• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 1999년도 학술발표회 진행표 및 논문초록
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• pp.40-40
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• 1999

We propose a method where interaction energies and force components are calculated separately for each residue of biomolecules. It is found that the correlation factors obtained from the analysis of five types of force terms and one interaction energy term (main chain self-energy) can be used to predict a mutants free energy difference relative to wild type.(omitted)

• Natural Product Sciences
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• 제25권2호
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• pp.165-171
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• 2019

Although the functions of a standardized extract of Gingko biloba leaves (EGb $761^{(R)}$) has been reported with regard to neurobiological properties, no attention has been paid to the impact of EGb $761^{(R)}$ on the neuronal regulation of energy homeostasis. To evaluate the hypothesis that EGb $761^{(R)}$ affect the secretion of peptide tyrosine tyrosine (PYY) and the activation of free fatty acid receptor 4 (FFA4), which are involved in the neuronal circuitries that control energy homeostasis by inducing the transfer of information about the influx of energy to the brain, we examined whether EGb $761^{(R)}$ can stimulate PYY secretion in the enteroendocrine NCI-H716 cells and if EGb $761^{(R)}$ can activate FFA4 in FFA4-expressing cells. In NCI-H716 cells, EGb $761^{(R)}$ stimulated PYY secretion and the EGb $761^{(R)}$-induced PYY secretion was involved in the increase in intracellular $Ca^{2+}$ concentration and the activation of FFA4. Furthermore, in FFA4-expressing cells, EGb $761^{(R)}$ activated FFA4. These results suggest that EGb $761^{(R)}$ may affect the control of energy homeostasis via the regulation of PYY secretion and FFA4 activation.

• 소음진동
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• 제6권6호
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• pp.801-818
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• 1996

Free vibration analyses of circular cylindrical shells attached with plate structures for the symmetric boundary condition such as simply-simply supported shells by receptance method are found in literatures. However analyses of those shells with unsymmetric boundary condition as clamped free boundary are hardly found. Here frequency equation of the clamped free circular cylindrical shell with end plate is derived using receptance method and natural frequencies of the combined system were calculated. The frequencies and mode shapes obtained from present method are compared with those of ANSYS to show the validity of the method. Natural frequencies and mode component ratios of clamped-free cylindrical shell are obtained by employing Rayleigh-Ritz method on energy equations, and they are used in receptance calculation. Results show good agreement with those of ANSYS analyses.

• 분석과 대안
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• 제5권2호
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• pp.77-105
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• 2021

Потребление природного газа в Азии растет быстрыми темпами из-за различных факторов, таких как экономический рост в регионе, урбанизация, переход с угля на газ в секторах производства электроэнергии и промышленности. Из-за географических особенностей и отсутствия международных трубопроводных соединений между странами в АТР большая часть природного газа, экспортируемого азиатским потребителям, транспортируется танкерами по морю в виде сжиженного природного газа. Поскольку азиатский рынок является наиболее прибыльным рынком с самым быстрым ростом спроса, конкуренция между продавцами сжиженного природного газа (СПГ) за долю азиатского рынка усиливается. Конкуренция ускорилась, особенно после того, как на рынок были выведены большие объемы дополнительных поставок со стороны новых экспортеров из США, Австралии и России. Cheniere Energy, первый экспортер СПГ в континентальной части США, не приняла традиционный механизм ценообразования и бизнес-модель. Традиционно цены по долгосрочным контрактам на СПГ индексируются к ценам на конкурирующие виды топлива, такие как сырая нефть. Компания приняла механизм ценообразования и бизнесмодель по системе «кост-плюс». Cheniere Energy выбрала более безопасную и безрисковую систему ценообразования, которая ежегодно гарантирует продавцу фиксированную сумму дохода. Компания зарабатывает одинаковую сумму денег, независимо от динамики цен на природный газ на внутреннем и международном рынке, возможно с меньшим доходом. Однако, успешно внедрив более безопасную и безрисковую бизнес-модель, Cheniere Energy, компания относительно меньшего размера по сравнению с крупными нефтегазовыми компаниями, стала примером для других небольших компаний в стране. Бизнес-модель компании продемонстрировала, как войти и управлять бизнесом СПГ в США в условиях растущей конкуренции между продавцами на внутреннем и международном рынке.

• 대한기계학회논문집B
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• 제37권12호
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• pp.1167-1173
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• 2013

본 연구에서는 천연가스 유량 측정에서 2차 표준으로 사용되는 소닉노즐 뱅크 -12개 노즐 패키지로 구성-의 임계유동함수 계산 시간을 1초 이하로 단축하고자 하였다. 이를 위해 AGA 8-dc 상태방정식을 적용한 헬름홀츠 자유에너지를 유도하고 이로부터 적분 항이 없는 열역학 상태량 식을 도출하여 CFF 계산에 적용하였다. 그 결과 CFF 계산 시간이 기존 6.7초/12개에서 0.6초/12개로 크게 감소하는 것을 확인할 수 있었고 이 계산 시간은 가스 성분 수와 거의 무관함도 알 수 있었다. 또한 본 계산 결과의 정확도를 확인하기 위해 기존 CFF 국제비교연구의 결과와 비교한 결과 차이가 없음도 확인하였다.

• 한국전산구조공학회논문집
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• 제19권3호
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• pp.313-322
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• 2006

구조물의 진동 자료를 이용하는 유전알고리즘(GA) 기반 손상검색기법에 있어, 사용되는 모드 특징의 선택은 손상검색 결과의 정확도를 높이는데 중요하다. 본 연구의 목적은 고유진동수와 모드변형에너지를 이용하여 손상검색의 정확도를 높이는 것이다. 이와 같은 연구 목적을 달성하기 위하여 다음과 같은 연구를 수행하였다. 먼저, 모드 변형에너지를 유도하고 고유진동수와 모드변형에너지를 이용하는 새로운 GA 기반 손상검색기법을 제안하였다. 다음으로 제안된 기법의 효율성을 검증하기 위하여 양단 자유보의 손상시나리오를 제시하고, 손상시나리오에 따른 진동모드 실험을 실시하였다. 마지막으로 실험 자료를 바탕으로 제안된 기법과 기존의 고유진동수와 모드형상을 이용하는 기법으로 손상검색을 실시하여 결과를 비교하였다.

• Ocean Systems Engineering
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• 제11권1호
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• pp.59-81
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• 2021

The nonlinear formulation using the principle of virtual work-energy for free vibration of a large-sag extensible catenary riser in two dimensions is presented in this paper. A support at one end is hinged and the other is a free-sliding roller in the horizontal direction. The catenary riser has a large-sag configuration in the static equilibrium state and is assumed to displace with large amplitude to the motion state. The total virtual work of the catenary riser system involves the virtual strain energy due to bending, the virtual strain energy due to axial deformation, the virtual work done by the effective weight, and the inertia forces. The nonlinear equations of motion for two-dimensional free vibration in the Cartesian coordinate system is developed based on the difference between the Euler's equations in the static state and the displaced state. The linear and nonlinear stiffness matrices of the catenary riser are obtained and the eigenvalue problem is solved using the Galerkin finite element procedure. The natural frequencies and mode shapes are obtained. The results are validated with regard to the reference research addressing the accuracy and efficiency of the proposed nonlinear formulation. The numerical results for free vibration and the effect of the nonlinear behavior for catenary riser are presented.

• 통합자연과학논문집
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• 제5권4호
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• pp.216-219
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• 2012

Structure-based drug design possibly benefit from in silico methods that precisely predict the binding affinity of small molecules to target macromolecules. There are many limitations arise from the difficulty of predicting the binding affinity of a small molecule to a biological target with the current scoring functions. There is thus a strong interest in novel methodologies based on MD simulations that claim predictions of greater accuracy than current scoring functions, helpful for a regular use designed for drug discovery in the pharmaceutical industry. Herein, we report a short review on free energy calculations using MMPBSA method a useful method in structure based drug discovery.

• Bulletin of the Korean Chemical Society
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• 제4권3호
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• pp.133-139
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• 1983

To understand the importance of Y-base adjacent to the anticodon stabilizing codon-anticodon interaction, a study has been undertaken for the model compound involving the interaction between Y-base and anticodon as well as the participation of water molecule by calculating the conformational free energy using an empirical potential function. We restrict our analysis to sites directly associated with Y-base by varying only the backbone torsion angles of Y-base. The hydration and $Mg^{+2}$ binding effects on the conformational stability of Y-base are calculated and discussed. The free Y-base is proved to be less stable than the hydrated one. The free energy change due to the hydration of Y-base amounts to -119.5 kcal/mole, in which the conformational energy change is -142.4 kcal/mole and the configurational entropy change is -76.9 e. u. It is found that the water molecules bound to Y-base and $Mg^{+2}$ contribute to the conformation of Y-base dominantly.

• Bulletin of the Korean Chemical Society
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• 제11권5호
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• pp.438-446
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• 1990

In order to elucidate conformational properties of bilayer semiflexible amphiphile molecules, we derive a expression of free energy separation with respect to bilayer width, and segment density profiles on the basis of cubic lattice model. Our result shows that at the moderate surface coverage region (i.e., ${\sigma}$ < 0.35), bilayer system tends to have thermodynamically favorable bilayer width corresponding to free energy minimum condition resulting from the major contribution of attractive interaction between chain segments. However such a favorable bilayer width do not occur in the region of high surface converage (i.e., ${\sigma}$> 0.4) where repulsive interaction between chain segments is considered to be dominant.