• Clinical and Experimental Reproductive Medicine
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• 제13권1호
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• pp.39-51
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• 1986

This experiment has been done to evaluate the relationship between the follicular atresia and the protein patterns on electrophoreais of the follicular fluids in porcine ovary. The protein concentration of the follicular fluids was lower than that of serum, and gradually decreased as the follicle siae became larger. The number of protein bands of follicular fluid on electrophoresis was less than that of serum, and gradually increased as follicle size became larger. Three specific bands were detected on disc PAGE and one band(M W. 75,000) on SDS PAGE in the follicular fluids, while not in serum. One band (A) at ${\beta}$-globulin region on disc PAGE became heavier, as follicles became atretic. Two bands less than(M. W. 20,000) were detected only in the large follicular fluid. Another band(M. W. 43,000) was not detected in necrotic group, whereas all other groups showed it. It could be concluded that the component and composition of the proteins follicular fluids changes according to the follicular size during atresia. Therefore detection of the changing pattern of proteins in the follicular fluid can be used as a basic criterion for the identification of follicular atretic stage.

• 한국통신학회논문지
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• 제18권10호
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• pp.1495-1507
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• 1993

본 논문에서 마이크로프로그램 제어방식을 이용하여 CDP(Compact Disc Player)에서 사용되는 RS 부호(Reed-Solomon code)의 복호기를 설계하였다. 사용한 복호방법은 Newton 항등식들로 부터 얻어진 연립방정식들을 이용하여 오류위치다항식의 계수들을 구하고, C2(외부호)복호에서의 소실데이타 개수를 확인한다. 또한 C2복호에서 소실데이타 값들을 C1(내부호)복호 결과와 신드롬들을 이용하여 구한다. 이와 같은 복호방법을 이용하여 4개의 소실정정까지 할 수 있도록 해서 오류정정능력을 높였다. 설계한 복호기는 오류정정에 필요한 GF(28)상에서 연산을 수행할 수 있는 복호연산기와 프로그램 ROM을 가지고있는 복호제어기 띤 마이크로명령어(microinstruction)들로 구성된다. 마이크로명령어들을 이용하여 RS부호의 복호 알고리즘을 프로그램할 수 있으며, 성능향상이나 다른 용도에 사용하기 위해서는 프로그램 ROM만 바꾸면 가능하므로 간편하다. 본 논문에서 설계한 복호기는 Verilog HDL의 Logic Level Modeling을 이용하여 구현했으며, 설계된 복호기에서 각 마이크로명명령어들은 14비트(=1 word)이고, 프로그램 ROM의 크기는 360 word이다. 또한 C1과 C2를 모두 복호하는데 걸리는 최대시간은 424 clock-cycle이다.

• Restorative Dentistry and Endodontics
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• 제28권6호
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• pp.457-466
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• 2003

The aim of study was to investigate the effect of flow, specimen geometry and adhesion on the measurement of linear polymerization shrinkage of light cured composite resins using linear shrinkage measuring device. Four commercially available composites - an anterior posterior hybrid composite Z100, a posterior packable composite P60 and two flowable composites, Filtek flow and Tetric flow-were studied. The linear polymerization shrinkage of composites was determined using 'bonded disc method' and 'non-bond-ed' free shrinkage method at varying C-factor in the range of 1∼8 by changing specimen geometry. These measured linear shrinkage values were compared with free volumetric shrinkage values. The viscosity and flow of composites were determined and compared by measuring the dropping speed of metal rod under constant load. In non-bonded method, the linear shrinkage approximated one third of true volumetric shrink-age by isotropic contraction. However, in bonded disc method, as the bonded surface increased the linear shrinkage increased up to volumetric shrinkage value by anisotropic contraction. The linear shrinkage value increased with increasing C-factor and approximated true volumetric shrinkage and reached plateau at about C-factor 5∼6. The more flow the composite was, reduced linear shrinkage was measured by compensation radial flow.

• 대한인간공학회지
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• 제33권4호
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• pp.267-279
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• 2014

Objective: The objective of this study was to define the Dynamic Sitting (DS) through trend analysis and research on the Dynamic Chair (DC) and applied technologies. Background: The effects of changing posture on the human body have been studied to find out healthy sitting postures. It is believed that changing posture is effective in reducing disc pressure on spinal cord and preventing back pain and musculoskeletal disease. But, the definition of DS and trends of DC have not been researched yet. Therefore, trend analysis of DC and its applied technologies are required to define dynamic sitting posture. Method: We researched the type of occupant postures from previous studies. And then, sitting behaviors were classified into three types; (1) sitting and standing, (2) working and studying, (3) taking a rest. Results: Variety shapes of DC and applied technologies were found out. From the result, the trend of DC and applied technology were summarized from three perspectives. ; (1) changing the chair functions according to user's intention, (2) conversion of dynamic chair technologies to office chair mechanism, (3) enables the user to change their sitting posture without operating control device. Conclusion: From this study, we defined dynamic sitting posture and analyzed the trend of DC and its applied technologies. This result might be used to develop an office chair for healthy sitting. But further investigation is required to figure out the technologies and functions for development of healthy chair. Application: The results of the publishing trend analysis might help to determine design concept of office chair.

• International Journal of Precision Engineering and Manufacturing
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• 제2권2호
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• pp.17-25
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• 2001

In this paper, a theoretical study has been made to reduce the residual stress and birefringence in the injection-molded parts. An optimization program has been used to minimize the residual stresses and birefringence calculated from a simulation program. The thermally induced stress has been calculated using a linear viscoelasticity model. The flow stress and birefringence has been calculated using the Leonov's viscoelasticity model. This has been applied to the injection molding of a circular disc and a plate. the optimization has been done either by changing process variables while maintaining the mold temperature constant or by varying the mold-wall temperature with time. This study shows the significant reduction in residual stress and birefringence is possible through the optimization of processing conditions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.181-185
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• 2001

This paper deals with the dynamic stability of a disc brake pad taking into account of its shear deformation and rotary inertia. A brake pad can be modeled as a beam like model subjected to distributed friction forces and having two translational springs. The study of this model is intended to provide a fundamental understanding of dynamic stability of drum brake pad. Governing equations of motion are derived from extended Hamilton's principle and their corresponding numerical solutions are obtained by applying the finite element formulation. The critical distributed friction force and the instability types are investigated bt changing two translational spring constants, rotary inertia parameter and shear deformation parameter. Also, the changes of eigen-frequencies of a beam determining instability types are investigated for various combinations of two translational spring constants.

• 한국터널지하공간학회 논문집
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• 제10권1호
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• pp.81-90
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• 2008

TBM 장비에서 최적의 커터간격을 결정하는 것은 매우 중요하다. 실제로 이러한 최적 커터간격은 커터간격을 변화시켜가며 수 회의 선형절삭시험(LCM시험)을 수행하여 이를 통해 얻어진 절삭 비에너지를 비교함으로써 도출될 수 있다. 본 연구에서는 AUTODYN-3D를 이용하여 실제 선형절삭시험을 수행하지 아니하더라도 최적 커터간격을 예측할 수 있는 수치해석적 기법을 제시하였으며, 본 기법을 황등화강암에 적용하여 최적 커터간격을 예측하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.792-798
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• 2012

This study shows the vibration characteristics of an actuator with six wire-suspensions, used in optical pickups of optical disc drives (ODDs). In this paper, the vibration characteristics of this beam structure is induced mathematically. To obtain vibration modes of focusing direction, the vibration analysis is achieved in lateral and longitudinal directions of the structure. The accuracy of induced vibration characteristics is proved by comparing mode frequencies with a finite element analysis. Finally, it is shown that mode shapes can be modified by changing design parameters in mathematical expressions.

• 한국소음진동공학회논문집
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• 제22권11호
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• pp.1128-1136
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• 2012

This paper analyzes the vibration characteristics of an optical pickup actuator, which has six wire-suspensions and is used in optical disc drives(ODDs). The vibration characteristics of the actuator is mathematically described by analyzing its beam configuration and motion condition confined to lateral and longitudinal directions of the beams. The accuracy of the vibration characteristics is proved by comparing mode frequencies with a finite element analysis. Finally, it is shown that mode frequencies and shapes can be modified by changing design parameters in mathematical expressions.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1002-1003
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• 2006

This research mainly focuses on the development of sinter brazing technology for improving the process related to belt pulley made by sinter hardening. As the machine process of belt pulley takes up more than half of the total manufacturing hours, we propose changing the process to pulley groove brazed and bonded with pulley disc by applying sinter brazing to belt pulley. With the new process, the belt pulley is expected to reduce manufacturing cost to 70% of the original process by applying the sinter brazing technology; and the belt pulley bound by sinter brazing only loses 10% bonding strength compared with the original process.