后向散射式激光雷达能见度探测研究

根据大气后向散射原理,设计了一台激光雷达能见度仪.在详细介绍系统结构的基础上,阐述了回波信号的数据校准方法,通过采用一种新的基于Fernald方法的迭代算法反演消光系数,获得了较高的能见度测量精度.与美国Belford能见度仪的外场对比实验表明,该激光雷达能见度仪相对测量误差在20%以内.     

便携式激光雷达能见度仪的研制

介绍了正在研制的用于较低能见度测量的便携式激光雷达能见度仪,给出了用能见度仪测量斜程能见度的测量原理,并分析了大气气溶胶消光后向散射比对能见度测量的影响。详细描述了便携式激光雷达能见度仪的系统结构和时序控制。便携式激光雷达能见度仪具有体积小,结构紧凑的特点,可用于机场等地斜程能见度的准确测量。     

基于光散射技术的两种能见度探测方法的比较分析

为了提高大气能见度的仪器探测水平,并验证自行研制的车载式拉曼激光雷达探测大气水平能见度的可靠性,使用1种基于可见光波段的前向散射能见度仪,与基于后向散射原理的拉曼激光雷达进行了联合试验,对两者测量结果,进行了分析和讨论,结果表明这两种探测手段具有较高的相关性.同时,通过对前向散射原理的探讨,为能见度仪的国产化提供了参考,也检验了国内首台车载式拉曼激光雷达在测量能见度方面的可靠性,扩展了它的应用领域.     

微脉冲激光雷达测量大气水平能见度

为了改进乃至革新大气能见度的探测技术,探索新型、快速、准确测量大气能见度的方法,采用自行研制的能见度微脉冲激光雷达,进行了水平大气能见度测量实验,并同已经商品化的能见度仪NQ-1进行了同步对比测量。实验结果表明,在水平能见度较差时,微脉冲激光雷达和能见度仪具有很高的相关性,相关系数达到了0.88;在水平能见度较好的时候,相关系数保持在0.73以上。说明能见度微脉冲激光雷达系统可以应用于大气能见度的探测。     

新型微脉冲激光雷达测量大气水平能见度

重点设计了微脉冲激光雷达(MPL)系统的后继光学单元,是一种新型的设计。使用收发一体Y型光纤束改变传统的激光雷达后继光学结构,实现系统的收发同轴设计。分析了新型微脉冲激光雷达在合肥地区实验观测结果,利用分段斜率法反演气溶胶水平消光系数,获得了大气能见度及变化特征,具有明显的日变化特征,并与HW-N1型前向散射式能见度仪测量结果进行了对比,二者相关系数达到0.81。此外,理论误差分析结果也表明当能见度在10km以下时MPL的测量误差小于20%。说明了该MPL系统能够实现对大气水平能见度的有效测量。     

半导体激光雷达的斜程能见度测量方法

针对雾天或多云天气等不均匀大气中斜程能见度难以测量的问题,提出了利用905 nm半导体激光雷达探测大气斜程及水平能见度的方法,能够探测50～2 000 m能见度范围.介绍了半导体激光雷达的系统结构,利用激光雷达测量大气能见度的原理,探测大气斜程平均能见度值.详细阐述了一种稳定的通过大气消光系数反演能见度的迭代算法,可实现迭代边界值最大距离的自动化选取,提高了迭代结果的可靠性.通过模拟计算,对该迭代方法的精度进行了评估.结果显示:50、200、800、2 000 m的能见度,迭代精度分别为33%,2%,0.1%,0.3%,由于采样点少导致极低能见度的迭代精度较低.     

基于ARM和GPRS的数据采集传输仪系统设计

文章设计了一种以ARM单片机为核心、采用GPRS作为无线传输方式的数据采集传输仪,此设备通过串口与传感器进行通信实现采集数据,然后通过GPRS模块把传感器数据发送到控制中心.文章首先介绍了ARM处理器的优点和GPRS无线传输的特点,然后重点介绍了数据采集传输仪的硬件系统,并对设计重点做了详细分析,最后对此数据采集仪的技术优势和潜在应用做了分析和展望.     

数字摄像能见度系统及其比对实验

传统的光学能见度仪分别存在各自的观测缺陷。数字摄像能见度观测系统是采用先进的数字摄像技术,完全仿照人眼观测能见度的原理,根据能见度的定义研制的新型能见度自动观测仪。本文重点介绍了它的基本原理、系统组成、硬件结构以及软件流程。最后给出了数字能见度仪与传统光学能见度仪及人工观测的比对结果。结果显示三者具有相同的变化趋势,但存在一定的观测差异。在降雨等复杂天气条件下,会有较大差异。     

含有突变信号的激光雷达能见度反演

激光雷达进行大气能见度探测时,当探测路径上存在云、雾、烟尘或硬目标时,大气消光系数会在局部发生显著变化,表现为激光雷达回波信号在原有衰减趋势上出现突变。受此影响,直接使用现有算法将导致能见度反演精度低或错误反演。为此提出一种将突变点定位、消光系数边界值确定、消光系数迭代反演相结合的能见度反演算法。首先查找、定位突变信号所在位置;然后剔除突变点,利用斜率法得到消光系数边界值;最后基于Fernald法,以迭代方式反演大气消光系数及能见度。对两种典型大气消光模式的仿真实验表明,该算法提高了能见度反演精度,能够获得更为准确的全局能见度。利用自行研制的激光雷达能见度仪实测回波数据也验证了该算法的有效性。     

基于激光雷达的水平能见度自动反演算法

激光雷达测量能见度是激光雷达的一个重要应用,水平能见度的反演在线性区的选取上存在的不确定因素制约了激光雷达的应用.本文根据激光雷达水平测量数据的特点,提出了一种迭代扩展算法确定水平测量数据的线性区,并进而反演水平能见度.该算法可以确定线性区的最大范围,并将非线性区排除出去.经实验验证表明,该算法能可靠地自动反演水平能见度.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.