Добавил:
Upload Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
All_answers.docx
Скачиваний:
0
Добавлен:
01.07.2025
Размер:
79.67 Кб
Скачать

9. The general scheme of transfer and registration of the information. Electrodes.

To receive and fix the information on a condition and parameters of medical and biologic system, it is necessary to have the whole set of devices. The primary element of this set a-sensitive element of means of measurements is called as the device of removal. The signal which is given out by the device of removal,registered by the special device.These methods are widely applied in engineering, in biology, in medicine. ELECTRODES: Electrode - is the conductors of the special form connecting a measuring circuit with biological system. Electrodes should have properties: fixed and removed quickly, have high stability of electric parameters, to be strong, to not create handicapes, to not irritate a biological tissue.

10. Sensors. Kinds of sensors.

Many medical and biologic characteristics cannot be removed by electrodes as they are not reflected by a bioelectric signal,in these cases sensors are used. The device, changing the measured or controllable not electric size in an electric signal is called sensor. Sensors are divided on generating and parametrical. Generatingare sensors, which under influence of a measured signal directly generates a voltage or a current. To such sensors concern:

Piezoelectric, based on piezoelectric effect;

Thermoelectric, based on thermal electricity;

Induction, based on action of an electromagnetic induction;

Photo-electric, based on photo-electric effect.

Sensors in which under influence of mechanical efforts or movings electric parameters change, are called parametrical. Types of these sensors refer to the same as also the phenomena on which they are based:

Resistance - resistive sensors;

Capacity - capacitor sensors;

Inductance - inductive sensors

11. Application of sensors.

Application of microelectronic devices in medicine allows not only to reduce the sizes of devices and devices, but also to create devices and sensors in very small sizes.Tiny electric manometer is applied, for measurement of pressure in cavities of heart.The new method endoradiometry is developed for research of a gastroenteric path. Research of temperature, pressure and acidity of environment is made during all paths by means of endoradioprobe, having the form of a pill which the investigated patient swallows.Semi-conductor sensor serves as the sensor of temperature in endoradioprobe, the sensor of pressure - the coil of inductance of an oscillatory contour of the generator connected with a membrane.

12. X-rays, its nature, its place in scale of electromagnetic waves.

Professor Wilhelm Konrad Roentgen experimented Krucs tubes in 1895.Rontgen has firmly established that: X-rays differ from cathode rays, do not bear a charge, do not deviate a magnetic field, are raised by cathode rays. They are invisible to an eye, possess high penetrating ability, act on a magnetic field. Thus, the short electromagnetic impulse arises and extends. X-rays are an electromagnetic wave with wavelength from 80 nanometers up to 0, 0001 nanometers, in a scale of electromagnetic waves X-rays borders with ultra-violet and γ-rays.Sources of x-ray radiation it is possible to divide on two groups: natural and artificial. Natural sources of radiation.Some radioactive isotopes can serve as sources of X-rays. The sun is source of X-ray radiation also. Its X-ray radiation is so huge, that is capable to destroy in a few minutes all alive on the Earth. Artificial sources of radiation(are X-ray tubes).

13. X-ray tube.

Artificial sources of radiation isx-ray tube. X-ray tube represents glass flask with high vacuum, with the cathode and the anode, at oblique which end face there is a plate - a pocket mirror from heavy metal. The heated spiral cathode (1) is a source of electrons. The stream of electrons (4) is accelerated in the strong electric field created between the cathode and the anode (2). The accelerated stream of electrons is broken by substance of the anode and causes occurrence X – rays (3). This is brake radiation. The part of electrons gets into substance of the anode and causes characteristic radiation. A feed of a x-ray tube is provided with two sources: a source of a high pressure for an anode circuit and a source of a low pressure.

Соседние файлы в предмете [НЕСОРТИРОВАННОЕ]