聚间苯二甲酰间苯二胺中空纤维膜研究

以聚间苯二甲酰间苯二胺(PMIA)为成膜聚合物,N,N-二甲基乙酰胺(DMAc)为溶剂,氯化钙(Ca Cl2)、氯化锂(Li Cl)和聚乙二醇(PEG)为添加剂,调制铸膜液,采用干—湿法纺丝技术制备了PMIA中空纤维膜.研究表明,PEG的加入可显著提高PMIA中空纤维膜的纯水通量,而随PEG添加量增加,膜的纯水通量呈现先增加后减小趋势;膜对牛血清蛋白(BSA)有较好的截留性能,截留率可达92%;膜具有良好的亲水性能,膜对纯水接触角可低至44°;膜的断裂强度达5.8 MPa,具有较好的力学性能,以及良好的耐热水和耐碱性能,可用于高温和碱性水处理等领域.     

Stabilization of electronic properties of (1R)-(−)-10-camphorsulfonic acid doped polyaniline by UV irradiation

Stability of electronic parameters of conducting polymers affects the overall performance of organic electronics. We show that UV light (254 nm) treatment of polyaniline (PANI) films, containing camphorsulfonic acid (CSA) as a dopant and cast from formic acid, decreases the film resistance and keeps their improved resistance stable for at least 4 months. It has been found that due to the different origins of these electronic properties, the resistance and work function of the PANI·CSA films are affected differently by the UV treatment. The long-term stability of the resistance is governed by morphological changes of the material. On the other hand the stability of the threshold voltage of the field-effect transistor (FET) which is an indirect measure of the work function, originates from the charge density equilibration at the PANI·CSA film/insulator interface. The FT-IR, UV-vis and circular dichroism data provide the evidence that after the UV treatment the polymer molecular structure remains intact, but some secondary structural re-arrangements of the PANI·CSA take place. These re-arrangements are resulting from the strong donor-acceptor interactions between the imine and/or amine groups of the PANI chains and the CO and SO₃⁻ groups of the doping CSA-anion. These interactions enhance significantly the mechanical rigidity of the PANI matrix. The increasing broad absorption band of the “free-carrier tail” in the FT-IR spectra correlates with the conductivity increase of the UV treated PANI·CSA film.     

5个中华按蚊种群对溴氰菊酯的抗性及抗性选择反应

经浙江省 5个中华按蚊自然种群和敏感品系对溴氰菊酯抗性测定 ,发现其致死中浓度 ( LC50)都比各自的敏感品系高 ,特别是来自温州的中华按蚊 ,其抗性比率 ( RR50)达 11倍之多 . 将各自然种群的蚊虫进行抗性筛选 12代 ,发现其抗性水平与敏感品系相比 ,高达 130～ 190倍; 与其自然种群相比达 10～40倍 . 来自温州种群的抗性品系的选择性反应 ( R值 )小于 0. 1,而其它抗性品系大于 0. 1,这表明从抗性概率较高的自然种群中筛选的抗性品系 ,其抗性增加速率低于那些从抗性概率较低的自然种群中所筛选的抗性品系 ,即 5个自然种群的抗性潜能应该是相似的 . 最后对相应的蚊虫防治策略进行了讨论 .     

Properties of a large La1.92Sr0.08CuO4+δ single crystal grown by the travelling-solvent floating-zone method

A centimeter size single crystal of La_2−xSr_xCuO_4+δ (volume=1.32 cm³) with x_Sr=0.08 has been grown by the travelling-solvent floating-zone (TSFZ) method using a double ellipsoidal-type optical furnace as the heat source. The crystallised phase was checked solvent free by X-ray powder diffraction experiments, the crystal dimensions and quality being investigated by X-ray and neutron Laüe techniques. Several rocking curves of the Bragg peaks were performed by neutron diffraction giving a full width at half maximum (FWHM) of 0.200° for (006) reflection and clearly showing the presence of twin domains as expected for such an orthorhombic structure. The superconducting critical temperature of the as-grown crystal under 2 oxygen bar was determined by SQUID measurements with T_c=18–20 K. Thermal treatments at different oxygen pressures were carried out showing no significant improvement of the transition sharpness and the T_c value. Normal state susceptibility was also measured from 6 to 800 K for two different field orientations and can be interpreted as an antiferromagnetic insulating state behaviour. The resistivity measurements display an insulating behaviour perpendicular to the CuO₂ planes and a metallic behaviour in the planes, with a high anisotropy ratio R_c/R_b350 at room temperature and a zero resistivity achieved at 27 K in both directions. The specific heat measurements have revealed no anomalies in the temperature range 15–300 K.     

热喷涂铝涂层在3.5%NaCl溶液中阻抗谱随温度变化规律的研究

利用浸泡法以及电化学阻抗谱研究了铝涂层在3.5%NaC l溶液中不同温度下涂层电阻的变化。实验结果表明:铝涂层氧化膜对腐蚀介质的隔离能力随溶液温度升高而减弱,涂层电阻随着溶液温度的升高而降低。     

含贵金属的BaZrO3 储存NOx 催化剂结构及性能研究

A series of perovskite-type BaZrO3 catalysts are prepared by the sol-gel method. Their NOx storage capacity（NSC）and the resistance of SO2 poison are measured. XRD,XPS and FT-IR techniques are also used to characterize their structures and the influence of the structures on performance. The results indicate that,after calcinations at 750 and 900 ℃,the Ba and Zr species mainly exist in the form of perovskite BaZrO3 phase,and the BaCO3 and ZrO2 phases also exist. The presence of bulk nitrate is shown by XRD and FT-IR after BaZrO3 absorbing NOx . The Rh/BaZrO3 is prepared by doping 0.5%Rh on the BaZrO3 with the impregnation method. It is found that the Rh mainly deposits on the surface of catalyst. However,the noble metals 0.5% Rh or Pt well disperse on the surface of the sample after the BaZrO3 is mixed with γ-Al2O3 in equal weight proportion. The structure of perovskite BaZrO3 may be partly broken after doping Rh or Pt,because of the reduction by hydrogen in the process of preparing samples,and then some ZrO2 is enriched on the surface. The BaZrO3 catalysts possess high NSC and high resistance ability of SO2 poison. The NSC of Rh/BaZrO3 decreases compared to that of BaZrO3 . However,the NSC of the samples Pt/BaZrO3/γ-Al2O3 and Rh/BaZrO3/γ-Al2O3 increases by 78% and 15% respectively. It is noticed that the NSC enhances for all the samples containing noble metal Pt or Rh duing the 0.01%SO2 mixed with the NO and O2 . It implies that the NO oxidation is improved by SO2 .     

Study on resistance coefficient in compound channels

This paper presents a further study of the Manning and Darcy-Weisbach resistance coefficients, as they play a significant role in assessing the cross-sectional mean velocity, conveyance capacity and determining the lateral distribution of depth mean velocity and local boundary shear stress in compound channels. The relationships between the local, zonal and overall resistance coefficients, and a wide range of geometries and different roughness between the main channel and the flood plain are established by analyzing a vast amount of experimental data from a British Science and Engineering Research Council Flood Channel Facility (SERC-FCF). And the experimental results also show that the overall Darcy-Weisbach resistance coefficient for a compound channel is the function of Reynolds number, but the function relationship is different from that for a single channel. By comparing and analyzing the conventional methods with the experimental data to predict composite roughness in compound channels, it is found that these methods are not suitable for compound channels. Moreover, the reason why the conventional methods can not assess correctly the conveyance capacity of compound channels is also analyzed in this paper.The project supported by the National Natural Science Foundation of China (50279024), the National Key Basic Research and Development Program of China (973 Program) (2003CB415202) and the Specialized Research Fund for the Doctoral Program of Higher Education (20030610039)The English text was polished by Ron Marshall     

基于一般化三电极的山区输电杆塔接地电阻测量方法

介于0.168布极法、三角形法和钳表法在测量山区复杂地形条件下杆塔接地电阻方面的某些局限性,提出将便于灵活布线的一般化三电极布线法应用于山区复杂地形输电线路杆塔接地电阻的测量中,并将其测量结果同规范中推荐的三极三角形法和钳表法的测量结果进行对比分析。研究结果验证了本文采用的杆塔接地电阻测量方法的正确性和工程可行性,为山区复杂地形条件下的架空输电线路杆塔接地电阻测量提供新的方法。     

ITO材料在减反射膜设计中的应用

改变ITO材料通常作为透明导电膜单独使用的状况,将其作为减反射膜系中的一层,能够在很大程度上增加ITO透明导电膜在可见光部分的透过率.通过使用将ITO材料置于膜系的内层和最外层两类不同的设计思想,可以使ITO透明导电膜达到相当优良的应用效果.使用低压反应离子镀方法制备了设计的两类减反射膜系,实验证明,膜层在可见光部分的透过率显著提高,剩余反射率明显下降,并得到了平均透过率为95.83%,最高透过率达到97.26%,方块电阻为13.2～24.6Ω/□的试验结果.     

六氟化硫组合开关设备在鲁新煤矿的应用

六氟化硫负荷开关是一种开断能力比较强的开关.普通的负荷开关采用的是空气灭弧,而六氟化硫负荷开关触头密封于六氟化硫气仓内,利用六氟化硫的高绝缘性能灭弧.。随着国民经济的发展需要,高压配电SF6的装置广泛应用于城区变电站、工业变电站。做好SF6的安装、维护,能保证电力系统的安全运行。