O形圈用于旋转密封

一般认为 O 形密封圈不能用作旋转密封元件,但这不是普遍规律。如果 O 形圈以压缩状态而不是张紧状态安装在轻载旋转部位使用,它也能可靠地密封。因为拉紧状态下的合成橡胶,由于 GOW——Joule 热效应而趋于收缩,所以 O 形密封圈常常被认为用于旋转密封时是不可靠的。这样一来,旋转轴多使用唇形密封,其实,成本较低的 O 形密封圈在这些场合也能应用。     

法兰盘密封新技术

用O型密封圈对法兰盘进行密封,在实践中是可行的,新申请专利的密封技术用的是密压法兰,其特点是带有专用的槽(图1)。O型密封圈新的密封方案中,使容纳O型密封圈的空间这样来选择,即有一半紧紧包住O型圈,而其深度小于O型圈的直径。     

减少迷宫密封泄漏量的分析、设计与试验

通过迷宫密封泄漏量的计算,阐述了影响泄漏量的因素。分别对三种特性因素:密封齿形、节流间隙和节流口数进行分析。结果表明,圆形齿产生的泄漏量较大,尽量避免使用;节流间隙与泄漏量呈线性关系,取较小值密封效果较好;节流口数越多,泄漏量越小,但是随着节流口数增多,节流效果增加越不明显,并且经济成本较高,设计时需合理选用节流口数。试验也验证了光电转台迷宫密封满足工程应用要求。     

地面侦察情报设备的防水密封设计

探讨了地面侦察情报设备防水密封机壳的设计特点,对于防水密封机壳的结构设计及其在新型侦察情报设备上的应用作了有益的尝试,可作为防水密封机壳结构设计时参考。     

三维调节杆件真空密封结构设计及漏率检测

本文重点介绍了在真空腔内需要进行三维杆件的密封结构设计以及对该结构进行真空密封性能测试。利用焊接波纹管作为密封可动调节介质,并使用O形橡胶圈作为与腔体和杆件的密封材料,在大气压至1.0×10-6Pa之间具有良好的密封效果,和调节性能。     

二氧化碳吸收塔给料泵机械密封的改造

介绍了二氧化碳吸收塔给料泵机械密封在运行期间动、静环经常磨损造成泄漏的情况和O型圈造成泄漏的情况,详细分析了机械密封动、静环磨损的原因,并且提出了解决方法,保障了化工系统的连续稳定运行。     

关于水泵机械密封的技术分析

在给水设备的运转中,水泵是其重要的动力枢纽,水泵的机械密封效果是保证供水安全性、有效性的关键。水泵机械密封具有密封效果良好、密封参数高、功率较低等优点,而得到了广泛的应用。水泵机械密封常见的问题主要有渗漏、失效等,必须对于各类问题进行系统的分析,并且采取有效的技术处理措施。本文从专业技术的角度出发,简要分析了水泵机械密封的相关问题。     

S 波段径向线陶瓷密封窗的分析与设计

为了实现对径向线输入与输出部分的真空密封,优化高功率阵列天线的拓扑结构,本文研究了一种径向线陶瓷 密封窗。基于模式匹配法理论分析了径向线陶瓷密封窗的传输与反射特性,之后以此为依据对其进行了仿真设计,改进 了结构实现方式,降低了三相点和突变结构对密封窗表面电场的影响。设计结果表明：该径向线陶瓷密封窗反射系数小 于0.1,设计功率容量约150 MW。     

激光传输通道动密封防尘结构设计

激光传输通道工作环境复杂,为满足系统密封要求,设计了一种磁流体动密封结构。主要由磁流体、极靴、永磁体、内筒、外筒和盖板组成。建立磁场仿真模型,计算了不同密封间隙内磁场的大小及其分布。分析了01～04mm间隙下的理论耐压能力,根据工程要求选取了密封间隙02mm。耐压值可以达到026 MPa。应用Block Lanczos法对内筒进行模态分析,一阶固有频率69094 Hz,远高于经纬仪固有频率,满足动力学要求。最后进行试验并分析了离心力对密封的影响。结果表明密封结构的各项指标均满足可以要求。     

高密度密封电子设备热设计与结构优化

通过对一种高密度密封电子设备的设计实践,阐述了密闭设备结构热设计中的设计思想及一些具体散热结构.同时应用Flotherm热分析软件进行结构热设计验证与优化,从而对多种分析结果比较,并找出了适合该设备的散热模型,以供实际应用借鉴.     

无铅电子封接玻璃材料性能的改进

为了提高电子器件封接玻璃材料的性能,采用固相烧结法制备了B2O3-ZnO-CaO无铅电子封接玻璃材料,并研究了其成分与性能的关系。结果表明:当w(B2O3)为45%,w(ZnO)为34%,w(CaO)为10%,w(Na2O)为2%,w(K2O)为3%,其他成分为质量分数6%时,可制得一种封接温度低于600℃,tk–100≥300℃,击穿场强≥23×106V/mm,线膨胀系数为≤7.0×10–6,抗折强度在117.65～146.57MPa的低熔点无铅电子封接玻璃材料。     

SOI集成光电子器件

Silicon-on-insula tor(SOI)集成光电子器件的工艺与标准CMOS工艺完全兼容,采用SOI技术可以实现低成本的整片集成光电子回路。文章回顾了近几年来SOI集成光电子器件的发展以及一些最新的研究进展。     

Moisture evolution analysis of sealing glasses used in integrated circuit packaging

Free moisture in the cavity of a sealed hermetic integrated circuit is considered an important reliability hazard. The contribution to the cavity moisture by the packaging materials can be studied effectively using the technique of moisture evolution analysis (MEA). The technique involves passing a dry carrier gas over the sample at high temperatures and measuring its moisture uptake coulometrically. The standard moisture evolution technique has been modified to quantify the kinetics of moisture evolution from sealing glasses used for hermetic sealing of I.C. packages which are primary contributors to total cavity moisture. It is also shown that once the moisture evolution mechanisms are understood, the technique of moisture evolution analysis can be correlated to a more complex, industry standard method for free cavity moisture measurement in a sealed hermetic package (RGA-mass spectrometry). MEA can therefore be used for the process control and prediction of free cavity moisture of hermetically sealed I.C. packages.     

Elimination or minimisation of optoelectronic crosstalk betweenphotodiodes and electronic devices in OEIC on Si

The optoelectronic crosstalk between photodiodes and electronic devices is observed and investigated in OEICs based on silicon. Results show that the phenomenon is closely related to the diffusion of minority carriers, generated by photon absorption. The crosstalk can be eliminated or minimised by either placing the electronic devices far from the photodiode, or by enclosing them with a reverse-biased guard ring diode     

Nanowires for UV–vis–IR Optoelectronic Synaptic Devices

Simulating biological synaptic functionalities through artificial synaptic devices opens up an innovative way to overcome the von Neumann bottleneck at the device level. Artificial optoelectronic synapses provide a non-contact method to operate the devices and overcome the shortcomings of electrical synaptic devices. With the advantages of high photoelectric conversion efficiency, adjustable light absorption coefficient, and broad spectral range, nanowires (NWs)-based optoelectronic synapses have attracted wide attention. Herein, to better promote the applications of nanowires-based optoelectronic synapses for future neuromorphic systems, the functionalities of optoelectronic synaptic devices and the current progress of NWs optoelectronic synaptic devices in UV–vis–IR spectral range are introduced. Furthermore, a bridge between NWs-based optoelectronic synaptic device and the neuromorphic system is established. Challenges for the forthcoming development of NWs optoelectronic synapses are also discussed. This review may offer a vision into the design and neuromorphic applications of NWs-based optoelectronic synaptic devices.     

密封橡胶圈毛刺缺陷检测方法的研究

针对密封橡胶圈毛刺缺陷,提出了一种新的检测方法,该方法根据圆轮廓点在不同象限的分布情况不同,首先使用窗口模板寻找可疑点,然后对可疑点进行二次检测,滤除非毛刺点。实验结果表明该方法比传统的毛刺检测方法处理速度更快,且检测结果可靠。     

一种基于位平面分解的图像加密方法

为了找出速度快、保密性好的加密方法,研究了一种采用光电器件和位平面分解相结合的图像加密方法,将图像分解为位平面,利用伪随机矩阵作密钥,通过偏振编码对位平面分别加密.取lena图片进行加密、解密仿真实验,分析了该加密方法的安全性.结果表明,经加密、解密恢复的图像与原始图像一致,加密后,原始图像的像素灰度信息被淹埋,信息熵接近最大,不确定性极高,攻击者不易分析原图像的平均灰度值,降低泄漏特征信息的可能.     

Selective bonding and encapsulation for wafer-level vacuum packaging of MEMS and related micro systems

A laser-assisted bonding technique is demonstrated for low temperature region selective processing. A continuous wave carbon dioxide (CO₂) laser (λ=10.6 μm) is used for solder (Pb37/Sn63) bonding of metallized silicon substrates (chips or wafers) for MEMS applications. Laser-assisted selective heating of silicon led to the reflow of an electroplated, or screen-printed, intermediate solder layer which produced silicon–solder–silicon joints. The bonding process was performed on fixtures in a vacuum chamber at an air pressure of 10⁻³ Torr to achieve fluxless soldering and vacuum encapsulation. The bonding temperature at the sealing ring was controlled to be close to the reflow temperature of the solder. Pull test results showed that the joint was sufficiently strong. Helium leak testing showed that the leak rate of the package met the requirements of MIL-STD-883E under optimized bonding conditions and bonded packages survived thermal shock testing. The testing, based on a design of experiments method, indicated that both laser incident power and scribe velocity significantly influenced bonding results. This novel method is especially suitable for encapsulation and vacuum packaging of chips or wafers containing MEMS and other micro devices with low temperature budgets, where managing stress distribution is important. Further, released and encapsulated devices on the sealed wafers can be diced without damaging the MEMS devices at wafer level.     

直角三棱镜补充视角的密封圈缺陷检测研究

为解决三维激光检测中被测物体底面点云无法被高效获取的问题,本文提出了基于直角三棱镜折射原理的补充视角三维点云扫描获取方法。该方法使用直角三棱镜将底面图像折射到侧面,弥补了三维检测的底面检测视角缺失的问题,补充了底面检测视角。本文以密封圈作为缺陷检测对象,采用结构光三维相机采集三维点云。与直接扫描法相比,本方法可以一次性实时、快速地寻找出密封圈完整的表面缺陷,尤其使底面缺陷检测变得更容易,且无需设置特殊的夹取装置或复杂的机械臂等机械结构,仅需增加一块直角三棱镜。实验证实,直角三棱镜补充视角的点云扫描方法能够达到成像要求,对常见的密封圈断裂缺陷与塌陷缺陷均可很好的检出,检测准确率可达到100,满足密封密封圈缺陷检测的需求。     

Carbon and Graphene Quantum Dots for Optoelectronic and Energy Devices: A Review

As new members of carbon material family, carbon and graphene quantum dots (CDs, GQDs) have attracted tremendous attentions for their potentials for biological, optoelectronic, and energy related applications. Among these applications, bio‐imaging has been intensively studied, but optoelectronic and energy devices are rapidly rising. In this Feature Article, recent exciting progresses on CD‐ and GQD‐based optoelectronic and energy devices, such as light emitting diodes (LEDs), solar cells (SCs), photodetctors (PDs), photocatalysis, batteries, and supercapacitors are highlighted. The recent understanding on their microstructure and optical properties are briefly introduced in the first part. Some important progresses on optoelectronic and energy devices are then addressed as the main part of this Feature Article. Finally, a brief outlook is given, pointing out that CDs and GQDs could play more important roles in communication‐ and energy‐functional devices in the near future.