西派集团 气动偏心旋转阀

气动偏心旋转阀主要由阀体组件和气动执行机构组成。其中阀体组件由阀体、球面阀芯、阀座、阀杆、摇臂和填料这几个主要部分组成。其阀芯的中心偏离转轴的中心，当转轴在旋转的同时．阀芯相对阀体中心线做了凸轮状偏心旋转．并且依靠阀芯柔臂的弹性来变形．使得阀芯球面与阀座紧密接触时达到可靠密封。     

西派集团气动偏心旋转阀

气动偏心旋转阀主要由阀体组件和气动执行机构组成。其中阀体组件由阀体、球面阀芯、阀座、阀杆、摇臂和填料这几个主要部分组成。其阀芯的中心偏离转轴的中心．当转轴在旋转的同时．阀芯相对阀体中心线做了凸轮状偏心旋转．并且依靠阀芯柔臂的弹性来变形，使得阀芯球面与阀座紧密接触时达到可靠密封。     

基于人工神经网络-遗传算法的展成法球面精密磨削 参数优化

航空制造业的迅速发展对球面磨削加工精度提出了更高的要求，国内目前广泛依靠加工者经验选取磨削参数，工件球面轮廓度最高仅为2.2μm。为实现球面高精度加工，针对GCr15材料柱塞零件的展成法球面磨削加工，提出一种可靠的工艺参数优化方法。以砂轮速度、工件转速、进给速度为影响因素，以磨削后球面轮廓度和磨削加工时间为目标函数，设计了正交试验，分析了各磨削参数对球面轮廓度的影响程度。考虑到各磨削参数和球面轮廓度之间关系的复杂性，在正交试验的基础上利用遗传算法优化的BP（back propagation，反向传播）人工神经网络建立了球面轮廓度和各磨削参数之间的非线性映射关系，并进一步利用遗传算法进行极值寻优，得到最优的磨削参数组合。最后，根据最优磨削参数组合进行了多组验证实验。结果表明，使用优化后的磨削参数能够在保证加工效率的前提下将工件球面轮廓度提高到1.4μm，较传统经验法提高了36%。所提出的磨削参数优化方法可靠、有效，可直接应用于实际工程，对实现球面精密加工意义显著。     

基于五轴数控加工的球面铣削研究

本文研究了高精度球面加工的方法,阐述五轴加工方案的特点,着重研究五轴机床在球面加工上的相关方法及技术。     

进给系统刚度对内球面车削的误差影响研究

针对目前半闭环车床加工内球面精度低、误差大的现状,研究进给系统刚度对加工误差的影响并提高内球面的加工精度.利用赫兹接触理论对进给系统刚度进行分析,建立了刚度的数学模型．分析了半闭环车床加工内球面的工艺过程,并推导了切削曲面过程中进给系统受力状况,给出了误差表达式．通过对加工误差模型的仿真研究,结果表明进给系统刚度所产生的加工误差与刀位点和母线圆弧形状有关,所产生的误差可通过增发运动脉冲补偿．提出了一种引进补偿机制的插补运算方法,为提高内球面加工精度提供了理论上的指导．     

应力抛光技术实验装置的研究

基于弹性力学理论的应力抛光技术(SMP)是将非球面加工转化为球面加工的新技术,能够有效地提高非球面加工效率.由应力抛光技术的算法及有限元分析、模拟,针对玻璃材料自身的性质以及在球面镜周边施力或力矩来实现球面到非球面之间变形量的要求,设计、加工和装调一套专门用于应力抛光技术的实验装置,为了实现应力抛光技术中玻璃薄板的球面到抛物面之间的变形,以该装置加工了一块口径为Φ314 mm,F/7的抛物面镜为例,抛光结束的抛物面其峰值(PV)为3.317λ,均方根(rms)为0.489λ,验证了应力抛光技术实验装置的合理性和有效性.     

圆柱表面微结构阵列超精密车削加工技术

辊子是光学薄膜模压制造的关键零件,其圆柱表面微结构复杂,表面粗糙度要求也极高.超精密车削成形作为微结构的一种高效加工方式,其加工的可达性、伺服刀具动态特性的制约、海量微结构的加工长时一致性等是高质量辊子微结构加工所需解决的关键问题.本文以圆柱球面微结构阵列为例,从其数学描述入手,分析了刀具几何尺寸、伺服系统动态特性与微结构加工可达性之间的制约关系,并在自主研制的超精密车床和快刀伺服系统上进行了两种球面微结构的加工实验,得到了预期的微结构形貌,并对加工实验中发现的切深不一致现象给出了初步的解释.     

基于均匀化方法的离子推力器栅极组件的有限元分析计算

离子光学系统是离子火箭发动机推力器中装配要求最严格的部件之一,其性能的好坏直接影响推力器的性能。栅极是离子光学系统的主要组件,其结构为多孔球面薄板。基于均匀化方法利用ANSYS有限元软件建立了球面栅极组件的有限元模型,分别进行了栅极组件的模态分析和均布载荷下的位移、谐响应分析,为设计、加工和装配提供可靠的数据。     

球面插值PH曲线

本文讨论球面上PH曲线的C1Hermite插值问题。基于球极投影保持PH性质这一特性,通过球极投影把球面数据投影到平面上,构造一条平面PH曲线。然后,逆投影回球面得到一条球面有理插值PH曲线。球面PH曲线对球面数据达到C1插值,拓宽了PH曲线在机器人路径的设计、数控加工的计算等方面的应用范围。     

不锈钢半球面的超精加工技术及其检测方法

应用光学冷加工的工艺方法和检测技术,制造了用于气体静压球面轴承的高精度不锈铜半球面——凹球面球座(半径为62.77毫米)和凸球面球轴(半径为62.76毫米)。实测结果表明:凸凹半球的截面不圆度小于0.2微米,表面光洁度为▽14a(R_2<0.05微米),球座球轴的球面半径加工误差小于3微米。     

Light scattering by a coated sphere illuminated with a Gaussian beam

The intensity of light scattered by a coated sphere illuminated with an off-axis Gaussian beam is calculated. Results are shown for different beam positions with respect to the sphere. As the beam is shifted further away from the surface of the sphere, the higher-Q morphology-dependent resonances become increasingly important in the backscatter spectra, and the angular scattering intensity becomes smoother.

The scattered intensity depends on the beam position, the refractive indices of the core and coat, the radius of the core, and the thickness of the coat. As the beam is moved further away from the sphere, the effect of the core on the scattering intensity decreases. When the incident Gaussian beam is focused outside of a particle with a relatively small core, the scattering spectra and angular scattering patterns become similar to those of a homogeneous sphere having the refractive index of the coat. These calculated results suggest that measurements of spectral scattering and angular scattering patterns for several Gaussian beam positions could be useful for the characterization of coated spheres.

     

Vibration analysis of a poroelastic composite hollow sphere

Vibrations in a poroelastic composite hollow sphere are investigated employing Biot’s theory of wave propagation in poroelastic media. A composite hollow poroelastic sphere consists of two concentric poroelastic spherical layers both of which are made of different poroelastic materials with each poroelastic material being homogeneous and isotropic. The boundaries of the composite hollow poroelastic sphere are free from stress. The frequency equations of both radial and rotatory vibrations are obtained each for pervious and impervious surfaces. The frequency equation of vibrations of a poroelastic composite hollow sphere with rigid core is derived as a particular case. The non-dimensional frequency for propagating modes is computed as a function of ratio of thickness to inner radius of core. The results are presented graphically for two types of poroelastic composite spheres and then discussed.     

Electromagnetic Resonance at the Interface of Two Concentric Spheres

Abstract

Some results of a theoretical study on the interaction of an electromagnetic plane wave with a coated sphere are presented. The finely stratified sphere model (Kai, L., and Massoli, P. 1994, Appl. Optics, 33 501) is used for numerical calculations. It is found that when the refractive index of the core is larger than the refractive index of the coating, the Q _ext-x spectrum for a coated sphere differs from the spectrum of a homogeneous sphere by having both sharp minima and sharp maxima, all corresponding to strong electromagnetic resonances at the interface of the core and the coating.     

Preparation and characterization of optical-functional diblock copolymer brushes on hollow sphere surface via atom transfer radical polymerization

The optical-functional poly(methyl methacrylate)-block-Tb complex diblock copolymer brushes grafted from hollow sphere surface via atom transfer radical polymerization were investigated in this work. A sufficient amount of azo initiator was introduced onto hollow sphere surface firstly. Then the monomer methyl methacrylate was polymerized via surface-initiated reverse atom transfer radical polymerization using azo group modified hollow sphere as initiator. Following, the poly(methyl methacrylate) modified hollow sphere was used as maroinitiator for surface-initiated atom transfer radical polymerization of Tb complex. The samples were characterized by Fourier transform infrared spectroscopy, hydrogen nuclear magnetic resonance, gel permeation chromatographer and transmission electron microscopy, respectively. The results indicated that the poly(methyl methacrylate) had grafted from hollow sphere surface and the average diameter of hollow core was about 1 μm. The optical properties of the poly(methyl methacrylate)-block-Tb copolymer modified hollow sphere were also reported.     

Preparation of tungsten carbide porous sphere core wrapped by porous multiwall

Tungsten carbide porous sphere core wrapped by porous multiwall was prepared by spray drying sphere miniaturation—gas–solid reaction, used ammonium metatungstate as precursors, hydrogen and methane as reduction and carbonization atmosphere. The sample was characterized by SEM, XRD and BET, respectively. The SEM results show that the sample is constituted by two parts, a core with porosity and porous multiwall, and the wall is made up of a lot of nanoscale particles. The XRD results show that the crystal phase of the sample is tungsten carbide (WC) only, and the average size of the WC crystal estimated according to XRD data is around 14 nm. The BET specific area of the sample is 10.2834 m²/g.     

Laser drilling of hollow sphere structures

A special composite and cellular material – the metallic hollow sphere structure (MHSS) – represents an advanced material. The core element of the structure is a hollow sphere with a wall out of porous steel. This shell allows a high geometric reproducibility. It is an interesting base material for lightweight design. However, processing technologies for further manufacturing of metallic hollow sphere structure are necessary. Laser beam drilling is a highly efficient technique with heat input concentrated locally at the structure. Laser drilling is applied to metallic hollow sphere structures. The influence of different geometries and joining technologies of the spheres on the drilling behaviour is investigated. Percussion drilling is used to form holes with a CO₂‐laser into the metallic hollow sphere structure. The investigated mean laser power is 400 W. Two different focal lenses with focal lengths of 5″ and 7.5″ allow investigations with different focal diameters and Rayleigh lengths. Diameter and roundness of the laser drilled holes are measured in five layers of different drill depths z. The maximum drilled depth is about 40 mm with a 5″ lense and about 50 mm with the f = 7.5″ lens. The relative roundness is determined and decreases with increasing drill depth. The diameter d(z) as a function of the drill depth follows the shape of an isophote, a line of constant intensity inside the laser beam. The brazed hollow sphere structures have considerably less drill depth than the sintered.     

Experimental analysis of the flexural properties of sandwich panels with cellular core materials

This paper addresses the flexural properties of sandwich structures with cellular core materials. Experimental three point bending tests are conducted in order to determine the flexural stiffness and the load‐carrying capacity of these advanced composites. In addition, the significant failure modes after exceeding the load‐carrying capacity are identified. The results of these analyses are compared for sandwich structures containing various core materials. These core materials comprise two aluminium foams, namely M‐Pore® and Alporas®, honeycomb structures and novel metallic hollow sphere structures (MHSS).     

基于扫掠球量的快速距离计算

引入扫掠球量作为包围量.扫掠球是一系列相对于核基本形状以某一等距向外扩展而形成的包围量.核基本形状包括点,线段和矩形.这些包围量可以提供对被包围物体的不同的紧密性.基于这些包围量,建立混合层次并且采用有效而准确的算法可以计算两物体之间的距离,并可通过在返回值中引入相对误差来进一步提高算法效率.     

Certain peoblems relating to the regular thermal regime of bicomponent materials

We have derived equations — convenient for practical application — describing the regular thermal regime of a plate, a sphere, and a cylinder, with a finite value for the heat-transfer coefficient when the heat capacity of the core is greater than or equal to the heat capacity of the shell.     

Highly emissive nano rod-in-rod heterostructures with strong linear polarization

We report the synthesis of CdSe/CdS rod in rod core/shell heterostructures. These rods, synthesized using a seeded-growth approach, show narrow distributions of rod diameters and lengths and exhibit high emission quantum efficiencies and highly polarized emission. The degree of polarization is controlled by the inner core rod dimensions, and it is equal or up to 1.5 times higher than the polarization of equivalent sphere in rod systems. Using the method of photoselection we measure the polarization anisotropy at different excitation wavelengths and study the interplay between electronic contribution and dielectric effects in determining the absorption and emission polarization.