摘要: Mesoporous zirconias were prepared by precipitation method using rosin-based quaternary ammonium salt as a directing agent. The samples were characterized by means of XRD, FT-IR and N2-adsorption and desorption measurements. The phase of precursors was amorphous, and well crystallized tetragonal zirconias were obtained after the calcination at 450 °C. The synthesized mesoporous zirconias possessed high surface areas ranging from 183.56 to 203.87 m2g-1 and big pore diameters varying from 6.27 to 7.58 nm. The content of the rosin-based quaternary ammonium salt had significant influence on the textural properties of the mesoporous zirconias. Surface areas, pore volumes and pore diameters of the mesoporous zirconias decreased when increasing the surfactant dosage.
摘要: The mechanical properties and microstructures were investigated for AZ80 Mg alloy during plane strain compression and extrusion processing. The results show the tensile strength increases with the increasing deformation degree in the two-phase zone due to sufficient dynamic recrystallization and work-hardening effect. In single-phase zone, the tensile strength increases firstly and then does not varies basically when the deformation degree is greater than a certain critical value. This is very beneficial to optimize processing parameters to obtain microstructure with improved mechanical behavior.
摘要: As a new kind of pavement material, the Open Graded Friction Course (called OGFC) has many advantages, and so is rapidly popularized in China recently. However, the performance of OGFC decreases with the utilization of road, such as the decrease in permeability, durability and so on. In the present study, the influence of the shape of coarse aggregate, which is the most important material in OGFC, on the performance of OGFC was investigated in laboratory. The shape of coarse aggregate is indicated by the bulk density and total 4 kinds of aggregates with different bulk density were produced artificially and tested in this study. When the shape of coarse aggregate changed, the wear resistance and dynamic stability of OGFC also changed lightly. The bulk density of aggregate has no serious influence on the void content, but has obvious influence on the permeability of OGFC. The shape of continuous void in horizontal cross-section becomes rounder when the aggregate with large bulk density is used. The rounder continuous void is benefit for the flowing of water, so the permeability of OGFC is improved.
摘要: With phthalic anhydride, urea, metallic salt and ammonium molybdate as raw materials, Cobalt metal phthalocyanines is prepared by solid-phase method, and the cobalt metal phthalocyanine is modified by the shun dl-aspartic acid anhydride. In the homogeneous conditions, the effects of the reaction temperature, the reaction time, phthalocyanine dosage and initiator dosage are studied. The experimental results show that the grafting polymerization products with the highest grafted rate can be prepared under the optimal experimental conditions, which are found to be 60°C for the temperature, 3h for the reaction time, 0.08g for the potassium persulfate and sodium thiosulfate. The product is analyzed by means of IR, the results show that the chitosan is grafted successfully, and the reaction may occurs on the amino and the hydroxyl of chitosan.
摘要: By adding potential crosslinking agent--hydroethyl methacrylate (HEMA), the oil-absorptive fiber with semi-IPN structure CPMAF were prepared using heat crosslinking technology after spinning. The crosslinking structure of the fiber was researched. The results showed that the oil absorbency of fiber with semi-IPN structure was higher than the chemical crosslinked copolymethacrylate particle.
摘要: 75Au25Cu was the basic rosy gold alloy for jewelry, but it had no good brightness and was prone to tarnish and darken. This paper modified this basic alloy through multiple elements and less (micro) alloying, and measured its color and discoloration-resistance. The results showed that small amounts of zinc plus trace of silicon and cerium helped to improve the color and discoloration-resistance of the alloy, the initial colorimetric values fell in between 5N-18 standard alloy and 75Au25Cu basic alloy, while the brightness reached nearly 86, implying that the color was superior to the requirements of EN28654:1993 and ISO8654:1997. Moreover, the test alloy had better preferable resistance to darkening, discoloration and oxidation. All these performances indicated that the test alloy could meet the color requirement of rosy gold for ornaments such as clocks & watches and jewelries.
摘要: A novel photochromic diarylethene based on isoxazole moiety was synthesized and its photochromic and fluorescent properties were also investigated. It underwent reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light in hexane and in PMMA film. The compound exhibited remarkable photochromism, changing from colorless to purple after irradiation with UV light. When irradiation with UV light, the fluorescence intensity declined remarkably. The results showed that the diarylethene exhibited a relatively strong fluorescence switch along with the photochromism from open-ring isomer to closed-ring isomer. Using this dithienylethene 1c as optical storage was performed successfully.
摘要: This study focuses on the manufacturing process of veneer composite plank and test the mechanical properties.The results showed that: ① In the dipping process, when the dipping time was 20min and adhesive solids was 25%,the veneer composite plank can get a better mechanical properties; ②In the low-temperature drying process, according to the mechanical properties and drying efficiency, low drying temperature appropriate select 50°C; ③Considering the mechanical properties and the cost issue as the density increases, select the density of 1.0g/cm3 is appropriate. Prove that the production technology is feasible, its products have uniform texture and good mechanical properties can be widely used for furniture, flooring and structural materials and other fields.
摘要: In the presence of Cu2+ ions, the photocatalytic hydrogen evolution from a methanol aqueous solution was achieved when potassium hexaniobate nanotubes were used as the catalyst. It was found that there existed a photo-induced period in the initial reaction stage. Furthermore, the photo-induced period was prolonged by increasing the amount of Cu2+ ions. After that, the rate of hydrogen evolution was dramatically improved. Combined with the reaction phenomena and the result of the photocatalytic hydrogen evolution, it was deduced that the Cu2+ ions captured the photo-generated electrons of potassium hexaniobate nanotubes in the photo-induced period. Consequently, the Cu2+ ions were reduced and deposited on the potassium hexaniobate nanotubes. When the mass ratio of Cu to potassium hexaniobate nanotubes was 3 wt%, the rate of hydrogen evolution over the catalyst reached 21.9 mmol·g-1·h-1, which could almost match with Pt as a co-catalyst. These results showed that Cu was an effective alternative to Pt as a co-catalyst of potassium hexaniobate nanotubes for the photocatalytic hydrogen evolution from the methanol aqueous solution.
摘要: The pompon-like microspheres of AgIn5S8 with a cubic phase were prepared in a low temperature aqueous solution using mercaptoacetic acid as capping agent and thioacetamide as sulfur source and characterized with XRD, UV-vis absorption spectra, SEM and BET analysis. It is interesting that the microspheres are quite open and puffy. More importantly, the obtained microspheres showed remarkable photocatalytic activity for the degradation of methyl orange under visible light irradiation, which is probably due to the pompon-like morphology for providing reactive sites and facilitating the charge transfer between the target pollutant and the photocatalyst. This method could be extended to the synthesis of other functional micro/nano materials.