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The iMac G3, originally released as the iMac, is a series of personal computers sold by Apple Computer from 1998 to 2003. Following Steve Jobs 's return to the financially troubled company that he co-founded, he aggressively restructured its offerings. The iMac was envisioned as Apple's new inexpensive and consumer-friendly desktop product ...
In probability theory and statistics, the Poisson distribution is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time if these events occur with a known constant mean rate and independently of the time since the last event. [1] .
In mathematics, the Fibonacci sequence is a sequence in which each number is the sum of the two preceding ones. Numbers that are part of the Fibonacci sequence are known as Fibonacci numbers, commonly denoted Fn . The sequence commonly starts from 0 and 1, although some authors start the sequence from 1 and 1 or sometimes (as did Fibonacci ...
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Plasma was first identified in laboratory by Sir William Crookes. Crookes presented a lecture on what he called "radiant matter" to the British Association for the Advancement of Science, in Sheffield, on Friday, 22 August 1879.However, systematical studies of plasma began with the research of Irving Langmuirand his colleagues in 1920's. Langmuir a...
The fourth state of matter
Plasma is called the fourth state of matter after solid, liquid, and gas.It is a state of matter in which an ionized substance becomes highly electrically conductive to the point that long-range electric and magnetic fieldsdominate its behaviour. Plasma is typically an electrically quasineutral medium of unbound positive and negative particles (i.e. the overall charge of a plasma is roughly zero). Although these particles are unbound, they are not "free" in the sense of not experiencing force...
Ideal plasma
Three factors define an ideal plasma: 1. The plasma approximation: The plasma approximation applies when the plasma parameter Λ, representing the number of charge carriers within the Debye sphere is much higher than unity.It can be readily shown that this criterion is equivalent to smallness of the ratio of the plasma electrostatic and thermal energy densities. Such plasmas are called weakly coupled. 2. Bulk interactions: The Debye lengthis much smaller than the physical size of the plasma. T...
Non-neutral plasma
The strength and range of the electric force and the good conductivity of plasmas usually ensure that the densities of positive and negative charges in any sizeable region are equal ("quasineutrality"). A plasma with a significant excess of charge density, or, in the extreme case, is composed of a single species, is called a non-neutral plasma. In such a plasma, electric fields play a dominant role. Examples are charged particle beams, an electron cloud in a Penning trapand positron plasmas.
Density and ionization degree
For plasma to exist, ionization is necessary. The term "plasma density" by itself usually refers to the electron density n e {\displaystyle n_{e}} , that is, the number of free electrons per unit volume. The degree of ionization α {\displaystyle \alpha } is defined as fraction of neutral particles that are ionized: 1. α = n i n i + n n {\displaystyle \alpha ={\frac {n_{i}}{n_{i}+n_{n}}}} , where n i {\displaystyle n_{i}} is the ion density and n n {\displaystyle n_{n}} the neutral density (in...
Temperature
Plasma temperature, commonly measured in kelvin or electronvolts, is a measure of the thermal kinetic energy per particle. High temperatures are usually needed to sustain ionization, which is a defining feature of a plasma. The degree of plasma ionization is determined by the electron temperature relative to the ionization energy (and more weakly by the density). In thermal equilibrium, the relationship is given by the Saha equation. At low temperatures, ions and electrons tend to recombine i...
Plasma potential
Since plasmas are very good electrical conductors, electric potentials play an important role.[clarification needed] The average potential in the space between charged particles, independent of how it can be measured, is called the "plasma potential", or the "space potential". If an electrode is inserted into a plasma, its potential will generally lie considerably below the plasma potential due to what is termed a Debye sheath. The good electrical conductivity of plasmas makes their electric...
To completely describe the state of a plasma, all of theparticle locations and velocities that describe the electromagnetic field in the plasma region would need to be written down.However, it is generally not practical or necessary to keep track of all the particles in a plasma.[citation needed]Therefore, plasma physicists commonly use less detail...
Plasmas are the object of study of the academic field of plasma science or plasma physics, including sub-disciplines such as space plasma physics. It currently involves the following fields of active research and features across many journals, whose interest includes: Plasmas can appear in nature in various forms and locations, which can be usefull...
Although the underlying equations governing plasmas are relatively simple, plasma behaviour is extraordinarily varied and subtle: the emergence of unexpected behaviour from a simple model is a typical feature of a complex system. Such systems lie in some sense on the boundary between ordered and disordered behaviour and cannot typically be describe...
Hall effect thruster. The electric field in a plasma double layer is so effective at accelerating ions that electric fields are used in ion drives.Plasma sprayingTokamak plasma in nuclear fusion researchIntroduction to Plasma Physics: Graduate course given by Richard Fitzpatrick|M.I.T. Introduction by I.H.HutchinsonHow to make a glowing ball of plasma in your microwave with a grape|More (Video)0 (zero) is a number representing an empty quantity. Adding 0 to any number leaves that number unchanged. In mathematical terminology, 0 is the additive identity of the integers, rational numbers, real numbers, and complex numbers, as well as other algebraic structures. Multiplying any number by 0 has the result 0, and consequently, division ...
Archimedes of Syracuse[ a] ( / ˌɑːrkɪˈmiːdiːz / AR-kim-EE-deez; [ 2] c. 287 – c. 212 BC) was an Ancient Greek mathematician, physicist, engineer, astronomer, and inventor from the ancient city of Syracuse in Sicily. [ 3] Although few details of his life are known, he is regarded as one of the leading scientists in classical antiquity.
The domestic cat has a smaller skull and shorter bones than the European wildcat. [ 49] It averages about 46 cm (18 in) in head-to-body length and 23–25 cm (9.1–9.8 in) in height, with about 30 cm (12 in) long tails. Males are larger than females. [ 50] Adult domestic cats typically weigh 4–5 kg (8.8–11.0 lb).
