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Climate change is a hot issue on the current time and snow melting process in alpine areas has be affected on the background of climate change, so it is necessary to study snow melting process especially the snowmelt model. In view of the shortcomings of the degree-day model (DDM), the double layer snow-melt model (DSMM) is improved and developed based on the original theory. Then the simulation of the snowmelt process of the upper reaches of Lancang-Mekong River is performed by the improved double layer snow-melt model (IDSMM) and DDM respectively, the simulation results are analyzed in view of model theory, snowmelt critical control conditions, the effects of the simulation and working conditions in the changing environment. The results show that IDSMM based on the energy and mass balance is superior to DDM in the snowmelt physics mechanism, and it not only can simulate the snow melting process, but also can simulate many physical processes, such as the canopy interception of snowfall, vaporization and sublimation loss in evaporation, the second precipitation from canopy surface, the process of snowmelt water freezing again and so on. The simulation results of snowmelt process is more tally with the actual situation and it can provide a reference to the research of snow and ice hydrology and the whole water cycle in a changing environment.

This work presents a broadband optical transparency structure consisting of a metal film perforated by an array of strip cavities. We theoretically demonstrate the metal film with side-coupled grooves system in model structure by the coupled model theory. The transparent light with a great bandwidth is obtained as a result of the tunneling and the resonance effect of the cavities by employing the finite-difference time-domain method simulation. By changing the parameter of the grooves in the structure, the transparency property shows a great adjustment in both wavelength and bandwidth. These structures have potential applications for transparent conductor devices.

In this paper, a channel drop filter (CDF) is composed of two cubic lattice circular ring resonator cavities and point micro-cavities in a two-dimensional photonic crystal. The photonic band gap is calculated using the plane wave expansion (PWE) method and the optical characteristics of proposed structure are studying by the finite difference time domain (FDTD) method with perfectly matched layers (PMLs) acting as the boundary conditions . Two different wavelengths centered at 1773 nm and 1742 nm have been successful separation in this CDF. These demonstrate that our proposed structure is suitable for photonic integrated circuits (PICs) and coarse wavelength division multiplexing (WDM) optical communication systems.

We propose a high tunable plasmon-induced transparency metal film structure which can be performed by double two-dimensional hexagonal lattice array of plasmonic nanoparticles inserted with a continuous metal film. The structure shows metal transparency in the optical regime. The transparency response in this structure can be efficiently modified by varying the thickness of the metal film, the size of nanoparticles, and the position of the nanoparticles. The structure proposed here may provide a new alternative approach to obtain transparent and highly conducting metal structures with potential applications in optoelectronic integrated circuits, plasmonic filters and transparent conductors.

Cu-matrix bearing materials were prepared by powder metallurgy method and their mechanical properties were studied in present work. The continuity of copper alloy matrix was destroyed with the increase of Bi element. Because Bi is brittle phase and distributed in the copper alloy matrix grain boundaries as thin ribbon network. The hardness, crushing strength and impact toughness of copper-bearing materials were reduced with increase of the content of Bi. The mainly of Copper-bearing materials containing bismuth fracture are brittle intergranular fracture. When the Bi content is over 4wt%, the Bi has a relatively full distribution in the rich Bi phase of copper alloy matrix grain boundary like a chip mesh belt. As the further increase of Bi, the reduced trends of the mechanical properties of Cu-matrix bearing materials containing bismuth are slow down. because the role of fragmented Copper alloy matrix will not significantly increase with further increase of Bi.

The corrosion resistance of chromium-free passivation film with single chromate-free passivation solution to deal with galvanized steel still has a gap compared to chromate passivation. In this experiment, the passivation solution consisting of the inorganic salt as corrosion inhibitor, silane as sealer, water-based epoxy resin and additives which formed a layer of inorganic and organic composite passivation film on galvanized steel through the synergistic effect between inorganic and organic. The morphology and elements of the passivation film was analyzed by scanning electron microscopy (SEM) and the corrosion resistance of the composite film was tested by neutral salt spray test (NSS), lead acetate spot test (ASS), tafel polarization curves and AC impedance spectroscopy (EIS). The results show that the composite film has a good adhesion and an excellent corrosion resistance, the corrosion area is only 3% after 72h NSS.

In this paper, ANSYS/LSDYNA software is used to simulate the process of armor-piercing projectile vertical penetrate metal matrix functionally graded material (FGM) armor reinforced by ceramic particles with the distribution of two power-law function along the thickness direction. The ceramic particle volume fraction varies from layer to layer along the armor thickness while ceramic particles total volume fraction remains unchanged. Four different ceramic particles distribution armors with the same total volume fraction are simulated. And the effects of the two power-law function types on the penetration of functionally graded material armor are investigated. The results show that the ballistic resistance of ceramic particle reinforced functionally graded armors is better than homogeneous ceramic particle reinforced armor with the same total volume fraction. Meanwhile, the larger the ceramic particles volume fraction on target surface is, the better ballistic resistance of functionally graded armors will be.

The article has analyzed the changes of temperature of different materials of the spindle, and considered 170SD30 Ceramic Motorized Spindle and the same model Metal Motorized Spindle as the research objects, analyzed the inside heat source and heat transfer mechanism of the high-speed motorized spindle; used finite element software to set up the model of the motorized spindle, and did simulation and analysis. Verified by simulation, heat transfer rate of ceramic materials is slower than the metallic materials, in actual operation of the process, due to different materials have different heat transfer rate, so the temperature distribution of the different materials of motorized spindle are different. This conclusion provides the basis to solve motorized spindle temperature field distribution.

There exist evident shear-lag phenomena in large-span composite cable-stayed bridges under the action of axial force, especially in the deck with double main girders. In order to discuss the distribution law of the effective flange width coefficient along the span, caused by axial force, finite element computations of five composite cable-stayed bridges and theoretical analysis have been performed. The transmission angle of axial force caused by the axial compression of stay cables was given, meanwhile the formulas for computation effective slab width coefficient under axial force were suggested.

Nitrogen deposition input changes the carbon and nitrogen cycle rate significantly in terrestrial ecosystem, and then affects the structure and function of entire ecosystem. The elevated atmospheric concentration of greenhouse gases is one of the most important causes of global warming and has become an indisputable fact. Terrestrial ecosystem is the important source and sink of greenhouse gases, and plays an extremely important role in global warming. Nitrogen deposition can affect the fluxes of greenhouse gases from terrestrial ecosystem. The responses of greenhouse gases emissions to nitrogen deposition in forest ecosystem, farmland ecosystem, grassland ecosystem and wetland ecosystem of typical terrestrial ecosystem are reviewed in this paper. As a result of the differences of ecosystem types, climate, vegetational community and soil N status, the effect of nitrogen deposition on main greenhouse gases flux emissions present in three aspects: suppression, promotion and non-significant in terrestrial ecosystem.

This paper presents a new approach to thermal field sensitivities and ampacity computations of underground power cables using a proposed algorithm of perturbed finite-element analysis. Domain-specific visual language tools have become important in many domains of software engineering and end user development. Numerical results show that the most significant randomness comes from thermal loads and also that the amount of uncertainty decreases from input to output. We will show that the object-oriented programming greatly simplifies the choice and the implementation of other formalisms concerning polyarticulated systems, thus conferring high flexibility and adaptability to the developed software.Such experimental verification confirmed the accuracy of the new introduced finite-element sensitivity methodology.

Both transient-state and steady-state interfacial tension (IFT) between anion Gemini surfactants solution and crude oil were measured. The effects of various parameters such as anion Gemini surfactant molecular structure, concentration, category of crude oil and salinity of water medium on the interfacial tension between crude oil and water were investigated in detail. The results reveal that when the length of the carbon chain or the carbon number of spacer is constants, the increase of either carbon number of interval groups or length of carbon chain is favorable to decrease the interfacial tension. AN12-4-12 has the lowest interfacial tension. As the concentration of anion Gemini surfactant increasing, the interfacial tension between crude oil and water decreases. Anion Gemini surfactants which have a larger carbon number of interval group and longer hydrophobic carbon chain have a better interfacial activity. AN12-4-12 has the best interfacial activity. When the concentration of AN10-4-10, AN12-4-12 reaches up to 2000 mg•L-1, it can lower the steady-state oil-water IFT to 10-3mN•m-1. Different kinds of crude oil have different effects of decreasing IFT and different interfacial activity for the same anion Gemini surfactant. The Critical Micelle Concentration (352mg•L-1, 487mg•L-1) of AN8-4-8 and AN12-4-12 between thin oil and water interface is obviously lower than those (1000mg•L-1, 3000mg•L-1) between mixed heavy oil and water interface. But molecular structure still has a larger influence on interfacial tension than category of crude oil. The IFT between AN12-4-12 solutions and mixed heavy oil lower an order of magnitude than that between AN8-4-8 solutions and mixed heavy oil. As the solution salinity increased, the interfacial tension between anion Gemini surfactant solution and thin oil decrease rapidly. The longer the hydrophobic carbon chain is, the more obvious the effect of salinity is. The salinity is not less than 1.2×105mg•L-1, AN12-4-12 can decrease the oil-water interfacial tension to 2.2×10-3mN•m-1, while AN8-4-8 only makes that reduce to 9.7×10-3mN•m-1.

Based on the SIMULINK tool of MATLAB, the paper researches the ship power system, the research includes: load suddenly increased or decreased when one single generator is running, generators’ running in parallel, load suddenly increased or decreased when two generators are running in parallel. Through the analysis of the different work condition, the paper researches the transient stability of the ship power system.

The oil-water interfacial tension measurement and enhancing water displacement recovery experiment were carried out, and the effects of various parameters such as category of surfactants, anionic Gemini surfactant concentration, water medium salinity, core permeability, polymer and non-ionic surfactant on anionic Gemini surfactants enhancing water displacement recovery were investigated in detail. The results show that surfactants category is different, its enhancing water flooding recovery efficiency is different, and effect of enhanced oil recovery is consistent with surfactant ability to reduce oil-water interfacial tension. The anionic Gemini surfactant AN12-4-12 is the best in enhancing water flooding recovery efficiency, because it can reduce the oil-water interfacial tension to 5×10-3 mN•m-1. Increasing the concentration of AN12-4-12 is favorable to enhance water displacement recovery. Such as when injecting 0.5PV solution containing 800mg•L-1 AN12-4-12, enhancing water displacement recovery is 11.67%. AN12-4-12 has good adaptability to different salinities (5~25×104 mg•L-1) and low permeability reservoir in improving water displacement recovery. Adding non-ionic surfactant ANT into AN12-4-12 solution can further reduce oil-water interfacial tension and enhance water flooding recovery efficiency. For example, injecting 0.5PV surfactant solution containing 400mg•L-1 AN12-4-12 and 100mg•L-1 can enhance water displacement recovery of 10.7%.

This document analyses the surface of piston in two aspects, discrete points of axial section profile are fitted by cubic spline tool of MATLAB, interpolate curve after fitting with method of precision linear approximation. Equipartition of cross section profile are done,and through subdivision of points of equipartition,to approach theory contour. the number of divide points must satisfy the request was made, with the principle of the relative movement，in the processing of cross section in an ellipse，detailed analysis the motion of line motor，pointed out how changes the speed and acceleration of workbench.and must satisfy the basic conditions of the line motor to respond to the turning of cross section in an ellipse. On this basis, design a lathe machining CNC system of piston with structure of upper and lower computer, moulding of surface of piston are completed by upper computer, feed drive of X, Z axis and spindle are completed by lower computer, surface of middle-convex and varying piston are processed finally.

Ceramic insulating tile is the main insulation material used on space shuttle thermal protection system at present, but this material has low strength, high brittleness and easy to be damaged. So the study of thermodynamic response of damaged rigid ceramic insulating tiles is very important. In this paper the temperature field and thermal stress field of the damaged ceramic insulating tiles under aerodynamic heating are simulated by ABAQUS code. The analyzed results indicate that the sharp degree of the damage shape has minor influence on the temperature field, but is more significant for the maximum thermal stress. Meanwhile the larger loading is, the bigger influence is.

Based on theory and semi-empirical formula, this paper uses the method of reference enthalpy to calculate the surface aerodynamic heating flux of waverider with sharp leading edge. On this basis, applying ultra high temperature ceramic materials ZrB2–SiC, thermal response of the sharp leading edge is studied. The results show that the aerodynamic heating can make thermal stress intensity extremum inside the structure exceed the ultimate strength of material quickly. Though the temperature inside the structure is much lower than material heat-resistant temperature extremes, thermal stress shock is able to cause material to damage in a very short time.

In this paper, a new type steel plate with nano-layered martensite lath structure was produced by heavy cold-rolling. After rolling, subsequent annealing has great effect on the deformed martensite morphology and grain refinement. Microstructure recrystallizing course have occurred after long time annealing at 350°C. The recrystallization activation energy is 151 kJmol-1. The ultrafine ferrite grains (average grain size about 317nm), nano-carbides precipitated uniformly were seen in the specimen annealed at 500 °C. Annealing at and above 600 °C resulted in coarse ferrite grains with spheroidized coarse carbides, causing grain growth.

In order to discuss the mechanical behaviour differences between the two-tower and three-tower suspension bridges, based on the Taizhou Yangtze River Bridge, three dimensional space finite element models of two-tower, three-tower with concrete mid-tower and with steel mid-tower were constructed. Through the comprehensive analysis, main conclusions are got as follows: due to the mid-tower lack of effective restraint from side cable, compared with two-tower suspension bridges, three-tower suspension bridges have lower total stiffness and natural frequency, with larger deflection-to-span ratio of main girder. So, some factors such as anti-slipping safety factor between the main cable and saddle, deflection-to-span ratio of main girder and force in mid-tower, which are not important in two-tower design, become controlling ones in three-tower suspension bridges. These factors are related to anti-pushing rigidity of mid-tower, but in contradictory demanding for the rigidity of mid-tower. After comprehensive analysis, steel tower with shape of upside-down ‘Y’ meets all demands, and then, was selected as appropriate structure for the mid-tower.

Mechanical behaviours of three-tower suspension bridges from perspective of influence line help insight into mechanical behaviour nature, and grasp the differences between two-tower and three-tower suspension bridges in Static and dynamic behaviours. Based on the Taizhou Yangtze River Bridge, three dimensional space finite element models of two-tower, three-tower with floating system and three-tower with elastic cables between mid-tower and the girder were constructed. Through analysis of influence lines characteristics of different key effects and effect envelop under vehicular load, main conclusions are got as follows: Some factors such as deflection-to-span ratio of girder, anti-slipping safety factor between the main cable and saddle of the mid-tower and force in the mid-tower, horizontal displacement at the end of girder, which are not important in two-tower design, become controlling ones in three-tower suspension bridges and effects under vehicular load is the most important. When live load acts on all or part of one main span, the four control factors reach the worst case, but in very low probability. Code restriction on deflection-to-span ratio of girder can be flexible to relax restriction to 1/220, and riding comfort is still guaranteed. Stresses of mid-tower under vehicular load plus dead load are in a state of compressive stress in the majority of operating conditions and fatigue problem is not obvious.

An ultrafine microduplex structure was successfully produced through equal channel angular pressing (ECAP) at ambient temperature. According to the morphological characteristics of cementite lamellas, the deformed pearlite consists of shear break lamella, locally thinned lamella and irregularly bent lamella. The proportion of locally thinned lamella and irregularly bent lamella has increased with the pass number of ECAP. In addition, the deformed pearlitic ferrite became a supersaturated solid solution of carbon due to the partial dissolution of cementite during ECAP.