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Simulated transmission spectra for tapered fibers with no taper, one taper and two tapers in the near infrared wavelength range, calculated by Finite-Difference-Time-Domain method are currently presented. Transmission peak positions tend to shift to the shorter wavelength when the taper deformation is added to the fiber or the taper width gets narrower. The thickness sensitivity for the tapered structures with different taper thicknesses is about 2.28e-3 nm·µm−1. There is an interference structure in the electric field distribution images, which reveals in the fiber structures. The transmission spectra for the fiber without taper, one taper and two-tapered structures were simulated in near infrared wavelength by FDTD. The transmission spectra for tlated in near infrared wavelength by FDTD. The sensitivity of the fiber was about 50 nm × RIU−1and it had better refractive index detection. The tapered fiber can be applied to the bio-chemical sensors and physical deformation testing.

n order to analyze the influence rule of water pipe cooling on the temperature field and thermal stress of large aqueduct structure, the finite element analysis model for FuYang River Aqueduct structure was established. The temperature field and thermal stress of the aqueduct structure were calculated. The following two cases were considered: structure with or without water pipe cooling, as well as the different beginning pouring months (May, June and July). The hydration-degree-based calculation methods of temperature and stress of concrete were adopted, and the high precision discrete simulation method of water pipe was used. The calculation results show that embedding the cooling pipe in concrete can effectively reduce the temperature difference between inside and outside of the early concrete and thermal stress, and is therefore effective to prevent concrete cracks. High accuracy of simulation and analysis can make people basically figure out the specific mechanism of concrete cracking and main factors even before construction, and determine accurately the structure crack location and the developing tendency.

The unique morphology and structure of carbon nanotubes (CNTs) keep attracting a great number of researchers to explore the novel properties of these materials. The special structure of CNTs determines its physical and chemical properties, mainly reflected in its novel electrical, mechanical properties and excellent adsorption performance. This review summarizes the adsorption properties of CNTs and their properties related to the adsorption of various heavy metal ions, organic and inorganic pollutants from large volumes of aqueous solutions. CNTs is a kind of potential environmental material. This article also put forward future opportunities for CNTs application in environmental systems.

The expression of reliability estimation method for fatigue life of machine parts was derived, and two kinds of stress cycles (reversed cycle and un-symmetric reversed cycle) were considered. An iteration method is presented and the corresponding computer program named STRENGTH-2 is developed for estimating reliable life of machine parts. The engineering application results show that the calculated results are close to experimental results. The proposed method can be convenient to carry out the fatigue reliability design for machine parts under the action of uni-axial and multi-axial loadings, and promote the popularization and application of existing anti-fatigue design method. It has the high value of engineering application.

By use of finite element method, the axial stresses of crossbars on the top of a simply supported rectangular-sectioned aqueduct were calculated in this paper. Three factors were considered, namely height-width ratio, water depth and crossbars spacing. The results show that, most crossbars are in compression when the height-width ratio of aqueduct cross-section is small, and with the height-width ratio increasing, the axial forces of crossbars change from compression to tension; Under a certain height-width ratio, when water depth is relatively small, most crossbars are in compression, and with the increase of water depth, axial forces of crossbars change from compression to tension; big axial tensile force is harmful to the rectangular cross-section floor (mid-span), but favorable to the side wall bottom. The obtained change rules of axial force and the influence of axial force on aqueduct body stress can be referenced to aqueduct design.

A practical technique for generating hexahedral meshes automatically is proposed in this paper. The technique is accomplished by secondary subdivision of a tetrahedron. The implementation method from tetrahedron to hexahedron through secondary subdivision is discussed. The method and treatment of boundary condition formula are derived, and the simple and practical load processing method is given. Finally a tetrahedron-based hexahedron automatic meshing program is developed. Engineering examples shows that the calculation accuracy of the method is comparatively high. The proposed method can be applied to any entity.