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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.


Klinke, James 05 December 2012 (has links)
Artist Statement I have often created art with an organic quality because I have felt bound by the earth’s natural elements and forces. These extend to and influence my human qualities which influence my artwork. My paintings and mixed media works symbolize the issues and defects that affect me in various ways and represent my attempt at overcoming them. At its core, my body of work addresses psychological and emotional recovery work. I have been burdened for a long period of time with anxiety, various character defects, and difficulties but I find catharsis through creative expression. Because I have chosen to address and convey my on-going struggle for emotional well-being in my work, I depict distorted images which I sometimes describe as ghostlike figures. These images symbolize the issues and defects that often have a negative impact on my life. However, in many ways, these images also symbolize to me the gratitude I feel for overcoming such trying times. For without these psychological and emotional trials and tribulations, I would not be the person I am at this point in my life. I now possess the tools I need to develop a healthier quality of life. My experiences are reflected in my works.

Predicting drag losses & oil flow characteristics in a wet clutch system using numerical analysis

Liljegren, Marcus, Ljeskovica, Edin January 2016 (has links)
This report presents the Master Thesis done by two students at the Mechanical Engineering program, Design Engineering at Luleå University of Technology. The thesis was performed at Luleå University of Technology in collaboration with BorgWarner PDS located in Landskrona. The objective for the thesis was to study the potential for predicting and optimizing drag losses and oil flow characteristics in a wet clutch system using numerical simulations in LS-DYNA. BorgWarner PDS manufactures and distributes the Haldex coupling, which is an electro-hydraulic coupling used in an active four-wheel drive system. BorgWarner PDS strives to make the Haldex coupling more efficient by minimizing energy losses in order to lower fuel consumption for the vehicle and a smaller impact on the environment. As testing on prototypes are costly and time consuming it is therefore desirable to use numerical simulations instead. To determine the potential for numerical simulations to predict and optimize both drag losses and oil flow characteristics a numerical model was set up using LS-DYNA. A test rig was designed in order to achieve a controlled testing environment in order to validate the numerical models, both qualitatively and quantitatively. The numerical model uses the built in Fluid Structure Interaction method in LS-DYNA, which is a combination of a structural model and an incompressible fluid model. The test rig measures torque on the clutch housing induced by the dragging of oil as the clutch drum rotates. The tests were performed using different rotational speeds, varying from 250-1500 rpm, and different clutch housing geometries. The results were gathered from an average of ten measurements of the drag torque. A high- speed camera was also used to capture the oil flow characteristics. The numerical simulations were done using the same parameters used for the tests i.e. different rotational speeds and clutch housing geometries. In addition, each simulation was performed using different mesh sizes; 0.5 mm, 1 mm and 2 mm in order to analyze mesh dependence. The numerical model was set to measure the drag torque on the clutch drum and was then compared to the experimental results in order to validate the numerical model quantitatively. The oil flow characteristics from the numerical simulation were compared to the high-speed movies to validate the numerical model qualitatively. The numerical model shows promising results when it comes to predicting drag torque and oil flow characteristics. The results also show that using a numerical model for optimization purposes are possible as the experimentally measured drag torque at different clutch house geometries corresponds to the numerically simulated drag torque. The conclusions from this Master Thesis is that numerical simulations do have a potential for predicting drag losses and oil flow characteristics in a wet clutch system. The numerical model created in this project can also be used to obtain valuable information about geometry changes when it comes to optimizing the wet clutch system. However, the numerical model is still at an early stage and can be seen as a second generation model where further work needs to be done in order to include more of the complex geometries of a wet clutch system have. Although LS-DYNA is state-of-the-art when it comes to these kinds of complex simulations it still needs to be developed further to handle such complex simulations.

Palmer amaranth control in established alfalfa and documentation of glyphosate-resistant Amaranthus species in Kansas

Putman, Joshua Adam January 1900 (has links)
Master of Science / Department of Agronomy / Dallas Peterson / Palmer amaranth is a troublesome weed that competes for water, nutrients, and sunlight in many cropping systems throughout the United States. It is a serious production problem for alfalfa growers in the southern Great Plains region because of extended germination and impact on forage quality and yields. Glyphosate has been used extensively to control Palmer amaranth but control has become difficult. The objectives of this research were to (1) evaluate various herbicide treatments for Palmer amaranth control in established alfalfa, (2) confirm the presence and scope of glyphosate-resistance in common waterhemp and Palmer amaranth populations in eastern Kansas, and (3) to characterize glyphosate-resistance in two Palmer amaranth populations from south central Kansas. Residual Palmer amaranth control in alfalfa varied among herbicide treatments. The best late season Palmer amaranth control was accomplished with sequential treatments that included flumioxazin at 140 g ha-1 or diuron at 2,690 g ha-1 as dormant applications followed by a between cutting treatment of flumioxazin at 70 g ha-1, which was still providing 85 to 96% control in late summer. Several other treatments provided good early season Palmer amaranth control, but control diminished as the season progressed. Palmer amaranth emerges throughout the growing season and therefore, sequential herbicide treatments with good residual activity may be necessary for season-long control. Greenhouse studies indicated that glyphosate-resistant common waterhemp is present throughout eastern Kansas with several populations that survived glyphosate up to two times the suggested use rate. Glyphosate-resistant Palmer amaranth was documented in several populations collected from various counties throughout Kansas. Two populations collected in south central Kansas in 2011 survived up to eight times the typical field use rate of glyphosate. Six more populations collected in 2012 displayed similar resistance characteristics with three populations surviving up to four times the typical rate of glyphosate. Shikimate assays on susceptible and resistant Palmer amaranth biotypes confirmed resistance to glyphosate.

Generation of Ultra-Packed Thermal Greases and Evaluation of their Effective Properties

Sukshitha Achar Puttur Lakshminarayana (5930798) 16 January 2019 (has links)
Thermal Greases are gap-filling interface materials that are used in semiconductor packages to efficiently transfer heat from the component to the heat sink or spreader. Thermal greases are typically particle filled composite materials comprising of highly conducting fillers in a poorly conducting, but mechanically soft, silicone or epoxy base matrix. Generally, the effective conductivity of the greases increases with increasing volume fractions of fillers. However, the fillers also have high elastic modulus that induces undesirable thermal stresses on the brittle silicon device. Therefore, as device power density increases, there is a need to increase particle volume loading, which in turn necessitates optimally balancing the material’s thermal and mechanical characteristics.<div><br></div><div>In this thesis, procedures are developed to simulate packed microstructures of particles so as to identify the optimal trade-off between thermal and mechanical behavior. Experimental and numerical simulations of microstructures that have been generated as reported in the literature were found to have volume fractions of around 60%. However, as commercially available thermal greases have volume fractions in the range of 60 − 80%, there is a need to develop an efficient algorithm to generate microstructures numerically. The particle packing is initially posed as a nonlinear programming problem and rigorous optimization search algorithms are systematically applied to generate particle systems that are compactly packed, but without particle overlap. Since the packing problem is computationally expensive, the algorithms are systematically evaluated to improve computational efficiency as measured by the number of particles in the system, as well as the time to generate the microstructure. The evaluated algorithms include the inefficient penalty function methods, best-in-class sequential programming method, matrix-less conjugate gradient method as well as the augmented Lagrangian method. In addition, heuristic algorithms are also evaluated to achieve computationally efficient packing. The evaluated heuristic algorithms are mainly based on the Drop-Fall-Shake method, but modified to more effectively simulate the mixing process in commercial planetary mixers. With the developed procedures, Representative Volume Elements (RVE) with volume fraction as high as 74% were achieved. <br></div><div><br></div><div>After the microstructurs were generated, the effective thermal conductivity and effective elastic modulus were estimated using a ‘Random Network Model (RNM)’ that was previously developed. The RNM solves the near-percolation heat conduction problem with hundreds of thousands of particles in minutes compared to hours or days that a full-field simulation requires. The approximations inherent in the RNM are valid if the particulate composite has widely different matrix and particle properties, which is true in the case of thermal greases. In the present thesis, the previously developed RNM was modified to account for the fact that the generated RVEs contain sides with cut particles.<br></div>

Краудинвест – как новый инструмент привлечения инвестирования на реализацию девелоперских проектов : магистерская диссертация / Credinvest as a new tool to attract investment for development projects

Бусыгин, А. С., Busygin, A. S. January 2017 (has links)
Structure of a thesis includes introduction, three chapters, conclusion, list of used sources and applications. In the introduction the choice of the research topic, its topicality, formulates the goal and objectives, identified the subject and object of research, its theoretical bases, scientific novelty are marked. In the first Chapter "Crowdiness" describes the main terms and concepts of the system, the history of its creation and formation, practical application in foreign countries and in Russia, as well as the advantages, disadvantages and risks of the system in its application. In the second Chapter, "Evaluation and analysis of the region to implement a development project" conducted socio-economic analysis of the region that was selected for the implementation of development projects. Discusses his prospects and opportunities in the near future, the analysis needs of commercial space (Shopping Center) for the population in this city. In the third Chapter "Calculation of economic efficiency of a development project, applying the scheme credinvest" made the analysis of the locations of the object in a certain area, its economic justification, and all financial calculations and timeline. Also provides all the technical characteristics of the object, its concept and appeal. The following is the calculation for the three funding schemes – 100% equity, 50% to 50% of own capital and Bank credit and scheme that is the subject of the thesis – kruzinshtern (50% SC 50% SIF). The Appendix contains all graphs and calculations of comparative analysis, which indicate the effectiveness of the scheme of credinvest. In conclusion the main conclusions of the work. Master thesis contains 74 pages of printed text, in the thesis presented 28 figures, 10 tables, 16 appendices, the list of references includes 62 names. / Структура магистерской диссертации включает в себя введения, три главы, заключение, списка использованных источников и приложения. Во введении обоснован выбор темы исследования, её актуальность, сформулированы цель и задачи работы, определены предмет и объект исследования, его теоретические основы, обозначена научная новизна. В первой главе «Краудфинансы» рассмотрены основные термины и понятия системы, история её создания и становления, практика применения в зарубежных странах и в России, а также плюсы, минусы и риски данной системы при ее применении. Во второй главе «Оценка и анализ региона для реализации девелоперского проекта» проводится социально-экономический анализ региона, который был выбран для реализации девелоперского проекта. Рассматриваются его перспективы и возможности в ближайшем будущем, проводится анализ потребности коммерческих площадей (Торгово-развлекательного Центра) для населения в данном городе. В третьей главе «Расчет экономической эффективности девелоперского проекта с учетом применения схемы краудинвеста» производятся анализ локации объекта в определенном районе, его экономическое обоснование и все финансовые расчеты и сроки реализации. Также приводятся все технические характеристики объекта, его концепция и привлекательность. Далее проводится расчет по трем схемам финансирования – 100% собственного капитала, 50% на 50% собственного капитала и банковского кредита и по схеме, которая и является темой диссертации – краудинвестировние (50% СК на 50% ПИФ). В приложениях приведены все графики и расчеты сравнительного анализа, которые указывают на эффективность схемы краудинвеста. В заключении сформулированы основные выводы работы. Магистерская диссертация содержит 74 страницы печатного текста, в диссертации представлены 28 рисунков, 10 таблиц и 16 приложений, список использованных источников включает 62 наименования.

Специфика юмора в литературном творчестве Вуди Аллена (на материале сборников рассказов и пьес) : магистерская диссертация / Specificity of humor in the literary work of Woody Allen (on the material of collections of short stories and plays)

Баисова, А. Ю., Baisova, A. Y. January 2017 (has links)
The work is devoted to the analysis of various manifestations of the comic (forms, ways, devices, etc.) in the literary works of Woody Allen, taking into account the specifics of the American-Jewish tradition of humor. The research is based on Allen's short story collections Getting Even, 1971, "Without Feathers" (1975), "Side Effects" (1980), and a collection of plays " Riverside Drive" (Three one-act plays, 2003). In chapter 1 of our study we gave a brief overview of the comic as a literary category, as it is exactly humor that distinguishes Allen’s literary style the most. Studying and analyzing stories, we also found that his humor is clearly culturally-marked, which is why in chapter 1 of our study a section appeared devoted to the peculiarities of American and Jewish humor. In Chapter 2, before proceeding directly to the analysis of collections, we attempted to briefly define the specific character of the story as a genre and outline the historical and literary context of its development in American culture. An analysis of the collections was conducted, during which we revealed that the leading comic effect in the stories is irony. We also found that the stories can be divided into 6 types, each corresponding to its own pragmatic effect. Headlines of stories can be divided into 3 types, each built on a comic combination of high and low, imbued with burlesque or travesty features. Chapter 3 of our thesis is devoted to the study of the dramatic works by W. Allen, which, in fact are quite few, only 6 plays –3 of them, included in the collection "Riverside Drive", being an immediate subject of analysis. A leading stylistic device here is the irony. The appendix contains an excerpt from an interview with Woody Allen, designed as a book “Woody Allen: An Interview with Stig Björkman.” / Работа посвящена анализу различных проявлений комического (формы, способы, средства и пр.) в литературном наследии Вуди Аллена с учетом специфики американо-еврейской юмористической традиции. В качестве материала исследования в диссертации используются сборники рассказов Аллена «Сводя счеты» (Getting Even, 1971), «Без перьев» (Without Feathers, 1975), «Побочный эффект» (Side Effect, 1980), а также сборник пьес «Риверсайд Драйв» (Three one-act plays, 2003). В 1 главе своего исследования мы дали краткий обзор комического как литературоведческой категории. Основной категорией, характеризующей творчество Аллена, по нашему мнению, является именно юмор. Изучая и анализируя рассказы, мы также обнаружили, что его юмор носит явно выраженный национальный характер, именно поэтому в 1 главе нашего исследования появился раздел, посвященный особенностям американского и еврейского юмора. Во 2 главе, прежде чем приступать непосредственно к анализу сборников, мы попытались вкратце определиться со спецификой рассказа как жанра и обрисовать историко-литературный контекст его развития в американской культуре. Проведен анализ сборников, в ходе которого мы выявили, что ведущий прием в рассказах – ирония. Мы также выявили, что сюжеты рассказов можно поделить на 6 типов, каждому из которых соответствует свой ведущий прием. Заголовки рассказов можно разделить на 3 типа, каждый из которых строится на комическом совмещении высокого и низкого, но превалирует в каждом то бурлескное, то травестийное начало. 3 глава нашего исследования посвящена изучению драматического наследия Аллена, которое не так велико, всего 6 пьес, из которых подробно нами были проанализированы только 3, вошедшие в сборник «Риверсайд-Драйв». Ведущий пример здесь – ирония В приложении приводится выдержка из интервью Вуди Аллена, оформленного в виде книги «Вуди Аллен: интервью со Стигом Бьйоркманом».

Организация потребительского кредитования на примере ПАО “Сбербанк России” : магистерская диссертация / Consumer lending organization on the example of PJSC “Sberbank of Russia”

Иванов, Г. О., Ivanov, G. O. January 2018 (has links)
The purpose of the master's thesis is to analyze consumer lending in the DO 7003/440 Sberbank of Russia and to develop proposals and recommendations for its improvement. In accordance with the stated goal, the following tasks were set in the work, which determined its internal logic and structure: - explore the economic essence of consumer lending; - identify the regulatory legal acts regulating relations in the field of consumer credit (loan); - to characterize the procedure for lending to the population on materials from DO 7003/440 of Sberbank of Russia; - to consider the existing shortcomings in the development of the consumer credit system in Sberbank Russia DO 7003/440; - study the legal documents on the organization of consumer lending in the DO 7003/440 Sberbank of Russia; - develop proposals for improving lending to the population in the bank and assess the effectiveness of the proposed measures; - present directions for improving legislative regulation in the field of consumer lending. The object of the research master's thesis is up to 7003/440 Sberbank of Russia. The subject of the study is the lending process. The theoretical and methodological basis of the work consists of the works of leading domestic economists, revealing the laws governing the development of credit portfolio management in a market economy. The laws and codes of the Russian Federation, resolutions of the Central Bank of the Russian Federation, the work of domestic authors in the field of banking, banking operations and law, such as G.G. Korobova, O.I. Lavrushin, I.T. Balabanova and others. The master thesis consists of introduction, three chapters, conclusion, list of references. In the theoretical part, the following provisions are disclosed: the content, nature, consumer lending of a commercial bank. The main theoretical aspects of consumer lending management are presented. Considered regulatory acts governing relations in the field of consumer credit (loan). In the second chapter, the organization of consumer loans in PJSC "Ural Bank of Sberbank of Russia" (UP 7003/440) is considered. The results of the analysis of consumer credit management are presented. Considered legal documents on the organization of consumer lending in DO 7003/440 Sberbank of Russia. The third chapter developed ways to improve the management of consumer lending at a commercial bank and presented the economic effect of the proposed measures, and also suggested ways to improve legislative regulation in the field of consumer lending. The information base of the study was the materials of commercial banks and other credit institutions of Russia, financial statements. In the course of the work, regulatory documents, statistical materials of the Central Bank of the Russian Federation and Russian information agencies, periodicals, as well as methodological developments of commercial banks were used. / Целью магистерской диссертации является анализ потребительского кредитования в ДО 7003/440 Сбербанка России и разработка предложений и рекомендаций по его совершенствованию. В соответствии с выдвинутой целью в работе поставлены следующие задачи, определившие ее внутреннюю логику и структуру: исследовать экономическую сущность потребительского кредитования; обозначить нормативно-правовые акты, регулирующие отношения в сфере потребительского кредита (займа); охарактеризовать порядок кредитования населения на материалах ДО 7003/440 Сбербанка России; рассмотреть существующие недостатки развития системы потребительского кредитования в ДО 7003/440 Сбербанка России; изучить правовые документы по организации потребительского кредитования в ДО 7003/440 Сбербанка России; разработать предложения по совершенствованию кредитования населения в банке и оценить эффективность предложенных мероприятий; представить направления совершенствования законодательного регулирования в сфере потребительского кредитования. Объектом исследования магистерской диссертации является ДО 7003/440 Сбербанка России. Предмет исследования – процесс кредитования. Теоретическую и методологическую основу работы составили труды ведущих отечественных экономистов, раскрывающие закономерности развития управления кредитным портфелем в условиях рыночной экономики. В качестве теоретической и информационной базы исследования были использованы законы и кодексы РФ, постановления Центрального Банка РФ, работы отечественных авторов в области банковского дела, банковских операций и права, таких как Г.Г. Коробова, О.И. Лаврушин, И.Т. Балабанова и других. Магистерская диссертация состоит из введения, трех глав, заключения, списка использованных источников. В теоретической части раскрыты следующие положения: содержание, сущность, потребительского кредитования коммерческого банка. Представлены основные теоретические аспекты управления потребительским кредитованием. Рассмотрены нормативно-правовые акты, регулирующие отношения в сфере потребительского кредита (займа). Во второй главе рассмотрена организация потребительского кредитования в ПАО «Уральский банк Сбербанка России» (ДО 7003/440). Представлены результаты анализа управления потребительским кредитованием. Рассмотрены правовые документы по организации потребительского кредитования в ДО 7003/440 Сбербанка России В третьей главе разработаны пути совершенствования управления потребительским кредитованием коммерческого банка и представлен экономический эффект от предложенных мероприятий, а также предложены пути совершенствования законодательного регулирования в сфере потребительского кредитования. Информационной базой исследования послужили материалы коммерческих банков и других кредитных институтов России, финансовая отчетность. В процессе работы были использованы нормативные документы, статистические материалы Центрального банка РФ и российских информационных агентств, периодической печати, а также методические разработки коммерческих банков.

Master's thesis of Tianshi Zhang / Electrochemical and Chemical Methods for the Fabrication of Nanocomposites

Zhang, Tianshi January 2016 (has links)
Novel electrocchemical and chemical strategies have been developed for the fabrication of functional nanocomposites. New scientific and engineering contribution of this work to colloidal nanotechnology included the development of advanced chelating dispersing agents, such as various small organic molecules and chelating polymers. The unique feature of such dispersion agents is their strong adsorption on the surface of different materials, which allows superior dispersion. The chelating monomers of chelating polymers, such as PAZO and PMSS provided multiple adsorption sites for bonding to metal atoms on the particles surface. We analyzed and developed new fundamental adsorption and dispersion mechanisms. An important finding was the possibility of co-dispersion and co-deposition of advanced materials such as oxides, nitrides, complex oxides and minerals using universal dispersing agents and formation of composites by EPD method. It was found that Caffeic acid (CA) can be used as an efficient dispersing agent for the synthesis of ZnO nanorods of reduced size and a dispersing agent for the EPD of ZnO films. Another important achievement of this work was the application of tannic acid as an efficient capping and dispersing agent for synthesis and EPD of inorganic materials and composites. An important discovery was the use of lauryl gallate dispersant as a reducing agent for the synthesis of AgNp and a vehicle for particle dispersion and extraction in the liquid-liquid extraction method. Further advancements in our new technologies allowed us to develop composite films using anodic EPD using weak polyelectrolytes, such as alginate. The composite coatings exhibited protective and flame retardant properties. We analyzed the deposition mechanisms and kinetics as well as microstructure of the coatings. In another strategy, we developed electrochemical strategies for the deposition of composites, based on strong polyelectrolytes. The approach is based on the EPD of the polyelectrolyte molecules and electrosynthesis of EPD of ceramic particles. The electrostatic heterocoagulation mechanism was proposed for the deposit formation. We investigated the deposition kinetics, composition and microstructure of the composites prepared by the new strategies. The new electrochemical strategies can be used for the deposition of other composites, based on functional polymers with pH independent charge. New methods have been developed for the chemical synthesis of PPy based composites, using PMSS, PMSS–SR11 and PMSS–SR31 as anionic dopants for chemical polymerization and dispersants for MWCNT. The composites showed promising performance for application in electrodes of electrochemical supercapacitors. Good electrochemical performance was achieved at high active mass loadings. The electrodes showed high capacitance, large voltage window and low impedance. The analysis of electrochemical testing results and chemical structure of PMSS, PMSS–SR11 and PMSS–SR31 provided an insight into the influence of the anionic functional groups on the capacitance and capacitance retention a high charge-discharge rates. / Thesis / Master of Applied Science (MASc)

I've Been Reading About Disaster Lately

McMurtray, Lisa Catherine 12 May 2012 (has links)
I’ve Been Reading About Disaster Lately is a collection of original poetry which focuses on how identity and agency are shaped through personal and public circumstance, through the intersection of the human and animal, and through the development of language and personal mythology. This collection is preceeded by a critical introduction which analyzes how poets mediate public and private disaster. The introduction specifially focuses on the eight poems written by Bob Hicok in the aftermath of the Virginia Tech Shooting, and examines how language, either in its presence or absence, functions to resolve the disconnect between pre-disaster and post-disaster.

Структура и динамика решетки редкоземельных германатов R2Ge2O7 (R=Tb-Lu, Y) : магистерская диссертация / Crystal structure and lattice dynamics of rare-earth germanates R2Ge2O7 (R=Tb-Lu, Y)

Рюмшин, В. С., Ryumshin, V. S. January 2020 (has links)
Германаты R2Ge2O7 (R=Tb-Lu, Y) имеют широкую область применения благодаря многообразию свойств, в том числе, благодаря оптическим свойствам. Кристаллическая структура этих соединений изучена достаточно хорошо, в то время как экспериментальных данных по фононным спектрам и упругим постоянным нет. В научной печати имеются только данные об ИК и КР спектрах поликристаллического образца Y2Ge2O7, из которых были определены частоты менее половины фононных мод. В связи с этим представляется актуальным провести первопринципное исследование структуры и динамики ряда R2Ge2O7 (R=Tb-Lu, Y). В работе в рамках единого ab initio подхода были проведены расчеты кристаллической структуры, частот и интенсивностей ИК и КР спектров, а также упругих постоянных R2Ge2O7. Из анализа векторов смещений, полученных из первопринципного расчета, определена степень участия ионов в каждой моде. Расчет фононных спектров и упругих постоянных для редкоземельных германатов R2Ge2O7 выполнен впервые. Расчеты проводились в рамках теории функционала плотности с гибридным функционалом PBE0, который учитывает локальный и нелокальный (в формализме Хартри-Фока) обмен, а также межэлектронные корреляции. Такой подход надежно опробован для сложных соединений с ионной и ионно-ковалентной связью. Расчеты были проведены в программе CRYSTAL17, предназначенной для моделирования периодических структур в рамках МО ЛКАО подхода. Результаты расчетов R2Ge2O7 хорошо согласуются с экспериментальными данными по кристаллической структуре, а также с имеющимися данными по ИК и КР спектрам для Y2Ge2O7. Расчеты позволили определить типы мод в измеренных спектрах иттриевого германата, а также описать изменение частот фононных мод и упругих свойств соединений R2Ge2O7 в ряду R=Tb-Lu. / Germanates R2Ge2O7 (R = Tb-Lu, Y) have a wide area of applications due to the variety of properties, including optical properties. The crystal structure of these compounds has been studied quite well, but there are no experimental data of phonon spectra and elastic constants. In the articles only the IR and Raman spectra of the polycrystalline Y2Ge2O7 are available, from which the frequencies of less than half of the phonon modes were determined. In this regard, it seems actual to conduct ab-initio study of the structure and dynamics of the row R2Ge2O7 (R = Tb-Lu, Y). In the framework of a single ab initio approach were calculated the crystal structure, frequencies and intensities of the IR and Raman spectra and elastic constants of R2Ge2O7. From the analysis of displacement vectors obtained from an ab-initio calculation, the degree of participation of ions in each mode is determined. The calculation of phonon spectra and elastic constants for rare-earth germanates R2Ge2O7 was performed for the first time. The calculations were carried out in the framework of the density functional theory with the PBE0 hybrid functional, which takes into account local and nonlocal (in the Hartree-Fock formalism) exchange, as well as interelectronic correlations. This approach has been reliably tested for complex compounds with ion and ion-covalent bonds. The calculations were carried out in the CRYSTAL17 program, designed to simulate periodic structures within the framework of the MO LCAO approach. The results of calculations of R2Ge2O7 are in good agreement with the experimental data of the crystal structure and with the available data of IR and Raman spectra for Y2Ge2O7. The calculations made it possible to determine the types of modes in the measured spectra of yttrium germanate and to describe the change in the frequencies of the phonon modes and the elastic properties of R2Ge2O7 compounds in the row R = Tb-Lu.

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