Evanohm合金的双环线型微加热器特性研究

以Evanohm合金为材料,设计了一种双环线型微加热器.使用AC磁控溅射技术在硅基底上沉积合金薄膜,并采用微机电系统(MEMS)微加工工艺实现薄膜图形化,以此作为加热器的加热元件.在常温下,研究了所制备的薄膜加热器件的加热性能与电学特性,并在深低温下进一步测试了其电学性能.研究结果表明:此种微型加热器电阻值稳定.在[5...     

NiCr薄膜微加热器在低温环境下的电学特性研究

设计了一种适用于深低温环境的微型加热器。使用AC磁控溅射技术将NiCr(80/20 at.%)合金沉积到SiO2/Si基底上,并采用微加工工艺实现薄膜图形化,作为加热器的加热元件。研究了NiCr薄膜的电学性能和晶体结构与退火条件之间的关系。实验表明:在450℃氮气环境下退火30min,可以获得深低温性能优良的NiCr加热器。该加热器在20K时的电阻温度系数(TCR)为80.80×10-6/K。X射线衍射(XRD)分析显示NiCr薄膜在450℃氮气环境下退火后,薄膜的结晶度增大,因此,退火条件对薄膜的电阻率和电阻温度系数有较大的影响。     

超高密度相变存储的研究

相变存储被广泛应用于光信息技术中,比如DVD、CD-ROM等。目前相变存储也正在被考虑在非易失存储方面的应用。本文报道了相变材料的热存储优势,特别地,我们展示了存储密度为3.3Tb/in~2的可擦除热相变记录原理,该记录密度比目前的商业光存储技术可达到的存储密度高3倍。我们演示了薄膜纳米加热器的原理,这种薄膜加热器可以实现小于50纳米的超小加热斑点。最后,我们展示了一种示例,薄膜加热器能够以非常高的速度写、擦除、读取存储材料的相位。该文章为基于相变材料的高密度光存储技术提供了重要的前进基石。     

基于喷墨打印的可实现敏感材料原位沉积和高温检测的柔性丙酮气体传感器

通过离子交换技术对衬底表面改性,然后喷墨打印掩膜图形,在聚酰亚胺衬底两面分别制备了银叉指电极和加热电阻.通过调节电阻加热器两端的直流偏压,实现25 ℃~280 ℃的控温加热.集成的加热器具有双重功能:纳米ZnO敏感薄膜原位沉积和高温检测.结果表明,该传感器对丙酮气体的灵敏度随温度单调增加(<150 ℃).此外,加热器促进了ZnO敏感薄膜表面丙酮气体分子的解吸,缩短了传感器响应和恢复时间,并减小了初始电阻的漂移.此外,在丙酮检测中,加热器能有效地减少湿度干扰.     

金属薄膜加热器的研究

采用射频溅射方法制备了Cr和Ni-Cr(Ni:80%,Cr:20%)金属薄膜,探讨了热处理温度和时间对Cr薄膜电阻温度系数和电阻率的影响.在一定直流电压条件下,Ni-Cr和Cr薄膜微型加热器的加热温度可达到100℃,且升温速率皆大于0.50C/s.通过测量微加热器的电阻温度曲线,表明所制备的金属薄膜式微型加热器具有较好的稳定性和重复性,能够满足PCR生物芯片和硅基热分布式微流量传感器的要求.     

双加热探空仪湿度传感器的加热控制研究

利用双加热探空仪电容湿度传感器加热前后相对湿度和温度、露点、饱和水汽压间的关系,分析和建立了去除加热器影响的实际相对湿度的计算方法。采用模糊RBF神经网络PID控制方法对加热器进行控制,从而避免了繁琐的依靠人工实验整定PID参数的过程。Matlab仿真结果表明:同采用Niegler-Nichols经验公式的传统PID控制器相比,模糊RBFPID控制器具有更好的稳定性和更快的响应速度,其阶跃响应超调分别为15.1%,4.3%,允许误差为2%的调节时间分别为7.12,3.8 s。     

多轴联合循环机组GE燃机进气加热控制方法研究

多轴联合循环机组GE燃机进气加热由于未有效冲刷性能加热器,导致加热无法在短时间内达到加热温度,并且发电功率较低,因此,研究了一种多轴联合循环机组GE燃机进气加热控制方法。该研究将天然气作为多轴联合循环机组GE燃机的进气气体,提出兼备进气冷却与进气加热的GE燃机进气加热控制方案,该方案中通过性能加热器进行进气加热控制,在性能加热器加热控制前冲刷处理性能加热器,使水侧管线进入热待用形态并避免水侧管线发生遗漏,并在加热控制阶段采用PID算法实现多轴联合循环机组GE燃机进气加热控制。实验表明：该方法可在短时间内使多轴联合循环机组GE燃机进气温度达到目标温度;应用该方法可以提升多轴联合循环机组GE燃机发电功率及发电效率,当进气加热温度为35℃时联合循环机组负荷率降低程度、发电效率提升程度最大。     

基于MEMS的镍薄膜加热器催化传感器研究

设计了基于微机电系统(MEMS)工艺,以镍薄膜作为加热体的新型催化传感器。通过磁控溅射沉积、刻蚀等工艺制成镍薄膜加热器,并对其进行了稳定化热处理以及防氧化聚合物涂层处理。传感器性能测试结果表明:镍薄膜加热器具有良好的抗高温氧化能力;气氛老化可缩短50%的老化时间;甲烷气体浓度与灵敏度呈良好的线性关系;对甲烷的灵敏度约为30 m V/1%Vol;传感器功耗约为150 m W,零点和灵敏度年漂移小于1. 5%LEL。     

集成加热功能高分子电容式湿度传感器研究

针对高空气象探测领域中温湿度骤变产生水分凝结而影响测量精度问题，开展了集成加热功能的湿度传感器研究，通过仿真手段，优化了加热器结构；通过对感湿膜成膜工艺进行研究，提高了传感器灵敏度、降低了湿滞和响应时间；通过将MEMS工艺与有机薄膜成膜工艺相结合，实现了湿度传感器制作。按照湿度传感器测试方法进行了性能测试，结果表明，该湿度传感器灵敏度> 0.40 pF/%RH、湿滞<1.5%RH、非线性<1.5%、响应时间<2 s；对加热器除湿能力进行了试验，结果表明，启动加热2 s即可有效去除湿度传感器表面的液态水滴。     

模糊控制在加热炉上的应用

介绍了加热炉模糊控制系统完全用模糊控制代替常规的PID算法,并构成串级并联控制系统对加热炉的加热温度进行控制,结果表明：抗干扰能力强,精度高,节省了能源,保护了环境,取得了良好的调节品质。     

MEMS-based formaldehyde gas sensor integrated with a micro-hotplate

This paper presents a novel micro-fabricated formaldehyde gas sensor with enhanced sensitivity and detection resolution capabilities. The device comprises a quartz substrate with Pt heaters as a micro-hotplate and deposited formaldehyde-sensing layer on it. A sputtered NiO thin film is used as the formaldehyde-sensing layer. A specific orientation of NiO becomes more apparent as the substrate temperature increases in the sputtering process, which helps the formation of NiO material with a correct stoichiometric ratio. The gas sensor incorporates Pt heating resistors integrated with a micro-hotplate to provide a heating function and utilizes Au inter-digitated electrodes. When formaldehyde is present in the atmosphere, oxydation happens near the sensing layer with a high temperature caused by the micro-hotplate and causes a change in the electrical conductivity of the NiO film. Therefore, the measured resistance between the inter-digitated electrodes changes correspondingly. The application of a voltage to the Pt heaters causes the temperature of the micro-hotplate to increase, which in turn enhances the sensitivity of the sensor. The nanometer scale grain size of the sputtered oxide thin film is conducive to improving the sensitivity of the gas sensor. The experimental results indicate that the developed device has a high stability (0.23%), a low hysteresis value (0.18%), a quick response time (13.0 s), a high degree of sensitivity (0.14 Ω ppm^?1), and a detection capability of less than 1.2 ppm.     

MEMS-based formaldehyde gas sensor integrated with a micro-hotplate

This paper presents a novel micro-fabricated formaldehyde gas sensor with enhanced sensitivity and detection resolution capabilities. The device comprises a quartz substrate with Pt heaters as a micro-hotplate and deposited formaldehyde-sensing layer on it. A sputtered NiO thin film is used as the formaldehyde-sensing layer. A specific orientation of NiO becomes more apparent as the substrate temperature increases in the sputtering process, which helps the formation of NiO material with a correct stoichiometric ratio. The gas sensor incorporates Pt heating resistors integrated with a micro-hotplate to provide a heating function and utilizes Au inter-digitated electrodes. When formaldehyde is present in the atmosphere, oxydation happens near the sensing layer with a high temperature caused by the micro-hotplate and causes a change in the electrical conductivity of the NiO film. Therefore, the measured resistance between the inter-digitated electrodes changes correspondingly. The application of a voltage to the Pt heaters causes the temperature of the micro-hotplate to increase, which in turn enhances the sensitivity of the sensor. The nanometer scale grain size of the sputtered oxide thin film is conducive to improving the sensitivity of the gas sensor. The experimental results indicate that the developed device has a high stability (0.23%), a low hysteresis value (0.18%), a quick response time (13.0 s), a high degree of sensitivity (0.14 Ω ppm⁻¹), and a detection capability of less than 1.2 ppm.

     

数字电影制作过程的视觉效果质量控制

介绍了数字电影后期制作过程中视觉效果质量控制方面的问题,分析了制作环节视觉效果的影响因素,并提出了实用的测量方法和仪器。同时为了建立一个有效的模型来比较不同媒体图象记录和复现的视觉效果质量,还讨论了不同设备的图象复现能力和特性,以曲线确定而非简单公式转换等一系列非线性因素。对每种因素和设备的调整参数采用由软件计算出来的查找表。并开发出一个适用于数字电影制作工作室设备校准、系统调试和图象质量测量的视觉效果管理系统。     

Electro-thermal simulation and characterization of preconcentration membranes

We use electro-thermal simulations to design thermally insulated membranes that support thin film heaters as components of gas preconcentrators. These heaters provide a good thermal homogeneity ensuring a narrow desorption peak and, thus, a good sensor response. Temperature measurements have been carried out using an infrared camera and they are in agreement with the corresponding numerical predictions. Our model has been validated and it can be used in future designs.     

Depletion of monolayer liquid lubricant films induced by high-frequency pulsed-laser heating in thermally assisted magnetic recording

In this study, lubricant depletion due to high-frequency pulsed-laser heating was investigated for lubricant films with thicknesses of both more than and less than one monolayer. A conventional lubricant, Zdol2000, was used. It was found that the critical temperature at which the lubricant begins to deplete owing to laser heating was strongly dependent on the lubricant film thickness. In the case in which the thickness of the lubricant film was less than one monolayer, this temperature was approximately 170?°C higher than it was when the thickness was more than one monolayer. To analyze the lubricant depletion mechanism, we examined the tested lubricant film using temperature programmed desorption (TPD) spectroscopy. It was found that the lubricant depletion characteristics due to laser heating could be explained using the experimental TPD results for the tested lubricant film, and that the depletion mechanism involves the desorption or decomposition of the lubricant molecules, which interact with the diamond-like carbon thin films when the lubricant film thickness is less than one monolayer. Further, the results of TPD and of a thermogravimetric analysis (TGA) of the lubricant were compared. The thermal robustness of the ultra-thin liquid lubricant films was found to be greater than that of the bulk lubricant materials.     

Fabrication and characterization of MEMS-based flow sensors based on hot films

The purpose of this paper is to propose two types of airflow velocity measurement modules, double-chip and single-chip, of MEMS-based flow sensors that consisting of heating resistors and sensing resistors on alumina substrates. In this study, MEMS techniques are used to deposit platinum films on the substrate to form resistors which are to regard as heaters and sensing elements. As air flows through the heater and the sensor, the temperature of the sensing resistor on the hot film decreases and the changes of the local temperature determine the airflow rate. The experimental results show the resistance linearly varies as airflow velocity changes from 5 to 28 ms⁻¹. Finally the experimental data indicate that sensing performance of the single-chip type is better than that of the double-chip type with its higher sensitivity (0.7479 Ω/ms⁻¹) due to the more rapid heat conduction from the heating resistor to the sensing resistor.     

Design and optimization of heating plate for metal oxide semiconductor gas sensor

A thin film was coated onto the top of the heating electrodes to reduce the power consumption and improve the uniformity of temperature distribution. Finite element simulation software COMSOL was used to simulate the effect of coating materials and dependence of thicknesses of the coating film on the power consumption of the heating plate. On the basis of simulation, the temperature distribution of different heating plates was measured using infrared thermography. Experiments have showed that the power consumption of the heating plate can be significantly reduced and the temperature uniformity is promoted with adding the coating film on the top of the heating electrodes. The response of the gas sensor based on PdO-WO₃ nanoparticles was characterized with analyte of acetone. It was found that the addition of the coating film could enhance the response to acetone. In addition, the response speed of sensors was investigated with coating films and the results indicated that with the coating film sensor response speed became faster.

     

求解整数线性规划问题的定界阻止算法的改进*

在现有求解整数线性规划问题的定界阻止算法的基础上提出了一种改进。该算法通过目标函数超平面截线性规划松弛问题的有效约束锥而形成一个单纯形;然后,引入一串平行片来切割该单纯形产生更低维的凸多面体;最后,在片上的这些凸多面体上执行阻止搜寻程序。由于单纯形和片上凸多面体的极顶点可以直接通过公式计算,且变量在片上凸多面体上的取值区间更窄,改进的定界阻止算法既方便又高效,这得到了一些经典算例和随机产生的算例的验证。     

The design and fabrication of polymerase chain reaction platform

Thermalcycler was extensively used machine for amplify DNA sample. One of the major problems in the working time was that it spent most of time for cooling and heating. In order to improve the efficient, the study presented a novel method for amplify DNA sample. For this concept, the DNA sample in the silicon chamber which was pushed by a tappet through the three temperature regions around a center and then the DNA segments could be amplified rapidly after 30 cycles. The polymerase chain reaction (PCR) platform was composed of the thin-film heaters, Cu plates, DC powers, and temperature controllers. The photolithography and bulk etching technologies were utilized to construct the thin-film heater and DNA reaction chambers. Finally, 1 μl 100 bp DNA segment of Escherichia coli K12 was amplified successfully within 36 min on this PCR platform.     

Simulation and experimental validation of a SU-8 based PCR thermocycler chip with integrated heaters and temperature sensor

We present a SU-8 based polymerase chain reaction (PCR) chip with integrated platinum thin film heaters and temperature sensor. The device is fabricated in SU-8 on a glass substrate. The use of SU-8 provides a simple microfabrication process for the PCR chamber, controllable surface properties and can allow on chip integration to other SU-8 based functional elements. Finite element modeling (FEM) and experiments show that the temperature distribution in the PCR chamber is homogeneous and that the chip is capable of fast thermal cycling. With heating and cooling rates of up to 50 and 30 °C/s, respectively, the performance of the chip is comparable with the best silicon micromachined PCR chips presented in the literature. The SU-8 chamber surface was found to be PCR compatible by amplification of yeast gene ribosomal protein S3 and Campylobacter gene cadF. The PCR compatibility of the chamber surfaces was enhanced by silanization.