Sentences with phrase «mean free path»

The low altitude molecules have decreased mean free path, higher collision rate, thus increased temperature.

The low altitude molecules have decreased mean free path, higher collision rate, thus an increase in temperature as you get closer to surface.

The former returns the bulk thermal conductivity, which masks the important mean free path distribution.

The range of the measurement depth can be determined by measuring a physical quantity called the inelastic mean free path (IMFP), which defines how far an electron can travel in a material while retaining its original energy level in a statistical sense.

«Optical imaging can generally work at the depth of 1 transport mean free path; roughly 1 mm of biological tissue.

«Usually, such transport phenomena are characterized by the so - called mean free path,» says Stefan Rotter.

In order for lateral confinement to be produced, the cross section of the structure must be much smaller than the «mean free path» of a phonon, or only a few to hundreds of nanometers depending on the material, Wang said.

Scaling approach is not applicable either, because the mean free path of an electron is much shorter than the actual ion source for NBI and an ion source with the size smaller than the mean free path has different characteristics.

As the mean free path can vary from phonon to phonon in a given material — from several nanometers to microns — the material exhibits a mean free path distribution, or range.

To study phonons» mean free paths, the researchers realized they would need a small heat source compared with the phonon mean free path to access the quasiballistic regime, as larger heat sources would essentially mask individual phonons» effects.

Chen and his colleagues came to their conclusion after devising an experiment to measure heat carriers» «mean free path» distribution in a material.

Creating nanoscale heat sources was a significant challenge: Lasers can only be focused to a spot the size of the light's wavelength, about one micron — more than 10 times the length of the mean free path in some phonons.

For each material, the researchers plotted a distribution of mean free paths, reconstructed from the heater - size - dependent thermal conductivity of a material.

A phonon's mean free path is the distance a phonon can carry heat before colliding with another particle; the longer a phonon's mean free path, the better it is able to carry, or conduct, heat.

The group sought to establish a framework and tool to measure the mean free path distribution in a number of technologically interesting materials.

«The important thing is, we have a spectroscopy tool to measure the mean free path distribution, and that distribution is important for many technological applications,» Zeng says.

For example, if an engineer desires a material with certain thermal properties, the mean free path distribution could serve as a blueprint to design specific «scattering centers» within the material — locations that prompt phonon collisions, in turn scattering heat propagation, leading to reduced heat carrying ability.

«With the average dwell time in an area or in a specific medium we have identified a quantity which is completely independent of the mean free path.

But when those two quantities are combined to calculate the overall time the average particle or wave spends inside the medium, then the mean free path drops out of the result entirely.

These quantities, the transmission time and the reflection time, heavily depend on the mean free path,» says Phillip Ambichl, PhD - student in Stefan Rotter's team and co-author of the paper.

Many important physical quantities depend on the mean free path — for instance the fraction of the light, which passes through semi-transparent glass.

In the case of the drunken sailor, the mean free path would be the average distance between the street lamps.

We can build a two - dimensional electron gas (2DEG) in which the mean free path exceeds 0.35 mm at low temperatures!

At these heights any remaining CO2 is basically irrelevant because the mean free path for absorption is of the order of kilometers.

This is true and Nasif Nahle has written a nice post about extinction length, mean free paths and absorption coefficients of CO2 and H20.

Just to give an example, the mean free path length of photons in the CO2 at its current density in the atmosphere is 48 meters.

The number of moles, the mass and the number of molecules per gram are the properties that have a major influence on the mean free path length of photons through the gases comprising the atmosphere.

Practically speaking, this is any volume that is many times the mean free path in the smallest linear dimension.