Previous studies have demonstrated linear polymers embedded with B←N units display efficient photocatalytic hydrogen evolution performance,but their limited structural tunability restricts photogenerated carrier dyna...Previous studies have demonstrated linear polymers embedded with B←N units display efficient photocatalytic hydrogen evolution performance,but their limited structural tunability restricts photogenerated carrier dynamics modulation.Current researches mainly focus on linear polymers,while the study of B←N units in the field of two-dimension conjugated polymers(2DCPs)photocatalytic hydrogen evolution remains an uncultivated ground.Herein,three 2DCPs containing B←N units were synthesized and their photocatalytic hydrogen production performance was investigated.Among them,the BN-Tz exhibited the best property with a hydrogen production rate of 89.5μmol·h^(-1),while BN-Ph and BN-TPB were only 26.4 and 8.5μmol·h^(-1),respectively.Comprehensive analyses showed that the remarkable photocatalytic ability of BN-Tz catalyst was mainly attributed to its superior transport and separation of photogenerated carriers,as well as the ability to construct a stronger built-in electric field and better planarity.Meanwhile,it was found that the manipulation of the electronic properties of the structures connected to the B←N unit could effectively regulate the molecular polarity,thus achieving the control of the electronic structure of the materials.This work extends the application of materials containing B←N units in photocatalysis and lays a good foundation for the subsequent design of photocatalysts containing B←N units.展开更多
We investigate an N-unit series system with finite number of vacations. By analyzing the spectral distribution of the system operator and taking into account the irreducibility of the semigroup generated by the system...We investigate an N-unit series system with finite number of vacations. By analyzing the spectral distribution of the system operator and taking into account the irreducibility of the semigroup generated by the system operator we prove that the dynamic solution converges strongly to the steady state solution. Thus we obtain asymptotic stability of the dynamic solution of the system.展开更多
We investigate the solution of an N-unit series system with finite number of vacations. By using C0-semigroup theory of linear operators, we prove well-posedness and the existence of the unique positive dynamic soluti...We investigate the solution of an N-unit series system with finite number of vacations. By using C0-semigroup theory of linear operators, we prove well-posedness and the existence of the unique positive dynamic solution of the system.展开更多
A series of liquid crystalline polymers with two-dimensional mesogenic units were synthesized by solution polycondensation at low temperature. All the polymers were liquid crystalline. The melting temperature T;（exce...A series of liquid crystalline polymers with two-dimensional mesogenic units were synthesized by solution polycondensation at low temperature. All the polymers were liquid crystalline. The melting temperature T;（except that with substituent of methoxy） and the clearing temperature T;of the polymers change regularly with varying of the length of the alkyl substituent groups.展开更多
The general strategy to construct D-A type conjugated polymers is alternating copolymerization of electron-donating(D)monomer and electron-accepting(A)monomer.In this article,we report a new strategy to develop D-A ty...The general strategy to construct D-A type conjugated polymers is alternating copolymerization of electron-donating(D)monomer and electron-accepting(A)monomer.In this article,we report a new strategy to develop D-A type conjugated polymers,i.e.first fuse the D and A units into a polycyclic structure to produce a building block and then polymerize the building block with another unit.We develop a new building block with ladder structure based on B←N unit,B←N bridged dipyridylbenzene(BNDPB).In the skeleton of BNDPB,one diamine-substituted phenylene ring(D unit)and two B←N-linked pyridyl rings(A unit)are fused together to produce the polycyclic structure.Owning to the presence of intramolecular D-A character,the building block itself exhibits narrow bandgap of 1.74 eV.The conjugated polymers based on BNDPB show unique electronic structures,i.e.localized HOMOs and delocalized LUMOs,which are rarely observed for conventional D-A conjugated polymers.The polymers exhibit smaller bandgap than that of the building block BNDPB and display near-infrared(NIR)light absorption(λabs=ca.700 nm).This study thus provides not only a new strategy to design D-A conjugated polymers but also a new kind of building block with narrow bandgap.展开更多
Two series of new liquid crystalline polymers with T-shaped two-dimensional mesogenic units were synthesized by low temperature solution polycondensations of 4-substituted N-2, 5-dihydroxybenzylidene aniline monomers ...Two series of new liquid crystalline polymers with T-shaped two-dimensional mesogenic units were synthesized by low temperature solution polycondensations of 4-substituted N-2, 5-dihydroxybenzylidene aniline monomers with different diacyl dichlorides. The polymers were found to be nematic and shown liquid crystalline behavior. The melting temperature T-m and the clearing temperature T-i of the polymers change regularly with varying of the monomer structures.展开更多
Different function spaces have certain inclusion or equivalence relations. In this paper, the author introduces a class of Möbius-invariant Banach spaces QK,0 (p,q) of analytic function on the unit ball of Cn...Different function spaces have certain inclusion or equivalence relations. In this paper, the author introduces a class of Möbius-invariant Banach spaces QK,0 (p,q) of analytic function on the unit ball of Cn, where K:(0,∞)→[0,∞) are non-decreasing functions and 0P∞, p/2-n-1q∞, studies the inclusion relations between QK,0 (p,q) and a class of B0α spaces which was known before, and concludes that QK,0 (p,q) is a subspace of B0(q+n+1)/p, and the sufficient and necessary condition on kernel function K(r) such that QK,0 (p,q)= B0(q+n+1)/p.展开更多
The development of donor-acceptor(D-A)type conjugated polymers depends largely on the design of novel A building blocks.Herein,we report a novel A building block based on the cyano-substituted organoboron unit(SBN-3)....The development of donor-acceptor(D-A)type conjugated polymers depends largely on the design of novel A building blocks.Herein,we report a novel A building block based on the cyano-substituted organoboron unit(SBN-3).Compared with the most common fluorine-substituted B←N unit,SBN-3 displays a significantly downshifted LUMO energy level because of the strong electron-withdrawing ability of cyano groups.In addition,due to the greater impact of cyano substitution on LUMO than on HOMO,SBN-3 exhibits a reduced band gap,nearinfrared absorption and fluorescence properties.The D-A type conjugated polymers based on the cyano-substituted B←N unit with thiophene-based units show narrow optical band gaps of ca.1.3 e V as well as distinctive electronic structures,i.e.,delocalized LUMOs and localized HOMOs.This work thus provides not only an effective approach to design strong A units but also a new electron-deficient building block for D-A type conjugated polymers.展开更多
基金supported by the National Key R&D Program of China(2023YFA1506800-2023YFA1506804)the National Natural Science Foundation of China(Nos.22171111 and 22071093)+1 种基金the Fundamental Research Funds for the Central Universities(lzujbky-2017-k07)the China Northern Rare Earth(Group)High-Tech Co.,Ltd.(No.BFXT-2023-D-0046)。
文摘Previous studies have demonstrated linear polymers embedded with B←N units display efficient photocatalytic hydrogen evolution performance,but their limited structural tunability restricts photogenerated carrier dynamics modulation.Current researches mainly focus on linear polymers,while the study of B←N units in the field of two-dimension conjugated polymers(2DCPs)photocatalytic hydrogen evolution remains an uncultivated ground.Herein,three 2DCPs containing B←N units were synthesized and their photocatalytic hydrogen production performance was investigated.Among them,the BN-Tz exhibited the best property with a hydrogen production rate of 89.5μmol·h^(-1),while BN-Ph and BN-TPB were only 26.4 and 8.5μmol·h^(-1),respectively.Comprehensive analyses showed that the remarkable photocatalytic ability of BN-Tz catalyst was mainly attributed to its superior transport and separation of photogenerated carriers,as well as the ability to construct a stronger built-in electric field and better planarity.Meanwhile,it was found that the manipulation of the electronic properties of the structures connected to the B←N unit could effectively regulate the molecular polarity,thus achieving the control of the electronic structure of the materials.This work extends the application of materials containing B←N units in photocatalysis and lays a good foundation for the subsequent design of photocatalysts containing B←N units.
文摘We investigate an N-unit series system with finite number of vacations. By analyzing the spectral distribution of the system operator and taking into account the irreducibility of the semigroup generated by the system operator we prove that the dynamic solution converges strongly to the steady state solution. Thus we obtain asymptotic stability of the dynamic solution of the system.
文摘We investigate the solution of an N-unit series system with finite number of vacations. By using C0-semigroup theory of linear operators, we prove well-posedness and the existence of the unique positive dynamic solution of the system.
基金This work was supported by the FEYUT, SEDC, CHINA and by the National Natural Science Foundation of China.
文摘A series of liquid crystalline polymers with two-dimensional mesogenic units were synthesized by solution polycondensation at low temperature. All the polymers were liquid crystalline. The melting temperature T;（except that with substituent of methoxy） and the clearing temperature T;of the polymers change regularly with varying of the length of the alkyl substituent groups.
基金supported by the National Natural Science Foundation of China (21625403, 21822507, 21875244, 21761132020, 21574129)National Key Research and Development Program of China (2018YFE0100600)+2 种基金funded by MOST and Strategic Priority Research Program of CAS (XDB12010200)Youth Innovation Promotion Association of CAS (2017265)State Key Laboratory of Supramolecular Structure and Materials in Jilin University (sklssm201905)
文摘The general strategy to construct D-A type conjugated polymers is alternating copolymerization of electron-donating(D)monomer and electron-accepting(A)monomer.In this article,we report a new strategy to develop D-A type conjugated polymers,i.e.first fuse the D and A units into a polycyclic structure to produce a building block and then polymerize the building block with another unit.We develop a new building block with ladder structure based on B←N unit,B←N bridged dipyridylbenzene(BNDPB).In the skeleton of BNDPB,one diamine-substituted phenylene ring(D unit)and two B←N-linked pyridyl rings(A unit)are fused together to produce the polycyclic structure.Owning to the presence of intramolecular D-A character,the building block itself exhibits narrow bandgap of 1.74 eV.The conjugated polymers based on BNDPB show unique electronic structures,i.e.localized HOMOs and delocalized LUMOs,which are rarely observed for conventional D-A conjugated polymers.The polymers exhibit smaller bandgap than that of the building block BNDPB and display near-infrared(NIR)light absorption(λabs=ca.700 nm).This study thus provides not only a new strategy to design D-A conjugated polymers but also a new kind of building block with narrow bandgap.
基金Tins work was supported by the National Natural Science Foundation of China.
文摘Two series of new liquid crystalline polymers with T-shaped two-dimensional mesogenic units were synthesized by low temperature solution polycondensations of 4-substituted N-2, 5-dihydroxybenzylidene aniline monomers with different diacyl dichlorides. The polymers were found to be nematic and shown liquid crystalline behavior. The melting temperature T-m and the clearing temperature T-i of the polymers change regularly with varying of the monomer structures.
文摘Different function spaces have certain inclusion or equivalence relations. In this paper, the author introduces a class of Möbius-invariant Banach spaces QK,0 (p,q) of analytic function on the unit ball of Cn, where K:(0,∞)→[0,∞) are non-decreasing functions and 0P∞, p/2-n-1q∞, studies the inclusion relations between QK,0 (p,q) and a class of B0α spaces which was known before, and concludes that QK,0 (p,q) is a subspace of B0(q+n+1)/p, and the sufficient and necessary condition on kernel function K(r) such that QK,0 (p,q)= B0(q+n+1)/p.
基金financially supported by the National Natural Science Foundation of China(Nos.22135007,21875244 and 52073281)Jilin Scientific and Technological Development Program(No.YDZJ202101ZYTS138)。
文摘The development of donor-acceptor(D-A)type conjugated polymers depends largely on the design of novel A building blocks.Herein,we report a novel A building block based on the cyano-substituted organoboron unit(SBN-3).Compared with the most common fluorine-substituted B←N unit,SBN-3 displays a significantly downshifted LUMO energy level because of the strong electron-withdrawing ability of cyano groups.In addition,due to the greater impact of cyano substitution on LUMO than on HOMO,SBN-3 exhibits a reduced band gap,nearinfrared absorption and fluorescence properties.The D-A type conjugated polymers based on the cyano-substituted B←N unit with thiophene-based units show narrow optical band gaps of ca.1.3 e V as well as distinctive electronic structures,i.e.,delocalized LUMOs and localized HOMOs.This work thus provides not only an effective approach to design strong A units but also a new electron-deficient building block for D-A type conjugated polymers.
