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971.
采用密度分离、脱灰处理和逐级化学提取等间接方法,考察了铁岭煤中Pb, Cr, Co, Ni, V五个重金属元素的宏观结合形态,并在Φ25mm小型石英流化床反应装置上考察了上述五个重金属元素在热解过程中的挥发行为。研究发现,铁岭煤中Pb, Cr, Co, Ni, V均主要与非黄铁矿类矿物质相伴生, 且高达40%~60%赋存在硅酸盐类矿物质中。Pb的碳酸盐结合态和有机束缚的离子可交换态600℃前即可分解转化,而其硫化物和硫酸盐结合态在较高的热解温度下才能分解挥发;Co、Ni的硫化物和硫酸盐结合态在高温下可部分转换为有机结合的离子可交换态;而Cr、V的硫化物和硫酸盐结合态在高温下部分转化生成了新的热稳定相。在500℃~900℃范围内,Pb属半挥发性元素,Cr, Co, Ni, V属难挥发性元素。微量元素的挥发性极大地受其伴生环境、共存活泼元素等的影响,硅铝酸盐类矿物质对重金属元素的挥发有一定的抑制作用。  相似文献   
972.
A new phosphorylcholine, (6-hydroxy) hexyl-2-(trimethylammonio) ethyl phosphate (HTEP), was synthesized andcharasterized. Segmented polyurethane (SPU) containing phosphorylcholine structure was synthesized based ondiphenylmethane diisocyanate (MDI), soft segment polytetramethylene glycol (PTMG) and HTEP, with 1,4-butanediol (BD)as a chain extender. The existence of phosphorylcholine structure on the surface of SPU was revealed by attenuated totalreflectance Fourier transform infrard spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and water contactangle measurements. The blood compatibilities of the polymers were evaluated by hemolytic testing and a platelet-richplasma (PRP) adhesion experiment, which was viewed by scanning electron microscopy (SEM) with polyurethane as areference. The novel segmented polyurethane containing phosphorylcholine structure showed improved blood compatibility.  相似文献   
973.
本文考察外加盐浓度、反离字半径和价数对6, 10Br大分子形态的影响。计算表征分子尺寸的各种参数。表明6, 10Br分子形态的转变是主链上正氮离子的静电斥力和—CH_3之间亲合力协同作用的结果。对大分子卷曲的影响是: I~->Br~->Cl~-。在KI溶液中, 6, 10Br转变为6, 10I而导致沉淀, 估计与I~-的极化率大易变形有关, 也与6, 10Br主链的结构特点有关。多价反离子(SO~(2-)_4, PO~(3-)_4)对大分子形态的影响与Cl~-和Br~-没有明显不同。  相似文献   
974.
本文以呋喃甲酸甲酯为原料, 经羟烷基化反应, 醇解反应和O-甲基化反应合成(±)-金锦香酸二甲酯甲醚。同时, 还发现了制备2-乙烯基呋喃衍生物的新方法。  相似文献   
975.
用CoMFA和HQSAR两种QSAR方法研究了50个乙内酰脲类分子的定量构效关系.本研究从构象搜索所得的低能结构出发构建化合物分子的构象, 建立CoMFA模型,并进行了全空间搜索. HQSAR本质上是一种二维的QSAR方法,与CoMFA方法相比,该方法在数据处理方面,比CoMFA方法快捷,并且可重复性好.两种方法均得到了较好分析结果, CoMFA的交叉验证相关系数q2 值为0.815, HQSAR的q2值为0.893.这些方程有力地说明了该类分子在(R,R)-N-3,5-dinitrobenzoyl-1,2-diamine型手性固定相上拆分过程中的影响因素,对今后类似拆分的实验研究提供了理论支持.  相似文献   
976.
Zhang S  Huang F  Cao X  Yang P  Zhang W  Jin L 《The Analyst》2002,127(4):485-489
Microdialysis sampling coupled with liquid chromatography-electrochemical detection (LC-ED) was developed and applied to determine the interaction of thiopurine (TP) with bovine serum albumin (BSA). A nickel hexacyanoferrate (NiHCNFe) modified electrode was fabricated and used as the working electrode in LC-ED for the determination of TP. Cyclic voltammetric experiments demonstrate that this chemically modified electrode (CME) can effectively catalyze the electrooxidation of TP. The mechanism of the catalytic oxidation of TP at the CME involves an 'EC' process. In the LC-ED, the CME also shows good stability and reproducibility for the determination of TP. The limit of detection is 5.0 x 10(-7) mol l(-1) for 6-TP with a signal-to-noise ratio of 3. The utility of microdialysis as a quantitative sampling technique for in vitro studies of drug-protein interactions was studied. The microdialysis experiments were performed in phosphate buffer solution (pH 7.4) containing different molar ratios of the drug and protein at 37 degrees C. The collected microdialysis sample with unbound TP was analyzed at the NiHCNFe CME in the LC-ED. The relative recovery of TP determined in vitro is 18.3% at a perfusion rate of 1.0 microl min(-1) and the RSD is about 2.1%. The association constant and the number of binding sites on a BSA molecule calculated with the Scatchard equation are 3.72 x 10(-3) (1 mol(-1)) and 1.51, respectively. This method provides a fast, sensitive and simple technique for the study of drug-protein interactions.  相似文献   
977.
在密度泛函理论的框架下, 采用嵌入点电荷簇模型研究了O2在MgO(001)完整和缺陷表面上的吸附.用电荷自洽的方法确定了点电荷的值.计算结果表明, O2倾向吸附在低配位的角Mg2+端.并且发现, 当O2为平躺吸附时,键长有较大的拉伸,将有利于O2的解离.同时,分别计算了使用裸簇和嵌入表观±2.0 e点电荷簇模型时的吸附能,并与采用电荷自洽方法的计算值进行了比较.结果表明,电荷自洽方法更能有效反映簇周围的环境,得到的计算结果能够较好地与实验值吻合.最后,分别计算了不同吸附情况下O2的振动频率.  相似文献   
978.
The molecular structure of trichloronitromethane has been studied in the gas phase using electron diffraction data. The molecules are found to undergo low barrier rotation about the CN bond with a planar CNO2 moiety in agreement with HF/MP2/B3LYP/6-311G(d,p) calculations. The experimental data are consistent with a dynamic model using a potential function for the torsion of V = (V6/2)(1 − cos 6τ). The major geometrical parameters (rg and ) for the eclipsed form, obtained from least squares analysis of the data are as follows: r(NO3) = r(NO4) = 1.213(2) Å, r(CN) = 1.592(6) Å, r(CCl)av = 1.749(1) Å, Cl5CN/Cl6CN = 109. 6°/106.3°(2), O3NC/O4NC = 117. 6°/114.1°(4), τCl5C1N2O3 = 0.0°, and V6 = 0.20(25) kcal/mol.  相似文献   
979.
Reaction of PdCl2(CH3CN)2 with the sodium salt of 5‐mercapto‐1‐methyltetrazole (MetzSNa) in methanol solution affords an interesting dinuclear palladium complex [Pd2(MetzS)4 ] ( 1 ). However, treatment of PdCl2(CH3CN)2 with neutral MetzSH ligand in methanol solution produces a mononuclear palladium complex [Pd(MetzSH)4]Cl2 ( 2 ). Both complexes were characterized by IR, 1HNMR, UV‐Vis spectroscopy as well as X‐ray crystallography. Single‐crystal X‐ray diffraction analyses of two complexes lead to the elucidation of the structures and show that 1 possesses an asymmetric structure: one Pd atom is tetracoordinated by three sulfur atoms and one nitrogen atom to form PdS3N coordination sphere, the other Pd atom is tetracoordinated by three nitrogen atoms and one sulfur atom to form PdSN3 coordination sphere. The molecules of 1 are associated to 1‐D infinite linear chain by weak intermolecular Pd···S contacts in the crystal lattice. In 2 , the Pd atom lies on an inversion center and has a square‐planar coordination involving the S atoms from four MetzSH ligands. The two chloride ions are not involved in coordination, but are engaged in hydrogen bonding.  相似文献   
980.
Surface immobilization provides a useful platform for biosensing, drug screening, tissue engineering and other chemical and biological applications. However, some of the used reactions are inefficient and/or complicated, limiting their applications in immobilization. Herein, we use a spontaneous and catalyst-free amino-yne click bioconjugation to generate activated ethynyl group functionalized surfaces for fast immobilization of native proteins and cells. Biomolecules, such as bovine serum albumin (BSA), human IgG and a peptide of C(RGDfK), could be covalently immobilized on the surfaces in as short as 30 min. Notably, the bioactivity of the anchored biomolecules remains intact, which is verified by efficiently capturing target antibodies and cells from the bulk solutions. This strategy represents an alternative for highly efficient surface biofunctionalization.

Fast surface immobilization of native bioconjugates through a spontaneous amino-yne click reaction is realized.  相似文献   
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