• 대한임상검사과학회지
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• 제46권1호
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• pp.1-11
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• 2014

This research has been performed by our own investigation, also cooperated with Health and Sanification Division and each of district offices in Busan metropolitan city. After choosing, we collected water samples five times for microbiological examination. As a result of investigating in 160 water samples from urban areas, we could detect 88 cases of Vibrio spp. Furthermore, there were four cases exceeding the acceptable limit of aquarium water (100,00/mL) and another four cases exceeding the limit of Coliform group (1,000 below/100 mL). As a result of investigating that we performed for 271 cases of water samples from coastal areas from April to November, we could detect 130 cases of vibrio species and 10 cases of Coliform group. After performing 17 kinds of antibiotic susceptibility test for 41 cases of isolated Vibrio parahaemolyticus, 27 cases showed tolerance to Amplicllin (AM), all of 31 cases showed intermediate resistance only to Cefazolin (CF) but had sensitivity to the rest of them. As a result of performing antibiotic susceptibility test, serum test and PFGE gene analysis on each 10 pair of Vibrio parahaemolyticus detected concurrently from intake-pipe water and, aquarium water, we couldn't get data showing that they are clearly same species in three kinds of test. In addition, UV sterilization, Ozonization and so on. Based on our research, intake pipe didn't have a problem with microbiological contamination so we are sure that the germ came from supplied fish had caused that kind of contamination. For effective management, UV sterilization or Ozonization which can be handled consistently should be adopted in aquarium.

• 대한금속재료학회지
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• 제46권2호
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• pp.88-96
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• 2008

Thermal evaporated 10 nm-$Ni_{50}Co_{50}$/(70 nm-poly)Si films were deposited to examine the energy saving properties of silicides formed by rapid thermal annealing at temperature ranging from 500 to $1,100^{\circ}C$ for 40 seconds. Thermal evaporated 10 nm-Ni/(70 nm-poly)Si films were also deposited as a reference using the same method for depositing the 10 nm-$Ni_{50}Co_{50}$/(70 nm-poly)Si films. A four-point probe was used to examine the sheet resistance. Transmission electron microscopy (TEM) and X-ray diffraction XRD were used to determine cross sectional microstructure and phase changes, respectively. UV-VIS-NIR and FT-IR (Fourier transform infrared spectroscopy) were used to examine the near-infrared (NIR) and middle-infrared (MIR) absorbance. TEM analysis confirmed that the uniform nickel-cobalt composite silicide layers approximately 21 to 55 nm in thickness had formed on the single and polycrystalline silicon substrates as well as on the 25 to 100 nm thick nickel silicide layers. In particular, nickel-cobalt composite silicides showed a low sheet resistance, even after rapid annealing at $1,100^{\circ}C$. Nickel-cobalt composite silicide and nickel silicide films on the single silicon substrates showed similar absorbance in the near-IR region, while those on the polycrystalline silicon substrates showed excellent absorbance until the 1,750 nm region. Silicides on polycrystalline substrates showed high absorbance in the middle IR region. Nickel-cobalt composite silicides on the poly-Si substrates annealed at $1,000^{\circ}C$ superior IR absorption on both NIR and MIR region. These results suggest that the newly proposed $Ni_{50}Co_{50}$ composite silicides may be suitable for applications of IR absorption coatings.

• 복식
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• 제50권7호
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• pp.33-46
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• 2000

Uniform is the dress of distinctive design or fashion worn by members of a particular group or serving as a means of identification. The postman's uniform of Ministry of Communication should be distinctive or characteristic clothing to provide high functionality and symbolization of job characteristics, cost effectiveness and esthetic. In order to design the postman's new uniform available in 2000, there has been a satisfaction survey to 1,116 postmen. A thorough analysis of survey and informal and face-to-face discussion with postmen give the direction of design concept. One of the most important things in the design concept is to make the uniform high quality & refinement. The style is a refined jumper suit in consideration of form stability, wearing satisfaction, convenience in activity. The basic colors selected are navy and medium gray. The colors of jumper are MOC red ; C.I color Green : a representative color of youth, white : a symbolic color of bright future. All three colors are plaid on a basic nary color. In the selection of the textile, synthetic fiber (Polyester 65%, rayon 35%) equipped with UV cutting as well as water resistance etc. was recommended. In the uniform design process, the effective communication with user (postman) is critical to find the requirements and needs of uniform user (postman). Also. the uniform designer should reflect the above four key factors in design development. Therefore, the uniform should provide the user with high job performance and job pride in wearing the uniform.

• 폴리머
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• 제25권5호
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• pp.625-634
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• 2001

액상 이소프렌 고무에 무수 말레간(MAH)을 그라프팅시킨 후 2,2,6,6-tetramethyl-4-piperidinol (TMPO)를 반응시켜 hindered amine light stabilizer (HALS)가 함유된 새로운 고분자형 광안정제를 합성하고, SBR에 대한 광안정제로서의 특성을 관찰하였다. 새로운 고분자형 광안정제의 조성과 물리적 성질은 적정법, GPC 그리고 열중량 분석에 의하여 분석하였다. SBR의 광산화 반응에 대한 고분자형 광안정제의 효과를 254nm 자외선 조사에 따른 자외선 흡광도의 변화, 관능기 변화 그리고 잔막율로서 관찰한 결과, 새로운 고분자형 광안정제를 첨가함으로써 광산화 반응이 효과적으로 억제되었다. 또한, 고부자형 광안정제의 추출내성은 저분자량의 모델 화합물에 비하여 훨씬 우수하였으며, 고분자형 광안정제와 SBR의 상용성은 TMPO가 SBR 필름 표면에 균일하게 고루 분산되어 있어서 매우 우수하였다.

• 한국재료학회지
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• 제17권6호
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• pp.323-330
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• 2007

We fabricated thermaly evaporated 10 nmNi/(poly)Si films to investigate the energy saving property of silicides formed by rapid thermal annealing (RTA) at the temperature of $300{\sim}1200^{\circ}C$ for 40 seconds. Moreover, we fabricated $10{\sim}50$ nm-thick ITO/Si films with a rf-sputter as reference films. A four-point tester was used to investigate the sheet resistance. A transmission electron microscope (TEM) and an X-ray diffractometer were used for the determination of cross sectional microstructure and phase changes. A UV-VISNIR and FT-IR (Fourier transform infrared rays spectroscopy) were employed for near-IR and middle-IR absorbance. Through TEM analysis, we confirmed $20{\sim}70nm-thick$ silicide layers formed on the single and polycrystalline silicon substrates. Nickel silicides and ITO films on the single silicon substrates showed almost similar absorbance in near-IR region, while nickel silicides on polycrystalline silicon substrate showed superior absorbance above 850 nm near-IR region to ITO films. Nickel silicide on polycrystalline substrate also showed better absorbance in middle IR region than ITO. Our result implies that nano-thick nickel silicides may have exellent absorbing capacity in near-IR and middle-IR region.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.445.1-445.1
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• 2014

Dye-sensitized solar cells (DSSCs) have been widely investigated as a next-generation solar cell because of their simple structure and low manufacturing cost. The $TiO_2$ film with thickness of $8{\sim}10{\mu}m$, which consists of nanoparticles, acts as both a scaffold with a high surface-to-volume ratio for the dye loading and a pathway to remove the electrons. However, charge carriers have to move across many particle boundaries by a hopping mechanism. So, one dimensional nanostructures such as nanotubes, nanorods and nanowires should improve charge carrier transportation by providing a facile direct electron pathway and lowering the diffusion resistance. However, the efficiencies of DSSCs using one dimensional nanostructures are less than the $TiO_2$ nanoparticle-based DSSCs. In this work, the patterned $TiO_2$ film with thickness of $3{\mu}m$ was deposited using photolithography process to decrease of electron pathway and increase of surface area and transmittance of $TiO_2$ films. Properties of the patterned $TiO_2$ films were investigated by various analysis method such as X-ray diffraction, field emission scanning electron microscopy (FESEM) and UV-visible spectrophotometer.

• 한국전기전자재료학회논문지
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• 제19권5호
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• pp.442-449
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• 2006

Electrical, optical, and structural properties of indium zinc oxide (IZO) films grown by a box cathode sputtering (BCS) were investigated as a function of oxygen flow ratio. A sheet resistance of $42.6{\Omega}/{\Box}$, average transmittance above 88% in visible range, and root mean spare roughness of $2.7{\AA}$ were obtained even in the IZO layers grown at room temperature. In addition, it is shown that electrical characteristics of the top-emitting organic light emitting diodes (TOLEDs) with the BCS grown-IZO top cathode layer is better than that of TOLEDs with DC sputter grown IZO top cathode, due to absence of plasma damage effect. Furthermore the effects of oxygen flow ratio in IZO films are investigated, based on x-ray photoelectron spectroscopy (XPS), ultra violet/visible (UV/VIS) spectro-meter, scanning electron microscopy (SEM), and atomic force microscopy (AFM) analysis results.

• Journal of Electrochemical Science and Technology
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• 제9권4호
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• pp.308-319
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• 2018

Single step electrodeposition of $Cu_2ZnSnS_4$ (CZTS) for solar cell applications was studied using an aqueous thiocyanate based electrolyte. The sodium thiocyanate complexing agent was found to decrease the difference in the deposition potential of the elements. X-ray diffraction analysis of the samples indicates the formation of kesterite phase CZTS. UV-vis studies reveal the band gap of the deposits to be in the range of 1.2 - 1.5 eV. The thickness of the deposit was found to decrease with increase in pH of the electrolyte. Nearly stoichiometric composition was obtained for CZTS films coated at pH 2 and 2.5. I-V characterization of the film with indium tin oxide (ITO) substrate in the presence and the absence of light source indicate that the resistance decrease significantly in the presence of light indicating suitability of the deposits for solar cell applications. Results of electrochemical impedance spectroscopic studies reveal that the cathodic process for sulfur reduction is the slowest among all the elements.

• 대한소아치과학회지
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• 제23권3호
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• pp.640-658
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• 1996

The purpose of this study was to examine the mechanism of improving acid resistance of Nd-YAG laser irradiated tooth enamel and determine the most effective energy density for improving acid resistance. The bovine tooth enamel were lased with a pulsed Nd-YAG laser. The energy densities of exposed laser beam were varied from 10 to $70\;J/cm^2$. To investigate the degree of improving acid resistance by irradiation, all the samples were submerged to demineralize in 0.5 N $HClO_4$ solution for 1 minute. After 1 minute, 0.05 % $LaCl_3$ was added to the solution for interrupting the demineralization reaction. The amounts of dissolved calcium and phosphate in the solution were measured by using an atomic absorption spectrophotometer and the UV/VIS spectrophotometer, respectively. To examine the mechanism of improving acid resistance, X-ray diffraction analysis, infrared spectroscopy, and scanning electron microscopy were taken. The X-ray diffraction pattern of the samples were obtained in the $10^{\circ}{\sim}80^{\circ}2{\theta}$ range with $Cu-K{\alpha}$ radiation using M18HF(Mac Science Co.) with X-ray diffractometer operating at 40 KV and 300 mA. The infra-red spectra of the ground samples in 300 mg KBr pellets 10 mm diameter were obtained in the $4000cm^{-1}\;to\;400cm^{-1}$ range using JASCO 300E spectrophotometer. The scanning electron microscopy was carried out using JSM6400(JEOL Co.) with $500{\sim}2000$ times magnification. The results were as follow 1. The concentration of calcium dissolved from laser irradiated enamel with $50J/cm^2$ was significantly lesser than that of unlased control group (p<0.05) 2. From the result of the X-ray diffraction analysis, $\beta$-TCP, which increases acid solubility, was identified in lased enamel but the diffraction peaks of (002) and (004) became sharp with increasing energy density of laser irradiation. This means that the crystals in lased samples were grown through the c-axis and subsequently, the acid solubility of enamel decreased. 3. The a-axis parameter was slightly increased by laser irradiation, whereas the c-axis parameter was almost constant except for a little decrease at $50J/cm^2$. 4. In the infra-red spectra of lased enamels, phosphate bands ($600{\sim}500cm^{-1}$), B-carbonate bands (870, $1415{\sim}1455cm^{-1}$), and A-carbonate band ($1545cm^{-1}$) were observed. The amounts of phosphate bands and the B-carbonate bands were reduced, on the other hand, the amount of the A-carbonate band was increased by increase the energy density. 5. The SEM experiments reveal that the surface melting and recrystallization were appeared at $30J/cm^2$ and the cracks were observed at $70J/cm^2$. From above results, It may be suggested that the most effective energy density for improving acid resistance of tooth enamel with the irradiation of Nd-YAG laser was $50J/cm^2$. The mechanism of improving acid resistance were reduction of permeability due to surface melting and recrystallization of lased enamel and reduction of acid solubility of enamel due to decrease of carbonate content and growth of crystal.

• 한국미생물·생명공학회지
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• 제46권2호
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• pp.120-126
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• 2018

환경친화적으로 항균성이 부여된 상처치료용 BC 드레싱을 개발하기 위한 기초연구로서, 은 이온에 대해 내성이 있으면서 은 나노입자를 생합성할 수 있는 초산균을 분리 및 동정하였다. 나아가 실험균주에 의한 BC 생산 조건을 조사하였다. 부패된 포도껍질로부터 분리된 G7 균주는 0.1 mM $AgNO_3$ 존재 하에서 생육할 수 있었으며, 16S rRNA 유전자의 염기서열 분석에 의거하여 Acetobacter intermdius로 동정되었다. 탄소원으로 2% glucose, 질소원으로 2% yeast extract, 보조탄소원으로 0.115% acetic acid가 함유된 배지에서 BC 생산량이 최대였다. 최적배지에서 생성된 BC의 구조적 특성을 FT-IR 및 XRD를 사용하여 조사한 결과, 생성된 BC는 전형적인 천연 cellulose와 동일한 cellulose I인 것으로 확인되었다. G7 균주를 0.1 mM $AgNO_3$ 가 함유된 최적 배지에서 배양한 결과, 배양액의 색깔이 적갈색으로 변하였으며, 이것은 은 나노입자가 생성되었음을 의미한다. 은 나노입자의 합성유무를 UV-Vis 스펙트럼 분석에 의하여 확인한 바, 425 nm에서 은 나노입자의 고유한 흡수스펙트럼이 관찰되었다. 또한, 생성된 BC를 주사전자현미경으로 관찰한 결과, 표면과 기공에 은 나노입자가 생성되어 있음을 재확인하였다.