基于边缘效应的滨水区城市设计方法初探——以万州江南新区滨江地段城市设计为例

传统城市滨水区的设计往往较易忽略边缘区整治、功能单元间的相容性、边缘区景观带的联系作用,由此滋生出边缘负效应作用下的"边角空间",导致城市活力丧失。从"边缘效应"的角度重新审视城市设计,提出按照"提取—疏导—解构—延展—整合"的步骤建立"网—块"边缘空间结构的城市设计方法。以万州江南新区滨江地段城市设计为例,藉此方法强化和提升该地段滨水空间的边缘正效应,以期实现该区域滨水空间品质效应的增值。

Design of motion control system of pipeline detection AUV

A great number of pipelines in China are in unsatisfactory condition and faced with problems of corrosion and cracking,but there are very few approaches for underwater pipeline detection.Pipeline detection autonomous underwater vehicle(PDAUV) is hereby designed to solve these problems when working with advanced optical,acoustical and electrical sensors for underwater pipeline detection.PDAUV is a test bed that not only examines the logical rationality of the program,effectiveness of the hardware architecture,accuracy of the software interface protocol as well as the reliability and stability of the control system but also verifies the effectiveness of the control system in tank experiments and sea trials.The motion control system of PDAUV,including both the hardware and software architectures,is introduced in this work.The software module and information flow of the motion control system of PDAUV and a novel neural network-based control(NNC) are also covered.Besides,a real-time identification method based on neural network is used to realize system identification.The tank experiments and sea trials are carried out to verify the feasibility and capability of PDAUV control system to complete underwater pipeline detection task.

Numerical simulation on conjugate heat transfer of turbine cascade

Numerical simulation on conjugate heat transfer of an internal cooled turbine vane was carried out. Numerical techniques employed included the third-order accuracy TVD scheme, multi-block structured grids and the technique of arbitrary curved mesh. Comparison between results of commercial CFD codes with several turbulence models and those of this code shows that it is incorrect of commercial CFD codes to predict the thermal boundary layer with traditional turbulence models, and that turbulence models considering transition lead to more accurate heat transfer in thermal boundary layer with some reliability and deficiency yet. The results of this code are close to those of CFX with transition model.

The Construction of Applied Writing Training Network System

This document explains and demonstrates how to construct the applied writing training in network system. This system which is used in network consists of four modules, including task module, structure training module, text training module and study evaluation module. With the advantages of instantaneity, interactivity, authenticity and adequation of learning resources, the applied writing abilities of the students can be improved effectively by using the network system. And the problems during the process of applied writing teaching, for example, the teaching contents lose contract with social life, the textbook contents are lack of innovation, and writing training goes against cognizing system, can be solved effectively.

AtGGM2014, an Arabidopsis gene co-expression network for functional studies

Gene co-expression networks provide an important tool for systems biology studies. Using microarray data from the Array Express database, we constructed an Arabidopsis gene co-expression network, termed At GGM2014, based on the graphical Gaussian model, which contains 102,644 co-expression gene pairs among 18,068 genes. The network was grouped into 622 gene co-expression modules. These modules function in diverse house-keeping, cell cycle, development, hormone response, metabolism, and stress response pathways. We developed a tool to facilitate easy visualization of the expression patterns of these modules either in a tissue context or their regulation under different treatment conditions. The results indicate that at least six modules with tissue-specific expression pattern failed to record modular regulation under various stress conditions. This discrepancy could be best explained by the fact that experiments to study plant stress responses focused mainly on leaves and less on roots, and thus failed to recover specific regulation pattern in other tissues. Overall, the modular structures revealed by our network provide extensive information to generate testable hypotheses about diverse plant signaling pathways. At GGM2014 offers a constructive tool for plant systems biology studies.

Development and validation of a three-dimensional,wave-current coupled model on unstructured meshes

Using unstructured meshes provides great flexibility for modeling the flow in complex geomorphology of tidal creeks,barriers and islands,with refined grid resolution in regions of interest and not elsewhere.In this paper,an unstructured three-dimensional fully coupled wave-current model is developed.Firstly,a parallel,unstructured wave module is developed.Variations in wave properties are governed by a wave energy equation that includes wave-current interactions and dissipation representative of wave breaking.Then,the existing Finite-Volume Coastal Ocean Model(FVCOM) is modified to couple with the wave module.The couple procedure includes depth dependent wave radiation stress terms,Stokes drift,vertical transfer of wave-generated pressure transfer to the mean momentum equation,wave dissipation as a source term in the turbulence kinetic energy equation,and mean current advection and refraction of wave energy.Several applications are presented to evaluate the developed model.In particular the wind and wave-induced storm surge generated by Hurricane Katrina is investigated.The obtained results have been compared to the in situ measurements with respect to the wave heights and water level elevations revealing good accuracy of the model in reproduction of the investigated events.In a comparison to water level measurements at Dauphin Island,inclusion of the wave induced water level setup reduced the normalized root mean square error from 0.301 to 0.257 m and increased the correlation coefficient from 0.860 to 0.929.Several runs were carried out to analyze the effects of waves.The experiments show that among the processes that represent wave effects,radiation stress and wave-induced surface stress are more important than wave-induced bottom stress in affecting the water level.The Hurricane Katrina simulations showed the importance of the inclusion of the wave effects for the hindcast of the water levels during the storm surge.

Numerical method of static aeroelastic correction and jig-shape design for large airliners

In this paper,a coupled CFD-CSD method based on N-S equations is described for static aeroelastic correction and jig-shape design of large airliners.The wing structural flexibility matrix is analyzed by a finite element method with a double-beam model.The viscous multi-block structured grid is used in aerodynamic calculations.Flexibility matrix interpolation is fulfilled by use of a surface spline method.The load distributions on wing surface are evaluated by solving N-S equations with a parallel algorithm.A flexibility approach is employed to calculate the structural deformations.By successive iterations between steady aerodynamic forces and structural deformations,a coupled CFD-CSD method is achieved for the static aeroelastic correction and jig-shape design of a large airliner.The present method is applied to the static aeroelastic analysis and jig-shape design for a typical large airliner with engine nacelle and winglet.The numerical results indicate that calculations of static aeroelastic correction should employ tightly coupled CFD-CSD iterations,and that on a given cruise shape only one round of iterative design is needed to obtain the jig-shape meeting design requirements.

Mechanism,condition and characteristics for the formation of the network structure in Zr-Al-Ni-Cu bulk metallic glasses

Mechanism,condition and characteristics for the formation of the network structure in a group of Zr-Al-Ni-Cu bulk metallic glasses(BMGs) were investigated.The results show that the constituent segregation and/or the symplastic growth would be the mechanisms for the formation of the cell structure in the present Zr-Al-Ni-Cu BMGs.The cell structure can be easily obtained for the glass forming alloys whose compositions locate nearby the eutectic point.The shorter the distance is from the eutectic point,the larger the cell and the thicker the cell wall of the network structure will be.The present investigation would provide useful information for the development of the BMG with the network structure.

A large-scale wave-current coupled module with wave diffraction effect on unstructured meshes

Based on the extended mild-slope equation,a large-scale wave module is developed.By combining the eikonal equation and the modified wave action equation,the wave model can account for diffraction in most situations such as in the lee of islands and breakwaters,and using unstructured meshes provides great flexibility for modelling the wave in the complex geomorphology of barriers and islands,also allowing for refinement of the grid resolution within computationally important domains.The numerical implementation of the module is based on the explicit second-order upwind finite-volume schemes in geographic space,the Flux-Corrected Transport(FCT)algorithm in frequency space and the implicit Crank-Nicolson method in directional space.The three-dimensional hydrodynamic module is then modified to couple with the wave model,where the wave readily provides the depth-dependent radiation stress and the wave-induced turbulence coefficient for the current fields,and the wave propagation takes into account the current-induced advection,refraction and diffraction of wave energy and the effect of water level.The applicability of the proposed model to calculate Snell’s Law,wave transformation over the breakwaters and the elliptic shoal,wave propagation over the rip current field and the undertow on a sloping beach is evaluated.Numerical results show that the present model makes better predictions of the near-shore wave propagation and complex three-dimensional(3D)near-shore circulation driven by the waves,considering analytical solutions and experimental values.

The assembly of plant-patch networks in Mediterranean alpine grasslands

Aims Harsh environmental conditions in alpine ecosystems shape vegetation structure into patches,where many different plant species cluster and grow together.Yet,which factors are important for the structure and dynamics of such plant–patch networks remains poorly understood.We aim to assess which and how environmental and biotic factors predict the assembly of plant–patch networks along a mountain range.Methods We examined the distribution of plant species in more than 5500 vegetation patches in 37 Mediterranean alpine grasslands distributed along a 500 m altitudinal gradient(National Park of Sierra Guadarrama,Spain).We established a plant–patch network for each grassland community and analyzed how nestedness and modularity vary with environmental(altitude,insolation and soil conditions)and biotic factors(number of species per plot,mean patch area and total pasture area).Important Findings Plant–patch networks showed consistent,non-random patterns characterized by a nested,but not modular,structure,which suggests that positive associations among co-occurring specialists promote their growth within patches as subsets of a pool with more generalist species.Both nestedness and modularity of plant–patch networks varied among grasslands.Specifically,nestedness decreased with increasing species per plot and increased with mean patch area,while it was independent of environmental variables;modularity increased with increasing pasture area and species per plot.The negative relationship between species per plot and nested patterns may be linked to the restricted number of species that can coexist within the same patch at a given size.Moreover,the positive relationship between patch size and nestedness indicates that the growth of rare plant species within vegetation patches occupied by more abundant species is facilitated in bigger rather than smaller patches.Furthermore,these results indicate that the nested assembly of vegetation patches may be independent of abiotic conditions.These findings suggest that large and unfragmented vegetation patches are fundamental for the maintenance of plant diversity in alpine grasslands.Looking at species distribution at fine spatial scales may shed new light on the biotic processes underlying plant network assembly and provide novel ways for conserving biodiversity.