• 한국정밀공학회지
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• 제28권1호
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• pp.96-101
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• 2011

Under extreme test or operation condition, refrigerator endures complicated stresses state and thermal bowing deformation arises on the sidewall. Shelf rails designed in the inner case provide increased surface area to permit expansion without bowing, and also increase structural rigidity to resist bowing. In this study, we designed six different shelf patterns of refrigerator model and studied the bead on refrigerator deformation using finite element method (FEM). Analysis result shows that increasing the numbers of beads properly in refrigerator is more helpful to reduce thermal bowing deformation. In addition, the beads would decrease stress on refrigerator sidewall. However, vertical beads have no effect to reduce thermal deformation of the bowing.

• 대한후두음성언어의학회지
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• 제16권1호
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• pp.68-75
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• 2005

The treatment of sulcus vocalis and vocal bowing has been commonly used Thyroplasty Type surgery or injection within vocal folds such as Teflon, silicone, collagen. However, and treatment has not been acquired satisfactory treatment effect. This study was conducted to demonstrate voice therapy effect using singer's vocal technique and respiratory training. 4 patients (1 male, 3 females) with sulcus vocalis or bowing, with or without scar were selected for this study and we compared with acoustic, aerodynamic measures and stroboscopy observation before and after voice therapy. The results showed that 1) case 1 (48yr, male) with sulcus vocalis decreased F0 (Fundamental Frequency), increase CQ(Close Quotient) and high degree of satisfaction but not improved voice quality after voice therapy. 2) case 2(19yrs, femal) with mild sulcus vocalis improved as normal voice quality after voice therapy. 3) case 3(38yrs, female) with functional bowing showed abnormalvocal contact before therapy whereas CQ was increased after voice therapy. 4) case 4(27yrs, female) with vocal atrophy and vocal bowing changed normal range of Fo and increased CQ after voice therapy. Even though contact area of both vocal folds was increased and lowered F0 after voice therapy, current outcomes revealed that normal voice quality was not regained. These results might signify that it was difficult that vocal folds couldn't be recovery of symmetry and viscoelastic property of mucosal wave through voice therapy. However, it was difficult for this study to maintain voice therapy so that evaluate effect of voice therapy for long-term. Further study will be needed to long-term follow-up for voice therapy with these patients.

• 대한후두음성언어의학회지
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• 제14권2호
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• pp.94-97
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• 2003

Background and Objectives : Bowing of the vocal fold, a bowed edge of the vocal fold results from various disorder causes glottic incompetence resulting in voice disorders. The results of treatment were not satisfactory even though a variety of methods of treatment were applied. The goal of this study is to evaluate of efficacy of the non-surgical, voice therapy in patients with vocal fold bowing. Materials and Method : Twenty two patients of vocal fold bowing not resulting from vocal fold palsy and sulcus vocalis were analyzed. After voice therapy and medical treatment, parameters of perceptual, acoustic, aerodynamic analysis and stroboscopic findings were compared those of pretreatment results. Results and Conclusion : Jitter, shimmer and maximal phonation time were significantly improved and subjective satisfaction was improved in 73% of patients. In the videostroboscopic examination, vocal fold gap was decreased in 27% of patents. The result of this study indicates that voice therapy alone has effect in treatment of vocal fold bowing. Voice therapy is one of the mainstay of treatment of vocal fold bowing.

• 한국재료학회지
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• 제25권1호
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• pp.16-20
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• 2015

In this study, in order to improve the efficiency of n-type monocrystalline solar cells with an Alu-cell structure, we investigate the effect of the amount of Al paste in thin n-type monocrystalline wafers with thicknesses of $120{\mu}m$, $130{\mu}m$, $140{\mu}m$. Formation of the Al doped $p^+$ layer and wafer bowing occurred from the formation process of the Al back electrode was analyzed. Changing the amount of Al paste increased the thickness of the Al doped $p^+$ layer, and sheet resistivity decreased; however, wafer bowing increased due to the thermal expansion coefficient between the Al paste and the c-Si wafer. With the application of $5.34mg/cm^2$ of Al paste, wafer bowing in a thickness of $140{\mu}m$ reached a maximum of 2.9 mm and wafer bowing in a thickness of $120{\mu}m$ reached a maximum of 4 mm. The study's results suggest that when considering uniformity and thickness of an Al doped $p^+$ layer, sheet resistivity, and wafer bowing, the appropriate amount of Al paste for formation of the Al back electrode is $4.72mg/cm^2$ in a wafer with a thickness of $120{\mu}m$.

• 한국전기전자재료학회논문지
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• 제28권12호
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• pp.776-780
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• 2015

In this paper, we have studied the effect of mechanical polishing to Ga-polar face for reducing the wafer bowing and strain in free-standing GaN. After the mechanical polishing to Ga-polar face, the bowing of the free-standing GaN substrate significantly decreased with increasing the size of diamond slurry, and eventually changed the bowing direction from concave to convex. Furthermore, the full width at half maximum (FWHM) of high-resolution X-ray diffraction (HR-XRD) were decreased, especially the FWHM of (1 0 2) reflection for $1.0{\mu}m$ size of diamond slurry was significantly decreased from 630 to 203 arcsec. In the case, we confirmed that the compressive strain in Ga-polar face was fully released by Raman measurement.

• 한국전기전자재료학회논문지
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• 제29권1호
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• pp.30-34
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• 2016

In this paper, we report that selective etching on N-polar face by EC (electro-chemical)-etching effect on the reduction of bowing and strain of FS (free-standing)-GaN substrates. We applied the EC-etching to concave and convex type of FS-GaN substrates. After the EC-etching for FS-GaN, nano porous structure was formed on N-polar face of concave and convex type of FS-GaN. Consequently, the bowing in the convex type of FS-GaN substrate was decreased but the bowing in the concave type of FS-GaN substrate was increased. Furthermore, the FWHM (full width at half maximum) of (1 0 2) reflection for the convex type of FS-GaN was significantly decreased from 601 to 259 arcsec. In the case, we confirmed that the EC-etching method was very effective to reduce the bowing in the convex type of FS-GaN and the compressive stress in N-polar face of convex type of FS-GaN was fully released by Raman measurement.

• 한국구조물진단유지관리공학회 논문집
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• 제10권2호
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• pp.123-133
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• 2006

본 연구의 목적은 다단계 동적계획법 및 축차무제약 최소화기법을 이용하여 강접 및 다양한 반강접 접합부 모델을 가진 뼈대 구조물의 최적화 알고리즘을 개발하는데 있다. Bowing effect를 고려한 비선형 보-기둥이론을 사용하였으며, 보-기둥의 접합부는 반강접접합부인 양면 복부앵글을 가진 접합부, 상 하플랜지 접합부, 양면복부앵글을 가진 상 하플랜지 접합부를 고려하여 연구를 수행하였으며, 각 접합부의 해석모델은 수정된 지수모델, 다항식 모델, 파워모델을 사용하였다. 최적화문제에 있어서 목적함수는 강재의 중량을 취하였으며, 설계변수는 부재의 단면치수를 선택하였다. 설계제약조건은 축력, 전단력 및 휨모멘트의 저항성과 사용성에 대해 수식화하였다. 본 연구에서 개발된 기하학적 비선형을 고려한 2차 탄성해석법을 이용하여 강접 및 다양한 모델을 가진 반강접 강뼈대 구조물의 종합적인 연속 최적설계 프로그램을 개발하였다.

• 한국전자통신학회논문지
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• 제13권6호
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• pp.1213-1222
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• 2018

본 연구에서는 무질서 효과가 고려된, 새로이 가정한 가상 결정 근사법을 갖는 empirical pseudopotential method를 사용하여 온도와 조성비 변화에 따른 3원계 질화물계 화합물 반도체 $GaAs_{1-X}N_X$의 휨 매개변수 및 에너지 밴드갭을 계산하였다. 300K의 조성비 구간($0{\leq}x{\leq}0.05$)에서 에너지 밴드갭들이 급격히 감소하며, 해당하는 계산된 휨 매개변수가 15eV임을 알 수 있었다. 에너지 밴드갭 계산 결과로부터 굴절률 n과 고주파 유전상수 ${\varepsilon}$ 등의 광학상수를 계산하였고, 에너지 밴드갭 계산 결과는 실험치를 대체로 잘 설명하였다.

• 한국전자통신학회논문지
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• 제12권5호
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• pp.783-790
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• 2017

본 연구에서는 무질서 효과가 고려된, 새로이 가정한 가상 결정 근사법을 갖는 empirical pseudopotential method를 사용하여 온도와 조성비 변화에 따른 3원계 질화물계 화합물 반도체 GaP1-xNx의 휨 매개변수 및 에너지 밴드갭을 계산하였다. 300K의 조성비 구간($0{\leq}x{\leq}0.05$)에서 에너지 밴드갭들이 급격히 감소하며, 해당하는 계산된 휨 매개변수가 13.1eV임을 알 수 있었다. 에너지 밴드갭 계산 결과로부터 굴절률 n과 실수부 유전상수 함수 ${\varepsilon}$를 계산하였고, 에너지 밴드갭 계산 결과는 실험치를 대체로 잘 설명하였다.

• 한국전자통신학회논문지
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• 제11권12호
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• pp.1165-1174
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• 2016

본 연구에서는 무질서 효과가 고려된, 새로이 가정한 가상 결정 근사법 내의 Empirical Pseudopotential Method(EPM)를 사용하여 3원계 질화물계 화합물 반도체 InAs1-xNx의 휨 매개변수 및 에너지 밴드갭을 계산하였다. InAs1-xNx 조성비 구간($0{\leq}x{\leq}0.05$)에서 계산된 휨 매개변수는 4.1eV를 갖으며, 해당되는 에너지 밴드갭들이 급격히 감소하고 있음을 알 수 있었다. EPM에 의한 계산 결과를 온도와 조성비를 고려한 수정된 Band Anti-Crossing(BAC) 모델에 적용하여 질화물계 화합물 반도체 InAs1-xNx의 에너지 띠구조를 계산하였다. 또한 InAs1-xNx의 결합 상수 CMN=1.8 등을 결정할 수 있었으며, 계산결과는 실험치를 대체로 잘 설명할 수 있었다.