Ramifications of Risk Measures in Implementing Quantitative Performance Assessment for the Proposed Radioactive Waste Repository at Yucca Mountain, Nevada, USA

As part of its preparation to review a potential license application from the U.S. Department of Energy (DOE), the U.S. Nuclear Regulatory Commission (NRC) is examining the performance of the proposed Yucca Mountain nuclear waste repository. In this regard, we evaluated postclosure repository performance using Monte Carlo analyses with an NRC-developed system model that has 950 input parameters, of which 330 are sampled to represent system uncertainties. The quantitative compliance criterion for dose was established by NRC to protect inhabitants who might be exposed to any releases from the repository. The NRC criterion limits the peak-of-the-mean dose, which in our analysis is estimated by averaging the potential exposure at any instant in time for all Monte Carlo realizations, and then determining the maximum value of the mean curve within 10000 years, the compliance period. This procedure contrasts in important ways with a more common measure of risk based on the mean of the ensemble of peaks from each Monte Carlo realization. The NRC chose the former (peak-of-the-mean) because it more correctly represents the risk to an exposed individual. Procedures for calculating risk in the expected case of slow repository degradation differ from those for low-probability cases of disruption by external forces such as volcanism. We also explored the possibility of risk dilution (i.e., lower calculated risk) that could result from arbitrarily defining wide probability distributions for certain parameters. Finally, our sensitivity analyses to identify influential parameters used two approaches: (1). the ensemble of doses from each Monte Carlo realization at the time of the peak risk (i.e., peak-of-the-mean) and (2). the ensemble of peak doses calculated from each realization within 10000 years. The latter measure appears to have more discriminatory power than the former for many parameters (based on the greater magnitude of the sensitivity coefficient), but can yield different rankings, especially for parameters that influence the timing of releases.     

Simultaneous prediction intervals for multiple comparisons with a standard

k normal populations having common variance are used to construct two-sided and one-sided simultaneous prediction intervals for the differences between the future means of independent random sample from each of these populations compared to a standard. These prediction intervals are particularly useful if one has sampled the performance of several products and wishes to simultaneously predict the differences between future sample mean performance of these products and a standard with a predetermined joint probability. Methods on sample size determination are also given. The procedures are illustrated with a numerical example. Received: February 25, 2000; revised version: February 6, 2001     

关于长江中游城市圈、城镇体系与城市化水平的研究

以长江中游华中经济圈范围内的城市圈与城镇体系为研究对象，从城市、城市圈与城镇体系的现状、各城市圈及城镇体系目前具备的优势与不足，城市化水平分析的方法及指标体系等方面分别进行了研究，提出了城市圈、城镇体系与城市化水平的发展规划，指出了推动大城市经济圈的发展是长江中游华中经济圈发展的重要途径，也是华中经济圈在21世纪迅速腾飞的必然选择。华中经济圈的城市化水平的进一步提高，可推动长江中游华中经济圈内工业化和经济的可持续发展。     

东西部地区企业职工培训投资与收益的实证分析

通过对东西部地区制造业企业在职培训投资与收益的实证研究,发现,东西部地区企业在职培训与工资收入密切相关。东西部地区培训投资的差距可以部分地解释工资收入差距。西部企业较低的生产技术水平,不利于企业长期的培训投资和工资收入的增加。     

模块教学法在物理学教学中的应用

物理学是一门自然科学的基础课,物理学与很多的专业课存在着密切联系.根据各专业的特点,要求学生学习物理时侧重面应有所不同.分析了传统教学模式的缺陷,并在此基础上,提出了一种比较适合当前形势的一种教学方法,即模块教学法.     

一类非线性二阶微分系统两点边值问题

给出了一类非线性二阶微分系统两点边值共振问题可解的一组充分条件.     

激光双光子激发测量Xe原子3P系列能级寿命

本文论述了激光双光子感应荧光法对原子能级寿命的测量。利用激光窄带有选择地激发Xe原子的3P系列能级，从而测量了它们的能缓寿命，观测到的荧光衰变曲线显示出很好的单指数衰变曲线，因而消除了电子宽带激发所带来的级联效应，使能级寿命测量更加精确。     

城市化水平综合测度模型研究

目前 ,关于城市化水平的研究只把人口城市化作为唯一的测度指标 ,这种做法不免有些片面。本文提出了全面评价城市化水平的综合测度模型 ,并对中国的城市化水平进行了测度。     

双轴自动电子倾斜测试仪

双轴自动电子倾斜测试仪是一个高精度、大量程的角度倾斜测量仪器。本文介绍了该仪器的原理和性能,给出了技术指标和实测结果,最后阐明了它的应用领域。     

强势场中非线性谐振子的能级

将微扰论与变分法相结合,求出了强势场中非线性谐振子的基态能级和部分激发态能级,其中基态能级的精确度约为2%.