Technology and the built world

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.

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 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.

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%.

Hetianhe Gas Field

Hetianhe Gas Field (和田河气田) is a carbonate gas field in the Tarim Basin of Xinjiang, northwest China, in the Taklamakan Desert and operated by PetroChina's Tarim Oilfield Company.

Hetzer

The Hetzer, formally the Jagdpanzer 38(t), was a German light tank destroyer of World War II, produced from April 1944 in Prague with 2,584 built by war's end.

Oct 22, 2026

Heungnyunsa

Heungnyunsa (흥륜사, 興輪寺) was a Buddhist temple in Gyeongju, the first founded in Silla and one of its seven sacred temples, abandoned in the early Joseon period.

Heuristic (computer science)

A heuristic in computer science is a technique that solves problems faster or more simply than complete methods, using rules of thumb at the price of no optimality guarantee.

Heuristic evaluation

Heuristic evaluation is a usability inspection method in which 3 to 5 expert reviewers check a user interface against a small set of usability principles, called heuristics.

Hever Castle

Hever Castle is a double-moated fortified manor in the Eden valley in Kent, a childhood home of Anne Boleyn, now a privately owned Grade I listed visitor attraction.

Oct 26, 2026

Hevo Data

Hevo Data (Hevo), founded 2017 by Manish Jethani and Sourabh Agarwal, is a San Francisco and Bangalore-based no-code ELT/ETL data pipeline SaaS with 170+ connectors, AWS-hosted, $43M raised.

Hewett Pipeline System

The Hewett Pipeline System is a set of North Sea gas pipelines that carried production from the Hewett field to the Bacton terminal until late 2020.

Hewlett-Packard

Hewlett-Packard Company (HP) was an American technology company founded in 1939 by Bill Hewlett and Dave Packard in a Palo Alto garage, seen as Silicon Valley's first.

Hex dump

A hex dump, also called a hexadecimal dump, is a byte-by-byte listing of binary data showing each byte as two hexadecimal digits, often with offsets and printable characters.

Hex key

A hex key, also called an Allen key or Allen wrench, is an L-shaped tool that drives screws and bolts with a hexagonal recess in the head.

Hexa-X-II

Hexa-X-II was the European 6G flagship research project, funded by the SNS Joint Undertaking under Horizon Europe, coordinated by Nokia and running from 2023 to 2025.

Hexagon AB

Hexagon AB is a Swedish technology company, headquartered in Stockholm, that develops precision measurement, positioning, and autonomous solutions for manufacturing, construction, aerospace, agriculture, and mining.

Hexagonal architecture (software)

Hexagonal architecture, also known as Ports and Adapters, is a software architecture pattern proposed by Alistair Cockburn in 2005 that isolates business logic from external technologies.

Hexamethylene triperoxide diamine

Hexamethylene triperoxide diamine (HMTD) is an organic peroxide primary explosive, first synthesized in 1885 and known as an improvised explosive used in the 2005 London bombings.

Hexapod machine tool

A hexapod machine tool is a machining center built on a Gough–Stewart platform, where six variable-length struts move the spindle with six degrees of freedom, introduced in the 1990s.

Hexcel

Hexcel Corporation is an American manufacturer of advanced composite materials, including carbon fiber, prepregs, resins, adhesives, and honeycomb core, founded in 1948 and headquartered in Stamford, Connecticut.

HexClad Cookware

HexClad Cookware is an American cookware brand founded in 2016 by Daniel Winer and Cole Mecray, known for hybrid pans combining laser-etched stainless steel hexagons with nonstick coating.

Hexion

Hexion Inc. is an American specialty chemicals company headquartered in Columbus, Ohio, formed in 2005 by Apollo from Borden Chemical, Bakelite AG, and two Resolution companies.

Heydar Aliyev Center

The Heydar Aliyev Center is a cultural center in Baku, Azerbaijan, housed in a free-form building with no straight lines, designed by Zaha Hadid Architects and opened in 2012.

Heydar Aliyev International Airport

Heydar Aliyev International Airport, formerly Baku Airport, is Azerbaijan's largest airport, serving Baku from 20 km east of the city and hub of Azerbaijan Airlines.