• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.437-438
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• 2005

A polymer stabilization method is employed to reduce the transition time from field-induced homeotropic(H) state to reflecting planar(P) state in the cholesteric liquid crystal(ChLC) display. To stabilize ChLC by polymer, we mixed ChLC with diacrylate of 2 $wt%{\sim}6$ wt%. Two samples were made with different method of stabilization. For one sample the diacrylate of 2 wt% was polymerized with the ChLC in P state, while for the other sample diacrylate of 16 wt% was polymerized with ChLC in H state. In the former case, the transition time was 1000 times faster then those in the pure sample. In the latter sample, the transition time was 1700 times faster than those in pure ChLC sample.

• 한국재료학회지
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• 제10권5호
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• pp.350-353
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• 2000

강유전성 액정 분자 배향을 위해 열방성 고분자 액정물질을 배향막으로 사용하고 그표면 morphology를 AFM(Atomic Forced Microscope)으로 관찰한 결과 잘 배향된 sample cell에서도 microgroove 구조가 나타나지 않았음을 관찰하였다. 잘 배향된 sample cell 23:1의 contrast ratio를 보이면서 memory 효과를 나타내었다. 또한 20V의 AC field로 안정화시키자 전형적인 stripe-shaped 무늬가 나타났다.

• 한국기계연구소 소보
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• 통권13호
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• pp.15-25
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• 1984

The infrared spectra were determined to discover the characteristics and properties of poff-, PV-, and cc-samples, and studied influence on the formation of mesophase or liquid crystal. The experimental results were as follows; a) Samples with long aliphatic side chain appear cracking texture on temperature forming liquid crystal. b) The fine isotropic microstructure appears in a heterogeneous material containing sulfur, 7.18 w%. c) In the size of molecular weight the lighter than 500 form liquid crystal. d) When poff-sample was treated at $400^{\circ}C$ aliphatic hydrocabon compounds decrease, presented well-oriented bulk liquid crystal.

• Transactions on Electrical and Electronic Materials
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• 제13권5호
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• pp.221-224
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• 2012

The present paper reports the comparative optical behavior of a pure nematic mixture E-24 and its anthraquinone dye doped sample. The variation in the ordinary and extraordinary refractive index ($n_o$, $n_e$) of the pure and dye doped samples with temperature has been discussed and it has been found that doped sample have a less refractive index compared to the pure sample. The variation in the order parameter for pure and doped samples with temperature has been discussed and it has been seen that the doped sample has a higher order parameter; the possible reasons have been discussed. The variations in birefringence and optical transmittance have also been presented here.

• 대한전기학회논문지
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• 제43권6호
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• pp.958-964
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• 1994

To study on the superconducting properties with cooling conditions, silver-sheathed Bi-Pb-Sr-Ca-Cu-O wires fabricated by the powder-in-tube method. The wires cooled down in the furnace, air and liquid NS12T after sintering at 840$^{\circ}C$ Critical current density of sample cooled in the furnace is 5.1${\times}$10S03TA/cmS02T and sample cooled in the air is 40A/cmS02T at 77K, zero magnetic field. The latter is very low critical current density of Bi system. 2223 high-Tc superconducting phase of sample cooled in the air was distroyed. Properties of sample cooled down in the liquid nitrogen is the same as cooled in the furnace.

• 한국해양환경ㆍ에너지학회지
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• 제3권3호
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• pp.34-40
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• 2000

지용성 용존 유기물을 해수로부터 효율적으로 추출할 수 있는 고체상 추출 (solid phase extraction)장치를 새로이 고안하였다. 본 장치는 octadecyl silane (ODS) cartridge와 압력 평형 마개, 96 multifolder, 아스피레타 형 진공 펌프로 구성하였다. 본 장치는 기존의 액체-액체 추출법보다 회수 효율은 1.4 배 이상 증대시켰으며, 최소 시료량을 8 배 이상 감소 시켰다. 따라서 용매의 사용을 5 배 이상 감소시킬 수가 있으므로 나중에 사용된 용매를 제거하는 노력도 크게 감소시켰다. 뿐만 아니라 96 개의 시료(각 1ℓ)를 동시에 처리할 수 있으므로 지용성 용존 유기물의 추출 과정을 반자동화시킨 획기적인 장치이다. 본 장치를 통하여 황해 해수 시료에서 추출된 용존 탄화수소의 정성 및 정량 분석 결과 본 장치가 효율성과 신뢰성에서 기존의 액체-액체 추출법을 대체할 수 있을 것으로 사료된다.

• 한국기계가공학회지
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• 제19권10호
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• pp.1-7
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• 2020

In this study, a multichannel gas-liquid microextraction system is designed by integrating the automatic elution of extraction line and multichannel gas-purging liquid phase microextraction. The system uses an injection pump and inert gas to push the extraction solvent to a sample bottle of a gas-phase color autosampler and then implements multichannel gas-liquid microextraction and gas chromatography-mass spectrometry. The system also employs a three-way integrated micro-high-temperature heater, syringe pump, and microflow controller to realize the simultaneous processing of multiple groups of samples, thus improving the sample pretreatment speed and reproducibility and reducing human error. Autoinjection experiments were implemented with polycyclic aromatic hydrocarbon standard samples. The experiments show that the average recovery rate of the system exceeds 70%, and the relative standard among the channels is less than 15%.

• 한국레이저가공학회지
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• 제11권1호
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• pp.12-18
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• 2008

Laser micromachining is a promising technique to fabricate the micro-scale devices. However, there remains important challenges to reducethe redeposition of ablated materials around the laser irradiated zone and to get a smooth surface, especially for metal and semiconductor materials. To achieve the high-quality micromachined devices, various methods have been developed. Liquid-assisted micromachining can be a good solution to overcome the previously mentioned problems. During the laser ablation process, the liquid around the solid sample dramatically changes the ablation characteristics, such as ablation rate, surface profile, formation of debris, and so on. In this investigation, we conducted the laser micromachining of Si in various liquid environmental conditions, such as liquid types, liquid thickness. In addition, using nanoscale time-resolved shadowgraphy technique, we observed the ablation process in liquid environments to understand the mechanism of liquid-assisted laser micromachining.

• Asian Pacific Journal of Cancer Prevention
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• 제15권17호
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• pp.7085-7090
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• 2014

Objective: To make the clinical evaluation of a solid-state human papillomavirus (HPV) sampling medium in combination with an economical HPV testing method ($careHPV^{TM}$) for cervical cancer screening. Methods: 396 women aged 25-65 years were enrolled for cervical cancer screening, and four samples were collected. Two samples were collected by woman themselves, among which one was stored in DCM preservative solution (called "liquid sample") and the other was applied on the Whatman Indicating FTA $Elute^{(R)}$ card (FTA card). Another two samples were collected by physician and stored in DCM preservative solution and FTA card, respectively. All the samples were detected by $careHPV^{TM}$ test. All the women were administered a colposcopy examination, and biopsies were taken for pathological confirmation if necessary. Results: FTA card demonstrated a comparable sensitivity of detecting high grade Cervical Intraepithelial Neoplasia (CIN) with the liquid sample carrier for self and physician-sampling, but showed a higher specificity than that of liquid sample carrier for self-sampling (FTA vs Liquid: 79.0% vs 71.6%, p=0.02). Generally, the FTA card had a comparable accuracy with that of Liquid-based medium by different sampling operators, with an area under the curve of 0.807 for physician &FTA, 0.781 for physician &Liquid, 0.728 for self & FTA, and 0.733 for self &Liquid (p>0.05). Conclusions: FTA card is a promising sample carrier for cervical cancer screening. With appropriate education programmes and further optimization of the experimental workflow, FTA card based self-collection in combination with centralized $careHPV^{TM}$ testing can help expand the coverage of cervical cancer screening in low-resource areas.

• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1011-1015
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• 2014

Octadecyl-modified graphene (graphene-C18) was fabricated and used as adsorbent in hollow fiber liquid phase microextraction (HF-LPME) for the first time. The extraction performance of graphene-C18 reinforced HF-LPME was evaluated using chlorophenols as model analytes. The factors affecting the extraction efficiency, such as extraction time, pH of the sample solution, agitation rate, the concentration of graphene-C18 and salt addition were optimized. After the graphene-C18 reinforced HF-LPME of the chlorophenols from honey sample, the analytes were separated and determined by high-performance liquid chromatography. The linearity was observed in the range of 5.0-200.0 ng $g^{-1}$ for 2-chlorophenol and 3-chlorophenol, and 2.0-200.0 ng $g^{-1}$ for 2,3-dichlorophenol and 3,4-dichlorophenol, respectively. The limits of detection (S/N = 3) of the method were lower than 1.5 ng $g^{-1}$. The recoveries of the method were between 88% and 108%. The method is simple, sensitive and has been resoundingly applied to analysis of chlorophenols in honey samples.