三棱镜折射率测量结果的不确定度评定

根据不确定度的有关概念及具体实验教学模型 ,提出了测量不确定度的简化模式. 结合分光计 测三棱镜折射率的例子 ,进行了具体分析 ,给出了其测量不确定度的最终评定.     

分数填补下两非参数总体一般差异的经验似然置信区间

在一定的条件下证明了缺失数据情形基于分数填补方法得到的两非参数总体一般差异指标的经验似然比统计量的渐近分布为加权χ21,由此可构造差异指标的经验似然置信区间.     

磁粉法检测表面裂纹概率曲线的测定

本文介绍了利用实物零件测定裂纹检出概率的方法，并作出了用磁粉法检测表面裂纹的检测概率曲线，为大型构件检测周期的确定提供了可靠数据，为结构损伤容限设计，可靠性设计提供了重要的依据。     

Panel模型中的精确检验和置信区间

利用广义p-值和广义置信区间的概念,研究了Panel模型中未知参数的检验和置信区间问题.对于回归系数,分别考虑了单个情形和多个线性无关情形下的检验和置信区间问题,得到了精确检验和置信区间.对于方差分量,研究了其任意线性组合的检验和置信区间问题,建立了精确检验和置信区间.基于广义p-值和广义置信区间,获取精确检验和置信区间的方法具有计算方便、易应用于小样本问题的特点.最后,分别从理论和数值上研究了这些精确检验和置信区间的统计性质.     

Sample cleanup-free determination of mycophenolic acid and its glucuronide in serum and plasma using the novel technology of ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry

Mycophenolic acid (MPA) is an immunosuppressant drug which powerfully inhibits lymphocyte proliferation. Since the early 1990s it has been used to prevent rejection in organ transplantation. The requirement of therapeutic drug monitoring shown in previous studies raises the necessity of acquiring accurate and sensitive methods to measure MPA and its major metabolite mycophenolic acid glucuronide (MPAG).The authors developed a sample cleanup-free, rapid, and highly specific method for simultaneous measurement of MPA and MPAG in human plasma and serum using the novel technology of ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry. MPA- and MPAG-determinations were performed during a 2.0-min run time. Multiple calibration curves for the analysis of MPA and MPAG exhibited consistent linearity and reproducibility in the range of 0.05-100 (r > 0.999) mg L⁻¹ and 4-4000 mg L⁻¹ (r > 0.999), respectively. Limits of Detection were 0.014 mg L⁻¹ for MPA and 1.85 mg L⁻¹ for MPAG. Lower Limits of Quantification were 0.05 mg L⁻¹ for MPA and 2.30 mg L⁻¹ for MPAG. Interassay imprecision was <10% for both substances. Mean recovery was 103.6% (range 78.1-129.7%) for MPA and 111.1% (range 73.0-139.6%) for MPAG. Agreement was good for MPA and MPAG between the presented method and a validated HPLC-MS/MS method. The Passing-Bablok regression line for MPA and MPAG was HPLC-MS/MS = 1.14 UPLC-MS/MS—0.14 [mg L⁻¹], r = 0.96, and HPLC-MS/MS = 0.77 UPLC-MS/MS + 0.50 [mg L⁻¹], r = 0.97, respectively. This sample cleanup-free and robust LC-MS/MS assay facilitates the rapid, accurate and simultaneous determination of MPA and MPAG in human body fluids.     

液体中激光等离子体冲击波波前传播特性研究及测试

将空气中球对称冲击波衰减波前传播公式推广到非完全中心对称情况，根据对光学阴影法对激光等离子体冲击波波前测试数据的计算分析，提出液体中点源激光等离子体冲击波旋转椭球面波前传播公式.并且用声学方法对水中和酒精中的激光等离子体冲击波波前进行实验测试，结果表明测试结果与计算公式相吻合. 关键词： 激光 等离子体冲击波 旋转椭球面     

Light scattering by Gaussian random ellipsoid particles: First results with discrete-dipole approximation

We introduce the stochastic geometry of a Gaussian random ellipsoid (GE) and, with the discrete-dipole approximation, carry out preliminary computations for light scattering by wavelength-scale GE particles. In the GE geometry, we describe the base ellipsoid by the three semiaxes a?b?c. The axial ratios b:a and c:a appear as two shape parameters additional to those of the Gaussian random sphere geometry (GS). We compare the scattering characteristics of GE particles to those of ellipsoids. Introducing irregularities on ellipsoids smoothens the angular scattering characteristics, in a way analogous to the smoothening of spherical particle characteristics in the case of GS particles.     

Stability of principal components

In this article we deal with the problem of stability of the conclusions from principal components analysis over repeated samples. We define a measure of stability for each component and investigate some of the measures properties. We then obtain the maximum likelihood estimators (MLEs) of the measures, and derive their joint limiting distributions. The MLEs of the measures turn out to be asymptotically unbiased and jointly have the multivariate normal distribution. Modified estimators are also found to reduce the amount of bias in the MLEs. To facilitate interpretation of the measures we define stability confidence level as coverage probability, and associate with each measure a stability confidence level to describe the measure in terms of probability. Finally, we investigate the stability of the components via a simulation study and compare the performance of the MLEs and the modified estimators in terms of bias and precision. This work was sponsored by a grant from the Office of Vice-President for Research at Kuwait University under project number SS049.     

Modelling and forecasting mortality in Spain

Experience shows that static life tables overestimate death probabilities. As a consequence of this overestimation the premiums for annuities, pensions and life insurance are not what they actually should be, with negative effects for insurance companies or policy-holders. The reason for this overestimation is that static life tables, through being computed for a specific period of time, cannot take into account the decreasing mortality trend over time. Dynamic life tables overcome this problem by incorporating the influence of the calendar when graduating mortality. Recent papers on the topic look for the development of new methods to deal with this dynamism.     

非参数可修系统可用度的评定

考虑可修的串联系统,其单元产品在出现故障时,由于种种原因,故障不能得到及时维修,形成了一段保障延误时间.于是这一更新过程为:正常工作(直到出现故障)-保障延误-故障维修-正常工作…….假设每一时段的分布未知,且相互独立,给出了可用度的点估计和置信下限.