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Test analysis on prestressed concrete composite beams with steel boxes subjected to torsion and combined flexure and torsion

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Science China(Technological Sciences) 2012年第12期55卷 3302-3310页

作者： HU ShaoWei CHEN Liang Nanjing hydraulic research institute Nanjing 210029China research Center on New Materials in hydraulic Structures Ministry of Water ResourcesNanjing 210029China

While modem prestressed techniques have improved the torsion properties of high-strength concrete （HSC） composite beams with prestressed steel （PS） boxes, no research has been reported in either the national or international literature on the an- ti-torque and composite torque properties of this type of beam. With the aim of understanding the torque properties of these beams, this paper presents results of ten comprehensive tests; three of these were based on stirrup spacings and prestressing levels as the main parameters, while the other seven were based on torsional rates. The torsion tests were conducted on the re- sults which established several key parameters, including curves of constant torsion, strain curves of steel torsion, strain distri- bution of steel beams and concrete, curves of bending-moment and mid-span deflection, as well as cross strain *** prestressing impact-factor method was adopted to deduce semiempirical equations for cracking torque in such composite beams. Furthermore, this involves the use of the equation of ultimate torque based on tress-model-theory of the distortion an- gle, the calculated results show good agreement with the measured values. In summary, this paper offers theoretical analysis for future applications of HSC composite beams with PS boxes, and provides both validation of the methods employed and a reference point for on-going research on composite beams and related anti-torque studies.

关键词： high-strength concrete composite beams prestressed steel boxes torsion property cracking torque ultimate torque combined torsion torsion-bending correlation equation

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Derivation of Parametric Tropical Cyclone Models for Storm Surge Modeling

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China Ocean Engineering 2010年第2期24卷 245-254页

作者：王志力陆永军耿艳芬 State Key Laboratory of Hydrology-Water Resources and hydraulic Engineering Nanjing Hydraulic Research Institute Transportation College Southeast University

In this paper, the parametric tropical cyclone models for storm surge modeling are further developed. Instead of tangential wind speed via cyclostrophic balance and radial wind speed using a simple formulation of defection angle, the analyrical expressions of tangential and radial wind speed distribution are derived from the governing momentum equations based on the general symmetric pressure distribution of Holland and Fujita. The radius of the maximum wind is estimated by tropical cyclone wind structure which is characterized by the radial extent of special wind speed. The shape parameter in the pressure model is estimated by the data of several tropical cyclones that occurred in the East China Sea. Finally, the Fred cyclone （typhoon 199417） is calculated, and comparisons of the measured and calculated air pressures and wind speed are presented.

关键词： tropical cyclone parametric tropical cyclone model storm surge radius of maxirmun wind shapeparameter

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Two-dimensional shallow water equations with porosity and their numerical scheme on unstructured grids

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Water Science and Engineering 2013年第1期6卷 91-105页

作者： Zhi-li WANG Yan-fen GENG State Key Laboratory of Hydrology-Water Resources and hydraulic Engineering Nanjing Hydraulic Research Institute School of Transportation Southeast University

In this study, porosity was introduced into two-dimensional shallow water equations to reflect the effects of obstructions, leading to the modification of the expressions for the flux and source terms. An extra porosity source term appears in the momentum equation. The numerical model of the shallow water equations with porosity is presented with the finite volume method on unstructured grids and the modified Roe-type approximate Riemann solver. The source terms of the bed slope and porosity are both decomposed in the characteristic direction so that the numerical scheme can exactly satisfy the conservative property. The present model was tested with a dam break with discontinuous porosity and a flash flood in the Toce River Valley. The results show that the model can simulate the influence of obstructions, and the numerical scheme can maintain the flux balance at the interface with high efficiency and resolution.

关键词： shallow water equations with porosity source term," Roe-type Riemann solver," finitevolume method unstructured grid

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Characteristics of Water and Sediment Exchange Between Yangtze Estuary and Hangzhou Bay

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China Ocean Engineering 2007年第2期21卷 255-266页

作者：孔俊宋志尧夏云峰章卫胜 State Key Laboratory of Hydrology-Water Resources and hydraulic Engineering College of OceanHohai University Nanjing hydraulic research institute

Based on the 2-D flow and sediment numerical model of the Yangtze Estuary and the Hangzhou Bay, the characteristics of water and sediment exchange in their joint waters is studied through quantitative calculation and analysis of the characteristics of water flow and sediment transportation. The results show that there is periodical water and sediment exchange in this joint waters, that the net water exchange appears mainly between 0 - 6 m depth （theoretical datum plane, the same below） offshore and the maximum is near the depth of 2 m, and that the net sediment exchange mainly appears between 0 - 5 m depth and the maximum is near the depth of 3 m, indicating that the range of water flow passage is different from that of sediment transport from the Yangtze Estuary to the Hangzhou Bay. Combined with the results of numerical simulation, this paper also analyzes the hydrodynamical mechanism influencing water and sediment exchange between the Yangtze Estuary and the Hangzhou Bay, including tidal fluctuation, tidal current kinetic energy, tide-induced residual current and the trace of water particles. Finally, the sediment transportation passage on the Nanhui tidal fiat is discussed, and the results show that sediment is transported into the Hangzhou Bay from the south side of Shipilei, while sediment is brought back to the South Channel of the Yangtze Estuary from the north side.

关键词： tidal fluctuation residual current tidal flow kinetic energy tidal ctu'rent flux sediment transport flux

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Adaptive criterion curves describing incipient motion of sediment under wave and current conditions

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International Journal of Sediment research 2021年第5期36卷 616-627页

作者： Shouqian Li Yongjun Lu Dano J.A.Roelvink State Key Laboratory of Hydrology Water Resources and hydraulic Engineering Science Nanjing Hydraulic Research Institute

Sediment incipient motion is a fundamental issue in sediment transport theory and engineering *** Shields curve often is used to determine the threshold of sediment movement under unidirectional current conditions, it is unclear whether it can be directly applied for the wave or combined wavecurrent conditions. The study developed adaptive criterion curves describing incipient motion of sediment under wave and current conditions based on the flow pattern around the sediment ***, the flow pattern law for fixed particles was recognized based on the friction law under various dynamic conditions(wave, current, and their combinations), and the flow pattern demarcations for incipient sediment motion were obtained with the threshold conditions for sediment movement under various dynamic conditions combined. Secondly, the exact shape of the Shields curve in each flow regime was derived under the current condition. By combining the flow pattern demarcations for incipient sediment motion under the wave condition, the criterion curve under the wave condition was *** combining the flow pattern demarcations for incipient sediment motion under the combined currentwave condition, the criterion curve for sediment incipient motion under the combined current-wave condition was derived. The results indicated that the flow pattern around incipient particles includes laminar, laminar-rough turbulent transition, and rough turbulent regimes. The criterion curves for sediment incipient motion under various dynamic conditions stayed the same in the laminar and rough turbulent regimes, but different in the transition regime. Depending on the relative strengths of the currents and waves, the shape of the criterion curve under the combined current-wave condition transitions adaptively between the criterion curve under the current condition and the criterion curve under the wave conditions.

关键词： Current Wave Incipient motion of sediment Adaptive criterion curve Flow pattern law

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A functional tacrolimus-releasing nerve wrap for enhancing nerve regeneration following surgical nerve repair

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Neural Regeneration research 2025年第1期20卷 291-304页

作者： Simeon C.Daeschler Katelyn J.W.So Konstantin Feinberg Marina Manoraj Jenny Cheung Jennifer Zhang Kaveh Mirmoeini JPaul Santerre Tessa Gordon Gregory HBorschel SickKids research institute Neuroscience and Mental Health ProgramTorontoONCanada institute of Biomaterials and Biomedical Engineering University of TorontoTorontoONCanada Indiana University School of Medicine IndianapolisINUSA Division of Plastic and Reconstructive Surgery the Hospital for Sick ChildrenTorontoONCanada Translational Biology and Engineering Program Ted Rogers Centre for Heart ResearchInstitute of Biomedical EngineeringFaculty of DentistryUniversity of TorontoTorontoONCanada

Axonal regeneration following surgical nerve repair is slow and often incomplete,resulting in poor functional recovery which sometimes contributes to lifelong ***,there are no FDA-approved therapies available to promote nerve *** accelerates axonal regeneration,but systemic side effects presently outweigh its potential benefits for peripheral nerve *** authors describe herein a biodegradable polyurethane-based drug delivery system for the sustained local release of tacrolimus at the nerve repair site,with suitable properties for scalable production and clinical application,aiming to promote nerve regeneration and functional recovery with minimal systemic drug *** is encapsulated into co-axially electrospun polycarbonate-urethane nanofibers to generate an implantable nerve wrap that releases therapeutic doses of bioactive tacrolimus over 31 *** and drug loading are adjustable for applications in small and large caliber nerves,and the wrap degrades within 120 days into biocompatible *** released from the nerve wrap promotes axon elongation in vitro and accelerates nerve regeneration and functional recovery in preclinical nerve repair models while off-target systemic drug exposure is reduced by 80%compared with systemic *** its surgical suitability and preclinical efficacy and safety,this system may provide a readily translatable approach to support axonal regeneration and recovery in patients undergoing nerve surgery.

关键词： biodegradable local drug delivery nerve injury nerve regeneration nerve wrap tacrolimus

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Temporal dynamics of neonatal hypoxic-ischemic encephalopathy injuries on magnetic resonance imaging

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Neural Regeneration research 2025年第11期20卷 3144-3150页

作者： Holly Flyger Samantha J.Holdsworth Alistair J.Gunn Laura Bennet Hamid Abbasi Mātai Medical research institute Tairāwhiti GisborneNew Zealand Department of Anatomy&Medical Imaging Faculty of Medical and Health SciencesThe University of AucklandAucklandNew Zealand Center for Brain research The University of AucklandAucklandNew Zealand Auckland Bioengineering institute The University of AucklandAucklandNew Zealand

Moderate to severe perinatal hypoxic-ischemic encephalopathy occurs in~1 to 3/1000 live births in high-income countries and is associated with a significant risk of death or neurodevelopmental *** assessment is important to help identify highrisk infants,to help families,and to support appropriate interventions.A wide range of monitoring tools is available to assess changes over time,including urine and blood biomarkers,neurological examination,and *** present,magnetic resonance imaging is unique as although it is expensive and not suited to monitoring the early evolution of hypoxic-ischemic encephalopathy by a week of life it can provide direct insight into the anatomical changes in the brain after hypoxic-ischemic encephalopathy and so offers strong prognostic information on the long-term outcome after hypoxic-ischemic *** review investigated the temporal dynamics of neonatal hypoxic-ischemic encephalopathy injuries,with a particular emphasis on exploring the correlation between the prognostic implications of magnetic resonance imaging scans in the first week of life and their relationship to long-term outcome prediction,particularly for infants treated with therapeutic hypothermia.A comprehensive literature search,from 2016 to 2024,identified 20 pertinent *** review highlights that while the optimal timing of magnetic resonance imaging scans is not clear,overall,it suggests that magnetic resonance imaging within the first week of life provides strong prognostic *** challenges limit the timing consistency,particularly the need for intensive care and clinical ***,although most reports examined the prognostic value of scans taken between 4 and 10 days after birth,there is evidence from small numbers of cases that,at times,brain injury may continue to evolve for weeks after *** suggests that in the future it will be important to explore a wider range of times after hypo

关键词： magnetic resonance imaging neonatal hypoxic-ischemic encephalopathy neurodevelopmental outcomes prognostic biomarkers in neuroimaging scan timing therapeutic hypothermia

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State of seawater intrusion and its adaptive management countermeasures in Longkou City of China

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Journal of Groundwater Science and Engineering 2020年第1期8卷 30-42页

作者： ZHONG Hua-ping WU Yong-xiang Nanjing hydraulic research institute

Longkou City is a coastal area,and lacks water *** overexploitation of groundwater causes seawater *** present,seawater intrudes an area of 68 *** the decrease of groundwater extraction,the seawater intrusion area has generally *** paper expounds the development process of seawater intrusion as well as the corresponding prevention and control measures of using groundwater replenishment and groundwater throttling in Longkou *** view of the seawater intrusion problem in Longkou City,some adaptive management countermeasures are put forward,which include:Adjusting industrial and agricultural structure,promoting economic and social development to match water resources;improving water usage structure,optimizing the utilization of water resources;advancing the construction of a water-saving society,using water resources efficiently;implementing inter-basin water transfer,using water resources rationally;developing and utilizing unconventional water sources,making full use of water resources;strengthening water infrastructure construction,increasing the development and utilization potential of water resources;carrying out ecological restoration,protecting water resources and ecological environment;improving the management informationalization level,strengthening the capabilities of groundwater monitoring and management;increasing publicity,improving public awareness of participation.

关键词： Seawater intrusion Groundwater Adaptive management Countermeasures Longkou City

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Beginning from the end:the presynaptic terminal as a pathomechanism hub in frontotemporal dementia and amyotrophic lateral sclerosis

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Neural Regeneration research 2025年第11期20卷 3217-3218页

作者： Laura Huggon Emma L.Clayton UK Dementia research institute at King’s College London LondonUK Department of Basic and Clinical Neuroscience Institute of Psychiatry Psychology&NeuroscienceKing’s College LondonLondonUK

Frontotemporal dementia and amyotrophic lateral sclerosis:Frontotemporal dementia(F T D)and amyo t rophic lateral sclerosis(ALS)are neurodegenerative diseases with significant overlapping *** these neurodegenerative diseases affect different neuronal populations(with FTD affecting neurons of the frontal and temporal lobes,and ALS affecting upper and lower motor neurons),these two diseases are complexly *** and ALS exist on a disease spectrum,with shared genetic causes,clinical presentations,and pathologies.

关键词： diseases amyotrophic sclerosis

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Flow structure and unsteady fluctuation with separation over a two-dimensional backward-facing step

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Journal of Hydrodynamics 2019年第6期31卷 1204-1217页

作者： Fang-fang Wang Shi-qiang Wu Biao Huang State Key Laboratory of Hydrology-Water Resources and hydraulic Engineering Nanjing Hydraulic Research InstituteNanjing 210029China Smart Cities institute Zhengzhou UniversityZhengzhou 450001China

The flow over a backward-facing step(BFS)is a typical separation and reattachment *** flow structures and unsteady mechanisms are still not well *** this paper,the global velocity fields of a BFS are obtained by a synchronous particle image velocimetry(PIV)system with Reh=5345(Reynolds number)and Er=2(expansion ratio).Flow structures are distinguished and defined by the fraction of the negative velocity(upn).The reattachment zone(Lr)is quantitatively defined as(u0.9,u/0.1)on the bottom *** distribution of the large-scale vortices couples well with the divided flow structures and their temporal evolution presenting four stages(forming,developing,shedding and redeveloping)when travel *** unsteady motions with various low frequencies are well explained by the coherent vortices and flow *** the unsteady low frequency motions,the Kelvin Helmholtz(KH)vortices and the oscillation of Xr(OX)come likely from the free shear *** KH vortices contribute to the unsteadiness of the temporal flow,and the OX is the primary response to the vortical fluctuations.

关键词： Backward-facing step flow structure large-scale vortices unsteady motion free shear layer

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