• Title/Summary/Keyword: working gas ratio

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Reaction Gas Composition Dependence on the Properties of SnO2 Films on PET Substrate by ECR-MOCVD (반응가스조성이 PET기판위에 ECR 화학증착법에 의해 제조된 SnO2 박막특성에 미치는 영향)

  • Kim, Yun-Seok;Lee, Joong-Kee
    • Journal of the Korean Electrochemical Society
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    • v.8 no.3
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    • pp.139-145
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    • 2005
  • [ $SnO_x$ ] films on the flexible substrate of PET film were prepared at ambient temperature under a $(CH_3)_4Sn(TMT: tetra-methyl tin)-H_2-O_2$ atmosphere in order to obtain transparent conductive polymer by using ECR-MOCVD(Electro Cyclotron Resonance Metal Organic Chemical Yfpor Deposition) system. The prepared $SnO_x$ thin films show generally over $90\%$ of optical transmittance at wavelength range of 380-780nm and about $1\times10^{-2\~3}ohm{\cdot}cm$ of electrical resistivity. In the present study, effects of $O_2/TMT\;and\;H_2/TMT$ mole ratio on the properties of $SnO_x$ films are investigated and the other process parameters such as microwave power, magnetic current power, substrate distance and working pressure are fixed. Based on our experimental results, the $SnO_x$ film composition ratio of Sn and O directly influences on the electrical and optical properties of the films prepared. The $SnO_x$ film with low electric resistivity and high transmittance could be obtained by controlling the process parameters such as $O_2/TMT\;and\;H_2/TMT$ mole ratio, which play an important role to change the composition ratio between Sn and O. An increase of $O_2/TMT$ mole ratio brought on the increases 0 content in the $SnO_x$ film. On the other hand, an increase of $H_2/TMT$ mole ratio lead to decreases the oxygen content in the film. The optimized composition ratio of oxygen : tin Is determined as 2.4: 1 at $O_2/TMT$ of 80 and $H_2/TMT$ of 40 mole ratio, respectively.

Fabrication and Characteristics of a White Emission Electroluminicent Device (백색 전계발광소자의 제작과 그 특성)

  • Kim, Woo-Hyun;Choi, Sie-Young
    • Journal of Sensor Science and Technology
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    • v.10 no.6
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    • pp.295-303
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    • 2001
  • White emission thin film electroluminecent device was fabricated with ZnS for phosphor layers and BST ferroelectric thin film for insulating layers. The ZnS:Mn and $ZnS:SmF_3$ layers were used for emission of red color. Also the $ZnS:TbF_3$ and $ZnS:AgF_3$ layers were used to emission of green and blue color, respectively. And the fabrication conditions of the BST insulating layers were followings, that is, the composition ratio of target, substrate temperature, working pressure and operating gas ratio were $Ba_{0.5}Sr_{0.5}Ti_{0.3}$, $400^{\circ}C$, 30 mTorr and 9:1, respectively. The thickness of phosphor were 150 nm for each layers and the insulating layers of upper and bottom were 400 nm and 200 nm, respectively. The luminesence threshold voltage was $75\;V_{rms}$ and the maximum brightness of the thin film electroluminecent device was $3200\;cd/m^2$ at $100\;V_{rms}$.

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Properties of Foamed Concrete According to Types and Concentrations of Foam Agent (기포제 종류 및 희석 농도에 따른 기포 콘크리트의 특성)

  • Kim, Jin-Man;Jeong, Ji-Yong;Hwang, Eui-Hwan;Shin, Sang-Chul
    • Journal of the Korea Concrete Institute
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    • v.24 no.1
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    • pp.61-70
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    • 2012
  • Recently, the government has been working feverously to save energy and reduce greenhouse gas emission by enacting Basic Act on Low Carbon Green Growth at the national level. Improving the insulation performance of building exterior and insulator can reduce the energy in the building sector. This study is about developing light-weight foamed concrete insulation panel that can be applied to buildings to save energy and to find the optimal condition for the development of insulation materials that can save energy by enhancing its physical, kinetic and thermal characteristics. Various experimental factors and conditions were considered in the study such as foam agent types (AES=Alcohol Ethoxy Sulfate, AOS=Alpha-Olefin Sulfonate, VS=Vegetable Soap, FP=Fe-Protein), foam agent dilution concentration (1, 3, 5%), and foam percentage (30, 50, 70%). Experiment results indicated that the surface tension of aqueous solution including foam agent, was lower when AOS was used over other foam agents. FP produced relatively stable foams in 3% or more, which produced unstable foams containing high water content and low surface tension when diluted at low concentration. Depending on foam agent types, compressive strength and thermal conductivity were similar at low density range but showed some differences at high concentration range. In addition, when concentrations of foam agent and foaming ratio increased, pore size increased and open pores are formed. In all types of foam agent, thermal conductivity were excellent, satisfying KS standards. The most outstanding performance for insulation panel was obtained when FP 3% was used.

Measurement and analysis of tractor emission during plow tillage operation

  • Jun-Ho Lee;Hyeon-Ho Jeon;Seung-Min Baek;Seung-Yun Baek;Wan-Soo Kim;Yong-Joo Kim;Ryu-Gap Lim
    • Korean Journal of Agricultural Science
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    • v.50 no.3
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    • pp.383-394
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    • 2023
  • In Korea, the U.S. Tier-4 Final emission standards have been applied to agricultural machinery since 2015. This study was conducted to analyze the emission characteristics of agricultural tractors during plow tillage operations using PEMS (portable emissions measurement systems). The tractor working speed was set as M2 (5.95 km/h) and M3 (7.60 km/h), which was the most used gear stage during plow tillage operation. An engine idling test was conducted before the plow tillage operation was conducted because the level of emissions differed depending on the temperature of the engine (cold and hot states). The estimated level of emissions for the regular area (660 m2), which was the typical area of cultivation, was based on an implement width of 2.15 m and distance from the work area of 2.2 m. As a result, average emission of CO (carbon monoxide), THC (total hydrocarbons), NOx (nitric oxides), and PM (particulate matter) were approximately 6.17×10-2, 3.36×10-4, 2.01×10-4, and 6.85×10-6 g/s, respectively. Based on the regular area, the total emission of CO, THC, NOx, and PM was 2.62, 3.76×10-2, 1.63, and 2.59×10-4 g, respectively. The results of total emission during plow tillage were compared to Tier 4 emission regulation limits. Tier 4 emission regulation limits means maximum value of the emission per consumption power (g/kWh), calculated as ratio of the emission and consumption power. Therefore, the total emission was converted to the emission per power using the rated power of the tractor. The emission per power was found to be satisfied below Tier 4 emission regulation limits for each emission gas. It is necessary to measure data by applying various test modes in the future and utilize them to calculate emission because the emission depends on various variables such as measurement environment and test mode.

Wearable Computers

  • Cho, Gil-Soo;Barfield, Woodrow;Baird, Kevin
    • Fiber Technology and Industry
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    • v.2 no.4
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    • pp.490-508
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    • 1998
  • One of the latest fields of research in the area of output devices is tactual display devices [13,31]. These tactual or haptic devices allow the user to receive haptic feedback output from a variety of sources. This allows the user to actually feel virtual objects and manipulate them by touch. This is an emerging technology and will be instrumental in enhancing the realism of wearable augmented environments for certain applications. Tactual displays have previously been used for scientific visualization in virtual environments by chemists and engineers to improve perception and understanding of force fields and of world models populated with the impenetrable. In addition to tactual displays, the use of wearable audio displays that allow sound to be spatialized are being developed. With wearable computers, designers will soon be able to pair spatialized sound to virtual representations of objects when appropriate to make the wearable computer experience even more realistic to the user. Furthermore, as the number and complexity of wearable computing applications continues to grow, there will be increasing needs for systems that are faster, lighter, and have higher resolution displays. Better networking technology will also need to be developed to allow all users of wearable computers to have high bandwidth connections for real time information gathering and collaboration. In addition to the technology advances that make users need to wear computers in everyday life, there is also the desire to have users want to wear their computers. In order to do this, wearable computing needs to be unobtrusive and socially acceptable. By making wearables smaller and lighter, or actually embedding them in clothing, users can conceal them easily and wear them comfortably. The military is currently working on the development of the Personal Information Carrier (PIC) or digital dog tag. The PIC is a small electronic storage device containing medical information about the wearer. While old military dog tags contained only 5 lines of information, the digital tags may contain volumes of multi-media information including medical history, X-rays, and cardiograms. Using hand held devices in the field, medics would be able to call this information up in real time for better treatment. A fully functional transmittable device is still years off, but this technology once developed in the military, could be adapted tp civilian users and provide ant information, medical or otherwise, in a portable, not obstructive, and fashionable way. Another future device that could increase safety and well being of its users is the nose on-a-chip developed by the Oak Ridge National Lab in Tennessee. This tiny digital silicon chip about the size of a dime, is capable of 'smelling' natural gas leaks in stoves, heaters, and other appliances. It can also detect dangerous levels of carbon monoxide. This device can also be configured to notify the fire department when a leak is detected. This nose chip should be commercially available within 2 years, and is inexpensive, requires low power, and is very sensitive. Along with gas detection capabilities, this device may someday also be configured to detect smoke and other harmful gases. By embedding this chip into workers uniforms, name tags, etc., this could be a lifesaving computational accessory. In addition to the future safety technology soon to be available as accessories are devices that are for entertainment and security. The LCI computer group is developing a Smartpen, that electronically verifies a user's signature. With the increase in credit card use and the rise in forgeries, is the need for commercial industries to constantly verify signatures. This Smartpen writes like a normal pen but uses sensors to detect the motion of the pen as the user signs their name to authenticate the signature. This computational accessory should be available in 1999, and would bring increased peace of mind to consumers and vendors alike. In the entertainment domain, Panasonic is creating the first portable hand-held DVD player. This device weight less than 3 pounds and has a screen about 6' across. The color LCD has the same 16:9 aspect ratio of a cinema screen and supports a high resolution of 280,000 pixels and stereo sound. The player can play standard DVD movies and has a hour battery life for mobile use. To summarize, in this paper we presented concepts related to the design and use of wearable computers with extensions to smart spaces. For some time, researchers in telerobotics have used computer graphics to enhance remote scenes. Recent advances in augmented reality displays make it possible to enhance the user's local environment with 'information'. As shown in this paper, there are many application areas for this technology such as medicine, manufacturing, training, and recreation. Wearable computers allow a much closer association of information with the user. By embedding sensors in the wearable to allow it to see what the user sees, hear what the user hears, sense the user's physical state, and analyze what the user is typing, an intelligent agent may be able to analyze what the user is doing and try to predict the resources he will need next or in the near future. Using this information, the agent may download files, reserve communications bandwidth, post reminders, or automatically send updates to colleagues to help facilitate the user's daily interactions. This intelligent wearable computer would be able to act as a personal assistant, who is always around, knows the user's personal preferences and tastes, and tries to streamline interactions with the rest of the world.

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Performance Characteristics of Agitated Bed Manure Composting and Ammonia Removal from Composting Using Sawdust Biofiltration System (교반식 축분 퇴비화 및 톱밥 탈취처리 시스템의 퇴비화 암모니아 제거 성능)

  • Hong, J.H.;Park, K.J.
    • Journal of Animal Environmental Science
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    • v.13 no.1
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    • pp.13-20
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    • 2007
  • Sawdust biofiltration is an emerging bio-technology for control of ammonia emissions including compost odors from composting of biological wastes. Although sawdust is widely used as a medium for bulking agent in composting system and for microbial attachment in biofiltration systems, the performance of agitated bed composting and sawdust biofiltration are not well established. A pilot-scale composting of hog manure amended with sawdust and sawdust biofiltration systems for practical operation were investigated using aerated and agitated rectangular reactor with compost turner and sawdust biofilter operated under controlled conditions, each with a working capacity of approximately $40m^3\;and\;4.5m^3$ respectively. These were used to investigate the effect of compost temperature, seed germination rate and the C/N ratio of the compost on ammonia emissions, compost maturity and sawdust biofiltration performance. Temperature profiles showed that the material in three runs had been reached to temperature of 55 to $65^{\circ}C$ and above. The ammonia concentration in the exhaust gas of the sawdust biofilter media was below the maximum average value as 45 ppm. Seed germination rate levels of final compost was maintained from 70 to 93% and EC values of the finished compost varied between 2.8 and 4.8 ds/m, providing adequate conditions for plant growth.

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