• 전자공학회논문지C
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• 제34C권8호
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• pp.64-70
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• 1997

This paper presents a parameter optimization method using evolutionary programming in voltage reference circuit because the designer must select appropriate parameter values of the circuit taking into consideration both powr voltage and temperature variation. In this paper, evolutionary programming is suggested as an approach for finding good parameters with which the reference voltage variation is small with respect to temperature variation. Simulation results. Simulation results show that this method is effective in circuit design.

• 대한설비공학회지:설비저널
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• 제4권1호
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• pp.6-17
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• 1975

For a periodic variation of the flue gas temperature the heat conduction through the Ondol floor was analysized. Also the heat loss to the ground was estimated. The floor thermal capacity, as a function of the floor thickness, has strong influence on the time lag of the temperature variation. It is an important design parameter for intermittent heating. Even for the steady periodic variation, there was significant heat loss to the ground below the Ondol floor.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.309-313
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• 1997

(Ba$_{x}$Sr$_{l-x}$)TiO$_3$(BST) thin fi1ms with various Ba/Sr ratios were deposited on Pt(80nm)/SiO$_2$(100nm)/Si by RF magnetron sputtering. BST thin films which have x=0.6, 0.5, 0.4 were studied dielectric properties with temperature variation. The frequency was used from 100Hz to 1MHz for measuring dielectric constant. The measurement conditions of dielectric constant with Temperature Variation were 1KHz and 2$0^{\circ}C$. As a result, the dielectric constant of BST thin film was about 425 and loss factor was 0.013. Also, with increasing Temperature, the dielectric constants of BST thin films were gradually decreased.sed.

• 천문학논총
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• 제5권1호
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• pp.65-84
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• 1990

The temperature effects of the KNU UBV photometric system are investigated, using the HAMAMATSU 1P21 data. The variation of the passband width of V-band with temperature is about $5{\AA}/^{\circ}C$ while those of B-band and U-band are negligible. This large effect of V-band causes a significant variation of V-mag. and (B-V)-color with temperature such as ${\sim}0.02mag/^{\circ}C$ in both cases. This result strongly suggests that in the photometric observations of binary stars, the temperature effects of the response of photomultiplier and the passband of filters must be considered to avoid the systematic variation in magnitude and color particularly at the minimum of light curve.

• Journal of Mechanical Science and Technology
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• 제19권4호
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• pp.958-967
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• 2005

The mathematical model for tension behaviors of a moving web by Shin (2000) is extended to the tension model considering the thermal strain due to temperature variation in furnace. The extended model includes the terms that take into account the effect of the change of the Young's Modulus, the thermal coefficient, and the thermal strain on the variation of strip tension. Computer simulation study proved that the extended tension model could be used to analyze tension behaviors even when the strip goes through temperature variation. By using the extended tension model, a new tension control method is suggested in this paper. The key factors of suggested tension control method include that the thermal strain of strip could be compensated by using the velocity adjustment of the helper-rollers. The computer simulation was carried out to confirm the performance of the suggested tension control method. Simulation results show that the suggested tension control logic not only overcomes the problem of the traditional tension control logic, but also improves the performance of tension control in a furnace of the CAL (Continuous Annealing Line).

• 소성∙가공
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• 제16권1호
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• pp.36-41
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• 2007

Thermoplastic elastomer(TPE) can be recycled and molded such as commercial thermoplastic. Therefore TPE has being widely applied on automobile, household and etc. in these days. This study shows the variation of mechanical properties and shrinkage on TPE moldings for variation of injection molding conditions such as injection pressure, holding pressure, melt temperature, mold temperature and etc. Mechanical properties in relation to tensile strength, hardness and shrinkage in connection with precision dimension of part are investigated. The tensile strength and shrinkage of the experimental TPEs are mainly influenced by injection pressure and melt temperature. All injection molding conditions scarcely affect on hardness. To verify the variation of tensile strength and shrinkage, morphology of TPE molding was scanned by the SEM. The morphology showed that as the melt temperature increased, the rubber particles on the TPE became smaller and widely were dispersed. This behavior of rubber particles influenced on the increase of tensile strength.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 춘계학술대회 논문집
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• pp.67-69
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• 1988

In this study, after changing the curing condition of hardner(DDM) and filler($SiO_2$) contents dielectric and dynamic mechanical properties were studied according to the variation of temperature. As the result we obtained a correlative $\alpha$-peak at 125-150[$^{\circ}C$] from dielectric and mechanical properties. With increasing curing condition and filler contents both dielectric and internal friction loss were, decreased, peak temperature shifted to high temperature, but there was no variation on peak temperature with filler contents. As the above result we knew the correspondence between dielectric and mechanical characteristics.

• 한국수산과학회지
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• 제36권6호
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• pp.632-640
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• 2003

Geographic variation in shell morphology of Thais clavigera $(K\"{u}ster)$ (Gastropoda: Muricidae) was investigated using samples collected from 24 sites along the Korean coast. Multivariate statistical analysis was applied to 9 morphometric and 4 categorical variables. The shells of T. clavigera were classified into two distinct morph types (Type-W and -E). Temperature and salinity of the sampling sites were significantly correlated with the incidence of morph types. Relative abundance of Type-W (thin, yellowish brown shell with triangular nodules) was positively correlated with temperature and negatively correlated with salinity. In contrast, relative abundance of Type-E (thick, dark purple shell with round nodules) was negatively correlated with temperature and positively correlated with salinity. Possible correlation between environmental factors (temperature and salinity) and morphological variations in the shells were discussed.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.2036-2041
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• 2014

In this paper, a thermal model is developed for the bus bar system to predict the temperature variation during the transient time period and to calculate both the steady-state and transient electrical current carrying capacity (ampacity) of bus bar. The bus bar system installed in the power house of Kumaraguru College of Technology, Coimbatore has been considered. Temperature variation predicted in the modelling is validated by observing the current and steady state temperatures in different feeders of the bus bar. Magnetic field of the extreme phases R and B induces more current in the middle phase Y. Hence, the steady state temperature in the phase Y is greater than other two phases. The transient capabilities of the bus bar are illustrated by calculating the variations in the bus bar temperature when it is subjected to a step change in current during the peak hours due to increase in hostel utilities and facilities (5.30 pm to 10.30 pm). The physical and geometrical properties of the bus bar and temperature variation in the bus bar are used to estimate the thermal time constants for common bus bar cross-sections. An analytical expression for the time constant of the bus bar is derived.

• 상하수도학회지
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• 제11권2호
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• pp.76-93
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• 1997

Activated carbon is widely used for the treatment of water, wastewater and other liquid wastes. Biological activated carbon (BAC) process is water and wastewater treatment process developed in the 1970's. In addition to activated carbon adsorption, biodegradation organic pollutants occurs in the BAC bed where a large amount of aerobic biomass grows. This results in a long operation time of the carbon before having to be regenerated and thus a low treatment cost. Although the BAC process has been widely used, its mechanisms have not been well understood, especially the relationship between biodegradation and carbon adsorption, whether these two reactions can promote each other or whether they just simultaneously exist in the BAC bed. Also, the phenomenon of bioregeneration has been confused that previously occupied adsorption sites appear to be made available through the actions of microorganisms. And that, because biological process is influenced by low temperature, the mechanism of the BAC process is also effected by temperature variation in our country of winter temperature near the freezing point. Therefore, the objective of this study examines closely the mechanism of the BAC process by temperature variation using phenol as substrate. From this study, biological activated carbon is good substrate removal better than non adsorbing materials (charcoal, sand) as temperature variation, especially low temperature(near $5^{\circ}C$).