• Korean Journal of Mathematics
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• 제32권1호
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• pp.83-95
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• 2024

The Quaternionic Dirac operator proves instrumental in tackling various challenges within spectral geometry processing and shape analysis. This work involves the introduction of the quaternionic Dirac operator on a symplectic submanifold of an exact symplectic product manifold. The self adjointness of the symplectic quaternionic Dirac operator is observed. This operator is verified for spin ${\frac{1}{2}}$ particles. It factorizes the Hodge Laplace operator on the symplectic submanifold of an exact symplectic product manifold. For achieving this a new complex structure and an almost quaternionic structure are formulated on this exact symplectic product manifold.

• Journal of the Korean Physical Society
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• 제73권11호
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• pp.1631-1636
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• 2018

Unpolarized 1.047-GeV proton inelastic scatterings from the Ni isotopes $^{62}Ni$ and $^{64}Ni$ are analyzed phenomenologically employing an optical potential model and the first-order collective model in the relativistic Dirac coupled channel formalism. The Dirac equations are reduced to $Schr{\ddot{o}}dinger-like$ second-order differential equations, and the effective central and spin-orbit optical potentials are analyzed by considering the mass-number dependence. The multistep excitation via the $2^+$ state is found to be important for the $4^+$ state excitation in the ground state rotational band for proton inelastic scatterings from the Ni isotopes. The calculated deformation parameters for the $2^+$ and the $4^+$ states of the ground state rotational band and for the first $3^-$ state are found to agree pretty well with those obtained from nonrelativistic calculations.

• 전기전자학회논문지
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• 제6권2호
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• pp.119-127
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• 2002

수치해석을 이용하여 전력 BJT의 정특성을 분석하는 방법을 제안한다. 고농도의 불순물이 주입된 영역에서 반송자 농도를 정교하게 구하기 위해 Fermi-Dirac 통계를 고려하며, 베이스 영역에서 재결합 전류를 계산하기 위해 Philips Unified 이동도 모델과 SRH 및 Auger 생성-재결합 모델을 사용한다. 제안된 방법을 검증하기 위해 현재 산업체에서 사용중인 전력 BJT의 베이스 전류를 $1.0[{\mu}A]$에서부터 $3.5[{\mu}A]$까지 $0.5[{\mu}A]$ 단위로 증가시키면서 컬렉터 전류의 실측치와 BANDIS와 비교한 결과 8.9%이내의 상대오차를 보였다.

• 대한기계학회논문집A
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• 제27권5호
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• pp.833-839
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• 2003

The effects of stiffeners on the modal characteristics of rectangular plates are investigated. A modeling method for the modal analysis of rectangular plates with stiffeners is presented. A mass density Dirac's delta function is used to idealize the stiffeners mathematically. The equations of motion for the plates are derived and transformed into a dimensionless form. To confirm the accuracy of the method presented in this study, numerical result are obtained and compared to those of a commercial program. The mode shape variations due to some parameter variations are also exhibited.

• 생태와환경
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• 제36권3호통권104호
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• pp.344-355
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• 2003

논은 우리나라 총 면적의 12%를 차지하며, 인간활동이 이루어지는 토지이용 중 가장 많은 면적으로 비점오염분야에서 중요한 의미를 가진다. 논은 시비가 이루어지기 때문에 논표면수의 수질변화 폭이 매우 커 지표배수가 이루어지는 시점에 따라 논에서의 부하량에 큰 영향을 미치기 때문에 논에서의 오염부하량산정과 최적관리기법개발에 있어 획일적인 원단위 적용에는 한계가 있다. 뿐만 아니라 기존에 개발된 유역모형의 대부분은 논을 포함하고 있지 않거나 포함하더라도 논에서의 충분한 기작을 모의할 수 없어 우리나라의 적용에 있어서 제한점을 가지므로 앞으로의 합리적인 오염총량제 적용을 위해서는 논모형의 개발이 절실하다. 그러나 논은 담수라는 기능을 가지므로 유역모형과 같은 물리적인 반응보다는 수질모형과 같은 생화학적 반응이 우세하리라 판단된다. 논을 하나의 얕은 호소로 간주하여 호소모형의 적용이 가능하나 이를 위한 수많은 인자 결정에 많은 어려움이 있을 것으로 판단된다. 그러나 논에서의 영농활동은 거의 유사한 시기에 해마다 반복적으로 일어나며, 동일한 양과 형태의 시비가 이루어지며 완전낙수에 의해 다음해의 수질에 영향을 거의 미치지 않으므로. 오히려 간단한 반응공식으로도 충분한 해석이 가능하리라 판단된다. 본 연구에서는 이러한 형태의 영농활동이 이루어지는 논에서의 시비와 바닥에서의 용출에 의한 영향을 dirac deltal function과 continuous source function을 이용하여 모형을 개발하여 지하수관개지역과 지표수관개지역을 대상으로 보정 및 검증결과 높은 적용가능성을 나타내었다. 앞으로의 연구방향은 논에서의 장기적인 모니터링과 여러 지역의 적응을 통한 논 모형의충분한 검증을 실시함으로써, 논에서의 오염부하량 산정과 BMPs개발 뿐 아니라, 기존의 유역모형에 연결함으로써 우리나라 오염총량제의 합리적인 적용이 이루어져야 할 것으로 판단된다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.181-186
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• 1998

A modelling method for the vibration analysis of rotating cantilever plates with a concentrated mass is presented. The equations of motion for the rotating plates with a concentrated mass located in an arbitrary position are derived. For the modelling of the concentrated mass, a mass density Dirac delta function is used. The effects of concentrated mass and its location, angular speed, and hub radius of the rotating plate on the natural frequencies are studied. Particularly, mode shape variations due to some parameter variations are investigated.

• 전자통신동향분석
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• 제38권1호
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• pp.17-25
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• 2023

Topological insulators (TIs) emerge as one of the most fascinating and amazing material in physics and electronics. TIs intrinsically possess both gapless conducting surface and insulating internal properties, instead of being only one property such as conducting, semiconducting, and insulating. The conducting surface state of TIs is the consequence of band inversion induced by strong spin-orbit coupling. Combined with broken inversion symmetry, the surface electronic band structure consists of spin helical Dirac cone, which allows spin of carriers governed by the direction of its momentum, and prohibits backscattering of the carriers. It is called by topological surface states (TSS). In this paper, we investigated the TIs materials and their unique properties and denoted the fabrication method of TIs such as deposition and exfoliation techniques. Since it is hard to observe the TSS, we introduced several specialized analysis tools such as angle-resolved photoemission spectroscopy, spin-momentum locking, and weak antilocalization. Finally, we reviewed the various fields to utilize the unique properties of TIs and summarized research trends of their applications.

• 한국안전학회지
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• 제4권1호
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• pp.47-58
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• 1989

This paper treats the vibration analysis of a simply supported rectangular plate stiffened with viscoelastic beams. The effect of viscoelastic beams on the vibration of the plate is analyzed by using Dirac delta function and the equation of motion can be expressed only one equation. The frequency equation is obtained by applying Laplace transformation. The effect of volumes, numben and aspect ratios of beam on the frequency of the plate is analyzed.

• 한국소음진동공학회논문집
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• 제23권4호
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• pp.338-346
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• 2013

Equations of motion of a rotating blade considering pre-twist angle, cross section taper and a concentrated mass are derived using the hybrid deformation variable modeling method. For the modeling of a concentrated mass which is located at an arbitrary position of the blade, a Dirac delta function is employed for the mass density function. The final equations for the vibration analysis are transformed into a dimensionless form using several dimensionless parameters. The effects of the dimensionless parameters on the vibration characteristics of the rotating blade are investigated through numerical analysis.

• 소음진동
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• 제10권2호
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• pp.312-318
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• 2000

A modeling method for the vibration analysis of rotating cantilever plastes with stiffeners is presented. The equations of motion for the plates aer derived and trnasformed into a dimensionless form. A mass density Dirac's delta function is used to idealize the stiffener mathematically. The effects of stiffeners on the model characteristics of the plate are investigated, and mode shape variations due to some parameter variation are exhibited. It is found that veering phenomena occur between some loci and associated mode shapes change significantly during the veering phenomena.