RS、GIS在内陆湖泊水质研究中的应用

:遥感 (RS)、地理信息系统 (GIS)技术的综合应用在许多研究领域广泛推广并日渐成熟 ,表现出广阔的发展前景。将 RS、GIS相结合 ,综合应用于内陆湖泊水质的监测和分析 ,充分体现了其快速、经济、高效的强大优势。本文首先回顾了一般监测方法的特点及局限性 ,主要讨论了 RS、GIS的特点及在内陆湖泊监测和分析中的优势所在。最后提出了此领域的发展方向展望     

乡镇环境保护的“角直模式”

本文分析了江苏省角直镇乡镇经济腾飞与环境保护协调同步的发展过程,总结出了“统一规划、合理布局、集中控制、全面管理、环境保护与经济建设协调发展”的“角直模式”,并就模式的优缺点作了一定程度的探讨.     

铁路运输安全事故灰色预测方法研究

近年来 ,我国铁路运输发展迅猛 ,尤其是列车运行多次提速 ,列车运行密度加大 ,对铁路运输安全管理不断提出了新的要求。依靠科技进步 ,尽量防止或减少安全事故的发生 ,要应用安全信息技术 ,使安全管理人员对铁路运输安全现状及未来事故发展趋势有所了解 ,提高安全防范意识及事故处理能力 ,同时还要不断提高员工的安全意识和安全文化素质 ,这些方法对于提高安全管理水平 ,降低事故的发生 ,保护人民的生命安全与健康具有重要意义。铁路运输安全事故预测技术就可很好解决上述问题。笔者应用灰色预测理论 ,建立了铁路运输安全事故预测模型 ,开发了安全事故预测软件系统 ,并以某铁路运输企业为例 ,介绍了研制的灰色预测系统软件的应用效果     

铅芯橡胶支座等效线性分析模型参数的研究

针对目前铅芯橡胶支座等效线性分析模型动力参数选取不够合理的现状 ,笔者通过对铅芯橡胶支座水平动态试验分析 ,系统研究了铅芯橡胶支座等效线性分析模型参数与其几何结构及外加动力荷载特性的关系。研究结果表明 :铅芯橡胶支座等效线性分析模型参数 (水平耗能、等效刚度及等效阻尼比 )主要由其本身的几何构造及组成材料决定 ,且在往复加、卸载循环过程中具有较好的稳定性。笔者对试验数据进行数学统计分析 ,归纳出一些经验公式 ,为其等效线性化动力分析模型参数的合理选取提供了计算方法 ,从而提高其动力分析结果的安全性。     

一个研究街道峡谷流场及浓度场特征的三维数值模式

目前，研究街道峡谷内流场及机动车排放污染物的扩散行为特征所采用的主要方法为：采用野外测试法和物理模拟法，而采用三维数值模拟方法研究此问题的工作很少。本文创建了一个研究微尺度街道峡谷内流场及机动车排放污染物扩散特征的三维数值模式，即首次采用伪不定常方法，利用K——E闭合方案，建立了一个模拟城市街道峡谷内流场及污染物扩散特征与街道峡谷风场、街道几何结构及两侧建筑物高度对称性之间的复杂关系的三维数值模式。经过与实际监测资料及风洞实验对比，结果表明此三维模式具有较好的模拟精度，能够很好模拟峡谷内的风场及街谷几何结构对街道峡谷内流场及浓度场特征的影响，有很强的实用性。     

农业非点源模型--AGNPS概述

非点源污染在国内外已越来越受到关注，其中农业非点源又占相当大的份额。由于非点源污染产生机制的特殊性。导致实地调查和试验研究不易实行。故而数学模型方法在这一领域尤其能够体现出它的优点，对它的研究也受到了学术界越来越多的重视。目前，国外已开发出了大量的非点源数学模型，而其中A3NPS模型是应用较为广泛者之一，并已在我国得到了应用。基于此，文中介绍了AGNPS模型的基本结构，主要包括水文、侵蚀和化学污染物的迁移三部分。自从该模型被建立以来，国外已对它进行了大量的研究，本文从研究最多的几个方面进行了讨论，即计算网格的优化、模型输入输出与GIS的结合以及模型的风险性等，以期为在我国的具体应用提供一定的参考。     

Possible Utilization of Silica Gel Sludge for the Removal of Phenol from Aqueous Solutions: Laboratory Studies

This paper discusses the adsorption capacity of silica gel sludge for phenol removal from aqueous solution. Kinetic experiments showed that phenol adsorption was completed after 2 h. Adsorption isotherms were measured for phenol from aqueous solution onto silica gel sludge under various pHs and temperatures. Results showed that the adsorption capacities for phenol was increased as pH decreased from 6.5 to 2. Temperature also was found to affect the adsorption isotherm. As temperature increases from 30 to 50°C, the adsorption capacity increases. The adsorption equilibrium of phenol on silica gel sludge was described by the linear Freundlich and Langmuir models. Furthermore, results showed that the isotherm parameters fit both linearized Langmuir and Freundlich adsorption isotherms. The Freundlich and Langmuir parameters at optimum pH was found as K _f=2.89, 1/n=0.23 and K _d=22.0, q _m=7.98, respectively. Whereas, for those at optimum temperature it was observed as K _f=2.87, 1/n=0.16 and K _d=20.93, q _m=7.91, respectively.     

What do economic simulations tell us? Recent mergers in the iron ore industry

This paper investigates the European Commission's decision to allow a merger between two Brazilian iron ore mining companies, CVRD and Caemi, using data on the Direct Reduced Iron pellet market. By using a simulation model, we can directly simulate the total welfare effects from the merger and hence evaluate the merger from a new perspective. The results from our simulations suggest that the welfare effects are negative from the merger between CVRD and Caemi, which supports the conclusion drawn by the European Commission decision. By performing different simulations between hypothetical merger candidates, our results show that only mergers between small candidates have the potential to be welfare enhancing.     

避雷针保护范围验算数学模型的确定

主要针对现有国家标准中避雷针保护范围确定的问题 ,即多是给予形状上的描述 ,而在实际设计或验算过程中通常计算量很大且重复工作多 ,笔者为应对上述的问题 ,提出了新的思路和新方法 ,建立了避雷针保护范围计算的数学模型 ,且编制了相应软件。     

Annual and Diurnal Wind Patterns in the City of São Paulo

The major topographic, mesoscale, and urban influences on the wind patterns of the City of São Paulo are characterized using one year of surface wind velocity data observed at 11 surface stations within its urban limits. The data was used to study the diurnal and annual variations of wind velocity and horizontal wind divergence within the city. Results showed that the circulation over the investigated area is dominated by three major factors: sea breeze; mountain-valley circulations; and urban effects, such as roughness, building-barrier, and urban heat island. The sea breeze was found to be the dominant feature of the monthly-averaged diurnal variation of São Paulo surface winds during the eight warmest months of the year. The sea breeze front induces a velocity minimum at the time of its passage and a post-frontal afternoon velocity maximum. Mountain-valley thermal effects on the flow can be seen in the temporal divergence/convergence patterns. These thermal effects tend to be more important during colder months, at night, and when the wind velocities are low. Nighttime downslope convergent flows are present over the city during winter and spring and daytime upslope divergent flows are present over the city during summer months.