• Bulletin of the Korean Chemical Society
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• 제23권10호
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• pp.1394-1398
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• 2002

A novel copper(II) membrane electrode based on diphenylisocyanate bis(acetylacetone) ethylenediimine (DIBAE), as a new hexadentates Schiff's base was prepared. The electrode exhibited a Nernstian response for Cu$^{2+}$ ions over a wide concentration range (1.0 ${\times}$ 10$^{-1}$ to 1.0 ${\times}$ l0$^{-6}$ M) with a limit of detection of 6.0 ${\times}$ 10$^{-7}$ M (39 ppb). The sensor shows a fast response time (15s) and the membrane can be used for more than 4 months without observing any major deviation. The electrode revealed very good selectivity with respect to many cations including alkali, alkaline earth, transition and heavy metal ions. The proposed sensor could be used in a pH range of 3.0-7.5. It was applied to the direct potentiometric determination of copper in black tea, and in wastewater of copper electroplating samples. The electrode was also used in potentiometric titration of the copper(II) ion with EDTA.

• Bulletin of the Korean Chemical Society
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• 제28권1호
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• pp.68-72
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• 2007

A new PVC membrane potentiometric sensor that is highly selective to Hg2+ ions was prepared, using bis(2-hydroxybenzophenone) butane-2,3-dihydrazone (HBBD) as an excellent hexadendates neutral carrier. The sensor works satisfactorily in the concentration range of 1.0 × 10-6 to 1.0 × 10-1 mol L-1 (detection limit 4 × 10-7 mol L-1) with a Nernstian slope of 29.7 mV per decade. This electrode showed a fast response time (~8 s) and was used for at least 12 weeks without any divergence. The sensor exhibits good Hg2+ selectivity for a broad range of common alkali, alkaline earth, transition and heavy metal ions (lithium, sodium, potassium, magnesium, calcium, copper, nickel, cobalt, zinc, cadmium, lead and lanthanum). The electrode response is pH independent in the range of 1.5-4.0. Furthermore, the developed sensor was successfully used as an indicator electrode in the potentiometric titration of mercury ions with potassium iodide and the direct determination of mercury in some binary and ternary mixtures.

• 분석과학
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• 제13권4호
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• pp.428-432
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• 2000

새로운 캘릭스[4]크라운 화합물을 이온 선택성 물질로 사용하고 지지체로 PVC(polyvinyl chloride), 가소제로 DOS(dioctyl sebacate)를 사용하여 이온선택성 막전극을 제작 하였다. 제작한 막전극을 지시전극으로 사용하여 알칼리, 알칼리토금속 이온에 대하여 각각의 감응전위를 측정한 결과, pH7.20 Tris buffer에서 $10^{-5}-10^{-1}M$ 농도의 변화에 따른 $Cs^+$이온의 감응전위가 이론적인 Nernst식 기울기에 가까운 52.3 mV/decade로 직선성이 잘 성립하는 감응전위를 나타내었다. $Cs^+$이온 농도변화에 따른 막의 감응시간은 $t_{90%}$=10sec이었고, 막의 사용기간은 2개월 정도이다.

• Mass Spectrometry Letters
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• 제12권4호
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• pp.126-130
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• 2021

The mass spectrometry (MS) provides the mass-to-charge ratios of atoms, molecules, stable/metastable complexes, and their fragments. I have taken a long journey with MS to address outstanding issues and problems by experiments and theory and gain insights into underlying principles in chemistry. By looking through the mass-to-charge ratio, I have studied thermochemical problems in silicon chemistry, the infrared multiphoton dissociation spectroscopy of organometallic intermediates, unimolecular dissociations of halotoluene radical cations, and the kinetics of association/dissociation of alkali halide triple ions with Lewis bases. Various MS platforms have been used to characterize non-covalent interactions between porphyrins and fullerenes and those between the group IIB ions and trioctylchalcogenides, and to examine the binding of the group IA, IIA and porphyrin ions to G-quadruplex DNA. Recently, I have focused on mass-balanced H/D isotope dipeptide tags for MS-based quantitative proteomics, a simple chemical modification method for MS-based lipase assay, and the kinetics and dynamics of energy-variable collision-induced dissociation of chemically modified peptides. Now, I see an important role of MS in global issues in the post-COVID era, as the society demands high standards for indoor air quality to contain the airborne-pathogen transmission as well as in-situ monitoring and tracking of carbon emissions to reduce global warming.

• 보존과학회지
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• 제35권1호
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• pp.51-60
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• 2019

This paper provides quantitative data that describes the evolution of the air quality in the Whale and Sea Museum, located in the Iwate prefecture, collected after the 2011 Great East Japan Earthquake and tsunami. The museum was damaged significantly by the disaster, and restoration works continued for over six years. The air quality in the temporary storage facility and museum was monitored during the rehabilitation process. Evaluation of air quality is carried out by gas chromatography- mass spectrometry, ion chromatography and high-performance liquid chromatography. The results showed that the characteristics of the chemical components differed depending on the measurement locations inside the building. The museum atmosphere tended to be alkaline as the airtightness increased because of the maintenance works at the entrance. It was also determined that it was necessary to study the intake/exhaust routes and to clean them according to the contamination degree. In Japan, there are recommended museum air quality standards for acetic acid, formic acid, alkali, and aldehydes. The results indicated that these standards should not be used as a reference for damaged museums. Furthermore, at the temporary storage facilities for to store the collections during the rehabilitation of the museum, solvents such as ethyl benzene, toluene, and xylene are initially abundant, although they can be reduced by ventilation, while other components such as 2E1H was confirmed in this case are likely to remain.

• Bulletin of the Korean Chemical Society
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• 제16권3호
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• pp.265-269
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• 1995

Complexation of ortho-xylyl-17-crown-5 (X17C5) with alkali metal ions in acetonitrile was studied by 7Li and 23Na NMR spectroscopy. The complex formation constants of X17C5 with LiI, LiSCN, NaI, and NaSCN were determined by investigating the changes in the chemical shifts as a function of the concentration ratio of X17C5 to metal ion. It was found that X17C5 forms 1:1 complex with Li+ and Na+ ions and the log Kf's for the complexation with LiI, LiSCN, NaI, and NaSCN were determined to be 2.88, 2.43, 2.53, and 2.30, respectively. In particular, the kinetics of complexation of X17C5 with Na+ was investigated by the method of 23Na NMR lineshape analysis. Activation energies were determined from Arrhenius plot of the resultant rate constant data to be 25.4 kJ/mol for NaI and 15.1 kJ/mol for NaSCN. Other kinetic parameters were also calculated by employing the Eyring equation. The decomplexation rates measured were 1.82 × 104 M-1s-1 for NaI and 1.50 × 104 M-1s-1 for NaSCN. It is concluded that the decomplexation mechanism is predominantly a bimolecular cation exchange for both cases.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.144-145
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• 2020

Recently, the cement industry has been using various wastes as raw materials and fuel for cement as an eco-friendly business. However, most of these waste resources contain large amounts of chloride and alkali, which are concentrated in manufacturing facilities and adversely affect cement production products. Accordingly, in the cement production process, the chlorine ion contained in cement is managed by introducing the Chlorine Bypass System (CBS) into the manufacturing facility and releasing the dust. However, the processing volume of CBS-Dust has been limited due to the shortage of domestic processing companies, and the cost has also been raised, requiring measures to be taken in dealing with CBS-Dust. In this study, rheological properties of CBS-Dust incorporated paste are tested. With the increase of CBS-Dust, flow was decreased due to enhanced viscosity.

• 대한약리학회지
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• 제26권1호
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• pp.35-49
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• 1990

A highly purified $(Na^+,\;K^+)-ATPase$ from the rectal gland of Squalus acanthias and from the electric organ of Electrophorus electricus has been used to raise antibodies in rabbits. The 97,000 dalton catalytic subunit and glycoprotein derived from the rectal gland of spiny shark were also used as antigens. The two $(Na^+,\;K^+)-ATPase$ holoenzymes and the two shark subunits were antigenic. In Ouchterlony double diffusion experiments, these antibodies formed precipitation bands with their antigens. Antibodies prepared against the two subunits of shark holoenzyme also formed precipitation bands with their antigens and shark holoenzyme, but not with eel holoenzyme. These observations are in good agreement with inhibitory effect of these antibodies on the catalytic activity of $(Na^+,\;K^+)-ATPase$ both from the shark and the eel, since there is very little cross-reaction between the shark anticatalytic subunit antibodies and the eel holoenzyme. The maximum antibodies titer of the anticatalytic subunit antibodies is found to be 6 weeks after the initial single exposure to this antigen. Multiple injections of the antigen increased the antibody titer. However, the time required to produce the maximum antibody titer was approximately the same. These antibodies also inhibit catalytic activity of $(Na^+,\;K^+)-ATPase$ vesicles reconstituted by a slow dialysis of cholate after solubilization of the enzyme in a presonicated mixture of cholate and phospholipid. In these reconstituted $(Na^+,\;K^+)-ATPase$ vesicles, effects of these antibodies on the fluxes of $Na^+$, $Rb^+$, and $K^+$ were investigated. Control or preimmune serum had no effect on the influx of $^{22}Na^+$ or the efflux of $^{86}Rb^+$. Immunized sera against the shark $(Na^+,\;K^+)-ATPase$ holoenzyme, its glycoprotein or catalytic subunit did inhibit the influx of $^{22}Na^+$ and the efflux of $^{86}Rb^+$. It was also demonstrated that these antibodies inhibit the coupled counter-transport of $Na^+$ and $K^+$ as studied by means of dual labeling experiments. However, this inhibitory effect of the antibodies on transport of ions in the $(Na^+,\;K^+)-ATPase$ vesicles is manifested only on the portion of energy and temperature dependent alkali metal fluxes, not on the portion of ATP and ouabain insensitive ion movement. Simultaneous determination of effects of the antibodies on ion fluxes and vesicular catalytic activity indicates that an inhibition of active ion transport in reconstituted $(Na^+,\;K^+)-ATPase$ vesicles appears to be due to the inhibitory action of the antibodies on the enzymatic activity of $(Na^+,\;K^+)-ATPase$ molecules incorporated in the vesicles. These findings that the inhibitory effects of the antibodies specific to $(Na^+,\;K^+)-ATPase$ or to its subunits on ATP and temperature sensitive monovalent cation transport in parallel with the inhibitory effect of vesicular catalytic activity by these antibodies provide direct evidence that $(Na^+,\;K^+)-ATPase$ is the molecular machinery of active cation transport in this reconstituted $(Na^+,\;K^+)-ATPase$ vesicular system.

• 한국진공학회지
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• 제19권2호
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• pp.114-120
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• 2010

일반적으로 결정질 실리콘 태양전지에서 표면에 텍스쳐링(texturing)하는 것은 알칼리 또는 산성 같은 화학용액을 사용하고 있다. 그러나 실리콘 부족으로 실리콘의 양의 감소로 인하여 웨이퍼 두께가 감소하고 있는 추세에 일반적으로 사용하고 있는 습식 텍스쳐링 방법에서 화학용액에 의한 많은 양의 실리콘이 소모되고 있어 웨이퍼의 파손이 심각한 문제에 직면하고 있다. 그리하여 습식 텍스쳐링 방법보다는 플라즈마로 텍스쳐링할 수 있는 건식 텍스쳐링 방법인 RIE (reactive ion etching) 기법이 대두되고 있다. 그리고 습식 텍스쳐링으로는 결정질 실리콘 태양전지의 반사율을 10% 이하로는 낮출 수가 없다. 다결정 실리콘 웨이퍼 표면에 텍스쳐링을 하기 위하여 125 mm 웨이퍼 144개를 수용할 수 있는 대규모 플라즈마 RIE 장비를 개발하였다. 반사율을 4% 이하로 낮추기 위하여 공정가스는 $Cl_2$, $SF_6$, $O_2$를 기반으로 RIE 텍스쳐링을 하였고 텍스쳐링의 모양은 공정가스, 공정시간, RF 주파수 등에 의해 조절이 가능하였다. 본 연구에서 RIE 공정을 통하여 16.1%의 변환효율을 얻었으며, RF 주파수가 텍스쳐링의 모양에 미치는 영향을 살펴보았다.

• 한국가스학회지
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• 제9권4호
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• pp.17-25
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• 2005

탈알루미늄 및 알칼리/알칼리토금속 양이온을 교환한 Y형 제올라이트 촉매를 제조하였다. 제조한 촉매물질의 원소조성 및 구조 변화를 ICP-AES, XRF 및 XRD와 같은 각종 분광학적 방법으로 분석하였으며, NO-TPD 실험을 통한 표면흡착종의 탈착 거동을 조사하였다. 탈알루미늄 처리 후 출발물질인 NaY보다 촉매물질의 Si/Al비는 증가하였으며, 탈알루미늄 후 Cs및 Ba양이온으로 교환한 Y형 제올라이트의 경우 Si/Al비가 부가적으로 조금 더 감소하였다. 탈알루미늄 처리한 촉매는 Al원자의 탈리로 기본골격의 파괴가 심화되어 framework (tetrahedral)구조가 감소하고 non-framework (octahedral) 구조가 증가하였다. 이러한 현상은 스팀처리시간이 많아질수록 증가하였으며 양이온을 교환한 후에는 더 크게 나타났다. NO-TPD 실험에서 탈알루미늄 및 양이온 교환 후 촉매의 활성점을 나타내는 탈착 봉우리들은 저온으로 이동하였으며, 스팀처리시간이 많아질수록 탈착 봉우리가 상대적으로 저온에서 나타났다. 탈알루미늄 및 양이온 교환을 한 Y형 제올라이트는 교환된 양이온과 탈알루미늄으로 인한 non-framework (octahedral) 구조의 생성이 촉매의 활성에 미치는 영향이 더 큰 것으로 나타났다.