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一种高精度、大量程时间间隔计数器的设计 总被引:1,自引:0,他引:1
车震平 《核电子学与探测技术》2011,31(6)
时间间隔测量方法有多种,如计数法、游标法、模拟内插法、延迟线内插法、时间电压变换法等.通过对这几种测量方法的分析比较,提出了一种大量程、高精度的时间间隔测量方法,并从实现原理和设计方法进行了阐述.该方法已成功应用于GPS铷钟中,对于同类时间间隔计数器设计具有借鉴意义. 相似文献
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温度噪声相关测速方法的系统误差与自标定 总被引:2,自引:1,他引:1
研究了流体噪声的湍流传递行为及信号源的性质对相关测速系统的影响,分析了相关测速系统的系统误差,并提出了理论修正该误差的方法,使得相关测速成为一种绝对的测量方法。在理论分析的基础上进行了实验研究,理论与实践得到了较好的统一。 相似文献
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中子多重性测量技术作为一种全新的NDA分析方法,主要用于核保障领域的核材料衡算测量,是传统符合中子测量方法的改进。使用该技术可实现复杂情况下样品的准确测量。 相似文献
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本文介绍了我国常用的环境空气中氡的测量方法和仪器。文中还针对每一种测量方法的适用范围和注意事项等作了评价,最后简要叙述了氡浓度测量的质量保证措施。 相似文献
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一、测量方法 采用国产WGJ-1型激光铀分析仪进行测量。测量方法有两种,即标准曲线法和标准加入法。标准曲线法是预先用不同浓度的标准液做出标准曲线,在测量样品后直接从曲线上查出相应的铀含量;这一方法在测量时对温度要求较高。标准加入法是在每次测量对加入一定量的标准溶液,并与不加标准铀液时的计数相比以求出铀含量。本文的测量采用标准 相似文献
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流致振动电磁测量装置的研究 总被引:1,自引:0,他引:1
高天万 《核电子学与探测技术》2001,21(3):232-233,236
流致振动其本质是一个固液耦合问题,数学处理十分复杂,这里介绍一种电磁测量方法。由于测量中,探测器和流体管道不存在相对运动和影响流场的问题,提高了测量的精度和可信度。 相似文献
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Tomoaki Watanabe Tomohiro Endo Akio Yamamoto Yasuhiro Kodama Yasunori Ohoka Tadashi Ushio 《Journal of Nuclear Science and Technology》2013,50(5):590-599
A cross section adjustment method based on the random sampling technique is proposed. In the proposed method, correlations among cross sections and core parameters are used instead of sensitivity coefficients of cross sections, which are necessary in the conventional method. The correlations are statistically estimated by the random sampling technique. The proposed method is theoretically consistent with the conventional method and provides comparable adjusted cross sections when sufficient number of random sampling is taken into account. The proposed method would be suitable for practical light water reactor (LWR) core analysis since estimation of sensitivity coefficients, which requires considerable computational cost in typical LWR problems, is not necessary. Through a benchmark problem in simple pin-cell geometry, adjusted cross sections by the present and the conventional cross section adjustment method are compared. The adjusted cross sections by the present method well reproduce the conventional ones, thus the feasibility of the present method is confirmed. 相似文献
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Kenji Yokoyama Makoto Ishikawa Teruhiko Kugo 《Journal of Nuclear Science and Technology》2013,50(12):1165-1174
An extended cross-section adjustment method has been developed to improve the prediction accuracy of target core parameters. The present method is on the basis of a cross-section adjustment method which minimizes the uncertainties of target core parameters under the conditions that integral experimental data are given. The present method enables us to enhance the prediction accuracy better than the conventional cross-section adjustment method by taking into account the target core parameters, as well as the extended bias factor method. In addition, it is proved that the present method is equivalent to the extended bias factor method when only one target core parameter is taken into account. The present method is implemented in an existing cross-section adjustment solver. Numerical calculations verify the derived formulation and demonstrate an applicability of an adjusted cross-section set which is specialized for the target core parameters. 相似文献
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Yuichiro Ban Tomohiro Endo Akio Yamamoto 《Journal of Nuclear Science and Technology》2013,50(5):496-515
A unified numerical method based on the factorization approach is developed to solve the space-dependent neutron kinetic equation. Various numerical methods for solving the space-dependent kinetic equation have been developed so far. These methods can be classified into two categories, i.e., the direct and the factorization methods. The factorization method is known as an effective numerical method. In the present study, a new factorization method named the multigrid amplitude function (MAF) method is developed. Unlike the improved quasi-static (IQS) method, an independent amplitude function is assigned for each spatial region and energy group in the MAF method. The MAF method is a generalization of conventional methods, e.g., the frequency transform, IQS, and Theta methods. To evaluate the amplitude function in the MAF method, the time-dependent coarse-mesh finite difference (TCMFD) method is developed. The MAF method is implemented into a space-dependent kinetic code on the basis of the analytical polynomial nodal method. In order to verify the effectiveness of the MAF method, the TWIGL, Langenbuch, Maurer, and Werner (LMW), and Laboratorium für Reaktorregelung and Anlagensicherung (LRA) benchmark problems are analyzed. The calculation results show the effectiveness of the present method. 相似文献
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移动粒子半隐式(MPS)方法是一种完全基于拉格朗日体系的粒子法,应用于不可压缩流体。MPS方法在描述存在大变形和相变的问题时具有很大的优势。然而当MPS方法中的Laplace模型应用于求解能量方程时会存在求解不精确的情况。本文在MPS方法的基础上,提出了一种粒子 网格混合求解方法。通过MPS方法求解动量守恒方程,耦合有限体积法(FVM)求解能量守恒方程,以达到对对流传热问题的精确求解。对一维导热问题进行了方法验证,证明了粒子 网格混合方法求解导热的有效性,并有较高的求解精度。利用粒子-网格混合方法模拟了方腔内的自然对流,结果表明,基于MPS方法和FVM的耦合方法可用于求解对流传热问题。 相似文献
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α放射性比的测定方法 总被引:3,自引:3,他引:0
采用了3种α放射性比的测定方法:几何级数法、外推法和曲线拟合法。检验了几何级数法的可靠性。把外推法、曲线拟合法的结果与几何级数法的结果作了比较。 相似文献
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The superposition technique is a simple yet powerful method for soil-structure seismic interaction problems. The method essentially consists of obtaining total motions by superposing free field motions and interaction motions, both previously calculated in separate analyses. Although this method is strictly applicable only to linear systems, the equivalent linear method is easily incorporated in order to approximate soil non-linearities. The superposition technique is valid for 3-D geometries, and allows for a seismic environment consisting of any kind of body or surface waves, or combinations thereof. The method is explained in detail, and three case studies are also summarized as an illustration of the flexibility of the method. 相似文献
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在γ能谱数据处理中需要对测量能谱进行光滑以降低统计涨落。实际应用中,针对不同的γ能谱,需要对各种能谱光滑算法的光滑效果进行科学的比较和评价,选择最佳的能谱光滑算法及最佳光滑参数。文章从γ能谱计数的统计涨落规律出发,提出了一种评价能谱光滑算法效果的方法,给出了评价参数,并计算了光滑效果的等效测量时间。根据实验测量的γ能谱数据,采用5点三次多项式拟合最小二乘法对不同光滑次数的光滑效果进行了对比,优选了光滑算法的光滑次数参数,并给出了等效测量时间,提高了谱数据处理的精度和准确度。 相似文献
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Two methods of seismic analysis of non-classically damped systems are compared. The first method is an extension of the Foss method (called the modified Foss method here) in which the response in the time domain is represented in terms of real modal vectors and relative displacements and velocities of the equivalent single-degree-of-freedom (SDOF) systems. In the second method, known as the canonical method, a different set of real modal vectors along with sine and cosine responses of the equivalent SDOF systems are used. It is shown that the canonical method can be derived along the same lines as the modified Foss method. The time domain responses from the two methods are identical and the corresponding response spectra responses comparable. The modified Foss method is preferred because of the physical significance of the relative displacements and velocities used in the method. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(2):243-255
The spatial discretization form of the space-dependent reactor kinetics equation is a first-order simultaneous ordinary differential equation in time. Conventional numerical methods of the space-dependent kinetics equation, i.e., the generalized Runge-Kutta method, the implicit method (backward Euler method), and the Theta method, are based on the time difference approximation. However, the present study adopts the analytical solution of the space-dependent kinetics equation expressed by the matrix exponential and no time difference approximation is used. In this context, our present approach is classified as an explicit method in which no iteration calculation on space and energy is necessary. The Krylov subspace method is used to evaluate the matrix exponential observed in the solution of the spatially discretized space-dependent kinetics equation. The Krylov subspace method is implemented into a space-dependent kinetics solver. In order to examine the effectiveness of the Krylov subspace method, the TWIGL benchmark problem is analyzed as a verification calculation. The calculation results show the effectiveness of the present method especially in the step reactivity perturbation. 相似文献
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材料电磁脉冲屏蔽效能的时域测量方法 总被引:1,自引:0,他引:1
材料电磁屏蔽效能的窗口法测量本质上是一种孔缝耦合效应的测量,具有低频响应不好,测量误差大等不足.且窗口法难以实现材料对电磁脉冲的屏蔽效能的测量.针对窗口法的不足,提出了试件法测量材料电磁脉冲屏蔽效能的试验方法.给出了试件法的原理、试件外环境场的获取方法及试件内测点的布局等关键技术.与窗口法相比,试件法具有试验简单、不需要微波暗室、试验效率高,试验数据可靠等一系列优点.利用试件法对某特种水泥材料的电磁脉冲屏蔽效能进行了测量,测量结果与理论分析符合得较好,证明了该试验方法的有效性. 相似文献