Elastic wave insulation and propagation control based on the programmable curved-beam periodic structure

Curved-beams can be used to design modular multistable metamaterials(MMMs)with reprogrammable material properties,i.e.,programmable curved-beam periodic structure(PCBPS),which is promising for controlling the elastic wave propagation.The PCBPS is theoretically equivalent to a spring-oscillator system to investigate the mechanism of bandgap,analyze the wave propagation mechanisms,and further form its geometrical and physical criteria for tuning the elastic wave propagation.With the equivalent model,we calculate the analytical solutions of the dispersion relations to demonstrate its adjustability,and investigate the wave propagation characteristics through the PCBPS.To validate the equivalent system,the finite element method(FEM)is employed.It is revealed that the bandgaps of the PCBPS can be turned on-and-off and shifted by varying its physical and geometrical characteristics.The findings are highly promising for advancing the practical application of periodic structures in wave insulation and propagation control.

Construction of Teaching Case Base of Anti-Seismic Design of Building Structure

Anti-Seismic Design of Building Structures is an important course in civil engineering majors,and it is also a course that pays equal attention to theory and practice.Therefore,by establishing a case base for Anti-Seismic Design of Building Structures,the obscure theoretical knowledge can be taught to students in the form of examples,and the knowledge becomes intuitive.In this way,the students’understanding of anti-seismic design theory and the efficiency of teaching can be improved,and the students’interest in learning can be stimulated.

Numerical analysis of reflective cracking and fatigue lives of semi-rigid pavement structures using ABAQUS and FE-SAFE

In order to compare the impact of thickness of different layers on fatigue lives of different semi-rigid asphalt pavement structures, the mechanical results from finite element models in ABAQUS are incorporated with the fatigue results from fatigue models in FE-SAFE to calculate the mechanical response and fatigue lives of semi-rigid pavement structures under heavy traffic loads. Then the influences on fatigue lives caused by the changes in the thickness of layers in pavement structures are also evaluated. The numerical simulation results show that the aggregated base and the large stone porous mixture （LSPM） base have better anti-cracking performance than the conventional semi-rigid base. The appropriate thickness range for the aggregated layer in the aggregated base is 15 to 18 cm. The thickness of the LSPM layer in the LSPM base is recommended to be less than 15 cm.

Syntheses,Crystal Structures and Kinetic Mechanisms of Thermal Decomposition of Rare Earth Complexes with Schiff Base Derived from o-Vanillin and p-Toluidine

Three complexes, [Pr（NO3）3（HL）2] （1）, [Nd（NO3）3（HL）2] （2） and [Er（NO3）3（HL）2] ·0.5H2O （3）, were synthesized from the reaction of a Schiff base ligand 2-[ （4-methylphenylimino）methyl ]-6-methoxyphenol （C15 H15 NO2, HL） with Ln（NO3）3·6H2O （Ln = Pr, Nd, Er）. Characterization by single-crystal X-ray diffraction technique, elemental analysis, molar conductance, FT-IR, UV-Vis, ^1H NMR and thermal analysis shows the title complexes are neutral molecules where the central Ln（ Ⅲ） ion is ten-coordinated in biapical anti-hexahedron prism geometry, with four oxygen atoms of the phenolic hydroxy and methoxy groups in the two bidentate Schiff base ligands and six oxygen atoms provided by the three bidentate NO3 - anions. Additionally, the kinetic mechanism of thermal decomposition of complex 3 was determined with a TG-DTG curves by both integral and differential methods. The functions of thermal decomposition reaction mechanism and the equation of kinetic compensation effect were obtained.

Syntheses, Crystal Structures and Antibacterial Activities of Schiff Base Ligand and Its Nickel(Ⅱ) Complex

A complex [NIL2] was synthesized, in which L, or to be exact, a Schiff base ligand （HL）, was derived from the condensation of 1-phenyl-3-methyl-4-phenylacetyl-5-pyrazolone （PMPAP） with L-phenylalanine methyl ester. They were characterized by IR and single-crystal X-ray diffraction. Green block crystals of both ligand and its complex were grown at room temperature. The ligand, which consists of two individual fragments, crystalizes in the P1 space group （a = 5.6268（5）, b = 10.6892（11） and c = 19.4869（18） A）. The complex crystalizes in the P21 space group （a -- 21.4076（18）, b = 9.4792（8） and c = 25.287（2） A）, which consists of a nickel six-coordinated compound. Every fragment is a distorted octahedron with four oxygen and two nitrogen atoms. The Schiff base ligand （HL） and its complex have been tested in vitro to evaluate their antibacterial activity against bacteria Escherichia Coli and Bacillus subtilis. It is found that the complex has higher activity than the corresponding free Schiff base ligand （HL） against the same bacterial.

Synthesis, Crystal Structure and Cytotoxic Activity of a Novel Nickel(II) Complex with Schiff Base Derived from Salicylhydrazide

A novel Schiff base complex with π-conjugated system, [Ni（L1）2（py）2] 1 （L1 =（E）-N′-（2,4-dichlorobenzylidene）-2-oxidobenzohydraizide）, was synthesized and characterized by elemental analysis and single-crystal X-ray determination. Complex 1 crystallizes in the monoclinic system, space group P21/n with a = 12.8286（10）, b = 16.3573（13）, c = 19.0206（14） A, β = 108.2920（10）°, V = 3789.6（5）A^3, Z = 4, Mr = 833.17, Dc = 1.460 g/cm^3,/t = 0.843 mm^-1, F（000） = 1704, the final R = 0.0537 and wR = 0.0640 for 3836 observed reflections with I 〉 2σ（I）. In the molecular structure of 1, the Ni^Ⅱ atoms are six-coordinated by two N and two O atoms from two Schiff base ligands （LI） and two N atoms from two pyridine solvent molecules to form a distorted octahedral geometry. The cytotoxic activities of complex 1 have been experimentally studied against a human HeLa cell in vitro.

Interface structure and formation mechanism of diffusion-bonded joints of TiAl-based alloy to titanium alloy

Vacuum diffusion bonding of a TiAl based alloy (TAD) to a titanium alloy (TC2) was carried out at 1 273 K for 15～120 min under a pressure of 25 MPa . The kinds of the reaction products and the interface structures of the joints were investigated by SEM, EPMA and XRD. Based on this, a formation mechanism of the interface structure was elucidated. Experimental and analytical results show that two reaction layers have formed during the diffusion bonding of TAD to TC2. One is Al rich α(Ti)layer adjacent to TC2,and the other is (Ti 3Al+TiAl)layer adjacent to TAD,thus the interface structure of the TAD/TC2 joints is TAD/(Ti 3Al+TiAl)/α(Ti)/TC2.This interface structure forms according to a three stage mechanism,namely(a)the occurrence of a single phase α(Ti)layer;(b)the occurrence of a duplex phase(Ti 3Al+TiAl)layer;and(c)the growth of the α(Ti)and (Ti 3Al+TiAl)layers.

Synthesis and Crystal Structure of a Zinc(II) Complex Salt with the Schiff Base of Picolinaldehyde N-oxide and Semicarbazone

The title zinc（Ⅱ） complex salt [Zn（H2O）6]（ClO4）2-（PNOS）4, where PNOS is derived from picolinaldehyde N-oxide with semicarbazone, has been prepared and structurally characterized by X-ray single-crystal analysis. It crystallizes in triclinic, space group PI with a = 7.529（3）, b = 10.206（4）, c = 14.678（6）A, a = 86.293（6）, β= 87.686（7）, γ= 81.382（6）°, C28H44Cl2N16O22Zn, Mr = 1093.06, V = 1112.3（8） ,A^3 Z = 1, Dc = 1.632 g/cm^3, S = 1.089, μ（MoKa） = 0.773 mm^-1, F（000） = 564, the final R = 0.0438 and wR = 0.1076 for 3888 independent reflections with Rint = 0.0224. The crystal structure possesses a [Zn（H2O）6]^2＋ cation, two ClO4^- anions and four PNOSs. In the crystal structure, Zn^2＋ cation is located at the symcenter and coordinated by six water molecules. In [Zn（H2O）6]^2＋, an elongate octahedral complex cation, the average Zn-O bond length is 2.087（2） A. There exist a lot of H bonds in the structure, linking the cation [Zn（H2O）6]^2＋, anion ClO4^- and PNOS to form a 3D network.

Synthesis and Crystal Structure of a New Three-dimensional Supramolecule of Copper(Ⅱ) Schiff Base Complex

A new three-dimensional supramolecule composed of copper-Schiff base complex, [Cu（naphdien）]Cl·H2O, where naphdien is Schiff base of 2-hydroxy-1-naphthaldehyde and diethylenetriamine, has been synthesized and determined by single-crystal X-ray diffraction. It belongs to the monoclinic system, space group P21/c, with a = 7.3490（15）, b = 7.0847（16）, c = 30.845（3）A, β= 95.33（3）°, V = 1599.0（5）A3, Z = 4, C15 H20ClCuN3O2, Mr = 373.33, De = 1.551 g/cm3, μ = 1.543 mm^-1, F（000） = 772, R = 0.0536 and wR = 0.0927 for 2788 unique reflections with 1659 observed ones （I 〉2σ（I））. In the crystal structure, mononuclear units [Cu（naphdien）]Cl·H2O are linked into a two-dimensional framework via strong hydrogen bonds, and extended into a three-dimensional supramolecular structure through π-π stacking interactions.

Syntheses, Characterizations, Crystal Structures and Antibacterial Activities of Two Zinc(II) Complexes with a Schiff Base Derived from o-Vanillin and p-Toluidine

Two new zinc（Ⅱ） complexes, [Zn2L2Ch].2[ZnL（CH3OH）Cl2] 1 and [ZnL2（NO3）2] 2, were synthesized by reacting ZnX2.nH2O （X = Cl^-, NO3^-） and a Schiff base ligand 2-[（4-methylphenylimino）methyl]-6-methoxyphenol （C15HIsNO2, L） which was obtained by the condensation of o-vanillin （2-hydroxy-3-methoxybenzaldehyde） with p-toluidine. Both 1 and 2 were characterized by single-crystal X-ray diffraction technique, elemental analysis, molar conductance, FT-IR, UV-Vis, IH-NMR spectra and thermogravimetrie analysis. The Schiff base ligand and its zinc（Ⅱ） complexes have been tested in vitro to evaluate their antibacterial activity against bacteria, viz., Escherichia Coli, Staphylococcus aureus and Bacillus Subtilis. The results show that these complexes have higher activity than the corresponding free Schiff base ligand against the same bacteria.

Synthesis and Crystal Structure of Complex of Zinc(Ⅱ) with Schiff Base {Zn[CH_3O(O)-C_6H_3CH_3=NN=C(S)NH_2](DMF)}_2

The title complex is a new binuclear Zn(Ⅱ) with chelate ligand of Schiff base containing S and N atom.The complex crystallizes in the orthorhombicspace group Pccn,with a=12.338(9),b=16.666(8),c=17.503(6),V=3599(6),Mr=723.52,Z=4,Dx=1.34 g/cm3,μ=15.22 cm-1,F(000)=1488.The structure was solved by direct methods and the final R=0.078.The crystal consists of discrete molecules with symmetric center at the center of the fourmembered ring consisting of two Zn atoms and two O atoms.

Synthesis and Crystal Structure of a Novel Binuclear Cu(Ⅱ) Complex with Tetradentate Schiff-base Ligand

A novel binuclear complex （[Cu^2（μ2-shed）（hshed）].（CIO4）,H2O, h2shed = N-salicylidene-N＇-（2-hydroxyethyl）ethylenediamine） has been synthesized and structurally characterized by X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/c with a = 12.511（10）, b = 15.750（12）, c = 14.281 （12） A, β = 100.564（14）°, C22H31CIN4O9Cu2, Mr = 658.04, V = 2766（4） A^3, Z = 4, Dc = 1.580 g/cm^3,μ（MoKα = 1.689 mm^-1, F（000） = 1352, the final R = 0.0528 and wR = 0.1433 for 4880 independent reflections with Rint = 0.0577. The complex is a binuclear copper compound, and two Cu（Ⅱ） ions in the binuclear cation are in different coordination environments. The Cu（1） ion adopts a distorted square pyramidal geometry （x = 0.22） with four donor atoms （N2O2） of the ligand in the basal plane, and one hydroxyl oxygen atom with protonated form occupying the apical position. The Cu（2） ion assumes the geometry of a distorted square plane with four donor atoms （N2O2） of the ligand. The Cu...Cu separation is 3.103 A,. In addition, N-H…O and C-H…O intermolecular hydrogen bonding interactions link these binuclear cations into a quasi one-dimensional chain along the a axis.

Syntheses, Crystal Structures and Antibacterial Activities of Two Heterocyclic Schiff Base Compounds

Two heterocyclic Schiff bases were synthesized via the condensation reactions of primary amines with carbonyl compounds. 2-[（4-pyridylmethylene）-amino] phenol （compound 1） was synthesized by the interaction of 4-pyridinecarboxaldehyde with o-aminophenol in ethanol solvent; N,N＇-bis（3-（furan-2-yl）allylidene）benzene-1,4-diamin （compound 2） was synthesized by the interaction of 3-（2-furyl）acrolein with p-phenylenediamine in ethanol medium. The compounds were characterized by elemental analysis, IR, MS and single-crystal X-ray diffraction. Compound 1 （C12H10N2O） crystallizes in the monoclinic system, space group P21/c with α = 7.0771（7）, b = 7.2820（7）, c = 19.849（2）, b = 96.3390（10）°, V = 1016.66（17） ？3, Z = 4, Mr = 198.22, Dc = 1.295 g/cm3, F（000） = 416, GOOF = 1.060, m = 0.085 mm-1, the final R = 0.0371 and wR = 0.0929 for 1497 observed reflections with I 〉 2σ（I）. Compound 2 （C20H16N2O2） crystallizes in the orthorhombic system, space group Fdd2 with α = 26.344（15）, b = 48.50（3）, c = 5.293（3）, V = 6764（7） ？3, Z = 16, Mr = 316.35, Dc = 1.243 g/cm3, F（000） = 2656, GOOF = 1.043, m = 0.081 mm-1, the final R = 0.0526 and wR = 0.1267 for 2059 observed reflections with I 〉 2σ（I）. 1 and 2 molecules are connected through hydrogen bonds to generate a 2D network and a 1D chain structure, respectively. The preliminary antibacterial activity results showed that the title compounds display excellent antibacterial activities to Escherichia coli, Staphylococcus aureus and Bacillus subtilis.

Synthesis, Structure and Antibacterial Activities of 4-BBTS Schiff Base and Its Complexes

4-Bromobenzaldehyde thiosemicarbazone Schiff base （4-BBTS） and its Cu（Ⅱ）, Zn（Ⅱ）, Co（Ⅱ） and Ni（Ⅱ） complexes were synthesized and characterized by elemental analysis, UV, IR, MS, ^1H NMR, and molar conductivity. Using disc diffusion method, the antibacterial activity tests were conducted. The results revealed that the ligand as well as all the complexes exhibits good antibacterial activities against E. Coli. and S. Aureus. Moreover, Cu（Ⅱ） complex shows the best antibacterial activity, which provides beneficial reference for studying the relationship between the structures and performances.

Synthesis,Crystal Structure and Quantum Chemical Investigation of Bis-Schiff Base Compounds Derived from2-phenyl-1,2,3-triazole-4-carboxaldehyde with Diamine

Two new schiff base N,N＇-bis（（2-phenyl-2H-1,2,3-triazol-4-yl）methylene）-1,3-propanediamine （1） and N,N＇-bis（（2-phenyl-2H-1,2,3-triazol-4-yl）methylene） -1,4-butanediamine （2） were synthesized by condensation of 2-phenyl-1,2,3-triazole-4-carboxaldehyde with diamine, and characterized by elemental analysis, IR, IH NMR and MS spectra. Their crystal structures were determined by X-ray single crystal diffraction. Both crystals belong to the monoclinic system, space group P21/c. For compound 1（C21H20N8, Mr=384.45）： a = 16.314（3）, b =5.7168（11）, c = 21.316（4） A, β = 105.3（2）°, Z = 4, V = 1917.6（7） A^3, De =1.332 g/cm^3, F（000） = 808,μ = 0.086 mm 1, R = 0.0533 and wR = 0.1460; for compound 2 （C22H22N8, Mr=398.48）： a = 8.6156（17）, b = 5.2964（11）, c = 22.665（5）A, β = 100.54（3）°, Z = 2, V = 1016.8（4） A^3, De= 1.302 g/cm^3, F （000） = 420, μ = 0.083 mm^-1, R = 0.0373 and wR = 0.1155. Based on the crystal data, quantum chemistry calculation was performed on the two title compounds by means of Gaussian 98 program. The molecular orbital energies and atomic net charges population were obtained. Furthermore, we antilyzed their active atoms. The investigation can serve as a theoretical guide to study the synthesis and activity of the title compounds.

Synthesis, Crystal Structure and Photoluminescence of a 2D Two-fold Interpenetrating Cd(II) Coordination Polymer Based on a Flexible Reduced Schiff Base Ligand

By the reaction of cadmium chloride with a reduced Schiff base ligand （H2L= N-（4- carboxybenzyl）-glycine）, a novel Cd（Ⅱ） compound [Cd（HL）2]·4H2O （1） has been obtained. Single-crystal X-ray diffraction analysis reveals that it crystallizes in orthorhombic, space group Pbcn with a = 13.9788（8）, b = 24.4204（14）, c = 13.9580（8） A, V= 4764.8（5） A^3, Z = 8, Mr = 600.84, Dc = 1.675 g/cm^3,/z = 0.983 mm^-1, F（000） = 2448, S = 1.084, R = 0.0806 and wR = 0.1705 （I〉 2a（1））. It displays a 2D two-fold interpenetrating structure. The Cd（Ⅱ） ions are six-coordinated. The cross-linkage of Cd（Ⅱ） ions by the bridge of HL anions results in a [Cd（HL）2] layer. Every two [Cd（HL）2]n layers are penetrated with each other, resulting in a two-fold interpenetrating double-layer structure by π-π stacking interactions and hydrogen bonds. Such double-layers are further linked by hydrogen bonds into a supramolecular structure. Photoluminescent investigation shows that compound 1 displays strong emission in the purple region.

Synthesis,Crystal Structure and Electrochemistry Properties of a Cobalt(Ⅱ) Complex Based on Asymmetry Schiff Base Ligand

A new cobalt（II） complex [Co（NO2-salen）2]·1.5H2O containing mono acetalization Schiff base ligand（NO2-salen = N-5-nitro-salicylideneamino ethanato） has been prepared through one-pot template condensation, and has been structurally characterized by elemental analysis, IR spectra and X-ray diffraction. It is formulated as C18H23CoN6O7.5, crystallizes in the hexagonal system, space group of R-3c with α = 25.895（18）, b = 25.895（18）, c = 35.075（6）, γ = 120o, V = 20368（3） and Z = 36. The ligand of 5-nitrosalicylaldehyde-ethylene-diamine takes unusual mono asymmetry mode. The Co（II） ion exhibits a coordination number of six, and assumes a distorted octahedral geometry with a N2O4 donor set. The neutral monomeric units of [Co（NO2-salen）2]·1.5H2O are linked into a one-dimensional（1D） structure via the intermolecular hydrogen bonds and weak π-π stacking interactions. Cyclic-voltammetry measurement reveals the oxidation and reduction processes for the complex are irreversible in nature.

Optimal design and effectiveness evaluation for inerter-based devices on mitigating seismic responses of base isolated structures

The optimal design and effectiveness of three control systems,tuned viscous mass damper(TVMD),tuned inerter damper(TID)and tuned mass damper(TMD),on mitigating the seismic responses of base isolated structures,were systematically studied.First,the seismic responses of the base isolated structure with each control system under white noise excitation were obtained.Then,the structural parameter optimizations of the TVMD,TID and TMD were conducted by using three different objectives.The results show that the three control systems were all effective in minimizing the root mean square value of seismic responses,including the base shear of the BIS,the absolute acceleration of structural SDOF,and the relative displacement between the base isolation floor and the foundation.Finally,considering the superstructure as a structural MDOF,a series of time history analyses were performed to investigate the effectiveness and activation sensitivity of the three control systems under far field and near fault seismic excitations.The results show that the effectiveness of TID and TMD with optimized parameters on mitigating the seismic responses of base isolated structures increased as the mass ratio increases,and the effectiveness of TID was always better than TMD with the same mass ratio.The TVMD with a lower mass ratio was more efficient in reducing the seismic response than the TID and TMD.Furthermore,the TVMD,when compared with TMD and TID,had better activation sensitivity and a smaller stroke.

Synthesis and Crystal Structure of an Azide Bridged Binuclear Zinc(Ⅱ) Dimer Containing Taurine Schiff Base [Zn_2(C_8H_9N_2O_3S)_2·(N_3)_2·(H_2O)_2]_2·_2H_2O

The title complex [Zn2L2（N3）2（H2O）2]·2H2O （L = N-（2-pyridylmethylidene） taurine） has been synthesized in a methanol-water solution. The crystal belongs to monoclinic, space group P2 1/C with a = 15.8064（10）, b = 10.5015（5）, c = 17.3193（11） ,A, β= 111.314（2）°, V = 2678.2 （3） ,A ^3 C16H26N10O10S2Zn2, Mr = 713.33, Z = 4, DC = 1.769 g/cm^3, μ = 2.017 mm^-1 and F（000） = 1456. The asymmetric unit consists of two half-molecules of the complex and two water molecules. Four N and two O atoms form the coordination environment of each Zn atom, resulting in a distorted octahedral configuration. The two halves of each independent dimer are related by a crystallographic inversion centre, which lies at the centre of the ring formed by two Zn atoms and the coordinating atoms of the two azide anions. The average separation of Zn（Ⅱ）...Zn（Ⅱ） is 3.322 A. The molecules are linked by O-H...O hydrogen bonds, generating an interesting zigzag infinite chain structure in the ac plane.

Characterization of the sequence spectrum of DNA based on the appearance frequency of the nucleotide sequences of the genome——A new method for analysis of genome structure

The nucleotide (base) sequence of the genome might reflect biological information beyond the coding sequences. The appearance frequencies of successive base sequences (key sequences) were calculated for entire genomes. Based on the appearance frequency of the key sequences of the genome, any DNA sequences on the genome could be expressed as a sequence spectrum with the adjoining base sequences, which could be used to study the corresponding biological phenomena. In this paper, we used 64 successive three- base sequences (triplets) as the key sequences, and determined and compared the spectra of specific genes to the chromosome, or specific genes to tRNA genes in Saccharomyces cerevisiae, Schizosaccharomyces pombe and Escherichia coli. Based on these analyses, a gene and its corresponding position on the chromosome showed highly similar spectra with the same fold enlargement (approximately 400-fold) in the S. cerevisiae, S. pombe and E. coli genomes. In addition, the homologous structure of genes that encode proteins was also observed with appropriate tRNA gene(s) in the genome. This analytical method might faithfully reflect the encoded biological information, that is, the conservation of the base sequences was to make sense the conservation of the translated amino acids sequence in the coding region, and might be universally applicable to other genomes, even those that consisted of multiple chromosomes.