• 한국수학사학회지
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• 제28권5호
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• pp.207-231
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• 2015

We discuss several issues relating to the meaning of the terms and phrases in the first half of Chapter One fang tian 方田章 of ${\ll}$Jiuzhang suanshu九章算術${\gg}$. I understood those issues more clearly in the course of the translation of ${\ll}$Kujang sulhae 九章術解${\gg}$. Those are '今有' in the beginning of each problem, '積' and '冪' in the method of square field 方田術, '齊' in the method of reduction to a common denominator 齊同術, '經' and '有分者通之重有分者同而通之' in the method of dividing fraction 經分術, '實如法而一' in the calculation using the rods, '兩邪' in the method of trapezium field with a perpendicular side 邪田術. We may find out the value of ${\ll}$Kujang sulhae 九章術解${\gg}$ through our discussion.

• 한국수학교육학회지시리즈A:수학교육
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• 제46권3호
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• pp.245-261
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• 2007

This paper deals with the possible problems which may arise when students learn the names of elementary geometric figures in the languages of Korean, Chinese, English. The names of some simple geometric figures in these languages are analyzed, and a specially designed test was administered to some grade eight students from the three language groups to explore the possible influence of the characteristics of the languages on students' capability in identifying the figures, the way students define the figures, and students' understanding of the inclusive relationship among figures. It was found that the usage of the terms to describe geometric figures may indeed have affected students' understanding of the figures. The names of geometric figures borrowed from those of everyday life objects may cause students to fix on some attributes of the objects which may not be consistent with the definition of the figures. Even when the names of the geometric figures depict the features of the figures, the words used in the naming of the figures may still affect students' understanding of the inclusive relations. If there is discrepancy between the definition of a geometric figure and the features that the name depicts, it may affect students' understanding of the definition of the figure, and if there is inconsistency in the classification of figures, it may affect students' understanding of the inclusive relationship involving those figures. Some implications of the study are then discussed.

• 천문학회지
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• 제20권1호
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• pp.1-26
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• 1987

By inverting the brightness integral for the dust-scattered continuum, we have determined how the dust grains are distributed inside the Orion nebula. The scattering characteristics of the Orion dust at a given wavelength is kept constant within the nebula, and the geometry of the nebula is assumed to have a hemispherical shape. The resulting radial distance dependence of the distribution of dust number density, $N_d(r)$, shows that the dust grains are depleted at the central region of the Orion nebula and concentrated in the region $5'{\sim}6'$ away from the Trapezium stars. The scattering characteristics of the Orion dust are of moderately forward throwing nature, and the Orion dust has low values of albedo.

• 천문학회보
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• 제40권2호
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• pp.36.1-36.1
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• 2015

We present $5-14{\mu}m$ Infrared Spectrograph spectra of 14 T Tauri stars which show Polycyclic Aromatic Hydrocarbon (PAH) features and reside in 0.7 pc from ${\Theta}_1$ Ori C. The spectral types of nine out of 11 stars have spectral type information, with types ranging from K7-M5. These stars do not supply strong enough UV photons to excite PAH emission in their disks. Therefore, we consider the detection of PAH emission in disks around low mass stars illuminated by an external source of UV photons, namely, from Trapezium OB association, including ${\Theta}_1$ Ori C. The morphological features of PAH emission from most disks around K-M type host stars are unique, not belonging to any known classes of PAH features. We found that the PAH emission strengths decrease as the projected distance of the objects from ${\Theta}_1$ Ori C increase. We suggest future far-IR and submm/mm observations for better understanding of the characteristics and distribution of PAHs in these disks.

• 전력전자학회논문지
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• 제27권3호
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• pp.200-205
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• 2022

This paper presents an improved maximum power point tracking method that can fast track the global maximum power point (GMPP) for a photovoltaic system under partial shading conditions. The proposed method combines the advantages of the maximum power trapezium (MPT) method and the search-skip-judge method to minimize the tracking voltage intervals. Thus, the proposed method can quickly track the GMPP by skipping unnecessary tracking voltage intervals. The superiority of the proposed method is verified through simulation results in the MATLAB/Simulink and experimental real-time operation results with the hardware-in-the-loop simulation. The simulation and experimental results demonstrated that the proposed method has a faster tracking time than the MPT method under various partial shading conditions.

• 대한골관절종양학회지
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• 제13권2호
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• pp.124-129
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• 2007

활막 육종은 수부에서는 드물게 발생하며 광범위 절제술을 요한다. 수부의 광범위 절제술을 시행할 때는 충분한 절제연을 얻어야 하지만 기능적인 면을 고려한 재건술이 요구된다. 저자들은 타병원에서 불완전 병소내 절제술후 전원된, 46세 남자의 우측 수지 무지구근 부위 활막육종에 대해 대능형골 및 제1 중수지골을 포함한 광범위 절제술 후, 비골 이식술과 전외측 대퇴 피판 이식술을 시행하여 재건술을 시행하여 우수한 결과를 얻은 증례를 보고하고자 한다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.344-352
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• 2019

Marine production strings are continuously affected by unstable internal fluid during operation. In this paper, the structural governing equation for marine production string self-induced vibration is constructed. A finite element analysis model is established based on Euler-Bernoulli theory and solved by the Newmark method. Furthermore, based on reliability theory, a self-design procedure is developed to determine the operability envelope for marine production string self-induced vibration. Case studies show: the response frequency of the production strings is consistent with the excitation frequency under harmonic fluctuation and mainly determined by the first-order natural frequency under stochastic fluctuation. The operability envelope for marine production string self-induced vibration is a near symmetrical trapezium. With the increasing of natural gas output, the permissible fluctuation coefficient dramatically decreases. A reasonable centralizer spacing, increasing top tension, and controlling natural gas output are of great significance to the risk control in marine production string operation.

• Archives of Hand and Microsurgery
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• 제23권4호
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• pp.223-229
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• 2018

목적: 무지 수근중수 관절염(thumb carpometacarpal joint arthritis)에 대한 관절성형술로 대다각골을 제거한 후 중수골을 안정시키는 여러 방법이 소개되어 있다. 현수 봉합 관절성형술은 덜 침습적이면서 술식이 쉬운 장점이 있다. 본 연구는 무지 수근중수 관절염 환자에서 이 술식을 이용하여 수술한 결과를 알아보고자 한다. 방법: 무지 수근중수 관절염으로 진단받고 현수 봉합 관절성형술을 시행한 환자 12명을 대상으로 후향적으로 연구하였다. 시각통증척도, 수술만족도, DASH (disabilities of the arm, shoulder and hand) 점수를 조사하였고, 단순방사선 검사에서 대다각골 공간 비율을 계측하였다. 결과: 평균 추시 기간은 23개월이었다. 수술 전후 통증 점수는 7.0에서 2.9로 유의하게 감소하여 호전을 보였고 (p<0.05), 수술만족도는 평균 6.9였다. 그러나 수술 전후 DASH 점수는 유의한 차이가 없었다(p=0.06). 평균 대다각골 공간 비율은 수술 전 0.45, 수술 직후 0.33, 마지막 추시 시 0.23이었다. 결론: 현수 봉합 관절성형술은 수술 결과가 만족스럽고, 다른 술식과 비교하여 중수골 침강에 의한 대다각골 공간의 감소도 큰 차이가 없어 진행된 무지 수근중수 관절염 환자에서 유용하게 사용될 수 있을 것으로 생각한다.