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1.
FCC油浆热转化制备中间相沥青的研究   总被引:1,自引:0,他引:1  
研究了催化裂化(FCC)油浆在热转化过程中生成高含量中间相沥青的规律。采用程序升温、多管井式坩埚炉进行热转化反应,通过族组成分析、光学显微镜、核磁共振、以及元素分析研究了FCC油浆热转化过程中中间相沥青的形成规律。实验结果表明:中间相沥青形成经历了3个阶段,即微晶形成、微晶生长及中间相小球融并,前2个阶段是缓慢过程,后1个阶段是快速过程。随着温度的升高,不溶物的浓度呈现出不断升高的趋势。  相似文献   

2.
以主要化学成分为Ca O和Si O2的钢渣为原料,制备Si O2-Ca O-Al2O3系钢渣陶瓷,采用差分扫描量热仪(DSC)、X线衍射仪(XRD)、扫描电子显微镜(SEM)与热力学计算研究钢渣陶瓷烧结过程及反应机理。研究结果表明:在以钢渣-黏土-长石-石英为主要原料的Si O2-Ca O-Al2O3体系中,钢渣陶瓷晶相以钙长石相为主;钢渣陶瓷烧结初期以扩散传质反应为主,之后形成高温液相,促进反应进行和晶体长大,并完成坯体致密化;经过湿磨的钢渣中存在大量的氢氧化钙等矿相,这些矿相在钢渣陶瓷烧结过程中能够分解产生具有很强反应活性的氧化钙,因而促进了原料间的反应和陶瓷致密化过程。  相似文献   

3.
本文对山西三种不同类型的煤沥青进行了溶剂配制,用示差精密热分析仪研完了它们的热行为;在热台显微镜下观察了它们在热反应过程中的软化熔融温度、中间相的生成和变化温区及显微结构的变化。结果表明:太钢煤沥青在生成中间相的过程中有良好的热行为,有可能成为制备碳纤维的良好原料。  相似文献   

4.
研究了SiC晶体高温化学气相沉积生长机理,从Sic晶体高温化学气相沉积生长过程的化学原理、反应条件、反应过程、一般工艺等方面进行探讨,并分析了沉积温度、气体压力、本底真空及各反应气体分压(配比)对SiC单晶生长及其缺陷形成的影响,基于以上分析,得出高温化学气相沉积法生长碳化硅晶体最佳的工艺条件.  相似文献   

5.
木质纤维素生物质细胞壁中主要组分(纤维素、半纤维素和木质素)相互交织形成的网状结构是生物质转化过程中的天然抗降解屏障。有效的预处理能打破这种屏障,提高酶水解转化效率。显微技术包括显微镜技术和显微光谱技术,能够在多尺度下展现木质纤维素生物质在预处理中细胞壁微观结构变化和组分含量等信息。笔者介绍了原子力显微镜、扫描电子显微镜、透射电子显微镜、显微拉曼光谱等显微技术在木质纤维素生物质预处理过程研究中的应用。利用显微镜技术可直接观察预处理中细胞壁表面结构的变化,并分析其对酶水解可能产生的影响; 利用显微光谱技术可原位分析预处理对细胞壁组分化学结构与超微结构的影响; 多种显微技术组合弥补了单一手段的不足,可获得木质纤维原料生物构造、组分含量及分布等方面更为详细的信息。  相似文献   

6.
常压盐溶液法转化脱硫石膏制备α-半水石膏的相变机理   总被引:2,自引:0,他引:2  
采用常压复合盐溶液水热法对钙基湿法烟气脱硫(FGD)工艺的副产品FGD石膏进行转化,以制备α-半水石膏。利用DSC/TG综合热分析、SEM和化学分析对转化后的石膏样品进行研究。结果表明,FGD石膏转化为α-半水石膏的过程遵循溶解-重结晶机理。在重结晶诱导期内,FGD石膏首先在热盐溶液中溶解,形成硫酸钙过饱和溶液,在一定的过饱和度区域内,α-半水石膏雏晶直接从溶液中析出,发生石膏晶体亚微观结构上的改变。随后石膏雏晶继续生长,形成了均匀粗大的棱柱状α-半水石膏晶体,实现结晶物质在各个晶体上的重新分布。  相似文献   

7.
锂盐电解质对中间相石墨微球电化学性能的影响   总被引:1,自引:0,他引:1  
中间相就是稠环芳烃化合物在液相炭化过程中所形成的一种向列液晶结构 ,在中间相转化的初期由于表面张力的作用而呈球形 ,将其用适当的方法从母液中分离出来即是中间相炭微球 (MesocarbonMicrobeads简称MCMB) .本文将含有一定量原生喹啉不溶物的煤沥青基中间相炭微球 ,在 2 80 0℃条件下进行高温石墨化 ,表征了试样的微观结构 ,考察电解液组成对其用作锂离子电池负极材料时电化学性能的影响 .1 实验部分以精制煤焦油沥青为原料 ,在一定的工艺条件下制得含有部分原生喹啉不溶物的煤沥青中间相炭微球 ,将其放入中频…  相似文献   

8.
利用同步辐射宽角X射线衍射原位研究了淬冷得到的中间相和由其被拉伸得到的取向中间相在升温和等温退火下向晶体的转变过程.实验结果表明,虽然两者开始相转变形成晶体的温度是相同的,但发生大量相转变所需的温度,取向的中间相要明显高于淬冷直接得到的中间相,这说明前者具有更高的稳定性.通过对比两种不同中间相的初始结构,发现取向后的中间相在沿拉伸方向31螺旋结构具有更大的长程有序,从而导致了其具有更高的熔点.  相似文献   

9.
用大型金相显微镜观察了高温溶液生长的五磷酸镧钕(NdLaPP)晶体的表面特征。这些特征是:晶面花纹、生长丘、邻位面和铁弹畴。实验表明:晶面花纹是晶体内部缺陷在生长面上的反映。因此,观察晶面花纹就可直接地判断晶体内部质量,这在大晶体上选取较完整部分制作激光棒或作晶种是一种方便,有效的方法。根据生长面上出现的生长丘、邻位面等表面特征,可以确定在该晶体生长过程中螺位错生长机制起主要作用。  相似文献   

10.
利用红外光谱分析和差热分析探讨了神木镜煤和柳林镜煤的碳化过程与组成结构的关系.柳林镜煤在碳化过程中经历中间相的生成发展阶段形成各向异性半焦,而神木镜煤则直接形成各相同性年焦.结构分析表明神木镜煤羟基官能团含量高,碳化初期易发生缩合反应,从而制约了中间相的形成和发展.  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
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   

14.
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。  相似文献   

15.
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.  相似文献   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
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.  相似文献   

18.
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.  相似文献   

19.
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-  相似文献   

20.
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-  相似文献   

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