• Korean Journal of Mathematics
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• 제5권2호
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• pp.141-149
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• 1997

We investigate chnage of the tensor $U^{\nu}{_{\lambda}{\mu}}$ induced by the conformal change in 6-dimensional $g$-unified field theory. These topics will be studied for the second class with the second category in 6-dimensional case.

• 대한수학회보
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• 제38권1호
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• pp.197-203
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• 2001

We investigate change of the torsion tensor $S_\omega\mu^\nu$ induced by the conformal change in 7-dimensional g-unified field theory. These topics will be studied for the second class with the first category in 7-dimensional case.

• Korean Journal of Mathematics
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• 제7권2호
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• pp.199-205
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• 1999

We investigate change of the tensor $U^{\nu}_{{\lambda}{\mu}}$ induced by the conformal change in 5-dimensional $g$-unified field theory. These topics will be studied for the second class in 5-dimensional case.

• 전력전자학회논문지
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• 제4권1호
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• pp.99-104
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• 1999

최근 산업이 대규모화함에 따라 고압 전력 변환 장치의 필요성이 증가하고 있고, 이에 따라 전력용 반도체 소자의 직렬 구동이 많이 이용되고 있다. 소자의 직렬 구동은 소자간에 적절한 전압 분배가 이루어져 개별 소자에 정격이상의 과전압이 인가되는 것을 방지하는 것이 큰 관건이다. 또한 고전압 회로에서는 부유 인덕턴스에 의한 소자의 과전압도 방지하여야 한다. 본 논문에서는 직렬 연결된 IGBT의 턴-오프 과도상태시 컬렉터 전압 기울기 조절로 안정된 전압 분배와 과전압을 방지하는 새로운 게이트 구동기법을 제안한다. 제안하는 게이트 구동기법은 컬렉터 전압을 검출하여 능동적으로 게이트 신호를 제어함으로써 과전압을 제한한다. 새로운 IGBT 게이트 구동회로를 제작하고 직렬 연결된 IGBT 회로에 적용하여 게이트 구동기법의 타당성을 검증하였다.

• Earthquakes and Structures
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• 제19권5호
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• pp.315-329
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• 2020

Through bolt connections in Concrete Filled Steel Tubes (CFSTs) has been proved to be good in terms of seismic performance and constructability. Stiffened extended end plate connection with full through type bolt helps to avoid field weld altogether, and hence to improve the quality of joints. An experimental study was conducted on the hysteretic performance of square interior beam-column connections using flat extended end plates with through bolt. The study focuses on the effect of the bond between the tie rod and the core concrete on the cyclic performance of the joint. The study also quantifies how much the interior joint is getting strengthened due to the confinement effect induced by bi-directional bolting, which is widely used in 3D moment resisting frames. For a better understanding of the mechanism and for the prediction of shear capacity of the panel zone, a mathematical model was generated. The various parameters included in the model are the influence of axial load, amount of prestress induced by bolt tightening, anchorage, and the concrete strut action. The study investigates the strength, stiffness, ductility, and energy dissipation characteristics. The results indicate that the seismic resistance is at par with American Institute of Steel Construction (AISC) seismic recommendations. The bidirectional bolting and bond effect have got remarkable influence on the performance of joints.

• 한국균학회지
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• 제15권3호
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• pp.135-141
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• 1987

원형질체 융합에 의한 식용버섯의 유전육종연구는 종래의 전통적 육종방법인 균사융합으로는 해결할 수 없는 균주간의 불화합성 장벽을 능가하여 새로운 품중육성에 그 기대가 크다. 한국의 주요재배 버섯이며, 날로 세계의 재배면적이 증가하는 느타리버섯류의 유전육종을 위하여 몇가지 종간의 체세포 잡종의 선발과 이들의 유성에 대하여 조사한 결과는 다음과 같다. 1. 이 종간 원형질체 융합으로 체세포 잡종을 선발하였는데, 느타리+노랑느타리, 느타리+사철느타리, 느타리+여름느타리, 사철느타리+노랑느타리, 사철느타리+여름느타리 그리고 여름느타리+노랑느타리의 원형질체 융합율은 0.002-3.25%였으며, MCM과 MCM+benomyl에서 융합주의 균총분리가 일어나지 않았다. 2. 화합성 균주간에는 균사융합 및 원형질체 융합에 의하여 모두 균사체에 clamp connection을 형성하였으며, 자실체도 형성하였다. 그러나 불화합성 균주간에는 균사 및 원형질체 융합에 의하여 clamp connection을 확인할 수 없었으며, 자실체도 형성하지 않았다. 3. clamp connection이 없고 자실체도 형성하지 않는 원형질체 융합주의 임성을 유도하기 위하여, 이들 모균주와 균사융합한 결과 단핵균주와는 드물게 clamp connection을 형성하였으며, 이 핵균주와는 모두 clamp connetion을 형성하였다. 4. 불화합성 균주간의 원형질체 융합주는 새로운 불화합성을 형성하였는데, ASI 2-3+ASI 2-53의 P148은 ASI 2-3과 화합성인 ASI 2-1, ASI 2-2와 불화합성을 나타냈다. 또한 ASI 2-3+ASI 2-44의 P150은 ASI 2-3과 화합성인 ASI 2-1, ASI 2-2와 불화합성이었다.

• Journal of Korean Neurosurgical Society
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• 제46권1호
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• pp.1-4
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• 2009

Objective: To report an unsuspected adaptive plasticity of single upper motor neurons and of primary motor cortex found after microsurgical connection of the spinal cord with peripheral nerve via grafts in paraplegics and focussed discussion of the reviewed literature. Methods: The research aimed at making paraplegics walk again, after 20 years of experimental surgery in animals. Amongst other things, animal experiments demonstrated the alteration of the motor endplates receptors from cholinergic to glutamatergic induced by connection with upper motor neurons. The same paradigm was successfully performed in paraplegic humans. The nerve grafts were put into the ventral-lateral spinal tract randomly, with out possibility of choosing the axons coming from different areas of the motor cortex. Results: The patient became able to selectively activate the re-innervated muscles she wanted without concurrent activities of other muscles connected with the same cortical areas. Conclusion: Authors believe that unlike in nerve or tendon transfers, where the whole cortical area corresponding to the transfer changes its function a phenomenon that we call "brain plasticity by areas". in our paradigm due to the direct connection of upper motor neurons with different peripheral nerves and muscles via nerve grafts motor learning occurs based on adaptive neuronal plasticity so that simultaneous contractions of other muscles are prevented. We propose to call it adaptive functional "plasticity by single neurons". We speculate that this phenomenon is due to the simultaneous activation of neurons spread in different cortical areas for a given specific movement, whilst the other neurons of the same areas connected with peripheral nerves of different muscles are not activated at the same time. Why different neurons of the same area fire at different times according to different voluntary demands remains to be discovered. We are committed to solve this enigma hereafter.

• 한국균학회지
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• 제15권4호
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• pp.250-253
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• 1987

원형질체내에 외래유전물질 도입에 의한 균주 개발의 가능성 검토의 일환으로 사철느타리의 원형질체로부터 핵을 분리하여 느타리의 원형질체내로 전이하여 얻은 결과는 다음과 같았다. 1. 핵전이주는 크게 3가지 type으로 구분되었는데 type 1은 아주 빠른 균사생장과 clamp connection를 형성하지 않으며 CM+benomyl에서 균총분리가 나타남으로서 이질이배체로 사료되었다. type 2는 주된 핵전이주로서 모균주와 비슷하거나 다소 빠른 균사생장과 clamp connection을 지녀 자실체를 형성하였으며 heterokaryon으로서 원형질체 융합주와 유사하였다. 그러고 type 3은 핵 또는 염색체 단편의 전이로 clamp connection를 지니지 않고 아주 느리거나 MM에서 생육이 거의 불가능한 균주였다. 2. 핵전이주 및 모균주를 전기영동법으로 esterase 동위효소 pattern을 조사한 결과 핵전이주는 모균주와 구별되었는데 type 1인 이질이배체는 새로운 band를 나타내었으며, type 2와 type 3은 모균주들을 합한 것으로 보였다.

• 대기
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• 제32권3호
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• pp.223-233
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• 2022

Recent studies have shown that Madden-Julian Oscillation (MJO) is modulated by Quasi-Biennial Oscillation (QBO) during the boreal winter; MJO becomes more active and predictable during the easterly phase of QBO (EQBO) than the westerly phase (WQBO). Despite growing evidences, climate models fail to capture the QBO-MJO connection. One of the possible reasons is a weak static stability change in the upper troposphere and lower stratosphere (UTLS) by neglecting QBO-induced ozone change in the model. Here, we investigate the possible impact of the ozone-radiative feedback in the tropical UTLS on the QBO-MJO connection by integrating the Global Seasonal Forecasting System 5 (GloSea5) model. A set of experiments is conducted by prescribing either the climatological ozone or the observed ozone at a given year for the EQBO-MJO event in January 2006. The realistic ozone improves the temperature simulation in the UTLS. However, its impacts on the MJO are not evident. The MJO phase and amplitude do not change much when the ozone is prescribed with observation. While it may suggest that the ozone-radiative feedback plays a rather minor role in the QBO-MJO connection, it could also result from model biases in UTLS temperature and not-well organized MJO in the model.

• 대한치과보철학회지
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• 제42권4호
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• pp.356-372
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• 2004

Statement of problom: In the internal connection system the loading transfer mechanism within the inner surface of the implant and also the stress distribution occuring to the mandible can be changed according to the abutment form. Therefore it is thought to be imperative to study the difference of the stress distribution occuring at the mandible according to the abutment form. Purpose: The purpose of this study was to assess the loading distributing characteristics of 3 implant systems with internal connection under vertical and inclined loading using finite element analysis. Material and method: Three finite element models were designed according to the type of internal connection of ITI(model 1), Friadent(model 2), and Bicon(model 3) respectively. This study simulated loads of 200N in a vertical direction (A), a $15^{\circ}$ inward inclined direction (B), and a $30^{\circ}$ outward inclined direction (C). Result: The following results have been made based on this numeric simulations. 1. The greatest stress showed in the loading condition C of the inclined load with outside point from the centric cusp tip. 2. Without regard to the loading condition, the magnitudes of the stresses taken at the supporting bone, the implant fixture, and the abutment were greater in the order of model 2, model 1, and model 3. 3. Without regard to the loading condition, greater stress was concentrated at the cortical bone contacting the upper part of the implant fixture, and lower stress was taken at the cancellous bone. 4. The stress of the implant fixture was usually widely distributed along the inner surface of the implant fixture contacting the abutment post. 5. The stress distribution pattern of the abutment showed that the great stress was usually concentrated at the neck of the abutment and the abutment post, and the stress was also distributed toward the lower part of the abutment post in case of the loading condition B, C of the inclined load. 6. In case of the loading condition B, C of the inclined load, the maximum von Misess stress at the whole was taken at the implant fixture both in the model 1 and model 2, and at the abutment in the model 3. 7. The stress was inclined to be distributed from abutment post to fixture in case of the internal connection system. Conclusion: The internal connection system of the implant and the abutment connection methods, the stress-induced pattern at the supporting bone, the implant fixture, and the abutment according to the abutment connection form had differenence among them, and the stress distribution pattern usually had a widely distributed tendency along the inner surface of the implant fixture contacting the a butment post.