JP2003004671A - Substance identifying method and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new substance identifying method capable of identifying an orientation sample with high accuracy. SOLUTION: By comparing a reference data base in which two-dimensional X-ray diffraction line data of an equatorial direction (2θdirection) and a Debye ring direction (β direction) on a plurality of substances is stored with two-dimensional X-ray diffraction line data of the equatorial direction and the Debye ring direction on substance to be measured, the substance to be measured is identified.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a substance identification method and a substance identification system. More specifically, the invention of this application relates to a new substance identification method and substance identification system, which is useful for identifying not only non-oriented samples but also oriented samples, by two-dimensional measurement of X-ray diffraction. .

[0002]

The inventors of the invention of this application have already proposed a method for identifying a substance by powder X-ray diffraction measurement (Japanese Patent No. 2908530). This substance identification method was made in order to solve the problem of the substance identification method using the conventional JCPDS card, and the information on the curve shape of the X-ray diffraction pattern was created as a standard database and measured. The substance to be measured is identified by comparing the X-ray diffraction pattern of the substance with this standard database. This makes it possible to easily and accurately identify a substance composed of a complicated mixture, a substance containing an incomplete crystal, a distorted crystal, or the like.

[0003]

However, further studies by the inventor of the invention of this application have revealed that even such an excellent method for identifying substances has some points to be improved.

That is, in the conventional substance identification method, since the identification is performed by using the powder diffraction pattern as a target, the crystals are aligned in a specific direction, that is, the orientation, such as a polymer material or metal which is not powdered, by the manufacturing method. For samples that are often in a state, the powder diffraction pattern differs depending on the mounting condition of the sample (the stronger the orientation, the more remarkable this phenomenon), and the identification accuracy becomes lower than that of the non-oriented sample. is there.

In view of the circumstances as described above, the invention of this application provides a novel substance identification method and a substance identification system for executing the same, which can identify an oriented sample with high accuracy. It is an issue.

[0006]

In order to solve the above-mentioned problems, the invention of this application solves the above-mentioned problems by using a standard database storing two-dimensional X-ray diffraction line data of a plurality of substances in the equatorial direction and the Debye ring direction, and a substance to be measured. Substance identification method (claim 1), characterized in that the substance to be measured is identified by comparing the two-dimensional X-ray diffraction line data in the equatorial direction and the Debye ring direction of Standard database storing profile data of X-ray diffraction intensity for the equatorial direction in which the average value of X-ray diffraction intensity in the X-ray direction is calculated, and X-ray in the equatorial direction for calculating the average value of X-ray diffraction intensity in the Debye ring direction of the measured substance A substance identification method (claim 2) characterized in that the substance to be measured is identified by comparing it with profile data of diffraction intensity. A standard database that stores two-dimensional X-ray diffraction line data in the equatorial direction and the Debye ring direction for a plurality of substances, and profile data of the X-ray diffraction intensity for the equatorial line direction in which the average value of the X-ray diffraction intensity in the Debye ring direction is calculated. First comparison with profile data of X-ray diffraction intensity with respect to the equatorial direction in which the average value of X-ray diffraction intensity in the Debye ring direction of the substance to be measured is calculated, and with two-dimensional X-ray diffraction line data in the equatorial direction and the Debye ring direction A substance identification method (claim 3) characterized in that a substance to be measured is identified by performing a second comparison.

In the invention of this application, in the above-mentioned substance identification method, two-dimensional X-ray diffraction line data are compared with each other.
The two-dimensional X-ray diffraction line data is cut out into a plurality of circular arc data, which is performed for each circular arc data (Claim 4), and the correlation coefficient is used for comparison between each data in the standard database and each data of the substance to be measured. (Claim 5) is also provided.

Furthermore, the invention of this application is provided with a two-dimensional detector and an identification device for identifying a substance to be measured using the substance identification method according to any one of claims 1 to 5. Also provided is a substance identification system (claim 6) that

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The invention of this application has the characteristics as described above, and the embodiments thereof will be described in detail below with reference to the accompanying drawings.

[0010]

EXAMPLES The invention of this application is based on the fact that two-dimensional X-ray diffraction lines (see FIG. 1) in the equatorial direction (= 2θ direction) and the Debye ringing direction (= β direction) of various reference substances are preliminarily analyzed.
(= Image plate), CCD (= charge coupled device),
Two-dimensional PSPC (= position-sensitive proportional counter), two-dimensional detectors such as photographs are used for measurement, and these are stored as standard data in a standard database. The sample is identified by comparing the two-dimensional X-ray diffraction line data in the ring direction with the two-dimensional X-ray diffraction line data in the standard database.

The two-dimensional X-ray diffraction line data in the equatorial direction and the Debye ring direction is obtained by measuring the orientation state of the sample as it is. By comparing the orientation states, the orientation sample can be identified with high accuracy. You can That is, the invention of this application does not remove the influence of the orientation but positively uses the orientation.

By the way, since two-dimensional data naturally has a larger amount of information than one-dimensional data, enormous processing is required.
Therefore, in the invention of this application, based on the two-dimensional X-ray diffraction line data, the profile data of the X-ray diffraction intensity for the equatorial direction calculated with the specified width of the average value of the X-ray diffraction intensity in the Debye ring direction is created. , The sample is identified by storing it in a standard database and comparing similar profile data created based on the two-dimensional X-ray diffraction line data measured for the sample with the profile data in the standard database. You can also FIG. 2 is a schematic diagram illustrating the Debye ring direction data and profile data obtained by converting the data.

Since the profile data is obtained by converting the two-dimensional X-ray diffraction line data into one-dimensional data, it is of course possible to suppress the processing amount and accelerate the identification speed, and also the identification accuracy of the oriented sample is sufficiently high. Can be expensive.

Furthermore, in the invention of this application, both the two-dimensional X-ray diffraction line data and the profile data are stored in a standard database, for example, the former as standard data and the latter as sub-standard data. A first comparison is made between the profile data and the profile data for the sample, and a second comparison is made between the two-dimensional X-ray diffraction line data of the standard substance and the two-dimensional X-ray diffraction line data of the sample retrieved by the first comparison. May be.

By this two-step comparison, comparative identification based on one-dimensional data is carried out, and in order to make it reliable, 2
Since it is sufficient to perform the comparative identification based on the dimension data, it is possible to reduce the throughput and to identify the sample more accurately.

In this case, the degree of agreement in the first comparison is set to have a certain range so that a plurality of standard substances can be extracted (so-called screening). If the second comparison is performed using the second comparison, a standard substance having a high degree of agreement can be more easily found.

In comparison with the standard database, 2
The two-dimensional X-ray diffraction line data can be compared with each other, for example, by cutting the two-dimensional X-ray diffraction line data into a plurality of arc data as illustrated in FIG.
The arc data may be cut out at regular intervals or at random intervals.

Then, the cut-out circular arc data are compared with each other using, for example, a correlation coefficient. Of course, the correlation coefficient can be used to compare the profile data with each other.
The possibility of agreement is shown by arranging in order of increasing correlation coefficient.

The substance identification method of the invention of the above application is as follows:
The measurement of the two-dimensional X-ray diffraction line data is performed by a two-dimensional detector, but the computer creates the profile data based on the obtained two-dimensional X-ray diffraction line data and compares the data. Therefore, according to the substance identification system including the two-dimensional detector and the computer as the identification device, it is possible to automatically identify the substance.
Of course, it is preferable to construct so that the measurement values from the two-dimensional detector can be transmitted to the computer. Also, even if the standard database is built in the storage means of the computer,
Needless to say, it may be a separate database device, and in the latter case, for example, data communication with a computer is possible as illustrated in FIG.

In the two-dimensional X-ray diffraction measurement using the two-dimensional detector, the orientation may be deviated depending on how the orientation sample is attached. Therefore, it is preferable to rotate this correction in a direction in which symmetry occurs. For example, a sample having a fiber orientation such as a fiber sample has good symmetry, so that the measurement as illustrated in FIG. Therefore, when the sample is rotated to a position where its symmetry appears, that is, a correlation appears, the measurement data illustrated in FIG. 5B is obtained, and accurate comparison is always possible.

Of course, it goes without saying that more details of the invention of this application are possible.

[0022]

As described in detail above, the invention of this application provides a new substance identification method and substance identification system which can identify an oriented sample with high accuracy.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a substance identification method of the invention of this application.

FIG. 2 is a diagram for explaining Debye ring direction data and profile data obtained by converting the data.

FIG. 3 is a diagram for explaining cutting out of arc data.

FIG. 4 is a block diagram showing an example of a substance identification system of the invention of this application.

5 (a) and 5 (b) are diagrams for explaining rotation of an oriented sample.

Claims (6)

[Claims] 1. A standard database in which two-dimensional X-ray diffraction line data in the equatorial direction and debye ringing direction of a plurality of substances are stored and two-dimensional x-ray diffraction line data in the equatorial direction and the debye ringing direction of a substance to be measured are stored. A substance identification method characterized in that a substance to be measured is identified by comparison. 2. A standard database storing profile data of X-ray diffraction intensities with respect to the equatorial direction, in which average values of X-ray diffraction intensities in the Debye ring direction of a plurality of substances are stored, and X-ray diffraction in the Debye ring direction of a substance to be measured. A substance identification method, characterized in that the substance to be measured is identified by comparing the profile data of the X-ray diffraction intensity with respect to the equatorial direction in which the intensity average value is calculated. 3. The two-dimensional X-ray diffraction line data in the equatorial direction and the Debye ring direction and the profile data of the X-ray diffraction intensity in the equatorial line direction in which the average value of the X-ray diffraction intensity in the Debye ring direction is calculated for a plurality of substances. First comparison between the stored standard database and profile data of X-ray diffraction intensity with respect to the equatorial direction in which the average value of X-ray diffraction intensity in the Debye ring direction of the measured substance is calculated, and two-dimensional X-rays in the equatorial direction and the Debye ring direction A substance identification method characterized in that a substance to be measured is identified by performing a second comparison with diffraction line data. 4. Comparison of two-dimensional X-ray diffraction line data with each other
The substance identification method according to claim 1 or 3, wherein the two-dimensional X-ray diffraction line data is cut out into a plurality of pieces of arc data, and each piece of arc data is cut out. 5. The correlation coefficient is used to compare each data in the standard database with each data of the substance to be measured.
5. The substance identification method according to any one of 1 to 4. 6. A two-dimensional detector, and any one of claims 1 to 5.
2. A substance identification system, comprising: an identification device that identifies a substance to be measured using any one of the substance identification methods described above.