Financial market model based on self-organized percolation

Financial markets are typical complex systems in which the large-scale dynamical properties depend on the evolution of a large number of nonlinear-coupled subsys-tems. The efficient market hypothesis (EMH) based on rational expectation assumption (REA) considers the price of financial markets as random walk, thus the return dis-tribution obeys Gaussian form. However, the EMH suffers the impugnation on REA and the challenge of actual fi-nancial data that the real-life markets are of return…     

2002中国十六大科技成就

中国科学院学部办公室、中国工程院学部工作部等联合主办,宋健、路甬祥、徐匡迪等568位中国科学院院士和中国工程院院士投票评选的2002年中国十大科技进展26日在京揭晓.它们分别是:①我国科学家率先绘制出水稻基因组精细图和水稻第四号染色体精确测序图:②"神舟三号"、"神舟四号"飞船发射成功;③我国发现首个世界级大气田探明储量6000多亿立方米;④三峡工程导流明渠截流成功:⑤我国第三代移动通信系统研制成功;⑥我国已初步掌握当代CPU关键设计制造技术;⑦浙江农科院培育出世界上含油量最高的油菜新品系:⑧"神光二号"巨型激光器研制成功:⑨北大医学部科学家初步揭开人类细胞衰老之谜:⑩联想推出万亿次超级计算机.     

素描与素描教学

素描作为艺术院校的基础课程，在传统教学基础上，加强其绘画语言的训练，培养学生造型意识和心、手、眼的协调能力具有重要意义。     

Fuzzy Entropy Based Combined Learning Algorithm for Neural Networks

ＦｕｚｚｙＥｎｔｒｏｐｙＢａｓｅｄＣｏｍｂｉｎｅｄＬｅａｒｎｉｎｇＡｌｇｏｒｉｔｈｍｆｏｒＮｅｕｒａｌＮｅｔｗｏｒｋｓ￥ＭｉｎＹａｏ（Ｄｅｐｔ．ｏｆＣｏｍｐｕｔｅｒＳｃｉｅｎｃｅ，ＨａｎｇｚｈｏｕＵｎｉｖｅｒｓｉｔｙ，Ｈａｎｇｚｈｏｕ３１００２８，Ｐ...     

微机控制PID算法的选择及参数的整定

本文从实用的角度讨论了PID微机控制算法的选择,参数的整定和程序的编制。     

A solution of spatial query processing and query optimization for spatial databases

Recently,attention has been focused on spatial query language which is used to query spatial databases. A design of spatial query language has been presented in this paper by extending the standard relational database query language SQL. It recognizes the significantly different requirements of spatial data handling and overcomes the inherent problems of the application of conventional database query languages. This design is based on an extended spatial data model,including the spatial data types and the spatial operators on them. The processing and optimization of spatial queries have also been discussed in this design. In the end,an implementation of this design is given in a spatial query subsystem.     

Effects of baria on propane oxidation activity of Pd/Al2O3 catalyst: Pd–BaO interactio n and reaction routes

The BaO-modified Pd/Al2O3exhibits much better catalytic activity than Pd/Al2O3for C3H8 oxidation both before and after the hydrothermal aging treatment. Further studies ascribe its good activity to the influence of BaO species on the physicochemical characteristics of the catalyst and the reaction routes. Firstly, the BaO species inhibits the phase transformation of alumina, resulting in higher surface area of the catalysts and hereby a better dispersion of Pd. Secondly, the basic nature and electron-withdrawing effect of barium oxide maintain palladium at high oxidation state, which leads to a higher PdO content on surface of the BaO-modified catalyst. Finally, the formation/decomposition of carbonate/bicarbonate species can be promoted by the addition of BaO, which provide extra reaction routes and are important for the deep oxidation of C3H8.     

Nonclassical Plane-crystallographic Groups and Their Applications IV

Eight kinds of nonclasslcal periodic lattices with locally 8-fold rotational symmetries are introduced.They can be described via nonclassical Planc-crystallographic groups. The periodic lattices may be interpreted by the projections on the plane of the corresponding unit cells consisting of embedding polyhedrons, respectively. The Fourier-transform patterns of the Periodic lattices have striking approximate "8-fold rotational symmetries", some of which are similar to those displaying in the electrton-diffraction patterns of so-called quasicrystals.     

荷电气—液两相同轴圆射流的LDV研究

静电喷雾技术在许多领域得到广泛应用,但对荷电气两相流的理论研究尚不深入笔者通过采用二维激光多普勒测速系统（ Ｌ Ｄ Ｖ） 对荷电气—液两相同轴圆射流进行了实验研究,就电场作用下液滴直径的分布、荷电气液两相流的速度分布进行了分析,并给出了相间运动规律,为荷电两相湍流的深入研究提供了一定的试验依据