• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.130-135
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• 2009

These days, the super high-rise buildings construction plans are increased in Korea. But the stack effect in the super high-rise building interrupts the smoke control system's operation because of pressure difference, so it is more dangerous than the general building when firing. Therefore it needs to study about the pressure difference in the super high-rise buildings. We research the smoke control influence factor in the super high-rise building. Reflecting the influence factor, the simulation is practiced the case by case.

• Journal of Mechanical Science and Technology
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• v.19 no.12
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• pp.2303-2311
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• 2005

Super low temperature has many applications nowadays, from the chemical processing, automotives manufacturing, plastic recycling, etc. Considering of its wide application in the present and the future, study of the super-low temperature refrigeration system should be actively carried out. Super low state temperature can be achieved by using multi-stage refrigeration system. This paper present the development and testing of cascade refrigerator system for achieving super-low temperature. On this experiment, two different types of HCFCs refrigerants are utilized, R-22 and R-23 were applied for the high stage and the low-pressure stage respectively. The lowest temperature in the low-pressure evaporator that can be achieved by this cascade refrigeration system is down to $-85^{\circ}C$. This experiment is aimed to study the effect of inlet pressure of the low-pressure stage evaporator and low-pressure stage compressors inlet pressure characteristics to the overall temperature characteristics of cascade refrigeration system.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.4
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• pp.382-389
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• 2021

By applying super-high pressure (150-250 MPa) to a sealed pressure vessel, it is possible to make oyster shucking machine that automatically opens two-sheet shellfish or oysters. Possibility of developing a shucking machine was confirmed by identifying the working pressure for meat of oysters produced in the southern coast and conducting sensory evaluation of meat oysters. As a result of confirming the shucked oysters under super-high pressure of 150 MPa in the pressure vessel, the number of type A with separated shells and well-separated meat was 22 and type B with both shells and internal meat and shells not separated. For the oysters that were treated at 175 MPa, there were 58 type As with shell separated and meat well separated and 42 type Bs without oyster shells and insides. When looking at the oysters shucked at 200 MPa in the pressure vessel, the number of type A was 86 and type B was 14 accounting for 86% of oysters with good marketability. As a result of shucking oysters by applying 250 MPa, 96% type A oysters and 4% type B oysters were obtained from the total specimen. The total specimen oyster weight used in the conducted experiment was 6 kg, the average oyster shell weight was 3.99 kg and the average oyster meat weight was 1.25 kg. Therefore, the fatness of oyster meat, which measures the added value of oysters, is 20.8%. Sensory evaluation was conducted on thinned oysters by hand and type A oysters shelled by machine with an operating pressure of 200 MPa. The hand-worked oyster sample scored 4.7 points only in salty taste, and scored 5.0 or higher in color, shape, smell, fishy taste, texture and preference.

• Journal of the Korean Ceramic Society
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• v.49 no.2
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• pp.167-172
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• 2012

Fine diamond powders are synthesized with a 420 ${\phi}$ cubic press and stack-cell composed of Kovar ($Fe_{54}Ni_{29}Co_{17}$) (or Kovar+7 ${\mu}m$-thick Zn electroplated) alloy and graphite disks. The high pressure high temperature (HPHT) process condition was executed at $1500^{\circ}C$ for 280 seconds by varying the nominal pressure of 5.7~10.6 GPa. The density of formation, size, shape, and phase of diamonds are determined by optical microscopy, field emission scanning electron microscopy, thermal gravimetric analysis-differential thermal ammnlysis (TGA-DTA), X-ray diffraction (XRD), and micro-Raman spectroscopy. Through the microscopy analyses, we found that 1.5 ${\mu}m$ super-fine tetrahedral diamonds were synthesized for Zn coated Kovar cell with whole range of pressure while ~3 ${\mu}m$ super-fine diamond for conventional Kovar cell with < 10.6 GPa. Based on $750^{\circ}C$ exothermic reaction of diamonds in TGA-DTA, and characteristic peaks of the diamonds in XRD and micro-Raman analysis, we could confirm that the diamonds were successfully formed with the whole pressure range in this research. Finally, we propose a new process for super-fine diamonds by lowering the pressure condition and employing Zn electroplated Kovar disks.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.217-222
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• 2004

High ambient interstellar pressure is suggested as a possible factor to explain the ubiquitous ob-served growth-rate discrepancy for supernova-driven super bubbles and stellar wind bubbles. Pressures of P / k ${\~} 10^5\;cm^{-3}$ K are plausible for regions with high star formation rates, and these values are intermediate between the estimated Galactic mid-plane pressure and those observed in starburst galaxies. High-pressure components also are commonly seen in Galactic ISM localizations. We demonstrate the sensitivity of shell growth to the ambient pressure, and suggest that super bubbles ultimately might serve as ISM barometers.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.10
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• pp.1427-1434
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• 2003

Turbo- or Super-charging has been used to boost engine power for Gasoline- and Diesel Engine since beginning of 20th century. So far turbo-charger has enjoyed a high reputation in the charging field for its technical advantages such as no demand of operation power from engine and an excellent charging effect in a static operation at mid- and high engine speed. A mechanically driven super-charger, however, is now popular due to the high engine power at quick change of the driving mode - high engine torque even at low engine speed. Since super-charger needs operation power from engine, it is difficult to improve its relatively higher fuel consumption than that of turbo-charger. This negative point is still an obstacle to the wide use of supercharger. Super-charger using screw-type compressor will fulfill the purpose to reduce fuel consumption by minimizing operation power owing to no charge at idling or part load driving condition. This study aims to develop power control concept to achieve the minimization of operation power. A screw type super-charger was modified in design partially and installed with an internal bypass valve and a bypass tube to control charging pressure at part load. The various control concepts show a possibility to reduce operation power of super-charger.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.12 no.1
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• pp.141-148
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• 2016

This paper presents an overview of worldwide electric power development and National $700^{\circ}C$ Hyper Supercritical coal-fired power generation(HSC) focus on materials and manufacturing process. To Increase the efficiency of electric power generation, It is necessary to increase steam temperature and pressure. In that case, New material and manufacturing process shall be developed for boiler and turbine component in high temperature and pressure operating condition. Therefore, Much Efforts in worldwide are progressing to develop materials and manufacturing technology and to build and operate an HSC.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.2
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• pp.72-79
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• 2022

Deep-learning-based Super-Resolution (SR) methods were evaluated to reconstruct pressure fields with a high resolution from low-resolution images taken from a coarse grid simulation. In addition to a canonical SRCNN(super-resolution convolutional neural network) model, two modified models from SRCNN, adding an activation function (ReLU or Sigmoid function) to the output layer, were considered in the present study. High resolution images obtained by three models were more vivid and reliable qualitatively, compared with a conventional super-resolution method of bicubic interpolation. A quantitative comparison of statistical similarity showed that SRCNN model with Sigmoid function achieved best performance with less dependency on original resolution of input images.

• Wind and Structures
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• v.24 no.2
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• pp.145-169
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• 2017

The auxiliary structures of a high-rise building, such as balconies, ribs, and grids, are usually much smaller than the whole building; therefore, it is difficult to simulate them on a scaled model during wind tunnel tests, and they are often ignored. However, they may have notable effects on the local or overall wind loads of the building. In the present study, a series of wind pressure wind tunnel tests and high-frequency force balance (HFFB) wind tunnel tests were conducted on rigid models of an actual super high-rise building with vertical ribs protruding from its facades. The effects of the depth and spacing of vertical ribs on the mean values, fluctuating values and the most unfavorable values of the local wind pressure coefficients were investigated by analyzing the distribution of wind pressure coefficients on the facades and the variations of the wind pressure coefficients at the cross section at 2/3 of the building height versus wind direction angle. In addition, the effects of the depth and spacing of vertical ribs on the mean values, fluctuating values and power spectra of the overall aerodynamic force coefficients were studied by analyzing the aerodynamic base moment coefficients. The results show that vertical ribs significantly decrease the most unfavorable suction coefficients in the corner recession regions and edge regions of facades and increase the mean and fluctuating along-wind overall aerodynamic forces.

• The Journal of the Petrological Society of Korea
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• v.5 no.2
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• pp.129-134
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• 1996

Possibile phase transitions of graphite have been examined experimentally using piston cylinder and DAC with synchrotron radiation. The graphite-forming processes in high pressure and low temperature conditions and the phase change under super high pressure were studied in the conditions of 0.7 Gpa and 270-$360^{\circ}C$ in piston cylinder and under 39.6 Gpa in DAC. In the piston cylinder experiment using LiCO3as a catalyzer, we could synthesize disordered graphites whose TGD values change progressively form 9 to 53. It was known that the temperature of graphitization in 0.7 Gpa is between 270-$300^{\circ}C$. Numerous unknown XRD peaks were observed in the super high-pressure experiment. However, it is difficult to pick up a new peak of a hexagonal diamond phase. Application of the different high pressure apparatus as well as a peculiar X-ray source and various graphite specimen would be useful for super high-pressure experiment, and more detailed works are needed to characterize the unknown phase(s) observed in this study.