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521.
文中分析了在区域城市化水平初级阶段选择以生活服务基础性第三产业,在加速发展阶段选择生产服务性行业,在城市化稳定发展阶段,选择新兴技术服务行业不断升级的产业发展模式。本文以江苏省吴县市、邗江县、邳州市三个不同经济水平的地区为例做了详细分析。  相似文献   
522.
污染损失与环境效益分析   总被引:8,自引:0,他引:8  
污染损失是在某一污染状况下,环境资源使用者因环境污染所遭受的经济损失,包括损害费用和防护费用。污染损失不只与环境质量有关,也与环境资源使用量有关。以水污染为例,通过江苏某区水污损失估算结果,经回归分析,评价了该区“七五”期间水环境投入的效益。  相似文献   
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524.
In order to improve the hydraulic impact resistance of the polyvinyl alcohol (PVA) hydrogel as microorganism immobilization carrier and meet the requirements of long-time aeration of sewage treatment, the toughening PVA hydrogel beads were prepared by co-crosslinking with polyoxypropylene triol (PPG) through the boric acid (H3BO3)-chemical crosslinking method. It was found that PPG could increase the consumption of H3BO3, participated and accelerated the crosslinking reaction of PVA, and the pore size of the surface layer and core layer of the hydrogel beads can be controlled. With increasing PPG content, the shear storage modulus (G’) and the effective network density (νe) increased first, reached maximum in presence of 2 wt% PPG, and decreased afterwards. A relatively low content of PPG could promote the formation of relatively uniform and dense network structure in PVA hydrogel, resulting in an improvement of the mechanical property and long-term hydraulic stability of the gel beads. By addition of PPG, the capillary water absorption capacity of PVA hydrogel can be enhanced and the high permeability can be kept well. When applying in waste water treatment, the value of the oxygen uptake rate (OUR) and COD removal rate of the PVA hydrogel immobilized with activated sludge had no obvious difference with addition of PPG, and a high microbial activity can be maintained.  相似文献   
525.
Dai, Zhaohua, Carl C. Trettin, Changsheng Li, Devendra M. Amatya, Ge Sun, and Harbin Li, 2010. Sensitivity of Streamflow and Water Table Depth to Potential Climatic Variability in a Coastal Forested Watershed. Journal of the American Water Resources Association (JAWRA) 1–13. DOI: 10.1111/j.1752-1688.2010.00474.x Abstract: A physically based distributed hydrological model, MIKE SHE, was used to evaluate the effects of altered temperature and precipitation regimes on the streamflow and water table in a forested watershed on the southeastern Atlantic coastal plain. The model calibration and validation against both streamflow and water table depth showed that the MIKE SHE was applicable for predicting the streamflow and water table dynamics for this watershed with an acceptable model efficiency (E > 0.5 for daily streamflow and >0.75 for monthly streamflow). The simulation results from changing temperature and precipitation scenarios indicate that climate change influences both streamflow and water table in the forested watershed. Compared to current climate conditions, the annual average streamflow increased or decreased by 2.4% with one percentage increase or decrease in precipitation; a quadratic polynomial relationship between changes in water table depth (cm) and precipitation (%) was found. The annual average water table depth and annual average streamflow linearly decreased with an increase in temperature within the range of temperature change scenarios (0-6°C). The simulation results from the potential climate change scenarios indicate that future climate change will substantially impact the hydrological regime of upland and wetland forests on the coastal plain with corresponding implications to altered ecosystem functions that are dependent on water.  相似文献   
526.
    
Although widely explored in many studies, how and why combined top management team (TMT) and corporate characteristics affect environmental information disclosures (EID) are still lacking clarity. This study uses both fuzzy-set qualitative comparative analysis and necessary condition analysis to reconcile the inconclusive results concerning the configurational effects of these characteristics on EID and to validate the robustness. From a sample of listed construction engineering corporates during the 2014–2018 period, the high EID level is associated with several complex configurations that contain the core characteristics such as corporate ownership and size, whereas the low EID level is related to the configurations including TMT salary and corporate profitability. The findings support the four tenets of equifinality, asymmetry, complexity, and causal asymmetry in complexity theory. Our results capture the complex non-linear effects of TMT and corporate characteristics and shed new light on environmental disclosure management for corporate sustainable development.  相似文献   
527.
    
Water resource management is becoming increasingly challenging in northern China because of the rapid increase in water demand and decline in water supply due to climate change. We provide a case study demonstrating the importance of integrated watershed management in sustaining water resources in Chifeng City, northern China. We examine the consequences of various climate change scenarios and adaptive management options on water supply by integrating the Soil and Water Assessment Tool and Water Evaluation and Planning models. We show how integrated modeling is useful in projecting the likely effects of management options using limited information. Our study indicates that constructing more reservoirs can alleviate the current water shortage and groundwater depletion problems. However, this option is not necessarily the most effective measure to solve water supply problems; instead, improving irrigation efficiency and changing cropping structure may be more effective. Furthermore, measures to increase water supply have limited effects on water availability under a continuous drought and a dry‐and‐warm climate scenario. We conclude that the combined measure of reducing water demand and increasing supply is the most effective and practical solution for the water shortage problems in the study area.  相似文献   
528.
风幕集尘风机及其短路流场的数学模型研究   总被引:4,自引:1,他引:3  
应用风幕集尘技术,推出一种新型通风机——风幕集尘风机;介绍其构造及应用;提出短路流场理论,根据流场叠加原理,建立了流场数学模型.为粉尘环境的治理工程提供了一种新兴的高效技术产品.  相似文献   
529.
为深入研究闽江口富营养化机制,于1985—2021年在闽江入海断面开展了水质监测。采用结合局部加权回归散点平滑法(LOWESS)的季节性肯达尔检验(SK检验)对断面溶解无机氮(DIN)及其各组分浓度变化趋势进行分析,同时结合水文资料对入海通量进行估算。结果表明:DIN浓度范围为0.728~3.140 mg/L,在37年间整体呈上升趋势,但不显著。各组分中NO2-N和NH3-N浓度分别呈显著和极显著下降趋势,而NO3-N浓度呈极显著上升趋势。DIN组分中NO2-N和NH3-N比重不断减小,而NO3-N比重不断增大,目前已成为DIN的主要组成部分。DIN入海通量范围为3.59×104~14.85×104 t,在37年间缓慢增加,其各组分入海通量长期变化趋势同浓度变化类似。从长期来看,DIN及其各组分浓度的变化趋势主要受流域环境变化及下游福州市含氮废水排放影响,而在短期则受台风、降水等一些突发环境事件的影响较大。  相似文献   
530.
发达国家和地区在20世纪80年代陆续建立化学物质基础信息报告或调查制度,通过企业报告或调查的方式,全面收集化学物质生产、使用、排放等数据,为开展化学物质环境风险评估提供广泛和基础的数据来源,同时为制订有毒有害化学品环境风险管控措施提供数据支持。韩国是较早开展化学品调查且经验比较丰富的国家之一,通过修订完善韩国化学品管理法规体系和管理制度,建立化学品调查统计制度。借鉴韩国开展化学品调查的工作经验和做法,可为我国开展化学物质环境信息调查和数据收集提供重要的参考。  相似文献   
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