化学法镁钛系高效载体催化剂多活性中心的DSC证据

用高效载体钛催化剂进行乙丙共聚物的合成,已有大量报道,但从聚合产物热分析出发对其催化活性中心的性质进行探讨,报道尚少。我们用化学反应法制备的高效载体钛催化剂进行乙丙共聚反应,所得产物进行热分析结果表明,共聚产物具有很宽的链段序列分布,呈现出吸热双峰模式,与催化体系及其聚合过程ESR分析,共聚物溶剂萃取及其~(13)C-NMR分析结果一起,有力地支持催化体系多活性中心的结论。

Li/La_2O_3的表面活性氧及其在甲烷氧化偶联中的催化行为

甲烷氧化偶联反应近年来研究十分活跃。Lunsford等报道了载有碱金属的碱土氧化物是对此反应有效的催化剂,并提出晶格取代型活性中心[M~+O~-〕和表面活化、气相偶联的反应机理。Otsuka等系统地研究了稀土氧化物的甲烷氧化偶联活性,本文通过氧化镧中添加锂前后的对比,运用骤冷技术与ESR法研究了催化剂的表面活性氧,以低温TPD法研究了甲烷在催化剂表面上的吸附与活化,以及在甲烷氧化偶联中的催化行为。

叶绿素a光诱导产生O_2~/OH氧自由基

将ESR自旋捕俘技术应用于氧的瞬时自由基测定,为叶绿素a Chα光诱导化学行为的研究,提供了更为有力的手段。Harbour和Bolton用自旋捕俘剂DMPO(5,5-Dimethyl-1-pyrroline-N-oxide)首次证明,在光照下叶绿体可产生O_2。他们又用DMPO证明,Chla于光照下有少量OH自由基产生。继而Van Ginkel于1980年报导用分离出来的

Keggin结构钼系杂多蓝的离析和性质研究

本文报道了八种1:12系列钼系杂多蓝KyHzXMo_(12)O_(40)·nHp(X=Si,P,As,Ge)的制备和离析方法,并通过元素分析、电位滴定、极谱、循环伏安、红外光谱、可见-紫外光谱、X射线粉末衍射、XPS和~(31)PNMR对产物进行了表征。测定了四电子钼硅杂多蓝的单晶结构,确定了还原钼原子的位置是第三位、七位、八位、十位。实验结果表明,杂多蓝仍基本保持了Keggin结构。首次系统研究了八种杂多蓝固体的ESR谱,发现二电子、四电子杂多蓝比一电子杂多蓝具有更小的电子离域程度;热性质研究表明,固体杂多蓝随还原程度增大,热稳定性增强;研究其氧化还原性质发现,在不同介质中,杂多蓝的氧化序发生变化,极谱半波电位与杂原子电负性线性相关。并发现P和As的杂多蓝具有极强的抗酸解能力。

Sn-Mo混合氧化物的缺陷结构及催化性能的研究

本文以1-丁烯在水蒸汽存在下选择性氧化制甲乙酮为典型反应,利用 XRD,ESR,IR,XPS,TEM 和 SEM 研究了 Sn-Mo 氧化物的结构与活性的关系.制备了8个样品,A,B,C,D,E,F,G 和 H 的 Mo/(Mo+Sn)分别为0,0.1,0.2,0.4,0.6,0.8,0.9,1.0.根据结构特征,可将 Sn-Mo 氧化物分为三组:第Ⅰ组 Mo/(Mo+Sn)≤0.2;第Ⅱ组0.2

甲醇氨氧化制氢氰酸的铁钼催化剂活性组分的研究

采用X射线衍射、IR、M(?)ssbauer、ESR和ESCA等方法研究了甲醇氨氧化制氢氰酸的铁钼催化剂活性组分与催化活性的关系.X射线衍射和IR研究指出,催化剂中的铁和钼是以Fe_2(MoO_4)_3、MoO_3和a-Fe_2O_3存在.Fe_2(MoO_4)_3的相对含量与活性随Fe/Mo的变化呈峰形对应关系.M(?)ssbauer、ESR和ESCA分析表明,铁是以Fe~(3+)存在,但有两种配位,一种是Fe_2(MoO_4)_3中的八面体配位,另一种可能是Fe_2O_3·xMoO_3(x<3)的不完善配位.前者是基本活性组分,和后者一起完成选择氧化的功能.

乙烯基三甲基硅烷等离子体聚合物膜的结构与性能

采用外部电极电容耦合高频等离子体装置对乙烯基三甲基硅烷(VTMS)进行等离子体聚合。用IR、XPS、PGC/MS、X-ray、ESR和元素分析等方法对聚合物结构进行表征,并推断聚合反应历程。应用TG研究聚合物的热性能。通过X-ray证实聚合物为非晶结构。在无添加气体存在时聚合,XPS测试结果表明产物中有氧嵌入,且聚合物的C/Si比总的说来比单体的C/Si比低。TG的测试结果表明聚合物膜具有优良的热稳定性。

聚N-甲基苯胺的质子酸掺杂

聚N-甲基苯胺(PMAn)可用酸碱进行可逆的掺杂及反掺杂。掺杂使电导增大。掺杂过程在本质上是链的质子化过程,与阴离子无关。用FTIR、UV-VIS、ESR表征了掺杂前后结构的变化。结果表明,掺杂后链上来偶电子增加,电子及电荷更加离域化,并与电导率增大相吻合。PMAn的导电载流子可能是离域化的阳离子自由基。

ZrO_2-Y_2O_3:Ce,Fe,Co晶体的发光光谱和电子顺磁共振

本文详细解释先前测量的(YSZ)ZrO_2-Y_2O_3(88:12):CeO_2(0.01,0.3,0.5wt%),Fe:O:0.03wt%+CeO_20.01wt%,CoO(0.1,0.3wt%)晶体γ辐照前后的吸收光谱。以250—310nm激发,测量这些晶体的发光光谱,定性研究不同浓度铈、钻杂质对YSZ色心发光的影响。YSZ在400—600nm色心发光因受到铈、钴杂质再吸收,使它的发光强度减弱。这种现象在γ辐照后变得更为明显。为了证实掺杂YSZ缺陷结构存在和杂质离子价态,测量了这些晶体辐照前后的电子顺磁共振。由单电荷(Y_((zr),V_n)′自由自旋和Fe~(3+)离子的ESR信号变化,反推铈、钻杂质在YSZ晶体中的价态变化。并和吸收光谱加以比较。

结晶聚合物的辐照效应——Ⅰ.尼龙-1010的聚集态结构对其辐射化学反应的影响

本文用DSC,WAXD,ESR和介电谱以及凝胶分数测定等技术,研究Nylon-1010的聚集态对γ-辐射化学反应以及辐照后热处理结果的影响。结果表明,辐照Nylon-1010的交联与裂解反应主要发生在非晶区或结晶表面,进一步证明了非晶区也是辐射后交联和后裂解主要反应区。

光透薄层光谱电化学法研究灿烂甲酚兰的电极过程

在铂网光透电极上,采用紫外-可见和电子顺磁共振(ESR)技术研究了灿烂甲酚兰(BCB)的电极过程。测定了BCB的标准式电极电位和电子转移数。结果表明,BCB在铂电极上进行可逆的单电子转移反应,并且氧化态和还原态均较强烈地吸附在铂电极上。ESR波谱的现场监测直接确证了单电子转移过程,并首次发现BCB的氧化态在正电位激发下呈三线态,还原态具有单电子自由基。另外对BCB的电极过程机理进行了初步探讨。

聚苯胺导电机理的探讨

本文根据ESR及宽线~1H-NMR的实验结果,对聚苯胺(PAn)导电机理作了初步探讨。结果表明,醌二亚胺与苯二胺双自由基间存在着共振关系,二者总是以一定的比例共存:掺杂时,共振平衡向苯二胺双自由基方向偏移;在频率高于50MHz时,一维的电子运动为占优势的传递方式,这种电子的传递通过Heisenberg交换来实现;当频率低于50MHz时,三维的电子扩散在导电机制中起了重要作用。

库车坳陷-南天山盆山系统第三纪脆性构造研究

Study on the structural coupling relationship between basin and range is not only helpful to recognize the basin formation and evolution systematically, but also to guide petroleum exploration in the basin. As a late Paleozoic Orogen, the South Tianshan Mountains reactivated and uplifted rapidly during the Cenozoic, and led to the Mesozoic-Cenozoic considerable thick deposits in the Kuqa Depression. The researches of the dissertation were carried out in the Kuqa depression-South Tianshan M ountain s ystem, a nd t he b rittle m icrotectonics w. ere c hosen as t he m ost important object. Based on observations and measurements of the field, we made detailed investigations on the geometry and kinematics of this area, and analyzed the abutting and cutting relationships and relative sequence of many brittle structures, such as joint, shear fractures, faults and some small-scale structures related to them closely. According to those brittle fractures' relationships with stress, the nature and variation of regional palaeostress field during the Cenozoic were studied through inversion of fault slip data and inferring stress state from joint sequences. And the deformation time was estimated primarily via ESR dating of faulting. Results show that the stress field varies as well in times as in space. The maximal principal stress direction shifted from the vertical to the horizontal, and stress regime from weak extension to strong compression from the Paleogene to the Neogene regionally. During the late Neogene, the structural deformation of the South Tianshan and the basin-range boundary was dominated by near N-S extension, while near N-S compressive deformation in the interior of the Kuqa Depression. There exits obvious differential stress state from the north to the south. ESR dating of the faulting during the Cenozoic indicates that, the normal faulting in the north edge of the Kuqa Depression have been active all along from the Miocene to the early Pleistocene, but the thrusting and reverse faulting in the interior only been active from the Pliocene to the early Pleistocene. On the base of those geological data and some geophysical information and theoretical calculation results, we infer that, the different stress regime the basin-range system is ascribed to the vertical uplift of the Tianshan Mountain. It was the vertical uplift that lead to the gravity-driven gliding of thick layers lying on the faulted basement from the South Tianshan Mountain to the Kuqa depression, and to folding and thrusting in the interior and frontal of the Kuqa depression. Combining the structural evolution with petroleum geological conditions of the Kuqa Depression, we think that the strong compressive deformation of the Kuqa Depression during rapid uplifting of the Tianshan Mountains from the Pliocene to the early Pleistocene play crucial role in the structural trap formation and proliferous gas accumulation.

现代分析技术在土壤腐殖质研究中的应用

土壤腐殖质的研究已成为土壤学、环境化学和地球化学等的热点方向之一。应用核磁共振兴谱（NMR）、红外光谱（IR）、荧光光谱（FS）、电子自旋共振谱（ESR）等现代分析技术，对在土壤腐殖质组成和结构研究中取得的主要成果进行了综述。

Synthesis and characterization of manganese-modified MCM-41

Manganese-modified mesoporous MCM-41 molecular sieves were synthesized at the absence of alkaline metal ions under mild alkaline condition using cetylpyridinium bromide surfactant as a template, and characterized with X-ray diffraction, N-2 adsorption, transmission electron microscopy, electron spin resonance (ESR), and nuclear magnetic resonance (NMR) spectroscopies. The synthesized MnMCM-41 has a high pore volume of 1.30 cm(3) g(-1) with a corresponding surface area of 1510 m(2) g(-1). The ESR and Si-29 MAS NMR spectra revealed the presence of framework manganese ions in either the as-synthesized or calcined forms. (C) 2002 Elsevier Science B.V. All rights reserved.