《数字逻辑》课程教学改革的探索

为了适应科技的迅速发展和新世纪社会对人才新的需求．从我校的具体情况出发,从理论教学、实践教学等方面,对传统的《数字逻辑》课程在教学手段、内容、和考核方式上进行探索,通过采取这一系列改革措施,提升教学质量,从而有助于学生更积极主动地进行学习,发挥其想象力和创造力。     

Passivity-based sliding mode control for a polytopic stochastic differential inclusion system

Passivity-based sliding mode control for a polytopic stochastic differential inclusion (PSDI) system is considered. A control law is designed such that the reachability of sliding motion is guaranteed. Moreover, sufficient conditions for mean square asymptotic stability and passivity of sliding mode dynamics are obtained by linear matrix inequalities (LMIs). Finally, two examples are given to illustrate the effectiveness of the proposed method.     

A dynamic model for the efficiency optimization of an oscillatory low grade heat engine

A simple approach is presented for the modeling of complex oscillatory thermal-fluid systems capable of converting low grade heat into useful work. This approach is applied to the NIFTE, a novel low temperature difference heat utilization technology currently under development. Starting from a first-order linear dynamic model of the NIFTE that consists of a network of interconnected spatially lumped components, the effects of various device parameters (geometric and other) on the thermodynamic efficiencies of the device are investigated parametrically. Critical components are highlighted that require careful design for the optimization of the device, namely the feedback valve, the power cylinder, the adiabatic volume and the thermal resistance in the heat exchangers. An efficient NIFTE design would feature a lower feedback valve resistance, with a shorter connection length and larger connection diameter; a smaller diameter but taller power cylinder; a larger (time-mean) combined vapor volume at the top part of the device; as well as improved heat transfer behavior (i.e. reduced thermal resistance) in the hot and cold heat exchanger blocks. These modifications have the potential of increasing the relevant form of the second law efficiency of the device by 50% points, corresponding to a 3.8% point increase in thermal efficiency.     

Invertible matrices and semilinear spaces over commutative semirings

This paper deals with invertible matrices and semilinear spaces over commutative semirings. Some necessary and sufficient conditions for matrices to be invertible over commutative semirings are obtained. The condition under which the cardinality of each basis of semilinear space of n-dimensional vectors is n is given. In the end, the factor rank of matrices over semirings is investigated.     

台达运动控制型PLC应用技术

本文介绍台达运动控制型PLC的应用技术。重点描述了台达DVP20PM运动控制型PLC的硬件和软件结构以及运动控制编程，并介绍在其应用中的方法及特点。     

汽车纵梁数控冲孔新技术

本文阐述了汽车纵梁数控冲孔新技术的发展和新工艺的应用,简要地分析了典型数控冲孔设备--腹兼平数控冲孔生产线的工作原理和技术特点.     

Isomorphic Implication

We study the isomorphic implication problem for Boolean constraints. We show that this is a natural analog of the subgraph isomorphism problem. We prove that, depending on the set of constraints, this problem is in P, or is NP-complete, or is NP-hard, coNP-hard, and in P_‖^NP. We show how to extend the NP-hardness and coNP-hardness to P_‖^NP-hardness for some cases, and conjecture that this can be done in all cases. Supported in part by grants NSF-CCR-0311021 and DFG VO 630/5-1 and VO 630/5-2. An extended abstract of this paper appears in Proceedings of the 30th International Symposium on Mathematical Foundations of Computer Science (MFCS 2005), pp. 119–130, Springer-Verlag Lecture Notes in Computer Science #3618, August 2005. Work of M. Bauland done in part while visiting CASCI’s Laboratory for Complexity at Rochester Institute of Technology. Work of E. Hemaspaandra done in part while on sabbatical at the University of Rochester.     

An investigation on general corrosion and pitting of iron with the in-line digital holography

In the anodic processes of the iron electrode in both neutral and acidic solutions, general corrosion and pitting dynamical processes in the presence of chloride ions were observed in situ with the in-line digital holography. The dynamic processes such as formation and dissolution of the passive film, initiation and propagation of pitting have been studied. During the general corrosion, not only is the temporal structure in order, evidenced by the regular change of current with time, but also the spatial structure, indicated by the uniform fringes in the holograms at the electrode/electrolyte interface. However, during the pitting processes, the order of the spatial structure is destroyed, which is indicated by the wrinkled fringes in the holograms; the temporal order is broken as well evidenced by the irregular change of current with time. The experimental result shows that there is synergistic effect between H⁺ and Cl⁻ on both the initiation stage and the propagation stage. With the presence of chloride ions, pitting occurs much more easily in acidic solution than in neutral solution.     

一种直线导轨用车床尾座的设计

传统平床身数控车床的加工精度和快移速度已经难以满足机械加工行业高速发展的需求,直线导轨在平床身数控车床上的应用可以有效解决这一不足。针对传统平床身数控车床的尾座操作不是很便利的现象,设计一款采用新型卡紧方式、符合人机工程学的直线导轨用车床尾座。     

Mixed-ion linear actuation behaviour of polypyrrole

The linear actuation of polypyrrole (PPy) films polymerized at 0.85 V (versus Ag-wire) and −27 °C in propylene carbonate solutions of tetrabutylammonium trifluoromethanesulfonate (TBACF₃SO₃) was investigated in the same monomer-free electrolyte. The actuation properties were evaluated by electrochemomechanical deformation measurements (ECMD) during cyclic voltammetry and potential step experiments. The ECMD response revealed mixed-ion actuation behaviour for the film, namely the polymer film actuation was dominated by cation movement at potentials less than 0 V and anion movement at potentials greater than 0 V, with film lengthening seen at both potential extremes. It was found that the ratio of cathodic to anodic actuation can be modulated by the scan rate. Longer-term actuation (50 potential steps from −1 V to 0 V, or from 0 V to +1 V), indicated better film stability when cycled in the anodic region. Changing the electropolymerisation potential to a higher value of 1.2 V led to a modification in ECMD characteristics for the PPy/CF₃SO₃ films.