• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.381-382
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• 2008

$TiO_2$ colloidal solution was electrosprayed for preparing a conductive thin film with high quality. Electrospray is a technique of liquid dispersion electrically and a good method of manufacturing nanoparticle, nanofiber, porous membrane, film preparation and coating. Water and ethanol were used as solvents and their mixing ratio was varied for studying the influence of solvent volatile on nanoparticle dispersion. Various nozzles to control the thru-put of solutions.were examined. Integrated analytical method and scanning electron microscope were used to analyze integrity and microscopic images.

• Transactions on Electrical and Electronic Materials
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• 제7권4호
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• pp.173-179
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• 2006

Due to the limitations of the channel length, the lateral spread for two-dimensional impurity distributions is critical for the analysis of devices including the integrated complementary metal oxide semiconductor (CMOS) circuits and high frequency semiconductor devices. The developed codes were then compared with the two-dimensional implanted profiles measured by transmission electron microscope (TEM) as well as simulated by a commercial TSUPREM4 for verification purposes. The measured two-dimensional TEM data obtained by chemical etching-method was consistent with the results of the developed analytical model, and it seemed to be more accurate than the results attained by a commercial TSUPREM4. The developed codes can be applied on a wider energy range $(1KeV{\sim}30MeV)$ than a commercial TSUPREM4 of which the maximum energy range cannot exceed 1MeV for the limited doping elements. Moreover, it is not only limited to diffusion process but also can be applied to implantation due to the sloped and nano scale structure of the mask.

• Applied Microscopy
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• 제26권2호
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• pp.105-121
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• 1996

투과전자현미경을 이용한 최근의 재료 분석기술에 대해 일본 토호쿠대학의 ASMA (Atomic Scale Morphology Analysis) 연구실에서 얻은 실험결과를 중심으로 설명하였다. 현재 토호쿠대학에서 가동 중에 있는 가속전압 1250 kV의 초고압 투과전자현미경은 분해능이 약 0.1nm이며, 이 전자현미경으로부터 얻은 고분해능상은 대형컴퓨터를 이용한 시뮤레이션에 의해 해석 할 수 있음을 나타내었다. 또한, 이러한 뛰어난 고분해능 특성을 가진 초고압 투과전자현미경과 최근 재료 분야의 전자현미경 시료 제작기술의 하나로서 크게 주목받고 있는 초박절편법 (Ultramicrotomy)을 이용한 헤마타이트 미립자의 내부구조 해석 결과를 나타내었다. 새로운 전자현미경 분석기법을 위한 주변장비의 눈에 띄는 발달중의 하나로서 전자현미경상을 디지탈 형태로 기록하고, 이를 효과적인 화상처리 기법으로 해석할 수 있는 Imaging Plate (IP)를 주목할 수 있다. 본 논문에서는 IP의 응용 예로서 IP를 이용하여 기록한 고분해능 전자현미경상과 전자 회절패턴의 정량해석 결과에 대해 나타내었다. 에너지분산 X-선 검출기를 이용한 새로운 분석기법의 예로서 전자 채널링 효과를 이용한 ALCHEMI법을 Ni-Al-Mn계 화합물에 대한 실험결과와 함께 나타내었다. 또한, 전자에너지 손실 분광 분석법을 이용한 최근 분석 결과로서 여러 구리 화합물의 전자구조 차이에 따른 구리의 $L_{23}$ 가장자리 피이크 변화를 나타내었다. 새로운 전자현미경법인 에너지 필터를 사용하여 $Al_{0.5}In_{0.5}As$의 전자회절 패턴의 백그라운드를 제거한 결과를 에너지 필터를 사용하지 않은 $Al_{0.5}In_{0.5}As$의 전자회절 패턴과 비교하여 나타내었다.

• 분석과학
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• 제6권5호
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• pp.515-520
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• 1993

Rene 80 주조블레이드가 고온에서 사용중인 사용 온도에 의해 ${\gamma}^{\prime}$이라는 석출물이 기지(${\gamma}^{\prime}$) 내에서 생성되기 때문에 고온강도는 그 석출물에 좌우된다. 즉, 석출물의 격자상수는 기지의 격자상수보다 크기 때문에 석출물이 생성되거나 성장할 때에 ${\gamma}-{\gamma}^{\prime}$ 격자어긋남(lattice misfit)에 의해 전위가 발생한다고 일반적으로 알려져 있다. 이러한 격자어긋남은 석출물(${\gamma}^{\prime}$)의 크기가 클수록 원형${\rightarrow}$사각형${\rightarrow}$판상형으로 바뀌어 가면서 증가한다. 따라서 본 연구에서는 이러한 격자어긋남의 양을 주사투과전자현미경에서 수렴성 빔전자 회절(CBED)을 사용하여 측정하여, 석출물과 인접한 기지의 전위밀도의 증가가 기지 내에서 석출물이 생성하고 성장함에 따른 격자어긋남이 원인인가를 관찰하였다.

• 한국재료학회지
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• 제19권3호
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• pp.151-155
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• 2009

Micro-scale copper bumps for build-up PCB were electroplated using a pulse-reverse method. The effects of the current density, pulse-reverse ratio and brightener concentration of the electroplating process were investigated and optimized for suitable performance. The electroplated micro-bumps were characterized using various analytical tools, including an optical microscope, a scanning electron microscope and an atomic force microscope. Surface analysis results showed that the electroplating uniformity was viable in a current density range of 1.4-3.0 A/$dm^2$ at a pulse-reverse ratio of 1. To investigate the brightener concentration on the electroplating properties, the current density value was fixed at 3.0 A/$dm^2$ as a dense microstructure was achieved at this current density. The brightener concentration was varied from 0.05 to 0.3 ml/L to study the effect of the concentration. The optimum concentration for micro-bump electroplating was found to be 0.05 ml/L based on the examination of the electroplating properties of the bump shape, roughness and grain size.

• 분석과학
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• 제37권4호
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• pp.220-229
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• 2024

This study aims to developing a method for estimating pharmaceutical compounds within a monolith column using high-performance liquid chromatography (HPLC). The monolithic column was prepared using copolymerization of glycidyl methacrylate, co-ethylene dimethacrylate, and co-acrylic acid inside a borosilicate tube of specific dimensions a 60 mm borosilicate tube length with 1.5 mm and 3.5 mm inner and outer diameters, respectively. A UV Ultra violet source with a wavelength of 365 nm was used, and the polymerization process involved mixing glycidyl methacrylate, acrylic acid, ethylene dimethacrylate as a binder, and 2,2-dimethoxy-2-phenyl acetate phenone as an initiator in suitable solvents consisting of ethanol and 1-hexanol. The polymerization process formed the monolith column after 4 minutes, and subsequently, the epoxy groups were altered to diol groups using 0.2 M hydrochloric acid HCl, which were pumped through the column for 3 hours at a flow rate of 10 µL·min^-1. Various techniques, such as Scanning Electron Microscope SEM, Brunauer-Emmett-Teller BET, Fourier-transform infrared spectroscopy FT-IR and HNMR, were utilized to characterize and confirm the structure of the monolith. The prepared monolith was employed to estimate and identify the pharmaceutical compound of warfarin using high-performance liquid chromatography HPLC. The analytical curve of warfarin was linear in the range of 3 to 100 ㎍·mL^-1 with an r² value of 0.999. The detection and quantification limits were 0.932 and 2.788 ㎍·mL^-1, respectively. The molar absorptivity and Sandells sensitivity were 2.99138 × 10⁶ L·mol^-1·cm^-1 and 103.1 × 10^-3 ㎍·cm^-2, respectively.

• 한국세라믹학회지
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• 제47권4호
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• pp.302-307
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• 2010

This study aims to synthesize emerald-green malayaite pigments using $CaCO_3$, $SiO_2$, $SnO_2$ and $V_2O_5$. For this purpose, the optimum composition is $CaV_{0.25}Sn_{0.687}SiO_5$ and heating condition is at $1250^{\circ}C$ for 6 h of soaking time. The samples were characterized by X-ray diffraction (XRD), the Fourier Transform Infrared Spectrometers(FT-IR), the Raman Spectrometer, Scanning Electron Microscope(SEM) and the UV/Vis spectroscopy. The substituted V ion for Sn was observed to be quadrivalence. The analytical results of the synthesized pigment showed the tetragonal crystal, a typical form of Malayaite, and the particle size to be approximately $5{\sim}10\;{\mu}m$. The color in lime glaze added 12 wt% pigment was emerald green, and CIE Lab parameters are $L^*=67.73$, $a^*=-12.39$ and $b^*=9.28$.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.36.2-36.2
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• 2010

A small amount of Na incorporated in $CuInSe_2$ (CIS) absorption layer has become widely accepted as a requirement for efficient polycrystalline CIS solar cells. However, there is ongoing argument on the role of sodium incorporated in the absorber. In this paper, CIS absorption layers have been deposited using the three-stage co-evaporation process on Mo coated non-Alkali glass substrates. The NaF was evaporated during the second-stage with various fluxes. This paper is focusing on differences of micro-structure and composition ratio of the absorber realized with different Na contents and the variation of electrical properties of the cells with the corresponding absorbers. The analytical results of x-ray diffraction (XRD) patterns, field emission scanning electron microscope (FE-SEM), energy dispersive spectroscopy (EDS) and current-voltage characteristics will be discussed to investigate the effect of NaF flux on the CIS absorber formation and its cell performance.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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• pp.231-234
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• 2000

Vertically aligned carbon nanotubes were synthesized on Ni-coated Si substrates using microwave plasma-enhanced chemical vapor deposition. The grain size of Ni thin films was varied with the RF power density during the RF magnetron sputtering process. It was found that the diameter, growth rate, and density of carbon nanotubes could be controlled systematically by the grain size of Ni thin films. With decreasing the grain size of Ni thin films, the diameter of the nanotubes decreased, whereas the growth rate and density increased. High-resolution transmission electron microscope images clearly demonstrated synthesized nanotubes to be multiwalled. The number of graphitized wall decreased with decreasing the diameter. Field emission properties will be further presented.

• Journal of Electrochemical Science and Technology
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• 제11권3호
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• pp.291-309
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• 2020

Chromium was electrodeposited from deep eutectic solvents-based Cr³⁺ electrolytes on HB-pencil graphite electrode. Factors influencing the electrochemical behavior and the processes of Cr nucleation and growth were explored using cyclic voltammetry and chronoamperometry techniques, respectively. Cr³⁺ reduction was found to occur through an irreversible diffusion-controlled step followed by another irreversible one of impure diffusional behaviour. The reduction behavior was found to be greatly affected by Cr³⁺ concentration, temperature, and type of hydrogen bond donor used in deep eutectic solvents (DESs) preparation. A more comprehensive model was suggested and successfully applied to extract a consistent data relevant to Cr nucleation kinetics from the experimental current density transients. The potential, the temperature, and the hydrogen bond donor type were estimated to be critical factors controlling Cr nucleation. The nucleation and growth processes of Cr from either choline chloride/ethylene glycol (EG-DES) or choline chloride/urea (U-DES) deep eutectic solvents were evaluated at 70℃ to be three-dimensional (3D) instantaneous and diffusion-controlled, respectively. However, the kinetics of Cr nucleation from EG-DES was found to be faster than that from U-DES. Cr nucleation was tending to be instantaneous at higher temperature, potential, and Cr³⁺ concentration. Cr nuclei electrodeposited from EG-DES were characterized at different conditions using scanning electron microscope (SEM). SEM images show that high number density of fine spherical nuclei of almost same sizes was nearly obtained at higher temperature and more negative potential. Energy dispersive spectroscopy (EDS) analysis confirms that Cr deposits were obtained.