基于MEMS技术的微型气相色谱柱的研制

描述了一种采用MEMS技术加工的微型气相色谱柱，这种色谱柱采用深刻蚀技术加工出色谱通道，再与Pyrex7740玻璃进行键合密封。色谱柱全长6m，色谱通道截面为矩形（宽100μm，深100μm），针对苯和甲苯的混合气进行了分离试验，理论塔板数达到了4800，分离时间为185s。     

基于MEMS技术的微型气相色谱柱的研制

描述了一种采用MEMS技术加工的微型气相色谱柱,这种色谱柱采用深刻蚀技术加工出色谱通道,再与Pyrex 7740玻璃进行键合密封.色谱柱全长6 m,色谱通道截面为矩形(宽100 μm,深100 μm),针对苯和甲苯的混合气进行了分离试验,理论塔板数达到了4800,分离时间为185 s.     

用于恶臭气体检测的微型气相色谱柱的研发

基于微流控芯片的微型气相色谱柱可实现对微量恶臭气体的快速有效检测。给出了微流控芯片上微型气相色谱柱的检测机理和实验数据。该芯片利用喷砂加工技术在尺寸为115 mm×60 mm×6 mm硼硅酸玻璃晶圆上加工出半圆截面的S形微通道,再用热键合技术将具有同样沟槽的两基片对接,得到内径为1 mm的圆形截面沟槽,沟槽有效长度为1.8 m。根据恶臭气体的性质,在沟槽表面涂敷聚乙二醇作为固定相。所开发的芯片对丙酮气体的检测要优于不锈钢色谱柱。利用该芯片进一步对丙酮和乙醇混合气体进行分离实验,分离度可达3.1,分离性能良好。     

微型色谱柱制备及其GC谱线分离性能的优化

基于激光刻蚀加工技术设计并制备了新型蛇形沟道布局微型色谱柱芯片,采用硅材料衬底刻蚀加工,设计并制备了不同沟道布局的微型色谱柱,并对混合组分进行分离分析.选取成本较低、加工周期较短的紫外激光刻蚀进行微型色谱柱制备,并针对实验得到的色谱图存在的重叠峰问题,利用连续小波变换提取色谱重叠峰的特征点,构建反映重叠峰前肩峰、后肩峰...     

MEMS微型气相色谱分离柱结构的研究进展

气相色谱分离柱是色谱系统的重要组件之一,采用MEMS技术制作的微型气相色谱分离柱与传统分离柱相比,因其具有较小的平面二维结构和快速分离混合物的能力而备受青睐。对MEMS微型气相色谱分离柱结构的研究进展进行了综述,将硅基底材料制作的分离柱结构分为螺旋型、直线型、蛇型和阵列型,重点从组分分离时间、分辨率和理论热塔板数等方面对微型色谱分离柱的各种结构进行了综合分析和比较,并介绍了新兴工艺制作的镍基底、聚合物基底和PECVD薄膜基底的微型气相色谱分离柱。     

基于MEMS技术的微型气相色谱柱的研究进展

微型气相色谱柱是基于MEMS技术的微型分析化学器件,主要用于混合化学组分的分离,采用MEMS技术制作的微 型气相色谱柱在体积上得到了极大的缩小,便于集成到便携式设备中,其次,微型器件带来更小的热容量,因而能在更小的功 耗下获得更快的升温速率,从而加快了分析速度,进而改进了器件的整体性能.针对MEMS微型气相色谱柱的研究...     

数值模拟毛细管通道中微粒的介电泳分离

基于直流介电泳技术,采用一种具有三维突扩、突缩截面的新型毛细管式微通道,对直径分别为8和12μm的聚苯乙烯微粒在通道中的分离进行数值模拟。分析了微粒受到的电渗力、电泳力和介电泳力对其运动轨迹的影响。数值模拟结果表明,聚苯乙烯微粒在突扩、突缩截面附近受到负介电泳力作用,运动轨迹不断向通道轴心偏移;电渗力和电泳力的作用方向相反,有效降低了微粒的运动速度,增加了介电泳力的作用时间。外加电压100 V时,可最有效地将直径为8μm微粒输运至出口内置套管外,而直径为12μm的微粒被出口内置套管接收,实现不同尺寸聚苯乙烯微粒的连续分离。     

PMMA基连续流式PCR微流控芯片的CO2激光直写加工与应用

采用CO2激光直写烧蚀加工技术在聚甲基丙烯酸甲酯(PMMA)基片表面加工微通道.分析了CO2激光输出功率和激光束移动速度对加工质量的影响.选用4.5 W输出功率和76.2 mm/s移动速度,在30 s内加工了水力直径为100μm的微通道.在进行微通道的大批量、快速加工时,CO2激光直写烧蚀加工技术具有较高的工艺稳定性,工艺流程简单,可随时根据实验需要时微通道结构进行调整和再加工.微通道的激光拉曼光谱与PMMA基片相同,保证了微通道和盖片对聚合酶链式反应(PCR)物化学影响的一致性.虽然微通道边缘存在少量重铸物,但不会影响热压键合效果.芯片能够满足PCR扩增中的压力与密封要求.使用这种芯片实现了180 bp拟南芥脱氧核糖核酸(DNA)片段的PCR扩增,扩增效果与使用常规PCR仪相当,验证了采用CO2激光直写烧蚀方法加工PMMA基连续流式PCR微流控芯片的可行性.     

基于体硅MEMS技术的悬浮微结构加工工艺研究

针对体硅MEMS加工技术的特点,确定了悬浮微结构的加工工艺流程,并对加工过程中的硅基深槽腐蚀工艺和ICP刻蚀工艺这两项关键技术及其中的重要影响因素进行了研究,得到了硅基深槽腐蚀的溶液类型、浓度和温度等工艺参数,以及ICP刻蚀工艺的功率、气体流量等工艺参数。根据优化的工艺参数,采用厚度为400μm的N型<100>硅片加工了外形尺寸为3 mm×3 mm、线宽尺寸为100±2μm、硅槽深度为390±2μm的悬浮微结构样件。     

快速气相色谱/电子轰击离子源-飞行时间质谱联用仪的研制

基于快速气相色谱分析技术和飞行时间质谱技术,研制了快速气相色谱/电子轰击离子源-飞行时间质谱联用仪。仪器由进样系统、气相色谱分离系统、气质接口、电子轰击离子源、垂直引入反射式飞行时间质量分析器、数据采集系统和硬件控制系统等组成。设计了汽化室、加热膜色谱柱和一种三层套管的传输管用于连接色谱与质谱。以烃类混合标准气体为对象,对载气压力、色谱柱温度和电压参数进行了优化,实现了对各类有机物的快速分离和准确定性。最后,将该方法用于测试苯系物和异丁烷标气,进行了仪器性能测试。结果表明,质量范围是4~502 amu,分辨率优于500(FWHM),检测限为500 ppb,分析时间小于5 min,重现性RSD小于10%,动态范围达到四个数量级。     

Effect of Al trace dimension on electromigration failure time of flip-chip solder joints

The effect of Al-trace dimension on electromigration of flip-chip solder joints was investigated. The Al trace dimension was found to have a significant influence on the electromigration failure time. When joints with Al traces 100 μm wide were stressed by 1.0 A at 100°C, failure times were 35 h, 1,700 h, and >3,000 h for joints with Al traces that were 2,550 μm, 1,700 μm, and 850 μm long, respectively. Solder joints with Al traces 40 μm wide and 2,550 μm long failed instantly at 0.6 A. The Joule heating effect was found to be responsible for the huge difference in failure time.     

An Approach to Linear Scalable DH-PHEMT Model for Millimeterwave Application

This paper describes a scalable small-signal equivalent circuit for 0.25 μm gatelength Double Heterojunction delta-doped PHEMTs. The scaling rules for all elements except the pad capacitances and bondwire inductances have been determined. Good agreement is obtained between simulation results and measured results for 2 times 20 μm , 2 times 40 μm, 2 times 60 μm, 2 times 100 μm gate width (number of gate fingers times unit gate width) DH PHEMT.     

双包层光纤侧面耦合器

研究了一种侧面抽运双包层光纤的方法,从被剥除了外包层、端面为350μm×400μm的D型双包层光纤内包层上切下长度为3mm的一段柱体,并胶合在相同的双包层光纤内包层的侧面上,构成了柱体-光纤侧面耦合器。半导体激光器的抽运光从该柱体的一端入射并通过它耦合进入双包层光纤的内包层,实验测得耦合器最大耦合效率为85%。该方法适用于输出功率为数瓦的光纤激光器和放大器的侧面抽运。     

微型笔直写制备厚膜阻性元件技术研究

为了实现电子元器件的快速制备,设计并实现了一种微型笔直写装置。利用该装置进行了电阻浆料的直写制备。研究了直写电阻元件的工艺特点、表面形貌和性能。得到了优化的工艺范围:笔头通径100～450μm,笔头到基板表面距离8～20μm,电阻高温烧结之后线宽100～500μm,膜厚5～15μm。所直写的电阻边缘整齐,表面较平整,烧结后,方阻约为0.92 kΩ/□。     

Screen printed thick film nickel-silicon interaction

This paper reports the interaction of screen printed thick film nickel with N-Si (100), 3–6 Ωcm resistivity both unoxidised and oxidised with windows defined into it. The nickel film after printing was air dried at 150°C for 10 min and finally air fired at 550, 650, 750 and 850°C in a conveyor furnace with 60 min cycle. The high temperature firing yielded the minimum sheet resistance of 55 mΩ/. The barrier heights and the ideality factors were 0.74, 1.5; 0.70, 1.0; 0.69, 1.0; and 0.73, 2.8 at the above temperatures. The contact resistance was found to be lowest, i.e. 90 Ωcm² at the firing temperature of 850°C. The SEM combined with EDS of the top surface and the cross sections of the interface revealed (1) the lead from the printed line flows by 40 μm and 100 μm at firing temperatures of 750 and 850°C respectively, (2) the interface reaction zone consisting of Ni₂Si is uniform and is 1 μm thick. However, at 850°C a few V-grooves 5 μm × 5 μm filled with lead and nickel are generated. The possible applications of the interactions are suggested.     

连续Nd∶YAG稳频倍频激光器

在连续稳频Nd:YAG激光器的基础上,重新设计了腔形,使用角度匹配的KTP和MgO:LiNbO_3晶体倍频。在输入功率为2.5kW时,获得基频光800mW输出,强度波动小于2％,频率稳定性优于2MHz。同时获得50～100mW的倍频光输出,强度波动小于5％,频率稳定性优于5MHz。     

Miniaturized continuous-flow polymerase chain reaction microfluidic chip system

A miniaturized continuous-flow polymerase chain reaction (PCR) microfluidic chip system was developed to perform DNA amplification. This system consists of a 20-cycle continuous-flow PCR microfluidic chip, an electrical heating system and a miniature air pressure-vacuum pump. The chip was ablated with excimer laser direct-writing micromachining technique on a polymethyl methacrylate (PMMA) sheet. The ablated microchannel was inverse trapezoidal with a depth of 70 μm, top width of 200 μm and bottom width of 120 μm. Its surface roughness Ra was 1.42 μm after being treated with excimer laser polishing. The substrate sheet ablated with the microchannel was bonded with other cover sheets using hot-press bonding method to form a closed structure. The electrical heating system consisted of three groups of heating membranes, Pt100 sensors, copper blocks and PID temperature digital controllers. It could provide three distinct maintained temperature zones and a uniform temperature distribution in each zone. PCR amplification of a 170 base pair (bp) DNA fragment was carried out to validate the system's feasibility. The PCR temperatures were set as 94℃ for denaturation, 55℃ for primer annealing and 72℃ for extension. The flow rate in the microchannel was 40 nL/s and the total time for the completion of a 20-cycle amplification of 20 μL reagent was 15 min.     

MEMS磁芯螺线管微电感的制作工艺研究

采用微机电系统(MEMS)技术制作了磁芯螺线管微电感,该技术包括UV-LIGA、干法刻蚀技术、抛光和电镀技术等。研制的微电感大小为1500μm×900μm×100μm,线圈匝数为41匝,宽度为20μm,线圈之间的间隙为20μm,高深宽比为5∶1。测试结果表明:在1～10MHz频率下,其电感量为0.408～0.326μH,Q值为1.6～4.2。     

64×64元InSb红外焦平面读出电路研制进展

研制了用于 6 4× 6 4元InSb红外焦平面的几种读出电路。ISM 6 4× 6 4- 2型电路是采用直接注入模式 ,行积分工作的读出电路。ISM 6 4× 6 4- 3型电路仍然采用直接注入读出模式 ,行积分工作 ,但是增加了一级采样保持电路。ISM 6 4× 6 4- 4型电路采用直接注入模式 ,帧积分工作 ,因而可大大提高信噪比。描述了 2、3和 4型电路的结构 ,工作原理及版图设计特点 ,电路的制造工艺、测试方法及其主要性能。     

Infrared Optical Characterization of PLT Thin Films for Applications in Uncooled Infrared Detectors

Lanthanum-modified lead titanate (PLT) thin films have been grown directly on Pt/Ti/SiO₂/Si (100) and LaNiO₃/Si (100) substrates by a modified sol-gel method. X-ray diffraction analysis shows that the PLT thin films are polycrystalline. The infrared optical properties of the thin films were investigated using infrared spectroscopic ellipsometry (IRSE) in the spectral range of 2.5–12.5 μm. By fitting the measured ellipsometric parameter (tan Ψ and cosΔ) data with a three phase model (air/PLT/Pt) for the PLT thin films on Pt/Ti/SiO₂/Si (100) and a four phase model (air/PLT/LNO/Si) for the PLT thin films on LaNiO₃/Si (100) substrates, and a derived classical dispersion relation for the thin films, the optical constants and thicknesses of the thin films have been simultaneously obtained. The refractive index and extinction coefficient of the PLT thin films on Pt/Ti/SiO₂/Si (100) substrates are slightly larger than those on LaNiO₃/Si (100) substrates. Given the infrared semitransparent metal of Nickel currently used, the absorption of the Ni/PLT/Pt and Ni/PLT/LNO/Si multilayer thin films in this study is very large around 3.0 μm and 5.7 μm wavelength range and decrease to 15% or 20% in the 8–12.5 μm wavelength region.