基于滑模控制器的电弧传感焊接机器人轨迹跟踪控制研究

针对电弧传感焊接机器人系统的非完整约束性,建立了机器人运动学模型,通过讨论两后轮为控制输入的电弧传感焊接机器人轨迹跟踪问题,设计了一种滑模控制器,且应用Lyapunov稳定性理论保证了跟踪误差渐近收敛到零.经直线和圆弧2种轨迹跟踪的实验仿真结果,验证了所设计控制器的有效性和正确性.     

VHDL硬件描述语言在数字电路设计中的应用

随着数字电子技术的发展,传统的数字电路设计方法已不能满足现代数字集成电路系统设计要求,借助硬件描述语言完成硬件设计成为电子设计的趋势。通过介绍VHDL硬件描述语言的基本结构、基本特点和设计流程,以全加器为例说明用VHDL语言设计数字逻辑电路的方法,并给出了仿真结果。结果表明,VHDL对数字电路的硬件描述能力强,在设计上非常有效,是数字电路教学中全新的理论联系实际的方法和培养学生实际动手能力的有效工具。     

Estimation of components of energy balance on drifting ice over Arctic Ocean

Estimation and simulation were carried out for the components of ice-surface energy balance and tur bulent exchange parameters using the flux-profile method and the sinple biosphere model version 2 (SiB2, hereinafter) respectively based on the measured results for the atmosphere in the near-ice-surface layer, which were observed by the First Arctic Scientific Expedition of China in August, 1999 at a joint ice-research station (75°02′N, 160°51′W) on the drifting ice of Arctic Ocean. Evidence suggests that during the melting period of drifting ice the sum of the ice-released sensible heat and effective melting-consumed heat is greater than the net ice-absorbed radiation on the surface, with the excess heat coming via heat conduction from the deep layers of the ice mass. The simulated net radiation is systematical lv 18% greater than the measured results, while the simulated sensible heat flux is systematically 3% lower than the measured ones; and the simulated ice-surface heat flux differs noticeably from its calculation. Hence, we see that al though the measured sequences are short, the simulations of net radiation and sensible heat fluxes by the SiB2 model are comparatively good, the simulation of other forms of fluxes still needs to be improved.     

北冰洋浮冰上的能量分量的估算

根据1999年8月中国首次北极科学考察队在北冰洋高纬度浮冰区联合冰站(75°02′N,160°51′W)获得的近冰层大气边界层观测资料,通过通量-廓线方法和SiB2(SimpleBiospheremodelversion2)模式对冰面的能量平衡分量和湍流交换参数进行了估算和模拟.结果表明,北冰洋浮冰区在消融期间冰面释放的感热和融化有效耗热之和超过了冰面所吸收的净辐射,超出的部分热量主要来源于冰深层的热量向冰面传导.模拟的净辐射比实测值系统性高估18%,模拟的感热通量比计算结果系统性低估3%,模拟的冰面热通量误差较大.尽管观测资料序列不长,表明SiB2对北冰洋地区冰面的净辐射和感热通量模拟能力较好,对其他通量的模拟需作改进.     

基于Internet的交互式远程教育研究

详细论述了远程教育的技术、远程教育的几种模式、远程教育的研究内容和远程教育的发展趋势,以及目前远程教育存在的问题。     

Bohm模式下氘氚燃烧等离子体的动态稳定性数值计算

采用Grank-Nicholson差分方法,应用循环迭代,对氘氚燃烧的等离子体的动 态稳定性进行了数值分析。研究中采用了Bohm模式的热传导率,考虑了α粒子的反常扩散效应,电子和离子有不同的温度。考虑了动态反馈加热,使等离子体实现了稳态燃烧。数值分析结果与理论模型预言相一致。     

激光气功信息治疗仪的研制

为了探索激光和气功信息的结合应用,两年来我们进行了“激光气功信息治疗仪”的研制;用气功信息来调制激光针的输出光强,使其形成载有气功信息的激光束,用于穴位照射,对于这类新型的信疗仪,我们简称为JQS治疗仪,现在介绍的是He-Ne激光气功信息治疗仪,故简称:JQS-(He-Ne)治疗仪。     

Contrastive Analysis of the Middle Construction

The English Middle Construction (EMC), as a piculiar syntactic structure, shares its semantic features, but diversifies in its syntactic configuration compared with other langtages. This paper tries to have a contrast study of the Middle Construcitons between English and Chinese and find the two languages share the same semantic features that the incompatibility between the semantic quantitatives (SQs) of the Adverb (Adjunct in the syntactic term) and the SQs of the Verb denoted by the predicate of MC leads to the deactivization of the predicate by means of the Adjunct, functioning as a quantitative device, assign delimitation to the predicate, hence ensures the grammaticality of the construction. But syntatically, we agree that the NP Movement Approach accounts for the formation of EMC, while we argue in Chinese it is the verb raising that results in the MC. This paper f‘n-st represents the structural representation of the English Middle Construction; then the structural analysis is elaborated in comparison with that in Chinese, based on the previous studies; and finally the motivations of the Ecs in the perspective of syntactic and semantic functions are explored and hence a new hypothesis is raised to probe the similar construction in Chinese.