• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.4
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• pp.42-49
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• 2019

This paper presents a method to predict the storage reliability of springs for turbo engine components based on an accelerated degradation test. The reliability assessment procedure for springs is established to proceed with the accelerated degradation test. The spring constant is selected as the performance degradation characteristic, the temperature is determined to be the stress factor that deteriorates the spring constant. The storage tests are performed at three temperature test conditions. The spring constant is measured periodically to check the degradation status of the springs. Failure times of the springs are predicted by using the degradation model. Finally, the storage lifetime of the springs at normal use conditions is predicted using an accelerated model and failure times of all test conditions.

• Resources Recycling
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• v.28 no.3
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• pp.59-67
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• 2019

This study was conducted to fabrication pig iron containing copper and to reduce sulfur content pig iron. Roasting test was conducted for 1 ~ 9 hours at each temperature of $500^{\circ}C$, $700^{\circ}C$, and $900^{\circ}C$. In addition, the effect of oxygen partial pressure with 0.5, 0.8, and 1 atm was carried out for 30 minutes at $900^{\circ}C$. It was found that there is no effect to reduce sulfure in pig iron through roasting and oxygen partial pressures. The addition of CaO with 15 wt.% was found to reduce sulfur content up to 0.001 wt.%. The suitable temperature and reactive time for carbothermic reduction were $1600^{\circ}C$ and 30 minutes which shows the highest recovery rate of iron from the copper slag.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.126-136
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• 2019

The film born by Lumiere brothers in 1895 was not the first. Edison, who invented the Kinetograph four years ago, has already made dozens of films. But it has been relatively undervalued. That's because the platform for projecting a movie was through a single person viewer called Kinetoscope. However, the physical characteristics of the film itself are the same as those of modern films, and have a unique aesthetic distinction compared to other early films. The subject is entertainment-oriented, and the image is characterized by contrast effect. In addition, even before the birth of the film, it shows the important creative elements and genres pursued by fictional films, and has industrial production systems and experts. If Lumiere's film is the beginning of a documentary film that portrays the fact, Edison's film deserves historical value as the beginning of popular film, which is the hallmark of modern cinema.

• Journal of the Korean Wood Science and Technology
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• v.32 no.1
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• pp.52-58
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• 2004

Oak is one of major species in this country as well as pine, but has been less utilized because of its refractory properties. The purpose of this study is to develope an effective method for drying the boards and disks of Quercus variabilis. Among four end-coaters used in this study thick coating with polyvinyl acetate chrolide glue (PVAc) was proved as the most effective. The average air-drying rate of boards was 1.2%MC/day, which did not exceed the safe drying rate recommended by United States Department of Agriculture (USDA). The kiln drying schedule used in this study gave a good result in drying the air-dried boards to 8%MC without any internal checks. An attempt to prevent oak disks from V-cracking during air-drying using special pallet-type stickers was not successful.

• Journal of Korean society of Dental Hygiene
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• v.22 no.5
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• pp.365-374
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• 2022

Objectives: The purpose of this study was to determine the effects of dental hygienists' grit, job satisfaction, and job commitment on dental hygiene job performance and the mediating effects of job satisfaction and job commitment on the relationship between grit. Methods: From May 25 to June 13, 2022, the researcher collected and analyzed data from 213 dental hygienists working at dental hospitals and clinics. For the data analysis, SPSS Statistics 21.0 was applied to conduct a t-test, one-way ANOVA, Pearson's correlation analysis, and hierarchical regression analysis. Results: Grit was in charge of preventive work (scaling) (3.38±0.56, p<0.05), and the lower the stress (3.39±0.57, p<0.05), the higher the grit. Dental hygiene job performance was higher when they worked in Gwangju, Jeolla-do (3.88±0.50, p<0.01), and dental clinics (3.85±0.53, p<0.01). Job satisfaction (3.45±0.49, p<0.05) and job commitment (3.28±0.56, p<0.05) were high, as they had at least a bachelor's degree. Less job stress was associated with higher job satisfaction (3.71±0.42, p<0.001) and job commitment (3.52±0.65, p<0.001). Job satisfaction and commitment had partial mediating effects on the relationship between dental hygienists' grit and job performance. Conclusions: It is necessary to develop a program that helps improve grit in dental hygienists to strengthen their psychological resources, job satisfaction, and job commitment.

• Journal of Korea Entertainment Industry Association
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• v.13 no.8
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• pp.209-221
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• 2019

A found-footage film La France est notre patrie is a documentary, in which archive images are juxtaposed with intertitles, non-diegetic music and foley, by borrowing an audiovisual strategy of silent films. The filmmaker Rithy Panh has excavated the images, which had been taken during the same period as the film history of the end of the 19^th and early 20^th centuries in Southeast Asia and Africa under French colonial rule. This paper examines the filmmaker's methods of historiography when utilizing archive images in order to represent the past by referring to Walter Benjamin's concept of historical montage and dialectical image. As the analysis illustrates the singularity of constructive methods, which include multi-layer viewpoints and montage styles of compilation and collage, it reveals how La France est notre patrie elicits the essay film modes through its self-reflexivity, leads audience to the threshold of critical thinking about time and history and creates a discourse of counter-memory.

• Journal of the Korean Geotechnical Society
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• v.26 no.9
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• pp.59-69
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• 2010

This study is experimentally investigated for characteristics of lightweight air-trapped soils with uniform quality. Previously, EPS (Expanded PolyStyrene) blocks are often used as lightweight embankment, but many problems such as the level difference and cracks were caused by plastic (creep) deformation. So, a new material development is urgent. By means of alternatives, lightweight air-mixed soil using in-situ soils has been developed and applied to fields. In comparison with EPS block, lightweight air-mixed soil has less plastic (creep) deformation in long period, but the strength characteristics are different according to the soils where they are obtained. Therefore, the quality management of lightweight air-mixed soil is very difficult. Therefore in this study, characteristics of lightweight air-trapped soil using a manufactured sand with uniform quality are investigated. To found out the compression and tensile characteristics of lightweight air-tapped soils, unconfined compression test and splitting tensile test are conducted on the specimens prepared with different unit weight, cement-sand ratio and air-pore.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.4
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• pp.17-31
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• 2023

Amidst escalating global warming fueled by indiscriminate fossil fuel consumption, concerted efforts are underway worldwide to mitigate atmospheric carbon dioxide (CO₂) levels. Electrochemical CO₂ reduction technology is recognized as a promising and environmentally friendly approach to convert CO₂ into valuable hydrocarbon compounds, deemed essential for achieving carbon neutrality. Copper, among the various materials used as CO₂ reduction electrodes, is known as the sole metal capable of generating C₂₊ compounds. However, low conversion efficiency and selectivity have hindered its widespread commercialization. This review highlights diverse research endeavors to address these challenges. It explores various studies focused on utilizing copper-based electrodes for CO₂ reduction, offering insights into potential solutions for advancing this crucial technology.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.3
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• pp.153-159
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• 2023

As research results showed that ozonated olive oil has excellent therapeutic effects on skin diseases, attempts were made to develop cosmetics manufacturing technology using ozone. Ozone is harmful to the human body, so a separate facility must be prepared to manufacture ozonated olive oil as a cosmetic raw material. The manufacturing device developed in this study was designed as an optimized process for manufacturing cosmetics while ensuring the safety of workers involved in production. To verify the ozonated olive oil produced from the implemented device, a toxicity test was conducted on animals. After applying ozonated oil (high concentration) to the rabbit's back for 24 hours, mortality, general symptoms and symptoms were measured. A skin irritation evaluation was performed. As a result of the experiment, as a result of evaluating the test substance treatment area after a certain period of time, it was confirmed that no skin irritation was observed in all animals, confirming the safety of the ozonated oil production process and the safety of the product.

• The Journal of the Acoustical Society of Korea
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• v.25 no.6
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• pp.282-290
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• 2006

This paper proposes a new Digital Reverberator that models Analog Helical Coil Spring Reverberator for guitar amplifiers. While the conventional digital reverberators are proposed to provide better sound field mainly based on room acoustics, no algorithm or analysis of digital reverberators those model Helical Coil Spring Reverberator was proposed. Considering the fact that approximately $70{\sim}80$ percent of guitar amplifiers are still with Helical Coil Spring Reverberator, research was performed based not on Room Acoustics but on Helical Coil Spring Reverberator itself as an effector. After performing simulations with proposed algorithm, it was confirmed that the Digital Reverberator by proposed algorithm provides perceptually equivalent response to the conventional Analog Helical Coil Spring Reverberators.