• 한국생산제조학회지
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• 제21권5호
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• pp.773-777
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• 2012

Recently UV laser micromachining processes is widely introduced to meet the needs of advanced components of IT, BT and ET industries. Due to the characteristics of non-contact and high-speed laser processing, UV laser micromachining is applied to manufacture very thin substrate such as polymer, metals and composite. These minimum line width obtained by UV laser micromachining is generally determined from laser wavelength, optical lens and its numerical aperture. In this paper we will show the lens effect of water droplet on the surface of workpiece to reduce the line width when UV laser light is irradiated and focused through the water droplet. Because of the refraction effect generated by the semi-spherical or spherical shape of water droplet, we can find smaller line width. And water droplet could not only protect thermal deformation, but also carry away burr around micro dent. Firstly fundamental theory of minimum line width was derived from relationship between the geometry of water droplet and laser light trace, and then experimental and simulation results will be finally compared to verify the effectiveness of water droplet lens effect of UV laser micromachining process.

• 대한치과보철학회지
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• 제20권1호
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• pp.7-17
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• 1982

In order to investigate the internal adaptability and cytotoxicity for porcelain fused to metal Ni-Cr alloy, two commercial alloys (Generic Gold-R alloy, Aalba Dent- Valloy)were employed and compared with new developed beryllium free Ni-Cr alloy (KIST-K alloy). After cementation of each crown to abutment die before and after ceramic bonding respectively, dies were mounted to epoxy resin and the internal space was measured between crown and die of each point on sagittal section. The results were as follows: 1) The results show that the space between the crown and the die was largest at the incisal edge, followed by the shoulder or the bevel and chamfer. The least was to be in the axial surface. 2) There were no significant difference in the adaptability of the compared alloys. 3) On day 2 of the experiment the cell multiplication was slightly inhibited by R and K alloys. However, observations taken at day 4 and 7 showed normal cell multiplication process compared to control group. 4) Alloy V exhibited the most severe cell toxicity among the alloys tested on day 2. By day 4 and 7 it showed a decrease level in toxicity, however it did not exhibit normal cell growth as compared to control group.

• Journal of Mechanical Science and Technology
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• 제17권5호
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• pp.629-636
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• 2003

This paper introduces the developed geometry PIG (Pipeline Inspection Gauge), one of several ILI (In-Line Inspection) tools, which provide a full picture of the pipeline from only single pass, and has compact size of the electronic device with not only low power consumption but also rapid response of sensors such as calipers, IMU and odometer. This tool is equipped with the several sensor systems. Caliper sensors measure the pipeline internal diameter, ovality and dent size and shape with high accuracy. The IMU (Inertial Measurement Unit) measures the precise trajectory of the PIG during its traverse of the pipeline. The IMU also provide three-dimensional coordination in space from measurement of inertial acceleration and angular rate. Three odometers mounted on the PIG body provide the distance moved along the line and instantaneous velocity during the PIG run. The datum measured by the sensor systems are stored in on-board solid state memory and magnetic tape devices. There is an electromagnetic transmitter at the back end of the tool, the transmitter enables the inspection operators to keep tracking the tool while it travels through the pipeline. An experiment was fulfilled in pull-rig facility and was adopted from Incheon LT (LNG Terminal) to Namdong GS (Governor Station) line, 13 km length.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.218-223
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• 2000

The shot peening is largely used for a surface treatment in which small spherical parts called shots are blasted on a surface of a metallic components with velocities up to 100m/s. This treatment leads to an improvement of fatigue behavior due to the developed compressive residual stresses, and so it has gained widespread acceptance in the automobile and aerospace industries. The residual stress profile on surface layer depends on the parameters of shot peening, which are, shot velocity, shot diameter, coverage, impact angle, material properties etc. and the method to confirm this profile is only measurement by X-ray diffractometer. Despite its importance to automobile and aerospace industries, little attention has been devoted to the accurate modelling of the process. In this paper, the simulation technique is applied to predict the magnitude and distribution of the residual stress and plastic deformation caused by shot peening with the help of the finite element analysis.

• Strategy21
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• 통권36호
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• pp.150-179
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• 2015

This thesis analyzes Somali piracy as a non-traditional threat to the Sea Lines of Communication (SLOC) and international countermeasures to the piracy. In an era of globally interdependent economies, the protection of sea lines and freedom of navigation are prerequisites for the development of states. Since the post-Cold War began in the early 1990s, ocean piracy has emerged as a significant threat to international trade. For instance, in the Malacca Strait which carries 30 percent of the world's trade volume, losses from failed shipping, insurance, plus other subsequent damages were enormous. Until the mid-2000s, navies and coast guards from Malaysia, Indonesia, Singapore, together with the International Maritime Organization (IMO), conducted anti-piracy operations in the Strait of Malacca. The combined efforts of these three maritime states, through information sharing and with reinforced assets including warships and patrol aircrafts, have successfully made a dent to lower incidents of piracy. Likewise, the United Nations' authorization of multinational forces to operate in Somali waters has pushed interdiction efforts including patrol and escort flotilla support. This along with self-reinforced security measures has successfully helped lower piracy from 75 incidents in 2012 to 15 in 2013. As illustrated, Somali piracy is a direct security threat to the international community and the SLOC which calls for global peacekeeping as a countermeasure. Reconstructing the economy and society to support public safety and stability should be the priority solution. Emphasis should be placed on restoring public peace and jurisdiction for control of piracy as a primary countermeasure.

• 복식
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• 제32권
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• pp.283-292
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• 1997

The country-of-origin may be used as surro-gate indicator when the consumers do not have confidence on quality evaluation. Since the global sourcing is getting popular in inter-national textile and apparel production the ef-fect of country-of-origin should be examined. The purpose of this study was to determine the effect of country-of-origin on product evaluation and its relation to the consumer characteristics. A questionnaire was distribu-ted to 524 respondents aged 18 through 35. The results indicated that the country-of-ori-gin had significant influence on quality evalu-ation. Furthermore product components such as design price fabric and workmanship were also influenced by the country-of-origin. Price was perceived as more affected variable by country-of-origin than design fabric and work-manship. The interest in country-of-origin was different according to the consumer charac-teristics. Among demographics age and in-come turned out to be significant variables to determine the interest in country-of-origin. Shopping habits of respondents such as pur-chasing price of polo-style knit shirt the place to purchase that shirt the number of shirts they have were significantly different accord-ing to the interest in country=-of-origin. The re-spondent had higher interest in country-of-ori-gin were more fashion-conscious more confi-dent on clothing purchase more brand loyal and more sensitive to price of clothin.

• 한국항공우주학회지
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• 제39권11호
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• pp.1005-1012
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• 2011

본 연구에서는 기하학적 비선형 후좌굴해석 및 전역-국지해석을 통하여 얇은 막재에서 주름이 파괴거동에 미치는 영향을 연구하였다. 해석에서 양단노치 및 일단노치를 가지는 사각형 인장시험 시편형상을 고려하였으며 주름이 발생한 경우와 억제된 경우에 대해 각각 해석을 수행하여 그 결과를 비교하였다. 해석결과의 분석을 통하여 주름의 발달에 따라 J-적분값의 변화에 미치는 영향을 조사하였고, 컷 길이에 따른 영향 및 시편형상의 길이 효과에 대해 체계적으로 연구하였다.

• Archives of Pharmacal Research
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• 제27권5호
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• pp.554-561
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• 2004

Trichostatin A, an antifungal antibiotics, and HC-toxin are potent and specific inhibitors of histone deacetylase activity. Histone deacetylase inhibitors are new class of chemotherapeutic drugs able to induce tumor cell apoptosis and/or cell cycle arrest. In this study, the antiproliferative activities of trichostatin A and HC-toxin were compared between estrogen receptor positive human breast cancer cell MCF-7 and estrogen receptor negative human breast cancer cell MDA-MB-468. Trichostatin A and HC-toxin showed potent antiproliferative activity in both MCF-7 and MDA-MB-468 cells. In MCF-7 cells that contain high level estrogen receptor, trichostatin A and HC-toxin brought about three-times more potent cell growth inhibitory effect than estrogen receptor negative MDA-MB-468 cells. Both trichostatin A and HC-toxin showed cell cycle arrest at G$_2$/M phases of MCF-7 and MDA-MB-468 cells in a dose- and time- depen- dent manner. Trichostatin A and HC-toxin also induced apoptosis from MCF-7 and MDA-MB-468 cells in a dose- and time-dependent manner. Results of this study suggested that antipro-liferative effects of trichostatin A and HC-toxin might be involved in estrogen receptor signaling pathway, but cell cycle arrest and apoptosis of trichostatin A and HC-toxin might not be involved in estrogen receptor system of human breast cancer cells.

• 한국자동차공학회논문집
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• 제12권6호
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• pp.16-22
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• 2004

Dimethyl Ether (DME) has been considered as one of the most attractive alternative fuels for a compression ignition engine. The major advantage of DME-fuelled engine is a great potential for soot-free combustion without sacrificing an inherent high thermal efficiency of diesel engine, despite a necessity for modification of the conventional fuel injection system. An experimental study on DME and conventional diesel sprays was conducted by employing a common-rail type fuel injection system with a 5-holes sac type nozzle, including a constant volume vessel pressurized with nitrogen gas. The injection rates of DME and diesel fuel were recorded with the Bosch type injection rate meter. The injection delay of DME was shorter than that of diesel fuel. The measured injection rates of DME and diesel fuel were correlated with spray penetrations. The prediction method of spray penetration was established using the injection rates, which was verified with the Dent's penetration model and found to agree well for DME case.

• 한국철도학회논문집
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• 제8권1호
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• pp.63-81
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• 2005

In this Paper, Ⅰ illustrate the continuity and severance of Korean railroad. The Korean railroad has been running for 105 years now since it started operation in 1899. Between 1905 and 1945, Japan's imperial government ruled Korea including operations of the railroad. After Korea restored its sovereignty, Korean nationals managed the Korean railroad with our own ability and strategies. At present, we can examine the effect of railroad in perspective of continuity and severance respectively. For one thing, the concept of continuity is described as influence or railroad still remains. For another, the severance shows facts and phenomena that are broken off. I have come up with some facts that are involved with continuity. For example, infrastructure and the formation of cities and land spaces are connected with the sequence. Futhermore, the railroad has made a huge dent in modernization and expedition of movement. In the course of tracing down the facts, I classified the concept of severance : the separation of South and North Korea, drastic changes in transport policy, operations and characteristics. Finally technology has brought about a major breakthrough with the development of Koran high speed rail.