• 한국수산과학회지
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• 제1권2호
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• pp.121-127
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• 1968

This research has been dealt with the nutritional component analysis of two kinds of non-edible marine algae, Sargassum herneri (Turner) C. Ag. and Zostera marina Linne which grow abundantly around the southern coast of Korea, These marine algae were mixed in several kinds of samples rates with the combined feed for poultry sold in the market. These were given to 35 chicken in seven test divisions respectively. We have experimented with 35 chicken grown up for two weeks after hatchout. The combined food for poultry obtained from the market was set up as control divisions. The experiments were as follows: 1) The average weight increase in each test division during feeding (Table 5, Fig.2). 2) Food conversion rate and food efficiency in each test division (Table 7). 3) The comparison of digestive rate of crude protein during feeding (Table 8), The results were as follows: 1) The weight increasing rate of the test animal stock fed the food containing $5\~10\%$ of Sargassum horneri (Turner) C. Ag. powder was higher than the rate of those fed only market food for poultry. 2) The stock given food containing $10\%$ Zostera marine powder showed lower growth than the control divison. 3) No apparent trouble owing to salt component involved in the marine algae was found. 4) The stock given food containing sodium glutaminate and Sargassum horneri (Turner) C. Ag. had better result than that without sodium glutaminate.

• 동력기계공학회지
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• 제18권5호
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• pp.94-99
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• 2014

In this study, AISI M2 powder was selected primarily through various literature in order to improve the hardness and wear resistance. Among the laser metal deposition parameters, laser power was studied to improve the deposition efficiency in the laser metal deposition using a diode pumped disk laser. SKD61 hot work steel plate and AISI M2 powder were used as a substrate and powder for laser metal deposition, respectively. Fixed parameters are CTWD, focal position, travel speed, powder feed rate, etc. Experiments for the laser metal deposition were carried out by changing laser power. Through optical micrographs analysis of cross-section in LMD track, effect of the major parameters were predicted by track pitch. As the track pitch increased, so the reheated zone width, the overlap width and the minimum thickness was decreased. The hardness was decreased in the HAZ area, the hardness in the reheated HAZ area was decreased significantly and regularly in particular.

• Asian-Australasian Journal of Animal Sciences
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• 제18권12호
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• pp.1769-1774
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• 2005

This experiment was carried out to evaluate the effects of feeding green tea powder on laying performance and egg quality in hens. A total 180 'Tetran Brown' laying hens aged 40 weeks were assigned to 6 treatments in a completely randomized design. Each treatment consisted of five replicates accommodating six layers per replication. The experimental diets were a negative control containing no green tea, a positive control diet containing antibiotics (0.05% chlortetracycline) and diets containing 0.5%, 1.0%, 1.5% and 2.0% green tea powder. Egg production rate of layers fed the diets containing green tea powder did not differ significantly from that of the negative and positive controls (p>0.05). Egg weight was decreased significantly in the group fed the diet containing 0.5% green tea powder (p<0.05). Feed intake of layers was significantly higher for the diet containing 1.5% green tea powder compared to that of negative and positive control diets (p<0.05). The eggshell thickness reduced significantly in the layer group fed the diets containing green tea powder regardless of dietary levels (p<0.05). Green tea powder tended to reduce egg yolk cholesterol in this experiment. Particularly, dietary 2% level of green tea powder significantly suppressed the cholesterol contents of the egg yolk (p<0.05). Thiobarbituric acid value (TBA) of egg yolk was significantly reduced by green tea diets (p<0.05). The yellowness of egg yolk was increased in the layers fed the 2.0% green tea diet compared with that of control diet (p<0.005). The Linoleic and $\alpha$-linolenic acids tended to increase in the group fed diets containing 1.5% green tea powder even though there were no significant differences among treatments (p>0.05). The oleic and docosahexaenoic acid contents of the egg yolk were similar among treatments (p>0.05). Based on the results of the experiment, it is concluded that green tea powder inclusion in the diet for layers at 2.0% level can reduce the cholesterol content and TBA value of the egg yolk, implying its potential effect on egg quality parameters.

• 한국수산과학회지
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• 제50권4호
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• pp.366-371
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• 2017

Six experimental diets for juvenile sea cucumbers Apostichopus japonicus were evaluated and compared with current commercial diets. Sea cucumbers (50 per tank; initial mean weight $2.3{\pm}0.1g$) in three replicates of seven groups were fed one of six experimental diets (ED1, 20% wild-harvested Sargassum thunbergii powder; ED2, 20% commercial S. thunbergii powder; ED3, 20% Undaria pinnatifida and Ascophyllum nodosum powders; ED4, 40% U. pinnatifida and A. nodosum powders; ED5, 10% brewer's yeast; and ED6, 10% sea shell powder) or a commercial diet (CD) for 28 weeks. The survival rate in all groups was 85-94%, with no significant difference among the experimental groups. The mean body weight of the sea cucumbers was significantly different among the experimental groups 6 weeks after the feeding trial. The final mean weight of the sea cucumbers was highest in ED1, ED3, and ED4, followed by ED6, ED5, ED2, and CD, in decreasing order. The results of this study suggest that U. pinnatifida and A. nodosum powders could provide a substitute for the S. thunbergii powder commonly used in commercial sea cucumber diets. Thus, the EP4 diet formulation, which contains no S. thunbergii, could be used as a practical feed for juvenile sea cucumbers.

• 한국세라믹학회지
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• 제29권10호
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• pp.822-826
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• 1992

SiO2 doped sapphire single crystals were grown by Verneuil method using feed material which prepared by adding SiO2 in Al2O3. Crystal growing were attempted with varing doping amount of SiO2 from 0.01 to 1.0 wt% and when the doping amount of SiO2 were 0.01~0.04 wt%, single crystals could be attained. Starting materials for feed powder were 99.99% purity alumina and extra pure SiO2 powder. Mixing these two materials by wet milling for 24 hours and drying the mixture and then was calcined at 900~110$0^{\circ}C$ for 2~4 hours. The grown crystals had yellowish color and were somewhat transparent. During growing process the flow range of oxygen was 5~7.5ι/min and of hydrogen was 13~25ι/min, the average growth rate was 7.0~11 mm/hr. The pressure of gases were fixed at 5psi. The color of crystal was appeared and mechanical property of sapphire was developed by doping of SiO2.

• 한국산학기술학회논문지
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• 제17권4호
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• pp.448-453
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• 2016

선박의 프로펠러나 임펠러와 같은 유체기기에서는 캐비테이션 현상으로 인해 마모와 침식이 발생한다. 이와 같은 기기손상은 소음과 진동을 발생시켜 기기수명을 단축시키는 문제점을 가지고 있다. 본 연구에서는 캐비테이션 현상에 대한 저항성을 높이기 위해 산업 현장에서 많이 사용되고 있는 고속화염용사코팅의 공정 최적화에 따른 각 요소별 중요도를 분석하였다. 다구찌 실험계획법을 적용하여 ALBC3 모재 표면에 비정질 분말을 코팅하였고 기공도 실험을 통해 각 요소별 특성을 분석하였다. 다구찌 실험계획법에 의해 고속 화염용사(HVOF) 코팅의 최적 공정을 찾아낸 결과 연소압이 80 psi, 코팅거리가 270 mm, 이송속도가 200 mm/s, 분말속도는 25 g/min으로 확인되었고, 그 결과, 연소압, 코팅거리 및 분말속도는 25% 이상으로 비슷한 기여도를 나타냈고 이송속도는 19%로 다소 떨어지는 수준을 나타내었다. 공정에 대한 각 인자별 기여도는 약간의 차이는 있지만 그 차이가 크지 않으므로 네 개의 인자 모두 고속 화염용사(HVOF) 코팅 공정에서 중요한 기여를 하였다.

• Fisheries and Aquatic Sciences
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• 제11권4호
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• pp.190-194
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• 2008

We estimated the digestibility and growth rate of juvenile olive flounder (Paralichthys olivaceus) on three diets: raw fish-based moist pellets, moist pellets, and extruded pellets. The diets were created using commercially available methods, and a basic formulated powder. A reference diet was used to compare feed digestibility and the fish growth rate achieved using the experimental diets. The apparent digestibility coefficients (ADCs) of protein for raw fish-based moist pellets and moist pellets were significantly higher (P<0.05) than those for extruded pellets and the reference diet. The ADCs of nitrogen-free extracts (NFE) of extruded pellets and moist pellets were significantly higher (P<0.05) than those for raw fish-based moist pellets and the reference diet. Fish that were fed with the raw fish-based moist pellets showed the greatest weight gain (452.4%), which was not significantly different from that of fish fed with extruded pellets (414.4%; P>0.05). These results indicate that the higher protein efficiency in fish fed with extruded pellets can result in good growth performance within flounder culture systems.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.241-244
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• 2002

Deburring is conducted using MAF(magnetic abrasive finishing) method. Magnetic inductor is designed and manufactured to generate proper magnetic induction far deburring the burr formed in drilling SM45C. Rotational speed, table feed rate, grain size of powder and working gap are changed to investigate the effect on deburring.

• 한국분말재료학회지
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• 제25권3호
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• pp.220-225
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• 2018

The microstructure and mechanical characteristics of SUS630 specimens fabricated using the direct energy deposition (DED) process are investigated. In DED, several process parameters such as laser scan speed, chamber gas flow, powder carrier gas flow, and powder feed rate are kept fixed; the laser power is changed as 150 W, 180 W, and 210 W. As the laser power increases, the surface becomes smooth, the thickness uniformity improves, and the size and number of pores decreases. With the increase in laser power, the hardness deviation decreases and the average hardness increases. The microstructure of the material is columnar; pores are formed preferentially along the columnar interface. The lath-martensite phase governs the overall microstructure. The volumetric fraction of the retained austenite phase is measured to increase with the increase of laser input power.

• 한국기계가공학회지
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• 제19권10호
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• pp.81-86
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• 2020

A ceramic vacuum chamber feedthrough ceramic insulator is made of Al2O3; the manufacturing process involves filling alumina powder into a urethane mold and pressing it with a rubber press to produce a molded body. Thereafter, manufacturing is completed through primary shape processing, sintering, and secondary shape processing in the green body, which is a pressurized molding body, This work is intended to prevent defects in the first shape processing by improving the ceramic insulator in the green body, and to improve the productivity of the ceramic insulator by determining the optimal processing conditions.