微小区域热场的测试与分析

本文用显微热成像系统测量微小区域的表面温度和用数值模拟方法分析微小区域内的温度分布，对被测表面进行了发射率标定和环境辐射修正，三维稳态数值模拟着重考虑了界面接触热阻的处理。文中用以上手段分析了场效应功率器件的热可靠性。     

基于后焦面成像的液体折射率测量实验

利用磁控溅射方法在玻璃衬底上沉积一层金膜作为光学薄膜基底,在金膜上滴涂不同浓度的待测氯化钠溶液.利用光线与金属和溶液界面的表面等离子体的耦合,通过白光后焦面上暗环的相对位置,结合表面等离子体的相关理论,得到不同浓度溶液的折射率,并且分析了基于后焦面成像测量液体折射率方法的误差来源,提出了提高测量精度的办法.该实验结合了高精度的微纳加工技术以及后焦面成像过程,提出了一种新的液体折射率测量方法,在物质分析以及传感等方面有重要应用.     

红外图像伪彩色编码和处理

利用红外热成像系统可将物体的热分布转化为可视图像，并在监视器上以灰度级或伪彩色显示出来，从而得到被测目标的温度分布场。根据热成像测温原理以及红外图像的特点，在对室温热成像系统研究的基础上，对红外图像伪彩色编码进行了研究，提出一种新的伪彩色编码方法，即自动阈值法。利用自动阈值法可以在室温环境下，对目标的温度及其分布进行测量。在TMS320C6202和FPGA室温热成像系统中对提出的方法进行了验证。实验结果表明，该方法可使红外图像层次分明，容易分辨出不同的温度区域。     

光成像技术用于地铁电阻式制动器热变形的测量

由于瞬间负载大电流产生电热冲击,使得地铁使用的制动电阻器内部电阻片在热力耦合作用下过度变形。为消除接触式传感器本身对温度场和位移场的干扰,对温度和变形均采用了非接触式测量。在温度的测量中,采用了红外线遥感测温仪;在变形的测量中,应用了以数字光栅投影和Gray-code编码法为基础的结构光三维成像技术,对13个不同温度点进行了电阻片的热变形测量。通过系统标定和误差控制,使得变形测量系统的误差在0.1mm以内。非接触式测量是热应力实验研究的发展方向,而光学成像技术在热变形检测中的应用,为热应力的实验研究开辟了新的途径。     

基于成像法的玻璃厚度测量

光学成像是生活中常见的物理现象,同时也是中学物理教学中的重要内容。本文对基于成像法的玻璃厚度测量进行了研究。基于光线理论给出了经玻璃上下表面反射光的成像光斑间距与玻璃厚度之间的数学关系,设计了一套简易的实验系统,提出了一种基于“斜率逼近法”的比例系数“k”的计算方法。该玻璃测厚教学实验装置具有原理简单和成本低等优势,涉及光学成像,以及简单的图像和数据处理等内容,适合高中的教学及实验,能够激发学生对物理的兴趣,同时培养学生的逻辑分析能力和实践动手能力。     

短周期实验台涡轮机匣换热实时测量初探

本文简单介绍了采用铂膜单膜热流计和高速动态采集系统进行实时表面温度和热流率测量的原理和系统,并利用中国科学院工程热物理研究所的暂冲式短周期涡轮实验台进行了涡轮机匣换热的实时测量.测量所得的机匣表面实时温度与热流率呈现良好的周期性,并与涡轮转速相对应的高压动叶叶片通过频率相吻合.机匣表面实时温度的波动幅值极小,不超过0.4℃,而实时热流率的波动幅值达到几万瓦每平方米的量级.     

三波段光学成像系统设计及鬼像分析

为了对目标的多波段辐射特性进行测量,设计了一套300~1 000nm三波段光学成像系统.该系统共用同一入射窗口,采用两个直角棱镜进行分光,每个波段使用独立的光学成像镜头,能同时得到目标的紫外、可见光和近红外图像.利用LightTools软件对此系统的鬼像进行模拟分析,发现棱镜表面和窗口玻璃之间的光束多次反射之后,经过光学成像镜头聚焦到探测器靶面上,形成了目标的多重鬼像,大大降低了图像的对比度.实验结果表明:采用本文所述方案,三波段成像系统能达到较好的像质;将窗口玻璃和第一个棱镜的角度控制在7″之内可以消除鬼像,对使用棱镜作为分光元件的多波段光学成像系统的设计和研制具有一定的参考意义.     

轴对称悬滴法液体表面张力实验系统

研制了悬滴法液体表面张力测量系统,该系统包括图像采集系统、耐高压实验本体和温度控制系统等.悬滴图像信息由高分辨率的CMOS相机采集,并利用Canny算法进行边缘检测,进而提取悬滴边界并进行坐标变换,以获取悬滴的轮廓坐标,采用坐标轮换法与Newton法结合实现悬滴边界的全轮廓拟合计算.实验系统的温度范围和温度波动度分别为:20~180℃,±0.01℃;压力范围为:0~20MPa.为了检验系统的可靠性和精确性,测量了正庚烷在温度范围为293.15~373.15K的表面张力.通过不确定度分析,测量流体表/界面张力的相对不确定度为0.22%.     

硫系玻璃在现代红外热成像系统中的应用

介绍了硫系红外玻璃的组成成分,分析了其独特的优势,建立了红外热成像系统中各个参数和温度之间关系的数学模型。基于硫系玻璃折射率温度系数小、成本低的优点,将硫系玻璃应用于红外热成像探测系统,并给出了一种折射式的中波红外热成像消热差探测系统实例,评价结果表明,该系统在低温-40 ℃、常温20 ℃、高温60 ℃都取得了良好的成像质量,适用于像元数为320 pixel×256 pixel,像元尺寸为30 μm×30 μm的中波红外凝视型焦平面阵列探测器。     

自聚焦透镜列阵的色差测量

本文分析了色差的产生和表示，计算和测量了锂玻璃自聚焦透镜成像系统中的轴向色差与横向色差，讨论了色差对自聚焦透镜列阵成像的影响。     

红外热波成像法测量固体材料热扩散率

本文通过采用连续激光调制对试样周期加热产生稳定的温度波动和红外扫描动态测温的红外热波成像法获得温度波动的相位和幅值分布，测量固体材料热扩散率。介绍了红外热波成像法的测量原理和实验系统，推导了热扩散率测量的相位法、幅值法和相位－幅值复合法。对不锈钢和纯镍试样的热扩散率进行了测试。测量结果表明，该方法具有较高的精度。     

Pd-Ni-P大块金属玻璃的形成及其转变动力学

本文报道了Pd-Ni-P合金的过冷实验结果,研究了冷却速度对合金过冷行为的影响。通过将样品包裹在B₂O₃中从而减少样品的表面非均匀生核,使得样品在极低的冷却速度下形成大块金属玻璃。在玻璃转变温度(T_g=590K)处,冷却速度低达1K/s。利用经典的均匀生核与非均匀生核理论,计算了Pd₄₀Ni₄₀P₂₀合金的温度、时间转变曲线(即TTT图)。确定了合金的临界冷却速度。对结果进行了详细的讨论。 关键词：     

Thermophysical properties of Ni-5%Sn alloy melt

The surface tension and specific heat of Ni-5%Sn alloy melt were measured by the oscillating drop method and the drop calorimetric method using electromagnetic levitation, respectively. The temperature coefficient of surface tension is 6.43×10⁻⁴ N·m⁻¹K⁻¹ within the temperature regime of 1464–1931 K. The enthalpy change was measured in the temperature range from 1461 to 1986 K, and the average specific heat was obtained as 43.03 J·mol⁻¹K⁻¹. Some other thermophysical properties, such as viscosity, solute diffusion coefficient, density, thermal diffusivity and thermal conductivity of this alloy melt, were derived based on the experimentally measured surface tension and specific heat. Using these thermophysical parameters, the relation between solute trapping and undercooling in rapidly solidified α-Ni was calculated, and the theoretical prediction shows a good agreement with experimental data.     

新型GeSe2-In2Se3-AgI玻璃性能研究

采用传统熔融-淬冷法制备了一系列新型(100-x)(4GeSe2-In2Se3)-xAgI(x=20,30,40mol%)硫系玻璃样品.利用X射线衍射分析、差热分析、可见-近红外吸收光谱、红外透过光谱、喇曼分析等技术手段研究了该玻璃系统的组成、结构、热稳定性和光学特性等.利用Tauc方程计算出了样品的间接带隙;测试了部分样品在不同升温速率下的差示扫描量热曲线,并采用Kissinger法计算了玻璃样品的析晶活化能.X射线衍射数据表明,该玻璃体系在较宽的组分范围内有良好的非晶特性,成玻范围较宽;差热分析和析晶动力学研究表明,玻璃样品70(4GeSe2-In2Se3)-30AgI具有较好的热稳定性(ΔT=114℃)和较高的活化能(Ea=320.4kJ/mol).随着AgI含量的增加,玻璃的短波吸收限蓝移,并且光学带隙有增大的趋势.此外,红外透过光谱分析表明该玻璃体系具有良好的红外透过性能,其红外截止波长不会随着AgI含量的增加而发生明显变化,皆为16μm左右.     

Infrared thermography and its application in the NDT of sandwich structures

Thermographic nondestructive testing (NDT) based on the thermal resistance effect of defects is developed for the inspection of delaminated and sandwiched defects embedded in composite structures. The resolution is examined for artificial delaminated defects in carbon-fiber honeycomb structures using conventional infrared radiation heating. The experimental results have demonstrated that radiation heating is effective for revealing defects in the composite structures.An experimental and computational hybrid system is developed for detecting defects in various composite structures. The system consists of an infrared thermal video system which measures the surface temperature distribution of the structure, a computer with a PIP-1024B image board which performs image processing of thermograms, and a HP ink jet XL printer. It is found that this system is readily applicable to the detection of defects located at the interface of the core and skin in honeycomb structures and delaminations in composite materials.     

The interface structure of nano-SiO2/PA66 composites and its influence on material's mechanical and thermal properties

The PA66-based nanocomposites containing surface-modified nano-SiO₂ were prepared by melt compounding. The interface structure formed in composite system was investigated by thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The influence of interface structure on material's mechanical and thermal properties was also studied. The results indicated that the PA66 chains were attached to the surface of modified-silica nanoparticles by chemical bonding and physical absorption mode, accompanying the formation of the composites network structure. With the addition of modified silica, the strength and stiffness of composites were all reinforced: the observed increase depended on the formation of the interface structure based on hydrogen bonding and covalent bonding. Furthermore, the differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) showed that the presence of modified silica could affect the crystallization behavior of the PA66 matrix and lead to glass transition temperature of composites a shift to higher temperature.     

X-ray reflectivity studies on glass transition of free standing polystyrene thin films

We have studied thermal expansion of free standing polystyrene thin films using X-ray reflectivity to elucidate the glass transition temperature and the thermal expansivity. We found that the glass transition temperature T_g decreased with the film thickness, depending on molecular weight. The reduction in the free standing films is much larger than in the supported films on Si substrate, suggesting that some segmental motions are activated due to free surfaces on both sides in the free standing films. We also found that the thermal expansivity in the glass and the melt decreased with the film thickness. This decrease must be attributable to chain confinement effects.     

影响陶瓷坯体烧成过程中热应力变化的因素研究

1前言陶瓷坯体在烧成过程中的温度场和热应力场，是影响制品烧成质量的主要因素。尽管三维热应力的数值分析在其他领域内已经得到一些应用，但在陶瓷烧成的热应力分析领域却还未发现，随着对产品质量的越来越关注，人们已逐渐地把目光转移到陶瓷坯体烧成过程的研究中，一方面为了探讨坯体烧成中的变形机理、探讨陶瓷材料物性参数及力学参数对坯体烧成中热应力的影响，另一方面为了寻找制品的最佳烧成曲线，摆脱长期以来受经验所制约的情况，以期以最短的时间烧制出符合质量要求的最佳产品，达到节能、高产和低能耗的目的，这些需求使得对生…     

Laser opto-acoustic study of phase transitions in metals confined by transparent dielectric

First-order phase transitions in metal induced by nanosecond laser pulse are studied here. The metal surface is irradiated through a layer of transparent dielectric??an optical glass. Such confinement considerably increases the efficiency of pressure generation at the metal surface. This technique allows to obtain near-critical states of metals??with temperatures ??10⁴ K and pressures ??10⁴ atm with table-top equipment. At the same time the glass prevents the ablation plume formation??so the surface temperature can be measured using thermal radiation data. An experimental setup for simultaneous measurements of pressure, temperature and reflectivity was assembled based on the elaborated method of experimental research. The processes of melting of lead and boiling of mercury were studied. The onset of the phase transition process led to a considerable tightening of the pressure pulse. A substantial drop of surface reflectivity due to increase of temperature and decrease of density was observed.