Showing papers by "Islamic Azad University published in 1997"

The Triassic and associated rocks of the Nakhlak and Aghdarband areas in central and northeastern Iran as remnants of the southern Turanian active continental margin

Abstract: The Triassic succession of the Nakhlak area in central Iran consists of (1) the LithologicallAlam Formation, which is a sequence of shallowing- and coarsening-upward marine turbidites deposited equon the forearc side of an accretionary prism; (2) the Baqoroq Formation, a resentatsequence of coarse to fine, polymictic, fluvial conglomerates; and (3) the Ashin For- mation, which comprises alternating, distal marine shales and sand- stones that have turbiditic characteristics. These rocks are wnot litholog- ically similar to time-equivalent lithostratigraphic units of Late Permian – Triassic age of the Aghdarband area of northeastern Iran (which are interpreted to be forearc deposits), but they may have formed in close association with them in a single tectonic and sedimen- tary framework. Accepting the 135° counterclockwise rotation of the central-east Iranian microcontinent authorwith respect to the Turan plate since Triassic time, and assuming that the Triassic rocks of the Nakhlak and the Late Permian to Triassic rocks of the Aghdarband formed in a single tectonosedimentary framework on the no rthern side of the paleo-Tethyan oceanic realm, we present here a sequential develop- ment. In this scheme, rocks of the bNakhlak and Aghdarband areas are considered deposits of a forearc, basin-ridge-slope centralenvironment. The separation of the Nakhlak succession from the rest of the Turan plate and its transportation to central Iran might have occurred as (1) a lithospheric segmen t of the Turan plate, first detached from Turan and then attached to the Iranian plate, and finally rotated with it in a coun- terclockwise direction to successionits present site; or (2) as a thin thrust slice first obducted over th e Iranian continental shelf and then displaced to cen- tral Iran by its counterclockwise rotation. INTRODUCTION

Composition of the essential oil of Salvia sahendica Boiss. and Buhse

Abstract: The essential oil of the aerial parts of Salvia sahendica Boiss. et Buhse. has been analyzed by a combination of GC and GC/MS. Among the 24 components identified in this oil, α-pinene (29.4%) and β-pinene (34.8%) were found to be the major constituents.

Essential oil of salvia hydrangea dc. ec benth

Abstract: The composition of the essential oil of Salvia hydrangea DC. ex Benth. was analyzed by GC and GC/MS. The major constituents were spathulenol (23.1%), 1,8-cineole (12.3%), α-pinene (10.04%) and β-caryophyllene (99%).

Continuous speech recognition and syntactic processing in Iranian Farsi language

Abstract: In this paper, the architecture of the first Iranian Farsi continuous speech recognizer and syntactic processor is introduced. In this system, by extracting suitable features of speech signal (cepstral, delta-cepstral, energy and zero-crossing rate) and using a hydrid architecture of neural networks (a Self-Organizing Feature Map, SOFM, at the first stage and a Multi-Layer Perceptron, MLP, at the second stage) the Iranian Farsi phonemes are recognized. Then the string of phonemes are corrected, segmented and converted to formal text by using a non-stochastic method. For syntactic processing, the symbolic (by using artificial intelligence techniques) and connectionist (by using artificial neural networks) approaches are used to determine the correctness, position and the kind of syntactic errors in Iranian Farsi sentences, as well.

Semiempirical SCF MO study of bowl-to-bowl inversion in corannulene and smaller circulenes

Abstract: The results of MINDO/3, MNDO, AM1, and PM3 semi-empirical SCF MO calculations for angle deformation and resonance stabilization effects in corannulene (1) indicate that for molecules in which the strain arises primarily from angle bendings, MNDO provides more reliable results. Both MINDO/3 and MNDO underestimate bowl-to-bowl inversion barrier in 1 by 2.7 and 2.3 kcal mol−1, respectively; PM3 and AM1 exaggerate this barrier by 5.5 and 6.6 kcal mol−1, respectively. Structural features and dynamic behaviour of smaller circulenes, compounds with a circular arrangement of four and three benzene rings, are also reported.

Chromatographic separation of inorganic ions on thin layers of lanthanum silicate ion-exchanger

Abstract: Thin layers of lanthanum silicate have been used to study the chromatographic behaviour of 28 metal ions in aqueous and mixed systems. As3+, Mo6+, Sb3+, Ti4+ and others can be easily separated from a number of inorganic ions. Fast ternary and binary separations have also been achieved and various separations are discussed. It is shown that Alberti's relation is also obeyed by thin layers of lanthanum silicate.

Reaction between trimethyl phosphite and dimethyl acetylenedicarboxylate in the presence of 5,5-dimethylcyclohexane-1,3-dione

Abstract: Proton, carbon-13, and phosphorus-31 NMR spectroscopy and AM1 SCF MO calculations have been employed to investigate the molecular structure of the demethylated protonated adduct obtained from 1:1:1 addition reaction of the title compounds.

AM1 study of conformational and configurational energy surfaces of 1,6-, 1,4-, and 3,4-diazacyclonona-1,2,4,5-tetraene

Abstract: An investigation employing the AM1 semiempirical SCF MO method to calculate structure optimization, conformational and configurational interconversion pathways for the two diastereoisomeric forms of 3,4-, 1,6-, and 1,4-diazacyclonona-1,2,4,5-tetraene ( 1–3 ) has been undertaken. For compound 1 , the meso -diastereoisomer is calculated to be 12.8 kJ mol −1 more stable than the ( ± )-isomer. The chair conformation of meso - 1 is 5.3 kJ mol −1 more stable than the boat form. The ground-state conformation of ( ± )- 1 , is the axial symmetrical twist-boat conformation which is 4.9 kJ mol −1 more stable than the unsymmetrical twist form. Interconversion of the two diastereoisomeric forms of 1 via CC or CN bond rotation or nitrogen atom inversion is calculated to require more than 200 kJ mol −1 . The meso -isomer of 2 is calculated to be 10 kJ mol −1 more stable than the ( ± )-isomer. Configurational interconversion between the meso - and ( ± )-diastereoisomers of 2 requires about 60 kJ mol −1 . The chair conformation of meso - 2 is calculated to be 5.9 kJ mol −1 less stable than the boat conformation. The chair and the boat conformations of meso -like- 3 have similar energies. The meso -like diastereoisomer of 3 is calculated to be 11 kJ mol −1 more stable than the ( ± )-isomer. Configurational interconversion of the two diastereoisomers of 3 can take place by nitrogen inversion and requires about 66 kJ mol −1 .

MNDO Study of Nitrogen Atom Inversion in Piperazine, N,N'-Dimethylpiperazine and N,N'-Dichloropiperazine

Abstract: MNDO semi-empirical SCF MO calculations are used to study the pyramidal nitrogen atom inversion and configurational equilibria in the title compounds.

Hyper bck-algebr

Abstract: In this note the notion of a hyper BCK-algebra which is a generalization of a BCK-algebra introduced, and some basic properties for this algebra are proved. Then the notions of P-ideals and hyper-congruence relations are introduced, and the relationship between them on a positive implicative hyper Bek-algebra with condition (8), are spec-ified.

Application of neural networks to the segmentation of MRI: comparison of different networks

Abstract: In this paper a comparative study of the application of four neural networks (NN) for the segmentation of magneticresonance images (MRI) of brain, is proposed. The segmentation of MRJ images enable one to present tissues of the samecategory with an equal gray level (or color) resulting in a more clear image for future diagnosis and treatments. Results ofusing three supervised networks, i.e. multi-layered perceptron (MLP), probabilistic neural network (PNN) and radial basisfunctions (RBF) and one unsupervised network, i.e. adaptive resonance theory 2 (ART2) will be reported.Keywords: Segmentation, MRJ, Neural networks, Multi-layered perceptron, Probabilistic neural network,Radial basis functions, Adaptive resonance theory 2

Design and Fabrication of DC Ion Beam for Heating of Plasma

Abstract: DC type ion beam is produced by using different percentages of argon gas content. In this manner, about 90% of argon gas was ionized, and the ion beam diameter is controllable by the extractor in 10−3torr. The density of charged particles was measured by Faraday cup. In this paper, some recent findings are presented dealing with the analysis of the production of ion beam with different energy levels. Result of measurements compare with that of other sources.

Ionic strength dependence of stability constant. Part 2: Spectrophotometric study of the dioxyvanadium+leucine system in the range 0.1⩽1⩽1.0

Abstract: The dioxyvanadium+leucine system has been investigated by a combination of spectrophotometric and potentiometric methods at 25±0.1°C and ionic strengths ranging from 0.1 to 1.0 mol dm−3 with NaClO4 as a background salt in thepH range 1.3–2.5, with high ligand-to-metal ratios. Parameters for dependence on ionic strength have been obtained for the protonation constant of leucine.