• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.8
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• pp.1102-1107
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• 1993

Microwave dielectric properties of CaTiO3 and CaTiO3-TiO2 ceramics for the composition range between 40 and 50 mol% CaO in CaO-TiO2 binary system were investigated. CaTiO3 ceramics with50 mol% CaO showed the dielectric constant (e,) of 178, the temperature coefficient of resonant frequency(c,) of+1000 ppm/'c and the qualify factor Q of 2760 (f0=2.7 GHz ). Dielectric constant and temperature coefficient of resonant frequency of ceramics with dual phases of CaTiO3 and TiO2 decreased gradually from those of CaTiO3 as the CaO content decreased. Q value and density were found to have minimum at the composition of 47 mol% CaO. The degradation of Q value and density in dual phase ceramics seems to be caused by the large pores at grain boundaries and/or within grains remained after rapid growth of CaTiO3 grains as TiO2 Phase decreased.

• Wind and Structures
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• v.23 no.2
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• pp.127-142
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• 2016

Aerodynamic effects, such as drag force and flow-induced vibration (FIV), on civil engineering structures can be minimized by optimally modifying the structure shape. This work investigates the turbulent wake of a square prism with its faces modified into a sinusoidal wave along the spanwise direction using three-dimensional large eddy simulation (LES) and particle image velocimetry (PIV) techniques at Reynolds number $Re_{Dm}$ = 16,500-22,000, based on the nominal width ($D_m$) of the prism and free-stream velocity ($U_{\infty}$). Two arrangements are considered: (i) the top and bottom faces of the prism are shaped into the sinusoidal waves (termed as WSP-A), and (ii) the front and rear faces are modified into the sinusoidal waves (WSP-B). The sinusoidal waves have a wavelength of $6D_m$ and an amplitude of $0.15D_m$. It has been found that the wavy faces lead to more three-dimensional free shear layers in the near wake than the flat faces (smooth square prism). As a result, the roll-up of shear layers is postponed. Furthermore, the near-wake vortical structures exhibit dominant periodic variations along the spanwise direction; the minimum (i.e., saddle) and maximum (i.e., node) cross-sections of the modified prisms have narrow and wide wakes, respectively. The wake recirculation bubble of the modified prism is wider and longer, compared with its smooth counterpart, thus resulting in a significant drag reduction and fluctuating lift suppression (up to 8.7% and 78.2%, respectively, for the case of WSP-A). Multiple dominant frequencies of vortex shedding, which are distinct from that of the smooth prism, are detected in the near wake of the wavy prisms. The present study may shed light on the understanding of the underlying physical mechanisms of FIV control, in terms of passive modification of the bluff-body shape.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.1
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• pp.25-31
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• 1988

The crude calcium acetate (CCA) was made from egg-shell and acetic acid to use the CCA as a coagulant for Tofu (soy bean curd). Amount of CCA. $CO_2$ and residue made from 5.6g egg-shell (average weight of a egg-shell) and 10% acetic acid(50m1) was 3.8g, $300{\pm}10ml(at\;25^{\circ}$ and 2.1g. respectively. Tofu formable minimum concentration of the CCA was about 0.14% similar to that of $CaCl_2$, $MgCl_2$. Volume, hardness, taste and content f protein and lipid of Tofu by addition of CCA were not significantly different in those of Tofu that magnesium chloride and calcium chloride were used.

• Journal of Korean Academy of Nursing
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• v.16 no.3
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• pp.97-107
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• 1986

This study was about nurse's helping behaviors and the purpose of the study was to find out the nurse's helping behaviors, to identify the nurse's helping behavior level by the nurses personal back-ground and to find out the relationship between the nurse's helping behavior and patient's self-exploration. The subjects, consisting of 192 adults in-patients who had less acute physical problem and 192 registered nurses working on these ward in 3 hospitals in Seoul and 1 hospital in Kang Won province of Korea. The data were collected from Jan. to rob. 1986 through the descriptive responds and self-reported questionaires. The instruments used for this study were Carkhuff's index of communication. Henderson's Irritating Listening Behavior, revised by the Kim(1984) and patient problem understanding scale, patients trust scale on nurse, developed by the Kim(1984). Analysis of the Data was done by use of mean, t-test, F-test and Pearson correlation coefficients. The results of study are summerized as follows; 1. Mean of nurse's helping behavior was 1.84 out of 4. These point were less than 3.0 which means the minimum points as the facilitative helper. 3. There was no significant differences of nurses helping behaviors to the nurse's personal back-ground (p<.05). 3. There were positive rotation between the nurse's helping behaviors and patient's self-exploration behavior (P<0001). In conclusion, 1 may can give some suggestion, according to the study results: 1. The systematic study about nurse's helping behavior is need all over the Korea. 2. Educational program for the facilitative relationship between nurses and patient must be developed, 3. Further detailed analysis methods are need on the independent variables of patient's self-explorations behavior.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.3
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• pp.163-172
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• 2020

Purpose : The purpose of this study was to investigate economic anxiety, self-efficacy, and financial stress levels in middle-aged male and identify factors affecting financial stress and provide baseline data for the development of nursing interventions to reduce financial stress in middle-aged male. Methods : Participants were 91 middle-aged male who live in Seoul and Gyeonggi Province. The data collection period was from April 1, 2020, to May 1. In this study, the questionnaire of economic anxiety, self-efficiency, financial stress was used. The data were analyzed by average, standard deviation, minimum, maximum correlation and regression using SPSS version 21.0. Results : In this study, the financial stress of middle-aged male affected economic anxiety with significant results (β=.628, p<.001). The absolute model's explanatory power was 36.8 % (adjusted R2=.368), indicating that economic anxiety affects financial stress levels in middle-aged male (F=27.151, p<.001). Conclusion : This study shows that economic anxiety affects financial stress. Based on the research results, basic data for the development and application of nursing programs to reduce financial stress were presented in consideration of the economic anxiety of middle-aged males. Therefore, there is a need for mediation to help middle-aged men positively recognize real-life situations and changes in society. Such mediation involves the development and application of educational and counseling programs that can reduce financial stress and economic anxiety in middle-aged men.

• Proceedings of the Korean Society of Food Science and Nutrition Conference
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• 2001.12a
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• pp.69-73
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• 2001

Two opioid peptides, YPLDL and YPLDLF, were isolated from enzymatic digests of spinach ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisCO) and named rubiscolin-5 and -6, respectively. These peptides were selective for delta-receptor and the latter was about 3 times more potent than the former. After oral administration in mice at the dose of 100 mg/kg, rubiscolin-6 showed analgesic activity in tail pinch test. It also stimutated learning performance at the same dose in passive avoidance experiment using step-through apparatus. An immunostimulating peptide, MITLAIPVNKPGR, was isolated from a trypsin digest of soybean protein and named soymetide. Immunostimulating activy of soymetide was mediated by fMLP receptor. Interestingly, after oral administration in rats at a dose of 300 mg/kg (po.), soymetide-4 (MITL) protected alopecia (hair-loss) induced by etoposide, a cancer chemotherapy agent. Stimulation of IL-1 release by the peptide was involved in the mechanism. Ovokinin(2-7), RADHPF, is a vasorelaxing peptide released from ovalbumin by the action of chymotrypsin. It lowered blood pressure of spontaneously hypersensive rats (SHR) after oral administration at a dose of 10 mg/kg. RPLKPW, which was designed by replacing 4 amino acid residues in ovokinin(2-7), exhibited hypotensive activity at a dose of 0.1 mg/kg (po.). This peptides was introduced into 3 homologous sites in soybean beta-conglycinin alpha' subunit by site-directed mutagenesis of the cDNA and expressed in E. coli. The minimum effective dose for hypotensive activity of the genetically modified beta-conglycinin alpha' subunit was 10 mg/kg (po.), which is about 1/200 that of ovalbumin.

• Nuclear Engineering and Technology
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• v.34 no.3
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• pp.187-201
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• 2002

The KN-12 cask is designed to transport 12 PWR spent nuclear fuels and to comply with the requirements of Korea Atomic Energy Act, IAEA Safety Standards Series No.57-1 and US 10 CFR Part 71 for a Type B(U)F package. It provides containment, radiation shielding, structural integrity, criticality control and heat removal for normal transport and hypothetical accident conditions. W.H 14$\times$14, 16$\times$16 and 17$\times$17 fuel assemblies with maximum allowable initial enrichment of 5.0 wt.%, maximum average burn-up of 50,000 MWD/MTU and minimum cooling time of 7 years being used in Korea will be loaded and subsequently transported under dry and wet conditions. A forged cylindrical cask body which constitutes the containment vessel is closed by a cask lid. Polyethylene rods for neutron shielding are arranged in two rows of longitudinal bore holes in the cask body wall. A fuel basket to accommodate up to 12 PWR fuel assemblies provides support of the fuels, control of criticality and a path to dissipate heat. Impact limiters to absorb the impact energy under the hypothetical accident conditions are attacked at the top and at the bottom side of the cask during transport. Handling weight loaded with water is 74.8 tons and transport weight loaded with water with the impact limiters is 84.3 tons. The cask will be licensed in accordance with Korea Atomic Energy Act 3nd fabricated in Korea in accordance with ASME B&PV Code Section 111, Division 3.

• Korean Journal of Materials Research
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• v.27 no.6
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• pp.345-349
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• 2017

The effects of electron beam(EB) irradiation on the electrical and optical properties of InGaZnO(IGZO) thin films fabricated using a sol-gel process were investigated. As the EB dose increased, the electrical characteristic of the IGZO TFTs changed from semiconductor to conductor, and the threshold voltage values shifted to the negative direction. X-ray photoelectron spectroscopy analysis of the O 1s core level showed that the relative area of oxygen vacancies increased from 14.68 to 19.08 % as the EB dose increased from 0 to $1.5{\times}10^{16}electrons/cm^2$. In addition, spectroscopic ellipsometer analysis showed that the optical band gap varied from 3.39 to 3.46 eV with increasing EB dose. From the result of band alignment, it was confirmed that the Fermi level($E_F$) of the sample irradiated with $1.5{\times}10^{16}electrons/cm^2$ was located at the closest position to the conduction band minimum(CBM) due to the increase of electron carrier concentration.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.1970-1978
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• 2021

The aim of this study was to optimize the target, moderator, and collimator (TMC) in a neutron beam generator for the accelerator-based BNCT (A-BNCT) system. The optimization employed the Monte Carlo Neutron and Photon (MCNP) simulation. The optimal geometry for the target was decided as the one with the highest neutron flux among nominates, which were called as angled, rib, and tube in this study. The moderator was optimized in terms of consisting material to produce appropriate neutron energy distribution for the treatment. The optimization of the collimator, which wrapped around the target, was carried out by deciding the material to effectively prevent the leakage radiations. As results, characteristic of the neutron beam from the optimized TMC was compared to the recommendation by the International Atomic Energy Agent (IAEA). The tube type target showed the highest neutron flux among nominates. The optimal material for the moderator and collimator were combination of Fluental (Al₂0₃+AlF₃) with ⁶⁰Ni filter and lead, respectively. The optimized TMC satisfied the IAEA recommendations such as the minimum production rate of epithermal neutrons from thermal neutrons: that was 2.5 times higher. The results can be used as source terms for shielding designs of treatment rooms.

• Structural Engineering and Mechanics
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• v.85 no.1
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• pp.29-53
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• 2023

High-strength shielding concrete against gamma radiation is a priority for many medical and industrial facilities. This paper aimed to investigate the gamma-ray shielding properties of high-strength hematite concrete mixed with silica fume (SF) with nanoparticles of lead dioxide (PbO₂), tungsten oxide (WO₃), and bismuth oxide (Bi₂O₃). The effect of mixing steel fibres with the aforementioned binders was also investigated. The reference mixture was prepared for high-strength concrete (HSCC) containing 100% hematite coarse and fine aggregate. Thirteen mixtures containing 5% SF and nanoparticles of PbO₂, WO₃, and Bi₂O₃ (2%, 5%, and 7% of the cement mass, respectively) were prepared. Steel fibres were added at a volume ratio of 0.28% of the volume of concrete with 5% of nanoparticles. The slump test was conducted to workability of fresh concrete Unit weight water permeability, compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity tests were conducted to assess concrete's engineering properties at 28 days. Gamma-ray radiation of 137Cs emits photons with an energy of 662 keV, and that of 60Co emits two photons with energies of 1173 and 1332 keV were applied on concrete specimens to assess radiation shielding properties. Nanoparticles partially replacing cement reduced slump in workability of fresh concrete. The compressive strength of mixtures, including nanoparticles was shown to be greater, achieving 94.5 MPa for the mixture consisting of 7.5 PbO2. In contrast, the mixture (5PbO₂-F) containing steel fibres achieved the highest values for splitting tensile, flexural strength, and modulus of elasticity (11.71, 15.97, and 42,840 MPa, respectively). High-strength shielded concrete (7.5PbO2) showed the best radiation protection. It also showed the minimum concrete thickness required to prevent the transmission of radiation.