• 한국표면공학회지
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• 제36권2호
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• pp.176-184
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• 2003

New lubricant film of organic and inorganic composite resin was developed to improve the press formability of galvannealed steel sheets (GA) for automotive body panels. The frictional coefficient of lubricant GA steel sheets is about 20% superior to that of uncoated GA. The current range of spot welding of lubricant GA is similar to that of the uncoated GA, but the burning trace of spot welding is inferior to that of the uncoated GA in the oiling condition. The alkaline degreasability of lubricant GA shows 100% in alkaline degreasing condition of automotive company. The size and shape of the phosphated coating layer are similar to those of the uncoated GA sheet. The powdering property of the lubricant GA gives rise to 20∼50% improved property compared with the uncoated GA sheet.

• 한국표면공학회지
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• 제25권2호
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• pp.57-65
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• 1992

Increasing demands of high corrosion resistant sheet steels for the automotive body panels have been leading to a tendency toward heavier coatings of electroplated sheet steels. The specimens were prepared from lab-scale electroplating simulator with various coating weights of zinc, zinc-iron and zinc-nickel coated sheet steels and evaluated in the light of the application for the automotive body panels. Corrosion resistances by sacrificial action were improved with increasing coating weights for all electroplated sheet under survey, but blistering resistances of pure zinc coated sheet steels were not as much. On the other hand, the adhesions of heavy alloy coatings showed poor powdering performances by the external compressive or tensile forces.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.23-24
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• 2018

Reinforced concrete is a building material that is generally used in modern society. Also, reinforced concrete structures in high salinity environments have low durability due to corrosion of reinforcing bars due to infiltrated chlorine ions. Anion exchange resins have an ability to immobilize chlorine ions in the resin while releasing their anions. As a material, it has already been shown that it is possible to fix the chloride ion inside the cementitious material through the cement mortar experiment. The purpose of this study is to confirm the compressive strength of cement mortar using powdered anion exchange resin after powdering an anion exchange resin. In order to confirm the chloride ion fixation ability of the powder anion exchange resin, chlorine ion penetration resistance test was carried out.

• 한국표면공학회지
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• 제34권4호
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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.

• 한국표면공학회지
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• 제28권5호
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• pp.320-328
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• 1995

The electroplated steel sheets were heated during the short periods(10~60 seconds) at high temperature ($360^{\circ}C$～$500^{\circ}C$) in order to investigate thermal diffusion behaviors. When the steel sheets were heated for 10 seconds, all the coated layers were alloyed at $420^{\circ}C$ but at temperature lower than $400^{\circ}C$ the $\eta$ phase partially remained on the coated surface. At higher temperature, the longer the time for heat treatment the iron contents were increased in coated layer but the glossiness and whiteness of the coated surface were decreased. While the alloying phases of $\eta$, $\zeta$, $\delta_1$ and $\Gamma$ were appeared in the coated layer at the heat treatment temperature of $360^{\circ}C$, the phase was disappeared at $420^{\circ}C$ but the rests grew in size at the temperature of $440^{\circ}C$. When the heat treatment temperature and heating time were increased, the thickness of $\Gamma$ phase was rapidly increased to 0.8 $\mu\textrm{m}$. The optimum conditions for the heat treatment to prevent powdering of coated layer were obtained to heat it for 30 seconds at $400^{\circ}C$ and 10 seconds at $440^{\circ}C$, and the iron content in coated layer was suited to be 10 percents.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1575-1578
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• 2005

As GA(Galvannealed sheet steel, GA) has good corrosion resistance, weldability and paintability as well as excellent stamping formability it's demand is rapidly increasing for automotive panel. But the layer of the Galvannealed sheet steel is easy to have a coating layer such as powdering and flaking in the press process because it is composed of Fe-Zn alloy. Therefore, the process condition is properly required to form the surface treated sheet steel. The frictional characteristics with dies are changed according to the annealing temperature, $505^{\circ}C,\;515^{\circ}C\;and\;540^{\circ}C$ during the process. To obtain the frictional characteristics of GA sheet steel in this study, on flat friction test is conducted. The friction coefficient is compared with the variation of pressure and velocity, viscosity of lubricant at the various galvannealed temperatures.

• 한국잠사곤충학회지
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• 제43권1호
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• pp.41-48
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• 2001

The purification, dissolution and powdering of stained waste silk obtained from weaving and dyeing process were studied for the surface modification of textile fabric and plastic materials. The whiteness of stained waste silk could be improved through degumming and bleaching with sodium hydrosulfite. The water-soluble fibroin solution can be obtained by dissoving the degummed waste silk in a boiling solution of 50% calcium chloride for 60 minutes. The salts and heavy metals contained in fibroin solution were removed by electric dialysis, wool fiber filtration and gel filtration chromatography. The fibroin powder was prepared by using a fine grinder after the alkali treatment for weakening the silk fiber. The fine fibroin powder of particle size around 30 ㎛ was obtained with a ultra fine-mill, while it was finer below 10 ㎛ with a ball-mill. The dissolved or powdered silk was applied to the surface of fabric with addition of the binder (a urethane resin). The moisture content of polyester and nylon fabrics treated with the silk solution was improved due to hygroscopic property of silk. The fine fibroin powder mixed with the binder ws coated on the surface of synthetic film by use of the air pressed sprayer. It was revealed that the hygroscopicity as well as the softness of fibroin powder coated film was much improved. Therefore, it is thought that the fine silk fibroin powder is applicable as an coating agent for the surface modification of plastic and synthetic leather.

• Corrosion Science and Technology
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• 제10권1호
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• pp.1-5
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• 2011

The major purpose of the present study is to evaluate the performance of various galvanized (GI) or galvannealed (GA) mild steels and AHSS in stamping applications. Finite Element Analysis (FEA) of selected stamping operations was conducted to estimate the critical pressure boundary conditions that exist in practice. Using this information, laboratory tribotests, e.g. Twist Compression (TCT), Deep Drawing (DDT) and Strip Drawing (SDT) Tests, were developed to evaluate the performance of selected lubricants and die materials/coatings in forming galvanized steels of interest. The sheet materials investigated included mild steels and AHSS (e.g. DP600 GI/GA, DP780 GI/GA, TRIP780 GA and DP980 GI/GA). Experimental results showed that galvanized material resulted in more galling, while galvannealed material showed more powdering and flaking. The surface roughness and chemical composition of galvanized sheet materials affected the severity of galling under the same testing conditions, i.e. lubricants and die materials/coatings. The results of this study helped to determine the critical interface pressure that initiates lubricant failure and galling in stamping selected galvanized sheet materials. Thus, to prevent or postpone the critical interface conditions, the results of this study can be used to select the optimum combination of galvanized sheet, die material, die coating and lubricant for forming structural automotive components.

• 대한본초학회지
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• 제38권4호
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• pp.31-43
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• 2023

Objectives : The objective of this study was to investigate the phytochemistry and pharmacological activities of Cirsium setidens. Methods : Domestic and international articles about Cirsium setidens were investigated. A review was perfoemed via DB searching engine such as Sci.Direct, Springer, DBpia, KISS, Google scholar, Kipris, and so on. Total 73 listed literature were classified by compound analysis and pharmacological efficacy. Results : C. setidens contains pectolinarin and its glycoside, pectolinarigenin as index compounds, and linarin, apigenin, diosmetin, scopoletin, acacetin, cirsimarin, cirsimaritin, setidenosides A and B, silymarin, hispidulin, 92 volatile compounds, and 15 fatty acids. The Pharmacological activities of C. setidens has been reported to inhibit of platelet aggregation and fat accumulation in the liver, inhibit to hepatitis, anti-cancer, antibacterial, skin improvement, hair growth, liver protection, anti-diabetic, anti-inflammatory, sedative. Also, It has been reported the effect of cholesterol-lowering and anti-obesity, neuroprotective effects, increasing human stem cell viability, inhibiting osteoclast formation and osteogenic differentiation. Conclusion : This reviews showed that C. setidens which has been traditionally used for the treatment of inflammation and hypertension, has anticancer and river protective effect, as well as hair loss and diet. In order to maximize the efficacy of C. setidens, research has also begun on the effect of processing processes such as fermentation or fine powdering and combining natural plant resources.

• 한국식품위생안전성학회지
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• 제15권3호
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• pp.248-251
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• 2000

본 연구는 ESR spectroscopy를 이용하여 계란의 방사선 조사여부와 조사선량에 따른 ESR신호의 크기 및 신호의 안정성을 알아보았다. 신선한 계란을 0, 0.5, 1, 2, 3그리고 5 kGy로 방사선을 조사한 후, 난백과 난황 및 내막을 제거한 겉껍질만을 이용하여 신호의 특성을 알아보았다. 실험결과 방사선 조사된 계란은 g$_1$=2.0023$\pm$0.00004, g$_2$=1.9979$\pm$0.00005에서 특유의 비대칭적인 ESR신호를 나타내어 비조사 시료와 확실하게 구별되었으며, 조사선량의 증가에 따른 ESR신호에 대한 회귀식은 y=2.23$\times$10${^7}$x (r${^2}$=0.9661)로서 조사선량에 따라 ESR신호의 크기는 비례적으로 증가하였다. 또한 이들 신호의 크기는 상온과 5$^{\circ}C$이하에서 77일간의 저장기간 후에도 안정하게 남아있어 방사선 조사여부의 판별은 장기간의 저장에서도 가능하였다. 따라서 ESR spectroscopy를 이용한 방사선 조사 계란의 검지방법은 빠르고 확실하며 정량적인 방법으로써 유용한 검지기술임을 알 수 있었다.