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91.
Sequence functions were used to construct a simulation model of the long-term population dynamics of the bank vole in Karelia. The mechanisms of population reproduction control affect the population size if it is greater than 1 and 4 ind./100 trap-days in spring and autumn, respectively. 相似文献
92.
Western China has lagged a lot in terms of industrial structure and economic development,compared with the national average.And China announced its target of CO_2 emission reduction,i.e.by 2020,CO_2 emission per GDP will drop by40-45%compared with 2005.The target will be incorporated into China's long-term industrial planning.Against this background,this paper will make a comprehensive examination of the industrial development of Western China,aiming to discover a green and compatible way.First,we analyze the spatiotemporal evolution of regional industrial structure for the period 2000-2010.Second,we try to discover the industrial structure optimization path for Western China by employing the Vector Auto Regression model.Lastly,we try to provide some advice and suggestions for further industrial development in Western China.Our examination shows that further industrial development in Western China should pay full attention to resource conservation and recycling,and develop on a green and compatible path. 相似文献
93.
In this paper deposition rate coefficients for unattached and attached radon progeny were estimated according to a particle deposition model for turbulent indoor airflow described by Zhao and Wu [2006. Modeling particle deposition from fully developed turbulent flow in ventilation duct. Atmos. Environ. 40, 457–466]. The parameter which characterizes turbulent indoor airflow in this model is friction velocity, u*. Indoor ventilation changes indoor airflow and friction velocity and influences deposition rate coefficients. Correlation between deposition and ventilation rate coefficients in the room was determined. It was shown that deposition rate coefficient increases with ventilation rate coefficient and that these parameters of the Jacobi room model cannot be assumed to be independent. The values of deposition rate coefficients were presented as functions of friction velocity and ventilation rate coefficient. If ventilation rate coefficient varies from 0.1 up to 1 h−1, deposition rate coefficients for unattached and attached fractions were estimated to be in the range 3–110 h−1 and 0.015–0.35 h−1, respectively. 相似文献
94.
采用问卷调查、层次分析、专家咨询等方法,构建了综合考虑经济效益、产品品质和环境效益3个方面共包括12项指标的芹菜面源污染防治种植模式综合效益评估指标体系,应用该指标体系在巢湖流域开展了由不同施肥方式、是否施用松土促根剂和生物基膜等单项技术组合的不同面源污染防治种植模式效益评估的实证研究。结果表明:经济效益表现最好的是减量施肥+松土促根剂模式,产品品质效益最优的是减量施肥模式,环境效益最好的是有机无机肥混施+松土促根剂+生物基膜模式,综合效益最好的是有机无机肥混施+松土促根剂+生物基膜模式。采用减量施肥和有机无机肥混施模式,同时配合松土促根剂和生物基膜的技术组合可有效提高综合效益。 相似文献
95.
为解决传统养殖中养殖尾水的环境污染问题,促进池塘养殖可持续发展,基于新建的集装箱式循环水养殖系统,构建了三级养殖尾水净化塘水生态系统模型,对池塘水质、浮游植物及水生动物生物量以及池塘生态系统的演变进行了为期6个月的模拟预测,并设置添加沉水植物和添加低密度滤食性鱼类2种情景模拟。结果表明:水质模拟值的变化趋势与实测值基本一致,模拟值与实测值的平均相对误差为4.98% ~ 23.37%;模拟预测的设定条件下和模拟时段中,池塘生态系统的结构趋于稳定,形成以绿藻为主的藻类群落、以摇蚊和桡足类为主的水生动物群落;在尾水净化塘中,添加沉水植物对氮磷去除效果不明显,但对增加水体中溶解氧质量浓度作用明显,3个池塘溶解氧变化率最大值分别为23.11%、45.39%和77.90%;添加低密度滤食性鱼类有助于浮游植物的生长,3个池塘硅藻生物量的最大增幅为89.80%、47.22%和22.06%,绿藻生物量的最大增幅为76.95%、54.05%和23.29%,蓝藻生物量的最大增幅为45.99%、33.37%和20.30%。综上所述,基于AQUATOX构建串联的尾水净化塘水生态系统模型并模拟培植沉水植物和添加低密度滤食性鱼类的生物处理方法,不仅能够为管理者调整喂养结构提供借鉴与帮助,也可用于调控水生态系统组分,有利于水生态系统功能的恢复和平衡。本研究结果可为管理集装箱式循环水养殖模式的喂养结构、构建尾水净化塘生态系统、改进其他利用生物处理技术处理养殖尾水的养殖模式提供参考。 相似文献
96.
传统水质模拟预测模型对突发水污染事故事发地的水文、水下地形等资料要求较高,在缺乏相应资料时会影响对水污染事故的可靠预测和预警。为解决问题,亟需建立在应急条件下能快速预测预警的简化水质模型。以传统一维水质模型为基础,通过人工测量河流沿程流速,自动插值获得流场以替代模型中对流场的求解,再求解一维对流扩散方程,以此获得简化的一维水质模拟预测模型。模拟计算结果表明,相对于传统水质模型,简化后一维水质预警模型可快速准确地预测突发水污染事故后污染态势。 相似文献
97.
以浦阳江流域(浦江县段)为研究区,从流域面源污染空间特征入手,提出浦阳江流域岸边带建设的重点区域。采用DPeRS面源污染负荷估算模型,具体分析了2018年浦阳江流域面源污染负荷空间分布特征,并采用面向对象方法提取了岸线和河流生态缓冲带土地覆盖类型,以汇水区为单元,结合面源污染估算结果识别了浦阳江流域河流生态缓冲带重点区。结果表明:浦阳江流域中部和中北部地区面源污染排放负荷较高,面源污染入河负荷高值区主要集中于中下游地区;该流域31个汇水区中,TN和NH4+-N重点汇水区有17个,主要分布在流域的中部和东北部;TP和COD重点汇水区有12个,集中分布于流域中部;浦阳江流域河流生态缓冲带范围内,植被类型和非植被类型面积占比分别为65.49%和34.51%,其中耕地面积占比29.36%,建筑用地占比11.89%;综合浦阳江流域面源污染重点汇水区和河流生态缓冲带现状遥感提取结果,筛选出的重点区包括下游地区的7号汇水区和中游地区的18~25号汇水区所在的河流生态缓冲带。今后,可针对其重点区域设计生态防护工程,也应结合源头减量、过程拦截、末端消纳与资源循环利用的防控策略,综合削减面源污染物入河量。 相似文献
98.
Advancements in technology are inextricably bound to our society and the natural environment. However, how the development process of a technology system interacts with both remains unclear. We propose a process model to understand the complex dynamics among technology, society, and the environment via seven interactive elements: technologies, actors, receiving bodies, natural contexts, social contexts, temporal–spatial contexts, and outcomes. The model was applied to agricultural and water technology development in China from 8000 bc to 1911 ad. Our findings show that these elements did not play equally important roles in different periods of the development in ancient China, with social contexts most dominating during the earlier periods and both social and environmental concerns arising towards the later periods. The proposed model, by identifying the elements in the technology development that should be strengthened, can act as an analysis device to assist in reconfiguring a more sustainable socio-technological system.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01424-7) contains supplementary material, which is available to authorized users. 相似文献
99.
Kentaro Murano Hitoshi Mukai Shiro Hatakeyama Eun Suk Jang Itsushi Uno 《Atmospheric environment (Oxford, England : 1994)》2000,34(29-30)
Observations of air pollutants were conducted in remote Japanese islands (Oki Island and Okinawa Island) in early spring to clarify the extent of trans-boundary air pollution from the Asian continent. A three-dimensional Eulerian model calculation, which included parameters on emission, transport and transformation of sulfur oxides, nitrogen oxides and ammonia, was performed to compile sulfate isosurface concentrations over the observational sites. Concentrations of non-sea-salt sulfate (nss-SO42−) of greater than 10 μg m−3 were observed at Oki after the northeastward passage of low-pressure systems in the Sea of Japan. At these times, the weather showed a typical winter pattern and air pollutants over China were transported southeastward to Japan with the northwesterly wind. The model calculation reproduced the observed variations of nss-SO42− concentration well, except for one case in which the model calculation could not reproduce the extremely low nss-SO42− concentration observed on 8 March. In Hedo (Okinawa Island), we observed long-lasting (3 days) medium concentrations of nss-SO42− (approximately 5 μg m−3). Although the model reproduced these observed medium concentrations well, in general the observed results were reproduced better for Oki than for Hedo. Under the synoptic weather conditions of early spring, high concentrations of nss-sulfate were sometimes transported to these remote Japanese islands from areas of continental Asia with a strong outflow of air pollutants. 相似文献
100.
本文综述了活性污泥模型从基于Monod方程的稳态模型到以ASM1、ASM2、ASM3为代表的动态模型的发展过程 ,介绍了各代表性模型的特点并对当前典型的活性污泥工艺软件作了评述 ,提出其研究方向及发展趋势 相似文献