New design of spherical multilayered pressure vessels

The article presents the results of theoretical and experimental investigations of the serviceability of a new design of multilayered large pressure vessels envisaging their assembly at the erection site.Translated from Problemy Prochnosti, No. 12, pp. 44–48, December, 1990.     

正交设计在单分散球形SiO2制备中的研究

用正交试验,采用L9 (33)正交表,在醇水体系中采用氨作催化剂,正硅酸乙酯为硅源,研究了各原料浓度对单分散球形SiO2 粒度的影响。研究表明在其它条件不变的情况下,二氧化硅的粒度随着氨和水浓度的增加而明显增大,随TEOS 浓度的增加,二氧化硅的粒度也略有增大,但幅度较小。本文还详细研究了二氧化硅颗粒的形成机理。     

Morphology-dependent resonances of nearly spherical particles in random orientation

We use precise T-matrix calculations for prolate and oblate spheroids, Chebyshev particles, and spheres cut by a plane to study the evolution of Lorenz-Mie morphology-dependent resonances (MDRs) with increasing asphericity of nearly spherical particles in random orientation. We show that, in the case of spheroids and Chebyshev particles, the deformation of a sphere by as little as one hundredth of a wavelength essentially annihilates supernarrow MDRs, whereas significantly larger asphericities are needed to suppress broader resonance features. The MDR position and profile are also affected when the deviation of the particle shape is increased from that of a perfect sphere. In the case of a sphere cut by a plane, the supernarrow MDRs are much more resistant to an increase in asphericity and do not change their position and profile. These findings are consistent with the widely accepted physical interpretation of the Lorenz-Mie MDRs.     

可实现三维位置检测的球型电机磁场分析

本文提出了一种直流永磁球型电机整体结构的设计理念.为了减小球型电机运动环节产生的摩擦力,针对球型电机结构特点,设计了基于十字轴结构的运动装置,并结合编码器以及倾角传感器提出了在球型电机内部可实现三位置检测的设计思路.为了得到球型电机的力矩输出与线圈激励的关系,对球型电机进行了磁场分析,利用麦克斯韦定律建立标量磁位的拉普拉斯方程,求解方程并利用边界条件得到空间磁场分布表达式,其结果可为进一步的研究和实验方案设计提供借鉴和参考.     

Influence of an aperture on the performance of a two-degree-of-freedom iron-cored spherical permanent-magnet actuator

This paper describes a computational and experimental study of a two-degree-of-freedom spherical permanent-magnet actuator equipped with an iron stator. In particular, it considers the effect of introducing an aperture in the stator core to facilitate access to the armature. The resultant magnetic field distribution in the region occupied by the stator windings, the net unbalanced radial force, and the resulting reluctance torque are determined by three-dimensional magnetostatic finite-element analysis. The predicted reluctance torque is validated experimentally, and its implications on actuator performance are described.     

Single disperser design for coded aperture snapshot spectral imaging

We present a single disperser spectral imager that exploits recent theoretical work in the area of compressed sensing to achieve snapshot spectral imaging. An experimental prototype is used to capture the spatiospectral information of a scene that consists of two balls illuminated by different light sources. An iterative algorithm is used to reconstruct the data cube. The average spectral resolution is 3.6 nm per spectral channel. The accuracy of the instrument is demonstrated by comparison of the spectra acquired with the proposed system with the spectra acquired by a nonimaging reference spectrometer.     

Theories for the design of a hybrid refractive-diffractive superresolution lens with high numerical aperture

By geometrical optics and the Rayleigh-Sommerfeld diffraction formula, theories for the design of a hybrid refractive-diffractive superresolution lens (HRDSL) with high numerical aperture are constructed. Differences between the profile of the diffractive superresolution element (DSE) with high numerical aperture and that with low numerical aperture are indicated. Optimization theory can obtain a globally optimal solution through a linear programming much more simplified than the corresponding one in Liu et al. [J. Opt. Soc. Am. A 19, 2185 (2002)]. The rules of the structure of the designed DSE are both theoretically proved and numerically verified. Comparison of this optimization theory with the other design theories and examples of designing the HRDSL with high numerical aperture are provided. Last, some limits of optical superresolution with high numerical aperture are set and compared with those for low numerical aperture.     

Optimum design of a grazing-incidence flat-field spectrograph with a spherical varied-line-space grating

A grazing-incidence spectrograph is designed by use of the flat-field image-focusing property of a spherical varied-line-space grating. Optimum grating parameters for mechanical ruling are selected by application of genetic algorithms. Two gratings, one for 2-5-nm and the other for 5-20-nm spectral regions, are designed, and their fabrication tolerances are analyzed.     

球面渐开线齿形的螺旋锥齿轮NURBS设计

 为避免传统设计和加工的近似球面渐开线齿形螺旋锥齿轮存在的缺陷,提出了一种新型螺旋锥齿轮设计方案．从齿面精确组成和形状特征出发,将球面渐开线理论应用于齿面基本曲线的方程表达式求导中,实现了齿面曲线的分段参数化．然后,对组成齿面的各区域分别求取齿面离散点数据,并采用三次均匀B样条曲面方法进行初步的拟合与拼接．为了进一步提高齿面精度,借助NURBS方法对拼接后的齿面进行了统一的NURBS精确拟合,并给出了齿面统一参数化的优化方法．最后的算例表明了相关方法的精确性和可行性,为螺旋锥齿轮的数字化设计与NURBS加工提供了新的思路与途径．     

Prism design based on changes in image orientation

We present a method of designing a prism to produce an image with a specific orientation. Traditional prism design of this kind is done by trial and error with the aid of geometrical drawing and cannot provide analytical results. Using skew ray tracing sensitivity analysis, we present a merit function that can specify changes in image orientation after the image is reflected by an arbitrary number of flat boundary surfaces. Two design approaches are proposed. One can produce a prism with a minimum number of flat boundary surfaces with the aid of an auxiliary unit vector. The other can produce many configurations of prisms but without the above feature. An illustrative example is used to demonstrate the validity of the proposed approaches. Eight new configurations, which can produce the same change in image orientation, are obtained from the proposed design approaches.     

General topology optimization method with continuous and discrete orientation design using isoparametric projection

A general topology optimization method, which is capable of simultaneous design of density and orientation of anisotropic material, is proposed by introducing orientation design variables in addition to the density design variable. In this work, the Cartesian components of the orientation vector are utilized as the orientation design variables. The proposed method supports continuous orientation design, which is out of the scope of discrete material optimization approaches, as well as design using discrete angle sets. The advantage of this approach is that vector element representation is less likely to fail into local optima because it depends less on designs of former steps, especially compared with using the angle as a design variable (Continuous Fiber Angle Optimization) by providing a flexible path from one angle to another with relaxation of orientation design space. An additional advantage is that it is compatible with various projection or filtering methods such as sensitivity filters and density filters because it is free from unphysical bound or discontinuity such as the one at θ = 2π and θ = 0 seen with direct angle representation. One complication of Cartesian component representation is the point‐wise quadratic bound of the design variables; that is, each pair of element values has to reside in a given circular bound. To overcome this issue, we propose an isoparametric projection method, which transforms box bounds into circular bounds by a coordinate transformation with isoparametric shape functions without having the singular point that is seen at the origin with polar coordinate representation. A new topology optimization method is built by taking advantage of the aforementioned features and modern topology optimization techniques. Several numerical examples are provided to demonstrate its capability. Copyright © 2014 John Wiley & Sons, Ltd.     

Studying grain boundary regions in polycrystalline materials using spherical nano-indentation and orientation imaging microscopy

In this article, we report on the application of our spherical nanoindentation data analysis protocols to study the mechanical response of grain boundary regions in as-cast and 30% deformed polycrystalline Fe–3%Si steel. In particular, we demonstrate that it is possible to investigate the role of grain boundaries in the mechanical deformation of polycrystalline samples by systematically studying the changes in the indentation stress–strain curves as a function of the distance from the grain boundary. Such datasets, when combined with the local crystal lattice orientation information obtained using orientation imaging microscopy, open new avenues for characterizing the mechanical behavior of grain boundaries based on their misorientation angle, dislocation density content near the boundary, and their propensity for dislocation source/sink behavior.     

The effect of cristallographic orientation on damage in MgO due to spherical particle impact

A single stage gas gun has been used to fire spherical chrome steel and WC particles at variously oriented and prepared MgO single crystals at velocities of up to 350 m sec^–1. The resultant damage has been studied by optical and scanning electron microscopy, dislocation etching and surface profilometry, and mass losses have been determined gravimetrically. The measured crater dimensions and the mass loss data have been compared with the predictions of a simple analytical model of the impact event.     

Stator design of a new type of spherical piezoelectric motor

The stator design of a new type of spherical motor driven by piezoelectric actuators is developed. A curved piezoelectric actuator is designed to attach to the spherical surface. A series of the curved piezoelectric actuators is laid in a line around a spherical surface. By applying an appropriate voltage signal with phase difference on neighboring actuators, a traveling wave is generated on the hemispherical shell. Each set of curved piezoelectric actuators is designed to provide motion with a single degree-of-freedom (DOF). With two or three sets of the piezoelectric actuators constructed to be mutually perpendicular, the motor can provide 2-DOF or 3-DOF motion. Stator design and analysis and experiment for the 1-, 2-, and 3-DOF conditions are presented in this article. Analytical calculation and experiment results of several fundamental characteristics of the stator are in good agreement. Performance evaluation of rotation speed and torque of the stator and some implementation problems are also addressed.     

Effect of a spherical explosion upon the flight path and spatial orientation of a projectile

A possible defense of an armored vehicle against a high-kinetic-energy projectile is based on generating a strong explosion in a close proximity of the projectile and at some distance from the vehicle. In this exposition we suggest a simplified analytical model that bounds the effect of an explosion upon the flight path and spatial orientation of the projectile.     

PET灌装新标准源于客户需求

Schindel家族自1911年起创立了Rhon Sprudel集团。1989年，Egon Schindel先生作为家族第三代继承人接管了公司业务。从那时起，公司取得了长足的进步，但是公司成长的目的并不仅仅表现为规模的增长。