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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
Journal Basic Information
Journal DOI :
Korean Society of Precision Engineering
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Volume & Issues
Volume 25, Issue 12 - Dec 2008
Volume 25, Issue 11 - Nov 2008
Volume 25, Issue 10 - Oct 2008
Volume 25, Issue 9 - Sep 2008
Volume 25, Issue 8 - Aug 2008
Volume 25, Issue 7 - Jul 2008
Volume 25, Issue 6 - Jun 2008
Volume 25, Issue 5 - May 2008
Volume 25, Issue 4 - Apr 2008
Volume 25, Issue 3 - Mar 2008
Volume 25, Issue 2 - Feb 2008
Volume 25, Issue 1 - Jan 2008
Selecting the target year
Vibration Control Technologies for Precision Machinery Systems
Choi, Seung-Bok ; Han, Young-Min ; Sung, Kum-Gil ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 7~17
Development of Hybrid Mount Design Against Shock and Vibration
Moon, Seok-Jun ; Chung, Jung-Hoon ; Kwon, Jeong-Il ; Choi, Seong-Bok ; Lee, Hyun-Yup ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 18~25
Input Shaping for Vibration Reduction in Precise Positioning System
Hong, Seong-Wook ; Park, Sang-Won ; Singhose, William E. ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 26~31
Development of Piezoelectric Energy Harvesting Device
Kwak, Moon-K. ; Kim, Ki-Young ; Kang, Ho-Yong ; Kim, Nae-Soo ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 32~38
Multi-sensor Data Fusion Methods Based on the Kalman Filter for Attitude and Vibration Control of the Biped Robot
Song, Min-Geun ; Park, Young-Jin ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 39~46
Filling Imbalance of Elastomer TPVs in Injection Mold with Unary Branch Type Runner System
Han, Dong-Yeop ; Jeong, Yeong-Deug ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 47~52
Recently, the study for filling imbalance in thermoplastic polymer has gradually been increased. However, it is hard to find the researches for filling imbalance of thermoplastic elastomer(TPE). The experiment of filling imbalance was conducted for the three kinds of thermoplastic vulcanizes(TPVs) and PP polymer in the mold with geometrically balanced runner system(Unary Branch Type Runner System). In this experiment, the effects of the melt temperature, injection pressure and injection speed on the filling imbalance were investigated. There was also the imbalance in TPV injection molding process as well as in conventional injection molding with plastics. The tendency of filling imbalance in TPV injection molding specially decreased by taking place the hesitation of TPV melt.
Design and Manufacture of an Electron Detector for Scanning Electron Microscope
Jeon, Jong-Up ; Kim, Ji-Won ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 53~60
Electron detectors used in scanning electron microscope accept electrons emitted from the specimen and convert them to an electrical signal that, after amplification, is used to modulate the gray-level intensities on a cathode ray tube, producing an image of the specimen. Electron detector is one of the key components dominating the performance of scanning electron microscope so that the development of electron detectors having high performance is indispensable to acquire high quality images using scanning electron microscope. In this paper, we designed and manufactured an electron detector and conducted a couple of image capture experiments using it. In particular, scintillator which generates light photons when it is struck by high-energy electrons was manufactured and experimental studies on the optimization of manufacturing condition was carried out. From experiments to evaluate the performance of our detector, it was verified that the performance of our detector is equivalent to or better than that of the conventional one.
An Analysis of the Mechanical Characteristics of the Knife Edges used in the NPL Watt Balance
Choi, In-Mook ; Robinson, Ian ; Woo, Sam-Yong ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 61~68
Of the seven base units of the international system of units, only the kilogram is still defined in terms of a material artifact. One of the experimental approaches opening the way to a new definition of the kilogram is the watt balance To improve the performance of the NPL watt balance, we need to quantify and reduce hysteresis effects in the balance knives. In this paper, we discuss the mechanical characteristics of the knife edges used in the NPL watt balance. The hysteresis mechanism is analyzed using the finite element method. It is found that the cause of hysteresis is not normal stress but shear, and the deformation of the flat, rather than the knife, is an important factor in the hysteresis mechanism. The study presented here, using finite element analysis, suggests that parameters such as material property, tip radius and knife straightness can be more important than others, such as friction coefficient, tip angle, etc.
Global Path Planning of Mobile Robot Using String and Modified SOFM
Cha, Young-Youp ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 69~76
The self-organizing feature map(SOFM) among a number of neural network uses a randomized small valued initial weight vectors, selects the neuron whose weight vector best matches input as the winning neuron, and trains the weight vectors such that neurons within the activity bubble are moved toward the input vector. On the other hand, the modified method in this research uses a predetermined initial weight vectors of the 1-dimensional string, gives the systematic input vector whose position best matches obstacles, and trains the weight vectors such that neurons within the activity bubble are move toward the opposite direction of input vector. According to simulation results one can conclude that the method using string and the modified neural network is useful tool to mobile robot for the global path planning.
Automatic Generation of Interactive 3D PDF Document in a 3D Viewer Environment
Park, Kyeong-Ho ; Choi, Young ; Yang, Sang-Wook ; Song, In-Ho ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 77~85
PDF is widely accepted as a standard document format and now it supports 3D contents as well. Within the engineering application areas, this new 3D feature may be used to support sharing of 3D documents and thus collaboration between engineering departments, suppliers and partners. In this paper, we describe a system that automatically generates formatted engineering documents including 3D data converted from 3D applications such as commercial 3D CAD viewer. The system consists of two major modules. One is U3D conversion module and the other is PDF conversion module. U3D conversion module extracts geometry, view data, assembly and disassembly information from 3D viewer and converts to U3D format, currently in IDTF text file format. PDF conversion module generates a PDF file and inserts U3D data, various annotation information, and scripts for custom generated operations such as assembly and disassembly in the PDF document.
A Study on Prediction of Fatigue Life and Shock Fracture for the Engine Base of Auxiliary Power Unit for Tracked Vehicle
Lee, Sang-Bum ; Chung, Kyung-Taek ; Shin, Jae-Ho ; Jang, Hwan-Young ; Suh, Jeong-Se ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 86~92
This paper is to investigate the behavior of linear static structure stress, the fatigue and experimental shock fracture far engine base in the Auxiliary Power Unit to resolve its restricted electrical power problem. The shock fracture test was experimentally made under MIL standard criteria. The numerical results by finite element method had a good agreement with those from the shock test. The design data of predicting the fracture at the initial crack and the damage behavior of structure with shock and vibration load in the battle field can be obtained from shock test. In the functional shock test, the crack at the side parts of the engine base was found at peak acceleration of 40g.
A Study on the Pressure Pulsation Reduction for a Hydraulic Clutch Operating System
Lee, Choon-Tae ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 93~99
The clutch is a subcomponent of the transmission that is designed to engage and disengage power flow between the engine and the transmission. Recently, the engine power of automobile has been continuously increased because of customer's demand for the bigger one. As the engine power is increased, the vibration transmitted to the hydraulic clutch operating system has been increased. Therefore the demand for the reduction of clutch pedal vibration during the operation of the clutch system has been increased. This paper describes the pressure pulsation reduction characteristics of the damper cylinder which is applied to the hydraulic clutch operating system. And the purpose of this study is to confirm the availability of a simulation model and investigating the test results of hydraulic clutch operating system. The test results are compared with the simulation results. Therefore it may be concluded that the simulation model and test results will be very useful f3r the design of hydraulic clutch damper cylinder.
Deformation Analysis of Self-regulating Bellows in Joule-Thomson Cryocooler
Lee, Sang-Eun ; Lee, Tae-Won ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 100~107
Bellows is an important component in Joule-Thomson cryocooler, which minimize the excessive flow of the cryogenic gas. The bellows is made of Monel 400 and its geometry is an axial symmetric shell. During cool-down process, the pressure and volume within bellows must be satisfied with Benedict-Webb-Rubin state equation. Moreover, Poisson's ratio of Monel 400 is nearly constants, but its Young's modulus varies for a drop in temperature. Under these conditions, bellows contracts in the axial direction like a spring. To evaluate deformation of bellows at cryogenic temperature, the numerical calculation of the volume within bellows and finite element analysis are iteratively used in this research. the numerical results show that deformation of the bellows is approximately linear for change of temperature.
The Transmission Development with P.T.O Axle Design for Work Vehicle Including Multi-faculty
Kwac, Lee-Ku ; Kim, Jae-Yeol ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 108~117
A transmission designed with P.T.O(Power Take-Off) axle for agricultural work vehicles including multi-purpose vehicles has been developed. It is focused on the 4-wheel drive transmission of synchronous contact type for practical use in fruit tree households which is required for a large-sized agricultural vehicle. Concerning to the specification performed, the load capacity is from 500kg to 1,000kg and the safety should be secured for passengers. In addition, the driving condition should also be secured under bad situations of the topographic slope, swampy land and the rest. In order to carry out above tests, a prototype vehicle through strength analysis of transmission design has been manufactured. Consequently, optimal design conditions on the power transmission with multi-purpose vehicle for various jobs are proposed such as an indication of optimal RPM and torque at a certain work situation. The performance test through the prototype of multi-purpose work vehicle is performed and the related data base is achieved. Finally, it is improved on troubles by the analysis of the results of R&D and provided the solutions on problems occurring to mass production in the future.
Vibration Characteristic Study of Bevel Geared System Using Transfer Matrix Method
Lee, Hyoung-Woo ; Bae, Myung-Ho ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 118~126
A new approach to the critical speed calculation of general multi-mesh gear chain system included bevel gear is presented. A transfer matrix mode! based on Hibner's branch method is developed and the natural properties of the branched rotor system are calculated with using the
-matrix formulation. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors, misalignment and the transmitted errors of the gearing are considered, shows that, at the neighborhood of the operating speed, there are the two critical speeds amplifying the first mode and the eighth mode.
A Study of Stress Analysis of Multi-Grain Orthotropic Material by BEM
Kim, Dong-Eun ; Lee, Sang-Hun ; Jeong, Il-Jung ; Lee, Seok-Soon ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 127~133
As the application of the MEMS parts increases, the structural safety of MEMS appears importantly. A lot of MEMS parts are made by a multi-grain silicon wafer, which is an orthotropic material. Moreover directions of the materials on each grain are distributed randomly. The stress analysis for the multi-grain is important factor in order to apply the MEMS parts to industrial applications. The finite element method (FEM) is commonly used by a stress analysis method but the boundary element method (BEM) is known as the result of the BEM is more accurate than that of the FEM since the fundamental solution are used. In this study, we derived the boundary integration equation for the orthotropic material by applying fundamental solutions with complex variables. The multi-region analysis procedure for the BEM and the multi-grain generation procedure by a random process technique are developed in order to apply the analysis of the multi-grain orthotropic material. The discontinuous element is used in order to remove the comer problem in the BEM. The results of the present method are compared with those of the finite element method in order to verify the present procedure.
Fabrication of Master for a Spiral Pattern in the Order of 50nm
Oh, Seung-Hun ; Choi, Doo-Sun ; Je, Tae-Jin ; Jeong, Myung-Yung ; Yoo, Yeong-Eun ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 134~139
A spirally arrayed nano-pattern is designed as a model pattern for the next generation optical storage media. The pattern consists off types of embossed rectangular dot, which are 50nm, 100nm, 150nm and 200nm in length and 50nm in width. The height of the dot is designed to be 50nm. The pitch of the spiral track of the pattern is 100nm. A ER(Electron resist) master for this pattern is fabricated by e-beam lithography process. The ER is first spin-coated to be 50nm thick on a Si wafer and then the model pattern is written on the coated ER layer by e-beam. After developing this pattern written wafer in the solution, a ER pattern master is fabricated. The most conventional e-beam machine can write patterns in orthogonal way, so we made our own pattern generator which can write the pattern in circular or spiral way. This program generates the patterns to be compatible with the e-beam machine from Raith(Raith 150). To fabricate 50nm pattern master precisely, a series of experiments were done including the design compensation for the pattern size, optimization of the dose, acceleration voltage, aperture size and developing. Through these experiments, we conclude that the higher accelerating voltages and smaller aperture size are better for mastering the nano pattern which is in order of 50nm. With the optimized e-beam lithography process, a spiral arrayed 50nm pattern master adopting PMMA resist was fabricated to have dimensional accuracy over 95% compared to the designed. Using this pattern master, a metal pattern stamp will be fabricated by Ni electro plating for injection molding of the patterned plastic substrate.
A Study on Ultra Precision Rotational Device Using Smooth Impact Drive Mechanism
Lee, Sang-Uk ; Jeon, Jong-Up ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 140~147
This paper represents an ultra precision rotational device where the smooth impact drive mechanism (SIDM) is utilized as driving mechanism. Linear motions of piezoelectric elements are converted to the rotational motion of disk by frictional forces generated between the rotational disk and the friction part that is attached to the piezoelectric element. This device was designed to drive the rotational disk using slip-slip motion mechanism instead of stick-slip motion mechanism occurred in conventional impact drive mechanism. Experimental results show that the angular velocity is increased in proportion to the magnitude and frequency of supplied voltage to piezoelectric element and decreased as the preload is increased. In our device, the smooth rotational motion was obtained when the driving frequency has been reached to 500Hz under the driving voltage of 100V.
Relationship between Traction Force and Elongated Displacement Under Graded Manual Traction of Knee Joint
Bae, Tae-Soo ; Heo, Hyun ; Kim, Kyung-Hun ; Ahn, Jae-Yong ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 4, 2008, Pages 148~153
Although manual traction, one of pain therapies, was applied in clinic to relief pain, the study was rare on the manual force and displacement of ligaments at knee joint during manual traction. The aim of this study is to quantify not only manual force at knee joint but also elongated displacement of joint ligament by C-arm scanning and motion analysis. Twenty-one healthy subjects were tested with manual traction from grade I to grade III under neutral position by a physical therapist. We calculated traction force using joint farces of both hands and elongated displacement of joint ligament were measured. The results showed that traction forces by C-arm scanning analysis were averagely 1.67-fold greater than those by motion analysis, but elongated displacements were instead averagely 2.36-fold smaller than motion analysis. Finally, we could estimate relationship between traction force and elongated displacement at knee joint by two methods.