Kyung-Sun Chung

This paper proposes a method for the coordinated control of a wind turbine and an energy storage system (ESS). Because wind power (WP) is highly dependent on wind speed, which is variable, severe stability problems can be caused in power systems, especially when the WP has a high penetration level. To solve this problem, many power generation corporations or grid operators have begun using ESSs. An ESS has very quick response and good performance for reducing the impact of WP fluctuation; howeve

Axial and azimuthal flow velocities have been measured in a linear plasma device called NAGDIS-II (NAGoya DIvertor Simulator-II), along with plasma density and electron temperature, using a vector Mach probe composed of two Mach probes, one of which is for the axial flow, and the other is for the azimuthal flow. To study the effect of neutral pressure on the deduction of the Mach numbers, the ratio of upstream to downstream currents are measured by changing the neutral pressure for the deduction

A non-toxic boron-containing material, carborane (C<SUB>2</SUB>B<SUB>10</SUB>H<SUB>12</SUB>) has been utilized to deposit amorphous hydrogenated carbon/boron (a-C/B:H) thin films in helium DC glow discharge. Helium plasma was produced by a filament discharge system connected with the carborane evaporation source at a target pressure of ~5 mTorr. The plasma discharge was performed by a pulsed mode at a duty cycle of 0.375 (3 s on/5 s off) or 0.23 (3 s on/10 s off). Deposited a-C/B:H thin films ar

The non-thermal properties of a low-pressure spraying plasma have been characterized by using optical emission spectroscopy and single probes installed in a fast scanning probe system. A two-temperature model of the electrons is introduced to explain their non-isothermal properties, which are measured using single probes. The excitation temperatures of the atomic and the ionic lines are calculated from measurements of the emission intensities of Ar (I) and Ar (II), and those temperatures can be

Plasma-facing materials in fusion devices are irradiated by a high particle flux from a dense plasma. Graphite tiles, widely used as plasma-facing materials, were irradiated with a helium plasma of a high flux and low energy; the damage in the graphite-tile target was investigated. Changes in the surface morphology were observed from scanning electron microscopy; the electrical conductivity was decreased from four-probe measurement; the intensity of the graphite disorder peak was increased from

A one-dimensional collisionless kinetic model is developed for electron collection to a positively biased object in magnetized plasmas. The cross-field ow into the collection tube is modelled by accounting consistently for particle exchange between the collection ux tube and the outer plasma. Numerical solutions of the self-consistent plasma/sheath equations are obtained for a stationary plasma. The spatial dependence of the electron distribution function, its moments (density, particle ux, a

Spatial variations of plasma parameters were measured in a large, inductively coupled plasma (ICP) chamber (diameter: 610 mm) by using a fast scanning probe (FSP), which could scan a length of 100 cm at a speed of 0.8 m/sec. The plasma parameters were measured by using single, triple, and emissive probes installed at the tip of FSP. A new modied diusion model was introduced to analyze the spatial variations of the normalized density since the variable mobility model cannot explain the current me

Determining drug dosage for STI (structured treatment interruption) according to the clinically healthy CD4 T cell count has recently been proposed due to its simple scheduling and effectiveness. In this paper, we investigated its effectiveness and validity from a mathematical biological point of view and analyzed the human immune system based on a mathematical model of a HIV-infected patient. Compared to the previous STI methods, we found that STI determined by the healthy CD4 T cell count not

Transports of plasmas in the edge of fusion devices have similarities in terms of formation of a free presheath and unclear explanation on the transport process relating the diffusion coefficient (D⊥) to characteristic length of perturbing for flux tube (Lc). D⊥ and Lc are investigated by generating perturbations in various free presheaths due to a perturbing object located at the axial center of a linear plasma device, called DiPS (Divertor Plasma Simulator). Free presheaths are generated due t

The multipactor saturation current (MSC) has been measured for RF frequencies to address limitations on the theoretical prediction. The dependence of the MSC on the RF frequency is studied by measuring the MSC in a multipactor simulator, which consist of two parallel 70-mmdiameter copper electrodes by changing the frequency from 25 to 43 MHz. The measured saturation current has the same order as the theoretical prediction of Vaughan, but the measured MSC has a higher rate of increase than Vaugha

A concept of ion extraction has been adopted to generate and analyze supersonic plasma flow ($M_\infty > 1$) in steady state condition. A capacitively coupled plasma (CCP) with weakly magnetic intensity ($B = 100$ G) was used as a plasma source along the axial direction and a cylindrical electrode was installed to generate negative potential within plasma by depleting ions. Characteristics of ion velocity distribution have been analyzed by equation of energy conservation from depletion ratio of