• 보존과학회지
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• 제29권4호
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• pp.297-309
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• 2013

철제유물은 출토되는 순간 급격한 환경변화로 인해 빠른 속도로 부식이 진행되므로 보존처리 과정을 거쳐 부식을 억제한다. 그러나 보존처리가 완료된 철제유물도 재부식이 발생하는 경우가 다수이며, 재부식된 유물의 보존처리는 1차 보존처리 시보다 그 처리가 어렵고 처리기간 또한 길어진다. 본 연구는 보존처리가 완료된 이후 보관과정에서 발생하는 부식생성물을 과학적으로 분석하여 재부식의 요인을 찾고자 하였다. 경주지역의 세 유적에서 출토된 철제유물을 동일한 약품과 방법으로 2002~2009년 동안 보존처리를 완료하였으나, 포장 보관 상태의 일부 철제유물에서 재부식 징후가 관찰되었다. 이중 재부식의 징후가 확인된 단조 철제유물 9점을 선별하여 질량측정, 육안관찰, 현미경을 통한 물리적 변화를 관찰하였고, SEM-EDS, XRD, IC, ICP분석을 통해 화학적 변화를 분석하였다. 그 결과, 유물에서 탈락된 부분의 접면에 형성된 황갈색 부식생성물은 군집한 형상만 다를 뿐 결정상은 공통적으로 침상형이 확인되었으며, 적색에서 황갈색으로 갈수록 침상의 형태가 뚜렷하였다. 보존처리가 완료된 시점의 경과에 따라 부식생성물이 증가할수록 유물의 질량이 증가하였고 염화이온의 농도가 상대적으로 높아지는 경향이 나타났다. 채집된 모든 시료의 부식생성물에 대한 XRD분석에서는 ${\beta}$-FeOOH(akaganeite)이 확인되었고, ICP분석 결과 $Na^+$, $Ca^{2+}$성분을 확인할 수 있었다.

• 한국식품영양과학회지
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• 제21권2호
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• pp.213-218
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• 1992

식품의 동결중에 생성되는 빙결정의 크기에 미치는 동결조건의 영향을 조사하고 그 관계를 정량적으로 평가함과 아울러 동결조건과 빙결정 분산구조와의 관계를 이론해석에 의해 조사한 결과, 1. 동결이동속도 u는 생성빙결정의 평균경 d$_{p}$와 u .d$_{p}$/D~constant의 관계에 있음을 간단한 차원해석에 의해 예측이 가능하였다. 2. 2% 한천 겔, 5%한천 겔, 20% 젤라틴 겔, 돈육의 순서로 동결점에 도달하는 시간이 빨라지며 동결시간 및 최대빙결품 생성대의 통과시간은 냉매온도와 선형적인 관계를 나타내었다. 3. 대두 단백질 겔중에 생성되는 빙결정의 평균경 d$_{p}$와 동결계면 이동속도 u 는 반비례 관계를 나타내었으며, 이로부터 구해진 u .d$_{p}$의 값은 3.4$\times$$10^{-6}$ $\textrm{cm}^2$/sec로 예측 이론식이 유효한 것으로 사료되었다. 4. 동결보존중의 대두 단백질 겔 내부에 생성된 빙결정의 성장에 미치는 보존온도의 영향을 조사한 결과, 양자가 빙결정의 성장에 미치는 영향은 거의 없는 것으로 나타났다. 5. 동결조건과 동결계면구조와의 사이에 Moving velocity of freezing front= (Mass transfer rate of water at freezing front)$\times$ (Surface area of freezing front) 의 관계를 나타내었다.

• Environmental Analysis Health and Toxicology
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• 제17권3호
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• pp.197-205
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• 2002

Volatile organic compounds (VOCs) are an important public health problem throughout the world. Many important questions remain to be addressed in assessing exposure to these compounds. Because they are ubiquitous and highly volatile, special techniques must be applied in the analytical determination of VOCs. Personal exposure measurements are needed to evaluate the relationship between microenvironmental concentrations and actual exposures. It is also important to investigate exposure frequency, duration, and intensity, as well as personal exposure characteristics. In addition to air monitoring, biological monitoring may contribute significantly to risk assessment by allowing estimation of absorbed doses, rather than just the external exposure concentrations, which are evaluated by environmental and personal monitoring. This study was conducted to establish the analytic procedure of VOCs in air, blood, urine and exhaled breath and to evaluate the relationships among these environmental media. The subjects of this study were selected because they are occupationally exposed to high levels of VOCs. Environmental, personal, blood, urine and exhalation samples were collected. Purge ＆ trap, thermal desorber, gas chromatography and mass selective detector were used to analyze the collected samples. Analytical procedures were validated with the“break through test”, 'quot;recovery test for storage and transportation”,“method detection limit test”and“inter-laboratory QA/QC study”. Assessment of halogenated compounds indicted that they were significantly correlated to each other (p value < 0.01). In a similar manner, aromatic compounds were also correlated, except in urine sample. Linear regression was used to evaluate the relationships between personal exposures and environmental concentrations. These relationships for aromatic and halogenated are as follows: Halogen $s_{personal}$ = 3.875+0.068Halogen $s_{environmet}$, ($R^2$= .930) Aromatic $s_{personal}$ = 34217.757-31.266Aromatic $s_{environmet}$, ($R^2$= .821) Multiple regression was used to evaluate the relationship between exposures and various exposure deter-minants including, gender, duration of employment, and smoking history. The results of the regression model-ins for halogens in blood and aromatics in urine are as follows: Halogen $s_{blood}$ = 8.181+0.246Halogen $s_{personal}$+3.975Gender ($R^2$= .925), Aromatic $s_{urine}$ = 249.565+0.135Aromatic $s_{personal}$ -5.651 D.S ($R^2$ = .735), In conclusion, we have established analytic procedures for VOC measurement in biological and environmental samples and have presented data demonstrating relationships between VOCs levels in biological media and environmental samples. Abbreviation GC/MS, Gas Chromatography/Mass Spectrometer; VOCs, Volatile Organic Compounds; OVM, Organic Vapor Monitor; TO, Toxic Organicsapor Monitor; TO, Toxic Organics.

• 터널과지하공간
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• 제31권4호
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• pp.243-269
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• 2021

2010년대 이후 고준위 방사성폐기물 심층처분, 지하 CO₂ 저장과 시추공 조사 기반 심지층 특성화를 대상으로 한 연구 및 실용화 프로젝트의 사회적 중요성이 점차 높아지고 있다. 이와 관련하여, 대심도 암반의 수리 특성에 대한 정량적이고 신뢰성있는 정보를 얻을 수 있는 현장 시험 기술의 필요성도 크게 증가하고 있다. 수년간의 연구 개발을 통해 자체 기술력으로 설계, 제작된 핵심 장치들을 기반으로 대심도 시추공 수리특성 조사 시스템(DHTS)을 독자적으로 구축하였다. 이 시스템을 사용하여 경주시 중생대 화강암과 퇴적암 지역에 위치한 심도 1 km 급 시추공 2개소에서 고정밀도 정압 주입시험을 성공적으로 수행하였다. 현장 시험에서 미세 유량 주입/조절 모듈을 사용하여 0.01 l/min 미만의 매우 낮은 유량 측정이 가능하였다. 본 논문에서는 DHTS의 주요 특성을 소개하고 대심도 저투수성 암반 환경 하에서 수행된 고정밀도 시험 결과에 대해 간단히 논의하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권2호
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• pp.260-265
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• 2013

The purpose of this study was to investigate the dietary effects of persimmon peel (PP) and PP ethanol extract (PPE) on egg production, egg quality, and liver lipids in the late stage of egg production in laying hens. One hundred and twenty 50-wk-old Hy-Line Brown layers (n = 120) were fed different diets. Four replicate groups of 6 hens each were randomly assigned to 5 dietary treatments. The 5 dietary treatments were as follows: i) CON, basal diet; ii) PP 0.15, CON+0.15% PP (0.035% tannin); iii) PP 0.5, CON +0.5% PP (0.117% tannin); iv) PPE 0.075, CON+0.075% PPE (0.03% tannin); and v) PPE 0.25, CON+0.25% PPE (0.11% tannin). The total tannin concentration of PPE was higher (p<0.05) than that of PP. Egg production in the PP 0.5 group was higher than in the other groups. Egg production and mass of hens in the PPE 0.25 group showed a greater decrease than that in the other groups (p<0.05). Eggshell color in the PP 0.15, PP 0.5, and PPE 0.075 groups was lighter than that of the control group (p<0.05). The Haugh unit for the groups that were fed PP and PPE were significantly higher than that in the other groups after 7 d of storage (p<0.05). Therefore, PP seems an effective feed additive for improving the production performance and egg quality in late stage laying hens.

• 한국수소및신에너지학회논문집
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• 제5권2호
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• pp.81-90
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• 1994

The hydrogen fuel tanks having hydrogen storing capacity of about 300g and 1200g are manufactured using $MmNi_{4.7}Al_{0.25}V_{0.05}Fe_{0.001}$ alloy. They are composed of several unit reactor made of Cu-tube(outer diameter = 50.1mm, thickness = 2mm). In order to increase the heat and mass transfer property of the hydride bed, Al-plates are inserted perpendicular to axial direction at intervals of 5mm and three arteries of diameter 8mm are installed symmetrically in each unit reactor. Hydrogen absorption is proceeded about 80% within 30 minute and is completed within 60 minute at the conditions of charging hydrogen pressure of 25atm and temperature of $22^{\circ}C$. On desorbing hydrogen at a constant rate of 30 slm at $20^{\circ}C$, discharging hydrogen pressure is sustained at 3~5atm for 120 minutes. The discharging pressure is increased upto 5~8atm as the increase of the reactor temperature to $30^{\circ}C$. From the experimental results and the brief discussions about the hydrogen absorption and disorption behaviors of the hydrogen storage tank, it is suggested that the behaviors of hydrogen charging and discharging could be controlled by adjusting the operating parameters and the reactor design parameters.

• 전산구조공학
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• 제6권4호
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• pp.89-98
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• 1993

최근 원자력의 사용이 증가함에 따라 핵폐기물을 효과적으로 처리하는 문제에 관심이 집중되고 있다. 이러한 핵폐기물을 지층내에 저장할 경우 고온의 열에 의해 핵폐기물 구조체에 지대한 영향을 미치므로 지반의 열력학적 거동을 분석할 필요성이 요구된다. 본 연구는 지반내에 처분된 고온의 사용후 핵연료에 의한 열역학적인 응력이 집중되어 비선형 거동이 예상되는 저장구조체 주변에는 비선형 유한요소를 적용하고 선형거동이 예상되는 무한영역에는 선형경계요소를 사용하여, 일반적인 역학적 계와 동일한 방법으로 비선형 유한요소와 경계요소를 조합한 프로그램을 개발하였다. 사용후 핵연료 폐기구조체와 같이 국부적인 비선형거동이 예상되는 구조물에서는 조합방법이 전 영역을 비선형 유한요소로 모형화하여 해석하는 것보다 효율적임을 알 수 있었다. 또한, 지층내 지반에 영향 미치는 주요 지반계수를 변화시킨 경우, 터널경계의 변위에 이러한 계수들이 어떠한 영향을 미치는가를 개발된 방법을 사용하여 검토하였다. 검토결과, 다른 계수들의 변화보다 열팽창계수의 변화가 터널주위의 변위에 상당한 영향을 미침을 알 수 있었다.

• 터널과지하공간
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• 제2권1호
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• pp.116-122
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• 1992

A comprehensive, nonsteady state, computer simulation program for the environmental conditions in advancing tunnels (the HEADSIM simulation program) is constructed and successfully validated with heat balance amongst all heat sources, and with mass conservation amongst various airflows including the leakage air from ducts, under timedependent variations of inlet air conditions. which include sudden, diurnal and seasonal changes. Heat conduction in the wall strata and face strata is simulated with most complicated boundary conditions using the finite difference method, and the climatic conditions in roadway sections which contain air ducts, booster fan, spray cooler, compressed air pipes, cold water pipes, return water pipes, machinery and broken rock are simulated taking into account the variations of face operation and the heat storage mechanism in the strata. The limitations of simulation time steps and roadway section lengths are defined according to the stability criteria satisfying the principles of thermodynamics. Variations of heat transfer coefficients, which are newly set, and those of wetness factors are taken into account according to the variations of other parameters and the stepwise advance of the face. Newly-derived formulae are used for computing the air duct leakage and the pressure inside of the duct. A new concept of an 'imaginary duct' is introduced to simulate the climatic conditions in tunnels during holiday periods, which directly affect conditions on subsequent working days under the consideration of natural convection. A subsidiary program (the WALLSIM simulation program) is made to compute the dimensionless tunnel surface temperatures and to compare the results with those from analytical approaches, and to demonstrate the stability, convergence and accuracy of the strata heat conduction simulation, adopting the finite difference method. The WALLSIM also has wide applications, including those for the computation of age coefficients.

• Food Science and Biotechnology
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• 제17권5호
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• pp.912-918
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• 2008

This study was conducted to identify the differences in proteomic characteristics of 'Agakong', recombinant inbred line, and its parental genotypes 'Eunhakong' (Glycine max) and 'KLG10084' (G. soja). The isoflavone content of 'Agakong' was 3 times higher than that of its parental lines. A combined high-throughput proteomic approach was employed to determine the expression profile and identity of proteins using 2-dimensional gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. The overall distribution patterns of proteins are quite similar, but lots of protein spot intensities varied among the genotypes. A total of 41 proteins, representing significant difference in the quantities of protein among the lines, were successfully identified. Among them, more than 50% of the proteins identified were subunits of glycinin and $\beta$-conglycinin, 2 major storage proteins. This study showed that the proteomic analysis could help to define specific changes in protein level and composition, which can occur in the generation of new soybean varieties.

• Asian-Australasian Journal of Animal Sciences
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• 제23권11호
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• pp.1503-1509
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• 2010

Forty-eight 40-wk-old Hi-sex laying hens were individually caged in an environmentally controlled house to evaluate the effect of garlic (Allium Sativum) juice administration on egg production, egg quality, and yolk cholesterol. Garlic juice was prepared by blending pealed garlic cloves with distilled water (1:1, w/w). Hens were randomly divided into four equal groups; one served as a control and the other three groups were individually gavaged, 3.75 ml, 7.5 ml, or 15 ml garlic juice, three times a week, which respectively represented 0.25, 0.50 and 1% of body weight. Egg production was recorded on a daily basis; egg weight, albumen height, albumen and yolk pH, Haugh unit, and bacterial count of E. coli-challenged eggs were recorded at day of oviposition (day-1) and after 5 and 10 days of storage at room temperature. Yolk cholesterol content was analyzed for five successive weeks. Garlic juice increased (p<0.05) egg weight and mass with no change in egg production intensity. Garlic juice administration recorded higher (p<0.05) albumen height and improvement in Haugh unit. Also, eggs from garlic-treated hens recorded lower (p<0.05) albumen and yolk pH when compared to eggs collected from control hens. Garlic reduced (p<0.05) the $log_{10}$ of bacterial count in egg contents linearly when challenged with E. coli. Egg-yolk cholesterol content was not influenced by garlic juice administration. It is concluded that garlic juice improved performance characteristics and may increase egg shelf life as indicated by egg quality improvement and lower bacterial count of E. coli-challenged eggs. The levels of garlic juice used in this study were insufficient to influence egg yolk cholesterol.