• Journal of Mechanical Science and Technology
• /
• 제18권12호
• /
• pp.2148-2157
• /
• 2004

The paper deals with the vibration and dynamic stability of cantilevered pipes conveying fluid on elastic foundations. The relationship between the eigenvalue branches and corresponding unstable modes associated with the flutter of the pipe is thoroughly investigated. Governing equations of motion are derived from the extended Hamilton's principle, and a numerical scheme using finite element methods is applied to obtain the discretized equations. The critical flow velocity and stability maps of the pipe are obtained for various elastic foundation parameters, mass ratios of the pipe, and structural damping coefficients. Especially critical mass ratios, at which the transference of the eigenvalue branches related to flutter takes place, are precisely determined. Finally, the flutter configuration of the pipe at the critical flow velocities is drawn graphically at every twelfth period to define the order of the quasi-mode of flutter configuration.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
• /
• pp.451-454
• /
• 2001

The ionic conductivity of cubic solid solutions in the system $Y_{2}O_{3}-ZrO_{2}$ prepared by SHS was examined. Conductivity-temperature data obtained at $1000^{\circ}C$ in atmosphere of low oxygen partial pressure ($10^{-40}$ atm) for $Y_{2}O_{3}-ZrO_{2}$ cubic solid solutions indicated that these materials could be reduced, the degree of reduction being related to the measuring electric field. At low impressed fields no reduction was observed. Thus, these conductivity data give a transference number for the oxygen ion in $Y_{2}O_{3}-ZrO_{2}$ cubic solid solutions greater than 0.99.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
• /
• pp.906-908
• /
• 1999

The application of ozone solid polymer electrolyte or Membrel water electrolysis cells with $PbO_2$ anodes for anodic generation of ozone in electrolyte-free water is reported. Maximum yields were obtained at a temperature of $25^{\circ}C-30^{\circ}C$ and current density of about 1A/$cm^2$. The current efficiency was not found to depend on ozone concentration in the feed water. exclusive transference of electric current by protons absence of convection in the electrolyte and high oxygen oversaturatation in the vicinity of electrode

• 한국소음진동공학회논문집
• /
• 제13권12호
• /
• pp.956-964
• /
• 2003

The paper describes the relationship between the eigenvalue branches and the corresponding flutter modes of cantilevered pipes with a tip mass conveying fluid. Governing equations of motion are derived by extended Hamilton's principle, and the numerical scheme using finite element method is applied to obtain the discretized equations. The flutter configurations of the pipes at the critical flow velocities are drawn graphically at every twelfth period to define the order of quasi-mode of flutter configuration. The critical mass ratios, at which the transference of the eigenvalue branches related to flutter takes place. are definitely determined. Also, in the case of haying internal damping, the critical tip mass ratios, at which the consistency between eigenvalue braches and quasi-modes occurs. are thoroughly obtained.

• 대한기계학회논문집A
• /
• 제27권4호
• /
• pp.499-506
• /
• 2003

The design cycle associated with large engineering systems requires an initial decomposition of the complex system into design processes which are coupled through the transference of output data. Some of these design processes may be grouped into iterative subcycles. In analyzing or optimizing such a coupled system, it is essential to determine the best order of the processes within these subcycles to reduce design cycle time and cost. This is accomplished by decomposing large multidisciplinary problems into several sub design structure matrices (DSMs) and processing them in parallel This paper proposes a new method for parallel decomposition of multidisciplinary problems to improve design efficiency by using the multi-objective genetic algorithm and two sample test cases are presented to show the effect of the suggested decomposition method.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1996년도 추계학술대회 논문집
• /
• pp.105-108
• /
• 1996

The positive active material for polymer film battery was prepared by using Polyphenylenediamine(PPD) synthesized in our lab. and 2.5-dimercapto-1, 3, 4-thiadiazole(DMcT) in various mixture ratio. The transference measurement of surface morphology and thermal stability of prepared composite film was carried out by using SEM and TGA, respectively. Electrocyhemical property and electrical conductivity of composite film were also measured by using cyclic voltammetry and four-probe method in dry box, respectively. The thermal stability of prepared composite film is more than 20$0^{\circ}C$. The electrical conductivity of composite film increased and showed the highest value(about 3 S/cm)when doped at 0.4% LiClO$_4$solution. And we could confirm that DMcT effect on reactiviation of PPD through cyclic voltammogram.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집
• /
• pp.451-454
• /
• 2001

The ionic conductivity of cubic solid solutions in the system Y$_2$O$_3$-ZrO$_2$ prepared by SHS was examined. Conductivity-temperature data obtained at 1000$^{\circ}C$ in atmosphere of low oxygen partial pressure (10$\^$-40/ atm) for Y$_2$O$_3$-ZrO$_2$ cubic solid solutions indicated that these materials could be reduced, the degree of reduction being related to the measuring electric field. At low impressed fields no reduction was observed. Thus, these conductivity data give a transference number for the oxygen ion in Y$_2$O$_3$-ZrO$_2$ cubic solid solutions greater than 0.99.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
• /
• pp.508-509
• /
• 2005

In case of ITO/MEH-PPV/Al structure, the quantity of charge carriers flowing through the organic material was few and the density of them is fixed. The electric field inside of the device almost didn't change with the position. On the other hands, in case of Au/MEH-PPV/Au structure, the hole density increased rapidly nearby the anode but decreased nearby the cathode. The space charge phenomenon followed sufficient hole injection resulted in the change of the electric field with the position inside of the device. We verified that the result of the current-voltage simulation corresponded with experimental result.

• Korean Journal of Chemical Engineering
• /
• 제35권12호
• /
• pp.2464-2467
• /
• 2018

Organic batteries are attractive alternatives to conventional inorganic batteries because of their low cost, biodegradation, and renewability, and their consequent environmental friendliness. We investigated the influence of carbon conductors and electrolytes in organic batteries using dilithium terephthalate ($Li_2C_8H_4O_4$). The synthesized dilithium terephthalate has well-grown crystallinity and non-uniform shaped particles without impurities. The dilithium terephthalate-based battery shows good electrochemical properties with a LiTFSI/TEGDME electrolyte and graphene as the carbon conductor in an organic electrode. The results are ascribed to the high lithium transference number of LiTFSI/TEGDME and the high electrical conductivity of graphene.

• 국제학술발표논문집
• /
• The 1th International Conference on Construction Engineering and Project Management
• /
• pp.1187-1192
• /
• 2005

Approximately 25% of military establishments became superannuated to unable perform their function, and it influences on the environment by construction wastes and the waste of national budget, as there is no rational and objective standard even though old facilities have been replaced through modernization project. Therefore, it has been searched to introduce industrial building system that can cope with the new building-construction and transference for the improvement of existing military establishments. However, as there is no economical estimation standard for practical use, industrial building-construction is still remaining at the initial stage, and the study is insufficient too. So. in this study, I would like to develope LCC cost model for rational LCC comparative analysis between industrial construction system (Modular) and existing reinforced concrete structure and cage, and to evaluate economical efficiency through case analysis.