Evaluation of uncertainty utilising the component by component approach

 This paper reviews the so-called "component by component approach" of evaluating measurement uncertainty. An overview of the evaluation process is given followed by an in-depth discussion of some of the differences between this approach and the approach of utilising validation data. Some of the advantages and disadvantages of using the component by component approach are outlined at the end. Received: 4 August 1999 · Accepted: 11 November 1999     

Interaction of dispersed phase with concentration polarization

The effect of a dispersed phase in reducing the concentration polarization in a membrane tube has been studied. The presence of a dispersed phase seems to have an effect in controlling the size of eddy formation and the rate of energy dissipation in the fluid medium. The role of eddy length and the energy dissipation rate on the mass transfer coefficient is discussed. Theoretical results obtained for the mass transfer coefficient and for the concentration polarization in the case of gelatin ultrafiltration are compared with the existing experimental results. The theoretical predictions seem to be in good agreement with the experimentally observed results.     

NH4Cl作助熔剂合成CaS：Ce的光谱特性及其浓度效应

以ＮＨ４Ｃｌ作助溶剂，碳还原硫酸钙的方法合成了ＣａＳ：Ｃｅ。在紫外光激发下，ＣａＳ：Ｃｅ中存在着Ｃｅ＾３＋的＾２Ｄ－＾２Ｆ５／２（５００ｎｍ）和＾２Ｄ－＾２Ｆ７／２（５５０ｎｍ）跃迁发射，但在蓝色光激发下，只有波峰为５３２ｎｍ半宽度为９２ｎｍ的宽带发射。当Ｃｅ＾３＋的浓度为０．０７５ｍｏｌ％时，＾２Ｄ－＾２Ｆ５／２跃迁发射强度与＾２Ｄ－＾２Ｆ７／２跃迁发射强度相等，而５３２ｎｍ发射猝灭。     

巯基棉富集─火焰原子吸收分光光度法测定水中的微量铁

本文详细考查了巯基棉富集Ｆｅ（Ⅲ）的条件，发现微量铁（Ⅲ）在ｐＨ值为５－８的条件下能为巯基棉定量吸附．１ｍｏｌ／Ｌ盐酸５ｍＬ能将巯基棉吸附的Ｆｅ（Ⅲ）定量洗脱，０．１ｇ巯基棉的饱和吸附量为９０μｇ，样品分析测定结果的相对标准偏差小于３．４％，９８．４％－９８．８％。     

Spike solutions of a nonlinear Schrödinger equation with degenerate potential

We study the existence of positive solutions to the elliptic equation ε²Δu(x,y)−V(y)u(x,y)+f(u(x,y))=0 for (x,y) in an unbounded domain subject to the boundary condition u=0 whenever is nonempty. Our potential V depends only on the y variable and is a bounded or unbounded domain which may coincide with . The positive parameter ε is tending to zero and our solutions u_ε concentrate along minimum points of the unbounded manifold of critical points of V.     

Voice field measurements—a new method of examination: the influence of hearing on the human voice

There are various methods to evaluate voice parameters. Original software was used to assess the voice quality by the staff of AUDIO-Fon centr Brno, Czech Republic. A group of hereditary deaf persons was examined. Deaf persons have all of the biological conditions to make voice except for the possibility of acoustic feedback. We examined the voices of 35 persons (20 men and 15 women) with hereditary profound hearing impairments, and we compared voice parameters with the voice of intact persons. To measure we used special software called voice field measurements (VFMs). The program graphically records voice frequency and intensity. VFM is an objective method that enables the assessment of basic physical voice characteristics. It is suitable for the examination of both intact and disturbed voice. The voice of the deaf has a higher basic voice frequency in men as well as in women. This type of voice production, ie, childlike voice, which is fixed only by a motor stereotype, is much more demanding for a mature larynx. Hearing influences both the voice development and speech production. The voice of persons with hearing impairments has a higher basic voice frequency regardless of their sex. This type of voice production, which is fixed only by a motor stereotype, ie, child voice, is much more demanding for a larynx of an adult. Thus, phonation of deaf people is more demanding and their voice production needs greater effort. Deaf people, despite an intact phonic apparatus, cannot produce more than one type of voice. They cannot modulate their voices concerning the frequency and dynamics. They cannot change their voices continually. The voice is limited in both of these parameters (frequency and dynamics). If a deaf person wants to change a voice characteristic, it is possible only by discontinuous changes-"skipping."     

Traceability without uncertainty: current situation in the pharmaceutical industry

The current situation in the pharmaceutical industry is discussed, when the traceability of measurement (analytical) results to certified values of pharmacopoeial reference standards is required, without evaluating their uncertainties. It is shown that the evaluation of measurement uncertainty is necessary for understanding the level of confidence of the analytical results and their comparability, particularly during preparation and characterisation of the reference standards.Papers published in this section do not necessarily reflect the opinion of the Editors, the Editorial Board and the Publisher. Apart from exceptional circumstances, they are not submitted to the usual referee procedure and go essentially unaltered.     

掺Yb3+氧化镧钇透明激光陶瓷的光谱特性

采用传统陶瓷烧结工艺,在无压还原气氛下低温制备出透明性良好的掺Yb3+氧化镧钇透明激光陶瓷,测试了其在室温下的吸收光谱、发射光谱和荧光寿命.结果表明,掺Yb3+氧化镧钇透明激光陶瓷的吸收系数随着Yb3+掺杂浓度的增加而增大,最强吸收峰974nm处的吸收截面为0.90～1.12×10－20 cm2;主发射峰1 032 nm和1 075 nm处的发射截面分别为1.05×10－20 cm2和0.87×10－20 cm2; Yb3+掺杂浓度为5at.%时荧光寿命为1.38 ms,并随Yb3+掺杂浓度的增加而减小;当Yb3+掺杂浓度超过10at.%时,样品中存在严重的浓度猝灭.产生浓度猝灭的原因是高掺杂时离子间存在合作上转换和能量转移.     

Fluorescence enhancement of oxide fluoride glass co-doped with TbF3 and SmF3

The fluorescence property of xTbF₃-BaF₂-AlF₃-GeO₂+ySmF₃ (x=0.01-40 mol%, y=0-5 wt%) glasses were investigated. The enhancement of Sm³⁺ fluorescence was recognized in the presence of Tb³⁺. Increasing Tb³⁺ content, the emission color changed from green to orange. When the intensity of fluorescence at 540 nm originated from Tb³⁺ is compared with that at 600 nm originated from Sm³⁺, the information about the concentration quenching of Tb³⁺ and Sm³⁺ was obtained. From these results, rare earth ions were dispersed identically in the glasses. After heating to 673 K or cooling to 77 K, the emission color of 20TbF₃-20BaF₂-10AlF₃-50GeO₂/mol%+0.05 wt% SmF₃ glass was reversibly changed from orange to green. In addition, while the emission from 10TbF₃-20BaF₂-10AlF₃-60GeO₂+0.01 wt% SmF₃ glass was green, its crystallized sample, prepared by annealing at 1073 K, exhibited an orange emission due to Sm³⁺ at room temperature.