• Nuclear Engineering and Technology
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• v.5 no.2
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• pp.115-131
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• 1973

L.S. Pontryagin's maximum principle is applied to the minimum critical mass problem without any restriction on the ranges of uranium enrichment. For the analysis, two group diffusion equation is adopted for a cylindrical reactor neglecting the vertical axis consideration. The result shows that the three-zoned reactor turns out to be most optimal: the inner and outer zones with the minimum enrichment ; whereas the middle 3one with the maximum enrichment. With the given three-zoned reactor, critical condition is derived, which leads to the calculation of the determinant. By finding the roots of the determinant the numerical calculation of the minimum critical mass is carried out for the case of Kori reactor geometry changing the minimum or the maximum enrichment. It is found from many computed values that the least possible critical mass turns out to be the case of 1.2% maximum enrichment for the middle zone and 0.65% minimum enrichment for the inner and out zones.

• Communications of Mathematical Education
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• v.22 no.1
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• pp.27-39
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• 2008

In this paper we study triangle's properties related with angle bisectors, perpendiculars, circumcenter using the principle of the lever. We analyze proof method using the principle of the lever, and describe how to investigate intersection of segments, how to prove equalities and inequalities using the principle of the lever in triangle.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.2
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• pp.242-250
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• 1999

This paper presents an estimation scheme of the external torque applied on the motor by using measured motor input current when the IPM(Interior Permanent Magnet) rotor type BLDC motor operates with constant speed. In general, the BLDC motor is controlled by vector control method. If it could be operated at over critical speed, the control scheme must be modified to flux-weakening control method. The external torque applied on the motor using flux-weakening control method could not be calculated by conventional torque equation because the demagnetizing current Id exists in the motor input current. In this paper, the commonly used flux-weakening control method is studied and the modified torque estimation scheme is suggested. The estimation scheme has been verified by the simulations and experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.127-134
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• 1997

Abstract: A technique to analyze the vibrations of internally fluid-filled, semi-infinite cylindrical shell which has strength members embedded in the shell wall under the axial static tension conditon is presented by using the characteristic wave propagation theory based on the transfer matrix calculated from the finite element matrices of a short module section, with spatial Laplace Tranform technique, and is verified by comparison with the measured results of the test performed on a real module model, and the effects of the embedded strength members on the vibrational response is calculated and discussed.

• The Journal of Korean Philosophical History
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• no.38
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• pp.63-96
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• 2013

$L{\ddot{u}}Zuqian$(呂祖謙) was one of the famous philosophers during the Southern Song period, and is called one of DongNamSanXian(東南三賢) together with ZhuXi(朱熹) and ZhangShi(張?). With his profound knowledge transmitted and uphold by JiaXue(家學), $L{\ddot{u}}Zuqian$(呂祖謙) established his learning system, interacting with scholars of those days. Principally, $L{\ddot{u}}Zuqian$(呂祖謙)'s XinLun(心論) was based on Mengzi(孟子)' theory of LiangXin(良心) and BenXin(本心). $L{\ddot{u}}Zuqian$(呂祖謙) explained the meaning of such a conscience through ChuXin(初心) and Inner NeiXin(內心). According to $L{\ddot{u}}Zuqian$(呂祖謙), ChuXin(初心) arouses when one encounters external things, and this one's intention enables us to make the right judgments over the outside objects. NeiXin(內心) means LiangXin(良心) and BenXin(本心) that recovered the ability of moral awareness. The important significances of $L{\ddot{u}}Zuqian$(呂祖謙)'s XinLun(心論) are XinWai WuDao(心外無道), and XinWaiWuTian(心外無天). Through these, $L{\ddot{u}}Zuqian$(呂祖謙) emphasized that Tian(天), Dao(道), and Li(理) are one. $L{\ddot{u}}Zuqian$(呂祖謙) arranged a meeting of EHuSi(鵝湖寺), and exerted efforts to negotiate the academic differences between ZhuXi(朱熹) and LuJiuyuan(陸九淵). However, compared with LuJiuyuan(陸九淵) who asserted FaMingBenXin(發明本心), $L{\ddot{u}}Zuqian$(呂祖謙) put the emphasis on DaoWenXue(道問學) with self-awareness of conscience. Meanwhile, $L{\ddot{u}}Zuqian$(呂祖謙) valued much of Jing(敬) like ZhuXi(朱熹). But, to $L{\ddot{u}}Zuqian$(呂祖謙), Jing(敬) meant WuJianDuan(無間斷) of ChunYiBuZa(純一不雜) DaoDeXin(道德心), and implied the same as Cheng(誠). $L{\ddot{u}}Zuqian$(呂祖謙) stressed the reading and pursuit of study, however, he also asserted that Li(理) could be understood and realized through self-awareness of one's mind and its reflection, and working without interruption. $L{\ddot{u}}Zuqian$(呂祖謙)'s academic tradition of the XinXueDe XueFeng(心學的 學風), which reveals through compromise and confrontation with ZhuXi(朱熹), can be said that it will have a significant meaning of idealism of dispute in the Southern Song period.

• Journal of the Korean School Mathematics Society
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• v.12 no.3
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• pp.171-188
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• 2009

This study was designed for the purpose of identifying the influences of improved teaching method which constructed at the base of results of survey for finding present teaching-learning method of incenter and circumcenter of triangle. For this, we surveyed the students' understanding and math teachers' teaching method of incenter and circumcenter of triangle. Then, we designed alternative teaching method which innovated the problems from the resultic approaches of Incenter and circumcenter of triangle. And then, we taught students through new method and analyzed the influences of it to students.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.823-830
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• 2010

This paper deals with a coaxial-to-waveguide transition generating circularly polarized wave to be connected with horn antennas. By combining vertical coaxial fed structure, back-short and the polarization twisting structure, the circular polarization is successfully generated in the waveguide. The designed and implemented transition shows that the present structure can significantly reduce the size of the antenna part at X-band.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.11a
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• pp.71-79
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• 2002

Nuclear design characteristics of duplex burnable poison rod were evaluated based on 24 month cycle fuel for Korean Standard Nuclear Plant. A fuel assembly with duplex burnable poison rod was designed for an equivalent assembly to 16 gadolinia BPs. Duplex BP is composed of inner region of natural U-12wt%Gd$_2$O$_3$ and outer shell of 4.95wt%UO$_2$-2wt%Er$_2$O$_3$. In order to compare this duplex option, assemblies with 140 erbia pins were designed as an alternative option. The variation of k-infinitive, rod worth, pin peaking and MTC were compared. Duplex BP had the better neutronic performance than gadolinia BP in all parameters. However, Duplex BP was worse than erbia BP in the aspect of safety.

• Korean Journal of Medicinal Crop Science
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• v.7 no.3
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• pp.172-176
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• 1999

The saponins are considered the main effective components in Platycodon grandiflorum (Jacq.) A. DC.. In order to obtain the basic information for producing the high quality medicinal plant and processing, the crude saponin contents were analyzed with platycodi radix, the root of Platycodon grandiflorum by different cultivating years, parts, harvesting times and drying methods. The crude saponin contents were decreased by increasing cultivating years. The crude saponin contents were 2.74% in tail of root and 1.65 % in head of root, respectively. Besides, the contents of the crude saponin in cortex were 1.8 times more than that in core of root. The crude saponin contents in different harvesting times were 2.82% and 2.74% at March 10 and December 10, showing higher than that being harvested at June 10 and September 10. The crude saponin contents among drying methods were not significantly different at 5% level DMRT, but the hot air drying after steam showed the least crude saponin.

• Journal of the Korea Convergence Society
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• v.11 no.2
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• pp.127-137
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• 2020

This study is aimed to point out the direction for more reasonable and effective application of future digital technology in the exhibition. It's also to improve the satisfaction of visitors' overall experience through inspecting the special exhibition using digital technology in the national central museum in 2019. The relationship of visitors' expectations, experience and satisfaction are analyzed through literature investigation. Hence, four dimensions of digital experience were summarized on this basis, the content of the questionnaire was set through this research. The satisfaction of visitors to the digital technology experience was evaluated and the key contents needing to be improved were found through Importance-Performance Analysis (IPA). According to the IPA analysis, the content located in quadrant IV is analyzed emphatically, and improvement suggestions are put forward from macro-level, micro-level and viewer's inner levels. The results can be used as a reference for improving the feasibility of the current problem. In order to ensure the forward-looking and timeliness of this field, continuous research will be conducted according to the changes and developments.