• Journal of Korean Home Economics Education Association
• /
• v.34 no.3
• /
• pp.67-83
• /
• 2022

This study was designed to develop a sustainable clothing life education program for middle school students and to analyze the effects of the developed program on the "Change-maker" characteristics of adolescents. This study proceeded following the ADDIE teaching design model. The learning activities in the middle school Technology and Home Economics textbooks were analyzed according to the steps of the Change-maker education program. Based on the analyzed results, the sustainable clothing life education program entitled 'Clothes for us, actions for the earth' which includes ten teaching and learning process plans, 17 individual learning activity sheets, and seven group learning activity sheets was developed. The developed program was implemented on 285 first-year students in K middle School in Ulsan. After the class, the level of Change-maker characteristics of the students increased from 3.87(SD=.54) to 4.59(SD=.64). From the interviews of the students, it was also found that the developed program influenced the values and behaviors of the students. Therefore it was confirmed that the Education for Sustainable Development(ESD) program on clothing life in middle school Home Economics developed based on the Change-maker education program stage was effective in cultivating the Change-maker characteristics of adolescents.

• Tribology and Lubricants
• /
• v.22 no.2
• /
• pp.59-65
• /
• 2006

In hard disk drives as the head to disk spacing continues to decrease to facilitate recording densities, slider disk interactions have become much more severe due to direct contact of head and disk surfaces in both start/stop and flying cases. The slider disk interaction in CSS (contact-start-stop) mode is an important source of particle generation and tribocharge build-up. The tribocharge build-up in the slider disk interface can cause ESD (electrostatic discharge) damage. In turn, ESD can cause severe melting damage to MR or GMR heads. The spindle speed of typical hard disk drives has increased in recent years from 5400 rpm to 15000 rpm and even higher speeds are anticipated in the near future. And the increasing disk velocity leads to increasing disk acceleration and this might affect the tribocharging phenomena of the slider/disk interface. We investigated the tribocurrent/voltage build-up generated in HDD, operating at increasing disk accelerations. In addition, we examined the effects with relative humidity conditions and rest time. We found that the tribocurrent/voltage was generated during pico-slider/disk interaction and its level was about $3\sim16pA$ and $0.1\sim0.3V$, respectively. Tribocurrent/voltage build-up was reduced with increasing disk acceleration. Higher humidity conditions $(75\sim80%)$ produced lower levels tribovoltage/current. Therefore, a higher tribocharge is expected at a lower disk acceleration and lower relative humidity condition. Rest time affected the charge build-up at the slider-disk interface. The degree of tribocharge build-up increased with increasing rest time.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.9 no.4
• /
• pp.198-204
• /
• 2009

Inductive peaking using T-coils has been widely used in broadband I/O interfaces. In this paper, we analyze technical effects and limitations of the T-coil, and discuss several methods that can overcome these restrictions and improve the practicality of the T-coil. In particular we also propose and verify a circuit topology which can further extend bandwidth beyond the limit that conventional T-coil can achieve, and transfer 20 Gb/s data without noticeable distortion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.08a
• /
• pp.19-24
• /
• 2002

Static electricity is an everyday phenomenon. There can be few of us who have not experienced a static shock after sliding across a car seat. Other static nuisance effects include the cling of some fabrics to the body, the sticking of a plastic document cover, or the attraction of dust to a TV or computer screen. However, static electricity has been a serious industrial problem. The age of electronics brought with it new problems associated with static electricity and electrostatic discharge. And, as electronic devices became faster and smaller, their sensitivity to ESD increased. In this work, We are study on the control technique of electo-static discharges using semiconductor circuits. Our circuits are prevented well to electrostatic shock or damages from triboelectric charging in cars everyday life.

• Journal of the Society of Naval Architects of Korea
• /
• v.60 no.5
• /
• pp.351-357
• /
• 2023

In this study, we devised methods to enhance the efficiency of rotor sails which have been applied as one of the energy saving devices of ships. The idea of the study originated from the notion that installing protrusions or increasing the surface roughness on the smooth surface of the rotor sail could delay the separation of the incoming wind flow and consequently increase the lift force. Five cylinder models were considered and tested in an open-type wind tunnel at Chungnam National University. A smooth surface cylinder exhibits the highest lift-to-drag ratio at a specific Reynolds number, and as the Reynolds number increases this value decreases sharply. The variation in this typical Magnus force can be significantly improved by altering the surface shape and roughness of the rotor sail. It has been observed that increasing the surface roughness improves the lift characteristics, resulting in increased efficiency. Furthermore, it revealed that the reverse Magnus effect which may occur during actual operation in the low spin ratio region can be significantly enhanced.

• Structural Engineering and Mechanics
• /
• v.61 no.4
• /
• pp.527-538
• /
• 2017

The evaluation of the loss-of-support conditions of frictional beam-to-column connections using simplified numerical models describing the transverse response of a portal-like structure is presented in this paper considering the effects of the seismic-hazard disaggregation. Real earthquake time histories selected from European Strong-motion Database (ESD) are used to show the effects of the seismic-hazard disaggregation on the beam loss-of-support conditions. Seismic events are classified according to different values of magnitudes, epicentral distances and soil conditions (stiff or soft soil) highlighting the importance of considering the characteristics of the seismic input in the assessment of the loss-of-support conditions of frictional beam-to-column connections. A rigid and an elastic model of a frame of a precast industrial building (2-DoF portal-like model) are presented and adopted to find the minimum required friction coefficient to avoid sliding. Then, the mean value of the minimum required friction coefficient with an epicentral distance bin of 10 km is calculated and fitted with a linear function depending on the logarithm of the epicentral distance. A complete parametric analysis varying the horizontal and vertical period of vibration of the structure is performed. Results show that the loss-of-support condition is strongly influenced by magnitude, epicentral distance and soil conditions determining the frequency content of the earthquake time histories and the correlation between the maxima of the horizontal and vertical components. Moreover, as expected, dynamic characteristics of the structure have also a strong influence. Finally, the effect of the column nonlinear behavior (i.e. formation of plastic hinges at the base) is analyzed showing that the connection and the column are a series system where the maximum force is limited by the element having the minimum strength. Two different longitudinal reinforcement ratios are analyzed demonstrating that the column strength variation changes the system response.

• Journal of the Korean Society of Earth Science Education
• /
• v.13 no.3
• /
• pp.253-269
• /
• 2020

The study developed and analyzed programs that incorporate observable worldviews-based science education and education for sustainable development(ESD) in science classes to emphasize integration with the background of the times and achieve effective goals of science education aimed at cultivating scientific literacy. As a result of applying the program to actual high school students, students were able to see the transition to the worldviews of ecology in the process of considering various values and making decisions by identifying their own values. Students' worldviews were found to be at odds during the process of identifying their worldviews and approaching values in various aspects of the class due to the conflicting values of each curriculum and teacher worldviews. In the area of individual values, the worldviews should be applied in science education and understanding of the worldviews of teachers and curriculum contents is also required. Through this study, we hope that access to the area of individual values represented by the worldview in science education will help students change fundamental.