非均匀和均匀布风流化床中颗粒的运动分析

通过实验得到了非均匀布风和均匀布风流化床内示踪颗粒在床层内的运动轨迹，在此基础上，分析了流化床中示踪颗粒的混合和扩散特性。结果表明配风方式对于示踪颗粒的扩散有很大影响，内旋流流化床具有较好的横向和纵向扩散特性，有利于使流化床内横向不均匀的状况得到改善。     

固体粒子在直流式除尘器中湍流脉动的数值模拟

本文对直流除尘器涡室内固体粒子的湍流脉动现象进行了数值分析,通过气体速度随机脉动谱,把气相湍流运动对固体粒子运动的影响引入粒子的运动平衡方程中,用拉格朗日法模拟了粒子的轨迹及其扩散运动,应用四阶龙科库塔方法求解粒子的运动方程。计算结果表明对粒子的数值模拟可以较好地预测除尘器的性能,如除尘器的切割粒径。     

扫描隧道显微镜针尖调制的薄膜表面的原子扩散

采用原子尺度的模拟方法,探讨了在零偏压下扫描隧道显微镜(STM)针尖调制的金属表面岛上原子运动及岛边的层间质量输运. 研究结果显示STM的移动对岛上及岛边的原子扩散有重要的影响. 针尖与吸附原子的交互作用及岛和基体中强的形状变化影响了岛上吸附原子的跳跃扩散及岛边的跳下扩散和交换扩散过程. 研究发现,通过调节针尖与基体的垂直距离及针尖与吸附原子的水平距离,可以降低岛上吸附原子的跳跃扩散能垒及岛边的跳下扩散和交换扩散能垒,从而实现薄膜由三维生长模式向二维生长模式的转变. 关键词： 扫描隧道显微镜 原子运动 质量输运     

基于SERS技术的靶向修饰金纳米探针 用于Hela细胞的检测

表皮生长因子受体(EGFR)是一种肿瘤表面标记性蛋白。本文报道了基于anti-EGFR功能化金纳米棒探针AuNRs probes的表面增强拉曼散射(SERS),用于EGFR阳性肿瘤细胞的检测。通过AuNRs probes上anti-EGFR特异性结合到EGFR阳性癌细胞上,可使修饰于金纳米棒表面的拉曼活性染料4-巯基苯甲酸(4-MBA)位于1 100 cm~(-1)和1 600 cm~(-1)的特征峰强度得到信号增强。该SERS探针由于具有生物兼容性好、细胞拉曼信号稳定、特异性高等优点而具有巨大的临床应用前景。     

双电荷在匀强磁场中的运动轨迹

给出了质量和电荷值相等的双电荷在匀强磁场中的运动方程, 讨论了运动守恒量和轨迹特性; 数值求 解方程, 给出了轨迹封闭时轨迹曲线     

多弹簧振子耦合系统运动研究

通过理论分析,得到了多弹簧振子耦合系统的解析解,利用Matlab对其进行数值模拟,作出了系统的运动曲线及相轨迹,直观地显示了系统的运动情况,并通过对不同数量弹簧振子耦合系统运动曲线及相轨迹的比较、分析,给出了系统的运动特征.     

三平动绳牵引并联机器人轨迹预处理算法

研究了一种新型飞行摄像平台,能够实现摄像机在大范围的三维空间内可以沿任意轨迹快速运动的摄像平台;摄像平台的运动由四台伺服电机带动四根缆绳并联拖动;绳牵引并联机器人是一种将电机的运动和力以绳为介质并行地转换为末端执行器运动和力的装置,具有结构简单、工作空间大、惯性小等优点;运动过程中满足轨迹光滑、不能出现停顿、振动,为了获得连续、平稳、无噪声的轨迹,文章采用轨迹预处理的方法,当出现轨迹不光滑,且影响了拍摄质量的情况下,采用三次样条圆弧插补的方法对其进行光滑处理,仿真结果表明该圆弧插补预处理算法能够很好地解决吊舱在高速运行而引起加速度过大的问题,进而达到提高运行效率的目的。     

氢及其同位素在溴化丁基橡胶中渗透的分子模拟

使用分子动力学(MD)和巨正则蒙特卡罗(GCMC)的方法,对H_2,D_2,T_2在溴化丁基橡胶(BIIR)中的扩散和溶解行为进行了计算模拟,运用自由体积理论探讨了气体分子在聚合物内的扩散机理,并得出气体的运动轨迹。结果表明:对氢及其同位素而言,质量越小,运动速度越快,扩散系数越大,溶解度系数比较接近,渗透系数的模拟值与实验值基本吻合,为提高材料的阻隔性能提供了一定理论基础,同时预测出硫化溴化丁基橡胶对氚水也有较好的阻隔性能。     

基于背景运动补偿的红外目标运动分析

 介绍了基于运动补偿的红外目标运动分析方法。阐述了运动补偿的必要性、过程原理和实现方法，并用之于对红外运动目标的视频跟踪，通过用背景运动量补偿目标的相对运动量，得到明确而直观的目标运动轨迹，有效地揭示了目标运动的内在规律，为红外目标的轨迹预测与跟踪提供了更有效的分析依据。     

抗EGFR单克隆抗体表面电荷不均一性的分析条件优化

优化离子交换色谱法分析抗表皮生长因子受体(Epidermal growth factor receptor,EGFR)单克隆抗体表面电荷不均一性的条件。考察了离子交换色谱法分析抗EGFR单克隆抗体表面电荷不均一的条件,包括色谱柱、流动相pH、梯度及柱温。离子交换色谱法分析表面电荷不均一性的最佳条件:TSK-gelCM-STAT离子交换色谱柱、流动相pH6.0、合适的起始梯度及梯度陡度有利于电荷不均一性各组分的分离,柱温为40℃。合适的分析条件能够使单克隆抗体表面电荷不均一性各组分在离子交换色谱柱上得到最佳分离及获得较高灵敏度。     

Directional emission from whispering-gallery modes in deformed fused-silica microspheres

Highly directional emissions from whispering-gallery modes are demonstrated in deformed nonaxisymmetric fused-silica microspheres. Ray trajectory analysis indicates that ray dynamics in a three-dimensional reso-nator differs qualitatively from that of a two-dimensional system, with Arnol'd diffusion playing an essential role in the three-dimensional system.     

基于个体张量分解与模态的头相关传输函数重构

远场头相关传输函数(HRTF)随声源方向、频率以及个体变化。完整HRTF的数据量很大,且测量或计算每个人的高方向分辨率HRTF是很困难的。本文提出一种从少量方向的测量或计算重构高方向分辨率HRTF的方法。基于HRTF张量分解,远场HRTF可分解为方向模态、频率模态和少量个体模态的张量组合。通过对已有的基线HRTF数据库进行统计分析,可得到与个体无关的方向模态矩阵和频率模态矩阵。而对于任何新的个体,只要少量方向的测量或计算HRTF即可估计出个体模态的变化,并重构出高方向分辨率的HRTF数据。对两个HRTF数据库的计算表明,采用11个个体模态即可表示超过98%的个体相关的HRTF能量变化,并从大约30个方向的测量或计算HRTF重构出高方向分辨率的HRTF幅度。心理声学实验验证了提出的方法。该方法可用于简化个性化HRTF的测量或计算。     

Design of optical coupling systems between two-dimensional quasi-stadium laser diodes and single-mode optical fibers

Optical coupling systems between a two-dimensional quasi-stadium laser diode and single-mode optical fibers using gradient-index rod lenses are designed for both stable and unstable laser resonators for the first time. A novel numerical approach using a combination of the extended Fox-Li calculation method and Gaussian beam transformations is proposed. In the case of a stable laser resonator, two kinds of beam propagation modes appear, namely the axis mode, in which an optical beam propagates along the cavity axis, and the ring mode, in which optical beams propagate along the diamond-shaped trajectory. The coupling efficiencies are found to be 54% for the axis mode and 52% for the ring mode. In contrast, an unstable laser resonator exhibits complicated modes, in which several highly directional beams are emitted from the end mirrors. The total coupling efficiency for these output beams is calculated to be 9.6%. The 3-dB tolerances for the lens pitch and alignment angles of the gradient-index rod lenses are also discussed.     

Interference, Reduced Action, and Trajectories

Instead of investigating the interference between two stationary, rectilinear wave functions in a trajectory representation by examining the trajectories of the two rectilinear wave functions individually, we examine a dichromatic wave function that is synthesized from the two interfering wave functions. The physics of interference is contained in the reduced action for the dichromatic wave function. As this reduced action is a generator of the motion for the dichromatic wave function, it determines the dichromatic wave function’s trajectory. The quantum effective mass renders insight into the behavior of the trajectory. The trajectory in turn renders insight into quantum nonlocality.     

Regular and chaotic transport of impurities in steady flows

This paper considers the properties of the transport of impurity particles in steady fluid flows and describes the principal modes of particle motion. An impurity consisting of particles with a lower density than that of the medium is localized at stationary points of the flow, whereas a heavy impurity can perform a spatially unbounded motion. The conditions for the transition from the bounded motion of a heavy impurity to the long-range transport mode, which occurs as a result of a loss of the stability of the heteroclinic trajectory, are obtained for a model two-dimensional flow having an eddy-cell structure. A mode is found in which a particle, after being transported over a long distance, is trapped forever within the confines of one cell. The transition from regular to chaotic particle transport is analyzed. The question of the effect of a small noise (for example, molecular diffusion) on the character of the motion of a heavy impurity is investigated. It is shown that this effect is important at high viscosity and leads to a transition from bounded motion of the impurity particle to diffusion-type chaotic motion. (c) 1994 American Institute of Physics.     

自动化控制下机械手臂运动轨迹研究

对机械手臂运动轨迹进行优化控制,能改善机械手臂的自动控制性能。为了提高机械臂的控制稳健性,提出一种基于变结构模糊PID控制的机械手臂运动轨迹优化控制模型。首先采用末端效应逆运动学模型构建机械手臂的运动规划约束参量数学模型,采用七自由度运动空间重构方法建立机械手臂运动的动力学方程。然后通过纵向定常运动,分析建立机械手臂整定控制目标函数,求解机械臂在抓取作业过程中的最佳导引控制律,采用变结构模糊PID控制方法进行运动轨迹的误差修正,实现机械臂自动控制优化。最后通过仿真实验进行控制性能测试,结果表明,采用该方法进行机械手臂运动轨迹控制的精度较高,对机械臂位形变化轨迹的预测准确性较好。     

Description of nonrigid rotation in small atomic clusters

The dependence of the internal dynamics of triatomic van der Waals clusters on the rate of nonrigid rotation has been studied. The method of decomposition of the system's motion into orthogonal modes of the motion has been proposed. Additionally, a new method of separation of the kinetic energy, captured by the modes, into rotational and vibrational components has been developed. It has been found that the most significant factor for the chaotic behavior of the cluster is the partitioning of the vibrational and rotational energies among the modes.     

基于大数据分析的移动对象轨迹预测方法

对移动对象的轨迹预测将在移动目标跟踪识别中具有较好的应用价值。移动对象轨迹预测的基础是移动目标运动参量的采集和估计,移动目标的运动参量信息特征规模较大,传统的单分量时间序列分析方法难以实现准确的参量估计和轨迹预测。提出一种基于大数据多传感信息融合跟踪的移动对象轨迹预测算法。首先进行移动目标对象进行轨迹跟踪的控制对象描述和约束参量分析,对轨迹预测的大规模运动参量信息进行信息融合和自正整定性控制,通过大数据分析方法实现对移动对象运动参量的准确估计和检测,由此指导移动对象轨迹的准确预测,提高预测精度。仿真结果表明,采用该算法进行移动对象的运动参量估计和轨迹预测的精度较高,自适应性能较强,稳健性较好,相关的指标性能优于传统方法。     

Directly mapping whispering gallery modes in a microsphere through modal coupling and directional emission

We fabricate slightly deformed fused-silica microspheres in which whispering gallery modes possess remarkably directional escape emission from the microsphere boundary. With efficient flee-space excitation and collection, the lateral spatial distribution of whispering gallery modes with different azimuthal mode numbers, rn, is directly observed through modal coupling and directional emission. Excellent agreement with theory is obtained.     

利用高阶拉盖尔-高斯横模精确测量法布里-珀罗腔内原子的运动轨迹

研究了冷原子与法布里-珀罗腔内拉盖尔-高斯横模强耦合相互作用体系的透射光谱, 分析了透射光谱与原子在腔中运动轨迹的关系. 结果表明, 与厄米特-高斯横模相比, 拉盖尔-高斯横模的腔场与原子的最大耦合系数几乎不随阶数的增加而变化, 使得探测光谱的对比度受模式阶数的影响较小. 在拉盖尔-高斯横模场分布的圆环边缘附近, 原子运动轨迹的微小偏移会引起透射光谱的很大变化, 因此在这些位置可以实现原子运动轨迹的高精度探测.