• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.192-193
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• 2005

Magnesium thin films were prepared on cold-rolled steel substrates by RF(Radio Frequency) magnetron sputtering technique.$^{1)}$ The crystal orientation and monitoring of the deposited films were investigated by using XRD(X-ray Diffraction) and EIS(Electrochemical Impedance Spectroscopy), respectively. The corrosion rates of Mg thin films deposited with different argon gas pressure and substrate bias voltage were monitored by AC impedance method under a cyclic wet-dry condition, which was conducted by exposure to alternate conditions of 1h immersion in 3%NaCl solution and 5h drying at 60% RH and 25$^{\circ}C$. The result of corrosion rate of Mg thin films deposited at various Ar gas pressures and substrate bias voltage under wet-dry cyclic exposure in chloride-containing solutions was showed the following conclusions. At the region I during the onset of the wet cycle, corrosion rate showed relatively low value. The increase in the Corrosion rate of region II is due to the increase in the chloride concentration. Corrosion rate of region III during the onset of the cycle zero and salt crystals remain on the metal surface.$^{2)}$

• Journal of Digital Convergence
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• v.13 no.9
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• pp.515-521
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• 2015

In this study, we tried to analyze arterial stiffness of Jeju female divers who diver into cold water without the assistance of oxygen. For this purpose we measured pulse wave velocity and ankle-brachial index of Jeju female divers and same aged females who didn't have any cardiovascular risk for comparing the vascular stiffness. The results were the following : First, the light-femoral pulse wave velocity of Jeju female divers was significantly lower than normal women of the same ages. Second, Jeju female divers's ABI showed higher tendency than normal same aged women. These result showed that Jeju female divers' body had been completed for adaptation to low temperature and high pressure water environment through a long-term immersion activities in old age, as well as due to higher physical activity levels of Jeju female divers peripheral vascular resistance was not reduced.

• Restorative Dentistry and Endodontics
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• v.18 no.1
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• pp.187-196
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• 1993

The purpose of this study was to evaluate the microleakage of retrofilled teeth with various materials [non-zinc Amalgam, IRM, Ketac-silver, CGP(cold-burnished, ultrafil)[and instruments for cavity preparation. Root apex were resected 2mm from apex horizontally and class I cavities were prepared in 2mm denpth, 1.5mm width and were filled with above mentioned materials. Root apex were resected 2mm from apex horizontally and class I cavities were prepared in 2mm depth, 1. 5mm width and were filled with above mentioned materials. 2% methylene blue dye solution was used for 4 days immersion and the linear leakage was measured with calipers and the volumetric leakage was determined with a spectrophotometer. The results were as follows : 1. Amalgam group showed the greatest amount of leakage and Ketac-silver group showed the least value. 2. By linear leakage test, the group retrofilled with Ketac-silver, or CGP showed better seal than the group of Amalgam or IRM. This was shown in both retrograde tip and Conventional method. 3. By volumetric leakage test, the group retrofilled with Ketac-silver showed significantly better seal than the group with IRM in retrograde tip method. 4. By volumetric leakage test, the group retrofilled with Ketac-silver showed significantly better seal than the group with Amalgam in the Conventional method.

• Journal of the Korean Wood Science and Technology
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• v.43 no.2
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• pp.156-167
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• 2015

The aim of this study was to determine the physical and mechanical properties of glued laminated timber (glulam) manufactured from small-diameter logs of three wood species, Acacia mangium (mangium), Maesopsis eminii (manii), and Falcataria moluccana (sengon), with densities of 533, 392, and $271kg/m^3$, respectively. Glulam measuring 5 cm by 7 cm by 160 cm in thickness, width, and length, respectively, was made with three to five lamina, or layers, and isocyanate adhesive. The glulams contained either the same wood species for all layers or a combination of mangium face and back layers with a core layer of manii or sengon. Solid wood samples of the same size for all three species were included as a basis for comparison. Physical-mechanical properties and delamination tests of glulam referred to JAS 234:2003. The results showed that the properties of same species glulam did not differ from those of solid wood, with the exception of the shear strength of glulam being lower than that of solid wood. Wood species affected glulam properties, but three- and five-layer glulams were not different except for the modulus of elasticity. All glulams were resistant to delamination by immersion in both cold and boiling water. The glulams that successfully met the JAS standard were three- and five-layer mangium, five-layer manii, and five-layer mangium-manii glulams.

• Journal of Food Hygiene and Safety
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• v.31 no.1
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• pp.42-50
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• 2016

The effects of freezing and thawing conditions on microbiological quality and microstructure change of inoculated (Listeria monocytogenes and Campylobacter jejuni) and non-inoculated chicken breasts were investigated. Chicken breasts were frozen with air blast freezing (-20, -70, and $-150^{\circ}C$), ethanol ($-70^{\circ}C$) and liquid nitrogen ($-196^{\circ}C$) immersion freezing. There were no significant differences on the populations of L. monocytogenes inoculated with chicken breasts under different freezing conditions. However, air blast freezing ($-20^{\circ}C$) resulted in significant reductions for total aerobic bacteria and C. jejuni compared to the control and other freezing treatments. The frozen samples were thawed with (hot or cold) air blast, water immersion, and high pressure thawing at $4^{\circ}C$ and $25^{\circ}C$. the populations of total aerobic bacteria, and yeast and mold in the frozen chicken breast increased by 5.78 and 4.05 log CFU/g after water immersion thawing ($25^{\circ}C$) treatment. After five freeze-thaw cycles, the populations of total aerobic bacteria, yeast and mold, and C. jejuni were reduced by 0.29~1.40 log cycles, while there were no significant differences (P > 0.05) in the populations of L. monocytogenes depending on the freeze-thaw cycles. In addition, the histological examination of chicken breasts showed an increase in spacing between the muscle fiber and torn muscle fiber bundles as the number of freeze-thaw cycles increased. These results indicate that freezing and thawing processes could affect in the levels of microbial contamination and the histological change of chicken breasts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.261-268
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• 2018

The use of electric cable was limited due to the installation time and large space as the increase of power demand and load quantity in side line. In order to solve these problems, the application of busway system which can supply the large current was increasing. But it was lack of methods of performance tests to evaluate the reliability and results of test for busway system. In this paper, we presented items to evaluate the reliability test for epoxy coated busway system with reference to IEC 61349-6. In addition, we proposed items to evaluate the reliability and long term life cycle test for the epoxy coated busway system. The combined acceleration deterioration test that reflects actual conditions of the survey as much as possible was conducted considering both thermal and electrical stresses. The deterioration condition was selected to satisfy fifty years life expectation and the insulation performance verification test of the busway system confirmed the long term life prediction. Furthermore, as test items for reliability assessment of compliance with the environment for the use of temperature, humidity and load current where busway system was installed, thermal overload test, water immersion test, cold shock temperature test and thermal cycle test were performed. And we examined changes in characteristics and abnormality after tests. From results, the test items presented to evaluate performance and reliability of the epoxy insulated busway system were confirmed to be appropriate in this paper, and the performance of the product was also confirmed to be excellent for reliability tests.

• Korean Journal of Food Science and Technology
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• v.49 no.5
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• pp.502-506
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• 2017

To improve the storage and firmness of Tteokbokki tteok Korean-style rice cakes with spicy sauce, steaming of the rice dough, soaking of the rice cake in acidic solution, and heat sterilization were conducted sequentially. The untreated control could be stored for 1 month under cold conditions, but this was extended to 10 months at room temperature ($15-30^{\circ}C$) after immersion in lactic acid solution (pH 4.0) for 20 min and heating to $100^{\circ}C$ for 30 min. The mechanical strength, which was related to firmness, was significantly increased to $11.4kgm/s^2$ compared with the untreated rice cakes ($8.8kgm/s^2$, p<0.05) and the overall descriptions of the sensory evaluation, including texture, was significantly higher than the control (p<0.05). The average size of the pores in the treated rice cakes was smaller than that of the conventional sample and the texture was improved as a result of decreased starch elution from smaller pores.

• Journal of Acupuncture Research
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• v.23 no.5
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• pp.23-29
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• 2006

Objectives : The present study was conducted to evaluate the effects of automatically controlled rotating acupuncture (ACRA) on thermal allodynia in neuropathic pain rats, and to examine whether the endogenous opioid system mediates the effects of ACRA. Methods : For the neuropathic surgery, the right superior caudal trunk was resected at the level between S1 and S2 spinal nerves innervating the tail. Two weeks after the nerve injury, ACRA stimulation with 4 different stimulation conditions (i.e., angle and frequency of rotation: 90o+1Hz, 90o+1/4Hz, 360o+/1Hz, and 360o+1/4Hz) was delivered to the Zusanli (ST36) acupoint for 15 min. The behavioral signs of thermal allodynia were evaluated by the tail immersion test (i.e., immersing the tail in cold $(4^{\circ}C)$ or warm $(4^{\circ}C)$ water and measuring the latency to an abrupt tail movement) before and after the stimulation. In an additional set of experiments, we examined the effects of naloxone (opioid Results : ACRA stimulations under all of the conditions above significantly relieved thermal antagonist, 2mg/kg, i.p.) on the action of ACRA stimulation. allodynia. There is no difference in the anti-allodynic effects among the 4 stimulation conditions. In addition, the effect of ACRA on thermal allodynia was reversed by naloxone pretreatment. Conclusion : These results indicate that ACRA stimulations have relieving effects on thermal allodynia in neuropathic pain rats, irrespective of stimulation parameters, and that this is mediated by the endogenous opioid system.

• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.530-545
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• 1996

The purpose of this study was to investigate by spectrophotometry the changes in color parameters of composite resins after exposure to distilled water, filtered coffee, and artificial saliva. Five kinds of fine particle composite resin in experiment 1, and six kinds of composite resin in experiment 2 were used. In experiment 1, each group of composite resin was stored in distilled water at $4^{\circ}C$, $50^{\circ}C$, and filtered coffee solution at $4^{\circ}C$, $50^{\circ}C$. And then each specimen was measured by spectrophotometer. Measurements were repeated in 1 hour, 2 hours, 4 hours, 8 hours, 16 hours, 24 hours, and 48 hours. In experiment 2, all specimens of each brand were stored in distilled water at $37^{\circ}C$, artificial saliva not contained mucin at $37^{\circ}C$, and artificial saliva contained mucin at $37^{\circ}C$. All specimens of each brand were measured by spectrophotormeter in 1 week, 2 weeks, 4 weeks, 8 weeks, and up to 12 weeks. The results were as follows : 1. In cold coffee, five of fine particle composite resins showed ${\Delta}E{^*}_{ab}$ values less than 2. However, in hot coffee ${\Delta}E{^*}_{ab}$ values of Amelogen Universal and Prisma TPH were higher than those of Conquest Crystal, ${\AE}$litefil and Z100. 2. Z100 and ${\AE}$litefil had better cleansibility of extrinsic coffee staining than Amelogen Universal, Conquest Crystal and Prisma TPH. 3. In distilled water and artificial saliva not contained mucin, five of fine particle composite resin showed ${\Delta}E{^*}_{ab}$ values less than 2 up to 12 weeks. However, Silux Plus showed higher than ${\Delta}E{^*}_{ab}$ values of fine particle composite resin. 4. As an immersion solution for discoloration experiment, artificial saliva not contained mucin showed similar appearance as distilled water. However, artificial saliva contained mucin had different appearance from the others. 5. In artificial saliva contained mucin, ${\AE}$litefil, Prisma TPH and Z100 showed ${\Delta}E{^*}_{ab}$ values less than 1 up to 12 weeks. However, Silux Plus, Amelogen Universal and Conquest Crystal showed ${\Delta}E{^*}_{ab}$ values more than 1 up to 12 weeks. But, Conquest Crystal showed different characteristics of chromacity difference value(less chromatic) and lightness difference value(lighter) from Silux Plus and Amelogen Universal.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.95-95
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• 2022

Maize is one of the world's three largest crops and has a long cultivation history, and is an important crop used for various purposes such as food, feed, and industrial raw materials. Recently, the agricultural environment is changing, in which the limit of cultivation of crops is shifted to the north due to the rise in temperature due to climate change. This study was conducted in experimental field of Suwon in 2022 by setting a seeding period earlier than the sowing time to establish the North Korean agricultural climatic zone and meteorological conditions. The test cultivars were silage cultivars, Kwangpyeongok and Dacheongok. As a priming test method, it was used to directly plant seeds in the field through immersion using 4mM zinc (Zn) and 2.5mM manganese (Mn), which are trace elements for seeds. The planting season was early on March 15th, April 1st, and April 15th. The number of days from sowing to silk stage of the two cultivars sown on March 15, April 1, and April 15 was 107, 93, and 85 days for Kwangpyeongok and 109, 95, and 87 days for Dacheongok, respectively. The seed priming test did not show any difference from the control group in the growth survey up to the middle stage of growth. In another test, low-temperature recovery was confirmed through nitrogen (2-5%) foliar fertilization after 3 days, 5 days, and 7 days in refrigeration (0 degrees), a selective low temperature treatment for com in the third leaf stage. As a result of this study, it was confirmed that the low-temperature damaged com treated at 0℃ showed the same growth as that of the untreated com through nitrogen foliar fertilization. These results suggest that urea foliar fertilization for low-temperature damage reduction of corn for silage in high-latitude climates will be helpful. In addition, through the results of the study, additional studies are needed on the recovery mechanism and field application through urea foliar fertilization.