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mathematics,physics,geometry,Математика,College,Pre-College,vestibular universidades,olimpiadas de matematicas,Mathematical Olympiad,Algebra Problems,Geometry Problems,High School Geometry,Trigonometry Problems,Descriptive Geometry,Problems In Calculus Of One Variable,ECUACIONES DIFERENCIALES,problemas de fisica,Problems On Physics,Linear Algebra,Problems In Elementary Mathematics,Inequalities,Mathematics for high school students,EXAMENS DE ADMISION ALGEBRA.
   

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domingo, 24 de dezembro de 2017

Problems in Physics: Vorobiev, PI Zubkov, GA Kutuzov and others; Ed. O. Ya. Savchenko. 3rd ed., Rev. and additional. - Novosibirsk: Novosibirsk State University, 1999. - 370 p., Ill.






Задачи по физике: Учеб. пособие / И. И. Воробьев, П. И. Зубков, Г. А. Кутузова и др.; Под ред. О. Я. Савченко. 3-е изд., испр. и доп. — Новосибирск: Новосибирский государственный университет, 1999
LINK
http://www.mediafire.com/file/md0a8nl8xy4ym7e/Savchenko.pdf

sexta-feira, 8 de dezembro de 2017

CEREMONIA PREMIACION XXVI OLIMPIADA DE MATEMATICAS RIOPLATENSE -DICIEMBRE 217

PERU CAMPEÃO DA XXVI OLIMPÍADA RIOPLATENSE-ARGENTINA 02 MEDALHAS DE OURO,05 MEDALHAS DE PRATA

                                MEDALHAS DE OURO


                                                      
                                MEDALHAS DE PRATA



Escolares peruanos se coronan campeones internacionales de matemáticas en OLIMPIADA RIO PLATENSE ARGENTINA DICIEMBRE 2017


Con dos medallas de oro y 5 de plata, la delegación de escolares peruanos se coronó campeona de la 26 Olimpiada de Matemáticas Rioplatense 2017, que se desarrolló del 2 al 7 de diciembre en Argentina.
 Este triunfo peruano se logró gracias al talento y dedicación de nueve escolares, de colegios públicos y privados, quienes se impusieron a representantes de países como Brasil, Chile, Uruguay, Colombia y la propia Argentina, entre los más destacados.
 La selección campeona está integrada por Mijail Gutiérrez (oro), Roberts Antayhua (plata) y Flor Luna, en el primer nivel; Joseph Altamirano (plata), Eduardo Llamoca (plata) y Kenny Espejo, en segundo nivel; finalmente, en el tercer nivel, Anthony Yataco (oro), Luis Chahua (plata) y César Gutiérrez.
 Los campeones absolutos fueron Anthony Yataco y Mijail Gutiérrez, quienes lograron el más alto puntaje en sus respectivas categorías, y se hicieron acreedores de la máxima distinción de la competencia. Nueva promesa Con tan solo 13 años, Mijail ganó la medalla de oro en su primera participación en esta reconocida olimpiada, que convoca cada año a los mejores estudiantes de matemática de la región. “Me siento muy emocionado por haber alcanzado esta medalla y agradezco el apoyo de mi familia y de mi colegio Saco Oliveros, que me han ayudado a creer en mí mismo”, manifestó. Por otro lado, cabe destacar que César Gutiérrez fue el único de la delegación que pertenece a un colegio público. Él es estudia en el colegio Jorge Basadre de Trujillo. De la misma ciudad, pero del colegio Lobachesky es Kenny Espejo. Además de Mijail, Roberts Antayhua, Joseph Altamirano, Eduardo Llamoca y Luis Chahua son estudiantes del colegio Saco Oliveros. Por su parte, Anthony Yataco y Flor Luna son de colegio Prolog. Todos ellos se ganaron el derecho de representar al Perú en la Olimpiada Nacional Escolar de Matemática, organizada por el Ministerio de Educación (Minedu), entidad que, como en anteriores oportunidades, asumió los gastos de los pasajes de la delegación de matemática conformada por nueves estudiantes y tres profesores. Los representantes de la delegación peruana informaron que los campeones retornarán al Perú hoy jueves a las 10.15 horas. LINK ORIGINAL
https://publimetro.pe/actualidad/noticia-escolares-peruanos-se-coronan-campeones-internacionales-matematicas-68288

quarta-feira, 6 de dezembro de 2017

Doctoral Thesis A Study on High Efficiency Bidirectional Grid-tied Converters -Sung-Ho Lee (이 성 호) Department of Electrical Engineering Pohang University of Science and Technology






Doctoral Thesis 
A Study on High Efficiency Bidirectional Grid-tied Converters Sung-Ho Lee (이 성 호) 
Department of Electrical Engineering Pohang University of Science and Technology 2016 

ABSTRACT 
This thesis presents three high efficiency grid-tied converter topologies and their respective control algorithms. These converters are applicable to various industrial fields such as energy storage systems (ESS), renewable energy systems, uninterruptible power supply (UPS) systems, and electric vehicles (EV). First, a high efficiency bidirectional grid-tied flyback converter that uses a single power conversion technique and a control system for it are introduced. The proposed converter consists of a bidirectional flyback dc-dc converter and an unfolding circuit. Due to its switching control strategy, the proposed converter performs bidirectional power conversion between the energy storage device and the grid through only single step. From the model analysis, the inherent dynamic characteristics are figured out. Based on the analysis, a control system is developed, which consists of a linear feedback controller with a low pass filter, a repetitive controller, and a feed-forward controller; this overcomes the constrains caused by a right-half-plane zero and a filter resonance and makes the proposed converter achieve the desired control performances and stability. In conclusion, the proposed converter can obtain high efficiency using a single power conversion technique, and the developed control system makes the proposed converter feasible. Second, a high efficiency single-phase bidirectional inverter for a PV energy system integrated with an energy storage system. The proposed single-phase inverter is developed using the transformerless system configuration so that it provides high power conversion efficiency, excellent power density, and low production cost. Using its circuit structure and switching operation, the proposed inverter can suppress the ground leakage current which is considered to be one of the most important design parameters in a transformerless PV system. Therefore, the proposed inverter gives the feasibility for the transforemrless system configuration in a PV energy system integrated with an energy storage system and enhances the overall performance of the bidirectional power converter system. The third is a novel high efficiency three-phase bidirectional grid-tied converter with high power density for high power applications. The proposed converter is composed of the threelevel dc-dc converter and the modified three-phase T-type three-level inverter. The threelevel converter circuit configuration gives smaller passive component size and lower switch voltage stress compared to other two-level grid-tied converters. In addition, due to its novel circuit structure, the proposed converter can use the active and passive components for only two phases of the grid in the inverter stage and eliminate the leakage current problem. Thus, because the proposed converter enables to not only decrease the number of components but also make the transformerless configuration feasible, it provides higher efficiency and higher power density compared to other high power grid-tied converters. All proposed converters are analyzed theoretically, and implemented practically.