• Title/Summary/Keyword: Defect Density

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A Study on the Image Changes of an Eye Shape according to Eyelash Design (속눈썹디자인에 따른 눈 형태의 이미지변화 연구)

  • Park, Jeong Shin
    • Journal of Fashion Business
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    • v.21 no.1
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    • pp.58-73
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    • 2017
  • The purpose of this study was to examine the need of the eyelash design area and the changes of an eye image according to eyelash design. Methodology included both a theoretical research and an empirical research. The theoretical research reviewed previous researches and technical books. The empirical research divided eye shapes, complemented the defect of eye shapes, and examined resulting image changes. A mechanical way was performed for treatment because it was more efficient than a manual way. A J-curl type was used. Eye length was divided into five and the point was determined. The length and density of curl were changed in each point to maximize a treatment effect. As a result, eye images were changed as follows. First, round eyes became stable. Slit eyes became vivid and soft. Wide-set eyes became intelligent and narrow-set eyes became smooth. Large eyes were naturally gradated and small eyes became larger. Double-eyelid eyes became stable and elegant and single-eyelid eyes became gentle and soft. Bulging eyes became easy and soft and sunken eyes became smooth. Peaked eyes became gentle and soft and sleepy eyes became strong and vivid. Based on the findings, eyelash design can play a role in changing an image according to eye shapes. In particular, a speed eyelash extension device to extend eyelash can reduce working hours and gradate only by angle control. It can complement the defect of eyes according to the design of each shape and change into a better image.

Retrospective comparative clinical study for silk mat application into extraction socket

  • Kim, Ju-Won;Jo, You-Young;Kim, Jwa-Young;Oh, Ji-hyeon;Yang, Byoung-Eun;Kim, Seong-Gon
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.41
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    • pp.16.1-16.6
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    • 2019
  • Background: Silk mats have been approved for clinical trials by the Korean Food and Drug Administration as membranes for guided tissue regeneration (GTR). In this study, silk mat application was compared to high-density polytetrafluoroethylene (dPTFE) membrane application or no membrane group. Methods: To compare the silk mat group to the dPTFE group or the no membrane group, a retrospective sample collection was conducted. Bony defects were measured at the time of extraction (T0) and then at 3 months (T1) and 6 months after extraction (T2) on a digital panoramic view. Bone gain (BG) was calculated by subtracting from the bony defect at T0 to the bony defect at each follow-up. Results: The BG at T2 was 2.44 ± 2.49 mm, 4.18 ± 1.80 mm, and 4.24 ± 2.05 mm in the no membrane group, silk mat group, and dPTFE group, respectively. Both membrane groups had significantly higher BG than BG in the no membrane group at T2 (P < 0.05). Conclusions: Both membrane groups showed higher BG than the no membrane group.

Effect of Negative Oxygen Ions Accelerated by Self-bias on Amorphous InGaZnO Thin Film Transistors

  • Kim, Du-Hyeon;Yun, Su-Bok;Hong, Mun-Pyo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.466-468
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    • 2012
  • Amorphous InGaZnO (${\alpha}$-IGZO) thin-film transistors (TFTs) are are very promising due to their potential use in thin film electronics and display drivers [1]. However, the stability of AOS-TFTs under the various stresses has been issued for the practical AOSs applications [2]. Up to now, many researchers have studied to understand the sub-gap density of states (DOS) as the root cause of instability [3]. Nomura et al. reported that these deep defects are located in the surface layer of the ${\alpha}$-IGZO channel [4]. Also, Kim et al. reported that the interfacial traps can be affected by different RF-power during RF magnetron sputtering process [5]. It is well known that these trap states can influence on the performances and stabilities of ${\alpha}$-IGZO TFTs. Nevertheless, it has not been reported how these defect states are created during conventional RF magnetron sputtering. In general, during conventional RF magnetron sputtering process, negative oxygen ions (NOI) can be generated by electron attachment in oxygen atom near target surface and accelerated up to few hundreds eV by self-bias of RF magnetron sputter; the high energy bombardment of NOIs generates bulk defects in oxide thin films [6-10] and can change the defect states of ${\alpha}$-IGZO thin film. In this paper, we have confirmed that the NOIs accelerated by the self-bias were one of the dominant causes of instability in ${\alpha}$-IGZO TFTs when the channel layer was deposited by conventional RF magnetron sputtering system. Finally, we will introduce our novel technology named as Magnetic Field Shielded Sputtering (MFSS) process [9-10] to eliminate the NOI bombardment effects and present how much to be improved the instability of ${\alpha}$-IGZO TFTs by this new deposition method.

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The Effects of Doping Hafnium on Device Characteristics of $SnO_2$ Thin-film Transistors

  • Sin, Sae-Yeong;Mun, Yeon-Geon;Kim, Ung-Seon;Park, Jong-Wan
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.199-199
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    • 2011
  • Recently, Thin film transistors (TFTs) with amorphous oxide semiconductors (AOSs) can offer an important aspect for next generation displays with high mobility. Several oxide semiconductor such as ZnO, $SnO_2$ and InGaZnO have been extensively researched. Especially, as a well-known binary metal oxide, tin oxide ($SnO_2$), usually acts as n-type semiconductor with a wide band gap of 3.6eV. Over the past several decades intensive research activities have been conducted on $SnO_2$ in the bulk, thin film and nanostructure forms due to its interesting electrical properties making it a promising material for applications in solar cells, flat panel displays, and light emitting devices. But, its application to the active channel of TFTs have been limited due to the difficulties in controlling the electron density and n-type of operation with depletion mode. In this study, we fabricated staggered bottom-gate structure $SnO_2$-TFTs and patterned channel layer used a shadow mask. Then we compare to the performance intrinsic $SnO_2$-TFTs and doping hafnium $SnO_2$-TFTs. As a result, we suggest that can be control the defect formation of $SnO_2$-TFTs by doping hafnium. The hafnium element into the $SnO_2$ thin-films maybe acts to control the carrier concentration by suppressing carrier generation via oxygen vacancy formation. Furthermore, it can be also control the mobility. And bias stability of $SnO_2$-TFTs is improvement using doping hafnium. Enhancement of device stability was attributed to the reduced defect in channel layer or interface. In order to verify this effect, we employed to measure activation energy that can be explained by the thermal activation process of the subthreshold drain current.

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The Effects of Current Types on Through Via Hole Filling for 3D-SiP Application (전류인가 방법이 3D-SiP용 Through Via Hole의 Filling에 미치는 영향)

  • Chang, Gun-Ho;Lee, Jae-Ho
    • Journal of the Microelectronics and Packaging Society
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    • v.13 no.4
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    • pp.45-50
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    • 2006
  • Copper via filling is the important factor in 3-D stacking interconnection of SiP (system in package). As the packaging density is getting higher, the size of via is getting smaller. When DC electroplating is applied, a defect-free hole cannot be obtained in a small size via hole. To prevent the defects in holes, pulse and pulse reverse current was applied in copper via filling. The holes, $20\and\;50{\mu}m$ in diameter and $100{\sim}190\;{\mu}m$ in height. The holes were prepared by DRIE method. Ta was sputtered for copper diffusion barrier followed by copper seed layer IMP sputtering. Via specimen were filled by DC, pulse and pulse-reverse current electroplating methods. The effects of additives and current types on copper deposits were investigated. Vertical and horizontal cross section of via were observed by SEM to find the defects in via. When pulse-reverse electroplating method was used, defect free via were successfully obtained.

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Directed Assembly of Block Copolymers for Defect-Free Nanofabrication (블록공중합체 자기조립제어를 통한 무결함 나노구조제작)

  • Shin, Dong-Ok;Jeong, Seong-Jun;Kim, Bong-Hoon;Lee, Hyung-Min;Park, Seung-Hak;Xia, Guodong;Nghiem, Quoc Dat;Kim, Sang-Ouk
    • Korean Chemical Engineering Research
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    • v.46 no.1
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    • pp.1-6
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    • 2008
  • Block copolymers spontaneously assemble into various nanoscale structures such as spheres, cylinders, and lamellar structures according to the relative volumn ratio of each macromolecular block and their overall molecular weights. The self-assembled structures of block copolymer have been extensively investigated for the applications such as nanocomposites, photonic crystals, nanowires, magnetic-storage media, flash memory devices. However, the naturally formed nanostructures of block copolymers contain a high density of defects such that the practical applications for nanoscale devices have been limited. For the practical application of block copolymer nanostructures, a robust process to direct the assembly of block copolymers in thin film geometry is required to be established. To exploit self-assembly of block copolymer for the nanotechnology, it is indispensible to fabricate defect-free self-assembled nanostructure over an arbitrarily large area.

Imaging features of Stafne bone defects on computed tomography: An assessment of 40 cases

  • Morita, Lucas;Munhoz, Luciana;Nagai, Aline Yukari;Hisatomi, Miki;Asaumi, Junichi;Arita, Emiko Saito
    • Imaging Science in Dentistry
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    • v.51 no.1
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    • pp.81-86
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    • 2021
  • Purpose: This study was performed to assess and describe the imaging features of 40 cases of Stafne bone defects (SBDs) on computed tomographic (CT) examinations. Materials and Methods: This study collected data, including age and sex, from 40 patients with SBDs who underwent CT exams. The imaging features of the SBDs were assessed in terms of their location, average size, the relationship of their contour with the cortical plate of the lingual mandible, bone margins, degree of internal density, shape, topographic relationship between the defect and the mandibular edge, the distance from the SBD to the base of the mandible, and the Ariji classification (type I, II, and III). Results: The average age was 57.3 years(range, 28-78 years), and the patients were predominantly male (70%). In all cases (100%), the posterior unilateral lingual SBD variant was observed. Within the Ariji classification, type I was the most common (60%). Among the most frequently observed radiographic characteristics were thick sclerotic bone margin across the entire defect contour, completely hypointense internal content, an oval shape, and continuity with the mandibular base with discontinuity of the mandibular edge. Conclusion: This study showed that posterior SBDs could present with an oval or rounded shape, complete hypodensity, and thick sclerotic margins. Likewise, SBDs could appear almost anywhere, with minor differences from the classic SBD appearance. It is fundamental for dental practitioners to know the imaging features of SBDs, since they are diagnosed primarily based on imaging.

Analysis of Electrical Characteristics due to Deep Level Defects in 4H-SiC PiN Diodes (4H-SiC PiN 다이오드의 깊은 준위 결함에 따른 전기적 특성 분석)

  • Tae-Hee Lee;Se-Rim Park;Ye-Jin Kim;Seung-Hyun Park;Il Ryong Kim;Min Kyu Kim;Byeong Cheol Lim;Sang-Mo Koo
    • Korean Journal of Materials Research
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    • v.34 no.2
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    • pp.111-115
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    • 2024
  • Silicon carbide (SiC) has emerged as a promising material for next-generation power semiconductor materials, due to its high thermal conductivity and high critical electric field (~3 MV/cm) with a wide bandgap of 3.3 eV. This permits SiC devices to operate at lower on-resistance and higher breakdown voltage. However, to improve device performance, advanced research is still needed to reduce point defects in the SiC epitaxial layer. This work investigated the electrical characteristics and defect properties using DLTS analysis. Four deep level defects generated by the implantation process and during epitaxial layer growth were detected. Trap parameters such as energy level, capture-cross section, trap density were obtained from an Arrhenius plot. To investigate the impact of defects on the device, a 2D TCAD simulation was conducted using the same device structure, and the extracted defect parameters were added to confirm electrical characteristics. The degradation of device performance such as an increase in on-resistance by adding trap parameters was confirmed.

Effect of Matrigel for Bone Graft using Hydroxyapatite/Poly $\varepsilon$-caprolactone Scaffold in a Rat Calvarial Defect Model (랫드의 두개골결손부 모델에서 HA/PCL 지지체를 사용한 골이식 시 Matrigel의 효과)

  • Kim, Se-Eun; Shim, Kyung-Mi;Kim, Seung-Eon;Choi, Seok-Hwa;Bae, Chun-Sik;Han, Ho-Jae;Kang, Seong-Soo
    • Journal of Veterinary Clinics
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    • v.27 no.4
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    • pp.325-329
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    • 2010
  • The osteogenic potential of hydroxyapatite/poly $\varepsilon$-caprolactone composite (HA/PCL) scaffolds with matrigel was evaluated in a rat calvarial defect model. Calvarial defect formation was surgically created in Sprague Dawley rats (n = 18). HA/PCL scaffold was grafted with matrigel (M-HA/PCL group, n = 6) or without matrigel (HA/PCL group, n = 6). A critical defect group (CD group, n = 6) did not received a graft. Four weeks after surgery, bone formation was evaluated with radiography, micro computed tomography (micro CT) scanning, and histologically. No bone tissue formation was radiographically evident in the CD group. Bone tissue was radiographically evident in the HA/PCL and M-HA/PCL groups, however, there was more bone-similar opacity in the M-HA/PCL group. Micro CT analysis revealed that the bone volume of the M-HA/PCL group was higher than the HA/PCL group, however, no significant difference was found between the HA/PCL and M-HA/PCL groups. Bone mineral density in the M-HA/ PCL group was significantly higher than in the HA/PCL group (p < 0.05). Histologically, new bone was formed only from existing bone in the CD group, showing concavity without bone formation in the defect. In the HA/PCL group, new bone formation was only derived from existing bone, while in the M-HA/PCL group the largest bone formation was observed, with new bone tissue forming at the periphery of existing bone and around the HA/PCL scaffold with matrigel. The results indicate that the combination of HA/PCL scaffold with matrigel may be an effective means of enhancing bone formation in critical-sized bone defects.

Variation of optical characteristics with the thickness of bulk GaN grown by HVPE (HVPE로 성장시킨 bulk GaN의 두께에 따른 광학적 특성 변화)

  • Lee, Hee Ae;Park, Jae Hwa;Lee, Jung Hun;Lee, Joo Hyung;Park, Cheol Woo;Kang, Hyo Sang;Kang, Suk Hyun;In, Jun Hyeong;Shim, Kwang Bo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.28 no.1
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    • pp.9-13
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    • 2018
  • In this work, we investigated the variation of optical characteristics with the thickness of bulk GaN grown by hydride vapor phase epitaxy(HVPE) to evaluate applicability as GaN substrates in fabrication of high-brightness optical devices and high-power devices. We fabricated 2-inch GaN substrates by using HVPE method of various thickness (0.4, 0.9, 1.5 mm) and characterized the optical property with the variation of defect density and the residual stress using chemical wet etching, Raman spectroscopy and photoluminescence. As a result, we confirmed the correlation of optical properties with GaN crystal thickness and applicability of high performance optical devices via fabrication of homoepitaxial substrate.