A CuBr-Based Brightness Amplifier with a Repetition Frequency of Superradiance/Amplification Pulses up to 200 kHz

AbstractTime-resolved photoelectron spectroscopy can give insights into carrier dynamics and offers the possibility of element and site-specific information through the measurements of core levels. In this paper, we demonstrate that this method can access electrons dynamics in PbS quantum dots over a wide time window spanning from pico- to microseconds in a single experiment carried out at the synchrotron facility BESSY II. The method is sensitive to small changes in core level positions. Fast measurements at low pump fluences are enabled by the use of a pump laser at a lower repetition frequency than the repetition frequency of the X-ray pulses used to probe the core level electrons: Through the use of a time-resolved spectrometer, time-dependent analysis of data from all synchrotron pulses is possible. Furthermore, by picosecond control of the pump laser arrival at the sample relative to the X-ray pulses, a time-resolution limited only by the length of the X-ray pulses is achieved. Using this method, we studied the charge dynamics in thin film samples of PbS quantum dots on n-type MgZnO substrates through time-resolved measurements of the Pb 5d core level. We found a time-resolved core level shift, which we could assign to electron injection and charge accumulation at the MgZnO/PbS quantum dots interface. This assignment was confirmed through the measurement of PbS films with different thicknesses. Our results therefore give insight into the magnitude of the photovoltage generated specifically at the MgZnO/PbS interface and into the timescale of charge transport and electron injection, as well as into the timescale of charge recombination at this interface. It is a unique feature of our method that the timescale of both these processes can be accessed in a single experiment and investigated for a specific interface.

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Effects of Non-thermal Ultrasound on a Fibroblast Monolayer Culture: Influence of Pulse Number and Pulse Repetition Frequency

Sensors ◽

10.3390/s21155040 ◽

2021 ◽

Vol 21 (15) ◽

pp. 5040

Author(s):

Silvia Ronda Peñacoba ◽

Mar Fernández Gutiérrez ◽

Julio San Román del Barrio ◽

Francisco Montero de Espinosa

Keyword(s):

Short Pulse ◽

Pulse Repetition Frequency ◽

Pulse Number ◽

Repetition Frequency ◽

Pulse Repetition ◽

Treatment Protocols ◽

Culture Plate ◽

New Treatment ◽

Long Pulse

Despite the use of therapeutic ultrasound in the treatment of soft tissue pathologies, there remains some controversy regarding its efficacy. In order to develop new treatment protocols, it is a common practice to carry out in vitro studies in cell cultures before conducting animal tests. The lack of reproducibility of the experimental results observed in the literature concerning in vitro experiments motivated us to establish a methodology for characterizing the acoustic field in culture plate wells. In this work, such acoustic fields are fully characterized in a real experimental configuration, with the transducer being placed in contact with the surface of a standard 12-well culture plate. To study the non-thermal effects of ultrasound on fibroblasts, two different treatment protocols are proposed: long pulse (200 cycles) signals, which give rise to a standing wave in the well with the presence of cavitation (ISPTP max = 19.25 W/cm2), and a short pulse (five cycles) of high acoustic pressure, which produces a number of echoes in the cavity (ISPTP = 33.1 W/cm2, with Pmax = 1.01 MPa). The influence of the acoustic intensity, the number of pulses, and the pulse repetition frequency was studied. We further analyzed the correlation of these acoustic parameters with cell viability, population, occupied surface, and cell morphology. Lytic effects when cavitation was present, as well as mechanotransduction reactions, were observed.

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Naphtha cracking through a pulsed DBD plasma reactor: Effect of applied voltage, pulse repetition frequency and electrode material

Chemical Engineering Journal ◽

10.1016/j.cej.2012.02.031 ◽

2012 ◽

Vol 191 ◽

pp. 416-425 ◽

Cited By ~ 48

Author(s):

A. Jahanmiri ◽

M.R. Rahimpour ◽

M. Mohamadzadeh Shirazi ◽

N. Hooshmand ◽

H. Taghvaei

Keyword(s):

Electrode Material ◽

Applied Voltage ◽

Voltage Pulse ◽

Pulse Repetition Frequency ◽

Plasma Reactor ◽

Repetition Frequency ◽

Pulse Repetition ◽

Dbd Plasma ◽

Applied Voltage Pulse

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Aqueous Benzene Oxidation in Low-Temperature Plasma of Pulsed Corona Discharge

Journal of Advanced Oxidation Technologies ◽

10.1515/jaots-2016-0212 ◽

2016 ◽

Vol 19 (2) ◽

Cited By ~ 1

Author(s):

Iakov Kornev ◽

Sergei Preis

Keyword(s):

Low Temperature ◽

Corona Discharge ◽

Gas Phase ◽

Pulse Repetition Frequency ◽

Repetition Frequency ◽

Pulse Repetition ◽

Benzene Oxidation ◽

Low Temperature Plasma ◽

Temperature Plasma ◽

Pulsed Corona

AbstractWastewaters polluted with non-biodegradable volatile organic compounds (VOCs), such as aromatic substances, present a growing problem meeting no adequately affordable technological response. Low-temperature plasma generated in the gas-phase pulsed corona discharge (PCD) presents competitive advanced oxidation technology in abatement of various classes of pollutants, although the process parameters, the pulse repetition frequency and the liquid spray rate, require optimization. The experimental research into aqueous benzene oxidation with PCD was undertaken to establish the impact of the parameters to the energy efficiency. The oxidation reaction was found under the experimental conditions to mostly proceed in the gas phase showing little influence of the pulse repetition frequency and the gas-liquid contact surface. Oxidation of benzene and, presumably, other volatile pollutants in the volume of PCD reactor compartment presents an effective strategy of aqueous VOCs abatement.

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