Search

The Ni-graphene composite coatings were prepared by electrochemical deposition method, using nickel sulfate and graphene as primary reagents. Pure Ni coatings, Ni-graphene coatings with N2H4 and Ni-graphene coatings without N2H4 were prepared from three different but similar electrolytes. The N2H4 added into the solution is for complexation with NiSO4 to settle the Ni ions. Graphene used in this work is characterized by TEM and HRTEM. The reaction of N2H4 with NiSO4 is characterized by XRD and optical graphs. The composite coatings’ morphology, structure and corrosion resistance were characterized by SEM and Potentiodynamic polarization test, respectively. The results show that well dispersed graphene–nickel coatings can be prepared with N2H4 in the electrolyte. By comparison with the situation that electrolyte without N2H4, graphene agglomerated at the surface of nickel coatings. The grain of the coatings prepared with and without N2H4 shows similar sizes. Ni-graphene coatings exhibit poor anticorrosion property by comparison with pure Ni coatings because of the defects (cracks and roughness on composite coatings with and without N2H4 in the solution, respectively) on the surface of graphene nickel coatings. These results provide a basis viewpoint for the further research of graphene-metallic composite coatings’ anticorrosion effect.

The difference between coal reservoir and conventional natural gas reservoir leads to difficulty for fracturing coal seam, also extremely low permeability in coal seam affects seriously the coalbed gas production. However, supercritical carbon dioxide has unique properties that promote pores and cracks, improve coal seam permeability and replace of CH4 in coal and rock seam. This paper researches on fracturing principle, generational capacity and carrying capacity, anti-reflection effect. At the sametime, based on the problem of change permeability in coal seam, the paper also analyes characteristics of coal reservoir and coalbed gas and combines with properties of supercritical carbon dioxide, which points out the feasibility and necessity that using supercritical carbon dioxide as fracturing carrier in coalbed gas exploitation realizes anti-reflection and increasing production.

The objective of this paper is to develop procedures for allocating resources to the activities of a given baseline schedule in order to minimize the number of extra precedence relations imposed by resource flows. Based on a proposed parallel resource flow generation scheme, two priority rule-based heuristics and a genetic algorithm are proposed. Finally, a set of computational experiments on standard benchmark datasets are presented to validate the heuristics.

Hierarchical structure is one of the most ubiquitous structures in various networked complex systems. In order to investigate the properties of the hierarchical structure, a deterministic hierarchical network model is first proposed. The statistical properties of the constructed networks are also discussed. The simulation results prove that the artificial networks simultaneously possess the small-world and scale-free properties well. This may be useful in furthering study of the topology properties of the hierarchical networks in real life.

The electrochemical behavior of catechol oxidation by H2O2which catalyzed by the copper binding methanobactin in aqueous solutions had been studied using cyclic voltammetry with a glassy carbon electrode. The contribution described the production and purification of a novel copper-binding peptide, methanobactin from Methylosinus trichosporium 3011, among which the copper binding methanobactin exhibited efficient horseradish peroxidase-like catalytic activity. The determinations of mimetic peroxidase activity in human/rat blood, garlic, onion and scallion serve as models for the proposed method. A comparison of the results with established classical analysis is satisfactory.

Methanobactin (mb) is a small copper-binding chromopeptide produced by methanotrophs. In this paper, a quantitative assay method for the content of mb was developed. The mb produced by Methylosinus trichosporium 3011growth with methane and methanol as carbon sources were detected from the culture supernatants by the CAS colorimetric assay at wavelengths 605 nm. The aim of this study was to evaluate the effect of copper ion on mb production by methane-growth and methanol-growth Methylosinus trichosporium 3011. The results of our experiments prove that Methylosinus trichosporium 3011 is able to utilize methanol as sole source of carbon and energy to produce mb. Cells grown on both methane and methanol exhibited differences in the accumulations of mb which were dependent on the concentration of copper (Ⅱ) present in the growth medium. An increase in the concentration of copper (Ⅱ) in the growth medium decreased mb content in the supernatant solutions. However, the mb was shown to exhibit maximal concentration at 0.5µmol/L copper (Ⅱ) with methanol as carbon source in contrast to the mb from cells grown on methane which as maximum concentration at 0 µmol/L copper (Ⅱ).

Methanotrophic physiology is strongly affected by the amount of bioavailable copper, which regulates the enzymes used by methanotrophs to oxidize methane. Methanobactin is a small peptide secreted by methanotrophic bacteria that binds copper outside of the bacterial cell. In this study, gold nanoparticles were firstly synthesized with citrate acid, followed by addition of methanobactin. Then as CuSO4was continuously added to the solution, we found a red shift in the Uv-vis absorption spectra. Meanwhile, for the mixture of methanobactin, 1,4-resorcinol and chlorauric acid, we also found an absorption at 540nm after 1h in dark. We presume that methanobactin has the bioactivity of protecting gold nanoparticles as well as delivering electron for the catalytic synthesis of gold nanoparticles. These molecules then go on to form gold nanoparticles. Gold nanoparticles can be seen with the naked eye, as they turn a gold solution from yellow/gold to a deep cranberry/red. The nanoparticles also display a characteristic absorbance of approximately 540 nm on absorption spectra.

To complete the explanation on the mechanism of the Poly-3-hydroxybutyrate (PHB) synthesis intracellular in methanotrophs, the role of nicotinamide adenine dinucleotide (NADH) in the PHB synthesis mechanism in Methylosinus trichosporium IMV 3011, which can utilize methane and methanol as source of carbon and energy to synthesize PHB, was studied. The study carried on by using carbon monoxide (CO) as NADH consumption substrate or using sodium formate as NADH production substrate. The results showed that NADH influenced the synthesis and accumulation of PHB intracellular to some extent. Especially, the yield of PHB would decrease to 13.5% (compared to normal yield of 21.3%) under NADH deficiency condition caused by CO at content of 20%. During the flask fermetation process of Methylosinus trichosporium IMV 3011, adding CO with certain centent (10%, v/v) or at right time (72h) into gas mixture would keep the NADH intrcelluar at appropriate concentration, which will be avialable for cell growth and PHB accumulation. The findings on the NADH will greatly contribute to the less expensive production of PHB by methanotrophs and promote the application in this field.

Methane-utilizing mixed culture HD6T was successfully cultivated in a brief non-sterile process using methanol as a sole carbon and energy source for the production of poly-β-hydroxybutyrate(PHB). Shake-flask experiments showed HD6T could grow well in the mineral salt medium with the addition of methanol exposed to the air directly. This non-sterile process and the use of cheap substrates (methanol) can reduce the production costs of PHB. It was found that HD6T grew better and PHB production in a more effective way with an initial liquid methanol concentration of 0.15%(v/v).The lag phase duration, the maximum growth rate, the biomass concentration and the PHB yield, for the optimal conditions were, respectively, 12.03h, 0.04h-1(OD600), 1.54g/l(dry weight), 0.424g/l(dry weight). Methane-utilizing mixed culture HD6T appears to be a promising organism for PHB production.

Hydrogenophaga palleronii LHJ38 can grow on naphthalene as sole carbon and energy source. The growth and naphthalene degradation curve of the strain were determined in biphase and monophase system respectively. The growth and naphthalene degradation capacity of cells obtained from oil phase and aqueous phase were compared carefully. The maximum biomass of 4.248g/L was obtained after cultivating 72h under the optimum conditions of 30 mL paraffin oil and 2g naphthalene in 1L mineral salt medium. In the biphase system, the naphthalene degradation capacity of Hydrogenophaga palleronii LHJ38 was higher more than 2 times than that in the monophase system. The naphthalene (2g/L) can be degraded completely in 132h when the concentration of cell was 2 mg dry weight cell/mL. The naphthalene degradation rate of cells obtained from oil phase was 2.7 fold as fast as that of cells obtained from aqueous phase.

HAS BEEN WITHDRAWN.