• Journal of the Korea Convergence Society
• /
• v.11 no.3
• /
• pp.145-152
• /
• 2020

This study investigated the differences in health behaviors of adolescents depending on their sexual experiences. Secondary data analysis was conducted using the data of 61,861 respondents from the 2017 adolescents' health behavior online survey in Korea. Adolescents with sexual experience were typically male, in high school, from a boy's school, had low academic performance, lived apart from their parents, and of either high or low economic status; their health behaviors were characterized by more physical activity, stress, sadness and hopelessness, thought/planned/attempted suicide, drinking, and smoking. Almost half of adolescents with sexual experience (48.9%) did not use contraception. The results of this study are significant and can contribute to the development of sex education programs when considering the characteristics of Korean adolescents and their sexual health.

• Journal of Digital Convergence
• /
• v.19 no.10
• /
• pp.535-543
• /
• 2021

The aim of this study was to evaluate the correlation between senile eye diseases such as age-related macular degeneration (AMD), glaucoma and oral health behaviors. Data from the Seventh Korea National Health and Nutrition Examination Survey (KNHANES VII-2) were used to analyze oral health behaviors according to the presence of AMD and glaucoma. Demographics and oral behaviors were analyzed using the complex chi-square test and complex logistic regression to compare participants with AMD and glaucoma with those without AMD and glaucoma. According to the presence or absence of AMD and glaucoma, there were statistically significant differences in age, education level, oral care product use, and difficulty in speaking variables. The results of this study provide evidence of a significant association in some variables between oral behaviors and senile eye diseases.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.21 no.3
• /
• pp.288-298
• /
• 2001

There has been a growing interest in thick composite materials especially for primary structures. Fiber waviness is one of the manufacturing defects frequently encountered in thick composite structures and affects the mechanical properties such as stiffness and strength significantly. Therefore, nondestructive evaluation technique that can detect fiber waviness of thick composite is very important for the integrity of structures. In this study, efforts were made to understand ultrasonic wave propagation in thick composites with uniform fiber waviness by adopting the ray and plane wave theories. Both theoretical and experimental investigations were conducted to understand the wave propagation in thick composites with uniform fiber waviness. The experiments were conducted on specially fabricated thick composite specimens with various degrees of uniform fiber waviness using the conventional through-transmission method to verify the predicted results. The experimental results showed good agreement with the theoretical predictions.

• Korean Journal of Psychosomatic Medicine
• /
• v.7 no.2
• /
• pp.196-202
• /
• 1999

The purpose of the study was to determine the effect of vitamin B complex on stress-induced immune alteration. 21 medical students participated in the study 4 weeks before an academic examination period(baseline), 2 weeks before the exam period and during the exam period. Among them, 10 subjects were given vitamin B complex for 4 weeks, and 11 were not given vitamin B during the whole period. Cell-mediated immune function was measured by lymphocyte proliferative response to phytohemagglutinin(PHA) and interleukin-2(IL-2) production. Global assessment of recent stress(GARS) scale and symptom checklist-90-revised(SCL-90-R) were used to measure the level of subjective stress and psychopathology. Vitamin group had significantly lower scores of anxiety scale on SCL-90-R than non-vitamin group. No significant differences were found in lymphocyte proliferative response to PHA and IL-2 production between vitamin and non-vitamin groups during each period. There were no significant differences in change of of each of the two immune parameters over time as well as between vitamin and non-vitamin groups. However, lymphocyte proliferative response to PHA was significantly increased over time. In conclusion, it was suggested that vitamin B complex is likely to decrease anxiety level, and that exam stress might enhance lymphocyte proliferation regardless of vitamin B.

• Restorative Dentistry and Endodontics
• /
• v.35 no.2
• /
• pp.134-142
• /
• 2010

The purpose of this study was to evaluate the effect of Er,Cr:YSGG laser irradiation with hypersensitivity mode on microtensile bond strength of composite resin. Twenty extracted permanent molars were randomly assigned to six groups, according to the irradiation of Er,Cr:YSGG laser, adhesive system (Optibond FL or Clearfil SE bond) and application time of etchant (15 sec or 20 sec). Then composite resin was build up on each conditioned surface. The restored teeth were stored in distilled water at room temperature for 24 h and twelve specimens for each group were prepared. All specimens were subjected to microtensile bond strength and the fracture modes were evaluated. Also, the prepared dentin surface and laser irradiated dentin surface were examined under SEM. The results were as follows: 1. The microtensile bond strength of laser irradiated group was lower than that of no laser irradiated group. 2. Regardless of laser irradiation, the microtensile bond strength of Optibond FL was higher than that of Clearfil SE bond. And the microtensile bond strength of 20 sec etching group was higher than that of 15 sec etching group when using Optibond FL. 3. The SEM image of laser irradiated dentin surface showed prominent peritubular dentin, opened dentinal tubules and no smear layer.

• Journal of Korea Entertainment Industry Association
• /
• v.13 no.6
• /
• pp.175-186
• /
• 2019

Purposes: This study aimed to investigate the differences in the prevalence of obesity according to sex and age and self-rated health in adults with metabolic syndrome according to sex, age, and the presence or absence of metabolic syndrome. Methods: The study subjects were 5,674 adults, who completed all three components of the KNHANES VI-2. The subjects were categorized, using life transition periods, into young adults, middle-aged adults, and older adults. Research methods were selected based on the research objectives of the KNHANES VI-2. IBM SPSS 23.0 was used for complex samples cross-tabulation and a complex samples general linear model analysis. Results: Obesity was prevalent in 77.2% of young male adults, 66.2% of middle-aged male, and 52.3% of older male adults with metabolic syndrome, whereas it was prevalent in 72.4% of young female adults, 73.9% of middle-aged female adults, and 64.6% of older female adults with metabolic syndrome. Men had higher self-rated health than women. As age increased, self-rated health status decreased. Those with metabolic syndrome had lower self-rated health status than those without metabolic syndrome. Conclusion: The prevalence of obesity was found to be high in those with metabolic syndrome. This study found that based on sex, men had the highest self-rated health status, and based on age, young adults had the highest self-rated health status, whereas those with metabolic syndrome had low self-rated health status.

• Journal of the Microelectronics and Packaging Society
• /
• v.20 no.4
• /
• pp.17-23
• /
• 2013

As a basic research to develop stretchable electronic packaging technology, CNT-Ag composite pads were formed on top of Cu/Sn chip bumps and flip-chip bonded using anisotropic conductive adhesive. Average contact resistances of the flip-chip joints were measured with respect to bonding pressure and presence of the CNT-Ag composite pads. When Cu/Sn chip bumps with CNT-Ag composite pads were flip-chip bonded to substrate Cu pads at 25MPa or 50 MPa, contact resistance was too high to measure. The specimen processed by flip-chip bonding the Cu/Sn chip bumps with CNT-Ag composite pads to the substrate Cu pads exhibited an average contact resistance of $213m{\Omega}$. On the other hand, the flip-chip specimens processed by bonding Cu/Sn chip bumps without CNT-Ag composite pads to substrate Cu pads at 25MPa, 50MPa, and 100MPa exhibited average contact resistances of $370m{\Omega}$, $372m{\Omega}$, and $112m{\Omega}$, respectively.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.201.1-201.1
• /
• 2015

복합 유무기 혼합물을 사용하여 제작한 유기 쌍안정 메모리 소자는 저전력 소비, 고밀도 저장성, 높은 기계적 유연성, 저렴한 가격, 간단한 공정 과정 등의 장점들로 인하여 메모리 분야에서 많은 관심을 받고 있다. 그래핀 옥사이드층을 활용하여 만든 소자에 관한 연구는 이미 다양하게 진행되고 있으나, CdSe/ZnS 양자점을 활용한 메모리 소자에 관한 연구는 아직 많이 연구되고 있지 않다. 본 연구에서는 CdSe/ZnS 양자점을 그래핀 옥사이드에 내포한 유기 쌍안정 메모리 소자를 제작하여 메모리로써의 활용 가능성과 메커니즘을 확인하였다. Indium-tin-oxide (ITO) 기판을 세척한 후, CdSe/ZnS 양자점을 내포한 그래핀 옥사이드 층을 스핀코팅을 이용하여 1000 rpm, 3000 rpm, 1000 rpm으로 각각 3 s, 40 s, 3 s로 코팅한 후 핫플레이트에서 90oC로 30분 동안 열처리 한다. 이렇게 제작된 소자의 실온에서 전류-전압을 측정한 결과 높은 전도도와 낮은 전도도의 비율이 최대 [10]^3까지 나오는 것을 확인할 수 있었다. 투과전자 현미경 및 X선 광전자 분광법 측정결과 그래핀 옥사이드 층과 그 안에 내포된 양자점들의 유무를 확인할 수 있었다. 내구성을 측정한 결과 소자가 안정적이라는 것을 확인할 수 있었다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.9
• /
• pp.3435-3440
• /
• 2010

Unlike the electric method capable of checking only product defect, the real time optical metrology is suggested for measuring and visualizing vibration with respect to position of surface acoustic wave in RF device. The measuring limits and conditions for surface acoustic wave is given, and the interference and diffraction due to RF signal are analyzed by optical interpretation. A single mode laser and a 105MHz-center-frequency repeater filter were employed for experiments and theoretical analysis. In this paper, the optical metrology providing visual energy distribution and real time inspection for surface acoustic wave is proposed for development of high quality multi-service and multi-frequency RF module.

• Journal of the Korean Electrochemical Society
• /
• v.21 no.4
• /
• pp.80-87
• /
• 2018

Safety issues in Li-ion battery system have been prime concerns, as demands for power supply device applicable to wearable device, electrical vehicles and energy storage system have increased. To solve safety problems, promising strategy is to replace organic liquid electrolyte with non-flammable solid electrolyte, leading to the development of all-solid-state battery. However, relative low conductivity and high resistance from rigid solid-solid interface hinder a wide application of solid electrolyte. Composite electrolytes composed of organic and inorganic parts could be alternative solution, which in turn bring about the increase of conductivity and conformal contact at physically rough interfaces. In our study, composite electrolytes were prepared by combining poly(ethylene oxide)(PEO) and $Li_7La_3Zr_2O_{12}$ (LLZO). The crystallinity, morphology and electrochemical performances were investigated with the control of LLZO contents from 0 wt% to 50 wt%. From the results, it is concluded that optimum content and uniform dispersion of LLZO in polymer matrix are significant to improve overall conductivity of composite electrolyte.