Advanced Materials Research Vols. 152-153

Abstract: 3-hydroxybutyrate-co-4-hydroxybutyrate [P(3HB-4HB)] is one of polyhydroxyalkanoates which is biodegradable and biocompatible, and is one of the hot issues of the biodegradable materials research. But the degradation will occur at high temperature and shear rate. So P(3HB-4HB) is modified with PEG10000 by means of a mechanical blending. In this research, capillary rheometer and TGA are applied to investigate its rheological and thermal behaviors. The technology of melt spinning is also studied and the P(3HB-4HB)/PEG10000 fiber with a certain mechanical property is obtained successfully. Electronic velocimeter and electronic single end yarn strength tester are applied to investigate the mechanical property of the fiber. The result of TG indicates that the addition of PEG10000 improves the thermal stability of P(3HB-4HB). The result of capillary rheometer shows that P(3HB-4HB)/PEG10000 is pseudoplasticfluid. Because of the addition of PEG10000, the non-Newtonian index n of the P(3HB-4HB)/PEG10000 sample increases and the flow activation energy of the P(3HB-4HB)/PEG10000 sample decreases. The result of fiber strength test shows that the addition of PEG10000 has an impact on the mechanical property of the fiber and the lowest fiber strength appeared when PEG10000 content was P(3HB-4HB)/PEG=100/6. The moisture regain ratio increases with the content of PEG10000 rising. And when PEG10000 content is P(3HB-4HB)/PEG=100/2, the highest degree of orientation of fiber appears.

Abstract: The main causes of segment failure of diamond saw blade are studied in this paper. The segment material, the microstructure and the wear resistance of saw blade material were studied with scan electronic microscope, energy disperse spectroscopy, hardness meter, optical microscope. The results shows that the addition of alloying elements could refine grains, improve the holding force of matrix to diamond, enhance wear resistance of matrix to diamond, and decrease wear coefficient about 20%.

Abstract: The Ru/C nanocomposites with loading of 20wt% were prepared by ethylene glycol in the presence of XC-72. Carbon-supported Ru nanoparticles were decorated with Pt by spontaneous deposition method after Ru surface oxides were reduced in the hydrogen atmosphere at 180 for 2h. TEM indicated that the average particle size of catalyst was about 4nm with excellent dispersion and the XRD analyzing results showed that Pt had decorated on surface of Ru. The anti-poisoning ability was studied by pre-adsorbing CO striping voltammetric curves in 0.1M HClO4. Catalytic activities of the prepared Pt/Ru/C were studied by cyclic voltammetry in a solution of 0.5 mol/L CH3OH + 0.1 mol/L HClO4. The results showed that the oxidation current density was far more than 60wt% RuPt/C (E-TEK) and 20wt% Pt/C (Johnson Matthey). At the same time, the study also showed that the prepared catalyst not only had a higher catalytic activity to methanol, but also had lower Pt loading.

Abstract: Today’s global exploration of oil and gas leads to a range of highly corrosive environment that, in turn, require corrosion resistant high nickel content alloys for Oil Country Tubular Goods. Aimed at the problem of oil tube corrosion in environment with high content of H2S and CO2, the corrosion behavior of two nickel based alloys in 15%NaCl solution containing H2S/CO2 in high temperature and high pressure environments were researched. The pitting corrosion behavior of Ni-based alloys were investigated in FeCl3 solution by polarization curve and immersion test. The scanning electron microscopy(SEM), energy disperse spectroscopy(EDS) were applied to analyse the microstructure and corrosion performance of the samples. The results showed that the pitting-resistant of G3 was superior to Incoloy825.With the experimental temperature increasing, the corrosion rates increased and some slight corrosion pits appeared on the surface of Incoloy 825, Its maximum corrosion rate was 0.018mm/a. XRD showed that the corrosion films formed on nickel base alloys were consist of NiS, FeS and the oxides of Ni and Cr. The polarization curves showed that there were different corrosion behavior of two alloys, the anodic curve of G3 has an obvious passivation region, and there has higher pitting potential .

Abstract: First-principles calculations were performed to study the relative stabilities of YNi2 and YMgNi4.The calculated results show that YMgNi4 has the higher stability than YNi2, duing to stress relaxation and ionic contribution. The preferential stability of YMgNi4 has been confirmed by calculating elastic constants and melting points.The calculated results show that YMgNi4 has the larger bulk modulus and melting point than YNi2.

Abstract: Calcium phosphate/polyacrylate/alginate hybrid polymer microspheres with bovine serum albumin (BSA) embedded and coated on the surface were prepared with (NH4)2HPO4, sodium polyacrylate (SPA) and sodium alginate (SA) via Ca2+ crosslinking in inverse suspension. Rebinding behaviors of the microspheres were evaluated. The factors influencing the imprinting efficiency (IE) of imprinted microspheres were also studied, including the concentration of CaCl2, template content and pH values in rebinding solutions. Selectivity tests showed that the imprinted microspheres exhibited good recognition property for the template protein.

Abstract: A new poly(ester amide)s (PEA) derived from L-lactic acid and L- phenylalanine have been synthesized by melting copolymerization with p-toluenesulfonic acid (TSA), stannous chloride (SnCl2) as catalyst. The products were analyzed by NMR, FT IR. The effects of the content of L-phenylalanine on the copolymers structure were studied. Being the phosphate buffered saline (pH=7.2) as the degradation solution, it had been found that the degradation rate speed up with the increasing the content of the L- phenylalanine.

Abstract: Carbonated hydroxyapatite (CHA) was synthesized by solid-ion-exchange reaction of hydroxyapatite (HA) powders in CO2 atmosphere. The effects of the treatment atmosphere, temperature and time on carbonate substitution were investigated. The phase composition of the powders were characterized by X-ray diffraction and the content and type of the carbonate substitution were studied using Carbon-sulfur elemental analysis and Fourier transform infrared spectroscopy, respectively. The results show that the carbonate ion can enter the HA crystal lattice to form CHA giving priority to A-type by controlling the treatment temperature, atmosphere and time. Wet atmosphere treatment favors the reconstitution of hydroxyl and treatment in dry CO2 atmosphere favors the formation of A-Type substitution. The appropriate reaction temperature is 900 . Carbonate content increases with the treatment time and a further extension of treatment time tends to a slower increase of carbonate content.

Abstract: In an effort to seek poly(vinyl formal) (PVFM) foams based wound dressing pad material, a series of foamed PVFM materials have been synthesized under varied conditions. The influence of conditions on the properties of PVFM foam, such as mechanical properties, water absorption, pore structure and bulk density, is well discussed individually. It has been shown that both the reactant and acid catalyst affect the degree and speed of acetalization, therefore the mechanical properties, pores continuity and water absorption of the resultant sample. The addition of Na2CO3, surfactant and CMCNa are mainly influencing the porous structure as well as the mechanical properties and water absorption. One best sample with balanced properties is obtained. It possesses higher mechanical strength and water absorption while the other properties are similar, comparing with a commercial surgical PVFM sponge (YJ-1) currently used.

Abstract: To get higher rate of medicinal active ingredients of Tibetan medicine, the high-energy ultrasonic extraction technology is used. But the effect mechanism of acoustic cavitation to the chemical structure of the drugs is not clear yet. It is because that the theoretical and experimental researches are not enough. The research contents: the impact mechanism of HI ultrasound to the chemical structure of extracts should be tested comparing with other extraction technology, and the chemical composition of extracts with the different sound field parameters, media conditions, and process parameters. The methods: the chemical structures of active ingredients of extracts are detected by means of HPLC with the HI ultrasonic and reflux boiling extraction technologies; ultrasonic type, frequency and power density are repeatedly adjust respectively; the ③changes of the chemical constituents of the Tibetan medicine extracts are detected. The optimized acoustic parameters are obtained. Based on the findings above, the symmetrical collective and high intensity ultrasound is established. The results: the bio-pharmaceutical active ingredients of Tibetan medicine will not be compromised with the ultrasonic extraction; the ability of SCHIU extraction of Tibetan medicine is 3 to 4 times more than conventional ultrasound extraction with the same extracting rate.