Radiative corrections and the sliding singlet mechanism for light doublet Higgs fields

We demonstrate that the sliding singlet mechanism for keeping the doublet Higgs components light is influenced by the radiative effects of spontaneous breaking of global supersymmetry induced by a still unobserved field. An upper limit on the mass of this field arises.     

运输机重装空投二阶终端滑模控制方法研究

针对重装空投过程中,货物的持续移动及瞬间出舱影响空投任务完成性、威胁飞行安全等问题,提出了一种二阶终端滑模纵向飞行控制方法;该方法利用非线性多输入多输出反馈线性化完成系统解耦线性化,在此基础上采用二阶终端滑模变结构控制设计系统内环速度与俯仰姿态跟踪控制器,保证了系统鲁棒性,结合外环PID高度保持控制器完成了整个飞行控制系统的设计;数值仿真结果表明,该系统具有良好的响应特性,且对系统不确定性具有较强的鲁棒性。     

Lasing in liquid crystal thin films

A lasing condition is formulated in matrix form for optically anisotropic thin films. Lasing behavior of liquid-crystal slabs is analyzed. In particular, it is shown that if the spatial extent of a liquid crystal slab is much larger than its thickness, then laser emission is feasible not only along the normal to the slab, but also in the entire angular sector. The generated laser light can be observed experimentally as a spot or as concentric rings on a screen. The lowest lasing threshold corresponds to in-plane sliding modes leaking into the substrate. The feedback required for lasing is provided by reflection from the interfaces, rather than edges, of the liquid-crystal slab operating as a planar Fabry-Perot cavity. For cholesteric liquid crystals, it is shown that energy loss to the sliding modes leaking into the substrates and escaping through their edges is a key factor that limits the efficiency of band-edge emission along the normal to the slab.     

Departures from Amonton's law of friction

The method of transition from light friction (rolling) to heavy friction (sliding) is used for analyzing the principal departure from Amonton's law (force of sliding friction T proportional to the normal pressure force N) for several metal — nonmetal pairs when the sliding time t approaches zero. It appears that the departure mode is, under these conditions, the same for all pairs which have been tested here. Experimental and theoretical evidence is given to prove that all other modes of departure from Amonton's law represent consequences of changes in the rubbing surfaces which occur during sliding and that, therefore, such departures will appear only after a long enough period of sliding.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 94–98, November, 1974.     

脉冲电流波形对固体电枢滑行性能的影响

利用一种小型脉冲功率系统的脉冲形成网络进行波形调制,得到了锯齿、凸顶和平顶脉冲电流波形,利用这三种脉冲电流开展了导轨型电磁驱动系统中的固体电枢滑行实验,通过测量电枢极限出口速度,比较了不同脉冲电流波形对固体电枢滑行性能的影响。结果表明:电流变化急剧的锯齿波形在较低的充放电能量下就会引起固体电枢与导轨界面接触失效,发生烧蚀现象,因而不利于固体电枢的滑行; 相同充放电能量条件下,凸顶波形比平顶波形得到的固体电枢出口测速高,即效率更好; 平顶波形可使固体电枢承受更高的充放电能量,且平顶波形比凸顶波形的极限出口测速高; 三者相比,平顶波形最有利于固体电枢与导轨良好接触,电枢的滑行性能表现得最好。     

Ghost imaging and ghost interference with pseudo-thermal light: Mode-separation by pure software processing

We report on a new experiment in which ghost imaging and ghost interference with quasi-thermal light are simultaneously obtained from the same set of experimental reference patterns. By sliding the mask along the object arm in a continuous way, one can see imaging and diffraction patterns to come to light and fade out in opposite directions.     

Stimulation and Suppression of Grain Boundary Sliding by Intragranular Slip in Zinc Bicrystals

The influence of intragranular slip on grain boundary sliding is studied in originally compatible zinc bicrystals with symmetric tilt boundary. The experiment is designed to separate different effects of intragranular slip on the boundary sliding and establish their mechanisms. Grain boundary sliding with and without development of intragranular slip is observed. The rate of sliding accompanied by slip is more than five times of that without slip. A good correlation between the boundary sliding and intragranular slip prior to slide hardening is established. Slide hardening followed by the negative sliding near one end of the boundary and strain hardening in the boundary vicinity, are observed at the last stages of deformation. For the case of formation of slip induced glissile grain boundary dislocations of opposite signs the possibility of their contribution to total grain boundary sliding, is analyzed. The effect of the increase in the rate of sliding is explained in terms of the accommodation of sliding by slip and appearance of additional glissile grain boundary dislocations of one sign due to strain incompatibility. Contribution of these different dislocation mechanisms to the increase in the sliding rate is determined for the stage of deformation preceding slide hardening. It is supposed that the effect of slide hardening and negative sliding as well as boundary curving is created by non-smooth boundary and small degree of incompatibility caused by straining.     

Physical mesomechanics of grain boundary sliding in a deformable polycrystal

The temperature-rate dependences of strain resistance and the mechanisms of grain boundary sliding in Pb polycrystals and Pb-based alloys under active tension were investigated. The activation energy of plastic deformation and grain boundary sliding was determined. The structural mechanisms of grain boundary sliding were studied in a wide temperature range. The conclusion was made that self-consistency of grain boundary sliding and intragranular plastic flow has its origin in rotational deformation modes, with the grain boundary sliding being a primary process. Theoretical analysis of rotational deformation modes involved in grain boundary sliding was performed. It is shown that the dependence of deforming stress on the polycrystal grain size is impossible to describe by one universal Hall-Petch equation.     

Optical-feedback induced chaos and its control in semiconductor lasers based on sliding tunable dual-wedges

We present a method of chaos and its control in semiconductor laser based on sliding tunable dual-wedges. We numerically reveal the dynamics of chaos and its control in semiconductor lasers by changing the length of sliding tuneable dual-wedges. The results indicated that, with the appropriate changes of the length of sliding tuneable dual-wedge, the laser can be controlled into steady state, single-periodic, multi-periodic and even chaos respectively. The results also provide a new method to generate various period states in the chaos system.     

Dynamic aeroelastic response and active control of composite thin-walled beam structures in compressible flow

The dynamic aeroelastic response and its active control of composite beam structures in compressible flow and exposed to gust and explosive type loads are examined. Modeling of the structures is based on a refined composite thin-walled beam theory and incorporate a number of nonclassical effects, such as transverse shear, material anisotropy, warping inhibition, and rotatory inertia. The unsteady compressible aerodynamic loads for arbitrary small motion in the time domain are derived based on the concept of indicial functions. The sliding mode control (SMC) and linear-quadratic Gaussian (LQG) control methodology with sliding mode observer are used for the purpose of control. The beam structures are restricted to circumferentially asymmetric lay-up construction and the influence of ply angle, flight speed, and external excitations on the response and its active control are specifically investigated. A number of conclusions are outlined at the end.     

掺硅类金刚石薄膜摩擦过程的分子动力学模拟

掺硅类金刚石(Si-DLC) 薄膜表现出优异的摩擦学性能, 在潮湿空气和高温中显示出极低的摩擦系数和很好的耐磨性, 但是许多实验表明Si-DLC膜的摩擦性能受其硅含量的影响很大. 因此, 本文采用分子动力学模拟的方法分别研究干摩擦和油润滑两种情况下不同硅含量的Si-DLC膜的摩擦过程. 滑移结果表明干摩擦时DLC膜和掺硅DLC膜之间生成了一层转移膜, 而油润滑时则为边界膜. 因此干摩擦时的摩擦力明显大于油润滑时的摩擦力. 少量添加硅确实能降低DLC膜的摩擦力, 但是硅含量大于20%后对DLC膜的摩擦行为几乎无影响. 干摩擦时硅含量对转移膜内键的数量影响很大, 转移膜内CC键和CSi键都先增加后减少, 滑移结束时几乎不含CSi键.     

3 GPa熔融盐固体介质三轴高温压力容器的轴压摩擦力标定

 在温度标定和围压标定的基础上,采用轴压循环方法,对3 GPa固体介质三轴高温高压实验系统的轴压摩擦力进行了标定,分析了围压、温度、轴向位移速率、装样方式（盐套类型）等实验条件对轴压摩擦力的影响。结果表明：静摩擦力、挤压摩擦力和滑动摩擦力3种轴压摩擦力对轴向应力的影响不同,其中静摩擦力和挤压摩擦力对轴向应力的影响很小,影响应力精度的主要是滑动摩擦力。静摩擦力及滑动摩擦力与围压正相关;静摩擦力与轴向位移速率正相关,但受其影响较小,滑动摩擦力不受其影响;静摩擦力和滑动摩擦力与温度负相关,并且受其影响较显著;盐套类型对轴压摩擦力的影响较大,当实验条件接近盐套熔点时,轴压摩擦力显著降低,当样品周围的盐套处于熔融状态时,轴压摩擦力最小。基于此,确定了标定轴压摩擦力的具体步骤,并对角闪岩的应力-应变曲线进行了轴压摩擦力标定。对比轴压摩擦力校正前、后的应力-应变曲线发现,经过轴压摩擦力校正的应力-应变曲线能更好地反映样品的实际变形情况。     

Chaotic rocking behavior of freestanding objects with sliding motion

This paper examines the influence of effects of sliding on the non-linear rocking response behavior of freestanding rigid objects (blocks) subjected to harmonic horizontal and vertical excitations. It is well known that the rocking responses depend strongly on the impact effect between object and the base, which takes place with abrupt reduction in kinetic energy. In this study, it is shown that the rocking behavior is significantly affected by the presence of the sliding motion. A parametric response analysis is carried out over a range of excitation amplitudes and frequencies. Chaotic responses are observed over a wide response region, particularly for the case of large vertical amplitude excitation with significant sliding motions. The chaotic characteristics are demonstrated using time histories, Poincaré sections, power spectral density and Lyapunov exponents of the rocking responses. The complex chaotic response behavior is illustrated by Poincaré section in the phase space. The distribution of various types of rocking responses and the effects of sliding motion are examined via bifurcation diagrams and examples of typical rocking responses.     

一个新的分数阶混沌系统的翼倍增及滑模同步

首先,提出了一个新的分数阶混沌系统,通过对系统第二个等式的线性项x作绝对值运算,并分析了其唯一的参数k,该参数在一定区间内取值时可将混沌吸引子由两个翼的结构变换为四翼的拓扑结构,从而实现翼倍增. 其次,分别采用Matlab和Multisim对新的分数阶系统及其翼倍增系统进行了数值模拟和电路仿真,电路仿真结果和数值模拟结果相一致. 最后,基于滑模变结构控制理论和分数阶稳定性定理,为新的分数阶系统及其翼倍增系统设计了新的分数阶积分滑模控制器实现系统的同步,仿真结果和理论分析相一致,证实了所设计滑模控制器的有效性. 关键词： 分数阶 翼倍增 滑模控制 同步     

Frictional coupling between sliding and spinning motion

The tangential motion at the contact of two solid objects is studied. It consists of a sliding and a spinning degree of freedom (no rolling). We show that the friction force and torque are inherently coupled. As a simple test system, a sliding and spinning disk on a horizontal flat surface is considered. We calculate, and also measure, how the disk slows down and find that it always stops its sliding and spinning motion at the same moment. We discuss the impact of this coupling between friction force and torque on the physics of granular materials.     

Sliding in a piecewise-smooth dynamical system with a hold-on effect

In this paper, we study a piecewise-smooth dynamical system of a Filippov type that has a specific discontinuity in the form of a hold-on term. The system resembles a driven dry-friction oscillator with the difference that the magnitude of the friction depends on the value of a local maximum of the oscillator displacement. Due to the hold-on term, the definition of the sliding region is not trivial. Along with a sliding region that is found analytically and is valid for any orbits, there exists a sliding region that we name ‘virtual’ because it is specific for each particular orbit. The existence of the virtual sliding region is explained by the specific discontinuity — the hold-on term — and the behavior associated with the sliding region and its boundaries can be considered as a new type of sliding-associated behavior.     

摩擦导致的聚合物表层微观结构改变

应用大规模分子动力学方法, 模拟了锥形探头在非晶态聚合物薄膜表面的滑动摩擦过程, 研究了摩擦导致的聚合物薄膜表层微观结构改变, 以及探头与基体间黏着作用、滑动速度和分子链长度对基体表层微观结构改变的影响. 当探头与基体之间为黏着作用时, 摩擦导致基体表面滑痕区域的键取向沿滑动方向重新取向, 导致表层分子链回转半径沿滑动方向伸长, 并且这些表层微观结构的改变程度随滑动速度的减小而增大. 在摩擦导致结构改变的过程中, 链端单体和链中单体的贡献作用不同, 形成了不同的分子链拉伸变形机制. 当样本缠结度较大或探头滑动速度较小时, 相比于链中单体, 探头对链端单体的拖曳作用使更多分子链发生拉伸变形. 研究还发现, 在探头与聚合物薄膜系统中, 使薄膜表层微观结构发生改变是摩擦能量耗散的重要途径.     

Filtering of Trends with Forbush Effects of Time Series of Observations Performed by Cosmic-Ray Monitoring Systems

A method for filtering trends with Forbush effects of the time series of observations performed by cosmic-ray monitoring systems is proposed. A filtering algorithm based on sliding local models and weighted averaging is developed. A mathematical technique for optimizing the filter parameters is implemented. The results of observations from a neutron monitor are used as an example to test the developed filtering algorithm and estimate its efficiency.     

双缝光幕靶设计

针对动力源火工品速度测试，设计了一种双缝光幕靶，实现对低速运动的火工品零件测速。与常规的单缝光幕靶不同，文中设计的双缝光幕靶将2个发射和接收装置融进一个单体结构，形成2个光幕。2台双缝光幕靶安装在同一个带有滑轨的固定架上，靶距可以任意调节。设计的双缝光幕靶可以替代传统的铜片测速方法，有效地提高了测量精度和实现了测量自动化。经过实弹射击和火工品试验验证，设计的双缝光幕靶测试系统可靠，测试数据准确。     

Nonsingular terminal sliding mode approach applied to synchronize chaotic systems with unknown parameters and nonlinear inputs

This paper deals with the design of a novel nonsingular terminal sliding mode controller for finite-time synchronization of two different chaotic systems with fully unknown parameters and nonlinear inputs.We propose a novel nonsingular terminal sliding surface and prove its finite-time convergence to zero.We assume that both the master’s and the slave’s system parameters are unknown in advance.Proper adaptation laws are derived to tackle the unknown parameters.An adaptive sliding mode control law is designed to ensure the existence of the sliding mode in finite time.We prove that both reaching and sliding mode phases are stable in finite time.An estimation of convergence time is given.Two illustrative examples show the effectiveness and usefulness of the proposed technique.It is worthwhile noticing that the introduced nonsingular terminal sliding mode can be applied to a wide variety of nonlinear control problems.