6,204 research outputs found

    Boundary value problems of elasticity theory for plane domains with one-dimensional elastic reinforcements

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    This article is a translation of an article published in Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No 1, pp 103-114 Jan-Feb 1991.Many authors have examined problems related to the load transmission from an elastic rod to an elastic plane. It was assumed in the majority of investigationa that the stringer is a thin rectilinear rod transmitting only longitudinal forces while the rod contact with the plane is realized along a line. different modifications of sheet contact with a rectilinear tensile stringer considered as an inner stringer of finite length or as an infinite edge stringer were analyzed in [1, 2]. Problems about the reinforcement of holes in a plate by a thin rod of constant section that possesses bending and longitudinal stiffnesses were solved in [3]. The eccentricity of the connection between the shell middle surface and the rod was taken into account in [4] in a study of shells reinforced by thin curvilinear rods. Other models of the one-dimensional element connected to an elastic medium without taking account of its bending stiffness were analyzed in [5, 6]. Solutions of a number of problems with circular reinforcing elements are obtained in [7]. An isotropic finite or infinite, linearly elastic plate reinforced along part or all of the boundary and along certain internal lines by elastic curvilinear rods possessing variable longitudinal and bending stiffnesses, variable curvature and thickness, the eccentricity of the connection to the plate and with an arbitrary transverse section shape symmetric relative to the plate middle surface are studied in this paper. Boundary conditions on the line of plate contact with the inner or edge elastic rods are obtained for the reinforcement models generalizing [1, 2] by using the theory of elastic rods in the case of a plane state of stress. Existence and uniqueness theorems are proved for appropriate boundary value problems; the singularity of the stresses at angles and tips of the rods are proved. The relationships obtained carry over completely to the plane strain problem for an elastic cylinder reinforced by homogeneous cylindrical shells along the generator. Some of the results described here are represented in [8]

    Innovations in management of labour adaptation of police officers to market economy

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    The author offers the concept of the psychological mechanism of adaptation. In his opinion process of change of mental sets, motives is the cornerstone of the psychological mechanism of adaptation, is more whole than an adaptant. An experimental basis of the concept of the psychological mechanism of adaptation is questioning of 160 police officers of Sverdlovsk region. A sample — quote.Автор предлагает концепцию психологического механизма адаптации. В основе психологического механизма адаптации, по его мнению, лежит процесс смены психологических установок, мотивов, целей адаптанта. Экспериментальной основой концепции психологического механизма адаптации является анкетирование 160 сотрудников МВД Свердловской области. Выборочная совокупность — квотная

    Molecular gyroscopes and biological effects of weak ELF magnetic fields

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    Extremely-low-frequency magnetic fields are known to affect biological systems. In many cases, biological effects display `windows' in biologically effective parameters of the magnetic fields: most dramatic is the fact that relatively intense magnetic fields sometimes do not cause appreciable effect, while smaller fields of the order of 10--100 μ\muT do. Linear resonant physical processes do not explain frequency windows in this case. Amplitude window phenomena suggest a nonlinear physical mechanism. Such a nonlinear mechanism has been proposed recently to explain those `windows'. It considers quantum-interference effects on protein-bound substrate ions. Magnetic fields cause an interference of ion quantum states and change the probability of ion-protein dissociation. This ion-interference mechanism predicts specific magnetic-field frequency and amplitude windows within which biological effects occur. It agrees with a lot of experiments. However, according to the mechanism, the lifetime Γ1\Gamma^{-1} of ion quantum states within a protein cavity should be of unrealistic value, more than 0.01 s for frequency band 10--100 Hz. In this paper, a biophysical mechanism has been proposed that (i) retains the attractive features of the ion interference mechanism and (ii) uses the principles of gyroscopic motion and removes the necessity to postulate large lifetimes. The mechanism considers dynamics of the density matrix of the molecular groups, which are attached to the walls of protein cavities by two covalent bonds, i.e., molecular gyroscopes. Numerical computations have shown almost free rotations of the molecular gyros. The relaxation time due to van der Waals forces was about 0.01 s for the cavity size of 28 angstr\"{o}ms.Comment: 10 pages, 7 figure

    Distribution of reflection eigenvalues in many-channel chaotic cavities with absorption

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    The reflection matrix R=S^{\dagger}S, with S being the scattering matrix, differs from the unit one, when absorption is finite. Using the random matrix approach, we calculate analytically the distribution function of its eigenvalues in the limit of a large number of propagating modes in the leads attached to a chaotic cavity. The obtained result is independent on the presence of time-reversal symmetry in the system, being valid at finite absorption and arbitrary openness of the system. The particular cases of perfectly and weakly open cavities are considered in detail. An application of our results to the problem of thermal emission from random media is briefly discussed.Comment: 4 pages, 2 figures; (Ref.[5b] added, appropriate modification in text

    Vector Meson Production in Ultraperipheral Heavy Ion Collisions

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    The ultraperipheral heavy ion collisions (UPC's) are an important alternative to study the QCD dynamics until the next generation of e+e/ep/eAe^+e^-/ ep / eA colliders become reality. Due to the coherent action of all the protons in the nucleus, the electromagnetic field is very strong and the resulting flux of equivalent photons is large, which allows to study two-photon as well as photonuclear interactions at high energies. In this paper we present a brief review of the vector meson production in UPC's at high energies using the QCD color dipole approach to describe their photonuclear production and the perturbative QCD Pomeron (BFKL dynamics) to describe the double meson production in photon-photon process. Predictions for rates and integrated cross sections are presented for energies of RHIC and LHC.Comment: 16 pages, 1 figure. Version to be published in Journal of Physics G: Nuclear and Particle Physic

    System analisis of the adaptation of the agricultural people

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    Автор предлагает концепцию психологического механизма адаптации. В основе психологического механизма адаптации по его мнению лежит процесс смены психологических установок, мотивов, целей адаптанта. Экспериментальной основой концепции психологического механизма адаптации является анкетирование 160 человек жителей свердловской области. Выборочная совокупность — квотная.Author suggest (propose) conception psycological mechanism adaptation. The basis of the concept psycological mechanism adaptation occur (strike) the process of the changing psycological attitudes, motives, purposes of the adaptater. Experimental basis of the conception psycological mechanism adaptation consist in the psycological investigation of the mechanism adaptation was testing 160 people, which was living in the sverdlovsk and cheljabinsk region. The elective totality — cvota

    Влияние дородового излития околоплодных вод на исходы многоплодной беременности

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    Department of Obstetrics and Gynecology, Scientific Research Institute of Mother and Child Health Care, Congresul III al Medicilor de Familie din Republica Moldova, 17–18 mai, 2012, Chişinău, Republica Moldova, Conferinţa Naţională „Maladii bronhoobstructive la copii”, consacrată profesorului universitar, doctor habilitat Victor Gheţeul, 27 aprilie, Chişinău, Republica MoldovaThe relevance of twin pregnancy is determined by the high perinatal morbidity and mortality, a great deal of complications during childbirth and high rate of caesarean sections. Spontaneous preterm birth is the leading cause of perinatal morbidity and mortality in twin pregnancies, with preterm premature rupture of membranes a significant cause. The article presents the results of a retrospective study based on the analysis of 160 obstetric records from all twin pregnancies delivered in 2010 in the Scientific Research Institute of Mother and Child Health Care. The aim of the present study was to define the incidence of PROM in twin pregnancies at < 34 weeks of gestation, to highlight the risk factors involved, which predispose to the development of PROM, as well as to evaluate maternal and fetal complications that occur secondary to premature rupture of membranes.Актуальность изучения многоплодной беременности связана с повышенной перинатальной заболеваемостью и смертностью, большим количеством осложнений родов, а также высокой частотой кесарева сечения. Преждевременные роды, часто дебютируя с дородового излития околоплодных вод, представляют собой основную причину перинатальной заболеваемости и смертности у близнецов. В статье представлены результаты ретроспективного исследования, основанного на анализе 160 акушерских историй женщин, родоразрешенных в Научно-Исследовательском Институте Охраны Здоровья Матери и Ребенка в течение 2010 года. Целью настоящего исследования явилась оценка частоты ПИОВ при многоплодной беременности с гестационным сроком < 34 недели, выявление факторов риска, ведущих к ПИОВ, а также оценка осложнений со стороны матери и плода, появляющихся вследствие разрыва плодных оболочек до начала родовой деятельности
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