基于L1输出反馈自适应方法的火箭姿态控制

针对运载火箭刚—弹耦合动力学模型,开展了基于L1输出反馈自适应方法的火箭姿态控制器设计.考虑到L1控制器低通滤波器环节可能在一定程度上减少弹性影响,分析了火箭不同低频模态对控制系统的影响情况.由于低通滤波器带宽与系统带宽存在相互制约关系,当无法通过低通滤波器设计消除低阶弹性影响时,结合校正网络设计L1输出反馈控制器.仿真结果表明,上述设计思路能够应对火箭低阶弹性问题,所设计的控制器控制效果良好,且在弹性频率变化时系统依然具有良好的暂态和稳态性能.     

LogGAN: a Log-level Generative Adversarial Network for Anomaly Detection using Permutation Event Modeling

Information Systems Frontiers - System logs that trace system states and record valuable events comprise a significant component of any computer system in our daily life. Each log contains...     

Modeling and Control of Hybrid-driven Gliding Motion for an Underwater Gliding Snake-like Robot

International Journal of Control, Automation and Systems - An underwater gliding snake-like robot (UGSR) combines the advantages of an underwater glider (UG) and an underwater snake-like robot...     

高速公路施工区车辆强制换道耗时生存模型

为研究高速公路施工区车辆强制换道行为及其影响因素,采用生存分析中的半参数分析方法建立强制换道耗时的乘法风险率模型.通过无人机拍摄采集高速公路施工区的车辆换道耗时及其影响因素数据,最终确立换道耗时Cox比例风险模型,对换道耗时数据进行Cox回归建模分析.结果表明:近77%的换道车辆在10 s内完成换道;小型车和中型车经养护施工区的换道耗时未发现显著性差别;对于相同的换道耗时,平峰期的累积生存率明显低于高峰期和过渡时期,而高峰期的累积生存率最高.建立的强制换道耗时生存模型可有效的定量分析车型和交通时段对高速公路施工区车辆换道行为的影响,可为高速公路施工区交通管理控制及车辆换道行为建模及仿真奠定一定的理论基础.     

Reaction mechanism and microstructure evolution of reaction sintered <Emphasis Type="Italic">h</Emphasis>-BN

Hexagonal boron nitride ceramic (h-BN) based on the nitridation of B powders was obtained by reaction sintering method. The effects of sintering temperature on the mechanical properties and microstructure of the resultant products were investigated and the reaction mechanism was discussed. Results showed that the reaction between B and N₂ occurred vigorously at temperatures ranging from 1 000 °C to 1 300 °C, which resulted in the generation of t-BN. When the temperature exceeded 1 450 °C, transformation from t-BN to h-BN began to occur. As the sintering temperature increased, the spherical particles of t-BN gradually transformed into fine sheet particles of h-BN. These particles subsequently displayed a compact arrangement to achieve a more uniform microstructure, thereby increasing the strength.     

中国犯罪防治的主流之路

我国目前犯罪预防体制存在较大漏洞,应从劳改释放人员和非劳改释放人员中的特定主体进行着重预防工作.问题解决应从国家机关、社会以及家庭等方面着手.心理预防是我国目前以至未来犯罪防治的主流之路.     

Simple Preparation of Crystal Co3（BTC）2·12H2O and Its Catalytic Activity in CO Oxidation Reaction

Crystalline metal-organic framework cobalt(Ⅱ) benzenetricarboxylate Co3(BTC)2?12H2O(MOF-Co) has been prepared using solvothermal method. The reaction of cobalt(Ⅱ) nitrate and 1,3,5-benzenetricarboxylic(BTC) acid in a mixed solution of N,N-dimethylformamide(DMF)/C2H5OH/H2O(1:1:1, ν/ν) at low temperature for short reaction times produced this crystalline compound. Compared with traditional hydrothermal method, a mixed solution method for the synthesis of crystalline metal complex was found to be highly efficient. After water molecules were removed from this metal complex, its exposed nodes served as active sites. When this MOF-Co was employed in the oxidation of CO, it showed good catalytic properties causing 100% conversion of CO to CO2 at low temperature of 160 ℃.     

Fe_(40)Co_(40)Zr_(10)B_9M_1(M=Cu,Ge,Ag)合金的热稳定性及微观结构研究

采用单辊快淬法制备Fe40Co40Zr10B9Cu1、Fe40Co40Zr10B9Ge1和Fe40Co40Zr10B9Ag1非晶合金薄带,并对3种合金在不同温度下进行热处理.利用差热分析仪(DTA)和X射线衍射仪(XRD)等测试手段对样品的热稳定性及微观结构进行研究.结果表明:Fe40Co40Zr10B9Cu1、Fe40Co40Zr10B9Ge1和Fe40Co40Zr10B9Ag13种合金的激活能分别为262.4、267.6和252.3 k J/mol,说明Cu元素、Ge元素和Ag元素的添加对合金的热稳定性影响不大,Ge元素的添加最有利于提高合金的热稳定性.3种合金的晶化过程相似:非晶→非晶+α-Fe(Co)→α-Fe(Co)+Zr Co3B2+Fe(Co)3Zr.     

论我国高职院校如何破解毕业生就业结构性矛盾

高等职业教育作为我国高等教育的重要组成部分,在现阶段经济社会发展中发挥越来越重要的作用。通过分析高职院校自身教学特点,提出教学体系构建和教改内容应加强与劳动力市场需求相对接,探讨破解毕业生就业结构性矛盾的措施,力求为社会培养高素质的技术技能型毕业生。     

基于改进Kendall-f算法的发电机定子温度分析

在线监测发电机定子温度可有效发现定子部分过热性故障,如何从检测的温度数据中提取反映定子故障预警的信息是目前国内外研究的热点。该文采用可变窗改进Kendall-f算法处理监测温度数据,提取其变化趋势特征信息;采用偏度分析提取监测温度异常值,从而正确诊断定子过热性故障,仿真分析及实验结果表明该方法有效提高了定子温度监测与预警的准确率。