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1.
首次制备了S_2O_8~(2-)/ZrO_2固体超强酸,确证室温下它对正丁烷的反应活性比S_2O_4~(2-)/ZrO_2固体超强酸更强,对ZrO2有促进作用的非卤素阴离子中,S_2O_8~(2-)是最有效的.它的最佳焙烧温度是600℃,比S_2O_4~(2-)/ZrO_2体系低50℃,且于35℃时,正了烷在S_2O_8~(2-)/ZrO_2体系上反应20h的转化率为50.4%,而相同条件下的S_2O_4~(2-)/ZrO_2体系上仅为36.7%。由于S_2O_8~(2-)/ZrO_2(600℃)的△σS=o=52cm-1,S_2O_8~(2-)/ZrO_2固体超强酸对正丁烷的强活性是因为它有比S_2O_4~(2-)/ZrO_2固体起强酸更强的酸性.  相似文献   

2.
以一氧化硫和正丙基硫醇为原料,用石油醚作溶剂,在-9℃下反应,合成了二正丙基四硫,产率由文献报道的46.6%提高到97.2%;通过气相色谱、红外光谱和色谱-质谱联用等分析手段证实了其结构.  相似文献   

3.
研究了沸点相近物质的萃取蒸馏分离方法,首次报道了邻、对氯甲苯的萃取蒸馏试验.在第三组份(溶剂)存在的情况下,环己烷和苯以及邻、对氯甲苯的相对挥发度都有了不同程度的改善,这对于它们的精馏分离具有一定意义.一缩二乙二醇对邻氯甲苯和对氯甲苯相对挥发度影响的机理还需进一步探讨.  相似文献   

4.
研究了以乙二醇为溶剂间歇萃取精馏乙醇-水共沸混合物的溶剂流率选择及回收过程.实验得出,乙醇-水体系的相对挥发度随溶剂比的增加而显著增大,水-乙二醇过渡馏分段持续时间很短.在该段时间会出现塔顶温度急剧跃升的现象;当回流比为2:1时,溶剂回收的收率可达到99.33%。  相似文献   

5.
测定了不同复盖度下的苯-正己烷和正庚烷-正己烷两个二组分气体在氧化铝上的组成吸附等温度,以及单组分气体在氧化铝上吸附的BET常数.结果表明,随着复盖度的增加,两个体系的组成吸附等温线都向下靠近它们各自的气液平衡曲线,可以近似地将二组分气相与吸附相的平衡看成二组分的气液两相平衡,两个体系的组成吸附等温线基本上都可以通过理想溶液的相对挥发度方程式模拟得到  相似文献   

6.
考察了离子液体1-乙基-3-甲基咪唑双三氟甲磺酰亚胺盐([EMIM][NTf2])对甲醇-甲乙酮共沸物系等压汽液相平衡的影响。首先测得了101.3 kPa下甲醇-甲乙酮-[EMIM][NTf2]三元体系的等压汽液相平衡数据,然后用非随机双液(NRTL)模型进行了关联,平均相对偏差为1.39%,表明了NRTL模型对含离子液体三元体系的良好适用性。经NRTL模型计算,在[EMIM][NTf2]的摩尔分数为0.047时可消除甲醇-甲乙酮共沸点。实验结果表明:[EMIM][NTf2]的加入对甲醇-甲乙酮体系表现出极强的盐效应,改变了体系的汽液相平衡,提高了甲醇对甲乙酮相对挥发度。因此[EMIM][NTf2]可作为甲醇-甲乙酮萃取精馏的萃取剂。  相似文献   

7.
文章采用改进的Rose气液平衡釜,测定了几种常见的盐对异戊醇和旋光戊醇体系的相对挥发度的影响。结果表明,一般的盐对该体系的相对挥发度的影响不大,其中ZnCl2使2种溶剂的相对挥发度增值最大,达到1.286;并从理论上简单探讨了导致该体系盐效应的差异不大的原因。  相似文献   

8.
在固-液相转换催化条件下,以石油醚为溶剂,KOH-K2CO3为去质子剂,四丁基溴化铵为催化剂,用1-溴丁烷和已内酰胺合成了1-正丁基氮杂环庚-2-酮.确定了优化合成条件为:己内酰胺:1-溴丁烷:四丁基溴化铵=1.1:1:0.056(物质的量比),反应温度为75℃,反应时间为4.5h,收率达89.6%.  相似文献   

9.
研究了HZSM-23分子筛和γ-Al2O3配比对HZSM-23/γ-Al2O3改性分子筛催化正丁烯异构化反应的转化率和选择性的影响.在中温及低空速条件下,随着配比中γ-Al2O3的增加,转化率降低而选择性有所提高.XRD.TPD及FT-IR对催化剂进行表征的结果显示:经改性后的HZSM-23的总酸量和强酸位减少,而L酸的浓度增加,正丁烯异构化反应的选择性主要取决于L酸位浓度.  相似文献   

10.
4-苯基-4-(1,2,4-三唑-1-基)-3-丁烯-2-酮可由3-溴-4-氯-4-苯基-2-丁酮在碱性条件下与1,2,4-三唑反应以71.4%的产率制得。其反应机理由实验和质谱证明是一个先消除氯化氢的三步反应过程,制备出了其衍生物4-苯基-4-(1,2,4-三唑-1-基)-3-丁烯-2-醇和和4-苯基-4-(1,2,4-三唑-1-基)-2-甲氧基-3-丁烯。测试结果表明,这些化合物具有较好的杀菌活性。  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.
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   

13.
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   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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   

16.
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   

17.
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   

18.
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   

19.
20.
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   

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