JOURNAL OF SCIENCES (ISLAMIC AZAD UNIVERSITY)
Year:2001 | Volume:11 | Issue:41|Papers Count:11

Calix [4] arenes, bis - crown - 6 (BC6) and bis - crown - 5 (BC5) being in 1, 3 alternate conformation are able to complex Lanthanum ions in methanol. The stability constant measurements using UV\Vis. Spectroscopy and fitting of the data reveal a 1:1 (metal/ligand) ratio for the complexes formed for both systems. BC5 present a higher efficiency than BC6, as the date reported for the crown ethers 15C5/18C6 and B15C5/DB18C6 in literature.

LaNiO3 Compound with perovskite structure was synthesized by different methods and effect of synthesis conditions on crystal structure was studied. X-ray diffraction and elemental analysis were used for characterization of synthesized samples. The morphology of synthesized crystals was studid by SEM method. The surface areas of the compound was measured by BET method.

In this research aqueous solution equilibria of the system. "VO+2+ glycylglycine" have been studied by combination of spectrophotometric methods (UV-Vis), in the pH ranges 1.5 to 7.5 with high ligand to metal ratio. The ionic strength was maintained at 0.5 mol dm-3 with sodium perchlorate. The thermodynamic values were calculated from the variation of Ki with temperature. The protonation constants of glycylglycine kH1 and kH2 were also determined potentiometrically under the same condition. Furthermore the thermodynamic values of protonation of glycylglycine were estimated by the variation of K as a function of temperature.

In this research, the ability of Cyanobacteria "Nostoc sp"; in relation to adaptation with flactuations of salinity levels were investigated. Specimens were collected from paddy fields of Gorgan, and after purification were treated with 0;0.5; and 1% NaCl salinities; pH 5, 7, 9 and air CO2 condition, (with and without vanadate). Results showed that this species can grow successfuly in 0.5%; and 1.0% salinites. The effect of 0.5% salinity on heterocyst frequency were noticable. There were not seen a recovery stage in 0.5% salinity. The causes of the excretion of phycobilliproteins were discussed. Growth and heterocyst prodnction completely blocked in pH5. Growth curve in pH 9 and also results of treating vanadate in air CO2 condition; show possible function of bicarbonate concentrating mechanism in this species.

Phenytione is one of the untiepilepsy drug and the microbicid effect of this drug observed. In this work, micvobicide effects of this drug as in vitro studied. The plate method was used, since the solubility of phenytoine is low. The obtained results showed the phenytoine is not affect on the 104, 106, and 108 concentration (microbe per ml) of the many of the microbes. Consequently, it can concluded that the phenytoine undirectly affect on the wound as a microbicide drug.

During upper pliocene and pliestocene a non-marine succession (Akchagyl and Apsheron formation respectively), about 485 m thick, was deposited in Moghan basin, NW of Iran. Both formations begin with fluvial conglomerate and ultimately with lacustrine deposits. Mud is the main constituent of this succession. XRD and XRF analyses have been carried out on mudstones from f1uvial to lacustrine deposits. The clay minerals identified were beidellite, illite-smectite mixed-layer, illite, chlorite and kaolinite. Apart from clay minerals, calcite, quartz, feldspar, volcanic ash and heulandite were recognized. Heulandite is of diagenetic origin and some calcites were authigene. The other components were detrital and derived from the out of basin and surrounding lands. X -ray diffractmeters show no changes in volcanic ashes composition. These amorphous materials were made of opal and/or opal, quartz, feldspat and mica. Clay minerals in fluvial and lacustrine systems had no obvious differences. In the other word new clay minerals had not been formed in lacustrine system. Variations of the amounts and proportions of the clay minerals were related to paleoclimatic changes. Based on the former findings and the unchanged volcanic ashes in the muds. The paleosalinity of Akchagyl and Apsheron basins must have been fresh or brackish.

The governing equation of multi-link robots are nonlinear in nature. Perturbation analesis is used to arrive at approximate closed form solutions to better understand the behaviour of these system at resonance, when flexible link and a flexible joint to stady the effects of nonlinearities. MAPLE is used in this study to arrive at the approximate solution of the equation of motion of the robot in question the two variable are expanded in a power series and the terms of this series are solved recursively. The study reveals that the system behaves like one with quadratic nonlinearities, and periodicts, saturation at internal resonance and the jump resonance phenomenon.

High quality of commercial and research uses of acoustical methods in fisheries needs to have enough information about sound speed variations, Ray tracing and attenuation rate in the water. In this paper we focused on the sound speed variations versus depth for physical properties of Bandar Dayer (NE of Farsi island and about 50 kilometers south of Delwar, 282 N and 5058 E) and calculation of attenuation rate. Importance of this area is for the Gulf Currents, Which cover this region. The results of this research show that up to 11 meters of depth sound speed remains constant while depth increases and temperature decreases. After this depth, sound speed decreases which is a result of decreasing in slinity. Sound attenuation profiles show that the most attenuation rate is at 17-27 meters depth.

In this paper numerical thms for solving”fuzzy ordinary differential equations” are considered. A scheme based on the Runge-Kutta method of order two is discussed in detail and this is followed by a complete error analysis. The algorithm is illustrated by solving some linear and nonlinear fuzzy Cauchy problems.

discontinuities with 1 km or greater lengths and bends with 5° or greater angles are chosen. Based on these limits, seven segments and associated earthquakes (with magnitudes equal or greater than 5.0) are recognized. From this data set it appears that fault geometry, such as bends and stepovers along the main fault trace, plays an important role in controlling the location of moderate to large earthquakes along the fault zones. Certain geometrinc patterns, such as restraining stepovers, are particularly common and can be viewed as responsible for strain accumulation along portions of fault zone. Moderate to large earthquake epicenters often occur near restraining stepovers.