• Proceedings of the KWS Conference
• /
• 2010.05a
• /
• pp.76-76
• /
• 2010

무연솔더 재료를 자동차 전장품에 적용하기 위해서는 고온환경에 대한 내구성 및 진동 인자에 대한 영향을 고려해야한다. 특히, ELV(End of Life Vehicles) 지침이 개정됨에 따라 고온용 무연솔더 재료에 대한 재평가가 반드시 필요한 시점이다. 이에 대해 본연구에서는 현재 상용화 된 Pb-free솔더의 재료들 중 총 4종의 Solder을 선정하여 자동차 환경에 부합하는 진동조건하에서 시험해보았다. 그리고 미세조직의 특성, 접합부 형성시의 기계적 강도 및 접합부의 신뢰성을 평가하여 보았다. 각각의 조성에 대한 CHIP type과 QFP type의 실장부품을 준비하였으며, 각각의 조성별로 솔더 페이스트로 Daisy Chain PCB에 접합하여 조성에 따른 비교 데이터를 구축할 수 있었다. 리플로우 공정후 초기의 미세조직 및 전당강도, 저항값을 측정하여 진동시험에 따른 데이터와 비교하였다. 주파수는 10Hz~1,000Hz였으며, 진동가속도는 $29.4m/s^2$, 20시간의 랜덤진동이 적용되는 동안 챔버내의 온도는 상온으로 유지되었다. 진동시험과 이에 따른 저항측정을 통하여 진동 주파수와 시간에 따른 실장 부품이 받는 진동 영향과 실시간 저항값을 측정하였으며, 이때의 미세조직 비교를 통해 진동특성을 평가하였다. 진동 주파수에 따른 저항값의 변화가 있었으며, 진동전후 전단강도에도 영향을 주었다. QFP type에서는 SAC105가 진동에 가장 취약하였으며, CHIP type에서는 SACX0307이 진동에 가장 취약하였다.

• Clinical and Experimental Reproductive Medicine
• /
• v.35 no.4
• /
• pp.275-283
• /
• 2008

Objective: This study was conducted to investigate the effects of the artificial shrinkage and assisted hatching (PZD; patial zona dissetion) before vitrification on the development of vitrified mouse expanding blastocyst. Methods: Mouse 2-cell embryos were collected and cultured in G1.1 and G2.2 to expanding blastocyst. For artificial shrinkage (AS) the micro injection pipette was inserted into blastocoele cavity and blastocoele fluid was aspirated. For assisted hatching (AH) PZD method was used. Control group was -AS/-AH and treatment groups were -AS/+AH, +AS/-AH and +AS/+AH. After AS and AH mouse blastocysts were equillibrated in G10 and G10E20 for 3 mins, respectively, and vitrified in G25E25 after loading on capped pulled-straw. Vitrified mouse blastocysts were thawed and cultured for 24 hrs. The survival and hatching rate was compared among one control and three treatment groups. Results: The survival rates were 99%, 92% in +AS/+AH and +AS/-AH groups and 54%, 58% in -AS/-AH and -AS/+AH group, respectively. The survival rate was significantly higher in +AS group than in -AS group (p<0.01). Hatching rates were 34%, 96% in -AS/-AH and -AS/+AH groups and 41%, 100% in +AS/-AH and +AS/+AH, respectively. The hatching rates was higher in +AH group than in -AH group (p<0.01). After thawing recovery rates were 100%. Loading on capped pulled-straw, that is effective and useful method on vitrification. Conclusion: This study showed that artificial shrinkage of blastocoele cavity and assisted hatching (PZD) significantly improved the development of the vitrified mouse expanding blastocysts.

• Journal of Science Education
• /
• v.47 no.3
• /
• pp.238-250
• /
• 2023

This study aims to explore the effect of an appropriate technology program related to water acquisition and purification on scientific attitudes and creative problem-solving skills in elementary school students. Thus, this study developed a learning program related to the appropriate technology composed of 8 sessions, and some were for exploring water acquisition-related scientific principles and the appropriated technology of Warka Tower, and the others were for conducting water purification-related inquiry experiments, such as Life Straw and Drinkable Book, and the last two sessions were for presenting practical tasks through creative ideas and designs and carrying out the relevant campaign activities. For research subjects, this study selected 51 students from two sixth-grade classes, and after modifying the scientific attitude questionnaire and the creative problem-solving skill questionnaire fit for the environment and situation, this study conducted a paired-sample t-test by applying both the questionnaires before and after this program. In addition, while looking into the correlation between scientific attitudes and creative problem-solving skills, based on the post-test results, this study examined relationships between sub-domains perceived by the students after this program was applied. The results can be summarized as below. Out of all the scientific attitudes, curiosity, openness, cooperation, and creativity showed statistically significant results with an increase in the average value when their overall averages of the pre-test were compared with those of the post-test. With creative problem-solving skills, the domain of mastering a specific area and the domain of divergent thinking showed statistically significant results. The correlation analysis results showed that cooperation out of the scientific attitudes had a significant correlation with all the domains of creative problem-solving skills, especially showing the highest correlation coefficient with such sub-domains as critical and logical thinking. All the four domains of creative problem-solving skills showed a number of significant correlations with the sub-domains of scientific attitudes. Through the research results above, this study has several implications on how and where to apply such appropriate technology-related topics in the future and various responses from students.

• Cartoon and Animation Studies
• /
• s.39
• /
• pp.215-231
• /
• 2015

The Cultural Revolution in the history of Chinese animation hinder the development of the initial animation, and after a negative assessment instrument provided the cause is to become sluggish growth of the Chinese animation. So this time animation are things that are the subject of academic research studies or analysis has been depreciating almost uniformly without evaluation. However, of all the cultural and artistic creation it is developing in its own specific historical conditions and has the aesthetic results. This paper puts the primary purpose is to hold in consideration the aesthetic principles that led to cultural and artistic creativity and objective perspective the achievements the Chinese animation of the time period of the Cultural Revolution. Cultural Revolution is avoided to the previous period in accordance with the socialist ideology of Mao Ze-dong(毛澤東) sikindaneun highlight the culture of the proletariat and placed our goal to create a new class culture. Therefore, cultural and artistic creation of this period is often inconsistent with this part of our aesthetic principles generally accepted character has a non- elitist and anti properties. Best drama is a creative one hand as a model to implement the principles of aesthetics, art and culture Cultural Revolution period kkophimyeo reference for understanding the aesthetic principles that animated the Chinese Cultural Revolution period of orientation. This paper has San Tu Chu(三突出), Hong Guang Liang(紅光亮), and Gao Da Quan(高大全) at the time of the Cultural Revolution aesthetic principles are reflected in how the concrete work, the Cultural Revolution when the animation is how to accommodate these aesthetic principles and placed emphasis on comparative studies on best pole and correlation of the Cultural Revolution when the Chinese animation to ensure that adaptation in own way. First, after analyzing whether the aesthetic principles of focusing on the similarities of the best pole time of the Cultural Revolution and China, and how to implement animation in the works, these aesthetic principles according to the analysis of positive and negative influence on the creation of Chinese animation It was described as neutral. The detailed analysis and comparative study courses were trying to access in two significant aspects of the characters and scenes directing. In terms of character animation of the Cultural Revolution in China when a young boy or girl, emphasis should emphasize the health tinged with red lips and cheek blush to highlight the desired Gong Nong Bing(工農兵) shape as the main character and smooth texture and sophisticated highlights the glittering feeling to the touch, it was confirmed focused hayeoteum to implement the principle of 'Hong Guang Liang', highlighting the brilliant colors with a clean, bright colors. Highlighting a number of protagoniste compared to the antagonist in the animated scene of the Cultural Revolution a few times in terms of production and, among a number of protagoniste also emphasizes the outstanding hero figure, "yet three outstanding heroes heroic figures also emphasize the leading figures among the the director of the extrusion step-by-step approach "('San Tu Chu')was used. In addition, the hero figure is generally high and low angle by directing a large and perfect aesthetic appearance was to faithfully implement the principle of 'high-charged'('Gao Da Quan').