80K分置式斯特林制冷机连接软管动力特性的模拟与验证

建立了 80 K分置式斯特林制冷机连接软管的理论模型 ,通过对控制方程进行处理及合理简化 ,对边界条件的处理引入特征线法 ,通过数值计算对控制方程进行了求解 ,通过实验对理论模拟结果进行了验证 ,证明了本模拟方法具有良好的准确性。     

Solutions for ion-electron-radiation coupling with radiation and electron diffusion

We present semi-analytic solutions to the equations for radiation-electron-ion coupling, the so-called 3-T equations. Our solutions use a linearization based on Pomraning's form for the heat capacity given by with additional stipulations for the electron heat conduction and ion-electron coupling coefficients. To solve the linearized equations we use integral transform techniques and compute a Fourier integral numerically. We give solutions for a 3-T version and a 2-T with heat conduction version of the Su-Olson problem as well as solutions for spherical and spherical shell sources. We use the xRage radiation hydrodynamics code to demonstrate that our solutions are useful for code verification in multiple dimensions and axisymmetric geometries.     

检定声级计有关性能用猝发声的研究

在相关标准中,规定检定声级计有关性能用的猝发声必须“零起零落”。本文通过实验验证指出,猝发声“零起零落”与否,对声级计的检定结果有明显影响,但其差别远小于相应容差的1／10,这一差别对计量检定要求来说是很小的,可忽略不计。因而,在声级计检定中没有必要强调猝发声必须“零起零落”。     

Calibration uncertainty

Methods recommended by the International Standardization Organisation and Eurachem are not satisfactory for the correct estimation of calibration uncertainty. A novel approach is introduced and tested on actual calibration data for the determination of Pb by ICP-AES. The improved calibration uncertainty was verified from independent measurements of the same sample by demonstrating statistical control of analytical results and the absence of bias. The proposed method takes into account uncertainties of the measurement, as well as of the amount of calibrant. It is applicable to all types of calibration data, including cases where linearity can be assumed only over a limited range. Received: 25 August 2001 Accepted: 21 December 2001     

Differentially Private Significance Tests for Regression Coefficients

Many data producers seek to provide users access to confidential data without unduly compromising data subjects’ privacy and confidentiality. One general strategy is to require users to do analyses without seeing the confidential data; for example, analysts only get access to synthetic data or query systems that provide disclosure-protected outputs of statistical models. With synthetic data or redacted outputs, the analyst never really knows how much to trust the resulting findings. In particular, if the user did the same analysis on the confidential data, would regression coefficients of interest be statistically significant or not? We present algorithms for assessing this question that satisfy differential privacy. We describe conditions under which the algorithms should give accurate answers about statistical significance. We illustrate the properties of the proposed methods using artificial and genuine data. Supplementary materials for this article are available online.     

A verified inexact implicit Runge–Kutta method for nonsmooth ODEs

Structural pounding and oscillations have been extensively investigated by using ordinary differential equations (ODEs). In many applications, force functions are defined by piecewise continuously differentiable functions and the ODEs are nonsmooth. Implicit Runge–Kutta (IRK) methods for solving the nonsmooth ODEs are numerically stable, but involve systems of nonsmooth equations that cannot be solved exactly in practice. In this paper, we propose a verified inexact IRK method for nonsmooth ODEs which gives a global error bound for the inexact solution. We use the slanting Newton method to solve the systems of nonsmooth equations, and interval method to compute the set of matrices of slopes for the enclosure of solution of the systems. Numerical experiments show that the algorithm is efficient for verification of solution of systems of nonsmooth equations in the inexact IRK method. We report numerical results of nonsmooth ODEs arising from simulation of the collapse of the Tacoma Narrows suspension bridge, steel to steel impact experiment, and pounding between two adjacent structures in 27 ground motion records for 12 different earthquakes. This work is partly supported by a Grant-in-Aid from Japan Society for the Promotion of Science and a scholarship from Egyptian Government.     

基于活性顺序图的形式化验证方法及工具研究

近年来,形式化验证方法在软件开发过程的作用越来越大。如何充分利用形式化验证方法提高软件系统的可靠性已成为软件开发者及使用者主要关注的问题。总结了近年来基于活性顺序图的形式化验证方法的研究进展,首先介绍活性顺序图的语言及其表达能力与复杂性,然后深入分析现有的基于活性顺序图的形式化验证的关键技术及其典型应用,最后实现一种基于活性顺序图的运行时验证工具,实验证明使用本验证工具进行形式化验证的可行性。     

Comparative regression analysis coupled with rational verification for forecasting night cooling

A set of linear regression equations has been developed for forecasting night-time minimum temperatures. The predictors used in each regression are the dry-bulb and wet-bulb temperatures recorded at various times during the day. This set of regression equations can be used to begin estimating the expected minimum temperature early in the day and then update the estimate in the course of the day. It is shown that these regression equations are quite insensitive to small deviations in the input data and some special cases are discussed. The usefulness of simple or multiple regression is also examined. Under certain conditions, linear regression on hygrometrically derived humidity parameters have been transformed into non-linear expressions of dry and wet-bulb temperatures. It is shown by an example that these non-linear relationships may fit the data equally as well as the linear relationships. Comparative verification of the scheme has shown that successive updating of the predicted minimum temperature has certain advantages. Questions associated with the representativeness of the data base are also discussed. The effect of the turbulent mixing by the wind on the night cooling is incorporated in the scheme as a further upgrading of the method.     

The development and inter-laboratory verification of LC-MS libraries for organic chemicals of environmental concern

The development, verification, and comparison study between LC-MS libraries for two manufacturers’ instruments and a verified protocol are discussed. Compounds in the libraries are among those considered by the U.S. EPA Office of Water as threats to drinking water including pesticides, drugs of abuse, and pharmaceuticals. The LC-MS library protocol was verified through an inter-laboratory study that involved Federal, State, and private laboratories. The results demonstrated that the libraries are transferable between the same manufacturer's product line, and have applicability between manufacturers. Although ion abundance ratios within mass spectra were shown to be different between the manufacturers’ instruments, the NIST search engine match probability was at 96% or greater for 64 out of 67 compounds evaluated.     

Experiences using IAEA Code of practice for radiation sterilization of tissue allografts: Validation and routine control

Problems of tissue allografts in using International Standard (ISO) 11137 for validation of radiation sterilization dose (RSD) are limited and low numbers of uniform samples per production batch, those are products obtained from one donor. Allograft is a graft transplanted between two different individuals of the same species. The minimum number of uniform samples needed for verification dose (VD) experiment at the selected sterility assurance level (SAL) per production batch according to the IAEA Code is 20, i.e., 10 for bio-burden determination and the remaining 10 for sterilization test. Three methods of the IAEA Code have been used for validation of RSD, i.e., method A1 that is a modification of method 1 of ISO 11137:1995, method B (ISO 13409:1996), and method C (AAMI TIR 27:2001). This paper describes VD experiments using uniform products obtained from one cadaver donor, i.e., cancellous bones, demineralized bone powders and amnion grafts from one life donor. Results of the verification dose experiments show that RSD is 15.4 kGy for cancellous and demineralized bone grafts and 19.2 kGy for amnion grafts according to method A1 and 25 kGy according to methods B and C.