• Journal of Technologic Dentistry
• /
• v.23 no.2
• /
• pp.203-210
• /
• 2002

This test is to conduct applied research the reaction area of the Ti-cast metal body which is made use of Dental Phosphate-silica alumina bonded investment material selling at a market, and the cooling method is how to effect on the acicular. The experimentation is as followings, 1. Experimental specimens After invest with Dental Phosphate-silica alumina bonded investment material, the $10{\times}10{\times}1.0mm^3$ wax pattern was casted by Dental high vacuum argon centrifugal casting machine. 2. Test We can analyze SEM/EDS, XRD utilize the fractography(an optical microscope). 3. Conclusion The pure cast metal body constituted of reaction products layer, stability layer and contamination layer. This pure cast have no connection with the cooling condition. The pure Titanium shows difference in a component distribution according to the cooling condition. Through this experimentation we can establish that acicular in the pure Ti-cast metal is consist of Hexagonal structure a=2.9505$\AA$, c=4.6826$\AA$.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.40 no.2
• /
• pp.29-36
• /
• 2008

In order to give pulp surfaces anti-bacterial functionality and photo-catalytic deodorant ability, functional pulps was made using a surface modification method with Ag nano-colloidal solution and $TiO_2$ filler. Hygiene paper was made with the specially modified pulp, and anti-bacterial and deodorant tests were carried out. The Ag nano-colloidal solution was coated on the surface of the pulp using the high pressurized gas phase squirt through the spray nozzle mounted on the hybridization system. The surface modified functional pulp was hybridized with the optimum ratio of $TiO_2$(fine particle) to pulp(core particle) under the condition of $6,000{\sim}10,000$ rpm for $3{\sim}7$ minutes in the system. The anti-bacterial functionality of the hygiene paper was confirmed by the halo test in which the formation of the clear zone around the hygiene paper sample was observed. The inhibition growth test using MIC bioscreen C showed the inhibition growth effect of the bacteria as the reaction time was increased. The photo-catalytic effect measurement of the $TiO_2$ for 4 hours of the reaction showed $50{\sim}60%$ of decomposition rate, reaching over 60% for 5 hours of the reaction.

• Journal of the Korean Ceramic Society
• /
• v.48 no.2
• /
• pp.173-177
• /
• 2011

Decomposition promoting factors and decomposition mechanism in the zinc decomposition process of waste hard metals which are composed mostly of tungsten carbide and cobalt were evaluated. Zinc volatility amount was suppressed and zinc valatilization pressure was produced in the reaction graphite crucible inside an electric furnace for ZDP. Reaction was done for 2 h at $650^{\circ}C$, which 100 % decomposed the waste hard metals that were over 30 mm thick. As for the separation-decomposition of waste hard metals, zinc melted alloy formed a liquid composed of a mixture of ${\gamma}-{\beta}1$ phase from the cobalt binder layer (reaction interface). The volume of reacted zone was expanded and the waste hard metal layer was decomposed-separated horizontally from the hard metal. Zinc used in the ZDP process was almost completely removed-collected by decantation and volatilization-collection process at $1000^{\circ}C$.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.3
• /
• pp.669-673
• /
• 2011

This study explores the numerical analysis method of fluid dynamics in the reaction section to improve the gas processing efficiency in the hazardous gas removal by atmospheric thermal plasma. This study also intends to contribute in technology advance to improve the processing efficiency and make the process more stable. Numerical analysis of temperature distribution in the reaction section dependent on the change in flow velocity of Ar and plasma temperature change, which are major control variables in the cracking process of HFC-23 using arc plasma, was done. The characteristic of incoming oxygen by temperature suggested that when temperature increased to 1600K, 1700K, 1800K respectively, the range of cracking temperature 1500K increased to 75.0%, 83.3%, 90.2% respectively. The temperature change of Ar by velocity change was widest in the area higher than 1500K when the velocity was 2.5m/s; however, since there was no big difference when the velocity was 2m/s, it is believed that 2 m/s would be most proper.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.20 no.3
• /
• pp.1040-1049
• /
• 1996

The high loading combustion is accomplished by making the turbulent intensity strong and the scale small in the premixed combustor. The Da-mkoler number, which is decreased by short turbulent characteristic time or by long chemical reaction time, can make the distributed reaction flame. So we developed a doubled jet burner for high loading combustion. The doubled jet burner was designed to make the scale of the flame small by the effect of impingement and increasing shear stress with doubled jet. We investigated the turbulence characteristics of unburned mixture and visualized several flames with the typical schlieren photography. Then we studied the influence of several factors that related the scale of flame. Consequently, the doubled jet burner can make the eddy very small. And we can obtain the detail information of the flame scale through ADSF(the Average Distance between Successive Fringes) in the micro- schlieren photography. The ADSF is not a exact flame scale, but it has qualitative trend with increasing turbulent intensity. The ADSF is diminished remarkably with increasing turbulent intensity. The reason is that strong turbulent intensity makes the flame zone thick and flamelets numerous. We can confirm this fact by the signal analysis of ion currents.

• Journal of Soil and Groundwater Environment
• /
• v.18 no.5
• /
• pp.39-45
• /
• 2013

Many researchers have studied the effectiveness of ultrasound in chemical and environmental engineering fields including material synthesis, pollutant removal, cleaning, extraction, and disinfection. Acoustic cavitation induced by ultrasound irradiation in aqueous phase can cause various sonophysical and sonochemical reactions without any chemicals. However most of the previous studies focused only on the relationships between ultrasonic conditions and the results of sonochemical reactions in lab-scale sonoreactors. As a results of this, only a few studies have been devoted to design and optimization of industrial scale sonoreactors. In this study, the effect of the distance between two opposite transducer modules on sonochemical reactions was investigated in single and dual irradiation systems (334 kHz) for four distances including 50, 100, 150, and 200 mm using KI dosimetry. It was found that the dual irradiation systems provided higher performance in terms of the zeroth reaction coefficient and the cavitation yield compared to the single irradiation systems. The sonochemiluminescence (SCL) images for the visualization of the cavitation field showed that cavitation active zone was larger and sonochemical reaction intensity was much higher in the dual irradiation system than in the single irradiation system.

• Nuclear Engineering and Technology
• /
• v.54 no.2
• /
• pp.653-660
• /
• 2022

The interaction between UN and CdCl₂ in the LiCl-KCl molten eutectic was studied at 1023 K. The chlorination was monitored by sampling and recording the redox potential of the medium. At 1023 K the chlorination of UN with cadmium chloride in the molten LiCl-KCl eutectic proceeds completely and results in the formation of uranium chlorides. The melts of the LiCl-KCl-UCl₃ or LiCl-KCl-UCl₄ compositions can be obtained by the end of experiment depending on the presence of metallic cadmium in the reaction zone. The higher the concentration of the chlorinating agent, the faster the reaction rate. At [CdCl₂]/[UN] = 1.65 (10% excess) the reaction proceeds to completion in about 7.5 h. At [CdCl₂]/[UN] = 7 the complete chlorination takes 2.5-3 h.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.20 no.6
• /
• pp.39-45
• /
• 2012

More than 80 percent of traffic accidents related with lane departure believed to be the result of crossing the lane due to either negligence or drowsiness of the driver. Lane-departure related accident in the highway usually involve high fatality. Even though LDWS is believed to prevent accident 25% and reduce fatalities by 15% respectively, its effectiveness in performance is yet to be confirmed in many aspects. In this study, the vehicle lateral locations relative to warning zone envelop (earliest and latest warning zone) defined in ISO standard, ECE and NHTSA regulations are compared with respect to various factors including delays, vehicle speed and vehicle heading angle with respect to the lane. Since LDWS is designed to be activated at the speed over 60 km/h, vehicle speed range for the study is set to be from 60 to 100 km/h. The vehicle heading angle (yaw angle) is set to be up to 5 degree away from the lane (abrupt lane change) considering standard for lane change test using double lane-change test specification. The TLC is calculated using factors like vehicle speed, yaw angle and reaction time. In addition, the effect of vehicle type has been considered to assess LDWS safety.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.11
• /
• pp.1141-1145
• /
• 2005

A contactor coupled sequencing batch reactor composed of pre-anoxic contact zone and intermittently aerated zone was proposed and operated for nitrogen removal. Emphasis was placed on the fact that the contactor can be operated in a rapid reaction mode that results In biological uptake but incomplete metabolism of organic matter. Consequently, 61.2% of the sewage SCOD was adsorbed to activated sludge by 30-minute contact reaction. The specific uptake of organic matter was 22.3 mg SCOD/g MLVSS that enhanced the denitrification efficiency in the following denitrification stage. The removal efficiencies of the organic matter(SCOD) and the total nitrogen(T-N) were 86% and about 60% at the TCOD/TKN ratio as low as 6.0, respectively.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.140-140
• /
• 1999

Ti/Ni multilayered films (MLF) are ideal for neutron optics particularly in neutron guides and focusing devices. This system also possesses the tendency of amorphization through a solid-state reaction (SSR). This behaviors are closely related to the electronic structures and both magneto-optical (MO) and optical properties of metals depend strongly on their electron energy structures. Mutual inter-diffusion of the Tin and Ni atoms in the MLF caused by a low temperature annealing should decrease the thickness of pure Ni, as well as change the chemical and atomic order in the reactive zone. The application of the MO spectroscopy to the study of SSR in the MLF allows us to obtain an additional information on the changes in the atomic and chemical orders in the interface region. The optical one has no restriction on the magnetic state of the constituent sublayers. Therefore, the changes in magnetic, MO and optical properties of the Ti/Ni MLF due to SSR can be expected. To the best of our knowledge, the MO and optical spectroscopies were not used for this purpose. SSR has been studied in the series of the Ti/Ni MLFs with bilayer periods of 0.65-22.2nm and constant ratio of the Ti to Ni sublayers thickness by using MO and optical spectroscopies as well as an x-ray diffraction. The experimental MO and optical spectra are compared with the computer-simulated spectra, assuming various interface models. The relative changes in the x-ray diffraction spectra and MO properties of the Ti/Ni MLF caused by annealing are bigger for the multilayers with "thick" sublayers, or the SSR with the formation of amorphous alloy takes place mainly in the Ti/Ni multilayers with "thick" sublayers, while in the nominal threshold thickness of the Ni-sublayer for the observation of the equatorial Kerr effect in the as-deposited and annealed Ti/Ni MLFs of about 3.0 and 4.5nm thick is explained by the formation of amorphous alloy during the deposition or the formation of the nonmagnetic alloyed regions between pure components as a result of the SSR. For the case of Ti/Ni MLF the MO approach is more sensitive for the determination of the thickness of the reacted zone, while x-ray diffraction is more useful for structural analyses.structural analyses.