Translational Motion of a Free Large Polaron and Broadening of Absorption Spectra

The translational motion of a large polaron as whole is analyzed in the context of its effect on the broadening of an absorption optical spectrum. It was open question how important the role of translational degrees of freedom and the corresponding velocities are on the broadening. The Bogolyubov method of canonical transformation of coordinates is formulated for a system of an electron and field, taking into account rigorous fulfillment of the conservation laws. Separation of variables is carried out for the coordinates describing the translational degrees of freedom and the electron oscillations in a polarization well. The equations obtained for the electronic states explicitly depend on the velocity of the free polaron as a whole. An estimate is made for free polaron in ammonia.

基于Leap Motion的手语识别算法优化

Leap Motion设备产生的数据在虚拟环境中可以进行手势识别。通过识别和跟踪用户的手来生成虚拟3D手部模型,从而获取手势信息。本文设计了一种基于隐马尔可夫模型(Hidden Markov Model,HMM)分类算法来学习从Leap Motion中所获取的手势信息的系统,根据手势特征的重要性赋予不同权值,可进一步提高分类准确率,实现手语信息的识别输入。测试结果表明,识别准确率为86.1%,手语打字输入识别速度为每分钟13.09个字符,可显著提高聋哑人与正常人之间沟通的便捷性。

Numerical study on wave loads and motions of two ships advancing in waves by using three-dimensional translating-pulsating source

A frequency domain analysis method based on the three-dimensional translating-pulsating （3DTP） source Green function is developed to investigate wave loads and free motions of two ships advancing on parallel course in waves. Two experiments are carried out respectively to mea- sure the wave loads and the free motions for a pair of side-by- side arranged ship models advancing with an identical speed in head regular waves. For comparison, each model is also tested alone. Predictions obtained by the present solution are found in favorable agreement with the model tests and are more accurate than the traditional method based on the three dimensional pulsating （3DP） source Green function. Numer- ical resonances and peak shift can be found in the 3DP pre- dictions, which result from the wave energy trapped in the gap between two ships and the extremely inhomogeneous wave load distribution on each hull. However, they can be eliminated by 3DTP, in which the speed affects the free sur- face and most of the wave energy can be escaped from the gap. Both the experiment and the present prediction show that hydrodynamic interaction effects on wave loads and free motions are significant. The present solver may serve as a validated tool to predict wave loads and motions of two ves- sels under replenishment at sea, and may help to evaluate the hydrodynamic interaction effects on the ships safety in replenishment operation.

The Translator's Subjectivity under George Steiner's Fourfold Translation Motion Theory-A Case Study on Lin Yutang's Translation of Fu Sheng Liu Ji

Since the advent of the cultural turn in translation studies in the 1970s, the focus of translation studies has been shifted to the subjectivity of translators. This paper attempts to make a tentative probe into the translator's subjectivity manifested in the translation of Fu Sheng Liu Ji by Shen Fu on the basis of George Steiner's fourfold translation motion theory, namely"trust", "aggression","incorporation"and"compensation". By the study, we may obtain scientific understanding of how the translation is shaped by the translator's subjectivity, thus affirming the importance and necessity of the later in literary translation.

Numerical Evaluation of Longitudinal Motions of Wigley Hulls Advancing in Waves by Using Bessho Form Translating-Pulsating Source Green's Function

In the framework of 3D potential flow theory, Bessho form translating-pulsating source Green's function in frequency domain is chosen as the integral kernel in this study and hybrid source-and-dipole distribution model of the boundary element method is applied to directly solve the velocity potential for advancing ship in regular waves. Numerical characteristics of the Green function show that the contribution of local-flow components to velocity potential is concentrated at the nearby source point area and the wave component dominates the magnitude of velocity potential in the far field. Two kinds of mathematical models, with or without local-flow components taken into account, are adopted to numerically calculate the longitudinal motions of Wigley hulls, which demonstrates the applicability of translating-pulsating source Green's function method for various ship forms. In addition, the mesh analysis of discrete surface is carried out from the perspective of ship-form characteristics. The study shows that the longitudinal motion results by the simplified model are somewhat greater than the experimental data in the resonant zone, and the model can be used as an effective tool to predict ship seakeeping properties. However, translating-pulsating source Green function method is only appropriate for the qualitative analysis of motion response in waves if the ship geometrical shape fails to satisfy the slender-body assumption.

Behaviors of cavitation bubbles driven by high-intensity ultrasound

In a multi-bubble system, the bubble behavior is modulated by the primary acoustic field and the secondary acoustic field. To explore the translational motion of bubbles in cavitation liquids containing high-concentration cavitation nuclei,evolutions of bubbles are recorded by a high-speed camera, and translational trajectories of several representative bubbles are traced. It is found that translational motion of bubbles is always accompanied by the fragmentation and coalescence of bubbles, and for bubbles smaller than 10 μm, the possibility of bubble coalescence is enhanced when the spacing of bubbles is less than 30 μm. The measured signals and their spectra show the presence of strong negative pressure, broadband noise,and various harmonics, which implies that multiple interactions of bubbles appear in the region of high-intensity cavitation.Due to the strong coupling effect, the interaction between bubbles is random. A simplified triple-bubble model is developed to explore the interaction patterns of bubbles affected by the surrounding bubbles. Patterns of bubble interaction, such as attraction, repulsion, stable spacing, and rebound of bubbles, can be predicted by the theoretical analysis, and the obtained results are in good agreement with experimental observations. Mass exchange between the liquid and bubbles as well as absorption in the cavitation nuclei also plays an important role in multi-bubble cavitation, which may account for the weakening of the radial oscillations of bubbles.

基于Leap Motion手语翻译器的设计与实现

手语翻译器作为不懂手语的正常人与使用手语的残障人士之间的沟通桥梁,近来成为研究热点,但是目前市场上成熟的手语翻译器并不多见。在此设计利用Leap Motion对手部识别精度高以及体积小巧等特性,实现了一种识别精度高、便于携带的手语翻译器。该翻译器不仅支持静态手语的识别,同时也能识别动态手语,实现了手语识别、文本翻译、语音播报,多语言翻译等功能。实验结果表明该手语翻译器具有识别准确率高的特点,能基本实现残障人士与正常人之间简单的交流,具有良好的应用前景。

天基逆合成孔径雷达脉内脉间运动补偿及高分辨成像

近年来,太空态势感知在军用和民用领域都得到了越来越多的关注。天基逆合成孔径雷达(SBISAR)能够实现对空间目标的高分辨成像,支撑部件提取、姿态估计、类型识别等后续任务,是太空态势感知的重要工具。然而,在SBISAR成像场景下,平台与空间机动目标间存在复杂的相对高速运动,传统距离-多普勒成像方法不再适用,必须进行运动补偿。本文针对高速径向速度下传统“停—走—停”模型失效、长相干积累时间内目标转速不一致的两个典型误差来源,分别设计了脉内运动及脉间运动补偿算法。首先,建立SBISAR成像的信号模型。然后,基于最小熵准则构建参数估计代价函数,通过估计目标对应回波信号的调频率,构造补偿项进而实现脉内补偿。同时,建立图像熵代价函数,在估计转动参数后,完成对目标转动的空变相位补偿。所提算法有效解决了天基高速机动背景下传统距离-多普勒成像方法的距离像展宽、方位散焦问题,实现了SBISAR对空间目标的高分辨成像。通过基于仿真数据的实验分析,验证了所提算法的有效性。

Using Pure Translation to Get Euclidean Reconstruction

A technique for getting Euclidean reconstruction from two images of the same scene taken by a single moving camera, which undergoes a pure translation, is presented. Euclidean reconstruction of the scene up to three scale factors can be obtained by using this special but still realistic motion when the skew factor of the cam- era is zero; otherwise Euclidean reconstruction of the depth up to one scale factor can be achieved. The only assumption is that the camera intrinsic parameters are constant. Using this special but still realistic motion to do the reconstruction has the advantage that no projective reconstruction is needed and the Euclidean reconstruction is computed directly from the point correspondences in the two images.

Measurement of six degree-of-freedom ground motion by using eight accelerometers

A new integrated measuring system with eight force-balance accelerometers is proposed to obtain a direct measurement of six degree-of freedom （DOF） ground motions, including three rotational and three actual translational acceleration components without gyroscopes. In the proposed measuring system, the relationship between the output from eight force-balance accelerometer and the six DOF motion of the measuring system under an earthquake are described by differential equations. These equations are derived from the positions and directions of the eight force-balance accelerometers in the measuring system. The third-order Runge-Kutta algorithm is used to guarantee the accuracy of the numerical calculation. All the algorithms used to compute the six DOF components of the ground motion are implemented in a real-time in Digital Signal Processor （DSP）. The distortion of the measured results caused by position and direction errors of the accelerometers in the measuring system are reduced by multiplying a compensation coefficient C to the output and subtracting static zero drift from the measured results, respectively.

A Study of Idiom Translation in Bonsall’s The Red Chamber Dream

This paper combines quantitative and qualitative methods to analyze the translation characteristics of idioms in B.S.Bonsall’s full English translation of The Red Chamber Dream,starting from George Steiner’s fourfold hermeneutic motion:trust,aggression,incorporation,and restitution.Through data statistics and conclusion analysis,I concluded that the translation strategies of idioms in Bonsall’s English translation are mainly literal translations,supplemented by free translations,and literal translations combined with free translations,which also provides some enlightenment for the English translation of Chinese classics.

平动条件下有限成坡土体挡土墙土压力分布规律研究

以河北腾龙露天矿止水固坡工程为背景,建立了挡土墙和有限成坡土体的三维数字模型,首先对模型的有效性进行了验证,然后利用该模型对平动条件下墙背上土压力分布规律进行数值模拟分析。结果表明,有限成坡土体滑裂面倾角随平台宽度增大先逐渐减小到零然后逐渐增大;平台宽度9 m时墙背上被动土压力数值解与解析解的变化规律基本一致,充分验证了该模型的有效性;被动土压力呈非线性分布,主动土压力呈凸曲线分布。综合考虑挡土墙稳定性与施工成本,建议将边坡坡角设为30°,平台宽度设为9 m。

基于GNSS全球解的地心运动反演方法

地心运动研究是实现毫米级坐标框架的重要内容。本文使用IGS服务重新处理后的、时间跨度为1995—2015年的周解数据,采用网平移法,利用HELMERT模型计算全球GNSS网络自由网解相对于ITRF成果的质心三维偏差时间序列,同时采用时间序列模型对地心运动3个方向的周年项特征(振幅和相位)进行了统计,并与SLR地心反演数据进行对比。结果表明,采用本文方法获取的基于IG2全球解的地心运动时间序列,在X、Y、Z 3个方向都含有周年项,其中Z方向周期运动更为显著;采用GNSS数据反演地心运动结果与SLR成果的总体特征一致性较好。

涡旋电磁波雷达平动旋转目标三维微动参数提取方法

与传统平面电磁波雷达相比,涡旋电磁波雷达能同时观测到目标投影到雷达径向和垂直于径向平面的微动分量,可为目标识别提供更多信息。当前关于涡旋电磁波雷达微多普勒效应的研究尚处于起步阶段,初步实现了对旋转目标的三维微动参数的提取,但均未考虑目标平动的影响。因此,该文研究了涡旋电磁波雷达中平动旋转目标的微多普勒效应,推导了平动旋转目标的角多普勒性质,提出了基于1/4微动周期多普勒频移曲线的三维微动参数提取方法,获得了目标旋转频率、旋转半径、旋转矢量和平动速度矢量等参数。仿真验证了角多普勒性质的正确性和参数提取方法的有效性。

动态场景下结合深度学习和平移约束的SLAM算法

针对在动态环境下,传统的同步定位与地图构建(simultaneous localization and mapping,SLAM)框架在动态物体上产生误匹配,导致计算结果不稳定的问题,提出了一种结合深度学习和平移约束的算法。首先,采用无监督的深度估计网络输出运动场信息,使用目标检测对训练数据进行预处理,以屏蔽场景静止部分对训练的干扰,同时,通过目标检测获得潜在运动对象,并与运动场信息联合判断该目标是否为运动对象。为了进一步剔除异常的匹配点,本文充分利用了直线行驶情况下的先验信息,通过灭点和匹配点对的约束关系,达到剔除异常匹配点的效果。结果表明:该方法较ORB-SLAM2在KITTI、TUM数据集上均方根误差分别降低了约16.38%、84.26%,与DynaSLAM相比降低了约6.65%、8.32%,同时较DynaSLAM效率也有所提升。

Effect of magnetic field on expansion of ferrofluid-encapsulated microbubble

Magnetic microbubbles(MMBs) have great potential applications in drug delivery and target therapy because they can be controlled by magnetic fields. In this paper, dynamic equations are derived by Lagrangian formalism and the behavior of MMBs subject to a combination field of magnetic and ultrasound field in an incompressible infinite fluid is analyzed numerically. The results show that the magnetic field can promote bubble expansion and hinder its translational motion,and both the enhancement and obstruction effects will weaken with the decrease of bubble size. The initial translational velocity has almost no effect on bubbles motion. Besides, the maximum expansion radius of MMBs increases with the ferrofluid shell thickness, while that of the common MBs is just the opposite. In addition, the periodic change of Levich viscous drag caused by the rebound leads to the step-like translational motion. Finally, the ferrofluid-shell model can be replaced by the model of non-magnetic microbubbles in magnetic liquid at high driving frequency.

侧限条件下密实砂土蠕变的颗粒运动特征

任何构筑物长久安全稳定的重要性使得土的时间效应成为该领域学者最为关心的问题之一。基于3D打印杆件的等效砂土颗粒,通过侧限条件下的蠕变试验,采用近景摄影测量与粒子图像测速(particle image velocimetry,简称PIV)技术,从单颗粒运动与颗粒间接触运动的角度出发,探究密实砂土蠕变的内部颗粒运动特征及其与宏观蠕变变形的关系。试验结果表明,3D打印杆件能够很好地反映密实砂土蠕变的宏观变形特性,侧限条件下蠕变变形随时间的增加而增加,随蠕变应力的增加而减小,蠕变变形呈现出蠕变速率减小并趋于稳定的初始蠕变阶段与稳态蠕变阶段。其原因为蠕变最初阶段颗粒整体向下平动,并发生较大转动,颗粒间孔隙明显减小,蠕变变形主要由颗粒间孔隙的压密提供;而后颗粒间孔隙减小不明显,趋于稳定,颗粒发生不规则方向平动,蠕变变形主要由局部的颗粒位置调整与重排列控制,揭示了宏观的蠕变变形与微观的颗粒平动变化有着密切联系。颗粒间的接触运动随着蠕变时间的增加而明显增大。蠕变过程中,接触滚动和接触滑动同时发生,并逐渐集中在某些易发生移动的接触点上。强运动接触点的平均滑动距离与平均滚动距离存在着良好的线性关系,随着时间的增加,平均滑动距离逐渐大于平均滚动距离,表明颗粒间滑动产生体积收缩,控制宏观蠕变变形。

Rigid-Liquid-Flexible Dynamic Formulation for a Two-Dimensional Tank Undergoing Translational and Rotational Motion

Considering rigid-liquid-flexible coupling effect, dynamic formulation for a two-dimensional rectangular tank with liquid sloshing connected to a flexible beam is proposed. Differing from the traditional formulation which considered either the rotational motion or the translational motion of the tank, this formulation can be applied for rigid-liquid-flexible coupling dynamic analysis of tank undergoing translational and rotational motion based on the theorem of momentum and the theorem of moment of momentum. Furthermore, stiffening terms are included in the dynamics equations of the flexible beam. Firstly, the dynamic equations of the rigid-liquid coupling system and the flexible beam are derived, respectively, and then by introducing the Lagrange-multipliers,the rigid-liquid-flexible coupling equations can be combined with acceleration constraint equations. Finally, the mix differential-algebraic equations are solved to investigate the rigid-liquid-flexible coupling dynamic performance of the system.

Decomposition of Molecular Motions into Translational, Rotational, and Intramolecular Parts by a Projection Operator Technique

The motion of the atoms in a molecule may be described as a superposition of translational motion of the molecular center-of-mass,rotational motion about the principal molecular axes,and an intramolecular motion that may be associated with vibrations and librations as well as molecular conformational changes.We have constructed projection operators that use the atomic coordinates and velocities at any two times,t=0 and a later time t,to determine the molecular center-of-mass,rotational,and intramolecular motions in a molecular dynamics simulation.This model-independent technique facilitates characterization of the atomic motions within a system of complex molecules and is important for the interpretation of experiments that rely on time correlation functions of atomic and molecular positions and velocities.The application of the projection operator technique is illustrated for the inelastic neutron scattering functions and for the translational and rotational velocity autocorrelation functions.

斯坦纳阐释学翻译理论视角下中国古典哲学术语英译研究——以陈荣捷译《传习录》为例

王阳明是中国明代著名哲学家,阳明心学的集大成者。而《传习录》汇集了王阳明与其弟子和友人的部分书信和语录,是中国古典哲学的重要典籍。因此,《传习录》里中国古典哲学术语的英译具有重要的研究价值。陈荣捷致力于中国古典哲学文献英译事业,该文以陈荣捷《传习录》的英译为例,在乔治·斯坦纳的阐释学四步骤翻译理论的视角下,归纳总结中国古典哲学术语的翻译方法和策略。通过对陈荣捷英译《传习录》的研究和总结,该文认为乔治·斯坦纳阐释学四步骤翻译理论适用于中国古典哲学术语的翻译。期望该文能为未来的哲学翻译研究提供有益的借鉴与参考。