Magnetically Tunable Kondo - Aharonov-Bohm Effect in a Triangular Quantum Dot

The role of discrete orbital symmetry in mesoscopic physics is manifested in a system consisting of three identical quantum dots forming an equilateral triangle. Under a perpendicular magnetic field, this system demonstrates a unique combination of Kondo and Aharonov-Bohm features due to an interplay between continuous [spin-rotation SU(2)] and discrete (permutation C3v) symmetries, as well as U(1) gauge invariance. The conductance as a function of magnetic flux displays sharp enhancement or complete suppression depending on contact setups.Comment: 4 pages, 3 .eps figure

Landau Damping in a 2D Electron Gas with Imposed Quantum Grid

Dielectric properties of semiconductor substrate with imposed two dimensional (2D) periodic grid of quantum wires or nanotubes (quantum crossbars, QCB) are studied. It is shown that a capacitive contact between QCB and semiconductor substrate does not destroy the Luttinger liquid character of the long wave QCB excitations. However, the dielectric losses of a substrate surface are drastically modified due to diffraction processes on the QCB superlattice. QCB-substrate interaction results in additional Landau damping regions of the substrate plasmons. Their existence, form and the density of losses are strongly sensitive to the QCB lattice constant.Comment: 9 pages, 12 eps-figure

Review of man-made mineral formations accumulation and prospects of their developing in mining industrial regions in Ukraine

Purpose. Analysis of the man-made mineral formations of ore mining and smelting, fuel and energy complexes development accumulation, location and prospects amount in the Dnipropetrovsk region. Methods. Comprehensive approach, including analysis of state statistics, waste handling sites (WHSs), regional environmental report, environmental passport of the region, as well as data from other information sources is used in the work. Aerial photographs of man-made formations were obtained using the Google Earth 7.1.8 satellite program. Findings. The analysis of the main man-made mineral formations of ore mining and smelting, fuel and energy complexes accumulation in Ukraine (coal and mining industry waste heaps, tailing dumps, ash dumps, smelter slag dumps) was conducted, their amount and occupied areas were estimated. According to the densest location of man-made formations, they are divided into 4 regions: the Prydniprovsk region, the Kryvyi Rih region, the Nikopol region, the Pavlohrad region. According to information sources, the content of some valuable components in man-made formations has been established. Based on the world market prices of technogenic deposits components research, it was proposed to grade them according to the cost of valuable components. The promising directions have been proposed for the use of mineral resources in various economic sectors. It is noted that from the perspective of development of mineral and raw materials potential, the bulk formations are of interest because of their large reserves in the minimum area. But from the perspective of environmental protection and the interests of the Ukrainian people, the bulk technogenic formations occupying significant areas of agricultural land and having smaller mineral reserves are of great interest. Originality. The conception of man-made raw material mineral fund for further industrial development as an alternative to natural deposits is extended and systematized. For the first time, an integrated and detailed analysis has been performed of technogenic waste of the largest waste storage region in Ukraine, as well as the grouping has been proposed of mining and energy sector waste by density of location and by the contained components value. Practical implications. A sketch-map of the man-made objects location was drawn up and their gradation was carried out according to the preliminary prospects of their development. This will provide a more objective approach to the concept of industrial waste development and planning the strategy for the development of mineral and raw materials potential both at the state and regional levels.утворень гірничо-металургійного й паливно-енергетичного комплексів Дніпропетровської області. Методика. У роботі використано комплексний підхід, що включає аналіз даних державної статистики, місць видалення відходів (МВВ), регіональної доповіді про стан навколишнього середовища, екологічного паспорта регіону, а також даних інших інформаційних джерел. Аерофотознімки техногенних утворень отримані за допомогою супутникової програми Google Earth 7.1.8. Результати. Проведено аналіз накопичення основних техногенних утворень гірничо-металургійного та паливно-енергетичного комплексів України (породні відвали вугільної й гірничорудної галузей, хвостосховища, золошлаковідвали, відвали металургійних шлаків), оцінені їх об’єми та займані площі. За найбільш щільним розташуванням техногенних утворень їх запропоновано розділити на 4 райони: Придніпровський, Криворізький, Нікопольський і Павлоградський. За даними інформаційних джерел встановлено вміст деяких цінних компонентів у різних техногенних відходах. На підставі вивчення світових ринкових цін компонентів техногенних родовищ запропоновано районувати їх за вартістю цінних компонентів у 1 т відходів. Запропоновано перспективні напрями використання мінерально-сировинних ресурсів у різних галузях економіки. Відзначено, що з позиції освоєння мінерально-сировинного потенціалу інтерес представляють насипні відходи в силу їх значних запасів на мінімальній площі, а з позиції охорони навколишнього середовища та інтересів українського народу – наливні техногенні відходи, що займають значні площі сільськогосподарських угідь і мають менші запаси мінеральної сировини. Наукова новизна. Розширено та систематизовано уявлення щодо мінерально-сировинного фонду техногенної сировини Дніпропетровської області для подальшого освоєння як альтернатива природним родовищам. Вперше здійснено комплексний та детальний аналіз техногенних відходів найбільшого регіону-накопичувача України і запропоновано групування відходів гірничодобувного та енергетичного сектору за щільністю розташування й вмістом цінних компонентів. Практична значимість. Складена схематична карта розташування техногенних відходів та проведена градація за попередньою перспективністю їх освоєння. Це дозволить більш об’єктивно підходити до концепції промислового освоєння техногенних відходів і планування стратегії розвитку мінерально-сировинного фонду на державному та регіональному рівнях.Цель. Анализ объемов накопления, мест расположения и перспектив промышленной разработки техногенных образований горно-металлургического и топливно-энергетического комплексов Днепропетровской области. Методика. В работе использован комплексный подход, включающий анализ данных государственной статистики, мест удаления отходов (МУО), регионального доклада о состоянии окружающей среды, экологического паспорта региона, а также данных других информационных источников. Аэрофотоснимки техногенных образований получены с помощью спутниковой программы Google Earth 7.1.8. Результаты. Проведен анализ накопления основный техногенных образований горно-металлургического и топливно-энергетического комплексов Украины (породные отвалы угольной и горнорудной отраслей, хвостохранилища, золошлакоотвалы, отвалы металлургических шлаков), оценены их объемы и занимаемые площади. По наиболее плотному расположению техногенных образований их предложено разделить на 4 района: Приднепровский, Криворожский, Никопольский и Павлоградский районы. По данным информационных источников установлено содержание некоторых ценных компонентов в разных техногенных отходах. На основании изучения мировых рыночных цен компонентов техногенных месторождений предложено районировать их по стоимости ценных компонентов в 1 т отходов. Предложены перспективные направления использования минерально-сырьевых ресурсов в различных отраслях экономики. Отмечено, что с позиции освоения минеральное-сырьевого потенциала интерес представляют насыпные отход по причине их больших запасов на минимальной площади, а с позиции охраны окружающей среды и интересов украинского народа – наливные техногенные образования, занимающие значительные площади сельскохозяйственных угодий и имеющие меньшие запасы минерального сырья. Научная новизна. Расширено и систематизировано представление о минерально-сырьевом фонде техногенного сырья Днепропетровской области для дальнейшего промышленного освоения как альтернатива природным месторождениям. Впервые осуществлен комплексный и детальный анализ техногенных отходов наиболее крупного региона-накопителя Украины и предложено группирование отходов горнодобывающего и энергетического сектора по плотности расположения и ценности содержащихся компонентов. Практическая значимость. Составлена схематическая карта размещения техногенных отходов и проведена градация по предварительной перспективности их освоения. Это позволит более объективно подходить к концепции промышленного освоения техногенных отходов и планирования стратегии развития минерально-сырьевого фонда на государственном и региональном уровнях.This work has been performed in the framework of tasks of a research project funded by the state budget by the Ministry of Education and Science of Ukraine (GP-500), and is also consistent with the “Dnipropetrovsk Regional Complex Program (Strategy) on Environmental Safety and Prevention of Climate Change for 2016 – 2025”

Anisotropy of graphite optical conductivity

The graphite conductivity is evaluated for frequencies between 0.1 eV, the energy of the order of the electron-hole overlap, and 1.5 eV, the electron nearest hopping energy. The in-plane conductivity per single atomic sheet is close to the universal graphene conductivity $e^2/4\hbar$ and, however, contains a singularity conditioned by peculiarities of the electron dispersion. The conductivity is less in the $c-$direction by the factor of the order of 0.01 governed by electron hopping in this direction.Comment: 3 pages, 3 figure

Universal Dynamic Conductivity and Quantized Visible Opacity of Suspended Graphene

We show that the optical transparency of suspended graphene is defined by the fine structure constant, alpha, the parameter that describes coupling between light and relativistic electrons and is traditionally associated with quantum electrodynamics rather than condensed matter physics. Despite being only one atom thick, graphene is found to absorb a significant (pi times alpha=2.3%) fraction of incident white light, which is a consequence of graphene's unique electronic structure. This value translates into universal dynamic conductivity G =e^2/4h_bar within a few percent accuracy

Kondo effect in systems with dynamical symmetries

This paper is devoted to a systematic exposure of the Kondo physics in quantum dots for which the low energy spin excitations consist of a few different spin multiplets $|S_{i}M_{i}>$. Under certain conditions (to be explained below) some of the lowest energy levels $E_{S_{i}}$ are nearly degenerate. The dot in its ground state cannot then be regarded as a simple quantum top in the sense that beside its spin operator other dot (vector) operators ${\bf R}_{n}$ are needed (in order to fully determine its quantum states), which have non-zero matrix elements between states of different spin multiplets $\ne 0$. These "Runge-Lenz" operators do not appear in the isolated dot-Hamiltonian (so in some sense they are "hidden"). Yet, they are exposed when tunneling between dot and leads is switched on. The effective spin Hamiltonian which couples the metallic electron spin ${\bf s}$ with the operators of the dot then contains new exchange terms, $J_{n} {\bf s} \cdot {\bf R}_{n}$ beside the ubiquitous ones $J_{i} {\bf s}\cdot {\bf S}_{i}$. The operators ${\bf S}_{i}$ and ${\bf R}_{n}$ generate a dynamical group (usually SO(n)). Remarkably, the value of $n$ can be controlled by gate voltages, indicating that abstract concepts such as dynamical symmetry groups are experimentally realizable. Moreover, when an external magnetic field is applied then, under favorable circumstances, the exchange interaction involves solely the Runge-Lenz operators ${\bf R}_{n}$ and the corresponding dynamical symmetry group is SU(n). For example, the celebrated group SU(3) is realized in triple quantum dot with four electrons.Comment: 24 two-column page

Changes in peripheral blood indicators and hemostatic system in patients with uterine fibroids

The article presents the results of studying the parameters of peripheral blood and the system of coagulation of patients with uterine fibroids. The analyzed data indicate the presence of a pronounced chronic inflammatory process, which is confirmed by the relevant indicators. The obtained results correlate with the data obtained by other authors. Since in the course of preliminary studies, the expediency of using the buccal epithelium to confirm the diagnosis of "uterine fibroids" has been determined, the blood system parameters have been confirmed once again confirm the high-visibility of this technique

The Missing Link: Magnetism and Superconductivity

The effect of magnetic moments on superconductivity has long been a controversial subject in condensed matter physics. While Matthias and collaborators experimentally demonstrated the destruction of superconductivity in La by the addition of magnetic moments (Gd), it has since been suggested that magnetic fluctuations are in fact responsible for the development of superconducting order in other systems. Currently this debate is focused on several families of unconventional superconductors including high-Tc cuprates, borocarbides as well as heavy fermion systems where magnetism and superconductivity are known to coexist. Here we report a novel aspect of competition and coexistence of these two competing orders in an interesting class of heavy fermion compounds, namely the 1-1-5 series: CeTIn5 where T=Co, Ir, or Rh. Our optical experiments indicate the existence of regions in momentum space where local moments remain unscreened. The extent of these regions in momentum space appears to control both the normal and superconducting state properties in the 1-1-5 family of heavy fermion (HF) superconductors.Comment: 6 pages, 2 figure

Dynamics of incidence of mental and behavior disorders in children of Ukraine: a 25-years’ observation experience.

Disorders of the psyche and behavior among children is an urgent problem of modern pediatric science and medical practice. The high prevalence of this pathology may be a result of the unfavorable psychological state of society, aggressive effects of the unfiltered information and negative influence of the environment (including radiatioactive factors) on the mind and body of the child. We have studied a 25-years’ trends in morbidity of mental illneses and behavior disorders among children of Ukraine in order to determine the impact of environmental factors (in particular - radioactivity after Chernobyl disaster in 1986) on their development. We have performed an analysis of the incidence and prevalence of psychiatric and behavioral disorders (PBD) among  children from different regions of Ukraine, including radioactive regions, contaminated after Chernobyl disaster. We used methods of statistical evaluation and epidemiological analysis of statistical data about the mental health of children of the country, aquired from the Ministry of Health of Ukraine. Over the past 25 years, we have observed trend of  reducing the incidence of PBD among children of Ukraine to 3.77 cases per 1,000 children (p<0.01) with prevalence of this pathology among children from large industrial and agricultural regions of the country. We have connected this trend with significant toxic influence of environmental factors on the child's organism. The incidence of PBD in the last 25 years among children from the regions of the country contaminated by the Chernobyl accident in 1986  (especially in Chernihiv and Zhytomyr regions) has exceeded the national incidence rates of PBD and its incidence among children from regions without territories of radiological control. In early 1990s the incidence of mental and behavioral disorders was high among children affected by Chornobyl accident. But over the last 25 years the incidence of PBD has become lower and now its level is even lower than among children who permanently lived in areas contaminated by radiation after the Chernobyl accident and the national incidence rate of PBD among children. The results of our 25-years’ follow-up of PBD morbidity among Ukrainian children have shown that children with prolonged exposure to ecotoxic factors, including radiation, have higher levels of prevalence and incidence of mental and behavioral disorders compared with other children. All this testify that there is a need of a proper correction programs and special attention to this cohort of children