关子二维保面积映象的研究

本文研究了二维保面积映象的稳定周期轨道、同周期分岔、倍周期分岔及Kolm—Jogorov熵,发现周期N轨道的失稳曲线在局部区域互相交错和打结,得到了同周期分岔条件及区分三种同周期分岔类型的解析判据,和倍周期序列分岔率及标度变换因子,对描速映象混沌程度的Kolmogorov熵也进行了计算。     

Optimization of cultural conditions for thermostable β-1, 3-1, 4-glucanase production byBacillus subtilis ZJF-1A5

The optimization of cultural conditions for β-glucanase production byBacillus subtilis ZJF-1A5 was investigated in flask trials. Temperature had great effect on β-glucanase production which maximized at optimal temperature of 37°C and decreased significantly when temperature was over 37°C. Charge quantity affected β-glucanase production significantly. Adding oxygen vector N-dodecane or acetic ether benefited β-glucanase production, but it depended on the concentration and charge quantity. The results of fractional factorial design showed that age and size of inoculum and shaking speed were the key factors affecting β-glucanase production and the cultivation time span to reach the highest β-glucanase activity. The optimal cultural conditions for β-glucanase production obtained with CCD were as follows: inoculum age and size (16 h, 3.82% (v/v)), shaking speed 210 r/min, charge quantity of 30 mL in 250 mL flask and initial pH 7.0, cultured at 37°C for 50 h. Repeated experimental results accorded with those predicted by a second-order polynomial model. The amount of β-glucanase, α-amylase and neutral protease produced byB subtilis ZJF-1A5 was associated partially with cell growth. Those three enzymes' activities increased following the cell growth and increased significantly when cells entered the stationary phase. Project (No. B0608) supported by the National Natural Science Foundation of China and a grant (2001121B25) from Hangzhou Science and Technology Development Project of Zhejiang Province, China     

打破表层结构译出原文真意--评析夏济安译作《霍桑论》

从打破原文表层结构的角度,通过评析夏济安译作<霍桑论>,透视译文中改变语序以符合中文习惯;利用文章剩余信息,添"枝"加"叶";转换词类,化顺为逆或化逆为顺;巧用四字句;化整为零等翻译技巧.     

非线性系统变结构鲁棒控制器的设计及其在电力系统中的应用

提出了一种非线性系统变结构鲁棒控制器设计方法，对切换平面的设计步骤和控制作用的求取作了详细论述，并给出了在电力系统中的应用实例及仿真结果．     

Intersections of two offset parametric surfaces based on topology analysis

Conventional methods for solving intersections between two offset parametric surfaces often include iteratively using computationally expensive SSI (surface/surface intersections) algorithm. In addition, these methods ignore the relations between the intersection curves of parametric surfaces with different offset distances. The algorithm presented in this paper, makes full use of the topological relations between different intersection loops and calculates intersection loops with the help of previously calculated intersection loops. It first pre-processes two parametric surfaces to obtain the characteristic points, called topology transition points (TTPs), which can help in the subsequent finding of the topologies of the intersection curves. Then these points are categorized into several distinct groups, and we can determine the calculation strategy for searching initial points by analyzing the properties of these TTPs on the surfaces. Hence, all intersection curves can be marched from initial points by the tracing algorithm. The proposed algorithm could calculate intersection curves robustly and effectively, and has been tested to be capable of overcoming the degenerate conditions such as loop and singularities leaking that occur frequently in conventional algorithms. Project supported by the National Research Foundation for the Doctoral Program (No. 2000033554) of Higher Education of China and the Natural Science Foundation of Zhejiang Province, China (No. 6001107)     

COMPUTER SIMULATION FOR ELECTRICALLY DRIVEN MOTION OF FLUID

In this paper,an equation system of electrohydrodynamics(EHD)based onthe fluid motion equations is discussed.Emphasis is put on the effects of electrical forceand surface tension upon the fluid motion.The Marker and Cell method is used to set up acomputational simulation program of electrically driven motion of fluid.With the help ofthe program,a cylindrical fluid under the influences of electrical field and surface tensionhas been calculated.The result is in good agreement with the experimental observation.     

Influence of Different Surface Treatments of H13 Hot Work Die Steel on Its Thermal Fatigue Behaviors

Thermal fatigue checking is general failure of hot work die steels,which is relative with the structures and properties of the steels and the stress alternated during the employment.The Uddeholm test method on thermal fatigue is used to compare the behaviors of different samples,which are treated with plasma nitriding 、plasma sulfur-carbon-nitriding、boronizing or not treated.The results show that the nitriding improves the thermal fatigue property of the tool steel,while the plasma sulfur-carbon-nitriding and the boronizing impair the property.The mechanisms are induced as follows .By increasing the hardness and changing the stress distribution in the surface layer,surface treatment can decrease the plastic deformation and the temsile stress during the cycling.Therefore,the generation and growth of the cracks are restrained.On the other hand,as results of surface treating,in the surface layer the toughness declines and the expanding coefficient ascendes;the latter change caused the strengthening of the tensile and compressive stress during the cycling.Thus the resistance to thermal fatigue is weakened.Whether or not the surface treatment is favor to thermal fatigue of tool steels relies on which factor is dominant.     

挠率线的几个性质

给出了挠率线的一些性质.推广了以往文献中的结论.     

浅析物理实验中的视差问题

在物理量的测量中,正确的瞄准和读数是保证测量数据准确可靠的关键。而视差的影响是主要的误差因素。本文就视差的定义、产生视差的原因以及视差的影响作了阐述和分析。     

二氧化钛光催化剂的表面修饰

系统介绍了二氧化钛光催化剂表面修饰的类型、机理，效果、以及研究现状和发展方向。