Light absorption coefficient of an ordered array of spherical quantum dot chains

We considered intersubband electron transitions in an array of one-dimensional chains of spherical quantum dots in the GaAs/Al$_{x}$Ga$_{1-x}$As semiconductor system. The absorption coefficient caused by these transitions was calculated depending on frequency and polarization of incident light and on Fermi level position, and temperature. We established the existence of two maxima of the absorption coefficient at the edges of the absorption band. It is shown that the absorption coefficient reaches its maximal value at the center of the region between the $s$-, $p$-like subbands and slightly varies with temperature. The change of the direction of the linearly polarized light wave incident on the chains from perpendicular to parallel leads to a sharp narrowing of the absorption band. It is obtained that the absorption bandwidth increases with the reduction of the quantum dot radius. We also analyzed the dependence of the absorption coefficient of GaAs/Al$_{x}$Ga$_{1-x}$As superlattice on concentration of aluminium in the matrix.Comment: 9 pages, 7 figure

Interlevel absorption of electromagnetic waves by nanocrystal with divalent impurity

The energy spectrum of central divalent impurity is calculated using the effective mass approximation in a spherical quantum dot (QD). The dipole moment and oscillator strength of interlevel transition is defined. The dependence of linear absorption coefficient on the QD size and electromagnetic frequency is analyzed. The obtained results are compared with the results of univalent impurity.Comment: 8 pages, 8 figure

Effect of quantum dot shape of the GaAs/AlAs heterostructure on interlevel hole light absorption

The effect of quantum dot shape on the hole energy spectrum and optical properties caused by the interlevel charge transition based on the 4x4 Hamiltonian has been studied for the GaAs quantum dot in the AlAs semiconductor matrix. Calculations have been carried out in perturbation theory taking into account the hybridization of states for cubic, ellipsoidal, cylindrical and tetrahedral shapes by changing the volume of a quantum dot. Based on the energy calculations and on the determined wave functions of the hole states we have defined the selection rules and the dependence of the interlevel hole absorption coefficient on QD shapes and volumes.Comment: 10 pages, 6 figure

Off-central acceptor impurity in a spherical quantum dot

The hole energy spectrum with the ion of an acceptor impurity in the quantum dot has been calculated using the spherical approximation of the multiband Luttinger model. The dependence of the hole energy levels on the impurity location in the quantum dot has been studied. The effect of the impurity location on the dipole momentum and the oscillator strength has been analyzed. The hole interlevel absorption coefficient has been calculated.Comment: 10 pages, 5 figure

Analysis of the effect of polarization traps and shallow impurities on the interlevel light absorption of quantum dots

A spherical quantum dot (QD) heterosystem CdS/SiO$_2$ has been studied. Each QD has a hydrogen-like impurity in its center. Besides that, it has been accounted that a polarization trap for electron exists at the interfaces due to the difference between the QD and matrix dielectric permittivity. It has been defined that for small QD radii there are surface electron states. For different radii, partial contributions of the surface states into the electron energy caused by the electron-ion and electron-polarization charges interaction have been defined. The linear light absorption coefficient of noninteracting QDs has been calculated taking into account the QD dispersion by the size. It is shown that the surface states can be observed into different ranges of an electromagnetic spectrum.Comment: 8 pages, 4 figures, 1 tabl

The Presence of Selected Russian Fictional Characters in English Detective Fiction: A Brief Overview

The article deals with the stereotypical portrayal of certain Russian fictional characters in English literature from the mid-nineteenth century up to post-1991 fictio

Lexical interaction of the modern Greek language with Germanic and Romance languages (with reference to the vocabulary of English, French and modern Greek languages)

The article deals with the issues of lexical interaction of the modern Greek language with Germanic and Romance languages (represented by English and French). There were singled out two areas in which this lexical interaction is rather significant: the vocabulary related to food and drinks and the vocabulary used to designate objects and concepts of clothing, shoes, haberdashery and perfumer

ЗАСТОСУВАННЯ ІНТЕРАКТИВНИХ МЕТОДІВ НАВЧАННЯ ПРИ ВИВЧЕННІ ДИСЦИПЛІНИ «МЕДСЕСТРИНСТВО В СІМЕЙНІЙ МЕДИЦИНІ»

The efficiency of the use of interactive teaching methods based on the study of dynamic indicators of 4-year student on specialty “Nursing” as a result of practically-oriented exam and medical licensing examination “Krok M. Nursing”. It is shown that the introduction of the latest model of the educational process of discipline “Nursing in Family Medicine” allowed twofold increase students’ knowledge in preparation for the practically-oriented state exam and license examination “ Krok M. Nursing”.Оцінено ефективність застосування інтерактивних методів навчання на підставі вивчення динамічних показників успішності студентів 4 курсу спеціальності «Сестринська справа» за результатами практично-орієнтованого іспиту та медичного ліцензійного іспиту «Крок М. Сестринська справа». Показано, що впровадження даної новітньої моделі організації навчального процесу з дисципліни «Медсестринство в сімейній медицині» дозволило вдвічі підвищити рівень знань студентів при підготовці до практично-орієнтованого державного іспиту та ліцензійного іспиту «Крок М. Сестринська справа»

НОВІ ПІДХОДИ ДО ЛІКУВАННЯ СКЛЕРОПОЛІКІСТОЗНИХ ЯЄЧНИКІВ У КЛОСТИЛБЕГІТ-РЕЗИСТЕНТНИХ ЖІНОК

At ЗО women with polycystosys ovaries ovulation was inducted by clostylbegit. Having analyzed the anamnesis, clinical and laboratory data, and the results of the induction of ovulation, we concluded, that90,1% of women are resistant to such a therapy. We need to find additional methods for inducting the ovulation in such group of patients.Проводилось исследование эфективности применения клостилбегита для индукции овуляции у женщин со склерополикистозными яичниками. В результате анализа анамнестических, клинико-лабораторных данных и оценки проведённого курса лечения ЗО женщин, пришли к выводу о резистентности женщин к этому препарату (у 90,1% случаев).Для улучшения результатов индукции овуляции необходим поиск дополнительных препаратов, которые влияют на патогенез данного заболевания.Досліджувалося використання клостилбегіту для індукціїовуляціїу жінок із склерополікістозними яєчниками. Після аналізу анамнестичних, клініко-лабораторних даних і оцінки проведеного курсу лікування ЗО жінок, зроблено висновок про резистентність жінок до даного препарату (у 90,1% випадків) і необхідність пошуку додаткових, патогенетично обґрунтованих засобів, для покращення результатів індукціїовуляції