混合稀土的添加对PtSnNa/ZSM-5催化剂丙烷脱氢性能的影响

The influence of mischmetal addition on physicochemical properties of PtSnNa/ZSM-5 catalyst was studied by means of XRF,H 2 chemisorption,XRD,TPR,NH 3-TPD and TPO techniques.The results showed that the presence of mischmetal had an obvious impact on the catalytic performance of the PtSnNa/ZSM-5 catalyst.A suitable content of mischmetal not only could enhance the interactions between Pt species and the support,but also inhibit the formation of coke during the reaction,thus improving the catalytic activity and stability.In our experiments,when the content of mischmetal was 3m%,the catalyst exhibited best catalytic performance.However,the continuous addition of mischmetal could promote the reduction of Sn species to metallic tin,which was disadvantageous to the reaction.     

企业环境竞争力评价指标体系的构建

本文以研究并建立企业环境竞争力评价指标体系为目标，对企业环境竞争力评价指标体系进行初步构建，为后期建立综合评价指标体系奠定基础，使之应用于指导企业环境竞争力的评价工作。     

奥地利、西班牙、意大利、巴西的电网改革

分析考察国在电力市场结构下电网运行、规划、管理,水电开发与经济运行,电网改革的模式,组织机构设置、人员构成、电力市场安全运行管理、经济与财务管理、产权关系等情况,许多国家均结合本国国情在发、输、配、售4个环节和监督管理、产权管理、运行管理和市场管理等方面进行了有益探索;认为实现厂网分开,成立在国家监管下的垄断经营的电网公司是电力改革的发展方向。     

固相研磨法合成MgO-Al2O3/ZSM-5及其丙烷脱氢催化反应性能的研究

Solid-state grinding is a simple and effective method to introduce guest species into the channels of microporous materials through filling.The structure and the surface acidity of the materials were obtained from BET isotherms and NH3-TPD, respectively.XRD, UV-vis, UV diffuse-reflectance, and TEM were used to characterize the phases, and the morphology, respectively.The clustered layers of MgO-Al2O3phases were formed in the internal pore surface and were highly dispersed inside the channels of the ZSM-5 host.So the volume of MgO-Al2O3/ZSM-5 composite was larger than the ZSM-5 zeolite itself and some mesoporous channels appeared when Mg/Al species entered the channels.Meanwhile, new acid sites emerged in MgO-Al2O3/ZSM-5 composite and the acid amount of the sample changed.The improved Pt dispersion and the increased acid content would cause the increase of propane conversion and the modification of selectivity during the reaction.     

浸渍顺序对PtSnNa/ZSM-5催化剂丙烷脱氢性能的影响

The effects of the sequence for impregnation of metal precursors on the performance of PtSnNa/ZSM-5 catalyst for propane dehydrogenation to propene were studied in this paper. Some methods such as XRD, TPDA, BET, H2-TPR, XPS, ICP, TEM and hydrogen chemisorption were used to characterize the catalysts. The structure of ZSM-5 zeolite was not destroyed by the introduction of metal components. Meanwhile the different impregnation sequence of metal precursors could affect the behavior of Sn4＋ species entering the ZSM-5 channel, and the interaction between platinum and tin species, as well as the degree for reduction of Pt and Sn components. As a result, the prepared catalysts exhibited different reac- tion activity and selectivity. Compared with the co-impregnation treated catalyst, the catalysts prepared by the sequential impregnation method showed better catalytic activity in propane dehydrogenation, especially the one prepared through impregnation with tin precursor at first. Finally, a model for the effect of impregnation sequence on the distribution of Pt and Sn species in PtSnNa/ZSM-5 catalyst was proposed.     

纤维素分解菌的筛选及其紫外诱变

利用羧甲基纤维素钠为唯一碳源培养基从朽木、腐烂的竹叶与稻草中分离得到8株纤维素分解菌,测定了其产酶活性。对其中产酶活性较高的2#菌株进行紫外线诱变,进一步筛选得到突变株M10,其相对酶活较出发菌株提高了89.1%。     

乙炔和三氯硅烷的加成反应探讨

考察了3种不同特点的物料进样方式对乙炔和三氯硅烷的硅氢加成反应的影响；研究了温度，溶剂及乙炔流量等反应条件，对第三种进样方式的硅氢加成反应的作用规律，确定了具有高硅烷转化率和一次加成选择性的进样方式以及合适的反应条件。通过直接水解的方法合成了聚甲基乙烯基硅氧烷。首次以此作为保护剂，加热二甲苯溶剂下的氯铂酸，得到了稳定的金属铂胶体。结果表明，此保护剂存在下的铂胶体对乙炔和三氯硅烷的硅氢加成反应有良好的反应活性和稳定性。     

ＳＴＥＡＭ教育下的深度学习评价指标体系

本文是利用微波等离子体化学气相沉积的方法,在钛金属层上快速制备出由众多内部中空、外观呈锥形链状的碳纳米管组成的碳膜。通过扫描电镜、透射电镜、拉曼光谱等仪器分析了碳纳米管的组成。在真空条件下,测量了碳纳米管链薄膜的场电子发射特性。用热动力学过程解释了锥形碳纳米链的生长机理。