Bifurcation analysis of visual angle model with anticipated time and stabilizing driving behavior

In the light of the visual angle model (VAM), an improved car-following model considering driver's visual angle, anticipated time and stabilizing driving behavior is proposed so as to investigate how the driver's behavior factors affect the stability of the traffic flow. Based on the model, linear stability analysis is performed together with bifurcation analysis, whose corresponding stability condition is highly fit to the results of the linear analysis. Furthermore, the time-dependent Ginzburg-Landau (TDGL) equation and the modified Korteweg-de Vries (mKdV) equation are derived by nonlinear analysis, and we obtain the relationship of the two equations through the comparison. Finally, parameter calibration and numerical simulation are conducted to verify the validity of the theoretical analysis, whose results are highly consistent with the theoretical analysis.     

矿井索车的优化设计

对矿井索车优化设计中的几个关键性问题进行了探讨，包括驱动轮和尾轮的设计、钢丝绳直径的选择计算、托绳轮间距的确定、绳卡的设计、张紧力和张紧行程的确定、互锁问题的解决等。     

In-Situ Intrinsic Interface Strength Measurement at Elevated Temperatures and its Relationship to Interfacial Structure

A previously developed laser spallation technique has been modified to measure the tensile strength of thin film interfaces in-situ at temperatures up to 1100°C. Tensile strengths of Nb/A-plane sapphire, FeCrAl/A-plane sapphire and FeCrAlY/A-plane sapphire were measured up to 950°C. The measured strengths at high temperatures were substantially lower compared with their corresponding strengths at ambient temperature. For example, at 850°C, the interface tensile strength for the Nb/sapphire (151 ± 17 MPa), FeCrAl/sapphire (62 ± 8 MPa) and FeCrAlY/sapphire (82 ± 11 MPa) interface systems were lower by factors of approximately, 3, 5, and 8, respectively, over their corresponding ambient values. These results underscore the importance of using such in-situ measured values under operating conditions as the failure criterion in any life prediction or reliability models of such coated systems where local interface temperature excursions are expected. The results on alloy film interfaces also demonstrate that the presence of Y increases the strength of FeCrAl/Al₂O₃ interfaces.     

双预脉冲驱动X射线激光实验研究

 在“星光-Ⅱ”激光装置上进行了双预脉冲驱动类氖铬X射线激光实验，介绍了实验方法和实验结果，并对结果进行了简短讨论。由于目前“星光”装置输出能量较低，所进行的双预脉冲驱动未能显著提高X射线激光强度，改变预脉冲幅度时X射线激光强度也未有显著变化。利用MED103程序进行了模拟计算，其结果与实验结果一致。     

拖拉机主减速主动锥齿轮轴的辅助设计

本文对拖拉机主减速主动锥齿轮轴提出了一种新的设计方法，为提高该件的设计水平提供了可靠数据．     

具有优先级的深度确定性策略梯度算法在自动驾驶中的应用

深度确定性策略梯度(deep deterministic policy gradient,DDPG)算法在自动驾驶领域中应用广泛,但DDPG算法因采用均匀采样而导致低效率策略比例较高、训练效率低、收敛速度慢等.提出了基于优先级的深度确定性策略梯度(priority-based DDPD,P-DDPG)算法,通过优先级采样代替均匀采样来提升采样利用率、改善探索策略和提高神经网络训练效率,并且提出新的奖励函数作为评价标准.最后,在开源赛车模拟(The Open Racing Car Simulator,TORCS)平台上对P-DDPG算法的性能进行了测试,结果表明相对于DDPG算法,P-DDPG算法的累积奖励在25回合之后就有明显提升而DDPG在100回合之后训练效果才逐渐显现,提升约4倍.P-DDPG算法不仅训练效率提升且收敛速度加快.     

数据驱动下交通异常行为的双层识别模型

为实现对车辆异常行为的准确识别,提高车辆行驶的安全性,提出了一种基于支持向量机(support vector machine, SVM)、监督学习与长短期记忆(long short term memory, LSTM)深度学习的交通异常驾驶行为双层识别模型。首先,对车辆轨迹数据筛除和滤波,构建异常行为数据集;其次,从异常行为轨迹特征中提取出特定异常行为的特征标签,并人为标定在训练集中;再次,构建SVM模型对训练集进行粗识别,基于SVM的二分法原理,从测试集中筛选出异常行为;最后,通过LSTM时间序列模型构建具体种类的异常行为模型,并通过深度学习的方法,从异常行为数据中细分为蛇形驾驶、急速变向、侧滑、大半径转弯、快速U型转弯、急刹车等具体的异常驾驶行为。本次实验选用下一代仿真(next generation simulation, NGSIM)数据中US-101高速公路和peachtree城市道路的数据集的轨迹数据验证SVM和LSTM双层识别模型的性能,包括均方根误差、识别准确率等。结果表明,构建的双层识别模型在第一层有98%的识别准确率,第二层有超过80%的识别准确率,可以较为准确地识...     

N-苄叉基-1-氨基-萘及其类似物的构象与分子扭曲的共轭 驱动力

确定了N-[(4-二甲基氨基)-苄叉基]-2-氨基苯并咪唑(1)，N-[(4-二甲基氨基)-苄叉基]-2-氨基苯并噻唑(2)和N-苄叉基-1-氨基-萘(3)的晶体结构。利用AM1，RHF，DFT方法和STO-3G,4-31G,6-311G及6-311G基组，优化每个分子的23个扭曲构象(θ=0°～-89°)。尽管不同方法得到的最优构象的扭角不同，分子扭曲的驱动力总是起因于电子作用，在任一分子、任何电子态中，离域的π体系总是失稳定的，全平面构象不是π体系最稳定的构象。π电子的离域是分子扭曲的驱动力之一，与经典观点相反，非键原子间的核排斥作用是分子扭曲的阻力，而不是动力。     

基于广义逆的受控机构优化

基于受控原动件的机械特性和受控机构二自由度的特点，建立精确实现多点轨迹受控机构的圆拟合优化模型．提出运用广义逆求解补偿运动位移的方法。     

喷涂掘进煤巷抑制瓦斯涌出的研究

通过喷涂煤壁可抑制瓦斯涌出原理，建立了瓦斯在煤体与喷涂层中渗流传质的物理数学模型，得出煤壁喷涂前后瓦斯渗流压力的分布及瓦斯涌出量随煤层透气系数的变化规律，提出了煤层透气系数的测定方法及喷层厚度的计算方法，揭示出喷层厚度与喷层的透气性及喷层与煤壁的粘结应力的相互关系。