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层析型线阵推扫成象光谱技术及其仿真研究 总被引:3,自引:3,他引:0
本文设计了一种层析型线阵推扫成象光谱仪。与色散型推扫成象光谱仪或干涉型推扫成象光谱仪不同的是,它用线阵CCD代替面阵CCD,同时又具有高通量、多通道、高信噪比、结构简单、轻量等优点。其基本原理是利用光栅的多级衍射实现视场条带目标的一维空间和一维光谱组成的“空间-光谱平面”到一维投影象的Radon变换,然后由逆Radon变换重构二维数据(一维光谱和一维空间),另一维空间信息通过推扫便可得到。文章还提供了重构算法和计算机仿真试验结果,验证了算法和方案的可行性。 相似文献
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《光谱学与光谱分析》2020,(6)
共焦布里渊光谱技术因其具有非接触、无损伤、高空间分辨等优点,在生物医学、物理化学以及材料科学中被广泛应用。由于布里渊散射频移较低、强度较弱,在弹性散射光没有被充分抑制的情况下,布里渊散射光容易受到弹性散射光的影响,导致光谱测量结果精度的下降,而且传统共焦布里渊光谱系统仍存在光谱轴向分辨力与层析能力不足等缺点,严重限制了共焦布里渊光谱探测系统在高散射样品以及长工作距离光谱探测领域中的应用。为改善共焦布里渊光谱探测系统的抗弹性散射能力、光谱轴向分辨力以及层析能力,构建了一种D形分光瞳共焦布里渊光谱探测系统。该系统通过侧向照明与侧向收集的方式消除背向散射,降低弹性散射强度,有效抑制弹性散射对布里渊散射的干扰,进而提高共焦布里渊光谱探测系统的抗弹性散射能力。通过D形光瞳对照明点扩散函数与收集点扩散函数进行调制,利用斜入射的方式使照明点扩散函数与收集点扩散函数仅在焦平面上发生重叠,在轴向上实现三维点扩散函数的压缩,有效去除离焦光谱信息对焦面光谱信息的干扰,降低轴向光谱强度响应曲线的半高全宽与全高全宽,进而达到提高共焦布里渊光谱探测系统的光谱轴向分辨力以及层析能力的效果。实验表明:相比于共焦布里渊光谱探测系统, D形分光瞳共焦布里渊光谱探测系统的抗弹性散射能力与层析能力得到大幅提升,通过优化光瞳参数,其光谱轴向分辨力可以提高30%以上,进而可以有效解决多层样品中的光谱串扰问题。D形分光瞳共焦布里渊光谱探测系统作为一种具有高层析能力、抗弹性散射能力强的布里渊光谱探测系统,为布里渊光谱技术在现代前沿基础学科领域中的进一步应用提供了有力保证。 相似文献
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为了研究层析滤纸在表面增强拉曼光谱和层析技术联用中的影响。在785 nm激发波长下分别测试了层析滤纸, 涂布银胶后层析滤纸的拉曼特征谱, 以及氧化乐果在层析滤纸上的拉曼光谱和表面增强拉曼光谱(SERS)。结果表明, 层析滤纸在800~1500 cm-1光谱区域具有丰富的拉曼特征峰, 分析认为主要来源于纤维素, 并对其进行了归属; 涂布银胶后, 由于银颗粒的作用, 层析滤纸拉曼强度整体降低, 并发生特征峰相对强度的变化; 同时, 氧化乐果在层析滤纸上的SERS谱也表明涂布银胶能够有效抑制层析滤纸拉曼特征峰, 增强待测物质拉曼强度, 但在800~1500 cm-1光谱区域仍需考虑层析滤纸的影响。 相似文献
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衍射光栅干涉仪用单色扩展光源照明并适当地进行空间滤波,可看成重要的成象系统,其振幅具有线性特征。若加宽光源的光谱,则该系统的照度也是线性的。 相似文献
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编码孔成象(CAI)是一种高分辨率、高信噪比、高集光效率和大视场的成象技术。可适用的技术领域有:脉冲射线成象、实时图象跟踪、层析摄影术(tomography)等高技术领域本文探讨了CAI技术的一般理论,重点讨论了菲涅耳波带片的编码成象及解码复原的原理、方法、实验及处理结果并指出了实验难点及结果误差。 相似文献
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基于多线光源阵列光刻系统降低一个方向的衍射效应原理,设计出了用于光刻计量光栅的复眼棱镜非接触光刻曝光系统。此系统具有简单的光学结构,即将原来的二次成象变为一次成象,也就是说,用复眼棱镜组代替了复眼柱面透镜组和准直物镜组。为了扩展系统工作范围,还设计了几组柱面倍率透镜系统,这样就可以复制光刻出任意宽的光栅线条。 相似文献
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利用X射线衍射技术(XRD)测试了涂层及其基体材料的应力及其变化规律,建立了一种涂层结合界面应力检测系统,进行界面结合状态的检测研究.利用涂层从基体脱粘前后的界面应力变化量,结合涂层材料的物性参数和涂层-基体系统温度场参数,用涂层残余应力衍射峰来表征涂层与基体的结合强度,创立一种研究检测涂层结合强度理论的实验新方法,适用于各种热障涂层的界面结合强度测量.
关键词:
X射线衍射法(XRD)
界面结合强度
涂层
残余应力 相似文献
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《Physics letters. A》2020,384(7):126164
An artificial molecule consisting of an SQD and an MNR embedded in 3D photonic crystal is proposed to realize EIG. Using the quantum mechanical density matrix approach, we have derived an expression of the absorption coefficient in the SQD in presence of MNR. Nanoparticle geometry can modify the local fields that determine SQD-MNP coupling and to engineer the hybrid optical response. The probe absorption is reduced via a strong coupling field, demonstrating spectral transparency window. It is worth noting that the background affects the relaxations of SQD. So, by making use of 3D photonic crystal as the background medium, reduced decay rate and consequently substantial local-field enhancement rate are provided. Based on EIT effect and a strong standing-wave field, diffraction grating is achievable. The first-order diffraction intensity can reach its maximum by tuning the system parameters. This model may be useful in designing new devices in all-optical communication. 相似文献
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计算分光光度法同时测定铁、铝、钪 总被引:1,自引:0,他引:1
基于铬天青S-CTMAB-丙酮与Fe,Al,Sc的显色体系中各组分吸收光谱灵敏度,而选择性差的特点,本文提出一种改进矩阵法,并同时测定了合成样品中三组分的含量取得了满意结果。 相似文献
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可调谐二极管激光吸收光谱(TDLAS)技术用于气体浓度检测时,会受到谐波检测中基线漂移及噪声的影响,因此如何去除系统噪声一直是研究的热点。分析了连续截断信号和构造hankel矩阵两种不同方法下,奇异值分解(SVD)对TDLAS系统检测的理论意义。将二次谐波信号分别用该方法进行矩阵化排列和奇异值分解,选取适当阈值将部分奇异值置零并重构矩阵,得到了这两种方法对基线纠漂和去噪的不同效果。实验证明,奇异值分解方法不需加入额外系统部件、不需通零气扣除背景,就能够快速有效地去除TDLAS系统噪声,而构造hankel矩阵的方法适用于去除高频噪声,连续截断信号的方法适用于进行基线纠漂。将该方法应用于实际TDLAS系统氨气检测时的二次谐波,系统噪声去除率达80%。 相似文献
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Parallel magnetic resonance imaging (pMRI) and compressed sensing (CS) have been recently used to accelerate data acquisition process in MRI. Matrix inversion (for rectangular matrices) is required to reconstruct images from the acquired under-sampled data in various pMRI algorithms (e.g., SENSE, GRAPPA) and CS. Singular value decomposition (SVD) provides a mechanism to accurately estimate pseudo-inverse of a rectangular matrix. This work proposes the use of Jacobi SVD algorithm to reconstruct MR images from the acquired under-sampled data both in pMRI and in CS. The use of Jacobi SVD algorithm is proposed in advance MRI reconstruction algorithms, including SENSE, GRAPPA, and low-rank matrix estimation in L + S model for matrix inversion and estimation of singular values. Experiments are performed on 1.5T human head MRI data and 3T cardiac perfusion MRI data for different acceleration factors. The reconstructed images are analyzed using artifact power and central line profiles. The results show that the Jacobi SVD algorithm successfully reconstructs the images in SENSE, GRAPPA, and L + S algorithms. The benefit of using Jacobi SVD algorithm for MRI image reconstruction is its suitability for parallel computation on GPUs, which may be a great help in reducing the image reconstruction time. 相似文献
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纳米碳管复合凝胶玻璃结构及谱学性能研究 总被引:1,自引:1,他引:0
用物理掺杂工艺将纳米碳管引入二氧化硅凝胶玻璃基质,成功制备了纳米碳管复合凝胶玻璃,采用X射线衍射、透射电子显微镜、紫外-可见吸收光谱、红外光谱、拉曼光谱等测试方法对其结构和谱学性能进行了表征。结果表明,通过优化掺杂工艺能够实现纳米碳管与基质的均匀复合,纳米碳管本身的结构在掺杂过程中并未发生改变。纳米碳管的引入对二氧化硅凝胶玻璃基质的紫外-可见吸收光谱和红外光谱未产生显著影响。 相似文献
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《Composite Interfaces》2013,20(2-3):143-158
Poly(lactic acid) (PLA)/layered silicate nanocomposites have successfully been prepared using the solution route. Two types of organically modified nanoclays, namely, MEE and MAE have been used. The nanostructure, as observed from wide angle X-ray diffraction, indicates an intercalated hybrid for both PLA–MEE and PLA–MAE, and depends on the type of organic modifier used. Intercalation is higher in PLA–MEE as compared to PLA–MAE system. Crystallite dimensions of nanoclays and nanocomposites have been calculated from the Scherrer equation. Crystallite size of nanocomposites is higher than that of pure nanoclay, which in turn affects the properties of the nanocomposites. Wide angle X-ray diffraction patterns also suggest that PLA and its nanocomposites are predominantly amorphous before annealing but, after annealing, PLA and its nanocomposites are fairly crystalline. The crystallinity of the nanocomposites has decreased in comparison to neat polymer suggesting some sort of interaction between organically modified nanoclay and polymer. The nanohybrids show significant improvement in the thermal properties of the matrix as compared to pristine polymer. The nature of interaction between nanoparticles and polymer is higher in PLA–MEE against PLA–MAE, as evident from the lower value of the heat of fusion in the case of PLA–MEE. The nanoparticles act as nucleating agent, and thereby, control the spherulite dimension of the matrix. The comparison of biodegradation of PLA and its nanocomposites has been studied in several media. Biodegradability of PLA has significantly been enhanced in the presence of nanoclays which has been explained on the basis of amorphous content in the polymer matrix. Finally, the regulated biodegradation has been discussed. 相似文献
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Snapshot hyperspectral imaging simultaneously acquires spatial and spectral information about a scene. We report on the first, to our knowledge, all-reflective snapshot hyperspectral imager in the form of a computed tomography imaging spectrometer (CTIS). The reflective design allows for instrument simplicity for applications in the ultraviolet and infrared. To realize a CTIS in a reflective Offner configuration, a reflective two-dimensional computer-generated hologram grating is fabricated on a convex spherical substrate by direct-write electron-beam lithography. Furthermore, a reconfigurable reflective field stop is implemented with a micromirror array to provide high-contrast spatial-spectral filtering, region-of-interest selection, and spatial structure formation. 相似文献