Analysis of Environmental and Socio-economic Determinants Affecting Population Longevity Level at County Level in China

INTRODUCTIONIn recent thirty years, due to the decreasing fertility andincreasing life expectancy, China's population is aging ata very rapid pace and the elderly population size is keepingon growing. During the dramatic aging progress, the oldestold group in China is catching our eyes. More and moreold people of China are becoming the oldest old. Theextremely old population (aged 80 and above) is increasingat 5.1% annually, while the old population above 65 isincreasing at 2.9%, and the…     

基于原代培养背角无齿蚌鳃细胞的镉毒性效应评价

为了探究淡水贝类背角无齿蚌鳃细胞的原代培养途径，并阐释其在评价水体Cd²⁺毒性效应上的潜力，本研究比较了不同酶分解方法（链霉蛋白酶、胰蛋白酶）的鳃细胞存活率差异，并分析了L-15培养基中不同血清浓度（10% FBS、20% FBS）对鳃细胞存活率的影响，细胞置于20℃生化培养箱中培养.进而根据Cd²⁺对鳃细胞的LC₂₅值设定0.0625、0.125、0.25、0.5和1.0 mg·L^-1 5个Cd²⁺理论浓度梯度，对原代培养的鳃细胞进行24 h暴露，分析了细胞活力、总超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和酸性磷酸酶（AcP）的变化特征.结果表明：0.025%链霉蛋白酶在4℃分解16 h的鳃细胞存活率为98.2%±0.2%，显著高于0.25%胰蛋白酶在26℃分解30 min的89.4%±3.5%鳃细胞存活率（p<0.05）；L15培养基加入10% FBS的细胞存活率总体显著高于添加20% FBS的细胞存活率（p<0.05）.在上述较佳的分解和血清浓度组合条件下，细胞培养120 h后，其存活率仍高达90.1%±4.7%.鳃细胞活力随着Cd²⁺浓度的增加而降低，两者之间呈显著的线性负相关（p<0.05）；随着Cd²⁺浓度的增加，SOD和AcP含量总体增加，而CAT含量呈现出"诱导-抑制"的变化趋势.本研究初步建立了较为适宜的背角无齿蚌鳃细胞的原代培养方法，并揭示了其原代培养鳃细胞的细胞活力及SOD、CAT、AcP水平，具有作为评价水环境Cd²⁺毒性/污染的生物指标的潜力.     

液体化工罐区静电产生的原因及防范措施

对液体化工罐区静电产生的原因及可能产生的严重危害性做了详细的分析,并提出了防范措施.     

氮气中二氧化硫气体浓度测量不确定度的评定

采用紫外荧光法测定氮气中的二氧化硫气体浓度的测量不确定度.充分考虑重复测量的重现性、测量仪器的计量性能局限性、标定仪器所用的标准气体等因素对测量的影响,计算氮气中的二氧化硫气体浓度测量合成标准不确定度为0.4.     

浅谈混凝沉淀在炼油污水中的应用

随着国家对环保的重视，为确保处理效果，混凝沉淀技术在一些炼油污水中得到应用，并取得了较好的效果。     

广州市环境监测管理信息化建设中若干问题探讨

以广州市环境监测中心站推进信息化的实践为例，重点对环境监测管理信息化规划、开发和应用3个环节所涉及的信息化进程路线、应用系统开发的需求分析和推广应用等问题进行了一些探讨，提出切合自身的解决思路或办法。     

Simultaneous preconcentration of cadmium and lead in water samples with silica gel and determination by flame atomic absorption spectrometry

A new method that utilizes pretreated silica gel as an adsorbent has been developed for simultaneous preconcentration of trace Cd(II) and Pb(II) prior to the measurement by flame atomic absorption spectrometry. The effects of pH, the shaking time, the elution condition and the coexisting ions on the separation/preconcentration conditions of analytes were investigated. Under optimized conditions, the static adsorption capacity of Cd(II) and Pb(II) were 45.5 and 27.1mg/g, the relative standard deviations were 3.2% and 1.7% (for n = 11), and the limits of detection obtained were 4.25 and 0.60 ng/mL, respectively. The method was validated by analyzing the certified reference materials GBW 07304a (stream sediment) and successfully applied to the analysis of various treated wastewater samples with satisfactory results.     

PHAST软件对孔洞泄漏扩散危险区域的分析

运用PHAST软件研究泄漏孔径、风速、泄漏时间和大气稳定度对泄漏扩散面积的影响。结果表明:扩散面积随着泄漏孔径的增大、风速的增大及泄漏时间的增长而增加;大气越稳定,泄漏扩散面积越大。     

Aerobic granules cultivated and operated in continuous-flow bioreactor under particle-size selective pressure

A novel method based on the selective pressure of particle size （particle-size cultivation method, PSCM） was developed for the cultivation and operation of aerobic granular sludge in a continuous-flow reactor, and compared with the conventional method based on the selective pressure of settling velocity （settling-velocity cultivation method, SVCM）. Results indicated that aerobic granules could be cultivated in continuous operation mode by this developed method within 14 days. Although in the granulation process, under particle-size selective pressure, mixed liquor suspended solids （MLSS） in the reactor fluctuated greatly and filamentous bacteria dominated the sludge system during the initial operation days, no obvious difference in profile was found between the aerobic granules cultivated by PSCM and SVCM. Moreover, aerobic granules cultivated by PSCM presented larger diameter, lower water content and higher specific rates of nitrification, denitrifieation and phosphorus removal, but lower settling velocity. Under long term operation of more than 30 days, aerobic granules in the continuous-flow reactor could remain stable and obtain good chemical oxygen demand （COD）, NH4^＋-N, total nitrogen （TN） and total phosphorus （TP） removal. The results indicate that PSCM was dependent on the cultivation and maintenance of the stability of aerobic granules in continuous-flow bioreactors.     

胞外聚合物磷酸盐形态对生物除磷过程的影响研究

以不同DO条件下污泥龄(SRT)分别为10 d和30 d的两组实验室A/O-SBR反应器活性污泥为研究对象,探讨了胞外聚合物(EPS)磷酸盐形态对生物除磷过程的影响.结果表明,污泥絮体中的磷主要分布于EPS中,PO3-4-P和聚磷酸盐(Poly-P,包括低分子量聚磷酸盐LMW PolyP和高分子量聚磷酸盐HMW Poly-P)是EPS磷的主要形态;EPS对生物除磷的影响明显大于细菌细胞,EPS磷的厌氧降低量和好氧升高量为胞内磷变化量的2.8~6.4倍.EPS中的LMW Poly-P和HMW Poly-P含量均表现厌氧降低和好氧升高的变化规律;对于相同SRT的污泥,中DO(2.5~3.5 mg·L-1)条件较低DO(0.7~1.0 mg·L-1)条件下EPS的LMW Poly-P和HMW Poly-P有更大的厌氧降低量和好氧升高量,对应着更明显的生物除磷过程,说明EPS不仅是生物除磷过程的中转站,而且参与了生物聚磷过程.