• 제목/요약/키워드: Defect Density

검색결과 460건 처리시간 0.028초

다단계 임계화와 확률 밀도 함수를 이용한 TFT-LCD 결함 검출 (TFT-LCD Defect Detection Using Multi-level Threshold and Probability Density Function)

  • 김세윤;정창도;윤병주;주영복;최병재;박길흠
    • 한국지능시스템학회논문지
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    • 제19권5호
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    • pp.615-621
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    • 2009
  • TFT-LCD 영상은 불균일한 휘도 분포와 노이즈 신호, 그리고 결함 신호로 구성되어 있다. 결함 신호는 주변 정상 영역의 화소값 분포에 비해 일정한 변화를 가지는 영역으로서 육안 검출이 어려운 수준의 한도성 결함을 포함한다. 본 논문에서는 다단계 임계화를 통해 신뢰할 수 있는 수준까지 결함과 결함 유사 영역을 모두 검출하는 과검출(過檢出)을 수행하고, Parzen Window를 이용한 확률 밀도 함수를 통해 실제 결함이 아닌 유사 영역을 제거하는 알고리즘을 제안하였다. 제안한 알고리즘의 유효성을 확인하기 위해 다양한 실험 영상에 대한 실험 결과를 살펴보고 실제 TFT-LCD 영상에 적용하여 봄으로써 신뢰성 있는 결함 검출에 적합함을 입증하였다.

임프란트 식립시 이식된 탈회골기질을 함유한 이식재의 골형성에 대한 연구 (A STUDY ON THE BONE FORMATION OF GRAFT MATERIAL CONTAINING DEMINERALIZED BONE MATRIX WITH A SIMULTANEOUS INSTALLATION OF IMPLANT)

  • 김여갑;윤병욱;류동목;이백수;오정환;권용대
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • 제31권6호
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    • pp.481-491
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    • 2005
  • Purpose: The aim of the present study is to evaluate the effect of autogenous bone and allograft material coverd with a bioresorbable membrane on bone regeneration after a simultaneous installation of implant. Materials and methods: Twelve healthy rabbits, weighing about $3{\sim}4$ kg, were used in this experiment. Following impalnt(with 3.25 mm diameter and 8 mm length) site preparation by surgical protocol of $Oraltronics^{(R)}$, artificial bony defect, 5mm sized in height and depth, was created on femoral condyle using trephine drill(with 5 mm diameter and 5 mm length). Then implant was inserted. In the experimental group A, the bony defect was filled with autogenous particulated bone and coverd with $Lyoplant^{(R)}$ resorbable membrane. In the experimental group B, the bony defect was filled with allograft material(Orthoblast $II^{(R)}$) containing demineralized bone matrix and covered with $Lyoplant^{(R)}$. In the control group, without any graft materials, the bony defect was covered with $Lyoplant^{(R)}$. The experimental group A and B were divided into each 9 cases and control group into 3 cases. The experimental animals were sacrificed at 3, 6 and 8 weeks after surgery and block specimens were obtained. With histologic and histomorphometric analysis, we observed the histologic changes of the cells and bone formation after H-E staining and then, measured BIC and bone density with KAPPA Image $Base^{(R)}$ system. Results: As a result of this experiment, bone formation and active remodeling process were examined in all experimental groups and the control. But, the ability of bone formation of the experimental group A was somewhat better than any other groups. Especially bone to-implant contact fraction ranged from 12.7% to 43.45% in the autogenous bone group and from 9.02% to 29.83% in DBM group, at 3 and 8 weeks. But, bone density ranged from 15.67% to 23.17% in the autogenous bone group and from 25.95% to 46.06% in DBM group at 3 and 6 weeks, respectively. Although the bone density of DBM group was better than that of autogenous bone group at 3 and 6weeks, the latter was better than the former at 8 weeks, 54.3% and 45.1%, respectively. Therefore these results showed that DBM enhanced the density of newly formed bone at least initially.

후육 Al 주조재의 기포결함 최소화를 위한 임계냉각속도의 영향 (Effect of Critical Cooling Rate for Minimization of Porosity in the Thick Aluminum Casting)

  • 곽시영;조인성;김용현;이희권
    • 한국주조공학회지
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    • 제37권6호
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    • pp.181-185
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    • 2017
  • In the present study, the effect of cooling rate on the formation of the porosity in the thick aluminum sand casting was investigated. Nowadays, due to considerations of weight and cost reduction, large scale thick aluminum casting has replaces steel frames for vacuum chambers for semiconductor production. Several thick aluminum castings were manufactured using chill with temperature measurements. The castings were inspected using 3D computed tomography in order to quantify the porosity defect density in the castings. Effects of the thickness of the chill on the porosity defect density were discussed.

비정질 As-Ge-Te 박막의 물리적 성질 및 스위칭 특성 (The physical properties and switching characteristics of amorphous As-Ge-Te thin film)

  • 이현용;천석표;이영종;정홍배
    • 대한전기학회논문지
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    • 제44권7호
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    • pp.901-907
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    • 1995
  • The switching characteristics of As$_{10}$ Ge$_{15}$ Te$_{75}$ thin film were investigated under d.c. bias. And the frequency dependence of the conductivity was analysed with regard to the temperature dependence, in order to find the physical properties of the As$_{10}$ Ge$_{15}$ Te$_{75}$ thin film ; a characteristic relaxation time (.tau.$_{0}$ ), the spatial density of defect states (N), and the localized wavefunction (.alpha.$^{-1}$ ). It was formed that the threshold voltage depends on thickness, electrode distance, annealing time and temperature, respectively. The threshold voltage is increased as the thickness and the electrode distance is increased, while the threshold voltage is decreased in proportion to the increased annealing time and temperature.

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TEM Stud of GaN Thick Film Crystals Grown by HVPE

  • 송세안;이성국
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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    • pp.121-121
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    • 1999
  • Gallium nitride (GaN) semiconductor is intensively under investigation for commercialization of short wavelength light emitting devices and laser diodes. One of serious obstacles to overcome is to reduce the defect density in GaN film grown by various techniques such as MOCVD, HVPE, etc. Many research groups including SAIT are trying to improve the defect density to 106-107/cm2 from the level of 108-1010/cm2. We have investigated epitaxial growth behaviour of GaN thin and thick films under hidride vapour phase epitaxy (HVPE) condition. In this report, we present the microstructural and crystallographical characteristics of the GaN films grown on sapphire (0001) substrate which were studied by both conventional and high-resolution transmission electron microscopy (TEM). Also we present some microscopic analysis results obtained from GaN films grown by ELO(dpitzsial lateral overgrowth)-HVPE and from GaN quantum well structures grown by MOCVD. Another serious problem in growing GaN thick film by HVPE is internal micro-cracks. We also comment the origin of the micro-crack.

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Czochralski법으로 성장시킨 LiNbO3 단결정의 결함구조 : Dislocation Etch Pits Morphology (Defect Structures in LiNbO3 Single Crystals Grown by Czochralski Method : Dislocation Etch Pits Morphology)

  • 장동석;오근호
    • 한국세라믹학회지
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    • 제26권5호
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    • pp.661-669
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    • 1989
  • The defect structure in LiNbO3 single crystals grown by Czochralski method from the congruently melting composition were investigated. Chemical etching patterns were studied in x-plane, z-plane, and major cleavage plane, respectively, dislocation density was higher at the periphery of crystals than at the center because the thermal stress due to radial temperature gradient had a main effect on it, as compared with dislocations formed from the solid-liquid interface. Many dislocation lineages were arranged along several directions.

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소각중성자 산란법을 이용한 도금층의 극미세 균열 형상의 비파괴적 분석 (Non-destructive Analysis of Nano-sized Crack Morphology of Electro-deposit by Using Small Angle Neutron Scattering)

  • 최용;신은주;한영수;성백석
    • 한국표면공학회지
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    • 제49권2호
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    • pp.111-118
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    • 2016
  • A method to quantitatively analyze the defects formed by the hydrogen evolution during electroplating was suggested based on the theoretical approach of the small angle neutron scattering technique. In case of trivalent chrome layers, an isolated defect size due to the hydrogen evolution was about 40 nm. Direct and pulse plating conditions gave the average defect size of about 4.9 and $4.5{\mu}m$ with rod or calabash shape, respectively. Current density change of the pulse plating from $1.5A/dm^2$ to $2.0A/dm^2$ enlarged the average defect size from 3.3 to $7.8{\mu}m$. The defect morphology like rod or calabash was originated by inter-connecting the isolated defects. Small angle neutron scattering was useful to quantitatively evaluate defect morphology of the deposit.

초소형 고집적 모바일 커넥터부품 구조해석 (Structural Analysis of High-Density Mobile Micro-Connector)

  • 전용준;신광호;허영무
    • Design & Manufacturing
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    • 제9권2호
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    • pp.1-5
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    • 2015
  • Recently, as small-sized display products such as mobile phones and digital cameras have become lighter and smaller, the size of electric signal delivery part, connector for the mobile display products, also, needs to become smaller, so high-density integration like shortening the distance between signal delivery media, conductors is necessary. With the micro and high-density integration of the connector, it is necessary to maintain contact to a certain degree for keeping intensity and delivering electric signal smoothly to prevent a defect with a specific impact. Accordingly, this study carried out a structural analysis according to the operating mechanisms of 0.16CHP Class Bottom Contact FPC Connector and 0.24CHP Class BTB Connector mostly used in small-sized mobile display products such as mobile phones and digital cameras. As a result of the analysis, both connectors had lower than 997MPa, yield strength of connector material C5240-XSH, so it is judged that permanent plastic deformation would not occur, and that a contact force between the connector and FPC film occurs to a certain degree, so that there would not be any defect in electric signal delivery.

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온도보상용 세라믹 커패시터의 전기적 특성에 관한 연구 (A study on electrical characteristics of ceramics capacitor for temperature compensation)

  • 홍경진;정우성;김태성;이은학;이준웅
    • E2M - 전기 전자와 첨단 소재
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    • 제8권5호
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    • pp.640-647
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    • 1995
  • In this study, the BaTiO$\sub$3/ capacitor add to MnO$\sub$2/ like depressor and shifter were investigated for temperature or voltage compensation by structural and electrical analysis. The relative density of BCTM, generating poly crystall and formation of lattice defect, has a 90[%] over as the CaTiO$\sub$3/ come out to control grain size. The current density of BCTM2 increased non-ohmic in high-electric field but that BCTM3 and BCTM4 had a few changing. The BCTM3 and BCTM4 unformated grain boundary shown temperature compensation properties, so that the dielectric constant was low value. The curie point was near 140[.deg. C] in BCTM1 and BCTM4, but BCTM3 and BCTM4 not shown the curie point. It is found that the charging energy of BCTM4 was changed 6[%] according to rising temperature from room temperature to 417[K]. The formation of BaMnO$\sub$3/ was low dielectric constant to change frequency and temperature.

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비정질 게르마늄(a-Ge : H)의 전기전도 활성화에너지 및 결함밀도의 온도의존성 (Temperature Dependence of the Electrical Activation Energy and Defect Density in Undoped Amorphous Germanium (a-Ge : H))

  • 조우성;유종훈
    • 한국재료학회지
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    • 제5권6호
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    • pp.639-643
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    • 1995
  • 수소화된 비정질 게르마늄 (a-Ge : H)에 대해 전기전도율이 297-423K 사이에서 연구되었다. 측정된 전기전도율의 Arrhenius 구성에 의해 pre-exponential 인수 $\sigma$$_{0}$ 및 활성화에너지 $E_{c}$- $E_{F}$가 결정되었다. 튀어오름(kink) 온도의 존재로 인해 전기전도율의 arrhenius 구성이 두 exponential 함수에 의해 표현되었고, 이에 의해 결정된 페르미준위의 통계이동계수 ${\gamma}$$_{F}$는 약 8.65$\times$$10^{-3}$eV/K이었으며, $\sigma$$_{0}$는 약 2$\Omega$$^{-1}$$cm^{-1}$ /이었다. 전기전도율 데이터로부터 결함밀도가 수치해석적 방법에 의해 계산되었고, 결함밀도는 측정된 온도영역하에서 약 2배 정도 변화하였다 변화하였다화하였다

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