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A Study on Some Causes of Rubble Mound Breakwater Failure

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China Ocean engineering 1996年第4期11卷 473-481页

作者： Zhang Fugui Ge Zhijin Senior engineer, River and Harbour Department, Nanjing hydraulic research Institute, Nanjing 210024 River and Harbour Department Nanjing Hydraulic Research Institute Nanjing 210024

Rubble mound breakwater, one of the protection structures, has been widely used in coastal and port engineering. Block stones were first used as its armor layer, and its use was limited to shallow sea areas where there is no large waves. Since the specially-shaped armor unit was developed, the rubble mound breakwater has become the main sort of the protection structures, which can be used in deep water zones where storm sometimes occurs. Owing to severe and complex surrounding conditions, the rubble mound breakwater failure sometimes occurs, thus the study on the causes of failure is of great importance. In the present study some breakwater failures at home and abroad are illustrated and the causes of failure are investigated from the point of view of design, test, construction and maintenance.

关键词： rubble mound breakwater protection structure breakwater failure

Experimental study on full-scale steel beam-to-column moment connections

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Earthquake engineering and engineering Vibration 2005年第2期4卷 311-323页

作者：钱稼茹余海群颜锋董海李建华刘月明 Department of Civil engineering Key Laboratory for Structural Engineering and Vibration of Ministry of EducationTsinghua UniversityBeijing 100084China Professor Beijing Urban engineering Architecture Design & research Institute Beijing 100037China SeniorEngineer Department of Civil engineering Key Laboratory for Structural Engineering and Vibration of Ministry of EducationTsinghua University Beijing 100084 China Engineer Beijing Urban engineering Architecture Design & research Institute Beijing 100037 China Engineer Beijing Urban engineering Architecture Design & research Institute Beijing 100037 China SeniorEngineer

Ten full-scale steel beam-to-column moment connections used in moment-resisting frames （MRFs） were tested to study the failure process, failure mode, strength and plastic rotation capacity. The specimens include one traditional welded flange-bolted web connection, one traditional fully welded connection, four beam flange strengthened connections, three beam flange weakened connections, and one through-diaphragm connection. The test results show that the connections with flange cover plates or with partly cut beam flanges satisfy the beam plastic rotation demand for ductile MRFs. From the measured stress profiles along the beam flange and beam web depth, the mechanics of brittle fracture at the end of the beam is discussed. Design recommendations for steel beam-to-column moment connections are proposed.

关键词： steel beam-to-column moment connection ductility plastic rotational experiment study

A semi-implicit three-dimensional numerical model for non-hydrostatic pressure free-surface flows on an unstructured,sigma grid

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International Journal of Sediment research 2013年第1期28卷 77-89页

作者： De-chao HU De-yu ZHONG Guang-qian WANG Yong-hui ZHU Senior engineer Yangtze River Scientific Research InstituteWuhan 430010China Senior engineer Yangtze River Scientific Research Institute State Key Laboratory of Hydroscience and engineering Tsinghua University Associate Professor State Key Laboratory of Hydroscience and EngineeringTsinghua University

A semi-implicit 3-D numerical formulation for solving non-hydrostatic pressure free-surface flows on an unstructured,sigma grid is ***-splitting and 9 semi-implicit methods are inherited and reformed from Casulli’s z-coordinate *** non-orthogonal sigma-coordinate transformation leads to additional terms. The resulting linear system for the non-hydrostatic correction is diagonally dominant but unsymmetric,and it is solved by the BiCGstab *** contrast with z-coordinate non-hydrostatic models,the new model fits vertical boundaries much better,which is important for the long-time simulation of sediment transport and riverbed deformation.A lock-exchange density flow is computed to determine whether the new scheme is able to simulate non-hydrostatic free-surface *** new model is further verified using the field data of a natural river bend of the lower Yangtze *** agreement between simulations and earlier research results,field data is obtained, indicating that the new model is applicable to hydraulic projects in real rivers.

关键词： Three-dimensional Non-hydrostatic pressure Semi-implicit Sigma-coordinate Unstructured grid

One-dimensional numerical simulation of non-uniform sediment transport under unsteady flows

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International Journal of Sediment research 2008年第4期23卷 316-328页

作者： Hongwei FANG 1,Minghong CHEN 2,and Qianhai CHEN 31 Prof.,Dept.of hydraulic engineering,Tsinghua Univ.,State Key Laboratory of Hydroscience and engineering,Beijing,100084,China 2 PhD,College of Water Conservancy and Civil engineering,China Agricultural Univ.,Beijing 100083,China.3 engineer,Institute of the Yangtze River research,Wuhan,430010,China Prof. Dept. of Hydraulic Engineering Tsinghua Univ. State Key Laboratory of Hydroscience and Engineering Beijing 100084 China PhD College of Water Conservancy and Civil Engineering China Agricultural Univ. Beijing 100083 China engineer Institute of the Yangtze River Research Wuhan 430010 China

One-dimensional numerical models are popularly used in sediment transport research because they can be easily programmed and cost less time compared with two-and three-dimensional numerical *** particular,they possess greater capacity to be applied in large river basins with many *** paper presents a one-dimensional numerical model capable of calculating total-load sediment *** cross-section-averaged sediment transport capacity and recovery coefficient are addressed in the suspended load *** one-dimensional model,therefore,can be applied to fine suspended loads and to hyperconcentrated flows in the Yellow ***,a new discretization scheme for the equation of unsteady non-uniform suspended sediment transport is *** model is calibrated using data measured from the Yantan Reservoir on the Hongshui River and the Sanmenxia Reservoir on the Yellow River.A comparison of the calculated water level and river bed deformation with field measurements shows that the improved numerical model is capable of predicting flow,sediment transport,bed changes,and bed-material sorting in various situations,with reasonable accuracy and reliability.

关键词： One-dimensional numerical model Sediment transport capacity Recovery coefficient Adaptation length Unsteady flow

AlTiN and AlTiON-coated hot work tool steels for tooling in steel thixoforming

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中国有色金属学会会刊：英文版 2010年第S3期20卷 1022-1028页

作者： Y.BIROL D.ISLER Materials Institute Marmara Research CentreGebzeKocaeliTurkey Department of Metallurgy and Materials engineer ing Istanbul Technical UniversityIstanbulTurkey

X32CrMoV33 hot work tool steel samples coated with AlTiN and AlTiON were submitted to thermal cycling under conditions that approximate thixoforming of steels and to sliding wear tests at 750 ℃,measured to be the cavity surface temperature shortly after the steel slurry is forced into the thixoforming *** and AlTiON coatings provide adequate protection against oxidation of the tool steel substrate,but fail to avoid thermal fatigue *** is attributed to the extensive softening of the substrate,the thermal expansion mismatch between the hot work tool steel and the coatings and residual compressive stresses inherited from the deposition *** impact of AlTiN and AlTiON coatings on the high temperature wear resistance,on the other hand,is *** improved wear resistance is attributed to the stable,protective surface oxide films.

关键词： thixoforming physical vapor deposition coating tooling steels thermal fatigue wear

Comparing carbon accumulation in restored and natural wetland soils of coastal Louisiana

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International Journal of Sediment research 2019年第6期34卷 600-607页

作者： Glenn M.Suir Charles E.Sasser Ronald D.DeLaune Elizabeth O.Murray U.S.Army engineer research and Development Center Environmental LaboratoryWetlands and Environmental Technologies Research Facility Louisiana State University Department of Oceanography and Coastal ScienceCollege of the Coast and Environment U.S.Army engineer research and Development Center Environmental Laboratory

Louisiana’s chronic wetland deterioration has resulted in massive soil organic matter loss and subsequent carbon release through *** combat these losses,and reestablish ecosystem function,goods,and services,many restoration projects have been constructed or planned throughout coastal *** are significant data gaps and conflicting results regarding wetland contributions to global warming,especially related to carbon sequestration in restored *** exceptionally large data set was used to derive carbon accumulation rates from key soil characteristics and *** and comparisons of bulk density,organic matter,total carbon,vertical accretion(short-and longer-term),and carbon accumulation rates were made across time(chronosequence) and space(i.e.,coastwide,watershed basins,and vegetation zones).Carbon accumulation rates in the Louisiana coastal zone were generally correlated to hydrogeomorphology,with higher rates occurring in zones of high river connectivity or in swamp or higher salinity tolerant *** average,naturally occurring wetlands had higher carbon accumulation rates than restoration *** some restoration measures were higher,and most showed increasing carbon accumulation rates over *** demonstrate that although wetland restoration provides many ecosystem benefits,the associated carbon sequestration may also provide useful measures for climate change management.

关键词： Wetland productivity Chronosequence Carbon sequestration Wetland restoration Coastal Louisiana

Comparison of tribological properties for graphite coatings used for remanufacturing

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Journal of Central South University 2005年第S2期14卷 41-44页

作者：朱玉岭 Systems engineering research Institute of engineer Equipment Beijing Beijing 100093 China

To improve the solid lubricity on the worn surface of frictional-pairs, a convenient and simple brush-painting technique was utilized to prepare the solid lubrication graphite coatings. The bonding between the coatings and substrate is good. To examine the influence of the different graphite contents on the tribological properties of the graphite coatings, the comparison experiments were carried out on the ring-on-block friction tester. The tribological results show a change law of saddle-shape between the tribological properties of graphite coatings and graphite content. When the amount of graphite is up to 28g, the tribological properties of graphite coating are the best. The excellent anti-friction of the graphite coating is associated with the close-packed hexagonal crystal structure of graphite.

关键词： remanufacturing graphite coatings solid lubrication tribological property

Adsorption and photocatalytic degradation of bisphenol A using TiO2 and its separation by submerged hollowfiber ultrafiltration membrane

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Journal of Environmental Sciences 2006年第1期18卷 193-200页

作者： Jae-Wook Lee Tae-Ouk Kwon Ramesh Thiruvenkatachari Il-Shik Moon Department of Chemistry engineer Seonam University Namwon 590-711 Korea Department of Chemistry engineer Sunchon National University Suncheon 540-742 Korea

This study evaluates the adsorption ability ofbisphenol A（BPA） on titanium dioxide（TiO2） and its effect on the photocatalysis by advanced oxidation process using UV radiation and TiO2 photocatalyst. Degradation of BPA was also evaluated for the system without adsorption prior to photocatalytic reaction. The separation of TiO2 from BPA solution treated by pilot-scale photocatalytic reactor （capacity 0.16 m^3） was studied using submerged ultrafiltration （UF） membrane. It was found that although adsorption capacity of BPA was not high, adsorption played an important role in improving the efficiency ofphotocatalysis. On the other hand, during the separation of TiO2 particles from aqueous suspension, the permeate flux of the membrane was strongly affected by transmembrane pressure and TiO2 dose. The permeate turbidity was decreased below 1 NTU.

关键词： bisphenol A TiO2 adsorption membrane photocatalysis

Local environment regulation of transition metal dichalcogenide-based single-atom catalysts

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Rare Metals 2024年第9期43卷 4019-4037页

作者： Ming-Hui Li Jing Li Xiao-Yu Zheng Yao Zhou Advanced research Institute of Multidisciplinary Science andSchool of Chemistry and Chemical engineering Beijing Institute of Technology Laser Micro/Nano Fabrication Laboratory School of Mechanical Engineering Beijing Institute of Technology

Single-atom catalysts have risen significant attention in the realm of green electrocatalytic energy conversion to address energy and environmental sustainability challenges. Transition metal dichalcogenide（TMD）-based single-atom catalysts are considered highly effective in electrocatalysis due to the TMDs' notable specific surface area, tunable elemental species and efficient utilization of single atoms. In order to enhance electrocatalytic performance, it is imperative to elaborately engineer the local environment surrounding the active sites of single atoms within TMDs. In this review, we initially explore the effects of synthesis methods on single-atom active sites and the influence of loading of single atoms on catalytic performance for TMDs. The modulation strategies of the local environment surrounding single-atom sites in TMDs are elaborated, including substitution engineering,surface adsorption, vacancies, spatial confinement and dual-atom site strategies. For each modulation strategy, the effects of diverse local environments on various electrocatalytic applications are presented, such as the oxygen evolution reaction, oxygen reduction reaction, nitrogen reduction reaction, CO2reduction reaction and CO oxidation. Ultimately, this study presents a comprehensive overview of the challenges encountered and the potential directions for the advancement of single-atom catalysts based on TMDs in the realm of electrocatalysis.

关键词： Electrocatalysis