• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.959-965
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• 2024

The High Temperature Test Unit (HTTU) was an experimental set-up to conduct separate and integral effects tests of the Pebble Bed Modular Reactor (PBMR) core. The annular core consisted of a randomly packed bed of uniform spheres. Natural convection tests using both nitrogen and helium, and forced convection tests using nitrogen, were conducted. The maximum material temperature achieved during forced convection testing was 1200 ℃. This paper presents the numerical analysis of the flow and temperature distribution for a forced convection test using 3D CFD as well as a 1D systems-CFD computer code. Several modelling approaches are possible, ranging from a fully explicit to a semi-implicit method that relies on correlations of their associated phenomena. For the comparison between codes, the analysis was performed using a porous media approach, where the conduction and radiative heat transfer were lumped together as an effective thermal conductivity and the convective heat transfer was correlated between the solid and gas phases. The results from both codes were validated against the experimental measurements. Favourable results were obtained, in particular by the systems-CFD code with minimal computational and time requirements.

• Geomechanics and Engineering
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• v.38 no.6
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• pp.621-631
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• 2024

In designing earthquake-resistant structures, we traditionally select dynamic loads based on the recurrence period of earthquakes, using individual seismic records or aligning them with the design spectrum. However, these records often represent isolated waveforms lacking continuity, underscoring the need for a deeper understanding of natural seismic phenomena. The Earth's crustal movement, both before and after a significant earthquake, can trigger a series of both minor and major seismic events. These minor earthquakes, which often occur in short time before or after the major seismic events, prompt a critical reassessment of their potential impact on structural design. In this study, we conducted a detailed tunnel response analysis to assess the impact of both single mainshock and multiple earthquake scenarios (including foreshock-mainshock and mainshock-aftershock sequences). Utilizing numerical analysis, we explored how multiple earthquakes affect tunnel deformation. Our findings reveal that sequential seismic events, even those of moderate magnitude, can exert considerable stress on tunnel lining, resulting in heightened bending stress and permanent displacement. This research highlights a significant insight: current seismic design methodologies, which predominantly focus on the largest seismic intensity, may fail to account for the cumulative impact of smaller, yet frequent, seismic events like foreshocks and aftershocks. Our results demonstrate that dynamic analyses considering only a single mainshock are likely to underestimate the potential damage (i.e., ovaling deformation, failure lining, permanent displacement etc.) when compared to analyses that incorporate multiple earthquake scenarios.

• Biomolecules & Therapeutics
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• v.32 no.5
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• pp.531-539
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• 2024

Sleep is one of the most essential physiological phenomena for maintaining health. Sleep disturbances, such as insomnia, are often accompanied by psychiatric or physical conditions such as impaired attention, anxiety, and stress. Medication used to treat insomnia have concerns about potential side effects with long-term use, so interest in the use of alternative medicine is increasing. In this study, we investigated the hypnotic effects of β-lapachone (β-Lap), a natural naphthoquinone compound, using pentobarbital-induced sleep test, immunohistochemistry, real-time PCR, and western blot in mice. Our results indicated that β-Lap exerts a significant hypnotic effect by showing a decrease in sleep onset latency and an increase in total sleep time in pentobarbital-induced sleep model. The results of c-Fos immunostaining showed that β-Lap decreased neuronal activity in the basal forebrain and lateral hypothalamus, which are wakefulness-promoting brain regions, while increasing in the ventrolateral preoptic nucleus, a sleep-promoting region; all these effects were significantly abolished by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), an adenosine A₁ receptor (A₁R) antagonist. Western blot analysis showed that β-Lap increased extracellular signal-regulated kinase phosphorylation and nuclear factor-kappa B translocation from the cytoplasm to the nucleus; these effects were inhibited by DPCPX. Additionally, β-Lap increased the mRNA levels of A₁R. Taken together, these results suggest that β-Lap exerts hypnotic effects, potentially through A₁R.

• Biomedical Science Letters
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• v.2 no.2
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• pp.211-222
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• 1996

The conceptus which are resulted by mating between two genetically non-identical partners can be considered to be an allograft to the mother science which is not rejected by the mother's immunological attack. The present studies have been, therefore, attempted in order to elucidate the mechanism by which protection of the fete-placental allograft, between the C3H/HeJ female mouse and DBA/2 male mouse occurred. For this purpose, firstly systemic immunity was investigated by measuring T and B lymphocytes subsets. Natural killer cell activity in maternal splenic tissue and by observing the effects of pregnancy serums, progesterone and hCG on immune systems. Secondly, local immunity also investigated by measuring T lymphocytes subsets, natural killer cell activity in lymph nodes draining the uterus. The subsets of Thy-1.2$^+$ cells and L 3T4$^+$ cells decreased slightly while the subsets of Ly2$^+$ cell increased significantly compared with those of the control group beyond the mid-gestational stage. The subsets of B cell gradually in-creased from the mid-gestational stage untill delivery. The natural killer cell activity in the maternal splenic tissue significantly increased during the period of 5th to 8th day of gestation. The natural killer cell activity was significantly suppressed by the pregnancy serums and non-pregnant serums compared with those of serum-free group. The treatment of hCG significantly suppressed natural killer cell activity in the dose dependent manner (1 unit/ml-1000 unit/ml) while pro-gesterone increased the natural killer cell activity at phamarcological dose only. In the lymph nodes draining the uterus, the subsets of Thy-1.2$^+$ cells significantly increased during the period of implantation and L3T4$^+$ cell subsets slightly increased during the mid-gestational stage. The subsets of Ly2$^+$ cell increased significantly during the mid-gestational stage, but decreasing slightly be-fore delivery. The natural killer cell activity was significantly elevated after the implantation period in the lymph nodes draining the uterus. The natural killer cell activity of the lymph nodes draining the uterus was higher than those of splenic tissue during the same periods of gestation. It is therefore, concluded that during the pregnancy, the phenomena which the fete-placental allograft has not been rejected and rather protected from the maternal immunological attack might be due to local immune suppression in fete-maternal interface tissues rather than systemic immune suppression. And the subsets of Thy-1.2$^+$ cells and L3T4$^+$ cells mainly contribute to accepting allograft in early stage of pregnancy, while the subsets of Ly2$^+$ cell and the subsets of B cell increased significantly compared with those of the control group beyond the mid-gestational stage, so their role in systemic immunity and local immunity gradually increased from the mid-gestational stage until delivery.

• Journal of Life Science
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• v.19 no.2
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• pp.163-168
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• 2009

To understand cytotoxic activity of Rubia cordifolia L. (Rubiaceae), which has been used as a traditional oriental medicine, the mechanism underlying cytotoxic effect of its extract on human acute Jurkat T cells was investigated. The methanol extract of roots (3 kg) of R. codifolia was evaporated, dissolved in water, and then extracted by dichloromethane. The substances in the chloroform extract showing the most cytotoxic activity were further purified by a series of preparative HPLC. The extracted active substance (65 mg) was designated as CCH1. When Jurkat T cells were treated with CCH1 at concentration ranging from 0.5 to 2.0 ${\mu}g$/ml, apoptotic phenomena of cells companying several subsequent biochemical reactions such as mitochondria cytochrome c release, activation of casapase-8, -9, and caspase- 3, degradation of PARP and DNA fragmentation occurred via mitochondria-dependent pathway. However, abrogation of apoptosis was observed in an ectopic expression of Bcl-xL, which is a suppressor for mitochondrial cytochrome c release. These results demonstrate that the cytotoxicity of CCH1 against Jurkat T cells is attributable to apoptosis mediated by mitochodria-dependent death-signaling regulated by Bcl-xL. In addition, the CCH1 is more potent to leukemia Jurkat T cell than to human peripheral blood monocyte cells (PBMC).

• Applied Biological Chemistry
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• v.30 no.3
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• pp.201-209
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• 1987

Solutions of food colorants were tested with insoluble drugs (kaolin, active carbon, talc, natural aluminum silicate) for their adsorption phenomena in purified water, gastric and intestinal fluid test solutions, respectively. The adsorption isotherms of kaolin with Red 2 in purified water, and active carbon with Red 2, 3, 40 in the three media, with Yellow 4 in purified water, gastric fluid, with Yellow 5 in intestinal fluid and natural aluminum silicate with Red 3 in purified water, intestinal fluid, with Yellow 4, 5 in purified water followed the Freundlich equation, and those of talc with Red 2, 3, Yellow 5 in the three media, with Red 40 in purified water, gastric fluid, with Yellow 4 in intestinal fluid fitted the Langmuir equation. With decrease of the alcohol content of aqueous solutions, the adsorption of coloring food additives is increased, but it decreased in high temperature. Also the activation energy of adsorption of coloring food additives by active carbon was determined.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.5 no.2
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• pp.237-256
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• 1998

Death and dying of human being is a comprehensive system, and death orientation, the subjective meaning related to every component of the death system is developed throughout life. This study was designed and carried out to identify, describe and classify the orientations of Korean adult towards the death system. In an attempt to measure the subjective meaning of death and dying, unstructured Q-methodology was used. The 65 Q-statements developed by Kim(1994), used by Kim(1994) and Park(1996) were adopted as Q-population and 39 Q-statements were selected by the three researchers for Q-items for this study. Thirty-three P-samples were sampled from P-population of literate Korean men and women, 35 and 55 years of age, lived in urban Korea for the last 10 years. Sortings of the 39 Q-items according to the level of personal agreement, and a forced normal distribution into the 9 levels were carried out by the P-samples. The Z-scores of the Q-sort data were computed, and the principal components factor analysis by PC-QUANL Program were carried out. The demographic, socio-cultural and health-related attributes of the P-samples were descriptively analysed. Eight types of death orientation were identified ; Type I ; 'naturalist'. Six P-samples. Death is a natural phenomena, to be accepted as it is and to follow its natural course. Prefer to be informed of all facts and possibilities concernig the course of dying and death to occur to self. Type II ; 'life-after-life negator'. Three P-samples. Time and process of death is the destiny of each person. Death means 'darkness' and 'end to every thing, the absolute end'. Yet, wish physical integrity at the dying and after death. Type III ; 'life-after-life believer'. Six P-samples. Men are travellers passing by this life bound to the life-after-life. Priority concerns are on the activities to prepare self for the eternal life ahead. Disregard premature and sudden death. Type IV ; 'here-now believer' Five P-samples. Positive regard to the cremation of the body and donation of the organs on death. Regard religious and customary post-motem rituals meaningless. Negate life-after life. Type V; 'believer of rituals'. Five P-samples. Death being accepted as a part of, a natural end to, and destiny of human life. Concerned to ensure a dignified end to personal life and dignified post-mortem rituals. Type VI ; 'Realist'(derived from Type I). Two P-samples. Life and death as universal reality. The abrupt death at golden age at the peak of happiness is favored to avoid inevitable physical and mental distress of self and the family. Agreed to the cremation of the body. Disregard rituals. Type VII : 'Fatalist' (derived from Type II). Five P-samples. Not favored, yet, all man are destined to death, the inevitable end of all living beings. To ensure dignified end by personal consummation, information on one's dying and imminent death are to be shared. Type VIII ; 'reality avoider'(derived from Type III). One P-sample. Negative to longevity, artificial prolongation of, meaningless and distressful life. Highly positive to postmortem organ donation.

• 보존과학연구
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• s.36
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• pp.11-32
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• 2015

The purpose of this study is to analyse the properties of natural mineral pigments used in restoration and conservation of cultural assets. For this study blue-based pigments that are sold in market were selected. The component analysis using by XRF and XRD shows that blue pigment consist of Azurite. And each specimens were evaluated particle size, chromaticity, specific gravity and oil-absorption according to rating system of pigments particle size. Results show that the value of L* increase with the decrease in particle size. The results suggest that the physical properties which is specific gravity, oil-absorption and chromaticity depend on the particle sizes of pigments. When it comes to particle size of pigments decreased by increasing the number of rating system. In addition, the chromaticity related to particle size. The result from this study expects to be used as useful referencing data for conservation and restoration of cultural heritage and understanding phenomena of the properties according to various particle size of Seokcheong pigment.

• Nuclear Engineering and Technology
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• v.27 no.3
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• pp.301-316
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• 1995

experimental and computational studies ore carried out to investigate the natural convection of the single phase flow in a tank with a heated horizontal plate facing downward. This is a simplified model for investigations of the influence of a core melt at the bottom of a reactor vessel on the thermal hydraulic behavior in a oater filled cavity surrounding the vessel. In this case the vessel is simulated by a hexahedron insulated box with a heated plate Horizontally mounted at the bottom of the box. The box with the heated plate is installed in a water filled hexahedron tank. Coolers are immersed in the U-type water volume between the box and the tank. Although the multicomponent flows exist more probably below the heated plate in reality, present study concentrates on the single phase flow in a first step prior to investigating the complicated multicomponent thermal hydraulic phenomena. In the present study, in order to get a better understanding for the natural convection characteristics below the heated plate, the velocity and temperature are measured by LDA(Laser Doppler Anemometry) and thermocouples, respectively. And How fields are visualized by taking pictures of the How region with suspended particles. The results show the occurrence of a very effective circulation of the fluid in the whole How area as the heater and coolers are put into operation. In the remote region below the heated plate the new is nearly stagnant, and a remarkable temperature stratification can be observed with very thin thermal boundary. Analytical predictions using the FLUTAN code show a reasonable matching of the measured velocity fields.

• Journal of Industrial Convergence
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• v.21 no.2
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• pp.133-138
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• 2023

Due to social phenomena such as rapid aging in Korea, nuclear familyization, single marriage, and low birth rate, the number of Companion animals and the number of households with Companion animals are increasing due to the increase in single-person households. In fact, one out of every four households has a pet, and the scale of the industry is expected to reach 6 trillion won in 2027. In particular, in a situation where the Companion animal cosmetics market is in the spotlight amid the diversification of the pet industry, there is a great lack of research on related research and industry development methods. Accordingly, this study attempted to search and analyze academic data, patented technologies, and the latest data related to pet cosmetics and provide them as basic data for the Companion animal cosmetics industry, and the results are as follows. Academic data included verification of the effectiveness of natural materials to improve the skin condition of dogs, analysis of the pet cosmetics industry, and research on ICT-converged pet cosmetics, and the industry was mainly cleaning cosmetics, with pet shampoo launches in Amorepacific, LG Household & Healthcare, and Aekyung. In the patented technology for pets, a patent has been registered for natural product material composition and formulation ratio for skin moisturizing, skin improvement, thinning, and inflammation symptom relief. As a result of this award, it was confirmed that research and development are still insufficient compared to the consumption demand of the pet cosmetics market, and it is believed that industry analysis and development research in related fields should be actively carried out.