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41.
42.
Chang Won Ahn Hee Sung Kim Won Seok Woo Sung Sik Won Hae Jin Seog Song A Chae Bong Chan Park Ki Bong Jang Yun Po Ok Hyon Ho Chong Ill Won Kim 《Journal of the American Ceramic Society》2015,98(6):1877-1883
We investigated the influence of CuO amount (0.5–3.0 mol%), sintering temperature (900°C–1000°C), and sintering time (2–6 h) on the low‐temperature sintering behavior of CuO‐added Bi0.5(Na0.78K0.22)0.5TiO3 (BNKT22) ceramics. Normalized strain (Smax/Emax), piezoelectric coefficient (d33), and remanent polarization (Pr) of 1.0 mol% CuO‐added BNKT22 ceramics sintered at 950°C for 4 h was 280 pm/V, 180 pC/N, and 28 μC/cm2, respectively. These values are similar to those of pure BNKT22 ceramics sintered at 1150°C. In addition, we investigated the performance of multilayer ceramic actuators made from CuO‐added BNKT22 in acoustic sound speaker devices. A prototype sound speaker device showed similar output sound pressure levels as a Pb(Zr,Ti)O3‐based device in the frequency range 0.66–20 kHz. This result highlights the feasibility of using low‐cost multilayer ceramic devices made of lead‐free BNKT‐based piezoelectric materials in sound speaker devices. 相似文献
43.
Template‐Directed Directionally Solidified 3D Mesostructured AgCl–KCl Eutectic Photonic Crystals
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44.
Photonic Crystals: Template‐Directed Directionally Solidified 3D Mesostructured AgCl–KCl Eutectic Photonic Crystals (Adv. Mater. 31/2015)
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45.
Prakash Parthasarathy Hang Seok Choi Hoon Chae Park Jae Gyu Hwang Ho Seong Yoo Byeong-Kyu Lee Mukesh Upadhyay 《Korean Journal of Chemical Engineering》2016,33(8):2268-2286
Waste tyres have become a grave concern as their accumulation is aggregating every year. Not only the size of waste tyre has to be reduced, but also some useful energy has to be recovered out of it as the world badly requires energy from alternate sources. Pyrolysis is one such method to extract energy potential products from waste tyres. It is extensively used to generate carbon black (solid product), tyre-oil (liquid product) and syngas (gas product) from waste tyres. In that connection, this article discusses the effect of various parameters on the product composition of pyrolysis of waste tyres. The current usage of pyrolysis products and their typical characteristics are also discussed in this critique. Of late, extraction of high value added products, such as activated carbon from carbon black, and limonene from tyre-oil is gaining attention. The article also throws some light on the application and generation routes of activated carbon and limonene from waste tyres. 相似文献
46.
Polyacrylonitrile solution homogeneity study by dynamic shear rheology and the effect on the carbon fiber tensile strength
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Bradley A. Newcomb Prabhakar V. Gulgunje Yaodong Liu Kishor Gupta Manjeshwar G. Kamath Chandrani Pramanik Sushanta Ghoshal Han Gi Chae Satish Kumar 《Polymer Engineering and Science》2016,56(3):361-370
Poly(acrylonitrile‐co‐methacrylic acid) (PAN‐co‐MAA)/N,N‐dimethylformamide (DMF) solutions were prepared and dynamic shear rheology of these solutions were investigated. With increasing stirring time up to 72 h at 70°C, the polymer solution became less elastic (more liquid‐like) with a ~60% reduction in the zero‐shear viscosity. Relaxation spectra of the PAN‐co‐MAA/DMF solutions yield a decrease in relaxation time (disentanglement time, τd), corresponding to an about 8% decrease in viscosity average molecular weight. The log‐log plot of G′ (storage modulus) versus G″ (loss modulus) exhibited an increase in slope as a function of stirring time, suggesting that the molecular level solution homogeneity increased. In order to study the effect of solution homogeneity on the resulting carbon fiber tensile strength, multiple PAN‐co‐MAA/DMF solutions were prepared, and the precursor fibers were processed using gel‐spinning, followed by continuous stabilization and carbonization. The rheological properties of each solution were also measured and correlated with the tensile strength values of the carbon fibers. It was observed that with increasing the slope of the G′ versus G″ log‐log plot from 1.471 to 1.552, and reducing interfilament fiber friction during precursor fiber drawing through the addition of a fiber washing step prior to fiber drawing, the carbon fiber strength was improved (from 3.7 to 5.8 GPa). This suggests that along with precursor fiber manufacturing and carbonization, the solution homogeneity is also very important to obtain high strength carbon fiber. POLYM. ENG. SCI., 56:361–370, 2016. © 2016 Society of Plastics Engineers 相似文献
47.
Ji Eun Lee Hoon Chae Park Hang Seok Choi Seung Yeon Cho Tae Young Jeong Sung Cheoul Roh 《Korean Journal of Chemical Engineering》2016,33(3):782-794
Numerical simulations were conducted using computational fluid dynamics to evaluate the effect of ventilation conditions on radon (222Rn) reduction performance in a residential building. The results indicate that at the same ventilation rate, a mechanical ventilation system is more effective in reducing indoor radon than a natural ventilation system. For the same ventilation type, the indoor radon concentration decreases as the ventilation rate increases. When the air change per hour (ACH) was 1, the indoor radon concentration was maintained at less than 100 Bq/m3. However, when the ACH was lowered to 0.01, the average indoor radon concentration in several rooms exceeded 148 Bq/m3. The angle of the inflow air was found to affect the indoor air stream and consequently the distribution of the radon concentration. Even when the ACH was 1, the radon concentrations of some areas were higher than 100 Bq/m3 for inflow air angles of 5° and 175°. 相似文献
48.
Pamidimarri D.V.N. Sudheer Yokimiko David Cheol Gi Chae You Jin Kim Mary Grace Baylon Kei-Anne Baritugo Tae Wan Kim Min-Sik Kim Jeong Geol Na Si Jae Park 《Korean Journal of Chemical Engineering》2016,33(10):2788-2801
Coal, the most primitive fossil fuel, has been exploited for ages, and reserves dictate the economies of many countries. Presently, most energy is generated by direct combustion, raising concerns over global warming. Biological pretreatment of fossil resources and generation of alternative green energy can address the environmental issues associated with global coal utilization. Biological coal treatment can produce industrially important chemicals and bio-methane by employing microorganisms able to depolymerize/degrade coal. This review discusses current advances in microbial coal conversion, such as the efforts made to comprehend microbial processes, significant outputs of coal conversion, principle components responsible for coal conversion, and factors affecting the biological processes to convert coal. Development of these biological processes can be a stepping stone for greener coal; however, integration of multidisciplinary technologies is needed to increase the efficiency of economic coal utilization and production of economically and industrially feasible biomethane. 相似文献
49.
Seok-June Chae Dae-Su Kim Hero Kim Su-Hwan Go Sun-Woo Kim Eun-Ji Kim Jae-Min Eum In-Su Kim Sahn Nahm 《Journal of the American Ceramic Society》2022,105(2):1185-1197
0.97(Na0.5-xLixK0.5)(Nb0.89Sb0.11)O3-0.03CaZrO3 [(N0.5-xLxK)(NS)-CZ] piezoceramic (x = 0.325) has a pseudocubic-tetragonal-orthorhombic (PC-T-O) multi-structure. The PC structure formed in this piezoceramic was identified as the R3m rhombohedral structure. This piezoceramic showed the large piezoelectric charge constant (d33) of 515 pC/N due to the PC-T-O multi-structure. The NaNbO3 (NN) templates were used to texture the (N0.5-xLxK)(NS)-CZ thick films along the (001) direction, and the textured thick film (x = 0.0375) had a large Lotgering factor of 95.6%. The PC-T-O multi-structure was observed in this thick film (x = 0.0375), but the thick film (x = 0.0325) showed a PC-O structure owing to the diffusion of the NN templates into the thick film. The textured thick film (x = 0.0375) exhibited an increased d33 of 625 pC/N because of the PC-T-O multi-structure and the lineup of grains along the [001] direction. A textured thick film (x = 0.0375) was used to fabricate a planar-type actuator to confirm its applicability to electrical devices. This actuator exhibits large acceleration (580.3 G) and displacement (150 μm) at a low electric field of 0.2 kV/mm with a short response time of 3.0 ms. Therefore, the (N0.5-xLxK)(NS)-CZ thick films are excellent lead-free piezoceramics. 相似文献
50.
Sang-Ik Han Jong-Hyun Chae Kristin Bilyeu J. Grover Shannon Jeong-Dong Lee 《Journal of the American Oil Chemists' Society》2014,91(2):229-234
Soybean [Glycine max (L.) Merr] with increased oleic acid is desirable to improve oxidative stability and functionality of soybean seed oil. Recently, soybean genotypes with high oleic acid (≥70 %) were developed by breeding programs. Efficient and effective identification of high oleic acid soybean genotypes using non-destructive near infrared reflectance (NIR) on whole seeds would greatly enhance progress in breeding programs. The objective of this study was to develop a calibration equation for NIR determination of high oleic acid from single soybean seeds. A total of 600 intact, single F2 seeds were scanned by NIR. Spectral data were collected between 400 and 2,500 nm at 2 nm intervals. The relationship between NIR spectral patterns of each soybean seed and its oleic acid content was examined. The best predicted equations for oleic acid were selected on the basis of minimizing the standard error of cross-validation and increasing the coefficient of determination. Validation demonstrated that the equations for determining total oleic acid and over 50 % oleic acid content had high predictive ability (r 2 = 0.91 and r 2 = 0.99, respectively). To validate the newly developed equation, F2 seeds from a different genetic background were tested. Again, high oleic acid from single soybean seeds was accurately predicted from various genetic backgrounds. Therefore, applying the calibration equations to NIR will be useful to rapidly and efficiently select high oleic acid soybean genotypes in breeding programs. 相似文献