导气管管径对准好氧生物反应器填埋场碳氮污染物转化的影响

通过建立3个不同导气管管径(Ф25 mm,Ф50 mm,Ф75 mm)的准好氧生物反应器填埋场,探究了导气管管径对其碳氮污染物转化的影响.研究表明,准好氧生物反应器填埋场渗滤液总氮、氨氮、CODCr、TOC的降解均符合线性-指数复合模型,且当导气管管径由25 mm增大至50mm时,可明显提高其降解速率,分别由0.00323、0.00474、0.01177、0.0059 d-1提高至0.01921、0.02267、0.01617、0.01253 d-1;由50 mm进一步增大至75 mm时,渗滤液碳氮污染物的降解速率也有小幅提高.导气管管径的增大有利于填埋体内碳氮污染物的去除,由Ф25 mm增大至Ф50mm时,碳氮污染物去除率明显提高,且只有很少部分转移至液相中,同时氮污染物和碳污染物的气化率分别提高了33.42%和10.74%;进一步增大至Ф75 mm时,碳氮污染物去除率也有一定程度提高.导气管管径越大,固相中碳氮物质剩余率越低,液化率越低,气化率越高.     

温湿度应力对火工品金属桥带温度场影响的仿真与试验研究

目的 研究火工品换能元所用的金属桥带表面划痕等缺陷在温湿度应力作用下的扩展情况及其对火工品功能的影响.方法 设计温湿度为80℃/95％的双应力试验,采用形貌分析和红外热波等手段,结合仿真计算,研究温湿度应力对划痕尺寸的影响及其对换能元桥区温度场的影响规律.结果 金属桥带在温湿度应力的作用下,180 d的试验时间内,表面...     

Mutual Conversion of Land Use between Urban and Rural Area in the Process of Urbanization: A Case Study of Shandong Province

Abstract

Urbanization is one of the driving forces for the land use change in type and structure, and its prominent effect is to convert rural land to urban land. This paper takes Shandong Province as an example to analyze the current situation of the mutual conversion between the urban and rural areas from the aspects of the structure of land use, the decreasing tendency of the cultivated land, the changes of land use in urban and rural residential areas. It points out that cultivated land is converted to residential area land, industrial and/or mining area land. The relationship between the urban area land and the cultivated land is more direct; meanwhile, the changes of rural residential area lag behind obviously. The decrease of the cultivated land and the decline of soil quality will be the two difficult problems in the process of urbanization.     

转型期中国耕地非农化与土地退化的实证分析

改革开放以来．伴随着国民经济的快速发展．中国的耕地非农化速度也在不断加快。并由此产生了大量的社会和环境问题。本文从人类土地利用行为变化的角度提出了分析耕地非农化对土地退化影响的基本思路：然后基于这一思路．并结合对全国层面统计数据的计量分析．深入探讨了转型期中国的耕地非农化对土地退化的影响：研究表明由耕地非农化所引致的耕地开垦、耕地集约利用以及非农建设用地扩张等人们土地利用行为的变化会最终引起土地资源的退化：包括水土流失和土地沙化的加剧、土壤质量的退化以及土地污染的加剧等。     

变频调速技术在高炉出铁场除尘中的应用

介绍了变频调速技术，结合实例论述了出铁场除尘系统采用此技术的经济性，并与其他调节方式作了比较，证明其在技术上及经济上均较优越。     

MTO废催化剂SAPO-34的再生

采用干凝胶转化法对甲醇制烯烃(MTO)废催化剂SAPO-34进行再生,将SAPO-34分子筛晶化所需的硅、铝、磷原料同时作为黏结剂使用,经干凝胶转化制备出再生催化剂,并对催化剂进行了表征及MTO反应活性评价。表征结果显示,再生催化剂的晶体结构、微观形貌、粒径分布、孔结构、耐磨性及酸中心均得到了恢复与改善,磨损指数可达0.35%/h。实验结果表明:在催化剂加入量为1.0 g、进气中甲醇质量分数为95%、甲醇质量空速为3 h-1、反应温度为450℃、反应压力为常压的条件下,再生催化剂的甲醇转化率接近100%,双烯(乙烯和丙烯)选择性较废催化剂提高了约3百分点,可达87%以上;同时,再生催化剂的寿命也较废催化剂有了明显改善。     

O_2/CO_2半焦煤燃料N向NO转化规律试验研究

在立式管式炉燃烧试验装置上,O_2/CO_2燃烧条件下,对半焦煤在不同温度及氧气浓度对燃料N向NO转化规律进行研究。结果表明:ρ(O_2)∶ρ(CO_2)=1∶4燃烧气氛,1 000℃时,NO生成曲线表现出双峰结构趋势,温度升高后,双峰均变为单峰,NO生成总量降低,燃料N向NO转化率降低,N转化率达稳定时刻的时间向前推移60 s;温度维持1 000℃恒温,各氧气浓度条件下均有双峰结构,燃料N转化率随氧气浓度升高,N转化率基本保持不变,只有在ρ(O_2)∶ρ(CO_2)=4∶6时,表现出降低趋势,N转化率达稳定的时间向后延迟210 s。     

NOx和/或NH3气氛下SO2在高岭土表面非均相转化的实验研究

利用自制气溶胶反应器研究了NO_x和/或NH_3气氛下SO_2在高岭土表面的非均相转化过程,应用扫描电镜(SEM)对高岭土颗粒物形貌进行了表征.结果表明:高岭土颗粒表面的SO_2非均相转化致使其成分和形貌产生了较大变化.相同实验条件下,SO_2转化的协同作用程度由高到低依次为NH_3、NO_x/NH_3和NO_x气氛,相对湿度40%、有光照条件下,SO_2转化量增幅最高可分别达125%、75%和50%.所有气氛下,协同作用在无光照时在高相对湿度(40%~70%)区间更为突出,有光照时其显著性则体现在低相对湿度(20%~40%)区间.SO_2、NO_x、NH_3三者共存时,在高岭土颗粒表面发生的非均相反应过程既有协同作用又存在竞争反应.     

关于有机废物类生物质能历史定位及其能源价值评估指标探讨

中国是煤炭消耗的第一大国,同时又是有机废物生物质贮存量第一大国。本文叙述了全球生物质能的历史定位,生物质能的主要评价指标,生物质的能源转换技术和生物质能可供给量模型分析与预测实例,以及我国有机废物类生物质能源化利用途径,并探讨了有机废物的能源利用与废物污染防治相结合的生物质能源发展道路。     

Welfare Balance of Different Interest Groups During Rural-urban Land Conversion

Rural-urban land conversion is currently a common social economic phenomenon during the process of economic development and rural urbanization in China. Rural-urban land conversion is positively effective as far as social and economic benefits are concerned （Yang, 2002）, but its negative effect is also evident, resulting in such problems as low efficiency of rural land configuration and loss of social welfare. Consequently, farmers should also have an equal chance to enjoy the social welfare enhanced by land conversion. Based on the theories of welfare economy, this paper puts forward policy suggestions by discussing the welfare changes of various interest groups, builds the model of welfare distribution, and analyzes the conditions of maximizing social welfare. The absolute and opposite value of social welfare is closely related with the speed of rural-urban land conversion, and governments should give farmers and collectives fair compensation to make up for the utility loss caused by land expropriation, which are conclusions drawn from this paper. This study aims to provide a theoretical basis for regulating targets and evaluation criteria, realizing the mechanism and implementation of public polices during rural-urban land conversion.