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基于混合聚类算法的动态R-树 被引量:16
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作者 黄继先 鲍光淑 夏斌 《中南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2006年第2期366-370,共5页
针对动态R-树是通过动态插入算法建立起来的,其节点分裂算法的性能直接影响到R-树的性能和查询效率的问题,为了使动态R-树适应多维复杂空间数据的要求,提出一种用于实现R-树节点分裂的混合聚类算法(HCR),它建立在普通聚类算法的基础上,... 针对动态R-树是通过动态插入算法建立起来的,其节点分裂算法的性能直接影响到R-树的性能和查询效率的问题,为了使动态R-树适应多维复杂空间数据的要求,提出一种用于实现R-树节点分裂的混合聚类算法(HCR),它建立在普通聚类算法的基础上,并进行了一系列扩充。针对空间对象的均匀分布与不均匀分布,HCR算法在实现R-树节点分裂时分别采用不同的聚类准则以提高其聚类效果和查询效率。此外,还将HCR算法与其他算法进行对比实验,结果表明该算法具有较高的查询效率。 展开更多
关键词 空间索引 R- 混合聚类算法 cr-树
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Solvent impregnated resin prepared using ionic liquid Cyphos IL 104 for Cr(VI) removal 被引量:6
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作者 杨秀云 张建苹 +3 位作者 郭琳 赵贺 张阳 陈继 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第12期3126-3130,共5页
Ionic liquid (IL) trihexyl (tetradecyl) phosphonium bis 2,4,4-trimethylpentylphosphinate (Cyphos IL 104) was impregnated on XAD-7 resin. The solvent impreganated resin (SIR) was prepared and applied in Cr(VI) removal.... Ionic liquid (IL) trihexyl (tetradecyl) phosphonium bis 2,4,4-trimethylpentylphosphinate (Cyphos IL 104) was impregnated on XAD-7 resin. The solvent impreganated resin (SIR) was prepared and applied in Cr(VI) removal. The morphology and the thermal stability of the resins were explored. The effects of equilibrium time and initial pH value on Cr(VI) adsorption were investigated. Adsorption isotherm, separation and desorption of the SIR, and selectivity of SIR were also explored. The results show that Cyphos IL 104 exists in the inner XAD-7 resin, and the optimum pH value range of the SIR for Cr(VI) extraction is 0 to 2. When NaOH used as desorption solution, the Cr(VI) can be effectively desorbed from the SIR. 展开更多
关键词 solid-liquid extraction Cyphos IL 104 CR(VI) RESIN adsorption isotherm separation DESORPTION
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Adsorption and desorption properties of D318 resin for Cr(Ⅵ) 被引量:1
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作者 舒增年 熊春华 《Journal of Central South University》 SCIE EI CAS 2009年第3期405-409,共5页
The adsorption capability of D318 resin for Cr(Ⅵ) was investigated by chemistry analysis. Experimental results show that D318 resin has the best adsorption ability for Cr(Ⅵ) at pH=3.16 in HAc-NaAc medium. The st... The adsorption capability of D318 resin for Cr(Ⅵ) was investigated by chemistry analysis. Experimental results show that D318 resin has the best adsorption ability for Cr(Ⅵ) at pH=3.16 in HAc-NaAc medium. The statically saturated adsorption capacity of the resin is 265.4 mg/g. The thermodynamic adsorption parameters, enthalpy change AH and free energy change AG298 of the adsorption reaction are 4.81 and -5.16 kJ/mol, respectively. The apparent activation energy Ea is 22.4 kJ/mol. The adsorption behavior obeys the Freundlich isotherm. The molar coordination ratio of the functional group of resin to Cr(Ⅵ) is 3:2. Cr(Ⅵ) adsorbed on D318 resin can be eluted by 5%NaOH-5%NaCl quantitatively. 展开更多
关键词 Cr(Ⅵ) D318 resin ADSORPTION DESORPTION DYNAMICS THERMODYNAMICS
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The preparation of supported ionic liquids (SILs) and their application in rare metals separation 被引量:4
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作者 ZHU LiLi GUO Lin +2 位作者 ZHANG ZhenJiang CHEN Ji ZHANG ShaoMin 《Science China Chemistry》 SCIE EI CAS 2012年第8期1479-1487,共9页
This review summarizes the preparation methods of support ionic liquids (SILs) and their applications in rare metals separation The rare metals separation includes the recovery of high value metal ions and the remov... This review summarizes the preparation methods of support ionic liquids (SILs) and their applications in rare metals separation The rare metals separation includes the recovery of high value metal ions and the removal of heavy metal ions from wastewater. SILs can be used as a kind of highly efficient multifunctional separation materials. The preparation methods of SILs include chemical immobilization technique in which ILs moieties are supported on solid supports via covalent bonds and physical immobilization techniques in which ILs are immobilized on solid supports via physical method such as simple im- pregnation, sol-gel method. According to the difference of solid supports, this review summarizes the application of polymer supported ionic liquids (P-SILs), silica based material supported ionic liquids (SM-SILs) and membrane supported ionic liq- uids (M-SILs) in rare metals separation, P-SILs and SM-SILs prepared by chemical method with N-methylimidazolium group can be used as highly efficient anion exchangers with high thermal stability and good chemical stability for adsorption of Cr(Ⅵ), Re(Ⅶ), Ce(Ⅳ). P-SILs prepared via simple impregnation afforded IL functionalized solvent impregnated resins (SIRs) which showed high separation efficiency and selectivity in the separation of rare earths(Ⅲ) (REs(Ⅲ)). SM-SILs prepared via sol-gel method with IL doped in the support as porogens or extractant show high removal efficiencies and excellent stability for the separation of RE(Ⅲ), Cr(Ⅲ) and Cr(Ⅵ). M-SILs with IL as plasticizer or carrier show improved stability, high perme- ability coefficient and good selectivity for Cr(VI) transport. Different supports and different supporting methods were suffi- ciently compared. Based on the different practical application, different forms of SILs can be prepared for separation of rare metals with high separation efficiency and selectivity. 展开更多
关键词 supported ionic liquid SEPARATION rare metals rare earth CHROMIUM
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