• 대한기계학회논문집
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• 제16권5호
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• pp.1011-1018
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• 1992

A series of experiment has been performed on the spray characteristics in a cylindrical confined space with the injection pressure taken as a parameter. By using a single-hole patternator and the Malvern particle sizer, the spray mass flux, drop size and volume concentration distributions along the radial and axial directions were obtained ; the line-of- sight data by Malvern particle sizer have been converted to the ring-of-sight data by using the tomographical transformation techniqe. The experimental results show that, due to the restriction on the ambient gas entrainment by the wall boundary, the effective spray angle is increasing. The spray drops were measured to be smaller in the confined space because of a large number of floating small drops by recirculation of the gas phase and the breakup of large drops by the wall collision. Also the details on the flow behavior of the confined spray are discussed.

• Journal of Magnetics
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• 제18권3호
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• pp.255-259
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• 2013

In this paper a new coupling method for efficient and simple analysis of single phase induction motor is presented. The circuit representation of both the stator winding and each conducting rotor loop (composed of rotor bar and end ring segment) is used in conjunction with the distribution of magnetic flux linkage instead of inductance matrix. The flux linkage is calculated using air-gap flux density distributions driven by unit currents in the stator windings and rotor bars. The field distribution of one turn of a coil is calculated by FEM and the result is used to calculate total flux linkage by employing a coordinate transformation. The numerical results give good agreement with prior literature. The method is particularly effective in analyzing the effect of the number of rotor bars.

• Journal of Multimedia Information System
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• 제8권1호
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• pp.45-56
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• 2021

This document traces the new technologies development based on a deep classical Hill method improvement. Based on the chaos, this improvement begins with the 256 element body construction, which is to replace the classic ring used by all encryption systems. In order to facilitate the application of algebraic operators on the pixels, two substitution tables will be created, the first represents the discrete logarithm, while the second represents the discrete exponential. At the same time, a large invertible matrix whose structure will be explained in detail will be the subject of the advanced classical Hill technique improvement. To eliminate any linearity, this matrix will be accompanied by dynamic vectors to install an affine transformation. The simulation of a large number of images of different sizes and formats checked by our algorithm ensures the robustness of our method.

• East Asian mathematical journal
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• 제37권1호
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• pp.87-95
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• 2021

Let K be an imaginary quadratic field with ��K its ring of integers. For a positive integer N, let K(N) be the ray class field of K modulo N��K, and let ��N be the field of meromorphic modular functions of level N whose Fourier coefficients lie in the Nth cyclotomic field. For each h ∈ ��N, we construct a ray class invariant as its special value in terms of the extended form class group, and show that the invariant satisfies the natural transformation formula via the Artin map in the sense of Siegel and Stark. Finally, we establish an isomorphism between the extended form class group and Gal(K(N)/K) without any restriction on K.

• 한국수산과학회지
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• 제3권3호
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• pp.154-160
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• 1970

우리나라 서해안의 참조기를 대상으로 1967년 6월부터 1968년 5월 사이의 자료에서 체장, 체중 및 인문(鱗紋)조사를 실시하며 다음의 결과를 얻었다. 1. 윤문은 연 1회 형성되고, 형성 시기는 $4\~7$월로, Bae(1960)가 발표한 산란기와 일치되고 있다. 2. 윤군(輪群)별 각 윤경(輪徑)적 평균 성장률은 0.73이었다. 3. 체장(total length)과 인경(鱗徑)과의 관계는 직선 회귀로, 그 관계식은 다음과 같다. L=61.350R+50.184 4. 체중과 체장(total length)과의 관계는 지수 곡선으로 다음과 같다. $$W=4.298L^{3.227}\times10^{-3}$$ 5. Walford의 정차도에 의하여 산출된 이론적인 최대 체강은 346.9mm이었고, 그 관계식은 다음과 같다. $$L_{n+1}=0.6866L_n+10.8730$$ 6. 연령과 체장(total length)과의 관계를 von Bertalanffy의 성장 방정식에 적응시킨 결과 다음과 같았다. $$L_t=346.9(1-e^{-0.376(t+0.609)})$$

• 대한화학회지
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• 제36권2호
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• pp.301-304
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• 1992

에탄올성 사카르보닐철산염, $HFe(CO)_4^-$과 아디파알데히드를 조합하면 아미노기를 과수소아제핀고리로 선택적으로 전환을 하는데 매우 효과적이다. 페닐렌디아민은 상압의 일산화탄소, 상온, 및 철산염 존재하에서 아디파알데히드와 반응하여 대응하는 과수소아제핀을 보통의 수득율로 주었다. 이 반응에 철산염아디파알데히드-페닐렌디아민계에서 몰비가 1.0 : 1.0 : 1.0일 때는 한 개의 과수소아제핀고리를, 1.0 : 2.0 : 1.0의 경우에는 두 개의 과수소아제핀고리를 선택적으로 주었다.

• 청정기술
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• 제29권4호
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• pp.255-261
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• 2023

파워반도체는 전력의 변환, 변압, 분배 및 전력제어 등을 감당하는데 사용되는 반도체이다. 최근 세계적으로 고전압 파워반도체의 수요는 다양한 산업분야에 걸쳐 증가하고 있는 추세이며 해당 산업에서는 고전압 IGBT 부품의 최적화 연구가 절실한 상황이다. 고전압 IGBT개발을 위해서 wafer의 저항값 설정과 주요 단위공정의 최적화가 완성칩의 전기적특성에 큰 변수가 되며 높은 항복전압(breakdown voltage) 지지를 위한 공정 및 최적화 기술 확보가 중요하다. 식각공정은 포토리소그래피공정에서 마스크회로의 패턴을 wafer에 옮기고, 감광막의 하부에 있는 불필요한부분을 제거하는 공정이고, 이온주입공정은 반도체의 제조공정 중 열확산기술과 더불어 웨이퍼 기판내부로 불순물을 주입하여 일정한 전도성을 갖게 하는 과정이다. 본 연구에서는 IGBT의 3.3 kV 항복전압을 지지하는 ring 구조형성의 중요한 공정인 field ring 식각실험에서 건식식각과 습식식각을 조절해 4가지 조건으로 나누어 분석하고 항복전압확보를 위한 안정적인 바디junction 깊이형성을 최적화하기 위하여 TEG 설계를 기초로 field ring 이온주입공정을 4가지 조건으로 나누어 분석한 결과 식각공정에서 습식 식각 1스텝 방식이 공정 및 작업 효율성 측면에서 유리하며 링패턴 이온주입조건은 도핑농도 9.0E13과 에너지 120 keV로, p-이온주입 조건은 도핑농도 6.5E13과 에너지 80 keV로, p+ 이온주입 조건은 도핑농도 3.0E15와 에너지 160 keV로 최적화할 수 있었다.

• 대한화학회지
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• 제34권5호
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• pp.469-475
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• 1990

2,6-dichloroquinoxaline (13)과 m-chloroperbenzoic acid를 반응시켜 2,6-dichloroquinoxaline 4-oxide (14)를 합성하고, 이것과 pyrrolidine 혹은 indoline을 반응시켜 2-substituted 6-chloroquinoxaline 4-oxide류(15)를 합성하였다. 그리고 이들과 dimethyl acetylenedicarboxylate를 반응시키니 isoxazolo[2,3-a]quinoxaline류(16)와 pyrrolo[1,2-a]quinoxaline류 (17)가 선택적으로 합성되었다. 더욱이 pyrrolo[1,2-a]quinoxaline류 (17)는 isoxazolo[2,3-a]quinoxaline류 (16)의 고리변환에 의하여 생성된다는 것을 알았다.

• 원예과학기술지
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• 제29권5호
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• pp.467-473
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• 2011

Flavonoid are large group of the polyphenolic compounds which are distinguished by an aromatic or phenolic ring structure and the phenolic compounds are induced by microbial infection, ultraviolet radiation, temperature and chemical stress. They are known for their antioxidant activity, anti-allergic, anti-inflammatory, anti-microbial and anti-cancer activities. In this study, changes in flavonoid content were investigated using heterologous chalcone isomerase (CHI) expression system. Also, phenolic compounds level was measured to examine the relation between flavonoids and phenols contents. Explants of lettuce (Lactuca sativa L.) were transformed with Agrobacterium tumefaciens LBA 4404 strain containing pFLH-CHI (derived from pPZP2Ha3) vector constructed with CHI gene from Brassica rapa. The putative transgenic plants were confirmed by genomic DNA PCR analysis. Also the transcription levels of the gene were analyzed by semi-quantitative RT-PCR with gene specific primers. The total flavonoid contents were increased at $T_0$ and $T_1$ generations over 1.4 and 4.0 fold, respectively. Total phenol contents also increased at $T_1$ generation. These results indicate that CHI gene plays an important role to regulate the accumulation of flavonoids and its component changes.

• 한국운동역학회지
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• 제14권2호
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• pp.1-14
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• 2004

This study was intended to contribute to allowing athletes to raise a technical understanding of two motions of high difficulty such as the Swallow motion and the Nakayama motion and enhance their competitive power by analysing the kinematical factors required to link those two motions on the competitive scene on the rings for current national athletes. For this purpose, the game of the ring event was videotaped for male heavy gymnasts participating in the final elimination match of the 2004 Athens Olympic Games. This study attempted to select the performing motions of the final 1st-and 2nd-place athletes performing the linking motions from the Swallow motion and the Nakayama motion using the DLT(direct linear transformation) method. As a result, it arrived at the following conclusion : A1 properly performed the flexing and extending movements using the angular velocity of the segment and joint as the switching motion using the body at the time of linking the motion from the Swallow skill to the Nakayama skill. A2 was evaluated to perform the skill taking the form of depending on the force at the static state. Therefore, it is thought that A1 should take care of shaking at the time of using the elasticity of the body. It is thought that in case of A2 the proper use of the elasticity of the body take care of shaking at the switching motion while taking advantage of the force will contribute to his competitive power.