ICP—AES法测定出口镁砂

应用ICP-AES法对出口镁砂中硅、钙、铁、铝、钛等氧化物含量进行测定。文中对其测试方法、条件进行探讨;辅以灼烧减量的测定,从中可以求出高含量的氧化镁。方法准确,快速,优于化学法。     

Enantiomeric separation of α-phenylethylamine and its analogs by mixed chiral and achiral stationary phase

A mixed stationary phase of modified β-cyclodextrin, 2,6-di-O-butyl-3-O-butyryl-β-cyclodextrin (phase A), and SE-54 (phase B) was used for enantiomeric separation of α-phenylethylami-ne, o,m,p-methyl and o,m,p-methoxy-substituted analogs. The composition of mixed phase was selected by comparison of each calculated amin(= (γm,i+1)/(γm,i))> the relative retention values of the most adjacent peaks, and γm,last, the relative retention values of the last eluting peak at each preselected ratio. Values of γm,i,α calculated by derived equations were in good agreement with the experimental results obtained with two specified mixed phases. All solutes investigated were almost baseline separated at a predicted composition of phase A and phase B in a single run within 18 minutes.     

Enthalpy-entropy compensation effect in gas chromatographic enantiomeric separation

In this paper, the enthalpy-entropy compensation effect in the enantiomeric separation by modified cyclodextrins (CD) and diamide chiral stationary phase (CSP) gas chromatography was investigated using the method of plotting △(△H) versus △(△G) rhm combined with t-test statistic analysis. The investigated racemates cover α-phenylethylamine and its analogs, 2-alkylamines, chiral acyclic alcohols, halogenated arylethanediol-1, 2-diperfluoropropionates, amino acid and its analogs, and two series of compounds containing chloro and bromo substituents. From the compensation analysis results, the effects of the diluent composition in the investigated chiral stationary phases, the size and the modified groups on investigated cyclodextrins, the derivatization methods and the groups attached to the stereocenters on enantiomeric separation mechanisms were all discussed.     

空间材料抗原子氧有机涂层防护作用的光谱分析

用Fourier变换红外光谱(FTIR)、光电子能谱(XPS)和扫描电镜(SEM)对在模拟原子氧(AO)环境中,空间材料及在其表面涂覆的有机防护涂层的表面所发生的侵蚀与防护作用进行了研究。结果表明：采用环氧树脂、聚胺脂、醇酸树脂作为防护涂层,经AO辐照后,它们的表面形貌均发生了较大变化,腐蚀严重;而用有机硅涂层的表面形貌变化却甚小,具有较明显的防护效果。光谱分析表明,这种防护作用缘于有机硅涂层表面经AO辐照后生成了致密的氧化硅膜层,对抑制AO的进一步侵蚀起到了抑制作用。     

TiO2-Al2O3复合氧化物负载NiMo加氢脱硫催化剂的研究

采用溶胶凝胶技术，从Al2O3载体的表面改性出发，制备了TiO2-Al2O3复合载体。采用此改性载体制备了NiMo／TiO2-Al2O3催化剂；用中压固定床微反装置考察了载体改性对制备的催化剂的噻吩加氢脱硫(HDS)活性的影响．用透射电镜、NH3-TPD及吡啶红外光谱法对改性载体和催化剂进行了表征．结果表明，经钛溶胶改性的载体制备的催化剂与原有载体制备的催化剂相比，催化剂活性提高了20％．改性载体表面负载的钛溶胶以纳米尺寸的TiO2微粒形态存在．     

Characterization and tribological investigation of self-assembled trimethoxysilyl-functionalized poly(phthalazinone ether ketone)thin films on glass substrates

<正>Trimethoxysilyl-functionalized PPEK(PKGS) films had been designed to serve as wear resistant coatings for silicon surfaces. These surface films were formed by a dip-coating technique applied to self-assembled monolayers(SAMs).The formation and wetting behavior of PKGS films were characterized by means of contact angle measurement.The friction coefficient of the film prepared is very low(about 0.1),and the anti-wear behavior is good,with a lack of failure after sliding over 1800 s.     

红外光谱分析中样品处理方法的改进

介绍了液体和固体样品的常规制样方法 ;指出了其中最常用的方法———压片法和液膜法的不足之处 ;提出了一种改进的制样方法 ,即以廉价的空白KBr压片作片基 ,通过液膜法或浸渍法制样。对于低沸点液体样品 ,以两片空白KBr压片代替晶体盐窗 ,模拟液体池窗片液膜法制样 ;对于高沸点液体样品 ,将样品用挥发性有机溶剂稀释 ,采用浸渍法制样 ,即把空白KBr压片在稀释后的溶液中浸渍后挥发掉有机溶剂制样 ;对于固体样品 ,将其溶解于挥发性有机溶剂 ,浸渍法制样。与按常规制样方法所获得的红外光谱图进行比较 ,这种改进的制样方法所得谱图 ,能达到定性分析的要求 ,且弥补了常规液膜法和压片法的不足     

光谱法研究Cu2+诱导的不同时间的LDL体外氧化

氧化低密度脂蛋白(oxidized low density lipoprotein,oxLDI)被认为是动脉硬化的关键致病因素.文章综合运用紫外吸收光谱、荧光光谱、同步荧光光谱及圆二色(circular diclaro‘lsm.CD)光谱研究了(好'诱导不同时间的U)IJ体外氧化过程.随着氧化时间的增加.生成的丙二醛(malonaldehyde,MDA)的量逐渐增加,其相对应的430 nm 处的荧光强度也随之加强,氧化过程中生成了新的氧化产物.氧化低密度脂蛋白紫外吸收增强;表征氨基酸残基信息的特征荧光强度和同步荧光强度降低;载脂蛋白B-100(apolipoproteinB-100,apoB-100)α-螺旋含量减少.实验结果表明,LDL氧化过程中Cu2+不仅诱导了氧化产物的生成,而且改变了apoB-100的构象进而导致了生色基团的微环境的变化.     

α，α′-二氧代烯酮环二硫代缩酮类化合物的谱学研究

研究了5种含有苯环取代基的α，α′—二氧代烯酮环二硫代缩酮类化合物的红外光谱的特征吸收规律，指出了这类化合物分子结构对红外吸收谱带的影响；对^1H NMR，^13C NMR共振谱带做了全面的归属。并且讨论了分子结构对^1H NMR，^13C NMR共振谱带化学位移的影响，其变化规律与红外光谱一致，为这类化合物的结构及谱学研究提供了启发性的模式。     

双圆盘加权Dirichlet空间上Toeplitz算子的约化子空间

刻画了双圆盘加权Dirichlet空间D_α(D~2)上Toeplitz算子T_Z_1N(或T_z_2N)和T_z_1N_z_2N的约化子空间.结果表明Toeplitz算子T_z_1N(或T_z_2N)的约化子空间结构与权系数α无关,而Toeplitz算子T_2_1N_z_2N的约化子空间结构与权系数α有关.