• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1380-1383
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• 2004

The scanning type XY stage is frequently used these days as precision positioning system in equipment for semiconductor or display element. It is requested higher velocity and more precise accuracy for higher productivity and measuring performance. The position accuracy of general stage is primarily affected by the geometric errors caused by parasitic motion of stage, misalignments such as perpendicular error, and thermal expansion of structure. In the case of scanning type stage, H type frame is usually used as base stage which is driven by two actuators such as linear motor. In the point view of scanning process, the stage is used in moving motion. Therefore, dynamic variation is added as significant position error source with other parasitic motion error. Because the scanning axis is driven by two actuators with two position detectors, 2 dimensional position errors have different characteristic compared to general tacked type XY stage. In this study 2D position error of scanning stage is analyzed by 1D heterodyne interferometer calibrator, which can measure 1D linear position error, straightness error, yaw error and pitch error, and perpendicular error. The 2D position error is evaluated by diagonal measurement (ISO230-6). The yaw error and perpendicular error are compensated on the base stage of scanning axis. And, the horizontal straightness error is compensated by cross axis compensation. And, dynamic motion error in scanning motion is analyzed.

• Journal of Plant Biology
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• v.9 no.3_4
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• pp.7-13
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• 1966

The investigation on the grassland type was conducted by the data in the previous these (Park 1963, '64, '65, '66). The results obtained are as follows; 1) I defined that the relationship between the valves of DS and the main species of the grass in Korea(Table Ⅰ) Grassland Stage ; Waste type………6 community-types Short grass type………3 community-types Pteridium type………1 community-types Tall grass type………4 community-types Sasamorpha type………1 community-types Shrubby Stage; Lespedeza type Pioneer tree type………6 species Forest Stage; Deciduous broad leave tree type………6 species Evergreen broad leaved tree type………3 species Evergreen needle leaved tree type………7 species 2) I defined; that the relationship between the valves of DS and the grassland type in Korea(Table 2). Of grassnland type, the range of valves of DS, 50-220 belongs to waste type; 130-310 short grass type; 230-640 tall grass type; 210-450 pteridium type; 510-970 sasamorpha type; 730-1450 shrubby type; 3) I decided; The succession stage centering on the Sasamorpha purpuracens in Korea(Table 3). 4) I decided the climate type and the grassland succession in Korea(Table 4).

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.203-208
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• 2001

In this paper, the pumping performance of the three-stage disk-type drag pump which works in the outlet pressure range from 4 to 0.01 Torr is studied experimentally. The rotational speed of the pump is 24,000rpm, and nitrogen is used as a test gas, The pumping characteristics of various drag pumps are investigated. The inlet pressures are measured for various outlet pressures of the test pump. The maximum compression ratios for zero throughput are measured for three-stage, two-stage BSC type, helical-type, one-stage BSC type and one-stage OSC type, respectively.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.224-229
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• 2009

A Study on the Stage Lighting Design by the Type of Performance Hall The purpose of this study is to inquire into the practice of lighting design which is changed by type of stage Proscenium Stage, Thrust Stage, Arena Stage, and Flexible Stage, which have originated from ancient Greek theatre and are still used in contemporary theatre. This studt takes a good at the practical application of lighting design to different types of stage, through which it is expected to improve the understanding of lighting as a part of performing arts and to develop the quality of stage arts. The way of lighting design by type of stage can be acstracted as the following. This is expected to be of a great help to stage arts as well as different lighting designs for each type of stage. The methodology of lighting design might have limits in its application to practice in the current war Id where theatre structures and lighting equipments are fast-developing and ever-changing. However, lighting design can develop based on the basic design concepts as the researches of all fields can develop by applying their basic theories.

• Korean Journal of Veterinary Research
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• v.26 no.2
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• pp.201-210
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• 1986

The cycle of the seminiferous epithelia in the testis of mature Korean native cattle was divided into twelve stages, using criteria the morphological changes in the acrosomic system and the nuclei of developing spematids and germ cells. The results were summarized as follows; 1. The minimum number of tripe A spermatogonia were the average of 1.8 in both at stages I and VI, while maximum numbers were the average of 4.2 at stage XII. Some type A spermatogonia divided at stage XII to produce the type intermediate(IN) spermatogonia at following stage I. The intermediate type spermatogonia divided at stage IV to produce the type B spermatogonia at stage V. 2. The type B spermatogonia divided at stage VII to produce the preleptotene primary spermatocytes at stage XII. The pachytene primary spermatocytes divided at stage XI to produce the secondary spermatocytes at stage VII. The secondary spermatocytes observed at stag XII divided to give rise to the round spermatids at following stage I. Each numbers of the first spermatocytes and of spermatids were almost constant, respectively, through the cycle of the seminiferous epitherium. 3. The relative frequencies of each stage among stages I to XII of the cycle of the seminiferous epithelia were 6.1, 3.7, 5.2, 7.8, 2.2. 3.3, 13.8, 18.4, 11.8, 7.2, 18.1% and 2.4%, respectively.

• Korean Journal of Animal Reproduction
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• v.11 no.1
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• pp.33-41
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• 1987

The cycle of the seminiferous epthelia in the testis of matured Korean Native Cattle was divided into eight stages. The results were summarized as follows: 1. Type A spermatogonia a, pp.ared twice as many at stage 2 as compared to stage 1, while maximum numbers were the average of 2.8 at stage 2. The intermediate and Type B spermatogonia were found during the stage 3 to 8, stage 6 to 8, respectively. The leptolene primary spermatocytes were not observed during the stage 5 to 7, while the pachytene primary spermatocytes were shown the least in number at stage 4, the secondary supermatocytes could be seen only at stage 4 and the round spermatids were not observed at stage 3, 4. 2. The relative frequencies of the eight stages of the cycle of the seminiferous eptithelia were 24.9, 14.2, 19.0, 6.3, 3.7, 7.9, 10.3 and 13.9%, respectively. 3. Some of the nuclei of Sertoli cells transformed from the "parallel" type to the "perpendicular" type. This evolution took place from stage 1 to 5, when the number of "perpendicular" type nuclei reached a peak and the number was decreased in the rest of the stages.sed in the rest of the stages.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.12
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• pp.88-94
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• 2007

A flexure hinge-based compliant stage driven by stack-type piezoelectric elements has high precision motion but small operational range due to the characteristics of the piezoelectric element. Since the common flexure hinges can be broken by excessive deflection when the displacement is amplified by a high amplification ratio, a flexure hinge mechanism for large deflection is required. A cartwheel-type flexure hinge has an advantage of larger deflection compared with the common flexure hinges. This study presents a rotation stage with cartwheel-type flexure hinges driven by a stack-type piezoelectric element. The characteristics and the performance of the rotation stage are described by the terms of principal resonance frequency, amplification ratio of rotational displacement, maximum rotational displacement and block moment, in which the terms are analyzed by geometric parameters of the rotation stage. The analyzed results will be used as the guideline of the design of the rotation stage.

• The Journal of Korea Robotics Society
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• v.2 no.2
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• pp.178-182
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• 2007

Precision stages are essential device for micro machines, fiber optic assembly systems, and biology instruments. In this paper, a precision inchworm type actuator for a linear stage is proposed and evaluated. An analytic method to design an inchworm type motor is proposed. Developed actuator provides fast motion compared with a commercial inchworm actuator, and can be used as an actuator for a stage in substitution for a conventional rotary actuator.

• Korean Journal of Veterinary Research
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• v.33 no.1
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• pp.23-36
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• 1993

To investigate the cycle and relative frequences and the fine structure of seminiferous epithelia in mature Jindo dogs, histologic study was performed. The results obtained were summarized as follows; 1. Type A spermatogonia appeared approximately 1.6 times as many at stage II as compared to stage I while type In spermatogonia appeared small amount in stage III, IV and V. type B spermatogonia were found during the stage VI to VIII, though not detectable during stage I to V. The type B spermatogonia divided at stage VII to produce the preleptotene primary spermatocytes at stage VIII. The number of primary spermatocytes of the leptotene phase markedly increased during stage I to II, and the primary spermatocytes of the pachytene phase were shown the least in number at stage IV. The secondary spermatocytes could be seen only at stage IV. 2. The relative frequencies of each stage from stages I to VIII of the cycle of seminiferous epithelia were 31.6, 11.9, 10.0, 3.2, 8.2, 10.1, 11.7 and 13.2% respectively. 3. On electron microscopic observations, acrosomal vesicle of spermatids appeared larger though the bulk of germ cells were the morphologically same as those of the other animal species. Thread line structures light microscopically observed in the cytoplasm of Sertoli cell were the longitudinal orientation of mitochondria.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.359-362
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• 2003

The aerostatic stage. which is used in semiconductor process, is demanded higher velocity and more precise accuracy for higher productivity and integrated performance. So, in the case of XY stage, H type structure, which is designed two co-linear axis of guide-way, driving force in one surface, has advantage of velocity and accuracy compared to conventional tacked type XY stage. To analyze characteristics of H type aerostatic stage, H type aerostatic surface XY stage is made, which is driven by linear motor and detected position with precise optical linear scale. And, analyze characteristics of motion error, effect of angular motion on positioning accuracy error and effect of simultaneous control on variation of velocity.