木工机床切削机构产生噪声的原因及刀具降低噪声新技术

我国的木材加工企业普遍存在严重的噪声污染 ,极大地损害了工作者的身心健康 ,是迫切需要解决的重要问题。为了控制木工机床的噪声 ,分析和讨论了产生噪声的原因 ,指出切削机构是噪声的主要声源。探讨了降低噪声的途径 ,综合评述了国外木工刀具降噪新技术。在工业发达的国家 ,现代木工刀具的设计与制造均考虑了降噪措施 ,其技术原理集中于控制气流在刀槽或齿槽中涡流产生的空气动力性噪声和防止刀具振动时产生的机械噪声两方面。这些新技术已用于生产中 ,降噪效果明显 ,值得借鉴。笔者强调 ,开发低噪声木工刀具 ,保障劳动者的人体健康 ,是我国木材加工工业文明发展的标志     

新农村建设中的环境污染及措施的探讨

近年来,各部门不断加大农村污染防治和生态保护力度,创新农村环保新机制,农村环保工作取得了积极进展,但是一些新旧环境问题依然存在,并制约着农村的可持续发展。文章对农村环境污染的现状、产生污染的原因及解决对策等方面进行了探讨。     

生态红线保护下的两江新区土地利用/覆盖情景模拟及生态价值评估

生态保护红线的划定对于维护国家和区域生态安全具有非常重要的作用,是我国在生态环境保护方面的重要举措.为分析生态保护红线划定后区域生态系统服务价值的变化情况,以重庆市两江新区为例,采用CLUE-S模型对未来的土地利用变化情况进行情景模拟,并在此基础上对各地类价值系数进行优化调整构建生态系统服务价值评估优化模型,对不同情景下的生态系统服务价值进行定量计算,分析生态系统服务价值的敏感度及变化度.结果表明:①采用CLUE-S模型对两江新区的未来土地利用进行空间模拟效果较好（Kappa系数达到0.82以上）,模型的普适性较好.②生态价值敏感度结果表明两江新区的生态系统服务价值对价值系数的变化缺乏弹性,结果的可信度高.③2020年生态保护情景下,林地的面积增加量大于自然增长情景,城镇和工矿用地则相反,生态保护红线对于城镇扩张起到了一定的约束作用.④2014年现状、2020年自然增长情景和2020年生态保护情景下的生态系统服务价值分别约为10.53×108、10.50×108和10.88×108元,两种未来情景下耕地的生态系统服务价值减少最为明显,林地、水域服务价值均表现出增加的趋势.⑤林地和水域的生态价值变化度表明其面积变化对生态系统服务价值的影响较大.研究显示,CLUE-S模型进行小区域的土地利用变化情景模拟效果较好,构建的生态系统服务价值评估优化模型计算结果的可信度较高.政府相关部门可以根据生态保护红线及生态系统服务价值评估结果,进一步优化生活、生产和生态空间,使其在城市规划、绩效考核和生态补偿中得到实际运用,在区域的经济可持续发展中起到支撑作用.      

新型城镇化背景下城乡环境基本公共服务均等化推进路径

新型城镇化迫切需要推进城乡环境基本公共服务均等化,而农村环境公共服务的不足成为实现环境基本公共服务均等化的阻碍和制约。在阐述新型城镇化和城乡环境基本公共服务均等化之间关系的基础上,从环境基本公共服务投入总体不足、供给主体单一、城乡不均等突出等方面指出:当前阶段城乡环境基本公共服务均等化现状和面临的问题。探讨了城镇化背景下城乡环境基本公共服务均等化的发展重点领域,包括饮用水安全保障、清洁的大气、污水垃圾治理设施、环境信息服务等,认为推进城乡环境基本公共服务均等化宜采用政府推动、市场参与、多元化供给的协调推进路径,并提出政策建议。     

四川省新型干法水泥行业发展概况及其环境问题分析

本文简述了四川省“十一五”期间新型干法水泥工业发展概况和取得的环境效益,分析了新型干法水泥工业发展中面临的环境问题,提出利用新型干法水泥回转窑处理有机废物和危险废物是今后水泥行业可持续发展的一个重要方向。     

Walking to school: Community design and child and parent barriers

The roles of community design and parent and child perceptions of walkability to school are tested for associations with walking in three communities: a walkable new urbanist community, a mixed community (standard suburban community where the walk to school traversed part of the new urbanist community), and less walkable standard suburban community. Perceived environmental barriers to walking to school are measured and compared for fifth graders (n = 193) and their parents (n = 177). Results showed that children and parents often agreed on walking barriers, except an interaction showed that — in the less walkable community — parents perceived worse barriers than did their children. Perceptions of barriers increased from walkable, to mixed, to less walkable communities. Students walked more when they attended the school in the walkable community, they lived near school, parents and children perceived fewer barriers to walking, and children had lower BMI scores, net of demographic controls. Thus the walk to school is embedded within multiple types of supports, all of which should be addressed to encourage walking to school.     

Towards a relational paradigm in sustainability research,practice, and education

Relational thinking has recently gained increasing prominence across academic disciplines in an attempt to understand complex phenomena in terms of constitutive processes and relations. Interdisciplinary fields of study, such as science and technology studies (STS), the environmental humanities, and the posthumanities, for example, have started to reformulate academic understanding of nature-cultures based on relational thinking. Although the sustainability crisis serves as a contemporary backdrop and in fact calls for such innovative forms of interdisciplinary scholarship, the field of sustainability research has not yet tapped into the rich possibilities offered by relational thinking. Against this background, the purpose of this paper is to identify relational approaches to ontology, epistemology, and ethics which are relevant to sustainability research. More specifically, we analyze how relational approaches have been understood and conceptualized across a broad range of disciplines and contexts relevant to sustainability to identify and harness connections and contributions for future sustainability-related work. Our results highlight common themes and patterns across relational approaches, helping to identify and characterize a relational paradigm within sustainability research. On this basis, we conclude with a call to action for sustainability researchers to co-develop a research agenda for advancing this relational paradigm within sustainability research, practice, and education.     

南岳森林群落生物多样性研究(Ⅶ)物种相对多度的几何级数分布模型新算法

本文提出了物种相对多度几何级数分布模型的一种新算法即极大值算法,其公式如下: N′_i=N·G_b·(1-b)·b~(i-1) N_(max)/N=[(1-b)·b~(i-1)]/(1-b~s) 式中,N′_i为第i个物种的期望个体数目;N为实测总个体数;i=1,2,…,s为物种数目;C_b=(1-b~s)~(-1);b为参数;N_(max)为s个物种中最多个体数目。 结果表明:几何级数分布模型极大值算法与传统算法(即极小值算法)的结果完全一致,而且具有简便、准确之优点。     

Formation mechanism of typical aromatic sulfuric anhydrides and their potential role in atmospheric nucleation process

Sulfuric anhydrides,generated from the cycloaddition reaction of SO₃with carboxylic acids,have been revealed to be potential participants in the nucleation process of new particle formation (NPF).Hence the reaction mechanisms of typical aromatic acids (benzoic acid (BA),phenylacetic acid (PAA),phthalic acid (PA),isophthalic acid (mPA),and terephthalic acid(PTA)) with SO₃to generate the corresponding aromatic sulfuric anhydrides were investigated by density functional theory...     

Compilation of reaction kinetics parameters determined in the Key Development Project for Air Pollution Formation Mechanism and Control Technologies in China

A compilation of new advances made in the research field of laboratory reaction kinetics in China's Key Development Project for Air Pollution Formation Mechanism and Control Technologies was presented. These advances are grouped into six broad, interrelated categories, including volatile organic compound (VOC) oxidation, secondary organic aerosol (SOA) formation, new particle formation (NPF) and gas-particle partitioning, ozone chemistry, model parameters, and secondary inorganic aerosol (SIA) formation, highlighting the laboratory work done by Chinese researchers. For smog chamber applications, the current knowledge gained from laboratory studies is reviewed, with emphasis on summarizing the oxidation mechanisms of long-chain alkanes, aromatics, alkenes, aldehydes/ketones in the atmosphere, SOA formation from anthropogenic emission sources, and oxidation of aromatics, isoprene, and limonene, as well as SIA formation. For flow tube applications, atmospheric oxidation mechanisms of toluene and methacrolein, SOA formation from limonene oxidation by ozone, gas-particle partitioning of peroxides, and sulfuric acid-water (H₂SO₄-H₂O) binary nucleation, methanesulfonic acid-water (MSA-H₂O) binary nucleation, and sulfuric acid-ammonia-water (H₂SO₄-NH₃-H₂O) ternary nucleation are discussed.