scholarly journals On Cluster Calculation for Amorphous Tetrahedrally Bonded Semiconductors

1997 ◽  
Vol 20 (1) ◽  
pp. 1-5
Author(s):  
M. A. Grado-Caffaro ◽  
M. Grado-Caffaro
Keyword(s):  
Electronic Spectra ◽  
Amorphous Semiconductors ◽  
The Other ◽  
Cluster Calculation ◽  
Other Hand ◽  
Valence States ◽  
Theoretical Considerations ◽  
Operational Methods ◽  
Tetrahedrally Bonded

This article consists of an approach to the calculation of the density of valence states in tetrahedrally bonded amorphous semiconductors and, on the other hand, the paper contains theoretical considerations on electronic spectra related to the results obtained by the authors concerning cluster calculation. The exposition is centered on III–V compounds. Moreover, operational methods are used to perform certain computations related to the previous subjects.

scholarly journals Determination of the Ratios of Ligands to Metal Ion of some Metal Complexes of Triazoles by Using Eleetronie Speetra in Organie Solvents

2004 ◽  
Vol 1 (1) ◽  
pp. 110-115
Author(s):  
Baghdad Science Journal
Keyword(s):  
Solid State ◽  
Metal Complexes ◽  
Electronic Spectra ◽  
Metal Ion ◽  
The Other ◽  
Molar Ratio ◽  
Other Hand

We found that 4,5- diphenyl- 3(2- propynyl) thio- 1??-triazole [1? forms a complex with Pd (11) ion of ratio 1:1 which absorbs light in CH2CI2 at 400 nm, and 4,5- diphenyl- 3(2- propenyl) thio- 1,2,4- triazole [II] forms complexes with Pd (II) ion of ratio 1:1 which absorbs light at 390 nm, and of ratio 2:1 which absorbs light at 435 nm. On the other hand, we found that the new derivative 4- phenyl- 5( p- amino phenyl) -3- mercapto- 1,2,4- triazole ?111? forms complexes with Cu (II) ion of the ratio 1:1 which absorbs light at 380 nm, with Ni (II) ion of the ratio 3:1 which absorbs light at 358 nm; and with Co (11) ion of the ratio 3.2:1 which absorbs light at 588 nm. The ratio of the complexes were determined by measuring the electronic spectra of the complexes in CH2G2 and (CH^NCHO at different concentrations ofthe ligands and f?xed ' •' of the metal ion in every case, then applying the molar ratio plots on the data. Our results were confirmed by precipitating most ofthe above complexes in solid state, and then each complex was analyzed elementally.

Experimental Determination of the Cinematic Misfit within the Transmission of a 4x4 Vehicle that Leads to Self-Generated Torque along the Vehicle’s Inter-Axle Driveline

2014 ◽  
Vol 659 ◽  
pp. 262-267
Author(s):  
Marian Truta ◽  
Marin Marinescu ◽  
Octavian Alexa ◽  
Radu Vilau ◽  
Valentin Vinturis
Keyword(s):  
Experimental Determination ◽  
Experimental Methods ◽  
The Self ◽  
The Other ◽  
Other Hand ◽  
Theoretical Considerations ◽  
The Way

Present paper aims at revealing a way to determine the cinematic misfit within a 4x4 vehicle’s inter-axle driveline, which is eventually the reason of the self-generated torque occurrence. We used experimental methods to determine the magnitude of the cinematic misfit. Within this frame, we used a vehicle that has a longitudinal (inter-axle) differential and we locked it, actually forcing the longitudinal transmission to work without differentiating the angular speeds on its output shafts. On the other hand, the tire radii were different, inducing the above-mentioned cinematic misfit that we were looking for. We also present the way we fit the transducers on the vehicle’s driveline components to measure the needed parameters. The paper also presents some theoretical considerations regarding the occurrence of the cinematic misfit and its way of generating closed power loops within the vehicle’s transmission.

Practical Seismology and Seismic Prospecting. L. D. Leet. D. Appleton‐Century Company, New York, 1938. x+430 pp. $6.00. (The Century Earth Science Series, Kirtley F. Mather, Editor.)

Geophysics ◽  
1938 ◽  
Vol 3 (4) ◽  
pp. 358-358
Author(s):  
M. M. Slotnick
Keyword(s):  
New York ◽  
Wave Propagation ◽  
Earth Science ◽  
The Other ◽  
Elastic Theory ◽  
Seismic Prospecting ◽  
Other Hand ◽  
Instrumental Technique ◽  
Theoretical Considerations

To most people interested in seismic prospecting, the title of the volume will perhaps be somewhat misleading. A large part of the book is devoted to earthquake lore in general; and those early chapters devoted to the geology of this subject, the reviewer found intensely interesting. On the other hand, the treatment on seismic prospecting, as the term is generally understood, is rather inadequate. One feels that the author might have done far more with the various theoretical considerations of instrumental technique, elastic theory, wave‐propagation and such. The treatment, mathematical and physical, cannot be considered convincing—in fact this writer feels that it is definitely superficial in most places.

scholarly journals A New Mathematical Model for Cluster Calculation in Tetrahedrally Bonded Amorphous Semiconductors

1993 ◽  
Vol 16 (1) ◽  
pp. 49-53 ◽  
Author(s):  
M. A. Grado Caffaro ◽  
M. Grado Caffaro
Keyword(s):  
Mathematical Model ◽  
Amorphous Semiconductors ◽  
Sufficient Accuracy ◽  
Cluster Calculation ◽  
X Rays ◽  
Electronic Density ◽  
Valence States ◽  
Hückel Theory ◽  
Theoretical Results ◽  
Good Agreement

Tetrahedraily bonded amorphous semiconductors exhibit a structure suitable for applying the so-called extended Hückel theory (EHT) to determine the electronic density of states by means of the cluster calculation. In the following, a new mathematical model based on EHT is established. The results obtained from this model have sufficient accuracy for applications and provide a useful methodology that combines adequately with the spectrum computations. Density of valence states has been obtained experimentally with monochromatized X-rays and the theoretical results obtained in this paper are in good agreement with these experiments.

scholarly journals Influence of Different Sieving Methods on Estimation of Sand Size Parameters

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 879 ◽  
Author(s):  
Poullet ◽  
Muñoz-Perez ◽  
Poortvliet ◽  
Mera ◽  
Contreras ◽  
...  
Keyword(s):  
Standard Deviation ◽  
The Other ◽  
Coastal Dynamics ◽  
Other Hand ◽  
Mechanical Shaker ◽  
Operational Methods ◽  
Skewness And Kurtosis ◽  
Sand Size

Sieving is one of the most used operational methods to determine sand size parameters which are essential to analyze coastal dynamics. However, the influence of hand versus mechanical shaking methods has not yet been studied. Herein, samples were taken from inside the hopper of a trailing suction dredger and sieved by hand with sieves of 10 and 20 cm diameters on board the dredger. Afterwards, these same samples were sieved with a mechanical shaker in the laboratory on land. The results showed differences for the main size parameters D50, standard deviation, skewness, and kurtosis. Amongst the main results, it should be noted that the highest values for D50 and kurtosis were given by the small sieves method. On the other hand, the lowest values were given by the mechanical shaker method in the laboratory. Furthermore, standard deviation and skewness did not seem to be affected by the sieving method which means that all the grainsize distribution was shifted but the shape remained unchanged. The few samples that do not follow these patterns have a higher percentage of shells. Finally and definitely, the small sieves should be rejected as a sieving method aboard.

The electronic spectra and magnetic behaviour of some dithiocacodylate complexes

1971 ◽  
Vol 24 (8) ◽  
pp. 1587 ◽  
Author(s):  
AT Casey ◽  
DJ Mackey ◽  
RL Martin
Keyword(s):  
Field Strength ◽  
Electronic Spectrum ◽  
Electronic Spectra ◽  
Magnetic Behaviour ◽  
The Other ◽  
Ligand Field ◽  
Ionic Character ◽  
Nephelauxetic Effect ◽  
Other Hand ◽  
Square Planar

The large nephelauxetic effect and low ligand field strength produced by the dithiocacodylate group [(CH3)2AsS2-] in complexes with Ni2+, Co2+, and Cr3+ is explained in terms of significant covalency of the metal- sulphur bonds. The Mn2+ compound, however, has properties consistent with considerable ionic character. ��� The electronic spectrum and magnetic behaviour of bisdithiocacodylato-cobalt(II) can be better interpreted in terms of tetrahedral rather than octahedral CoSx microsymmetry. On the other hand, the Ni2+ compound is square-planar and both the Mn2+ and Cr3+ compounds appear to be octahedrally coordinated by sulphur atoms.

scholarly journals X. On the mineral constituents of meteorites

1870 ◽  
Vol 160 ◽  
pp. 189-214 ◽  
Keyword(s):  
Chemical Separation ◽  
The Other ◽  
Fine Grained ◽  
Other Hand ◽  
Mineralogical Investigation ◽  
The One ◽  
Theoretical Considerations ◽  
Mineral Constituents ◽  
Insoluble Portion

I. The applications of the Microscope in the investigation of Meteorites . The mineralogical investigation of a meteoric stone presents difficulties very similar to those which have hitherto rendered the analyses and descriptions of many of the finer-grained terrestrial rocks unsatisfactory ; for a meteoric stone is in fact a fragment of a rock, though formed under conditions in some respects widely differing from those which have produced the rocks of our globe. The difficulties alluded to arise from the minute size and imperfectly developed crys­tallisation of the mineral constituents alike of the rock and the aërolite ; and they have in general baffled the efforts of the chemist on the one hand to effect their separate analyses, and of the crystallographer on the other hand to determine the forms of these constituents. The chemist indeed has endeavoured to overcome the difficulty by attempt­ing a chemical separation of the constituent minerals of these fine-grained mixtures into one group of such as are soluble and another group of those which are insoluble in acids, and then treating the numbers obtained from the analyses of these groups by the light of theoretical considerations founded on the formulae and properties of known minerals. This method is necessarily only an approximative one. Even granting that by its means, we could divide a rock into two classes of ingredients, which we cannot in fact accurately do, there remains the question of how to separate from each other the mingled minerals in, for instance, its insoluble portion.

scholarly journals Log Files as a Tool for Improving Internet Dictionaries

2017 ◽  
Vol 18 (34) ◽  
pp. 117
Author(s):  
Henning Bergenholtz ◽  
Mia Johnsen
Keyword(s):  
Empirical Research ◽  
The Other ◽  
User Behaviour ◽  
Log Files ◽  
Other Hand ◽  
Types Of Information ◽  
Dictionary Use ◽  
Theoretical Considerations

In their advertisements, dictionary publishers often praise their dictionaries for taking into account the exact needs of the users. Until the beginning of the 1980s, however, no theoretical contributions on dictionary use were available, neither in the form of purely theoretical considerations nor in the form of empirical research. Since then, the situation has changed completely. Such a large number of user surveys have been carried out that it is no longer possible to give a complete overview. Nevertheless, this has led to no significant improvement of the situation as the majority of these surveys are not related to concrete examples of dictionary use. The surveys, which have always been concerned with printed dictionaries, have therefore not contributed to substantial improvements of dictionary conception. In the case of internet dictionaries, on the other hand, technical possibilities enable lexicographers to monitor user behaviour in a different and much more precise way. Analyses of log files reveal exactly which lemmas and which types of information have been requested, and, perhaps more significantly, which lemmas and which types of information have been requested but were not found in the dictionary. Furthermore, log files allow lexicographers to see the types of information which have not, or not yet, been searched for. All in all, log files may thus be used as a tool for improving internet dictionaries – and perhaps also printed dictionaries – quite considerably.

THE CYTOLOGY OF THREE HYBRIDS INVOLVING HORDEUM JUBATUM L.: THE CHIASMA DISTRIBUTIONS AND THE OCCURRENCE OF PSEUDO RING-BIVALENTS IN GENETICALLY INDUCED ASYNAPSIS

1960 ◽  
Vol 38 (1) ◽  
pp. 69-85 ◽  
Author(s):  
E. B. Wagenaar
Keyword(s):  
Secale Cereale ◽  
The Other ◽  
Random Pattern ◽  
Secondary Effect ◽  
Chiasma Distribution ◽  
Other Hand ◽  
Ring Bivalents ◽  
Secale Cereale L ◽  
Hordeum Jubatum ◽  
Theoretical Considerations

Three hybrids, two of Hordeum jubatum L. × Secale cereale L. var. Prolific, and one of H. jubatum × H. bulbosum L., were examined cytologically. The two genomes of H. jubatum showed autosyndesis in the H. jubatum × S. cereale hybrids. It was concluded, therefore, that H. jubatum has two closely related genomes.One of the H. jubatum × S. cereale hybrids displayed weak asynapsis. The H. jubatum × H. bulbosum hybrid, on the other hand, showed strong asynapsis, although the prophase pairing was almost complete. It was concluded that the asynapsis of this latter hybrid was due to interaction of genes of the H. jubatum and the H. bulbosum genomes.The chiasma distributions of the hybrids were tested for randomness by Gaul's formula. It was found that the chiasma distributions of the H. jubatum × S. cereale hybrids followed a random pattern, whereas in the H. jubatum × H. bulbosum hybrid the distribution was disturbed by a secondary effect. Cytological observations and theoretical considerations led to the conclusion that the occurrence of pseudo ring-bivalents had disturbed the apparent chiasma distribution in the H. jubatum × H. bulbosum hybrid. A theory of the origin of pseudo bivalents and an evaluation of Gaul's formula is presented.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

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