stationäres

Stationäres is a German adjective form derived from stationär, meaning stationary, fixed, or unchanging over time. It is used before neuter singular nouns in certain grammatical contexts, most commonly after the indefinite article or when no article is used. For example: ein stationäres System or ein stationäres Gleichgewicht. In contrast, other genders use different endings, such as die stationäre Phase (feminine) or das stationäre System (neuter with a definite article in the nominative/accusative).

In scientific and technical usage, stationäres describes conditions that do not change as time progresses. In physics, chemistry, and engineering, the term often appears in the sense of a stationary or steady state. A stationary state is a condition where macroscopic properties remain constant over time, even if the system exchanges energy or matter with its surroundings. In dynamical systems and differential equations, a stationäre (stationary) solution is one in which derivatives with respect to time vanish, yielding a time-invariant state. In probability theory, a stationärer (stationary) process has statistical properties that are invariant under time shifts.

The concept also appears in applied fields such as chromatography, where the stationary phase (die stationäre Phase) interacts with a mobile phase to separate components, and in biology or ecology when describing populations that maintain constant average properties in a changing environment. While closely related to the idea of equilibrium, a stationary state is not necessarily in thermodynamic equilibrium; it can be maintained by continuous input and output of energy or matter.

Overall, stationäres indicates a neuter-singular, time-invariant quality used across disciplines to denote steadiness or constancy in a system’s behavior.