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1.
掺钕钙铝磷酸盐玻璃的光谱参数于亚勤,张思远,王庆元,盛桂云(中国科学院长春应用化学研究所长春130022)(长春冶金专科学校长春)关键词掺钕钙铝磷酸盐玻璃,光谱参数,Judd-Ofelt理论1960年第一台红宝石激光器问世后,1961年便出现了掺钕钡...  相似文献   

2.
二(叔丁基环戊二烯基)钕甲基配合物催化丙烯腈聚合   总被引:7,自引:0,他引:7  
任劲松  沈琪 《应用化学》1995,12(3):105-106
二(叔丁基环戊二烯基)钕甲基配合物催化丙烯腈聚合任劲松,扈晶余,沈琪(中国科学院长春应用化学研究所稀土化学与物理开放实验室长春130022)(苏州大学化学系苏州)关键词丙烯腈,配位聚合,钕配合物丙烯腈聚合通常采用BF_3、TiCl_4、过氧化苯甲酰 ̄...  相似文献   

3.
聚合物载体-稀土金属配合物的研究.聚(苯乙烯-4-乙烯基吡啶)钕配合物在丁二烯聚合中的催化行为李晓莉于广谦*李玉良(中国科学院长春应用化学研究所长春130022)关键词苯乙烯,乙烯基吡啶,共聚物,钕配合物,丁二烯聚合1996-04-11收稿,1996...  相似文献   

4.
丙烯酸酯类极性单体的聚合反应通常采用自由基型引发剂。过渡金属化合物与烷酸铝所组成的配位催化剂对这类极性单体的催化聚合迄今仍处于研究阶段。我们在稀土催化环氧烷烃聚合的基础上曾研究了稀土钕的磷酸盐体系催化甲基丙烯酸甲酯、正丁酯的聚合。本文研究了环烷酸钕体系催化丙烯酸乙酯及丙烯酸正丁酯的聚合特征。  相似文献   

5.
本文采用RP-HPLC和二极管阵列检测器建立了小蔓和大蔓长春花中长春胺的快速定性和定量测定方法。利用HPL保留时间和二级管阵列检测器给出的紫外光谱进行定性,并用半制备HPLC方法将长春胺收集纯化后用质谱和红外光谱加以确证。小蔓长春花中的长春胺含量可直接从乙醇萃取液中测定,含量超过千分之五。大蔓长春花中长春胺含量低于十万分之一须经一次制备分离后才可测定。  相似文献   

6.
李平  俞惟乐  张仁斌  周韵丽 《色谱》1990,8(3):139-142
 本文采用RP-HPLC和二极管阵列检测器建立了小蔓和大蔓长春花中长春胺的快速定性和定量测定方法。利用HPL保留时间和二级管阵列检测器给出的紫外光谱进行定性,并用半制备HPLC方法将长春胺收集纯化后用质谱和红外光谱加以确证。小蔓长春花中的长春胺含量可直接从乙醇萃取液中测定,含量超过千分之五。大蔓长春花中长春胺含量低于十万分之一须经一次制备分离后才可测定。  相似文献   

7.
Nd(naph)3-Al(i-Bu)3催化邻苯二甲酸酐与环氧丙烷交替共聚   总被引:2,自引:0,他引:2  
Nd(naph)3Al(iBu)3催化邻苯二甲酸酐与环氧丙烷交替共聚房江华黄士力(宁波师范学院化学系,宁波315020)沈之荃(浙江大学高分子科学与工程学系,杭州310027)关键词环烷酸钕,交替共聚,邻苯二甲酸酐,环氧丙烷分类号O643/TQ3...  相似文献   

8.
球笼烯(C_(60)/C_(70)载体钕系催化丁二烯聚合的研究赵春英,陈滇宝,仲崇祺,董文寰,徐玲,唐学明(青岛化工学院高分子材料系青岛266042)杨海滨,李明辉,邹广田(吉林大学超硬材料国家重点实验室长春130023)关键词球碳载体钕系催化剂,聚丁...  相似文献   

9.
球笼烯(C_(60)/C_(70)载体钕系催化丁二烯聚合的研究赵春英,陈滇宝,仲崇祺,董文寰,徐玲,唐学明(青岛化工学院高分子材料系青岛266042)杨海滨,李明辉,邹广田(吉林大学超硬材料国家重点实验室长春130023)关键词球碳载体钕系催化剂,聚丁...  相似文献   

10.
李玉良  韩冬  欧阳均 《催化学报》1986,7(3):276-282
研究了聚合物载体-钕络合物-氯代烷-三异丁基铝新体系用于共轭双烯的聚合,所用载体为苯乙烯-丙烯酸共聚物。丁二烯聚合时体系的催化活性的大小既取决于氯代烷的种类,又与配制催化剂的溶剂有关。聚合物载体-钕络合物体系的活性高于小分子异辛酸钕和环烷酸钕体系。氯代烷的种类不影响所得聚合物的微观结构。体系保持了小分子稀土催化剂所具有的良好定向效应,所得聚丁二烯的顺式-1,4结构含量高于98%。采用这一体系得到的聚异戊二烯的顺式-1,4结构含量在96%左右。载体本身的组成及其络合物中稀土的含量对体系的活性影响很大。  相似文献   

11.
微乳液电动色谱测定油-水分配系数的改进方法研究   总被引:1,自引:0,他引:1  
通过考察微乳液电动色谱(MEEKC)中化合物浓度和高电场对其迁移行为的影响, 探讨了化合物分配于微乳后改变微乳内相性质的原因, 以及电泳高电场致使微乳液性质变化的机理. 在此基础上建立了一种测定化合物油-水分配系数的改进型MEEKC方法. 将此改进方法应用于烷基苯化合物之油-水分配系数的测定, 其测定值与文献参考值平均相差0.07个对数单位, 准确度较现行MEEKC方法有了明显提高.  相似文献   

12.
A carbon supported Pd(Pd/C) catalyst used as the anodic catalyst in the direct formic acid fuel cells(DFAFC) was prepared via the improved complex reduction method with sodium ethylenediamine tetracetate(EDTA) as stabilizer and complexing agent.This method is very simple.The average size of the Pd particles in the Pd/C catalyst prepared with the improved complex reduction method is as small as about 2.1 nm and the Pd particles in the Pd/C catalyst possess an excellent uniformity.The Pd/C catalyst shows a high electrocatalytic activity and stability for the formic acid oxidation.  相似文献   

13.
The classical method for preparation of covalently boned cellulose derivative chiral stationary phases (CSP) with diisocyanate as spacer was improved. Diisocyanate was firstly allowed to react with 3-aminopropyltriethoxysilane, and the resulting product was then applied as the spacer reagent to immobilize cellulose derivatives onto silica gel. Influences of the amount and the length of the spacer on the optical resolution ability of the CSP were investigated. Comparing improved procedure to classical diisocyanate method, the cross-linking between the glucose units of the cellulose derivatives was avoided to the most extent. With the improved procedure, regio-nonselective ways could be adooted to prepare covalently bonded CSP, which showed an advantage for the rapid preparation.  相似文献   

14.
在前人工作基础上,对皮革及皮革制品中五氯苯酚残留测定方法经试验改进,增加浓硫酸净化步骤,并以艾氏剂作为标物,乙酰五氯苯酚用填充气相色谱测定。  相似文献   

15.
Mononuclear CuL and Cu(2L) complexes, where L is propyl-thiazol-2-ylmethylene-amine, covalently immobilized onto SiO2, can catalyze efficiently the oxidation of 3,5-di-t-butylcatechol (DTBC) to 3,5-di-t-butylquinone (DTBQ) by utilizing ambient O2 as oxidant. By increasing the loading of L on SiO2, the DTBQ formation can be improved up to 400% vs the homogeneous catalyst. Equally important is however that grafting per se at low loading is not adequate for an improved catalytic activity. Appropriate loadings have to be achieved, which then may result in significant catalytic performance. Based on EPR spectroscopy a theoretical method is developed, eq A12, for spin-spin distance estimation in heterogeneously dispersed surface complexes. Practical rules including error estimates are provided. By applying this method to the [SiO2-CuL] catalysts it is shown that mononuclear copper complexes fixed on SiO2 with Cu...Cu distances as short as 4.9 +/- 0.3 A are responsible for the improved catalytic activity. The present results demonstrate that mononuclear Cu complexes can have considerable catecholase activity, if the proper geometrical proximity can be fixed. Grafting on SiO2 may be an efficient method for engineering catalysts with improved performance.  相似文献   

16.
Recombinant human erythropoietin (rhuEPO) has been extensively used as a pharmaceutical product for treating anemia in the clinic. Glycosylation of rhuEPO was crucial for affecting biological activity, immunogenicity, and pharmacokinetics. Because of the heterogeneity of glycan, the structure of rhuEPO was complex with several isoforms. Characterization of isoforms was important for quality control of rhuEPO. Here, an improved cIEF method has been established and validated. A polarity-reversed focusing step was used by reversing both the polarity of the voltage and the catholyte and anolyte vials. A weak base (100 mM ammonium hydroxide solution) was used as a chemical mobilizer to make the acidic bands mobilize stably to the detection window. Compared with CZE method in European Pharmacopoeia, the numbers of isoforms and their peak area percentage were highly consistent. Better reproducibility and higher resolution have been obtained by the improved cIEF method. Moreover, in improved cIEF method, the isoelectric points (pI) of each isoform can be calculated and used for identification. It was also the first time that the cIEF method was fully validated for rhuEPO analysis according to the International Conference on Harmonization (ICH) guidelines.  相似文献   

17.
应用色谱-质谱联用仪(GC-MS)研究了裂解气中痕量NO、AsH3、COS、硫醇、硫醚、甲醇等杂质的分析方法,研究结果表明该法具有灵敏度高、选择性好的特点,可为裂解气的利用研究提供可靠的数据,经过改进后还有可能被乙烯和丙烯生产厂用作乙烯或丙烯中痕量杂质分析的常规方法。  相似文献   

18.
平台石墨炉原子吸收法直接测定高温镍基合金中硒   总被引:2,自引:0,他引:2  
姚金玉  云作敏 《分析化学》1993,21(7):846-849
研究了基体改进剂及其用量,硒的灰化、原子化和出现温度,以及近20种共存离子的干扰。采用镍和钯混合液作基体改进剂,硒的灵敏度高,抗干扰能力强,不需要分离样品基体,可以采用平台石墨炉法直接测定高温镍基合金中硒。  相似文献   

19.
成忠  诸爱士 《分析化学》2008,36(6):788-792
针对光谱数据峰宽、局部效应显著、含有噪音、变量个数多及彼此间常存在严重的复共线性等问题,改进和设计一种光谱数据局部校正方法:基于窗口平滑的段式正交信号校正方法,并将之结合偏最小二乘回归,以实现光谱数据的预处理及定量分析。通过NIPALS算法初始化将滤去的正交成分,以近邻分段方式进行逐个波长点的正交信号校正。而后将去噪后的光谱矩阵作为新的自变量阵,通过偏最小二乘回归构建其与性质参变量间的校正模型。通过小麦近红外漫反射光谱数据的应用实验结果表明,本方法正交成分估计稳定,去噪明显,模型的预报性能优于其它方法,PLS成分数减少,模型更加简洁。  相似文献   

20.
本文研究了甲基丙烯酸羟乙酯均聚和共聚制备珠体的途径及影响因素,提出了一种针对极性单体的新的悬浮聚合方法;并探讨了聚合物珠体粒度分布的影响因素。研究发现,二乙烯基苯在甲基丙烯酸羟乙酯共聚反应中的用量会影响聚合反应的成败。  相似文献   

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