Stochastic structural model of rock and soil aggregates by continuum-based discrete element method

Ancient slope[1], debris-flow deposit[2] and rock-filling dam[3] are usually made of rock and soil aggregates (RSA). The RSA is a typical inhomogeneous and discontinuous medium, and its main characteristics include: (i) loose piling up by blocks or particles, (ii) mixing of different blocks with a range of shapes and sizes, (iii) stochastic distribu- tion of blocks in space, (4) fillings often in between blocks. The mechanical properties of these rock and soil aggregates are commonly obtaine…     

Flume Experiment on Stream Blockage by the Debris Flow From Tributary

Stream blockage by the debris flow from tributary valleys is a common phenomenon in mountainous area,which takes place when large quantities of sediment transported by debris flow reaches a river channel causing its complete or partial blockage.The dam formed by debris flow may causes upstream and downstream flooding,and presents great threat to people and property.Because of the catastrophic influence on people and property,debris-flow dam has attracted many attentions from the researchers and local administration.But,lit- tle attention has been given to the quantitative interrelationships of the potential influential factors.In this pa- per,the interrelationships of important influential factors caused the stream blockage by debris flow were ana- lyzed through flume experiment,and a model to predict the blockage was presented.     

An Investigation of Stochastic Nature of Bed Load Motion in Chuanjiang River

Bed Load Motion and its transport rate is one of the basic issues in river dynamics.In this paper, the authors discussed the stochastic nature of bed load motion in Chuanjiang River in details.Chungjiang lies in the upstream reach of Yangtze River.Its stochastic nature is shown in the following four aspects.Firstly, even though all the conditions are the same,due to the fluctuation of the flow,the bed load discharge and the location and width of sediment transport belts are different.Secondly,during the process of bed load motion, pebbles show the strong nature of intermittence.Thirdly,the sediment discharges through upstream and down- stream reach are not equal,i.e.the pebble motion exists the discontinuity.Fourthly,annual mean transport rates of bed load for different stations are different and variation of transport rate of pebbles for a given station with year is large.The four aspects will be discussed one by one detailedly.     

Water target based cross-calibration of CBERS-02 CCD camera with MODIS data

The CBERS-02, the second satellite of China Brazil Earth Resources Satellite series, was launched on Oct. 21, 2002. Onboard the satellite, there are three major sensors, a CCD camera, a wide field imager and an infrared multispectral scanner (http://www. cresda.com). The purpose of this paper is to calibrate the CCD camera with a methodol- ogy of cross-calibration. The spatial resolution of the multispectal bands of CCD camera is 19.5 m, the swath is about 115 km. It is capable of side…     

Estimation of the resident’s additional dose in bone-coal mining areas of the five provinces

1 Introduction In the National Investigation of Natural Radioac-tive Levels (abbreviated as “investigation of levels” hereinbelow) during 1983 to 1990, it is found that the specific activities of radionuclides in bone-coal are relatively high. The increase of radioactive level in the environment and the rise of the public accepted dose might be caused by some artificial activities, which include mainly mining and utilizing spontaneously bone-coal by local peasants, producing bone-coal cind…     

商业企业决策支持系统方案设计

决策支持系统作为一种新兴的信息技术,能够为企业提供各种决策信息以及许多商业问题的解决方案,从而减轻了管理者从事低层次信息处理和分析的负担,使得他们专注于最需要决策智慧和经验的工作,因此提高了决策的质量和效率。文中对决策支持系统在商业企业中的运用作了一些探讨。     

Preparation and Photolunlinescence of Ordered ZnO Nanowire Arrays

Ordered ZnO nanowire arrays embedded in anodic aluminum oxide (AAO) membranes were fabricated by electrochemical deposition of Zn(NO3)2+H3BO3 solution in a boiling bath. Scanning electron microscope (SEM) and transmission electron microscope (TEM) observation results show that the polycrystalline ZnO nanowires with diameters around 100 nm were uniformly assembled into the ordered nanochannels of the AAO. The results of the investigation into photoluminescence (PL) and electronic paramagnetic resonance (EPR) measurements reveal that the interfaces between the ZnO nanowires and the pore walls of the AAO create a lot of oxygen vacancies, which are responsible for the green light emission (peaking around 512 nm) and the huge enhancement of the PL emission.     

Solution of a hollow thick-wall cylinder subject to quadric function pressures and its limit when l→∞

Analytical solution of basic equations in any discipline, especially in engineering science, is important. The solution of a hollow thick-wall cylinder subject to variable pressures, which is in fact a solution to the spatial symmetric problem, has found wide applications[1]. But the pressure is not always distributed uniformly in engineering prac-tice. So it is very significant to get the solution of arbitrarily distributed pressures. Among various functions, the multinomial function is most …     

Influence of stresses on martensitic transformation in ferromagnetic shape memory Ni_(50)Mn_(19)Fe_6Ga_(25) ribbons

~~Influence of stresses on martensitic transformation in ferromagnetic shape memory Ni_(50)Mn_(19)Fe_6Ga_(25) ribbons1. Ullakko, K., Huang, J. K., O'Handley, R. C. et al., Large magnetic-field-induced strains in Ni2MnGa single crystals, Appl. Phys. Lett., 1996, 69(13): 1966-1968. 2. James, R. D., Wuttig, M., Magnetostriciton of martensite, Philos. Mag., 1998, A 77: 1273-1275. 3. Wu, G. H., Yu, C. H., Meng, L. Q. et al., Giant magnetic-field-induced strains in H…