Calibration and analysis of spatially resolved x-ray absorption spectra from a nonuniform plasma

We report here the calibration and analysis techniques used to obtain spatially resolved density and temperature measurements of a pair of imploding aluminum wires from x-ray absorption spectra. A step wedge is used to measure backlighter fluence at the film, allowing transmission through the sample to be measured with an accuracy of ±14% or better. A genetic algorithm is used to search the allowed plasma parameter space and fit synthetic spectra with 20?μm spatial resolution to the measured spectra, taking into account that the object plasma nonuniformity must be physically reasonable. The inferred plasma conditions must be allowed to vary along the absorption path in order to obtain a fit to the spectral data. The temperature is estimated to be accurate to within ±25% and the density to within a factor of two. This information is used to construct two-dimensional maps of the density and temperature of the object plasma.     

引导信息处理中的数据融合

本文从引导系统存在多数据源的实际情况出发,对数据的融合处理方法进行了研究,并对卡尔漫滤波算法进行了一定改进,提出一种基于数据融合,充分利用现有引导数据源实现对靶场光学测试设备平稳跟踪引导的算法.     

自动气象站数据处理系统设计

针对在气象业务中对地面观测资料的统计和应用问题,利用Visual Basic和SQL Server 2000开发了自动气象站数据处理系统。系统可从自动气象站的观测资料中按照固定时间自动地提取数据,并把数据录入数据库。用户可利用数据库查询实时或者历史的相关气象数据,并实现气温、露点温度、相对湿度、气压、风向、风速、降水量等气象要素的统计功能。     

数据仓库的综合处理模型研究

数据仓库模式的建立、数据的栽入、数据的分析和呈现是数据仓库设计的重要步骤。本文对数据仓库的数据模型、处理流篓堂．体系结构进行了深入的研究，在现有的技术和需求的基础上，总结出了一个数据仓库的综合处理模型，重点讨论了数据综合处理模型的详细结构和处理任务。该模型的提出有利于提高数据仓库的设计效率。     

盘形凸轮轮廓曲线检测中的数据处理

介绍了在数控凸轮磨床工作台上对平面凸轮轮廓线进行检测的方法,这里主要介绍盘形凸轮轮廓曲线检测中数据处理的方法,并详细介绍了曲线拟合方法。     

基于模糊模式识别的爆炸物THz光谱识别

运用太赫兹(THz)光谱特性对爆炸物进行检测和识别,是现代检测技术研究的一个热点.在对多种单质炸药和混合炸药及几种可能与它们混淆的物质的太赫兹特征吸收光谱进行研究的基础上,提取它们在0.2～2.2THz频率范围内4个相对较强的特征吸收峰作为分类识别的特征参数,用模糊模式识别方法对它们的太赫兹特征吸收谱进行了分类和识别.首先,用基于模糊等价关系的模糊聚类分析方法对这几种物质的太赫兹特征吸收谱进行聚类训练,获得样品分类并形成标准太赫兹吸收光谱模型库;然后,选用与训练样本主体成分相同的2种物品作为待识别对象,采用基于择近原则的模糊模式识别方法进行了成功识别.研究结果表明,基于模糊聚类分析的模糊模式识别方法对太赫兹吸收谱具有较强的相似特征聚类功能和较高的识别率,为太赫兹光谱技术用于爆炸物的检测和识别提供了一种有效的方法.     

数据压缩编码器中Z扫描电路的设计与仿真

对数据压缩编码器中的z扫描电路的功能和在整个编码器中的任务进行了分析,在此基础上,设计出了Z扫描电路的总体结构,并进行了仿真,最后根据输出波形验证了设计的正确性.     

Two-photon fluorescence absorption and emission spectra of dyes relevant for cell imaging

Two‐photon absorption and emission spectra for fluorophores relevant in cell imaging were measured using a 45 fs Ti:sapphire laser, a continuously tuneable optical parametric amplifier for the excitation range 580–1150 nm and an optical multichannel analyser. The measurements included DNA stains, fluorescent dyes coupled to antibodies as well as organelle trackers, e.g. Alexa and Bodipy dyes, Cy2, Cy3, DAPI, Hoechst 33342, propidium iodide, FITC and rhodamine. In accordance with the two‐photon excitation theory, the majority of the investigated fluorochromes did not reveal significant discrepancies between the two‐photon and the one‐photon emission spectra. However, a blue‐shift of the absorption maxima ranging from a few nanometres up to considerably differing courses of the spectrum was found for most fluorochromes. The potential of non‐linear laser scanning fluorescence microscopy is demonstrated here by visualizing multiple intracellular structures in living cells. Combined with 3D reconstruction techniques, this approach gives a deeper insight into the spatial relationships of subcellular organelles.     

航天测量船船体变形的数据处理

为了克服船体变形对航天测量船船载设备外测数据的影响,需对船载设备外测数据进行船体变形修正,为此建立了船体变形修正数学模型.从航天测量船船体变形测量系统的基本构成、测量原理和测量元素入手,建立变形测量坐标系,讨论变形测量角与欧拉角的关系,详细推导了船体变形数据处理计算公式,给出了变形数据处理的数学模型.工程应用结果表明:船体变形对飞行器初轨半长轴a的影响比较大,对于近地近圆轨道,影响值是几百米的量级,最大达到800～900 m,而对于大椭圆轨道,影响值则达20 km,经船体变形修正后可以消除这项影响.建立的变形修正数学模型反映了船体变形的客观规律,能有效消除船体变形对船载设备外测数据的影响,提高测量船外测数据处理的精度.     

A simple method for obtaining and analysing the absorption spectra of microscopic specimens

A method is described for obtaining and analysing the absorption spectra of microscopic specimens, using readily available laboratory equipment. Spectra obtained from the primary image with a hand spectroscope are recorded photographically and the negative images subsequently analysed, in terms of optical density relative to a standard spectrum, using a gel scanner densitometer and chart recorder. The system has been used to recognize and characterize the haemoglobin of a symbiotic flatworm, absorption peaks being resolved to within 5.0 nm. Separation of the recording and analytical stages confers flexibility since records can be made, if desired, in the field or by co-workers elsewhere and analysed later in the base laboratory.     

基于原子吸收光谱的环境重金属离子检测技术进展

原子吸收光谱法是分析环境水样中重金属含量的有效方法之一。在测定时往往需要对样品进行前处理,然后再进行测定。本文介绍了近年来一些分离富集技术在原子吸收光谱分析环境水样中重金属离子时的应用,并比较了火焰原子化、石墨炉原子化及低温原子化方法测定水中重金属元素的优缺点,对今后原子吸收光谱法在重金属离子检测发展进行了展望。     

Data taking from multiwire chambers and hodoscopes at IHEP physical setups

The LE-73 and LE-78 modules of MISS system designed for readout and recording of signals from multiwire chambers and hodoscopes are described. The use of an Altera FPGA provides a means for producing different modifications of the modules and adapting their operation to specific requirements of experimental setups. Owing to the availability of a high-speed internal memory, it is possible to design time-to-digital converters with a “common stop” and a 5-ns step and to store data in an internal FIFO memory.     

紫外可见光谱法和主成分分析对蓝色圆珠笔油墨分类的研究

采用薄层色谱法和紫外可见光谱法分析34支蓝色圆珠笔油墨。截取400～700nm之间的紫外可见光谱数据进行主成分分析。主成分分析表明主成分1、2和3的累积贡献率已达96.5%,以主成分1、2对所有样品的得分值作图,对不同品牌的圆珠笔有很好的聚类作用。将主成分分析的分类结果同薄层色谱法的分类结果相比较,结果表明,采用主成分分析技术可以达到对蓝色圆珠笔油墨字迹的良好识别。     

Development of a time-resolved soft x-ray spectrometer for laser produced plasma experiments

A 2400 lines/mm variable-spaced grating spectrometer has been used to measure soft x-ray emission (8-22 A?) from laser-produced plasma experiments at Lawrence Livermore National Laboratory's Compact Multipulse Terrawatt (COMET) Laser Facility. The spectrometer was coupled to a Kentech x-ray streak camera to study the temporal evolution of soft x rays emitted from the back of the Mylar and the copper foils irradiated at 10(15)?W/cm(2). The instrument demonstrated a resolving power of ～120 at 19 A? with a time resolution of 31 ps. The time-resolved copper emission spectrum was consistent with a photodiode monitoring the laser temporal pulse shape and indicated that the soft x-ray emission follows the laser heating of the target. The time and spectral resolutions of this diagnostic make it useful for studies of high temperature plasmas.     

无线传感器网络中网关处的数据获取与处理

本文首先讨论无线传感器网络中的数据获取与处理技术,并以Crossbow公司的MICAz套件为开发平台,给出数据获取和处理系统的具体实现.     

基于神经-模糊推理系统的机械设计数据处理

针对机械设计领域中所存在的大计算量、多图表问题,应用一种神经-模糊推理系统进行映射辩识,以提高计算速度和编程处理能力,消除知识的组合爆炸现象。通过对具体数据、图表的实际应用表明,应用这种方法能够很好地表达原图表数据关系。同时,相对于单纯应用人工神经网络方法,它的数据识别精度更高,速度更快,能够满足设计计算要求。     

紫外可见主成分分析法对蓝色签字笔油墨的分类研究

本文采用薄层色谱法和紫外可见光谱法分析33支蓝色签字笔油墨。截取400～700 nm之间的紫外可见光谱数据进行主成分分析。主成分(PC)分析结果表明主成分1、2和3的累积贡献率已达86.84%,以主成分1、2对所有样品的得分值作图,结果显示时不同品牌的蓝色签字笔有很好的聚类作用。将主成分分析的分类结果同薄层色谱法的分类结果相比较,结果表明,采用主成分分析技术可以达到对蓝色签字笔墨字迹的良好识别。     

高炉专家系统数据采集及处理方法的研究

针对利用传统的数据采集方法很难满足工业现场数据采集的问题,根据江苏永联钢铁集团公司进行高炉专家系统开发的经验,结合一般工业企业对于数据采集及处理的研究,改进了传统的利用OPC采集工业现场数据的方法,提出了采用IO Server中间数据采集层的数据获取方法。并针对高炉数据复杂、干扰大的特点,研究了高炉数据特性,给出了数据处理的主要方法。研究结果表明,利用此种方法采集数据具有较强的适用性和很高的稳定性,为高炉专家系统的发展提供了较为实用的参考价值。     

Elemental mapping using the Ga 3d and In 4d transitions in the epsilon2 absorption spectra derived from EELS

It is proposed that by using the valence-band states in electron energy loss spectroscopy, high-spatial resolution maps of quantitative elemental composition may be acquired with high acquisition rates. Further, it is shown that by using the epsilon(2) spectrum instead of single scattering data, the noise in the observed transitions and associated maps is significantly reduced. The epsilon(2) spectra are derived through a Kramers-Kronig transformation from electron energy loss spectra obtained in a scanning transmission electron microscope. Using transitions that occur in the epsilon(2) absorption spectrum (<40eV), quantitative elemental maps for III-V device structures have been produced. An example is provided using the Ga 3d transition to map a GaInNAs/GaAs laser structure. Weaker transitions such as In 4d have also been used to verify the Ga elemental distribution.     

Development of a low-energy and high-current pulsed neutral beam injector with a washer-gun plasma source for high-beta plasma experiments

We have developed a novel and economical neutral-beam injection system by employing a washer-gun plasma source. It provides a low-cost and maintenance-free ion beam, thus eliminating the need for the filaments and water-cooling systems employed conventionally. In our primary experiments, the washer gun produced a source plasma with an electron temperature of approximately 5 eV and an electron density of 5 × 10(17) m(-3), i.e., conditions suitable for ion-beam extraction. The dependence of the extracted beam current on the acceleration voltage is consistent with space-charge current limitation, because the observed current density is almost proportional to the 3∕2 power of the acceleration voltage below approximately 8 kV. By optimizing plasma formation, we successfully achieved beam extraction of up to 40 A at 15 kV and a pulse length in excess of 0.25 ms. Its low-voltage and high-current pulsed-beam properties enable us to apply this high-power neutral beam injection into a high-beta compact torus plasma characterized by a low magnetic field.