• Journal of the Korean Wood Science and Technology
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• v.41 no.5
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• pp.466-473
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• 2013

Nondestructive evaluation (NDE) technique method using a resonance frequency mode was carried out for heat-treated wood under different conditions. The effect of heat treatment on the bending strength and NDE technique using the resonance frequency by impact hammer and force transducer mode for Korean paulownia, Pinus densiflora, Lidiodendron tulipifera and Betula costata were measured. The heat treatment temperature has been investigated at $175^{\circ}C$ and $200^{\circ}C$, respectively. There were a close relationship of dynamic modulus of elasticity and static bending modulus of elasticity to MOR. In all conditions, It was found that there were a high correlation at 1% level between dynamic modulus of elasticity and MOR, and static modulus of elasticity and MOR. However, the result indicated that correlation coefficient is higher in dynamic modulus of elasticity to MOR than that in static modulus of elasticity to MOR. Therefore, the dynamic modulus of elasticity using resonance frequency by impact hammer mode is more useful as a nondestructive evaluation method for predicting the MOR of heat-treated wood under different temperature and species conditions.

• Journal of Korean Public Health Nursing
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• v.36 no.2
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• pp.170-183
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• 2022

Purpose: This descriptive survey-based study aimed to identify the factors associated with obese adults' quality of life (QOL) using a secondary analysis of data collected through the 8th Korea National Health and Nutrition Examination Survey (2019). Methods: In this study, factors affecting the health-related quality of life of obese adults were analyzed by categorizing them into three independent variables: general characteristics, health behaviors, and mental health characteristics. Using t-test and analysis of variance (ANOVA), an analysis was performed to determine the differences in obese adults' QOL depending on their general characteristics, health behaviors, and mental health conditions. A hierarchical regression analysis was performed to identify the factors that affect obese adults' QOL. Results: In obese adults' general characteristics, the risk factors for QOL were older age, male, lower-income level, presence of spouse, and occupation. With regard to health behaviors, the risk factors were lack of exercise. In terms of mental health conditions, the risk factors were stress and suicidal ideation. Conclusion: Obese adults' QOL was affected by age, sex, income level, absence/presence of a spouse, occupation, health behaviors (e.g., exercise), and mental health conditions (e.g., stress and suicidal ideation).

• The Journal of Korean Academic Society of Nursing Education
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• v.28 no.1
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• pp.15-26
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• 2022

Purpose: The purposes of this study was to describe the lived experience structures of married immigrant women with chronic diseases in reorganizing their lives in a variety of situations and contexts. Methods: This study applied grounded theory approach, and the participants were 15 married immigrant women with chronic disease. Data were collected through individual in-depth interviews and then analyzed by the method in Strauss and Corbin (1998). Results: The extracted data were organized 41 concepts, 21 subcategories, and 8 categories. The central phenomenon was determined to be "Life turned into a chronic disease." The causal conditions were "Undergoing physical and mental stress from marriage", "Lack of information on chronic diseases." The extracted contexts was "The demand for health resources." action and interaction strategies, "Finding problems and solutions." The intervention conditions influencing the strategies was "Establishing a support system." The result of such action was "To settle down in a way of life that suits your conditions." Conclusion: By providing a comprehensive and integrative understanding of how married immigrant women with chronic disease reorganize their lives, the study is expected to contribute to the development of social systems and national policies.

• Korean Journal of Medicinal Crop Science
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• v.20 no.5
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• pp.393-397
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• 2012

This study was investigated seed germination of Rheum undulatum L. depends on storage temperature (-20, $5^{\circ}C$ and room temperature), germination temperature (5, 15, 25 and $40^{\circ}C$) and a soaking treatment (no soaking, 2 days and 4 days). There was not much difference from the germination rate of R. undulatum L. in storage temperature conditions for 8 weeks. The highest of germination rate occurred over 80 percentage at $25^{\circ}C$. When R. undulatum L. was soaked with tap water for four days, the average values of germination velocity and germination day were represented of 1.7 ea/day and 1.68 days. These results may help our understanding of variations in germination characteristics for R. undulatum L. seeds treated under various germination conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.283-290
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• 2020

The purpose of this study was to investigate the potential causal relationship between unmet healthcare needs and metrics related to quality of life. To examine the relationships between these variables, the study conducted an analysis by processing additional irradiated raw materials of the Korean Medical Panel. The metrics related to quality of life included six variables: athletic ability, self-care, daily activities, pain/trouble, uneasiness/depression, and subjective health conditions. Linear regression analysis revealed that the unmet healthcare needs had statistically significant negative effects on all six quality of life variables. A review of the magnitude of the linear regression β values for those variables showed that the relative level of influence on the quality of life variables decreased in the following order: pain/trouble, subjective health conditions, uneasiness/depression, daily activities, athletic ability, and self-care. Based on the results, practical applications related to strengthening working-level links between health and welfare is considered an effective policy response to the continued presence of unmet healthcare needs; such applications could contribute to improving the quality of life of those with unmet healthcare needs.

• Journal of Microbiology
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• v.41 no.1
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• pp.34-40
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• 2003

Aspergillus nidulans, a homothalic ascomycete, has a complete sexual reproductive cycle as well as an asexual one. Both sexual and asexual development are known to be genetically programmed, but are also strongly affected by environmental factors including nutrients, light, temperature and osmolarity. We have examined these factors to define favored conditions for fruiting body (cleistothecium) formation. In general, fruiting body formation was enhanced where carbon and nitrogen sources were sufficient. Limitation of C-source caused predominant asexual development while inhibiting sexual development. When higher concentrations of glucose were supplied, more cleistothecia were formed. Other carbon sources including lactose, galactose and glycerol made the fungus develop cleistothecia very well, whereas acetate caused asexual sporulation only. Organic nitrogen sources like casein hydrolysate and glycine, and an increase in nitrate or ammonium concentration also enhanced sexual development. In addition to nutrient effects, low levels of aerobic respiration, caused either by platesealing or treatment with various chemicals, favored sexual development. Carbon limitation, light exposure and a high concentration of salts promoted asexual development preferentially, suggesting that stress conditions may drive the cell to develop asexual sporulation while comfortable and wellnourished growth conditions favored sexual development.

• Laboraroty Animal Research
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• v.34 no.4
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• pp.195-202
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• 2018

Hyperglycemia is one of the major risk factors for stroke. Hyperglycemia can lead to a more extensive infarct volume, aggravate neuronal damage after cerebral ischemia. ${\alpha}$-Synuclein is especially abundant in neuronal tissue, where it underlies the etiopathology of several neurodegenerative diseases. This study investigated whether hyperglycemic conditions regulate the expression of ${\alpha}$-synuclein in middle cerebral artery occlusion (MCAO)-induced cerebral ischemic injury. Male Sprague-Dawley rats were treated with streptozotocin (40 mg/kg) via intraperitoneal injection to induce hyperglycemic conditions. MCAO were performed four weeks after streptozotocin injection to induce focal cerebral ischemia, and cerebral cortex tissues were obtained 24 hours after MCAO. We confirmed that MCAO induced neurological functional deficits and cerebral infarction, and these changes were more extensive in diabetic animals compared to non-diabetic animals. Moreover, we identified a decrease in ${\alpha}$-synuclein after MCAO injury. Diabetic animals showed a more serious decrease in ${\alpha}$-synuclein than non-diabetic animals. Western blot and reverse-transcription PCR analyses confirmed more extensive decreases in ${\alpha}$-synuclein expression in MCAO-injured animals with diabetic condition than these of non-diabetic animals. It is accepted that ${\alpha}$-synuclein modulates neuronal cell death and exerts a neuroprotective effect. Thus, the results of this study suggest that hyperglycemic conditions cause more serious brain damage in ischemic brain injuries by decreasing ${\alpha}$-synuclein expression.

• Journal of Electrochemical Science and Technology
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• v.14 no.4
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• pp.361-368
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• 2023

In lithium-sulfur (Li-S) batteries, encapsulation of sulfur in activated carbon (AC) materials is a promising strategy for preventing the dissolution of lithium polysulfide into electrolytes and enhancing cycle life, because instead of solid-liquid-solid reactions, quasi-solid-state (QSS) reactions occur in the AC micropores. While a high weight fraction of sulfur in S/AC composites is essential for achieving a high energy density of Li-S cells, the deterioration mechanisms under such conditions are still unclear. In this study, we report the deterioration mechanisms during charge-discharge cycling when the discharge products overflow from the AC. Analysis using scanning electron microscopy and energy-dispersive X-ray spectrometry confirms that the sulfur in the S/AC composites migrates outside the AC as cycling progresses, and it is barely present in the AC after 20 cycles, which corresponds to the capacity decay of the cell. Impedance analysis clearly shows that the electrical resistance of the S/AC composite and the charge-transfer resistance of QSS reactions significantly increase as a result of sulfur migration. On the other hand, the charge-discharge cycling performance under limited-capacity conditions, where the discharge products are encapsulated inside the AC, is extremely stable. These results reveal the degradation mechanism of a Li-S cell with micro-porous carbon and provide crucial insights into the design of a S/AC composite cathode and its operating conditions needed to achieve stable cycling performance.

• International Journal of Precision Engineering and Manufacturing
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• v.5 no.4
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• pp.5-13
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• 2004

This study explains the effects of lubricant and surface treatment on the life of hot forging dies. The thermal load and thermal softening, that occur when there is contact between the hotter billet and the cooler dies in hot forging, cause wear, thermal cracking and fatigue, and plastic deformation. Because the cooling effect and low friction are essential to the long life of dies, the proper selection of lubricant and surface treatment is very important in hot forging process. The two main factors that decide friction and heat transfer conditions are lubricant and surface treatment, which are directly related to friction factor and surface heat transfer coefficient. Experiments were performed for obtaining the friction factors and the surface heat transfer coefficients in different lubricants and surface treatments. For lubrication, oil-base and water-base graphite lubricants were used, and ion-nitride and carbon-nitride were used as surface treatment conditions. The methods for estimating die service life that are suggested in this study were applied to a finisher die during the hot forging of an automobile part. The new techniques developed in this study for estimating die service life can be used to develop more feasible ways to improve die service life in the hot forging process.

• Smart Structures and Systems
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• v.30 no.6
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• pp.571-582
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• 2022

Optimal life-cycle management is a challenging issue for deteriorating regional bridges. Due to the complexity of regional bridge structural conditions and a large number of inspection and maintenance actions, decision-makers generally choose traditional passive management strategies. They are less efficiency and cost-effectiveness. This paper suggests a deep reinforcement learning framework employing double-deep Q-networks (DDQNs) to improve the life-cycle management of deteriorating regional bridges to tackle these problems. It could produce optimal maintenance plans considering restrictions to maximize maintenance cost-effectiveness to the greatest extent possible. DDQNs method could handle the problem of the overestimation of Q-values in the Nature DQNs. This study also identifies regional bridge deterioration characteristics and the consequence of scheduled maintenance from years of inspection data. To validate the proposed method, a case study containing hundreds of bridges is used to develop optimal life-cycle management strategies. The optimization solutions recommend fewer replacement actions and prefer preventative repair actions when bridges are damaged or are expected to be damaged. By employing the optimal life-cycle regional maintenance strategies, the conditions of bridges can be controlled to a good level. Compared to the nature DQNs, DDQNs offer an optimized scheme containing fewer low-condition bridges and a more costeffective life-cycle management plan.