• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.506-511
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• 2007

Mechanical behavior of copper nanowire is investigated. An FCC nanowire model composed of 1,408 atoms is used for MD simulation. Simulations are performed within NVT ensemble setting without periodic boundary conditions. $Nos\acute{e}-Poincar\acute{e}$ MD algorithm is employed to guarantee preservation of Hamiltonian and temperature. Numerical tensile tests of Nanowire are carried out with constant strain rate. Additionally, temperature and strain rate effects are considered. Stress-strain curve is constructed from the calculated Cauchy stresses and specified strain values. In (22,4,4) Copper nanowire, non-linear behavior appears around ${\epsilon}\simeq0.09.$ At this instance, starting of structural reorientations are observed. At the onset of reorientation, the modulus characteristics are also investigated.

• 환경생물
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• 제20권4호
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• pp.287-293
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• 2002

원시림이 없는 한국에 산림생태계 이해에 근원이 될 자연림은 매우 중요한 의미를 가진다. 설악산에 존재하는 몇몇 전나무 고목림의 자연성을 판단하기 위하여 국제적으로 통용되는 원시림 혹은 자연림의 특징과 임분 동태학을 산림생태계 변화(천이)의 기본으로 상정하고 조사를 진행하였다. 비록 면적은 좁지만 모든 조사지역은 자연성을 확실히 보이고 있으며 수진된 기초자료는 한국 자연림 연구의 밑거름이 되리라 사료된다.

• KIEAE Journal
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• 제7권3호
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• pp.71-79
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• 2007

The starting point of successful building production process is the feasibility study of the project. If the feasibility study is poor which is affected in direct production processes such as designing and engineering, it incurs a great unrecoverable loss to the company. The government institutionalized the feasibility study for projects that budgets over 50billion won in an effort to ensure competitiveness of the construction industry after IMF; however, the system and effort to created systematic studies or guidance preparation for private construction development projects are lacking in great deal. Therefore, the objective of this study is to establish the analysis factors of feasibility study and evaluation standard by systematic analysis in consideration of the changes of various variables and mutual relationships using system dynamics technique for office buildings among commercial buildings.

• 약학회지
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• 제60권2호
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• pp.78-84
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• 2016

N-Phenylthiourea derivatives and catechol oxidase receptor complex was studied using molecular mechanics method. The starting structure was adopted from the protein databank and the calculation of energy minimization and molecular dynamics was performed with AMBER package. The molecular dynamics showed that the simulation time span of 20 ns was long enough to observe the interaction profile and stationary ligand-receptor configuration in the complex. The conformation of the ligand was related to the interaction to the receptor and the efficacy was also interpreted in this context.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.433-438
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• 2007

Mechanical behavior of copper Nanowire is investigated, An FCC Nanowire model composed of 1,408 atoms is used for NID simulation, Simulations are performed within NVT ensemble setting without periodic boundary conditions, Nose-Poincare MD algorithm is employed to guarantee preservation of Hamiltonian. Numerical tensile tests are carried out with constant strain rate, Stress-strain curve is constructed from the calculated Cauchy stresses and specified strain values, Non-linear behavior appears around $\varepsilon$=0.064, At this instance, starting of structural reorientations are observed.

• 제어로봇시스템학회논문지
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• 제14권12호
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• pp.1266-1269
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• 2008

We propose an integral sliding mode control for robot manipulators guaranteeing that sliding motion exists starting from an initial time. Also, we prove the asymptotic stability for robot manipulators using three important properties in the robot dynamics: skew-symmetry, positive-definiteness, and boundedness of robot parameter matrices. From illustrative examples, we show that the proposed method effectively controls for robot manipulators.

• 천문학회보
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• 제39권2호
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• pp.97.1-97.1
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• 2014

We clarify the dynamics connecting a solar flare and a coronal mass ejection (CME) based on the results of a magnetohydrodynamic (MHD) simulation starting from a nonlinear force-free field (NLFFF) in Inoue et al. 2014. In previous studies, many authors proposed numerous candidates for triggering processes of a solar flare and the associated CME. Among them, the tether-cutting reconnection or the torus instability has been supported by recent simulations and observations. On the other hand, our MHD simulation in accordance with more realistic situations show that highly twisted field lines are first produced through a tether-cutting reconnection between the twisted field lines in the NLFFF, and then the newly formed, strongly twisted field erupts away from the solar surface because of a loss of equilibrium. This dynamics corresponds to the onset of a solar flare. Furthermore we have found that the strongly twisted erupting field reconnect with the weakly twisted ambient field during the eruption, creating a large flux tube, and then it rises over a critical height of the torus instability to trigger a CME. From these results, we conclude that the coupled process of tether-cutting reconnection and torus instability is important in the flare-CME relationship.

• Structural Engineering and Mechanics
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• 제73권1호
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• pp.65-73
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• 2020

The present work describes a new time marching procedure for structural dynamics analyses. In this novel technique, time integration parameters are automatically evaluated according to the properties of the model. Such parameters are locally defined, allowing the user to input a numerical dissipation property for each element, which defines the amount of numerical dissipation to be introduced. Since the integration parameters are locally defined as a function of the structural element itself, the time marching technique adapts according to the model, providing enhanced accuracy. The new methodology is based on displacement-velocity relations and no computation of accelerations is required. Furthermore, the method is second order accurate, it has guaranteed stability, it is truly self-starting and it allows highly controllable algorithm dissipation in the higher modes. Numerical results are presented and compared to those provided by the Newmark and the Bathe methods, illustrating the good performance of the new time marching procedure.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.321-322
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• 2006

In many manufacturing processes such as web formation, manufacturing of paper and nonwoven, fabric weaving, etc., planar sheets are transported and at the same time appropriate tension is imposed. The input material rolled up on beams is fed by unwinding the beam and the processed is then taken up on beams by winding it. While processed, the planar sheets are thrown under the processing load of impulse form, which causes irregular thickness of the processed sheet. To improve the quality of the product, a dynamic model is needed and the dynamic characteristics is to be analyzed by simulation. This study shows that density variation dynamics of the in-process-sheet in the machine direction can be described at each moment of disturbing impacts in forms of difference equations, while the impacts and tension, the time-dependency of the material properties were taken into account. Simulation showed the most serious variation of the density occurred in the process starting phase. The starting velocity curve with step form showed the least variation of the density. As the time order of the function of the starting velocity cure becomes higher, the density variation gets greater.

• 한국산학기술학회논문지
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• 제20권2호
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• pp.655-661
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• 2019

본 연구는 차량용 리어 디퓨저의 시작 위치에 따른 주행 성능 변화를 분석하고자 하였다. 이를 위해 CATIA 3D 설계 프로그램을 이용하여 상용 SUV 차량을 참고하여 차량을 모델링하고 뒤 타이어를 기준으로 300, 400, 500 mm 떨어진 위치부터 리어 디퓨저가 시작되도록 설계했다. 그리고 유동 해석 프로그램인 Fluent를 이용해 차량 주행속도가 60km/h, 100km/h, 140km/h 일 경우를 조건으로 하여 유동해석 후 양력과 항력의 변화를 분석하고 공기의 유선 변화를 확인했다. 해석 결과, 리어 디퓨저는 시작 위치에 상관없이 디퓨저가 없는 경우에 비해 양력과 항력을 감소시켰다. 이는 리어 디퓨저가 있을 경우 공기가 차량 하면부를 지나 후면부로 빠져나올 때 발생하는 박리 현상을 억제하여 와류 현상을 감소시키기 때문이다. 또한 본 연구에서는 SP 400의 조건일 때 양력이 가장 작았고 양력 감소 효과도 가장 좋았기 때문에 주행 중 타이어의 접지력을 최대로 확보할 수 있어서 이 경우를 최적의 조건으로 결정하였다.