• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.846-854
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• 2024

FEMAXI-ATF is being developed for fuel performance modeling of SiC cladded UO2 fuel with focuses on modeling pellet-cladding mechanical interactions (PCMI). The code considers probability distributions of mechanical strengths of monolithic SiC (mSiC) and SiC fiber reinforced SiC matrix composite (SiC/SiC), while it models pseudo-ductility of SiC/SiC and propagation of cladding failures across the wall thickness direction in deterministic manner without explicitly modeling cracks based on finite element method in one-dimensional geometry. Some hypothetical BWR power ramp conditions were used to test sensitivities of different model parameters on the analyzed PCMI behavior. The results showed that propagation of the cladding failure could be modeled by appropriately reducing modulus of elasticities of the failed wall element, so that the mechanical load of the failed element could be re-distributed to other intact elements. The probability threshold for determination of the wall element failure did not have large influence on the predicted power at failure when the threshold was varied between 25 % and 75 %. The current study is still limited with respect to mechanistic modeling of SiC failure as it only models the propagation of the cladding wall element failure across the homogeneous continuum wall without considering generations and propagations of cracks.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.10
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• pp.979-988
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• 2012

The 3D structure of GDL for fuel cells was measured using high-resolution X-ray tomography in order to study material transport in the GDL. A computational algorithm has been developed to remove noise in the 3D image and construct 3D elements representing carbon fibers of GDL, which were used for both structural and fluid analyses. Changes in the pore structure of GDL under various compression levels were calculated, and the corresponding volume meshes were generated to evaluate the anisotropic permeability of gas within GDL as a function of compression. Furthermore, the transfer of liquid water and reactant gases was simulated by using the volume of fluid (VOF) and pore-network model (PNM) techniques. In addition, the simulation results of liquid water transport in GDL were validated by analogous experiments to visualize the diffusion of fluid in porous media. Through this research, a procedure for simulating the material transport in deformed GDL has been developed; this will help in optimizing the clamping force of fuel cell stacks as well as in determining the design parameters of GDL, such as thickness and porosity.

• Applied Chemistry for Engineering
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• v.26 no.5
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• pp.598-603
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• 2015

In this study, electrochemical properties of pitch-based activated carbon fibers (ACFs) were investigated by different heat-treatment temperature of the pitch-based ACFs in order to improve the specific capacitance of electric double-layer capacitor (EDLC). The ACFs were prepared by different heat-treatment temperatures of 1050 and $1450^{\circ}C$, after activation with 4 M KOH at $800^{\circ}C$ using stabilized pitch fiber. The specific surface area of prepared ACFs increased from $828m^2/g$ to $987m^2/g$, also the micropore and mesopore volumes of prepared ACFs were increased. These results because pore was produced by desorbing oxygen and hydrogen elements within the ACFs, and pore size was increased by contraction ACFs by heat-treatment process. Because of the porous properties, the specific capacitance was increased from 73 F/g to 119 F/g using cyclic voltammetry with 1 M $H_2SO_4$ at scan rates of 5 mV/s.

• Journal of Nutrition and Health
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• v.25 no.6
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• pp.429-449
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• 1992

The consumption of foods rich in TDF should not be associated with impaired mineral absorp-tion and long-term mineral status. In surveys of populations consuming high amounts of TDF e.g Third World populations and vegetarinas gross deficiencies in mineral nutrition have not been noted. If mineral status is low among these groups it is most likely caused by the inadequacy or imbalance of the diet and not by the TDF. The key word is interaction which should be inte-rpreted in dietary imbalances that produce nut-rient deficiencies. There are no strong data to support the concept that TDF inhibits mineral absorption through a binding chelation mechanism. Limited data sug-gest that positively charged groups on polymers such as chitosan and cholestyramine will decrease iron absorption in humans and animals. Because TDF does not contain positively charged groups future research should be directed at the possible role of protein consumed along with TDF and the combination of effects on mineral nutrition Phytic acid is acknowledged as a potent chela-tor of zinc. However its association with zinc and its propensity to lower Zn bioavaiability may enhance the absorption of other elements notably copper and iron. The importance of interactions among nutrients including TDF will gain addi-tional attention in the scientific community. Soluble and insoluble dietary fiber function di-fferently in the intestine. Insoluble fibers accele-rate movement through the intestine. Soluble die-tary fibers appear to regulated blood concentra-tions of glucose and cholesterol albeit by some unknown mechanism. In creased viscosity produ-ced by the SDF in the intestine may provide an explanation of how this class of polymers affects plasma glucose cholesterol and other nutrients. Employing a double-perfusion technique in the rat we demonstrated that viscosity produced by SDF will delay transfer of zinc into the circulatory system. This delayed absorption should not be interpreted as decreased utilization. A great deal of additional research is required to prove the importance of luminaly viscosity produced by SDF on slowing nutrient absorption or regulating bllod nutrient homeostasis. Increased intake of TDF in the total human diet appears desirable. A dietary intake of 35g/day should not be considered to have a negative effect on mineral absorption. It is important to educate people that an intake of more than 35g TDF/day may cause an imbalance in the diet that can adve-rsely affect mineral utilization. Acknowledgments. Appreciation is given to Dr. George V. Vahouny(deceased) who was intense a great competitor in and out of science and who gave the author inspiration Portions of this work were supported by the University of Missouri Ag-ricultural Station and by a grant from the Univer-rch Support Grant RR 07053 from the National Institutes of Health. Contribution of the Missouri Agriculatural Experiments Station Journal Series No. 10747.

• The Research Journal of the Costume Culture
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• v.21 no.1
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• pp.57-65
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• 2013

With environmental pollution becoming a serious problem, recently there has been increased interest in the environment and health. In addition, the development of materials for environmentally friendly and functional clothing has increased. Environmentally friendly products that use bark fibers of the mulberry(dak) tree are expressed in terms of dak fiber and Hanji yarn. This research analyzed consumer's perceived images of Hanji and Hanji yarn infant clothing. The research results are as follows. Based on analyzing images of Hanji and Hanji yarn, Hanji was categorized into four images that can be described as natural, pure, decorative, and functional, and Hanji yarn infant clothing was categorized into three images that can be described as natural, decorative, and functional. Based on the analysis of well-being elements in subjects' lifestyles, the following four inclinations were found: environmental friendliness, pursuit of novelty, life care, and environmental protection. On this basis, the subjects were categorized into three groups: the trend-pursuing group, the life-care group, and the social responsibility group. Subjects' perceived images of Hanji and Hanji yarn infant clothing were investigated, and these products were found to have a strong image of being Korean, traditional, and natural, while being weakly perceived as comfortable, functional, and practical. Analyzing the correlation between images of Hanji and Hanji yarn infant clothing and lifestyle groups revealed that these products were not perceived differently according to group. This study showed that Hanji and Hanji yarn are terms that are commonly associated with positive clothing material. However, both Hanji and Hanji yarn are perceived negatively in terms of functional image, which is an important factor in clothing material. In addition, even among consumers who pursue a lifestyle based on well-being, the functional image of Hanji yarn was not perceived highly. Hence, it is necessary to further examine the effect of terms such as Hanji and Hanji yarn on consumer choices. Therefore, caution is considered needed when using such terms in the marketing of related products.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1665-1673
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• 2013

Recently, the interest and demand on free formed structure providing aesthetic value as well as functionality has been increasing. Formwork has numerous advantages such as high strength, convenience, accuracy and good quality of surface roughness. Nevertheless, it increases construction cost and period to build complex shapes. For these purpose, deposition construction systems such as Contour Crafting and Concrete Printing have been developed with active collaboration between university and industry by applying the rapid prototyping technology to the construction industry in USA and England. Since there has been no related research in Korea, the possibility of spin-off technology and its fusion cannot be expected. In this paper, design elements including mechanical system and control system related to automatic deposition construction system prototype for constructing a free curved structure without mold are described. As for an appropriate material for the system, fiber reinforced mortar was selected by experiments on compressive strength, fluidity, viscosity and setting time. By performing transfer and extrusion experiments, the possibility of the development of deposition construction system was demonstrated. Based on this research results, it is required to keep the automatic deposition construction system improve and extend it into the new application area in construction industry.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.43-49
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• 2007

Anatomical properties of Kenaf (Hibiscus cannabinus L.) planted in a reclaimed-land of Korea were examined to understand the growth characteristics by an optical and scanning electron microscopy. The samples of kenaf were taken from four positions of the stem (3, 35, 70, 105 cm above from the ground) in four growth periods (July. August, September, October) from seeding planted in the middle of May. Bast fiber, phloem rays, cortex parenchyma cells and sieve tube members were observed in phloem, and vessel elements, fibers and rays in xylem. Solitary and multiple radial pores existed in xylem. The cell types of ray parenchyma in radial section were procumbent, upright, and square. The intervascular pitting showed an alternate type. Xylem proportion, the number of bast fibers and dimension of phloem rays increased with increasing growth period, and decreased with increasing stem height. The proportion of multiseriate rays was higher than that of uniseriate and biseriate rays in xylem with increasing growth period. On the other hand, The proportion of multiseriate rays was lower than that of uniseriate and biseriate rays in xylem with increasing stem height.

• Food Science and Preservation
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• v.19 no.2
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• pp.223-228
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• 2012

The effects of soybean powder and $chungkukjang$ powder on the quality characteristics of bread were investigated. The nutritional elements of the soybean powder, $chungkukjang$ powder and wheat flour differed remarkably. The average crude protein, ash, crude lipid, and fiber of soybean powder and $chungkukjang$ powder were approximately 3, 15, 8 and 5 times higher than those of the wheat flour, respectively. The properties of the dough to which soybean powder and $chungkukjang$ powder were added, i.e., its water absorption (%), development time (min) and stability (min) were measured with a farinograph. The water absorption, and development time of the farinogram increased, but its stability decreased when soybean powder and $chungkukjang$ powder were added to white wheat flour. As long as the mixture rate of soybean powder and $chungkukjang$ powder increased, the loaf volume of the bread declined, but the weight significantly increased. The L value decreased, but the a and b values increased in bread crumb that was made from soybean powder and $chungkukjang$ powder. The white wheat flour to which 10% soybean powder and 5% $chungkukjang$ powder were added had the highest scores in flavor, color, texture, taste, and overall acceptability in the sensory evaluation.

• Composites Research
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• v.34 no.4
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• pp.233-240
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• 2021

VaRI(Vacuum assisted Resin Infusion) process, which is cost effective and suitable for manufacturing large-sized composites, is an OoA(Out-of Autoclave) process. For rapid resin infusion in the VaRI process, a DM(distribution media) is placed on top of the fabric. The resin is rapidly supplied in plane direction of the fiber along the DM, and then the supplied resin is impregnated in the out-of-plane direction of fiber. It is difficult to predict the flow of resin because the flow of in-plane direction and the out-of-plane direction occur together, and a 3D numerical analysis program is used to simulate the resin infusion process. However, in order to analyze in 3D, many elements are required in the out-of-plane direction of fabric. And the product size is larger, the longer the analysis time needs. Therefore, in this study, a method was suggested to reduce the time required for flow analysis by simplifying the 3D flow analysis to 2D flow analysis. The usefulness was verified by comparing the 3D flow analysis with the simplified 2D flow analysis at the same conditions. The filling time error was about 7% and the reduction of flow analysis time was about 95%. In addition, by utilizing the constant difference in the flow front between the top, middle, and bottom of the fabric of the 3D analysis, the flow front of the top, middle, and bottom of the fabric can be also predicted in the 2D flow analysis.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.35 no.4
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• pp.63-74
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• 2022

Objectives : Skin aging is generally characterized by wrinkles, sagging, loss of elasticity roughness, pigmentation and dryness. This changes is caused by reducing the elements constituting the extracellular matrix contributing to the physiological properties of the skin, such as collagen fiber, elastic fiber, and hyaluronic acid. Adequate skin hydration is important to maintain normal skin function and reduce skin aging. The present study is objective to observe skin moisturizing effects of Unripe apple(UA, Immature fruit of Malus pumila Mill) in vivo and its underlying molecular mechanisms. Methods : ICR mice were orally administerd UA(100, 200 and 400mg/kg/day) for 8 weeks, and skin water contents and the expression of transforming growth factor (TGF)-𝛽1, ceramide, hyaluronan and collagen type I(COL1) were measured in dorsal back skin of the mice. Gene expression of hyaluronan synthase(HAS1, HAS2, HAS3), collagen synthase(COL1A1, COL1A2) and TGF-𝛽1 were also determined by realtime RT-PCR. Results : Skin water contents and the expression of TGF-𝛽1, ceramide, COL1 and hyaluronan were significantly increased in UA group(100, 200 and 400mg/kg/day) compared to vehicle control. The mRNA expression of HAS isoform(HAS1, HAS2, HAS3), COL1A1, COL1A2, and TGF-𝛽1 were also significantly increased by UA. Conclusions : UA has skin moisturizing effects and enhancement activities in skin function related components(COL1, hyaluronan, ceramide and TGF-𝛽1). These results suggested that UA can be a developing candidate for developing alternative skin protective agent or functional food ingredient.