2CALIS doubling the sensitivity of CALIS for calibration of the rf field strength for indirectly observed nuclei

A new set of pulse sequences, 2CALIS, that exhibit double sensitivity of the recent CALIS pulse sequences for accurate calibration of the rf field strength for an indirectly observed spin is introduced. The sensitivity gain is a result of not forming heteronuclear coherence transfer gradient echoes although they are excellent for artifact suppression. It is, however, demonstrated that the scheme in 2CALIS for suppression of non (13)C-attached proton magnetization is adequate for calibration of the (13)C rf field strength even on natural abundance samples. A 2CALIS version with Watergate applicable to biomolecules in aqueous solution is also presented and demonstrated both in (13)C natural abundance and on a (13)C, (15)N enriched protein sample.     

辐射定标的新型参考光源技术

参考光源是辐射定标系统中的关键设备之一。近年来不同光谱分辨率、不同工作方式光电探测器的发展,需要参考光源在具备稳定性、均匀性等基本特性的同时,能够实现光谱匹配、大动态范围调节和宽波段精细扫描等新的功能。结合以LED为发光单元的可调光谱参考光源和利用宽调谐激光器的单色面光源技术,介绍了新型参考光源的设计、主要性能和部分前期的应用效果。新型参考光源可以与近年发展起来的基于探测器的标准传递技术相结合,在保障和提高绝对定标精度的同时,满足特定的定标技术要求。     

多角度偏振遥感相机DPC在轨偏振定标

为了做好卫星数据应用的技术储备,多角度偏振遥感相机DPC航空预研版已经研制成功并完成了航空飞行实验. DPC相机用于获取地气系统反射的偏振、多角度的太阳辐射信息,其地气物理参数反演依赖于定标的精度. 偏振相机的辐射定标包括强度和偏振两个方面. 本文研究偏振遥感相机的偏振参数的在轨定标原理与方法. 基于偏振遥感相机的设计原理,以相机的偏振辐射模型为基础,探索偏振定标的原理和方法. 使用DPC航空遥感实验数据,初步实现了在轨偏振定标并对定标结果进行了分析. 为将来我国自主星载偏振遥感数据处理和在轨偏振定标提供 关键词： 偏振定标 遥感 在轨定标 DPC     

A camera calibration method for large field optical measurement

A camera calibration method is presented for large field optical measurement, where the camera is close to the ground and the control points can only be located close to the ground, too. In such conditions, the camera's optical center and the control points are approximately coplanar. Only a single image of these control points captured by the camera in measurement state is used in the method. Neither to distribute the control points in space rationally nor to calibrate the camera's intrinsic parameters in laboratory in advance is needed. By the presented method, the camera's principal point position, focal length, radial and transverse tangency lens distortion coefficients, and the camera's position and attitude parameters can be estimated precisely. Then the calibration results can be used for precise large field optical measurement in the conditions that the camera's longitudinal tangency lens distortion can be neglected or the objects’ movement field is close to the ground, which is usually factual in practical applications. The presented camera calibration method has been successfully used in applications, such as automatic landing of UAV (Unmanned Aerial Vehicle) based on optical measurement guidance, to calibrate the cameras precisely.     

标校经纬仪航向标定修正方法

为了准确有效地完成经纬仪航向标定,本文根据标校经纬仪坞内航向标校原理,分析了各单项误差对航向标定的影响,建立了照准差和定向误差同时影响下的航向标定修正模型,给出了具体的修正方法。实验及检测结果表明,用正倒镜法测得的定向误差数值等于定向误差与照准差的差值。文章验证了修正方法的正确性和有效性,规范了坞内航向标定方法,为测量船完成测量任务奠定了基础。     

标校经纬仪航向标定修正方法(英文)

为了准确有效地完成经纬仪航向标定,本文根据标校经纬仪坞内航向标校原理,分析了各单项误差对航向标定的影响,建立了照准差和定向误差同时影响下的航向标定修正模型,给出了具体的修正方法。实验及检测结果表明,用正倒镜法测得的定向误差数值等于定向误差与照准差的差值。文章验证了修正方法的正确性和有效性,规范了坞内航向标定方法,为测量船完成测量任务奠定了基础。     

HLS注入段束流位置探头定标电场的拟合和误差计算

 描述了束流位置探测器(BPM)探头定标、定标电场的拟合和误差计算。该定标系统采用了具有调节精度为10μm垂直放置真空管道的天线模拟定标装置和分辨率高达1μm外差式、窄带频域信号处理电子学线路。并推导出针对合肥光源（HLS）定标系统条件下的电场拟合函数及相关的BPM-Mapping图和误差计算结果,较精确地计算出该高精度定标系统误差。     

Fast calibration methods using cosmic rays for a neutron detection array

An overall irradiation and calibration technique was introduced and applied to a test scintillation detector array. An integral conversion method was used to reduce the nonlinearity of the time difference spectrum, and to improve the position determination especially for positions close to the two ends of a long scintillation bar. An overall position resolution of about 3.0 cm (FWHM) was extracted from the residual analysis method and verified by a direct measurement. Energy calibration was also realized by selecting cosmic rays at different incident angles. The bulk light attenuation lengths for the four test bars were also determined. It is demonstrated that these methods are especially efficient for calibrating large and complex detector arrays.     

HgCdTe-IRFPA成像器件光谱响应率标定方法比较与误差分析

红外焦平面成像器件的光谱响应率是天基红外遥感的基本物理指标。为了准确应用该项参数去除器件在制造工艺中的不均匀性对产品质量的影响，必须在系统使用之前对其重新标定，获取真实值。总结了目前较为普遍的IRPFA产品光谱响应率标定方法，通过比较选择标准代替法对产品进行标定。根据所得到测量数据，分析了其可能存在的误差，总结了在对IRPFA产品进行标定时应注意的问题。同时提出了一种调整积分时间的方法，以弥补有些波段标定黑体辐射功率过低带来误差过大的缺陷。     

Effect of field of view on the accuracy of camera calibration

A long focal length lens can improve the spatial resolution and capture more detailed information, so it has been considered for three-dimensional (3D) vision reconstruction. However, the field of view (FOV) will narrow with a long focal length lens. It is a general concept that it is extremely difficult to achieve high-accuracy calibration of a narrow FOV camera because of paraxial imaging. In this paper an in-depth study on this issue is conducted from the aspect of perspective deformation. First, the perspective deformation of a point is divided into three parts. Then, the noise immunity of each part under different FOVs is discussed to reveal the root cause of the difficulty in the calibration of narrow FOV cameras. It is found that the calibration accuracy could be generally maintained at the same level if the image noise is inversely proportional to the focal length. Simulations verify the correctness of the inferences of this study that are hoped to be helpful in overcoming this disadvantage of narrow FOV cameras.     

New methods for studying the interaction of unstable mesons with nuclei

Recent results of the GRAAL experiment and simulation of meson photoproduction on nuclei are presented.     

一种显示器颜色特性的反向查找新方法

根据实验的数据建立了CRT的设备颜色空间(RGB空间)与标准颜色空间(CIELAB空间)之间的颜色特性转换模型。通过分析大量的实验测量数据,以改进的三维查找表形式建立了RGB和L*a*b*之间的正逆转换关系。其中正向查找表的建立是按照三维线性的插值方法,逆向查找表的建立则利用一种插值和迭代相结合的新方法,使L*a*b*查找到较为准确的RGB值。通过用标准图像的的随机误差检验,其转换的平均色差ΔE为0.9286色差单位。     

Increasing the sensitivity of 2D high-resolution NMR methods applied to quadrupolar nuclei

Gan and Kwak recently proposed a soft-pulse added mixing (SPAM) idea in the classical two-pulse multiple-quantum magic-angle spinning scheme. In the SPAM method, a soft pi/2 pulse is added after the second hard-pulse (conversion pulse) and all coherence orders in between them are constructively used to obtain the signal. We, here, further extend this idea to distributed samples where the signal mainly results from echo pathways and that from anti-echo pathways dies out after a few t1 increments. We show that, with a combination of SPAM and collection of fewer anti-echoes, an enhancement of the signal to noise ratio by a factor of ca. 3 may be obtained over the z-filtered version. This may prove to be useful even for samples with long T2' relaxation times.     

Absolute photon energy calibration for the BESIH EMC

The absolute energy calibration with photons from π~0's for the BESIII EMC is discussed. Using 3 million hadronic events, the preliminary results are presented. Precision of about 1% in the photon energy measurement is obtained from crossing check using photons in ψ(2S) →γχ_(c1,2)(1.P).     

Temperature calibration for high-temperature MAS NMR to 913 K: 63Cu MAS NMR of CuBr and CuI, and 23Na MAS NMR of NaNbO3

The solid-state phase transitions of CuBr, CuI and NaNbO₃ can be readily observed using ⁶³Cu and ²³Na high-temperature magic-angle spinning nuclear magnetic resonance spectroscopy. Temperature has large, linear effects on the peak maximum of ⁶³Cu in each solid phase of CuBr and CuI, and there is large jump in shift across each phase transition. The ²³Na MAS NMR peak intensities and the line widths in NaNbO₃ also clearly show its high-temperature transition to the cubic phase. These data can be used to calibrate high-temperature MAS NMR probes up to 913 K, which is two hundred degrees higher than the commonly-used temperature calibration based on the chemical shift of ²⁰⁷Pb in Pb(NO₃)₂.     

Excitation curve calibration for the SSRF magnet system

The needed electrical current for the magnet working under different energy loads can be easily calculated once the right relation between the magnet and the electrical current has been found. Therefore the excitation curve calibration for the magnet system is important to the SSRF. The measuring method on the magnet and the result of the excitation curve calibration are presented. The application of the excitation curve calibration for the bending magnet is given, and it is proved that the COD (Closed Orbit Distortion) and the working point of the storage ring are greatly affected by the current of the bending magnet.     

稻米色氨酸含量近红外反射光谱全局和局部飞速定标技术研究

色氨酸是人类一种必需氨基酸,也是稻米中一种重要的限制性氨基酸。从4年份1256份材料中选择出272份有代表性的样品,采用碱水解-分光光度法测定了其色氨酸含量。比较不同定标方法的预测结果发现,运用改良的偏最小二乘法(modified partial least square,MPLS)的全局(Global)定标方法和局部(Lo-cal)飞速定标方法的预测效果较佳,基于精米粉光谱建立的方程的预测标准误差均为0.007%,外部验证决定系数分别为87.1%和87.4%,可用于定量分析;而基于糙米光谱建立的定标方程的预测效果略差,但仍具有良好的预测能力。研究结果表明,近红外光谱技术可作为水稻育种中间材料的快速筛选和食品工业中稻米原料的品质监控手段。     

射频场照射下多自旋体系弛豫的理论计算

根据Liouville-von Neumann方程，对射频场照射下多自旋体系的弛豫进行了理论描述，并用WBR理论推导出了体系的弛豫方程组，给出了各类弛豫速率的理论计算公式.在此基础上，编制了弛豫方程组数值解的计算程序，分别用此程序和Bloch方程计算了双自旋体系在不同情况下的稳态解，并对计算结果进行了简要的分析和讨论. 关键词： 核磁共振 弛豫 射频场 多自旋体系     

Excitation curve calibration for the SSRF magnet system

The needed electrical current for the magnet working under different energy loads can be easily calculated once the right relation between the magnet and the electrical current has been found. Therefore the excitation curve calibration for the magnet system is important to the SSRF. The measuring method on the magnet and the result of the excitation curve calibration are presented. The application of the excitation curve calibration for the bending magnet is given, and it is proved that the COD （Closed Orbit Distortion） and the working point of the storage ring are greatly affected by the current of the bending magnet.     

水流吸收型高能激光能量计溯源方法及其溯源体系研究

提出了一种利用电加热丝作为校准源的高能激光能量计校准方法,将水流从吸收腔前端导入至加热容器,在加热后流入吸收腔。通过精确计量水流吸收的热能并与能量计测量结果进行比较,达到对高能激光能量计校准的目的。研究表明校准系统的热交换模型与吸收腔内的热交换模型一致,均经历了储能和功率平衡两个阶段。水流及相变气体的散射效应对测量结果的影响较小,经过修正后可以忽略其影响。通过深入分析各个环节的测量不确定度表明,残留能量和流量变化对测量不确定度的影响最显著,增加水箱的容积可以有效降低残留能量对测量不确定度的影响。在对各个环节的影响修正后估算出系统的测量不确定度约为4.8%(k=2),被校高能激光能量计校准后的测量结果与其他类型的参考高能激光能量计进行比对,两者具有很好的一致性,修正因子仅为1.006,标准偏差为1.4%。