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Dehghani-Zadeh, Fatemeh Korean Mathematical Society 2012 대한수학회지 Vol.49 No.6
The membership of the generalized local cohomology modules $H_a^i$(M,N) of two R-modules M and N with respect to an ideal a in certain Serre subcategories of the category of modules is studied from below ($i<t$). Furthermore, the behaviour of the $n$th graded component $H_a^i(M,N)_n$ of the generalized local cohomology modules with respect to an ideal containing the irrelevant ideal as $n{\rightarrow}-{\infty}$ is investigated by using the above result, in certain graded situations.
Dehghani-Zadeh, Fatemeh Korean Mathematical Society 2016 대한수학회논문집 Vol.31 No.4
Let I and J be two ideals of a commutative Noetherian ring R and M, N be two non-zero finitely generated R-modules. Let t be a non-negative integer such that $H^i_{I,J}(N)$ is (I, J)-minimax for all i < t. It is shown that the generalized local cohomology module $H^i_{I,J}(M,N)$ is (I, J)-Cofinite minimax for all i < t. Also, we prove that the R-module $Ext^j_R(R/I,H^i_{I,J}(N))$ is finitely generated for all $i{\leq}t$ and j = 0, 1.
Dehghani Mehdi,Lee Hojun,Shahbazi Saeed,Kim Kyoung-Ho,Kang Evan S. Hyunkoo 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.81 No.7
We present a spray pyrolysis method that can form amorphous Al2O3 thin flms for dielectric applications using low-cost precursor materials. The efect of the precursor molar ratios on morphological and electrical properties of spray-coated Al2O3 thin flms was studied. For a low molar ratio of acetylacetone (AcAc) to Al ions (AcAc/Al), inhomogeneous morphology with the formation of large particles was observed. The increase in AcAc/Al improves the coverage of Al by AcAc molecules, which prevents the premature solidifcation of Al ions, resulting in compact flms with smooth surfaces. On the contrary, excessive AcAc for the high AcAc/Al leaves cracks in the flms due to the evaporation of AcAc during flm deposition. Electrical measurements on metal–insulator-metal (MIM) structures showed consistent results, and superior dielectric performance with sufciently low leakage current was observed for the optimized AcAc/Al values.
Dehghani, Hamzeh Techno-Press 2022 Advances in concrete construction Vol.13 No.2
FIB is introduced as the sole guideline for the design purpose that results in a practical relationship for the torsional capacity of concrete beams strengthened with carbon fiber-reinforced polymer (CFRP). This study applies first-order reliability method to assess the reliability evaluation of the torsional capacity of CFRP-strengthened beams on the basis of FIB guidelines. In terms of steel reinforcement losses, this study applies a corrosion model to investigate the ceaseless deterioration of the existing structure. Hence, the average of reliability indices varies between 2.68 and 2.80, indicating the reliability viewpoint of the design methodologies. The average values are somehow low compared to the target values of reliability (3.0 or 3.5) applied in the calibration stage of the FIB guideline. In this way, the partial safety factors may change in the forthcoming guideline revisions. For this aim, the reliability of strengthening ratio was applied to assess the variation in the average value of the reliability index with different partial safety factors. The performance of parametric study for the factor proved that minimum values of 1.60 and 2.32 are required for target values of reliability (3.0 and 3.5), respectively.
ON SUBDIRECT PRODUCT OF PRIME MODULES
Dehghani, Najmeh,Vedadi, Mohammad Reza Korean Mathematical Society 2017 대한수학회논문집 Vol.32 No.2
In the various module generalizations of the concepts of prime (semiprime) for a ring, the question "when are semiprime modules subdirect product of primes?" is a serious question in this context and it is considered by earlier authors in the literature. We continue study on the above question by showing that: If R is Morita equivalent to a right pre-duo ring (e.g., if R is commutative) then weakly compressible R-modules are precisely subdirect products of prime R-modules if and only if dim(R) = 0 and R/N(R) is a semi-Artinian ring if and only if every classical semiprime module is semiprime. In this case, the class of weakly compressible R-modules is an enveloping for Mod-R. Some related conditions are also investigated.
NON-GEOMETRICAL CONSTANTS OF THE MOTION FOR THE MAXIMALLY SYMMETRIC SPACETIMES
DEHGHANI M. H. The Korean Astronomical Society 1996 Journal of The Korean Astronomical Society Vol.29 No.suppl1
A systematric method of exploring the 'geometrical' and 'non-geometrical' constants of the motion for an arbitrary spacetime is presented. This is done by introducing a series of coupled differential equation for the generators of the symmetry group of Vlasov's equation. The method is applied to the case of the maximaly symmetric spectime, and the geometrical and non-geometrical constants of motion are obtained.
Electronic Ballast for HPS Lamps with Intrinsic Power Regulation over Lamp Life
Dehghani, Majid,Saghaiannejad, Seid Mortaza,Karshenas, Hamid Reza The Korean Institute of Power Electronics 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.4
This paper introduces the electronic ballast for high pressure sodium (HPS) lamps which provides power regulation during the whole lamp life without using a closed-loop power control system, in spite of large variations of lamp characteristics resulting from lamp aging. The structure of the electronic ballast and the parameters of HPS lamps are described. A mathematical model for the ballast is developed and used for the design and analysis of the ballast. A design procedure is presented to design the ballast which provides intrinsic power regulation over the whole lamp life. To improve the technical specifications of the ballast, the practical and standard constraints are considered in the design. According to the design procedure, an electronic ballast for 250-W HPS lamps is designed. All theoretical analyses are verified with the help of a semi-industrial experimental setup. The results validate that the designed ballast provides power regulation during the whole lamp life.
Results of Graded Local Cohomology Modules with respect to a Pair of Ideals
Dehghani-Zadeh, Fatemeh Department of Mathematics 2018 Kyungpook mathematical journal Vol.58 No.1
Let $R ={\oplus}_{n{\in}Z}R_n$ be a graded commutative Noetherian ring and let I be a graded ideal of R and J be an arbitrary ideal. It is shown that the i-th generalized local cohomology module of graded module M with respect to the (I, J), is graded. Also, the asymptotic behaviour of the homogeneous components of $H^i_{I,J}(M)$ is investigated for some i's with a specified property.