FX-100核磁共振仪频率综合器的检修

该综合器(5610A型)作为多核实验的发射源能输出2～3Vpp,0.1～160MHz不同频率的信号。频率变化由计算机控制。常见故障是无输出,或输出幅度小、使谱仪不能正常工作。上述故障多数与压控振荡器(VCO)控制电压不正常有关(它决定

钐-铽-2-噻吩甲酰三氟丙酮-氯代甲基三烷基铵-Triton X-100荧光体系的研究及其分析应用

本文研究了铽(Tb~(3-))对钐(Sm~(3-))-2-噻吩甲酰三氟丙酮(TTA)-氯代甲基三烷基铵(N_(263))-Triton X-100荧光体系的共发光效应,结果表明:Tb~(3-)的浓度1×10~(-5)～5×10~(-5)mol/L范围内体系的荧光强度最大.Sm~(3-)的浓度在1.0×10~(-9)～1.0×10~(-7)mol/L范围内与荧光强度呈线性关系,检测限为1.0X10~(-11)mol/L,方法灵敏,简便,用于混合稀土样品中痕量Sm~(3-)的测定,结果满意。

稀土离子对铕-2-噻吩甲酰三氟丙酮-氯化甲基三烷基铵-Triton X-100荧光体系的共发光能力的比较

本文研究了稀土离子对铕(Eu)-2-噻吩甲酰三氟丙酮(TTA)-氯化甲基三烷基铵(N263)-Triton X-100体系的共发光能力,提出用放大倍数作为共发光能力比较的定量标准,用能量转移效率和能量利用率来预测稀土离子的共发光能力。该方法适用于不同条件或不同体系之间共发光能力的定量比较。

钴-4-(5-氯-2-吡啶偶氮)-1,3-二氨基苯-Triton X-100体系的析相富集及痕量钴的光度测定

本文研究了TritonX-100在浊点条件下对钴-4-(5-氯-2-吡啶偶氮)-1,3-二氨基苯(5-Cl-PADAB)络合物的析相条件,在pH4.0～6.0介质中,将胶束溶液加热到92±1℃,保持40min,络合物即被TritonX-100相富集。富集液在575nm测定吸光度,钴含量在0～4μg/5ml范围内服从比尔定律,干扰离子可在TritonX-100析相液中加入H_2SO_4消除。拟定的方法灵敏、简捷,已用于不经分离直接测定人发及自来水中痕量钴。

稀土混合共发光效应的研究——(铽-钆-钇)-铕-噻吩甲酰三氟丙酮-氯化甲基三烷基铵-Triton X-100荧光体系

本文研究了铽(Tb)、钇(Y)、钆(Gd)及它们的混合物对铕(Eu)-噻吩甲酰三氟丙酮(TTA)-氯化甲基三烷基铵(N_(263))-Triton X-100体系的共发光效应,发现稀土离子混合物的共发光效应具有线性加和性,用混合共发光体系不仅能保持单个稀土离子的共发光体系的增敏性,而且抗干扰能力增强,并经过实际样品分析的验证,结果令人满意。

稀土配合物导数吸收光谱研究Ⅳ.Ln~(3+)-Ferron-Triton X-100配合物导数光谱的研究及其应用

具有f-f超灵敏跃迁的稀土配合物导数吸收光谱可大幅度提高稀土元素的测定灵敏度,钕-高铁试剂(Ferron,7碘-8羟基喹啉-5-磺酸)即为此类配合物,但其测定灵敏度提高不多。研究发现,在Ln~(3+)(Pr~(3+)、Nd~(3+)、Er~(3+))-Ferron体系中加入表面活性剂可形成新的配合物,使其f-f超灵敏跃迁吸收谱线增强,峰形显著变化,其中钕和铒的吸收峰

CYCLIC VOLTAMMETRIC STUDY ON THE TRANSFER MECHANISM OF ALKALI-METAL IONS ACROSS LIQUID LIQUID INTERFACE FACILITATED BY TRITON X-100

The transfer behavior of alkali motal ions K~+ and Na~+ across the interfaces of water/nitrobenzene and water/1, 2-dichloroethane facilitated by Triton X-100 is investigated by cyclic voltammetry with four electrodes. The equations of interfacial half-wave potential derived in terms of the mechanism proposed isverified by the experimental data and consistent with the practical △_0~wφ_p-pM curves.

Triton X-100推动碱金属离子在液/液界面上转移的机制和伏安行为

本文用四电极循环伏安法研究了非离子型表面活性剂Triton X-100推动碱金属离子K~+,Na~+等在水/硝基苯,水/1,2-二氯乙烷界面上的转移过程,根据实验结果提出Triton X-100推动金属离子转移的一种机制,推导了转移半波电位方程式,并用实验进行了验证。

Addition reactions of nitrones on the reconstructed C(100)-2 x 1 surfaces

In this paper, the reactions of nitrone, N-methyl nitrone, N-phenyl nitrone and their hydroxylamine tautomers (vinyl-hydroxylamine, N-methyl-vinyl-hydroxylamine and N-phenyl-vinyl-hydroxylamine) on the reconstructed C(100)-2 x 1 surface have been investigated using hybrid density functional theory (B3LYP), Moller-Plesset second-order perturbation (MP2) and multi-configuration complete-active-space self-consistent-field (CASSCF) methods. The calculations showed that all the nitrones can react with the surface "dimer" via facile 1.3-dipolar cycloaddition with small activation barriers (less than 12.0 kJ/mol at B3LYP/6-31g(d) level). The [2+2] cycloaddition of hydroxylamine tautomers on the C(100) surface follows a diradical mechanism. Hydroxylamine tautomers first form diradical intermediates with the reconstructed C(I 00)-2 x I surface by overcoming a large activation barrier of 50-60 kJ/mol (B3LYP), then generate [2+2] cycloaddition products via diradical transition states with negligible activation barriers. The surface reactions result in hydroxyl or amino-terminated diamond surfaces, which offers new opportunity for further modifications. (C) 2007 Elsevier B.V. All rights reserved.

Addition reaction of nitrones on the reconstructed Si(100)-2 x 1 surface

The reaction of nitrone, N-methyl nitrone, and their hydroxylamine tautomers (vinyl-hydroxylamine and N-methyl vinyl-hydroxylamine) on the reconstructed Si(100)-2 x 1 surface has been investigated by means of hybrid density functional theory (B3LYP) and Moller-Plesset second-order perturbation (MP2) methods. The calculations predicted that both of the nitrones should react with the surface dimer via facile concerted 1,3-dipolar cycloaddition leading to 5-member-ring compounds. The reaction of hydroxylamine tautomers on the Si(100) surface follows pi-complex (intermediate) mechanism. For the reaction of N-methyl vinyl-hydroxylamine, the pi-complex intermediate undergoes [2+2] cycloaddition leading to a 4-member-ring compound. But in the reaction of vinyl-hydroxylamine, the intermediate undergoes H-migration reaction ("ene" reaction) resulting in the oxime-terminated Si surface. All the surface reactions result in the hydroxyl-terminated silicon surfaces, which are very useful for the further modification of the semiconductor.

100块南极格罗夫山陨石的类型划分及其岩石学特征

根据岩石矿物学研究，包括岩石结构、橄榄石的Fa值和低钙辉石的Fs值以及金属模式含量等，100块格罗夫山陨石分别被划分为：4块H3型、11块H4型（其中一块为H4-an）、10块H5型、3块H6型、2块L3型、6块L4型、31块15型、32块L6型和1块LL4型。格罗夫山普通球粒陨石在类型分布上，其比例和南极以及非南极普通球粒陨石有显著不同，说明可能存在相当数量的成对陨石。分类陨石样品比较新鲜，其中98块陨石的风化程度为W1，仅有2块陨石风化程度分别为W2和W3。另外，这些陨石中冲击程度较高的样品占有一定比例，它们是研究冲击作用的理想样品。