• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2005년도 학술발표대회 논문집
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• pp.385-392
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• 2005

The restriction of the use of hazardous substances in electrical and electronic equipment legislation mandates the substitution of lead and other hazardous substances in electronics products by July 2006. Due to this legislative pressure, the electronics industry is moving to adoption of lead free solders. In this paper, we investigated a flux to restrict generating electrochemical migration in lead-free solder. The lead-free solders used in this study were Sn-0.7Cu-0.01P and Sn-3.0Ag-0.5Cu. To measure the resistance of electrochemical migration, the dew-cycle test and water drop test were adopted. As the result, now flux having high durable of electrochemical migration was developed.

• Korean Chemical Engineering Research
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• 제52권2호
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• pp.272-277
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• 2014

본 연구는 인쇄회로기판(PCB) 제조 시 에칭공정에서 발생되는 구리이온($Cu^{+2}$)을 고농도로 함유한 황산 폐에칭액을 NF 막분리법을 사용하여 에칭액 회수와 구리이온 처리를 효율적으로 수행하기 위한 NF 막여과 공정의 운전조건을 설정하기 위한 기본 자료를 확보하는데 있다. 이를 위해 미국 Koch사의 SelRO MPS-34 4040 NF 막을 대상으로 구리이온을 고농도(5~30 g/L)로 함유한 모의 황산 폐에칭액의 cross-flow 나노여과 실험을 수행하여 투과 플럭스와 구리이온의 총괄 배제도를 측정하였다. 이 결과 투과 플럭스는 황산 폐에칭액 내 구리이온의 농도가 증가할수록, 황산 폐에칭액의 pH가 낮을수록 작아졌으며, 그 값은 최소 $4.5L/m^2{\cdot}h$에서 최대 $23L/m^2{\cdot}h$이었다. 황산 폐에칭액 내 구리이온의 총 배제도는 구리이온의 농도가 클수록, 용액의 pH가 낮을수록 그리고 폐에칭액의 순환유량이 작을수록 낮아졌으며, 황산 폐에칭액의 pH가 1 이상인 상태에서 70% 이상의 구리이온 배제가 가능하였다. NF 막을 12개월 동안 황산용액 내에 보관하여도 투과 플러스 와 구리이온 배제도의 유의한 변화가 없어 SelRO MPS-34 막모듈을 강산 조건에서 1년이상 막모듈의 교체 없이 산성 폐에칭액 처리에의 사용이 가능하였다.

• 멤브레인
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• 제23권1호
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• pp.92-99
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• 2013

본 연구는 인쇄회로기판(PCB) 제조 시 에칭공정에서 발생되는 구리이온($Cu^{+2}$)을 고농도로 함유한 황산 폐에칭액을 NF 막분리법을 사용하여 에칭액 회수와 구리이온 처리를 효율적으로 수행하기 위한 NF 막여과 공정의 운전 조건을 설정하기 위한 기본 자료를 확보하는데 있다. 이를 위해 미국 Koch사의 SelRO MPS-34 4040 NF 막을 대상으로 구리이온을 고농도(5~25 g/L)로 함유한 모의 황산 폐에칭액의 회분식(dead-end) 나노여과 실험을 수행하여 투과 플럭스와 구리이온의 총괄 배제도를 측정하였다. 이 결과 황산용액에의 막 보관기간이 길수록, 황산용액의 pH가 낮을수록 황산에 의한 NF 막의 손상이 더 크게 발생하여 순수 투과 플러스가 증가하였다. 황산 폐에칭액의 투과 플럭스는 황산용액 내 구리이온의 농도가 증가할수록 막 표면에의 구리이온 농축(농도분극)의 증가에 따라 감소하였으며, 구리이온의 배제도는 구리이온의 농도가 높을수록, pH가 낮을수록, 황산용액 내의 막 보관기간이 길수록 낮아져 초기 37%에서 최소 15% 수준으로까지 감소하였다.

• 상하수도학회지
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• 제35권1호
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• pp.93-100
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• 2021

Forward osmosis (FO) process is a chemical potential driven process, where highly concentrated draw solution (DS) is used to take water through semi-permeable membrane from feed solution (FS) with lower concentration. Recently, commercial FO membrane modules have been developed so that full-scale FO process can be applied to seawater desalination or water reuse. In order to design a real-scale FO plant, the performance prediction of FO membrane modules installed in the plant is essential. Especially, the flux prediction is the most important task because the amount of diluted draw solution and concentrate solution flowing out of FO modules can be expected from the flux. Through a previous study, a theoretical based FO module model to predict flux was developed. However it needs an intensive numerical calculation work and a fitting process to reflect a complex module geometry. The idea of this work is to introduce deep learning to predict flux of FO membrane modules using 116 experimental data set, which include six input variables (flow rate, pressure, and ion concentration of DS and FS) and one output variable (flux). The procedure of optimizing a deep learning model to minimize prediction error and overfitting problem was developed and tested. The optimized deep learning model (error of 3.87%) was found to predict flux better than the theoretical based FO module model (error of 10.13%) in the data set which were not used in machine learning.

• ALGAE
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• 제36권4호
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• pp.315-326
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• 2021

Ion channels are membrane protein complexes mediating passive ion flux across the cell membranes. Every organism has a certain set of ion channels that define its physiology. Dinoflagellates are ecologically important microorganisms characterized by effective physiological adaptability, which backs up their massive proliferations that often result in harmful blooms (red tides). In this study, we used a bioinformatics approach to identify homologs of known ion channels that belong to 36 ion channel families. We demonstrated that the versatility of the dinoflagellate physiology is underpinned by a high diversity of ion channels including homologs of animal and plant proteins, as well as channels unique to protists. The analysis of 27 transcriptomes allowed reconstructing a consensus ion channel repertoire (channelome) of dinoflagellates including the members of 31 ion channel families: inwardly-rectifying potassium channels, two-pore domain potassium channels, voltage-gated potassium channels (K_v), tandem K_v, cyclic nucleotide-binding domain-containing channels (CNBD), tandem CNBD, eukaryotic ionotropic glutamate receptors, large-conductance calcium-activated potassium channels, intermediate/small-conductance calcium-activated potassium channels, eukaryotic single-domain voltage-gated cation channels, transient receptor potential channels, two-pore domain calcium channels, four-domain voltage-gated cation channels, cation and anion Cys-loop receptors, small-conductivity mechanosensitive channels, large-conductivity mechanosensitive channels, voltage-gated proton channels, inositole-1,4,5-trisphosphate receptors, slow anion channels, aluminum-activated malate transporters and quick anion channels, mitochondrial calcium uniporters, voltage-dependent anion channels, vesicular chloride channels, ionotropic purinergic receptors, animal volage-insensitive cation channels, channelrhodopsins, bestrophins, voltage-gated chloride channels H⁺/Cl^- exchangers, plant calcium-permeable mechanosensitive channels, and trimeric intracellular cation channels. Overall, dinoflagellates represent cells able to respond to physical and chemical stimuli utilizing a wide range of G-protein coupled receptors- and Ca²⁺-dependent signaling pathways. The applied approach not only shed light on the ion channel set in dinoflagellates, but also provided the information on possible molecular mechanisms underlying vital cellular processes dependent on the ion transport.

• Journal of Radiation Protection and Research
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• 제48권4호
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• pp.204-212
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• 2023

Background: Isotopes of the projectile may be produced along the beam path during the irradiation of a target by a heavy ion due to inelastic interactions with the media. This study analyzed the production cross-section of carbon (C) and Helium (He) projectile's isotopes resulting from the interactions of these beams with different materials along the beam path. Materials and Methods: In this study, we transport C and He ion beams through different materials. This transportation was made by the Monte Carlo simulation. Particle and Heavy Ion Transport code System (PHITS) has been used for this calculation. Results and Discussion: It has been found that ¹⁰C, ¹¹C, and ¹³C from the ¹²C ion beam and ³He from the ⁴He ion beam are significant projectile's isotopes that have higher flux than other isotopes of these projectiles. The ⁴He ion beam has a higher projectile's isotope production cross-section along the beam path, which adds more impurities to the beam than the ¹²C ion beam. These projectile's isotopes from both the ¹²C and ⁴He ion beams have higher production cross-sections in hydrogenous materials like water or polyethylene. Conclusion: It is important to distinguish these projectile's isotopes from the primary beam particles to obtain a precise and accurate cross-section result by minimizing the error during measurement with a nuclear track detector. This study will show the trend of the production probability of projectile's isotopes for these ion beams.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2008년도 제34회 동계학술대회 초록집
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• pp.205-205
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• 2008

• Corrosion Science and Technology
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• 제4권2호
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• pp.45-50
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• 2005

A 3% NaCl solution of 1 $dm^3$ circulated with 1.5 $dm^3/min$ by a pump for 24 h in the presence of magnetic field. An iron plate immersed in a $100cm^3$ of test solution for 24 h. The rest potential and pH on surface fixed after 3 h. Containing 0~120 ppm of Fe(II) ion, the dissolution in the magnetically treated solution rose comparing with that in the non-magnetically treated solution. The dissolution amount reached to maximum at 50 ppm, then fixed in the non-magnetically treated solution. When Fe(II) ion existed in the magnetically treated solution, dissolution accelerated a little. In the non-magnetic treated solution containing 10~125 ppm of Fe(III) ion existed, the dissolution accelerated. The dissolution amounts reached to maximum at 50 ppm, then decreased from maximum value. In the magnetically treated solution, the dissolution amounts reached to minimum until 50 ppm, then increased from minimum value. The dissolution amounts affected larger with increasing of magnetic flux density. Fe(II), Fe(III) ions and magnetic treatment affected to formation of $Fe(OH)_2$ and/or $Fe_3O_4$ films. The magnetically treated effects memorized about one month.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.59-59
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• 1999

DLC(diamond-like carbon)필름은 다이아몬드와 유사한 강도, 낮은 마차계수, 높은 Optical band gap, NEA(negative electron affinity)등의 우수한 특성을 가지고 있어, 내마모 코팅이나 정보저장 매체의 윤활 코팅, FED(field emission display)의 전계방출소자등 다양한 분야에의 응용이 연구되고 있다. DLC 필름은 PECVD(plasma enhanced chemical vapor deposition), IBAD(ion beam assisted deposition), Laser ablation, Cathodic vacuum arc등의 process를 이용하여 증착되고 있다. 특히 이러한 필름의 물성은 입사되는 이온의 에너지에 의해 좌우되는데, Lifshitz 등의 연구에 의하여 hyperthermal species를 이용한 DLC 필름의 성장은 초기에 subsurface로의 shallow implantation이 일어난 후 높은 sp3 fraction을 갖는 필름이 연속적으로 성장한다는 subplantation model이 제시 되었다. 본 연구에서는 기판과 subplantation 영역이 이후 계속하여 증착되는 순수 DLC 필름의 특성 변호에 미치는 영향에 대하여 관심을 가지고 실험을 행하였다. 본 실험에서는 상기 제시되어 있는 방법보다도 더욱 정확하고도 독립적으로 탄소 음이온의 에너지와 flux를 조절할 수 있는 Cs+ ion beam sputtering system을 이용하여 탄소 음이온의 에너지를 40eV에서 200eV까지 변화시키며 필름을 증착하였다. Si(100) 웨이퍼를 기판으로 사용하였고 증착 압력은 5$\times$10-7torr 였으며 인위적인 기판의 가열은 하지 않았다. 또한 Ion beam deposited DLC film의 growth process를 연구하기 위하여 200eV의 탄소 음이온을 시간(증착두께)을 변수로 하여 증착하였고, 이 때에는 Kaufman type의 gas ion beam을 이용하여 500eV의 Ar+ ion으로 pre-sputering을 행하였다. 탄소 음이온의 에너지와 증착두께에 따라 증착된 film 내의 sp3/sp2 ratio 의 변화를 XPS plasmon loss 와 Raman spectra를 이용하여 분석하였다. 또한 증착두께에 따른 interlayer의 결합상태를 관찰하기 위하여 AES와 XPS 분석을 보조로 행하였다.

• 천문학논총
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• 제10권1호
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• pp.127-134
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• 1995

Recent discovery of an Io-related feature in Jupiter's auroral regions prompted us to search for an or multiplet at $1304{\AA}$ in IUE aurora spectra. In three independent IUE spectra taken on January 18, 1981, we found an emission structure at $1304{\AA}$, with a signal-to-noise of about three. If the structure is due to the OI emission, then it is a direct evidence of oxygen ion precipitation, which may originate from Io and Io torus. The emission rates of the $H_2$ band systems and the or multiplet are about 50 kR and 150 R, respectively. We have constructed high resolution model spectra with the estimated emission rates of $H_2$, OI and SI for the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope. The model spectra clearly show the or and SI mulitplets separated from crowded $H_2$ Lyman and Werner band lines, and therefore it is promising to detect the OI and SI multiplets with the GHRS. Given the possibility that the lo-related feature may be caused by ion precipitations from the Io flux tube, it is likely that the OI emission may be detected in the footprint area of the IO flux tube.