본 연구목적은 고등학생의 게임중독에 미치는 부모와의 관계, 스트레 스, 주관적 행복도의 영향력을 검증하는 것이다. 연구의 대상자는 한국방 정환재단이 주관하고 연세대 사회발전연구소에서 시행한 「한국 어린이· 청소년 행복지수」의 2021년 제12차 조사의 고등학교 청소년 2,272명을 연구의 대상자로 정하였다. 고등학생의 게임중독에 미치는 독립변인들의 직접효과 및 간접효과를 확인하기 위해 SPSS 26.0 및 PROCESS Macro를 사용하였다. 첫째, 고등학생의 부모와의 관계는 스트레스에 부 적 영향, 주관적 행복도에 정적 영향, 게임중독에 부적 영향을 주는 것으 로 확인되었다. 둘째, 스트레스는 주관적 행복도에 부적 영향, 게임중독 에 정적 영향을 미치는 것으로 나타났다. 셋째, 주관적 행복도는 게임중 독에 부적 영향을 주는 것이 규명되었다. 넷째, 부모와의 관계와 게임중 독 간의 관계 내에서 스트레스와 주관적 행복도는 부적인 매개효과를 보 였다. 따라서, 본 연구결과는 향후, 청소년들의 게임중독 및 과몰입을 예 방할 수 있는 교육지원 정책 마련 및 프로그램 운영에 도움이 될 것으로 기대된다.

This study was performed to investigate immune changes by comparing the proportion and function of immune cells in the blood under high-temperature period and convalescence temperature period in Holstein dairy cows. The experiment was conducted using Holstein dairy cows of five animals per group (60 ± 20 months old, 175 ± 78 non-day) from the National Institute of Animal Science at high-temperature period (THI: 76 ± 1.2) and convalescence temperature period (THI: 66 ± 1.3). Complete blood count results showed no change in the number of immune cells between groups. In the analysis using Flow Cytometry of PBMCs, no significant differences were observed among B cells, Helper T cells, cytotoxic T cells, and γδ T cells between groups. However, there was an increase in Th17 cells producing IL-17a, while Th1 cells decreased during the convalescence temperature period. The results of gene expression analysis using qRT-PCR in PBMCs revealed an increase in IL-10 during the convalescence temperature period, while a decrease in HSP70 and HSP90 was observed. In conclusion, the increased expression of IL-10 and the decrease in HSP expression suggest the possibility of a weak recovery from heat stress. However, the lack of observed changes in B cells, T cells, and other immune cells indicates incomplete recovery from heat stress during the convalescence temperature period.

This study aimed to investigate the effects of amino acid complex additives, such as protected vitamin C (VC) or detoxified sulfur (DS), on the growth and metabolism of Hanwoo cattle under high-temperature conditions. Accordingly, farms in Temperature-Humidity Index (THI) regions ranging from 78 to 89 for over 100 days were selected. The experimental groups were control, T1 (lysine + methionine + VC, 50 g/head/day), and T2 (lysine + methionine + DS, 50 g/head/day) with 70, 77, and 71 animals each. The range of the THI for 115 days was 78-89, and this occurred in most of the experiment days. The results showed that there was no significant difference in rectal temperature among the groups. The body weight increased to 786.4 and 809.0kg in the T1 and T2 groups, respectively, compared to the control group (p<0.05). Linoleic acid showed a high result of 2.01% in the T1 group compared to the control group (p<0.05). Unsaturated fatty acids were higher at 55.70 and 56.54% in the T1 and T2 groups, respectively, compared to the control group (p<0.05), and the omega 6/3 ratio was reduced to 20.10% (p<0.05). These findings indicate that T1 has a positive impact on growth, meat quality, and fatty acid composition compared to the control group. In conclusion, amino acid complex with VC improved the body weight of Hanwoo steers and the unsaturated fatty acids and essential amino acids of their meat; however, further research is needed to clarify this impact on carcass performance.

Radiant tubes heat exchangers are critical components that facilitate the heat transfer process to steel in an annealing furnace, and it addresses several engineering problems, such as thermal stress and mechanical failure due to long-term thermal cycling, which can significantly affect the longevity of the tubes and maintenance requirements. In this study, we used commercial software (ANSYS) to simulate the thermal stress and deformation of radiant tubes subjected to extreme thermal conditions and pressure loads. We evaluated both thermally induced deformation and creep deformation, which is a time-dependent deformation under constant stress over the long term. The results showed that uneven temperature conditions and pressure loads lead to significant deformation and potential failures. To mitigate these engineering challenges, we also tested several designs that include supporting brackets. This study provides valuable insights for designing radiant tube heat exchangers in annealing furnaces to extend their lifespan and ensure system safety.

살리실산은 식물의 생장 및 발달, 항산화 방어기작, 광합성 작용 그리고 생물적 및 비생물적 스트레스 조건에서 다양한 생리적 기능을 조절하는 물질로 알려져 있다. 본 연구에서는 고온･건조 스트레스 조건에서 살리실산 경엽처리가 고추의 생육, 광합성 특성 및 항산화효소 활성에 미치는 영향을 구명 하고자 하였다. 광합성 특성 측정결과 광합성 속도, 기공전도 도 및 증산 속도가 증가하였고, 3회차 처리에서 가장 높았다. 세포내 MDA와 H2O2 함량은 살리실산 3회차 처리에서 현저 하게 감소하는 경향을 보였다. APX, CAT, POD 및 SOD 활 성이 현저하게 증가하였으며, 무처리 대비 최대 247, 318, 55 및 54% 증가하였다. 고추의 생육 특성은 무처리구와 유의한 차이를 보이지 않았으나, 상품 수량은 15% 정도 증가하였다. 이러한 결과들을 종합해 볼 때, 살리실산의 경엽처리는 고추 의 광합성 특성과 항산화효소 활성을 증진시켜 고온･건조 스트 레스에 의한 피해 경감에 긍정적 효과를 유발함을 확인하였다

For economic and safe management of Spent Nuclear Fuel (SNF), it is very important to maintain the structural integrity of SNF and to keep the fuel undamaged and handleable. The cladding surrounding nuclear fuel must be protected from physical and mechanical deterioration. The structural evaluation of SNF is very complicated and numerically demanding and it is essential to develop a simplified model for the fuel rod. In this study, a simplified model was developed using a new cladding failure criterion. The simplified model was developed considering only the horizontal or lateral static load utilizing the cladding material properties of irradiated Zirclaoy-4, and applicability in horizontal and vertical drop impacts was investigated. When a fuel rod is subject to bending, a very complicated 3D stress state is generated within the vicinity of the pellet–pellet interface. A very localized stress concentration is observed in the area where the edges of the pellets contact the cladding. If the failure strain criteria obtained from the uniaxial tension test or biaxial tube test is applied, failure is predicted at the beginning stage of loading with premature through-thickness stress or strain development. The localized contact stress or strain is self-limiting and is not a good candidate for the cladding failure criteria. In this work, a new cladding failure criterion is proposed, which can account for the localized stress concentration and the through-thickness stress development. The failure of the cladding is determined by the membrane plus bending stress generated through the thickness of the cladding, which can be calculated by a process called stress linearization along the stress classification line. The failure criterion for SNF was selected as the membrane plus bending stress through stress linearization in the cross-sections through the thickness of the cladding. Because the stress concentration in the cladding around the vicinity of the pellet–pellet interface cannot be simulated in a simplified beam model, a stress correction factor is derived through a comparison of the simplified model and detailed model. The applicability of the developed simplified model is checked through horizontal and vertical drop impact simulations. It is shown that the stress correction factor derived considering static bending loading can be effectively applied to the dynamic impact analyses in both horizontal and vertical orientations.

본 연구는 숲체험 활동이 고등학생의 숲에 대한 태도, 심리적 안녕감, 스트레스에 미치는 효과를 검증하기 위해 실행되었다. 연구대상은 화성시 B동에 위치한 고등학교의 학생 26명으로 도시숲 체험에 참가한 실험집단과 학교숲 체험에 참가한 통제집단으로 나누었고, 각 집단은 매주 1회 2시간씩 5회기의 숲체험 프로그램에 참여하였다. 고등학생 들의 정신적 심리적 변화를 관찰하기 위해 숲에 대한 환경태도 척도, 심리적 안녕감 척도, 학업스트레스 척도를 이용해 사전과 사후 설문조사를 하였다. 자료 분석은 SPSS 23.0 프로그램과 Wilcoxon 부호순위검정을 실시하였다. 연구결과 숲체험 활동에 참여한 고등학생의 숲에 대한 태도에는 유의미한 증가가 있었다. 심리적 안녕감은 학교숲에 참가한 집단은 통계적으로 유의한 정도는 아니었으나 증가가 있었고, 도시숲 체험에 참가한 집단은 유의미한 증가가 있어서 숲체험 활동은 고등학생의 심리적 안녕감에 영향을 주었다. 학업스트레스에 있어서는 학교숲 체험에 참가한 집단은 통계적으로 유의한 정도는 아니었으나 감소가 있었고, 도시숲 체험에 참가한 집단은 유의미한 감소가 있어서 숲체험 활동은 고등학생의 학업스트레스에 영향을 주었다.

For the aerospace structural application of high-strength 2xxx series aluminum alloys, stress corrosion cracking(SCC) behavior in aggressive environments needs to be well understood. In this study, the SCC sensitivities of 2024- T62, 2124-T851 and 2050-T84 alloys in a 3.5% NaCl solution are measured using a constant load testing method without polarization and a slow strain rate test(SSRT) method at a strain rate of 10-6 /sec under a cathodic applied potential. When the specimens are exposed to a 3.5% NaCl solution under a constant load for 10 days, the decrease in tensile ductility is negligible for 2124-T851 and 2050-T84 specimens, proving that T8 heat treatment is beneficial in improving the SCC resistance of 2xxx series aluminum alloys. The specimens are also susceptible to SCC in a hydrogen-generating environment at a slow strain rate of 10−6/sec in a 3.5% NaCl solution under a cathodic applied potential. Regardless of the test method, low impurity 2124-T851 and high Cu/Mg ratio 2050-T84 alloys are found to have relatively lower SCC sensitivity than 2024-T62. The SCC behavior of 2xxx series aluminum alloys in the 3.5% NaCl solution is discussed based on fractographic and micrographic observations.

Environmental stresses caused by climate change, such as high temperature, drought and salinity severely impact plant growth and productivity. Among these factors, high temperature stress will become more severe during summer. In this study, we examined physiological and molecular responses of maize plants to high temperature stress during summer. Highest level of H2O2 was observed in maize leaves collected July 26 compared with June 25 and July 12. Results indicated that high temperature stress triggers production of reactive oxygen species (ROS) in maize leaves. In addition, photosynthetic efficiency (Fv/Fm) sharply decreased in leaves with increasing air temperatures during the day in the field. RT-PCR analysis of maize plants exposed to high temperatures of during the day in field revealed increased accumulation of mitochondrial and chloroplastic small heat shock protein (HSP) transcripts. Results demonstrate that Fv/Fm values and organelle-localized small HSP gene could be used as physiological and molecular indicators of plants impacted by environmental stresses.

According to a recent survey of the stress recognition levels felt by teenagers, 34.9% experienced ' sad or frustrated ' levels with their daily lives being disrupted by more than two weeks in a row and it turned out that the older you are, the higher your stress perception levels are.(청소년백서, 2014). Jeju Island has eight regular high schools (27%) among 30 schools. Middle school students in Jeju are experiencing relatively high admission stress compared to other regions in order to enter regular high schools in the level equalization zone. High school students are also experiencing a higher level of academic awareness in college admissions by the academic reports, adding to the academic stress. Appropriate stress for adolescents provides new stimuli, gives motivation and energy, and can lead to the rehabilitation of learning, however, stress builds up when they are unable to deal with it on their own, leading to experiences of physical and psychological maladaptation as well as drug abuse, delinquency, maladjustment, school violence and suspension.

이 연구는 해결중심 집단상담이 일반 고등학교 학생의 스트레스 대처와 자아존중감에 미치는 효과를 알아보고 현장 적용가능성을 탐색하는데 목적이 있다. D광역시 소재 일반 고등학교 학생 16명을 대상으 로 통제집단과 실험집단에 각각 8명씩 무선배치하고 해결중심 집단상담을 주 1회, 회기별로 90분씩, 총 6회기에 걸쳐 진행하였다. 통제집단과 실험집단에 각각 사전, 사후 스트레스 대처능력과 자아존중감 정도 를 측정하고 수집된 자료는 공변량분석(ANCOVA)을 실시하였으며, 참여자의 자기평가 기록지와 면담 및 연구자의 관찰결과를 종합적으로 분석하여 최종 결론을 도출하였다. 연구 결과, 해결중심 집단상담에 참여한 학생들은 통제집단 학생들에 비해 스트레스 대처능력, 자아존중감이 모두 유의하게 향상되었다. 이 연구는 청소년기 신체적 변화는 물론, 입시 경쟁, 진로문제, 교우관계 및 가치관의 혼란 등 다양한 원인으로 인한 스트레스를 경험하고 있는 고등학생들에게 학교 현장에서 단기 해결중심 집단상담을 적용하여 학생들이 자신의 강점을 인식하고 이를 통해 문제를 해결하도록 도와줌으로써 바람직한 스트레스 대처와 자아존중감 향상을 극대화하도록 하는데 의의가 있다.

The purpose of this study is to find and compare the differences in stress level, stressor, and coping style of high school students according to their personality traits. And to identify the personality traits contributing to stress reduction. The results of the study can be used as basic data for reducing the stress of adolescents to improve their academic achievement and maintain mental and physical stability. The questionnaire survey was conducted for 10 days from June 7 to June 16, 2017 for S high school students in Chungbuk Province. The study employed four measuring instruments as Ego-gram, Ok-gram, stressor scale, and stress coping type scale. Individual personality traits were classified into ego-states and ok-states in TA (Transactional Analysis). Stressors are classified into 5 categories (school life, home life, human relationship, myself, environment) and stress coping styles are classified into 4 categories (problem-focused coping, social-support coping, feeling-focused coping, hope-thinking coping) used in the previous studies. The collected data were analyzed using T-test, ANOVA, and multiple regression analysis. As a result, the stress level of high school students showed significant differences according to sex, year, grade, sleeping time, personality traits, and coping styles. Personality traits that contributed to the stress increase were NP, AC, ‘you positive’, ‘i negative’ and personality trait that contributes to stress reduction is ‘you negative.’ Therefore, we can judge that individual personality traits have significant effects on stress level, stressor, and coping style and need to find the effective stress management method suitable for individual personality traits using counseling, repetition training, self-suggestion etc.

본 논문에서는 풍력 블레이드와 같이 세장비가 크고 초기 비틀림이 존재하는 복합재료로 구성된 블레이드에 대한 이차원 단면의 차원축소와 복원관계를 이론적으로 기술하였다. 그리고 VABS 이용한 보의 차원축소모델에 대한 유효성을 검증하기 위해 선행연구 모델을 활용하여 기존 연구결과를 수치적으로 비교하였다. 실물과 가장 가까운 날개 구조물 2차원 형상에 단 면해석을 적용하여 정밀한 단면의 이산화를 수행하고 VABS를 이용하여 블레이드의 특성(질량행렬, 강성행렬)을 포함한 1 차원 보 모델링을 수행하였다. 1차원 보 모델을 통해 세장비가 큰 날개 구조물의 거동을 확인하고 내부하중을 계산하여 단 면위치에서 변형률 복원을 수치적으로 계산하고 이산화된 단면에 수치적으로 매핑하여 시각적으로 확인하고 여유마진을 계 산하였다.

Most of the structural forms in which ETFE film is used are the cushion(pneumatic membrane structures) and tension type(tensile membrane structures), which have been generally accepted to be the most efficient forms. Tensile membrane structures are pulled outward from the exterior to introduce initial stress. And such structures offer the advantage of a natural shape formed by tensile stress and eliminate the need for blast air. Recently, the number of tension type structures is increasing. However, there are problems of creep and relaxation of ETFE films under long-term stresses. In this paper, the stretch fabrication method is proposed for stretching the film into the plastic region during initial tensioning as a way to increase its strength. And its effectiveness is confirmed by investigating experimental and analytical test using ETFE films.