A new series of acrylates with the same mesogens containing thioester as bridge-bond were synthesized, and the acrylates were characterized by H-1 NMR, IR and MS. The polymers were obtained by radical polymerization u...A new series of acrylates with the same mesogens containing thioester as bridge-bond were synthesized, and the acrylates were characterized by H-1 NMR, IR and MS. The polymers were obtained by radical polymerization using AIBN as initiator. The monomers and polymers exhibit thermotropic-enantiotropic Liquid crystalline behavior.展开更多
The title complex [La(betaine)2(H2O)6Fe(CN)6]?2H2O (betaine = (CH3)3NCH2CO2) has been synthesized and characterized by X-ray single-crystal structure analysis. The crystal crystallizes in monoclinic, space group P21...The title complex [La(betaine)2(H2O)6Fe(CN)6]?2H2O (betaine = (CH3)3NCH2CO2) has been synthesized and characterized by X-ray single-crystal structure analysis. The crystal crystallizes in monoclinic, space group P21/n with a = 15.793(5), b = 8.927(3), c = 22.257(7) ?, β = 110.147(5)o, C16H38FeLaN8O12, Mr = 729.31, Z = 4, V = 2946.0(15) ?3, Dc = 1.640 g/m3, μ(MoKα) = 1.988 mm-1, F(000) =1476, R = 0.0388 and wR = 0.0827 for 4237 observed reflections (I > 2σ(I)). The La3+ ion is nine-coordinated by one cyano nitrogen atom and eight oxygen atoms of two betaine and six water molecules. Each complex molecule is connected to form a 3D network structure by some O–H…O and O–H…N hydrogen bonds.展开更多
Two new bimetallic cyano-bridged complexes [Ce（DMSO）4（H2O）3Fe（CN）6]·H2O 1 and [La（DMSO）4（H20）3Co（CN）6].H20 2 have been prepared by the ball milling reaction method and structurally characterized by X-...Two new bimetallic cyano-bridged complexes [Ce（DMSO）4（H2O）3Fe（CN）6]·H2O 1 and [La（DMSO）4（H20）3Co（CN）6].H20 2 have been prepared by the ball milling reaction method and structurally characterized by X-ray single-crystal structure analyses. Crystallographic data for 1： C14H32CeFeN6O8S4, Mr= 736.67, monoclinic, space group P2 1/n, a = 14.952（1）, b = 13.7276（9）, c = 15.392（1） A, β= 108.288（1）°, V = 2999.6（4） A3, Z = 4, Dc= 1.631 g/cm^3, g = 2.304 mm^-1, F（000） = 1480, R = 0.0593 and wR = 0.1611; and those for 2： C14H32CoLaN6O8S4, Mr=738.54, monoclinic, space group P21/n, a = 14.945（3）, b = 13.731（3）, c = 15.300（3） A, β= 107.806（1）°, V= 2989.3（11） A^3, Z= 4, Dc = 1.641 g/cm^3, μ = 2.288 mm^-1, F（000） = 1480, R = 0.0383 and wR = 0.1132. In both complexes the lanthanide ion is eight-coordinated in a square antiprism arrangement, and the Fe（Ⅲ） or Co（Ⅲ） ion in a nearly regular octahedral environment The [LnM（CN）6（DMSO）4（H2O）3]·H2O （Ln = Ce and M = Fe for 1; Ln = La and M = Co for 2） species are held together via hydrogen bonds by coordinated water molecules, lattice water molecules and nitrogen atoms of cyanide groups to form a three-dimensional framework.展开更多
An offshore long-span continuous rigid-frame bridge is taken as an example to study the effect of degradation of bond-slip behavior on the seismic performance of bridges in an offshore environment during a service per...An offshore long-span continuous rigid-frame bridge is taken as an example to study the effect of degradation of bond-slip behavior on the seismic performance of bridges in an offshore environment during a service period.On the basis of a numerical simulation analysis using the OpenSeeS platform,the influence of durability degradation of concrete carbonization,steel corrosion,and degradation of bond-slip performance is considered collectively using incremental dynamic analysis method to examine the time-varying seismic fragility of the offshore bridge.Results show that when bond slip is considered,the exceedance probability of the bridge components and the system increases significantly,and the durability degradation caused by concrete carbonization and chloride ion erosion in the whole life cycle increases the seismic response of the bridge structure.The results of the proposed time-varying seismic fragility analysis indicate that,considering the degradation of bond-slip behavior of reinforced concrete after the durability degradation of materials,the exceedance probability of the pier,bearing,abutment,and system increases with the extension of service period and the increase in seismic strength under earthquake action.In addition,with the extension of service time,the effect of bond slip on the seismic fragility of components and system gradually decreases.展开更多
The dihydrogen bonds B-H...H-X （X= the complexes of NH3BH3 with HF, HCl, F, Cl, Br, C, O, N） in the dimer （NH3BH3）2 and HBr, H2CO, H20, and CH3OH were theoretically studied. The results show that formation of the ...The dihydrogen bonds B-H...H-X （X= the complexes of NH3BH3 with HF, HCl, F, Cl, Br, C, O, N） in the dimer （NH3BH3）2 and HBr, H2CO, H20, and CH3OH were theoretically studied. The results show that formation of the dihydrogen bond leads to elongation and stretch frequency red shift of the BH and XH bonds, except that in the H2CO system, the CH bond blue shifts. For （NH3BH3）2 and the complexes of the halogenides, red shifts of the XH bonds are caused by the intermolecular hyperconjugation σ（BH）→σ^＊ （XH）. For the system of H2CO, a blue shift of the CH bond is caused by a decrease of the intramolecular hyperconjugation n（O→σ^＊ （CH）. In the other two systems, the red shift of OH bond is a secondary effect of the stronger traditional red-shifted H-bonds N-H... O. In all these systems, red shifts of the BH bonds are caused by two factors： negative repolarization and negative rehybridization of the BH bond, and decrease of occupancy on σ（BH） caused by the intermolecular hyperconjugation σ（BH）→σ^＊ （XH）.展开更多
Corbels support the crossbeams of half-through arch bridges. They are prone to cracking easily due to their characteristics and complicated loading conditions. Based on a practical diagnosis of a bridge crossbeam, we ...Corbels support the crossbeams of half-through arch bridges. They are prone to cracking easily due to their characteristics and complicated loading conditions. Based on a practical diagnosis of a bridge crossbeam, we bonded steel plates onto bridge corbels to strengthen them. We carried out a numerical analysis on the effectiveness of the reinforcement by using the commercial sof^are ANSYS. The numerical analysis shows that the stresses near the section break increased slightly, but the variation amplitude was small and all the stresses were within an allowable range. The loading test indicates that it is feasible to strengthen the corbel with vertical bonded steel plates. Therefore, the reinforcement is effective and economical. This reinforcement method is suitable for this type of corbel and can be applied in similar cases.展开更多
We present a quantum-chemical analysis of the relationship between the bond length alteration （BLA） and the static first hyperpolarizability of a series of one-dimensional （1D） chromophores with donor-bridge-accep...We present a quantum-chemical analysis of the relationship between the bond length alteration （BLA） and the static first hyperpolarizability of a series of one-dimensional （1D） chromophores with donor-bridge-acceptor （D-B-A） structures. The calculated results show that the parameter BLA can be considered as an indicator to evaluate the molecular first hyper- polarizability. Along the direction of molecular ground-state dipole moments, the evolutions of BLA can be classified into three categories： the first is a non-monotonic line, which represents most chromophores; the second is monotonic increasing; and the third, contrarily, is monotonic decreasing. On the whole, the first hyperpolarizabilities of these studied chromophores are the monotonic functions of BLA along the direction of dipole moments. Therefore, the first hyperpolarizability of these 1D chromophores can be preliminarily evaluated in terms of the development of BLA without a rigorous computation. In other words, one can roughly estimate the relative magnitude of the first hyperpolarizability according to the optimized geometry.展开更多
基金Supported by Grants for Distinguished Young Teachers by the National Educational Commission of China
文摘A new series of acrylates with the same mesogens containing thioester as bridge-bond were synthesized, and the acrylates were characterized by H-1 NMR, IR and MS. The polymers were obtained by radical polymerization using AIBN as initiator. The monomers and polymers exhibit thermotropic-enantiotropic Liquid crystalline behavior.
基金Supported by the National Natural Science Foundation of China (No. 50242001)
文摘The title complex [La(betaine)2(H2O)6Fe(CN)6]?2H2O (betaine = (CH3)3NCH2CO2) has been synthesized and characterized by X-ray single-crystal structure analysis. The crystal crystallizes in monoclinic, space group P21/n with a = 15.793(5), b = 8.927(3), c = 22.257(7) ?, β = 110.147(5)o, C16H38FeLaN8O12, Mr = 729.31, Z = 4, V = 2946.0(15) ?3, Dc = 1.640 g/m3, μ(MoKα) = 1.988 mm-1, F(000) =1476, R = 0.0388 and wR = 0.0827 for 4237 observed reflections (I > 2σ(I)). The La3+ ion is nine-coordinated by one cyano nitrogen atom and eight oxygen atoms of two betaine and six water molecules. Each complex molecule is connected to form a 3D network structure by some O–H…O and O–H…N hydrogen bonds.
基金This work was supported by the NNSFC (20571075), the NSF for Distinguished Young Scientist of China (20425104) and the NSF of Fujian Province (E0510028)
文摘Two new bimetallic cyano-bridged complexes [Ce（DMSO）4（H2O）3Fe（CN）6]·H2O 1 and [La（DMSO）4（H20）3Co（CN）6].H20 2 have been prepared by the ball milling reaction method and structurally characterized by X-ray single-crystal structure analyses. Crystallographic data for 1： C14H32CeFeN6O8S4, Mr= 736.67, monoclinic, space group P2 1/n, a = 14.952（1）, b = 13.7276（9）, c = 15.392（1） A, β= 108.288（1）°, V = 2999.6（4） A3, Z = 4, Dc= 1.631 g/cm^3, g = 2.304 mm^-1, F（000） = 1480, R = 0.0593 and wR = 0.1611; and those for 2： C14H32CoLaN6O8S4, Mr=738.54, monoclinic, space group P21/n, a = 14.945（3）, b = 13.731（3）, c = 15.300（3） A, β= 107.806（1）°, V= 2989.3（11） A^3, Z= 4, Dc = 1.641 g/cm^3, μ = 2.288 mm^-1, F（000） = 1480, R = 0.0383 and wR = 0.1132. In both complexes the lanthanide ion is eight-coordinated in a square antiprism arrangement, and the Fe（Ⅲ） or Co（Ⅲ） ion in a nearly regular octahedral environment The [LnM（CN）6（DMSO）4（H2O）3]·H2O （Ln = Ce and M = Fe for 1; Ln = La and M = Co for 2） species are held together via hydrogen bonds by coordinated water molecules, lattice water molecules and nitrogen atoms of cyanide groups to form a three-dimensional framework.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51608488,11872339,11472248).
文摘An offshore long-span continuous rigid-frame bridge is taken as an example to study the effect of degradation of bond-slip behavior on the seismic performance of bridges in an offshore environment during a service period.On the basis of a numerical simulation analysis using the OpenSeeS platform,the influence of durability degradation of concrete carbonization,steel corrosion,and degradation of bond-slip performance is considered collectively using incremental dynamic analysis method to examine the time-varying seismic fragility of the offshore bridge.Results show that when bond slip is considered,the exceedance probability of the bridge components and the system increases significantly,and the durability degradation caused by concrete carbonization and chloride ion erosion in the whole life cycle increases the seismic response of the bridge structure.The results of the proposed time-varying seismic fragility analysis indicate that,considering the degradation of bond-slip behavior of reinforced concrete after the durability degradation of materials,the exceedance probability of the pier,bearing,abutment,and system increases with the extension of service period and the increase in seismic strength under earthquake action.In addition,with the extension of service time,the effect of bond slip on the seismic fragility of components and system gradually decreases.
基金ACKNOWLEDGMENT This work was supported Science Foundation of China by the National Natural （No.20873103）.
文摘The dihydrogen bonds B-H...H-X （X= the complexes of NH3BH3 with HF, HCl, F, Cl, Br, C, O, N） in the dimer （NH3BH3）2 and HBr, H2CO, H20, and CH3OH were theoretically studied. The results show that formation of the dihydrogen bond leads to elongation and stretch frequency red shift of the BH and XH bonds, except that in the H2CO system, the CH bond blue shifts. For （NH3BH3）2 and the complexes of the halogenides, red shifts of the XH bonds are caused by the intermolecular hyperconjugation σ（BH）→σ^＊ （XH）. For the system of H2CO, a blue shift of the CH bond is caused by a decrease of the intramolecular hyperconjugation n（O→σ^＊ （CH）. In the other two systems, the red shift of OH bond is a secondary effect of the stronger traditional red-shifted H-bonds N-H... O. In all these systems, red shifts of the BH bonds are caused by two factors： negative repolarization and negative rehybridization of the BH bond, and decrease of occupancy on σ（BH） caused by the intermolecular hyperconjugation σ（BH）→σ^＊ （XH）.
文摘Corbels support the crossbeams of half-through arch bridges. They are prone to cracking easily due to their characteristics and complicated loading conditions. Based on a practical diagnosis of a bridge crossbeam, we bonded steel plates onto bridge corbels to strengthen them. We carried out a numerical analysis on the effectiveness of the reinforcement by using the commercial sof^are ANSYS. The numerical analysis shows that the stresses near the section break increased slightly, but the variation amplitude was small and all the stresses were within an allowable range. The loading test indicates that it is feasible to strengthen the corbel with vertical bonded steel plates. Therefore, the reinforcement is effective and economical. This reinforcement method is suitable for this type of corbel and can be applied in similar cases.
基金the National Natural Science Foundation of China (20573114)the MOST projects of 2004CB720605and 2006DFA403020
文摘We present a quantum-chemical analysis of the relationship between the bond length alteration （BLA） and the static first hyperpolarizability of a series of one-dimensional （1D） chromophores with donor-bridge-acceptor （D-B-A） structures. The calculated results show that the parameter BLA can be considered as an indicator to evaluate the molecular first hyper- polarizability. Along the direction of molecular ground-state dipole moments, the evolutions of BLA can be classified into three categories： the first is a non-monotonic line, which represents most chromophores; the second is monotonic increasing; and the third, contrarily, is monotonic decreasing. On the whole, the first hyperpolarizabilities of these studied chromophores are the monotonic functions of BLA along the direction of dipole moments. Therefore, the first hyperpolarizability of these 1D chromophores can be preliminarily evaluated in terms of the development of BLA without a rigorous computation. In other words, one can roughly estimate the relative magnitude of the first hyperpolarizability according to the optimized geometry.
