Electron bombardment ion engine Patent

Electric rocket engine with electron bombardment ionization chambe

Lattice Expansion of (Ga,Mn)As: The Role of Substitutional Mn and of the Compensating Defects

We apply the density-functional technique to determine the lattice constant of GaAs supercells containing Mn_Ga, Mn_int, and As_Ga impurities, and use a linear interpolation to describe the dependence of the lattice constant a of Ga_{1-x}Mn_xAs on the concentrations of these impurities. The results of the supercell calculations confirm that Mn_Ga does not contribute to the lattice expansion. The increase of a is due to both Mn_int and As_Ga, that are both created in the as-grown (Ga,Mn)As in proportion to x, and that are most probably present in a remarkable amount also in the best annealed materials.Comment: 3 pages, 2 figures, presented at XXXIV Int. School. on the Physics of Semiconducting Compounds - Jaszowiec 2005, Ustron-Jaszowiec, Poland, June 4-10, 200

Disorder-Induced Effects in III-V Semiconductors with Mn

The substitution of Mn in the III-V diluted magnetic semiconductors leads to a strong electron scattering on impurities. Besides the features induced in the valence band by the hybridization with the Mn d-states, also the conduction band is affected by the absence of the Mn s-states at its edge. Also the high concentration of compensating donors modifies the band structure. This is shown on the absorption coefficient epsilon2(omega) of GaP doped with Mn and Se. The absorption evaluated by ab initio density functional calculations starts with a smooth tail and does not show the structure typical for III-V materials. We analyze these features and the role of the donors on model systems using the tight-binding coherent potential approach.Comment: 8 pages, 3 figures, presented at XXXI Int. School of Semiconducting Compounds, Jaszowiec 2002, Polan

Experimental studies with a mercury bombardment thrustor system

Performance tests of mercury electron bombardment ion engine syste

Plasma properties and performance of mercury ion thrusters

Plasma properties and performance of mercury ion thruster

The effects of problem-based learning in students reading comprehension for mastering the content and vocabulary acquisition

English reading comprehension is the most crucial language abilities in colleges where English is learned as a second language. A vigorous and powerful reading ability is certainly crucial in primary studies for students to accomplish in advanced education. However, the method in which they are instructed through lecture and paper pencil’s method were less relevant and effective in 21st Century. Students become passive, demotivated, bored, and feeling shy by the conventional teaching and learning. The purpose of this study is to examine the effectiveness of problem-based learning (PBL) on student’s English reading comprehension for mastering the contents and vocabulary acquisition. The study used a quantitative data where using an experimental pre-posttest design and the independent t-test and one-way ANOVA has been performed to test the hypothesis of the studies. The result indicated that there were statistically significant differences between the experimental and control groups for student’s reading comprehension for mastering the content and vocabulary acquisition using PBL. The results showed that the students who received PBL learning approached achieved higher performance outcome than student who is not received the PBL approach

Plasma characteristics of the electron bombardment ion engine

Plasma characteristics of electron bombardment ion engin