• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.6
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• pp.447-454
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• 2017

A three-dimensional two-phase large eddy simulation(LES) has been conducted to investigate the breakup and atomization of liquid jets such as a diesel jet in parallel flow and water jet in cross flow. Gas-liquid two-phase flow was solved by a combined model of Eulerian for gas flow and Lagrangian for a liquid jet. Two stochastic breakup models were implemented to simulate the liquid column and droplet breakup process. The penetration depth and SMD(Sauter Mean Diameter) were analyzed, which was comparable with the experimental data.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.16 no.2
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• pp.173-182
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• 2005

This review is a clinical and research update of recent literature related to childhood onset schizophrenia (with an onset of psychosis by age 12). Childhood onset schizophrenia(COS) is a rare disorder, but that may represent a more homogeneous patient population in which to search for risk or etiologic factors of schizophrenia. These overview data show that COS shares the same clinical and neurobiological features as later onset forms of the disorder. Compared with later onset schizophrenia, however, this subgroup of patients appear to have more severe premorbid neurodevelopmental abnormalities, more cytogenic abnormalies, poor outcome, and potentially greater family histories of schizophrenia and associated spectrum disorders. Future studies of this subgroup may provide important clues as to the genetic basis for schizophrenia and how gene products influence certain feature of the disease, such as age of onset and mode of inheritance.

• The Korean Journal of Mycology
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• v.24 no.1 s.76
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• pp.1-7
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• 1996

Premitotic, mitotic and postmitotic nuclei in the dikaryotic somatic hyphae of Pleurotus ostreatus, the oyster mushroom fungus were ultrastucturally examined using chemical fixation and freeze-substitution process, and the behaviors of astral microtubules associated with these nuclei were closely analyzed. Electron microscopic examinations revealed that astral microtubules are significantly abundant when the nuclei are in the stage of migration and at the stage of migration, the separation of spindle pole body occurs. Such an abundancy of astral microtubules in premitotic migrating nuclei is well contrasted with mitotic and postmitotic nuclei with much fewer astral microtubules and it should be noted that neither of these latter classes of nuclei exhibits the separation of the spindle pole body. It is remarkable that the postmitotic nuclei that are believed to migrate actively are associated with the astral microtubules that are less in numbers and length. During all the stages of nuclear division, astral microtubules are invariably radiating from the spindle pole bodies and nucleolus remains within the nuclear envelope of dividing nuclei throughout the division. The functions of astral microtubules developed during the nuclear division as well as the nuclear migration and separation of the spindle pole body were closely examined.

• Korean Journal of Cognitive Science
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• v.20 no.1
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• pp.1-28
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• 2009

The expression KES, one of the most commonly used words in the Korean language, has various usages. This expression is also used to express English-like cleft constructions. Korean seems to employ at least three different types of cleft constructions: predicational, identificational, and eventual. The paper tries to provide a constraint-based analysis of these three types of Korean cleft constructions and implement the analysis in the LKB(Linguistic Knowledge Building) system to check the feasibility of the analysis. In particular, the paper shows how a typed feature structure grammar, couched upon HPSG, can provide a robust basis for parsing Korean cleft constructions.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.2
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• pp.1-9
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• 2010

LES(Large eddy simulation) of breakup and droplet atomization of a liquid jet into cross turbulent flow was performed. Two phase flow of gas and liquid phases were modeled by the mixed numerical scheme of both Eulerian and Lagrangian methods for gas and liquid droplet respectively. The breakup process of a liquid column and droplets was observed by implementing the blob-KH wave breakup model. The penetration depth into cross flow was comparable with experimental data for several variants of the liquid-gas momentum flux ratio by varying liquid injection velocity. SMD(Sauter Mean Diameter) distribution downstream of jet was analyzed.

• Korean Journal of Plant Tissue Culture
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• v.22 no.6
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• pp.339-343
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• 1995

This study was performed to investigate the effect of iron ion on the mesophyll protoplast culture of Arabidopsis thaliana. Mesophyll protoplasts were isolated and cultured in a modified IMH medium supplemented with various concentrations of Fe-EDTA. Relatively low concentration of Fe-EDTA (<0.02 mM) induced the low level (4.8%) of cell division. In addition the cell division and microcallus growth were dose-dependently stimulated by 0 to 1 mM of Fe-EDTA. In 0.5 to 1 mM concentration range of Fe-EDTA, microcolonies were readily formed and the plating deficiency (8.5%) also showed maximal rate. However more than 1 mM of Fe-EDTA inhibited the initial growth of protoplase. The overall results suggest that Fe2+ion concentration plays an important role at the early developmental stage of protoplast regeneration.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.12
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• pp.1489-1495
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• 2013

High-pressure flows are ubiquitous in many industrial fields. A representative application is fuel injection using a common-rail control system in diesel engines, where the injection pressure in the injector exceeds 1000 bar. In high-speed injection, the fluid injected through the nozzle undergoes breakup owing to the interaction with the ambient gas. The breakup process influences mixture formation, which in turn influences combustion in diesel engines. Therefore, it is very important to analyze the breakup process of fuel spray. The Reitz and Diwakar model and cascade atomization and breakup (CAB) model were used in this study as sub-models for the numerical analysis of the breakup process of fuel spray. This study aims to precisely analyze the breakup process of spray and to investigate the breakup frequency of the injected fuel. Consequently, it proposes a suitable sub-model for analyzing the breakup process of a diesel spray by using CFX, a commercial CFD program.

• The Zoological Society Korea : Newsletter
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• v.18 no.1
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• pp.10-15
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• 2001

사람의 체세포가 분열수명에 한계가 있다는 것은 1960년대 초기에 보고되었으며 이것은 artifact가 아니며 세포자신이 가지는 프로그램에 의한 것임이 보고된 것은 최근의 일이다. 그러나 이 프로그램 안에 체세포가 실지로 증식을 정지하는 시기, 모든 세포노화의 타이밍이 어떻게 설정되는가\ulcorner 에 대해서는 아직 알 수 없다. 한편 노화세포가 왜 증식할 수 없는가\ulcorner 에 대해서는 세포주기를 조절하는 유전자에 관한 최근의 연구에 의해 상당부분 밝혀졌다. 또한 분열회수를 인식하는 분열시계의 진행은 세포증식을 억제하는 유전자의 발현을 촉진하여 증식을 정지시킨다. 분열시계를 정지시킨 세포는 기본적으로 무한히 분열하는 것이 가능하다. 분열시계를 정지시키는 주역은 telomerase이다. 정상 세포에서는 생식소(生殖巢)에 존재한다. 대부분의 정상체세포, 세포조직에는 없으나 대부분의 암에서 존재한다. 본 논단에서는 전반부에 노화를 후반부에 암에 관해서 분자세포생물학 차원에서 최근 연구성과를 중심으로 살펴보고자 한다.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.11 no.2
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• pp.262-281
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• 2000

We focused on the peer relationship of adolescent patients with schizophrenia, which usually occurs around puberty. Reviewing cases with schizophrenia and the literature extensively, we had come to the conclusion as follows；1) the most robust predictors among factors influencing the prognosis of schizophrenia are premorbid interpersonal relationship and adaptive functions. 2) Especially teachers’ reports about school life and peer relationship during school life are useful for predicting the occurrence of schizophrenia in adolescents. We described characteristic and behavioral childhood features which are important in pathogenesis of schizophrenia, based on high-risk studies and long term follow-up studies. Also, pathological profiles of the interpersonal relationship and pathology in adulthood were presented. We tried to integrate various aspects of interpersonal and social weaknesses of schizophrenics applying 'primary and secondary socialization' concept. Finally, five cases of adolescent schizophrenics were described briefly and proposal for the early detection and intervention for risk factors was introduced.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.7
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• pp.97-104
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• 2006

The spray and breakup characteristics of swirling liquid sheet were investigated by measuring the spray angle and breakup length as the axial Weber number Wel was increased up to 1554 and the ambient gas pressure up to 4.0MPa. As Wel and ambient gas density increased, the disturbances on the annular liquid sheet surface were amplified by the increase of the aerodynamic forces, and thus the liquid sheet disintegrated near from the injector exit. The measured spray angles according to the ambient gas density were different before and after the sheet breaks. Before the liquid sheet breaks, the spray angle was almost constant, but once the liquid sheet started to breakup, the spray angle decreased. And the breakup length decreased because of the increase of the aerodynamic force as the ambient gas density and Wel increased. Lastly, the measured breakup length according to the ambient gas density and Wel was compared with the result by the linear instability theory. We found that the corrected linear instability theory considering the attenuation of sheet thickness agrees well with our experimental results.