• 분석과학
• /
• 제35권6호
• /
• pp.249-255
• /
• 2022

본 연구에서는 기체 크로마토그래피-불꽃이온화검출기(GC-FID)를 이용한 고순도 질소의 새로운 순도분석법을 개발하였다. 고순도 질소에 존재할 수 있는 불순물인 일산화탄소(CO), 이산화탄소(CO₂), 및 메탄(CH₄)에 대한 3 µmol/mol 수준의 인증표준물질(Certified reference material, CRM)을 중량법을 이용하여 제조하였고, 이를 순도분석에 활용하였다. 개발된 순도분석법에서는 운반가스로 초고순도 질소와 순도분석 대상 질소를 사용하여, 제조된 인증표준물질의 기체 크로마토그래피에서 얻어지는 크로마토그램의 면적 값 차이를 비교함으로써 순도분석 대상 질소의 불순물을 정량 분석하였다. 순도분석 대상 질소로는 액체질소 및 제조사가 각기 다른 3곳의 고순도 질소를 사용하였다. 또한, 개발된 순도분석법의 유효성을 평가하기 위하여 순도분석 대상 질소 내 불순물의 물질량 분율을 기존 순도분석법과 비교하였다. 두 가지 순도분석법을 이용하였을 때 대상 질소 내 불순물의 물질량 분율이 불확도 (k = 2) 내에서 서로 일치함을 확인함으로써, 개발된 순도분석법이 유효함을 확인하였다.

• 한국분말재료학회지
• /
• 제11권4호
• /
• pp.294-300
• /
• 2004

This study for preparation of aluminum nitride (AlN) with high purity was carried out by self-propagating high-temperature synthesis method in two different systems, $Al-N_{2}$ and $Al-N_{2}$-AlN, with the change of nitrogen gas pressure and dilution factor. On the occasion of $Al-N_{2}$ system, unreacted aluminum was detected in the product in spite of high nitrogen pressure, 10 MPa, This may be caused by obstructing nitrogen gas flow to inner part of molten and agglomerate of aluminum, formed in pre-heating zone. In $Al-N_{2}$-AlN system, AlN with a purity of 95% or ever can be prepared in the condition of $f_{Dil}\geq0.5$, $P_{N_{2}}\geq$ 1 MPa, and the purity can be elevated to 98% over in the condition of $f_{Dil}$ = 0.7 and $P_{N_{2}}$ = 10 MPa.

• 한국분말재료학회지
• /
• 제15권3호
• /
• pp.196-203
• /
• 2008

The densification behavior of Al-20Si-5.5Fe-1.2Mg-0.5Mn powders was investigated through micro-structure analysis of sintered specimens. The specimens sintered in vacuum or in high purity (99.999%) nitrogen showed porous near-surface microstructures. The densification of near-surface part was enhanced by means of ultra-high purity (99.9999%) nitrogen atmosphere. The relationship between slow densification and oxide surfaces of Al alloy powders was discussed. And the effects of Mg addition, nitrogen gas, and humidity on densification were discussed. In addition, the rapid growth of primary Si crystals above the critical temperature was reported.

• 공업화학
• /
• 제25권3호
• /
• pp.330-336
• /
• 2014

추출-증류-결정의 조합에 의해 모델 콜타르 흡수유 중에 함유된 인돌의 정제를 검토했다. 흡수유는 4종류의 질소고리 화합물(9.2% 퀴놀린, 2.4% 이소퀴놀린, 4.7% 인돌, 2.4% 퀴날딘), 3종류의 2환 방향족 화합물(14.2% 1-메틸나프탈렌, 31.8% 2-메틸나프탈렌, 23.5% 디메틸나프탈렌), 5.5% 비페닐과 3.3% 페닐에테르의 9종류의 화합물로 구성되어 있다. 포름아미드 추출-증류-노말헥산을 사용한 용액 결정화의 조합의 채택에 의해 99.5% 인돌을 회수할 수 있었다. 본 연구를 통해 얻어진 실험적 결과를 이용하여 콜타르 흡수유 중에 함유된 인돌의 회수공정을 검토했다.

• 대한환경공학회지
• /
• 제35권8호
• /
• pp.586-591
• /
• 2013

정제 질소가스 생산용 기체 분리막을 매립가스의 $CH_4$ 순도를 높이는데 활용하기 위한 연구를 수행하였다. 1단과 2단 분리막 모듈의 면적비는 1:6인 경우가 $CH_4$ 회수를 위해서 적절하였다. 분리막 장치 설치 후 총 249회에 걸쳐 실험을 하였으며, 투과율은 평균 $CH_4$ 28.4%, $CO_2$ 94.3%로서, 매립가스로부터 $CH_4$를 회수하는데 $N_2$ 분리막의 사용 가능성을 확인할 수 있었다. 다만, $N_2$ 투과율 역시 16.5%에 불과하였으며, 이에 따라 최종 정제된 LFG의 농도는 $CH_4$ 69.7%, $CO_2$ 4.3%, $N_2$ 26.0%이었다. 따라서 $CH_4$의 순도를 높이기 위해서는 매립장내 외기유입 억제를 통해 $N_2$ 농도를 적어도 2.0% 이내로 제한할 필요가 있었다.

• 한국산업융합학회 논문집
• /
• 제7권3호
• /
• pp.259-263
• /
• 2004

In the manufacture progress of LCD or semiconductor, there are used many kinds of gas like erosion gas, dilution gas, toxic gas as a progress which used these gas there are required high puritize to increase accumulation rate of semiconductor or LCD materials work progress of semiconductor or LCD it demand many things like the material which could minimize metallic dust that could be occured by reaction between gas and transfer pipe laying material, illumination of the surface, emition of the gas, metal liquation, welding etc also demand quality geting stricted. Material-Low-sulfur-contend (0.007-0010), vacuum-arc-remelt(VAR), seamless, high-purity tubing material is recommend for enhance welding lower surface defect density All wetted stainless steel surface must be 316LSS elecrto polishinged with ${\leq}0.254{\mu}m$($10.0{\mu}in$) Ra average surface finish, $Cr/Fe{\geq}1.1$ and $Cr_2O_3$ thickness ${\geq}25{\AA}$ From the AES analytical the oxide layer thickness (23.5~36 angstroms silicon dioxide equivalent) and chromum to iron ratios is similar to those generally found on electropolished stainless steel., molybdenum and silicon contaminants ; elements characteristic of stainless steel (iron, nickel and chromium); and oxygen were found on the surface Phosphorus and nitrogen are common contaminants from the electropolish and passivation steps.

• 자원리싸이클링
• /
• 제25권5호
• /
• pp.75-83
• /
• 2016

탄소환원질화법을 이용하여 질화알루미늄(Aluminum Nitride: AlN)을 제조하는 연구를 배치당 0.7 ~ 1.5 kg 규모로 규모 확대하여 수행하였다. 고품위 알루미나 분말과 탄소(carbon black)를 배합하여 흑연 도가니에 장입하고, 노내 진공도 $2.0{\times}10^{-1}Torr$에서 온도($1,550{\sim}1,750^{\circ}C$), 시간(0.5 ~ 4 hr), $N_2$유량($10{\sim}40{\ell}/min$)을 변화시키면서 AlN을 합성하였다. 실험결과 합성온도 $1,700{\sim}1,750^{\circ}C$, 합성시간 3시간, 질소유량 $40{\ell}/min$가 적정 조건이었다. 또한, 합성한 AlN에 잔존하는 탄소를 제거하기 위하여 관상로에서 온도 $650-750^{\circ}C$, 1 - 2시간 범위에서 탈탄을 시킨 결과, 알루미나와 탄소 몰배합비 1 : 3.2 로 합성한 시료를 대기 분위기에서 탈탄온도 $750^{\circ}C$, 관상로의 회전속도 1.5 rpm에서 2시간 탈탄하는 것이 적정조건이었다. 시험 제조한 AlN의 성분 분석 결과 C 함량 835 ppm, O 함량 0.77%으로서 순도 99% 이상의 고품위 제품을 제조할 수 있었다.

• 열처리공학회지
• /
• 제8권2호
• /
• pp.137-148
• /
• 1995

The nitridation kinetics of titanium powder were studied by isothermal and non-isothermal (dynamic) methods in high purity nitrogen under I atm pressure. For the comparison with nitridation, the oxidation kinetics of titanium powder were also studied in dry oxygen at I atm pressure. An automatic recording electrobalance was used to measure the weight gain as a function of time and temperature. For the reaction with nitrogen, the nitride was formed at over $700^{\circ}C$. The reaction with nitrogen followed the parabolic rate law, and the activation energy was calculated to be 31 kcal/mol in the isothermal method (above $900^{\circ}C$). The non-stoichiometric TiNx has been synthesized by the nitridation at a proper temperature and time, followed by the homogenizing treatment above $1100^{\circ}C$. In comparison with the stoichiometric $TiN_{1.0}$ and the non-stoichiometric TiNx ($TiN_{0.5}$ and $TiN_{0.65}$), the hot oxidation characteristics of the former is superior to that of the latter. However, both non-stoichiometric nitrides make little difference in the hot oxidation characteristics.

• Nuclear Engineering and Technology
• /
• 제38권5호
• /
• pp.423-426
• /
• 2006

A developed neutron activation analysis(NAA) and gamma-spectrometry were applied to improve the analytical sensitivity and precision of impurities in electronic-circuit raw materials. It is well known that soft errors in high precision electronic circuits can be induced by alpha particles emitted from naturally occurring radioactive impurities such as U and Th. As electronic circuits have recently become smaller in dimension and higher in density, these alpha-particle emitting radioactive impurities must be strictly controlled. Therefore, new NAA methods have been established using a HTS(Hydraulic Transfer System) irradiation facility and a background reduction method. For eliminating or stabilizing fluctuated background caused by Rn-222 and its progeny nuclides in air, a nitrogen purging system is used. Using the developed NAA and gamma-spectrometry, ultra trace amounts of U(0.1ng/g) and Th(0.01ng/g) in an alumina ball and high purity silica used for an epoxy molding compound (EMC) could be determined.

• 센서학회지
• /
• 제30권5호
• /
• pp.314-319
• /
• 2021

In this study, biomarkers were analyzed and segmented using tunable infrared gas sensors after performing the principal component analysis. The free spectral range of the device under test (DUT) was around 30 nm and DUT-5580 yielded the highest output voltage property among the others. The biomarkers (isoprophyl alcohol, ethanol, methanol, and acetone solutions) were sequentially mixed with deionized water and their mists were carried into the gas chamber using high-purity nitrogen gas. A total of 17 different mixed gases were tested with three tunable infrared gas sensors, namely DUT-3144, DUT-5580, and DUT-8010. DUT-8010 resolved the infrared absorption spectra of whole mixed gases. Based on the principal component analysis with each DUT and their combinations, each mixed gas and the trends in increasing gas concentration could be well analyzed when the contributions of the eigenvalues of the first and second were higher than 70% and 10%, respectively, and their sum was greater than 90%.