Characterization of the multivariate Gauss-Markoff model with singular covariance matrix and missing values

The aim of this paper is to characterize the Multivariate Gauss-Markoff model (MGM) as in (2.1) with singular covariance matrix and missing values. MGMDP2 model and completed MGMDP2Q model are obtained by three transformations D, P and Q (cf. (3.21)) of MGM. The unified theory of estimation (Rao, 1973) which is of interest with respect to MGM has been used.The characterization is reached by estimation of parameters: scalar ² and linear combination as in (4.8), (4.6), (4.7) as well as by the model of the form (5.1) (cf. Th. 5.1). Moreover, testing linear hypothesis in the available model MGMDP2 by test function F as in (6.3) and (6.4) is considered.It is known (Oktaba 1992) that ten quantities in models MGMDP2, and MGMDP2Q are identical (invariant). They permit to say that formulas for estimation and testing in both models are identical (Oktaba et al., 1988, Baksalary and Kala, 1981, Drygas, 1983).An algorithm and the UMGMBO program for calculations concerning estimation and testing in MGM have been presented by Oktaba and Osypiuk (1993).     

汝瓷及其仿制品瓷釉的显微结构分析和"汝钧不分"难题的破解

使用扫描电镜（SEM）、紫外-可见分光光度计（UV-VIS）和色差计分析了一些汝官瓷、仿汝瓷和钧瓷残片.在SEM下,汝瓷与钧瓷的显微结构差异较大,而仿汝瓷的显微结构类似于钧瓷;瓷釉中分相或者析晶导致的Rayleigh散射和Mie散射作用都对其釉色存在贡献;三者显微结构上的差异可用来解释它们反射光谱上的差异.UV-VIS可用于解决“汝钧不分”的问题,并为汝瓷的无损科技鉴定提供了可靠的依据.     

A novel photochromic fulgide based on porphyrin for nondestructive information processing

A fulgide connected to porphyrin (FUL-TPP) can transform its open isomer to closed isomer upon the irradiation with UV or visible light. Herein, they can be used to write binary data. Furthermore, the open form can emit luminescence but the closed cannot form while irradiated in another light that will not cause the optical chemical reaction. Therefore, the data can be read out without destruction.     

Fractional factorial design based microwave‐assisted extraction for the determination of organophosphorus and organochlorine residues in tobacco by using gas chromatography—mass spectrometry

Sample preparation is often the main bottleneck in analyzing biological samples. Particularly, effective evaluation of sample preparation conditions usually involves multiple factors and tedious and time‐consuming experiments. In this study, fractional factorial design, specifically orthogonal array testing, was employed to screen and optimize multiple extraction parameters in concise but representative experiments. An efficient and sensitive method was developed to determine organophosphorus and organochlorine pesticide residues in tobacco, via microwave‐assisted extraction and gas chromatography coupled with mass spectrometry detection. With orthogonal array design, screening, and optimization tests were subsequently conducted to determine the range, impact rank, and possible interactions of extraction temperature, time, microwave power, additive salt, and additive water. Orthogonal array testing selectively reduces the size and cost of experiments and meanwhile provides more information compared to the traditional experimental design that optimizes one factor at a time. A good linear range (0.02–2.00 μg/mL), limits of detection (0.001–0.098 μg/mL), and recovery rates (70.4–107.1%) were demonstrated by spiking known concentrations of multiple pesticide standards in tobacco samples. The established method was then successfully applied to the determination of multipesticide residues in raw tobacco leaves and commercial cigarettes.     

On embedding a cycle in a plane graph

Consider a planar drawing Γ of a planar graph G such that the vertices are drawn as small circles and the edges are drawn as thin stripes. Consider a non-simple cycle c of G. Is it possible to draw c as a non-intersecting closed curve inside Γ, following the circles that correspond in Γ to the vertices of c and the stripes that connect them? We show that this test can be done in polynomial time and study this problem in the framework of clustered planarity for highly non-connected clustered graphs.     

The effect of thermo-oxidation on the mechanical behaviour of polymer epoxy materials

This paper focuses on the employment of instrumented Ultra-Micro Indentation (UMI) and Confocal Interferometric Microscopy (CIM) for investigating the effect of thermo-oxidation on the local mechanical behaviour of two polymer materials. The UMI curves give good indication of the local short-time behaviour, while the CIM observation of the indentation prints and their recovery during time provides some information about the long-time behaviour. For both studied epoxy resins, this experimental approach reveals significant modification of the local mechanical behaviour with oxidation level.     

Liquid sheet disintegration at high pressure: An experimental approach

The primary atomization was studied in a 300 μm thickness water sheet, generated by a planar airblast atomizer. The research novelty consisted in increasing the airflow absolute pressure from atmospheric conditions to 6 bar. The experimental techniques employed included Oscillometry by Laser Intensity Reflexion (ORIL), Laser Doppler Velocimetry (LDV) and flow visualization by fast video camera. The atomization mechanisms, described in the literature at atmospheric environments, were observed at high pressure conditions, for a constant momentum flux ratio. Furthermore, a new atomization mechanism was observed at high values of this ratio. Finally, dimensionless relations have been proposed for the global oscillation frequency, minimum air oscillation velocity, break-up distance and transversal wavelength. To cite this article: V.G. Fernandez et al., C. R. Mecanique 337 (2009).     

用步进应力加速寿命试验法分析爆炸螺栓的可靠性

本文通过对爆炸螺栓进行步进应力加速寿命试验分析 ,得到爆炸螺栓可靠寿命的估计 ,从而确定爆炸螺栓的可靠性     

Analytical and Experimental Analysis of Wing Rock

The paper deals with the study of an analytical model of wingrock, based on parameter identification of experimental data. Theexperiments were performed in the Aeronautical Laboratory of Politecnicodi Torino, in the D3M Low Speed Wind Tunnel, on a80° delta wing. Free-to-roll tests have been used todetermine build-up and limit cycle characteristics of wing rock. Flowvisualization techniques were also utilized in order to track vortexpositions. The characteristics of the limit cycle (oscillation amplitudeand frequency) were compared in detail with reference results obtainedin other laboratories. An analytical nonlinear model was derived.Parameters were identified by means of the least-squares approximationof experimental data with coherent initial conditions. The consistencyof time histories, reproduced by numerical integration, was alsoanalyzed. This formulation correctly predicts stable limit cycles for awide range of airspeeds, angles of attack and release roll angles.     

Development of high-temperature microsample testing

Microsample tensile testing has been established as a means of evaluating the room temperature mechanical properties of specimens with gage sections that are tens to hundreds of microns thick and several hundred microns wide. The desire to characterize the mechanical response of materials at elevated temperatures has motivated the development of high-temperature microsample testing that is reported here. The design of specially insulated grips allows the microsamples to be resistively heated using approximately 2 V DC and currents ranging between 2 to 6 A. An optical pyrometer with nominal spot size of 290 μm and 12 μm diameter type K thermocouples was employed to measure and verify the temperature of the microsamples. The ability of the pyrometer to accurately measure temperature on microsamples of different thicknesses and with slightly different emissivities was established over a temperature range from 400°C to 1100°C. The temperature gradient along the length and thickness of the microsample was measured, and the temperature difference measured in the gage section used for strain measurements was found to be less than 6.5°C. Examples of elevated temperature tensile and creep tests are presented.