NUMERICAL SIMULATION OF FLOW OF HIGHLY VISCOELASTIC FLOW IN THREE－DIMENSIONAL VARYING THICK SLIT CHANNEL

（杨伯源）（李勇）ＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＦＬＯＷＯＦＨＩＧＨＬＹＶＩＳＣＯＥＬＡＳＴＩＣＦＬＯＷＩＮＴＨＲＥＥ－ＤＩＭＥＮＳＩＯＮＡＬＶＡＲＹＩＮＧＴＨＩＣＫＳＬＩＴＣＨＡＮＮＥＬ￥ＹａｎｇＢｏｙｕａｎ；ＬｉＹｏｎｇ（Ｄｅｐａｒｔ...     

氧化还原可逆Nb2TiO7复合阴极电解池高温水蒸气电解研究

系统地研究Nb₂TiO₇与Nb_1.33Ti_0.67O₄材料相互转变的氧化还原循环可逆性能,同时研究Nb2TiO7和Nb_1.33Ti_0.67O₄样品随温度和氧分压变化的电导率,并与复合电极对称电池和电解池的电化学性能相关联. 在830 oC下,对Nb_1.33Ti_0.67O₄复合电极电解池进行水蒸气的电解研究测试. 电流电压曲线和电解池短期性能测试表明在低电压下主要为电极的还原和活化过程;而在高电压下主要为水蒸气的电解. 当3%H₂O/Ar/4%H_{2气体通入阴极时电解池水蒸气电解的法拉第效率为98.9%;而当通入气体转换为3%H2O/Ar时效率为89%.}     

铜铟铝硒硫薄膜的低成本非真空混合法制备

采用溶剂热法制备出铜铟铝硒Cu(In,Al)Se₂ (CIASe)粉末,然后滴涂铜铟铝硒CIASe浆料获得前驱体薄膜,最后通过硒化/硫化过程制备出铜铟铝硒CIASe和铜铟铝硒硫CIASeS薄膜．通过XRD、SEM、XRF及光吸收等表征,发现所制备的薄膜为单相的黄铜矿结构,具有(112)择优取向．同时,在使用硫元素替代硒之后,薄膜的XRD主峰向高的2θ角度漂移,多孔薄膜也变得更加致密．薄膜带隙值也增加到更为合适的范围,从1.21 eV增加到1.33 eV,这也说明了硫化过程有利于提高CIASeS薄膜的质量．     

光栅投影相位法系统模型及标定方法

本文针对传统投影光栅相位法的光学三角法模型进行了改进,采用直入射光路并配合使用一种简便易行的标定方法,只需使用相移公式求取相位差,而不会引入与系统几何位置关系有关的量,简化了求取高度矩阵的要求。实验结果表明,新系统模型精度良好,测量误差为0.107 mm。采用该模型和标定方法可以克服传统方法系统模型的局限性,最大限度减少误差源并提高抗干扰性。     

温度扰动下CuCl2/DMF溶液的二维相关拉曼光谱分析

溶液的光谱研究一直受到化学工作者的关注,但大多研究是以一维光谱技术为主,存在分辨率低,误差较大,重叠峰难以分辨等诸多弊端,无法清晰地给出需要的信息。二维光谱通过对外部扰动下的动态光谱进行相关分析计算,从而得到光谱强度的整体变化信息,显著提高一维光谱的分辨率以及重叠峰的分离度。在判断特定外扰下不同官能团的响应次序以及研究分子间、分子内的弱相互作用上具有独特优势。采用二维相关拉曼光谱和理论计算相结合,对溶液内微观团簇及其变化进行了研究。利用显微共焦激光拉曼光谱仪对目标溶液(纯DMF与0.84 mol·L-1的CuCl₂/DMF溶液)进行了升温实验。结果发现在C-N键伸缩振动谱带范围内,由于CuCl₂的加入,特征峰强度整体大幅下降,峰宽变大,在1 115 cm-1有新峰产生,随温度升高,伸缩振动峰强度逐渐下降,峰形变缓。为了获得C-N键振动内各特征峰随温度的变化情况,采用移动窗口二维拉曼(MW2D Raman)光谱技术,对光谱数据进行分析。结果表明溶液内不同类别的微观团簇对温度的敏锐程度不同,随温度升高,它们之间存在相互转化,且变化速度不同。为了获取溶液内各微观团簇运动的实质,以温度为外扰,采用二维拉曼(2D Raman)光谱对目标溶液进行分析,通过对二维光谱中特征峰进行归属和变化次序判断,发现金属Cu2+的加入,使得溶液体系变得更加复杂,除存在原溶剂内所含的团簇构型,还存在与Cu2+发生溶剂化的团簇构型,它们之间存在着一定的相互转化。利用密度泛函理论对溶液中可能存在的团簇构型进行结构优化和热力学计算,结果证实了Cu2+与DMF存在相互作用,且由此产生的团簇构型[Cu(DMF)_n]2+(n=1~6)的稳定性随n的增大逐渐变差,进一步验证了二维相关光谱分析的可行性与正确性。     

Microwave solid phase synthesis, characterization, and antimicrobial activity of 3,5-diiodo-salicylalidene-glycine-cobalt(II)

One mononuclear complex, C₉H₇I₂NO₄Co(II) (I) with 3,5-diiodo-salicylalidene, glycine and Co(CH₃COO)₂ · 4H₂O were microwave solid synthesized. The complex was characterized by X-ray crystallography, UV, IR, ESI-MS, and elemental analyses. In addition, further investigation revealed that the central cobalt(II) atom in complex is five-coordinated by one nitrogen atom and four oxygen atoms. The complex was assayed for antibacterial (B. subtilis, S. aureus, S. faecalis, P. aeruginosa, E. coli, and E. cloacae) activities by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl trtrazolium bromide) method. Complex I showed favorable antimicrobial activity with MICs of 3.125, 6.25, 6.25, 6.25, 3.125, and 6.25 μg/mL against B. subtilis, S. aureus, S. faecalis, P. aeruginosa, E. coli, and E. cloacae, respectively.     

Selective aerobic oxidation of sulfides to sulfoxides catalyzed by coenzyme NAD models

Coenzyme NAD⁺ models can be applied in the photooxygenation of sulfides to sulfoxides as organocatalysts at room temperature. A series of sulfoxides are synthesized easily with this protocol and the possible mechanism is discussed. This procedure provides a reliable approach to the clean production of useful sulfoxides in synthetic chemistry.     

A facile strategy to modify TiO2 nanoparticles via surface‐initiated ATRP of styrene

A core‐shell hybrid nanocomposites, possessing a hard core of nano titanium dioxide (n‐TiO₂) and a soft shell of brushlike polystyrene (PS), were successfully prepared by surface‐initiated atom transfer radical polymerization (ATRP) at 90 °C in anisole solution using CuBr/PMDETA as the catalyst, in the presence of sacrificial initiator. FTIR, ¹H NMR, XPS, TEM, SEM, TGA, and DSC were used to determine the chemical structure, morphology, thermal properties, and the grafted PS quantities of the resulting products. TEM images of the samples provided direct evidence for the formation of a core‐shell structure. The thermal stabilities of the grafted polymers were dramatically elevated relative to that of pristine PS according to TGA results. DSC results demonstrated that the TiO₂‐PS nanocomposites exhibited higher glass transition temperature (T_g) compared with pristine PS. The molecular weights of the free polymers formed by sacrificial initiator, which were similar to that of surface‐attached polymers were measured by GPC instrument which showed that the molecular weights of PS were well controlled with a relatively narrow polydispersity index (PDI < 1.2). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1782–1790, 2010     

变频控制直接膨胀式太阳能热泵的数值模拟

文中通过对变频控制直接膨胀式太阳能热泵的数值模拟,指出PV/T- SAHP系统实现变频控制从而解决太阳能热泵集热器面积与压缩机的容量不匹配的关键问题是找到系统集热/蒸发器的MSS线.为变工况下太阳能热泵系统的研究提供参考.     

Onion-like graphitic nanoshell structured Fe–N/C nanofibers derived from electrospinning for oxygen reduction reaction in acid media

Hollow onion-like graphitic nanoshell structured Fe–N/C nanofiber (Fe–N/CNF) catalyst with porous morphology was prepared by heat treating as-spun polyacrylonitrile/ferrous oxalate composite nanofibers in ammonia atmosphere for the first time. These porous electrocatalyst showed both excellent catalytic activity for oxygen reduction reaction (ORR) and much better stability than commercial Pt/C catalyst in acid solution. The Fe–N/CNF catalysts developed here could be easily fabricated on a large scale and show high potential in proton exchange membrane fuel cells (PEMFCs).