Selection and modification of ground motion records using Newmark-Hall spectrum as target spectrum for long-period structures

Input ground motions have significant impacts on the uncertainty of structural responses in time-history analysis.In this study,records were selected and scaled for the evaluation of mean structural responses according to the target spectrum.The Newmark-Hall spectrum is closely related to seismic response of short,medium and long-period structures,so it was taken as the target spectrum here.The nonlinear time-history analyses of 9-story and 20-story steel moment-resisting frame structures were carried out as examples.They represent medium and long-period buildings,respectively.Three target spectra with risk of 50%,10%and 2%probabilities for exceedance in 50 years were calculated by the average Newmark-Hall spectrum method for three ground motion sets developed in the SAC Steel Project.The predicted structural mean responses of these Newmark-Hall spectra were compared with those calculated by the average spectral acceleration method for the same record set.It is found that both methods have similar accuracy for estimating the structural mean response.However,the method proposed herein is more effective in reducing the variability of the structural responses.Also,the proposed method is more advantageous for the time-history analysis of long-period structures or structures with more severe nonlinear responses under strong seismic excitations.

Characterization of reservoir properties and pore structure based on micro-resistivity imaging logging: Porosity spectrum, permeability spectrum, and equivalent capillary pressure curve

According to the capillary theory,an equivalent capillary model of micro-resistivity imaging logging was built.On this basis,the theoretical models of porosity spectrum(Ф_(i)),permeability spectrum(K_(i))and equivalent capillary pressure curve(pe)were established to reflect the reservoir heterogeneity.To promote the application of the theoretical models,the Archie's equation was introduced to establish a general model for quantitatively characterizing bi,K,and pei.Compared with the existing models,it is shown that:(1)the existing porosity spectrum model is the same as the general equation of gi;(2)the Ki model can display the permeability spectrum as compared with Purcell's permeability model;(3)the per model is constructed on a theoretical basis and avoids the limitations of existing models that are built only based on the component of porosity spectrum,as compared with the empirical model of capillary pressure curve.The application in the Permian Maokou Formation of Well TsX in the Central Sichuan paleo-uplift shows that the Ф_(i),K_(i),and p_(ci) models can be effectively applied to the identification of reservoir types,calculation of reservoir properties and pore structure parameters,and evaluation of reservoir heterogeneity.

Response Spectrum Analysis of 7-story Assembled Frame Structure with Energy Dissipation System

Viscoelastic damper is an effective passive damping device,which can reduce the seismic response of the structure by increasing the damping and dissipating the vibration energy of structures.It has a wide application prospect in actual structural vibration control because of simple device and economical material.In view of the poor seismic behaviors of assembled frame structure connections,various energy dissipation devices are proposed to improve the seismic performance.The finite element numerical analysis method is adopted to analyze relevant energy dissipation structural parameters.The response spectrum of a 7-story assembled frame structure combined the ordinary steel support,ordinary viscoelastic damper,and viscoelastic damper with displacement amplification device is analyzed.The analysis results show that the mechanical behavior of assembled frame structure with ordinary steel supports are not significantly different from those without energy dissipation devices.The assembled frame structure with viscoelastic damper has better seismic performance and energy dissipation,especially for the viscoelastic damper with displacement amplification devices.The maximum value of inter-story displacement angle decreases by 32.24%;the maximum floor displacement decreases by 31.91%,and the base shear decreases by 13.62%compared with the assembled frame structures without energy dissipation devices.The results show that the seismic fortification ability of the structure is significantly improved,and the overall structure is more uniformly stressed.The damping structure with viscoelastic damper mainly reduces the dynamic response of the structure by increasing the damping coefficient,rather than by changing the natural vibration period of the structure.This paper provides an effective theoretical basis and reference for improving the energy dissipation system and the seismic performance of assembled frame structures.

Nuclear magnetic resonance T_2 spectrum:multifractal characteristics and pore structure evaluation

Pore structure characteristics are important to oil and gas exploration in complex low-permeability reservoirs. Using multifractal theory and nuclear magnetic resonance （NMR）, we studied the pore structure of low-permeability sandstone rocks from the 4th Member （Es4） of the Shahejie Formation in the south slope of the Dongying Sag. We used the existing pore structure data from petrophysics, core slices, and mercury injection tests to classify the pore structure into three categories and five subcategories. Then, the T2 spectra of samples with different pore structures were interpolated, and the one- and three-dimensional fractal dimensions and the multifractal spectrum were obtained. Parameters a （intensity of singularity） andf（a） （density of distribution） were extracted from the multifractal spectra. The differences in the three fractal dimensions suggest that the pore structure types correlate with a andf（a）. The results calculated based on the multifractal spectrum is consistent with that of the core slices and mercury injection. Finally, the proposed method was applied to an actual logging profile to evaluate the pore structure of low-permeability sandstone reservoirs.

Hydrothermal Synthesis,Crystal Structure and Fluorescence Spectrum Studies of a Supramolecular Compound {[2-(2-Pyridyl)benzimidazoleH_2]^(2+)·[SbCl_5]^(2-)}_2

A new supramolecular compound, { [2-（2-pyridyl）benzimidazoleH2]2＋.[SBC15]2-}2, was synthesized by the hydrothermal reaction of o-diaminobenzene, 2-pyridinecarboxylie acid and SbCl3 in 1：1 HC1 solution, and characterized by chemical analysis, elemental analysis, IR spectra, thermogravimetfic analysis and fluorescence spectra. The crystal structure was deter- mined by X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P211c, with a = 16.0397（13）, b = 14.3189（12）, c = 15.6370（13） A, β = 105.8980（10）°, V = 3454.0（5） A3, Z = 4, C24H22Cl10N6Sb2, Mr = 992.48, Dc = 1.909 g/cm3,/z = 2.366 mm-1, S = 1.010, F（000） = 1920, R = 0.0254 and wR = 0.0555. The coordination anion, [SbCl5]2- which is a distorted tetragonal pyramid, is composed by coordinating action with Sb3＋ ion and five adjacent chloride ions. Every four coordination anions of [SbCl5]2- form a biquaternion ring structure through the secondary bonding of Sb...Cl. Moreover, the compound adopts a three-dimensional network supramolecular structure because of the hydrogen bonds and π-π stacking between the rings and the 2-（2-pyridyl）benzimidazole divalent cations. The title compound also shows good fluorescent behaviors.

Synthesis, Crystal Structure and Spectrum Properties of Trinuclear Manganese Coordination Compound Mn_3(2,2'-bipy)_2(3,5-DMBA)_6

A novel complex Mn3（2,2＇-bipy）ff3,5-DMBA）6 with 3,5-dimethylbenzoic acid （3,5-DMBA） and 2,2＇-bipyridine （2,2＇-bipy） has been synthesized by means of a solvent method. It crystallizes in the monoclinic space group C2/c with a = 3.1118（6）, b = 1.1754（2）, c = 2.0887（4） nm, β = 118.50（3）°, V= 6.714（2） nm3, Dc = 1.384 g/cm3, Z = 8, F（000） = 2912, the final GOOF = 1.078, R = 0.0691 and wR = 0.1455. The crystal structure shows that the three coordinated manganese（II） ions lie in a line with the middle one as the symmetric center. The distance between the central manganese（II） and the symmetric one is 0.3549 nm. There exist two coordination modes for the three manganese （II） ions： the symmetric manganese（II） ions are coordinated with three oxygen atoms and two nitrogen atoms from three 3,5-DMBA molecules and one 2,2＇-bipy molecule, respectively, forming a distorted square-pyramidal coordination geometry; the middle manganese（II） ion is coordinated with six oxygen atoms from six 3,5-DMBA molecules, generating a distorted octahedral coordination geometry. Spectrum properties of the complex were also studied.

Frequency Domain Fatigue Evaluation on SCR Girth-Weld Based on Structural Stress

The Steel Catenary Riser(SCR)is a vital component for transporting oil and gas from the seabed to the floating platform.The harsh environmental conditions and complex platform motion make the SCR’s girth-weld prone to fatigue failure.The structural stress fatigue theory and Master S-N curve method provide accurate predictions for the fatigue damage on the welded joints,which demonstrate significant potential and compatibility in multi-axial and random fatigue evaluation.Here,we propose a new frequency fatigue model subjected to welded joints of SCR under multiaxial stress,which fully integrates the mesh-insensitive structural stress and frequency domain random process and transforms the conventional welding fatigue technique of SCR into a spectrum analysis technique utilizing structural stress.Besides,a full-scale FE model of SCR with welds is established to obtain the modal structural stress of the girth weld and the frequency response function(FRF)of modal coordinate,and a biaxial fatigue evaluation about the girth weld of the SCR can be achieved by taking the effects of multi-load correlation and pipe-soil interaction into account.The research results indicate that the frequency-domain fatigue results are aligned with the time-domain results,meeting the fatigue evaluation requirements of the SCR.

Study on Band Structure of YbB_6 and Analysis of Its Optical Conductivity Spectrum

The electronic structure of YbB6 crystal was studied by means of density functional （GGA ＋ U） method. The calculations were performed by FLAPW method. The high accurate band structure was achieved. The correlation between the feature of the band structure and the Yb-B6 bonding in YbB6 was analyzed. On this basis, some optical constants of YbB6 such as reflectivity, dielectric function, optical conductivity, and energy-loss function were calculated. The results are in good agreement with the experiments. The real part of the optical conductivity spectrum and the energy-loss function spectrum were analyzed in detail. The assignments of the spectra were carried out to correlate the spectral peaks with the interband electronic transitions, which justify the reasonable part of previous empirical assignments and renew the missed or incorrect ones.

Electronic structure and infrared spectrum of a W_n C^(0,±) (n = 1-6) cluster

WnC0＇± （n= 1-6） clusters are investigated by using the density functional theory （DFT） at the B3LYP/LANL2DZ level. We find that the neutral, anionic and cationic ground state structures are similar within the same size, and constituted by substituting a C atom for one W atom in the structures of Wn＋1 clusters. The natural bond orbital （NBO） charge analyses indicate that the direction of electron transfer is from the W atom to the 2p orbital of the C atom. In addition, the calculated infrared spectra of the WnC0＇± （n= 2-6） clusters manifest that the vibrational frequencies of neutral, anionic and cationic clusters are similar in a range of 80 cm-1-864 cm-1. The high frequency, strong peak modes are found to be an almost stretched deformation of the carbide atom. Finally, the polarizabilities of WnC0＇± （n= 1-6） clusters are also discussed.

Topography Structure and Scanning Tunneling Spectrum of Nickel( Ⅱ )-tetraphenylporphyrin Molecules on Au(111)

Scanning tunneling microscopy （STM） and scanning tunneling spectroscopy （STS） were performed on monolayer film of NiTPP supported on Au（111） under ultrahigh vacuum （UHV） conditions. The constant current STM images show remarkable bias dependence. High resolution STM data clearly show the individual NiTPP molecules and allow easy differentiation between NiTPP and CoTPP reported before. Scanning tunneling spectra, as a function of molecule-tip separation, were acquired over a range of tip motion of 0.42 nm. Spectra do not show the variation in band splitting with tip distance. It appears for molecules such as NiTPP that the average potential at the molecule is essentially the same at the same metal substrate. For molecules of the height of NiTPP, the scanning tunneling spectra should give reliable occupied and unoccupied orbital energies over a wide range of tip-molecule distances.

Spectrum spatial structure characteristic analysis of remote sensing alteration information and interference factors

Based on the statistical characteristics of remote sensing data, the spatial geometric structure characteristics of spectral data and distribution of background, interference and alteration information in characteristic space were researched through the analysis of two-dimensional and three-dimensional scatter diagrams. The results indicate that the hyper-space of remote sensing multi-data aggregation belongs to low-dimensional geometric structure, i.e. hyperplane form, and anomalous point groups including alteration information usually dissociate out of hyperplane. Scatter diagrams of remote sensing data band are mainly presented as two distribution forms of single-ellipse and dual-ellipse. Clarifying the relations of three objects of background, disturbance and alteration information in remote sensing images provides an important technical thought and guidance for accurately detecting and extracting remote sensing alteration information.

Role of Ordering Energy in Formation of Grain Structure and Special Boundaries Spectrum in Ordered Alloys with L12 Superstructure

It was revealed that an average energy of special boundaries is proportional to APB energy in the alloys with the L12 superstructure. This fact proves the appearance of the GAPBs in the planes of location of special boundaries in coincidence sites of ordered alloys. It was determined that the more energy of special boundaries in ordered alloys, the more energy of complex stacking fault. There is a correlation between the distribution of special boundaries as a function its relative energy and ordering energy: the more ordering energy, the more degree of washed away of distribution. The correlation between average relative energy of special boundaries and ordering energy was detected: the more ordering energy, the more average energy of special boundaries. The reverse dependence between ordering energy and average number of special boundaries in grains limited by boundaries of general type was discovered.

Crystal Structure and Spectrum Character of Bis[1-(4-Methoxyphenyl)-3-(1H-1,2,4-Triazol-1-yl)-1-Propanone] dichorozinc(Ⅱ) Complex

The titled new complex was synthesized and determined by X-ray diffraction. The crystal belongs to monoclinic, P-I group, a=1.8997（4）nm, b-0.581 07（12）nm, c=2.4209（5）nm, β-90.65（3）°, V=2.672 2（9） nm^3, Z=4, Dc= 1.488 g/cm^3, It has C2 symmetry with the axis through the Zn atom, and the zinc atom is coordinated by two N atoms of the 1-（4-methoxyphenyl） 3-（ 1H-1, 2, 4-triazol-1-yl）-1-propanone ligands and two C1^- atoms, forming a slightly distorted tetrahedron. Intermolecular hydrogen bonds make the complex stable. IR and electronic spectra study of the target complex were also carried.

Crystal Structure and Raman Spectrum of Neodymium（Ⅲ） Complex of p－Aminobenzoic Acid and 1，10－Phenanthroline

Crystal structure of tetra(1,10-Phenanthroline)neodymium (Ⅲ) tetra(4-aminobenzoate)-hydrate, [Nd(p-ABA)4·2Phen]H+3O·2Phen (p-ABA:p-aminobenzoate,Phen:1,10-phenanthroline) has been determined by X-ray diffraction.The complex crystallizes in monoclinic, space group C2/c.The cell dimensions are a=1.9067 (5) nm,b=1.9192 (3) nm,c=2.0190 (4) nm,β=117.25 (2) °.V=6.568 (3) nm3, Mr= 1428.63,Z=4 and Dx= 1.45 g·cm-3.The coordination number of Nd atom is 10, and the coordinated polyhedron around the Nd atom is distorted trigonal prism.

Synthesis，Crystal Structure and Infrared Spectrum of Lanthanum Dinuclear Coordination Compound with Alanine：〔La2（ala）4（H2O）8〕·（ClO4）6

Lanthanum coordination compound with l-alanine[La2（ala）4（H2O）8]·（ClO4）6（ala=l-alanine） was synthesized by reaction of lanthanum perchlorate with l-alanine in aqueous solution and obtained in the form of single crystals.The X-ray crystal structure has been determined and the IR spectrum has been studied.The title compound Cl6La2C12H44O40N4,Mr=1375.2,crystallizes in the triclinic,space group P1 , with parameters: a= 11.227（3）,b=11.445（2）,c=11.014（3）,α=114.46（2）,β=114.51（2）,γ=78.62（2）°,V=1171.73,Z=1,Dc=1.95 g/cm￣3,F（000）=680,μ=22.9 cm￣-1（MoKα）.The final R=0.050,Rω=0.051.In the crystal,two lanthanum ions are coordinated by four alanine molecules via four carboxylate bridges to form a dinuclear coordination compound.Four water molecules are coordinated to each lanthanum ion. There is a symmetric centre between the two lanthanum ions.The IR spectrum of the coordination compound and the relationship between the IR spectrum and the structure have been studied.The mechanism of the configuration inversion of alanine has been proposed.

DEFORMATION OF STRUCTURE AND SPECTRUM OF EVOLUTION EQUATIONS

In this paper, we study the general structure of evolution equations of the AKNS eigenvalue problem q(x,t), r(x,t) with the spectrum varying asand AV BV CV are all positive or negative power polynomials of where q, r are not limited with any additional conditions at infinity.

Impact of the Opto-Geometric Parameters on the Band Diagram and Transmission and Reflection Spectrum of the Bragg Structure

Knowledge of the band gap and transmission and reflection spectrum of a photonic crystal is essential elements for their design. A graphical interface that quickly determines the banding pattern and spectrum based on the Plane Wave Method (PWM) and coupled modes method (CMM) respectively is created. It is used to explore the behavior of a Bragg structure with the ability to easily vary the important parameters such as refractive indices, number and thickness of layers.

Coherent Features of Resonance-Mediated Two-Photon Absorption Enhancement by Varying the Energy Level Structure,Laser Spectrum Bandwidth and Central Frequency

The femtosecond pulse shaping technique has been shown to be an effective method to control the multi-photon absorption by the light–matter interaction. Previous studies mainly focused on the quantum coherent control of the multi-photon absorption by the phase, amplitude and polarization modulation, but the coherent features of the multi-photon absorption depending on the energy level structure, the laser spectrum bandwidth and laser central frequency still lack in-depth systematic research. In this work, we further explore the coherent features of the resonance-mediated two-photon absorption in a rubidium atom by varying the energy level structure, spectrum bandwidth and central frequency of the femtosecond laser field. The theoretical results show that the change of the intermediate state detuning can effectively influence the enhancement of the near-resonant part, which further affects the transform-limited （TL）-normalized final state population maximum. Moreover, as the laser spectrum bandwidth increases, the TL-normalized final state population maximum can be effectively enhanced due to the increase of the enhancement in the near-resonant part, but the TL-normalized final state population maximum is constant by varying the laser central frequency. These studies can provide a clear physical picture for understanding the coherent features of the resonance-mediated two-photon absorption, and can also provide a theoretical guidance for the future applications.

Crystal Structure and Spectrum Properties of a Manganese Complex with Schiff Base Ligand,Mn (bzacen) (pyrimidine) (NCS)

The title complex C_(27)H_(26)MnN_5O_2S (M_r= 539. 53 ) crystallizes in monoclinic system, space group P2_1/α with α = 8. 357 (2) A, b = 19. 077 (4) A . c = 16. 267(3) A, β=95. 85(2)°, V=2580(2) A￣3, Z=4, F(000) = 1120, D_c= 1. 39 g/ cm￣3 and μ=0. 601 mm￣(-1)(MoKα). The final R and R_w are 0. 0638 and 0. 0876, respectively. The coordination geometry around Mn atom is a distorted octahedron with a equatorial plane N_2O_2 from the Schiff base ligand bzacen￣(2-), the axial atoms being two nitrogen atoms from a thiocyanate and a pyrimidine ligand. The shifts of v_c=N, v_c=O and v_c=C to lower frequencies in IR and Raman spectra indicate that the ligand bzacen￣(2-) has been coordinated to Mn atom through its nitrogen and oxygen atoms. The lines assigned to Mn-O and Mn-N vibrations were found in Raman spectrum. There is π～π￣* transition, d～π￣* charge-transfer transitions and d～d￣* transitions in electronic spectrum. The current potential curve in acetontrile reveals that Mn(Ⅲ)is in stable valence state.

Spectroscopy Study on Crystal Structure of Ce(NO_3)_3(phen)_2 and Interactions of Ce(NO_3)_3(phen)_2 with DNA

The absorption, fluorescence and Raman spectra of Ce(NO3)(3)(phen)(2) complex were assigned and the crystal structure of the complex was studied. Meanwhile the interactions between Cc (NO3)(3) (phen)(2) and DNA were studied by spectrum methods. As DNA was added, it is found that both the UV absorption bands of Ce(NO3)(3)(phen)(2) and the SERS bands of Ce(NO3)(3)(phen)(2) weaken evidently, while the fluorescence intensity of Ce(NO3)(3)(phen)(2) enhance dramatically. The complex compete against EB on the reaction with DNA. It is indicated by this spectrum methods that there are strong interactions between Ce(NO3)(3)(phen)(2) and DNA, and the bond mode is intercalation. The bond constant of the complex with DNA is determined to be 1.7 x 10(5).