one-step diffusion
121Marcus theory — is a theory originally developed by Rudolph A. Marcus, starting in 1956, to explain the rates of electron transfer reactions – the rate at which an electron can move or jump from one chemical species (called the electron donor) to another (called …
122reaction mechanism — Introduction in chemical reactions (chemical reaction), the detailed processes by which chemical substances are transformed into other substances. The reactions themselves may involve the interactions of atoms (atom), molecules (molecule),… …
123respiration, human — ▪ physiology Introduction the process by which oxygen is taken up and carbon dioxide discharged. The design of the respiratory system The human gas exchanging organ, the lung, is located in the thorax, where its delicate tissues are… …
124Hill cipher — Hill s cipher machine, from figure 4 of the patent In classical cryptography, the Hill cipher is a polygraphic substitution cipher based on linear algebra. Invented by Lester S. Hill in 1929, it was the first polygraphic cipher in which it was… …
125Egypt, ancient — Introduction civilization in northeastern Africa dating from the 3rd millennium BC. Its many achievements, preserved in its art and monuments, hold a fascination that continues to grow as archaeological finds expose its secrets. This article… …
126Mixture model — See also: Mixture distribution In statistics, a mixture model is a probabilistic model for representing the presence of sub populations within an overall population, without requiring that an observed data set should identify the sub population… …
127photography, technology of — Introduction equipment, techniques, and processes used in the production of photographs. The most widely used photographic process is the black and white negative–positive system (Figure 1 >). In the camera the lens projects an image of… …
128pre-Columbian civilizations — Introduction the aboriginal American Indian (Mesoamerican Indian) cultures that evolved in Meso America (part of Mexico and Central America) and the Andean region (western South America) prior to Spanish exploration and conquest in the 16th …
