China 
Africa 
Explore chapters and articles related to this topic
Introduction
Published in Robert E. Robson, Ronald D. White, Malte Hildebrandt, Fundamentals of Charged Particle Transport in Gases and Condensed Matter, 2017
Robert E. Robson, Ronald D. White, Malte Hildebrandt
The emergence of Boltzmann's equation in the latter part of the nineteenth century coincided with an era of great interest in electrical discharges in gases, though mutual recognition took some time. These investigations were motivated by the earlier observation of striations (alternating light and dark bands in the discharge) by Abria [5] (and more recently [6]), and culminated in the seminal drift tube experiments around the turn of the century and in the early 1900s. For example, Kaufmann and Thomson independently determined the elementary charge-to-mass ratio, e/m, which in turn led to Thomson's discovery of the electron, while the seminal experiment of Franck and Hertz confirmed Bohr's predictions of the quantized nature of atoms. As a result, there has been tremendous progress in science and technology, and it is not surprising that in the first three decades of the twentieth century, the field produced more than its fair share of Nobel laureates. Historical surveys of the “golden era” of drift tube experiments have been given by a number of authors, including Brown [7], Müller [8], Loeb [9], and Huxley and Crompton [10].
Short Review of Atomic and Semiconductor Theory
Published in Vijay B. Pawade, Sanjay J. Dhoble, Phosphors for Energy Saving and Conversion Technology, 2018
Vijay B. Pawade, Sanjay J. Dhoble
Two decades later, Dalton’s theory came into existence during the development of modern chemistry. Dalton carried out a most important investigation into the theory of atoms based on chemistry. Hence, the theory was named after Dalton, but its origin was not fully understood [4]. This theory was proposed when Dalton was researching ethylene, methane and analyzing nitrous oxide and NO2 under the direction of Thomas Thomson [5, 6]. After that he explained the law of multiple proportions based on the idea that the interactions of atoms consist of a chemical combination of definite and characteristic weight [7]. So, while during the study of the properties of atmospheric gases an idea of the atom was in Dalton’s mind, it was nothing more than a simple physical concept. He published his idea in 1805. He asked: “Why does not water admit its bulk of every kind of gas alike? This question I have duly considered and though I am not able to satisfy myself completely I am nearly persuaded that the circumstance depends on the weight and number of the ultimate particles of the several gases.” Some of the important points discussed by Dalton are as follows: 1.An element is made up of extremely small particles called atoms.2.They are identical in mass, size, and properties. Also, an atom of a different element has different mass, size, and properties.3.An atom can be neither created nor destroyed.4.Chemical comp ounds are formed by the combination of atoms of different elements.5.Atoms can be combined, separated or rearranged using a chemical reaction.
Investigation and correlation between surface modifications and field emission properties of laser-induced silicon plasma ion irradiated stainless steel
Published in Radiation Effects and Defects in Solids, 2022
Rizwan Amir, Shazia Bashir, Mahreen Akram, Muhammad Shahid Rafique, Mubashir Javed, Khaliq Mahmood, Wolfgang Husinsky, Shahzeb Ahmad
Laser-induced plasma is a versatile and beneficial tool for the generation of high-energy and high fluence ions (4–7). By controlling the laser parameters such as e.g. fluence, energy, wavelength, number of pulses, pulse duration and laser intensity, the energy and fluence of generated ions can be controlled. Thermal interactions, adiabatic expansion and Coulombic interactions are responsible for ion acceleration (8). The energy of nanosecond laser-generated plasma ions varies from a few keV to 100’s of keV. They can modify the hardness, wear resistance, electrical conductivity, chemical reactivity and field emission properties of the target material. These modifications are attributed to ion-generated defects, thermal spikes and displacement cascades (9, 10). For the evaluation of energy and fluence, different diagnostic techniques have been employed e.g. laser-induced breakdown spectroscopy, time of flight mass spectrometry, electrostatic ion energy analyzer, Langmuir probe and Thomson parabola technique (11). The space charge separation between the energetic electrons and the ions that lag prevents the electrons from completely escaping the plasma. Because the electrons are confined at the leading edge of the plume, a self-generated electrostatic field is formed which is responsible to pull the ions and enhance their kinetic energy (K. E.). The ions of laser-generated plasma gain energy by dipolar field and charge separation (12).
Analysis of guided wave propagation in functionally graded magneto-electro elastic composite
Published in Waves in Random and Complex Media, 2021
Hamdi Ezzin, Mohamed Mkaoir, Mohammad Arefi, Zhenghua Qian, Raj Das
For a transversely isotropic and linear piezoelectric-piezomagnetic solid, the 3D constitutive relations can be written as [30]: where , and are the strain, the electric field and the magnetic field, respectively: , and are the elastic, dielectric and magnetic permeability coefficients, respectively; , and are the piezoelectric, piezomagnetic and magneto electric coefficients, respectively. The 3D quasi-static coupled magneto-electro-elastic constitutive equations are given by the stress equilibrium equations without body forces of the layer, the Maxwell-Gauss equation without the electric charge density and the Maxwell-Thomson equation without electric current density, which are presented as follows: Similarly, we can write:
Development of a novel particle mass spectrometer for online measurements of refractory sulfate aerosols
Published in Aerosol Science and Technology, 2021
Yuya Kobayashi, Yu Ide, Nobuyuki Takegawa
Single-particle mass spectrometry by laser ablation/ionization techniques has been used to analyze the chemical composition of atmospheric aerosols in real time (e.g., Murphy and Thomson 1995; Noble and Prather 1996). These methods are characterized by the highly sensitive detection of both non-refractory and refractory sulfate aerosols; however, they do not provide quantitative estimates of the mass concentrations of sulfate. Currently available techniques for online quantitative measurements of sulfate aerosols include a particle-into-liquid sampler coupled with ion chromatography (PILS-IC; Weber et al. 2001) and an Aerodyne aerosol mass spectrometer (AMS; Jayne et al. 2000). These instruments have provided useful insights into the sources and processes of ambient aerosols. The PILS-IC can accurately quantify the total water-soluble sulfate aerosols but cannot specify their chemical form. The Aerodyne AMS is the most established type of thermal desorption aerosol mass spectrometer and has been widely used in the last two decades (e.g., Zhang et al. 2007). The AMS can quantify non-refractory sulfate aerosols by flash vaporization on a heated tungsten surface. The quantification capability of the Aerodyne AMS has been improved by the development of a new type of vaporizer (capture vaporizer) (Hu et al. 2017). While the Aerodyne AMS might be able to detect some refractory compounds by increasing the vaporizer temperature, it is not generally optimized to separately quantify non-refractory and refractory sulfate aerosols. The purpose of the present study is to describe a new particle mass spectrometer to separately measure non-refractory and refractory sulfate aerosols: a refractory aerosol thermal desorption mass spectrometer (rTDMS).