• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.134-134
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• 2012

We investigated the interface of poly (3-hexylthiophene) (P3HT) and C61-butyric acid methylester (PCBM) by using photoelectron spectroscopy (PES). These are the most widely used materials for bulk heterojunction (BHJ) organic solar cells due to their high efficiency. Study of the BHJ interfaces is difficult because the organic films are typically prepared by spin coating in ambient conditions. This is incompatible with the interface electronic structure probes such as PES, which requires ultrahigh vacuum conditions. Study of interface requires gradual deposition of thin films that is also incompatible with the spin coating process. In this work, we used electrospray vacuum deposition (EVD) technique to deposit P3HT and PCBM in high vacuum conditions. EVD allows us to form polymer thin films onto ITO substrate in a step-wise manner directly from solutions and to use PES without exposing the sample to the ambient condition. Although the morphology of the EVD deposited P3HT films observed by optical and atomic force microscopes is quite different from that of the spin coated ones, the valence region spectra were similar. PCBM was deposited on the P3HT film in a similar manner and the energy level alignment between these two materials was studied. We discuss the relation between Voc of P3HT:PCBM solar cell and HOMO-LUMO energy offset obtained in this study.

• 생체재료학회지
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• 제22권4호
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• pp.352-359
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• 2018

Background: Black phosphorus (BP) has emerged as a novel class of nanomaterials owing to its unique optical and electronic properties. BP, a two-dimensional (2D) nanomaterial, is a structure where phosphorenes are stacked together in layers by van der Waals interactions. However, although BP nanodots have many advantages, their biosafety and biological effect have not yet been elucidated as compared to the other nanomaterials. Therefore, it is particularly important to assess the cytotoxicity of BP nanodots for exploring their potentials as novel biomaterials. Methods: BP nanodots were prepared by exfoliation with a modified ultrasonication-assisted solution method. The physicochemical properties of BP nanodots were characterized by transmission electron microscopy, dynamic light scattering, Raman spectroscopy, and X-ray diffractometry. In addition, the cytotoxicity of BP nanodots against C2C12 myoblasts was evaluated. Moreover, their cell imaging potential was investigated. Results: Herein, we concentrated on evaluating the cytotoxicity of BP nanodots and investigating their cell imaging potential. It was revealed that the BP nanodots were cytocompatible at a low concentration, although the cell viability was decreased with increasing BP nanodot concentration. Furthermore, our results demonstrated that the cells took up the BP nanodots, and the BP nanodots exhibited green fluorescence. Conclusions: In conclusion, our findings suggest that the BP nanodots have suitable biocompatibility, and are promising candidates as fluorescence probes for biomedical imaging applications.

• 한국재난정보학회 논문집
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• 제18권4호
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• pp.847-860
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• 2022

연구목적: 본 논문은 자가발전기반을 통한 항만구조물의 건전성 모니터링 시스템 개발에 대한 기초연구이다. 연구방법: 자가발전 시스템 개발 및 해수용 광섬유(FBG)센서 개발로 항만구조물 건전성 모니터링 시스템 구축에 대한 기초연구 데이터를 제공한다. 연구결과: 일조량 시뮬레이션 분석을 통해 국내환경에서 4-5시간의 일조량 확보가 가능하며, 이를 통해 해수적용이 가능한 광섬유센서의 Raw 데이터를 수집하는 광분배기(인트로게이터), 수집된 데이터를 연산하는 MCU와 무선 통신기능이 탑재된 IoT 모듈, 모니터링 서버부로 송신하는 Gateway로 구성된 장치에 대한 전원공급이 가능한 시스템을 구축하였다. 결론: 광섬유(FBG)센서를 통한 항만구조물의 직접적인 거동에 대한 센싱 모니터링 구축과 이를 위한 자가발전시스템 적용의 가능성을 확인하였다.

• Applied Microscopy
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• 제51권
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• pp.4.1-4.12
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• 2021

Fluorescence in situ hybridization (FISH) is a technique to visualize specific DNA/RNA sequences within the cell nuclei and provide the presence, location and structural integrity of genes on chromosomes. A confocal Whole Slide Imaging (WSI) scanner technology has superior depth resolution compared to wide-field fluorescence imaging. Confocal WSI has the ability to perform serial optical sections with specimen imaging, which is critical for 3D tissue reconstruction for volumetric spatial analysis. The standard clinical manual scoring for FISH is labor-intensive, time-consuming and subjective. Application of multi-gene FISH analysis alongside 3D imaging, significantly increase the level of complexity required for an accurate 3D analysis. Therefore, the purpose of this study is to establish automated 3D FISH scoring for z-stack images from confocal WSI scanner. The algorithm and the application we developed, SHIMARIS PAFQ, successfully employs 3D calculations for clear individual cell nuclei segmentation, gene signals detection and distribution of break-apart probes signal patterns, including standard break-apart, and variant patterns due to truncation, and deletion, etc. The analysis was accurate and precise when compared with ground truth clinical manual counting and scoring reported in ten lymphoma and solid tumors cases. The algorithm and the application we developed, SHIMARIS PAFQ, is objective and more efficient than the conventional procedure. It enables the automated counting of more nuclei, precisely detecting additional abnormal signal variations in nuclei patterns and analyzes gigabyte multi-layer stacking imaging data of tissue samples from patients. Currently, we are developing a deep learning algorithm for automated tumor area detection to be integrated with SHIMARIS PAFQ.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.211-211
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• 1999

Titanium nitride (TiN) thin films have useful properties including high hardness, good electrical conductivity, high melting point, and chemical inertness. The applications have included wear-resistant hard coatings on machine tools and bearings, decorative coating making use of the golden color, thermal control coatings for widows, and erosion resistant coatings for spacecraft plasma probes. For all these applications as feature sizes shrink and aspect ratios grow, the issue of good step coverage becomes increasingly important. It is therefore essential to manufacture conformal coatings of TiN. The growth of TiN thin films by chemical vapor deposition (CVD) is of great interest for achieving conformal deposition. The most widely used precursor for TiN is TiCl4 and NH3. However, chlorine impurity in the as-grown films and relatively high deposition temperature (>$600^{\circ}C$) are considered major drawbacks from actual device fabrication. To overcome these problems, recently, MOCVD processes including plasma assisted have been suggested. In this study, therefore, we have doposited Ti(C, N) thin films on Si(100) and D2 steel substrates in the temperature range of 150-30$0^{\circ}C$ using tetrakis diethylamido titanium (TDEAT) and titanium isopropoxide (TIP) by pulsed DC plamsa enhanced metal-organic chemical vapor deposition (PEMOCVD) method. Polycrystalline Ti(C, N) thin films were successfully grown on either D2 steel or Si(100) surfaces at temperature as low as 15$0^{\circ}C$. Compositions of the as-grown films were determined with XPS and RBS. From XPS analysis, thin films of Ti(C, N) with low oxygen concentration were obtained. RBS data were also confirmed the changes of stoichiometry and microhardness of our films. Radical formation and ionization behaviors in plasma are analyzed by optical emission spectroscopy (OES) at various pulsed bias and gases conditions. H2 and He+H2 gases are used as carrier gases to compare plasma parameter and the effect of N2 and NH3 gases as reactive gas is also evaluated in reduction of C content of the films. In this study, we fond that He and H2 mixture gas is very effective in enhancing ionization of radicals, especially N resulting is high hardness. The higher hardness of film is obtained to be ca. 1700 HK 0.01 but it depends on gas species and bias voltage. The proper process is evident for H and N2 gas atmosphere and bias voltage of 600V. However, NH3 gas highly reduces formation of CN radical, thereby decreasing C content of Ti(C, N) thin films in a great deal. Compared to PVD TiN films, the Ti(C, N) film grown by PEMOCVD has very good conformability; the step coverage exceeds 85% with an aspect ratio of more than 3.