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Characteristics of vertical ozone distribution in the lower troposphere in the Yangtze River Delta at Lin'an in the spring of 2.01

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Science china Earth Sciences 2005年第9期48卷 1519-1528页

作者： ZHENG Xiangdong1, CHAN Chuenyu2. CUI hong2. QIN Yu3, CHAN Loyan2. ZHENG Yongguang3 & LEE Yusiang2.1. Chinese Academy of Meteorological Sciences, Beijing 100081, china {2., hong kong polytechnic university, hung hom, hong kong, china 3. department of Atmospheric Sciences, Peking university, Beijing 100871, china 1. Chinese Academy of Meteorological Sciences 100081 Beijing China 2. department of civil and structural engineering Hong Kong Polytechnic University Hung Hom Hong Kong China 3. department of Atmospheric Sciences Peking University 100871 Beijing China

We analyzed vertical distributions of ozone (O3) in the lower troposphere (< 5 km above ground) at Lin’an (119.75°E, 30.30°N), Zhejiang Province using electrochemical concen- tration cell (ECC) ozonesonde data obta... 详细信息

We analyzed vertical distributions of ozone (O3) in the lower troposphere (2. to April 13, 2.01. The results showed that the vertical O3 distributions are controlled by metrological conditions and the char- acteristics of O3 profiles are related to those of wet bulb potential temperature and wind field. O3 below 2.km showed that the strongest variability and enhanced O3 mixing ratios were associated with easterly winds that blow pollutants from the upwind source region of the Yangtze River Delta (YRD) region. Vertical O3 profiles below 5 km can be grouped into 5 categories: (1) peak mixing ratio type, (2. well-mixed type, (3) layered-structure type, (4) episodic pollution type and (5) alti- tudinal increasing type. Vertical distributions of O3 affected by regional transport of polluted air masses were investigated. Transport of polluted air from high latitudes of northern china, ac- companying subsiding motion of air and stagnant atmospheric conditions are important factors that lead to high mixing ratios of O3 at Lin’an. The stagnant atmospheric conditions associated with a continental high pressure system and pollution plume transported from the YRD and cen- tral-eastern china also lead to regional accumulation of O3 and high O3 mixing ratio at Lin’an. Long-range transport of O3 and pollutants from the Pearl River Delta in South china and in-situ O3 formation also resulted in elevated O3 mixing ratios at around 1 km altitudes and layered O3 distribution in the lower troposphere.

关键词： vertical ozone distribution, lower troposphere, Yangtze River Delta, Lin'an.

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Properties of Cementitious Rendering Mortar Prepared with Recycled Fine Aggregates

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Journal of Wuhan university of Technology(Materials Science) 2010年第6期25卷 1053-1056页

作者：潘智生 department of civil and {2. engineering The Hong Kong Polytechnic University

The results of an experimental study on investigating the properties of cementitious rendering mortars prepared with a recycled fine aggregate（RA） were *** RA was obtained from a recycling plant in which mixed demolition wastes were processed by mechanical crushing,sieving and sorting *** series of rendering mortar mixes were prepared with a constant water/cement and a constant aggregate/cement ratios of 0.55 and 3 *** sand and natural crushed rock fine were originally used in the two series separately,and they were consistently replaced by 2.%,50%,75% and 100% by the recycled *** experimental results showed that mechanical properties,such as compressive strength,flexural strength and modulus of elasticity of the mortars prepared with the RA were lower than the mortars made with the natural ***,the bond strength at the interface between the mortar and masonry bricks determined by the Triplet test was found to be higher for the mortars prepared with the RA.

关键词： rendering mortar recycled fine aggregate triplet test mechanical properties

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Some Consideration on Elastic Pile Foundation Analysis by Poulos

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岩石力学与工程学报 2001年第6期20卷 882-885页

作者： Cheng Yungming (department of civil and {2. engineering, The hong kong polytechnic university, hong kong, china) 香港工业大学香港

The elastic pile foundation analysis by Poulos is well developed and has been adopted by some countries in their design guideline. In die vertical load analysis, the author has discovered that the approach by Poulos is sensitive to the number of segments used fix-analysis and can lead to some unreasonable results for pile in finite depth of soil. In the lateral load analysis, the group interaction factor which is claimed to be a linear relation of the departure angle β by Poulos is found to be a linear relation of sin2.β by the author.

关键词： pile elastic analysis vertical and horizontal load

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Experimental study of human-induced effects on floor slab of an ancient Tibetan structure

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Earthquake engineering and engineering Vibration 2012年第4期11卷 513-523页

作者： Yang Na Guo Ting S.S. Law School of civil engineering Beijing Jiaotong University civil and structural {2. department Hong Kong Polytechnic University

With the opening of ancient Tibetan structures to visitors worldwide, human load has become the principal live load on these structures. This project studies the properties of the floor structure of an ancient Tibetan building and its behavior under human-induced load effects. Tests were conducted with static and dynamic crowd load, including stepping and jogging by people at a fixed position. The tests show that the floor structure does not behave as a continuous slab. It takes the load from local areas with minimal load transference properties. The acceleration response shows significant peaks when the footstep frequency is close to the natural frequency of the s~＇ucture, but the human jogging excitation frequency does not have any obvious effect on the structural response. The elastic modulus of the Agatu material is estimated to be close to zero from the measured natural frequency of the slab. The Agatu material is concluded to be a discrete compacted material with insignificant contribution to the structural rigidity of the floor slab.

关键词： ancient Tibetan structure crowd load static dynamic floor slab Agatu elastic modulus

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Template synthesis of N——F-codoped TiO_2.nanotubes with high visible light activity

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Science china Chemistry 2009年第12期52卷 2043-2046页

作者： PAN SuJuan1,LIANG HaiChao2.WANG ChangQing1,YANG FuWei1,LI XiaoDong1 & YANG Sheng1 1 department of Life Science and Chemistry,Tianshui Normal university,Tianshui 741000,{2. 2.department of civil and structural engineering,The hong kong polytechnic university,hong kong,{2. 1. department of Life Science and Chemistry Tianshui Normal University Tianshui 741000 China 2. department of civil and structural engineering The Hong Kong Polytechnic University Hong Kong China

A series of highly ordered N-F-codoped TiO2.nanotubes were synthesized with a simple template technique and the obtained samples were detected by FE-SEM and XPS. The UV-Vis absorption spectrum showed that after N-F-codoping,TiO2.nanotubes had a new absorption band at 42. nm,leading to a photoresponse in the visible region. These modified nanotubes showed a significant visibleinduced photocatalytic activity for the degradation of methylene blue in aqueous solution.

关键词： TiO2 nanotubes codoping photocatalytic activity

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A LARGE EDDY SIMULATION TURBULENCE MODEL FOR COASTAL SEAS AND SHALLOW WATER PROBLEMS

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Journal of Hydrodynamics 2001年第4期13卷 24-27页

作者： Zhan, Jie-Min Li, Yok-Sheung Dept. of Appl. Mech. and Eng. Zhongshan Univ. Guangzhou 510275 China

In large scale motions of circulations in coastal seas and shallow-water problems, different characteristics of flow in the horizontal plane and in the vertical direction are expected. A new large eddy simulation model was proposed. There are some differences between the present method and the other LES models. The philosophy of the large eddy simulation and the directional eddy viscosity method were applied in the horizontal plane and in the vertical direction, respectively. Compared with the other LES models in which there is no difference between horizontal viscosity and vertical viscosity, the proposed method is reasonable.

关键词： Computational fluid dynamics Computer simulation

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CHEBYSHEV FINITE SPECTRAL METHOD FOR 2.D EXTENDED BOUSSINESQ EQUATIONS

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Journal of Hydrodynamics 2011年第1期23卷 1-11页

作者： LI Yok-sheung ZHAN Jie-min, SU Wei department of civil and {2. engineering The Hong Kong Polytechnic University Hong Kong China department of Applied Mechanics and engineering Sun Yat-sen University Guangzhou 510275 China

In this article,an accurate Chebyshev finite spectral method for the 2.D extended Boussinesq equations is *** method combines the advantages of both the finite difference and spectral *** Adams-Bashforth predictor and the fourth-order Adams-Moulton corrector are adopted for the numerical solution of the governing differential *** efficient wave absorption strategy is also proposed to effectively absorb waves at outgoing wave boundaries and reflected waves from the interior of the computational domain due to barriers and bottom slopes at the incident wave boundary to avoid contamination of the specified incident wave *** proposed method is verified by a case where experimental data are available for comparison for both regular and irregular *** case is wave diffraction over a shoal reported by Vincent and *** results agree very well with the corresponding experimental data.

关键词： Chebyshev polynomial finite spectral method irregular waves

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THREE-DIMENSIONAL LARGE EDDY SIMULATION OF FREE SURFACE TURBULENT FLOW IN OPEN CHANNEL WITHIN SUBMERGED VEGETATION DOMAIN

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Journal of Hydrodynamics 2003年第3期15卷 35-43页

作者： SuXiao-hui LiC.W ChenBi-hong CollegeofcivilandHydraulicengineering DalianUniversityofTechnologyDalian116024China departmentofciviland{2.engineering HongKongPolytechnicUniversityHongKongChina

A three-dimensional Large Eddy Simulation (LES) has been performed ofhydrodynamic behavior of turbulent flow in open channel that the lower part of the domain isoccupied by a drag force layer to represent vegetation. One equation model is used to closing theresolvable scale equations. The turbulent characteristic length is parameterized by a k-l model. Aphenomenal model is employed to express the performance of vegetation in the open channel. Theresult reveals that the present model has the capacity of describing three-dimensional structure oflarge eddy appearing in turbulent flow in open channel with vegetation region and has the capacityof tracing the development of large eddies.

关键词： LES turbulent flow open channel vegetation

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THREE-DIMENSIONAL NUMERICAL MODELINGOF COHESIVE SEDIMENT TRANSPORT BY TIDAL CURRENTIN PEARL RIVER ESTUARV

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International Journal of Sediment Research 1999年第2期14卷 107-123页

作者： Yong CHEN1, Onyx W.H. WAI2. Y. S. Li3 and Qimiao LU4 (l 2.3 department of civil and {2. engineering, The hong kong polytechnic university. hung hom, Kowloon, hong kong 4,department of civil engineering, Daltech, Dalhousie university, Halifax, Can

A three-dimensional numerical model of suspended sediment transport taking into account the effects of cohesiveness between sediments is presented. An efficient operator splitting scheme is employed to solve the equations of mass conservation, momentum and suspended sediment transport. The splitting method partitions a time step into three fractional time steps according to physical phenomena. In the first step, advection and Coriolis force are solved by Eulerian-Lagrangian method (ELM). Horizontal diffusion is approximated by implicit finite element method (FEM) for each horizontal layer in the second step. In the last step, vertical diffusion and pressure gradient are discretized by implicit finite difference method (FDM) for each nodal column. The continuity equation is solved by implicit FEM within an entire time step. The sigma coordinate system for vertical columns and nine-node isoparameteric finite elements for horizontal planes are employed in the model. Empirical functions specifically developed for cohesive sediments in china have been incorporated into the model. The model has been applied to investigate the suspended sediment concentration and seabed evolution in the Pearl River Estuary (PRE) in china. Computed results show that the distribution of sediment concentration and seabed evolution is in agreement with field measurements. In addition, the effect of the size of time step on result is discussed. The computed result shows that larger time steps can be used in this model for saving computation time without losing much accuracy.

关键词： Cohesive sediment Sediment transport model Finite element method Eulerian-Lagrangian method.

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In-line response of vertical cylinders in regular and random waves

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Acta Oceanologica Sinica 2007年第6期26卷 124-138页

作者： LI Yok-sheung SU Wei ZHAN Jiemin ZHAN Sheng department of civil ＆ {2. engineering The Hong Kong Polytechnic UniversityHong Kong China department of Applied Mechanics and engineering Zhongshan University Guangzhou 510275 China

The in-line response of a vertical flexibly mounted cylinder in regular and random waves is reported. Both theoretical analyses and experimental measurements have been performed. The theoretical predictions are based on the Morison equation which is solved by the incremental harmonic balance method. Experiments are then performed in a wave flume to determine the accuracy of the Morison equation in predicting the in-line response of the cylinder in regular and random waves. The interaction between waves and vibrating cylinders are investigated.

关键词： in-line response cylinder waves IHB method

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