石墨烯负载高活性Pd催化剂对乙醇的电催化氧化

以石墨粉为原料, 采用Hummers法液相氧化合成了氧化石墨(GO), 然后用化学一步还原制得石墨烯负载钯催化剂. X射线衍射(XRD)、透射电镜(TEM)表征表明, Pd在石墨烯载体上有较好的分散度, 粒径为3-5 nm. 电化学活性面积(EASA)、循环伏安(CV)、计时电流(CA)和计时电位(CP)等电化学测试表明, 与传统Pd/Vulcan XC-72相比, Pd/石墨烯催化剂对碱性介质中乙醇电催化氧化的催化活性有了很大的提高.     

牡蛎中脂肪酸在储藏过程中的稳定性

用超临界流体萃取 (SFE)及GC MS分析了新冷冻干燥及保存 1 5d ,30d ,45d ,60d ,75d ,90d后的鲜牡蛎粉中的 2 3种脂肪酸组分的质量分数。发现在存放过程中牡蛎脂肪酸的稳定性与其不饱和度有关 ;不饱和度越高 ,脂肪酸越易被氧化 ,其中多不饱和脂肪酸的氧化是逐渐进行的 ,没有特定的稳定期。放置 90d后 ,牡蛎脂肪酸中脑黄金EPA的质量分数由原来的 1 6 94%降至 5 43% ,DHA由 9 2 5%降至 2 86%。     

Internal Conversion with N,N-substituted 1-aminonaphthalenes:Photophysics and Applications

The solvent polarity dependence of the fluorescence quantum yield and lifetime of 1-dimethylaminonaphthalene (DMAN) was fund different from that of normal case in that the two parameters increase with increasing solvent polarity, in spite of the fact that the emissive state of DMAN was also of ICT character. Steady state and time-resolved fluorescence studies have currently indicated that a thermally activated internal conversion (IC) occurred with DMAN^[1,2]. The IC was assumed to be the consequence, of the vibronic coupling of the emissive S₁ state and S₂ state with the activation energy of the IC process depending on the energy gap between S₁ and S₂ states. It was hence put, forward that with increasing solvent, polarity the energy of the S₁ state would be lowered more than that of the S₂ state, leading to higher energy gap between the S₁ and S₂ states and therefore suppressed IC. As a consequence, increased fluorescence quantum yield and lengthened lifetime were observed.     

两步法制备多孔硅及其表征I:恒电流法(英文)

本工作通过采用电化学极 -化学氧化两步法在 1:1氢氟酸和乙醇溶液中制备出孔径约为 1～ 2 μm ,厚度大经为 6～ 10 μm的多孔硅样品 .首先将 0 .0 3A/cm2 的恒电流施加到p( 10 0 )硅片一段时间 ,然后将该硅片浸到 2 0 %的硝酸溶液中氧化一段时间 .通过此方法获得的多孔硅结构再进一步用扫描电子显微镜和拉曼光谱仪进行表面形貌和光学性质的考察 .所有制备出的多孔硅结构均有光致发光现象 .老化的多孔硅样品 (在干燥器放置一年 )的光致发光谱峰强度明显增强 ,但分别经过苯乙烯和十六碳烯 ( 1)两种有机溶剂处理 1h后的老化多孔硅样品的光致发光强度却没有显著改变 .     

过渡区核87Zr的高自旋态研究

通过束流能量为118MeV的⁵⁹Co(³²S,3pn)⁸⁷Zr熔合蒸发反应,用在束r谱学方法研究了⁸⁷Zr的高自旋态.利用7台反康普顿谱仪组成的探测阵列进行r–r符合测量,并确定部分r射线的DCO值,在此基础上建立了自旋直到(37/2⁺)和(43/2^－)的能级纲图.观测到了多条新的能级.与相邻的同中子异荷素的比较表明,中子对核结构性质的影响远大于质子的贡献.随着质子数的增加,第一交叉频率呈减小的趋势.     

含有分层损伤的复合材料加筋层合板的屈曲性态研究

基于Ｍｉｎｄｉｎ假定推导了考虑剪切的复合材料加筋层板的有限元列式,并在此基础上计算出筋间基板含嵌入分层以及筋与基板连接处含穿透分层的加筋层合板在受压缩载荷情况下的屈曲模式和临界力。本文所给出的有限元方法及结论对从事复合材料结构设计的工程人员具有参考价值。     

Double compactons in the Olver–Rosenau equation

It is showed that the fully nonlinear evolution equations of Olver and Rosenau can be reduced to Hamiltonian form by transformation of variables. The resulting Hamiltonian equations are treated by the dynamical systems theory and a phase-space analysis of their singular points is presented. The results of this study demonstrate that the equations can support double compactons. The new Olver–Rosenau compactons are different from the well-known Rosenau–Hyman compacton and Cooper–Shepard–Sodano compacton, because they are induced by a singular elliptic instead of singular straight line on phase-space.     

New Zincophosphite with Infinite One-dimensional [Zn(HPO_3)(H_2PO_3)]~– Chains: Synthesis, Characterizations and Spectral Properties

With dimethylamine as a template, a new one-dimensional zincophosphite (C2H8N)·[Zn(HPO3)(H2PO3)] was prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction, FTIR spectrametry, elemental analysis, powder X-ray diffraction, and thermogravimetric analysis. The compound crystallized in the Monoclinic space group P2(1)/c, with cell parameters, a=0.78410(9) nm, b=1.54744(2) nm, c=0.81418(1) nm, β=105.8150(1)°, V=0.95049(2) nm3 and Z=4. The connectivity of the ZnO4 tetrahedron...