All articles starting with H

Heterodyne

Heterodyne, or heterodyning, is the process of combining two signals of different frequencies to produce sum and difference frequencies, the basis of the superheterodyne receiver.

Heterodyne detection

Heterodyne detection is a measurement technique that mixes a weak signal with a local oscillator at a slightly different frequency, recovering signals too weak or fast to measure directly.

Heterodyne interferometry

Heterodyne interferometry is an optical measurement technique in which a probe laser beam is mixed with a frequency-shifted reference beam, producing a beat signal whose phase encodes displacement.

Heterodyne spectroscopy is a coherent detection technique that mixes radiation with a slightly offset local oscillator, shifting it to a lower frequency where amplitude, frequency, and phase can be measured.

Heteroepitaxy

Heteroepitaxy is the growth of a single-crystalline film on a substrate of a different material, with the film's orientation dictated by the substrate; examples include GaN LEDs on sapphire and GaAs films on silicon.

Heteroflexibility

Heteroflexibility (also heteroflexible) is occasional same-sex attraction or behavior in an otherwise heterosexual orientation. Coverage includes the term's origins, the M-SOCS four-class system, prevalence estimates, sex differences, and critiques.

Heterogeneous base catalyst

A heterogeneous base catalyst is a solid material, such as calcium oxide, with basic surface sites that converts vegetable oils into biodiesel and can be separated, regenerated, and reused.

Heterogeneous computing

Heterogeneous computing combines different processor types, typically a CPU with GPUs, FPGAs, or ASICs, in one system so each runs the workloads it handles best.

Heterogeneous graph attention network

The heterogeneous graph attention network (HAN) is a graph neural network architecture, introduced by Xiao Wang and colleagues in 2019, that learns node representations from heterogeneous graphs.

Heterogeneous graph neural network

A heterogeneous graph neural network (HGNN) is a graph neural network extended to graphs with multiple node and edge types, applied to knowledge graphs, citation networks, and recommendation.

Heterogeneous integration

Heterogeneous integration is the assembly of separately manufactured semiconductor dies and chiplets, often made in different process technologies, into a single package delivering capabilities a monolithic chip cannot achieve.

Heterogeneous nuclear ribonucleoprotein

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a family of RNA-binding proteins that package newly made pre-mRNA in the nucleus and regulate splicing, export, stability, and translation.

Heterogeneous ribonucleoprotein particle

Heterogeneous ribonucleoprotein particles (hnRNPs): complexes of pre-mRNA (hnRNA) with about 20 canonical RNA-binding proteins (A1 to U) that package nascent transcripts, regulate splicing, export, and translation, and are implicated in ALS, cancer, and neurodevelopmental disorders.

Heterogenite

Heterogenite is a cobalt oxyhydroxide mineral, CoO(OH), the most abundant oxidized cobalt mineral and principal cobalt ore in the Katanga Copperbelt of the Democratic Republic of Congo.

Heteroglossia

Heteroglossia (raznorechie, разноречие) is Mikhail Bakhtin's term for the many competing socio-ideological voices within a single language, introduced in "Discourse in the Novel" (1934–35) and distinct from polyglossia, polyphony, and diglossia.

Heterojunction

A heterojunction is the interface between two different semiconductor materials, where band offsets control carrier flow; Herbert Kroemer's heterostructure work earned the 2000 Nobel Prize in Physics.

Heterojunction bipolar transistor

A heterojunction bipolar transistor (HBT) is a bipolar transistor whose emitter and base are made of different semiconductor materials, giving it far higher speed than ordinary transistors.

Heterojunction solar cell

A heterojunction solar cell, also called silicon heterojunction (SHJ) or HIT, is a crystalline silicon wafer solar cell passivated by thin amorphous silicon layers, reaching record efficiencies above 26%.

Heterokaryon

Heterokaryon: a fungal cell or mycelium holding genetically different nuclei in one cytoplasm; coined by Burgeff (1912), controlled by het loci, central to the parasexual cycle and dikaryons.

Heterokaryon incompatibility

Heterokaryon incompatibility, also called vegetative incompatibility, is a fungal self/nonself recognition process in which hyphal fusion between strains differing at het or vic loci triggers programmed cell death, blocking stable heterokaryon formation and limiting mycovirus transfer.

Heterokaryon incompatibility Het-C

Het-C is a heterokaryon incompatibility locus in Neurospora crassa (alleles OR, PA, GR) and Podospora anserina, encoding polymorphic proteins whose unlike combinations trigger programmed cell death of fused hyphae.

Heterokaryon incompatibility protein 6

Heterokaryon incompatibility protein 6 (HET-6, het-6 gene, NCU03533) is a Neurospora crassa HET-domain protein that, with un-24, triggers programmed cell death between genetically unlike fungal strains via OR and PA haplotypes.

Heteromyidae

Heteromyidae, the kangaroo rats, kangaroo mice, and pocket mice, is a New World rodent family of about 59 species in 6 genera, defined by external fur-lined cheek pouches, seed caching, and desert-adapted nocturnal foraging.

Heteromys

Heteromys, forest spiny pocket mice, is a genus of heteromyid rodents (Desmarest, 1817) with 17 species ranging from Texas to Ecuador; the only heteromyid genus in South America, absorbing the former genus Liomys.

Heteronormativity

Heteronormativity, coined by Michael Warner in 1991, is the assumption that heterosexuality and binary gender are the natural, normative standard. It differs from heterosexism (institutional privileging) and underlies health, education, and legal inequities for LGBTQ+ people.