• 대한치과보철학회지
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• 제46권2호
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• pp.185-192
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• 2008

연구목적: 본 연구는 가변형 트레이 개발의 일환으로 그 시제품을 제작하고 비가역성 하이드로콜로이드 인상재를 사용하여 백인과 흑인에 서 인상채득시 트레이의 구강내 적합성를 알아보고자 하였다. 연구재료 및 방법: 가변형 트레이는 한국 성인 악궁의 크기 분석결과를 기본으로 하여 설계하였으며, CAD-CAM 작업을 통하여 견본 모형을 제작한 후 이를 이용하여 실리콘 간이 금형을 만든후 시제품을 제작하였다. 제작된 시제품을 이용하여 국내에 거주하는 백인 60명 (남자 30명, 여자 30명)과 흑인 60명 (남자 30명, 여자 30명)의 인상을 채득한 후 측정부위별로 인상체의 두께와 길이를 측정하여 그 적합도를 평가하였다. 결과: 1. 스탑과 경사면에 의해 트레이의 폭이 적절히 조절되어 균일한 인상체의 두께를 얻을 수 있었다. 2. 백인의 상악 트레이에서는 구개부 중앙이 13.0mm, 구개부 후방이 7.4mm로 비교적 인상체의 두께가 크게 측정되었다. 3. 백인의 하악 트레이에서는 전치 설측 기저부에서 인상체의 길이가 6.7mm로 길게 나타났으며 협측 제1,2 소구치 접촉점에서 폭이 6.7mm로 측정되었다. 설측 후방에서 폭이 2.9mm, 길이는 2.8mm로 조금 작게 측정되었다. 4. 흑인의 상악 트레이에서는 전치 순측 기저부에서 폭이 11.0mm, 구개부 중앙은 12.0mm, 구개부 후방은 11.0mm로 크게 측정되었으며 최후방 변연에서는 제2 대구치에서 후방 변연까지의 거리가 0.8mm로 작게 측정되었다. 5. 흑인의 하악 트레이에서는 전치 순측 기저부에서 폭이 9.2mm, 견치 순면에서 폭이 8.2mm로 비교적 크게 측정되었으며 최후방 변연에서는 제2 대구치에서 후방 변연까지의 거리가 0.3mm로 작게 측정되었다. 결 론: 이상과 같은 연구에 의해 측정된 값을 참고로 트레이의 변연 길이나 폭을 수정하고, 악궁의 해부학적 형태를 반영한다면, 이 가변형 트레이를 사용하여 백인과 흑인에서도 임상에서 보다 쉽고 정확한 인상채득을 할 수 있을 것이다.

• Design & Manufacturing
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• 제2권5호
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• pp.21-24
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• 2008

On this study, injection molding product of rectangular tray structure with thickness 0.25mm and aspect ratio(length/thickness) approximately 150 conducted. Technical aspects were reviewed on mold-die design and injection molding conditions. To have a thin-membraned plastic part, short-shot, shrinkage, twist, whitening and flash problems were considered and resolved. After measuring products, validity of this study and future improvement were discussed.

• 대한방사선치료학회지
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• 제8권1호
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• pp.41-54
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• 1996

The secondary electrons developed by interaction between primary beam and a tray mounted for blocks in Megavoltage irradiation result in excess soft radiation dose to the surface layer. To reduce this electron contamination, electron filters have been used to be attached under a tray. Various filters with Cu and Al plates in six different thickness and Cu/Al combined plates in 3 different thickness were tested to measure the reduction rate of secondary electron contamination to the surface layer. The measurement to find optimal filter was performed on 6MV linear accelerator in $10 cm{\times}10 cm$ field size and fixed 78.5cm source to measurement points distance from surface to maximum build up point in 2mm intervals. The result was analyzed as the ratio of measured doses with using filters, to standard doses of measured open beam. The result of this study was fellowing : 1. The contaminated low energy radiation were mainly produced by blocking tray. 2. The surface absorbed dose was slowly increased by increasing irradiation field size but rapidly increased at field size above $15cm{\times}15cm$. 3. Al plate upto 2.5mm thickness used as a filter was found to be inadequate due to the failure of reduction of the surface absorbed dose below doses of the under surface upto the maximal build up. Cu 0.5mm plate and Cu 0.28mm/A1 1.5mm compound plate were found to be optimal filters. 4. By using these 2 filters, the absorbed dose to the surface were effectively reduced $5.5\%$ in field size $4cm{\times}4cm,\;11.3\%$ in field size $10cm{\times}10cm,\;22.3\%$ in field size $25cm{\times}25cm$. 5. In field size $10cm{\times}10cm$, the absorbed dose to the surface of irradiation was reduced by setting TSD 20cm at least,. but effective and enough dose reduction could be achieved by setting TSD 30cm as 2 optimal filters used. 6. More surface dose absorbed at TSD less than 7.4cm with a tray and filters together indicated that soft radiation was also developed by filters. 7. The variation of PDD by the different size of irradiation field was minimal as 2 optimal filters used. There was also not different in variation of PDD according to using any of two different filters. 8. PDD was not effected either by various TSD or by using the different filter among two.

• 소음진동
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• 제11권3호
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• pp.471-476
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• 2001

This paper focuses on the numerical prediction of airflow-induced sound in DVD drives. As a first step, computational fluid dynamics (CFD) is conducted to evaluate flow field characteristics due to the high-speed disk rotation, and to support the acoustic analysis. Acoustic analogy based on Ffowcs Wi1liams-Hawkings (FW-H) equation is adopted to predict aeroacoustic noise patterns. The integral solution for quadrupole volume source is included to identify the turbulence noise generated inside the DVD tray. The strength of sound pressure revel with respect to rotating speed is discussed to meet upfront demand on the high fidelity product development. The present study also focuses on the noise directivity and examines how much the sound noise is sensitive to change in rotating speed. Near-field noise is strongly affected by the flow field characteristic, which is caused by the complex shape of the tray. For a mid-field, the quadrupole noise play as a counterpart of thickness noise or loading noise, so it generates different sound noise Patterns compared with those in the near field.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.502-507
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• 2000

This paper presents the numerical prediction of airflow-induced sound in DVD drives. Computational fluid dynamics (CFD) is first conducted to evaluate flow field characteristics due to the high-speed disk rotation, and to support the acoustic analysis. The acoustic analogy based on Ffowcs Williams-Hawkings (FW-H) equation is adopted to predict aeroacoustic noise patterns. The integral solution for quadrupole volume source is included to identify the turbulence noise generated inside the DVD tray. Near-field noise is strongly affected by the flow field characteristic, which is caused by the complex shape of the tray. For a mid-field, the quadrupole noise play as a counterpart of thickness noise or loading noise, resulting in a different pattern compared with those in the near field.

• 방사선산업학회지
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• 제7권2_3호
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• pp.115-119
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• 2013

The density profile measurement technology by gamma transmission has been widely used to diagnose processes in the field of refinery and petrochemical industry. This technology can reveal a clue and position of abnormal phenomenon of industrial processes during their operation. In this paper, the feasibility of the gamma transmission technology for detecting changes in the amount of fluid in a distillation column was evaluated by using Monte Carlo simulations. The simulations assumed that $^{60}Co$ (1.17, 1.33 MeV) sources and NaI (Tl) detectors (${\Phi}5{\times}5cm$) are located in opposite sides of a column and it concurrently moves in vertical direction. To determine the dependency of a spatial resolution on aperture size of a collimator, the simulation model for a tray in a column were simulated with the aperture sizes of 1 and 2 cm. The thickness of the high density area including a tray and fluid was 7.6 cm in the simulation. The spatial resolution of the tray was 8.2 and 8.5 cm, respectively. As a result, it was revealed that the conventional density profile measurement technique is not able to show the deviation of liquid level on a tray in a column.

• 한국가금학회지
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• 제21권1호
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• pp.1-19
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• 1994

난좌(卵座)의 구면(球面)과 난각(卵殼)의 구면(球面)이 계란(鷄卵)의 파각도(破殼度)에 미치는 영향(影響)을 구명(究明)코져 실험(實驗)을 실시(實施)하였던바 다음과 같은 결과(結果)를 얻었기에 보고(報告)하는 바이다. 1. 9개 국가(國家)(미국, 프랑스, 이태리, 태국, 일본, 네델란드, 러시아, 한국, 스위스)에서 수집(蒐集)한 22종의 난좌형태(卵座形態)를 조사(調査)한 결과(結果), 우리 나라의 난좌(卵座)를 제외(除外)한 8개 국가(國家)의 난좌(卵座)는 그 세부(細部) 형태(形態)가 모두 상이(相異)하였다. 2. 4개의 모형난좌(模型卵座)에서 파각도(破殼度)를 측정(測定)한 결과(結果) B형, D형이 가장 파격도(破格度)가 높은 결과(結果)였다. 앞으로 난좌(卵座)를 제조(製造)할시 계란(鷄卵)의 구면(球面)과 난좌(卵座)의 구면(球面)이 서로 알맞아 파각도(破殼度)를 높일 수 있는 본(本) 시험(試驗)의 B형과 D형으로 제조(製造)하는 것이 가장 바람직할 것으로 사료되었다. 난좌가 견고하다고 해서 파각도가 높아지는 것은 아니었다. 본(本) 실험(實驗)에 공시(供試)한 전체(全體) 계란(鷄卵)의 난각(卵殼) 두께 성적의 통계 처리 결과 유의성이 없었다(P>0.05). 3. 난좌(卵座)에 포장(包裝)되어 계란(鷄卵)이 수송(輸送)될 때, 그 계란(鷄卵)의 구면(球面)에 따라 난좌(卵座)의 형(型)이 얼마나 넓은 면적(面積)으로 감쌀 수 있느냐가 파각도(破殼度)를 좌우(左右)하는 중요(重要)한 관건(關鍵)임을 알 수 있었다. 따라서 난좌(卵座) 제조시(製造時) 상단부(上段部) 난중(卵重)이 하단부(下段部) 난좌(卵座) 내부(內部)의 계란(鷄卵)에 미치는 하중(荷重)을 고려해서 난좌(卵座)의 내부구면(內部球面)과 계란(鷄卵)의 외내부구면(外內部球面)이 알맞을 수 있도록 만들어야 할 것으로 사료(思料)되었다. 4. 현재(現在) 우리나라에서 실시(實施)하고 있는 것처럼 1개의 난좌형(卵座型)으로 대란(大卵), 중란(中卵) 및 소란(小卵)을 공통(共通)으로 사용(使用)하는 것보다는 난중(卵重)에 따른 적정(適正) 난좌(卵座)가 개발(開發)되어 사용(使用) 될 수 있는 방안(方案)도 강구(講究)되어야 할 것으로 사료(思料)되었다.

• 한국연초학회지
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• 제19권2호
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• pp.102-106
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• 1997

The inluence of styrofoam-panel thickness of floating frame on the seedling growth of flue-cured tobacco(Nicotiana tabacum L.) in the newly developed direct-seed float system was investigated . Floating frame used instead of styrofoam-tray consisted of styrofoam-panel (106×108cm) for floating, eight holes(1.Sx2S.0 cm) to uniform the water, and nutrition supply far seedling and water and nutrition absorption cloth placed on the styrofoam-panel. Each floating-frame may lay eight plastic-trays on it. Eight grades of styrofoam-panel thickness from 26 mm to 46mm and two kinds of media were used in the greenhouse system. Dry cells were found from the styrofoam-panel thickness of 43mm in carbonized chaff, compost and original soil rate of L3-3(v/v) media, and of 37mm in peat and perlite rate of 8-2(v/v) media. The thinner styrofoam-panel produced more tender and succulent seedling with the more trunk and the less root weight. When considering the appearance of dry cell, seedling growth, producing healthy tobacco seedlings, and utilization of styrofoam-panel for two kinds of medias the ideal styrofoam-panel thickness were suggested to be around 34mm for flue-cured tobacco reeling production in the newly developed direct-seeding float system. Key words : tobacco seedlings, float system, medium, styrofoam pannel, dry cell.

• 한국포장학회지
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• 제11권1호
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• pp.17-24
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• 2005

During handling unitized products, they are subjected to a variety environmental hazards. Shock and vibration hazards are generally considered the most damaging of the environmental hazards on a product, and it may encounter while passing through the distribution environment. A major cause of shock damage to products is drops during manual handling. The increasing use of unitization on pallets has been resulted in a reduction in the manual handling of products and with it a reduction in the shock hazards. This has caused and increasing interest in research focused on vibration caused damage. the use of pallets as a base for unitizing loads, aids in the mechanical handling, transportation and storage of products. Besides aiding in the handling, transportation and storage of products, a pallet also acts on and interface between the packaged goods and the distribution environment. The determination of the impact deformation of the cushioning materials such as tray cup (polymeric foam) and corrugated fiberboard pad must be carried out to design the proper packaging system providing adequate protection for the fruit, and to understand the complex interaction between the components of fruit when they relate to expected transportation vibration inputs. In this study, the theoretical analysis of impact deformation for cushioning materials by dynamic vibration. The impact deformations of SW and DW corrugated fiberboard pad in acceleration amplitudes of 0.25 G-rms and 0.5 G-rms that were usually generated in transport vehicles during distribution environments were very small compare with the thickness of corrugated fiberboard pad. The maximum of vibration acceleration level of tray cup by vibration impact was about 3.2 G-rms. The theoretical allowable acceleration (G-factor) of the pear was 0.7102 G-rms, and the maximum dynamic deformation estimated within G-factor was about 1 mm.

• 한국환경과학회지
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• 제30권8호
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• pp.685-691
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• 2021

This study aimed to find a suitable size and a seedling raising stage for growing cuttings of Euonymus fortunei 'Emerald and Gold' using plug trays. The experimental method, involved cutting two nodes from a solitary branch of E. fortunei 'Emerald and Gold', and the use of 32 (143 mL/cell), 50 (70 mL/cell), 105 (18 mL/cell), 200 (13 mL/cell) plug trays. The cuttings were transplanted to trays after they were filled with a universal horticultural medium. To compare the growths, plant heights, the numbers of leaves, longest root lengths, thickness/radius ratios, dry weights, and fresh weights were measured from July to October, and statistical analyses were performed using both the two-way repeated-measures analysis of variance (ANOVA) and Tukey's post-test. The results confirmed that the size of the plug tray and the seedling raising stage had a significant effect on the growth of E. fortunei 'Emerald and Gold.' In addition, the overall growth was high and the change in growth was relatively rapid in districts 50 and 105. Therefore, it can be considered appropriate to use 50 and 105 trays when growing cuttings of E. fortunei 'Emerald and Gold' on plug trays.