2020-08-12T00:22:10Z
https://jsciences.ut.ac.ir/?_action=export&rf=summon&issue=4506
Journal of Sciences, Islamic Republic of Iran
J.Sci.I.R.I
1016-1104
1016-1104
2007
18
4
Synthesis of Binary Ti-Si Mixed Oxides Nanoparticles with Rutile Structure as Selective Catalyst for Epoxidation of Alkenes
F.
Farzaneh
The nanoparticles of Ti-Si mixed oxides (NTSO) with Rutile structure were prepared by sol-gel method in a mixture of alcohol and water as solvent. The solid product was characterized by XRD, FTIR, SEM, TEM, UV, TGA and laser Raman spectroscopy. The catalytic activity of NTSO (5-10 nm) was investigated in the epoxidation of cis stilbene, trans stilbene, and norbornene by using oxidants such as tert-butylhydroperoxide (TBHP), molecular oxygen (O<sub>2</sub>)/isobutyraldehyde (IBA) and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>). It was found that epoxides of trans-stilbene andnorbornenewereformedquantitativelywiththegreenH<sub>2</sub>O<sub>2</sub>oxidantduring12h.
Epoxidation
Alkenes
Ti-Si mixed oxides
nanoparticles
Heterogeneous catalysis
2007
12
01
303
395
https://jsciences.ut.ac.ir/article_35065_7dd368e2a660d1b78517bb5587f186ec.pdf
Journal of Sciences, Islamic Republic of Iran
J.Sci.I.R.I
1016-1104
1016-1104
2007
18
4
Complete Convergence and Some Maximal Inequalities for Weighted Sums of Random Variables
M.
Amini
Let be a sequence of arbitrary random variables with and , for every and be an array of real numbers. We will obtain two maximal inequalities for partial sums and weighted sums of random variables and also, we will prove complete convergence for weighted sums , under some conditions on and sequence .
2007
12
01
311
316
https://jsciences.ut.ac.ir/article_35073_d621f17bd3310b1e9969d451974cb757.pdf
Journal of Sciences, Islamic Republic of Iran
J.Sci.I.R.I
1016-1104
1016-1104
2007
18
4
A Computational Meshless Method for Solving Multivariable Integral Equations
E.
Babolian
In this paper we use radial basis functions to solve multivariable integral equations. We use collocation method for implementation. Numerical experiments show the accuracy of the method.
2007
12
01
317
321
https://jsciences.ut.ac.ir/article_35075_efa1cb388921b5a382f132d3c315a55d.pdf
Journal of Sciences, Islamic Republic of Iran
J.Sci.I.R.I
1016-1104
1016-1104
2007
18
4
On the U-WPF Acts over Monoids
A.
Golchin
Valdis Laan in [5] introduced an extension of strong flatness which is called weak pullback flatness. In this paper we introduce a new property of acts over monoids, called<em> U-WPF</em> which is an extension of weak pullback flatness and give a classification of monoids by this property of their acts and also a classification of monoids when this property of acts implies others. We also show that regularity and strong faithfulness of acts both imply <em>U-WPF</em>. An equivalent of that over monoids for which torsion freeness implies <em>U-WPF</em> is given too.
U-WPF
Strongly faithful
Regular
2007
12
01
323
328
https://jsciences.ut.ac.ir/article_35076_7179cbf62319b0387870e23cc9c2338f.pdf
Journal of Sciences, Islamic Republic of Iran
J.Sci.I.R.I
1016-1104
1016-1104
2007
18
4
Nonlinear Two-Phase Stefan Problem
K.
Ivaz
In this paper we consider a nonlinear two-phase Stefan problem in one-dimensional space. The problem is mapped into a nonlinear Volterra integral equation for the free boundary.
Free boundary problems
integral equation
2007
12
01
329
337
https://jsciences.ut.ac.ir/article_35077_32721d24440447cca51b48fcd81190bb.pdf
Journal of Sciences, Islamic Republic of Iran
J.Sci.I.R.I
1016-1104
1016-1104
2007
18
4
Derivations on Certain Semigroup Algebras
M.
Lashkarizadeh Bami
In the present paper we give a partially negative answer to a conjecture of Ghahramani, Runde and Willis. We also discuss the derivation problem for both foundation semigroup algebras and Clifford semigroup algebras. In particular, we prove that if <em>S</em> is a topological Clifford semigroup for which <em>E<sub>s</sub></em> is finite, then <em>H</em><sup>1</sup>(<em>M</em>(<em>S</em>),<em>M</em>(<em>S</em>))={0}.
Foundation semigroup
Semigroup algebra
Derivation
First order cohomology
Clifford semigroup
2007
12
01
339
345
https://jsciences.ut.ac.ir/article_35078_5dc248c0cdd852f58b420f59cb5d150c.pdf
Journal of Sciences, Islamic Republic of Iran
J.Sci.I.R.I
1016-1104
1016-1104
2007
18
4
Modified Progressive Type-II Censoring Procedure in Life-Testing under the Weibull Model
M.
Khodadadi
In this paper we introduce a new scheme of censoring and study it under the Weibull distribution. This scheme is a mixture of progressive Type II censoring and self relocating design which was first introduced by Srivastava [8]. We show the superiority of this censoring scheme (PSRD) relative to the classical schemes with respect to “asymptotic variance”. Comparisons are also made with respect to the total expected time under experiment (TETUE) as an important feature of time and cost saving. These comparisons show that TETUE<sub>(<em>SRD</em>)</sub> < TETUE<sub>(<em>PSRD</em>)</sub> < TETUE<sub>(<em>PC</em>2)</sub> if 0 < <em>β</em> < 1, TETUE<sub>(<em>PSRD</em>)</sub> = TETUE<sub>(<em>SRD</em>)</sub> < TETUE<sub>(<em>PC</em>2)</sub> if <em>β</em> = 1 and TETUE<sub>(<em>PSRD</em>)</sub> is the best among all the designs if <em>β</em> = 2 (Rayleigh distribution case).
Asymptotic variance
Fisher information matrix
Maximum likelihood
Self relocating design (SRD)
Total expected time under experiment
2007
12
01
347
354
https://jsciences.ut.ac.ir/article_35079_97b138e63d61d51fa7c1effe3f11847d.pdf
Journal of Sciences, Islamic Republic of Iran
J.Sci.I.R.I
1016-1104
1016-1104
2007
18
4
Essentially Retractable Modules
M.R.
Vedadi
We call a module <em>essentially retractable </em>if Hom<sub>R</sub> for all essential submodules <em>N</em> of <em>M</em>. For a right FBN ring <em>R</em>, it is shown that: (i) A non-zero module is <em>retractable</em> (in the sense that Hom<sub>R</sub> for all non-zero ) if and only if certain factor modules of <em>M</em> are essentially retractable nonsingular modules over <em>R</em> modulo their annihilators. (ii) A non-zero module is essentially retractable if and only if there exists a prime ideal such that Hom<sub>R</sub>. Over semiprime right nonsingular rings, a nonsingular essentially retractable module is precisely a module with non-zero dual. Moreover, over certain rings <em>R</em>, including right FBN rings, it is shown that a nonsingular module <em>M</em> with enough uniforms is essentially retractable if and only if there exist uniform retractable <em>R</em>-modules and <em>R</em>-homomorphisms with .
Dual module
Essentially retractable
Homo-related
2007
12
01
355
360
https://jsciences.ut.ac.ir/article_35080_daa38f2a160fc3e3a8b0aafa70c41eff.pdf