• 대한수학회지
• /
• 제46권5호
• /
• pp.979-995
• /
• 2009

As warped product manifolds provide an excellent setting to model space time near black holes or bodies with large gravitational field, the study of these manifolds assumes significance in general. B. Y. Chen [4] initiated the study of CR-warped product submanifolds in a Kaehler manifold. He obtained a characterization for a CR-submanifold to be locally a CR-warped product and an estimate for the squared norm of the second fundamental form of CR-warped products in a complex space form (cf [6]). In the present paper, we have obtained a necessary and sufficient conditions in terms of the canonical structures P and F on a CR-submanifold of a nearly Kaehler manifold under which the submanifold reduces to a locally CR-warped product submanifold. Moreover, an estimate for the second fundamental form of the submanifold in a generalized complex space is obtained and thus extend the results of Chen to a more general setting.

• 대한수학회지
• /
• 제58권1호
• /
• pp.219-236
• /
• 2021

Let �� be a weighted projective line defined over the algebraic closure $k={\bar{\mathbb{F}}}_q$ of the finite field ��q and σ be a weight permutation of ��. By folding the category coh-�� of coherent sheaves on �� in terms of the Frobenius twist functor induced by σ, we obtain an ��q-category, denoted by coh-(��, σ; q). We then prove that coh-(��, σ; q) is derived equivalent to the valued canonical algebra associated with (��, σ).

• 한국음향학회지
• /
• 제20권3호
• /
• pp.91-97
• /
• 2001

능동소나 시스템에서 표적신호의 근거리 정보가 중요해짐에 따라, 표적 음향산란 신호의 고유한 특성을 분석하기 위해 실험적인 방법과 시뮬레이션 기법이 사용된다. 본 논문에서는 표적신호 합성을 위해 축소표적 반향실험을 수행하였고. 자료의 분석 결과 축소표적의 음향산란은 거울면 반사의 영향이 큰 것으로 분석되어, 표적신호 합성에서 기하광학이론을 응용하였다. 복잡한 형태의 표적을 여러 표본형상으로 분리하고, 각 표본형상의 기여도를 신호의 위상과 강도를 줌으로써 계산하였으며, 표적신호 합성모델의 검증을 위해 실제 축소표적 실험 결과와 비교하였다.

• 영어영문학
• /
• 제55권5호
• /
• pp.821-841
• /
• 2009

This paper explores the ways to reshape humanistic values of the curriculum of the English department of Korean universities. The English curricula are usually composed of three fields of literary studies, general education, and English proficiency, whose conventional humanistic values have been currently dwindling. As for literary studies, teaching literature still hovers over the canonical works of past decades, not allowing students to access the canon with their own ideas and ending up with authoritative monologues. The general education field leans toward edited texts rather than authentic ones, which ignores a genuine path of communication between the author and its readers. Subjects for English proficiency such as "TOEIC" tend to be taught online with no teacher's presence for the nominal purpose of optimizing economic efficiency in teaching. All these testify to the attenuation of humanistic values in the curriculum, which motivates us to suggest some ways to reshape the values. Authoritative monologue in teaching literature can be shifted to the open-ended conversation by using role-play methods as well as accepting extra-canonical works into the curriculum. Authentic texts for general education prove to be preferred by students with the successful result of our experiment. Lastly, it is teacher's presence in the class that helps get higher achievement of "TOEIC" than some online classes. As suggested above, open-ended conversation, wider communication between author and readers, and human presence of the class will help reshape humanistic values in the English curriculum.

• Korean Chemical Engineering Research
• /
• 제47권6호
• /
• pp.747-754
• /
• 2009

본 연구에서는 $1,000^{\circ}C$에서 24시간 열처리된 활성탄에서 다이옥신과 유사구조를 갖는 o-DCB(ortho-dichlorobenzene)의 등온흡착식을 실험을 통하여 구하였고, 분자모사를 통하여 예측하였다. 실험으로 분석된 활성탄의 분자식 및 작용기 비율을 바탕으로 초기 활성탄 기본구조를 설계한 후, COMPASS(condensed-phase optimized molecular potentials for atomistic simulation studies) force field를 이용하여 이 구조를 최적화하였다. 최적화된 활성탄 분자구조에서 공극률, 비표면적, 및 입자밀도의 모사결과는 실험값과 비교되었고, 이들에 대한 실험과 모사결과의 오차는 각각 7.62, 3.79, 2.80%를 보여주었다. 통계 열역학적 방법인 GCMC(Grand Canonical Monte Carlo) 기법을 이용하여, 최적화된 활성탄 구조에서 온도에 따른 o-DCB의 등온흡착 상수값을 예측하였으며, 이 모사결과는 실험값과 비교될 때, 3% 이하의 오차를 보였다. o-DCB의 흡착특성을 바탕으로 확인되어진 활성탄 구조에서 다이옥신의 일종인 2,3,7,8-TCDD(tetrachlorodibenzo-p-dioxin) 등온흡착상수, 흡착열, 그리고 기공확산계수를 최종적으로 구함으로서, 실험적으로 구하기 힘든 맹독성 잔류성 유기물질의 흡착특성을 분자모사기법을 통하여 예측하였다.

• Journal of electromagnetic engineering and science
• /
• 제10권3호
• /
• pp.166-170
• /
• 2010

To numerically calculate electromagnetic scattering from the electrical-large three-dimensional(3D) objects, the high-frequency approaches have been usually applied, but the accuracy and feasibility of these geometrical and physical optics(GO-PO) approaches, to some extent, are remained to be improved. In this paper, a new framework is developed for calculation of the near-field scattering field of an electrical-large 3D target by using a multilevel fast multipole algorithm(MLFMA) and generation of radar images by using a fast back-projection(FBP) algorithm. The MPI(Message Passing Interface) parallel computing is carried out to multiply the calculation efficiency greatly. Finally, a simple example of perfectly electrical conducting(PEC) patch and a canonical case of Fighting Falcon F-16 are presented.

• 천문학회보
• /
• 제43권1호
• /
• pp.55.1-55.1
• /
• 2018

Studies on rotation-powered pulsars with strong surface magnetic field may help us clarify the unclear link between magnetars and canonical radio pulsars because the magnetar-like emission is expected to be observed. PSR J1119-6127 associated with SNR G292.2-0.5 has a high magnetic field of $4.1{\times}1013$ gauss, and a young characteristic age of ~1700 years can be served as the good candidate to compare with magnetars and rotation-powered pulsars. The glitch accompanied by the radiative changes detected in 2007 is the first case we observed for a rotationally powered radio pulsar. This pulsar experienced magnetar-like outbursts in mid. 2016, similar to the 2006 transition occurred on the other radio-quiet rotation-powered pulsar with strong surface magnetic field, PSR J1846-0258. In this talk, I'll report the investigation with X-ray and gamma-ray data of this magnetar-like pulsar. A sudden decrease in the gamma-ray emission at the GeV band was detected immediately after the X-ray outburst. Accompanying with the disappearance of the radio pulsation, the gamma-ray pulsation cannot be resolved as well after the outburst. We tried to derive the timing behavior and some intriguing features of this pulsar in this work corresponding to the outburst using the Swift data, NuSTAR and XMM observations.

• 통합자연과학논문집
• /
• 제12권4호
• /
• pp.133-141
• /
• 2019

Mesenchymal stem cells (MSCs) are known to differentiate into multiple lineages, making neurogenic differentiation an important target in the clinical field. In the present study, we induced the neurogenic differentiation of cells using histone deacetylase (HDAC) inhibitors and studied their mechanisms for further differentiation in vitro. We treated cells with the HDAC inhibitors, MS-275 and NaB; and found that the cells had neuron-like features such as distinct bipolar or multipolar morphologies with branched processes. The mRNA expressions encoding for NEFL, MAP2, TUJ1, OLIG2, and SYT was significantly increased following HDAC inhibitors treatment compared to without HDAC inhibitors; high protein levels of MAP2 and Tuj1 were detected by immunofluorescence staining. We examined the mechanisms of differentiation and found that the Wnt signaling pathway and downstream mitogen-activate protein kinase were involved in neurogenic differentiation of MSCs. Importantly, Wnt4, Wnt5a/b, and Wnt11 protein levels were highly increased after treatment with NaB; signals were activated through the regulation of Dvl2 and Dvl3. Interestingly, NaB treatment increased the levels of JNK and upregulated JNK phosphorylation. After MS-275 treatment, Wnt protein levels were decreased and GSK-3β was phosphorylated. In this cell, HDAC inhibitors controlled the non-canonical Wnt expression by activating JNK phosphorylation and the canonical Wnt signaling by targeting GSK-3β.

• Journal of the Korean Data and Information Science Society
• /
• 제21권6호
• /
• pp.1071-1079
• /
• 2010

10종경기 전 종목에 관한 효율적이고 포괄적인 동시훈련은 불가능하다는 Tidow (2000)의 지적처럼 힘, 민첩성, 속력, 지구력 및 개개인의 심리적 특성을 요구하는 10종경기에서 선수들이 가지고 있는 체력과 기술을 각 종목에 효율적으로 안배하여 활용할 수 있는 능력은 매우 중요하다. 본 연구에서는 1990년 이후 거행된 올림픽과 세계육상선수권대회에서의 10종경기 기록을 이용하여 세계적인 선수들은 경기운영을 어떻게 하는지 선도표, 대응분석, 정준상관분석 및 상관분석을 이용하여 살펴보았다. 그 결과 최상위권에 속하는 선수들은 스피드가 매우 뛰어나며 투척경기에도 강하나 지구력 경기에만 약점을 보였으며 경기력 패턴이 뚜렷하게 나타났다. 또한 상위권 선수들은 도약경기에 강세를 보이고 최하위권 선수들은 지구력 경기에 강점을 보였다.

• 한국식품과학회지
• /
• 제35권4호
• /
• pp.653-659
• /
• 2003

황색콩과 검은콩의 원산지를 판별하기 위하여 일반성분 및 20 MHz pulsed NMR을 이용하여 자기완화시간을 측정하였다. 일반성분으로는 황색콩은 조지방 함량 만이 원산지별 차이를 나타내었고, 검은콩의 경우에는 수분과 단백질 함량이 원산지별 차이를 보였다. 20 MHz pulsed NMR을 이용하여 자기완화시간 및 고형지방함량을 측정한 결과 황색콩은 고형지방함량과 $T_2-CPMG$ 측정시 원산지에 따라 유의적인 차이를 나타내었으며, 검은콩은 $T_1-SR$을 제외한 모든 측정항목에서 원산지별 차이를 나타내었다. 황색콩과 검은콩의 원산지 판별 분석시 일반성분만으로 정준판별분석을 시행한 결과 $70{\sim}91.7%$의 정확도를 나타내었으나, NMR 자기완화시간 및 고형지방함량을 이용한 경우 100%의 정확성으로 원산지를 판별해낼 수 있었다.