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1.
用脂肪酸制备了乙撑双(二甲基)季铵盐基双脂肪酸甲酯(B)及乙撑双(二甲基)季铵盐基双脂肪酸钠盐(C),用红外光谱对其结构进行了表征.经测定,分别用十二酸和十四酸制备的B1和B2其临界胶束浓度(cmc)分别为1.4×10-4和2.2×10-4 mol/L,其表面张力(γcmc)分别为30.5和37.8 mN/m;C1和C2的cmc分别为7.8×10-5和3.0×10-4 mol/L,γcmc分别为28.9和36.9 mN/m.结果表明,与普通表面活性剂相比,双子表面活性剂B1和B2的cmc要低1~2个数量级,γcmc也低了2~9个mN/m;C1、C2的cmc仅为普通表面活性剂的1/60~1/230,而γcmc相差不大.  相似文献   

2.
深层发酵香菇水溶性胞外多糖的分离纯化及性质分析   总被引:1,自引:0,他引:1  
香菇(Lentinusedodes)CL-2深层发酵上清液经乙醇沉淀、除蛋白、透析、DEAE-纤维素(DE-32)和SephadexG-200凝胶柱层析得到纯的水溶性胞外多糖(HEP).DNS法检测和IR分析证实,HEP为多糖类物质,且在200~400um近紫外区不吸收.经PC、GC、IR和甲基化分析,确定其基本结构是以β-1,4键连接为主链并具有β-1,6键支链的甘露葡聚糖.同时还具有少量的β-1,2和β-1,3键.葡萄糖和甘露糖的摩尔比为1:0.0852.  相似文献   

3.
小茴香萃取物中脂肪酸成分的GC-MS分析   总被引:1,自引:0,他引:1  
对宁夏固原种植的小茴香籽油用正已烷进行了回流提取物,萃取物经皂化和甲酯化反应处理后,利用气相色谱-质谱(GC-MS)进行分析,鉴定了产物中的脂肪酸组分,结果表明,17种脂肪酸中,含量最高的是十八碳烯-5-酸(78.562%),其次是十八碳二烯酸(8.352%)、棕榈酸(7.259%)和硬脂酸(2.103%)。  相似文献   

4.
棒束孢霉胞外多糖的纯化   总被引:4,自引:0,他引:4  
棒束孢霉发酵上清液经减压浓缩、醇析、蛋白酶法与Sevag法结合脱蛋白、逆向流水透析和DEAE-SephadexA-50柱层析等步骤,获得了胞外纯多糖。用TLC、GC及IR分析表明,该多糖链由D-甘露醇和D-半乳糖组成。  相似文献   

5.
以可溶性淀粉为原料,经水热处理、产物的高温碳化制备碳微球;并以β-环糊精和碳微球为原料经反相乳液法制备β-环糊精/碳微球复合材料;利用红外光谱、扫描电子显微镜、X射线光电子能谱、X射线衍射等手段对产物的结构和性质进行了表征。结果表明:以可溶性淀粉为原料制得了粒径约5μm的单分散碳微球;同时也成功地制备了表面光滑、粒径约15μm的β-环糊精/碳微球复合材料。  相似文献   

6.
短裙竹荪菌丝体糖蛋白DdGP-3P3纯化及性质研究   总被引:4,自引:0,他引:4  
短裙竹荪菌丝体经热水抽提,乙醇分级沉淀,级分3经DEAE-Cellulose柱层析纯化得到短裙竹荪菌丝体糖蛋白DdGP-3P3。经测定该糖蛋白为均一组分,相对分子质量为113KDa,红外光谱呈现出典型的多糖吸收峰,含有β-型糖苷连接键。β-消去反应测定,该糖蛋白中糖和蛋白质的连续键为O-型糖肽键。纸层析和气相层析分析得知DdGP-3P3含有D-葡萄糖(D-glucose)、D-甘露糖(D-Mannose)和D-半乳糖(D-galactose),其摩尔比为2.01:1.00:1.23。氨基酸分析表明它含有16种氨基酸。  相似文献   

7.
设计一个270bp的丙型肝炎病毒(HCV)复合多表位抗原基因(PCX),与β-半乳糖苷酶(GZ)基因融合后,在高浓度肉汤培养基中,于转接1%量后3.25h,用终浓度为1mmol/LIPTG诱导4h发酵表达,其表达量最高,约占50%总蛋白量,表达产量GZ-PCX以包含体形式存在.利用改良的包含体纯化及溶解方法,可获得溶解率>90%,纯度为96.2%的产物GZ-PCX,且包含体溶解产物较好保存其蛋白酶活.对PBS/EDTA透析,GZ-PCX蛋白的β-半乳糖苷酶活性可升高4倍,对H2O/EDTA透析其活性则明显下降.  相似文献   

8.
以月桂醇、环氧氯丙烷、二甲胺、氯乙酸经三步反应合成出一种新型甜菜碱型沥青乳化剂.确定了第一步合成2-(十二烷氧基亚甲基)环氧乙烷的最佳反应条件,其收率为75.7%.利用红外光谱对3种产物结构进行了表征,利用在线红外光谱技术对第一步合成2-(十二烷氧基亚甲基)环氧乙烷的反应进行追踪分析,检测出中间体.基于以上实验数据,提出了合理的反应机理.最终产物的临界胶束浓度为8.8×10-5mol/L,在临界胶束浓度下的表面张力为21.2 mN/m.该乳化剂属于中裂型沥青乳化剂.  相似文献   

9.
核盘菌多糖是由核盘菌(Sclerotinia sclerotiorum)通过深层发酵产生的一种胞外多糖。本文通过单因子试验和正交试验对其摇瓶发酵条件进行了优选,使SSG的产率达到12.03g/L,碳源转化率达40.1%;纸层析和红外光谱分析表明,SSG是一种由β-键连接的葡聚糖,其水溶液具有良好的增粘性和假塑性。  相似文献   

10.
采用酯化反应无需有机溶剂为介质、以碳基固体酸作酯化反应催化剂、磺化反应不外加相转移催化剂在常压下反应的新方法合成了乙二醇双子琥珀酸2-甲基戊基酯磺酸钠,最佳工艺条件为:单酯化反应,n(乙二醇):n(顺酐):l_00:2.10,催化剂碳基固体酸用量为顺酐质量的2%,于100℃反应4.7h,酯化率99.02%(质量分数);双酯化反应。n(2-甲基-l-戊醇):n(顺酐)=1-30:1.00,于210℃反应1.2h,酯化率95.34%(质量分数);磺化反应,n(亚硫酸氢钠):n(顺酐):1.05:1.00。于油浴120℃反应3.2h,磺化率100.64%(质量分数).对产物结构进行了IR光谱表征,测定了产物性能:CMC为2.5×10。mol/L,7cMc为27.79mN/m,乳化力为11.5min,渗透力为6s,耐硬水力为13.5min.比较了碳基固体酸和无水乙酸钠、对甲苯磺酸对酯化反应的催化效果,结果表明:碳基固体酸对酯化反应的催化效果好.且易于分离.  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.
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   

14.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

15.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  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.
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   

18.
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   

19.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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