多时滞Lotka-Volterra互惠系统周期正解的存在性

用重合度理论研究具时滞非自治Lotka-Volterra互惠系统，获得了周期正解的存在性，推广了Gopalsamy及He(1997)的结果。     

Experimental Study about Activated Water Generated by the Electro—hydraulic Impulse Strengthening the Mechanical Performance of Concrete

On the basis of a great number of experiments, it is proved that the strength of concrete is improved greatly when it is mixed with activated water produced by the electro-hydraulic impulse.With the proper parameters, the compression strength of concrete can be increased by 45% .The reason for improvement of concrete strength by using activated water is discussed from the aspect of the structure of molecule.     

医院空调设计的几点体会

空调系统应用于普通房间可能引起空调病 ,应用于医院时此问题将更为突出 ,本文对此类建筑在空调系统设计中应重视的有关问题进行了初步探讨     

纳米超晶格热电材料的研究进展

随着热电材料制备技术和性能研究的发展，纳米超晶格热电薄膜已受到人们的关注，简要介绍了有关纳米超晶格热电材料的结构、热电机理及制作技术，并指出了存在的问题和可能的发展方向。     

利用相对坐标轻松完成网格袋布局

网格袋布局管理器是java布局中最有用、最灵活、最复杂、最难掌握的一种布局管理器,实际上,如果我们明白了在布局时它利用了单元格相对坐标定位这一点,以及各个约束条件在布局中的作用,网格袋布局也会变得很轻松。     

内管注水泥固井工具的研究与分析

内管注水泥技术是针对大尺寸套管和表层套管固井的特点及特殊要求而采用的一种固井技术，具有省时、替量少等特点，在现场得到大量推广应用。内管注水泥器是内管固井技术的关键工具，其性能好坏直接影响到固井质量。对各种内管注水泥固井工具的结构及特点分别进行了分析研究，并就其发展方向提出建议。     

铝电解槽磁流体稳定性有限元分析

本文采用有限元法求解分层磁流体小扰动方程系统特征值，研究铝电解槽稳定性。研究结果表明，在没有电磁力时，铝液表面波动（内波）是稳定的。存在电磁力时，它会激发铝液表面波动的某些低频长波分量不稳定性，高频短波不受影响。被激发的不稳定波动频率和扰动增长率与电流密度，磁感应强度垂直分量，铝电解槽长宽比，电解质和铝液的密度差，厚度等因素密切相关。减少电流密度，磁感应强度，增加电极距离和铝液厚度可以提高铝电解槽的稳定性。这对铝电解槽优化设计和在线控制有重要意义。     

西北江三角洲来水来沙的非线性分形特征

根据西、北江干流高要、石角及西北江三角洲网河区顶点马口、三水四个水文站的流量和含沙量资料 ,应用非线性分形原理的R S方法 ,计算西北江干流及西北江网河区顶点四个水文站的流量、含沙量的赫斯特数H和分形维数D ;探讨西、北江干流来水来沙的分形特征及西北江三角洲的分水分沙规律。结果表明 ,流量的分维数略大于含沙量的分维数 ,三水站流量及含沙量的分维数与其上游的石角站流量、含沙量的分维数相差较大 ,与思贤的分水分沙造成西北江的水沙交换有关     

Variations in Spectral Slope in Lake Taihu,a Large Subtropical Shallow Lake in China

Spectral slope (S), describing the exponential decrease of the absorption spectrum over a given wavelength range, is an important parameter in the study of of chromophoric dissolved organic matter (CDOM) dynamics, and also an essential input parameter in remote sensing models. Furthermore, S is often used as a proxy for CDOM composition, including the ratio of fulvic to humic acids and molecular weight. The relative broad range in S values reported in the literature can be explained by the different spectral ranges and fitting methods used. A single exponential model is used to fit the S values for 17 investigations involving 458 samples in Lake Taihu from January to October in 2004. The average S value was 15.18 ± 1.39 μm⁻¹ for the range of 280–500 nm, which fell within the range reported in the literature. The frequency distribution of S value basically obeyed a normal distribution. Significant differences in S values between summer and other seasons showed that phytoplankton degradation was one of the important sources of CDOM in summer, whereas CDOM mainly came from the river input in other seasons. Furthermore, the estimated S value decreased with increasing wavelength range used in regression. The maximum and minimum values derived from the regression were 17.89 ± 1.25 μm⁻¹ and 13.62 ± 2.11 μm⁻¹ for the wavelength ranges of 280–380 nm and 400–500 nm, respectively, a decrease of 23.9%. S values significantly decreased with the increase of CDOM absorption coefficients. CDOM absorption coefficients could be more appropriately estimated from exponential model introducing the variation of S with absorption coefficients, making them useful for a remote sensing bio-optical model of Lake Taihu. DOC-specific absorption coefficient a*(λ) and the parameter M describing molecular size of the humic molecules could also be used as a proxy for the sources and types of CDOM. A general relationship was found between S and a*(λ), and M values. S increased with the decrease of DOC-specific absorption coefficient and the increase of M corresponding to the decrease of molecular weight.