• Advances in concrete construction
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• v.14 no.1
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• pp.71-77
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• 2022

Creep phenomenon affects the stability and integrity of concrete structures. An inaccurate prediction of these strains may lead to the appearance of cracks and excessive deflections which may cause in some cases the demolition of structures. In fact, the measured values of these uncontrolled strains appear often to be clearly different and larger than the expected ones. Therefore, an accurate prediction of concrete deformations is a necessity. As a matter of fact, the codified descriptions of this phenomenon are unreliable and don't consider the effect of admixtures. The physical nature of creep is not well understood and almost all creep models are mainly of empirical nature. To overcome this issue, a study of the correlation between different parameters affecting concrete creep is performed and a new model for predicting creep of concrete is elaborated. This new model considers the effect of admixtures, specifically the silica fume, in predicting concrete creep and allows an accurate prediction of this phenomenon. The proposed model is based on the observation of physical behavior of creep phenomenon. It targets at expressing creep compliance in terms of structural and environmental parameters. In fact, the experimental observations show that creep curves follow two kinetic regimes leading to a model called Phenomenological Creep Model. By adequate regressions and substitutions, and according to this model, we can express creep compliance in terms of structural, environmental parameters and admixture types and percentage. The proposed new Phenomenological Creep Model Silica Fume (PCM19SF) calculates accurately creep of concrete by considering the effect of silica fume.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.294-302
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• 2003

Unstable cosmetic active ingredients could be degraded rapidly by chemical and photochemical process. Particularly, some of active ingredients like retinol are known to cause skin irritation when applied on the skin excessively. Therefore, it has become a very important issue to encapsulate cosmetic actives for the stabilization and skin protection. This study was performed in order to prepare a chitosan microcapsule containing liposoluble cosmetic actives and to investigate the stabilization effect of actives when chitosan microcapsule was applied in cosmetic formulation. Chitosan, deacetylated form of chitin, has been of interest in the industrial applications due to its biocompatibility, biodegradability, non-toxicity, antimicrobial activity and also used as a wall material of capsule. Retinol was used as a core material and was stabilized by a wall of chitosan and antioxidants. The chitosan microcapsule containing retinol(CMR) was prepared by using coacervation method and W$_1$/O/W$_2$ emulsification techniques. The CMR has 0.5~10.0 ${\mu}{\textrm}{m}$ size distribution and a long-term stability of more than an year inside the cosmetic formulation(O/W). Remaining retinol percentages at 45$^{\circ}C$ after 8 weeks in the CMR dispersion were 15.6%(pH 4.0), 59.8%(pH 6.0) and 65.0%(pH 6.0 with antioxidant) respectively. Retinol stability when added CMR inside a ONV emulsion was better than that of ONV emulsion added non-capsulated retinol. As a result, remaining retinol at 45$^{\circ}C$ after 8 weeks in O/W emulsion added non-capsulated retinol and O/W emulsion containing CMR was 12.7%, 70.5% respectively. It appeared that chitosan treated microcapsule may be used for a potential encapsulation method of unstable active ingredients.

• Journal of Korean Foot and Ankle Society
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• v.26 no.4
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• pp.183-186
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• 2022

Anterior tibialis ruptures are a rare type of injury related to the foot and ankle. Specifically, chronic and non-traumatic ruptures are related to preexisting chronic tendinopathic conditions and anatomical factors. These ruptures may cause persistent pain and functional impairments if neglected. Chronic tibialis anterior ruptures are frequently diagnosed late because the symptoms are not distinct. In cases with chronic or non-traumatic tibialis anterior tendon ruptures, tendons often become irreparable. Hence, various surgical options have been introduced to address this issue. The current surgical treatment options are as follows: free sliding anterior tibialis graft, extensor hallucis longus tendon transfer, and reconstruction with an allograft tendon. To date, there have been few reports about the reconstruction technique using Z-plasty for irreparable tibialis anterior tendon ruptures. In this report, we present a rare case of the application of the tibialis anterior tendon reconstruction technique using Z-plasty and tenodesis for a middle-aged man with an irreparable avulsion injury rupture. We also present the management plan and prognostic outlook, as well as a subsequent review of the relevant literature.

• Advanced Industrial SCIence
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• v.2 no.3
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• pp.1-7
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• 2023

Recently, it is increasing that a issue of concern about radiation exposure. It affects soil, water, air, crops, etc., and in the long term, environmental pollution and food pollution occur, and it is considered to cause social problems and economic damage. Radiation exposure causes diseases and health problems, but as a method for diagnosing diseases, nuclear medicine tests such as X-ray imaging, CT, and PET-CT are conducted, and radiation isotopes are exposed for the purpose of cancer treatment. A Hungarian case study on radiation in water, particularly drinking water, following the release of radioactive waste from Fukushima, and an examination of the Larsemann Hills area in Antarctica, found that it was within the prescribed radioactivity limits of drinking water recommended by the World Health Organization. We looked at radioprotective agents, focusing on DNA damage, cell and organ damage, and cancer, and also investigated various literatures on ACE inhibitors, antioxidants, and natural substances among restoration materials. Although exposed to radiation in everyday life, the reason why it can be safe is probably because there is a radiation protection material and a recovery material for radiation exposure, so we are trying to find possible materials.

• Korean Journal of Culture and Social Issue
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• v.22 no.4
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• pp.643-674
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• 2016

The purpose of present study is to discover the meaning of the Eogul(억울) which is known as a emotion from perceived unfairness. Even though Eogul has been mentioned as a cause of the Hwabyung in Korean culture there were few studies about it. Researchers designed two studies to provide clear understanding for this concept. In study 1, researchers conducted an open-ended questionnaire for 44 participants to deduce the cultural contexts and the whole experience on Eogul. Data were analyzed with grounded theory, the results were cross-checked by different evaluators. According to the analysis, Eogul is not only the negative feelings from the perceived unfairness, but also the motivations and behaviors to resolve the feelings. Especially, what makes Eogul culture-bounded could be related display rules on expressing emotions. We conducted study 2 to clarify the cultural attributes of Eogul in Korean culture. Variables that explain cultural differences were chosen and 123 participants were surveyed with them including the items developed for measuring Eogul. Cultural meanings and implications of Eogul were discussed with the results.

• Journal of Adhesion and Interface
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• v.24 no.2
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• pp.60-63
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• 2023

The AlGaN/GaN heterostructure has high electron mobility due to the two-dimensional electron gas (2-DEG) layer, and has the characteristic of high breakdown voltage at high temperature due to its wide bandgap, making it a promising candidate for high-power and high-frequency electronic devices. Despite these advantages, there are factors that affect the reliability of various device properties such as current collapse. To address this issue, this paper used metal-organic chemical vapor deposition to continuously deposit AlGaN/GaN heterostructure and SiN passivation layer. Material and electrical properties of GaN HEMTs with/without SiN cap layer were analyzed, and based on the results, low-frequency noise characteristics of GaN HEMTs were measured to analyze the conduction mechanism model and the cause of defects within the channel.

• Journal of the Korea Society of Computer and Information
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• v.28 no.8
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• pp.49-58
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• 2023

Dropouts of students not only cause financial loss to the university, but also have negative impacts on individual students and society together. To resolve this issue, various studies have been conducted to predict student dropout using machine learning. This paper presents a model implemented using DNN (Deep Neural Network) and LGBM (Light Gradient Boosting Machine) to predict dropout of university students and compares their performance. The academic record and grade data collected from 20,050 students at A University, a small and medium-sized 4-year university in Seoul, were used for learning. Among the 140 attributes of the collected data, only the attributes with a correlation coefficient of 0.1 or higher with the attribute indicating dropout were extracted and used for learning. As learning algorithms, DNN (Deep Neural Network) and LightGBM (Light Gradient Boosting Machine) were used. Our experimental results showed that the F1-scores of DNN and LGBM were 0.798 and 0.826, respectively, indicating that LGBM provided 2.5% better prediction performance than DNN.

• Economic and Environmental Geology
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• v.55 no.6
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• pp.617-632
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• 2022

In recent years, environmental pollution and determining the main factors causing this pollution have become an important issue. This study investigates the relationship between the agricultural sector and environmental pollution in Azerbaijan for 1992-2018. The dependent variable in the study is the agricultural greenhouse gas emissions (CO₂ equivalent). Eight variables were selected as explanatory variables: four agricultural inputs and four agricultural macro indicators. Unit root tests, ARDL boundary test, FMOLS, DOLS and CCR long-term estimators, Granger causality analysis, and variance decomposition analyses were used to investigate the effect of these variables on agricultural emissions. The results show that chemical fertilizer consumption, livestock number, and pesticide use positively and statistically significantly affect agricultural emissions from agricultural input variables. In contrast, agricultural energy consumption has a negative and significant effect. From agricultural macro indicator variables, it was found that the crop and animal production index had a positive and significant effect on agricultural emissions. According to the Granger causality test results, it was concluded that there are a causality relationship from chemical fertilizer consumption, livestock number, crop and livestock production index variables towards agricultural emissions. Considering all the results obtained, it is seen that the variables that have the most effect on the increase in agricultural emissions in Azerbaijan are the number of livestock, the consumption of chemical fertilizers, and the use of pesticides, respectively. The results from the research will contribute to the information on agricultural greenhouse gas emissions and will play an enlightening role for policymakers and the general public.

• International Journal of Computer Science & Network Security
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• v.23 no.3
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• pp.193-202
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• 2023

Numerous articles under the study and the examination of heavy metals in human teeth have been published in recent years. The heavy metal poisoning is a widespread issue emerged in toxicology area these days. It has been discovered that long-term exposure to heavy metals typically present in traces, in our everyday meals, drinking water, and in the environment as pollution causes heavy metal poisoning in human beings. Industrial effluents, Coal and Oil, as well as a variety of consumer items, such as cosmetics, can all cause this type of exposure. Teeth, which are often thought of as exoskeleton parts, store heavy metals with a high affinity and represent long-term exposure information. In this study, we have chosen and examined the sections of dentine instead, then examined the entire tooth. We have combined the work done on the examination of heavy metals in human teeth using several instrumental approaches e.g. "Optical Spectroscopic Techniques" to detect elemental profile of human teeth in the current study.

• Journal of the Semiconductor & Display Technology
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• v.22 no.2
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• pp.30-34
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• 2023

Since dishing in the CMP process is a major factor that hinders the uniformity of the semiconductor thin film, many studies have focused this issue to improve the non-uniformity of the film due to dishing. In the metal layer, the dishing mainly occurs in the central part of the metal due to a difference in a selection ratio between the metal and the dielectric, thereby generating a step on the surface of the metal layer. Factors that cause dishing include the shape of the thin film, the chemical reaction of the slurry, thermal deformation, and the rotational speed of the pad and head, and dishing occurs due to complex interactions between them. This study analyzed the stress generated on the metal layer surface in the CMP process using ANSYS software, a commercial structure analysis program. The stress caused by the vertical load applied from the pad was analyzed by changing the area density and line width of the dummy metal. As a result of the analysis, the stress in the active region decreased as the pattern density and line width of the dummy metal increased, and it was verified that it was valid compared with the previous study that studied the dishing according to the dummy pattern density and line width of the metal layer. In conclusion, it was confirmed that there is a relationship between dishing and normal stress.