• Journal of the Korean Society of Radiology
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• v.12 no.6
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• pp.737-743
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• 2018

Patient exposure dose exposure test, which is one of the items of accuracy control of Computed Tomography, conducts measurements every year based on the installation and operation of special medical equipment under Article 38 of the Medical Law, And keep records. The CT-Dose phantom used for dosimetry can accurately measure doses, but has the disadvantage of high price. Therefore, through this research, the existing CT - Dose phantom was similarly manufactured with a 3D printer and compared with the existing phantom to examine the usefulness. In order to produce the same phantom as the conventional CT-Dose phantom, a 3D printer of the FFF method is used by using a PLA filament, and in order to calculate the CTDIw value, Ion chambers were inserted into the central part and the central part, and measurements were made ten times each. Measurement results The CT-Dose phantom was measured at $30.44{\pm}0.31mGy$ in the periphery, $29.55{\pm}0.34mGy$ CTDIw value was measured at $30.14{\pm}0.30mGy$ in the center, and the phantom fabricated using the 3D printer was measured at the periphery $30.59{\pm}0.18mGy$, the central part was $29.01{\pm}0.04mGy$, and the CTDIw value was measured at $30.06{\pm}0.13mGy$. Analysis using the Mann - Whiteney U-test of the SPSS statistical program showed that there was a statistically significant difference in the result values in the central part, but statistically significant differences were observed between the peripheral part and CTDIw results I did not show. In conclusion, even in the CT-Dose phantom made with a 3D printer, we showed dose measurement performance like existing CT-Dose phantom and confirmed the possibility of low-cost phantom production using 3D printer through this research did it.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.4
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• pp.330-336
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• 2018

El $Ni{\tilde{n}}o$ would cause extreme weather conditions, which would result in a negative impact on crop production. The objective of this study was to assess the impact of El $Ni{\tilde{n}}o$ on spring kimchi cabbabe production for the period from 1981- 2016 in South Korea. In this study, years with less than 1.0 Oceanic $Ni{\tilde{n}}o$ index were classified into non El $Ni{\tilde{n}}o$ years. The other years were classified as El $Ni{\tilde{n}}o$ years. The national average production of spring kimchi cabbage in El $Ni{\tilde{n}}o$ years ($3,800kg\;10a^{-1}$) tended to be less than that in non El $Ni{\tilde{n}}o$ years ($4,016kg\;10a^{-1}$). However, there was no significant differences (p = 0.078) in the production between these groups of years. The averaged production of spring kimchi cabbage of El $Ni{\tilde{n}}o$ end years ($3,707{\pm}331kg\;10a^{-1}$) was less than those of El $Ni{\tilde{n}}o$ start years and non El $Ni{\tilde{n}}o$ years by 186 and $309kg\;10a^{-1}$, respectively. Still, such difference was not significant statistically (p=0.127), either. In contrast, there were provinces where the production of spring kimchi cabbage had significant differences by El $Ni{\tilde{n}}o$ occurrence. For example, El $Ni{\tilde{n}}o$ end years had significantly less spring kimchi cabbage production than El $Ni{\tilde{n}}o$ start years and non El $Ni{\tilde{n}}o$ years in Gangwon (p=0.038) and Gyeongbuk (p=0.053) provinces. It appeared that differences in cabbage production resulted from short sunshine duration, which merits further analysis on the impact of extreme weather condtions during El $Ni{\tilde{n}}o$ years on crop production.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.193-200
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• 2019

The study was conducted surveying ultrasound room workers on hospital infection awareness in Daejeon and Choong-chunng region. The contamination of ultrasonic probes used in clinical trials was measured using ATP, and the results were verified after using 70% alcohol sterilization. It was measured on the group's general characteristics and the specific categories such as academic background, job type, having professional certificate and infection education. After the examination, the gel removal and method, disinfection status of the probe and variable correlation analysis were performed to analyze the recognition of the ultrasonic probe disinfection. After examination in ultrasound room, it was found that towels were used the most for cleaning, and the gel container was not replaced for more than three months. After 70% alcohol disinfection, ATP contamination was reduced from $1055.4{\pm}944.2$ to $133.5{\pm}93.2$ and the result was analyzed to be statistically significant.(${\rho}<0.01$) The found bacteria were CNS, Gram positive bacillus, and Micrococcus specs. In order to solve this problem, 70% alcohol sterilization was applied and the bacteria were not detected after the treatment. The research shows that regular training on infection control and efforts to prevent infection are necessary, and that 70% alcohol is effective in disinfect the bacteria. Therefore, the medical institution should provide active hospital infection control education to improve the awareness of hospital infection among workers and contribute to the prevention of patient infection. It is also understood that proper use of the results of this study will help prevent infection by means of ultrasonic probes.

• Journal of The Korean Association For Science Education
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• v.38 no.6
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• pp.885-899
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• 2018

As 'Science Inquiry Experiment' is newly introduced in the high school curriculum, where inquiry and experiment oriented education is insufficient, this study aims to analyze teacher's practice of 'Science Inquiry Experiment' in depth and identify contradictions during its process in the perspective of Cultural Historical Activity Theory. The research participant is teacher SHIN who is exclusively responsible for Science Inquiry Experiment. Starting with reflection on the practice of Science Inquiry Experiment class conducted in the first semester, interviews with participants, participatory observation and local materials were used during the 2nd semester's Science Inquiry Experiment class. A descriptive analysis of the teacher SHIN's practice of Science Inquiry Experiment was carried out and the contradictions in the activity system of the teacher SHIN were identified. The result reveals that in the overall practice of teaching Integrated Science and Science Inquiry Experiment, there were contradictions between teacher SHIN's recognition about cooperation(subject) and shared responsibility with other teachers(division of labor), and between teacher SHIN's recognition about the subjects(subject) and contrasting contents in teacher training courses(community). In the practice of teaching Science Inquiry Experiment, there were specific contradictions between teacher SHIN's recognition about the subject(subject) and time of job assignment(rule), between experimental activities(object) and experimental tools(tool), and between purpose of the subject(object) and directions about assessment(rule). These contradictions directly or indirectly influence the practice of teaching Science Inquiry Experiment. There needs to be support for constructing an activity system capable of supporting and promoting teachers' practice of Science Inquiry Experiment, and we made several suggestions to resolve the problems.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.1
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• pp.17-24
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• 2019

Purpose: The present study aims to assess the level of coherency and the accuracy of Point dose of the Isocenter of VERO, a linear accelerator developed for the purpose of the Stereotactic Body Radiation Therapy(SBRT). Materials and Method: The study was conducted randomly with 10 treatment plans among SBRT patients in Kyungpook National University Chilgok Hospital, using VERO, a linear accelerator between June and December, 2018. In order to assess the equipment's power stability level, we measured the output constancy by using PTW-LinaCheck, an output detector. We also attempted to measure the level of accuracy of the equipment's Laser, kV(Kilo Voltage) imaging System, and MV(Mega Voltage) Beam by using Tofu Phantom(BrainLab, Germany) to assess the accuracy level of geometrical Isocenter. We conducted a comparative analysis to assess the accuracy level of the dose by using an acrylic Phantom($30{\times}30{\times}20cm$), a calibrated ion chamber CC-01(IBA Dosimetry), and an Electrometer(IBA, Dosimetry). Results: The output uniformity of VERO was calculated to be 0.66 %. As for geometrical Isocenter accuracy, we analyzed the error values of ball Isocenter of inner Phantom, and the results showed a maximum of 0.4 mm, a minimum of 0.0 mm, and an average of 0.28 mm on X-axis, and a maximum of -0.4 mm, a minimum of 0.0 mm, and an average of -0.24 mm on Y-axis. A comparison and evaluation of the treatment plan dose with the actual measured dose resulted in a maximum of 0.97 % and a minimum of 0.08 %. Conclusion: The equipment's average output dose was calculated to be 0.66 %, meeting the ${\pm}3%$ tolerance, which was considered as a much uniform fashion. As for the accuracy assessment of the geometric Isocenter, the results met the recommended criteria of ${\pm}1mm$ tolerance, affirming a high level of reproducibility of the patient's posture. The difference between the treatment plan dose and the actual measurement dose was calculated to be 0.52 % on average, significantly less than the 3 % tolerance, confirming that it obtained predicted does. The current study suggested that VERO equipment is suitable for SBRT, and would result in notable therapeutic effect.

• Korean Journal of Heritage: History & Science
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• v.42 no.1
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• pp.72-87
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• 2009

This research is insect diversity analysis on the basis of survey results and bibliographies of Hongdo Island, Mts. Seoraksan, Hallasan, Daeamsan & Daeusan, Hyangnobong peak & Geonbongsan nature reserves and Dokdo Protected Natural Area among 10 designated nature reserves. The Mt. Hallasan nature reserve has 1,867 species in 22 orders and shows the highest species diversity. The species diversities of Mt. Seoraksan, Mt. Hyangnobong peak & Geonbongsan, Hongdo Island, Mt. Daeamsan & Daeusan, and Dokdo Protected Natural Area reveal 1,604 species in 19 orders, 704 species in 18 orders, 474 species in 19 orders, 468 species in 16 orders, and 114 species in 11 orders, respectively, in descending order. The order Lepidoptera shows as dominant taxa in Hongdo, Seoraksan, Hallasan, Hyangnobong peak & Geonbongsan, whereas the order Coleoptera as subdominant taxa in these areas. On the other hand, in Mt. Daeamsan & Daeusan, and Dokdo Protected Natural Area, the order Coleoptera appears as dominant taxa whereas the order Lepidoptera as subdominant taxa. The order Ephemeroptera has been shown the highest species diversity in Seoraksan which is reported to 25 species, Odonata in Hallasan to 28, Dermaptera in Seoraksan to 9, Orthoptera in Hallasan to 51, Hemiptera in Hallasan to 175, Homoptera in Seoraksan to 126, Hymenoptera in Hallasan to 183, and Diptera in Hallasan to 206. The species diversity is generally poor in Daeamsan & Daeusan, Hyangnobong peak & Geonbongsan, and Dokdo Protected Natural Area. Maybe this result is caused by the lack of various academic surveys compared to the other areas. It is needed to study systematic academic investigation on insect in the nature reserve areas in Korea, and to plan appropriate management and conservation on natural environment considering biodiversity of each nature reserve area.

• Korean Journal of Heritage: History & Science
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• v.46 no.3
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• pp.172-193
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• 2013

This study examines the production techniques and raw materials shown in the Korean dried-lacquer statues of Buddha through a careful observation of the Seated Dried-lacquer Bodhisattva Statue from the late Goryeo Dynasty which is currently possessed by Okura Museum of Art in Tokyo. As a method of study, the X-ray data and the results from a field survey were combined to analyze the production techniques and the characteristics of raw materials. Based on this analysis, a hypothesis was established on the production process and verified through a reenactment of the actual production process. Then, the characteristics of the techniques applied to each process and the raw materials were recorded in detail. Specifically, the dried lacquer techniques and the raw materials were estimated based on the results of naked-eye observation in comparison with the literature, especially the records of "Xiu Shi Lu" written by Huang Cheng of the Ming Dynasty which is considered as 'the textbook of lacquer techniques.' The raw materials used in the production of the traditional Korean lacquerware inlaid with mother-of-pearl were also referenced. As a result, it was found that the features of production techniques and the raw materials found in the Statue at Okura Museum of Art have many similarities with those of the Seated Dried-lacquer Statue of Lohan (Arhat) from Yuanfu 2 Nian Ming (1098) of the Song Dynasty which is currently at the Honolulu Museum of Art. In particular, the similarities include that the interior of the statue being vacant because the clay and the wood core were not replaced after being removed from the prototype, that the complete form was made in the clay forming stage to apply the lacquer with baste fiber fabric, that the clay and the wood core were removed through the bottom of the statue, and that the modeling stage was omitted and the final coat over the statue is very thin. Additionally, decorating with ornaments like Bobal and Youngrak made of plastic material was a technique widely popular in the Song Dynasty, suggesting that the Seated Dried-lacquer Bodhisattva Statue in Okura Museum of Art was greatly affected by the production techniques of the Dried-lacquer Buddha Statue from the Song Dynasty. There is no precise record on the origin and history of the Korean Dried-lacquer Buddha Statues and the number of existing works is also very limited. Even the records in "Xuanhe Fengshi Gaoli Tujing" that tells us about the origin of the Dried-lacquer Buddha Statue from the Yuan Feng Period (1078~1085) do not indicate the time of transmission. It is also difficult to trace the clear route of transmission of production techniques through existing Dried-lacquer Buddha Statues. Fortunately, this study could at least reveal that the existing Dried-lacquer Buddha Statues of Korea, including the one at Okura Museum of Art, have applied the production techniques rather differently from those used in the production of Japanese Datsukatsu Dried-lacquer Buddha Statues that have been known as the standard rule in making dried-lacquer statues of Buddha for a long time.

• Korean Journal of Heritage: History & Science
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• v.45 no.1
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• pp.122-147
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• 2012

The Four-guardian statues in Song-gwang buddhist temple, Suncheon, Korea, have been remade in AD 1628 and have been repaired and repainted over several times since then. Therefore, the study of the pigments applied on the statues can provide good chance for investigation about pigments used in the late Chosun Period. Pigments on fragments from Gwang-mok(Virupaksha), one of the Four-guardian statues, have been analyzed by optical microscope, SEM-EDX and XRD in order to identify the components and compounds. Six types of materials were found from the fragments, which are soil layer with brown clay band, soil layer containing a lot of fibers, Korean paper with loose texture, Korean paper with dense texture, silk, and hemp textile. Presumably, the soil layer which have brown clay band is basis layer and the other layers are repaired layers. From comparative study for the components of the pigments, applied on upper and lower parts of the repaired layers, we have concluded that those repaired layers had been applied on the statue by the following order; basis layer ${\rightarrow}$ Korean paper with loose texture ${\rightarrow}$ soil containing a lot of fibers ${\rightarrow}$ silk ${\rightarrow}$ hemp textile and Korean paper with dense texture. In addition, the years that those materials were applied on the statue have been estimated as 1720~1891, 1926, 1946 and 1976, respectively. The distinct features of each age are as the following; lead white and copper chloride hydroxide are major white and green pigments before 1891, zinc white, barium white, emerald green, and ultramarine blue appear after 1926 and titanium white uprises around 1976. Our result presented here, study on pigments applied on traditional statues over several different periods, will provide good database for future study on pigments used for traditional painting in Buddist temples and Dancheong.

• Journal of Energy Engineering
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• v.28 no.2
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• pp.18-35
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• 2019

The Korea District Heating Corporation operates a gas engine generator with a capacity of $4500m^3 /day$ of biogas generated from the sewage treatment plant of the Nanji Water Recycling Center and 1,500 kW. However, the actual operation experience of the biogas power plant is insufficient, and due to lack of accumulated technology and know-how, frequent breakdown and stoppage of the gas engine causes a lot of economic loss. Therefore, it is necessary to prepare technical fundamental measures for stable operation of the power plant In this study, a series of process problems of the gas engine plant using the biogas generated in the sewage treatment plant of the Nanji Water Recovery Center were identified and the optimization of the actual operation was made by minimizing the problems in each step. In order to purify the gas, which is the main cause of the failure stop, the conditions for establishing the quality standard of the adsorption capacity of the activated carbon were established through the analysis of the components and the adsorption test for the active carbon being used at present. In addition, the system was applied to actual operation by applying standards for replacement cycle of activated carbon to minimize impurities, strengthening measurement period of hydrogen sulfide, localization of activated carbon, and strengthening and improving the operation standards of the plant. As a result, the operating performance of gas engine # 1 was increased by 530% and the operation of the second engine was increased by 250%. In addition, improvement of vent line equipment has reduced work process and increased normal operation time and operation rate. In terms of economic efficiency, it also showed a sales increase of KRW 77,000 / year. By applying the strengthening and improvement measures of operating standards, it is possible to reduce the stoppage of the biogas plant, increase the utilization rate, It is judged to be an operational plan.

• Korean Journal of Heritage: History & Science
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• v.42 no.2
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• pp.4-39
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• 2009

The foundations of ancient wooden pagoda consist of the stylobate soil, exteriors, stairways and etc. The factors were different according to the time, region and the architects. As a result of many archaeological researches, we have the data of horizontal gutters as a part of the foundations of ancient wooden pagodas in Gogureyo, China, Japan. But so far archaeological researches have not revealed such data in Baekje and Silla~Unified Silla period wooden pagodas. In genarally, the eaves must protrude as much as the outer line of the foundation to protect its upper side from rain. The purpose of the aforementioned horizontal gutter was to protect the foundations of ancient wooden pagodas. In this article, we call this horizontal gutter the Naksubaji. After researching many archaeological findings of ancient wooden pagodas of China, Korea and Japan from 5th century to 7th century, it is suggested that the Naksubaji was installed to wooden pagodas of Baekje period in 6th century and Silla~Unified Silla periods in 7th century. In wooden pagodas of Baekje period in 6th century, Naksubajis were found in wooden pagodas of Gunsurisaji temple site, Neungsanrisaji temple site, Wangheungsaji temple site. Especially in case of the Wangheungsaji temple site, presumed line to make stylobate of wooden pagoda in Baekje period was confirmed by archaeological research and this case is similar to the early period wooden pagodas in Japan. Goryeocheok(ruler used in the Three Kingdoms) was used to construct wooden pagodas. According to the restoration plan of wooden pagodas to verify the protrusion of eaves, the ratio of the length of the foundation:the length of 1st storied building:the length of the center:the length of the corner was 4.9:2.7:1:0.9 between Gunsurisaji temple site pagoda and Wangheungsaji temple site pagoda. Also I found tne same length of tne 1st storied building between Gunsurisaji temple site pagoda and Wangheungsaji temple site pagoda. Therefore the exact scales and planning were adapted to the establishment of wooden pagodas in 6th century in Baekje period. But the Naksubaji was not producted after 6th century in Baekje period. Because the big wooden pagoda had been appeared, they were needed other style of the foundation. In wooden pagodas which were made in Silla~Unified Silla periods in 7th century, I found the Naksubaji in wooden pagodas in Youngmyosajl temple site, Hwangnyongsaji temple site, Sacheonwangsa temple site. The line of stone in Youngmyosajl temple site, the 2nd line expressed the area of pagoda, the relative analysis of the lower foundation between Neungsanrisaji temple site pagoda and Sacheonwangsa temple site pagoda were examined the Naksubaji. In Silla~Unified Silla periods, the establishment of wooden pagodas was started at 7th century. So they had the exactly details of wooden pagoda, but we had no data of the Naksubaji after the time made Sacheonwangsa temple site.