• Journal of the Korean Society for Railway
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• v.20 no.2
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• pp.234-240
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• 2017

In this study, the influences of rail surface roughness on dynamic wheel-rail forces currently employed in conventional lines were assessed by performing field measurements according to grinding of rail surface roughness. The influence of the grinding effect was evaluated using a previous empirical prediction model for dynamic wheel-rail forces; model includes first-order derivatives of QI (Quality Index) and vehicle velocity. The theoretical dynamic wheel-rail force determined using the previous prediction equation was analyzed using the QI, which decreased due to rail grinding as determined through field measurements. At a constant track support stiffness, an increase in the QI caused an increase in dynamic wheel-rail forces. Further, it can be inferred that the results of dynamic wheel-rail analysis obtained using the measured data, such as the variation of QI due to rail grinding, can be used to predict the peak dynamic forces. Therefore, it is obvious that the optimum amount of rail grinding can be determined by considering the QI, that was regarding an operation characteristics of the target track (vehicle velocity and wheel load).

• The Journal of Society for e-Business Studies
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• v.25 no.4
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• pp.15-32
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• 2020

Increasing uncertainties in the technological innovation environment and increasing technology competition also present new challenges in terms of industrial technology security. Therefore, the purpose of this study was to identify the direction of policy change necessary for the improvement of related policies in the future by examining the importance and implementation of the government's industrial technology security support policies for small and medium-sized enterprises engaged in industrial technology innovation activities. As a result of the analysis, first of all, small and medium-sized enterprises that responded to the government's industrial technology security support policy were perceived to be less performing than the importance of the program. These results can be said to mean that selective budget expansion for related policy programs may be necessary, along with efforts to improve the quality of each program. Second, an analysis of the differences in group recognition between new technology certification firms and industrial technology verification(certification) companies showed that significant differences exist between groups for the program. These results suggest that more effective operation of the relevant policies may require policy enforcement in consideration of the level of security and will of each company in industrial technology, as much as the quantitative characteristics of the entity. This study is meaningful in providing the necessary policy directional basic information for the design and execution of more specific and effective industrial technology security policies by presenting empirical research results that domestic small and medium-sized enterprises are aware of about the government's industrial technology security policies.

• Korean Journal of Optics and Photonics
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• v.17 no.3
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• pp.278-284
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• 2006

We have fabricated and measured electrooptic modulator using coupled stack InAs/InGaAs quantum dots. The height of the quantum dot is 16 nm and quantum dots are stacked including an InGaAs capping layer. The peak wavelength of photoluminescence is 1260 nm at room temperature and 1158 nm at 12 K. The operation characteristics of the quantum dots show high modulation efficiency of electrooptic modulator at 1550 nm compared to that of existing III-V bulk and MQW type semiconductor. The measured switching voltage ($V\pi$) is 540 and 600 mV, for TE mode and TM mode, respectively. From the results, the modulation efficiency can be determined as 333.3 and $300^{\circ}/V{\cdot}mm$ for TE and TM modes. The results reported here may lead to the design and fabrication of a novel electrooptic modulator with low switching voltage and high efficiency.

• Korean Journal of Agricultural Science
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• v.12 no.1
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• pp.108-117
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• 1985

The process of conveying of soil with the open auger to cover the seed completly with less power was reviewed by theoretical analysis. The power efficiency, the reasonable range of RPM of the open auger and the velocity of soil conveying to the direction of the shaft are examined to establish the extent of characteristics of the open auger performance. The results of theoretical analysis and application of similitude are as follows: 1. It is possible to predict the power efficiency by the following equation; ${\eta}_p={\frac{P_n}{P_g}}=({\frac{{\omega}_s}{{\omega}_a}}){\cdot}tan{\gamma}{\frac{mg}{(F_mcos{\alpha}+F_scos{\gamma})}}$ 2. The reasonable range of the revolutions per minute of the open auger was presented as follow to cover completely with less power ; $$\frac{4d(L_a-L_i){\cdot}V_w}{{\pi}(D_o^2-D_s^2){\cdot}r{\cdot}{\frac{{\omega}_s}{{\omega}_a}}{\cdot}tan{\gamma}}{{\leq_-}}{\omega}_a{{\leq_-}}({\frac{{\omega}_a}{{\omega}_s}}){\sqrt{\frac{g}{r}}}$$ 3. The velocity of soil conveying to the direction of the auger shaft may be calculated by the equation; $V_h=({\frac{{\omega}_s}{{\omega}_s}})V_a{\cdot}tan{\gamma}$ 4. The factor of RPM was more important than other factors on the power efficiency.

• Korean Journal of Materials Research
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• v.30 no.8
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• pp.383-392
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• 2020

In this paper, AgCl/Ag₃PO₄/diatomite photocatalyst is successfully synthesized by microemulsion method and anion in situ substitution method. X-ray diffraction (XRD), photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy (UV-Vis) are used to study the structural and physicochemical characteristics of the AgCl/Ag₃PO₄/diatomite composite. Using rhodamine B (RhB) as a simulated pollutant, the photocatalytic activity and stability of the AgCl/Ag₃PO₄/diatomite composite under visible light are evaluated. In the AgCl/Ag₃PO₄/diatomite visible light system, RhB is nearly 100 % degraded within 15 minutes. And, after five cycles of operation, the photocatalytic activity of AgCl/Ag₃PO₄/diatomite remains at 95 % of the original level, much higher than that of pure Ag₃PO₄ (40 %). In addition, the mechanism of enhanced catalytic performance is discussed. The high photocatalytic performance of AgCl/Ag₃PO₄/diatomite composites can be attributed to the synergistic effect of Ag₃PO₄, diatomite and AgCl nanoparticles. Free radical trapping experiments are used to show that holes and oxygen are the main active species. This material can quickly react with dye molecules adsorbed on the surface of diatomite to degrade RhB dye to CO₂ and H₂O. Even more remarkably, AgCl/Ag₃PO₄/diatomite can maintain above 95 % photo-degradation activity after five cycles.

• Nuclear Engineering and Technology
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• v.27 no.3
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• pp.301-316
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• 1995

experimental and computational studies ore carried out to investigate the natural convection of the single phase flow in a tank with a heated horizontal plate facing downward. This is a simplified model for investigations of the influence of a core melt at the bottom of a reactor vessel on the thermal hydraulic behavior in a oater filled cavity surrounding the vessel. In this case the vessel is simulated by a hexahedron insulated box with a heated plate Horizontally mounted at the bottom of the box. The box with the heated plate is installed in a water filled hexahedron tank. Coolers are immersed in the U-type water volume between the box and the tank. Although the multicomponent flows exist more probably below the heated plate in reality, present study concentrates on the single phase flow in a first step prior to investigating the complicated multicomponent thermal hydraulic phenomena. In the present study, in order to get a better understanding for the natural convection characteristics below the heated plate, the velocity and temperature are measured by LDA(Laser Doppler Anemometry) and thermocouples, respectively. And How fields are visualized by taking pictures of the How region with suspended particles. The results show the occurrence of a very effective circulation of the fluid in the whole How area as the heater and coolers are put into operation. In the remote region below the heated plate the new is nearly stagnant, and a remarkable temperature stratification can be observed with very thin thermal boundary. Analytical predictions using the FLUTAN code show a reasonable matching of the measured velocity fields.

• The Journal of Korean Medical History
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• v.15 no.1
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• pp.63-146
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• 2002

Huh-Im(許任, 1570~1647) was an acupuncture doctor of Chosun(朝鮮) era through the late 16th century and early 17th century. Even though he was a person of low birth, he participated in the loyal medication through three loyal generations, Sunjo(宣祖), Kwanghaegun(光海君) and Injo(仁祖). He was recognized of his services and became an official, 'Dangsanggwan'(堂上官) and Kyunggi(京畿) district official several times. In the early Chosun era, acupuncture medicine was focused. During the late 16th century, Imjin(壬辰) war aroused more needs about acupuncture medicine, and acupuncture doctors showed remarkable work. Under these circumstances, Huh-Im(許任)'s fame spread throughout the country. Huh-Im(許任) wrote ChimGuKyungHumBang("鍼灸經驗方") in 1644 based on his lifetime clinical acupuncture & moxibustion experience. It was the first specialized book of acupuncture in Chosun era. This event took place 30 years after DongEuiBoGam - Acupuncture Chapter("東醫寶鑑-鍼灸篇") was published. But it was not influenced much by DongEuiBoGam - Acupuncture Chapter("東醫寶 鑑-鍼灸篇") in the form or contents. ChimGuKyungHumBang("鍼灸經驗方") and Huh-Jun(許浚)'s DongEuiBo- Gam - Acupuncture Chapter("東醫寶鑑-鍼灸篇") were the fruits of the middle Chosun, and they are complementary to each other in theory and practice. The chief distinctions of ChimGuKyungHumBang("鍼灸經驗方") are in it's compact and practical edition and a lot of his clinical acupuncture prescriptions mentioned in the book. Huh-Im(許任) not only accepted the existing books such as NaeKyung("內經"), DongInSuHyulChimGuDoKyung and Shin- Eung Kyung("神應經") with his point of view and clinical experience, but also showed creative operation of studies. Indicating incorrect acupuncture points(訛穴), acupuncture remedy based on the visceral pathogenesis(臟腑病機) and the channel pathogenesis, research on new acupuncture points, sorting out plenty of outer meridian acupuncture points(經外奇穴), creating supplementary and purging acupuncture method(鍼補瀉法) which is a change of hand treatment of KiHyoYangBang("奇效良方"), operating variety of acupuncture and moxibustion treatments, and application of acupuncture treatments on surgery field such as intumescences and emergency cases are the examples. Huh-Im(許任)'s ChimGuKyungHumBang("鍼灸經驗方") influenced on the folk remedy books(民間經驗方書) in the late Chosun era. Compact and practical characteristics of the book let acupuncture treatment be freindly to the people. It can be confirmed in JeungBoSanRimKyungJe-Emergency Chapter("增補山林經濟-救急篇") or the formation of SaAmChimBob(舍巖鍼法). ChimGuKyungHumBang("鍼灸經驗方") was introduced to Japan in 18th century and published twice. ChimGuJibSung("鍼灸集成"), known as an acupuncture medical book of late Qing dynasty(淸末, 1874), is confirmed to be an plagiarization of DongEuiBoGam-Acupuncture Chapter("東醫寶鑑-鍼灸篇") and ChimGuKyungHum- Bang("鍼灸經驗方") of 17th century Chosun. Confusions and errors arouse from mistaken editional trend of ChimGuJIbSung("鍼灸集成") which had not disclosed it's original author and the title of the book must be reformed. In this way, fruits of acupuncture of the middle Chosun era including Huh-Im(許任)'s ChimGuKyungHumBang("鍼灸經驗方") will take a right place in acupuncture medicine history.

• Membrane Journal
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• v.25 no.2
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• pp.132-143
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• 2015

Water is an essential resource for humans, but fresh water becomes scarce due to population growth and contamination of limited resources. Membrane technology has been widely used for water treatment, and forward osmosis is a process which does not need high hydraulic pressure for the operation. However, there are needs for (1) development of novel draw solutes causing low internal concentration polarization and reverse salt flux for high water flux, and (2) development of economic recovery method of the draw solutes in the diluted draw solution. Previous researches on the draw solute include $NaHCO_3$ which can be regenerated by about $60^{\circ}C$ heating, sucrose which can make potable water without additional process, and magnetic nanoparticles which can be regenerated by external magnetic field. Using the principles of forward osmosis process, sea water desalination, wastewater treatment, refinement of proteins, energy generation using pressure retarded osmosis process, preparation of diluted fertilizer, and growing algae for biofuel can be conducted. This paper summarizes characteristics of ideal draw solutes, recovery method of the draw solutes, and various application examples.

• Journal of Korea Technology Innovation Society
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• v.21 no.2
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• pp.875-905
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• 2018

Recently China's science and technology development is accelerating, and some technologies have the world's best technology. With the rapid development of science and technology, China has been deeply aware of the importance of science and technology, and many efforts are being made to legislate security regulations to protect their technologies. Korea and other countries are also interested in research security, and research and development cooperation with China is also on the rise. In this paper, we derived some implications by comparing and analyzing China's science and technology security regulation and Korea's national R&D project management regulations. China is also enacting science and technology security regulations as a subordinate to the laws and regulations of science and technology. However, it should be reflected in future legislation that the difference from Korea is composed of separate independent regulations. In particular, the fact that the science and technology security regulations have been enacted separately may be a hint that can be reflected in the nation's future legislation processes. In this paper, major contents of the science and technology security regulations, points to division of knowledge property into scientific and technological cooperation or security tasks, designation of regulations on the characteristics of research security guidelines, and operation of individual national security agencies In addition, in the event that the contents of the related statutes, confidentiality provisions, and import and import control are recorded in this paper, and the results of the joint R&D project are not utilized, or the technology transfer is not carried out.

• Journal of Korean Society of Forest Science
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• v.104 no.4
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• pp.632-639
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• 2015

Working in the forest would require a wide range of skills and experience for specific tasks which involve with a high level of risks to worker's safety. However, there has been a concern on the current standard wage system for forest workers because it does not effectively reflect the characteristics of typical working conditions in the forest. In addition, the current standard wages for forestry workers was estimated based on the construction industry's wage system. Therefore, the purpose of this study is to assess a current wage system through the mail survey method and to develop a new wage system for forest worker which effectively reflects skill sets and experience required for successful completion of the work in the forest. We mailed the survey questionnaire consisting of 19 questions to 659 forest workers and received 188 responses resulting in a 28.5% response rate. The results showed that the current average optimal wages of forest worker, special worker and feller were 97,680won/day, 127,559won/day and 152,403won/day, respectively though there were variations depending on the regions. In developing the new standard wage system, this study suggest the current work types(worker, special worker and feller) could be divided into 5 work types (forest-environment workers, forest operations in beginner, forest operations in intermediate, forest operations in advanced and forest equipment operator) reflecting specialty of forest operation thereby stabilizing the new wage system for forest workers.