岩石断裂和破碎的分形研究

岩石断裂与破碎的研究一直是岩石力学的前沿领域,也是采矿、能源、水利、交通、地震等众多工程领域不可或缺的理论基础。本文系统介绍了将分形理论引进到岩石断裂和破碎研究的成果,其中包括岩石微观断裂、宏观裂纹动态扩展以及岩体破碎的块度分布,旨在从一个侧面反映分形理论在岩石力学中的应用,最后还给出了一个工程应用的例子。本文的部分结果曾发表于国际杂志上。     

Impact of the FTSE4Good Index on firm price: an event study

This paper examines whether corporate financial performance is affected by public endorsement of environmental and social performance. Event study methodology, which relies on the notion of market efficiency, is used to examine the relationship between positive and negative announcements and changes in share prices or daily returns. Inclusion in and deletion from the FTSE4Good UK Index is used as a proxy measure for good (poor) corporate social responsibility. The abnormal or unexpected daily returns associated with an event are calculated and their significance tested. The results show a trend towards positive and negative announcements having the expected effects on daily returns. But these movements are not significant and the data do not suggest that a firm's presence on the index brings it any significant financial return for signalling its corporate social responsibility.     

南京市快速城市化时期城市用地优化评价实证研究

我国已经进入快速城市化的关键时期。城市用地需求激增，城市空间变化剧烈。按照科学发展观的时代要求,正确评价城市土地的利用水平，促进区域城市的健康和谐发展，具有十分重要的意义。以南京市为例，总结了城市用地建设中存在的城乡失衡、耕地危机、功能削弱、效率降低等主要问题，并尝试建立土地利用优化评价模型，以综合判断在快速城市化阶段城市用地的集约化程度。通过对南京市的实证分析可见，在城市的迅速扩张中，城市用地的确存在集约水平波动的现象，而且不同指标呈现差异化发展趋势。21世纪的城市土地利用，由粗放到集约、由重量到重质、由紊乱到有序是必然选择。     

人口、资源与环境经济学教材比较研究

人口、资源与环境经济学是理论经济学下设立的一个二级学科。自1997年设立以来，很多学者对其学科体系进行了探索。出版了一些著作和教材。本文以现代课程与教学论的观点为指导．采用文献研究、比较分析、统计分析的方法．从教材现状、体系结构、内容、表现形式和手段等方面对国内外人口、资源与环境经济学教材进行了详细的比较研究，并在此基础上为新教材建设提出了建议。以期为国内相关教材的改进和完善提供参考依据。这些建议是：统一并完善教材体系；理论要联系实际．培养学生学习兴趣和解决实际问题能力；注重学科领域最新成果的运用。增强教材的时代性和科学性；注重表现形式和手段多样性，帮助读者理解抽象的经济理论。     

硝酸钙抑制底泥磷释放的模拟研究

在实验室模拟了硝酸钙对底泥磷释放的影响、环境效应及作用机制。结果表明,硝酸钙可有效降低孔隙水和上覆水中溶解活性磷(SRP)的浓度,且对于红枫湖底泥来说,抑制磷释放的硝酸钙Ca(NO3)2·4H2O最佳用量为187.5g/m2。实验表明硝酸钙的使用是安全的,既可保证上覆水中氨氮浓度满足III类水的要求,也不会造成水体重金属的污染。硝酸钙抑制底泥磷释放作用机制如下:1)硝酸钙在底泥脱氮微生物的作用下发生反硝化作用,在硝态氮被消耗的同时,溶解有机碳亦被氧化降解;2)硝酸钙将底泥中的Fe2+氧化为Fe3+,促使铁氧化物及氢氧化物的形成,最终使孔隙水及上覆水中SRP的浓度大幅降低。因此,硝酸钙可有效抑制底泥内源磷的释放,是一种高效的底泥内源磷释放原位钝化剂,可为湖泊底泥磷污染提供有效的治理手段。     

People matter: The importance of social capital in the co-management of natural resources

Co‐management involves the shared administration of natural resources by two or more parties. This study examines the role of social capital in the process of developing co‐management in three river corridors in Canada. Qualitative analysis reveals that social capital acts as a catalyst helping groups to progress through the stages of the co‐management process. Forms of social capital (bridging and bonding) are identified that advance and/or inhibit the development of co‐management. The article reaffirms the need to expand the institutional basis for natural resource management and provides empirical evidence that social capital plays a fundamental role in developing co‐management. In conclusion, the article suggests that resource agencies need to recognize the value of social capital and the necessity for government representatives to be informed of and practiced in these skills, if they are to engage meaningfully with the civilian population.     

Modelling of the location of vehicle recycling facilities: A case study in Poland

The technical progress causes that increasing number of used devices presents a threat for environment, particularly in the rural areas. It can be prevented by organizing a proper system of waste disposal. Currently, the most important problem to solve is recycling of vehicles. The key element for the improvement of the functioning of the recycling network in Poland is to redesign the system so that it will allow for a reduction of the total cost related to the vehicle recycling. This paper presents a modelling approach that could be used to establish one important part of the reverse logistics (RL) network for end-of-life vehicles (ELVs) by defining the optimum locations for dismantling facilities. The proposed modelling approach is illustrated using Mazovia province in Poland as an example. The optimization criteria for the location of the elements of the recycling network are the components of the total cost of the ELV's recycling. Due to high complexity of the model a genetic algorithm has been adapted for solving the model and getting a good solution in a reasonable run time. The criteria of optimization was cost of the following processes: transportation, storage, and dismantling of ELVs. The results of simulation proved that the transportation costs of parts and materials may amount to about 70%, and that the cost of dismantling may exceed 25% of the total cost of recycling. The obtained results confirmed that genetic algorithm method can be used effectively to location the ELV's dismantling facilities. The effect of changing the location of processing facilities on the location of dismantling stations was also studied. The developed model is universal and may be used to determine the locations of different kinds of facilities organized in a reverse recycling network.     

国内外石油化工行业事故预警预防管理对比研究

介绍了发达国家在事故调查、分析、研究、预警和预防管理方面的先进做法,对比分析了我国石油化工行业在这些方面存在的差距,提出了针对性的建议措施。     

不同波长和强度光照对水体汞还原的影响

采用室内模拟实验,探讨不同光波长、强度对HgCl2还原反应的影响,根据载气中Hg0的实时浓度跟踪HgCl2还原反应的过程,计算Hg0释放通量来进行汞光还原程度定性分析、动力学定量分析,并运用积分法和微分法确定反应级数.结果表明,Hg2+的还原量与光波长呈负相关、与光强度呈正相关,说明光子提供的能量对汞的光还原反应起关键性作用,汞还原率由光波长和强度共同决定,并且受溶液体积和载气流速影响;在各组实验中,载气中的Hg0浓度均表现为先上升再下降后趋于平稳的规律,Hg0浓度上升阶段的主要反应是Hg2+的还原反应和Hg0的释放,而下降阶段的主要反应是Hg0的释放;本研究中可见光下的汞还原反应为一级反应,UVA、UVB光照下的汞还原反应为二级反应,这与汞的配合物具有特定的光谱吸收带和实验用灯提供的光波范围有关.     

广西崇左市发展蔗糖循环经济研究

崇左市是全国最大的蔗糖生产和加工基地,被誉为“中国糖都”,甘蔗种植水平和制糖企业的生产技术水平位于广西前列,蔗糖循环经济初具规模.对崇左市发展蔗糖循环经济的基本条件、目标原则及发展途径进行系统分析,为政府加快发展蔗糖循环经济提出对策建议.