非水溶剂溶胶-凝胶法制备的纳米卤氧化镧在甲烷氧化偶联反应中的应用

采用非水溶剂溶胶-凝胶法制备了具有四方晶体相结构的纳米LaOX(X=Cl,Br).X射线粉末衍射和扫描电子显微镜结果表明,纳米LaOX样品的形貌规整、粒径均匀(平均粒径约为47nm).在甲烷氧化偶联(OCM)反应中,纳米LaOX显示出比常规尺度LaOX更高的催化活性和C2选择性,且纳米LaOX具有良好的稳定性.此外,常规尺度下,LaOBr催化剂活性和C2选择性高于LaOCl;纳米尺度下,两催化剂活性相差不大,但LaOBr上C2选择性明显更高

Ni的化学态对甲烷部分氧化反应机理的影响:能学分析

采用键指数归一-平方势(UBI-QEP)法对不同化学态Ni上甲烷部分氧化反应中各可能基元步骤进行了能学计算研究.结果表明,反应的速度控制步骤与金属Ni的化学态有关.还原态Ni上CO形成的反应速度控制步骤为表面上CH_3与O物种间的缔合,而带部分正电荷的Ni上CO形成的反应速度控制步骤则为甲烷氧助解离形成表面CH_xO物种.还原态和带部分正电荷的Ni中心在表面上共存时,反应的速度控制步骤将取决于表面CH_3形成与表面CH_3、O物种缔合两反应间的竞争,其竞争的强弱涉及Ni的化学态.此外,反应活性中心向正电荷的Ni转化时,会导致表面C和O及H和H物种缔合的活化能显著降低,有利于CO、H_2的形成,而表面CH_x物种解离则变得不容易,表面积炭受到明显的抑制

Nano-lanthanum Oxyhalide Prepared by Nonaqueous Sol-Gel for Oxidative Coupling of Methane

LaOX (X = Cl, Br) nanoparticles with tetragonal crystal structure were successfully prepared via sol-gel approach with non-aqueous solvents. Characterizations by X-ray powder diffraction and scanning electronic microscopy show that the LaOX nanoparticles are regularly in shape and highly uniform in size with an average diameter of about 47 nm. For oxidative coupling of methane (OCM), the nanosize LaOX catalysts have higher methane conversion and C(2) selectivity than the LaOX catalysts with conventional size and show good stability in activity and selectivity during the catalyst life test at 650 degrees C. At conventional size, the methane conversion and C(2) selectivity for OCM over the LaOBr catalyst are higher than that over the LaOCl catalyst, and at nanosize, there is not so much difference in methane conversion between LaOBr and LaOCl. However, the C(2) selectivity for OCM reaction over LaoBr is significantly higher than that over LaOCl, especially at low temperature.National Basic Research Program of China (973 Program)[2010CB732303]; National Natural Science Foundation of China[21033006, 20923004, 20373054

集美大学2002级福建籍新生肝炎感染现状

目的　了解集美大学 2 0 0 2级福建籍新生甲、乙、戊 3型肝炎感染情况。方法　采用血清流行病学调查方法。结果　学生中抗HAV -IgG ,HBsAg和抗HEV -IgG阳性率分别为 77.0 8% ,1 5 .2 3 % ,1 7.1 5 % ,地区差异明显 ;HAV ,HEV无性别差异 ,而HBV以男性为高 ;农村HAV和HBV感染率均高于城镇 ,而HEV感染率无城乡差别。结论　应该加强对本地区大学生的甲、乙肝预防 ,急需研究出一种有效的戊肝疫

Influence of Ni Chemical States on the Partial Oxidation Mechanism of Methane: An Energetics Analysis

An energetics analysis of the possible elementary steps involved in the partial oxidation of methane (POM) over different chemical states of Ni was carried out using the unity bond index-quadratic exponential potential (UBI-QEP) method. The results show that the rate determining step for the partial oxidation mechanism of methane is related to the chemical state of the Ni. Over reduced Ni the rate determining step for CO formation is the association of surface CH(3) species with surface O species. Over a partial positive charged Ni surface the rate determining step is that methane dissociates into the CH(x)O species with the assistance of oxygen. Over the reduced and partial positive charged Ni sites in coexistence, however, the rate determining step depends on the competition between the formation of surface CH(3) species and the recombination of surface CH(3) species with surface O species. This competition is related to the chemical states of the Ni sites. If the partial positive charged Ni sites are predominant on the surface, the recombination of surface C species with surface O species and the recombination of surface H atom species favor CO and H(2) formation because of decreasing barriers. The surface CH(x) species does not dissociate easily and surface carbon deposition is significantly inhibited.National Natural Science Foundation of China[21033006, 20923004]; Natural Science Foundation of Fujian Province, China[2007J0168]; National Key Basic Research Program of China (973)[2010CB732303

Prevalence of hepatitis B virus infection and phylogenetic analysis of HBV S gene among high school students

目的了解江苏省海门市高中生乙型肝炎感染情况及其HbV S基因的变异情况。方法采用整群抽样方法抽取江苏省海门市职业中心校的407名高三学生进行乙肝血清学调查;采用酶联免疫吸附法(ElISA)和巢氏聚合酶链式反应(PCr)扩增方法检测血清样本的乙型肝炎表面抗原(HbSAg)、乙型肝炎病毒表面抗体(抗-HbS)和乙型肝炎病毒(HbV)S基因并进行进化分析。结果 407名高中生中乙肝表面抗原(HbSAg)阳性率为6.39%;在家中、乡镇卫生院和县级及以上医院出生学生的HbSAg阳性率分别为11.76%、8.02%和2.27%,差异有统计学意义(P<0.05);抗-HbS滴度≥10u/l者占72.5%,且呈u形分布;不同乡镇、不同性别学生抗-HbS滴度差异有统计学意义(P<0.01);407名高中生HbV S基因均为C基因型,主要变异在蛋白疏水区,抗原决定簇A区未发生免疫原性改变。结论出生时接受的医疗水平对HbV感染有影响;海门市高中生HbV S基因受到正选择作用而出现变异,但未发生免疫原性改变。Objective To understand the hepatitis B infection and HBV S gene variation among high school students in Haimen city,Jiangsu province.Methods A serological survey of hepatitis B was conducted in a high school with cluster sampling method.HBsAg and anti-HBs were detected with ELISA,and phylogenetic analysis for HBV S gene with nested PCR.Results HBsAg positive rate was 6.39% and the rate for the students born at home,township health centers,and hospital above the county level was 11.76%,8.02%,and 2.27%,respectively,with significant difference(P<0.05).The percentage of the students with anti-HBs titer ≥ 10U/l was 72.5%,and the titer distribution was U-shaped.The difference in anti-HBs titer between boys and girls,as well as different towns,was statistically significant(P<0.01).All genotype of HBV S gene was C-type,and the main variation was in protein hydrophobic area.The change of immunogenicity in antigenic determinant "a" zone was not observed.Conclusion The level of health care at birth can affect the HBV infection among high school students in Haimen.S gene variation occurs through positive selection,but not antigenicity.国家科技支撑计划(2006BAI02A03);传染病重大专项(2008ZX10002-012);上海市重点学科项目(B118

Research on teaching method of waste pipe-network design in environmental engineering

随着社会经济的发展,城市排水管网系统的规模越来越大,逐步发展为一个复杂的大规模管网系统。如何设计和维护这样庞大的排水管网系统,不仅从根本上影响着管网系统的投资及维护管理费用,也会对城市环境保护和工业企业的发展有着深远的影响。文章在课程设计教学中对排水管网设计的两种方法,图表法和最优化法进行了比较和分析,介绍了如何用最优化法对教材中的实例进行设计。通过课程设计的实践表明,最优化法有助于学生掌握影响管网设计的关键水力要素的变化规律,加深对管网设计本质的理解。因此,有必要在给排水工程课程设计的教学中,引入最优化的理论和设计方法。 With the development of society economy,the scale of the waste pipe-network have become more and more large and the structure of the system is also more complex.How to design and maintain the large waste pipe-network will ultimately affect the system capital and maintained cost,as well as deeply affect the environment protect of the city and the development of the industry.In this paper,two methods in waste pipe-network design,i.e.the chart method and the optimization method,were analyzed and compared,and then how to design the example in textbook with the optimization method also was introduced.The practice of course design indicates that the optimization method is helpful for students to master the change rules of the key hydraulic factors and to deepen understanding the essence of pipe-network design.Therefore,it is necessary to introduce the theory and method of the optimization in the course design teaching of the water and waste engineering.广西民族大学校级教改课题资助项目(2011XJGB19);广西基础化学实验教学示范中心教学研究专项(Y21

Comprehensively Implement the Scientific Developing Concept,Academic and Practical Research on College Students Environmental Consciousness

从环境保护的涵义和构成以及人与自然的和谐发展出发,强调落实科学发展观,培养当代大学生的环境意识的重要意义。阐述作为高校环境工程专业教师如何在高校普通大学生、理工科化学化工生物类大学生、环境科学类大学生中渗透环境保护理念的实践和探索。广西民族学院高等教育教学改革工程项目(民院教发[2005]19号

Study on Training of Practice Ability for Environmental Engineering

环境工程专业作为一门工程性和应用性很强的学科,它要求本专业的学生应具有一定的实践操作能力,工程设计和管理能力。因此在环境工程专业教学中需加强对学生工程实践能力,创新能力的培养,以适应不断发展壮大的环保产业对高素质人才的需求。文章对环境工程专业实践教学体系的构建进行了研究和探讨,以便促进教学工作,提高教学质量。 The environmental engineering specialty is characterize by engineering and application,the undergraduate student should have the abilities in practical operation,in engineering design and management.Therefore constructing and enhancing the practical teaching system is necessary to meet the requirement of the growing environment protection industry.This paper conducted a study to constructing this system and applying it.广西民族大学校级教改课题资助项目(2011XJGB19);广西基础化学实验教学示范中心教学研究专项(Y21

一种圆环链喷砂机

一种圆环链喷砂机,主要由传动单元、激振单元、喷砂单元、回砂单元、密封单元以及喷砂房组成。工作时,圆环链通过左侧密封单元从入口进入喷砂房后,进入激振单元的振动斗内,通过控制振动斗两端的主动链轮使圆环链在振动斗内保持一定长度的预送段,激振单元对预送段施加振动使其姿态变换,相互脱开出现缝隙,同时设置在上方的喷枪对预送段实施喷砂,磨料即可顺利进入缝隙内部,杜绝漏喷现象,在满足作业要求后预送段离开振动斗并经出口处的密封单元运行出喷砂房,后续圆环链进入振动斗。本发明可在封闭环境中对过长圆环链进行连续喷砂处理,解决现有过长圆环链喷砂作业中存在效率低、易漏喷、要求场地面积大、劳动强度大以及污染严重的技术问题