公路设计中的环境保护工作

阐述了公路建设中环境保护工作的意义，提出在公路工程勘察设计工作中对环境保护的典型作法和取得的效果。     

Low-carbon transition of iron and steel industry in China: Carbon intensity, economic growth and policy intervention

As the biggest iron and steel producer in the world and one of the highest CO₂ emission sectors, China's iron and steel industry is undergoing a low-carbon transition accompanied by remarkable technological progress and investment adjustment, in response to the macroeconomic climate and policy intervention. Many drivers of the CO₂ emissions of the iron and steel industry have been explored, but the relationships between CO₂ abatement, investment and technological expenditure, and their connections with the economic growth and governmental policies in China, have not been conjointly and empirically examined. We proposed a concise conceptual model and an econometric model to investigate this crucial question. The results of regression, Granger causality test and impulse response analysis indicated that technological expenditure can significantly reduce CO₂ emissions, and that investment expansion showed a negative impact on CO₂ emission reduction. It was also argued with empirical evidence that a good economic situation favored CO₂ abatement in China's iron and steel industry, while achieving CO₂ emission reduction in this industrial sector did not necessarily threaten economic growth. This shed light on the dispute over balancing emission cutting and economic growth. Regarding the policy aspects, the year 2000 was found to be an important turning point for policy evolution and the development of the iron and steel industry in China. The subsequent command and control policies had a significant, positive effect on CO₂ abatement.     

太湖水体中悬浮颗粒物的比吸收光谱特性及其参数化分析

通过对太湖水体的野外采样,利用定量滤膜技术测量了水体中浮游植物色素的吸收系数(aph(λ))和非色素颗粒物的吸收系数(aNAP(λ)),进而推算比吸收系数.同时,对浮游植物色素和非色素颗粒物的比吸收系数的时空变化特征进行了分析.结果表明,浮游植物色素的比吸收系数(ap*h)在蓝光440nm的变化范围为0.008～0.268m2·mg-1,在红光670nm的变化范围为0.004～0.098m·2mg-1;;通过K-Mean算法将浮游植物色素的比吸收光谱分成3种具有不同光谱特征的类型,类别1、2和3占总数的百分比分别为61.0%、12.2%和26.8%,表明太湖水体中浮游植物色素的比吸收光谱是以类别1为主;;色素包裹效应因子Qa*(675)在Chla浓度<50mg·m-3时,随Chla浓度的增大迅速减小,而在Chla浓度>50mg·m-3时,其减小的趋势趋于缓慢,Qa*(675)与Chla浓度呈现出较好的幂函数关系.非色素颗粒物的比吸收系数(aN*AP)在蓝光440nm处的变化范围为0.012×10-3～0.143×10-3m2·mg-1,利用此处的比吸收系数建立的非色素颗粒物比吸收光谱的参数化模型,光谱曲线斜率...     

基于PBPK模型评价三氯乙烯的职业暴露健康风险

三氯乙烯(TCE)作为脱脂和清洗剂被广泛应用于五金、电镀和电子等行业。TCE的职业暴露会产生一系列健康风险,包括过敏症和致癌等。2012年TCE被美国环保局(US EPA)和国际癌症研究机构列为1类致癌物。采用吸附管采样-热脱附/气相色谱-质谱法分析了大连市某企业车间生产工况下空气中TCE浓度。基于生理学的药代动力学(PBPK)模型预测了呼吸暴露途径下TCE在职业工人体内组织中的动态分布、代谢产物生成情况和致癌风险。TCE在不同组织中预测的最大浓度呈现出脂肪肠充分灌注室支气管非充分灌注室肝脏静脉血动脉血的趋势。预测的与致癌有关的代谢产物最大浓度表现为三氯乙酸二氯乙酸三氯乙醛S-二氯乙烯基-L-半胱氨酸。在监测的TCE水平(39.2±24.4)μg·m-3下,暴露8 h·d-1,连续暴露20年,基于外暴露评价的职业工人致癌风险均值为1.31×10-5,该暴露水平下,基于PBPK模型预测的TCE内暴露与外暴露计算的致癌风险水平相近,但基于具有致癌性主要代谢产物的内暴露致癌风险值是外暴露风险值的1.17～1.73倍。TCE的暴露水平越高,基于内暴露方法和外暴露方法的致癌风险评价结果差异越大。敏感性分析表明,心输出血流量和充分灌注室血流量对PBPK模型输出结果具有重要影响。不确定性分析表明,模型参数变化会显著地影响PBPK模型输出结果,但变异在可接受水平。本研究结果说明,评价TCE暴露对人的致癌风险需要考虑其在体内的分布和代谢过程。     

扬州经济开发区发展循环经济的实践、对策和规划

扬州经济开发区通过国家生态工业示范园区的创建和国家循环经济试点工作,构建以工业共生、物质循环、自然和谐、宜业宜居为特征及资源节约型、环境友好型开发区。本文介绍了扬州经济开发区发展循环经济的实践情况,以“减量化、再利用、资源化”和“可持续性”原则为理念,分析了其循环经济发展存在的问题,并提出了相应对策和规划。     

好氧颗粒污泥处理青霉素废水研究

青霉素在其生产过中产生大量的废水,其COD值较高,生化性较差,成分复杂,微生物难以降解,其处理技术是世界性难题。文章采用以葡萄糖模拟废水培养的好氧颗粒污泥为接种体,经青霉素废水逐步驯化后,使其完全处理青霉素废水。实验结果表明,应用好氧颗粒污泥技术,处理青霉素废水,COD,NH3_N,TP去除率较高,具有很好的处理效果。     

Waste polyvinylchloride derived pitch as a precursor to develop carbon fibers and activated carbon fibers

Polyvinylchloride (PVC) was successfully recycled through the solvent extraction from waste pipe with an extraction yield of ca. 86%. The extracted PVC was pyrolyzed by a two-stage process (260 and 410 degrees C) to obtain free-chlorine PVC based pitch through an effective removal of chlorine from PVC during the heat-treatment. As-prepared pitch (softening point: 220 degrees C) was spun, stabilized, carbonized into carbon fibers (CFs), and further activated into activated carbon fibers (ACFs) in a flow of CO2. As-prepared CFs show comparable mechanical properties to commercial CFs, whose maximum tensile strength and modulus are 862 MPa and 62 GPa, respectively. The resultant ACFs exhibit a high surface area of 1200 m2/g, narrow pore size distribution and a low oxygen content of 3%. The study provides an effective insight to recycle PVC from waste PVC and develop a carbon precursor for high performance carbon materials such as CFs and ACFs.     

Distribution Characteristics and Implication of n-alkanes in Soils and Plants in Alpine Meadow

Russian Journal of Ecology - The present study was conducted to investigate the n-alkane composition of typical alpine meadows. Plant and soil samples were collected and analyzed to characterize...     

Carbonization of waste PVC to develop porous carbon material without further activation

Efficient removal of chlorine from PVC achieved by two-stage heat-treatment (280 and 410 degrees C) provided chlorine-free isotropic pitch containing additive. The pitch was stabilized and carbonized into porous carbons with surface areas of approximately 300 m2/g. Resultant porous carbons showed three pore structures of supermicropore, micropore and mesopore. The generation of CO2 from the decomposition of the CaCO3 additive in waste PVC is responsible for the development of porous structures. The surface area of the carbonized product increased after the removal of CaO.     

Fractionation of plutonium in environmental and bio-shielding concrete samples using dynamic sequential extraction

Fractionation of plutonium isotopes (²³⁸Pu, ^239,240Pu) in environmental samples (i.e. soil and sediment) and bio-shielding concrete from decommissioning of nuclear reactor were carried out by dynamic sequential extraction using an on-line sequential injection (SI) system combined with a specially designed extraction column. Plutonium in the fractions from the sequential extraction was separated by ion exchange chromatography and measured using alpha spectrometry. The analytical results show a higher mobility of plutonium in bio-shielding concrete, which means attention should be paid to the treatment and disposal of nuclear waste from decommissioning.