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651.
参考了前人对于拆迁建筑垃圾的研究,根据南京市相关统计数据,估算出1998-2009年间南京城市房屋拆迁建筑垃圾年产生量,并比较了相关数据,得出估值合理。估算结果显示南京市房屋拆迁建筑垃圾年产生量波动较大,但变化趋势大体为上升。影响因素分析显示南京市GDP与房屋拆迁建筑垃圾年产生量1998-2003年间具有高度正相关性,2004-2009年正相关性减弱;市民法律意识的提高使得南京市房屋拆迁趋于合理,间接减缓了房屋拆迁建筑垃圾年产生量的增长趋势;房屋拆迁政策的制定以及修订、社会事件对南京市房屋拆迁建筑垃圾年产生量有短期的影响。最终得出结论随着城市房屋拆迁决策系统的发展,南京市房屋拆迁建筑垃圾产生量将趋于合理。  相似文献   
652.
CASS工艺在处理生活废水过程中具有运行灵活特点,根据进出水水质及污水水量的变化灵活调整工艺运行各阶段长短,实现不同的处理目标,达到经济运行的目的。当进水COD和NH3-N浓度较高时,通过延长曝气时间,合理调整其他阶段时间,来实现达标排放,具有抗冲击负荷能力强优势。  相似文献   
653.
Distinct from the case with width-dominated shallow wetland flows, the longitudinal evolution of contaminant concentration in the most-typical pattern of wetland as dominated by free-water-surface-effect is characterized by a multi-scale analysis in the present study. An environmental dispersion model for the evolution of the mean concentration is deduced as an extension of Taylor’s classical formulation by Mei’s multi-scale analysis. Corresponding environmental dispersivity is found identical to that determined by the method of concentration moments.  相似文献   
654.
利用1980-2014年黑龙江省15个玉米农业气象观测站的资料,基于中华人民共和国玉米冷害评估气象行业标准规定的≥10℃积温距平指标,对玉米3个发育关键时期出苗-七叶期、出苗-抽雄期、出苗-乳熟期的冷害进行动态判识,并分析其时空演变特征,同时应用统计方法分析积温距平与玉米实际单产的关系。研究结果表明:11980-2014年间,玉米3个发育时期内的冷害年数在7~17年之间,冷害发生对气候变暖趋势具有明显的响应;21980-2014年间研究区玉米3个发育时期冷害的发生随时间呈减少趋势,1990年代中期以前为高发期,之后冷害发生频率下降。空间分布上,冷害呈现北多南少特征,并具有群发性、区域性和局地性特点;31980-2014年间,研究区玉米3个发育时期的≥10℃积温距平具有16年左右的周期变化,总体表现为1995年以前偏冷,之后偏暖,其中玉米出苗-七叶期积温距平存在最近几年偏冷的趋势;4研究区67%的站点≥10℃积温距平与玉米实际单产存在显著或极显著的相关关系,积温距平为100~200℃·d,利于玉米高产;5≥10℃积温距平指标赋予玉米冷害判识指标生物学和农学意义,充分表征玉米不同发育时期热量需求与供给的关系,有效提升作物冷害判识的客观性。  相似文献   
655.
以活性红KE-3B为例,考察了中高温条件下盐度、VFAs(挥发性脂肪酸)、污泥的吸附等对其厌氧脱色的影响,从产气量和生物气组分来探讨活性红KE-3B厌氧脱色的形式和程度,并对活性红KE-3B的厌氧脱色机理作初步探讨.结果显示,高温更有利于活性红KE-3B的脱色,脱色率可以达到98%以上,维持高脱色率的最高盐度为600mmol·L-1,并且在脱色过程中,没有发现活性红KE-3B被矿化,其主要脱色形式为初级降解.  相似文献   
656.
太原市PM10及其污染源中碳的同位素组成   总被引:1,自引:0,他引:1       下载免费PDF全文
通过采集太原市PM10及其主要源(煤烟尘、机动车尾气尘、土壤风沙尘)样品,结合离线分步加热氧化法和同位素质谱仪测定了颗粒物中有机碳(OC),元素碳(EC)和总碳(TC)的同位素组成, 并探讨了太原市PM10中碳的来源.结果表明,太原市冬季、春季PM10中OC、EC和TC的碳同位素组成分别是-34.7‰、-23.5‰、-23.9‰和-30.5‰、-23.1‰、-23.9‰; 煤烟尘中OC、EC和TC的碳同位素组成分别是-26.5‰、-23.2‰、-23.6‰,土壤风沙尘分别为-24.6‰、-14.1‰、-17.3‰,汽油车和柴油车尾气尘分别为-27.7‰、-25.5‰、-27.0‰和-25.7‰、-24.3‰、-24.8‰. EC和TC的同位素组成是区分土壤风沙尘较好的标识指标,TC的同位素组成是汽油车尾气尘较好的标识指标;利用二元复合计算公式结果显示土壤风沙尘中OC、EC占TC的百分含量分别为30%、70%;煤烟尘中OC、EC占TC的百分含量分别为11%、89%;汽油车尾气尘中OC、EC占TC的百分含量分别为78%、22%,柴油车尾气尘中OC、EC占TC的百分含量分别为36%、64%;太原市PM10中的TC和EC主要来源于煤烟尘,OC少部分来源于机动车尾气排放,另外还有其他的重要贡献源.  相似文献   
657.
Whether plant coexistence can reduce the impacts of lead (Pb) on crops in agroecosystems has not been well understood. We conducted a factorial experiment to investigate the effects of weeds coexisting with maize (Zea mays L.) on Pb accumulation in maize and soil microbes at two Pb levels (ambient and 300 mg/kg). Elevated Pb tended to increase the Pb concentration in maize and decreased soil microbial activity (indicated by the average well color development, AWCD), functional group diversity, as well as arbuscular mycorrhizal (AM) colonization and vesicle number of maize. Compared to the monoculture, weeds coexisting with maize reduced the Pb concentrations in the root, leaf, sheath and stem of maize at both seedling and mature stages. In maize-weed mixtures, soil microbial activity and functional group diversity tended to increase for both Pb treatments relative to the monoculture. Furthermore, principal component analysis revealed that the soil microbial community structure changed with the introduction of weeds. The highest Pb accumulation in weeds occurred for the elevated Pb treatment in a three species mixture. The results suggest that multiple plant species coexistence could reduce lead accumulation in crop plants and alleviate the negative impacts on soil microbes in polluted land, thereby highlighting the significance of plant diversity in agroecosystems.  相似文献   
658.
A TiO2 thin film electrode deposited on porous nickel net (TiO2/Ni) was prepared by the sol-gel method, and the surface morphology, crystal structure features and the grain size were characterized by Field emission scan electron microscopy (FESEM) and X-ray diffraction (XRD). The photoelectrocatalytic system was set up using a UV high-pressure mercury lamp as the light source, TiO2 coated on foamed nickel as photo anode, Pt sheet as counter electrode and the pesticide dipterex in synthetic wastewater. Various factors that influence the photoelectrocatalytic decomposition of dipterex pesticide have been studied, such as degradation time, the type of electrolyte, current density, original pH value and different degradation methods. The prepared catalysts were employed to photoelectrocatalytically degrade the pesticide dipterex under UV irradiation, comparing the results with photocatalytic degradation and electrochemical oxidation. The results indicated that under the optimal conditions of 0.02 mol/L NaCl as the supporting electrolyte, current density = 2.5 mA/cm2, pH 6.0 and dipterex pesticide 40 mg/L, and reaction time 2 hr, dipterex chemical oxygen demand (COD) removal rate and organophosphorous conversion of up to 82.6% and 83.5% were achieved, respectively. The method of photoelectrocatalytic degradation is more efficient than photocatalysis and electrochemical oxidation. The possible roles of the electrolytes on the reactions and probable mechanisms were also discussed.  相似文献   
659.
So far, very little is known about mercury stress-induced intercellular metabolic changes in rice roots at the proteome level. To investigate the response of rice roots to mercury stress, changes in protein expression in rice roots were analyzed using a comparative proteomics approach. Six-leaf stage rice seedlings were treated with 50 μmol/L HgCl2 for 3 hr; 29 protein spots showed a significant changes in abundance under stress when compared with the Hg2+-tolerant rice mutant and wild type (Zhonghua 11). Furthermore, all these protein spots were identified by mass spectrometry to match 27 diverse protein species. The identified proteins were involved in several processes, including stress response, redox homeostasis, signal transduction, regulation and metabolism; some were found to be cellular structure proteins and a few were unknown. Among the up-regulated proteins, OsTCTP (translationally controlled tumor protein) was chosen to perform hetereologous expression in yeast which was presumed to participate in the Hg2+ tolerance of rice, providing evidence for its role in alleviating Hg2+ damage. Among the many tests, we found that OsTCTP-overexpressed yeast strains were more resistant to Hg2+ than wild-type yeast. Thus, we propose that OsTCTP contributes to Hg2+ resistance. Here we present, for the first time, the functional characterization of OsTCTP in connection with Hg2+ stress in plants.  相似文献   
660.
运用市场机制减少温室气体排放,是欧盟积极应对气候变化,实现其减排承诺的重要手段。本文从德国排放交易制度建立的背景和法律保障、德国排放交易管理机构的职能、温室气体排放交易的实施程序和额度分配、以及交易的质量保证等方面,详细介绍和分析德国温室气体排放交易管理体系。并在此基础上进一步阐述了其对我国温室气体排放交易管理的启示,并结合我国污染物普查及总量控制等经验,从法制建设、总量控制、交易管理、机构建设等方面提出了相应意见和建议。  相似文献   
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