升级的合肥光源闭轨测量系统及其应用

 描述了合肥同步辐射光源二期工程中，电子储存环升级的闭轨测量系统及其在设备研制中的应用。介绍了性能稳定可靠的Bergoz束流位置监测电子学信号处理器。升级后的闭轨测量系统中处理电子学电路的束流位置分辨率可达1μm，系统误差小于10μm。整个测试系统的分辨率小于3μm。利用该高精度闭轨测量系统和基于束流准直系统完成了束流准直四极铁磁中心的测量，并和控制系统完成了储存环全环闭轨反馈校正试验。一个完整的束流位置监测系统已投入了在线运行，保障了为用户提供高稳定高品质的光源。     

准直物镜在变焦距镜头杂散光系数测试中的作用和影响分析

在对变焦距光学镜头进行杂散光系数测试的过程中,需要了解各测试环节的作用及对测量结果的影响。讨论了准直物镜使用与否对杂散光系数测量结果的影响。通过对杂散光形成机理的分析,将杂散光来源分为视场内与视场外两种,阐述不同来源杂散光的不同特点及这两种杂散光通过准直物镜后的状态。用两个参数不同的变焦距光学镜头在有无准直物镜两种情况下杂散光系数的测量结果,说明准直物镜在杂光测试中的作用。对于视场外入射光束形成的杂散光,准直物镜的使用与否对其测量结果影响巨大,而对视场内入射光束形成的杂散光影响很小,测量时可以利用准直物镜来判断光学镜头杂散光的来源。同时通过实验说明入射光线在准直物镜间的多次反射形成的杂散光约为1%,它可作为系统误差从测量结果中剔除。     

NIM锶原子钟用准直器的初步计算

在锶原子钟的研制过程中，为提高原子柬的准直效率，需要在准直器圆面上加工出最大数量的给定直径的小孔。用小圆紧密排列逐层求算的计算方法，在直径D=3080μm的圆面积上获得小圆孔（d=200μm）个数的最大值，提高了原子柬准直器的准直性。     

如何判定物理实验系统误差的方向性

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。     

直线感应加速器机械轴精密对中方法

 介绍了大型直线感应加速器机械轴精密对中安装方法和工艺。直线感应加速器由多个组元连接而成，总长几十m。采用激光跟踪仪并配以全站仪、水准仪进行准直测量，再用专门设计的高精度调节机构调节，可使机械轴的准直达到较高的精度。分析了准直安装各步骤能达到的精度，研究了几十m长机械轴准直控制测量网的建立和理论坐标值的修正。     

振动线准直技术的原理和研究概述

振动线准直技术是一种通过直接测量空间磁场分布情况来进行磁铁设备准直的方法,其原理完全不同于目前国内正在使用的基于磁铁机械结构进行准直的方法。振动线方法具有很高的准直精度和灵敏性,可以用于单个磁铁磁中心测量、磁铁准直标定和多块磁铁磁中心准直等。主要介绍了振动线准直技术的原理、起源和国际上的应用研究概况。     

高能质子照相中基于角度准直器设计的理论研究

角度准直器在高能质子照相中有着重要作用,既可以利用准直器提高图像对比度,又能通过二次成像实现材料诊断及密度重建,因此减小通过准直器后通量值的误差具有重要意义.本文通过理论分析,提出了一种高能质子照相中准直器设计的方法,通过Geant4程序建立了1.6 GeV的质子成像系统,该系统分别使用理想准直器、拉伸型准直器和利用该方法设计的准直器,并对比通过客体后的通量分布.结果表明,在使用理想准直器和该方法设计的角度准直器时,二者得到的客体的通量分布符合较好,而使用拉伸型准直器时,与使用理想准直器得到的结果相差较大.因此利用理想准直器方法设计的准直器可以很好地减小通量误差.     

（n,2n）反应实验研究中的中子准直器设计

用3He球形4中子探测器，通过直接反应法可以对核素的（n,2n）反应截面进行测量。在此类实验中，要求对中子束进行很好的准直。好的准直器设计要求能够提高样品处的中子注量率的均匀性，同时保证中子束流边缘处的下降幅度，能够降低低能中子所占份额。本工作采用FLUKA和MCNPX对圆柱形准直器、单锥形准直器及三种不同斜率的双锥形准直器对中子注量率的均匀性和低能中子所占份额进行了对比研究，结果表明，低斜率的双锥形准直器可以满足实验对这两方面的要求。同时，在有样品和无样品两种条件下，对探测系统经由这五种不同准直器准直后的中子束流的响应做了对比，结果显示，经过低斜率的双锥形准直器准直的中子束流，探测系统在有样品时表现为较高的计数率，在无样品时表现为较低的本底。除此之外，对准直器出口处的斜率对准直效果的影响也做了比较。最终中子准直器选用为这种低斜率的双锥形准直器，材料选用为紫铜、不锈钢、聚乙烯和铅。准直孔开口处直径为2.64 cm，长度为137 cm，经准直后样品处的中子束斑直径为3.2 cm。     

光路自动准直快速调整数学模型研究

推演了用于计算机快速调整的巨型激光器光路自动准直控制数学模型，分析了ICF准直光路的光学特性及光路调整特点，据此求解出了准直控制的输入偏差量和输出控制量之间的数学模型.该模型在某大型激光装置的光路自动准直中得以实际应用，八路主放大级1～2程光路的准直时间＜3 min，3～4程光路的准直时间＜8 min，主放大级输出光束近场准直准确度优于0.3%，远场指向的准确度优于0.3″ RMS（均方根准确度）.     

基于图像边沿特征的强激光腔镜准直处理方法

 激光束光路自动准直系统用于高功率激光装置光束精密准直。基于某激光原型装置总体对腔镜准直调整流程，针对高功率激光系统腔镜准直过程光斑图像，仿真处理并定量分析了光斑边缘特征;结合腔镜准直监测单元光传输分析，使用激光光斑边缘不同部分曲率的相似性和光斑圆形度实现了对腔镜调节的量化评估。在腔镜准直结束时圆形度指标为12.222；边缘相似度达到99.62%。     

Analogue correction method of errors and its application to numerical weather prediction

In this paper, an analogue correction method of errors （ACE） based on a complicated atmospheric model is further developed and applied to numerical weather prediction （NWP）. The analysis shows that the ACE can effectively reduce model errors by combining the statistical analogue method with the dynamical model together in order that the information of plenty of historical data is utilized in the current complicated NWP model, Furthermore, in the ACE, the differences of the similarities between different historical analogues and the current initial state are considered as the weights for estimating model errors. The results of daily, decad and monthly prediction experiments on a complicated T63 atmospheric model show that the performance of the ACE by correcting model errors based on the estimation of the errors of 4 historical analogue predictions is not only better than that of the scheme of only introducing the correction of the errors of every single analogue prediction, but is also better than that of the T63 model.     

激光陀螺捷联惯导的动基座标定

从实际工程应用和维护的角度出发,提出了一种针对舰船在系泊或锚泊条件下激光陀螺捷联惯导安装误差的在线标定方法.该方法依据捷联惯导系统误差方程的基本原理,将标度因数误差、安装误差角、陀螺加速度计常值漂移以及系统基本误差项作为状态变量,用外部提供的高精度经纬度作为观测量,运用Kalman滤波技术估计出激光陀螺和加速度计的常值...     

光学薄膜鲁棒设计中膜系误差灵敏度控制

提出了一种基于膜系误差灵敏度控制的鲁棒膜系设计方法,建立了鲁棒膜系设计评价函数在膜层参数误差统计分布下的解析表达式,避免统计样本数目有限性造成的样本均值与总体期望的误差,以及过大数目样本造成的长的计算时间消耗,并通过宽带增透膜、中性分光膜和线性透射率滤光片等多种薄膜的鲁棒设计实验证实了其在膜层参数误差控制上的效果。结果表明:该新型鲁棒膜系设计方法具有内在的快速算法特性,其设计膜系对镀膜中的膜厚监控误差不敏感,对于高质量薄膜的重复制备和批量成品率的提高具有实用价值。     

Analysis of Phase Measurement Errors in Electro-Optic Holography

This paper presents the results of an error analysis in electro-optics holography. These errors include phase measurement errors due to the linear phase shifter errors in static electro-optic holography, and phase measurement errors due to the errors in the vibrating bias amplitude and phase in dynamic electro-optic holography. Through the error analysis, we found that the phase shifting errors in static electro-optic holography are twice as large as those in the conventional 4-bucket phase shifting algorithm, and the phase shifting errors in dynamic electro-optic holography are similar to those in the 4-bucket phase shifting algorithm.     

Imaging errors in arrayed waveguide gratings

A detailed assessment of imaging errors in arrayed waveguide gratings (AWG) is presented, focussing on possible design related imaging errors as well as on typical imaging errors mediated by the fabrication process. From a design point of view, special interest is drawn to the effect of coupling within the array of grating waveguides and to the impact of the paraxial approximation for the star couplers which is commonly used in the design of AWGs. Both become important design issues affecting the performance of AWG devices when moving to high numbers of narrowly spaced channels. For the technology related imaging errors we focus on one side on the impact of almost uncorrelated phase errors at high spatial frequencies. They can typically be attributed to fluctuations in the index profile and waveguide dimensions in the grating region. On the other side correlated long range phase errors are treated which occur in the grating region as well as within the star couplers and which are typical for stress induced index changes in silica-on-silicon waveguides. It is shown that only modelling tools which include all types of the above imaging effects can provide reliable boundary conditions for a comprehensive design of high end AWG concerning spectral shape and chromatic dispersion.     

角锥棱镜激光谐振腔的基本特性

 分析了角锥棱镜对光束的相位变换作用，带二面角误差的角锥棱镜可等效于6块光楔的组合，其楔角的大小和方向由二面角误差决定。对在腔内往返传输的光线在镜面上的位置进行了分析，结果表明：3个二面角误差相同且不为零的角锥棱镜构成的谐振腔为约束非稳腔。用Fox-Li迭代法数值模拟得到了不同棱镜二面角误差情况下的谐振模式。模拟结果表明：圆形镜腔情况下基本振荡模式接近于TEM₀₃模的拉盖尔高斯光束；当3个二面角误差不相同时，模式中各个区域的强度分布不对称。采用3个二面角误差基本接近且绝对值较小的棱镜可以提高光束质量。     

平场全息凹面光栅制作结构与使用结构之间误差补偿作用的数值模拟与实验验证

通过对优化计算出的平场全息凹面光栅制作结构(曝光记录结构)和使用结构(光谱仪分光结构)之间各个参数进行联合数值模拟,得出如下结论:在优化设计参数值附近一个较大范围的误差区域内,平场全息凹面光栅的制作结构参数误差和使用结构参数误差可以相互补偿,最终补偿的结果可以使光谱成像质量达到与原设计结构相当的水平,满足光谱仪器的使用要求。文章给出了数值模拟结果以及与其相符的实验验证结果。此补偿作用有利于降低平场全息凹面光栅制作中各个参数精度的调节难度,并且可以对实际使用过程中光谱仪器的设计和装调进行理论上的指导。     

二元光学元件衍射效率的逐层分析法研究

提出了一种有效的分析二元光学元件衍射效率的新方法－逐层分析法，并对四台阶二元器件，就蚀刻深度误差和横向对准误差对器件衍射效率的影响进行了详细的分析和讨论，证明了用该方法分析含有横向对准误差的二元光学元件的衍射效率非常简便有效。     

Analysis method of the effect of fabrication errors on a planar waveguide demultiplexer

The impact of fabrication errors on a planar waveguide demultiplexer is analyzed based on an analytical method. The explicit expression of the transfer function taking into account phase and amplitude errors is presented in order to analyze the loss and crosstalk of the demultiplexer caused by fabrication errors. A basic requirement for the demultiplexer with a certain crosstalk criterion can be easily obtained. Using an etched diffraction grating demultiplexer as an example, it is shown that the analytical results have a good agreement with results from a numerical method.     

A computational error-assessment of central finite-volume discretizations in large-eddy simulation using a Smagorinsky model

We present a framework for the computational assessment and comparison of large-eddy simulation methods. We apply this to large-eddy simulation of homogeneous isotropic decaying turbulence using a Smagorinsky subgrid model and investigate the combined effect of discretization and model errors at coarse subgrid resolutions. We compare four different central finite-volume methods. These discretization methods arise from the four possible combinations that can be made with a second-order and a fourth-order central scheme for either the convective and the viscous fluxes. By systematically varying the simulation resolution and the Smagorinsky coefficient, we determine parameter regions for which a desired number of flow properties is simultaneously predicted with approximately minimal error. We include both physics-based and mathematics-based error definitions, leading to different error-measures designed to emphasize either errors in large- or in small-scale flow properties. It is shown that the evaluation of simulations based on a single physics-based error may lead to inaccurate perceptions on quality. We demonstrate however that evaluations based on a range of errors yields robust conclusions on accuracy, both for physics-based and mathematics-based errors. Parameter regions where all considered errors are simultaneously near-optimal are referred to as ‘multi-objective optimal’ parameter regions. The effects of discretization errors are particularly important at marginal spatial resolution. Such resolutions reflect local simulation conditions that may also be found in parts of more complex flow simulations. Under these circumstances, the asymptotic error-behavior as expressed by the order of the spatial discretization is no longer characteristic for the total dynamic consequences of discretization errors. We find that the level of overall simulation errors for a second-order central discretization of both the convective and viscous fluxes (the ‘2–2’ method), and the fully fourth-order (‘4–4’) method, is equivalent in their respective ‘multi-objective optimal’ regions. Mixed order methods, i.e. the ‘2–4’ and ‘4–2’ combinations, yield errors which are considerably higher.