Ruby Laser Induced Changes in the Absorption Spectra of Sodium Decorated Sodium Chloride Crystals

1970 ◽  
Vol 25 (2) ◽  
pp. 229-236
Author(s):  
H. Kuzmany
Keyword(s):  
Absorption Spectra ◽  
Ruby Laser ◽  
Laser Light ◽  
Temperature Treatment ◽  
Laser Wavelength ◽  
Beam Path ◽  
General Increase ◽  
Annealing Conditions ◽  
Different Depths ◽  
Induced Changes

Abstract The effects of intense Q-switched ruby laser light on the absorption spectra of NaCl crystals, additively coloured by colloidal sodium were investigated at different depths along the laser beam path as well as after being subjected to different annealing conditions. A strong general increase in absorption was observed in the region where the laser light entered the crystal, while a strong decrease in absorption occurred in the colloid band, especially around the laser wavelength. This bleaching was accompanied by the generation of a new absorption band at ~ 1200 nm (~1.0eV) in the infrared, which, according to its sensitivty to temperature treatment, is not of colloidal origin, The energy denisty necessary for its generation was found to be about 400mJ/cm2. Its is suggested that the bleaching of the colloid band could be used for the storage of holograms.

Laser-Induced Acoustic Waves for Measurement and Imaging

2000 ◽  
Author(s):  
Wen Li ◽  
Ronald A. Roy ◽  
Robin O. Cleveland ◽  
Lawrence J. Berg ◽  
Charles A. DiMarzio
Keyword(s):  
Acoustic Waves ◽  
Peak Power ◽  
Laser Light ◽  
Short Pulse ◽  
Laser Wavelength ◽  
Acoustic Imaging ◽  
Acoustic Energy ◽  
High Peak Power ◽  
First Case ◽  
Very High

Abstract A short pulse of laser light can act as a source of acoustic energy for acoustic imaging. Although there are a number of mechanisms by which the light pulse may generate sound, all require a pulse of high peak power density and short duration. In this work, we address examples where the material is highly absorbing at the laser wavelength, and the sound is generated near the surface. In these cases, there exist two different mechanisms which can convert the light to sound. The first is heating followed by expansion, and the second is generation of a plasma in the air above the surface. In the first case, sound generation occurs in the medium of interest and the energy efficiency can be very high, in the sense that no reflection losses occur. We present two applications from our own research.

Light-Induced Changes in the Subgap Absorption of a-SiC:H

1989 ◽  
Vol 149 ◽  
Author(s):  
M. S. Bennett ◽  
S. Wiedeman ◽  
K. Rajan
Keyword(s):  
Absorption Spectra ◽  
Soaking Time ◽  
Induced Changes ◽  
Sic Films

ABSTRACTThe changes in the absorption spectra of a-SiC films of varying bandgap were monitored as a function of light-soaking time. It was found that the greatest change in absorption occurred at an energy which was 0.55eV less than the energy of the bandgap. It is demonstrated that this could result from a band of states which remain fixed in energy with respect to one of the band edges as the bandgap changes.

Multi-Photon Ionization of Excited Atoms in Gaseous Discharge by Ruby Laser Light

1982 ◽  
Vol 51 (11) ◽  
pp. 3660-3665
Author(s):  
Toshihiko Ohno ◽  
Koichi Suzumura ◽  
Takayoshi Okuda
Keyword(s):  
Ruby Laser ◽  
Laser Light ◽  
Gaseous Discharge ◽  
Excited Atoms ◽  
Photon Ionization

Electron avalanche breakdown induced by ruby laser light

1973 ◽  
Vol 22 (5) ◽  
pp. 206-208 ◽  
Author(s):  
David W. Fradin ◽  
Michael Bass
Keyword(s):  
Ruby Laser ◽  
Laser Light ◽  
Avalanche Breakdown ◽  
Electron Avalanche

scholarly journals Measurements of Photo-Induced Changes in Conjugated Polymers

1991 ◽  
Vol 228 ◽  
Author(s):  
Carleton H. Seager ◽  
Michael B. Sinclair ◽  
D. Mc Branch ◽  
A. J. Heeger ◽  
G. L. Baker
Keyword(s):  
Absorption Spectra ◽  
Light Transmission ◽  
Pump Light ◽  
General Shape ◽  
Experimental Conditions ◽  
Photothermal Deflection Spectroscopy ◽  
Highly Sensitive ◽  
Infra Red ◽  
Transmission Measurements ◽  
Induced Changes

ABSTRACTWe have used the highly sensitive technique of Photothermal Deflection Spectroscopy (PDS) to measure changes in the infra-red absorption spectra of MEHPPV, P3HT and Polydiacetylene-4BCMU induced by pumping these polymers with light above the π - π* transition energy. In contrast to previous chopped light transmission measurements of these effects, the PDS technique can directly measure the buildup or decay of the absorption coefficient, m, on the time scale of seconds to days. In the case of MEHPPV we observe that above-gap light causes the appearance of a broad infra-red peak in α, which continues to grow-in hours after the pump light is first applied. For this polymer the general shape of the absorption spectra in the unpumped state mimics the photo-induced changes, suggesting that remnant photo-induced states determine the maximum transparency observed under normal experimental conditions. For P3HT and to a lesser extent, MEHPPV, we also observe irreversible photo-induced absorption components which we tentatively identify with photo-induced oxidation of the polymer matrix.

scholarly journals PROFIL GELATINISASI DAN KOMPONEN ANTIOKSIDAN TEPUNG KETAN HITAM TERMODIFIKASI DENGAN ANNEALING

2020 ◽  
Vol 31 (2) ◽  
pp. 164-170
Author(s):  
Riezka Zuhriatika Rasyda ◽  
◽  
Tjahja Muhandri ◽  
Slamet Budijanto ◽  
Keyword(s):  
Rice Flour ◽  
Temperature Treatment ◽  
Total Phenolic ◽  
Heating Process ◽  
Composite Flour ◽  
Peak Time ◽  
Annealing Conditions ◽  
Glutinous Rice ◽  
Total Anthocyanins ◽  
Heating Duration

This research aims to study and characterize the effect of the annealing conditions (temperature and heating duration) on the gelatinization profile and antioxidant components of annealing-modified black glutinous rice flour (ABGRF). This experiment used a 2x3 factorial design consisted of temperature factor (54 and 58°C) and heating duration factor (4, 5, and 6 hours) with 2 replications. Research results showed that both factors and their interactions significantly affected all parameters of the gelatinization profile and antioxidant component of ABGRF (except through viscosity). Compared to its native, ABGRF showed an increase in peak viscosity, through viscosity (except treatment 54°C:5 hours), peak time and pasting tem-perature, indicated ABGRF resistance improvement to the heating process. Generally, the temperature treatment increment increased breakdown, setback, and final viscosity, but the heating duration increment decreased those values. The variation of ABGRF gelatinization profiles increased the diversification potential of BGRF-based food products. Annealing caused an overall decrease in ABGRF antioxidant ability. ABGRF produced by 54°C:4 hours treatment had the highest amount of antioxidant components (total anthocyanins contents 103.78±2.24 mg C3GE/100 g, total phenolic compounds 241.65±1.98 mg GAE/100 g, DPPH 267.14± 3.23 mg AAE/100 g, FRAP 473.94±1.43 mg AAE/100 g), thus using it as ingredients in functional food is more recommended, especially as composite flour for bread and cake.

scholarly journals Development of beef volatile flavor compounds in response to varied oven temperature and degree of doneness

2021 ◽  
Author(s):  
Sayani Mallick ◽  
Dale R Woerner ◽  
Talita de Mancilha Franco ◽  
Mark Miller ◽  
Jerrad F. Legako
Keyword(s):  
Surface Layers ◽  
General Increase ◽  
Flavor Compound ◽  
Lipid Degradation ◽  
Volatile Flavor Compounds ◽  
Volatile Flavor Compound ◽  
Volatile Flavor ◽  
Main Effect ◽  
Beef Steaks ◽  
Different Depths

Beef volatile flavor compound (VFC)development at the center, mid, and surface layers of cooked steaks wasevaluated through eighteen cookery treatment combinations consisting of oven cookingtemperature (OT; 177°C, 246°C, and 343°C) and final internal steak temperature(IT; 57°C, 63°C, 68°C, 74°C, 79°C, 85°C). In total, seventy-two VFC were measuredrepresenting the Maillard reaction and lipid degradation. Five VFC wereimpacted by a three-way interaction of OT × IT × layer (P ≤ 0.030). TwoVFC were impacted by a two-way interaction OT × IT (P ≤ 0.010). SixteenVFC were impacted by a two-way interaction OT × layer (P ≤ 0.050). SixteenVFC were impacted by a two-way interaction IT × layer (P ≤ 0.050).Twenty VFC were impacted by main effect of layer (P ≤ 0.010). Eight VFCwere impacted by main effect of IT (P ≤ 0.050). Maillard compounds were formedprimarily at steak surfaces with a general increase in content with greater finalIT and OT to a lesser extent. Lipid derived compounds were diverse. Methyl estersand aldehydes were consistently in lower content at steak surfaces and primarilyfound within the inner portions of steaks. Conversely, certain alcohols and ketoneswere more prominent at steak surfaces. Development of compounds among layers wasalso consistently influenced by IT and OT. It may be concluded that flavor contributingcompounds vary among cooked beef steaks at different depths and cookery temperatures,such as OT and final IT, may be utilized to mediate the final volatile compoundcomposition. 

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