for restoration ecologists. In 1997, a 3.4-km stream channel, designed to divert water around an open pit diamond mine, was excavated in the Barrenlands region of the Canadian Arctic to create productive stream habitat. We evaluated the initial success of this compensation program by comparing multiple biological attributes of the constructed stream during its first three years to those of natural reference streams in the area. The riparian zone of the constructed stream was largely devoid of vegetation throughout the period, in contrast to the densely vegetated zones of reference streams. The constructed stream also contained lower amounts of woody debris, coarse particulate organic matter (CPOM), and epilithon; had lower coverage by macrophytes and bryophytes; and processed leaf litter at a lower rate than reference streams. Species richness and densities of macroinvertebrates were consistently lower in the constructed stream compared to natural streams. This contributed to differences in macroinvertebrate assemblage structure throughout the period, although assemblages showed some convergence by year 3. The effectiveness of the constructed stream to emulate natural streams varied somewhat depending on the biological attribute being evaluated. Assessments based on individual attributes showed that minimal to moderate levels of similarity between the constructed stream and natural streams were achieved. A collective assessment of all biological and ecosystem attributes suggested that the constructed stream was not a good surrogate for natural streams during these first years. Additional time would be required before many characteristics of the constructed stream would resemble those of reference streams. Because initial efforts to improve fish habitat in the constructed stream focused on physical structures (e.g., weirs, vanes, rock, groins), ecological factors limiting fish growth were not considered and likely constrained success. We suggest that a greater focus on organic characteristics and vegetation within the stream and its riparian zone could have accelerated compensation. The addition of woody debris and CPOM, combined with planting of shrubs and herbs along the stream, should provide a source of allochthonous matter for the biotic community while large cobble and boulders should improve the physical stability of stream system, protecting its organic components.     

地震灾害损失评估

回顾了我国地震灾害损失评估的发展与现状,介绍了地震灾害损失评估的内容、方法和步骤,探讨了地震灾害损失评估中需要进一步研究的若干问题。