Journal of Sciences, Islamic Republic of Iran
Year:2008 | Volume:19 | Issue:2|Papers Count:10

The five-toed jerboas of genus Allactaga Cuvier, 1837 have been distributed in arid and semi-desert regions throughout northern Africa, Iranian Plateau and Central Asia to Mongolia. This genus has 12 species of which five have been so far reported from Iran including, Small Five-toed Jerboa (A. elater), William’s Jerboa (A. williamsi), Euphrate’s Jerboa (A. euphratica); Hotson’s Jerboa (A. hotsoni) and Firouz Jerboa (A. firouzi). The Toussi Jerboa (Allactaga toussi sp. Nov.) is reported for the first time from the steppe regions of north east Iran. This new species is different in external, cranial and molars morphological and morphometric characteristics from its parapatric species i.e. Allactaga elater, and other Iranian five-toed jerboas. Multivariate analyses also confirm that Allactaga toussi sp. nov. is significantly distinct from other species.

The electrochemical coating technique was used for the preparation of a polypyrrole coating on a stainless-steel wire, and applied as a fibre for solid phase microextraction (SPME). The polypyrrole fibre was employed for analyzing four volatile aliphatic amines (ethylamine, propylamine, butylamine and pentylamine) in water by headspace SPME using gas chromatography-flame ionization detection (GC-FID). Results showed that this fibre coating is suitable for the successful extraction of the target analytes. The effects of the extraction parameters including exposure time, sampling temperature, salt concentration, and stirring rate on the extraction efficiency was optimized. Relative standard deviations (RSDs) were determined ≤4.3%. The correlation coefficient was satisfactory (r2 > 0.98) for the studied analytes. Detection limits were between 0.9 and 1.6mg.L-1. Good recoveries (99-106 %) were obtained when spiked water and wastewater samples were analyzed

Carbon nanotubes (CNTs) were prepared by the catalytic chemical vapor deposition of C2H2 at 550oC in 120 minutes using nanoparticles of Ni-Ce-Zr mixed oxides. The CNTs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. The results revealed that CNTs with diameter of about 45 nm are obtained. Utilization of Ni-Ce mixed oxides or NiO2 respectively afforded CNTs with helical and curved morphologies and diameters of about 50 and 90 nm. No CNTs were formed either in the absence of catalyst or exclusion of Ni from Ce-Zr mixed oxides. Details of the catalyst type and its impact on CNTs morphologies will be presented.

The Chah-Bagh gold occurrence is located in Muteh mining district, in the central part of the Sanandaj-Sirjan zone. Gold mineralization occurs in ductile to ductile-brittle shear zones and is comparable with orogenic gold deposits. Silicification and sulfidization are the most important hydrothermal alteration features in the inner parts of altered shear zones and coincide most closely with the ore-bearing zones. Principal ore minerals are pyrite, chalcopyrite, arsenopyrite and native silver. Silver commonly occurs both as native Ag grains (ca. 5mm in diameter) intimately associated with siliceous gangue and as invisible silver within sulfides. The maximum concentration of invisible silver occurs in chalcopyrite. Although native gold was not identified in the siliceous gangue and in the sulfide minerals and their alteration products, electron microprobe analyses confirmed the occurrence of invisible gold within sulfides. Two phases of gold mineralization occurred in the Chah-Bagh area: 1- invisible gold within coarse-grained sulfides (pyrite and chalcopyrite); 2- invisible gold (the main phase) within fine-grained sulfides (pyrite and chalcopyrite). Evidently, the precipitation of gold was an integral part of the hydrothermal alteration system and was associated with sulfide minerals. Although electron microprobe analyses of auriferous sulfide indicated the presence of gold in sufficient quantities to explain the bulk gold concentrations, native gold has not been detected in our polished sections.

Orpiment, getchellite and stibnite from Zarshuran deposit, NW Iran, exhibit extensive As-Sb substitution. There are four known minerals along As2S3-Sb2S3 join, i.e. orpiment (As2S3), Wakabayashilite [(As,Sb)20S30], getchellite (AsSbS3) and stibnite (Sb2S3). Extensive mineralogical studies by scanning electron microscope (SEM) and electron probe micro-analyzer (EPMA) indicate that getchellite from Zarshuran exhibits large As/Sb substitution, compared to the synthetic mineral and occurrences in other deposits, which justifies further experimental studies. Natural orpiment with the highest Sb content was recorded in Zarshuran samples. Considering the possible explanation for the incomplete record of solid solution, it appears that rapid variation in fluid chemistry and variability of As and Sb concentration in the hydrothermal solution may have caused extensive solid solution in the As2S3-Sb2S3 system. The recorded solid solution may indicate that temperatures of gold mineralization were less than 250oC which is supported by fluid inclusion data.

A one-sided ideal I of a ring R has the insertion of factors property (or simply, IFP) if abeI implies raRbÍI for a,beR. We say a one-sided ideal I of R has the weakly IFP if for each a,b,reR,  abeI implies (arb)neI, for some non-negative integer n. We give some examples of ideals which have the weakly IFP but have not the IFP. Connections between ideals of which have the IFP and related ideals of R some ring extensions are also shown.

We define a new function-valued inner product on L2(G), called j-bracket product, where G is a locally compact abelian group and j is a topological isomorphism on G. We investigate the notion of j -orthogonality, Bessel's Inequality and j -orthonormal bases with respect to this inner product on L2(G).

In this paper we define w-independent (a weak-version of independence), Kronecker and dissociate sets on hypergroups and study their properties and relationships among them and some other thin sets such as independent and Sidon sets. These sets have the lacunarity or thinness property and are very useful indeed. For example Varopoulos used the Kronecker sets to prove the Malliavin theorem. In the final section we bring some examples and find w-independent and dissociate sets on a compact countable hypergroup of Dunkle and Ramirez, the dual Chebychev polynomial hypergroup, and some other polynomial hypergroups from Lasser.

The weighted semigroup algebra Mb (S, w) is studied via its identification with Mb (S) together with a weighted algebra product *w so that (Mb (S, w), *) is isometrically isomorphic to (Mb (S), *w). This identification enables us to study the relation between regularity and amenability of Mb (S, w) and Mb (S), and improve some old results from discrete to general case.

In this research we described the effective Hamiltonian theory and applied this theory to the calculation of current-current (Q1,2) and QCD penguin (Q3,…,6) c quark decay rates. We calculated the decay rates of semileptonic and hadronic of charm quark in the effective Hamiltonian theory. We investigated the decay rates of D meson decays according to Spectator Quark Model (SQM) for the calculation of D meson decays. We obtained the total decay rates of semileptonic and hadronic of charm quark in the effective Hamiltonian according to colour Favoured (C-F) and colour Suppressed (C-S). We combined them and to added amplitude of processes colour Favoured and colour Suppressed (F+S) and obtained the decay rates of them.