Wednesday, 4 March 2015

Nuclear Physics


Nuclear physics is operated both theoretically and experimentally. Its key theoretical tool is quantum mechanics. Experimental tools are for. As particle detectors and radiation detectors, particle accelerators and vacuum technology.

The object of the "pure" nuclear physics in the sense of basic research is the elucidation and explanation of the core structure, so the details of the structure of atomic nuclei.

From the study of radioactivity and of reactions with nuclei, many applications have developed, for example,

Energy from nuclear reactions by nuclear reactors and nuclear fusion reactors,
medical diagnostic and therapeutic procedures (such as scintigraphy, brachytherapy), combined nuclear medicine called

Chemical applications in radiochemistry and nuclear chemistry,

Procedures for preventive damage detection in pipelines by gamma radiation,

Production of material surfaces with special properties by ion implantation,

Helper methods for other research areas such as radiocarbon dating in archeology or Kosmochemie.

Typical orders of magnitude in the field of atomic nuclei and nuclear processes

Lengths: 1 Fermi = 1 fm = 10-15 m

Energy: 100 keV to 100 MeV

The constituents of the nucleus, the nucleons: protons and neutrons. The number of protons in a core is equal to the number of electrons in the neutral atom. Z determines the chemical properties of atoms and is therefore called the atomic number (or with respect to the nucleus and atomic number). The mass of the nucleus is determined by the number of all A nucleons and is therefore also called the mass number. As you can see, the neutron number N = A - Z. atoms having the same atomic number but different mass number isotopes are called. The physical properties of the core depends both on the atomic number and the number of neutrons from the chemical properties (almost) only on the atomic number.

In the description of nuclear reactions and scattering processes, the concept of the cross section of importance. The cross section for a given process is a measure of the probability that this process occurs in each case.

Application Of Mutual Induction


Principle of inductive coupling, with the Description field (A) and as a network model (B)
In the scope of the electromagnetic compatibility (EMC) is the mutual inductance referred to as magnetic coupling or inductive coupling, and describes the undesirable as a rule, magnetic coupling of adjacent electrical circuits. Caused by the current in a circuit magnetic flux, like the adjacent circuit diagram example of the circuit consisting of the AC voltage source U1, caused by magnetic coupling in the second circuit, shown with the AC voltage source U2, an additional induced source voltage, which in this circuit as an undesirable disturbance may occur.

The modeling can be implemented as appropriate as a field model (A) with the variable magnetic field, or equivalent to take place in the field of network theory by means of the mutual inductance M's, as shown in the right figure in case (B). The induced voltage against Ug_ {2} in the second conductor loop, which is due to the current i_ 1 from the first conductor loop is:

Ug_ {2} = M_ {s} \ cdot \ frac {\ mathrm {d} i_ 1} {\ mathrm {d} t}
Due to the symmetry of a mutual inductance Ms is a reciprocal four-terminal network.

Due to the higher energy density of the magnetic field as compared to the electric field, a relatively high power transmission may be achieved at intermediate frequencies by means of inductive coupling. This fact is exploited in transformers or electrical drive systems such as the gap motor.

In the field of communications, the inductive coupling is utilized as part of the inductive transmission, for example in the contactless signal transmission between the sensor signal of a sensor and display device or contactless chip cards, so-called RFID.