• 방사선산업학회지
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• 제4권4호
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• pp.347-352
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• 2010

In this study, we addressed a novel nanosized curdlan-silica complex, which is curdlan bound to silica, for the development of a sustain-releasing micro element fertilizer formulation. The complex was obtained as follow steps; First, Curdlan polymer, sodium silicate ($Na_2SiO_3$) and isopropyl alcohol were dissolved in DDW. Next the resultant solution was irradiated by $^{60}Co$ gamma-irradiator (150 TBq of capacity; ACEL, Canada). Then $MgSO_4$ was treated with the resultant solution. The obtained colloidal solution was dried by freeze dryer. Finally, we obtained a novel nanosized curdlan-silica formulation containing $MgSO_4$ from the colloidal solution. The morphology of the complex was characterized by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The nanosized curdlan-silica complex has a particle size ranging from 20 to 80 nm and high stability. Our results suggested that the nano-complex can be applicable to use in various sustain-releasing formulation for pesticide delivery system (PDS).

• 한국표면공학회지
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• 제38권1호
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• pp.37-43
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• 2005

Nanosized titanium-colloid particles were prepared by sol-gel method. The physical properties, such as thermal stability, crystallite size and crystallinity according to synthesis condition have been investigated by TEM, XRD, SEM, TGA and DTA. In addition, Zinc phosphating has been studied in order to compare the phosphating characterization of prepared nanosized titanium-colloid particles. The major phase of all the prepared titanium-colloid particles was an amorphous structure regardless of synthesis temperature and the structure was composed of phoshate complex and titanium. The micrographs of HR- TEM showed that nanosized titanium-colloid particles possessed a spherical morphology with a narrow size distribution. The crystallite size of the titanium-colloid particles synthesized at 80℃ was 4-5 nm and increased to 8-10 nm with an increase of synthesis temperature (150℃). In addition, the coating weight increased with an increase of temperature of phosphating solution and when the concentration of titanium-colloid was 2.0 g/l, the coating weight was 1.0 g/㎡.

• 방사선산업학회지
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• 제7권2_3호
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• pp.171-176
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• 2013

In previous study, the novel nanosized curdlan-silica complex for a sustain-releasing effect was developed by using gamma-irradiation. It can be applicable to use in various sustainr-eleasing formulation in agriculture industry. This study was conducted to investigate its storage stability and environmental toxicity in an accelerated condition. The complex samples were treated with high temperature condition ($65^{\circ}C$) during 3 weeks, and then sustain-releasing property of complex was verified thereby using Ion Chromatography on a weekly basis. The morphology of the complex was characterized using scanning electron microscopy (SEM). Results of Ion Chromatography analysis showed that sample treated for 3 weeks was similar to sustain-releasing pattern of non-treatment sample. We verify concluded that the complex is able to keep its sustain-releasing property and sustained-releasing in 3 years. Also the formulation has no environmental toxicity.

• Macromolecular Research
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• 제12권6호
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• pp.573-580
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• 2004

To prepare chitosan-based polymeric amphiphiles that can form nanosized core-shell structures (nanopar­ticles) in aqueous milieu, chitosan oligosaccharides (COSs) were modified chemically with hydrophobic cholesterol groups. The physicochemical properties of the hydrophobized COSs (COSCs) were investigated by using dynamic light scattering and fluorescence spectroscopy. The feasibility of applying the COSCs to biomedical applications was investigated by introducing them into a gene delivery system. The COSCs formed nanosized self-aggregates in aqueous environments. Furthermore, the physicochemical properties of the COSC nanoparticles were closely related to the molecular weights of the COSs and the number of hydrophobic groups per COS chain. The critical aggregation concentration values decreased upon increasing the hydrophobicity of the COSCs. The COSCs effi­ciently condensed plasmid DNA into nanosized ion-complexes, in contrast to the effect of the unmodified COSs. An investigation of gene condensation, performed using a gel retardation assay, revealed that $COS6(M_n=6,040 Da)$ containing $5\%$ of cholesteryl chloroformate (COS6C5) formed a stable DNA complex at a COS6C5/DNA weight ratio of 2. In contrast, COS6, the unmodified COS, failed to form a stable COS/DNA complex even at an elevated weight ratio of 8. Furthermore, the COS6C5/DNA complex enhanced the in vitro transfection efficiency on Human embryonic kidney 293 cells by over 100 and 3 times those of COS6 and poly(L-lysine), respectively. Therefore, hydrophobized chitosan oligosaccharide can be considered as an efficient gene carrier for gene delivery systems.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.189-189
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• 2006

The self-assembly of supramolecular dendrimers allows the rapid construction of nanosized structures with regularly ordered features that depend on the shape of the molecules and the relative strength of the intra-and intermolecular interactions. Here we report on a dramatic improvement in the degree of control and selectivity in the orientation of fan-shaped supramolecular molecules over a large area, which has been achieved by confined geometries and applied fields. The order and orientation of supramolecular dendrimers can be controlled by surface anchoring in confined geometries. POM, SEM, TEM, AFM and XRD results show that the molecules form the complicated defect-ordering in the microchannels with different feature sizes. We show that these defect domains are strongly influenced by the boundary and feature size of the surfaces. This technique can be used to create a grain size in the plane of the film that is much larger than that which can be achieved using previously reported soft-material based pattering.

• 한국산업융합학회 논문집
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• 제4권2호
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• pp.149-155
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• 2001

The use of primitive cell volume and zero order Laue (ZOLZ) pattern is proposed to identify phase in a complex microstructure. Single convergent beam electron pattern containing higher order Laue zone ring from a nanosized region is sufficient to calculate the primitive cell volume of the phase, while ZOLZ pattern is used to determine the zone axis of the crystal. A computer program is used to screen out possible phases from the value of measured cell volume from convergent beam electron diffraction (CBED) pattern. Indexing of ZOLZ pattern follows in the program to find the zone axis of the identification from a single CBED pattern. An example of the analysis is given from the rapidly solidified $Al-Al_3Ti$ system.

• 한국분말재료학회지
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• 제26권3호
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• pp.220-224
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• 2019

The aluminum (Al)/copper oxide (CuO) complex is known as the most promising material for thermite reactions, releasing a high heat and pressure through ignition or thermal heating. To improve the reaction rate and wettability for handling safety, nanosized primary particles are applied on Al/CuO composite for energetic materials in explosives or propellants. Herein, graphene oxide (GO) is adopted for the Al/CuO composites as the functional supporting materials, preventing a phase-separation between solvent and composites, leading to a significantly enhanced reactivity. The characterizations of Al/CuO decorated on GO(Al/CuO/GO) are performed through scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy mapping analysis. Moreover, the functional bridging between Al/CuO and GO is suggested by identifying the chemical bonding with GO in X-ray photoelectron spectroscopy analysis. The reactivity of Al/CuO/GO composites is evaluated by comparing the maximum pressure and rate of the pressure increase of Al/CuO and Al/CuO/GO. The composites with a specific concentration of GO (10 wt%) demonstrate a well-dispersed mixture in hexane solution without phase separation.

• 폴리머
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• 제34권3호
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• pp.185-190
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• 2010

전기방사공정에 의해 고분자의 나노 크기의 섬유를 만드는 기술로 널리 사용되어졌으며, 제작된 나노섬유는 그 높은 표면적과 형태학적 특성때문에 조직재생 공학분야에서 많이 사용되어져 왔다. 본 연구에서는 기존의 전기방사공정을 개선한 복합전기장을 이용하여 생분해성/생체적합성 poly(${\varepsilon}$-caprolactone) (PCL) 마이크로/나노섬유를 제작하였고, 기존의 나노섬유의 배열성보다 제어가 가능한 배열성을 갖는 공정시스템을 통하여 보다 우수한 배열성을 갖는 PCL 나노섬유를 제작하였다. 고배열된 PCL 나노섬유는 신경세포 재생을 위한 세포담체로서의 가능성을 확인하고자 신경세포(PC-12)를 배양하였으며 그 결과 높은 배열성을 갖은 PCL 나노섬유 매트에서 신경세포의 배열성이 얻어짐을 확인하였다.

• 한국응용과학기술학회지
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• 제35권4호
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• pp.1197-1205
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• 2018

자외선차단 화장품은 기능성 화장품 중의 하나로서, 유 무기 자외선차단물질이 함유되어 있다. 무기계 자외선차단제는 주로 산화아연, 이산화티탄 등이 있다. 무기계 자외선차단제는 입자의 지름이 60 ~ 100 nm로 자외선 A, B의 차단능이 좋은 것으로 알려져 있다. 또한자외선을 포함한 태양광선에 대해 비활성이 크고 안전성이 우수하다. 그리고 유기계 자외선차단제처럼 피부에 흡수 또는 축적되지 않으므로 피부자극이나 알레르기를 유발하지 않는다. 본 연구에서는 판상 무기안료인 마이카, 자외선차단 효과를 갖는 이산화티탄 나노입자, 소수성 실리카를 각각 계면활성제로 표면처리 하였고, 각 물질의 전하 차이에 따른 비화학적인 상호 인력 작용에 의해 마이카에 이산화티탄 나노입자, 실리카를 물리적으로 흡착시켰다. 이후, 소수성 표면처리제인 실란을 표면처리 하여 소수성을 갖는 자외선 차단 판상 마이카 복합체를 제조하였다. 자외선 차단 판상 마이카 복합체는 일반적인 나노입자 이산화티탄의 응집성을 개선하고 균일한 분산에 따른 자외선차단 효과가 증대되었으며, 소수성으로 표면처리를 하여 화장품 제형에서의 분산안정성을 크게 개선할 수 있었다. 안료의 표면전하는 제타전위로 평가하였으며, 제조된 자외선차단 마이카 복합체의 특성 평가는 FE-SEM, XRD, FT-IR, UV-VIS 등으로 확인하였다.

• 분석과학
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• 제22권3호
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• pp.247-253
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• 2009

단결정의 실리콘 웨이퍼를 hydrofluoric acid와 ethyl alcohol이 혼합된 용액에 담궈 적정한 전류를 흘려주면 웨이퍼 표면에 수많은 pore를 형성하면서 에칭되어진다. 이러한 pore의 형태와 porosity는 전류 값과 에칭 시간 및 주기를 변화시켜 쉽게 조절할 수 있는데, 이렇게 제작된 다공성 실리콘은 수백 $m^2/cm^3$의 큰 표면적을 가지게 된다. 이때 sin 파와 같은 모양으로 시간대별 가해지는 전류 밀도를 다르게 해주어 pore안쪽의 모양을 변화시켜 주어 가시광선 영역에서 하나의 spectrum을 나타나게 되는 rugate 박막을 제작 한다. 본 연구에서는 법과학적인 목적으로 코드화된 다공성 실리콘의 rugate film을 이용하여 nano particle을 제작한 다음 이 입자들을 페인트에 혼합, 차량에 도포하고, 회수 후에 이를 확인할 수 있는지 조사하였다. 본 연구에서는 또 다양하게 가해지는 전류 값을 변경 또는 혼합하여 다공성 실리콘에 다양한 코드화를 시도하였으며, 사고 시 탈착한 페인트에서 다공성 실리콘 nano particle을 회수 하기위해 다공성 실리콘 안에 magnetite를 삽입하여 자석을 이용한 미량 나노입자 시료를 응집시켜 스펙트럼을 확인하였다.