超声辅助乳化液相微萃取分析绿茶饮料和番茄汁中有机磷农药残留

农药施用于田间,必然会残留于环境中。农药残留的分析方法多种多样。为探究灵敏度高、重现性好的样品前处理方法,建立了超声辅助乳化液相微萃取,结合气相色谱和火焰光度检测器测定绿茶饮料和番茄汁中5种有机磷农药的方法,对萃取条件进行了优化,如萃取溶剂种类和体积、超声频率和时间、盐效应。在优化后的萃取条件下,5种有机磷农药实现良好分离,空白添加实验结果表明在0.1~10μg·L-1之间,线性相关系数在0.9985~0.9994之间,检测限在0.005~0.020μg·L-1之间,相对标准偏差(n=5)在4.3%~9.4%之间。在绿茶饮料和番茄汁实际样本检测中,目标分析物含量均低于检出限。样本添加回收试验的回收率均大于88.5%,相对标准偏差(n=3)在2.2%~9.8%之间,结果表明该方法用于液体样本中农药残留检测真实可靠。     

污泥热解气化技术的研究进展

通过热解气化等热化学转化方式将污泥转变为液体或气体燃料是极具前景的污泥利用方式之一。从污泥的资源化利用方面着手,阐述了污泥热解气化技术的研究进展,分析了现有污泥热解气化工艺的优缺点和主要影响因素,并对该技术的发展趋势进行了展望。指出:高湿污泥与生物质混合进行共热解可以提高原料的转化率和整个系统的热效率;高效污泥热解气化装置的研发是目前污泥热解气化技术领域亟待解决的问题。     

Evolution of China’s water issues as framed in Chinese mainstream newspaper

There is an urgent need globally to trigger fundamental societal changes in water management away from existing unsustainable paradigms. This paper attempts to understand the evolution of newspaper coverage of water issues in China by analyzing water-related articles in a major national newspaper, the People’s Daily, over the period 1946–2012 using a content analysis approach. The major findings include the following: (1) water issues were in relatively prominent positions in the newspaper; (2) the reporting of water issues in China experienced three stages: 1946 to the middle of 1980s—flood and drought control and water for food production, the middle of 1980s to 1997—water for economic development, and 1998 to the present—water for the environmental sustainability and economic development; (3) the reporting of water issues in the People’s Daily clearly reflected China’s top-down water resources management system, and no “real” public opinions on water were reported during the study period; and (4) the People’s Daily is just a wind vane of Chinese mainstream values and policies on water. The findings supported the realist assumption that the societal value changes on water issues in China were triggered by a range of factors including biophysical pressure (floods and droughts), political campaign (the Cultural Revolution), macro-economic reform (Reform and Opening-up), water institutional arrangement (the Water Law), and water management reform (the No. 1 Central Document on water reform). While there are similarities and differences between this study and other studies, important implications for more sustainable water management are a need to strengthen academic specialists’ and NGO’s voices in the newspaper to create a better informed public, and to stimulate practices toward sustainable water use.     

Effect of Nucleation of Tricalcium Phosphate and Isothermal Annealing on the Crystallization of Poly(l-lactide-co-glycolide)

We investigated the effect of nucleation and isothermal annealing on the crystallization behavior of a random copolymer, poly(l-lactide-co-glycolide) (PLLGA), with monomer molar ratios of 85/15 (PLLGA85/15) by scanning electron microscopy, polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction, and examination of the tensile properties of the resultant product. The effect of heterogeneous nucleation was assessed by the addition of tricalcium phosphate (TCP) as a nucleating agent. Nucleation and isothermal annealing of PLLGA at 130 °C were conducted to improve the degree of crystallinity of the copolymer. The fracture surfaces of the TCP/PLLGA85/15 composite bar showed a considerable number of spherulites with TCP as their nucleus. Addition of TCP and subsequent annealing improved the degree of crystallinity. After annealing, the TCP/PLLGA85/15 composite samples gained nearly the same strength that the pure PLLGA85/15 samples possessed. It is believed that this method will enhance the practical application of this nucleating agent in the processing of polymers.     

城市生活垃圾分选技术探究

随着人们生活水平的提高,城市的生活环境也在逐渐变化,城市生活垃圾的种类及物化特性也逐渐变得复杂.首先概括了传统的生活垃圾处理方法,重点总结了传统垃圾分选技术的进展,介绍了一些新的垃圾处理技术,如红外吸收光谱分析技术、图像识别技术、变重分选、温度传感技术等,在此基础上对传统技术及新技术的研究提出建议,认为一些在其他领域兴起的技术也 行变革进入该领域,以提高垃圾的无害化和资源化程度,有利于环境保护和社会的可持续发展的建设.     

现代生物技术在环境监测中的应用

随着分子生物学的迅速发展,现代生物技术在环境监测中的应用越来越广泛。文章解释了与环境科学密切相关的生物芯片、生物传感、流式细胞测定、单细胞凝胶电泳、微核、PCR和酶联免疫吸附检测技术,概述了这些技术的特点及应用情况。提出了在环境监测中,根据实际情况,联合应用,才能充分发挥各种技术的作用,为环境监测提供有力支持。     

丙烯酸废水处理工程实例

采用气浮-动态微电解—水解酸化—接触氧化工艺,对无锡某化工总厂丙烯酸废水原工艺和设备进行了改造,经过调试运行,监测结果表明,进水COD为6 000～10 000 mg/L时,处理出水COD小于60 mg/L。出水达到太湖地区重点工业行业主要水污染物排放标准。     

溇水上游古堰塞湖的发现及其水电工程意义

对溇水上游河湾岩溶渗漏研究中,在湘鄂交界的溇水河谷,发现了大型古滑坡体和堰塞湖沉积粘土层并对其进行了研究。对古滑坡体和堰塞湖作了简要介绍,对一些主要问题进行初步讨论和分析。古滑坡体约2000×104 m3,进入河道长度大于 1000 m;湖相沉积层厚度大于48 m,最大出露高程2841 m,根据14C测试,古堰塞湖形成于 10760±130~16880±250 a BP。通过分析认为堰塞湖水位大于285 m,堰塞湖沉积粘土层中出露的高硫酸盐地下水与当时沉积环境和粘土层本身无直接联系,沿河两岸粘土层产状变化可能与再次滑坡有关联;该研究成果对当前水电工程建设和研究溇水河流发育史、现代江河灾难性地质灾害的形成演化具有一定参考价值     

钢结构人行天桥自振频率优化分析

为了提高人行天桥的整体安全性,该文在结构设计的理论基础上提出了一系列有效措施。以楚雄市某钢箱人行天桥为依托,采用结构优化的方式,利用有限元软件建立参数化模型,以梁高和二期荷载为变量,以基频和时程为目标函数,分别将钢箱梁梁高增加20 cm和30 cm,将原混凝土铺装更换为轻型材料聚氨酯塑胶,天桥的基频提高到原来的两倍多。结果表明:梁高和铺装对人行天桥抗震性能有着显著的影响,增加梁高,采用轻型铺装,能有效地优化人行天桥的自振频率,保证了结构安全,可为类似结构的安全运行提供有力参考。     

军事装备使用风险初探

装备的安全使用是部队安全和战斗力的重要组成部分。由于装备复杂性和使用环境的严酷性,使装备使用过程存在较大的风险性。本文提出了装备使用风险的概念,装备使用风险是装备事故可能性与后果严重度的度量,并划分了风险类型。重点对装备使用风险的特点、影响和因素进行了分析,认为装备使用风险因素复杂,对部队安全和任务的完成有重大影响,需要进行风险管理和控制。最后,讨论了装备使用风险管理的原则和要求,以期促进部队装备安全使用和风险管理工作,从而提高部队的战斗力。