坡缕石黏土污泥对水相中亚甲基蓝吸附研究

利用坡缕石黏土污泥(从木质素磺酸钠废水中得到)和酸化的坡缕石黏土(1mol/L盐酸)作为吸附剂对水相中的亚甲基蓝进行吸附研究,并利用透射电镜(TEM)、红外光谱(FT-IR)、X-射线衍射(XRD)及Zeta电位分析对两种吸附剂的结构及表面电性进行了表征.结果表明:当吸附剂用量为10mg,温度为30℃时,1mol/L盐酸酸化的坡缕石黏土最大吸附量为97.50mg/g,坡缕石黏土污泥最大吸附量为98.7mg/g.选取坡缕石黏土污泥作为最佳吸附剂,对污泥吸附亚甲基蓝的吸附等温线、吸附热力学及吸附动力学模型进行了研究,结果显示:此吸附过程为自发吸热过程,吸附等温线更符合Langmuir模型,吸附动力学符合准二级动力学模型.     

Crystallization and X‐ray structure of 3,3’,4‐trichlorobiphenyl (PCB 35)∗

A method for the preparation of single crystals of PCB 35 suitable for single crystal X‐ray structure determination was developed. This method has already been proven suitable for 2,4'‐dichlorobiphenyl and may prove useful for other PCBs or related compounds. The crystals of PCB 35 are orthorhombic, spacegroup P2₁22₁ (a= 10.665(8), 6 = 3.825(3), c= 14.086(9) Å) and the structure was refined to R = 0.094 for 156 unique observed reflections and 43 parameters. Although the crystals were of poor quality, the structure determination unequivocally confirmed the substitution pattern of the biphenyl moiety by Cl atoms inferred previously from spectroscopic methods. The dihedral angle between the planes of the two phenyl rings is 33(2)°.     

Assessment of land degradation and its impact on crop production in the Dry Zone of Myanmar

Land degradation in terms of soil degradation is a major environmental issue posing threat to sustainable livelihood in the semi-arid region of Central Myanmar. However, the studies on soil degradation status and its impacts in this region are very scanty. The objective of this study was to determine the impact of land degradation on crop production both in terms of area and yield in the Dry Zone of Myanmar. Remote sensing and geographic information system-based modelling was utilized to assess and map soil erosion rates. Household survey was conducted to understand the causes of land degradation and its impacts on crop productivity and livelihoods. It has been found out that the current rate of soil erosion ranged from 0 to 114 t ha^–1 yr^–1, and that the average rate of soil erosion increased from 14.2 to 54.6 t ha^–1 yr^–1 over a period from 2000 to 2012. The major types of land degradation were physical and chemical soil degradation. Farmers identified topographic condition, soil types, improper crop management practices and climatic factors as the main causes of soil erosion. The observed crop yields of monsoon rice, groundnut, sesame and cotton in the highly degraded area were 3–12 times lower compared with the yields of these crops grown in less degraded area. Livelihoods of the farmers in the high-degraded area were affected by crop yield reduction, increased cultivation cost and increased uncultivable land area. The impact of land degradation on crop production was dependent on the severity of degradation. This suggests that advanced conservation measures are immediately required and the supportive policy strategies need to be implemented to educate farmers and to strengthen extension services for sustainable land management in the Dry Zone of Myanmar.     

转野生荠菜凝集素基因棉花对赤子爱胜蚓的影响

在实验室条件下分别给赤子爱胜蚓(Eisenia foetida)饲喂在自然状况下可能接受的棉叶最高添加量和2倍最高添加量的转野生荠菜凝集素(WSA)基因棉花(Gossypium hirsutum)叶片,并以其亲本棉花叶片为对照,以牛粪为阴性对照,以农药为阳性对照,研究种植转WSA基因棉花对赤子爱胜蚓死亡率、生长及繁殖的影响。结果表明,在49 d的试验周期内,与取食亲本棉花叶片的赤子爱胜蚓相比,取食转WSA基因棉花叶片的赤子爱胜蚓的死亡率,体质量,GST、SOD、纤维素酶活性以及蚓茧数和小蚯蚓数均无显著差异,未发现转WSA基因棉花对赤子爱胜蚓有不利影响。     

环境雌激素o,p′-DDT和抗雌激素氟维司群对斑马鱼胚胎的复合效应

为探究雌激素与抗雌激素的复合效应,将斑马鱼(Danio rerio)的胚胎暴露于o,p′-DDT和氟维司群2种典型的环境内分泌干扰物中,考察胚胎孵化率、孵化时间和总畸形率,并用实时荧光定量PCR技术检测Vtg1、Vtg2和ERα等雌激素效应相关基因的mRNA转录水平.结果显示,与单一化合物的暴露相比,o,p′-DDT和...     

Ergonomic Diagnosis of the Driver’s Workplace in an Electric Locomotive

This paper deals with research aimed at developing a method for ergonomic analysis of the driver’s workplace in an electric locomotive. It presents the structure of the diagnosis and its assumptions, and includes a re-evaluation of the questionnaire-expert method in ergonomic research. The article presents research data on weights and evaluations including their standard deviations for particular priority features. Ergonomic levels of the studied operator’s cabin in locomotives are compared.     

An Observation Method for Analyzing Operators’ Routine Activity in Computerized Control Rooms

An activity analysis method was developed for studying the structure and dynamics of control room operators’ activity during normal operation based on directly observable elements of the operators’ behavior. The method assesses current activity along three dimensions in each 5-min period of the shift. Intensity characterizes arousal level, direction shows whether the activity is directed predominantly at the process control task, at something else, or miscellaneous. Motivation reflects if the activity is driven by intrinsic or extrinsic motivation. A case study is presented, in which 3 morning, 3 afternoon, and 3 night shifts of a Nuclear Power Plant operator crew are involved. The obtained results gave a deeper understanding of the operators’ activity and also revealed an “arousal compensation” tendency.     

Relationship of safety climate perceptions and job satisfaction among employees in the construction industry: the moderating role of age

This study examines the degree to which construction sector employees perceive that safety is important in their organizations/sites and how job satisfaction affects these perceptions when age is introduced as a moderator variable. Two-way analysis of variance demonstrated that job satisfaction has a strong effect on perceived management commitment to work safety and that this relationship was moderated by respondents’ age. Job satisfaction was associated with perceived accident rate and safety inspection frequency, but the proposed role of age in this linkage was not confirmed. Consequently, the findings indicated that by increasing the level of job satisfaction, perceptions of these safety climate aspects proved to be more positive. The conclusion is that these relationships could further lead to a lower percentage of accidents and injuries in the workplace and better health among employees. A significant relationship between job satisfaction, age and perceived co-workers’ commitment to work safety was not found.     

Prenatal diagnosis of twin zygosity by DNA ‘fingerprint’ analysis

A twin pregnancy with one hydrocephalic fetus with oligohydramnios is presented. Sonographic evaluation could not exclude monochorionicity. Before considering selective feticide, blood samples from both fetuses were examined for DNA ‘fingerprint’ analysis. The different banding patterns of the blood samples established dizygosity. This procedure is suggested in cases where sonography fails to determine chorionicity.     

环境污染对农民健康的影响研究

旨在分析农村环境污染的现状并究其根源,探讨生态环境问题给农民健康带来的危害,为治理农村环境污染提出合理对策。