EVALUATION OF THE EFFECT OF WAVELENGTH POSITIONING ERRORS ON KALMAN FILTERING RESULTS IN INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

This work evaluates the effect of wavelength positioning errors in spectral scans on analytical results when the Kalman filtering technique is used for the correction of line interferences in inductively coupled plasma atomic emission spectrometry (ICP-AES). The results show that a positioning accuracy of 0.1 pm is required in order to obtain accurate and precise estimates for analyte concentrations. The positioning error in sample scans is more crucial than that in model scans. The relative bias in measured analyte concentration originating from a positioning error in a sample scan increases linearly with an increase in the magnitude of the error and the peak distance of the overlapping lines, but is inversely proportional to the signal-to-background ratio. By the use of an optimization procedure for the positions of scans with the innovations number as the criterion, the wavelength positioning error can be reduced and, correspondingly, the accuracy and precision of analytical results improved.

Precise determination of anomalous scattering factors of Ge by using X-ray resonant scattering

Variations of peak position of the rocking curve in the Bragg case are measured from a Ge thin crystal near the K-absorption edge. The variations are caused by a phase change of the real part of the atomic scattering factor. Based on the measurement, the values of the real part are determined with an accuracy of better than 1%. The values are the most reliable ones among those reported values so far as they are directly determined from the normal atomic scattering factors.

A novel method for positioning of InAs islands on GaAs(110)

A novel method for positioning of InAs islands on GaAs (110) by cleaved edge overgrowth is reported. The first growth sample contains strained InxGa1-xAs/GaAs superlattice (SL) of varying indium fraction, which acts as a strain nanopattern for the cleaved-edge overgrowth. Atoms incident on the cleaved edge will preferentially migrate to InGaAs regions where favorable bonding sites are available. By this method InAs island chains with lateral periodicity defined by the thickness of InGaAs and GaAs of SL have been realized by molecular beam epitaxy (MBE). They are observed by means of atomic force microscopy (AFM). The strain nanopattern's effect is studied by the different indium fraction of SL and MBE growth conditions. (c) 2005 Elsevier B.V. All rights reserved.

Design and Fabrication of Low-microwave loss Coplannar Waveguide and precise V groove on Silicon Substrate for Optoelectronic Packaging - art. no. 601938

Optoelectronic packaging has become a most important factor that influences the final performance and cost of the module. In this paper, low microwave loss coplanar waveguide(CPW) on high resistivity silicon(HRS) and precise V groove in silicon substrate were successfully fabricated. The microwave attenuation of the CPW made on HRS with the simple process is lower than 2 dB/cm in the frequency range of 0 similar to 26GHz, and V groove has the accuracy in micro level and smooth surface. These two techniques built a good foundation for high frequency packaging and passive coupling of the optoelectronic devices. Based on these two techniques, a simple high resistivity silicon substrate that integrated V groove and CPW for flip-chip packaging of lasers was completed. It set a good example for more complicate optoelectronic packaging.

原子核质量的高精度测量；Precise mass measurement of nuclides

原子核的质量直接反映了核内强相互作用、电磁相互作用和弱相互作用的结果.文章简要阐述了原子核质量测量的意义、现状和主要方法,介绍了基于兰州重离子冷却储存环的原子核质量测量实验,比较了首次得到的63Ge,65As,67Se和71Kr核质量测量值与理论计算结果,探讨了65As质量对天体物理快质子俘获过程的影响,文章最后给出了今后的研究内容.中国科学院近代物理研究所在轻质量丰中子区,系统测量了从Ne到Ca核素的质量,研究了N=20和28幻数随中子数和质子数变化的演化;在丰质子区,精确测量了快质子俘获路径上关键核素的质量,为解释X射线暴等爆发性天体过程提供重要的质量数据;在中重丰中子区,系统地测量丰中子核质量,通过天体网络计算模拟超新星爆发中的快中子俘获过程.

ON THE SIGNIFICANCE OF WAVELENGTH POSITIONING ACCURACY IN MULTICOMPONENT ANALYSIS TECHNIQUES FOR THE CORRECTION OF LINE INTERFERENCES IN INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

The present paper reports some definite evidence for the significance of wavelength positioning accuracy in multicomponent analysis techniques for the correction of line interferences in inductively coupled plasma atomic emission spectrometry (ICP-AES). Using scanning spectrometers commercially available today, a large relative error, DELTA(A) may occur in the estimated analyte concentration, owing to wavelength positioning errors, unless a procedure for data processing can eliminate the problem of optical instability. The emphasis is on the effect of the positioning error (deltalambda) in a model scan, which is evaluated theoretically and determined experimentally. A quantitative relation between DELTA(A) and deltalambda, the peak distance, and the effective widths of the analysis and interfering lines is established under the assumption of Gaussian line profiles. The agreement between calculated and experimental DELTA(A) is also illustrated. The DELTA(A) originating from deltalambda is independent of the net analyte/interferent signal ratio; this contrasts with the situation for the positioning error (dlambda) in a sample scan, where DELTA(A) decreases with an increase in the ratio. Compared with dlambda, the effect of deltalambda is generally less significant.

WAVELENGTH POSITIONING ERRORS AND TRUE DETECTION LIMIT IN RELATION TO MULTICOMPONENT ANALYSIS TECHNIQUES FOR THE CORRECTION OF LINE INTERFERENCES IN INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

The present paper deals with the evaluation of the relative error (DELTA(A)) in estimated analyte concentrations originating from the wavelength positioning error in a sample scan when multicomponent analysis (MCA) techniques are used for correcting line interferences in inductively coupled plasma atomic emission spectrometry. In the theoretical part, a quantitative relation of DELTA(A) with the extent of line overlap, bandwidth and the magnitude of the positioning error is developed under the assumption of Gaussian line profiles. The measurements of eleven samples covering various typical line interferences showed that the calculated DELTA(A) generally agrees well with the experimental one. An expression of the true detection limit associated with MCA techniques was thus formulated. With MCA techniques, the determination of the analyte and interferent concentrations depend on each other while with conventional correction techniques, such as the three-point method, the estimate of interfering signals is independent of the analyte signals. Therefore. a given positioning error results in a larger DELTA(A) and hence a higher true detection limit in the case of MCA techniques than that in the case of conventional correction methods. although the latter could be a reasonable approximation of the former when the peak distance expressed in the effective width of the interfering line is larger than 0.4. In the light of the effect of wavelength positioning errors, MCA techniques have no advantages over conventional correction methods unless the former can bring an essential reduction ot the positioning error.

精密复杂曲面重构与多轴数控加工刀位规划策略

数控加工作为现代制造中的标志性加工技术，在航空航天、运载工具、动力装备等领域的精密复杂型面加工中占据着主导地位。随着国内高速数控加工中心及高档数控机床等硬件设备的日趋成熟和普及，围绕高速数控加工的一些深层次问题便逐步显现出来，这突出表现在数控机床的高速加工特性与传统加工方法之间的矛盾。本文将主要围绕复杂型面高速数控加工中的两大关键技术：曲面造型技术与刀位规划策略，展开论述，着重解决其中的一些关键科学问题，以期为复杂型面的高速数控加工提供新的技术支持。 1. 以罐车曲面重构为例，详细论述了从不完整散乱数据到曲面精确重构的整个过程，着重解决了自由曲面重构理论在实际应用中遇到的一些问题。针对不完整散乱数据，提出一种散乱数据的有序化处理方法，同时给出了面向NURBS的数据自动参数化策略，用于构造罐车的系列截面轮廓线。然后以曲面蒙皮操作为基础实现罐车曲面的快速重构。最后利用参数曲面的离散表达，完成罐车容积的快速检定并借以验证罐车曲面重建的精确性。 2. 以Bézier曲线/曲面为基础，运用多元Bernstein多项式算术运算，将点到复杂曲线/曲面最近点的计算转化为Bernstein多项式方程的求解，进而基于Bernstein基函数的线性精度性质，给出一种新的最近点计算模型。然后通过de Casteljau快速分割算法和二叉/四叉树递归分解的搜索策略寻找最近点。该方法可以有效避免繁琐的迭代计算和对初始值的选择，并从计算效率入手，对其加以改进，成功实现了分割算法与Newton-Raphson方法的融合。再利用B样条曲线/曲面与Bézier曲线/曲面之间成熟的转换算法，将所提出的方法进一步推广到应用更为广泛的B样条曲线/曲面。 3. 通过对刀具轨迹有效性的分析，将刀具轨迹规划分为曲面上曲线族的选择和有效合理排布方式的设计两个方面，为刀具轨迹规划提供了新的设计思路。并以此为基础，对最优刀具轨迹的定义进行了重新阐述，指出今后刀具轨迹规划的研究必须综合考虑轨迹的几何、刀具的运动以及机床的动力学特性。 4. 针对数控加工中心高速加工特性，提出一种等参数螺旋轨迹生成方法。该方法以减少抬刀和路径转接为目的，并综合考虑刀具轨迹几何与运动力学性能，特别适合自由曲面的高速数控加工。同时，在刀具路径的链接、误差分析等方面，也提出了一些颇具特色的方法，从而避免了传统偏置轨迹繁琐的自交干涉检测，能够有效抑制刀具负载的波动，减小刀具的磨损。 5. 在正确重建网格模型拓扑关系的基础上，从离散微分几何学这一新的角度入手，给出了一种新的三角网格曲面微分几何特性分析方法，进而以参数曲面上曲线偏置方法为基础，结合三角网格曲面的拓扑结构和局部区域的精确拟合，建立了网格曲面上的曲线偏置模型，并将计算最近点的方法进一步推广用来计算曲面上的偏置点，从而避免了繁琐的迭代计算。以此为基础，对网格模型的边界轮廓进行等残留偏置，给出了网格曲面上的等残留刀具轨迹生成方法。可进一步利用螺旋线连接各条轨迹，生成更为光滑刀具路径。

一种TEC地图构建方法与全球电子总含量的气候学研究

Global positioning system (GPS) can not only provide precise service for navigation and timing, but also be used to investigate the ionospheric variation. From the GPS observations, we can obtain total electron content (TEC), so-called GPS TEC, which is used to characterize the ionospheric structure. This thesis mainly concerns about GPS TEC data processing and ionospheric climatological analysis as follows. Firstly, develop an algorithm for high-resolution global ionospheric TEC mapping. According to current algorithms in global TEC mapping, we propose a practical way to calibrate the original GPS TEC with the existing GIM results. We also finish global/local TEC mapping by model fitting with the processed GPS TEC data; in practice, we apply it into the local TEC mapping in Southeast of China and obtain some initial results. Next, suggest a new method to calculate equivalent ionospheric global electron content (GEC). We calculate such an equivalent GEC with the TEC data along the geographic longitude 120°E. With the climatological analysis, we can see that GEC climatological variation is mainly composed of three factors: solar cycle, annual and semiannual variations. Solar cycle variation is dominant among them, which indicates the most prominent influence; both annual and semiannual variations play a secondary role and are modulated by solar activity. We construct an empirical GEC model driven by solar activity and seasonal factors on the basis of partial correlation analysis. Generally speaking, our researches not only show that GPS is advantageous in now-casting ionospheric TEC as an important observation, but also show that GEC may become a new index to describe the solar influence on the global ionosphere since the great correlation between GEC and solar activity factor indicates the close relationship between the ionosphere and solar activity.