新型吸收剂净化吸收甲苯废气的实验研究

选择柠檬酸钠水溶液、Tween-20水溶液、檬酸钠-Tween-20混合水溶液、新型矿物油及新型矿物油-水作为研究对象,实验研究对比了几种吸收剂对甲苯废气的吸收效果。通过实验分析可知,檬酸钠水体系对甲苯废气吸收能力有限,加入盐类可小幅增强其水体系对于甲苯废气的吸收效果,其中Tween-20水溶液吸收剂对甲苯废气吸收率较柠檬酸钠水体系高;新型矿物油对甲苯废气有着较好的处理效果,吸收率最高可达97%,而新型矿物油-水混合吸收剂中单位体积新型矿物油对甲苯废气吸收率较新型矿物油吸收剂提高45%,且具有吸收效率高、分散性好、再生成本低的优点。     

桑色素-吐温-20胶束增溶分光光度法测定微量铁

本文对铁（Ⅲ）与桑色素（Ｍｏｒｉｎ）的显色反应进行了研究。在非离子表面活性剂吐温－２０存在下,于ｐＨ４．１的邻苯二甲酸氢钾缓冲溶液中,铁（Ⅲ）与桑色素形成稳定的黄色配合物,其组成比为Ｆｅ（Ⅲ）∶Ｍｏｒｉｎ＝１∶３,最大吸收波长为４１８ｎｍ,表观摩尔吸光系数为６．６９×１０４Ｌ／ｍｏｌ·ｃｍ,铁（Ⅲ）浓度在０～１６μｇ／２５ｍｌ范围内符合比耳定律。方法简便、快速,选择性好。应用于环境水样和植物中微量铁的测定,结果满意。     

Ecological consequences of forest elephant declines for Afrotropical forests

Poaching is rapidly extirpating African forest elephants (Loxodonta cyclotis) from most of their historical range, leaving vast areas of elephant‐free tropical forest. Elephants are ecological engineers that create and maintain forest habitat; thus, their loss will have large consequences for the composition and structure of Afrotropical forests. Through a comprehensive literature review, we evaluated the roles of forest elephants in seed dispersal, nutrient recycling, and herbivory and physical damage to predict the cascading ecological effects of their population declines. Loss of seed dispersal by elephants will favor tree species dispersed abiotically and by smaller dispersal agents, and tree species composition will depend on the downstream effects of changes in elephant nutrient cycling and browsing. Loss of trampling and herbivory of seedlings and saplings will result in high tree density with release from browsing pressures. Diminished seed dispersal by elephants and high stem density are likely to reduce the recruitment of large trees and thus increase homogeneity of forest structure and decrease carbon stocks. The loss of ecological services by forest elephants likely means Central African forests will be more like Neotropical forests, from which megafauna were extirpated thousands of years ago. Without intervention, as much as 96% of Central African forests will have modified species composition and structure as elephants are compressed into remaining protected areas. Stopping elephant poaching is an urgent first step to mitigating these effects, but long‐term conservation will require land‐use planning that incorporates elephant habitat into forested landscapes that are being rapidly transformed by industrial agriculture and logging.     

某20#钢腐蚀穿孔失效原因分析

目的 某船20#钢管投运不久后管段出现严重的腐蚀穿孔,通过对失效管段进行研究,以分析其失效原因。方法 通过电感耦合等离子体发射光谱仪、碳硫分析仪、金相显微镜等对材料材质进行材质符合性分析及金相组织分析。通过场发射扫描电子显微镜观察蚀坑微观形貌,并结合X射线衍射仪及显微拉曼光谱仪,对失效部位周围的腐蚀产物进行成分分析。通过电化学测试及微生物鉴别培养,进一步确定腐蚀的发生原因及机理。结果 材料符合性分析说明,此20#钢管束成分符合标准要求。通过形貌观察发现,20#钢蚀坑边缘呈阶梯状,具有明显的攀爬现象,蚀坑周围呈黑色。X射线能谱仪分析结果表明,20#钢腐蚀穿孔处内表面异常存在大量硫元素。通过拉曼分析及XRD分析发现,硫元素主要以硫酸盐及硫化物的形式存在。电化学测试结果表明,在含硫化物的溶液中,20#钢的腐蚀速率明显提升。进一步对腐蚀产物进行微生物培养,发现了硫酸盐还原菌的存在。结论 微生物腐蚀是引起20#钢管束穿孔的主要原因。     

太阳辐射试验标准中的太阳光谱分布

目的为太阳辐射试验标准、光老化试验标准修订时正确选择太阳光谱提供依据。方法辨析CIE NO.20,CIE NO.85两种出版物太阳辐射光谱特点,从五个方面对此问题进行探讨,统计这两种太阳辐射光谱带宽辐照度的误差;分析相对空气质量、臭氧与水分、云层光学厚度、地表反射率等因素对太阳辐射光谱辐照度的影响;分析人工辐射光源光谱分布特点,以及它们与太阳辐射光谱的差别;分析当前光老化试验标准对光谱辐照度允差的要求;介绍光老化试验结果间的可比性。结果 CIE NO.85光谱更准确、更细致,但其波长范围较窄,两种光谱辐照度的差别很小,大气环境中许多因素会降低到达地面的光谱辐照度;人工辐射光源光谱与太阳光谱的误差、光老化试验标准中光谱辐照度允差都远大于前述太阳辐射光谱间的误差,标准对太阳光谱波长范围的要求比CIE NO.85光谱宽。结论太阳辐射试验标准、光老化试验标准修订时,仍可选用CIE NO.20光谱作为太阳辐射光谱。     

CL-20/HTPB热分解机理的ReaxFF/lg反应分子动力学模拟

目的 揭示CL-20和HTPB复合体系的热分解机理,同时为CL-20/HTPB复合推进剂配方设计与应用提供理论依据。方法 采用反应分子动力学方法(ReaxFF/lg),研究CL-20/HTPB混合体系在2 500~3 500 K中5个温度下的热分解机理。结果 混合体系中的CL-20分子间反应路径仍为脱硝基和开环等反应。HTPB为混合体系引入大量的H原子与OH基团,这些自由基会与CL-20及CL-20的分解产物发生反应,例如与HNO2的大量化学反应促进了CL-20的热分解。相比CL-20单质体系,混合体系下,HNO2生成反应数量均有不同程度的增加。通过与单组分产物数量的比较可以发现,H2O的含量大大增加,且曲线到达峰值的时间更短,体系分解反应速率更快,同时CO2的含量也大幅度地减少。除此之外,所计算的混合体系的活化能(Ea)与指前因子的自然对数lnA分别为114.684 kJ/mol与25.896。对比CL-20单质体系,混合体系的活化能较小。结论 HTPB会对CL-20的热分解起到促进的作用,降低了系统对热刺激的不敏感程度。     

Prenatal diagnosis of occipital encephalocele,mega-cisterna magna,mesomelic shortening,and clubfeet associated with pure tetrasomy 20p

We present the first case of a fetus with pure tetrasomy 20p proven by cord-blood sampling at 24 weeks of gestation. This case was diagnosed in utero with multiple congenital anomalies including occipital encephalocele, mega-cisterna magna, mesomelic shortening, and clubfeet. An analysis of GTG-banded chromosomes of 20 metaphase cells was performed. Female karyotype [47,XX, +i(20)(p10)] was revealed in all cells. Pure tetrasomy 20p was confirmed using fluorescent in situ hybridization (FISH) with a telomere probe for chromosome 20p in all seven metaphase cells. The pregnancy was terminated because of associated multiple anomalies and severe oligohydramnios. The postmortem examination confirmed the prenatal diagnosis. Copyright © 2003 John Wiley & Sons, Ltd.     

Prenatal diagnosis of trisomy 20 by chorionic villus sampling (CVS): a case report with long-term outcome

A case of prenatally diagnosed non-mosaic trisomy 20 in cells cultured from a chorionic villus sample (CVS)is presented. The term placental karyotype was also non-mosaic trisomy 20. The karyotype of thenewborn was 46,XY/47,XY,+20 in foreskin cultures and in a second skin culture; blood lymphocyte culture was 46,XY. Aside from diffuse, hypopigmentary swirls along the lines of Blaschko observed on hisextremities and trunk, referred to as hypomelanosis of Ito, the patient is clinically normal at 8¾ years ofage. In addition, he is one of the oldest reported cases of mosaic trisomy 20 confirmed after birth forwhich the clinical outcome has been monitored. This case demonstrates that these trisomy 20 findings are compatible with normal psychomotor development and phenotype. Copyright © 2001 John Wiley & Sons, Ltd.     

At the source: the origins of the Massachusetts toxics use reduction program and an overview of this special issue

This special edition of the Journal of Cleaner Production celebrates the twentieth anniversary of a piece of legislation that has special significance to the environmental movement - the Massachusetts Toxics Use Reduction Act of 1989 (TURA). Most of the papers in this issue were presented at a symposium to commemorate the twentieth anniversary that was held on November 4, 2009.Much has been written about the Massachusetts Toxics Use Reduction Program. It has been heralded as a major pollution prevention success story. It has been lauded as a premier American example of the precautionary principle in action. It has been condemned by the American chemical industry trade association as “bad for the chemical industry”. And it has been praised by the Ford Foundation and Harvard’s Kennedy School of Government as an award-receiving example of innovation in government (Harvard Kennedy School, 2005).Looking back now to some twenty years ago—back to the early origins of the program concept—it can be seen both as a landmark breakthrough in international chemicals policy, and as a fairly conventional next step in the political evolution of Massachusetts environmental policy.Where did this idea come from? How did it develop? How were pieces put together? Why did Massachusetts adopt such an idea into law? And how did the idea change during the early years of implementation? This paper provides a brief history of the development of the concept of toxics use reduction and the process by which it was drafted into law in Massachusetts, followed by an introduction to the articles included in this special edition and their assessment of TURA - past, present, and future.     

Social licence and mining: A critical perspective

In 2002 the International Institute of Environment and Development published the landmark report Breaking New Ground: Mining, Minerals and Sustainable Development (MMSD). The report portrayed an industry distrusted by stakeholders and under threat from opposition groups. When read closely, the MMSD report reveals an inextricable link between industry's ‘survival’ instincts and the notion of a social licence. Within the context of a growing divergence around the expectations of minerals-led development, social licence has emerged as an industry response to opposition and a mechanism to ensure the viability of the sector. The objective of this article is to reinvigorate discussion and debate over how best to frame the industry's social and environmental obligations and how these obligations can be met by the sector. Where social licence has contributed to raising the profile of social issues within a predominantly industrial discourse, a primary failure is its inability to articulate a collaborative developmental agenda for the sector or a pathway forward in restoring the lost confidence of impacted communities, stakeholders, and pressure groups. We argue that a necessary first step in this process is for industry to reconcile its internal risk-orientation with external expectations which requires a less defensive and more constructive approach to stakeholder engagement and collaboration.