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排序方式: 共有241条查询结果,搜索用时 15 毫秒
1.
Seung Han Ryu Seil Kim Young-Tae Kwon Young Ki Park Sung-Oong Kang Hong-Baek Cho Yong-Ho Choa 《应用聚合物科学杂志》2020,137(8):48390
Here, we report a facile approach to electrostatically couple the surface charges of graphite nanoplate (GNP) fillers and poly(methyl methacrylate) (PMMA) polymer particles using ethylene maleic anhydride (EMA) copolymer as an electrostatic coupling agent. Our strategy involved switching the intrinsic repulsive electrostatic interactions between the directly exfoliated GNPs fillers and the PMMA particles to attractive electrostatic surface interactions for preparing core(PMMA)-shell (GNP) precursor in order to optimizing 3-dimensionally dispersed polymer nanocomposite. As a result, the electrical conductivity of the composites dramatically increased by a factor of 16.7 in the EMA-coupled GNP/PMMA composites compared with that of the EMA-free GNP/PMMA composites. In addition, the percolation threshold was also notably reduced from 0.32 to 0.159 vol% after electrostatic coupling of the GNPs fillers and PMMA particles. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48390. 相似文献
2.
Sung-Hoon An U-Yeol Park Kyung-In Kang Moon-Young Cho Hun-Hee Cho 《Canadian Metallurgical Quarterly》2007,21(4):259-264
Total conceptual cost estimates and the assessment of the quality of these estimates are critical in the early stages of a building construction project. In this study, the support vector machine (SVM) model for assessing the quality of conceptual cost estimates is proposed, and the application of SVM in construction areas is investigated. The results show that the SVM model assessed the quality of conceptual cost estimates slightly more accurately than the discriminant analysis model. This shows that using the SVM has potential in construction areas. In addition, the SVM model can assist clients in their evaluation of the quality of the estimated cost and the probability of exceeding the target cost, and in their decision on whether or not it is necessary to seek a more accurate estimate in the early stages of a project. 相似文献
3.
En-Hai Sun Yong-Ho Choa Tohru Sekino Tomohiko Adachi Koichi Niihara 《Materials Research Innovations》2002,6(3):105-111
Cordierite/ZrO2 composites with 5 to 25 wt% ZrO2 were fabricated by conventional powder mixing and pressureless sintering method. Their densification behavior, microstructure,
mechanical and thermal properties were studied. By dispersing 25 wt% (9.57 vol%) ZrO2, densified cordierite/ZrO2 composite with a relative density of 98.5% was obtained at an optimum sintering condition of 1440 °C and 2 h. ZrO2 particles were homogenously dispersed within matrix grains and at the grain boundaries. The intragranular particles were
finer than 100 nm and the intergranular particles were coarser. Both fracture strength and toughness could be enhanced more
than two times higher, compare to those of monolithic cordierite, by dispersing 25 wt% ZrO2 into the cordierite matrix. The toughening mechanism in the present composites was mainly attributed to martensitic transformation
due to ZrO2 dispersion.
Electronic Publication 相似文献
4.
D.L. Butler P.S. Cho M.W. Chbat J. Goldhar F.-S. Choa G.L. Burdge 《Photonics Technology Letters, IEEE》1996,8(6):779-781
We demonstrate stable operation of a NOLM using orthogonally polarized control and signal beams in nonpolarization-preserving, single-mode fiber. The NOLM can transcribe data from an optically incoherent input at one wavelength to a coherent output over a range of wavelengths. Operation of the NOLM without tuning for the input bit rate is possible over a range of bit rates from less than 1 Gb/s to more than 50 Gb/s. 相似文献
5.
Hyuk-Jin Kang Hyung-Jung KimJi-Seok Kim Woon-Yong ChoiWon-Shik Chu Sung-Hoon Ahn 《Robotics and Computer》2010
A light guide panel (LGP) is an element of the liquid crystal display (LCD) back light unit (BLU), which is used for display devices. In this study, the laser marking process is applied to the fabrication of light guide panels as the new fabrication process. In order to obtain a light guide panel which has high luminance and uniformity, four principal parameters such as power, scanning speed, ratio of line gap, and number of line were selected. A web-based design tool was developed to generate patterns of light guide panel via the network, and the tool may assist the designer to develop various prototype patterns. Topcon-BM7 was used for luminance measurement of each specimen with 100 mm×100 mm area. By Taguchi method, optimized levels of each parameter were found, and luminance of 3523 cd/cm2 and uniformity of 92% were achieved using the laser machined BLU. 相似文献
6.
7.
Jitendra Kumar Pandey Hitoshi Takagi Antonio Norio Nakagaito Daulat Ram Saini Sung-Hoon Ahn 《Composites Part B》2012,43(7):2822-2826
Biopolymer based composites have been employed in numerous applications with increasing interest not only due to renewable, eco-friendly nature, but also because of the flexibility in processing conditions and competitive cost of their end products. The conductive materials from biopolymers have been found applicable in robots, medical imaging, sensitive membranes, actuators, visual displays, electronic wiring and shielding, and components in batteries. Cellulose is one of the most abundant biopolymers in the nature, which has received special attention for development of conducting materials due to biocompatibility for protein and drug immobilization and ability to form the composites with synthetic polymers. The present review is aimed to provide concisely the current status in this field of conducting composites from cellulose, with brief discussions of associated problems and future applications. 相似文献
8.
Enhancement of electroconductivity of polyaniline/graphene oxide nanocomposites through in situ emulsion polymerization 总被引:1,自引:0,他引:1
Syed Muhammad Imran YouNa Kim Godlisten N. Shao Manwar Hussain Yong-ho Choa Hee Taik Kim 《Journal of Materials Science》2014,49(3):1328-1335
The present study introduces a systematic approach to disperse graphene oxide (GO) during emulsion polymerization (EP) of Polyaniline (PANI) to form nanocomposites with improved electrical conductivities. PANI/GO samples were fabricated by loading different weight percents (wt%) of GO through modified in situ EP of the aniline monomer. The polymerization process was carried out in the presence of a functionalized protonic acid such as dodecyl benzene sulfonic acid, which acts both as an emulsifier and protonating agent. The microstructure of the PANI/GO nanocomposites was studied by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV–Vis spectrometry, Fourier transform infrared, differential thermal, and thermogravimetric analyses. The formed nanocomposites exhibited superior morphology and thermal stability. Meanwhile, the electrical conductivities of the nanocomposite pellets pressed at different applied pressures were determined using the four-probe analyzer. It was observed that the addition of GO was an essential component to improving the thermal stability and electrical conductivities of the PANI/GO nanocomposites. The electrical conductivities of the nanocomposites were considerably enhanced as compared to those of the individual PANI samples pressed at the same pressures. An enhanced conductivity of 474 S/m was observed at 5 wt% GO loading and an applied pressure of 6 t. Therefore, PANI/GO composites with desirable properties for various semiconductor applications can be obtained by in situ addition of GO during the polymerization process. 相似文献
9.
Eun-Ji Choi Eun-Hye Ka Cha-Young Jo Sung-Hoon Jo Emmanouil Apostolidis Mee-Sook Lee Hae-Dong Jang Young-In Kwon 《Food science and biotechnology》2014,23(3):791-797
Antibacterial and antioxidant activities of wheat seed ethyl acetate extracts for Jokyoung (JK), Dark northern spring (DNS), Keumkang (KK), Woori (WR), and Winter wheat (WW) were investigated. Antibacterial activities were evaluated in vitro against the common food and cosmetic industry contaminants Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus using well diffusion assays. WW had the highest inhibitory activity against all tested strains, with S. aureus being the most sensitive strain. The minimum inhibitory concentration (MIC) values of WW and WR against S. aureus were 0.50 and 1.25 mg/mL, respectively. The 2,6-dimethoxy-1,4- benzoquinone (DMBQ) content was measured using HPLC. The antibacterial activities of wheat seed extracts were correlated with the total phenolic contents (Pearson’s correlation coefficient=0.994), with the ABTS radical scavenging activity (0.978), and with the DMBQ content (0.968). WW and WR have potential for use as natural antimicrobials for prevention of food and cosmetics spoilage. 相似文献
10.
Nano to micro-sized patterns were formed on a flexible polymer substrate using a flexible UV imprint stamp. A 6 in. diameter flexible UV nanoimprint template was fabricated using PVC hot embossing and DLC coating. Using the UV nanoimprint process with the DLC coated PVC template, nano to micro-sized patterns were clearly formed on the flexible PET substrate without a residual layer, due to the antistiction properties and high mechanical hardness of the DLC coating. By depositing a Cr layer on the imprinted resist pattern and lifting it off, Cr metal patterns were fabricated on the PET substrate. 相似文献