Advanced Materials Research Vol. 787

Abstract: Silica sphere has wide applications not only in the field of physical chemistry dealing with dynamic behavior and stability of particulate systems, but also in industries including catalysts, ceramics, pigments, pharmacy, etc. However, the control on the particle size is a key factor in the preparation process of silica sphere. In this paper, silica sphere with uniform sphere morphology and amorphous structure was prepared by a sol-gel method, and the control of particle size was emphatically studied. The results showed that the particle size of the as-prepared silica sphere was obviously influenced by the raw materials concentration. The average size of the product increased from 0.66 μm to 0.90 μm when ethanol concentration increased from 7.14M to 9.55M, increased from 0.50 μm to 0.90 μm with the increase of ammonia concentration in the range of 1.88M to 2.36M, and increased from 0.47 to 0.90 μm while tetraethoxysilane concentration increased from 0.08M to 0.11M. Further study indicated that the silica particle size was also influenced by reaction temperature, it increased with the increase of temperature from 26°C to 28°C, and decreased with the further increase of temperature in the scope of 28°C to 32°C.

Abstract: The LiFePO₄/C composites with different morphology are synthesized by a novel glucose assisted hydrothermal method at various glucose concentrations (from 0 to 0.25mol/L) and the insoluble lithium source Li₂CO₃, (NH₄)₂Fe (SO₄)₂·6H₂O and (NH₄)₂HPO₄ (n (Li):n (Fe):n (P)=1:1:1) are used as raw materials. The structure, morphology, thermal performance and electrochemical properties of the synthesized composites are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetry/differential scanning calorimetry (TG-DSC), galvanostatic charge/discharge tests and cyclic voltammetry (CV). The results show that the LiFePO₄/C synthesized with 0.125mol/L glucose has the relatively small particles size (0.1~0.5μm) and the well spherical morphology. The optimal sample exhibits a high discharge capacity of 160.0mAh/g at the first cycle and exhibits a good reversibility and stability in CV tests.

Abstract: Ultrathin silica films were grown on polyimide substrates using surface sol-gel method and the film growth process was characterized by ellipsometry, atomic force microscopy, X-ray photoelectron spectroscopy, Fourier transformed infrared spectroscopy. The polyimide substrates were pretreated by chemical process for promoting the growth of silica film. On the modified polymide surface, the growth of silica films shows an island-like growth type, but not a lay-by-lay process. Moreover, the deposited silica films are not a strict SiO₂ film.

Abstract: Based on the common used coals and designed coal in a power plant in Hunan, a non-linear coal blending model was built. Exhaust algorithm, genetic algorithm and simulated annealing algorithm were used to solve the model respectively using the lowest cost of the blended coal as the objective function. Three kinds of single coals were blended together according to certain proportions based on 15 kinds of common used single coals. The coal characteristics of blended coals were predicted by the model of General Regression Neural Network. The cost, fitness and predicting time obtained by three different algorithms were compared and analyzed. The results show that the solution is ideal in cost and fitness with exhaust algorithm while the predicting time is very long. GA algorithm is good in cost, computing time and reliability.

Abstract: In the current study, Laboratory uniaxial compression tests are carried out in order to determine the strength and mechanical behavior of silty sand reinforced with randomly distributed short resinous Polypropylene (PP) fibers. The stress-strain behavior of composite materials is investigated through varying the number and length of PP fibers. In order to study the effects of the length and weight percent of fibers on the results of the uniaxial compressive strength, tests were accomplished on specimens with three different lengths and weight percentages of fibers. The results demonstrate increasing weight percent of fibers, in a constant length, leads to increase the maximum strength. Meanwhile, increasing the length of fibers, in a constant weight percent, reduces the maximum strength. Moisture absorbency of fibers which was about 120% at first, however, could be reduced to just 9% by using the epoxy polyamide resin. Moreover, the resin causes more interaction between sand aggregates and fibers leading to a higher internal friction angle.

Abstract: Consumable electrodes of H13 die steel with different magnesium contents were produced by medium frequency induction furnace. Effects of magnesium on deoxidation rate and inclusions in consumable electrode were studied. Results show that the deoxidization ability of Fe-Al-Mg alloy is better than that of aluminum and the dissolved oxygen content is decreased with the increase of magnesium content in liquid steel. The deoxidation rate is less than 15 % for steel without magnesium and more than 24 % for steel with 20 × 10^-4 wt% magnesium content. The number of inclusions is decreased with the increase of the magnesium content in steel. Because tiny MgO·Al₂O₃ inclusions are generated in the steel containing magnesium, the number of inclusions with size less than 2 μm is increased obviously and the number of inclusions with size larger than 5 μm is decreased. Some VN and VN-TiN inclusions with size less than 10 μm are precipitated taking MgO·Al₂O₃, MgO, MgS as cores in the steel containing magnesium.

Abstract: 80nm-thick network Ni films were sputter-deposited on anodic aluminium oxide (AAO) substrates at 300 K and 573 K. The network films are formed by granule connection. The granule consists of many fine grains. Both granule size and grain size are independent of the deposition temperature. A temperature dependence of the resistance within 1.6-300 K reveals that the network Ni film grown at 300 K exhibits a minimal resistance at about 25 K while that grown at 573 K does not show a minimal resistance. A temperature coefficient of resistance of the network film grown at 573 K is larger than that of the film grown at 300 K.

Abstract: Development and utilization of renewable energy alternative to traditional fossil energy is the most effective solutions to global energy crisis and sustainable development. According to theory of technical economic analysis, the technology and energy efficiency of bioethanol to produce liquid fuel was discussed and analysis by life cycle assessment, including production, greenhouse gas emission, as well as economic and social impacts. On this basis, according to the conditions and requirements of Chinese economic and social development, the policies and measures that should be taken by research, application and research priorities of bioethanol technology in China is proposed.

Abstract: Molecularly imprinted techniques have been rapidly developed in recent decade. Some novel molecularly imprinted techniques and some novel application forms of molecularly imprinted polymers have been developed. And it has been widely used in sample pretreatment. In this paper, novel mixed-template molecularly imprinted techniques are introduced. The development and applications of mixed-template molecularly imprinted techniques in recent decade are reviewed, including dual-template molecularly imprinted technique and multi-template molecularly imprinted technique, and its application in chromatographic solid phase, solid phase extraction and microsphere extraction. Moreover, the trends of mixed-template molecularly imprinted techniques in sample pretreatment are prospected.

Abstract: In order to reveal impact of environment humidity and temperature on properties of indoor decorated materials, the paper tested physical and mechanical prosperities of 5 kinds of wood-based panels according to European standards after equilibrium treatments in 3 types of atmosphere. The results showed that the tested materials were very hydrophilic and their strength were closely related to moisture content. Internal bond, modulus of rupture, 24h-thickness swelling and surface soundness of wood-based panels decreased at high temperature and high humidity atmosphere and increased in low temperature and low humidity surroundings, and the decrement are greater than the increment. In contrast, density almost kept the same value during these treatments.