• Journal of the Korean Institute of Gas
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• v.9 no.1 s.26
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• pp.21-25
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• 2005

This paper was studied on the corrosion behavior of STS 304 for gas boiler in the condensed water, the electrochemical polarization test of STS 304 for gas boiler in the condensed water was carried out. And the corrosion behavior of STS 304 was considered. The main results are as following: 1) As corrosion environment is acidified from neutrality, the polarization resistance of STS 304 decreases and the corrosion potential is less noble. 2) The corrosion reaction mechanism of STS 304 is cathodic control. 3) As corrosion environment is acidified, the passive potential range of STS 304 decreases. Also, the passive current density of STS 304 increases.

• Physical Therapy Rehabilitation Science
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• v.5 no.2
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• pp.63-69
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• 2016

Objective: To evaluate the effects of sit-to-stand (STS) imagery group training (IGT) on STS movement and balance performance for chronic hemiparetic stroke. Design: Randomized controlled trial. Methods: A total of 30 people with chronic hemiparetic stroke (15 for STS-IGT group and 15 for control) were recruited in this study. The STS-IGT group participated in a videotape-based STS-IGT for 30 minutes a day, five days a week for six weeks, while the control group watched a documentary on television for the same period. The STS-IGT focused on a five-stage protocol. Specifically, external imagery was used during the four phases of the STS movement from the seat of the chair to standing up. All of the participants also participated in a regular rehabilitation program. STS movement and balance performance were assessed using three clinical measures. Results: After training, time to perform the 5-repetition STS test significantly increased in the STS-IGT group (change value, $4.0{\pm}2.0$ sec) compared with the control group (change value, $0.9{\pm}0.7$ sec) (p<0.05). There was a greater improvement in Berg balance scale scores in the STS-IGT group (change value, $0.2{\pm}4.1$ points) compared with the control group (change value, $0.3{\pm}0.9$ points) (p<0.05). There was a greater improvement in Timed Up and Go scores in the STS-IGT group (change value, $2.6{\pm}1.5$ sec) compared with the control group (change value, $0.9{\pm}1.0$ sec) (p<0.05). Conclusions: STS-IGT can be considered as a useful option for restoration of STS movement and balance performance for individuals with chronic hemiparetic stroke who are unable to fully participate in physical activities.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.303-306
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• 2005

Two composites of five plies of STS/Al/Al/Al/STS and STS/Al/STS/Al/STS were produced by roll-cladding at $350^{\circ}C$ from ferritic stainless steel (STS) and aluminum (Al) sheets. In order to analyze the strain states during roll-cladding, the evolution of textures at different through-thickness positions in the roll-clad composites was investigated. Simulations with the finite element method (FEM) disclosed that a strain state which was similar to that of normal rolling with a high friction between roll surface and Al sample led to the formation of texture gradients in the Al sheets in the STS/Al/Al/Al/STS composite. Differences in the material velocity of STS and Al in the rolling direction gave rise to the formation of the shear texture in the Al sheets in the STS/Al/STS/Al/STS composite.

• Journal of the Korean Chemical Society
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• v.46 no.1
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• pp.90-96
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• 2002

The STS contents, emphasized in the 6th curriculum, in the chemistry textbooks(II) were analyzed. The STS contents in textbooks showed average value of 2.7%. The chapter of ‘chemical bond and compound' were included 3.8% of STS contents. And the chapter of ‘atomic structure and periodic table', ‘state of material and solution', ‘science of material', and ‘chemical reaction' contained 3.2%, 2.2%, 1.9%, and 1.9% of STS contents, respectively. When the STS contents were analyzed by STS topics of Piel, the results are as follows; 33.7% on effect of technological developments, 27.5% on environmental quality and utilization of natural source, 19.6% on human engineering, 13.8% on energy, and 5.4% on sociality of science. However, there were no topics on population, space research and national defense. When the STS contents were analyzed by student activities of SATIS, most of the activities were research and case study. There were few field activities of practical investigation, problem solving and decision making, research design and stimulation. There were no activities of role play.

• Journal of the Korean Society of Earth Science Education
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• v.5 no.1
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• pp.42-50
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• 2012

The Purpose of this study was to analyze STS contents in elementary school science textbooks according to 6th, 7th and revision 2007 national curriculum. The contents of STS were analyzed by the STS elements of Yager and the STS topics of Piel's standard. Major findings from the analyses are as follows: (1) The STS contents in the science textbooks of the 6th curriculum took up 13.7% and increased to 18.3% in the 7th and 19.0% in the revision 2007, which showed that the textbooks followed the goal of the national curriculum faithfully. (2) Based on the STS elements by Yager's standard, most of STS content is focused on 'Application of science', 'Social problems and issues' and 'Local and community relevance'. (3) Based on the STS topics by Piel's standard, most of STS contents are focused on 'Effect of technological development' and 'Society of science'. These results indicate that recent STS education trends are reflected on the 6th, 7th and revision 2007 textbooks well. However, it is suggested that some improvement is needed, such as diversification of topic.

• Journal of the Korean earth science society
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• v.26 no.3
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• pp.175-182
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• 2005

The purpose of this study was to investigate the effects of STS (Science, Technology and Society) instruction on 5th graders learning motivation and scientific attitudes, using ARCS (Attention, Relevance, Confidence, Satisfaction) strategies. A total of 53 fifth grade students were sampled from an elementary school, and were assigned to the experimental and the control groups. For four weeks, the experimental group was treated with STS instruction using ARCS strategies while the control group was treated with traditional instruction. The result of this study showed that STS instruction using ARCS strategies was more effective in the development of students' learning motivation and scientific attitudes.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.4
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• pp.453-459
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• 2004

25Cr-20Ni series strainless steels have an excellent high temperature strength high oxidation and high corrosion resistance. However, further improvement can be expected of creep strength by work hardening prior creep. In the present study, the effect of prestraining at room temperature on the creep behavior of a Class M(STS310S) and a Class A(STS310J1TB) alloy containing precipitates have been examined. Prestaining was carried out at room temperature and range of prestrain was 0.5-2.5 % at STS310J1TB and 2.0-7.0% at STS310S. Creep behavior and creep rate of pre-strained specimens were compared with that of virgin specimens. Room temperature prestraining produced the creep life that is longer than that of a virgin specimen both for STS310J1TB and STS310S when creep test was carried out at the temperature lower than recrystallization temperature. The reason for this improvement of creep life was ascribable to the interaction between dislocations and precipitates in addition to the dislocation-dislocation interaction in STS310J1TB and the dislocation-dislocation interaction in STS310S. The beneficial effect of prestraining in STS310J1TB was larger than that of STS310S.

• Journal of Korean Elementary Science Education
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• v.21 no.2
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• pp.289-296
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• 2002

The purpose of this study is to analyze STS contents in the elementary school science textbooks developed under the 7th national curriculum. Major findings from the analyses are as follows: (1) The Percentage of STS contents included is 26% by the number of pages, and 40% by the lesson hour, Higher proportions of the STS contents are found in the domains of ‘energy’ and ‘material’. By grade level, the coverage of 5th grade textbooks is relatively low. (2) Most STS topics are related to science rather than technology or society. (3) In many cases, STS contents are used in the whole processes of a lesson. (4) Most activities are 'group activity' or 'experiment.observation'. There are few activities of 'role playing', 'spot study' or 'interview'. These results indicate that recent STS education trends are reflected on the revised textbooks well. However, it is suggested that some improvement is needed, such as diversification of topic or activity.

• Journal of the Korean Chemical Society
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• v.45 no.5
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• pp.491-499
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• 2001

The purpose of this study was to examine for high school chemistry I textbooks published by the 6th curriculum and some foreign STS programs such as Chemistry in the Community, Science and Technology in Society, Chemistry: The Salter's Approach by analyzing STS contents, students' activity, overall structure of the books and space devoted to STS, and to provide improvement schemes for developing high school chemistry I textbooks to be developed by the 7th curriculum in future. It was found that STS topics in the high school chemistry I textbooks were related only to 'social problems and issues', 'applications of science', 'multiple dimensions of science', and STS contents were presented mostly by narration. Students' activities were limited to discussion and survey, and none of the topics were related to 'career awareness', and 'cooperative work on real problems' in high school chemistry I textbooks. On the contrary, a variety of STS topics and activities such as case study related to local and community, practicing decision-making strategies, role play, practical work career awareness were included in foreign STS programs. Desirable directions for the improvement of STS contents and structure of present high school chemistry I textbooks were proposed in this paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.5
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• pp.626-634
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• 2018

These days, widespread use of sensitive loads and distributed generators makes static transfer switch (STS) an essential component in power circuits to achieve a good power quality for AC Grids. In case of a short-circuit fault, previous STS cannot break the fault current. However, the proposed STS has the capability of breaking it quickly as a circuit breaker. Also if there are power quality problems such as Sag/Swell, the proposed STS can quickly transfers the load to the good quality source. Furthermore it is proved that the transfer time of the proposed STS is within one half of period of 3-phase source frequency regardless of the type of load. It is anticipated that the proposed STS may be utilized to realize many stable and reliable AC grid systems.