高分辨星载海洋微波辐射测量技术发展综述

星载微波辐射计作为海洋观测的一种重要技术手段,能够全天时、全天候对海洋环境参数进行长期连续的观测,具有宽幅、高精度等特点,能够为数值预报、台风监测、防灾减灾等应用提供重要保障。随着海洋应用需求不断提升,星载海洋微波辐射探测技术也向着更高分辨率、更高精度的方向发展。文章对高分辨率海洋微波辐射测量新技术的概念、系统组成以及发展情况进行了介绍,包括基于密集馈源阵列的多波束推扫辐射计、集中式综合孔径辐射计以及分布式综合孔径辐射计。文章结合三种高分辨率微波辐射测量技术的特点和当前技术水平对未来星载海洋微波辐射测量技术的发展思路进行了讨论,对其中的重要的关键技术进行了梳理,并针对不同应用需求给出了发展建议。

亚波长光栅与法布里-珀罗滤光片集成的高性能光谱偏振分光器

光谱偏振成像技术是一种新型的光学成像技术,它不仅提高了目标的信息获取量,还降低了背景噪声,可以捕获目标细节,检测伪装目标。本文提出了一种将亚波长光栅与F-P滤光片相结合的光谱偏振测量器件,该器件可以获得超高光谱分辨率和偏振消光比,并且光谱和偏振可以灵活调控。本文设计了一种光谱偏振同时分光器,可同时获得4个光谱通道的斯托克斯参数。仿真结果表明,其光谱分辨率为217,偏振消光比为106。实验结果表明,亚波长光栅的偏振消光比大于500,透射率为90%。全介质F-P滤光片的光谱分辨率为30,在长波红外波段的透射率为60%。该设计方法具有通用性,可用于可见光、红外甚至太赫兹等波段。得益于这些优点,器件在微型偏振光谱仪和全斯托克斯偏振检测等领域有很大的应用潜力。

俾路支褐煤有机结构特征及大分子模型构建

以巴基斯坦俾路支褐煤(BL)为研究对象,由元素分析得出BL化学式为C_(167)H_(130)O_(53)N_(2)S。经X射线光电子能谱(XPS)分析BL有机结构中氧、氮和硫元素存在形式。利用傅里叶变换红外光谱(FT-IR)研究BL有机结构中主要官能团特征,-CH和-CH^(2)为BL脂肪族结构中主要官能团。BL中苯环主要取代形式为三取代和四取代。运用核磁共振光谱(^(13)C-NMR)探究BL有机结构碳骨架结构。BL分子结构中,芳香桥碳与周碳之比X_(BP)为0.21,碳主要由芳香碳和脂肪碳2部分构成,其中脂肪碳质量分数53.23%,芳香碳占比41.93%。芳香结构以苯环和萘环为主,氧主要以羧基、羰基、醚氧和酚羟基形式存在,而氮主要以吡咯氮形式存在,硫主要为噻吩。建立BL二维分子结构模型,通过Materials Studio对其进行加氢饱和,构建BL分子模型三维立体结构,进一步优化所得分子模型,空间效果显著,得到能量最低的BL三维结构模型,发现范德华能是BL分子结构稳定的关键因素。通过计算得到的BL模型结构^(13)C NMR谱图与试验所测谱图基本一致,验证了所构建BL结构模型的合理性。

基于HS-SPME-GC-MS探究压制及陈化对南川大树茶毛茶及其沱茶香气的影响

为探究南川大树茶毛茶压制前后香气成分的变化及陈化对其沱茶香气的影响,本文采用传统感官评审结合顶空固相微萃取-气相色谱-质谱联用仪(Headspace-solid phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS)对茶样香气进行分析,通过正交偏最小二乘法判别分析(Orthogonal partial least squares discriminationanalysis, OPLS-DA)建立判别模型,并基于变量投影重要性分析(Variableimportancein projection,VIP值)结合香气活度值(Odor activity value,OAV)筛选不同茶样中的特征香气。结果表明:南川大树茶毛茶压制前后与沱茶陈化处理后其香气评分存在显著差异(P<0.05)。通过HS-SPME-GC-MS从6个茶样中共鉴定出114种香气成分,与毛茶相比,压制后沱茶的香气种类及含量均明显降低,1-辛烯-3-醇等低沸点香气化合物损失较大;通过陈化处理的沱茶香气种类更为丰富,其中1,2-二甲氧基苯为陈化处理后沱茶样品中的特有物质。基于107种共有香气成分建立的OPLS-DA可实现对不同茶样的有效区分,以VIP值>1与OAV>1为标准共筛选出23种特征香气成分,苯乙醇、(E)-2-庚烯醛等17种香气成分为大树茶毛茶样品中重要的香气成分,反式-2-壬醛、反-2-辛烯醛等6种香气成分为大树茶沱茶样品中的重要香气成分。本研究为大树茶沱茶的加工贮藏提供参考。

Spectro M8型直读光谱仪分析生铁中硅、锰和磷

用 HB 30 0 0型磨样机制取样品 ,Spectro M8型直读光谱仪分析生铁中硅、锰和磷 ,方法可行 ,数据准确 ,取得了理想效果。

柠檬黄拉曼光谱、紫外可见吸收光谱的理论和实验研究

采用密度泛函理论(Density Functional Theory, DFT),在B3LYP/6-31+g(d, p)水平上对柠檬黄分子结构进行了优化,根据频率计算结果,绘制出拉曼光谱图并和实验获得的拉曼光谱谱图、表面增强拉曼光谱图进行了比对,实验和理论计算获得的拉曼光谱图基本上一致。基于势能函数分布的计算,对谱图信息丰富的500~2 000 cm^(-1)拉曼谱带的特征拉曼光谱进行了归属指认。基于含时密度泛函理论,计算了柠檬黄分子的激发态,理论计算得到柠檬黄分子的吸收光谱和实验采集得到的紫外-可见吸收光谱图进行了比对,分析了柠檬黄分子激发态的电子-空穴分布图。

多功能光谱仪定标方法

为了精确标定红外探测器的光谱响应函数,分别通过两点线性定标法、多点线性拟合定标法、非线性多项式拟合定标法以及远距离小面源定标法对多功能光谱辐射计进行标定,解算出辐射计的光谱响应系数和偏置系数,采用定标后的辐射计对不同温度黑体标准源的辐射亮度进行测量,并与黑体理论辐射亮度进行对比。结果表明,多点定标可减小噪声引起的随机误差和非线性响应引起的系统误差;当被测目标温度变化范围较小时,宜采用多点线性拟合定标,以减少噪声引起的随机误差带来的影响;当被测目标温度变化范围较大时,宜采用多点非线性拟合定标,以减少非线性响应引起的系统误差带来的影响;当被测目标温度较高时,光谱辐射计入瞳处信号较大,宜采用远距离小面源法标定,测量误差低于2%。定标后的测试精度优于国内外同类仪器。

温度场下功能梯度圆锥壳-环板振动特性分析

针对功能梯度圆锥壳-环板组合结构振动问题,本文采用一阶剪切变形理论和Rayleigh-Ritz法分析了温度场下组合结构的振动特性。组合结构位移变量采用谱几何法来表征,考虑材料参数与温度相关并引入人工边界弹簧建立了组合结构振动特性分析模型。数值算例中,通过将文中求解结果与文献解和有限元法结果进行对比验证了模型的正确性,进而分析尺寸、材料、温度和连接位置等参数对结构振动特性的影响。研究结果表明:组合结构基频随厚度增加而增加,随着幂律指数、半顶角和温度场参数增加而降低,随环板内径和连接位置变化会呈现非单一变化趋势。

The dawn−dusk asymmetry in mesosphere and lower thermosphere temperature disturbances during geomagnetic storms at high latitude

Utilizing observations by the Sounding of the Atmosphere using Broadband Emission Radiometry(SABER)instrument,we quantitatively assessed the dawn-dusk asymmetry in temperature disturbances within the high-latitude mesosphere and lower thermosphere(MLT)during the main phase of geomagnetic storms in this study.An analysis of five geomagnetic superstorm events indicated that during the main phase,negative temperature disturbances were more prevalent on the dawn side than on the dusk side in the high-latitude MLT region.Results of a statistical analysis of 54 geomagnetic storm events also revealed a notable disparity in temperature disturbances between the dawn and dusk sides.At high latitudes,38.2%of the observational points on the dawn side exhibited negative temperature disturbances(less than−5 K),whereas on the dusk side,this percentage was only 29.5%.In contrast,at mid-latitudes,these proportions were 34.1%and 36.5%,respectively,showing no significant difference.We also conducted a statistical analysis of temperature disturbances at different altitudes,which revealed an increase in the proportion of warming disturbances with altitude.Conversely,the proportion of cooling disturbances initially rose with altitude,reaching a peak around 105 km,and subsequently decreased.These temperature disturbance differences could be explained by the day-night asymmetry in vertical wind disturbances during storm conditions.

基于合作目标的空间目标尺寸反演模型

传统基于亮度的空间目标尺寸反演方法需结合探测器响应,其误差会影响尺寸反演的精度。为了解决这一问题,文章提出引入合作目标亮度信息来辅助尺寸反演的方法,将合作目标亮度信息与空间目标进行比对,消去误差较大的探测器响应,转化成精度更高的合作目标位置信息,从而实现反演精度的提高。首先建立了基于合作目标亮度和位置信息的空间目标观测模型,然后依据辐射度学推导空间目标尺寸反演解析式,给出计算误差,最后结合实例对模型进行验证。结果显示基于合作目标亮度信息的尺寸反演精度较传统方法提高约46.9%,说明引入合作目标辅助尺寸反演能够有效提升反演精度。

An Overview of MODIS Radiometric Calibration and Characterization

The Moderate Resolution Imaging Spectroradiometer （MODIS） is one of the key instruments for NASA＇s Earth Observing System （EOS）, currently operating on both the Terra and Aqua satellites. The MODIS is a major advance over the previous generation of sensors in terms of its spectral, spatial, and temporal resolutions. It has 36 spectral bands： 20 reflective solar bands （RSB） with center wavelengths from 0.41 to 2.1 μm and 16 thermal emissive bands （TEB） with center wavelengths from 3.7 to 14.4 μm, making observations at three spatial resolutions： 250 m （bands 1-2）, 500 m （bands 3-7）, and lkm （bands 8-36）. MODIS is a cross-track scanning radiometer with a wide field-of-view, providing a complete global coverage of the Earth in less than 2 days. Both Terra and Aqua MODIS went through extensive pre-launch calibration and characterization at various levels. In orbit, the calibration and characterization tasks are performed using its on-board calibrators （OBCs） that include a solar diffuser （SD） and a solar diffuser stability monitor （SDSM）, a v-grooved flat panel blackbody （BB）, and a spectro-radiometric calibration assembly （SRCA）. In this paper, we present an overview of MODIS calibration and characterization activities, methodologies, and lessons learned from pre-launch characterization and in-orbit operation. Key issues discussed in this paper include in-orbit efforts of monitoring the noise characteristics of the detectors, tracking the solar diffuser and optics degradations, and updating the sensor＇s response versus scan angle. The experiences and lessons learned through MODIS have played and will continue to play major roles in the design and characterization of future sensors.

Evaluation of Two Absolute Radiometric Normalization Algorithms for Pre-processing of Landsat Imagery

In order to evaluate radiometric normalization techniques, two image normalization algorithms for absolute radiometric correction of Landsat imagery were quantitatively compared in this paper, which are the Illumination Correction Model proposed by Markham and Irish and the Illumination and Atmospheric Correction Model developed by the Remote Sensing and GIS Laboratory of the Utah State University. Relative noise, correlation coefficient and slope value were used as the criteria for the evaluation and comparison, which were derived from pseudo-invarlant features identified from multitemporal Landsat image pairs of Xiamen （厦门） and Fuzhou （福州） areas, both located in the eastern Fujian （福建） Province of China. Compared with the unnormalized image, the radiometric differences between the normalized multitemporal images were significantly reduced when the seasons of multitemporal images were different. However, there was no significant difference between the normalized and unnorrealized images with a similar seasonal condition. Furthermore, the correction results of two algorithms are similar when the images are relatively clear with a uniform atmospheric condition. Therefore, the radiometric normalization procedures should be carried out if the multitemporal images have a significant seasonal difference.

Photocarrier radiometry for noncontact evaluation of space monocrystalline silicon solar cell under low-energy electron irradiation

A space monocrystalline silicon（c-Si） solar cell under low-energy（〈 1 MeV） electron irradiation was investigated using noncontact photocarrier radiometry（PCR）. Monte Carlo simulation（MCS） was employed to characterize the effect of different energy electron irradiation on the c-Si solar cell. The carrier transport parameters（carrier lifetime, diffusion coefficient, and surface recombination velocities） were obtained by best fitting the experimental results with a theoretical one-dimensional two-layer PCR model. The results showed that the increase of the irradiation electron energy caused a large reduction of the carrier lifetime and diffusion length. Furthermore, the rear surface recombination velocity of the Si：p base of the solar cell at the irradiation electron energy of 1 Me V was dramatically enhanced due to 1 MeV electron passing through the whole cell. Short-circuit current（I sc） degradation evaluated by PCR was in good agreement with that obtained by electrical measurement.

Thermal annealing induced photocarrier radiometry enhancement for ion implanted silicon wafers

An experimental study on the photocarrier radiometry signals of As^＋ ion implanted silicon wafers before and after rapid thermal annealing is performed. The dependences of photocarrier radiometry amplitude on ion implantation dose （1×10^11-1×10^16/cm^2）, implantation energy （20-140 keV） and subsequent isochronical annealing temperature （500- 1100℃ are investigated. The results show that photocarrier radiometry signals are greatly enhanced for implanted samples annealed at high temperature, especially for those with a high implantation dose. The reduced surface recombination rate resulting from a high built-in electric field generated by annealing-activated impurities in the pn junction is believed to be responsible for the photocarrier radiometry signal enhancement. Photocarrier radiometry is contactless and can therefore be used as an effective in-line tool for the thermal annealing process monitoring of the ion-implanted wafers in semiconductor industries.

Two-Dimensional Terahertz Time-Domain Spectroscopy and Its Applications

In this work, we review the developing progress of two-dimensional terahertz time-domain spectroscopy（THz-TDS） and its diverse applications, including analyzing the polarization of THz radiation from a laser-induced plasma source and studying the corresponding physical mechanism, and characterizing the optical properties of crystals, etc.

Interpretation of Geological Structures Hosting Potential Gold Deposits in the Konongo Gold Mine Using Airborne Magnetic, Electromagnetic and Radiometric Datasets

The renewed interest in the reactivation of the defunct National Konongo Gold Mine located in the Ashanti Greenstone Belt, calls for a further probe into its geology and the associated mineral hosting structures to discover its mineralization potential. In order to achieve this, airborne magnetic, radiometric and electromagnetic datasets were interpreted to determine the potential gold hosting features in the studied area. The results show the area to consist of the metasediment, the metavolcanic, Tartwaian Formation and their associated granitoids. Results also show that the Tarkwaian sediments, observed largely in the north-eastern side of the site;widen out substantially and truncate in the south. The analysis of the structure lineaments using a rose diagram reveals three main tectonic structures trending in N-S, NNW-SSE, and third the structure trending in the NNE-SSW to NE-SW directions in the area. The dominant structures in the area, form 90% of all the delineated structures and trend in the NE-SW and NNE-SSW direction with the remaining 10% trending in the N-S and NNW-SSE. These structures are associated with the major shear and fracture zones located mainly at the contact between the basin sediments and volcanic belt and also associated with the Tarkwaian Formation. The mapped potential gold mineralization zones located mainly at the contact between the metasediment and the metavolcanic units of the Birimian Supergroup, as well as the Tarkwaian Formation, were mapped by integrating the structures, alteration zones as well as the complex dyke systems. This paper delineates the prominent geological structures with the potential of hosting economic gold mineralization in and around the Konongo Gold Mine.

Investigation of the interaction between indigotin and two serum albumins by spectroscopic approaches

The binding characteristics of indigotin with human serum albumin （HSA） and bovine serum albumin （BSA） have been investigated by various spectroscopic techniques. Spectroscopic analysis revealed that the quenching mechanism between indigotin and HSA/BSA belonged to the static quenching. The displacement experiments suggested that indigotin primarily bound to tryptophan residues on proteins within site I. The thermodynamic parameters indicated that the binding of indigoti^HSA/BSA mainly depended on the hydrophobic interaction. The binding distance of indigotin to HSA/BSA was evaluated. The results by synchronous fluorescence, three- dimensional fluorescence, Fourier Transform Infrared spectroscopy （FT-IR） and circular dichroism （CD） spectra showed that the conformation of proteins altered in the presence of indigotin.

Spectrophotometric Methods for Simultaneous Determination of Amlodipine Besylate and Atenolol in Their Tablet Dosage Form

Three simple,specific,accurate and precise spectrophotometric methods are developed for simultaneous determination of amlodipine besylate(AM)and atenolol(AT)in tablets.The first method is dual wavelength spectrophotometry(DW).The second method is ratio subtraction(RS)which depends on subtraction of the plateau values from the ratio spectrum,coupled to first derivative of ratio spectra(1 DD).The third method applies bivariate calibration method using 210and 225nm as an optimum pair of wavelength for amlodipine and atenolol.The calibration curves are linear over the concentration range of 4~40μg·mL-1 for both drugs.The specificity of the developed methods is investigated by analyzing laboratory prepared mixtures of the two drugs and their combined dosage form.The two methods are validated as per ICH guidelines and can be applied for routine quality control testing.

A rapid and sensitive liquid chromatography-tandem mass spectrometric assay for duloxetine in human plasma:Its pharmacokinetic application

This paper describes a simple, rapid and sensitive liquid chromatography tandem mass spectrometry assay for the determination of duloxetine in human plasma. A duloxetine stable labeled isotope （duloxetine ds） was used as an internal standard. Analyte and the internal standard were extracted from 100 btL of human plasma via solid phase extraction technique using Oasis HLB cartridges. The chromatographic separation was achieved on a Cl8 column by using a mixture of acetonitrile 5 mM ammonium acetate buffer （83：17, v/v） as the mobile phase at a flow rate of 0.9 mL/min. The calibration curve obtained was linear （r2≥0.99） over the concentration range of 0.05 101 ng/mL. Multiple-reaction monitoring mode （MRM） was used for quantification of ion transitions at rn/z 298.3/154.1 and 303.3/159.1 for the drug and the internal standard, respectively. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 2.5 min for each sample made it possible to analyze more than 300 plasma samples per day. The proposed method was found to be applicable to clinical studies.

SPECTRO M8光谱仪一例计算机故障的排除

本文介绍了一例SPECTRO M8计算机故障及其排除措施。