双圆弧齿圆柱蜗杆传动可控修形的研究

本文根据共轭曲面原理及齿轮啮合原理的基本理论,对双圆弧齿圆柱蜗杆传动的可控修形问题进行了研究。从理论推导出修形后蜗杆齿面与原理论蜗杆齿面相切条件及接触点处的曲率修正量方程和齿根修正量方程,从而建立了求解可控修形参数的修形齿面方程组。     

蜗杆减速器的发热过程分析

本文研究了蜗杆减速器的发热和温升变化过程,并引入了蜗杆减速器的发热时间常数的概念。指出现行蜗杆传动热平衡计算公式的局限性,提出了适用于各种工况的蜗杆传动热平衡计算公式。     

用杯形砂轮加工凹凸齿圆柱蜗杆时最小砂轮半径的确定

本文分析了用杯形砂轮加工凹凸齿圆柱蜗杆时,砂轮与蜗杆不发生干涉的条件。根据齿轮啮合原理给出了不发生干涉时,确定最小砂轮半径的公式和方法,并根据计算结果给出了简易方法的近似公式,为实际加工提供了理论依据。本文也适用于凹面齿圆柱蜗杆的加工。     

网络蠕虫与IDS防范

蠕虫的爆发给计算机用户带来巨大的损失,蠕虫的防范工作变得尤为重要。本文从蠕虫和IDS的相关技术出发,简要分析蠕虫爆发时IDS的网络特征,进而提出一个行之有效的蠕虫检测模型结构;最后提出在此领域未来的研究发展方向,为今后的科研工作提出新的研究思路。     

改进的双要素蠕虫传播模型

在对计算机蠕虫的研究中,常常借用传染病传播模型,通过研究双要素蠕虫传播模型,提出了一个改进的蠕虫传播模型,并通过Matlab仿真进行了相关试验,证明该模型可以更好地预测蠕虫传播的规模和速度。     

高速实时的一种邮件蠕虫异常检测模型

提出了一种基于带泄漏的积分触发测量方法的电子邮件蠕虫异常检测方法,用来检测邮件蠕虫在传播过程中的流量异常。根据邮件流量所表现出的明显的日周期特性和周周期特性,首先计算出当前邮件流量和历史邮件流量的最小Hellinger距离,通过带泄漏的积分触发方法把邮件流量的Hellinger积累起来,从而把邮件蠕虫在传播过程中没有明显流量特征的慢速酝酿阶段的异常特征进行积累,达到在其进入快速传播期之前检测出异常的目的。检测过程只需要检查邮件的流量信息,因而适合大规模高速网络的异常检测。     

Study on Nanocrystalline Rare Earth Mg-Based System Hydrogen Storage Alloys with AB3-Type

A sort of rare earth Mg-based system hydrogen storage alloys with AB3-type was prepared by double-roller rapid quenching method. The alloys were nanocrystalline multi-phase structures composed of LaNi3 phase and LaNi5 phase by X-ray diffraction and scanning electron microscopy analyses, and the suitable absorption/desorption plateau was revealed by the measurement of P-C-I curve. Electrochemical studies indicate that the alloys exhibit good electrochemical properties such as high capacity and stable cycle life, and the discharge capacity is 369 mAh·g-1 at 0.2 C (72 mA·g-1), after 460 cycles, the capacity decay was only 19.4% at 2 C (720 mA·g-1).     

平面包络环面蜗杆啮合型面的数据矩阵

研究了平面包络环面蜗杆啮合齿面方程，并探讨建立基于网格矩阵的啮合型面的矩阵模型方法。采用网格划分表面点的矩阵表达模式，建立了基于数据矩阵的啮合型面模型，为实现平面包络环面蜗轮副啮合型面的进一步分析奠定了基础。     

Numerical simulation of a sheet metal extrusion process by using thermal—mechanical coupling EAS FEM

The thermal-mechanical coupling finite element method(FEM) was used to simulate a non-isothermal sheet metal extrusion process.On the basis of the finite plasticity consistent with multiplicative decomposition of the deformation gradient,the enhanced assumed strain(EAS)FEM wasd applied to carry out the numerical simulation.In order to make the computation reliable and avoid hourglass mode in the EAS element under large compressive strains,an alterative form of the original enhanced deformation gradient was employed.In addition,reduced factors were used in the computation of the element local internal parameters and the enhanced part of elemental stiffiness.numerical results show that the hourglass can be avoided in compression region.In the thermal phase,the boundary energy dissipation due to heat convection was taken into account.As an example,a circular steel plate protruded by cylindrical punch was simlated.The step-wise decoupled strategy is adopted to handle coupling between mechanical deformation and the temperature variation.By comparing with the experimental results.the numerical simulation was verified./     

滚锥包络环面蜗杆传动载荷分布与分配研究

在＂滚锥包络环面蜗杆传动的理论研究与参数优化［１］＂和０＂Ｓｔｕｄｙｏｎｔｈｅｒｏｌｌｉｎｇｃｏｎｅｅｎｖｅｌｏｐｉｎｇｈｏｕｒｇｌａｓｓｗｏｒｎｇｅａｒｉｎｇ［２］＂文献的基研、提出了一种求解滚锥包络环面蜗杆传动接触线上载荷分布与齿间载荷分配的方法。编制了计算滚锥包络环面蜗杆传动接触线上载荷分布与齿间载荷分配的计算机程序，对该传动的载荷分布与分配进行了计算研究，并给出了对本文方法正确性的实验验证结果。