Papers by Keyword: Mechanism

Abstract: The extraction kinetics and mechanism of La (III) by P204-kerosine from phosphoric acid were investigated by constant interfacial cell with laminar flow. The effects of stirring speed, temperature, specific interface area on extraction rate were studied. The results indicated that a plateau region is appeared at the stirring speed of over 115r/min. The extraction apparent activation energy was calculated to be-13.40kJ/mol and the extraction process is controlled by a mixed mechanism of diffusion and chemical reaction. The rate equation of extraction was deduced. Under conditions of 25°C and interfacial area 19.64cm2, the extraction rate constant was 2.08×10-6 m·s-1·. Through the derivation of the reaction mechanism the reaction zone is at the liquid-liquid interface.

Abstract: Using the natural forsterite and Na2CO3 as a raw material, the forsterite lightweight material was prepared in Na2CO3 molten salt. The reaction between forsterite and Na2CO3 and sintering mechanism of forsterite were studied in the paper. The sintering temperature was 1000 °C, 1100 °C, and the holding time was 1 h, 3 h, 5 h, 7 h, 10 h, respectively. The sintered samples were characterized by XRD and SEM for their microstructure and phase composition analysis which determined the mechanism of the chemical reaction and sintering in the sintering process. The product of Na2MgSiO4 phase in In earlier period of the reactions promoted the rearrangement of particles of forsterite in the initial stage of sintering process. The sintering mechanism was mainly controlled by the diffusion mechanism.

Abstract: In this work, a series of theoretical methods were employed to investigate the reaction mechanisms of ribosomal peptide bond formation catalyzed by peptidyl transferase. For the studies described in this paper, reaction pathways and free energy barriers for the model reaction of the peptide bond synthesis were studied by performing Ab initio calculation. Two self-consistent reaction field (SCRF) methods were used to calculate of the whole reaction pathway. These results show that the present theoretical reaction mechanism is a potential and competitive one for the reaction modeling of the ribosomal peptide synthesis.

Abstract: The effects of fly-ash on dewatering of sewage sludge were studied according to sludge specific resistance (SSR), dehydrated speed, and moisture content of sludge cake as investigation indexes through single-factor experiments by contrasting to cationic polyacrylamide (PAM). The results showed that SSR kept decreasing with the rising of fly-ash dosage. When the dosage of fly-ash was 0.02 g/(ml sludge), SSR reduced by 65.2%. When the dosage of fly-ash was over 0.03 g/(ml sludge) adding with PAM, the dehydrated speed will be increased by three fourths. Through the analyses of Zeta potential, scanning electron microscope (SEM) observation, combined with the dehydration experiments, it was thought that the mechanism of fly-ash on dewatering of sewage sludge was that their particles evenly dispersed in sludge floc skeleton structure and thus decreased the SSR and improved the permeability of the sludge cake. The disposal of dewatering sludge and recycling approaches after fly-ash condition were also discussed. They can be used as landfill or as raw materials in building fields.

Abstract: The present domestic modifiers are mainly by-products of petroleum --- costing high and non-renewable, which lead to the difficulty in their wide use. This paper explores the mechanisms of purified diatomite, enhancing the stability of asphalt mixture under high temperature, low temperature or with water. At the same time, the paper makes analysis on the economy of project application, providing theoretical and economical references for spreading purified diatomite as a new modifier.

Abstract: By the methods of in-house experiment and theory analysis, the fracture initiation, stretch and interconnected mechanism of natural fracture is studied in the fracturing process of main fracture and branch fracture extending. The results have shown that, the hydraulic fracture in fractured formation is composed of a few main fractures in large size and many s secondary fractures in small size. The main fracture has the extending trend with the maximum crustal stress direction. The direction of sub fracture is network along the maximum crustal stress. The higher the degree of natural fractures, the difference between maximum and minimum crustal stress smaller. And the natural fracture is easier to form larger fracture. Fracture orientation and fracture width are determined by different combinations of natural fractures and the relative orientation with the maximum crustal stress.

Abstract: The emission in atmosphere results in global climates warm, reduction of emission is growing concern of many countries. The geological storage of is effective method to reduce emission. Because coal seam has strong absorption capacity for ,the coal seam can be used as geological storage reservoirs, and coal seam has such characteristics that coal seam is preference for absorption and postponement for absorption, injection into coal seam can enhanced coal bed methane recovery, -ECBM, because and compete and absorb in coal seam , displace , hence coal bed methane can be obtained by The geological storage of in coal seam,is a energy generated by methane from injection into coal seam, injection into coal seam can not only reduce emission and but also enhance coal bed methane recovery, that is important to environment protection and energy sustainable development.

Abstract: Biomass gasification is one of the most promising technologies to exploit energy from renewable biomass. In this paper, brief introduction of the mechanism of biomass gasification technology and the application status of biomass gasification was described in detail. The research progress of biomass gasification technology in China is reviewed. Finally, the features of these technologies are analyzed and the problems that the biomass gasification technology needs to solve and the research direction of this technology are pointed out.

Abstract: Electrostatic spinning is now recognized as a versatile and easily feasible method for the preparation of micro and nanofibrous materials. Because of their high specific surface area and highly porous structure electrospun materials can find application as wound dressings that provide good draining and good air permeability [. By adding various types of material or chemical modification in electrospun materials, we can prepare a polymer with excellent antibacterial properties of nanomaterials. Copper, an inorganic antibacterial agent, is also called the second silver. The antibacterial research of copper series attracted great concern in recent years. First, the paper introduced the progress and mechanism of electrostatic spinning of native cellulose and Cu (II) ion antimicrobial fibres, and then did a brief presentation of copper ion antibacterial fibers on the bases of electrostatic spinning of native cellulose.

Abstract: The classification and mechanism of the biofilm for treatment wastewater were introduced in this paper. Bio-contact oxidation, a typical biofilm process was described in detail. The example of treatment sewage of Heilongjiang University of science and technology proved that bio-contact oxidation process was more efficient for treatment sewage. It was considered as a wide range of application prospects.