• Journal of Welding and Joining
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• 제15권1호
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• pp.116-124
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• 1997

A scope of this study is to establish the optimum plasma spray conditions for fine ($5\mu\textrm{m}$) $Al_2O_3$ powder. However, the flowability of the $Al_2O_3$ powder is not so good because of irregular particle shape and fine particle size. Therefore, powder feeding system was modified by 1) change of powder feeding line material from polymer to copper 2) shorten the powder feeding tube length 3) heating the powder feeding system to $80^{\circ}C$4) vibrating the powder feeding line continuously, in order to feed the fine powder homogeneously. The homogeneous powder feeding conditions were obtained with the modified powder feeding system by controlling the powder carrier gas flow and the powder flow rate indicator. The best plasma spraying conditions for the fine $Al_2O_3$ powder were found out as 40kw gun power, 80 g/min. powder feed rate and 50 mm working distance after characterizing the microstructure, hardness and wear loss of the $Al_2O_3$ coating layer.

• Journal of Welding and Joining
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• 제31권4호
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• pp.13-16
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• 2013

In this research, laser cladding characteristics were investigated for various filler metal feeding methods such as powder, cold wire, and hot wire feeding. Appropriate parameter window, deposition rate, material efficiency and dilution for each filler feeding method were evaluated with same laser power and cladding speed range. Laser powder cladding has wider process parameter window but higher material efficiency and lower dilution were achieved by laser wire cladding. Among these feeding methods, laser hot-wire cladding showed best efficiency in material usage and deposition rate.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2001년도 추계학술발표대회 개요집
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• pp.128-131
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• 2001

Laser cladding processing allows rapid transfer of heat to the material being processed with minimum conduction into base metal, resulting in low total heat input. The effects of $CO_2$ laser cladding with powder feeding on mechanical properties of VERSAlloy were studied. Their low melting point (under 1093$^{\circ}C$) enables overlays to be applied with minimum dilution and base metal distortion. Experiment results indicated that powder feeding speed and quantity were important for laser cladding with powder feeding. The powder feeding speed should be adapted according to cladding speed for good shaping of clad layer. The effect of heat on the HAZ size can be limited and the growth of grain size of HAZ size was not serious.

• Journal of Nutrition and Health
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• 제19권1호
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• pp.16-22
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• 1986

This study was designed to investigate the nutritional effect of mugowrt powder supple mentation to rice diets with different protein levels. Thirty female albino rats weighing 39-43g were adopted for the feeding trial for 4 weeks. The different 5 kind of experimental diets were performed . Control diet was commercially available forage for rats, experimental diet (I-C) highly milled rice, (Ⅰ) highly milled rice 95% and mugwort powder 5%, (Ⅱ-C)highly milled rice 95% and milk casein 5%, and (Ⅱ) highly milled rice 90%, milk casein 5 % and mugwort powder 5%. Growth rate was remarkably high in the dietary group fed on highly milled rice supplemented with 5% mugwort powder (protein 8%) (P<0.05), but it showed the tendency to be rather low in the group fed on highly milled rice supplemented with 5% casein and 5% mugwort powder (protein 12%). Food efficiency as well as protein efficiency appeared similar to the growth rate. Hematodcrit level demonstrated the same tendency as growth rate, but hemoglobin content was observed to increase by diets supplemented with increasing amount of mugwort regardless of protein level. Each nutrient intake was increased by adding mugwort powder to diets after a week's feeding, but it was increased by 8% protein diet, and decreased by 12% protein diet in 3 weeks as well as 4 weeks after feeding . The absorption rate of carbohydrate and protein decreased by feeding mugwort supplemented diets regardless of protein level and feeding period, and that of lipid increased with 12% protein diet.

• Journal of Welding and Joining
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• 제35권3호
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• pp.28-34
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• 2017

The authors derived the criteria on the process parameters of laser depositions with metal powers(SUS316L & IN718) by evaluating the surface and cross-section properties of the deposition layers. The surface characteristics of the deposition layer are investigated through optical microscopy by controlling the process parameters of laser output, powder feeding rate and gas feeding rate. The cross-section characteristics were also analyzed after polishing and chemical etching process. As the gas feeding rate increased, the amount of powder loss increased and the difference in the dilution ratio and heat affected zone depending on laser outputs was observed. In addition, the powder feeding rate used in the experiment did not interfere with the energy absorption of the base material.

• Journal of Welding and Joining
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• 제15권4호
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• pp.109-115
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• 1997

Laser cladding is a technique for modification of metal surface. In this laser cladding experiment a metal powder feeding system was developed for more efficient laser cladding. This system can reduce processing time and be used simpler than the conventional method. The feeding of metal powder has given a rise to the process for sequential buildup of bulk rapidly solidified materials in the form of fine powder stream to the laser cladding process. The parameters of laser cladding have been investigated using this experimental equipment. Bronze on aluminum alloy and copper on aluminum alloy were experimented by using defocused beam, powder feeding system, and gas shielding. Good cladding was achieved in the range of beam travel speed of 2.25m/min. In the case of copper/aluminum and bronze/aluminum substrate, the absorption of laser beam was too high to produce low diluted clad. In the case of copper/1050 aluminum, the optimal laser cladding condition was of laser power of 2.8kW, powder feed rate of 0.31g/s and beam travel speed of 2.25m/min. In the case of bronze/aluminum the optimal condition is of laser power of 2.5kW, powder feed rate of 0.31g/s, and beam travel speed of 2.36m/min.

• Journal of Welding and Joining
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• 제19권5호
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• pp.481-485
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• 2001

Laser cladding processing allows rapid transfer of heat to the material being processed with minimum conduction into base metal. The effect of $CO_2$ laser cladding with high viscosity mixed powders was investigated. High viscosity mixed powder consists of bronze powder and flux that is used at a high temperature condition. The mixed powder has a high viscosity that it can be easily pasted over a curved or slope substrate. The device for mixed powder was designed and manufactured. It consists of the high viscosity mixed powder feeding system, the preheating system and the shielding gas system which prevents the clad layer from being oxidized. The results of experiment indicated that the feed rate of high viscosity mixed powder was important for later cladding with mixed powder feeding. The high viscosity mixed powder and substrate must be preheated to prevent porosity from breaking at the clad layer. The experimental result shows that the high viscosity mixed can be applied for laser cladding process.

• Archives of Metallurgy and Materials
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• 제65권4호
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• pp.1365-1369
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• 2020

Direct energy deposition (DED) is a three-dimensional (3D) deposition technique that uses metallic powder; it is a multi-bead, multi-layered deposition technique. This study investigates the dependence of the defects of the 3D deposition and the process parameters of the DED technique as well as deposition characteristics and the hardness properties of the deposited material. In this study, high-thermal-conductivity steel (HTCS-150) was deposited onto a JIS SKD61 substrate. In single bead deposition experiments, the height and width of the single bead became bigger with increasing the laser power. The powder feeding rate affected only the height, which increased as the powder feeding rate rose. The scanning speed inversely affected the height, unlike the powder feeding rate. The multi-layered deposition was characterized by pores, a lack of fusion, pores formed by evaporated gas, and pores formed by non-molten metal inside the deposited material. The porosity was quantitatively measured in cross-sections of the depositions, revealing that the lack of fusion tended to increase as the laser power decreased; however, the powder feeding rate and overlap width increased. The pores formed by evaporated gas and non-molten metal tended to increase with rising the laser power and powder feeding rate; however, the overlap width decreased. Finally, measurement of the hardness of the deposited material at 25℃, 300℃, and 600℃ revealed that it had a higher hardness than the conventional annealed SKD61.

• Journal of Ginseng Research
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• 제15권3호
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• pp.171-178
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• 1991

The results ok feeding experiments to the mice with ginseng extract, ginseng Powder, and ADAPTAGEN, for 30 days before X-ray irradiation and for 40 days after the X-ray irradiation at 750 rads were as follow: 1. The 50% lethals days (LD50, ) by the X-ray irradiation were 9 days at 1, 000 rads. 10 days at 900 rads, 11 days at 800 rads, 14 days at 760 rads, and 19 darts at 750 rads. Therefore, the standard radiation dose was set at 750 radb/8 min. 2. The 80% of the control group mice exposed to the X-ray radiation without ginseng feeding died in periods ranging from 14 to 24 days and the 20~30% of the ginseng extract and ginseng powder feeding groups died. But the 100% of the mice fed with ADAPTAGEN survived. 3. Testicles of the control group became smaller in weight than the nomad group by 26.5 to 29.0% and those of the ginseng extract and ginseng powder feeding group reduced by 44.6 to 60.4%. However, testicles of the ADAPTiIGEN feeding group increased in size by 77.4% to 87.1% and in weight by 61%, showing a recovery phenomenon approarhing to those of the ordinary mice. The ADAPTAGEN feeding group mice were also as active in color as the ordinary ones. 4. An electron micrograph(X8, 000X2.2) of the liver cells of the mice which had been 40 days after X-ray irradiation showed as follows; The control group appeared that is physiological action stopped due to the frequent occurrence of morphological change of the nucleus and diffusion of chromosome, reduction in microspores and expansion of microsomts, and endoplasmic change of mitochondria. The liver cells or the ADAPTAGEN feeding group were in a state similar to those of the ordinary mice restoring to normalcy In contrast, the liver cells of the ginseng extract and ginseng powder feeding groups were still far from being normal. 5. A serological analysis showed that the control group sharply decreased in albumin, Y-g1obu1in, and IgG so far as to cause dystrophy and to weaken antibody resistance but that ginseng extract and ginseng powder feeding groups, though in a little more restoring state than the control group, were still far from the normal group. The ADAPTAGEN feeding group restored to a state as comparable to the normal group in the contents of albumin ${\gamma}$-globulin, IgG and serum protein. In order words, it is noteworthy that ADAPTAGEN feeding was effective in revitalizing the destroyed cells of a living body and that it has the function of normalizing antibody components.

• Journal of Nutrition and Health
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• 제10권3호
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• pp.33-47
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• 1977

This study was devised to observe the nutritional effect by feeding of rice diet supplemented with Ginseng powder in Albino rats. The male albino rats (84 heads), weghing about 56g, were used for the experimental animals. They were divided into six diet groups; which were the 6.4% protein diet, the 12.8% protein diet and the 17.9% protein diet as the control and each control diet was supplemented with 3% of Korean Ginseng powder as experimental diet. These diet groups were again divided into 2 groups according to the feeding terms, 3 weeks and 6 weeks. The animals were sacrificed after feeding the coresponding diet for 3 weeks and 6 weeks and the liver, heart, kidney, intestine and serum were collected as samples for analysis. The growth rate, efficiencies of protein and food, lipid, cholesterol and nitrogen in the samples were determined. The results obtained are summerized as follows; 1. The growth rate were improved by feeding of the 13% and the 18% protein diet supplemented with 3% ginseng powder than the coresponding control diet group, although the same results were not observed in the 6.8% protein diet groups. 2. The consumptions of the food and the protein in each dietary group were similar to each other. 3. The efficiencies of the food and the protein were improved by feeding of the 13% and the 18% protein diet supplemented with the ginseng powder than each control diet group. 4. The lipid contents in the liver of each expperimental diet group, in the feeding for 3 weeks, were shown the tendency to increase slightly, compared with the coresponding control group, whereas in the feeding group for 6 weeks, the contents were shown rater the decreasing tendency. 5. The total cholesterol contents in the liver of each experimental diet group, in the feeding group for 3 weeks, were maintained slightly higher level than the coresponding control group, whereas in the feeding group for 6 weeks, the contents were shown similar levels. 6. The total cholesterol contents in the heart were maintained with similar level in each diet group and each feeding term.