Μm in the context of Micro-

Gold leaf is gold that has been hammered into thin sheets (usually around 0.1 μm thick) by a process known as goldbeating, for use in gilding.

Gold leaf is a type of metal leaf, but the term is rarely used when referring to gold leaf. The term metal leaf is normally used for thin sheets of metal of any color that do not contain any real gold. Gold leaf is available in a wide variety of karats and shades. The most commonly used gold is 23-karat gold.

In medicine, public health, and biology, transmission is the passing of a pathogen causing communicable disease from an infected host individual or group to a particular individual or group, regardless of whether the other individual was previously infected. The term strictly refers to the transmission of microorganisms directly from one individual to another by one or more of the following means:

• airborne transmission – very small dry and wet particles that stay in the air for long periods of time allowing airborne contamination even after the departure of the host. Particle size < 5 μm.
• droplet transmission – small and usually wet particles that stay in the air for a short period of time. Contamination usually occurs in the presence of the host. Particle size > 5 μm.
• direct physical contact – touching an infected individual, including sexual contact
• indirect physical contact – usually by touching a contaminated surface, including soil (fomite)
• fecal–oral transmission – usually from unwashed hands, contaminated food or water sources due to lack of sanitation and hygiene, an important transmission route in pediatrics, veterinary medicine and developing countries.
• via contaminated hypodermic needles or blood products

Transmission can also be indirect, via another organism, either a vector (e.g. a mosquito or fly) or an intermediate host (e.g. tapeworm in pigs can be transmitted to humans who ingest improperly cooked pork). Indirect transmission could involve zoonoses or, more typically, larger pathogens like macroparasites with more complex life cycles. Transmissions can be autochthonous (i.e. between two individuals in the same place) or may involve travel of the microorganism or the affected hosts.

In infrared astronomy, the K band is an atmospheric transmission window centered on 2.2 μm (in the near-infrared 136 THz range). HgCdTe-based detectors are typically preferred for observing in this band.

Photometric systems used in astronomy are sets of filters or detectors that have well-defined windows of absorption, based around a central peak detection frequency and where the edges of the detection window are typically reported where sensitivity drops below 50% of peak. Various organizations have defined systems with various peak frequencies and cutoffs in the K band, including K′, and K_S, and K_dark.

Kinkaku-ji (金閣寺; Japanese pronunciation: [kʲiꜜŋ.ka.kɯ.dʑi], lit. 'Temple of the Golden Pavilion'), officially named Rokuon-ji (鹿苑寺; [ɾoꜜ.kɯ.oɲ.dʑi], lit. 'Deer Garden Temple'), is a Zen Buddhist temple in Kyoto, Japan and a tourist attraction. It is designated as a World Heritage Site, a National Special Historic Site, a National Special Landscape, and one of the 17 Historic Monuments of Ancient Kyoto. The temple is nicknamed after its reliquary (shariden), the Golden Pavilion (金閣, Kinkaku), whose top two floors are coated in 0.5 μm gold leaf. The current pavilion was rebuilt in 1955 after being destroyed in an arson attack.

The Moderate Resolution Imaging Spectroradiometer (MODIS) is a satellite-based sensor used for earth and climate measurements. There are two MODIS sensors in Earth orbit: one on board the Terra (EOS AM) satellite, launched by NASA in 1999; and one on board the Aqua (EOS PM) satellite, launched in 2002. Since 2011, MODIS operations have been supplemented by VIIRS sensors, such as the one aboard Suomi NPP. The systems often conduct similar operations due to their similar designs and orbits (with VIIRS data systems designed to be compatible with MODIS), though they have subtle differences contributing to similar but not identical uses.

The MODIS instruments were built by Santa Barbara Remote Sensing. They capture data in 36 spectral bands ranging in wavelength from 0.4 μm to 14.4 μm and at varying spatial resolutions (2 bands at 250 m, 5 bands at 500 m and 29 bands at 1 km). Together the instruments image the entire Earth every 1 to 2 days. They are designed to provide measurements in large-scale global dynamics including changes in Earth's cloud cover, radiation budget and processes occurring in the oceans, on land, and in the lower atmosphere.

Black carbon (BC) is the light-absorbing refractory form of elemental carbon remaining after pyrolysis (e.g., charcoal) or produced by incomplete combustion (e.g. soot).

Tihomir Novakov originated the term black carbon in the 1970s, after identifying black carbon as fine particulate matter (PM ≤ 2.5 μm aerodynamic diameter) in aerosols. Aerosol black carbon occurs in several linked forms. Formed through the incomplete combustion of fossil fuels, biofuel, and biomass, black carbon is one of the main types of soot particle in both anthropogenic and naturally occurring soot. As soot, black carbon causes disease and premature death. Because of these human health impacts, many countries have worked to reduce their emissions.

Jakobida is an order (sole order in the class Jakobea) of free-living, heterotrophic, flagellar eukaryotes in the clade Discoba. They are small (less than 15 μm), and can be found in aerobic and anaerobic environments. The order Jakobida, believed to be monophyletic, consists of only twenty species at present, and was classified as a group in 1993. There is ongoing research into the mitochondrial genomes of jakobids, which are unusually large and bacteria-like, evidence that jakobids may be important to the evolutionary history of eukaryotes.

Molecular phylogenetic evidence suggests strongly that jakobids are most closely related to Heterolobosea and Euglenozoa.

Betz cells (also known as pyramidal cells of Betz) are giant pyramidal cells (neurons) located within the fifth layer of the grey matter in the primary motor cortex. These neurons are the largest in the central nervous system, sometimes reaching 100 μm in diameter.

Betz cells are upper motor neurons that send their axons down to the spinal cord via the corticospinal tract, where in humans they synapse directly with anterior horn cells, which in turn synapse directly with their target muscles. Betz cells are not the sole source of direct connections to those neurons because most of the direct corticomotorneuronal cells are medium or small neurons. While Betz cells have one apical dendrite typical of pyramidal neurons, they have more primary dendritic shafts, which can branch out at almost any point from the soma (cell body). These perisomatic (around the cell body) and basal dendrites project into all cortical layers, but most of their horizontal branches/arbors populate layers V and VI, some reaching down into the white matter. According to one study, Betz cells represent about 10% of the total pyramidal cell population in layer Vb of the human primary motor cortex.

Iron powder has several uses; for example production of magnetic alloys and certain types of steels.

Iron powder is formed as a whole from several other iron particles. The particle sizes vary anywhere from 20-200 μm. The iron properties differ depending on the production method and history of a specific iron powder. There are three types of iron powder classifications: reduced iron powder, atomized powder, and electrolytic iron powder. Each type is used in various applications depending on their properties. There is very little difference in the visual appearances of reduced iron powder and atomized iron powder.

A dicing saw is a kind of saw which employs a high-speed spindle fitted with an extremely thin diamond blade or diamond wire to dice, cut, or groove semiconductor wafers, and glass, ceramic, crystal, and many other types of material.

The thickness of the cutting blades used varies with the material being cut, and is of about 20 μm to 35 μm when cutting silicon wafers. Japanese companies, such as DISCO Corporation and Accretech (Tokyo Seimitsu), account for about 90% of dicing saw sales. In the past, cutting 1/2 to 2/3 of wafer thickness was the mainstream; with large diameter wafers on dicing tape, full cut cutting is becoming mainstream.