Advanced Materials Research Vols. 287-290

Abstract: The skin is the largest organ in the body composed of the epidermis, dermis, and subcutaneous tissue through the latter it is integrated with deeper tissues. The major function of the skin is to shield out attacks, acting as a barrier. The skin can trigger a series of self-healing procedure when it is damaged. The healing process can be divided into three phases: inflammatory, tissue hyperplasia, and tissue reconstruction. Particularly during tissue hyperplasia, fibroblast proliferation and collagen deposition play important roles in the healing. The healing could be accelerated if wound dressing can be properly applied. An ideal wound dressing is capable of absorbing tissue fluid, keeping the wound moistured, stopping bleeding, attaching to the wound surface properly without sticking to the wound tissues, protecting the wound from infection, and accelerating the wound recovery. In this study, the composite membranes was made by adding mixed solutions of low-methoxyl pectin and Bletilla striata, which is a traditional Chinese medicine, into calcium chloride solution. The low-methoxyl pectin is cross-linked with calcium ions, forming a hydrogel. Membranes of varying ratio of the low-methoxyl pectin and Bletilla striata were prepared seeking for the optimal manufacturing parameters to use to investigate its effects on the water stability, water retention, contact angle and degree of swelling of the composite membranes. The results showed that when the ratio of low-methoxyl pectin solutioin (2 wt%) and Bletilla striata extract is 80/20 was added into 40 ml of 0.3 wt% calcium chloride solution, the composite membrane had the optimal performance in terms of the water stability, water retention, and swelling.

Abstract: We have synthesized layered Ni(OH)₂ via a facile liquid-phase precipitation method. NiO with a micro/nano-structure was obtained via calcining Ni(OH)₂ precursor at 350°C. The as-prepared NiO was utilized as a support to load Ag nanocrystals. SEM and TEM observations showed that Ag nanoparticles were homogeneously distributed onto NiO support and the Ag nanoparticles have sizes of 4-5 nm. The photocatalytic activity of NiO-loaded Ag was investigated by the photodegradation of methylene blue (MB) under the irradiation of visible light. The results suggest that the loading of Ag nanoparticles can enhance the photo-degradation performance of pristine NiO.

Abstract: Biodegradable materials have gained more and more attention, especially in biomedical fields. Because of their degradability, biomedical products made of these biodegradable materials can reduce the deleterious impact to the environment. Among other biodegradable polymers, gelatin has been used in wound dressing to accelerate wound healing due to its biocompatibility, film formability and hemostatic activity. In this study, we used gelatin as the matrix for our dressing. As gelatin is prone to degrade/dissolve in water at body temperature, it has to be cross-linked or stabilized with other compounds to enhance its lifetime. Chitosan, another biodegradable polymer, is also widely used in wound healing due to its biocompatibility and antibacterial properties. In this study, we mixed gelatin solution with chitosan solution at a variety of ratios and tested the effectiveness of UV irradiation on cross-linking the two polymers. The composite membranes were fabricated and underwent tests of swelling, stability in water, water contact angle to evaluate their stability and hydrophilicity. Our results showed that the composite membrane made of gelatin/chitosan (90:10) treated with UV irradiation for ten min has the optimal stability in water.

Abstract: Rapid technical advancement threatens the earth ecology, driving people by degrees to develop green energy and green products. Tencel^® fiber uses natural fibers. Products made of Tencel^® fiber could be biodegraded, which solves the problems for the increasing consumptions of disposable nonwoven product. In this research, Tencel^® fiber, polylactic acid (PLA) fiber, and high absorbent fiber (HAF) were used to produce Tencel^®/PLA/HAF composite nonwoven fabrics. Among the nonwoven processing parameters, to increase the Tencel^® fiber content helped heighten the water absorbency. When there were 80 wt% Tencel^® fibers, the basis weight was 100 g/m² and the needle-punching density was 300 needle/cm², the Tencel^®/PLA/HAF composite nonwoven fabric exhibited the optimum water absorbency in cross machine direction (CD), which was 5.0 cm. The air permeability of the Tencel^®/PLA/HAF composite nonwoven fabrics reached 164.4 cm³/cm²/s when the basis weight was 100 g/m² and the needle-punching density was 300 needle/cm²

Abstract: Apparel textiles in service will adsorb metabolism perspiration from human body, thus prompting microbial propagation and leading to fiber degradation and splash. More seriously, this microbe gives rise to allergy and red swelling on human skin, which makes our body unwell. Staphylococcus aureus is one of common bacteria on human skin, but its excessive breeding on skin will bring red swelling and inflammation. In order to avoid this situation happening, we add antibacterial ingredients in textiles which were not harmful to human and cannot have negative effect on human. And this study aims at seeking for anti-staphylococcus aureus plants, trying to add ingredients from plants in textiles to discuss their antimicrobial change and investigating whether to be potential in textiles application. Phyllanthus Urinaria Linn (PUL) is common in tropical East Asia and can suppress the growth of bacteria regarding staphylococcus aureus, typhoid bacillus, pseudomonas aeruginosa etc. It is shown that when PUL was treated at 60°C for 6 hours in 300 ml 95 % ethyl alcohols, extract rate was up to 12.53 %. And qualitative antimicrobial was effective between 12g/100ml and 0.09375g/100ml PUL extract liquor. And the fabric qualitative antimicrobial was obviously valid when extract concentration was above 0.75g/100 ml. Therefore, cotton treated by 1.5g/100ml PUL extract liquor had prominent antimicrobial effect.

Abstract: In this thesis, the new process will proposed which using diamond profile boring to boring 8-shaped hole in intermediate stainless steel plate of synthetic fiber gear pump. Academic analysis was made for gear pump’s flow rate, and analysis was made for the disadvantage of using brown alumina grinding wheel to grinding 8-shaped hole in intermediate plate’s internal surface. The critical technical of single crystal diamond’s material selecting, grinding, welding were solved, and diamond profile boring was designed and manufactured. We confirmed the boring parameters: “”, “” and “” through experiment and academic analysis. The qualified intermediate stainless steel plate with 8-shaped hole was using in one spinning factory; we conquered the grinding hole’s disadvantage and productivity is increasing 15 times.

Abstract: The flower-like α-Fe₂O₃ superstructures were fabricated by a novel hydrothermal route and sequential annealing at 600 °C for 1 h using FeCl₃×6H₂O as the starting precursor. The structures and morphologies of the synthesized flower-like superstructures have been characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM). It is revealed that the flower-like α-Fe₂O₃ nanostructures consist of nanorods with the average diameter of about 70 nm and an average length of about 200nm growing from the centers. The critical role of urea in the hydrothermal synthesis of the flower-like nanostructures is discussed.

Abstract: A magneto-rheological (MR) fan clutch is a device that transmits torque by the shear stress of the MR fluids. In this paper, the torque transmitted by MR fluids is analyzed to compute the torque transmission ability in the disk-type MR fan clutch. The results show that with the increase of the applied magnetic field, the torque developed by MR fluids goes up rapidly. The driven speed of the fan clutch can be adjusted continuously by changing the applied magnetic field.

Abstract: The strength, ultimate tensile value, compressive elastic modulus and drying shrinkage of polyvinyl alcohol fiber reinforced concrete were studied by tests, and its crack resistance property was also studied by plate method and temperature stress testing machine. The test results showed that PVA fiber could improve the tensile strength and ultimate tensile value of concrete, lower its compressive elastic modulus and drying shrinkage, restrain its early plastic shrinkage and drying shrinkage cracks, reduce its cracking temperature and improve the crack resistance property of concrete, moreover, the effect of long PVA fiber was better.

Abstract: Using corundum particles and fine powder, α-Al₂O3 powder, silicon powder, aluminum powder and some additives as raw materials, β-Sialon bonded corundum composite was synthesized in-situ at the nitrogen atmosphere. The influence of Z value in sialon phase and sintering temperature on physical properties, mechanical properties, thermal shock resistance and anti-oxidation performance of β-Sialon bonded corundum composite was investigated. The results indicate that the comprehensive properties of β-Sialon bonded corundum composite is excellent on condition that Z=2.75, sintering temperature is 1500°C at nitrogen atmosphere.