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        검색결과 452

        21.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구는 강직성 척추염 환자를 대상으로 12주간의 가정기반운동(home-based exercise) 프로그램을 수행하여 환자 특성별 염증관련 혈액지표, 관절가동범위, 통증척도 및 심리적인 지표 세부적이고 종합적으로 제공하고자 수행되었다. 연구의 목적을 위해 강직성 척추염을 진단받은 환자 10명을 선정하여 연령별(30대 vs. 40대 vs. 50대), 성별(남성 vs. 여성) 및 유병기간(5년 미만 vs. 5년 이상)으로 구분하였다. 가정기반 운동 프로그램은 유산소운동과 필라테스 기반 저항성 운동의 복합운동 형태로 최대심박수 (maximal heart rate, MHR)의 50-70% 강도에서 주 4회, 12주 동안 수행되었다. 연구결과, 12주간의 가 정기반운동 중재 후 강직성 척추염 환자의 혈중 CRP (C-reactive protein) 농도가 감소됨으로써 (-35.6%, p=.017) 혈중 염증 수치가 개선되었으며, 각 관절(고관절, 허리, 경추)의 가동성이 향상되었다(p<.05). 또한 질병활성도(Bath ankylosing spondylitis disease activity index, BASDAI)는 -67%(p=.005), 시각통증지표 (Visual analogue scale, VAS)는 -64.8%(p=.005) 감소됨으로써 강직 및 통증이 전반적으로 완화되었다. 특히, 우울 정도가 -65.5%(p=.005), 불안 정도는 -55.2%(p=.008) 감소됨으로써 12주간의 가정기반운동은 신체적 변화 뿐 아니라 심리적인 요인도 개선 시켜주는 것으로 나타났다. 반면, 강직성 척추염 환자의 연령, 성별, 유병기간에 따른 운동 효과 차이는 나타나지 않았다(p>.05). 따라서 이 연구에서 적용된 12주 간의 가정기반운동이 환자 특성과 상관없이 강직성 척추염 환자에게 보편적으로 사용될 수 있는 효과적인 운동프로그램이 될 수 있을 것으로 사료된다.
        4,800원
        22.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 어머니의 코칭역량과 양육불안의 일반적 경향에 따라 어떠한 차이가 있는지를 살펴보고 어머니의 코칭역량과 양육불안이 유아의 자아존중감에 어떠한 영향을 미치는지에 대해 알아보고자 하였다. 연구대상은 만3∼5세 유아기 자녀를 둔 어머니 259명을 대상으로 설문조사를 하였고 수집된 자료는 SPSS 21.0 을 사용하여 빈도, 백분율, Pearson 상관관계분석, 다중회귀분석을 실시하였다. 본 연구결과는 다음과 같다. 첫째, 어머니의 코칭역량과 양육불안, 유아의 자아존중감의 일반적 경향을 알아본 결과, 코칭역량은 전체 평균점수가 보통보다 높은 것으로 나타났으며 양육불안은 낮은 것으로 나타났다. 또한 유아의 자아존중감은 전체 평균은 보통이상으로 나타났다. 둘째, 어머니의 코칭역량 및 양육불안의 하위요인들과 유아의 자아존중감의 하위요인들 모두 유의미한 상관이 있음을 알 수 있었다. 셋째, 어머니의 코칭역량 중 ‘사회적 역량요인’과 양육 불안 중 ‘부모역할 효능감으로 인한 불안’과 ‘자녀에 대한 염려요인’이 유아의 자아존중감에 상대적으로 영향력이 있는 것으로 나타났다. 즉 어머니의 코칭역량이 높을수록 그리고 양육불안이 낮을수록 유아의 자아존중감에 긍정적 영향을 미치는 것으로 나타났다. 본 연구는 이러한 결과를 바탕으로 어머니의 코칭역량을 키우고 양육불안을 낮추기 위한 부모교육 및 프로그램 개발을 위한 기초자료를 제공하는 데 의의가 있다.
        5,400원
        23.
        2021.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The conversion of all carbon preforms to dense SiC by liquid infiltration can become a low-cost and reliable method to form SiC-Si composites of complex shape and high density. Reactive sintered silicon carbide (RBSC) is prepared by covering Si powder on top of 0.5-5.0 wt% Y2O3-added carbon preforms at 1,450 and 1,500°C for 2 hours; samples are analyzed to determine densification. Reactive sintering from the Y2O3-free carbon preform causes Si to be pushed to one side and cracking defects occur. However, when prepared from the Y2O3-added carbon preform, an SiC-Si composite in which Si is homogeneously distributed in the SiC matrix without cracking can be produced. Using the Si + C = SiC reaction, 3C and 6H of SiC, crystalline Si, and Y2O3 phases are detected by XRD analysis without the appearance of graphite. As the content of Y2O3 in the carbon preform increases, the prepared RBSC accelerates the SiC conversion reaction, increasing the density and decreasing the pores, resulting in densification. The dense RBSC obtained by reaction sintering at 1,500 oC for 2 hours from a carbon preform with 2.0 wt% Y2O3 added has 0.20% apparent porosity and 96.9% relative density.
        4,200원
        24.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The emission of particulate matter and volatile organic compounds (VOCs) from a motor vehicle painting booth was quantitatively evaluated. Most particulate matter was emitted during the spraying process, in which the PM10 concentration was 16.5 times higher than that of the drying process. When the paint was being sprayed, the particles with a diameter of 1.0~2.5 μm accounted for 39.4% and particles greater than 2.5 μm in diameter accounted for 30.6% of total particles. On the other hand, small particles less than 0.5 μm in diameter accounted for 52.4% of total particles during the drying process. In contrast to the particulate matter, high concentrations of VOCs were emitted during both spraying and drying processes. Butyl acetate, xylene, toluene, and m-ethyltoluene were the most abundant VOCs emitted from the motor vehicle painting booth. Additionally, xylene, butyl acetate, toluene, and 1,2,3-trimethylbenzene were the dominant ozone precursors. Especially, xylene exhibited the highest ozone production contribution (32.5~44.4%) among 34 species of the ozone precursors. The information obtained in this study can be used to establish a suitable management strategy for air pollutants from motor vehicle painting booths.
        4,200원
        25.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The conversion of carbon preforms to dense SiC by liquid infiltration is a prospectively low-cost and reliable method of forming SiC-Si composites with complex shapes and high densities. Si powder was coated on top of a 2.0wt .% Y2O3-added carbon preform, and reaction bonded silicon carbide (RBSC) was prepared by infiltrating molten Si at 1,450oC for 1-8 h. Reactive sintering of the Y2O3-free carbon preform caused Si to be pushed to one side, thereby forming cracking defects. However, when prepared from the Y2O3-added carbon preform, a SiC-Si composite in which Si is homogeneously distributed in the SiC matrix without cracking can be produced. Using the Si + C → SiC reaction at 1,450oC, 3C and 6H SiC phases, crystalline Si, and Y2O3 were generated based on XRD analysis, without the appearance of graphite. The RBSC prepared from the Y2O3-added carbon preform was densified by increasing the density and decreasing the porosity as the holding time increased at 1,450oC. Dense RBSC, which was reaction sintered at 1,450oC for 4 h from the 2.0wt.% Y2O3-added carbon preform, had an apparent porosity of 0.11% and a relative density of 96.8%.
        4,000원
        26.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Deep learning models, which imitate the function of human brain, have drawn attention from many engineering fields (mechanical, agricultural, and computer engineering etc). The major advantages of deep learning in engineering fields can be summarized by objects detection, classification, and time-series prediction. As well, it has been applied into environmental science and engineering fields. Here, we compiled our previous attempts to apply deep learning models in water-environment field and presented the future opportunities.
        4,500원
        27.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the substitution effect of phosphate and isolated soybean powder (ISP) by Allomyrina dichotoma larvae powder (AP) in emulsion sausage. The sausages were prepared for five treatments: 1) positive control (PC): sausages manufactured with sodium pyrophosphate (0.3%) and ISP (1%); 2) negative control (NC): sausages manufactured without sodium pyrophosphate, and ISP; 3) phosphate replacement (PR): sausages manufactured with ISP and AP (1%); 4) ISP replacement (IR): sausages manufactured with sodium pyrophosphate and AP; 5) phosphate and ISP replacement (PIR): sausages manufactured with AP. The 1% AP extract showed DPPH radical scavenging (45.65±2.468%) and metal chelating (22.46±3.559%) activity. The high pH value of AP (8.03) increased the pH of the meat batter of PR, IR, and PIR (p<0.05), but there was no inhibitory effect on cooking loss. Cooking loss of IR was not significantly different with PC due to phosphate. The addition of AP decreased the L* and a* values and increased the b* values, and decreased hardness, chewiness, and springiness of PR, IR, and PIR (p<0.05). AP did not inhibit lipid oxidation in sausages, in contrast to phosphate. In sensory evaluation, the addition of AP resulted in low scores for all sensory parameters of the sausages, although most panels had normal or positive awareness (p<0.05). Aroma was more influential on samples than color. Overall, AP did not replace phosphate and ISP in the sausages. Therefore, processes such as eliminating unique aroma and color and increasing solubility through particle size control are necessary to use AP as a protein source.
        4,200원
        31.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        n-Nonane, 1¸2¸4-trimethylbenzene (124-TMB), toluene, total xylene (TXYL), isopropyl alcohol (IPA), and methyl ethyl alcohol (MEK) are major volatile organic compounds (VOCs) emitted from printing industries. The absorption amount of a single VOC per unit weight of silicone oil was as follows in the order of 189.5 g/kg-silicone oil for n-nonane, 91.7 g/kg-silicone oil for 124-TMB, and 60.1 g/kg-silicone oil for TXYL. Although hydrophobic VOCs were more absorbed in silicone oil than hydrophilic VOCs such as IPA and MEK, IPA and MEK, which had log Kow values of 1 or less, also were absorbed more than 26.0 g/kg-silicone oil. In two and three mixed VOCs of n-nonane, 124-TMB, and toluene, the absorption amount of each in silicon oil was less than that of single a VOC. The total absorption amount of two mixed VOCs ranged from 47.9 g to 138.7 g/kg-silicone oil, and the total absorption amount of three mixed VOCs was 65.8 g/kg-silicone oil. These results suggest that silicone oil is a promising pretreatment solution capable of absorbing high concentrations of VOCs that are intermittently emitted from printing industries. The absorption information of VOCs obtained in this study can be used as the design parameters of a damping device for the pretreatment of VOCs.
        4,000원
        32.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Toxicities to many organs caused by humidifier disinfectants have been reported. Recently, humidifier disinfectants have been reported to cause cardiovascular, embryonic, and hepatic toxicities. This study was designed to investigate the toxic mechanism of humidifier disinfectants and compare toxicity in a cellular model and a zebrafish animal model. Because brain toxicity and skin toxicity have been less studied than other organs, we evaluated toxicity in a human dermal cell line and zebrafish under various concentrations of humidifier disinfectants that included polyhexamethyleneguanidine phosphate (PHMG), oligo-[2-(2-ethoxy)-ethoxyethylguanidinium- chloride] (PGH) and methylchloroisothiazolinone/methylisothiazolinone (CMIT/MIT). A human dermal fibroblast cell line was treated with disinfectants (0, 2, 4, 6, 8, and 16 mg L-1) to compare their cytotoxicity. The fewest PHMG-treated cells survived (up to 33%), while 49% and 40% of the PGH- and CMIT/MIT-treated cells, respectively, survived. The quantification of oxidized species in the media revealed that the PHMGtreated cells had the highest MDA content of around 28 nM, while the PGH- and CMIT/ MIT-treated cells had 13 and 21 nM MDA, respectively. As for brain toxicity, treatment of the zebrafish tank water with CMIT/MIT (final 40 mg L-1) for 30 min resulted in a 17- fold higher production of reactive oxygen species (ROS) than in the control. Treatment with PGH or PHMG (final 40 mg L-1) resulted in 15- and 11-fold higher production, respectively. The humidifier disinfectants (PHMG, PGH, and CMIT/MIT) showed severe dermal cell toxicity and brain toxicity. These toxicities may be relevant factors in understanding why some children have language disorders, motor delays, and developmental delays from exposure to humidifier disinfectants.
        4,000원
        33.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 유아교사의 인권의식, 전문성인식, 삶의 만족도가 다문화교 수효능감에 미치는 영향을 알아보는 것이다. 본 연구를 위해서 예비조사및 본조사를 구분하여 진행하였고, 본 조사는 2019년 7월 10일부터 8월 20일까지 전라남도 지역에 위치한 유아교사 141명을 대상으로 설문조사를 실시하였다. 수집 된 자료는 설문 문항에 대한 신뢰도를 검증하기 위하여 Cronbach α 계수와 유아교사의 인권의식, 전문성인식, 삶의 만족도, 다문화교수효능감 간의 관계를 살 펴보기 위하여 Pearson 적률상관분석 및 유아교사의 인권의식, 전문성인식, 삶의 만족도가 다문화교수효능감에 미치는 영향을 알아보기 위하여 중다회귀분석을 실시하였다. 연구결과로는 첫째, 다문화교수효능감과 삶의 만족도, 전문성인식 간에 유의미한 정적 상관관계가 있는 것으로 나타났다. 둘째, 다문화교수효 능감에 영향을 미치는 변수로는 교사의 전문성인식이 유의미한 정적 예측변인으로 나타났다. 이에, 본 연구결과는 다문화정책 지원을 위한 교사교육 프로그 램개발에 의미있는 기초자료를 제공해 줄 것으로 판단한다.
        5,200원
        34.
        2020.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ZnO thin films are of considerable interest because they can be customized by various coating technologies to have high electrical conductivity and high visible light transmittance. Therefore, ZnO thin films can be applied to various optoelectronic device applications such as transparent conducting thin films, solar cells and displays. In this study, ZnO rod and thin films are fabricated using aqueous chemical bath deposition (CBD), which is a low-cost method at low temperatures, and environmentally friendly. To investigate the structural, electrical and optical properties of ZnO for the presence of citrate ion, which can significantly affect crystal form of ZnO, various amounts of the citrate ion are added to the aqueous CBD ZnO reaction bath. As a result, ZnO crystals show a nanorod form without citrate, but a continuous thin film when citrate is above a certain concentration. In addition, as the citrate concentration increases, the electrical conductivity of the ZnO thin films increases, and is almost unchanged above a certain citrate concentration. Cu(In,Ga)Se2 (CIGS) solar cell substrates are used to evaluate whether aqueous CBD ZnO thin films can be applicable to real devices. The performance of aqueous CBD ZnO thin films shows performance similar to that of a sputter-deposited ZnO:Al thin film as top transparent electrodes of CIGS solar cells.
        4,000원
        35.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 생물 다양성의 지표종인 개미류의 시기별 우점종 및 개체군 변동을 살펴보고, 추후 기후변화에 따른 개체군 변화의 기초자료를 확보하고자 수행되었다. 조사 기간은 2013년 6월부터 9월까지 고도별 조사 지점을 선정하고, 함정트랩을 사용하여 정방형조사법(10m×10m)으로 개미의 분포를 조사하였다. 고도별 조사 결과, 총 3아과 11속 14종 15,466개체가 채집되었다. 낮은 고도(700m)에서 13종 4,548개체의 분포가 확인되었으며, 우점종은 일본장다리개미(49.9%)로 나타났고, 중간 고도(900m)에서 8종 9,129개체가 채집되었으며, 우점종으로 극동혹개미(57.7%)의 분포가 확인되었으며, 높은 고도 (1,100m)에서 10종 1,789개체가 확인되었으며, 우점종으로 코토쿠뿔개미(43.3%)가 확인되었다. 고도별로 일본장다리개미, 스미스개미, 극동혹개미는 폭넓게 분포하는 것으로 확인되었다.
        4,000원
        36.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내에 유통되는 식품용 기구 및 용기·포장 중 4종류(유리제, 도자기제, 법랑 및 옹기류)의 재질, 총 198건을 수거하여 식품으로 이행 가능성이 있는 중금속(납, 카드뮴, 비소 및 안티몬)에 대하여 이행량을 ICP-MS 로 조사하였다. 식품유사용매는 4% 초산을 사용하여 25oC를 유지하면서 24시간 방치한 액을 시험용액으로 하였으며, 시험법 검증을 위하여 검량선, 검출한계, 정량한계, 회수율, 정밀성 및 측정불확도를 산출하였다. 이행량 조사 결과 유리제의 경우 납과 카드뮴은 각각 N.D.-752.21 μg/L, N.D.- 1.99 μg/L 이고, 도자기제는 납, 카드뮴 및 비소가 각각 N.D.-1,955.86 μg/L, N.D.-74.06 μg/L, N.D.-302.40 μg/L 이며, 법랑의 납, 카드뮴 및 안티몬은 각각 N.D.-4.48 μg/L, N.D.- 7.00 μg/L, N.D.-52.00 μg/L 이였다. 그리고 옹기류의 납, 카드뮴 및 비소는 각각 N.D.-13.68 μg/L, N.D.-0.04 μg/L, N.D.-6.71 μg/L 수준으로 확인 되었다. 이와 같은 결과를 근거로 유리제 등으로부터 식품으로 이행 가능한 중금속의 위해도는 총 섭취량대비 4.83% 이하로 비교적 안전한 것으로 판단된다. 또한, 본 연구결과는 국내에서 유통중인 유리제 등의 식품용 기구 및 용기·포장은 모두 국내의 기준·규격에 적합함을 확인하였다.
        4,000원
        37.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sulfide dissolved in wastewater is a potential source of hydrogen sulfide. Hydrogen sulfide is an odorous substance that causes civil complaints and is a dangerous substance that threatens the corrosion of structures and the safety and health of workers. The removal efficiencies of the chemical oxidant and the coagulants were compared to evaluate the removal of dissolved sulfide. Since the effectiveness may vary depending on the characteristics of the wastewater, water was used as a control, and 5 mg/L of dissolved sulfide was dissolved in water and sewage wastewater. When oxidant was used, the results showed a high sulfide removal rate in sewage wastewater than water, and the removal efficiency was enhanced with increasing oxidant concentration. Sulfide removal efficiencies after one hour after injecting oxidants H2O2, NaOCl, NaClO2 to sewage wastewater were 70%, 90%, and 100%, respectively. After the oxidants were administered four times, the removal was 90%, 100%, and 100%, respectively. In the case of sulfide removal with the oxidizing agent, the removal efficiency was NaClO2, NaOCl, H2O2 (highest - lowest). NaClO2 showed 100% removal efficiency within 10 minutes under all conditions (A condition, B condition), making it the most sewage effective agent in this study. In the case of the coagulants, 100% of the sulfides dissolved in water were removed in the first 10 minutes under all conditions. In sewage wastewater, FeCl2 and FeSO4 also showed 100% removal efficiency under all conditions after one hour, and FeCl3 showed 90% and 99% removal rates under A and B conditions, respectively. That is, the monovalent iron coagulants (FeCl2, FeSO4) were found to be somewhat more effective in the removal of sulfides in sewage wastewater than the divalent iron (FeCl3) coagulants. When the sulfides were removed with coagulants, FeCl2 had the highest removal efficiency followed by FeSO4 and FeCl3. Moreover, it was found that NaClO2 has the best reaction efficiency at the minimum reaction time and the reaction concentration.
        4,000원
        39.
        2019.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Homogeneous multicomponent indium gallium zinc oxide (IGZO) ceramics for transparent electrode targets are prepared from the oxides and nitrates as the source materials, and their properties are characterized. The selected compositions were In2O3:Ga2O3:ZnO = 1:1:2, 1:1:6, and 1:1:12 in mole ratio based on oxide. As revealed by X-ray diffraction analysis, calcination of the selected oxide or nitrides at 1200oC results in the formation of InGaZnO4, InGaZn3O6, and InGaZn5O8 phases. The 1:1:2, 1:1:6, and 1:1:12 oxide samples pressed in the form of discs exhibit relative densities of 96.9, 93.2, and 84.1%, respectively, after sintering at 1450oC for 12 h. The InGaZn3O6 ceramics prepared from the oxide or nitrate batches comprise large grains and exhibit homogeneous elemental distribution. Under optimized conditions, IGZO multicomponent ceramics with controlled phases, high densities, and homogeneous microstructures (grain and elemental distribution) are obtained.
        4,000원
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