二水合草酸锰脱水过程的机理函数判别和动力学研究

本文用等温热重分析法和线性升温热重分析法研究了二水合草酸锰的脱水过程,提出了过程机理函数的三步判别法。实验测定和理论分析表明,MnC_2O_4·2H_2O的脱水过程受A_2机理支配,也就是一种随机成核和晶核随后生长的过程,其活化能E=75.49kl/mol,频率因子A=6.166×10_8min~(-1)。动力学补偿效应为:logA=0.1318E-1.2682     

海藻酸分子印迹聚合物的合成及其对锌离子的识别作用

将海藻酸钠与锌(II)配位形成配位聚合物膜,用FT-IR和DRS研究所得到的海藻酸-锌(II)配位聚合物(AA-Zn)的形成机理。将此配位聚合物与戊二醛(GA)进行交联,得到交联印迹聚合物前体,并用FT-IR光谱表征其结构。为了制备对Zn2+离子敏感的分子印迹聚合物(MIP),将前体聚合物浸入0.5 moL/L HCl溶液中48 h并搅拌,以洗脱Zn2+离子得到印迹聚合物(MIP-Zn)。洗脱液用UV-Vis光谱检测并验证,UV-Vis谱图显示Zn(II)的特征吸收峰在240 nm处,表明Zn2+离子已被洗脱。将制得的海藻酸钠-锌(II)印迹膜用于吸附Zn2+离子,结果表明印迹聚合物对Zn2+离子有较强的吸附能力。     

聚吡咯/海藻酸锰小球的性能研究

将海藻酸钠水溶液滴加到Mn Cl2水溶液中凝固成海藻酸锰小球。海藻酸锰小球吸附吡咯单体,在酸性KMn O4溶液中使吡咯单体氧化聚合成聚吡咯(PPy),得到聚吡咯/海藻酸锰复合小球(MPM)。用红外光谱仪、扫描电子显微镜和电化学工作站表征了复合小球的结构、形貌和电化学性能。结果表明:直径为200⁵00 nm的PPy微球聚集在海藻酸锰小球的表面。随着海藻酸钠在Mn Cl2水溶液的凝固时间增加,MPM的PPy含量偏低,复合小球的电容值减小。这种具有导电和生物相容性的MPM将在新型电极材料领域得到应用。     

壳聚糖-海藻酸钠包被猪血红蛋白微囊的制备

采用乳化凝胶法研制壳聚糖-海藻酸钠包被的猪血红蛋白微囊.结果表明:壳聚糖-海藻酸钠-血红蛋白微囊具有较佳的形态和较小的粒径,平均粒径1μm,且具有相对较窄的高斯分布;血红蛋白在微囊中包埋率超过90%,从微囊中持续释放时间达1个月以上.壳聚糖-海藻酸钠-血红蛋白微囊有望成为可供静脉注射用的具有缓释作用的人工携氧治疗剂.     

苯催化燃烧反应Cu-Mn-Ce-Zr-O催化剂催化活性的研究

用共沉淀法合成了铜-锰-铈-锆复合氧化物系列催化剂,用常压气体流动评价装置考查了其对苯蒸气的催化活性,并根据穿透曲线、XRD衍射对催化剂表面性质进行了分析。结果表明:CeO₂和ZrO₂对以铜、锰氧化物催化剂的催化活性有促进作用。     

Effect of rare earth and alloying elements on the thermal conductivity of austenitic medium manganese steel

The influence of different contents of Cr, Mo, and rare earth element (RE) additives on the thermal conductivity of austenitic medium manganese steel was studied and discussed. The results show that the addition of Cr in medium manganese steel can improved the ordering of C-Mn atomic clusters, so as to improve the steel's thermal conductivity. However, Cr will lead to precipitation of a great deal of carbides in medium manganese steel when its content is greater than 4wt%. These carbides would aggregate around the grain boundary, and as a result, the thermal conductivity is decreased. By the addition of Mo whose content is about 2wt%, spherical carbides will be formed, thus improving the thermal conductivity of the medium manganese steel. The interaction between rare earth elements and alloying elements will raise both the thermal conductivity and the wear-resisting property of medium manganese steel.     

Hardness of Mn2V2O7 thin films and its influential factors

Mn2V2O7 thin films were deposited onto amorphous glass substrates using a chemical bath deposition method and different deposition time. X-ray diffraction (XRD) analysis was used to define the structure of the films. Their roughness, thickness, and surface properties were evaluated through atomic force microscopy (AFM). The hardness of the films was measured using a nanohardness tester. The film thickness, average grain size, and roughness were positively correlated with each other. These three parameters were observed to increase with the deposition time. The film thickness and average grain size were inversely correlated with the hardness and rough-ness. In addition, the number of crystallites per unit area and the dislocation density were observed to be positively correlated with the hardness and roughness. This study was designed to elucidate and formalize the underlying reasons for these relationships.     

钛白废盐制备高纯MnO_2纳米棒

以钛白生产中产生的废盐为原料,采用水热法合成制备了高纯MnO2纳米棒,研究了不同反应条件对产品纯度和产率的影响.以纯度和产率为指针,确定了制备高纯MnO2纳米棒的最佳工艺条件,并对样品进行了XRD、FT-IR、SEM、ICP表征.研究结果表明,MnO2纳米棒的纯度随水热反应pH增大而增大,当pH为2.0时,制得的MnO2纳米棒纯度最大,继续增大pH,样品纯度下降,MnO2纳米棒的产率随水热反应pH增大而增大,当pH为4.0时,产率最大,继续增大pH,产率下降;当NaCl的加入量为0.08 g时,纯度和产率同时达到最大;MnO2纳米棒纯度几乎不随NaClO3加入量的变化而变化,而产率随着NaClO3加入量的增加而增加.     

锰矿制备白炭黑和硫酸锰的工艺研究

为提高锰矿中硫酸锰的浸取率,将锰矿粉与Na OH反应制备白炭黑了后,其滤渣再经酸浸制备硫酸锰.考察了反应温度、反应时间、配比、酸碱浓度等因素对白炭黑产率和锰浸出率的影响.结果表明:在140℃反应8 h,碱矿质量比为1.2∶1,Na OH水溶液质量百分比为40%时,白炭黑的产率可达15.7%.在100℃反应5 h,硫酸与滤渣的质量比为1.2∶1,硫酸水溶液质量百分比为20%时,硫酸锰的浸取率可达13.0%,较传统直接酸浸工艺的浸取率11.0%有所提高.     

原位观察MnS对非调质钢拉伸性能各向异性的影响

利用激光共聚焦扫描显微镜原位观察S质量分数为0.065%的非调质钢纵向与横向拉伸过程中MnS的行为,研究MnS形貌与分布对非调质钢各向异性的影响.原位观察表明锻后钢中存在大量长条形MnS,横向与纵向拉伸过程中MnS长度方向与拉力方向取向不同.横向拉伸过程中MnS更易与基体分离产生裂纹,裂纹随MnS长度方向扩展长大,最终导致基体的断裂. MnS在纵向拉伸时不易与基体分离,因此对纵向拉伸性能影响较小.钢中群聚分布的MnS有利于裂纹的聚合长大,会促进基体的断裂.