Charge carrier injection into insulating media: single-particle versus mean-field approach

Self-consistent, mean-field description of charge injection into a dielectric medium is modified to account for discreteness of charge carriers. The improved scheme includes both the Schottky barrier lowering due to the individual image charge and the barrier change due to the field penetration into the injecting electrode that ensures validity of the model at both high and low injection rates including the barrier dominated and the space-charge dominated regimes. Comparison of the theory with experiment on an unipolar ITO/PPV/Au-device is presented.Comment: 32 pages, 9 figures; revised version accepted to PR

Map scheme of the housing fund of the Zhytomyr region: qualitative and quantitative analysis

The housing fund, as a concept, is a complex of interrelated indicators characterizing its condition. First of all, it is the availability of housing, that is, the amount of living space per person of the population. This also includes the total living area, the number of houses and apartments, and the equipment of the housing stock by types of terrain. It is known that Ukraine has almost the lowest rate of housing security among European countries. It is about 29 m2/person. While other countries have much higher housing affordability, ranging from 31,2m2/person (Estonia) to 66,3m2/person (Luxembourg). The reasons for this state of affairs in our country are the inefficient use of land within categories, the inaccessibility of housing for many segments of the population, the lack of state programs for financing construction and lending housing, low wages, etc. The goal of our research was to study the housing stock of the Zhytomyr region with further analysis of its condition. Based on the results of the research, maps of the provision of housing for the urban and rural population in the sections of Zhytomyr regiont were constructed. The largest amount of living space per person was observed in Brusylivskiy, Ruzhynskiy, Popilnyanskiy and Narodytskiy districts (30–40 m2). Moreover, security in rural areas is somewhat higher than in urban areas. In our opinion, the reason for this is the lower population concentration in small settlements. Therefore, population size as a factor influencing the condition of the housing stock of Zhytomyr region is one of the main, but not the only factors. It was also established that over the past 15 years, the average housing supply in the region increased from 23,3 m2 to 28,3 m2 per person, while the number of apartments and houses actually remained at the same level (968,1 thousand in 2005 and 974,4 thousand in 2020), and the population has decreased significantly. Therefore, the reason for the increase in the housing supply indicator is not the improvement of the quantitative and qualitative condition of the housing stock of the Zhytomyr region, but rather the decrease in the number of residents. Along with the quantitative analysis, a qualitative analysis of the housing stock was also conducted. It has been established that housing equipment with plumbing, sewage, and hot water has increased by almost 50% over the past fifteen years, especially in rural areas. And in general, the qualitative characteristics of the housing stock in the Zhytomyr region are somewhat inferior to similar ones in Ukraine

Синтез карналлита из растворов хлорида магния и калия

The influence of the main parameters on the process of obtaining artificial carnallite and its quality has been established. It is shown that to obtain a product with a high content of the carnallite phase and a low content of bischofite and KCl, it is necessary to use magnesium chloride solution with the concentration of 27-30 % and preheated ground potassium chloride. The process should be carried out at the temperature of 80 °C. The formation of synthetic carnallite, close in composition to the enriched one, occurs when the ratio of potassium chloride to magnesium chloride in the initial mixture is equal or close to their stoichiometric ratio in carnallite. With an excess of potassium chloride in the reaction mixture, an increased content of potassium and sodium chlorides in the product is observed, and with its deficiency, the product contains an increased amount of bischofite phase. To reduce the hydrolysis of magnesium chloride during dehydration, a slight excess of potassium chloride should be maintained in the mixture entering the synthesis. It is shown that the most advantageous scheme for producing artificial carnallite provides for incomplete evaporation of desulfurized liquor in the presence of potassium chloride with the return of circulating carnallite liquor to the desulfurization stage.Установлено влияние основных параметров на процесс получения искусственного карналлита и качество продукта. Показано, что для получения продукта с высоким содержанием карналлитовой фазы и небольшим содержанием бишофита и КС1 необходимо использовать раствор хлорида магния с концентрацией 27-30 %, предварительно нагретый, измельченный хлорид калия, процесс проводить при температуре 80 °С. Образование синтетического карналлита, близкого по составу к обогащенному, происходит при соотношении хлорида калия к хлориду магния в исходной смеси равном или близком к их стехиометрическому соотношению в карналлите. При избытке хлорида калия в реакционной смеси наблюдается повышенное содержание хлоридов калия и натрия в продукте, а при его недостатке продукт содержит повышенное количество бишофитовой фазы. Для снижения гидролиза хлорида магния при обезвоживании в поступающей на синтез смеси следует поддерживать небольшой избыток хлорида калия. Показано, что наиболее выгодная схема получения искусственного карналлита предусматривает неполную выпарку обессульфаченного щелока в присутствии хлорида калия с возвращением оборотного карналлитового щелока на стадию обессульфачивания

НОВА СИМЕТРІЯ ЕЛЕКТРОСЛАБКОГО ЛАГРАНЖІАНУ

Аналізуються проблеми стандартної моделі, пов'язані з введенням електромагнітного поля як лінійної комбінації полів, на яких реалізуються представлення різних калібрувальних груп. В роботі звертається увага на те що в будь-якій моделі із калібрувальними полями, генератори, які входять до коваріантних похідних, можуть бути задані лише з точністю до переходу до еквівалентного представлення. Пропонується вважати що динамічні моделі з еквівалентними представленнями генераторів повинні бути фізично еквівалентними. Це означає вимогу симетрії лагранжіану відносно переходу від одного з еквівалентних представлень генераторів до іншого. Зокрема в лагранжіані стандартної моделі маємо підвищуючий і понижуючий генератори групи SU(2). Закон групового множення визначає лише модулі  матричних елементів цих генераторів, в той час як аргументи залишаються невизначеними. В роботі така невизначеність розглядається як локальна. В різних точках простору-часу генератори можуть задаватися в різних еквівалентних представленнях. Компенсація невизначених аргументів матричних елементів генераторів групи SU(2) може бути проведена за допомогою локального U(1) - перетворення з введенням відповідного калібрувального поля, яке може розглядатися як електромагнітне. Аналізуються переваги такого введення електромагнітного поля у порівнянні з методом, використаним в стандартній моделі

Self-consistent Coronal Heating and Solar Wind Acceleration from Anisotropic Magnetohydrodynamic Turbulence

We present a series of models for the plasma properties along open magnetic flux tubes rooted in solar coronal holes, streamers, and active regions. These models represent the first self-consistent solutions that combine: (1) chromospheric heating driven by an empirically guided acoustic wave spectrum, (2) coronal heating from Alfven waves that have been partially reflected, then damped by anisotropic turbulent cascade, and (3) solar wind acceleration from gradients of gas pressure, acoustic wave pressure, and Alfven wave pressure. The only input parameters are the photospheric lower boundary conditions for the waves and the radial dependence of the background magnetic field along the flux tube. For a single choice for the photospheric wave properties, our models produce a realistic range of slow and fast solar wind conditions by varying only the coronal magnetic field. Specifically, a 2D model of coronal holes and streamers at solar minimum reproduces the latitudinal bifurcation of slow and fast streams seen by Ulysses. The radial gradient of the Alfven speed affects where the waves are reflected and damped, and thus whether energy is deposited below or above the Parker critical point. As predicted by earlier studies, a larger coronal ``expansion factor'' gives rise to a slower and denser wind, higher temperature at the coronal base, less intense Alfven waves at 1 AU, and correlative trends for commonly measured ratios of ion charge states and FIP-sensitive abundances that are in general agreement with observations. These models offer supporting evidence for the idea that coronal heating and solar wind acceleration (in open magnetic flux tubes) can occur as a result of wave dissipation and turbulent cascade. (abridged abstract)Comment: 32 pages (emulateapj style), 18 figures, ApJ Supplement, in press (v. 171, August 2007