The Hall effect is a type of electromagnetic effect, a phenomenon discovered by the American physicist E.H. Hall (1855-1938) in 1879 while studying the conductive mechanism of metals.
When the current perpendicular to the external magnetic field through the semiconductor, the carriers are deflected, perpendicular to the direction of the current and the magnetic field will produce an additional electric field, which in the semiconductor at the two ends of the potential difference, this phenomenon is the Hall effect, this potential difference is also known as Hall potential difference. The Hall effect is judged using the left-hand rule.
Expanded:
1. Hall effect applications:
The Hall effect is particularly important in applied technology. According to the Hall effect made of Hall devices, is a magnetic field as the working media, the object's motion parameter into a digital voltage form of output, so that it has the function of sensing and switching.
2. Integer quantum Hall effect:
The square ratio h of quantized conductance e was observed, providing experimental support for the important concept of ballistic transport.
3. Fractional quantum Hall effect:
Laughlin and J. K. Jean explained its origin. The pair's work revealed the importance of vortexes and quasi-particles in condensed matter physics.
Applications of the bioelectromagnetic effect:
Using the bioelectromagnetic effect, it is possible to investigate new methods of diagnosing diseases. For example, various human body magnetograms (cardiac magnetogram, brain magnetogram, lung magnetogram, etc.) can provide information about the physiological and pathological states of the human body, and can be used as an effective means of diagnosing diseases by comparing abnormal and normal magnetograms.
The use of bioelectromagnetic effect can also enrich new treatment methods. For example, the evoked potential instrument developed by the Institute of Electrical Engineering, microwave therapeutic instrument and a variety of magnetic therapy devices. This part of the research content can strongly promote the development of new medical equipment and development work.
With the increasing attention of governments to life and health and environmental protection, the research fields of life science, biotechnology and environmental science have been vigorously developed. At the same time, the research on bioelectromagnetic effects is also getting more and more attention. It is urgent to focus on the overall advantages of the Chinese Academy of Sciences to carry out research on bioelectromagnetic effects.
The Institute of Electrical Engineering (IEE) of the Chinese Academy of Sciences (CAS) has carried out a lot of work on the basic research of bioelectromagnetic effects, and has developed a variety of medical equipment utilizing bioelectromagnetic effect principles. At the same time, the Institute of Electrical Engineering also has a variety of advanced electromagnetic field detection devices and a variety of magnets.
At present, there are nearly ten sets of permanent magnets with field values from 40mT to 1800mT and different sizes; there are many sets of normal-conducting magnets; in particular, there are many sets of superconducting magnets in the Open Laboratory of Superconducting Electrotechnology with a maximum magnetic field of up to 14 T. All of these have laid a good foundation for the further development of the research on bioelectromagnetic effects.
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