• Journal of Industrial Convergence
• /
• v.18 no.5
• /
• pp.62-69
• /
• 2020

The purpose of this study was to investigate the relationship between serum vitamin E levels and the risk of allergic rhinitis among Koreans. This study is a secondary data analysis using big data from the seventh Korea National Health and Nutrition Examination Survey (KNHANES VII-3), which was conducted in 2018. Complex-sample descriptive statistics, t-test, ANOVA and odds ratio were used for data analysis in SPSS 25. The average serum vitamin E level among Koreans aged above 10 was 12.60 mg/L, and 15.9% had been diagnosed with of allergic rhinitis by a doctor. Lower serum vitamin E levels were significantly associated with the prevalence of allergic rhinitis (β=-0.05, p=.013). Therefore, efforts to prevent and manage allergic rhinitis among Koreans should incorporate regular monitoring of vitamin E level and ongoing research into antioxidants.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.4
• /
• pp.1663-1672
• /
• 2018

In recent times, gas insulated medium voltage (MV) circuit breakers (CB) form a vital component in power system network, considering its advantages such as reduced size and safety margins. Gas insulation characteristics of circuit breakers are generally measured by lightning impulse (LI) test according to IEC standard 60060-1 as a factory routine test. Considering the environmental issues of $SF_6$ gas, many research works are being carried out towards the mixture of $SF_6$ gases for high voltage insulation applications. However, few reports are only available regarding the LI withstand and streamer propagation characteristics (at both positive and negative polarity of waveform) of $SF_6/N_2$ gas mixture insulated medium voltage circuit breakers. In this paper, positive and negative polarity LI tests are carried out on 22 kV medium voltage circuit breaker filled with $SF_6/N_2$ gas mixture at different gas pressures (1-5 bar) and at different gas mixture ratios. Important LI parameters such as breakdown voltage, streamer velocity, time to breakdown and acceleration voltage are evaluated with IEC standard LI ($1.2/50{\mu}s$) waveform. Weibull distribution analysis of LI breakdown voltage data is carried out and 50% probability breakdown voltage, scale parameter and shape parameter are evaluated. Results illustrate that the $25%SF_6+75%N_2$ gas filled insulation considerably enhances the LI withstand and breakdown strength of MV circuit breakers. LI breakdown voltage of circuit breaker under negative polarity shows higher value when compared with positive polarity. Results show that maintaining the gas pressure at 0.3 MPa (3 bar) with 10% $SF_6$ gas mixed with 90% $N_2$ will give optimum lighting impulse withstand performance of 22 kV MV circuit breaker.

• Journal of the Optical Society of Korea
• /
• v.18 no.3
• /
• pp.207-216
• /
• 2014

In this work, we report detailed numerical analysis of the near-elliptic core index-guiding triangular-lattice and square-lattice photonic crystal fiber (PCFs); where we numerically characterize the birefringence, single mode, cut-off behavior and group velocity dispersion and effective area properties. By varying geometry and examining the modal field profile we find that for the same relative values of $d/{\Lambda}$, triangular-lattice PCFs show higher birefringence whereas the square-lattice PCFs show a wider range of single-mode operation. Square-lattice PCF was found to be endlessly single-mode for higher air-filling fraction ($d/{\Lambda}$). Dispersion comparison between the two structures reveal that we need smaller lengths of triangular-lattice PCF for dispersion compensation whereas PCFs with square-lattice with nearer relative dispersion slope (RDS) can better compensate the broadband dispersion. Square-lattice PCFs show zero dispersion wavelength (ZDW) red-shifted, making it preferable for mid-IR supercontinuum generation (SCG) with highly non-linear chalcogenide material. Square-lattice PCFs show higher dispersion slope that leads to compression of the broadband, thus accumulating more power in the pulse. On the other hand, triangular-lattice PCF with flat dispersion profile can generate broader SCG. Square-lattice PCF with low Group Velocity Dispersion (GVD) at the anomalous dispersion corresponds to higher dispersion length ($L_D$) and higher degree of solitonic interaction. The effective area of square-lattice PCF is always greater than its triangular-lattice counterpart making it better suited for high power applications. We have also performed a comparison of the dispersion properties of between the symmetric-core and asymmetric-core triangular-lattice PCF. While we need smaller length of symmetric-core PCF for dispersion compensation, broadband dispersion compensation can be performed with asymmetric-core PCF. Mid-Infrared (IR) SCG can be better performed with asymmetric core PCF with compressed and high power pulse, while wider range of SCG can be performed with symmetric core PCF. Thus, this study will be extremely useful for designing/realizing fiber towards a custom application around these characteristics.

• Journal of Industrial Convergence
• /
• v.20 no.11
• /
• pp.205-211
• /
• 2022

This study is a descriptive research study to identify the knowledge and compliance of multidrug-resistant organisms of nursing students with clinical practice. Data were collected from 212 nursing students in two nursing schools in D city from 1 November 2020 to 10 March 2021. The collected data were statistically analyzed using the SPSS/WIN 25.0 program. Correlations were found between knowledge and compliance of multidrug-resistant organisms (r=.40, p<.001). Therefore, to enhance the compliance of multidrug-resistant organisms of nursing students, it is necessary to prepare detailed theoretical and practical guidelines for multidrug-resistant organisms in the curriculum and clinical practice and to increase knowledge through multidrug-resistant organisms infection control education.

• Safety and Health at Work
• /
• v.14 no.1
• /
• pp.17-30
• /
• 2023

The human reproductive system can be affected by occupational exposure to many physical and chemical risk factors. This study was carried out to review the studies conducted on the issue of the pathophysiological effects of occupational physical and chemical risk factors on the reproductive system of females and males. In this systematic review, the databases such as "Google Scholar," "Pub-Med," "Scopus," and "Web of Science" were used. Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA 2020), the studies included in our study were published between 2000 and 2021. In order to extract the required data, all sections of the articles were reviewed. Out of 57 articles we reviewed, 34 articles were related to field studies and 23 articles to clinical studies. Among them, 43 studies dealt with the pathophysiological effects of chemical agents, six studies dealt with the pathophysiological effects of physical factors, and 8 studies dealt with the pathophysiological effects of physicochemical factors on the human reproductive system. Physical (noise, heat, and radiofrequency radiation) and chemical (such as carbamate and organophosphate pesticides, benzene, toluene, xylene, formaldehyde, NO2, CS2, manganese, lead, nickel, and n-hexane) risk factors had pathophysiological effects on the human reproductive system. The presence of these risk factors in the workplace caused damage to the human reproductive system. The rate of these negative pathophysiological effects can be reduced by performing appropriate managerial, technical, and engineering measures in work environments.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.1
• /
• pp.89-99
• /
• 2007

A Feeding trial was conducted to study the effects of three different sources and two levels of dietary gelatinized carbohydrate (GC) on nutrient utilization, growth, tissue composition and tissue enzyme activities of fingerlings of Catla catla (15.1-15.3 g). Six isocaloric (17.1-17.5 kJ/g) semi-purified diets were prepared either with rice, corn or tapioca at 40 or 50% GC each. The crude protein (CP) level used in the diet was 35% and 25% for 40% and 50% GC level, respectively to study the protein sparing effect of GC. The degree of gelatinization was higher for corn and tapioca than rice under similar cooking conditions. After a 60-d feeding trial, dry matter, carbohydrate, protein and lipid digestibility were higher in tapioca fed groups at both the levels of GC. However, the highest specific growth rate (SGR) and protein efficiency ratio (PER) were observed in the corn fed groups at 50% GC level indicating better utilization of nutrients from gelatinized corn. Feed conversion ratio (FCR) was almost similar in corn and tapioca fed groups between two levels of GC but in rice fed groups, FCR was lower in 40% GC than 50% GC level. The results indicated higher protein-sparing effect in corn and tapioca fed groups than rice fed groups. The order of gelatinized carbohydrate utilization in Catla catla fingerlings at 50% GC level was corn>tapioca>rice. At 40% GC level, corn and tapioca were comparable and more efficiently utilized than rice. In the corn fed groups, 50% GC was comparable with 40% GC level, whereas in rice and tapioca fed groups the 40% GC was better in terms of nutrient utilization. Liver glycogen content and hepatosomatic index were significantly (p<0.05) higher in those groups fed high GC (50%) irrespective of carbohydrate sources. Higher intestinal amylase and glucose-6-phosphate dehydrogenase activities were observed in higher GC fed groups than the lower GC groups. No mortality was found in any groups at any levels of GC.

• Fire Science and Engineering
• /
• v.31 no.1
• /
• pp.10-17
• /
• 2017

Securing fire safety using only fire-fighting facilities is difficult because causes of modern fire vary, such as architectural structures and building use patterns. In order for fire safety to be guaranteed by enacting and revising fire regulations reflecting the fire hazard characteristics and user's characteristics, the introduction of fire influence evaluation (fire risk assessment) system needs to be considered in a timely manner to be adopted but unfortunately two attempts before have failed. In this study, a fire case of urban lifestyle housing was surveyed to introduce a fire influence evaluation system and a field survey on the actual condition of the 414 urban lifestyle housing buildings and fire & evacuation simulation results of one representative building in Suyoung-gu and Nam-gu District of Busan Metropolitan City were analyzed. The necessity, procedures and implementation method of fire influence evaluation system were questioned and tested by the professional fire experts, fire officers and firefighters and architects. On the basis of these facts, introduction of (fire influence evaluation system) should be absolutely adopted and the fire department and fire regulation are eligible to implement the system. Therefore, fire regulation needs to be enacted or revised in accordance with the new fire environment and fire safety system that needs to be built up. Accordingly, aggressive promotion through public hearings on the necessity of fire impact assessments, consensus among departments and fostering experts to carry out fire influence evaluation system will be the core.

• Journal of the Korean Vacuum Society
• /
• v.16 no.6
• /
• pp.446-452
• /
• 2007

[ $(Pb_{1.1},La_{0.08})(Zr_{0.65}.Ti_{0.35})O_3$ ] thin films on the $Pt/Ti/SiO_2/Si$, $TiO_2(interlayer)/Pt/Ti/SiO_2/Si$ substrate were fabricated by the R.F. magnetron-sputtering method and considered their characteristics depending on $TiO_2$ interlayer. Changing the deposition conditions of $TiO_2$ interlayer, we obtained $TiO_2$ anatase single phase and rutile single phase. PLZT was deposited on these substrates and analyzed by x-ray diffraction(XRD) for there crystallinity and orientation. To investigate $PLZT-TiO_2$, $TiO_2-Pt$ interface, glow discharge spectrometer(GDS) analysis was carried out and we performed electrical measurements for dielectric properties of PLZT thin films. The PLZT thin film on $TiO_2$ anatase interlayer was found to have (110)-preferred orientation and 12.6 ${\mu}C/cm^2$ remaining polarization value.

• Asian-Australasian Journal of Animal Sciences
• /
• v.3 no.3
• /
• pp.161-164
• /
• 1990

Ninety six Rambouillet ${\times}$ Kaghani intact male lambs of 18 months of age were divided into 6 groups of 16 lambs each, groups being G-1, G-2, G-3, G-4, G-5 and G-6. Average liveweight of animals on different treatments at day 0 of the experiment was G-1 (24.68 S.D 3.35), G-2 (24.56 S.D 2.55), G-3 (24.53 S.D 2.90), G-4 (24.51 S.D 3.38), G-5 (24.58 S.D 3.58) and G-6 (24.81 S.D 3.43). Animals on treatment G-1 were fed only maize silage ad libitum, G-2 had been offered maize silage ad libitum plus 4.8 kg of commercial concentrate (Sona Vanda) per group, G-3 maize silage ad libitum plus 4.8 kg of crushed maize grain per group. G-4 lambs were fed oat silage ad libitum plus 4.8 kg of crushed maize per group, G-5 oat silage plus 4.8 kg of commercial concentrate per group and G-6 only oat silage ad libitum. The results showed highly significant differences (p<0.01) among treatment groups in silage intake throughout the feeding trial. G-2 group showed the highest silage intake while treatment G-4 showed the lowest silage intake for the first two months and treatment G-6 for the last two months. The results of growth rates (g/d/animal) showed that treatments G-1 and G-6, where no supplementation was given, had a weight loss throughout the feeding trial. However, weight loss in treatment G-6 was more severe than treatment G-1. Treatments G-2, G-3, G-4 and G-5 all showed weight gain however, treatment G-2 had the most gain. G-2 group also showed the highest wool production while G-6 the lowest. These results indicated that silage when made from full bloom crops of oats and silage fed alone without any supplementation causes weight loss in sheep. Supplementation with concentrates having 19% CP is far better than the crushed maize grain and maize silage is better than oats silage. Maize silage is superior than oat silage however, better performance could be expected if silages were made at the early bloom (dough) stage of plant maturity. The results indicate that treatment G-2 shows highest response while treatment G-6 the lowest. So the response of different treatments on both the parameters of weight gain and wool production is almost similar.

• Journal of the Korean Vacuum Society
• /
• v.17 no.1
• /
• pp.28-33
• /
• 2008

Lanthanum modified lead zirconate titanate ($Pb_{1.1}La_{0.08}Zr_{0.65}Ti_{0.35}O_3$) thin films were fabricated on indium doped tin oxide (ITO)-coated glass substrate by R.F magnetron sputtering method. The thin films were deposited at $500^{\circ}C$ and post-annealed with various temperature ($550-750^{\circ}C$) by rapid thermal annealing technique. The structure and morphology of the films were characterized with X-ray diffraction (XRD) and atomic force microscopy (AFM) respectively. The hysteresis loops and fatigue properties of thin films were measured by precision material analyzer. As the annealing temperature was increased, the remnant polarization value was increased from $10.6{\mu}C/cm^2$ to $31.4{\mu}C/cm^2$, and coercive field was reduced from 79.9 kV/cm to 60.9 kV/cm. As a result of polarization endurance analysis, the remnant polarization of PLZT thin films annealed at $700^{\circ}C$ was decreased 15% after $10^9$ switching cycles using 1MHz square wave form at ${\pm}5V$.