浅析英语词汇教学的过程

词汇教学是英语教学的重要组成部分,教师应具备正确的词汇教学理念。本文在词汇的选取、分类,以及学生的学习过程三方面论述了英语词汇教学的基本过程。     

参数曲面的拟自适应三角化

提出了一种参数曲面的拟自适应三角化离散算法。该算法通过对曲面的参数域进行预剖分，以及引入曲面上一点处的“最大绝对法曲率”的概念，采用“分而治之”的方法分片对参数曲面的参数域进行三角形网格剖分。该方法基本上可以像“自适应”方法一样，根据曲面的法曲率变化来控制三角化剖分的密度，生成的三角片数量较少，并且可以避免在三维空间产生狭长的三角形、退化三角形与“裂缝”，运行速度明显比自适应方法快。     

The Processing of Band-Limited Measurements; Filtering Techniques in the Least Squares Context and in the Presence of Data Gaps

This paper discusses the treatment of correlated measurements in the least squares context. We focus on the processing of band-limited measurements and on long time series with a constant sampling interval. Time domain as well as frequency domain approaches were discussed to offer different ways to integrate the filtering process into the optimization scheme as good as possible. The focus was on long equispaced data sets. The application of discrete filters in the space domain makes it possible to decorrelate the observations during data acquisition. This opens the way to a sequential adjustment procedure, where the design matrix is treated row-by-row. Huge systems with millions of observations can be solved by direct or iterative strategies, and both approaches benefit from well-tailored filter techniques. Because of the sequential access the computational effort of this giant task can be easily distributed to a cluster of parallel processors and offers, in addition, the possibility to treat data gaps in a straightforward way. This revised version was published online in August 2006 with corrections to the Cover Date.     

提高微细电解加工精度的研究

对影响微细电解加工精度的因素进行了详细的分析,提出了改善加工精度的方法,如以循环进刀代替直接进刀方式、采用脉冲加工电源、改善阴极的结构设计以及采用非线性电解液等。最后,结合实验对这些方法的可行性与有效性进行了验证。     

“系统工程”辨析

系统工程(Systems Engineering)是成功实现系统的方法,也是应对技术复杂性的有效方法。系统工程从需求出发,综合多种专业技术,通过分析-综合-试验的反复迭代过程,开发出一个满足使用要求、整体性能优化的系统。在国内,对"系统工程"有不同的理解和定义,例如"社会系统工程"、"系统工程学"、"系统工程是工程项目"等概念。航天领域的系统工程(航天系统工程方法)具有如下特点:强调总体设计,遵循研制程序,是反复应用的系统工程过程和定量的方法。     

某型导弹前支脚协调零件加工工艺研究

叙述某型导弹的新型结构－－斜燕尾槽配合的具有高协调要求的镀镍、机加工的工艺方法。改进后的“镀前加工协调尺寸预先补偿法”，已成功应用于某型导弹的批产。在同类协调零件制造过程中，该种方法具有较大的借鉴作用。     

CAPP在减振器上的应用

汽车减振器CAPP系统采用半生成式,对减振器的装配工艺及其零件制造工艺能自动生成,人工干预少,规范减振器产品的工艺设计,提高工艺设计效率。     

列表点曲线数控加工编程研究

提出了加工列表点曲线的两种方法，产开发了列表点曲线拟合的专用的程序、数据处理和后置输出处理的专用程序模块，对数控机床上加工列表点曲一以及使用委切法旬表点曲面提供了一种精确快捷的手段。     

Solar terrestrial effects of two distinct types

The occurrence frequencies or fluxes of most of the solar phenomena show a 11-year cycle like that of sunspots. However, the average characteristics of these phenomena may not show a 11-year cycle. Among the terrestrial parameters, some related directly to the occurrence frequencies of solar phenomena (for example, ionospheric number densities related to solar EUV fluxes which show 11-year cycle like sunspots) show 11-year cycles, including the double-peak structures near sunspot maxima. Other terrestrial parameters related to average characteristics may not show 11-year sunspot cycles. For example, long-term geomagnetic activity (Ap or Dst indices) is related to the average interplanetary solar wind speed V and the total magnetic field B. The average values of V depend not on the occurrence frequency of ICMEs and/or CIRs as such, but on the relative proportion of slow and high-speed events in them. Hence, V values (and Ap values) in any year could be low, normal or high irrespective of the phase of the 11-year cycle, except that during sunspot minimum, V (and Ap) values are also low. However, 2–3 years after the solar minimum (well before sunspot maximum), V values increase, oscillate near a high level for several years, and may even increase further during the declining phase of sunspot activity, due to increased influence of high-speed CIRs (corotating interplanetary regions). Thus, Ap would have no fixed relationship with sunspot activity. If some terrestrial parameter shows a 11-year cycle, chances are that the solar connection is through the occurrence frequencies (and not average characteristics) of some solar parameter.     

降落伞开伞过程正交试验研究

降落伞开伞过程存在的偏差因素可能会导致开伞动压峰值及开伞力峰值出现极大值,从而对回收过程可靠性造成影响.文章以开伞动压峰值及开伞力峰值为试验指标,采用正交试验方法对比分析了不同水平数情况偏差因素对试验指标的影响度大小,得到了试验指标极值及对应的偏差因素取值条件,并分析了忽略系统初始偏航角、初始滚转角、初始角速度等次要偏...