In order to investigate the influence of hydrostatic pressure on compression limit of the ring, numerical simulation and experimental research were carried out. The effect of hydrostatic pressure on the deformation of...In order to investigate the influence of hydrostatic pressure on compression limit of the ring, numerical simulation and experimental research were carried out. The effect of hydrostatic pressure on the deformation of aluminum alloy 7075 ring was obtained by numerical simulation. The die set for compressing ring under high hydrostatic pressure was designed and manufactured. Experimental results show that the compression limit increases linearly as the hydrostatic pressure increases in a certain range. At 100 MPa the maximum compressive strain is increased by 32.42%. At strain limit, the cracks initiate from the corner of the outer wall to the middle of the inner wall along the direction of the maximum shear stress.展开更多
Syntheses and properties of aluminum and titanium complexes incorporating the pyrrole-imine ligands,N-((1H-pyrrol-2-yl)methyl)-1-(1H-pyrrol-2-yl)methanimine(H2L^1)and 2-cyano-1H-pyrrole(HL^2),have been investigated.Ad...Syntheses and properties of aluminum and titanium complexes incorporating the pyrrole-imine ligands,N-((1H-pyrrol-2-yl)methyl)-1-(1H-pyrrol-2-yl)methanimine(H2L^1)and 2-cyano-1H-pyrrole(HL^2),have been investigated.Addition of one equiv of H2L^1 to AlMe3 and AlEt3,respectively results in the formation of dinuclear complexes[Al2(L^1)2 Me2](1)and[Al2(L^1)2 Et2](2).Treatment of Ti(NMe2)4 with one equiv of HL^2 and two equiv of iPrOH or three equiv of BnOH results in the production of complexes[Ti(HL^3)2(OiPr)2](3)and[Ti2(HL^3)2(OBn)6](4)(H2L^3=N,N-dimethyl-1H-pyrrole-2-carboximid-amide).HL^3 anion is an intermediate which is in situ formed from the reaction of HL^2 and Ti(NMe2)4.The structures of 1~4 were characterized by single crystal X-ray diffraction.The catalytic properties of 1~4 toward ring-opening polymerization(ROP)ofε-caprolactone were studied.All of the compounds could effectively initiate the polymerization reactions with good activities.展开更多
Ring opening copolymerization of succinic anhydride (SA) with ethylene oxide (EO)was successfully carried out by using a series of aluminum-based catalyst in 1,4-dioxane at62±2℃. The results showed that in-situ ...Ring opening copolymerization of succinic anhydride (SA) with ethylene oxide (EO)was successfully carried out by using a series of aluminum-based catalyst in 1,4-dioxane at62±2℃. The results showed that in-situ AlR_3-H_2O (R=ethyl, iso-butyl) catalysts gavehigher molecular weight (M_w～10~4), while Al(OR)_3 catalysts gave the higher alternatingcopolymer structure with slightly lower molecular weight. The in-situ AlR_3-H_2O systemshave been evaluated in more detail for the reaction which showed the optimum H_2O/Almolar ratio to be 0.5. The copolymers with different composition (F_(SA)/F_(EO)= 36/64to 45/55 mol/mol) were synthesized by using different monomer feed ratio. The melt-ing point (T_m), glass transition temperature (T_g) and enthalpy of fusion (ΔH_f) of thesecopolymers are depended on the copolymer composition and in the range of 87～102℃,-12～-18℃, and 37～66J/g, respectively. The second heating scan of DSC also in-dicated that the higher alternating copolymer was more easily recrystallized. The onsetdecomposition temperature was more than 300℃ under nitrogen and influenced by thecopolymer composition.展开更多
Based on our discovery of neutral aluminum molecular rings,we herein introduce rare earth ions into the center of the ring and reveal their structural adaptability.The resulting yoyo-like cationic macrocycles are high...Based on our discovery of neutral aluminum molecular rings,we herein introduce rare earth ions into the center of the ring and reveal their structural adaptability.The resulting yoyo-like cationic macrocycles are highly adaptive to guests,creating unusual supramolecular assemblies.The first category is stacked with singly oriented rhombohedral channels,which exhibit fast and reversible solvent-triggered molecular motions and structural rearrangements.The second type of assembly is that yoyo macrocycles and guest molecules form a nested host-guest sodalite cage supramolecular structure.It is uncommon for guest molecules to be well-defined within cages although caged structures have been well-documented.Their host-guest interaction discussion reveals the self-adaptation and flexibility of the yoyo macrocycles.Considering their good water stability,we investigated their anion exchange properties.The results show that they have significant exchange capacity for KI/I_(2),ReO_(4)^(-),and MnO_(4)^(-),revealing their potential application in water purification and nuclear waste treatment.展开更多
基金Project(HIT.2002.33) supported by the Scientific Research Foundation of Harbin Institute of Technology
文摘In order to investigate the influence of hydrostatic pressure on compression limit of the ring, numerical simulation and experimental research were carried out. The effect of hydrostatic pressure on the deformation of aluminum alloy 7075 ring was obtained by numerical simulation. The die set for compressing ring under high hydrostatic pressure was designed and manufactured. Experimental results show that the compression limit increases linearly as the hydrostatic pressure increases in a certain range. At 100 MPa the maximum compressive strain is increased by 32.42%. At strain limit, the cracks initiate from the corner of the outer wall to the middle of the inner wall along the direction of the maximum shear stress.
基金supported by the National Natural Science Foundation of China(21772140)Natural Science Foundation of Jiangsu Province(BK20171213)the Priority Academic Program Development of Jiangsu Higher Education Institution
文摘Syntheses and properties of aluminum and titanium complexes incorporating the pyrrole-imine ligands,N-((1H-pyrrol-2-yl)methyl)-1-(1H-pyrrol-2-yl)methanimine(H2L^1)and 2-cyano-1H-pyrrole(HL^2),have been investigated.Addition of one equiv of H2L^1 to AlMe3 and AlEt3,respectively results in the formation of dinuclear complexes[Al2(L^1)2 Me2](1)and[Al2(L^1)2 Et2](2).Treatment of Ti(NMe2)4 with one equiv of HL^2 and two equiv of iPrOH or three equiv of BnOH results in the production of complexes[Ti(HL^3)2(OiPr)2](3)and[Ti2(HL^3)2(OBn)6](4)(H2L^3=N,N-dimethyl-1H-pyrrole-2-carboximid-amide).HL^3 anion is an intermediate which is in situ formed from the reaction of HL^2 and Ti(NMe2)4.The structures of 1~4 were characterized by single crystal X-ray diffraction.The catalytic properties of 1~4 toward ring-opening polymerization(ROP)ofε-caprolactone were studied.All of the compounds could effectively initiate the polymerization reactions with good activities.
文摘Ring opening copolymerization of succinic anhydride (SA) with ethylene oxide (EO)was successfully carried out by using a series of aluminum-based catalyst in 1,4-dioxane at62±2℃. The results showed that in-situ AlR_3-H_2O (R=ethyl, iso-butyl) catalysts gavehigher molecular weight (M_w～10~4), while Al(OR)_3 catalysts gave the higher alternatingcopolymer structure with slightly lower molecular weight. The in-situ AlR_3-H_2O systemshave been evaluated in more detail for the reaction which showed the optimum H_2O/Almolar ratio to be 0.5. The copolymers with different composition (F_(SA)/F_(EO)= 36/64to 45/55 mol/mol) were synthesized by using different monomer feed ratio. The melt-ing point (T_m), glass transition temperature (T_g) and enthalpy of fusion (ΔH_f) of thesecopolymers are depended on the copolymer composition and in the range of 87～102℃,-12～-18℃, and 37～66J/g, respectively. The second heating scan of DSC also in-dicated that the higher alternating copolymer was more easily recrystallized. The onsetdecomposition temperature was more than 300℃ under nitrogen and influenced by thecopolymer composition.
基金supported by the National Natural Science Foundation of China(92061104,21771181,21935010)the Natural Science Foundation of Fujian Province(2021J06035)the Youth Innovation Promotion Association CAS(2017345,Y2018081)。
文摘Based on our discovery of neutral aluminum molecular rings,we herein introduce rare earth ions into the center of the ring and reveal their structural adaptability.The resulting yoyo-like cationic macrocycles are highly adaptive to guests,creating unusual supramolecular assemblies.The first category is stacked with singly oriented rhombohedral channels,which exhibit fast and reversible solvent-triggered molecular motions and structural rearrangements.The second type of assembly is that yoyo macrocycles and guest molecules form a nested host-guest sodalite cage supramolecular structure.It is uncommon for guest molecules to be well-defined within cages although caged structures have been well-documented.Their host-guest interaction discussion reveals the self-adaptation and flexibility of the yoyo macrocycles.Considering their good water stability,we investigated their anion exchange properties.The results show that they have significant exchange capacity for KI/I_(2),ReO_(4)^(-),and MnO_(4)^(-),revealing their potential application in water purification and nuclear waste treatment.
基金financial supports from the National Natural Science Foundation of China(Nos.51705248,52005517)the State Key Laboratory for High-Performance Complex Manufacturing,Central South University,China(No.ZZYJKT2021-05)+1 种基金Key Research and Development Plan of Heilongjiang Province,China(No.GA21D003)the Natural Science Foundation of Hunan Province,China(No.2020JJ4703)。
