Study on reproductive endocrinology of human placenta (III)--Hormonal regulation of progesterone production by trophoblast tissue of first trimester.

The effect of hormones on progesterone secretion by 6-8 week human trophoblast tissue cultured in serum-free medium has been investigated. GnRH at low concentration (10(-10)-10(-8) mol/L) stimulated progesterone secretion, while high dose (10(-6)-10(-5) mol/L) produced inhibitory effect. The progesterone secretion could be significantly decreased by addition of anti-hCG antiserum or monoclonal anti-hCG IgG in a dose- and time-dependent manner. Various concentrations of TRH, PGE2, PGF2 alpha, testosterone and estradiol were found to be ineffective. These data indicate clearly that progesterone production by human trophoblast tissue at early gestation stage is under the modulation of GnRH and hCG.     

Expert systems for HPLC in biochemistry—The knowledge base for selection of HPLC column system in the separation of amino acids,peptides and proteins

The strategy of expert system for high performance liquid chromatography was discussed, the attentions are mainly placed on the knowledge base for selection of column system, separation modes and detection modes in the analysis of amino acids, peptides and proteins.     

Erosion and Sediment Production in Small Watershed in Purple Hilly Areas and Prevention Techniques

Purple Soil distributes extensively and mainly in China. Because of abundant easily weatherable parent rocks/materials and unstable soil structure, and also influenced by parent materials, usage systems, and slope gradients, erosion and sediment production of purple soils are very severe with main fashions of water erosion and gravitational erosion. Basing on observed data in small watersheds, rainfall erosivity,vegetation coverage, previous soil water content, flow and relating factors such as climate, topograph of small watershed,land usage, and soil kinds are all the influence factors of erosion and erodibility of purple soil as well as sediment production and transport in small watershed of purple hilly areas.The effective technological countermeasures of ecosystem restoration, agricultural tillage for water conservation and erosion prevention, agriculture project, and soil changing for fertility and anti-erosion were provided.     

On new forms of motive differential equations of a mechanical system relative to non-inertial frame

Based on D'Alembert's principle of a mechanical system relative to non-inertial frame and by introducing the concept of the generalized inertial potential, new forms of differential equations of motion of a mechanical system with holonomic and the non-holonomic constraints relative to the non-inertial frame are obtained. The merits and demerits between our method and the Newtonian dynamic method as well as the analytic dynamic method are discussed comparatively. Finally, two examples are given to illustrate the application of the motive differential equations in the new forms.     

政治学视野中的依法治国与权力制约

近年来“依法治国”的口号响遍神州大地，这在某种程度上反映出中国对法治的重视和需求。然而，口号并不等于实际，法治口号与法治实践之间尚存较大差距，尽管法治口号震天响．公共权力腐败问题仍十分严重，如何防止滥用公共权力和遏制权力腐败，成为当代民主与法治的重大课题，因此要着重从权力制约的价值基础，权力制约在依法治国中的意义及完善我国法治的权力制约机制三方面进行探讨。     

On the persistence of elliptic lower-dimensional tori in Hamiltonian systems under the first Melnikov condition and Rüssmann’s non-degeneracy condition

In this paper we formulate a theorem on the persistence of elliptic lower-dimensional invariant tori for nearly integrable analytic Hamiltonian systems under the first Melnikov condition and Rüssmann’s non-degeneracy condition, and give the measure estimates of parameters for the non-resonance conditions under Rüssmann’s non-degeneracy condition, which is essential for the proof of our result.     

多媒体教学手段在天文教育中的应用--天文教学系列软件"探索宇宙"简介

结合中国目前天文学教育的现状和我系开展基础天文学教学的体会,对天文学教学中如何利用多媒体的手段进行了论述,并重点介绍了天文系列多媒体教学软件<探索宇宙>的特点和主要内容.     

The prediction of the peak width at half height in HPLC

The prediction of the peak width at half height is an important aspect in the optimization of the chromatographic operating conditions. In this paper, a linear relationship, between the peak widths at half height and the retention values with various isocratic elution is observed. In gradient elution, however, the relationship between the peak widths at half height and the so-called invented retention values that correspond to the mobile phase composition by eluting the solute from the column end is developed. We believe that there is almost the same band width at half height inside the column (in unit of length) for different solutes. The peak width at half height in the chromatogram (in unit of time) is mainly determined by the capacity factor of the solute when it is eluted from the column end. The larger the capacity factor of a solute eluted from the column end, the more slowly will be the solute eluted from the column end and the wider will be the peak width at half height. It is possible to predict the peak width at half height in various isocratic and gradient elutions by using this linear relationship.     

Fibonacci,Lucas序列与高阶Bernoulli多项式

本文给出了包含Ｆｉｂｏｎａｃｃｉ序列｛Ｆｎ｝、Ｌｕｃａｓ序列｛Ｌｎ｝及高阶Ｂｅｒｎｏｕｌｌｉ多项式Ｂｎ（Ｋ）（ｘ）的一些恒等式。