喹乙醇的合成

喹乙醇的合成张维汉，李瑞声，李开颜，邓一军，谭桂利（中山大学化学系，广州，５１０２７５）关键词：喹乙醇，合成，相转移催化使用含有饲料添加剂的混合饲料，既节省粮食，又能提高畜牧产品的质量，因此发展高效无毒的多功能饲料添加剂很有意义。喹乙醇（Ｏｌａｑｕｉ...     

福州陶江中国淡水蛏Novaculina chinensis生殖周期的研究

采用活体性腺观察和组织切片法对福建闵候尚干陶江中国淡水蛏的生殖腺进行了初步研究,淡水蛏的性腺发育分为５期,增殖期,生长期,成熟期,排放期和休止期,一年只有一个繁殖周期,繁殖期为３月下旬至４月,雌雄异体,有雄性早熟现象,较晚期的卵母细胞和成熟卵子有双质核仁现象。     

动物血液学的比较研究 Ⅱ．几种脊椎动物的血象、血清蛋白和血液流变学的观察

本文报导了虎纹蛙、黑眶蟾蜍的血象、血清蛋白，中国雨蛙的白细胞分类计数和罗非鱼、家鸽、家兔的血液流变学的研究结果，为比较生理学研究提供基础资料．     

Weingarten rotation surfaces in 3-dimensional de Sitter space

In the 3-dimensional de Sitter Space , a surface is said to be a spherical (resp. hyperbolic or parabolic) rotation surface, if it is a orbit of a regular curve under the action of the orthogonal transformations of the 4-dimensional Minkowski space which leave a timelike (resp. spacelike or degenerate) plane pointwise fixed. In this paper, we give all spacelike and timelike Weingarten rotation surfaces in .     

约束Fractional Tikhonov正则化的模迭代方法

反问题是现在数学物理研究中的一个热点问题,而反问题求解面临的一个本质性困难是不适定性。求解不适定问题的普遍方法是:用与原不适定问题相“邻近”的适定问题的解去逼近原问题的解,这种方法称为正则化方法.如何建立有效的正则化方法是反问题领域中不适定问题研究的重要内容.当前,最为流行的正则化方法有基于变分原理的Tikhonov正则化及其改进方法,此类方法是求解不适定问题的较为有效的方法,在各类反问题的研究中被广泛采用,并得到深入研究.     

AuPt Bipyramid Nanoframes as Multifunctional Platforms for In Situ Monitoring of the Reduction of Nitrobenzene and Enhanced Electrocatalytic Methanol Oxidation

Multifunctional metal nanostructures with a hollow feature, especially for nanoframes, are highly attractive owing to their high surface-to-volume ratios. However, pre-grown metal nanocrystals are always involved during the preparation procedure, and a synthetic strategy without the use of a pre-grown template is still a challenge. In this article, a template-free strategy is reported for the preparation of novel AuPt alloy nanoframes through simply mixing HAuCl₄ and H₂PtCl₆ under mild conditions. The alloy nanostructures show a bipyramid-frame hollow architecture with the existence of only the ten ridges and absence of their side faces. This is the first report of bipyramid-like nanoframes and a template-free method under mild conditions. This configuration merges the plasmonic features of Au and highly active catalytic sites of Pt in a single nanostructure, making it an ideal multifunctional platform for catalyzing and monitoring the catalytic reaction in real time. The superior catalytic activity is demonstrated by using the reduction of nitrobenzene to the corresponding aminobenzene as a model reaction. More importantly, the AuPt nanoframes can track the reduction process on the basis of the SERS signals of the reactants, intermediates, and products, which helps to reveal the reaction mechanism. In addition, the AuPt nanoframes show much higher electrocatalytic properties toward the methanol oxidation reaction than commercial Pt/C electrocatalysts.     

烧结型多孔表面管强化沸腾传热的研究

在前人研究的基础上,本文根据沸腾换热、多孔物质内传热传质及毛细管中两相流的理论及实验,提出了烧型多孔表面沸腾换热的改进模型,再据此而得到新的烧结型多孔表面泡态沸腾换热关联式,与实验结果比较,偏差在士30%以内。关联式适用于F-11,F-12,F-22,F-113,F-114。