共查询到20条相似文献,搜索用时 156 毫秒
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在物理实验中,由于仪器本身不够精密或实验原理不完善或实验方法粗略所造成的实验误差叫做系统误差.同一实验的系统误差总是偏大或者偏小,即系统误差具有一定的方向性.判定系统误差的方向性不同于求系统误差的大小,其方法具有一定的灵活性,值得总结与推广.本文介绍几种判定物理实验系统误差方向性的常用方法。 相似文献
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光电直读光谱分析中的空白校正法及应用 总被引:4,自引:0,他引:4
运用空白校正校正在光电直读光谱分析中因试样类型,组织结构,成分含量,仪器波动和基体效应等因素造成的系统误差,本文对空白校正的方法原理,操作要点,实现过程及应用也作了介绍。 相似文献
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光子晶体光纤弯曲损耗特性研究 总被引:2,自引:3,他引:2
对光子晶体光纤的损耗特性进行了分析,并在实验上对两种典型的光子带隙型和全内反射型光子晶体光纤进行了研究.分别对两种不同结构的光子晶体光纤在弯曲半径2~15 mm范围内的损耗进行了测量.与传统光纤损耗实验结果的对比表明,两种光子晶体光纤的弯曲损耗均不明显,具有很强的抗弯曲损耗能力.实验也证实了光子晶体光纤弯曲损耗存在临界弯曲半径,在大于临界半径的情况下,几乎没有弯曲损耗.从结构上分析并证明光子晶体光纤弯曲损耗随填充比(d/Λ)的增加而减小,填充比越高弯曲损耗越小. 相似文献
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光子晶体光纤的弯曲损耗振荡特性分析 总被引:2,自引:1,他引:1
综合运用弯曲光纤的等效直光纤模型、全矢量频域有限差分法及各向异性完全匹配层吸收边界,计算了两种类型(折射率引导型和带隙型)光子晶体光纤(PCF)的弯曲损耗.通过数值模拟弯曲损耗随弯曲半径的变化关系,证实了两种光子晶体光纤均具有弯曲损耗振荡特性.进而分析了两种光子晶体光纤弯曲损耗振荡的产生机理并给出了与损耗峰对应的包层模式.结果表明,振荡的产生源于基模与包层模式的耦合,其中,折射率引导型光子晶体光纤的弯曲损耗振荡机理类似于传统双包层光纤,带隙型光子晶体光纤弯曲损耗振荡的产生则是两种不同类型的包层模式共同作用的结果. 相似文献
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根据双线法测量横向阻抗的原理,从理论和模拟计算两方面对双线间距、线径因素造成的系统误差进行讨论。给出谐振腔近似下双线法测量横向阻抗的等效电路,通过此等效电路对双线间距、线径因素造成的系统误差进行讨论。通过模拟计算的方法分析了双线法测量类腔体TM110模式横向阻抗时,不同双线间距、不同线径带来的系统误差,模拟计算的结果与等效电路结果分析得到的定性结果一致。模拟计算分析表明,对于管道半径为50 mm的类腔体结构,线径小于6 mm及双线距离小于50 mm时,双线间距及线径引入的横向阻抗系统误差小于8%。 相似文献
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去年(1979)12月17日的物理快报发表了用弯曲晶体控制带电粒子的轨道的第一个实验结果[1].一个由苏联、波兰和美国合作的实验组在杜布纳联合核子研究所高能实验室,利用84GeV的质子束入射到弯曲的晶体上,发现出射的质子束偏转了达 26mrad.这相当于偏转曲率半径为38cm,等价于240 MV/cm的电场或0.81MGs的磁场. 弯曲晶体的偏转效应,是指进入晶体并在临界角内被俘获到沟道轨道的粒子可以沿着晶体的面的曲率运动,直到晶体的弯曲半径等于临界半径为止.这是因为在弯曲晶体中粒子的运动被平均有效势所导向,这种势包含着与弯曲半径有关的离心成份的… 相似文献
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利用扫描电子显微镜(SEM)和原子力显微镜(AFM)等表征手段,研究了聚对苯二甲酸乙二醇酯-双酚A型聚碳酸酯(PET-PC)共混物的高压结晶样品。研究发现共混体系中存在具备不同形态特征的伸直链晶体,其中包括楔形晶体、弯曲晶体以及楔形弯曲晶体。通过对这些晶体的形态观察,揭示出体系中大尺寸聚酯伸直链单晶体的增厚生长首先要经历形成折叠链晶核的成核阶段,然后才是在酯交换反应和链滑移扩散两种机制共同作用下的等温增厚的链伸展过程。有助于深入理解PET-PC共混物中伸直链单晶体生长过程的本质因素,以便在类似聚合物体系中合成大尺寸的同类晶体。 相似文献
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Liangjie Feng Le Kang Zhongliang Li Feixun Zhao Chaoyin Xu 《Journal of synchrotron radiation》2008,15(2):140-143
A scanning dynamically focusing sagittal X‐ray monochromator accepting 3 mrad × 0.1 mrad from a 6 T wiggler has been designed for XAFS measurements. In the energy range 4.1–12.4 keV, the slope error of the second cylindrical crystal caused by anticlastic bending must be less than 1/5 of the Darwin width of the crystal or the photon flux will decrease drastically. Two methods to minimize the anticlastic bending are proposed. Thin crystals with stiffening ribs and thin crystals with an aspect ratio equal to the `golden value' are evaluated by finite‐element analysis and by long‐trace‐profiler characterization. Both approaches are satisfactory, but the `golden value' approach is preferred in this case for the second crystal of the new monochromator not only because it is easy to manufacture but also because the surface is smoother than the ribbed crystal. 相似文献
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D.S. Khatri 《Physics letters. A》1976,57(3):285-286
Various studies have shown that the mean square amplitude of atoms on the surface of a crystal is almost twice that in the bulk. We believe that the results obtained by Kothari, using simple physical arguments for surface vibrations, were in error. We have also shown that the results could be explained by taking the contribution of bending waves in addition to surface vibrations for a 2-dimensional crystal. 相似文献
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We propose a new subdivision technique directly subdividing the grating stripe by using complementary metal-oxide semiconductor (CMOS) microscopic imaging system combined with image processing. The corresponding optical system, subdivision principle, and image processing methods are illuminated. The relations of systemic resolution to subdivision number, grating period, magnifying power and tilt angle are theoretically discussed and experimentally checked on the Abbe comparator. The measurement precision for displacement of the proposed subdivision system is tested in the range of 5 mm and the maximum displacement error is less than 0.4μm. The factors contributing to the systemic error are also discussed. 相似文献
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The features of the intensity distribution over the exit surface of a uniformly bent crystal have been investigated in reflection
geometry. Experiments have been performed using thin-layer heterostructures Si(1−x)Ge
x
/Si. For heterosystems, internal stresses induced in the film and substrate lead to an elastic bending of the whole system.
The section topographs exhibit deformation interference fringes. It is important that the contrast of this interference pattern
is almost one order of magnitude higher than the contrast in the case of Bragg scattering in a perfect crystal. The observed
interference pattern depends on the radius of bending of the crystal. As the bending radius increases, all maxima shift toward
the basic Bragg peak. Correspondingly, all distances between the interference fringes decrease. It has been shown that the
positions of intensity maxima do not depend on the sign of the crystal bending. For a negative sign of the radius of the crystal
bending (positive strain gradient), the integrated intensity increases. The results of the numerical simulation of the diffraction
images agree well with the experimental topographs. A comparison of the numerical simulation of the interference pattern with
the experimental topographs makes it possible to exactly determine the radius of the crystal bending (4%). The formulas describing
the positions of interference maxima as a function of the bending radius of the sample have been obtained using the results
of the numerical simulation of the experiment. 相似文献
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本文介绍了CRI-100I晶体光轴定向仪的工作原理、仪器设计、误差源及精度分析,同时也介绍了该仪器的应用。CRI-100I晶体光轴定向仪结构简单、工件装夹方便、定向精度高。当采用激光锥光干涉图时,对比度好、观察和读数方便。测出的数据经微机测角误差修正软件的处理,可以使测量值达到更高的精度。 相似文献