• 한국전기전자재료학회논문지
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• 제14권10호
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• pp.835-844
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• 2001

In this paper, we report the successful growth of crystalline carbon nitride films in Si(100) by a laser-electric discharge method. The laser ablation of the target leads to vapor plume plasma expending into the ambient nitrogen arc discharge area. X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy(AES) were used to identify the binding structure and the content of the nitrogen species in the deposited films. The surface morphology of the films with a deposition time of 2 hours is studied using a scanning electron microscopy (SEM). In order to determine the structural crystalline parameters, X-ray diffraction (XRD) was used to analysis the grown films.

• 공업화학
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• 제35권1호
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• pp.23-28
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• 2024

세슘은 높은 수용성으로 인하여 인체에 쉽게 침투하여 암 또는 DNA의 변형을 유발하는 잠재적인 독성 오염물질이다. 본 연구에서는 활성탄소의 세슘 흡착 능력을 향상시키고자 오존 처리를 통하여 활성탄소 표면에 산소 작용기를 도입하였다. 오존 처리 시간의 증가에 따라 활성탄소 표면의 산소함량이 증가하였다. 이후 활성탄소와 세슘 사이의 정전기적 상호작용이 더욱 원활하게 이루어져 모든 시료의 세슘 이온 흡착 효율이 향상되었다. 특히 반응기 내부 오존 농도를 50000 ppm으로 하여 7 min 동안 오존 처리한 시료는 약 12%의 높은 산소 작용기 함량을 보이며 97.6%의 가장 높은 세슘 제거 효율을 보였다. 한편, 5 min 동안 처리된 시료는 7 min간 반응한 시료와 비교하여 0.3%의 근소한 세슘 제거율 차이를 보였으며, 이는 오존 기체의 반응 특성으로 인한 두 시료의 표면화학적 유사성에 기인한다. 그러나, 오존 처리된 활성탄소의 세슘 흡착 성능은 활성탄소의 비표면적 및 기공 구조도 중요하지만 표면에 도입된 산소 작용기 양이 주된 영향을 미치는 것으로 판단된다.

• Carbon letters
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• 제26권
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• pp.66-73
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• 2018

We assessed the effects of combining bio-char with straw residue mulching on the loss of soil soluble nutrients and citrus yield in sloping land. The two-year study showed that straw residue mulching (ST) and bio-char application combined with straw residue (ST+BC) can significantly reduce soil soluble nutrient loss when compared with the control treatment (CK). The comparative volume of the soil surface runoff after each of the treatments was as follows: CK > ST > ST + BC. Compared with the CK, the runoff volume of the ST was reduced by 13.6 % and 8.5 % in 2014 and 2015, respectively. Compared with the CK, combining bio-char with the ST application reduced the loss of soluble nitrogen and improved the soil total nitrogen content reaching a significant level in 2015. It dramatically increased the soil organic matter content over the two year period (36.3% in 2014, 50.6% in 2015) as well as the carbon/nitrogen ratio (C/N) (16.6% in 2014 and 39.3% in 2015). Straw mulching combined with bio-char showed a trend for increasing the citrus yield.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2652-2659
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• 2020

The methyl iodide (CH₃I) removal performance of tri-ethylene-di-amine impregnated activated carbon (TEDA-AC) used in the air cleaning unit of nuclear power plants (NPPs) should be maintained at least 99% between 24 month-performance test period. In order for evaluating the effectiveness of TEDA-AC on the removal performance of CH₃I in nuclear power plant during the operation of NPPs, the long-term test for up to 15 months was carried out under the simulated operating conditions (e.g., 25 ℃, RH 50%, ppb level poisoning gases injection) at nuclear power plants (NPPs). The TEDA-AC samples were analyzed with the Brunauer-Emmett-Teller (BET) specific surface area and TEDA content as well as CH₃I penetration test. It is clearly evident that more than 99% of CH₃I removal performance of TEDA-AC was observed in the TEDA-AC samples during 15 months of long-term operation under the simulated NPP operating conditions including the ppb level of organic and oxide form of poisoning gases. BET specific surface area and TEDA content that can affect the CH₃I removal performance of TEDA-AC were also maintained as those in new TEDA-AC during 15 months of long-term operation.

• 폴리머
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• 제37권4호
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• pp.470-477
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• 2013

가공이 쉬우면서도 성능이 우수한 염료 감응 태양 전지(DSSC)용 상대 전극을 제조하기 위하여 다중벽 탄소 나노튜브(MWCNT) 기반의 고충전 나노복합 페이스트를 제조하고, MWCNT의 분산 제어가 미치는 영향에 대하여 조사하여 보았다. MWCNT의 분산성을 향상시키기 위하여 폴리스티렌 기반의 기능성 블록 공중합체를 리빙 라디칼 중합법으로 합성하여 MWCNT의 표면 개질제로 사용하였으며, 적절한 용매 조건의 선택을 통하여 고충전 나노복합 페이스트의 가공성이 향상되는 것을 확인할 수 있었다. MWCNT의 분산 제어를 통해 이를 상대 전극으로 도입한 DSSC의 광전 변환 효율이 향상됨을 확인할 수 있었으며, 이는 볼밀법을 이용한 MWCNT의 물리적 분산을 통해서도 검증할 수 있었다. 미량의 platinum(Pt) 나노입자와 복합화시킬 경우, 표준 Pt 상대 전극보다도 더 우수한 성능을 가지는 MWCNT 기반 상대 전극을 제조할 수 있음을 확인하였다.

• Corrosion Science and Technology
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• 제8권3호
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• pp.103-109
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• 2009

An epoxy coating was designed to give a hydrophobic property on its surface by modifying it with three types of Amino Terminated Polydimethylsiloxane (ATP), and then effects of the modification on the structure, surface hydrophobic tendency, water transport behavior and hence corrosion protectiveness of the modified epoxy coating were examined using FT-IR spectroscopy, hydrothermal cyclic test, and impedance test. The surface of epoxy coating was changed from hydrophilic to hydrophobic property due primarily to a phase separation tendency between epoxy and modifier by the modification. The phase separation tendency is more appreciable when modified by ATP with higher molecular weight ATP at higher content. Water transport behavior of the modified epoxy coating decreased more in that with higher hydrophobic surface property. The resistance to localized corrosion of the modified epoxy coated carbon steel was well agreed with its water transport behavior and hydrophobic tendency.

• 한국응용과학기술학회지
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• 제30권2호
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• pp.362-370
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• 2013

Coconut shell 계 상용 활성탄을 후처리하여 EDLC 전극재로 적용하였다. Coconut shell계 활성탄을 별도의 처리없이 EDLC 전극재로 사용하였을 때, 초기 무게용량 및 부피용량은 66 F/g 및 39 F/cc이었고, 100 사이클 충 방전을 반복한 후, 각각 54 F/g 및 32 F/cc로 감소하여 82%의 충 방전효율을 나타내었다. 충 방전 반복에 따른 용량의 감소폭이 크며, CV 특성에서 부반응에 의한 분극현상이 발생하여 전극재로 적합하지 않았다. 상업용 활성탄에 포함된 불순물을 효율적으로 제거하기 위하여 알칼리 및 산 처리를 하였고, 그 후 세공 분포와 표면의 산성 관능기 함량을 제어하기 위하여 질소 분위기에서 열처리하였다. 알칼리 및 질산처리 한 후 $800^{\circ}C$에서 열처리한 전극재의 경우, 초기부피용량 44 F/cc, 100사이클 후 42 F/cc로서 실용화 가능한 수준의 높은 부피용량 및 95% 이상의 높은 충 방전 효율을 나타내었다.

• 공업화학
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• 제23권3호
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• pp.313-319
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• 2012

본 연구에서는 Polyacrylonitrile (PAN)계 탄소섬유 표면에 구리도금 표면처리가 탄소섬유 강화 복합재료의 기계적 계면 특성에 미치는 영향에 관하여 관찰하였다. 탄소섬유 표면특성은 주사전자현미경, X-선 광전자 분광법, X-선 회절분석기, 접촉각 측정기로 측정하였고, 탄소섬유 강화 복합재료의 기계적 계면 물성은 층간전단강도(interlaminar shear strength, ILSS)와 파괴인성(critical stress intensity factor, $K_{IC}$)측정을 통하여 알아보았다. 실험결과로부터, 기계적 계면물성은 탄소섬유 표면에 COOH group과 도금된 구리함량이 증가됨에 따라 순차적으로 증가되는 것이 확인되었으나, 도금시간을 길게 하여 과량의 구리가 도입되었을 경우 기계적 계면 물성을 도리어 감소시키는 것으로 확인되었다. 결론적으로 구리함량이 탄소섬유 복합재료의 기계적 계면물성을 결정하는 중요 요소라 판단되나, 최적의 함량이상에서는 계면분리에 의한 물성저하의 원인이 될 수 있다.

• 한국광물학회:학술대회논문집
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• 한국광물학회.한국암석학회 2001년도 공동학술발표회 논문집
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• pp.52-52
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• 2001

Clays coated with cationic surfactants (organoclays) have been investigated due to their effectiveness in sorbing organic compounds from water The objectives of this study were to (1) study the sorption characteristics or a cationic surfactant (HDTMA) to clay minerals; (2) examine the partitioning of HOC (naphthalene) to the adsorbed surfactants within the context of the first objective, and (3) develop overall HOC distribution coefficients that consider sorbed surfactant amounts. The sorption of hydrophobic organic contaminant was due to partitioning of the organics into the organic pseudophase created by the surfactant tail groups. Sorption of naphthalene by HDTMA-clays at different surfactant surface coverages revealed that the naphthalene K$\_$d/ values were affected by the surface concentration of surfactant. In our study the kaolinite was modified with a cationic surfactant to achieve different fractional organic carbon contents and different surfactant molecule configurations on the surface. All of the sorption isotherms were nearly linear and could be described by a distribution coefficient (K$\_$d/). The sorption of naphthalene by the surfactant-modified kaolinite was found to be dependent on the bound surfactant molecule configuration as well as on the fractional organic carbon content but halloysite was not affected by the increase of surfactant amounts. Results from this investigation provide additional insight into the role that sorbed surfactant structure plays in HOC partitioning.

• 열처리공학회지
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• 제23권2호
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• pp.83-89
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• 2010

Diamond-like carbon (DLC) coating was studied to be a good tribological problem-solver due to its low friction characteristics and high hardness. However, generally hydrogenated DLC film has shown a weak thermal stability above $300^{\circ}C$. However, the silicon doping DLC process by DC pulse plasma enhanced chemical vapor deposition (PECVD) for the new DLC coating which has a good characterization with thermal stability at high temperature itself has been observed. And we were discussed a process for optimizing silicon content to promote a good thermal stability using various tetramethylsilane (TMS) and methane gas at high-temperature. The chemical compositions of silicon-containing DLC film was analyzed using X-ray photoelectron spectroscopy (XPS) before and after heat treatment. Raman spectrum analysis showed the changed structure on the surface after the high-temperature exposure testing. In particular, the hardness of silicon-containing DLC film showed different values before and after the annealing treatment.