Advanced Materials Research Vols. 912-914

Abstract: In order to deal with the more and more serious problem of electromagnetic radiation pollution, cement-based composites were prepared by introducing glass fiber into cement as through wave reagent and carbon black as absorbing reagent . Arched testing method were used to test the reflection losses in the frequency range of 2~18 GHz. The results showed that the absorption properties were improved in high frequency compared with the pure cement. The filling ratio of carbon black and glass fiber as well as the thickness of samples had influence on the absorption properties. The lowest reflection loss of-11.2 dB was obtained at 18 GHz of 9wt.% glass fiber and 5wt.% carbon black filled cement with thickness of 10mm. The new material can be used for building indoor electromagnetic radiation protection.

Abstract: The experiment studies how the freeze-thaw cycles influence concrete compressive strength and elasticity modulus with different water-cement ratio under the air-entraining agent and zero of that value respectively. It can be found that modulus of elasticity and compressive strength of the concrete specimen reduced significantly when there is air-entraining agent; the durability of freeze-thaw resistance, however, makes great improvement; as the cement increases, both of them improves effectively. Through the comparison of concrete compressive strength and elastic modulus with different water-cement ratio and air-entraining agent, the optimal water-cement ratio and air-entraining agent were determined. The results of experiment can be used in concrete engineering design in severe cold area.

Abstract: Freezing temperature is one of the main factors of soil frost heave, and different cooling modes will also have an effect on frost heave. To study the influence of stepwise cooling mode to frost heave of silty clay, this paper did the tests of frost heave on the silty clay in stepwise cooling mode and continuous cooling mode respectively, which got versus time of temperature gradient field and frost heave amount in the phenomena of frost heave and frost shrinkage by the two cooling modes. It turns out that stepwise cooling mode will produce greater frost heave and larger frost heave rate, and when frost shrinkage phenomenon occurs, the amount of frost shrinkage is bigger also. Its mechanism lies in the cooling rate with stepwise cooling mode is smaller than that with continuous cooling mode, and it can promote the water migration.

Abstract: This study indicates the micropattern of molded plastic film from a mold insert using ultrasonic micro embossing. A mold insert and plastic film are heated above the glass transition temperature of plastic, and the softened plastic is flowed into the micropattern of a mold insert by applying pressure via a conventional technique. A longitudinal ultrasonic wave is added to the ultrasonic micro embossing process. The longitudinal ultrasonic wave generated by an ultrasonic system at a frequency of 35 KHz, has amplitude of 20 μm and output power of 900 W. The micropatterns of the Ni mold insert are groove-shaped and they are 2-μm wide and 200-nm deep. The Polypropylene (PP) is chosen as the replication materials. This study identifies the replication properties of the plastic film using different process parameters (working pressure, ultrasonic pressure, packing pressure, working time, ultrasonic time and packing time). Results of this study demonstrate that ultrasonic time is the most important process parameter for ultrasonic micro embossing.

Abstract: The crystallization of calcium carbonate was conducted by the reaction of calcium acetate with urea in the presence of polyvinylpyrrolidone (PVP). The morphology and polymorphism of these products were characterized with field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The results showed that hierarchical CaCO₃ spheres were prepared in the presence of PVP. Varying the amount of PVP can prominently regulate the aggregation and self-assembly process of calcium carbonate precursor formed in mixed solvent.

Abstract: The comprehensive properties of the developed warmth retention underwear fabrics and other three selected samples were evaluated by Fuzzy mathematics in the paper. First, on the basis of analysis of the required performance of warmth retention underwear fabrics, the evaluation metrics were determined. Then we used Fuzzy mathematics to establish the comprehensive evaluation model, and with this modle, the comprehensive properties of the four underwear fabric sample were evaluated.The evaluation result showed that wool cover cleancool fiber double-layer underwear fabrics has the best comprehensive property, it is suitable for making high quality warmth retention underwear.

Abstract: In this paper, a technology of graphical simulation was applied to for processing microstructures of Ni-TiN coatings by using cellular automata (CA) model. The results present that the graphical simulation for microstructures of Ni-TiN coatings can be emulated by using cellular automata model in Matlab 7.8 software environment. the average particle size of the Ni grains and TiN particles in the coating prepared by adding 1g/l TiN particles are 188 and 62 nm, respectively. While the average particle size of the Ni grains and TiN particles in the coating prepared by adding 10g/l TiN particles are 67 and 45 nm, respectively.

Abstract: Steel slag has been widely used in the building materials industry. Grinding aid contribute much in this process which can save energy and reduce emission. This paper summarizes the major classes, function and research progress of grinding aids. Various kinds of grinding aids were discussed. Some problems concerning the application and developing trends of grinding aids were put forward.

Abstract: The effective treatment of void cement concrete pavement slab through grouting technology is the important premise of ensuring the service performance of asphalt overlay engineer on cement concrete pavement. Based on the current problems of grouting technology, we did experimental studies on the mixing proportion of grout slurry and analyzed the effects of slurry composition and admixture type on mechanical properties including the strength, mobility, viscosity, expansion rate and bleeding rate of the slurry and on the service performance. Based on these, we put forward the control indexes for grouting slurry mix proportion determination which provided guidance for the design and construction quality control of grouting under the old cement concrete pavement slab.

Abstract: Hierarchical SAPO-11 moelecular sieves were hydrothermally synthesized in the presence of carbon nanoparticles. X-ray diffraction (XRD) and N₂ adsorption-desorption analysis were conducted, which showed that samples prepared with carbon nanoparticles exhibited AEL structure with mesopores centering at 30nm. The product was also characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which showed that the crystal surface became rough and left the mesopore structure with mesopore volume of 0.339 cm³/g after carbon template being burned off. For the hydroisomerization reaction of n-dodecane, the hierarchical SAPO-11 catalyst showed higher isomer and monobranched product selectivity than the traditional SAPO-11, which would be beneficial for n-paraffin upgrading.