Investigation of Ultrafast Charge Carrier and Lattice Dynamics

2020 ◽  
Vol 29 (9) ◽  
pp. 7-10
Author(s):  
Kyungwan KIM
Keyword(s):  
Charge Carrier ◽  
Equilibrium State ◽  
Time Resolution ◽  
Material Properties ◽  
Time Scale ◽  
Lattice Dynamics ◽  
Detection Methods ◽  
Ultrafast Dynamics ◽  
Pulsed Lasers ◽  
Fundamental Interactions

When a material is driven out of an equilibrium state, fundamental interactions governing the material properties play roles in returning to the equilibrium state. The microscopic process of this recovery takes place on an ultrafast time scale far beyond the usual time resolution of usual detection methods. Thanks to the recent development of the ultrashort pulsed lasers, various ultrafast techniques are now available to investigate the ultrafast dynamics of materials. In this article, I briefly review the experiment techniques used to investigate ultrafast electronic and lattice dynamics.

scholarly journals Surface viscosity and Marangoni stresses at surfactant laden interfaces

2016 ◽  
Vol 792 ◽  
pp. 712-739 ◽  
Author(s):  
Gwynn J. Elfring ◽  
L. Gary Leal ◽  
Todd M. Squires
Keyword(s):  
Material Properties ◽  
Finite Time ◽  
Time Scale ◽  
Surfactant Concentration ◽  
Marangoni Flow ◽  
Force Measurements ◽  
Surface Viscosity ◽  
Surface Shear ◽  
Marangoni Force ◽  
Soluble Surfactant

We calculate here the force on a probe at a viscous, compressible interface, laden with soluble surfactant that equilibrates on a finite time scale. The motion of the probe through the interface drives variations in the surfactant concentration at the interface that in turn leads to a Marangoni flow that contributes to the force on the probe. We demonstrate that the Marangoni force on the probe depends non-trivially on the surface shear and dilatational viscosities of the interface indicating the difficulty in extracting these material properties from force measurements at compressible interfaces.

scholarly journals Dynamics of Primary Events in the Photocycle of Excited Bacteriorhodopsin

2004 ◽  
Vol 36 (11) ◽  
pp. 724-728 ◽  
Author(s):  
Jun-Jun Lu ◽  
Ming Ming ◽  
Yi Yang ◽  
Jia Wu ◽  
Bo Li ◽  
...  
Keyword(s):  
Dynamic Behavior ◽  
Time Scale ◽  
Excitation Wavelength ◽  
Ultrafast Dynamics ◽  
Medium Ph ◽  
Pump Probe ◽  
Dynamical Behaviors ◽  
Retinal Chromophore ◽  
Ph Dependent ◽  
The One

Abstract Transient dynamic behavior of the excited bacteriorhodopsin (BR), which was isolated from the strain H. salinarum, was studied at excitation wavelength from 585 to 639 nm. With the one-color femtosecond (fs) pump-probe technique, we revealed the primary events in BR's photocycle that took place in an ultrafast time scale. From the analysis of the decay components of the dynamical traces, it was evident that the isomerization of the retinal chromophore in BR and the intermediate J's formation occurred within 500 fs. BR exhibited pH-dependent dynamical behaviors. When the medium pH was between 5 and 9, the BR ultrafast dynamics has no obvious change. In contrast, the dynamical curves were obviously affected when the pH was out of that region.

Analysis of Alfvénic flows with Solar Orbiter: particle and magnetic observations down to kinetic scales.

2021 ◽  
Author(s):  
Philippe Louarn ◽  
Andrei fedorov ◽  
alexis Rouillard ◽  
Benoit Lavraud ◽  
Vincent Génot ◽  
...  
Keyword(s):  
Solar Wind ◽  
Fine Structure ◽  
Time Resolution ◽  
Time Scale ◽  
Residual Energy ◽  
Distribution Functions ◽  
Strongly Correlated ◽  
Temperature Anisotropy ◽  
Velocity Fluctuations ◽  
Turbulence Parameters

<p>The magnetic and velocity fluctuations of the solar wind may be strongly correlated. This characterizes the  ‘Alfvenic’ flows. Using the observations of the Proton Alfa sensor (PAS/SWA) and the magnetometer (MAG) onboard Solar Orbiter, we analyze a period of 100 hours of such alfvenic flows, at different scales. Several parameters of the turbulence are computed (V-B correlation, various spectral indexes, cross-helicity, residual energy). We explore how these parameters may vary with time and characterize different turbulent states of the flow. More specifically, using the unprecedented time resolution of PAS during burst mode, especially its capability to measure 3D distribution functions at time scale below the proton gyroperiod, we study the connection of the turbulence to the dissipation domain and analyze the fine structure of the distribution functions and their evolutions at sub-second scales. The goal is to investigate whether some characteristics of the distributions, as their more or less pronounced temperature anisotropy, may be related to the turbulence parameters and the degree of V-B correlation.</p>

scholarly journals A short-lived flare of EV Lacertae

1990 ◽  
Vol 137 ◽  
pp. 35-36
Author(s):  
B. E. Zhilyaev ◽  
Ya. O. Romanjuk ◽  
O. A. Svyatogorov
Keyword(s):  
Fine Structure ◽  
Light Curve ◽  
Time Resolution ◽  
Time Scale ◽  
High Time ◽  
High Time Resolution ◽  
Decay Times ◽  
Ev Lac

Flare events on a time scale of the order of one second were observed on EV Lac by Gershberg and Petrov [1], Zalinian and Tovmassian [2], Tsvetkov, Antov and Tsvetkova [3]. The nature of such phenomena is very mysterious. We hope that monitoring of EV Lac with high time resolution will yield the information about growing and decay times as well as fine structure of the light curve and color one. A short-lived flare of EV Lac was recorded in U and V bands in 1989, September 3 2h 14m 30s UT. The duration of the event was about 150 milliseconds.

Ultrafast dynamics of charge carrier photogeneration and geminate recombination in conjugated polymer:fullerene solar cells

2005 ◽  
Vol 72 (19) ◽  
Author(s):  
J. G. Müller ◽  
J. M. Lupton ◽  
J. Feldmann ◽  
U. Lemmer ◽  
M. C. Scharber ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Carrier ◽  
Ultrafast Dynamics ◽  
Geminate Recombination

Short time-scale variability in the spectrum of the hot B3V star ηUMa

2020 ◽  
Vol 10 (1) ◽  
pp. 3-6
Author(s):  
S. Pokhvala
Keyword(s):  
Time Resolution ◽  
Stellar Wind ◽  
Time Scale ◽  
Atmospheric Oxygen ◽  
Short Time Scale ◽  
Low Resolution ◽  
Balmer Lines ◽  
Hydrogen Lines ◽  
Short Time ◽  
Radial Pulsations

We report the results of observations of short time-scale variability in the Hydrogen Balmer lines and HeI lines in the hot B star ηUMa. Spectral observations were carried out with the low-resolution slitless spectrograph (R∼200) installed on the 60 cm Carl Zeiss telescope in the Andrushivka Observatory, Ukraine. Spectra were obtained with a time resolution in the sub-second range. It has been found that the hot B star ηUMa shows rapid variations in the Hydrogen lines Hβ, Hγ, Hδ, Hε and the Helium lines HeI 5016Å HeI 5047Å, as well as variations in the atmospheric oxygen lines. This can be interpreted that their variations are non-radial pulsations and strong stellar wind.

The Latest Version of SiFAP: Beyond Microsecond Time Scale Photometry of Variable Objects

2016 ◽  
Vol 05 (03) ◽  
pp. 1650005 ◽  
Author(s):  
F. Ambrosino ◽  
P. Cretaro ◽  
F. Meddi ◽  
C. Rossi ◽  
S. Sclavi ◽  
...  
Keyword(s):  
Binary System ◽  
Time Resolution ◽  
Time Scale ◽  
Single Photon ◽  
Time Windows ◽  
Time Of Arrival ◽  
Commercial Unit ◽  
Spin Period

Technical improvements of the Silicon Fast optical Astronomical Photometer (SiFAP) allow the instrumentation to integrate photons coming from the target in time windows down to 20[Formula: see text]s. Further hardware improvement has been implemented to tag the Time of Arrival ([Formula: see text]) of each single photon. In addition, a new commercial GPS unit has replaced the older commercial unit improving time resolution. The latest version of SiFAP has been calibrated to check photometric sensitivity and linearity through observations of several standard stars. SiFAP has been also successfully tested by observing the HZ/Her X-1 Binary System estimating the spin period of the pulsar (Her X-1). Our results have been then compared to data available in literature.

scholarly journals The Best possible Time resolution: How precise could a Radiocarbon dating method be?

Radiocarbon ◽  
2019 ◽  
Vol 61 (6) ◽  
pp. 1729-1740 ◽  
Author(s):  
I Svetlik ◽  
A J T Jull ◽  
M Molnár ◽  
P P Povinec ◽  
T Kolář ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Time Resolution ◽  
Calibration Curve ◽  
Time Scale ◽  
Radiocarbon Dating ◽  
Time Intervals ◽  
High Slope ◽  
Resolution Curve ◽  
Dating Method ◽  
Fine Time

ABSTRACTToday, accelerator mass spectrometry (AMS) technology enables us to carry out very precise measurements of radiocarbon (14C). Unfortunately, due to fluctuations in the 14C calibration curve, the resulting calibrated time intervals vary from decades up to centuries in calibrated age. Within a time scale of several decades, we can find several time intervals on the 14C calibration curve which correspond with periods of rapid increases in atmospheric 14CO2 activity. Some of these “high slope” parts of the calibration curve could be used for fine time resolution for radiocarbon dating of individual samples. Nevertheless, there are certain limitations owing to the properties of the samples measured. We have prepared a time-resolution curve for the 14C dating method, applying calibration curve IntCal13 and assuming an uncertainty of 14C analyses ±15 yr BP (for recent samples). Our curve of the time resolution covers the last 50 ka. We found several time intervals with time resolution below 50 yr BP for the last 3 ka. Several time intervals which can enable substantially better time resolution compared to neighboring parts of the calibration curve were also found for periods older than 3 ka.

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