A solenoid magnetic field plays an important role in a non-line-of-sight azimuth transmission system based on polarization-maintaining fiber, which is directly related to the transmission accuracy of azimuth information. This research mainly studies the factors that affect the solenoid magnetic field according to the modulation signal from the direct current to the alternating current, as well as the hollow solenoid. First, the magnetic field components of the static solenoid are derived from the Biot–Savart law by using the uniform cylindrical current equivalent model. Then, the magnetic field of the near axial region is studied from the axial and radial directions, and the feasibility of calculating the magnetic field of the multi-layer solenoid with the superposition principle is verified by measuring the magnetic field of each position on the axis of the solenoid with a Gauss meter. Finally, the alternating electromagnetic field model is established using Maxwell’s equations, and the magnetic and electric fields of the hollow solenoid are further solved. The results show that the magnetic field in the middle part of the magneto-optic glass is more stable, and the magnetic collecting ability of the solenoid is stronger. The magnetic field intensity at the center of the magneto-optic modulation solenoid of the system is the largest, and it decreases with the distance from the center. The alternating electromagnetic field is closely related to frequency. The results provide a reference for the study of the azimuth accuracy of a non-line-of-sight azimuth transmission system.

The aim of this work was to employ optimization strategy based on statistical experimental designs to enhance the polysaccharides extraction yield from Gynostemma pentaphyllum. The effects of three independent variables on the polysaccharides extraction yield were investigated and the optimal conditions were evaluated by means of Box-Behnken design. The optimal conditions are as follows: ratio of water to raw material 31, extraction temperature 90℃ and extraction time 2.5h. Under these conditions, the polysaccharides yield is 3.80±0.15%(N=5) , which is agreed closely with the predicted yield value. ExperimentalMaterials and instrument. Dried G. pentaphyllum was purchased from Guang Ming Prepared Medicinal Herbs Factory (Hebei, China). Glucose(C 6 H 12 O 6 ) as standard was purchased from Guoyao Chemical Reagent Co. (Shenyang, China). All other chemicals were of analytical grade. The analysis of gynostemma polysaccharides was carried out on a 722 spectrometry from Shanghai YuLong instrument Co., LTD. Methods. The G. pentaphyllum was extracted with 95% ethanol at 50℃ for 2h for 2 times and then the residues were dried. A 10g dried residues of G. pentaphyllum was extracted in water bath with distilled water in a designed ratio of water to raw material, extraction temperature and extraction time. The supernatant was collected for the determination of polysaccharides yield.

Because of the shortcomings of traditional infrared-polarization image fusion algorithm, such as low intelligence and single optimization index, this paper proposes an intelligent infrared-polarization image fusion optimization algorithm based on fireworks algorithm. Firstly, an improved differential image correction method based on single pixel nonuniformity is proposed to remove the cold reflection. The two-dimensional discrete cosine transform (DCT) is used to reduce the image sensitivity and improve the robustness, and the Stokes vector formula is used to obtain the polarization characteristic image. Secondly, based on the strong complementarity between infrared-intensity image and degree of linear-polarization (DOLP) image and the explosive optimization of fireworks algorithm, the problem model of weighted fusion algorithm is established, and the fitness function based on root mean square error (RMSE) is constructed to calculate the optimal weight of source image. In the fusion experiment of long-wave infrared-intensity image and DOLP image, this method is compared with the common fusion algorithms. The results show that this method can effectively fuse the infrared-intensity and degree of polarization information, and the evaluation indexes of standard deviation, spatial frequency, mutual information, structural similarity, peak signal-to-noise ratio and information entropy of the fusion image are better than the comparison algorithm. In the future, cooperated with the long-wave infrared-polarization imaging system, this method can be applied to improve the infrared detection ability in complex environment.

Focusing on the problem that the polarization aberration caused by the non-normal incidence of the polarized beam affects the accuracy of the azimuth transmission during the fiber coupling process of the non-line-of-sight azimuth transmission system, this paper starts from the principle of non-line-of-sightazimuth transmission. The polarization aberration relation of the lens-fiber combined interface is established based on the Fresnel formulafor the attenuation difference between the horizontal and vertical electric vectors. Further, the azimuth solution model affected by polarization aberration is established. Numerical simulation results show that in non-normal incidence, no polarization aberration will occur when the polarization angle between the incident ray and incident surface is 0° or 90°. Otherwise, the polarization aberration changes toward the incident surface, and the azimuth transmission error will increase with the increase of the polarization aberration. Last, the optimization measures are proposed. This is of great significancefor further improvement of the azimuth transmission system based on polarization-maintaining fibers, the selection of the instrument,and the improvement of the system measurement accuracy.

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