• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.1
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• pp.115-127
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• 2018

This study aims to propose management strategies of ventilation paths for improving urban thermal environments. For this purpose, Gimhae-si in Gyeongsangnamdo was selected as a study area. We analyzed hot spots and cool spots in Gimhae by using Landsat 8 satellite image data and spatial statistical analysis, and finally derived the vulnerable areas to thermal environment. In addition, the characteristics of ventilation paths including wind direction and wind speed were analyzed by using data of the wind resource map provided by Korea Meteorological Administration. As a result, it was found that a lot of hot spots were similar to those with weak wind such as Jinyoung-eup, Jillye-myeon, Juchon-myeon and the downtown area. Based on the analysis, management strategies of ventilation paths in Gimhye were presented as follows. Jinyoung-eup and Jillye-myeon with hot spot areas and week wind areas have a strong possibility that hot spot areas will be extended and strengthened, because industrial areas are being built. Hence, climate-friendly urban and architectural plans considering ventilation paths is required in these areas. In Juchon-myeon, where industrial complexes and agricultural complexes are located, climate-friendly plans are also required because high-rise apartment complexes and an urban development zone are planned, which may induce worse thermal environment in the future. It is expected that a planning of securing and enlarging ventilation paths will be established for climate-friendly urban management. and further the results will be utilized in urban renewal and environmental planning as well as urban basic plans. In addition, we expect that the results can be applied as basic data for climate change adaptation plan and the evaluation system for climate-friendly urban development of Gimhye.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.1
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• pp.49-55
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• 2009

Our domestic economy has been developed very rapidly after 1960's. Also, it is dramatically increasing traffic on road and surround environmental issues. Especially, rapid economic growth has been induced large construction of pavement, and bigger and higher traffic for transportation. These are making air pollution, traffic noise and vibration. The social requirement against the revealed road environment and traffic sound reduction is being demanded. Traffic noise of city zone is showed over the environmental specification more than 57%. In order to overcome these situations, the social attention is being increased. The quiet pavement is the same format of permeable pavement, but is not same for functional performance. In this research, it has been carried out to evaluate the fundamental-mechanical properties of hot mix asphalt for quiet pavement. Especially, couple of laboratory tests are conducted like marshall stability, resilient modulus, indirect tensile test, and compaction energy analysis with gyratory compaction curve. Also, two-layer pavement system has been adopted for developing of quiet pavement. The basic performance of hot mix asphalt of quiet pavement show a satisfaction of specification of hot mix asphalt.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.1-10
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• 2010

Recently heterogeneous storage system such as hybrid hard disk drive (H-HDD) combining flash memory and magnetic disk is launched, according as the read performance of NAND flash memory is enhanced as similar to that of hard disk drive (HDD) and the power consumption of NAND flash memory is reduced less than that of HDD. However, the read and write operations of NAND flash memory are slower than those of rotational disk. Besides, serious overheads are incurred on CPU and main memory in the case that intensive write requests to flash memory are repeatedly occurred. In this paper, we propose the Least Frequently Used-Hot scheme that replaces the data blocks whose reference frequency of read operation is low and update frequency of write operation is high, and the data flushing scheme that rearranges the data blocks into the multi-zone of the rotation disk. Experimental results show that the execution time of the proposed method is 38% faster than those of conventional LRU and LFU block replacement schemes in I/O performance aspect and the proposed method increases the life span of Non-Volatile Cache 40% higher than those of conventional LRU, LFU, FIFO block replacement schemes.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.58.1-58.1
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• 2010

In solar cell module manufacturing, single solar cells has to be joined electrically to strings. Copper stripes coated with tin-silver-copper alloy are joined on screen printed silver of solar cells which is called busbar. The bus bar collects the electrons generated in solar cell and it is connected to the next cell in the conventional module manufacturing by a metal stringer using conventional hot air or infrared lamp soldering systems. For thin solar cells, both soldering methods have disadvantages, which heats up the whole cell to high temperatures. Because of the different thermal expansion coefficient, mechanical stresses are induced in the solar cell. Recently, the trend of solar cell is toward thinner thickness below 180um and thus the risk of breakage of solar cells is increasing. This has led to the demand for new joining processes with high productivity and reduced error rates. In our project, we have developed a new method to solder solar cells with a laser heating source. The soldering process using diode laser with wavelength of 980nm was examined. The diode laser used has a maximum power of 60W and a scanner system is used to solder dimension of 6" solar cell and the beam travel speed is optimized. For clamping copper stripe to solar cell, zirconia(ZrO)coated iron pin-spring system is used to clamp both joining parts during a scanner system is traveled. The hot plate temperature that solar cell is positioned during lasersoldering process is optimized. Also, conventional solder joints after $180^{\circ}C$ peel tests are compared to the laser soldering methods. Microstructures in welded zone shows that the diffusion zone between solar cell and metal stripes is better formed than inIR soldering method. It is analyzed that the laser solder joints show no damages to the silicon wafer and no cracks beneath the contact. Peel strength between 4N and 5N are measured, with much shorter joining time than IR solder joints and it is shown that the use of laser soldering reduced the degree of bending of solar cell much less than IR soldering.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.4
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• pp.152-158
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• 2018

PVT (Physical Vapor Transport) method has advantages in producing high quality, large scale wafers where many researches are being carried out to commercialize nitride semiconductors. However, complex process variables cause various defects when it had non-equilibrium growth conditions. Annealing process after crystal growth has been widely used to enhance the crystallinity. It is important to set appropriate temperature, pressure, and annealing time to improve crystallinity effectively. In this study, the effect of the annealing conditions on the crystalline structure variation of the AlN single crystal grown by PVT method was investigated with synchrotron whitebeam X-ray topography, electron backscattered diffraction (EBSD), and Rietveld refinement. X-ray topography analysis showed secondary phases, sub-grains, impurities including carbon inclusion in the single crystal before annealing. EBSD analyses identified that sub-grains with slightly tilted basal plane appeared and the overall number of grains increased after the annealing process. Rietveld refinement showed that the stress caused by the temperature gradient during the annealing process between top and bottom in the hot zone not only causes distortion of grains but also changes the lattice constant.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.5
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• pp.179-184
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• 2018

To lessen oxygen concentrations in a wafer through modifying the length of graphite heaters, we investigated the influence of relative distance from heater to quartz crucible on temperature profile of hot-zone in Czochralski silicon-crystal growth by simulation. In particular, ATC temperature and power profiles as a function of different ingot body positions were investigated for five different heater designs; (a) typical side heater (SH), (b) short side heater-up (SSH-up), (c) short side heater-low (SSH-low), (d) bottom heater without side heater (Only-BH), and (e) side heater with bottom heater (SH + BH). It was confirmed that lower short side heater exhibited the highest ATC temperature, which was attributed to the longest distance from triple point to heater center. In addition, for the viewpoint of energy efficiency, it was observed that the typical side heater showed the lowest power because it heated more area of quartz crucible than that of others. This result provides the possibility to predict the feed-forward delta temperature profile as a function of various heater designs.

• Journal of the Mineralogical Society of Korea
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• v.15 no.3
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• pp.205-220
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• 2002

The gold-silver deposits in the Casado district were formed in the sheeted and stockwork quartz veins which fill the fault fractures in volcanic rocks. K-Ar dating of alteration sericite (about 70 Ma) indicates a Late Cretaceous age for ore mineralization. These veins are composed of quartz, adularia, carbonate, and minor of pyrite, sphalerite, chalcopyrite, galena, Ag-sulfosalts (argentite, pearceite, Ag-As-Sb-S system), and electrum. These veins are characterized by chalcedonic, comb, crustiform and feathery textures. Based on the hydrothermally altered mineral assemblages, regional alteration zoning associated with mineralization in the Gasado district is defined as four zones; advanced argillic (kaolin mineral-alunite-quartz), argillic (kaolin mineral-quartz), phyllic (quartz-sericite-pyrite) and propylitic (chlorite-carbonate-quartz-feldspar-pyroxene) zone. Phyllic and propylitic zones is distributed over the study area. However, advanced argillic zone is restricted to the shallow surface of the Lighthouse vein. Compositions of electrum ranges from 14.6 to 53.7 atomic % Au, and the depositional condition for mineralization are estimated in terms of both temperature and sulfur fugacity: T=245。$~285^{\circ}C$, logf $s_2$=$10^{-10}$ ~ $10^{-12}$ Fluid inclusion and stable isotope data show that the auriferous fluids were mixed with cool and dilute (158。~253$^{\circ}C$ and 0.9~3.4 equiv. wt. % NaCl) meteoric water ($\delta^{18}$ $O_{water}$=-10.1~8.0$\textperthousand$, $\delta$D=-68~64$\textperthousand$). These results harmonize with the hot-spring type of the low-sulfidation epithermal deposit model, and strongly suggest that Au-Ag mineralization in the Gasado district was formed in low-sulfidation alteration type environment at near paleo-surface.

• Nuclear Engineering and Technology
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• v.20 no.2
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• pp.105-111
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• 1988

The chemical effects resulting from the capture of the thermal neutron by manganese in various crystalline permanganates, that is, potassium permanganate ammonium permangante and barium permanganate, have been investigated. The effect of pH of solvent on the distribution of radioactive manganese chemical species, that is, cationic $^{56}$ Mn, $^{56}$ MnO$_2$ and $^{56}$ MnO$_4$$^{[-10]}$ produced in the permanganates by $^{55}$ Mn(n, ｒ) $^{56}$ Mn reaction was studied by using various adsorbents and ion-exchanger, that is, zeolite A-3, kaolinite, alumina, manganese dioxide and Dowex-50 The distribution of radioactive MnO$_4$$^{[-10]}$ in kaolinite and alumina has higher than that in other adsorbents and ion-exchanger at a representative pH value of 4, 7 and 9, respectively. The yield of radioactive MnO$_4$$^{[-10]}$ is higher at pH 4 End pH 9 than at pH 7. The thermal annealing behavior of recoil manganese atoms produced in the permanganates by $^{55}$ Mn(n, ｒ) $^{56}$ Mn reaction was also studied. The retention of MnO$_4$$^{[-10]}$ in the thermal annealing is increased as annealing temperature increases when it was treated at 10$0^{\circ}C$ and 13$0^{\circ}C$. The recoil effect of permanganates was explained by the hot zone model.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.6
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• pp.777-783
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• 2004

Samples of 13 species of forest tree leaves fed to livestock in the semi-hilly arid zone of Punjab State in India were collected at 30 d interval for 12 months, in order to assess their nutritional worth for livestock. The ground samples were pooled for 4 different seasons viz. dry hot, hot humid, fall and winter. The chemical composition irrespective of the season revealed that CP content varied between 8.9 (Carrisa) to 22.0% (Leucaena). Globulin was the major protein fraction in most of the leaves. The lowest concentration of cell wall constituents was observed in Morus alba and Grewea. The leaves in general became fiberous and lignified during winter and fall as compared to summer season. The leaves of Grewea, Morus alba, Leucaena, Carrisa and Acacia were rich in Ca, P and most of the trace elements. The total phenolics ranged between 1.88% (Azardirachta) to 15.82% (Acacia). The leaves of Acacia had the highest concentration of hydrolysable tannins (14.6%) whereas that of Carrisa had that of condensed tannins (5.9%). The condensed tannins (more than 3%) were negatively correlated to the digestibility of dry matter (DM), neutral detergent fiber (NDF) and crude protein (CP). The digestion kinetic parameters for DM, NDF and CP revealed that leaves of Morus alba, Zizyphus and Ehretia had highest insoluble but potentially degradable fraction. The minimum rumen fill values also revealed that leaves of Grewea, Azardirachta, Morus, Ehretia and Leucaena had great potential for voluntary DM intake. The leaves of Ougeinia, Malha, Dodenia and Carrisa had significantly higher rumen fill value indicating poor potential for voluntary DM intake. Season did not have any significant impact on digestion kinetic parameters except that most of the leaves had low potentially degradable fraction, which was degraded at slow rate during winter. It was concluded that the leaves of Morus, Ehretia, Grewea and Leucaena had great potential as livestock feed, while feeding of Ougeinia, Malha and Dodonea leaves should be avoided.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.510-519
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• 2001

The tensile and fracture toughness tests have been conducted to investigate the degradations of mechanical properties induced mainly by neutron irradiations in Zr-2.5Nb CANDU pressure tube materials operated in Wolsung Unit-1. the tests were performed at room, 150, 200, 250, 300 $\^{C}$ for the irradiated and unirradiated specimens in hot cell. The specimens were directly machined from the tube retaining original curvature using specially designed electric discharge machine(EDM). From the tensile tests of the irradiated specimens, it was found that tensile strength was increased and total elongation was decreased compared to those of the unirradiated ones. The active voltages in the fracture toughness tests for the irradiated showed the discontinuous abrupt increases caused by crack jumping in lower temperature. In the crack resistance curves we found the stable crack growth in the unirradiated, whereas the unstable and three crack growth stages in the irradiated specimens due to the accumulated irradiation defects. The various fracture characteristic values in the irradiated are remarkably lower than those of the unirradiated. Through the fractography, we found in the irradiated that smaller dimple and shorter fissures than the unirradiated, and that the fractured surface had three regions that were flat, transition and slant/shear area. These can explain the difference in the crack growth characteristic values of the irradiated and the unirradiated ones.