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1.
研究了物理法制备的纳米过渡金属催化剂上CO的氧化反应及催化剂活性组分与其催化活性的关系。试验结果表明,纳米铜催化剂对CO2氧化反应有较好的催化活必 化剂活性组分金属氧化物生成热与其催CO化反应催化活性之间关联。  相似文献   

2.
以乙酸和丁醇的酯化为探针反应,着重考察了制备条件对SO2-4MoO3ZrO2超强酸催化剂催化活性的影响;考察了催化剂的使用寿命。结果表明,MoO3含量和焙烧温度对催化活性有显著影响,而H2SO4浓度对催化活性的影响却不明显;催化剂具有较好的稳定性及使用寿命。另外,用XRD、FTIR等分析方法对催化剂进行了物性测试。  相似文献   

3.
以电弧等出子体法制备纳米铜活性组分,物理法制备出负载型的米Cu/γ-Al2O3催化剂,用于催化CO氧化反应,发现催化活性在催化过程中呈规律性变化,即初始活性较低,空气中焙烧预处理易使纳米粒子长大,催化剂的氧与CO还原实验表明铜氧化物活性高于Cu^0。  相似文献   

4.
以浸渍沉淀负载法制备了SO2-4/TiO2/ZSM-5分子筛催化剂.用XRD,IR,DTA,TG,NH3-TPD,ICP等对催化剂的物化性能进行表征,考察了它对酯化反应制乙酸丁酯的催化活性.结果表明:催化剂含TiO2为6.0wt%,SO2-4为3.2wt%,在最佳条件下,乙酸的转化率达98.8%,选择性为100%,达到以硫酸为催化剂的催化活性.该催化剂具有制备简单,不腐蚀设备,无副反应,成本低,热稳定性好,活性衰退慢等优点,可望开发应用.  相似文献   

5.
SO^2—4/TiO2/ZSM—5催化剂催化性能的研究   总被引:4,自引:0,他引:4  
以浸渍沉淀负载法制备了SO^2-4/TiO2/ZSM-5分子筛催化剂,用XRD,IR,DTA,TG,NH3-TPD,ICP等对催化剂的物化性能进行表征,考察了它对酯化反应制乙酸丁酯的催化活性。结果表明;催化剂含TiO2为6.0wt%,SO^2-4为3.2wt%,在最佳条件下,乙酸的转化率达98.8%,选择性为100T〉达到以硫酸为催化剂的催化活性。  相似文献   

6.
应用于气相苯加氢反应的Pd/C催化剂的研究   总被引:3,自引:0,他引:3  
梁红 《江西科学》1996,14(3):148-155
研究了Pd/C催化剂的制备条件对Pd的分散度、晶粒大小及催化活性的影响。结果显示,离子交换法所用的交换液浓度、pH值、焙烧温度对表面性质及催化活性均有不同的影响。采用H2-O2滴定、扫描电镜(SEM)和俄歇电子能谱等手段进行了表征。并对Pd/C催化剂在气相苯加氢反应中“结构敏感”与否的问题进行了讨论。  相似文献   

7.
合成了不同种类的SO4^2-/MxOy型固体超强酸催化剂,并考察了各种催化剂对合成核黄素四丙酸酯反应活性的影响,发现SO4^2-/ZrO2固体超强酸催化剂活性最高,通过单因子实验,探讨了SO4^2-/ZrO2的制备条件、催化剂用量、反应温度和反应时间等因素对酯化反应的影响,优化了催化剂制备条件,实验结果表明:SO4^2-/ZrO2固体超强酸催化剂对核黄素四丙酸酯的合成反应具有良好的催化活性,具有易  相似文献   

8.
pH对制备CuO—ZnO—ZrO2低压合成甲醇催化剂的影响   总被引:1,自引:0,他引:1  
通过活性测定,XRD,TPR等手考察在制备CuO-ZnO-ZrO2低压合成甲醇催化剂时PH值对其活性,物相及还原特性的影响。结果表明:制备催化剂时PH对其催化活性的影响很大。  相似文献   

9.
稀土改性SO^2—4/TiO2固体超强酸催化民水杨酸异戊酯   总被引:9,自引:2,他引:7  
采用稀土改性SO^2-4/TiO2固体超强酸催化合成水杨酸异戊酯。结果表明,该种催化剂不但具有一般超强酸的性能,而且催化活性高,制备工艺简便,讨论了该种催化剂的制备条件以及反应条件对酯化反应的影响。  相似文献   

10.
采用浸渍法制备固体磷酸催化剂,以汽油氧化脱硫反应为催化模型,研究了焙烧温度、浸渍时间及载体对所制备的固体磷酸催化剂的催化活性的影响.结果表明,硅藻土磷酸催化剂在汽油脱硫反应中的催化活性与焙烧温度有关;活性炭磷酸催化剂在汽油氧化脱硫中具有较好的催化活性.在酸量为5.613 mmol/g时,催化剂的催化活性最高.  相似文献   

11.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

14.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

15.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

16.
17.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

18.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

19.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

20.
Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.  相似文献   

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