Comparative study on wheel-rail dynamic interactions of side-frame cross-bracing bogie and sub-frame radial bogie

Improving freight axle load is the most effective method to improve railway freight capability; based on the imported technologies of railway freight bogie, the 27 t axle load side-frame cross-bracing bogie and sub-frame radial bogie are developed in China. In order to analyze and compare dynamic interactions of the two newly developed heavy-haul freight bogies, we establish a vehi- cle-track coupling dynamic model and use numerical calculation methods for computer simulation. The dynamic performances of the two bogies are simulated separately at various conditions. The results show that at the dipped joint and straight line running conditions, the wheel-rail dynamic interactions of both bogies are basically the same, but at the curve negotiation condition, the wear and the lateral force of the side-frame cross-bracing bogie are much higher than that of the sub-frame radial bogie, and the advantages become more obvious when the curve radius is smaller. The results also indicate that the sub- frame radial bogie has better low-wheel-rail interaction characteristics.

Effects of Interaction between Axial and Radial Secondary Air and Reductive Intensity in Reduction Region on Combustion Characteristics and NO_(x) Emission of Coal Preheated by a Self-Preheating Burner

The study focused on the effects of the interaction between axial and radial secondary air and the reductive intensity in reduction region on combustion characteristics and NO_(x) emission in a 30 kW preheating combustion system.The results revealed that the interaction and reductive intensity influenced the combustion in the down-fired combustor(DFC) and NO_(x) emission greatly.For the temperature distribution,the interaction caused the position of the main combustion region to shift down as R_(2-12)(ratio of axial secondary air flow to radial secondary air flow) decreased or λ_(2)(total secondary air ratio) increased,and there was the interplay between both of their effects.As R_(3-12)(ratio of first-staged tertiary air flow to second-staged tertiary air flow)increased,the decrease in the reductive intensity also caused the above phenomenon,and the peak temperature increased in this region.For the NO_(x) emission,the interaction affected the NO_(x) reduction adversely when λ_(2) or R_(2-12) was higher,and the range of this effect was larger,so that the NO_x emission increased obviously as they increased.The decrease in the reductive intensity caused the NO_(x) emission increased under the homogeneous reduction mechanism,while was unchanged at a high level under the heterogeneous reduction mechanism.For the combustion efficiency,the interaction improved the combustion efficiency as λ_(2) increased when R_(2-12) was lower,while reduced it as λ_(2) increased excessively when R_(2-12) was higher.The proper decrease in the reductive intensity caused the combustion efficiency increased obviously,while was hardly improved further when the intensity decreased excessively.In this study,the lowest NO_(x) emission was only 41.75 mg/m^(3) without sacrificing the combustion efficiency by optimizing the interaction and reductive intensity.

Radial glia interact with primary olfactory axons to regulate development of the olfactory bulb

The developing olfactory system - merging of the periph- eral and central nervous systems： The olfactory system is responsible for the sense of smell and is comprised of a complex topographic map that regenerates throughout life. In rodents each olfactory sensory neuron expresses one of N 1,300 odorant receptors with the neurons being distributed mosaically within the epithelium. The axons of the sensory neurons do not maintain near-neighbour relationships and instead project to disparate topographic targets in the olfac- tory bulb within the central nervous system. The develop- ment of the targets relies on the intermingling of the sensory axons with the interneurons, glia and second order neurons of the olfactory bulb. Thus the formation of the olfactory system involves the coordinated integration of the axons of the peripheral olfactory sensory neurons with the cells of the olfactory bulb.