• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.311-315
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• 2000

A numerical investigation is made of time-dependent buoyant convection in a square of a non-Boussinesq fluid. The density-temperature$({\rho}-T)$ relation is modeled by a quadratic function, with the maximum density ${\rho}_M$ at temperature $T_M$. The horizontal walls of the square are insulated, and a pulsating temperature $T_H=T_M+{\Delta}T'\;sin({\omega}{\tau})$ is imposed on the hot vertical sidewall. The temperature at the cold wall $T_c$ is constant. Extensive numerical solutions to the governing Navier-Stokes equations are portrayed. Resonance is identified by monitoring the amplitude of the mid-plane Nusselt number, $A(Nu^*)$. The primary resonance frequency is found by matching ${\omega}$ to the nondimensional basic mode $N_1$ of internal gravity oscillations. Due to the quadratic$({\rho}-T)$ relationship, the effective pulsation frequency for density, $2{\omega}$, is meaningful, which brings forth the secondary resonance frequency, i.e., $2{\omega}=N_1$

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.34-36
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• 2003

In boreal conifers in China's Northeast area, maximum latewood density (MXD) of tree-ring varies in response to growing season temperature. Forest net productivity can be estimated using the Normalized-difference Vegetation Index (NDVI) calculated from satellite sensor data. MXD from the Mohe site in this area was compared with estimates of NPP for 1982-1999 produced by the NDVI model, which was established based on the relationship of leaf area index (LAI) and NDVI. The result shows that the MXD series correlated significantly with the NDVI model estimates series, suggesting that MXD appeared to be an appropriate index for productivity or canopy growth in region where forest productivity is strongly temperature-related.

• 대한치과기공학회지
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• 제32권1호
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• pp.9-16
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• 2010

This study sought to apply different MgO additions to Zirconia (20wt % Frit) and thereby determine its mechanical properties depending upon variation of temperature, as a part of elementary study. First, in terms of sintering density depending on sintering conditions, it was found that sintering density increased as temperature varied from $1100^{\circ}C$ to $1300^{\circ}C$. As the addition of MgO increased, it was found that sintering density tended to decrease at each temperature. For the maximum sintering density obtained from pellet, it was found that 3wt% MgO addition specimens sintered at $1300^{\circ}C$ had its maximum sintering density as high as 97.39%. This study measured mechanical properties of these specimens, and it was found that their bending strength tended to decrease as the content of MgO addition increased. And it was found that their bending strength reached up to 162 MPa when 3wt% MgO was added to them for sintering process at $1300^{\circ}\Delta C$. It was also found that those specimens had Vickers microhardness up to 4.6 GPa when 5wt% MgO was added to them for sintering process at $1300^{\circ}C$.

• Journal of Electrical Engineering and Technology
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• 제8권2호
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• pp.339-344
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• 2013

This research deals with design of the maximum thrust density with considering winding temperature rise of single-sided PMLSM. The temperature rise of winding which caused to machine characteristics such as copper loss, iron loss and efficiency was analyzed by FEM. The maximum allowable current density was calculated within the allowable temperature. The effects of loss and efficiency according to temperature characteristic were confirmed.

• 한국전기전자재료학회논문지
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• 제17권5호
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• pp.492-496
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• 2004

In this study, (0.96 －x)(PSN-PZT)－xBF－0.04 PNW＋0.3wt%MnO$_2$＋0.6wt%CuO ceramics were fabricated with the variations of the amount of BiFeO$_3$substitution and sintering temperature for the development of modified ceramics which can be sintered in the low temperature($\leq$100$0^{\circ}C$ ), and their microstructural, dielectric and piezoelectric characteristics were investigated. As the amount of BiFeO$_3$ substitution was increased, the density, mechanical quality factor(Q$_{m}$) and electromechanical coupling factor(k$_{p}$) showed the maximum value at each of sintering temperature. At sintering temperature of 98$0^{\circ}C$ and BiFeO$_3$substitution of 2 mol%, the density, dielectric constant and electromechanical coupling factor(k$_{p}$) showed the maximum value of 7.84 g/㎤, 1415 and 0.49, respectively. And at sintering temperature of 95$0^{\circ}C$ and BiFeO$_3$substitution of 3mol%, mechanical quality factor showed the maximum value of 1062. 1062.

• 한국자동차공학회논문집
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• 제14권4호
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• pp.68-76
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• 2006

The minimization of maximum DPF wall temperature and the fast Light-off during regeneration are the targets for the high durability of the DPF system and the high efficiency of regeneration. In order to predict transient thermal response of DPF, one-channel numerical modeling has been adopted. The effect of the ratio of length to diameter(L/D), cell density, the amount of soot loading on temporal thermal response and regeneration characteristics has been numerically investigated under two different running conditions: city driving mode and high speed mode. The results indicate that the maximum wall temperature of DPF increase with increasing 'L/D' in 'High speed mode'. For 'City driving mode', the maximum wall temperature decreases with increasing 'L/D' in the range of $'L/D{\geq}0.6'$. The maximum temperature decreases with increasing cell density because heat conduction and heat capacity are increased. It is also found that the effect of amount of soot loading on light-off time is negligible.

• 한국세라믹학회지
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• 제32권7호
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• pp.817-824
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• 1995

TiB2 was simultaneously synthesized and densified with concurrent self-propagating high-temperature synthesis and direct contact-heating by electrcial power input and pressure. Density of TiB2 synthesized by self-propagating high-temperature synthesis and consolidated simultaneously by direct contact-heating and pressure was maximum 80% of the theoretical density (4.52g/㎤). Temperature profile was analyzed by solving heat balance equation with numerical method (FTCS method). The temperature of the sample was sufficiently raised to that temperature sufficient to be densified. It was ascertained that the density of the SHS synthesized TiB2 is exponentially proportinal to the input thermal energy per mass.

• 수산해양교육연구
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• 제26권6호
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• pp.1315-1321
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• 2014

We investigated the optimum salinity and temperature conditions for the mass culture of small rotifer, Proales similis. In the salinity experiment ranging from 1, 5, 10, 15, 20, 25 and 33‰, growth tended to decrease with salinity increase. Most agreeable salinity for rotifer growth was 1‰ in which maximum density and specific growth rate (SGR) were obtained. In the temperature experiments ranging from 15, 20, 25, 30 and $35^{\circ}C$, continuous growth of rotifer populations was found up to $35^{\circ}C$. The highest maximum density (2,060 inds./mL) of rotifer was observed at $25^{\circ}C$ in given temperature regime. Also, the SGR of females showed increasing tendencies with the increase of temperature. These results suggest that the optimum salinity and temperature for mass culture of P. similis may be 1‰ and $25^{\circ}C$, respectively.

• Advances in environmental research
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• 제11권1호
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• pp.17-30
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• 2022

Road transport allows all forms of land conditions to be met at less cost. Because of this function, despite numerous disadvantages, it becomes the most frequently used method of transport, especially in underdeveloped or developing countries. One of the most significant factors used in evaluating the atmosphere's air quality is the amount of CO₂, increasing people's density in indoor spaces. The amount of CO₂ indoors is, therefore, vital to determine. In this study, CO₂ and temperature measurements made on nine different bus journey was made in Turkey. The minimum and maximum values were recorded as 555 ppm and 3000 ppm CO₂, respectively, in the measurements. On all journeys, the average concentration is 1088.72 ppm. The minimum and maximum values were measured as 17.4℃ and 32.7℃ in the temperature measurements, and the average of all trips was calculated to be 25.76℃. In this study conducted before the Covid-19 pandemic, it was determined that the amount of CO₂ increased with the density and insufficient ventilation in the buses. The risk of infection increases in places with high human density and low clean air. For situations such as pandemics, CO₂ measurement is a rapid indicator of determining human density.

• Progress in Superconductivity
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• 제8권1호
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• pp.54-58
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• 2006

We have fabricated double stacked 385 filamentary Bi2212/Ag round wires which have different Ag ratios. The wires have been heat-treated at the maximum temperature($T_{max}$) of $882{\sim}896^{\circ}C$ for 0.5 h. Effect of heat treatment on critical current density and critical temperature on Bi2212/Ag round wires has been studied. Critical current density of the wire heat -treated at $890^{\circ}C$ showed 206,250 $A/cm^2$ at 4.2 K, 0 T and critical temperature of the wire was 83 K. Microstructure of the wires also has been studied via optical microscopy and SEM.