浅述三星TOC技术

介绍了三星TOC（Transparent＆Opaque Color）技术双色注塑技术使用性及耐久性好、成本低、提高产品精密度等特点,并介绍了双色注塑所应用的旋转式、模腔旋转式、滑动式、水平旋转模块式、垂直旋转模块式、水平旋转模腔式、移动式、多层夹心式等8大类别模具。对双色注塑成型利用模具或设备结构,使两种原料先后射出并紧密结合成型的原理也做了介绍。     

旋转式压弯金属板装置

采用旋转压模压弯金属薄板,可以不使用支承衬垫,节省动力。旋转压模包括三个部分:带有V型槽口的摆动轴、滑动座架和固定机座。开始加压弯曲时,V型槽口的两个突角接触工件。继续压弯时,摆动杆在座架内旋转,一个突角压住工件,另一个突角迫使金属薄板的外伸部分沿着固定机座弯曲。摆功杆的运动行程要比预想得到的弯曲角度稍大—些,以补偿金     

某飞机前起落架旋转臂分模面处疲劳强度可靠性计算

本文应用正态分布函数代数运算法则推导了复合应力和疲劳强度正态分布的计算公式;在此基础上,根据应力—强度数学模型,按串联系统,对前起落架旋转臂分模面处的疲劳强度可靠性进行了计算。     

波纹管管坯加工可调旋转拉伸凹模

本文提出了波纹管管坯加工的两种新型旋转拉伸凹模,解决了过去凹模设计中钢珠误差的影响问题。同时,一只凹模可以拉伸出多种壁厚的管坯,为波纹管的新产品试验提供了方便,并大大提高了模具的使用寿命。     

旋转凹模的折弯模具

旋转凹模是由V型槽圆柱形凹模、鞍形支架和凸模组成的。该模具可以对板料进行折弯。在折弯时,旋转凹模的两个顶端先压住金属板,当冲床滑块继续下降时,一个顶端压住板材,凹模在鞍形支架里旋转,使另一顶端对板材进行折弯。为了补偿板料的弹性回跳,凹模的V型槽可以制成小于90°。     

基于DEFORM的大型封头整体锻造工艺数值模拟

大型整体封头越来越受到重视,需要开发可行的制造工艺。通过采用数值模拟的手段,设计了采用上模和下模的整体封头锻造工艺,对两种上模旋转下压的方式进行了对比,通过DEFORM-3D塑性成形软件对锻造过程进行了模拟计算,分析了终锻后锻件的等效应变分布。结果表明,通过采用上模旋转下压的方式,可以得到所需的封头,锻件尺寸符合要求。     

数控转塔冲床C轴传动机构改进

介绍了数控转塔冲床现有的旋转模驱动机构的不足之处,提出一种改进型的带轮传动机构,经过验证,旋转模的加工精度得到提高,特别适用于Y轴长行程的数控转塔冲床。     

球面零件冷挤压脱模机构研究与模芯失效分析

内球面零件精密冷挤成形后,由于球面回弹对模芯产生很大正压力,导致轴向顶出脱模阻力大,顶出时可能会使内球面零件端口发生严重变形,因此考虑采用旋转顶出方式来消除模芯和滑履球面摩擦力进行脱模,文中对旋转顶出的脱模方法原理进行分析,并计算重要参数螺旋升角,设计出合理旋转顶出脱模机构,最后通过工艺实验来证明旋转顶出的脱模方式具有...     

金属板材旋转弯曲法

旋转弯曲法的弯曲力要比其他方法小得多,而且模具简单,不需要特殊设备。这种弯曲法是在上模装一个圆柱形旋转器,旋转器经淬硬,两爪磨光。在弯曲板料时,旋转器的一个爪把板料压紧在下模3上,     

旋转凹模冷镦机弧面凸轮分度机构设计与仿真

建立了旋转凹模冷镦机弧面凸轮分度机构的数学模型,并结合实际应用情况设计了弧面凸轮分度机构参数,选取了弧面凸轮轮廓曲面运动规律。最后通过具体实例,使用Pro/E、Matlab对弧面凸轮工作轮廓面进行参数化建模,使用ADAMS建立弧面凸轮分度机构动力学模型,并对其运动性能进行了模拟仿真。研究表明,弧面凸轮分度机构作为旋转凹模冷镦机传动件在高速工况下运动平稳、停歇期定位精度达到36″。     

大惯量风机采用电机驱动的启动分析

阐述了风机正常运转和启动对电机的要求,分析了大转动惯量的风机直接启动所存在困难,针对某改造项目中的电机启动问题进行多个启动方案的对比选择,得出了最终解决办法,给风机设计者及用户提供了可借鉴的实例.     

LD注入调频扫描系统研究

为了减小扫描系统测量误差,可以利用半导体激光器注入式调频装置和光栅来建立扫描系统。通过改变注入电流来改变半导体激光器的输出光频,使输出光入射在光栅上,随着频率的改变,衍射光的衍射角会发生改变,进而衍射光点的位置发生改变,从而实现无机械光点扫描,能够消除扫描测量过程中机械抖动和振动带来的误差。     

Zero-loss energy filtering under low-dose conditions using a post-column energy filter

Electron cryomicroscopy combined with energy filtering can be performed under low-dose conditions using a post-column energy filter. The microscope combined with the filter is set up such that it can be used with similar ease as a conventional microscope, the main difference being that all filter and microscope control is performed through a central computer and images are recorded with a cooled slow-scan CCD camera. The microscope can also still be used for regular imaging on film as without the filter. Owing to the 18 times post-magnification of the filter, the microscope normally has to be operated at a small magnification, e.g. 3000×, and the beam has to be contracted to a small spot, e.g. 5 mm, in the plane of the microscope viewing screen. Computer control allows one to perform a variety of tasks automatically, such as autofocusing, thickness measurements, most-probable-loss imaging, CCD spot-scanning and tomography. The gain in contrast due to zero-loss energy filtering is analysed using visual inspection, power spectra and Fourier ring correlation. The thickness range for ice-embedded specimens in which a filter at 120 kV is most useful appears to be between 100 and 300 nm.     

基于MEMS技术的胃肠道无线内窥镜的研究

胃肠道无线内窥镜主要用于胃肠道疾病的诊断。其核心部分为一可吞服的胃肠道摄像无线发射的药丸,可将摄取到的胃肠道图像通过调制以无线方式发送出体外,然后经过信号解调,还原出视频信号,由计算机进行图像采集和处理。研究的关键在于摄像药丸的微型化和无线传输图像的稳定性。利用MEMS技术可以大大缩小摄像电路和发射电路的尺寸,从而大大缩小摄像药丸的体积。     

可拆分组合式设备描述库的研究

在详细分析了设备描述技术以及各类设备描述文件的基础上，提出了建立可拆分组合式设备描述库从而进一步得到现场设备的设备描述文件的方法。研究中引入了库函数的思想，以设备描述对象（DD Object）为切入点，将其进行分块归库，通过单独对库进行设备描述并对库进行叠加来实现设备描述文件。该方法成功实现了对现有设备描述的继承，同时简化了设备描述的实现，为减少设备描述语言升级后的再开发成本提供了一条有效的解决途径。这种分块（block）方法的可行性已经通过NI和FF-HSE等组态软件的读写得到了验证。     

A computer program to illustrate macro topography on electron backscattering

This paper describes a computer program which enables the trajectories of an electron to be followed inside a solid sample and its pathway if it is successful to exit the sample's surface, and to be considered a backscattered electron (BSE). The simulation aids to understand the backscattering process and the effect of the sample that has other than an ideal flat surface topography. Several types of surface for the sample are simulated: a flat surface which can be tilted, a rough surface represented by a sine wave, and a circular surface to represent filamentous structures. The target material is entered as its empirical formula so that its mean atomic number may be calculated. It is covered with a layer of conductive coating, and it may be structured with vertical or horizontal layers of a second-phase material. Where appropriate, the position of the electron beam impacting on the target may be moved in relation to the underlying structures. The passage of the electron through the substrate is displayed on the computer monitor in high-resolution graphics. Information about those electrons which return to the sample surface and are backscattered is stored for later analysis. The paths of these BSEs are replotted to show the volume of the sample from which the image-forming data are derived. Further graphic output provides histograms of the energy distribution and of the BSEs exit direction.     

Method for assessing the similarity and distance between curves/trials and its applications in gait analysis

In clinical assessment or sports exercise.it is common that a subject is required to repeat a specific per-formance so that a stable movement pattern is obtained and analysed.In practice,however,the trials done by a sub-ject vary more or less,depending on the psychological or physical conditions.Some of the trials can be used as rep-resentatives of the stable movement pattern,and some not.Therefore,there is a demand for a new method to identify which trials/curves are similar.The traditional methods used to assess curve similarity are not perfecfly suitable for the case where there are only a few of trials available.This study proposes a similarity-distance coefficient to assess the similarity of curves/trials.A group of designed curves are used to validate the coefficient.The results show that given joint kinematic data during gait as examples,tlle proposed coefficient call be used to quantitatively evaluate the similarity of trials,and thus find which trials would be representative(S)for the gait investigated.The proposed method could be applied in various situations where repeat movements have to be measured and analysed.     

A three-lead, programmable, and microcontroller-based electrocardiogram generator with frequency domain characteristics of heart rate variability

The objective of this study is to design and develop a programmable electrocardiogram (ECG) generator with frequency domain characteristics of heart rate variability (HRV) which can be used to test the efficiency of ECG algorithms and to calibrate and maintain ECG equipment. We simplified and modified the three coupled ordinary differential equations in McSharry's model to a single differential equation to obtain the ECG signal. This system not only allows the signal amplitude, heart rate, QRS-complex slopes, and P- and T-wave position parameters to be adjusted, but can also be used to adjust the very low frequency, low frequency, and high frequency components of HRV frequency domain characteristics. The system can be tuned to function with HRV or not. When the HRV function is on, the average heart rate can be set to a value ranging from 20 to 122 beats per minute (BPM) with an adjustable variation of 1 BPM. When the HRV function is off, the heart rate can be set to a value ranging from 20 to 139 BPM with an adjustable variation of 1 BPM. The amplitude of the ECG signal can be set from 0.0 to 330 mV at a resolution of 0.005 mV. These parameters can be adjusted either via input through a keyboard or through a graphical user interface (GUI) control panel that was developed using LABVIEW. The GUI control panel depicts a preview of the ECG signal such that the user can adjust the parameters to establish a desired ECG morphology. A complete set of parameters can be stored in the flash memory of the system via a USB 2.0 interface. Our system can generate three different types of synthetic ECG signals for testing the efficiency of an ECG algorithm or calibrating and maintaining ECG equipment.     

Microstructure and fracture behaviour of particle-reinforced metal–matrix composites

The fracture behaviour of particle-reinforced metal-matrix composites is shown to be controlled by a period of damage nucleation and evolution prior to final failure. The nucleation of damage can be by reinforcement fracture or decohesion and the mode of damage is shown to be controlled by the size of the reinforcement and segregation of alloying elements from the matrix. The nucleation and growth of damage can be monitored by a number of techniques. Acoustic emission and tomography are used here and the results are found to be consistent with simple models of void growth.     

Low energy beam transport for facility for rare isotope beams driver linear particle accelerator

The driver linac for the facility for rare isotope beams (FRIB) will provide a wide range of primary ion beams for nuclear physics research. The linac will be capable of accelerating a uranium beam to an energy of up to 200 Mev∕u and delivering it to a fragmentation target with a maximum power of 400 kW. Stable ion beams will be produced by a high performance electron cyclotron resonance ion source operating at 28 GHz. The ion source will be located on a high voltage platform to reach an initial beam energy of 12 keV∕u. After extraction, the ion beam will be transported vertically down to the linac tunnel in a low energy beam transport (LEBT) system and injected into a radio frequency quadrupole (RFQ) operating at a frequency of 80.5 MHz. To meet the beam power requirements, simultaneous acceleration of two-charge states will be used for heavier ions (≥Xe). This paper presents the layout of the FRIB LEBT and the beam dynamics in the LEBT. In particular, simulation and design of the beam line section before charge state selection will be detailed. The need to use an achromatic design for the charge state selection system and the advantage of an ion beam collimation system to limit the emittance of the beam injected into the RFQ will be discussed in this paper.