• Journal of Veterinary Science
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• 제23권4호
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• pp.62.1-62.10
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• 2022

Background: The corneal and limbal morphology relevant to corneal epithelial maintenance in ten different species was examined using histological methods. Objectives: The presence of a Bowman's layer, limbal epithelial cell, and superficial stromal morphology was examined in the following species to evaluate the differences in corneal thickness and epithelium: Java sparrows, frogs, macaws, spoonbills, red pandas, penguins, horses, Dobermans, orangutans, and humans. Methods: Corneal sections (4 ㎛) were obtained from ten ocular globes from three different animal classes: Aves, Amphibia, and Mammalia. All sections were stained with hematoxylin and eosin and periodic acid-Schiff reaction. After microscopy, all stained slides were photographed and analyzed. Results: Significant morphological differences in the corneal and limbal epithelia and their underlying stroma between species were observed. The number of corneal epithelial cell layers and the overall corneal epithelial thickness varied significantly among the species. The presence of a Bowman's layer was only observed in primates (orangutans and humans). Presumed supranuclear melanin caps were noted in four species (orangutans, macaws, red pandas, and horses) in the limbal basal epithelial layer (putative site of corneal epithelial stem cells). The melanin granules covered the apex of the cell nucleus. Conclusions: Supranuclear melanin capping has been described as a process within the epidermis to reduce the concentration of ultraviolet-induced DNA photoproducts. Similarly, there may be a relationship between limbal stem cell melanin capping as a protective mechanism against ultra-violet radiation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.809-812
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• 1992

Charateristics of the ECR etch were Investigated about $MoSi_2$ layer which is widely used for the capping layer and barrier layer in VLSI metallization. The etch rate was evaluated according to gas ratio of $SF_6/BCl_3$, $N_2$ flow rate, RF power and chamber pressure. The chamber pressure, the most important factor, represented the maximum etch rate at about the pressure of 10 mTorr.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1998년도 IUMRS-ICEM ABSTRACT BOOK
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• pp.127.4-127
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• 1998

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.124-124
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• 2010

Currently, extreme ultraviolet lithography (EUVL) is being investigated for next generation lithography. EUVL is one of competitive lithographic technologies for sub-22nm fabrication of nano-scale Si devices that can possibly replace the conventional photolithography used to make today's microcircuits. Among the core EUVL technologies, mask fabrication is of considerable importance due to the use of new reflective optics having a completely different configuration compared to those of conventional photolithography. Therefore, new materials and new mask fabrication process are required for high performance EUVL mask fabrication. This study investigated the etching properties of SnO2 (Tin Oxide) as a new absorber material for EUVL binary mask. The EUVL mask structure used for etching is SnO2 (absorber layer) / Ru (capping / etch stop layer) / Mo-Si multilayer (reflective layer) / Si (substrate). Since the Ru etch stop layer should not be etched, infinitely high selectivity of SnO2 layer to Ru ESL is required. To obtain infinitely high etch selectivity and very low LER (line edge roughness) values, etch parameters of gas flow ratio, top electrode power, dc self - bias voltage (Vdc), and etch time were varied in inductively coupled Cl2/Ar plasmas. For certain process window, infinitely high etch selectivity of SnO2 to Ru ESL could be obtained by optimizing the process parameters. Etch characteristics were measured by on scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses. Detailed mechanisms for ultra-high etch selectivity will be discussed.

• International Journal of Oral Biology
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• 제37권2호
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• pp.77-83
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• 2012

We investigated the pulpal response to direct pulp capping in rat molar teeth using mineral trioxide aggregate (MTA) and calcium hydroxide (CH). A palatal cavity was prepared in rat maxillary molar teeth. Either MTA or CH was placed on the exposed pulp and all cavities were restored with composite. Rats were sacrificed for histological evaluation after 12 hours and at 2, 7, 14 and 21 days. In both the MTA and CH groups, reparative dentin formation was clearly observed on histology after 14 days. The MTA-capped pulps were found to be mostly free from inflammation, and hard tissue of a tubular consistent barrier was observed. In contrast, in CH-capped teeth, excessive formation of reparative dentin toward residual pulp was evident. The pulpal cell response beneath the reparative dentin layer was examined by immunofluorescence using antibodies against DSP. After 2 days, a few DSP immunopositive cells, most of which showed a cuboidal shape, appeared beneath the predentin layer. At 7 days, DSP-immunopositive cells with columnar odontoblast-like cells were seen beneath the newly formed hard tissues. At 14 and 21 days, DSP was more abundant in the vicinity of the odontoblastic process along the dentinal tubules than in the mineralized reparative dentin. The CH group showed strong expression patterns in terms of DSP immunoreactivity. Our results thus indicate that MTA may be a more effective pulp capping material as it induces the differentiation of odontoblast-like cells and the formation of reparative dentin without the loss of residual pulp functions.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.490.1-490.1
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• 2014

The ZnO nanowire (NW)-based nanogenerators (NGs) can have rectifying current and potential generated by the coupled piezoelectric and semiconducting properties of ZnO by variety of external stimulation such as pushing, bending and stretching. So, ZnO NGs needed to enhance durability for stable properties of NGs. The durability of the metal electrodes used in the typical ZnO nanogenerators(NGs) is unstable for both electrical and mechanical stability. Indium tin oxide (ITO) is used as transparent flexible electrode but because of high cost and limited supply of indium, the fragility and lack of flexibility of ITO layers, alternatives are being sought. It is expected that carbon nanotube and Ag nanowire conductive coatings could be a prospective replacement. In this work, we demonstrated transparent flexible ZnO NGs by using CNT/Ag nanowire hybrid electrode, in which electrical and mechanical stability of top electrode has been improved. We grew vertical type ZnO NW by hydrothermal method and ZnO NW was coated with hybrid silicone coating solution as capping layer to enhance adhesion and durability of ZNW. We coated the CNT/Ag nanowire hybrid electrode by using bar coating system on a capping layer. Power generation of the ZnO NG is measured by using a picoammeter, a oscilloscope and confirmed surface condition with FE-SEM. As a results, the NGs using the CNT/Ag NW hybrid electrode show 75% transparency at wavelength 550 nm and small change of the resistance of the electrode after bending test. It will be discussed the effect of the improved flexibility of top electrode on power generation enhancement of ZnO NGs.

• 한국지반공학회논문집
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• 제19권3호
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• pp.39-44
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• 2003

캡이 설치된 오염된 해성 퇴적층의 압밀침하를 연구하기 위해 원심모형 실험이 실시 되었다. 간극수의 이동을 관측하기 위해 형광색 염료가 사용되었다. 염료이동을 추적한 결과 압밀에 의한 오염원의 이류이동이 확실히 나타났다. 그러므로 압밀에 의한 오염원의 이류이동을 감소시키기 위해 캡핑을 적절하게 설계해야만 한다. 그리고, 원심모형실험 결과와 캡이 설치된 해성 퇴적층의 압밀침하를 예측할 수 있는 PSDDF 프로그램으로 예측된 값이 비교되었다. 원심모형실험결과와 PSDDF 예측치 비교에서 원형시간이 18년 이후에는 원심모형실험 결과와 PSDDF 예측치가 대체로 잘 일치하지만, 원형시간 6년에서 두 결과 사이에 최대 20% 가까운 격차가 나타났다. 그러므로 설계자는 PSDDF 프로그램에 의해 얻은 압밀침하 결과를 사용 시 주의가 요구된다.

• 한국지반공학회논문집
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• 제19권3호
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• pp.33-38
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• 2003

모래를 이용한 해안퇴적층 캡핑은 오염원의 이동을 줄일 수 있는 하나의 방법이다. 캡핑 설계시 자중에 의한 캡 자체의 압밀과 새로 추가된 캡층에 의한 퇴적층의 압밀을 반드시 고려해야만 한다. 이를 위해 원심모형시험기를 이용한 모형실험이 실시되었다. 이 연구에서는 실험의 정확성을 알아보기 위해 모델을 다시 모델링 하는 방법이 이용되었다. 즉, 똑 같은 경계 조건에서 서로 다른 중력가속도를 가지고 실험이 실시 되었다. 두 실험의 결과가 잘 일치함을 알 수 있었다. 이것은 캡이 설치된 해안퇴적층의 압밀침하 거동을 원심모형실험을 이용하여 예측이 가능함을 알 수 있다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.116-116
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• 2010

단일 양자점의 특성 분석 및 이를 활용한 단광자 광원 등으로의 응용에 있어서 표면밀도 및 크기 등이 의도대로 조절된 양자점 성장이 필수적이며, 이와 관련하여 근적외선 파장 영역에서 발광 성분을 갖는 InGaAs/GaAs 양자점 시료를 MEE (Migration Enhanced Epitaxy) 기법으로 성장하였다. 이 때, 30 초 120 초 사이의 migration enhancing time 변화에 의하여 약 $350\;QDs/{\mu}m^2$에서 $3\;QDs/{\mu}m^2$ 사이의 범위로 양자점 표면 밀도가 조절되었으며 양자점의 크기도 변화하는 것을 확인하였다. 별도로 capping layer를 성장하지 않은 양자점 층에 대한 AFM 측정을 통하여 양자점의 크기를 예측하였으나, 실제 시료의 양자점 크기는 capping layer 성장시의 온도 및 압력에 따른 영향이나 물질 조성의 불균일성 등으로 인해 달라질 수 있으므로 비파괴 검사방법인 광발광 측정으로써 실제 양자점의 특성을 검증할 필요성이 존재한다. 먼저 양자점의 크기가 커짐에 따라 기저상태의 에너지 밴드갭 크기가 감소하는 경향이 있음을 확인하였다. 이는 양자점이 클수록 양자구속 효과가 작아지는 일반적인 경향과 일치한다. 또한, 양자점의 크기 차이에 따른 기저상태 및 고차 여기 상태의 에너지 밴드갭 차이의 변화 경향을 분석하였다. 일반적으로 양자점의 크기가 줄어들면 양자구속효과 또한 빠르게 증가하다가 결국에는 에너지 장벽(barrier)의 에너지 준위에서 포화상태에 도달하게 된다. 이러한 양자점 크기에 따른 양자구속효과 크기의 변화는 고차 여기 상태일수록 더욱 빠르며, 결국에는 양자 구속효과가 없어지는 상태(unbound exciton)에 이르기도 한다. 따라서 기저상태의 에너지 밴드갭은 양자점이 커짐에 따라 단조감소 경향을 보이나, 변화율의 차이 때문에 기저상태와 1차 여기상태의 에너지 차이인 level spacing 값은 단조감소 경향이 아닌 종 모양의 경향성을 보이며 측정 결과 또한 이와 일치하였다. 이와 같이 migration enhancing time의 조절로 광자와 상호작용하는 실질적인 양자점의 크기가 의도대로 조절되었음을 비파괴 광측정법으로 확인하였다.

• 한국재료학회지
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• 제33권11호
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• pp.491-496
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• 2023

As the demand for p-type semiconductors increases, much effort is being put into developing new p-type materials. This demand has led to the development of novel new p-type semiconductors that go beyond existing p-type semiconductors. Copper iodide (CuI) has recently received much attention due to its wide band gap, excellent optical and electrical properties, and low temperature synthesis. However, there are limits to its use as a semiconductor material for thin film transistor devices due to the uncontrolled generation of copper vacancies and excessive hole doping. In this work, p-type CuI semiconductors were fabricated using the chemical vapor deposition (CVD) process for thin-film transistor (TFT) applications. The vacuum process has advantages over conventional solution processes, including conformal coating, large area uniformity, easy thickness control and so on. CuI thin films were fabricated at various deposition temperatures from 150 to 250 ℃ The surface roughness root mean square (RMS) value, which is related to carrier transport, decreases with increasing deposition temperature. Hall effect measurements showed that all fabricated CuI films had p-type behavior and that the Hall mobility decreased with increasing deposition temperature. The CuI TFTs showed no clear on/off because of the high concentration of carriers. By adopting a Zn capping layer, carrier concentrations decreased, leading to clear on and off behavior. Finally, stability tests of the PBS and NBS showed a threshold voltage shift within ±1 V.