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991.
将分子成像技术和高光谱技术相结合,研制了基于AOTF(Acousto-optic Tunable Filters)的分子高光谱成像系统。系统由显微镜、分光仪、CCD镜头、图像数据采集卡和计算机等几部分组成。在综合考虑各功能部件的性能及相互的制约关系的基础上,分析了系统的性能指标,系统的光谱范围从550~1 000 nm,可采集200个波段,空间分辨率可达0.061 5 μm,光谱分辨率可达2 nm,当CCD工作在积分模式下采集速度可达到2.612 5 s·B-1,当CCD工作在非积分模式下可达到约0.11 μs·B-1。由于受系统光源和光路中透镜及传感器性能的影响,采集到的图像数据需要进行预处理,文中提出一种空间维和光谱维联合校正的灰度校正系数算法,并给出算法的具体实现。以白血病的血液作样本,通过对比校正前后的单波段图像、伪彩色图像和光谱曲线,说明校正算法的有效性,为后续的光谱图像数据分析提供了有效的数据。 相似文献
992.
Jari Toivanen & Cornelis W. Oosterlee 《高等学校计算数学学报(英文版)》2012,5(1):85-98
We present an algebraic version of an iterative multigrid method for
obstacle problems, called projected algebraic multigrid (PAMG) here.
We show that classical algebraic multigrid algorithms can easily be
extended to deal with this kind of problem. This paves the way for
efficient multigrid solution of obstacle problems with partial
differential equations arising, for example, in financial engineering. 相似文献
993.
994.
Covalently cross‐linked microporous polymers are a new class of highly cross‐linked porous network materials with large surface area and potential superiority in sample pretreatment. In this work, a covalently cross‐linked microporous polymer was well designed and synthesized by condensation of acylhydrazines in terephthalic dihydrazide with aldehyde groups in 1,3,5‐benzenetricarboxaldehyde. The adsorption mechanism was explored and discussed based on π‐π stacking interaction and steric effect. Then, a covalently cross‐linked microporous polymer was employed as the adsorbent of online micro‐solid‐phase extraction coupled with high‐performance liquid chromatography for the enrichment and analysis of trace pesticide residues in citrus fruits. The method was successfully applied to the online analysis of sugar orange and Huangdigan samples with the detection limits of 0.10–0.30 μg/kg. It was satisfactory that chlorpifos and triazophos in real sugar orange and Huangdigan samples could be actually found and quantified at concentrations of 0.20 and 0.51 mg/kg, respectively. The recoveries of sugar orange and Huangdigan samples were in the range of 70.0–103 and 74.0–119% with relative standard deviations of 0.4–9.7 and 0.5–9.2% (n = 3), respectively. The proposed method was accurate, reliable, and convenient for the online simultaneous analysis of trace pesticide residues in citrus fruits. 相似文献
995.
The main purpose of this study is to survey numerically comparison of two- phase and single phase of heat transfer and flow field of copper-water nanofluid in a wavy channel. The computational fluid dynamics (CFD) prediction is used for heat transfer and flow prediction of the single phase and three different two-phase models (mixture, volume of fluid (VOF), and Eulerian). The heat transfer coefficient, temperature, and velocity distributions are investigated. The results show that the differences between the temperature fie].d in the single phase and two-phase models are greater than those in the hydrodynamic tleld. Also, it is found that the heat transfer coefficient predicted by the single phase model is enhanced by increasing the volume fraction of nanoparticles for all Reynolds numbers; while for the two-phase models, when the Reynolds number is low, increasing the volume fraction of nanoparticles will enhance the heat transfer coefficient in the front and the middle of the wavy channel, but gradually decrease along the wavy channel. 相似文献
996.
997.
ZHAO Yanyan WANG Liheng GUO Zhimou CHI Xiaofei MA Xiaochi QI Yan FANG Shinong LI Xiuling LIANG Xinmiao 《高等学校化学研究》2015,31(1):44-52
Detection and determination of multi-phosphopeptides from protein digestion products are difficult due to the low abundance and ion-suppression effect arised from the existence of their high-abundance counterparts. Click OEG-CD[olio(ethylene glycol)(OEG) linked β-cyclodextrin(CD)] matrix has shown excellent performance in phosphopeptide enrichment. However, few multi-phosphopeptides were detected previously. In this investigation, an improved method aiming at enhancing the enrichment selectivity and mass spectrometry(MS) detection of multi-phosphopeptide was developed via optimizing the sample loading amount on per mg of matrix. Mass spectra were obtained on a Nano liquid chromatography-electrospray ionization-quadrupole time of flight-mass spectrometry (LC-ESI-qTOF-MS). The enrichment selectivity of double-phosphopeptide could be enhanced with the increase of loading amount on per mg of matrix when taking the mixture of mono-, double-, and non-phosphopeptides as probe. Furthermore, the multi-phosphopeptide enrichment selectivity was enhanced under the condition of optimized loading amount when taking the product of typtic digestion α-casein as test sample. When the loading amount was 573 pmol/mg matrix, up to 20 α-casein phosphopeptide signals(including 15 multi-phosphopeptides) were detected. The result is much better than that of our previous report. The reduction of ion-suppression effect arised from the existence of high-abundance non-or mono-phosphopeptides and the stronger interactions between multi-phosphopepides and the matrix were contributed to the result. The study could be helpful to the better utilization of Click OEG-CD matrix in the enrichment of multi-phosphopeptide from complex biosamples in the subsequent investigation. 相似文献
998.
刘莹 《浙江大学学报(理学版)》2010,37(5):511-514
利用等价测度和鞅的方法,以股票价格为选择重设点依据的情况下推导了随机时间重置期权中的欧式看涨期权的定价公式. 相似文献
999.
近年来太赫兹技术因其重要的理论研究价值和广泛的应用前景引起了科学界的普遍关注。太赫兹光谱技术作为太赫兹科学发展的主要方向之一,可分为频域光谱与时域光谱两种。它的出现解决了太赫兹波段下无法产生宽带辐射源的难题,使得光谱学上存在的太赫兹断层得以填补。随着这项技术的发展,对太赫兹波段下物质特性的研究也逐步拓展到生物医学、材料、通信、安检为代表的各个领域。从产生原理、性能特点、应用领域等方面对两种光谱进行比较,进而阐述了两种太赫兹光谱的优缺点以及其应用优势。 相似文献
1000.