瑞利散射激光雷达强光感生噪声修正的新方法及大气温度探测

借助一套全新的地面高精度光电探测器强光感生噪声检测平台,建立了强光感生噪声精细结构扣除模型,同多通道信号接收技术相结合,改进了一台用于中高层大气温度探测的子午工程双波长三通道瑞利散射激光雷达数据的处理方法。处理后数据反演的大气温度廓线与TIMED卫星结果相比较,得到了很好的吻合。在35~85km高度范围内二者反映了较一致的温度分布特征,30~55km温度误差小于±5K,55~75km温度误差小于±10K。     

激光雷达探测平流层中上部大气密度和温度

用L625 355 nm和532 nm双通道瑞利(Rayleigh)散射激光雷达,分别观测合肥(31.9°N/117.17°E)地区30～43 km高度范围内的大气密度和温度分布.这些结果与NOAA/NMC和NASA/HALOE相邻地点的密度和温度表现了较好的一致性.一般情况下,在34～43 km高度范围内激光雷达获得的大气密度与NOAA/NMC和NASA/HALOE密度的偏差大约为10%,温度差别小于2 K,而34 km以下温度偏差稍大.     

平流层大气温度探测通道选择数值试验

通过等效通道选择原理分析，认为通过构建等效通道，可使其权重函数峰值高度高于目前美国ＤＯＡＡ气象卫星ＨＩＲＳ／２第一通道的峰值高度，通过大量的模拟计算试验，证实了这一原理实现的可能性，进一步利用１５μｍＣＯ２吸收带的７个温度探测通道的所选择的等效通道一起反２大气温度垂直分布，结果表明增加一个等效通道对温度廓线反演有一定改善，特别是对平流层（５０－２ｈＰａ）温度反演，平均每层精度提高的０．２７Ｋ。     

合肥上空中层大气密度和温度的激光雷达探测

为研究中层大气分布情况,采用自行研制的532 nm瑞利（Rayleigh）散射激光雷达,对合肥地区（31.90 N,117.170 E）25~40 km高度范围内的大气密度和温度廓线分布进行观测。将瑞利散射激光雷达所测结果与NRLMSISE-00大气模型数据进行对比,以验证瑞利散射激光雷达性能及数据处理方法的可靠性。通过数据对比得出,在25~40 km高度范围内,瑞利散射激光雷达获得的大气密度值与NRLMSISE-00大气模型密度值的比值为0.99~1.03;瑞利散射激光雷达所测温度值与NRLMSISE-00大气模型数据的温度偏差均值约为2.8 K,其中38 km以下两者温度偏差约为1.6 K。数据对比说明,瑞利散射激光雷达观测值与NRLMSISE-00大气模型数据具有较一致的密度分布特征和温度分布特征,瑞利散射激光雷达的观测结果能够较真实地反映合肥上空25~40 km高度范围内的大气密度和温度分布。     

瑞利-拉曼散射激光雷达探测大气温度分布

介绍一台用于夜晚探测大气温度分布的L625瑞利-拉曼(Rayleigh-Raman)散射激光雷达。采用Nd：YAG激光器三倍频输出355nm作为发射激光，利用弱光子计数技术检测大气中分子的瑞利散射和N2分子振动拉曼散射回波，分析得到了平流层和对流层中上部大气温度的垂直分布廓线。其观测结果分别与HALOE／UARS卫星和无线电气象探空仪结果进行了对比分析。其中，激光雷达观测的平流层温度与HALOE卫星的结果对比表明，它们在高度25～65km内显示出较好的一致性，20个夜晚的平均温度差别基本上小于2K。激光雷达与无线电气象探空仪探测的对流层温度在高度为5～18km内反映了较为一致的分布趋势，15个夜晚的平均温度差别在6～16．5km高度内小于3K。这些结果表明，L625瑞利-拉曼散射激光雷达观测数据可靠，可用于大气温度分布的常规观测和分析研究。     

瑞利激光雷达探测大气温度算法分析

介绍了瑞利激光雷达的基本结构,描述了使用瑞利散射激光雷达探测平流层和中间层低部大气温度的数据处理方法,构建同时包含标准大气模式温度信息和实际探测背景噪声的模拟数据,对此模拟数据进行背景扣除、平滑去噪、参考点选取等计算分析,探讨提高温度反演精度的实用算法。并应用此数据处理方法对瑞利激光雷达的实际测量数据进行了计算处理,将计算结果与模式CIRA86、HALOE卫星数据进行对比分析,反演高度30～45km时误差1～3K,45～65km误差大约在2～5K,65～70km误差＜10K。     

瑞利激光雷达探测大气温度算法分析

介绍了瑞利激光雷达的基本结构,描述了使用瑞利散射激光雷达探测平流层和中间层低部大气温度的数据处理方法,构建同时包含标准大气模式温度信息和实际探测背景噪声的模拟数据,对此模拟数据进行背景扣除、平滑去噪、参考点选取等计算分析,探讨提高温度反演精度的实用算法。并应用此数据处理方法对瑞利激光雷达的实际测量数据进行了计算处理,将计算结果与模式CIRJA86、HALOE卫星数据进行对比分析,反演高度30～45km时误差1—3K,45～65km误差大约在2—5K,65—70km误差〈10K。     

用于探测大气臭氧的准分子激光雷达系统

测量臭氧在大气中垂直分布的最有前途的方法之一是最近在紫外光谱区用差分吸收法的雷达探测.这种雷达的工作原理在于:记录在大气中散射的两个接近波长的光信号,其中之一在所研究的气体中强吸收,第二个波长是参考波.关于在紫外光谱区的雷达系统用于测量对流层和平流层臭氧的浓度已有一些报导.     

大气探测激光雷达技术综述

大气探测激光雷达具有可提供高时空分辨率、高探测精度和连续廓线数据的优势,已经成为大气探测强有力的工具。按照激光雷达探测技术分类,有米散射激光雷达、偏振激光雷达、拉曼激光雷达、差分吸收激光雷达、高光谱分辨率激光雷达、瑞利散射激光雷达、共振荧光激光雷达和多普勒激光雷达等,分别介绍了各类激光雷达探测的基本原理、发展历史及优缺点,以及其在探测大气气溶胶和云、水汽、温度、风、痕量气体、温室气体和污染气体等方面的应用。最后进行总结,并对激光雷达技术发展趋势进行了展望。     

Bondability analysis of bond pads by thermoelectric temperature measurements

To reduce cost and enhance reliability for microelectronics applications, a complete understanding of the thermosonic bonding process is required. In particular, the question of whether melting, diffusion, or significant heating occurs along the interface during friction has often been raised. We present results obtained with a new device based on thermoelectric temperature measurements to determine the temperature at the bond interface. In addition to the temperature information, the data characterizes the bonding process in real time on a micrometer scale. The basic principle of the developed apparatus is temperature measurement by an Au-Ni thermocouple fixed within the inside chamfer of a bonding capillary. Different bond substrates with high and low bond contact quality have been investigated. The thermoelectric temperature measurements very precisely determines the bonding behavior of the bond pads. A few nanometers surface contamination on a bond pad significantly reduces the temperature rise at the bond interface and therefore impairs bondability of the substrate. These results demonstrate the sensitivity and accuracy of the measurement principle. The apparatus is a powerful tool to measure the tribology of the bond system and to characterize the bondability of different bond pads.     

Wafer emissivity independent temperature measurements

A study on the techniques to yield wafer emissivity independent temperature measurements in rapid thermal processing has been presented. This study focuses on the Steag-AST Electronik approach to enhance wafer emissivity by using the Hotliner*. The Hotliner comprises of a heavily doped p-Si substrate sandwiched with Si₃N₄/SiO₂ from both sides. Experimental measurements on the optical properties of the Hotliner using a spectral emissometer operating in the wavelength range of 1–20 μm are presented here. Results of the simulation of the experimental data using the MIT/SEMATECH Multi-Rad model are discussed. Hotliner is a trademark of Steag-AST Electronik, patent pending.     

Internal temperature distribution measurements in high powersemiconductor lasers

A novel technique to measure internal temperature distributions within high power semiconductor lasers with substrates transparent to the laser radiation is presented. The temperature resolution is better than 1°C with a spatial resolution of 1-2 μm. The results show highly non-uniform transverse temperature distributions and significant heating close to the facet at high output powers     

极区中层夏季回波与偶发E层关系的初步研究

极区中层夏季回波（PMSE,Polar Mesosphere Summer Echoes）是发生在当地夏季极区中层顶附近的一种异常强大的雷达回波。利用电离层测高仪观测到的频高图来确定极区中层夏季回波偶发E层（PMSE-Es,Polar Mesosphere Summer Echoes-Sporadic E） PMSE-Es现象,进而研究南北半球PMSE现象。利用南极中山站数据结合新的统计方法给出了1999至2003年PMSE-Es出现率季节性变化,与北极对应年的PMSE出现率对比发现：它们的结果趋于一致,特别是在2002年,它们的出现率均明显偏低。这表明PMSE-Es与PMSE现象可能具有一定的相关性,将来可以利用电离层测高仪观测PMSE,监测全球变暖的环境问题。     

Thermoreflectance temperature measurements for optically emitting devices

This work examines the difficulties associated with using optical techniques to measure temperature when the device itself emits a significant level of light over a wide spectrum, making it a challenge to separate the useful measurement signature from the device light emission. The specific situation considered here is that of using a thermoreflectance (TR) thermography approach to characterize the thermal behavior of semiconductor laser devices. A lowpass filter was placed in the optical path to minimize the primary laser irradiation on the TR imaging and then the TR response of the region of interest was determined over a wide range of visible light wavelengths to locate the maximum response. TR measurements performed at the optimal light wavelength successfully provided a submicron-resolution temperature map of the active area of sample lasers.     

Q band interferometer for high temperature measurements

A Q band interferometer for determining the complex permittivity of solids and liquids between 20°C and 1300°C has been developed. The Roberts and Von Hippel standing-wave method was used. The technique involves the utilization of a computer-assisted digital voltmeter for data acquisition and treatment. Results for a 67SiO₂?33Na₂O within the temperature range 20–400°C and in the liqid state (950°C) are presented.     

Applications of temperature phase measurements to IC testing

This work analyses the applicability of silicon surface temperature phase measurements as a test observable when a device acting as a heat source dissipates a modulated power function. Specifically, this paper considers two different functions: the phase shift of the temperature waveform as a function of frequency and distance, and the slope of the temperature phase shift versus distance as a function of frequency. Different cases are analyzed in order to show the potential of both functions, including experimental results obtained from a specific integrated circuit (IC). The conclusions will show that samples of the phase function can be used to locate devices acting as heat sources, and that the slope function can be used to extract information regarding the heat flow path in the IC, and, therefore, regarding the structure of the IC.     

Analysis of the input noise contribution in the noise temperature measurements

In measuring the noise temperature of a cryogenic microwave low-noise amplifier (LNA), the noise from the input thermal buffer, i.e., the coaxial cable that connects the noise source to the amplifier, needs to be correctly accounted for. With the amplifier's noise temperature approaching just a few Kelvins, the postulate used in calculating the cable's noise temperature, that the cable is homogeneous and has a linear temperature profile, commands a further inspection. This letter analyzes these assumptions and clarifies the situations in which they hold. To substantiate this Kelvin-level discretion, a LNA is designed and measured.     

The recovery of polarized apparent temperature distributions of flat scenes from antenna temperature measurements

The reception theory for quasi-monochromatic partially polarized emissions is employed to describe the antenna temperature when observing a flat scene from within or above an absorbing/ emitting atmosphere. When the polarization aspects of the antenna and scene are carefully observed, the resulting integral expression for the antenna temperature differs significantly from that reported for polarization invariant temperature distributions. It is observed that the antenna couples to both emitted surface polarizations, and the phase character of the antenna introduces a term involving the product of the polarized and cross-polarized antenna patterns. A matrix approximation of the integral expression is suggested and developed as a means for inverting polarized antenna temperature observations for the underlying partially polarized apparent temperature distributions. The resulting matrix formulation is interpreted and special cases are treated. By means of sample cases, the cross-coupling effect between the antenna and the emitted field polarization vectors is illustrated. When the polarization aspects of the radiometer and the scene are ignored, inversions for the apparent temperature are shown to suffer appreciably even for a highly efficient antenna. The sensitivity of the matrix inversion technique to errors in the measurement vector is also examined.