• Sleep Medicine and Psychophysiology
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• v.5 no.1
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• pp.54-70
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• 1998

Objectives : The purpose of this study is to evaluate the role of structural and functional changes of the brain in the pathophysiology of schizophrenia. Methods : The authors measured the regions of interest on the magnetic resonance imaging of the brain in 20 patients with paranoid schizophrenia(15 men and 5 women) and 23 control subjects(15 men and 8 women). We also assessed the neurocognitive functions with the Wisconsin Card Sorting Test, the Benton Neuropsychological Assessment, and the Weschler IQ test-Korean version, soft neurologic signs, and psychiatric symptoms in the patient group. Results : In the patient group, all ventricles and basal ganglia including caudate nucleus and globus pallidus were significantly enlarged. Although there were no significant differences between the two groups in the values of right frontal lobe and left temporal lobe, there was a tendency of decrease in the values of right frontal lobe and left temporal lobe. There were significant positive correlations between the values of ventricles and the frequency of previous hospitalization. However, there were no significant correlations between other values of regions of interest and clinical data. The value of the right frontal lobe was significantly correlated with the score of soft neurologic signs, which is suggestive of the neurodevelopmental abnormalities. There were significant correlations between the value of frontal lobe and the scores of the various subscales of Benton Neuropsychiatric Inventory. In contrast, the value of left amygdala and putamen showed significant correlation with the score of verbal IQ on the Weschler IQ test. Structural changes of the temporal lobe areas were related with the positive and general symptom scores on PANSS, while those of the basal ganglia were related with the negative symptom scores. Conclusions : These results suggest that the structural changes of the brain in the patients with schizophrenia show the dual process, which is suggestive that the enlarged ventricle show the neurodegenerative process, while enlarged basal ganglia, and shrinked right frontal and left temporal lobe show the neurodevelopmental abnormalities. Among these changes, structural changes of the frontal lobe related with various neuropsychological deficits, while those of left temporal lobe related with language abnormality. Relative to the relation between structural changes and psychiatric symptoms, structural changes of the temporal lobe areas were related with the positive and general symptoms, while those of the basal ganglia were related with the negative symptoms.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.112-112
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• 2003

Telomere란 진핵세포에 존재하는 DNA-protein 복합체로서 염색체의 말단부에 tandem repeated DNA 서열 (TTAGGG)과 특정 단백질로 구성되어 있으며 세포 분열이 진행함에 따라 이의 길이가 짧아지게 되고 일정 길이 이하가 되면 세포의 사망이 유발된다. 반면 telomerase는 ribonucleoprotein으로서 telomeric DNA의 합성에 관여하는 것으로 염색체의 말단에 telomeric DNA의 소실을 보충하는 역할로 알려져 있다. 최근 암, 노화 등과 관련하여 telomere 및 telomerase의 연구들이 활발히 진행되고 있으며, 다양한 세포들에 있어 이들의 존재와 역할에 대해서도 많은 연구들이 수행되고 있다. 포유동물의 초기 배자에 있어 telomere의 분포 양상과 telomerase의 activity의 분석은 배 발생의 기작과 배자의 세포적 특성을 구명하는데 매우 중요한 과제라 사료된다. 따라서 본 연구에서는 마우스의 초기 배 발생 단계별 수정란의 telomeric DNA의 분포 양상과 각 단계별 배자들의 telomerase activity를 제시하고자 하였다. 시험에 공시된 마우스는 4-6주령된 ICR계통으로 이들을 과배란 처리 후 자연 교배시켜 얻은 2-, 4-, 8-세포기배, 상실배 및 배반포배를 대상으로 하였다. Telomeric DNA의 양적 분석은 각 발생단계별 수정란의 표본을 제작하고 human telomere repeat probe를 이용하여 FISH (fluorescence in situ hybridization)를 시행하였으며, 분리된 할구들을 형광현미경으로 관찰 후 상을 포착하고 image analyser program (MataMorph, UIC, USA)을 이용하여 한 개의 세포내 telomere의 상대적 함량을 분석하였다. 발생 단계별 배자의 telomerase activity의 분석은 TRAP (telomeric repeat amplofication protocol) assay로 분석한 바 각 발생 단계별 30개의 수정란으로부터 핵 단백질을 추출하여 telomerase를 신장시키고 PCR을 시행한 후 15% PAGE gel loading하여 이의 activity를 확인하였다. 분석 결과, telomeric DNA의 함유율은 발생단계별 다소의 차이를 나타내었으며 telomerase activity는 모든 발생단계의 수정란에서 확인할 수 있었고, 특히 상실배부터 높게 나타남을 확인하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.5
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• pp.645-652
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• 2010

The aim of this investigation was study on the non-evaporation diesel spray characteristics injected through a common-rail diesel injector under various ambient pressure. The diesel spray was investigated with observation of macroscopic characteristics such as spray tip penetration and spray cone angle by the shadowgraph and the image processing method. The numerical study was conducted using a computational fluid dynamics code, AVL-FIRE. The breakup models used were WAVE model and standard $k-{\varepsilon}$ turbulence model was applied. The numerical study used input data which spray cone angle and fuel injection rate was achieved by Zeuch's method. Comparison with experimental result such as spray tip penetration was good agreement. Distribution of droplet diameter were conducted on four planes where the axial distances were 5, 15, 39 and 49mm respectively downstream from the orifice exit.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.4
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• pp.68-76
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• 2016

This research is carried out for the performance evaluation of the injector that is one of the critical components of bipropellant-rocket-engine. Spray characteristics are investigated in detail according to the recess length and injection pressure on the swirl-coaxial-injector using gaseous methane and liquid oxygen as propellants. A visualization is conducted by the Schlieren photography that is composed of a light source, concave mirrors, knife, and high-speed-camera. A hollow-cone-shape is identified in the liquid spray that is spread only by inner injector and the spray angle is decreased due to the diminution of swirl strength in accordance with the increase of the length of injector orifice. When the injector sprays the liquid through the inner injector with the aid of gas through the outer injector, the spray angle in external mixing region tends to increase with rise of the recess length, while in internal mixing region, it is decreased. It is also confirmed that the same tendency of the spray angle with recess length appears irrespective of the injection pressure of liquid spray.

• Korea and Global Affairs
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• v.1 no.1
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• pp.31-70
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• 2017

On December 9, 2016, the decision of impeachment of the National Assembly decided against Park Geun-hye came from the nomination conflicts of the 20th general election between Pro-Park group and Anti-Park group at the ruling Saenuri Party. Therefore, this study focused on the nomination conflicts of the ruling party and the opposition party on the election results in the 20th general election on the public sentiment of the people. The nomination conflicts of the ruling and opposite parties were a prelude to the victory of the 19th presidential election, and it was serious faction conflict. Firstly, the study examined how the nomination conflicts of each party were centered on President Park Geun-hye as well as the leaders of each party and the chairman of the nomination committee. Secondly, the study examined what kind of changes would be made to the composition of presidential candidates for each party at the time of the presidential election. Thirdly, the study examined the opposition parties' separation between the Minjoo Party of Korea and the People's Party of Korea before and after the election and the issue of initiative in Honam. As a result of the analysis, the 20th general election failed to obtain a majority seat of the ruling Saenuri Party, and the opposition won and formed the majority. The reason why President Park and Saenuri were greatly defeated in the contest even in the situation where the opposition parties were divided is the root cause in the attitude of Pro-Park group and Anti-Park group who assumed their victory. Therefore, it is highly possible to render its responsibility to President Park Geun-hye, who has become a 'past power', and it has opened up the possibility that the emergence of future power by opposition parties. In the case of the opposition party, it is clear that the battle for Honam, which is a traditional opposition party's support group, is a matter of good fortune of the two major powers, Moon Jae In and Ahn Cheol Soo.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.6
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• pp.59-67
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• 2006

Particles of soil are crushed when soil is compacted in the in-situ or lab. Among many factors that affect the crush of particles, compaction energy is a major factor. Because the crush of particles can change physical properties, the analysis of effect of compaction energy is very important. In this study, the fragmentation fractals were used for determining the change in grain size distribution and the effect due to change in grain size distribution was estimated. Compaction energy was increased by 50, 100, 200 and 300% based on the energy of standard A compaction test. As a result, grain size distribution curves were changed and fine particles increased as compaction energy were increased. Relative compaction were ranged between $93.38{\sim}107.67$. Fractal dimension of each site increased as compaction energy increased. Relative compaction is proportional to the fractal dimension but coefficients of permeability were in inverse proportional to the involution of fractal dimension.

• Journal of ILASS-Korea
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• v.9 no.1
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• pp.21-29
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• 2004

The flow characteristics of a swirl injector were investigated with the variation of the flow condition and geometric dimensions, such as orifice length for considering the viscous effect and tangential entry port area for considering the swirl intensity. The liquid film thickness strongly influencing on the formed drop size of the spray was measured using a new technique. The film thickness measurement technique proposed here, used the attenuation of fluorescence signal near the injector exit. The breakup length that is important for the flame location as well as the spray cone angle which influences on the ignition performance was measured using a backlit stroboscopic photography technique. From the experimental results, it is found that an increase in injection pressure decreased the film thickness and breakup length, and also enlarged the spray cone angle. A decrease in orifice length and tangential entry port area has a similar tendency of thinner film thickness, shorter breakup length and larger spray cone angle. In the present study, we proposed empirical models of the flow characteristics of the swirl injectors.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.3
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• pp.9-17
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• 2006

The influences of recess length of a liquid/liquid swirl coaxial injector on spray characteristics were investigated. It was revealed that the internal impinging phenomenon played an important role in the spray characteristics, such as spray angle and breakup length. Also, as the recess length increased, the mean drop size increased due to the increase of effective film thickness and mixing efficiency increased, but in the case of very deep recess length, the mixing efficiency decreased.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.7
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• pp.871-880
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• 1999

In this paper an experimental study is presented of the problem of dynamic behavior of a water droplet impinging upon a heated surface. The experiments are mainly focused on the effects of impinging angle of a droplet and surface temperature on the impact dynamics of the droplet. It Is clarified that the droplet exhibits much different behavior depending on the normal momentum of an impinging droplet before impact. At surface temperature In the nucleate boiling regime. the disintegration of a droplet doesn't occur, whereas the deforming droplet adheres to the surface. The spreading and contraction of the liquid film is repeated a couple of times for the horizontal surface but the expanded droplet just slips without noticeable contraction for the inclined surfaces. In the film boiling regime, the impinging droplet spreads over the surface as a liquid film which is separated from the surface by produced vapor. Depending on the magnitude of the normal momentum of the droplet the disintegration into the several irregular shapes of liquid elements occurs for the horizontal and 30o-inclined surfaces, whereas the impinging droplet for the 60o-inclined surface doesn't break up and tends to recover the original spherical shape.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.12
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• pp.971-978
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• 2007

A spray-wall impingement process of a hollow-cone fuel spray from the high-pressure swirl injector in the Gasoline Direct Injection (GDI) engine were experimented and calculated at various wall geometries. The Linearized Instability Sheet Atomization (LISA) & the Aerodynamically Progressed Taylor Analogy Breakup (APTAB) model and the Gosman model were applied to model the breakup and the wall impingement process of the hollow-cone fuel spray. The numerical modelings were implemented in the modified KIVA code. The calculation results of spray characteristics, such as a spray development process and a radial distance after wall impingement, compared with the experimental results by the Laser Induced Exciplex Fluorescence (LIEF) technique. The droplet size distribution and the ambient gas velocity field, which are generally difficult to obtain by the experimental methods, were also calculated and discussed. It was found that the radial distance after wall impingement and Sauter Mean Diameter (SMD) decreased with increasing a cavity angle.