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Cardiology Discovery 2023年第1期3卷 54-59页

作者： Xiaofeng He Lei Zhang Xuanze Liu Xiaozeng Wang The Department of Cardiology General Hospital of Northern Theater CommandShenyangLiaoning 110016China

A 43-year-old male was admitted to General Hospital of Northern Theater Command with exacerbation of chest pain for 10 *** tomographic angiography(CTA)showed an irregular aortic arch aneurysm involving the left subclavian artery(LSA),with penetrating aortic ulcer and intramural hematoma.A modified fenestrated thoracic endovascular aortic repair(TEVAR)technique was performed ***-up CTA showed that stent grafts were well-apposed,without endoleaks,migration,or branch artery occlusion,and the hematoma was almost completely *** this case,precise fenestrations were created by measurements based on three-dimensional CT reconstruction and ***,the physician chose an LSA approach to catch the guide wire and deployed branched stent grafts,considering the oblique direction of this branch and the small size of the *** case shows that pre-fenestrated and inner bare stent enhancing TEVAR is a safe and feasible technique for repair of complicated aortic arch aneurysm.

关键词： Aortic aneurysm Aortic arch Thoracic endovascular aortic repair Pre-fenestrated stent graft Branched stent graft Case report

Effects of rotational components of earthquake on seismic response of arch concrete dams

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Earthquake Engineering and Engineering Vibration 2020年第2期19卷 349-362页

作者： Amir Javad Moradloo Abbas Naiji Department of Civil Engineering School of EngineeringUniversity of ZanjanZanjan 38791-45371Iran

The present study deals with dynamic analysis of arch concrete dams,taking rotational components of earthquakes into account.A modified methodology was used to evaluate the rotational components of the *** translational components of the earthquake have been used in to obtain the rotational components of the earthquake,based on the intersecting isotropic elastic wave *** rotational components of Taft,Tabas and San-Fernando earthquakes are evaluated based on the translational components of the earthquakes and considering frequency dependencies of incident angle and wave ***,dynamic analyses of Morrow Point Dam are presented to evaluate the effects of combined translational and rotational components on the seismic response of the *** conditions of reservoirs,including full and empty state,are considered in the ***–structure interaction was completely taken into *** was realized that incorporating rotational components increased the maximum compressive and tensile stresses in both empty and full reservoir *** of maximum tensile stresses is very sensitive to the rotational components of the ***,it can be concluded that the segregated effect of the rocking component on the response of concrete dams is more effective than the sole effect of the torsional component.

关键词： rotational components earthquake arch concrete dam seismic analysis fluid-structure interaction

Reliability and variance-based sensitivity analysis of arch dams during construction and reservoir impoundment

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Frontiers of Structural and Civil Engineering 2019年第3期13卷 526-541页

作者： M.Houshmand KHANEGHAHI M.ALEMBAGHERI N.SOLTANI Department of Civil Engineering Shahid Beheshti UniversityTehranIran Department of Civil and Environmental Engineering Tarbiat Modares UniversityTehranIran

The static performance of arch dams during construction and reservoir impoundment is assessed taking into account the effects of uncertainties presented in the model properties as well as the loading *** arch dam is chosen as the case study;it is modeled along with its rock foundation using the finite element method considering the stage *** previous studies concentrated on simplified models and approaches,comprehensive study of the arch dam model along with efficient and state-of-the-art uncertainty methods are incorporated in this *** reliability method is performed to assess the safety level and the sensitivity analyses for identifying critical input factors and their interaction effects on the response of the *** sensitivity analysis based on improved Latin hypercube sampling is employed in this study to indicate the influence of each random variable and their interaction on variance of the *** levels of model advancement are considered for the dam foundation system:1)Monolithic dam without any joint founded on the homogeneous rock foundation,2)monolithic dam founded on the inhomogeneous foundation including soft rock layers,3)jointed dam including the peripheral and contraction joints founded on the homogeneous foundation,and 4)jointed dam founded on the inhomogeneous *** each model,proper performance indices are defined through limit-state *** this manner,the effects of input parameters in each performance level of the dam are *** outcome of this study is defining the importance of input factors in each stage and model based on the variance of the dam ***,the results of sampling are computed in order to assess the safety level of the dam in miscellaneous loading and modeling conditions.

关键词： concrete arch dams reliability randomness improved Latin hypercube sampling variance-based sensitivity analysis exceedance probability Sobol index

Chaos and Nonlinear Feedback Control of the arch Micro-Electro-Mechanical System

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Journal of Systems Science & Complexity 2018年第6期31卷 1510-1524页

作者： LUO Shaohua LI Shaobo TAJADDODIANFAR Farid Key Laboratory of Advanced Manufacturing Technology Ministry of EducationGuizhou UniversityGuiyang 550025China Schbol of Mechanical Engineering Guizhou UniversityGuiyang 550025China. Department of Mechanical Engineering Erik Jonsson School of Engineering and Computer ScienceThe Uni-versity of Texas at DallasRichardson TX 75080USA.

This paper addresses a nonlinear feedback control problem for the chaotic arch micro- electro-mechanical system with unknown parameters,immeasurable states and partial state-constraint subjected to the distributed electrostatic *** reflect inherent properties and design controller, the phase diagrams,bifurcation diagram and Poincare section are presented to investigate the nonlinear *** authors employ a symmetric barrier Lyapunov function to prevent violation of constraint when the arch micro-electro-mechanical system faces some *** RBF neural network system integrating with an update law is adopted to estimate unknown function with arbitrarily small error. To eliminate chaotic oscillation,a neuro-adaptive backstepping control scheme fused with an extended state tracking differentiator and an observer is constructed to lower requirements on measured states and precise system ***,introducing an extended state tracking differentiator avoids repeated derivative for the virtual control signal associated with conventional ***,simulation results are presented to illustrate feasibility of the proposed scheme.

关键词： arch micro-electro-mechanical system chaos suppression Neuro-adaptive backstepping nonlinear feedback control uncertainty.

Risk-based probabilistic thermal-stress analysis of concrete arch dams

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Frontiers of Structural and Civil Engineering 2019年第5期13卷 1007-1019页

作者： Narjes SOLTANI Mohammad ALEMBAGHERI Mohammad Houshmand KHANEGHAHI Department of Civil and Environmental Engineering Tarbiat Modares UniversityTehran ***Iran Department of Civil Engineering Shahid Beheshti UniversityTehran ***Iran

The probabilistic risk of arch dam failure under thermal loading is studied. The incorporated uncertainties, which are defined as random variables, are associated with the most affecting structural (material) properties o f concrete and thermal loading conditions. Karaj arch dam is selected as case study. The dam is numerically modeled along with its foundation in three-dimensional space;the temperature and thermal stress distribution is investigated during the operating phase. The deterministic thermal finite element analysis o f the dam is combined with the structural reliability methods in order to obtain thermal response predictions, and estimate the probability o f failure in the risk analysis context. The tensile overstressing failure mode is considered for the reliability analysis. The thermal loading includes ambient air and reservoir temperature variations. The effect o f solar radiation is considered by an increase in the ambient temperatures. Three reliability methods are employed: the first-order second-moment method, the first-order reliability method, and the Monte-Carlo simulation with Latin Hypercube sampling. The estimated failure probabilities are discussed and the sensitivity o f random variables is investigated. Although most of the studies in this line o f research are used only for academic purposes, the results of this investigation can be used for both academic and engineering purposes.

关键词： arch dams probabilistic analysis thermal stress sensitivity reliability

Deformation reinforcement theory and its application to high arch dams

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Science China(Technological Sciences) 2008年第S2期51卷 32-47页

作者： YANG Qiang,LIU YaoRu,CHEN YingRu & ZHOU WeiYuan State Key Laboratory of Hydroscience and Hydraulic Engineering,Tsinghua University,Beijing 100084,China State Key Laboratory of Hydroscience and Hydraulic Engineering Tsinghua University Beijing China

In this paper,the deformation reinforcement theory(DRT) proposed by the authors is elaborated with a new definition of instability that an elasto-plastic structure is not stable if it cannot satisfy simultaneously equilibrium condition,kinematical admissibility and constitutive equations under the prescribed *** from the definition,a proof is established to the principle of minimum plastic complementary energy for failured *** is revealed that the principle of mini-mum plastic complementary energy results in relaxed constitutive equations,especially,yield *** is demonstrated with case studies that many key issues in arch dam design,e.g.,global stability,dam-toe reinforcement,dam-toe cracking,dam-abut-ment reinforcement,can be well solved within the framework of the deformation reinforcement *** structural global stability can be described by the curve of the plastic complementary energy vs overloading *** unbalanced-forces obtained by elasto-plastic FEM can be used as the basis of analysis of global stability,dam-heel cracking,dam-toe anchorage and reinforcement of faults of high arch dams and their foundations.

关键词： high arch dams global stability reinforcement unbalanced force plastic complementary energy

PDGF signaling from pharyngeal pouches promotes arch artery morphogenesis

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Journal of Genetics and Genomics 2019年第12期46卷 551-559页

作者： Aihua Mao Mingming Zhang Jie Liu Yu Cao Qiang Wang State Key Laboratory of Membrane Biology Institute of ZoologyUniversity of Chinese Academy of SciencesChinese Academy of SciencesBeijing100101China Institute for Stem Cell and Regeneration Chinese Academy of SciencesBeijing100101China

The great vessels of the heart originate from the pharyngeal arch arteries(PAAs).Anomalies of the PAAs often occur together with pharyngeal pouch malfo rmations,but the reasons for this phenomenon are not fully *** the current study,we show that platelet-derived growth factor(PDGF)signaling derived from the pharyngeal pouches plays an important function in PAA vasculogenesis,During PAA development in zebrafish embryos,pdgfaa and pdgfab are expressed in the developing pharyngeal *** from loss-of-function experiments revealed a critical role of these genes in PAA *** found that nitroreductase(NTR)-mediated pouch ablation distinctly decreased PDGF receptor tyrosine phosphorylation,yielding a severe loss of ***,pouch-specific overexpression of pdgfaa in pdgfaa-/-;pdgfab-/-mutants significantly relieved the PAA defects,which indicated a primary role of pharyngeal pouch-expressed PDGF ligands in signal activation and PAA *** findings further showed that PDGF signaling was indispensable for the proliferation of PAA ***,these results established a role for PDGFaa-and PDGFab-mediated tissuetissue interaction during PAA development.

关键词： PDGFαa PDGFαb Pharyngeal pouch Pharyngeal arch artery Tissue-tissue interaction Zebrafish

Study on real working performance and overload safety factor of high arch dam

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Science China(Technological Sciences) 2008年第S2期51卷 48-59页

作者： ZHANG GuoXin,LIU Yi & ZHOU QiuJing Department of Structures and Materials,China Institute of Water Resources and Hydropower Research,Beijing 100038,China Department of Structures and Materials China Institute of Water Resources and Hydropower Research Beijing China

Considering the fact that high arch dams have problems such as complicated stress,high cost,and hazards after being damaged,this paper intends to study the effects of load,material strength,and safety analysis method on dam safety and working performance of arch *** this article,the effects of temperature,self weight exaction way and water loading on structure response are first discussed,and a more reasonable way of considering is then put *** taking into consideration the mechanical property of materials and comparing the effects of different yield criteria on overloading safety of high arch dams,this paper concludes that brittle characteristics of concrete should be fully considered when conducting safety assessment for high arch dams to avoid overestimating the bearing capacity of the *** comparing several typical projects,this paper works out a safety assessment system of multiple safety and relevant engineering analogical analysis methods,which is closer to the actual situation,and thus is able to assess the response of high arch dam structure in a more comprehensive way,elicit the safety coefficients in different situations,and provide a new way of considering the safety assessment of high arch dams.

关键词： high arch dam real working performance safety load strength safety assessment method

Concrete-Filled Steel Tube arch Bridges in China

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Engineering 2018年第1期4卷 143-155页

作者： Jielian Zheng Jianjun wang College of Civil Engineering and architecture Guangxi University Nanning 530004 China Guangxi Communications Investment Group Co. Ltd. Nanning 530022 China Guangxi Road and Bridge Engineering Group Co. Ltd. Nanning 530011 China

In the past 20 years, great progress has been achieved in China in the construction of concrete-filled steel tube (CFST) arch bridges and concrete arch bridges with a CFST skeleton. The span of these bridges has been increasing rapidly, which is rare in the history of bridge development. The large-scale construction of expressways and high-speed railways demands the development of long-span arch bridges, and advances in design and construction techniques have made it possible to construct such bridges. In the present study, the current status, development, and major innovative technologies of CFST arch bridges and concrete arch bridges with a CFST skeleton in China are elaborated. This paper covers the key construction technologies of CFST arch bridges, such as the design, manufacture, and installation of steel tube arch trusses, the preparation and pouring of in-tube concrete, and the construction of the world’s longest CFST arch bridge—the First Hejiang Yangtze River Bridge. The main construction technologies of reinforced concrete arch bridges are also presented, which include cable-stayed fastening-hanging cantilever assembly, adjusting the load by means of stay cables, surrounding the concrete for arch rib pouring, and so forth. In addition, the construction of two CFST skeleton concrete arch bridges—the Guangxi Yongning Yong River Bridge and the Yunnan–Guangxi Railway Nanpan River Bridge—is discussed. CFST arch bridges in China have already gained a world-leading position; with the continuous innovation of key technologies, China will become the new leader in promoting the development of arch bridges.

关键词： Concrete-filled steel tube (CFST) arch bridge Steel-reinforced concrete arch bridge Cable-stayed fastening-hanging cantileverassembly Vacuum-assisted pouring in-tube concrete Adjusting load by stay cables

On the obstacles and way to assess the seismic catastrophe for high arch dams

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Science China(Technological Sciences) 2007年第Z1期50卷 11-19页

作者： CHEN HouQun China Institute of Water Resources and Hydropower Research (IWHR) Beijing 100044China

To prevent possible seismic catastrophe, naturally, its assessment is deeply concerned over in China as a series of arch dams of about 300 m high will be constructed in the severe seismic regions. In this paper the major obstacles to the seismic catastrophe assessment of high arch dams which focused on clearly defining the Maximum Credible Earthquake (MCE) and reasonably selecting its site-specific seismic input parameters as well as quantitatively evaluating the limit state of dam-breach for designers are emphasized. Some breakthrough progress with pending problems is presented, such as to adopt more reasonable seismic input parameters based on seismic hazard evaluation of dam site; to develop model and method more fit in with the reality for non-linear seismic analysis of dam-foundation-reservoir system. The ideals of further improvement both in evaluating the MCE and defining the quantitative index of its performance objective are discussed, including how to use semi-empirical method of simulating strong ground motion near fault, how to solve the long-standing problem of stress singularity at dam heel, and how to investigate dynamic behaviors of fully-graded dam concrete through dynamic tests and 3-dimensional meso-mechanics analysis checked by CT technique.

关键词： seismic catastrophe assessment high arch dam maximum credible earthquake quantitative evaluation of dam-breach finite fault method fully-graded dam concrete 3-dimensional meso-mechanics analysis CT technique