排水刚性桩处置可液化倾斜场地的振动台试验研究∗

排水刚性桩将竖向排水体和刚性桩相结合,是一种有效的地基抗液化处理措施。但目前对排水刚性桩在可液化倾斜场地中抗液化侧向变形的性能研究还比较缺乏,制约了其推广与应用。通过振动台试验,开展了可液化倾斜场地中排水刚性桩和普通刚性桩的对比研究,从土体内部动孔压响应、液化土体的流动性质、桩顶水平位移等角度研究了排水刚性桩对可液化倾斜场地的处理效果,并考虑了群桩布置形式的影响。结果表明,排水刚性桩是一种有效的加固可液化倾斜场地的处理措施,可以较好的限制液化土体侧向变形;相同群桩布置形式下,排水刚性桩限制土体流动变形效果优于普通刚性桩,且这种限制效果在坡顶位置更为明显;对于普通刚性桩,群桩梅花形布置形式相对于正方形布置形式能更好的阻止液化土体的流动变形,而对于排水刚性桩,群桩布置形式影响较小。     

北京经济技术开发区典型行业职业卫生管理调查

我国职业卫生工作起步较晚,基础数据匮乏,研究和探讨典型区域典型行业的职业卫生管理现状对今后我国的职业卫生管理发展具有一定的借鉴意义.本文采用调查问卷方法,对北京经济技术开发区机械制造、印刷、汽修、医药、电子5大典型行业职业卫生管理情况进行调查研究.通过数据统计分析,总结得出结论,并进行讨论.     

Bioconcentration study of Xinjunan in zebrafish

An experiment was carried out to determine the acute toxicity and bioconcentration factor of Xinjunan in zebrafish under semi-static test method. The result of the 96-h LC(50) values (0.31 mg/L), at 95% confidence limit, revealed that Xinjunan was highly toxic. Bioconcentration factor after 8 days exposure, 451.0 and 273.2, respectively, at two concentrations, were at medium bioconcentration range. To determine Xinjunan residues in water and fish, a method was developed by using a liquid-liquid distribution and a cationic exchange solid-phase extraction method to extract and clean up Xinjunan in fish, and then using a weak cationic exchange column with gradient elution and second-order mass spectrometry with selected reaction monitoring mode detection. This method found a good linear relationship (r > 0.99), the lowest limit of quantification with a signal-to-noise ratio of 10:1 was 0.02 [Formula: see text]g/L in water and 5 [Formula: see text]g/kg in fish, the recovery ranged from 97% to 109% for water and fish at different levels with a coefficient of variation less than 5%. The accuracy, precision, and lowest limit of detection of the method used for residue analysis of Xinjunan in water and fish can meet environmental exposure monitoring requirements. The results of the acute toxicity and bioconcentration provide a basis for environmental risk analysis of Xinjunan.     

Catalytic activity,selectivity, and stability of co-precipitation synthesized Mn-Ce mixed oxides for the oxidation of 1,2-dichlorobenzene

Environmental Science and Pollution Research - Mn-Ce mixed oxides were prepared using a simple, facile, and high yielding co-precipitation method. The effects of the proportion of Mn/Ce and the...     

医疗废物焚烧炉运行前后5年周边土壤重金属对比分析研究

为研究医疗废物焚烧炉对周边土壤中重金属含量的影响,对某典型焚烧厂周围土壤进行了运行前和运行5年(2007—2012年)后重金属含量的采样分析研究.共采集20个土壤样品、2个飞灰样品,并对其中砷(As)、镉(Cd)、铜(Cu)、汞(Hg)、镍(Ni)、铅(Pb)、锑(Sb)、钒(V)、锌(Zn)共10种重金属的含量进行了测定.结果显示,除Pb外,其余金属元素含量都有不同程度的升高.主成分分析表明,医疗废物焚烧厂并不是该区域土壤中重金属的唯一污染来源,还存在其它潜在污染源.健康风险评估结果显示,砷(As)在非致癌及致癌风险评估中都明显超标,必须严格控制砷排放,降低砷在环境中的含量.     

Effect of ammonium sulfate and urea on PCDD/F formation from active carbon and possible mechanism of inhibition

The effect of ammonium sulfate （（NH4）2SO4） and urea （CO（NH2）2） on polychlorinated dibenzo-p-dioxin and dibenzofuran （PCDD/F） formation from active carbon was investigated in this study. Both additives could significantly inhibit PCDD/F formation, and PCDD/F （TEQ） generation was reduced to 98.5% （98%） or 64.5% （77.2%） after 5% （NH4）2S04 or CO（NH2）2 was added into model ash, respectively. The inhibition efficiency of PCDDs was higher than the value of PCDFs, however, the reduction of PCDD/F yield was mainly from PCDFs decreasing. In addition, the solid-phase products were reduced more than the gas-phase compounds by inhibitors. By the measurement of chlorine emission in the phase of ion （Cl[Cl^-]） and molecule gas （Cl[Cl2]）, it was observed that both Cl[Cl^-] and Cl[Cl2] were reduced after inhibitors were added into ash. Cl[Cl2] was reduced to 51.0% by urea addition, which was supposed as one possible mechanism of PCDD/F inhibition.     

活性炭碘值的测量不确定度评定

本文依据GB/T7702.7-2008,对活性炭碘值测量过程中的不确定度分量进行了分析和评定,定量表征了测量结果的可信程度。测量不确定度主要来源于碘标准滴定溶液、滴定过程、重复性引入的不确定度,从而对此测量方法的准确性进行了科学的判断。     

医疗废物典型物料热解过程中无机氯的气相迁移规律

在温度为600～900℃、氮气气氛下.用管式炉实验台对医疗废物典型组分--棉花和聚丙烯(PP)进行了快速热解实验.为了研究氯的迁移规律,对物料添加了适量的盐水,结果表明,医疗废物典型组分和NaCl溶液混合热解的过程中Cl的析出随着热解温度、热解时间和物料与Cl元素质量配比的改变而改变.研究发现,Cl的析出峰在以棉花为物料时出现在800℃,而用PP为物料时出现在700℃;随着热解时间的变化,Cl的析出率呈现不规律的变化:700℃棉花热解实验中,热解时间5min时.Cl的析出率只有0.0002,在10min时,析出率达到了0.0003;而在800℃棉花的热解实验中,5min时Cl的析出率为0.00062.而随着热解时间的增加,10min时,Cl的析出率却降到了0.00045.同时还发现,随着Cl元素含量的增加.其析出率也在提高,当Cl和物料质量比值增加1倍时,Cl的析出率也随着温度的变化相应的增加2～4倍.     

原油储罐雷击危害及对策

介绍了雷电形成、分类和各种危害,分析了目前原油储罐在防雷方面存在的问题,提出了非金属原油罐、金属原油罐和浮顶原油罐预防雷击的措施.