• 한국안전학회지
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• 제31권3호
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• pp.42-46
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• 2016

In LCD Display or semiconductor manufacturing processes, the anti-static technology of glass substrates and wafers becomes one of the most difficult issues which influence the yield of the semiconductor manufacturing. In order to overcome the problems of wafer surface contamination various issues such as ionization in decompressed vacuum and inactive gas(i.e. $N_2$ gas, Ar gas, etc.) environment should be considered. Soft X ray radiation is adequate in air and $O_2$ gas at atmospheric pressure while UV radiation is effective in $N_2$ gas Ar gas and at reduced pressure. At this point of view, the "vacuum ultraviolet ray ionization" is one of the most suitable methods for static elimination. The vacuum ultraviolet can be categorized according to a short wavelength whose value is from 100nm to 200nm. this is also called as an Extreme Ultraviolet. Most of these vacuum ultraviolet is absorbed in various substances including the air in the atmosphere. It is absorbed substances become to transit or expose the electrons, then the ionization is initially activated. In this study, static eliminator based on the vacuum ultraviolet ray under the above mentioned environment was tested and the results show how the ionization performance based on vacuum ultraviolet ray can be optimized. These vacuum ultraviolet ray performs better in extreme atmosphere than an ordinary atmospheric environment. Neutralization capability, therefore, shows its maximum value at $10^{-1}{\sim}10^{-3}$ Torr pressure level, and than starts degrading as pressure is gradually reduced. Neutralization capability at this peak point is higher than that at reduced pressure about $10^4$ times on the atmospheric pressure and by about $10^3$ times on the inactive gas. The introductions of these technology make it possible to perfectly overcome problems caused by static electricity and to manufacture ULSI devices and LCD with high reliability.

• Wind and Structures
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• 제12권5호
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• pp.425-439
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• 2009

The expediency of revising universal rules for the combination of gravity and lateral actions of wind force-resisting steel structures recommended by the Standards EN 1990 and ASCE/SEI 7-05 is discussed. Extreme wind forces, gravity actions and their combinations for the limit state design of structures are considered. The effect of statistical uncertainties of extreme wind pressure and steel yield strength on the structural safety of beam-column joints of wind force-resisting multistory steel frames designed by the partial factor design (PFD) and the load and resistance factor design (LRFD) methods is demonstrated. The limit state criterion and the performance process of steel frame joints are presented and considered. Their long-term survival probability analysis is based on the unsophisticated method of transformed conditional probabilities. A numerical example illustrates some discrepancies in international design standards and the necessity to revise the rule of universal combinations of loads in wind and structural engineering.

• 한국생산제조학회지
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• 제21권5호
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• pp.747-754
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• 2012

A solar power generator is usually installed outdoors and it is exposed to extreme environments such as snow weight and wind loading. The solar tracker structure should be designed to have sufficient stiffness and strength against such loads. In this paper, simulations are performed by varying the parameters such as wind directions, wind speeds and the pose of the solar panel to evaluate the effects of extreme wind on solar tracker. As the effects of wind load, maximum displacement and maximum equivalent stress in the solar tracker are calculated. Finite element stress analysis is carried out by using the pressure distribution that is obtained by prior wind load analysis due to the flow around the solar tracker. The stress analysis of solar tracker to check and/or improve structural robustness provides some useful instructions for structural design or revision of solar tracker.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.178.2-178.2
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• 2013

Conventional ultraviolets A,B,C are known to be very important factor of killing, changing surface properties of biological cells and materials. It is of great importance to investigate the influence of extreme ultraviolet (EUV) exposure on the biological cell. Here we have studied high density EUV plasma and its emission characteristics, which have been generated by plasma focus device with hypercycloidal pinch (HCP) electrode under various Ar gas pressures ranged from 30~500 mTorr in this experiment. We have also measured the plasma characteristics generated from the HCP plasma focus device such as electron temperature by the Boltzman plot, plasma density by the Stark broading method, discharge images by open-shuttered pin hole camera, and EUV emission signals by using the photodiode AXUV-100 Zr/C.

• Interaction and multiscale mechanics
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• 제4권1호
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• pp.65-83
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• 2011

In this study, two extreme cases of compatibility of the horizontal displacements between the foundation and soil are considered, for which the pressure and settlements of the isolated footings and member end actions in structural elements are obtained using the three dimensional models and numerical experiments. The first case considered is complete slip between foundation and soil, termed as the un-coupled analysis. In the second case of analysis, termed as the coupled analysis, complete welding is assumed of joints between the foundation and soil elements. The model and the corresponding computer program developed simulate these two extreme states of compatibility giving insight into the variation of horizontal displacements and horizontal stresses and their intricacies, for evaluation of the influence of using the interface elements in soil-structure interaction analysis of three dimensional multiscale structures supported by isolated footings.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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• pp.90-99
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• 2000

This report describes the results of analysis, synthesis and evaluation of antimony dithiocarbamates (SbDTC). Sb-DTC were synthesized by reacting antimony oxide with dithiocarbamates whish were prepared by reaction of dialkylamines and carbon disulfide. The chemical structures and properties of synthesized Sb-DTCs in lab. were discussed. The frictional properties of SbDTC were tested with Four-Ball Wear Scar Tester and Four-Ball Extreme Tester by ASTM method.

• Bulletin of the Korean Chemical Society
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• 제6권2호
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• pp.74-79
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• 1985

The stabilities of the charge transfer complexes of pentamethyl benzene with iodine in n-hexane have been investigated by UV-spectrophotometric measurements at 25, 40 and 60$^{\circ}C$ up to 1600 bars. The equilibrium constant of the complex formation was increased with pressure while being decreased with temperature raising. Changes of volume, enthalpy, free energy and entropy for the formation of the complexes were obtained from the equilibrium constants. The red-shift at higher pressure, the blue-shift at higher temperature, and the relation between pressure and oscillator strength have been discussed by means of thermodynamic functions. In comparison with the results in the previous studies, the absolute values of ${\Delta}$V at each temperature were increased with the number of methyl groups of polymethyl benzene. However, it can be seen that both ${\Delta}$H and ${\Delta}$S show extreme behaviors in durene near atmospheric pressure but they are negatively increased with the number of methyl groups near 1600 bar. This order of the thermodynamic parameters may be a measure of the relative basicities of polymethyl benzenes toward iodine under each pressure, and these phenomena are explained in terms of a positive inductive effect and a steric hindrance effect of the polymethyl benzene molecule.

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4412-4421
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• 2022

The pressure measurement in the high-temperature liquid metal system, such as Sodium-cooled Fast Reactor(SFR), is important and yet it is very challenging due to its nature. The measuring pressure is relatively at low range and the applied temperature varies in wide range. Moreover, the pressure transfer material in impulse line needs to considered the high temperature condition. The conventional diaphragm-based approach cannot be used for it is impossible to remove the effect of thermal expansion. In this paper, the Fiber Bragg Grating(FBG) sensor-based pressure measuring concept is suggested that it is free of problems induced by the thermal expansion. To verify this concept, a prototype was fabricated and tested in an appropriate conditions. The uncertainty analysis result of the experiment is also included. The final result of this study clearly showed that the FBG-based pressure transmitter system is applicable to the extreme environment, such as SFR and any other high-temperature liquid metal system and the measurement uncertainty is within reasonable range.

• 상하수도학회지
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• 제19권6호
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• pp.758-766
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• 2005

This study was conducted to evaluate the effect of the transverse troughs on hydrodynamic behavior within the a certain full-scale sedimentation basin (flow rate/one basin; $10,000m^3/d$) using CFD simulation and ADV technique. In order to verify the CFD simulation, we measured the factual velocity at 36 points in the full-scale sedimentation basin, whose outlet structure is inadequate, with ADV technique. Both the CFD simulation and the ADV measurement results were in good accordance with each other. From the CFD simulation results of the existing basin, it was investigated that extreme upward flow occurs in the near of two transverse troughs. It was suspected that since the transverse troughs converted the open channel flow into the local closed pipe flow, the increased pressure in this local closed pipe flow region made the extreme upward flow. For solving this problems, it was suggested to modify transverse-typed launder into finger-typed launder and to install a longitudinal baffle in the center in this study. The CFD simulation results of all suggested amendments told us that the extreme upward flow, had occurred especially in the beneath of transverse troughs, was much less in the case of finger typed launder basin than that in the existing basin. Also, it was predicted that installing a longitudinal baffle made the fully developed flow which is more effective for sedimentation.

• 드라이브 ㆍ 컨트롤
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• 제9권4호
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• pp.32-41
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• 2012

Most diagnosis methods for servo valves requires installing spool displacement sensor or flow sensor as well as pressure sensor. The measurement of flow is hard to implement and many kinds of servovalves or proportional direction valves do not have a built-in spool displacement sensor. In this study, static performances of servovalve or proportional-direction-valve are studied theoretically and a diagnosis technique, which uses only load pressure and input current signal, is assessed. An experimental setup was made based upon a personal computer and the LabVIEW graphical language. A series of diagnosis tests were performed and the analysis results showed it possible to measure the pressure gain, hysteresis and null bias in a relatively simple methodology.