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杜仲中环烯醚萜类化合物的提取工艺研究(英文)

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天然产物研究与开发 2003年第6期15卷 521-527页

作者：彭密军周春山董朝青雷启福贺前锋吉首大学湖南张家界427000 中南大学化学化工学院长沙410083

本文研究了杜仲中具有生物活性的环烯醚萜类化合物的最佳提取工艺。采用正交设计表L16(4 5) ,以提取时间、提取温度、提取次数、提取剂A的浓度及料液比为因素进行实验优化。桃叶珊瑚甙的含量由分光光度法测得 ,京尼平甙酸和京尼平甙的... 详细信息

本文研究了杜仲中具有生物活性的环烯醚萜类化合物的最佳提取工艺。采用正交设计表L16(4 5) ,以提取时间、提取温度、提取次数、提取剂A的浓度及料液比为因素进行实验优化。桃叶珊瑚甙的含量由分光光度法测得 ,京尼平甙酸和京尼平甙的含量通过高效液相色谱法测定。根据试验结果 ,提取桃叶珊瑚甙的最佳工艺是 :70℃下提取三次 ,每次 0 .5小时 ,溶剂A的浓度为 80 % ,料液比为 1:12。而京尼平甙和京尼平甙酸的最佳提取工艺为 :在 70℃下提取一次 ,提取时间为 1小时 ,溶剂A的浓度为5 0 % ,料液比也为 1∶12。在此工艺条件下 ,选取了较佳的提取原料。实验表明在实际应用中 ,应根据提取目标和原材料选择较好的提取工艺。

关键词：杜仲环烯醚萜类化合物正交设计提取因素提取工艺

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四氧化三锰磁性材料制备

韶关学院学报 2002年第9期23卷 57-61页

作者：何秋星陈权启黄可龙韶关学院化学系广东韶关512005 中南大学化学化工学院湖南长沙410083

介绍了四氧化三锰的制备、检测方法及其相关理论研究 .按制备工艺中所用原料形态的不同 ,可分为固相合成和液相合成方法 .同时。

关键词：四氧化三锰固相合成液相合成纳米材料

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pH和加料方式对选择性沉淀分离镍锰的影响

湿法冶金 2011年第4期30卷 298-303页

作者：何显达许开华陈尧陈艳红王勤叶红齐湖北省城市矿产资源循环利用工程技术研究中心荆门市格林美新材料有限公司湖北荆门448124 中南大学化学化工学院湖南长沙410083

根据Ni(Ⅱ)-Mn(Ⅱ)-NH3-CO32--H2O体系的热力学,绘制出溶解度、过饱和度及pH的变化规律图,确定了选择性沉淀分离镍、锰的工艺条件。热力学分析结果表明,在pH≈10条件下,采用反向(金属剂加入到沉淀剂中)加料方式,有利于锰的选择性沉淀。... 详细信息

根据Ni(Ⅱ)-Mn(Ⅱ)-NH3-CO32--H2O体系的热力学,绘制出溶解度、过饱和度及pH的变化规律图,确定了选择性沉淀分离镍、锰的工艺条件。热力学分析结果表明,在pH≈10条件下,采用反向(金属剂加入到沉淀剂中)加料方式,有利于锰的选择性沉淀。沉淀分离试验结果证实了热力学预测结果,所得碳酸锰沉淀粉末的分散性和洗涤性能良好,镍损失率仅1.0%,锰沉淀率高达99.7%。

关键词：选择性沉淀热力学分析镍锰分离溶解度过饱和度

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肌苷发酵液的陶瓷膜过滤研究

湖南科技大学学报（自然科学版） 2004年第2期19卷 91-94页

作者：曾坚贤邢卫红徐南平湖南科技大学化学化工学院南京工业大学膜科学技术研究所南京210009

以工业化陶瓷膜考察了肌苷发酵液在不同浓缩比下的拟稳定通量、粘度及湿固含量变化,在此基础上,将发酵液进、出口调换,可使膜通量提高;分析了水洗方式对肌苷含量及膜通量的影响;探讨了膜的污染机理,提出了有效的膜清洗方法.结果表明:20... 详细信息

以工业化陶瓷膜考察了肌苷发酵液在不同浓缩比下的拟稳定通量、粘度及湿固含量变化,在此基础上,将发酵液进、出口调换,可使膜通量提高;分析了水洗方式对肌苷含量及膜通量的影响;探讨了膜的污染机理,提出了有效的膜清洗方法.结果表明:200nm膜适宜于肌苷发酵液的膜过滤,按流加率4%加入洗水有利于菌体的洗涤,不可逆污染阻力Rf在总阻力中占主要地位,有效的化学清洗方法是:用1%NaOH和0.2%NaClO混合溶液清洗膜40min后,再以0.5%HNO3溶液清洗5min,膜通量可迅速恢复.图7,表2,参8.

关键词：肌苷发酵液陶瓷膜过滤膜清洗膜污染生物化学药品

Synthesis and purification of trialkyl compounds of gallium and indium

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Rare Metals 2002年第1期21卷 1-6页

作者： SHU Wangen, ZHOU Zhongcheng and LI Xiong chemistry and chemical engineering college, central south university, changsha 410083, china chemistry and chemistry engineering college Central South University Changsha 410083 chemistry and chemical engineering college Central South University Changsha 410083

The The research progress in trialkyl compounds of gallium andindium was discussed from two aspect, one was the chemical synthesisof the compounds and the other was the purification of them. Thereare three synthesis routes be- ing reported in the first aspect, *** route staring form pure metal, the route starting from the puremetal trihalides, and the electrochemical route. In the secondaspect, the purifying methods of decomposition-distillation and zonerefining were reviewed.

关键词： trialkyl compounds gallium nd indium synthesis purification

Boron rings containing planar octa- and enneacoordinate cobalt, iron and nickel metal elements

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Science china chemistry 2008年第7期51卷 607-613页

作者： LUO Qiong School of chemistry and chemical engineering, central south university, changsha 410083, china School of chemistry and chemical engineering Central South UniversityChangsha 410083China

For a series of boron rings with planar hyper-coordinate 8th group transition metal atoms, singlet 1FeB8-2, multiplet kFeB9n (n = -1, k = 1; n = 0, k = 2), singlet 1CoB8n(n = -1, +1, +3), multiplet kCoB9n (n = +1, k = 2; n = 0, k = 1) and singlet 1NiB9+, the geometry structures have been optimized to be local minima on corresponding potential hyper-surfaces. The electron structures are discussed by orbital analysis and the aromaticity is predicted by nucleus-independent chemical shifts calculation at both the B3LYP/6-311+G* and BP86/6-311+G* levels of theory, respectively. The results suggest that all these structures with high symmetry planar geometries are stable and have aromatic properties with six π valence electrons.

关键词： planar hyper-coordinate transition metal DFT

Electrochemical characteristics of amorphous MgTi_xNi(x = 0,0.1,and 0.2) hydrogen storage alloys

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Rare Metals 2010年第5期29卷 486-490页

作者： LIU Suqin,ZHAO Wenjuan,HUANG Kelong,and HUANG Hongxia college of chemistry and chemical engineering,central south university,changsha 410083,china college of chemistry and chemical engineering Central South University Changsha China

MgTixNi （x = 0, 0.1, and 0.2） alloys were successfully prepared by mechanical alloying （MA）, and the influence of milling time on the electrochemical characteristics of the electrodes was discussed. MgTixNi alloys after 90 h milling displayed the best electrochemical performance The X-ray diffraction patterns showed that the alloy ball-milled for 90 h was amorphous with a widened diffraction peak. The charge-discharge tests indicated that these alloys had good electrochemical activation properties, and the MgTi0.2Ni alloy electrode exhibited the best cycle performance. The initial discharge capacity of the MgTi0.2Ni alloy reached up to 401.1 mAh·g^-1, and the retention rate of capacity was 31.0% after 30 cycles, much higher than that of MgNi （17.3%）. The Tafel polarization curves revealed that Ti addition could enhance the anticorrosion performance of these alloys in alkali solution, which was responsible for the ameliorated cyclic stability of these alloy electrodes.

关键词： hydrogen storage alloys titanium electrochemical properties mechanical alloying

Effects of Oxalic Acid Addition on the Hydrothermal Synthesis of Kaolinite

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Journal of central south university 2000年第1期12卷 34-36页

作者： LIU Su qin,HUANG Ke long (college of chemistry and chemical engineering, central south university of Technology, changsha 410083, china) 1. college of chemistry and chemical engineering Central South University of Technology 410083 Changsha China

Kaolinite was hydrothermally synthesized from alumina gel and silicate by dissolving alumina gel in oxalic acid before it was mixed with silicate, effects of the amount of addition on the species of synthetic products were discussed. The reaction product was characterized by X ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that analcite is the only phase of the reaction solution without oxalic acid, the proportion of kaolinite in product increases with the amount of addition, and kaolinite is the main species when the molar ratio of oxalic acid to alumina reaches 0.6∶1.0. This is because oxalic acid addition is beneficial to the formation of kaolinite through changing the coordination number of aluminium from four to six, while the mixture of alumina gel, before it was dissolved in oxalic acid with silicate interfered with the crystallization of kaolinite.

关键词： kaolinite hydrothermal synthesis oxalic acid

Drag reduction of flow boiling with polymer additives

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Journal of central south university of Technology 2001年第2期8卷 143-146页

作者： QIU Yun ren 1,CHEN Wei ping 2,SI Qin 3 (1.college of chemistry and chemical engineering, central south university, changsha 410083, china 2.Editorial Office of Journal of central south university, changsha 410083, china 3.college of chemical E 1. college of chemistry and chemical engineering Central South University 410083 Changsha China 2. Editorial Office of Journal of central south university 410083 Changsha China 3. college of chemical engineering Tianjin University 300072 Tianjin China

The drag reducing effect of polymer additive aqueous solution was investigated in flow boiling, and the polymer additives were two kinds of polyacrylamide (PAM) with relative molecular mass about 2.56×10 6 and 8.55×10 6. The frictional pressure drop was calculated according to the measured total pressure drop. The results show that the flow drag of flow boiling is reduced by adding a small amount of PAM to water when heat flux is in the range of 15.1 kW·m -2 to 47.0 kW·m -2 , when the mass fraction of PAM is higher than 2.0×10 -5 , the drag reducing effect is obvious. Drag reducing effect of PAM, whose relative molecular mass is 8.55×10 6, is slightly better than that of 2.56×10 6 at the same mass fraction, and the greater the flow rate of the additive solution, the better the effect of the drag reduction.

关键词： polymer additive flow boiling drag reduction pressure drop