• Economic and Environmental Geology
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• v.19 no.spc
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• pp.193-206
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• 1986

A number of auriferous veins occur in the Precambrian metamorphic terrain from Chungju to Mugeug district. These gold (-silver) deposits consist mainly of the fissure-filling quartz veins intruding the Precambrian gneiss or schist and Jurassic or Cretaceous granite. These gold (-silver) deposits can be 'divided into two mineralization epochs, (a) gold-rich veins related to Daebo igneous activity, and (b) gold-silver veins related to Bulgugsa igneous activity. These two groups of ore deposits with different generation can be characterized by the mode of occurrence of ore vein and the ore mineral associations. The auriferous quartz veins of Taechang and Boryeon mines associated with late Jurassic igneous activity are massive in character, and show the simple mineral assemblages and low Ag/Au ratio in the ores, representing a single mineralization system. The ore minerals are predominantly quartz containing minor or trace amonts of pyrrhotite, sphalerite, galena, pyrite, chalcopyrite and electrum. Electrum is closely associated with pyrrhotite and has chemical compositions from 61.4 to 78.5 atomic % Au. Fluid inclusion data suggest that ore minerals were deposited at temperatures between 238 and $390^{\circ}C$ from $CO_2$-rich fluids. The gold and/or silver-bearing quartz veins of Geumwang mine related to middle Cretaceous igneous activity are characterized by the multistage history, diverse mineral assemblages with high Ag/Au ratio in the ores. The ores of Geumwang mine have two contrasting mineral assemblages (1) pyrite+galena+sphalerite+arsenopyrite+electrum+argentite, representing the higher gold mineralization, and (2) pyrite+chalcopyrite+ galena +sphalerite+ arsenopyrite+silver sulfosalts+ electrum+ native silver+argentite, representing the higher silver mineralization. Electrum is closely associated with pyrite and has chemical compositions from 11.2 to 49.9 atomic % Au. The depositional environment during the higher gold mineralization can be estimated as the range of both temperature and sulfur fugacity, T= $200{\sim}300^{\circ}C$, log f ($S_2$) = $10^{-10}{\sim}10^{-15}$. The higher silver mineralization may be interpreted to have formed a range of falling temperature ($150{\sim}200^{\circ}C$) and low sulfur fugacity($10^{-10}{\sim}10^{-15}$). These temperature data are consistent with homogenization temperatures of fluId inclusions in quartz. Thus, the gold veins related to the Daebo igneous activity may be formed by the environment of higher temperature and pressure than the gold-silver veins associated with the Bulgugsa igneous activity.

• Journal of the Korea Concrete Institute
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• v.24 no.6
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• pp.705-714
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• 2012

Precast reinforced concrete bridge columns with hollow rectangular section were tested under cyclic lateral load with constant axial force to investigate its seismic performance. After all the precast column segments were erected, longitudinal reinforcement was inserted in the sheath prefabricated in the segments, which were then mortar grouted. Main variables of the test series were column aspect ratio, longitudinal reinforcement ratio, amount of lateral reinforcement, and location of segment joints. The aspect ratios were 4.5 and 2.5, and the longitudinal steel ratios were 1.15% and 3.07%. The amount of lateral reinforcement were 95%, 55%, 50%, and 27% of the minimum amount for full ductility design requirements in the Korean Bridge Design Code. The locations of segment joints in plastic hinge region were 0.5 and 1.0 times of the section depth from the bottom column end. The test results of cracking and failure mode, axial-flexural strength, lateral load-displacement relationship, and displacement ductility are presented. Then, safety of the ductility demand based seismic design in the Korean Bridge Design Code is discussed. The column specimens showed larger ductility than expected, because buckling of longitudinal reinforcing bar was prevented due to confinement developed not only by transverse steel but also by sheath and infilling mortar.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.2
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• pp.123-130
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• 2016

With the development of fast construction mode in shipbuilding market, the demand on accuracy management of hull is becoming higher and higher in shipbuilding industry. In order to enhance production efficiency and reduce manufacturing cycle time in shipbuilding industry, it is important for shipyards to have the accuracy of ship components evaluated efficiently during the whole manufacturing cycle time. In accurate shipbuilding process, block accuracy is the key part, which has significant meaning in shortening the period of shipbuilding process, decreasing cost and improving the quality of ship. The key of block accuracy control is to create a integrate block accuracy controlling system, which makes great sense in implementing comprehensive accuracy controlling, increasing block accuracy, standardization of proceeding of accuracy controlling, realizing "zero-defect transferring" and advancing non-allowance shipbuilding. Generally, managers of accuracy control measure the vital points at section surface of block by using the heavy total station, which is inconvenient and time-consuming for measurement of vital points. In this paper, a new measurement method based on point clouds technique has been proposed. This method is to measure the 3D coordinates values of vital points at section surface of block by using 3D scanner, and then compare the measured point with design point based on ICP algorithm which has an allowable error check process that makes sure that whether or not the error between design point and measured point is within the margin of error.

• Journal of Acupuncture Research
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• v.19 no.4
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• pp.140-151
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• 2002

This study was carried to identify whether acupuncture at several meridian points can affect the human anesthesia or not through the analysis of serum intermediates, such as, melatonin, serotonin, TSH, cortisol in human serum. We investigated the effect of accupuncture on the change of serum intermediates which have frequently been made a subject of discussion owing to its hyponic and sedative properties in practice. The result obtained were as follow ; 1. Serum melatonin levels was hardly affected at 40 minutes after general acupuncture on Hab-Gog, Nae-Gwan, and the other meridian points as compared with that($5.64{\pm}1.02pg/ml$) of resting control group. But on day 1 after acupuncture, these tend to increase significantly ($7.95{\pm}2.05pg/ml$ to $8.21{\pm}1.57pg/ml$, p <0.05). On the other hand, control group under sleep showed the serum level of $7.39{\pm}1.03pg/ml$. Additional acupuncture at In-Dang induced the increased melatonin level, especially at 40minutes after acupuncture(p <0.05). 2. Serotonin level in resting control serum recorded $51.14{\pm}8.17{\mu}g/ml$. Acupuncture at determined meridian point intend to increase average level of serotonin, but not significant. However observation on day 1 after acupuncture at Hab-Gwan meridian point and under sleeping showed the significantly increased serotonin level, $74.05{\pm}35.83{\mu}g/ml$, $70.44{\pm}13.08{\mu}g/ml$, respectively. 3. TSH level in intact human serum recorded $0.85{\pm}0.24{\mu}IU/ml$. and the serum exposed to acupuncture showed the irregular pattern of TSH level in a mean range of $0.76{\pm}0.44{\mu}IU/ml$ to $1.06{\pm}0.38{\mu}IU/ml$, regardless of meridian point or time after acupuncture. 4. The values of serum cortisol in control group were $11.76{\pm}2.06{\mu}g/dl$ in resting, $7.51{\pm}2.85{\mu}/dl$ under sleep, respectively. The level of serum cortisol in 40minutes after acupuncture was markedly (p <0.05) reduced to the serum levels of $5.65{\pm}2.58{\mu}g/dl$ (Hab-Gog, Nae-Gwan), $7.58{\pm}3.21{\mu}g/dl$ (Gyo-Gam, Sin-Mun besides Hab-Gog, Nae-Gwan), $6.43{\pm}3.54{\mu}g/dl$ (In-Dang besides to Hab-Gog, Nae-Gwan), respectively, as compared with control, intending to increase a little on day 1 after acupuncture. From the above results, the analysis of serum intermediates suggest that acupunctuation at meridian points applied to at this study act upon the phase of light anaesthesia or hypnosis, at the same time affect pituitary-adrenal axis rather than hypothalamus-pituitary axis in the secretary system of hormone and also don't affect dorsal-raphe nucleus according to the observation of change transition in serum intermediates, such as TSH, serotonin, and cortisol.

• Journal of Korean Academy of Nursing
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• v.26 no.2
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• pp.483-496
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• 1996

The purpose of this study was to describe how Korean nurses overcome the language barrier while working in the U.S. hospital settings. Twelve Korean nurses living in New York metropolitan area were asked open-ended, descriptive questions to collect the data. The interviews were done in Korean. All interviews were audiotaped under the permission of the participants and were transcribed verbatim. The data were analyzed using grounded theory analysis. The research process consisted of two phases. In the first phase 8 Korean nurses were interviewed and analyzed. In the second phase, further data were collected to verify categories and working hypotheses that were emerged from the first phase. The results of this study show that all Korean nurses experienced severe psychological stress such as confusion, anxiety, frustration, loss of self-confidence, embarrassment, guilt, depression, anger, and fear. Among the mode of communication such as listening, speaking, leading, and writing, they had the most difficulty in speaking. Speaking ability was especially important for them because of the emphasis of individualism and self-defense in the U.S. Among the verbal communication modes, non-face-to-face communications such as phone conversation and body language were the most difficu1t for them to overcome. It took at least 2 years for the participants to initially overcome the language barrier in U.S. hospitals. After 2-5 years they began to feel comfortable even in non-face-to-face communication. They could actively search for the better place to work after 5 years. They finally felt comfortable in English and in their job almost after 10 years. The factors that influenced the English improvement were ‘the years of clinical experience in Korea’, ‘the decade they came to the U.S.’ ‘coming to U.S. alone or with other Korean nurses’, ‘racial homogeneity or heterogeneity of the working unit’, and ‘the degree of social support’. The strategies Korean nurses used to overcome the language barrier included depending on the written communication, using ‘nunchi’, working and studying hard, and establishing good interpersonal relationships with co-workers. They also employed assertive behavior of the U.S., such as using more explicit verbal language and employing smiles and eye contact with others during the conversation. The results of the study may help Korean nurses and nursing students who try to work in U.S. hospital settings by understanding problems other Korean nurses faced, factors that influenced their English improvement, and strategies they used. They may also help U.S. nurses and administrators in developing and implementing efficient programs for newly employed Korean nurses by understanding major problems and feelings the Korean nurses experienced and strategies they used to overcome the language barriers.

• Journal of the Korea Concrete Institute
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• v.16 no.5 s.83
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• pp.635-643
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• 2004

In this study, the tensile strength of 321 full-sized grout-filled splice steeve specimens were compared and analyzed in order to afford the data for a reasonable and economical design of this system. The experimental variables analyzed in this study were embedment length of reinforcing bars, compressive strength of grout, sleeve geometry, loading pattern and final failure mode of specimen. Following main conclusions are obtained : 1) The strength of grout-filled splice sleeve tends to be improved with increasing compressive strength of grout and embedment length of reinforcing bars. Specially this tendency appears apparent in specimens of bond failure rather than rebar failure. 2) The results of this study show that the sleeve geometry have influence on the bond strength of grout-filled splice sleeve. 3) The grout-filled splice sleeve of bond failure don't show the difference of tensile strength according to size of rebar. 4) It is verified that the tensile strength required in ACI and domestic code is retained either when the compressive strength of grout over 70 MPa is used with embedment length of reinforcing bars over 4.5d or when the compressive strength of grout over 80 MPa is used with embedment length of rebars over 3.9d. 5) It is verified that the tensile strength required in AIJ code is retained in case when the embedment length of reinforcing bars is 0.8 times the rebar diameter longer than in ACI code.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.6
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• pp.57-65
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• 2007

This paper presents the design of single phase PFC(Power Factor Correction) using a DSP(TMS320F2812). In order to realize the proposed boost PFC converter in average current mode control, the DSP requires the A/D sampling values for a line input voltage, a inductor current, and the output voltage of the converter. Because of a FET switching noise, these sampling values contain a high frequency noise and switching ripple. The solution of A/D sampling keeps away from the switching point. Because the PWM duty is changed from 5% to 95%, we can#t decide a fixed sampling time. In this paper, the three A/D converters of the DSP are started using the prediction algorithm for the FET ON/OFF time at every sampling cycle(40 KHz). Implemented A/D sampling algorithm with only one timer of the DSP is very simple and gives the autostart of these A/D converters. From the experimental result, it was shown that the power factor was about 0.99 at wide input voltage, and the output ripple voltage was smaller than 5 Vpp at 80 Vdc output. Finally the parameters and gains of PI controllers are controlled by serial communication with Windows Xp based PC. Also it was shown that the implemented PFC converter can achieve the feasibility and the usefulness.

• The Mathematical Education
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• v.56 no.3
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• pp.301-318
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• 2017

This paper explores students' question generation process and their study in small group discussion. The research is based on Anthropological Theory of the Didactic developed by Chevallard. He argues that the savior (knowledge) we are dealing with at school is based on a paradigm that we prevail over whether we 'learn' or 'study' socially. In other words, we haven't provided students with autonomous research and learning opportunities under 'the dominant paradigm of visiting works'. As an alternative, he suggests that we should move on to a new didactic paradigm for 'questioning the world a question', and proposes the Study and Research Courses (SRC) as its pedagogical structure. This study explores the SRC structure of small group activities in solving ill-structured problems. In order to explore the SRC structure generated in the small group discussion, one middle school teacher and 7 middle school students participated in this study. The students were divided into two groups with 4 students and 3 students. The teacher conducted the lesson with ill-structured problems provided by researchers. We collected students' presentation materials and classroom video records, and then analyzed based on SRC structure. As a result, we have identified that students were able to focus on the valuable information they needed to explore. We found that the nature of the questions generated by students focused on details more than the whole of the problem. In the SRC course, we also found pattern of a small group discussion. In other words, they generated questions relatively personally, but sought answer cooperatively. This study identified the possibility of SRC as a tool to provide a holistic learning mode of small group discussions in small class, which bring about future mathematics classrooms. This study is meaningful to investigate how students develop their own mathematical inquiry process through self-directed learning, learner-specific curriculum are emphasized and the paradigm shift is required.

• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.725-729
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• 2006

A method was developed for the determination of fructooligosaccharides and raffinose contents in infant formula. The samples were extracted and analyzed by liquid chromatography equipped with carbohydrate column and evaporative light scattering detector. The mobile phase used for the gradient mode was water-acetonitrile, at a flow rate of 1.0mL/min. The method showed a mean recovery of 95-99%, the relative standard deviation obtained in the precision study was 0.774-8.982%, the quantification and detection limits were 25-50mg/L.

• Archives of Plastic Surgery
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• v.37 no.5
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• pp.705-707
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• 2010

Purpose: Tuberculous lymphadenitis constitutes about 30% of all types of extrapulmonary tuberculosis. Cervical lymphadenitis is the commonest form (70%), followed by axillary and inguinal. But inguinal tuberculous lymphadenitis is rare form. Especially isolated inguinal tuberculous lymphadenitis was seldom reported. In Korea, that case was not reported. This case emphasizes the need for awareness of tuberculosis as a possible cause of isolated inguinal adenitis. Methods: We experienced one case of isolated inguinal tuberculous lymphadenitis. We analyzed clinical features, preoperative assessments and method of treatments. Results: A 37-year-old female patient presented with a painless swelling in the left inguinal region of 12 month's duration. There was no history of urethral discharge, dysuria, genital sores, unprotected sexual contacts or trauma. Examination revealed enlarged left inguinal lymph nodes, $2{\times}1\;cm$, non-tender and firm mass. The external iliac, popliteal, right inguinal and other groups of lymph nodes were normal. Serologic tests, urinary tests and chest radiologic test were normal. The excision of mass was performed under the general anesthesia. A excisional biopsy showed chronic granulomatous inflammation with caseous necrosis, consistent with tuberculosis. After excision, the primary repair was done and completely healed on postoperative 25 days. Conclusion: The isolated inguinal tuberculous lymphadenitis was rare form of inguinal suppurative mass. Although medical management is the principal mode of therapy of tuberculous adenitis and surgery is rarely necessary, we didn't consider the possibility of tuberculous lymphadenitis in our case. A high index of suspicion is essential for a diagnosis of isolated inguinal tuberculous lymphadenitis. Our case emphasizes this importance and illustrates the need for awareness of tuberculosis as a possible cause of isolated inguinal adenitis.