• Journal of the Korean Magnetics Society
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• v.3 no.3
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• pp.208-214
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• 1993

In order to investigate the origin of an increase in the coercivity with the Ta addition to Co-Cr films, the perpendicular magnetic anisotropy of Co-Cr film and CoCrTa film was measured by a torque magnetometer and VSM. In Co-Cr binary alloy film, the uniaxial anisotropy increased with increasing Cr content. The perpendicular magnetic anisotropy of $Co_{81.7}Cr_{16.7}Ta_{1.6}$ film was larger than that of $Co_{81}Cr_{19}$ film, both of which were deposited at the same substrate temperature of $100^{\circ}C$. The change in the perpendicular magnetic anisotropy with annealing was studied to understand the Ta addition effect. The amount of decrease in perpendicular magnetic anisotropy of the CoCrTa film by the annealing was larger than that of Co-Cr film. And the perpendicular magnetic anisotripies of Co-Cr film and CoCrTa film after annealing were almost the same. The cause of this was interpretated as the enhanced segregation of solute atoms in the Ta added thin film in the as-deposited state. The enhanced segregation of solute atoms increases the perpendicular magnetic anisotropy of the film, and causes the increase of perpendicular coercivity of the film.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.818-829
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• 2003

A cooperating control algorithm for two nonholonomic mobile robots is proposed. The task is composed of collision avoidance against obstacles and carrying a ladder. The front robot and the rear robot are called the leader and the follower, respectively. Each robot has a nonholonomic constraint so it cannot move in perpendicular directions. The environment is initially supposed to be unknown except target position. The torque that drives leader is determined by distance between the leader and the target position or the distance between it and the obstacles. The torque by target is attractive and the torque by obstacles is repulsive. The two mobile robots are supposed to be connected by link that can be expanded and contracted. The follower computes its torque using position and orientation information from the leader by communication. Simulation results show that the robots can drive to target position without colliding into the obstacles and maintain the distance in the allowable range.

• Wind and Structures
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• v.5 no.5
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• pp.393-406
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• 2002

Aerodynamic pressures and forces were measured on a model of a solar panel containing six slender, parallel modules. Of particular importance to system design is the aerodynamically induced torque. The peak system torque was generally observed to occur at approach wind angles near the diagonals of the panel ($45^{\circ}$, $135^{\circ}$, $225^{\circ}$ and $315^{\circ}$) although large loads also occurred at $270^{\circ}$, where wind is in the plane of the panel, perpendicular to the individual modules. In this case, there was strong vortex shedding from the in-line modules, due to the observation that the module spacing was near the critical value for wake buffeting. The largest loads, however, occurred at a wind angle where there was limited vortex shedding ($330^{\circ}$). In this case, the bulk of the fluctuating torque came from turbulent velocity fluctuations, which acted in a quasi-steady sense, in the oncoming flow. A simple, quasi-steady, model for determining the peak system torque coefficient was developed.

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.2
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• pp.1-6
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• 2009

The APU(Auxiliary Power Unit) needs a set of complex pipeline for the fuel supply system where some of the main valves controlling the flow rate consist of the servo valve worked with a torque motor. The input electric current produces an induced magnetic field almost perpendicular to the background magnetic filed generated by fixed permanent magnets. The induced torque deforms the tubular bushing, and directly rotates an armature, which can open and close the valve. In this study, we start from a basic analytic model using a simple electro-magneto-statics, and expand our model to the three-dimensional one computationally applying a commercial code named COMSOL. The result is compared with each other, and reasonable numerical data are obtained for the dynamic behavior and multi-physics system.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.361-364
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• 2002

This paper discusses the influencing factors such as coring position, height to diameter ratio of core specimen(h/d) and coring torque on the strength estimation of concrete by small site coring method in order to verify the validities of small size core method. According to results, as for the influence of drilling position, when core specimens are obtained from the place parallel to placing direction, compressive strength of core specimens are higher than those perpendicular to placing direction. This is due to the loss of the area of core specimen perpendicular to plating direction by bleeding. And in case of $\phi$ 24mm core specimen, when vertical drilling against placing direction is taken. compressive strength of core specimen obtained at the bottom of the structure is higher than that at the top of the structure. As for the influence of height to depth ratio, as h/d ratio increases compressive strength shows to be decreased. As for the influences of rotation speed of drilling machine, as its speed goes up, compressive strength decreases, regardless of core diameter.

• Journal of Biosystems Engineering
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• v.19 no.3
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• pp.175-184
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• 1994

This study was conducted to investigate experimentally the basic characteristics of the torque of the cutterbar driving shaft as the double-knife was used instead of the conventional standard single-knife type. A new design for inclined setting of the cutterbar relative to the direction perpendicular to combine harvester movement was investigated to test a possible reduction of concentrated load caused by the simultaneous cutting of many rows. It was evaluated that the maximum torque and mean total power of the driving shaft due to the cutting resistance of the rice straw were largely depended upon the rotational shaft-speed and straw feeding rate, but were resepectively 1.1~2.3 and 1.15~1.34 times higher compared to those while idling. It was also proved that the inclined setting of the cutterbar could save a considerable amount of energy required for its driving shaft.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.211.1-211.1
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• 2007

• Proceedings of the Korean Magnestics Society Conference
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• 2009.12a
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• pp.62-62
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• 2009

• Journal of the Korean Magnetics Society
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• v.26 no.6
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• pp.179-184
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• 2016

For an industrial spin-transfer torque (STT) MRAM, low switching current and high thermal stability are required, simultaneously. For this point of view, it is essential to find magnetic materials which satisfy high spin polarization and strong perpendicular magnetocrystalline anisotropy (MCA). In this paper, we investigate electronic structures and MCA energies of perovskite $CoFeX_3$ (X = O, F, S, Cl). For X = F and Cl, spin polarization at the Fermi level are 97 % and 96 %, respectively, which are close to a half metal. Furthermore, Co-terminated 5-monolayer (ML) $CoFeX_3$ (X = O, F, S, Cl) films show perpendicular MCA. In particular, the MCA energy of the Co-terminated $CoFeCl_3$ is about 1.0 meV/cell which is three times larger than that of a 5-ML CoFe film. Therefore, we expect to realize a magnetic material with high spin polarization and strong perpendicular MCA energy by utilizing group 6 and 7 elements in the periodic table, and to contribute to commercializing of the STT-MRAM.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.17 no.1
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• pp.23-32
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• 2021

Conventional wind power generators have limited installation sites due to low efficiency due to reverse resistance or high cut-in speed. To compensate for these problems, this study proposed another new type of tilting wind turbine. The key to this method is the structural design of a cylindrical cam with a guide groove that allows the blade to tilt. As the blade rotates by the cam, it tilts according to the angle. In the section that generates torque by receiving drag, the blade is made perpendicular to the wind. And it is a structure that creates a parallel state with the wind in the section where reverse resistance occurs. We prepared six types of cams considering the length of the section subject to drag, reverse resistance, tilting section. The performance was analyzed as the maximum value of the output, torque coefficient, and efficiency coefficient, which is indicated by setting different wind speed and low TSR.