• Applied Microscopy
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• 제13권1호
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• pp.49-61
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• 1983

Protoplast releasing mechanisms from Trichoderma koningii, fine structures of the released protoplsts, and their regeneration mode were studied by scanning and transmission electron microscopy. Two types of protoplast releasing mechanisms were observed. In one mechanism, cytoplasm emerged through a cell wall pore developed by cell lytic enzymes and formed a spherical protoplast. In the other mechanism, as the cell wall became progressively thinner, the inner cytoplasm partially rounded to form nonspherical bodies which became spherical protoplasts after being released into the enzyme solution. But, these two types of protoplast releasing mechanisms did not seem to be. mutually exclusive but could occur on the same mycelium simultaneously. And it appeared that cytoplasm which did not become a protoplast by the first mechanism could from a protoplast by the second mechanism. The preparations contained two types of protoplasts, released from different sites of the mycelia. Those released from younger mycelia had dense cytoplasm and small vesicles. Those released from the older mycelia had less dense cytoplasm and larger vacuoles. In the case of regeneration, before producing normal mycelia, most of the protoplasts assumed aberrant tube and yeast-like-forms. Normal mycelia were produced at the end of the yeastlike-forms and sometimes in the middle of the aberrant tube.

• 로봇학회논문지
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• 제5권3호
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• pp.216-223
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• 2010

Most lamp units at ceilings, walls, and streets are static and no automatic motion capabilities are available at all to adjust lamp tilting angles and its zooming position. This paper proposes a new robotic lamp that creates three degrees of freedom (DOF) motion by using a spherical-type parallel mechanism with a unique forward kinematic position. In the robotic lamp, three motors are placed at the base frame to control two tilting angles and one zoom in-and-out motion for a localized light. The kinematic model of this device is derived and the proto type has been developed. The performance of this device was verified through experiment.

• 한국분말재료학회지
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• 제8권1호
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• pp.61-69
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• 2001

Spark-Plasma Sintering(SPS) is one of the new sintering methods which takes advantages both inconventional pressure sintering and electric current sintering. It is known that SPS is very effective for the densification of hard-to-sinter materials like refractory metals, intermetallic compounds, glass and ceramics without grain growth. However, a clear explanation for sintering mechanism and an experimental evidence for the formation of weak plasma during SPS are not given yet. In this study, fundamental study on sintering behavior and mechanism of SPS was investiged. For this study, various spherical Fe powders were prepared such as as-received, as-reduced, and as-oxidized and then sintered by SPS facility. In order to confirm the surface cleaning effect during SPS neck region and fracture surface of sintered body was observed and analyzed by SEM/EPMA. Densification behavior was analyzed from the data of deflection along the pressure axis. Some specimens were additionally produced by Hot Pressing and the results were compared with those of SPS.

• 대한기계학회논문집
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• 제18권11호
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• pp.2846-2859
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• 1994

This work deals with kinematic analysis of fault-tolerant 3 degree-of-freedom spherical modules which have force redundancies in its parallel structure. The performance of a redundantly actuated four-legged module with no actuator failure, a single actuator failure, partial and half failure of dual actuator are compared to that of a three-legged module, in terms of maximum force transmission ratio, isotropic characteristics, and fault-tolerant capability. Additionally, a system with an excess number of small floating actuators is considered, and the contribution of these small actuators to the force transmission and fault-tolerant capability is evaluated. This study illustrates that the redundant actuation mode allows significant saving of input actuation effort, and also delivers a fault tolerance.

• International Journal of Precision Engineering and Manufacturing
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• 제9권1호
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• pp.7-11
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• 2008

A new continuously variable transmission (CVT) for electric bicycles was developed using a traction drive mechanism with inner and outer spherical rotors. This electric bicycle CVT permits three propulsion modes: human-power only, motor-power only, or a combination of motor power and human power. In addition, the electric bicycle CVT has high power efficiency, large torque capacity, improved drivability, and good packageability. A prototype was manufactured based on a conceptual design, a performance analysis, and a detailed design. This prototype has a rated power of 250 W and input motor speed of 20 rad/s for an overall speed ratio in the range 0.3-1.2. A bench test was conducted to measure the power transmission performance of the prototype.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.346-350
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• 2004

In Blu-ray(BD) optical system, as a short laser wavelength of laser diode and thin cover layer thickness of' disc, the proper adjustment of spherical aberration should be performed. Considering thin cover layer' thickness and tolerance variation of disc in BD optical system, spherical aberration in BD format is mort: serious than CDㆍDVD format Especially, in dual-layer disc, to compensate the aberration at each layer, optical component should be moved finely in the way of optical path. In this study, 1 -axis moving actuator was introduced as the method of compensating the spherical aberration, and the mechanism of the system was described. Finally, its effect on optical system will be mentioned.

• Journal of Advanced Marine Engineering and Technology
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• 제30권8호
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• pp.863-869
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• 2006

A new CVT, the inner spherical traction CVT (ISCVT) is introduced. Transmission of the most scooters is the self-controlled variable pulley-belt type of CVT having some disadvantages in the fuel consumption and the limitation of the transmittable power due to the slippage between the belt and pulley. Unlike this, ISCVT controlled directly by driver is more efficient and the contact mechanism having the same line of contact normal of the spherical rotors of different radii on common center causes that the power density and torque capacity are remarkably improved. The prototype with the specifications of 50cc scooter is designed and tested.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.788-791
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• 2002

The phosphors of high luminous efficiency for PDP application must have high purity, single phase, and dense surface. In this work, the polymeric reaction was applied to preparation of spherical phosphor by aerosol pyrolysis in order to enhance mechanical and optical characteristics. The red phosphor of (Y,Gd)$BO_3$:Eu was prepared from polymeric precursor, in which citric acid and ethylene glycol were used as ion carriers, i.e monomers. For enhancing the luminescence intensity and mechanical characteristics. optimum synthesizing condition were investigated through concentration of monomers, synthetic temperature. doped activator concentrations, and annealing process. The phosphors synthesized with monomers showed quite different morphology from those without monomers. It was observed that polymeric precursor made an effect on particle formation mechanism and status of particles surface. The resultant spherical phosphors show the comparable luminescent properties to the commercial product (product by Nichia co.). Also, they were observed to have the rigid surface.

• 한국정밀공학회지
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• 제31권6호
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• pp.535-541
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• 2014

In this research, three degree-of-freedom parallel spherical robot is developed for an artificial eyeball. The proposed system is comprised of a moving and a base plate, three prismatic actuators, and a ball joint for an angular movement of the moving plate. The vector analysis is employed to investigate the relationship between positions of the actuators and a pose of the moving plate. The required ranges for every actuators are calculated using the derived inverse kinematics in regard to the combination of two different levels for the size of the system component. Then the size of every components is determined from the analyzed trend. PI controller is employed for the position control of the moving plate. Finally the proposed system is verified using an arbitrary path of the angular movement.

• 한국수소및신에너지학회논문집
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• 제30권1호
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• pp.67-75
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• 2019

An experimental study was conducted to measure laminar burning velocity and Markstein length of SNG fuel with 3% of hydrogen contents from spherical propagating flames at normal and elevated initial pressure. These results were compared with numerical calculations by Premix code with GRI-mech 3.0, USC II and UC San Diego to provide suitable mechanism for SNG fuel. As a result of this work, it was found that the burning velocities and Markstein lengths of SNG fuel decrease with increase of initial pressure regardless of equivalence ratio. In addition, numerical calculations with GRI-mech 3.0 were coincided with experimental results.