Blaise Ravelo

Bio: Blaise Ravelo is an academic researcher from Nanjing University of Information Science and Technology. The author has contributed to research in topic(s): Group delay and phase delay & Microstrip. The author has an hindex of 21, co-authored 196 publication(s) receiving 1727 citation(s). Previous affiliations of Blaise Ravelo include École Supérieure d'Ingénieurs en Génie Électrique & Nanjing University.

Active Microwave Circuit With Negative Group Delay

Abstract: In this letter, we report on the design, simulation and implementation of an active negative group delay circuit that operates at 1 GHz with a group delay and a gain, respectively, around 2 ns and 2 dB. Analytical formulas are proposed to demonstrate that the adopted topology is able to simultaneously achieve negative group delay (NGD) and gain while fulfilling active device constraints. The theoretical and simulated results are both validated by frequency measurements of a two-stage active microwave circuit.

Synthesis of Broadband Negative Group Delay Active Circuits

Abstract: This paper deals with the design and synthesis of active circuits able to simultaneously produce negative group delay and gain at microwave frequencies or for baseband signals Analytical equations show that the proposed topology meets these objectives while also satisfying active device requirements Then, a synthesis approach is extracted and applied to design a two-stage microwave circuit, further validated by experimental results This method is extended to the design of a four-stage baseband active circuit providing gain and negative group delay up to 600 MHz A high relative time-advance is evidenced by time-domain simulations

Demonstration of the triboelectricity effect by the flow of liquid water in the insulating pipe

Abstract: This paper demonstrates the tribolelectricity by the flow of water in an insulating pipe. A theoretical analysis showing the relation between the electric discharge and the system hydromechanical parameters is developed. Based on the macroscopic RC-circuit modeling of the system understudy, techniques allowing to minimize the discharge effect are introduced. With two different demonstrators, as predicted in theory, a voltage variation up to 300 mV is observed by using pipes having mm-diameter and pure water with 45 cm 3 s −1 flow rate. Finally, an application for the risk prevention caused by the explosion for the gas filling of engine fuel tank is discussed.

Application of negative group delay active circuits to the design of broadband and constant phase shifters

Abstract: The new phase-shifter configuration described in this report uses a negative group delay (NGD) active circuit. In this topology, a classical transmission line is set in cascade with an NGD circuit whose phase slopes are alike, but opposite, to get a constant and broadband phase shift. The proposed approach was validated through the design and measurement of a phase shifter, which exhibited a constant phase of 90° ± 5° over a 75% relative bandwidth around 1.6 GHz. Moreover, as the group delay of the NGD circuit compensated the transmission line one, the overall circuit group delay was kept to a small value in the operating frequency band. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3078–3080, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23883

Similitude between the NGD function and filter gain behaviours

Abstract: This paper deals with the similitude between the behaviours of linear filter gain and negative group delay NGD function. The transposition method of low-pass/high-pass, low-pass/band-pass and low-pass/band-stop NGD circuits is established. To the best of the author knowledge, it acts as the first paper devoted on the NGD function generalized theory. The introduced transform relationships simplify the synthesis of any NGD circuits from simple elementary low-pass NGD topologies. Families of innovative NGD topologies are identified. To verify the relevance of the concept proposed, frequency- and time-domain analysis results from realistic proofs of concept demonstrating the feasibility of developed NGD transforms were performed. Thanks to the NGD phenomenon, the possibility of the ultra-wideband pulse signals propagating in time-advance is verified. Finally, potential applications of NGD circuits are discussed. Copyright © 2013 John Wiley & Sons, Ltd.

Similarity and Dimensional Methods in Mechanics

Abstract: By L I Sedov London: Cleaver-Hume Press Ltd Pp xvi + 363 Price 105s This is really two separate books within the same pair of covers First of all Chapters 1-3, some 145 pages, are devoted to the discussion of similarity and dimensional, methods and their application to a variety of problems in mechanics and fluid mechanics

Lectures on Theoretical Physics

Abstract: Vorlesungen uber theoretische Physik Von Prof. Arnold Sommerfeld. Band 1: Mechanik. Vierte, neubearbeitete Auflage. Pp. xii + 276. 18 D. marks. Band 2: Mechanik der deformierbaren Medien. Pp. xv + 376 + 4 plates. 18 D. marks. Band 3: Elektrodynamik. Pp. xvi + 368. 18 D. marks. Band 6: Partielle Differentialgleichungen der Physik. Pp. xiii + 332. 18 D. marks. (Wiesbaden: Dieterich'sche Verlagsbuchhandlung, 1947–1949.)

Harvesting Water Drop Energy by a Sequential Contact-Electrification and Electrostatic-Induction Process

Abstract: A new prototype triboelectric nanogenerator with superhydrophobic and self-cleaning features is invented to harvest water drop energy based on a sequential contact electrification and electrostatic induction process. Because of the easy-fabrication, cost-effectiveness, and robust properties, the developed triboelectric nanogenerator expands the potential applications to harvesting energy from household wastewater and raindrops.