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Effect of 2s Orbitals on the Electronic Hopping in Polyacetylene

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Chinese Physics Letters 1997年第1期14卷 59-62页

作者： tong guo-ping Department of Physics Zhejiang Normal UniversityJinhua 321004

The extended Wannier function constructed by hydrogen-like atom wave function is used to calculate the electronic hopping and the density of the states of trans-polyacetylene with a single-chain planar *** this technique 2s and 2pz orbitals are taken into *** computed result shows that the electronic hopping interactions,especially non-neighbor hopping,are considerably affected by 2s orbitals,which are able not only to narrow the energy bandwidth and the gap but also to weaken the nearest neighbor hopping slightly and to enhance the non-neighbor hopping greatly.

关键词： structure. neighbor narrow

Seismic resilient shear wall structures:A state-of-the-art review

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Science China(Technological Sciences) 2023年第6期66卷 1640-1661页

作者： XU Gang guo tong LI AiQun Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education Southeast UniversityNanjing 211189China Multi-Functional Shaking Tables Laboratory Beijing University of Civil Engineering and ArchitectureBeijing 100044China

The ductile design principle has been widely adopted in seismic design of structures,so the main structural components are designed to have the dual functions of bearing and energy dissipation under the *** recent years,the intensity of major earthquakes occurred in China,Chile,New Zealand,and Japan had reached or exceeded the design level of the maximum credible *** most cases,the designed structures did not collapse and the casualties were ***,many structures were seriously damaged and must be overhauled or rebuilt,resulting in huge economic ***,researchers have paid more attention to the seismic resilient *** shear wall can provide an efficient lateral force resisting capacity and has a wide range of applications in building *** review firstly summarized the research advances of seismic resilient shear wall structures,mainly from three aspects:high-performance materials,replaceable components,and hybrid structural systems;then,the development of seismic performance analysis,design methods,and engineering applications of seismic resilient shear wall structures were presented;finally,the key issues that need to be explored in the future research were discussed,which was helpful for the wide application of seismic resilient shear wall structures.

关键词： seismic resilience shear wall self-centering structure seismic design engineering application

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Analytical and experimental study on mild steel dampers with non-uniform vertical slits

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Earthquake Engineering and Engineering Vibration 2015年第1期14卷 111-123页

作者： Zheng Jie Li Aiqun guo tong School of Civil Engineering Southeast University Key Laboratory of Concrete and Prestressed Concrete Structure of China Ministry of Education Southeast University

This study proposes a novel mild steel damper with non-uniform vertical slits. The influence of different shapes of vertical slits of the core energy plate on the energy dissipation and buckling resistance capacities is analyzed. Based on the theoretical analysis, formulas of key parameters of the dampers, including the elastic lateral stiffness, shear bearing capacity and yield displacement, are derived. The effectiveness of the proposed damper is demonstrated through pseudo static tests on four 0.25-scale specimens. Performance of these dampers, i.e. cyclic deformation, stress distribution, energy dissipation capacity, etc., are presented and discussed. Using the numerical models of dampers calibrated through test data, earthquake time-history analyses were conducted, and it is observed that the dampers significantly reduce the seismic responses of the prototype frame and have a desirable energy dissipation capacity.

关键词： mild steel damper vertical slit pseudo static test energy dissipation

Comparison of delay compensation methods for real-time hybrid simulation using frequency-domain evaluation index

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Earthquake Engineering and Engineering Vibration 2016年第1期15卷 129-143页

作者： Xu Weijie guo tong Chen Cheng School of Civil Engineering Southeast University Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education Southeast University School of Engineering San Francisco State University

The delay compensation method plays an essential role in maintaining the stability and achieving accurate real-time hybrid simulation results. The effectiveness of various compensation methods in different test scenarios, however, needs to be quantitatively evaluated. In this study, four compensation methods （i.e., the polynomial extrapolation, the linear acceleration extrapolation, the inverse compensation and the adaptive inverse compensation） are selected and compared experimentally using a frequency evaluation index （FEI） method. The effectiveness of the FEI method is first verified through comparison with the discrete transfer fimction approach for compensation methods assuming constant delay. Incomparable advantage is further demonstrated for the FEI method when applied to adaptive compensation methods, where the discrete transfer function approach is difficult to implement. Both numerical simulation and laboratory tests with predefined displacements are conducted using sinusoidal signals and random signals as inputs. Findings from numerical simulation and experimental results demonstrate that the FEI method is an efficient and effective approach to compare the performance of different compensation methods, especially for those requiring adaptation of compensation parameters.

关键词： real-time hybrid simulation frequency domain evaluation index delay compensation methods

Numerical simulation of the seismic behavior of self-centering steel beam-column connections with bottom flange friction devices

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Earthquake Engineering and Engineering Vibration 2011年第2期10卷 229-238页

作者： guo tong Song Lianglong Zhang guodong Key Laboratory of Concrete and Prestressed Concrete Structure Ministry of Education Southeast Univ. Nanjing 210096 China

A new type of steel moment resisting frame with bottom flange friction devices （BFFDs） has been developed to provide self-centering capacity and energy dissipation, and to reduce permanent deformations under earthquakes. This paper presents a numerical simulation of self-centering beam-column connections with BFFDs, in which the gap opening/closing at the beam-column interfaces is simulated by using pairs of zero-length elements with compression-only material properties, and the energy dissipation due to friction is simulated by using truss elements with specified hysteretic behavior. In particular, the effect of the friction bolt bearing against the slotted plate in the BFFDs was modeled, so that the increase in lateral force and the loss of friction force due to the bolt bearing could be taken into account. Parallel elastic-perfectly plastic gap （ElasticPPGap） materials in the Open System for Earthquake Engineering Simulation （OpenSees） were used with predefined gaps to specify the sequence that each bolt went into the bearing and the corresponding increase in bending stiffness. The MinMax material in OpenSees is used to specify the minimum and maximum values of strains of the ElasticPPGap materials. To consider the loss of friction force due to bok bearing, a number of parallel hysteretic materials were used, and the failure of these materials in sequence simulated the gradual loss of friction force. Analysis results obtained by using the proposed numerical model are discussed and compared with the test results under cyclic loadings and the seismic loading, respectively.

关键词： numerical simulation post tensioned self-centering moment resisting steel frame bottom flange frictiondevice bolt bearing

αB-crystallin malondialdehyde,superoxide dismutase, and lutathione peroxidase changes in X-ray irradiated rat lens

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International Journal of Ophthalmology(English edition) 2011年第4期4卷 365-370页

作者： guo-Xu Xu, guo-tong Xu Department of Ophthalmology the Second Hospital of Soochow University Suzhou 215004 Jiangsu Province China tongji Eye Institute and Department of Regenerative Medicine Tongji University School of Medicine Shanghai 200092 China

AIM: To evaluate αB-crystallin malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPx) changes in X-ray irradiated rat lens. METHODS: Eight-week-old Sprague-Dawley male rats received X-ray irradiation to the head with rest of the body protected. The exposure dose ranged from 2 to 25 Grays (Gy). The cataract status were examined by slit lamp and rated with 'four-grade systems' post-irradiation. The lens MDA level, and the activities of SOD and GPx were measured in a short-term experiment post-irradiation, and αB-crystallin protein levels were quantified. RESULTS: The lenses of normal control and the X-ray irradiated groups with the dose up to 10 Gy remained transparent throughout the experiment. The lens first appeared tiny scatters, and even lamellar opacities in the posterior capsule 45 days post-irradiation with the dose of 15 Gy, and progressed slowly to the advance stage of cataract; while, for the higher dose (25 Gy), the opacity of lens appeared much earlier, and progressed more rapidly to mature stage of cataract within 1 month. At the end of the observation (90 days post-irradiation), almost all lenses became complete opacity with the higher dose (25 Gy). The degree of lens opacity was rated accordingly. The lens MDA level was increased, and SOD and GPx activities were decreased with a dose-dependent manner post-irradiation. The αB-crystallin protein level was decreased dose-dependently at the end point of observation. CONCLUSION: Oxidative events and αB-crystallin may play important roles in the pathogenesis of cataract in X-ray irradiated rat lens.

关键词： αB-crystallin malondialdehyde superoxide dismutase glutathione peroxidase X-ray irradiation cataract

Exploration of instantaneous frequency for local control assessment in real-time hybrid simulation

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Earthquake Engineering and Engineering Vibration 2024年第4期23卷 995-1008页

作者： Xu Weijie Peng Changle guo tong Chen Cheng Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education Southeast UniversityNanjing 211189China School of Engineering San Francisco State UniversitySan Francisco 94132-1722USA

Local control parameters such as instantaneous delay and instantaneous amplitude play an essential role in evaluating the performance and maintaining the stability of real-time hybrid simulation(RTHS).However,existing methods have limitations in obtaining this local assessment in either the time domain or frequency *** this study,the instantaneous frequency is introduced to determine local control parameters for actuator tracking assessment in a real-time hybrid *** properties,including amplitude,delay,frequency and phase,are then calculated based on analytic signals translated from actuator tracking signals through the Hilbert *** issues are discussed and solutions are proposed for calculation of local control *** simulations are first conducted for sinusoidal and chirp signals with time varying amplitude error and delay to demonstrate the potential of the proposed *** tests also are conducted for a predefined random signal as well as the RTHS of a single degree of freedom structure with a self-centering viscous damper to experimentally verify the effectiveness of the proposed use of the instantaneous *** from the ensuing analysis clearly demonstrate that the instantaneous frequency provides great potential for local control assessment,and the proposed method enables local tracking parameters with good accuracy.

关键词： real-time hybrid simulation tracking assessment instantaneous frequency Hilbert transform

A force transfer mechanism for triggering landslides during rainfall infiltration

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Journal of Mountain Science 2018年第11期15卷 2480-2491页

作者： LIU Gang tong Fu-guo ZHAO Yi-tong TIAN Bin College of Hydraulic & Environment Engineering China Three Gorges University

Shallow slope failures induced by rainfall infiltration occur frequently, and the relevant triggering mechanisms have been widely ***-induced landslides are widely recognized to be caused by increases in soil weight, seepage force and pore water pressure or decreases in soil mechanical properties. However, even when all these factors are considered, some landslides still cannot be explained well. The increased pore water pressure in a slope reduces the effective stress of the soil and may trigger slope failure. Similarly, the pore gas pressure in a slope also reduces the effective stress of the soil but has been neglected in previous studies. As the viscosity of air is nearly negligible when compared with that of water, the pore gas pressure spreads faster, and its influence is wider, which is harmful for the stability of the slope. In this paper, the effects of pore gas pressure are considered in a shallow slope stability analysis, and a self-designed experiment is conducted to validate the force transfer *** simulation results show that the pore gas pressure in the slope increases sharply at different locations under heavy rainfall conditions and that the pore gas pressure causes a rapid decrease in the slope safety factor. Laboratory experimental results show that the pore gas pressure throughout the whole unsaturated zone has the same value, which indicates that the gas pressure could spread quickly to the whole sample.

关键词： Landslide Force transfer mechanism Rainfall infiltration Water-air two-phase flow

Analysis of actuator delay and its effect on uncertainty quantification for real-time hybrid simulation

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Earthquake Engineering and Engineering Vibration 2017年第4期16卷 713-725页

作者： Cheng Chen Weijie Xu tong guo Kai Chen School of Engineering San Francisco State University Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education Southeast University

Uncertainties in structure properties can result in different responses in hybrid simulations. Quantification of the effect of these tmcertainties would enable researchers to estimate the variances of structural responses observed from experiments. This poses challenges for real-time hybrid simulation （RTHS） due to the existence of actuator delay. Polynomial chaos expansion （PCE） projects the model outputs on a basis of orthogonal stochastic polynomials to account for influences of model uncertainties. In this paper, PCE is utilized to evaluate effect of actuator delay on the maximum displacement from real-time hybrid simulation of a single degree of freedom （SDOF） structure when accounting for uncertainties in structural properties. The PCE is first applied for RTHS without delay to determine the order of PCE, the number of sample points as well as the method for coefficients calculation. The PCE is then applied to RTHS with actuator delay. The mean, variance and Sobol indices are compared and discussed to evaluate the effects of actuator delay on uncertainty quantification for RTHS. Results show that the mean and the variance of the maximum displacement increase linearly and exponentially with respect to actuator delay, respectively. Sensitivity analysis through Sobol indices also indicates the influence of the single random variable decreases while the coupling effect increases with the increase of actuator delay.

关键词： real-time hybrid simulation actuator delay polynomial chaos expansion delay differential equation uncertainty quantification