• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.1
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• pp.124-131
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• 2000

In this study, pool boiling performance of Turbo/B-type metal-formed tubes was investigated. Tubes with three different cavity gap width(0.04 mm, 0.07 mm, 0.1 mm) were manufactured and tested using R-11, R-123 and R-134a. Tests were conducted at two different saturation temperatures $4.4^{\circ}C$ and $26.7^{\circ}C.$ Heat flux was varied from 10 kW/m2 to 50 kW/m2. It was found that optimum gap width varied for different refrigerants. For low-pressure refrigerants such as R-11 or R-123, optimum gap width was 0.07 mm. For high-pressure refrigerant R-134a, however, the optimum value was 0.1 mm. Compared with the heat transfer performance of the smooth tube, the metal-formed tubes enhanced the heat transfer coefficients significantly - 6.5 times for R-11, 6.0 times for R-123 and 5.0 times for R-134a (at $4.4^{\circ}C$ saturation temperature and 40 kW/m2 heat flux), which are comparable with the performance of foreign products. The heat transfer coefficients of R-134a were larger than those of R-11 or R-123, and they increased as the saturation temperature increased.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.2
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• pp.106-112
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• 2008

In this paper, the experimental results on evaporation heat transfer characteristics were reported for a micro-fin tube using $CO_2$. An experimental refrigerant loop had been established to measure the evaporation heat transfer coefficient and pressure drop of $CO_2$. Experiments were conducted for mass fluxes, heat fluxes, saturation temperatures and PAG oil concentrations. With increasing the heat flux and the saturation temperature, the evaporation heat transfer coefficient increased. At the higher mass flux, however, the exit vapor quality of the micro-fin tube was to be lower. The peak of the heat transfer coefficient was shifted toward low quality region. The evaporation pressure drop increased as the mass flux increased and the saturation temperature decreased. As PAG oil concentration increased, the evaporation heat transfer coefficient decreased and the dryout was delayed by oil addition.

• Transactions of the Korean Society of Mechanical Engineers
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• v.5 no.2
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• pp.151-157
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• 1981

The concept of available evergy has been adopted in terms of effectiveness for and evaporator of vapor power cycle. This kind of practice is emphasezed in a case of heat and power cogeneration in order to find optimum condition for the energy utilzation of the exhaust gas. It has beed shown that the optimum condition can be given in terms of the saturation pressure or the saturation temperature of the working fluid. Similar method has been applide to show that the effectiveness is increased asymptotically with the number of evaporator stanges.

• Korean Journal of Acupuncture
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• v.26 no.4
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• pp.23-38
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• 2009

Objectives : The purpose of this study was to identify the effect of the tonification & sedation manipulation for LI4 and KI7 on lacking of sweating in cold environment. Methods: The participants were divided into 3 groups as intact group without acupuncture, acupuncture group inserting and twisting with LI4 tonificaton and KI7 sedation method(LI4-tonify KI7-purge) and acupuncture group inserting and twisting with LI4 sedation and KI7 tonificaton method(LI4-purge KI7-tonify). We obtained baseline data at cold condition with the temperature $14{\pm}1^{\circ}C$. After making the participant staying in cold condition for 10 minute, we measured sweating rate in skin surface, body temperature, oxygen saturation, pulse rate, systolic blood pressure, diastolic blood pressure, deoxy-Hb and oxy-Hb in subcutaneous. Results : After acupuncture in cold environment, the sweating rate in skin surface significantly decreased in KI7-purge LI4-tonify group comparing the intact groups. The body temperature significantly increased in LI4-tonify KI7-purge and LI4-purge KI7-tonify groups comparing the intact group. The oxygen saturation significantly increased in LI4-tonify KI7-purge group comparing the intact group. Conclusions : These findings indicated that LI4 tonificaton and KI7 sedation method(LI4-tonify KI7-purge) could be effective for production of sweating in cold condition.

• The Journal of the Petrological Society of Korea
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• v.14 no.2 s.40
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• pp.83-92
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• 2005

It has recently been proposed that granites can be divided into hot and cold ones by absence and presence of inherited zircon, respectively, which is closely related to zircon saturation temperature. The Phanerozoic granites in South Korea are divided into high- and low-Zr groups in a $SiO_2-Zr$ diagram, which appears to be related to their intrusive age. Most Triassic-Jurassic granites belong to low-Zr group, whereas most Cretaceous-Early Tertiary granites belong to the high-Zr group with the exception of geographically distinct Masan and Jinhae granites that belong low-Zr group. Calculated zircon saturation temperatures using major elements and Zr contents indicate that the Cretaceous-Early Tertiary granites $(608-834^{\circ}C,\;average\; 782\pm31^{\circ}C)$ except for the Masan and Jinhae granites $(average\;759\pm16^{\circ}C)$ show higher temperature than the Triassic-Jurassic granites $(642-824^{\circ}C,\;average\;756\pm31^{\circ}C)$. U-Pb zircon isotope data of the Triassic-Jurassic granites reported so far define discordia in a concordia diagram, which indicates presence of inherited zircon and agrees with their low zircon saturation temperatures. So the Triassic-Jurassic granites appear to belong to cold granite. On the other hand, presence or absence of inherited zircon has not been known for the Cretaceous-Early Tertiary granites with relatively high zircon saturation temperature, so that their classification into hot or cold granite awaits further study. Nevertheless, the Creatceous-Early Tertiary granites may have formed at higher temperature than the Triassic-Jurassic granites, since zircon saturation temperature reflects formation temperature of magma to a certain degree.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.1
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• pp.57-64
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• 2004

Effects of light and temperature on the nitrate uptake and germling growth of Enteromorpha compressa (L.) Greville (Chlorophyta) were studied based on samples from Cheongsapo near Busan, Korea. In addition, their effects on fatty acids composition in thallus were examined. Nitrate uptake showed saturation kinetics. $V_{max}$ (maximal uptake rate) and its $K_s$ (half-saturation constant) at $20^{\circ}C,\;80\;{\mu}mol\;m^{-2}s^{-1},$ white light were $1.571\;{\mu}mol{\cdot}g\;fr\;wt^{-1}{\cdot}h^{-1}$ and 3.56 ${\mu}M$, respectively. In nitrate uptake with irradiance, wavelength and temperature, its rate represented respectively the highest value as $1.405\pm0.020,\;0.623\pm0.040,\;1.422\pm0.022\;{\mu}mol{\cdot}g\;fr\;wt^{-1}{\cdot}h^{-1}\;at\;100\;{\mu}mol\;m^{-2}s^{-1},$ red light, $20^{\circ}C$ and exhibited significant difference among the examined conditions (p<0.001). Germling growth of E. compressa also showed saturation kinetics, and $V_{max}$ and its $K_s$ value at $20^{\circ}C,\;100\;{\mu}mol\;m^{-2}s^{-1},$ 12:12 h were $56.18\%\;day^{-1}$ and 0.33 ${\mu}M$, respectively. SGR (specific growth rate) recorded a maximal value as 49.33-54.80, 39.07-50.72, $47.20-54.53\%\;dat^{-1}$ at $120\;{\mu}mol\;m^{-2}s^{-1},$ blue light and $18^{\circ}C$ respectively, and showed significant difference (p<0.001). Red light made the effective nitrate uptake, but germling growth was largely limited by the light. In fatty acids analysis, PUFAs (polyunsaturated fatty acids) were high at blue light, $18^{\circ}C,\;100\;{\mu}M\;NO_3^-.$ However, irradiance did not affect the production of PUFAs. In conclusion, nitrate uptake and germling growth of E. compressa showed saturation kinetics to external nitrate concentration, and were significantly affected by irradiance, wave length and temperature. Fatty acid composition was also influenced by the factors except for irradiance. Their maximal values, together with the highest production of PUFAs, were found at blue light band, $20^{\circ}C,\;100\;{\mu}mol\;m^{-2}s^{-1},\;and\;100\;{\mu}M\;NO_3^-.$

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.8
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• pp.1999-2011
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• 1995

Computer simulation was conducted to study performance characteristics of air-cooled condenser of a double effect absorption heat pump with variations of saturation pressures and mass flow rates of the refrigerant ; volume flow rates, relative humidities and temperatures of the air The vertically installed condenser had the staggered tube array with continuous plate fins of wavy type. When the saturation pressure of the condenser was decreased from 760 torr to 20 torr, heat transfer rates and condensing rates of refrigerant were decreased. If excess refrigerant flows in the condenser, the pressure and saturation temperature of the condenser were increased which makes the refrigerating capacity of an absorption heat pump reduced.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.34.2-34.2
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• 2009

The relativistic Weibel instability has drawn attention as a main mechanism of the magnetic generation in the core of galaxies or in the formation of universe. The Weibel instability is not yet fully understood in the relativistic region. We investigated nonlinear saturation and decay of the relativistic Weibel instability. It is found that the early phase of the instability is in excellent agreement with the linear theory. But, an analysis based on an alternative magnetic trapping saturation theory reveals that a substantial discrepancy between the theory and simulation is revealed in the relativistic regime in contrast to an excellent agreement in the non-relativistic regime. The analysis of the Weibel instability beyond the quasilinear saturation stage shows an inverse cascade process via a nonlinear decay instability involving electrostatic fluctuation.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.92-93
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• 2002

The substituted lithium ferrites combine useful ferromagnetic properties with high Curie temperature ranging from 55$0^{\circ}C$ to 85$0^{\circ}C$, [1] high saturation magnetization, [2] and low microwave dielectric loss.[3] Saturation magnetization of (Z $n_{1-x}$ F $e_{x}$)A[L $i_{0.5x}$F $e_{ 2-0.5x}$]$_{B}$ $O_4$ increased with zinc concentration, followed by a decrease at x = 0.7.[4] This is attributed to a dilution of the A-site with zinc which initially causes an increase in saturation magnetization due to the dominance of the B-site. (omitted)d))d)d))

• Journal of ILASS-Korea
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• v.10 no.1
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• pp.1-9
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• 2005

When the water jets heated up to the saturation temperature at a high line pressure are sprayed into a reduced (atmospheric) pressure through an air-assisted nozzle, the jets experience sudden exposure into a reduced pressure, get superheated and produce steam bubbles while atomization processes of jets are taking place. This process is called flash atomization. In this study the flash atomization of superheated water jets assisted by air has been studied. Sprays with flash atomization have been photographed at various water and air flow rates and water superheats. It has been found that the spray angle with flash atomization increases with water superheat and water flow rate but decreases with air flow rate. The degree of change of spray angle has been analyzed and correlated as a function of superheat, air and water flow rates.