They show explicitly that the necessary condition to realize a negative ( pulling ) optical force is the simultaneous excitation of multipoles in the particle and if the projection of the total photon momentum along the propagation direction is small, attractive optical force is possible.

With all the important work he accomplished in physics – the enunciation of Boyle's law, the discovery of the part taken by air in the propagation of sound, and investigations on the expansive force of freezing water, on specific gravities and refractive powers, on crystals, on electricity, on colour, on hydrostatics, etc.

The mechanics of eraillure formation are related to the propagation of a Hertzian cone of force through the cryptocrystalline matrix of the stone, but the particulars are poorly understood.

The laser light also tends to apply a force on particles in the beam along the direction of beam propagation.

According to Max Heindel's Rosicrucian writings, the etheric body, composed of four ethers, is called the " Vital Body " since the ether is the way of ingress for vital force from the Sun and the field of agencies in nature which promote such vital activities as assimilation, growth, and propagation.

He pointed out that in such a theory the gravitational force not only depends on the masses and their mutual distance, but also on their velocities and their position due to the finite propagation time of interaction.

" The use of a drill to create an " ampulla " of sorts and prevent the propagation of cracks through an important material is also used to protect airplane surfaces.

* propagation ( may comprise several elementary steps, as, for instance, reaction elementary acts, where the active particle through reaction forms another active particle which continues the reaction chain by entering the next elementary step ); particular cases are:

This " group velocity dispersion " is an important effect in the propagation of signals through optical fibers and in the design of high-power, short-pulse lasers.

Nowadays fracture propagation is the mechanism preferred by many geologists as it largely eliminates the major problems of moving a huge mass of magma through cold brittle crust.

It is commonly held to disprove light propagation through a luminiferous aether.

For example, the propagation of light through a prism results in the light ray being deflected depending on the shape and orientation of the prism.

In physics, radiation is a process in which energetic particles or energetic waves travel through vacuum, or though matter-containing media that are not required for their propagation.

Seismology () is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies.

It was Peddie who encouraged Watson-Watt to study radio, or " wireless telegraphy " as it was then known and who took him through what was effectively a postgraduate class of one on the physics of radio frequency oscillators and wave propagation.

* Anatomical transfer function, also called the head-related transfer function, the mathematical description of sound wave propagation through the human body

* In radio propagation by way of the ionosphere, the limiting frequency at or below which a wave component is reflected by, and above which it penetrates through, an ionospheric layer.

The propagation of light through optical fibre can take place via meridional rays or skew rays.

In general, magneto-optic effects break time reversal symmetry locally ( i. e. when only the propagation of light, and not the source of the magnetic field, is considered ) as well as Lorentz reciprocity, which is a necessary condition to construct devices such as optical isolators ( through which light passes in one direction but not the other ).

Figure 3 shows the propagation of light through a polarization independent isolator.

Path loss normally includes propagation losses caused by the natural expansion of the radio wave front in free space ( which usually takes the shape of an ever-increasing sphere ), absorption losses ( sometimes called penetration losses ), when the signal passes through media not transparent to electromagnetic waves, diffraction losses when part of the radiowave front is obstructed by an opaque obstacle, and losses caused by other phenomena.

* Transmittance, in optics, the propagation of a light wave through a medium

Unguided media provide a means for transmitting electromagnetic waves but do not guide them ; examples are propagation through air, vacuum and seawater.

Speculations exist as to whether or not certain Yersinia can also be spread via protozoonotic mechanisms, since Yersinia are known to be facultative intracellular parasites ; studies and discussions of the possibility of amoeba-vectored ( through the cyst form of the protozoan ) Yersinia propagation and proliferation are now in progress.

The propagation of quiet NaNs through arithmetic operations allows errors to be detected at the end of a sequence of operations without extensive testing during intermediate stages.

The advantage of Gray codes in these applications is that differences in the propagation delays of the many wires that represent the bits of the code cannot cause the received value to go through states that are out of the Gray code sequence.

Its mission is " to protect and enrich the flora of the Lake Baikal area and the world for people through public education, collection, propagation, research, and conservation of plants ".

The articles, finalised in 1571, were to have a lasting effect on religion in the United Kingdom and elsewhere through their incorporation into and propagation through the Book of Common Prayer.

It encourages facilities for standardization and propagation of the existing knowledge and its application through research in naturopathy throughout India.

The structural change caused by the implantation produces a surface compression in the steel, which prevents crack propagation and thus makes the material more resistant to fracture.

If the path length in the birefringent medium is sufficient, plane waves will exit the material with a significantly different propagation direction, due to refraction.

The key to TDR ’ s success is its ability to accurately determine the permittivity ( dielectric constant ) of a material from wave propagation, and the fact that there is a strong relationship between the permittivity of a material and its water content, as demonstrated in the pioneering works of Hoekstra and Delaney ( 1974 ) and Topp et al.

Electromagnetic wave propagation along the axis of the waveguide is described by the wave equation, which is derived from Maxwell's equations, and where the wavelength depends upon the structure of the waveguide, and the material within it ( air, plastic, vacuum, etc.

As, sometimes, a tube or another mechanical part has to cross a wall or floor that has special fire insulation material or that have special fire insulation resistance, it is needed to recover the original level of security of the fire system in case of maintenance, or to reach the designed level of security, so to avoid or delay the propagation of flame, smoke and heat accordingly.

The direction in which the propagation of the charge tends toward is usually constant throughout a pyroelectric material, but in some materials this direction can be changed by a nearby electric field.

Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light.

Another important mannerism of crack propagation is the way in which the advancing crack travels through the material.

A sensitiser is a powdered or fine particulate material that is sometimes used to create voids that aid in the initiation or propagation of the detonation wave.

In other systems, the crystalline structure of the material allows waves to propagate in one direction, while suppressing wave propagation in another direction.

Plants are produced using material from a single parent and as such there is no exchange of genetic material, therefore vegetative propagation methods almost always produce plants that are identical to the parent.

Fungicides can be used effectively by dip treating propagation material.

In 1968 Victor Veselago published a paper theorizing plane wave propagation in a material whose permittivity and permeability were assumed to be simultaneously negative.

The PC is also a material in which periodic inclusions inhibit wave propagation due to destructive interference from scattering from the periodic repetition.

So, it happens that the PC is the perfect bandgap material, because it allows no propagation of light.

Optical fibers have evolved into many forms since the practical breakthroughs that saw their wider introduction in the 1970s as conventional step index fibers and later as single material fibers where propagation was defined by an effective air cladding structure.

However, no matter how exotic the method of propagation, and no matter the material system, the sole driver for most that time has been the transportation of light from one point to another, whether by step-index confinement determined by simple Fresnel reflections or by coherent Fresnel reflections in bandgap fibers such as Bragg fibers.

Tissue growth and propagation studies indicate that epithelial cells adjust growth in response to presence of a foreign material.

The bandwidth of pulses generated by optical rectification is limited by the laser pulse duration, terahertz absorption in the crystal material, the thickness of the crystal, and a mismatch between the propagation speed of the laser pulse and the terahertz pulse inside the crystal.

Applications of this process include: clonal propagation of genetically uniform plant material ; elimination of viruses ; provision of source tissue for genetic transformation ; generation of whole plants from single cells called protoplasts ; development of synthetic seed technology.