直接甲醇燃料电池三元催化剂PtRuCo/C的制备及其电化学性质

使用柠檬酸三钠作为稳定剂,硼氢化钠作为还原剂,用浸渍还原法制备了20%(w)Pt60Ru30Co10/C催化剂.利用透射电子显微镜(TEM)和X射线衍射(XRD)对催化剂进行了表征.考察了不同pH值对制备催化剂的催化甲醇氧化能力及稳定性的影响,并使用预吸附单层CO溶出方法研究了其抗中毒能力.结果表明,当pH=8时,制备的PtRuCo/C对甲醇氧化具有最高的催化活性,其催化活性远高于商业化的Pt50Ru50/C,同时催化剂的稳定性最好,高于商业化的Pt50Ru50/C的稳定性,而且预吸附单层CO的起始氧化电位比Pt50Ru50/C的明显负移.     

中波红外微型静态傅里叶变换光谱仪的设计与分析

提出一种基于微光学元件的空间调制微型傅里叶变换红外光谱仪,通过引入红外微结构衍射光学元件、多级微反射镜和微透镜阵列,实现仪器的微型化.介绍了微型傅里叶变换红外光谱仪的结构及基本原理,分析了微型准直系统和聚焦耦合光学系统的设计理论,研究了单片折衍混合准直透镜的残存像差、衍射面的衍射效率、多级微反射镜的衍射、微透镜阵列的孔径衍射和中继系统的轴向装配误差对光谱复原的影响.最后,对中波红外微型傅里叶变换光谱仪进行了建模仿真,得到的复原光谱与理想的光谱曲线比较符合,实际的光谱复原误差为2.89%.该中波红外微型静态傅里叶变换光谱仪无可动部件,且采用了微光学元件取代了传统的红外镜头,不仅稳定性良好,而且体积小、重量轻,有利于在线监测应用.     

Studies on coordination and hydrogen bond intermolecular interaction using 1D & 2D FTIR spectroscopy

Two-dimensional (2D) correlation spectroscopy is a powerful method to study the intermolecular interactions between different molecules/functional groups. In the present paper, variable concentrations were selected to construct 2D synchronous spectrum for studying the weak intermolecular interactions in solutions. Mathematical analysis performed on 2D synchronous spectra using variable concentration as an external perturbation shows that the "Orthogonal Sample Design Scheme" is necessary for eliminating the interfering cross peaks in 2D synchronous spectra. The authors prepared four mixed-solutes-solutions whose concentration series satisfy the "Orthogonal Sample Design Scheme" for each chemical system and the consequent 2D synchronous spectrum was calculated from the corresponding four 1D spectra. Thus, by 1D & 2D FTIR spectra together with solid grinding reaction, the intermolecular interactions in two chemical systems (Sodium 2-Aminobenzoate/NdCl3 in aqueous solution, and 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester (PC88A)/Naphthenic Acid (NA) in heptane solution) were studied, where the intermolecular interactions only induce subtle spectral variations in conventional 1D spectra. First, the cross peaks between f-f transition bands of Nd3+ ion at 521, 574, 741, 795 and 865 nm and pi-pi transition band of Sodium 2-Aminobenzoate at 308 nm in 2D synchronous spectrum confirm the coordination interaction between Sodium 2-Aminobenzoate and Nd3+. Solid grinding reaction between Sodium 2-Aminobenzoate and NdCl3 and FTIR spectra of the product indicate that the vibration bands of amino, carboxyl groups from sodium 2-aminobenzoate show considerable changes. Based on the spectral result above, a conclusion is drawn that Nd3+ can coordinate with Sodium 2-Aminobenzoate by amino and carboxyl groups. Second, the cross peaks between POH stretching band of PC88A at 983 cm(-1) and COOH stretching band of NA at 1 710 cm(-1) in 2D spectra confirm the interaction between PC88A and NA. Subtraction spectrum demonstrates that when PC88A is mixed with NA in heptane solution, and P=O stretching band of PC88A shifts from 1 199 to 1161 cm(-1), and POH stretching band shifts from 983 to 965 cm(-1). Based on the spectral result above, a conclusion was made that PC88A and NA can interact with each other by forming new assemblies with POH and COOH groups.     

X射线荧光光谱-玻璃熔融制样法分析铁矿中主成分和微量成分

采用ｎ样品：ｍ熔剂为１∶２的低稀释比玻璃熔融技术、Ｘ射线荧光法测定铁矿中的主成分和微量成分、既提高了灵敏度又消除了不均质效应,与粉末压片方法相比,对硫的分析得到了更好的结果。使用基本参数程序建立了一新的校正方法来校正由于烧失量、烧增量、稀释比或熔剂挥发而导致的分析误差     

High pressure synthesis and characterization of the pyrochlore Dy_2Pt_2O_7:A new spin ice material

The cubic pyrochlore Dy2Pt2O7 was synthesized under 4 GPa and 1000℃ and its magnetic and thermodynamic properties were characterized by DC and AC magnetic susceptibility and specific heat down to 0.1 K.We found that Dy2Pt2O7 does not form long-range magnetic order,but displays characteristics of canonical spin ice such as Dy2Pt2O7,including(1)a large effective moment 9.64μB close to the theoretical value and a small positive Curie-Weiss temperatureθCW=+0.77 K signaling a dominant ferromagnetic interaction among the Ising spins;(2)a saturation moment ~4.5μB being half of the total moment due to the local<111>Ising anisotropy;(3)thermally activated spin relaxation behaviors in the low(~1 K)and high(~20 K)temperature regions with different energy barriers and characteristic relaxation time;and most importantly,(4)the presence of a residual entropy close to Pauling’s estimation for water ice.     

Function-Oriented Natural Product Synthesis

Natural products and their derivatives have long been used as medicinal agents,and they still make up a significant fraction of clinically approved drugs.Natura...     

氰化金浸取液萃取机理研究

本文利用Fourier变换红外光谱 (FTIR)、放射性同位素示踪、激光光散射的实验等方法研究了有机相的溶液结构 ,初步提出季胺盐萃取金有机相中氰化金阴离子参与形成超分子结构 ,并且随着有机相中金浓度的增加 ,萃合物形成聚集体     

空间调制傅里叶变换光谱仪分束器色散特性研究

在基于多级微反射镜的傅里叶变换光谱仪中,由于分束器的色散特性, 不同波长的干涉图具有不同的横向偏移量,其在横向空间会发生混叠. 同时,不同波长的干涉图还具有不同的光程差偏移量,使其在纵向空间也会发生混叠. 根据几何光学原理,干涉图的横向混叠会减小干涉图元的有效面积. 计算表明,本研究中干涉图元的横向混叠面积为总面积的3.4%, 通过数据处理扣除混叠部分可以消除横向混叠的影响. 干涉图的纵向混叠会产生一个附加的相位延迟,削弱谱线的强度. 经分析,附加相位延迟与分束器和补偿板之间的厚度差成正比. 本文给出了发生对比度反转时分束器与补偿板厚度差的极限值, 并利用解线性方程组的方法对纵向混叠的干涉图进行了校正, 反演出的光谱与理想光谱的标准偏差仅为1.76×10^-14.     

成型压力对CrO2低温输运性质的影响

本文研究了压力对CrO2样品低温磁输运性质的影响.样品的X射线衍射结果表明(110)峰的相对强度随压力的增加而增大,说明压力对CrO2针状纳米颗粒有取向的作用.低温时CrO2样品的电阻和磁阻均随压力的增加而减少.实验结果表明,低温下样品的电导呈现出典型的晶粒间隧穿特征,其△值随着压力和磁场的增加而减小,并且△随磁场的变化幅度与成型压力有关,成型压力越高,△随磁场的变化越小.这些变化可以归因为压力对晶粒间隧穿势垒的调制.     

纳米CT成像表征锦纶6中TiO2颗粒分布状况

无机纳米材料与高分子基质共混构成有机-无机复合材料,对其电学、光学和机械性能产生显著影响,因而受到广泛关注.为使其性能得到切实改善,需要使无机纳米材料在高分子基质中均匀分散.对其分散状态的检测传统方法是对材料进行超薄、连续切片后,用透射电子显微镜(TEM)进