Cu-ZnO/Al2O3催化仲丁醇制备甲乙酮     

林武滔  李增富  邱凡 《三明学院学报》2007,24(4):420-424

用Cu-ZnO/Al2O3催化仲丁醇制备甲乙酮。研究了催化剂的焙烧温度和焙烧时间、仲丁醇脱氢反应的温度和压力以及仲丁醇的流量对仲丁醇转化率和甲乙酮选择性的影响。结果表明,催化剂的焙烧温度为300-400℃,焙烧时间为6h,脱氢反应的温度为300℃,压力为0.2Mpa,仲丁醇的流量为140mL/h时,仲丁醇的转化率和甲乙酮的选择性较好。  相似文献   

Hydrogenation properties of mechanically milled Mg2Nio.8Cr0.2-CoO/Al2O3 composites     

WANG Xiu-li  TU Jiang-ping  CHEN Chang-pin  ZHANG Xiao-bin  ZHAO Xin-bing 《Journal of Zhejiang University. Science. B》2005,(3)

Mg2Ni0.8Cr0.2-x wt.% CoO/Al2O3 (x=0.5, 1, 2 and 3) composites were prepared by mechanically milling sintered Mg2Ni0.8Cr0.2 alloy and CoO/Al2O3 compound for 45 h. The addition of CoO/Al2O3 compound resulted in the good kinetics properties of hydriding/dehydriding reaction of the composites. The composite with 1.0 wt.% CoO/Al2O3 catalyst could reach the maximum hydrogen absorption capacity (2.9 wt.%) within 5 min at 393 K under H2 pressure of 4 MPa, and can desorb rapidly at 493 K. The decomposition and synthesis of hydrogen molecule on Mg2Ni0.8Cr0.2 alloy surface was promoted by addition of CoO/Al2O3 catalyst. In addition, the formation of metallic Ni particles, strain and defects during the ball milling process also resulted in the improved hydrogenation performance of Mg2Ni-based alloys.  相似文献   

结合专业特色应用现代教育技术服务于中小学教学     

苟泽志 《保山师专学报》2005,24(3):103-104

现代教育技术的应用,深刻影响高中小学各科教学.传统的教学模式必须与现代教育技术进行整合,才能适应新课程教学改革的需要.充分发挥教育技术专业人才的主导作用,担当教育技术现代化的排头兵.  相似文献   

从认知心理学的研究看幼儿的自我中心言语     

王晓芬 《幼儿教育》2007,(18)

幼儿的自我中心言语是一种正常的心理现象,是幼儿心理发展和语言学习的必经之路。认知心理学关于前额叶发展、执行功能发展和幼儿思维发展特点的研究能有效地解释幼儿自我中心言语产生的原因。皮亚杰、维果茨基等理论家对幼儿自我中心言语的研究则给幼儿教育工作者提供了借鉴与启示。  相似文献   

Growing up in a tourist destination: developing an environmental sensitivity     

Antonia Canosa  Anne Graham  Erica Wilson 《Environmental Education Research》2020,26(7):1027-1042

Abstract

This paper explores how the socio-cultural milieu of a community may foster a sense of environmental stewardship among children and young people. Ethnographic fieldwork, carried out in a popular tourist destination in Australia, revealed that the overt impacts of tourism activity such as littering provoke negative feelings among children and young people; these perceptions can in turn translate into a sensitivity towards the environment. While debated in some circles, a Significant Life Experiences (SLE) lens is useful in understanding children and young people’s lived experiences of – and sensitivity to - environmental issues in the communities where they are raised. SLE is employed in this article to explore how a sense of stewardship towards the environment is developed among children and young people growing up in a tourist destination. Findings suggest they actively contribute to protecting the environment in a variety of ways from regular beach clean ups and educating visiting tourists to participating in rallies and anti-development protests.  相似文献   

实时多媒体数据传输的研究及实现     

董芳  吴秀  费新元 《黔南民族师范学院学报》2003,23(3):1-4

本文主要进行RTP／RTCP与TCP协议的比较，着重分析RTP／RTCP协议对分组网上视频业务Qos的保证。在IP电话的实现中编码后的数据流采用RTP／RTCP协议来打包传送。结果表明，开发出的软件实时性好。  相似文献   

8253定时/计数器方式3计数过程的实验研究     

姜华  燕凤灵 《楚雄师范学院学报》2007,22(9):26-29

对于我系选用教材和部分参考资料关于8253定时/计数器在方式3的计数过程中表述中所存在的矛盾之处,基于武汉众友电子科技有限公司的接口实验台,提出了一个探究8253计数过程的实验方案。通过分析实验结果,指出了正确的计数过程。  相似文献   

Three dimensional couette flow and heat transfer through a porous medium with variable permeability     

Chaudhary?R.?C.?Email author  Sharma?Pawan?Kumar 《浙江大学学报(A卷英文版)》2003,4(2):181-185

This paper reports research on the effects of variations in injection velocity and permeability on the heat transfer and flow through a highly porous medium between two horizontal parallel plates situated at constant distance with constant suction by the upper plate. Due to this type of variation in injection velocity and in permeability the flow becomes three dimensional. The governing equations are solved by adopting complex variable notations to obtain the expressions for the velocity and temperature field. The skin-friction along the main flow direction and rate of heat transfer are discussed with the help of graphs.  相似文献   

Consolidation behavior of cement- and lime/cement-mixed column foundations   总被引：1，自引：1，他引：1  

蔡袁强  徐长节 《浙江大学学报(A卷英文版)》2002,3(5):507-512

The consolidation behavior of mixed in place cement- and lime/cement-mixed column was studied. Consolidation of the composite foundation was modeled as a three-dimensional axi-symmetric problem. The authors used the finite difference method to obtain the pore pressure variation with time at any location below the surface. A computer program developed by the authors was used to draw some interesting conclusions about the consolidation behaviors of cement- and lime/cement-mixed pile foundation. Finally, a combined model including the permeability coefficients of cement-mixed piles and soil, was studied and its feasibility was evaluated. Project supported by National Natural Science Foundation of China (No. 59908012) and Education Ministry of China  相似文献   

CeO2载体对Au/CeO2催化剂CO氧化活性的影响     

单文娟  刘畅 《华章》2011,(3)

采用六水硝酸铈和氢氧化钠为反应物,用水熟合成法制备了纳米Ce02.并以不同合成条件下得到的CeO2为栽体,担载了相同含量的贵金属Au,制备了具有高活性的Au/CeO2催化荆.实验结果发现,以CeO1-2h为载体的催化剂在高温区易展现出较好的活性,而以CeO2-10h为载体的催化剂在低温区易展现出较好的活性.说明载体结构对催化荆的CO催化氧化活性有决定性的作用.  相似文献