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        검색결과 53

        1.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내에서 처음으로 도입한 기상 항공기에 탑재한 G-band 수증기 라디오미터(GVR) 관측으로 산출된 가강수량의 품질 관리 방법을 제안하였다. GVR 빔의 연직 최단 경로 자료만 사용하기 위해 기상 항공기의 자세 정보(pitch와 roll 각도)를 활용하였고, GVR 가강수량이 20 mm 이상의 자료를 제거하는 방법을 품질 관리에 적용하였다. GVR 가강수량 이 20 mm 이상으로 증가할 때, 웜로드(Warm load) 평균 전력과 스카이로드(Sky load) 평균 전력의 차이가 0에 가까이 수렴하는 특성을 확인하였고, 이는 COMS (Communication, Ocean and Meteorological Satellite)의 운형, 운정고도, 운 량자료와 구름통합관측기기(CCP), 강수입자 측정기(PIP)로 측정된 강수 및 구름 입자 크기로 확인한 하층운과 중층운에의한 높은 밝기온도 때문으로 판단된다. 구름 많은 날의 품질 관리 적용 전후의 GVR 가강수량을 LDAPS (Local Data Assimilation and Prediction System) 가강수량과 정량적으로 비교하였는데 RMSD (Root Mean Square Difference)는 2.9 mm에서 1.8 mm로 감소하였고, KLAPS (Korea Local Analysis and Prediction System)와의 RMSD는 5.4 mm에서 4.3 mm로 감소하여 향상된 정확도를 보였다. 또한 품질 관리를 적용한 GVR 가강수량과 드롭존데 가강수량 관측 자료 을 활용하여 COMS 가강수량과도 정량적으로 비교평가함으로써 본 연구에서 제안한 GVR 가강수량의 품질 관리 방법 의 유효성을 확인하였다.
        4,600원
        3.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study presents the estimation of crack depth by analyzing temperatures extracted from thermal images and environmental parameters such as air temperature, air humidity, illumination. The statistics of all acquired features and the correlation coefficient among thermal images and environmental parameters are presented. The concrete crack depths were predicted by four different machine learning models: Multi-Layer Perceptron (MLP), Random Forest (RF), Gradient Boosting (GB), and AdaBoost (AB). The machine learning algorithms are validated by the coefficient of determination, accuracy, and Mean Absolute Percentage Error (MAPE). The AB model had a great performance among the four models due to the non-linearity of features and weak learner aggregation with weights on misclassified data. The maximum depth 11 of the base estimator in the AB model is efficient with high performance with 97.6% of accuracy and 0.07% of MAPE. Feature importances, permutation importance, and partial dependence are analyzed in the AB model. The results show that the marginal effect of air humidity, crack depth, and crack temperature in order is higher than that of the others.
        4,300원
        5.
        2014.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        췌장의 신경내분비종양은 매우 드문 종양이나 최근 영상 검사가 발전하면서 진단 빈도도 증가하고 있다. 하지만 세로 토닌 분비 신경내분비 종양은 매우 서서히 진행하고 임상 양 상이 뚜렷하지 않아 진단에 어려움이 있다. 영상검사에서 폐 쇄 병변 없이 췌관 확장만 7년 동안 서서히 진행하여 췌관내 유두상 점액종양으로 의심하였던 환자에서 세로토닌 분비 신경내분비종양으로 수술 후 뒤 늦게 진단하였기에 이를 보고 하는 바이다.
        4,000원
        6.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        2012년 2월부터 11월까지 인천 지역에서 유통된 건고추 및 고춧가루 193건을 대상으로 아플라톡신 B1과 오크라톡 신 A의 오염도를 조사하였다. Immunoaffinity column 및 HPLC를 이용한 시험법은 모두 80% 이상의 회수율을 보였고, 아플라톡신 B1 및 오크라톡신 A의 검출한계는 각각 0.13 μg/kg, 0.30 μg/kg였다. 오염도 조사를 한 결과 아플라 톡신 B1은 17.1%의 검출율을 보였고 오크라톡신 A는 20.7% 의 검출율을 보였으며, 아플라톡신 B1의 검출농도는 0.14~ 9.67 μg/kg였고, 오크라톡신 A의 검출 농도는 0.31~3.31 μg/ kg였다. 이는 우리나라 식품공전 상의 기준인 10 μg/kg(아 플라톡신 B1), 7 μg/kg(오크라톡신 A)보다는 낮은 수치로 비교적 안전한 수준이었다.
        4,000원
        7.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate for mineral contents, total polyphenol compounds,betaine, choline and DPPH free radical scavenging activity of halophyte. The mineral concentrations of Salicornia herbacea (top part) were Na 100,006 mg/kg, K 1,385 mg/kg, Mg 6,263 mg/kg, Ca 2,750 mg/kg, Fe 90.4 mg/kg, Mn 98.9 mg/kg, Zn 33.3 mg/kg, Cu 3.4 mg/kg respectively. And Suaeda Japonica (top part) were Na 85,332 mg/kg, K 710 mg/kg, Mg 7,005 mg/kg, Ca 4,344 mg/kg, Fe 1,434.9 mg/kg, Mn 119.1 mg/kg, Zn 19.2 mg/kg, Cu 2.7 mg/kg respectively. The betaine contents of Salicornia herbacea (top part) were 15.09 mg/g and Suaeda Japonica (top part)were 14.64 mg/g. The choline contents estimated by the DBAP-choline derivatives of Salicornia herbacea (top part)were 20.9 mg/100 g, Salicornia herbacea (root) were 23.4 mg/100 g, Suaeda Japonica (top part) were 23.1 mg/100g and Suaeda Japonica (root) were 23.8 mg/100 g. Total polyphenol compounds of Salicornia herbacea (top part) were high 36.0 mg/g in growth phase. The DPPH radical scavenging activities of methanol extract Salicornia herbacea (top part) were high 90.1% in growth phase. The frozen dried powder of Salicornia herbacea (top part) 1 g was equal to Quercetin 30.26 mg, Rutin 42.65 mg, TBHQ 20.32 mg, BHA 25.86 mg, BHT 40.75 mg, Ascorbic acid 22.86 mg in DPPH radical scavenging activities.
        4,000원
        8.
        2008.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the removal efficiency of 24 odorous compounds was measured in diverse control process units of 7 individual chemical companies located in Ban-Wall & Shi-Wha Industrial Complex in Gyeonggi-do, Korea from March to August, 2007. To quantify the removal efficiency rates of major odorous compounds, we collected odor samples from the inside process and both the front and rear side of 7 control process units. As the results of this study, it was shown that toluene, ammonia, trimethylamine (TMA) and acetaldehyde were dominant odorous compounds in the inside process. In addition, VOCs, TMA and acetaldehyde were also detected at higher concentrations in the stacks and 10 (toluene, acetone, ethyl benzene, xylene etc.) out of 24 index compounds were found to have negative removal efficiencies. According to the removal efficiency evaluation of seven odor control facilities, a company equipped with two connected absorption processes was shown to have positive (+) removal efficiencies for 16 odor substances and NH₃, TMA, acetaldehyde, the priority odor substances, which meant the proper control system was installed and operated. Hence, to obtain best removal efficiency of odorous pollutant emission, the database on source characteristics and the development of management techniques of diverse control process units are continually needed.
        4,000원
        9.
        2007.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to evaluate the dilution accuracy of the dynamic olfactometer made in Republic of Korea and analyze the correlation of odor levels from the olfactometry method and Liquid Chromatography/Mass Spectrometry (LC/MS). The evaluation of dilution accuracy using CH₄ standard gas for the dynamic olfactometer at lower dilution ratios of 3, 10, 30, 100 and 300, and at higher dilution ratios of 100, 300, 1000, 3000 and 10000 showed the relative errors of 1.48~3.40% and 2.06~4.76% respectively showing a good dilution accuracy. Twenty odor samples from the stacks of odor-monitoring factories in the industrial complex located at the western coastal area of ROK were analyzed with the dynamic olfactometer for complex odor and LC/MS for five types of aldehydes, and a very weak correlation of R² = 0.1276 between OU(Odor Unit) from the olfactometer data and SOQ (Summation of Odor Quotient) from LCjMS data was obtained. Because of the complexity of the odor composition, using concentration of single or group of gases to represent odor level has not been proved to fully estimate the presence or level of odors. Therefore, the dynamic olfactometry which has a good dilution accuracy and a standardized odor evaluation system is considered as a very resonable method to assess complex odor.
        4,000원
        11.
        1996.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        차세대 소자고립구조로서 연구되고 있는 trench isolation 공정 등에는 실리콘 식각이 요구되며 실리콘 식각 공정중에는 반응성 이온에 의해 격자결함이 발생할 수 있다. 이와같이 생성된 결함은 소자의 전기적 성질을 열화시키므로 열처리를 통하여 제거하여야만 한다. 따라서 본 연구에서는 Ar,Ar/H2 플라즈마로 격자결함을 인위적으로 발생시켜 200˚C-1100˚C 질소분위기에서 30분간 열처리에 따른 생성된 격자결함의 소거거동을 관찰하였다. 실리콘 표면에 Schottky 다이오드를 제작하여 I-V, C-V 특성을 측정하므로써 잔류하는 전기적인 손상의 정도를 평가하였다. Ar으로 식각한 경우에는 1100˚C 30분간 열처리한 결과 모든 격자결함이 제거되나 Ar/H2로 식각한 경우에는 격자결함이 완전히 제거되지 않고 (111)적층결함이 남아있었다.
        4,000원
        12.
        2015.12 KCI 등재 서비스 종료(열람 제한)
        피부는 외부 유해물질로부터 내부기관을 보호하는 장벽기능을 하는 대표적인 기관으로 자외선 (ultraviolet radiation, UV), 중금속, 각종 산화 물질들과 같은 외부의 위협에 항상 노출되어 있어 손상을 받 기 쉽다. 특히 자외선 B (UVB)는 진피의 상부까지 도달하여 화상이나 홍반과 같은 염증반응을 일으키며 멜라 닌 생성을 촉진시켜 색소 침착을 유발한다. 지나친 자외선 B의 피부세포로의 유입은 각질세포 및 진피 섬유아 세포의 DNA손상을 야기하고, 세포외기질의 합성을 방해하여 피부탄력감소, 주름생성, 진피 결합조직의 손상 과 함께 피부장벽을 붕괴시켜 노화를 일으키며, 장기간 노출 시 심각한 피부 병변으로 이어져 피부세포 사멸 및 종양의 발생으로까지 이어진다. Haloarcula vallismortis는 사해로부터 분리 동정한 미생물로 호염성 고생 물의 생장적 특징은 아직 자세히 연구된 바는 없다. 대게 10% 이상의 염도에서 자라는데 실제 생장염도는 평균 20 ∼ 25% 염도에서 자란다. 염도가 높은 호수나 염전에서 주로 발견되기 때문에 강한 햇빛에 대한 방 어기작이 존재한다. 그중 하나로 다른 ATP를 생성하기 위한 bacteriorhodopsin외에 halorhodopsin이라는 색소를 이용, 광자(photon)를 흡수하고 염화이온 채널을 개방시켜 생기는 전위차를 이용해 추가로 에너지를 생산한다. 또 carotenoid 색소로 인해 농도가 높을시 분홍색 또는 빨간색을 띄는 특징이 있는데 이것이 강한 자외선에 대한 방어기작을 할 것이라고 여겨진다. 본 연구는 호염성 고세균이 자외선을 에너지 소스로 이용하 는 특성을 이용하여 자외선으로부터 피부를 방어하는 방법을 개발하고자 이들의 피부각질세포에서 자외선에 의한 항염 효과 및 DNA 손상 방어 효과를 확인하였다. 그리고 이들을 천연 자외선 차단제의 소재로서 사용 할 수 있음을 확인하였다.
        13.
        2014.05 KCI 등재 서비스 종료(열람 제한)
        In this study, ibuprofen(IBP) degradation by the photochemical (UV/S2O8 2-) and sonochemical (US/S2O8 2-) processes was examined under various parameters, such as UV (10~40±5 W/L) and US (50~90±5 W/L) power density, optimum dosage of persulfate ion (S2O8 2-), temperature (20~60℃) and anions effect (Cl-, HCO3 -, CO3 2-). The pseudo‐first‐order degradation rate constants were in the order of 10-1 to 10-5 min-1 depending on each processes. The synergistic effect of IBP degradation in UV/S2O8 2- and US/S2O8 2- processes could investigated, due to the generation of SO4 - radical. This result can confirm from the produced H2O2 and SO4 2- concentration in each processes. IBP degradation rate affected by the S2O8 2- dosage, temperature, power and anion existence parameters. In particular, IBP degradation rate increased with the increase of the temperature (60℃) and applied power density (UV:40±5 W/L, US:90±5 W/L). On the other hand, anions effect on the IBP degradation was negative, due to the anion play as a the scavenger of radical.
        14.
        2012.07 KCI 등재 서비스 종료(열람 제한)
        Diethyl phthalate (DEP) is widely spread in the natural environment as an endocrine disruption chemicals (EDs). Therefore, in this study, ultrasound (US) and ultraviolet (UVC), including various applied power density (10-40 W/L), UV wavelengths (365 nm, 254 nm and 185 nm) and frequencies (283 kHz, 935 kHz) were applied to a DEP contaminated solution. The pseudo-first order degradation rate constants were in the order of 10-1 to 10-4 min-1 depending on the processes. Photolytic and sonophotolytic DEP degradation rate also were high at shortest UV wavelength (VUV) due to the higher energy of photons, higher molar absorption coefficient of DEP and increased hydroxyl radical generation from homolysis of water. Sonolytic DEP degradation rate increased with increase of applied input power and the dominant reaction mechanism of DEP in sonolysis was estimated as hydroxyl radical reaction by the addition of t-BuOH, which is a common hydroxyl radical scavenger. Moreover, synergistic effect of were also observed for sonophotolytic degradation with various UV irradiation.
        15.
        2012.04 KCI 등재 서비스 종료(열람 제한)
        In this study, Ibuprofen (IBP) degradation by the photo catalytic process was investigated under various parameters, such as UV intensity, optimum dosage of TiO2, alkalinity, temperature and pH of bulk solution. The pseudo-first order degradation rate constants were in the order of 10-1 to 10-4 min-1 depending on each condition. The Photocatalytic IBP degradation rate increased with an increase in the applied UV power. At high UV intensity a high rate of tri-iodide (I3 -) ion formation was also observed. Moreover, in order to avoid the use of an excess catalyst, the optimum dosage of catalyst under the various UV intensities (30 and 40 W/L) was examined and ranged from approximately 0.1 gL-1. The photo catalytic IBP degradation rate was changed depending on the alkalinity and temperature and pH in the aqueous solution. This study demonstrated the potential of photo catalytic IBP degradation under different conditions.
        16.
        2011.02 KCI 등재 서비스 종료(열람 제한)
        In this research, equilibrium of adsorption and kinetics of As(V) removal were investigated. The coal mine drainage sludge(CMDS) was used as adsorbent. To find out the physical and chemical properties of CMDS, XRD (X-ray diffraction), XRF (X-ray fluorescence spectrometer) analysis were carried out. The CMDS was consist of 70% of goethite and 30% of calcite. From the results, an adsorption mechanism of As(V) with CMDS was dominated by iron oxides. Langmuir adsorption isotherm model was fitted well more than Freundlich isotherm adsorption model. Adsorption capacities of CMDS 1 was not different with CMDS 2 on aspect of amounts of arsenic adsorbed. The maximum adsorption amount of two CMDS were respectively 40.816, 39.682 mg/g. However, the kinetic of two CMDS was different. The kinetic was followed pseudo second order model than pseudo first order model. Concentrations of arsenic in all segments of the polymer in CMDS 2 does not have a constant value, but the rate was greater than the value of CMDS 1. Therefore, CMDS 2, which is containing polymer, is more effective for adsorbent to remove As(V).
        17.
        2011.02 KCI 등재 서비스 종료(열람 제한)
        Diethyl phthalate (DEP) and nonylphenol (NP) are widely spread in the natural environment as an endocrine disruption chemicals (EDs). Therefore, in this study, ultrasound (US) and ultraviolet (UVC), including TiO2, as advanced oxidation processes (AOPs) were applied to a DEP and NP contaminated solution. When only the application of US, the optimum frequency for significant DEP degradation and a high rate of hydrogen peroxide (H2O2) formation was 283 kHz. We know that the main mechanism of DEP degradation is radical reaction and, NP can be affected by both of radical reaction and pyrolysis through only US (sonolysis) process and combined US+UVC (sonophotolysis) process. At combined AOPs (sonophotolysis/sonophotocatalysis) such as US+UVC and US+UVC+TiO2, significant degradation of DEP and NP were observed. Enhancement effect of sonophotolysis and sonophotocatalysis system of DEP and NP were 1.68/1.38 and 0.99/1.17, respectively. From these results, combined sonophotocatalytic process could be more efficient system to obtain a significant DEP and NP degradation.
        18.
        2010.03 KCI 등재 서비스 종료(열람 제한)
        Sediments of Little Scioto (LS) River in Ohio was contaminated by poor disposal of creosote from Baker Wood Creosoting Facility. Among the primary compounds of creosote, Polycyclic Aromatic Hydrocarbons (PAHs) are the most common ingredient. PAHs are known for toxic, carcinogenic and mutagenic compounds. There are many difficulties to remove the PAHs in nature environment because their characteristics are having a less water-solubility, volatile and low mobility properties as increasing the molecular weight. The generation of hydroxyl radicals (ㆍOH) and hydrogen peroxide (H2O2) forms as well as high temperature (5000 K) and pressure (1000 atm) by a physico-chemical effects of ultrasound during a cavitation collapse can promote the degradation and desorption of PAHs in sediment And it can also produces shock wave and microjets which are able to change the size and surface of particle in solid-liquid system as one of physical effects. Therefore, we explored to understand the role of particle size, the effect of elimination for PAHs concentration by ultrasound and optimize the conditions for ultrasonic treatment. The condition of various size of particles ( > 150㎛, < 150㎛) and solid-liquid ratio (12.5g/L, 25g/L) for the treatment was considered and ultrasonic power (430 W/L) with liquid – hexane extraction and microwave extraction method were applied after ultrasound treatment.
        19.
        2010.02 KCI 등재 서비스 종료(열람 제한)
        A stabilization/solidification (S/S) process for lead (Pb) contaminated soils was evaluated using waste cow bone containing apatite like compounds. Soil samples obtained form firing range were treated with waste cow bone. The effectiveness of stabilization was evaluated based on the Korean Standard Leaching Test (KSLT) and soil pH. The leached concentration reduced with increased in dose of waste cow bone. Overall, the KSLT results showed that Pb concentration in soils are significantly affected by amount of waste cow bone. When soil amended with 20 % of waste cow bone, less than 0.1 mg/kg was leached, and soil pH was increased from 6.5 to 8.4. Same results were obtained when finer waste cow bone was applied. The reachable concentration of Pb in soil showed in inversely proportional to solid/liquid ratio. Aging periods indicate improving mix design was applied. Relatively high lead concentrations was observed at the first 1 days, however leaching profile are reduced significantly over time for all mix designs.
        20.
        2010.02 KCI 등재 서비스 종료(열람 제한)
        Ultrasound and Surfactant aided soil washing process has been shown to be an effective method to remove diesel from soils. The use of surfactants can improve the mobility of diesel in soil-water systems by increasing solubility of adsorbed diesel into surfactant micelles. However, a large amount of surfactant is required for treatment. In addition, synthetic surfactants, specially anionic, are more toxic and the surfactant wastewater is hard to treat by conventional wastewater treatments even by AOPs. Ultrasound improves desorption of the diesel adsorbed on to soil. The mechanisms are based on physical breakage of bonds by hot spot, directly impact onto soil particle surface, the fragmentation of long-chain hydrocarbons by micro-jet and microstreaming in the soil pores. The use of ultrasound as an enhancement method in both anionic and nonionic surfactant aided soil-washing processes were studied. And all experiments were examined proceeded under CMC surfactant concentration, frequency 35 khz, power 400 W, Soil-water ratio 1:3(wt%), particle size 0.24 ~ 2mm and initial diesel concentration. 20,000 mg/kg. Combination with ultrasound showed significant enhancements on all the processes. Especially, nonionic surfactant Triton-X100 with ultrasound showed remarkable enhancements and diesel removal rate enhanced by ultrasound helps desorpting of surfactant adsorbed onto soils which prevented decreasing surfactant activity.
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