Advanced Materials Research Vols. 152-153

Abstract: Use of an air filter material combined with antibacterial agents is one of the most effective methods to resolve the problem of air filter contaminated by pathogenic microbes. ε-Polylysine and Natamycin are two biogenic antimicrobials that have been widely applied in recent years because of their high antibacterial efficiency, harmlessness to human body and environmental friendliness. In this paper, a novel antibacterial air filter material was prepared by immobilizing ε-Polylysine and Natamycin onto fiberglass high efficiency air filter media by acrylate adhesive bonding. The mechanical properties, aerosol filtration properties, and antibacterial properties were then evaluated. An improvement in the mechanical properties of the material prepared was seen compared to the untreated filter media. The filtration efficiency of the material prepared for particle aerosols and bioaerosols both greater than 99.997%. Antibacterial efficiency of the material prepared against Staphylococcus aureus and Escherichia coli in suspensions were both greater than 99.99% compared to the untreated filter media. The anti-mildew effect against Aspergillus niger in suspension was strong compared to the untreated filter media. Antibacterial efficiency of the material prepared against bacteria in bioaerosols was greater than 99.99%. Observed with Scanning Electron Microscope, most bacteria on antibacterial filter media appeared to be dead. Thus, antibacterial air filter material prepared by immobilizing bio-antimicrobials on fiberglass had a strong inhibitory effect against gram-positive bacteria, gram-negative bacteria and fungi, with no impairment of the intrinsic properties. This kind of material appears to be promising for application in air cleaning and biological protection fields.

Abstract: Surface modification of plasma treatment was employed to improve the interface between silk fibroin (SF) powder and polyurethane (PU) in preparation of SF powder/PU blend film. Morphology analysis showed that plasma-treated blend film became dense and compact. The water vapor permeability of blend film from treated powder was significantly lowered. Plasma-treated artificial blood vessel was nearly waterproof, of which the water permeability was about 1/40 of the original value. Correspondingly, the compliance of plasma-treated vessel was enhanced remarkably, indicating it has better elasticity and flexibility which is more suitable for its application in tissue engineering.

Abstract: Ohmic contact testing structures have been prepared on n type 4H-SiC layer with different multiple-layer metal, such as Ti/Ni/Au, Cr/Ni/Au and Ni/Ti/Au by magnetic sputter process. Special contact resistances about 10-6cm2 are achieved using TLM measurements. The composition of the alloy areas have been analyzed through XPS and AES, and the results show that the C vacancies induced by carbonides formation are important for ohmic contacts of Ti and Cr to SiC. However, the Ni/SiC structures need a relatively higher alloy temperature, so that the out diffusion of C atoms can offset the lack of Si in the top layer of SiC.

Abstract: A new microorganism immobilization method involving preparation and gelation of waterborne polyurethane (WPU) was developed. The WPU prepolymer was synthesized by polyether polyol, isophoronediisocyanate (IPDI), 2-hydroxylethyl methacrylate (HEMA) were prepared by radical polymerization. The feasibility of the proposed immobilization method was tested by nitrifying bacteria. The effects of WPU prepolymer and gelation process on the activity of nitrifying bacteria were investigated by relative respiratory activity. The microbial growth and distribution of immobilized nitrobacteria were observed with a scanning electron microscope (SEM) before and after acclimation. The results verified that the waterborne polyurethane is an ideal microbial immobilization support material and has a great potential for a variety of biological wastewater treatment applications.

Abstract: The adsorption and desorption efficiencies on flavonoids and polyphenols from Eucommia ulmoides leaves by different resins were investigated, and the most suitable resin for preparation of Eucommia ulmoides leaves antioxidant was chosen. Then the crude extract of Eucommia ulmoides leaves was adsorbed by resin, and the resin was eluted by 20%, 40%, 60% and 80% (in volume) ethanol elution solution, and then the antioxidants were gotten. The flavonoids and polyphenols in the antioxidants were tested for content. The antioxidation activity in vitro was studied by testing the scavenging capacities on HO•, O2-• and DPPH•. The result showed: the 20%, 40% and 60% ethanol elution solution had good scavenging capacities on HO•, O2-• and DPPH•, and there was a good correlation between the contents of flavonoids and polyphenols and scavenging efficiency on each free radical; the antioxidation activities in vitro of the antioxidants was related to flavonoids and polyphenols, and the polyphenols was the leading working material; there was more polyphenols in 20% ethanol elution solution, and more flavonoids in 60% ethanol elution solution, so different antioxidant on different component content could be gotten by collecting different elution solution.

Abstract: We presented a fast, specific, and sensitive DNA sensing system, which composed of a CdTe/Fe3O4 magnetic core-shell quantum dots (energy donor), a commercial quencher (BHQ2; energy acceptor), and a designed single strand Toxoplasma gondii DNA. The designed single strand Toxoplasma gondii DNA was applied to link the energy donor and acceptor, and target DNA was detected based on mechanism of fluorescence resonance energy transfer. The CdTe quantum dots, Fe3O4 magnetic nanoparticles, CdTe/Fe3O4 magnetic core-shell quantum dots, and sensing probe were step-wisely prepared. Properties of synthesized quantum dots were investigated by transmission electron microscopy, fluorescence spectrum, nano zeta potential and submicron particle size analyzer, and X-ray diffraction, respectively. Specificity and sensitivity of sensing probe was determined by measuring the recovery of fluorescence intensity. The obtained sensing probe with magnetic properties can be simply separated or concentrated from the hybridized solution with a common magnet. The resulting data revealed the sensing system was successfully fabricated, and which has high sensitivity and specificity.

Abstract: This study tested four types of fireproof and stuffing materials, including firestop sheets, silicone fire barrier sealant, mineral wool batt, and double agent fire barrier foam, on through-floor pipes and walls. Based on the specifications of the American society for testing and materials (ASTM) E84, a 10 min substrate surface burning test was conducted to test fireproof and stuffing materials. The results indicated that the level of fireproof material substrates reached the level of class A in ASTM E84. Combination methods A and B were tested by 180 min heating for specimens, according to the ASTM E814 standard temperature-time (T-t) heating curve, followed by the water spraying test. The results showed that methods A and B have 180 min of fire prevention effects (F rating), and method B can achieve 180 min of heat prevention effects (T rating).

Abstract: KMnO4 and MnSO4 were used to prepare MnO2 nanowires for supercapacitors hydrothermal synthesis method. Scanning electron microscope (SEM), N2 adsorption-desorption and X-ray diffraction (XRD) were used to analyze the as prepared MnO2. Electrochemical performance of MnO2 was characterized by cyclic voltammetry and galvanostatic charge/discharge. The results showed that the nanowires were α-MnO2 with a diameter of 30 to 40 nm. The specific surface area and mean pore diameter was 164.5 m2g-1 and 3.1 nm, respectively. In an electrolyte of 1 molL-1 (NH4)2SO4, the MnO2 had typical capacitive characterization in the potential region of –0.4～0.5V(vs. SCE). At a current density of 10 mAcm-2, a specific capacitance of 466 Fg-1 was achieved. Supercapacitors based on the nanowires exhibited high cycling efficiency

Abstract: The grade of MgO of crude improves to 63.22% from 61.33% using brucite in liaoning province as the material by winnowing. The surface of Mg(OH)2 flame retardant is treated with four kinds of coupling agent，they are silane172，silane151，titanate NT-105 and composite coupling agent（silane172 being 66.7%,and zinc stearate being 33.3%）on the condition of usage of coupling agent being 0.5%、1.0%、1.5% and 2.0%，activating time being 3、6、9 and 12min，and the specific surface area，tensile strength，rate of absorbing water and oxygen index are measurated．The results showed the silane172 at the dosage of ≤1.5％, activating time 6－9min is feasible．Quality of its products can be comparable with synthetic products. Natural brucite is the ideal material for flame-retardant products．

Abstract: The vacuum flat bed filter is important equipment for the cold strip rolling because the surface quality of cold rolled strip is paid more attention by customer. In the paper, the function, mechanical structure and operation modes of the vacuum flat bed filter for cold strip rolling mill are introduced. The control logic of emulsion liquid level in the filter is discussed. The filter fabric running modes are designed. The control system for vacuum filter is developed based on PCS7 software and S7-400 PLC hardware of SIMENS.