• Journal of the Korea Society of Computer and Information
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• v.14 no.3
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• pp.41-49
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• 2009

Flash memory has become increasingly requestion for the importance and the demand as a storage due to its low power consumption, cheap prices and large capacity medium. This research is to design a high performance flash memory structure for the substitution of a hard-disk by dynamic prefetching of aggressive spatial locality from the spatial smart buffer system. The proposed buffer system in a NAND flash memory consists of three parts, i.e., a fully associative victim buffer for temporal locality, a fully associative spatial buffer for spatial locality, and a dynamic fetching unit. We proposed new dynamic prefetching algorithm for aggressive spatial locality. That is to use the flash memory instead of the hard disk, the proposed flash system can achieve better performance gain by overcoming many drawbacks of the flash memory by the new structure and the new algorithm. According to the simulation results, compared with the smart buffer system, the average miss ratio is reduced about 26% for Mediabench applications. The average memory access times are improved about 35% for Mediabench applications, over 30% for Spec2000 applications.

• Journal of agriculture & life science
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• v.50 no.5
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• pp.61-68
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• 2016

This study was focused to examine the effects of pre- or post-harvest Ca-chitosan treatment on the shelf-life of 'Daesung' hardy kiwifruit. In the preharvest treatment, Ca-chitosan at 200 mg/L was intensively sprayed to the fruit three times on August 20, 25, and 28 in an order whereas harvested fruits were dipped for 10 sec. at the same concentration of chitosan as the postharvest treatment. Fruits were stored at 17℃ for 9 days and 1℃ for 40 days, respectively. Soluble solid contents, titratable acidity, firmness, respiration rate, and weight loss were examined to configure the qualities of fruits during storage. The changes of fruit quality parameters occurred more rapidly in calcium-chitosan treatment compared to untreated control when fruit were stored at 17℃. Both pre- or post-harvest Ca-chitosan treatment, however, effectively decreases the weight and firmness of fruit stored at 1℃. Fruit respiration rate was also reduced, indicating the increase of shelf-life throughout ripening of the fruit.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.407-411
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• 2023

The urease is covalently immobilized on the surface of the magnetic particles to catalyze the conversion of urea to bicarbonate anion. The conversion was confirmed qualitatively using high-pressure liquid chromatography and UV/Vis spectrometry, and analyzed quantitatively with cyclic voltammetry. The amount of conversion with respect to time was measured and analyzed by the reaction rate equation to calculate a reaction rate constant of 0.0474 min-1. In the 1 to 3 cycles, a conversion percentage of over 90% was found, and it was possible to reuse the urease 8 times up to the percentage of 50%. It was also observed that the stability evaluated for storage for 30 days was maintained. As a result of this study, it can be seen that the urease covalently immobilized on the scaffold can be used for urea removal for the purpose of producing ultrapure water.

• Journal of Korean Port Research
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• v.5 no.2
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• pp.19-37
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• 1991

This work aims to : establish a model of the container physical distribution system of Pusan port comprising 4 sub-systems of a navigational system, on-dock cargo handling/transfer/storage system, off-dock CY system and an in-land transport system : examine the system regarding the cargo handling capability of the port and analyse the cost of the physical distribution system. The overall findings are as follows : Firstly in the navigational system, average tonnage of the ships visiting the Busan container terminal was 33,055 GRT in 1990. The distribution of the arrival intervals of the ships' arriving at BCTOC was exponential distribution of $Y=e^{-x/5.52}$ with 95% confidence, whereas that of the ships service time was Erlangian distribution(K=4) with 95% confidence, Ships' arrival and service pattern at the terminal, therefore, was Poisson Input Erlangian Service, and ships' average waiting times was 28.55 hours In this case 8berths were required for the arriving ships to wait less than one hour. Secondly an annual container through put that can be handled by the 9cranes at the terminal was found to be 683,000 TEU in case ships waiting time is one hour and 806,000 TEU in case ships waiting is 2 hours in-port transfer capability was 913,000 TEU when berth occupancy rate(9) was 0.5. This means that there was heavy congestion in the port when considering the fact that a total amount of 1,300,000 TEU was handled in the terminal in 1990. Thirdly when the cost of port congestion was not considered optimum cargo volume to be handled by a ship at a time was 235.7 VAN. When the ships' waiting time was set at 1 hour, optimum annual cargo handling capacity at the terminal was calculated to be 386,070 VAN(609,990 TEU), whereas when the ships' waiting time was set at 2 hours, it was calculated to be 467,738 VAN(739,027 TEU). Fourthly, when the cost of port congestion was considered optimum cargo volume to be handled by a ship at a time was 314.5 VAN. When the ships' waiting time was set at I hour optimum annual cargo handling capacity at the terminal was calculated to be 388.416(613.697 TEU), whereas when the ships' waiting time was set 2 hours, it was calculated to be 462,381 VAN(730,562 TEU).

• Korean Journal of Poultry Science
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• v.15 no.4
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• pp.261-268
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• 1988

The effect of two particle size ranges (80% of the particles in the ration less than 1.19mm ; and 40% of the particles in the ration less than 1.1mm) and two different levels of protein (18% and 12% ) on the activity of mold inhibitors in commercial ration was determined by measuring mold count, CO$30^{\circ}C$ production and aflatoxin concentration. A commercial fungistat was mixed in the treated diets at the level of 0.1% (W/W). Two types of experimental diets (18% & 12% protein) which contained 12.6 and 12.7% moisture content each were stored under the forced air humidifier at 85% humidity and a controlled-temperature of 29＋1$30^{\circ}C$ for 5 to 40 days. Mold count and CO$30^{\circ}C$ levels in the feed treated with mold inhibitor were significantly higher (P＜0.05 and P＜0.01 respectively) when 40% of the ration's particle size was<1.19mm. The different protein levels in the ration treated with mold inhibitor did not have a significant effect (P＞0.05) on the mold count and $CO_2$ production. Protein level $\times$ particle size range interaction on the $CO_2$ production was significant (P＜0.05). Aflatoxin production in the experimental diet with mold inhibitor was significantly (P＜0.05) affected by the levels of protein and the different particle size ranges. The interaction of protein levels and particle size ranges on the aflatoxin production was significant (P＜0.05) at 40 days of storage.

• Journal of Radiation Industry
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• v.17 no.2
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• pp.161-172
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• 2023

Coal-fired power plants handle large quantities of coal, one of the most prominent NORM, and the coal ash produced after the coal is burned can be tens of times more radioactive than the coal. Workers in these industries may be exposed to internal exposure by inhalation of particles while handling NORM. This study evaluated the size, concentration, particle shape and density, and radioactivity concentrations of airborne suspended particles in the main processes of a coal-fired power plant. Finally, the internal radiation dose to workers from particle inhalation was evaluated. For this purpose, airborne particles were collected by size using a multi-stage particle collector to determine the size, shape, and concentration of particles. Samples of coal and coal ash were collected to measure the density and radioactivity of particles. The dose conversion factor and annual radionuclide inhalation amount were derived based on the characteristics of the particles. Finally, the internal radiation dose due to particle inhalation was evaluated. Overall, the internal radiation dose to workers in the main processes of coalfired power plants A and B ranged from 1.47×10^-5~1.12×10^-3 mSv y^-1. Due to the effect of dust generated during loading operations, the internal radiation dose of fly ash loading processes in both coal-fired power plants A and B was higher than that of other processes. In the case of workers in the coal storage yard at power plants A and B, the characteristic values such as particle size, airborne concentration, and working time were the same, but due to the difference in radioactivity concentration and density depending on the origin of the coal, the internal radiation dose by origin was different, and the highest was found when inhaling coal imported from Australia among the five origins. In addition, the main nuclide contributing the most to the internal radiation dose from the main processes in the coal-fired power plants was thorium due to differences in dose conversion factors. However, considering the external radiation dose of workers in coal-fired power plants presented in overseas research cases, the annual effective dose of workers in the main processes of power plants A and B does not exceed 1mSv y^-1, which is the dose limit for the general public notified by the Nuclear Safety Act. The results of this study can be utilized to identify the internal exposure levels of workers in domestic coal-fired power plants and will contribute to the establishment of a data base for a differential safety management system for NORM-handling industries in the future.

• Journal of Animal Science and Technology
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• v.49 no.5
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• pp.667-676
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• 2007

This study was conducted to determine effects of cellulolytic microbes inoculation to sawdust-based spent mushroom substrate(SMS) during deepstacking on fermentation parameters, total microbial counts and cellulolytic enzyme activity and to on SMS nutrients utilization by sheep. For sheep metabolism trials, six sheep(ram, average 54.8kg) were fed a Control diet(70% concentrates, 15% rice straw and 15% SMS with no microbial treatment on a dry basis) and a Treatment diet(the same diet including SMS with a microbial treatment) for 2 trials. Spent mushroom substrates with or without a microbial(4 strains including 1 strain of Enterobacter ludwigii, 1 strain of Bacillus cereus and 2 strains of Bacillus subtillis) treatment (1% of SMS on wet basis) were deepstacked for 7 days. The internal temperatures in 1.2 M/T of SMS deepstacks reached to 50±5℃ within 7 days of storage. Total microbial counts remarkably decreased (P<0.05) with a deepstacking process and were not affected(P>0.05) by the microbial treatment. For fibrolytic enzyme activity, CMCase and xylanase activities were decreased(P<0.05) by a deepstacking process. After deepstacking, the microbial treatment showed about 2.5-times higher(P<0.05) for CMCase activity and about 4-times higher(P<0.05) for xylanase activity than those of the Control. Activities of ligninolytic enzymes such as laccase and MnP were not affected by the microbial treatment. The sheep fed the microbially treated SMS diet had a tendency of greater total tract digestibilities of ash(P=0.051), NFE (P=0.071), hemicellulose(P=0.087) and NDF(P=0.096) than those fed the untreated SMS diet. Nitrogen balance of sheep was not affected(P>0.05) by feeding of microbially treated SMS. Accordingly, these results indicate that cellulolytic microbes inoculation during deepstacking of SMS may improve the bio- utilization of SMS by sheep.

• Food Science and Preservation
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• v.20 no.6
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• pp.760-765
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• 2013

The image analysis as a tool for evaluation of browning degree on fresh-cut lotus root was studied. The fresh-cut lotus root treated as 4 groups (Cont-without any treatment, DB-blanching at $50^{\circ}C$ for 5 min in distilled water, AB-blanching at $45^{\circ}C$ for 5 min in 1% ascorbic acid, CB-blanching at $45^{\circ}C$ for 5 min in 1% citric acid). The samples treated with each methods were packaged with 0.04 mm polyethylene bag ($25cm{\times}30cm$) and stored at $4^{\circ}C$ for 9 days. On the RGB color space, the AB and CB group showed high R, G, B value. On the HSV and CIE $L^*a^*b^*$ color space, the AB and CB group showed low browning area, $a^*$, $b^*$ value and high $L^*$ value. Polyphenol oxidase activity was low in the AB and CB groups in all storage period. This result means that the AB and CB groups were inhibited the development of tissue browning. The result of sensory evaluation also supported this opinion. And the correlation coefficient between sensory evaluation with all color values was over 0.84. Especially, the $L^*$ value showed the highest correlation coefficient (0.93). In conclusion, the image analysis is suitable for analysis of browning degree on fresh-cut lotus root by analyzing diverse color value.

• Development and Reproduction
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• v.12 no.3
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• pp.221-229
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• 2008

For the clinical application, it is needed to keep characteristics of stem cells after storage for a long time. In the present study, we examined stem cell properties of human cord-derived stem cells (HUC) after cryopreservation. Cells were isolated from human umbilical cord and cultured in vitro. At passage 2 or 3, HUC were suspended at a concentration of $1.0{\times}10^6/m{\ell}$ in cryomedium consisting of DMSO and FBS. After freezing at $-80^{\circ}C$ overnight, HUC were cryopreserved at $-196^{\circ}C$ nitrogen gas. After 6 months, HUC were thawed and cultured in vitro. Assessment for the stem cell properties was made upon the morphology, population doubling time, and expression profiles of genes and various proteins. Cryopreserved HUC showed more than 70% viability and maintained fibroblast-like morphology similar to HUC before cryopreservation. Throughout the culture, they underwent average 42.8 doublings and produced $6.75{\times}{10^{18}}$ cells. RT-PCR analyses showed that cryopreserved HUC expressed Oct-4, nanog, SCF, NCAM, nestin, GATA-4, BMP4, and HLA-1 genes. They did not express Brachyury and HLA-DR genes. Immunocytochemical studies showed that cryopreserved HUC reacted with antibodies against SSEA-3, -4, Thy-1, vimentin, fibronectin, HCAM, ICAM, HLA-1 proteins. They did not react with antibody against HLA-DR protein. Theses genes and proteins expression patterns of cryopresserved HUC were similar to those of HUC before cryopreservation. These results suggest that cryopreserved HUC could retain proliferative potential and they expressed various genes and proteins similar to HUC before cryopreservation. Thus, cryopreservation might be useful for HUC for future research and clinical application.

• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.3
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• pp.157-170
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• 2002

The purpose of this study is to analyze the shear bond strength according to kinds of surface treatment agents and resin cements after acid etching of IPS Empress 2. For this purpose, test groups were classified into silane-treated bonding groups, silica-coated group and Targis link applied group. Then, nine bonding groups in total, each three groups per kind, were prepared by using three kinds of resin cements-Panavia F, Variolink II and Rely-X ARC, and thirty test specimens per group were prepared. To examine any changes in the oral environment, the shear bond strength of each test specimen was measured after dipping test for 24 hours and for five weeks, respectively, in distilled water at $37^{\circ}C$ and performing heat cycle 10,000 times in total, each 2,000 times per week, during a five weeks of dipping, under the condition similar to the oral environment. The bond failure modes were also observed by means of a scanning electron microscope. The results are summarized as follows 1. Statically significant differences between the surface conditioning materials were observed. The shear strength of the silane treatment was the highest of all three types of surface treatments(p<0.001). 2. Shear strengths varied significantly for different types of resin luting agents. But bond strength of Targis link surface treatments were not significantly different(p<0.05). 3. No significant difference of bonding strengths was found between storage time conditions(24 hours and 5 weeks). Only group II, IV, VII, IX were significantly different(p<0.05). 4. After thermocycling, the shear bond strengths of all groups were significantly decreased (p<0.05). Group III, V, VI were no significantly different. 5. On the SEM observation of fractured surfaces, all groups were shown complex failure.