Advanced Materials Research Vols. 538-541

Abstract: Supported phosphotungstic acid SBA-15 were synthesized under hydrothermal conditions and characterized by X-ray diffraction (XRD), N2 adsorption, transmission electron micrographs (TEM), scanning electron micrographs (SEM), Fourier-transform infrared spectroscopy (FT-IR). XRD and FT-IR results indicated that the substitution of tungsten occurs in the silicate framework structure of SBA-15. TEM and SEM investigations confirmed the presence of ordered high degree ordering hexagonal structure in the novel PW/SBA-15 material. Their catalytic activity was evaluated in the epoxidation of α-pinene. 2,3-epoxypinane was the main product. The results of epoxidation of α-pinene by PW(40)/SBA-15 were fellows: the conversion rate of α-pinene and the selectivity were 87.61% and 79.90% respectively.

Abstract: Nitrogen is one of harmful elements in liquid steel. Reducing nitrogen quantity is required for making high-grade steel. This paper analyzes the reaction mechanism of nitrogen increasing through the methods of metallurgical thermodynamics and dynamics. In liquid steel dissolved nitrogen and nitrides are the main forms of nitrogen. The factors of influence on nitrogen increasing are temperature, kinds and quantity of the alloying elements in the liquid steel, , the lifetime of foam in foam slag, the quantity of flow of argon and so on. Analytical results of metallurgical thermodynamics and dynamics are verified by measuring nitrogen content in the links of LF refining process of new developed area of Chongqing steel and iron Co.Ltd.

Abstract: Synthetic Hydroxyapatite (HA, Ca10(PO4)6(OH)2) have the ability to provide the appropriate, scaffold or template for bone formation because of similar chemical and crystallographic structures to bone. The addition of 10wt. % of Ti powder in nano-HA powder was done by using ball milling. The different sintering temperatures at 1000, 1050, 1100, 1150 and 1200°C of nano-HA-Ti pallet were studied. Nano-HA-Ti pallet after vary sintering temperature were tested by hardness and compression strength tests. The optimum sintering temperature to sintered nano-Ha-Ti was at 1200°C because it gave the highest hardness and compression values which were 290.80HV and 78.49MPa. From Scanning Electron Microscopy (SEM) analyzed, nano-HA-Ti particles at 1200°C showed the attachment of nano-HA powder with Ti powder at grain boundary and some crack had form.

Abstract: In this letter, γ-Zn₃(PO₄)₂: Mn²⁺ phosphors have only one emission band centered at 620 nm while two emission bands are observed in γ-Zn₃(PO₄)₂: Mn²⁺, Ga³⁺, which are respectively centered at 507 nm and 620 nm. The spectral overlap between the green emission band and the excitation band monitored at 620 nm, which supports the occurrence of the energy transfer from Mn²⁺ (CN=4) to Mn²⁺ (CN=6), has been studied. The influence of Ga3+ ions on luminescence and long lasting phosphorescence properties of Mn²⁺ in phosphor γ-Zn₃(PO₄)₂: Mn²⁺, Ga³⁺ are also investigated. It is found that the green/red phosphorescence performance of Mn²⁺ ion such as brightness and duration is largely improved when Ga³⁺ ion is co-doped into the matrix in which Mn²⁺ ion acts as luminescent center and Ga³⁺ ion plays an important role of electron trap.

Abstract: Facing great pressure of economic growth and energy crisis, China has paid more attention to the renewable energy and cellulosic ethanol has received increasing attention in recent years. The key from lignocelluloses to bioethanol is how to produce fermentable sugars effectively by hydrolysis of cellulose. Chemical, biological pretreatment and hot water pretreatment are considered as three important techniques for high yields of fermentable sugars from lignocellulosics. In this review, the three important techniques for high yields of fermentable sugars from lignocellulosics and the pretreatment study status, challenges, and future research targets were discussed.

Abstract: The mixed valence copper Cu2SO3•CuSO3•2H2O with durian-like was synthesized by a simple hydrothermal method at 80 °C. The double sulfites obtained were identified by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical performance of the salt was evaluated by cyclic voltammetry (CV) and charge-discharge test as the lithium ion battery electrode material. The electrode exhibited high initial discharge capacity but extremely low charge capacity, which illustrates that Cu2SO3•CuSO3•2H2O is not suitable for lithium ion battery electrode negative material.

Abstract: The morphological structure and properties of wet natural rubber (NR) granulates dried by microwave were studied, which compared with wet NR granulates dried by hot-air. The results show that the molecular weight of NR dried by microwave is higher than that of NR dried by hot-air, and the molecular weight distribution of NR dried by microwave is narrower than that of NR dried by hot-air. The wet NR granules dried by microwave are rough on surfaces and the cutting traces produced during the processing remained on surfaces; whereas the wet NR granules dried by hot-air are smooth on surfaces resulted from melt adhered, and the cutting traces disappeared; the thermal-oxidative resistance of NR vulcanizates dried by microwave improved significantly.

Abstract: Applying microwave heating and impinging hot-air is one of the most interesting methods to increase the higher drying rates of rubberwood drying based on acceptable quality. A maximum microwave power level of 200W at a frequency of 2.45GHz with maximum working temperature of 70°C, only hotair (70°C) and combined microwave (200W) - hotair (70°C) were choosed to evaluate the effect of rubberwood drying by different width sizes (1, 2, 3 and 4 in.) by 46 in. length by 1 in. thick. In all cases, the drying time is reduced significantly from 168 h to less than 8-15 h in various wood widths and resulted in saving to an extent of about 91% of drying time from initial moisture content ranges of 73%-49% to 15% percent of moisture level. Drying stresses from prong test no found during drying and total color of rubberwood changed after high temperature drying is a natural surface when compared to fresh wood. The values of six strength compared to the reference values are concentrated in the ranges of 16.9-23.9 (11.0)MPa for shearing strength parallel to grain, 4291.1-6701.6 (4350)N for hardness, 73.3-110.2 (66.0)MPa for MOR, 7059.5-12856.7 (9240.0) MPa for MOE, 27.2-14.3 (5.0)MPa for compressive strength perpendicular to grain and 60.6-35.7 (32.0)MPa for compression strength parallel to grain. These results show that it is possible to develop a drying process for rubberwood using microwave-hot air in investigating further in this area.

Abstract: The Methanol to olefins (MTO) and ethanol to olefins (ETO) reactions were compared under the similar operation conditions, and it was proved that both follow the different reaction mechanism over H-ZSM-5 catalysts. In MTO reaction, dimethyl ether (DME) acts as the initial intermediate, which then follows two different reaction pathways depending on the acidity of H-ZSM-5 catalysts, namely, the dehydration of DME into ethene over higher acidity of H-ZSM-5 catalysts and the merization of DME through hydrogen bonds into (DME)n (n = 2-4) complexes over lower acidity of H-ZSM-5 catalysts. Further, over higher acidity of H-ZSM-5 catalysts, ethene converts into propene and butene, and thereafter undergoes the oligomerization-craking-aromatization route to form other olefins, paraffins and aromatics. But over lower acidity of H-ZSM-5 catalysts, (DME)n complexes tend to transform into high even number of olefins that are easily cracked into small olefins. In the case of ETO reaction, ethene acts as the main reaction intermediate, which then transforms into propene and butene, and further proceeds through the oligomerization-craking-aromatization route to form other olefins, paraffins and aromatics products over H-ZSM-5 catalysts.

Abstract: By analysis of measure theory, test method, goal seeking process, discuss test method in theory, A diffusion equation based on seepage theory is brought forward to substitute the linear fitting method. Data process complexity is being decreased.