• Transactions of Materials Processing
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• v.32 no.1
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• pp.35-40
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• 2023

In the case of a wire with a very fine diameter during the multi-stage drawing process, the heterogeneity of the deformation in the radial direction tends to develop strongly as the amount of deformation is accumulated. It is known that the heterogeneity of deformation in the radial direction of the wire is closely related to the process parameters during the multi-stage drawing process. In this study, finite element analysis (FEA) was used to theoretically examine the effect of friction between the surface of the wire and the drawing die during the multi-stage drawing process of Cu-0.2wt%Mg alloy on the deformation heterogeneity developed in the radial direction of the wire. The distribution of effective strain, radial strain, circumferential strain, and shear strain developed in the radial direction of the wire during the multi-stage drawing process was analyzed while changing the friction coefficient, and the results were analyzed and compared for each path and position. The FEA results revealed that the shear strain developed in the radial direction of the wire during the multi-stage drawing process of Cu-0.2wt%Mg alloy showed the most non-uniform distribution and was also severely affected by the friction coefficient.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.207-209
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• 2000

In this paper, we developed a feature point detection algorithm that detects upstroke point(S), peak point(P), incisura(C) point from radial pulse waveform which obtained by using the developed radial pulse transducer. As the results of experiment the three kinds of parameters can extracted with effectively from normal radial pulse waveform.

• Advances in Computational Design
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• v.3 no.3
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• pp.303-318
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• 2018

This article presents a semi-analytical solution for an exponentially graded piezoelectric hollow sphere. The sphere interacts with electric displacement, elastic deformations, electric potentials, magneto-thermo-elasticity, and hygrothermal influences. The hollow sphere may be standing under both mechanical and electric potentials. Electro-magneto-elastic behavior of magnetic field vector can be described in the hollow sphere. All material, thermal and magnetic properties of hollow sphere are supposed to be graded in radial direction. A semi-analytical technique is improved to deduce all fields in which different boundary conditions for radial stress and electric potential are presented. Numerical examples for radial displacement, radial and hoop stresses, and electric potential are investigated. The influence of many parameters is studied. It is seen that the gradation of all material, thermal and magnetic properties has particular effectiveness in many applications of modern technology.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.2
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• pp.26-33
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• 2005

In this paper, the tube forming by radial-forward extrusion is analyzed by numerical simulation and experiments. The paper discusses the effect of process variables such as gap height, relative gap width and die comer radius on tube forming. The influence of deformation patterns of flange in radial extrusion on forward extrusion for tube forming is investigated and summarized in terms of the maximum forming force and hardness variations along the extrusion path. Furthermore the external defects are shown experimentally during the forming operation. Based on finite element analysis in conjunction with experimental test in Al alloy, analysis is performed for important parameter combination in order to reduce forming defects. Eventually, the process parameters for safe forming are suggested in order to reduce the forming defects.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.2
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• pp.76-83
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• 1993

The vibration characteristics of radial tire are studied. In order to obtain theoretical natural frequency and mode shape, the plane vibration of a tire is modeled to that of circular beam. By using the Tielking method based on Hamilton's principle, theoretical results are determined by considering tension force due to tire inflation pressure, rotational velocity and tangential, radial stiffness. Modal parameters varying the inflation pressure are determined experimentally by using the transfer function method. Results show that material property and wear are parameter for shifting of natural frequency and damping.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.12
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• pp.168-175
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• 2003

In this paper, the tube forming by radial-forward extrusion is analyzed by numerical simulation and experiments. The paper discusses the effects of process variables such as gap height, relative gap width and die corner radius on tube forming. The influence of deformation patterns of flange in radial extrusion on forward extrusion for tube forming is investigated and summarized in terms of the maximum forming force and hardness variations along the extrusion path. Furthermore the external defects are shown experimentally during the forming operation. Based on finite element analysis in conjunction with experimental test in Al alloy, analysis is performed for important parameter combination in order to reduce forming defects. Eventually, the process parameters for safe forming are suggested in order to reduce the forming defects.

• Journal of Acupuncture Research
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• v.33 no.3
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• pp.45-66
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• 2016

Objectives : The purpose of this study is to find parameters to compare the effects of Sa-Am acupuncture with gall bladder jeonggyeok and seunggyeok on radial pulse in healthy subjects. Methods : 60 healthy subjects participated in this study and divided into the gall bladder jeonggyeok group (GB+ group), the gall bladder seunggyeok group (GB- group) and the control group. Radial pulse was measured by a 3 dimensional pulse imaging system (DMP-3000) before, immediately after, 30 minutes after and 60 minutes after acupuncture on the Cun, Guan and Chi in the GB+, GB- group and at the same time for the control group. Results : 1. The GB+ and GB- group exhibited significantly increased T, M4/M1 and decreased T1/T, T2/T, T5/T, M1, M2 compared to the control group. 2. The GB+ and GB- group exhibited significantly increased H4, Ad/Ap, RAI/HR and decreased As/Ap, Aw/Ap in the right Guan and decreased pulse power volume/min in the left Guan compared to the control group. 3. The GB- group exhibited significantly decreased M3, M3/M1 and increased M4/M1, M5, M5/M1 compared to the GB+ group. The GB+ group exhibited significantly decreased T4/(T-T4) compared to the GB- group. 4. The GB- group exhibited significantly decreased H1 in the right Guan, Chi, H4, pulse area in the right Chi, H5, pulse power volume/min in the left Chi, right Chi, and increased main peak angle in the right Guan, Chi compared to the GB+ group. Conclusion : The effect of gall bladder jeonggyeok and seunggyeok in healthy humans may be observed on various parameters. The parameters analyzed in this study may be used to differentiate effects between gall bladder jeonggyeok and seunggyeok on radial pulse. Further studies on the effects of Sa-Am acupuncture using radial pulse are needed.

• Journal of Convergence Korean Medicine
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• v.6 no.1
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• pp.5-20
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• 2024

Objectives: This study was aimed to evaluate the hemodynamic feasibility using pulse parameters as a way to establish safe dose guidelines for Chunwangbosim-dan, and to provide a foundation for developing evidence-based guidelines for clinical use. Methods: Forty-one volunteers were recruited to participate in a study examining the changes in pulse wave characteristics following the ingestion of Chunwangbosim-dan, over a period of 2 weeks, and pulse wave measurements were taken before and after the administration. Pulse wave parameters were measured in this study using a 3-dimensional radial pulse tonometry device(DMP-Lifeplus). In addition, questionnaire, blood pressure, temperature, and body composition were also measured as secondary measures. Results: Fifteen minutes after administration of Chunwangbosim-dan, the non-adverse event group(non-AE) exhibited a statistically significant increase in several power and pressure-related parameters, including h1, h3, h4, h5, SA, PA and PW, while the adverse event group(AE) showed a trend of decreasing stroke volume and increasing Systemic Vascular Resistance Index(SVRI) and applied pressure. After 2 weeks of administration, non-adverse event group(non-AE) exhibited significant changes in standard deviation of pulse rate and HRV_LH ratio. Notably, there are significant differences between AE group and non-AE group in h4/h1, w/t, applied pressure, SV and pulse rate. Conclusion: These findings suggest that pulse parameters may be a useful way to establish safe dosing guidelines for Chunwangbosim-dan. Further research is needed to confirm these results and to develop evidence-based guidelines for clinical use.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.28.3-28.3
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• 2011

Halo coronal mass ejections (HCMEs) are mainly responsible for the most severe geomagnetic storms. To minimize the projection effect of the HCMEs observed by coronagraphs, several cone models have been suggested. These models allow us to determine the geometrical and kinematic parameters of HCMEs : radial speed, source location, angular width, and the angle between the central axis of the cone and the plane of the sky. In this study, we compare these parameters form two representative cone models (the ice-cream cone model and the asymmetric cone model) using well-observed HCMEs from 2001 to 2002. And we obtain the root mean square error (rms error) between observed projection speeds and calculated projection speeds for both cone models. It is found that the average rms speed error (89 km/s) of the asymmetric cone model is a little smaller than that (107 km/s) of the ice-cream cone models, implying that the radial speeds from both models are reasonably estimated. We also find that the radial speeds obtained from two models are similar to each other with the correlation coefficient of about 0.8.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.980-986
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• 2003

As the ultra precision grinding can be applied to wafering process by the refinement of the abrasive, the development of high stiffness equipment and grinding skill, the conventional wafering process which consists of lapping, etching, Ist, 2nd and 3rd polishing could be exchanged to the new process which consists of precision surface grinding, final polishing and post cleaning. Especially, the ultra precision grinding of wafer improves the flatness of wafer and the efficiency of production. Futhermore, it has been not only used in bare wafer grinding, but also applied to wafer back grinding and SOI wafer grinding. This paper focused on the effect of the wheel path density and relative velocity on the characteristic of ground wafer in in-feed grinding with cup-wheel. It seems that the variation of the parameters in radial direction of wafer results in the non-uniform surface quality over the wafer. So, in this paper, the geometric analysis on grinding process is carried out, and then, the effect of the parameters on wafer surface quality is evaluated