• 센서학회지
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• 제21권1호
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• pp.13-20
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• 2012

Due to its high conductivity, pyrylium has been frequently used in electron transfer reactions or in the synthesis of various organic materials. It has also been used as a sensor material. Traditionally, the compounds have been synthesized using various methods; mostly in a multiple steps. In this study, two pyrylium salts, 2, 6-di-(4'-methylphenyl) pyrylium fluoroborate and perchlorate were synthesized. The synthesis of these products was confirmed by 1H-NMR, LC/TOF-MS and FT-IR analyses while their photo-properties were analyzed using UV/VIS spectrophotometry. In addition, the electron transfer capacities of the salts were analyzed with a conductivity meter, it was found that their electron conductivities were high. When the synthesized compounds were dissolved in acetone, a green fluorescent material was observed to form. The fluorescent material can be used as a sensitizer in the electrical industry.

• Smart Structures and Systems
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• 제12권5호
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• pp.579-594
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• 2013

A new enthalpy - based procedure for the homogenization of the electromechanical material parameters of composite piezoelectric modules with integrated electrodes is presented. It is based on a finite element (FE) modeling of the latter's representative volume element (RVE). In contrast to most previously published homogenization approaches that are based on averaged quantities, the presented method uses a direct evaluation of the electromechanical enthalpy. Hence, for the linear orthotropic piezoelectric composite behavior full set of elastic, piezoelectric, and dielectric material parameters, 17 load cases (LC) are used where each load case leads directly to one material parameter. This gives the possibility to elaborate a very strict and easy to program processing. In conjunction with the 17 LC, the enthalpy - based homogenization is particularly suitable for laminated composite piezoelectric modules with integrated electrodes. In this case, the electric load has to be given at the electrodes rather than at the RVE FE model boundaries. The proposed procedure is validated through its comparison to literature available results on a classical 1-3 piezoelectric micro fiber (longitudinally polarized) reinforced composite and a $d_{15}$ shear piezoelectric macro-fiber (transversely polarized) composite module.

• 한국전기전자재료학회논문지
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• 제17권7호
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• pp.760-763
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• 2004

We studied the nematic liquid crystaL(NLC) aligning capabilities using the new alignment material of a nitrogenated diamond-like carbon(NDLC) thin film. The NDLC thin film exhibits high electrical resistivity and thermal conductivity that are similar to the properties shown by diamond-like carbon (DLC) thin films. The diamond-like properties and nondiamond-like bonding make NDLC an attractive candidate for applications. A high pretilt angle of about 9.9$^{\circ}$ by ion beam(IB) exposure on the NDLC thin film surface was measured. A good LC alignment is achieved by the IB alignment method on the NDLC thin films surface at annealing temperature of 200 $^{\circ}C$. The alignment defect of the NLC was observed above annealing temperature of 250 $^{\circ}C$. Consequently, the high pretilt angle and the good LC alignment by the IB alignment method on the NDLC thin film surface can be achieved.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 제6회 학술대회 논문집 일렉트렛트 및 응용기술연구회
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• pp.23-26
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• 2004

We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of a Carbon Nitride (NDLC) thin film. NDLC thin film exhibits high electrical resistivity and thermal conductivity that are similar to the properties shown by diamond-like carbon (DLC) thin films. The diamond-like properties and nondiamond-like bonding make NDLC an attractive candidate for applications. A high pretilt angle of about $9.9^{\circ}$ by ion beam (IB) exposure on the NDLC thin film surface was measured. A good LC alignment is achieved by the IB alignment method on the NDLC thin film surface at annealing temperature of $200^{\circ}C$. The alignment defect of the NLC was observed above annealing temperature of $250^{\circ}C$. Consequently, the high pretilt angle and the good LC alignment by the IB alignment method on the NDLC thin film surface can be achieved.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.394-395
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• 2007

In order to make full color cholesteric displays, color filter-less R, G, B sub-pixel structured cholesteric LC cells have been studied. To make R, G, B colors, UV induced pitch variant chiral dopant was added to cholesteric LC mixtures. The concentration of the photo-sensitive chiral dopant was adjusted so that the initial state showed blue color and the color was changed from blue to green and red with increase of UV irradiation to the cholesteric cells. To prevent the mixing of R, G, B reflective sub-pixel liquid crystals, separation walls were formed using negative photo resister in boundary area between sub-pixels. Through the optimization of the material concentrations and UV irradiation condition, vivid R, G, B colors were achieved.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.185-188
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• 2005

We synthesized the two types of photoalignment material of high thermal resistance with hydroxyl aromatic polyimide, and studied the liquid crystal (LC) aligning capabilities on the photopolymer layers. Also, electro-optical (EO) performances for the twisted-nematic (TN)-liquid crystal display (LCD) photoaligned with linearly polarized UV exposure were investigated. A good LC alignment with UV exposure on the two types of photopolymer surface can be obtained. The Voltage-transmittance (V-T) curve in the photoaligned TN cell with UV exposure was different from two type. The response time of photoaligned TN cell was measured about 21 ms in two alkyl chain and about 15ms in four alkyl chain.

• 대한화장품학회지
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• 제48권4호
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• pp.365-372
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• 2022

셀로비오스(cellobiose)는 식물 등에 널리 분포하는 셀롤로오스의 분해 과정에서 생성되는 이당류이다. 환원당인 셀로비오스는 2 개의 β-1,4 결합으로 결합한 구조를 가지며, 식물 등에 존재하는 천연물로서, 건강식품이나 식품의 감미료, 화장품 원료, 의약품 원료로서 활용되어지고 있다. 본 연구에서는 다양하게 유용될 셀로비오스를 기능성 화장품인 미백 화장품 소재로서의 가능성을 확인하고자, 자가포식 활성화 및 멜라닌 생성저해 효능을 검토하였다. 인간 유래 멜라닌 생성 세포로 알려진 MNT-1 세포에서 셀로비오스의 농도에 따른 독성 실험을 진행한 결과 20 mg/mL이하에서 세포독성이 없음을 확인하였고, 공초점 현미경을 통해 셀룰비오스 처리에 따른 자가포식 표지자인 microtubule-associated protein 1 light chain 3 (LC3) puncta의 증가가 확인되었다. 또한 LC3의 형태가 LC3-I에서 LC3-∏로 변환됨을 확인하였으며, 농도와 시간에 따라 LC3-II양이 증가하는 것을 확인하였다. 셀로비오스를 동일 세포에서 20 mg/mL 농도로 7 일간 처리하여 멜라닌 생성량을 분석한 결과, 50% 이상 멜라닌 생성 감소를 확인하였다. 추가적으로, 멜라닌 생성 관련 단백질TYR 및 TYRP1의 발현량을 western blot법을 이용하여 분석한 결과, 농도의존적으로 발현이 저해되어 멜라닌 생성이 감소함을 확인하였다. 이러한 연구 내용을 기반을 토대로 셀로비오스를 함유한 화장품 크림제형을 확보하여 4 주 동안 제형의 변화를 확인 해본 결과 성상이 고온에서 액채형태로 변화하였지만 pH는 변화하지 않았음을 확인하였다. 결론적으로, 자가포식 활성화 및 멜라닌 생성 억제 과정에 셀로비오스가 관여함을 확인하였으며, 이를 통해 미백 화장품 소재로서의 활용 가능성을 제안하고자 한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.430-430
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• 2007

In general, polyimides (PIs) are used in liquid crystal displays (LCDs) as alignment layer of liquid crystals (LCs). Up to date, the rubbing alignment technique has been widely used to align liquid crystals on the PI surface, which is suitable for mass-production of LCDs because of its simple process and high productivity. However, this method has some disadvantages. Rubbed PI surfaces include the debris left by the cloth and the generation of electrostatic charges during rubbing process. Therefore, rubbing-free techniques for LC alignment are strongly required in LCD technology. In this experiment, PI was uniformly coated on indium-tin-oxide electrode substrates to form LC alignment layers using a spin-coating method and the PI layers were subsequently imidized at 433 K for 1 h. The thickness of the PI layer was set at 50 nm. The LC alignment layer surfaces were exposed to an $Ar^+$ ion-beam under various ion-beam energies. The antiparallel cells and twisted-nematic (TN) cells for the measurement of pretile angle and electro-optical characteristics were fabricated with the cell gap of 60 and $5\;{\mu}m$, respectively. The LC cells were filled with nematic LC (NLC, MJ001929, Merck) and were assembled. The NLC alignment capability on ion-beam-treated PI was observed using photomicroscope and the pretilt angle of the NLC was measured by the crystal-rotation method at room temperature. Voltage-transmittance (V-T) and response time characteristics of the ion-beam irradiated TN cell were measured by a LCD evaluation system.

• Asian Pacific Journal of Cancer Prevention
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• 제14권6호
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• pp.3975-3978
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• 2013

Background: Proteases play a regulatory role in a variety of pathologies including cancer, pancreatitis, thromboembolic disorders, viral infections and many others. One of the possible strategies to combat these pathologies seems to be the use of protease inhibitors. LC-pi I, II, III and IV (Lavatera cashmerian-protease inhibitors) have been found in vitro to strongly inhibit trypsin, chymotrypsin and elastase, proteases contributing to tumour invasion and metastasis, indicated possible anticancer effects. The purpose of this study was to check in vitro anticancer activity of these four inhibitors on human lung cancer cell lines. Material and Methods: In order to assess whether these inhibitors induced in vitro cytoxicity, SRB assay was conducted with THP-1 (leukemia), NCIH322 (lung) and Colo205, HCT-116 (colon) lines. Results: LC-pi I significantly inhibited the cell proliferation of all cells tested and also LC-pi II was active in all except HCT-116. Inhibition of cell growth by LC-pi III and IV was negligible. $IC_{50}$ values of LC-pi I and II for NCIH322, were less compared to other cell lines suggesting that lung cancer cells are more inhibited. Conclusion: These investigations might point to future preventive as well as curative solutions using plant protease inhibitors for various cancers, especially in the lung, hence warranting their further investigation.

• 한국축산식품학회지
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• 제35권4호
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• pp.466-472
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• 2015

A rapid and simple analytical method, using liquid chromatography tandem mass spectrometry (LC-MS/MS), was developed to detect myo-inositol (MI) in infant formulas. For protein removal: acid hydrolysis and lipid removal through organic solvent extraction. The operating conditions for instrumental analysis were determined based on previously reported analogous methods that used LC-MS/MS. Quantitative analysis was used for the detection limit test, infant formula recovery test, and standard reference material (SRM) 1849a to verify the validity of our LC-MS/MS analytical method, which was developed to quantify MI. For validation, the results of our method were compared with the results of quantitative analyses of certified values. The test results showed that the limit of detection was 0.05 mg/L, the limit of quantitation was 0.17 mg/L, and the method detection limit was 17 mg/kg. The recovery test exhibited a recovery between 98.07-98.43% and a relative standard deviation between 1.93-2.74%. Therefore, the result values were good. Additionally, SRM 1849a was measured to have an MI content of 401.84 mg/kg and recovery of 98.25%, which is comparable to the median certified value of 409 mg/kg. From the aforementioned results, we judged that the instrumental analysis conditions and preparation method used in this study were valid. The rapid analytical method developed herein could be implemented in many laboratories that seek to save time and labor.