نشریه علوم دانشگاه خوارزمی
سال چهاردهم شماره 3 (پاییز 1393)

In the present study، we investigate DC conduction mechanism of electron beam evaporated Bromoaluminium phthalocyanine (BrAlPc) thin films using aluminum and gold electrodes. The current-voltage characteristics of sandwich type device are evaluated for the temperature range 298-413K under dark conditions. It is observed that the current passing through the device is increased by increasing temperature at the same voltage in the range of 0-6v. It is found that at lower voltages about 0 to 2v، the current–voltage characteristics demonstrate Ohmic behavior، while the space charge limited current (SCLC) becomes apparent at higher voltages about 2 to 6v، which is restricted by single discrete trapping level. We obtained more than one linear region in the temperature dependence of electrical conductivity. Also، the values of charge carrier mobility and the activation energy of device are evaluated.

The aim of this study was to estimate Specific Absorption Rate (SAR) induced in human head tissues، by assuming human head as a cubical model filled with lossy dielectric material and exposed to electromagnetic plane waves. The research is carried out by computational simulation using C programming codes. The numerical technique used in this study was Finite Difference in Time Domain (FDTD) method، along with Perfectly Matched Layer (PML) as an appropriate absorbing boundary condition. Different conditions including exposure conditions as well as physical parameters are employed، in order to compare the results to the past literature. Finally، the penetration depth of one of the specified models is expressed by means of interpolation. The results which are in complete agreement with the others in some cases، suggests that considering the biological tissues as dispersive media، would result in correct estimations; whereas changing in the structure of the model، doesn’t differ if precise predictions are not important. Furthermore، the penetration depth correlation to frequency is in line with what is expressed in theoretical papers.

The concept of rotundity is not far from differentiability. Some paper investigate the relation between rotundity and smoothness. In this paper we will explain some new relation between rotundity and very smoothness. A Banach space is rotund if the midpoint of every two distinct points of unit sphere is in the open unit ball of Banach space. A Banach space is smooth if its norm is Gateaux differentiable at every non zero point of the space and it is very smooth if the norm is very Gateaux differentiable. That is، the norm of Banach space and the norm of second dual of Banach space are Gateaux differentiable at every non zero point of Banach space.

In this paper rationalized Haar (RH) functions method is applied to approximate the numerical solution of the fractional Volterra integro-differential equations (FVIDEs). The fractional derivatives are described in Caputo sense. The properties of RH functions are presented، and the operational matrix of the fractional integration together with the product operational matrix are used to reduce the computation of FVIDEs into a system of algebraic equations. By using this technique for solving FVIDEs time and computational are small. Numerical examples are given to demonstrate application of the presented method with RH functions base. In this paper rationalized Haar (RH) functions method is applied to approximate the numerical solution of the fractional Volterra integro-differential equations (FVIDEs). The fractional derivatives are described in Caputo sense. The properties of RH functions are presented، and the operational matrix of the fractional integration together with the product operational matrix are used to reduce the computation of FVIDEs into a system of algebraic equations. By using this technique for solving FVIDEs time and computational are small. Numerical examples are given to demonstrate application of the presented method with RH functions base.

The methanol extracts of leaves and bulbs of Allium ampeloprasum L. (Alliaceae) were analyzed for their phenolic profiles and screened for their antioxidant and antibacterial activities. Two biochemical assays، namely DPPH free radical scavenging and β-caroten/linoleic acid activity systems، were used to evaluate antioxidant activity. Total phenol and flavonoid contents of the species were determined by Folin-Ciocalteu and AlCl3 assays، respectively. Results indicated that the extracts are different in total phenolic content. Results from antioxidant activity showed that the extracts studied in DPPH radical scavenging assay are lower active than ascorbic acid and BHT as synthetic antioxidants. Antibacterial assay showed that the bulbs extract is more effective in inactivation of Haemophilus influenzae and Bacillus cereus and the leaves extract is more effective in inactivation of Bacillus cereus at 100 mg ml-1 than others. Then، the extracts of Allium ampeloprasum possess strong antioxidant activity and may be used as new drug supplements in the future.

Genus Cerastium belongs to the subfamily Alsinoideae. This genus is represented with about 30 species in two subgenera (subgenus Dichodon and subgenus Cerastium) and three sections (sect. Strephodon، sect. Orthodon and sect. Schizodon) in flora Iranica area، of which 19 species were reported from Iran. The materials in the TARI herbarium were studied. The vegetative and reproductive characteristics of specimens were checked by stereomicroscope. In family Caryophyllaceae، the seeds bear numerous characters which can be used for taxonomic purposes. The ornamentation features of the seed surface and its relief are different from one species to another. The seeds were carefully taken from mature and dehiscent capsules. Pollen grains obtained from flowers bearing mature anthers. In this paper، Cerastium pentandrum (Caryophyllaceae) is reported as a new record from northwest Iran and Iranian plateau. It belongs to the subg. Cerastium sect. Orthodon. In this section teeth of the capsule are elongated، straight or reflexed، with flat or recurved margins. Morphological characteristics of the new record are provided. This taxon is compared with its closest relative C. balearicum. The ultrastructure of seed and pollen is examined by SEM.

Periwinkle (Catharanthusroseus L.) is one of the most important medicinal plants that commonly used for its anticancer alkaloids. In this investigation، the effects of different tryptophan concentrations (0، 150، 250 and 350 mg/l) under in vitro regeneration conditions have been studied. The regeneration of different explants on different media compositions in free tryptophan condition showed that the best media conditions obtained by nodal segments explants grown on MS medium containing (BAP، 0. 5 mg/l) + (NAA، 1 mg/l). Also، we achieved the rooting medial composition as half MS medium supplemented with (IBA، 0. 1 mg/l). After adding of tryptophan into this optimal medium، the maximum shooting and rooting percentages were obtained in the media containing 250 and 350 mg/l tryptophan، respectively. Furthermore، the measurement of shoot and root length، dry and fresh weight of shoot، fresh weight of root، chlorophyll a and carotenoid content and also، soluble sugars content of shoot and root، revealed the best medium in the presence of 350 mg/l tryptophan، while the maximum amount of root dry weight and chlorophyll b were obtained by 250/l mg tryptophan containing medium.. Finally، the analysis of total proteins content of shoot and root showed significant difference between all groups and the higher content of this for shoots and roots observed in 250 mg/l and 350 mg/l، respectively.