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For insulating materials (both solid and liquid), [6] probing charge dynamics with microwaves is a part of dielectric spectroscopy.Amongst the conductive materials, superconductors are a material class that is often studied with microwave spectroscopy, giving information about penetration depth (governed by the superconducting condensate), [4] [7] energy gap (single-particle excitation of ...
Microwave brightness measurements do not directly measure temperature. They measure radiances in various wavelength bands, which must then be mathematically inverted to obtain indirect inferences of temperature. [1] [2] The resulting temperature profiles depend on details of the methods that are used to obtain temperatures from radiances. As a ...
The power consumption is drastically reduced compared to continuously operated Pirani gauges. The gauge's thermal influence on the real measurement is lowered considerably due to the low temperature threshold of 80 °C and the ramp heating in pulsed mode. The pulsed mode can be efficiently implemented using modern microprocessors. Disadvantages
Microwave signals are normally limited to the line of sight, so long-distance transmission using these signals requires a series of repeaters forming a microwave relay network. It is possible to use microwave signals in over-the-horizon communications using tropospheric scatter , but such systems are expensive and generally used only in ...
A microwave cavity or radio frequency cavity (RF cavity) is a special type of resonator, consisting of a closed (or largely closed) metal structure that confines electromagnetic fields in the microwave or RF region of the spectrum. The structure is either hollow or filled with dielectric material. The microwaves bounce back and forth between ...
The most common form of microwave radiometer was introduced by Robert Dicke in 1946 in the Radiation Laboratory of Massachusetts Institute of Technology to better determine the temperature of the microwave background radiation. This first radiometer worked at a wavelength 1.25 cm and was operated at the Massachusetts Institute of Technology.
The autoignition temperature or self-ignition temperature, often called spontaneous ignition temperature or minimum ignition temperature (or shortly ignition temperature) and formerly also known as kindling point, of a substance is the lowest temperature at which it spontaneously ignites in a normal atmosphere without an external source of ignition, such as a flame or spark. [1]
The most common ion gauge is the hot-cathode Bayard–Alpert gauge, with a small collector inside the grid. [1] A glass envelope with an opening to the vacuum can surround the electrodes, but usually the nude gauge is inserted in the vacuum chamber directly, the pins being fed through a ceramic plate in the wall of the chamber. Hot-cathode ...