In this paper analyzed the features of how native Korean speakers (K) and native Vietnamese Korean learners (VKL) organize the Apology conversation, focusing on the functional phase. Based on the discourse analysis, a role play was conducted to collect data. In order to investigate the influence of social variables (social status, intimacy), learners' mother tongues and learners' Korean proficiency, different social variables were given in role-play situations, and learners' Korean proficiency was limited to intermediate and advanced levels. The results of analyzing conversations focusing on ‘Error Checking–Apology-Apology Acceptance’, which is the intermediate phase of Apology conversation, are as follows. First, in the Error Checking Phase, K tended to make indirect or preliminary remarks. In contrast, VKL immediately presented communication purposes, and advanced VKL tended to use indirect speech and additional statement. Second, in the Apology phase, the higher social status the other party has and the lower intimacy the two speakers has, the more passive K were. Interestingly, VKL showed the same pattern. For intermediate-level VKL, it was observed that the dialogue sequences were not completed. Third, in the Apology Acceptance phase, K repeatedly expressed apologies through complex dialogue sequences. However, VKL performed a concise conversation by simple dialogue sequences, and the intermediate-level VKL expressed ‘relief’ and ‘gratitude’.

Currently, many complaints have been filed by local residents on helicopter noise while the law on noise prevention and damage compensation at military airfields and military ranges has been in effect since November 27, 2020. The airfields operated by state agencies are inevitably used to defend the country, defend the country, and protect the lives of the people, but various efforts are needed to minimize noise complaints. In general, helicopters operating in a specific area exhibit different noise frequencies depending on the number or size of wings for each type, takeoff speed, and takeoff altitude. Therefore, by measuring and analyzing noise in the take-off stage of a number of helicopters operating in a specific area, this study aims to present more effective noise prevention measures by analyzing the compliance of each type of helicopter with variables such as take-off speed, take-off altitude, and rise rate. Therefore, the results of this study will be significant in terms of resolving complaints and reducing compensation expenditures of local residents around the airport.

형광 강도 변화를 이용하여 세포막의 위상에 따른 하이드록시부티르산 혼입이 생체막에 미치는 영향을 조사하였다. 구형 인지질 이중층인 소포(vesicle)가 이중 에멀젼 기술을 통해 각 층 단위로 제조되었 다. 소포 내부의 수성에는 아미노나프탈렌트리술폰산디소듐(ANTS)이 캡슐화되었으며, 소광제(quencher) 로 자일렌비스피리디늄브로마이드(DPX)를 소포가 분산된 버퍼에 포함시켰다. 형광 등급은 100% 형광으 로서 DPX가 포함된 완충액의 소포와 0% 형광으로서 ANTS와 DPX의 혼합물이 포함된 완충액의 소포를 고려하여 조정되었다. 소포 용액에 하이드록시부티르산 혼입은 막 구조의 변화를 유도하였으며, 이러한 변 화는 하이드록시부티르산 대 지질의 비율에서 소포의 각 층의 상과 관련이 있는 것으로 관찰된다. 관찰된 결과는 머리 그룹과 꼬리 그룹 모두의 패킹 붕괴에 대한 삼투압 및 체적 효과로 인해 소포의 안정성에 의 존하는 것으로 보인다.

This study introduces the licensing process carried out by the regulatory body for construction and operation of the 2nd phase low level radioactive waste disposal facility in Gyeongju. Also, this study presents the experience and lessons learned from this regulatory review for preparing the license review for the next 3rd phase landfill disposal facility. Korea Radioactive Waste Agency (KORAD) submitted a license application to Nuclear Safety and Security commission (NSSC) on December 24, 2015 to obtain permit for construction and operation of the national engineered shallow land disposal facility at Wolsong, Gyeongju. NSSC and Korea Institute of Nuclear Safety (KINS) started the regulatory review process with an initial docket review of the KORAD application including Safety Analysis Report, Radiological Environmental Report and Safety Administration Rules. After reflecting the results of the docket review, the safety review of revised 10 application documents began on November 29, 2016. Total 856 queries and requests for additional information were elicited by thorough technical review until November 16, 2021. As the Gyeongju and Pohang earthquakes occurred in September 2016 and November 2017, respectively, the seismic design of the disposal facility for vault and underground gallery was enhanced from 0.2 g to 0.3 g and the site safety evaluation including groundwater characteristics was re-investigated due to earthquake-induced fault. Also, post-closure safety assessments related to normal/abnormal/human intrusion scenarios were re-performed for reflecting the results of site and design characteristics. Finally, NSSC decided to grant a license of the 2nd phase low level radioactive waste disposal facility under the Nuclear Safety Laws in July 2022. This study introduces important issues and major improvements in terms of safety during the review process and presents the lessons learned from the experience of regulatory review process.

In the present work, a three-phase AC arc plasma torch system is proposed to separate inorganic radioactive materials from the organic liquid waste. For this purpose, first, assuming the resistance of arc plasma ranges between 0.1 and 0.2 ohm, we designed a three-phase AC arc plasma power supply with the power level of 20 kW. Then, a three phase arc plasma torch consisting of three carbon rods with the diameter of 20 mm was designed and mounted on a cylindrical combustion chamber with the inner diameter of 150 mm. Detail design and basic performance of the plasma system were presented and discussed for application to the treatment of radioactive slurry wastes.

In high-level radioactive waste disposal, a high temperature is generated from the canister containing the waste in the engineered barrier, while groundwater flows into the buffer system from the host rock. The temperature increase and groundwater inflow result in the water phase change and saturation variation. Saturation change is related to the thermal conductivity of buffer material; hence the phase change and saturation strongly interact with the temperature evolution. The complex coupled behavior affects the stability of the whole disposal system, and the security of the repository is critical to human-being life. However, it is difficult to predict the long-term coupled behavior in the disposal system due to the considerable field-test scale, and therefore a numerical simulation is a suitable method having repeatability and cost-effectiveness. DECOVALEX is an international cooperating project for developing numerical methods and models for thermo-hydro-mechanical-chemical (THMC) interaction. DECOVALEX has a four-year cycle with various topics. At the current phase, Task C aims to simulate the full-scale emplacement (FE) experiment performed at Mont Terri underground rock laboratory. Nine research groups are participating in the task, and among them, KAERI simulates the experiment using OGS-FLAC. The simulator combines OpenGeoSys for TH simulation and FLAC3D for M simulation. Through the benchmark simulation, we verified OGS-FLAC for the two-phase flow analysis in the disposal system and finally modeled the FE experiment with a three-dimensional grid. We performed a simple sensitivity analysis to investigate the effect of input parameters on the two-phase flow system and confirmed that the compressibility and permeability affected the flow behavior. We also compared the simulation results to the field data and obtained well-matched results from a series of simulation.

This study reassess safety margin of the current Peak Cladding Temperature (PCT) limit of dry storage in terms of hydrogen migration by predicting axial hydrogen diffusion throughout dry storage with respect to wet storage time and average burnup. Applying the hydride nucleation, growth, and dissolution model, an axial finite difference method code for thermal diffusion of hydrogen in zirconium alloy was developed and validated against past experiments. The developed model has been implemented in GIFT – a nuclear fuel analysis code developed by Seoul National University. Various discharge burnups and wet storage time relevant to spent fuel characteristics of Korea were simulated. The result shows that that the amount of hydrogen migrated towards the axial end during dry storage for reference PWR spent fuel is limited to ~50 wppm. This result demonstrates that the current PCT margin is sufficient in terms of hydrogen migration.

Markov envelope as a theoretical solution of the parabolic wave equation with Markov approximation for the von Kármán type random medium is studied and approximated with the convolution of two probability density functions (pdf) of normal and gamma distributions considering the previous studies on the applications of Radiative Transfer Theory (RTT) and the analysis results of earthquake records. Through the approximation with gamma pdf, the constant shape parameter of 2 was determined regardless of the source distance ro. This finding means that the scattering process has the property of an inhomogeneous single-scattering Poisson process, unlike the previous studies, which resulted in a homogeneous multiple-scattering Poisson process. Approximated Markov envelope can be treated as the normalized mean square (MS) envelope for ground acceleration because of the flat source Fourier spectrum. Based on such characteristics, the path duration is estimated from the approximated MS envelope and compared to the empirical formula derived by Boore and Thompson. The results clearly show that the path duration increases proportionately to ro 1/2-ro 2, and the peak value of the RMS envelope is attenuated by exp (-0.0033ro), excluding the geometrical attenuation. The attenuation slope for ro≤100 km is quite similar to that of effective attenuation for shallow crustal earthquakes, and it may be difficult to distinguish the contribution of intrinsic attenuation from effective attenuation. Slowly varying dispersive delay, also called the medium effect, represented by regular pdf, governs the path duration for the source distance shorter than 100 km. Moreover, the diffraction term, also called the distance effect because of scattering, fully controls the path duration beyond the source distance of 300 km and has a steep gradient compared to the medium effect. Source distance 100-300 km is a transition range of the path duration governing effect from random medium to distance. This means that the scattering may not be the prime cause of peak attenuation and envelope broadening for the source distance of less than 200 km. Furthermore, it is also shown that normal distribution is appropriate for the probability distribution of phase difference, as asserted in the previous studies.

In this study, an Co/Fe coated porcelain using a cobalt and ferrous sulfate was sintered at 1,250 oC. The specimens were investigated by HR-XRD, FE-SEM (EDS), Dilatometer, and UV-vis spectrophotometer. The surface of the porcelain was uniformly fused with the pigment, and white ware and celadon body specimens were densely fused to a certain thickness from the surface. Other new compounds were produced by the chemical reaction of cobalt/ferrous sulfate with the porcelain body during the sintering process. These compounds were identified as cobalt ferrite spinel phases for white ware and white mixed ware, and an andradite phase for the celadon body, and the amorphous phase, respectively. As for the color of the specimens coated with cobalt and ferrous mixed pigments, it was found that the L* value was greatly affected by the white ware, and the a* and b* values were significantly changed in the celadon body. The L* values of the specimens fired with pure white ware, celadon body, and white mix ware were 72.1, 60.92, 82.34, respectively. The C7F3 pigment coated porcelain fired at 1,250 oC had L* values of 39.91, 50.17, and 40.53 for the white ware, celadon body, and white mixed ware, respectively; with a* values of -1.07, -2.04, and -0.19, and at b* values of 0.46 and 6.01, it was found to be 4.03. As a new cobalt ferrite spinel phase was formed, it seemed to have had a great influence on the color change of the ceramic surface.

Magnesium-antimonide is a well-known zintl phase thermoelectric material with low band gap energy, earthabundance and characteristic electron-crystal phonon-glass properties. The nominal composition Mg3.8-xZnxSb2 (0.00 ≤ x ≤ 0.02) was synthesized by controlled melting and subsequent vacuum hot pressing method. To investigate phase development and surface morphology during the process, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were carried out. It should be noted that an additional 16 at. % Mg must be added to the system to compensate for Mg loss during the melting process. This study evaluated the thermoelectric properties of the material in terms of Seebeck coefficient, electrical conductivity and thermal conductivity from the low to high temperature regime. The results demonstrated that substituting Zn at Mg sites increased electrical conductivity without significantly affecting the Seebeck coefficient. The maximal dimensionless figure of merit achieved was 0.30 for x = 0.01 at 855 K which is 30% greater than the intrinsic value. Electronic flow properties were also evaluated and discussed to explain the carrier transport mechanism involved in the thermoelectric properties of this alloy system.

This study introduces the Three-Memory-Model (Cherry, 2019) in education into Maritime Simulator- based training in Sri Lanka and conducts empirical research. In simulator-based education what is disseminated as knowledge during the Briefing, Scenario and Debriefing phases must be transferred from short-term, across working memory to long-term-memory. Working memory gained during the scenario phase, could be encoded into long-term-memory through rehearsal probes. But the number of probes which could be tolerated by the participants of simulator-based training has not undergone empirical investigation. Thus, selecting the Open Sea scenario phase as its setting the research questions aim to identify tolerance limits in the participants for the number of freezes and the number of probes introduced during each freeze. The methodology selects a population of seafarers (n = 60). Through stratified random sampling this population was subdivided based on experience at sea as Group A (n = 30): Mean of 2 years and Group B (n = 30): Mean of 13.6 years of sea experience. The duration of the open sea scenario phase is 35 minutes with freezes at 10-minute intervals. The number of probes were given a range of 7 to. Data analysis utilized SPSS. The highest percentage mean value was obtained for three freezes for the Open Sea scenario phase while two freezes had the next highest percentage mean value. The mean value of the tolerance limits for questions during one freeze is approximately 9 and 6 probes for Group A and B respectively. Citing prior research on working memory, visuo-spatial vs. verbal working memory, reaction time and age this study raises a counter argument against the findings: the self-declared tolerance limits of the number of questions the participants feel comfortable to answer during each freeze. The findings of this research are valuable to maritime Simulator-based instructional designers outside and within Sri Lanka.

본 연구는 영국기상청에서 개발된 지역기후모델 Hadley Centre Global Environmental Model version 3 regional climate model (HadGEM3-RA)로부터 모의된 동아시아 지역의 기온과 강수 결과를 평가하였다. HadGEM3-RA 는 Coordinated Regional climate Downscaling Experiment-East Asia (CORDEX-EA) Phase II 영역에서 15년 (2000- 2014년) 모의되었다. 동아시아 여름 몬순에 의한 HadGEM3-RA 강수대 분포는 Asian Precipitation Highly ResolvedObservational Data Integration Towards Evaluation of water resources (APHRODITE) 자료와 잘 일치한다. 그러나, 동 남아시아 강수는 과대 모의하며 남한에서는 과소 모의한다. 특히 모의된 여름철 강수량과 APHRODITE 강수량은 남한 지역에서 가장 낮은 상관 계수와 가장 큰 오차크기(RMSE)를 보인다. 동아시아 기온 예측은 과소 모의하며 겨울철 오 차가 가장 크다. 남한 기온 예측은 봄 동안 가장 큰 과소 모의 오차를 나타냈다. 국지적 예측성을 평가하기 위하여 서 울기상관측소 ASOS 자료와 비교한 기온과 강수의 시계열은 여름철 강수와 겨울철 기온이 과소 모의하는 공간 평균된 검증 결과와 유사하였다. 특히 여름철 강수량 증가시 과소 모의 오차가 증가하였다. 겨울철 기온은 저온에서는 과소 모 의하나 고온은 과대 모의하는 경향이 나타났다. 극한기후지수 비교 결과는 폭염은 과대 모의하여, 집중호우는 과소 모 의하는 오차가 나타났다. 수평해상도25km로 모의된 HadGEM3-RA는 중규모 대류계와 지형성 강수 예측에서 한계를 보였다. 본 연구는 지역기후모델 예측성 개선을 위한 초기 자료 개선, 해상도 향상, 물리 과정의 개선이 필요함을 지시 한다.

Recently, concern regarding disposal of cellulosic material is growing as cellulose is known to produce complexing agent, isosaccharinic acid (ISA), upon degradation. ISA could enhance mobility of some radionuclides, thus increasing the amount of radionuclide released into the environment. Evaluation on the possible impact of the cellulose degradation would be an important aspect in safety evaluation. In this paper, the maximum safe disposal amount cellulose is evaluated considering the disposal environment of silos of 1st phase disposal facility. The key factor governing the impact of cellulose degradation is pH of disposal environment, as cellulose is known to degrade partially at pH above 12.5, and completely at pH above 13. Thus, disposal environment should be analyzed as to determine the extent of degradation. As silos are constructed with large amount of cement, porewater within concrete walls would be of very high pH. However, for high pH porewater to be released into the pores of crushed rock, which is filling up the silos, lower pH groundwater (commonly pH 7) should flow into the silos through the concrete walls. This causes dilution of the high pH concrete porewater, resulting in a lower pH as the silos are filled, reaching to expected pH of 11.8–12.3, which is below cellulose degradation condition. Thus, cellulose degradation is not expected, but to quantitatively evaluate safe disposal amount of cellulose, partial degradation is assumed. Upon literature review, the most conservative ISA concentration, enhancing radionuclide mobility, is determined to be 1.0×10−4 M and to reach this concentration, cellulose mass equivalent to 6wt% of cement of the repository, is required to be degraded. However, this ratio is derived based on complete degradation of cellulose into ISA, so for partial degradation, degradation ratio and yield ratio of ISA should be considered. Commonly, cellulosic material (e.g. cotton, paper, etc.) has degree of polymerization (DP) between 1,000–2,000, and with this DP, degradation ratio is estimated to be about 10%. Furthermore, yield ratio of ISA is known to be 80%. Considering all these aspects, about 1.79×107 kg of cellulose could be disposed, which if converted into number of drums, considering cellulose content of dry active waste, more than 100,000 drums (200 L) could be disposed with negligible impact on safety. Based on the result, negligible impact of cellulose degradation is expected for safety of 1st phase disposal facility. In future, this study could be used as fundamental data for revising waste acceptance criteria.

In this study, phase-pure titanium dioxide TiO2 ceramics are sintered using standard high-temperature solid-state reaction technique at different temperatures (1,000, 1,100, 1,200, 1,300, 1,400 oC). The effect of sintering temperature on the densification and impedance properties of TiO2 ceramics is investigated. The bulk density and average grain size increase with the increase of sintering temperature. Impedance spectroscopy analysis (complex impedance Z * and complex modulus M *), performed in a broad frequency range from 100 Hz to 10 MHz, indicates that the TiO2 ceramics are dielectrically heterogeneous, consisting of grains and grain boundaries. The complex impedance Z *-plane indicates the resistance of grains of the TiO2 ceramics increases with increasing sintering temperature, while that of grain boundaries develops in the opposing direction. The complex modulus M *-plane shows a grain capacitance that seems to be independent of the sintering temperature, while that of the grain boundaries decreases with increasing sintering temperature. These results suggest that different sintering temperatures have effects on the microstructure, leading to changes in the impedance properties of TiO2 ceramics.