• 한국축산시설환경학회지
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• 제1권1호
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• pp.65-75
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• 1995

This experiment was carried out to the effects of population density and C/N ratios of feed on the growth, reproductive effciency and cast producation of the earthworm(Eisenia foetida). The population densities of 50, 100, 150, 200 and 250 individuals of the earthworm fed with different C/N ratios of 25, 35, 45 and 55 cow manures were studied in rearing box($6,400cm^3$), and at the fertility stage during a period of 60 days. The results were summarized as follows; The survial rate(SR), increasing rate(IR), reproductive efficiency(RE) and cast production of the earthworms showed highest values in C/N ratio of 25. These results may indicate that C/N ratio of 25 is a very favourable feed for the growth of the earthworms. The survial rate(SR) indicated significant positive correlation with reproductive efficiency(RE) in different C/N ratios of feeds. The survial rate(SR) showed highest values in population densities of $50{\sim}100$ worms/$6,400cm^3(64.0{\sim}128.0cm^3/worm$). On the contrary, increasing rate(IR) tended to decreased with the increased population densities. The survival rate(SR) indicated significant negative correlation with reproductive efficiency(RE) in different population densities of the earthworms. The cast production estimated were $31.6mg{\sim}67.4mg/day/worm$ grown in optimum population densities($50{\sim}100\;worms/6,400cm^3$). The earthworm casting are an excellent soil conditioning material or organic fertilizer sources with a high chemical composition and their physical properties.

• 산업식품공학
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• 제13권4호
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• pp.269-274
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• 2009

습식분쇄의 최적조건을 얻고자 부형제 종류, 농도, 습식 분쇄시 rotor speed, bead size, feed rate, 분쇄회수를 달리하여 분쇄한 결과, 부형제로는 gum arabic을 사용하여 5%의 농도로 첨가할 때 가장 좋은 분쇄효과를 나타내었다. Rotor speed를 달리하여 습식분쇄한 결과, rotor speed가 증가할수록 좋은 결과를 나타내어 4,000 rpm에서 가장 우수한 것으로 나타났다. 원료와 직접 부딪혀 분쇄를 하게 되는 bead는 0.4 mm의 크기를 사용하였을 때 가장 작은 사이즈로 분쇄되는 것으로 나타났다. 분쇄가 이루어지는 chamber내에 원료를 공급하는 비율에 따른 결과에서는 40 L/h 의 속도로 공급했을 때 가장 작은 입도분포를 보였다. 분쇄회수에 따른 영향은 횟수에 따라서는 8회 이상으로 분쇄하였을때 0.6 $\mu$m이하의 입도분포가 90% 이상으로 나타나 10회를 분쇄하였을때 가장 좋은 효과를 나타내었다. 연속운전과 비연속운전의 비교에서는 연속운전이 더 효율적이었으며 부형제 종류에 따른 영향은 gum arabic을 첨가하여 분쇄하였을때 가장 우수한 결과를 나타내었다. 따라서 적절한 농도와 종류의 부형제 사용과 rotor speed, bead size, feed rate, 용매와의 혼합비의 최적공정을 수립한 습식 분쇄기술로 초미세액상칼슘의 제조가 가능하였고, 습식분쇄기술을 식품가공기술로 활용할 수 있는 가능성을 확보하였다.

• 한국기계가공학회지
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• 제21권4호
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• pp.23-30
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• 2022

Small-scale production is increasing, and the manufacturing industry is gradually changing into a smart manufacturing industry. Therefore, research on securing optimal cutting conditions for factors affecting machining precision during cutting is very important. Therefore, the purpose of this study is to After machining the inner diameter hole of SCM415 steel with a cermet tool on a CNC automatic lathe, the surface roughness, dimensional accuracy, and dimensional straightness are measured according to the feed rate to analyze the machining characteristics and suggest optimal cutting conditions. The test material was cut using a cermet tool for secondary cutting after a round bar with a diameter of 20 mm was mounted on a CNC automatic lathe. The cutting length was fixed at 0.5 mm, and the cutting speed was fixed at 3200 rpm. When the feed rate was changed to 0.05, 0.1, and 0.15 mm/rev, the respective surface roughness during the 15th test was measured. Consequently, The lower the feed rate, the better is the surface roughness. In addition, the optimum cutting conditions for SCM415 steel were observed to be the most ideal cutting conditions than the condition of 0.05 mm/rev at a cutting speed of 3,200 rpm and a feed rate of 0.1 mm/rev.

• Fisheries and Aquatic Sciences
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• 제12권4호
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• pp.311-316
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• 2009

A 10-week feeding trial with four dietary protein levels (22%, 32%, 42% and 52%) and two dietary lipid levels (8% and 17%) was conducted to investigate the optimum dietary protein and lipid levels for growth of long-nosed barbel fingerlings. Survival rate of fish was not affected by either the dietary protein or the dietary lipid level. Weight gain and feed efficiency were affected by the dietary protein level (P<0.01), but not by the lipid level, and increased with the dietary protein level at the both lipid levels. Weight gain and feed efficiency of fish fed the 52% protein diets with 8-17% dietary lipids were not significantly different from those of fish fed the 42% protein diets with 8-17% dietary lipids and 32% protein diet with 17% dietary lipid. Daily feed intake of fish was not affected by either dietary protein or dietary lipid level. Protein efficiency ratio and protein retention rate of fish fed the 32% protein diet with 17% dietary lipid were significantly higher than those of fish fed the 52% protein diets with 8-17% dietary lipids. Moisture content of fish fed the diets containing 8% lipid were higher than those of fish fed the diets containing 17% dietary lipid at each protein level. Crude lipid content of fish fed the diets containing 17% dietary lipid were higher than that of fish the fed the diet containing 8% dietary lipid at each protein level. The results of this study indicated that 32% protein and 17% lipid could be the optimum dietary level for growth of juvenile long-nosed barbel.

• 한국양식학회지
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• 제10권3호
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• pp.311-320
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• 1997

조피볼락 사육시 수온과 먹이공급량이 성장과 사료효율에 미치는 영향을 알기위하여 사육수온과 먹이공급량을 달리하여 사육실험을 한 결과는 다음과 같다. 사육수온 12, 15 및 $18^{\circ}C$에서 사육한 결과 $15^{\circ}C$ 실험구에서 일간사료섭취율 및 일간성장률은 3.64 및 1.66%로 다른 실험구에 비하여 높게나타났으나, 사료효율은 40.7-45.7%로 실험구간에 차이가 없었다. 먹이공급량을 어체중의 0.0-3.0% 범위로 하여 사육실험한 결과 사료효율은 절식구를 제외한 나머지 실험구에서는 41.1-57.2%의 범위로 유의차가 없었고, 일간성장률은 1.5-3.0%공급구에서는 0.79-0.86%의 범위로 차이가 없었다. 어체분석결과 육질부비율은 전실험구에서, 간중량지수, 장중량지수 및 비만도는 1.0-3.0% 공급구에서 차이가 없었다. 혈액성상 분석결과 TP 및 TG는 전실험구에서, GOT, GPT, TG, GL 및 Ht는 1.0-3.0% 공급구에서 차이가 없었다. 이상의 결과로부터 조피볼락 1년생은 육상수조양식시 사육수온은 15-18$^{\circ}C$에서, 먹이공급량은 포식량의 약 70-80%가 적당한 것으로 사료된다.

• Journal of Biosystems Engineering
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• 제21권2호
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• pp.182-190
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• 1996

A macerating technique which can apply to the mechanical production system of the agricultural by-product was developed to increase the utilization of agricultural waste and solve the shortage problem in the forage supply for the livestock production. The macerating method is to shred the agricultural by-product by the two rolls which rotate at different speeds each other. The testing macerator was built and the optimum operating conditions are suggested. Results of this research are as follows: 1. The increase of the base roll speed and speed ratio between two rolls shows the better shredding index but decrease the drying rate. The optimum conditions of the base roll speed and the speed ratio between two rolls for the rice straw are 1200 rpm and 1.7-2.0 respectively. 2. The macerated alfalfa was dried to the 15%(w.b.) within 3 hrs in a field at speed ratio of rolls, 2:1 and base roll speed, 1800rpm. 3. The milled surface and straight knurled surface for the macerating roll have same effect on the drying rate of material. Both rolls have self-cleaning functions during operation.

• 한국축산시설환경학회지
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• 제1권1호
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• pp.47-53
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• 1995

An efficient Treatment of animal wastewater is one of the hot issues for preventing the environmental pollution. It should be established the design parameter in order to purify the animal wastewater. A test is carried on in the pilot plant as a simplified activated sludge process. A vibration sieve separator is deviced to keep the pollution load constant by means of separation of solid matter. The BOD removal efficiency of the vibration sieve showed over 50%. As the test results, the BOD contents of the influent was in average of 3,000 mg/I and that of the effluent 85 mg/I. So, the BOD removal rate showed 97% in average. The SS-contents in the primary chamber was about 3,300 mg/I and that of effluent 92 mg/I. The SS removal efficiency showed 97%. The removal rate of total nitrogen and phosphore were in average of 82% respectively. Carrying out in winter season, it showed relatively good results; The design parameter approved in this test can be applied to the full-time farmers.

• 한국소음진동공학회논문집
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• 제14권12호
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• pp.1322-1329
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• 2004

End-milling has been used widely in industrial system because it is effective to a material manufacturing with various shapes. Recently the end-milling processing is needed the high-precise technique with good surface roughness and rapid time in precision machine part and electronic part. The optimum mechanical vibration of main spindle, surface roughness and cutting temperature have an effect on end-milling condition such as, cutting direction, revolution of spindle, feed rate and depth of cut, etc. Therefore, this study carried to decide the working condition for optimum mechanical vibration of main spindle, surface roughness and cutting temperature using design of experiments, ANOVA and characteristic function. From the results of experimentation, mechanical vibration has an effect on revolution of spindle, radial depth of cut, and axial depth of cut. The surface roughness has an effect on cutting direction, revolution of spindle and depth of cut. And then the optimum condition used design of experiments is upward cutting In cutting direction, 600 rpm in revolution of spindle, 240 mm/min in feed rate, 2 mm in axial depth of cut and 0.25 mm in radial depth of cut. By design of experiments and characteristic function, it is effectively represented shape characteristics of mechanical vibration, surface roughness and cutting temperature in end-milling.

• 한국생산제조학회지
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• 제7권3호
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• pp.99-103
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• 1998

The curved surface machined by plate end mill causes a excess non-cutting volume, in these cases ball end mill is used for the curved surfaces. This study is aimed to obtain the optimum cutting conditions of various cutting speed, table speed, tool diameter, radius of curvature roughness on the conditions of various cutting speed, tool diameter, radius of curvature when machining the curved surface using the ball end mill. After designing curve rates, obtaining NC data by CAD/CAM system through CC-Cartesian method and transferred the data through DNC system, we machined the specimens by the CNC machining center, The surface roughness of specimens was measured by surface roughness tester and CNC 3D coordinate measuring machine. The cutting condition were the same as follow velocity; 15, 20, 25 30m/min, feed rate;40, 60, 80, 100m/min and radius of curvature; 30,40,50,60mm, tool diameters; ø8, ø12, ø16, ø 20mm. Analizing the working results, we can acquire the optimum cutting condition of curved specimen at the cutting velocity of 20~25m/min and the feed rate of 80mm/min. As the same cutting condition the best surface roughness was showed at ø16mm of the tool diameter. But the tool diameter was smaller than ø8mm. we could improve for the surface roughness by controlling the cusp.

• Tribology and Lubricants
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• 제30권3호
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• pp.139-145
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• 2014

Nowadays, most micro-patterns are manufactured during flow line production. However, a conventional rotary chemical mechanical polishing (CMP) system has a limited throughput for the fabrication of large and flexible electronics. To overcome this problem, we propose a novel linear roll-CMP system for the planarization of large-area electronics. In this paper, we present a statistical analysis on the linear roll-CMP process of copper-clad laminate (CCL) to determine the impacts of process parameters on the material removal rate (MRR) and its non-uniformity (NU). In the linear roll-CMP process, process parameters such as the slurry flow rate, roll speed, table feed rate, and down force affect the MRR and NU. To determine the polishing characteristics of roll-CMP, we use Taguchi's orthogonal array L16 (44) for the experimental design and F-values obtained by the analysis of variance (ANOVA). We investigate the signal-to-noise (S/N) ratio to identify the prominent control parameters. The "higher is better" for the MRR and "lower is better" for the NU were selected for obtaining optimum CMP performance characteristics. The experimental and statistical results indicate that the down force and roll speed mainly affect the MRR and the down force and table feed rate determine the NU in the linear roll-CMP process. However, over 186.3 N of down force deteriorates the NU because of the bending of substrate. Roll speed has little relationship to the NU and the table feed rate does not impact on the MRR. This study provides information on the design parameter of roll-CMP machine and process optimization.