• 한국정밀공학회지
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• 제12권11호
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• pp.27-35
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• 1995

The fluid coupling combined with a pump and a turbine have many merits compared with other couplings, their uses are increesing rapidly in various industrial fields at home and abroad in pursuit of high-speed more efficiency durability of various mechanic devices. The authorities concerned have recognized the improtance of the fluid coupling and supported its developement and now some trial products began to show up. As the structrue and characteristics of the fluid coupling have little similarity to other kinds of couplings and its fluid behavior is unique, so its characteristic analysis is expected to be difficult. Until now no satisfactory study on the characteristics of the fluid coupling seems to have been conducted at home, so a study on this field needs to be done urgently. The purpose of this research is to construct the experimental test set-ups and establish a series of performance test program for the domestically developed fluid couplings and to provide a software to store and utilize these experimental data which can be used to improve the performance of the fluid coupling and solve on the job problems confronted in operation. The performance test consists of taking measurment of torque, rpm and efficiency of the fluid coupling for three different amount of working fluid inside with various loads to the output shaft and finally infestigating the torque, rpm and efficiency characteristics of the fluid coupling with respect to these parameters. The results of this study can contribute valuable references to the development of variable speed fluid coupling and torque converter currently pursued by the domestic industry.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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• pp.264-268
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• 1996

Directional coupling optical switch which on the LiNbO$_3$ substrate is fabricated by using proton exchange method and self-aligned method. Proton exchange of proton diffusion method was applied to pattern a waveguide on LiNbO$_3$ substrate. The annealing at 400[$^{\circ}C$] was caroled out to control waveguide width and depth. The process of proton exchange was done at 150[$^{\circ}C$] for 120[min], 200[$^{\circ}C$] for 60[min] and annealing process was done at 400[$^{\circ}C$] for 90[min], 400[$^{\circ}C$] for 60[min]. The high speed directional coupling optical switch has very good figures of merits:the measured high frequency power were achieved.

• 마이크로전자및패키징학회지
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• 제20권4호
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• pp.69-74
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• 2013

In this paper, the impact of integrating large number of I/O (Input-Output) and Core power Delivery Network (PDN) on a 6 layers Flip-Chip Ball Grid Array (FCBGA) package is investigated. The impact of core induced supply noise on high-speed I/O interfaces, and high-speed I/O interface's supply noise coupling to adjacent high-speed I/O interfaces' jitter impact are studied. Concurrent stress validation software is used to induce SSO noise on each individual I/O interfaces; and at the same time; periodic noise is introduced from Core PDN into the I/O PDN domain. In order to have the maximum coupling impact, a prototype package is designed to merge the I/O and Core PDN as one while impact on jitter on each I/O interfaces are investigated. In order to understand the impact of the Core to I/O and I/O to I/O noise, the on-die noise measurements were measured and results were compared with the original PDN where each I/O and Core PDN are standalone and isolated are used as a benchmark.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권4호
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• pp.421-428
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• 2013

This paper describes analysis of journal bearings lubricated with ferrofluid, which are very suitable for high speed machines. Comparing to conventional lubricants, the coupling of hydrodynamic, thermal and magnetic properties of ferrofluid adds to the complexity in analysis. Modified Reynolds equation and energy equation are derived and solved numerically using finite volume method. Pressure distribution is got which takes temperature effect into consideration. Static characteristics are then discussed. One optimal scheme is also got according to analysis results.

• Journal of electromagnetic engineering and science
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• 제4권2호
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• pp.56-62
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• 2004

We present a multi-Gbit/s digital I/O interface based on RF-modulation and capacitive-coupling over an impedance matched transmission line. The RF-interconnect(RFI) can greatly reduce the digital switching noise and eliminate the dc power dissipation over the channel. It also enables reduced signal amplitude(as low as 200 ㎷) with enhanced data rate and affordable circuit overhead. This paper addresses the system advantages and implementation issues of RFI. A prototype on-chip RFI transceiver is implemented in 0.18-${\mu}{\textrm}{m}$ CMOS. It demonstrates a maximum data rate of 2.2 Gbit/s via 10.5-㎓ RF-modulation. The RFI can be very instrumental for future high-speed inter- and intra-ULSI data links.

• 소음진동
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• 제8권3호
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• pp.533-541
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• 1998

Recently, optical disk drives are increasingly demanded to have higher speed as well as high information density, especially for applications like CD ROM drives. To this end, improvement of their optical pickup structure and control is recognized the very challenging issue. In this paper, the pickup is first analytically modelled in a plane to describe its coupled auto-focusing and auto-tracking motions. Subsequently, the model is linearized and combined with actuator dynamics for the auto-focusing system. With its unmeasurable parameters being estimated based on experimental data, an approximate I-DOF linear model is obtained neglecting the coupling term. To design the high speed and robust positional servo controller realistic design specifications are addressed, and H control method is employed based on the approximate model. Finally, taking the pickup in a commerical high speed CD ROM drive as an example performance of the designed controller is verified through realtime experiments.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.155-158
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• 1999

In the high speed range for Vector control of Synchronous Reluctance Motor, the effect of iron loss and the cross-coupling of dq axis currents is dependent on the increase of the operating frequency can not be negligible. In this paper, we propose a decupling Vector control of dq axis current that the effect of iron loss is eliminated, and confirm that through simulation results.

• 전자공학회논문지
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• 제53권11호
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• pp.160-165
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• 2016

최근 광섬유를 이용한센서, 센서 시스템, 초고속 광통신에 의해 응용이 빠른 속도로 발전함으로서 이에 따라 광 결합기와 관련된 WDM소자의 수요가 급증해왔다. 본 연구에서는 국내최초로 Hopper type WDM(특허등록번호:10-1502954)을 설계 및 제작 하였다. 제작된 Hopper type WDM은 비대칭 버트 결합 광학계구조의 초고속 광통신용 쌍방향 $1{\times}3$ WDM 이다. 제작된 Hopper type WDM은 사용중심 파장이 각 각 850nm, 1300nm, 1550nm 이다. Hopper type WDM은 기존의 WDM이 지니고 있는 우수한 장점들을 지니고 있을 뿐만 아니라, 초고속 신호전송과 경제성이 우수하여 실용화에 큰 장점을 지니고 있다. 제작된 Hopper type WDM의 특성은 기존 $1{\times}3$ 광 커플러에 비하여 광 삽입손실이 평균 0.02~0.03dB정도 우수하다. 특히, 초고속 광 MUX 전송 시스템에 적용하여 실용화를 기대할 수 있고, 아울러 광섬유 센서 시스템 구성부품으로 응용되어 고감도 신호 검출 시스템으로 발전될 수 있다.

• 전자공학회논문지A
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• 제31A권6호
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• pp.88-97
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• 1994

We describe the design, fabrication, and performance of the optical fiber-photodiode 1$\times$12 arry module using mesa-type InS10.53T GaS10.47TAS/INP 1$\times$12 PIN photodiode array. We fabricated the PIN PD array for high-speed optical fiber parallel data link optimizing quantum efficiency, operating speed sensitivity from the PIN-FET structure, and electrical AC crosstalk. For each element of the array, the diameter of the photodetective area is 80 $\mu$m, the diameter of the p-metal pad is 90 $\mu$m, and the photodiode seperation is 250 $\mu$m to use Si v-groove. Ground conductor line is placed around diodes and p-metal pads are formed in zigzag to reduce Ac capacitance coupling between array elements. The dark current (IS1dT) is I nA and the capacitance(CS1pDT) is 0.9 pF at -5 V. No signifcant variations of IS1dT and CPD from element to element in the array were observed. We calulated the coupling efficiency for 10/125 SMF and 50/125 GI MMF, and measured the responsivity of the PD array at the wavelength is 1.55 $\mu$ m. Responsivities are 0.93 A/W for SMF and 0.96 A/W for MMF. The optical fiber-PD array module is useful in numerous high speed digital and analog photonic system applications.

• Structural Engineering and Mechanics
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• 제57권1호
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• pp.141-159
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• 2016

Bearing joint dynamic parameter identification is crucial in modeling the high speed spindles for machining centers used to predict the stability and natural frequencies of high speed spindles. In this paper, a hybrid method is proposed to identify the dynamic stiffness of bearing joint for the high speed spindles. The hybrid method refers to the analytical approach and experimental method. The support stiffness of spindle shaft can be obtained by adopting receptance coupling substructure analysis method, which consists of series connected bearing and joint stiffness. The bearing stiffness is calculated based on the Hertz contact theory. According to the proposed series stiffness equation, the stiffness of bearing joint can be separated from the composite stiffness. Then, one can obtain the bearing joint stiffness fitting formulas and its variation law under different preload. An experimental set-up with variable preload spindle is developed and the experiment is provided for the validation of presented bearing joint stiffness identification method. The results show that the bearing joint significantly cuts down the support stiffness of the spindles, which can seriously affects the dynamic characteristic of the high speed spindles.