• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.21 no.7
• /
• pp.1013-1020
• /
• 1997

Among various gyroscopes, the vibrating gyroscope has advantages such as compact size, mass-productivity and low cost. However this kind of gyroscope usually suffer from low linearity and low signal to noise ratio. Therefore, it is necessary to study on vibrating gyroscope to improve performance. In this paper, triangular cross section si selected in consideration for several points. The existing designs of exciting and sensing have some problems such that small signal size and low linearity. This paper proposes new design of exciting and sensing which is named one period exciting and the other period sensing. This design improves signal size, but it cannot improve linearity. This is because above two designs are the same open-loop type. So, another new design is proposed, which is named rebalancing, is applied to one period exciting and the other period sensing. This design are closed-loop type. It feedbacks the output signal. According to control theory, it can improve linearity. The circuits of each design are realized and used to calibration test. Calibration results show that new design of rebalancing improves linearity and signal size.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.1052-1057
• /
• 2004

A small-scale loop heat pipe with polypropylene wick was fabricated and tested for its thermal performance. The container and tubing of the system was made of stainless steel and several working fluids were used to see the difference in performance including methanol, ethanol, acetone, R134a, and water. The heating area was 35 mm ${\times}$ 35 mm and there were nine axial grooves in the evaporator to provide a vapor passage. The pore size of the polypropylene wick inside the evaporator was varied from 0.5 m to 25 m. The size of condenser was 40 mm (W) ${\times}$ 50 mm (L) in which ten coolant paths were provided. The inner diameter of liquid and vapor transport lines were 2.0 mm and 4.0 mm, respectively and the length of which were 0.5 m. The PP wick LHP was operated with methanol, acetone, and ethanol normally. R134a was not compatible with PP wick and water was unsuitable within operating limit of $100^{\circ}C$. The minimum thermal load of 10 W (0.8 W/cm2) and maximum thermal load of 80 W (6.5 W/cm2) were achieved using methanol as working fluid with the condenser temperature of $20^{\circ}C$ with horizontal position.

• Journal of Mechanical Science and Technology
• /
• v.19 no.4
• /
• pp.1052-1061
• /
• 2005

A small-scale loop heat pipe (LHP) with polypropylene wick was fabricated and tested for investigation of its thermal performance. The container and tubing of the system were made of stainless steel and several working fluids were tested including methanol, ethanol, and acetone. The heating area was $35\;mm\;{\times}\;35\;mm$ and nine axial grooves were provided in the evaporator to provide vapor passages. The pore size of the polypropylene wick inside the evaporator was varied from $0.5\; {\mu}m\;to\;25\;{\mu}m.$ The inner diameter of liquid and vapor transport lines were 2.0 mm and 4.0 mm, respectively and the length of which were 0.5 m. The size of condenser was $40\;mm\;(W)\;{\times}\;50\;mm\;(L)$ in which ten coolant paths were provided. Start-up characteristics as well as steady-state performance was analyzed and discussed. The minimum thermal load of $10\;W\;(0.8\;W\;/cm^{2})$ and maximum thermal load of $80\;W\;(6.5\;W\;/cm^{2})$ were achieved using methanol as working fluid with the condenser temperature of $20^{\circ}C$ with horizontal position.

• Journal of Energy Engineering
• /
• v.18 no.4
• /
• pp.258-263
• /
• 2009

Jet Loop Reactor(JLR), in which a two-phase nozzle is installed, is the new design technique for the treatment of high concentration wastewater by accelerating of oxygen contacting between substrate and surrounding bacteria. This numerical study of the two phase jet flow was conducted to find the optimum design of JLR. It was shown that there was a minimum velocity in the nozzle for continuous circulation of wastewater. The optimum location and the size of the draft tube for continuous circulation were examined. It was certain that the smaller the air size is, the more the effect of the mixing increases. The relation between the mixing effect and the turbulence was confirmed.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.963-966
• /
• 1998

In this paper, a fingerprint classification algorithm is presented. Fingerprint types are classified into five categories: arch, tented arch, left loop, right loop and whorl. Singular points (cores and deltas) are detected using Poincare index on the directional image smoothed by adaptive window size. The method is shown to be robust to the variation of fingerprint image qualaity.

• Journal of information and communication convergence engineering
• /
• v.9 no.3
• /
• pp.256-259
• /
• 2011

In this article, new microstrip slow-wave bandpass filters using open loop resonator loaded with inter-digital capacitive fingers is proposed. The filter features not only compact in size, but also exhibits spurious stop-band rejection. Filters of this type with elliptic function and Chebyshev response are demonstrated. There is good agreement between experimental and full-wave electromagnetic (EM) simulation results.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 1999.11a
• /
• pp.31-34
• /
• 1999

기-고체간의 접촉효율이 높고, 층 내 전체에 걸쳐서 균일한 기-고의 접촉을 갖는 등 많은 장점이 있어 석탄연소로, 촉매반응기와 같은 여러 기-고 반응기에 적용이 확대되고 있는 순환유동층은 높은 유속에서 조업되므로 상승관내 고체입자들은 즉시 비산하게 된다. 따라서, 원활한 반응에 필요한 상승관내 적절한 고체체류량 유지를 위해 고체입자들 대부분은 싸이클론에서 포집 되어 고체재순환부에 의하여 상승관내로 재주입 된다.(중략)

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.5
• /
• pp.501-505
• /
• 2008

In this paper, we present a multi-turn circular loop antenna for portable terrestrial DMB. In order to satisfy the two contradictory requirements of small antenna size and high receiving capability, the proposed antenna's diameter and turns are fixed to be 4 mm and 80 turns, respectively and its quality factor $\mathcal{Q}$ is set 1 in order to have high transfer function. The fabricated antenna length is 30 mm as small and its measured gain is -15 dBd. The antenna receiving power is verified by measurement very comparable with the receiving power of a commercial terrestrial DMB monopole antenna of length 190 mm.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.10
• /
• pp.1845-1851
• /
• 2016

In this paper, a design method for a wideband square loop antenna for Digital TV applications is studied. The proposed loop antenna is a square loop antenna combined with circular sectors to connect with central feed points. The square loop is used instead of the circular loop in order to miniaturize the antenna size. The input reflection coefficient and gain characteristics of the proposed antenna are analyzed to match with the 75 ohm port impedance for DTV applications. The effects of the gap between the circular sectors and the length of the square loop on the input reflection coefficient and gain characteristics are examined to obtain the optimal design parameters. The optimized antenna is fabricated on an FR4 substrate, and the experiment results show that it operates in the frequency band of 470-1,300 MHz for a VSWR < 2, which assures the operation in the DTV band.

• Journal of Veterinary Clinics
• /
• v.39 no.4
• /
• pp.149-155
• /
• 2022

The aim of this study was to compare the mechanical properties of 0.6 and 0.8 mm cerclage wires with the 1.0 mm cerclage wire in the twist, single-loop, double-loop, double-wrap, and loop/twist knot methods. Six stainless steel cerclage wires of various diameters in different knot methods were tied round a customized jig mounted on a load testing machine. The initial tension, initial stiffness, and yield load were evaluated. The failure mode of each cerclage was observed. For each wire size, the double-loop, double-wrap, and loop/twist knots showed significantly greater initial stiffness, and yield load than those seen with twist and single-loop knots. The single-loop knot showed the least initial stiffness regardless of the diameter. As the cerclage wire diameter increased, the cerclage tended to show significantly greater initial stiffness, and yield load. Failure modes varied depending on the knot configurations. Single-loop knots of smaller-diameter wires less than 1 mm had similar or lower initial tension, initial stiffness, and yield load than a twist knot. Owing to the variance in mechanical properties, the clinical application of the knot type should depend on the diameter of the cerclage wire.