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91.
Moritz Riebisch Philipp Weiß Clemens Cremer Ibrahim Aboulkhair Andreas Bührig-Polaczek 《Materials Science & Technology》2018,34(6):725-730
Solid solution-strengthened ductile iron (DI) exhibits outstanding mechanical properties due to the high silicon content. The strengthening by silicon addition is limited since additions above 4.3?wt-% lead to embrittlement. For a further improvement of mechanical properties, other alloying elements need to be considered. In the present work, the effect of various copper additions on the microstructure and the mechanical properties of solid solution-strengthened DI were investigated. The results show that no appreciable strengthening can be achieved by copper addition without the formation of pearlite in the matrix. The pearlite content increases considerably for Cu-additions above 0.23?wt-% and is independent of the cooling rate for the cooling conditions analysed. 相似文献
92.
Nasser A.M. Barakat A.H. Zaki Enas Ahmed A.A. Farghali Fahad S. Al-Mubaddel 《International Journal of Hydrogen Energy》2018,43(16):7990-7997
Theoretically, tri-ammonium phosphate (NH4)3PO4 embeds considerable amount of hydrogen. Typically, the expected hydrogen release from this cheap and stable material is 73.83 mmol/gsalt if a proper catalyst is exploited in the hydrolysis reaction. In this study FexCo1?x-doped titanium oxide nanotubes are introduced as an efficient photocatalyst under solar radiation. The introduced modified titanium oxide nanotubes have been prepared in two successive steps. First, Na-doped TiO2 nanotubes were synthesized by hydrothermal treatment in presence of 10 N NaOH solution at 160 °C for 16 h. Then, doping by the proposed metals was carried out by ion exchange process in a microwave oven. X-ray photoelectron microscopy (XPS) and transmission electron microscopy (TEM) confirmed the success of the doping process and the nanotubular morphology, respectively. Study the photo characteristics indicated that the proposed metal doping shifted the band gap from UV to the visible light region as the estimated band gap energies for the as-prepared and doped nanotubes were 3.4 and 2.1 eV, respectively. Moreover, distinct enhancement for the visible light absorption capacity was observed. Accordingly, a distinguished improvement in the photocatalytic activity toward tri-ammonium phosphate hydrolysis was observed. However, the two metals content has a strong influence on the amount of the obtained hydrogen per gram of tri-ammonium phosphate salt. Numerically, the maximum obtained hydrogen was 4.0, 11.2, 11.2, 11.6, 13.4, 16.5, 17.4, 13.4 and 9.8 mmol/gsalt for the pristine TiO2, and FexCo1?x-doped TiO2 with x = 1, 0.8, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.0, respectively. 相似文献
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96.
Dejun Xu Jiali Wan Dehua Xu Tao Luo Yanjun Zhong Xiushan Yang Lin Yang Zhiye Zhang Xinlong Wang 《加拿大化工杂志》2020,98(3):665-675
A new process is proposed in which citric acid is added during the ammoniation process of wet-process phosphoric acid (WPA) to chelate metal ions to produce fertilizer ammonium dihydrogen phosphate (MAP) containing medium trace elements. The parameters of the chelation reaction were studied systematically and the results show that the optimal reaction condition is pH 3.0, reaction time 60 minutes, temperature 50.0°C, and citric acid content 1.48%. The XRD patterns show that the water-insoluble compounds are complex mixtures, and the composition of the water-insoluble compounds are changed through the addition of citric acid. FTIR and XPS analyes further demonstrate that water-insoluble compounds are complex mixtures. The XRD patterns of the MAP products indicate that the structure and morphology of the MAP were changed by the addition of citric acid. In addition, the contents of major elements, medium elements, and trace elements in the MAP product are 68.72%, 0.24%, and 0.50%, respectively, which is consistent with the relevant China national standard. 相似文献
97.
Chu Shi Dr. Yan Li Prof. Ning Gu 《Chembiochem : a European journal of chemical biology》2020,21(19):2722-2732
Iron-based nanozymes are currently one of the few clinical inorganic nanoparticles for disease diagnosis and treatment. Overcoming the shortcomings of natural enzymes, such as easy inactivation and low yield, combined with their special nanometer properties and magnetic functions, iron-based nanozymes have broad prospects in biomedicine. This minireview summarizes their preparation, biological activity, catalytic mechanism, and applications in diagnosis and treatment of diseases. Finally, challenges to their future development and the trends of iron-based nanozymes are discussed. The purpose of this minireview is to better understand and reasonably speculate on the rational design of iron-based nanozymes as an increasingly important new paradigm for diagnostics. 相似文献
98.
A series of polyethylene glycol-linked Gemini fatty alcohol phosphate surfactants (GFAP) were prepared with long chain n-alkanol (C = 8, 12, 16, 18), polyethylene glycol (PEG-200, PEG-400, PEG-600, PEG-800, PEG-1000) and phosphorus oxychloride (POCl3). The structure of the prepared surfactants was characterized by Fourier transform infrared spectrometer (FT-IR). The surfactants were employed for the modification of chrome-tanned leather. The morphological changes of chrome-tanned leather and modified chrome-tanned leather were observed by scanning electron microscopy (SEM). The relationship between the alkyl chain length and molecular weight of the PEG and the hydrophobicity, softness, mechanical strength of modified chrome-tanned leather was also discussed. The experimental results showed that the mechanical strength and softness of modified chrome-tanned leather were enhanced with an increase of alkyl chain length, while the hydrophobicity, mechanical strength and softness were decreased with an increase of molecular weight of the PEG. The hydrophobicity, mechanical strength and softness of modified chrome-tanned leather were optimized for an alkyl chain length of 16. Therefore, 16–200 Gemini phosphate surfactants with an alkyl chain length of 16 and a PEG molecular weight of 200 have a good comprehensive modification effect on Chrome-tanned leather, the tensile strength, tear strength and softness of modified chrome-tanned leather are 57.07 N mm−2, 79.49 N mm−1, 9.73 mm, respectively. 相似文献
99.
铁矿是一种重要的矿物资源,其价格主要由市场决定。因此,在价格一定的条件下,铁矿企业要想进一步提高经济效益,提高市场竞争力,主要通过降低成本的途径来实现。以白象山铁矿为例,为实现白象山铁矿原矿成本控制,主要从技术创新和生产管理出发,通过采用防治水技术优化、采用安全高效采矿工艺、分级支护、大数据精准充填、自动化技术攻关、生产管理降本、财务收支管理降本、技术管理降本、增加零星工程自营等多种方法来降低成本。精细化成本管控体系不仅为该矿创造了巨大的经济效益,而且可为其他类似条件的矿山提供借鉴。 相似文献
100.
《Ceramics International》2020,46(10):15935-15942
In the present study, the effect of silica nanoparticles on the formation of nano-mullite phase for use in the manufacture of silicon carbide based ceramic foam filters has been investigated. Polyurethane foam filters were impregnated with nanosilica particles by slip casting. In this method, the effect of different percentages of nanosilica particles in the slurry on compressive strength, density and porosity of ceramic foam filters was investigated. The effect of silica nanoparticles on viscosity of slurry was studied using rheometric test. So, sample S15 was selected to proceed. For thermal treatment of ceramic foams, different sintering temperatures were investigated and the best temperature was reported at 1250 °C. Compressive strength results showed that with increasing nano-silica content, CCS increased. XRD results from the samples showed that the nano-mullite phase was formed at 1250 °C along with silicon carbide and alumina phases. Scanning electron microscope images (SEM) showed that the mullite phase was formed in nano-dimensions in ceramic foam bodies. The formation of mullite phase in the microstructure of the filters is one of the factors of strengthening and increased refractory characteristics. EDS analysis by the scanning electron microscopy of the filter which passed ductile iron melt showed that cast iron inclusions and impurities were mostly consisted from FeO, MnO, SiO2, Al2O3, MgO and CO, which were trapped inside the ceramic filter. 相似文献