• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.361-372
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• 2023

Organotin pesticide is used as an acaricide in agriculture and may contaminate livestock products. This study aims to develop a rapid and straightforward analytical method for detecting organotin pesticides, specifically azocyclotin, cyhexatin, and fenbutatin oxide, in various livestock products, including beef, pork, chicken, egg, and milk, using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The extraction process involved the use of 1% acetic acid in a mixture of acetonitrile and ethyl acetate (1:1). This was followed by the addition of anhydrous magnesium sulfate (MgSO₄) and anhydrous sodium chloride. The extracts were subsequently purified using octadecyl (C₁₈) and primary secondary amine (PSA), after which the supernatant was evaporated. Organotin pesticide recovery ranged from 75.7 to 115.3%, with a coefficient of variation (CV) below 25.3%. The results meet the criteria range of the Codex guidelines (CODEX CAC/GL 40). The analytical method in this study will be invaluable for the analysis of organotin pesticides in livestock products.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.278-295
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• 2014

Fast and accurate multi-residue pesticides inspecting method needs in Agro-Fishery Products Inspection Center. So, We tried to seek the optimum method using GC-TOF/MS, GC-ECD, GC-NPD after QuEChERS sample preparation. In GC-TOF/MS, 138 kinds of pesticide were spiked at 0.3 and $0.5{\mu}g/g$for the identification and quantification in lettuce sample. Recoveries of 77 pesticides were between 70 and 130% with RSD (relative standard deviation lower than 20% at $0.3{\mu}g/g$. In GC-ECD, NPD, 146 kinds of pesticide were spiked for the identification and quantification in lettuce. Recoveries of 61 species were between 70 and 130% with lower than 20%. These results indicated that GC-TOF/MS, GC-ECD, NPD analysis with the QuEChERS sample preparation can be partly applied to multi-residue pesticides in vegetables.

• Korean Journal of Materials Research
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• v.8 no.7
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• pp.634-640
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• 1998

A well- shaped trench was investigated in view of the defect distribution along trench sidewall and bottom using high resolution transmission electron microscopy. The trench was formed by HBr plasma and additive gases in magnetically enhanced reactive ion etching system. Adding $0_2$ and other additive gases into HBr plasma makes it possible to eliminate sidewall undercut and lower surface roughness by forming the passivation layer of lateral etching, resulted in the well filled trench with oxide and polysilicon by subsequent deposition. The passivation layer of lateral etching was mainly composed of $SiO_xF_y$ $SiO_xBr_y$ confirmed by chemical analysis. It also affects the generation and distribution of lattice defects. Most of etch induced defects were found in the edge region of the trench bottom within the depth of 10$\AA$. They are generally decreased with the thickness of residue layer and almost disappeared below the uni¬formly thick residue layer. While the formation of crystalline defects in silicon substrate mainly depends on the incident angle and energy of etch species, the region of surface defects on the thickness of residue layer formed during trench etching.

• Resources Recycling
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• v.8 no.5
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• pp.34-43
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• 1999

An elecmc arc cracking reaclor is developed for the productiol~o f ieusuble fuel gas by the thennal destruction of waste oil. The churaclensucs of product gas and ~esiduesf rom arc crachng of wnste lubr~cat~nogil are sludird. Thc product gas is mainly coruposcd of hydrogen 135-4076), acetylene (13-4076), ethylene 13-476) and olher hgdrocnrbons. The contenr of carbon monomde, one or the main product in a conventional low-temperature Lhennal cracking umt, 1s very slnvll in lhis atc cracking expcnmcnt. Total calocctic wlue of product gas shows 11,000-13.000 kcizlkg, which is hiph cnough to use as a ~ L I I I Cga~ s . and the concentralions oC loxic gases arc well below the rcguliltury emission critena The GCIMS analysis of llquld-phase residues shows that the high rnalccular welgllt hydrocilrbons in the waste oil arc cracked into the low malecular weight hydrocarbons snd hydroem,. The dehydrogcnntion is found lo be Lhe main cracking rcacuon due lo the high temperalure ~ ~ ~ d ubcyc edle ctric arc. The average parucle size of soot as the solid-phase residue is 10 3 wm, and the conlents of cabon a ~ hdea vy metals are abovc 60% and under 0.01 ppm, respecttrely. Thc utllizvtion or sool, as industl-id1 rcsource seems lo he reasible aIter refimng.

• Journal of the Korean Institute of Gas
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• v.22 no.3
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• pp.45-52
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• 2018

As guidelines for exhaust gases of ship are reinforced by the International Maritime Organization, the necessity for LNG fuelled ship is emerging. The relevant research is actively progressing to develop technologies and promote commercialization. When the residual quantity of LNG fuel tank is less than 70% by consuming fuel during operation, sloshing should be considered. We applied the Type C LNG fuel tank because medium sized LNG fuelled ships are difficult to equip with re-liquefaction system. Structural integrity and thermal performance are very important, especially in LNG fuel tanks that apply to LNG fuelled ship. Through this study, we proposed evaluation procedure of thermal performance for the Type C LNG tank, and verified the validity and effectiveness of BOR(Boil-Off Rate) test Procedure by comparing and analyzing changes in temperature, pressure, BOG(Boil-Off Gas).

• Korean Journal of Materials Research
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• v.10 no.5
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• pp.328-334
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• 2000

The photocatalyst of $TiO_2$coated on glass bead was prepared from sol-gel method to remove the VOC (vola-tile organic compounds) by the photocatalytic reaction. The coated films were characterized by X-ray diffraction(XRD), specific surface area(BET), and scanning electron microscopy observation (SEM), The gas-phase photocatalytic degradation of trichloroethylene(TCE) and benzene with coated titanium dioxide on glass beads was in-vestigated using a fixed bed reactor. The degradation was calculated by the concentration difference with the retained on the reactor with aid of gas chromatography. At steady state, conversion yields were obtained for 80% of trichloroeth-vlene in 400 ppmv concentration and 65% on benzene in the range of concentration from 50 to 300 ppmv, respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.50-53
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• 2006

Regional geophysical surveys and geological cal studies on natural gas hydrate (NGH) in the East Sea were carried out by the Korea Institute of Geoscience and Mineral Resources (KIGAM) from 2000 to 2004. 16 piston cores, 2270 L-km of multi-channel reflection seismic (MCRS) data and 730 L-km of 3.5kHz Chirp data obtained from the southwestern part of the deep-water Ulleung Basin were analyzed in this study. In piston cores, cracks generally developed parallel to bedding suggest significant gas content. The core analyses showed high total organic carbon (TOC) content, sedimentation rate and heat flow of sediments. These are in favor of the general ion of substantial biogenic methane, which can form the NGH within the stability zone of the near seafloor sediments in the study area. The cores generally show also high residual hydrocarbon gas concentrations for the formation of natural gas hydrates The geophysical indicators of the presence of gas and/or NGH such as bottom simulating reflectors (BSRs), seismic blank Bones, pockmarks and gas seeping features were well defined on the MCRS and Chirp data.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.58.2-58.2
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• 2010

FPD (Flat Panel Display) 제조 공정에서 사용되는 패턴은 수 ${\mu}m$ 수준까지 감소하였으며, FPD의 크기는 급격하게 대형화 되여 현재 8세대(2200mm*2500mm)에 이르고 있다. 이에 따라, $1\;{\mu}m$ 이상의 크기를 갖는 오염입자에 의한 수율 저하를 극복하기 위한 세정효율의 향상 및 다량의 초순수 사용에 따른 폐수 발생으로 인한 환경오염, 또한 장비의 크기에 따른 공간 효용성 감소와 이에 따른 공정 비용의 증가 등의 어려움에 직면하고 있다. 따라서, 현장에서는 고효율, 저비용의 세정 공정 기술 개발에 대한 연구가 활발히 진행되고 있다. 이러한 문제점들을 해결 하고자 이류체 노즐 세정 장치와, 화학액 린스를 위한 초순수 Spray, 건조 공정에 해당하는 Air-knife, Halogen lamp로 구성된 소형화 된 고속 FPD(Flat Panel Display) 세정기에 대한 연구를 진행 하였다. 이류체 노즐은 초순수와 $N_2$ 가스를 내부에서 혼합하여 액적(Droplet)을 형성하여 고압으로 분사시키는 장치로서 화학액을 사용하지 않고 물리적인 방법으로 오염입자를 제거한다. Spray는 유기 오염입자 제거를 위한 오존수의 린스 공정을 위해 설치 하였다. 세정 후 표면에 남아있는 기판의 액막(water film)은 고압의 가스를 분사하는 Air-knife를 통해 제거하였으며, 고속 공정시 발생할 수 있는 Air-knife에서 제거하지 못한 잔류 액막을 Halogen lamp를 사용하여 효과적으로 제거함으로써, 물반점(water mark) 없는 건조 공정을 얻을 수 있었다. 실험에는 미세 입자의 정량적인 측정을 위하여 유리 기판 대신에 6인치 실리콘 웨이퍼(P-type (100))를 사용하였으며, > $\;1{\mu}m$ 실리카 입자를 스핀방식을 사용하여 정량적으로 균일하게 오염하였으며, 오염물의 개수 및 분포는 파티클 스캐너 (Surfscan 6200, KLA-Tancor, USA)를 사용하여 분포 및 개수를 정량적으로 측정 하였다. 이류체 노즐은 $N_2$ 가스의 압력과 초순수의 압력을 변화시켜 측정하여, 각각 0.20 MPa, 0.01 MPa에서 최적의 세정 결과를 얻을 수 있었으며, 건조 효율은 Air-Knife의 입사 각도와 건조면 간격, 할로겐 램프의 온도를 조절 하여 최적의 조건을 얻을 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.159-159
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• 2010

펄스 직류 전원 $BCl_3$/He 플라즈마를 사용하여 GaAs의 건식 식각을 연구하였다. 공정 변수는 가스 유량 (0~100% $BCl_3$ in $BCl_3$/He), 펄스 파워 ($450{\sim}600\;{\nu}$), 펄스 주파수 (100~250 KHz), 펄스 시간 ($0.4{\sim}1.2\;{\mu}s$)이었다. 식각 공정 후 식각률, 포토레지스트에 대한 식각 선택도, 표면 거칠기는 표면 단차 측정기를 이용하였다. 식각 공정 동안 플라즈마 광 특성 분석은 광학 발광분석기 (Optical emission spectroscopy)를 사용하였다. 실험 후 주사 전자 현미경을 이용, 식각 후 시료의 단면과 표면을 관찰하였다. 실험 결과에 의하면 1) 펄스 파워, 주파수, 시간을 고정 ($500\;{\nu}$, $0.7\;{\mu}s$, 200 KHz)하고 10% He 가스가 혼합되어 있는 조건에서 GaAs의 식각률이 순수한 $BCl_3$를 사용한 것보다 높았다. 이를 통해 식각 공정에서 일정량 이하의 He 혼합은 GaAs 식각률을 증가시키는 시너지효과가 있음을 알 수 있었다. 2) 그러나 약 20% 이상의 He 가스의 혼합은 GaAs의 식각 속도를 저하시켰다. 3) 10% He (9 sccm $BCl_3/1$ sccm He), 200 KHz 펄스 주파수, $0.7\;{\mu}s$ 펄스 시간의 조건에서 펄스 파워가 증가함에 따라 GaAs의 식각률 또한 선형적으로 증가하였다. 4) 특히, $600\;{\nu}$의 파워에서 식각률은 ${\sim}0.5\;{\mu}m/min$로 가장 높았다. 5) 표면 단차 측정기와 전자현미경을 이용하여 식각한 GaAs를 분석한 결과 10% He이 혼합되어 있는 조건에서는 우수한 수직 측벽과 매끈한 표면 (RMS roughness <1 nm)을 관찰할 수 있었다. 6) 10% He이 혼합된 $BCl_3$/He 펄스 직류 플라즈마 식각 후 XPS 분석결과에서도 기준 샘플과 비교하였을 때, 공정 후의 GaAs 표면이 화학적으로 깨끗하며 잔류물이 거의 검출되지 않았다. 위의 결과를 정리하였을 때, 펄스 직류 $BCl_3$/He 플라즈마는 GaAs의 식각에서 매우 우수한 공정 결과를 나타내었다.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.485-490
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• 2011

Tetrafluoromethane($CF_4$) has been used as etching and chamber cleaning gases for semiconductor manufacturing processes. These gases need to be removed efficiently because of their strong absorption of infrared radiation and long atmospheric lifetime which causes the global warming effect. We have developed a waterjet gliding arc plasma system in which plasma is combined with waterjet and investigated optimum operating conditions for efficient $CF_4$ destruction through enlarging discharge region and producing large amount of OH radicals. The operating conditions are waterjet flow rate, initial $CF_4$ concentration, total gas flow rate, specific energy input. Through the parametric studies, the highest $CF_4$ destruction of 97% was achieved at 2.2% $CF_4$, 7.2 kJ/L SEI, 9 L/min total gas flow rate and 25.5 mL/min waterjet flow rate.