Abstract: In the interest of improving the curing effect and mechanical properties of pultruded carbon/glass bybrid fiber composites, the DSC (Differential Scanning Calorimetry) technology was introduced and the curing DSC curves for the hybrid fiber composites at 4 different heating rates was attained. Then the range of the processing temperature for the three-stage heating pultrusion was primarily determined with T-β method. Subsequently a kind of carbon/glass hybrid composite pole with a diameter of 11mm was selected as the research object, and was manufactured with varies of processing temperatures and speeds. The produced poles were mechanically tested to investigate the effect of processing parameters on the mechanical properties of the composite, so as to further more ascertain the processing parameter ranges fitting to this material formula. As the result shows: the pultrusion processing parameters for the hybrid fiber composite acquired in this study can satisfy the require of manufacturing; compared with the traditional method that attain processing parameters by experience, the method for attaining processing parameters suggested in this paper is more efficiency, more economical and more accurate.
Abstract: 2-hydroxy-4-glycidyl ether benzophenone(HGEBP) is synthesized with 2,4-dihydoxy- benzophenone(UV-0) and epichlorohydrin(ECH) as starting material, then a series of chitosan (CS) based novel ultraviolet absorbers (CS-g-UV-0) are synthesized by the reaction of chitosan with HGEBP in isopropylcarbinol in the presence of sodium hydroxide. The products(CS-g-UV-0) are characterized by means of Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), and UV spectrophotometer. The results of UV absorption show that anyone of the grafted products has a strong ultraviolet absorption area ranging from 280nm to 350nm and the maximum absorption peak presents at 291 nm. It is found that the grafted products could improve the moisture-absorption and moisture-retention property with the increase of G% values.
Abstract: The paper addresses the assessment of the steam-side oxidation behavior of alloy TP347H tubes in supercritical boilers.The high temperature heating surface of supercritical boiler can easily form the oxide scale on the inside surfaces of steam tubes after a period of operation. When accumulated to a certain amount, the oxide scale would exfoliate. It could influence the actuating medium flowing and heat transferring, cause overheating or even the explosion of heating surface. The oxide scale sampled on heat-absorbing surface of alloy TP347H tubes was examined. The oxide exfoliation sampled was studied experimentally by energy dispersive spectrometer and the X-ray diffractometer. The constituent elements and structural features of oxide scale in TP347H tubes were emphatically analyzed. The mechanism of steam-side oxidation and scale exfoliation in the TP347H tubes, as well as its influence factor, were described. It is found that the temperature is one of the most important influences. The measures that controlled the oxide exfoliation on a large scale were brought forward so as to provide a scientific guidance for reducing the oxide scale formation and avoiding tube bursting for over-temperature.
Abstract: This paper presents the thermal-mechanical coupled model of polycrystalline aggregates based on plastic slip theory inside crystals and on the interfaces of crystals. It involves the mechanics and heat conduction behaviors caused by both force loads and temperature changing in the polycrystalline aggregates. At first, the constitutive relationship inside single crystal, and the moment equations and energy equations are derived by means of rate-dependent plastic deformation theory and the formulas of elastic-plastic tangent modulus depended on temperature. And those on crystal interfaces are also given. Based on the ABAQUS software , the subroutines to calculate the tension, torsion and bending strength of polycrystalline copper are coded. The numerical simulation results show that breakages occurred more easily on the interfaces than other areas of the polycrystalline aggregates, especially for bending loading and torsion loading, and that’s consistent with results by molecular dynamics but their computing cost are less and less than MD simulation.
Abstract: Structure, viscosity and crystallization behavior of CaO-MgO-SiO2 ceramic fiber with Nd2O3 were investigated by DTA, XRD and FTIR techniques. The results show that the addition of Nd2O3 enhanced the fiberization by extending the viscosity curve of the glass melt to lower temperature and improved the melt fiberizability. With the reinforcement of silicate glass network by Nd3+, the precipitation of crystals in fibers was inhibited at high temperatures.
Abstract: The construction management maturity model for the proceeding constuction is mainly studied in this paper. As one of the methods of construction management of project, the construction management maturity model can not only be used for evaluating of the construction management ability but also assess the current construction management level of engineering indusdtries to find the gap and provide the approaches of continuous improvement for engineeringl enterprises. In the paper, the characteristics of construction management maturity model of engineering enterprises are first introduced, and then some international construction management maturity models widely applied are compared. Based on the above, the present situation of application of the construction management maturity model in the engineering industries of China and some main problems needed to be resolved for establishment of the construction management maturity model suitable to the architectural enterprises of our country are finally pointed out.
Abstract: This paper adopts the finite element method to study the shear resistance of the first floor cold-formed steel composite walls in six stories residential structures, plastic shell element is used, materials nonlinearity and geometric large deformation are considered. The screws connecting sheathing and frame are modeled through coupling methods. Analyzing the influence of factors such as stud spacing，Brace and rigid bracing's establishment，component wall thickness to the shear behavior of cold-formed steel composite wall， these dates can provide certain theory for the actual project.
Abstract: Ultrafine α-Fe2O3 nanoparticles have been synthesized by a facile hydrothermal method. The products were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM). The diameter of the as-obtained α-Fe2O3 nanoparticles is about 6.8 nm on average. The solvent have great effect on the morphology of the final products. Furthermore, the effect of ultrafine α-Fe2O3 nanoparticles on the thermal decomposition of ammonium perchlorate (AP) was investigated by thermal gravimetric analyzer (TG) and differential thermal analysis (DTA). The thermal decomposition temperature of AP in the presence of α-Fe2O3 nanoparticles was reduced by 99 °C.
Abstract: A new 2D metal-organic coordination polymer [Ce(3,4-pydc)2]·H2O(1) was synthesized by hydrothermal reaction of Ce(NO3)3·6H2O and 3,4-pydc (3,4-pydc = 3,4-pyridinedicarboxylate). The structure was characterized by elemental analysis and IR spectroscopy. Single crystal was determined by X-ray single crystal diffractometer. The crystal belongs to monoclinic crystal system and P2(1)/c space group. Crystallographic data: a = 14.501(3) nm, b = 6.7980(19) nm, c = 14.590(3) nm, α = 90°, β = 94.497(2)°, γ = 90°, V = 1433.8(5) nm3, Z = 4. X-ray analysis reveals that the complex is a two-dimensional thick belt structure, and the hydrogen-bonding and p-p stacking interactions between belt layers extend the complex into a 3D supramolecular architecture.
Abstract: For the measurement of shearer shaft geometry signal contain the axis of rotation error and the measurement error, made of two separate programs from shearer shaft the geometric method of measuring signal acquisition and signal processing error. The program is based on the analysis of the shearer shaft Two-point method of roundness measurement method and error separation technique. Using two displacement sensors and a combination of programs to measure the angle sensor, and an equation using the Fourier transform of elimination and separated from the measurement signal roundness. Then, 53H, and wavelet signal Noise algorithm such as the error of roundness error signal separation. Simulation results show that the method has a higher real value and better convergence for coal mining shaft roundness error in the separation of signal processing.