A solid sustained-release energetic material sample,an eruption device and a complete test system were prepared further to analyse the combustion characteristics of solid sustainedrelease energetic materials.The high-...A solid sustained-release energetic material sample,an eruption device and a complete test system were prepared further to analyse the combustion characteristics of solid sustainedrelease energetic materials.The high-temperature heat flux generated by the combustion of the samples from the eruption device was used to penetrate the Q235 target plate.In addition,the meaning and calculation formula of energy density characterising the all-around performance of heat flux were proposed.The numerical simulation of the combustion effect of samples was carried out.According to the data comparison,the numerical simulation results agreed with the experimental results,and the maximum deviation between the two was less than 8.9%.In addition,the structure of the combustion wave and high-temperature jet was proposed and analysed.Based on theoretical analysis,experimental research and numerical simulation,the theoretical burning rate formula of the sample was established.The maximum error between the theoretically calculated mass burning rate and the experimental results was less than 9.8%.Therefore,using the gas-phase steady-state combustion model to study the combustion characteristics of solid sustained-release energetic materials was reasonable.The theoretical burning rate formula also had high accuracy.Therefore,the model could provide scientific and academic guidance for the theoretical research,system design and practical application of solid sustained-release energetic materials in related fields.展开更多
Due to the advantages of low energy consumption and high CO_(2) selectivity, the development of solid amine-based materials has been regarded as a hot research topic in the field of DAC for the past decades.The adsorp...Due to the advantages of low energy consumption and high CO_(2) selectivity, the development of solid amine-based materials has been regarded as a hot research topic in the field of DAC for the past decades.The adsorption capacity and stability over multiple cycles have been the top priorities for evaluation of practical application value. Herein, we synthesized a novel DAC material by loading TEPA onto defect-rich Mg_(0.55)Al-O MMOs with enhanced charge transfer effect. The optimal Mg_(0.55)Al-O-TEPA67% demonstrates the highest CO_(2)uptake of(3.0 mmol g^(-1)) and excellent regenerability, maintaining ~90% of the initial adsorption amount after 80 adsorption/desorption cycles. The in situ DRIFTS experiments suggested the formation of bicarbonate species under wet conditions. DFT calculations indicated that the stronger bonding between Mg_(0.55)Al-O support and solid amine was caused by the abundance of oxygen defects on MMOs confirmed by XPS and ESR, which favors the charge transfer between the support and amine,resulting in intense interaction and excellent regenerability. This work for the first time conducted comprehensive and systematic investigation on the stabilization mechanism for MMOs supported solid amine adsorbents with highest uptake and superior cyclic stability in depth, which is different from the most popular SiO_(2)-support, thus providing facile strategy and comprehensive theoretical mechanism support for future research about DAC materials.展开更多
A topology optimization method based on the solid isotropic material with penalization interpolation scheme is utilized for designing gradient coils for use in magnetic resonance microscopy.Unlike the popular stream f...A topology optimization method based on the solid isotropic material with penalization interpolation scheme is utilized for designing gradient coils for use in magnetic resonance microscopy.Unlike the popular stream function method,the proposed method has design variables that are the distribution of conductive material.A voltage-driven transverse gradient coil is proposed to be used as micro-scale magnetic resonance imaging(MRI)gradient coils,thus avoiding introducing a coil-winding pattern and simplifying the coil configuration.The proposed method avoids post-processing errors that occur when the continuous current density is approximated by discrete wires in the stream function approach.The feasibility and accuracy of the method are verified through designing the z-gradient and y-gradient coils on a cylindrical surface.Numerical design results show that the proposed method can provide a new coil layout in a compact design space.展开更多
文摘A solid sustained-release energetic material sample,an eruption device and a complete test system were prepared further to analyse the combustion characteristics of solid sustainedrelease energetic materials.The high-temperature heat flux generated by the combustion of the samples from the eruption device was used to penetrate the Q235 target plate.In addition,the meaning and calculation formula of energy density characterising the all-around performance of heat flux were proposed.The numerical simulation of the combustion effect of samples was carried out.According to the data comparison,the numerical simulation results agreed with the experimental results,and the maximum deviation between the two was less than 8.9%.In addition,the structure of the combustion wave and high-temperature jet was proposed and analysed.Based on theoretical analysis,experimental research and numerical simulation,the theoretical burning rate formula of the sample was established.The maximum error between the theoretically calculated mass burning rate and the experimental results was less than 9.8%.Therefore,using the gas-phase steady-state combustion model to study the combustion characteristics of solid sustained-release energetic materials was reasonable.The theoretical burning rate formula also had high accuracy.Therefore,the model could provide scientific and academic guidance for the theoretical research,system design and practical application of solid sustained-release energetic materials in related fields.
基金supported by the Fundamental Research Funds for the Central Universities (2019JQ03015)the National Natural Science Foundation of China (42075169, U1810209)the Beijing Municipal Education Commission through the Innovative Transdisciplinary Program “Ecological Restoration Engineering”。
文摘Due to the advantages of low energy consumption and high CO_(2) selectivity, the development of solid amine-based materials has been regarded as a hot research topic in the field of DAC for the past decades.The adsorption capacity and stability over multiple cycles have been the top priorities for evaluation of practical application value. Herein, we synthesized a novel DAC material by loading TEPA onto defect-rich Mg_(0.55)Al-O MMOs with enhanced charge transfer effect. The optimal Mg_(0.55)Al-O-TEPA67% demonstrates the highest CO_(2)uptake of(3.0 mmol g^(-1)) and excellent regenerability, maintaining ~90% of the initial adsorption amount after 80 adsorption/desorption cycles. The in situ DRIFTS experiments suggested the formation of bicarbonate species under wet conditions. DFT calculations indicated that the stronger bonding between Mg_(0.55)Al-O support and solid amine was caused by the abundance of oxygen defects on MMOs confirmed by XPS and ESR, which favors the charge transfer between the support and amine,resulting in intense interaction and excellent regenerability. This work for the first time conducted comprehensive and systematic investigation on the stabilization mechanism for MMOs supported solid amine adsorbents with highest uptake and superior cyclic stability in depth, which is different from the most popular SiO_(2)-support, thus providing facile strategy and comprehensive theoretical mechanism support for future research about DAC materials.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51675506 and 51275504)the German Research Foundation(DFG)(Grant Nos.#ZA 422/5-1 and#ZA 422/6-1)
文摘A topology optimization method based on the solid isotropic material with penalization interpolation scheme is utilized for designing gradient coils for use in magnetic resonance microscopy.Unlike the popular stream function method,the proposed method has design variables that are the distribution of conductive material.A voltage-driven transverse gradient coil is proposed to be used as micro-scale magnetic resonance imaging(MRI)gradient coils,thus avoiding introducing a coil-winding pattern and simplifying the coil configuration.The proposed method avoids post-processing errors that occur when the continuous current density is approximated by discrete wires in the stream function approach.The feasibility and accuracy of the method are verified through designing the z-gradient and y-gradient coils on a cylindrical surface.Numerical design results show that the proposed method can provide a new coil layout in a compact design space.
