• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1049-1056
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• 2023

The height of the atmospheric boundary layer indicates the peak developed when turbulence is generated by mixing heat and water vapor, and is generally determined through thermodynamic methods. Wind profilers produce atmospheric information from the scattering of signals sent into the atmosphere. A method for making the spectrum of turbulent components, turbulent kinetic energy dissipation rate, and refractive index structure coefficient was presented to determine the atmospheric boundary layer depth. Compared with the vertical distribution characteristics of potential temperature and specific humidity based on radiosonde data, the determination method of the atmospheric boundary layer height from wind profiler output was evaluated as very useful.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.751-759
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• 1994

Concrete contains numerous microcracks initially. The growth and propagation of microcracks cause failure of concrete. These processings are termed as "damage". The concepts of the continuum damage mechanics are presented and the damage evolution law and constitutive equation are derived by using the Helmholz free energy and the dissipation potential by means of the thermodynamic principles. The constitutive equation includes the effects of elasticity, damage and plasticity of concrete. The proposed model successfully predicts the nonlinear behavior of concrete subject to monotonic uniaxial and biaxial loadings.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.2
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• pp.33-38
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• 2004

We have demonstrated a tunable Inter based on an asymmetric directional coupler made of a side-polished polarization maintaining fiber coupled with a polymer planar waveguide. The thermo-optic effects of the polymer planar waveguide induced by a micro-strip heater placed on the top layer of the device leads to shift of resonance wavelength of the coupler. The fabricated device exhibited wide tunable range exceeding 230 nm with 720 ㎽ of applied electrical power.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.2
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• pp.275-284
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• 1997

Thermodynamic behavior of a composite system which is composed of two simple thermal subsystems with constant heat capacities is analyzed, and several thermodynamic phenomena are investigated. The changes of the states and the potential work of the composite system are shown as the interaction between the subsystems in the composite system. The potential work is defined as the possible maximum available work from the composite system, and it is a thermodynamic property of the composite system. The decrease of the potential work is the same as the available work output from the composite system in reversible processes. The dissipation of available work is directly connected to the generation of entropy. The concepts of exergy and internal energy can be explained as a special case of the potential work.

• Journal of Korean Medical classics
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• v.18 no.4 s.31
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• pp.44-48
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• 2005

소위(所謂) 심풍열증시상화치성이혈조(心風熱證是相火熾盛而血操), 인기음수다(引起飮水多), 습열울체어혈분적결흉병(濕熱鬱滯於血分的結胸病). 인이(因而), 흉중수기불능하강(胸中水氣不能下降), 유차가견류사소양병적결흉증상(由此可見類似少陽病的結胸證象), 이차재체표용역조성잉유부진소산적풍열사(而且在體表容易造成仍有不盡消散的風濕邪). 여차병황하(如此病況下), 심장지열영향소장이출현(心臟之熱影向小腸而出現), 뇨수빈이부창(尿雖頻而不暢), 혹뇨량소이소편불리(或尿量少而小便不利). 종상소술(綜上所述), 여하요약기내용(如下要略其內容). 1. 도적강기탕시적합용어소양인소양병습열결흉(導赤降氣湯是適合用於少陽人少陽病濕熱結胸). 2. 기병증수속어혈분증(其病證雖屬於血分證), 인잉유표증(因仍有表證), 고의겸용발산지제(故宜兼用發散之齊). 3. 여겸유안양등(如兼有眼痒等) 간담병증(肝膽病證), 환령가기타처방. 4. 해방대소화계통허약(該方對消化系統虛弱), 겸유수족냉(兼有手足冷), 훈차(暈車), 전두통(前頭痛), 장염(腸炎) 등적환아(等的患兒), 기효과흠가(其效果欠佳). 5. 유차가지(由此可知), 도적강기탕시침대심유습열(導赤降氣湯是針對心有濕熱), 위야유열(胃也有熱), 잉유표증(仍有表證), 부겸유간담병증적환아료효호(不兼有肝膽病證的患兒療效好). 여유소시호탕증(如有小柴胡湯證), 즉선용시호지제이해제해증(則先用柴胡之劑而解除該證), 연후재변증(然後再辨證), 재산시해치법적원칙(才算是該治法的原則).

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.1
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• pp.87-92
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• 2016

Van der Pol's oscillators is non-conservative oscillator that having nonlinear damping phenomena. The energy of its system is dissipative at a high amplitude whereas its system creates the energy at low amplitude. In order to identify another behaviors in the Van der Pol oscillator, the periodic external force applied in the Van der Pol oscillator. This paper confirms the pattern of variation for the limit cycle according to parameter variation in order to identify another behaviors in the Van der Pol oscillator.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.12
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• pp.3991-4002
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• 1996

Thermally fully developed and thermally developing laminar flows of a Bingham plastic in a circular pipe have been studied analytically. For thermally fully developed flow, the Nusselt numbers and temperature profiles are presented in terms of the yield stress and Peclet number, proposing a correlation formula between the Nusselt number and the Peclet number. The solution to the Graetz problem has been obtained by using the method of separation of variables, where the resulting eigenvalue problem is solved approximately by using the method of weighted residuals. The effects of the yield stress, Peclet and Brinkman numbers on the Nusselt number are discussed.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.4
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• pp.489-498
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• 1988

An analysis has been given for the effect of viscous dissipation on the thermal instability of plane Couette flow between two parallel plates maintained at different constant temperatures. Under the assumption that the principle of the exchange of stabilities holds, stationary disturbance quantities in the form of longitudinal vortices are considered. The magnitudes of disturbance quantities are then represented as fast convergent power series so that the eigenvalue problem for determining the onset conditions of the thermal instability may be reduced to a simplified problem of finding the roots of a $4{\times}4$ determinant. It is shown that as the magnitude of the visucous dissipation increases the flow becomes more susceptible to instabilities, which is in very good agreement with previous results obtained in some related researches.

• Journal of the Korea Concrete Institute
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• v.15 no.1
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• pp.17-24
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• 2003

One of the reasons for brittle failure in reinforced concrete structures subjected to severe earthquake is due to large local bond-slippage of bars resulting in fast bond degradation between reinforcing bars and concrete. This study aims to evaluate effects of bar deformation height on bond performance, specially, bond degradation under cyclic loading. Bond test specimens were constructed with machined bars with high relative rib areas. The degree of confinement by transverse bars is also another key parameters in this bond test. From test results, amounts of energy dissipation are calculated and compared for each parameter. Test results show that bond strength and stiffness drops significantly as cycles increases. The confinement and high relative rib area are effective to delay bond degradation, as the reduction of bond strength of cyclic loading compared to monotonic loading decreased for bars with large confinement and high relative rib areas. The energy dissipation also increases as the degree of confinement and relative rib area increases. However, tested bars with very high rib areas show that the bond may be damaged at relatively small slip because of high stiffness. The study will help to understand the bond degradation mechanism due to bar deformation height under cyclic loading and be useful to develop new deformed bars with high relative rib areas.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.6
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• pp.409-414
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• 2017

The aim of this study is to understand the phonon transfer characteristics of a silicon thin film transistor. For this purpose, the Joule heating mechanism was considered through the electron-phonon interaction model whose validation has been done. The phonon transport characteristics were investigated in terms of phonon mean free path for the variations in the device power and silicon layer thickness from 41 nm to 177 nm. The results may be used for developing the thermal design strategy for achieving reliability and efficiency of the silicon-on-insulator (SOI) transistor, further, they will increase the understanding of heat conduction in SOI systems, which are very important in the semiconductor industry and the nano-fabrication technology.