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1.
The problem of finding minima of weakly sequentially lower semicontinuous functions on reflexive Banach spaces is studied by means of convex and nonconvex subdifferentials. Finding a descent direction for a non-stationary point is a question of importance for many optimization algorithms. The existence or non-existence of such a direction is clarified through several theorems and a series of selective examples. For the general problem, a notion called radius of descent is proposed and shown to be useful for the analysis related to descent directions. 相似文献
2.
Apostol I. Damian V. Garoi F. Iordache I. Bojan M. Apostol D. Armaselu A. Morais P. J. Postolache D. Darida I. 《Optics and Spectroscopy》2011,111(2):287-292
Laser material removal applied to selective overpaintings and subsequent painting layers detachment was studied in order to
select the best cleaning practice of painted artworks. The ablation depth as a function of incident laser fluence/intensity
and irradiation pulse number was considered as a reference parameter. We have measured the ablation depth with both a contact
microprofilometer and a white light interferometer as a function of laser irradiation parameters. The measurements have evidenced
that the ablation depth in our experiments varied between 2 and 100 μm making possible selective removal of painting. 相似文献
3.
C. I. Postolache C. A. Simion I. I. Mihalcea 《Journal of Radioanalytical and Nuclear Chemistry》1999,241(1):33-35
Polyacrylic hydrogels were14C- and3H-labeled in three main steps. In the first one, the monomer as sodium salt was14C-labeled at the carboxyl group via the carbonation of vinylmagnesium bromide and [1-14C]acrylic acid was obtained, followed by labeling with tritium via isotopic exchange in heterogeneous catalysis. The monomer
was purified and its radiochemical purity was analyzed using TLC. In the last step, the hydrogel was obtained through radiopolymerization
of the doubly labeled monomer using a60Co source. The oligomers and unpolymerized monomers were eliminated from the hydrogel by swelling in water followed by dehydration
with methanol. 相似文献
4.
Scientific investigations of the Imperial Gates from the Petrindu wooden church,Salaj County,Romania 下载免费PDF全文
Olivia Florena Marutoiu Ioan Bratu Constantin Marutoiu Dana Luminita Postolache Mihai Dragomir Claudiu Tanaselia Sorina Garabagiu 《X射线光谱测定》2018,47(2):176-185
In order to preserve and restore the Imperial Gates from the Petrindu wooden church, Salaj County, Romania, (map location—latitude, longitude: 46.97, 23.19), the scientific investigation of the wooden support and painting materials (ground and pigments) was performed, employing Fourier‐transform infrared spectroscopy (FTIR), X‐ray fluorescence spectroscopy, and 3D scanning. FTIR spectroscopy offered information about the wooden degradation stage, whereas X‐ray fluorescence and FTIR spectroscopic methods were employed for structural painting materials characterization. The structural data can be correlated with the artistic, theological, and historical analysis of this religious patrimony object. After obtaining information about the wooden support and painting materials, the Imperial Gates were 3D digitized using state of the art laser scanning technology. The digital 3D model obtained was restored in a virtual environment and converted into an interactive 3D model that can be used for Romanian cultural heritage digital dissemination. 相似文献
5.
6.
Emanuel Postolache D. K. Powell G. Popov Ram C. Rai M. Greenblatt J. W. Brill 《Solid State Sciences》2000,2(8)
We have measured Young's modulus (using a vibrating reed technique) and the specific heat (using ac calorimetry) on the same crystals of α′-NaV2O5 at its Tc=34 K magnetic phase transition. Both properties exhibit large, unsymmetrical, and sample-dependent anomalies. While the specific heat results suggest tricritical behavior of the transition, large fluctuation effects are observed in the modulus above Tc. Fits of the modulus in terms of the specific heat, entropy, and free energy suggest that fluctuations are strongly stress- and sample-dependent. 相似文献
7.
In this paper we give a criterion for a given set K in Banach space to be approximately weakly invariant with respect to the differential inclusion x′(t) ∈ Ax(t) + F(x(t)), where A generates a C
0-semigroup and F is a given multi-function, using the concept of a tangent set to another set. As an application, we establish the relation
between approximate solutions to the considered differential inclusion and solutions to the relaxed one, i.e., x′(t) ∈ Ax(t) + [`(co)]\overline {co}
F(x(t)), without any Lipschitz conditions on the multi-function F. 相似文献
8.
L. Matei C. Tanase C. Postolache G. Bubueanu C. Podina 《Journal of Radioanalytical and Nuclear Chemistry》2009,280(2):325-328
Nandrolon is an androgenic growth promoter. This anabolic substance can be used for accelerating the increase of animal body
mass. This steroid is used also in the therapy of animals like cattle, sheep or hogs and it can be found as residuum in the
animal body. In a lot of countries this therapy is used abusively and, as result, results in a high level of residuals in
different food stuffs such as beef and pork meat and veal liver. Because of these potential health damages it is important
to monitor the food concerning the hormonal residuals. Due to their very low concentration in animal products, these chemical
compounds can be determined only using ELISA and RIA immunochemical analysis techniques. In this paper, we describe the methods
of obtaining tritium-labeled nandrolone for RIA kits production. 相似文献
9.
Memudu O. Olatinwo 《Central European Journal of Mathematics》2008,6(4):610-621
In this paper, the concept of multi-valued weak contraction of Berinde and Berinde [8] for the Picard iteration in a complete
metric space is extended to the case of multi-valued weak contraction for the Jungck iteration in a complete b-metric space. While our main results generalize the recent results of Berinde and Berinde [8], they also extend, improve
and unify several classical results pertainning to single and multi-valued contractive mappings in the fixed point theory.
Our results also improve the recent results of Daffer and Kaneko [16].
相似文献
10.
Memudu O. Olatinwo 《Central European Journal of Mathematics》2008,6(2):335-341
In this paper, we establish some common fixed point theorems for selfmappings of a uniform space by employing both the concepts
of an A—distance and an E—distance introduced by Aamri and El Moutawakil [1] and two contractive conditions of integral type.
Our results are generalizations and extensions of the classical Banach’s fixed point theorem of [2, 3, 19], some results of
Aamri and El Moutawakil [1], Theorem 2.1 of Branciari [5] as well as a result of Jungck [7].
相似文献