• Title/Summary/Keyword: Bath Composition

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The corrosion behavior of galvanized steel sheets at the cut edges (용융아연도금강판의 단면부 부식특성)

  • 남궁성;허보영
    • Journal of the Korean institute of surface engineering
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    • v.34 no.4
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    • pp.297-302
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    • 2001
  • As GA (Hot dip galvannealed steel sheet) has good corrosion resistance, weldability and paintability as well as excellent formability, it's demand is rapidly increasing for automotive panels. The GA coated layers are composed of several kinds of brittle Fe-Zn Metallic compounds which are susceptible to powdering during the press forming, however, very careful controls of manufacturing conditions such as galvannealing heat-treatment or bath composition are essential to meet with the required quality of automotive use. In this study the required characteristics of automotive panel are practically surveyed in detail and the appropriate manufacturing conditions of galvannealing or bath composition have experimentally investigated by using the various analyzing and simulating equipments. The result in this study indicated that the corrosion resistance at the cut edges was improved by increasing of coating weight and decreasing of thickness of sheet steels.

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Composition and microstructure of Lead-Tin alloy electrodeposits (납-주석합금 도금층의 조성 및 조직특성)

  • 예길촌;지창훈
    • Journal of the Korean institute of surface engineering
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    • v.34 no.2
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    • pp.151-160
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    • 2001
  • The composition and the microstructure of the lead-tin alloy electrodeposited in a gluconate bath were invesitigated according to electrolysis conditions. The tin content of the lead-tin alloy electrodeposits increased with increasing current density and EDTA addition, while it decreased with increasing temperature and sodium gluconate concentration. The preferred orientation of the alloy deposits changed from the (220) plane through (200) to (200) + (111) planes with increasing cathode overpotential. The surface morphology of the films was closely related to both the preferred orientation and the alloy composition.

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Effect of Heat Treatment on Biochemical Characteristics of Pacific Oyster Crassostrea gigas (열처리에 의한 굴(Crassostrea gigas)의 영양성분 변화)

  • Shim, Kil Bo;Kim, Mina;Park, Kunbawui;Son, Kwangtae;Lim, Chi Won
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.48 no.6
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    • pp.876-882
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    • 2015
  • The aim of this study was to investigate changes in the biochemical characteristics of the Pacific oyster Crassostrea gigas in response to boiling water bath ($85^{\circ}C$, $100^{\circ}C$) and autoclaving ($100^{\circ}C$) heat treatments for 5, 10, 15, and 20 min. The weight loss (7.6-9.5%) of oysters exposed to a $100^{\circ}C$ boiling water bath for 15 min was lower compared to those receiving no treatment. Oysters exposed to the $100^{\circ}C$ boiling water bath for 20 min lost 27.8% of their total weight. The $100^{\circ}C$ autoclaving treatment resulted in weight loss of 13.0-26.1%, with the highest weight loss occurring after 10 min of treatment (26.1%). Heat-treated oysters had significantly higher levels of crude lipid and crude protein relative to untreated oysters (P<0.05). In the heat-treated oysters, total amino acids (including proline and glutamic acid) were increased, but they were decreased by the 20-min $100^{\circ}C$ boiling water bath and autoclaving treatments. The fatty acid composition of oysters was not significantly affected by the water bath heat treatment, but oysters treated with $100^{\circ}C$ autoclaving for 20 min had decreased polyunsaturated fatty acids. Oysters exposed to the water bath heat treatment had significantly increased vitamin A content, but $100^{\circ}C$ autoclaving for 20 min was associated with reduced vitamin A content, as compared to all of the other heat treatments. Therefore, oysters were affected by heat treatment, undergoing metamorphosis and weight loss, but nutrient quality did not change significantly compared to controls, except with the 20-min $100^{\circ}C$ boiling water bath and autoclaving treatments.

The Effect of Balneotherapy on Obesity Index and Body Composition on Obese Children (온천요법이 비만 아동의 비만지수와 체성분에 미치는 영향)

  • Kang, Ki Yeon;Ahn, Taek Won;Han, Jae Kyung
    • The Journal of Pediatrics of Korean Medicine
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    • v.27 no.3
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    • pp.29-40
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    • 2013
  • Objectives The purpose of this study is to evaluate the effect of hot spring bath in obese children. Methods The study was conducted with 20 obese children whose BMI were over 20 ($kg/m^2$). The hot spring bath program was performed in the hot-spring facilities with temperature of $32{\sim}36^{\circ}C$. The children bathed four times from June to July, 2012. Prior to their bath, their heights, weights, and body compositions were measured every time. They were also confirmed their obesity index and obesity degree during the program. Results After the bathing program, degree of obesity has changed, three obesity judgment index (BMI, RI and OI) of the children have decreased (BMI, RI, OI on the $1^{st}$ day: $25.99{\pm}3.47$, $177.63{\pm}17.43$, $37.74{\pm}13.42$; on the $4^{th}$ day: $25.06{\pm}3.08$, $168.4{\pm}14.8$, $30.60{\pm}12.12$), so have body fat mass and percent body fat (BFM, PBF on the $1^{st}$ day: $21.83{\pm}7.03$, $38.24{\pm}3.36$; on the $4^{th}$ day:$19.55{\pm}6.35$, $34.20{\pm}3.77$), but skeletal muscle mass has increased (SMM on the $1^{st}$ day: $18.37{\pm}4.24$ ; on the $4^{th}$ day: $19.80{\pm}4.44$). Conclusions This study shows that hot spring bath could be an effective way of managing and treating obesity.

Zn-Cr Alloy Plating from Acidic Chloride Bath: Effect of Temperature and Current Densities on Composition of Electrodeposits (산성염화욕에서의 Zn-Cr합금도금 : 합금화에 미치는 전류밀도와 온도의 영향)

  • Kang, Soo Young
    • Journal of the Korea Convergence Society
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    • v.9 no.11
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    • pp.285-290
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    • 2018
  • The steel has been used in modern industry, car maker and electric appliance. The steel have some problem, specially corrosion problem. To solve corrosion problem, Zn electrodeposit on steel have been adapted. Recently, The modern industry asks to increase corrosion resistance. Naturally, Increasing corrosion resistance increases the thickness of Zn electrodeposit. But increasing thickness of Zn electrodeposit has some problems. In making part, There are some crack. This crack cause to decrease corrosion resistance. To solve this problem, it is interested in Zn Based alloy electrodeposit such as Zn-Cr. Here, the influence of the electrolytic conditions on the composition of the alloy plating in the chloride bath was investigated. The results are explained by the cathode overvoltage curve of Cr and Zn. As the current density of the cathode increases, Zn content of electrodeposit decrease and Cr content of electrodeposit increase. As the temperature of the electrolyte increases, Zn content of electrodeposit decrease and Cr content of electrodeposit increase.