Photoacoustic Study of The Effect of 0.9 eV Light Illumination in Semi-Insulating GaAs

1997 ◽  
Vol 484 ◽  
Author(s):  
Atsuhiko Fukuyama ◽  
Yoshito Akashi ◽  
Kenji Yoshino ◽  
Kouji Maeda ◽  
Tetsuo Ikari
Keyword(s):  
Optical Absorption ◽  
Photon Energy ◽  
Metastable State ◽  
Energy Region ◽  
Broad Peak ◽  
Light Illumination ◽  
Transformation Rates ◽  
The Difference ◽  
First Time ◽  
Absorption Measurements

AbstractThe effect of the secondary light illumination of hv = 0.9 eV on the photoquenched and the enhanced states in semi-insulating GaAs are investigated by using piezoelectric photoacoustic (PPA) measurements at 80 K. It is found that the secondary light causes an optical recovery from EL2* to EL2° and this is in agrezment with the result reported by using infrared optical absorption measurements. We observed a broad peak around 0.9 eV after the secondary light illumination for the first time. The most important finding is that the PPA spectra after the secondary light illumination on the quenched and the enhanced states are the same in the whole photon energy region. We concluded that the secondary light of hv = 0.9 eV induces both an optical recovery and generation of metastable state of the EL6 level. The difference of the transformation rates of these two processes explains well the observed complex natures of the PPA signal under the secondary light illumination.

Photovoltaic effect of Sn2P2S6 ferroelectric crystal and ceramics

2001 ◽  
Vol 16 (11) ◽  
pp. 3317-3322 ◽  
Author(s):  
Y. W. Cho ◽  
S. K. Choi ◽  
Yu. M. Vysochanskii
Keyword(s):  
Ceramic Sample ◽  
Remanent Polarization ◽  
Photovoltaic Effect ◽  
Ferroelectric Ceramics ◽  
Infrared Light ◽  
Light Illumination ◽  
Ferroelectric Crystal ◽  
The Difference ◽  
First Time ◽  
Perovskite Type

To investigate the photovoltaic effect in Sn2P2S6 ferroelectrics, Sn2P2S6 crystal and ceramic sample that had a high relative density of 95% and a grain size of below 1 μm were fabricated. The steady-state photovoltaic currents under infrared light illumination on both Sn2P2S6 crystal and ceramic sample were observed for the first time. The photovoltaic currents ipv on Sn2P2S6 ceramic sample and crystal were 5 and 25 nA/cm, respectively. The difference in the magnitude of the photovoltaic current resulted from the difference in the remanent polarization Pr between the crystal and the ceramic sample. The values of the photovoltaic field Epv determined from I–V curve for Sn2P2S6 ceramic sample and crystal were 0.2 and 6 V/cm, respectively; these values were several orders lower than that observed on the perovskite-type ferroelectric ceramics. The photovoltaic fields observed in this study were discussed with the conductivity of the crystal and the ceramic sample, in consideration of the figure of merit for the photostriction.

RESONANT AUGER SPECTRA OF Kr NEAR THE L3 THRESHOLD

2002 ◽  
Vol 09 (01) ◽  
pp. 85-88 ◽  
Author(s):  
T. IBUKI ◽  
K. OKADA ◽  
K. KAMIMORI ◽  
J. SASAKI ◽  
H. YOSHIDA ◽  
...  
Keyword(s):  
Photon Energy ◽  
Energy Region ◽  
Auger Electron ◽  
Electron Spectra ◽  
Auger Spectra ◽  
Resonant Transitions ◽  
First Time ◽  
Auger Electron Spectra

Auger electron spectra were studied by scanning the photon energy near the L 3 threshold of krypton. Two resonant transitions were observed in the photon energy region 1673–1678 eV for the first time. They were identified to be the resonant 3d -2 5s and 3d -2 4d states originating in the 2p 3/2-1 5s and 2p 3/2-1 4d excitations, respectively.

scholarly journals HI 21cm-line Observations with the GMRT Towards Interstellar Clouds Previously Seen in Optical Absorption

2002 ◽  
Vol 199 ◽  
pp. 341-342
Author(s):  
R. Mohan ◽  
K.S. Dwarakanath ◽  
G. Srinivasan ◽  
J.N. Chengalur
Keyword(s):  
Optical Absorption ◽  
Absorption Lines ◽  
Interstellar Clouds ◽  
Random Velocity ◽  
Line Absorption ◽  
The Galaxy ◽  
The Mean ◽  
First Time ◽  
Absorption Features ◽  
Absorption Measurements

We have made HI 21cm-line absorption measurements using the GMRT towards 15 directions in the Galaxy which are known to have high random velocity clouds as seen in the optical absorption lines of CaII and NaI. For the first time, in 6 out of these 15 directions we detect HI absorption features corresponding to the high random velocity optical absorption lines. The mean optical depth of these detections is ∼ 0.08.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

Strategies for Oral Delivery of Metal-Saturated Lactoferrin

2019 ◽  
Vol 20 (11) ◽  
pp. 1046-1051 ◽  
Author(s):  
Przemysław Gajda-Morszewski ◽  
Klaudyna Śpiewak-Wojtyła ◽  
Maria Oszajca ◽  
Małgorzata Brindell
Keyword(s):  
Biological Activity ◽  
Oral Delivery ◽  
Therapeutic Potential ◽  
Structure And Function ◽  
The Difference ◽  
And Function ◽  
First Time

Lactoferrin was isolated and purified for the first time over 50-years ago. Since then, extensive studies on the structure and function of this protein have been performed and the research is still being continued. In this mini-review we focus on presenting recent scientific efforts towards the elucidation of the role and therapeutic potential of lactoferrin saturated with iron(III) or manganese(III) ions. The difference in biological activity of metal-saturated lactoferrin vs. the unmetalated one is emphasized. The strategies for oral delivery of lactoferrin, are also reviewed, with particular attention to the metalated protein.

Nokhri, Ger, and the Art of Separation in the Hebrew Bible

2018 ◽  
Author(s):  
Adi Ophir ◽  
Ishay Rosen-Zvi
Keyword(s):  
Hebrew Bible ◽  
Biblical Literature ◽  
The Difference ◽  
First Time

This chapter traces the developments of various terms denoting “others” in biblical literature. In much of the biblical corpus, Israel is still one goy among many, and the difference between it and its Others is neither binary nor stable. After a brief analysis of the dynamics of familial and ethnwic separations in Genesis and Exodus, this chapter concentrates on the priestly and Deuteronomistic modes of separating peoples, examines the novelty and limitedness of the Deuteronomistic legislation, where the nokhri (stranger) is systematically contrasted for the first time with the Israelite (referred to as “your brother”), and follows the various modes of separations and their rationales.

Species diversity and abundance of Dacus (Diptera: Tephritidae) in five ecosystems of Penang, West Malaysia

1982 ◽  
Vol 72 (4) ◽  
pp. 709-716 ◽  
Author(s):  
Tan Keng-Hong ◽  
Lee Soo-Lam
Keyword(s):  
Species Diversity ◽  
Capsicum Annuum ◽  
Fruits And Vegetables ◽  
Methyl Eugenol ◽  
Dacus Dorsalis ◽  
The Difference ◽  
Vegetable Farm ◽  
First Time

AbstractDacus dorsalis Hend. infested eleven, D. cucurbitae Coq. five and D. umbrosus F. two of the eighteen common fruits and vegetables grown in Penang, West Malaysia. D. tau (Wlk.) infested bacang (Mangifera foetida), D. caudatus F. chilli (Capsicum annuum) and D. frauenfeldi Schin. water guava (Eugenia javanica), together with D. dorsalis. Pomelo (Citrus grandis) was found infested for the first time by D. cucurbitae. No flies were trapped using Capilure and trimedlure as baits. Cue-lure attracted D. caudatus, D. cucurbitae, D. frauenfeldi, D. occipitalis (Bez.) and D. tau. Methyl eugenol attracted D. dorsalis and D. umbrosus. Dorsalure was less attractive to D. caudatus and D. dorsalis than cue-lure and methyl eugenol, respectively, but it was equally attractive to D. frauenfeldi as cue-lure. Using traps baited with cue-lure or methyl eugenol in five ecosystems, the highest numbers of males of D. dorsalis, D. umbrosus, D. frauenfeldi and D. caudatus trapped were from a village, on a vegetable farm for D. cucurbitae, and D. occipitalis was only caught in a forest. Analysis showed that for each species of Dacus the difference between ecosystems was highly significant. The few examples caught in grassland were probably migrants.

Dose-window dependence on Si crystal orientation in separation by implanted oxygen substrate formation

2004 ◽  
Vol 19 (12) ◽  
pp. 3607-3613 ◽  
Author(s):  
H. Iikawa ◽  
M. Nakao ◽  
K. Izumi
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Crystal Orientation ◽  
Oxygen Ion ◽  
The Difference ◽  
First Time ◽  
Good Agreement

Separation by implemented oxygen (SIMOX)(111) substrates have been formed by oxygen-ion (16O+) implantation into Si(111), showing that a so-called “dose-window” at 16O+-implantation into Si differs from Si(100) to Si(111). In SIMOX(100), an oxygen dose of 4 × 1017/cm2 into Si(100) is widely recognized as the dose-window when the acceleration energy is 180 keV. For the first time, our work shows that an oxygen dose of 5 × 1017/cm2 into Si(111) is the dose-window for the formation of SIMOX(111) substrates when the acceleration energy is 180 keV. The difference between dose-windows is caused by anisotropy of the crystal orientation during growth of the faceted buried SiO2. We also numerically analyzed the data at different oxidation velocities for each facet of the polyhedral SiO2 islands. Numerical analysis results show good agreement with the experimental data.

45° REFLECTOMETRY OF SEMICONDUCTOR QUANTUM WELLS

2001 ◽  
Vol 15 (17n19) ◽  
pp. 683-687
Author(s):  
A. SILVA-CASTILLO ◽  
F. PEREZ-RODRIGUEZ
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Growth Direction ◽  
Angle Of Incidence ◽  
Near Surface ◽  
New Information ◽  
Difference Formula ◽  
Exciton Polaritons ◽  
The Difference ◽  
First Time

We have applied the 45° reflectometry for the first time to study exciton-polaritons in quantum wells. The 45° reflectometry is a new polarization-modulation technique, which is based on the measurement of the difference [Formula: see text] between the p-polarization reflectivity (Rp) and the squared s-polarization reflectivity [Formula: see text] at an angle of incidence of 45°. We show that [Formula: see text] spectra may provide qualitatively new information on the exciton-polariton modes in a quantum well. These optical spectra turn out to be very sensitive to the zeros of the dielectric function along the quantum-well growth direction and, therefore, allow to identify the resonances associated with the Z exciton-polariton mode. We demonstrate that 45° reflectometry could be a powerful tool for studying Z exciton-polariton modes in near-surface quantum wells, which are difficult to observe in simple spectra of reflectivity Rp

Sign in / Sign up

Export Citation Format

Share Document