The influence of radon measurement errors on the uncertainties of epidemiological case-control studies

To analyse the influence of the parameters of case and control groups and uncertainties of radon concentration assessments on the dose-effect dependence, a special computer program was designed. The influence of measurement errors on the uncertainties of radon case-control analysis is demonstrated on examples of hypothetical case and control groups with sizes from 250-500 to 7000-14,000 members. The modelling was conducted using a Monte Carlo technique for different values of measurement uncertainties. The random errors of radon assessment affect both the numerical value of the slope coefficient β of the linear dependence of relative risk of lung cancer incidence on indoor radon concentration and the accuracy of this value. The extrapolation of the dependence of the slope coefficient β on the total (initial plus additional) random error of radon concentration assessment is suggested for the assessment of an unbiased value of the slope coefficient β.     

激光辐射下的固体双基推进剂的燃烧特性

燃速与辐射通量之间的关系可以由两支相交直线构成的线性方程进行描述,其中折点(交点)是外界辐射能作用下固体双基推进剂燃烧的一个重要特征。包括折点附近在内的燃烧特性可以采用Fourier方程进行分析。考虑到辐射在燃烧表面上形成的碳化层对辐射传递的阻碍作用,本文分析了1040,1041,N-5和N型推进剂的燃烧特性。导致两段函数和折点形成的主要原因是在辐射能到达凝聚相表面之前部分辐射能已经发生了损失。     

Millimeter wave band open resonators with additional restriction of resonant space

Electromagnetic characteristics of open resonators with a bounded region beside one of the mirrrs are presented. The unknown previously modes are studied and classified. It is the quasi-fundamental modes, associated modes and echelette-echelette oscillations. This result may be used for the applicaiton in the elaboration of oscillation systems of mm-wave devices.     

The theory of search from a statistical viewpoint

Summary The statistical approach to search is a subject which interfaces with many other fields. This work continues a series of papers which studies these relationship with special emphasis on geometric problems in non-sequential search. A targetT is sought using a series of testsX ₁,X ₂.... From each test there is an observationY _i=f(X _i , θ), where θ is an unknown parameter andT=T(θ). Spacing theories and the theories of Voronoi regions can be used to represent the solutions to Bayes and entropy-based formulations to the search problem by partitioning the search field intoconsistent regions where the target is known to lie, given the observations. Other examples are from integration where the target is a function. Covering theory is studied and the last section gives a brief comparison with a sequential approach. Read before the Spanish Statistical Society at a meeting organized by the Universidad de Almería on Friday, April 29, 1994     

Concentration dependence of thermodynamic interaction parameters in a polymer-polymer-solvent system

Summary The concentration dependence of Thermodynamic Interaction Parameters is reported for the system Polystyrene (PS, M_{W 3}=4.4 · 10⁵) — Polybutylmethacrylate (PBMA, M_{W 2}=2.7 · 10⁵) — CCl₄.     

Volt-Watt Sensitivity of Semimetal <Emphasis Type="Italic">BiSb</Emphasis> Film Thermocouple Sensors in the 8 mm Wavelength Range

The paper considers the experimental and analytical data on volt-watt characteristics of metal-semimetal BiSb film point contacts in 8 millimeter wavelength range. Analytical expressions have been obtained for the volt-watt sensitivity and the resistance of the metal-semimetal BiSb film point contacts. A thermoelectric millimeter wave range detector has been designed on the basis of the sensors; the performance is illustrated by experimentally determined volt-watt relations.     

Cross-correlation frequency-resolved optical gating for studying ultrashort-pulse nonlinear dynamics in arbitrary fibers

We describe a cross-correlation frequency-resolved optical-gating system specifically designed for studying nonlinear pulse-propagation dynamics in fibers of arbitrary length at telecommunication wavelengths. The formation of optical solitons and the appearance of temporal phase slips are observed in 100 m of fiber. The wide phase-matching bandwidth and high sensitivity of this system allow us to visualize femtosecond-pulse evolution in a range of linear and nonlinear propagation regimes.     

Mode propagation in optical nanowaveguides with dielectric cores and surrounding metal layers

The mode spectrum in an optical nanowaveguide consisting of a dielectric-core layer surrounded by two identical metal layers is investigated. A simple model based on mode matching to predict the properties of mode propagation in such optical nanowaveguides is proposed. It is shown that quasi-TM00 and quasi-TM10 modes supported by an optical microstrip line do not have a cutoff frequency, regardless of the size of the metal strips, the thickness of the dielectric slab, and the cross-sectional shape. The transverse size of the TM00 mode supported by a nanosized microstrip line was found to be approximately equal to the transverse dimension of the microstrip line. In closed rectangular and elliptical nanowaveguides, i.e., in which all dielectric surfaces are covered with metal films, the cross-sectional shape of the waveguide should be stretched along one side to produce propagation conditions for the fundamental mode.