Ziyuan Ouyang

Acceleration of scattered solar wind protons at the polar terminator of the Moon: Results from Chang'E-1/SWIDs

[1]xa0We report accelerated particles observed by Solar Wind Ion Detectors (SWIDs) on ChangE-1 spacecraft close to terminator regions of the Moon. As the spacecraft crosses the terminator, a stream of ions with energy of ∼200eV/q are detected. As the spacecraft moves to the anti-subsolar point of the Moon, the energy of these ions increase by 600 ∼ 1500eV. This phenomenon occurs at north/south pole when IMF By component is dominant and negative/positive. It is proposed these particles are scattered solar wind protons, accelerated by the convection electric field of the solar wind and E × B drift in the ambipolar electric field at the flank of the lunar wake. This mechanism allows a new portion of solar wind protons to enter the central lunar wake, and provides a possibility to study the property of proton scattering at the dayside of the Moon.

Promotion effect of nanosized Pt, RuO2 and NiOx loading on visible light-driven photocatalysts K4Ce2M10O30 (M=Ta, Nb) for hydrogen evolution from water decomposition

Abstract Metal oxide photocatalysts K4Ce2M10O30 (M = Ta, Nb) capable of responding to visible light were synthesized by conventional high temperature solid-state reaction. The photocatalysts have an appropriate band gap energy ca. 1.8–2.3 eV and excellent chemical potential level to evolve H2 from aqueous solutions containing a sacrificial electron donor (Na2SO3) under visible light irradiation (λ>420 nm) without any co-catalyst. When they were loading with Pt, RuO2 and NiOx, the activities for evolving H2 were prompted markedly. By SEM and TEM investigations, it can be seen that these loading K4Ce2M10O30 (M = Ta, Nb) in diameter of about 10–30nm particles, especially the NiOx loading even formed double layered structure with metal nickel (Ni) and metal oxide (NiO). The reasons for the increasing activities after these loading electron migrating from the conduction band of K4Ce2M10O30 (M =Ta, Nb) to the Pt, RuO2 and NiOx nanoparticles, which function as H2 production sites on the surface of catalysts. The same phenomenon appears on the solid solution K4Ce2Ta10 –xNbxO30 (x = 0–10) with loading RuO2.

In-Situ Water Production by Reducing Ilmenite

Water is considered to be a fundamental condition of human’s colonization of the moon. The supply of oxygen is essential to the utilization of most lunar resources. According to the result of rough calculation, the cost for delivering oxygen from earth to moon for a ten-people lunar base will be nearly 5 to 9 billion dollars a year (Schrunk 1999; Taylor and Carrier 1993; Duke 2003). The cost is so high that water cannot be entirely supported by transportation from the Earth. Nevertheless, there are considerable mineral reserves in lunar soil. Compared to transporting water from earth directly, it is more economical to extract it from the lunar soil. The effects of meteorites, solar wind and cosmic ray make most of the lunar surface covered with a layer of lunar soil. The thickness of lunar soil is approximately 4~5 meters at the mare and >10 meters on the highland. The only practical source of water in the lunar soil is igneous minerals which contain typically 40 to 50% oxygen as oxides. The major minerals are ilmenite, anorthite, and olivine. All these oxides can provide oxygen and water to the lunar base even though some of them cannot be easily reduced. Compared with oxides of silicon, aluminum, titanium, calcium or magnesium, it is much more easily to extract oxygen from iron oxide such as ilmenite.

Condition of Solar Radiation on the Moon

Solar radiation is an exterior heat source of the Moon and represents a key resource with respect to returning to the Moon. It controls the variation of lunar-surface temperature during the lunation, and changes the thermal radiation properties of the lunar surface. In lunar Earth-based exploration, orbital exploration, and manned and unmanned lunar surface activities, solar radiation is an important factor which should be considered.