• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04a
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• pp.155-158
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• 2000

Influence of sustain pulse-width on electro-luminous efficiency is experimentally investigated for surface discharge of AC-PDP. A square pulse with variable duty ratio and rising time of 300 ns has been used in the experiment. It is found that the firing voltage is decreased as the pulse-width is increased from 2 ${\mu}s$ to 8 ${\mu}s$ with sweeping frequency range of 10 kHz to 50 kHz. It has been found that the optimal sustain pulse-width is in the range of $3{\sim}4{\mu}s$ under driving frequency range of 30 kHz and 50 kHz, based on observation of memory coefficient, wall charge, and wall voltage as well as luminous efficiency.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.929-931
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• 2006

In this experiment, we have investigated that the transported space charge between sub-pixels in AC-plasma cell discharge. The test pulse 30 V, $5{\mu}s$ was applied to the address electrodes of neighbor cells of discharge occurred cells. And we have measured the transported space charge between sub-pixels in accordance with the various last sustain pulse widths t(time gap between the rising edges of sustain and test pulses) of 0.2 to $3{\mu}s$. It was observed that the peak value of transported space charge has been shown to be 21.5pC at $1.0{\mu}s$. And the IR peak value have been occured after $0.51{\mu}s$ with respect to sustain voltage.

• Composites Research
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• v.23 no.2
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• pp.10-16
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• 2010

$Al_2O_3$ fiber and SiC particle hybrid metal matrix composites (MMCs) were manufactured by squeeze casting method investigated for their tribological properties. The pin specimens had different ratios of fiber to particle content but their total weight fraction was constant at 20 wt. %. Tribological tests were performed with a pin-on-disk friction and wear tester. The investigation of the dry tribological characteristics of hybrid MMCs were carried out at room temperature and elevated temperature of$100^{\circ}C$ and$150^{\circ}C$. The morphologies of worn surfaces were examined by scanning electron microscope (SEM) to observe tribological characteristics and investigate wear behavior. The results revealed that the wear resistance improved with the content of SiCp increased of the planar random (PR) MMCs at room temperature. At the elevated temperature, it revealed that the wear resistance of normal (N) MMCs was superior to that of the PR-MMCs due to PR-fibers were easily pulled out holistically from the worn surface. Meanwhile, the coefficient of friction decreased with the temperature increasing.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.1
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• pp.1-6
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• 2012

This study is damage evaluation for CNG fuel tank during the burst test through the analysis of acoustic emission signals. Kaiser effect until the pressure 420 bar appears, but More than 420 bar by the creep effect appears significantly damaged vessels, and 480 bar pressure, the Kaiser effect of the rising phase was missing. Resonant transducer at 540 bar than 480 bar decreased activity such as energy and count Continually, but increased wideband transducer. In addition, through the rise time or frequency analysis of composite pressure vessels in order to observe the damage mechanisms wideband transducer is more effective than resonant transducer.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.12
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• pp.5937-5946
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• 2012

The term endocrine disruptors is used to describe a variety of natural and manmade substances that have the capacity to potentially interfere with and modify the normal physiology of endocrine system either by mimicking, blocking or modulating the actions of natural endogenous hormones. The rising incidence of breast cancer over the last 50 years and the documented higher incidence in urban as compared to rural areas suggest a relationship to the introduction and increased use of xenoestrogens in our environment. The literature has developed over the last decades where initial experiments on endocrine disruptors did not support an involvement in breast cancer, and then evidence mounted implicating various environmental factors including hormones, endocrine disrupting chemicals and non-endocrine disrupting environmental carcinogens in the pathogenesis of breast cancer. Available data support the hypothesis that exposure to endocrine disruptors in utero leaves a signature on mammary gland morphogenesis so that the resulting dysgenic gland becomes more predisposed to develop tumors upon exposures to additional insults later on during life. Exceptionally, exposure to phytoestrogens could be beneficial to human health. Most of the available data are from well developed countries while the developing countries are still understudied regarding these issues. Here, we raise a note of caution about potential role of environmental toxins including endocrine disruptors in breast cancer development and call for serious measures to be taken by all involved parties in the developing world.

• Fire Science and Engineering
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• v.25 no.3
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• pp.91-98
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• 2011

This study is about fire resistance performance of wood framed lightweight wall including a middle lintel as a traditional wall form in Korea. The target wall is non-loadbearing system which constructed with $38{\times}89$ mm ($2"{\times}4"$) wood frame and fireproof gypsum board covering, including a middle lintel made of $150{\times}150$ mm section glue-laminated timber. As a test results, all specimens have showed fire resistant performance over 90 minutes and tests were maintained until flame occuring on Specimen-l, 2, 3 at 91 min, 97 min and 98 min respectively. Fire resistance of the heat side gypsum board was 45 minutes and charring rate of middle lintel was equivalant with that of usual timber. The wood stud inside wall system showed relatively quick combution characteristic when exposed to high temperature with no temperature rising delaying time caused by moisture evaporation because of the dehydration preceded during the early period of fire side gypsum board resist to heat.

• Journal of Haehwa Medicine
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• v.15 no.2
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• pp.75-93
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• 2006

Chang San-roe re-explained the contents from the 30th question to the 47th question of "Nan Jing" which refered to the Chang-Pu and physiological theories as follows through the western theory which wss different from the tranditioonal chinese theory 1. "Nan Jing" refered to the circulation and the coming into being of Yeong-Wi. He denied that it was classified Yeong from Wi or Eum from Yang. 2. He denied that Sam-Cho was separated to three parts and the theory of "Sam-Cho is name only, not shape", using western medical theory. 3. He denied the view about "Left side is kidney, right side is Myung-Mun" because it was incorrect that kidney was separated to two parts which were Su and Hwa or Eum and Yang 4. Re-explaining the contents of "Nan Jing"- the portions of heart and lungs, the rising and falling of liver and lungs, the relationships of five viscera and sound color smell taste fluid, the relationships of five viscera and nine hole, the relationships of five viscera and O-Chu, the physiological difference of the old and the young owing to the deflection of Yeong-Wi Chi-Heol- he thought that viewing the human body using theory of Eum and Yang, Five elements(五行) was a far-fetched interpretation, so he denied the tranditional chinese theory which understood human body's organs, physiology, pathology. 5. He explained the contents of "Nan Jing"- the portions of the colon and the small intestines, the funtion of the six bowls, the corespondence of Chang-Pu, physical peculiarity of liver, the anatomical aspects which were the sizes, weights, volumes and shapes of the Chang-Pu and the alimentary canal, Chil-Chung-Mun, Pal-Hoe-Hyeolthrough western anatomy and physiology in detail.

• Korean journal of food and cookery science
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• v.33 no.1
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• pp.54-64
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• 2017

Purpose: Pomegranate has been reported to exhibit medical properties such as antimicrobial, antimutagenic, anticancer, and anti-inflammatory effects. Especially the pomegranate peel as a by-product of the juice industry possesses more polyphenols with an antioxidant effect than the pomegranate flesh does. This study aimed to investigate the effect of the pomegranate peel on the quality characteristics of steamed bread. Methods: Steamed bread containing pomegranate peel was prepared with 0%, 1%, 3%, 5%, and 7% replacements of wheat flour with pomegranate peel powder, respectively. Results: The pH of dough significantly decreased from 5.66 to 4.42 with the amounts of pomegranate peel powder rising. After a 1st fermentation, the pH of all groups decreased. With an increase of the pomegranate peel powder level, the fermentation tension decreased from 42.83 mL to 29.03 mL. In addition, the volume, the specific volume, and moisture decreased as the pomegranate peel powder content level heightened. For color, steamed bread added with 7% pomegranate peel powder displayed low lightness but high redness and yellowness. In texture analysis, hardness and chewiness of the steamed bread rose as the pomegranate peel powder content increased, while the springiness and cohesiveness declined. Both total polyphenol and DPPH radical scavenging activity significantly increased with growing levels of pomegranate peel powder. In a sensory evaluation, the group with 1% pomegranate peel powder added showed the highest sensory preference scores for color, flavor, chewiness, taste, and overall acceptability. Conclusion: The results of this study suggest that steamed bread prepared with the addition of 1% pomegranate peel powder is the most optimal product for appropriate quality characteristics.

• Journal of the Korean Data and Information Science Society
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• v.27 no.1
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• pp.169-178
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• 2016

The purpose of this study is to rigorously review extant research on flipped learning that has been given a rising interests as a measure of securing the quality of higher education apart from the improvement of the curriculum. Colleges and universities are criticized for failing in equipping their customers with critical skills, which triggered them to review both curriculum and teaching learning method. In the middle of the teaching and learning method lies the flipped learning. For its relatively short history of research tackling the issues of flipped learning, now is the best time to review the extant studies on the topic to overview and suggest future directions in the field. With the goal in mind, this study restricted the journal articles reviewed to 20 and presented the results based on a conceptual framework derived from a rigorous literature review. Followings are policy suggestions and conditions for successful implementation of flipped learning.

• Convergence Security Journal
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• v.20 no.4
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• pp.197-208
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• 2020

Based on the network infrastructure advanced in the information knowledge society, the structure of computer net work is operated by establishing the composition of network in various forms that have secured the security. In case of computer network of national/public organizations, it is necessary to establish the technical and managerial securit y environment even considering the characteristics of each organization and connected organizations. For this, the im portance of basic researches for cyber training by analyzing the technical/managerial vulnerability and cyber threats based on the classification and map of cyber threats according to the characteristics of each organization is rising. T hus, this study aims to analyze each type of external/internal cyber threats to computer network of national/public o rganizations established based on the dualistic infrastructure network of internet and national information network, a nd also to present the cyber threat framework for drawing the elements of cyber security training, by drawing and analyzing the actual elements of cyber threats through the case-based scenario.