公共选修课管理系统的设计

从软件工程的角度研究了开发高校公共选修课管理系统的方法。介绍了数据库和系统逻辑模型的设计思路 ,以及系统的主要功能与主要特点。

高校公共选修课管理系统的设计

本文从软件工程的角度研究了开发高校公共选修课管理系统的方法。介绍了数据库和系统逻辑模型的设计思路，以及系统的主要功能与主要特点。

A topographical model for precipitation pattern in the Tibetan Plateau

As the highest and most extensive plateau on earth, the Tibetan Plateau has strong thermo- dynamic effect, which not only affects regional climate around the plateau but precipitation patterns of scattered meteorological also temperature and itself. However, due to stations, its spatial precipitation pattern and, especially, the mechanism behind are poorly understood. The availability of spatially consistent satellite-derived precipitation data makes it possible to get accurate precipitation pattern in the plateau, which could help quantitatively explore the effect and mechanism of mass elevation effect on precipitation pattern. This paper made full use of TMPA 3B43 V7 monthly precipitation data to track the trajectory of precipitation and identified four routes （east, southeast, south, west directions） along which moisture-laden air masses move into the plateau. We made the assumption that precipitation pattern is the result interplay of these four moisture- laden air masses transportation routes against the distances from moisture sources and the topographic barriers along the routes. To do so, we developed a multivariate linear regression model with the spatial distribution of annual mean precipitation as the dependent variable and the topographical barriers to these four moisture sources as independent variables. The result shows that our model could explain about 7o% of spatial variation of mean annual precipitation pattern in the plateau; the regression analysis also shows that the southeast moisture source （the Bay of Bengal） contributes the most （32.56%） to the rainfall pattern of the plateau; the east and the south sources have nearly the same contribution, 23.59% and 23.48%, respectively; while the west source contributes the least, only 2o.37%. The findings of this study can greatly improve our understanding of mass elevation effect on spatial precipitation pattern.

Origin of the regional stress field along the Liquine-Ofqui Fault Zone(LOFZ),Southern Chilean Andes by means of FE Simulation

The Liquine-Ofqui Fault Zone(LOFZ) of southern Chilean Andes is one of the largest active strike-slip fault zones.There is an ongoing debate regarding the origin of the stress field along the LOFZ due to its complex geometry.This paper represents a study of the origins of the LOFZ regional stress field.Stress fields are calculated by finite element(FE) analysis.The two possible stress origins, i.e., oblique plate convergence and ridge collision/indenter tectonics of Chile ridge against Peru-Chile trench, have been emphasized in the present study.Three types of boundary conditions for the three particular models have been applied to calculate stress fields.Models are assumed to be elastic and plane stress condition.Modeling results are presented in terms of four parameters, i.e., orientation of maximum horizontal stress(σ H max ), displacement vector, s train distribution, and maximum shear stress(τmax ) contour line within the model.The results of the first model with oblique plate convergence show inconsistency between the geometric shape of the LOFZ and the distribution of the four parameters.Although more realistic results are obtained from the second model with normal ridge collision, there are few coincident in the LOFZ geometry and regional stress field.The third model with normal and oblique ridge collision is reasonable in understanding the origin of stress field and geometrical condition in the lithosphere of the LOFZ.

Relationships between Landslide Types and Topographic Attributes in a Loess Catchment,China

Topographic attributes have been identified as the most important factor in controlling the initiation and distribution of shallow landslides triggered by rainfall.As a result,these landslides influence the evolution of local surface topography.In this research,an area of 2.6 km 2 loess catchment in the Huachi County was selected as the study area locating in the Chinese Loess Plateau.The landslides inventory and landslide types were mapped using global position system(GPS) and field mapping.The landslide inventory shows that these shallow landslides involve different movement types including slide,creep and fall.Meanwhile,main topographic attributes were generated based on a high resolution digital terrain model(5 m × 5 m),including aspect,slope shape,elevation,slope angle and contributing area.These maps were overlaid with the spatial distributions of total landslides and each type of landslides in a geographic information system(GIS),respectively,to assess their spatial frequency distributions and relative failure potentials related to these selected topographic attributes.The spatial analysis results revealed that there is a close relation between the topographic attributes of the postlandsliding local surface and the types of landslide movement.Meanwhile,the types of landslide movement have some obvious differences in local topographic attributes,which can influence the relative failure potential of different types of landslides.These results have practical significance to mitigate natural hazard and understandgeomorphologic process in thick loess area.

Mechanism of slope failure in loess terrains during spring thawing

Slope failure in loess terrains of Northern China during spring thawing period is closely related to the freeze-thaw cycling that surface soils inevitably experienced. Field surveys were carried out on natural and artificial slopes in thirteen surveying sites located in the Northern Shaanxi, the center of Loess Plateau, covering five characteristic topographic features including tablelands, ridges, hills, gullies and valleys. Based on the scale that is involved in freeze-thaw cycling, the induced failures can be classified into three main modes, i.e., erosion, peeling and thaw collapse, depending on both high porosity and loose cementation of loess that is easily affected. Model tests on loess slopes with gradients of 53.1°, 45.0° and 33.7° were carried out to reveal the heat transfer, water migration and deformation during slope failure. The surface morphology of slopes was photographed, with flake shaped erosion and cracks noted. For three slope models, time histories for the thermal regime exhibit three obvious cycles of freeze and thaw andthe maximum frost depth develops downwards as freeze-thaw cycling proceeds. Soil water in the unfrozen domain beneath was migrated towards the slope surface, as can be noticed from the considerable change in the unfrozen water content, almost synchronous with the variation of temperature. The displacement in both vertical and horizontal directions varies over time and three obvious cycles can be traced. The residual displacement for each cycle tends to grow and the slopes with higher gradients are more sensitive to potentially sliding during freeze-thaw cycling.

Seasonal variation and principle of cyanobacterial biomass and forms in the water source area of Chaohu City, China

We investigated seasonal variations in cyanobacterial biomass and the forms of its dominant population （M. aeruginosa） and their correlation with environmental factors in the water source area of Chaohu City, China from December 2011 to October 2012. The results show that species belonging to the phylum Cyanophyta occupied the maximum proportion of phytoplankton biomass, and that the dominant population in the water source area of Chaohu City was M. aeruginosa. The variation in cyanobacterial biomass from March to August 2012 was well fitted to the logistic growth model. The growth rate of cyanobacteria was the highest in June, and the biomass of cyanobacteria reached a maximum in August. From February to March 2012, the main form of M. aeruginosa was the single-cell form; M. aeruginosa colonies began to appear from April, and blooms appeared on the water surface in May. The maximum diameter of the colonies was recorded in July, and then gradually decreased from August. The diameter range ofM. aeruginosa colonies was 18.37-237.77μm, and most of the colonies were distributed in the range 20-200μm, comprising 95.5% of the total number of samples. Temperature and photosynthetically active radiation may be the most important factors that influenced the annual variation in M. aeruginosa biomass and forms. The suitable temperature for cyanobaeterial growth was in the range of 15-30℃. In natural water bodies, photosynthetically active radiation had a significant positive influence on the colonial diameter of M. aeruginosa （P〈0.01）.

徽戏〈十八板〉句幅原形考析

徽戏约于明末清初由“(青)阳腔”衍生而出的声腔剧种,前身谓“徽池雅调”。这种(青)阳腔在其产地唯见于(戈)阳腔目连戏中有〈十八板〉之名实的定式,是青阳腔早期(戈)阳腔滚唱中的一种腔板。因为,滚唱一般是以鼓板助节的,初时较为严格而稳定的。至于有名无实,或出现变化,可能是后期传承中的事。如:出自传学人的某一方口耳之误,或是由于弋(高)腔系统诸腔本属“随乡入俗”的民间歌唱,可“改调歌之”、“自由入曲”的随意性,一时难以心习。因而,

软件产品的质量控制

从软件产品的质量特性出发，运用软件工程理论，对软件生存期的瀑布模型、快速原形模型、运行模型和基于知识的模型进行了对比分析，提出了在软件生存期的各个阶段所应采取的质量控制方法，强调在计算机软件产品的开发过程中要以软件工程为理论依据，加强对软件产品的质量控制。

Morphological Evolution of a Void under Thermal and Mechanical Loads

A model for the morphological evolution of a void under thermal and mechanical loads is established, and the thermodynamics potential of the model is given based on energy principle. Thus, the path and the bifurcation condition of the morphological evolution of the void are described, which gives some insight into the reliability of the interconnect under combined thermal and mechanical loads.

Modelling of grain boundary impurity segregation during high temperature plastic deformation

A modified theoretical model is proposed to predict the grain boundary segregation of impurity atoms during high temperature plastic deformation. The model is based on the supersaturated vacancy-impurity complex created by plastic deformation and involves quasi-thermodynamics and kinetics. Model predictions are made for phosphorus grain boundary segregation during plastic deformation in ferrite steel. The results reveal that phosphorus segregates at grain boundaries during plastic deformation. At a given temperature, under a certain strain rate the segregation increases with increasing deformation amount until reaching a steady value, and at the same deformation amount it increases with increasing strain rate. The predicted results are compared with the available experimental values, indicating that there is a reasonable agreement between the theoretical predictions and the experimental observations.