Study on the Catalysts for Selective Oxidation of Propylene to Acrolein

丙烯醛是一种重要的有机化工中间体，目前市场上最大的应用是用于合成丙烯酸和蛋氨酸。本论文采用分步共沉淀法制备了一系列钼铋系复合金属催化剂，该催化剂合成的丙烯醛选择性高、副产物丙烯酸少，是一种适合生产蛋氨酸的丙烯醛催化剂。催化剂的配方由下列通式表示：Mo12Bi1FeaCobMncKdSieOx。论文优化了催化剂的制备方法，在制备过程中添加柠檬酸和乙二醇等有机物燃烧剂，通过一步燃烧法，获得所需催化剂。燃烧剂在干燥和焙烧过程中，有效地调节了催化剂比表面积和孔容等物性参数，提高催化剂的分散性，从而改善了催化剂的选择性。论文主要包括以下几个方面的工作： 1.采用分步共沉淀法制备催化剂。在Mo12Bi1...Acrolein is an important organic intermediate. The most extensive application on market is to synthesize acrylic acid and methionine. Stepwise co-precipitation method is used to prepare Mo-Bi-based catalysts. The acrolein selectivity measured over the catalysts is higher and the yield of byproduct acrylic acid is lower. So as-produced product, acrolein, can properly used for the synthesis of methi...学位：理学硕士院系专业：化学化工学院_物理化学(含化学物理)学号：2052011115155

A Statistical Observation of Crowns and Bridges in 1992 Part 1 Single crowns

A study was made of 1006 crowns which had been fabricated for patients at the Prosthodontic Clinic of Matsumoto Dental College during 1992. Some of results were as follows. 1) 42.8% of the patients were males and 57.2% were females. 2) 90.0% of the patients were between 20 and 69 years old. 3) Crowns of the upper abutment teeth were more numerous than those of lower abutment teeth. 4) 75.0% of the crowns were fabricated for nonvital teeth. 5) 49.2% of the crowns were fabricated as full cast crowns, 27.6% as facing crowns (6.3% as porcelain fused to metal crowns, 21.4% as res-in facing crowns), 3.6% as jacket crowns (3.6% as resin jacket crowns and no porcelain jacket crowns was fabricated), and 19.1% as partial coverage crowns, and no dowel crowns was fabricated

碱处理法改性ZSM-5分子筛催化苯与乙醇烷基化制乙苯

用不同浓度的NaOH溶液对ZSM-5分子筛进行改性,以XRD、SEM、NH3-TPD和BET方法对改性前后的催化剂进行表征,并考察了碱处理改性对ZSM-5分子筛孔结构、酸性以及催化苯与乙醇烷基化反应的性能的影响.结果表明,通过调变NaOH溶液浓度可以在保持ZSM-5分子筛的微孔骨架结构的同时,调变介孔分布.随着NaOH溶液浓度升高,ZSM-5分子筛的酸量、介孔孔容、介孔表面积都增加,孔径分布变宽,从而改善了催化剂的催化性能.对ZSM-5分子筛进行碱改性,比较合适的NaOH溶液浓度为0.2mol/L,改性后的ZSM-5分子筛催化剂具有较高的活性和稳定性.但超过0.5mol/L的NaOH溶液会破坏ZSM-5分子筛骨架结构,该浓度的NaOH溶液改性后的ZSM-5分子筛催化活性下降较快

Promotion of Magnesium Oxide on Catalyst for Ethylbenzene Dehydrogenation to Styrene

制备了一系列不同Mg含量的fE-k-CE-Mg乙苯脱氢催化剂,并以Xrd、CO2-TPd、nH3-TPd和bET等方法对催化剂进行表征,考察MgO对乙苯脱氢催化剂表面结构、酸碱性以及催化性能的影响.结果表明,添加适量的MgO可以增大催化剂的孔径和孔容,降低比表面积,形成的MgfE2O4新相有助于分散催化剂表面的活性相kfEO2和kfE11O17,并增加催化剂表面CEO2的含量,同时也调节催化剂表面的酸碱度,降低催化剂表观活化能,在水油体积比1.3且空速为1H-1时,MgO的质量分数为6%的催化剂活性最高.A series of Fe-K-Ce-Mg based catalysts for ethylbenzene(EB) dehydrogenation to styrene were prepared and characterized by means of X-ray diffraction(XRD),temperature-program desorption(CO2-TPD,NH3-TPD),BET techniques.The effect of the content of magnesium oxide added on the performance of the catalysts for the reaction was investigated.The catalyst activity of the MG-6 catalyst containing 6% magnesium oxide was found to be best for the reaction under the conditions of water-oil volume ratio about 1.3 and space velocity 1 h-1.The characterization results showed that the pore size and pore volume of the catalyst increased as increasing the content of magnesium oxide,while,the surface area decreased by adding magnesium oxide;new phase MgFe2O4 promoted the formation of KFeO2 and KFe11O17 and increased the content of CeO2 on the catalyst surface,adding magnesium oxide also adjusted the acidity-alkalinity of catalyst surface and decreased the apparent activation energy values,which was found to be responsible for the improvement of the catalyst

策勒河流域地貌形态及其对生态格局的影响/Landforms and Their Effects on Ecological Pattern in the Qira River Basin[J]

策勒河发源于昆仑山中段北坡,自南向北流入塔里木盆地,流域为干旱区典型的山地-绿洲-荒漠格局.利用GIS软件对策勒河流域的数字高程模型数据进行处理,并结合其他资料进行综合分析.结果表明:1 500～3 500m的中海拔地区地貌形态类型多样,面积占总流域面积的58.05%;地形坡度≤15°的平缓、微缓、缓坡地区占70.31%;流域内东北和东两个坡向的面积占优势,分别占流域总面积的15.40%和14.19%;流域切割深度最小值为0 m,最大值281 m,大于20 m的区域占流域面积的28.68%;流域内切割密度最小值为0,最大为7.81 km/km2,大于1 km/km2的区域占流域面积的42.74%.该流域生态格局的特点表现在山地从高到低植被的分带变化上,利用ArcGIS平台对植被类型图进行归类处理,并与高程数据叠加分析得到策勒河流域生态格局的垂直带谱.研究结果丰富了地貌及生态地貌学研究的内容,为流域环境保护、生态恢复与水土保持提供参考