高振实密度圆饼状LiFePO4/C的制备及电化学性能

以乙二醇为溶剂,采用溶剂热法一步合成圆饼状LiFePO₄,然后以葡萄糖为碳源与合成的LiFePO₄前躯体高温烧结得到碳包覆的LiFePO₄/C复合材料,其振实密度高达1.3 g·cm^-3。采用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对LiFePO₄/C复合材料进行了物相和形貌表征,研究结果表明制备得到的LiFePO₄呈圆饼状,且生成的圆饼是由单晶LiFePO₄纳米片堆积而成。此外,LiFePO₄颗粒表面碳层包覆均匀。将制备的LiFePO₄/C用作锂离子电池正极材料,电化学性能测试表明其具有高的充放电比容量(在0.1C时放电,其初始放电比容量为157.7 mAh·g^-1)与良好的循环性能(500次循环后容量保持率为82.4%)。     

Behavior of lysozyme adsorbed onto biological liquid crystal lipid monolayer at the air/water interface

The interaction between proteins and lipids is one of the basic problems of modern biochemistry and biophysics.The purpose of this study is to compare the penetration degree of lysozyme into 1,2-diapalmitoyl-sn-glycero-3-phosphocholine(DPPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphoethano-lamine(DPPE) by analyzing the data of surface pressure–area(π–A) isotherms and surface pressure–time(π–T) curves.Lysozyme can penetrate into both DPPC and DPPE monolayers because of the increase of surface pressure at an initial pressure of 15 m N/m.However,the changes of DPPE are larger than DPPC,indicating stronger interaction of lysozyme with DPPE than DPPC.The reason may be due to the different head groups and phase state of DPPC and DPPE monolayers at the surface pressure of 15 m N/m.Atomic force microscopy reveals that lysozyme was absorbed by DPPC and DPPE monolayers,which leads to self-aggregation and self-assembly,forming irregular multimers and conical multimeric.Through analysis,we think that the process of polymer formation is similar to the aggregation mechanism of amyloid fibers.     

基于负性光刻胶掩膜的湿法多晶硅制绒

提出了一种用于大规模多晶硅太阳能电池生产的制绒工艺,采用负性光刻胶作为湿法刻蚀的掩膜,制备蜂巢状低反射率绒面.通过研究氢氟酸/硝酸溶液中各向同性刻蚀时腐蚀坑的形成过程,发现随着刻蚀时间的增加,在掩膜图形的开孔下逐渐形成六方分布的球面形状的腐蚀坑,腐蚀坑的深径比(深度/开孔直径)出现先上升然后下降的趋势.同理论计算值对比发现,随着刻蚀时间增加,掩膜和硅片的附着紧密性及掩膜的阻挡效应降低,酸液可能渗入了掩膜和硅片的界面,横向刻蚀速度快速上升,降低了深径比,导致实际的反射率高于理论计算值.尽管如此,本文还是成功制备了孔径15微米的蜂巢状绒面,反射率达到了22.9;.     

原子吸收法测定矿石中的铟

近年来,有用原子吸收法测定矿石中微量铟,但方法的灵敏度以及干扰元素的消除等问题,有待进一步改进。本试验在H_2SO_4-KBr介质中,以甲基异丙基甲酮萃取分离铟,并应用柠檬酸、酒石酸-抗坏血酸和硫脲掩蔽铁、铜、锌、铬等等干扰元素,使方法的灵敏度和选择性有所提高,应用于矿石、岩石中锢的测定(含铟量为0.0000x—0.x％),获得较好的结果。本法的灵敏度为0.2ppm/1％,回收     

二氧化锆薄膜制备及其特性测量

在室温下采用电子束蒸发的办法制备二氧化锆（ZrO2）薄膜。 借助紫外分光光度计、原子力显微镜（AFM）、X射线衍射（XRD）等方法研究了薄膜的透射率和表面结构。 同时研究了不同退火温度对薄膜物理性质的影响。在退火温度700,900,1 050 ℃时显微镜图像没有明显差别。随着退火温度的变大，薄膜表面的晶粒的直径逐渐变大，但粒径均在25 nm左右。当退火温度达到1 150 ℃时，粒径变得很大(约400 nm)。在700,900,1 050 ℃下退火后的薄膜的X射线衍射谱没有明显差别。在退火温度1 150 ℃下出现了较高的峰，研究结果表明:退火温度的增加，大量大粒径二氧化锆单晶晶粒出现，使得二氧化锆薄膜的漏电流增大，从而导致其热稳定性变差。     

高振实密度圆饼状LiFePO_4/C的制备及电化学性能

以乙二醇为溶剂,采用溶剂热法一步合成圆饼状LiFePO_4,然后以葡萄糖为碳源与合成的LiFePO_4前躯体高温烧结得到碳包覆的LiFePO_4/C复合材料,其振实密度高达1.3 g·cm~(-3)。采用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对LiFePO_4/C复合材料进行了物相和形貌表征,研究结果表明制备得到的LiFePO_4呈圆饼状,且生成的圆饼是由单晶LiFePO_4纳米片堆积而成。此外,LiFePO_4颗粒表面碳层包覆均匀。将制备的LiFePO_4/C用作锂离子电池正极材料,电化学性能测试表明其具有高的充放电比容量(在0.1C时放电,其初始放电比容量为157.7 mAh·g~(-1))与良好的循环性能(500次循环后容量保持率为82.4%)。     

在气/液界面牛血清蛋白对阴离子磷脂DPPG脂单层膜的动态行为和形貌变化的影响

The interaction between bovine serum albumin (BSA) and the anionic 1.2-dipalmitoyl-snglycero- 3-(phospho-rac-(1-glycerol)) (sodium salt) (DPPG) phospholipid at different subphase pH values was investigated at air-water interface through surface pressure measurements and atomic force microscopy (AFM) observation. By analyzing surface pressure-mean molecular area (π-A) isotherms, the limiting molecular area in the closed packing state-the concentration of BSA (A_lim-[BSA]) curves, the compressibility coefficient-surface pressure (C_S^-1-π) curves and the difference value of mean molecular area-the concentration of BSA (ΔA-[BSA]) curves, we obtained that the mean molecular area of DPPG monolayer became much larger when the concentration of BSA in the subphase increased at pH=3 and 5. But the isotherms had no significant change at different amount of BSA at pH=10. In addition, the amount of BSA molecules adsorbed onto the lipid monolayer reached a threshold value when [BSA]>5×10^-8 mol/L for all pHs. From the surface pressure-time (π-t) data, we obtained that desorption and adsorption processes occurred at pH=3, however, there was only desorption process occurring at pH=5 and 10. These results showed that the interaction mechanism between DPPG and BSA molecules was affected by the pH of subphase. BSA molecules were adsorbed onto the DPPG monolayers mainly through the hydrophobic interaction at pH=3 and 5, and the strength of hydrophobic interaction at pH=3 was stronger than the case of pH=5. At pH=10, a weaker hydrophobic interaction and a stronger electrostatic repulsion existed between DPPG and BSA molecules. AFM images revealed that the pH of subphase and [BSA] could affect the morphology features of the monolayers, which was consistent with these curves. The study provides an important experimental basis and theoretical support to understand the interaction between lipid and BSA at the air-water interface.     

掺钇二氧化锆薄膜制备及其特性测量

采用电子束蒸发法在室温下制备出掺钇二氧化锆薄膜.借助紫外分光光度计、原子力显微镜(AFM)、X射线衍射(XRD)方法研究了薄膜的透射率、表面结构.同时研究了不同退火温度下对薄膜光学性质的影响.研究的结果表明:退火温度的增加,使得二氧化锆薄膜的漏电流增大,从而导致其热稳定性变差.不同浓度三氧化二钇的掺杂对其透射率影响很小.     

牛血清蛋白对二硬脂酰基磷脂酰乙醇胺单层膜结构的影响

利用Langmuir-Blodgett(LB)技术结合原子力显微镜(AFM),研究了牛血清蛋白(BSA)在气/液界面上对二硬脂酰基磷脂酰乙醇胺(DSPE)单层膜结构的影响.通过改变亚相的pH值和BSA浓度,获得了不同条件下DSPE单层膜的等温线、吸附曲线和压缩循环曲线等.实验结果表明,亚相中BSA的存在对DSPE单层膜的压缩性、稳定性以及相变行为产生了较大的影响.吸附动力学结果表明,DSPE单层膜对BSA分子的吸附量存在一定的阈值,且该阈值的大小与亚相pH值相关.通过分析实验数据可知,当亚相pH=3时,BSA的疏水残基几乎全部暴露在外面,2种分子之间的相互作用最强;而pH=7时,BSA仅有少量的疏水残基暴露在外面,2种分子之间的相互作用最弱.原子力显微镜观测到的单层膜形态变化特点与曲线分析结果一致.该研究为了解牛血清蛋白与磷脂分子之间的相互作用机理提供了重要的实验基础和理论依据.     

离子束刻蚀碲镉汞晶体的电学特性研究

本文利用迁移率谱分析了离子束刻蚀后的碲镉汞晶体, 发现180 μm的p型碲镉汞晶体在刻蚀后完全转为n型, 且由两个不同电学特性的电子层组成:低迁移率的表面电子层和高迁移率的体电子层. 通过分析不同温度下的迁移率谱, 表明表面电子层的迁移率不随温度而变化, 而体电子层的迁移率随温度的变化与传统的n型碲镉汞材料一致. 不同厚度下的霍尔参数表明体电子层的电学性质均匀. 另外, 通过计算得到表面电子层的浓度要比体电子层高2-3个数量级.