• 대한기관식도과학회:학술대회논문집
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• 대한기관식도과학회 1976년도 제10차 학술대회연제 순서 및 초록
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• pp.86.2-86
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• 1976

저자들은 1975~1976.3까지 만 1년 3개월간 자각난청을 주소로 내원한 환자에게 실시한 순음청력검사중 고막 천공이 없는 165례(남 101, 녀 64), 총 223이에 대하여 청력상에 따른 연령별, 성별, 측별, 발생기간별, 원인별, 고막소견 및 청력소실의 정도 등에 관하여 임상통계적 고찰을 하여 다음과 같은 결론을 얻었다. 1. 청력상은 정상(30례, 18.18%), 수평형(46례, 27.88%), 점경형(34례, 20.6%), 상승형(5례, 3%), 산형(9례, 5.45%), 곡형(7례, 4.24%), 전롱(24례, 14.55%), 기타(10례, 6%)로 구분하였다. 2. 연령은 20대군이 50례(30.3%)로 가장 많았고 그 다음이 10대(43례, 26%), 30대(27례, 16. 36%)의 순이었다. 3. 성별비는 남여비가 101명 : 64명으로 1.6 : 1이었다. 4. 측별빈도는 58례에서 양측성이었고 77례에서 일측성이었다. 5. 발생기간은 3개월 미만이 45례(27.3%)로 가장 많았고 10년 이상이 28례(16.9%), 6~10년 까지가 21례(12.7%)의 순이였으며 특히 전농에서는 10년 이상이 거의 대부분이였다. 6. 원인별로는 원인불명이 99례(60%)로 가장 많았고 두부외상이 31례(18.8%), 그 다음이 중이성 12례(7.3%)였으며 그 외 노인성, 응향성 등은 극소수였다. 7. 고막소견은 정상소견을 나타낸 것이 177이(79.4%)로 가장 많았고 고막내함이 28이(12.6%).......등이었다. 8. 청력정균소실 정도는 청력상과 관계없이 경도의 난청에서 고도의 난청에 이르기까지 균등하게 분포되어 있었다.

• Structural Engineering and Mechanics
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• 제36권3호
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• pp.247-278
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• 2010

The study of the seismic vulnerability of masonry buildings requires structural properties of walls such as stiffness, ultimate load capacity, etc. In this article, a method is suggested for modeling the masonry walls under in-plane loading. At the outset, a set of analytical equations was established for determining the elastic properties of an equivalent homogeneous material of masonry. The results for homogenized unreinforced brick walls through detailed modeling were compared in different manners such as solid and perforated walls, in-plane and out-of-plane loading, etc, and it was found that this method provides suitable accuracy in estimation of the wall linear properties. Furthermore, comparison of the results of proposed modeling with experimental out coming indicated that this model considers the non linear properties of the wall such as failure pattern, performance curve and ultimate strength, and would be appropriate to establish a parametric study on those prone factors. The proposed model is complicated; therefore, efforts need to be made in order to overcome the convergency problems which will be included in this study. The nonlinear model is basically semi-macro but through a series of actions, it can be simplified to a macro model.

• Steel and Composite Structures
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• 제49권4호
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• pp.361-380
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• 2023

A size dependent bending behavior of piezoelectrical flexoelectric layered perforated functionally graded (FG) composite nanobeam rested on an elastic foundation is investigated analytically. The composite beam is composed of regularly cutout FG core and two piezoelectric face sheets. The material characteristics is graded through the core thickness by power law function. Regular squared cutout perforation pattern is considered and closed forms of the equivalent stiffness parameters are derived. The modified nonlocal strain gradient elasticity theory is employed to incorporate the microstructure as well as nonlocality effects into governing equations. The Winkler as well as the Pasternak elastic foundation models are employed to simulate the substrate medium. The Hamiltonian approach is adopted to derive the governing equilibrium equation including piezoelectric and flexoelectric effects. Analytical solution methodology is developed to derive closed forms for the size dependent electromechanical as well as mechanical bending profiles. The model is verified by comparing the obtained results with the available corresponding results in the literature. To demonstrate the applicability of the developed procedure, parametric studies are performed to explore influences of gradation index, elastic medium parameters, flexoelectric and piezoelectric parameters, geometrical and peroration parameters, and material parameters on the size dependent bending behavior of piezoelectrically layered PFG nanobeams. Results obtained revealed the significant effects both the flexoelectric and piezoelectric parameters on the bending behavior of the piezoelectric composite nanobeams. These parameters could be controlled to improve the size dependent electromechanical as well as mechanical behaviors. The obtained results and the developed procedure are helpful for design and manufacturing of MEMS and NEMS.

• 패션비즈니스
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• 제2권4호
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• pp.93-101
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• 1998

Knit products which had been limited only to underwear, recently became popularized, fashionized and highly classified covering even outer garments such as sportswear like golfwear, woman's dress, and man' s suit. As fashion cycle is getting shorter and the more a nation advanced prefers knit to woven fabrics knit industry has a very bright prospect, particularly woman's knit which is sensitive to fashion can be said as a fashion product with high value added. This study is to grasp the physical properties of stitch which are fundamental to the development of knit products. For this purpose, 2/20s of 100% wool were woven by the author of this study to basic plain stitch, rib stitch, varied transfer stitch, and float stitch on a SEMASEIKI cross knitter 7G to test the physical properties, and the result was as follows; 1. As for the relation between knit stitch and rate of extension recovery, rate of extension recovery was higher in the course direction than in the wale direction of three stitches except transfer stitch; rib stitch showed the highest rate of extension recovery in the course direction while float stitch showed the highest rate of extension recovery in the wale direction. 2. As for the relation between knit stitch and bursting strength elastic rib stitch showed higher bursting strength to indicate elasticity is an important factor of bursting strength and float stitch showed higher bursting strength too to indicate that the floating yarn on the surface plays a role of support. 3. As for the relation between knit stitch and air permeability perforated transfer stitch showed the lowest air permeability to prove that the size of perforation affects on the air permeability a great deal. 4. As for the relation between knit stitch and warmth retaining rib stitch through two lined needle bar showed the highest degree. The reason the warmth of perforated transfer stitch didn't decrease much was because the perforation wasn't big enough and content of air increased from the unevenness of the perforated parts through stitch variation. Based upon this result, each stitch can be characteristically summarized as follows; plain stitch showed a stable condition of knit cloth in four kinds of physical property test. And rib stitch is proper to tighten the edge of sleeve or clothe making use of its excellent extension recovery and to make socks for the highest bursting strength and warmth retaining. In the case of transfer stitch, seasonable designs can be taken by controlling the size of loop. Considering the pleasantness, underwear should be made of stitches with good air permeability float stitch was revealed to have color and pattern effects and a great bursting strength. This study has limitations in the aspect that it dealed with a small part of various knit stitches and the items of physical property test were not enough. The author of this study hopes that further studies would make deeper understandings about knit stitch based on more varied stitches and physical property tests ultimately to contribute to the development of fashionable designs proper to maximize the usage, function and originality.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.435-437
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• 2002

Polishing of copper, a process called copper chemical mechanical polishing, is a critical, intermediate step in the planarization of silicon wafers. During polishing, the electrodeposited copper films are removed by slurries: and the differential polishing rates between copper and the surrounding silicon dioxide leads to a greater removal of the copper. The differential polishing develops dimples and furrows; and the process is called dishing and erosion. In this work, we present the results of experiments on dishing and erosion of copper-CMP, using patterned silicon wafers. Results are analyzed for the pattern factors and properties of the copper layers. Three types of pads - plain, perforated, and grooved - were used for polishing. The effect of slurry chemistries and pad soaking is also reported.

• 치과방사선
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• 제17권1호
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• pp.233-248
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• 1987

The author studied the effect of periapical bone loss on radiographic interpretation by using a dry adult human mandible. Artificial bony lesions were created at the apices of two mandibular second molars and four mandibular bicuspids. The jaw was stabilized and various artificial lesions were radiographed under ideal circumstances. Radiographic pictures were recorded and compared with the size of the actual lesions. The obtained results were as follows: 1. The size of actual lesions were always larger than their radiographic pictures. 2. The size of actual lesion had a greater discrepancy in the molar area where the cortical plates were havier, but the lesions in the bicuspid areas were only slightely larger than their radiographic pictures, and in these areas the cortical plates were quite thin. 3 Periapical lesions located in cancellous bone did not appear on a radiograph, regardless of the size of the created lesion, but when the junctional bone was involved or the cortical plate was perforated, the definite bone destructive change was observed on the roentenogram. 4. Removal of the entire buccal or lingual plate did not affect the trabecular pattern of bone on the roentgenogram. 5. When the cancellous bone and junctional bone were removed simultaneously, altered trabecular patterns were observed on the roentgenogram.

• 대한기계학회논문집B
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• 제35권8호
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• pp.855-860
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• 2011

용존공기부상조의 파일럿실험장치 설계를 위한 사전 검증 작업으로서 부상조의 유동을 이차원 이상유동으로 가정하여 수치적으로 모사하였다. 형상이 변경된 다양한 부상조와 기준부상조와의 간접적인 성능 비교를 위하여 분리조에서의 하강속도를 비교하였다. 해석 결과 기준부상조의 분리조에서는 잘 설계된 High-rate DAF 의 전형적인 유동 패턴이 관찰되었다. 이러한 유동패턴은 Baffle 각도나 접촉조의 폭과 같은 다른 형상 변수와 상관없이 Baffle 이 충분히 높을 때 잘 유지되었다. 그러나 Baffle 높이 및 각도, 접촉조의 폭 및 다공판의 설치유무는 분리조에서 하강속도의 균일성에 영향을 미쳤다. 기준부상조에서 Baffle의 높이를 제외한 다른 형상을 변화시키지 않았을 때, 분리조에서의 하강속도가 균일한 것으로 나타났다. 이것은 기준부상조의 형상최적화가 잘 되어있음을 의미한다.

• 한국유체기계학회 논문집
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• 제8권4호
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• pp.39-47
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• 2005

The present study has been performed to investigate the influences of rectangular fins on heat transfer in an impingement/effusion cooling system with crossflow. To simulate the impingement/effusion cooling system with initial crossflow, two perforated plates are placed in parallel and staggered arrangements with a gap distance of 2 times of the hole diameter. The crossflow passes between the plates, and various rectangular fins are installed on the plates. Reynolds number based on the hole diameter is fixed to 10,000 and the flow rate of crossflow is changed from 0.5 to 1.5 times of that of the impinging jet. A naphthalene sublimation method is used to obtain the heat/mass transfer coefficients on the effusion plate. Also to analyze the flow characteristics, a numerical calculation is performed. When rectangular fins are installed, the flow and heat transfer pattern is changed greatly from the case without fins. In the injection hole region, the jet impinges on effusion plate without deflection and wall jet spreads symmetrically. In the effusion region, the crossflow accelerates due to the decrease of cross-sectional area in the channel. Local heat/mass transfer coefficients are enhanced significantly compared to the case without fins. As the blowing ratio increases, the effect of rectangular fins against the crossflow becomes more significant and then the higher average heat/mass transfer coefficients are obtained than the case without fins. However, the increase of blockage effect gives more pressure loss in the channel.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.289-296
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• 2004

The present study has been performed to investigate the influences of rectangular fins on heat transfer in an impingement/effusion cooling system with crossflow. To simulate the impingement/effusion cooling system with initial crossflow, two perforated plates are placed in parallel and staggered arrangements with a gap distance of 2 times of the hole diameter. The crossflow passes between the plates, and various rectangular fins are installed on the plates. Reynolds number based on the hole diameter is fixed to 10,000 and the flow rate of crossflow is changed from 0.5 to 1.5 times of that of the impinging jet. A naphthalene sublimation method is used to obtain the heat/mass transfer coefficients on the effusion plate. Also to analyze the flow characteristics, a numerical calculation is performed. When rectangular fins are installed, the flow and heat transfer pattern is changed greatly from case without fins. In the injection hole region, the jet impinges on effusion plate without deflection and wall jet spreads symmetrically. In the effusion region, the crossflow accelerates due to the decrease of cross-sectional area in the channel. Local heat/mass transfer coefficients are enhanced significantly compared to case without fins. As the blowing ratio increases, the effect of fins against the crossflow becomes more significant and then the higher average heat/mass transfer coefficients are obtained than the case without fins.

• 한국식품저장유통학회지
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• 제9권2호
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• pp.121-125
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• 2002

방울토마토의 포장에 적합한 필름을 선택하기 위하여 기체 투과도가 다른 여러 가지 필름으로 방울토마토를 포장하고 저장하면서 포장내 기체 농도, 총균수, 효모 및 곰팡이 수, 중량 감소율, 부패율 등을 조사한 결과는 다음과 같았다. CPP와 PD961로 포장한 시험 구는 저장 기간 동안 계속 적으로 산소와 이산화탄소 농도가 계속적으로 변화하였으나 다른 포장재로 포장한 시험구는 저장 10일 경에 대체적으로 평형에 도달하였다. 저장 기간 중 중량 감소율은 PY85로 포장한 시험구가 가장 현저하였으며 다른 포장재로 포장한 시험구는 저장 20일까지도 1% 부근이었다. 포장 직후의 총 균 수는 $10^4$ CFU/g 부근이었으며, 이들은 대부분 곰팡이나 효모인 것으로 나타났다. 또한 저장 기간이 경과함에 따라서 대체적으로 미생물의 수는 증가하였다. CPP로 포장한 시험구는 저장 5일에는 총균수, 효모 및 곰팡이 수가 가장 적었으나 10일 이후에는 가장 많았으며, 저장 20일에는 총균수가 $10^{8}$ CFU/g이었으며, 효모 및 곰팡이 수는 $10^{7.97}$ CFU/g 이었다. 저장 기간 중 pH는 대체적으로 증가하였으며, 총산 및 가용성 고형물은 큰 변화가 없으나 대체적으로 감소하였다. 단지 PY85로 포장한 시험구는 저장 기간동안 지속적으로 총산과 가용성 고형물이 증가하였다. 저장 5일 이후에는MPD와 PY85를 제외한 시험구에서 부패가 발생하기 시작하였으며, CPP와 PD961로 포장한 시험구의 부패율이 대체적으로 높았다. MPD는 저장 20일에도 5.3%의 가장 낮은 부패율을 보였다.다.