• The Journal of Natural Sciences
• /
• v.1
• /
• pp.33-45
• /
• 1987

$BaCO_3$ 와 다양한 입자크기의 $TiO_2$ 의 고체상태 반응을 산소 ( 혹은 공기 ) 와 이산화탄소 중에서 열중량 분석법 (TG) 과 시차 열분석법 (DTA) 를 이용하여 반응속도론 및 반응기구를 조사하였다. 중간생성물과 최종생성물의 확인은 X-ray 회절 분석법 (XRD) 을 이용하였다. $TiO_2$ 의 반응성은 입자의 크기가 $0.15\mum$이하일 때 현저히 증가하였다. 반응초기에 $BaTiO_3$ 는 반응물의 접촉표면에서 생기기 시작하며 반응의 진행과정은 Jander 에 따라 확산조절과정이 된다. 반응과정에서 BaO-$TiO_2$ 의 상평형도에 기술된 화합물들이 중간물질로써 나타난다. 공기중에서는 상당한 양의 $Ba_2$$TiO_4$ 가 생성되지만 $CO_2$ 의 분위기에서는 약 $1100^{\circ}C$까지 억제된다. 이 온도는 열역학적 계산치인 $1060\pm$ $50^{\circ}C$와 잘 일치하고 있다. 확산과정의 활성화 에너지 값은 공기중에서는 56.4Kcal/mol 이었으며 이산화탄소의 경우에서는 79.6Kacl/mol 이었다.

• Journal of Industrial Convergence
• /
• v.20 no.8
• /
• pp.137-144
• /
• 2022

This study was conducted to provide the basis for psychological management direction of students ahead of their first field practice by grasping the degree of anxiety and confirming the relationship between departments satisfaction and practice expectations. A survey was conducted on dental hygiene students ahead of their first field practice and 135 people were selected as final analysis subjects. Data analysis investigated general characteristics, department satisfaction, field practice expectation and pre-education satisfaction and statistical analysis was conducted through mean(±SD), one-way ANOVA, and multiple linear regression analysis method. As a result, the anxiety level was high in the lower group of performance in the previous semester, and the department satisfaction and pre-education satisfaction were high in the group with low anxiety level. As a result of the correlation analysis, it was found that department satisfaction, field practice expectation, pre-education satisfaction, and anxiety were negatively correlated, and the higher the practice expectation, the lower the anxiety. Therefore, in order to lower the level of anxiety before field practice, it is necessary to come up with measures to increase interventional pre-education, department satisfaction and field practice expectation.

• The Korean Journal of Rheology
• /
• v.9 no.4
• /
• pp.174-182
• /
• 1997

결정성 고분자수지는 가공조건에 의해 결정되는 미세구조의 변화에 따라 최종물성 이 현저히 달라지므로 최종 성형품의 물성을 극대화하기 위해서는 성형가공 중에 필연적으 로 부가되는 열이력 뿐만 아니라 전단이력이 결정화 거동에 미치는 영향을 규명하고 가공조 건의 최적화를 통하여 미세구조를 적절히 제어하는 것이 요구된다. 따라서 본 연구에서 in-situ 상태로 전단유도 결정화거동을 조사할수 있는 rheo-kinetic 실험 방법을 개발하고 결정화 거동에 미치는 열이력과 전단이력의 영향을 규명하고자 하였다. 이를 위해 비교적 결정화 속도가 빠른 폴리 부틸렌 테레프탈레이트 수지를 대상으로 냉각조건, 전단부가시간, 전단속도등을 다양하게 변화시키면서 plate-plate 레오미터로 시간에 따른 전단응력의 변화 를 조사하는 rheo-kinetic 연구를 수행하였다. 아울러 실험 중에 액체 질소로 급냉하여 얻은 시료를 대상으로 등온 및 비등온의 열분석 실험을 수행하고 JMA식과 Hoffman-Lauritzentlr 을 사용하여 분석한 다음, 그 결과를 rheo-kinetic 해석결과와 비교함으로써 결정화 거동에 미치는 전단응력의 영향을 규명하였다. 일정전단속동하에서 수행한 rheo-kinetic 실험결과, 시간에 따른 저난응력의 증가와 용융열이 증가하는 경향이 매우 유사한 거동을 보이므로 전 단응력의 증가는 결정화가 일어남에 기인한 결과임을 확인할수 있었으며 고분자수지가 전단 이력을 받게 되면 분자배향의 결과로 결정화 유도시간이 짧아지고 결정화속도가 증가할 뿐 만 아니라 보다 더 높은 온도에서 결정화가 일어나게 됨을 알수 있었다. 또 결정화 반가기 시간과 Hoffman-Lauritzen 식의 매개변수들이 전단속도, 전단부가시간, 결정화 온도 등의 이력에 무관하게 전단응력에 따라 선형적으로 변하고 있으므로 전단유도 결정화거동은 수지 에 부가되는 전단응력에 직접적인 영향을 받음을 알수 있었다. 이상과같은 전단유도 결정화 거동에 관한 결과를 가공공정상의 열전달 현상과 결합하여 해서하면 성형품 내부의모폴로지 의 예측이 가능하므로 성형품 물성의 극대화 방안의 수립에 이용될수 있을것으로 사료된다.

• The Journal of the Korea Contents Association
• /
• v.20 no.2
• /
• pp.572-580
• /
• 2020

Recently released AI speakers show a pattern of interacting with the user by mainly with voice and simultaneously displaying simple and formal visual feedback through status LED light. This is due to the limitations of the product characteristics of the speaker, which makes it difficult to interact variously, and even such visual feedback is not standardized for each product, and thus does not give a consistent user experience. By maximizing the visual elements that can be expressed through color and abstract movement to assist voice feedback, the product can provide the user with an extended experience that includes not only functional satisfaction but also emotional satisfaction. In this study, after analyzing the interaction methods of the existing AI speakers, we examined the theory of color communication in order to expand the visual feedback effect, and examined the meaning and expression technique of Color Field Painting, an art genre that maximizes the emotional experience by using only color. Through this, the AI speaker's visual communication function was expanded by designing a way to feedback communication status using LED light.

• Journal of the Korea Convergence Society
• /
• v.11 no.7
• /
• pp.97-104
• /
• 2020

The Purpose of this paper was to explore the effect of hearing impairment on HRQOL in Korean elders. We carry out a cross-sectional analysis using nationally representative data from the KNHANES, 2018. A total of 528 elders who had hearing impairment were included. Statistical analysis was performed using SPSS 25.0, χ²-test, t-test, correlation, and regression analysis to confirm the quality of life, and the influencing factors. There were significant differences in HRQOL according to gender, age, education, marital status, income, occupation, number of household members, tinnitus, number of comorbidities, smoking status, alcohol drinking status, subjective health status, regular exercise, restriction of activity, depressive mood and perceived stress. The results indicated that age, BMI and number of comorbidities had a significant negative association with HRQOL. In addition, marital status, number of comorbidities, body mass index, subjective health status, regular exercise, restriction of activity and perceived stress were predictors of life quality in elders with Hearing Impairment and the variable in the health-related quality of life was explained by 37.3%. In order to improve the HRQOL of elders with hearing impairment, multidisciplinary efforts and development of educational programs are required.

• Journal of agricultural medicine and community health
• /
• v.38 no.2
• /
• pp.71-84
• /
• 2013

Objectives: As suicide among the elderly population has been a critical issue in Korea, this study aimed to evaluate correlations of suicidal ideation with protective and risk factors among elderly who reside in a rural community. Methods: A total of 157 elders from Gyeongju city, who had attended senior centers in, were enrolled to answer questionnaires including the Geriatric Depression Scale Short Form-Korea and the Scale for Suicidal Ideation. Data were analyzed using SPSS 18.0K for Windows, and included t-test, Pearson correlation, and a three-step hierarchical multiple regression analyses. Results: Using the hierarchical regression analyses for predicting the elderly's suicidal ideation, male gender and social group variables were entered as predictors in the first step(adjusted $R^2$=0.107, P<0.05). Pain, ADLs, family support variables were not entered in the second step. Depression variable was the only predictor in the third step(adjusted $R^2$=0.384, P<0.001). Conclusions: Although this study confirmed the impact of depression on the suicidal ideation, elderly with risk factors including male gender and social isolation should receive a special attention from community health care professionals.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.593-593
• /
• 2013

나노패턴 제작은 차세대 초고밀도 반도체 메모리기술과 바이오칩 등 나노기술의 핵심 분야로, 나노패턴 구조를 나노-바이오 전자소자 및 반도체 산업분야에 적용할 경우 시장 선점 및 막대한 부가가치 창출 등을 통해 국가경쟁력 강화에 크게 기여할 것으로 기대된다. 하지만 대면적 패턴형성이 어려워 뿐만 아니라 $300^{\circ}$ 이상의 열처리 과정에 의한 생산성이 떨어진다. 또한 나노구조가 잘 이루어진 차원, 표면상태, 결정성, 화학적 조성을 갖도록 하는 합성 및 제조상의 어려움 때문이다. 이에 반해 자기정렬 ITO Dot 형성은 상기 기술한 1차원 나노구조형성을 하는 것에 비하여, 나노구조를 제작하기 위하여 공정이 단순하며, 비용 및 생산성 측면에서 유리 할 것으로 생각된다. 이에 본 연구는 E-beam을 이용하여 형성된 ITO 박막에 HCl solution을 이용하여 자기정렬 ITO Dot 형성 후 n-AlGaInP Vertical LED[VLED] 표면에 nano pillar의 두께에 각기 다르게 형성하였으며, 최종적으로 제작된 VLED의 전기적, 광학적 특성을 조사하였다.

• Proceedings of the KSMRM Conference
• /
• 2003.10a
• /
• pp.35-35
• /
• 2003

목적： 나노 산화철 입자 및 생고분자인 PCL(Polycarprolacton)로 표면 코팅한 T2 MR 조영제를 합성하고 동물 종양 모델을 이용하여 In vivo 특성을 조사하고자 하였다. 대상 및 방법： $FeC1_2$.$4H_2$O와 $FeC1_3$.$6H_2$O을 무게비를 1：2로 정량하여 첨가하고 NaOH 혹은 TMAOH로 pH를 조절한후 PCL를 첨가하여 magnetite가 생성되는 동시에 고분자로서 코팅을 한후 증류수로 여러번 씻어준다. TEM, SEM, DLS 및 IR spectroscopy와 SQUID등을 측정하여 최종 반응물의 입자크기, 자성, 코팅 상태등을 평가하였다. 최소의 입자크기를 형성하는데 필요한 실험 조건을 찾기 위해 반응온도, 코팅할 고분자의 함량, 교반속도별로 실험하여서 최적의 조건을 찾으려 하였다. 토끼의 간에 VX2 암종을 이식한 동물 모델을 이용하여 PCL로 표면 코팅된 나노자성체의 in vivo 영상 특성을 알아보았다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.6
• /
• pp.520-526
• /
• 2020

This study aimed to address the effect of poverty on depression and self-rated health in older adults living alone in Korea. In addition, this study identified the mediating effect of social participation on the poverty-depression and poverty-self-rated health relationships. The researcher conducted a secondary data analysis using the 6th wave of the Korean Longitudinal Study on Aging. The final sample was 1,093 older adults living alone. Using structural equation modeling, standardized coefficients of each path were analyzed. Then, the statistical significance of the mediating effect of social participation was addressed via analyzing direct, indirect, and total effects. Results show that older adults under poverty were more depressed and had a lower level of self-rated health than their counterparts. Moreover, frequent participation in religious gatherings, social gatherings, and leisure activities decreased depression in older adults living alone. Moreover, religious gatherings, social gatherings, and alumni meetings were positively related to self-rated health om older adults living alone. Significant mediating effects appeared in poverty-social gathering-depression, poverty-social gathering-self-rated health, and poverty-alumni meeting-self-rated health relationships. Based on the results, the researcher also discussed implications for social work practice.

• Journal of dental hygiene science
• /
• v.13 no.4
• /
• pp.426-433
• /
• 2013

The objective of this study was to examine whether there is an association of oral health conditions between mothers and their preschool children in Korea. A sample of 823 preschool children and their mothers were selected for this study from the database of the fourth Korean National Health and Nutrition examination Survey. Preschool children were defined as children aged 4, 5, and 6 years old. The subjects were clinically examined for the presence of caries lesions (dft index) and their mother was checked for the presence of dental caries (DMFT index) and periodontal status (CPI). The socio-demographic characteristics and mother's oral health behaviours were considered covariates in this study. Univariate and multivariate analysis was adapted to assess the association of oral health condition between mothers and their preschool children. In univariate analysis, there were significant differences between preschool children's dft index and their mother's age (p=0.005), dental treatment demand for the past one year (p=0.034), and DMFT index (p=0.016). In multivariate analysis, only mother's DMFT index was significantly associated with their children's dft index after adjusting for covariates. In conclusion, the mother's oral health was partly associated with their preschool children's oral health in Korea.