• Composites Research
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• 제12권2호
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• pp.36-45
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• 1999

Since carbon fiber epoxy composite materials have excellent properties for structures due to their high specific strength, high modulus, high damping and low thermal expansion, the hollow shafts made of carbon fiber epoxy composites have been widely used for power transmission shafts for motor vehicles, spindles of machine tools and rollers for film manufacturing. However, the molded composite shafts are not usually accurate enough for mechanical machine elements, which require turning or grinding of composite hollow shafts. In this paper, the grinding characteristics of composite hollow shafts, which are flexible in the radial and circumferential directions, were investiaged experimentally and analytically with respect to the stacking angle, thickness and outer diameter.

• 한국식품저장유통학회지
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• 제21권2호
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• pp.181-186
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• 2014

본 연구에서는 활용도가 낮은 메밀껍질을 활용하고자 효소처리 및 습식분쇄에 따른 통메밀 분말의 품질특성을 조사하였다. 습식 분쇄 통메밀 분말의 입도 분석 결과 메밀쌀의 평균 입자크기는 74.84 ${\mu}m$로 통메밀 분말에 비하여 약 4~5배가량 큰 것으로 나타났으며 습식분쇄 90분 이후에 큰 차이가 없었다. 총 페놀성 화합물 및 총 플라보노이드 함량의 경우 메밀쌀에 비하여 통메밀 분말에서 모두 증가하였으며 분쇄가 진행될수록 조금씩 상승하였다. Rutin 함량 조사결과 메밀쌀 44.10 ppm에 습식분쇄가 진행될수록 함량이 상승하여 습식분쇄 90분에서 152.90 ppm까지 증가한 뒤 이후로는 큰 변화가 없었다. Quercetin의 경우 습식분쇄 시간에 따른 큰 함량변화는 없는 것으로 나타났다. 무기질 함량 조사결과 메밀쌀에 비하여 통메밀 분말에서 Ca, K 및 Mg의 함량이 높게 증가하였으며 Zn 및 Mn이 통메밀 분말에서 검출되었다. 유리아미노산은 통메밀 분말에서 총 유리아미노산 함량이 22.27 mg%로 증가하는 것으로 나타났으며 특히 glutamic acid는 14.58 mg%에서 30.45 mg%로 두 배 이상 증가하는 것으로 나타났다. 이상의 결과 통메밀 분말 제조를 위한 습식분쇄 시간은 90분이 적절하였으며 통메밀 분말의 경우 메밀껍질의 유효성분의 활용이 가능하였으며 습식분쇄과정을 통한 식감개선이 가능하여 차후 다양한 가공제품으로 활용이 기대된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.395-398
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• 1997

In the modem manufacturing system, to achieve the unmanned automation, the stability of accuracy is required through a long working period. The thermal deformation of precision machine is predominant in this long time stability. While grinding slender and long workpiece at cylindrical grinding machine, we support workpiece using steadies to prevent the vibration of workpiece. The thermal deformation of the machine by grinding and internal heat source cause processing errors, so the steadies for compensating the thermal deformation in real time are strongly needed. In order to compensate these thermal deformation and grinding processing errors, the device to determine the precise positioning having the stroke of 10.mu.m is necessary. This paper suggests design and make the device to determine the precise positioning using thermoelectric device, to investigate the control characteristics and presents the heat actuator will be very useful in machine tool.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.201-203
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• 1991

T. Kanal et al, were studied the superconducting properties in Bi system by mechanical grinding, in which the authors found that the samples ground degraded from the superconducting phases to nonsuperconducting phases. To obtain more information of the practical application in Bi system with high-Tc phase in this paper, these samples mechanically ground and the high-Tc phase properties of grinding powder samples were investigated.

• 한국기계가공학회지
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• 제12권3호
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• pp.76-80
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• 2013

This paper reports some experimental results on the machining performance of ground & non-ground milling inserts. Five kinds of milling inserts were manufactured without grinding process and one milling insert was manufactured with grinding process. Machining experiments were carried out to compare the performance of ground & non-ground inserts. This experimental result indicate that tool wear, cutting force and surface roughness of the each tool. From the result five milling inserts that have non-grinding process and one milling insret that have grinding process compared appear.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.322-325
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• 2000

In the previous report1), the grinding characteristics of quartz were investigated. In this paper, the grinding mechanisms of brittle materials including ceramics and quartz are modeled and a new parameter SDR(Surface roughness Direction Ratio) is proposed to characterize the grinding mechanisms of such materials. A set of experiments were performed to verify the effectiveness of the suggested parameter. The experimental results indicate that the plastic deformation is the dominant material removal mode at the grinding conditions which show the higher value of SDR. In the case of quartz, the material was removed by brittle fracture in a lower value of SDR and by plastic deformation in a higher value of it. SDR is not affected by wheel mesh size when brittle fracture occured. But in the plastic deformation case, SDR value increases with wheel mesh size.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.309-314
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• 2001

The balance of high speed spindle system with high precision rotation like grinding machine is very important. Traditionally, we use trial and error method to balance the spindle. It takes much time. So we are developing the automatic balancing equipment being used in the grinding machine. The balancing head we develop is wireless. It will be used high-speed grinding machine. We use influence coefficient method to control the automatic balancer. Experiments are based on automatic and manual balancing. We perform test of the vibration filter. It helps to remove noise. The filter and experiments with automatic balancing controller show that automatic balancing control can be successfully achieved with the quick response and good stability characteristics.

• 시멘트
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• 통권130호
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• pp.26-34
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• 1993

분쇄에 드는 비용을 줄이면서 제품의 성능을 올리기 위한 목적으로 몇 가지 분쇄조제에 대하여 실험을 실시하였다. Ethylene Glycol, Diethylene Glycol, Triethanolamine 등과 같은 통상적인 분쇄조제는 환경오염을 유발한다. 그러므로 이러한 유해성 첨가제의 사용을 줄일 수 있는 새로운 분쇄조제의 개발이 요청되고 있다. 본 연구에서는 유지공장에서 부산물로 생산되는 몇 가지 물질을 사용하여 제조한 분쇄조제로 실험을 실시하였다. 그 결과는 다음과 같다. (1) 각 분쇄조제는 입도분포, 비표면적 증가, 경제성을 고려하여 희석한 상태로 $0.03\%$ 사용하는 것이 효율적이다. (2) 분쇄조제 DEG, S-3 및 S-4를 첨가한 경우 Blaine 값 3,100$cm^2/g$에 도달하는 시간은 30분이 소요되므로 분쇄조제의 첨가는 효과가 있다. (3) 분쇄조제 S-3, S-4가 입도분포상 양호하고 분쇄효율은 S-3이 우수하다. (4) S-3>S-4>DEG순으로 시멘트 모르타르의 압축강도를 향상시킨다.

• 한국정밀공학회지
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• 제13권5호
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• pp.60-66
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• 1996

Precision of bearing race is very important to maintain the clearance between ball and inner race. In internal grinding of bearing race, its roundness is dependent on shoe wear, accuracy of jig, dressing method and grinding conditions. In this study, the characteristics of shoe wear and eccentricity of workpiece were investigated experimentally. When wear of fornt shoe wear reaches at 100.mu. m and that of rear shoe reaches at 114 .mu. m, eccentricity of inner race is increased to 1.4 .mu. m. Roundness of race is mainly related to wear of rear shoe and ring type shoe is recommended to improve roundness of race.

• 한국응용과학기술학회지
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• 제40권5호
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• pp.945-954
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• 2023

In this study, Sparassis crispa(cauliflower mushroom), which is rich in beta-glucan, was pulverized using ultrafine grinding technology for its potential utilization as a diverse food ingredient. The physical and antioxidant properties of cauliflower mushroom powder were evaluated at various grinding times. The results showed that as the grinding time of cauliflower mushroom increased, the average particle size significantly decreased (p<0.05). Additionally, the water-holding capacity, swelling capacity, and water solubility index of cauliflower mushroom increased significantly(p<0.05). Based on the analysis mentioned above, cauliflower mushroom prepared as a superfine powder for 5 minutes exhibited superior physical and chemical properties as well as antioxidant characteristics and is expected to be widely used in various foods.