基于PLC的气密性检测仪校准装置的研究

气密性检测设备已普遍应用于汽车、家电等制造行业。通过气密性检测已经成为确保零部件密封性的重要测试手段。然而,由于我国气密性检测技术发展时间较短,目前还没有对相关设备建立气密性方面的校准规范,对于泄漏量的检测也没有可溯源的国家标准。本文以差压式气密性检测仪为研究对象,通过对校准现状的分析,进行基于PLC的气密性校准装置研究,确保气密性检测仪测量量值的准确可靠。     

悬挂式负压型泄漏检测装置

本文介绍了一种很有特点的气密性在线检测装置。通过采用差压型泄漏检测仪和选择负压测试法，再从被测对象特征和生产线工艺布置的实际情况出发，研制了一套紧凑，高效的悬挂式执行装置，很好地解决了压入缸体的闷盖和母体结合的气密性的在线检测总是。     

乙炔减压器检测的探讨

乙炔减压器主要应用于焊接、切割及工艺过程中作为溶解乙炔气的减压装置 ,有降压和稳压两种作用。目前 ,有的计量部门及工矿企业计量室只是对乙炔表进行检定 ,而乙炔减压器的灵活性及气密性没有进行检测调试。因为乙炔气是一种可燃性气体 ,如果乙炔减压器阀门的灵活性及气密性出现问题 ,造成乙炔气泄漏 ,将直接影响到人生安全及安全生产。因此 ,对乙炔减压器的检测是有必要的。如果直接把乙炔减压器安装乙炔气瓶上检测其阀门的灵活性及气密性 ,将是最简单、最直接的方法。但是此方法在检定室内进行是很危险的。笔者在实际检测工作中总结了一…     

谈谈气调库的气密性

本文论述了气调库气密性的确定方法，气密材料的选择及气密层的做法，介绍了用正压法检测气调库气密性的具体操作过程，并给出了国内外的不同气密性标准。     

高氢工业炉气密性检测的新模型

对高氢工业炉气密性检测的现状进行了简介,并重点介绍了一种自动检测工业炉气密性的数学模型;最后提出了气密性检测技术未来的发展方向,可将红外线热成像技术应用于泄漏位置的定点检测。     

手持式电子设备气密性检测方法

该文针对手持式电子设备防水的要求,介绍了气密性检测技术原理,对当前各种气密性检测方法进行比较,提出更优的气密性检测方法,并通过试验进行分析研究,对提高手持式电子设备密封检测的生产效率具有非常现实的借鉴意义。     

外压直压法摄像机气密性检测系统的设计

针对传统的直压和差压气密性检测方法难以实现对全密封器件的泄漏检测,提出了一种外压直压法摄像机气密性检测方案.在介绍外压直压法检测原理及相关气密性公式的基础上,设计了一种针对摄像机密封性能的检测系统,并搭建了实验样机.摄像机气密性实验测试结果表明,该系统可以快速、准确且稳定地检测出摄像机的大漏、小漏及合格等指标;系统检测周期少于40s,为全密封器件的气密性检测提供了解决思路.     

Elman网络温度预测气密性检测研究

分析温度在差压法气密性检测中对检测准确度的影响及影响温度变化的因素,提出建立Elman网络,利用气密性检测平台在不同实验参数条件下得到的试验样本来训练网络。将训练好的神经网络用来预测气密性检测中待测密闭容器内的温度,并将预测得到的温度应用到气密性检测判断中。通过与应用较为广泛的BP网络和实际泄漏流量值比较可得,Elman网络进行41次训练后就达到预设目标,而且预测准确度更高。经过温度补偿后的泄漏流量值为12.67 m L/min(实际值为13 m L/min),相对误差为2.52%,极大地提高气密性检测的准确度。     

减压器校准装置的研制

减压器主要是用来控制气体输出压力,其准确性直接影响飞机各部件的气密性试验结果。由于无减压器的校准装置,因此该类减压器的校准过程:只能把两块压力表分别拆卸,进行各自校准,而对调节阀及整个减压器的气密性却没有校验。所以研制一台减压器校准装置是非常必要的。     

气密性测试技术在生产中的应用

正一、常用的气密性测试方法干式泄漏检测法有多种,在生产中采用最多的主要是直接压力测量法(又称绝对压力测量法)和差压测量法两种,它们的共同点是均以压缩气替代真实的工作介质,也就是以气密性试验模拟液密性试验。按这两种工作原理开发的泄漏检测装置有些已成为系列化的、成熟的产品,大量配置在现代化的生产线上。1.直接压力测量法直接压力法测量系统如图1所示,由气源、过滤器、平衡阀、压力传感器等部分组成。     

Structural and optical properties of AlxOy/Pt/AlxOy multilayer absorber

We report on the microstructure and optical properties of Al_xO_y–Pt–Al_xO_y interference-type multilayer films, deposited by electron beam (e-beam) deposition onto corning 1737 glass, silicon (1 1 1) and copper substrates. The structural properties were investigated by Rutherford backscattering spectrometry, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The optical properties were extracted from specular reflection/transmission, diffuse reflectance and emissometer measurements. The stratification of the coatings consists of a semi-transparent middle Pt layer sandwiched between two layers of Al_xO_y. The top and bottom Al_xO_y layers were non-stoichiometric with no crystalline phases present. The Pt layer is in the fcc crystalline phase with a broad size distribution and spheroidal shape in and between the rims of Al_xO_y. The surface roughness of the stack was found to be comparable to the inter-particle distance. The optical calculations confirm a high solar absorptance of ∼0.94 and a low thermal emittance of ∼0.06 for the multilayer stack, which is attributed not only to the optimized nature of the multilayer interference stacks, but also to the specific surface morphology and texture of the coatings. These optical characteristics validate the spectral selectivity of the Al_xO_y–Pt–Al_xO_y interference-type multilayer stack for use in high temperature solar-thermal applications.     

Bulk crystalline BaPb34Bi14O3: A ceramic superconductor

The preparation conditions of the high T_C ceramic superconductor Ba(Pb,Bi)O₃ is correlated with the superconducting transition. Transition onsets of all materials are similar, but transition widths and transition completeness is strongly dependent on firing temperature. Only materials prepared over a narrow temperature range, resulting in a nearly ideal weight loss, have a complete and narrow transition.     

Electrostriction in Pb (Zn13Nb23)O3

The electrostriction in $\text{Pb (Zn}{}_{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}\text{Nb}{}_{\mathrm{<mtext>2</mtext><mtext>3</mtext>}}\text{)}\text{O}{}_3$ crystals has been investigated using a strain gauge method. In the ferroelectric phase below 140 C, the strain vs the electric field shows a hysteresis, which is ascribed to the effect of ferroelectric domains. A quadratic relation holds between the strain x and the electric polarization P as x = QP² above about 170 C in the paraelectric phase. Values of the electrostrictive Q coefficients are determined from the measurements near 190 C, as Q₁₁ = 1.6·10^?2m⁴/C², Q₁₂ = ?0.86·10^?2m⁴/C², and Q₄₄ = 0.85·10^?2m⁴/C².     

Synthesis of a new perovskite Pb(Li14Nb34)O3

A high-pressure technique was adopted to obtain perovskite-type $\text{Pb(Li}{}_{\mathrm{<mtext>1</mtext><mtext>4</mtext>}}\text{Nb}{}_{\mathrm{<mtext>3</mtext><mtext>4</mtext>}}\text{)}\text{O}{}_3$. A new perovskite $\text{Pb(Li}{}_{\mathrm{<mtext>1</mtext><mtext>4</mtext>}}\text{Nb}{}_{\mathrm{<mtext>3</mtext><mtext>4</mtext>}}\text{)}\text{O}{}_3$ was characterized to have a cubic symmetry with $\text{a}{}_{\mathrm{<mtext>o</mtext>}}\text{= 4.069}\text{A}\text{?}$; Li and Nb ions in the B-site of perovskite lattice may be in a random arrangement.     

Magnetic,electrical and thermal studies on the V1−xMox02

The monoclinic-to-tetragonal structure transition of oxides V_1?xMo_x0₂ with $\text{0≤}\text{x}\text{≤0.20}$ has been studied by means of DTA, X-ray diffraction, magnetic susceptibility (powder samples) and electrical conductivity (single crystals) measurements within the temperature region 80 K to 400 K. A linear decrease of the transition temperature of 11 K per atom % Mo was observed. The magnetic susceptibility of the low temperature phase was found to be temperature independent paramagnetic for all preparations. Electrical conductivity measurements on the same phase showed crystals with $\text{x}\text{? 0.04}$ to be semiconducting, while a metallic behavior was observed in the region $\text{0.10 ?}\text{x}\text{? 0.14}$.     

n-PbTep+−Pb1−xSnxTe heterojunctions prepared by a modified hot wall technique

$\text{n-PbTe}\text{p}{}^{\mathrm{+}}\text{?}\text{Pb}{}_{\mathrm{1?x}}\text{Sn}{}_{\mathrm{x}}\text{Te}$ heterojunctions with a long wavelength spectral cutoff (λ_c ≈ 6 μm) were prepared using the double-channel hot wall technique. The electrical and photoelectrical properties of the heterojunctions at 77, 197 and 300 K were investigated. Detectors with R_oA equal to 170 Ω cm² and a quantum efficiency of 25–40% were obtained. Reasons for the shift of the long wavelength spectral cutoff of the heterojunctions towards shorter wavelengths are given.     

Optimization of AlxOy/Pt/AlxOy multilayer spectrally selective coatings for solar-thermal applications

Spectrally selective Al_xO_y/Pt/Al_xO_y multilayer absorber coatings were deposited onto corning 1737 glass, Si (111) and copper substrates using electron beam (e-beam) vacuum evaporator at room temperature. The employment of ellipsometric measurements and optical simulation was proposed as an effective method to optimize and deposit multilayer solar absorber coatings. The optical constants (n and k) measured using spectroscopic ellipsometry, showed that both Al_xO_y layers, which used in the coatings, were dielectric in nature and the Pt layer was semi-transparent. The optimized multilayer coatings exhibited high solar absorptance α ∼ 0.94 ± 0.01 and low thermal emittance ? ∼ 0.06 ± 0.01 at 82 °C. The Rutherford backscattering spectroscopy (RBS) data of Al_xO_y/Pt/Al_xO_y multilayer absorber indicated the Al_xO_y layers present in the coating were nearly stoichiometry. The scanning electron microscope analysis (SEM) result indicated that the average diameter and inter-particles distance of Pt grains were statistically about 146 ± 0.17 nm and 6-10 ± 0.2 nm respectively.     

Reactive plasma deposited SixCyHz films

Si_xC_yH_z films have been prepared at 200°C by reactive plasma deposition from SiH₄ and CH₄ diluted in helium in a tubular reactor. These films have a ratio s (equal to $\text{Si}\text{(}\text{Si+C}\text{))}$ ranging from 0.2 to 0.8, a refractive index ranging from 1.96 to 2.6 and an optical energy band gap in the range 2.7-2.2 eV. The total quantity of hydrogen in the film is 40% when s=0.5. Infrared analysis shows that these films have large fractions of homonuclear bonds and that this material is best described as a polymer. Mass spectrometric measurements of the gaseous products formed in the SiH₄-CH₄-He plasma have been performed and the results are related to the composition of the deposited layers.     

Core-current-enhanced domain-wall pinning in nanocrystalline Fe/sub 73.5/Cu/sub 1/Nb/sub 3/Si/sub 15.5/B/sub 7/ ribbon

We have studied the influence of surface fields H/sub p/ (generated by either direct or alternating core current) on soft magnetic properties of amorphous and nanocrystalline Fe/sub 73.5/Cu/sub 1/Nb/sub 3/Si/sub 15.5/B/sub 7/ ribbon. While in an amorphous ribbon the coercive field H/sub c/ decreases with H/sub p/, in the same optimally annealed ribbon (H/sub c/=1.3 A/m, M/sub m//spl ap/M/sub s/) H/sub c/ increases with H/sub p/ for all the explored types of H/sub p/ (static and dynamic with different phases with respect to that of the magnetizing field H). The unexpected increase of H/sub c/ in nanocrystalline ribbon is associated with the influence of H/sub p/ on the surface and main (inner) domain structure. Here, we develop a model that takes into account this influence and explains the experimental results.