QCD evolution equations for parton densities

PCT No. PCT/JP97/01954 Sec. 371 Date Feb. 20, 1998 Sec. 102(e) Date Feb. 20, 1998 PCT Filed Jun. 9, 1996 PCT Pub. No. WO97/48294 PCT Pub. Date Dec. 24, 1997A flavor generation piece (12) incorporates a formed body (32) of a material containing a flavor substance. A heater (42) heats the flavor generation piece (12) without burning it, thereby generating a flavor. The heater (42) has a tank (46) mounted in a heat-insulating holder (44) to store a combustible gas. A combustion portion (52) for burning the combustible gas is disposed on the tank (46). Ignition or extinction of the combustion portion (52) is selected by a switch (58). The upper portion of the heat-insulating holder (44) forms a heat exchange duct (62) surrounding the combustion portion (52) and providing an exhaust path (64). An air pipe (74) is disposed to cross the heat exchange duct (62) transversely in the exhaust path (64). Heat exchange is performed between a fluid flowing in the exhaust path (64) and a fluid flowing in the air pipe (74). A socket (76) communicating with the air pipe (74) to detachably mount the flavor generation piece (12) is disposed on the outer side surface of the heat-insulating holder (44).