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61.
介绍了起重机用各种缓冲器的性能和缓冲原理,比较了它们各自的特点,指出了在选择使用时应考虑的几个方面的问题。 相似文献
62.
中国加入世贸组织对环境保护的影响 总被引:5,自引:0,他引:5
随着中国加入世界贸易组织(下称WTO)日益临近,入世对于我国经济和环境的影响越来越成为人们关注的焦点.本文拟对此作些探讨. 相似文献
63.
Changhong Chen Yarong Peng Hongli Wang Qian Wang Shengao Jing Jingyu An Yaqin Gao Cheng Huang Rusha Yan Haixia Dai Tiantao Cheng Qiang Zhang Meng Li Jianlin Hu Zhihao Shi Li Li Shengrong Lou Shikang Tao Qinyao Hu Jun Lu 《环境科学学报(英文版)》2023,35(2):794-805
Both concentrations and emissions of many air pollutants have been decreasing due to implement of control measures in China, in contrast to the fact that an increase in emissions of non-methane hydrocarbons (NMHCs) has been reported. This study employed seven years continuous NMHCs measurements and the related activities data of Shanghai, a megacity in China, to explore evolution of emissions and effectiveness of air pollution control measures. The mixing ratio of NMHCs showed no statistical interannual changes, of which their compositions exhibited marked changes. This resulted in a decreasing trend of ozone formation potential by 3.8%/year (p < 0.05, the same below), which should be beneficial to ozone pollution mitigation as its production in Shanghai is in the NMHCs-limited regime. Observed alkanes, aromatics and acetylene changed by +3.7%/year, -5.9%/year and -7.4%/year, respectively, and alkenes showed no apparent trend. NMHCs sources were apportioned by a positive matrix factorization model. Accordingly, vehicular emissions (-5.9%/year) and petrochemical industry emissions (-7.1%/year) decreased significantly, but the decrease slowed down; significant reduction in solvent usage (-9.0%/year) appeared after 2010; however, emissions of natural gas (+12.6%/year) and fuel evaporation (with an increasing fraction) became more important. The inconsistency between observations and inventories was found in interannual trend and speciation as well as source contributions, emphasizing the need for further validation in NMHCs emission inventory. Our study confirms the effectiveness of measures targeting mobile and centralized emissions from industrial sources and reveals a need focusing on fugitive emissions, which provided new insights into future air policies in polluted region. 相似文献
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基于某露天矿坑飏尘防治用风障工程,建立数学物理模型进行数值模拟探究风障(含人工风障和防护林带)对大型露天矿坑飏尘的防护效果。运用计算流体动力学软件Fluent并选取高雷诺数下k-ε模型用SIMPLE算法进行计算,得到风障周围的流场及压力场的分布,从而分析人工风障和防护林带后沿流水平距离变化时不同高度间相对风速的变化,得出位于人工风障后位置越低,防护效果越强,当y=0.2 h时,约为初始风速的50%,且当气流深入林带后其防护效果增强,在进入后水平距离4 h’时,相对风速约为初始风速的30%。 相似文献
66.
Bi2WO6催化剂的合成和表征及其光催化活性 总被引:1,自引:1,他引:0
以Bi(NO3)3和Na2WO4为原料,采用水热法合成了可见光催化剂Bi2WO6,并采用X射线衍射仪和BET法对其进行了表征。考察了合成温度、Bi2WO6加入量、邻氯苯酚(2-CP)浓度、溶液pH等对2-CP光催化降解效果的影响。实验结果表明:在加入140℃下合成的Bi2WO6催化剂1g/L、原始pH(pH=5.85)、可见光光照210min的条件下,对质量浓度为20mg/L的2-CP溶液进行处理,2-CP去除率最高为97.2%;添加少量H2O2对2-CP的降解有促进作用。 相似文献
67.
流化床煤部分气化、热解脱硫过程试验研究 总被引:1,自引:0,他引:1
在一小型流化床试验台上进行煤部分气化、热解脱硫过程的试验研究.该试验系统由启动燃烧室、流化床本体、灰循环子系统、加料子系统、排渣子系统、蒸汽发生子系统以及测量控制子系统等组成.流化床本体直径为0.1m,高为4.22m,采用烟气夹套加热的方法维持床体温度.试验结果如下:当风煤质量比从2.5增加到5.0时,脱硫效率先增加后降低;当汽煤比从0.45增加到0.63时,脱硫效率也是先增加后降低;钙硫比增加,脱硫效率增加;床温升高,脱硫效率增加.与此同时,还研究了石灰石种类对脱硫效率的影响,以及气化、热解效率与脱硫效率间的相互关系. 相似文献
68.
Wang Zhichao Qin Yiming Li Weiping Yang Wenhuan Meng Qing Yang Jianlin 《Environmental Chemistry Letters》2019,17(4):1821-1830
Environmental Chemistry Letters - Microplastic pollution has been widely studied in the marine environment, but is much less explored in terrestrial waters, notably in China. Therefore, we studied... 相似文献
69.
Dechao Hu Zhixin Jia Jianlin Li Bangchao Zhong Weiwen Fu Yuanfang Luo Demin Jia 《Journal of Polymers and the Environment》2018,26(4):1311-1319
Waste printed circuit boards (WPCB) nonmetals were firstly recycled as reinforcing filler in a kind of novel room temperature cured unsaturated polyester (UPE) composites. The compositions and characteristics of WPCB nonmetals were detailly analyzed by SEM, FTIR, TGA and Py-GCMS, and the effects of the content of WPCB nonmetals on the mechanical performance and thermal behaviors of UPE composites were also systematically studied. Results suggested that UPE composites incorporated with WPCB nonmetals at appropriate content showed superior tensile strength, flexural strength and heat distortion temperature than UPE matrix. Based on the analysis of thermal degradation kinetic, the thermal stability of UPE composites were significantly enhanced by the incorporation of WPCB nonmetals. The highlight of this work lies in the fact that high-valued utilization of WPCB nonmetals is realized in room temperature cured UPE matrix, which may not only achieve favorable economic and social benefits, but also open up new opportunities for the preparation of high performance plastic composites. 相似文献
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