Study of Layout Principle and Simulated Calculation for a Resonant Extraction System

Based on the general theory and related technique of 1/3 integer resonant extraction, main principle of layout for momentum-amplitude selection method is studied in detail and some simple analytic formulae are given. The design of slow extraction system for Beijing Proton Therapy Synchrotron (BPTS) is then given as an example by considering its lattice. The results are also compared with simulated calculation. Study shows that an extraction beam for BPTS with extraction efficiency above 98% and momentum spread of 0.11 % can be obtained.     

共振引出系统的布局研究和模拟计算

在介绍1/3整数共振引出基本理论和相关技术的同时,通过简明的解析公式,详细研究和分析了共振引出系统的布局原理.以一台小型医用质子同步加速器的磁铁聚焦结构为基础,给出了设计实例,并与计算机模拟结果进行了比较.     

图像式显微自动调焦、瞄准系统的研究

基于CCD图像技术提出一种新的图像式显微自动调焦、瞄准系统 ,该系统实现了通用光学仪器及现代数字化仪器中自动调焦与图像瞄准 ,解决了这类仪器自动化程度低 ,瞄准精度受人员主观影响大 ,劳动强度大 ,不易于微机化等问题。给出了新系统的结构与原理 ,分析了系统实现的精度保证 ,并对新系统进行了实验研究。     

Nonlinear fluctuation-dissipation relations and stochastic models in nonequilibrium thermodynamics: II. Kinetic potential and variational principles for nonlinear irreversible processes

On the basis of a complete system of fluctuation-dissipation relations, considered in the first part of this series, a variational principle for nonlinear irreversible processes is derived. According to this principle the virtual entropy production functional (analogous to the action in mechanics) has an absolute minimum meaning on the real trajectory of a system. The universal structure of the “kinetic potential” and the “lagrangian” of a system, each contain complete information about fluctuations of macrovariables. The connection of the lagrangian with the markovian kinetic operator of macrovariables is stated. Fundamental properties of dissipative potentials, reflecting microscopic reversibility, are considered. The derived variational principle can be applied to closed systems (the steady state of which is equilibrium) as well as to open ones (when external dynamic forces cause entropy flux through the system and put it into a steady non-equilibrium state). Canonical transformations of macrovariables are considered.     

A modification of the axiom system of quantum mechanics

A general axiom system, including both classical and quantum mechanics as special cases, is proposed. On the basis of the axioms assumed it is shown that the logic of experimentally verifiable propositions concerning any (classical or quantum) physical system may be embedded into an atomistic complete lattice. Moreover, in the quantum case (characterized in the paper by validity of the superposition principle) a generalization of the Piron's representation theorem for the logic is stated.     

基于二元光学的红外成像光谱仪离轴系统设计

对Lyons采用二元光学元件的红外成像光谱仪的设计理论进行了分析，为消除其二元光学元件作为透射式成像元件导致的焦距随波长的变化而变化的缺陷.提出将离轴三反射镜系统与具有二元光学透镜的变焦距系统相结合的新技术方案，并从军事目标的红外热探测的基本要求出发，给出了具体的设计实例.设计结果表明，系统具有设计精巧、结构简单、光能接收率高、消像差特性好、对材料的要求低以及满意的红外焦平面凝视阵列探测器的配准精度和探测精度.     

端口概念及应用的仿真演示实验

端口概念是微机原理及嵌入式系统相关课程中的关键概念之一。通过简单的设计实例,结合硬件原理和输入输出指令的执行时序,分析了端口的作用,端口地址的本质及形成过程。给出了Proteus环境下实验系统的仿真调试结果。     

Noether‘s theorem of a rotational relativistic variable mass system

Noether‘s theory of a rotational relativistic variable mass system is studied.Firstly,Jourdain‘s principle of the rotational relativistic variable mass system is given.Secondly,on the basis of the invariance of the Jourdain‘s principle under the infinitesimal transformations of groups,Noether‘s theorem and its inverse theorem of the rotational relativistic variable mass system are presented.Finally,an example is given to illustrate the application of the result.     

Gibbs光学双稳系统的状态反馈控制

基于稳定性理论,提出了一种状态反馈控制混沌的方法。介绍了该方法的控制原理以及各个预期的周期轨道反馈系数的选取原则。以Gibbs光学双稳系统为例,验证了该方法的有效性。数值结果表明,通过调节反馈系数,可以将系统控制在所需的目标轨道上。     

高能X射线基材料分解法基材料选择方法

选择基材料是高能双能X射线基材料分解法的重要环节。为了解基材料对材料识别精度的影响,确定选择基材料的方法和原则,利用美国国家标准与技术研究院（NIST）给出的材料的线性衰减系数,选择不同基材料,分析计算了各种待检测材料的原子序数和电子密度及相对误差。归纳总结出选取基材料的临近原则,即基材料与待检测材料的原子序数接近,能提高待检测材料原子序数和电子密度的分解计算精度。在此基础上,提出了四能基材料分解法。理论计算表明四能基材料分解法比双能基材料分解法对多种材料的整体识别精度更高,更适合用于多种材料同时存在情况下的识别与检测。运用蒙特卡罗方法模拟验证了四能基材料分解法用于实际的可行性。     

A study of multi-beam DICANNE system

I.IntroductionTheprob1cmofsuppressingstrongpointinterferencesourceisavcryimportantthesisinsonardesign.Fortheana1ogsonar,thesolutionofthisprob1emisquitedifficu1t.Untilthedevelopmentofdigitalsonar,thereissomerescarchreportsaboutsuppressingstrongpointin-terferencesource.Theear1ierworkin1969,dedicatcdbyV.C.Anderson,istheconccptofDICANNE(DigitalInterfcrcnceCance1lingAdaptiveNu1lNetworkEquipment)['l.Thisisadoublecompensatormulti-bcamsystcm.Oneisusedtoformintcrfercncebeamandanothcrisusedtofor…     

激光打标系统及工艺参数的分析

介绍了激光打标系统的结构,并以Nd：YAG振镜式激光打标机为例,分析其控制原理和计算机控制系统的扩展功能,并分别说明基于点阵扫描与矢量扫描两种方式对图形进行处理的打标方法。通过对标记机理和工艺过程的介绍,着重分析了工艺参数的选择对标记效果的影响。     

Equivalence principles exotica

This is a short review of the different principles of equivalence stated and used in the context of the gravitational interaction. We emphasize the need for precision in stating and differentiating these different equivalence principles, especially in the context of prevalent confusion regarding the applicability of the weak equivalence principle in quantum mechanics. We discuss several empirical results pertaining to the validity of the equivalence principle in exotic physical sitautions not directly amenable to experimental tests. We conclude with a section on the physical basis of the universal validity of the equivalence principle, as manifest in the universality of free fall, and discuss its link to cosmic gravity.      

高能X射线基材料分解法基材料选择方法

选择基材料是高能双能X射线基材料分解法的重要环节。为了解基材料对材料识别精度的影响,确定选择基材料的方法和原则,利用美国国家标准与技术研究院(NIST)给出的材料的线性衰减系数,选择不同基材料,分析计算了各种待检测材料的原子序数和电子密度及相对误差。归纳总结出选取基材料的"临近原则",即基材料与待检测材料的原子序数接近,能提高待检测材料原子序数和电子密度的分解计算精度。在此基础上,提出了四能基材料分解法。理论计算表明四能基材料分解法比双能基材料分解法对多种材料的整体识别精度更高,更适合用于多种材料同时存在情况下的识别与检测。运用蒙特卡罗方法模拟验证了四能基材料分解法用于实际的可行性。     

Non-smooth and time-varying systems of geometrically nonlinear beams

Bending vibrations of geometrically nonlinear beams, which are connected with some clearance in their contact areas, are analyzed during dynamic extending and retracting motion of the different segments. For the physical model of a fork lifter, as an example of application, the governing system equations are derived by applying Hamilton's principle. Using a discretization procedure, based on admissible shape functions, a system of coupled, nonlinear, time-varying, ordinary differential equations is generated. Linearization and model reduction leads to a sequence of simple models. On the basis of these models, an adaptive state regulator and an adaptive full-state observer (Luenberger Observer) are designed for vibration suppression using the optimal linear quadratic regulator (LQR). The adaptive controller and observer are applied to the original, significantly more complicated, geometrically nonlinear and time-varying system with clearance so that the robustness of the controlled system can be studied during dynamic extending and retracting motions.     

Concept for testing two-mirror optical telescopes

A concept for testing a two-mirror telescope optical system and its optical components is proposed. The example of the space ultraviolet Ritchey-Chretien telescope, with a primary mirror of 170 cm diameter, is considered. The principal propositions of the concept, and the optical schematic diagrams of the independent and mutual testing of the primary and secondary telescope mirrors, are discussed. Constructional data are presented of optical testing systems, with a minimum number of auxiliary optical elements of simple configuration. When designing the optical testing system, the principle of the null test method has been used. According to this principle the object to be tested and the auxiliary optical elements form a system that is free of aberration for a given kind of ray path. This makes it possible to use various methods and instruments intended for testing aberration free optical systems, for example, Twyman-Green and Fizeau interferometers, Foucault or knife edge test, and star tests^1–4.     

基于像散与理想光源成像原理的高亮度半导体激光器光纤耦合设计方法

运用像散原理和理想光源成像原理,讨论了半导体激光器消像散设计.提出了一种基于消像散的高亮度半导体激光器光纤耦合系统的设计方法.以波长为808 nm,输出功率为10 W的半导体激光器的光纤耦合为例,给出了详细的计算方法和设计步骤.结果表明:采用该方法将半导体激光器光束耦合入数值孔径为0.22,芯径为50 μm的光纤中,耦合后输出功率为9.712 W,耦合效率为97.12%,功率密度为1.1224×10⁶ W/cm².该方法不仅原理简单,而且设计的耦合系统耦合效率高、体积小,具有较强的实用价值.     

NOETHER'S THEOREM OF NONHOLONOMIC SYSTEMS OF NON-CHETAEV'S TYPE WITH UNILATERAL CONSTRAINTS

In this paper, we present Noether's theorem and its inverse theorem for nonholonomic systems of non-Chetaev's type with unilateral constraints. We present first the principle of Jourdain for the system and, on the basis of the invariance of the differential variational principle under the infinitesimal transformations of groups, we have established Noether's theory for the above systems. An example is given to illustrate the application of the result.     

MODELLING OF VIBRATING SYSTEMS USING TIME-DOMAIN FINITE ELEMENT METHOD

In this paper, several dynamic systems are modelled using the time-domain finite element method. Galerkin's weak principle is used to model the general second order mechanical system, and is applied to the dynamics of the simple pendulum. Problems that arise during the approximation of the final momentum are also investigated. Furthermore, additional dynamic analysis methods are suggested for hybrid co-ordinate systems that have both slew and flexible modes. The proposed methods are based on both extended Hamilton's principle and Galerkin's weak principle. The matrix wave equation is propagated in a space domain, satisfying the geometric/natural boundary conditions. As a result, the flexible motion can be obtained, and this was compatible with the applied control input. A numerical example is used to demonstrate the effectiveness of the proposed modelling methods for the hybrid co-ordinate systems.