共查询到20条相似文献，搜索用时 46 毫秒
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一、引言用超临界流体作为萃取剂来分离、提纯化合物就是新近发展的超临界流体萃取技术。它不仅能在化工领域中应用,而且已为石油、食品、煤炭、医药、烟草等工业所采用。国外的研究非常活跃,国内也已起步。该技术开发的一个重点就是其基础理论的研究,包括相平衡的计算,分离效率的确定等。超临界流体萃取与其它萃取过程一样,属于平衡分离过程,因而在论证其方案,确定工艺指标和设备设计中,都需要有此过程中涉及的相平衡数据。我们针对超临界流体萃取技术用于醇——水体系分离和用超临界CO_2回收石油过程中涉及的部分相平衡关系,用状态方程法进行关联计算,作为研究超临界流体萃取技术的出发点。选用十个含超临界CO_2的二元系进行计算,考察了有关状态方程的适用性。 相似文献
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用反相纸层析法在ＨＣ１体系中考察了Ｎ,Ｎ－二丁基甘氨酸对Ｌａ＾３＋、Ｓｍ＾３＋等４２种离子的萃取能力。实验表明,此萃取剂对Ｎｄ＾３＋、Ｇｄ＾３＋等１８种离子具有较强的萃取能力。 相似文献
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本文探讨了超临界CO2对微孔草的油萃取工艺，着重探讨了影响微孔草油提取的主要因素，温度，压力，时间，结果显示，用超临界CO2萃取方法提取微孔草油是可行的。 相似文献
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本文利用反相高效液相色谱法同时分离测定可乐型饮料中糖精、苯甲酸、咖啡因。色谱柱为ODS,以甲醇和0.02 mol/L浓度醋酸铵缓冲液作流动相进行梯度洗脱。流速为1ml/min,检测波长为230nm。样品经调至pH7过滤后直接进样。结合色谱保留时间对峰进行不停泵紫外光谱扫描,提高定性的准确性。外标法峰面积定量。对糖精、苯甲酸和咖啡因的回收率、标准偏差和变异系数分别为93.9、2.94、3.13;96.8、2.23、2.30;95.8、3.13、3.27。 相似文献
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生活废水中动植物油的快速测定 总被引：1，自引：0，他引：1
使用JDS-103型红外分光测油仪，测定水质中石油类和动植物油。通过条件实验确定了用标准曲线代替工作曲线，用一次定量萃取代替两次萃取定容，用直接流出比色代替无水硫酸钠过滤吸水后比色的快速测定方法。方法的精密度和准确度均达到国家标准要求，减轻了工作强度，节省了大量时间，适应了快速测定的要求。 相似文献
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目的:建立高效液相色谱法测定红碎茶中咖啡因的含量.方法:流动相:0.02mol/L醋酸铵-甲醇(75:25);色谱柱:Diamonsil ODS C185μm 200mm×4.6mm;检测波长:254nm;流速:1.4ml/min;进样量:20μl,外标法以峰面积定量,理论板数按咖啡因计算不低于3000.结果:咖啡因在5～25μg/ml范围内呈良好的线性关系(r＝1.0000),平均回收率为99.78%,RSD为0.53%(n=5).结论:本方法稳定,重现性好,收率好,结果准确,可作为红碎茶中咖啡因的含量测定方法. 相似文献
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通过超临界CO2萃取均匀设计实验和微波辅助萃取荷叶挥发油的正交实验比较，考察影响提取的主要图素，寻求最佳萃取工艺。 相似文献
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《中国科学院院刊(英文版)》2008,22(1):13-14
Aresearch project on the greenhouse cultivation of Swertia chirayita Buch Ham, a popular herbal drug used by the Tibetan people against liver and gallbladder diseases, recently passed the acceptance check by a panel of experts under the auspices of Qinghai Provincial S＆T Bureau. The feat was accomplished by researchers from the Lanzhoubased CAS Northwest Institute of Plateau Biology. 相似文献
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The research into the origins of domestic animals is of significance not only for understanding their development per se but also for making clear the human society evolution. Although there are evidences to show that pigs were independently domesticated in a variety of places throughout the world the detailed scenario of the origin dispersal of domestic pigs in East Asia remains unclear.…… 《中国科学院院刊(英文版)》2008,22(1):7-7
The research into the origins of domestic animals is of significance not only for understanding their development per se, but also for making clear the human society evolution. Although there are evidences to show that pigs were independently domesticated in a variety of places throughout the world, the detailed scenario of the origin and dispersal of domestic pigs in East Asia remains unclear. 相似文献
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Among the galaxy of research development organizations in northwest Beijing's Zhongguancun district known as China's Silicon Valley two are especially well-known to IT researchers: Microsoft Research Asia 《中国科学院院刊(英文版)》2008,22(1):47-49
Among the galaxy of research and development organizations in northwest Beijing＇s Zhongguancun district, known as China＇s Silicon Valley, two are especially well-known to IT researchers： Microsoft Research Asia （MSRA）, and, within a few blocks on the other side of the street, the CAS Institute of Automation （CASIA）. While most people in Chinese scientific organizations strive to move to a large foreign counterpart, Dr. Stan Z. Li （LI Ziqing） moves against the stream. 相似文献
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《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
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《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
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《中国科学院院刊(英文版)》2008,22(1):58-58
As a key component of the national initiative for basic S＆T data and infrastructure development, a nationwide survey on the lake water quality, volume and bio-resources has recently been kicked off. The move marks the systematic implementation of the secondround investigation of the country＇s lacustrine resources. 相似文献
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Bats the only mammals known to possess the real ability to fly have fascinated zoologists for a long time with their long-distance migration. How do they find their way home from an altitude of kilometers above sea level where their stunt of ultrasonic echolocation does not work?…… 《中国科学院院刊(英文版)》2008,22(1):3-4
Bats, the only mammals known to possess the real ability to fly, have fascinated zoologists for a long time with their long-distance migration. How do they find their way home from an altitude of kilometers above sea level, where their stunt of ultrasonic echolocation does not work？ Recent discoveries supported the theory that bats might be able to use magnetic clues to figure out their own position,just like what birds do. However, the latest results from a joint study by a group of researchers from the CAS, East China Normal University and University of Auckland reveal that bats apply an interesting strategy different from the one underlying birds＇ orientation technique, though they both are believed to derive information about their position from the subtle changes in the magnetic field of the Earth. 相似文献
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《中国科学院院刊(英文版)》2014,(3):252-252
<正>On February 12,2014,the international academic journal Cancer Research published an article online entitled"Latency Associated Nuclear Antigen of Kaposi's Sarcoma Associated Herpesvirus Promotes Angiogenesis through Targeting Notch Signaling Effector Hey1",as a result from the research conducted by Prof.LAN Ke’s lab at the Institut Pasteur of Shanghai,Chinese Academy of Sciences. 相似文献
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SONG Jianlan 《中国科学院院刊(英文版)》2014,(3):217-220
<正>Scientists from CAS and the Max Planck Society(MPG)met on May 13,2014 in Beijing to celebrate their four-decade-long ST cooperation and cherished friendship,anticipating further development of the bilateral relation.This partnership formally began four decades ago with a visit paid by then MPG President,Prof.Lüst to CAS,introduced CAS President BAI in his address at the celebration:"During the visit,CAS and MPG confi rmed the basic principles of cooperation,that is equality and mutual benefi ts for both sides,and reached agreement to develop a collaborative partnership."This occurred only two years after the establishment of the diplomatic relations between Germany and China,despite the shadow of the Cold War."Building up a partnership between Germany and 相似文献
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TANG Kun 《中国科学院院刊(英文版)》2014,(2):161-165
<正>The scientifi c goals of the Partner Group are to utilize large scale genomic polymorphism data to make fi ne inferences about human demographic history and various forms of natural selection in the human genome;and to understand the genetic basis and evolutionary mechanisms underlying the common variations in human facial morphology,both within and between populations. 相似文献