Applications of control theory to economic analysis: J.D. Pitchford and S.J. Turnovsky,Editors, Amsterdam: North-Holland, 1977, 364 pages,Dfl. 155.00

A.K. Sen's index, P, is the only measure of poverty in a population that adequately allows for numbers in poverty, intensity of average poverty, and income distribution among the poor, while respecting two natural axioms. Nevertheless, the derivatives of P possess at least four attributes, at best highly counter-intuitive, at worst inconsistent with diminishing-marginal-utility assumptions, underlying the axioms themselves. Due to problems in handling income distribution among the poor, no measure of aggregate poverty can be constructed. Instead, it is proposed to construct a simple measure of those in ultra-poverty - among whom income cannot be very unequal - plus a pair of measures of moderate poverty.     

A numerical study of expected accuracy and precision in Calibration-Free Laser-Induced Breakdown Spectroscopy in the assumption of ideal analytical plasma

Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS) has been proposed several years ago as an approach for quantitative analysis of Laser-Induced Breakdown Spectroscopy spectra. Recently developed refinement of the spectral processing method is described in the present work. Accurate quantitative results have been demonstrated for several metallic alloys. However, the degree of accuracy that can be achieved with Calibration-Free Laser-Induced Breakdown Spectroscopy analysis of generic samples still needs to be thoroughly investigated. The authors have undertaken a systematic study of errors and biasing factors affecting the calculation in the Calibration-Free Laser-Induced Breakdown Spectroscopy spectra processing. These factors may be classified in three main groups: 1) experimental aberrations (intensity fluctuations and inaccuracy in the correction for spectral efficiency of a detection system), 2) inaccuracy in theoretical parameters used for calculations (Stark broadening coefficients and partition functions) and 3) plasma non-ideality (departure from thermal equilibrium, spatial and temporal inhomogeneities, optical thickness, etc.). In this study, the effects of experimental aberrations and accuracy of spectral data were investigated, assuming that the analytical plasma is ideal. Departure of the plasma conditions from ideality will be the object of future work. The current study was based on numerical simulation. Two kinds of metallic alloys, iron-based and aluminum-based, were studied. The relative weight of the error contributions was found to depend on the sample composition. For the here-investigated samples, the experimental aberrations contribute to the overall uncertainty on the quantitative results more than theoretical parameters. The described simulation method can be applied to the Calibration-Free Laser-Induced Breakdown Spectroscopy analysis of any other kind of sample.     

Broadening and shifting of the 321-, 325- and 380-GHz lines of water vapor by pressure of atmospheric gases

Three spectral lines of the main water molecule isotope in the ground vibrational state located near 321, 325 and 380 GHz were studied at low pressures and room temperature using spectrometer with radio-acoustic detection of absorption. Self-, N₂- and O₂-pressure broadening and shifting parameters of these lines have been precisely measured. A number of parameters, in particular pressure shifts, were obtained for the first time. Complementary study of the 325-GHz line by resonator spectrometer at atmospheric pressure validated the low pressure experiment data and allowed measurement of the 325-GHz line intensity. Obtained results are discussed in comparison with previous experimental and theoretical data.     

Population replications and ethical poverty measurement

In this paper, a class of relative and a class of absolute ethical measures of poverty depending on the head-court ratio and the aggregate income gap of the poor are characterized. Among other requirements, an axiom for poverty comparisons of distributions of different dimensions is used. Furthermore, it is shown that the above-mentioned axiom for population change cannot be used to characterize a specific class of absolute ethical poverty indices depending on the absolute number of poor instead of the head-count ratio.     

铁的理化特性对测定铁的精密度和准确度的影响

通过对铁的理化特性分析，实验设计和观察及借助数理统计分析，从根本上解释和解决水中总铁的测定精密度不好的问题。     

应用灰色系统模型提高仪器精度

文中介绍了灰色系统的原理及建模方法 ,并把它与测量仪器的使用结合起来 ,提出一种提高测量精度的新方法。实验结果证明了此方法的经济性和有效性。     

Revisiting type-A uncertainties relating to the measurement of mass fraction of lead using isotope-dilution inductively coupled plasma mass spectrometry: a way of improving measurement precision and expanded uncertainty

A quadrupole inductively coupled plasma mass spectrometer (Q-ICP-MS) has been used for determination of lead in plant materials using isotope-dilution inductively coupled plasma mass spectrometry. The accuracy of the method was demonstrated by analysis of a matrix certified reference material, NIST SRM 1547 Peach Leaves. Specific instrumental parameters of Q-ICP-MS, including isotope analysis mode, integration time per point, number of points per mass, and number of measurements, were optimized to obtain the best measurement precision. The precision (expressed as relative standard deviation) associated with replicate measurement of the ²⁰⁸Pb/²⁰⁶Pb isotope ratio and its mass-bias correction factor was <0.2%. Following “Example A7” of the Eurachem/CITAC Guide, the relative expanded uncertainty, U _rel, (coverage factor k = 2) was found to be ±1.1%, which fulfilled the target value of ±2% maximum and was lower than the uncertainty of ±3.4% reported by NIST based on isotope-dilution thermal ionization mass spectrometry. Sample recovery of 99% was obtained.     

Spiroligomer-Based Macrocycles for Atomically Precise Membranes

Here, we report a new class of peptidomimetic macrocycles with well-defined three-dimensional structures and low conformational flexibility. They are assembled from fused-ring spiro-ladder oligomers (spiroligomers) by modular solid-phase synthesis. Two-dimensional nuclear magnetic resonance confirms their shape persistency. Triangular macrocycles of tunable sizes assemble into membranes with atomically precise pores, which exhibit size and shape-dependent molecular sieving towards a series of structurally similar compounds. The exceptional structural diversity and stability of spiroligomer-based macrocycles will be explored for more applications.     

Understanding the meaning of accuracy,trueness and precision

Clear definitions of basic terms, used to describe the quality of measurements, is essential for communication among scientists as well as when reporting measurement results to clients. Even if appropriate definitions are given in international standards and guidelines, the understanding of some basic terms sometimes proves difficult. The reasons for this are various, e.g., the same words being defined rather differently in encyclopaedias and in international standards as well as concepts, well established in some languages, that may be relatively new in other national communities and at large in the international one. Here we present a matrix intended to clarify the relationships between the type of error affecting an analytical measurement, the respective qualitative concepts (performance characteristics) and their quantitative expression.

Purity of potassium hydrogen phthalate, determination with precision coulometric and volumetric titration--a comparison

The mass fraction of potassium hydrogen phthalate (KHP) from a specific batch was certified as an acidimetric standard. Two different analytical methods on a metrological level were used to carry out certification analysis: precision constant current coulometric and volumetric titration with NaOH. It could be shown that with a commercial automatic titration system in combination with a reliable software for the end-point detection it is possible to produce equivalent results with the same accuracy in comparison to a definite method handled by a fundamental apparatus for traceable precision coulometry. Prerequisite for titrations are that a high number of single measurement are applied which are calibrated with a high precision certified reference material.