• 전자공학회논문지
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• 제53권8호
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• pp.39-48
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• 2016

본 논문에서는 소스와 드레인의 구조가 육각형인 FinFET에서 구조 변수 및 핀/핑거 개수 증가에 따른 열 저항 모델을 제안한다. 소자의 크기가 감소하여 발열 효과 및 열 특성의 영향이 커졌으며, 이를 분석하기 위해 소자의 열 저항은 중요한 요소이다. 열 저항 모델은 소자에서 열이 생성되는 열원과 열이 빠져나가는 contact를 설정했으며, 도메인은 열원과 4 부분의 소스, 드레인, 게이트, 서브스트레이트 contact를 통해 나누어진다. 또 각각의 contact 열 저항 모델은 TCAD의 시뮬레이션 결과의 온도 및 열 흐름을 분석하여 해석이 용이한 형태로 세분화하였다. 도메인들은 그 구조에 따라 구조 변수를 통한 적분 및 등각 매핑 방식을 기반으로 모델링하였다. 먼저 싱글 핀으로 열 저항을 분석하여 모델링하였으며, 멀티 핀/핑거의 열 저항 모델의 정확도를 높이기 위해 채널증가에 따른 파라미터의 변화를 적용하였다. 제안한 열 저항 모델은 3D Technology CAD 시뮬레이션을 해석하여 얻은 열 저항 결과와 비교하였으며, 싱글 핀 및 멀티 핀의 전체 열 저항 모델은 3 % 이하의 오차를 얻었다. 제안한 열 저항은 핀/핑거 개수의 증가에 따른 열 저항을 예측할 수 있으며, 발열효과 및 열 특성 분석을 계산하여 회로 특성을 개선할 수 있다.

• Tribology and Lubricants
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• 제15권3호
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• pp.265-271
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• 1999

Wherever there are rotating equipment and contact between surface, there is wear and the generation of wear particles. The particles contained in the lubricating oil carry detailed and important information about the condition monitoring of the machine. This information may be deduced from particle shape, composition, size distribution, and concentration. Therefore, This paper was undertaken to Ferrography system of wear debris generated from lubricated moving machine surface. The lubricating wear test was performed under different experimental conditions using the Falex wear test of Pin and V-Block type by Ti(C, N) coated. It was shown from the test results that wear particle concentration (WPC) and wear severity Index( $I_{S}$), size distribution in normal and abnormal wear have come out all the higher value by increases sliding friction time. Wear shape is observed on the Ferrogram it was discovered a thin leaf wear debris as well as ball and plate type wear particles. This kind of large wear shape have an important effect not only metals damage, but also seizure phenomenon.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.383-388
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• 2001

Effects of particle property variation of cone crack shape according to impact velocity in silicon carbide materials were investigated. The damage induced by spherical impact having different material and size was different according to materials. The size of ring cracks induced on the surface of specimen increased with increase of impact velocity within elastic contact conditions. The impact of steel particle produced larger ring cracks than that of SiC particle. In case of high impact velocity, the impact of SiC particle produced radial cracks by the elastic-plastic deformation at impact regions. Also percussion cone was formed from the back surface of specimen when particle size become large and its impact velocity exceeded a critical value. Increasing impact velocity, zenithal angle of cone cracks in SiC material was linearly decreasing not effect of impact particle size. An empirical equation, $\theta=\theta_{st}-\upsilon_p(180-\theta_{st})(\rho_p/\rho_s)^{1/2}/415$, was obtained from the test data as a function of quasi-static zenithal angle of cone crack($\theta_{st}$), the density of impact particle(${\rho}_p$) and specimen(${\rho}_s$). Applying this equation to the another materials, the variation of zenithal angle of cone crack could be predicted from the particle impact velocity.

• Journal of Preventive Medicine and Public Health
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• 제40권2호
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• pp.95-101
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• 2007

Focusing on complex diseases of public health significance, strategic issues regarding the on-going Korean Genome Cohort were reviewed: target size and diseases, measurements, study design issues, and follow-up strategy of the cohort. Considering the epidemiologic characteristics of Korean population as well as strengths and drawbacks of current research environment, we tried to tailor the experience of other existing cohorts into proposals for this Korean study. Currently 100,000 individuals have been participating the new Genome Cohort in Korea. Target size of de novo collection is recommended to be set as between 300,000 to 500,000. This target size would allow acceptable power to detect genetic and environmental factors of moderate effect size and possible interactions between them. Family units and/or special subgroups are recommended to parallel main body of adult individuals to increase the overall efficiency of the study. Given that response rate to the conventional re-contact method may not be satisfactory, successful follow-up is the main key to the achievement of the Korean Genome Cohort. Access to the central database such as National Health Insurance data can provide enormous potential for near-complete case detection. Efforts to build consensus amongst scientists from broad fields and stakeholders are crucial to unleash the centralized database as well as to refine the commitment of this national project.

• The Journal of Asian Finance, Economics and Business
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• 제7권5호
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• pp.41-50
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• 2020

The paper investigates the factors that affect the demand for a voluntary audit of small and medium-sized enterprises (SMEs) in Vietnam. A structured questionnaire survey of 284 SMEs was employed, preceded by in-depth interviews with auditors and SMEs' managers. The research used logistic regression estimator to address econometric issues and to improve the accuracy of the regression coefficients. The results show that the degree of director's view on voluntary audit, related stakeholder, degree of recommendation, and firm size have a statistically significant positive effect on audit decisions of SMEs while degree of audit fee has a statistically significant negative effect, and degree of subjective norm does not affect. This indicated that SMEs are more likely to have an external audit if they have some typical features: it is becoming larger in terms of size, and the directors consider that the audit has a relative benefit outweighing its cost. The research results suggested that Vietnam Government should make a statutory audit of SMEs' financial statements rather than make it an option for SMEs. The auditing firms were also recommended to actively take their audit services to SMEs rather than waiting for the SMEs' managers to contact them for their services.

• 한국분말재료학회지
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• 제31권2호
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• pp.132-136
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• 2024

This study investigated the effects of revolution speed and ball size in planetary milling on the microstructure and dehydrogenation behavior of TiH₂ powder. The particle size analysis showed that the large particles present in the raw powder were effectively refined as the revolution speed increased, and when milled at 500 rpm, the median particle size was 1.47 ㎛. Milling with a mixture of balls of two or three sizes was more effective in refining the raw powder than milling with balls of a single size. A mixture of 3 mm and 5 mm diameter balls was the optimal condition for particle refinement, and the measured median particle size was 0.71 ㎛. The dependence of particle size on revolution speed and ball size was explained by changes in input energy and the number of contact points of the balls. In the milled powder, the endothermic peak measured using differential thermal analysis was observed at a relatively low temperature. This finding was interpreted as the activation of a dehydrogenation reaction, mainly due to the increase in the specific surface area and the concentration of lattice defects.

• 한국주조공학회지
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• 제21권4호
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• pp.232-238
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• 2001

Experimental study on the twin roll strip casting of BCuP-5(Cu-15wt%Ag-wt5%P) alloy was carried out using laboratory scale horizontal type twin roll caster. In this study, among the various operating parameters, such as tundish angle, contact angle, pouring temperature, roll speed, presetting gap of the rolls and kinds of roll and tundish materials, effect of pouring temperature for strip casting of BCuP-5 alloy which has long freezing range of about $170^{\circ}C$ was mainly investigated. BCuP-5 alloy strip was successfully produced when pouring molten metal at lower temperature than its liquidus temperature. Microstructure of the cast strip consists of primary Cu and eutectic. Especially the size of primary Cu phase increased with decreasing of pouring temperature.

• 대한기계학회논문집
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• 제13권4호
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• pp.726-733
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• 1989

본 연구에서는 전력 다이오드 칩이 방산판에 부착되어 있는 형상을 기준하여 열전달 모형을 설정하고 해석적 해가 존재하는 단수형상으로 이상화하여 국부적 온도 상승을 일으키는 조건을 파악하고 실제형상의 모형에 대하여 유한요소해석에 의한 온도분포 계산결과를 제시한다.또한 발열체가 인접해 있는 경우에 대한 온도 집중 현상의 결과도 아울러 검토한다.

• 패션비즈니스
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• 제18권2호
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• pp.54-65
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• 2014

This study developed basic pattern for competition figure skating wear for school girls. Figure skating wears are difficult for making basic patterns based on standard size chart, because girls' body size are slimmer and more slender compared to the general girl's and the competition wears such as, swim suit with sleeves are, closely in contact with the player's body. The competition wears for school girl was made with consideration of changing of the body shape, physical exercises, and various specificities according to stretch material. To raise artistic effect while doing beautiful motions, and to assist in facile technique motions, competition wears need to have enough ease on the side line from waist to armpit, from armpit to wrist, and in trunk girth including crotch girth. Also, to stand out in beauty, a costume designing has a proper skirt position, length, flare width, and a tight bodice according to the player's body proportion. Most of the customers are displeased at the high price, unfitness of size, insufficient design, and difficulty in access, since they are not sold in sporting goods store. Therefore, a competition wear's basic pattern was made through scientific and emotional process including concerns on material properties, room for activities, and ideal body proportion. Systemizing the basic patterns of production method will solve high repairing expenses, unsuitable sizing, and improve accessibility for purchase.

• Macromolecular Research
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• 제8권1호
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• pp.6-11
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• 2000

In this study, we examined the charging behavior of chopped carbon fibers during electro-flocking process, which is one of the key processes of the novel technique for fabricating conductive polymer composite films. Short carbon fibers (CF) during electroflocking were electrically charged by the combined effect of contact charging, corona charging and tribocharging. The specific charge built on CF surface was measured by using Faraday cup method. Specific charge increased not only with increasing electric field strength and potential impressed to mesh electrode as expected from theoretical considerations in literature, but with decreasing mesh opening size due to the improved contact charging condition. However, CF length was found unexpectedly to influence the amount of CF specific charge due to the agglomerated nature of CF flocks leading to the change in charging conditions.