• Tribology and Lubricants
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• 제36권1호
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• pp.27-33
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• 2020

Self-equalizing tilting pad thrust bearings are usually employed in turbomachines to achieve high stability and reliability. A tilting pad bearing can incorporate self-equalizing links to handle the misalignment between the bearing and the thrust collar. In this popular design method, the pads sit on the upper-level plates and the lower-level plates stay on the retainer base. With misalignment, the pads that are heavily loaded are pushed down. Consequently, the link pushes up the pads on the opposite side, keeping the bearing surface parallel to the thrust collar surface. The self-equalizing link is used to handle the misalignment from the thermal and mechanical effects. In this study, the experimental investigation deals with the performance of self-equalizing tilting pad thrust bearings. The test rig for evaluating the performance of bearing is developed which can control the misalignment angle. Simultaneous measurements are taken for the force acting on each pad. Pad metal temperature and oil film thickness are functions of the shaft speed, bearing load, misalignment angle, and design of leveling plates. The effect of misalignment on bearing performance is discussed. The results demonstrate that the load on each pad depends on the test conditions(especially misalignment angle), and the load influences the performance of bearings.

• 한국광학회지
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• 제11권4호
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• pp.279-288
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• 2000

다양한 종류의 펄스형 Nd:YAG 레이저 공진기를 구성하여 출력경의 각도변화에 따른 레이저 출력에너지의 변화를 최대 출력에너지가 반으로 줄어드는 점의 각도변위인 반치폭 (FWHM)을 측정하여 비교하였다. 출력경의 기울어짐에 대하여 높은 반치폭을 갖고 반사경의 각도변화에 대해서도 덜 민감하게 반응하는 안정적인 펄스형 고체 레이저의 새로운 공지기를 구성하였다. ABCD 광선 전파 행렬식을 이용하여 이러한 공지기의 전파행렬식이 단위행렬이 됨을 해석함으로서 높은 정렬 안정성을 가지고 있음을 증명하였다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.239-242
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• 2005

This paper introduced an approach of improvement of performance of Electric device for EMU type Train like as TTX. The electric equipments are characterized by insulation, Noise, cooling system etc. and Their weight arc decided by these factors. There are two kinds of power source in EMU train. First, DC voltage source, 1500 volt, 750 volt is used for subway system. Second, AC power source 25000 volt is applied to high speed train and existing main lines. Composite material has the protection of inrush current and high frequency noise. We can use this material to minimize weight of train. Additionally we can get energy saving when operator service TTX.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.272-274
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• 2004

Test evaluation field of railroad system that safety and reliability are important is to verify basic performances of unit products and system that were producted according to the specifications. Also, it is important works that verify finally in respect to commercialize verifying reliability and safety. As one part of system technology, this field is to construct database based on know-how of accumulated technology till now than high technical idea and, is to construct test evaluation system of railroad system that can utilize the constructed database. According to the necessity, our researchers investigated good measuring system of foreign country and performed research on performance test and evaluation technology of high-speed tilting vehicle that suits to domestic state.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
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• pp.297-300
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• 2009

Recently, TTX(Tilting Train eXpress), EMU (Electric Multiple Unit) has operated test. Presently, electric problems(harmonic, voltage variation etc) of TTX are studying briskly. Henceforth, electrical harmonic study of TTX will operate on the rail actually is needed. In this paper, we detected electrical harmonic of operating TTX. In addition to we analyzed and estimated electrical harmonic regarding TTX's coasting, acceleration and braking state.

• 한국생산제조학회지
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• 제21권1호
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• pp.156-160
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• 2012

Recently WCDMA signal transmission technology by large output microwave antenna have showed reduction of human resources and operating expense. But the existing antenna brackets cost is very expensive also its structure and functions are complicated. Unit brackets, suspending some sensors, subjected to acceleration loads, often fail due to self-vibration. To prevent such failures, it is necessary to understand the fatigue failure mode and to evaluate the fatigue life using tests or analysis techniques. The objective of this study is to develop the component test specifications, which are applicable to predict fatigue life at initial product design step, for unit brackets using vibration fatigue technique. So its application is limited to installation and management. In this project, we studied about more convenient bracket for microwave antennas through improvement on the existing antenna bracket's shortcoming and could develop an improved universal antenna bracket system for simple installation and application.

• 한국기계가공학회지
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• 제6권3호
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• pp.85-91
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• 2007

This study was carried out to minimize the lifting force of a two hinge type stand mechanism. This unit is designed for the display devices in order to enhance the ergonomics for effective height adjustment and maintenance at any preferred position. The unit will be very useful for the mechanism fabricated with a coil spring and disc springs as a torque generator. The maximum and the minimum torque value should be calculated initially for the smooth lift. And the reasonable torque distribution is necessary to prevent any auto lift and auto dropping at any position because the torque generated by coil spring is more sensitive than disc spring in tilting the position. Therefore, the analysis of the coil spring is requisite to issue the specific torque value depending on the distorted angle with securing reliability of a long time storage condition. After the theoretical torque value was calculated, the evaluation was carried out by making a proto-type sample, then distorted angle was updated by experiment. The result of this study can readily be applied to various units for the optimization of the smooth lift.

• 한국세라믹학회지
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• 제36권7호
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• pp.762-766
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• 1999

The crystal structure of A2+(Mg1/3Nb2/3)O3,(A2+=Sr2+ and Ca2+)ceramics was studied usig X-ray diffraction (XRD) and high resolution transmission electrion microscopy(HRTEM). Ba(Mg1/3Nb2/3)O3 (SMN) has the 1:2 ordered monoclinic structure which has the anti-phase tilt of octahedra. The type of tilting in SMN was considered to be a$^{\circ}$a$^{\circ}$c- or a­a­c$^{\circ}$ Ca(Mg1/3Nb2/3)O3 (CMN) also has the 1:2 ordered monoclinic structure which was distorted by the anti-phase tilt or in-phsae tilt of octahedra. A unit cell containing both the in-phase tilt axis and anti-phase tilt axis was not observed in the CMN. Therefore CMN has the mixed phase consisting of the 1:2 ordered monoclinic phase with anti-phase tilt of octahedra and the one with in -phase tilt of ocatahedra,. The anti-parallel shift of cation was also observed in the CMN.

• 한국해양공학회지
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• 제8권1호
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• pp.50-61
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• 1994

A 300 meter class ROV(CROV300) is composed of three parts : a surface unit, a tether cable and an underwater vehicle. The vehicle controller is based on two processors : an Intel 8097-16-bit one chip micro-processor and a Texas Instruments TMS320E25 digital signal processor. In this paper, the surface controller, the vehicle controller and peripheral devices interfaced with the processors are described. These controllers transmit/receive measured status data and control commands through RS422 serial communication. Depth, heading, trimming, camera tilting, and leakage signals are acquired through the embedded AD converters of the 8097. On the other hand, altitude of ROV and lbstacle avoidance signals are processed by the DSP processor and periodically fetched by the 8097. The processor is interfaced with a 4-channel 12-bit D/A converter to generate control signals for DC motors an dseveral transistors to handle the relays for on/off switching of external devices.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.3027-3031
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• 2011

In this study, By the time that TTX technology is adopted as railway rolling stock, we analyzed quantitatively energy saving by reducing the power consumption with the reduction of the operation time through the speed improvement and suggested the necessity to introduce TTX technology in the domestic rail vehicles. The effect of energy saving by comparing and analyzing the power consumption during the operation by TTX Hanvit 200 and 8200 electric locomotives to pull trains on the same line was suggested and the efficiency of the main devices(i.e C/I) of Hanvit 200 was compared and analyzed by measuring the power consumption by a single unit. For improving KORAIL management environment, reducing energy usage is an urgent challenge, its measures for solving them are constantly considered in many areas. In addition, at the time of improving the conventional track to speed up and changing the signals, Tilting technology will be contributed to the management environment by enlarging the passengers' demand through the reduction of the operation time and saving energy using the existing infrastructure.