超声沉淀法制备CuO—Fe2O3纳米粉体催化剂

采用超声沉淀法制备了标题纳米粉体催化剂,运用XRD、IR、TEM等技术研究了粉体的组成,相结构、颗粒粒径及催化分解H2O2活性．结果表明,将超声辐射引入氧化物催化剂的沉淀法制备过程,可显著提高催化剂性能．文中对其原因作了初步讨论．     

不同方式合成纳米TiO2载体在SCR脱硝催化剂制备中的应用

通过不同方式合成纳米TiO2,并以此为载体负载活性物质制得1%V2O5-10%WO3/TiO2的SCR脱硝催化剂.纳米TiO2制备方式包括溶胶凝胶法、TiCl4水解法、直接沉淀及均相沉淀法.试验结果表明,用这4种方法制备得到的TiO2均为锐钛型,以均相沉淀法合成的纳米TiO2为载体制得的催化剂具有较高的比表面积及脱硝性能,并表现出明显的活性温度窗口.进一步引入超声作用优化均相沉淀反应条件,结果表明,相比同类型传统方法,超声均相沉淀工艺能够明显提高纳米TiO2产品的比表面积与分散度,缩小二次颗粒尺寸,并使得所制备催化剂脱硝性能得到显著提高,且具有较好的抗水、抗硫特性.     

磁性纳米催化剂SO_4~(2-)/TiO_2-Fe_3O_4的制备及表征

用溶胶凝胶法、沉淀法将磁性材料与固体酸进行组装,制备了磁性纳米固体酸催化剂SO_4~(2-)/TiO_2-Fe_3O_4.该类催化剂能通过外加磁场进行分离、回收.扫描电镜、透射电镜观察及磁性能、比表面积测试结果表明,用溶胶凝胶法制备的催化剂比用沉淀法制备的催化剂具有更小的粒径、更高的磁强度和更优异的催化性能.X射线衍射、傅里叶红外光谱分析表明,影响催化剂磁性能和催化活性的主要因素是Ti与Fe的摩尔比、焙烧温度和浸渍液浓度.     

Au／NiO催化剂的制备及其对CO催化氧化性能研究

采用不同制备方法翩备了Au/NiO催化剂,以CO氧化反应作为表征反应.考察了催化剂制备方法对催化剂活性的影响,在不同处理条件下制备了NiO载体.采用沉积-沉淀法制备了相应Au/NEO催化剂,进一步考察了载体的制备条件对催化剂性能的影响,并对催化剂进行了XRD、BET和TPR表征.实验结果表明:催化剂的制备方法对催化剂的催化活性有显著影响.经沉积-沉淀法制备催化剂的活性最好,而浸渍法制备的催化剂活性最差;载体的制备条件对催化剂的活性也有一定影响.在载体制备过程中加入分散剂并不能提高催化剂的活性,而载体经微波处理后的催化剂表现出较高的活性.BET结果显示负载于未经焙烧载体上的催化剂活性较高可能和催化剂较高的比表面积有关;TPR结果显示催化剂含有氧化态的金,而且催化剂的活性与氧化态金的还原温度相关.     

超细氧化铈制备工艺研究

针对传统的沉淀法制备氧化铈工艺,研究了以Ce Cl3溶液为原料的超声喷雾热解法制备超细Ce O2短流程工艺路线.通过TG-DTA实验研究Ce Cl3·7H2O的热分解过程,利用XRD,SEM和TEM表征了沉淀法和喷雾热解法制得的样品,最后从产品、流程及资源综合利用等方面对两种工艺进行对比分析.结果表明:Ce Cl3·7H2O在25~233℃为脱水反应,热分解温度为500℃,高于583℃热分解完全;在600℃时超声喷雾热解法制备的Ce O2分散性好、形貌规则,粒度主要分布在0.11~0.80μm,沉淀法制备的Ce O2有团聚现象且形貌不规则.超声喷雾热解法是一种流程短、资源综合利用高且产品形貌规则的清洁工艺技术.     

沉积—沉淀法制备Ni/γ-Al2O3催化剂及TPR行为研究

以γ-Al2O3为载体,硝酸镍为活性组分前驱物,尿素为沉淀剂,通过沉积—沉淀法制备了高分散、高负载Ni/γ-Al2O3催化剂,并进行了H2-TPR表征。结果显示,使用沉积沉淀法制备的催化剂在620℃出现一弥散的耗氢峰,归属为高分散氧化镍的还原峰。通过添加表面活性剂得到了弱相互作用、高分散度的催化剂。     

TiO2纳米管负载金催化剂催化丙烯直接环氧化反应

采用沉积沉淀法制备了TiO2负载金催化剂,并用于催化丙烯直接环氧化反应.研究表明载体形态对金催化剂性能有明显影响,同粒状TiO2相比,以纳米管状TiO2为载体时,催化剂表面活性中心对反应产物环氧丙烷的吸附能力减弱,抑制了环氧丙烷的聚合副反应,从而显著延缓催化剂的失活.     

不同沉淀剂制备纳米氧化镍催化剂的比较研究

本文采用五种不同的沉淀剂,利用较简单的沉淀法制备了纳米NiO催化剂,并采用BET、SEM和XRD等手段对其进行了表征,结果表明,五种催化剂的比表面积大小顺序为K2CO3〉NH4HCO3〉CO（NH2）2〉NH3·H2O〉KOH,粒径大小顺序为K2CO3,NH4HCO3〉CO（NH2）2〉NH3·H2O,KOH。因此,沉淀法制备纳米NiO催化剂时,尿素为沉淀剂效果最佳。     

负载型Au/γ-Al2O3催化剂对丙酮的催化消除反应

采用沉积-沉淀法制备了负载型Au/γ-Al2O3催化剂,对丙酮蒸汽进行催化消除反应,探讨了催化剂中金含量、活化过程中不同活化温度、活化时间以及催化剂用量对催化活性的影响.并对催化剂进行了SEM和XRD表征,优化了制备条件.结果显示,控制活化处理温度为300 ℃、时间为1 h,以0.65 g、质量分数为2.5%的Au/γ-Al2O3催化剂能将浓度为4.66 g/m3丙酮在140 ℃下完全催化消除.图7,参14.     

负载型金催化剂的制备及其对CO催化氧化性能的研究

通过沉积沉淀法制备了负载型金催化剂,测定了其对CO的催化氧化性能.结果表明,催化剂的活性与催化剂的载体种类、焙烧温度和放置时间等因素有关;Au/TiO2和Au/CeO2催化剂的催化活性较高,而Au/ZnO催化剂的催化活性较低;焙烧温度影响催化剂的性能,焙烧温度为400℃时,催化剂活性最高;较长的放置时间会降低催化剂性能,这可能与活性组分粒径长大有关.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

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

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-