• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.579-584
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• 2008

A nano-imprinting stage has been widely used in various fields of nanotechnology. In this study, an analysis method of a nano-imprinting stage machine using FEM and flexible multi-body vibration has been presented. The simulation using CAE for the imprinting machine is to analyze vibration characteristics of 3-axis nano-imprinting stage and 4-axis nano-imprinting stage. Structural components such as the upper plate have been modeled with finite elements to analyze flexibility effects during the precision stage motion. In this paper flexible multi-body dynamic simulation is executed to support robust design of the precision stage mechanism.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.890-893
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• 2004

The ultra precision machining in industrial field are increased day by day. The diamond turning has been used generally, but now is faced with limitation of use, because of higher requirement of production field. The electron beam lithography is alternative in machining area as semiconductor production. For EB lithography, 5 axis vacuum stage is required to duplicate small and large patterns on wafer. The stage is composed of 2 rotational axis and 3 translational axis with 5 DC servo motors. The positioning repeatability and resolution of Z axis feed unit are 3.21$\mu$m and 0.5 $\mu$m/step enough to apply to lithography.

• 한국공작기계학회논문집
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• 제16권5호
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• pp.211-217
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• 2007

A nano-imprinting stage has been widely used in various fields of nanotechnology. In this study, an analysis method of a nano-imprinting stage machine using FEM and flexible multi-body kinematics and dynamics has been presented. We have developed a virtual imprinting machine to evaluate the prototype design in the early design stage. The simulation using CAE for the imprinting machine is not only to analyze static and dynamic characteristics of the machine but also to determine design parameters of the components for the imprinting machine, such as dimensions and specifications of actuators and sensors. Structural components as the upper plate, the rotator, the shaft and the translator have been modeled with finite elements to analyze flexibility effects during the precision stage motion. In this paper flexible multi-body dynamic simulation is executed to support robust design of the precision stage mechanism. In addition, we made the 4-axis stage model to compare the dynamic behavior with that of 3-axis stage model.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1207-1210
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• 2003

This paper deals with experiments for dynamic characteristics and performance evaluation of the 3-axis fine positioning stage developed in [1]. The features of the developed fine positioning stage are the long stroke due to the magnetically preloaded PZT actuators, the minimum motion crosstalk due to the use of a ball contact mechanism and the compact design. The dynamic characteristics of the actuator and the stage are tested with the preload changed in order to validate the actuator and the stage design. Performance evaluation is also made for the PZT actuators as well as the stage positioning accuracy. Experimental results show that the developed stage is accurate enough to be used for nanometer positioning.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.844-849
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• 2008

A nano-imprinting stage has been widely used in various fields of nano-technology. In this study, A 4-axis nano-imprinting stage is modeled with using the 3D-CAD Tool. Structural components such as an upper-plate, bearings and cross-roller-guides are modeled with finite elements to analyze flexibility effect during the precision stage motion. In addition, Dynamic analysis is executed to reproduce actual motion of 4-axis nano imprinting stage.

• 한국정밀공학회지
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• 제23권9호
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• pp.179-189
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• 2006

Recently the electrostatic 2-axis MEMS stages have been fabricated f3r the purpose of an application to PSD (Probe-based Storage Device). However, all of the components (platform, comb electrodes, springs, anchors, etc.) in those stages are placed in-plane so that they have low areal efficiencies such as a few percentage, which is undesirable as data storage devices. In this paper, we present a novel structure of an electrostatic 2-axis MEMS stage that is characterized by having a large areal efficiency of about 25%. For obtaining large area efficiency, the actuator part consisting of mainly comb electrodes and springs is placed right below the platform. The structure and operational principle of the MEMS stage are described, followed by a design and analysis, the fabrication and measurement results. Experimental results show that the driving ranges of the fabricated stage along the x and y axis were 27$\mu$m, 38$\mu$m at the supplied voltages of 65V, 70V, respectively and the natural frequencies along x and y axis were 180Hz, 310Hz, respectively. The total size of the stage is about 5.9$\times$6.8mm$^2$ and the platform size is about 2.7$\times$3.6mm$^2$.

• 한국잠사곤충학회지
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• 제16권2호
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• pp.119-125
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• 1974

정상잠이 3령의 성식기에 이르렀을때(춘잠기 소잠후약 9일 20시간 경과한 무렵) 불면잠으로 인정되는 것과 같은 잠박에서 정상잠을 재료로 하여 이를 고정하였고 또한 4령의 성식기에 1~2령기의 발육정도 밖에 되지 않은 왜소잠을 수집하여 고정하고 이와 동시에 이때의 정상잠도 고정하였다. 불면잠과 정상잠을 형태학적으로 비교하고 그 조직검사에서 얻은 조사내용을 요약하여 보면 다음과 같다. 1. 정상잠이 3령의 성식기에 이르렀음에도 불면잠으로 인정되는 누에는 마치 소잠후 2일이 경과한 정도의 누에의 크기에 불과하였으며 4령의 성식기에 관찰한 불면잠도 이와 대동소리라하였다. 2. 태피선은 타원형의 편평한 낭상체로서 그 크기는 흉부에 위치하는 것이 작고 복부의 것이 일반적으로 큰 경향을 나타냈다. 3. 흉부에 있는 태피선은 흉지의 기부에 있는 것이 배맥관을 끼고 있는 태피선보다 큰것으로 종내에는 보고되었지만 본실험결과에 었어서는 일정한 경향이 없었다. 4. 정상잠이 3령의 성식기에 이르렀을 때의 태피선의 크기는 전흉에 있는 것이 최소로서 151.3$\mu$(major axis)~94.5$\mu$(minor axis)였고 최대로서는 복부제7절의 것이 568.6$\mu$~495.$\mu$였으며 이때에 불면잠으로 인정되는 것은 최소로서 전흉에 있는 태피선이 57.5~51.3$\mu$이였으며 최대로서는 복부제5절의 것이 91.5~75.5$\mu$으였다(표 1. 참조) 5. 정상잠이 4령의 성식기에 이르렀을 때 정상잠과 왜소잠의 태피선의 크기를 비교해 본 바에 의하면 정상잠에 있어서는 전흉의 것이 최소로서 252.2~131.6$\mu$이였고 복부제7절의 것이 최대로서 691.5~493.4$\mu$이였으며 왜소잠에 있어서는 후흉의 것이 최소로서 71.4~61.5$\mu$이였고 복부제8절의 것이 최대로서 94.6~71.5$\mu$이였다(표 2. 참조) 6. 불면잠에 있어서의 태피선의 형태는 그 공포형태피선이 정상잠의 것과 크게 차이가 있어 공흉의 크기가 정상잠의 것에 비하여 몇배에 달하였다. 7. 불면잠과 정상잠과의 분필세포의 구조에는 큰 차이가 없지만 불면잠의 과립형태피선은 정상잠에 비하여 소형이 었다.

• 한국정밀공학회지
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• 제21권3호
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• pp.155-162
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• 2004

This paper presents the fabrication procedure and the experiments for the 3-axis fine positioning stage proposed in［1］. First, the dynamic characteristics of the actuator and the stage are tested with the preload changed in order to validate the stage design specifications. Secondly, the performance of the stage is also evaluated on the accuracy associated with linear positioning, angular error, and straightness error. Experimental results show that the developed stage is accurate enough to be used for nanometer positioning. Through the analysis and experiment, the developed fine positioning stage are found to have a long stroke due to the magnetically preloaded PZT actuators, the minimum motion crosstalk due to the use of a ball contact mechanism and the compact design.

• 한국동물학회지
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• 제30권3호
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• pp.248-260
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• 1987

In order to investigate the importance of the prospective mesodermal and endodermal blastomeres at 32-cell stage in the anis formation, blastomeres were deleted or transplanted into the ventrovegital site of another normal embryo. The results are as follows: When the dorsomesodermal or dorsoendodermal blastomeres were deleted, there was a substantial developmental lesion in the axis structure. However, when the ventromesodermal or ventroendodermal blastomeres were deleted, the formation of an axis structure was nearly normal. The dorsomesodermal or dorsoendodermal blastomeres which were transplanted into the ventral side of the normal 32-cell embryo caused the formation of a secondary body axis, and the capacity of the second axis induction in the dorsomesodermal blastomeres was a little higher than that in the dorsoendodermal blastomeres. These results imply that both the dorsomesodermal and dorsoendodermal blastomeres are involved in the formation of a set of dorsal body structures during early embryogenesis. As well, in order to investigate the axis inducing capacity in the early cleavage embryos, the dorsovegital blastomeres were transplanted into the ventrovegital site at 4-cell, 8-cell and 16-ceIL stage respectively. As a ruts·fIt, a second body axis was formed. Therefore, it seems that the early cleavage embryo as 4-cell stage dorsal blastomeres contain some informations necessary for the axis formation.

• 한국정밀공학회지
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• 제34권1호
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• pp.53-58
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• 2017

A fine stage is developed for the 3-DOF error compensation of a linear axis in order to improve the positioning accuracy. This stage is designed as a planar parallel mechanism, and the joints are based on a flexure hinge to achieve ultra-precise positioning. Also, the effect of Abbe's offsets between the measuring and driving coordinate systems is minimized to ensure an exact error compensation. The mode shapes of the designed stage are analyzed to verify the desired 3-DOF motions, and the workspace and displacement of a piezoelectric actuator (PZT) for compensation are analyzed using forward and inverse kinematics. The 3-DOF error of a linear axis is measured and compensated by using the developed fine stage. A marked improvement is observed compared to the results obtained without error compensation. The peak-to-valley (PV) values of the positional and rotational errors are reduced by 92.6% and 91.3%, respectively.