• 해운
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• no.2 s.25
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• pp.22-33
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• 2006

세계해운시장에서 그리스의 역할은 막중하다. 그리스 선주들이 직접 운항하는 선대는 많지 않지만 지배선단은 세계해운시장을 좌우할 정도로 그 규모가 크다. 세계 원유와 정유의 60%가 해상 운송되고 있는데, 그 중 25%가 그리스 유조선에 의해 운송되고 있을 정도이다. 그리스가 세계해운 1위국의 위치를 고수하는 저력은 어디서 나오는지, 그리스 해운산업의 현주소를 알아본다(편집자 주)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.8-15
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• 2019

In this study, we synthesized a calcium sulfonate complex grease and a lithium complex grease to investigate their physical, rheological and tribological properties. The thermal stability of the calcium sulfonate was higher than $300^{\circ}C$ and the lithium complex grease was $245^{\circ}C$ in the dropping point test. In the grease viscosity measurement, the calcium sulfonate complex grease was measured as $7.0Pa{\cdot}s$ and the lithium complex grease was as $4.5Pa{\cdot}s$. Therefore, it was confirmed that the calcium sulfonate complex grease is superior to the lithium complex grease in terms of thermal stability and cohesiveness. In the 4-ball wear test, the calcium sulfonate complex grease was measured to be 0.43 mm and the lithium complex grease to 0.85 mm. In the 4-ball extreme pressure test, calcium sulfonate complex grease was measured as 620 kgf and the lithium complex grease was as 125 kgf. Therefore, it was confirmed that the calcium sulfonate complex grease is superior to the lithium complex grease in abrasion resistance and load-bearing property. It was found that the calcium sulfonate complex grease is more effective than the lithium complex grease in the lubrication at high temperature and high load.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.434-443
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• 2023

We have investigated the performance improvement of grease by synthesizing calcium sulfonate grease as an alternative to lithium grease, which is widely used globally. Since the composition ratio of the grease, when manufactured, is usually 50% base oil and 50% thickener, using grease as a lubricant in a cryogenic environment is not encouraged due to its inferior low-temperature performance. In this study, we have synthesized three types of calcium sulfonate grease with paraffin oil and PAO-based base oil and thickener. Furthermore, lithium grease was synthesized via saponification with PAO-based base oil, lithium hydroxide, 12-hydroxystearic acid, and sebacic acid. We have measured low-temperature characteristics using a rheometer and low-temperature torque meter, and tribology characteristics were obtained using a four-ball lubricant tester and schwingung reibung verschleiß (SRV). As a result, the flow point of the calcium sulfonate grease synthesized with a PAO-based base oil and thickener was found to be -40℃, overcoming the existing calcium sulfonate grease's low-temperature limitation. Moreover, the synthesized calcium sulfonate grease showed low-temperature performance similar to that of lithium grease synthesized with PAO base oil, but superior anti-wear, extreme pressure, coefficient of friction, heat resistance, adhesion, and corrosion resistance. It is thus expected to commercially replace the existing lithium grease.

• Archives of design research
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• v.16 no.4
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• pp.345-354
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• 2003

The Greek theater was the first one which was built artificially and the Roman theater was erected as creative form following the Greek theater The style of these ancient theaters has influenced modern theater. In terms of the purpose and function of the theater, the Greek was derived from religious purpose but the Roman was derived for amusement. We can observe several differences in comparing the Greek with the Roman theater. In the shape of the theater, the Greek theater was dignified and grand and had an open-air structure, but the Roman theater was splendid and ornamental and had a roof over the stage. In the character of the theater, the Greek theater was democratic but the Roman theater was partial. The Greek and Roman theaters have became one source of the modern theater as the Greek and Roman plays have became the source of the modern play, although there are several differences according to the social and dramatic characters.

• Journal for History of Mathematics
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• v.24 no.1
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• pp.45-61
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• 2011

The starting point of education is the ancient Greek philosophy. In this paper, we research the Hellenism culture: two famous poleis such as Sparta and Athens. Moreover, we investigate prominent philosopher Plato and Aristotle. In particular, we notice early childhood and female education through Hellenism culture. Finally, we study culture, politics and educations of the ancient Roman in order to compare those of our society.

• Journal for History of Mathematics
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• v.4 no.1
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• pp.25-34
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• 1987

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.634-643
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• 2020

In this study, the rheological and tribological properties of urea grease were studied according to the type and amount of polytetrafluoroethylene (PTFE) powders added to the urea grease, which is the most widely used among solid lubricants, to develop an optimal lubrication system. Urea grease was synthesized using 4,4'-methylenebis(phenyl isocyanate)(MDI), oleylamine, and cyclohexylamine, and PTFE powders prepared by dispersion or suspension polymerization process were then added. The basic rheological and tribological properties of the prepared greases were compared. The worked penetration numbers of urea grease decreased with increasing amount of PTFE powders, but both PTFE powders caused no significant changes in heat resistance and copper corrosion resistance. The shear viscosity increased with increasing PTFE powder content, and the dispersion-type PTFE powder was more effective in increasing the viscosity. In the value of the loss coefficient = 1, the shear stress was higher for the grease containing PTFE powders than the non-PTFE added grease, and the dispersion-type PTFE-added grease showed higher viscosity than the suspension-type PTFE-added grease. Finally, urea grease was found to have a low-performance improvement in terms of wear reduction effects by adding PTFE powders, but the load-bearing performance was up to 2.5 times higher for the dispersion-type PTFE and five times higher for the suspension-type PTFE.

• Journal of Korean Philosophical Society
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• v.126
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• pp.345-376
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• 2013

Der vorliegende Beitrag zielt darauf ab, Nietzsches Einstellung zum Christentum zu $er{\ddot{o}}rtern$. Nietzsche gilt als einer der eindeutigsten Kritiker des Christentums in der $abendl{\ddot{a}}ndischen$ Geistesgeschichte. $F{\ddot{u}}r$ Nietzsche ist das Christentum nicht nur eine Religion, sondern auch eine Wertvorstellung, an der sich die $europ{\ddot{a}}ische$ Kultur orientiert hat. Nietzsche setzt sich die $vollst{\ddot{a}}ndig$ ${\ddot{U}}berwindung$ des Christentums zum Ziel, weil es der entscheidende Grund des Untergangs der $europ{\ddot{a}}ische$ Kultur ist. Ist Nietzsche Antichrist? Die Antwort auf die Frage ist sehr umstritten, denn Nietzsches Einstellung zum Christentum ist ambivalent. Freilich fokussiert Nietzsche seine Kritik nicht auf den Religionsstifter selbst, sondern auf den Apostel Paulus. In den verschiedenen Phasen seines Werkes erscheint Jesus in unterschiedlicher Weise. Er lehnt die Person Jesus nicht $grunds{\ddot{a}}tzlich$ ab, negiert aber den 'Typus' Jesus, z. B. als 'Idiot' und 'decadent'. Paulus ist der entscheidende Antipode $f{\ddot{u}}r$ Nietzsche. Der Apostel Paulus ist der wahre $Begr{\ddot{u}}nder$ des Christentums und der Sklavenmoral der Christen. Der vorliegende Aufsatz gibt Antworten auf die Fragen: Erstens, was das Christentum $f{\ddot{u}}r$ Nietzsche ist. Zweitens, wie Karl Jaspers Nietzsches $Verh{\ddot{a}}ltnis$ zu Jesus und Paulus besonders in Nietzsche und das Christentum beurteilt. Drittens, welches Problem die Interpretation von Jaspers besonders in Bezug auf seinen Begriff des 'Umgreifenden' hat.

• Journal for History of Mathematics
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• v.20 no.2
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• pp.47-58
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• 2007

In this paper, we shall try to give a comparative study of mathematics developments in ancient Greece and ancient Oriental mathematics. We have found that the Oriental Mathematics. is quantitative, computational and algorithmetic, but the ancient Greece is axiomatic and deductive mathematics in character. The two region mathematics should be unified to give impetus to further development of mathematics in future times.

• Electric Engineers Magazine
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• v.236 no.4
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• pp.25-32
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• 2002

기원전 600년경 그리스 사람들은 장식품으로 사용하던 호박을 헝겁으로 문지르면 먼지나 실오라기 따위를 끌어당긴다는 것을 알고 있는데 이것이 인간이 최초로 발견한 전기현상이다. 전기를 영어로 일렉트리시티라고 하는데 이것은 그리스어의 엘렉트론에서 유래한 말로 본래는 호박을 의미하고 있다.