• 환경위생공학
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• 제6권1호
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• pp.95-102
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• 1991

This study was carried out to determine the contamination level of heavy mentals in canned fishes on the market. Contents of tin, lead, iron and zinc were analyzed by Atomic Absorption Spectrophtometer. Contents of total mercury were determined by mercury analyzer. The results were as follows. 1. The highest value of tin was $1.7706{\pm}0.3216$pprn in canned yellow pin & skip jack(mix) tuna, the lowest was 1.2109 ${\pm}$ 0.0769ppm in canned mackerel pike. 2. The highest value of lead was 0.1657 ${\pm}$ 0.0530 pprn in canned yellow pin tuna, the lowest was 0.0335k 0.0100 pprn in canned mackerel pike. 3. The highest value of iron and zinc was 22.5943 ${\pm}$ 0.7945 ppm and 13.4556 ${\pm}$ 0.6774 pprn in canned sardine fish, the lowest was 4.3514 ${\pm}$ 0.3607 pprn and 3.8773 ${\pm}$ 0.1914 pprn in canned albacore tuna. 4. The total mercury contents was detected 0.0531~0.3386 pprn in three kinds of canned tuna and could not be detected with the others.

• Tribology and Lubricants
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• 제16권1호
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• pp.22-26
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• 2000

In this paper, the fuction of Zinc-dialkyldithiophosphate (ZnDTP) as an oxidation ingibitor of mineral oils was investigated and compared with 2,6-Di-tert-Butyl-4-Methylphenol (DBMP). Oxidation tests were conducted using an oxygen absorption apparatus. ZnDTP showedanti-oxidation property, and length of induction period prolonged by increasing ZnDTP concentration. The anti-oxidation property of ZnDTP was simmilar to that with DBMP. The amount of hydroperoxide decomposition ability with ZnDTP was much greater than that with DBMP, But the rate constant of radical scavenging with ZnDTP was less than that with DBMP. The anti-oxidation property of ZnDTP seems to by both synergy effect of hydroperoxide decomposition ability and radical scavenging ability.

• 한국안전학회지
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• 제31권4호
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• pp.82-89
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• 2016

In this paper, various of experiments were performed for checking the usefulness of Pozzolan Inorganic Polymer(PIP) Waterproof Admixture. The results of the experiment enabled to set the optimum mixture ratio of PIP waterproof admixture as 3.5%. Then, the test specimen mixed with PIP waterproof admixture was produced and consider whether meeting the quality standard of waterproofing admixture for concrete (KS F 4926) From the results, all the items such as mechanical properties and durability were meet the quality standard of KS. The PIP waterproof admixture concrete shows the high resistance of absorption, permeability and chloride ion penetration thanks to its internal components such as siliceous powder, zinc stearate and dispersive polymer.

• 대한치과교정학회지
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• 제5권1호
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• pp.21-24
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• 1975

The purpose of this study was to investigate the effect of sinc phosphate cement on the enamel surface of extracted teeth. The tooth was placed in a test tube, which was subjected to 5ml of 0.2M acetate buffer at pH 4 by 'window technique.' The calcium content of the acetate buffer was determined by the Perkin-Elmer Model 303 Atomic Absorption Spectrophotometer. The obtained results were summarized in the following. 1. The solubility of enamel is $0.92mg/cm^2$. ml in control group. 2. The solubility of enamel is increased by treating these with zinc phosphate cements. 3. The solubility of enamel is $0.69mg/cm^2$. ml by treating with Lee Smith cement. 4. The solubility of enamel is $0.30mg/cm^2$. ml by treating with G-C's cement.

• Journal of Nutrition and Health
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• 제24권6호
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• pp.516-525
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• 1991

In order to investigate whether serum Cu, Zn and Cu/Zn ratio are the useful indicater for the diagnosis of cancer. serum Cu and Zn levels were determined from 35 normal subjects and 33 stomach cancer patients by Atomic absorption spectrophotometer. The following results are obtained : Serum copper levels of stomach cancer patients were significantly increased than the those of the normal controls. whereas serum Zn levels significantly decreased than those of the normal contros(P<0.01) Therefore the copper to zinc ratio revealed a significant in the serum Cu and Zn levels. The serum protein and albumin levels were significantly lower in cancer patients(P<0.01) And the correlation analysis indicated that there was no significant correlation between serum Cu/Zn ratio and protein or albumin. These data suggest that the serum Cu. Zn and Cu/Zn ratio may be used as a diagnostic test in stomach cancer patients.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1235-1241
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• 2012

Aluminium (Al)-doped zinc oxide (AZO) thin films with different Al concentrations were prepared by the solgel spin-coating method. Optical parameters such as the optical band gap, absorption coefficient, refractive index, dispersion parameter, and optical conductivity were studied in order to investigate the effects of the Al concentration on the optical properties of AZO thin films. The dispersion energy, single-oscillator energy, average oscillator wavelength, average oscillator strength, and refractive index at infinite wavelength of the AZO thin films were found to be affected by Al incorporation. The optical conductivity of the AZO thin films also increases with increasing photon energy.

• 환경위생공학
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• 제4권2호
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• pp.101-107
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• 1989

In order to investigate harmful trace in commercial teaproducts. The contents of copper, lead, cadmium, zinc, chromium, manganese and iron were studied in this paper. The samples studied were Youlmoo tea(7) Arrow root tea(9) Ginger tea(4) collected from markets in Seoul area and analysis of seven metals by means of Automic absorption spectrometry. The results obtained were as follows : Lead contents is ranged from 0.06 to 0.72 ppm, cadmium from ND to 0.17 ppm, copper from 0.8 to 16.7 ppm, zinc from 10.4 to 40.4 ppm, manganess from 2.7 to 16.5 ppm, chromium from 0.04 to 4.7 ppm, iron from 7.9 to 55.7 ppm.

• Advances in nano research
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• 제13권5호
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• pp.437-451
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• 2022

Synthesis approaches usually affect the physical and chemical properties of ferrites. This helps ferrite materials to design them for desired applications. Some of these methods are mechanical milling, ultrasonic method, micro-emulsion, co-precipitation, thermal decomposition, hydrothermal, microwave-assisted, sol-gel, etc. These methods are extensively reviewed by taking example of ZnFe₂O₄. These methods also affect the microstructure and local structure of ferrite which ultimately affect the physical and chemical properties of ferrites. Various spectroscopic techniques such as Raman spectroscopy, Fourier Transform Infrared spectroscopy, Ultra Violet-Visible spectroscopy, Mossbauer spectroscopy, extended x-ray absorption fine structure, and electron paramagnetic resonance are found helpful to reveal this information. Hence, the basic principle and the usefulness of these techniques to find out appropriate information in ZnFe₂O₄ nanoparticles is elaborated in this review.

• 한국식품영양학회지
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• 제6권3호
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• pp.219-230
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• 1993

This research aims to study the changes In gastrointestinal function attributed to aging In human. The thresholds for recognition and detection of flavors became elevated and salivary gland acinar cells decreased in the old age. But most esophageal function remained relatively Intact. Although gastric emptying time has been slowed with aging, the total intestinal transit time did not differ. Atropic gastritis due to H. pylori in old man decreased secretion of acid and Intrinsic factor and absorbability of calcium and iron. Pancreatic secretion is droned in older persons. Prevalence of gallstones rised with age. Liver size and portal blood flow decreased significantly with age. Mucosal surface area has been reported to be slightly diminished in the aging man. Glucose transporters decreased and Insulin tolerance Increased. Absorption of aromatic amino acid is diminished with age. Dietary protein In that aging human increased fecal nitrogen excretion. Vitamin A tolerance increased. Vitamin D receptor concentration decreased and resistance to 1,25-(OH)2D3 action increased. Permeability of aging small Intestine Increased. Zinc balance dirt not differ Copper absorption appeared not to be significantly affected by age. Neurotensin secretion decreased thus slowed colonic peristaltic movements and Intestinal mucosal growth.

• 한국산학기술학회논문지
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• 제16권10호
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• pp.6439-6444
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• 2015

지구온난화 방지를 위해 이산화탄소를 제거하는 다양한 방법 중 이산화탄소 포집 및 저장 기술이 가장 유망한 기술로 부각되고 있다. 이산화탄소 포집 및 저장기술이 상용화되기 위해서는 저가의 효율적인 흡수제 개발이 필수적이다. 본 연구에서는 금속 나노입자를 이용하여 이산화탄소 흡수속도를 촉진하는 연구를 수행하였다. 코발트, 아연, 니켈의 세 가지 금속나노입자를 합성하였으며 나노입자 합성 방법 중 습식법과 건식법에 의한 영향을 비교 분석하였다. pH 변화를 이용한 이산화탄소 흡수 속도 측정 결과 습식법으로 제조한 니켈 금속나노입자가 가장 우수한 이산화탄소 흡수 속도 촉진효과를 보였다. 금속 나노입자를 이산화탄소 포집공정에 적용할 경우 흡수탑의 크기를 작게 하여 경제적인 공정 구현이 도움이 될 것으로 기대된다.