• 소성∙가공
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• 제28권5호
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• pp.275-280
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• 2019

The aim of this study is to fabricate an ultra-fine pure rhodium wire using multi-pass wire drawing process. To manufacture $30{\mu}m$ ultra-fine rhodium wire from the initial $50{\mu}m$ wire, a multi-pass wire drawing process was designed based on the uniform reduction ratio theory. The elastic-plastic finite element analysis was then conducted to validate the efficacy of the designed process. The drawing load, drawing stress, and the distribution of the effective strain were evaluated using the finite element analysis. Finally, the wire drawing experiment was performed to validate the designed wire drawing process. From the results of the experiment, the diameter of the final drawn wire was found to be $29.85{\mu}m$.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.322-327
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• 1997

This paper investigates the effects of shot peening on mechanical properties of SAE 9254, which is a spring steel used for the suspension system of automobiles. Rotary Bending Fatigue test is accomplished and the results are summarized as fellows : 1. The tensile strength and the hardness do not change so much. 2. The layer of highly residual stress is obtained by multi-stage shot peening. 3. The fatigue strength seems to be improved by residual stress. 4. The fatigue strength of un-peened and multistage shot peened material are 425 MPa and 756 MPa, respectively.

• 한국정밀공학회지
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• 제26권12호
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• pp.23-31
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• 2009

• 디지털융복합연구
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• 제12권4호
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• pp.33-41
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• 2014

본 연구는 다문화가족 청소년 212명을 대상으로 Heater의 이론을 적용하여 그들의 차별경험과 문화변용스트레스 수준을 측정하였고, 이것이 국민정체성에 미치는 영향을 살펴보았다. 본 연구의 주요결과는 다음과 같다. 첫째, 조사대상자들의 차별경험을 측정한 결과 2.63(SD=.72)으로 나타나 보통수준보다 다소 높은 것으로 조사되었으며, 그들의 문화변용스트레스는 2.48(SD=.65)로 나타나 보통수준인 것으로 조사되었다. 둘째, 조사대상자의 국민정체성 수준은 2.16(SD=.57)로 조사되어 보통수준보다 낮은 것으로 나타났으며, 학업수준, 동거부모 형태, 모 한국어능력에 따라 집단별로 유의미한 차이가 나타났다. 셋째, 조사대상자의 차별경험(${\beta}$=-.305), 동거부모 형태(${\beta}$=.286), 문화변용스트레스(${\beta}$=-.225), 학업수준(${\beta}$=.186), 모 한국어 능력(${\beta}$=.173) 등의 순서로 국민정체성에 영향을 미치는 것으로 나타났다. 이러한 연구결과에 기초하여 다문화가족 청소년의 국민정체성을 향상할 수 있는 몇 가지 방안을 제시하였다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제15권2호
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• pp.124-130
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• 2015

A stress-strength analysis is used to assess the reliability of a multi-pulse rocket motor system. Main stress is found to be thermal during explosion and the distribution is obtained by simulation. The strength distribution is derived from the results of actual specimen tests. The failure rate of barrier type pulse separation device is estimated.

• Transactions on Electrical and Electronic Materials
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• 제16권4호
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• pp.173-178
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• 2015

In lieu of the excellent radio frequency (RF) performance of microelectromechanical system ( MEMS) switches, these micro switches need higher actuation voltage for their operation. This requirement is secondary to concerns over the swtiches’ reliability. This paper reports high reliability operation of RF MEMS switches with low voltage requirements. The proposed switch is optimised to perform in the Q-band, which results in actuation voltage of just 16.4 V. The mechanical stress gradient in the thin micro membrane is computed by simulating von Mises stress in a multi-physics environment that results in 90.4 MPa stress. The computed spring constant for the membrane is 3.02 N/m. The switch results in excellent RF performance with simulated isolation of above 38 dB, insertion loss of less than 0.35 dB and return loss of above 30 dB in the Q-band.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.289-292
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• 2007

To prevent the damage of glass lens molds and deterioration of glass lenses using in progressive GMP process, a thermal stress and a deformation of the glass lens molds at forming temperature should be considered in the design step. In this study, as a fundamental study to develop a multi cavity mold used in an aspheric glass lens molding, a heat transfer and a thermal stress analysis were carried out for the case of one cavity glass lens mold used in progressive GMP process. Finally, using analysis results, we estimated the thermal stress in a glass lens mold and predicted a modified height of guide ring that determines the forming height of a glass lens.

• International Journal of Advanced Culture Technology
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• 제10권4호
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• pp.245-254
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• 2022

This study is a study to empirically verify the mediating effect on college life adaptation and career preparation behavior of college students. The purpose of this study is to empirically analyze the multi-mediated effects of major satisfaction, job stress, and self-directed learning. For this study, 216 university students were enrolled. For the collected data, SPSS Process macro was used. The result is as follows. First, there were multiple parallel mediating effects and multiple serial mediating effects on major satisfaction, job stress, and self-directed learning between college life adaptability and career preparation behavior. Second, the path of simple mediation and double mediation effect was found between college life adaptation and career preparation behavior. Based on the research, the necessity of revitalizing the program for revitalization of teaching activities and industry-academic cooperation activities in the major field and improvement of career preparation behavior and university life adaptation ability and follow-up research were suggested.

• 한국의류산업학회지
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• 제5권3호
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• pp.295-298
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• 2003

The study investigated the effect of multi-functional fabric on the autonomic nervous function and psychological variables of 20 students. The experimental group exhibited lower values in anxiety, depression, fatigue and stress level and higher emotional level. This study reveals that multi-functional fabrics reduced the low frequency/high frequency power ratio of heart rate variability. These results support the multi-functional fabrics increases cardiac parasympathetic tone. In addition, experimental group were found to have lower heart rate compared with controls. This augmented heart rate in experiment provides support for stablizing autonomic nervous system. In conclusion, multi-functional fabrics may stabilize the autonomic nervous system and psychological symptoms.

• 대한기계학회논문집A
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• 제29권2호
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• pp.284-292
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• 2005

Material flaws in the from of pre-existing defects can severely affect the crack initiation. Stress distribution and crack initiation life of engineering materials such as monolithic aluminum alloy and Al/Glass fiber laminate may be different according to the defect location. The aim of this study is to evaluate effects of relative location of defects around the circular hole in monolithic aluminum and Al/Glass fiber laminates under cyclic bending moment. Stress distribution and crack initiation behavior near a circular hole are considered. Results of Finite Element (FE) model indicated the features of different stress field due to the relative defects positions. Especially, the defects positions at ${\theta}=0^{\circ}\;and\;{\theta}=30^{\circ}$ was strongly effective in stress concentration factor ($K_t$) and crack initiation behavior.