P507 solvent extraction is the main method to separate and purify the rare earth products.The emulsification may be caused by the impurities in process of extracting rare earths,and these result in huge economic loss ...P507 solvent extraction is the main method to separate and purify the rare earth products.The emulsification may be caused by the impurities in process of extracting rare earths,and these result in huge economic loss and decrease the quality of rare earth products.In recent researches,the extractant was prone to emulsification,and aluminum content of rare earth products also increased,while aluminum concentration of feed was higher.Pointing to this problem,the structural change of saponification P507 extracting aluminum and lanthanum was investigated by infrared spectroscopy,and the results showed that Al ions exchanged with H of P-O-H to become P-O-Al.Because aluminum held the characteristic of hydrophilic after extracted in the form of hydroxyl polymer ions and this provided conditions for the formation of micro emulsion.The organic phase and aqueous phase were investigated by polarizing microscope after aluminum was extracted.The results showed that the organic phase was clear when the extraction capacity of Al was less than 5 g/L.If the extraction capacity of Al exceeded 5 g/L,it formed W/O of ME(micro emulsion),leading to form emulsion of the organic phase.When Al concentration of feed was less than 1 g/L,the aqueous phase would form O/W of ME.If aluminum was extracted by saponification P507 firstly,then the the organic phase loading aluminum extracted rare earth continually,the organic and aqueous phase formed emulsification easily.展开更多
Using acridine dyes as sensitizers,the photoisomerization of three norbornadiene derivatives was investigated.The valence isomerization of nor- bornadiene derivatives(Ⅰ_a,Ⅰ_b,Ⅰ_c)gave their corresponding isomers of...Using acridine dyes as sensitizers,the photoisomerization of three norbornadiene derivatives was investigated.The valence isomerization of nor- bornadiene derivatives(Ⅰ_a,Ⅰ_b,Ⅰ_c)gave their corresponding isomers of quadri- cyclane(Ⅱ_a,Ⅱ_b,Ⅱ_c)operating with relatively high efficiency in an electron transfer mode.Their quantum yields of isomerization were determined and the reaction mechanism was discussed.展开更多
In recent years,with the continuous progress of science and technology,the development of information technology has also begun to change.The popularity of the application of modern information technology in the field...In recent years,with the continuous progress of science and technology,the development of information technology has also begun to change.The popularity of the application of modern information technology in the field of education is very high.College students can obtain the knowledge and content they need from the network.Teachers are no longer the only source of information for students,which promotes the improvement of students academic performance and cultivates students autonomous learning ability.As a university teacher,the author discusses how to motivate college students autonomous learning in the process of virtual project-based practical teaching,hoping that this paper can provide a certain direction for the future development of university education and guide college students to cultivate their autonomous learning ability.展开更多
Sodium-ion batteries(SIBs)have attracted great interest for use as the next generation rechargeable batteries due to the abundant sodium natural resources and similar chemistry of lithium and sodium.TiO_(2)is an attra...Sodium-ion batteries(SIBs)have attracted great interest for use as the next generation rechargeable batteries due to the abundant sodium natural resources and similar chemistry of lithium and sodium.TiO_(2)is an attractive candidate as an anode for SIBs due to its high safety,low cost,appropriate voltage platform and good structural stability during repeated charge–discharge processes.However,the sodium storage mechanism of TiO_(2)for SIBs remains unclear,which appears to be different from the working mechanism in lithium-ion batteries.This article highlights a recent report by Passerini’s group,which successfully proposed a new sodium storage mechanism of TiO_(2)for SIBs.展开更多
The synergistic effect of nanoparticles(NPs)with alkyl polysulfides represents a promising avenue for enhancing extreme pressure(EP)performance in lubricants,potentially reducing the reliance on sulfur-containing addi...The synergistic effect of nanoparticles(NPs)with alkyl polysulfides represents a promising avenue for enhancing extreme pressure(EP)performance in lubricants,potentially reducing the reliance on sulfur-containing additives.However,the underlying synergistic mechanism remains unclear.In this study,oleic acidmodified titanium dioxide(TiO_(2)-OA)NPs and dialkyl pentasulfide(DPS)formed a mechanically interlocked EP tribo-film with a maximum thickness of approximately 1.4μm,demonstrating excellent load-bearing capabilities of up to 7,256 N(6.1 GPa).Under conditions of EP friction,the addition of TiO_(2)-OA NPs facilitates the development of a robust tribo-film of substantial thickness,which in turn bolsters the load-bearing capability of the lubricating oil.Surface analysis of EP wear scars using scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)revealed that TiO_(2)-OA NPs were rapidly deposited and enriched at the friction interface with increasing load(3,530‒7,256 N)and friction time(0-10 s),which in turn compensated for the in situ wear generated by extreme shear.Cross-sectional analysis of EP wear scars revealed that the preferential formation of ferrous sulfide(FeS)and subsequent rapid enrichment and mechanical interlocking of TiO_(2)-OA NPs are essential for preventing welding and improving EP performance.This study presents novel insights into the synergistic mechanisms of NPs with sulfur-containing additives,advancing the widespread implementation and progress of NPs in the field of tribology.展开更多
South Africa strengthens its efforts in polar and ocean research Under the command of Ashley Johnson,the iron gate on the starboard side of the S.A.Agulhas II vessel opened slowly,and the paired bongo nets,supported b...South Africa strengthens its efforts in polar and ocean research Under the command of Ashley Johnson,the iron gate on the starboard side of the S.A.Agulhas II vessel opened slowly,and the paired bongo nets,supported by a mechanised framework,gradually sank 100 metres into the sea.After being towed for a while,they were retrieved,and scientists on board sampled the plankton collected for analysis.Simultaneously,the bongo nets also gathered data on temperature,salinity,conductivity,and depth.Following this,the scientists deployed Niskin bottles to collect water samples from various depths.展开更多
基金Project supported by the National Natural Science Foundation of China (50974042)Scientific Research Special Foundation of Doctor Subject of Chinese Universities (20090042120015)the Fundamental Research Funds for the Central Universities (N090302007)
文摘P507 solvent extraction is the main method to separate and purify the rare earth products.The emulsification may be caused by the impurities in process of extracting rare earths,and these result in huge economic loss and decrease the quality of rare earth products.In recent researches,the extractant was prone to emulsification,and aluminum content of rare earth products also increased,while aluminum concentration of feed was higher.Pointing to this problem,the structural change of saponification P507 extracting aluminum and lanthanum was investigated by infrared spectroscopy,and the results showed that Al ions exchanged with H of P-O-H to become P-O-Al.Because aluminum held the characteristic of hydrophilic after extracted in the form of hydroxyl polymer ions and this provided conditions for the formation of micro emulsion.The organic phase and aqueous phase were investigated by polarizing microscope after aluminum was extracted.The results showed that the organic phase was clear when the extraction capacity of Al was less than 5 g/L.If the extraction capacity of Al exceeded 5 g/L,it formed W/O of ME(micro emulsion),leading to form emulsion of the organic phase.When Al concentration of feed was less than 1 g/L,the aqueous phase would form O/W of ME.If aluminum was extracted by saponification P507 firstly,then the the organic phase loading aluminum extracted rare earth continually,the organic and aqueous phase formed emulsification easily.
基金the authors thank the help of professor Liang Xiao-guangZhang Bao-wen and Tung Chen-ho of our Institute
文摘Using acridine dyes as sensitizers,the photoisomerization of three norbornadiene derivatives was investigated.The valence isomerization of nor- bornadiene derivatives(Ⅰ_a,Ⅰ_b,Ⅰ_c)gave their corresponding isomers of quadri- cyclane(Ⅱ_a,Ⅱ_b,Ⅱ_c)operating with relatively high efficiency in an electron transfer mode.Their quantum yields of isomerization were determined and the reaction mechanism was discussed.
文摘In recent years,with the continuous progress of science and technology,the development of information technology has also begun to change.The popularity of the application of modern information technology in the field of education is very high.College students can obtain the knowledge and content they need from the network.Teachers are no longer the only source of information for students,which promotes the improvement of students academic performance and cultivates students autonomous learning ability.As a university teacher,the author discusses how to motivate college students autonomous learning in the process of virtual project-based practical teaching,hoping that this paper can provide a certain direction for the future development of university education and guide college students to cultivate their autonomous learning ability.
文摘Sodium-ion batteries(SIBs)have attracted great interest for use as the next generation rechargeable batteries due to the abundant sodium natural resources and similar chemistry of lithium and sodium.TiO_(2)is an attractive candidate as an anode for SIBs due to its high safety,low cost,appropriate voltage platform and good structural stability during repeated charge–discharge processes.However,the sodium storage mechanism of TiO_(2)for SIBs remains unclear,which appears to be different from the working mechanism in lithium-ion batteries.This article highlights a recent report by Passerini’s group,which successfully proposed a new sodium storage mechanism of TiO_(2)for SIBs.
基金supported by the Shanghai Pujiang Program(No.22PJ1414700)the International Partnership Program of the Chinese Academy of Sciences(No.307GJHZ2022034GC)the Key Project of the Henan Province Science and Technology Research and Development Joint Funds(No.235101610007).
文摘The synergistic effect of nanoparticles(NPs)with alkyl polysulfides represents a promising avenue for enhancing extreme pressure(EP)performance in lubricants,potentially reducing the reliance on sulfur-containing additives.However,the underlying synergistic mechanism remains unclear.In this study,oleic acidmodified titanium dioxide(TiO_(2)-OA)NPs and dialkyl pentasulfide(DPS)formed a mechanically interlocked EP tribo-film with a maximum thickness of approximately 1.4μm,demonstrating excellent load-bearing capabilities of up to 7,256 N(6.1 GPa).Under conditions of EP friction,the addition of TiO_(2)-OA NPs facilitates the development of a robust tribo-film of substantial thickness,which in turn bolsters the load-bearing capability of the lubricating oil.Surface analysis of EP wear scars using scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)revealed that TiO_(2)-OA NPs were rapidly deposited and enriched at the friction interface with increasing load(3,530‒7,256 N)and friction time(0-10 s),which in turn compensated for the in situ wear generated by extreme shear.Cross-sectional analysis of EP wear scars revealed that the preferential formation of ferrous sulfide(FeS)and subsequent rapid enrichment and mechanical interlocking of TiO_(2)-OA NPs are essential for preventing welding and improving EP performance.This study presents novel insights into the synergistic mechanisms of NPs with sulfur-containing additives,advancing the widespread implementation and progress of NPs in the field of tribology.
文摘South Africa strengthens its efforts in polar and ocean research Under the command of Ashley Johnson,the iron gate on the starboard side of the S.A.Agulhas II vessel opened slowly,and the paired bongo nets,supported by a mechanised framework,gradually sank 100 metres into the sea.After being towed for a while,they were retrieved,and scientists on board sampled the plankton collected for analysis.Simultaneously,the bongo nets also gathered data on temperature,salinity,conductivity,and depth.Following this,the scientists deployed Niskin bottles to collect water samples from various depths.
