• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.157-164
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• 2008

The temperature-entropy diagram of water or vapor displays graphically the thermophysical properties, so it is very conveniently used in various thermal systems. On general T-s chart of water, there are temperature, pressure, quality, specific volume, specific enthalpy, specific entropy. However, various state and process values besides above properties can be plotted on T-s diagram. In this study, we developed the software drawing twenty six kinds of properties, that is temperature, pressure, quality, specific volume, specific internal energy, specific enthalpy, specific entropy, specific exergy, exergy ratio, density, isobaric specific heat, isochoric specific heat, ratio of specific heat, coefficient of viscosity, kinematic coefficient of viscosity, thermal conductivity, prandtl number, ion product, static dielectric constant, isentropic exponent, velocity of sound, joule-thomson coefficient, pressure coefficient, volumetric coefficient of expansion, isentropic compressibility, and isothermal compressibility. Also, this software can analyze and print the system values of mass flow rate, volume flow rate, internal energy flow rate, enthalpy flow rate, entropy flow rate, exergy flow rate, heat flow rate, power output, power efficiency, and reversible work. Additionally, this software support the functions such as MS-Power Point.

• Computers and Concrete
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• 제11권6호
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• pp.515-529
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• 2013

The moment-curvature relation for simple bending is a well-studied subject and the classical moment-curvature diagram is commonly found in literature. The influence of axial forces has generally been considered as compression onto symmetrically reinforced cross-sections, thus strain at the reference fiber never has been an issue. However, when dealing with integral structures, which are usually statically indeterminate in different degrees, these concepts are not sufficient. Their horizontal elements are often completely restrained, which, under imposed deformations, leads to moderate compressive or tensile axial forces. The authors propose to analyze conventional beam cross-sections with moment-curvature diagrams considering asymmetrically reinforced cross-sections under combined influence of bending and moderate axial force. In addition a new diagram is introduced that expands the common moment-curvature relation onto the strain variation at the reference fiber. A parametric study presented in this article reveals the significant influence of selected cross-section parameters.

• Journal of Advanced Marine Engineering and Technology
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• 제38권2호
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• pp.208-216
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• 2014

In case of any coastal ocean near the mouth of huge rivers, low salinity water can be formed due to its large amount of freshwater discharge. For the acoustic analysis on the low salinity environment, some oceanographic data of the East China Sea and the Atlantic Ocean were collected through KODC (Korea Oceanographic Data Center) and NODC (National Oceanographic Data Center) online service. In this paper, the T-S gradient diagram is introduced to show a relation between the gradients of temperature and salinity in view of acoustic surface channel formation. Existence of haline channel, quantitative contribution of gradients of salinity and temperature, effectiveness of the channel formation can be known by the T-S gradient diagram. After applying the collected data into the diagram, tropical regions of the Atlantic Ocean show strong haline channel due to its nearly invariant temperature and drastic change of salinity with depth. The averaged transmission loss in the channel is about 5.7 ~ 7.5 dB less than that out of the channel by the results of acoustic propagation model (RAM: Range independent Acoustic Model). On the other hand, the East China Sea and temperate region of the Atlantic ocean have weaker haline channel with less difference of the averaged transmission loss between in and out of the channel as 3.2 ~ 6.0 dB. Although data samples used in this study have limitation to represent the general physical structures of the three ocean regions, the T-S gradient diagram is shown to be useful and acoustic field affected by low salinity environment is investigated in this study.

• 한국실내디자인학회논문집
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• 제15권4호
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• pp.147-155
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• 2006

Recently, because of the rapid remarkable development of the digital media, contemporary society is continuously extending and changing over the limitation of the human recognition. But in the field of architectural form creation, a diagram used in the design process of the past is not enough to reflect a complication, contingent and multiple quality of these contemporary society. So, to reveal the rhizomorphous and non-hierarchial qualify of the contemporary digital network society, architecture became necessary to use the diagram with digital media which have various possibilities to present architect's abstract images that the diagram of the past couldn't do. Therefore, this study proposes that the process for creating architectural form with the digital diagram be a alternative to conquest the limits of contemporary architecture, so it present the complicate and contingent quality of contemporary society. Furthermore, it examines the quality and possibility of the diagram by understanding the creation and transformation of the digital diagram, and how to apply to the actual architecture process of the creating form.

• 동력기계공학회지
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• 제9권4호
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• pp.83-89
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• 2005

Molding shrinkage is one of the problems to be solved in conventional injection molding. Despite many trying-out has been to solve it, intrinsic cause of shrinkage such as orientation and thermal exchange between melt and mold has not been solved yet. For reducing shrinkage and residual stress on molding, injection compression molding process was invented. In this study, experiments about effects of injection compression molding's parameters on shrinkage of PMMA molding were conducted and compared with conventional injection molding's shrinkage. Before the injection compression molding experiment, molding shrinkage rate was predicted by analyzing pvT diagram and was compared with the results of experiment. The shrinkage rate of injection compression molding was lower than convention injection molding's one which was different from the predicted shrinkage. The reason was observed that the experimental mold was not a proper type for injection compression, flowing backward of melt into nozzle and unreasonable mechanism of injection molding machine.

• 대한수학회지
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• 제32권4호
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• pp.725-737
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• 1995

Let $X_t = (X_t^(1), X_t^(2))', t \geqslant 0$, be a real stationary 2-dimensional Gaussian process with $EX_t^(1) = EX_t^(2) = 0$ and $$ EX_0 X'_t = (_{\rho(t) r(t)}^{r(t) \rho(t)}), $$ where $r(t) \sim $\mid$t$\mid$^-\alpha, 0 < \alpha < 1/2, \rho(t) = o(r(t)) as t \to \infty, r(0) = 1, and \rho(0) = \rho (0 \leqslant \rho < 1)$. For $t > 0, u > 0, and \upsilon > 0, let L_t (u, \upsilon)$ be the time spent by $X_s, 0 \leqslant s \leqslant t$, above the level $(u, \upsilon)$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1804-1806
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• 1997

Route conditions, applied voltage and the condition of stringing conductors should be considered in determining standard types and skeleton diagrams of towers. In skeleton diagrams the necessary number of insulators and the air clearance have been decided by the results of studies on insulation coordination. Galloping, sleet-jumping, sag characteristics and the possibility of closeness of conductors should be considered according to the condition of stringing conductor and the span. After reviewing those factors, it is necessary to determine the minimum vertical and horizontal distance for the safety of transmission lines under any circumstances. Also it should be economical.

• 설비공학논문집
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• 제2권3호
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• pp.218-225
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• 1990

Studies on the performance of a heat pump using non-azeotropic refrigerant mixtures are done. In order to estimate the thermodynamic properties for the selected non-azeotropic refrigerant mixtures including R22/R152a, R22/R142b, R22/R114 and R13B1/R152a, Peng-Robinson equation of state is adopted. The pressure-enthalpy diagram and the temperature-entropy diagram are plotted for each refrigerant mixture. Considerations on the capacity modulation for the heat pump system using refrigerant mixtures are taken into. Results show that when the heating load varies, the possibility for the capacity modulation is found in the heat pump system using a compressor with constant volume flow rate. Under a constant heating capacity condition in the heat pump system, the coefficient of performance increases when the refrigerant mixtures are used. The volume flow rate decreases as the mass fraction of lower boiler increases in this case.

• 한국해양학회지
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• 제25권1호
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• pp.1-7
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• 1990

동해 서남해역의 상부 125미터 수층을 대상으로 1981년 9월부터 1984년 10월에 걸 쳐 6회의 현장조사를 실시하여 841개의 해수시료를 구하였고, 이들의 수온, 염분, 무 기영향염류 및 식물플랑크톤 종별 현존량에 대하여 연구하였다. 도합 235종류의 식물플랑크톤을 동정하였으며, 이 가운데 Cylindrothecqa closterium 과 Nitzschia delicatissuma 등의 두 종이 최고의 공통종인 동시에 우점종으로 나타났다. 연구해역 상부혼합 층 시료 중의 식물플랑크톤 현존량과 수온, 염분 및 무기영양염류 등의 환경 요인과의 관계를 다중회귀 분석한 결과 봄에는 수온의 회귀상수가 염분에 비해 1.6-4.2배 컸으며, 반대로 가을에는 염분의 회귀상수가 수온에 비해 2.1-3.4배 크게 나타났다. T-S diagram 위에서 식물플랑크톤 현존량 분포가 봄에는 수온 변화에 민감 하였으며 가을에는 염분 변화에 민감하였고, 도식적으로 T-S diagram 상에 표시한 높 은 현존량 구역은 계절적으로 순환하는 양상을 나타내었다. 이는 연구해역의 식물플랑 크톤 현존량 분포가 여타가 여타의 환경요인보다 특별히 해양물리학적 특성과 긴밀한 관계가 있음을 의미한다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.258-261
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• 2007

Failure phenomena in uni-axial tension test were experimentally and numerically investigated for AA6111-T4, AA5083-H18 and DP-Steel, which were friction-stir welded with the same and different thicknesses. Forming limit diagram(FLD) was measured using hemispherical dome stretching tests for base materials and also predicted by Hill's bifurcation and M-K theories for welded areas. Finite element simulations well predicted hardening behaviors, failure locations as well as failure patterns for the uni-axial tension tests especially utilizing very fine meshes and FLD along with stress softening.