排序方式: 共有48条查询结果,搜索用时 125 毫秒
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Ke-long Huang~ 《高分子科学》2008,(1):1-11
The adsorption of Fe(Ⅲ)ions from aqueous solution by chitosan alpha-ketoglutaric acid(KCTS)and hydroxamated chitosan alpha-ketoglutaric acid(HKCTS)was studied in a batch adsorption system.Experiments were carried out as function of pH,temperature,agitation rate and concentration of Fe(Ⅲ)ions.The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms and isotherm constants were determined.The Langmuir model agrees very well with experimental data.The pseudo-first-order and second-order kinetic models were used to describe the kinetic data and the rate constants were evaluated.The dynamical data fit well with the second-order kinetic model.The pseudo second-order kinetic model was indicated with the activation energy of 19.61 and 7.98 kJ/mol for KCTS and HKCTS,respectively.It is suggested that the overall rate of Fe(Ⅲ)adsorption is likely to be controlled by the chemical process.Results also showed that novel chitosan derivatives(KCTS and HKCTS)were favorable adsorbents. 相似文献
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Delay discrete integral inequalities with n nonlinear terms in two variables are discussed, which generalize some existing results and can be used as powerful tools in the analysis of certain partial difference equations. An application example is also given to show boundedness of solutions of a difference equation. 相似文献
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采用喷雾热解两段法制备了SrAl2O4∶Eu2+ ,Dy3+长余辉发光材料,并利用XRD、SEM、荧光长余辉亮度测试等方法分析了不同制备工艺条件下SrAl2O4∶Eu2+ ,Dy3+发光材料的结构、形貌以及发光性能的变化。结果表明:采用喷雾热解两段法可制备出球形SrAl2O4∶Eu2+ ,Dy3+长余辉发光材料,SrAl2O4∶Eu2+ ,Dy3+的晶体结构与α-SrAl2O4磷石英晶体结构相同。热解温度、还原温度、添加剂对产物的形貌、粒度分布、发光性能有较大影响。较之高温固相法,喷雾热解法制备的SrAl2O4∶Eu2+ ,Dy3+具有发光性能好、形貌好、粒度分布窄等优点。 相似文献
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对广义Rosenau-Burgers方程的初边值问题进行了数值研究,提出了新的两层隐式差分格式,得到了差分解的存在唯一性,并利用能量方法分析了该格式的二阶收敛性与无条件稳定性,并且给出数值算例进行验证. 相似文献
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以二氯化钯、联吡啶(bpy)、二乙酰丙酮合成了双核钯(Ⅱ)的新型固态三元配合物[{Pd(C10H8N2)}2(C10H12O4)][PF6]2,用元素分析、电导率、氢核磁共振谱、电喷雾质谱、红外光谱、电子光谱和荧光光谱对其进行了表征,确定了配合物的组成.利用热重-微分热重法(TG/DTG)讨论了配合物在氮气气氛中的热分解行为.结果表明:该配合物属于低自旋的平面正方形,配合物中离域π键和螯合环的形成使Pd-O和Pd-N键加强,配合物很稳定. 相似文献
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以SrCO3和Al2O3为原料,掺杂Eu2 和Dy3 ,采用高温固相法制备了SrAl12O19∶Eu2 ,Dy3 紫色荧光粉。当基质中nSr∶nAl=1∶12时,改变反应温度,通过X射线衍射图谱分析晶相的转变过程。反应温度分别为1150,1200,1250℃时,改变基质中的锶铝比(nSr∶nAl=1∶6~1∶18),探讨基质组成和反应温度对荧光粉发射光谱的影响。结果发现,随着基质中Al含量的增加和反应温度的升高,发射光谱从490nm蓝移至395nm。当nSr∶nAl=1∶12,反应温度为1250℃时,荧光粉的发光强度最大。该荧光粉无长余辉现象。 相似文献
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组合手性萃取拆分克伦特罗外消旋体 总被引:1,自引:1,他引:0
以D-二苯甲酰酒石酸(D-DBTA)和D-二对甲苯甲酰酒石酸(D-DTTA)的组合作为手性选择剂,研究克伦特罗对映体在水相和有机相中的萃取分配行为,优化了手性萃取条件,考察了组合手性选择剂的不同摩尔浓度比、有机溶剂、水相pH值和亲脂性阴离子BPh4-对手性萃取性能的影响,并测定了手性萃取拆分过程中的热力学函数.在优化的手性萃取条件下,有机相中的对映体过量值(e.e.%)可大于10%,而所使用的选择剂量相对大为降低.热力学数据分析表明,该手性萃取过程为焓控过程. 相似文献