刹车片背板弯挤成形工艺研究

针对刹车片背板传统成形工艺的缺陷，采用FEM方法对刹车片背板成形过程进行了数值模拟，确定了弯曲一挤压复合成形的工艺路线。根据有限元分析的结果，分析了不同尺寸的毛坯对工件成形过程及成形质量的影响，提出了刹车片背板弯挤毛坯尺寸的选择原则。设计了刹车片背板的弯挤成形模具，在一副模具中实现弯曲、挤压两种不同的变化。     

ZL114A铸铝搅拌摩擦焊接头性能

研究了采用不同焊接参数时ZL114A铸铝搅拌摩擦焊接头的金相组织、硬度分布及力学性能。结果表明，ZL114A铸铝的搅拌摩擦焊焊接性良好。焊核区的微观组织是无方向性的、细小的等轴晶粒。细化的硅粒子均匀布满整个焊核区。与粗大的树枝状母材相比，焊核晶粒细小、均匀而致密，没有观察到气孔等缺陷。焊缝区硬度分布较母材稳定，变化范围小。随着焊速增加，硅粒子所占体积比逐渐下降。热一机械影响区晶粒被拉长。接头的力学性能与焊接参数的匹配有关系。采用高焊速及转速与焊速比在3左右，获得的接头抗拉强度可达到母材的91％。焊后经T6热处理，可与同炉热处理母材等强。     

GCr15钢的ELID磨削性能实验研究

为了探讨GCr15钢的ELID（Electrolytic In-process Dressing）磨削性能，在基于大量实验的基础上，对GCr15钢采用ELID磨削时磨削力的变化规律进行了详细分析，并将磨削力、磨削表面粗糙度与普通磨削进行了比较。结果表明，采用铸铁结合剂CBN砂轮进行ELID磨削时磨削力几乎不随时间的变化而变化，而采用白刚玉砂轮进行磨削时的磨削力随时间的变化不断增大，在线电解修整使CBN砂轮在磨削过程中始终保持良好的磨削性能，有利于节省砂轮修整时间，提高加工效率。在ELID磨削中，采用微细砂轮进行磨削可以获得很低的表面粗糙度，实现对GCr15钢的超精密镜面磨削。     

球铁塑性变形中石墨球变形行为的观察与分析

用光镜和电镜对球铁不同变形条件下石墨球的变形形貌进行观察和分析,揭示了石墨球的变形行为和影响因素。     

Process of friction-stir welding high-strength aluminum alloy and mechanical properties of joint

The process of friction-stir welding 2A12CZ alloy has been studied. And strength and elongation tests have been performed, which demonstrated that the opportunity existed to manipulate friction-stir welding parameters in order to improve a range of material properties. The results showed that the joint strength and elongation arrived at their maximums ( 331 MPa and 4% ) at 37. 5 mm/min and 300 rpm. As welding parameters changing, joint tensile strength and elongation had similar development. Hardness measurement indicated that the weld was softened. However, there was considerable difference in softening degree for different joint zone. The weld top had lower hardness and wider softening zone than other zone of the weld. And softening zone at advancing side was wider than that at retreating side.     

钛合金表面电火花沉积强化研究现状

介绍了电火花表面沉积工艺的基本原理和技术特点，以及国内外电火花沉积技术在钛合金表面强化领域的研究现状。在钛合金表面进行电火花沉积，可得到具有高硬、耐磨、耐高温氧化、低摩擦系数的特殊表面涂层。虽然电火花表面强化技术具有特殊的强化效果，但存在着电火花强化层的表面粗糙度不容易控制、生产效率低、强化工艺不稳定的缺点。因此，今后要深入研究电火花放电机理，进一步提高强化效率，研究不同电极、基体材料的强化工艺。     

Stochastic consensus control with finite frequency specification for Markov jump networks

A stochastic finite frequency consensus protocol for directed networks with Markov jump topologies and external disturbances is proposed in this paper. By introducing the frequency band information into consensus control design, the disagreement dynamics of interconnected networks asymptotically converge to zero with an improved level of disturbance attenuation in the specific frequency band. In addition, the new model transformation approach is presented by exploring certain features of Laplacian matrix in real Jordan form, which leads to more generality of the designed protocol. A numerical example validates the potential of the developed results. Copyright © 2015 John Wiley & Sons, Ltd.     

A Train Dispatching Model Under a Stochastic Environment: Stable Train Routing Constraints and Reformulation

After major capacity breakdown(s) on a railway network, train dispatchers need to generate appropriate dispatching plans to recover the impacted train schedule from perturbations and minimize the expected total train delay time under stochastic scenarios. In this paper, we propose a cumulative flow variables-based integer programming model for dispatching trains under a stochastic environment on a general railway network. Stable Train Routing (STR) constraints are introduced to ensure that trains traverse on the same route across different capacity breakdown scenarios, which are further reformulated to equivalent linear inequality constraints. Track occupancy and safety headways are modelled as side constraints which are dualized through a proposed Lagrangian relaxation solution framework. The original complex train dispatching problem is then decomposed to a set of single-train and single-scenario optimization subproblems. For each subproblem, a standard label correcting algorithm is embedded for finding the time dependent least cost path on a space-time network. The resulting dual solutions can be transformed to feasible solutions through priority rules. Numerical experiments are conducted to demonstrate the efficiency and effectiveness of the proposed solution approach.     

Optimal control on special Euclidean group via natural gradient algorithm欧几里德群的最优控制问题

Considering the optimal control problem about the control system of the special Euclidean group whose output only depends on its input is meaningful in practical applications. The optimal control considered here is described as the output matrix is as close as possible to the target matrix by adjusting the system input. The geodesic distance is adopted as the measure of the difference between the output matrix and the target matrix, and the trajectory of the control input obtained in the process is achieved. Furthermore, some numerical simulations are shown to illustrate our outcomes based on the natural gradient descent algorithm for optimizing the control system of the special Euclidean group.     

智能手机的无线身份认证系统应用研究

在现有身份认证技术的基础上,研究了一种利用智能手机作为身份认证载体、结合了二维条码和蓝牙技术、具有较高安全性和易用性的身份认证系统,并对系统实现的关键技术进行了研究。