• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.109-115
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• 2000

This study was designed to evaluate the microhardness of restorative composite resin and dual-cured composite resin cement which were light cured through the 1.5mm thickness composite overlay. For restorative materials, Z100 and Tetric Ceram were used. For dual cured composite cements, Variolink II((VL II) of three consistency (low, high, ultra high) were used. To determine the optimal microhardness of Z100, Tetric Ceram and Variolink II, each material was packed into the 1mm thickness teflon mold without composite overlay and light cured for 60 seconds. Then the microhardnesses of each sample were measured, averaged and regarded as optimal hardness of each material. To evaluate the microhardness of restorative composite resin and dual-cured composite resin cement which were light cured through the 1.5mm thickness composite overlay, the composites were packed into 1mm thickness teflon mold, coverd with celluloid strip, and then precured composite overlay which was made of Targis(Ivoclar/Vivadent, Liechtenstein) was positioned. 2 types of visible light curing machine, the power density of one of which was 400$mW/cm^2$ and the other was 900$mW/cm^2$, and one type of argon laser were used to cure the restorative composite and dual cured cement. For each group, 10 sample were assigned. The light curing tip was positioned over the composite overlay and light cured for 1min., 2min. or 3min with visible light curing machine or 15sec, 30 sec, 45sec, and 60 sec with argon laser. The Vickers hardnesses of upper and lower surface of Z100, Tetric Ceram, and 3 types of VL II cement were measured. When the 900 $mW/cm^2$ curing light was used, 2min. was needed for optimal curing of Z100 and Tetric Ceram. Variolink II did not be cured optimally even though the curing time was extended to 3min. When 400$mW/cm^2$ curing light was used, 3min. was necessary for Z100, whereas 3min. was not enough for Tetric Ceram. Variolink II was not cured optimally even though the curing time was extended to 3min. When argon laser was used, Z100, Tetric Ceram and Variolink II were not cured optimally in 60 seconds.

• Radiation Oncology Journal
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• v.19 no.3
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• pp.293-299
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• 2001

Prupose : LiF TLD has a problem to be used in vivo dosimetry because of the toxic property of LiF. The aim of this study is to develop new dosimeter with LiF TLD to be used in vivo dosimetry. Materials and methods : We designed and manufactured the teflon box(here after TLD holder) to put TLD in. The external size of TLD holder is $4\times4\times1\;mm^3$ To estimate the effect of TLD holder on TLD response for radiation, the linearity of TLD response to nominal dose were measured for TLD in TLD holder. Measurement were peformed in the 10 MV x-ray beam with LiF TLD using a solid water phantom at SSD of 100 cm. Percent Depth Dose (PDD) and Tissue-Maximum Ratio (TMR) with varying phantom thickness on TLD were measured to find the effect of TLD holder on the dose coefficient used for dose calculation in radiation therapy. Results : The linearity of response of TLD in TLD holder to the nominal dose was improved than TLD only used as dosimeter And in various measurement conditions, it makes a marginnal difference between TLD in TLD holder and TLD only in their responses. Conclusion : It was proven that the TLD in TLD holder as a new dosimetry could be used in vivo dosimetry.

• Journal of Chest Surgery
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• v.13 no.4
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• pp.455-461
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• 1980

This is one case report of surgically treated ventricular septal defect [VSD] with aortic insufficiency [AI] at department of thoracic and cardiovascular surgery, Hanyang university hospital. He had had progressive dyspnea on exertion and palpitation for 3 years prior to admission to our hospital. On examination, the blood pressure was 120/0 mmHg and the pulse rate 88 times/min. Bobbing motion of the head, Water hammer pulse, Corringan`s pulse, Quincke`s pulse and to and fro murmur were present. The heart murmur was consistent with .VSD and AI. Cardiomegaly was seen in chest X-ray. EKG, echocardiogram, aortogram and right heart catheterization was performed. On Sep. 9, 1980, open heart surgery was performed under the impression of VSD with AI. Infracrystal type VSD measuring 2 x 1.5 cm in diameter was closed with Teflon patch graft through the transverse ventriculotomy. AI was due to prolapsed, elongated right coronary and noncoronary cusp, especially noncoronary cusp. The prolapsed, elongated aortic leaflets were plicated by placing three 8-figure sutures between the free edge and the base of the leaflet [Frater`s method] through a transverse aortotomy. Postoperatively, he made an uneventful recovery, his blood pressure was 120/70 mmHg and showed no signs AI or residual shunt at discharge.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.7
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• pp.41-46
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• 2010

With the improvement of industrial society, high quality electrical energy, simplification of operation and maintenance, and ensuring reliability are being required. Also we request an urgent change from $SF_6$ gas to an environment-friendly gas insulation material. In this paper, the experiments of breakdown characteristics by pressure and gap change of $N_2/O_2$ mixture gas through a GIS (Gas Insulated Switchgear) model were described. This paper reviews basic data of the surface discharge characteristics for Teflon resin in not only pure $N_2$, $N_2:O_2$ mixture gas as being focused on environmentally-friendly insulating gas, but also $SF_6$. Also, insulation characteristics by breakdown voltage and surface discharge voltage of $N_2:O_2$ mixture gas in the experimental chamber were studied.

• Journal of the Korean Chemical Society
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• v.37 no.9
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• pp.800-805
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• 1993

An analytical method has been developed to determine trace elements in biological samples. The biological samples are added to a laboratory-bulit Teflon bomb together with nitric acid-hydrogen peroxide mixture and enriched stable isotopes. The samples are decomposed in a microwave oven. The decomposed sample solutions are analyzed by isotope dilution inductively coupled plasma mass spectrometry. The analytical results of the biological samples agree well with the reference values.

• Fire Science and Engineering
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• v.27 no.2
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• pp.70-74
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• 2013

It is very important for the collected samples at fire scenes to be properly preserved for laboratory analysis. Preserving abilities of four type containers, metal cans, glass jars, zipper and heat sealed polymer bags, with the five ignitable liquids (toluene, n-octane, o-xylene, n-decane and n-hexadecane) were examined with gas chromatography-mass spectrometry. The glass jars with Teflon (PTFE) liner were the best ability to prevent the evaporation of the ignitable liquids.

• Smart Structures and Systems
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• v.8 no.4
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• pp.399-412
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• 2011

This study compares the performance of two smart isolation systems that utilize superelastic shape memory alloys (SMAs) for seismic protection of bridges using energy balance concepts. The first isolation system is a SMA/rubber-based isolation system (SRB-IS) and consists of a laminated rubber bearing that decouples the superstructure from the bridge piers and a SMA device that provides additional energy dissipation and re-centering capacity. The second isolation system, named as superelastic-friction base isolator (S-FBI), combines the superelastic SMAs with a flat steel-Teflon bearing rather than a laminated rubber bearing. Seismic energy equations of a bridge structure with SMA-based isolation systems are established by absolute and relative energy balance formulations. Nonlinear time history analyses are performed in order to assess the effectiveness of the isolation systems and to compare their performance. The program RSPMatch 2005 is employed to generate spectrum compatible ground motions that are used in time history analyses of the isolated bridge. Results indicate that SRB-IS produces higher seismic input energy, recoverable energy and base shears as compared to the S-FBI system. Also, it is shown that combining superelastic SMAs with a sliding bearing rather than rubber bearing significantly reduce the amount of the required SMA material.

• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.3
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• pp.13-18
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• 1982

This Paper is an experimental study on the effective dielectric constant of microstrip line. To quantify the dispersive effects on a microstrip line, the effective dielectric constant, which is the ratio of free space wavelength to guide wavelength, is calculated for teflon substrates. The calculation is based on the Fourier transform of the current distribution on microstrip line. Measurements of effective dielectric constant using a microstrip elliptic resonator and ring resonator are also described. As a result, the computed values of effective dielectric constant agree almost all with measured values, using ring and elliptic resonator, in case of w/h or the ratio of microstrip width to substrate thickness equal unity over frequency range of 8 to 12GHz.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.2
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• pp.93-101
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• 2016

This paper presents the surface discharge characteristics in Dry-Air on laminated epoxy solid dielectrics and conductive particles in order to provide the valuable information for the insulation design of eco- friendly gas insulated switchgear. To improve insulation performance, the three types of the laminated epoxy solid dielectrics were proposed, and it was revealed that their surface discharge characteristics were similar to the bakelite dielectrics of same-laminated types. From the surface discharge characteristics of dry air, it was demonstrated that the effect of conductive particles on surface discharge voltage was dominant when there are this particles at the shortest electrode gap and that the degradation of insulation performance on the conductive particles was evident in epoxy than teflon. These phenomena were interpreted in terms of particle-triggered discharge mechanism and electric field of triple junction, respectively.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.5
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• pp.95-100
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• 2009

The water purification systems have been hardly used for agricultural purpose due to their complicated compositions and high costs for farmers, while only simple filtrations have been applied to irrigation systems in order to prevent the system from clogging problems. This study therefore developed a clean water supplying system, the Filter-Disinfection-Adsorption (FDA) system, especially for greenhouse cultivation of where low quality of water is available. This system has also been produced for providing convenience water to farmers in the areas of no water supply service systems for the purpose of washing their bodies or agricultural machineries after farm work. The FDA system consists of three stages of purification processes with an integral module, including disk and teflon filtrations and Ultraviolet (UV) sterilization processes. Indoor experiments were undertaken with a trial product of the FDA system to test its performance. The operation test of the process was performed as well as the condition check of each item including UV module, filters, control panel, pump, valves, etc. The results shows good performance of each test with no critical problems. The initial and maintenance costs were also analysed with other purification systems. From the comparisons, the FDA system found to be very economical and easy to use.