NEW EMISSION BANDS OF ,

1961 ◽  
Vol 39 (8) ◽  
pp. 1138-1145 ◽  
Author(s):  
Y. Tanaka ◽  
T. Namioka ◽  
A. S. Jursa
Keyword(s):  
Transition Formula ◽  
Condensed Discharge

Thirty-eight new bands of nitrogen were observed in the region 2050–3070 Å in an a-c. condensed discharge of neon mixed with a small amount of nitrogen. It was determined that these bands result from the transition [Formula: see text] of [Formula: see text].

Scheelite (CaWO4)-type microphosphors: Facile synthesis, structural characterization and photoluminescence properties

2016 ◽  
Vol 30 (32n33) ◽  
pp. 1650400 ◽  
Author(s):  
Yuanyuan Han ◽  
Dan Wang ◽  
Danyang Liang ◽  
Shiqi Wang ◽  
Guoxin Lu ◽  
...  
Keyword(s):  
Luminescence Decay ◽  
Precipitation Method ◽  
Ammonium Bromide ◽  
Photoluminescence Properties ◽  
Facile Synthesis ◽  
Cetyltrimethyl Ammonium Bromide ◽  
Broad Emission ◽  
Transition Formula ◽  
Cetyltrimethyl Ammonium ◽  
Uv Excitation

Scheelite (CaWO4)-type microphosphors were synthesized by the precipitation method assisted with cetyltrimethyl ammonium bromide (CTAB). All compounds crystallized in the tetragonal structure with space group [Formula: see text] (No. 88). FE-SEM micrographs illustrate the spherical-like morphologies and rough surface. PL spectra indicate the broad emission peak maximum at 613 nm under UV excitation. Luminescence decay curves monitored by [Formula: see text] transition ([Formula: see text] nm) of Eu[Formula: see text] in doped CaWO4 are presented, the curves exhibit a single-exponential feature and the lifetime for doped CaWO4 is 0.61 ms.

scholarly journals The structure of the high pressure carbon bands and the swan system

1929 ◽  
Vol 124 (795) ◽  
pp. 668-688 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
High Pressure ◽  
High Pressures ◽  
Carbon Electrodes ◽  
High Dispersion ◽  
Pressure System ◽  
True Nature ◽  
Discharge Tubes ◽  
Condensed Discharge

The so-called high pressure “ CO ” bands—or high pressure carbon bands, as they are better called—were first found by Fowler* in 1910 in tubes containing carbon monoxide at relatively high pressures. The system was described as consisting of some six apparently double-headed bands degraded to the violet, their wave-lengths being approximately at— 6441 6420 } 5897 5878 } 5431 5413 } 5030 5015 } 4679 4663 } 4365 4353 } Å. U. In 1923 the conditions of production of this spectrum were further investigated by Merton and Johnson who obtained the bands with considerable strength by condensed discharges in capillary tubes fitted with carbon electrodes, and containing CO at pressures of 5 mm. and more. It was found that while the high pressure bands and the Swan bands were mingled in the light from the capillary of the tube, the former bands were isolated in bluish jets where the two ends of the capillary merged into the wider parts of the tube. Further observations indicated that the introduction of a little C0 2 destroyed the bands, but that the system re-apppeared after a few minutes, in which time presumably the carbon dioxide had been reduced to monoxide by the carbon electrodes. A reproduction of these bands photographed under low dispersion is given in the above-mentioned paper. No further experimental work appears to have been done on this system, and it has not been correlated with any other band system or assigned any place in the system of electronic levels of the CO molecule. We have therefore made an attempt to photograph the system under high dispersion with a view to fine structure analysis and identification of the molecular emitter. For this purpose large discharge tubes having a bore of about 15 to 20 mm. and a length of 60 or 70 cm. were used. These had at least one of the electrodes made of carbon and were fitted with side bulbs containing caustic potash and phosphorus pentoxide and a palladium regulator. The tubes were filled with carbon monoxide to such a pressure (probably 20-40 mm.) that a condensed discharge could just be forced through by the ¼ kilowatt 15,000 volt transformer used. Some of the tubes had large side flasks attached to them, increasing thereby the volume of gas in the tube, and giving the tubes a life of 4 to 6 hours during which the high pressure bands were emitted strongly. After some such period the pressure fell below the optimum value, and deposits of carbon had accumulated on the walls of the tube. Impurities such as hydrogen, carbon dioxide, and water-vapour were found to inhibit formation of the high pressure bands, and the tube always attained its best condition after running for about an hour (removing meanwhile any little hydrogen present through the regulator). Under these conditions the wide bore is practically filled with light, and presents a remarkable appearance, as of dense pale blue puffs of smoke (showing the high pressure system), threaded by a narrow green ribbon (showing the Swan system). If side tubes having a fair capacity ( e . g ., flasks) are attached to the discharge tube the high pressure glow is capable of diffusion into these. The appearance is suggestive of an afterglow emitter, but if this is its true nature it is of very short duration. Photographs of the H. P. bands were taken in times varying from 4 to 10 hours in the first order of a 21-foot grating. The green band in the neighbourhood of λ 5000 is exceedingly faint and was not attempted. Before considering the results -obtained it will be an advantage to summarise our present knowledge of the Swan spectrum and its emitter, with which it will subsequently be shown that the high pressure carbon system is intimately related.

Thioamide spectroscopy: long path length absorption and quantum chemical studies of thioformamide vapour, CHSNH2/CHSND2

1987 ◽  
Vol 65 (9) ◽  
pp. 2100-2105 ◽  
Author(s):  
R. H. Judge ◽  
D. C. Moule ◽  
J. D. Goddard
Keyword(s):  
Path Length ◽  
Lower State ◽  
Amino Groups ◽  
Vibrational Assignments ◽  
Transition Formula ◽  
Out Of Plane ◽  
Chemical Studies ◽  
Moderate Resolution ◽  
Quantum Chemical Studies ◽  
Franck Condon

The 270 nm absorption spectra of thioformamide, CHSNH2 and CHSND2, have been photographically recorded under conditions of long path length (88 m) and moderate resolution (7.5 Å/mm). The absorption was assigned to the electron promotion, nS → π* (CS), and to the electronic transition, [Formula: see text]. The spectra proved to be complex, highly congested and somewhat diffuse which limited the extent of the vibrational assignments. Progressions in five members were observed in both CHSNH2/CHSND2 in intervals of 516/496 cm−1 which were assigned to ν10, the out-of-plane aldehyde wagging mode. It was concluded on Franck–Condon grounds that the [Formula: see text] molecule was non-planar at the aldehyde center. Structures and vibrational frequencies were calculated for the [Formula: see text] and the[Formula: see text] electronic states at the 3-21G* SCF level. The calculations confirmed that the lower state was strictly planar and predicted that both the aldehyde and amino groups were pyramidal in the upper electronic state.

scholarly journals New atomic data for the transition Formula in Fe XVIII

1987 ◽  
Vol 225 (2) ◽  
pp. 377-380 ◽  
Author(s):  
M. Mohan ◽  
K. L. Baluja ◽  
A. Hibbert ◽  
K. A. Berrington
Keyword(s):  
Atomic Data ◽  
Transition Formula

scholarly journals Effect of Sr2TiMnO6 fillers on mechanical, dielectric and thermal behaviour of PMMA polymer

2015 ◽  
Vol 05 (03) ◽  
pp. 1550018 ◽  
Author(s):  
P. Thomas ◽  
B. S. Dakshayini ◽  
H. S. Kushwaha ◽  
Rahul Vaish
Keyword(s):  
Coefficient Of Thermal Expansion ◽  
Thermo Gravimetric Analysis ◽  
Mechanical Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Transition Formula ◽  
Thermal Stability Of ◽  
Pmma Polymer

Composites of poly(methyl methacrylate) (PMMA) and [Formula: see text] (STMO) were fabricated via melt mixing followed by hot pressing technique. These were characterized using X-ray diffraction (XRD), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), thermo mechanical analysis (TMA) and impedance analyser for their structural, thermal and dielectric properties. The coefficient of thermal expansion (CTE) was measured between 40°C and 100°C for pure PMMA is 115.2 ppm/°C, which was decreased to 78.58 ppm/°C when the STMO content was increased to 50 wt.% in PMMA. There was no difference in the glass transition ([Formula: see text]) temperature of the PMMA polymer and their composites. However, the FTIR analysis indicated possible interaction between the PMMA and STMO. The density and the hardness were increased as the STMO content increased in the PMMA matrix. Permittivity was found to be as high as 30.9 at 100 Hz for the PMMA+STMO-50 wt.% composites, indicating the possibility of using these materials for capacitor applications. The thermal stability of polymer was enhanced by incorporation of STMO fillers.

scholarly journals SU(3) Polyakov linear-sigma model: Conductivity and viscous properties of QCD matter in thermal medium

2016 ◽  
Vol 31 (34) ◽  
pp. 1650175 ◽  
Author(s):  
Abdel Nasser Tawfik ◽  
Abdel Magied Diab ◽  
M. T. Hussein
Keyword(s):  
Lattice Qcd ◽  
Mean Field ◽  
Field Approximation ◽  
Linear Sigma Model ◽  
Dense Medium ◽  
Mean Field Approximation ◽  
Chiral Phase ◽  
Strange Quarks ◽  
Transition Formula ◽  
Thermal Medium

In mean field approximation, the grand canonical potential of SU(3) Polyakov linear-[Formula: see text] model (PLSM) is analyzed for chiral phase transition, [Formula: see text] and [Formula: see text] and for deconfinement order-parameters, [Formula: see text] and [Formula: see text] of light- and strange-quarks, respectively. Various PLSM parameters are determined from the assumption of global minimization of the real part of the potential. Then, we have calculated the subtracted condensates [Formula: see text]. All these results are compared with recent lattice QCD simulations. Accordingly, essential PLSM parameters are determined. The modeling of the relaxation time is utilized in estimating the conductivity properties of the QCD matter in thermal medium, namely electric [Formula: see text] and heat [Formula: see text] conductivities. We found that the PLSM results on the electric conductivity and on the specific heat agree well with the available lattice QCD calculations. Also, we have calculated bulk and shear viscosities normalized to the thermal entropy, [Formula: see text] and [Formula: see text], respectively, and compared them with recent lattice QCD. Predictions for [Formula: see text] and [Formula: see text] are introduced. We conclude that our results on various transport properties show some essential ingredients, that these properties likely come up with, in studying QCD matter in thermal and dense medium.

scholarly journals Note on the oxygen afterglow

1935 ◽  
Vol 150 (869) ◽  
pp. 34-36 ◽  
Keyword(s):  
Electrodeless Discharge ◽  
Condensed Discharge

A paper on the oxygen afterglow by Stoddart appears in ‘Proc. Roy. Soc.,’ A, December 1, 1931. Many years ago I made an investigation on this subject. The title was perhaps not sufficiently explicit, and the paper escaped Stoddart’s notice. The conclusions reached are not in agreement with his, and I wish to draw attention to the old experiments, which appeared to me at the time, and appear still, to be definite and conclusive, as far as they go. Stoddart’s experiments seem to have been carefully carried out. But rather different experiments would, I believe, have led to a different conclusion. Before coming to the main point, it is necessary to deal with one preliminary matter. That is the meaning to be attached to the expression “Electrodeless discharge.” The phrase has usually been applied to the bright discharges obtained by J. J. Thomson, by electromagnetic induction, using the currents induced by a coil of wire wrapped round the tube, through which is passed the oscillatory discharge of a condenser. Dis­charges of this kind approximate to the condensed discharge in an electrode tube.

scholarly journals Spark spectra of bismuth, Bi II and Bi III. Evidence of hyperfine structure

1930 ◽  
Vol 129 (811) ◽  
pp. 579-588 ◽  
Keyword(s):  
Hyperfine Structure ◽  
Term Structure ◽  
Optical System ◽  
Spectral Region ◽  
Considerable Progress ◽  
Condensed Discharge ◽  
Made In

Wave-lengths in the spectrum of a condensed discharge in heated bismuth vapour have been measured from λ 7050 A. to λ 2000 A. and those in the spectrum of a condensed spark between metallic terminals in hydrogen from λ 2000 A. to λ 1340 A. Hilger E 1 spectrographs, one with a glass and one with a quartz optical system, were used to study the first-mentioned spectral region and a Hilger vacuum fluorite instrument for the latter range. Light from a hot spark between metallic terminals in vacuo was photographed with a 1-metre vacuum grating spectrograph in order to investigate the spectrum below λ 1340 A. By a study of the frequencies of the wave-lengths thus obtained, considerable progress has been made in the identification of the multiplet term structure of bismuth II and of bismuth III. Confirmation of the correctness of assignment of wave-lengths to one or other of these spectra was obtained readily in most cases by varying the excitation of the sources of light by means of inductance in the secondary spark circuit.

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