汽油超声喷嘴的设计研究

为了进一步细化汽油雾化粒径,该文基于一维振动理论研究设计了一种汽油超声喷嘴。采用有限元法分析振动模态和谐响应,获得其谐振频率、振动位移与工作应力分布,理论频率30.157kHz与HP-4286A LCR精密阻抗测试仪实测频率30.862kHz接近。此外,对超声喷嘴的汽油雾化效果进行了理论计算分析与试验研究,理论计算粒径?24.38μm,实测粒径?27.62μm,两者基本一致,比传统汽油喷油嘴的雾化粒径(约?50μm)缩小约2倍。研究结果有效地改善了汽油的雾化质量,提高了燃油利用率。     

超声雾化频率与雾化粒径关系的实验研究

研究建立了超声雾化装置,使用不同频率的压电换能器对抑尘剂进行了雾化,利用welas 2000气溶胶粒径谱仪对雾化产生的雾滴粒径进行了测定。结果表明,相同雾化条件下,雾滴粒径随压电换能器的振动频率增大而减小,减小量与理论计算具有较好的相合性。     

基于有限元模型的超声切割刀优化设计

超声切割刀在材料加工领域中有广泛的应用前景,可用于切割各种复合材料等硬脆材料。该文利用ANSYS有限元分析软件建立超声切割刀的有限元模型,对其进行模态分析和谐响应分析。仿真结果显示,超声切割刀在40 kHz频率附近存在轴向纵振模态,其振动节点位于安装环和压电陶瓷中心线上,符合设计要求。基于有限元模型研制超声波切割刀,通过阻抗分析仪与激光多谱勒测振仪对换能器的固有频率与响应进行测试,获得的超声切割刀阻抗曲线平滑,谐振频率为40.261 kHz,设计误差为0.83%,最大振幅达到14.52 μm,结果与有限元计算相互吻合。     

高动态位移ScAlN基超声换能器的设计及制作

超声探测作为重要的感知技术,其探测性能一直是学术界研究的热点。针对薄膜超声换能器谐振位移低,导致输出声压较低,从而影响探测性能的问题,该文提出了一种高动态位移的薄膜ScAlN基超声换能器结构,该结构直径为360 μm,中心处膜层由4根悬梁支柱固支,通过微机电系统（MEMS）微纳加工技术制作了换能器阵列。测试结果表明,该器件谐振频率下,中心处动态位移可达2.16 μm/V。此外,该结构使膜层振动模态转变为输出声压更高的活塞型模态,相关工作为空气介质中长距离超声测距传感器的研究奠定了基础。     

脉冲频率对油漆漆层激光清洗作用机制的影响

针对表面涂有150 μm厚环氧基底漆涂层的2024铝合金,采用不同脉冲频率的纳秒脉冲激光进行激光清洗试验,分析了激光清洗后试样的表面形貌、表面粗糙度、清洗厚度以及清洗机理等.试验结果表明:表面粗糙度(Ra)受频率的影响较小且在3 μm左右.计算了不同脉冲频率下的清洗深度,结果发现,当频率为10 kHz时,清洗深度约为130 μm.通过数值模拟分别研究了激光清洗过程中脉冲频率对烧蚀机制中烧蚀量和剥离机制中热应力的影响.数值模拟结果表明:烧蚀量随着频率的增大而降低,在5～25 kHz范围内烧蚀量的最大降幅超过9％;通过最大热应力与脉冲能量密度的线性拟合计算得到剥离机制的触发阈值约为1.64 J/cm2;在脉冲能量密度高于1.64 J/cm2的条件下,频率越高,越难积热,从而使得烧蚀机制越弱;越大的频率使得热应力超过结合力的频次更多,剥离机制增强,能获得更好的清洗效果.     

超声雾化系统的雾化性能测试

研究建立了超声雾化装置,用激光粒度仪测试了雾化液滴的粒径,并研究了雾化溶液加入量、超声雾化功率、载气流量等雾化参数对超声雾化速率及管路输运损失的影响。结果表明,雾化液滴的粒径约Ф2．6μm．在一定加液量范围内,加液量的变化对雾化速率影响不大,雾化速率随载气流量和雾化功率的增大而增大;而管路输运损失随载气流量的增大先减小,在载气流量为800cm^3／min附近达到最小后,再随载气流量的增大而增大．     

基于有限元模型的超声切割刀优化设计

超声切割刀在材料加工领域中有广泛的应用前景,可用于切割各种复合材料等硬脆材料。该文利用ANSYS有限元分析软件建立超声切割刀的有限元模型,对其进行模态分析和谐响应分析。仿真结果显示,超声切割刀在40kHz频率附近存在轴向纵振模态,其振动节点位于安装环和压电陶瓷中心线上,符合设计要求。基于有限元模型研制超声波切割刀,通过阻抗分析仪与激光多谱勒测振仪对换能器的固有频率与响应进行测试,获得的超声切割刀阻抗曲线平滑,谐振频率为40.261kHz,设计误差为0.83%,最大振幅达到14.52μm,结果与有限元计算相互吻合。     

弛豫铁电单晶超声电机的动态响应模拟与分析

相对于传统压电陶瓷,新型压电单晶材料铌镁酸铅-钛酸铅(PMNT)具有更优良的介电和压电性能。该文将PMNT单晶作为超声电机的驱动材料,引入二维弹性接触、预应力等因素建立数学模型。经Matlab软件对20mm超声电机进行模拟,其最大空载转速为383r/min,输入电压频率为50.3kHz。经过与实测结果对比,该模型能够较准确地模拟电机稳态运行时的性能参数。     

指数复合型低频压电雾化喷头的设计

设计一种频率为40 kHz的指数复合型低频压电雾化喷头,建立有限元模型,通过喷头模型的模态分析和谐响应分析来测定喷头模型的振动形态、谐振频率和雾化振幅。模态在八阶时喷头为纯拉伸状态,谐振频率为39 550 Hz,在设定电压为26 V时,仿真得到雾化振幅为3.9μm。采用德国Polytec高性能单点式激光测振仪测得喷头样机的振动幅值为3.94～4.32μm,误差小于10%,符合设计的要求。采用马尔文Spraytec型激光粒度仪对样机雾滴均匀性进行测量,当驱动电压为26 V时,喷头雾化产生的雾滴直径为SymbolFC@(30～95)μm,占比超过85%,结果表明,该喷头雾化液滴分布较均匀。     

粒径对BaTiO_3/Epoxy复合材料介电性能的影响

利用Landau-Ginzburg-Devonshire(LGD)热力学唯象理论计算了BaTiO3自发极化强度和有效介电常数与其粒径的关系,在1¹ 000nm范围内分别进行对数理论(Lich)、有效介质理论(MGT)、有效介质理论(EMT)和Jayasundere-Smith(J-S)修正理论拟合,得到了不同粒径下钛酸钡/环氧树脂(BaTiO3/Epoxy)复合材料的有效介电常数。研究表明,BaTiO3单一组分时,在粒径约300nm处有较高的室温有效介电常数;与Epoxy复合后,在BaTiO3体积分数较低(10%1 000nm范围内分别进行对数理论(Lich)、有效介质理论(MGT)、有效介质理论(EMT)和Jayasundere-Smith(J-S)修正理论拟合,得到了不同粒径下钛酸钡/环氧树脂(BaTiO3/Epoxy)复合材料的有效介电常数。研究表明,BaTiO3单一组分时,在粒径约300nm处有较高的室温有效介电常数;与Epoxy复合后,在BaTiO3体积分数较低(10%⁴0%)时由J-S理论计算的结果与实验值吻合良好。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.