铅胁迫下菲白竹的矿质营养吸收和分配

随着矿产、化工、冶金等工业排放的"三废"剧增以及汽车尾气排放量的增加,人类生存环境中的土壤、水体以及空气受重金属污染现象日趋严重,有些重金属通过食物链在人体内蓄积,严重危害人体健康(Kambhampati et al.,2003).铅是一种常见的重金属,全球每年消耗量约为400万t,但仅有1/4得到回收利用,其余大部分都以不同形式进入环境引起污染(李建正,2006).     

Analysis and Application of Creep External Uncertainty in Practice

Based on the measured data from the construction site, the prediction uncertainty of the CEB FIP MC90 due to the variation of the calculation parameters (i.e. the external uncertainty) and their sensitivity are analyzed with the help of statistical method and Latin Hypercube sampling method. Three conclusions can be deduced from the analysis. Those are a)the external uncertainty and its decreasing rate of the CEB FIP MC90 reduce with the time increasing, b)the creep coefficient increases with the increasing temperature while decreases with the increase of other calculation parameters, c)in accordance with the degrees of effect to the creep uncertainty, the first three calculation parameters are relative humidity, loading age and temperature, if the variation of the loading age is not taken into acount, the uncertainty of the creep pridection will be underestimated. Also, a method to analyze the uncertainty of the bridge structure due to the creep prediction uncertainty is proposed after the creep uncertain factor, which is the standard of the uncertainty of the creep, is introduced. An exmaple is analyzed in this paper using the random sampling method and the method presented in this paper. Through drawing a comparison between the results from different methods, the method presented in this paper appears to be feasible and efficient.     

“倒挂村”社区化管理是咋回事

2010年7月3日,北京市委书记刘淇、公安部部长孟建柱和北京市市长郭金龙等到大兴区调研社区化管理工作,提出要推行村庄社区化管理,加强社会管理创新。大生庄村、老三余村、寿保庄村……这些北京市南郊过去毫无知名度的＂流动人口倒挂村＂,在几个月前,因实行封闭式社区化管理,引起争议后再次引起人们的关注。     

Eco thinking Model of Modern Landscape Design PhilosophiesIllustrated with a Case Study of South Entrance of Tongniuling in Dalian

We discussed the trends and challenges of rapid urbanization for modern landscape from a development viewpoint. We analyzed the problems of modern landscape in P. R. China. Based on ecological principles, we proposed a corresponding eco-thinking model composing eco-thinking of vision, culture, environmental protection and public participation. We carried out a case study of the south entrance of Tongniuling Scenic Spot in Dalian. We constructed diverse scenarios according to the leading factors selected by factor analysis. We assessed them with the Delphi method and public anticipation. The priority rating was, in order, scenario number 2 (48.3%), number 1 (30.5%) and number 3 (15.7%). Scenario number 2 was the best for its prominent visual image, typical culture presentation, weaker disturbance and reasonable cost. Scenario numbers 1 and 3 took culture and environment as leading factors, respectively. The cost of the former was low while the latter was high. Our work indicates that the eco-thinking model, as a brand-new thinking for modern landscape, is feasible.     

Reliability Analysis of Initial Support in a Highway Tunnel Based on the Monte Carlo Method 

The Monte Carlo Finite Element Method is superior to other methods when it is used to analyze the reliability of the initial support of a highway tunnel. A correct reliability index could be collected when an adequate number of samples is selected because the failure probabilities of engineering structures are usually very small. The amount of sampling could sharply decrease by using the dual sampling method. During the comparison, the supporting role exaggeration of the line element, which is used in the FEM model to simulate the initial lining and rock bolt, was found by FEM simulation. The lining element reaction forces which were greater than usual were reported in FEM analysis results. Deeply Buried Tunnel Reliability Analysis was developed on the platform of ANSYS.     

Numerical simulation of solid liquid flow of Yangtze River water in a semi annulus reentry tube

The flow of Yangtze River water in a semi annulus reentry tube was numerically simulated using a Eulerian Two phase Flow Model and computational fluid dynamics. The results show that, for Reynolds number Re=28×104, silt particles with representative diameter ds=0030 3 mm are separated in reentry tubes of all curvature (R/r) sizes, while silt particles with ds=0010 2 mm separate only slightly. Silt particles with ds=0108 5 mm, which posses a strong separation effect, are separated relatively less in reentry tubes of R/r=10~40 than in tubes with other R/r sizes.     

A method for evolving the architecture and weights of neural networks via gene expression programming

An algorithm for automatic designation of the architecture and the weights of neural networks using gene expression programming (GEP) was presented. The fundamental ideas and procedures of the algorithm were discussed. The algorithm was improved to solve the problems of prematurity and lower variance rate. An application for neural networks designation was given. The experimental results indicate that the proposed GEP approach may evolve the architecture of neural network, and can obtain the weights more precisely. Compared to other conventional evolutional algorithms, GEP shows faster convergence.     

Safety Assessment of Circular Arches Tunnel Evacuation on Surrounding Geotechnical Environment

Based on the stochastic medium theory, influence on the surrounding rock and soil by tunnel excavation was studied. formula for predicting movement and deformation of rock and soil mass caused by tunnelling were deduced. And especially for the tunnel with circular arch section, half analytic solution for this problem was put forward. Furthermore, a program was developed to compute the movement and deformation of the rock and soil mass resulted from excavation. The deformation failure criterion of stochastic medium for estimating the surroundings safety was provided and was applied in an engineering example, which proved that the results of the research were reasonable and significant for the tunnel safety construction.     

‘长红2号’枣新品系的选育及栽培技术要点

‘长红2号’枣新品系由邹城市从长红枣中选出。平均单果重13．3g,含糖33．21％,每100g鲜果含维生素C576．27mg,制干率48．3％,酸枣砧嫁接苗栽植当年可结果,3年生树666．7m2产量330—374kg,9月中旬果实成熟。阐述了‘长红2号’枣的选育过程、性状表现及栽培技术要点。     

农业高等院校经管类研究生培养问题探讨

本从上海水产大学经贸学院研究生培养工作现状入手，探讨了农业高等院校中经济与管理类研究生培养和管理中存在的问题，如农业的属性对招生规模、在校学生学习行为和就业去向的影响。通过借鉴国内外知名农业大学研究生培养管理工作经验，提出农口院校经济管理类研究生培养工作中，应通过建立良好的导师队伍、营造良好的学术氛围和加强规范管理等措施和建议。本从教育模式的灵活性、专业研究方向的多样性和课程设置的科学性的角度提出一些思考。