Papers by Keyword: Ionization

Abstract: Ionic plasma thruster is advanced propulsion technology utilized for space applications. Scientific research remains focused on the development of efficient and effective thruster technologies for space exploration. The technology of ionic plasma thruster is notable for its ability to achieve high specific impulse and fuel efficiency. This study outlines our study on plasma and endeavours to enhance Ionic Plasma Thruster through the utilization of innovative methodologies and materials. The experimental setup utilizes electrodes energized by a 1000 kV power module and Lithium-Ion batteries. The design of electrodes is to enhance the concentration of flow electrons for a significant ionization, after ionization the discharged particles (ions) causes the thruster to the system. In addition to ameliorate the thruster, neodymium magnets are strategically positioned, and to expedite the movement of ions and improve the ionization processes. This paper arrays our study and development on plasma ionization and ionic plasma thruster thorough examination of our experimental configuration, methods, and initial findings. Our ongoing research and development efforts aim to expand the technology of ionic plasma thruster, with the goal of enabling more efficient, cost effective and sustainable space exploration missions.

Abstract: Bulk mobility and dopant activation of implanted species into 4H-SiC plays a crucial role in the carrier conduction, blocking behavior, and channel properties of a 4H-SiC vertical power MOSFET. Nitrogen and phosphorus ion implantation became the norm as n-type dopants for 4H-SiC. Therefore, the doping and temperature behavior of both species in 4H-SiC needs to be well characterized. In this study, we report a comparison in electrical characteristics between nitrogen and phosphorus implanted 4H-SiC as a function of temperature for various doping levels. For this purpose, 4-point van der Pauw samples are prepared, resistivity and Hall measurements are conducted. We found that resistivities drop as temperature increases from 140 K with phosphorus having higher resistivities at all implanted doping concentrations. The carrier concentrations increase with increase of temperature, indicating incomplete ionization of dopants. Mobilities drop at low temperature due to increased impurity scattering, reaches a peak near 300 K and drops at higher temperature due to increased phonon scattering. From the obtained data, using a two-level charge neutrality equation, the activation percentage and ionization energies of dopants in hexagonal and cubic sites for both species are extracted and compared.

Abstract: Short circuit characteristics of 4H-SiC MOSFETs with different channel lengths are studied in this work. The peak drain-source current during the short-circuit period is measured. These results show that short channel devices has lower capability to sustain short-circuit condition. This work found an evident current tail after the gate turning off. Through the investigation with different device design, circuit condition and numeric simulation. The cause of the current tail is found to be due to the increased ionization of electron-hole pair as the junction temperature is elevated at long short-circuit condition.

Abstract: The photoluminescence of the near band gap emission of 10H-SiC is revealed for the first time and detected just below 3.0 eV. The crystallinity thus polytype of the sample is controlled with transmission electron microscope analyses and Laue diffraction. On the photoluminescence spectra up to eight sharp lines are associated to the non-phonon lines of the nitrogen bound exciton even if ten are expected in 10H-SiC. Phonon replicas of these non-phonon lines are observed at lower energy with energy separations similar than those in other hexagonal SiC polytypes. At moderate temperature free-exciton replicas are also observed which allow the determination of the excitonic band gap at 3020.6 meV, value in agreement with the hexagonality of 10H-SiC of 40%. The binding energies associated to the nitrogen bound-excitons are determined as well as the ionization energies of the nitrogen donors in the 10H-SiC polytype.

Abstract: The theory of thermal energy converters based on polyelectrolyte hydrogels has been developed. The possibility of providing the circulation of a fluid in the contour by controlled variations of the local value of concentrations of the mobile ions that cause an osmotic pressure gradient was shown. On the basis of the solution of motion equations of the mobile ions the numerical estimates of parameters of proposed type of circulation contour are given.

Abstract: Hydrogen occurs ionization under high temperatures and high pressures. Considered the interaction between the electrons and ions of fully ionized hydrogen plasma, and the translational motion of hydrogen ion obey Boltzmann distribution, Coulomb interactions between charged particles can be used Hartree-Fock integrals and described by approximants, and obtained the statistical mechanics model and equation of state of full ionized hydrogen plasma.

Abstract: Using the empirical formula with three free parameters recently proposed, ionization cross sections are given for the representation of cross sections for single ionization of free atoms from the ground stages by electron impact. Almost all experimental results can be approximated by this formula with 20% over the whole energy range between the threshold and 1 . All experimental results can be approximated with experimental error. The formula proposed is not suitable to regenerate the exact contour of fine structure in the ionization cross section curve. The probable error is estimated to be approximately 20%, but the error is larger than 40% and no fine structures are accounted for near the threshold.

Abstract: An effective acceptor level (E_A^eff) for representing the increased ionization ratio in extrinsically photon-recycled p-type GaN is proposed. E_A^eff at 300 K in the range of 0.1360.145 eV is found to reproduce current/voltage characteristics of transmission-line-model patterns formed with GaN p-n junction epitaxial layers and electrode spacing of 320 μm when the p-n diode current flowing through an 80×100-μm electrode is 90 mA. When E_A^eff is decreased from 0.160 eV to 0.145 eV, the on-resistance of 18×100-μm GaN bipolar transistors is predicted to be reduced by more than 50%.

Abstract: This paper presents the work principle and characteristics of the single pipe double cavity technology of positive and negative ions migration spectrum detection to terrorism and viper. The overall design of the double channel IMS detectors was discussed and the single pipe double cavity ion tube chemical and mechanical and electrical constitute integration is analysed. New application prospect for the future of the double channel of the IMS effective detection and prohibited item technology is presumed upon.

Abstract: This work consists of the numerical simulation of high enthalpy flows. The numerical model is governed by Euler equations and supplemented by the equations of the chemical kinetics modeling the phenomena of the chemical air components in a non-equilibrium state. The finite differences method is used for numerical simulations, the phenomena of a hypersonic flow one-dimensional reactive, non-viscous, chemical non-equilibrium is developed taking into account the physicochemical phenomena like the vibration, the dissociation of the diatomic molecules, the ionization of molecules and the formed atoms of chemical species to higher temperatures which appear behind a strong shock detached and evolve according to time in a relaxation range until to reach the equilibrium state. We are interesting in particular on the temperature effect in ionization of the atoms and the molecules.