• 한국정밀공학회지
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• 제21권3호
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• pp.139-146
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• 2004

In this study, to achieve the optimal conditions for mechanical hyper-fine pattern fabrication process, deformation behavior of the materials during indentation scratch test was studied with numerical method by ABAQUS S/W. Brittle materials (Si, Pyrex glass 7740) were used as specimens, and forming conditions to reduce the elastic recovery and pile-up were proposed. The indenter was modeled as a rigid surface. Minimum mesh sizes of specimens are 1-l0nm. Variables of the nanoindentation scratch test analysis are scratching speed, scratching load, tip radius and tip geometry. The nano-indentation scratch tests were performed by using the Berkovich pyramidal diamond indenter. Comparison between the experimental data and numerical result demonstrated that the FEM approach can be a good model of the nanoindentation scratch test. The result of the investigation will be applied to the fabrication of the hyper-fine pattern.

• 한국표면공학회지
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• 제18권3호
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• pp.116-124
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• 1985

Chemical vapor deposition of $SnO_2$ on Pyrex glass substrate has been investigated using $SnCl_4$ and Oxygen at relatively low temperatures(300-500$^{\circ}C$). The critical flow rate, which delineated the surface reaction controlled region from the mass transfer controlled region, was increased with deposition temperature. The apparent activation energy obtained in surface reaction controlled region was about 6Kcal/mole. The results show that deposition rate, electrical conductivity and transmittance were affected mainly by partial pressure of $SnCl_4$, but little by partial pressure f oxygen. The % transmission of 5000A-thick $SnO_2$ film was about 90% in visible spectrum region and sheet resistance was varied in 0.1-10${\Omega}$ per square shaped portion of the outer surface of the oxide.

• 대한전자공학회논문지
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• 제23권5호
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• pp.706-711
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• 1986

The AgGa1-xInxSe2 films are deposited by a flash evaporation method onto pyrex glass substrates at temperatures between 5\ulcorner and 360\ulcorner. The single crystalline films which have X-ray diffraction peak of only (112) plane are preared at substrate temperature above 360\ulcorner. The prepared AgGa 1-xInxSe2 films are high photosensitive. The temperature coefficients of energy gap are found to be (-1.2~-4.0)x10**4 eV/K and (-3.1~-5.2)x10**-4 eV/K, and that of peak energy of spectral photoresponse curve are found to be (-1.1 ~ -3.0)x10**-4 eV/K(50K~100K) and (-2.4~-5.1)x10**-4 eV/K(100K~300K).

• 자원리싸이클링
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• 제25권6호
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• pp.73-81
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• 2016

지오폴리머는 메타카올린 혹은 석탄재와 같은 알루미노실리케이트 원료를 알칼리 활성화제와 반응시켜 제조된 비정질 무기 폴리머로서 포틀랜드 시멘트보다 우수한 내열성을 보인다. 지오폴리머의 고온 수축률은 $600^{\circ}C$까지는 0.5 %이하 ~ 3 %정도이며 용융되기 전까지 총 수축률은 5 ~ 7 %정도이다. 본 연구는 Si/Al비 1.5인 지오폴리머 페이스트에 탄소 나노 섬유, 탄화규소, 파이렉스 유리, 질석 및 ISO 표준사를 첨가하여 지오폴리머의 압축강도와 고온 수축에 미치는 효과를 알아보았다. 탄소 나노 섬유, 탄화규소, 파이렉스 유리와 질석이 첨가된 지오폴리머의 압축강도는 35 ~ 40 MPa범위로 유사하였다. ISO 표준사를 30 wt.% 첨가한 지오폴리머 모르타르의 평균 압축강도는 28 MPa로 가장 낮았다. ISO 표준사를 첨가하면 압축강도는 감소하였고 고온 수축률은 페이스트 수축률의 약 25 %까지 감소되었다. 이는 석영이 대부분인 잔골재 입자가 팽창하여 지오폴리머 겔 조직의 수축을 보상하였기 때문이다. 충전재의 종류와 관계없이 $900^{\circ}C$ 가열 후 지오폴리머 겔 조직은 소결현상에 의해 치밀해졌다.

• 한국대기환경학회지
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• 제22권2호
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• pp.259-266
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• 2006

A dual-channel glass coil sampling technique was used to measure hourly formaldehyde concentration in the ambient air. The dual-channel coil sampling assembly consists of three parts; an all-pyrex 28-turn coil made of 0.2-cm internal diameter glass tubing for gas-liquid contact and scrubbing of soluble gases, an inlet section upstream of the coil for introducing sample air and scrubbing solution, and a widened glass section downstream of the coil for gas-liquid separation. The scrubbing solution used was a dilute aqueous DNPH (dinitrophenylhydrazine) solution. Hourly concentration of formaldehyde was determined at a Gwangju semi-urban site during two intensive studies between September and October using the dual channel glass-coil/DNPH sampling technique and HPLC (High Performance Liquid Chromatography) analysis. The mean concentration was 1.7($0.4{\sim}4.7$) and 3.0($0.5{\sim}19.1$) ppbv for the September and October intensives, respectively, which are considerably low, compared to those measured in polluted urban areas around the world including several urban areas of Korea. The diurnal variation showed significant increase of formaldehyde in the daytime suggesting the dominance of formation of formaldehyde due to photochemical oxidation of methane and other hydrocarbons. An increase in the formaldehyde sometimes in the night might be due to an increase in primary source, i.e. traffic emissions. It was also found that rapid increase in formaldehyde levels from 3.0 to 19.1 ppbv in the afternoon on October 20 was due to plumes from burning of agricultural wastes such as rice straw and stubble. It is expected from the measurement data that the constructed dual-channel glass coil sampling system can be utilized for measuring atmospheric concentration of the formaldehyde with high time resolution.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1921-1923
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• 2001

In this work, an array of resistance temperature detector(RTD) was fabricated inside the microchannel in order to investigate in-situ flow characteristics. A rectangular straight microchannel, integrated with RTD's for temperature sensing and a heat source for generating the temperature gradient along the channel. were fabricated with the dimension of $200{\mu}m(W){\times}{\mu}m(D){\times}$48mm(L), while RTD measured precise temperatures at the inside-channel wall. 4" $525{\pm}25{\mu}m$ thick P-type <100> Si wafer was used as a substrate. For the fabrication of RTDs. 5300$\AA$ thick Pt/Ti layer was sputtered on a Pyrex glass wafer. Finally, glass wafer was bonded with Si wafer by anodic bonding, therefore RTD was located inside the microchannel. The temperature distribution inside the fabricated microchannel was obtained from 4 point probe measurements and Dl water is used as a working fluid. Temperature distribution inside the microchannel was measured as a function of mass flow rate and heat flux. As a result, precise temperatures inside the microchannel could be obtained. In conclusion, this novel temperature distribution measurement system will be very useful to the accurate analysis of the flow characteristics in the microchannel.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권9호
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• pp.449-454
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• 2002

A rectangular straight microchannel, integrated with the resistance temperature detectors(RTDs) for temperature sensing and a micro-heater for generating the Temperature gradient along the channel, was fabricated. Its dimension is 57${\mu}{\textrm}{m}$(H)$\times$200${\mu}{\textrm}{m}$(W)$\times$48,050${\mu}{\textrm}{m}$(L), and RTDs were placed at the inner-channel wall. Si wafer was used as a substrate. For the fabrication of RTDs, 5300$\AA$ thick Pt/Ti layer was sputtered on a Pyrex glass wafer. Finally, the glass wafer was bonded with Si wafer by anodic bonding, so that the RTDs are located inside the microchannel. Temperature coefficient of resistance(TCR) values of the fabricated Pt-RTDs were 2800~2950ppm$^{\circ}C$ and the variation of TCR value In the range of O~10$0^{\circ}C$ was less than 0.3％. Therefore, it was proved that the fabricated Pt-RTDs without annealing were excellent as temperature sensors. The temperature distribution in the microchannel was investigated as a function of mass flow rate and heating power. The temperature increase rate diminished with decreasing the applied power and increasing the mass flow rate. It was confirmed from the comparison with the simulation results that the temperature measured inside the microchannel is more accurate than measuring the temperature measured at the outer wall. The proposed temperature sensing method and microchannel are expected to be useful in microfluidics researches.

• 한국전기전자재료학회논문지
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• 제33권5호
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• pp.367-372
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• 2020

As packaging processes for atomic gyroscope vapor cells, the glass tube tip-off process, anodic bonding, and paste sealing have been widely studied. However, there are stability issues in the alkali metal which are caused by impurity elements and leakage during high-temperature processes. In this study, we investigated the applicability of a vapor cell low-temperature packaging process by depositing Au on a Pyrex cell in addition to forming an Au-Sn thin film on a cap to cover the cell, followed by laser irradiation of the Au/Au-Sn interface. The mechanism of the thin film bonding was evaluated by XRD, while the packaging reliability of an Ne gas-filled vapor cell was characterized by variation of plasma discharge behavior with time. Furthermore, we confirmed that the Rb alkaline metal inside the vapor cell showed no color change, indicating no oxidation occurred during the process.

• 대한기계학회논문집A
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• 제28권9호
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• pp.1429-1434
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• 2004

Immunoassay is one of the important analytical methods for clinical diagnoses and biochemical studies, but needs a long time, troublesome procedures and expensive reagents. In this study, therefore, we propose the micro filter chip with microbeads for immunoassay, which has pillar structures. The advantage of the proposed micro filter chip is to use simple fabrication process and cheap materials. The mold was made by the photolithography technique with Si wafer and negative photoresist SU-8. The replica was made of PDMS, bonded on the pyrex glass. The micro filter chip consists of inlet channel, filter chamber and outlet channel. HBV (Hepatitius B virus) monoclonal antibody (Ag1) labeled with biotin were immobilized onto streptavidin coated beads of 30∼50 $\mu$m size. Fluorescein isothiocyanate (FITC)-labeled HBV monoclonal antibody (Ag8) was used to detect HBsAg (Hebatitis B virus surface Antigen), and fluorescence intensity was monitored by epi-fluorescence microscope. In this study, the immune response of less than 30 min was obtained with with the use of 100 $m\ell$ of sample.

• 한국환경과학회지
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• 제15권9호
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• pp.855-864
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• 2006

This study introduces a method to eliminate formaldehyde and benzene, toluene from indoor air by means of a photocatalytic oxidation reaction. In the method introduced, for the good performance of the reaction, the effect and interactions of the $TiO_2$ catalyst and ultraviolet in photocatalytic degradation on the reaction area, dosages of catalysts, humidity and light should be precisely examined and controled. Experiments has been carried out under various intensities of UV light and initial concentrations of formaldehyde, benzene and toluene to investigate the removal efficiency of the pollutants. Reactors in the experiments consist of an annular type Pyrex glass flow reactor and an 11W germicidal lamp. Results of the experiments showed reduction of formaldehyde, benzene and toluene in ultraviolet $/TiO_2/$ activated carbon processes (photooxidation-photocatalytic oxidation-adsorption processes), from 98% to 90%, from 98% to 93% and from 99% to 97% respectively. Form the results we can get a conclusion that a ultraviolet/Tio2/activated carbon system used in the method introduced is a powerful one for th treatment of formaldehyde, benzene and toluene of indoor spaces.