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21.
Inkjet-printed electronics are showing promising potential in practical applications, but methods for real-time, non-contact monitoring of printing quality are lacking. This work explores Terahertz (THz) sensing as an approach for such monitoring. It is demonstrated that alterations in the localised dielectric characteristics of inkjet-printed electronics can be qualitatively distinguished using quasi-optically-based, sub-THz reflection spectroscopy. Decreased reflection coefficients caused by the sintering process are observed and quantified. Using THz near-field scanning imaging, it is shown that sintering produces a more uniform spatial distribution of permittivity in the printed carbon patterns. Images generated using THz-TDS based imaging are presented, demonstrating the combination of high resolution imaging with quantification of complex permittivities. This work, for the first time, demonstrates the feasibility of quality control in printed electronic-ink with THz sensing, and is of practical significance to the development of in-situ and non-contact commercial-quality characterisation methods for inkjet-printed electronics. 相似文献
22.
《Ceramics International》2017,43(15):12070-12078
It is well documented that biological hydroxyapatite (HA) differs from pure and synthetically produced HA, and contains of a mixture of calcium phosphate (CaP) phases in addition to a range of impurity ions, such as strontium (Sr2+), zinc (Zn2+), magnesium (Mg2+), fluoride (F-) and carbonate(CO32-), but to name a few. Further to this, biological apatite is generally in the form of rod (or needle-like) crystals in the nanometre (nm) size range, typically 60 nm in length by 5–20 nm wide. In this study, a range of nano-hydroxyapatite (nHA), substituted nHA materials and co-substituted nHA (based on Sr2+ and Zn2+) were manufactured using an aqueous precipitation method. Sr2+ and Zn2+ were chosen due to the significant performance enhancements that these substitutions can deliver. The materials were then characterised using Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM) techniques. The TEM results show that all of the samples produced were nano-sized, with Zn-substituted nHA being the smallest crystals around 27 nm long and 8 nm wide. The FTIR, XRD and XPS results all confirm that the materials had undergone substitution with either Sr2+ and Zn2+, for Ca2+ within the HA lattice (or both in the case of the co-substituted materials). The FTIR results confirmed that all of the samples were carbonated, with a significant loss of hydroxylation as a consequence of the incorporation of Sr2+ and Zn2+ into the HA lattice. None of the materials synthesised here in this study contained any other impurity CaP phases. Therefore this study has shown that substituted and co-substituted nanoscale apatites can be prepared, and that the degree of substitution (and the substituting ion) can have a profound effect of the attendant materials’ properties. 相似文献
23.
《Ceramics International》2016,42(7):8460-8466
Dense bulk alumina (Al2O3) has been prepared by explosive compaction and its microstructure has been investigated by optical microscopy, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The average microhardness of the alumina compact is about 171 HV0.025. Ultra-thin alumina films with glassy (translucent) appearance formed during the explosive compaction process. Nanograin Al2O3 particles are covered by amorphous Al2O3 which help to achieve a dense microstructure by promoting interparticles bonding. Phase transformation from γ-Al2O3 to α-Al2O3 during the explosive compaction process has been confirmed. Formation of the alumina compact is due to the large cooling rate and the high pressure during the explosive compaction. 相似文献
24.
《Measurement》2016
It is proposed a device for the study of the real-time aggregation of white thrombi in whole blood. This device allows extrapolating the 3D-shape of platelets clotting within artificial capillaries, by simultaneously monitoring the electrical impedance between a pair of specifically designed gold electrodes and 2D optical image of pixel luminance of the fluorescent labeled platelets. Up to 30 3D images per minute have been obtained, for a process which requires few minutes before the aggregation of large thrombi structures, a noticeable result with respect to other 3D-shape reconstruction methods. The contribution of this paper mainly consists in the study of an uncertainty model which, in our opinion, is of fundamental importance to provide a valuable metrological estimation of thrombus growth under flow conditions. 相似文献
25.
《Ceramics International》2016,42(3):4185-4193
Single crystal of new cadmium and neodymium molybdate solid solution (Cd0.958Nd0.028□0.014MoO4, where □ denotes cationic vacancies) has been successfully grown by the Czochralski method. The X-ray diffraction analysis confirmed that this solid solution crystallizes in the scheelite type structure, the Nd3+ ions do not show long-range order and they are randomly distributed in the unit cell, substituting the Cd2+ ions. As a consequence, the unexpected properties of CdMoO4:Nd3+ are observed such as the energy gap (~1.77 eV) twice smaller than that of the matrix CdMoO4, a paramagnetic state with the short-range ferromagnetic interactions, behavior related to the electrical conductor with p–n transition along the 〈100〉 axis, the semiconducting behavior with n–p transition along the 〈001〉 axis and the diode-like behavior found to be of Schottky- or Maxwell-Wagner type. Therefore, we predict great potential of this single crystal for technical applications in electronic devices. 相似文献
26.
Hilmi YurdakulServet Turan 《Ceramics International》2011,37(5):1501-1505
Outstanding properties for SiAlON ceramics can be obtained by tailoring the microstructure through α-SiAlON and β-SiAlON phase content as well as a type of secondary phases. It is so far well known that while some of the elements could be accommodated in α-SiAlON structure, β-SiAlON does not easily accommodate different elements in its structure. In this work, SiAlON ceramics were produced by using β-Si3N4 starting powder containing small amount of iron and chromium and the possible incorporation of iron and chromium into β-SiAlON structure was investigated by using analytical transmission electron microscopy (TEM) techniques. As a result of analytical TEM analysis, it is found that transition metals (Cr and Fe) can enter into the β-SiAlON crystal structure. 相似文献
27.
Joel MolinaAlfonso Torres Mauro LandaPablo Alarcon Manuel Escobar 《Materials Science and Engineering: B》2011,176(17):1353-1358
In this work, the physical, chemical and electrical properties of Metal-Oxide-Semiconductor (MOS) capacitors with Spin-On-Glass (SOG)-based thin films as gate dielectric have been investigated. Experiments of SOG diluted with two different solvents (2-propanol and deionized water) were done in order to reduce the viscosity of the SOG solution so that thinner films (down to ∼20 nm) could be obtained and their general characteristics compared. Thin films of SOG were deposited on silicon by the sol-gel technique and they were thermally annealed using conventional oxidation furnace and Rapid Thermal Processing (RTP) systems within N2 ambient after deposition. SOG dilution using non-organic solvents like deionized water and further annealing (at relatively high temperatures ≥450 °C) are important processes intended to reduce the organic content of the films. Fourier-Transform Infrared (FTIR) Spectroscopy results have shown that water-diluted SOG films have a significant reduction in their organic content after increasing annealing temperature and/or dilution percentage when compared to those of undiluted SOG films. Both current-voltage (I-V) and capacitance-voltage (C-V) measurements show better electrical characteristics for SOG-films diluted in deionized water compared to those diluted in 2-propanol (which is an organic solvent). The electrical characteristics of H2O-diluted SOG thin films are very similar to those obtained from high quality thermal oxides so that their application as gate dielectrics in MOS devices is promising. Finally, it has been demonstrated that by reducing the organic content of SOG-based thin films, it is possible to obtain MOS devices with better electrical properties. 相似文献
28.
Synthesis and luminescence properties of Eu3+ and Tm3+-doped ZnNb2O6 nanocrystals by the sol–gel process were investigated. The products were characterized by differential thermal analysis (DTA), scanning electron microscopy (SEM), and photoluminescence spectroscopy (PL). ZnNb2O6:Eu3+ shows bright red luminescence with maximum peak at 613 nm attributed to 5D0 → 7F2 transition. The major blue emission peak of ZnNb2O6:Tm3+ was at 483 nm, corresponding to the transitions 1G4 → 3H6. The optimum concentration of Eu3+ and Tm3+ showing the maximum PL intensity was 4 mol% and 1 mol%, respectively. 相似文献
29.
We compared novel size‐selective separators, namely the textile fabrics of polyphenylene sulfide (PPS) and sulfonated polyphenylene sulfide (S‐PPS), and the nonwoven fabrics of polypropylene80 (PP 80) and PP 100, with commonly used ion exchange separators (Nafion 117 and cation exchange membane‐7000; CMI‐7000) in terms of power generation, oxygen diffusion, and biofilm formation in a single chamber microbial fuel cell. Size‐selective separators exhibited more power generation than ion selective separators. MFC operation with size‐selective separators generated power output ranging 0.407 to 0.591 V (1000 Ω), whereas with Nafion it was 0.272 V. In polarization analysis, S‐PPS resulted in the highest power density of 190 mW/m2, whereas it was 24 mW/m2 with Nafion‐117. Size selective separators showed similar or higher proton conductivity than Nafion 117. Oxygen mass transfer coefficients of size‐selective separators (KO = 3.7 ∼ 7.5 × 10−5) were lower or similar to Nafion (KO = 7.5 × 10−5). Fourier‐transform infrared spectroscopy and scanning electron microscopy analysis revealed that all separators (PP80, S‐PPS, and Nafion) contained proteins or carbon chain compounds after 300‐day operation, and however, Nafion 117 seems to be more susceptible to biofouling than the other separators. 相似文献
30.
《Ceramics International》2017,43(9):7282-7289
This study aims to investigate the hydrothermally synthesized cobalt(II) hydroxide-based materials, which will be thermally converted to generate Co3O4 nanostructures; an important class of materials characterized by good electrochemical, catalytic and optical properties. First, cobalt(II) hydroxide nanostructures were prepared via hydrothermal hydrolysis of two different precursors (cobalt(II) chloride salt and dichlorobis(thiourea)cobalt(II) complex) exposure to an ammonia atmosphere, and then the obtained α-Co(OH)2 and α-Co2(OH)3Cl nanostructures were calcined to produce Co3O4 nanostructures that were characterized by FT-IR, XRD, UV–vis DRS and SEM techniques. The effects of the nature of the precursor, its concentration, and of the temperature and reaction time on size and morphology of the product were also investigated. 相似文献