• Journal of Acupuncture Research
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• 제21권6호
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• pp.233-248
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• 2004

Objective : The purpose of this study is to investigate the mechanism and effect of moxibustion with monkshood cake, slice & black pepper cake. objectively, to be used as the quantitative data through the measurement of temperatqre, and to grasp the thermodynamic characteristics of moxibustion with monkshood cake, slice & black pepper cake. Methods : We have selected of the moxibustion with monkshood cake, slice & black pepper cake. indirect moxibustion. We make a comparative study of the thermodynamic characteristics of moxibustion with monkshood cake, slice & black pepper cake. We examined combustion times, temperatures, temperature gradients in each period during a combustion of moxa. Results & Conclusions : 1. We can design the moxibustion with monkshood cake that it has thermodynamic characteristics of 173sec effective combustion time, $44^{\circ}C$ maximum temperature, $0.22^{\circ}C/sec$ ascending maximum temperature, if we use 3mm thickness or 3mm and below of monkshood cake and the moxa cone is formed the conical shape that the base diameter was 8mm, the height was 10mm, the density was $600mg/cm^3$. 2. We can design the moxibustion with monkshood cake that it has thermodynamic characteristics of 205~271sec effective combustion period time, $44.6{\sim}46.1^{\circ}C$ maximum temperature, $0.18{\sim}0.24^{\circ}C/sec$ ascending maximum temperature, if we use 3mm thickness of monkshood cake and the moxa cone is formed the conical shape that the base diameter was 8mm, the height was 10mm, the density was $480{\sim}720mg/cm^3$.

• 한국세라믹학회지
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• 제48권3호
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• pp.236-240
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• 2011

In order to deposit a homogeneous and uniform ${\beta}$-SiC films by chemical vapor deposition, we demonstrated the phase stability of ${\beta}$-SiC over graphite and silicon via computational thermodynamic calculation considering pressure, temperature and gas composition as variables. The ${\beta}$-SiC predominant region over other solid phases like carbon and silicon was changed gradually and consistently with temperature and pressure. Practically these maps provide necessary conditions for homogeneous ${\beta}$-SiC deposition of single phase. With the thermodynamic analyses, the CVD apparatus for uniform coating was modeled and simulated with computational fluid dynamics to obtain temperature and flow distribution in the CVD chamber. It gave an inspiration for the uniform temperature distribution and low local flow velocity over the deposition chamber. These calculation and model simulation could provide milestones for improving the thickness uniformity and phase homogeneity.

• 대한화학회지
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• 제37권4호
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• pp.442-447
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• 1993

수용액 내에서 란탄(Ⅲ)-benzoylformate 착물 형성 반응의 열역학적 파라메타들(${\Delta}$G, ${\Delta}$H 및 ${\Delta}$S)을 pH 및 엔탈피 적정 방법을 사용하여 이온세기 $0.1M NaClO_4$, 25$^{\circ}C$ 조건하에서 구하였다. 란탄-benzoylformate 착물의 안정도 상수(1:1) 값으로부터 benzoylformate가 두자리 리간드로 작용함을 알 수 있었다. 열역학적 실험 결과는 카르복실기와 함께 케톤기 산소원자가 결합에 참여하여 킬레이트를형성하는 것으로 판단되었으며, 이는 benzoylformate 리간드 내에 존재하는 벤젠고리의 공액 효과에 의해 케톤기의 산소원자의 전하량이 증가된 결과로 해석되었다. 착물의 안정도는 엔트로피 효과 뿐 아니라, 금속-산소결합 형성에 따른 엔탈피 효과에도 기인하였다.

• Corrosion Science and Technology
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• 제3권5호
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• pp.198-208
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• 2004

Although there has been no general agreement on the mechanism of primary water stress corrosion cracking (PWSCC) as one of major degradation modes of Ni-base alloys in pressurized water reactors (PWR's), common postulation derived from previous studies is that the damage to the alloy substrate can be related to mass transport characteristics and/or repair properties of overlaid oxide film. Recently, it was shown that the oxide film structure and PWSCC initiation time as well as crack growth rate were systematically varied as a function of dissolved hydrogen concentration in high temperature water, supporting the postulation. In order to understand how the oxide film composition can vary with water chemistry, this study was conducted to characterize oxide films on Alloy 600 by an in-situ Raman spectroscopy. Based on both experimental and thermodynamic prediction results, Ni/NiO thermodynamic equilibrium condition was defined as a function of electrochemical potential and temperature. The results agree well with Attanasio et al.'s data by contact electrical resistance measurements. The anomalously high PWSCC growth rate consistently observed in the vicinity of Ni/NiO equilibrium is then attributed to weak thermodynamic stability of NiO. Redox-induced phase transition between Ni metal and NiO may undermine the integrity of NiO and enhance presumably the percolation of oxidizing environment through the oxide film, especially along grain boundaries. The redox-induced grain boundary oxide degradation mechanism has been postulated and will be tested by using the in-situ Raman facility.

• 자원리싸이클링
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• 제26권5호
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• pp.85-96
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• 2017

본 연구에서는 PCB 도금 및 에칭 공정 중 발생한 슬러지의 분석을 통해 건식환원처리가 가능한 슬래그 시스템을 선정하고자 하였으며 이를 바탕으로 슬러지 내에 존재하는 유가금속의 회수 가능성에 대하여 실험적 및 열역학적 검토를 하였다. 슬러지는 $100{\sim}500^{\circ}C$의 온도구간에서 건조한 후 슬러지의 형상과 화학성분 및 상을 분석하였다. 슬러지의 건식환원처리 가능성은 FactSage를 이용한 열역학적 계산을 통해 조사하였다.

• 자원리싸이클링
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• 제28권1호
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• pp.32-39
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• 2019

본 연구에서는 석고의 형태로 황산염이 혼입된 알칼리 활성 슬래그의 수화반응에 대해, 깁스 최소화 에너지 개념을 이용한 반응계산 결과가 계산 조건에 따라 어떻게 달라지는지에 대해 확인하였다. 계산을 위한 변수로는 황화물의 고려 여부, AFt/AFm 상의 생성가능성 여부, 대기 중 산소의 반응기여 여부 등을 검토하였다. 계산결과, 실제 위의 다양한 조건의 변화에도 불구하고 공극량, 화학수축과 같이 이후 배합의 성능에 영향을 미칠 수 있을 만한 값 들은 크게 차이가 발생하지 않았는데, 이 변수들에 의한 변화폭은 물결합재비에 의한 변화폭에 비해 월등히 작은 값이었다. 생성되는 물질들의 종류 및 양은 일부 초기조건 설정에 따라 변화할 수 있으나, 가장 주요한 수화물인 C-(N-)A-S-H의 생성량에는 별다른 영향을 미치지 않았다.

• 대한금속재료학회지
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• 제46권12호
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• pp.771-779
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• 2008

An effective way of increasing the strength and fracture toughness of reactor pressure vessel steels is to change the material specification from that of Mn-Mo-Ni low alloy steel(SA508 Gr.3) to Ni-Mo-Cr low alloy steel(SA508 Gr.4N). In this study, we evaluate the effects of alloying elements on the microstructural characteristics of Ni-Mo-Cr low alloy steel. The changes in the stable phase of the SA508 Gr.4N low alloy steel with alloying elements were evaluated by means of a thermodynamic calculation conducted with the software ThermoCalc. The changes were then compared with the observed microstructural results. The calculation of Ni-Mo-Cr low alloy steels confirms that the ferrite formation temperature decreases as the Ni content increases because of the austenite stabilization effect. Consequently, in the microscopic observation, the lath martensitic structure becomes finer as the Ni content increases. However, Ni does not affect the carbide phases such as $M_{23}C_6 $ and $M_7C_3$. When the Cr content decreases, the carbide phases become unstable and carbide coarsening can be observed. With an increase in the Mo content, the $M_2C$ phase becomes stable instead of the $M_7C_3$ phase. This behavior is also observed in TEM. From the calculation results and the observation results of the microstructure, the thermodynamic calculation can be used to predict the precipitation behavior.

• Steel and Composite Structures
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• 제41권6호
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• pp.873-886
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• 2021

In this paper, an analytical solution for thermodynamic response of functionally graded (FG) sandwich plates resting on variable elastic foundation is performed by using a quasi 3D shear deformation plate theory. The displacement field used in the present study contains undetermined integral terms and involves only four unknown functions with including stretching effect. The FG sandwich plate is considered to be subject to a time harmonic sinusoidal temperature field across its thickness with any combined boundary conditions. Equations of motion are derived from Hamilton's principle. The numerical results are compared with the existing results of quasi-3D shear deformation theories and an excellent agreement is observed. Several numerical examples for fundamental frequency, deflection, stress and variable elastic foundation parameter's analysis of FG sandwich plates are presented and discussed considering different material gradients, layer thickness ratios, thickness-to-length ratios and boundary conditions. The results of the present study reveal that the nature of the elastic foundation, the boundary conditions and the thermodynamic loading affect the response of the FG plate especially in the case of a thick plate.

• 전기화학회지
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• 제26권4호
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• pp.56-63
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• 2023

태양, 파도, 바람 등 친환경 재생에너지원을 이용한 전력 생산 기술이 성숙함에 따라 재생에너지 전력의 경제성과 규모 측면에서 빠르게 발전하고 있다. 특히, 전기화학적인 방법으로 수소를 생산하는 기술은 이러한 재생에너지와 효율적으로 연계될 수 있는 방법 중 하나로 주목받고 있다. 수전해 기술은 작동 온도에 따라서 저온(100 ℃ 이하), 중온(300-700 ℃), 고온(700 ℃ 이상) 수전해로 나눌 수 있으며, 에너지 소비량 및 전압 효율 평가는 열역학 법칙에 따라 계산한다. 그러나 수전해 평가에서 열역학적 전압(thermodynamic voltage)과 열중성 전압(thermo-neutral voltage)의 개념이 혼용되어 사용되고 있다. 본 총설에서는 저온 PEM (proton exchange membrane) 수전해 기술을 바탕으로 작동 전압과 효율 평가에 대한 이해를 높이고, 열역학적 전압과 열중성 전압의 차이점을 명확히 하고자 한다.

• 한국결정성장학회지
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• 제8권3호
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• pp.387-387
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• 1998

본 연구에서는 기상화학 증착법으로 성장되는 GaN 후막에 대한 열역학적 전사모사를 수행하고 이를 실험결과와 비교, 검토하였다. 열역학적계산은 화학양론적 연산방식을 이용하여 수치 해석하였으며, 모사의 변수로써 온도범위는 400∼1500K, 기상비율은 $(GaCl_3)/[GaCl_3+NH_3],(N_2)/(GaCl_3+NH_3)$를 취하였다. GaN의 성장온도 범위는 이론적인 계산이 실험결과보다 훨씬 낮은 450∼750K으로 예측되었다. 성장온도에서 모사결과와 실험결과와의 차이는 GaN의 기상 에픽텍시 성장이 박막성장의 높은 활성화 에너지 때문에 반응속도론적으로 국한된 영역 내에서 발생한다는 것을 나타낸다.