• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.359-374
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• 2024

A high-fidelity numerical analysis methodology was proposed for evaluating the fuel rod cladding integrity of a Prototype Gen IV Sodium Fast Reactor (PGSFR) during normal operation and Design basis events (DBEs). The MARS-LMR code, system transient safety analysis code, was applied to analyze the DBEs. The results of the MARS-LMR code were used as boundary condition for a 3D computational fluid dynamics (CFD) analysis. The peak temperatures considering HCFs satisfied the cladding temperature limit. The temperature and pressure distributions were calculated by ANSYS CFX code, and applied to structural analysis. Structural analysis was performed using ANSYS Mechanical code. The seismic reactivity insertion SSE accident among DBEs had the highest peak cladding temperature and the maximum stress, as the value of 87 MPa. The fuel cladding had over 40 % safety margin, and the strain was below the strain limit. Deformation behavior was elucidated for providing relative coordinate data on each active fuel rod center. Bending deformation resulted in a flower shape, and bowing bundle did not interact with the duct of fuel assemblies. Fuel rod maximum expansion was generated with highest stress. Therefore, it was concluded that the fuel rod cladding of the PGSFR has sufficient structural safety margin during DBEs.

• Food Science and Preservation
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• v.31 no.3
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• pp.333-345
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• 2024

This study aims to provide an overview of the research on the chemical composition, nutritional value, biological activities, and potential applications of Camellia oleifera seeds. Camellia oleifera Abel. (Theaceae) is a type of woody plant found in various regions, including China, Japan, India, and Southeast Asia. This plant is highly valued for its cooking oil, as the oil extracted from its seeds contains many unsaturated fatty acids (90%), mainly oleic acid (80%), and various biologically active compounds. Oil derived from C. oleifera seeds has been shown to possess numerous health benefits, such as reducing low-density lipoproteins cholesterol levels, preventing cardiovascular diseases and cancer, and regulating blood pressure. Apart from its oil, the seeds of C. oleifera also contain remarkable biological compounds that offer additional health advantages. Despite these promising attributes, C. oleifera has yet to be widely recognized as a potential source of raw materials for pharmaceutical purposes. This lack of popularity and awareness has hindered further exploration of its pharmaceutical benefits and other uses. Through this article, we hope everyone can better understand this plant and have more practical applications in the future.

• Journal of Web Engineering
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• v.14 no.4
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• pp.741-755
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• 2022

In this study, odor components were analyzed using gas chromatography/mass spectrometry (GC/MS) and solid-phase microextraction (SPME), and odor-active compounds (OACs) were identified using GC-olfactometry (GC-O). Among the volatile compounds identified through GC-O, p-anisaldehyde, limonene, estragole, anethole, and trans-anethole elicit the fennel odor. In particular, trans-anethole showed the highest odor intensity and content. Changes in body weight during the experimental period showed decreasing values of fennel essential oil (FEO)-inhaled groups, with both body fat and visceral fat showing decreased levels. An improvement in the body's lipid metabolism was observed, as indicated by the increased levels of cholesterol and triglycerides and decreased levels of insulin in the FEO-inhaled groups compared to group H. Furthermore, the reduction in systolic blood pressure and pulse through the inhalation of FEO was confirmed. Our results indicated that FEO inhalation affected certain lipid metabolisms and cardiovascular health, which are obesity-related dysfunction indicators. Accordingly, this study can provide basic research data for further research as to protective applications of FEO, as well as their volatile profiles.

• Journal of Korean society of Dental Hygiene
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• v.10 no.4
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• pp.735-744
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• 2010

Objectives : The purpose of this study was to examine the stressors and stress-adaptation patterns of students preparing for the national dental hygiene certification examination. Methods : The subjects in this study were dental hygiene juniors in four selected colleges located in the metropolitan area. After a survey was conducted, the collected data were analyzed. Results : 1. Concerning motivation of choosing the department of dental hygiene, the largest group that accounted for 72.2 percent chose it due to employment prospects. As to satisfaction level with the department, 40.4 percent were satisfied. In relation to employment prospects, 54.1 percent thought the prospects were bright. 2. They got a mean of 3.23 in stressors. To be specific, they felt the most stress due to test anxiety(3.70), followed by leisure insufficiency (3.21), the uncertainty of the future(3.18) and parental pressure(2.64). 3. They got a mean of 2.02 in stress-adaptation method. They got 2.31 and 1.72 in long-term and short-term adaptation respectively, which showed that long-term stress adaptation method were more prevailing than short-term ones. 4. As for the relationship of the stressors, there was positive correlation among all the test anxiety, future uncertainty, leisure insufficiency and parental pressure, and their correlation was statistically significant(p<0.000). 5. Regarding connections between general characteristics and the stressors, whether they spent two years or more for college admission, satisfaction level with the dental hygiene department, employment prospects and health status made significant differences to the stressors (p<0.05), and there were significant gaps in adaptation patterns according to academic standing, satisfaction level with the department and health state(p<0.05). Conclusions : The dental hygiene students were under great pressure since they had to prepare for the national dental hygiene certification examination to become a certified dental hygienist, one of professional health care workers. Therefore stress counseling programs and stress-coping programs should be developed to relieve the stress of dental hygiene students who are going to take the national dental hygiene certification examination. And they should be assisted to stay away from stress and to handle their stress in a more active manner.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.33-41
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• 2020

The landing gear of an aircraft is a device that absorbs and dissipates shock energy transmitted from the ground to the fuselage. Among the landing gears, the semi-active MR damper landing gear is supposed to show high-shock absorption efficiency under various landing conditions and secure the stability when out of control. In the case of the MR damper landing gear using an annular channel rather than orifice, Amesim, a commercial multi-physics program, is considered as more useful than the conventional two-degree-of-freedom model because the damping force generated by the pressure drop through the flow annular path can cause cavitation in the low-pressure chamber of the MR damper with a specific internal structure. In this paper, the main dynamic characteristics of the MR damper landing gear with an annular type flow path structure has been analyzed under the condition of cavitation. Based on the analysis results using Amesim, a design guideline for the MR damper flow path that prevents cavitation has been proposed based on the modification of the arrangement of internal components of the damper. The guideline was verified through a drop simulation.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.4
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• pp.31-37
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• 2017

Recently, there has been substantial interest in flexible and wearable devices whose properties and performances are close to conventional devices on hard substrates. Despite the advancement on flexible devices with organic semiconductors or carbon nanotube films, their performances are limited by the carrier scattering at the molecular to molecular or nanotube-to-nanotube junctions. Here in this study, we demonstrate on the vertical semiconductor crystal array embedded in flexible polymer matrix. Such structures can relieve the strain effectively, thereby accommodating large flexural deformation. To achieve such structure, we first established a low-temperature solution-phase synthesis of single crystalline 3D architectures consisting of epitaxially grown ZnO constituent crystals by position and growth direction controlled growth strategy. The ZnO vertical crystal array was integrated into a piece of polydimethylsiloxane (PDMS) substrate, which was then mechanically detached from the hard substrate to achieve the freestanding ZnO-polymer composite. In addition, the characteristics of transferred ZnO were confirmed by additional structural and photoluminescent measurements. The ZnO vertical crystal array embedded in PDMS was further employed as pressure sensor that exhibited an active response to the external pressure, by piezoelectric effect of ZnO crystal.

• The Journal of Engineering Geology
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• v.3 no.3
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• pp.279-293
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• 1993

In recent yeaes, the collapses of man made structures have been encountered from time to time due to the deformation of the ground in korea. Furthermore, the possibilities of casasters from the ground deformation suCh as landslide and active fault are atrracting our attention to the deformation monitoring. In this study, two-coordinate tilt which was monitored during six months in order to develop tediniques for prevention of disasters from the ground deformation. The two-coordinate tilt which was detected by a tilt-sensor installed in shallow depth on the slope with the sensitivity of 0.0001 arc.sec in every 10 minutes was recorded continously to PC through the interface with 200-m line coonection. The observed digital tilt data. together with the relevant meteorological data were analyzed in reference to engineering application. During the whole observation period of six months, the net tilt is 10.06 arc.sec to the west and 73.88 arc.sec to the south. Consequently the ground has a tilt of 74.56 arc.sec to the direction of $S7.75^{\circ}W$ with average tilting of 0.02 arc.sec/hour. In spite of such fast and large tilting, it is interpreted in view of engineering aspects that the site is much safe from danger, since both East-West and North-South components of tilt converge as time goes by. Two categories of deformational events are recognized ; one is toward the direction of surface slope and the other is to the direction of increased pore pressure. Tiks are acenain to have a close relation with precipitation of rain. The daily variation of two-coordinate tilt is delayed 4.3 hours in average after the variation of atmospheric temperature. A certain correlation between atmospheric pressure and deformation might be revealed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.54-63
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• 2018

In this study, the stability and economic feasibility of a MSE (Mechanically stability earth) wall with a pre-cast concrete pacing panel was investigated for a standard section of highway. Based on the design criteria, the MSE walls of the panel type were designed considering the load conditions of the highway, such as the dead load of the concrete pavement, traffic load, and impact load of the barrier. The length of the ribbed metal strip was arranged at 0.9H according to the height of the MSE walls. Because the length of the reinforcement was set to 0.9H according to the height of the MSE wall, the external stability governed by the shape of the reinforced soil was not affected by the height increase. The factor of safety (FOS) for the bearing capacity was decreased drastically due to the increase in self-weight according to the height of the MSE wall. As a result of examining the internal stability according to the cohesive gravity method, the FOS of pullout was increased and the FOS of fracture was decreased. As the height of the MSEW wall increases, the horizontal earth pressure acting as an active force and the vertical earth pressure acting as a resistance force are increased together, so that the FOS of the pullout is increased. Because the long-term allowable tensile force of the ribbed metal strip is constant, the FOS of the fracture is decreased by only an increase in the horizontal earth pressure according to the height. The panel type MSE wall was more economical than the block type at all heights. Compared to the concrete retaining wall, it has excellent economic efficiency at a height of 5.0 m or more.

• Journal of the Korean Chemical Society
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• v.43 no.5
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• pp.564-577
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• 1999

The purpose of this study is to help an improvement of conceptional learning about the properties of gas based on molecular kinetics for secondary school students and to help an improvement of teaching method for reducing misconceptions regarding the molecular kinetics in gas phase for teachers. The subjects of this study were l00 students of 9th grade and 150 students of 11th grade students. The results showed that students had various misconceptions about the properties of gas. The major misconceptions are as follows. First, the energy is released due to the collision of the molecules, and also the direction of action of pressure is related to the direction of gravity. Second, as molecule is heated, the size of molecule is increased, and the molecule is more active because the number of moIecules is increased. Third, the pressure is reduced because of decreasing the temperature at the higher altitude and the pressure of gas molecuIes is inversely proportional to the collision number of gas molecules. Forth, the numbers of molecules of two different molecules in two same containers differ because the size of molecules differ each other. The results suggest that these problems ought to be addressed in chemistry textbooks and in the classroom teaching of chemistry. If teachers are more aware of students' misconceptions they wilI be better able to remove them.

• Journal of Haehwa Medicine
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• v.9 no.1
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• pp.201-214
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• 2000

Precise and detailed clinical research and evaluation based on objective standards are imperative factors in securing reliability of a clinical test. Built on this principle, this clinical test has been conducted during the period between March 1999 and March 2000 dealing with 31 outpatients treated with ShiHo-GuizhiTang or ShiHo-GuizhiTang modify and ShiHo-GuizhiTang mixed prescriptions at the Sung-bo ORIENTAL MEDICAL CLINIC. A variety of information relating to those patients has been collected and analyzed under such criteria as precise diagnoses and their clinical effectiveness. The analysis was duly based on "The theory of cold syndrome". Then, the 31 patients' individual clinical information was compared one another by breaking down the results into sub-categories including gender, age, disease, main symptom, blood pressure, pulse beats, syndrome of abdomen, treatment period, modify and mixed prescription, and evaluation. The result of this clinical test can be summarized as follows: First, ShiHo-GuizhiTang appears to be more frequently prescribed in the case of female patients than in the case of male patients despite the fact that it does not necessarily need to be applied only to female. In addition, the numbers of prescriptions of ShiHo-GuizhiTang in the two age groups consisting of elementary school children and economically active adults respectively were the highest among other age groups. Second, ShiHo-GuizhiTang proved to be most effective in treatment for respiratory ailments and arthritis. Third, ShiHo-GuizhiTang brought down blood pressure of hypertension patients and at the same time benefited patients with normal or lower-than-normal blood pressure who were vulnerable to diseases due to low disease-resistance. Fourth, ShiHo-GuizhiTang was effective in the case of frequent pulse(rapid pulse) and thereby indicating the fact it carries Taiyang superficies syndrome. 지맥 arises from suppressed immune responses owing to adrenocortical hormones. ShiHo-GuizhiTang controls and revitalizes those suppressed immune systems which stem from slow pulse and, as a consequence of that process, helps them return to normal condition of pulse. Fifth, from the standpoint of syndrome of abdomen, feeling of obstruction in the epigastrium serves as an important standard in the process of diagnosing diseases and evaluating effectiveness of treatments. Sixth, according to the results of the clinical test with the 31 patients, a total of 81 percent of test subjects benefited from the treatment. The figure is the sum of 52 percent of I-class (both main symptom and accompanying symptoms had been eliminated) and 29 percent of II-class (part of main symptom and accompanying symptoms had been eliminated) respectively. All told it is safe to say that ShiHo-GuizhiTang can elect to be a viable clinical treatment. In conclusion, it is estimated that this clinical study has drawn up guidelines for objective diagnostic standards and evaluation on specific treatments' effectiveness. This will lead to more general application of ShiHo-GuizhiTang. On top of that, this study could also provide an opportunity to stress the significance of ShiHo-GuizhiTang and ShiHo-GuizhiTang modify and ShiHo-GuizhiTang mixed prescriptions as an alternative treatment for collagen disease which comes from environmental degradation and pollution.