585 research outputs found
Projeto e simulação de amplificador de potência multimodos de alta potência e baixa variação de ganho
Get PDFOrientador: Prof. Bernardo Rego Barros de Almeida LeiteDissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia Elétrica. Defesa : Curitiba, 13/08/2021Inclui referências: p. 77-79Resumo: Um dos principais subsistemas responsáveis pela comunicação em radiofrequência em dispositivos móveis é o amplificador de potência (PA). O PA tem como função amplificar os sinais de baixa potência até a potência necessária para que esses sinais possam ser recebidos pelo receptor. Considerando-se a alta mobilidade desses dispositivos, diferentes níveis de potência podem ser necessários para a transmissão do sinal. Nesse projeto, é proposto um PA que possa entregar uma potência variável na saída, com foco na potência de saída e baixa variação de ganho na tecnologia CMOS 130 nm. O PA apresenta diferentes modos de operação que, além da potência de saída, também variam a potência consumida pelo circuito. Assim, a utilização de diferentes modos pode apresentar uma economia de energia, o que é um fator importante para dispositivos alimentados por baterias. No entanto, a tecnologia CMOS apresenta limitações para projetos que requerem uma alta potência, sendo necessárias diferentes estratégias para que se possa atingir maiores potências de saída. Nesse projeto foram utilizadas algumas dessas estratégias apresentadas na literatura, como a arquitetura diferencial e o empilhamento de transistores. O PA resultante é controlado por três sinais digitais, tendo quatro modos de operação diferentes, os quais apresentam um OCP1dB variando de 20,6 dBm a 24,6 dBm, um ganho direto que varia entre 30,8 dB e 31,7 dB e uma potência consumida que varia de 1,56 W a 2,61 W. Dessa forma, ao alterar-se entre modos de operação, pode-se atingir uma economia de até 40,2% na potência consumida pelo circuito.Abstract: One of the most important subsystems responsible for the radiofrequency communication in mobile devices is the power amplifier (PA). The PA amplifies the low-power signals to higher power levels so they can be transmitted and then received at the receptor. Considering the high mobility of the mobile devices, different power levels can be required for the signals to be transmitted. In this project a variable power PA is proposed, focusing in the output power and in low gain variation utilizing the 130 nm CMOS technology. The PA has different operation modes that besides the output power, they also present a different power consumption each. Therefore, the circuit can save energy consumption by utilizing different operation modes which is an important factor for devices supplied by batteries. However, the CMOS technology presents limitations to design circuits which requires a high power-level. Due to these limitations, different designs must be used to achieve higher output power levels. In this project some of the design strategies presented in the literature are utilized to improve the output power, like the differential architecture and the stacked transistors. The resulting circuit is PA controlled by three digital signals with four different operation modes which present a OCP1dB varying from 20.6 dBm until 24.6 dBm, a direct gain varying between 30.8 dB and 31.7 dB and a consumed power varying from 1.56 W to 2.61 W. By switching between the different operation modes, this PA can save up to 40.2% of the consumed power
Symposium on recent trend in the research of hyperlipidemia in Japan. (1). Profiles of primary hyperlipidemia in Japan.
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Author response image 1.
Get PDFNeurotransmitter is released at synapses by fusion of synaptic vesicles with the plasma membrane. To sustain synaptic transmission, compensatory retrieval of membranes and vesicular proteins is essential. We combined capacitance measurements and pH-imaging via pH-sensitive vesicular protein marker (anti-synaptotagmin2-cypHer5E), and compared the retrieval kinetics of membranes and vesicular proteins at the calyx of Held synapse. Membrane and Syt2 were retrieved with a similar time course when slow endocytosis was elicited. When fast endocytosis was elicited, Syt2 was still retrieved together with the membrane, but endocytosed organelle re-acidification was slowed down, which provides strong evidence for two distinct endocytotic pathways. Strikingly, CaM inhibitors or the inhibition of the Ca2+-calmodulin-Munc13-1 signaling pathway only impaired the uptake of Syt2 while leaving membrane retrieval intact, indicating different recycling mechanisms for membranes and vesicle proteins. Our data identify a novel mechanism of stimulus-and Ca2+-dependent regulation of coordinated endocytosis of synaptic membranes and vesicle proteins
N=2 supersymmetric dynamics for pedestrians
No full textUnderstanding the dynamics of gauge theories is crucial, given the fact that all known interactions are based on the principle of local gauge symmetry. Beyond the perturbative regime, however, this is a notoriously difficult problem. Requiring invariance under supersymmetry turns out to be a suitable tool for analyzing supersymmetric gauge theories over a larger region of the space of parameters. Supersymmetric quantum field theories in four dimensions with extended N=2 supersymmetry are further constrained and have therefore been a fertile field of research in theoretical physics for quite some time. Moreover, there are far-reaching mathematical ramifications that have led to a successful dialogue with differential and algebraic geometry. These lecture notes aim to introduce students of modern theoretical physics to the fascinating developments in the understanding of N=2 supersymmetric gauge theories in a coherent fashion. Starting with a gentle introduction to electric-magnetic duality, the author guides readers through the key milestones in the field, which include the work of Seiberg and Witten, Nekrasov, Gaiotto and many others. As an advanced graduate level text, it assumes that readers have a working knowledge of supersymmetry including the formalism of superfields, as well as of quantum field theory techniques such as regularization, renormalization and anomalies. After his graduation from the University of Tokyo, Yuji Tachikawa worked at the Institute for Advanced Study, Princeton and the Kavli Institute for Physics and Mathematics of the Universe. Presently at the Department of Physics, University of Tokyo, Tachikawa is the author of several important papers in supersymmetric quantum field theories and string theory
Seven connection patterns between the author research areas.
No full textSeven connection patterns between the author research areas.</p
Effects of phytic acid sorption on iron polymerization and at the ferrihydrite-water interface
Get PDFPhytic acid is the most predominant organic phosphorus species in soils. Its stability in soils is mainly due to its high affinity for soil colloids, especially Fe (oxyhydr)oxides. They have been acknowledged as mobile/reactive adsorbents for P in soil-water environments. Although several sorption mechanisms were proposed, it is not clear how multi phosphate groups of phytic acid contribute to the surface complexation and/or precipitation processes. In this study, sorption behavior of phytic acid in ferrihydrite was examined using experimental geochemistry, solution 31P nuclear magnetic resonance spectroscopy, X-ray diffraction and scanning electron microscopy. The results indicated inner-sphere surface complexation via P1,3 and P2 functional groups under both pH 5 and 8.5. Under alkaline pH, an additional P5 functional group became active. Coprecipitation experiments showed evidence of the formation of Fe(III)-phytate-like bulk precipitates when the initial phytic acid/Fe(III) molar ratio was high (0.45-0.5). At the low phytic acid/Fe(III) (<0.1), the formation of ferrihydrite was unaffected, but further transformation was still inhibited. The study suggests a new role of phytic acid in the formation of Fe oxyhydroxide minerals.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-05-01The student, Ai Chen, accepted the attached license on 2019-03-22 at 09:27.The student, Ai Chen, submitted this Thesis for approval on 2019-03-22 at 09:39.This Thesis was approved for publication on 2019-03-25 at 10:06.DSpace SAF Submission Ingestion Package generated from Vireo submission #13441 on 2019-08-22 at 16:20:26Made available in DSpace on 2019-08-23T20:44:35Z (GMT). No. of bitstreams: 2
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Previous issue date: 2019-03-25Embargo set by: Seth Robbins for item 112265
Lift date: 2021-08-23T20:44:50Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112265
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Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112265
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Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112265
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Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 112265 on 2021-08-24T09:15:10Z
Lipid composition of platelets from patients with atherosclerosis: Effect of purified eicosapentaenoic acid ethyl ester administration
No full textOBSERVATION OF THE BULB TYPE TILTMETER IN THE LANDSLIDES
No full textIn this paper, the author had studied thr relationship between variation of tiltineter andlandslide movement observing bulb type tiltmeters~ in the creep type landslides. From the resultsof them, the variation of tiltmeter in landslide is related with the landslide movement of creep type.When we make judge the landslide movement from variation of inclination on the soil surface, it is usefull to confer the standard curves that was maked by observational facts.The critical inclination for soil movement, is assumed about 4"/day as N-S and E-W com-ponent respectivelly.In this paper, the author had studied thr relationship between variation of tiltineter andlandslide movement observing bulb type tiltmeters~ in the creep type landslides. From the resultsof them, the variation of tiltmeter in landslide is related with the landslide movement of creep type.When we make judge the landslide movement from variation of inclination on the soil surface,it is usefull to confer the standard curves that was maked by observational facts.The critical inclination for soil movement, is assumed about 4"/day as N-S and E-W com-ponent respectivelly
Mesotomisation of Diammine=dinitro=oxalo=cobalt Complex and Determination of the Configurations of this Complex and of Diammine=tetranitro=cobalt Complex
No full text1. Diammine-dinitro-oxalo-cobalt complex [Co(NH3)2(NO2)2C2O4]Me has been resolved into the optically active isomers by fractionation of the salts of brucine, strychinine and cinchomine. 2. In the fractionation of the alkaloid salts of the complex, either the l-alkaloid-l-cobalt complex or d-alkaloid-d-cobalt complex was always found to separate out as the least soluble fraction, while either the l-alkaloid-d-cobalt complex or d-alkaloid-l-cobalt complex always contituted the most easily soluble fraction. 3. The specific rotations of potassium and ammonium diammine-dinitro-oxalo-cobaltiates, which have been obtained by replacing the alkaloid molecules with potassium-and ammonium ions respectively, were measured, and found to have the values of ca±115°, using sodium light. 4. As a results of the mesotomisation of diammine-dinitro-oxalo-cobalt complex, the configurations of this complex and also of its mother substance, diammine-tetranitro-cobalt complex, have been made clear, the possibility of mesotomisation indicating that the complex ion [Co(NH2)2(NO2)2C2O4] is constructed asymmetrically, which means that the two ammonia molecules in this complex ion occupy the adjacent spacial position. As to the two nitro-groups, their position was previously determined, by one of the authors (Shibata), by a spectroscopic study. 5. The molecular asymmetry of the above mentioned complex ion, which is the first example of a mesotomised complex anion containing a cobalt atom, belongs to a new type and has been introduced into the stereochemistry of the metal complexes, calling it the type of molecular asymmetry III, in extension of Werner\u27s classification. The senior author, Yuji Shibata, has profound sorrow in recording here the death of his collaborator Mr. Toshio Maruki, Rigakushi, which occurred during the progress of the investigation recorded in this paper. At the same time, he has much pleasure in expressing his hearty thanks to Messrs. K. Matsuno, Rigakushi, and S. Mitsukuri for the great assistance they have given him in completing this work
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