월출산국립공원 내에 위치한 남생이(Mauremys reevesii) 대체서식지에서 사육 중인 남생이 15개체(암컷 6, 수컷 9)를 대상으로 개체 간 구애와 공격 행동을 관찰하여 사회적 상호작용을 알아보고자 하였다. 이를 위하여 2020년 5월 18일부터 2020년 10월 19일까지 연구지역에 CCTV를 설치하여 매주 3일(24시간/일), 총 64일 동안 녹화하였고 시간 당 10분 간격으로 분석하였다. 남생이의 구애행동은 총 884회 관찰되었고 수컷은 체중이 가장 가벼운 암컷(3회)보 다 가장 무거운 암컷(357회)에게 더 많은 빈도의 구애행동을 하였다. 남생이의 공격행동은 총 259회 관찰되었으며 암컷-암컷 간 30회, 수컷-수컷은 81회, 암컷-수컷은 148회 관찰되었다. 이를 바탕으로 파악한 우열관계는 전반적으로 암컷이 수컷보다 더 높게 나타났으며, 몸 크기가 클수록 순위가 높게 나타났다. 본 연구는 국내 최초로 남생이의 구애행동 빈도를 통해 번식가능성이 높은 개체를 확인하고 공격 행동에 따른 우열관계를 파악하였다. 연구결과는 멸종위기에 처한 남생이의 관리 및 보전을 위한 행동학적 기초 자료로 활용될 수 있으며, 남생이의 사회구조를 이해하는 데 도움이 될 것이다.

In this study, we aimed to explore whether eating alone is associated with mental health conditions in Korean adolescents. The data of 2,012 Korean adolescents aged 12-18 years were obtained from the Korea National Health and Nutrition Examination Survey 2015–2019. Participants were classified into three groups based on the frequency of eating alone: none (all meals with others); 1 meal/day alone; and 2 meals/day alone. Mental health conditions were assessed based on stress recognition, depressive symptoms, and suicidal ideation. Multivariable logistic regressions were employed to calculate the adjusted odds ratios (AORs) and 95% confidence intervals (CIs) of poor mental health conditions according to the frequency of eating alone. Adolescents who ate 2 meals/day alone had higher odds of stress recognition (AOR: 2.65, 95% CI: 1.94- 3.63), depressive symptoms (AOR: 2.55, 95% CI: 1.47-4.42), and suicidal ideation (AOR: 2.53, 95% CI: 1.05-6.08) than those who ate all their meals with others. In addition, having breakfast or dinner alone increased the odds of stress recognition. Considering the continuous increase in the social phenomenon of eating alone, nutritional educations are needed to develop adolescents' ability to choose more nutritionally balanced and healthy meals when eating alone.

연구의 목적은 노인의 건강증진 행위가 삶의 만족도에 미치는 영향을 파악하고, 주관적 건강상태가 이 두 변수 사이에서 유의미한 매개변수로 작용하는지 확인하는 것이다. 이를 통해 성공적 노화를 위한 의료 복지서비스 개입전략 수립에 필요한 기초자료를 제공하고자 한다. 이를 위해 <고령화연구패널(KLoSA) 제8차년도(2020년)> 원자료를 사용하였고, 문헌적 고찰을 통해 노인의 건강증진 행위, 주관적 건강상태, 삶의 만족도 사이의 관계를 규명하는 연구모형을 구축하였다. SPSS 25.0, SPSS PROCESS Macro의 Model 4.2 프로그램을 사용하여 인구통계학적 특성에 대한 빈도분석, 기술통계, 상관분석, 위계적 회귀분 석, 부트스트래핑(Bootstrapping)을 실시함으로써 유의성을 검증하였다. 본 연구의 주요 연구결과는 다음 과 같다. 첫째, 노인의 건강증진 행위의 수준이 높을수록 주관적 건강상태가 양호하다. 둘째, 노인의 건강 증진 행위의 수준이 높을수록 삶의 만족도가 더 높다. 셋째, 노인의 주관적 건강상태는 건강증진 행위와 삶의 만족도와의 관계에서 유의미한 매개변수로 작용한다. 본 연구는 이런 연구결과를 바탕으로 노인의 삶의 만족도 향상을 위한 정책적·실천적 함의를 논의하였다.

This study explored how task complexity, writing behaviors (i.e., pausing and revision behaviors), and writing performance (i.e., task completion, coherence and cohesion, language use, and expression and tone) influence and relate to each other. Thirty advanced-level Korean EFL undergraduates completed writing tasks differing in complexity. A combination of keystroke logging and stimulated recall interview was employed. It was found that the simple task group showed a greater number of pauses and revisions related to lower-order writing processes, whereas the complex task group showed longer pauses related to higher-order writing processes. While task complexity had no influence on writing performance, writing behaviors revealed significant relationships with text quality. In the simple task group, pause length and revision were negatively related to writing scores, whereas pause frequency revealed mixed results. In the complex task group, consistent negative relations were found between pausing behaviors and text quality, and fewer revisions were related to better scores in expression and tone.

The low-temperature sinterability of TiO2-CuO systems was investigated using a solid solution of SnO2. Sample powders were prepared through conventional ball milling of mixed raw powders. With the SnO2 content, the compositions of the samples were Ti1-xSnxO2-CuO(2 wt.%) in the range of x  0.08. Compared with the samples without SnO2 addition, the densification was enhanced when the samples were sintered at 900oC. The dominant mass transport mechanism seemed to be grain-boundary diffusion during heat treatment at 900oC, where active grain-boundary diffusion was responsible for the improved densification. The rapid grain growth featured by activated sintering was also obstructed with the addition of SnO2. This suggested that both CuO as an activator and SnO2 dopant synergistically reduced the sintering temperature of TiO2.

The damaged spent fuel rods must be stabilized by encapsulation or dry re-fabrication technologies before geological disposal. For applying the dry re-fabrication technology, we manufactured a vertical type furnace to perform both fuel material recovery from damaged fuel rods by oxidative decladding and sinterability improvement of fuel powder by repetition of oxidative and reaction treatment. A horizontal type furnace provides only a diffusion-controlled reaction resulting in longer reaction time and decreasing amount of powder for oxidation and reduction, whereas a vertical type furnace with a submerged gas distributor gives rapid reaction due to flowing gas-solid contact by fluidization. For observation of fluidization behaviors of uranium oxides at room temperature, fluidized column was prepared with transparent cylindrical tube, pressure transmitter and gas flow meter. Number of size of orifice holes was determined by equations in Fluidization Engineering [D.Kunii, O. Levenspiel]. Before uranium oxide test, as surrogates, WO2 (10.8 g/cm3) and Ta2O5 (8.2 g/cm3) powder similar to density of UO2 (10.96 g/cm3) and U3O8 (8.3 g/cm3), respectively were used to achieve fluidization operation conditions in the region from minimum to expanded fluidization. Fluidization behaviors and pressure drop of powder bed was observed according to operation parameters such as gas velocity, number and size of orifice holes, and powder amount.

The nuclide management technology for separating high-heat generating/high-mobility/long-lived nuclides from high-level wastes based on the chemical reactions is under development. In order to secure the reliability of nuclear non-proliferation and to implement the effective safeguards, it is necessary to consider the safeguards from the conceptual design phase of the novel technologies. However, there was no experience and research on safeguards for the chemical reaction based nuclide management technology. In order to development the available monitoring techniques for the safeguards of nuclide management technology, the possible diversion scenarios were developed and the material flows of major nuclear materials were analyzed according to the various diversion strategies for each unit process in this study. The diversion strategies in this study is limited to the diversion of nuclear materials according to the change of operational parameters (temperature, chemical reagents, pressures, etc). The nuclear material distribution behaviors under the abnormal conditions were analyzed and compared with normal conditions using the HSC Chemistry. The results will be used to determine the proper signals and feasible techniques to monitor the abnormal operations.

Galactosemia is a rare, hereditary metabolic disorder caused by the accumulation of galactose and its metabolites in the body due to a lack of enzymes that convert galactose to glucose. This study aimed to investigate the dietary behaviors and nutritional statuses of patients with galactosemia and to provide basic information on the development of nutrition education programs to improve quality of dietary life. A survey was conducted on 13 parents of (<11 years of age) children with galactosemia and 26 parents of (<11 years of age) children without galactosemia. Mean body mass index was greater for school-age children with galactosemia (18.77 kg/m2) than for corresponding normal children (16.55 kg/m2). Underweight and obesity rates of children with galactosemia were greater than those of children without galactosemia. In addition, children with galactosemia had a higher food neophobia rate and thus consumed less food. Normal children exhibited a greater range of food preferences than those with galactosemia, especially for milk and dairy products (p= .001) and fats and sweets (p= .04). Reliable food databases and appropriate dietary recommendations are required to ensure the proper growth of children with galactosemia.

본 연구는 다중벽 탄소나노튜브(MWCNT)로 보강된 복합재 구조의 동적 해석을 다루었다. Mori-Tanaka 모델을 기반으 로 MWCNT 중량 비율, 패널의 곡률, 그리고 CNT의 임의 배열이 복합재의 동적거동에 미치는 상호작용을 연구하였다. 본 연구 결과는 CNT의 부피함유비율의 변화에 따른 복합재의 유효탄성계수를 예측하는 기존 문헌결과와 비교하여 검증하였다. 수치해 석 예제는 복합재의 동적 특성을 평가함에 있어서 MWCNT 보강의 불규칙한 배열 또는 기울어진 방향으로 배치된 효과에 대한 중요성을 제시하였다.

Acrylonitrile–butadiene–styrene (ABS) terpolymer was compounded with short carbon fiber (CF) and carbon nanotube (CNT) using a micro-extruder followed by the injection molding process. Composite samples were fabricated with loading ratios of 20 wt.% CF and 0.1, 0.5 and 1.0 wt.% of CNT. Mechanical, electrical, thermo-mechanical, thermal, melt-flow, and structural investigations of ABS-based composites were conducted by performing tensile, impact, hardness, and wear tests, conductive atomic force microscopy (AFM), dynamic mechanical analysis (DMA), thermal gravimetric analysis (TGA), melt flow rate test (MFR), scanning electron microscopy (SEM) characterization techniques, respectively. According to mechanical test data of resultant composites including tensile and impact test findings, CNT additions led to the remarkable increase in tensile strength and impact resistance for CF reinforced ABS composites. The formation of synergy between CNT nanoparticles and CF was confirmed by electrical conduction results. The conductive path in ABS/CF composite system was achieved by the incorporation of CNT with different loading levels. SEM micrographs of composites proved that CNT nanoparticles exhibited homogeneous dispersion into ABS matrix for lower loadings.

This study investigated alterations in the health behaviors and eating habits due to the coronavirus disease 2019 (COVID- 19) pandemic. An online survey was administered to 270 university students from September 22, 2021 to October 26, 2021. While the frequency of eating at home had increased during the COVID-19 pandemic compared to before the pandemic, there was a decrease in the frequency of eating out, drinking, and eating vegetables. However, the frequency of eating delivery, takeout, and convenience foods and the utilization of online shopping and delivery apps had considerably increased. In addition, when selecting menus, considerations of health, hygiene, and convenience were more important during the COVID-19 pandemic than before the COVID-19 pandemic. Physical activity more than 3 days a week had decreased, whereas sedentary time showed a proportionate increase. The percentage of people who perceived their health status to be worsening was determined to have increased during the COVID-19 pandemic. To prepare for the era of infectious diseases, future research needs to identify health behaviors and dietary problems by administering surveys that include a large sample size and participants of various ages. Moreover, health promotion and nutrition management plans should be prepared accordingly.

본 연구는 신축이음장치를 설치하지 않고 상부구조와 교대를 일체화하는 무조인트 교량의 거동해석에 대한 것이다. 선행연구에서 는 민감도 해석을 통해 무조인트 교량의 최적 수치해석 모들은 상대오차에 의한 변위 형상의 유사성과 정밀도를 유지하면서 실용적 인 shell 요소 기반 모델이 가장 적합한 것으로 판단하였다. 따라서 본 연구에서는 shell 요소 기반 모델과 solid 요소 모델간의 벽체 깊 이별 거동 분석을 수행하였다. 또한 MIDAS Civil과 ABAQUS를 사용하여 해석 프로그램간 비교를 하였다. 반일체식 교대 교량인 A 교와 B 교의 경우 선형 스프링 조건인 Case 1, +30°C의 경우 지반반력으로 인해 벽체 깊이가 깊어질수록 변위가 감소하였다. -30°C의 경우는 지반반력이 작용하지 않으므로 변위 변화가 미소하였다. 완전일체식 교대 교량인 C 교와 흉벽일체식 교대 교량인 D 교의 경우 말뚝의 저항력으로 인하여 +30°C, -30°C 모두 벽체 깊이가 깊어질수록 변위가 감소하였다. 해석 프로그램간 비교는 Case 1의 경우 상 대오차는 미소하였으나 Case 2의 경우는 차이가 발생하였다. 이는 해석 프로그램에 따른 비선형 스프링의 적용 방식의 차이로 인한 것으로 판단된다.

본 연구는 교회 조직에서 목회자들의 공정성 지각과 이타행위, 인지된 조직지원 등의 관계에 대해 탐색 적으로 분석하였다. 한국기독교장로회 교단 소속의 목회자들의 응답 자료 350부를 분석한 결과 다음의 결과를 얻었다. 첫째, 분배공정성은 이타행위에 부(-)적 영향을 주었으며 인지된 조직지원은 이 영향관계를 완화하는 작용을 했다. 둘째, 절차공정성이 이타행위에 미치는 영향과 상호작용공정성이 이타행위에 미치는 영향은 각 정(+)의 방향이었고, 인지된 조직지원은 각 영향 관계를 강화하는 작용을 하였다. 이 중 분배공정성이 이타행위에 미치는 부(-)적 영향과 조직지원의 완화작용 현상에 대해 직업상의 계약적 고용 관계보다 소명의식이 중시되는 목회자 직업의 특이성을 반영하는 것으로 해석하고 그 이유 를 설명하고자 했다. 즉 목회자가 가지는 소명의식이 작동하고 나아가 배금주의적 분위기가 형성되어 경 제적 교환관계를 배격하는 방향으로 표출된다면 분배공정성과 이타행위의 관계가 부(-)적으로 나타날 수 있다는 추론이 가능해진다. 그러나 이런 분석 결과에 따른 해석은 매우 탐색적이어서 향후 보다 엄격한 분석에 근거한 후속 연구 가 필요하다.

Activated corrosion products deposited on the reactor coolant system in a nuclear power plant should be removed to reduce the radiation exposure to workers. Chemical decontamination processes using organic acids have been widely applied to remove the activated corrosion products. However, they are highly corrosive to the base metal and generate a considerable amount of ion exchange resin waste, which is hard to be treated. In order to resolve this problem, KAERI has been developed a chemical decontamination process using chelate-free inorganic acid, HyBRID (Hydrazine Based Reductive metal Ion Decontamination) process. Especially, the Cyclic SP (Sulfuric acid/Permanganate)- HyBRID process was suggested as the decontamination process for applying to the remove the double oxide layer generated on the reactor coolant system in the pressurized water reactor (PWR). During the Cyclic SP-HyBRID process, the process is continuously applied without discharging or recharging of the decontamination process solution from the primary circuit. Thus, it is necessary to include the removal processes of the decontamination reagents middle of the Cyclic SP-HyBRID process, e.g., ‘Mn removal step’ for removing the permanganate ions and ‘hydrazine decomposition step’ for decomposition of the remaining hydrazine. During these removal processes, the metal ions can also be removed from the process solution. In this study, the behaviors of metals were investigated during the Cyclic SP-HyBRID process. The concentration changes of metal ions in the process solution were analyzed using atomic absorption (AA) spectroscopy. The metal precipitates generated during the process were characterized using X-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR) spectroscopy. From the results of the analysis, it was observed that the metal ions dissolved in the process solution were converted into metal hydroxides and precipitated at the Mn removal process. It was confirmed by equilibrium calculation result that the OH− ions generated at the Mn removal can react with the metal ions and form the metal hydroxides. It is considered that this removal behaviors of the metals can contribute the decontamination performance.

Numerous low-and intermediate level radioactive wastes were generated from the decommissioning processes of nuclear power plants. Radionuclides such as Co and Cs contained in decommissioning wastes should be immobilized to prevent the release of radionuclides from the wastes due to its harmful impacts on ecosystem by high radioactivity and long half-life. Ethylenediaminetetraacetic acid (EDTA) used as decontamination agent can be contained in cement waste during decommissioning process of nuclear power plants. In addition, EDTA can be stably and strongly bound with radionuclides, resulting in the acceleration of the nuclide release from solidified cement matrix. Here, we investigated the effects of EDTA on leaching behaviors of Co and Cs immobilized in the cement specimen. The leaching tests were performed according to the ANS 16.1 “Measurement of the leachability of solidified low-level radioactive wastes by a short-term test procedure”. From the results, an increase in the EDTA content in the cement specimen led to an increase in Co leaching, whereas a decrease in Cs leaching. Leaching of Cs was dominantly controlled by diffusion from the pore space of the cement specimen to the solution. The effective diffusion coefficient and leachability index of nuclide were determined using the diffusion-release models of ANS 16.1. The results of present study can be used in the safety assessment for disposal of the radioactive waste generated by decommissioning of nuclear power plants.

Liquid Bi pool is a candidate electrode for an electrometallurgical process in the molten LiCl-KCl eutectic to treat the spent nuclear fuels from nuclear power plants. The electrochemical behavior of Bi3+ ions and the electrode reaction on liquid Bi pool were investigated with the cyclic voltammetry in an environment with or without BiCl3 in the molten LiCl-KCl eutectic. Experimental results showed that two redox reactions of Bi3+ on inert W electrode and the shift of cathodic peak potentials of Li+ and Bi3+ on liquid Bi pool electrode in molten LiCl-KCl eutectic. It is confirmed that the redox reaction of lithium with respect to the liquid Bi pool electrode would occur in a wide range of potentials in molten LiCl-KCl eutectic. The obtained data will be used to design the electrometallurgical process for treating actinide and lanthanide from the spent nuclear fuels and to understand the electrochemical reactions of actinide and lanthanide at liquid Bi pool electrode in the molten LiCl-KCl eutectic.

This study was conducted to investigate the potential of toy provision for stress reduction, welfare improvement and toy preference in finishing pigs. Toy shape was expected to exert effects on stress related behaviors including fighting, bothering, and feed competition. Three different toy shapes (i.e. square, round, and oval) were given to groups of finishing pigs. A no toy control group was also included. The duration and frequency of abnormal behaviors and use time for toy preference were compared among groups. The duration and frequency of stress related behaviors was higher (p<0.01) among the non-toy-using finishing pigs on 20 minutes and 118 times than 16 minutes and 57 times of toy-using finishing pigs. Toy shape exerted no significant effects, however, toy use displayed a clear ability to reduce stress related behaviors among finishing pigs. Toy use time and shape both displayed no clear effect on the duration of stress related behaviors. These behaviors were most frequently displayed in the afternoons when the finishing pigs become most active, and were not affected by toy shape. Overall, the square shaped toy was used much longer (9.7 hours) and more frequently (566 times) in a 24 hour period by the finishing pigs (p<0.01). In conclusion, providing toys to finishing pigs reduces stress and stress related behaviors. This finding is expected to positively impact welfare and improve finishing pig productivity. Square shaped toys were most preferred by the finishing pigs, therefore adopting toys with square features is recommended.