航天嵌入式软件数组越界缺陷特征研究

根据统计,数组越界是航天嵌入式软件开发过程中出现最多且最容易被遗漏的缺陷类型之一.目前自动化检测数组越界多基于抽象解释、符号执行、程序模型检验等方法,这些方法在误报、漏报、可扩展性等方面的表现依赖于软件及缺陷特征.分析了近三年航天嵌入式软件第三方测试中发现的94个数组越界问题,从缺陷模式和缺陷表现形式两方面分析得出10项航天嵌入式软件数组越界缺陷特征,并提出对设计具体检测方法关键的若干启示.进一步基于这些特征和启示探讨了数组越界检测算法针对中断驱动型程序的改进方向.     

速率模式飞轮姿态控制系统飞轮组合平稳切换方法

对速率模式飞轮姿态控制系统的能控性、稳定性和飞轮组合切换过程进行了研究，揭示了在飞轮组合切换过程中引起卫星姿态抖动的原因，提出了通过对残余角动量进行卸载并将卸载函数同时前馈到系统输入的方法，以保持卫星姿态的稳定度。从理论上证明了可引入残余角动量进行卸载，将卸载函数同时前馈到系统输入，并且不改变原系统的能控性和稳定性。给出了某卫星飞轮切换应用实例，说明了飞轮组合平稳切换方法的有效性。     

Facile Fabrication of Hierarchical Porous N/O Functionalized Carbon Derived from Blighted Grains Towards Electrochemical Capacitors

The hierarchical porous N/O co-functionalized carbon(HPNOC)was scalably prepared by using the lowcost and renewable blighted grains as the raw material coupled with mild KHCO_3 activation for electrochemical capacitors(ECs).The elemental N was in situ doped in the obtained HPNOC without any N-containing additives.Remarkably,the obtained HPNOC was endowed with a large specific surface area(about 2 624m~2·g~(-1)),high pore volume(about 1.35cm~3·g~(-1)),as well as high-content N/O functionalization(about 1.9%(in atom)N and about 10.2%(in atom)O.Furthermore,the as-resulted HPNOC electrode with a high mass loading of 5mg·cm~(-2 )exhibited competitive gravimetric capacitances of about 373.6F·g~(-1 )at 0.5A·g~(-1),and even about 260.4F·g~(-1 )at a high rate of 10A·g~(-1);superior capacitance retention of about 98.8%at 1A·g~(-1 )over 10 000consecutive cycles;and high specific energy of about 9.6W·h·kg~(-1 )at a power of 500W·kg~(-1),when evaluated as a promising electrode in 6mol KOH for advanced electrochemical supercapacitors.More encouragingly,the green synthetic strategy we developed holds a huge promise in generalizing for other biomass-derived carbon materials for versatile energy-related applications.     

Local Path Planning and Tracking Control of Vehicle Collision Avoidance System

Automotive collision avoidance technology can effectively avoid the accidents caused by dangerous traffic conditions or driver's manipulation errors.Moreover,it can promote the development of autonomous driving for intelligent vehicle in intelligent transportation.We present a collision avoidance system,which is composed of an evasive trajectory planner and a path following controller.Considering the stability of the vehicle in the conflict-free process,the evasive trajectory planner is designed by polynomial parametric method and optimized by genetic algorithm.The path following controller is proposed to make the car drive along the designed path by controlling the vehicle's lateral movement.Simulation results show that the vehicle with the proposed controller has good stability in the collision process,and it can ensure the vehicle driving in accordance with the planned trajectory at different speeds.The research results can provide a certain basis for the research and development of automotive collision avoidance technology.     

一种基于模糊控制的平稳滑翔再入制导律

针对升力式高超声速飞行器(LHV)再入滑翔过程中的周期性振荡现象，提出了一种基于模糊推理与控制的反馈调节方法以抑制振荡实现平稳滑翔。纵向制导在落点误差预测及指令校正的基础上，在倾侧角外环控制回路增加以高度变化率及空速作为输入的模糊控制器对倾侧角指令进行调节，横侧向制导通过航向角误差走廊约束及倾侧角反转逻辑实现大横程条件下的侧向控制。所提方法不依赖于准平衡滑翔条件(QEGC)，同时避免了参数化反馈控制律中的反馈项参数设计问题，具有较强的自适应能力。LHV制导实例仿真表明，所提方法可有效抑制振荡现象，满足终端约束及再入走廊约束，方法的鲁棒性也通过Monte Carlo仿真得到了验证。      

基于ESO的高超声速飞行器解耦控制

针对高超声速飞行器三通道具有强耦合的问题，提出一种基于扩张状态观测器的全通道解耦控制方法。该方法不需要根据耦合项特点设计耦合补偿模型，而是通过设计扩张状态观测器，将高超声速飞行器耦合项视为扰动，利用扩张状态观测器具有实时跟踪估计扰动的能力，将耦合项扰动估计出来。通过补偿控制来消除耦合的影响，从而完成解耦控制。进一步，通过LQR控制方法完成姿态控制系统的闭环反馈控制律设计，最终实现一种工程上实用的高超声速飞行器解耦控制方法，并通过数学仿真验证了该控制方法的正确性和有效性。     

NiCrAl/Diatomite可磨耗封严涂层制备及性能

分别利用大气等离子喷涂技术制备了Ni/Al粘结底层、火焰喷涂技术制备了NiCrAl/Diatomite可磨耗封严涂层，研究了喷涂距离、送粉速率、火焰气体总流量、喷涂角度和氧燃比等喷涂参数对生长速率和涂层硬度的影响。结果表明，在较低的氧燃比条件下（O₂∶C₂H₂<1.6），随着喷涂距离的增大，涂层生长速率逐渐下降，硬度先保持不变后逐渐上升；当O₂∶C₂H₂>1.6时，涂层的生长速率会随着喷涂距离的增大先增大后减小，硬度随之逐渐下降。随着喷枪对基体相对移动速度的增大，涂层生长速率略微下降，硬度略有上升。气体总流量的增大使得涂层的生长速率明显上升，硬度明显下降。随着送粉量的增大，涂层生长速率明显提高，硬度随之先上升后下降。     

Evolution of UV-B regulation and protection in plants.

Plants have evolved under the influence of UV-B radiation and have acquired systems for monitoring it and investing appropriate resources for protection against it, i.e., filters, quenchers of radicals and reactive oxygen species, and repair systems. An hypothesis for how plants monitor radiation has been presented.     

晶体管h参数微变等效电路的研究

晶体管h参数微变等效电路是电子技术中求解低频、小信号放大电路常用的分析方法.本文通过具体分析,将模拟放大电路进行了新的分类,并且明确而系统地给出运用微变等效电路求解各类模拟放大电路动态指标Av、ri和γ0公式、解题难点及规律.