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181.
低镍甲烷化催化剂中镍和氧化镧的分散研究   总被引:4,自引:0,他引:4  
本文用X射线衍射法(XRD), 透射电镜(TEM), 配合电子衍射对Ni/Al2O3,Ni/γ-Al_2O_3-La_2O_3等催化剂中镍晶粒度和La_2O_3的分散状态进行了测量和讨论。用透射电镜测量了不同La_2O_3含量的催化剂中镍晶粒度分布, 其平均直径可与X射线宽化法测定值相比较。催化剂中随La_2O_3加入量的增加, Ni晶粒有细化趋势, 从而提高了甲烷化催化活性。对La_2O_3在γ-Al_2O_3表面作密置单层分散的模型提出了新的旁证, 并推断由于La_2O_3在γ-Al_2O_3表面高分散并产生较强相互作用, 使γ-Al_2O_3接近表层晶格发生畸变。  相似文献   
182.
Surfactant molecules containing hydrophobic long alkyl chains and hydrophilic groups can organize into various micellar structures both in bulk solution and at interface. However, because of the dynamical nature of surfactant micelles, efforts directed at fixing their structures in bulk solution by polymerization have met with limited success. Herein, we report a unique and simple method of stabilizing surface micelles of a low molecular weight surfactant 11-acryloyloxyundecyltriethylammonium bromide (AUTEAB) through in situ intramicellar polymerization on the mica surface. Atomic force microscopy (AFM) observations show that the cylindrical micellar structure formed by AUTEAB monomers at the mica/water interface is preserved after the in situ polymerization, and the stability of the polymerized surface micelles is greatly enhanced compared with that of the unpolymerized ones.  相似文献   
183.
稀土氨基酸固体络合物的合成及结构分析进展   总被引:16,自引:2,他引:16  
马爱增  李来明 《分析化学》1993,21(1):105-111
本文综述了稀土氨基酸络合物的合成,以及应用红外、核磁、X-射线衍射、热分析等方法进行结构分析研究的进展情况。  相似文献   
184.
The inhibition of lingninase by hydrogen peroxide in the presence of cationic surfactant CTAB was studied by kinetic speetrophotometdc technique. Results showed that addition of CTAB enhanced the inhibition by H202, but it did not alter the inhibition pattern and the inhibition constant changed little with theco-ncentration of CTAB. Modification of the enzymic protein by the surfactant monomer may be responsible for the above mentioned results.  相似文献   
185.
运用广义梯度密度泛函理论(Generalized Gradient Approximation,GGA)的PBE(Perdew-Burke-Ernzerh)方法结合周期性平板模型,研究了氯气分子和氯原子在CuCl(111)表面上的吸附。通过对不同吸附位和不同单层覆盖度下的吸附能和几何构型参数的计算和比较发现:氯气分子在CuCl(111)表面的吸附为解离吸附;单层覆盖度为0.50时的吸附构型为稳定的吸附构型;氯气分子平行吸附在CuCl(111)表面时最稳定,吸附能最大,达364.5 kJ·mol-1;伸缩振动频率的计算结果表明,吸附后的氯气分子的伸缩振动频率与自由氯气分子的伸缩振动频率相比,都发生了红移;布居分析结果表明整个吸附体系发生了由Cu原子向氯气分子的电荷转移。氯原子吸附的计算结果显示氯原子以穴位稳定的吸附在CuCl(111)表面。  相似文献   
186.
Electrogenerated chemiluminescences (ECLs) based on tris(2,2′-bipyridine)ruthenium(II) (Ru(bpy)32+) and lupin alkaloids, for instance, sophoridine (SRI), matrine (MT), sophoranol (SR) and sophocarpine (SC) in an aqueous alkaline buffer solution (pH 9.0) are studied. The light emission is mainly caused by an electro-oxidation reaction between tertiary amino group on the alkaloid compounds and Ru(bpy)32+ in a thin layer flow cell equipped with a glassy carbon disc electrode (22.1 mm2) at the potential of +1.50 V (versus Ag/AgCl). The luminescence wavelength of 610 nm confirmed that ECL is caused by Ru(bpy)32+∗ to its ground state. ECL intensities of these lupin alkaloids are affected by the substituent character, three-dimensional conformation of hydrogen on β-carbon atom. Ionization potentials taken from calculation data further confirm the experimental results. In addition, the factors affecting the determination and HPLC separation of the four alkaloids are also investigated.  相似文献   
187.
High molecular weight copoly(ether ketone)s (PEK) based on 4-(4-hydroxyphenyl)-1-phthalazinone (DHPZ)/4,4′-thiobisphenol (TBP)/4,4′-diflourodiphenylketone (DFK) were prepared by nucleophilic substitution polycondensation. The copolymers were characterized by FT- and ^1H-NMR. Thermal properties and solubility of copolymers were studied.  相似文献   
188.
以戊二醛为交联剂,制备了壳聚糖(CS)-羧甲基纤维素(CMC)聚合物电解质膜.用电子显微镜观察其表面形貌.IR分析表明该聚合物薄膜含有COOH,NH 3官能团,具有两性离子的特征.与CS膜或CMC膜相比,该膜能稳定存在于酸碱溶液中.膜特性研究表明CS-CMC聚合物电解质膜具有离子交换和选择性渗透能力,可作为隔膜电解制备高铁酸盐.  相似文献   
189.
190.
A simple, novel, specific, rapid and reproducible ultra‐performance liquid chromatography electrospray ionization tandem mass spectrometry method has been developed and validated for the determination of hydroxysafflor yellow A (HSYA) in biological fluids (plasma, urine and cerebrospinal fluid) of patients with traumatic brain injury after intravenous injection of Xuebijing (XBJ). Liquid–liquid extraction was performed, and separation was carried out on an Acquity UPLC? BEH C18 column, with gradient elution using a mobile phase composed of methanol and 0.1% formic acid at a flow rate of 0.3 mL/min. A triple quadrupole tandem mass spectrometer with electrospray ionization was used for the detection of HSYA. The mass transition followed was m/z 611.0 → 491. The retention time was less than 3.0 min. The calibration curve was linear in the concentration range from 2 to 6125 ng/mL for cerebrospinal fluid, plasma and urine. The intra‐ and inter‐day precisions were <10%, and the relative standard deviation of recovery was <15% for HSYA in biological matrices. The method was successfully applied for the first time to quantify HSYA in the biological fluids (especially in cerebrospinal fluid) of patients with traumatic brain injury following intravenous administration of XBJ. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
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