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91.
Stanisaw Gnot Ewaryst Rafajowicz Agnieszka Urbaska-Motyka 《Annals of the Institute of Statistical Mathematics》2001,53(2):370-379
In the paper we consider a random linear model for observations provided by spatially located sensors measuring signals coming from one source. For this model a set of sufficient and complete statistics are found, and it is shown that the maximum likelihood estimators of unknown parameters (characteristics of the source) are functions of those statistics. The problem of nonnegative estimators of variance components of the model is shortly discussed. Comparisons of the mean squared errors of several estimators are given. Numerical example concerning hunting for defects in solar cells is considered in details. 相似文献
92.
Oxidative-reductive properties on the acid-base surfaces of the oxide compositions Sn-Ce-Rh-O and Zr-Mg-Y-O, active as catalysts in the ketonization of secondary alcohols were determined based on the isopropanol conversion selectivity. The kinetics of isopropanol conversion was measured in the oxygen-free atmosphere. Activation energies for both directions of conversion (dehydration to propylene and dehydrogenation to acetone) were calculated. The results were compared with the kinetics over SnO2 and ZrO2. Both oxide compositions, Sn-Ce-Rh-O and Zr-Mg-Y-O are oxidative-reductive catalysts containing Lewis acid centers. 相似文献
93.
94.
Bogusław Buszewski Agnieszka Ulanowska Tomasz Ligor Natalia Denderz Anton Amann 《Biomedical chromatography : BMC》2009,23(5):551-556
In this study, 38 samples of expired air were collected and analyzed from 20 non‐smoking volunteers, four passive smokers and 14 smokers (21 women and 17 men). Measurements were carried out using solid‐phase microextraction (SPME) as an isolation and preconcentration technique. The determination and identification were accomplished by gas chromatography coupled with mass spectrometry (GC/MS). Our data showed that ca 32% of all identified compounds in the breath of healthy non‐smokers were saturated hydrocarbons. In the breath of smoking and passive smoking volunteers hydrocarbons were predominant, but also present were more exogenous analytes such as furan, acetonitrile and benzene than in the breath of non‐smokers. Acetonitrile, furan, 3‐methylfuran, 2,5‐dimethylfuran, 2‐butanone, octane and decane were identified in breath of smoking and passive smoking persons. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
95.
96.
This paper proposes a method for solving optimisation problems involving piecewise quadratic functions. The method provides a solution in a finite number of iterations, and the computational complexity of the proposed method is locally polynomial of the problem dimension, i.e., if the initial point belongs to the sufficiently small neighbourhood of the solution set. Proposed method could be applied for solving large systems of linear inequalities. 相似文献
97.
Anna Śmiechowska Witold Przychodzeń Jarosław Chojnacki Piotr Bruździak Jacek Namieśnik Agnieszka Bartoszek 《Structural chemistry》2010,21(5):955-964
Adducts of natural allyl, phenethyl, and benzyl isothiocyanates and 2-amino-1-methylbenzimidazole were synthesized. After
optimization of the reaction conditions, the target 2-benzimidazolylthioureas were obtained in reasonable yields. The detailed
molecular and crystal structures of these compounds were characterized by spectroscopic and X-ray methods. Spectral analysis
demonstrated that N-(1-methylbenzimidazolyl)-N′-allylthiourea, N-(1-methylbenzimidazolyl)-N′-benzylthiourea, and N-(1-methylbenzimidazolyl)-N′-phenethylthiourea exist in solution in an unprecedented three tautomeric forms, whose structures were corroborated unambiguously. 相似文献
98.
Agnieszka Czapik Maria Gdaniec 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(7):o356-o360
2,3,5,6‐Tetrafluorobenzene‐1,4‐diol easily forms cocrystals with heteroaromatic bases containing the pyrazine unit. In the 1:1 complexes with pyrazine, C6H2F4O2·C4H4N2, (I), and quinoxaline, C6H2F4O2·C8H6N2, (II), the crystal components are linked via O—H...N hydrogen bonds into one‐dimensional chains. With the largest base, phenazine, the 1:2 benzenediol–phenazine complex, C6H2F4O2·2C12H8N2, (III), was obtained, with the molecules linked via O—H...N interactions into a discrete heterotrimer. In all three cocrystals, the two types of molecules are organized into layers via softer C—H...O and C—H...F interactions and π–π stacking interactions, with stronger hydrogen bonds linking molecules of adjacent layers. In (II) and (III), molecules are arranged into heterostacks, whereas in (I) separate stacks are formed by the heterocyclic base and the benzenediol molecule. 相似文献
99.
We consider problems of the calculus of variations on unbounded time scales. We prove the validity of the Euler–Lagrange equation
on time scales for infinite horizon problems, and a new transversality condition. 相似文献
100.
Kamila Malecka Iwona Grabowska Jerzy Radecki Anna Stachyra Anna Góra‐Sochacka Agnieszka Sirko Hanna Radecka 《Electroanalysis》2012,24(2):439-446
The working principle of a genosensor is based on the mechanism of ion‐channel mimetic sensors. The analytical signals generated upon hybridization processes were recorded by a redox active marker [Fe(CN)6]3?/4? present in the sample solution using voltammetric techniques. The developed genosensor was suitable for determination of 20‐mer complementary oligonucleotide sequence, and also of the PCR products containing the complementary 20‐mer sequence in various positions, with detection limits in the 10 pM range. The noncomplementary 20‐mer oligonucleotide sequence as well as the PCR product without complementary region generated very weak response. The good discrimination of the position of the complementary part in the PCR products was observed. 相似文献