• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.11
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• pp.96-102
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• 2019

Reverse engineering involves duplicating a physical part by measuring and analyzing its physical dimensions, features, and material properties. By combining reverse engineering with three-dimensional (3D) printing, engineers can simply fabricate and evaluate functional prototypes. This design methodology has been attracting increasing interest with the advent of the Fourth Industrial Revolution. In the present study, we apply reverse engineering and 3D printing technologies to evaluate a fabricated automotive inner ring prototype. Through 3D printing, inner rings of various densities were prepared. Their physical dimensions were measured with a 3D scanning system. Of our interest was the effect of inner ring density on the physical dimensions of the fabricated prototype. We compared the design dimensions and physical dimensions of the fabricated prototypes. The results revealed that even the 20% density of inner ring was effective for 3D printing in terms of satisfying the design requirements.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.4
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• pp.89-95
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• 2005

Thrust cut off(TCO) system is installed at the port of a rocket motor case forward dome. The snap ring and the closure are escaped sequentially by pulling out a wedge under internal pressure. The hydraulic structural tests of TCO and numerical simulations were performed, and both results were compared to understand the deformation behavior of TCO. By increasing splines symmetrically, the sealing capacity of TCO can be improved significantly. The escape pressure of TCO increases according to the increase of friction coefficient and there is a critical friction coefficient beyond which the snap ring can not be nearly escaped even after forced escape of wedge. Under low friction coefficient the snap ring is contracted to radial direction and easily escaped. But, under high friction coefficient, the snap ring can not be escaped from the port even after severe plastic deformation.

• Tribology and Lubricants
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• v.23 no.5
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• pp.201-206
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• 2007

The bent-axis type piston pump which is driven by the piston rod works on the way that the piston rod drives the cylinder block, so the taper angle of the piston rod and the swivel angle between the cylinder block and the shaft are very important design factors. If the above factors cannot satisfy the conditions of optimum design, the friction loss between the cylinder bore and the piston increases, and the pump can even fail to work under conditions of severe friction and wear. Since the piston reciprocates in the cylinder bore with high velocity, and at the same time it rotates on its own axis and revolves on the center of the cylinder block, the decrease of the volume efficiency generated on account of the leakage between the cylinder bore and the piston. Therefore, to prevent this case, the piston ring is designed at the end of the piston, and the friction characteristics between the piston ring and the cylinder bore are in need of research due to its great influence on the performance of piston pump. Thus, in this paper, the elastic hydraulic oil's lubrication analyses of the film thickness, the pressure distribution, and the friction force, and so on, have been performed, and the lubrication characteristics between the piston ring and the cylinder bore are explored by the results of the numerical analysis, and it is contributed to realize the higher efficiency and the more advanced performance of the bent-axis type piston pump.

• Tribology and Lubricants
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• v.40 no.2
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• pp.54-60
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• 2024

This study experimentally identifies the effects of end shape, clearance, total damper length, journal eccentricity ratio, oil supply pressure, and oil flow rate on the damping coefficient of a squeeze film damper (SFD) with piston ring seal ends and a central groove. The SFD is composed of a lubricating fluid flowing between the outer race of a rolling element bearing and cartridge, along with an anti-rotation pin to prevent the rotation of the outer race. The device provides additional viscous damping to a rotating system. Additionally, piston ring seals attached at both ends of the damper increase the damping coefficient of the rotating system by reducing oil leakage. Because these different design conditions affect the damping coefficient of an SFD, we perform experiments including different conditions. Tests show that the damping coefficient increases significantly in the SFD with piston ring seal ends compared with the SFD with open ends. The damping coefficient also increases with increasing total damper length and journal eccentricity ratio, and decreases with increasing clearance. Additionally, in contrast to the trend observed for the SFD with open ends, the damping coefficient for the SFD with piston ring seal ends increases with increasing supply pressure and flow rate as the frequency decreases but shows consistent results as the frequency increases.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.3
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• pp.7-12
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• 2002

In the measurement of the RF properties, the LTCC substrate must be considered as a system including various conductor patterning processes. In this paper, the LTCC substrate system is compared with a conventional PCB(Printed Circuit Board) substrate such as FR-4, Duroid and Teflon, etc. The microstrip resonator method is employed for the measurement of the RF properties in the range of DC to 20 GHz. Experimental results show that the ring resonator method is suitable for system loss measurement, and the series gap resonator method for dielectric constant measurement. The process of conductor patterning and its effect on the system loss were also studied.

• Bulletin of the Korean Chemical Society
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• v.27 no.1
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• pp.153-154
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• 2006

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.5
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• pp.81-87
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• 1994

This paper proposes a divider structure that combines a carry-propagation-free division algorithm using RSD number system and a self-timed ring structure. The self-timed ring structure enables the divider to compute at a speed comparable to that of combinational array dividers with less silicon area. By exploiting the carry-propagation-free division algorithm, we can achieve further reduction of silicon area and computation time. The algorithm and structure of the proposed divider have been successfully verified through VHDL modeling and simulation. Preliminary experimental results show the effectiveness of the algorithm and structure.

• East Asian mathematical journal
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• v.28 no.3
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• pp.281-285
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• 2012

In this paper, the concept of *-prime ideals in non-associative near-rings is introduced and then will be studied. For this purpose, first we introduce the notions of *-operation, *-prime ideal and *-system in a near-ring. Next, we will define the *-sequence, *-strongly nilpotent *-prime radical of near-rings, and then obtain some characterizations of *-prime ideal and *-prime radical $r_s$(I) of an ideal I of near-ring N.

• Journal of Navigation and Port Research
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• v.26 no.5
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• pp.529-535
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• 2002

Design and implementation methodologies on the performance evaluation system of Two-Channel Ring-Core Flux-Gate Compass (TCRC FG-Compass) are described, with evaluation procedures and methods based on the polynomial regression models. Performance evaluation system consists of a step motor driving unit, a bearing transmitting unit and evaluation programs derived from polynomial regression formulae. Newly designed performance evaluation system enabled the accuracy of TCRC FG-Compass to be ascertained. It was confirmed that the size of residual deviation of TCRC FG-Compass is $2^{\circ}$, while that of the conventional one is $4^{\circ}$. In addition, the design methodology to the self estimation and correction of residual deviations is also discussed.

• KSCI Review
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• v.14 no.1
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• pp.231-239
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• 2006

Geographic information system (GIS) geography reference it talks the software system which is possible. When like this geographic information system in key feature trying to observe the problem which is an expression of geography information in the center, the research and development with 3 dimension expressions is active from 2 dimension expressions of existing and it is advanced. double meaning geography information which is huge to be quick, the place where it controls efficiently there is a many problem, the ring from the dissertation which it sees and 3 dimensions and efficient scene of the GIS rendering compared to the ring from hazard image base modeling and rendering compared to hazard proposal LDI (Layered Depth Images) it uses GIS rendering compared to the ring to sleep it does. It acquired the terrain data of 3 dimensions from thread side base method. terrain data of 3 dimensions which are acquired like this the place where it has depth information like this depth information in base and the LDI, it did it created. Also it was a traditional modeling method and 3DS-Max it used and it created the LDI. It used LDI information which is acquired like this and the GIS of more efficient 3 dimensions rendering compared to the possibility of ring it was.