• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 추계학술대회논문집
• /
• pp.428-433
• /
• 2006

This paper presents a new type of jetting dispenser for the integrated circuit(IC) fabrication and surface mount technology. The proposed system is featured by the piezoelectric actuator and hydraulic magnification device. After describing structural component of the dispensing mechanism and its operation principle, both the fluid modeling and the hydraulic magnification modeling are undertaken with a lumped-parameter method based on the analogy of the fluid system and mechanical system. A mathematical governing equation is then derived by integrating the fluid model with the mechanical model of the driving piston and piezoelectric actuator. Subsequently, in order to achieve a desired dispensing amount, control algorithm adjusting duty cycle of the driving voltage is synthesized and control responses are presented in time domain.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
• /
• pp.201-204
• /
• 2008

Based on the device physics, a new I-V equation for TFTs is derived and a simple parameter extraction method is suggested. The new method gives more physically meaningful threshold voltage and mobility, and the obtained values can be directly used for the TFT device modeling.

• 반도체디스플레이기술학회지
• /
• 제8권4호
• /
• pp.7-13
• /
• 2009

The slender device(long length and thin width) manufactured by stereolithography process suffers from large curl distortion. This paper adapts two control parameters such as a critical exposure and a penetration depth. The measurement of the test parts dimension are carried out by reverse engineering method with the optical 3-dimensional measurement equipment. We investigate how each parameter contributes to the part accuracy and estimates the optimal set of parameters which minimizes the dimensional error of the test parts. Finally, As being an the RAM slot as being an example of the slender device, the RAM slot is made with the optimal values of control parameter and the results are investigated

• KIEE International Transactions on Electrophysics and Applications
• /
• 제5C권1호
• /
• pp.14-17
• /
• 2005

In this paper, an automated methodology for generating model parameters considering real manufacturing processes is presented with verified results. In addition, the outcomes of applications to the next generation of flash memory devices using the parameters calibrated from the process specification decision are analyzed. The test vehicle is replaced with a well-calibrated TCAD simulation. First, the calibration methodology is introduced and tested for a flash memory device. The calibration errors are less than 5% of a full chip operation, which is acceptable to designers. The results of the calibration are then used to predict the I-V curves and the model parameters of various transistors for the design of flash devices.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제11권4호
• /
• pp.272-277
• /
• 2011

The ambipolar behavior of tunneling field-effect transistors (TFETs) has been investigated quantitatively by introducing a novel parameter: ambipolarity factor (${\nu}$). It has been found that the malfunction of TFET can result from the ambipolar state which is not on- or off- state. Therefore, the effect of ambipolar behavior on the device performance should be parameterized quantitatively, and this has been successfully evaluated as a function of device structure, gate oxide thickness, supply voltage, drain doping concentration and body doping concentration by using ${\nu}$.

• 한국자기학회지
• /
• 제13권5호
• /
• pp.216-220
• /
• 2003

본 연구에서는 MRAM(magnetic random access memory)이 10 GHz까지 높은 주파수에서 동작할 때 쓰기 신호와 읽기 신호가 얼마나 효율적으로 전달되는지 계산하였다. 이를 위해 읽기와 쓰기에 필요한 도선이 있는 시편을 3차원으로 모델링하였다. 모의실험은 쓰기 동작과 읽기 동작으로 나눠서 수행되었고, FEM(finite element method) 알고리즘을 이용하여 S-parameter를 출력하였다. 계산된 결과를 이용하여 실험적으로 설계된 MRAM 시편의 쓰기와 읽기 동작에서 전송계수 S$_{21}$을 각각 DC에서 1 GHz 그리고 100 GHz 까지의 영역에서 해석하였다. 또한 각각의 길이가 600 $\mu$m인 bit line과 sense line사이의 절연체 두께를 500에서 1500$\AA$으로 변화시켰을 때, 3 dB 감쇄 주파수를 135에서 430 MHz까지 약 3.3배 높일 수 있었다. 그리고 계산된 S-parameter를 이용하여 전달 지연을 계산하여 접근시간을 예측하였다.

• 드라이브 ㆍ 컨트롤
• /
• 제12권4호
• /
• pp.54-59
• /
• 2015

Due to the tendency to use high speed pneumatic cylinders to improve productivity, cushioning devices are adopted to decelerate the piston motion of pneumatic cylinders to reduce noise, vibration, and impact. This paper presents a comparison of the cushion characteristics of a high speed pneumatic cylinder with a relief valve type cushioning device. The system parameters selected are the damping coefficient, Coulomb friction, heat transfer coefficient, and cracking pressure of the relief valve in the air cushioning device. The integral of the time multiplied square error (ITSE) is used to quantitative measure the cushioning performance to assess the effect of varying these. The cushioning performance achieved good results when the ITSE is a minimum value. In a comparison of the piston displacement and velocity with the variations in system parameters, the heat transfer coefficients are not as significantly affected as the other. Also, the cracking pressure of the relief valve is mainly affected by the pressure and temperature in the cushion chamber.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집C
• /
• pp.445-450
• /
• 2001

DVD(Digital Versatile Disk) is the data storage media devised to make high storage density and high data input/output possible. Therefore higher rotational speed and better accuracy in optical pick-up are required compared with the existing optical storage device. These operational functional requirements are concerned with abilities of optical storage device. Especially, High rotational speed is deeply concerned with the noise and vibration of optical storage device, is important problem in development of optical storage device so much. This paper propose a new concept ROM media of optical storage device named as Cylindrical ROM media, and evaluate this by means of Axiomatic approach and empirical data.

• 한국정밀공학회지
• /
• 제28권1호
• /
• pp.89-95
• /
• 2011

High stiffness frame design for a spine manipulation device was developed in this research. For the safety of a spinal manipulation, high stiffness of the device is required. A finite element (FE) model of the device frame is created and validated by measured vibration data. Parameters are suggested for high stiffness design of the frame. Based on the Taguchi design of experiment (DOE), a practical set of design parameter values is suggested.

• Structural Engineering and Mechanics
• /
• 제53권5호
• /
• pp.1031-1049
• /
• 2015

This paper highlights the role of innovative vibration control system based on two promising properties in a parallel configuration. Hybrid device consists of two main components; recentering wires of shape memory alloy (SMA) and steel pipe section as an energy dissipater element. This approach concentrates damage in the steel pipe and prevents the main structural members from yielding. By regulation of the main adjustable design parameter, an optimum performance of the device is obtained. The effectiveness of the device in passive control of structures is evaluated through nonlinear time history analyses of a five-story steel frame with and without the hybrid device. Comparing the results proves that the hybrid device has a considerable potential to mitigate the residual drift ratio, peak absolute acceleration and peak interstory drift of the structure.