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Spectroscopic ellipsometry
Spectroscopic ellipsometry is a nondestructive optical technique that determines film thickness and optical constants from wavelength-dependent polarization changes in obliquely reflected light, widely used in semiconductor manufacturing.
Spectroscopic redshift
A spectroscopic redshift is the displacement of a star's, galaxy's, or quasar's spectral lines from their rest wavelengths, expressed as z and about ten times more precise than photometric redshifts.
Spectroscopy
Spectroscopy is the study of physical systems by the electromagnetic radiation they absorb or emit, used to identify composition, measure motion, and analyze starlight from ground and space telescopes.
Spectrum
A spectrum is a record of how radiation's energy or intensity is distributed over wavelength or frequency, as when a prism spreads white light into a rainbow.
Spectrum (arena)
Spectrum Center, formerly Charlotte Bobcats Arena and Time Warner Cable Arena, is the 19,077-seat NBA arena in Uptown Charlotte, home of the Charlotte Hornets since 2005, renovated for $245 million and reopened October 2025.
Spectrum (functional analysis)
The spectrum, also called the operator spectrum, is the set of scalars λ for which T − λI has no bounded inverse, generalizing a matrix's eigenvalues.
Spectrum analyzer
A spectrum analyzer, also called a spectral analyzer, is a test instrument that displays signal power versus frequency, used in RF work such as wireless communications, radar, and EMC measurement.
Spectrum auction
A spectrum auction is a competitive bidding process by which a government regulator awards licenses to use radio spectrum, first held by the US FCC in 1994.
Spectrum Brands
Spectrum Brands Holdings is an American consumer products company in Middleton, Wisconsin, selling pet care, home and garden, and small appliance brands like George Foreman and Remington.
Spectrum hole
A spectrum hole is a licensed band of radio spectrum unused at a given time and place, available for opportunistic use by secondary cognitive radio users.
Spectrum imaging
Spectrum imaging is an electron microscopy technique, named from a 1989 paper by Jeanguillaume and Colliex, that records a full spectrum at every pixel to map composition and chemistry.
Spectrum Internet
Spectrum Internet is the residential and business broadband service sold by Charter Communications, offering speeds up to 1 Gbps across a 41-state footprint with unlimited data and no contracts.
Spectrum management
Spectrum management, also called spectrum planning or spectrum utilization, comprises the administrative and technical procedures that let radiocommunication services use the radio-frequency spectrum efficiently and free of harmful interference.
Spectrum Mobile
Spectrum Mobile is a mobile virtual network operator launched by Charter Communications in 2018 for Spectrum Internet subscribers, combining WiFi with Verizon's cellular network and serving 12.5 million lines by 2026.
Spectrum News
Spectrum News is Charter Communications' group of 24-hour regional cable news channels, begun as NY1 in 1992, renamed from Time Warner Cable News in 2016, with 35+ channels in nine states, Spectrum News+, and Spectrum Noticias.
Spectrum occupancy measurement
Spectrum occupancy measurement is the empirical determination of how much of a radio frequency band is actually in use, using energy thresholds to classify channels as occupied or idle.
Spectrum of a ring
The spectrum of a ring, written Spec(R), is the set of all prime ideals of a commutative ring R with the Zariski topology, forming an affine scheme.
Spectrum of a sentence
The spectrum of a sentence is the set of sizes of its finite models, introduced by Heinrich Scholz in 1952; first-order spectra are exactly the NEXPTIME sets.
Spectrum prediction
Spectrum prediction, also known as spectrum inference, is the task of forecasting the future occupied or free state of radio spectrum, a core function of cognitive radio systems.
Spectrum Range
Spectrum Range: a 2,430 m shield volcano in the Mount Edziza volcanic complex, Northern Cordilleran Volcanic Province, British Columbia, Canada; rhyolite domes over basaltic shield, vividly colored by solfataric alteration.
Spectrum sensing
Spectrum sensing is a cognitive radio detection method that decides whether a frequency band is occupied by a primary transmitter, so secondary users can use unused bands.
Spectrum-X
Spectrum-X is NVIDIA's Ethernet networking platform for AI data centers, announced in 2023, pairing Spectrum Ethernet switches with BlueField SuperNICs to deliver high bandwidth, low latency, and performance isolation for multi-tenant AI workloads.
Speculaas
Speculaas (Dutch, speculaas): a thin, crisp, spice-filled shortcrust biscuit from the Low Countries, molded in carved wooden boards for St. Nicholas (5-6 December); distinct from the cinnamon-only caramelized Belgian speculoos.
Specular microscopy
Specular microscopy is an ophthalmic imaging technique that photographs the corneal endothelium in vivo, measuring endothelial cell density for diagnosing corneal disease and planning corneal surgery.
Specular reflection
Specular reflection is mirror-like reflection from a smooth surface, obeying the law that the angle of reflection equals the angle of incidence, measured from the normal.
Speculation
Speculation, also called financial or market speculation, is buying or selling a financial asset to profit from price changes rather than from its use or fundamental yield.
Speculation on the disappearance of Amelia Earhart and Fred Noonan
Speculation on the 1937 disappearance of Amelia Earhart and Fred Noonan: crash-and-sink near Howland Island, the TIGHAR Nikumaroro castaway hypothesis, Japanese-capture theories, the 1940 Fiji bones, and recent Deep Sea Vision and Purdue expeditions.
Speculations About Jakob
Speculations About Jakob (German: Mutmassungen über Jakob) is the 1959 debut novel of German writer Uwe Johnson, following the unexplained death of East German railway dispatcher Jakob Abs.
Speculations about Mona Lisa
Speculations about Mona Lisa cover the sitter's identity (Lisa Gherardini vs alternatives), claimed earlier versions like the Isleworth Mona Lisa, the Prado copy, hidden-painting claims, smile and gaze perception studies, and medical iconodiagnoses.
Speculative decoding
Speculative decoding is an inference method for language models in which a smaller drafter proposes several tokens that the large target model verifies in a single pass, speeding generation.