Photonic Band Gaps of Three-Dimensional Face-Centered Cubic Lattices

We show that the photonic analogue of the Korringa-Kohn-Rostocker method is a viable alternative to the plane-wave method to analyze the spectrum of electromagnetic waves in a three-dimensional periodic dielectric lattice. Firstly, in the case of an fcc lattice of homogeneous dielectric spheres, we reproduce the main features of the spectrum obtained by the plane wave method, namely that for a sufficiently high dielectric contrast a full gap opens in the spectrum between the eights and ninth bands if the dielectric constant $\epsilon_s$ of spheres is lower than the dielectric constant $\epsilon_b$ of the background medium. If $\epsilon_s> \epsilon_b$, no gap is found in the spectrum. The maximal value of the relative band-gap width approaches 14% in the close-packed case and decreases monotonically as the filling fraction decreases. The lowest dielectric contrast $\epsilon_b/\epsilon_s$ for which a full gap opens in the spectrum is determined to be 8.13. Eventually, in the case of an fcc lattice of coated spheres, we demonstrate that a suitable coating can enhance gap widths by as much as 50%.Comment: 19 pages, 6 figs., plain latex - a section on coated spheres, two figures, and a few references adde

Photonic crystals of coated metallic spheres

It is shown that simple face-centered-cubic (fcc) structures of both metallic and coated metallic spheres are ideal candidates to achieve a tunable complete photonic bandgap (CPBG) for optical wavelengths using currently available experimental techniques. For coated microspheres with the coating width to plasma wavelength ratio $l_c/\lambda_p \leq 10$ and the coating and host refractive indices $n_c$ and $n_h$, respectively, between 1 and 1.47, one can always find a sphere radius $r_s$ such that the relative gap width $g_w$ (gap width to the midgap frequency ratio) is larger than 5% and, in some cases, $g_w$ can exceed 9%. Using different coatings and supporting liquids, the width and midgap frequency of a CPBG can be tuned considerably.Comment: 14 pages, plain latex, 3 ps figures, to appear in Europhys. Lett. For more info on this subject see http://www.amolf.nl/research/photonic_materials_theory/moroz/moroz.htm

Slow and fast magneto-optical response of magnetite nanoparticles suspension

DC magnetic field applied to Fe3O4 nanoparticle suspension affects its light scattering. Time dependent variations in the light intensity transmitted through a suspension are observed after the magnetic field is switched-on. Two types of variations can be distinguished. Fast response takes less than millisecond while slow variations occur at the time interval from seconds to hundreds of minutes. Possible mechanisms of these variations are discussed

Persistent currents in multicomponent Tomonaga-Luttinger liquid: application to mesoscopic semiconductor ring with spin-orbit interaction

We study persistent currents in semiconductor ballistic rings with spin-orbit Rashba interaction. We use as a working model the multicomponent Tomonaga-Luttinger liquid which arises due to the nonparabolic dispersion relations of electrons in the rings with rather strong spin-orbit coupling. This approach predicts some new characteristic features of persistent currents, which may be observed in experimental studies of semiconductor ballistic rings.Comment: 13 pages, 8 figure

Comparison of the diagnostic efficiency of various noninvasive methods for diagnosing liver fibrosis in patients with chronic viral hepatitis C

Summary: the article presents the results of the examination of patients with chronic viral hepatitis C namely the study of the informativeness of instrumental (fibroelastography) and serological (the content of hyaluronic acid in serum) of markers of fibrosis by assessing their predictive value by ROC- analysis. The purpose of the study: to find out the possibility of non-invasive methods for diagnosing liver fibrosis in patients with chronic viral hepatitis C (CHC). Materials and methods 66 patients with CHC with the 1-st genotype of the virus were examined, which were at the dispensary observation and ambulatory treatment at DCC CCH №1 in Vinnitsa and in the clinical department of viral hepatitis at the Institute of Epidemiology and Infectious Diseases named after L.V. Gromashevsky NAMS of Ukraine. All patients received fibroelastography (FEG) with a METAVIR score. All patients with CHC and group of control determined the content of hyaluronic acid (GA) in blood serum (ELISA using the Hyaluronic Acid (Corgenix, Inc., USA)). Research results Sensitivity of determination of GA in blood serum of patients with CHC with degree of fibrosis of liver F0-F2 was 91.23%, and specificity - 90.46%. For the FEG method, respectively: 74.33% and 77.25%. In the group of patients with degree of fibrosis F3 sensitivity of the definition of GA in blood serum was 72.21%, and specificity - 74.71%. The corresponding qualitative characteristics for FEG were: 98.32% and 91.45% respectively. The sensitivity of the determination of the content of GA in serum of patients with CHC with the degree of liver fibrosis F4 was 88.23%, and the specificity was 92.12%. For these patients the sensitivity and specificity of determining the degree of fibrosis by the FEG method were 87.78% and 91.45% respectively. Conclusions High diagnostic efficiency of determination of the content of GA in serum was established for assessing the degree of liver fibrosis in patients with CSF (AUC = 0,720-0,917, p˂0,01). Relatively higher sensitivity and specificity of the diagnosis of liver fibrosis was observed in determining the content of GA in serum compared with the FEG method (AUC = 0.914 vs. AUC = 0.817 (p˂0.05)) in the group with a lack or initial signs of liver fibrosis (F0-F2)

Дослідження екологічної безпеки виробництва морозива та оцінка якості кінцевого продукта

Мороз, Н. С. Дослідження екологічної безпеки виробництва морозива та оцінка якості кінцевого продукта = Research of ice cream production ecological safety and assessment of the final product quality : магістерська робота ; спец. 183 “Технології захисту навколишнього середовища“ / Н. С. Мороз ; наук. кер. Г. Г. Трохименко. – Миколаїв : НУК, 2020. – 93 с.Дипломна робота магістра на тему «Дослідження екологічної безпеки виробництва морозива та оцінка якості кінцевого продукту».Робота представлена пояснювальною запискою на 99 аркушах та презентацією загальною кількістю слайдів – 22. Структура роботи представлена вступом, п’ятьма розділами, висновками та списком використаної літератури. У роботі використано 26 таблиць та 21 рисунок, список використаної літератури містить 38 джерел.У вступі обґрунтована актуальність, поставлена мета, об’єкт, предмет та завдання. У першому розділі магістерської роботи розглянуто класифікацію видів діяльності та продукції, проаналізовано та описано основні технологічні процеси, що проходять на виробництві, проведено аналіз характеристик для виготовлення морозива, описано основні вимоги до сировини та вихідної продукції.У другому розділі роботи проведено аналіз існуючого обладнання для виробництва морозива, приведено його класифікацію. У третьому розділі описано аспекти впровадження концепції системи аналізу небезпечних чинників та критичних точок контролю на підприємствах з виробництва морозива, розглянуто нормативне підґрунтя на яких базується управління безпечністю харчових продуктів, подано результати дослідження зразків морозива за загальними, хімічними та мікробіологічними показниками, розроблено план аналізу небезпечних чинників та критичних точок контролю виробництва морозива. У четвертому розділі дипломної роботи проведено аналіз еколого-економічних проблем виробництва морозива.П’ятий розділ присвячено аналізу шкідливих та небезпечних факторів виробничого середовища та розробці заходів забезпечення пожежної безпеки на підприємстві з виробництва морозива.Результати роботи мають важливе теоретичне та практичне значення і з успіхом можуть бути використані у різних регіонах України, де функціонують підприємства з виробництва морозива.Master's thesis is on the topic: Research of ice cream production ecological safety and assessment of the final product quality».The work is presented in an explanatory note on 98 sheets and a presentation of the total number of slides – 22. The structure of the work is represented by an introduction, five sections, conclusions and a list of references. The paper uses 26 tables and 21 figures, the list of references contains 38 sources. The introduction substantiates the relevance, purpose, object, subject and research objectives.The first section of the master's thesis considers the classification of activities and products, analyzes and describes the main technological processes taking place in production, analyzes the characteristics for the production of ice cream, describes the basic requirements for raw materials and raw materials.In the second section of the work the analysis of the existing equipment for production of ice cream is carried out, its classification is resulted.The third section describes aspects of the implementation of the concept of hazard analysis and critical control points at ice cream enterprises, considers the regulatory framework on which food safety management is based, presents the results of ice cream samples for general, chemical and microbiological indicators, developed a hazard analysis plan and critical control points for ice cream production. In the fourth section of the thesis the analysis of ecological and economic problems of ice cream production is carried out.The fifth section is devoted to the analysis of harmful and dangerous factors of the production environment and the development of fire safety measures at the ice cream factory.The results of the work have important theoretical and practical significance and can be successfully used in different regions of Ukraine, where ice cream enterprises operate.The master's thesis is performed in Ukrainian

Multiplicity Fluctuations in the Pion-Fireball Gas

The pion number fluctuations are considered in the system of pions and large mass fireballs decaying finally into pions. A formulation which gives an extension of the model of independent sources is suggested. The grand canonical and micro-canonical ensemble formulations of the pion-fireball gas are considered as particular examples.Comment: 13 pages, 4 figure

Elasticity and electrostatics of plectonemic DNA

We present a self-contained theory for the mechanical response of DNA in single molecule experiments. Our model is based on a 1D continuum description of the DNA molecule and accounts both for its elasticity and for DNA-DNA electrostatic interactions. We consider the classical loading geometry used in experiments where one end of the molecule is attached to a substrate and the other one is pulled by a tensile force and twisted by a given number of turns. We focus on configurations relevant to the limit of a large number of turns, which are made up of two phases, one with linear DNA and the other one with superhelical DNA. The model takes into account thermal fluctuations in the linear phase and electrostatic interactions in the superhelical phase. The values of the torsional stress, of the supercoiling radius and angle, and key features of the experimental extension-rotation curves, namely the slope of the linear region and thermal buckling threshold, are predicted. They are found in good agreement with experimental data.Comment: 19 pages and 6 figure

The Single-Particle density of States, Bound States, Phase-Shift Flip, and a Resonance in the Presence of an Aharonov-Bohm Potential

Both the nonrelativistic scattering and the spectrum in the presence of the Aharonov-Bohm potential are analyzed. The single-particle density of states (DOS) for different self-adjoint extensions is calculated. The DOS provides a link between different physical quantities and is a natural starting point for their calculation. The consequences of an asymmetry of the S matrix for the generic self-adjoint extension are examined. I. Introduction II. Impenetrable flux tube and the density of states III. Penetrable flux tube and self-adjoint extensions IV. The S matrix and scattering cross sections V. The Krein-Friedel formula and the resonance VI. Regularization VII. The R --> 0 limit and the interpretation of self-adjoint extensions VIII. Energy calculations IX. The Hall effect in the dilute vortex limit X. Persistent current of free electrons in the plane pierced by a flux tube XI. The 2nd virial coefficient of nonrelativistic interacting anyons XII. Discussion of the results and open questionsComment: 68 pages, plain latex, 7 figures, 3 references and one figure added plus a few minor text correction

Tops and Writhing DNA

The torsional elasticity of semiflexible polymers like DNA is of biological significance. A mathematical treatment of this problem was begun by Fuller using the relation between link, twist and writhe, but progress has been hindered by the non-local nature of the writhe. This stands in the way of an analytic statistical mechanical treatment, which takes into account thermal fluctuations, in computing the partition function. In this paper we use the well known analogy with the dynamics of tops to show that when subjected to stretch and twist, the polymer configurations which dominate the partition function admit a local writhe formulation in the spirit of Fuller and thus provide an underlying justification for the use of Fuller's "local writhe expression" which leads to considerable mathematical simplification in solving theoretical models of DNA and elucidating their predictions. Our result facilitates comparison of the theoretical models with single molecule micromanipulation experiments and computer simulations.Comment: 17 pages two figure