eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-12-28
29
3
341
347
10.22099/ijsts.2005.2810
2810
HYPERRULED SURFACES IN MINKOWSKI 4-SPACE
R. ASLANER
1
Department of Mathematics, Inönü University, 44280 Malatya, Turkey
In this paper, the time-like hyperruled surfaces in the Minkowski 4-space and their algebraic<br />invariants are worked. Also some characteristic results are found about these algebraic invariants.
http://ijsts.shirazu.ac.ir/article_2810_2fdadc0f5858b8c7c132ee7ac3a6e46b.pdf
ruled surfaces
rulings
main curvature
scalar curvature
time-like vector
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-12-28
29
3
349
356
10.22099/ijsts.2005.2811
2811
ANGULAR DEPENDENT MAGNETORESISTANCE OSCILLATION IN STAGE-2 IBr GRAPHITE INTERCALATION COMPOUND
M. BARATI
1
P. K. UMMAT
2
G. LUKE
3
W. R. DATARS
4
Department of Physics, Shiraz University, Shiraz, I. R. of Iran 71454
Department of Physics and Astronomy, McMaster University, Hamilton, ON, L8S 4M1, Canada
Department of Physics and Astronomy, McMaster University, Hamilton, ON, L8S 4M1, Canada
Department of Physics and Astronomy, McMaster University, Hamilton, ON, L8S 4M1, Canada
The angular dependent magnetoresistance oscillation (ADMRO) of the stage-2 IBr graphite<br />intercalation compound (GIC) was studied between 1.8 K and 110 K in magnetic fields between 1 and 9<br />T. There was a series of peaks in the c-axis resistance as the field direction was changed from the c axis<br />to the (001) plane. The field independence of the angular positions of the peaks, showing that the<br />oscillation is not from the Shubnikov-de Haas effect, and the presence of the oscillation at high<br />temperatures indicate that the effect is semiclassic. The location and the relative amplitudes of the peaks<br />show that the ADMRO in this compound does not follow the predictions for the symmetrical corrugation<br />model of the cylindrical Fermi surface. The reason is attributed to the presence of two cylindrical Fermi<br />surfaces and zone folding of the Fermi surface by the periodicity of the IBr lattice in this compound.
http://ijsts.shirazu.ac.ir/article_2811_d5686fab19aa01ed8a1a7bfb69baa70b.pdf
Graphite intercalation compound
ADMRO effect
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-12-28
29
3
357
366
10.22099/ijsts.2005.2812
2812
ON GENERAL RELATIVELY ISOTROPIC L-CURVATURE FINSLER METRICS
B. NAJAFI
1
A. TAYEBI
2
M. M. REZAII
3
Department of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of Iran
Department of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of Iran
Department of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of Iran
In this paper the general relatively isotropic L -curvature Finsler metrics are studied. It is<br />shown that on constant relatively Landsberg spaces, the concepts of weakly Landsbergian, Landsbergian<br />and generalized Landsbergian metrics are equivalent. Some necessary conditions for a relatively<br />isotropic L -curvature Finsler metric to be a Riemannian metric are also found.
http://ijsts.shirazu.ac.ir/article_2812_3ec2d485739429c1284f819a17e1ed16.pdf
Finsler metric
(generalized) Landsberg metric
(mean) landsberg curavture
(mean) Cartan tensor
Douglas tensor
Funk metric
Randers metric
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-12-28
29
3
367
375
10.22099/ijsts.2005.2813
2813
ELECTRON ACCELERATION AND EXCITATION PROCESSES IN THE VICINITY OF A MERCURY DISCHARGE CONSTRICTION
S. FAZLIAN
1
S. SOBHANIAN
2
A. MURADOV
3
1Faculty of Physics, University of Tabriz, Tabriz, I. R. of Iran,
Faculty of Physics, University of Tabriz, Tabriz, I. R. of Iran
Physics Dept., Baku State University, Baku, Azerbaijan
In the present paper axial distributions of plasma and floating potentials, electron and ion<br />densities and EEDF have been measured in the DL region of a Hg discharge constriction. An attempt has<br />been made for the resolution of opposing charged layer structures in DL. Excitation processes in the<br />constriction region are studied. Using the linearization method for the nonstationary balance equations<br />system and choosing appropriate discharge conditions, the step excitation rate by the electron impact for<br />6 3 P 2 →7 1 S 0 transition in Hg is determined.
http://ijsts.shirazu.ac.ir/article_2813_af8332e94ffa5ce5f445ce6c441a01ca.pdf
Double layers (DL)
EEDF
plasma parameters
excitation processes
constriction edge
excitation
rates
modulation depths
spectral lines
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-12-28
29
3
377
385
10.22099/ijsts.2005.2814
2814
INFORMATION MATRIX FOR A MIXTURE OF TWO PARETO DISTRIBUTIONS
S. NADARAJAH
1
S. KOTZ
2
1Department of Statistics, University of Nebraska, Lincoln, NE, USA, 68583
Department of Engineering Management and Systems Engineering, George Washington University, Washington, D. C. USA, 20052
The Fisher information matrix for a mixture of two Pareto distributions is derived. Numerical<br />tabulations of the matrix are also provided for practical purposes. The work is motivated by a real-life<br />example.
http://ijsts.shirazu.ac.ir/article_2814_69a91a8da9260173b19ae6d68b85daaa.pdf
Lerch function
pareto distribution
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-12-28
29
3
387
399
10.22099/ijsts.2005.2815
2815
EFFECT OF MONITORING TIME INTERVAL ON THE RESULTS OF STOCHASTIC ANALYSIS OF KARST WATER RESOURCES
M. ZARE
1
A. R. NEMATOLLAHI
2
M. RAHNEMAEI
3
Department of Geology, Shiraz University, I. R. of Iran 2Department of Statistics, Shiraz University, I. R. of Iran
Department of Statistics, Shiraz University, I. R. of Iran
Department of Irrigation, Shiraz Islamic Azad University, I. R. of Iran
Data monitoring is important in the study and analysis of hydrological behaviors of karstic<br />systems. Monitoring shows the various regimes of groundwater flow (laminar or turbulent), depletion,<br />filling, filtration and karstification degree of karst aquifers. In recent years, analyses of these data had<br />considerable advances using stochastic time series analyses. An important problem related to these<br />analyses is the constraint of financial and technical human support. If we can increase the time intervals,<br />the costs are lowered and development of new monitoring networks will be possible. In this research, the<br />effect of monitoring time intervals on the results of time series analysis and calculated hydrologic delay<br />times are studied, using bivariate analyses in spectral domain. The first (shorter) and the second (longer)<br />delay times are related to the flow of groundwater through the larger and smaller fractures of the karstic<br />system, respectively. Daily groundwater level data of three piezometers and the discharge of a spring in<br />the Maharlu karst basin in Iran (5212′ to 5328′E and 291′ to 306′N ) were acquired and then six<br />different time series having different time intervals (1, 3, 7, 10, 14 and 30 days) were extracted and<br />analyzed. The results show that the variation of the computed stochastic parameters with increasing time<br />intervals is unpredictable, but the variation of time (period) corresponding to the frequency at the peak of<br />amplitude function (curve) shows a linear and predictable relationship, which is unique for every kind of<br />karstic aquifer having different degrees of karstification.
http://ijsts.shirazu.ac.ir/article_2815_e4d792d269fba9a9da978a1f80d5196a.pdf
Karst
Time series
squared coherency
phase
amplitude
delay time
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-12-28
29
3
401
410
10.22099/ijsts.2005.2816
2816
A NEW METHOD FOR ELECTRIC FIELD OPTIMIZATION IN HIGH POWER LASER MULTILAYERS
M. H. MAHDIEH
1
M. ALAVI-NEJAD
2
Department of Physics, Iran University of Science and Technology, Narmak, Tehran, I. R. of Iran
Department of Physics, Iran University of Science and Technology, Narmak, Tehran, I. R. of Iran
Spatial distribution of electric field amplitude has an essential role in laser-induced damage<br />multi-layer coating. A new method introduced in this paper to reduce the electric field intensity<br />effectively within the high index layers in multi-layer reflectors that are irradiated by high power lasers.<br />The design is based on specific non-quarter wave pairs, assuming the number of layers is held constant.<br />Using a combination of periodic and non-periodic pairs of a non-quarter wave stack with an appropriate<br />thickness for a specific angle of incidence, minimum electric field can be obtained within the high index<br />layers for the S or P polarization. Different results can be obtained if the non-periodic pairs are placed<br />adjacent to the substrate, or to the ambient. We have shown that by the former design, a lower electric<br />field can be achieved within the layers and the mirror can be optimized. The optimization was carried<br />out for oblique incidence and the effect of angle of incidence was examined for both S and P<br />polarizations.
http://ijsts.shirazu.ac.ir/article_2816_1faf57c21d8441ae18e765ab67979c52.pdf
Optical multi-layers
high power laser mirrors
optical damage
electric field reduction
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-12-28
29
3
411
420
10.22099/ijsts.2005.2817
2817
EXTREMAL ORDERS INSIDE SIMPLE ARTINIAN RINGS
N. H. HALIMI
1
84 Manburgh Tce, Darra, QLD 4076, Australia
The aim of this paper is to study orders over a valuation ring V with arbitrary rank in a<br />central simple F-algebra Q. The relation between all of the orders is explained with a diagram. It is then<br />shown that inside Bezout order, extremal V-orders are precisely semi-hereditary. In the last section, the<br />effect of Henselization on maximal and semi-hereditary orders is examined.
http://ijsts.shirazu.ac.ir/article_2817_62d19d2ec79077ab2b70dcc65e62f64a.pdf
Dubrovin valuation rings
extremal orders
Henselization
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-12-28
29
3
421
431
10.22099/ijsts.2005.2818
2818
ON THE INVESTIGATION OF SPARK FORMATION CONDITIONS AND ENERGY GAIN IN INERTIAL CONFINEMENT FUSION
A. GHASEMIZAD
1
M. R. ESKANDARI
2
S. KHOSHBINFAR
3
M. KAMRAN
4
1Department of Physics, Faculty of Science, University of Guilan, Rasht, I. R. of Iran,
Department of Physics, Shiraz University, Shiraz, I. R. of Iran
Department of Physics, Faculty of Science, University of Guilan, Rasht, I. R. of Iran
Department of Physics, Faculty of Science, University of Guilan, Rasht, I. R. of Iran
In isobaric models for inertial confinement fusion it is assumed that the target configuration<br />at stagnation time (maximum compression) consists of two regions, hot spark and cold fuel, respectively.<br />Here the conditions of spark formation and ignition in hydrogen equimolar isotopes in central spark<br />ignition are investigated and permissible values of Hs and Ts are evaluated numerically. By introducing a<br />dimensionless parameter, ψs, the class of targets are considered by the specific value of ψs. Finally,<br />limiting fuel energy gain curve (Gf*) as a function of ignition energy (Eign) allows different implosion<br />velocities to be calculated. This result is in good agreement with more complex hydrodynamic models.
http://ijsts.shirazu.ac.ir/article_2818_e2c40591159c56838c97453e3778604e.pdf
Central spark ignition
spark parameter
isobaric model
limiting gain curve
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-02-27
29
3
433
454
10.22099/ijsts.2005.2819
2819
USING FUZZY KNOWLEDGE OF A NUISANCE PARAMETER FOR HYPOTHESIS TESTING
J. BEHBOODIAN
behboodian@stat.susc.ac.ir,
1
A. MOHAMMADPOUR
2
1Department of Mathematics, Shiraz Islamic Azad University, Shiraz, I. R. of Iran
Department of Statistics, Faculty of Mathematics and Computer Science, Amirkabir University of Technology, 424 Hafez Ave., Tehran, I. R. of Iran, 15914
The problem of hypothesis testing with a nuisance parameter is considered. Two methods for<br />using fuzzy knowledge on the nuisance parameter to test hypotheses are suggested. These methods are<br />neither a pure classical nor a pure Bayesian approach to hypothesis testing, but rather related to both. A<br />few known examples and their applications, which cannot be studied by the parametric statistical<br />methods, are discussed.
http://ijsts.shirazu.ac.ir/article_2819_7710b20c222e8a91298a9202beade963.pdf
Fuzzy Statistics
defuzzified distribution
weighted defuzzification-Estimator
exchangeable
normal Distribution
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-02-27
29
3
455
470
10.22099/ijsts.2005.2820
2820
ON THE INTEGRAL INVARIANTS OF KINEMATICALLY GENERATED RULED SURFACES
H. B. KARADAG
1
S. KELES
2
Department of Mathematics, Faculty of Sciences and Arts, Inönü University, 44069 Malatya, Turkey
Department of Mathematics, Faculty of Sciences and Arts, Inönü University, 44069 Malatya, Turkey
In this paper, the dual area vector of a closed dual spherical curve is kinematically generated<br />and the dual Steineer vector of a motion are extensively studied by the methods of differential geometry.<br />Jacobi’s Theorems, known for real curves, are investigated for closed dual curves. The closed trajectory<br />surfaces generated by an oriented line are fixed in a moving rigid body in IR3 , in which the closed dual<br />curves from E. Study’s transference principle is studied. The integral invariants of these closed ruled<br />surfaces are calculated by means of the area vector. Moreover, some theorems, results and examples are<br />given.
http://ijsts.shirazu.ac.ir/article_2820_8a3f1287b2fff270d6c689fd8bbe547e.pdf
Mechanism
kinematics
area vectors
ruled surfaces
invariants and motions
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-02-27
29
3
471
480
10.22099/ijsts.2005.2821
2821
AIR POLLUTION ASSESSMENT IN SHIRAZ BY PASSIVE SAMPLING TECHNIQUES
K. HADAD
hadadk@shirazu.ac.ir
1
A. SAFAVI
2
R. TAHON
3
1Department of Nuclear Engineering, Shiraz University, Shiraz, I. R. of Iran, 71345
Department of Chemistry, Shiraz University, Shiraz, I. R. of Iran, 71454
ETI Group Burgeap, 92772 Boulogne Billancourt Cedex, France
The air quality in Shiraz was assessed based on a one-week passive sampling campaign.<br />During the first week of the summer 2003, about 400 passive samplers were used in groups of two and<br />three, so that 187 sampling stations covered all of Shiraz. Pollutant gases including SO2, NO2 and BTX<br />(benzene, toluene and xylene) were sampled by diffusive sampling tubes. Collected samples were<br />analyzed and pollutant concentrations were determined by using ion chromatography, spectrophotometry<br />and gas chromatography techniques. The result of the analysis shows that SO2 and NO2 concentrations<br />exceed national and international standards in the central and southern parts of Shiraz. Weekly averaged<br />concentrations of benzene, toluene and xylene at all sampling sites were 105, 206 and 123 μg/m3, which<br />exceed national and international standards.<br />Based on the results, more than 15% of Shiraz's population (180,000 out of 1.2 million people)<br />were exposed to high levels of NO2 during this survey period.
http://ijsts.shirazu.ac.ir/article_2821_fdda54545c67a6cf90ba3218724b577c.pdf
Urban air pollution
passive sampling
air quality
BTX concentration
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-02-27
29
3
481
495
10.22099/ijsts.2005.2822
2822
TRANSFORMATION SEMIGROUPS AND EXACT SEQUENCES
F. AYATOLLAH ZADEH SHIRAZI
1
Department of Mathematics, Faculty of Science, University of Tehran, Enghelab Ave., Tehran, I. R. of Iran
This text carries out some ideas about exact and P− exact sequences of transformation<br />semigroups. Some theorems like the short five lemma (Lemma 1.3 and Lemma 2.3) are valid here as in<br />exact sequences of R − modules.
http://ijsts.shirazu.ac.ir/article_2822_838138855031870967c60812ee721d3f.pdf
a − minimal set
exact sequence
P− exact sequence
proximal relation
transformation semigroup
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-02-27
29
3
497
505
10.22099/ijsts.2005.2823
2823
ON GENERAL RELATIVELY ISOTROPIC MEAN LANDSBERG METRICS
B. NAJAFI
1
A. TAYEBI
2
M. M. REZAII
3
Department of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of Iran
Department of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of Iran
Department of Mathematics and Computer Science of Amir-Kabir University, Tehran, I. R. of Iran
The general relatively isotropic mean Landsberg metrics contain the general relatively<br />isotropic Landsberg metrics. A class of Finsler metrics is given, in which the mentioned two concepts<br />are equivalent. In this paper, an interpretation of general relatively isotropic mean Landsberg metrics is<br />found by using C-conformal transformations. Some necessary conditions for a general relatively<br />isotropic mean Landsberg metric, as well as generalized Landsberg metric to be a Riemannian metric are<br />also found.
http://ijsts.shirazu.ac.ir/article_2823_90a1f40868e91842e0619d4d84578a41.pdf
Finsler structure
Cartan connection
(generalized) Landsberg metric
scalar curvature
C2-like
space
c-conformal transformation
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-02-27
29
3
507
514
10.22099/ijsts.2005.2824
2824
THE STRUCTURE OF (α,β)-DERIVATIONS OF TRIANGULAR RINGS
M. N. GHOSSEIRI
1
Department of Mathematics, Kurdistan University P. O. Box 416, Sanandaj, I. R. of Iran
Let R and S be reduced rings with identities whose idempotents are central, and let M be an<br />(R, S)-bimodule such that annr (M)=0. In this paper, we determine first the structure of automorphisms of<br />the triangular ring, <br /><br /><br /><br /><br />=<br />S<br />R M<br />T<br />0<br />, and then, for all automorphisms α ,β of T we determine the structure<br />of (α,β)-derivations of T.
http://ijsts.shirazu.ac.ir/article_2824_9c3c1808dd2dab02b817767301f7eb17.pdf
Triangular ring
automorphism
(α
β ) -derivation
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-02-27
29
3
515
521
10.22099/ijsts.2005.2825
2825
INSTABILITY OF SOLUTIONS OF CERTAIN NONLINEAR VECTOR DIFFERENTIAL EQUATIONS OF ORDER SEVEN
C. TUNC
1
E. TUNC
2
1Department of Mathematics, Faculty of Sciences and Literature, Yüzüncü Yil University, 65080, Van, Turkey
Department of Mathematics, Faculty of Science and Literature, Gaziosman Paşa University, 60080, Tokat, Turkey
Sufficient conditions are established under which the zero solution X = 0 of equation (2) is<br />unstable.
http://ijsts.shirazu.ac.ir/article_2825_a8ec38612da6961acdeef265e22fd009.pdf
Nonlinear differential equations
seventh order
instability
Lyapunov’s second (direct) method
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-02-27
29
3
523
529
10.22099/ijsts.2005.2826
2826
ON THE MOMENTS OF LKD
A BAZARGAN-LARI
1
Department of Statistics, Shiraz University, Shiraz, I. R. of Iran
The mean and variance of the Lagrangian Katz family of distribution (LKD), the basic<br />Lagrangian Katz distribution of Type I (LKD-I) and Type II (LKD-II) are provided in an easy method.<br />The recurrence relation between the non-central, central and factorial moments, and the recurrence<br />relation between moments and cumulants of LKD, LKD-I and LKD-II are given. The first four<br />cumulants of LKD-I and LKD-II are provided.
http://ijsts.shirazu.ac.ir/article_2826_e500a7576eb164d442bdb20b3d6415b8.pdf
Lagrangian Katz Family of Distribution (LKD)
recurrence relations
central
non-central and
factorial moments
cumulants
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2005-02-27
29
3
531
539
10.22099/ijsts.2005.2827
2827
CONFORMAL VECTOR FIELDS ON TANGENT BUNDLE OF A RIEMANNIAN MANIFOLD
S. HEDAYATIAN
1
B. BIDABAD
2
Faculty of Mathematics, Amir-Kabir University of Technology, Hafez Ave. 15914, Tehran, I. R. of Iran
Faculty of Mathematics, Amir-Kabir University of Technology, Hafez Ave. 15914, Tehran, I. R. of Iran
Let M be an n-dimensional Riemannian manifold and TM its tangent bundle. The<br />conformal and fiber preserving vector fields on TM have well-known physical interpretations and have<br />been studied by physicists and geometricians. Here we define a Riemannian or pseudo-Riemannian lift<br />metric g on TM , which is in some senses more general than other lift metrics previously defined on<br />TM , and seems to complete these works. Next we study the lift conformal vector fields on (TM,g) and<br />prove among the others that, every complete lift conformal vector field on TM is homothetic, and<br />moreover, every horizontal or vertical lift conformal vector field on TM is a Killing vector.
http://ijsts.shirazu.ac.ir/article_2827_9795fa11b38852d02d951bd9f80126d8.pdf
Complete lift metric
Conformal
Homothetic
Killing and Fiber-preserving vector fields