A goal or objective is an idea of the future or desired result that a person or a group of people envision, plan and commit to achieve. People endeavour to reach goals within a finite time by setting deadlines. A goal is roughly similar to a purpose or aim, the anticipated result which guides reaction, or an end, which is an object, either a physical object or an abstract object, that has intrinsic value. Goal setting Goal-setting theory was formulated based on empirical research and has been called one of the most important theories in organizational psychology.
The theory of solar cells explains the process by which light energy in photons is converted into electric current when the photons strike a suitable semiconductor device. The theoretical studies are of practical use because they predict the fundamental limits of a solar cell, and give guidance on the phenomena that contribute to losses and solar cell efficiency. Photons in sunlight hit the solar panel and are absorbed by semi-conducting materials. Electrons (negatively charged) are knocked loose from their atoms as they are excited.
In electrochemistry, a half-cell is a structure that contains a conductive electrode and a surrounding conductive electrolyte separated by a naturally occurring Helmholtz double layer. Chemical reactions within this layer momentarily pump electric charges between the electrode and the electrolyte, resulting in a potential difference between the electrode and the electrolyte. The typical anode reaction involves a metal atom in the electrode being dissolved and transported as a positive ion across the double layer, causing the electrolyte to acquire a net positive charge while the electrode acquires a net negative charge.
Le canon électro-magnétique, connu aussi sous le nom anglais de railgun — ou rail gun — d'où la traduction canon à rails – à ne pas confondre avec l'artillerie lourde sur voie ferrée (1914-1918 et 1939-1945) – est une arme à projectile accéléré par une force électromagnétique, semblable à celle qui fait tourner le moteur homopolaire. Le concept sous-jacent est probablement aussi ancien que la découverte de la force de Laplace (avec une proposition en France dès 1884, puis 1908, et une tentative de développement pendant la Première Guerre mondiale qui fut abandonnée faute de résultat probant).
