Criteria for Validity of the Maximum Norm Principle for Parabolic Systems

We consider systems of partial differential equations, which contain only second derivatives in the x variables and which are uniformly parabolic in the sense of Petrovskii. For such systems we obtain necessary and, separately, sufficient conditions for the maximum norm principle to hold in the layer Rn × ( 0,T ] and in the cylinder × ( 0,T], where is a bounded subdomain of Rn. In this paper the norm is understood in a generalized sense, i.e. as the Minkowski functional of a compact convex body in Rm containing the origin. The necessary and sufficient conditions coincide if the coefficients of the system do not depend on t. The criteria for validity of the maximum norm principle are formulated as a number of equivalent algebraic conditions describing the relation between the geometry of the unit sphere of the given norm and coefficients of the system under consideration. Simpler formulated criteria are given for certain classes of norms: for differentiable norms, p-norms ( 1 p ) in Rm, as well as for norms whose unit balls are m-pyramids, m-bipyramids, cylindrical bodies, m-parallelepipeds. The case m = 2 is studied separately.     

单轴晶体和各向同性介质交界面上e光光线的折射

根据光在各向异性介质中遵从的Ｆｅｒｍａｔ 原理,较系统地讨论了单轴晶体和各向同性介质交界面上的ｅ 光（ 非常光） 光线的折射,得到了光轴在任意取向情况下的折射基本公式。同时给出一般情况下确定ｅ 光线折射角的具体解。在此基础上对几种特殊的光轴取向给予了较详细的讨论。最后讨论了ｅ 光线的折射公式与ｅ 光波法线的折射定律的等价性,从而说明Ｆｅｒｍａｔ 原理与光的电磁波理论存在内在的一致性。     

关于最小不确定态的概率分布

本文借助于曲线坐标下动量算符的一种厄密形式,导出了广义坐标算符和广义动量算符的最小不确定态,并结合常见坐标分量取不同上、下限的情况讨论相应的概率分布,进而得到有关的结论.     

一种新型的两态叠加多模Schrdinger猫态光场的等阶N次方Y压缩

本文根据量子力学的线性叠加原理,构造了由多模（即q模时目平态的相反态|｛｛－Zj｝〉q及多模虚相干态|｛｛－Zj｝〉q这两者的线性叠加所组成的一种新型的多模Schrodinger猫态光场利用新近建立的多模压缩态理论,研究了态的N次方Y压缩效应,结果发现：①当压缩阶数N＝Zp且p＝2m（m＝1,2,3,…,…）时,态。总是恒处于N－Y最小测不准态;②当压缩阶数N＝2p且p＝2m＋1（m＝0,1,2,3,…,…）时,如果各模的初始相位,态间的初始相位差以及各单模相干态光场的平均光子数之总和等满足一定的量子化条件,则态可呈现出周期性变化的、任意阶的N次方Y压缩效应;③当压缩阶数N＝2P＇＋1时,无论p＇＝2m（m＝0,1,2,…,…）还是p＇＝2m＋1（m＝0,1,2,3,…,……）,只要各模的初始相位满足一定的量子条件,则当两态叠加几率幅满足时,态就恒处于N－Y测不准态,始终不呈现N－Y最小测不准态和N次方Y压缩;而当时,态始终不呈现N－Y测不准态、N－Y最小测不准态和N次方Y压缩效应．     

相关系数对伏安法测电阻不确定度的影响

本文在考虑电压和电流相关系数的影响下,给出了伏安法测电阻实验中待测电阻的不确定度表示。     

Radiation: Waves or particles? A quantized approach to time

A fundamental difficulty in theoretical physics is the dual and apparently incompatible interpretations of radiation as showing both continuous and extensive wave properties but also those of discrete atomic or smaller individual particles. Some of these contradictions are outlined. The explanation offered is of a quantized nature of time; units t_o=h/m_oc² for a particle at rest, and of similar interval unit s_o when in relative motion, with conventional relativistic corrections.

For many purposes this form of quantization replaces the need for a wave concept which then appears as a mathematical approach, chosen to avoid the physical concept of an intrinsicc time for any particle, just as we have for its intrinsic mass, spin and electrical charge. t_o and s_o are directly related to its frequency, energy and mass. The uncertainty principle and interference relations follow directly from this model, without any physical wave concept.     

可移动式微量氧分析仪检定装置研制

研制一种新型可移动式微量氧分析仪检定装置。该装置由标准气体、零点气、脱氧纯化器、减压阀、调节阀、4通阀、5通阀、不锈钢管路、流量控制系统、移动平台等组成。该装置气密性好,15 min内可将装置内氧气浓度由20.9%降至不大于0.1μmol/mol,对于0~10μmol/mol的微量氧分析仪检定结果的扩展不确定度为Urel=1.7%FS(k=2)。该装置满足气体标准物质的连续切换和在线检定的需要,检定时间短,结果准确可靠,可为在线式和非在线式微量氧分析仪的量值溯源提供有效保障。     

Uncertainty of the Thermal Conductivity Measurement Using the Transient Hot Wire Method

This work deals with uncertainty analysis of the thermal conductivity measurement using the transient hot wire method. The characterization is made from a sample of low-density, polyethylene BRALEN SA 200-22. The utilized experimental data are obtained from the test measurements performed on the air at room temperature. The sources of measurement errors are analyzed and the uncertainty of the measured value of the thermal conductivity is evaluated. The analysis shows that in the present case the uncertainty of the thermal conductivity measurement is about ±3.3% for 68% confidence level.This revised version was published online in November 2005 with corrections to the Cover Date.     

Evaluation of measurement uncertainty for analytical procedures using a linear calibration function

In the EURACHEM/CITAC draft ”Quantifying uncertainty in analytical measurement” estimations of measurement uncertainty in analytical results for linear calibration are given. In this work these estimations are compared, i.e. the uncertainty deduced from repeated observations of the sample vs. the uncertainty deduced from the standard residual deviation of the regression. As a result of this study it is shown that an uncertainty estimation based on repeated observations can give more realistic values if the condition of variance homogeneity is not correctly fulfilled in the calibration range. The complete calculation of measurement uncertainty including assessment of trueness is represented by an example concerning the determination of zinc in sediment samples using ICP-atomic emission spectrometry. Received: 9 February 2002 Accepted: 17 April 2002