阅读说明：本技术 基于太赫兹介电谱的阿胶含水量检测方法及系统 (Donkey-hide gelatin water content detection method and system based on terahertz dielectric spectrum ) 是由 张献生 常天英 刘陵玉 李羿璋 崔洪亮 于 2020-12-09 设计创作，主要内容包括：本发明提供一种基于太赫兹介电谱的阿胶含水量检测方法及系统,属于含水量检测技术领域,获取与待检测阿胶相同批次的标准干燥阿胶的介电常数、待检测阿胶的介电常数以及水的介电常数；结合有效介质模型,根据标准干燥阿胶的介电常数、待检测阿胶的介电常数以及水的介电常数计算待检测阿胶中水分的体积系数；根据水分的体积系数计算待检测阿胶的含水量。本发明只需测试待检测阿胶、标准干燥阿胶和水的介电常数,利用有效介质模型,以干燥阿胶的介电常数为基准,计算待检测阿胶的含水量,缩短了测试时间,降低了检测成本,提高了生产效率；实现对测试样品的非接触无损测量,操作方便快速、测量频率宽、精确度高、测量值波动范围小,提高了产品质量。(The invention provides a method and a system for detecting the water content of donkey-hide gelatin based on a terahertz dielectric spectrum, belonging to the technical field of water content detection, and the method comprises the steps of obtaining the dielectric constant of standard dried donkey-hide gelatin in the same batch as the donkey-hide gelatin to be detected, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water; calculating the volume coefficient of water in the donkey-hide gelatin to be detected according to the dielectric constant of the standard dry donkey-hide gelatin, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water by combining an effective medium model; and calculating the water content of the donkey-hide gelatin to be detected according to the volume coefficient of the water. The method only needs to test the dielectric constants of the donkey-hide gelatin to be tested and the standard dried donkey-hide gelatin and water, and calculates the water content of the donkey-hide gelatin to be tested by using the effective medium model and taking the dielectric constant of the dried donkey-hide gelatin as a reference, so that the test time is shortened, the test cost is reduced, and the production efficiency is improved; the non-contact nondestructive measurement of the test sample is realized, the operation is convenient and quick, the measurement frequency is wide, the accuracy is high, the fluctuation range of the measured value is small, and the product quality is improved.)

1. A method for detecting the water content of donkey-hide gelatin based on terahertz dielectric spectroscopy is characterized by comprising the following steps:

acquiring the dielectric constant of standard dried donkey-hide gelatin of the same batch as the donkey-hide gelatin to be detected, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water;

calculating the volume coefficient of water in the donkey-hide gelatin to be detected according to the dielectric constant of the standard dry donkey-hide gelatin, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water by combining an effective medium model;

and calculating the water content of the donkey-hide gelatin to be detected according to the volume coefficient of the water.

2. The method for detecting water content of donkey-hide gelatin based on terahertz dielectric spectroscopy as claimed in claim 1, wherein calculating the dielectric constant of standard dried donkey-hide gelatin of the same batch as the donkey-hide gelatin to be detected comprises:

preparing colla Corii Asini to be detected into powder, drying the powder in a vacuum drier to constant weight, cooling to room temperature, and drying to obtain standard dried colla Corii Asini; tabletting the standard dried donkey-hide gelatin, placing the standard dried donkey-hide gelatin again in a vacuum drier at room temperature for drying, sealing and wrapping the standard dried donkey-hide gelatin by using a film, and testing the terahertz complex refractive index and the extinction coefficient of the standard dried donkey-hide gelatin by using a terahertz time-domain spectrometer; the dielectric constant of the standard dried donkey-hide gelatin is calculated from the terahertz complex refractive index and the extinction coefficient of the standard dried donkey-hide gelatin.

3. The method for detecting water content of donkey-hide gelatin based on terahertz dielectric spectroscopy as claimed in claim 1, wherein calculating the dielectric constant of donkey-hide gelatin to be detected comprises:

preparing a certain mass of donkey-hide gelatin to be detected into powder, sieving the powder, tabletting the powder, sealing and wrapping the powder by using a film, and testing the terahertz complex refractive index and the extinction coefficient of the donkey-hide gelatin to be detected in a terahertz time-domain spectrometer; and calculating the dielectric constant of the donkey-hide gelatin to be detected according to the terahertz complex refractive index and the extinction coefficient of the donkey-hide gelatin to be detected.

4. The method for detecting the water content of donkey-hide gelatin based on terahertz dielectric spectroscopy as claimed in claim 3, wherein the step of counting the water content while the water loss of the sieved donkey-hide gelatin after being prepared into powder comprises: placing the donkey-hide gelatin to be detected in a powder grinding machine for grinding, weighing a sample box of the powder grinding machine and the donkey-hide gelatin to be detected together, weighing again after grinding, calculating the mass difference of the two weighing, and counting the mass difference into the water content; and (3) screening the powder by using a 100-mesh screen, weighing the mass difference before and after screening, and counting the water content.

5. The method for detecting water content of donkey-hide gelatin based on terahertz dielectric spectroscopy as claimed in claim 1, wherein calculating the dielectric constant of water comprises: calculating the dielectric constant of water under different frequencies according to a second-order DE-Bay equation, wherein the calculation formula is as follows:wherein epsilon_∞Denotes the dielectric constant, ε, at infinite frequency_sDenotes the dielectric constant, ε, at zero frequency₁Denotes the dielectric constant, τ, at an intermediate frequency₁Denotes the slow relaxation time constant, τ₂Representing the fast relaxation time constant and theta the angular frequency.

6. The method for detecting water content of donkey-hide gelatin based on terahertz dielectric spectroscopy as claimed in claim 1, wherein the effective medium model is:

wherein is epsilon'_{General assembly}(omega) represents the dielectric constant, epsilon 'of the donkey-hide gelatin to be detected'_{Dry matter}(ω) represents the dielectric constant, ε'_{Water (W)}(ω) represents the dielectric constant of water, α₁Represents the volume coefficient, alpha, of the donkey-hide gelatin component in the donkey-hide gelatin to be detected₂Represents the volume coefficient of the moisture in the donkey-hide gelatin to be detected.

7. The method for detecting moisture content of colla Corii Asini based on terahertz dielectric spectroscopy as claimed in claim 6, wherein α is calculated by multiple linear regression algorithm₁And alpha₂The value of (c):

y＝α₁x₁+α₂x₂+δ；

wherein y is a dependent variable, i.e. to be detectedDielectric constant of donkey-hide gelatin, x₁、x₂Is the independent variable, i.e., the dielectric constant of standard dry gum and water, and the error term δ follows a normal distribution (0, 1).

8. The method for detecting the water content of donkey-hide gelatin based on terahertz dielectric spectroscopy as claimed in claim 2 or 3, wherein the dielectric constant is calculated according to the terahertz complex refractive index and the extinction coefficient as follows:

ε′_r(ω)＝n(ω)²-k(ω)²

ε″_r(ω)＝2n(ω)×k(ω)

wherein is epsilon'_r(ω)、ε″_rAnd (omega), n (omega) and k (omega) respectively represent a real dielectric constant part, an imaginary dielectric constant part, a real refractive index part and an extinction coefficient.

9. A donkey-hide gelatin water content detecting system based on terahertz dielectric spectrum is characterized by comprising:

the acquisition module is used for acquiring the dielectric constant of standard dried donkey-hide gelatin of the same batch as the donkey-hide gelatin to be detected, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water;

the first calculation module is used for calculating the volume coefficient of water in the donkey-hide gelatin to be detected according to the dielectric constant of the standard dry donkey-hide gelatin, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water by combining the effective medium model;

and the second calculation module is used for calculating the water content of the donkey-hide gelatin to be detected according to the volume coefficient of the water.

Technical Field

The invention relates to the technical field of water content detection, in particular to a method and a system for detecting the water content of donkey-hide gelatin based on terahertz dielectric spectroscopy.

Background

The donkey-hide gelatin is used as a traditional Chinese medicine component, has the effects of tonifying kidney, strengthening bone, inducing diuresis and reducing edema, has good application effect in preventing and treating various diseases, has more than two thousand years of use history in China, and the water content of a donkey-hide gelatin finished product is required to be not higher than 15% in Chinese pharmacopoeia. The donkey-hide gelatin is decocted to obtain a solid block from liquid, and the steps of long-time natural airing, microwave drying and the like are required to ensure that the water content of the donkey-hide gelatin reaches the requirements of pharmacopeia. At present, a drying method recommended by pharmacopoeia is generally adopted in the detection of the water content of the donkey-hide gelatin. Namely, a plurality of grams of donkey-hide gelatin are heated and dried for a plurality of hours, then are cooled and weighed, are continuously heated and dried, and then are cooled and weighed, and the detection is considered to be finished when the weight of the donkey-hide gelatin does not exceed 2mg in two times. This method takes a minimum of 6 hours and takes a long time.

Disclosure of Invention

The invention aims to provide a method and a system for detecting the water content of donkey-hide gelatin based on terahertz dielectric spectroscopy, which can quickly and accurately detect the water content of the donkey-hide gelatin, so as to solve at least one technical problem in the background technology.

In order to achieve the purpose, the invention adopts the following technical scheme:

in one aspect, the invention provides a method for detecting the water content of donkey-hide gelatin based on terahertz dielectric spectroscopy, which comprises the following steps:

acquiring the dielectric constant of standard dried donkey-hide gelatin of the same batch as the donkey-hide gelatin to be detected, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water;

calculating the volume coefficient of water in the donkey-hide gelatin to be detected according to the dielectric constant of the standard dry donkey-hide gelatin, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water by combining an effective medium model;

and calculating the water content of the donkey-hide gelatin to be detected according to the volume coefficient of the water.

Preferably, the calculation of the dielectric constant of the standard dried donkey-hide gelatin of the same lot as the donkey-hide gelatin to be detected comprises:

preparing colla Corii Asini to be detected into powder, drying the powder in a vacuum drier to constant weight, cooling to room temperature, and drying to obtain standard dried colla Corii Asini; tabletting the standard dried donkey-hide gelatin, placing the standard dried donkey-hide gelatin again in a vacuum drier at room temperature for drying, sealing and wrapping the standard dried donkey-hide gelatin by using a film, and testing the terahertz complex refractive index and the extinction coefficient of the standard dried donkey-hide gelatin by using a terahertz time-domain spectrometer; the dielectric constant of the standard dried donkey-hide gelatin is calculated from the terahertz complex refractive index and the extinction coefficient of the standard dried donkey-hide gelatin.

Preferably, the calculating of the dielectric constant of the donkey-hide gelatin to be detected comprises:

preparing a certain mass of donkey-hide gelatin to be detected into powder, sieving the powder, tabletting the powder, sealing and wrapping the powder by using a film, and testing the terahertz complex refractive index and the extinction coefficient of the donkey-hide gelatin to be detected in a terahertz time-domain spectrometer; and calculating the dielectric constant of the donkey-hide gelatin to be detected according to the terahertz complex refractive index and the extinction coefficient of the donkey-hide gelatin to be detected.

Preferably, the step of measuring the water content of the donkey-hide gelatin to be detected by sieving after the donkey-hide gelatin is made into powder comprises the following steps: placing the donkey-hide gelatin to be detected in a powder grinding machine for grinding, weighing a sample box of the powder grinding machine and the donkey-hide gelatin to be detected together, weighing again after grinding, calculating the mass difference of the two weighing, and counting the mass difference into the water content; and (3) screening the powder by using a 100-mesh screen, weighing the mass difference before and after screening, and counting the water content.

Preferably, calculating the dielectric constant of water comprises: calculating the dielectric constant of water under different frequencies according to a second-order DE-Bay equation, wherein the calculation formula is as follows:wherein epsilon_∞Denotes the dielectric constant, ε, at infinite frequency_sDenotes the dielectric constant, ε, at zero frequency₁Denotes the dielectric constant, τ, at an intermediate frequency₁Denotes the slow relaxation time constant, τ₂Representing the fast relaxation time constant and theta the angular frequency.

Preferably, the effective medium model is:

α₁+α₂＝1

wherein is epsilon'_{General assembly}(omega) represents the dielectric constant, epsilon 'of the donkey-hide gelatin to be detected'_{Dry matter}(ω) represents the dielectric constant, ε'_{Water (W)}(ω) represents the dielectric constant of water, α₁Represents the volume coefficient, alpha, of the donkey-hide gelatin component in the donkey-hide gelatin to be detected₂Represents the volume coefficient of the moisture in the donkey-hide gelatin to be detected.

Preferably, alpha is calculated using a multiple linear regression algorithm₁And alpha₂The value of (c):

y＝α₁x₁+α₂x₂+δ；

wherein y is a dependent variable, i.e. the dielectric constant, x, of the donkey-hide gelatin to be detected₁、x₂Is the independent variable, i.e., the dielectric constant of standard dry gum and water, and the error term δ follows a normal distribution (0, 1).

Preferably, the dielectric constant is calculated from the terahertz complex index and the extinction coefficient as:

ε′_r(ω)＝n(ω)²-k(ω)²

ε″_r(ω)＝2n(ω)×k(ω)

wherein is epsilon'_r(ω)、ε″_rAnd (omega), n (omega) and k (omega) respectively represent a real dielectric constant part, an imaginary dielectric constant part, a real refractive index part and an extinction coefficient.

In a second aspect, the present invention provides a system for detecting moisture content of donkey-hide gelatin based on terahertz dielectric spectroscopy, comprising:

the acquisition module is used for acquiring the dielectric constant of standard dried donkey-hide gelatin of the same batch as the donkey-hide gelatin to be detected, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water;

the first calculation module is used for calculating the volume coefficient of water in the donkey-hide gelatin to be detected according to the dielectric constant of the standard dry donkey-hide gelatin, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water by combining the effective medium model;

and the second calculation module is used for calculating the water content of the donkey-hide gelatin to be detected according to the volume coefficient of the water.

The invention has the beneficial effects that: the dielectric constants of the donkey-hide gelatin to be detected, the standard dried donkey-hide gelatin and the water are tested only by the terahertz time-domain spectrometer, the dielectric constant of the dried donkey-hide gelatin is taken as a reference, the effective medium model is utilized, the water content of the donkey-hide gelatin to be detected is calculated, the testing time is greatly shortened, the detecting cost is effectively reduced, and the production efficiency is improved; the non-contact nondestructive measurement of a test sample is ensured, the sample material requirement is low, the operation is convenient and rapid, the measurement frequency is wide, the accuracy is high, the fluctuation range of the measured value is small, and the product quality is improved.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic flow chart of a method for detecting moisture content of donkey-hide gelatin based on terahertz dielectric spectroscopy according to an embodiment of the present invention.

Fig. 2 is a schematic block diagram of a system for detecting moisture content of donkey-hide gelatin based on terahertz dielectric spectroscopy according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of a change curve of a real part of a terahertz dielectric constant of water with a terahertz frequency according to an embodiment of the present invention.

Fig. 4 is a schematic diagram of the dielectric constants of the donkey-hide gelatin to be detected, the standard dried donkey-hide gelatin and water according to the embodiment of the present invention, which change with the thz frequency.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below by way of the drawings are illustrative only and are not to be construed as limiting the invention.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

For the purpose of facilitating an understanding of the present invention, the present invention will be further explained by way of specific embodiments with reference to the accompanying drawings, which are not intended to limit the present invention.

It should be understood by those skilled in the art that the drawings are merely schematic representations of embodiments and that the elements shown in the drawings are not necessarily required to practice the invention.

Example 1

The dielectric response is a phenomenon in which a substance interacts with an electromagnetic wave of a certain frequency, and can be expressed as a dielectric spectrum when depending on the frequency, and main parameters thereof are a complex dielectric constant, a complex conductivity, an absorption coefficient, and the like. The water has strong absorption effect on the terahertz waves, and the difference of the water content has obvious change on the terahertz dielectric response of the donkey-hide gelatin, namely the change of the water content of the donkey-hide gelatin can be reflected by the dielectric spectrum and the absorption. Different from the defect of low resolution of narrow bandwidth of microwave, the terahertz has high bandwidth and high resolution, and the accuracy of detecting the water content of the donkey-hide gelatin can be greatly improved.

The water exists in the donkey-hide gelatin in a free state, pure donkey-hide gelatin dry matter and the water can be used as two effective media according to an effective medium model of the mixture, and the water content of the donkey-hide gelatin can be rapidly and accurately calculated by combining a dielectric response principle. As a spectrum analysis technology for nondestructive testing, the dielectric spectrum technology has great potential and value in field testing application.

The embodiment 1 of the invention provides a method for detecting the water content of donkey-hide gelatin based on terahertz dielectric spectroscopy, which comprises the steps of obtaining the dielectric constant of standard dried donkey-hide gelatin in the same batch as the donkey-hide gelatin to be detected, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water; calculating the volume coefficient of water in the donkey-hide gelatin to be detected according to the dielectric constant of the standard dry donkey-hide gelatin, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water by combining an effective medium model; and calculating the water content of the donkey-hide gelatin to be detected according to the volume coefficient of the water.

The method comprises the following specific operation steps:

1. sampling donkey-hide gelatin to be tested, pulverizing, taking several grams of powder samples, placing the powder samples in a vacuum drier according to the national standard method, drying to constant weight, taking out the powder samples, and cooling to room temperature in the drier.

2. Tabletting the dried colla Corii Asini powder in a box with flowing dry air, wherein the powder weight is 0.2g, the thickness is about 1.2mm, and the pressure is 20MPa,

3. and (4) placing the tabletting-finished donkey-hide gelatin piece again in a vacuum drying oven at room temperature for drying for 2 hours, and then sealing and wrapping the tabletting-finished donkey-hide gelatin piece by using a film.

4. Dry air is filled in the terahertz time-domain spectrometer sample box, so that the humidity of the test environment is lower than 3% and the test environment is kept stable. The sample was placed between the transmitting and receiving probes of the test instrument, and the terahertz complex refractive index of the pressed sheet was measured by the instrument, and the dielectric constant was calculated.

5. 20g of donkey-hide gelatin blocks with unknown water content to be detected are sampled and placed in a powder grinding machine, a sample box of the powder grinding machine and the samples are weighed together, the samples are weighed again after being ground, the mass difference of two times is calculated, and the water content is calculated. Screening with a 100-mesh screen, calculating the mass difference before and after screening, and calculating the water content difference.

6. And after the donkey-hide gelatin powder is tableted, the donkey-hide gelatin powder is hermetically wrapped by a film, so that the moisture is prevented from being lost in the testing process, the film is tightly attached to the surfaces of two sides of the tableted tablet, and the complex refractive index is tested in a dry environment in a terahertz time-domain spectrometer.

7. Calculating the dielectric constants of water and the two donkey-hide gelatins according to related formulas.

8. The real part of the dielectric constant of the water-content donkey-hide gelatin is a dependent variable, the real part of the dielectric constant of the dried donkey-hide gelatin and the water is an independent variable, and a multiple linear regression algorithm is adopted for calculation. E.g. alpha calculated in this example₁、α₂The method comprises the following steps: 0.9679, 0.0289. The density of the dried gum arabic and water was 1.12g/cm³，1.0g/cm³Further, the mass ratio of water in the whole was calculated to be 2.596%, that is, the water content of donkey-hide gelatin was 2.596%, which was different from the actually measured 2.72% by about 0.12%.

9. The real part of the dielectric constant of the dried donkey-hide gelatin is taken as a reference, and the water content of the same donkey-hide gelatin product under any condition can be calculated by only testing the real part of the dielectric constant of the same donkey-hide gelatin product.

Example 2

As shown in fig. 2, embodiment 2 of the present invention provides a system for detecting moisture content of donkey-hide gelatin based on terahertz dielectric spectroscopy, including: the acquisition module is used for acquiring the dielectric constant of standard dried donkey-hide gelatin of the same batch as the donkey-hide gelatin to be detected, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water; the first calculation module is used for calculating the volume coefficient of water in the donkey-hide gelatin to be detected according to the dielectric constant of the standard dry donkey-hide gelatin, the dielectric constant of the donkey-hide gelatin to be detected and the dielectric constant of water by combining the effective medium model; and the second calculation module is used for calculating the water content of the donkey-hide gelatin to be detected according to the volume coefficient of the water.

As shown in fig. 1, the donkey-hide gelatin water content detection system based on terahertz dielectric spectroscopy is used for realizing donkey-hide gelatin water content detection, and the specific operation steps are as follows:

step 1: the method for obtaining the terahertz dielectric spectrum of the donkey-hide gelatin after the complete drying in the same batch comprises the following specific steps: pulverizing colla Corii Asini block with a powder grinding machine, sieving to obtain colla Corii Asini powder with particle size smaller than 100 mesh, drying completely by drying method, and taking out. Tabletting by using a tabletting machine in a closed dry environment, wherein the pressure is 20MPa, the thickness is 0.5-1.0 mm, and the density (weight/volume) of the donkey-hide gelatin is calculated. The tablet is put into a closed space with the humidity less than 3% for testing, a terahertz time-domain spectrometer is used for testing the stable refractive index and extinction coefficient of the tablet donkey-hide gelatin, the frequency range is 0.3-1.0THz, and the dielectric constant is further calculated, wherein the formula is as follows:

ε′_r(ω)＝n(ω)²-k(ω)²

ε″_r(ω)＝2n(ω)×k(ω)

wherein is epsilon'_r(ω)、ε″_rAnd (omega), n (omega) and k (omega) respectively represent a real dielectric constant part, an imaginary dielectric constant part, a real refractive index part and an extinction coefficient.

Step 2: the same batch of donkey-hide gelatin with unknown water content was tested. Selecting a certain amount (20g) of donkey-hide gelatin, grinding and screening, calculating the water loss caused in the grinding and screening process, and counting the water loss into the total water content. After the donkey-hide gelatin powder is pressed into tablets, the tablets are tested under certain humidity, and the films (the thickness is less than 0.02mm) are used for sealing and wrapping the tablets, so that the films are tightly attached to two surfaces of the tablets, the films and the tablets are tightly attached together during testing, the influence caused by air between the films and the tablets is eliminated, and the refractive index and the extinction coefficient of a terahertz frequency band are obtained. The film effect is negligible due to the large difference in thickness between the film and the preform.

And step 3: the terahertz dielectric spectrum of water is calculated.Calculating the dielectric spectrum under different frequencies according to a second order DE-Bay equation, wherein the frequency range is 0.3-1.0THz, and the calculation formula is as follows:wherein epsilon_∞Denotes the dielectric constant, ε, at infinite frequency_sDenotes the dielectric constant, ε, at zero frequency₁Denotes the dielectric constant, τ, at an intermediate frequency₁Denotes the slow relaxation time constant, τ₂Represents the fast relaxation time constant, which in this example 1 are respectively: 78.8, 6.6, 4.1, 10.6 and 0.18, θ is the angular frequency.

As shown in FIG. 3, the graph is a graph showing the variation curve of the real part of the dielectric constant of terahertz of water with the frequency of terahertz. As shown in table 1, a data table of real parts of dielectric constant of water at different thz frequencies is shown.

Table 1:

frequency (TH z)	Real part of relative permittivity
		0.3007	6.04039
0.30512	6.02495
		0.30954	6.00981
0.31396	5.99497
		0.31838	5.98039
0.32281	5.96604
		0.32723	5.95195
0.33165	5.93809
		0.33607	5.92444
0.34049	5.911
		0.34492	5.89771
0.34934	5.88463
		0.35376	5.87172
0.35818	5.85897
		0.3626	5.84637
0.36703	5.83389
		0.37145	5.82157
0.37587	5.80938
		0.38029	5.79731
0.38471	5.78537
		0.38914	5.77351
0.39356	5.76178
		0.39798	5.75015
0.4024	5.73863
		0.40682	5.72719

Fig. 4 is a graph showing the dielectric constant of the donkey-hide gelatin to be detected, the standard dried donkey-hide gelatin and water varying with the thz frequency. As shown in table 2, the data table shows real dielectric constants of the donkey-hide gelatin to be detected (donkey-hide gelatin with unknown water content), the standard dried donkey-hide gelatin and water at different thz frequencies.

TABLE 2

And 4, step 4: calculating the volume ratio of the water content of the donkey-hide gelatin to be detected by using an effective medium model, wherein the effective medium model in the donkey-hide gelatin is as follows:

α₁+α₂＝1

wherein is epsilon'_{General assembly}(omega) represents the dielectric constant, epsilon 'of the donkey-hide gelatin to be detected'_{Dry matter}(ω) represents the dielectric constant, ε'_{Water (W)}(ω) represents the dielectric constant of water, α₁Represents the volume coefficient, alpha, of the donkey-hide gelatin component in the donkey-hide gelatin to be detected₂Represents the volume coefficient of the moisture in the donkey-hide gelatin to be detected.

In the above formula, since dielectric constants at different frequencies are already obtained, the volume coefficient α is calculated by using a multiple linear regression algorithm for multi-sample calculation₁And alpha₂The value of (c). The function model is as follows:

y＝α₁x₁+α₂x₂+δ；

wherein y is a dependent variable, i.e. the dielectric constant, x, of the donkey-hide gelatin to be detected₁、x₂Is the independent variable, i.e., the dielectric constant of standard dry gum and water, and the error term δ follows a normal distribution (0, 1).

From the volume ratio and the respective densities, the mass ratio and the water content, which is the mass ratio of water to the whole, were determined.

The real part of the dielectric constant of the dried donkey-hide gelatin is taken as a reference, and the water content of the same donkey-hide gelatin product under any condition can be calculated by only testing the real part of the dielectric constant of the same donkey-hide gelatin product.

In summary, the method and system for detecting moisture content of donkey-hide gelatin based on terahertz dielectric spectroscopy according to the embodiments of the present invention utilize a terahertz time-domain spectroscopy (THz-TDS) to test the refractive index of sheet donkey-hide gelatin, calculate the corresponding dielectric spectroscopy parameters through a refractive index and dielectric constant calculation formula, and calculate the volume ratio of water through an effective medium model function, thereby realizing the calculation of moisture content. The operation is simple and easy to use, the testing accuracy is high, the tested frequency bandwidth can reach the level of THz (1012Hz), a small change trend can be represented under a wide frequency band, the manufacturing requirement on the sample is low, and the sample is only required to be made into a sheet shape; the calculation method is quick, can be integrated, has low application environment requirement, and can test a wide variety of samples.

In the above embodiment, when manufacturing donkey-hide gelatin powder, selecting block donkey-hide gelatin, manufacturing powder particles smaller than 100 meshes in a clean and closed environment, and accurately calculating the water loss before and after pulverization to be mg; when the terahertz dielectric spectrum of the pressed donkey-hide gelatin is tested, donkey-hide gelatin pressed samples are fixedly placed in holes with two different diameters, terahertz signals only penetrate through the donkey-hide gelatin pressed pieces, the donkey-hide gelatin pressed pieces are wrapped by polyethylene films during testing, moisture in the donkey-hide gelatin is prevented from evaporating during testing, the refractive index of the material is tested by the terahertz time-domain pulse technology, and the dielectric constant of the material is obtained through a dielectric constant formula. When the water content of the donkey-hide gelatin is calculated, the donkey-hide gelatin is divided into two parts, namely free water and donkey-hide gelatin, the dielectric constant of the donkey-hide gelatin is contributed by the two parts, namely the water and the donkey-hide gelatin, and the water content of the donkey-hide gelatin is calculated by utilizing a multivariate linear regression algorithm on dielectric constant test values under different frequency points by utilizing a donkey-hide gelatin binary effective medium model.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure, and various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Although the present disclosure has been described with reference to the specific embodiments shown in the drawings, it is not intended to limit the scope of the present disclosure, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive faculty based on the technical solutions disclosed in the present disclosure.