This article analyzes the enlightenment of studying the German"dual system"under the new situation for our country's promotion of enterprises to participate in vocational education and elaborates on the ...This article analyzes the enlightenment of studying the German"dual system"under the new situation for our country's promotion of enterprises to participate in vocational education and elaborates on the nature of German"dual system"of skills training,the core role of enterprises and the motivation of economic subsidies.Based on expounding the current situation of our vocational education,this article focuses on the analysis of key issues affecting the quality of vocational education in our country and the reasons why Chinese enterprises lack motivation to participate in vocational education.Finally,based on the enlightenment of Germany's"dual system",it is pointed out that our country's vocational education reform should adopt effective measures of economic subsidies to strengthen the motivation of enterprises to participate in vocational education.展开更多
Metal−nitrogen double bonds have been commonly reported for conventional metal complexes,but the coexistence of both transition metal−nitrogen and lanthanide−nitrogen double bonds bridged by nitrogen within one compou...Metal−nitrogen double bonds have been commonly reported for conventional metal complexes,but the coexistence of both transition metal−nitrogen and lanthanide−nitrogen double bonds bridged by nitrogen within one compound has never been reported.Herein,by encapsulating a ternary transition metallanthanide heteronuclear dimetallic nitride into a C_(84) fullerene cage,transition metal−nitrogen and lanthanide-nitrogen double bonds are costabilized simultaneously within the as-formed clusterfullerene TiCeN@C_(1)(12)-C_(84),which is a representative heteronuclear dimetallic nitride clusterfullerene.Its molecular structure was unambiguously determined by single-crystal X-ray diffraction,revealing a slightly bentμ2-bridged nitride cluster with short Ti−N(1.761Å)and Ce−N(2.109Å)bond lengths,which are comparable to the corresponding Ti=N and Ce=N double bonds of reported metal complexes and consistent with the theoretically predicted values,confirming their coexistence within TiCeN@C_(1)(12)-C_(84).Density functional theory(DFT)calculations unveil three-center two-electron(3c-2e)bonds delocalized over the entire TiCeN cluster,which are responsible for costabilization of Ti�N and Ce�N double bonds.An electronic configuration of Ti4+Ce^(3+)N^(3−)@C_(84)^(4−)is proposed featuring an intramolecular four-electron transfer,drastically different from the analogous actinide dimetallic nitride clusterfullerene(U_(2))^(9+)N^(3−)@C_(80)^(6−)and trimetallic nitride clusterfullerene(Sc_(2))^(6+)Ti^(3+)^(N3−)@C_(80)^(6−),indicating the peculiarity of 4-fold negatively charged fullerene cage in stabilizing the heteronuclear dimetallic nitride cluster.展开更多
The low temperature is an effective method for postharvest fruits preservation.However,the ice crystal nucleation caused by low temperature significantly decreases the quality of fruits.in this paper,the effects of al...The low temperature is an effective method for postharvest fruits preservation.However,the ice crystal nucleation caused by low temperature significantly decreases the quality of fruits.in this paper,the effects of alternating magnetic field(aMF)on the ice nucleation temperature of grape were investigated,and the aMF continued treatment and aMF intermittent treatment(20 Gs,60 Hz)assisted near-freezing temperature(aMct/aMit-NFt)were used to store grapes at(−2.5±0.2)℃.compared with the untreated group,aMF decreased the ice nucleation temperature of grape 1℃.Meanwhile,results demonstrated that aMct/aMit-NFt storage improved sensory properties and antioxidant capacity of grapes,with the overall effect of aMit treatment being the most favorable.after 9 days of storage,the color difference and polyphenol oxidase(PPo)activity of aMit treatment were reduced by 17%and 12%,respectively,compared with the untreated group,and it effectively slowed down malonaldehyde(MDa)accumulation.these conclusions show that aMct/aMit-NFt storage is an effective tool for prolonging the shelf life of grapes.展开更多
基金General Scientific Research Project of the Department of Education of Zhejiang Province in 2020“Research on China Image of German Mainstream Media in the context of COVID-19”(Y202045465)Research Project of Federation of Social Sciences of Zhejiang Province in 2021“Research on China Image of Western Mainstream Media in the context of COVID-19”(2021N22)。
文摘This article analyzes the enlightenment of studying the German"dual system"under the new situation for our country's promotion of enterprises to participate in vocational education and elaborates on the nature of German"dual system"of skills training,the core role of enterprises and the motivation of economic subsidies.Based on expounding the current situation of our vocational education,this article focuses on the analysis of key issues affecting the quality of vocational education in our country and the reasons why Chinese enterprises lack motivation to participate in vocational education.Finally,based on the enlightenment of Germany's"dual system",it is pointed out that our country's vocational education reform should adopt effective measures of economic subsidies to strengthen the motivation of enterprises to participate in vocational education.
基金National Natural Science Foundation of China(51925206,U1932214,52302052,22301288)Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0450301)+2 种基金Anhui Provincial Natural Science Foundation(2308085MB33,2308085MB31)Fundamental Research Funds for the Central Universities(20720220009,WK2060000051)National Synchrotron Radiation Laboratory(KY2060000240).
文摘Metal−nitrogen double bonds have been commonly reported for conventional metal complexes,but the coexistence of both transition metal−nitrogen and lanthanide−nitrogen double bonds bridged by nitrogen within one compound has never been reported.Herein,by encapsulating a ternary transition metallanthanide heteronuclear dimetallic nitride into a C_(84) fullerene cage,transition metal−nitrogen and lanthanide-nitrogen double bonds are costabilized simultaneously within the as-formed clusterfullerene TiCeN@C_(1)(12)-C_(84),which is a representative heteronuclear dimetallic nitride clusterfullerene.Its molecular structure was unambiguously determined by single-crystal X-ray diffraction,revealing a slightly bentμ2-bridged nitride cluster with short Ti−N(1.761Å)and Ce−N(2.109Å)bond lengths,which are comparable to the corresponding Ti=N and Ce=N double bonds of reported metal complexes and consistent with the theoretically predicted values,confirming their coexistence within TiCeN@C_(1)(12)-C_(84).Density functional theory(DFT)calculations unveil three-center two-electron(3c-2e)bonds delocalized over the entire TiCeN cluster,which are responsible for costabilization of Ti�N and Ce�N double bonds.An electronic configuration of Ti4+Ce^(3+)N^(3−)@C_(84)^(4−)is proposed featuring an intramolecular four-electron transfer,drastically different from the analogous actinide dimetallic nitride clusterfullerene(U_(2))^(9+)N^(3−)@C_(80)^(6−)and trimetallic nitride clusterfullerene(Sc_(2))^(6+)Ti^(3+)^(N3−)@C_(80)^(6−),indicating the peculiarity of 4-fold negatively charged fullerene cage in stabilizing the heteronuclear dimetallic nitride cluster.
基金supported by the National Natural Science Foundation of china(51906178)Postdoctoral research Foundation of china(2022t150503).
文摘The low temperature is an effective method for postharvest fruits preservation.However,the ice crystal nucleation caused by low temperature significantly decreases the quality of fruits.in this paper,the effects of alternating magnetic field(aMF)on the ice nucleation temperature of grape were investigated,and the aMF continued treatment and aMF intermittent treatment(20 Gs,60 Hz)assisted near-freezing temperature(aMct/aMit-NFt)were used to store grapes at(−2.5±0.2)℃.compared with the untreated group,aMF decreased the ice nucleation temperature of grape 1℃.Meanwhile,results demonstrated that aMct/aMit-NFt storage improved sensory properties and antioxidant capacity of grapes,with the overall effect of aMit treatment being the most favorable.after 9 days of storage,the color difference and polyphenol oxidase(PPo)activity of aMit treatment were reduced by 17%and 12%,respectively,compared with the untreated group,and it effectively slowed down malonaldehyde(MDa)accumulation.these conclusions show that aMct/aMit-NFt storage is an effective tool for prolonging the shelf life of grapes.
