The outgassing mass spectrum property with intense pulsed emission of the carbon nanotube(CNT) cathode is investigated on a 2 MeV linear induction accelerator injector by using the quadrupole mass spectrometer. The results show that the cathode has a capability of desorbing gases from the CNT cathode under pulsed high voltage. There are significant CO2, N2(CO) and H2 desorbing gases which play an important role in the formation of the cathode plasma. The mechanism of electron emission of CNT cathode is plasma-induced field emission, rather than explosive field emission, which is proved by analyzing the desorbed gases component.
In order to study the properties of the carbon nanotube(CNT) cathode with intense pulsed emission, the outgassing property of cathode is investigated on the 2MeV linear induction accelerator(LIA) injector. Results show that the cathode has a capability of desorbing gases from the CNT cathode under pulsed high voltage. The outgassing plays an important role in the formation of the cathode plasma. The amounts of outgassing for the several experiments are estimated to be 0.081.12PaL, the corresponding ratios between outgassing amount and electron number are roughly calculated to be in a range of 254203atoms/e- by numerical integral of pressure, showing that the cathode plasma is weakly ionized. The relationship between diode voltage, emission current density, outgassing amount, and the outgassing molecule number per electron are analyzed.
<p style='text-indent:20px;'>In this paper, we study a reaction-diffusion SEI epidemic model with/without immigration of infected hosts. Our results show that if there is no immigration for the infected (exposed) individuals, the model admits a threshold behaviour in terms of the basic reproduction number, and if the system includes the immigration, the disease always persists. In each case, we explore the global attractivity of the equilibrium via Lyapunov functions in the case of spatially homogeneous environment, and investigate the asymptotic behavior of the endemic equilibrium (when it exists) with respect to the small migration rate of the susceptible, exposed or infected population in the case of spatially heterogeneous environment. Our results suggest that the strategy of controlling the migration rate of population can not eradicate the disease, and the disease transmission risk will be underestimated if the immigration of infected hosts is ignored.</p>
Italy is the destination for migration and Libya is the main gateway for sending migrants by sea. Political instability in Libya due to the Arab Spring became fertile ground for smugglers to send thousands of irregular migrants from mainland Africa across the Mediterranean to Europe. The number of irregular migrants who come to cause problems for Italy. Italy is a country that is quite focused on resolving irregular migrant problems, but regulations regarding migrants are still said to be unsuccessful given the growing number of migrants. Migrants who arrive are often referred to as "Marocchini" or Moroccans. This research uses the concept of norms in constructivism. Norms have standards of behavior that contain prohibitions and recommendations of action. After the cessation of Operation Mare Nostrum, Italy continued to show consistency in complying with the laws of the sea and human rights, by continuing to carry out surveillance and rescue at sea. This was reinforced by the statement of the Italian Prime Minister, Matteo Renzi who was committed to making the problem in the Mediterranean a focus of foreign policy and migration became an important political agenda.
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