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1.
超临界CO2提取树兰花浸膏   总被引:6,自引:0,他引:6  
在33-55℃,10.0-24.0MPa范围内测定了超临CO2对树兰花浸膏的溶解度,研究了传质过程的影响因素。树兰花适当粉碎,能有效地提高过程传质速率,提高产品收率;超临界CO2中溶质浓度随CO2的停留时间增加而增加。  相似文献   

2.
超临界CO2的溶剂特性对脂肪酶催化反应的影响   总被引:5,自引:0,他引:5  
分别用溶解度参数和介电常数表征超临界流体的溶剂特性,并计算了不同压力下二氧化碳的溶解度参数和介电常数。测定了不同压力下脂肪酶催化月桂酸和正丁醇酯化反应的最大反应速率和米氏常数,研究了溶解度参数δ和介电常数ε对最大反应速率Vm的影响,并比较好地进行了关联:ln[Vmax/(mmolh-1g-1)]=4.465-0.153(δ/MPa0.5),ln[Vmax/(mmolh-1g-1)]=4.187-8.318(ε-1)/(ε+1).从而通过溶剂特性将压力这一操作条件直接与反应动力学相联系。  相似文献   

3.
用超临界流体萃取方法处理多氯联苯污染物   总被引:1,自引:0,他引:1  
测定了三种多氯联苯(PCBs)同系物:4,4’-二氯联苯,2,3’,4’,5-四氯联苯,2,2’,3,3’,4,4’-六氯联苯在超临界CO2中的溶解度。实验是用静法在一个带可视窗的高压平衡池内进行。实验的压力为9~45MPa,温度为308.1~329.1K。同时研究了用超临界流体萃取技术处理被PCBs污染的固体物的方法。测定其萃取PCBs的传质速率及有效性,实验压力为7.5~60MPa,实验温度为305.5~313.1K.CO2流率为0.7g/s。  相似文献   

4.
紫苏籽油超临界萃取最佳工艺条件的研究   总被引:10,自引:0,他引:10  
采用正交试验确定了超临界CO2萃取紫苏籽油的工艺条件,并与传统的溶剂萃取法进行比较,实验结果表明,萃取的最佳条件为:压力20MPa,温度40℃,时间6h,CO2流量为30L/h,草取率可达37.2%,α-亚麻酸含量为73.1%,比传统的溶剂萃取法有很大的优越性。  相似文献   

5.
对超临界CO_2流体萃取卵黄磷脂及其机制进行了研究,超临界CO_2在丙酮和瓷粉作用下,在35MPa、40℃条件下萃取3h,可脱除蛋黄粉中98.6%的卵黄油。在40MPa、50℃条件下,用10wt%乙醇夹带,卵黄中磷脂的提取率最高,为27.28%。  相似文献   

6.
用超临界CO2(SC-CO2)萃取伏令夏橙皮中的精油,确定萃取的最佳实验条件为36℃,11.0MPa。同时,对SC-CO2萃取所得到的精油进行有机化学成分及无机微量元素的分析,确认该精油的品质优良。  相似文献   

7.
用超临界CO2(SC-CO2)萃取伏令夏橙皮中的精油,确定萃取的最佳实验条件为36℃,11.0MPa,同时,对SC-CO2萃取所得到的精油进行有机化学成分及无机微量元素的分析,确认该精油的品质优良。  相似文献   

8.
近日,中科院长春应用化学研究所“苯甲酸加氢合成环己基甲酸的新方法”获国家发明专利授权。本发明公开了一种苯甲酸加氢合成环己基甲酸的方法。苯甲酸在负载型过渡金属铑催化剂的存在下,在无溶剂,超临界二氧化碳及环己基甲酸中,在温和的反应条件(温度20-80℃、压力1-10MPa)下与氢气接触发生环催化反应;反应后利用环己基甲酸在超临界二氧化碳中的溶解度将其进行萃取,  相似文献   

9.
目前一种新的纺织物染色方法正在向着实用阶段推进,那就是用二氧化碳作溶剂对纺织物进行染色,二氧化碳在31℃和73个大气压下处于超临界状态(其状态介于气体和液体之间)。如果进一步加压,二氧化碳就变为液体,染料在液态二氧化碳中的溶解度将大大提高,  相似文献   

10.
开发了迅速测定超临界流体-聚合物混合物系中的无限稀释气液平衡比 率(以下简称气液平衡比率)的系统.该系统由气液分配色谱与石英压电法两 套实验装置构成.应用该系统在温度313.2、333.2K,压力8 MPa以下的条件 下测定了苯与甲苯在二氧化碳-聚醋酸乙烯酯(PVAc)混合物系中的气液平 衡比率.两温度下的实验值都呈现极小值,并在压力8 MPa附近有大小交替 趋势.使用Sanchez-Lacombe状态方程对气液平衡比进行了推算,推算中使 用的各二元混合物系的相互作用参数是通过关联各物系的气液平衡实验值 获得的.推算值与实验值良好一致.  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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