• Journal of Information Display
• /
• v.7 no.2
• /
• pp.22-25
• /
• 2006

This paper presents heating process for obtaining standing carbon nanotube emitters to improve field-emission properties from the screen-printed multiwalled carbon nanotube (MWCNT) films. In an atmosphere with optimum combination of nitrogen and air for heat treatment of CNT films, the CNT emitters can be made to protrude from the surface. This allows for high emission current and the formation of very uniform emission sites without special surface treatment. The morphological change of the CNT film by this technique has eliminated additional processing steps, such as surface treatment which may result in secondary contamination and damage to the film. Despite its simplicity the process provides high reproducibility in emission current density which makes the films suitable for practical applications.

• Journal of the Korean Institute of Educational Facilities
• /
• v.1 no.1
• /
• pp.21-32
• /
• 1994

It is time to put our top priority on the computer education to cope with rapid chage in technology and expansion of information. With 6th educational reform plan, from 1995 computer courses will be offered as elective subjects in the most of middle schools. However, detail planning for training of computer courses will be offered as elective subjects in the most of middle schools. However, detail planning for training of computer teachers and providing facilicles for computer education hasn't been adequately prepared yet, This will bring about confusion in computer education. The purpose of this study is to propose how to renovate the ordinary classroom into computer classroom. Followings are the suggestions for the educational specification for the renovated computer classroom for middle school in the urban area. 1) Purpose of computer classroom, 2) Size of computer classroom, 3) Curriculum design and class hour, 4) Facilities, 5) Environments, 6) Equipment and media(lighting and electric system, acoustical treatment, cooling/heating and ventilation system), 7) Activity area(Teacher workstation, Student workstation, Support area, Display surface). For the promotion of computer education, the legal, financial and administrative supports by concerned authorities should be established ahead of discussing the contents of computer education.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.27 no.10
• /
• pp.96-100
• /
• 1990

The cordierite ($2MgO,2Al_{2}O_{3},5SiO_{2}$) is of great interest for packaging substrates of multilayer IC. The Cu layer was fabricated on the cordierite substrate by the screen printing method and the adhesion properties of the interfaces at the different cosintering conditions were studied. When cosinted in the $Ar+H_{2}O$atmosphere good adhesion was obtained and the heating was found out to be an important factor for the adhesion.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.1
• /
• pp.99-108
• /
• 2004

Fundamental combustion characteristics, such as the combustion potential, burning velocity and flame stability, for the practical utilization of LFG(Landfill gas) and LFG-blended fuels were experimentally investigated. The combustion potentials(CP) of LFG-blended fuels calculated from the previously suggested formulae were compared with burning velocities obtained by present experiments. The results showed that the previous formulae fur CP of LFG-blended fuels were not agreed with the experimental burning velocity, and these formulae should be revised. To provide an useful information needed to design the combustion devices, a triangular diagram was suggested for the maximum burning velocity of the mixture of CH$_4$, LPG and LFG. From the investigation of the burning velocity and the flame stability in a practical combustor, it was noted that the LFG-blended fuels, of which heating values or Wobbe indices were adjusted to that of natural gas, could be used as an alternative fuel of natural gas.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.514-519
• /
• 2001

Converter has been slag produced 10 million tons per year in Japan. It is a steel making by product produced in the same way as the blast-furnace slag. Though blast-furnace slag is being used effectively as a concrete admixture, the converter stag has never been used effectively because of the expansion action of contained free lime and iron oxide. This is an important environmental problem in the steel industry. Beta-2CaOSiO$_2$(beta-C$_2$S) is contained 40 percent in converter slag, therefore it is very promising as a concrete admixture. We proposed an accelerated aging processes capable of stabilizing the converter slag in a short time. The converter slag is dipped into alkali aqueous solution after heating at low temperature. It was subsequently ground to a grain size of 75 ${\mu}{\textrm}{m}$ , inner 30 percent of OPC. The properties of mortar and concrete using the blended cement were determined. As a result, it has become apparent that the expansion was reduced and long term compressive strength was increased while that at early ages was not so remarkable. The hydration exotherm rate was lower than that of the OPC.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.675-679
• /
• 2001

The research is to discuss the current resource recycling and recovery policy, which was enacted by Environmental Protection Administrative (EPA) in Taiwan. For the past few years, the solid waste generated in Taiwan has greatly increased about 5 % per year. In addition to the construction of landfill sites and incineration plants, 4 R techniques (Reduction, Reuse, Recycle and Recovery) were also publicized among the citizens and then promulgated to furthermore manage these increased solid waste. Although the regulations have been carried out to a great success, they still need to be revised and updated since solid waste contains varieties of different materials. Therefore, this research discusses the current regulation and makes suggestion for future regulation revision. From the results of this study, energy recovery was suggested to be emphasized in the regulation. Energy could be recovered from materials such as waste tires, and all kinds of plastic containers. Waste tires and most of the plastic containers made of hydrocarbon species, which contains great heating values, should be considered as one of the alternatives for the resource recycling.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.571-575
• /
• 2001

To examine the grinding effect through preheating of waste concrete as a way of retrieving coarse aggregates from waste concrete, the removal rates of cement mortar and paste of both recycled aggregates and heated and grinded ones were investigated. As the preheating temperature increased, the removal rate of cement mortar from waste concrete was raised, and this kind of removal hardly affected the abrasion rate and specific gravity of aggregates. On the other hand, when it was treated over 40$0^{\circ}C$ of preheating temperature, the absorptance was reduced to less than 2.17, and cement mortar was effectively separated from waste concrete. It could meet the Korean Standards on recycled aggregates for concrete, and it is expected to expand the scope of utilization by making it possible to retrieve the aggregates which have the properties close to natural aggregates.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.605-609
• /
• 2001

Low density ceramic supporter was prepared by using fly ash as a starting material for the application to the biological aerated filter (BAF) system, and the effect of additives and sintering atmosphere on the apparent and bulk density of the carrier was examined. Borax, Na$_2$O and glass powders were added to produce liquid phase. The density of the supporter decreased as the amount of borax increased. The bulk density of 0.79 g/㎤ and the apparent density of 1.10 g/㎤ were obtained when the fly ash with 15% of borax was sintered at 116$0^{\circ}C$ for 15 minutes. The density also decreased as the plate glass powders past through 22${\mu}{\textrm}{m}$ size were mixed. When the fly ash with 12% of grass powder was sintered at 128$0^{\circ}C$ for 10 minutes, the bulk and apparent density were 0.90g/㎤ and 1.00 g/㎤, respectively. Apparent density of 1.6~1.8g/㎤ was obtained when the fly ash was sintered at 120$0^{\circ}C$ in a weak reducing atmosphere. By maintaining the reducing atmosphere and sintering at a high heating rate, the liquid phase was farmed from the reduced composition of fly ash. This resulted in the formation of closed pores that enabled the low apparent density.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.6
• /
• pp.127-135
• /
• 1996

To increase the sensitivity and the selectivity of the sensors to TMA gas, the composition ratio and the growth conditions of the ZnO films are studied. Annealing of the ZnO films in the various time ranges and temperatures in the oxygen is carried out to enhance the stbility of the electrical resistance. Pt/Ti heater deposited on backside of the substrates in used to control the operating temperature of th esensor. The ZnO thin film sensors doped to 4.0 wt% $Al_{2}$O$_{3}$ 1.0wt.% TiO$_{2}$ and 0.2wt.% V$_{2}$O$_{5}$ exhibited a high sensitivity and an excellent selectivity for TMA gas. The sensors made with the thin films annealed at 700$^{\circ}$C for 60 minutes in the oxygen atmosphere had a good stability and linearity. The heater deposited in the ratio of 1 to 1 (Pt:Ti) had a good heating properties. The sensors fabricated using above conditions showed a good response to the actual gases of a mackerel at a step of deterioration after death.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.209-212
• /
• 2001

Aircraft industry is developed very fast so titanium scrap was generated to manufacture. Titanium scrap was wasted and used to deoxidize cast iron so we are study recycling of it. In this research were studied that metal hydride of reacted in hydrogen chamber of AMS4900, 4901, return scrap titanium alloy and sponge titanium granule. The temperature of hydrogenation was 40$0^{\circ}C$ in the case of pure sponge titanium but return scrap titanium alloy were step reaction temperature at 40$0^{\circ}C$ and 50$0^{\circ}C$, and after the hydride of titanium alloy were crushed by ball mill for 5h. Titanium hydride contains to 4wt.% of hydrogen theoretically as theory. It was determined by heating and cooling curve in reaction chamber. The result of XRD was titanium hydride peak only that it was similar to pure titanium. Titanium hydride Powder particle size was about 45${\mu}{\textrm}{m}$, and recovery ratio was 95w% compared with scrap weight for a aluminum foam agent.