• Title/Summary/Keyword: electrolytic ionization

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Basic Study on the Improvement of Material Removal Efficiency of Sapphire CMP Using Electrolytic Ionization and Ultraviolet Light (전해 이온화와 자외선광을 이용한 사파이어 화학기계적 연마의 재료제거 효율 향상에 관한 기초 연구)

  • Park, Seonghyun;Lee, Hyunseop
    • Tribology and Lubricants
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    • v.37 no.6
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    • pp.208-212
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    • 2021
  • Chemical mechanical polishing (CMP) is a key technology used for the global planarization of thin films in semiconductor production and smoothing the surface of substrate materials. CMP is a type of hybrid process using a material removal mechanism that forms a chemically reacted layer on the surface of a material owing to chemical elements included in a slurry and mechanically removes the chemically reacted layer using abrasive particles. Sapphire is known as a material that requires considerable time to remove materials through CMP owing to its high hardness and chemical stability. This study introduces a technology using electrolytic ionization and ultraviolet (UV) light in sapphire CMP and compares it with the existing CMP method from the perspective of the material removal rate (MRR). The technology proposed in the study experimentally confirms that the MRR of sapphire CMP can be increased by approximately 29.9, which is judged as a result of the generation of hydroxyl radicals (·OH) in the slurry. In the future, studies from various perspectives, such as the material removal mechanism and surface chemical reaction analysis of CMP technology using electrolytic ionization and UV, are required, and a tribological approach is also required to understand the mechanical removal of chemically reacted layers.

Potential Reduction and Energy Dispersion Due to Ionization Around the Submerged Ground Rod (수중에 잠긴 접지전극 주변에서의 이온화에 의한 전위저감 및 에너지방출)

  • Choi, Jong-Hyuk;Ahn, Sang-Duk;Yang, Soon-Man;Lee, Bok-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.1
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    • pp.92-99
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    • 2009
  • Deeply-driven ground rod in the rainy season may contact with rainwater and ground water. When surge voltages are applied to the submerged ground rods, the ionization around the ground rods are occurred. Ionization in soil and/or water is affected in dynamic performance of ground rod systems. This work aims at studying the transient performance of ground rod system under impulse voltage using scale model in an electrolytic tank. The potential reduction and energy dispersion caused by ionization were treasured and quantitatively analyzed using the Matlab Program. As a result, the peak voltage at the terminal of ground rod was varied with water resistivity and charging voltage of Marx generator. The potential at the terminal of the ground rod was approximately reduced to a half of the applied voltage just below breakdown voltage. Also the energy more than half of the applied energy was dispersed through the ground rod due to ionization just below breakdown voltage.

The Analysis of Electrical Conduction and Corrosion Phenomena in HVDC Cooling System and the Optimized Design of the Heat Sink of the Semiconductor Devices (HVDC 냉각시스템의 전기전도현상 및 부식현상 기술 분석과 스위칭 소자의 방열판 최적 설계 검토)

  • Kim, Chan-Ki;Park, Chang-Hwan;Kim, Jang-Mok
    • The Transactions of the Korean Institute of Power Electronics
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    • v.22 no.6
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    • pp.484-495
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    • 2017
  • In HVDC thyristor valves, more than 95% of heat loss occurs in snubber resistors and valve reactors. In order to dissipate the heat from the valves and to suppress the electrolytic current, water with a high heat capacity and a low conductivity of less than 0.2 uS/cm must be used as a refrigerant of the heat sink. The cooling parts must also be arranged to reduce the electrolytic current, whereas the pipe that supplies water to the thyristor heat sink must have the same electric potential as the valve. Corrosion is mainly caused by electrochemical reactions and the influence of water quality and leakage current. This paper identifies the refrigerants involved in the ionization, electrical conductivity, and corrosion in HVDC thyristor valves. A method for preventing corrosion is then introduced. The design of the heat sink with an excellent heat radiation is also analyzed in detail.

A Study on a Classification Technique of Natural Mineral Waters by Its Constitution and Physico-Chemical Properties (鑛泉水 理化學的 水質評價 技法 에 관한 연구)

  • Nam, Sang-Ho
    • Journal of Environmental Health Sciences
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    • v.14 no.1
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    • pp.33-38
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    • 1988
  • Natural mineral water is generally quite different from ordinary drinking water due to its original nature and various properties. The complexity of natural mineral water requires, therefore, not only to identify its nature and proper characteristics, but also to classify them by a reasonable scientific basis of comparison. The study was concentrated on a possible classification technique to natural mineral waters by their constitutions and physico-ehemical properties. The classification was carried out by the computation of such numerical parameters as ionic equivalent percentage, electrolytic conductance or mobility, ionic molecular weight, molecular concentration, equivalent conductivity and degree of ionization in consideration of the determinative criteria as follows -particular single element or molecule -major components of natural waters as bicarbonate, sulphate, chloride,caloride, calcium, magnesium, and sodium -moleculat concentration related to blood osmotic pressure -water temperature at emergence from spring -contents of free carbon dioxide (CO2) -pH value of water -total dissolved solids or salts (NaCl) The results obtained proved out to be clearly distinguhhable from ordinary drinking water as far as concern natural mineral water as an example on the subject -simple water -bicarbonate-predominating water -cold spring -carbonated-non gaseous water -weak alkaline water -non saline water Putting these various results together, the sample turned out to be a kind of natural mineral water that can be used as a drinking water if microbiologically safe.

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Rationale and Definition of The Criteria of The Efficiency of The Biological Activity of Optical Radiation on Animal Organism.

  • Chervinsky, Leonid S.
    • The Korean Journal of Food & Health Convergence
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    • v.4 no.3
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    • pp.1-5
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    • 2018
  • In today's technological development of human society more and more influence on the lives of biological organisms different electromagnetic radiation. Therefore, the study and analysis of the mechanisms of their effects is an urgent task. The purpose of research - the study of the primary mechanisms of interaction of photons of optical radiation with the structures of biological objects, using the laws of quantum mechanics and biophysics. Photobiological basis of the mechanism of action of EMR optical range is the energy absorption of light quanta (photons) by atoms and molecules of biological structures (law Grotgus-Draper), which resulted in the formation of electronically excited states of these molecules with the transfer of photon energy (internal photoeffect). This is accompanied by electrolytic dissociation and ionization of biological molecules. The degree of manifestation of photobiological effects in the body depends on the intensity of the optical radiation, which is inversely proportional to the square of the distance from the source to the irradiated surface. Accordingly, in practice, determine not the intensity and irradiation dose at a certain distance from the source of exposure by the exposure time.