Analysis of Micro-scale Flame Structure of AP/HTPB Base Bleed Propellant Combustion

AbstractA complex multiple flame structure is formed during the combustion of AP/HTPB base bleed propellant. The AP monopropellant flame is concentrated in a thin zone above the burning surface of AP crystal to maintain self-sustained decomposition. Due to the low temperature near the burning surface, the diffusion between the decomposition products of AP and the pyrolysis products of HTPB occurs, and a partly pre-mixed diffusion flame structure-leading edge flame (LEF) is formed. The effects of pressure, chemical reaction rate and AP particle size on diffusion flame structure in the range from 20 atm to 100 atm are discussed. The Peclet number increases from 6.64 at 20 atm to 21.91 at 100 atm when AP particle size is 140 μm. The high temperature zone is blown away from the burning surface because the convective transport rate increases with the increase in Peclet number. The chemical reaction rate is enhanced and the diffusion mixing is inhibited as Damkohler number increases. The chemical heat release is more concentrated and the chemical reaction zone becomes narrow when Damkohler number changes from 330 at 20 atm to 4700 at 100 atm. When AP particle diameter is decreased to 60 μm, the diffusion time scale is reduced due to the reduced diffusion length scale. So the diffusion mixing is enhanced and a more pre-mixed flame is formed. The burning rate increases because the more pre-mixed heat release increases the heat feedback to the HTPB binder

The ρ\rho-meson longitudinal leading-twist distribution amplitude

In the present paper, we suggest a convenient model for the vector $\rho$-meson longitudinal leading-twist distribution amplitude $\phi_{2;\rho}^\|$, whose distribution is controlled by a single parameter $B^\|_{2;\rho}$. By choosing proper chiral current in the correlator, we obtain new light-cone sum rules (LCSR) for the $B\to\rho$ TFFs $A_1$, $A_2$ and $V$, in which the $\delta^1$-order $\phi_{2;\rho}^\|$ provides dominant contributions. Then we make a detailed discussion on the $\phi_{2;\rho}^\|$ properties via those $B\to\rho$ TFFs. A proper choice of $B^\|_{2;\rho}$ can make all the TFFs agree with the lattice QCD predictions. A prediction of $|V_{\rm ub}|$ has also been presented by using the extrapolated TFFs, which indicates that a larger $B^{\|}_{2;\rho}$ leads to a larger $|V_{\rm ub}|$. To compare with the BABAR data on $|V_{\rm ub}|$, the longitudinal leading-twist DA $\phi_{2;\rho}^\|$ prefers a doubly-humped behavior.Comment: 7 pages, 3 figures. Discussions improved and references updated. To be published in Phys.Lett.

The Analysis of Peasant Household's Credit Behavior

AbstractPeasant household's credit behavior not only affect the financial ability of the peasant household, but also influence the credit decisions of the rural financial institution, consequently impact on the development of the Chinese rural economic and the peasant household economic. This paper, based on the credit behavior of peasant household in the process of the Chinese rural economic development11Peasant household's credit behavior is the credit behavior under the comprehensive influence of the repayment capacity and willingness, in which repayment capacity is the key element., analysis the credit behavior game in rural credit and loan process between peasant households and rural financial institution, and the game among peasant households in rural joint warrant process. Finally, provides methods to improve the credit behavior of peasant household in credit game