Abstract: This study is aimed to evaluate the impact performance of cement-based composites which comprise steel fibers and silica fume in the mixes. Material variables include water-cementitious ratio, dosage of silica fume, steel fiber length and dosage. Test results indicate that the impact resistance increase with increasing fiber content and water-cementitious ratio, and with decreasing silica fume content. For a given volume fraction, short fiber performs better than its long counterpart in improving the impact performance. In addition, the combination of silica fume and fibers enhances better impact behavior than individual constituents of silica fume, due to reduced the crack formation and offer the toughness of cement-based composites under impact loadings.
Abstract: The effect of magnetic field on the morphology and properties of Cu2O has been investigated by using a high magnetic field (B = 7 T) during the synthesis of Cu2O. Transmission electron microscopy (TEM) images showed that the variation of Cu2O crystal microstructures from nanospheres to nanoparticle-aggregates under the introduction of external magnetic field. And the optical band gap energy (Eg) of Cu2O was changed from 2.51 eV (nanospheres) to 2.27 eV (nanoparticle-aggregates). The effect of high magnetic field on the structure and properties is expected to be widely used to improve various crystals.
Abstract: Fe2O3 content affects the physical property of geopolymer paste made from waste materials. The effect of Fe2O3 was evaluated in this research. Geopolymer paste was made from the mixtures of mine tailing, melting slag, and alkali activator. Fe2O3 was added to discuss its effect with increasing the content. Compressive strength was 73.6 MPa without adding Fe2O3. But it was lowered to 32.5 MPa at the addition of 5wt. According to the analyzing results of XRD, SEM and EDS, Fe2O3 inhibited the geopolymer formation. Therefore, it is necessary to control the content of Fe2O3 to enhance the physical characteristics of geopolymer paste through the process of preparation.
Abstract: In order to study influence of buffer layer on intense pulsed field emission (IPFE) of carbon nanotube films (CNTs), CNTs were synthesized on Si substrate with different buffer by pyrolysis of iron phthalocyanine (FePc). The buffer layer including Ni and Au/Ni were prepared by using electroless plating process. The surface morphologies of the films were characterized by field emission scanning electron microscopy (SEM). IPFE properties of CNTs were measured with a diode structure in single-pulse mode. It was found that the emission ability of CNTs were improved obviously by introducing buffer layer,and Au were better than Ni as buffer layer. At the same peak electric field intensity ~11.4 V/µm, The even turn-on field decreased from 6.7V/µm for Si- CNTs to 5.9 V/µm for Ni- CNTs to 4.6V/µm for Au- CNTs (the CNTs synthesized on Si substrate with Au/Ni buffer,Ni buffer and without buffer was abbreviated as Au-CNTs , Ni- CNTs,Si-CNTs, respectively) , and the peak emission current increased from 90A for Si- CNTs to 180A for Ni- CNTs to 260A for Au- CNTs.
Abstract: Earthquakes, wind buffeting, ocean waves， noise vibration and explosion are all harmful to people’s life. For controlling the vibrations one way is by improving the material damping capacity. Effects of improving the damping properties of cement based material by adding polymer, fiber and interfacial modification have been admitted. Whereas the relationship of the influence of the dosage of polymer to the damping functions and the changes of damping behaviors at different frequency, temperature environment have received much less attention. The main objective of this paper is to research the damping behavior of SBR modified cement pastes at different frequencies, temperatures and polymer contents by dynamic mechanical analysis Experimental results showed that the damping behaviors of low P/C ratio cement paste is close to a typical elastic cementitious material and higher P/C ratio resulted in higher damping behaviors. For a certain SBR modified cement paste, Tanδ slightly decreases with the frequency increases and a sharp peak was found at the glass transition temperature. The SEM images indicated that there was a morphological difference in the plain cement paste and SBR modified cement paste.
Abstract: To improve anti-oxidation, anti-wear and extreme-pressure performances of metallic detergents, the over-based substrates of two detergents were modified by partial neutralization with sulfur and phosphor containing carboxylic acids. In this way, two modified detergents were prepared. The non-modified and modified detergents were evaluated by four-ball tester and thermogravimetric analyzer. The results have shown that the modification enhances anti-oxidation and extreme-pressure performance of the detergents without affecting their dispersing ability and anti-wear behavior obviously.
Abstract: The conducting chains in printed CNT film were considered as (MI)iV or (MI)i-1MV configuration. The transport and field emission of electrons in printed CNT film can be considered as tunneling conduction. The transmission coefficient of an insulator barrier surrounding a CNT was calculated via quantum mechanical principle. When an electric field is applied to CNTs, the barrier of residual was considered as a group of rectangular potential barriers. The total transmission coefficient for a residual-covered emitter during emitting was solved numerically from the product of the two transmission coefficient for the potential barriers of residual and the vacuum level.
Abstract: This paper described new effective glass bottle fracture process for glass recycling by underwater shockwave. The high-speed fracture behaviors of glass bottles by explosive energy were discussed. In the proposed technique, the washing process can be skipped because the bottle crushing process execute in water. As a result, the recycling cost can be decreased. In order to clarify the behaviors of glass bottle fracture, the bottle was painted by 5 colors. The crushing experiment was executed under four explosive conditions. The influence of various explosive conditions on the cullet sizes were calcified by using painted bottle.
Abstract: The establishment of a technique for mercury iodide (HgI2) purification and crystal growth is described, aiming this crystal future application as room temperature radiation semiconductor detectors. Repeated Physical Vapor Transport (PVT) technique was studied for purification and growth of the crystal. To evaluate the purification efficiency, measurements of the impurity concentration were made after each growth, analyzing the trace impurities. A significant decrease of the impurity concentration, resulting from the purification number, was observed. A significant improvement in the HgI2 radiation detector performance was achieved for purer crystals, growing the crystal twice by the PVT technique.
Abstract: CS-ACAP drug-loading microsperes are prepared with using CS and ACAP as the main raw materials by emulsification-crosslinking method. Orthogonal experiment was designed to optimize the preparation process of the CS-ACAP drug-loading microspheres. FT-IR and SEM were applied to characterize the structure and morphology of microspheres. The sustained release effect of CS-ACAP microsphere was measured by sustained release measurement. The results showed that the CS-ACAP drug-loading micropheres were successfully prepared by emulsification-crosslinking method. Obtained microspheres as a perforated sphere, the average particle size of the microspheres was 30μm and the microspheres had a uniformly particle size distribution; the drug-loaded microspheres had good sustained release effect.