Influence of radiation intensity on the value of the mean quantum yield of the photodestruction of benzophenone

1981 ◽  
Vol 34 (2) ◽  
pp. 235-237
Author(s):  
K. M. Dyumaev ◽  
E. P. Lebedeva ◽  
G. A. Matyushin
Keyword(s):  
Quantum Yield ◽  
Radiation Intensity ◽  
The Mean

Der Einfluß der Bandbreite des Anregungslichtes bei der Bestimmung von Quantenausbeuten photochemischer Reaktionen / The Influence of the Bandwidth of the Exciting Light in Determining the Quantum Yields of Photochemical Reactions

1979 ◽  
Vol 34 (11) ◽  
pp. 1344-1351
Author(s):  
R. Schöneich ◽  
J. Bendig ◽  
D. Kreysig
Keyword(s):  
Quantum Yield ◽  
Radiation Intensity ◽  
Photochemical Reactions ◽  
Wave Number ◽  
Quantum Yields ◽  
Exciting Light ◽  
Considerable Influence ◽  
Interference Filters

Monochromatic excitation is one of the experimental requirements for determining quantum yields of photochemical reactions. It can, however, be strictly satisfied only in certain conditions. The photoisomerization of E,E-1,4-diphenylbutadiene-(1,3) is taken as an example for studying the effect of the bandwidth of the exciting light by using interference filters. The bandwidth is shown to have a considerable influence on the experimentally determined value of the partial quantum yield. Identical results are obtained when making allowance for the wave number dependence on radiation intensity and the absorption of the reactant compounds

scholarly journals Bactericidal effects of the partial irradiation of a room with ultra-violet light

1946 ◽  
Vol 44 (5) ◽  
pp. 333-341 ◽  
Author(s):  
O. M. Lidwell
Keyword(s):  
Point Source ◽  
Radiation Intensity ◽  
Ultra Violet ◽  
Small Particles ◽  
Ultra Violet Light ◽  
Short Series ◽  
Violet Light ◽  
Constant Rate ◽  
Bactericidal Effects ◽  
The Mean

The process of removal of bacteria from the air of a room of which part only is irradiated with ultra-violet light is discussed.Formulae are derived for the rate of disappearance of bacteria from the air in such circumstances and for The equilibrium levels reached when bacteria-carrying particles are being continuously introduced into the air at a constant rate. These formulae include terms for the effect of simultaneous ventilation and for the effect of sedimentation of the bacteria-carrying particles.The results of a short series of tests are compared with those calculated from these formulae and the two found to agree reasonably well on the assumption that the air within both the irradiated and nonirradiated zones is effectively mixed.Figures are given over a range of humidities for the sensitivity of salivary organisms to ultra-violet irradiation when suspended as small particles in the air.A chart is presented for the evaluation of the mean radiation intensity within a rectangular volume produced by a point source situated within or on the boundaries of the volume.

Comparison of ultraviolet (UV) radiation intensity between a single lamp and a double lamp in a reactors

2014 ◽  
Vol 9 (4) ◽  
pp. 558-565
Author(s):  
Gholamreza Asadollahfardi ◽  
Matin Molaei ◽  
Masoud Taheriyoun ◽  
Ivan Leversage
Keyword(s):  
Drinking Water ◽  
Energy Distribution ◽  
Radiation Intensity ◽  
Pathogenic Bacteria ◽  
Emission Rate ◽  
Chemical Compounds ◽  
Uv Reactor ◽  
Volume Emission ◽  
The Mean ◽  
Better Than

Disinfection of drinking water is a challenging and controversial issue. Chemical and ultraviolet (UV) methods are used to deactivate bacteria. Some of the chemical disinfection causes threats to public health since they produce toxic chemical compounds. Recently, several researchers conducted experiments and mathematical models to deactivate pathogenic bacteria from wastewater and drinking water using UV. The intensity of UV is very effective in deactivating bacteria. The authors compared the radiation intensity of a single and double lamp in a UV reactor for water treatment using computational fluid dynamics. The results indicated that the mean volume emission rate of single lamp and double lamp in the reactor was similar. However, the energy distribution of single lamps was much better than the double lamp in the reactor. The sensitivity analysis using three different UV transmittances (UVT), 70, 80 and 90%, indicated that the increase in % UVT value improved the energy distribution in the UV reactor.

Substituted Derivatives of 10-Phenyl-9-Acetoxyanthracene. Absorption and emission spectra, quantum yield and lifetime of fluorescence

1975 ◽  
Vol 30 (5) ◽  
pp. 612-618 ◽  
Author(s):  
Janina Heidt ◽  
Józef Heidt ◽  
Janina Gronowska
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Fluorescence Spectra ◽  
Emission Spectra ◽  
Oscillator Strengths ◽  
Steric Effects ◽  
Absorption And Fluorescence Spectra ◽  
Mean Lifetime ◽  
The Mean ◽  
Derivatives Of

Abstract Absorption The absorption and fluorescence spectra of five substituted derivatives of 10-phenyl-9-acetoxy-anthracene were measured and the oscillator strengths of the 1A→1La1A→1Bb and 1A→1Cb electronic vibration bands were determined. Comparison of the absorption spectra of these compounds to the unsubstituted molecule (anthracene) indicate the presence of bathochromic and steric effects. The fluorescence quantum yield and the mean lifetime of the fluorescence were also measured.

scholarly journals The Globe Thermometer in Studies of Heating and Ventilation

1934 ◽  
Vol 34 (4) ◽  
pp. 458-473 ◽  
Author(s):  
T. Bedford ◽  
C. G. Warner
Keyword(s):  
Air Temperature ◽  
Radiation Intensity ◽  
Thermal Environment ◽  
Average Error ◽  
Equivalent Temperature ◽  
Air Velocity ◽  
Mean Error ◽  
The Mean ◽  
Effects Of Radiation

The effects of radiation and convection on the globe thermometer have been studied.Equations have been obtained, and alignment charts constructed, for the calculation of mean radiation intensity and of equivalent temperature from readings of the globe thermometer, air temperature and air velocity.The accuracy of these methods has been tested on observations made under industrial conditions. Taking direct thermopile observations as the standard, the mean radiation intensity values calculated from globe thermometer readings had an average error of 1·2 B.Th.U. per sq. ft. per hour. With eupatheoscope readings as standard, equivalent temperature estimates had a mean error of 1·2°.It is concluded that, while globe thermometer readings alone are unreliable as indications of the effects of the thermal environment, valuable results can be obtained by using the instrument along with an ordinary thermometer and a silvered kata-thermometer.

scholarly journals Statistical treatment of Photoluminescence Quantum Yield Measurements

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Felix Fries ◽  
Sebastian Reineke
Keyword(s):  
Quantum Yield ◽  
Statistical Treatment ◽  
Systematic Errors ◽  
Statistical Uncertainty ◽  
Photoluminescence Quantum Yield ◽  
Multiple Measurements ◽  
The Mean ◽  
The Impact ◽  
Random Uncertainties

Abstract The photoluminescence quantum yield (PLQY) is an important measure of luminescent materials. Referring to the number of emitted photons per absorbed photons, it is an essential parameter that allows for primary classification of materials and further is a quantity that is of utmost importance for many detailed analyses of luminescent systems and processes. Determining the PLQY has been discussed in literature for many years and various methods are known. Absolute values can be measured directly using an appropriate setup. As this relies on the correct evaluation of photon-counts, it is a very sensitive method. Hence, systematic errors that can occur are discussed widely. However, of course those measurements also contain random uncertainties, which remain mainly unconsidered. The careful evaluation of both systematic and statistical errors of the PLQY is the only way to gain confidence in its absolute value. Here, we propose a way of evaluating the statistical uncertainty in absolute PLQY measurements. This relies on the combination of multiple measurements and the subsequent calculus of the weighted mean. The statistical uncertainty is then obtained as the standard deviation of the mean. This method not only quantifies the impact of statistical influences on the measurements, but also allows simple analysis of time-dependent systematic errors during the measurement and the identification of outliers.

Photo-electric Hβ and uvby photometry

1966 ◽  
Vol 24 ◽  
pp. 170-180
Author(s):  
D. L. Crawford
Keyword(s):  
Narrow Band ◽  
Line Strength ◽  
Interference Filter ◽  
B Stars ◽  
Relative Line ◽  
The Mean ◽  
F Stars ◽  
Two Parameters ◽  
Filter Photometry ◽  
The Continuum

Early in the 1950's Strömgren (1, 2, 3, 4, 5) introduced medium to narrow-band interference filter photometry at the McDonald Observatory. He used six interference filters to obtain two parameters of astrophysical interest. These parameters he calledlandc, for line and continuum hydrogen absorption. The first measured empirically the absorption line strength of Hβby means of a filter of half width 35Å centered on Hβand compared to the mean of two filters situated in the continuum near Hβ. The second index measured empirically the Balmer discontinuity by means of a filter situated below the Balmer discontinuity and two above it. He showed that these two indices could accurately predict the spectral type and luminosity of both B stars and A and F stars. He later derived (6) an indexmfrom the same filters. This index was a measure of the relative line blanketing near 4100Å compared to two filters above 4500Å. These three indices confirmed earlier work by many people, including Lindblad and Becker. References to this earlier work and to the systems discussed today can be found in Strömgren's article inBasic Astronomical Data(7).

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

The motion of a lunar orbiter

1966 ◽  
Vol 25 ◽  
pp. 373
Author(s):  
Y. Kozai
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Artificial Satellite ◽  
Equations Of Motion ◽  
Triaxial Ellipsoid ◽  
The Moon ◽  
Secular Motion ◽  
The Earth ◽  
Close Satellite ◽  
The Mean

The motion of an artificial satellite around the Moon is much more complicated than that around the Earth, since the shape of the Moon is a triaxial ellipsoid and the effect of the Earth on the motion is very important even for a very close satellite.The differential equations of motion of the satellite are written in canonical form of three degrees of freedom with time depending Hamiltonian. By eliminating short-periodic terms depending on the mean longitude of the satellite and by assuming that the Earth is moving on the lunar equator, however, the equations are reduced to those of two degrees of freedom with an energy integral.Since the mean motion of the Earth around the Moon is more rapid than the secular motion of the argument of pericentre of the satellite by a factor of one order, the terms depending on the longitude of the Earth can be eliminated, and the degree of freedom is reduced to one.Then the motion can be discussed by drawing equi-energy curves in two-dimensional space. According to these figures satellites with high inclination have large possibilities of falling down to the lunar surface even if the initial eccentricities are very small.The principal properties of the motion are not changed even if plausible values ofJ3andJ4of the Moon are included.This paper has been published in Publ. astr. Soc.Japan15, 301, 1963.

On nearly-commensurable periods in the restricted problem of three bodies, with calculations of the long-period variations in the interior 2:1 case

1966 ◽  
Vol 25 ◽  
pp. 197-222 ◽  
Author(s):  
P. J. Message
Keyword(s):  
Periodic Solution ◽  
Periodic Solutions ◽  
Large Amplitude ◽  
Restricted Problem ◽  
Small Amplitude ◽  
Minor Planets ◽  
Long Period ◽  
Numerical Integrations ◽  
Period Variations ◽  
The Mean

An analytical discussion of that case of motion in the restricted problem, in which the mean motions of the infinitesimal, and smaller-massed, bodies about the larger one are nearly in the ratio of two small integers displays the existence of a series of periodic solutions which, for commensurabilities of the typep+ 1:p, includes solutions of Poincaré'sdeuxième sortewhen the commensurability is very close, and of thepremière sortewhen it is less close. A linear treatment of the long-period variations of the elements, valid for motions in which the elements remain close to a particular periodic solution of this type, shows the continuity of near-commensurable motion with other motion, and some of the properties of long-period librations of small amplitude.To extend the investigation to other types of motion near commensurability, numerical integrations of the equations for the long-period variations of the elements were carried out for the 2:1 interior case (of which the planet 108 “Hecuba” is an example) to survey those motions in which the eccentricity takes values less than 0·1. An investigation of the effect of the large amplitude perturbations near commensurability on a distribution of minor planets, which is originally uniform over mean motion, shows a “draining off” effect from the vicinity of exact commensurability of a magnitude large enough to account for the observed gap in the distribution at the 2:1 commensurability.

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