• 한국정밀공학회지
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• 제20권2호
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• pp.76-84
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• 2003

Stereolithography is the technique using a laser beam to cure a liquid resin, a photopolymer, with three dimensional computer-aided design (CAD) data. The build parameters of stereolithography such as beam size, scan velocity. hatch spacing, layer thickness and etc. are determined by the accuracy of prototype, the build time and the cured properties of the resin. In particular, beam size is important processing parameter fur the other parameters. Therefore, this study observed the cured property to beam size. For this purpose, according to hatch spacing and beam size, the cure width and depth were measured on single cured line. Also, the cure width and depth were measured at single cured layer As a result of experiments. cure depth which varied from 0.23mm to 0.34mm was directly proportioned to beam radius. on the other hand, cure width which varied from 0.42mm to 1.07mm was inversely proportioned to beam radius. Surface roughness varied from 1.12 to 2.23 m for the ratio of hatch spacing to beam radius.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2010년도 정기 학술발표대회
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• pp.83.2-83.2
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• 2010

Stepped I-beams having increased moment of inertia at one end(singly stepped beam) or both ends(doubly stepped beams) can often be seen in construction of bridges due to material economy and easy fabrication of the section. This paper presents the results of the parametric study of lateral torsional buckling of monosymmetric stepped I-beams with constant depth subjected to equal and opposite end moments applied at the end of the beam. Design recommendations were made based on the finite element results of the models having different combinations of monosymmetric ratio, stepped length ratio, flange thickness ratio and flange width ratio,. The proposed approximation is acceptable based on the parameters given having mostly conservative results. The proposed equation can be further used to extend the study to different loading conditions.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권5호
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• pp.259-264
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• 2000

In this paper, the characteristics of piezoelectric transformer is studied for driving CCFL(Cold Cathode Fluorescent Lamp). In order to investigate the effects of geometrical dimensions, λvibration-mode type piezoelectric transformers with different sizes in the length(l), width$(\omega)$ and thickness(t) are made of ceramics with PZT-PMWS compositions. The increases in temperature and aging effect are also measured in the transformer of PT-3 sample under the condition of operation continuously for 10 hrs. As the results of dimensional effects, the output power and voltage step-up ratio are largely affected by the ratio of length to thickness(l/t) rather than that of length to $width(l/\omega)$. The output power and step-up ratio are increased with increasing l/t. On case of PT-3, the output voltages are 510[Vrms] at 36[Vrms] in input voltage, $100[k\Omega]$ in load resistance. Temperature increases and variation of output voltages are $10[^{\circ}C]$ and less than 5[%], respectively.

• 한국강구조학회 논문집
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• 제19권5호
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• pp.483-492
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• 2007

최근 대형 장스팬 규모에 많이 적용되는 PEB 시스템은 휨모멘트의 크기에 따라 부재형상을 최적화 한 변단면부재를 사용함으로써 경제적인 경쟁력을 갖는 구조시스템이다. 그러나 PEB 시스템의 관련기술은 대부분 외국에서 수입된 것으로 구조거동에 관한 연구 및 국내 설계규준이 미비하다. 특히 PEB 시스템에서의 변단면부재(래프터)들은 비조밀단면(noncompact section) 또는 세장단면(slender section)을 갖는 경우가 많으므로 좌굴에 대한 영향을 많이 받게 된다. 따라서 본 연구에서는 웨브의 판폭두께비, 스티프너 유무, 횡비지지길이 등을 변수로 하여 총 4개의 실대형 실험체를 제작 휨성능 실험을 수행하였다. 이에 대하여 세장한 웨브 변단면 부재의 구조 안정성을 실험적으로 평가하고 PEB 시스템의 설계를 위한 기초자료를 제공하고자 한다.

• 한국전기전자재료학회논문지
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• 제22권9호
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• pp.728-731
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• 2009

We report numerical simulations to investigate of the dependendce of the on/off current ratio and channel charge distributions in silicon nanowire (SiNW) field-effect transistors (FETs) on the channel width and thicknesses. In order to investigate the transport behavior in devices with different channel geometries, we have performed detailed two-dimensional simulations of SiNWFETs and control FETs with a fixed channel length L of $10\;{\mu}m$, but varying the channel width W from 5 nm to $5\;{\mu}m$, and thickness t from 10 nm to 30 nm. We have show that $Q_{ON}/Q_{OFF}$ drastically decreases (from $^{\sim}2.9{\times}10^4$ to $^{\sim}9.8{\times}10^3$) as the channel thickness increases (from 10 nm to 30 nm). As a result of the simulation using a quantum model, even higher charge density in the bottom of SiNW channel was observed then in the bottom of control channel.

• Imaging Science in Dentistry
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• 제48권3호
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• pp.191-199
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• 2018

Purpose: This study classified alveolar arch forms and evaluated differences in alveolar bone thickness among arch forms in the anterior esthetic region using cone-beam computed tomography (CBCT) images. Materials and Methods: Axial views of 113 CBCT images were assessed at the level of 3 mm below the cementoenamel junction (CEJ) of the right and left canines. The root center points of teeth in the anterior esthetic region were used as reference points. Arch forms were classified according to their transverse dimensions and the intercanine width-to-depth ratio. The buccolingual alveolar bone thickness of each tooth was measured at 3 mm below the CEJ and at the mid-root level. Differences in the mean thicknesses among arch forms were analyzed. Results: Anterior maxillary arches could be classified as long narrow, short medium, long medium, and long wide arches. Significant differences in buccolingual alveolar bone thickness among the arch groups were found at both levels. The long wide arches presented the greatest bone thickness, followed by the long medium arches, while the long narrow and short medium arches were the thinnest. Conclusion: Arch forms were classified as long narrow, short medium, long medium, and long wide. The buccolingual alveolar bone thickness exhibited significant differences among the arch forms.

• Advances in nano research
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• 제8권1호
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• pp.69-82
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• 2020

In this study, the free and forced vibration analysis of micro sandwich plate with porous core layer and magneto-electric face sheets based on modified couple stress theory and first order shear deformation theory under simply supported boundary conditions is illustrated. It is noted that the core layer is composed from balsa wood and also piezo magneto-electric facesheets are made of BiTiO₃-CoFe₂O₄. Using Hamilton's principle, the equations of motion for micro sandwich plate are obtained. Also, the Navier's method for simply support boundary condition is used to solve these equations. The effects of applied voltage, magnetic field, length to width ratio, thickness of porous to micro plate thickness ratio, type of porous, coefficient of porous on the frequency ratio are investigated. The numerical results indicate that with increasing of the porous coefficient, the non-dimensional frequency increases. Also, with an increase in the electric potential, the non-dimensional frequency decreases, while and with increasing of the magnetic potential is vice versa.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1695-1698
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• 2005

In this paper we investigate characteristics of deflection for circular plate with the non-symmetric boundary condition that is the boundary condition partly supported along the width direction of plate according to the length change of supporting end. For two boundary conditions such as simple supported and completely clamped boundary conditions, this study derives the maximum deflection formula of the circular plate using differential equation of elastic curve, assuming that a circular plate is a beam with the change of width and thickness along the longitudinal direction. The deflection formula of circular plate is verified by carrying out finite element analysis with regard to the ratio of length of supporting end to radius of circular plate.

• Design & Manufacturing
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• 제2권3호
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• pp.51-57
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• 2008

It is important factor to design the strip layout drawing according to product properties in press die design. Press dies are important processes in production such as a car component, house electronics, computer parts etc. In this paper, the strip layout of parts was designed for transfer dies. Results of this study can be modify the punch, trim position and notching shapes of strip layout. Utilization ratio was 70.3% by conducting piercing and notching for scrap design and materials were arranged with wide width of blank layout.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.316-316
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• 2022

Azuki bean is the important bean crop in Korea, and is traditionally used as a filling material for red bean porridge, rice cakes, and bread, as well as for sediment. So far, the National Insititute of Crop Science has developed azuki bean varieties for various uses, such as for sediment, tea, and azuki bean sprouts. Among azuki bean elite lines, 25 strains were used to analyze the correlation between red bean quality characteristics and sediment yield. The crude protein of red beans was 25.0-28.9%, ash content was 3.8-5.3%, and fat was 0.4-1.0%. As for the appearance quality characteristics of azuki bean, one hundred seed weight was 11.1-19.5 g, the length of seed was 6.45-8.49 mm, the width seed was 4.84-6.45 mm, and the withd/lenght ratio was 0.72-0.89. When the azuki bean were boiled, the thickness of the seed coat was 0.14-0.27 mm and the length ratio of seed was 0.65-0.76 mm, showing that the length of seed was slightly larger than the width. The yield of azuki bean sediment was 239-284% for whole red bean paste, and 144-203% for fine azuki bean paste. As a result of analyzing the correlation between the quality characteristics of azuki beans, such as protein, husk and seed weight, and the yield of azuki bean sediment, the yield of whole azuki bean sediment showed a negative correlation with the seed coat thickness and the length ratio of the original grain at -0.62 and -0.45, respectively. The yield of fine sediment showed a negative correlation with the length ratio of whole azuki beans at -0.49, and a positive correlation with that of white beans at 0.41. However, protein and ash content did not show any correlation with sediment yield. In view of the above results, it is thought that it would be better to have a high seed weight or a low width/length ratio of seed to develope azuki bean cultivar for sediment.