• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.6
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• pp.618-629
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• 2001

This paper presents a result of failure analysis and reliability evaluation for high voltage ceramic capacitors. The failure modes and failure mechanisms were studied in two ways in order to estimate component life and failure rate. The causes of failure mechanisms for zero resistance phenomena under withstanding voltage test in high voltage ceramic capacitors molded by epoxy resin were studied by establishing an effective root cause failure analysis. Particular emphasis was placed on breakdown phenomena at the ceramic-epoxy interface. The validity of the results in this study was confirmed by the results of accelerated testing. Thermal cycling test for high voltage ceramic capacitor mounted on a magnetron were implemented. Delamination between ceramic and epoxy, which might cause electrical short in underlying circuitry, can occur during curing or thermal cycle. The results can be conveniently used to quickly identify defective lots, determine $B_{10}$ life estimation each lot at the level of inspection, and detect major changes in the vendors processes. Also, the condition for dielectric breakdown was investigated for the estimation of failure rate with load-strength interference model.

• Journal of Food Hygiene and Safety
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• v.22 no.3
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• pp.159-164
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• 2007

The viable cell of 60% drinking water among 25 drinking water served in restaurant of Daegu district showed above 100 CFU/mL which is sanitary standard of drinking water. The 50 CEO of restaurant considered drinking water served in their own restaurant as just safe and were very deficient in aware of sanitation about drinking water. Sensory quality of drinking water boiled with plant materials, such as barley, Cassia semen, corn, Buckwheat, Korean solomon's seal, Chamomile, Brown rice-green and peppermint was improved in color, taste, flavor and overall acceptability compare to marketed drinking water, respectively. Especially drinking water boiled with Korean solomon's seal was the best In overall acceptability. The number of total bacteria reached above $10^2 CFU/mL$ in marketed drinking water after 4 days storage at 10. But the growth of microorganism did not occur in boiled drinking water with Brown rice-green tea, Korean solomon's seal, barley, Cassia semen and com during storage for 10 days at $10^{\circ}C$, respectively. The number of total bacteria reached above $10^2 CFU/mL$ in marketed drinking water after storage for 1 days at $25^{\circ}C$. The growth of microorganism was accelerated in boiled drinking water with corn, Korean solomon's seal, barley, Cassia semen except Brown rice-green tea during storage far 10 days at $25^{\circ}C$, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.11 no.3
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• pp.21-27
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• 1982

A kinetical approach for the non-enzymatic browning reaction of the dried file-fish was studied. The reaction rates revealed a tend to increase with increasing water activity and showed the maximum at $0.75\;a_w$ The activation energies obtained from the Arrhenius plot ranged 12.5 to 16.5 Kcal/mole. From these energies of activation, the $Q_{10}$ values at $45^{\circ}C$ showed 1.9 to 2.3 and both activation energy and $Q_{10}$ values were reduced with increase in $a_w$ Shelf-lives, the time to reach an 0.15 O.D./g solid at which severe brown color change could be de ectable, decreased rapidly as the temperature and water activity increase. A storage study under a square-wave fluctuating temperature condition (at 35 and $55^{\circ}C$ periodically with 7 days interval), the rate constants at all water activities used in the experiments were higher than those at $45^{\circ}C$, the mean temperature of the cycle which affects other kinetic parameters including activation energies, $Q_{10}$ values and finally the shelf-lives. The data obtained from the fluctuating temperaure storage study will be used in prediction of shelf-life. The shelf lives assessed at $25^{\circ}C$ from the accelerated shelf-life tests ranged from 179 daysat $0.75\;a_w$ to 302 days at $0.44\;a_w$.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.6
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• pp.1643-1651
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• 2004

This experimental study was designed to investigate the effects of SIEGESBECKIAE HERBA extract (SHE) on the change of cerebral hemodynamics 〔regional cerebral blood flow (rCBF) and mean arterial blood pressure(MABP)〕 in normal condition and cerebral ischemic rats, and to determine the mechanism of action of SHE. This study was designed to investigate whether or not SHE inhibit lactate dehydrogenase (LDH) activity in neuronal cells and cytokines production in serum of cerebral ischemic rats. The results were as follows SHE increased rCBF significantly in a dose-dependent manner, but MABP was not changed by SHE in normal rats. The SHE-induced increase in rCBF was significantly inhibited by pretreatment with indomethacin (IDN), an inhibitor of cyclooxygenase but was increased by methylene blue (MTB), an inhibitor of guanylate cyclase. SHE inhibited lactate dehydrogenase (LDH) activity significantly in neuronal cells. rCBF was increased significantly and stably by SHE(10㎎/㎏, i.p.) during the period of cerebral reperfusion, which contrasted with the findings of rapid and marked increase in control group in ischemic rats. In serum by drawing from femoral arterial blood after middle cerebral arterial occlusion(MCAO) for 1hr and reperfusion for 1hr, the sample group was decreased IL-1β production significantly compared to that of the control group. In serum by drawing from femoral arterial blood after MCAO 1hr and reperfusion 1hr, sample group decreased TNF-α production significantly compared to that of the control grolilp. In serum by drawing from femoral arterial blood after reperfusion 1hr, sample group increased TGF-β production significantly compared to that of the control group. In serum by drawing from femoral arterial blood after MCAO for 1hr and reperfusion for 1hr, IL-10 production of the sample group was similar to that of control group. These results suggested that SHE had inhibitive effect on the brain damage by inhibited LDH activity, IL-1β and TNF-α production, but accelerated TGF-β production.

• Research in Plant Disease
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• v.17 no.3
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• pp.381-385
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• 2011

Effects of temperatures, relative humidity, pH, and dry periods on conidial germination of Alternaria dauci were evaluated under in vitro conditions. Conidial germination was accelerated at over 95% relative humidity in $15^{\circ}C$ to $25^{\circ}C$ condition. Conidial germination was rapidly reduced at 5 regardless of relative humidity conditions. More than 50% of the conidial germination were initiated within 2 h at $25^{\circ}C$ through pH 5 to 7. The highest conidial germination of A. dauci was on 0.2% of carrot leaf extract. Conidia could survive longer than 12 h, even though its germination decreased. After a 12 h dry period, around 10% of conidia revived and germinated when conidia were hydrated again. These results could be used as the useful information on conidial germination of A. dauci and ecology of Alternaria leaf blight.

• Journal of Korean Society of Steel Construction
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• v.28 no.5
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• pp.373-382
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• 2016

Painting or thermally sprayed metal coating is often used in corrosion protection of steel structures. In recently, duplex coating system which combines thermally sprayed metals with paint is selected as a new generic type of coatings on steel structures under the highly corrosive environments. In this study, the structural steel specimens were surface treated, thermally sprayed with zinc, zinc-15%aluminum alloy, aluminum and aluminum-5%magnesium alloy, and finally sealing or painted with acrylic urethane. And as a reference specimens, steel specimens were painted with acrylic urethane after surface treatment. Circular defects with 1.0, 3.0 and 5.0 mm in diameters and line defect with 2.0 mm width, which reach the steel substrate were created on all specimens. The specimens were exposed into an environmental testing chamber controlled by the ISO 20340, which is a laboratory cyclic accelerated exposure test condition of spraying/UV/low temperature, for up to 175 days. Based on the corrosion tests, corrosion deterioration from the initial defects were evaluated and weathering performance of the specimens are compared.

• Journal of the Korean Wood Science and Technology
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• v.34 no.6
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• pp.44-50
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• 2006

To characterize thermo-chemical feature of su gar conversion of woody biomass poplar wood (Populus alba${\times}$glandulosa ) by sub- and supercritical water was treated for 60s under subcritical (23 MPa, 325 and $350^{\circ}C$) and supercritical (23 MPa, 380, 400, and $425^{\circ}C$) conditions, respectively. Among degradation products undegraded poplar wood solids existed in aqueous products. As the treatment temperature increased, the degradation of poplar wood was enhanced and reached up to 83.1% at $425^{\circ}C$. The monomeric sugars derived from fibers of poplar wood by sub- and supercritical treatment were analyzed by high performance anionic exchange chromatography (HPAEC). Under the subcritical temperature ranges, xylan, main hemicellulose component in poplar wood, was preferentially degraded to xylose, while cellulose degradation started at the transition zone between sub and supercritical conditions and was remarkably accelerated at the supercritical condition. The highest yield of monomeric sugars amounts to ca. 7.3% based on air dried wood weight (MC 10%) at $425^{\circ}C$.

• Archives of design research
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• v.16 no.4
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• pp.313-322
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• 2003

The residential and welfare facilities for the elderly are continuously increasing due to change of value on family under situation of aging population increase. And it is predicted that accommodation capacity of facilities for the elderly and its rate those facility takes compared to whole social welfare facilities will be accelerated considering past increase speed. On the other hand, about 60％ of elderly people have low physical and mental level almost dose to handicapped people therefore special environmental concerns helping their independent living are necessary. The purpose of this study is to analyze whether facilities for the elderly are adequate to accommodate their request condition by understanding color among environmental factors is one of most important factor for smooth understanding, communication and psychological remedy effect for thou. For this purpose, importance and effect of color and visual characteristic and reaction to color in elderly environment are researched through documents and visited 10 facilities in Seoul and Kyunggi region to research interior color status. And measuring of color on 5 main spaces of the facilities such as lobby/lounge, corridor, dining room, bedroom, stairway/ramp are done under analysis of its functional and aesthetic level based on Moon ＆ Spencer's color theory.

• The Korean Journal of Mycology
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• v.36 no.1
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• pp.45-50
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• 2008

This study was carried out to investigate the promoting effect of wood flour on the mycelial growth of Lentinus lepideus and Lentinus edodes. To determine the optimal culture condition, we first examined the tissue origin of pine flour (Pinus densiflora) including needle, bark, root and xylem. Only the xylem-derived flour increased mycelial growth compared to no treatment control. The addition of the xylem flour (5 g/l) showed the highest increase and the glucose level in the basal medium was best at 10 g/l. The smaller particle size of the xylem flour showed the positive effect on mycelial growth; two-fold increase when supplemented with flour of which particle size is less than $106\;{\mu}m$ in diameter compared to $425\;{\mu}m$. The addition of the xylem flour continuously increased the mycelial production for 25 days while mycelia stopped growing within 15 days without the xylem flour. In addition, when woody flour obtained from the different tree species was applied to L. edodes mycelial culture, all treatments accelerated mycelial production compared to the control. Based on all results described above, we conclude that the supplementation of woody flour to culture medium may be an another promising way to increase mycelial production of economically important fungi.

• International Journal of Highway Engineering
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• v.20 no.3
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• pp.1-9
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• 2018

PURPOSES : In order to evaluate a crack resistance at cold joint, sealing tape was adopted to apply at cold joint instead of typical tack coat material(RSC-4). The sealing tape was made by hot sealing material. The crack resistance as function of environmental and traffic loading was measured with visual observation. METHODS : In this study, the crack resistance was evaluated as function of environmental and traffic loading. The freeze-thaw method was adopted for environmental loading of asphalt pavement. condition. The damage of cold joint under freeze-thaw action is initiated by ice expansion load and accelerated by the interfacial damage between new and old asphalt pavement. The traffic loading was applied with wheel tracking machine on the cold joint area of the asphalt pavement for 3 hours at $25^{\circ}C$. The evaluation of crack resistance was measured with visual observation. The freeze-thaw results shows that the sealing tape was significantly increased the crack resistance based on. RESULTS : To estimate the crack resistance at cold joint area due to the environmental loading, the Freeze-thaw test was conducted by exposing the product to freezing temperature(approximately $-18^{\circ}C$) for 24 hours, and then allowing it to thaw at $60^{\circ}C$ for 24 hours. The tack coat material(RSC-4) was debonded after 21 cycles of the Freeze-thaw test. The first crack was observed after 14 freeze-thaw cycle with RSC-4 material. But, the sealing tape was not debonded after 24 cycle test. Also, the sealing tape shows the better performance of the crack resistance under the traffic loading with wheel track test. The crack was generated the under traffic loading with RSC-4(tack coating), however, the crack was not shown with sealing tape. It indicates that the sealing tape has a strong resistance of tensile stress due to traffic loading. CONCLUSIONS :Based on limited laboratory test result, a performance of crack resistance using the sealing tape is better than that of general tack coat material(RSC-4). It means that the sealing tape is possible to extend a pavement service life because the crack, one of the main pavement distresses, will be delayed.