• Advances in nano research
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• 제1권2호
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• pp.83-91
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• 2013

The synthesis of semiconductor nanoparticles is a growing research area due to the prospective applications for the development of novel technologies. In this paper we have reported the biosynthesis of Cadmium sulfide nanoparticles (CdSNPs) by reduction of cadmium sulphate solution, using the bacteria of Serratia nematodiphila. The process for the synthesis of CdS nanoparticles is fast, novel and ecofriently. Formation of the CdS nanoparticles was confirmed by surface Plasmon spectra using UV-Vis spectrophotometer and absorbance strong peak at 420 nm. The morphology of crystalline phase of nanoparticles was determined from Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy and X-ray diffraction (XRD) spectra. The average size of CdS nanoparticles was in the range of 12 nm and the observed morphology was spherical. The results indicated that the proteins, which contain amine groups, played a reducing and controlling responsibility during the formation of CdS nanoparticles in the colloidal solution. Antibacterial activity against some bacteria such as Bacillus subtilis, Klebsiella planticola. CdS nanoparticles exhibiting good bactericidal activity.

• 대한치과기공학회지
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• 제34권1호
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• pp.1-9
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• 2012

Purpose: The purpose of this study was to investigate the transmittance differences of pressable ceramic core due to thickness within the visible light spectrum. Methods: 36 specimens were divided into 2 groups (0.6mm, 0.8mm) which have each 3 specimens. The size of specimens was 10mm high and 10mm wide. The transmittance of specimens are measured by spectrophotometer Model Cary 500 that can measure infrared-ray, visible wave and ultraviolet-ray. Results: The results shows that there was no significant difference between specimen's thickness(0.6mm, 0.8mm) and transmittance. Conclusion: The individual's color perception is personal and there are numerous factors that influence on it. In general, human eye can perceive the color of thing only within visible light spectrum but in this experiment through spectrophotometer there was no big difference between specimen's thickness(0.6mm, 0.8mm) and transmittance. To sum up, The most important factors were a layed porcelain structure and its thickness rather than core thickness in the porcelain crown. Also, When making all ceramic core with dead pulp (nervous treatment tooth) when used as a restorative esthetic think is more efficient to improve.

• 한국결정성장학회지
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• 제9권1호
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• pp.23-28
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• 1999

Au 미립자가 분산된 $TiO_{2}$ 박막을 졸겔담금법과 열처리공정으로 실리카 유리기판위에 제조하였다. $TiO_{2}$ 박막제조는 titanium tetraisopropoxide-EtOH-HCl-$H_{2}O$-hydrogen tetrachloroaurat (III) tetrahydrate계를 이용하였다. 고농도로 Au 화합물을 함유하면서 투명한 코팅용액을 형성하는 조건을 검토하였다. Au 금속미립자의 크기를 조절하기 위하여 광환원공정을 채택하였다. UV 조사에 따른 Au 입자의 변화와 $TiO_{2}$ 매트릭스의 상전이과정을 XRD, SEM, TEM and UV-visible spectrophotometer로 관찰하였다. 분산제로서 CPCl (Cetylpyridinium chloride monohydrate)의 효과를 평가하였다.

• 대한치과기공학회지
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• 제37권4호
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• pp.199-203
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• 2015

Purpose: The purpose of this in vitro study was to evaluation the effect of shade on all ceramic restoration based zirconia according to cooling rate on Firing. Methods: 10 specimens applied to the dentin porcelain were made on the zirconia. After 5 specimens of the first group were burned in the furnace, these were put out rapidly. And after 5 specimens of the second group were burned in the furnace, these were put out slowly later 15 min. All specimens were measured $L^*$, $a^*$, $b^*$ using spectrophotometer, there were calculated 10 mean(SD) of descriptive statistics with SPSS program. These data were used for ${\Delta}E^*$ with color difference equation. Independent t tests were performed between 2 groups. Results: $L^*$, $a^*$, $b^*$ of 2 groups was statistically significant respectively (p<0.001), ${\Delta}E^*$ was 4.55 value. Conclusion: This study showed effect of shade on all ceramic restoration based zirconia according to cooling rate on Firing.

• 생명과학회지
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• 제10권3호
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• pp.279-285
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• 2000

cAMP 수용성 단백질인 CRP는 Escherichia coli에서 대사와 관련된 유전자의 전사를 조절한다. 본 연구는 야생형과 돌연변이 CRP 단백질의 열적 안정성과 온도에 따른 단백질의 구조변화를 관찰하기 위 하여 proteolytic digestion, UV spectrophotometer, CD spectrapolarimeter 등의 방법을 사용하였다. cAMP가 없을 때에는 야생형, S83G, S128A CRP가 열적 안정성에서 큰 차이를 보이지 않았지만, cAMP가 존재할 때 야생형 CRP가 다른 돌연변이 CRP보다 열적으로 더욱 안정함을 보였다. 그리고 protease digestion 실험을 통하여 높은 온도에서 cAMP의 존재와 무관하게 돌연변이 CRP에서 단백질 의 변성으로 인한 절단된 단백질띠를 관찰할 수 있었다. 그리고 55$^{\circ}C$에서 측정한 CD 스펙트럼에서 단백 질의 2차 구조인 $\alpha$-helix 구조가 부분적으로 파괴되었음이 관찰되었다.

• 대한치과기공학회지
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• 제33권2호
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• pp.129-136
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• 2011

Purpose: The purpose of this study was to investigate the transmittance differences of zirconium core due to thickness within the visible light spectrum. Methods: 36 specimens were divided into 3 groups (0.6mm, 0.8mm, 1.0mm) which have each 12 specimens. The size of specimens was 10mm high and 10mm wide. The transmittance of specimens are measured by spectrophotometer Model Cary 500 that can measure infrared-ray, visible wave and ultraviolet-ray. Results: The results shows that there was no significant difference between specimen's thickness and transmittance. Conclusion: The individual's color perception is personal and there are numerous factors that influence on it. In general, human eye can perceive the color of thing only within visible light spectrum but in this experiment through spectrophotometer there was no big difference between specimen's thickness and transmittance. To sum up, The most important factors were a layed porcelain structure and its thickness rather than core thickness in the porcelain crown.

• 한국전기전자재료학회논문지
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• 제22권7호
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• pp.584-588
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• 2009

Layered ZnS/$CaF_2$/ZnS/Cu film was deposited on glass substrate by using evaporation method. ZnS and $CaF_2$ were chosen as high and low refractive materials. Cu was used as mid-reflective layer. Reflectance with different optical thickness of $CaF_2$ ranging from $0.25{\lambda}\;to\;0.5{\lambda}$ were systematically investigated by using spectrophotometer. In order to expect the experimental results, the simulation program, the Essential Macleod Program(EMP) was adopted and compared with the experimental data. Based on the results taken by spectrophotometer, the ZnS/$CaF_2$/ZnS/Cu multi-layered thin film show the maximum reflectance of 80% at 625nm $(0.25{\lambda}\;in\;CaF_2)$ and 42% at 660nm $(0.5{\lambda}\;in\;CaF_2)$ respectively. As compared with the experimental results and simulation data, it was confirmed the experimental data is well matched with the EMP data.

• Journal of Biosystems Engineering
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• 제33권3호
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• pp.210-215
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• 2008

The objective of this study was to develop models to predict SCC (somatic cell count) in unhomogenized milk by visible and near-infrared (NIR) spectroscopic technique. Total of 100 milk samples were collected from dairy farms and preserved to minimize propagation of bacteria cells during transportation. Reductive reagents such as methyl red, methylene blue, bromcresol purple, phenol red and resazurin were added to milk samples, and then colors of milk were changed based on SCC of milk. For optimal reductive reagents, reaction time was controlled at 3 level of reaction time. A spectrophotometer was used to measure reflectance spectra from milk samples. The partial least square (PLS) models were developed to predict SCC of unhomogenized milk. The PLS results showed that milk samples with reductive reagents had a good correlation between predicted and measured SCC at 5 minutes of reaction time in the visible range. The PLS models with resazurin reagent had the best performance in $400{\sim}600\;nm$. The prediction results of milk samples with resazurin had 0.86 of correlation coefficient and 14,184 cell/mL of SEP.

• 한국안광학회지
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• 제4권2호
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• pp.57-63
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• 1999

소의 수정체의 광투과, 흡수 Spectrum을 Spectrophotometer로 200-800nm 영역에서 측정하였다. 자외선 A-B선 모두 흡수되고 400nm 영역에서 광투과 edge가 나타나고, edge 영역보다 큰 파장에서는 완전투과형 filter가 되었다. 특히 $4^{\circ}C$-$60^{\circ}C$온도에서 광흡수 투과율의 온도조성은 없었다. 박막 설계로부터 long-pass edge filter형인 $n_0/(0.5H)L(LH)^6(0.5H)/n_s$와 $n_0{\mid}(0.5LH0.5L)^kL/1.25{\mid}4.0$ 박막 구조가 소의 수정체 광투과 Spectrum과 일치함을 알 수 있었다. 인공수정체, 안내렌즈의 설계시 박막구조 설계를 추가함으로써 자외선 차단 역할을 할 수 있다.

• 한국안광학회지
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• 제6권2호
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• pp.59-63
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• 2001

대비 민감도를 측정할 대비 휘도는 두 편광 판의 회전과 spectrophotometer로 측정한 가시광 영역의 투과율 면적(T%nm)을 이용하였다. 2개의 contrast 값으로부터 contrast sensitivity(Cs) 계산은 평균 contrast, $L_{max}$ 및 ${\theta}_{max}$ 값을 일정하게 한 후 $L_{min}$ ${\theta}_{min}$값을 계산하여 얻었다. 실험결과 $L_{max}=4000(T%nm)$, ${\theta}_{max}=44.1^{\circ}$로 고정시키고, Cs값이 2.5 및 100에서 $L_{min}$값은 각각 1333, 2666 및 3920(T%nm)이고, ${\theta}_{min}$값은 각각 56.6, 54.3 및 $45^{\circ}$이다.