Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
28
2
2004
12
26
GREEN FUNCTION OF AXISYMMETRIC MAGNETOSTATICS
197
204
EN
F.
DINI
Department of Plasma Physics, Nuclear Fusion Research Center, P. O. Box 14155-1339,
Amirabad, Tehran, I. R. of Iran
S.
KHORASANI
Department of Plasma Physics, Nuclear Fusion Research Center, P. O. Box 14155-1339,
Amirabad, Tehran, I. R. of Iran
R.
AMROLLAHI
Faculty of Physics, Amir Kabir University of Technology, Hafez Ave.,
Tehran, I. R. of Iran
10.22099/ijsts.2004.2850
A simple new closed form of the Green function for axisymmetric magnetostatic problems<br />is found analytically in cylindrical coordinates. The result is verified by applying several examples.
Magnetostatics,green functions,partial differential equations,electromagnetics
http://ijsts.shirazu.ac.ir/article_2850.html
http://ijsts.shirazu.ac.ir/article_2850_78f46ca37722cee176b3d5c36468644a.pdf
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
28
2
2004
12
26
RING RESONATOR COUPLED M-Z ALL-OPTICAL SWITCH BY USING A PUMPED NONLINEAR DIRECTIONAL COUPLER
205
210
EN
A.
BANANEJ
Institute of Modern Optics, Department of Physics, Harbin Institute of Technology
Harbin 150001, China
C. F.
Li
Institute of Modern Optics, Department of Physics, Harbin Institute of Technology
G. M.
XU
Institute of Modern Optics, Department of Physics, Harbin Institute of Technology
10.22099/ijsts.2004.2851
We propose a new ring resonator side-coupled M-Z interferometer all-optical switch through<br />the pumped nonlinear directional coupler. By controlling pump power P to lead the coupler reflectivity<br />r approaching to 1, the resonator finesse will be enhanced dramatically, and then the minimum<br />switching power in silica-based practice devices can be obtained. As a sample, we use a nonlinear<br />coupler made by two erbium-doped fibers, and launch a 514.5nm-pump light into one of the cores to<br />make the reflective- index difference between two cores. Based on the asymmetric-coupler theory, we<br />simulate the relationship between r and P , and show that the required pump power is only 0.8mW<br />for r →1 .
All optical switches,Mach-Zehnder interferometer,switching power,ring resonator,directional
coupler,Erbium-doped fiber,nonlinear refractive index
http://ijsts.shirazu.ac.ir/article_2851.html
http://ijsts.shirazu.ac.ir/article_2851_e5f5dfd855e274020bf319426b241bba.pdf
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
28
2
2004
12
26
THE STRONG LAW OF LARGE NUMBERS FOR PAIRWISE NEGATIVELY DEPENDENT RANDOM VARIABLES
211
217
EN
H. R.
NILI SANI
Department of Statistics, School of Mathematical Sciences, Ferdowsi University, Mashhad, I. R. of Iran
H. A.
AZARNOOSH
Department of Statistics, School of Mathematical Sciences, Ferdowsi University, Mashhad, I. R. of Iran
A.
BOZORGNIA
Department of Statistics, School of Mathematical Sciences, Ferdowsi University, Mashhad, I. R. of Iran
10.22099/ijsts.2004.2852
In this paper, strong laws of large numbers (SLLN) are obtained for the sums ƒ°=<br />n<br />i<br />i X<br />1<br />, under<br />certain conditions, where {X ,n . 1} n is a sequence of pairwise negatively dependent random variables.
Strong law of large numbers,pairwise negatively dependent random variables
http://ijsts.shirazu.ac.ir/article_2852.html
http://ijsts.shirazu.ac.ir/article_2852_6771ec51729c273c4892533588694959.pdf
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
28
2
2004
12
26
CONTROLLING CHAOS IN 2-DIMENSIONAL SYSTEMS
219
226
EN
L. M.
SAHA
Department of Mathematics, Zakir Husain College, University of Delhi, New Delhi – 110002, India
G. H.
ERJAEE
Mathematics Department, College of Science, Shiraz University, Shiraz, I. R. of Iran
M.
BUDHRAJA
Department of Mathematics, Shivaji College, University of Delhi,
New Delhi, 110027, India
10.22099/ijsts.2004.2872
A chaos control method suggested by Erjaee has been reviewed. It has been shown that this<br />technique can be applied in various evolutionary systems of 2-dimensional types. The method has been<br />applied for cases of the Henon map, as well as Burger’s map. The limitations of the control technique<br />have also been discussed by considering the Standard Map and the Gumowski-Mira map. The results<br />obtained through numerical calculations are very interesting and significant. This technique has some<br />advantages over many other techniques of chaos control in discrete systems.
asymptotic stability,control parameter,chaos
http://ijsts.shirazu.ac.ir/article_2872.html
http://ijsts.shirazu.ac.ir/article_2872_3e4c93e9d7f22c0baf6faf6a1cb17373.pdf
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
28
2
2004
12
26
STUDY OF THE DISTORTED LAYER STRUCTURE OF SILICON WAFERS BY THE METHOD OF PLASMA-CHEMICAL ETCHING AFTER MECHANICAL MACHINING PROCESSES
227
234
EN
H.
BIDADI
Faculty of physics, Tabriz University, Tabriz, I. R. of Iran, 51664
S.
SOBHANIAN
Faculty of physics, Tabriz University, Tabriz, I. R. of Iran, 51664
SH.
HASANLI
National Academy of Sciences, Azerbaijan Republic
M.
MAZIDI
Faculty of physics, Tabriz University, Tabriz, I. R. of Iran, 51664
M.
KARIMI
Faculty of physics, Tabriz University, Tabriz, I. R. of Iran, 51664
10.22099/ijsts.2004.2873
In this experimental work, by using the method of plasma-chemical etching, we have dealt<br />with the causes of the creation of a distorted layer on the surface of silicon wafers during mechanical<br />machining processes, in addition, the elucidation of connections between the structure of this layer and<br />characteristic parameters of the mechanical strength of these wafers have been studied. Experimental<br />results obtained at room temperature show that after cutting and grinding processes, the mean value of<br />mechanical strength σ, which is apparently independent of the types of conductivity, is significantly<br />lower than its theoretical value. Analysis of the dependence of mechanical parameters on the time of<br />plasma-chemical etching indicates that the lower values obtained for the mechanical strength of silicon<br />wafers is basically due to the existence of a distorted layer and corresponding internal stresses created on<br />the surface of these wafers after mechanical machining. Plasma-chemical etching leads to an increase in<br />σ value. Dependency of σ on the etching time is qualitatively described by the microstructure of the<br />distorted layer and parameters of the micro relief surface of the wafers. Correlation between parameters<br />σ, H, K and the microstructure of the distorted layer allows us to suggest the method of plasma chemical<br />etching as a method of investigating the microstructure of the distorted layer after the mechanical<br />machining processes.
Mechanical properties,silicon wafers,cutting,grinding and etching
http://ijsts.shirazu.ac.ir/article_2873.html
http://ijsts.shirazu.ac.ir/article_2873_cb44f197ef0ec90cfe9655a260ba8284.pdf
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
28
2
2004
12
26
COUNTEREXAMPLES IN a−MINIMAL SETS
235
256
EN
F.
AYATOLLAH ZADEH SHIRAZI
Department of Mathematics, Faculty of Science, Tehran University, Enghelab Ave., Tehran, I. R. of Iran
M.
SABBAGHAN
Department of Mathematics, Faculty of Science, Tehran University, Enghelab Ave., Tehran, I. R. of Iran
10.22099/ijsts.2004.2874
Several tables have been given due to a − minimal sets. Our main aim in this paper is to<br />complete these tables by employing several examples.
a − minimal set,Distal,enveloping semigroup,proximal relation,trasformation semigroup
http://ijsts.shirazu.ac.ir/article_2874.html
http://ijsts.shirazu.ac.ir/article_2874_13052c36b479587657673f3fd3003a4f.pdf
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
28
2
2004
12
26
IMPROVED MIT BAG MODEL WITH HYPER CENTRAL INTERACTING POTENTIAL
257
266
EN
A. A.
RAJABI
Department of physics, Shahrood University of Technology, P. O. Box 36155-316 Shahrood, I. R of Iran,
10.22099/ijsts.2004.2875
An improved MIT bag model with hyper central interactions is used to calculate the static<br />properties of hadrons containing u, d, s and c quarks. We present a theoretical approach to the internal<br />structure of three-body hyper central interacting quarks in a hadron, in which we take hadron as a bag.<br />We discuss a few of the results obtained using a six-dimension harmonic oscilator (h.o) potential, having<br />a two-body character, which turns out to be a hyper central confinement part. The other potential is sixdimensional,<br />which is attractive for small separation, originating from the color charge of hyper color<br />term. However the potential can easily be generalized in order to allow a systematic analysis. We<br />calculate the relativistic wave function for quarks in a scalar-vector hyper central potential, analytically.<br />Finally, vanishing the normal component of vector current at the surface of the baryon bag as a boundary<br />condition equivalent to confinement, results in the static properties and the strength of hyper Coulomb<br />like potential parameter. This depends on the mass parameters contrary to almost all previous versions.<br />The calculated static properties for baryon are better than in the uncorrected versions of the model.<br />PACS index 12.39 .Ba, 12.39. Ki, 12.39. Pn
Hyper central interaction,hadron,static properties,dirac equation,charge radius,magnetic
moment
http://ijsts.shirazu.ac.ir/article_2875.html
http://ijsts.shirazu.ac.ir/article_2875_9facb82266e750ab197e43b975176778.pdf
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
28
2
2004
12
26
DIRECT SYSTEM AND DIRECT LIMIT OF v H -MODULES
267
275
EN
M.
GHADIRI
Department of Mathematics, Yazd University, Yazd, I. R. of Iran
mghadiri@yazduni.ac.ir
B.
DAVVAZ
Department of Mathematics, Yazd University, Yazd, I. R. of Iran
10.22099/ijsts.2004.2876
The largest class of algebraic hyper structures satisfying the module like axioms is the v H -<br />module. In this paper, we consider the category of v H -modules and prove that the direct limit always<br />exists in this category. Direct limits are defined by a universal property, and so are unique. The most<br />powerful tool in order to obtain a module from a given v H - module is the quotient out procedure. To use<br />this method we consider the fundamental equivalence relationε * , and then prove some of the results<br />about the connection between the fundamental modules, direct systems and direct limits.
H -ring,v H -module,direct system,direct limit,fundamental relation,fundamental module
http://ijsts.shirazu.ac.ir/article_2876.html
http://ijsts.shirazu.ac.ir/article_2876_94edaedce6187b8b1a0698546845c448.pdf
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
28
2
2004
12
26
ANALYSIS OF SPATIAL POINT PATTERNS BY KERNEL IDENTIFICATION
277
288
EN
M. Q.
VAHIDI-ASL
Department of Statistics, Shahid Beheshti University, Evin, Tehran, I. R. of Iran 19839
M. R.
FAGHIHI
Department of Statistics, Shahid Beheshti University, Evin, Tehran, I. R. of Iran 19839
10.22099/ijsts.2004.2877
In the analysis of spatial point patterns, complete spatial randomness (CSR) hypothesis,<br />which is a restriction of a homogenous Poisson process to study region A, operates as a dividing<br />hypothesis between “regular” and “aggregated” patterns. Meanwhile, many alternatives to CSR in<br />aggregated patterns are extensions of homogenous Poisson processes themselves. Therefore, when the<br />CSR hypothesis is rejected, results related to Poisson processes may be used to formulate plausible<br />alternatives to CSR. In this paper, we propose a new statistic for testing CSR and then by applying it in<br />conjunction with a notion of kernels of a point pattern, we determine the “parents” of a Poisson cluster<br />process when the CSR hypothesis is rejected and a Neyman-Scott process is assumed for the point<br />pattern under alternative hypothesis. We have made power studies for our test statistic by simulation, and<br />have also surveyed the performance of our method on a certain point pattern. Finally, the whole method<br />is carried on certain real life data.
Spatial point patterns,complete spatial randomness,poisson processes,Neyman-Scott processes,cluster analysis
http://ijsts.shirazu.ac.ir/article_2877.html
http://ijsts.shirazu.ac.ir/article_2877_5bd76b51ec7c1bd86de9a2a44109d41e.pdf
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
28
2
2004
12
26
REAL GROUP ALGEBRAS
289
298
EN
A.
EBADIAN
Current address: Department of Mathematics, Urmia University, I. R. of Iran
a.ebadian@urmia.ac.ir
A. R.
MEDGHALCHI
Faculty of Mathematics, Teacher Training University, Tehran, I. R. of Iran, 15614
10.22099/ijsts.2004.2878
In this paper we initiate the study of real group algebras and investigate some of its aspects.<br />Let L1 (G) be a group algebra of a locally compact group G,τ :G →G be a group homeomorphism<br />such that τ 2 =τοτ = 1, the identity map, and Lp (G,τ ) = { f ∈ Lp (G) : fοτ = f } ( p ≥ 1) . In this<br />paper, among other results, we clarify the structure of Lp (G,τ ) and characterize amenability of<br />L1 (G,τ ) and identify its multipliers.
Real Banach algebra,amenability,multiplier,derivation,group involution
http://ijsts.shirazu.ac.ir/article_2878.html
http://ijsts.shirazu.ac.ir/article_2878_fd81bbe40553022c0d8890f0037844bb.pdf
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
28
2
2004
12
26
THE INVERSE OF COVARIANCE MATRICES FOR THE ARMA (p, q) CLASS OF PROCESSES
299
305
EN
R.
CHINIPARDAZ
Department of Statistics, University of Shahid Chamran, Ahvaz, I. R. of Iran
chinipardaz_r@scu.ac.ir,
T. F.
COX
Unilever Research Port Sunlight, Quarry Road East, Bebington, Wirral, CH633JW, UK
10.22099/ijsts.2004.2879
Analysis of time series data can involve the inversion of large covariance matrices. For the<br />class of ARMA (p, q) processes there are no exact explicit expressions for these inverses, except for the<br />MA (1) process. In practice, the sample covariance matrix can be very large and inversion can be<br />computationally time consuming and so approximate explicit expressions for the inverse are desirable.<br />This paper offers some of these approximations.
ARMA processes,band matrix,covariance matrix
http://ijsts.shirazu.ac.ir/article_2879.html
http://ijsts.shirazu.ac.ir/article_2879_e6dd3db8174e2c4874cb614f1a0869d6.pdf