• Nuclear Engineering and Technology
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• v.38 no.5
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• pp.405-410
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• 2006

Microstructural features and their related mechanical property changes in the 309L cladding and the heat affected zone (HAZ) of SA508 cl.3 steel were investigated through the use of TEM, tensile and small punch (SP) tests. The specimens were irradiated at 563 K up to the neutron fluences of $5.79{\times}10^{19}n/cm^2$ (>1MeV). The microstructure of the clad was mainly composed of a fcc ${\gamma}-phase$, a low percentage of bcc ${\delta}-ferrite$, and a brittle ${\sigma}-phase$. Along the weld fusion line there formed a heavy carbide precipitation with a width of $20{\sim}40{\mu}m$, showing preferential cracking during plastic deformation. The yield stress and ductile-to-brittle transition temperature (DBTT) of the irradiated clads increased. The origin of the hardening and the shift of the DBTT are discussed in terms of the irradiation-produced defect clusters of a fine size and brittle ${\sigma}-phase$.

• Journal of Korea Association of Health Promotion
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• v.2 no.1
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• pp.71-76
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• 2004

The Metabolic syndrome is a constellation of lipid and non-lipid factors of metabolic origin. The presence of any 3 of the following factors is considered sufficient for diagnosis : hypertension(BP <130/85mmHg), low HDL-cholesterol (<40mg% in men, <50mg% in woman), high triglyceride(>150mg%) and abdominal obesity(abdominal girth >102cm in men, 88cm in woman). The major adverse consequence of the metabolic syndrome is cardiovascular disease. Several studies have shown an association between metabolic syndrome and increased cardiovascular events. In Korea, the prevalence of the factor of metabolic syndrome has been increasing since 20 years previously when the Korean economy began to grow rapidly, with a resultant change in lifestyle, toward that of western countries. Thus, the management of the metabolic syndrome is an important social and medical issue in terms of the national health problem. This review will consider each factor in turn, providing insight for health care providers in an effort to prevention of cardiovascular events and maintenance of quality of life in persons with metabolic syndrome was discussed.

• International Journal of Vascular Biomedical Engineering
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• v.2 no.1
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• pp.1-10
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• 2004

Circulatory disease is the number two cause of death next to cancer in Korea, while the cardiovascular disease alone is the number one cause of death in the US. In the present article, some background, current status and future prospects of biomedical engineering esearch on circulatory disorders are discussed in terms of the origin of atherosclerosis, computational fluid dynamics and medical imaging techniques, clinical treatments and fluid dynamics, advances in stents, hemodynamic analysis of artificial heart, and artificial blood. In particular, the importance of close collaboration of medicine and fluids engineering is emphasized.

• Parasites, Hosts and Diseases
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• v.44 no.1 s.137
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• pp.91-94
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• 2006

Recent advances in radiological and serological techniques have enabled easier preoperative diagnosis of sparganosis. However, due to scarcity of cases, sparganosis has been often regarded as a disease of other etiologic origin unless the parasite is confirmed in the lesion. We experienced a case of sparganosis mimicking a varicose vein in terms of clinical manifestations and radiological findings. Sparganosis should be included among the list of differential diagnosis with the varicose vein.

• Journal of Korean Society of Transportation
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• v.12 no.1
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• pp.43-54
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• 1994

The major concern of this paper is to investigate the properties of a stochastic equilibrium for each model system in terms of a consumer welfare measure. The primary assumption for this study is that a trip-maker would choose the trip from his origin zone which maximizes his personal welfare. This assumption, finally, leads to a singly constrained gravity model. The consumer welfare measure is derived from the concept of expected welfare of randomly sampled trip-makers. Each of the four different models considered in this paper is differentiated depending on the complexity of its model or the definition of its travel function. In this study, three different regions are chosen for the purpose of taking into account the effects of different zone-systems on the properties of a stochastic equilibrium : (i) Archerville region (5 zone) ; (ii) San Francisco Bay regions (30 zones) ; (iii) Houston, TX region (199 zones). It is concluded that almost identical, "global" consumer welfare values can be obtained in some cases of the gravity-type trip distribution models based on a stochastic equilibrium.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.50.1-50.1
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• 2015

The origin of globular cluster (GC) color bimodality, which is one of the salient phenomena observed in most large galaxies, has not yet been fully resolved. The phenomenon has conventionally been interpreted as a bimodal metallicity distribution based on an assumption of linear GC color-metallicity relations (CMRs). Recent studies however suggest that nonlinear GC CMRs can cause a bimodal color distribution even from a single-peaked metallicity spread. Using photometric and spectroscopic data on GCs in NGC 5128 (Cen A) and NGC 4594 (Sombrero), we investigate the nonlinearity of GC CMRs and compare the observed GC CMRs with the predictions of stellar population simulation models. Our careful selection of old GCs effectively reduces the scatter and reveals the nonlinear nature of the GC CMRs for various colors. The overall shape of the observed CMRs agrees well with that of the modeled CMRs, while offsets are present for some colors. We discuss the implications of our results in terms of the GC color bimodality and GC formation in NGC 5128 and NGC 4594.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.4
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• pp.507-514
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• 2012

The present study is the analyses of what has been attempted and what was understood in terms of improving the regression rate and enlarging the basic understanding of internal flow dynamics. The first part is mainly intended to assess the role of helical grain configuration in the regression rate inside the hybrid rocket motor. To improve the regression rate, a combination of swirl (which is an active method) and helical grain (which is a passive method) was adopted. The second part is devoted to the internal flow dynamics of hybrid rocket combustion. A large eddy simulation was also performed with an objective of understanding the origin of isolated surface roughness patterns seen in several recent experiments. Several turbulent statistics and correlations indicate that the wall injection drastically changes the characteristics of the near-wall turbulence. Contours of instantaneous streamwise velocity in the plane close to the wall clearly show that the structural feature has been significantly altered by the application of wall injection, which is reminiscent of the isolated roughness patterns found in several experiments.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2006.11a
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• pp.103-116
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• 2006

The recycle economy is the first stage of knowledge economy. In March 2005, the author attended the forum of 'Festival of Thinkers' in the capital of United Arab Emirates, Abu Dhabi. Through five day' discussing with 10 Nobel Prize winners and 18 thinkers from five continents, the conception of Recycle Economy is regulated. The former principle of '3R' in clean production has been expanded to '5R' in new recycle economy, adding concept of 'rethink' and 'repair' to the 'reduce, reuse and recycle' This article makes a full exposition to the origin, contents and its innovation to the classical western economics of the new recycle economics. Before the 2008 Beijing Olympics, the article discusses the application of new recycle economy in terms of promoting the ability of national innovation system and independent innovation, city construction and the industry innovation concerning Beijing's features.

• Journal for History of Mathematics
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• v.13 no.2
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• pp.1-12
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• 2000

The first life tables of the Korean, the so-called Chosun Joomin Saengmyong_Pyo were constructed by Misusima, the head professor, and his faculty members of Preventive Medicine Department, Division of Medical Science, Keijo Imperial University in 1937. The above mentioned life tables were based on the age specific mortality rates by the resident registration and the data of a couple of total population censuses conducted by the Governor of Chosun Government General in 1925 and 1930. And they revealed the following facts: (1) by the first Abridged Life Tables of Korean(Chosunin), the expected life span of Korean male and female were 32 and 35 from 1925 to 1930, respectively. (2) the infant mortality rate of Korean male and female were 252- and 230-person among 1000-born respectively. In conclusion, nobody knows the level of those Life Tables, but it is important in terms of that they are the origin of Korean life tables.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.227-228
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• 2003

The most important of various merits are the capacity to investigate an total genome for polymorphism and AELP is superior to any other systems in terms of the number of sequences amplified per reaction and its reproducibility(Vos et al., 1995). The AFLP technique provides a novel and very powerful DNA fingerprinting technique for DNAs of origin o. complexity (Vos et at., 1995). (omitted)