Advanced Materials Research Vols. 971-973

Abstract: Though the study of carbon content on the microstructure and properties of gray cast iron, mechanical properties test as well as metallographic observation, we could see that the mobility of molten iron is the best when carbon equivalent control at around 4.3%; Liquid iron tend to precipitate A or B type graphite and enhance the casting organization and property when carbon content was increased properly.

Abstract: The quality of kiwifruit with three different packaging films were studied on the storage days. These kiwifruits were stored at 0±0.5°Cfor 120 days. Results showed that the kiwifruits with PVC films can keep a relative good quality during the storage life.

Abstract: An experiment was carried out to evaluate the effects of initial phosphorus concentration (0, 0.54, 2.7, 5.4, 10.8and 16.2mg/L) on chlorophyll a (chl-a) contents and extracellular polysaccharides (EPS) contents of Scenedesmus quaclricauda, which was separated and purified from the Three Gorges reservoir (TGR). The different conditions of initial phosphorus concentration have different volumetric meanings. 0mg/L, 0.54mg/L and 2.7mg/L are P-limited, 5.4mg/L is P-standard, 10.8mg/L as well as 16.2mg/L, is P-rich. Results showed that the growth period of Scenedesmus quaclricauda was shortened, and the stationary phase happened earlier than usual in the condition of P-limited. However, the growth period of Scenedesmus quaclricauda got a proceeding extension in the condition of P-rich. The condition of P-rich had an inhibitory effect on the growth of Scenedesmus quaclricauda during lag phase and exponential phase. It seemed that there was an inhibition threshold of initial phosphorus concentration, which was between 5.4mg/L and 10.8mg/L. And the inhibitory effect decreased with the initial increasing phosphorus concentrations from 10.8mg/L to 16.2mg/L. One-way analysis of variance (ANOVA) was used to compare the effects of both P-limited and P-rich and their impact on sEPS contents and bEPS contents of Scenedesmus quaclricauda in the cultured time segments. The results showed that there was no significant difference at sEPS contents or bEPS contents either in P-limited or P-rich. In the whole culture period, the sEPS contents of Scenedesmus quaclricauda had small fluctuations but kept nearly unchanged. Whereas, the bEPS contents increased in the beginning 8 days, and then dropped to the level, which is slightly higher than the initial contents, and keep fluctuating steadily. The EPS contents were just floating up and down at the initial value and had not shown a trend of rising or falling precisely. Our results suggest that phosphorus concentration could change chl-a contents but have no significant effect on EPS contents.

Abstract: Taking red grape as material, studied on the effect of SO₂ interval fumigation treatments on color and antioxidant of red grape, which is stored under 0 °C. The concentration of sulfur dioxide as 0%(CK), 3%(TR1), 5%(TR2) and 8%(TR3) respectively and keep one-hour. The results indicated that TR2 showed a remarkable ability to inhibit decreasing of Vitamin C content, and 52.3% higher than CK, and SO₂ residue is under the FDA standard. This study showed that 5% SO₂ fumigated for one hour is the best treatment, and keep the grape storage quality significantly.

Abstract: In this paper, the commercial α-SiC powder and bargain price La₂O₃/Y₂O₃ additives were utilized to fabricate SiC matrix composites. The influence of the Y₂O₃/La₂O₃ molar proportion on the microstructure, mechanical properties of the C_f/SiC composites were researched. The results showed that La₂O₃/Y₂O₃ additives could not enhance mechanical properties for the C_f/SiC composites distinctly. The flexural strength for the C_f/SiC composites with different Y₂O₃/La₂O₃ proportion was higher than 250MPa. The multi-toughening mechanics including grain bridge, crack deflection and fiber pullout were responsible for improvement of fracture toughness.

Abstract: The ZrO₂-Mg-HA powders were fabricated by the chemical precipitation and pressureless sintering technology. The dental filling materials were prepared in combination with ZrO₂-Mg-HA powders and polymethacrylate. The phase composition, fracture morphology and mechanical performance of the ZrO₂-Mg/HA composites were investigated in details. The results showed that the introduction of moderate content of the ZrO₂ was benefit to improve the compressive strength of the material. The investigated ZrO₂-Mg/HA composites could meet the requirements for the dental filling materials.

Abstract: This paper educes the mathematics formula of solid-liquid phase dielectric constant by employing two methods of mixture’s dielectric constant, building on the electromagnetic wave through the medium theory, this paper thus obtains the mathematic theory model of online microwave water content detection in iron concentrate. Finally, this paper identifies and revises the mathematic model through experiments.

Abstract: To study the geometrical and electronic structure of 15R-SiC polytypes, the lattice parameter, band structure, density of states (DOS) and charge density of 15R-SiC are calculated by using density functional theory based on the plane wave pseudopotential approach, and electronic structure and ground properties of 15R-SiC are investigated by the calculated band structure and DOS, the results show that 15R-SiC is an indirect band gap semiconductor, with calculated indirect band gap width being 2.16 eV and band gap dependent on Si 3p and C 2p states. While charge density results show that Si-C bond is a hybrid bond semiconductor strong in covalent bond and weak in ionicity, characterized by intense sp³ hybrid characteristics, which is in accordance with the experimental results. The above mentioned results are considered as theoretical reference for design and application of SiC polytype materials.

Abstract: A novel antimicrobial poly (lactide) (PLA) film incorporated with clove essential oil (0, 2%, 4%, and 6% (w/v)) was developed. The mechanical property, water vapor permeability, color, contact angle, and antimicrobial activity of the films were investigated. The flexibility of films was improved by incorporation with clove. The water vapor permeability slightly increased with clove content. PLA film containing clove showed better antimicrobial activity compared to pure PLA film. The results suggested that PLA/clove blends could be a novel composite film for food packaging applications.

Abstract: The micro-arc oxidation technology were utilized to fabricated the ceramics coating in order to improve the corrosion resistance of Ti–6Al–4V alloy (TC₄). The sodium silicate solution was introduced into the electrolyte solution for increasing the coating properties. The effect of the sodium silicate content on the phase composition, surface morphology and potentiodynamic polarization behavior was investigated. The results showed that the increase of Na₂SiO₃ concertration was benefit to improve corrosion resistance of the MAO coating of TC₄ alloy. Key words: Micro-arc oxidation, Ceramic Coatings, Corrosion Resistance.