SPE电极上Pt单组分及Pt-Au双组分还原态CO_2阳极剥离电化学氧化行为研究

采用循环伏安法，对ＳＰＥＰｔ电极以及ＳＰＥＡｕ－Ｐｔ电极上还原态ＣＯ２的电化学氧化行为研究表明，此类电极的电化学特性与光滑Ｐｔ电极一致：ＣＯ２在氢原子吸附电位区０～２５０ｍＶ（ｖｓ．ＲＨＥ）处，可与电极上化学吸附的氢反应，生成还原态的ＣＯ２，通过线性扫描，还原态ＣＯ２即发生一不可逆电化学氧化过程（阳极剥离）．在ＳＰＥＰｔ系列及ＳＰＥＡｕ－Ｐｔ系列上ＣＯ２的电化学行为表明，当ＳＰＥＰｔ系列上Ｐｔ的载量为２．５ｍＬ的０．０１ｍｏｌ·Ｌ－１Ｈ２ＰｔＣｌ６的Ｐｔ时，对还原态ＣＯ２的电催化活性最好，当Ｐｔ的载量相同时，在ＳＰＥＡｕ－Ｐｔ上，催化剂对还原态ＣＯ２的电化学氧化行为比ＳＰＥＰｔ电极更强，这是由于预先沉积的Ａｕ对后沉积的Ｐｔ有调制作用．     

The role of OH ions in the stabilization of F colour centres in LiF

Thermally Stimulated Depolarisation Current (TSDC) and optical methods are applied to a range of alkali-fluoride crystals in order to establish a model for the stable F ₂ ⁺ - like colour centres in LiF:OH^-. The experimental results for LiF:OH^- suggest that the OH^- defects are partially destroyed under ionising irradiation or during crystal growth. The low-temperature dielectric relaxation signals in LiF:OH^- and LiF:Mg²⁺,OH^- are attributed to highly interacting hydroxide ions and products of their destruction located in extended lattice defects. In LiF:OH^-, in contrast to other alkali halides, the results advocate for a defect-structure model, which considers a neutral defect (ND, probably O₂ or H₂) sited at the anion vacancy of the O^2--V _a ⁺ dipole and which possibly is the “nucleus” for the F ₂ ⁺ centre. The proposed F ₂ ⁺ (ND, O^-) model seems to better explain the dielectric results, compared to the older F ₂ ⁺ (O^2-) and F ₂ ⁺ (O^-) models. The estimate for the electric dipole moment derived from the experimental TSDC bands, gives a value for the F ₂ ⁺ - like centre in LiF:OH^- between those of the F ₂ ⁺ (O^-) and F ₂ ⁺ (O^2-) defects, in good agreement with the proposed F ₂ ⁺ (ND,O^-) model. The reduction of the activation energy barrier of the (re)orientation process of the Mg²⁺V _c ^- (OH^-) complexes in LiF:Mg²⁺,OH^-, and the low-temperature shift of their TSDC band, compared to the single Mg ₂ ⁺ V _c ^- peak in LiF:Mg²⁺, are tentatively ascribed to an increase in the crystal-lattice parameters owing to the presence of OH^- and/or products of its destruction. Received 31 August 2001 / Received in final form 30 March 2002 Published online 9 July 2002     

HPLC法测定阿奇霉素葡萄糖注射液中阿奇霉素的含量

利用高效液相色谱法，以VP-ODS型色谱柱，乙腈-异丙醇-水-氨水（60：25：15：0.1)为流动相，于210nm波长处测定了阿奇霉素葡萄糖注射液中阿奇霉素葡萄糖注射液中阿奇霉素的含量。阿奇霉素的浓度在0.75-1.75mg/mL线性关系良好，线性方程的A=881910.4c-16208.2，相关系数r=0.9999。阿奇霉素的平均回收率为99.59%，测定结果的相对标准偏差为1.31%。     

Time saving fluid dynamic predictions in a wetting-drying process: A hypothesis for vertisols

This paper is aimed at investigating the effect of the initial water content in a vertisol sample on the whole wetting-drying process leading the system to a change in volume. In order to do this, an experimental setup was realized and employed with very thin soil layers wetted from below (“per ascensum”). The results show that the effect of the initial water content on the swelling-shrinkage process is to shift the corresponding curve e-ϑ towards bigger-smaller values of the humidity but does not seem to affect the dynamics of the process. The text was submitted by the authors in English.     

慢速饮酒血液中酒精含量的数学模型

描述的是在一定时间内慢慢地匀速喝完一定数量酒的问题,并建立了相应的数学模型.同时也建立了快速饮酒的数学模型,以及证明了在各次饮酒后的某时刻酒精含量的可叠加性.     

二元合金微观偏析的相场法数值模拟

使用耦合溶质场的相场模拟研究了Ni-Cu二元合金枝晶生长过程中固相溶质扩散系数D_s 对枝晶形貌和微观偏析等的影响.计算结果表明，随着D_s的减少，固液界 面前沿溶质扩散层越薄，枝晶生长越有利，枝晶尖端生长的速度越大，侧向分支越发达；D< sub>s越小，固相中溶质成分的波动越强烈，随着D_s的增大，固相中溶质 成分的波动相应减小；溶质微观偏析程度随D_s的增大而减小. 关键词： 相场方法 微观偏析 固相扩散系数 数值模拟     

Synthesis and characterization of poly(ethylene oxide‐co‐ethylene carbonate) macromonomers and their use in the preparation of crosslinked polymer electrolytes

Methacrylate‐functionalized poly(ethylene oxide‐co‐ethylene carbonate) macromonomers were prepared in two steps by the anionic ring‐opening polymerization of ethylene carbonate at 180 °C, with potassium methoxide as the initiator, followed by the reaction of the terminal hydroxyl groups of the polymers with methacryloyl chloride. The molecular weight of the polymer went through a maximum after approximately 45 min of polymerization, and the content of ethylene carbonate units in the polymer decreased with the reaction time. A polymer having a number‐average molecular weight of 2650 g mol^?1 and an ethylene carbonate content of 28 mol % was selected and used to prepare a macromonomer, which was subsequently polymerized by UV irradiation in the presence of different concentrations of lithium bis(trifluoromethanesulfonyl)imide salt. The resulting self‐supportive crosslinked polymer electrolyte membranes reached ionic conductivities of 6.3 × 10^?6 S cm^?1 at 20 °C. The coordination of the lithium ions by both the ether and carbonate oxygens in the polymer structure was indicated by Fourier transform infrared spectroscopy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2195–2205, 2006     

Independence of the brittle–ductile transition from the rubber particle size for impact‐modified poly(vinyl chloride)

A series of acrylic impact modifiers (AIMs) with different particle sizes ranging from 55.2 to 927.0 nm were synthesized by seeded emulsion polymerization, and the effect of the particle size on the brittle–ductile transition of impact‐modified poly(vinyl chloride) (PVC) was investigated. For each AIM, a series of PVC/AIM blends with compositions of 6, 8, 10, 12, and 15 phr AIM in 100 phr PVC were prepared, and the Izod impact strengths of these blends were tested at 23 °C. For AIMs with particle sizes of 55.2, 59.8, 125.2, 243.2, and 341.1 nm, the blends fractured in the brittle mode when the concentration of AIM was lower than 10 phr, whereas the blends showed ductile fracture when the AIM concentration reached 10 phr. It was concluded that the brittle–ductile transition of the PVC/AIM blends was independent of the particle size in the range of 55.2–341.1 nm. When the particle size was greater than 341.1 nm, however, the brittle–ductile transition shifted to a higher AIM concentration with an increase in the particle size. Furthermore, the critical interparticle distance was found not to be the criterion of the brittle–ductile transition for the PVC/AIM blends. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 696–702, 2006     

Assessment of filtered gas–solid momentum transfer models via a linear wave propagation speed test

The propagation speeds of linear waves in gas–solid suspensions depend strongly on the solids volume fraction and the wave frequency. The latter is due to gas–solid momentum transfer and allows a simple test on filtered gas–solid momentum transfer models. Such models may predict linear wave propagation speeds different from those obtained with the non-filtered model at wave frequencies higher than the filter frequency, but not at wave frequencies lower than the filter frequency.     

Nd掺杂的Bi4Ti3O12变温X射线衍射分析

利用变温X射线衍射技术，在预烧过程中分析了Nd掺杂Bi4Ti3O12后生成Bi3.15Nd0.85Ti3O12（BNT）相的形成过程以及微结构的变化．实验观察到以30℃／min的升温速率，BNT相在700℃时开始形成，其衍射峰强度随温度的继续升高而增强，衍射峰半高宽随烧结时间延长而减小．X射线衍射分析结果表明，在900℃恒温条件下，烧结约2h，可形成单一的BNT相．