金属钴对泡沫型镍电极及Ni/MH电池性能的影响

活 性物质 为化学共 沉积锌的 Ｎｉ（ Ｏ Ｈ） ２ ,并 物理 掺杂 钴粉 的泡 沫镍 涂 膏式 镍电 极 表现出高的 放电比 容量和循 环稳定性 ,其中 钴 可以 显著 提 高镍 电 极活 性物 质 利用 率, 这是 由于 第 一次活化充 电时由 Ｃｏ 形 成导电 性能良好 的 Ｃｏ Ｏ Ｏ Ｈ 提高了放 电深度, 循环过程 中的容量 稳定 性是 锌和钴协同 作用的 结果,特别 是共沉 积锌,它可 以抑制 γ＿ Ｎｉ Ｏ Ｏ Ｈ 的形成 从而缓 解镍电极 的膨胀 ．     

On-Line Coupling of Separation Techniques to NMR

The hyphenation of chromatographic separation techniques with NMR spectroscopy is one of the most powerful and time-saving methods for the separation and structural elucidation of unknown compounds and molecular compositions of mixtures. Most of the routinely used NMR flow-cells have detection volumes between 40–180 μL for conventional separations with analytical columns, and the newest designs employ detection volumes in the order of 200 nL for capillary separations. The low flow rates used in capillary chromatography permit the use of deuterated solvents. Unequivocal structural assignment of unknown chromatographic peaks is possible by two-dimensional stopped-flow capillary HPLC-NMR experiments.     

风速分布形状对空调中翅片管蒸发器性能的影响

通过建立空调蒸发器分布参数模型,并对模型进行了验证,进而研究了四种不同风速场对R22和R290翅片管蒸发器流动和换热性能的影响规律。研究表明:在上三角型、下三角型和三角型风速场分布下,蒸发器单位面积换热量、质量流量以及压降均较均匀风速场降低;上三角型较均匀型单位面积换热量下降达7%左右,下三角型和三角型较均匀型下降4%左右;在不同风速场下,各换热温差基本持平,总传热系数起主导作用;R290质量流量均较R22小40%左右,且压降均较R22小24%左右。在满足换热量的要求下,R290在协调压降与质量流量具有一定的优势,可以作为现有空调制冷剂R22的环保型替代工质。     

微矩形槽平板热管的设计制造及性能分析

目前微槽平板热管成为热管研究和开发的重点。文中简要介绍了平板热管的设计要点及制造工艺,并通过实验,对设计制作的平板热管进行了性能测试。得出如下结论:该平板热管具有良好的启动特性和工作特性;在设计中要注意工质与管壳材料的相容性;制作时要严格控制清洗、检漏、充装等关键工序以保证制作质量。     

含磺酸基团的含氟嵌段共聚物的溶液性能及其应用

利用原子转移自由基聚合以及随后的磺化反应合成了一系列具有不同含氟量和磺化度的嵌段共聚物P(SSt b FNEMA) (PSSF) .通过溶液粘度和表面张力的测定 ,研究了该含氟嵌段共聚物独特的溶液行为 .实验结果表明 ,PSSF能显著降低N 甲基吡咯烷酮溶液的表面张力 .然而 ,与N 甲基吡咯烷酮溶液的表面性能不同 ,PSSF不能显著地降低水溶液的表面张力 ;当PSSF中和成钠盐后 ,水溶液的表面张力趋于一致 .进一步通过TEM、1 H NMR考察了PSSF在不同溶液中的形态 ,发现PSSF在水溶液中以核壳结构存在 ,而在N 甲基吡咯烷酮溶液中主要以胶束的形式存在 .初步考察了PSSF对聚氨酯脲 丙烯酸酯 (PUA)复合水分散液的改性效果 ,发现只需加入少量的PSSF ,就可使PUA膜的吸水率从原来的 10wt%下降到 4wt% .     

线性滑轨支撑微型斯特林制冷机的开发及性能调试

介绍了独立开发的采用线性滑轨支撑的微型整体式斯特林制冷机,对结构设计的要点进行了详尽的分析,指出采用线性滑轨支撑将大大改善旋转电机驱动斯特林制冷机的可靠性.文中还介绍了对影响制冷机性能特性的因素进行综合试验的情况.     

泡腾保健品中维生素E的高效液相色谱法测定

采用反相 Apollo C1 8柱 ,甲醇 /水 (98/ 2 ,V/ V)为流动相 ,流速为 0 .8m L / min,检测波长为 2 92 nm,建立了一种测定泡腾保健品 (大豆异黄酮 VE VC)中 VE的高效液相色谱测定方法。VE在浓度为 0 .0 5 38—0 .4 30 4 mg/ m L内有良好的线性关系 ,回归方程为 y=4 .87× 1 0 6x 7.1 2× 1 0 4(r=0 .9999) ,平均回收率98.0 9%。该法简便、快速、准确。     

高效液相色谱法测定富马酸异哌丙吡仑

采用高效液相色谱法测定富马酸异哌丙吡仑的含量。色谱柱为 DIKMATMRPC18(4 .6 mm× 2 0 cm,5 μm) ,流动相为乙腈 - 0 .5 %十二烷基硫酸钠 -三乙胺 (5 5∶ 4 5∶ 0 .2 ) ,用冰醋酸调 p H值至 7.0± 0 .1;流速为 1.0 m L/ min,检测波长为 2 6 5 nm。该方法回收率为 99.8% ,RSD=0 .4 4%。富马酸异哌丙吡仑在浓度为0 .0 5 92 8— 0 .1383mg/ m L范围内线性关系良好。相关系数为 r=0 .9997。该方法操作简便 ,结果准确可靠。     

Vegetable oil-based flame retardant epoxy/clay nanocomposites

Flammability of epoxy appears to be one of the greatest threats and hence limits its advanced applications. The present investigation, therefore, reports on vegetable oil-based self-extinguishing epoxy/clay nanocomposites for the first time. These nanocomposites were prepared by the ex-situ technique using mechanical shearing and ultrasonication at different loadings (1, 2.5 and 5 wt%) of nano-clay. Monoglyceride of Mesua ferrea L. seed oil, bisphenol-A and tetrabromobisphenol-A based epoxy resin was used as the matrix. XRD, TEM, SEM, FTIR and rheological studies confirmed partially exfoliated nanocomposites formation. The study demonstrates two fold improvements of tensile strength and scratch hardness, three-fold increase in adhesive strength and 20 units increase in gloss value without any change in impact resistance through nanocomposite formation. TG studied confirmed the enhancement of thermal stability of the nanocomposite by 25 °C. The limiting oxygen index values and UL 94 test indicated the self-extinguishing characteristic of the nanocomposites.     

Speciation of antimony in airborne particulate matter using ultrasound probe fast extraction and analysis by HPLC-HG-AFS

A fast extraction procedure has been developed for Sb(III) and Sb(V) oxoanions speciation in airborne particulate matter samples. Different extraction media (diammonium tartrate, hidroxilammonium clorhidrate, citric acid + ascorbic acid, phosphoric acid and citrate solutions) were tried, with assistance of an ultrasonic probe. The operation power and time of extraction were also optimized. The higher extraction recoveries were obtained with a 100 mmol L⁻¹ hidroxilammonium clorhidrate aqueous solution assisted by the ultrasound probe operated at 50 W during 3 min. The extracts were analyzed by HPLC-HG-AFS. The chromatographic separation of Sb(III) and Sb(V) was also optimized using diammonium tartrate and phthalic acid as mobile phases. The separation of both Sb species was performed in less than 3 min under isocratic conditions, using a 200 mmol L⁻¹ diammonium tartrate solution. The proposed extraction procedure and the HPLC-HG-AFS instrumental coupling have been successfully applied to airborne particulate matter samples, with high Sb content, collected in heavy traffic streets from Buenos Aires (Argentina). The results showed the presence of both Sb species at similar concentrations in the ng m⁻³ level. The extraction yield was higher than 90% for all the analyzed samples.