• Korean Journal of Materials Research
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• v.11 no.11
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• pp.991-996
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• 2001

This study is the manufacture of solid lubricant oilless bearing using sintered parts. PTFE was as organic solid lubricant and $MoS_2$ as inorganic solid lubricant, and its characteristics were studied. Thickness of lubricant was suited 25~$100\mu\textrm{m}$ for lubricant characteristics. Curring temperature of MoS_2$ film was 12$0^{\circ}C$, 2 hours and that of PTFE film was $260^{\circ}C$, 20 minutes. The solid weight and solid volume of $MoS_2$ film was 51.7% and 27.4%, and that of PTFE was 44.9% and 24.3%. Chemical resistant of PTFE solid lubricant oilless bearing was excellent as salt test was 520hours, and usable temperature range was $-200~+280 ^{\circ}C$. Conduction of electricity can be increase by addition of graphite or $$\alpha$- PbO_2$. The electric conductivity was 100~180$\Omega$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1991.10a
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• pp.12-16
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• 1991

Cadmium sulphide films with thickness of 0.6∼1.2$\mu\textrm{m}$ were deposited onto corning 7059 glass substrate under a vacuum of 5${\times}$10$\^$-6/ Torr. Source and substrate temperature ranges used were 800∼1100$^{\circ}C$ and 100∼200$^{\circ}C$, respectively. The microstructures and semiconducting properties of the films were studied using X-ray diffraction, UV-VIS-IR spectrophotometer and Hall measurement unit. Electrical resistivity and optical transmission of the CdS films decrease with an increase in source temperature while they increase with an increase in substrate temperature. The resistivity of the film evaporated at 1100$^{\circ}C$ varied from 7${\times}$10$^3$ohm-cm at the substrate temperature of 100$^{\circ}C$ to 2${\times}$10$\_$6/ohm-cm at 190$^{\circ}C$. All the films had hexagonal structure and strong texture with c-axis of grains normal to the substrate glass.

• Journal of Soil and Groundwater Environment
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• v.11 no.2
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• pp.13-21
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• 2006

Polycyclic aromatic hydrocarbons (PAHs) are widespread soil contaminants and major environmental concerns. PAHs have extremely low water solubility and are strongly sorbed to soil. A potential technology for remediation of PAHcontaminated soils is a soil washing with surfactant solutions. While the use of surfactants significantly enhances the performance of soil remediation, operation costs are increased. Selective adsorption of PAHs by activated carbons is proposed to reuse the surfactants in the soil-washing process. The adsorption isotherms of pure chemicals (Triton X-100 and phenanthrene) onto three granular activated carbons were obtained. The selective adsorption of phenanthrene in mixed solution was examined at various concentrations of phenanthrene and Triton X-100. The selectivity results were discussed with pore size distribution of activated carbons and molecular sizes of phenanthrene and the Triton X-100 monomer. The selectivity for phenanthrene was much larger than 1 regardless of the particle size of activated carbons. The selective adsorption using activated carbons with proper pore size distribution would greatly reduce the material cost for the soil washing process by the reuse of the surfactants.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.4
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• pp.387-392
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• 1997

This paper describes a combination surge generator for carrying out performance tests on the surge protection circuits of shipboard electrical systems. Pspice simulations were performed to decide the values of the parts required and to analyze the characteristics of the generator circuitry. The surge generator fabricated can produce four of the most common surge test waveforms : the O.5i/S/100kHz Ringwave, the 1.2/50$\mu$S voltage, the 8/20$\mu$S current, and the lO/lOOOi/S voltage wave¬forms specified in ANSI Std. C62. Source impedances of the surge generator are 12$\Omega$ in the O.5$\mu$S/100kHz mode, O.5$\Omega$ in the 1.2/50$\mu$S and 8/20$\mu$S mode, and 40$\Omega$in the l0/1000$\mu$S mode, and are determined by the ratio of the maxi¬mum open - circuit voltage to the maximum short - circuit current. Experimental results show that the surge generator provides most of the outputs required for the testing of the surge protection circuits on shipboard electrical systems.

• Journal of the Korean Institute of Gas
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• v.19 no.2
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• pp.12-19
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• 2015

$CO_2$ is non-flammable, non-toxic gas and not cause of chemical explosion. However, various impurities and some oxides can be included in the captured $CO_2$ inevitably. While the $CO_2$ gas was temporarily stored, the pressure in a storage tank would be reached above 100bar. Therefore, the tank could occur a physical explosion due to the corrosion of vessel or uncertainty. Evaluating the intensity of explosion can be calculated by the TNT equivalent method generally used. To describe the physical explosion, it is assumed that the capacity of a $CO_2$ temporary container is about 100 tons. In this work, physical explosion damage in a $CO_2$ storage tank is estimated by using the Hopkinson's scaling law and the injury effect of human body caused by the explosion is assessed by the probit model.

• Journal of the Korean Society of Radiology
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• v.14 no.6
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• pp.741-746
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• 2020

To investigate the radiation dose sensitivity in extremity radiatioin therapy depending on rice cultivar which have different size and shape of grains, plan results are compared that used rice bolus Korean and Thai rice. Phantoms that are each no bolus, Korean rice bolus, Thai rice bolus were used and prescribed 100 cGy to isocenter and checked the point dose of 12 points of interest of each phantoms. The meane dose are 103.57±1.98 cGy in Thai rice bolus using, 104.27±2.12 cGy in Korean rice bolus and 104.99±6.40 cGy in phantom without bolus. Dose distribution of Thai and Korean rice bolus differed significantly in Wilcoxon's Signed Rank test (p=.011). It has been confirmed that that the bolus using Thai rice, which has a small grain size, shows a more even dose distribution.

• The Journal of the Korea Contents Association
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• v.15 no.12
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• pp.294-303
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• 2015

The purpose of this study was to examine the effects end-of-life care education using self-reflection diary on spirituality, death orientation, and attitudes toward nursing care of the dying patients in nursing students. This study adopted nonequivalent control group pretest-posttest design and the subjects consisted of 69 in the experimental group and 68 in the control group. The education was performed for 100 minutes a session, once a week for 12 weeks. Data was collected using a structured questionnaire consisting of general characteristics, spirituality, death orientation, and attitudes toward nursing care of the dying patients. Collected data was analyzed for frequency, percentage, ${\chi}^2$ test, Fisher's exact test and t-test using SPSS/WIN 21.0 computed program. There were statistically significant differences in spirituality and attitudes toward nursing care of the dying patients between the experimental group and the control group. Regarding death orientation, our result showed no significant differences between two groups. These findings suggest that end-of-life care education using self-reflection diary was effective in enhancing the spirituality and attitudes toward nursing care of the dying patients in nursing students.

• Fisheries and Aquatic Sciences
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• v.23 no.9
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• pp.21.1-21.10
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• 2020

Background: This study aimed to provide a basic standard for assessing freshness and acceptability of whiteleg shrimp (Litopenaeus vannamei). Methods: It was divided into whole body and meat and stored at 25 ℃ to evaluate both quality and freshness changes that occur over time. The shelf life of shrimp was estimated as 17 and 20 h for whole body and meat, respectively. Results: In chemical analysis, K-value increased from 9.96 to 12.32% to a maximum of 75.14%, and TVB-N increased from 1.86 mg/100 g to 34.71 mg/100 g. For volatile sulfur compounds, methyl mercaptan and dimethyl disulfide increased from 0.00 mg/100 g to 1.10 mg/100 g and 1.26 mg/100 g, respectively, rapidly increasing with decreasing freshness. Conclusion: Changes in all biochemical indicators significantly correlated with the sensory evaluation results. This study contributes to the knowledge about whiteleg shrimp spoilage and freshness, providing a basis for developing methods to improve shrimp quality control and management.

• Korean Journal of Poultry Science
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• v.45 no.3
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• pp.193-200
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• 2018

The purpose of this study was to evaluate the influence and safety of spraying Farm Clean-S (FC-S) containing 70% Chamaecyparis obtusa essential oil on the elimination of red mite in laying hens. In total, 300 laying hens (ISA brown) aged 72 weeks and infected with red mite were assigned to individual cages for five treatments with five replicates for 18 days. Treatments consisted of distilled water (negative control; NC), commercial spray product (positive control; PC), FC-S 0 (original concentration), FC-S 50 (50 times diluted) and FC-S 100 (100 times diluted). The number of red mites, egg production and weight of each group were evaluated daily throughout the whole experimental period. Egg quality and blood biochemical parameters were measured at the end of the experiment. Safety tests were confirmed by feed intake, respiration, lethargy, diarrhea and mortality symptoms after the feeding trial. As the result, more than 80% of red mites were eliminated by the FC-S 0 spray treatment, and FC-S 50 also showed a higher elimination percentage than did PC (P<0.01). However, the elimination effect of the FC-S 100 spray was lower than that of the PC, but higher than that of the NC (P<0.01). These results confirmed that the optimum FC-S dilution rate ranged from 0~50 times with distilled water to eliminate the red mite effectively. The performance, egg quality, blood parameter and safety tests were not significantly different among treatments. Thus, FC-S 0 and FC-S 50 spray treatments can effectively and sustainably control red mite infestations without detrimental effects on the performance, egg quality and plasma biochemical properties of laying hens.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.400-406
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• 2018

In this experiment the effect of supplemental lighting on the growth and yield of cucumber (Cucumis sativus L. 'Fresh') plants during low radiation period of winter season were investigated in glasshouses using common high-pressure sodium (HPS) lamps and newly developed plasma lighting system (PLS) lamps. Plants grown without supplemental lighting were considered as a control. Supplemental lighting was provided from November 20th, 2015 to March 15th, 2016 to ensure 14-hour photoperiod (natural+supplemental light), also lamps were operated automatically when the outside sun radiation levels were less than $100W{\cdot}m^{-2}$. Spectral analysis showed that HPS lamp had a discrete spectrum, lacked of the radiation in the 400-550 nm wave band (blue-green light), but had a high output in the orange-red region (550-650 nm). A higher red light output resulted in an increased red to far-red (R/FR) ratio in HPS lamp. PLS had a continuous spectrum and had a peak radiation in green region (490-550 nm). HPS has 12.6% lower output in photosynthetically active radiation (PAR) but 12.6% higher output in near infra-red (NIR) spectral regions compared to PLS. Both HPS and PLS lamps emitted very low levels of ultra-violet radiation (300-400 nm). Supplemental lighting both from HPS and PLS lamps increased plant height, leaf number, internode number and dry weight of cucumber plants compared to control. Photosynthetic activity of cucumber plants grown under two supplemental lighting systems was comparable. Number of fruits per cucumber plant (fruit weight per plant) in control, PLS, and HPS plots were 21.2 (2.9 kg), 38.7 (5.5 kg), and 40.4 (5.6 kg), respectively, thereby increasing yield by 1.8-1.9 times in comparison with control. An analysis of the economic feasibility of supplemental lighting in cucumber cultivation showed that considering lamp installation and electricity costs the income from supplemental lighting increased by 37% and 62% for PLS and HPS lamps, respectively.