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超临界CO_2中苯甲酸与乙醇和二甲基亚砜的相互作用
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作者 柯杰 金顺子 +2 位作者 韩布兴 闫海科 沈德言 《物理化学学报》 SCIE CAS CSCD 北大核心 1996年第11期986-989,共4页
在35.0℃、12.6MPa条件下,用红外光谱法研究了超临界CO2中苯甲酸与乙醇和二甲基亚砜的相互作用.结果表明,在纯超临界CO2中,苯甲酸以单体和二聚体的形式存在.体系中有乙醇或二甲基亚砜存在时,这些强极性物质与苯甲酸形成氢键缔合... 在35.0℃、12.6MPa条件下,用红外光谱法研究了超临界CO2中苯甲酸与乙醇和二甲基亚砜的相互作用.结果表明,在纯超临界CO2中,苯甲酸以单体和二聚体的形式存在.体系中有乙醇或二甲基亚砜存在时,这些强极性物质与苯甲酸形成氢键缔合体,并且非缔合苯甲酸的浓度随乙醇浓度增加而减小. 展开更多
关键词 苯甲酸 乙醇 二甲基亚砜 二氧化碳 超临超界流体
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Advances in Supercritical Fluid Crystallization 被引量:1
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作者 任聪 《Agricultural Science & Technology》 CAS 2016年第6期1422-1428,1454,共8页
The supercritical fluid crystallization technique is a novel technology for preparing ultrafine particles. This paper introduced the concept and features of the technique with an emphasis on three kinds of supercritic... The supercritical fluid crystallization technique is a novel technology for preparing ultrafine particles. This paper introduced the concept and features of the technique with an emphasis on three kinds of supercritical fluid crystallization techniques, i.e. rapid expansion of supercritical solutions, supercritical fluid anti-solvent and particles from gas saturated solutions Some questions and the prospect of this technique were also discussed. 展开更多
关键词 Supercritical fluid: Rapid expansion of supercritical solutions Supercritical fluid anti-solvent Particles from gas saturated solutions
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Dynamic Supercritical Fluid Devolatilization of Polymers 被引量:3
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作者 叶树明 蒋凯 +1 位作者 蒋春跃 潘勤敏 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2005年第6期732-735,共4页
A number of studies have been reported on the applications of supercritical fluids to polymeric processes. The presence of volatiles can affect the end-use properties of polymer materials. Therefore, these volatiles m... A number of studies have been reported on the applications of supercritical fluids to polymeric processes. The presence of volatiles can affect the end-use properties of polymer materials. Therefore, these volatiles must be reduced to a level below the maximum permissible limit. Conventional heat-relevant techniques for polymer devolatilization sometimes have limited effectiveness. Devolatilization with supercritical fluids, however, can enhance removal of volatiles from polymers. A model for diffusion-limited extraction is used to characterize dynamic supercritical fluid devolatilization of spherical polymer particles. The rate of supercritical fluid devolailization for styrene/polystyrene system is measured at 343 K and 18 MPa and at CO2 flow rate of 1.93, 3.27 and 5.62 L·min^-1, respectively. The model analysis, which is consistent with experimental results, indicates that the supercritical fluid devolatilization is not solubility-limited but diffusion-limited when CO2 flow rate is above 4.00 L·min^-1. 展开更多
关键词 supercritical fluid devolatilization supercritical CO2 diffusion coefficient STYRENE POLYSTYRENE
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Combination of Supercritical Fluid Extraction with Ultrasonic Extraction for Obtaining Sex Hormones and IGF-1 from Antler Velvet 被引量:6
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作者 周冉 李淑芬 张大成 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2009年第3期373-380,共8页
Supercritical CO2 (SC-CO2) extraction technology and ultrasonic technology were used to extract two active sex hormones, estradiol and progesterone, and insulin-like growth factor-1 (IGF-1) from antler velvet. The eff... Supercritical CO2 (SC-CO2) extraction technology and ultrasonic technology were used to extract two active sex hormones, estradiol and progesterone, and insulin-like growth factor-1 (IGF-1) from antler velvet. The effects of SC-CO2 extraction condition on the extraction yield and content of sex hormones, the ultrasonic extrac-tion condition on the content of IGF-1 and the SC-CO2 extraction condition on the activity remaining of IGF-1 were studied. The optimal conditions were obtained. The experimental results showed that, in presence of 75% ethanol as the co-solvent, the mean yield and content of estradiol and progesterone were 87.67 pg·g-1 and 1224.10 pg·g-1, 12.38 ng·g-1 and 354.06 ng·g-1, respectively, with extraction pressure of 30 MPa, temperature of 35°C, extraction time of 30 min and CO2 consumption of 15 L·g-1 at the flow rate of 2.0 L·min-1. The highest content of IGF-1 was 7425.75 ng·g-1 antler velvet residue, when the pH10 ammonia-ammonium chloride buffer solution was used as the solvent, the ratio of solvent to sample was 20/1 (volume/mass), the extraction temperature was 0-35°C, and the ex-traction time was 4×15 min. Under these conditions, 93.68% activity remaining of IGF-1 in the residue was ob-tained, while little IGF-1 activity exists in traditional residue. The experimental results indicate that the technology of SC-CO2 with co-solvent is of advantage for getting high content sexual hormones and keeping high activity of IGF-1 in the residue, which can not be achieved by traditional extraction methods. 展开更多
关键词 antler Velvet supercritical extraction estradiol progesterone insulin-like growth factor-1
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Indelible Rules of Josephson Coupling Energy and Zero-Point Energy in High-Tc Cuprates
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作者 LIUFu-Sui CHENWan-Fang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第4期629-631,共3页
This paper shows that the Josephson coupling energy and the zero-point energy have indelible rules on the superfluid density and the superconductivity in the high-T<SUB>c</SUB> cuprates. This paper also sh... This paper shows that the Josephson coupling energy and the zero-point energy have indelible rules on the superfluid density and the superconductivity in the high-T<SUB>c</SUB> cuprates. This paper also shows that the values of T<SUB>c</SUB> at underdoped and overdoped regions are determined by the damage conditions of the phase coherence in the classical and the quantum XY-models, respectively. 展开更多
关键词 HIGH-T-C CUPRATES superfluid density Josephson coupling zero-point energy
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Supercritical extraction to obtain vetiver (Vetiveria zizanioides L. Nash) extracts from roots cultivated hydroponically
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作者 Camila G.Pereira Isabela P.Gualtieri +1 位作者 Nilson B.Maia M.Angela A.Meireles 《Journal of Agricultural Science and Technology》 2008年第10期44-50,共7页
We determined the global yield and composition of extracts from vetiver roots cultivated hydroponically. We extracted roots of two varieties collected at different times after planting. The extracts were obtained by s... We determined the global yield and composition of extracts from vetiver roots cultivated hydroponically. We extracted roots of two varieties collected at different times after planting. The extracts were obtained by supercritical fluid extraction (SFE); we also estimated manufacturing costs. Constituents were quantified by gas-chromatography/time ionization detection (GC-FID). Results demonstrated the efficacy of a hydroponic system in producing vctiver with a high root extract content. The largest yield was obtained from roots collected on days 132 and 92 after planting from varieties National (1.41%) and Bourbon (1.28%), respectively. The major compounds present in the extract were khusimoi, isovalencenol, alpha-vetivone and beta-vetivone. To determine the economic viability of producing these extracts, manufacturing costs were estimated using a simplified methodology. The manufacturing costs were US$ 22.26/kg and US$ 24.26/kg for varieties national and Bourbon, respectively. 展开更多
关键词 manufacturing cost HYDROPONICS supercriticalfluid extraction Vetiveria zizanioides
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