根据零惯量模型推求膜孔灌溉田面综合糙率系数

根据膜孔灌溉田面水流运动特性，将膜孔灌溉不连续的入渗界面等效概化成均匀连续的透水界面，对膜孔灌水流推进阶段采用四边形曲线差分网格，消退阶段采用矩形差分网格进行计算，建立了膜孔灌溉田面水流运动零惯量数学模型，并将其与优化理论相结合，提出了确定膜孔灌溉田面综合糙率系数的优化模型。实例计算与方法验证表明，该方法能够简单而有效地确定膜孔灌溉田面综合糙率系数。     

纳米TiO2的制备及其在环境净化方面的应用

综述了近年来TiO2粉体及薄膜光催化剂的制备方法,及光催化在环境净化和其它方面的应用进展,展望了TiO2光催化剂的发展研究方向.     

聚电解质逐层自组装生物矿化材料

通过人工模拟的方法,利用阴阳离子型聚电解质溶液制得自组装膜. 将装有该自组装膜的玻璃基片放入模拟体液SBF中,选择适当的条件,可诱导羟基磷灰石在其上面的沉积. 实验结果表明:SBF溶液的pH值对羟基磷灰石在膜上的诱导结晶特性有较大的影响;当pH值为7.40时,利用自组装膜和SBF模拟体液进行生物矿化得到的晶体最为细致紧密. 诱导矿化实验表明,利用聚电解质稀溶液制成的自组装膜可以成功地进行生物矿化材料的研究.     

316L不锈钢在醋酸溶液中的钝化膜电化学性质

通过电化学阻抗方法测量316L不锈钢在25～85 ℃的醋酸溶液中的EIS曲线和Mott-Schottky曲线,并测量各温度点下的循环伏安曲线,研究了钝化膜的电化学性质. 研究结果表明:在醋酸溶液中的阻抗谱表明316L不锈钢在25～85 ℃温度范围内均能形成稳定的钝化膜,随温度升高极化阻力下降而界面电容增大. 温度对于316L不锈钢钝化膜的半导体本征性质没有根本的影响:在-0.5～0.1 V电位区间内钝化膜呈p型半导体特征;在0.1～0.9 V电位区间内钝化膜呈n型半导体特征;在0.9～1.1 V电位区间内钝化膜呈p型半导体特征. 钝化膜的循环伏安曲线显示当温度低于55 ℃时,钝化膜结构比较稳定;当温度为55 ℃时,钝化膜稳定性趋向恶化;当温度超过55 ℃时,钝化膜稳定性下降.     

天然生漆膜化学镀镍工艺的研究

研究了天然生漆基材上的化学镀镍工艺条件,通过改变施镀工艺的pH值、温度、时间以及镀液配方中主盐质量浓度、还原剂质量浓度,得到不同条件下的化学镀层厚度、外观和镀速等实验结果.并用扫描电镜(SEM)、动态机械热性能(DMTA)、示差扫描量热分析(DSC)和热重分析(TG)等手段研究镀层的形态与性能.该工艺可在生漆膜表面镀上一层均匀、色泽光亮的金属镍膜,其粒径大小匀称、排布规整、镀层致密;生漆/镍金属复合膜的耐热性显著提高.     

单组分快干型聚氨酯透明膜材料的制备

介绍以聚醚-N220，聚醚-403，TDI-80等为原料制备单组分快干型聚氨酯透明膜材料的方法和原理，研究了TDI-80用量、聚醚-403的添加量以及催化剂对透明膜的耐化学腐蚀、耐油、表干时间等性能的影响，并通过红外光谱对膜材料组成进行了表征。所得制品固化时间短、透明度高、化学稳定性好、使用方便，可用于化工仪器设备的防尘、防油污、防腐等表面保护。     

An electrochemical impedance spectroscopic study of the electronic and ionic transport properties of LiCoO2 cathode

The storage behavior and process of the first delithiation-lithiation of LiCoO2 cathode were investigated by electrochemical impedance spectroscopy(EIS). The electronic and ionic transport properties of LiCoO2 cathode along with variation of electrode potential were obtained in 1 mol·L?1 LiPF6-EC:DMC:DEC electrolyte solution. It was found that after 9 h storage of the LiCoO2 cathode in electrolyte solu-tions,a new arc appears in the medium frequency range in Nyquist plots of EIS,which increases with increasing the storage time. In the charge/discharge processes,the diameter of the new arc is reversi-bly changed with electrode potential. Such variation coincides well with the electrode potential de-pendence of electronic conductivity of the LiCoO2. Thus this new EIS feature is attributed to the change of electronic conductivity of LixCoO2 during storage of the LiCoO2 cathode in electrolyte solutions,as well as in processes of intercalation-deintercalationtion of lithium ions. It has been revealed that the reversible increase and decrease of the resistance of SEI film in charge-discharge processes can be also ascribed to the variation of electronic conductance of active materials of the LiCoO2 cathode.     

Low-field positive and high-field negative magnetoresistances in multiphase Fe-oxide thin films at room temperature

Multiphase Fe-oxide thin films are fabricated on glass substrates by a facing-target sputtering tech- nique. X-ray diffraction and X-ray photoelectron spectroscopy reveal that Fe, Fe3BO4, γ -Fe2BO3B and FeO coexist in the films. High resolution transmission electron microscopy shows the well-defined colum- nar grain structure with the unoxidized Fe as the core and iron-oxide as the shell. The low-field positive and high-field negative magnetoresistances coexist in such a system at room temperature, which can be explained by considering a shell/core model. Nonlinear current-voltage curve and photovoltaic effect further confirm the tunneling-type conduction.     

SiC薄膜的制备及其光敏特性

采用热丝化学气相沉积(HFCVD)方法,以甲烷、硅烷和氢气为反应气体在单晶硅衬底上沉积碳化硅(SiC)薄膜材料.通过X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)对SiC薄膜的晶体结构进行测试分析.利用原子力显微镜(AFM)对SiC薄膜的表面形貌进行分析.对该薄膜在室温和较高温度(410℃)下进行光敏特性测试,结果表明:该薄膜为SiC薄膜且对不同波长、不同功率的光有一定的敏感特性,较高温度下其敏感特性和室温下测试的结果大体一致,在高温光敏器件领域具有很大的应用潜力.     

铕离子掺杂普鲁士蓝复合汞膜电极上替硝唑的方波伏安法测定

采用电化学沉积法制备了新型铕离子掺杂普鲁士蓝复合汞膜电极(PB-Eu composite mercury fil melectrode),建立了在该电极上应用方波伏安法测定实际样品中替硝唑(Tinidazole,简称TNZ)含量的方法.结果表明,在BR(pH=6.0)缓冲溶液中,TNZ在-0.558 V(vs.SCE)产生一个清晰的还原峰,且具有明显的吸附波特性.在最佳实验条件,恒电位富集1.5 min时,其还原峰电流与TNZ的浓度在2.5×10-6~5.0×10-4mol/L(r=0.999 2)和2.5×10-8~7.5×10-7mol/L(r=0.999 4)两段浓度区间内有良好的线性关系,最低检测下限为2.0×10-9mol/L(S/N=3),相对标准偏差为2.2%(n=10).该法用于片剂和注射液中替硝唑含量测定的稳定性和重现性好,线性范围较宽.