• Asian-Australasian Journal of Animal Sciences
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• v.24 no.12
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• pp.1711-1717
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• 2011

The objective of this experiment was to evaluate the effect of dietary supplementation of glutathione (GSH) on health, solid feed consumption, nutrient intake, body weight gain (BWG), feed efficiency, blood metabolites and the occurrence of diarrhea in Holstein neonatal calves. The calves were fed plain milk as a control (CON) or milk with GSH supplementation. Sixteen calves were separated from their mothers immediately after birth, moved into individual cages and fed colostrum for the first three days. For GSH supplementation, three grams of GSH powder were mixed in 1.8 L of heat-treated milk and placed in a plastic bottle with a rubber nipple. The calves were fed GSH-supplemented milk only once out of four daily feedings. For the first 25 d, calves were fed 1.8 L of milk four times per day. Milk feeding frequency was reduced to three times per day from days 26 to 30, followed by twice a day from days 31 to 44, and once a day from days 45 to 49, after which they were weaned at day 50. Body weight gain (BWG), feed consumption, and growth performance were monitored until day 70. The dietary supplementation of GSH had no effect on daily feed intake and growth performance in growing calves. Hematological results revealed red blood cell distribution width (RDW) was lower, and mean corpuscular volume (MCV) was significantly higher in calves fed GSH. Serum lactate dehydrogenase (LDH) concentrations were lower in calves fed GSH. Rectal temperature at day 70 was higher in calves that did not receive GSH, while mean frequency of diarrhea and enteritis was less in calves fed GSH. It is concluded from the present study that BW gain, total dry matter intake (DMI), feed efficiency, and breathing rate did not differ between groups. However, there were some positive blood parameters and the mean frequency of diarrhea and enteritis was less in calves fed GSH compared to CON which did not receive GSH. With the results obtained, supplementation of GSH is highly recommended.

• Korean Journal of Materials Research
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• v.30 no.6
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• pp.292-300
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• 2020

In this study, the effect of tempering on the stretch-flangeability is investigated in 980 MPa grade dual-phase steel consisting of ferrite and martensite phases. During tempering at 300 ℃, the strength of ferrite increases due to the pinning of dislocations by carbon atoms released from martensite, while martensite is softened as a consequence of a reduction in its carbon super-saturation. This strength variation results in a considerable increase in yield strength of the steel, without loss of tensile strength. The hole expansion test shows that steel tempered for 20 min (T20 steel) exhibits a higher hole expansion ratio than that of steel without tempering (T0 steel). In T0 steel, severe plastic localization in ferrite causes easy pore formation at the ferrite-martensite interface and subsequent brittle crack propagation through the highly deformed ferrite area during hole expansion testing; this propagation is mainly attributed to the large difference in hardness between ferrite and martensite. When the difference in hardness is not so large (T20 steel), on the other hand, tempered martensite can be considerably deformed together with ferrite, thereby delaying pore formation and hindering crack propagation by crack blunting. Eventually, these different deformation and fracture behaviors contribute to the superior stretch-flangeability of T20 steel.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.157-157
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• 2015

Recently, the growing interest in organic microelectronic devices including OLEDs has led to an increasing amount of research into their many potential applications in the area of flexible electronic devices based on plastic substrates. However, these organic devices require a gas barrier coating to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency OLEDs require an extremely low water vapor transition rate (WVTR) of $1{\times}10^{-6}g/m^2day$. The Key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required ($1{\times}10^{-6}g/m^2day$) is the suppression of defect sites and gas diffusion pathways between grain boundaries. In this study NBAS process was introduced to deposit enhanced film density single gas barrier layer with a low WVTR. Fig. 1. shows a schematic illustration of the NBAS apparatus. The NBAS process was used for the $Al_2O_3$ nano-crystal structure films deposition, as shown in Fig. 1. The NBAS system is based on the conventional RF magnetron sputtering and it has the electron cyclotron resonance (ECR) plasma source and metal reflector. $Ar^+$ ion in the ECR plasma can be accelerated into the plasma sheath between the plasma and metal reflector, which are then neutralized mainly by Auger neutralization. The neutral beam energy is controlled by the metal reflector bias. The controllable neutral beam energy can continuously change crystalline structures from an amorphous phase to nanocrystal phase of various grain sizes. The $Al_2O_3$ films can be high film density by controllable Auger neutral beam energy. we developed $Al_2O_3$ high dense barrier layer using NBAS process. We can verified that NBAS process effect can lead to formation of high density nano-crystal structure barrier layer. As a result, Fig. 2. shows that the NBAS processed $Al_2O_3$ high dense barrier layer shows excellent WVTR property as a under $2{\times}10^{-5}g/m^2day$ in the single barrier layer of 100nm thickness. Therefore, the NBAS processed $Al_2O_3$ high dense barrier layer is very suitable in the high efficiency OLED application.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.5
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• pp.451-469
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• 2002

The purpose of this study was to estimate the effect of a bleaching agent on tooth surfaces and to evaluate the resin bond strength according to different surface treatments on bleached teeth. To prepare for the experimental samples, first, extracted human third molars were used and the body portions of the crowns were cut into four equal-sized specimens. Next, each specimen was mounted in an plastic bottle with self-cured resin and highly polished to have them reveal the enamel or dentin surfaces. Then, the enamel(E) and dentin(D) specimens were divided into four ; 1) non-bleached, laser-treated(NBLA) group 2) bleached, laser-treated(BLLA) group 3) non-bleached, acid-treated(NBAC) group and 4) bleached, acid-treated(BLAC) group. Here, $opalescence^{(R)}$ (10% carbamide peroxide) was used for bleaching agent. The treated specimens were observed by confocal laser scanning microscopy and bonded with composite resin for shear bond test. The following results were obtained from this experiment : 1. Compared with the ENB group, the EBL group was shown be dyed about $20{\mu}m$ deeper with rhodamine B. The DBL group appeared to be caved in at the entry part of the dentinal tubules, was dyed about $20{\mu}m$ deeper and $5{\mu}m$ wider in diameter, compared with the DNB group. 2. In comparison with the EBLAC group, the ENBAC group looked evenly bonded with the resin, while the DNBAC group, compared to DBLAC group, was observed to have its resin tags penetrated about $50{\mu}m$ deeper. Other than those, however, no observable differences between ENBLA and EBLLA group or between DNBLA and DBLLA group were found. 3, At the shear bond test, the ENBAC group was shown to have statistically significant higher shear bond strength than the EBLAC group(p<0.05). No statistically significant differences between the ENBLA and the EBLLA groups were observed(p>0.05). 4. At the shear bond test, the DNBAC group was shown to have statistically significant higher shear bond strength than the DBLAC group(p<0.05). No statistically significant differences between the DNBLA and the DBLLA groups were observed(p>0.05). The in vitro observations above suggest that tooth-bleaching procedure brings a certain change on enamel and dentin surfaces and it weakens the shear bond strength with composite resin when the bleached tooth was acid-treated.

• The Journal of Engineering Geology
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• v.19 no.2
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• pp.177-189
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• 2009

The shear strength has been managed as an important factor in soil mechanics. The shear strength estimation model was developed to evaluate the shear strength using only a few soil properties by the linear regression analysis model which is one of the statistical methods. The shear strength is divided into two part; one is the internal friction angle (${\phi}$) and the other is the cohesion (c). Therefore, some valid soil factors among the results of soil tests are selected through the correlation analysis using SPSS and then the model are formulated by the linear regression analysis based on the relationship between factors. Also, the developed model is compared with the result of direct shear test to prove the rationality of model. As the results of analysis about relationship between soil properties and shear strength, the internal friction angle is highly influenced by the void ratio and the dry unit weight and the cohesion is mainly influenced by the void ratio, the dry unit weight and the plastic index. Meanwhile, the shear strength estimated by the developed model is similar with that of the direct shear test. Therefore, the developed model may be used to estimate the shear strength of soils in the same condition of study area.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.722-726
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• 2009

The residue distribution ratio of pesticides among the flesh, stem and leaves of hot peppers were investigated to assure the safety of pepper powder and pepper leaves. Mixed solutions of chlorothalonil (wettable powder), kresoximmethyl (water dispersible granules) and procymidone (wettable powder) were applied once onto pepper plants in a plastic film house. After 7 days, the fruits and leaves were harvested and the fruits were divided into the flesh and stems. Pesticide residues in each pepper part were then analyzed by gas chromatography. The results showed that the concentration ratios of the chemicals in the flesh:stem and flesh:leaf ranged from 1:2-5 and 1:11-39, respectively, depending on the chemical evaluated. The observed flesh:stem ratio indicates that the pesticide content of the pepper powder product can increase by 20% if pepper stems are included in the powder product. The Korea Food and Drug Administration does not set a pesticide maximum residue level (MRL) for pepper leaves if a residue ratio in leaves over flesh is more than ten times. Results from this study support non-MRL status on the pepper leaves for the studied pesticides. Additionally, we recommend that the chlorothalonil product of a wettable powder type include the phrase "prohibition of distribution or sale for pepper leaves as food" because chlorothalonil highly resided in pepper leaves as more than twenty-four times that is a criterion level to determine an inclusion of the phrase in the label of pesticide product.

• Research in Plant Disease
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• v.10 no.4
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• pp.324-330
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• 2004

This studies were investigated the occurrence of sclerotinia rot at the crisphead lettuce field in Uiryeong-Gun, Gyeongsangnam-Do from January to May in 2003. Average incidence rates of sclerotinia rot on crisphead lettuce was up to 21.9% at the five plastic houses. A total of 140 isolates of Sclerotinia sp. were obtained from diseased leaves of crisphead lettuce. Among them, the fungi YR-1 was isolated, which showed highly virulent on the whole plant. the YR-1 was identified as Sclerotinia sclerotiorum based on the formation, color, shape and size of sclerotium and apothecium. For the pathogenicity test, the most suitable inoculum quantity of YR-1 strain was selected as the triturated mycelial suspension of $A_{550}$=0.8, 40 ml showing disease incidence of 94%, and the symptom showed as same as at the fields, the leaves and stem had rotten and developed white downy mycelial at the diseased lesion on the leaves and stems, and produced black and irregular sclerotinia. This is the first report on the pathogenicity test using by triturated mycelial suspension-inoculum of the pathogen for the sclerotinia rot of crisphead lettuce.

• Journal of Energy Engineering
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• v.14 no.2 s.42
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• pp.159-166
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• 2005

In Korea, although the generation of waste plastic has been increasing, the rate of recycling is considerably low and moreover, there is no suitable method for the treatment of waste plastics. However, pyrolysis, which is appropriate for the treatment of highly polymerized compounds, such as plastics, has recently gained much interest. In this study, a property of the products from the pyrolysis of mixed waste plastics, with a possible practical use for the recycling oil produced, were assessed. First of all, in order to investigate the pyrolysis characteristic of waste plastics, TGA (Thermogravimetric analysis) and DCS (Differential Scanning Calorimetry) were performed on a number of different plastics, including PP, LDPE, HDPE, PET and PS, as well as others. According to the result, it appeared that PP was the most efficiently pyrolyzed by changing the temperature, followed by LDPE, HDPE, PET, PS and the other plastics, in that order. From the results, the optimum conditions f3r pyrolysis were set up, and the different waste plastics pyrolyzed. The recycling oil produced from the flammable gases generated during the pyrolysis was com-pared with fuel oil by an analysis using the petroleum quality inspection method on KS(Korea industrial Standard). The results of the analysis showed the recycling oil was of a similar standard to fuel oil, with the exception of the ignition point, with a quality somewhere between that of paraffin oil and diesel fuel. With respect to these results, the quality of the recycling oil produced by the pyrolysis of waste plastics was suf-ficient for use as fuel oil.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.3
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• pp.277-288
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• 2017

Previous studies of health effects of $PM_{2.5}$ performed spatial monitoring campaigns to assess spatial variability of $PM_{2.5}$ across people's residences. Highly reliable portable and cost-effective samplers will be useful for such campaigns. This study aimed to investigate applicability of the Deployable Particulate Impact Sampler(DPIS), one of the compact impact samplers, to spatial monitoring campaigns of $PM_{2.5}$ in Seoul, Korea. The investigation focused on the consistency of $PM_{2.5}$ concentrations measured by DPISs compared to those by the Low-volume Cyclone sampler (LCS). LCS has operated at a fixed site in the Seoul National University Yeongeon campus, Seoul, Korea since 2003 and provided qualified $PM_{2.5}$ data. $PM_{2.5}$ sampling of DPISs was carried out at the same site from November 17, 2015 through February 3, 2016. $PM_{2.5}$ concentrations were quantified by the gravimetric method. Using a duplicated DPIS, we confirmed the reliability of DPIS by computing relative precision and mean square error-based R squared value ($R^2$). Relative precision was one minus the difference of measurements between two samplers relative to the sum. For accuracy, we compared $PM_{2.5}$ concentrations from four DPISs (DPIS_Tg, DPIS_To, DPIS_Qg, and DPIS_Qo) to those of LCS. Four samplers included two types of collection filters(Teflon, T; quartz, Q) and impaction discs(glass fiber filter, g; pre-oiled porous plastic disc, o). We assessed accuracy using accuracy value which is one minus the difference between DPIS and LCS $PM_{2.5}$ relative to LCS $PM_{2.5}$ in addition to $R^2$. DPIS showed high reliability (average precision=97.28%, $R^2=0.98$). Accuracy was generally high for all DPISs (average accuracy=83.78~88.88%, $R^2=0.89{\sim}0.93$) except for DPIS_Qg (77.35~78.35%, 0.82~0.84). Our results of high accuracy of DPIS compared to LCS suggested that DPIS will help the assessment of people's individual exposure to $PM_{2.5}$ in extensive spatial monitoring campaigns.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.4
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• pp.106-113
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• 1997

Dynamic loading of structures often causes excursions of stresses well into the inelastic range, and the influence of the geometric changes on the dynamic response is also significant in many cases. Therefore, both material and geometric nonlinearity effects should be considered in case that a dynamic load acts on the structure. A structure in a nuclear power plant is a structure of importance which puts emphasis on safety. A nuclear container is a pressure vessel subject to internal pressure and this structure is constructed by a reinforced concrete or a pre-stressed concrete. In this study, the material nonlinearity effect on the dynamic response is formulated by the elasto-viscoplastic model highly corresponding to the real behavior of the material. Also, the geometrically nonlinear behavior is taken into account using a total Lagrangian coordinate system, and the equilibrium equation of motion is numerically solved by a central difference scheme. The constitutive relation of concrete is modeled according to a Drucker-Prager yield criterion in compression. The reinforcing bars are modeled by a smeared layer at the location of reinforcements, and the steel layer model under Von Mises yield criteria is adopted to represent an elastic-plastic behavior. To investigate the dynamic response of a nuclear reinforced concrete containment structure, the steel-ratios of 0, 3, 5 and 10 percent, are considered. The results obtained from the analysis of an example were summarized as follows 1. As the steel-ratio increases, the amplitude and the period of the vertical displacements in apex of dome decreased. The Dynamic Magnification Factor(DMF) was some larger than that of the structure without steel. However, the regular trend was not found in the values of DMF. 2. The dynamic response of the vertical displacement and the radial displacement in the dome-wall junction were shown that the period of displacement in initial step decreased with the steel-ratio increases. Especially, the effect of the steel on the dynamic response of radial displacement disapeared almost. The values of DMF were 1.94, 2.5, 2.62 and 2.66, and the values increased with the steel-ratio. 3. The characteristics of the dynamic response of radial displacement in the mid-wall were similar to that of dome-wall junction. The values of DMF were 1.91, 2.11, 2.13 and 2.18, and the values increased with the steel-ratio. 4. The amplitude and the period of the hoop-stresses in the dome, the dome-wall junction, and the mid-wall were shown the decreased trend with the steel-ratio. The values of DMF were some larger than those of the structure without steel. However, the regular trend was not found in the values of DMF.