• Proceedings of the KSR Conference
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• 2008.06a
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• pp.481-488
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• 2008

A detail design of overhead catenary system can be divided into a pegging plan and a design of MD(mounting diagram). In the pegging plan, the mast location, staggering and tension length are determined in the longitudinal point of view according to track condition, location of substation and etc. In the MD, a transversal diagram including masts, all of wires, cantilever, foundation and etc. and materials used are shown. This study presents a development of a software to design the MD for a conventional catenary system automatically. In the program, thin walled steel pole, foundation, cantilever, all of wires and etc. are automatically drawn according to the input and catenary conditions. And materials used in the MD and the section can be also managed respectively in the program. This application of the program is developed using C# for input/calculating and using C++(ObjectARX) for drafting the MD, respectively.

• Computational Structural Engineering
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• v.9 no.3
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• pp.199-207
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• 1996

When an initially straight thin cylinder is bent, there is a tendency for the cross section to flatten. This phenomenon was investigated by L.G. Brazier in 1927 and is called "Brazier Effect" or "Brazier Theory". The main characteristic is the reduction of carrying capacity due to the decrease of bending stiffness by shortening of thickness with the increase of external load. And the relationship of curvature-bending moment becomes a soft spring type as shown in Fig.2. In this paper, the Brazier theory on plate type structures is investigated from the following view points : (1) What is the Brazier effect? (2) the reason of the occurrence of the Brazier effect in plate type structures by using beam model and (3) factors which cause the brazier effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.929-934
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• 2009

In this work, the punchless piercing process with application of alternate high pressure has been proposed as a method to obtain pierced holes having nearly vertical wall over thin metal plates. The numerical simulation considering Lemaitre damage model has been accomplished for the proposed method. The simulated results have been compared with those by conventional one-way punch less piercing process. It has been revealed that the fractured section made by pressure alternation method shows nearly steep wall where the deviation angle from the vertical line is as small as $3.6^{\circ}$.

• Korean Journal of Materials Research
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• v.8 no.2
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• pp.131-134
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• 1998

The deposition rate and surface morphology of Al films deposited by MOCVD have been studied on the $SiO_{2}$ and TiN(60nm/Si) substrates. A1 films were deposited with the pyrolysis of dimethylethylamine alane(DMEAA). When A1 was deposited on Ti& substrate without carrier gas, Al deposition rate increased with H\ulcorner pre- treatment. The $H_2$ gas enhances the CVD reaction at the substrate surface. When Al was deposited on $SiO_{2}$ substrate, $H_2$ plasma pretreatment reduced Al incubation time and made a dense Al film compared with Ar plasma pre- treatment or no pretreatment.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.12-21
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• 1990

When a piece of the dorsal skin(cat fish) was observed under a light microscope, melanophores were horizontally expanded and had a few processes filled with melanosomes. They were isolated from one another. Some melanophores looked black, while others were d&k brown. On observation with a transmission electron microscope, the epidermal melanophore of cat fish was highly branched and small segments of processes were found frequendy m the vidnity of the interecellular spaces. The cross section of the processes of melanophore was almost circular, and often invested by a thin layer of epidermal cells. Some processes, however, occurred free m the wide interecellular spaces or at the cytoplasm of the superilcial layers. In the mature melanophore, the cell organelles including melanosomes, mitochondria and free ribosomes were prominent in the perinuclear portions. Many melanosomes were spherical or elipsoidal in shape. Each melanosomes was surrounded by a limiting membrane. The processes of the mature melanophore were well developed, but the processes of the immature melanophores were incompletely developed.

• Journal of the Korea Institute of Building Construction
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• v.6 no.2 s.20
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• pp.111-117
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• 2006

In case of carrying out vortical crossing water distribution system in expressways or general roads construction, VR(Vibrated and Rolled reinforced concrete) pipes are restricted because of their specification of reinforced spun concrete pipe or on-site made pipe. Therefore, in order to apply VR pipes to those constructions, through the structural behavior experiments of the pipes, VR pipes are compared and verified with reinforced spun concrete pipe and the results are obtained as the following. From the experiments and analyses of Pipe Stiffness(PS) of the pipes, cracking loading is approved to satisfy the KS regulations. Through a direct load test, the cracking loading strength and the maximum load test of VR pipe is larger compared with reinforced spun concrete pipe. Particularly, even if side weld is thin, there is no little change in the cracking strength of VR pipe. The results of the direct load test analysis show that the structural behavior of VR pipe is equivalent or higher compared with reinforced spun concrete pipe in performance and VR pipe could be used as the water distribution pipe for roads. In this study, through pipe stiffness, direct load test and load teat on earth, reinforced spun concrete pipe and VR pipe are compared. And as a result, the structural behavior of VR pipe is comprehensively excellent. From the structural behavior tests, VR pipe's section shows more thickness and has uniform characteristics so that VR pipe is considered more favorable than reinforced spun concrete pipe.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.4
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• pp.67-72
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• 1989

Room Temperature Plasma Nitridation of silicon was investigated as a new LOCOS (local oxidation of silicon) process in order to reduce the bird's beak length. In $N_2$ plasma formed by 100kHz, 400W AC power, a thin silicon nitride film (<100${\AA}$) was uniformly grown on a silicon substrate. SEM studies showed that the nitride layer formed by this method can effectively protect the silicon from oxidation and reduce the bird's beak length to $0.2{mu}m$ when 4000${\AA}$ field oxide is grown. This is a considerable improvement comparing with 0.7${mu}m,$ the bird's beak, for the conventional LOCOS process using a thick LPCVD nitride. No appreciable crystalline defect could be found around the bird's beak with SEM cross-section afrer Secco etch. Leakage current tests were carried out on the $N^+/P^-$ well and $P^+/N^-$ well diodes formed by this new LOCOS process. The electrical tests indicate that this new process has electrical properties similar or superior to those of the conventional LOCOS process.

• Korean Journal of Bronchoesophagology
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• v.6 no.1
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• pp.7-15
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• 2000

Background and Objectives:Submucosal spread of hypopharyngeal canceris frequently incriminated for the high incidence of local recurrence after resection. Although mucosal spread is better detected by means of direct visualization, submucosal spread is better evaluated by using cross-sectional imaging rather than endoscopy. This study was designed to evaluate the efficacy of MRI in diagnosing involvement of inferior margin of hypopharyngeal cancer. Materials and Method : Eight patients with hypopharyngeal cancer underwent MRI prior to surgery. And postoperative histopathopogic involvement of tumor was compared with the preoperative MRI axial scan. Results : In preoperative MRI findings, involvement of pyriform sinus apex was 6 cases(definitive 5 cases, probable 1 cases), that of esophageal inlet was 1 case(probable), that of cervical esophagus was 1 case(probable). In postoperative histopathologic findings, the results were same. Conclusion : MRI evaluation for patient with hypopharyngeal cancer ensures accurate staging and provides essential information about the tumor involvement of inferior margin. And there is needed to be thin section thickness in evaluation of inferior margin of hypopharyngeal cancer.

• Journal of the Korean earth science society
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• v.30 no.2
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• pp.176-184
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• 2009

The purpose of this study is to develop and apply the web contents about the optical characteristics of rock forming minerals. The web contents developed in this study are fundamentally made up so as to show clearly the learning objective and the teaching and learning contents, and to review one content easily and search for another content freely. In addition to the web contents, the photos and moving images of the optical characteristics of rock forming minerals cited in the middle and high school textbooks are demonstrated for the students to recognize the mineral characteristics on the screen. The analysis on the quality level and teaming effect of teaching and teaming materials based on the investigation of the MALSAM after the application of the web contents to the class, showed that most students evaluated were effective for understanding the optical characteristics of the rock-forming minerals. About 62% of the students who used the web contents were able to identify the rock-forming minerals on the thin section under the polarizing microscope.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.10
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• pp.537-543
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• 1999

We fabricated a resistive superconducting fault current limiter (SFCL) of a meander type based on a YBCO film with the meander cross section of 5 $\times$ $10^{-6}$$cm^2$, and performed current limitation experiments. The film was coated quench current was 9.6 Apeak at 60 Hz, and the fast quench time was 0.63 msec. The resistance of the limiter continuously increased for three cycles dut to the temperature rise in the gold layer. The temperature of the current limiting element reached the room temperature in 11 msec, $150^{\circ}C$ in 54 msec after quench, and was saturated afterwards. For $45^{\circ}$and $90^{\circ}$faults the fast quench times were 0.56 msec and 0.26 msec, respectively. The quench time is believed to be reduced because the fault occurred when the current was either increasing or at the peak value. This limiter effectively limited the fault current to about 1/5 of the potential current with no SFCL right after the fault and to about 1/8.5 in three cycles. We confirmed that the gold layer effectively carried out the role of heat dissipation as the SFCL was quenched.