摘要：A critical safe distance(CSD)model in V2V(vehicle-to-vehicle)communication systems was proposed to primarily enhance driving safety by disseminating warning notifications to vehicles when they approach calculated *** elaborately analyzing the vehicular movement features especially when braking,our CSD definition was introduced and its configuration method was given through dividing radio range into different communication *** on our definition,the needed message propagation delay was also derived which could be used to control the beacon frequency or ***,the detailed CSD expressions were proposed in different mobility scenarios by fully considering the relative movement status between the front and rear *** results show that our proposed model could provide reasonable CSD under different movement scenarios which eliminates the unnecessary reserved inter-vehicle distance and guarantee the safety at the same *** compared time-headway model always shows a smaller CSD due to focusing on traffic efficiency whereas the traditional braking model generally outputs a larger CSD because it assumes that the following car drives with a constant speed and did not discuss the scenario when the leading car suddenly *** from these two models,our proposed model could well balances the requirements between driving safety and traffic throughput efficiency by generating a CSD in between the values of the two models in most cases.

摘要：The paper studies the problem of fault detection filter design for uncertain linear continuous-time systems. A design procedure dealing with parameter uncertainties is proposed for residual generation, the sensitivity to fault and the robustness against disturbances are both enhanced on residual outputs through satisfying some performance indexes. By the aid of the generalized Kalman-Yakubovich-Popov(GKYP)lemma, the fault sensitivity performance index can be dealt with in the given frequency range directly, which avoids approximations associated with frequency weights of the existing techniques. An iterative algorithm based on linear matrix inequality(LMI)is given to obtain the solutions. A numerical example is given to illustrate the effectiveness of the proposed methods

摘要：主要研究单晶冷却叶片强度和疲劳寿命的尺寸效应影响,实验试样是从商业冷却叶片上加工的小尺寸试样。实验研究了冷却叶片的强度尺寸效应;结合单晶材料的本构关系及其应力因子模拟了冷却叶片的强度和疲劳寿命;对于两类冷却叶片的强度和寿命进行数值模拟;拉伸试验发现,对于小试样其拉伸极限强度小于标准试样,因此,引入安全系数来评估冷却叶片的强度。对于小尺寸试样和标准尺寸试样的强度和疲劳寿命的实验比较表明,尺寸变化对冷却叶片的强度和疲劳寿命有显著影响。本研究可以为单晶冷却叶片的强度评估和结构设计提供参考。

摘要：浮式平台概念的选择及其结构设计是深水工程项目的关键环节之一.它决定了平台在波浪载荷作用下的动力学响应、立管在深水条件下的运动以及进行平台建造与安装的技术难度等.结构强度、结构的抗疲劳性能以及结构的整体和局部稳定性能是浮式平台设计必须重点考虑的三个主要方面.总结了当前浮式平台设计的主要方法和它的主要任务以及技术要求,着重分析了设计过程中的主要技术难点及重点;最后,讨论了浮式平台结构设计的潜在发展趋势.

摘要：According to previous studies,stiffened shells with convex hyperbolic generatrix shape are less sensitive to *** this study,the effects of generatrix shape on the performances of elastic and plastic buckling in stiffened shells are ***,a more general description of generatrix shape is proposed,which can simply be expressed as a convex B-spline curve(controlled by four key points).An optimization framework of stiffened shells with a convex B-spline generatrix is established,with optimization objective being measured in terms of nominal collapse load,which can be expressed as a weighted sum of geometrically imperfect *** effectiveness of the proposed framework is demonstrated by a detailed comparison of the optimum designs for the B-spline and hyperbolic generatrix *** decrease of imperfection sensitivity allows for a significant weight saving,which is particularly important in the development of future heavy-lift launch vehicles.

摘要：电离层频率调制导致地表面杂波的多谱勒展宽,极大地限制了高频天波雷达的目标探测性能。本文针对这种电离层频率调制,给出了一种级联的两步校正处理的方法。在第一步校正中,首先分析这种时变信号的时频分布,并设计了一种谱峰追踪方法从时频分布中获得粗糙的电离层频率调制估计。然后采用基于分段多项式相位模型的参数化方法作二次校正处理,消除残余调制污染。模拟结果表明,即使对Bragg峰发生混叠的重污染的情形,这种级联的校正方法都具有非常好的效果。

摘要：A scheme of flexible colorless remote note with reflective semiconductor optical amplifier （RSOA） assisted Michelson interferometer is proposed. This is capable of generating an optical carrier suppressed signal at a specific radio frequency to suppress the penalty brought about by Rayleigh backscattering and reflection in a full-duplex single fiber transmission network. Simulations are conducted, and the validation of the proposal is discussed by observing the penalty eye opening factor. The results are useful for designing cost-effective multi-wavelength passive optical network （PON） or radio-over-fiber （RoF） systems.

摘要：硅基负极具有理论容量高、工作电位低、环境友好、丰度高等优点,被认为是下一代锂离子电池中最有希望替代石墨负极的材料之一.然而,硅负极在脱嵌锂过程中体积膨胀大、界面反应剧烈是制约其进一步实际应用的关键问题.合理设计硅纳米结构有助于解决这些问题.本文首先介绍了高容量锂电池用纳米硅负极的基本科学问题,然后重点介绍了其设计、制备、原位表征和失效机理等方面的最新进展,总结到目前为止关键的经验以促进硅负极在实际锂电池中的应用.最后展望了硅负极未来的发展和挑战.

摘要：将基于单循环方法的可靠性分析(SLBRA)与多学科可行(MDF)设计优化相结合,提出了一种基于可靠性的多学科设计优化(RBMDO)方法。在优化过程中使用Kriging近似模型以不断提高模型精度,解决了MDF方法反复进行多学科分析、计算量较大的问题。该方法在可靠性分析过程中避免了优化迭代,从而提高了计算效率。以涡轮叶片的设计优化为例,对该方法进行了验证并与传统双循环方法进行了对比。结果表明,优化结果满足可靠性的要求。与双循环方法相比,优化效率明显提高,证明了该方法在工程应用中可行且有效。

摘要：为了结合等通道转角和分流挤压技术生产板材,研究了一种等通道转角分流（P-ECAP）挤压新技术.通过有限元方法研究了用于高速列车的6005A铝合金板材的挤压.在传统分流模具的分流通道内设计了等通道转角工艺.预测了不同通道转角对P-ECAP工艺挤出板材的废料长度变化的影响;研究了通道转角和挤压速度对最大工件温度和其他场变量的影响.结果表明：板材在通道转角为160＆#176;时具有最好的尺寸精度,而且废料的尺寸也最小;较为合理的挤压速度为3～5 mm/s.另外,当挤压速度从1mm/s增加到9mm/s时,挤压力的峰值上升了49％,工件的最高温度升高了70℃.在通道内的转角变形区,等效应变有上升趋势;挤出板材的焊合区和模具边缘最大主应力为张应力.