CN102081067B - Carbon nano tube film ionization type nitrogen dioxide sensor and concentration measuring method thereof - Google Patents

Abstract

The invention discloses a carbon nanotube film ionization type nitrogen dioxide sensor and a concentration measurement method thereof, wherein the sensor comprises a first electrode, a second electrode and a third electrode which are sequentially distributed, the first electrode is provided with air holes, and the inner surface of the first electrode is attached with a metal film substrate distributed with a carbon nanotube film; the center of the second electrode is provided with a lead-out hole; a blind hole is formed in the surface of the third electrode; the three electrodes are isolated from each other. The method comprises the following steps: 1) placing three sensors with different inter-polar distances; 2) applying a voltage across the electrodes; 3) measuring ion flow values of the sensors; 4) the measured value and the calibration values of the concentration, the temperature and the humidity of the nitrogen dioxide gas form a sample, and the sample and an interpolation sample construct a gas concentration measurement database; 5) constructing a data fusion instrument and establishing an accurate measurement model of the concentration of the nitrogen dioxide gas; 6) and inputting the actual measurement value of the sensor into the measurement model to obtain the accurate measurement value of the concentration of the nitrogen dioxide gas. The sensor has the advantages of high gas detection sensitivity, good linearity and high accuracy.

Description

Carbon nanotube film ionized nitrogen dioxide sensor and its concentration measurement method

technical field

The invention relates to the field of gas sensing, in particular to an ionized nitrogen dioxide sensor based on carbon nanotube film and gas discharge principle and a method for measuring the concentration of nitrogen dioxide.

Background technique

With the urgent need of gas measurement in all walks of life and the development of nanotechnology, nanosensors have made great progress. Especially with the discovery of carbon nanotubes at the end of the 20th century, carbon nanotubes have shown attractive application prospects in the fields of gas, temperature and humidity measurement. The carbon nanotube thin film two-electrode ionization sensor in the carbon nanotube gas sensor, temperature sensor and humidity sensor has become a research field in the field of gas, temperature and humidity measurement due to its advantages of high measurement sensitivity, wide gas measurement range and fast response. hotspot. The carbon nanotube film two-electrode ionization gas sensor is based on the principle of gas discharge, which overcomes the shortcomings of other types of carbon nanotube gas sensors that are saturated and poisoned in the measured gas, and has a wider gas concentration measurement range and a wider range of gas types to be measured. Gas-sensitive, temperature-sensitive, and humidity-sensitive sensors made of carbon nanotubes as sensitive materials have irreplaceable advantages of conventional sensors: First, carbon nanotubes have a large specific surface area, which can greatly improve the overall size of the sensor when the overall size of the sensor is small. The area of the electrode; the second is based on the nanoscale tip curvature radius of the carbon nanotubes, which greatly reduces the operating voltage of the sensor, and obtains a very strong electric field strength near the tip of the carbon nanotubes, ionizing the measured gas at a low voltage; The size of the sensor is greatly reduced, and the dynamic response is fast. Therefore, it has broad development prospects in biology, chemistry, machinery, aviation, military affairs, and anti-terrorism.

Existing carbon nanotube film two-electrode ionization sensors include carbon nanotubes disclosed by professors Liu Junhua, Zhang Yong, Li Xin, Zhu Changchun, etc. of Xi'an Jiaotong University at the 14th IVMC International Vacuum Microelectronics International Conference in 2001. Thin-film two-electrode ionization gas sensor (shown in Figure 1). After the sensor works, because the space charge is difficult to diffuse after the discharge between the electrodes, the sensor is difficult to return to the initial state, and the breakdown voltage, breakdown current and gas concentration of the sensor show a multi-valued relationship (Figure 2, Figure 3), and the gas concentration cannot be measured. Concentration is measured. Professor Nikhil Koratkar and Pulickel M Ajayan from Rensselaer Polytechnic Institute in the United States developed a carbon nanotube film anode two-electrode gas sensor. The breakdown voltage of the sensor shows a nonlinear relationship with the gas concentration, and the linear error between the breakdown discharge current and the gas concentration is large; the discharge voltage and discharge current are large; and the carbon nanotube thin film anode cannot measure a single gas. Professor Hui Guohua and Professor Chen Yuquan from the School of Biomedical Engineering and Instrument Science of Zhejiang University developed a carbon nanotube film cathode two-electrode gas sensor under the condition of 120 micron electrode spacing, and studied the discharge characteristics of the sensor in three single gases , due to low sensitivity, does not constitute a gas sensor for measuring concentration.

Therefore, the current research on the carbon nanotube film ionization sensor sensitive to various single gases including nitrogen dioxide and the method for measuring the concentration of nitrogen dioxide single gas has become a technical problem to be solved urgently.

Contents of the invention

One of the purposes of the present invention is to provide a carbon nanotube thin film ionized nitrogen dioxide sensor, which divides the output current of the traditional carbon nanotube thin film two-electrode sensor into electron flow and ion flow, and establishes the ionized nitrogen dioxide sensor of the present invention. The single-value correspondence between the ion flow collected by the collector of the sensor and the nitrogen dioxide gas concentration, temperature, and humidity overcomes the multi-value non-linear problem of the carbon nanotube film two-electrode sensor gas concentration sensitivity and humidity sensitivity. The sensor has the advantages of simple structure, low cost and high gas detection sensitivity.

Another object of the present invention is to provide a method for detecting the concentration of nitrogen dioxide gas based on a carbon nanotube thin film ionization nitrogen dioxide sensor. The sensor array is composed of carbon nanotube thin film ionization sensors with different electrode spacings, respectively measuring the concentration of nitrogen dioxide to be measured. Nitrogen dioxide gas concentration, gas temperature and humidity; the hardware structure required by the concentration measurement method is simple, the data fusion algorithm is adopted, and the gas detection accuracy is high.

The purpose of the present invention is achieved through the following technical solutions.

The carbon nanotube thin film ionized nitrogen dioxide sensor is characterized in that it includes three first electrodes, second electrodes and third electrodes distributed sequentially from top to bottom, and the first electrodes are attached with carbon electrodes distributed on the inner surface. The metal film base of the nanotube film and the electrode with air holes; the second electrode is composed of the lead-out electrode plate with the lead-out hole in the center; the third electrode is composed of the collector with the blind hole on the plate surface; the three The electrodes are respectively separated from each other by insulating struts.

Structural feature of the present invention is also in:

The electrode spacing between two adjacent electrodes among the three electrodes is 30-250 μm;

The facing area of the first electrode and the second electrode plate is 0.01-170 mm ² , and the facing area of the second electrode and the third electrode plate is 0.01-190 mm ² .

The electrode surface of the first electrode has 1 to 4 air holes, and a carbon nanotube film is grown or screen-printed on the metal film substrate attached to the inner surface of the electrode;

The center of the second electrode lead-out pole is provided with 1 to 4 lead-out holes;

The collector blind hole of the third electrode corresponds to the lead-out hole of the second electrode, and the number of blind holes is 1-4.

The present invention also provides a method for measuring the concentration of nitrogen dioxide gas based on a carbon nanotube thin film ionization nitrogen dioxide sensor, the method comprising the following steps:

(1) Select a carbon nanotube thin film ionization sensor with three electrodes whose electrode spacing between two adjacent electrodes is set to 30-250 μm;

(2) Place the carbon nanotube thin film ionization nitrogen dioxide sensor, carbon nanotube thin film ionization temperature sensor, and carbon nanotube thin film ionization humidity sensor with three different electrode spacings in the atmosphere containing the nitrogen dioxide to be measured. in a gaseous atmosphere;

(3) The first electrodes of the three carbon nanotube film ionized nitrogen dioxide sensors, the temperature sensor and the humidity sensor are loaded with a voltage of 0V, the second electrode is loaded with a voltage of 2-200V, and the third electrode is loaded with a voltage of 1-180V;

(4) within the measurement range of nitrogen dioxide gas concentration, temperature and humidity to be measured, corresponding to different concentration, temperature and humidity calibration values, respectively measure the gas discharge ion current values output by all sensors in step (2);

(5) All the sensor output ion current values measured in the concentration, temperature and humidity measurement ranges in step (4) are combined with the corresponding nitrogen dioxide gas concentration, temperature and humidity calibration values to form different samples, and the composition is different The experimental calibration samples, and then use the segmental interpolation technology to interpolate the experimental calibration samples to obtain the interpolation data, get the interpolation samples, and build the nitrogen dioxide gas concentration measurement database according to all samples including the experimental calibration samples and interpolation samples;

(6) Using data fusion technology, build a data fusion instrument, and establish measurement models for nitrogen dioxide sensors, temperature sensors and humidity sensors; use the data in the nitrogen dioxide gas concentration measurement database as the input samples and expected output samples of the data fusion instrument , and use different data within the range as the training samples and inspection samples of the data fusion instrument for training and inspection. When the inspection results meet the actual measurement error requirements, the data fusion instrument outputs an accurate measurement model for the concentration of the nitrogen dioxide sensor;

(7) The ion current value output during the actual measurement of carbon nanotube film ionized nitrogen dioxide sensor, temperature sensor and humidity sensor is input into the accurate measurement model of nitrogen dioxide gas concentration obtained in step (6), and the model outputs nitrogen dioxide gas Accurate measurement of concentration.

The inventive method is also characterized in that:

In the carbon nanotube film ionization nitrogen dioxide sensor, the potential of the second electrode is higher than the potential of the first electrode, and the potential of the third electrode is lower than the potential of the second electrode and higher than the potential of the first electrode.

The establishment of the nitrogen dioxide gas concentration measurement database is to form a database with experimental calibration data and interpolation data, and use the output ion current value of each sensor and its interpolation data as input samples, and use the nitrogen dioxide gas concentration, temperature and humidity calibration values and Its interpolated data serves as the desired output samples.

The nitrogen dioxide gas concentration measurement method based on the carbon nanotube thin film ionization nitrogen dioxide sensor, the sensor array is composed of carbon nanotube thin film ionization sensors with different electrode spacings to measure the concentration, temperature and humidity of the nitrogen dioxide gas to be measured respectively; Voltage source power supply; sensor output is detected by pA level current measurement system; electrode spacing is adjusted, electrode voltage is adjusted, sensor calibration experiment is carried out in temperature and humidity environment in nitrogen dioxide gas to be measured; experiment is performed based on segmental interpolation technology The calibration data is interpolated to obtain the interpolation data; all the data including the experimental calibration data and interpolation data are composed of the nitrogen dioxide gas concentration measurement database, and the single-value gas-sensing characteristics, single-value temperature-sensing characteristics, Single-value humidity sensitivity characteristics; according to the data in the nitrogen dioxide gas concentration measurement database, based on the segmental interpolation technology and data fusion technology, eliminate the influence of temperature and humidity, and establish an accurate measurement model for the concentration of nitrogen dioxide gas sensors; The output of the sensor array is input into the nitrogen dioxide gas concentration measurement model in real time, and the actual measurement result of the nitrogen dioxide gas concentration can be obtained. The nitrogen dioxide gas concentration measurement method overcomes the multi-valued non-linear problem of the carbon nanotube film two-electrode sensor's gas-sensing characteristics and humidity-sensing characteristics, requires a simple hardware structure, can measure nitrogen dioxide gas, and adopts a data fusion algorithm. Low, high gas detection sensitivity, high accuracy, suitable for popularization and use.

The nitrogen dioxide gas concentration detection method of the invention can realize the concentration measurement of the nitrogen dioxide gas, and the accuracy is 1%. Compared with the gas concentration detection method of the traditional three-electrode detector used in the existing ionization detector chromatograph, this new gas concentration detection method has high sensitivity to nitrogen dioxide gas due to the use of carbon nanotube films as electrodes and a concentration measurement accuracy of 1%. In addition, the carbon nanotube film ionization sensor can reduce the working voltage of the sensor from the high voltage of 600 volts of the ionization detector to a safe and practical range below 200 volts with the nanoscale tip curvature radius of the carbon nanotubes. The novel nitrogen dioxide gas concentration measurement method of the present invention integrates sensor array technology with different pole spacing, pA level current measurement technology, segmental interpolation technology and data fusion technology, which can eliminate the influence of temperature and humidity, and can realize Accurate measurement of nitrogen gas concentration.

Description of drawings

Fig. 1 is a schematic structural diagram of a carbon nanotube film cathode two-electrode sensor in the prior art.

Fig. 2 shows the multi-valued nonlinear gas sensing characteristics of the breakdown voltage and gas concentration of the carbon nanotube film two-electrode gas sensor in the prior art.

Fig. 3 is the non-linear multi-valued gas sensing characteristics of the breakdown current and gas concentration of the carbon nanotube film two-electrode gas sensor in the prior art.

Fig. 4 is the structural representation of carbon nanotube thin film ionization nitrogen dioxide sensor of the present invention;

Fig. 5 is a side view of the three-dimensional structure of the carbon nanotube film ionized nitrogen dioxide sensor of the present invention.

Fig. 6 is the single-value relationship between the gas discharge ion current output by the carbon nanotube film ionization nitrogen dioxide sensor of the present invention and the nitrogen dioxide gas concentration;

In the figure: 1, the first electrode; 2, the second electrode; 3, the third electrode; 4, the electrode provided with air holes; 5, the metal film substrate; 6, the carbon nanotube film; 7, the insulating support.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Example 1

As shown in Fig. 4 and Fig. 5, the carbon nanotube thin film ionized nitrogen dioxide sensor includes three electrodes stacked from top to bottom in sequence, and the three stacked electrodes are respectively provided with a first electrode 1, The second electrode 2 and the third electrode 3, the first electrode is composed of a metal film substrate 5 with a carbon nanotube thin film attached to the inner surface and an electrode 4 with air holes; The third electrode 3 is composed of a collector with blind holes on the surface of the electrode plate; the three electrodes are separated from each other by insulating pillars 7 respectively.

In the carbon nanotube thin film ionized nitrogen dioxide sensor embodiment shown in Fig. 4, there are 2 vent holes on the electrode surface of the first electrode 1, and the vent holes are circular; The film substrate 5 is distributed with a carbon nanotube thin film 6 , and the carbon nanotube tube mouth is downward. The center of the second electrode 2 is provided with 1 to 4 lead-out holes. Figure 4 and Figure 5 show an embodiment in which one lead-out hole is provided and the lead-out hole is circular. The third electrode 3 collector blind hole corresponds to the lead-out hole of the second electrode, and the number of blind holes is 1 to 4. Figures 4 and 5 show the configuration of setting a blind hole and the blind hole is a cylindrical structure. Example. The insulating pillars 7 are arranged between the metal film base 5 and the second electrode 2 and between the second electrode 2 and the third electrode 3 respectively, that is, the insulating pillars 7 are distributed on the second electrode 2 facing the second electrode. The two sides of the surface of the first electrode 1 and the two sides of the inner gold film surface of the third electrode 3 .

The first electrode 1 of the present invention is made of a silicon chip material, and a metal film substrate 5 is attached to the surface of the first electrode 1; the carbon nanotube film 6 can use iron phthalocyanine as a catalyst, and adopts a carbon source, in The carbon nanotube film 6 is grown on the metal film substrate 5 , or the carbon nanotube film 6 is screen printed. Both the second electrode 2 and the third electrode 3 are made of silicon wafers. Metal films are provided on the inner surfaces of the first electrode 1 and the third electrode 3 and on both sides of the second electrode 2 .

There are two air holes on the electrode in the first electrode 1 of the present invention, which is convenient for the gas to be detected to enter the electrode gap; the metal film substrate 5 is attached to the surface of the first electrode 1; the second electrode 2 has an extraction hole; the third electrode 3 The collector can collect the positive ion flow generated by gas ionization. Between the first electrode 1 and the second electrode 2, between the second electrode 2 and the third electrode 3 are isolated from each other by insulating pillars 7; the gas to be measured enters the gap between two adjacent electrodes of the sensor through the gap between the peripheral electrodes of the sensor .

When the carbon nanotube film ionization nitrogen dioxide sensor with the above-mentioned structure is used in the present invention to measure the concentration of nitrogen dioxide gas, the potential of the second electrode is higher than the potential of the first electrode, and the potential of the third electrode is lower than the potential of the second electrode and higher than the potential of the first electrode. an electrode potential. The second electrode forms an electron flow loop with the first electrode, and the third electrode forms an ion flow loop with the first electrode, so as to separate the electron flow from the ion flow. Between the ion flow output by the carbon nanotube film ionization sensor and the nitrogen dioxide gas concentration, gas temperature and humidity, on the basis of applying a certain voltage to the second electrode, there is a single value gas concentration sensitive relationship (Figure 6), single value Temperature-sensitive relationship, single-value humidity-sensitive relationship. Through segmental interpolation and data fusion, the measurement accuracy of nitrogen dioxide gas concentration is 1%. The carbon nanotube thin film ionization sensor array technology with different pole spacing, pA level current measurement technology, segmental interpolation technology and data fusion technology are the characteristics of the concentration measurement method of the present invention.

The method for detecting the concentration of nitrogen dioxide gas by the carbon nanotube film ionization nitrogen dioxide sensor of the present invention will be further described through a specific example.

Using a carbon nanotube film ionized nitrogen dioxide sensor with a fixed pole spacing, the experiment obtained the single-value gas-sensing characteristics of a single gas nitrogen dioxide (as shown in Figure 6), and the nitrogen dioxide sensor output ion current input data fusion established The concentration measurement model obtains the measurement value of the single gas nitrogen dioxide gas concentration with an accuracy of less than 1%.

In the embodiment of the carbon nanotube film ionization nitrogen dioxide sensor shown in FIG. 6 detecting the concentration of nitrogen dioxide gas, the experimental environment conditions are temperature 40.7°C, relative humidity 18.5%RH, and atmospheric pressure 93.5KPa. The carbon nanotube thin film ionization nitrogen dioxide sensor has three electrodes with an electrode spacing of 200 μm between two adjacent electrodes; the carbon nanotube thin film ionization sensor for temperature monitoring has an electrode spacing of 170 μm; for humidity monitoring The distance between adjacent electrodes of the carbon nanotube film ionization sensor is 200 μm and 100 μm, respectively. For the three carbon nanotube thin film ionization sensors, the facing area of the first electrode 1 and the second electrode 2 is 170 mm ² , and the facing area of the second electrode 2 and the third electrode 3 is 190 mm ² . The cathode voltage of the first electrode 1 of the nitrogen dioxide sensor is 0V, the lead-out electrode of the second electrode 2 is loaded with a voltage of 130V, and the collector of the third electrode 3 is loaded with a voltage of 10V. The voltages of the first, second and third electrodes of the temperature sensor are 0V, 70V and 10V respectively; the voltages of the first, second and third electrodes of the humidity sensor are 0V, 90V and 10V respectively. As the concentration of nitrogen dioxide gas increases, the ion flow collected by the collector decreases, and the ion flow shows a single value decrease relationship with the increase of nitrogen dioxide concentration; the sensitivity characteristics of temperature and humidity sensors are similar to those of nitrogen dioxide sensors. In the concentration range of 0-734.795ppm nitrogen dioxide, 10 sets of experimental calibration data were obtained. The ion current values of the three sensors are used as input samples, and the calibration value of the nitrogen dioxide concentration of a single gas is used as the expected output sample data. Linear interpolation is used to interpolate the data of 10 sets of experimental calibration samples. In the concentration range of 0-734.795ppm, the interpolation is performed at equal intervals at 5ppm intervals, and dense interpolation is performed near the attention value (ie, the gas concentration critical value), and a total of 266 sets are obtained. Interpolation data, and 10 sets of experimental data to form a database; 266 sets of interpolation data and 1 set of experimental calibration data, a total of 267 sets of data were selected as training samples, and 9 sets of experimental data were used as test samples, using data fusion technology to obtain the concentration of nitrogen dioxide gas Measurement model. The linearity of the nitrogen dioxide concentration measurement model is 0.185%, and the maximum quoted error of the test results of the 9 groups of test samples is 0.187%, reaching the measurement accuracy of 1% nitrogen dioxide concentration.

Example 2

The basic structure of this embodiment is the same as that of Embodiment 1, except that the distance between the three electrodes of the carbon nanotube film ionization nitrogen dioxide sensor is 250 μm and 30 μm respectively, and the first electrode 1 and the second electrode The facing area of the plates of the second electrode 2 is 0.01 mm ² , and the facing area of the plates of the second electrode 2 and the third electrode 3 is 0.01 mm ² .

There is one vent hole on the electrode surface of the first electrode 1, and the vent hole is quadrilateral, pentagonal or hexagonal; the second electrode 2 has 4 center lead-out holes, and the lead-out holes are quadrilateral, pentagonal or hexagonal ; The number of blind holes in the third electrode 3 is 4, and the blind holes are 3-6 prisms or pyramids.

The detection method of the present embodiment is basically the same as embodiment 1, the difference is:

The cathode voltage of the first electrode of the carbon nanotube thin film ionization nitrogen dioxide sensor is 0V, the second electrode is loaded with a voltage of 2V, and the third electrode is loaded with a voltage of 1V.

Example 3

The basic structure of this embodiment is the same as that of Embodiment 1, the difference is that: among the three electrodes of the carbon nanotube film ionized nitrogen dioxide sensor, the electrode spacing between two adjacent electrodes is 250 μm and 30 μm respectively, and the first electrode 1 and The facing area of the plates of the second electrode 2 is 10 mm ² , and the facing area of the plates of the second electrode 2 and the third electrode 3 is 100 mm ² .

There are 4 vent holes on the electrode surface of the first electrode 1, and the vent holes are quadrilateral, pentagonal or hexagonal; the second electrode 2 has 2 central lead-out holes, and the lead-out holes are quadrilateral, pentagonal or hexagonal ; The number of blind holes in the third electrode 3 is 2, and the blind holes are 3-6 prisms or pyramids.

The detection method of the present embodiment is basically the same as embodiment 1, the difference is:

The cathode voltage of the first electrode of the carbon nanotube thin-film ionization nitrogen dioxide sensor is 0V, the second electrode is loaded with a voltage of 200V, and the third electrode is loaded with a voltage of 180V.

In the present invention, a sensor array is composed of carbon nanotube film ionization sensors with different pole spacings, a pA-level current measurement system detects sensor output, segmental interpolation and data fusion methods, forming a new type that can measure nitrogen dioxide gas and has strong anti-interference ability , High-accuracy nitrogen dioxide gas concentration measurement method. Sensors with different pole spacing in the sensor array can detect the interference effect of temperature and humidity in real time, and directly detect the concentration of nitrogen dioxide gas; the pA current measurement system can simultaneously detect the pA output by each sensor corresponding to the concentration of nitrogen dioxide gas, temperature and humidity Level current; segmental interpolation and data fusion methods, which can eliminate temperature and humidity interference, and output high-accuracy nitrogen dioxide gas concentration measurement values.

Although the present invention has been described in detail with the above preferred embodiments, the above embodiments are not intended to limit the present invention. Without departing from the technical features and structural scope provided by the technical solution of the present invention, any addition, deformation or replacement of the technical features with the same content in the field shall belong to the protection scope of the present invention.

Claims (5)

1. carbon nano-tube film ionization type nitrogen dioxide sensor, it is characterized in that: comprise three the first electrode, the second electrode and third electrodes that distribute successively from top to bottom, the electrode that described the first electrode adheres to the metallic film base that the carbon nano-tube film that distributing is arranged by inside surface and is provided with bleeder vent consists of; The second electrode is made of the extraction pole pole plate that the center is provided with fairlead; Third electrode is made of the collector that the plate face is provided with blind hole; These three electrodes are isolated mutually by insulation column respectively.

2. carbon nano-tube film ionization type nitrogen dioxide sensor according to claim 1, it is characterized in that: adjacent two interelectrode die openings are 30 ~ 250 μ m in described three electrodes; Described the first electrode and the second electrode pad are 0.01 ~ 170mm over against area ², the second electrode and third electrode pole plate are 0.01 ~ 190mm over against area ²

3. carbon nano-tube film ionization type nitrogen dioxide sensor according to claim 1, it is characterized in that: the bleeder vent of the electrode surface of described the first electrode is 1 ~ 4, and the metallic film base growth or the screen printing that adhere at the first electrode inner surface are brushed with carbon nano-tube film;

Described the second electrode extraction pole center is provided with 1 ~ 4 fairlead;

Described third electrode collector blind hole is corresponding with the fairlead of the second electrode, and the quantity of blind hole is 1 ~ 4.

4. based on the nitrogen dioxide gas concentration measuring method of carbon nano-tube film ionization type nitrogen dioxide sensor as claimed in claim 1, it is characterized in that, the method comprises the steps:

(1) die opening of three adjacent two electrodes of electrode of selection is set as the carbon nano-tube film ionization type nitrogen dioxide sensor of 30 ~ 250 μ m;

The carbon nano-tube film ionization type nitrogen dioxide sensor of three different poles spacings (2) will setting respectively, carbon nano-tube film ionization type temperature sensor and carbon nano-tube film ionization type humidity sensor are placed in the atmosphere that contains nitrogen dioxide gas to be measured;

(3) be 0V to the first electrode on-load voltage of three carbon nano-tube film ionization type nitrogen dioxide sensors, carbon nano-tube film ionization type temperature sensor and carbon nano-tube film ionization type humidity sensor respectively, the second electrode on-load voltage 2 ~ 200V, third electrode on-load voltage 1 ~ 180V;

(4) in nitrogen dioxide gas concentration to be measured, temperature and humidity measurement range, corresponding different concentration, temperature and humidity calibration value, respectively the gas discharge ion flow valuve of all the sensors output in the measuring process (2);

(5) with all the sensors output ion flow valuve that in concentration, temperature and humidity measurement range, records in the step (4), with corresponding nitrogen dioxide gas concentration, temperature and humidity calibration value, form different samples, form different experimental calibration samples, then adopt the piecewise interpolation technology that the experimental calibration sample is carried out interpolation, obtain interpolated data, obtain interpolated sample, and set up the nitrogen dioxide gas concentration measured database according to all samples that comprised experimental calibration sample and interpolated sample;

(6) adopt Data fusion technique, make up the data fusion instrument, set up the measurement model of nitrogen dioxide sensor, temperature sensor and humidity sensor; With input sample and the desired output sample of the data in the nitrogen dioxide gas concentration measured database as the data fusion instrument, and train and check as training sample and the test samples of data fusion instrument respectively with data different in the range ability, when assay satisfies the measurement error requirement, the concentration Measurement accuracy model of data fusion instrument output nitrogen dioxide sensor;

The nitrogen dioxide gas concentration Measurement accuracy model that the ion flow valuve input step (6) of output obtains during (7) with carbon nano-tube film ionization type nitrogen dioxide sensor, carbon nano-tube film ionization type temperature sensor and the actual measurement of carbon nano-tube film ionization type humidity sensor, the Measurement accuracy value of this model output nitrogen dioxide gas concentration;

In the described carbon nano-tube film ionization type nitrogen dioxide sensor, the second electrode potential is higher than the first electrode potential, and the third electrode current potential is lower than the second electrode potential and is higher than the first electrode potential.

5. the nitrogen dioxide gas concentration measuring method based on carbon nano-tube film ionization type nitrogen dioxide sensor according to claim 4, it is characterized in that: the described nitrogen dioxide gas concentration measured database of setting up, that experimental calibration data and interpolated data are formed database, with each sensor output ion flow valuve and interpolated data thereof as the input sample, with nitrogen dioxide gas concentration, temperature and humidity calibration value and interpolated data thereof as the desired output sample.

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