Selective laser melting (SLM) is a technique in which the powder is melted with laser scanning and solidifies, and the parts are directly fabricated layer by layer. Based on the optimization of process parameters, the single-layer sintering experiment of Ti6Al4V powder was conducted and the guiding range of linear energy density for selective laser melting of Ti6Al4V powder was obtained; on this basis, multi-layer sintering was carried out and the comprehensive analysis was made in combination with metallographic, mechanical properties test and the internal structure of the sample obtained by SEM image. The results indicated that the sample has better mechanical properties when the linear energy density is 0.35–0.55 J/mm: the bending strength is 1 111–1 179 MPa and the hardness is 220–305 HBW. Finally, three-dimensional forming sintering was realized under the optimized process parameters.

In this paper, laser-MIG hybrid heat source is used to conduct welding experiments on 6.9 mm thick plates of 5A06 aluminum alloy. The paper analyzes the weld macroscopic morphology with different welding parameters. The change trend of weld microstructure with temperature gradient is studied, and the reason for the change in microhardness is explained. The research results illustrated that the four welding parameters adopted in this experiment achieve good weld formation, while defects such as lack of penetration, undercut do not exist in the welds. The depth to width ratio of four welding parameters are all above 1.5, Case 4 can achieve 2.04. In addition, with the decrease of the welding line energy, the cooling speed of the weld joint is accelerated and the strengthening phases such as Mg2Al3 in the weld is increased. It resultes in the increase of microhardness of the weld along the direction perpendicular to the weld centerline.

The current forming quality and mechanical properties of the additively manufactured Inconel 718 alloy are difficult to control. Inconel 718 deposition layer was fabricated on the surface of H11 steel via the technology of laser directed energy deposition to investigate the effect of process parameters on the characteristics and microhardness of the deposition layer. The effects of laser power, scanning speed and powder feeding rate on the geometrical morphology, aspect ratio, dilution rate and microhardness of deposition layer were studied by means of orthogonal experimental. The process parameters were optimized with the aim of aspect ratio, dilution rate and microhardness. The final optimized process parameters were laser power 1 800 W, scanning speed 10 mm/s, powder feeding rate 19.71 g/min. Better quality deposition layer can be obtained by applying optimized process parameters.

The process of laser cutting 20 mm thick Q345 carbon steel with high power fiber laser was used to investigate and observe the microstructure of the recast layer and heat affected zone after cutting. The effects of laser power, cutting speed, auxiliary gas pressure, and defocus amount on cutting quality were compared using multiple sets of single-factor experiments. The optimal process parameters in this study were laser power 8 kW, cutting speed 0.6 m/min, Defocus amount +10 mm, oxygen assist pressure 140 kPa, nozzle diameter 1.4 mm, cutting height 0.5 mm. The morphology of the cross-section of the cut carbon steel samples was observed by SEM. The differences in microstructure and size between the recast layer and the heat affected zone and the substrate were found. The formation mechanism of the microstructure in the recast layer and the heat affected zone was analyzed. This research is helpful for the promotion of the application of ultra-high power fiber laser cutting technology in the field of cutting medium and thick steel plates.

Elliptical micro-pit array was fabricated on the plane section of boron cast iron cylinder liner with nanosecond pulse laser. The influence of filling processing method and parameters on surface morphology of elliptical micro-pits was studied. The results show that the ring filling has better surface morphology than other three processing methods. The maximum depth and the maximum area of the micro-pit length-diameter section increased as the filling line width decreased, and the maximum depth reached 218 μm. When the filling line width is greater than or equal to 3 μm, the molten material at the bottom of the micro pit decreases obviously. The influence of scanning speed on the morphology of micro-pits was related to the filling line width. When the filling line width was small, maximum depth and the maximum area tended to increase and then decrease with scanning speed increased, the inflection point is 400 mm/s. When the filling line width was large, maximum depth and the maximum area were inversely proportional to scanning speed. Laser frequency has limited influence on maximum depth and the maximum area. The maximum area change rate is only 5.61%, which mainly shows that the bottom of the micro pit tends to be more gentle with the increase of frequency.

Three different samples of Ti6Al4V, GH3536 and 316L stainless steel were prepared by laser selective melting process. The microstructure evolution and mechanical properties were studied by means of optical microscope (OM), scanning electron microscope (SEM), universal tensile testing machine and Vickers hardness tester. The results show that a large amount of needle-shaped marten site α′ phase is distributed inside Ti6Al4V, which is decomposed into α+β phase during the forming process to form a net basket structure. GH3536 has a strip shape in cross section and a fish scale shape in longitudinal section. Equiaxed crystals are distributed in 316L stainless steel. The average elongations of 316L stainless steel and GH3536 are 34.17% and 36.75%, respectively, which are 23.69% and 26.27% higher than that of Ti6Al4V. The tensile strength and yield strength of Ti6Al4V are 1 122.83 MPa and 853.17 MPa, which are better than GH3536 and 316L stainless steel. The tensile strength is increased by 51.63% and 74.81%, and the yield strength is increased by 159.85% and 54.37% respectively. The strength of the sample is higher than the national standard strength level of common forging, reaching the industrial use requirements, the comprehensive performance is better than the traditional manufacturing process, and the sample has better strong plastic matching under laser selective melting.

Based on the theory of photoacoustic (PTA) effect of solids, a theoretical model of PTA effect for multilayered graphene film was established, and the sound pressure expression of the PTA signal from a multilayered graphene film was derived. After performing theoretical calculations and experimental tests on PTA effect of the graphene films of different substrates under ultrafast pulsed lasers, it shows that theoretical values basically coincide with test results in the frequency domain, which effectively validates the theoretical model. Furthermore, the sensitivity analysis method was used to analyze the relevant factors that affect the photoacoustic efficiency of the graphene film. The analysis indicates that the thickness (5-15 nm) of graphene lms plays a trivial role in efciency, and the sensitivity coefcient is less than 0.01. The substrate thermal effusively has signicant effects on efciency, with the sensitivity coefcient around 1.88; substrates with lower thermal effusivity exhibit better acoustic performances. The sensitivity coefficients of ambient gas density, thermal conductivity and specific heat are 1.09, 0.97, and 0.9, respectively. The sound pressure level generated by graphene films is approximately proportional to the inverse of specific heat. This research is of instructive importance to the application of graphene films in PTA loudspeakers and other related fields.

In this study, the Al-12Si alloys were prepared by the ultrasonic-assisted laser metal deposition method. The effect of laser power, scanning speed, scanning spacing and ultrasonic power on the density of the deposited layer was investigated. The microstructure and mechanical properties were analyzed using metallographic microscope, scanning electron microscope, electron backscatter diffraction technology and tensile test. The results show that the density of deposited samples increases with the enhance of laser power and ultrasonic power, and first improves and then reduces with the increase of scanning speed and scanning spacing. When the process parameters of laser power 1 100 W, scanning speed 6 mm/s, scanning spacing 1.0 mm, and ultrasonic power 1 000 W were used, and the same deposition layer was scanned twice perpendicular to each other, the sample with the highest density of 99.1% could be obtained. At this time, the deposited layer was mainly composed of α-Al solid solution with grain size of 2.5~75 μm and Al-Si eutectic. Due to the improvement of the density, the tensile strength and elongation of the ultrasonic optimal test specimen were 17% and 53% higher than those of the optimal test specimen without ultrasonic vibration.

Metallic film coated composite materials, which are with heat-resistance, anti-radiation and low rate of expansion properties, are one of the base materials for electro-magnetic wave transportation controlling when applied to aeronautical, astronautical and signal delivery fields. To accurately etch the top metal film pattern without damaging the base composite materials is required. This article systematically studied the effects of key laser parameters with ultrafast laser and their performance on etching results. It is found that aluminum film could be removed with laser parameters of energy density 3.80 J/cm2, pulse overlap 60% and 3 times of overscan by using a 100 kHz, 480 fs and 1 030 nm laser source. These findings will not only contribute to the aluminum-silica fiber structure materials etching but also help to guide similar wave-transparent materials ultrafast laser processing.

Based on the short-wave (532 nm) nanosecond pulse laser, this article explores the influence of several pulse laser processing parameters (such as peak power, single pulse energy, overlap rate, scanning angle) on the molding process of metal 3D printing technology, and preliminarily studies the process method of multi-material coating based on pulse laser. Compared with continuous laser metal 3D printing, this research finds that the shock wave phenomenon of pulse laser can significantly improve the structure morphology of 3D printing parts; It can realize bonding of multiple materials by versus of laser etching the micro-nano structure on the substrate surface.

Shanxi is a large province for the excavation of bronze cultural relics, and also an important area for early bronze casting, but most of the unearthed bronze cultural relics have been severely corroded. Compared with traditional chemical cleaning and mechanical cleaning method, the laser cleaning method has become a supplement and extension due to its advantages such as high energy, short time, no damage to the substrate and environmental protection. Firstly, the laser cleaning technology was used to conduct an experimental study on the surface of copper coin for the contamination of rust, by optimizing the parameters of laser pulse energy, spot size, repetition times and other parameters. The cleaning comparison test was performed on the samples to be cleaned, and the optimal cleaning energy threshold value was set by 105 mJ. Secondly, the high-energy pulsed laser beam generated by a Nd: YAG laser was used to simulate on the surface of the copper coin sample to generate plasma based on Laser-induced breakdown spectroscopy (LIBS). Then the interaction correlation between the specific spectral line intensity of the plasma during the laser cleaning process and the laser cleaning intensity was analyzed and concluded. Therefore, the laser cleaning effect was evaluated by comparing the spectral line characteristics of the plasma. Finally, a clear and auroral texture was obtained while the optimal laser cleaning parameters were selected to clean the copper coin samples. The experimental results show that the laser cleaning method has the advantages of short time, no damage to the base, good effect and so on, and has certain application value in the conservation of bronze relics.

Pure copper and copper alloys are widely recognized and applied in industries due to their good thermal conductivity, electrical conductivity, ductility and other characteristics. Based on the 532 nm nanosecond pulse laser, this thesis initially explore the influence of several pulse laser processing parameters (such as average power, scanning speed, spot size, etc.) on the forming of pure copper and copper alloys, and through optimized processing parameters, this thesis manufactures some pure copper and copper alloy samples by versus of 3D printing to verify the feasibility of 532 nm nanosecond pulse laser.

Laser cladding of different process parameters was carried out on Q235 steel substrate with 316L stainless steel powder. The metallographic observation, hardness measurement and phase identification of the cladding samples were carried out by optical microscope, Vickers hardness tester and X-ray diffractometer, respectively. The residual stress state in the surface of the was measured by means of blind-hole method. The influence of laser power, scanning speed and powder feed rate on the microstructure and performance of the cladding layer were studied. The results show that, in a certain range, the increase of laser power and powder feed rate and the decrease of the scanning speed will induce the coarse grain size, the thicker cladding layer, the lower hardness and the higher residual stress in the cladding layer.

The 3D graphite/ceramic composites prepared by selective laser sintering technology are porous and have poor mechanical properties and thermal conductivity. In this paper, the effects of different composition of mixed powder and different post-treatment process on thermal conductivity and compressive strength of graphite/ceramic composites were studied. The results show that the compressive strength and thermal conductivity of the composites are increased by adding high purity silicon powder to form silicon carbide reinforced phase at high temperature, and the compressive strength and thermal conductivity of the composites are decreased by adding expandable graphite powder due to the increase of closed porosity, but the latter decreases more obviously. The compressive strength and thermal conductivity of 3D graphite/ceramic composites were greatly improved by vacuum pressure impregnation of phenolic resin solution and silica sol solution. Finally, a 3D graphite/ceramic composite mold with compressive strength of 13.04 MPa and thermal conductivity of 1.94 W/(m·K) was prepared, which was successfully used in repeated casting of steel castings. Through the analysis of casting defects and use cost, the prepared graphite/ceramic composite parts are expected to replace the traditional sodium silicate sand mold.

A 10 kW fiber laser was used to conduct the experimental study on laser-arc hybrid welding with 10 mm AH36 marine steel in this paper. Which was also compared with MAG welding on the same material, and was analyzed from aspects of weld molding, weld section morphology, welded joint mechanical properties, welding deformation, efficiency and cost. The results show that MAG welding and laser-arc hybrid welding both can acquire good weld molding and cross-section morphology by selecting the appropriate wire feeding speed, and the weld strength is also greater than the base material. The deformation of laser-arc hybrid welding is only about 50% of MAG on the same thickness and length welds.The welding efficiency advantage of laser-arc hybrid welding is more obvious, which can be 5 times as much as MAG welding. The welding material cost of hybrid welding is only 21% of MAG welding, gas cost is about 42% of MAG welding, the difference of equipment cost is becoming smaller with the same efficiency. In the long run, the advantage of laser-arc hybrid welding is much greater than MAG welding.

The MOPA nanosecond pulse laser was used to weld 316 stainless steel, and the influence of pulse width, frequency and welding speed on weld formation was explored, as well as the mechanism. It was found that a smooth weld seam without porosity defectcould be easily acquired at high laser pulse frequency, which played a key role in welding thin sheets. At the range of 30-120 ns pulse, the weld depth increased with pulse frequency to the maximum at central pulse frequency, and then decreased. While for the longer 200-500 ns pulse, the weld depth decreased as the pulse frequency increasing ( >100 kHz). According to the cross-section morphology at the different pulse frequency, there were two different welding regimes: the keyhole (or deep penetration) and conduction regime. It was suitable to welding stainless steel sheets at long pulse and high frequency controlled by conduction mode, resulting in sound weld quality.

In order to avoid damage to the inner surface of the cavity-containing parts and improve processing efficiency, it is necessary to determine the number of pulses required to penetrate the material during the laser drilling process. The photodiode is used to detect the light signal on the upper surface of the material during the laser percussion drilling processof GH3536 superalloy. And the acquired voltage signal is used to judge whether the material has been penetrated, then the number of pulses that have been applied when the material is penetratedcan be recognized. The results denote that the change of the voltage signal amplitude generated by the selected photodiode can reflect the change of the laser reflected light intensity on the upper surface of the material caused by the change of the hole morphology during the drilling process, thereby the drilling process can be divided into 3 stages, and it is successfully identified that the number of penetration pulses under the test parameters is 14.

Due to high hardness and corrosion resistance, the Mo2NiB2 ternary boride could be used in the surface protection engineering of Q235 steel. In this work, Mo, Ni, B powders were used as raw materials to in-situ fabricate the Mo2NiB2based cermet coatings on Q235 substrate by the laser cladding technology. The influence of laser cladding times on the structure and property of the coatings was investigated. The results showed that the laser-cladded Mo2NiB2coatingwas composed of Mo2NiB2 ceramic hard phase and FeNi alloy bonding phase. With increasing the times of laser cladding, the relative content of Mo2NiB2 ceramic phases firstly increased and then decreased. The Mo2NiB2 ceramic phase tended to aggregate in the middle sites of thecoatings. Besides, a metallurgical bonding zone with a gradient of composition was formed between the cladding Mo2NiB2 coating and the Q235 substrate. As the laser cladding times increased, both the hardness and corrosion resistance of the Mo2NiB2coating were firstly enhanced and then weakened. Especially, the highest hardness and corrosion resistance of the coatings were obtained when the laser cladding by 3 times, which were 1 and 2 orders of magnitude higher than Q235 substrate, respectively. The changes in the properties of the Mo2NiB2coatingswere mainly determined by the microstructure and relative content of the ceramic phase in coatings.

Laser plastic welding could improved the quality of products greatly, so the demand of laser plastics welding would be more and more. There are many process parameters affecting plastic welding, and lots of experiments such as orthogonal experiment were required to test for getting the best process parameters. In this paper, laser transmission welding testing for thermoplastic ABS plastic was carried out. Single factor experiments of laser power, welding speed and focal distances were used to analyze the regular of welding effects. Then power density was used to research shear strength and microcosmic. When power density was less or more than 1.6 W/mm2, the welds was brittle fracture, shear strength was weak. When power density was 1.6 W/mm2, the welds was ductile fracture, and shear strength was reached to the highest of 71 MPa. The analysis results showed that, single factor of laser power density had direct effect on the microcosmic of welds and then effect on the shear strength.

The intelligent manufacturing system based on integration of 5G and industrial internet is designed to meet the requirements of high safety and high reliability, as well as the characteristics of multi-species and small batch production for large aircrafts. The support and promotion of intelligent manufacturing from industrial internet is discussed based on the basic mechanism of combination between industrial internet and intelligent manufacturing. The case study of intelligent manufacturing is presented based on its applications in large aircraft manufacturers.

To explore the process of laser cutting parameters on the temperature field, the influence of carbon fiber composite material with the method of the finite element simulation analysis and test, considering the auxiliary gas cooling and heat radiation effect, the qualitative simulation analysis of the laser power, scanning speed and laser spot radius of carbon fiber composite material thickness direction and perpendicular to the direction of laser scanning the influence law of temperature field, the results show that the laser cutting process parameters on the specimen thickness and vertical cutting direction of thermal effects have consistency. When more energy is absorbed, the gasification region of the matrix is larger than the ablation region. When the laser energy decreases, the ablation region is gradually larger than the gasification region. The relationship between laser cutting process parameters and temperature can guide the actual processing, predict the thermal affected area of carbon fiber composites in advance, and provide basis for laser heat transmission and control of thermal affected area.

The Zr55Cu30Ni5Al10 samples were prepared by 3D printing laser, and their microstructure and mechanical properties were studied. The results show that the relaxation enthalpy and crystallization enthalpy of the supercooled liquid region are greatly affected by the holding time, holding effect and temperature change of the sample. In the process of heat treatment, the higher the sample temperature is, the longer the holding time is. Because of the change of nanocrystals, the value of crystallization enthalpy is lower, and the relaxation enthalpy increases first and then decreases. In the supercooled liquid region, the heat treatment can increase the free volume of the HAZ and the molten pool in the 3D printing laser formed Zr based amorphous, and the hardness and modulus of the samples such as the HAZ and the molten pool will decrease in varying degrees. After heat treatment, the compressibility of 3D printing laser formed Zr based amorphous decreases significantly.

In this essay, take the 5.0 mm thick high strength steel plate as the experimental material, and analyzes the weld shaping, process stability and droplets transfer characteristics of CO2 laser-MAG hybrid welding with different the arc energy. Experimental results show that, when the laser power P=1.6 kW, welding speed v=1.2 m/min, if welding current I<180 A, current voltage U=24 V, or welding current I=180 A, current voltage U<24 V, the transfer mode is short circuit transfer, or globular transfer or transfer mode between short circuit and globular. When welding current I≥180 A, or current voltage U≥24 V. The transfer mode is spray transfer and the weld shaping is more smooth.

To solve the problem that the laser echo is easily polluted by noise and the sample will be lost randomly when there is occlusion, which will affect the extraction of useful information in the echo, a method of laser echo signal enhancement based on the bayesian factor analysis (BFA) model is proposed. Firstly, based on the analysis of the characteristics of the laser echo, the orthogonal factor model is used to model it, so that the problem of signal enhancement can be transformed into the problem of solving the model parameters. Then the variable bayes expectation maximization (VBEM) algorithm is used to update the model parameters adaptively and iteratively, and the laser echo enhancement can be realized under the minimum reconstruction error criterion. Finally, the measured data are utilized to carry out the experiment. In the environment of low SNR and incomplete random missing data, the proposed method can obtain better noise suppression performance and higher missing sample reconstruction performance, so as to ensure that the follow-up signal processing can accurately collect high-value information in the echo.

In this paper, we design a semiconductor nano laser driver for remote control, and test its output characteristics. The constant current drive circuit of semiconductor nano laser includes three modules: slow start module, constant current module and over-current protection module. The constant current mode is used to control the laser to ensure its output constant optical power. The whole circuit is powered by the slow start circuit, which belongs to the current series negative feedback circuit, and the positive input is connected with the sliding rheostat. The core of the temperature control circuit is MAX1 969 chip, whose control accuracy can reach 0.01℃. By testing the laser system, the results show that the laser threshold is about 18.5 mA, when the pump current is 149.5 mA, the output power of the pump laser is 54.8 mW. The laser has good temperature and current stability.

For the optimization of the substrate radius of cosmetic cotton die-cutting tools produced by laser cladding, a single-factor test method was used to study the influence of the cylindrical substrate radius on the morphology and internal quality of cladding layers of the "curvilinear path trajectory on curved substrate". The results demonstate that the morphology and surface roughness of cladding layers are improved by reducing the radius of the cylindrical substrate appropriately. The cladding efficiency decreases as the radius of the cylindrical substrate increases; while the porosity of cladding layers increases with the increase of the radius, a larger radius of the cylindrical substrate produces smaller, more evenly-distributed grains and a higher hardness of cladding layers. with the highest hardness reaching 3.79 times of that of the substrate; as the radius increases to 40 mm, the cross-sectional morphology, cladding efficiency, porosity and microstructure properties become the best. The research results provide a theoretical basis for studies of the quality of laser cladding of “curvilinear path trajectory on curved substrate” for cosmetic cotton die-cutting tools and the like.

Aiming at the problem that the laser cladding process is difficult to accurately control due to the heat input, the molding accuracy and quality are difficult to achieve the expected problem. By building a laser cladding molten pool monitoring system, the size of the molten pool was accurately measured, and the relationship between the cladding parameters and the shape of the molten pool was obtained. Using the color CCD colorimetric temperature measurement method, a pseudo-color temperature map that can display the temperature field distribution is obtained. The results show that the morphology of molten pool changes greatly with the change of laser power. The influence of the change of powder feeding rate on the morphology of molten pool is not obvious. Due to heat accumulation, the “tailing phenomenon” of the molten pool always exists in the entire cladding process of the molten pool, and it will become more obvious with the increase of power. This makes the area of the molten pool measured by the CCD camera fail to accurately reflect the changes in the molten pool during the cladding process. Therefore, in the subsequent design of the laser cladding closed-loop control system, the width information of the cladding pool should be selected as the variable in order to achieve the purpose of high quality cladding.

The frequency-selecting and sensing properties, in plasmonic system composed of waveguide and ring cavity with embedded metal bar, are numerically and theoretically demonstrated. Modulating the location of metal bar introduces the periodic variation of transmission spectra, which provides a new degree of freedom for controlling the resonant modes. In addition, the sensitivity and figure of merit reach 1 627.5 nm/RIU and 37.893 5, respectively. The results provide theoretical basis for the designing ultracompact optical switch, sensor and filter.

Based on machine vision, the image processing and feature extraction of laser welding pool were studied in this paper. The results show that the monitoring results of optical fiber laser deep penetration welding pool are analyzed, including penetration status, weld width deviation tracking monitoring and line monitoring. Under the condition of welding speed and different welding power, the welding monitoring system can realize the real-time monitoring of optical fiber laser deep penetration welding pool, and its accuracy can meet the requirements of laser welding. In the process of deep penetration welding, the change of welding speed has a significant effect on the welding process. The penetration phenomenon can change the heat dissipation condition and cause the difference of the geometrical characteristic quantity of the molten pool. Determine the coefficient of change of weld width in advance, and judge whether there is penetration in the welding process. Track and monitor the distribution range of sub-pixel corner points and the trend of weld pool characteristics, and effectively judge the welding through the phenomenon of weld deviation.

The medical laser has the advantages of small volume, high output power, light weight, good laser stability and easy to use. It has been used in medicine for more than 30 years. In recent 20 years, medical laser has become a powerful tool in urology surgery, more and more used in various fields of urology. With the progress of equipment and technology, medical laser has developed neodymium laser, green laser, holmium laser, thulium laser and other technologies. The characteristics of various laser devices and the new progress of clinical application of various laser technologies are reviewed.

Objective: to observe and analyze the changes of surface electromyography monitoring data after Percutaneous Lasers Disk DeoomPression (PLDD ) treatment of Lumbar disc herniation(LDH) and investigate the correlation between the electromyographic regularity of trunk and the therapeutic efficacy of PLDD. Method: select from Mar. 2015 to Apr. 2016 in 36 cases of LDH patients treated with PLDD in Gansu Provincial Hospital of TCM, and to monitor those patients in the period of intraoperation, postoperative surface electromyography (sEMG) and surface electromyographic biofeedback. The subjects underwent the sEMG monitoring of paraspinal muscles using long contraction state, motorial state and static position state respectively,The mean frequency slopes (MFslope, MFs), the flexion extension ratioratio (FER)and mean electromyogram amplitude were measured in both the epileptic and contralateral sides of paraspinal muscles, and organized the test data for statistical analysis. Results: the attenuation of MFs in the epileptic side of MFs decreased significantly compared with that before treatment (P<0.05) in 1 month,3 months and 6 months after the PLDD, while there was no obvious change in the attenuation of the contralateral side; there was no significant change in mean EMG amplitude of contralateral side after PLDD, and the amplitude of the epileptic side increased, but the difference was not remarkably. the epileptic side FER=0.46±0.13, and FER=0.89±0.19 before treatment, the difference was conspicuous (P<0.05), the attenuation of FER in contralateral side was not striking changed. Conclusion: percutaneous lasers disk deoompression in the treatment of lumbar disc herniation can significantly improve paraspinal muscle fatigue, dysfunction, dysequilibrium and other pathological status, and effectively restore the intensity、equilibrium and coordination of paraspinal muscle; It is of clinical significance for efficacious evaluation of sEMG monitoring and prognosis of the disease after LDH treatment.