• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.786-792
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• 2010

본 논문에서는 스윕과 린의 각도에 따른 부분흡입형 초음속 터빈의 성능 특성을 분석하기 위하여 유동해석을 실시하였다. 유동해석은 스윕과 린의 3가지 각도($5^{\circ}$, $10^{\circ}$, $15^{\circ}$)에 대해 수행되었다. 해석결과, 전반적으로 스윕 각도에 커질수록 효율이 증가하였다. 다만, 스윕 각도가 $5^{\circ}$일 때에는 기본익형보다 효율이 더 떨어졌다. 린 각도가 커질수록 전압력 손실은 줄어들었지만 정효율은 감소하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제12권1호
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• pp.53-61
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• 1988

Most of the recent for the flow field hydrofoil in partially cavitating condition are the ones which are linearized, and the problem of cavity end region for hydrofoil is not verified. This paper deals with a study on characteristics of end region flow field for partially cavitating hydrofoil by using a characteristics of shear turbulence flow and nonlinear cavity flow theory. The results obtained as follows : 1) Shear layer thickness is decreased gradually going to the end section of hydrofoil. When attack angle is large, it is appeared largely at the region of partial cavitation after its collapsing. 2) The fluctuation velocity of a second-degree relative direction have minimum value at the front of hydrofoil or at the end of hydrofoil. The difference for the validity of attack angle is appeared largely at the surrounding of .chi.$_{e}$ point. 3) The fluctuation velocity of transverse direction decrease from the maximum thickness of cavitation to the end of hydrofoil, but it undergoes largely the effect of pressure recovery. The difference is larger at the region of partial cavitation after its collapsing than at the of hydrofoil. 4) The distribution of Reynolds stress have maximum values at the region of partial cavitation after its collapsing and the end of foil, and the larger attack angle, the larger the distribution of value.e.

• 디지털산업정보학회논문지
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• 제14권4호
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• pp.9-16
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• 2018

This study described partial discharge(PD) distribution analysis between the XLPE(Cross-Linked PolyEthylene)and EPDM(Ethylene Propylene Diene Monomer) interface with unsupervised classification. The ${\phi}-q-n$ patterns were analyzed using phase resolved partial discharge(PRPD). K-means cluster analysis forms a cluster based on similarities and distances among scattered individuals, and analyzes the characteristics of the formed clusters, dividing the multivariate data into several groups according to the similarity of each characteristic, Is a statistical analysis that makes it easier to navigate. It was confirmed that the phase angle of the cluster with the maximum discharge charge was concentrated around $0^{\circ}$ and $180^{\circ}$ at 30 kV after the initial phase distribution localized around $90^{\circ}$ and $300^{\circ}$ expanded to the whole phase angle according to the voltage rise. The Euclidean distance between the center of gravity and the discharge charge in the ${\Phi}-q$ cluster increased with increasing applied voltage.

• 대한치과의사협회지
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• 제55권8호
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• pp.528-536
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• 2017

Treatment with removable partial denture is effective for partially edentulous patients who are unable to obtain sufficient retention and stability for functional and esthetic restoration. There are several cases reporting the improvement of retention and stability of the partial denture using a small number of implants. However, there are limited studies on the implant-assisted removable partial denture using a small number of remaining teeth and the bar locator system. The bar locator system has an advantage in that it could compensate the angle of insertion of removable prosthesis on implant with inconsistent placement angle due to anatomical constraints compared to when using the locator only. This case report describes the patient with $Parkinson^{\circ}$Øs disease who was treated with the Locator bar system using two previously placed implants and two remaining teeth on maxilla. No additional implants could be placed because of the medical and economic condition of the patients, and the angle of one of two implants could not be matched with the direction of the removable partial denture insertion. Considering the angle of the implants, the patient was treated with implant-assisted RPD using the Locator bar system and had satisfactory results in the aspect of esthetics, masticatory function, and oral hygiene maintenance.

• The Journal of Advanced Prosthodontics
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• 제14권3호
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• pp.150-161
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• 2022

PURPOSE. The purpose of the study was to assess the influence of build orientations and density of support structures on the trueness of the 3D printed removable partial denture (RPD) frameworks. MATERIALS AND METHODS. A maxillary Kennedy class III and mandibular class I casts were 3D scanned and used to design and produce two 3D virtual models of RPD frameworks. Using digital light processing (DLP) 3D printing, 47 RPD frameworks were fabricated at 3 different build orientations (100, 135 and 150-degree angles) and 2 support structure densities. All frameworks were scanned and 3D compared to the original virtual RPD models by metrology software to check 3D deviations quantitatively and qualitatively. The accuracy data were statistically analyzed using one-way ANOVA for build orientation comparison and independent sample t-test for structure density comparison at (α = .05). Points study analysis targeting RPD components and representative color maps were also studied. RESULTS. The build orientation of 135-degree angle of the maxillary frameworks showed the lowest deviation at the clasp arms of tooth 26 of the 135-degree angle group. The mandibular frameworks with 150-degree angle build orientation showed the least deviation at the rest on tooth 44 and the arm of the I-bar clasp of tooth 45. No significant difference was seen between different support structure densities. CONCLUSION. Build orientation had an influence on the accuracy of the frameworks, especially at a 135-degree angle of maxillary design and 150-degree of mandibular design. The difference in the support's density structure revealed no considerable effect on the accuracy.

• 한국전기전자재료학회논문지
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• 제20권9호
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• pp.780-786
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• 2007

This paper describes the influence on partial discharge characteristics of defects at the model XLPE/EPDM interfaces of power cable joints. The defects of void and copper which could inadvertently be present at the joint interface. We measured ${\Phi}-n,\;{\Phi}-q$ patterns by a computer-aided partial discharge measuring system. Several parameters i, e, maximum discharge $q_{max}$ [pC], average discharge q [pC/cycle], and average angle of discharge ${\Theta}g$ [deg] were found to depend upon the defect type varying applied voltage. As the result of time evaluation, partial discharges are small different at copper defects, but is decreasing obviously about 20 minutes at void defect. It considered that difference of magnitude of total positive discharge of Q+ [pC] and total negative discharge of Q- [pC] is SPMD(swarming pulsive micro discharges).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
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• pp.43-46
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• 2004

Recently many research activities on the diagnosis of stator winding insulation of high-voltage motors have been reported. Most of them utilize a trend analysis of partial discharges. In this paper, a novel on-line monitoring system for an insulation diagnosis is proposed. This system displays magnitude and phase angle distribution of partial discharge. The partial discharge activities can be interpreted more precisely by these techniques.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.584-587
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• 1993

Mica, which have a good thermal and electrical characteristics, while will cleave easily at these layers. In order to bond mica materials soldily, mica/epoxy composite insulation materials were developed for generator stator winding. There are lots of problems such as delamination and partial discharge of these insulation materials caused by mechanical, electrical and thermal aging. Several experiments have been conducted in order to find the useful diagnostic parameters from the partial discharge phenomena by applying a new measurement techniques. this paper deals with the partial discharge pulse characteristics, which may be a useful diagnostic concept in predicting insulation condition of generator stator insulation materials. Long term insulation aging test shows that partial discharge phase angle an magnitude are identified as one of the main key techniques for insulation diagnosis on generator stator winding.

• 한국추진공학회지
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• 제11권4호
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• pp.10-18
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• 2007

본 연구에 채택된 마이크로터빈은 축류형 터빈으로 2단으로 구성되어져 있으며 로터 유로에서의 평균반경이 8.4 mm이다. 이러한 소형 터빈은 마이크로 동력시스템의 드라이브로 사용되어질 수 있으며 무부하 상태에서 100,000 RPM의 회전속도에 도달한다. 하지만 낮은 부분분사에서 작동하므로 동익과 정익의 익형각에 따라 성능의 변화가 발생되어진다. 따라서 노즐, 정익, 동익의 익형각을 변경하면서 비출력과 총 비토오크를 측정하여 각각의 성능을 분석하였다. 성능실험의 결과에 의하면 동익 익형각의 변화에 따라 총 비토오크가 15%까지 변경되어졌으며 최적의 입사각은 $10.3^{\circ}$ 정도였다.

• 한국전기전자재료학회논문지
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• 제11권12호
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• pp.1055-1059
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• 1998

The correlation between the propagation of electrical tree and distributions of partial discharge(PD) pulses accompanying with electrical tree of bush type in low density polyethylene were discussed. We measured the growth of electrical tree by using optical microscope and PD data simultaneously. The PD data detected and analyzed were PD magnitude, repetition rate, average discharge power, average phase angle, and $\psi$-q-n distribution pattern. The average discharge power and repetition rate of PD had good linear relation with area of tree. Repetition rate and peak discharge magnitude and width of discharge phase angle increased with the tree.