At ground level this decreases to about 1120-1000 watts / m < sup > 2 </ sup >, and by energy fractions to 44 % visible light, 3 % ultraviolet ( with the Sun at the zenith, but less at other angles ), and the remainder infrared.

At shorter wavelengths light is strongly absorbed by hemoglobin in blood, while at longer wavelengths water strongly absorbs infrared light.

At these temperatures ( 10 to 20 kelvins ) the radiation is in the microwave or infrared range of the spectrum.

At the same time, it has a very low heat conduction coefficient and can be made nearly transparent ( 15 – 20 % loss in a typical cooktop ) for radiation in the infrared wavelengths.

* At the atomic or molecular level, physical absorption in the infrared portion of the spectrum depends on the frequencies of atomic or molecular vibrations or chemical bonds, and on selection rules.

At the end of 1976, he accepted a Fellowship at the European Space Agency ’ s ( ESA ) Space Science Department at Noordwijk, Netherlands, where he worked as a research scientist in various airborne infrared astronomy programs.

At Texas A & M, Mims developed an infrared obstacle-sensing device and he experimented with it at the Saigon School for Blind Boys and Girls.

At MIT in the early 1960s, Ali Javan started a research project aimed at extending microwave frequency-measuring techniques into the infrared, he then developed the first absolutely accurate measurement of the speed of light.

At their core, laser tag systems typically use infrared signaling to track firing of the laser.

At night this process stops and air near the surface cools as the land loses heat by radiating in the infrared.

At the same time, infrared sensors detect heat signatures, such as those emitted by the engine of a vehicle.

At the same time, a few higher-powered ( 120 mW ) 404 – 405 nm " violet " laser pointers have become available which are not based on GaN, but use DPSS frequency-doubler technology from 1 watt 808 nm GaAlAs infrared diode lasers.

At such power levels, an IR filter for a DPSS laser may not be required as the infrared ( IR ) output is relatively low and the brightness of the visible wavelength of the laser will cause the eye to react ( blink reflex ).

At an elevation of, it is the third highest optical / infrared observatory in the world, and was the highest until the Indian Astronomical Observatory opened in 2001.

At the time of the design of ATM, 155 Mbit / s Synchronous Digital Hierarchy ( SDH ) with 135 Mbit / s payload was considered a fast optical network link, and many Plesiochronous Digital Hierarchy ( PDH ) links in the digital network were considerably slower, ranging from 1. 544 to 45 Mbit / s in the USA, and 2 to 34 Mbit / s in Europe.

At the regional cable television headend | headend, the TV channels are sent multiplexed on a light beam which travels through optical fiber trunklines, which fan out from distribution hubs to optical nodes in local communities.

At the optical node, the light beam from the fiber is translated back to an electrical signal and carried by coaxial cable distribution lines on utility poles, from which cables branch out to subscriber residences.

At the temperature at optical depth 2 / 3, the energy emitted by the star ( the original derivation is for the sun ) matches the observed total energy emitted.

* At an end face of an optical fiber, the angle between an input ray and the fiber axis.

At least several dB of optical power margin should be included in the optical power budget.

At those interfaces, a fraction of the optical signal is reflected back toward the source.

At the heart of Fresnel's wave theory is the Huygens-Fresnel principle, which states that every unobstructed point of a wavefront becomes the source of a secondary spherical wavelet and that the amplitude of the optical field E at a point on the screen is given by the superposition of all those secondary wavelets taking into account their relative phases.

At this point the preoccupations of the Cambridge psychologists and of Rivers were with the special senses: colour vision, optical illusions, sound-reactions and perceptual processes.

At this stage, some details concerning Wavelength Converting Transponders should be discussed, as this will clarify the role played by current DWDM technology as an additional optical transport layer.

At the quantum mechanical level, the information content of circular dichroism and optical rotation are identical.

At an early period, he had begun his optical researches, which were to have such important results in connection with photography.

At the lower end of a typical compound optical microscope there are one or more objective lenses that collect light from the sample.

At optical frequencies, in semiconductors the dielectric constant exhibits structure related to the band structure of the solid.

At least three episodes were filmed without a live studio audience: " The Bad Old Days ," which featured an extended flashback sequence that relied on optical effects that would have been impractical to shoot with a live audience in the studio ; " The Alan Brady Show Presents ," which required elaborate set and costume changes ; and " Happy Birthday and Too Many More ," which was filmed on November 26, 1963, only four days after President Kennedy's assassination.

At this point, the Q-switch device is quickly changed from low to high Q, allowing feedback and the process of optical amplification by stimulated emission to begin.

At the same time as Chappe, the Swedish inventor Abraham Niclas Edelcrantz experimented with the optical telegraph in Sweden.

At a wavelength of 6 cm ( 5 GHz frequency ), MERLIN has a resolution of 50 milliarcseconds which is comparable to that of the HST at optical wavelengths.

At Bell Labs, Dr. Jackson researched the optical and electronic properties of two-dimensional and quasi-two dimensional systems.

At times, he seems very much in the Degas camp of rich-colored realism ( especially his interior scenes ) and at other times, he shares the Impressionists ' commitment to " optical truth " and employs an impressionistic pastel-softness and loose brush strokes most similar to Renoir and Pissarro, though with a less vibrant palette.

At its most basic, photometry is conducted by gathering radiation in a telescope, perhaps passing it through specialized optical filters, and then capturing and recording the light energy with a photosensitive instrument.

At times, advanced techniques are employed with the goal of " undoing " the distortion of the optical path of the microscope, thus eliminating distortions and blurring caused by the instrumentation.

At other frequencies, more radiant intensity is required to achieve the same luminous intensity, according to the frequency response of the human eye.

At the lower end of the electromagnetic spectrum, about 20 Hz to about 20 kHz, are frequencies that might be considered in the audio range.

At radio and microwave frequencies, EMR interacts with matter largely as a bulk collection of charges which are spread out over large numbers of affected atoms.

At higher frequencies ( visible and beyond ), the effects of individual photons of the radiation begin to become important, as these now have enough energy individually directly or indirectly to damage biological molecules.

At high frequencies the capacitance begins to affect the inductor's behavior ; at some frequency, real inductors behave as resonant circuits, becoming self-resonant.

At higher frequencies, resistance and resistive losses in inductors grow due to skin effect in the inductor's winding wires.

At high frequencies, particularly radio frequencies ( RF ), inductors have higher resistance and other losses.

At VHF or higher frequencies an air core is likely to be used.

At frequencies offset from the strength of stimulated ( or spontaneous ) emission will be decreased according to the so-called " line shape ".

At higher frequencies, skin effect and proximity effect create additional winding resistance and losses.

At high frequencies, current travels near the surface of the wire because of the skin effect, resulting in increased power loss in the wire.

At frequencies much below VHF, ferrite circulators become impractically large.

At upper VHF and UHF frequencies, the metal skin of a car or aircraft can serve as a ground plane for whip antennas projecting from it.

At higher frequencies, the diode looks like an almost perfect ( very linear, even for large signals ) resistor.

At low frequencies, the charge can be removed and the diode turns off.

At higher frequencies, there is not enough time to remove the charge, so the diode never turns off.

At these frequencies, even small periodic driving forces can produce large amplitude oscillations, because the system stores vibrational energy.

At high frequencies, another effect called dielectric loss becomes significant, adding to the losses caused by resistance.

At high frequencies, current tends to run along the surface of the conductor.

At high enough frequencies 1 / ƒ noise is never dominant.

At higher frequencies, skin effect increases the effective resistance by confining the conduction to a thin layer of each conductor.

At high frequencies, a dielectric can have a significant resistive loss.

At low frequencies the field changes slowly enough to allow dipoles to reach equilibrium before the field has measurably changed.

At low frequencies, molecules in polar dielectrics are polarized by an applied electric field, which induces periodic rotations.