• Atmosphere
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• v.31 no.1
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• pp.113-141
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• 2021

The impacts of ice clouds on the energy budget of the Earth and their representation in climate models have been identified as important and unsolved problems. Ice clouds consist almost exclusively of non-spherical ice crystals with various shapes and sizes. To determine the influences of ice clouds on solar and infrared radiation as required for remote sensing retrievals and numerical models, knowledge of scattering and microphysical properties of ice crystals is required. A conventional method for representing the radiative properties of ice clouds in satellite retrieval algorithms and numerical models is to combine measured microphysical properties of ice crystals from field campaigns and pre-calculated single-scattering libraries of different shapes and sizes of ice crystals, which depend heavily on microphysical and scattering properties of ice crystals. However, large discrepancies between theoretical calculations and observations of the radiative properties of ice clouds have been reported. Electron microscopy images of ice crystals grown in laboratories and captured by balloons show varying degrees of complex morphologies in sub-micron (e.g., surface roughness) and super-micron (e.g., inhomogeneous internal and external structures) scales that may cause these discrepancies. In this study, the current idealized models representing morphologies of ice crystals and the corresponding numerical methods (e.g., geometric optics, discrete dipole approximation, T-matrix, etc.) to calculate the single-scattering properties of ice crystals are reviewed. Current problems and difficulties in the calculations of the single-scattering properties of atmospheric ice crystals are addressed in terms of cloud microphysics. Future directions to develop physically consistent ice-crystal models are also discussed.

• Journal of Wetlands Research
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• v.23 no.3
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• pp.260-276
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• 2021

Wetlands are constantly affected by internal and external environments that make up the wetlands, and these effects make wetlands change. East Asia countries where about 15% of Ramsar's registered wetlands are located, is valuable conservation area due to various wetland types and biodiversity. However, due to climate change and other factors, the total area of wetlands has been reduced and biodiversity have been damaged. To mitigate these problems and to manage wetlands efficiently, it is important to identify the factors that change wetlands and to identify how each factor affects them. In this study, we conducted a wetland-related literature analysis in East Asia to derive factors that affect the changes in wetlands, and analyzed the relationships among the factors. Finally we presented research directions considering wetland change factors. In most of the East Asia countries, it was found that there is deficiency in research studies about extraction in direct factors and water-energy infrastructure, tourism & recreation in indirect factors. Also, we presented the necessity for future research using the result between connectivity & relationship analysis and indirect drivers of change and their influence on direct drivers of change. The results of this study could contribute to the establishment of an R&D cooperation system in East Asia region and strengthen wetland management.

• Journal of the Korea Society of Computer and Information
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• v.26 no.8
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• pp.197-207
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• 2021

Relationship between bone mineral density (BMD) and type 2 diabetes is still inconsistent. Recently, many epidemiologic data show that fracture risk is increased in type 2 diabetic patients regardless of BMD status. In this study, we used nation-wide data from 2008 to 2011 Korea National Health and Nutrition Examination Survey (KNHANES) to analyze the BMD status in patients with type 2 diabetes compared to non-diabetics. We included subjects aged 50 years or older in men (N=2,959, 2,430 without diabetes, 529 with type 2 diabetes) and postmenopausal women (N=2,902, 2,479 without diabetes, 423 with type 2 diabetes). Subjects with history of medication for osteoporosis or with illness or malignancy affecting bone metabolism were excluded. Data of anthropometric measurements and demographic characteristics were collected by trained examiner. Serum was separated from peripheral venous blood samples obtained after 8 hours of fasting. BMD was measured at lumbar spine and femur using dual-energy X-ray absorptiometry (DXA). There was a significant positive association between lumbar spine BMD and type 2 diabetes after adjusting age, gender, body mass index, monthly house income, education level, physical activity, daily calcium intake and vitamin D concentration by multiple regression analysis in all subjects. In the subgroup analysis by gender, this association was maintained both in male and female after adjusting those confounding factors. However, femur BMD was not different between type 2 diabetic and non-diabetic subjects. In conclusion, lumbar spine BMD was significantly higher in type 2 diabetic patients aged 50 years or more in men and postmenopausal women compared to non-diabetic subjects.

• Journal of Preventive Medicine and Public Health
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• v.54 no.6
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• pp.412-421
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• 2021

Objectives: Non-alcoholic fatty liver disease (NAFLD) is an increasingly prevalent metabolic disease. Muscle is known to influence NAFLD development. Therefore, this study aimed to determine the relationships among low muscle mass, NAFLD, and hepatic fibrosis using various definitions of low muscle mass and NAFLD diagnostic methods, including magnetic resonance imaging-based proton density fat fraction (MRI-PDFF). Methods: This cross-sectional study included 320 participants (107 males, 213 females) from the Korean Genome and Epidemiology Study on Atherosclerosis Risk of Rural Areas in the Korean General Population cohort. Muscle mass was assessed using whole-body dual-energy X-ray absorptiometry and adjusted for the height squared, body weight, and body mass index (BMI). NAFLD was diagnosed using ultrasonography (US), MRI-PDFF, and the comprehensive NAFLD score (CNS). Hepatic fibrosis was assessed using magnetic resonance elastography. Multivariable logistic and linear regression analyses were performed to determine the aforementioned associations. Results: According to US, 183 participants (57.2%) had NAFLD. Muscle mass adjusted for body weight was associated with NAFLD diagnosed using US (odds ratio [OR], 3.00; 95% confidence interval [CI], 1.70 to 5.31), MRI-PDFF (OR, 2.00; 95% CI, 1.13 to 3.53), and CNS (OR, 3.39; 95% CI, 1.73 to 6.65) and hepatic fibrosis (males: β=-0.070, p<0.01; females: β=-0.037, p<0.04). Muscle mass adjusted for BMI was associated with NAFLD diagnosed by US (OR, 1.71; 95% CI, 1.02 to 2.86) and CNS (OR, 1.95; 95% CI, 1.04 to 3.65), whereas muscle mass adjusted for height was not associated with NAFLD. Conclusions: Low muscle mass was associated with NAFLD and liver fibrosis; therefore, maintaining sufficient muscle mass is important to prevent NAFLD. A prospective study and additional consideration of muscle quality are needed to strengthen the findings regarding this association.

• Journal of the Korean Institute of Gas
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• v.26 no.6
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• pp.9-15
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• 2022

In order to verify the durability of the high-pressure hydrogen tank in the operating pressure range, a hydraulic rupture test should be performed. However, if the bubbles generated by the initial injection process of water are attached to the inner wall of the tank and remain, a sudden pressure change of the bubbles during the rupture of the pressurized tank may cause shock and noise. Therefore, in this study, the flow velocity required to remove the bubbles remaining on the inner wall of the tank was predicted through simplified formulas, and the shape of the injection nozzle to maintain the flow velocity was determined based on the shape of the hydrogen tank for the hydrogen bus. In addition, a numerical model was developed to predict the change in flow velocity according to the inlet pressure, and an experiment was performed through a model tank to prove the validity of the prediction result. As a result of the experiment, the flow velocity near the tank wall was similar to the predicted value of the analysis model, and when the inlet pressure was 1.5 to 5.5 bar, the minimum size of the removable bubble was predicted to be about 2.2 to 4.6 mm.

• Asia Marketing Journal
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• v.21 no.4
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• pp.25-43
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• 2020

Although ready meals have recently increased their market share in the Korean food industry, a literature review found that the use of ready meals triggers feelings of guilt in homemakers. Such guilt arises as a result of several factors apparently related to consumers' health. Consequently, levels of guilt might be expected to vary depending on consumers' perceived health locus. The present study aims to examine (a) how health locus affects guilty feelings about ready-meal consumption, (b) how the effect varies in relation to the consumption of different types of ready meal, and (c) the relationship between consumers' guilty feelings and willingness to buy ready meals. Three dimensions of health locus of control (HLC) -internal HLC (IHLC), powerful-others HLC (PHLC), and chance HLC (CHLC)- were presumed to influence consumers' feelings of guilt in association with ready meals. Data were collected via an online survey, and participants were randomly assigned to either of two groups: one group was instructed to heat meals in a microwave (ready-to-heat [RTH] group, n=104) and the other cooked using a pan with additional ingredients (ready-to-cook [RTC] group, n=101). The study found that guilty feelings about consuming RTH meals increased in line with increased external HLCs, namely, PHLC and CHLC. For the RTC group, guilt increased in line with increased PHLC. IHLC had no significant effect on guilty feelings in either group. Willingness to buy ready meals decreased for both groups as consumers' feelings of guilt increased. Even RTC meals, which require more time and energy in food preparation, did not reduce guilty feelings among consumers with higher PHLC. RTC meals are preferable for consumers with higher CHLC, since their sense of greater involvement in the cooking process alleviates their feelings of guilt. Cooking with already prepared and uncooked ingredients brought fun and joy, both for the participants and their significant others. This interpretation may be developed into a strategic plan by ready-meal producers to strengthen their marketing strategy.

• Journal of the Korean Society of Radiology
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• v.16 no.4
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• pp.381-386
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• 2022

Non-Destruction Test (NDT) is a method to check internal defects without destroying the product. Among them, radiographic testing (RT) uses high-energy radiation, so it is very important to prevent radiation exposure of workers. Therefore, in this study, in this study, a radiation sensor structure that improves radiation detection performance compared to the existing PbI₂ and can immediately detect accidents in RT was presented. For evaluation, the conversion efficiency was analyzed in the gamma ray source through FLUKA simulation. PbI₂ with overlapping Gd₂O₂S:Tb presented in this study showed a higher radiation sensitivity from 1.22 to 3.22 times than that of non-overlapping PbI₂. This indicates that the presented sensor is suitable for use as a radiation sensor for source detection in RT.

• Journal of Aerospace System Engineering
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• v.16 no.5
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• pp.62-69
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• 2022

EHA (Electro-Hydrostatic Actuator) is more energy efficiency than a centralized hydraulic system. In particular, the EHA used for aircraft has a redundant design in preparation for failure scenario. Also, due to the aircraft's internal space limitation, the actuator's length must be optimized. Therefore, a series configuration of double rod and single rod cylinder is advantageous. However, due to the asymmetry of the cross-sectional area of the piston, the force fighting phenomenon between the two cylinder areas occurs during redundant operation with a general control system. In this paper, the force fighting phenomenon of redundant EHA was simulated. A controller with load compensation and a force control-based position controller as a method to suppress its stimulation

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.296-301
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• 2023

Solid oxide fuel cell has received more attention recently due to the fuel flexibility via internal reforming. Commonly used Ni/YSZ anode, however, can be easily deactivated by carbon coking in hydrocarbon fuels. The carbon deposition problem can minimize by developing alternative perovskite anode. This study is focused on improving conductivity and catalytic activity of the perovskite anode by introducing rGO (reduced graphene oxide). Sr_0.92Y_0.08TiO₃(SYT) anode with perovskite structure was synthesized with 1wt% of rGO. The presence of rGO during anode fabricating process and cell operation is confirmed through XPS and Raman analysis. The maximum power density of rGO/SYT anode improved to 3 times in H₂ and 6 times in CH₄ comparing to that of SYT anode due to the high electrical conductivity and good catalytic activity for CH₄.

• Journal of Daesoon Thought and the Religions of East Asia
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• v.2 no.2
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• pp.33-50
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• 2023

'Fasting of the Mind (心齋, ch. xīn zhāi)' is arguably the most important concept within the practical approach to the spiritual cultivation formulated by the Daoist philosopher, Zhuangzi (莊子). Most scholars have interpreted 'Fasting of the Mind' as an apophatic practice centered around the aim of the 'Dissolution of the Self (喪我, ch. sàng wŎ).' The Korean new religious movement, Daesoon Jinrihoe (大巡眞理會), can be shown to instead consistently utilize cataphatic descriptions of spiritual cultivation based on the 'quieting of the mind (安心, kr. anshim)' and 'quieting of the body (安身, kr. anshin)' with the highest attainable state referred to as the 'Perfected State of Unification with the Dao (道通眞境, kr. Dotong-jingyeong).' While the language used by Zhuangzi and Daesoon Jinrihoe appears quite different on a superficial level, a deeper examination shows that these rhetorical framings are likely negativistic and positivistic descriptions of the same, or at least reasonably similar, phenomena. Zhuangzi, who focused primarily on the body, mind, and internal energy, cautioned practitioners that 'mere listening stops with the ears (聽止於耳, ch. tīng zhǐ yú ěr)' and 'mere recognition stops with the mind (心止於符, ch. xīn zhǐ yú fú).' He therefore encouraged cultivators of the Dao to 'listen with the spirit (聽之以氣 ch. tīng zhī yǐ qì).' The main scripture of Daesoon Jinrihoe states that "The mind is a pivot, gate, and gateway for gods; They, who turn the pivot, open, and close the gate, and go back and forth through the gateway, can be either good or evil (心也者, 鬼神之樞機也, 門戶也,道路也)," and the Supreme God of the Ninth Heaven (九天上帝, kr. Gucheon Sangje) even promises to visit anyone who possesses a 'singularly-focused mind (一心, kr. il-shim).' In both these approaches, there is a sense of what must be kept out of the mind (e.g., external disturbances, strong emotions, malevolent entities) and what the mind should connect with to attain spiritual progress (e.g., spirit, singular focus, the Supreme God). The observations above serve as the main basis for a comparison between the apophatic descriptions of cultivation found in Zhuangzi and their cataphatic counterparts in Daesoon Thought. However, the culmination of this nuanced comparative exploration reveals that while the leanings of Zhuangzi and Daesoon Thought generally hold true, ultimately, both systems of cultivation transcend the categories of apophatic and cataphatic.