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流动注射氢化物发生-蒸气贮存脉冲进样原子荧光法测定地质样品中的痕量砷 总被引:1,自引:0,他引:1
本文研究了流动注射氢化物发生-蒸气贮存脉冲进样原子荧光法测定地质样品中痕量砷的方法,砷的灵敏度提高17.6倍,精密度(RSD)为2.1%,检出限为0.32ng/mL。用于地质标准样的测定,结果满意。 相似文献
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A. C. Rao 《Journal of Optimization Theory and Applications》1979,29(1):147-153
The closure equation of a four-bar linkage generally gives a nonzero result, which may be taken as an index of the error in the output for a given input. The actual output can be brought close to the desired value by specifying the mean error permissible in the entire range of operation and by minimizing the variance (standard deviation). The present method differs from the closed-form synthesis (i.e., precision-point synthesis), in the sense that it does not limit the number of precision points. The results show that the present method compares well with other methods. 相似文献
125.
Head space GC using a special electropneumatic sampling system works well in combination with glass capillaries. Because a homogenous gas mixture is already present most problems inherent with inlet splitters are thus avoided. In cases where the high vapor pressure of the sample can cause problems with the pressure controlled sampling system, the use of narrow bore glass capillaries provides the necessary inlet pressure. The use of this powerful and convenient analytical tool for water pollution analysis, flavour analysis and the analysis of volatiles in crude oil samples is shown by examples. 相似文献
126.
光电精确制导战术武器的发展 总被引:4,自引:0,他引:4
本文简述光电精确制导技术武器发展的基本特征,探讨新一代自动寻的精确制导战术武器发展的趋势和技术途径,分析精确制导战术武器的关键技术。 相似文献
127.
空地激光通信跟踪精度主要外界影响因素研究 总被引:7,自引:5,他引:2
为了分析空地激光通信外界因素对跟踪精度的影响情况,将平台振动、大气湍流和背景光三个主要影响因素归结到对跟踪精度影响的统一框架下进行了研究。使用实际测量得到的平台振动数据,建立空地激光通信跟踪仿真系统,分析了不同条件下,三种外界因素对跟踪精度的综合影响情况。在文中假设基础上,分析可知:粗跟踪单元可以较好的抑制地面运动平台的振动,保证激光能够进入精跟踪视场;中强度的湍流使精跟踪残差标准差增大4倍左右,如果试验地点选择在高海拔地区,大气湍流使精跟踪残差标准差增大2倍左右。 相似文献
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129.
Vignon Oussa 《Journal of Functional Analysis》2018,274(4):1202-1254
In this work, we provide a unified method for the construction of reproducing systems arising from unitary irreducible representations of some solvable Lie groups. In contrast to other well-known techniques such as the coorbit theory, the generalized coorbit theory and other discretization schemes, we make no assumption on the integrability or square-integrability of the representations of interest. Moreover, our scheme produces explicit constructions of frames with precise frame bounds. As an illustration of the scope of our results, we highlight that a large class of representations which naturally occur in wavelet theory and time–frequency analysis is handled by our scheme. For example, the affine group, the generalized Heisenberg groups, the shearlet groups, solvable extensions of vector groups and various solvable extensions of non-commutative nilpotent Lie groups are a few examples of groups whose irreducible representations are handled by our method. The class of representations studied in this work is described as follows. Let G be a simply connected, connected, completely solvable Lie group with Lie algebra . Next, let π be an infinite-dimensional unitary irreducible representation of G obtained by inducing a character from a closed normal subgroup of G. Additionally, we assume that , is a closed subgroup of G, is a fixed Haar measure on the solvable Lie group M and there exists a linear functional such that the representation is realized as acting in . Making no assumption on the integrability of , we describe explicitly a discrete subset Γ of G and a vector such that is a tight frame for . We also construct compactly supported smooth functions s and discrete subsets such that is a frame for . 相似文献
130.
《Applied and Computational Harmonic Analysis》2020,48(3):868-890
In this paper, we study regression problems over a separable Hilbert space with the square loss, covering non-parametric regression over a reproducing kernel Hilbert space. We investigate a class of spectral/regularized algorithms, including ridge regression, principal component regression, and gradient methods. We prove optimal, high-probability convergence results in terms of variants of norms for the studied algorithms, considering a capacity assumption on the hypothesis space and a general source condition on the target function. Consequently, we obtain almost sure convergence results with optimal rates. Our results improve and generalize previous results, filling a theoretical gap for the non-attainable cases. 相似文献