• Progress in Medical Physics
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• v.34 no.3
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• pp.33-39
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• 2023

Purpose: FLASH radiotherapy (RT) using ultra-high dose rate (>40 Gy/s) radiation is being studied worldwide. However, experimental studies such as preclinical studies using small animals are difficult to perform due to the limited availability of irradiation devices and methods for generating a FLASH beam. In this paper, we report the initial dosimetry results of a prototype electron linear accelerator (LINAC)-based irradiation system to perform ultra-high dose rate (UHDR) preclinical experiments. Methods: The present study used the prototype electron LINAC developed by the Research Center of Dongnam Institute of Radiological and Medical Sciences (DIRAMS) in Korea. We investigated the beam current dependence of the depth dose to determine the optimal beam current for preclinical experiments. The dose rate in the UHDR region was measured by film dosimetry. Results: Depth dose measurements showed that the optimal beam current for preclinical experiments was approximately 33 mA, corresponding to a mean energy of 4.4 MeV. Additionally, the average dose rates of 80.4 Gy/s and 162.0 Gy/s at a source-to-phantom surface distance of 30 cm were obtained at pulse repetition frequencies of 100 Hz and 200 Hz, respectively. The dose per pulse and instantaneous dose rate were estimated to be approximately 0.80 Gy and 3.8×10⁵ Gy/s, respectively. Conclusions: Film dosimetry verified the appropriate dose rates to perform FLASH RT preclinical studies using the developed electron-beam irradiator. However, further research on the development of innovative beam monitoring systems and stabilization of the accelerator beam is required.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7443-7450
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• 2014

To resolve shortcomings of high-rate anaerobic processes, such as high upward flow velocity, this study sought to improve the structure of the high-rate anaerobic reactor and evaluate its performance. The improved reactor was manufactured by adjusting the diameter and dividing the reactor into three parts. The evaluation of the structurally improved reactor revealed that the reactor could stabilize a single circuit, and prevent the accumulation of solid matter and leakage of microbes, thereby stabilize the microbes. In the process of anaerobic digestion, an increase in pH and alkalinity within the reactor was presumably attributed to bicarbonate created in the process of organic matter decomposition and due to the re-dissolution of some biogas. To maintain a high rate of organic matter removal, the reactor should be operated with more than 9 hrs of HRT and an organic matter load of under $10.kgTCODcr/m^3{\cdot}d$. The methane gas generated in the anaerobic digestion process showed a high content of 65~83 % at the organic matter load of over $7.7kgTCODcr/m^3{\cdot}d$. per removal of CODcr. The methane quantity was generated at $0.10{\sim}0.23m^3CH_4/kgCOD_{rem}$, showing that it was smaller than the theoretical methane generation amount (0.35) in the STP state. In the latter part of high-rate anaerobic process, an advanced treatment process was required to remove nitrogen.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.87-94
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• 2019

In the study, we show the annual average increasing rate of death bodies in the capital area was 2.1% while the annual average increasing rate of cremated bodies was 4.5%. As the annual average increasing rate of cremated bodies was about 2.1 times higher than the annual average increasing rate of death bodies, the increase rate of cremated bodies contrast to the increase rate of death bodies was relatively high. Also, the cremation rate of the capital area was increased by 9.5% from 80.3% in 2011 to 89.8% in 2017 while the increase rate of cremated bodies was 27.2%(N=21,694 people) from 79,866 people in 2011 to 101,560 people in 2017. Thus, the increase rate of cremated bodies contrast to the increase of cremation rate of the capital area was relatively very high. On the basis of 2017, the utilization rate of public cremation facilities in by capital area was 94.5% in Incheon Metropolitan City, 91.1% in Seoul Metropolitan City, and 20.9% in Gyeonggi-do, which showed huge differences in the utilization rate of public cremation facilities in the jurisdiction area of by capital area. Focusing on the actual state shown in the results of this study above, it would be necessary for Seoul Metropolitan City to carry forward a supply & demand policy of cremation facilities through the extension of cremation furnaces, for Gyeonggi-do to carry forward a policy to build the public cremation facilities focusing on the basic local government in the jurisdiction area, and for Incheon Metropolitan City to enforce the measures for the joint use of cremation facilities with the basic local government in the adjacent Gyeonggi-do jurisdiction area in order to improve the efficiency of the operation of cremation facilities.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.272-276
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• 2005

Candida tropicalis, an osmophilic strain isolated from honeycomb, produced xylitol at a maximal volumetric production rate of 3.5 g $l^{-1}$ $h^{-1}$ from an initial xylose concentration of 200 g $l^{-1}$. Even with a very high xylose concentration, e.g., 350 g $l^{-1}$, this strain produced xylitol at a moderate rate of 2.07 g $l^{-1}$ $h^{-1}$. In a fed-batch fermentation of xylose and glucose, 260 g $l^{-1}$ of xylose was added, and xylitol production was 234 g $l^{-1}$ for 48 h, corresponding to a rate of 4.88 g $l^{-1}$ $h^{-1}$. To increase the xylitol production rate, cells were recycled in a submerged membrane bioreactor with suction pressure and air sparging. In cell-recycle fermentation, the average concentration of xylitol produced per recycle round, total fermentation time, volumetric production rate, and product yield for ten rounds were 180 g $l^{-1}$, 195 h, 8.5 g $l^{-1}$ $h^{-1}$, and 85%, respectively. When cell-recycle fermentation was started with the cell mass contratrated two-fold after batch fermentation and was performed for ten recycle rounds, we achieved a very high production rate of 12 g $l^{-1}$ $h^{-1}$. The production rate and total amount of xylitol produced in cell-recycle fermentation were 3.4 and 11 times higher than in batch fermentation, respectively.

• Journal of Sasang Constitutional Medicine
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• v.18 no.3
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• pp.124-130
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• 2006

1. Objectives The purpose of this study was to investigate the concordance rate of the diagnostic results among Sasang Constitutional Medicine(SCM) specialists. 2. Methods We carried out two studies in order to investigate the concordance rate of the diagnostic results between SCM specialists. We calculated the kappa value for analyzing concordance rate(using the SPSS program). 1) Study A : We investigated 142 clients who had taken health examinations and diagnosis of Sasang constitution from March 9, 2005 to March 29, 2005 at a health examination center of Kyung-Hee medical center. Every SCM specialist diagnosed 142 clients directly. Each SCM specialist don’t know the other specialist’s diagnosis. 2) Study B : We investigated 176 clients who had taken health examinations and diagnosis of Sasang constitution from January 2005 to March 2005 at the department of Occupational and Environmental medicine of Kyung-Hee medical center. One SCM specialist diagnosed 176 clients directly and the other specialist knowing previous specialist’s diagnosis, diagnosed each person indirectly 3. Results 1) The concordance rate of the diagnostic results among SCM specialists in study A was relatively high(kappa value=0.700). 2) The concordance rate of the diagnostic results among SCM specialists in study B was high(kappa value=0.895). 4. Conclusions We can confirm the concordance rate of the diagnostic results among SCM specialists is relatively high.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.4
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• pp.319-337
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• 2004

The purpose of this study was to investigate the dietary life about Kimchi of the housewives. Self-administrated questionnaires were completed by 322 housewives in Wonju area. The results were as follows: In the point of housewives' domestic duties, over 50% of housewives took care of their domestic duties alone, and the rate who learned how to manage domestic duties from their mothers before marriage decreased as the age got younger. 77.6% of housewives responded that both man and woman could manage a dietary life at home in the future, and the rate of such response was higher as their educational careers were higher and they were younger. In the point of housewives' basic situation about Kimchi, the rate of housewives who knew how to prepare kimchi was high as they were older, and the holding rate of a refrigerator for Kimchi was high as much as 72.4%. In the point of preparation for Kimchi, the rate who made Kimchi by themselves was high, but the rate of preparing Kimchi by their parents for them was higher in the twenties. Frequency of making Kimchi, an amount or a kind of Kimchi were notably different according to housewives' age, a type of their family, the number of their family, and their having a job or not. Housewives' opinion of a market kimchi was that it was expensive, and not sanitary, and rate of purchasing Kimchi was also low. In the point of the prepartion method of Kimchi for the winter, the rate who gained Kimchi from their parents was higher as they lived in an apartment, and had a nuclear family, and had the lesser family members. In an amount of Kimchi prepared for the winter, 11∼22 heads were 23.9% and 21∼30 heads were 21.9%. In the point of the method preparing Kimchi in the future, 53.8% of housewives responded that they would make by themselves, and 28.0% answered they would prepare or purchase. 77.4% of housewives answered that they would teach how to make Kimchi to their children. In conclusion, in housewives of Wonju area, wanted to make Kimchi by themselves and wanted their children to learn how to make Kimchi.

• Journal of Korean Elementary Science Education
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• v.35 no.1
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• pp.1-12
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• 2016

The purpose of this study was to analyze question's patterns in elementary school science teacher's guide books of 5, 6th grade under the 2009 revised curriculum. A modified analysis framework based on Blosser's classified system was used to analyze 1,982 questions extracted from elementary science teacher's guide books by grade, by domain, and by teaching and learning stage. The findings of this study were as follows. First, of the 1,982 questions, the most prominent type of question was the propositional question and the following was the reproductive question. And, in comparing the question's patterns between 5, 6th grade, it was found that 6th grade had higher rate of close typed question, while 5th grade had higher rate of open typed question in its curriculum. Secondly, a comparative study about two domains, material and energy science domain and earth and life science domain, showed that the number of questions of each domain was not much different. However, it was found that propositional questions and applicable questions showed a higher rate in material and energy science domain, and anticipated questions and open typed questions including divergent and evaluative question showed higher rate in earth and life science domain. Moreover, although the total number of questions from integration and my fun research domain's contents was small, the rate of open typed questions was higher than any other domains. Finally, as a result of comparing and analyzing question's pattern in teaching and learning stages, the rate of reproductive question and anticipated questions was high at the stage of introduction. At the stage of development, the rate of propositional and reproductive questions was high. At the stage of conclusion, the rate of synthetic and applicable questions was high.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.545-548
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• 2004

The paper describes the design of high-speed, high-resolution Sample-and-Hold circuit which shows the conversion rate 80MHz and the power supply of 3.3v with 0.35um CMOS 2-poly 4-metal process for high-speed, high resolution Analog-to-Digital Converter. For improving Dynamic performance of Sample-and-Hold, Two Double bootstrap switch and high performance operational amplifier with gain booster, which are used. and For physical stability of Sample and Hold circuit, reduces excess voltage of gate in bootstrap switch. Simulation results using HSPICE shows the SFDR of 71dB, 75dB in conversion rate of 80MHz result for two inputs(0.5Vpp, 10MHz and 1Vpp, 10MHz) and the power dissipation of 48mW at single 3.3V supply voltage.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.266-272
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• 2002

High-speed machining is one of the most effective technology to improve productivity. Because of the high speed and hugh fried rate, high-speed machining can alive great advantages for the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining. Depth of cut, feed rate and spindle revolution are control factors. The effect of the control factors on machining accuracy is discussed fur the results of surface roughness and machining error in Z-direction of the high speed machining.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.393-396
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• 1997

High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages for the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining. Depth of cut and feed rate are control factors. The effect of the control factors on machining accuracy is investigated using two-way factorial design.