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801.
采用批式发酵法对厌氧产氢菌株Bacteria.P利用葡萄糖发酵,在底物浓度、初始pH值、接种比例等不同培养条件下的产氢能力进行了研究。结果表明:专性厌氧菌P是一种高效产氢的菌株,在葡萄糖质量浓度为10 g/L、初始pH为6.0、接种比例为1∶20时,发酵气体总产量和细胞干重达到最大值,分别为485 mL和0.836 g/L。 相似文献
802.
结合环境监测仪器设备的特点,着重阐述了从设备分类、量值溯源、维修维护等几方面环境监测设备的常规管理方法,并对其现代化的管理进行了探索。 相似文献
803.
804.
垃圾渗滤液是垃圾填埋过程中产生的一种有机浓度高、成分复杂的污水,对周边生态环境和人们身心健康影响极大。本文详细介绍了垃圾渗滤液的水质特征及国内外各类控制技术,并进行了对比分析,提出是源头控制重点,处理是保障的污染控制新思路。 相似文献
805.
为了研究条形荷载作用下三明治形混合填土方式对加筋土挡墙变形特性的影响,采用 FLAC3D建立了数值计算模型,分析了三明治形加筋土挡墙的黏土弹性模量 E1、砂土弹性模量 E2、砂土厚度 d、筋材长度 L 以及荷载距面板距离 D 对挡墙变形特性的影响。结果表明:相对于加筋黏土挡墙,三明治形加筋土挡墙变形大幅减小,减少其墙顶沉降约 32%,减少面板位移约 44%;其土压力分布规律为墙后水平土压力大体上随填土深度的增加而增大;适当增大黏土弹性模量有利于减小挡墙顶面差异沉降;砂土存在一个最优弹性模量,使得面板水平位移最小;三明治形加筋土挡墙存在一个最优砂土厚度,使得三明治加筋土挡墙工作性能最佳;当 L/H≥0.7 时,继续增加筋材长度或当 D/H≥0.3 时,继续增大荷载距面板距离对挡墙影响相对较小。 相似文献
806.
The brominated products, formed in chlorination treatment of benzophenone-4 in the presence of bromide ions, were identified, and the formation pathways were proposed.Under disinfection conditions, benzophenone-4 would undertake electrophilic substitution generating mono- or di-halogenated products, which would be oxidized to esters and further hydrolyzed to phenol derivatives. The generated catechol intermediate would be transformed into furan-like heterocyclic product. The product species were p H-dependent,while benzophenone-4 elimination was chlorine dose-dependent. When the chlorination treatment was performed on ambient water spiked with benzophenone-4 and bromide ions, most of brominated byproducts could be detected, and the acute toxicity significantly increased as well. 相似文献
807.
Experimental study on filtration and continuous regeneration of a particulate filter system for heavy-duty diesel engines 总被引:1,自引:0,他引:1
This study investigated the filtration and continuous regeneration of a particulate filter system on an engine test bench, consisting of a diesel oxidation catalyst(DOC) and a catalyzed diesel particulate filter(CDPF). Both the DOC and the CDPF led to a high conversion of NO to NO2 for continuous regeneration. The filtration efficiency on solid particle number(SPN) was close to100%. The post-CDPF particles were mainly in accumulation mode. The downstream SPN was sensitively influenced by the variation of the soot loading. This phenomenon provides a method for determining the balance point temperature by measuring the trend of SPN concentration. 相似文献
808.
Qinqin Lou Yinfeng Zhang Dongkai Ren Haiming Xu Yaxian Zhao Zhanfen Qin Wuji Wei 《环境科学学报(英文版)》2014,26(10):2084-2094
Considering some advantages of Rana nigromaculata as an experimental species, we propose that this species, like Xenopus laevis, could be used to assay thyroid hormone(TH) signaling disrupting actions. To validate the utilizability of R. nigromaculata, we investigated the responsiveness of R. nigromaculata to a TH receptor(TR) agonist(T3) and antagonist(amiodarone) by analyzing expression, based on characterizing TR cDNA and developmental expression patterns. With high levels of identity with the corresponding genes in X. laevis, both TRα and TRβ in R. nigromaculata exhibited roughly similar developmental expression patterns to those of X. laevis, in spite of some species-specific differences. Both TRα and TRβ expression had greater changes in the liver and intestine than in the tail and brain during metamorphosis. T3 exposure for 2 days induced more dramatic increases of TRβ expression in stage 27 than in stage34 tadpoles but not in stage 42 tadpoles, showing that the responsiveness of R. nigromaculata to TH decreased with development and disappeared at the onset of metamorphic climax.Corresponding to greater changes of TRβ expression in the liver and intestine than in the tail and brain during metamorphosis, the liver and intestine had higher responsiveness to exogenous T3 than the tail and brain. Amiodarone inhibited T3-induced TRβ expression. Our results show that R. nigromaculata can be used as a model species for assaying TH signaling disrupting actions by analyzing TRβ expression, and intestine tissues at stage 27 are ideal test materials due to high responsiveness and easy accessibility. 相似文献
809.
Hong Zhao Yunshan Ge Tiezhu Zhang Jipeng Zhang Jianwei Tan Hongxin Zhang 《环境科学学报(英文版)》2014,26(10):2027-2033
The alteration and formation of toxic compounds and potential changes in the toxicity of emissions when using after-treatment technologies have gained wide attention. Volatile organic compound(VOC), carbonyl compound and particle-phase polycyclic aromatic hydrocarbon(PAH) emissions were tested at European Steady State Cycle(ESC) to study unregulated emissions from a diesel engine with a fuel-borne catalyst and diesel particulate filter(FBC–DPF). An Fe-based fuel-borne catalyst was used for this study. According to the results, brake specific emissions of total VOCs without and with DPF were 4.7 and4.9 mg/kWh, respectively, showing a 4.3% increase. Benzene and n-undecane emissions increased and toluene emission decreased, while other individual VOC emissions basically had no change. When retrofitted with the FBC–DPF, total carbonyl compound emission decreased 15.7%, from 25.8 to 21.8 mg/kWh. The two highest carbonyls, formaldehyde and acetaldehyde, were reduced from 20.0 and 3.7 to 16.5 and 3.3 mg/kWh respectively. The specific reactivity(SR) with DPF was reduced from 6.68 to 6.64 mg/kWh. Total particle-phase PAH emissions decreased 66.4% with DPF compared to that without DPF. However, the Benzo[a]pyrene equivalent(BaPeq) with DPF had increased from 0.016 to 0.030 mg/kWh.Fluoranthene and Pyrene had the greatest decrease, 91.1% and 88.4% respectively. The increase of two- and three-ring PAHs with DPF indicates that the fuel-borne catalyst caused some gas-phase PAHs to adsorb on particles. The results of this study expand the knowledge of the effects of using a particulate filter and a Fe-based fuel-borne catalyst on diesel engine unregulated emissions. 相似文献
810.
Understanding the efectiveness of national air pollution controls is important for control policy design to improve the future air quality in China. This study evaluated the efectiveness of major national control policies implemented recently in China through a modeling analysis. The sulfur dioxide(SO2) control policy during the 11th Five Year Plan period(2006–2010) had succeeded in reducing the national SO2emission in 2010 by 14% from its 2005 level, which correspondingly reduced ambient SO2and sulfate(SO4 2) concentrations by 13%–15% and 8%–10% respectively over east China. The nitrogen oxides(NOx) control policy during the 12th Five Year Plan period(2011–2015) targets the reduction of the national NOx emission in 2015 by 10% on the basis of 2010. The simulation results suggest that such a reduction in NOx emission will reduce the ambient nitrogen dioxide(NO2), nitrate(NO3), 1-hr maxima ozone(O3) concentrations and total nitrogen deposition by 8%, 3%–14%, 2% and 2%–4%, respectively over east China. The application of new emission standards for power plants will further reduce the NO2, NO3, 1-hr maxima O3concentrations and total nitrogen deposition by 2%–4%, 1%–6%, 0–2% and 1%–2%, respectively. Sensitivity analysis was conducted to evaluate the inter-provincial impacts of emission reduction in Beijing-Tianjin-Hebei and the Yangtze River Delta, which indicated the need to implement joint regional air pollution control. 相似文献