Papers by Keyword: Mechanism

Abstract: The pure and Zr-doped BiFeO₃ thin films were fabricated on Pt/TiO₂/SiO₂/Si substrates by sol-gel method. The microstructural characterization revealed a phase structural transition from rhombohedral structure to tetragonal structure in Zr-doped BiFeO₃ thin films. Compared with pureBiFeO₃ thin film, the Zr-doped BiFeO₃ thin films showed better dielectric and leakage current characteristics. The mechanism associated with the enhancement of the electrical properties of the thin films is also discussed.

Abstract: This paper deals with the current transport mechanism of solid state photoelectrochemical cells of ITO/Cu₂O/PVCLiClO₄/graphite as well as the physical properties of a component of a device affecting its performance. The principle of operation used in the photoelectrochemical cells is presented. The device makes use of ITO films, Cu₂O films, PVCLiClO₄ and graphite films as photoanode, photovoltaic material, solid electrolyte and counter electrode, respectively. The device shows rectification. The J_sc and V_oc obtained at 100 mW cm² were 3.2 x 10^-11 mA/cm² and 0.92 V, respectively.

Abstract: The dynamic balancing of crank-slider mechanism was achieved with the guidance of the computer aided simulation-based optimization technique. Taking the reaction force of the rotary pair of connecting links and the input torque as optimization objective functions, the design optimization process was carried out with random-direction optimization method after determining the sensitive independent variables and their variation ranges based on the synthetical planning. The modal damping parameter of simulation model was optimized with the guidance of dynamic balancing experiment and the accuracy of simulation was also improved. Finally, by comparing the results from experiment and from optimization simulation, it is shown that optimization simulation could facilitate to instruct and implement the synthetical dynamic balancing for four-bar mechanism.

Abstract: This task studies the impacts and mechanisms of intermittent aeration and movement degree of membrane on the permeate flux in a submerged membrane system. The contents includes: Analysis of the effects of intermittent aeration on the membrane performance, modelling the experimental results and find out the mechanisms; Analysis of the effects of different movement degree of membrane on the permeate flux during the intermittent aeration process, modelling the experimental results and find out the mechanisms; Determination of the optimum membrane running conditions, including the most effective intensity of gas sparging, the most effective intermittent aeration cycle time and the most effective movement degree of membrane, etc. It shows that intermittent aerations between backwashing processes can significantly improve the membrane performance; the change of the movement degree (L/H),which means the ratio of the effective length and the effective vertical height) of membrane can affect the influences of intermittent aeration on the membrane performance significantly; the most effective intensity of gas sparging is 1.5L/h; the most effective intermittent aeration cycle time is 30min; the most effective movement degree of membrane is 1.07.The result of the research is good for the selection of operation condition and determination of running parameters of ultrafiltration membrane water supply process.

Abstract: Nitrate is a common groundwater contaminant and poses health and environmental threats. Reductive denitrification of nitrate by zero-valent iron was investigated in unbuffered solutions at 20 °C. Nitrate was effectively removed at low initial solution pH. The reaction was accompanied by the production and then disappearance of a small quantity of nitrite, suggesting that nitrite was the intermediate and subsequently further reduced. A rapid rise in solution pH was also observed during the reaction. At the initial pH of 4, a reduction of 90% in nitrate concentration from 60 to 7.0 mg/L at 60 min was observed. The extent of nitrate removal decreased with increasing solution pH within the tested range of 3 - 6, suggesting that the reaction was an acid-driven process. The extent of nitrate removal also increased with Fe dosage over the range of 5 - 20 g/L, as higher Fe dosages provided more reactive surfaces. It is proposed that protons participate in the nitrate reduction by Fe₀ via an initial reduction of protons to reduced hydrogen species followed by a subsequent reaction with nitrate. The hydrolysis of Fe corrosion products (e.g., ferrous ions) produces protons, in particular, near the surfaces of Fe, which drives the reaction to continue.

Abstract: The prepared Mn-Ce/CNTs catalyst was tested with Temperature-Programmed Desorption (TPD) in this experiment. The adsorption – desorption of NO, NH₃, O₂ on the surface of catalyst were studied and the mechanism of SCR was analyzed. The conclusions were as follows: NH₃was easily absorbed on the surface of Mn-Ce/CNTs catalyst for its significant competitive advantage; it can restrain the absorption of NO. The adsorption performance of NH₃ on catalyst surface was far greater than NO. When NO, O₂ adsorbed on the catalyst at the same time, the desorption amount of NO from catalyst significantly was less than the NO absorbed only. This shows that the O₂ can promote the adsorption of NO on the catalyst in SCR system.

Abstract: The anti-oxidation stability of rapeseed biodiesel (RME) was evaluated on an oxidation simulator set up by the author. The results showed that oxidative stability of RME was worse than that of petrodiesel by exhibiting higher acid values and peroxide values, as well as greater viscosity increases after oxidation. Furthermore, a conjecture was taken about the configurational changes and the oxidation mechanisms of unsaturated fatty acid methyl ester molecules in the oxidation process, according to the principles of free radical reactions and the results of both infrared and ultraviolet spectroscopic analysis. An idea was put forward that, during oxidation, cis-trans isomerization might occur in unsaturated fatty acid methyl ester molecules and conjugated double-bond might produce due to transfer of double-bond.

Abstract: The article deals with dynamic analysis of mechanism HR 3001 used at the lifting and transporting of various types of bodies or loads. It can be placed on the lorry so the manipulator becomes part of it. The goal of the analysis is to investigate the drive forces in hydraulic cylinders which are necessary for the lifting of load with specified mass. The modern methods used computer aid with the special software for analysis processing, which can simulate not only the motion of the mechanism, but they can define the position, velocity, acceleration, forces, moments and other parameters in every moments of time, but verification and mechanics laws understanding are necessary. The results serve for dimensioning of hydraulic cylinders at the designing of mechanism.

Abstract: Narciclasine (NCS) is a plant growth inhibitor isolated from the secreted mucilage of Narcissus tazetta bulbs, which is commonly used anticancer agent in human systems. Refer to the literatures in recent years, this article reviewed the anti-cancer effects of potential anticancer drugsNarciclasine, which induces apoptosis by activation of the death receptor and/or mitochondrial pathways in cancer cells. Narciclasine displays antitumor effects in apoptosis-resistant as well as in apoptosis-sensitive cancer cells by impairing the organization of the actin cytoskeleton.

Abstract: In this paper, the electrical analysis of emulsified asphalt and aggregate explains the reaction mechanism of the emulsified asphalt and aggregate. When emulsified asphalt and wet mineral aggregate contact each other, asphalt particles with a charge have chemical adsorption with aggregate at the surface of mineral aggregate, and asphalt particles are arranged on the surface of later quickly. Subsequently, asphalt of recycled mixture can be more cohesive after a series of process between emulsion and aggregate, such as demulsification and drying by distillation. A compact structure is formed by asphalt wrapping aggregate to make recycled mixture high strength. The mole - coulomb theory analyzes formation principle of emulsified asphalt cold recycled mixture strength. The strength of the recycled mixture mainly depends on the cohesion and internal friction among materials. In early stages, asphalt can not bonding because of water, which reduce the friction resistance of recycled mixture, and lead to the early strength of recycled mixture is small. After curing, the recycled mixture has the similar structure like hot asphalt mixture, which the cohesion and frictional resistance of recycled mixture became strong and the strength increased greatly. Besides, this paper expounds the dual role of cement that hydration reaction and of being active mineral powder in the process of emulsified asphalt cold recycled mixture strength formation.