共查询到20条相似文献,搜索用时 46 毫秒
1.
K. Boboridis 《International Journal of Thermophysics》2002,23(1):277-291
A microsecond-resolution technique was used to measure the heat of fusion, specific heat capacity, and electrical resistivity of niobium and titanium in the temperature range of 1600 to 3200 and 1500 to 2200 K, respectively. The method is based on rapid resistive self-heating of a wire-shaped specimen by a current pulse from a capacitor–discharge system. Melting of the specimen occurs in approximately 50 s. Measured quantities are the current through the specimen, the voltage across the specimen, the radiance from the specimen, and its normal spectral emittance, as functions of time. The true temperature of the specimen is computed from the values of the normal spectral emittance and radiance temperature of the specimen at each instant. The latter quantities are measured by means of high-speed laser polarimetry and radiation thermometry, respectively. 相似文献
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Benjamin K. Tsai 《Journal of research of the National Institute of Standards and Technology》2006,111(1):9-30
During the last 10 years, research in light-pipe radiation thermometry has significantly reduced the uncertainties for temperature measurements in semiconductor processing. The National Institute of Standards and Technology (NIST) has improved the calibration of lightpipe radiation thermometers (LPRTs), the characterization procedures for LPRTs, the in situ calibration of LPRTs using thin-film thermocouple (TFTC) test wafers, and the application of model-based corrections to improve LPRT spectral radiance temperatures. Collaboration with industry on implementing techniques and ideas established at NIST has led to improvements in temperature measurements in semiconductor processing. LPRTs have been successfully calibrated at NIST for rapid thermal processing (RTP) applications using a sodium heat-pipe blackbody between 700 °C and 900 °C with an uncertainty of about 0.3 °C (k = 1) traceable to the International Temperature Scale of 1990. Employing appropriate effective emissivity models, LPRTs have been used to determine the wafer temperature in the NIST RTP Test Bed with an uncertainty of 3.5 °C. Using a TFTC wafer for calibration, the LPRT can measure the wafer temperature in the NIST RTP Test Bed with an uncertainty of 2.3 °C. Collaborations with industry in characterizing and calibrating LPRTs will be summarized, and future directions for LPRT research will be discussed. 相似文献
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红外辐射温度计在低温测量的辐射源尺寸效应(SSE) 的规律不同于高温测量。基于以虚拟探测器温度消除背景辐射影响的SSE计算模型,推导了在不同源尺寸和不同背景条件下辐射温度计输出的SSE影响修正公式;得出不同源尺寸条件下辐射温度计温度示值的SSE影响修正的理论解析表达式。在源温度低于或接近背景温度时修正模型与高温测量SSE修正模型有显著差异。所得结果适用于任意温度下对单波段辐射温度计的SSE影响修正。 相似文献
4.
本简要介绍了所研制的红外辐射式体温计的构成及标定实验方法;研究了环境温度对体温计的影响;并在实验基础上提出了采用分段标定及对环境温度补结果进行修正的方法,提出了测量精度。 相似文献
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坦克动力舱装甲板红外辐射温度计算分析 总被引:3,自引:0,他引:3
建立了坦克动力舱装甲板温度场数值计算模型,针对坦克动力舱装甲板的红外特性进行了理论计算.采用耦合计算方法计算了装甲板的温度场,通过装甲板和空气双向耦合换热计算,并考虑太阳辐射对装甲板温度场的影响,预测了装甲板温度场分布和辐射强度分布.动力舱装甲板温度场的计算结果与测试结果的相对误差小于9.034%,基本满足工程设计的需要.研究结果表明,动力舱顶装甲板是主要辐射源,排气百叶窗和排气管附近顶装甲板是坦克的红外辐射特征明显区域. 相似文献
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This work presents a scanning laser-based thermal diffusivity measurement technique for thin films as well as for bulk materials. In this technique, a modulated laser beam is focused through a transparent substrate onto the film–substrate interface. The generated thermal wave is detected using a fast-responding thermocouple formed between the sample surface and the tip of a sharp probe. By scanning the laser beam around the thermocouple, the amplitude and phase distributions of the thermal wave are obtained with micrometer resolution. The thermal diffusivity of the film is determined by fitting the obtained phase signal with a three-dimensional heat conduction model. Experimental results are presented for a 150-nm gold film evaporated on a glass substrate. 相似文献
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C. Ronchi W. Heinz M. Musella R. Selfslag M. Sheindlin 《International Journal of Thermophysics》1999,20(3):987-996
This paper presents a new experimental technique enabling thermophysical measurements to be carried out at very high temperatures in a very simple and small pressurized vessel in which the sample is heated by a continuous wave laser, and subsequently subjected to a short temperature pulse. The adopted method is essentially an extension of the laser-flash technique, widely used for thermal diffusivity measurements, whereby, in addition, the heat capacity and, hence, the thermal conductivity, , are simultaneously evaluated from the pulse analysis. Results are presented for the thermal diffusivity and heat capacity of graphite, zirconia, and uranium dioxide up to temperatures above 3000 K. 相似文献
9.
Middle Temperature Scale for Infrared Radiation Thermometer Calibrated Against Multiple Fixed Points
The NMIJ has established a temperature scale for infrared radiation thermometry from 100 to 420°C consisting of three fixed-point
blackbodies at the In, Sn, and Zn points and an InSb detector thermometer at a wavelength of 4.7 μm. The blackbody cavities
have large openings of 15 mm diameter. The expanded uncertainties (k = 2) of the In, Sn, and Zn fixed-point radiance temperatures are estimated to be 0.03, 0.03, and 0.05 K, respectively. The
expanded uncertainties (k = 2) for the calibration of the infrared radiation thermometer are estimated to be 0.04 K at 157°C (In point), 0.04 K at
232°C (Sn point), and 0.07 K at 420°C (Zn point). 相似文献
10.
H. W. Yoon C. E. Gibson V. Khromchenko G. P. Eppeldauer R. R. Bousquet S. W. Brown K. R. Lykke 《International Journal of Thermophysics》2008,29(1):285-300
The construction, the calibration, and the use of the NIST Thermodynamic Radiation Thermometer (TRT) to measure the temperature
of the gold freezing temperature blackbody and a variable-temperature blackbody from 800 to 2,700°C are described. These temperature
determinations are detector-based and derived from the electrical substitution radiometer and length units. The TRT is constructed
using a cooled, near-infrared enhanced silicon detector with a room-temperature-stabilized five-position filter wheel. The
characteristics of the TRT, such as the size-of-source effect and preamplifier linearity, are determined. The measured temperatures
are compared with those obtained using the NIST Absolute Pyrometer 1 (AP1) and the current NIST standard radiation thermometer,
the Photoelectric Pyrometer (PEP). After the performance assessments, the TRT will become the standard radiation thermometer
for disseminating radiance temperature scales in the United States. 相似文献
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用典型红外辐射温度计的辐射源尺寸效应的实验数据说明不同测量条件下的检定/校准结果的差异可能为其最大允许误差绝对值的数倍。提出具有明确测量条件的平面辐射源瞄准模型和以辐射源前置光阑的方式对于不同空腔黑体辐射源实现相同的等效平面源直径的方法,提出了对光阑的技术特性和放置距离要求,分析表明低温辐射源对光阑的冷却作用可能引起不可忽略的示值降低。采用等效平面源模型的实验结果表明以不同几何条件的空腔黑体辐射源可得到一致的检定结果。讨论了应用平面辐射源模型可能遇到的实际技术问题和解决的对策。 相似文献
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The thermal diffusivity of thin metal films has been measured by combining a fast infrared radiation thermometer with a mercury cadmium telluride (MCT) detector and a CO2 laser modulated at a radio frequency up to 2 MHz. The laser output beam modulated by an acousto-optic modulator (AOM) is directed to the front surface of the blackened copper thin film (10m thick, 9.5 mm in diameter). The thermal radiation from the back surface of the sample is detected. From the observed phase delay in the detected signal of 0.68 radian to the input laser beam, the thermal diffusivity is determined to be 1.11 × 10-4m2·s-1, which agrees well with the value of 0.99 × 10-4m2·s-1 calculated from literature results. The method is generally applicable for measurements of thermal properties of nano/micro materials.Paper presented at the Fifteenth Symposium on Thermophysical Properties, June 22--27, 2003, Boulder, Colorado, U.S.A. 相似文献
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基于OpenFlight模型的通用桥梁红外辐射特性模拟方法 总被引:1,自引:0,他引:1
对桥梁结构进行分析及简化,提出了基于OpenFlight模型的通用桥梁建模方法,将梁式桥、斜拉索桥、拱桥和悬索桥统一为一种通用的模型结构,并分别针对桥梁箱体结构、主缆、索塔、护栏等典型部件的热特性,综合考虑各种自然因素,建立桥梁红外辐射特性计算理论模型,并以图像的灰度信息模拟红外辐射特性,开发了通用的桥梁红外辐射特性计算及成像仿真软件系统,实现了任意时刻、任意地理位置、任意气象条件下不同类型桥梁的红外辐射特性模拟。实验结果表明提出方法与现有桥梁红外成像仿真结果具有一致性,符合典型桥梁的红外热辐射规律。 相似文献
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具有优异热敏性能的氧化钒薄膜材料是红外测辐射热计的首选热敏电阻材料,合适的薄膜电阻及高温度电阻系数的氧化钒薄膜的制备是实现高探测率红外测辐射热计的保证.利用新型对靶反应磁控溅射工艺制备了具有纳米颗粒的氧化钒薄膜材料,确定了最佳工艺参数.对其组成、结构和性能进行了分析,原子力显微镜AFM形貌分析表明薄膜具有均匀致密的表面,X射线光电子能谱分析XPS确定了其组成成分主要为V2O5,VO2和少量的V2O3.在常用作微测辐射热计结构层材料的氮化硅基底上,该薄膜材料在室温附近具有合适的薄膜电阻(大约为每方14kΩ)以及高的温度电阻系数(-3.17%/℃),有望适用于非致冷红外测辐射热计探测器. 相似文献
15.
以魔芋葡甘聚糖(KGM)为对象,红外辐照时间、辐照温度、KGM含水量及分子量为考察因子,单因素探讨了红外辐照对KGM品质的影响,同时运用静态激光光散射、扫描电镜、红外光谱及X射线衍射研究了红外辐照对KGM分子结构的影响。结果显示,KGM溶胶黏度下降率与分子量呈线性正相关,溶胶黏度随红外辐照温度升高和时间延长逐渐降低,辐照温度影响尤为显著;结构表征表明73℃的红外光照射能显著降低KGM分子量及结晶度,破坏其部分有序结构,主要为分子链氧化断链所致。 相似文献
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沥青路面是我国公路的发展趋势,沥青路面维护机械也因此成了我国公路发展战略的重点。沥青路面就地热再生机组的加热部分是再生机组核心,加热程度控制得好坏直接影响了再生的质量。作者利用自行设计的燃气红外线路面加热小车进行大量实验得到丰富的数据,以可编程控制器 PLC 为控制核心开发各种加热模式的控制程序,并采用触摸屏技术使操作界面更友好。本文对加热装置和控制系统的原理及实物作了较详细介绍。 相似文献
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大部分军事目标在白天的温度高于背景,而在晚上温度却又低于背景。如何影响目标背景的温度是红外伪装的研究内容。分析了电热膜在红外伪装技术中的应用。为此分析和制备了多种电热膜材料样品,目的在于研究利用电热膜材料形成灰度可控的热图的可行性。首先测量了电热膜的热特性,包括膜表面温度与膜电阻及加热功率的关系。在此基础上,分析了基于功率控制所能实现的电热膜温度控制精度,以及基于膜电阻分布控制所能实现的膜内温度分布的空间尺度。结果表明,电热膜材料能够实现的热图的空间分辨率和温度分辨率能够满足红外伪装的要求。为进一步证实电热膜的伪装应用能力,依据特定的热图灰度等级分布情况,设计了具有特定电阻分布的电热膜样品,对这些样品进行的控温实验表明,特定电阻分布的电热膜可以很方便地形成特定的热图。这一结果明确说明了电热膜用于示假伪装的可行性。 相似文献