• 전력전자학회논문지
• /
• 제14권5호
• /
• pp.415-422
• /
• 2009

본 논문은 기존의 시스템에 비해 시스템의 전력회로 구조의 큰 변경 없이 밧데리와 같은 전력저장 장치 디바이스의 추가와 개선된 운용방법을 적용한 첨두부하 삭감효과를 갖는 계통연계형 태양광발전시스템(UIPV)을 제안하였다. 개선된 운용방법과 에너지 저장장치의 추가로 기존 시스템에 비해 PV-array 용량을 작게 설치하여도 첨두부하 삭감효과를 크게 할 수 있으며, 가격 및 설치공간 등의 면에서 평가하여 기존시스템보다 더 나아짐을 확인하였다.

• Tribology and Lubricants
• /
• 제26권6호
• /
• pp.329-335
• /
• 2010

Recently, the End-milling processing is needed the high-precise technique to get a good surface roughness and rapid time in manufacturing of precision machine parts and electronic parts. The optimum surface roughness has an effect on end-milling working condition such as, cutting direction, spindle speed, feed rate and depth of cut, and so on. It needs to form the correlation of working conditions and surface roughness. Therefore this study was carried out to presume of surface roughness on end-milling working condition of Al7075 by regression analysis. The results was shown that the coefficient of determination($R^2$) of regression equation had a fine reliability of 87.5% and nonlinear regression equation of surface rough was made by multiple regression analysis.

• Journal of Advanced Marine Engineering and Technology
• /
• 제25권5호
• /
• pp.1086-1090
• /
• 2001

In this paper, a method deciding the permissible gains of the P and PT controllers for a retarded process under stable condition is proposed. For analysis, the controlled process is assumed to be first-order system with time delay. At first, the adjustable parameter sets causing stability limit are obtained based on the frequency domain condition which makes the roots of the characteristic equation locate on the imaginary axis. And the cut-in frequency ${\omega}_p$ to bring the parameter set to P control from PI control is derived is derived in terms of L and $T_m$ then ${\omega}_p$ is used to compute the maximum gain with stable condition. The results indicate that the permissible controller gains can be described by a unique if parameters L and $T_m$ are know.

• 한국정밀공학회지
• /
• 제21권8호
• /
• pp.27-33
• /
• 2004

The ultra-precision cutting is a key technique for the manufacture of optical components such as aluminium mirrors, electroless nickel mirror, plastic mirror in a variety of advanced science and technology applications. The paper presents experimental results of ultra-precision diamond fuming of electroless nickel materials. In general, the cutting condition such as feed rate and depth of rut, have effect on the surface roughness in ultra-precision diamond turning. To obtain an optimal cutting condition, we studied the effect of the cutting speed. the tool length, the tool nose radius, the feed rate and depth of cut on the surface roughness. So, the relationship of the surface roughness and cutting condition has been clarified. From the experimental results, the machined surface roughnesses were obtained less than 1nm rms.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 1997년도 추계학술대회 논문집
• /
• pp.59-64
• /
• 1997

This paper investigates the relationship between cutting conditions and Acoustic Emission(AE) signals; AEavg, AErms, AEmode, as the base working to monitor the tool wear with in-process. For this purpose, cutting tests were conducted on a CNC lathe with comprehensive cutting conditions.. It is known that AEavg and AErms are proportionaly increased as the increasing of cutting velocity and depth of cut respectively. It is also known that AEmode among three kinds of AE signals may be applied for in-process monitoring to make the self diagnosis system because of its stability to the variation of cutting condition.

• Journal of Welding and Joining
• /
• 제23권1호
• /
• pp.86-93
• /
• 2005

Abrasive waterjet (AWJ) can provide a more effective means for precision of difficult -to-machining materials such as ceramics and titanium alloys. The present study is focused on the surface roughness of abrasive waterjet cut surfaces. This paper investigated theoretical and experimental surface characteristics associated with abrasive waterjet cutting of titanium alloy Gr2. It is shown that the proper variations of several cutting parameters such as waterjet cutting pressure, cutting speed and cutting depth improve the roughness and characteristics on specimen surfaces produced by AWJ cutting. From the experimental results by AWJ cutting of titanium alloy Gr2, the optimal cutting conditions to improve the surface roughness and precision were proposed and discussed.

• 한국군사과학기술학회지
• /
• 제4권2호
• /
• pp.243-248
• /
• 2001

The present work is described the design factors and separation mechanism of ridge-cut explosive bolt in order to optimize the stage separation characteristics. Characteristics of test samples would differ depend on the detonating devices, the shape and size of bolt body, the amount of loading explosives, and the confinment conditions of bolt. Based on the results from these experimental factors, it appears to optimal condition of ridge-cut explosive that the amount of loading explosive seems to be near 110mg of RDX, the height of loading explosive is 3.5mm, the thickness of bolt is 3.9mm, and the degree of ridge is approximately $120^{\circ}$

• 한국기계가공학회지
• /
• 제4권3호
• /
• pp.5-12
• /
• 2005

In wire discharge machining which is using STD 11 as die materials, the major factors of machining speed are discharge voltage, discharge current, and discharge time. All of the three factors give the effect. Increasing of the discharge pulse time gets groove width wider and it relatively increases surface roughness and clearance. If no load voltage is decreased, surface roughness is good but it decreases machining speed. If on time is increased, machining speed will get faster and clearance and offset value also get bigger.

• 소성∙가공
• /
• 제19권5호
• /
• pp.290-295
• /
• 2010

Shaving technology is one of the significant metal forming technologies which can make the smooth and fine sheared surface of products after shearing process. The sheared surface on the side wall of the cutting edge is very important because it functions as a basic surface for measuring the dimensions of product. Effective sheared surface after shaving can be influenced by several working variables such as shaving allowance, shaving clearance, type of material and profile of cutting edge. The influence of these variables on shaving characteristics was investigated in this study. A cut-off die to make the simplified gear-shaped products was manufactured. Three kinds of sheet metals (AL5052, SPCC and SAPH440) of 3mm thickness were firstly sheared and then shaved for four shaving allowances and three sharing clearances. It was shown through experiments that the optimum working condition to give the maximum effective sheared surface in shaving was found ; Shaving allowance is 0.2mm and Shaving clearance is 0.01mm.

• 원예과학기술지
• /
• 제30권1호
• /
• pp.13-20
• /
• 2012

본 연구는 스탠다드 국화 '백마' 품종의 플러그 묘 생산에 있어서 삽수의 조건이 지상부 생육과 발근 및 정식 후의 절화 생육에 미치는 영향을 알아보고자 실시하였다. 삽수에 잎을 많이 부착할수록 삽목묘의 지상부 생육이 양호하였고, 잎을 4-6장 부착하여 삽목하는 것이 다른 처리에 비해 발근에 효과적이었다. 삽수길이에 따른 삽목묘의 지상부 생육은 큰 차이가 없었으며, 삽수길이를 5-7cm로 처리하는 것이 발근상태가 양호하였다. 삽수 굵기는 3.1mm 처리에 비해 3.6mm와 4.2mm 처리에서 삽목묘의 지상부 생육과 발근이 양호하였다. NAA 처리농도가 높을수록 삽목묘의 지상부 생육이 억제되었으며, 뿌리의 길이도 짧아졌다. NAA $100mg{\cdot}L^{-1}$를 1시간 처리하여 삽목하는 것이 삽목묘의 지상부 생육과 발근에 효과적이었다. 피트모스와 펄라이트를 2:2로 혼합한 배지에서 다른 처리에 비해 뿌리의 길이, 수 및 무게 등이 뿌리의 생육이 양호하였다. 잎이 적은 것보다 4-6개 부착된 삽수의 삽목묘를 정식했을 때, 절화장이 길고, 무게가 무거웠으며, 엽수도 많았다. 삽수길이에 있어서 7-9cm 처리가 절화장, 절화무게, 설상화 수 등 전반적인 절화의 생육에 효과적이었다. 따라서 '백마' 플러그 묘 생산시 7cm 길이에 3.6mm 굵기의 4-6장의 잎을 부착한 삽수를 삽목하는 것이 삽목묘의 지상부 생육과 발근 및 정식 후의 절화 생육을 위해 바람직하였다.