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371.
通过对莴笋叶2种处理吸附甲醛,得出简便高效的碱热烫处理,并采用二次正交旋转回归组合对其优化,得出煮沸时间25 min、水浴温度80℃、水浴时间2.5h,莴笋叶渣对甲醛吸附率可达37.05%,实测值36.4%,二者吻合.通过与活性炭、硅藻纯吸附效果比较,优化处理莴笋叶渣与硅藻纯吸附效果相当,均优于活性炭.电镜观测知优化莴笋叶渣与活性炭、硅藻纯均具粗糙、皱褶、疏松结构,傅里叶红外光谱分析出-C=C-基团在甲醛吸附中起主要作用.  相似文献   
372.
Spatial variability and temporal trends in concentrations of the organochlorine pesticides (OCPs), hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), in surface soils around Beijing Guanting Reservoir (GTR) were studied in 2003 and 2007. Concentrations of the two OCPs in soils around GTR were generally less than reference values set by the Chinese government for the protection of agricultural production and human health. Among the OCPs, β-HCH and p, p′-DDE were the two predominant compounds. This result indicates that the HCH and DDT residues in soils were primarily from historical use. Based on kriging, a spatial distribution of HCH and DDT around the GTR was observed. Spatial variability indicated how HCH and DDT had been applied and been distributed in the past. Between 2003 and 2007, concentrations of HCH and DDT decreased more rapidly in orchard soils than those in fallow soils.  相似文献   
373.
如东县垃圾、粪便无害化处置场二期工程设计   总被引:1,自引:1,他引:0  
洪征  耿震 《环境工程》2010,28(1):85-87
介绍了如东县垃圾、粪便无害化处置场二期工程概况及主要设计内容。在设计中针对当地特殊的气候条件和地质特征,因地制宜,优化设计,旨在提高工程经济性及实用性。  相似文献   
374.
ABSTRACT: Watersheds above the Miyun reservoir, a principal source of surface water for Beijing, are designated to be managed for water production, but under the principle of multiple use. Because of the scarcity of arable land, these watersheds cannot be managed only for drinking water. Efforts are under way to reduce sediment delivery, improve the quality of water entering Miyun reservoir, and improve the welfare of watershed inhabitants. An economic appraisal of a watershed management project for the 3,298‐ha Shixia watershed above the Miyun reservoir, indicates a 24 percent economic rate of return on the investment made in the project. The net present value (NPV) of the project, calculated at a discount rate of 10 percent, is approximately US$3.49 million. Sensitivity analyses indicate that a doubling of labor costs lowers the NPV to US$2.07 million and a 10 percent decrease in benefits lowered the NPV to US$2.87. It is concluded that the implementation of conservation practices on the Shixia Demonstration Watershed represent an economically efficient use of resources.  相似文献   
375.
以北京动物园的地表水为例,利用引进的海藻提取物EC lean生物工程技术对富营养化地表水进行处理试验研究。试验结果表明:应用此项技术有效降低了水体的浊度、COD和BOD5,水体脱氮降磷明显,藻类细胞密度下降,水体富营养化得到控制,减轻了“水华”藻类的危害。此技术在北京动物园富营养化水体的治理上表现出明显的应用效果。  相似文献   
376.
基于环保检测数据,提出“里程-车龄”曲线用以获取满足“车辆类型-燃料种类-排放标准”三级分类的精细化年均行驶里程.使用《道路机动车大气污染物排放清单编制技术指南(试行)》推荐值、车辆类型均值、“里程-车龄”曲线3种方式获取年均行驶里程并分别建立排放清单,发现年均行驶里程的本地化与精细化可以极大降低行驶里程不确定性对排放清单准确性的影响.采用精细化年均行驶里程,计算得到青岛市2017年机动车CO、VOCs、NOx、PM10、NH3和SO2的排放量分别为7.07,1.14,2.84,0.10,0.08和0.08万t.分析排放构成可知,老旧车淘汰在当前仍可作为青岛市机动车排放治理的有效举措.结合路网信息与交通数据,得到0.01°×0.01°高时空分辨率网格化排放清单.结果表明,青岛市机动车排放分布在不同时段变化明显.以NOx为例,排放的早晚高峰分别出现在8:00与17:00,占到了全天总排放的8.17%和7.53%.同时,排放分布存在着空间异质性,排放从城市中心至边缘呈逐渐降低趋势,沿高速路呈明显带状分布.  相似文献   
377.
探讨草甘膦亚慢性染毒对雄性大鼠睾酮合成的影响。雄性SD大鼠按体重随机分为对照组(0 mg·kg~(-1))、低剂量组(50 mg·kg~(-1))、中剂量组(200 mg·kg~(-1))和高剂量组(800 mg·kg~(-1)),连续灌胃染毒,第4、8和12周时分别处死一批动物,采集血液和脏器。放射免疫分析法检测大鼠血清中卵泡刺激素(follicle stimulating hormone,FSH)、黄体生成素(luteinizing hormone,LH)、睾酮(testosterone,T)、雌二醇(estradiol,E2)水平; HE染色法(苏木精-伊红染色法)观察睾丸病理学变化;免疫组化法检测3β-羟基类固醇脱氢酶(3beta-hydroxysteroid dehydrogenase,3β-HSD)、类固醇激素合成急性调节蛋白(steroid synthesis of acute regulatory protein,St AR)、细胞色素P450胆固醇侧链裂解酶(cytochrome P450 cholesterol side chain lyase,P450scc)和17β-羟基类固醇脱氢酶(17beta-hydroxysteroid dehydrogenase,17β-HSD)蛋白表达水平。随染毒剂量和时间的增加,大鼠血清FSH和T水平呈下降趋势,第12周高剂量组FSH水平明显低于对照组(P0.05),第8周和第12周高剂量组T水平明显低于对照组(P0.05),LH和E2水平各组间无统计学差异(P0.05)。组织病理学可见中、高剂量组睾丸生精小管、生精细胞、间质区结构被破坏。随草甘膦染毒剂量的增加,St AR和P450scc蛋白表达水平与对照组相比显著下降(P0.05),3β-HSD和17β-HSD蛋白表达水平在各组间无差异(P0.05)。草甘膦能降低血清T水平,抑制T合成相关蛋白St AR和P450scc的表达,干扰T的合成过程,具有雄性生殖毒性作用。  相似文献   
378.
Wang  Jing  Geng  Yan  Zhao  Qiuna  Zhang  Yin  Miao  Yongtai  Yuan  Xumei  Jin  Yuxi  Zhang  Wen 《Environmental Modeling and Assessment》2021,26(4):529-541

With the increasingly serious problem of surface water environmental safety, it is of great significance to study the changing trend of reservoir water quality, and it is necessary to establish a water quality prediction and early warning system for the management and maintenance of water resources. Aiming at the problem of water quality prediction in reservoirs, a CA-NARX algorithm is designed, which combines the improved dynamic clustering algorithm with the idea of machine learning and the forward dynamic regression neural network. The improved dynamic clustering algorithm is used to classify the eutrophication degree of waterbodies according to the total phosphorus and total nitrogen content. Considering four meteorological factors, air temperature, water temperature, water surface evaporation, and rainfall, synthetically for each water quality condition, the total phosphorus and total nitrogen in the waterbody are forecasted by an improved forward NARX dynamic regression neural network. Based on this, the CA-NARX prediction algorithm can realize short period water quality prediction. Compared with the traditional support vector regression machine model, improved GA-BP neural network, and exponential smoothing method, the CA-NARX model has the least prediction error.

  相似文献   
379.
China will set up a national carbon emissions trading market by the end of 2017, which is initially open to individual investors from the initial market for business and institutional investors. In this article, the main influencing factors and mechanism of individual participation in carbon trading market are studied by establishing multiple linear regression model. The study found that age, education level, length of account opening time, and risk attitude are the main factors influencing the participation of individual investors. Environmental awareness and environmental impact are less affected; information transparency and transaction risk also have an impact on the degree of individual investor participation; investment experience does not affect the participation of individual investors in the carbon trading market.  相似文献   
380.
Environmental Science and Pollution Research - Waste electrical and electronic equipment (WEEE) contains both toxic and valuable materials. Due to rapid development of information and communication...  相似文献   
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