• Bulletin of the Korean Chemical Society
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• 제35권11호
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• pp.3213-3218
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• 2014

A metal organic framework-supported Nickel nanoparticle (Ni-MOF-5) was successfully synthesized using a simple impregnation method. The obtained solid acid catalyst was characterized by Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption and thermogravimetric analysis (TGA). The catalyst was highly crystalline with good thermodynamic stability (up to $400^{\circ}C$) and high surface area ($699m^2g^{-1}$). The catalyst was studied for the oxidation of ethyl benzene, and the results were monitored via gas chromatography (GC) and found that the Ni-MOF-5 catalyst was highly effective for ethyl benzene oxidation. The conversion of ethyl benzene and the selectivity for acetophenone were 55.3% and 90.2%, respectively.

• 한국수소및신에너지학회논문집
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• 제8권3호
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• pp.101-109
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• 1997

We propose a new concept of hydrogen absorbing alloy, "Laves phase related BCC solid solution". It was firstly found among the phases tormed in multicomponent nominal $AB_2$ alloys which consisted of Zr and Ti for the A metal site and 5A, 6A and 7A transition metals for the B metal sites. In these alloys a BCC solid solution often coexisted with a Laves phase. It showed stability of hydrides and reaction kinetics almost identical to intermetallics such as Laves phase alloys. We prepared an almost pure "Laves phase related BCC solid solution" and found that it had a large hydrogen capacity (more than 2 mass%) and fast hydrogen absorption and desorption kinetics at ambient temperature and pressure. This new hydrogen absorbing alloy may open a new era of hydrogen related application such as hydrogen vehicles.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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• pp.442-445
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• 1999

In this work, to detect of hydrogen in DI water in the generator area of nuclear power plants was fabricated Pd/Pt gate MISFET sensor using Pd membrane. $H_2$ permeation through Pd accounts for external mass transfer, surface adsorption and desorption, transitions to and from the bulk metal, and diffusion within the metal. The identification of pinholes in the generator area of plant is an important safety consideration, as hydrogen build-up gives rise to explosion. For this type of application the sensor needs to be isolated in DI water, accordingly, a Pd membrane was used to separate the DI water. The hydrogen in the DI water was then absorbed on the Pd thin film and diffused into the oil through the thin film. The Pd/Pt gate MISFET sensor, encapsulated by oil, will thereby detect permeated hydrogen.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.475-479
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• 1996

At present studies, we are going to suggest the new type of Perovskite derived catalysts which modify the defects of transition metals impregnated. Perovskite type catalyst is a typical mixed metal oxides, and there are "defect"s (from like that oxygen, cation, crystallic structure) were made by difference from composition, preparing method and so forth. And because this, its electro-magnetic character could be much changed. By using this phenomena, it could utilize the modification of adsorption/desorption characters as well as the catalytic activities in NOx reduction. Because perovskite type catalyst can exchange the metal of the each lattice site freely and it is possible to represent the peculiar.

• Journal of Microbiology and Biotechnology
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• 제12권2호
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• pp.296-300
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• 2002

Bacterial cell surface components are the major factors responsible for pathogenesis and bioremediation. In particular, the surface of a Gram-negative bacterium cell has a variety of components compared to that of a Gram-positive cell. In our previous study, we isolated an isogenic mutant of Bradyrhizobium japonicum, which exhibited altered cell surface characteristics, including an increased hydrophobicity. Polyacrylamide gel electrophoretic analysis of the lipopolysaccharide (LPS) in the mutant demonstrated that the O-polysaccharide part was completely absent. Meanwhile, a gel permeation chromatographic analysis of the exopolysaccharide (EPS) in the mutant demonstrated that it was unaltered. Since LPSs are known to have several anion groups that interact with various cation groups and metal ions, the mutant provided an opportunity to examine the direct role of LPS in metal binding by B. japonicum. Using atomic absorption spectrophotometry, it was clearly demonstrated that LPS was involved in metal binding. The binding capacity of the LPS mutant to various metal ions $(Cd^{2+},\;Cu^{2+},\;Pb^{2+},\;and\;Zn^{2+})$ was 50-70% lower than that of the wild-type strain. Also, through an EPS analysis and desorption experiment, it was found that EPS and centrifugal force had no effect on the metal binding. Accordingly, it would appear that LPS molecules on B. japonicum effect the properties, which precipitate more distinctly metal-rich mineral phase.

• 공업화학
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• 제20권2호
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• pp.117-125
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• 2009

차세대 청정 연료로 각광받고 있는 천연가스를 자동차 등의 이동원의 동력원으로 사용하기 위해 높은 에너지 밀도로 저장하는 것은 매우 중요하다. 특히 상온 및 과히 높지 않은 압력(35~40 기압)에서 흡착을 이용하여 천연가스를 저장(ANG)하는 것은 압축에 의한 CNG 및 냉각에 의한 LNG에 비해 경제적이고 안전하며 사용이 용이한 특성이 있다. 그러나 상업적으로 통용되기 위해 필요한 저장 용량을 얻을 수 있는 경제적인 흡착제가 현재 알려져 있지 않아 다양한 연구가 계속되고 있다. 최근에 많은 연구가 되고 있는 MOF (metal-organic frameworks)를 포함한 나노 세공체도 하나의 답이 될 수 있다. 본 총설에서는 ANG 밀도를 높이기 위해 필요한 흡착제의 물성과 상업적으로 적용하기 위해 요구되는 흡착제 물성에 대해 요약하였다. 높은 에너지 밀도를 위해서는 넓은 표면적, 큰 미세 세공 부피, 적당한 세공 크기 및 높은 밀도 등이 필요하고 낮은 흡탈착 에너지 및 빠른 흡탈착 속도가 요구된다. 또한 탈착시 상압에서 잔존하는 천연가스의 양이 적어 실제 활용할 수 있는 천연가스의 양(delivery)이 높아야 한다. 현재 매우 활발히 연구되고 있는 나노 세공체를 천연가스 저장물질로 적용하고자 하는 연구도 다양하게 이루어지고 있으며 이러한 물성을 만족하는 나노세공체가 개발되기를 기대한다.

• 한국산업보건학회지
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• 제4권1호
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• pp.96-102
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• 1994

Factors affecting non-proficient analytical ability were compared and evaluated by rating of laboratories and round. Analyst Indices between proficient and non-proficient participants were different. Coefficients of determination($R^2$) for standard of toluene, xylene and trichloroethylene of the 4th round between some proficient and non-proficient participants were significantly different(p<0.05). But, there was no difference in the 5th round. Average desorption efficiency of non-proficient participants was 88%-98%, which was lower than 96%-100% of some randomly selected proficient participants. Also non-proficient participants have a large variance of desorption efficiency, 11.79-19.69%. In the 5th round, desorption efficiency of metyl iso-butyl ketone(MIBK) reported by all participants was lower than 90% tested by NIOSH and especially low compared to other analytes. Participants evaluated to be non-proficient in the metal part have 85%-100.84% of average recovery, which was larger variance than 98% of some proficient participants. Although it is difficult to find quantitatively factors causing non-proficiency in analytical ability, pretreatement techniques and experience of analyst seems to be more important factors to produce accurate analytical result.

• 한국환경농학회지
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• 제25권2호
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• pp.157-163
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• 2006

Investigation of Cd and Zn availability in four different soils as affected by the interactions of these two heavy metals was conducted using the metal desorption quantity-intensity (Q/I) isotherms. The soils were artificially contaminated with proper concentrations of Cd and Zn as $CdSO_4\;and\;ZnSO_4$ solutions. DTPA (diethylene triamine pentaacetic acid) - extractable and water-extiactable Cd or Zn from the soils were used as $Q_{Cd}\;or\;Q_{Zn}\;and\;I_{Cd}\;or\;I_{Zn}$ factors, respectively. The coefficient of determination for Cd and Zn desorption Q/I linear regression in the soils ranged from 0.947 to 0.999, which indicated that Q and I factors were closely correlated. The buffering capacity of Cd, $BC_{Cd}$, in the soils decreased with increasing Zn treatments, and the $BC_{Cd}$ values were ranged between 205.8 and 2255.6. The decreases of $BC_{Cd}$ values were mainly dependent upon the increases of $I_{Cd}$ factors. However, Zn buffering capacity. $BC_{Zn}$ decreased with increasing Cd treatments in acidic soils, and increased in neutral and calcareous alkaline soils. The $BC_{Cd}$ values were ranged from 143.2 to 6158.0. The values of $BC_{Zn}$ as influenced by the treatments of Cd were also controlled by the solubility of water-extractable Zn, $I_{Zn}$ factor. The solubility of water-extractable Cd and Zn was significantly dependent upon the changes of soil pH that were impacted by the treatment of Zn and Cd, respectively. Also, the availability of Cd was higher than Zn availability in the acidic and neutral soils, but Zn was higher than Cd in the calcareous alkaline soil.

• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1470-1474
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• 2009

Thermal and photochemistry of methyl iodide ($CH_3I)\;adsorbed\;on\;D_2O$ ice film on Cu(111) at 100 K were studied using temperature-programmed desorption (TPD) time-of-flight mass spectrometry (TOF-MS), X-ray and ultraviolet photoelectron spectroscopies. On the basis of TPD, multilayer and monolayer $CH_3I$ molecules desorb from $D_2O$ ice layer at 120 and 130 K, respectively. Photo-irradiation at 100 K exhibits dramatic changes in the TPD and I $3d_{5/2}\;XPS\;of\;CH_3I$ on ice film, due to a dramatic dissociation of $CH_3I$. The dissociation is likely activated by solvated electrons transferred from the metal substrate during photo-irradiation. No other photo-initiated reaction products were found within our instrumental detection limit. During photo-irradiation, the $CH_3I$, $CH_3$ and I could be trapped (or solvated) in ice film by rearrangement (and self-diffusion) of water molecules. A newly appeared parent molecular desorption peak at 145 K is attributed to trapped $CH_3I$. In addition, the $CH_3$ and I may diffuse through ice and chemisorb on Cu(111), indicated by TPD and I $d_{5/2}$ XPS taken with photo-irradiation time, respectively. No molecular ejection was found during photo-irradiation at 100 K. The work functions for $CH_3I/Cu(111),\;D_2O/Cu(111)\;and\;CH_3I/D_2$O/Cu(111) were all measured to be about 3.9 eV, 1.0 eV downward shift from that of clean Cu(111).

• 한국수산과학회지
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• 제32권4호
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• pp.399-403
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• 1999

우리나라 인근 해역에서 가장 쉽게 채취할 수 있는 해조류 중의 하나인 S. sagamianum을 이용한 Pb 및 Cr의 생체흡착 실험을 수행하였다. Pb 및 Cr은 15분 안에 흡착 평형에 도달하였으며, 평형흡착량은 각각 224.5mg Pb/g biomass 및 77.5mg Cr/g bio-mass로서 Pb의 흡착량이 Cr보다 약 3배정도 높았다. 또한 pH가 감소할수록 Pb 및 Cr의 홉착량은 감소하였으나 Pb가 상대적으로 많은 영향을 받는 것으로 나타났다. Pb, Cr, Cu 및 Cd 혼합용액에서는 Pb>Cu>Cr>Cd 순으로 흡착하였으며, Pb 및 Cr 이온이동량 존재하는 용액에서의 흡착은 거의 1 : 1로 흡착이 이루어졌다. Pb 및 Cr흡착 후에 0.1 M HCl, 0.1 M $HNO_3$ 및 0.1 M EDTA으로 탈착 실험을 수행하니, Pb는 의 경우에는 $95\%$이상 탈착되었으나 Cr의 경우 S. sagamianum와의 결합력이 상대적으로 강하여 탈착율이 $51\%$이하로 낮았다.