Monte Carlo Simulation as a Method to Determine the Critical Factors Affecting Two Strains ofEscherichia coliInactivation Kinetics by High Hydrostatic Pressure

2010 ◽  
Vol 7 (4) ◽  
pp. 459-466 ◽  
Author(s):  
Maria Consuelo Pina-Pérez ◽  
Magdalena M. García-Fernández ◽  
Dolores Rodrigo ◽  
Antonio Martínez-López
SPIN ◽  
2012 ◽  
Vol 02 (02) ◽  
pp. 1250007 ◽  
Author(s):  
ASHUTOSH SHARMA ◽  
SWETALI NIMJE ◽  
AKSHAYKUMAR SALIMATH ◽  
BAHNIMAN GHOSH

We have analyzed spin relaxation behavior of various II–VI semiconductors for nanowire structure and 2-D channel by simulating spin polarized transport through a semiclassical approach. Monte Carlo simulation method has been applied to simulate our model. D'yakonov–Perel mechanism and Elliot–Yafet mechanism are dominant for spin relaxation in II–VI semiconductors. Variation in spin relaxation length with external field has been analyzed and comparison is drawn between nanowire and 2-D channels. Spin relaxation lengths of various II–VI semiconductors are compared at an external field of 1 kV/cm to understand the predominant factors affecting spin dephasing in them. Among the many results obtained, most noticeable one is that spin relaxation length in nanowires is many times greater than that in 2-D channel.


2020 ◽  
Vol 8 (8) ◽  
pp. 596
Author(s):  
Hao Wang ◽  
Jiawang Chen ◽  
Yuhong Wang ◽  
Jiasong Fang ◽  
Yuping Fang

The ecosystem of the abyss is one of the fields that humans hardly know. The ultra-high hydrostatic pressure makes it very difficult to obtain abyssal organisms. Samples are often severely broken during recovery due to changes in environmental pressure, temperature, and other factors. Currently, there are no macro-organism samplers suitable for the abyss. The development of a pressure-maintaining sampler for the abyss is a prerequisite for abyssal ecosystem research. This paper mainly proposed a pressure-maintaining trapping instrument (PMTI) designed to work at a depth above 10,000 m. Unlike typical deep-sea equipment, this instrument is lightweight (about 65 kg in water). The instrument adopts a new structure, using a hollow piston as the sampling space and sealing the mechanism with O-rings at both ends of the piston, thus avoiding sealing methods such as ball valves and greatly reducing the weight of the equipment. The structure and working process of the instrument are described in detail in this paper. Meanwhile, in this paper, the movement resistance of the piston (mainly the resistance of the O-ring) is analyzed using a dynamic explicit method in Abaqus. The factors affecting the friction of the O-rings are analyzed via the method of orthogonal tests and ANOVA. In addition, high-pressure tests were conducted on key parts of the instrument, and the results showed that the instrument works well at 100 MPa.


Author(s):  
Ryuichi Shimizu ◽  
Ze-Jun Ding

Monte Carlo simulation has been becoming most powerful tool to describe the electron scattering in solids, leading to more comprehensive understanding of the complicated mechanism of generation of various types of signals for microbeam analysis.The present paper proposes a practical model for the Monte Carlo simulation of scattering processes of a penetrating electron and the generation of the slow secondaries in solids. The model is based on the combined use of Gryzinski’s inner-shell electron excitation function and the dielectric function for taking into account the valence electron contribution in inelastic scattering processes, while the cross-sections derived by partial wave expansion method are used for describing elastic scattering processes. An improvement of the use of this elastic scattering cross-section can be seen in the success to describe the anisotropy of angular distribution of elastically backscattered electrons from Au in low energy region, shown in Fig.l. Fig.l(a) shows the elastic cross-sections of 600 eV electron for single Au-atom, clearly indicating that the angular distribution is no more smooth as expected from Rutherford scattering formula, but has the socalled lobes appearing at the large scattering angle.


Author(s):  
D. R. Liu ◽  
S. S. Shinozaki ◽  
R. J. Baird

The epitaxially grown (GaAs)Ge thin film has been arousing much interest because it is one of metastable alloys of III-V compound semiconductors with germanium and a possible candidate in optoelectronic applications. It is important to be able to accurately determine the composition of the film, particularly whether or not the GaAs component is in stoichiometry, but x-ray energy dispersive analysis (EDS) cannot meet this need. The thickness of the film is usually about 0.5-1.5 μm. If Kα peaks are used for quantification, the accelerating voltage must be more than 10 kV in order for these peaks to be excited. Under this voltage, the generation depth of x-ray photons approaches 1 μm, as evidenced by a Monte Carlo simulation and actual x-ray intensity measurement as discussed below. If a lower voltage is used to reduce the generation depth, their L peaks have to be used. But these L peaks actually are merged as one big hump simply because the atomic numbers of these three elements are relatively small and close together, and the EDS energy resolution is limited.


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