P450酶系对污染物的生物指示和催化降解机制

细胞色素P450酶系是广泛存在于不同生物体内的含有多种超家族CYP450血红素蛋白或相同结构域的一系列酶,是多组分电子传递链的终端氧化还原酶。最新研究发现,利用P450在生物体内的含量/活性与污染物浓度的定量响应关系可实现环境污染的早期预警和诊断,对环境污染的监测和预报具有重要意义。更重要的是,P450酶系被认为是生物对内源或外生污染物代谢途径的启动催化因子。P450的脱卤化、羧基化、脱烷基化、环氧化等催化作用在诱导污染物的分解代谢过程中起核心作用。本文综述了P450酶系的结构、催化过程和诱导抑制机理,分析了其在环境污染物的生物指示和催化降解中的应用进展,以便为利用P450进行环境预警和生物修复提供系统的理论和技术支持。     

北京地区2003～2007年人类活动氮累积状况研究

人类活动引起的生态系统的氮输入和累积对区域环境特别是水环境有着潜在的重要影响.引入人类活动净氮累积的概念(net anthropogenic nitrogen accumulation,NANA),将NANA定义为人类活动氮的输入和输出之差,它是通过大气沉降、肥料应用、人类食物和动物饲料、氮固定和河流的累积这五项来计算...     

CSR codes and the principal-agent problem in supply chains: four case studies

The benefits of corporate social responsibility (CSR) affect the entire supply chains a firm participates in. However, not every firm is in a position to force the implementation of CSR in its supply chains as some, especially small and medium-sized enterprises (SMEs), lack the necessary power. Chain directors can implement it acting as a principal, whereas the other chain members can act as agents.In the principal-agent framework, two main problems occur due to information asymmetry: adverse selection and moral hazard. This paper examines how a code of conduct (i.e. Social Accountability 8000) can help address the principal-agent problem, for SMEs, between chain directors and partners. The research method involves four case studies on CSR practices as implemented by Italian and Dutch SMEs within their supply chains.     

Collaborative activity with business partners for improvement of product environmental performance using LCA

Collaborative activities with business partners have potential to improve environmental performance of product and life cycle assessment (LCA) is an essential technique to implement eco-design of product and production process. However, collection of LCA data from supply chain is a major issue for LCA practitioners. We propose a Supply Chain Collaboration Model (SCCM), which is a framework for collecting producer-specific LCA data from business partners and for promoting improvement activity of product environmental performance. We demonstrate the practicability of the SCCM using three case studies. In each case study, two or three partner companies organized a product improvement project and carried out process analysis techniques such as LCA and material flow cost accounting (MFCA). As a result, improvement activities from the economical standpoint could provide an incentive for business partners to collect LCA data, and thus the SCCM is an effective framework for eco-design.     

Integrating carbon footprint into supply chain management: the case of Hyundai Motor Company (HMC) in the automobile industry

The purpose of this paper is to improve our understanding of carbon footprint within the context of automobile supply chain management. The case study approach is employed as a research method. Primary data were collected through site visits and extensive interviews with HMC’s corporate and plant management. First, identification and measurement of direct and indirect carbon footprint is critical for mitigating supply chain risks. Second, setting the system boundary of measurement is another important issue to integrate the issue of carbon footprint into supply chain management. Third, developing a map of product carbon footprint facilitates identification and measurement of carbon emissions across the supply chain. Companies today operate in a carbon-constrained world. In particular, the automobile industry is under pressure to take a close look at its product carbon footprint. Managing the downstream consequences of the use of its products and inputs from upstream suppliers is critical for developing carbon risk-mitigated supply chain management. This paper is of benefit to academics and managers by providing a new way to integrate carbon emissions in supply chain management. Since climate change and carbon footprint present challenges to many industries, increasing our understanding of how to integrate carbon footprint in supply chain management is necessary, but has seen little research in the automobile industry.     

水解酸化-SBR工艺在食品加工废水处理中的应用

某食品加工厂原有的废水处理厂处理工艺不能满足GB8978-1996《污水综合排放标准》中一级标准的要求,需要改造,改造采用混凝沉淀-水解酸化-SBR处理工艺。     

活性炭纤维-固相微萃取技术快速检测烤肉中多环芳烃

文章采用新型活性炭纤维(ACF)做为固相微萃取(SPME)的萃取纤维与气相色谱-质谱(GC/MS)联用,建立了一种快速检测烤肉中持久性污染物多环芳烃(PAHs)的方法.烤肉由于其独特的风味深受人们喜爱.但是,在烤肉中含有致癌的PAHs,影响着人们的身体健康.烤肉中PAHs最佳提取条件为:2g匀浆样品,丙酮+甲醇(1∶0...     

崩塌块体形成原因及其演变过程探讨

本文根据工程实例对崩塌块体进行了定义,分析了崩塌块体的形成原因及其演变过程,并提出了“类多米诺骨牌式”崩塌和“链式反应”崩塌的效应,用于解释岩性存在软硬差异的沉积岩崩塌块体发生滚落的原因.     

基于置信规则的村镇应急避难场所暴雨灾害链风险诊断*

为解决村镇应急避难场所面临暴雨灾害时的风险问题,基于故障树和置信规则库推理方法,提出暴雨灾害链和村镇应急避难场所功能破坏链相结合的场所避难功能失效风险诊断模型。根据事故致因理论推理灾害节点变量,通过故障树描述灾害链,运用关联规则从历史灾害数据中挖掘规则,建立置信规则库系统,构建村镇应急避难场所功能失效风险诊断模型,并以四川省某寄宿制学校为例进行模型验证。研究结果表明:该模型可实现不同证据组合下村镇应急避难场所功能失效风险的诊断推理;实例的模型诊断结果与实际情况吻合,证实该模型能够科学地诊断村镇应急避难场所面临暴雨等恶劣自然条件时存在的风险,可为村镇应急避难场所规划设计和应急管理提供理论支撑。     

LNG船码头锚链安装的安全管理

本文针对LNG船码头锚链安装工艺,通过作业人员现场的实地考察,对LNG船码头锚链安装施工作业各个环节进行了风险评估,并根据实际的锚链安装过程,指出了船厂值得借鉴的经验和建议。