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        검색결과 53

        2.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The paint removal of fighter jets is just as important as the painting, because perfect paint removal ensures the quality of the exterior painting on the aircraft. However, the current conditions for paint removal work of the ROKAF’s are poor. It is identified that the painting process currently implemented by the ROKAF is not only exposed to harmful compounds such as harmful dust and hexavalent chromium, but also consumes a lot of water. Thus, the introduction of advanced facility is considered. This study compares the fighter jets painting removal process currently applied by the Korean Air Force with the improved laser coating removal process of the US Air Force, and conducts an incremental analysis to perform economic analysis for the introduction of advanced facility. Four scenarios were envisioned on the premise of an increase in the number of fighters in the future, incremental analysis shows that laser coating removal method is advantageous in all scenarios. In addition, it is recommended that paint removal cycle keeps the current 12-year and the outsourcing amount to civilian depot is reduced.
        4,500원
        4.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Korean Air-Force aircraft maintenance depot paints the exterior of various aircraft, including high-tech fighters. Aircraft exterior painting is a maintenance process for long-term life management by preventing damage to the aircraft surface due to corrosion. The de-painting process is essential to ensure the quality of aircraft exterior paints. However, because the Korean Air-Force’s de-painting process is currently done with sanding or Plastic Media Blasting (PMB) method, it is exposed to harmful dust and harmful compounds and consumes a lot of manpower. This study compares the de-painting process currently applied by the ROK Air-Force and the more improved process of the US Air Force, and performs economic analysis for the introduction of advanced equipment. It aims to provide information that can determine the optimal time to introduce new facilities through Cost-Volume-Profit (CVP) analysis. As a result of the analysis, it was confirmed that the sanding method had the most economical efficiency up to 2 units per year, the PMB method from 3 to 21 units, and the laser method from 22 units or more. In addition, in a situation where the amount of de-painting work is expected to increase significantly due to the increase in fighters in future, BEP analysis was conducted on the expansion of the existing PMB method and the introduction of a new laser method. As a result of the analysis, it was confirmed that it is more economical to introduce the laser method when the amount of work exceeds the PMB work capacity(18 units per year). The paper would helpful to improve the productivity and quality of the Korean Air Force Aircraft maintenance depot through timely changes of facilities in the workplace in preparation for expansion.
        4,200원
        10.
        2019.04 구독 인증기관·개인회원 무료
        본 조사지인 돌리네 습지보호지역은 경북 문경시 산북면 굴봉산 정상부에 위치하였으며, 물이 고이기 힘든 돌리네(doline) 지형에 형성된 희귀 습지이다. 뿐만 아니라 멸종위기종과 법적보호종이 분포하는 등 생물다양성 또한 매우 풍부한 것으로 평가되고 있다. 그러나 습지보호지역 주변으로 과수원 등 경작지가 형성되어 있어, 관리 및 보전을 위한 조사 및 대책이 필요하다. 따라서 본 조사에서는 습지보호지역의 체계적인 관리를 위하여 돌리네 습지의 곤충상을 조사하였다. 조사 방법에는 곤충의 다양한 습성과 서식환경을 고려하여, Searching, Sweeping, Pitfall trap, Bucket trap으로 총 4가지의 채집방법으로 조사를 실시하였다. 그 결과 총 11목 82과 188속 237종이 확인되었으며, 이중 딱정벌레목이 가장 많이 출현하였다. 특이사항으로 환경부지정종 51종(중복포함)이 조사되었으며, 그중 멸종위 기종 1종이 확인되었다. 본 연구를 통해 돌리네 습지보호지역의 곤충상을 파악하고 관리 및 보전에 대한 기초자료를 제공하고자 한다.
        11.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to measure empathy in physical therapy students using a self-report measure of empathy. One hundred seventy students from three different majors participated in the study. The physical therapy group consisted of 49 people, 24 men and 25 women. The psychotherapy group has 59 people, 17 males and 42 females. 62 participants were randomly assigned to the engineering group, with 18 males and 44 females. It was hypothesized that empathy would be higher in physical therapy students compared to those in engineering. Empathy Quotient (EQ) supported the research hypothesis, with students in physical theapy higher than students in engineering There is no statistically significant difference in the EQ between physical therapy and psychotherapy. There were also differences in empathy according to major and gender. Our research suggests that empathy needs to be promoted through education and training.
        4,000원
        13.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the current study, a total of 102 common Todarodes pacificus squid caught in the East Sea were investigated for parasitological research. The results revealed that 33 (32.35%) out of 102 squid were infected by Nybelinia surmenicola, the mean intensity was 5.58 parasites per squid, and the maximum abundance was 11. Morphological analysis using a field emission scanning electron microscope showed the characteristic features of N. surmenicola. Molecular identification based on the 28S rRNA gene confirmed the isolated parasite as N. surmenicola, while phylogenetic analysis revealed that N. surmenicola isolated in this study was clustered with N. surmenicola isolated from Japan. This is the first report of phylogenetic characterization of N. surmenicola isolated from Korea.
        4,000원
        14.
        2017.11 구독 인증기관·개인회원 무료
        Ohmic heating is one of advanced thermal processing techniques which utilize conversion of electrical energy into heat. In our study, a feasibility of ohmic heating was tested to cook instant rice cake to improve energy efficacy as an alternative heating methods of conventional electrical kettle. Ohmic heating was conducted using customized ohmic cell (7.5×4.5×9.5 cm) equipped with titanium electrodes. Instant rice cakes in soup were ohmically heated up to 100°C at different electric fields (9, 12, 15 & 18 V/cm) and temperature holding times (60, 80, 100 & 120 s). Thermocouple was placed into both soup and rice cake to evaluate the temperature profile and energy efficacy. Temperature, voltage and current across the sample were measured and recorded at every 3 s using data acquisition system (DAQ). Mathematical model was developed to calculate the internal energy generation rate (QR, W). Internal energy generation rate (QR, W) was integrated versus temperature come-up time (s) to compute the total internal energy dose (ET, J) using MATLBA software. For energy efficacy (Eff), it was calculated ratio of total internal energy dose (ET, J) to heat quantity (Qh, J). During ohmic heating, temperature come-up time was significantly reduced as a function of elevated electric field (P<0.05). For example, 9V/cm of electric field showed 6.2±0.4 min of temperature come-up time up to 100°C. Higher electric field at 18 V/cm reduced temperature come-up time to 1.9±0.1 min. The electric field of 15 V/cm showed the best energy efficacy as 0.78 which meant 78% of electrical energy was converted into thermal energy for heating. In the texture profile analysis, the most preferable harness was found as 6.191 N at 15 V/cm and 100 s holding time. Our study showed the potential of ohmic heating to cook instant rice cakes for home meal replacement (HMR) and outdoor foods.
        15.
        2017.10 구독 인증기관·개인회원 무료
        This study was conducted to in vitro antioxidant and anti-inflammatory activities of EtOH extracts of Cordyceps militaris (CM). Antioxidant potential, total phenolic and flavonoid contents of CM EtOH extracts were determined by Folin-Ciocalteu method and the aluminum chloride colorimetric method, respectively. Antioxidant activity of CM extracts was measured by following some well-established methods for free radical scavenging such as 2,2-diphenyl-picrylhydrazyl hydrate and 1,2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid). Moreover, Anti-inflammatory activity of CM extracts was determined by measuring the inhibition of nitric oxide (NO) production in lipopolysaccharide/interferon-γ-activated RAW264.7 macrophage-like cells. In addition, cytotoxicity of CM extracts against macrophages was determined by MTT assay. Our results showed that total phenolic content was 19.7 mg gallic acid/g extract. Total flavonoid content was 5.0 mg Naringin/g. Its antioxidant activity was assessed by IC50 value and the values are 338.8 μg/ml (DPPH radical scavenging), 35.4 μg/ml (ABTS radical scavenging). In addition, CM extracts attenuated NO production through the reduction of cellular inducible NO synthase protein expressions. Using MTT assay on indicate that CM extracts showed no toxicity. In conclusion, these results provide important evidence that CM extracts can potentially be used to antioxidant and anti-inflammatory agent.
        16.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The squid Todarodes pacificus is a commercially important fishery species in East Asia. As East Asians consume raw or lightly cooked squids, there has been growing concern about parasitic infections associated with squid consumption. In the current study, five squids caught in the East Sea were sampled for parasitological research from the biggest fishery market in Seoul, Republic of Korea. They were dissected and examined for parasites using a light microscope. Proteocephalus sp. was isolated and identified using field emission scanning electron microscopy, PCR, and sequencing. Given that Proteocephalus spp. can be affected by water temperature and geographical characteristics, further research on Proteocephalus spp. with respect to changes in water temperature in the East Sea is important.
        3,000원
        17.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        미꾸라지에서의 Nitrofuran계 대사물질인3-amino-2-oxazolidone (AOZ), 5-morpholinomethyl-3-amino-2-oxazolidinone (AMOZ), 1-ammino-hydantoin (AHD)와 semicarbazide (SEM)의 잔류량을 검사하기 위해HPLC-MS/MS를 이용한 신속한 정량법이 개발되었다. 2-nitrobenzaldehyde (2-NBA)를 이용해 50℃에서 1시간 동안 산 가수분해와 유도체화 과정을 거친 뒤에, 액-액 분배로 정제와 추출을 하였다. 회수율은 음성시료에 3가지 농도 0.5, 1.0, 2.0 μg/kg의 표준액을 첨가하여 평가하였고 평균 회수율은 75.1-108.1% 이었다. 정밀성(%RSD)은 일내 8.7% 이하, 일간 8.5% 이하였다. 직선성은 NBAOZ는 0.2-20 μg/Kg, NBAMOZ는 0.8-20 μg/Kg, NBAHD는 0.2-20 μg/Kg, NBSEM 는 0.1-20 μg/Kg 범위에서 모두 상관계수 0.99이상이었다. 검출한계(LOD)는 NBAOZ 0.06 μg/Kg, NBAMOZ 0.24 μg/Kg, NBAHD 0.06 μg/Kg, NBSEM 0.03 μg/Kg이었고, 정량한계(LOQ)는 NBAOZ 0.2 μg/Kg, NBAMOZ 0.8 μg/Kg, NBAHD 0.2 μg/Kg, NBSEM 0.1 μg/Kg 이었다. 가수분해 및 유도체화 소요시간을 1시간으로 줄여 만든 신속 간편한 이 시험법이미꾸라지 중 nitrofuran metabolites잔류량 분석에 적합함을 확인할 수 있었다.
        4,000원
        19.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The sexual maturation occurred by the changes of steroid hormones was known to sex-dependently and/or agedependently regulate the lipid metabolism in various animal species. Our current study demonstrates that lipid and its functional fatty acids can be changed depending on the status of sexual maturation. Of the functional fatty acids, γ- linolenic acid (GLA; 18:3n-6) is an important factor for maintaining human health. The purpose of our study was to investigate the level of GLA in mice with different stages of sexual maturation. To this end, the longissimus muscle (LM) of immature (3-week-old) and mature (7-week-old) female mice was analysed for the fatty acid composition by gas chromatography. Furthermore, both gene and protein level of Δ6 desaturase (FADS2) which is involved in GLA metabolism by real time PCR and Western blotting, respectively. Mature females showed greater (P<0.05) serum 17β -estradiol (E2) level and LM GLA contents than immature group. The mRNA and protein levels of FADS2, which converts precursor linoleic acid into GLA, were higher (P<0.05) in mature female mice than in immature mice. In conclusion, these results show that sexual maturation of female mice induces GLA and FADS2 contents in LM.
        4,000원
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