• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.5
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• pp.401-412
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• 2016

It is extremely difficult to apply conventional grouting methods to subsea tunnelling construction in the high water pressure condition. In such a condition, the rapid artificial freezing method can be an alternative to grouting to form a watertight zone around freezing pipes. For a proper design of the artificial freezing method, the influence of salinity on the freezing process has to be considered. However, there are few domestic tunnel construction that adopted the artificial freezing method, and influential factors on the freezing of the soil are not clearly identified. In this paper, a series of laboratory experiments were performed to identify the physical characteristics of frozen soil. Thermal conductivity of the frozen and unfrozen soil samples was measured through the thermal sensor adopting transient hot-wire method. Moreover, a lab-scale freezing chamber was devised to simulate freezing process of silica sand with consideration of the salinity of pore-water. The temperature in the silica sand sample was measured during the freezing process to evaluate the effect of pore-water salinity on the frozen rate that is one of the key parameters in designing the artificial freezing method in subsea tunnelling. In case of unfrozen soil, the soil samples saturated with fresh water (salinity of 0%) and brine water (salinity of 3.5%) showed a similar value of thermal conductivity. However, the frozen soil sample saturated with brine water led to the thermal conductivity notably higher than that of fresh water, which corresponds to the fact that the freezing rate of brine water was greater than that of fresh water in the freezing chamber test.

• Journal of Soil and Groundwater Environment
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• v.12 no.5
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• pp.19-32
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• 2007

In Korea, there have been various methods of estimating groundwater recharge which generally can be subdivided into three types: baseflow separation method by means of groundwater recession curve, water budget analysis based on lumped conceptual model in watershed, and water table fluctuation method (WTF) by using the data from groundwater monitoring wells. However, groundwater recharge rate shows the spatial-temporal variability due to climatic condition, land use and hydrogeological heterogeneity, so these methods have various limits to deal with these characteristics. To overcome these limitations, we present a new method of estimating recharge based on water balance components from the SWAT-MODFLOW which is an integrated surface-ground water model. Groundwater levels in the interest area close to the stream have dynamics similar to stream flow, whereas levels further upslope respond to precipitation with a delay. As these behaviours are related to the physical process of recharge, it is needed to account for the time delay in aquifer recharge once the water exits the soil profile to represent these features. In SWAT, a single linear reservoir storage module with an exponential decay weighting function is used to compute the recharge from soil to aquifer on a given day. However, this module has some limitations expressing recharge variation when the delay time is too long and transient recharge trend does not match to the groundwater table time series, the multi-reservoir storage routing module which represents more realistic time delay through vadose zone is newly suggested in this study. In this module, the parameter related to the delay time should be optimized by checking the correlation between simulated recharge and observed groundwater levels. The final step of this procedure is to compare simulated groundwater table with observed one as well as to compare simulated watershed runoff with observed one. This method is applied to Mihocheon watershed in Korea for the purpose of testing the procedure of proper estimation of spatio-temporal groundwater recharge distribution. As the newly suggested method of estimating recharge has the advantages of effectiveness of watershed model as well as the accuracy of WTF method, the estimated daily recharge rate would be an advanced quantity reflecting the heterogeneity of hydrogeology, climatic condition, land use as well as physical behaviour of water in soil layers and aquifers.

• Radiation Oncology Journal
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• v.11 no.1
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• pp.97-102
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• 1993

A retrospective analysis of various characteristics in 32 limited stage small cell lung cancer patients treated at the Department of Therapeutic Radiology in Kangnam St. Mary's Hospital, Catholic University Medical College from April 1983 to September 1991, was carried out to identify factors which had prognostic significance for survival from initiation of radiation therapy. There were 26 men and 6 women. Median age was 63 years (range: 24-78 years). The follow up duration was 1.5 to 44 months (median: 9 months). External radiation therapy was done with daily 160-180 cGy,5 fraction/week, total of 1000-6660 cGy (median: 4500 cGy) to the mediastinum by 6 MV linear accelerator. Of 32 Patients, 27 ($84.4{\%}$) patients were treated with combined modality (chemotherapy plus radiation therapy), and 5 ($15.6{\%}$) patients were treated with radiation therapy only. Complete responders were 12 patients ($37.5{\%}$), partial responders were 11 ($34.4{\%}$), and no responders were 9($28.1{\%}$). Karnofsky performance status over 70 (p<0.04), chemotherapy regimen (CAV, PV, and CAV+PV) (p<0.04),6 or more cycles of chemotherapy (p<0.007), radiation therapy over 4500 cGy (p<0.03), and radiation therapy responder (CR+PR) (p<0.003) showed a significantly favorable influence on 1 year survival rate. Age (p=0.545), sex (p=0.666), presence of superior vena cava syndrome (p=0.719), prophylactic cranial irradiation (p=0.217), and radiation therapy duration (p=0.491) had no effect on survival. Radiation induced side effects were transient esophagitis in 11 ($34{\%}$), general weakness in 9($28{\%}$), gastrointestinal symptoms in terms of nausea, vomiting and indigestion in 5 ($15{\%}$) and leukopenia in 1 ($3{\%}$).

• Journal of the Korean Electrochemical Society
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• v.13 no.2
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• pp.116-122
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• 2010

A $Cu_3Si$ film electrode is obtained by Si deposition on a Cu foil using DC magnetron sputtering, which is followed by annealing at $800^{\circ}C$ for 10 h. The Si component in $Cu_3Si$ is inactive for lithiation at ambient temperature. The linear sweep thermammetry (LSTA) and galvano-static charge/discharge cycling, however, consistently illustrate that $Cu_3Si$ becomes active for the conversion-type lithiation reaction at elevated temperatures (> $85^{\circ}C$). The $Cu_3Si$ electrode that is short-circuited with Li metal for one week is converted to a mixture of $Li_{21}Si_5$ and metallic Cu, implying that the Li-Si alloy phase generated at 0.0 V (vs. Li/$Li^+$) at the quasi-equilibrium condition is the most Li-rich $Li_{21}Si_5$. However, the lithiation is not extended to this phase in the constant-current charging (transient or dynamic condition). Upon de-lithiation, the metallic Cu and Si react to be restored back to $Cu_3Si$. The $Cu_3Si$ electrode shows a better cycle performance than an amorphous Si electrode at $120^{\circ}C$, which can be ascribed to the favorable roles provided by the Cu component in $Cu_3Si$. The inactive element (Cu) plays as a buffer against the volume change of Si component, which can minimize the electrode failure by suppressing the detachment of Si from the Cu substrate.

• Journal of the Korean Institute of Gas
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• v.17 no.4
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• pp.58-69
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• 2013

This paper presents production data analysis for two production wells located in the shale gas field, Canada, with the proper analysis method according to each production performance characteristics. In the case A production well, the analysis was performed by applying both time and superposition time because the production history has high variation. Firstly, the flow regimes were classified with a log-log plot, and as a result, only the transient flow was appeared. Then the area of simulated reservoir volume (SRV) analyzed based on flowing material balance plot was calculated to 180 acres of time, and 240 acres of superposition time. And the original gas in place (OGIP) also was estimated to 15, 20 Bscf, respectively. However, as the area of SRV was not analyzed with the boundary dominated flow data, it was regarded as the minimum one. Therefore, the production forecasting was conducted according to variation of b exponent and the area of SRV. As a result, estimated ultimate recovery (EUR) increased 1.2 and 1.4 times respectively depending on b exponent, which was 0.5 and 1. In addition, as the area of SRV increased from 240 to 360 acres, EUR increased 1.3 times. In the case B production well, the formation compressibility and permeability depending on the overburden were applied to the analysis of the overpressured reservoir. In comparison of the case that applied geomechanical factors and the case that did not, the area of SRV was increased 1.4 times, OGIP was increased 1.5 times respectively. As a result of analysis, the prediction of future productivity including OGIP and EUR may be quite different depending on the analysis method. Thus, it was found that proper analysis methods, such as pseudo-time, superposition time, geomechanical factors, need to be applied depending on the production data to gain accurate results.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.2
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• pp.23-36
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• 2010

The purpose of this study is to infer the aspects and significance of Musa basjoo of latter part of Chosun Dynasty by analyzing the planting tendency and planting location of Musa basjoos drawn in total 77 old paintings and the characteristics of the paintings where Musa basjoos appeared, while trying to understand symbolic meanings of floral languages as well as the images and significance of Musa basjoos which appeared in the prose and poetry of Chosun Dynasty, and the results are as follows; With its floral languages of 'waiting', 'parting' and 'beauty', Musa basjoo represented the wealth and resuscitation and it aroused the elegance of hermits in its Taoistic sense. And it also represented 'the unworldliness to get out of transient human affairs' in its Buddhistic sense. Musa basjoos which appeared in 'Garden Custom Painting(庭園雅集圖)', 'Gosa Figure Painting(故事人物圖)' and 'Gyehoe Painting(契會圖)' is considered a device to increase the unworldly atmosphere of gardens and to dignify the elegant meetings of scholars, reflected by the high appearance frequencies of cranes and deer. And it seems that the meaning of Musa basjoo in certain paintings like 'Life-time Paintings(平生圖)', 'Castle City Painting(盛市圖), and 'Cultivating and Weaving Painting(耕織圖)' is an aspiration for wealth and prosperity, and the Musa basjoos planted in temples are considered to have symbolic meanings of aspiration for 'Salvation through Belief' as well as a unworldly meaning which reminds the transiency of human affairs. In addition, the expected effect of experiencing 'the sound of rain falling on the leaves of Musa basjoo' has been pursued, which can be confirmed by the fact that Firmiana simlex with wide leaves similar to Musa basjoo can be frequently spotted near the houses. Meanwhile, Musa basjoos seem to have been planted mainly in front garden or side garden around detached house and Musa basjoos inside the houses seem to have been planted mainly in right side when viewed from the entrance, in relation with the location of bedrooms where it is easier to hear the sounds from the right side of the environment. And the paintings where Musa basjoos appear with strange rocks and bizarre stones among other things have greater part of all the paintings, which is considered a kind of intentional landscaping and a product of mixed materials for elegant appreciation. And the major characters of the painting were involved in the activities of scholars such as arts, and the activities of minor characters were greatly related to their everyday lives. Musa basjoo of Chosun Dynasty in $17^{th}$ and $18^{th}$ century was one of the symbols necessary for description of gardens. And it provided the images of rainy scenes together with scholar culture which had a meaning of self-discipline, and it is assumed that the planting of Musa basjoo with the spirit of cease lessen deavor of a new leaf pushing up the tree and the spirit of resuscitation had the same trace of wheels in the city space of our country as the decline of scholar culture of Chosun Dynasty.

• Pediatric Infection and Vaccine
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• v.5 no.2
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• pp.230-238
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• 1998

Purpose : Worldwidely, the incidence of the hepatitis A has been markedly decreased in the past years. Also in Korea, there has been only a few sporadic cases without evidence of epidemics since the mid 1980s. However, the incidence of the hepatitis A in young adults and childen has been in trends of increasing since 1996. So, we retrospectively performed the study on the epidemiolgical changes and the clinical feature of hepatitis A in childen, living in Kyung-gi province, since 1988 to 1998. Methods : The four affiliated hospitals of the Catholic University of Korea, Our lady of Mercy's hospital, Holy family hospital, Eui-Jung-bu St. Mary's hospital, and St. Vincent hospital, were enrolled in this study. We conducted statistical analysis on the incidence of hepatitis A since 1988 to 1998, concerning with the period (monthly, annually), age, sex and related epidemiological property, by reviewing the hospital records of the patients with hepatitis A. We simultaneously performed the study concerning with the clinical characteristics of hepatitis A. Results : 1) During the study period, 46 children was diagnosed as hepatitis A, and among them 28 children (60.1%) developed sporadically in the 1998. And sex ratio was 1.2(male):1(female). 2) Most of the patients developed between March and July, and hepatitits A were mainly developed in the patients above the 10 year old ages(37 patients; 80.4%). 3) The socioeconomic and educational status of the patient's parents was almostly below the middle and low class. Although, we could not find the etiological factors in most cases, but we found the evidence of interfamilial transmission in one family. 4) The patients complained the symptoms of nausea and vomiting, jaundice, poor appetite, mild fever, fatigueness, abdominal pain, URI symptom, dyspepsia, dark urine, headache and diarrhea in order, and findings of jaundice, hepatomegaly, RUQ tenderness, splenomegaly and LLQ tenderness in order were seen. 5) All patients showed abnormal findings of the liver function tests, and the pattern of cholestatic hepatitis were seen in most cases, but these findings were normalized within the 2~4 weeks. The findings of the gall bladder wall thickening, hepatomegaly, splenomegaly and ascites were seen on abodominal sonogram. 6) The prognosis of all patients were good without complications, except in one case who had the episode of transient recuurence. And the mean hospitalization dates were 11.1 days. Conclusion : We found that the incidence of hepatitis A showed the increasing trend, and peaked in the 1998 in Kyung-gi province children. And hepatitis A mainly developed in children above the 10 year old ages. The scioeconomic and educational status of patient's family was almostly below the middle class. All of them showed abnormal liver function, and clinically cholestatic hepatitis features were seen in most cases. But, the prognosis was excellent without complication in all cases.