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81.
Carmen-Mihaela Popescu Iuliana Spiridon Carmen Mihaela Tibirna Cornelia Vasile 《Journal of photochemistry and photobiology. A, Chemistry》2011,217(1):207-212
A series of experiments were carried out to investigate photodegradation of lime wood (Tilia cordata Mill.) during artificial UV/Vis light irradiation for 600 h. Photodegradation of the wood samples was evaluated by thermogravimetry throughout the irradiation period at an interval of 100 h.The alteration of wood was observed by means of the peak temperatures of DTG variation and by the mass losses observed during heating, evaluated on the basis of the measured thermal data. The results obtained indicate a shifting of the DTG maxima to lower temperatures which may be related to the decreasing in the stability components during photodegradation. The values of the overall activation energies corresponding of the decomposition process progressively decreases.The decreased temperatures decomposition processes, weight losses and integral area of the peaks assigned to lignin, the increased integral area of the peaks assigned to hemicelluloses could be explained by new formed structures, mainly due to formation of reactive species. 相似文献
82.
Yoshihiko Maesono Spiridon Penev 《Annals of the Institute of Statistical Mathematics》2013,65(1):167-189
We derive the Edgeworth expansion for the studentized version of the kernel quantile estimator. Inverting the expansion allows us to get very accurate confidence intervals for the pth quantile under general conditions. The results are applicable in practice to improve inference for quantiles when sample sizes are moderate. 相似文献
83.
Vasilica Pascariu Ovidiu Avadanei Paul Gasner Iuliana Stoica Andrea P. Reverberi Liliana Mitoseriu 《Phase Transitions》2013,86(7):715-725
The preparation and properties of compositionally graded PbTiO3 (PT)–epoxy resin (EPR) composite thick films are reported in this study. Various graded specimens were prepared using gravity casting method by embedding PT powders into the EPR matrix. The existence of a graded structure with two distinct phases, a good intermixing, some air pores, and different morphologies, was confirmed by scanning electron microscopy micrographs. The dielectric constants of these composites have values in the range 5–12 at the frequency of ~104?Hz and about 3–13 at ~5?×?108?Hz. The composites with permittivity gradient act as a natural impedance match system in the frequency range 2–4?GHz, resulting in very low reflections. Therefore, the compositionally graded PT–EPR composite thick films are suitable as adapting impedance materials for microwave applications. 相似文献
84.
Choosing a suitable risk measure to optimize an option portfolio’s performance represents a significant challenge. This paper is concerned with illustrating the advantages of Higher order coherent risk measures to evaluate option risk’s evolution. It discusses the detailed implementation of the resulting dynamic risk optimization problem using stochastic programming. We propose an algorithmic procedure to optimize an option portfolio based on minimization of conditional higher order coherent risk measures. Illustrative examples demonstrate some advantages in the performance of the portfolio’s levels when higher order coherent risk measures are used in the risk optimization criterion. 相似文献
85.
Rauschenberger Armin Ciocănea-Teodorescu Iuliana Jonker Marianne A. Menezes Renée X. van de Wiel Mark A. 《Advances in Data Analysis and Classification》2020,14(3):571-588
Advances in Data Analysis and Classification - This paper introduces the paired lasso: a generalisation of the lasso for paired covariate settings. Our aim is to predict a single response from two... 相似文献
86.
Iuliana Sebarchievici Anca Lascu Gheorghe Fagadar-Cosma Anca Palade Ionela Fringu Mihaela Birdeanu Bogdan Taranu Eugenia Fagadar-Cosma 《Comptes Rendus Chimie》2018,21(3-4):327-338
The developments concerning new hybrids based on porphyrin derivatives and colloids destined for the detection of ascorbic acid (AA) in the relevant range for medical investigations are presented. Mn(III) tetratolylporphyrin chloride (MnTTPCl), spherical gold colloid (n-Au), and their hybrid (MnTTPCl/n-Au) were chosen to be comparatively investigated by ultraviolet–visible spectroscopy in the presence of AA. The hybrid material (MnTTPCl/n-Au) has the best capacity to detect concentrations of AA in the range of 2.6 × 10?6–4.38 × 10?5 M. Modified glassy carbon (GC) electrodes were obtained by thin film deposition of MnTTPCl, n-Au alone, and in successive mixed thin films, comparing their response during the electrochemical oxidation of AA. The electrocatalytic effect of the MnTTPCl on the AA oxidation is justified both by the increase in the peak current density and by the shift toward more negative potentials (0.024 V). The GC/MnTTPCl electrode has the best electrocatalytic effect for the AA oxidation and is promising for sensor applications. 相似文献
87.
Marcus Frings Iuliana Atodiresei Dr. Jan Runsink Dr. Gerhard Raabe Prof. Dr. Carsten Bolm Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(7):1566-1569
In control : A new catalytic vinylogous Mukaiyama aldol reaction provides products with high diastereo‐ and enantioselectivities (up to 99 % de and ee; see scheme). The relative and absolute stereochemistry of a representative product was rigorously assigned by NMR and CD spectroscopies (measured and calculated), X‐ray diffraction, and quantum‐chemical calculations.
88.
Konstantinos Theofilatos Grigorios Beligiannis Spiridon Likothanassis 《Journal of Computational and Applied Mathematics》2009
In the present contribution, a novel method combining evolutionary and stochastic gradient techniques for system identification is presented. The method attempts to solve the AutoRegressive Moving Average (ARMA) system identification problem using a hybrid evolutionary algorithm which combines Genetic Algorithms (GAs) and the Least Mean Squares LMS algorithm. More precisely, LMS is used in the step of the evaluation of the fitness function in order to enhance the chromosomes produced by the GA. Experimental results demonstrate that the proposed method manages to identify unknown systems, even in cases with high additive noise. Furthermore, it is observed that, in most cases, the proposed method finds the correct order of the unknown system without using a lot of a priori information, compared to other system identification methods presented in the literature. So, the proposed hybrid evolutionary algorithm builds models that not only have small MSE, but also are very similar to the real systems. Except for that, all models derived from the proposed algorithm are stable. 相似文献
89.
Dimitrios Tsolis Spiridon Nikolopoulos Lambros Drossos Spyros Sioutas Theodore Papatheodorou 《Journal of Computational and Applied Mathematics》2009
The current work is focusing on the implementation of a robust multibit watermarking algorithm for digital images, which is based on an innovative spread spectrum technique analysis. The paper presents the watermark embedding and detection algorithms, which use both wavelets and the Discrete Cosine Transform and analyzes the arising issues. 相似文献
90.
Laura C. E. Manoliu Eliza C. Martin Adina L. Milac Laurentiu Spiridon 《Molecules (Basel, Switzerland)》2021,26(16)
Alzheimer’s disease is a neurodegenerative disorder incompatible with normal daily activity, affecting one in nine people. One of its potential targets is the apelin receptor (APJR), a G-protein coupled receptor, which presents considerably high expression levels in the central nervous system. In silico studies of APJR drug-like molecule binding are in small numbers while high throughput screenings (HTS) are already sufficiently many to devise efficient drug design strategies. This presents itself as an opportunity to optimize different steps in future large scale virtual screening endeavours. Here, we ran a first stage docking simulation against a library of 95 known binders and 3829 generated decoys in an effort to improve the rescoring stage. We then analyzed receptor binding site structure and ligands binding poses to describe their interactions. As a result, we devised a simple and straightforward virtual screening Stage II filtering score based on search space extension followed by a geometric estimation of the ligand—binding site fitness. Having this score, we used an ensemble of receptors generated by Hamiltonian Monte Carlo simulation and reported the results. The improvements shown herein prove that our ensemble docking protocol is suited for APJR and can be easily extrapolated to other GPCRs. 相似文献