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The spatial structure features and distributing rules of six heavy metals of antimony mining area, Cr, Cu, Ni, Zn, As, Cd and their main influence factors were researched using geostatistics combined with GIS tools. The results showed that: six kinds of heavy metal elements presented lognormal distribution. The mean of six kinds of heavy metal concentrations were higher than soil background value of Hunan province. Cd, Zn and Pb have a good correlation with each other, but the correlation between the rest elements was not obvious. The semivariogram theoretical models of six heavy metals in the study area were well fitted. The concentrations of Sb, As, Zn and Cd exhibited strong spatial autocorrelations, whereas the concentrations of Hg and Pb presented moderate spatial autocorrelations. The production activities of antimony smelter and dressing plant within the study area were the main factors for the high heavy metal concentrations of the study area.

Based on Biot’s wave propagation equation and boundary conditions, this paper builds up pile group and soil system used for calculation in 3 dimension models, though mass conservative and motion equation. The results of ground surface movement are obtained under the effect of vertical dynamic force though Newmark direct integration. Compared with the measured results, the numerical outcomes conform accurately. The calculating results show that vibration of ground surface can be affected by several parameters such as soils’ possion ratio, permeability coefficient, different types of pile groups and so on. Different factors have different effects on ground’s surface vibration in both far field and near field.

III-V channel field-effect transistors (FETs), such as metal–insulator–semiconductor high electron-mobility transistors (MIS-HEMTs), have emerged as promising candidates for future generation high-frequency, high-voltage, and high-power applications. Development of a compact model for generic HEMTs in III-V/Si co-integrated hybrid circuit design is becoming an urgent need for semiconductor industry. This paper presents device characteristics as modeled by the compact model (Xsim) for generic MIS-HEMTs. The model is based on unified regional modeling (URM) of the 2-dimensional electron gas (2DEG) charge density, including the two lowest sub-bands of the triangular well in the strong-inversion region, and extending to the moderate-inversion and subthreshold regions in a single-piece formulation. The 2DEG charge density model is adopted in the surface-potential-based current/charge model for conventional bulk/SOI/multigate MOSFETs, which makes it compatible and scalable for future III-V/Si co-integrated technologies. HEMT-specific features are also discussed, such as nonlinear source/drain access resistances, current-collapse, self-heating, parallel-channel, and quasi-ballistic effects. NRF (Natl Research Foundation, S’pore) ASTAR (Agency for Sci., Tech. and Research, S’pore) Published version

Equations based on the fictitious crack model (FCM) for a mode I crack in concrete are developed. Once the material properties—the strain softening diagram—are evaluated through experiments, the length of the fracture process zone, the fracture stress and the stress distribution ahead of the crack tip corresponding to a preformed crack at the critical state of crack growth can be solved analytically. In this way, the computational efforts associated with the application of the FCM for analysing the crack formation and propagation in concrete can be greatly reduced. The above factors stimulate the implementation of the FCM in solving practical engineering problems. Typical examples are included and variations of the length of process zone, the fracture stress and the equivalent fracture toughness with respect to the preformed crack length are thoroughly studied.