• Journal of Korea Water Resources Association
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• v.55 no.2
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• pp.111-120
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• 2022

The concept of soil moisture memory was used as a method for quantifying the function of soil to control water flow, which evaluates the average residence time of precipitation. In order to characterize the soil moisture memory, a new measurement index called stored precipitation fraction (F_p(f)) was used by tracking the increments in soil moisture by the precipitation event. In this study, the temporal and spatial distribution of soil moisture memory was evaluated along with the slope and soil characteristics of the surface (0~5 cm) soil by using satellite- and model-based precipitation and soil moisture in the Korean peninsula, from 2019 to 2020. The spatial deviation of the soil moisture memory was large as the stored precipitation fraction in the soil decreased preferentially along the mountain range at the beginning (after 3 hours), and the deviation decreased overall after 24 hours. The stored precipitation fraction in the soil clearly decreased as the slope increased, and the effect of drainage of water in the soil according to the composition ratio of the soil particle size was also shown. In addition, average soil moisture contributed to the increase and decrease of hydraulic conductivity, and the rate of rainfall transfer to the depths affected the stored precipitation fraction. It is expected that the results of this study will greatly contribute in clarifying the relationship between soil moisture memory and surface characteristics (slope, soil characteristics) and understanding spatio-temporal variation of soil moisture.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.8
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• pp.877-885
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• 2013

A seawater pipe of the engine room in the ships is being surrounded with severely corrosive environments caused by fast flowing of the seawater, containing aggressive chloride ion and high conductivity etc.. Therefore, the leakage of the seawater from its pipe have been often occurred due to its local corrosion by aggressive chloride ions. Subsequently, its leakage area is usually welded by AC shielded metal arc welding with various electrodes. In this study, when the sea water pipe is welded with several types of electrodes such as E4301, E4311, E4313 and E4316, a difference of the corrosion resistance on the welding metal zones was investigated using an electrochemical method, observing microstructure, measuring polarization behaviors and hardness. The weld metal zone welded with E4313 electrode exhibited the lowest value of hardness compared to other weld metal zones. In addition, its zone indicated also the best corrosion resistance than those of other weld metal zones. Furthermore, all of the weld metal zones revealed a relatively better corrosion resistance than those of the base metal zones. and also showed higher hardness than the base metal zones.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.4
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• pp.84-93
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• 2016

The signal characteristic of radar wave on concrete decks is determined by the attenuation of the radar due to the conversion of EM(Electromagnetic) energy to thermal energy through electrical conduction, dielectric relaxation, scattering, and geometric spreading. In this study, it is found that the attenuation of radar signal received on top rebars in bare deck concrete with 2 way travel time shows a general decreasing linear trend because of its same relative permittivity and conductivity. The radar signal after depth-normalization, can then be interpreted as being principally influenced by the content of chlorides penetrating cover concrete, which caused corrosion of rebars in bridge decks.

• Journal of Korean Society of Disaster and Security
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• v.16 no.3
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• pp.17-26
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• 2023

Prestressed Concrete (PSC) girders are divided into pre- and post-tension types as prestressing method, and I- and U-type as cross-sectional shape. There are both advantages and disadvantages depending on each prestressing method and cross-sectional shape, and each method is applied to bridge construction sites. In this study, a new girder design was attempted to develop that overcomes its shortcomings by using the pretension method and U-type cross sectional shape. Its structural performance was verified in this study. Pretension type girders are mainly manufactured in factories because they require a reaction arm and related facilities, and have the disadvantage of being limited in weight and span length for road transportation. In addition, in the case of the U-type cross-section, structural stability is very reliable during construction against overturning, but its own weight is relatively large comparing to I-type, and the post-tension method is mainly applied after on-site production. In this study, a PSC girder manufacturing method using the field pretension was proposed and a span length of 40 m real-scale test specimen was manufactured and verified its structural performance.

• Journal of Haehwa Medicine
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• v.5 no.2
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• pp.501-501
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• 1997

당뇨병성(糖尿病性) 주위신경병변(周圍神經病變)은 당뇨병(糖尿病)에서 가장 많이 볼 수 있는 삼대합병증(三大合倂症) 중(中)의 하나이다. 환자(患者)의 임상표현(臨床表現)은 사고(四股) 및 구간부(軀幹部)가 마목(麻木)하고,동통(疼痛)이 칼로 베는 듯하거나 침(鍼)으로 찌르는 듯하여 참기 힘들며, 환자(患者)로 하여금 작업능력(作業能力)을 상실(喪失)하게 하고 휴식(休息)과 수안(睡眼)에 엄중(嚴重)한 영향(影響)을 준다. 지금까지 국내외(國內外)에서는 아직 효과적(效果的)인 치료방법(治療方法)이 없다. 우리는 임상(臨床)에서 관찰(觀察)해 본 결과(結果), 이 병(病)의 임상표현(臨床表現)인 "사고마목(四股麻木), 자통(刺痛), 야간가중(夜間加重), 통처고정(痛處固定)"의 특징(特徵)이 중의임상(中醫臨床)에서 표현(表現)되는 "혈어형(血瘀型)" 동통(疼痛)과 완전(完全)히 상동(上同)하였다. 우리는 "활혈화어(活血化瘀), 통락지통(通絡止痛), 거어생신(祛瘀生新)"을 치료원칙(治療原則)으로 중약복방(中藥復方) 제제(制劑) "당말녕(糖末寧)"을 제조(製造)하여 이 병(病)을 치료(治療)하는데 만족(滿足)스러운 임상치료효과(臨床治療效果)를 거두었다. 전체(全體)의 병례(病例)는 모두 우리 과(科)의 입원환자(入院患者)로써 모두 45례(例)인데, 병기(病機)에 따라 양조(兩組)로 나누었다. 관찰조(觀察組) 30례(例) 중(中)에는 남성(男性)이 19례(例)이고 여성(女性)이 12례(例)이며, 年齡(연령)은 25세(歲)에서 68세(歲)까지로 평균연령(平均年齡)이 49.8세(歲)이다. I형(型) 당뇨병(糖尿病)이 10례(例)이고 II형(型) 당뇨병(糖尿病)이 20례(例)이며, 당뇨병(糖尿病)의 병정(病程)은 6개월(個月)에서 17년(年)사이로 평균(平均) 7.1 년(年)이다. 주위신경병변(周圍神經病變)의 병정(病程)은 2주(周)에서 3년(年)까지로 평균(平均) 1년(年)이다. 대조조(對照組)는 15례(例)로 남성(男性)이 8례(例)이고 여성(女性)이 7례(例)이며, 연령(年齡)은 20세(歲)에서 65세(歲)까지로 평균(平均) 49세(歲)이다. I형(型) 당뇨병(糖尿病)이 7례(例)이고 II형(型) 당뇨병(糖尿病)이 8례(例)이며, 橋民病의 병정(病程)은 3개월(個月)에서 12년(年)까지로 평균(平均) 7.5년(年)이다. 주위신경병변(周圍神經病變)의 병정(病程)은 1개월(個月)에서 3년(年)까지로 평균병정(平均病程)은 11.6개월(個月)이다. 양조(兩組)사이의 병정(病程)은 현저(顯著)한 차이는 없으나 서로 비교(比較)해 볼만하다. 당말녕(糖末寧)은 주(主)로 삼궁(三芎),원호(元胡), 당귀(當歸), 계혈승 등(等)의 약물(藥物)로 조성(組成)되었고, 약제실(藥劑室)에서 濃縮液(농축액)(매(每) ml당(當) 생약량(生藥量) 2.5g 함유(含有))으로 제조(製造)하였다. 관찰조(觀察組)는 매차례(每次例) 당말녕(糖末寧) 50ml를 하루 세번씩 복용(服用)하였고; 대조조(對照組)는 비타민 $B_1$, 비타민 $B_6$을 각각(各各) 20mg씩 하루 세차례 복용(服用)하였다. 양조(兩組) 모두 사주(四周)를 한번의 치료료정(治療療程)으로 하였다. 우리는 모두 45례(例)의 환자(患者)를 관찰(觀察)하였는데, 그 중(中) 관찰조(觀察組)가 30례(例)이고 대조조(對照組)가 15례(例)이다. 임상표현(臨床表現) 분급(分級)과 신경근전도(神經筋電圖)(운동신경(運動神經)과 감각신경(感覺神經)의 전도(電圖) 속도(速度))를 치료(治療) 전(前)과 후(後)의 대조지표(對照指標)로 하였고. 매(每) 4주(周)를 한개의 료정(療程)으로 총(總) 1-2개(個)의 료정(療程)을 진행(進行)하여 比較硏究(비교연구)하였다. 총유효율(總有效率)은 96.7%이고 총현효율(總顯效率)은 50%로써 대조조(對照組)보다 뚜렷하게 높았다. 치료전(治療前) MNCV와 SNCV를 측정(測定)한 것은 당말녕(糖末寧)이 당뇨병(糖尿病) 주위신경병변(周圍神經病變) 환자(患者)의 신경전도속도(神經電圖速度)를 명확(明確)하게 개선(改善)하였음을 표현(表現)하고 있다. 신경근전도(神經筋電圖)에서 자발전위(自發電位)는 눈에 띄게 감소(減少)되고 소력수축(小力收縮)의 평균시한(平均時限)은 명확(明確)히 연장(延長)되었으며 다상전위(多相電位)는 명확(明確)하게 증가(增加)되었는데, 이는 신경지측(神經支測)이 재생(再生)되고 회복(恢復)하였음을 설명(說明)하고 있다. 중약복방제제(中藥復方制劑) "당말녕(糖末寧)"이 본병(本病)을 치료(治療)하는 기전(機轉)은 여러 방면(方面)일 것이다. 그 중(中) 微循環(미순환)을 개선(改善)하고 적혈구(赤血球)의 변형성(變形性)을 향상(向上)하여 신경세포(神經細胞)에 혈액(血液)과 산소공급(酸素供給) 및 영양공급(營養供給)을 향상(向上)함으로써 神經損傷(신경손상)의 수정(修整)과 회복(恢復)을 촉진(促進)하는 것이 주요(主要)한 일환(一環)이 될 것이다.

• Journal of Radiation Protection and Research
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• v.24 no.2
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• pp.73-86
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• 1999

The ion-exchange method for the purification of primary coolant has been used broadly in PWR(pressurized water reactor)-type nuclear power plants due to its high decontamination efficiency, simple system, and easy operation. However, its non-selective removal of metal and non-radionuclides shortens its life, resulting in the generation of a large amount of waste ion-exchange resin. In this study, the feasibility of electrodeionization (EDI) was investigated for the purification of primary cooling water using synthetic solutions under various experimental conditions as an alternative method for the ion exchange. The results shows that as the feed flow-rate increased, the removal efficiency increased and the power consumption decreased. The removal rate was observed as a 1000 decontamination factor(DF) at a nearly constant level. For the synthetic solution of 3 ppm TDS (Total Dissolved Solid), the power consumption was 40.3 mWh/L at 2.0 L/min of feed flow rate. The higher removal rate of metal species and lower power consumption were obtained with greater resin volume per diluting compartment. However, the flow rate of the EDI process decreased with the elapsed time because of the hydrodynamic resistivity of resin itself and resin fouling by suspended solids. Thus, the ion-exchange resin was replaced by an ion-conducting spacer in order to overcome the drawback. The system equipped with the ion-conducting spacer resolved the problem of the decreasing flow rate but showed a lower efficiency in terms of the power consumption, the removal rate of metal species and current efficiency. In the repeated batch operation, it was found that the removal efficiency of metal species was stably maintained at DF 1000.