北京谱仪Ⅱ（BESⅡ）顶点探测器数据获取系统

北京谱仪（ＢＥＳⅡ）顶点探测器数据获取系统是北京谱仪数据获取系统的一部分，该子系统电子学采用快总线标准，本文描述了该系统的硬件结构和软件系统，软件包括快总线系统的微码软件和上层控制软件，该系统的死时间为１．５ｎｓ，对ＢＥＳⅡ系统总死时间的贡献小于０．５ｍｓ。     

Invasive species detection in Hawaiian rainforests using airborne imaging spectroscopy and LiDAR

Remote sensing of invasive species is a critical component of conservation and management efforts, but reliable methods for the detection of invaders have not been widely established. In Hawaiian forests, we recently found that invasive trees often have hyperspectral signatures unique from that of native trees, but mapping based on spectral reflectance properties alone is confounded by issues of canopy senescence and mortality, intra- and inter-canopy gaps and shadowing, and terrain variability. We deployed a new hybrid airborne system combining the Carnegie Airborne Observatory (CAO) small-footprint light detection and ranging (LiDAR) system with the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) to map the three-dimensional spectral and structural properties of Hawaiian forests. The CAO-AVIRIS systems and data were fully integrated using in-flight and post-flight fusion techniques, facilitating an analysis of forest canopy properties to determine the presence and abundance of three highly invasive tree species in Hawaiian rainforests.

The LiDAR sub-system was used to model forest canopy height and top-of-canopy surfaces; these structural data allowed for automated masking of forest gaps, intra- and inter-canopy shadows, and minimum vegetation height in the AVIRIS images. The remaining sunlit canopy spectra were analyzed using spatially-constrained spectral mixture analysis. The results of the combined LiDAR-spectroscopic analysis highlighted the location and fractional abundance of each invasive tree species throughout the rainforest sites. Field validation studies demonstrated < 6.8% and < 18.6% error rates in the detection of invasive tree species at  7 m² and  2 m² minimum canopy cover thresholds. Our results show that full integration of imaging spectroscopy and LiDAR measurements provides enormous flexibility and analytical potential for studies of terrestrial ecosystems and the species contained within them.     

一台用于环境样品分析的γ谱仪系统的性能与评论

本文介绍和评论了我所建立的环境实验室Ge(Li)γ谱仪系统的性能和应用。提出了一般环境实验室中使用一个中等体积和性能的高分辨率锗或Ge(Li)γ谱仪,加上适当的物质屏蔽就可以满足一般环境或生物样品中γ谱分析。     

The effect of anisotropic reflectance on imaging spectroscopy of snow properties

How does snow's anisotropic directional reflectance affect the mapping of snow properties from imaging spectrometer data? This sensitivity study applies two spectroscopy models to synthetic images of the spectral hemispherical-directional reflectance factor (HDRF) with prescribed snow-covered area and snow grain size. The MEMSCAG model determines both sub-pixel snow-covered area and the grain size of the fractional snow cover. The Nolin/Dozier model analyzes the ice absorption feature that spans wavelength λ≅1.03 μm to estimate snow grain radius when the pixel is fully snow-covered. Retrievals of subpixel snow-covered area with MEMSCAG are progressively more sensitive to the HDRF as grain size decreases, solar zenith angle increases, and fractional snow cover increases. The model overestimates snow cover in the forward reflectance angles by up to +20% and underestimates it in the backward reflectance angles by as much as −15%. Grain size retrievals from both MEMSCAG and Nolin/Dozier are more sensitive to anisotropy as grain size and solar zenith angle increase. MEMSCAG retrievals of grain size are insensitive to snow-covered area. The largest inferred grain sizes occur around a peak in the backward reflectance angles and the smallest generally occur at the largest view angles in the forward direction. Retrievals of albedo from MEMSCAG and Nolin/Dozier are similarly sensitive to anisotropy, with albedo errors up to 5% for a 30° solar zenith angle and up to 10% at 60°. The albedo differences between the two models are less than 0.015 for all grain sizes and solar zenith angles.     

短波段傅里叶变换光谱技术的初步研究

本文介绍了傅里叶变换光谱技术向短波段的扩展和应用, 描述了在研真空紫外傅里叶变换光谱仪原理样机的结构设计和预期性能。讨论了短波段谱仪多重传输特性, 得出对于发射光谱强谱线的测量, 其多生传输优势依然存在的结论     

有机溶剂溶解法结合电感耦合等离子体发射光谱法直接测定软胶囊剂型保健食品中的钙和铁

目的 建立电感耦合等离子体发射光谱法(inductively coupled plasma optical emission spectrometry,ICP-OES)测定软胶囊剂型保健食品中的钙和铁含量的方法。方法 软胶囊剂型保健食品经水-硝酸-二甲亚砜混合溶液溶解后,使用电感耦合等离子体发射光谱仪,直接测定其中的钙和铁含量。结果 钙元素方法的检出限为3 mg/kg,定量限为9 mg/kg,钙元素的回收率在92.2%～96.7%之间,相对标准偏差(relative standard deviations,RSDs)在3.2%～8.8%之间。铁元素方法的检出限为0.6 mg/kg,定量限为2 mg/kg,铁元素的回收率在91.8%～96.7%之间,RSDs在1.8%～11.9%之间。实际样品检测时,同时采用了本方法与GB 5009.268—2016《食品安全国家标准食品中多元素的测定》(第二法),两种方法所得结果没有明显差异。结论 本方法在前处理时,不再使用传统的微波消解等方法,操作简单、快捷、准确度高,可以用于软胶囊剂型保健食品中钙和铁的检测。     

空间外差光谱仪系统设计

围绕空间外差光谱仪系统参数设计进行了理论分析和实验研究。介绍了空间外差光谱仪系统的基本结构和原理,并针对其光学系统设计,详述了系统的主要指标:光谱分辨率极限、分辨能力、光谱范围与关键光学器件:光栅、探测器、成像系统等参数的匹配关系。给出了一个完整的系统参数设计实例,并根据光学系统参数对干涉图进行了理论仿真。以搭台的方式建立空间外差光谱仪原理试验装置,并进行了典型光谱实验验证,系统检测结果表明光谱分辨能力在591 nm达到了17 700,光谱范围为574~591 nm。实验结果与仿真结果比较还表明,系统的光谱范围、光谱分辨率等指标达到了设计要求,验证了设计方法的可行性。     

用“Stopped——Flow”分光光度计研究快速反应动力学和机理

本文介绍了Stopped--Flow分光光度计的原理、发展、仪器主要组成部分及应用范围。并研究讨论了Fe~(3 ) SCN~-(?)FeSCN~(2 )快速反应体系,测出此快速反应为一级反应,所测实验结果经与仪器相联的计算机系统以最小二乘法理论处理结果相一致。     

BESⅡ顶点探测器径迹组合触发判选系统

在ＢＥＳⅡ中顶点探测器代替了ＢＥＳ的中心漂移,建立了相应的触发判选子系统。介绍了ＢＥＳⅡ顶点探测器触发判选子系统的原理,构成,逻辑设计和结果。该系统是北京谱仪触发判选系统升级改进的主要项目之一。     

分光计调整的一种新方法

在分析分光调整原有实验步骤的基础上，总结出“贴近法”和“平行光管辅助找像法”等新的调整方法，开成分光计调整的新步骤。