scholarly journals Effect of harvest on MTE calculated by single step process for stochastic population model under Allee effect

2019 ◽  
Author(s):  
Çağatay Eskin ◽  
Özgür Gültekin
Keyword(s):  
Population Model ◽  
Allee Effect ◽  
Single Step ◽  
Step Process ◽  
Stochastic Population Model

scholarly journals Dynamics of a stochastic population model with Allee effect and jumps

2022 ◽  
Author(s):  
Rong Liu ◽  
Guirong Liu
Keyword(s):  
Growth Rate ◽  
Global Existence ◽  
Attack Rate ◽  
Population Model ◽  
Noise Intensity ◽  
Allee Effect ◽  
Global Attractivity ◽  
Stability In Distribution ◽  
Stochastic Population Model ◽  
Persistent In Mean

This paper is concerned with a stochastic population model with Allee effect and jumps. First, we show the global existence of almost surely positive solution to the model. Next, exponential extinction and persistence in mean are discussed. Then, we investigated the global attractivity and stability in distribution. At last, some numerical results are given. The results show that if attack rate $a$ is in the intermediate range or very large, the population will go extinct. Under the premise that attack rate $a$ is less than growth rate $r$, if the noise intensity or jump is relatively large, the population will become extinct; on the contrary, the population will be persistent in mean. The results in this paper generalize and improve the previous related results.

scholarly journals On stochastic population model with the Allee effect

2010 ◽  
Vol 52 (1-2) ◽  
pp. 370-379 ◽  
Author(s):  
Marija Krstić ◽  
Miljana Jovanović
Keyword(s):  
Population Model ◽  
Allee Effect ◽  
Stochastic Population Model

scholarly journals Single Step Process for Crystalline Ni-B Compounds

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1259 ◽  
Author(s):  
Mahboobeh Shahbazi ◽  
Henrietta Cathey ◽  
Natalia Danilova ◽  
Ian Mackinnon
Keyword(s):  
Single Phase ◽  
Single Step ◽  
Transformation Mechanism ◽  
Solid Reaction ◽  
Step Method ◽  
Step Process ◽  
Pressure Time ◽  
Autogenous Pressure ◽  
Higher Temperature ◽  
High Yields

Crystalline Ni2B, Ni3B, and Ni4B3 are synthesized by a single-step method using autogenous pressure from the reaction of NaBH4 and Ni precursors. The effect of reaction temperature, pressure, time, and starting materials on the composition of synthesized products, particle morphologies, and magnetic properties is demonstrated. High yields of Ni2B (>98%) are achieved at 2.3–3.4 MPa and ~670 °C over five hours. Crystalline Ni3B or Ni4B3 form in conjunction with Ni2B at higher temperature or higher autogenous pressure in proportions influenced by the ratios of initial reactants. For the same starting ratios of reactants, a longer reaction time or higher pressure shifts equilibria to lower yields of Ni2B. Using this approach, yields of ~88% Ni4B3 (single phase orthorhombic) and ~72% Ni3B are obtained for conditions 1.9 MPa < Pmax < 4.9 MPa and 670 °C < Tmax < 725 °C. Gas-solid reaction is the dominant transformation mechanism that results in formation of Ni2B at lower temperatures than conventional solid-state methods.

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