Light particle properties

Second Quantized Description of a System of Noninteracting Spin Particles.—All the spin particles discovered thus far in nature have the property that particles and antiparticles are distinct from one another. In fact there operates in nature conservation laws (besides charge conservation) which prevent such a particle from turning into its antiparticle. These laws operate independently for light particles (leptons) and heavy particles (baryons). For the light fermions, i.e., the leptons neutrinos, muons, and electrons, the conservation law is that of leptons, requiring that the number of leptons minus the number of antileptons is conserved in any process. For the baryons (nucleons, A, E, and S hyperons) the conservation law is the... 

We are used to thinking of electrons as particles. As it turns out, electrons display both particle properties and wave properties. The French physicist Louis de Broglie first suggested that electrons display wave-particle duality like that exhibited by photons. De Broglie reasoned from nature s tendency toward symmetry If things that behave like waves (light) have particle characteristics, then things that behave like particles (electrons) should also have wave characteristics. 

When fluidized, the particles are suspended in the gas, and the fluidized mass (called a fluidized bed) has many properties of a liquid. Like a liquid, the fluidized particles seek their own level and assume the shape of the containing vessel. Large, heavy objects sink when added to the bed, and light particles float. 

An important factor in deriving 03 concentrations is the presence of aerosol particles, which also scatter light at 0.6 ixm. Thus, correction for their contribution to extinction at this wavelength must by applied to derive the ozone concentrations. This requires some assumptions regarding aerosol particle properties such as the size distribution, which is not known. It is also commonly assumed that the optical properties of particles do not change with altitude. Such problems introduce uncertainties into the calculation of the particle contribution (e.g., Steele and Turco, 1997a, 1997b Thomason et al., 1997 Fussen, 1998) and hence into the ozone concentrations extracted from such data. 

An increase in aerosol particles that can act as CCN can increase the number of cloud droplets and their size distribution, both of which can affect the light scattering properties of clouds and hence climate. We first briefly discuss the effects of clouds on climate and then the potential impacts of anthropogenic aerosols on the formation and properties of clouds. 

At the present time the electromagnetic scattering theory for a sphere, which we have called Mie theory, provides the only practical method for calculating light-scattering properties of finite particles of arbitrary size and refractive index. Clearly, however, many particles of interest are not spheres. It is therefore of considerable importance to know the extent to which Mie theory is applicable to nonspherical particles. To determine this requires generalizing from a large amount of experimental data and calculations. We summarize... 

Asano, S., 1979. Light scattering properties of spheroidal particles, Appl. Opt., 18, 712-723. ... 

Pinnick R. G., J. M. Rosen, and D. J. Hoffmann, 1973. Measured light-scattering properties of individual aerosol particles compared to Mie scattering theory, Appl. Opt., 12, 37-41. 

Many researchers have shown that incorporation of nanoscale dimension particles (inorganic fillers, nanotubes, nanofibers etc) into a polymer matrix enhances the mechanical properties of the polymer without significantly raising its density or sacrificing its light transmission property. For instance, the Toyota research groups... 

Einstein started this great development as early as 1905 by an almost unimaginable act of vision, when he concluded that the concept of such an electromagnetic wave does not suffice to explain important properties of light. He drew the revolutionary conclusion that there must exist light-particles, the photons, The particle-wave duality was born, Einstein recognized die fertility of his idea, but lie was never completely satisfied with the conceptual basis of quantum mechanics, The lack of complete causality and the frequent use of probability instead of certainty were always a matter of deep concern for him. 

Graaff R, Aamoudse JG, Zijp JR, Sloot PM A, Demul FFM, Greve J, Koelink MH. Reduced light-scattering properties for mixtures of spherical-particles a simple approximation derived from Mie calculations. Applied Optics 1992, 31, 1370-1376. 

In general, small/light particles can enhance heat transfer. The cluster formation in small/light particle systems contributes to the enhancement of hpc. Also the gas film resistance can be reduced by fluidizing with small particles [Wu et al., 1987]. When the temperature is lower than 400°C, the effect of bed temperature on the heat transfer coefficient is due to the change of gas properties, while hr is negligible. At higher temperatures, h increases with temperature, mainly because of the sharp increase of radiative heat transfer. 

Optical measurements of airborne combustion aerosols have been carried out for a number of years, usually with light scattering techniques. However, due to the particle size dependence of light scattering and the variable particle size distributions of smokes, it is extremely difficult to relate light scattering properties to particulate mass concentrations. The measurement of light absorption by particles can be directly related to particle mass if two conditions are met ... 

The core may be a solid or a liquid, or indeed a gas but this is unusual in the context of release applications. Hollow particles have found applications in other areas such as surface coatings, where they offer a high refractive index contrast with film itself, and therefore good light scattering properties. The shell... 

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