共查询到20条相似文献,搜索用时 140 毫秒
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本文提出一种在光学相关识别中改善相关峰锐度的方法。在制作匹配滤波器时利用记录介质的非线性突出输入图象的边缘,从而实现了相关峰的锐化,文中详述了该方法的实现过程及理论基础,并给出了光学实验和计算机模拟实验的结果。 相似文献
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本文提出了一个分析非线性系统瞬变过程的新计算方法。这个方法首先把非线性系统用非线性及线性的R,L,C线路元件等效。从等效线路选择适当变量,用线路分析法则写成特定形式的非线性微分方程组。然后在相平面上用我们提出的图解方法进行积分来求解方程。这方法具有下列优点:(1)可以从非线性元件的实验曲线直接求微分方程的解,不必先求出非线性函数的解析表示式;(2)计算方便,工具简单,分析过程的物理图象清楚;(3)有一定的精确度。应用这个方法分析了隧道二极管的几种基本运用线路。得出的计算结果与实验和用电子计算机计算的结果符 相似文献
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在学习高中物理的过程中,我们经常利用图象的斜率求解某个物理量.比如:在运动学中,利用s-t图象的斜率求物体运动速度;利用u-f图象的斜率求物体运动的加速度;在电学中,利用U-I图象的斜率求电阻.在实验中也经常利用图象来处理数据,例如在测定“玻璃折射率”的实验中,就可以做出sin i-sin r的图象,然后利用图象的斜率求玻璃的折射率.利用上述方法求物理量的关键是:正确求出图象的斜率. 相似文献
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利用非线性效应的全矢量模型和狭缝波导的有限元模场求解法,系统地研究了狭缝波导结构和包层材料对其非线性和功率限制特性的影响.研究结果表明,狭缝波导的硅臂宽度、狭缝宽度、硅层高度和包层材料均影响其非线性和功率限制特性.对于空气包层狭缝波导,不同结构参数下的最高功率限制因子对应的非线性系数均高于20 W^-1·m^-1,而最低非线性系数6.5 W^-1·m^-1均出现在模式截止附近,泄露损耗较大,功率限制较弱,故空气包层狭缝波导无法同时实现低非线性和高功率限制;如果在狭缝波导上包覆二氧化硅,则可以同时获得低非线性和高功率限制,非线性系数可低至4.12 W^-1·m^-1,同时功率限制因子可达42%. 相似文献
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《光子学报》2020,(2)
利用非线性效应的全矢量模型和狭缝波导的有限元模场求解法,系统地研究了狭缝波导结构和包层材料对其非线性和功率限制特性的影响.研究结果表明,狭缝波导的硅臂宽度、狭缝宽度、硅层高度和包层材料均影响其非线性和功率限制特性.对于空气包层狭缝波导,不同结构参数下的最高功率限制因子对应的非线性系数均高于20 W~(-1)·m~(-1),而最低非线性系数6.5 W~(-1)·m~(-1)均出现在模式截止附近,泄露损耗较大,功率限制较弱,故空气包层狭缝波导无法同时实现低非线性和高功率限制;如果在狭缝波导上包覆二氧化硅,则可以同时获得低非线性和高功率限制,非线性系数可低至4.12 W~(-1)·m~(-1),同时功率限制因子可达42%. 相似文献
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A. A. Volod’kin G. E. Zaikov L. N. Kurkovskaya E. B. Burlakova 《Russian Journal of Physical Chemistry B, Focus on Physics》2011,5(5):836-845
The energies of formation, enthalpies, and entropies of the conformers of 1-(carboxy)-1-(N-methylamide)-2-(3′,5′-di-tert-butyl)-4-hydroxyphenyl)-propionic acid and sodium and potassium 1-(carboxy)-1-(N-methylamide)-2-(3′,5′-di-tert-butyl)-4-hydroxyphenyl)-propionates are calculated by quantum-chemical methods in the PM6 approximation. A doubling of signals
in the 1H NMR spectrum of the first conformer is observed, which merge into singlets when the compound is heated. Changes in the structure
of the conformers and donor-acceptor complexes (solvates) occur with the preservation of the metal-ligand coordination bond.
Calculations of the characteristics of 1-(carboxy)-1-(N-methylamide)-2-(3′,5′-di-tert-butyl)-4-hydroxyphenyl)-propionic acid and sodium and potassium 1-(carboxy)-1-(N-methylamide)-2-(3′,5′-di-tert-butyl)-4-hydroxyphenyl)-propionates in the PM6 approximation make it possible to predict the structure and properties of
the solvated structures. The energies of homolysis of the H-O bond D
(OH) are calculated, and a linear dependence of the antioxidant activity on D
(OH) for the structures of the studied compounds is demonstrated. The results make it possible to predict the properties of antioxidants
in the biological environment. 相似文献
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从川续断干燥根中分离得到一种常春藤皂苷元型三萜皂苷(化合物1),其结构被鉴定为3-O-[β-D-吡喃木糖(1-4)-β-D-吡喃葡萄糖(1-4)][α-L-吡喃鼠李糖(1-3)]-β-D-吡喃葡萄糖(1-3)-α-L-吡喃鼠李糖(1-2)-α-L-吡喃阿拉伯糖-常春藤皂苷元28-β-D-吡喃葡萄糖(1-6)-β-D-吡喃葡萄糖脂苷,该文利用HSQC-TOCSY技术,并结合1H-1H COSY、HSQC、HMBC等二维谱技术对该化合物13C,1H化学位移进行了明确归属. 相似文献
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利用红外光谱法及双指标序列法对不同产地和不同品种灵芝进行红外光谱的特征峰研究,结果表明:不同产地和不同品种的绝大多数灵芝红外光谱具有相似的特征峰, 其共有峰率可达到91.67%以上,但菌丝体品种其共有峰率达到52.94%~58.82%之间,变异峰率可达29.41%~66.67%之间,主要变异峰在指纹图谱区域1 460.9~1 423.7 cm-1之间出现阶梯峰。灵芝红外光谱明显的特征峰主要显示为多糖的特征峰型并伴有蛋白质谱带。在3 377.8~3 396.5 cm-1处有明显的宽而强的吸收峰, 在2 924.2~2 925.1 cm-1有小肩峰, 在1 635.8~1 650.3 cm-1处有中等强度的吸收峰, 在1 372.5~1 375.2 cm-1处有中等强度的吸收峰, 在1 074.8~1 075.3和1 043.2~1 045.2 cm-1处有很强的吸收分叉尖峰, 在指纹图谱区域891.0~894.8 cm-1处有明显的弱峰。在指纹图谱区域563.10~574.7 cm-1有中等强度的吸收峰。 相似文献
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静态抑制荧光法和流动注射抑制荧光法测定微量甲醛的研究 总被引:6,自引:0,他引:6
利用甲醛在中性或弱酸性条件下对亚硫酸盐-邻苯二甲醛-铵盐体系具有抑制作用,建立了测定甲醛的静态抑制荧光法和流动注射抑制荧光法。研究了测定甲醛的最佳条件。在最佳条件下,静态抑制荧光法测定甲醛的线性范围为0.10~1.60 μg·mL-1, 检测限为0.046 μg·mL-1;流动注射抑制荧光法测定甲醛的线性范围为0.10~2.00 μg·mL-1,检测限为0.085 μg·mL-1。用于河水中甲醛测定,与乙酰丙酮分光光度法(GB13197—91)比较,误差分别为0.83%和1.25%。 相似文献
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氮化铝结构的高温Raman光谱分析 总被引:2,自引:2,他引:0
本文测量了氮化铝在不同温度下的Raman光谱 ,并确定了氮化铝的光学声子模E2 1、A1(TO)、E2 2 、E1(TO)、A1(LO)和E1(LO)Raman散射峰的频率 ,它们分别为 2 5 2cm- 1、6 1 4cm- 1、6 5 8cm- 1、6 72cm- 1、894cm- 1和 91 2cm- 1,其中光学声子模A1(TO)、E2 2 的Raman散射峰比较明显。随着温度的升高 ,A1(TO)、E2 2 散射峰的频率向低波数方向变化 ,表明氮化铝粉末压制体中存在的压应力逐渐减小 ;这两个散射峰的半高宽逐渐增大 ,说明随着温度的升高 ,存在氮原子和铝原子的扩散使得氮化铝粉末压制体中晶体结构逐渐发生变化。由于氮化铝粉末本身在空气中易与水蒸气发生反应 ,生成的Al(OH) 3 或AlOOH在加热过程会发生分解 ,干扰样品高温Raman光谱测量。 相似文献
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Beaty-Travis LM Moule DC Liu H Lim EC Judge RH 《Journal of Molecular Spectroscopy》2001,205(2):232-238
The fluorescence excitation spectrum of formic acid monomer (HCOOH) was recorded in the 268-257 nm region under relatively high resolution. The cooling conditions of a rotating slit-jet nozzle simplified the rotational structure and allowed for a combination line-by-line least-squares/band-contour analysis and the determination of the rotational constants. The 0(0)(0) and 9(1)(0) bands were each simultaneously fitted to a combination of c-type and b-type bands. The coexistence of the two band types is a consequence of the very small separation between the 0(+) and 0(-) levels of the inversion mode, nu(8), brought about by the pyramidal conformation of the upper electronic state. In contrast, the 9(2)(0) band shows a splitting of 0.288 cm(-1) and is a consequence of the increased torsion-inversion coupling at higher energies. The 8(1)(0) band could only be approximately modeled using band-contour techniques with an estimated 1(+)-1(-) splitting of 0.5 cm(-1). The assignments, the observed, and calculated line positions used in the least-squares analyses are available in electronic form from the publisher as supplementary material. Copyright 2001 Academic Press. 相似文献
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蓝玉髓是中国台湾所产的名贵宝石之一,素有"台湾蓝宝"的美誉.文章通过红外吸收光谱和激光拉曼光谱,对不同颜色及质地的台湾蓝玉髓的振动光谱特征进行了研究.结果表明,台湾蓝玉髓均显示典型的石英质玉石的振动光谱特征.其红外吸收光谱主要表现为:1 250~1 110 cm-1为最强吸收区,属Si-O非对称伸缩振动,800~600 cm-1间中等强度的吸收窄带,由Si-O-Si对称伸缩振动致,Si-O弯曲振动位于600~300 cm-1内.台湾蓝玉髓样品的激光拉曼光谱散射峰主要分布在499 cm-1,464 cm-1和214~208cm-1处,分别归属为"Moganite"石英中的Si-O对称弯曲振动、Si-O弯曲振动和[SiO4]的旋转振动或平移振动. 相似文献
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This Letter theoretically discusses quasiparticle states and nuclear spin relaxation rates T1-1 in the quasi-one-dimensional superconductor (TMTSF)2PF6 under a magnetic field applied parallel to the conduction chains. We study the effects of Josephson-type vortices on T1(-1) by solving the Bogoliubov-de Gennes equation for p-, d- or f-wave pairing interactions. In the presence of line nodes in pairing functions, T1(-1) is proportional to T in sufficiently low temperatures because quasiparticles induced by vortices at the Fermi energy relax spins. We also try to identify the pairing symmetry of (TMTSF)2PF6. 相似文献
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Achterberg A Ackermann M Adams J Ahrens J Andeen K Atlee DW Bahcall JN Bai X Baret B Bartelt M Barwick SW Bay R Beattie K Becka T Becker JK Becker KH Berghaus P Berley D Bernardini E Bertrand D Besson DZ Blaufuss E Boersma DJ Bohm C Bolmont J Böser S Botner O Bouchta A Braun J Burgess C Burgess T Castermans T Chirkin D Christy B Clem J Cowen DF D'Agostino MV Davour A Day CT De Clercq C Demirörs L Descamps F Desiati P Deyoung T Diaz-Velez JC Dreyer J Dumm JP Duvoort MR Edwards WR Ehrlich R 《Physical review letters》2006,97(22):221101
On 27 December 2004, a giant gamma flare from the Soft Gamma-Ray Repeater 1806-20 saturated many satellite gamma-ray detectors, being the brightest transient event ever observed in the Galaxy. AMANDA-II was used to search for down-going muons indicative of high-energy gammas and/or neutrinos from this object. The data revealed no significant signal, so upper limits (at 90% C.L.) on the normalization constant were set: 0.05(0.5) TeV-1 m;{-2} s;{-1} for gamma=-1.47 (-2) in the gamma flux and 0.4(6.1) TeV-1 m;{-2} s;{-1} for gamma=-1.47 (-2) in the high-energy neutrino flux. 相似文献
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The very broad M45?N23N45 (3d-1 → 4p-14d-1) Auger spectra for metals in the range Pd to Te arise from complete breakdown of the one-electron picture of the final state double vacancy due to 4p-14d-1 ? 4d-3?f giant Coster-Kronig fluctuation and decay processes. This is an example of atomic-like effects giving rise to level shifts and broadening which are large in comparison with typical widths of d-bands in solids. The 4p-14d-1 two-hole spectral function can be approximated by a 4p-1 single-hole spectral function perturbed by a static, sharp 4d-1 hole. The resulting Auger line-shapes are different from single-hole 4p-1 line-shapes from XPS and XES. Analogous effects also occur for double vacancies involving one or two 4s-holes. 相似文献