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In order to improve the level of solid waste comprehensive utilization and reduce the cost of filling raw materials for mining, a study is carried out on the preparation of cementing agents (CA) for underground mine filling using secondary smelting water-granulated nickel slag (SWNS) as the main raw material. The mechanical properties test, X-ray diffraction (XRD), flourier transform-infrared spectroscopy (FT-IR), thermogravimetric/differential scanning calorimeter (DSC-TG), scanning electron microscope (SEM) and other test methods were used to study the working performance and mechanical properties of the cemented paste backfill (CPB) material, and the types of hydration products, micro-morphology and hydration characteristics of CA of SWNS for CPB material were analyzed. The results show that when the ratio of CA used for CPB material is SWNS:cement clink (CC):Na2SO4:flue gas desulphurization gypsum (FGDG):carbide slag (CS) = 85:2:3:5:5, the binder content on dry basis of tailings (CA/iron ore tailings (IOT)) 1:4, the slurry concentration 82%, and the addition of 0.156% PC water-reducer, the static compressive strength of CPB material 28 days is 7.94 MPa, which is 57% higher under dynamic loading conditions than that under static loading, the tensile strength is increased by 72%, and the shear strength is increased by 127%, which meets the strength requirements of CPB materials used in underground mines. CA of SWNS is a CPB material containing glass phase and crystalline materials. Under the action of various activators, it can participate in the hydration reaction, and the main hydration products are ettringite (AFt) and hydrated aluminosilicate gel material (C–M–S–H) containing Ca2+ and Mg2+; (C–M–S–H) is the main source of strength in the later stage of CPB material.

A series of single-phase Na5Y4(SiO4)4F:Eu2+,Tb3+,Eu3+ phosphors were successfully synthesized by high-temperature solid state reaction and their crystal structure and luminescence properties were investigated. The chromaticity coordinates of the as-prepared phosphors under 375 nm excitation can be tuned effectively, from the light blue (0.260, 0.213) to red (0.638, 0.337) and eventually to white (0.407, 0.373) via resonant type energy transfer and appropriate choice of color combination. Furthermore, the states occupation of the dopant ions and the energy transfer mechanisms Eu2+ → Tb3+ and Tb3+ → Eu3+ have been investigated and discussed, emphasizing on spectral content and thermal stability of Na5Y4(SiO4)4F:Eu2+,Tb3+,Eu3+ emission under 375 nm excitation. The results indicate that the Na5Y4(SiO4)4F:Eu2+,Tb3+,Eu3+ phosphors have a potential application in UV-based White LED devices.

With the increasing need of developing service life models for corrosion-induced damage in reinforced concrete structures, there has been a movement to model the concrete cover as a thick-wall cylinder subjected to an internal pressure due to corrosion products accumulation on the reinforcing steel. These models allow determining the amount of corrosion product necessary to initiate and propagate cracks along the cover. The first generation of models assume that concrete behaves linearly elastic and that the concrete cover does not have any residual tensile capacity once the tensile strength of the concrete has been reached. More advanced models include the softening behaviour of concrete beyond cracking initiation. This thesis proposes such a model wherein the state stress of the concrete cover due to accumulation of corrosion products is determined by analyzing an equivalent thick-wall cylinder subjected to a uniform internal pressure. Concrete is assumed to be an isotropic material, and deformations due to Poisson's ratio are ignored. To describe the behaviour of concrete in the softening region, a linear relation of stress versus displacement and a constant strain field are assumed. Mathematical expressions that determine the state of stress due to corrosion build-up at any point in the concrete cover are obtained by integrating the softening equations along the concrete cover. Analytical models for cracking initiation as well as longitudinal cracking of the concrete cover are formulated for both unconfined and confined conditions. The latter are the result of the presence of shear stirrups or tie/spiral reinforcement. To determine the validity of these models, their results are compared to published experimental data and finite element analyses. Finally, a parameterc analysis using the models is carried out in order to establish the role of significant model parameters on the resulting state of stress of the concrete cover and the associated damage.

Developed a the handover method and equipment of service channel based on Access and Routing Indicator in the relay network, Full consideration to relay a wireless communication networks more routing and control channel and business channel quality differences in demand, and As far as possible re-use of wireless communication networks in a variety of resources, Reduce overhead and delay of the system

Developed a control channel transmit diversity method and wireless communication network that control signaling can be transmitting by high reliability and wide coverage, the control channel is used different transmission frequency and time interval as well as the control and data is used uniform encoding and incremental redundancy code during the transmission timing interval (TTI) through joint use control channel time diversity and encoding diversity method, the control channel can be introduced time diversity gain and encoding diversity gain. And the transmission of control channel is ensured high reliability and wide coverage by the joining or Independent use of time and encoding diversity when the overhead and complexity of the system is reduced.

The ultrasonic detection is one of the important ways to inspect the wall-loss defects on-line for oil pipeline. The on-line power spectral estimation what characterized short time serial, higher resolution and anti-noise was a key technology to in-line inspect the pipeline. Based on power spectral estimation on-line, the digital multi-channels ultrasonic inspection system with 20 probes was developed. The system consists of main and sub-structure. Inspection board communicated with embedded computer with PCI bus and the numbers of channel was expended by means of high-speed switch. The ultrasonic echo signal was processed with Burg maximum entropy spectrum estimation on-line. The test shows that the inspection system could inspect the inner and outer defects and is suitable for on-line detection of pipeline corrosion. It will be used widely in practice.