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H H Cho

Publications and source records attributed to H H Cho.

4 recordsLinked to original sources

Analysis of particle laden flow and heat transfer in cascade and rocket nozzle.

This paper presents results for the calculation of particle trajectories in a cascade and a rocket nozzle using a Lagrangian method. When the floating particles collide to the components, the component surface is damaged severely. The surface erosion rate is strongly dependent on a particle size, a particle impact angle and a surface material. For a compressor cascade, the particle impact rate increases proportionally with the flow inlet angle and the erosion rate on the pressure side surface of blade are related to the surface or coating materials. For a solid rocket nozzle, the particle free zone in the nozzle divergent section increases quickly with increasing particle size and the maximum heat transfer density occurs at the starting region of nozzle convergent section. The Al2O3 droplet breaks up around the nozzle throat due to the high velocity difference between the droplet and gas stream, resulting in the big change of particle free zone.

Journal Article↗

Inhibitory effect of mast cell-mediated immediate-type allergic reactions in rats by spirulina.

We investigated the effect of spirulina on mast cell-mediated immediate-type allergic reactions. Spirulina dose-dependently inhibited the systemic allergic reaction induced by compound 48/80 in rats. Spirulina inhibited compound 48/80-induced allergic reaction 100% with doses of 100-1000 microg/g body weight, i.p. Spirulina (10-1000 microg/g body weight, i.p.) also significantly inhibited local allergic reaction activated by anti-dinitrophenyl (DNP) IgE. When rats were pretreated with spirulina at a concentration ranging from 0.01 to 1000 microg/g body weight, i.p., the serum histamine levels were reduced in a dose-dependent manner. Spirulina (0.001 to 10 microg/mL) dose-dependently inhibited histamine release from rat peritoneal mast cells (RPMC) activated by compound 48/80 or anti-DNP IgE. The level of cyclic AMP in RPMC, when spirulina (10 microg/mL) was added, transiently and significantly increased about 70-fold at 10 sec compared with that of control cells. Moreover, spirulina (10 microg/mL) had a significant inhibitory effect on anti-DNP IgE-induced tumor necrosis factor-alpha production. These results indicate that spirulina inhibits mast cell-mediated immediate-type allergic reactions in vivo and in vitro.

Animals↗