Water hammer with fluid–structure interaction in thick-walled pipes

A one-dimensional mathematical model is presented which describes the acoustic behaviour of thick-walled liquid-filled pipes. The model is based on conventional water-hammer and beam theories. Fluid–structure interaction (FSI) is taken into account. The equations governing straight pipes are derived by the cross-sectional integration of axisymmetric two-dimensional basic equations. The resulting FSI four-equation model has small correction terms and factors accounting for the wall thickness. Exact solutions of this model show that these corrections are important only for very thick pipes, with, say, a radius/thickness ratio smaller than 2.     

大型厚壁半球形封头热冲压成形的数值模拟

该文利用SuperForm软件，对带直边大型厚壁半球形封头的热冲压成形过程进行了有限元数值模拟。分析了厚壁半球形封头热冲压成形过程的变形特点及坯料与模具间摩擦系数、下模形状、温度等因素对封头成形后壁厚变化的影响。     

Formation of capillaries and optical fibers with the use of a high-temperature furnace with azimuthally inhomogeneous temperature field

The effect of two technological parameters—the azimuthal inhomogeneity of the wall thickness of the preform tubes and the azimuthal inhomogeneity of the temperature field of a high-temperature (HT) furnace—on the cross section ellipticity of the capillaries is investigated experimentally. SL-97-1 electron tube glass bulbs are used as the preform tubes. It is established that, when one uses an HT furnace with azimuthally homogeneous temperature field, the inhomogeneity of the wall thickness of a capillary coincides with that of the tube perform, irrespective of whether or not the preform tube is collapsed during drawing. In contrast, the ellipticity of the capillary depends on collapsing the perform tube and increases as the collapse coefficient increases. The azimuthal inhomogeneity of the temperature field leads to appreciable ellipticity of the cross sections even in capillaries drawn from preform tubes with small wall thickness inhomogeneity.     

A new glucose sensor based on encapsulated glucose oxidase within organically modified sol–gel glass

A non-mediated glucose biosensor is reported based on encapsulated glucose oxidase (GOD) within the composite sol–gel glass, which is prepared using optimum concentrations of 3-aminopropyltriethoxy silane, 2-(3, 4-epoxycyclohexyl)-ethyltrimethoxy silane, GOD dissolved in double distilled water and HCl. A white, smooth film of sol–gel glass with controlled thickness is also prepared at the surface of a Pt disk electrode without GOD to study the electrochemistry of ferrocene monocarboxylic acid at the surface of the modified electrode. The electrochemistry of ferrocene monocarboxylic acid at composite sol–gel glass electrode with varying thickness is reported. The GOD-immobilized film over the Pt disk surface shows a yellow colour. The new sol–gel glass in the absence and the presence of GOD is characterized by scanning electron microscopy (SEM). The enzyme-immobilized film of different thickness is made using varying concentrations of soluble sol–gel components applied to the well of the Pt disk electrode. The enzyme is cross-lined with the 3-aminopropyltriethoxysilane, one of the composite component of sol–gel glass using glyoxal at 4°C for 4 h. The response of non-mediated enzyme sensor is studied based on cyclic voltammetry and amperometric measurements. A typical amperometric response of the enzyme sensor having varying thickness of the modified sol–gel glass film is reported. The variation of the response time as a function of the film thickness is reported. The stability of cross-linked GOD to sol–gel glass is found to be more than a month without loss of enzymatic activity when the enzyme sensor is stored at 4°C.     

The influence of the silicon dioxide barrier films on the laser ablation destruction of the glass composites with the films drown from the sols

The laser ablation destruction of the composites with nano dimensional oxide one- or two-layers films drown from the sols on a glass substrate has been studied. It has been shown that the laser ablation destruction threshold energy density depends on the number and chemical composition of the layers and the drawing velocity. The ablation threshold energy density of the two-layer composites finds out mainly a tendency to decrease at the 3.8 mm/s drawing velocity, but at the 5.8 mm/s one—to increase that can be explained by the films thickness decreasing and the low-melting components from the glass substrate diffusion due to the barrier films diminishing.     

Millimeter-scale actuator with fiber-optic roller bearings

A technique combining semiconductor processing and fiber-optic technology has been developed to micromachine a 1-cm² silicon die that rolls on two wheels above a flat substrate. Each wheel consists of a glass capillary surrounding a fixed solid glass fiber axle. A 100-silicon die is anisotropically etched to create two variable width v-grooves. Each v-groove has a wide center section and two narrow ends, which is schematically illustrated as -==-. The capillary is free to rotate about the axle in the wide v-groove section while the axle is anodically bonded into the narrow v-groove ends. The gap between the die and the substrate is determined by the narrow v-groove width, fiber diameter, and capillary wall thickness. Several rolling die have been fabricated with 210-120 μm gaps. The coefficient of static friction (μ_S) has been investigated on several substrates as a function of the load on the die. Values for μ_S are compared to an unetched die with a silicon nitride coating. With loads ranging from 0-10 grams, the wheels reduce μ_S by more than 50% on borosilicate glass     

一种管材内径、外径、壁厚在线检测系统

本义介绍了一种用于管材内径、外径、壁厚的在线检测系统，详细说明了其检测系统的结构组成，测量原理，硬件电路和软件设计。     

基于DSP技术的爬壁机器人吸附控制系统设计

壁面吸附是爬壁机器人的基本功能之一,其吸附程度直接影响爬壁机器人的稳定性和移动速度;为此,设计了基于DSP技术的爬壁机器人吸附控制系统;选择爬壁机器人传感器装置,加设DSP数字信号处理器,设计爬壁机器人吸附控制器;在硬件结构的支持下,根据爬壁机器人的组成结构和工作原理,构建相应的数学模型;在该模型下,利用DSP技术计算爬壁机器人吸附力;通过爬壁机器人在壁面环境下的受力分析结果,确定爬壁机器人安全吸附条件;以吸附控制器作为执行机构,实现爬壁机器人的吸附控制;选择负压爬壁机器人作为测试样机,通过系统测试表明,在瓷砖、木板、玻璃三种壁面环境下,与两个对比系统相比,应用此次设计系统得出爬壁机器人吸附力的控制误差降低了2.04 N,倾覆风险系数降低了0.29,具有较好的吸附控制效果。     

厚膜型La2NixCu1-xO4复合氧化物的氧敏性能研究

采用甘氨酸-硝酸盐法合成了La2NixCu1-xO4（x=0～0．5）复合氧化物,制成了厚膜型元件,研究了烧结温度、膜厚、介质粉含量等对材料氧敏性能的影响。测试结果表明：700℃烧结、膜厚为80μm、介质粉含量为5％的厚膜型La2NixCu1-xO4的氧敏性能最优,400℃时的灵敏度可以达到7．1。     

A low-temperature IC-compatible process for fabricatingsurface-micromachined metallic microchannels

In this paper, a low-temperature integrated-circuit (IC)-compatible process for fabricating metallic microchannels is described. Arrays of 1-100 metallic microchannels have been fabricated on silicon and glass substrates. The process can be extended to many planar substrate materials including polymers and ceramics. The microchannels are formed using microelectro-formed metals. The microchannels demonstrated in this paper use nickel as the structural material and gold as the surface coating on the inside walls of the microchannels. The inner dimensions of the individual microchannels fabricated to date range from 30 μm to 1.5 mm in width, 0.5 mm to several centimeters in length, and 5-100 μm in thickness. The wall thickness ranges from 5 to 50 μm. The microchannel fabrication technology enables the fabrication of surface microchannels with a relatively large cross-sectional area. The metallic microchannels can be fabricated to extend from the substrate edge. Interfacing schemes are given for attaching external pressure feeds     

民居节能建筑外墙保温层最优厚度仿真

为提高建筑外墙保温层厚度计算结果的精度,提出基于LCCA(Life Cycle Cost Analysis)的民居节能建筑外墙保温层最优厚度计算方法。根据采暖度日数、建筑物围护结构的传热阻等值计算建筑外墙热损失。利用保温层投资与采暖燃料投资相加所得值,获取单位面积建筑外墙保温层的生命周期范围内总投资。采用反应系数法与z传递函数法分析并计算围护结构非稳态逐时热流。结合外墙热损失、保温层使用寿命内费用和墙体逐时热流分析结果,计算民居节能建筑外墙保温层最优厚度。实验发现,保温层存在一个最优厚度,可以使建筑的总费用降到最低;相同保温材料,最优保温层的厚度会随着现值因子增大不断增大,随着采暖度日数增大逐渐增大,随着非保温层热阻值增大不断减小;保温材料不同,最优保温层厚度的差异体现在随着现值因子、采暖度日数增大逐渐增大,随着外墙的非保温层热阻值增大逐渐减小;保温层最优厚度计算结果与实际值拟合度高。     

构件组合的抽象精化验证

针对构件组合的状态爆炸问题,改进了反例引导的抽象精化框架,提出了组合式的抽象精化方法,使构件组合的模型检验转化为各成分构件的局部抽象精化,降低了分析的复杂度.提出了在构件组合情况下基于等价关系和存在商的构件抽象方法,用构件抽象的组合建立构件组合的抽象;提出了组合确认定理并给出证明,使反例确认分解为在各构件上对反例投影的确认;通过对单个构件的等价关系的精化实现构件组合的抽象模型的精化.在模型检验构件组合的过程中,不需要为构件组合建立全局的具体状态空间.     

炼油过程模拟中油品组成划分方法的进展

油品组成的划分,是建立炼油过程反应动力学模型的基础。本文从建立炼油过程模型对油品组成划分的要求入手,归纳和总结炼油过程模拟中常用的油品组成划分法及最新的划分技术,并结合分析和计算技术的发展水平,分析每种方法的优缺点及其适用范围。     

DR图像缺陷检测的彩色合成方法

数字式X射线(DR)图像难以用一幅灰度图像同时显现不同壁厚部件的缺陷。为此,提出用一幅合成彩色图像显现缺陷的方法。对DR系统扫描铸件得到的浮点型数据,采用分段灰度拉伸的方法转换为3幅灰度BMP图像,其中,不同灰度段的图像含有被测铸件不同壁厚部件的缺陷,再将这3幅灰度图像合成为一幅彩色BMP图像。对其应用彩色C-V(Chan-Vese)模型分割缺陷,实验结果证明,该彩色合成方法能较好地分割出被测铸件不同壁厚部件的缺陷。     

Effect of mold stiffness on surface flatness of mold-pressed glass

This paper presents the effect of mold stiffness on the surface flatness of mold-pressed glass for glass molding and imprint processes. Phosphate and borosilicate glasses were pressed at their viscoelastic temperature region using flat molds of several kinds and subsequently cooled to room temperature. Surface flatness of the mold-pressed glasses was examined using a stylus surface profilometer. The glass surface curvature was observed after spontaneous demolding by thermal shrinkage stress of the glass and the mold during cooling. The curvature decreased with increasing mold stiffness, as determined by the Young’s modulus and mold thickness. The curvature also decreased with decreasing cooling rate during cooling, which was discussed in terms of the glass fragility. It was demonstrated that the Young’s modulus, mold thickness, and cooling rate are key factors for the control of the molded glass surface flatness.     

光纤传输的玻璃厚度测量装置

介绍一种新式的用平板电容器检测玻璃厚度装置。采用光纤传输与微机控制,使信号得到快速精确的处理,保证玻璃厚度测量,减轻了工人体力劳动,提高了产品质量。     

Optical measurement of pore scale velocity field inside microporous media

An experimental technique to quantify velocity field at pore scale with in microporous media, formed by packing of microglass spheres of size 200?μm inside a glass micro-model, is presented. A microparticle image velocimetry (μ-PIV) system is used to study velocity fields at four different spatial regions in the microporous medium. A combined particle image velocimetry (PIV) and particle tracking velocimetry (PTV) scheme is used to quantify velocity within a typical pore size of 10–50?μm. The experiments are conducted at four different flow rates. Two different measurement planes are selected for obtaining the detailed pore scale velocity field—one close to the glass wall and the other inside the porous medium at a distance 100?μm below the glass wall. The image processing technique for dealing with noisy data and sparse vector field has been discussed in detail. Probability density functions of transverse and axial velocity components are compared with available results in literature. The pore scale velocity field obtained can provide insight to flow properties in microporous media and can be a powerful tool to validate existing numerical results for flow through porous media.     

精馏塔多通道对角矩阵解耦控制仿真

在化工生产中,许多单元操作的控制涉及至少2个被控变量,因此产生至少2个以上的控制回路。在该类具有多个控制回路的多变量控制系统中,同一被控对象上的多个控制回路,在实现其各自的控制目标时,将发生相互作用和相互影响。精馏塔是化工等行业中广泛使用的高耗能分离设备,为满足工艺要求和节能,需将塔顶和塔底产品流控制在设计值,即双成分控制。通常,利用回流量和加热量作操纵变量分别控制塔顶和塔底产品的组成。不过,回流量的变化也会影响塔底产品的组成,加热量的改变也会影响塔顶产品的组成。当采用温度作为反映产品组成的间接指标时,塔顶和塔底温度控制回路具有强烈的耦合作用,会导致系统不稳定。一个简单有效的方法就是解出耦合,因此,本文先介绍了一种基于对角矩阵的温度解耦控制方案,并在MATLAB/Simulink平台进行了控制仿真。结果显示:与两个独立PID回路控制相比,对角矩阵解耦控制不仅能达到更优的控制效果,还具有极强的对象特性鲁棒性。     

Bond-quality characterization of silicon-glass anodic bonding

A simple testing method is presented that allows the comparison of the bond quality for anodically bonded wafers. An array of parallel metal lines of predetermined thickness is formed on a glass wafer. The estimation of the bond quality can be performed by visual inspection after the bonding. This method enables comparison of the anodic-bonding process performance for different glasses, for intermediate layers and various bonding conditions. The optimization of silicon-glass anodic bonding with an intermediate phosphosilicate glass (PSG) layer is shown using this technique.     

一种新型光学测量系统在高温环境中的应用研究

提出了一种高温条件下的在线光电测量系统,可直接用于浮法玻璃锡槽内玻璃成型区的玻璃厚度测量。建立了一种自动补偿玻璃板上下表面倾斜的单像机双目视觉传感器模型,变双CCD摄像机结构为单CCD摄像机结构。通过加装一组对称光学反射镜,镜像出一对虚拟摄像机,可在同一个CCD像面上采集到存在视差的2幅图像,从而消除玻璃板上下表面倾斜角引起的系统误差;同时,完成传感器在高温恶劣环境中的二维定位,保证了仪器设计基准与测量基准的统一。分析了高温气体湍流条件下激光传输光线起伏效应和光线起伏对激光测量系统性能的影响,提出利用先验法补偿系统热致光学误差;通过实验和在线实际应用证明:该系统测量精度能够满足玻璃厚度在线测量的要求。