Heating and acceleration of electrons in solar impulsive hard X-ray (HXR) flares are studied according to the two-stage acceleration model developed by Zhang for solar 3 Herich events. It is shown that electrostatic H-cyclotron waves can be excited at a parallel phase velocity less than about the electron thermal velocity and thus can significantly heat the electrons (up to 40 MK) through Landau resonance. The preheated electrons with velocities above a threshold are further accelerated to high energies in the flare-acceleration process. The flareproduced electron spectrum is obtained and shown to be thermal at low energies and power law at high energies. In the non-thermal energy range, the spectrum can be double power law if the spectral power index is energy dependent or related. The electron energy spectrum obtained by this study agrees quantitatively with the result derived from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) HXR observations in the flare of 2002 July 23. The total flux and energy flux of electrons accelerated in the solar flare also agree with the measurements.

A large molecular weight protein, alcohol dehydrogenase (ADH, 141 kDa), has been puri®ed from baker's yeast using reversed micelles formed with a cationic surfactant (cetyltrimethylammonium bromide, CTAB) using the phase transfer method. Various parameters, such as pH, ionic strength and contact time of the two phases in ADH forward and backward transfer were studied. The active ADH was successfully recovered after a full forward and backward extraction cycle. The recovery of ADH activity obtained was $90% and the puri®cation factor was 3.1 for the overall process.

Resonant heating of H, O +5 , and Mg +9 by parallel propagating ioncyclotron Alfvén waves in solar coronal holes at a heliocentric distance is studied using the heating rate derived from the quasilinear theory. It is shown that the particle-Alfvén-wave interaction is a significant microscopic process. The temperatures of the ions are rapidly increased up to the observed order in only microseconds, which implies that simply inserting the quasilinear heating rate into the fluid/MHD energy equation to calculate the radial dependence of ion temperatures may cause errors as the time scales do not match. Different species ions are heated by Alfvén waves with a power law spectrum in approximately a mass order. To heat O +5 over Mg +9 as measured by the Ultraviolet Coronagraph Spectrometer (UVCS) in the solar coronal hole at a region > ∼ 1.9R ⊙ , the energy density of Alfvén waves with a frequency close to the O +5-cyclotron frequency must be at least double of that at the Mg +9-cyclotron frequency. With an appropriate wave-energy spectrum, the heating of H, O +5 and Mg +9 can be consistent with the UVCS measurements in solar coronal holes at a heliocentric distance.