检索结果-南通市图书馆

Silk-based nerve guidance conduits with macroscopic holes modulate the vascularization of regenerating rat sciatic nerve

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第6期20卷 1789-1800页

作者： carina Hromada Patrick Heimel Markus Kerbl LászlóGál Sylvia Nürnberger Barbara Schaedl James Ferguson Nicole Swiadek Xavier Monforte Johannes c.Heinzel Antal Nógrádi Andreas H.Teuschl-Woller David Hercher Department Life Science Engineering University of Applied Sciences Technikum WienViennaAustria Austrian cluster for Tissue Regeneration ViennaAustria Ludwig Boltzmann Institute for Traumatology The Research Center in Cooperation with AUVAViennaAustria University clinic of Dentistry Medical University of ViennaViennaAustria Department of Plastic Reconstructive and Aesthetic SurgeryLandesklinikum Wiener Neustadt2700 Wiener NeustadtAustria Department of Anatomy Histology and EmbryologyAlbert Szent-Györgyi Medical SchoolUniversity of SzegedSzegedHungary Medical University of Vienna Department of Orthopedics and Trauma SurgeryDevision of Trauma SurgeryViennaAustria Department of Hand- PlasticReconstructive and Burn SurgeryBG Unfallklinik TuebingenUniversity of TuebingenTuebingenGermany

Peripheral nerve injuries induce a severe motor and sensory deficit. Since the availability of autologous nerve transplants for nerve repair is very limited, alternative treatment strategies are sought, including the use of tubular nerve guidance conduits(tNGcs). However, the use of tNGcs results in poor functional recovery and central necrosis of the regenerating tissue, which limits their application to short nerve lesion defects(typically shorter than 3 cm). Given the importance of vascularization in nerve regeneration, we hypothesized that enabling the growth of blood vessels from the surrounding tissue into the regenerating nerve within the tNGc would help eliminate necrotic processes and lead to improved regeneration. In this study, we reported the application of macroscopic holes into the tubular walls of silk-based tNGcs and compared the various features of these improved silk^(+) tNGcs with the tubes without holes(silk^(–) tNGcs) and autologous nerve transplants in an 8-mm sciatic nerve defect in rats. Using a combination of micro-computed tomography and histological analyses, we were able to prove that the use of silk^(+) tNGcs induced the growth of blood vessels from the adjacent tissue to the intraluminal neovascular formation. A significantly higher number of blood vessels in the silk^(+) group was found compared with autologous nerve transplants and silk^(–), accompanied by improved axon regeneration at the distal coaptation point compared with the silk^(–) tNGcs at 7 weeks postoperatively. In the 15-mm(critical size) sciatic nerve defect model, we again observed a distinct ingrowth of blood vessels through the tubular walls of silk^(+) tNGcs, but without improved functional recovery at 12 weeks postoperatively. Our data proves that macroporous tNGcs increase the vascular supply of regenerating nerves and facilitate improved axonal regeneration in a short-defect model but not in a critical-size defect model. This study suggests that further optimizatio

关键词： axon regeneration blood vessel functional recovery macroporous nerve lesion peripheral nerve repair sciatic nerve silk-based nerve guidance conduit vascularization

Detection of Breaking Waves Using X-Band Pulse Radar in the Nearshore Region

在线全文

学校读者我要写书评

暂无评论

china Ocean Engineering 2013年第4期27卷 549-556页

作者： Y.c.Lin c.c.chang M.c.Lee H.c.chan J.M.Leu Department of Hydraulic and Ocean Engineering National Cheng-Kung University Department of Soil and Water conservation National Chung Hsing University Department of Hospitality Management Taiwan Shoufu University

An X-band pulsed Doppler microwave radar has been used to determine the characteristics of breaking waves. Field experiments were conducted at the Shuang-Si estuary in the north of Taiwan in the winter of 2005. Analyses on maxima radar cross section and Doppler frequency shift are done to characterize wave breaking zones. Based on observations of breaking waves, the wave breaking zones are shown to be located at water depths of 1.8 to 2.2 m in the experimental site. In general, the results indicate that a radar system has the potential to delineate the spatial variation of breaking waves clearly and that this is sufficient to achieve a measurement operation for near-shore air-sea interaction events.

关键词： radar Doppler effect wave breaking coastal zone

New method for rekindling the explosive waves in Maxwellian space plasmas

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2020年第12期22卷 48-58页

作者： G c DAS Kalikadas Road Byelane HazraparaCoochbehar-736101West BengalIndia

Our interest is to study the nonlinear wave phenomena in complex plasma constituents with Maxwellian electrons and ions. The main aim is to use a new method known as the(G′/G)method to exhibit the effects of dust charge fluctuations on the evolution of nonlinear waves. The coherent features of the shock and solitary waves along with the generation of high-energy waves have been amplified through the solution of the Korteweg–de Vries–Burgers equation,and the different natures of the waves were found successfully. Results are discussed graphically with the thoughtful choice of typical plasma parameters from different space plasma environments, exactly those found in cosmic dusty plasmas laden in ionospheric auroral region,radial spokes of Saturn's rings, planetary nebulae and solar F-corona region. All conclusions are in good accordance with the actual occurrences and could be of interest to further investigations of space. Moreover, the applicability of the present method is hoped to be a great enhancement by its use as ingenious mechanism used to evaluate the soliton dynamics and Burgers shock waves.

关键词： Maxwellian complex plasma nonlinear waves soliton and shock propagation (G′/G)method space plasmas

Pushover analysis of reinforced concrete frames considering shear failure at beam-column joints

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2013年第3期12卷 373-383页

作者： Y.c.Sung T.K.Lin c.c.Hsiao M.c.Lai Bridge Division Center for Research on Earthquake EngineeringTaipei University of Technology (NTUT) chiao Tung University Taipei University of Technology (NTUT)

Since most current seismic capacity evaluations of reinforced concrete （Rc） frame structures are implemented by either static pushover analysis （PA） or dynamic time history analysis, with diverse settings of the plastic hinges （PHs） on such main structural components as columns, beams and walls, the complex behavior of shear failure at beam-column joints （BcJs） during major earthquakes is commonly neglected. This study proposes new nonlinear PA procedures that consider shear failure at BcJs and seek to assess the actual damage to Rc structures. Based on the specifications of FEMA-356, a simplified joint model composed of two nonlinear cross struts placed diagonally over the location of the plastic hinge is established, allowing a sophisticated PA to be performed. To verify the validity of this method, the analytical results for the capacity curves and the failure mechanism derived from three different full-size Rc frames are compared with the experimental measurements. By considering shear failure at BcJs, the proposed nonlinear analytical procedures can be used to estimate the structural behavior of Rc frames, including seismic capacity and the progressive failure sequence of joints, in a precise and effective manner.

关键词： Rc frame beam-column joint pushover analysis capacity curve plastic hinge performance-based seismic evaluation

Roles of soil-structure interaction and damping in base-isolated structures built on numerous soil layers overlying a half-space

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2016年第2期15卷 387-400页

作者： c.S.Tsai c.I.Hsueh H.c.Su Department of civil Engineering Feng Chia University Graduate Institute of civil & Hydraulic Engineering Feng Chia University Department of Water Resources Engineering and conservation Feng Chia University

This study examines the roles of soil-structure interaction （SSI）, higher modes, and damping in a base-isolated structure built on multiple layers of soil overlying a half space. closed-form solutions for the entire system, including a superstructure, seismic isolator, and numerous soil layers overlying a half-space, were obtained. The formulations obtained in this study simply in terms of well-known frequencies and mechanical impedance ratios can explicitly interpret the dynamic behavior of a base-isolated structure interacting with multiple soil layers overlying a half-space. The key factors influencing the performance of the isolation system are the damping ratio of the isolator and the ratio of the natural frequency of the fixed-base structure to that of the isolated structure by assuming that the superstructure moves as a rigid body. This study reveals that higher damping in the base isolator is unfavorable to higher mode responses that usually dominate the responses of the superstructure and that the damping mechanism plays an important role in transmitting energy in addition to absorbing energy. It is also concluded that it is possible to design a soft soil layer as an isolation system for isolating vibration energy.

关键词： base isolation seismic isolation soil-structure interaction closed- form solution higher-mode effects soilstratum passive control damping effects

Equivalent series system to model a multiple friction pendulum system with numerous sliding interfaces for seismic analyses

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2014年第1期13卷 85-99页

作者： c.S.Tsai H.c.Su T.c.chiang Department of civil Engineering Feng Chia University Department of Water Resources Engineering and conservation Feng Chia University Earthquake Proof Systems Inc.

current structural analysis software programs offer few if any applicable device-specifi c hysteresis rules or nonlinear elements to simulate the precise mechanical behavior of a multiple friction pendulum system(MFPS) with numerous sliding *** on the concept of subsystems,an equivalent series system that adopts existing nonlinear elements with parameters systematically calculated and mathematically proven through rigorous derivations is *** aim is to simulate the characteristics of sliding motions for an MFPS isolation system with numerous concave sliding interfaces without prior knowledge of detailed information on the mobilized forces at various sliding *** MFPS with numerous concave sliding interfaces and one articulated or rigid slider located between these interfaces is divided into two subsystems: the fi rst represents the concave sliding interfaces above the slider,and the second represents those below the *** equivalent series system for the entire system is then obtained by connecting those for each subsystem in *** equivalent series system is validated by comparing numerical results for an MFPS with four sliding interfaces obtained from the proposed method with those from a previous study by Fenz and ***,these numerical results demonstrate that an MFPS isolator with numerous concave sliding interfaces,which may have any number of sliding interfaces,is a good isolation device to protect structures from earthquake damage through appropriate designs with controllable mechanisms.

关键词： seismic isolation base isolation earthquake engineering multiple friction pendulum system structural control mathematical modeling equivalent series system

Nonlinear dynamic analysis of multi-base seismically isolated structures with uplift potentialⅡ:verification examples

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2010年第1期9卷 83-91页

作者： Panayiotis c.Roussis Panos c.Tsopelas Michael c.constantinou Department of civil and Environmental Engineering University of Cyprus Department of civil Engineering University of Thessaly Department of civil Structural and Environmental EngineeringUniversity at BuffaloState University of New York

The work presented in this paper serves as numerical verification of the analytical model developed in the companion paper for nonlinear dynamic analysis of multi-base seismically isolated structures. To this end, two numerical examples have been analyzed using the computational algorithm incorporated into program 3D-BASIS-ME-MB, developed on the basis of the newly-formulated analytical model. The first example concerns a seven-story model structure that was tested on the earthquake simulator at the University at Buflhlo and was also used as a verification example for program SAP2000. The second example concerns a two-tower, multi-story structure with a split-level seismic-isolation system. For purposes of verification, key results produced by 3D-BASIS-ME-MB are compared to experimental results, or results obtained from other structural/finite element programs. In both examples, the analyzed structure is excited under conditions of bearing uplift, thus yielding a case of much interest in verifying the capabilities of the developed analysis tool.

关键词： seismic isolation nonlinear dynamic analysis uplift verification multiple superstructures/bases

Nonlinear dynamic analysis of multi-base seismically isolated structures with uplift potential Ⅰ:formulation

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2009年第3期8卷 421-431页

作者： Panos c.Tsopelas Panayiotis c.Roussis Michael c.constantinou Department of civil Engineering University of ThessalyVolosGreece Department of civil and Environmental Engineering University of CyprusNicosiaCyprus Department of civill Structural and Environmental EngineeringUniversity at BuffaloState University of New YorkBuffaloNYUSA

The complexity of modem seismically isolated structures requires the analysis of the structural, system and the isolation system in its entirety and the ability to capture potential discontinuous phenomena such as isolator uplift and their effects on the superstructures and the isolation hardware. In this paper, an analytical model is developed and a computational algorithm is formulated to analyze complex seismically isolated superstructures even when undergoing highly-nonlinear phenomena such as uplift. The computational model has the capability of modeling various types of isolation devices with strong nonlinearities, analyzing multiple superstructures （up to five separate superstructures） on multiple bases （up to five bases）, and capturing the effects of lateral loads on bearing axial forces, including bearing uplift. The model developed herein has been utilized to form the software platform 3D-BASIS-ME-MB, which provides the practicing engineering community with a versatile tool for analysis and design of complex structures with modem isolation systems.

关键词： friction-pendulum isolator, seismic isolation nonlinear dynamic analysis uplift multiple superstructures multiple bases

Bending waves of a rectangular piezoelectric laminated beam

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2020年第5期36卷 1099-1108,I0003页

作者： c.P.Wei c.X.Xue Department of Mechanics School of ScienceNorth University of ChinaTaiyuan 030051China

A simple nonlinear model is proposed in this paper to study the bending wave in a rectangular piezoelectric laminated beam of infinite *** on the constitutive relations for transversely isotropic piezoelectric materials and isotropic elastic materials,combined with some electric conditions,we derive the bending wave equation in a long rectangular piezoelectric laminated beam by using energy *** nonlinearity considered is geometrically associated with the nonlinear normal strain in the longitudinal beam *** shock-wave solution,solitary-wave solution and other exact solutions of the bending wave equation are obtained by the extended F-expansion *** by using the reductive perturbation method we derive the nonlinear Schrodinger(NLS)equation,further more,the bright and dark solitons are *** those soliton solutions,and some parameters derived by the process of solving soliton solutions,some conclusions are drawn by numerical analysis with some fixed conditions.

关键词： Bending wave Rectangular piezoelectric laminated beam Extended F-expansion method Nonlinear Schrodingereruation