简述近期我国硬质合金工业发展趋势

介绍了2005年我国硬质合金行业基本情况,分析了近期行业发展趋势。     

CAL delivery selection criteria and authoring systems

Abstract  In the past, authoring systems have been used to generate computer-assisted learning materials that have often followed the rather restrictive programmed learning format. A number of innovative ways of using recently developed systems to develop CAL packages that include a wider range of learning activities (access to data bases, simulations, interactive video, etc.) are described. Analogous to the concept of a media selection model, a computer delivery mode selection model is presented as an aid to decision making for designers. This increase in flexibility should broaden the applicability of computerassisted learning (CAL) to a wider range of educational objectives and raise the level of the cognitive emphasis in learning packages, as well as facilitate the implementation of visually appealing materials. The paper also implies a standard of acceptability for authoring systems.     

Enhanced Oil Recovery: The Synthesis of Anthraquinone [1, 2-C] Alkylisoxazole

Anthraquinone [1, 2-C] methylisoxazole is synthesized from 2-ethylanthraquinone through nitration and treating with oleum. The different methods of 2-ethylanthraquinone nitrated were discussed. The optimum conditions were determined. The structure of the product was confirmed by MS and ¹H NMR.     

Influence of thermal boundary conditions on natural convection in a square enclosure partially heated from below

Natural convection in air-filled 2D square enclosure heated with a constant source from below and cooled from above is studied numerically for a variety of thermal boundary conditions at the top and sidewalls. Simulations are performed for two kinds of lengths of the heated source, i.e., a small and a large source corresponding to 20% and 80% of the total length of the bottom wall, respectively. The Rayleigh number varied from 10³ to 10⁷. Results are presented in the form of streamline and isotherm plots as well as the variation of the Nusselt number and maximum temperature at the heat source surface. Comparisons among the different thermal configurations considered are reported.     

机械合金化Fe─B非晶合金及纳米合金的形成

在适当条件下机械合金化可以形成急冷法难以得到的单一Ｆｅ６０Ｂ４０非晶合金，而在其他成分内形成亚稳纳米合金。在众多的球磨条件中，球磨机的转速是控制合金化的重要因素，空气中的氧对小颗粒界面产生了强烈的污染作用，从而抑制了原子的相互扩散，难以形成单一的非晶产物。不同球磨条件下的产物含有的非晶相的晶化温度比单一非晶相合金的晶化温度稍高，并且与球磨条件以及成分的关系不大。     

万顷沙西十三涌油轮码头模型试验研究

华隆公司拟在万顷沙西十二涌与十三涌之间兴十三涌３０００Ｔ级油轮港口码头。本文分析了该河段水文泥沙的特性、河道演变趋势及河段稳定性，通过物理模型试验研究及对航道、港池的回淤计算分析，预测工程建成后引起局部水流流态的变化，对水道泄洪、潮排、潮灌的影响，以及港池、航道建成后的泥沙淤积情况。     

A new approach of formation navigation derived from multi-robots cooperative online FastSLAM

A new formation navigation approach derived from multi-robots cooperative online FastSLAM is proposed. In this approach,the leader and follower robots are defined.The posteriori estimation of the leader robot state is treated as a relative reference for all follower robots to correct their state priori estimations.The control volume of individual follower will be achieved from the results of the corrected estimation.All robots are observed as landmarks with known associations by the others and are considered in their landmarks updating.By the method,the errors of the robot posterior estimations are reduced and the formation is well kept.The simulation and physical experiment results show that the multi-robots relative localization accuracy is improved and the formation navigation control is more stable and efficient than normal leader-following strategy.The algorithm is easy in implementation.     

基于GPS/DR的GPS滞后时间自适应检测算法

针对GPS输出信息的随机延迟特性,基于航位推算(DR)系统惯性器件的实时性与短时高精度,提出了航向差和速度自适应GPS滞后时间检测方法,在此基础上,对GPS和DR数据进行数据对准,提出了自适应GPS滞后时间处理算法。在GPS/DR实际系统中的应用结果表明,本算法能够准确检测出GPS的滞后时间,提高车辆的定位精度。     

磁场信号检测误差分析及补偿算法

针对载体自身磁场特性及三轴磁传感器误差特性建立了地磁导航干扰误差补偿模型,通过对模型进行简化变形,利用系统辨识的最小二乘估计算法(LS)求取误差特性参数.数据分析表明:该方法简单易实现,简化了复杂的求解过程,基本达到了误差补偿的要求.     

火星探测器转移轨道的自主导航方法

本文针对转移轨道火星探测器对自主导航的迫切需求,提出了一种基于小行星和X射线脉冲星交互观测的自主导航方法,并结合工程任务对上述量测信息的获取方式和获取条件进行了研究,仿真结果表明,与单独基于小行星或单独基于X射线脉冲星观测的自主导航系统相比,该方法不仅可获得更高的导航精度,为转移轨道中途修正提供准确的轨道信息,且工程实现简单,是一种可行的转移轨道火星探测器自主导航方案,可为我国火星探测器自主导航系统的设计提供参考.