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41.
X射线显微术   总被引:4,自引:0,他引:4  
徐向东  付绍军  张允武 《物理》1999,28(3):181-186
综述了X射线显微术的基本原理,成像模式和技术及其在生命科学,材料科学等方面应用的新进展,同时简述了X线射显微术应用过程中应注意的几个问题。  相似文献   
42.
We suggested a new non-mechanical angular multiplexed holographic memory system using a moving window, which was fabricated by controlling the pixels of a liquid crystal display (LCD) electronically. If we use light passed through the window left and right, and up and down, each window makes a reference wave with a different incidence angle and we can store angular-multiplexed holograms. The feasibility of the proposed method was demonstrated through optical experiments and its crosstalk noise analysis was also presented.  相似文献   
43.
44.
金刚石近红外增透滤光保护窗口的制备及应用   总被引:2,自引:0,他引:2  
报道金刚石近红外增透滤光保护窗口的研制及其在工业中的应用。采用热灯丝化学气相沉积方法成功地制备出金刚石近红外增透滤光保护窗口,其工作波长为1.3 ̄1.8μm,具有良好的光学透过性和优良的物理化学性质。该窗口已在上海宝钢获得成功应用。  相似文献   
45.
The traditional sequential pattern mining method is carried out considering the whole time period and often ignores the sequential patterns that only occur in local time windows, as well as possible periodicity. Therefore, in order to overcome the limitations of traditional methods, this paper proposes status set sequential pattern mining with time windows (SSPMTW). In contrast to traditional methods, the item status is considered, and time windows, minimum confidence, minimum coverage, minimum factor set ratios and other constraints are added to mine more valuable rules in local time windows. The periodicity of these rules is also analyzed. According to the proposed method, this paper improves the Apriori algorithm, proposes the TW-Apriori algorithm, and explains the basic idea of the algorithm. Then, the feasibility, validity and efficiency of the proposed method and algorithm are verified by small-scale and large-scale examples. In a large-scale numerical example solution, the influence of various constraints on the mining results is analyzed. Finally, the solution results of SSPM and SSPMTW are compared and analyzed, and it is suggested that SSPMTW can excavate the laws existing in local time windows and analyze the periodicity of the laws, which solves the problem of SSPM ignoring the laws existing in local time windows and overcomes the limitations of traditional sequential pattern mining algorithms. In addition, the rules mined by SSPMTW reduce the entropy of the system.  相似文献   
46.
《Electrophoresis》2017,38(3-4):452-459
A new detector, silvering detection window and in‐capillary optical fiber light‐emitting diode‐induced fluorescence detector (SDW‐ICOF‐LED‐IFD), is introduced for capillary electrophoresis (CE). The strategy of the work was that half surface of the detection window was coated with silver mirror, which could reflect the undetected fluorescence to the photomultiplier tube to be detected, consequently enhancing the detection sensitivity. Sulfonamides (SAs) are important antibiotics that achieved great applications in many fields. However, they pose a serious threat on the environment and human health when they enter into the environment. The SDW‐ICOF‐LED‐IFD‐CE system was used to determine fluorescein isothiocyanate (FITC)‐labeled sulfadoxine (SDM), sulfaguanidine (SGD) and sulfamonomethoxine sodium (SMM‐Na) in environmental water. The detection results obtained by the SDW‐ICOF‐LED‐IFD‐CE system were compared to those acquired by the CE with in‐capillary optical fiber light‐emitting diode‐induced fluorescence detection (ICOF‐LED‐IFD‐CE). The limits of detection (LODs) of SDW‐ICOF‐LED‐IFD‐CE and ICOF‐LED‐IFD‐CE were 1.0–2.0 nM and 2.5–7.7 nM (S/N = 3), respectively. The intraday (n = 6) and interday (n = 6) precision of migration time and corresponding peak area for both types of CE were all less than 0.86% and 3.68%, respectively. The accuracy of the proposed method was judged by employing standard addition method, and recoveries obtained were in the range of 92.5–102.9%. The results indicated that the sensitivity of the SDW‐ICOF‐LED‐IFD‐CE system was improved, and that its reproducibility and accuracy were satisfactory. It was successfully applied to analyze SAs in environmental water.  相似文献   
47.
We consider an incompressible neo-Hookean elastic solid sliding on a rigid surface under the influence of Coulomb friction. It is shown that ill-posedness at the boundary due to failure of Agmon's condition can occur. If the friction coefficient is greater than one, this is the case even in the limit of linear elasticity. The effect of a dependence of the friction force on the sliding velocity is also considered.  相似文献   
48.
In spite of its low isotopic abundance in methane (about 5×10−4), CH3D contributes greatly to the very weak absorption in the 1.58 μm methane transparency window. This methane window deserves to be characterized in details because it is important for planetary applications in particular for Titan and the giant planets. In this work, we recorded the CH3D spectrum by high sensitivity differential absorption spectroscopy (αmin≈5×10−8 cm−1) both at room temperature and at 81 K. A list of more than 9000 lines was constructed from the 81 K spectrum for the 6099–6530 cm−1 region. In order to get the temperature dependence of the line intensities, the low energy values have to be determined. The rovibrational assignments available in the literature provide low energy values for about 380 strong transitions of the region. This is insufficient to characterize the temperature dependence of the CH3D absorption between 6200 and 6400 cm−1. In this interval, a list of 5500 lines was constructed from the room temperature spectrum. The empirical energy values of the transitions were derived from the ratio of the intensities at 81 K and 294 K. The exact and empirical lower state energies included in the final line lists provided as Supplementary Material, allow for accounting for the temperature dependence of the CH3D spectrum in the entire 6099–6530 cm−1 region.Our measurements have been compared to the spectroscopic parameters and assignments available in the literature in particular those adopted in the HITRAN database. Improvements and corrections are proposed for the wavenumber calibration and for some lower state energies.  相似文献   
49.
常军  张正慧  王蕊瑞 《物理学报》2011,60(3):34218-034218
使用新型的特殊整流罩窗口可以明显地提升飞行器的空气动力学性能,但由于这种共形窗口光学表面的复杂性,传统的非球面检测技术已经较难满足要求.本文提出了一种新型子孔径拼接检测技术,在建立新的检测原理基础上,还重点介绍了这种检测方法的设计.同时基于补偿法的原理,文中还针对一个口径70 mm的共形窗口,设计了相应的特殊补偿器,其最终剩余波像差(RMS)为0.0515λ(λ=632.8 nm),可以满足实际使用要求. 关键词: 共形窗口 共形检测 子孔径拼接检测 补偿器  相似文献   
50.
激光脉冲参数对冲击点火的影响   总被引:1,自引:0,他引:1       下载免费PDF全文
袁强  胡东霞  张鑫  赵军普  胡思得  黄文会  魏晓峰 《物理学报》2011,60(4):45207-045207
针对激光脉冲参数对冲击点火的影响进行理论分析和数值模拟.首先从冲击波的产生和碰撞过程出发,理论分析冲击脉冲峰值功率、脉宽和上升沿时间对点火的影响;然后通过数值模拟,以点火时间窗口作为评价标准,验证理论分析结果.研究表明:冲击脉冲峰值功率是点火成败的关键因素之一,脉冲宽度则需达到百皮秒以提供足够的点火能量,上升沿时间在小于600 ps的情况下不会对点火造成明显影响. 关键词: 冲击点火 激光冲击脉冲 点火时间窗口  相似文献   
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