• Journal of the Korean Chemical Society
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• v.36 no.1
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• pp.51-56
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• 1992

X-ray diffraction analysis and infrared spectrophotometry were used to investigate the crystal structures and the bonding characteristics in $Pb(Zr_{1-y}Ti_y)O_3$ (PNZT), which has a perovskite structure. As $Pb^{2+}$ of PZT was substituted by 8${\sim}$12 atom% $Nd^{3+}$ ion, the structures were changed to cubic from tetragonal and its transmission had maximum value. Transmission increased as the stretching force constant $(k_s)$ of unit cell increased. It is supposed that the electro-optic characteristics might occur due to electron-transition from HOMO to LUMO of titanium ion.

• Restorative Dentistry and Endodontics
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• v.17 no.2
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• pp.287-306
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• 1992

The amounts of copper, mercury, silver, tin, and zinc released from conventional, dispersed phase and spherical high copper content amalgam immersed in artificial saliva soln. for periods of 2 hours, 1 day, 7 days, 30 days has been measured using Neutron Activation analysis and Atomic Absorption Spectrophotometry. The second electron image and EDX of the surface of samples immersed in artificial saliva were observed using SEM. The following results were obtained. 1. The dispersed non-$\gamma_2$ amalgam released more Hg, Ag than the $\gamma_2$-amalgams. Later a decrease of the release rate could be observed. 2. The dispersed high copper amalgam released more copper than low-copper amalgam and the release rate was decreased with time. But the amounts of copper released from Tytin increased with time. 3. Zinc was released all the experiment time. 4. EDAX showed that surface was composed of Ca,P, Sn, Ag, Zn, and Cu, but C1 was not detected. 5. The discontinued destructed surface was observed from the polished amalgam surface. High copper amalgam was destructed more than low copper amalgam.

• Korean Journal of Materials Research
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• v.28 no.9
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• pp.516-521
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• 2018

Copper oxide thin films are deposited using an ultrasonic-assisted spray pyrolysis deposition (SPD) system. To investigate the effect of substrate temperature and incorporation of a chelating agent on the growth of copper oxide thin films, the structural and optical properites of the copper oxide thin films are analyzed by X-ray diffraction (XRD), field-emssion scanning electron microscopy (FE-SEM), and UV-Vis spectrophotometry. At a temperature of less than $350^{\circ}C$, three-dimensional structures consisting of cube-shaped $Cu_2O$ are formed, while spherical small particles of the CuO phase are formed at a temperature higher than $400^{\circ}C$ due to a Volmer-Weber growth mode on the silicon substrate. As a chelating agent was added to the source solutions, two-dimensional $Cu_2O$ thin films are preferentially deposited at a temperature less than $300^{\circ}C$, and the CuO thin film is formed even at a temperature less than $350^{\circ}C$. Therefore the structure and crystalline phase of the copper oxide is shown to be controllable.

• The Korean Journal of Zoology
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• v.2 no.1
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• pp.11-16
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• 1959

가물치(Ophice phalus argus)의 안구망막에 존재하는 시각물질을 spectrophotometry 한 결과 다음과 같다. (1) 암순응된 가물치 안구망막에서 2 % digitonin 으로 시각물질을 추출하여 광조사전의 흡광 spectrum을 측정한 결과 흡광 maximum 은 350$\mu\textrm{m}$, 420$\mu\textrm{m}$, 550$\mu\textrm{m}$, 590$\mu\textrm{m}$에 있으며 있었으며 광조사후의 흡광 spectrum과의 difference spectrum 의 흡광 maximum 은 390$\mu\textrm{m}$, 427 $\pm$2$\mu\textrm{m}$, 550$\mu\textrm{m}$, 595$\mu\textrm{m}$에 있었다. (2) 가물치 망막중의 시각물질인 390$\mu\textrm{m}$, 427$\mu\textrm{m}$, 550$\mu\textrm{m}$, 595$\mu\textrm{m}$의 삼원색광에 대한 감광도는 다음과같다. a. 390$\mu\textrm{m}$은 blue light > red light = green light > white light . b.427$\mu\textrm{m}$ 은 red light >blue light > white light > green light c. 550 $\mu\textrm{m}$과 595$\mu\textrm{m}$ 은 blue light > red light > green light > white light (3) 390 $\mu\textrm{m}$ 과 427$\mu\textrm{m}$에서 흡광 spectrum의 maximum을 가지는 시각물질은 그 존재를 예시하던 새로운 색소이다. (4) 가물치의 시각물질은 증류수에도 용출되나 2 % digitonin 수용액으로 추출하였을때보다 명확하지 못하였다. (5) 가물치는 담수어임에도 불구하고 거북류와 같이 visual voilet 는 발견할 수 없었다.

• Korean journal of food and cookery science
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• v.32 no.4
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• pp.383-389
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• 2016

Purpose: This study was conducted to evaluate the effect of rehydration and subsequent heating at high temperature on the pigments and antioxidants of dried samnamul (Aruncus dioicus) and daraesoon (Actinidia arguta). Methods: Rehydration included 16 h-soaking in cold water, and 30 min-boiling and 1 h-infusion in water. Rehydrated samnamul and daraesoon were heated at $180^{\circ}C$ for 10 or 20 min with or without perilla oil addition (10%) for cooking. Pigments and antioxidants were determined by HPLC and spectrophotometry. Results: Rehydration caused decreases in pigment and polyphenol contents, but increase in tocopherol content. Cooking by heating without addition of perilla oil resulted in increases in chlorophyll and carotenoid contents, but decreases in polyphenol and tocopherol contents. Decrease in tocopherol content by heating at $180^{\circ}C$ was reversed by the addition of perilla oil. Conclusion: This study strongly suggested that cooking of samnamul and daraesoon at $180^{\circ}C$ with perilla oil could improve color, texture, and potential health functionality by recovering the loss of antioxidants and pigments with antioxidant activity.

• Journal of Microbiology and Biotechnology
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• v.22 no.6
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• pp.780-787
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• 2012

The maize pathogen Gibberella moniliformis produces fumonisins, a group of mycotoxins associated with several disorders in animals and humans, including cancer. The current focus of our research is to understand the regulatory mechanisms involved in fumonisin biosynthesis. In this study, we employed a proteomics approach to identify novel genes involved in the fumonisin biosynthesis under nitrogen stress. The combination of genome sequence, mutant strains, EST database, microarrays, and proteomics offers an opportunity to advance our understanding of this process. We investigated the response of the G. moniliformis proteome in limited nitrogen (N0, fumonisin-inducing) and excess nitrogen (N+, fumonisin-repressing) conditions by one- and two-dimensional electrophoresis. We selected 11 differentially expressed proteins, six from limited nitrogen conditions and five from excess nitrogen conditions, and determined the sequences by peptide mass fingerprinting and MS/MS spectrophotometry. Subsequently, we identified the EST sequences corresponding to the proteins and studied their expression profiles in different culture conditions. Through the comparative analysis of gene and protein expression data, we identified three candidate genes for functional analysis and our results provided valuable clues regarding the regulatory mechanisms of fumonisin biosynthesis.

• Journal of the Korean Applied Science and Technology
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• v.10 no.2
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• pp.65-72
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• 1993

The kinetics of the addition of thiourea to cinnamenylisophorone derivatives(X : H, p-Br, $p-CH_3$ $m-CH_3$, $p-OCH_3$) was investigated using ultraviolet spectrophotometry in 20%(v/v) dioxane-$H_2O$ at $25^{\circ}C$. A rate equation which can be applied over wide pH range(pH $1.0{\sim}13.0$) was obtained. In order to investigate the substituent effects of cinnamenylisophorone derivatives. Hammett constant was plotted. As the result, the rate of uncleophilic addition of thiourea to cinnamenylisophorone derivatives was facilitated by electron donating group. It was found that addition of neutral thiourea which was not dissociated at the pH $1.0{\sim}9.0$ was proceeded, the reaction was proceeded by addition of dissociated anion of thiourea above the pH 10.0. On the basis of this kinetic study, the reaction mechanism of nucleophilic addition of thiourea was investigated.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.147-147
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• 2016

In general, organic electrochromic (EC) materials have been known to be electrochemically unstable during the ionic exchange process. One effective method to realize stable EC materials is incorporating graphene derivatives in the polymer matrix, by using the strong interaction between graphene derivatives and polymer. However, previous studies are limited graphene derivatives. In this study, we developed a polymer-graphene derivative complex with the chemical assistance of a surfactant (octadecylamine, ODA). Surfactant-assisted graphene oxide (GO-ODA) was introduced as a protective layer on the electrochromic poly (3-hexyl thiophene) (P3HT) films by the Langmuir-Schaefer method. The deposition of GO-ODA protective layer with high coverage was confirmed by atomic force microscopy. The strong interactions between GO-ODA and P3HT were examined with UV-Vis spectrophotometry and X-ray photoelectron spectroscopy. Electrochemical and electrochromic investigations revealed that the GO-ODA layer greatly improved the long-term cyclability of the P3HT film. These findings imply that the GO-ODA complex has a significant role in creating stable EC cycling, due to its strong interaction with the P3HT film.

• Journal of the Korean Chemical Society
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• v.43 no.4
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• pp.401-406
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• 1999

Trace amount of cadmium was quantitatively extracted with 1% Aliquat 336-MIBK from 0.2M KSCN and 0.01M-HCl. Test tubes with a screw cap stopper were used for extraction in place of conventional separating funnels and organic solvents used were less dense than water. In this analysis, 22 times concentration effect was achieved with higher selectivity without interference. The detection limit of cadmium was 0.7ppb, therefore trace cadmium was easily analyzed by this method. The proposed method was applied to the determination of cadmium in blood serum and extraction mechanism was elucidated.

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.504-509
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• 2013

In this study, ZnSe-$TiO_2$ composites were synthesized by a facile hydrothermal-assisted sol-gel process and characterized by nitrogen adsorption isotherms (77 K), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM) and UV-vis diffuse reflectance spectrophotometry. The photocatalytic activity was investigated by decoloration methylene blue (MB), methyl orange (MO), and rhodamine B (Rh.B) in an aqueous solution under visible light irradiation. The results revealed that the photocatalytic activity of the ZnSe-$TiO_2$ photocatalyst was much higher than that of pure$TiO_2$. The ZnSe nanoparticles, which act as a photosensitizer, not only extend the spectral response of $TiO_2$ to the visible region but also reduce charge recombinations.