Abstract: We found that welding rod of the same trademark but different batch has distinct different tendency of brittleness when they are experienced step cooling embrittling treatment process.A series of 2.25Cr-1Mo-0.25V steel welds were prepared using the manual arc. The notch toughness properties were assessed in the PWHT condition and after a temper embrittlement step-cooling treatment. the J and X factors of the weld should be more rigorous than the base steel. low Mn and Si content weld metal is less susceptible to temper embrittlement. The temper embrittlement was evaluated as the shift of 54 Joule transition temperature (vTr54) by the Charpy v-notch impact tests. In the post-weld heat-treated condition (PWHT) the notch toughness requirement for weld metal is 54 J at-40°C .
Abstract: Bias voltage assisted hot filament chemical vapor deposition (HFCVD) was adopted to deposit boron-doped diamond (BDD) film on porous titanium substrate, and diamond composite membrane materials were prepared and characterized by X-ray diffraction method. The influence of carbon concentration, boron source concentration, substrate temperature were discussed respectively on the diamond quality and the transition layer TiC. Results showed that: The concentration of carbon source was related to crystal orientation and the growth rate of diamond. The increase of diamond nucleation density and growth rate prevented the formation of TiC, and improved adhesion between diamond and the substrate; The increasing of boron source concentration promoted the orientation growth of diamond film (111) lattice plane, while reduced the content of TiC; Temperature affected the formation of TiC, and TiC diffraction peaks intensity decreased with the increase of substrate temperature; As the substrate temperature increased, secondary nucleation rate caused cauliflower-like structure which dominated growth mechanism transitting from MCD (Microcrystalline diamond) to the NCD (Nanocrystalline diamond).
Abstract: According to continuous cooling transformation curve of pinion steel, heat treatment simulation tests of 8 series were developed. The results show that the microstructure of pinion steel depends on the cooling rate after normalizing. Furnace cooling according to 30°C/h after normalizing can get the typical F+P organizations; Converter cooling after normalizing mixed with some bainite organizations; Furnace cooling with the break after normalizing can get clear stripped bainite organizations.
Abstract: Considering the actual factors such as axial compression ratio, constraint conditions and so on, We design 10 beam-column joints of different parameters under the condition of the same reinforcement ratio and use the monotonic loading type to study the influences of dosage of recycled aggregates and waste fibers, waste fiber length on beam-ends load-displacement relationships of beam-column nodes. Experimental research shows that when the dosage of recycled aggregates is 50% , waste fiber content is 0.12%, waste fiber length is 19 mm, beam-end bearing behaviour of node area is best.
Abstract: The different fracture characteristics of self-compacting rock-filled concrete with large-size natural and recycled aggregate are analyzed by three-point bending experiment. According to the analysis of the crack propagation process, the fracture mechanism differences of self-compacting rock-filled concrete with large-size natural and recycled aggregate are discussed. The further analysis of the differences of fracture toughness, fracture energy, and are gain
Abstract: Liquidus temperature, electrical conductivity and phase composition of Al2O3-CaO-SiO2-CaF2-MgO slag system were studied. The results showed that the liquidus temperature of the slag decreased with increasing MgO content, and its electrical conductivity increased with increasing MgO content and temperature. When the content of MgO is 5 %, the main phase compositions of the slag are composed of MgAl2O4, Ca2SiO2F2, CaAl4O7 and Ca5Al6O14. When the content of MgO is 7 %, the main phase compositions of Al2O3-CaO-SiO2-CaF2-MgO are composed of MgAl2O4, Ca4Si2O7F2, CaAl4O7 and Ca5Al6O14.And the content of MgAl2O4 and Mg2SiO4 increased with increasing MgO.
Abstract: A helicon wave plasma (HWP) discharge with strong magnetic field was investigated. The HWP was produced with an internal Nagoya III antenna that is perpendicular to the magnetic field and driven by a 13.56 MHz radio-frequency (RF) source. HWP was characterized in terms of electron density, electron temperature and plasma potential using a single Langmuir probe in Ar gas. The result of Langmuir probe shows that the electron density increases with RF power, but saturate above 700 W at a density of 2×1019 m-3. Scanning electron microscopy (SEM) was extensively used to characterize the quality of the graphite surface. The result of SEM shows the surface of graphite that exposed to plasma processing has exhibited smoother and compacter surface topography. Meanwhile, the concentration of impurity on the graphite surface decreases with plasma processing.
Abstract: In this paper, W-doped TiO2 (W-TiO2) powder was prepared in hydrothermal method by mixing TiO2 and ammonium metatungstate. The catalysts were characterized by X-ray diffraction and ultraviolet spectrophotometer. The results displayed that W-TiO2 showed an anatase crystallite structure with 2 % W content. W-element in W-TiO2 was amorphous state. The guaiacol was degraded with the W-TiO2 in the visible light. It was a model compounds of lignin existed in the plant fibers. The degradation rate of guaiacol was increased with the photocatalytic time, as high as 88.21 % after 360 min irradiation. It was concluded that the W-TiO2 had an obvious photocatalytic activity under visible light. It can be used in the photocatalytic degradation of lignin.
Abstract: PE/thermochromic composite membrane is a kind of new functional materials which is composited by PE and thermochromic membrane.PE/thermochromic composite films retain the thermochromic membrane performance of changing the color by absorbing the heat. The composite film cannot be dissolved by water because of the structure which PE film is attached to the both sides of thermochromic film.The effect of the composite film and Nylon/low density polyethylene (LDPE) film on quality of fresh pork meat stored were investigated respectively. The treated meat samples were analyzed periodically for color difference. The results indicate that preservation effect of both films has no significant difference when the fresh pork are stored at 3-5°C, but PE/thermochromic composite films has better preservation effect at 30°C in compared to the Nylon/ LDPE. filmsfilms