![<?echo $_SERVER['SERVER_NAME'];?>](/template/twentyseventeen/skin/images/header.jpg)
GTCD-1 magnetic buoyancy measuring instrument manual
I. Overview
The complete diamagnetic and zero resistance effects are one of the main features of superconducting materials. When a superconductor is in an external magnetic field, the shielding current is induced inside the superconductor due to the anti-magnetic and magnetic pinning effects, and the shielding current hardly decays with time due to the zero resistance effect. The magnetic field generated by the shield current that continuously flows in the superconductor interacts with the external magnetic field to generate superconducting magnetic levitation. The superconducting magnetic levitation technology based on superconducting magnetic levitation has potential application value in energy (flywheel energy storage), transportation (magnetic locomotive), machinery industry (frictionless bearing) and many other fields.
The superconductor suspension force measuring device is composed of a superconductor, a cryogenic container, a moving mechanism, a load cell, a displacement sensor, a data display device, and a control system. The device measures the interaction between the superconducting material and the permanent magnet and plots the magnetic buoyancy and distance through a recorder, plotter or computer.
The function of the superconductor levitation force measuring device is to measure the magnetic buoyancy characteristics of the superconducting block and draw a corresponding curve to show the relationship between the force and the relative distance between the superconducting block and the permanent magnet. When the distance between the two changes from large to small, the force is expressed as repulsive force (F>0), and the repulsive force increases with the decrease of the relative distance; when the distance becomes smaller, the attraction is generated (F<0), attracting The force has a maximum value at a certain position. The device is particularly suitable for use in university modern physics teaching experiments.
Magnetic buoyancy is an important parameter for the application of superconducting materials in magnetic levitation technology. The variation of the magnetic buoyancy with the levitation gap depends on the one hand on the nature of the superconducting material itself and on the other hand on the strength and distribution of the magnetic field and the measurement conditions such as temperature.
The device can be used for the measurement of magnetic buoyancy characteristics and the development of magnetic buoyancy measurement standards for superconducting materials in research and application research of superconducting bulk materials.
Second, the main technical indicators
Force measurement range
0 ~ 50 Kg
Pull pressure sensor accuracy
0.05%
Resistance displacement sensor linearity
0.1%
Force measurement accuracy
0.2 N
Displacement measurement accuracy
0.1 mm
Sample
Bulk REBaCuO superconducting material with a diameter of 50 mm or less and a critical transition temperature higher than 77 K
Magnet
NdFeB permanent magnet, the diameter to height ratio is about 1, and the magnetic field is about 5000 Gs (measured on the iron block)
test temperature
77.3 K (liquid nitrogen temperature)
Magnet movement range
0 ~ 100 mm
Test frame dimensions
320 mm x260 mmx700 mm
Test stand net weight
27 Kg
Control display unit power
220 V, 50 Hz
Control display unit size
300 mm x250 mmx140 mm
Control display unit net weight
1 Kg
Third, the structure and operation instructions
As shown in Fig. 1, the measuring instrument comprises a frame for supporting and fixing various functional components, a cryogenic container for placing the superconducting sample to be tested, a measuring magnet, a vertical moving mechanism, a measuring component for force and displacement, and a control and Display source. The magnet is coupled to the lower end surface of the vertical moving mechanism.
Figure 1 Manual superconductor magnetic buoyancy measuring instrument
Source Control Display Unit Button Definition:
K1 — Set value increase button K2 — Online and maximum pressure setting button K3 — Pressure clear and displacement upper limit setting button
K4 — Pause and set value confirmation button K5 — Set value decrease button K6 — Offline
K7 — Displacement clear and displacement lower limit setting button K8 — Set button The upper right button of the panel is the reset button.
Use and operating instructions
1. Check that the various mechanisms and components are in a normal state and turn on the power of the load cell.
2. Place the superconducting block to be measured into the liquid nitrogen box and fix it.
3. Record the initial value displayed by the sensor meter and the initial distance displayed by the scale.
4. Start pouring liquid nitrogen into the liquid nitrogen box. After the liquid nitrogen boiling tends to be gentle, wait for 3-5 minutes to ensure that the superconducting block is completely cooled and enters the superconducting state. Be careful not to spill liquid nitrogen on your hands.
Or on the skin.
5. Turn the drive handle to move the permanent magnet at the lower end of the telescopic rod downward. The amount of movement should be consistent each time, and the moving pitch should be determined according to the accuracy requirements of the measurement. Moving interval
The smaller the curve, the smoother the curve drawn.
6. Record the force value and corresponding distance value displayed by the sensor meter after each movement.
7. Turn the drive handle to move the telescopic rod down until the permanent magnet just touches the superconducting block (0 distance). At this time, the data displayed by the load cell minus the initial value is super
The maximum levitation force of the guide block.
8. Move the telescopic rods upwards at equal intervals and record the value after each movement.
9. After the test is finished, mark all the points corresponding to (distance, levitation force) on the coordinate paper, and connect the points smoothly to obtain the curve of the magnetic buoyancy and distance of the superconducting block.
a, pressure zero setting:
Press K3 to display the pressure display to zero.
b, displacement zero setting:
Method 1: Turn on the power switch, and shake the handle clockwise to move the magnet down to the vicinity of the sample (such as contact with the sample, the pressure gauge has a numerical value), until the pressure is displayed in 10~20 Newtons.
Between, then press the K7 key to clear the displacement.
Method 2: Turn on the power switch, clear the pressure, record the displacement display value (for example, 150mm), and measure the actual distance between the sample and the magnet with a measuring tool (caliper, etc.)
Off (for example, 50mm), subtract the actual value from the displayed value (in this case, 100mm), press the K8, K7, and K6 keys in sequence to enter the zero setting, press the K1 key to zero.
Move up to the difference (100mm) of the displayed value over the actual value and press the K4 key to confirm the set value.
Fourth, the pressure-displacement curve test method
1) Zero field cooling experiment steps
1. Turn on the tester's power switch and warm up for 5 minutes.
2. Fix the sample to the center of the sample holder with screws;
3. Press K3 to reset the pressure value to zero.
4. Shake the handle clockwise to lower the magnet to the vicinity of the sample, adjust the position of the magnet to center the sample, and the pressure is displayed between 10 and 20 Newtons, then press the K7 button to shift
Cleared.
5. Shake the handle counterclockwise to raise the magnet up to 35mm or more;
6. Inject liquid nitrogen into the cryocontainer to cool the sample to the liquid nitrogen temperature without the action of an external magnetic field. Keep the liquid nitrogen surface slightly above the upper surface of the sample (due to the liquid during the test)
When the nitrogen evaporation level drops, you can add liquid nitrogen at any time. Press K3 again to check the pressure.
7. Execute c:\cdjcc\cdjc.exe to run the test software. The following interface appears (Figure 2)
(figure 2)
8. Select the parameter settings and enter the following interface (Figure 3). Press the K2 button on the tester panel to connect, and you can see the pressure and displacement values ​​on the computer screen.
(image 3)
9. Fill in the sample number, size, cooling method and magnet size and surface magnetic field, whether the data is saved, sampling period (≥100ms), etc.
10. Click on the pressure-displacement test chart on the toolbar. Go to the following screen (Figure 4).
(Figure 4)
11. Fill in the maximum pressure, minimum pressure and displacement range and ordinate position to determine the coordinate axis.
12. Click on the “Start Drawing†box to select the drawing curve. The data is recorded in the database, then shake the handle clockwise to make the magnet descend to the superconducting sample, and shake it counterclockwise after contact.
The handle moves the magnet up to 35mm and clicks “Stop Drawingâ€. If necessary, you can save the test chart by clicking "Save" in the lower right corner. If using a recorder or plotter
Draw a test curve and connect the meter to the recorder before testing. The signal output connector on the rear panel of the tester is used to connect a recorder or a plotter, where 1 (green line,
Displacement negative), 2 (red line, positive displacement), 3 (blue line, negative pressure), 4 (yellow line, positive pressure). The rear panel knob is potential compensation, which can adjust the output voltage to record.
Within the range of the instrument.
13. Click “Database†in the toolbar to save the database and save the test database. The default database storage format is "EXCEL" format.
14. When repeating the measurement, you must wait for the liquid nitrogen to completely evaporate (or loosen the sample to remove the sample from the sample holder), so that the whole sample is heated to above 90 K (converted to normal state) to make it frozen.
The magnetic field in the sample is withdrawn. Note that rapid water temperature or hot air blowing will cause cracks in the sample, resulting in a significant decrease in performance.
15. Turn off the power to the tester after the experiment is finished, remove the sample, dry it, and store it in a dry dish.
2) Field cooling experiment steps
1. Turn on the tester's power switch and warm up for 5 minutes.
2. Fix the sample to the center of the sample holder with screws;
3. Press K3 to reset the pressure value to zero.
4. Shake the handle clockwise to lower the magnet to the vicinity of the sample, adjust the position of the magnet to center the sample, and the pressure is displayed between 10 and 20 Newtons, then press K7 to clear the displacement.
5. Shake the handle counterclockwise to move the magnet up to any position between 1 and 10 mm.
6. Inject liquid nitrogen into the cryocontainer to cool the sample to the liquid nitrogen temperature under the action of an external magnetic field (to avoid immersing the magnet in liquid nitrogen), press K3 again to check the pressure.
7. Execute c:\cdjcc\cdjc.exe to run the test software. Appears (Figure 2) interface
8. Select the parameter settings and enter the interface (Figure 3). Press the K2 button on the tester panel to connect, and you can see the pressure and displacement values ​​on the computer screen.
9. Fill in the sample number, size, cooling method and magnet size and surface magnetic field, whether the data is saved, sampling period (≥100ms), etc.
10. Click on the pressure-displacement test chart on the toolbar. Enter the (Figure 4) interface.
11. Fill in the maximum pressure, minimum pressure and displacement range and ordinate position to determine the coordinate axis.
12. Click the “Start Drawing†box to select the drawing curve. Shake the handle clockwise to move the magnet down or counterclockwise to move the magnet up (only the attraction is measured), and the data is recorded in the number.
According to the library. When the test process is complete, click "Stop Drawing". If necessary, you can save the test chart by clicking "Save" in the lower right corner. If using a recorder or plotter
To test the curve, connect the meter to the recorder before testing. The signal output interface on the rear panel of the tester is used to connect a recorder or a plotter, where 1 is a green line, displacement
Negative; 2 is the red line, the displacement is positive; 3 is the blue line, the pressure is negative; 4 is the yellow line, the pressure is positive. The rear panel knob is potential compensation, which can adjust the output voltage to the recorder range.
Within the scope.
13. Click “Database†in the toolbar to save the database and save the test database. The default database storage format is "EXCEL" format.
14. When repeating the measurement, you must wait for the liquid nitrogen to completely evaporate (or loosen the sample to remove the sample from the sample holder), so that the whole sample is heated to above 90 K (converted to normal state) to make it frozen.
The magnetic field in the sample is withdrawn. Note that rapid water temperature or hot air blowing will cause cracks in the sample, resulting in a significant decrease in performance.
15. Turn off the power to the tester after the experiment is finished, remove the sample, dry it, and store it in a dry dish.
Five, pressure-time curve test method
1) Zero field cooling experiment steps
1. Turn on the tester's power switch and warm up for 5 minutes.
2. Fix the sample to the center of the sample holder with screws;
3. Press K3 to reset the pressure value to zero.
4. Shake the handle clockwise to lower the magnet to the vicinity of the sample, adjust the position of the magnet to center the sample, and the pressure is displayed between 10 and 20 Newtons, then press K7 to clear the displacement.
5. Rotate the handle counterclockwise to move the magnet up to the set position;
6. Inject liquid nitrogen into the cryocontainer to cool the sample to the liquid nitrogen temperature without the action of an external magnetic field. Keep the liquid nitrogen surface slightly above the upper surface of the sample (due to the liquid during the test)
When the nitrogen evaporation level drops, you can add liquid nitrogen at any time. Press K3 again to check the pressure.
7. Execute c:\cdjcc\cdjc.exe to run the test software. Appears (Figure 2) interface
8. Select the parameter settings and enter the (Figure 3) interface. Press the K2 button on the tester panel to connect, and you can see the pressure and displacement values ​​on the computer screen.
9. Fill in the sample number, size, cooling method and magnet size and surface magnetic field, whether the data is saved, sampling period (≥100ms), etc.
10. Click on the pressure-time test chart on the toolbar. Enter the (Figure 4) interface.
11. Fill in the maximum pressure, minimum pressure and displacement range and ordinate position to determine the coordinate axis.
12. Shake the handle clockwise to stop the magnet down to the set point, then click on the “Start†box to select the drawing curve and the data is recorded in the database. When the test process is complete, click "Stop". If necessary, you can save the test chart by clicking "Save" in the lower right corner. If the test curve is drawn with a recorder or plotter, connect the meter to the recorder before testing. The signal output interface on the rear panel of the tester is used to connect to the recorder or plotter, where 1 (green line, negative displacement), 2 (red line, positive displacement), 3 (blue line, negative pressure), 4 (yellow line, The pressure is positive). The rear panel knob is potential compensated and the output voltage can be adjusted within the recorder's range. The 1, 2 lines are not connected, and the time of the recorder is directly used as the X axis.
13. Click “Database†in the toolbar to save the database and save the test database. The default database storage format is "EXCEL" format.
14. When repeating the measurement, you must wait for the liquid nitrogen to completely evaporate (or loosen the sample to remove the sample from the sample holder), so that the whole sample is heated to above 90 K (converted to the normal state), so that the magnetic field frozen in the sample is retracted. Note that rapid water temperature or hot air blowing will cause cracks in the sample, resulting in a significant decrease in performance.
After the experiment is finished, turn off the power of the tester, and take out the sample and dry it in a dry dish.
2) Field cooling experiment steps
1. Turn on the tester's power switch and warm up for 5 minutes.
2. Fix the sample to the center of the sample holder with screws;
3. Press K3 to reset the pressure value to zero.
4. Shake the handle clockwise to lower the magnet to the vicinity of the sample, adjust the position of the magnet to center the sample, and the pressure is displayed between 10 and 20 Newtons, then press K7 to clear the displacement.
5. Shake the handle counterclockwise to move the magnet up to any position between 1 and 10 mm.
6. Inject liquid nitrogen into the cryocontainer to cool the sample to the liquid nitrogen temperature under the action of an external magnetic field (to avoid immersing the magnet in liquid nitrogen), press K3 again to check the pressure.
7. Execute c:\cdjcc\cdjc.exe to run the test software. Appears (Figure 2) interface
8. Select the parameter settings and enter the (Figure 3) interface. Press the K2 button on the tester panel to connect, and you can see the pressure and displacement values ​​on the computer screen.
9. Fill in the sample number, size, cooling method and magnet size and surface magnetic field, whether the data is saved, sampling period (≥100ms), etc.
10. Click on the pressure-time test chart on the toolbar. Enter the (Figure 4) interface.
11. Fill in the maximum pressure, minimum pressure and displacement range and ordinate position to determine the coordinate axis.
12. Click on the “Start Drawing†box to select the drawing curve. Shake the handle clockwise to move the magnet down or counterclockwise to move the magnet up (only the attraction is measured) to the desired position. The data is recorded in the database. When the test process is complete, click "Stop Drawing". If necessary, you can save the test chart by clicking "Save" in the lower right corner. If the test curve is drawn with a recorder or plotter, connect the meter to the recorder before testing. The signal output interface on the rear panel of the tester is used to connect to the recorder or plotter, where 1 (green line, negative displacement), 2 (red line, positive displacement), 3 (blue line, negative pressure), 4 (yellow line, The pressure is positive). The rear panel knob is potential compensated and the output voltage can be adjusted within the recorder's range. The 1, 2 lines are not connected, and the time of the recorder is directly used as the X axis.
13. Click “Database†in the toolbar to save the database and save the test database. The default database storage format is "EXCEL" format.
14. When repeating the measurement, you must wait for the liquid nitrogen to completely evaporate (or loosen the sample to remove the sample from the sample holder), so that the whole sample is heated to above 90 K (converted to the normal state), so that the magnetic field frozen in the sample is retracted. Note that rapid water temperature or hot air blowing will cause cracks in the sample, resulting in a significant decrease in performance.
15. Turn off the power to the tester after the experiment is finished, remove the sample, dry it, and store it in a dry dish.
Sixth, the results
The data recorded during the measurement is drawn on the coordinate paper or input into the computer to obtain the superconductor suspension force curve, as shown in Figure 5:
Tip: To avoid aliasing on the curve, the reading pause interval should be as small as possible. You can try to rotate the crank continuously by one student, the second student quickly reads the distance and sensor values, and the third student records the second student's reading.
Seven, thinking questions
1. Why does the curve appear fluctuating or jagged when the reading pause time is large?
2. During the reverse upward movement, when the magnet exceeds a certain distance between the surface of the superconducting block, why does the force sensor display a negative value?
Figure 5 Schematic diagram of the superconductor levitation force variation curve
Mositurizing Hand Gloves Mask
SOLO GLOW HAIR COSMETICS , https://www.hairdyecolorfactory.com