Dianthus spiculifolius Schur,as an emerging ornamental plant,has extensive applications and economic values.In this study,the DsCBL4 gene was successfully cloned,and its tissue-specific expression,expression patterns ...Dianthus spiculifolius Schur,as an emerging ornamental plant,has extensive applications and economic values.In this study,the DsCBL4 gene was successfully cloned,and its tissue-specific expression,expression patterns under various abiotic stresses,subcellular localization,and bioinformatics analysis of the encoded amino acid sequence were conducted.The results showed that the coding region of the DsCBL4 gene was 675 bp long,encoding 224 amino acids.It had high homology with the amino acids encoded by Amaranthus tricolor,Chenopodium quinoa and Spinacia oleracea.The predicted relative molecular mass of DsCBL4 was 25.61 ku,with an isoelectric point of 4.58,and it had phosphorylation sites,belonging to an unstable hydrophilic protein.Its secondary structure includedα-helices,irregular coils and extended chains.The tertiary structure prediction revealed that DsCBL4 had four EFhand calcium-binding domains necessary for Ca2+binding in plant calmodulin-like proteins and the FPSF motif for calcineurin B-like protein(CBL)-interacting protein kinase(CIPK)activation.The expression level of the DsCBL4 gene showed tissue specificity,with the highest expression in roots.It was induced by drought,low temperature,combined drought and low temperature,salt stress,nitrogen stress,phosphorus stress,calcium ion stress,high temperature stress,and abscisic acid(ABA)stress.Both transient infection in Nicotiana tabacum L.and stable expression in transgenic Arabidopsis thaliana showed that the DsCBL4 protein was localized to the cell membrane.These results suggested that DsCBL4 might be involved in the abiotic stress response of Dianthus spiculifolius through the calcium signaling pathway,providing a theoretical basis for understanding its molecular mechanism.This study provided an important reference for further exploring the role of the DsCBLs gene family in plant stress resistance.展开更多
Neurodegenerative disorders,including Alzheimer’s disease(AD),Parkinson’s disease(PD),and amyotrophic lateral sclerosis,impose a considerable social and economic burden on society and have dramatic consequences for ...Neurodegenerative disorders,including Alzheimer’s disease(AD),Parkinson’s disease(PD),and amyotrophic lateral sclerosis,impose a considerable social and economic burden on society and have dramatic consequences for individuals and their families.The majority of existing interventions have been found to be capable of only a slight modification of disease progression or to moderately delay significant functional decline in motor,cognitive,or mental domains.展开更多
An optimization method for the consistent evaluation of two Rayleigh damping coefficients is proposed. By minimizing an objective function such as an error term of the peak displacement of a structure, the two coeffic...An optimization method for the consistent evaluation of two Rayleigh damping coefficients is proposed. By minimizing an objective function such as an error term of the peak displacement of a structure, the two coefficients can be determined with response spectral analysis. The optimization method degenerates into the conventional method used in current practices when only two modes of vibration are included in the objective function. Therefore, the proposed method with all significant modes included for simplicity in practical applications results in suboptimal damping coefficients. The effects of both spatial distribution and frequency content of excitations as well as structural dynamic characteristics on the evaluation of Rayleigh damping coefficients were investigated with a five-story building structure. Two application examples with a 62-story high-rise building and a 840 m long cable-stayed bridge under ten earthquake excitations demonstrated the accuracy and effectiveness of the proposed method to account for all of the above effects.展开更多
In the tubular frames with simple joints, the joints may show considerable local flexibility, which causes excessive deformation and affects internal force distributions. It is useful and important to study turbular j...In the tubular frames with simple joints, the joints may show considerable local flexibility, which causes excessive deformation and affects internal force distributions. It is useful and important to study turbular joint flexibility as well as the effect of joint local flexibility on the global behavior of tubular structure for the design and building of offshore platforms. A new method for computing the stiffness coefficients of simple tubular joints is developed in this paper based on two previous computing models. According to this method, the local flexibility of T, Y, TY tubular joints are computed. This method has merits of clear physical sense, simplicity of computations and less c.p.u. time. The effect of flexibility of tubular joints on the global behavior of framed tubular structures is investigated by comparing the computed results of tubular structures with flexible tubular joints with those with rigid connections. The comparison shows that the consideration of local flexibility of tubular joints and its effect on the stress analysis of offshore structures has its practical significance.展开更多
For the safety protection of passengers when train crashes occur, special structures are crucially needed as a kind of indispensable energy absorbing device. With the help of the structures, crash kinetic-energy can b...For the safety protection of passengers when train crashes occur, special structures are crucially needed as a kind of indispensable energy absorbing device. With the help of the structures, crash kinetic-energy can be completely absorbed or dissipated for the aim of safety. Two composite structures(circumscribed circle structure and inscribed circle structure) were constructed. In addition, comparison and optimization of the crashworthy characteristic of the two structures were carried out based on the method of explicit finite element analysis(FEA) and Kriging surrogate model. According to the result of Kriging surrogate model, conclusions can be safely drawn that the specific energy absorption(SEA) and ratio of specific energy absorption to initial peak force(REAF) of circumscribed circle structure are lager than those of inscribed circle structure under the same design parameters. In other words, circumscribed circle structure has better performances with higher energy-absorbing ability and lower initial peak force. Besides, error analysis was adopted and the result of which indicates that the Kriging surrogate model has high nonlinear fitting precision. What is more, the SEA and REAF optimum values of the two structures have been obtained through analysis, and the crushing results have been illustrated when the two structures reach optimum SEA and REAF.展开更多
In this paper, the generalized variational principle of dynamic analysis for the blast-resistant underground structures is established, and the corresponding generalized functional of elastoplastic analysis for underg...In this paper, the generalized variational principle of dynamic analysis for the blast-resistant underground structures is established, and the corresponding generalized functional of elastoplastic analysis for underground structures is derived, and the generalized variational principle of nonconservative system is given, thus the fundamental of dynamical analysis for underground structures to resist blast is proposed. Finally, for the underground cylindrical structure to resist blast, dynamical calculations are made, and compared with the test results.展开更多
The seismic design and analysis of nuclear power plant (NPP) begin with the seismic hazard assessment and design ground motion development for the site. The following steps are needed for the seismic hazard assessment...The seismic design and analysis of nuclear power plant (NPP) begin with the seismic hazard assessment and design ground motion development for the site. The following steps are needed for the seismic hazard assessment and design ground motion development:a. the development of regional seismo-tectonic model with seismic source areas within 500 km radius centered to the site;b. the development of strong motion prediction equations; c. logic three development for taking into account uncertainties and seismic hazard quantification;d. the development of uniform hazard response spectra for ground motion at the site;e. simulation of acceleration time histories compatible with uniform hazard response spectra. The following phase two in seismic design of NPP structures is the analysis of structural response for the design ground motion. This second phase of the process consists of the following steps:a. development of structural models of the plant buildings;b. development of the soil model underneath the plant buildings for soilstructure interaction response analysis;c. determination of instructure response spectra for the plant buildings for the equipment response analysis. In the third phase of the seismic design and analysis the equipment is analyzed on the basis of in-structure response spectra. For this purpose the structural models of the mechanical components and piping in the plant are set up. In large 3D-structural models used today the heaviest equipment of the primary coolant circuit is included in the structural model of the reactor building. In the fourth phase the electrical equipment and automation and control equipment are seismically qualified with the aid of the in-structure spectra developed in the phase two using large three-axial shaking tables. For this purpose the smoothed envelope spectra for calculated in-structure spectra are constructed and acceleration time is fitted to these smoothed envelope spectra.展开更多
During the life of an offshore structure, its structural strength declines due to various kinds of damages related to the time factor. In this paper, four major kinds of damages, including damages caused by fatigue, d...During the life of an offshore structure, its structural strength declines due to various kinds of damages related to the time factor. In this paper, four major kinds of damages, including damages caused by fatigue, dent, corrosion and marine life, are discussed. Based on these analyses, formulas for the evaluation of the damaged structure reliability are derived. Furthermore the computer program ISM for the analysis of structural reliability is developed by the use of Advanced First Order Second Moment method and Monte-Carlo Importance Sampling method. The reliability of a turbular joint and a beam are studied as numerical examples. The results show that the theory and the analysis method given in this paper are reasonable and effective.展开更多
This paper presents a set of fundamental equations for reliability analysis of single-critical-point aircraft structures.The mathematical model is formulated by considering the following factors:the static strength of...This paper presents a set of fundamental equations for reliability analysis of single-critical-point aircraft structures.The mathematical model is formulated by considering the following factors:the static strength of structure,initial crack,the initiation and propagation and unstability of fatigue crack,the residual strength of structure,the statistical distribution of load,the periods of overhaul,accident damage,the communication of damage among fleets etc.Based on this mathematical model,the influence of these factors on the reliability can be quantitatively analyzed,and various criteria for fatigue design of aircraft structures can be evaluated from the aspect of reliability.展开更多
Structural analysis problems can be formulized as either root finding problems,or optimization problems.The general practice is to choose the first option directly or to convert the second option again to a root findi...Structural analysis problems can be formulized as either root finding problems,or optimization problems.The general practice is to choose the first option directly or to convert the second option again to a root finding problem by taking relevant derivatives and equating them to zero.The second alternative is used very randomly as it is and only for some simple demonstrative problems,most probably due to difficulty in solving optimization problems by classical methods.The method called TPO/MA(Total Potential Optimization using Metaheuristic Algorithms)described in this study successfully enables to handle structural problems with optimization formulation.Using metaheuristic algorithms provides additional advantages in dealing with all kinds of constraints.展开更多
Analysis method for the dynamic behavior of viscoelastically damped structures is studied.A finite element model of sandwich beams with eight degrees of freedom is set up and the finite element formulation of the equa...Analysis method for the dynamic behavior of viscoelastically damped structures is studied.A finite element model of sandwich beams with eight degrees of freedom is set up and the finite element formulation of the equations of motion is given for the viscoelastically damped structures.An iteration method for solving nonlinear eigenvalue problems is suggested to analyze the dynamic behavior of viscoelastically damped structures. The method has been applied to the complex model analysis of a sandwich cantilever beam with viscoelastic damping material core.展开更多
In architecture,interlace structural concept is considered as a new design approach for cosmopolitan cities with high density to minimize the land use and increase the interaction.With various architectural approach,l...In architecture,interlace structural concept is considered as a new design approach for cosmopolitan cities with high density to minimize the land use and increase the interaction.With various architectural approach,land resources can be minimized by this interlace concept for residential complexes.Such buildings will eliminate the reduction of land resource problem and on the other side safety measures in structural design is incorporated by interlace concept of buildings.This new concept can be constructed steel or reinforced concrete.In this paper,an analytical approach has been presented for these buildings in architecture and structural design.In the research,design considerations were taken for interlaced structures with reinforced concrete and steel.Components of steel structure,isolated footing,and columns.This paper is presenting a step wise process for interlaced structures.They are identification of project area,layout and model preparation,analysis and design of concrete interlaced structure,analysis and design of steel interlaced structure,drafting of the plans and costing and estimation of the structures.Comparison of both reinforced concrete and steel structures were carried out.The main aim of the paper is to provide a comparison between steel and concrete interlaced structure.A cost estimation was carried out to determine optimum design and construction for interlaced structures.展开更多
In this paper, a kind of rationalism theory of shell is established which is of different mechanic characters in tension and in compression, and the finite element numerical analysis method is also described.
It is of great practical importance to analyze the shakedown of shell structures under cyclic loading, especially of those made of strain hardening materials.In this paper, same further understanding of the shakedown ...It is of great practical importance to analyze the shakedown of shell structures under cyclic loading, especially of those made of strain hardening materials.In this paper, same further understanding of the shakedown theorem for kinematic hardening materials has been made, and it is applied to analyze the shakedown of shell structures Though the residual stress of a real stale is related to plastic strain, the time-independent residual stress field as we will show in the theorem may be unrelated to the time-independent kinematically admissible plastic strain field For the engineering application, it will lie much more convenient to point this out clearly and definitely, otherwise it will be very difficult. Also, we have proposed a new method of proving this theorem.The above theorem is applied to the shakedown analysis of a cylindrical shell with hemispherical ends. According to the elastic solution, various possible residual sfcss and plastic strain Jlelds, the shakedown analysis of the structure can be reduced to a mathematical programming problem.The results of calculation show that the shakedown load oj strain hardening materials is about 30-40% higher than that of ideal plastic materials. So it is very important to consider the hardening of materials in the shakedown analysis,for it can greatly increase the structure design capacity, and meanwhile provide ascicntific basis to improve the design of shell structures.展开更多
The central solenoid is an important part of the HT-7U device. In this paper， the computational analysis of the stress and the displacement on the pre-load structures of the central solenoid have been made by the fin...The central solenoid is an important part of the HT-7U device. In this paper， the computational analysis of the stress and the displacement on the pre-load structures of the central solenoid have been made by the finite element analysis system COSMOS/M2.0 under room and/or operating temperature. According to the analytical results, the clip aprons and compression plates are all satisfied with safety design criteria.展开更多
Infrared(IR)spectroscopy,a technique within the realm of molecular vibrational spectroscopy,furnishes distinctive chemical signatures pivotal for both structural analysis and compound identification.A notable challeng...Infrared(IR)spectroscopy,a technique within the realm of molecular vibrational spectroscopy,furnishes distinctive chemical signatures pivotal for both structural analysis and compound identification.A notable challenge emerges from the misalignment between the mid-IR light wavelength range and molecular dimensions,culminating in a constrained absorption cross-section and diminished vibrational absorption coefficients(Supplementary data).展开更多
In the structural reliability analysis,the first-order reliability method(FORM)often yields significant errors when addressing nonlinear problems.Although the second-order reliability method(SORM)can provide higher ac...In the structural reliability analysis,the first-order reliability method(FORM)often yields significant errors when addressing nonlinear problems.Although the second-order reliability method(SORM)can provide higher accuracy,the additional computation of the Hessian matrix leads to lower computational efficiency.Additionally,when the dimensionality of the random variables is high,the approximation formula of SORM can result in larger errors.To address these issues,a structural reliability analysis method based on Kriging and spherical cap area integral is proposed.Firstly,this method integrates FORM with the quasi-Newton algorithm Broyden-Fletcher-Goldfarb-Shanno(BFGS),trains the Kriging model by using sample points from the algorithm’s iteration process,and combines the Kriging model with gradient information to approximate the Hessian matrix.Then,the failure surface is approximated as a rotating paraboloid,utilizing the spherical cap to replace the complex surface.For the n-dimensional case,the hyperspherical cap area expression is combined with the integral method to calculate the failure probability.Finally,the method is validated through three examples,demonstrating improved computational accuracy and efficiency compared to traditional methods.展开更多
[Objective] The study was to analyze the structure and function of HpaGXoo and the relationship between the two.[Method] Some related bioinformatics analysis software on internet such as NPSA,Swiss-Model,SAPS and Inte...[Objective] The study was to analyze the structure and function of HpaGXoo and the relationship between the two.[Method] Some related bioinformatics analysis software on internet such as NPSA,Swiss-Model,SAPS and InterPro Scan were adopted to analyze the structure and predict its function.[Result] HpaGXoo consists of 139 amino acids,and has many alpha-helical and coiled structure,no signal peptide on N-terminal and no transmembrane structure.It locates in bacterial cytoplasm.[Conclusion] The study will lay ...展开更多
A detailed understanding of seismicity originating from the Nanga Parbat syntaxis in the northwestern Himalaya is crucial for characterizing the active fault systems and associated neotectonic processes in the region....A detailed understanding of seismicity originating from the Nanga Parbat syntaxis in the northwestern Himalaya is crucial for characterizing the active fault systems and associated neotectonic processes in the region.Continuous earthquake monitoring through local seismic stations enables high-precision results by constraining the velocity structure.In this study,seismogram data from 244 small-magnitude earthquakes are analyzed to delineate the crustal thickness and investigate the source mechanisms beneath the Nanga Parbat syntaxis.The results are achieved with the application of Coupled Hypocenter Velocity Inversion(CHVI)analysis and Time Domain Moment Tensor(TDMT)analysis.The velocity inversion suggests that the Moho discontinuity lies at 60 km depth with an average vP/vS ratio of 1.735±0.017.The minimum 1D velocity model obtained through velocity inversion with least RMS error is further utilized in determining the source mechanism solution.In contrast to earlier studies,which highlighted strike-slip displacement accompanied by reverse dip-slip components,the present research provides a revised interpretation.The moment tensor analysis conducted in this study provides evidence of transtensional deformation associated with neotectonics,attributed to the presence of multiple shear zones.The results of the source mechanism for the selected earthquakes unveiled that the oblique-slip deformation is significantly controlled by the shear stresses coupled with the normal component of dip-slip movement.This is further supported by the higher values of the doublecouple moment tensor(85%),which indicate shear deformation,while the positive value of the compensated linear vector dipole(15%)confirms the presence of a normal component.The coexistence of transpressive and transtensive stresses,together with shallow hypocentral depths and high-amplitude tangential waveforms,can potentially cause devastating impacts in the surroundings of the Nanga Parbat syntaxis.展开更多
O3-types layered cathode materials in sodium-ion batteries(SIBs)suffer from the obvious lattice distortion induced by the complex phase transitions during Na^(+)intercalation/deintercalation process,leading to severe ...O3-types layered cathode materials in sodium-ion batteries(SIBs)suffer from the obvious lattice distortion induced by the complex phase transitions during Na^(+)intercalation/deintercalation process,leading to severe structural collapse and performance degradation.Herein,a series of high valence tantalum(Ta^(5+))doped Na(Ni_(0.4)Fe_(0.2)Mn_(0.4))_(1−x)Ta_(x)O_(2)(x=0/0.0025/0.005/0.01)secondary spherical particles are firstly developed,where Ta^(5+)doping enables the refined primary grain with a tightly stacked rod-like morphology.Comprehensive structural analysis via Neutron powder diffraction(NPD)and Synchrotron radiation X-ray diffraction(SXRD)reveals an expanded NaO_(2)slab and a reduction in Na site vacancy.The potential charge compensation mechanism is further illustrated by X-ray absorption spectroscopy(XAS)and X-ray photoelectron spectroscopy(XPS),unveiling a partial reduction from Ni^(3+)to Ni^(2+)with Ta^(5+)doping.In situ X-ray diffraction(in situ XRD)suggests that the decorated sample undergoes a volume change as low as 0.8%,in contrast with the pristine one(1.5%).Thus,the optimized sample with x=0.005 retains an enhanced capacity retention up to 70.4%at 1 C after 300 cycles in half-cell and delivers a high energy density of 251 Wh kg^(-1)(0.1 C)and with a good capacity retention of 81.0%at 1 C after 200 cycles in full-cell.Our findings provide new insights into the mechanism of high valence Ta^(5+)doping in stabilizing layered oxides cathode materials for SIBs.展开更多
基金Supported by the National Key R&D Program(2022YFF1300500)the Spring Goose Support Program(CYQN24018)the National Natural Science Foundation of China(32572123)。
文摘Dianthus spiculifolius Schur,as an emerging ornamental plant,has extensive applications and economic values.In this study,the DsCBL4 gene was successfully cloned,and its tissue-specific expression,expression patterns under various abiotic stresses,subcellular localization,and bioinformatics analysis of the encoded amino acid sequence were conducted.The results showed that the coding region of the DsCBL4 gene was 675 bp long,encoding 224 amino acids.It had high homology with the amino acids encoded by Amaranthus tricolor,Chenopodium quinoa and Spinacia oleracea.The predicted relative molecular mass of DsCBL4 was 25.61 ku,with an isoelectric point of 4.58,and it had phosphorylation sites,belonging to an unstable hydrophilic protein.Its secondary structure includedα-helices,irregular coils and extended chains.The tertiary structure prediction revealed that DsCBL4 had four EFhand calcium-binding domains necessary for Ca2+binding in plant calmodulin-like proteins and the FPSF motif for calcineurin B-like protein(CBL)-interacting protein kinase(CIPK)activation.The expression level of the DsCBL4 gene showed tissue specificity,with the highest expression in roots.It was induced by drought,low temperature,combined drought and low temperature,salt stress,nitrogen stress,phosphorus stress,calcium ion stress,high temperature stress,and abscisic acid(ABA)stress.Both transient infection in Nicotiana tabacum L.and stable expression in transgenic Arabidopsis thaliana showed that the DsCBL4 protein was localized to the cell membrane.These results suggested that DsCBL4 might be involved in the abiotic stress response of Dianthus spiculifolius through the calcium signaling pathway,providing a theoretical basis for understanding its molecular mechanism.This study provided an important reference for further exploring the role of the DsCBLs gene family in plant stress resistance.
文摘Neurodegenerative disorders,including Alzheimer’s disease(AD),Parkinson’s disease(PD),and amyotrophic lateral sclerosis,impose a considerable social and economic burden on society and have dramatic consequences for individuals and their families.The majority of existing interventions have been found to be capable of only a slight modification of disease progression or to moderately delay significant functional decline in motor,cognitive,or mental domains.
基金National Natural Science Foundation of China under Grant No.51078032the Visiting Scholar Foundation of China Scholarship Councilthe Center for Infrastructure Engineering Studies at Missouri University of Science and Technology
文摘An optimization method for the consistent evaluation of two Rayleigh damping coefficients is proposed. By minimizing an objective function such as an error term of the peak displacement of a structure, the two coefficients can be determined with response spectral analysis. The optimization method degenerates into the conventional method used in current practices when only two modes of vibration are included in the objective function. Therefore, the proposed method with all significant modes included for simplicity in practical applications results in suboptimal damping coefficients. The effects of both spatial distribution and frequency content of excitations as well as structural dynamic characteristics on the evaluation of Rayleigh damping coefficients were investigated with a five-story building structure. Two application examples with a 62-story high-rise building and a 840 m long cable-stayed bridge under ten earthquake excitations demonstrated the accuracy and effectiveness of the proposed method to account for all of the above effects.
文摘In the tubular frames with simple joints, the joints may show considerable local flexibility, which causes excessive deformation and affects internal force distributions. It is useful and important to study turbular joint flexibility as well as the effect of joint local flexibility on the global behavior of tubular structure for the design and building of offshore platforms. A new method for computing the stiffness coefficients of simple tubular joints is developed in this paper based on two previous computing models. According to this method, the local flexibility of T, Y, TY tubular joints are computed. This method has merits of clear physical sense, simplicity of computations and less c.p.u. time. The effect of flexibility of tubular joints on the global behavior of framed tubular structures is investigated by comparing the computed results of tubular structures with flexible tubular joints with those with rigid connections. The comparison shows that the consideration of local flexibility of tubular joints and its effect on the stress analysis of offshore structures has its practical significance.
基金Projects(51405516,U1334208)supported by the National Natural Science Foundation of ChinaProject(2013GK2001)supported by the Science and Technology Program for Hunan Provincial Science and Technology Department,ChinaProject(2013zzts040)supported by the Graduate Degree Thesis Innovation Foundation of Central South University,China
文摘For the safety protection of passengers when train crashes occur, special structures are crucially needed as a kind of indispensable energy absorbing device. With the help of the structures, crash kinetic-energy can be completely absorbed or dissipated for the aim of safety. Two composite structures(circumscribed circle structure and inscribed circle structure) were constructed. In addition, comparison and optimization of the crashworthy characteristic of the two structures were carried out based on the method of explicit finite element analysis(FEA) and Kriging surrogate model. According to the result of Kriging surrogate model, conclusions can be safely drawn that the specific energy absorption(SEA) and ratio of specific energy absorption to initial peak force(REAF) of circumscribed circle structure are lager than those of inscribed circle structure under the same design parameters. In other words, circumscribed circle structure has better performances with higher energy-absorbing ability and lower initial peak force. Besides, error analysis was adopted and the result of which indicates that the Kriging surrogate model has high nonlinear fitting precision. What is more, the SEA and REAF optimum values of the two structures have been obtained through analysis, and the crushing results have been illustrated when the two structures reach optimum SEA and REAF.
文摘In this paper, the generalized variational principle of dynamic analysis for the blast-resistant underground structures is established, and the corresponding generalized functional of elastoplastic analysis for underground structures is derived, and the generalized variational principle of nonconservative system is given, thus the fundamental of dynamical analysis for underground structures to resist blast is proposed. Finally, for the underground cylindrical structure to resist blast, dynamical calculations are made, and compared with the test results.
文摘The seismic design and analysis of nuclear power plant (NPP) begin with the seismic hazard assessment and design ground motion development for the site. The following steps are needed for the seismic hazard assessment and design ground motion development:a. the development of regional seismo-tectonic model with seismic source areas within 500 km radius centered to the site;b. the development of strong motion prediction equations; c. logic three development for taking into account uncertainties and seismic hazard quantification;d. the development of uniform hazard response spectra for ground motion at the site;e. simulation of acceleration time histories compatible with uniform hazard response spectra. The following phase two in seismic design of NPP structures is the analysis of structural response for the design ground motion. This second phase of the process consists of the following steps:a. development of structural models of the plant buildings;b. development of the soil model underneath the plant buildings for soilstructure interaction response analysis;c. determination of instructure response spectra for the plant buildings for the equipment response analysis. In the third phase of the seismic design and analysis the equipment is analyzed on the basis of in-structure response spectra. For this purpose the structural models of the mechanical components and piping in the plant are set up. In large 3D-structural models used today the heaviest equipment of the primary coolant circuit is included in the structural model of the reactor building. In the fourth phase the electrical equipment and automation and control equipment are seismically qualified with the aid of the in-structure spectra developed in the phase two using large three-axial shaking tables. For this purpose the smoothed envelope spectra for calculated in-structure spectra are constructed and acceleration time is fitted to these smoothed envelope spectra.
文摘During the life of an offshore structure, its structural strength declines due to various kinds of damages related to the time factor. In this paper, four major kinds of damages, including damages caused by fatigue, dent, corrosion and marine life, are discussed. Based on these analyses, formulas for the evaluation of the damaged structure reliability are derived. Furthermore the computer program ISM for the analysis of structural reliability is developed by the use of Advanced First Order Second Moment method and Monte-Carlo Importance Sampling method. The reliability of a turbular joint and a beam are studied as numerical examples. The results show that the theory and the analysis method given in this paper are reasonable and effective.
文摘This paper presents a set of fundamental equations for reliability analysis of single-critical-point aircraft structures.The mathematical model is formulated by considering the following factors:the static strength of structure,initial crack,the initiation and propagation and unstability of fatigue crack,the residual strength of structure,the statistical distribution of load,the periods of overhaul,accident damage,the communication of damage among fleets etc.Based on this mathematical model,the influence of these factors on the reliability can be quantitatively analyzed,and various criteria for fatigue design of aircraft structures can be evaluated from the aspect of reliability.
文摘Structural analysis problems can be formulized as either root finding problems,or optimization problems.The general practice is to choose the first option directly or to convert the second option again to a root finding problem by taking relevant derivatives and equating them to zero.The second alternative is used very randomly as it is and only for some simple demonstrative problems,most probably due to difficulty in solving optimization problems by classical methods.The method called TPO/MA(Total Potential Optimization using Metaheuristic Algorithms)described in this study successfully enables to handle structural problems with optimization formulation.Using metaheuristic algorithms provides additional advantages in dealing with all kinds of constraints.
文摘Analysis method for the dynamic behavior of viscoelastically damped structures is studied.A finite element model of sandwich beams with eight degrees of freedom is set up and the finite element formulation of the equations of motion is given for the viscoelastically damped structures.An iteration method for solving nonlinear eigenvalue problems is suggested to analyze the dynamic behavior of viscoelastically damped structures. The method has been applied to the complex model analysis of a sandwich cantilever beam with viscoelastic damping material core.
文摘In architecture,interlace structural concept is considered as a new design approach for cosmopolitan cities with high density to minimize the land use and increase the interaction.With various architectural approach,land resources can be minimized by this interlace concept for residential complexes.Such buildings will eliminate the reduction of land resource problem and on the other side safety measures in structural design is incorporated by interlace concept of buildings.This new concept can be constructed steel or reinforced concrete.In this paper,an analytical approach has been presented for these buildings in architecture and structural design.In the research,design considerations were taken for interlaced structures with reinforced concrete and steel.Components of steel structure,isolated footing,and columns.This paper is presenting a step wise process for interlaced structures.They are identification of project area,layout and model preparation,analysis and design of concrete interlaced structure,analysis and design of steel interlaced structure,drafting of the plans and costing and estimation of the structures.Comparison of both reinforced concrete and steel structures were carried out.The main aim of the paper is to provide a comparison between steel and concrete interlaced structure.A cost estimation was carried out to determine optimum design and construction for interlaced structures.
文摘In this paper, a kind of rationalism theory of shell is established which is of different mechanic characters in tension and in compression, and the finite element numerical analysis method is also described.
文摘It is of great practical importance to analyze the shakedown of shell structures under cyclic loading, especially of those made of strain hardening materials.In this paper, same further understanding of the shakedown theorem for kinematic hardening materials has been made, and it is applied to analyze the shakedown of shell structures Though the residual stress of a real stale is related to plastic strain, the time-independent residual stress field as we will show in the theorem may be unrelated to the time-independent kinematically admissible plastic strain field For the engineering application, it will lie much more convenient to point this out clearly and definitely, otherwise it will be very difficult. Also, we have proposed a new method of proving this theorem.The above theorem is applied to the shakedown analysis of a cylindrical shell with hemispherical ends. According to the elastic solution, various possible residual sfcss and plastic strain Jlelds, the shakedown analysis of the structure can be reduced to a mathematical programming problem.The results of calculation show that the shakedown load oj strain hardening materials is about 30-40% higher than that of ideal plastic materials. So it is very important to consider the hardening of materials in the shakedown analysis,for it can greatly increase the structure design capacity, and meanwhile provide ascicntific basis to improve the design of shell structures.
文摘The central solenoid is an important part of the HT-7U device. In this paper， the computational analysis of the stress and the displacement on the pre-load structures of the central solenoid have been made by the finite element analysis system COSMOS/M2.0 under room and/or operating temperature. According to the analytical results, the clip aprons and compression plates are all satisfied with safety design criteria.
基金supported by National Natural Science Foundation of China(Grant No.:32301161)the Natural Scientific Foundation of Hunan Province,China(Grant No.:2023JJ60052)+3 种基金the Scientific Research Project of Hunan Provincial Health Commission,China(Grant No.:202112062218,20190161)the Scientific Research Project of Hunan Provincial Department of Education,China(Grant No.:22B0455)the Clinical“4310”Project of the University of South China,China(Grant No.:20224310NHYCG02)the Doctoral Scientific Research Foundation of University of South China,China(Grant No.:200XQD042).
文摘Infrared(IR)spectroscopy,a technique within the realm of molecular vibrational spectroscopy,furnishes distinctive chemical signatures pivotal for both structural analysis and compound identification.A notable challenge emerges from the misalignment between the mid-IR light wavelength range and molecular dimensions,culminating in a constrained absorption cross-section and diminished vibrational absorption coefficients(Supplementary data).
基金National Natural Science Foundation of China(No.52375236)Fundamental Research Funds for the Central Universities,China(No.23D110316)。
文摘In the structural reliability analysis,the first-order reliability method(FORM)often yields significant errors when addressing nonlinear problems.Although the second-order reliability method(SORM)can provide higher accuracy,the additional computation of the Hessian matrix leads to lower computational efficiency.Additionally,when the dimensionality of the random variables is high,the approximation formula of SORM can result in larger errors.To address these issues,a structural reliability analysis method based on Kriging and spherical cap area integral is proposed.Firstly,this method integrates FORM with the quasi-Newton algorithm Broyden-Fletcher-Goldfarb-Shanno(BFGS),trains the Kriging model by using sample points from the algorithm’s iteration process,and combines the Kriging model with gradient information to approximate the Hessian matrix.Then,the failure surface is approximated as a rotating paraboloid,utilizing the spherical cap to replace the complex surface.For the n-dimensional case,the hyperspherical cap area expression is combined with the integral method to calculate the failure probability.Finally,the method is validated through three examples,demonstrating improved computational accuracy and efficiency compared to traditional methods.
基金Supported by Langfang Teachers College Research Grant(LSZB200803)~~
文摘[Objective] The study was to analyze the structure and function of HpaGXoo and the relationship between the two.[Method] Some related bioinformatics analysis software on internet such as NPSA,Swiss-Model,SAPS and InterPro Scan were adopted to analyze the structure and predict its function.[Result] HpaGXoo consists of 139 amino acids,and has many alpha-helical and coiled structure,no signal peptide on N-terminal and no transmembrane structure.It locates in bacterial cytoplasm.[Conclusion] The study will lay ...
文摘A detailed understanding of seismicity originating from the Nanga Parbat syntaxis in the northwestern Himalaya is crucial for characterizing the active fault systems and associated neotectonic processes in the region.Continuous earthquake monitoring through local seismic stations enables high-precision results by constraining the velocity structure.In this study,seismogram data from 244 small-magnitude earthquakes are analyzed to delineate the crustal thickness and investigate the source mechanisms beneath the Nanga Parbat syntaxis.The results are achieved with the application of Coupled Hypocenter Velocity Inversion(CHVI)analysis and Time Domain Moment Tensor(TDMT)analysis.The velocity inversion suggests that the Moho discontinuity lies at 60 km depth with an average vP/vS ratio of 1.735±0.017.The minimum 1D velocity model obtained through velocity inversion with least RMS error is further utilized in determining the source mechanism solution.In contrast to earlier studies,which highlighted strike-slip displacement accompanied by reverse dip-slip components,the present research provides a revised interpretation.The moment tensor analysis conducted in this study provides evidence of transtensional deformation associated with neotectonics,attributed to the presence of multiple shear zones.The results of the source mechanism for the selected earthquakes unveiled that the oblique-slip deformation is significantly controlled by the shear stresses coupled with the normal component of dip-slip movement.This is further supported by the higher values of the doublecouple moment tensor(85%),which indicate shear deformation,while the positive value of the compensated linear vector dipole(15%)confirms the presence of a normal component.The coexistence of transpressive and transtensive stresses,together with shallow hypocentral depths and high-amplitude tangential waveforms,can potentially cause devastating impacts in the surroundings of the Nanga Parbat syntaxis.
基金supported by the National Natural Science Foundation of China (52402298, 52172224, 52202228, 22479112)the Science and Technology Correspondent Project of Tianjin(24YDTPJC00240)+3 种基金Science Research Project of Hebei Education Department (BJK2022011)Central Funds Guiding the Local Science and Technology Development of Hebei Province (236Z4404G)the Beijing Tianjin Hebei Basic Research Cooperation Special Project(E2024202273)Tianjin Sci.&Tech. Program (22YFYSHZ00220)
文摘O3-types layered cathode materials in sodium-ion batteries(SIBs)suffer from the obvious lattice distortion induced by the complex phase transitions during Na^(+)intercalation/deintercalation process,leading to severe structural collapse and performance degradation.Herein,a series of high valence tantalum(Ta^(5+))doped Na(Ni_(0.4)Fe_(0.2)Mn_(0.4))_(1−x)Ta_(x)O_(2)(x=0/0.0025/0.005/0.01)secondary spherical particles are firstly developed,where Ta^(5+)doping enables the refined primary grain with a tightly stacked rod-like morphology.Comprehensive structural analysis via Neutron powder diffraction(NPD)and Synchrotron radiation X-ray diffraction(SXRD)reveals an expanded NaO_(2)slab and a reduction in Na site vacancy.The potential charge compensation mechanism is further illustrated by X-ray absorption spectroscopy(XAS)and X-ray photoelectron spectroscopy(XPS),unveiling a partial reduction from Ni^(3+)to Ni^(2+)with Ta^(5+)doping.In situ X-ray diffraction(in situ XRD)suggests that the decorated sample undergoes a volume change as low as 0.8%,in contrast with the pristine one(1.5%).Thus,the optimized sample with x=0.005 retains an enhanced capacity retention up to 70.4%at 1 C after 300 cycles in half-cell and delivers a high energy density of 251 Wh kg^(-1)(0.1 C)and with a good capacity retention of 81.0%at 1 C after 200 cycles in full-cell.Our findings provide new insights into the mechanism of high valence Ta^(5+)doping in stabilizing layered oxides cathode materials for SIBs.
