• Journal of The Korean Astronomical Society
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• v.53 no.3
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• pp.69-75
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• 2020

We study the photometric phase curves for the planets of our solar system which can be considered as a prototypical non-compact planetary system. We focus on modeling the small variations caused by three effects: reflection, ellipsoidal, and Doppler beaming. Theoretical predictions for these photometric variations are proposed, considering a hypothetical external observer. Unlike similar studies of multi-planetary systems, the physical and geometrical parameters for each planet of the solar system are well-known. Therefore, we can accurately evaluate the relationships that shape the planetary light curves for a fictitious external observer. Our results suggest that, for all planets, the ellipsoidal effect is very weak while the Doppler beaming effect (DBE) is, in general, dominant. In fact, the DBE seems to be the principal cause of variations of the light curves for the planets of the solar system. However, for Mercury and Venus the Doppler beaming and reflection effects have similar amplitudes. The phase curves obtained for the planets of the solar system show new interesting features of interest for the study of other non-compact planetary systems.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.2
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• pp.223-229
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• 2004

Combustion using oxygen enriched air is known as a technology which can increase thermal efficiency due to increase of the flame temperature. Flame shapes, schlieren photos, OH radical chemiluminescence and local flame temperature were examined as a function of OEC(Oxygen Enriched Concentration) in a coaxial non-premixed jet. With increase of OEC, flame length and width decreased, but its brightness increased significantly, and the size of vortices in the flame also increased. Especially, the reaction around the flame surface became active. The strong OH intensity appeared to be made and moved from middle stream to upper one with increase of OEC, which shows combustion reaction in the upper stream becomes more dominant In addition, the temperature distributions of the flames showed similar tendency with OH radical intensities. A flame with high temperature and strong stability was obtained with increasing OEC of the coflow.

• Investigative Magnetic Resonance Imaging
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• v.20 no.1
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• pp.36-43
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• 2016

Visualization of the tissue loss tangent property can provide distinct contrast and offer new information related to tissue electrical properties. A method for non-invasive imaging of the electrical loss tangent of tissue using magnetic resonance imaging (MRI) was demonstrated, and the effect of loss tangent was observed through simulations assuming a hyperthermia procedure. For measurement of tissue loss tangent, radiofrequency field maps ($B_1{^+}$ complex map) were acquired using a double-angle actual flip angle imaging MRI sequence. The conductivity and permittivity were estimated from the complex valued $B_1{^+}$ map using Helmholtz equations. Phantom and ex-vivo experiments were then performed. Electromagnetic simulations of hyperthermia were carried out for observation of temperature elevation with respect to loss tangent. Non-invasive imaging of tissue loss tangent via complex valued $B_1{^+}$ mapping using MRI was successfully conducted. Simulation results indicated that loss tangent is a dominant factor in temperature elevation in the high frequency range during hyperthermia. Knowledge of the tissue loss tangent value can be a useful marker for thermotherapy applications.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.4
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• pp.367-381
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• 2011

Reducing waste for the efficiency of production is becoming more important because of the rapidly changing market circumstances and the rising material and oil prices. The dispatching also has to consider the characteristic of production circumstance for the efficiency. The production circumstance has the non-identical parallel machines with rework rate since machines have different capabilities and deterioration levels in the real manufacturing field. This paper proposes a dispatching method, FTLR (Flow Time Loss Index with Rework Rate) for production efficiency. The goal of FTLR is to minimize flow time based on such production environments. FTLR predicts the flow time with rework rate. After assessing dominant position of expected flow time per each machine, FTLR performs dispatching to minimize flow time. Experiments compare various dispatch methods for evaluating FTLR with mean flow time, mean tardiness and max tardiness in queue.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.8
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• pp.853-862
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• 2006

The present study is numerically investigated the flame structure of non-premixed counterflow jet flames using the laminar flamelet model Detailed flame structures with the fuel composition of 40% CO, 30% $H_2$. 30% $N_2$ and an oxidizer composition of 79% $N_2$ and 21% $O_2$ in a non-premixed counterflow flame are studied numerically. This study is aimed to investigate the effects of axial velocity gradient and combustion atmosphere pressure on flame structure. The results show that the role of axial velocity gradient on combustion processes is globally opposite to that of combustion atmosphere pressure. That is, chemical nonequilibrium effects become dominant with increasing axial velocity gradient, but are suppressed with increasing ambient pressure. Also, the flame strength is globally weakened by the increase of axial velocity gradient but is augmented by the increase of ambient pressure. However, flame extinction is described better on the basis of only chemical reaction and in this study axial velocity gradient and ambient pressure play a similar role conceptually such that the increase of axial velocity gradient and ambient pressure cause flame not to be extinguished and extend the extinction limit, respectively. Consequently it is suggested that a combustion process like flame extinction is mainly influenced by the competition between the radical formation reaction and the third-body recombination reaction.

• Journal of Trauma and Injury
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• v.22 no.2
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• pp.161-166
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• 2009

Purpose: This study was conducted to analyze chest-trauma patients and the old-aged patients with a traumatic hemopneumothorax. Methods: We reviewed the medical records of 101 chest-trauma patients admitted to the department of cardiovascular and thoracic surgery from June 1999 to November 2008. We evaluated the general characteristics of the chest-trauma patient, especially those of old-aged patients with a traumatic hemopneumothorax. Results: Rib fracture was observed in 99 of the cases, the location distribution was right: left =261: 255, with right being dominant. Rib fractures commonly involved the 4th and the 7th rib. The average number of rib fractures was 5.1, and the average number of rib fractures in the old-aged patients was significantly higher than that in the non-old-aged patients (p=0.04). There were 17 cases of a hemopnuemothorax in old-aged patients, 52 cases in non-old-aged patients. The blood loss through the chest tube for old-aged patients was significantly more than that for the non-old-aged patients, and the initial hemoglobin level was lower in the old-aged patients. Conclusion: Elderly trauma patients are more likely to die after trauma than other age groups. Even with relatively stable vital signs, invasive hemodynamic monitoring and intensive treatment are recommended.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.3
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• pp.250-254
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• 2011

The study was carried out to evaluate the affect of proton beam radiation on production of bulbil and tuber including change of endogenous gibberellins, of Dioscorea opposita Thunb. The yield of bulbils and tubers from non- and irradiated D. opposita Thunb at doses of 5, 10, 15 and 20 Gy were determined. Endogenous gibberellins were also quantified by GC/MS analysis. D. opposita tubers irradiated at 15 Gy produced higher bulbil production than non-irradiated plants. Enlarged bulbil (above size diameter 4 mm) was significantly increased at 15 Gy. Bioactive endogenous $GA_4$ was dominant in bulbils and tubers irradiated with proton beam rather than $GA_1$. Major gibberellins biosynthetic pathways in bulbils and tubers of D. opposita plants were non C-13 hydroxylation route. From the results of this study, 15 Gy proton beam radiation was suggested as an optimal dose that can produce high amounts of bulbil for mass production of D. opposita plant.

• Journal of The Geomorphological Association of Korea
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• v.25 no.4
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• pp.21-35
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• 2018

The distribution and size of sandy beaches along eastern Korea has a close relationship with the presence of granite rocks. In general, elongated and wide beaches with abundant sands are likely to develop along the coasts where granitic basic rocks comprise the dominant geology or where a large amount of sands are supplied by streams from inland granitic rocks. Small sandy beaches, in contrast, appear in non-granitic rocks (i.e., under sedimentary and/or metamorphic geology). Hence, large beaches are observed continuously along the shore of Gangwon-do, of which coasts consist predominantly of granitic geology. Such continuity declines from Samcheok city to Pohang city. The rock of Gyeonbuk-do is commonly known as sedimentary, deposited between the late Triassic and the early Tertiary Periods. Because few sands are supplied from the upstream areas, sandy beaches unlikely develop along the coasts of the province, only showing a sporadic, discontinuous distribution under Bulguksa granite, granitic gneiss, and some volcanic rocks. Erosion was rarely observed in the beaches where granitic rocks are distributed, whereas merely five beaches seemed to have undergone some level of erosion in non-granitic regions. This is presumably because a larger amount of sands than that which had been eroded away was replenished in areas under granitic geology, while under non-granitic geology having a deficit in sands, no large sandy beaches had formed at first.

• Journal of the Korean institute of surface engineering
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• v.55 no.5
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• pp.273-283
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• 2022

Al6061 aluminum alloy specimens were exposed to atmospheric conditions for maximum 24 months. 24-month exposure specimen showed some more frequent and larger size of corrosion products and pitting on the surface compared with the 12-month exposure specimens. The XRD examination revealed the dominant surface oxide phases of Al₂O₃ and Al(OH)₃. The oxide thickness at uniform oxidation (or non-pitting) region was not much changed over exposure time. The 1.2 ㎛ deep oxygen penetration area was found in the 12-months exposed specimen near the thin uniform aluminum oxide film. The line-EDS was conducted through the penetration regions and non-penetrated grain boundary. There were signs of O and Si concentration through the penetration region, whereas non-penetration region showed no concentration of O or Si. It was confirmed that pitting is a more severe degradation mode in Al6061 (max. >4 ㎛ deep) compared with the uniform oxidation (max. ~200 nm deep) up to 24-months exposure.

• Journal of Nutrition and Health
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• v.55 no.6
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• pp.684-698
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• 2022

Purpose: Recent studies have reported a significant association between skeletal muscle, muscle strength and non-alcoholic fatty liver disease (NAFLD). The effect of nutrient intake on the prediction of skeletal muscle mass and strength or its suggested correlation with metabolic diseases has been primarily reported in healthy individuals. The current study explores the association between energy intake and handgrip strength (HGS) in individuals with NAFLD. Methods: Data were obtained from the Korea National Health and Nutrition Examination Surveys 2016-2018. Data from 12,469 participants were extracted and 1,293 men and 1,401 women aged 20 years and older were included in the analyses of patients with NAFLD. The presence of NAFLD was determined using the hepatic steatosis index. To estimate relative skeletal muscle strength, HGS was measured using a digital dynamometer and calculated by adjusting the body mass index of the dominant arm. Study subjects in the NAFLD and non-NAFLD groups were separately categorized according to quartiles of the calculated HGS. Results: We found that individuals with low (EQ1) energy intake had lower odds of HGS compared to subjects with high (EQ4) energy intake, irrespective of their NAFLD status (p < 0.0001). However, the HGS did not differ based on the level of protein or fat intake ratio. Additionally, the effect of energy intake on HGS was more pronounced in men than in women. Conclusion: Energy intake was associated with the risk of weak HGS in men with NAFLD. The results indicate that energy intake may be a key factor in nutrition care for NAFLD patients with low muscle function.