scholarly journals Study the Effect of solvent on the Optical Properties Performance of active polymeric laser media

2007 ◽  
Vol 4 (3) ◽  
pp. 387-392
Author(s):  
Baghdad Science Journal
Keyword(s):  
Absorption Spectrum ◽  
Pure Water ◽  
Wave Length ◽  
Blue Shift ◽  
Short Wave ◽  
Fluorescence Yield ◽  
Effect Of Solvent ◽  
Long Wave ◽  
Short Wave Length ◽  
Laser Media

The paper include studies the effect of solvent of dye doped in polymeric laser sample which manufactured in primo press way, which is used as an active (R6G) tunable dye lasers. The remarks show that, when the viscosity of the solvent (from Pure Water to Ethanol), for the same concentration and thickness of the performance polymeric sample is increased, the absorption spectrum is shifts towards the long wave length (red shift), & towards short wave length (blue shift) for fluorescence spectrum, also increased the quantum fluorescence yield. The best result we obtained for the quantum fluorescence yield is (0.882) with thickness (0.25mm) in Ethanol solvent in concentration (2*10-3mole/liter), while when we used the Pure Water as a solvent, we found that the best quantum fluorescence yield is (0.72) at the same thickness & concentration of the sample.

scholarly journals On the absorption of light by crystals

1938 ◽  
Vol 167 (930) ◽  
pp. 384-391 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Wave Length ◽  
Short Wave ◽  
Point Of View ◽  
Theoretical Point ◽  
Lattice Vibrations ◽  
Short Wave Length ◽  
Continuous Absorption ◽  
Absorption Of Light ◽  
Positive Hole

The purpose of this paper is to discuss the absorption of light by non-metallic solids, and in particular the mechanism by which the energy of the light absorbed is converted into heat. If one considers from the theoretical point of view the absorption spectrum of an insulation crystal, one finds that it consists of a series of sharp lines leading up to a series limit, to the short wave-length side of which true continuous absorption sets in (Peierls 1932; Mott 1938). In practice the lattice vibrations will broaden the lines to a greater of less extent. When a quantum of radiation is absorbed in the region of true continuous absorption, a free electron in the conduction band and a "positive hole" are formed with enough energy to move away from one another and to take part in a photocurrent within the crystal. When, however, a quantum is absorbed in one of the absorption lines , the positive hole and electron formed do not have enough energy to separate, but move in one another's field in a quantized state. An electron in a crystal moving in the field of a positive hole has been termed by Frenkel (1936) an "exciton".

Short and Long Wave Peristaltic Flow: Modeling and Mathematical Analysis

2015 ◽  
Vol 07 (01) ◽  
pp. 1550014 ◽  
Author(s):  
Lorenzo Fusi ◽  
Angiolo Farina ◽  
Antonio Fasano
Keyword(s):  
Mathematical Model ◽  
Wave Length ◽  
Oscillation Amplitude ◽  
Short Wave ◽  
Peristaltic Flow ◽  
Flow Modeling ◽  
Small Aspect Ratio ◽  
Long Wave ◽  
Short Wave Length ◽  
Axisymmetric Channel

In this paper, we present a mathematical model for the peristaltic flow of a Newtonian fluid in an axisymmetric channel with small aspect ratio. In particular, we study the effects of the wave length of the wall oscillation distinguishing between long wave length (same order of the vessel's length) and short wave length (same order of the vessel's radius). We prove that the oscillation produces flow even in the absence of a pressure gradient in case of long wave. In case of short wave length, peristalsis does not affect the flow. We also prove that, in both cases, the tube resistance increases as the oscillation amplitude increases.

scholarly journals Absorption of lithium vapour

1924 ◽  
Vol 106 (735) ◽  
pp. 51-54 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Alkali Metals ◽  
Wave Length ◽  
Visible Region ◽  
Principal Series ◽  
Short Wave ◽  
Ultraviolet Region ◽  
Large Radius ◽  
Short Wave Length

The fluorescence and channelled absorption spectra of the vapours of the alkali metals have been studied by several physicists, notable among them being Roscoe and Schuster, Liveing and Dewar, Wood and his collaborators, Bevan, and Dunoyer, Wood, working with a concave grating of large radius showed that there are as many as 8,000 absorption lines in the visible region of the absorption spectrum of sodium. In a recent paper Prof. McLennan and Ainslie have given an account of some interesting experiments on the subject, where cesium has been shown for the first time to possess a channelled absorption spectrum in the neighbourhood, and on the short wave-length side, of the first member of the principal series, and a fluorescence spectrum in the near infra-red region. Though attempts were made by these authors to get spectrograms of fluorescence and channelled absorption with the vapour of lithium, no definite results could be obtained, but they pointed out that their preliminary results indicated that lithium possessed a banded absorption spectrum in the ultraviolet region between 0.4 μ and 0.3 μ The failure to obtain channelled absorption spectrum with lithium vapour was probably due to their not obtaining vapour of sufficient density, as the boiling point of the metal is of the order of 1,400°C. In this investigation there were found with lithium vapour not only channelled absorption spectra, both on the short and the long wave-length side of the first line of the principal series, but also, as in the case of sodium, it has been found that there is a fine line absorption spectrum immediately on each side of the main line.

scholarly journals QUANTUM RELATIONS IN PHOTOREACTIVATION OF COLPIDIUM

1953 ◽  
Vol 37 (2) ◽  
pp. 249-258 ◽  
Author(s):  
A. C. Giese ◽  
R. M. Iverson ◽  
D. C. Shepard ◽  
C. Jacobson ◽  
C. L. Brandt
Keyword(s):  
Visible Light ◽  
Wave Length ◽  
Red Light ◽  
Lethal Dose ◽  
Short Wave ◽  
Single Quantum ◽  
Injurious Effect ◽  
Long Wave ◽  
Short Wave Length ◽  
Incident Quantum

1. The amount of visible or long ultraviolet light (UV) required to photoreactivate Colpidium colpoda injured with known dosages of short UV (2654 A) was determined. 2. The effect of the short UV was tested by the delay in division of exposed animals compared to controls. Photoreactivation was tested by the effect of postillumination on the delay of division of treated colpidia compared to controls. 3. Colpidia were used in two physiological states: well fed and starved in balanced medium for 48 hours. The latter are much more sensitive to short UV although less susceptible of photoreactivation. 4. Photoreactivation occurred over the entire span from 3350 A to 4350 A for the well fed colpidia, from 3130 A to 5490 (green) for starved colpidia. 5. The photoreactivating effect of a single quantum of blue (4350 A) or long UV (3660 A) delivered per quantum of 2654 A used to injure colpidia was too slight to be considered significant. The effect of 10 quanta was usually more pronounced, but only after 100 quanta had been delivered was the photoreactivation nearly maximal for well fed colpidia. 6. The quantum requirement for maximal photoreactivation of the starved animals was greater at all wave lengths tried: 3660, 4050, 4350, and 5460 A being of the order of 800 incident quanta per incident quantum of 2654 A. 7. The transmission of UV(2654 A), blue, yellow, and red light by a suspension of colpidia was determined. 8. Large dosages of blue, violet, or long UV were slightly injurious to starved colpidia. In a few cases large dosages of 3660 A killed starved colpidia, especially after a non-lethal dose of short UV(2654 A). 9. Photoreactivation seems to be a balance between the slight injurious effect produced by the visible light or UV of long wave lengths and the injury produced by short wave length UV. 10. Possible reasons for the large number of quanta of photoreactivating light required per quantum of short UV are discussed.

scholarly journals The Bakerian lecture —Regularities and irregularities in the ionosphere—I

1937 ◽  
Vol 162 (911) ◽  
pp. 451-479 ◽  
Keyword(s):  
Specific Conductivity ◽  
Wave Length ◽  
Ground Level ◽  
Short Wave ◽  
The State ◽  
Total Conductivity ◽  
The Sun ◽  
Magnetic Studies ◽  
Short Wave Length ◽  
Radio Measurements

Our knowledge concerning the state of the atmosphere lying above about 80 km. in height has been derived from experiments on radio wave reflexion as well as from studies of terrestrial magnetism and of the aurora. The information derived from radio experiments is, fortunately, in the nature of a supplement to, rather than a duplicate of, information derivable in other ways. As one of the best examples in this connexion may be mentioned the question of electrical conductivity. Here the magnetic studies of Schuster and Chapman yield an estimate of the total conductivity for currents travelling horizontally, whereas the radio measurements give the state of ionization at different levels from which the specific conductivity at those levels may be estimated. One of the most striking things about the ionosphere is the marked solar control. Speaking generally it may be said that the ionization increases and decreases as the sun rises and sets. Again, speaking generally, we may say that the main part of the ionization is caused by solar-violet light. The rays from the sun meet the outer layers of the atmosphere first and the short wave-length radiation is absorbed there, causing ionization. It thus comes about that the study of the ionosphere becomes the study of an interesting part of the sun's spectrum which cannot be detected at ground level. It also becomes the study of certain atomic processes such as photo-ionization, recombination of ions and attachment of electrons to neutral molecules such as cannot be investigated at very low pressure in the laboratory, because of the influence of the walls of the vessel confining the gas.

The Results of Astroclimate Observations in the Short-Wave Length Interval of the Millimeter-Wave Range on the Suffa Plateau

2017 ◽  
Vol 59 (8-9) ◽  
pp. 763-771 ◽  
Author(s):  
G. M. Bubnov ◽  
Yu. N. Artemenko ◽  
V. F. Vdovin ◽  
D. B. Danilevsky ◽  
I. I. Zinchenko ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
Wave Length ◽  
Short Wave ◽  
Short Wave Length ◽  
Millimeter Wave Range ◽  
Wave Range

Die Beeinflussung der Zellkerne in den Vorkeimen von Dryopteris filix-mas durch rote und blaue Strahlung

1963 ◽  
Vol 18 (7) ◽  
pp. 557-562 ◽  
Author(s):  
Rainer Bergfeld
Keyword(s):  
Protein Synthesis ◽  
Visible Light ◽  
Blue Light ◽  
External Factor ◽  
Wave Length ◽  
Red Light ◽  
Three Dimensional ◽  
Short Wave ◽  
Nuclear Volume ◽  
Short Wave Length

Morphogenesis and differentiation of fern gametophytes (Dryopteris filix-mas) are strongly controlled by light. “Normal” morphogenesis, i. e. formation of two- or three dimensional prothallia, can occur only under short wave length visible light (= blue light). In darkness and under long wave length visible light (= red light) the gametophytes will grow as filaments. The blue light dependent photoreactive system which controls morphogenesis seems to be located in the outer layers of the cytoplasm. The control of morphogenesis is causally connected with the increase of protein synthesis under the influence of blue light.In the present paper the influence of red and blue light on shape and volume of the nucleus in the fully grown basal cell of the young gametophyte of Dryopteris filix-mas has been investigated. In blue light the nuclei are more or less spherical, in red and in darkness they are spindle shaped. If the light quality is changed the shape of the nuclei is only slightly influenced; the nuclear volume, however, is drastically changed: increase of volume in the blue, decrease of nuclear volume in red and darkness. These reversible changes of nuclear volume under the influence of light, which are apparently correlated with changing rates of protein synthesis, are an impressive example for the control of nuclear properties by an external factor via the cytoplasm.

scholarly journals Control of Short-Wave Length Irregularity of Slivers

1960 ◽  
Vol 6 (1) ◽  
pp. 31-34
Author(s):  
Shoichi Ishikawa ◽  
Jiro Shimizu
Keyword(s):  
Wave Length ◽  
Short Wave ◽  
Short Wave Length
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