水体样本重金属离子检测方法探究

水体重金属离子污染主要是指重金属离子污染物进入水体后对水体所造成的污染。重金属离子主要来源于工业废水,冶炼、化工、电子等工业生产所产生的废水中均含有一定量的重金属离子。若未对重金属废水进行有效处理,就直接排放到自然水体当中,会给生态环境、食物链及人类健康带来严重危害。基于此,本文对水体样本重金属离子检测方法进行了综合性阐述,以供参考。     

土壤污染物的频谱激电响应特征研究

为了探讨使用频谱激电法检测土壤重金属污染和盐碱化的可行性,本文通过制作不同重金属污染和不同盐碱化程度的规则土壤样品,利用LCR电性测试仪采用二极装置测量宽频带范围(0.001Hz~100k Hz)内的复阻抗响应。实验结果表明,随着重金属(铬)污染浓度增加,土壤激电效应逐渐增强;随着盐碱化(Na Cl)浓度增加,土壤激电效应变化不大。因此,利用频谱激电法检测重金属土壤污染物确实可行性,而检测土壤盐碱化则不可行。     

绿色合成方法修复水体中的重金属污染

本文分析重金属离子污染对人类产生的危害,从仿生合成角度,阐述植物治理水体中重金属离子污染的意义,实现方法。     

南太湖地区农村小流域非点源污染调控研究

随着农村非点源污染问题的日益突出,将总量控制体系纳入到非点源污染的防治中已具有重要的作用和意义。许多研究都对减少农村非点源污染提出了一些政策性建议和工程性措施,但对于农村非点源污染物排放量的具体调控研究较少,没有按照"公平、效率、可行"的原则进行污染物总量的分配。基于对南太湖地区农村小流域典型污染物输出特征的研究,本文利用排污系数法对农村非点源污染物排放量进行了快速估算,采用最大纳污量优化程序计算了农村小流域内水体纳污量与环境容量,并提出相应的污染物削减对策。研究结果表明:南太湖地区农村小流域污染物输出主要超标因子为总磷,农村生活污染为主要污染源。流域污染物输出浓度受季节变化影响较大,提高水体自净能力能够有效缓解夏季污染物对水质的影响。此外,依据BAT体系建立的最大排污量优化计算方法可以快速有效的制定出农村小流域非点源污染控制方案。     

重金属废水的植物修复技术

植物修复技术是近年来发展起来的用于清除水体中重金属污染的生态技术。植物修复重金属污染，是通过植物根系移去、挥发或稳定水体环境中的重金属污染物，降低污染物申的重金属毒性，具有成本低、不破坏土壤和河流生态环境、不引起二次污染等优点。     

松花江湿地植物对重金属降解的实验研究

哈尔滨松花江湿地由于长期承泄工业废水、生活污水而受到不同程度的污染,为了治理和恢复退化的湿地生态系统,了解湿地植物吸收降解重金属的能力,对香蒲、水芹菜、浮萍降解重金属Cd、Pb、Zn做了室内模拟实验的研究,实验结果表明,湿地植物对三种重金属均有不同程度的吸收,其中香蒲对Zn还有一定的富集作用,植物对污染物的去除与污染负荷、植物种类等均有关,而且吸收量有一定限度,土壤中重金属的含量明显高于水中,植物对污染物的吸收以从底泥中吸收为主。     

探索神奇的生物世界——记合肥工业大学生物科学系教授曹树青

土壤重金属污染是全球面临的重要环境问题之一,因为土壤污染的重金属可通过农作物而进入食物,严重影响食品安全和人类健康.为解决这一问题,科学家采取了很多措施,植物修复基因工程便是解决土壤重金属污染的重要途径之一. 其原理是利用绿色植物来转移、容纳或转化污染物使其对环境无害.研究表明,通过植物的吸收、挥发、根滤、降解、稳定等作用,可以净化土壤或水体中的污染物,达到净化环境的目的.而在其中,植物修复的对象是重金属、有机物或放射性元素污染的土壤及水体.因而,植物修复基因工程是一种很有潜力、正在发展的清除环境污染的绿色技术.     

鱼体中有害重金属含量及其分布特征

有毒有害重金属作为一类重要污染物其对鱼类的毒害作用,日益受到人们的广泛关注。随着重金属摄入量的增加,其在动物体内的浓度会递增,最终通过食物链的转移过程而被人体吸收,毒害到处于高位营养级的生物,因此,水生生物尤其是鱼类对有害重金属的吸收和积累作用一直以来都是环境科学研究分析的焦点。本文分析总结了近年来国内外对鱼体内有毒有害重金属的研究状况,不同种类的鱼受重金属污染的程度不同;不同地区鱼体受重金属污染的特点,以及鱼体不同部位重金属含量分布特征,目前鱼体重金属的检测检验技术。     

微生物发光技术在净化污染河塘的效果分析

提出一种微生物发光技术在净化河塘污染效果分析方法。首先依据微生物发光技术的原理,确定微生物发光技术检测步骤为提取图像样品并添加荧光素来测定污染物的发光量,求出污染物浓度与活菌数。采用多光谱成像系统,获取350~700 nm波段范围的污染物光谱图像序列,对污染物图像进行分层像素的整合处理,利用欧氏距离度量不同分块污染物图像光谱的特征差异,获取动态区域光谱特征向量,依据目标与图像间光谱特征向量差异,完成对微生物发光技术在净化河塘污染的效果分析。实验证明,微生物发光技术可净化生活污水污染富营养化河塘。     

蜗牛新贡献:以毒攻毒

以身试毒 研究人员对受污染土壤的危险等级进行评定时,关键的依据是:"污染物只有溶解或悬浮在渗透水分的土壤时,才可能被生物吸收."而重金属等与土壤颗粒紧密结合,所以无法被以土壤为食的生物吸收,难以对人类造成很大伤害.     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.     

Cooler temperatures inductive to locust outbreaks

Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.     

To serve and promote science development via innovation

CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing.     

Tracing the origin and early radiation of birds——Paleornithologist ZHOU Zhonghe

With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants."     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.     

Prevalence of soft neurological signs in Chinese people

Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.     

Our Own Devices: Heterotopic Communication, Discourse, and Culture in the Information Society 1

The main premise of this article is that in information societies generally, and in virtual social contexts particularly, a distinctive style of interaction to facilitate the communication of difference, heterotopic communication , has emerged. It rests on two cultural foundations: an ideological belief in the positive, socially integrating power of communication, and a prevailing ethic of instrumental rationality, subjective individualism, and strategically practiced self-interest. The former is demonstrated by the use of simulation and spectacle as sources of information; exhibitionism/voyeurism as a communicative style; and the awareness of surveillance. The latter is seen in the competitive use of knowledge as a commodity; a surface globalism masking deep parochialism; lateral as well as vertical information inequity; and the use of public versus private as strategies for engagement rather than as spaces. Those who engage in heterotopic communication resort to their 'own devices' both in the sense of personal agendas, strategies, interests, and interpretations, and in the form of the telecommunication tools that help realize them. These personal and technological devices allow individuals with the right educational and technical resources to avoid exposure to disagreement, difference, or other information that does not serve their direct purposes or reflect their particular views of the world; yet they also help convey the appearance of openness, availability, and cooperation. This style of interaction is used strategically in combination with information and communication technologies to gain social or economic advantages, but it may encourage social separatism and parochialism, inhibit the negotiation of disputes, and emphasize competing interests.