A new method for separating and recovering tin from a low-grade tin middling with high Si content and low Fe content by roasting with anthracite coal was researched by studying the reaction mechanism and performing an...A new method for separating and recovering tin from a low-grade tin middling with high Si content and low Fe content by roasting with anthracite coal was researched by studying the reaction mechanism and performing an industrial test,in which the Sn was sulfurized into SnS(g)and then collected using a dust collector.The Fe–Sn alloy may be formed at roasting temperatures above 950°C,and like the roasting temperature increases,the Sn content and Sn activity in this Fe–Sn alloy decrease.Also,more FeS can be formed at higher temperatures and then the formation of FeO–FeS with a low melting point is promoted,which results in more serious sintering of this low-grade tin middling.And from the thermodynamics and kinetics points of view,the volatilization of the Sn decreases at extremely high roasting temperatures.The results of the industrial test carried out in a coal-fired rotary kiln show that the Sn volatilization rate reaches 89.7%and the Sn is concentrated in the collected dust at a high level,indicating that the Sn can be effectively extracted and recovered from the low-grade tin middling with a high Si content and low Fe content through a reduction–sulfurization roasting process.展开更多
In this study,based on a closed bomb test combined with computational fluid dynamics,a structural finite element method,and an acoustic boundary element method,a fluid-solid acoustic one-way coupling calculation model...In this study,based on a closed bomb test combined with computational fluid dynamics,a structural finite element method,and an acoustic boundary element method,a fluid-solid acoustic one-way coupling calculation model is established for the combustion process of energetic materials in a closed bomb,and the effectiveness of the model is verified by experiments.It is found that the maximum peak sound pressure increases exponentially with an increase in loading doses or gas pressure.However,a change in the combustion coefficient of the energetic materials has little effect on the noise generated during the combustion process in the closed bomb.When the combustion coefficient is reduced by a multiple of 16,the maximum transient sound pressure is reduced by 1.79 dB,and the sound pressure level in the frequency band is reduced by 1.75 dB.With an increase in shell thickness,the combustion noise of the energetic materials in the closed bomb decreases,and the reduction range of the combustion noise increases with the increase in shell thickness.展开更多
Hill-like polycrystalline diamond grains(HPDGs)randomly emerged on a heavy boron-doped p+single-crystal diamond(SCD)film by prolonging the growth duration of the chemical vapor deposition process.The Raman spectral re...Hill-like polycrystalline diamond grains(HPDGs)randomly emerged on a heavy boron-doped p+single-crystal diamond(SCD)film by prolonging the growth duration of the chemical vapor deposition process.The Raman spectral results confirm that a relatively higher boron concentration(~1.1×10^(21) cm^(-3))is detected on the HPDG with respect to the SCD region(~5.4×10^(20) cm^(-3)).It demonstrates that the Au/SCD interface can be modulated from ohmic to Schottky contact by varying the surface from hydrogen to oxygen termination.The current-voltage curve between two HPDGs is nearly linear with either oxygen or hydrogen termination,which means that the HPDGs provide a leakage path to form an ohmic contact.There are obvious rectification characteristics between oxygen-terminated HPDGs and SCD based on the difference in boron doping levels in those regions.The results reveal that the highly boron-doped HPDGs grown in SCD can be adopted as ohmic electrodes for Hall measurement and electronic devices.展开更多
Surface terminations of diamond play an important role in determining the electric properties of diamond-based electronic devices.We report an ultraviolet/ozone(UV/ozone)treatment process on hydrogen-terminated single...Surface terminations of diamond play an important role in determining the electric properties of diamond-based electronic devices.We report an ultraviolet/ozone(UV/ozone)treatment process on hydrogen-terminated single crystal diamond(H-diamond)to modulate the carrier behavior related to varying oxygen adsorption on surfaces.By UV/ozone treatments,the induced oxygen radicals are chemically adsorbed on the H-terminated diamond and replace the original adsorbed H,which is analyzed by x-ray photoelectron spectroscopy.The concentration of oxygen adsorbed on surface increases from^3%to^8%with increasing the ozone treatment time from 20 s to 600 s.It is further confirmed by examining the wettability properties of the varying diamond surfaces,where the hydrophobic for H-termination transfers to hydrophilic for partly O-termination.Hall effect measurements show that the resistance(hole mobility)of the UV/ozone-treated H-diamond continuously increases(decrease)by two orders of magnitude with increasing UV/ozone treatment time from 20 s to 600 s.The results reveal that UV/ozone treatment becomes an efficient method to modulate the surface electrical properties of H-diamonds for further investigating the oxygenation effect on two-dimensional hole gas based diamond devices applied in some extreme environments.展开更多
Aiming at the problems of low accuracy and poor robustness that existed in the current hot rolling strip width spread model,an improved strip spread prediction model based on a material forming mechanism and Bayesian ...Aiming at the problems of low accuracy and poor robustness that existed in the current hot rolling strip width spread model,an improved strip spread prediction model based on a material forming mechanism and Bayesian optimized adaptive differential evolution algorithm(BADE)was proposed.At first,we improved the original spread mechanism model by adding the weight and bias term to enhance the model robustness based on rolling temperature.Then,the BADE algorithm was proposed to optimize the improved spread mechanism model.The optimization algorithm is based on a novel adaptive differential evolution algorithm,which can effectively achieve the global optimal solution.Finally,the prediction performances of five machine learning algorithms were compared in experiments.The results show that the prediction accuracy of the improved spread model is obviously better than that of the machine learning algorithms,which proves the effectiveness of the proposed method.展开更多
基金This work was financially supported by the National Science Fund for General Projects of China(No.51874153).
文摘A new method for separating and recovering tin from a low-grade tin middling with high Si content and low Fe content by roasting with anthracite coal was researched by studying the reaction mechanism and performing an industrial test,in which the Sn was sulfurized into SnS(g)and then collected using a dust collector.The Fe–Sn alloy may be formed at roasting temperatures above 950°C,and like the roasting temperature increases,the Sn content and Sn activity in this Fe–Sn alloy decrease.Also,more FeS can be formed at higher temperatures and then the formation of FeO–FeS with a low melting point is promoted,which results in more serious sintering of this low-grade tin middling.And from the thermodynamics and kinetics points of view,the volatilization of the Sn decreases at extremely high roasting temperatures.The results of the industrial test carried out in a coal-fired rotary kiln show that the Sn volatilization rate reaches 89.7%and the Sn is concentrated in the collected dust at a high level,indicating that the Sn can be effectively extracted and recovered from the low-grade tin middling with a high Si content and low Fe content through a reduction–sulfurization roasting process.
文摘In this study,based on a closed bomb test combined with computational fluid dynamics,a structural finite element method,and an acoustic boundary element method,a fluid-solid acoustic one-way coupling calculation model is established for the combustion process of energetic materials in a closed bomb,and the effectiveness of the model is verified by experiments.It is found that the maximum peak sound pressure increases exponentially with an increase in loading doses or gas pressure.However,a change in the combustion coefficient of the energetic materials has little effect on the noise generated during the combustion process in the closed bomb.When the combustion coefficient is reduced by a multiple of 16,the maximum transient sound pressure is reduced by 1.79 dB,and the sound pressure level in the frequency band is reduced by 1.75 dB.With an increase in shell thickness,the combustion noise of the energetic materials in the closed bomb decreases,and the reduction range of the combustion noise increases with the increase in shell thickness.
基金Project supported by the Key-Area Research and Development Program of Guangdong Province(Grant No.2020B0101690001)the National Natural Science Foundation of China(NSFC)(Grant No.51972135).
文摘Hill-like polycrystalline diamond grains(HPDGs)randomly emerged on a heavy boron-doped p+single-crystal diamond(SCD)film by prolonging the growth duration of the chemical vapor deposition process.The Raman spectral results confirm that a relatively higher boron concentration(~1.1×10^(21) cm^(-3))is detected on the HPDG with respect to the SCD region(~5.4×10^(20) cm^(-3)).It demonstrates that the Au/SCD interface can be modulated from ohmic to Schottky contact by varying the surface from hydrogen to oxygen termination.The current-voltage curve between two HPDGs is nearly linear with either oxygen or hydrogen termination,which means that the HPDGs provide a leakage path to form an ohmic contact.There are obvious rectification characteristics between oxygen-terminated HPDGs and SCD based on the difference in boron doping levels in those regions.The results reveal that the highly boron-doped HPDGs grown in SCD can be adopted as ohmic electrodes for Hall measurement and electronic devices.
基金Supported by the National Natural Science Foundation of China under Grant Nos.51672102 and 51972135。
文摘Surface terminations of diamond play an important role in determining the electric properties of diamond-based electronic devices.We report an ultraviolet/ozone(UV/ozone)treatment process on hydrogen-terminated single crystal diamond(H-diamond)to modulate the carrier behavior related to varying oxygen adsorption on surfaces.By UV/ozone treatments,the induced oxygen radicals are chemically adsorbed on the H-terminated diamond and replace the original adsorbed H,which is analyzed by x-ray photoelectron spectroscopy.The concentration of oxygen adsorbed on surface increases from^3%to^8%with increasing the ozone treatment time from 20 s to 600 s.It is further confirmed by examining the wettability properties of the varying diamond surfaces,where the hydrophobic for H-termination transfers to hydrophilic for partly O-termination.Hall effect measurements show that the resistance(hole mobility)of the UV/ozone-treated H-diamond continuously increases(decrease)by two orders of magnitude with increasing UV/ozone treatment time from 20 s to 600 s.The results reveal that UV/ozone treatment becomes an efficient method to modulate the surface electrical properties of H-diamonds for further investigating the oxygenation effect on two-dimensional hole gas based diamond devices applied in some extreme environments.
基金support from National Natural Science Foundation of China(Grant Nos.61633019,61533013 and 62273234).
文摘Aiming at the problems of low accuracy and poor robustness that existed in the current hot rolling strip width spread model,an improved strip spread prediction model based on a material forming mechanism and Bayesian optimized adaptive differential evolution algorithm(BADE)was proposed.At first,we improved the original spread mechanism model by adding the weight and bias term to enhance the model robustness based on rolling temperature.Then,the BADE algorithm was proposed to optimize the improved spread mechanism model.The optimization algorithm is based on a novel adaptive differential evolution algorithm,which can effectively achieve the global optimal solution.Finally,the prediction performances of five machine learning algorithms were compared in experiments.The results show that the prediction accuracy of the improved spread model is obviously better than that of the machine learning algorithms,which proves the effectiveness of the proposed method.
