Accomplishment of Elastic-plastic Analysis in Geotechnical FEA

In order to realize elastic-plastic analysis in geotechnical FEA, in this paper, firstly, the method how to realize elastic-plastic analysis in Super-Sap is discussed. Then, this paper stresses to introduce the principle and the steps used to achieve the accomplishment of elastic-plastic analysis in Super-Sap. Finally, an engineering practice is given to prove that the geotechnical FEA elastic-plastic analysis and visualized post-processing can come true by it rapidly.     

簕杜鹃盆景

簕杜鹃是岭南盆景主要树种之一，它叶细，枝条密，萌发力强，枝条古朴，苍劲有力。枝干生长快速，适合岭南盆景的“蓄枝截干”造型手法；适应性强，既喜阳光和水肥，又能耐旱和耐阴；花期较长，花色艳丽夺目；虫害少，枝条与叶基本上没有虫害；树桩粗生易长，新种树桩成活率常达100％。如果用一年生的木质化壮旺枝条，每段长约10—15厘米，在初春插于沙质土壤中，成活率也可达95％以上。     

Effect of cooling rate on high temperature mechanical properties of weathering steel

High temperature mechanical properties are key factors which affect fracture production during deforming process of continuous casting. High temperature properties of weathering steel Q450NQR1 are tested in 3 cooling rates (1.65, 5, 10 ℃/s) using Gleeble thermo-mechanical simulator. Specimens appear austenite dynamic recrystallization at 1 050 ℃, and the ductility reaches the lowest point and the reduction of area approaches 23% at 850 ℃ in 3 cooling rates. As the cooling rate increases, the low ductility area where cracks are easy to be produced in slabs is enlarged and extended towards low temperature, and the ductility troughs are deepened. The increase of the cooling rate decreases the tensile stress and yield stress, while when the cooling rate increases to some degree, it doesn’t affect the stress. The low cooling rate decreases the film or network ferrite producing in austenite grain boundary, and the carbonitride of microalloy is enwrapped in matrix, which is helpful to improve the ductility of steel.     

Wood thermal conductivity prediction by using support vector regression

The support vector regression (SVR) method combined with particle swarm optimization (PSO) is proposed to establish a model for predicting the thermal conductivity of timber in transverse directions (radial direction and tangential direction) based on the measuring database of thermal conductivity under different influential factors, including its density, moisture content and specific gravity. Comparing the prediction results of SVR method with those from analogism (ANA) model and BP neural network (BPNN) model, it is shown that the prediction precision is higher for SVR method by applying identical training and test samples and increase of training samples could improve the generalization ability. With the validation test by leave-one-out cross validation (LOOCV) test, maximal absolute percentage error (MPE), mean absolute error (MAE) and mean absolute percentage error(MAPE), are the smallest for the prediction of SVR method. It is suggested that SVR is an effective and powerful tool for predicting thermal conductivity of timber.     

Small scale wind tunnel for high pressure and high energy discharge

A kind of small scale wind tunnel with low velocity is proposed according to the characteristics of strong ionization discharge chamber and the demands of discharge for flux, velocity and flow fields. On the precondition that the airflow field and velocity is satisfied, aerodynamic design and structural design are carried out. Key techniques are studied including overall structure, aerodynamic and structural design of airflow vent and collection vent, aerodynamic and structural design of power section, flow rate adjustment and control, and cooling system of motor. Based on the design scheme, a small scale wind tunnel with strong ionization discharge for an enterprise is developed. Application indicates that the small scale wind tunnel is a practical and effective airflow loop device for high pressure and strong ionization discharge with the features of stability and reliability.     

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.     

榆树盆景的栽培养护

榆树(Ulmus parvifolia Jacq.)由于树干苍劲,枝条萌发力强,生长速度快,愈伤性能好,很适合岭南树桩盆景的截干蓄枝造型而大受盆栽家的喜爱,与九里香、福建茶、雀梅为岭南树桩盆景四大树种。本人栽培榆树盆景已有三十年,对榆树盆栽有如下体会,现提出来与行家们共同切磋。 1.提高榆树成活率的方法榆树每年11月底停止生长,并落叶进入休眠期,到翌年二月中旬左右开始萌发新芽,重新生长,榆树一定要在休眠期间起地     

A Numerical Study on the Damage Assessment of a Simply-supported Beam on Natural Frequencies

Based on the perturbation theory, it was proved that the ratio of changes of frequencies is the function of structural damage location. Taking a uniform cross-sectioned simply supported beam for example, the ratio of changes of frequencies between the damaged and intact beam was used to locate and qualify beam damage. For different extents of damage, the changes of frequencies and ratio of changes of frequencies were studied and the effects resulted from the omission of second order items were discussed. Finally, the deficiency of this method was pointed out.     

Experimental analysis of matrix shrinkage’s influence on mechanical permeability of gas filled coal

Based on the coal seam of Zhao zhuang coal mine and Si he coal mine belong to Jin cheng anthracite Mining Group in Shanxi province, by using the self developed three axial servo controlled seepage equipment for hot fluid solid coupling of coal containing methane, parallel experiments for permeability of helium and methane under different gas pressures are carried out to quantitatively study the influence of Klinkenberg effects on the permeability of coal. Meanwhile, the problem of permeability decreasing caused by fluid pressure decreasing and gas desorption is eliminated by controlling the effective stress. The results show thatthe Klinkenberg effect is obvious under low gas pressure. With the increase of gas pressure, the permeability of coal decreases at first and then increases. The inflection points of gas pressure for Klinkenberg effect are about 0.9 MPa both for coal samples in Zhao zhuang coal mine and Si he coal mine. When the effective stress is constant, with the increase of gas pressure, the permeability increment caused by Klinkenberg effect decreases, while permeability increment caused by coal matrix shrinkage increases. Coal matrix shrinkage has a close relationship with the mechanical properties of coal rock mass. For the coal sample with a poor mechanical property, coal matrix shrinkage is more obvious.     

Efficiency of Embodied Technology Spillovers

Technological progress is the key competitive ability of a society.A society's technological progress depends on it's ability of research and development (R&D) and the absorption of R&D spillovers. Since China is a developing country, which is comparatively short of R&D expenditure and activity, it is absolutely necessarily to utilize R&D spillovers. This paper analyses the relation among destination-specific AC (Absorption Capacity) , source- and destination-specific SS (Structural Similarity) and embodied technology spillovers by one-sector and three-areas GTAP models. The conclusion is:Being 'neutral' in nature, the exogenous Hicks-Neutral Technical Progress shock uniformly reduces the input requirements associated with producing a given level of output of stuff.