• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제13권7호
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• pp.579-587
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• 2001

This study investigates particle collection characteristics of a cylindrical electrostatic precipitator. Experimental work has been made for the submicron particles. The effects of polarity of discharge electrode wire, particle diameter, gas velocity, gas temperature, and specific corona power on the particle collection efficiency are investigated. The efficiency of negative corona is higher than that of positive corona. as the particle diameter increases, the efficiency is decreased when the diameter is in the range of 0.02-0.6 micron, but is increased for the nanometer particles with diameter smaller than 0.02 micron. The efficiency is increased with increase of specific corona power. As the gas temperature increases, overall collection efficiency is increased for a negative corona, but is deceased for a positive corona.

• Journal of Adhesion and Interface
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• 제17권3호
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• pp.104-109
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• 2016

Compare AC corona and DC corona treatment effects, polyester fabrics were AC corona treated with different current intensity (5, 10, 15 A) and feeding speed (5, 10, 15 m/min) as the same DC corona treatment conditions of the preceding research. We confirmed the surface change of polyester fabrics using scanning electron microscopy (SEM) and X-ray photoelectron spectrometer (XPS), and the change of physical properties through measuring the dry and wet bonding strength. The surface changes of polyester fabrics by treating in air atmosphere with AC corona discharge are shown similar tendency with DC corona discharge. Generally dry bonding strength were increased with increasing current intensity and feeding speed, but wet bonding strength were increased with increasing current intensity and decreasing feeding speed in both AC and DC corona treatment. When the current is 20 A, carbonization occurs in DC corona discharge but carbonization does not occur in DC corona discharge.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1759-1764
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• 2015

Glow corona is a kind of streamer-free corona that can suppress upward leaders in transmission lines. Thus, it has good application potential in lightning protection. This paper investigates its corona characteristics. The suppression characteristic of glow corona on streamer is studied in air gap under negative DC voltage by wrapping thin wires on the electrode. The effect of thin wire winding patterns on the gap breakdown voltage is analyzed. Results are considered to be attributed to the inception condition of glow corona. Thus an inception test of glow corona is also conducted, and the inception voltage is obtained. Results show that the inception voltage decreases with short winding pitch. Thus an investigation on the inception of glow corona influenced by thin wire is conducted, and an influential factor is proposed to evaluate the influence. The inception regular of thin wire glow corona presented in this paper has certain reference value for the application of glow corona in transmission lines.

• Electrical & Electronic Materials
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• 제8권4호
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• pp.504-508
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• 1995

The purpose of this research is to study on characteristics of corona ignitor which was designed for ignition of plasma, used at hard coating, surface treatment and thin film preparation, at high pressure. Corona ignitor composed of hollow type inner electrode and ring type external electrode. Though corona voltage increased with increasing distance between electrodes, corona discharge can be controlled stably. The gas flow in hollow type inner electrode and the construction between electrodes affect a length of corona flame and corona phenomenon. It is possible to ignite the . plasma, usually generated at low pressure(10 Torr), at high pressure(100 Torr) by corona ignitor.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제26권5호
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• pp.91-96
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• 2012

The surface of bushing is contaminated with rain, dust, salt and others. A bushing with contaminations in air is serious problem in insulation. Therefore, it is important to understand the inspection and diagnoses of the safety. The ultra-violet rays(UV) camera has attracted interest from the view point of easy judgement. In this paper, we will report on the corona discharge characteristics of surface flashover model with contaminations in air. Also, UV images of discharge and corona pulse count in air are analyzed using prototype UV camera of Korea and a UV sensor with an optic lens. These results are studied at both AC and DC voltage under a non-uniform field.

• 전기의세계
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• 제16권5호
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• pp.15-18
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• 1967

This paper shows the analysis for mechanisms of corona pulse caused by dielectric breakdown, and for the results of observed values on an actual machines with the this corona pulse technique. Although the above results are not directly related with the generation, numbers or wave of the corona pulse, it may possibly be chanced a judgement of dielectric breakdown and one of better synthetic judgement methods for actual electrical machines.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제28권2호
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• pp.54-59
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• 2014

The electric power can be converted into the mechanical power by a corona discharge system. This way has not stronger force than a electric motor. But it has been applied in various industrial fields because of many advantages, no moving parts, smaller noise, simpler structure, minimizing et al. In this paper, corona discharge system with multiple corona electrode installed in form of the ring, has been studied by focusing on the electrical and mechanical characteristics. Intensity of the corona discharge depends on applied electric field, and electric field is related to the applied voltage, discharge gap spacing(s), distance between each corona electrodes(d). As a result, in the case d/s=0.9, most intensive discharge occurred in this experiments. In the region of d/s<0.9, ionic wind velocity has saturation value in spite of decreasing corona current, because each ion velocities increase by the increasing electric field.

• Proceedings of the KIEE Conference
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• 대한전기학회 1998년도 하계학술대회 논문집 E
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• pp.1598-1600
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• 1998

When dielectric surface electric field exceed any electric field strength on air, corona discharge is occurred from the dielectric surface. This paper presents corona discharge phenomena on the dielectric in high field were studied under application of ${\pm}DC$ voltage, constitute of the point to plane 20mm gap. The results obtained in experimental are summarized as follow :(1) Corona pulse is appeared periodically after first corona pulse is occurred and the number of corona pulse increases with the instantaneous applied voltage but peak value is not changed greatly.(2)Applied voltage to beccrite and characteristics and peak value of current are almost a straight line. That kind of tendency accorded with characteristics of beccrite resistance.(3)In case of Positive corona, Positive streamers, were progressed greatly to plane electrodes but In case of negative corona, negative streamers smaller than that of Positive corona.

• Anatomy and Cell Biology
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• 제57권2호
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• pp.183-193
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• 2024

The corona of the glans clitoris is a clinically important yet poorly understood anatomical structure. There has been longstanding confusion regarding the prevalence of the corona of the glans clitoris and, moreover, its very existence. Therefore, this anatomical study assesses the prevalence of the corona of the glans clitoris and the gross anatomy of the proximal glans clitoris. Anatomy was assessed in 104 female donor bodies ranging in age from 50 to 102 years with an average age-at-death of 78.1±10.9 years (mean±SD). All clitorises (100%; 104:104 dorsums and 100%; 208:208 sides) were found to have a well-defined clitoral corona. Three of 104 (2.9%) coronas possessed grossly visible, outward-projecting, bluntly rounded papillae. Some donors possessed a coronopreputial frenulum. Clitoropreputial adhesions were common and associated with clitoral pearls. Clitoral pearls were identified in 37.8% (14:37) of unembalmed donors and observed to create clitoral craters, structural deformations in the surface of the corona and glans. The results of this study suggest that the corona of the glans clitoris is a ubiquitous anatomical structure. The clitoral coronal papillae and coronopreputial frenulum are novel, previously undescribed, anatomical structures. This study identifies that the corona of the glans clitoris is prone to pathological processes such as clitoral pearl formation and clitoral deformation. In addition to novel anatomical findings, the results of this study call attention to the need for life-long clitoral examinations. Furthermore, the corona of the glans clitoris should be regularly included in anatomical texts and accurately depicted in anatomical illustrations.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
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• pp.179-184
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• 2001

The characteristics of $NO-NO_2$ conversion and soot oxidation by corona discharge are investigated experimentally. The discharge current decreases with the increase of oxygen concentration and it increases more sharply for anode corona than for cathode corona as discharge voltage increases after corona onset voltage. $NO-NO_2$ conversion increases with the energy density of corona discharge and the addition of $O_2$ in a base $N_2$ gas. Soot oxidation occurs at approximately $480^{\circ}C$ in a mixture of 21% $O_2$, base $N_2$ gas, and enhances as temperature increases. The initiation temperature of soot oxidation advances greatly to about $280^{\circ}C$ with the addition of 300ppm $NO_2$, which is generated from the conversion of NO to $NO_2$ by corona discharge. CO is generated at higher temperature by about $50{\sim}100^{\circ}C$ than $CO_2$ in the process of soot oxidation.