Search

Both basalt fiber and mineral glass are water insulation materials, which are used to improve the permeability of engineered wood composite panels in this study. The contents of water resistant agent in wood composite panels are 0%,5%,10%,15%,20%,25%, respectively. It was found that the minimum thickness swelling was 2.55%, when the mineral glass content was 15%; the minimum thickness swelling was 5.09%, when the basalt fiber content was 5%. Both water insulation materials can reduce the water absorption, but mineral glass powder is more powerful.

As the low economic value, many available chemical and physical properties of coarse tail coal-slime used to be ignored. In this paper, coarse tail coal-slime is used as the filer medium for the treatment of circulating water in coal preparation plants. Because coarse tail coal-slime has great adsorption performance, appropriate particle size composition and mechanical strength, it is used as filter medium for pressure feeding filtering equipment in this study, to probe the feasibility of the treatment of circulating water. The results show that with using coarse tail coal-slime as filter medium in pressure feeding filtering tank, the concentration of circulating water can be reduced to below 5 g/L, it will meet the requirements; the particle size and thickness of coarse tail coal-slime have great influence on the capacity and concentration. This method does not need settlement reagents, and it makes full use of coal preparation plant waste.

Flicker envelope tracking is the key of analyzing voltage flicker signal. A novel method, i.e., cubic spline interpolation method is applied in the detection of the voltage flicker envelope. The typical flicker signals, such as one or multi-frequencies and frequency time-varying flicker signal are selected and analyzed by this method. Simulation results indicate that this method is effective in the detection of the envelope of voltage flicker signal. Results of one or multi-frequencies flicker signal simulation show that, when flicker frequency is less than 15Hz , the error of this method is quite tiny. The detection precision of this method is higher, especially in the scope of low frequencies of flicker and this method makes up for the disadvantage of square demodulation. Furthermore, results of frequency time-varying flicker signal simulation show that, the occurrence and recover time of voltage flicker signal can be accurately detected by cubic spline interpolation method.

The linear regression method which will be influenced by fluctuations could only calculate constant background harmonic voltage. To make up the limitation, this paper studies partial linear method. The method expands fluctuant background harmonic voltage at a time in accordance with Taylor series. On the basis of least sum of square error, the objective function selected by the method considers the influence of weight and uses bandwidth control each size of weight. This method can calculate fluctuant background harmonic voltage accurately. A case study based on the IEEE 14-bus test system is conducted and the results indicate that fluctuant background harmonic voltage can be obtained effectively and accurately by the proposed method.

In present study, the mechanical properties of disc-spring vibration isolator with viscous dampers is investigated by finite element analysis (FEA) and experiments. The result of FEA and static test reveals that frictional damping has significant effect on the static stiffness of combination vibration isolator, the ability to strengthen loading stiffness and lower unloading stiffness. However viscous damper has no effect on the static mechanical properties. The dynamic experiment shows that the dynamic performance of combination vibration isolator can be greatly improved with viscous dampers. Viscous dampers have little effect on dynamic stiffness of vibration isolator, but significant effect on damping characteristics. These conclusions are of significant importance in the analysis and design of combination disc-spring vibration isolators.

Hybrid knowledge representation schemes, including production rules, object-oriented programming, and procedural methods, are employed to express expert heuristics and standard emergency knowledge during the development of the knowledge-based system (KBS) for emergency decision for disaster reduction. This approach renders it possible to take advantages of the characteristics of each method. The system can provide the user with advice on Preliminary plan evaluation, Plan optimization, Plan evaluation ,Plan summary and Miscellaneous.

In view of the present situation of harmonic management in our country at present, put forward the new ideas of current harmonic flexible management. First on the behavior of harmonic pollution analyzed by harmonic pollution, behavior is a kind of external diseconomy activities, and to this kind of behavior is discussed, the method of internal external diseconomy activities of power harmonic pollution emission behavior of collection of sewage charges corresponding. Secondly, the harmonic pollution emissions trading, and the transaction is the social cost analysis, obtained by using the harmonic pollution emissions trading can make the ratio of sewage costs simply implement uniform standards to be low, the social effect can be more optimization. Implementation of the harmonic pollution discharge fee and harmonic pollution emissions trading can make power users to achieve profit optimization and take the initiative to improve power quality.

This paper uses Multi-index to assess regional power quality comprehensively. This paper introduces genetic projection pursuit method on power quality comprehensive evaluation. Without human intervention, this method overcomes the traditional power quality comprehensive evaluation method is influenced by subjective factors. Based on this, we put forward improved genetic projection pursuit algorithm. In the process of projection pursuit model and in the field data, changing the maximum normalized to normalization of national standard limit. According to the field experiment data in QingHai province, we assess the results by analysis and comparison with the original method. The improved method is more accurate on power quality comprehensive assessment.

Chopped basalt fibers untreated and treated by silane coupling agent were used to modify cement sample, in order to reduce water absorption. After fully soaked in water, the water content went up with the increase of fiber content. When the fiber content was 2.5Kg.m-3, the water absorption ratios of the samples reinforced by fibers without and with silane treatment were 4.83% and 5.44%, which were 57.1% and 39.5% less than the control group. This indicates that the fiber content was significant to water sorption and the influence of silane treatment is unnecessary for the reduction of water sorption.

Aiming at the superfluous force existing in the electric load simulator which can influence the load precision, the text researches the method to improve the control performance of the load system. The work principle of the electric load simulator was introduced, and building the control model of the load system based on, the whole electric load simulator control model was built. It designs feed forward compensation control algorithm. The simulation results proved that the method can solve the interference problem caused by superfluous force in theoretically.

Ni-based TiN-TiC composite coating was fabricated on DZ125 superalloy surface by laser cladding. The phase constitution and microstructures were investigated by means of X-ray diffraction (XRD), optical microscope (OM) and scanning electron microscope (SEM). Microhardness measurements and wear experiments without lubrication were also accomplished. The experimental results showed that a pore- and crack-free coating with metallurgical bonding to the substrate was obtained. Solidification morphologies along the section of the coating varied from directional dendrite in the interface to random dendrite in the surface. The coating was mainly composed of γ-Ni, M23C6, TiN, TiC particles and a small amount of NiTi, respectively. The average microhardness of 705HK for the coating was 2.3 times higher than that of the substrate. Wear tests indicated that wear resistance of the coating was significantly improved compared with that of the substrate. The improvement in hardness and wear resistance was attributed to TiN and TiC phase and chromium carbide uniformly dispersed in the matrix of the Ni-based TiN-TiC composite coating.

This study is focused on the temperature field distribution of the connecting rod. The temperature field and the time for reaching thermal equilibrium condition of the rod in a certain working environment are examined by means of finite element analysis (FEA). A verification experiment is implemented on the connecting rod. Comparison between our experiment and simulation shows that simulation values are in good agreement with experimental data. Findings from the study are supposed to provide a basis for reduction of the thermal deformation of rod as well as for improvement of the thermal characteristics and precision of high speed press.

A novel multilayered flower-like structure of BiOBr was fabricated by mild and facile polyvinylpyrrolidone (PVP) K30-assisted hydrothermal method using stable, less toxic inorganic salts Bi(NO3)3•5H2O and NaBr as the starting materials. Such three-dimensional (3D) BiOBr assemblies were constructed layer-by-layer from a large number of two-dimensional (2D) nanoplates. Rhodamine B (RhB) photocatalytic degradation experiments showed that the BiOBr flowers exhibited higher visible-light photocatalytic activity than that of irregular BiOBr nanoplates. Therefore, the resulting flower-like BiOBr are very promising photocatalysts for the treatment of organic pollutants

The InVO4-based photocatalysts loaded with metal oxides (Fe2O3, CuO, NiO) were synthesized by wet impregnation method. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy(SEM), UV-vis diffuse reflectance spectroscopy(DRS). The influence of different metal oxides loading (Fe2O3, CuO, NiO) on the photocatalytic activity for photocatalytic reduction of CO2 was discussed. It is found that Fe2O3-loaded InVO4 significantly enhance the methanol yield through promoting the effective separation of photoinduced electron-hole pairs.

Based on uniaxial tensile test, the complete uniaxal tensile stress-strain curve of Reactive Powder Concrete (the steel fiber content by volume is Vf =1%, 2%) was obtained, and the fracture energy of RPC specimens with cross-section of 100mm by 100mm was calculated. The test was finished through Universal Testing Machine without any stiffness-strengthen devices. In order to solve the stress concentration problem, a self-designed uniaxial tensile test equipment was developed, and a dumbbell-shaped specimen was used in the test. The results indicate that the fracture energy of RPC increased as well as the increasing of Vf.

The plane supporting spring, the radial stiffness of which is considered as one of the most significant parameters in design process and application, is commonly used in the isolation instruments in the fields of aeronautics, astronautics, auto industry, etc. Proposed in this paper is a force-based theoretical method for computing the radial stiffness of multi-spiral supporting spring, which is obtained by solving the component force and radial displacement of each spiral line using the force and energy approaches respectively. Finite element analysis (FEA) of Archimedes spiral-plane supporting springs with 1 to 6 spiral lines is made via speedy modeling by ANSYS parameter design language (APDL). Validity of the theoretical method has been verified by comparison of its calculation results and our numerical analysis. And the relationship between the radial stiffness of plane supporting spring and the key geometrical parameters has been confirmed by our study, which can surely provide insights into the optimal design of plane supporting spring.

Composite material has extensive application in aeronautics, astronautics and other fields due to the properties of high intensity, light weight and anti-fatigue. So controlling and rapid repairing of damaged composite material has become one of the most popular research subjects. In this paper, the common composite material for aircraft is used as test-object; The light wave of 675nm transmitted by optical fiber is used as repairing light source; special repairable reagent which can be stimulated by the light is adopted, and by the light measure technology, the effect of the vibration property in the composite material is studied by light repairing after the damage of the composite material. Based on this study, the results and analysis are shown. The research result shows that this technology is feasible in the repair of composite material and offers an experimental basis on instant test and controlling for composite material.

Composites, as a type of new material with typical characteristics, has been applied in aerospace, space, buildings, bridges and many other areas. Rapid repair from damaged composites has become a hot research project. This paper proposed a technique of light repair on composites, which is often used as specimen in aerospace composites. The research has taken advantage of modern optical measurement to study the influence of light remediation on the structural bending of composites, put forth a law of deflection variation, and proven that light remediation is feasible. The result of this research has laid the foundation that light remediation can be further studied and applied in many fields.

With its variable stiffness, capability to provide friction damping by itself, and space-based adaptive performance, the disc spring, by replacing the cylindrical helical spring extensively, has found wide application in fields like aerospace, metallurgy, architecture, machinery and so on. For the nonlinear combination disc-spring vibration isolator, the mathematical model is established in this study on the basis of classical disc spring theories. The simulation results of the combination vibration isolator under simple harmonic excitation and the effects of damping ratio and different types of load on the vibration isolator are explored in depth, the findings of which help to lay a solid foundation for parameterization and serialization of the nonlinear combination disc-spring vibration isolator.