• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3570-3576
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• 2013

Poly(methacrylic acid)-functionalized SBA-15 silicas (denoted as P-x-PMA/SBA-15 where x is molar ratio of TSPM/(TEOS+TSPM) in percentage in the initial mixture) were synthesized by co-condensation of tetraethoxysilane and varying contents of 3-(trimethoxysilyl)propyl methacrylate in acidic medium with the block copolymer Pluronic 123 as a structure directing agent and then polymerization by methacrylic acid in the presence of ammonium persulfate as an initiator. The functionalized materials were characterized by PXRD, TEM, SEM, IR, and $N_2$ adsorption-desorption at 77 K. The investigation of phenol adsorption in aqueous solution on the materials showed that the poly(methacrylic acid)-functionalized mesoporous silicas possess strong adsorption ability for phenol with interaction of various kinds of hydrogen bonds. The adsorption data were fitted to Langmuir isotherms and the maximum adsorption capacity of the three functionalized materials P-5-PMA/SBA-15, P-10-PMA/SBA-15, and P-15-PMA/SBA-15 to be 129.37 mg/g, 187.97 mg/g, and 78.43 mg/g, respectively, were obtained. The effect of the pH on phenol adsorption was studied.

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4109-4116
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• 2012

An efficient solid-phase methodology has been developed for the synthesis of 2-amino and 2-amidobenzo[d]-oxazole derivatives. The key step in this procedure involves the preparation of polymer-bound 2-aminobenzo-[d]oxazole resins 4 by cyclization reaction of 2-hydroxy-phenylthiourea resin 3. The resin-bound 2-hydroxyphenylthiourea 3 is produced by the addition of 2-aminophenol to the isothiocyanate-terminated resin 2 and serve as a key intermediate for the linker resin. This core skeleton 2-aminobenzo[d]oxazole resin 4 undergoes functionalization reaction with various electrophiles, such as alkylhalides and acid chlorides to generate 2-amino and 2-amidobenzo[d]oxazole resins 5 and 6 respectively. Finally, 2-amino and 2-amidobenzo[d]oxazole derivatives 7 and 8 are then generated in good yields and purities by cleavage of the respective resins 5 and 6 under trifluoroacetic acid (TFA) in dichloromethane ($CH_2Cl_2$).

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4035-4040
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• 2012

Presented study describes the synthesis of photo cross-linkable and water soluble hydroxyethyl starch hydroxyethyl methacrylate (HESHEMA) samples with different degree of substitution (DS) by functionalization of hydroxyethyl starch (HES) with hydroxyethyl methacrylate (HEMA) or hydroxyethyl methacrylate carbonylimidazole (HEMACI) in DMSO using two different routes. It was revealed that the reaction time for HESHEMA synthesis can be reduced from 5 days to 24 h by conducting the reaction at $80^{\circ}C$ instead of at room temperature. Solubility of HESHEMA was found to be dependent on DS which in turn was dependent on ratio between HES and HEMA or HEMACI. HESHEMA samples with DS > 0.24 depicted insoluble in water, whereas the samples with DS < 0.05 did not form appreciable gel. HESHEMA samples with appropriate DS were converted into hydrogels by cross-linking polymer chains under UV radiations and resulting HESHEMA hydrogels showed swelling up to 1200%. Application of HESHEMA in controlled drug delivery was investigated by diffusion based encapsulation of Ondansetron, a serotonin 5-$HT_3$ receptor antagonist drug, mainly used for nausea and vomiting treatment.

• 한국재료학회지
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• 제29권8호
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• pp.505-510
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• 2019

Zn-ion supercapacitors (ZICs) show high energy densities with long cycling life for use in electronic devices. Porous Zn electrodes as anodes for ZICs are fabricated by chemical etching process using optimized conditions. The structures, morphologies, chemical bonding states, porous structure, and electrochemical behavior are examined. The optimized porous Zn electrode shows a root mean square of roughness of 173 nm and high surface area of $153{\mu}m^2$. As a result, ZIC using the optimized porous Zn electrode presents excellent electrochemical performance with high specific capacitance of $399F\;g^{-1}$ at current density of $0.5A\;g^{-1}$, high-rate performance ($79F\;g^{-1}$ at a current density of $10.0A\;g^{-1}$), and outstanding cycling stability (99 % after 1,500 cycles). The development of energy storage performance using synergistic effects of high roughness and high surface area is due to increased electroactive sites by surface functionalization of Zn electrode. Thus, our strategy will lead to a rational design and contribute to next-generation supercapacitors in the near future.

• Advances in nano research
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• 제14권6호
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• pp.557-573
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• 2023

The rapid growth of zinc-oxide (ZnO) nanostructures (NSs) on woven carbon fiber (WCF) is reported in this study employing a microwave-aided chemical bath deposition process. The effects of different process parameters such as molar concentration, microwave duration and microwave power on morphologies and growth rate of the ZnO on WCF were studied. Furthermore, an attempt has been taken to study influence of different type of growth solutions on ZnO morphologies and growth rates. The surface functionalization of WCF fabrics is achieved by successful growth of crystalline ZnO on fiber surface in a very short duration through one-step microwave synthesis. The morphological, structural and compositional studies of ZnO-modified WCF are evaluated using field-emission scanning electron microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy respectively. Good amount of zinc and oxygen has been seen in the surface of WCF. The presence of the wurtzite phase of ZnO having crystallite size 30-40 nm calculated using the Debye Scherrer method enhances the surface characteristics of WCF fabrics. The UV-VIS spectroscopy is used to investigate optical properties of ZnO-modified WCF samples by absorbance, transmittance and reflectance spectra. The variation of different parameters such as dielectric constants, optical conductivity, refractive index and extinction coefficient are examined that revealed the enhancement of optical characteristics of carbon fiber for wide applications in optoelectronic devices, carbon fiber composites and photonics.

• Korean Chemical Engineering Research
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• 제51권2호
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• pp.171-180
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• 2013

금속유기구조체(metal-organic frameworks, MOF)는 넓은 비표면적, 규칙적인 구조 및 높게 분산된 금속 성분 등 뛰어난 물리화학적 특성으로 인해 활발한 연구가 이뤄지고 있는 다공성 물질이며, 특히 가스의 흡착, 분리 매체로서 뛰어난 성능이 보고되고 있다. MOF를 이용한 온실가스 이산화탄소의 흡착 연구는 상온 고압 영역에서 이산화탄소 저장 공정과 상온 저압 영역에서 이산화탄소 흡착 공정의 두 범주로 나눌 수 있으며, MOF의 넓은 비표면적 외에도 (1) MOF의 빈 배위결합 자리, (2) MOF의 기능화, (3) MOF의 상호 침투 효과, 및 (4) 이온 교환 효과를 이용한 연구 결과가 보고되고 있다. MOF 물질들은 비교적 낮은 수분 및 열에 대한 안정성이 문제로 제기되고 있으며, 제올라이트 유사 구조체(zeolitic imidazolate frameworks, ZIF) 또는 유기 골격 구조체(covalent organic frameworks, COF) 물질의 이산화탄소 흡착 특성이 거론되고 있다. 본 소고에서는 MOF를 이용한 이산화탄소 흡착에 대한 최근의 연구 결과를 본 연구실의 실험 결과를 중심으로 간략히 소개하고자 한다.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1968-1976
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• 2006

Recombinant E. coli ACV 1003 (recA:: lacZ) was used to measure low concentrations of DNA-damaging chemicals, which produce $\beta$-galactosidase via an SOS regulon system. Very low $\beta$-galactosidase activities of less than 0.01 unit/ml, $\beta$-galactosidase produced through an SOS response corresponding to the 10 ng/ml (ppb) of DNA damaging chemicals in the environment, can be rapidly determined by using an alternative interferometric biosensor with optically flat thin films of porous silicon rather than by the conventional time-consuming Miller's enzyme assay as well as the ELISA method. fu order to enhance the sensitivity in the interferometry, it needs to obtain more uniform distribution and higher biolinking efficiency, whereas interferometric sensing is rapid, cheap, and advantageous in high throughput by using a multiple-well-type chip. In this study, pore size adjusted to 60 nm for the target enzyme $\beta$-galactosidase to be bound on both walls of a Si pore and a calyx crown derivative was apllied as a more efficient biolinker. Furthermore, anti-$\beta$-galactosidase was previously functionalized with the biolinker for the target $\beta$-galactosidase to be specifically bound. When anti-$\beta$-galactosidase was bound to the calyx-crown derivative-linked surface, the effective optical thickness was found to be three times as high as that obtained without using anti-$\beta$-galactosidase. The resolution obtained was very similar to that afforded by the time-consuming ELISA method; however, the reproducibility was still unsatisfactory, below 1 unit $\beta$-galactosidase/ml, owing to the microscopic non-uniform distribution of the pores in the etched silicon surface.

• 공업화학
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• 제30권3호
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• pp.308-312
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• 2019

양친매성 금입자는 그 표면에 소수성 및 친수성 리간드를 결합시켜 합성된다. 이러한 양친매성 입자들은 바이오, 에너지, 광학, 전자 공학 분야 등에 다양하게 활용될 수 있다. 입자 표면의 소수성/친수성 비율은 양친매성 금입자의 물리화학적 특성과 밀접한 관계가 있어 양친매성 금입자를 활용하는데 있어서 상당히 중요한 역할을 한다. 본 연구에서는 양친매성 금입자 합성 과정(리간드 치환반응)에서 온도 변화에 대한 표면의 소수성과 친수성 리간드 비율의 영향을 알아보았다. 치환 반응의 온도가 증가함에 따라서 표면의 친수성 리간드의 비율이 증가하고, 또한 더 적은 친수성 리간드의 비율에서도 양친매성 금입자가 수용액상에 개별적으로 잘 분산되는 것을 확인하였다.

• 전기화학회지
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• 제11권2호
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• pp.105-108
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• 2008

최근, 증폭되는 관심은 창조적인 방법에 따른 CNTs의 합리적인 기능화에 집중하고 있다. 하지만 CNTs의 적지 않은 독성은 아직 논쟁의 이슈가 되어 그 생물학적 응용이 제한되어왔다. CNT의 생체 적합성을 개선하기 위해 본 연구에서는 CNT와 유기적인 티타늄을 시작 물질로 나노 혼성의 CNT-$TiO_2$를 제조하여 전기화학적 거동을 고찰하였다. 본 연구는 개질 된 접촉면이 이질의 전자 전송율을 가속하고, 그 결과, 관련 검출감도를 강화할 수 있었음을 확인하였다. 또한 암의 초기 진단을 위한 생물학적 적합성으로 멀티신호의 민감한 바이오센서의 개발에 새로운 전략으로서 그 잠재력의 응용을 제안하고자 한다.

• Korean Chemical Engineering Research
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• 제53권6호
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• pp.703-708
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• 2015

나노충전제의 우수한 분산성을 얻기 위하여 다중벽 탄소나노튜브(multiwall carbon nanotubes) (MWCNTs)와 poly(propylene gylcol)(PPG)을 ball mill shaker로 혼합한 분산액을 이용하여 폴리우레탄(PU) 나노복합체를 제조하였다. MWCNTs는 과산화수소($H_2O_2$)로 처리하여 표면을 기능화할 수 잇었다. 순수한 MWCNTs를 이용한 PU 나노복합체와 비교한 결과 $H_2O_2$로 처리한 MWCNTs를 이용한 PU 나노복합체의 인장강도와 신율이 높게 나타났다. SEM 이미지에서 보여진 MWCNTs의 우수한 분산성은 표면을 기능화시킴으로서 얻어진 것이다. Carbon black(CB)을 사용한 PU 복합체는 기계적 물성 변화가 거의 없었다. 분산시간의 증가에 따라 PU/MWCNTs 나노복합체들의 인장물성이 상승되었다. 결과적으로 나노충전제의 분산성 향상이 PU/MWCNTs 나노복합체의 인장물성 증가를 가져온 것을 확인하였다.