Ti-Ti3Al metal composite prepared by in-situ synthesis is a good method to improve the properties of titanium matrix composites. In this paper, the influence of Al content on the microstructure and mechanical properties of in-situ synthesis Ti-Ti3Al metal composite produced by selective laser melting （SLM） was studied. The forming test of Ti-AlSi10Mg composite powder with different mixing ratios was carried out by SLM technology and in-situ synthesis technology, and the phase, microstructure, microhardness, wear performance, tensile and compression properties were analyzed. The results show that Al enters into Ti crystal during the forming process, forming Ti-Al substitution solid solution, which strengthens the solid solution of the sample and precipitates Ti3Al particle reinforced phases. With the increase of Al content, the mechanical properties of the sample gradually improved. The microhardness was significantly increased. When Al mass fraction was 10%, the hardness increased to 538.56 HV, reaching more than twice that of pure titanium (220.59 HV). The wear performance increases and the average friction coefficient of the sample decreases gradually. The maximum compressive strength reaches 1 653.9 MPa, which is 164.48% higher than the pure titanium sample, and better than the pure titanium plate after annealing (400-450 MPa) and the TC4 alloy formed by SLM (1 128 MPa). The tensile strength firstly increased and then decreased with the increase of Al, but it was still higher than the pure titanium sample. The combination of in-situ synthesis and SLM technology is of great significance to improve the properties of composite materials.

Laser cladding technology was used to prepare WC/Ni cladding layer on the surface of cold work die steel (Cr12MoV), and the changes of its composition and red hardness were studied. The microhardness tester and ring block friction and wear testing machine were used to test the red hardness and wear resistance of the cladding layer. The results show that when the laser power is 1.0 kW, the powder feeding voltage is 8 V, and the scanning speed is 2 mm/s, the cladding layer is mainly composed of cladding layer mainly composed of γ-Ni (Fe), W2C, Cr7C3, Fe6C2, Fe6W6C, WC, Fe2B, etc. phase and M23C6 eutectic compound composition; when the red hardness test temperature is 200 ℃, the hardness of the cladding layer can reach 57 HRC or more, higher than the substrate 52.1 HRC, when the temperature reaches 400 ℃, the hardness of the cladding layer still reaches 47 HRC or more, and the substrate only has 33.1 HRC; the weight loss of the cladding layer reaches a maximum of 1.7 mg at a red hardness test temperature of 400 ℃ but is still less than the weight loss of the substrate at ordinaryl temperature of 1.9 mg; the red hardness test within 500 ℃ only affects the microstructure of the cladding layer; the degree of chemical conversion has no great influence on the strengthening mechanism and composition of the cladding layer; the cladding layer belongs to the abrasive mechanism within 300 ℃, and evolves into adhesive wear when the temperature reaches above 400 ℃.

In laser metal deposition, fixed process parameters are usually used during the deposition, which easily leads to heat accumulation. In order to reduce the oxidation of titanium alloys caused by heat accumulation during the deposition, a closed-loop control system of molten pool temperature with variable laser power between layers is proposed. For the deposition of TC4 titanium alloy, a PI-controller is designed to control the actual temperature of the molten pool with laser power as input variable. The experimental results indicate that the actual temperature of the molten pool can reach the expected value using PI-controller. The surface of the deposited part is bright silvery white without oxidation. Compared with the deposited part with fixed laser power, the closed-loop controlled deposition block has smaller β columnar crystal and more uniform width, and the microhardness does not increase at the top position. This system provides a new method to control the temperature of the molten pool and provides technical support for the continuous deposition of titanium alloy in an open environment.

In order to better study the application of pulse laser cleaning technology on 316L metal surface of reduction furnace, and improve the decontamination effect and corrosion resistance of metal surface, in this paper, based on the main working environment of polysilicon reduction furnace, 316L stainless steel as the base material was studied. SEM, XRD and EDS were used to test the cleaning results.The optimal parameters and surface were selected by two-stage (micro and macro) evaluation, and the electrochemical strong acid corrosion test was carried out.The results show that the surface of 316L stainless steel after laser cleaning is clean and corrosion resistance is improved, which provides a certain reference for cleaning and application of the inner wall surface of reduction furnace.

With the carbon fiber reinforced resin matrix composite (CFRP) as the processing object, the thermal damage inhibition experiment was carried out around the improvement of 1 064 nm picosecond laser processing mode and the adjustment of process parameters. The results show that the cutting quality along the fiber direction is better than that in the vertical direction, and the anisotropy of the material determines that the heat mainly transfers along the fiber direction and diffuses to the inside of the material. The composite cutting method of moving platform combined with galvanometer is better than the traditional method, and is suitable for thick material processing. The degree of thermal damage is closely related to laser power, cutting speed, scanning radius and filling distance, which is determined by pulse energy density and pulse dispersion. In addition, cutting quality can be further improved by properly increasing cutting times after cutting through materials. After the process optimization, the cutting quality of 2.1 mm thick sample is excellent by composite method, and excellent cutting quality was obtained. There were no defects such as attachments, cracks and pores on the surface of the slit, and the width of the heat affected zone in the material was less than 10 μm.

Compared with traditional welding technology, laser powder-filled welding technology has incomparable advantages to realize flexible welding with large allowance and high quality. Based on the process test of GH3030 superalloy, the effects of laser power, scanning speed and defocusing amount on the weld surface morphology and tensile strength were studied. Under the conditions of laser power 2 100 W, scanning speed 900 mm/min and defocusing amount + 2 mm, the welding seam with certain melting width, even continuity and no defects can be obtained, and the tensile strength after welding is better than that of base metal under the better process parameters. The selection of process parameters has a great influence on the tensile strength of welded joints. On the premise of good metallurgical bonding, the key to improve the tensile strength is to avoid coarse grain and loose structure.

In this paper, the process of pulse laser welding is used for the tantalum sheet with a thickness of 0.5 mm.The influence of laser welding parameters on weld depth and weld width of butt joint is analyzed by orthogonal test. The results show that the depth and width increase with the increase of laser power,and the increase of melting depth is higher than that of melting width. When the power reaches 1 100 W, the weld is completely penetrated. With the increase of welding speed, the weld penetration depth decreases correspondingly. When the welding speed is greater than 8 mm/s, the rate of penetration depth decrease increases obviously. It shows that pulse width and frequency are important factors affecting welding quality. The tensile test results show that the fracture site is in the heat-affected area and the tensile strength of the joint is as same as that of the base metal. The joint has good plasticity and the welding quality meets the technological requirements. The optimal welding process parameters are power 1 200 W, defocusing capacity 0, gun tilt Angle 15°, pulse width 25 ms, frequency 20 Hz, the welding method is pulse welding, shielding gas argon, gas flow rate 10 L/min.

Cu/Al dissimilar metal welding is widely used in energy, electronics, chemical industry and other industries because of its economic and technical advantages in reducing weight and saving resources. However, due to the significant differences in the chemical composition and physical properties of the base metal, brittle intermetallic compounds are easy to form in the welding process, resulting in cracks and other defects, which will reduce the mechanical properties of Cu/Al welded joints. In recent years, laser welding has been applied to Cu/Al dissimilar metal welding because of its unique advantages, which has attracted extensive attention of scholars at home and abroad. In this paper, the research progress of laser welding of Cu/Al dissimilar metals, such as microstructure and mechanical properties, power modulation to improve the quality of Cu/Al welding joint, filler to improve the performance of Cu/Al welding joint and the stability of Cu/Al laser welding, is reviewed, and the future development direction of laser welding dissimilar metals is predicted.

For welding of TC4 titanium alloy of fuel cell,the single-mode fiber laser were used for the experiment.Three factor and three level orthogonal testing of laser power,welding speed and focal distances was carried.Appearance and shear strength were tested.The best process parameters was that laser power was 100 W,welding speed was 60 mm/s and focal distances was 3 mm.Shear strength of welds reached to the highest of 588 MPa and no breakdown caused on the lower layer material.Under conditions of the best process parameters,closed welding track was taked, and air tightness and corrosive of welds was tested. Corrosive testing was carried out in condition of acidic to test discoloration on the surface of welds.Testing result showed that gas tightness and corrosive of welds met the demand of fuel cell,and achieved actual production conditions.

A strip of step-like base metal was reserved and served as filler metal in dual beam laser fillet welding of T-shape joint of 1.2 mm thick TC4 titanium alloy. First of all, step size was optimized. Then, dual beam laser process parameters were optimized under the optimized step size, based on the results of optical microscope observation, scanning electron microscope observation, tensile test and microhardness test of samples achieved under different laser power, welding speed and defocusing distance. The results showed that when the step size was 0.8 mm×0.8 mm, the surface of welding seam was flat and smooth, and there was no sag or bulge. The increase of laser power or the decrease of welding speed increased weld depth and bonding surface. Satisfactory weld shape with a balance between weld depth and bonding surface area can only be obtained when the welding speed and laser power were reasonably matched. The microhardness test results showed that the microhardness of the heat affected zone and the weld were both higher than that of the base material.When the weld depth is moderate, the axial tensile strength of the T-joint was effectively enhanced, reaching more than 90% that of the base metal. The research results are of great significance to reduce the body weight and promote the integrated technology innovation of aircraft assembly in China.

Laser deep penetration welding (LDW) was used to weld T2 copper and SUS304 stainless steel. The effect of beam offset controlled by PLC on Microstructure and tensile properties of welded joint was studied. The results show that the profile morphology of T2 copper-SUS304 stainless steel welded joints with different beam offsets are straight on the copper side and hourglass on the steel side; the weld seam is narrower when the beam offset is positive and wider when the beam offset is negative. The results show that the width of the heat affected zone on the copper side is significantly larger than that on the steel side when the beam is positive offset (the beam is biased to the steel side), and the cellular dendrites near the fusion line are smaller and there are more granular Cu2O phases near the fusion line. When the beam is negatively offset, there are slender columnar crystals growing perpendicular to the weld seam and reticular cells near the weld center, and granular Cu2O can be seen locally Phase. The fracture position of welded joint with beam offset of 0 mm and +0.15 mm is at the weld joint, and the fracture position of welded joint with beam offset of +0.30 mm, -0.15 mm and -0.30 is in the heat affected zone of copper side. When the beam offset is + 0.30 mm, better welding effect can be obtained. The observation results of tensile fracture morphology of welded joint are consistent with the tensile test results.

Laser lap welding was conducted on steel/aluminum dissimilar metals in the experiment. The effects of rare earth addition layer on the microstructure, element distribution, precipitated phases and mechanical properties of interface transition zone were carefully studied. The results showed that the welded joints with good macro/micro shape can be obtained under laser power of 2.0 kW, welding speed of 3 m/min and defocusing amount of +2 mm. The study also found that the addition of rare earth Y in the layer can effectively regulate the metallurgical reaction of steel/aluminum interface and promote the formation of various ductile intermetallic compounds such as Fe23Y6 and Al3Y. To a certain extent, the precipitation of ductile phases at interface can inhibit the generation of brittle phases and effectively improve the mechanical properties of the joints.

1.6 mm DP590 and 2.0 mm DP780 were welded by laser tailor welding under different welding speeds and different laser power, the macro-morphology, microstructure, tensile properties, hole expanding rate and cupping value of the welded joints were tested, analyzed the influence of welding speed on microstructure and tensile properties, revealed the forming performance of welding joints. The result indicate that, the laser welding joints were well formed, the microstructure of weld zone was columnar martensite, the microstructure in the heat-affected zone were composed of martensite and ferrite, and the morphology of microstructure between weld zone and heat-affected zone were slightly different; the welding speed had no obvious effect on the microstructure, yield strength and tensile strength of the joints, increased the welding speed gradually, the elongation of welded joints showed an upward trend; the cupping value and hole expanding rate of laser welded plate were lower than that of two side base metal, but the base material of both sides were vulnerable spot in the forming process. When the laser power was 3.72 kW, the welding speed was 5.5 m/min, the joints shower the best tensile properties and forming performance.

In order to improve the residual stress and torsional deformation of parts fabricated by addition and subtraction hybrid manufacturing, and to enhance the machining accuracy and surface quality of parts, a simulation method based on Simufact Welding（SW） finite element software was developed. This paper used SW software to simulate the effect of laser power, scanning speed, and spot diameter on the distribution of residual stress in the laser additive process. The distribution of residual stress on the inner and outer surfaces of parts was measured using an X-ray stress tester. The experimental data were plotted using MATLAB. Distribution law was found by the residual stress three-dimensional contour plot, which reflected to a certain extent the root cause of the deformation of parts fabricated by addition and subtraction hybrid manufacturing. Using the same process parameters, the residual stress simulation results agreed well with the experimentally measured residual stresses, with an error of 10%.

We have studied the frequency doubling and triple doubling of high-power and high-repetition frequency picosecond lasers. We selected a 1 030 nm Yb-doped fiber laser with a power of 50 W, a repetition frequency of 50 MHz, and a pulse width of 10 ps as the pump source. LBO crystal is used as frequency doubling crystal, the length of the crystal is 20 mm and the beam spot radius is 0.03 mm when the class Ⅰ angle phase matching is obtained through simulation, and the frequency doubling conversion efficiency is 28.08%; the temperature phase matching of the class I is obtained, the crystal length is 20 mm and the spot radius It is 0.039 mm, and the frequency-doubled conversion efficiency is 76.4%. LBO crystal is selected as the triple frequency crystal, and the relationship between triple frequency efficiency and crystal length and spot radius is explored through the type II angle phase matching method. Finally, the energy ratio of the fundamental frequency light to the frequency doubled light is 2∶3, and the crystal length is 20 mm. The spot radius is 0.05mm, and the theoretical conversion efficiency is 18.67%.

Machine vision inspection is a popular detection method at present. Aiming at the problem of large number of assembly line production workpieces and low detection accuracy, a calibration method based on line structured light is adopted to realize batch detection of workpiece hole size and position information. The process includes a camera calibration method, the Hessian matrix line extracts the center line of the laser line, the laser plane fitting calibration, and the point cloud reconstruction of the passenger car pedal. Experiments show that the detection method of the camera system can measure the diameter of the hole in the range of 500mm, and the accuracy can reach 0.3 mm. It can meet the measurement requirements of the dimensional accuracy and position accuracy of the hole on the industrial site.

To meet the needs of secure communications, a scheme of chaotic synchronization based on the two unidirectionally coupled semiconductor ring lasers (SRL) is proposed. The wave form, power spectrum and self (cross) correlation diagrams under several parameters are obtained by numerical simulation, and the effect of injection parameters on chaotic synchronization performance is studied. The results show that the time-delay signatures (TDS) of chaotic signals are obvious when the master SRL is subjected to the optical cross-feedback, which is not conducive to the secure communication system. After introducing optical self-feedback in the master SRL, the TDS is well suppressed, and the quality of chaotic signals is significantly improved. The chaotic signal with low TDS is injected into the slave laser to achieve chaos synchronization. Under the fixed frequency detuning, it is found that the synchronization coefficient can be significantly increased by increasing the injection coefficient. In addition, by drawing a two-dimensional space map, the high-quality chaotic synchronization region with a synchronization coefficient above 0.9 can be determined.

The geometric characteristic parameters of the weld pool can reflect the welding quality in the laser welding process. Laser welding vision system can obtain the geometric parameters of molten pool in real time, which is very important for welding quality monitoring and welding automation. In this paper, the visual system of high-power fiber laser deep penetration welding process detection is improved. The image processing algorithm is systematically analyzed, and the edge of molten pool image is effectively extracted to avoid large interference, and realize accurate on-line measurement of weld pool geometric characteristic parameters. A method of closed convex active contour model based on prior information of molten pool is proposed. It can not only realize the accurate on-line measurement of the geometric characteristic parameters of molten pool, but also has better flexibility and adaptability. Compared with the balloon model algorithm, the measurement error of the closed convex active contour model is stable, the maximum error is less than 13.15%, and the balloon model measurement error is higher than 132.92%, and the error is very large. This method has a good effect of removing interference, and the algorithm is fast and can accurately monitor the geometric parameters of molten pool on-line.

In this paper, the three-dimensional measurement system of laser composite forming is designed, and the dimensional accuracy control of forming parts is studied. The function of the three-dimensional measurement system and its role in laser composite forming technology are analyzed. The mechanical structure part of the 3D measurement system is designed, including two-dimensional motion platform and high-speed profilometer bracket. The designed 3D measurement system can measure the surface topography characteristics and surface data of cladding parts; through matlab processing, the milling frequency is 30.05 Hz, the milling speed is 3.02 mm/s, the power is 102 W, the pulse width is 1.05 ms, and the defocusing amount is 0 mm. The convex points and high points of the cladding parts are processed by the data visualization software, and the images of the cladding parts with the same size and can be used by the laser milling software are obtained File. According to the processing pictures, the laser equipment can effectively mill the high and convex areas with an accuracy of 5.01 μ m, which can reduce the slag on the surface and side of the cladding parts, complete the three-dimensional accurate milling of the cladding parts, and realize the closed-loop control of the three-dimensional morphology.

In this study, laser sealing is selected as the sealing method for missile borne high-density T/R module. The energy distribution during laser sealing is described by finite element simulation, and the sealing test of T / R module is carried out. The finite element model of laser sealing of Si Al alloy is established. The stress field and temperature field of laser sealing welding of Si Al alloy are obtained by numerical calculation. Pulse laser welding can effectively control the welding line energy. There is a small welding stress in the welding center. The welding thermal stress of high silicon aluminum alloy packaging box increases obviously with the increase of the distance from the weld center. The highest welding stress of the shell appears at the side of the shell near the weld, and the maximum thermal stress is lower than the yield strength of the shell material. The welding parameters of laser seal welding are optimized. The welding peak power is 2.51 kW. The increase of pulse width has no obvious effect on improving air tightness. When the peak power is 2.51 kW, the requirement of air tightness of 2.14×10-8 Pa·m3/s can be met.

The microstructure and tensile properties in the conditions of room-temperature and high-temperature, and the reasons of fracture morphology and porosity formation in high temperature tensile fracture about TC4 titanium alloy formend by selective laser melting have been investigated. The results show that the room temperature tensile properties of the TC4 alloy without heat treatment characterized by high strength and low shaping. After the 800 ℃,4h vacuum annealing, the properties of TC4 alloy reached the level of forging pieces of the same brand. Under the tensile conditions at 400 ℃,500 ℃,600 ℃, strength of the deposited samples is higher than that of annealed samples on average of 24.7%,27.9%,8.3%. But the elongation of the deposited samples is lower, excepting the average elongation achieved 45.5% under 600 ℃ for the deposited samples, which has been nearly twice comparing with the annealed sample. Numerous densely distributed pores existed at the fracture place about annealed samples employing by high-temperature tensile. The pores were first formed at grain boundaries, and then in the process of high temperature tensile deformation, due to the necking deformation of the sample, the pores accumulated to the fracture site along with the deformation.

In order to control the weld reinforcement for guaranteeing roller life and increasing rolling quality during continuous cold rolling, the effects of welding parameters on top reinforcement (Rt), bottom reinforcement (Rb), and the thickness ratio of total reinforcement to base metal (Rp) of laser-arc hybrid weld was studied in terms of response surface method. It was found that Rb depends on the laser power and welding speed, while Rt and Rp are determined by welding speed and wire feeding rate. The quadratic regression models of Rt, Rb and Rp were established by the least square method, the fitting degrees of which are 0.928, 0.893 and 0.965, respectively. 5 parameter groups were selected and carried out to verify the models. The experimental data of weld reinforcement well agreed with the predicted results, demonstrating the accuracy of the models. The welding parameters were obtained according to the multi-objective optimization on the basis of welding speed, Rt, Rb, etc., which is significant for parameter selection in industrial applications.

In order to study the influence of process parameters by multi-mode semiconductor laser additive manufacturing on the residual stress field of the cladding layer, ANSYS software was used to build a single-track cladding layer model. The multi-mode semiconductor laser heat source was loaded by using the life-and-death element method. Orthogonal experiment was used to study the influence of process parameters on the stress field distribution in the width and height of the cladding layer. The results show that the stress field along the width of the clad layer is symmetrical on both sides and has obvious platform effect at the center, which reflects the heat of multi-mode laser is average; In the height direction of the cladding layer, the stress increases gradually along the height until the surface of the cladding layer reaches the maximum value; The effect order of process parameters on residual stress is: powder feeding rate> scanning speed> laser power; The maximum stress on the width and height direction of the clad layer is 196.53 MPa and 98.22 MPa when the optimal process parameters are adopted, which greatly reduces the value of residual stress and provides a reference for controlling residual stress in cladding layer by multi-mode semi-conductor laser additive manufacturing.

Based on the laser cooling technology, the effects of laser parameters on permanent magnet Zeeman slower for ytterbium atoms are studied theoretically. The optimal length of the permanent magnet Zeeman slower is obtained by calculating and analyzing the intensity of the cooling laser and the effective coefficient. We show the dependence of the magnetic field distribution of the permanent magnet Zeeman slower on the laser polarization and detuning. The magnetic field amplitude of permanent magnet Zeeman slower can be smller when the capture speed is 310 m/s and σ- light with -400 MHz detuning frequency is adopted, where atoms are more likely to escape from the resonance deceleration process at the end of the Zeeman slower. According to the optimal laser parameters and the magnetic dipole model, we propose a transverse-field permanent magnet Zeeman slower suitable for cold ytterbium atomic optical lattice clocks, which lays the foundation for the development of space-borne clocks and transportable optical clocks.

The 304 stainless steel with a thickness of 1.5 mm is drilled in femtosecond laser (235 fs, 100 kHz) under different defocusing amounts. The drilling rates were recorded. The diameter and taper of micro-holes under different defocusing amounts were measured and calculated. Also, the quality and element distribution of micro-hole sidewall were characterized by optical microscopy and SEM. Experimental results demonstrate that when the defocusing amount deviates from -1.0 mm to 1.0 mm, inlet and outlet diameter of the micro-holes increase, but taper of the micro-holes decreases first and then increases, and the largest taper is 3.32° . Meanwhile, the outlet quality of micro-holes becomes worse gradually. No recast layer or micro-cracks is observed on the sidewall of all micro-holes, while the quality of micro-holes sidewall under negative defocusing amount is better. The element distribution of base metal nearby the sidewall of micro-hole is almost not variable. Compared to positive defocus, the drilling efficiency under negative defocusing amount is higher , and it is about 27 s.

The mechanical lidar based on time-of-flight principle uses the average value of short-time sequence multi pulse measurement as the target distance value, which will causes some virtual points in the point cloud data between targets. In order to filter the virtual point, the relationship between the depth of the virtual point and the distance between the adjacent points is analyzed, and the lightweight recognition formula of the virtual point is proposed. The experiment is completed on the SICK tim561 lidar. Experimental results show that the proposed method can effectively remove virtual points and improve the quality of point cloud.

A high-speed lidar is designed for real-time imaging. This lidar system consists of collimated laser diode,One-dimension MEMS microscanner,Reflector, driving motor and photodetector,in which MEMS is the core device. The MEMS lidar system owns characteristics of high accuracy,low price,high-speed,three dimension and real time imaging.

An optical device is proposed to collect the thermal radiation generated by laser cutting in this paper. The device can be added into the optical path of laser cutting without affecting the normal transmission of the laser. At the same time, it can monitor the laser penetration and cutting process. First of all, ZEMAX is used to design the optical path. Through a special mirror, the thermal radiation is reflected from the laser light path to the outside, and finally enters a sensor well. Then, the optical device of collecting thermal radiation is added into the laser cutting head by using a 3D software. Finally, the results are show by using the TRACEPRO. The software can be used to observe the thermal radiation light collected by the sensor when the cutting head is working. From the actual test curve of the output, the optical device can clearly judge the laser penetration time point and the abnormal situation during cutting, which shows that the design method is feasible. The device can be used to improve the cutting quality and protect the expensive laser.

Laser driving circuit is an important part of lidar, and its technical specifications will directly affect the overall performance of lidar. According to the characteristics of laser, the laser pulse has two main parameters: pulse width and energy. These two factors have a large effect on the distance resolution and the range respectively. Most of the common driving circuits use DC-DC boost circuit, large inductor charge and discharge to achieve, the energy is unstable, and the circuit ripple is large. In the past decade, cost-effective Si MOSFET devices have been highly commercialized. However, the parasitic inductance and switching quality factor will significantly affect the laser driving circuit. When the pulse width is narrow to a certain extent, the peak power of laser pulse will drop sharply. In order to solve the above problems, this paper designs a laser drive circuit, which realizes a drive circuit with narrow pulse width, small size, low power consumption, low noise, and strong high voltage stability, and points out what should be paid attention to when designing the drive circuit. The output of the laser can be directly controlled by the CPU, to achieve high repetition frequency, The output rising edge is about 2ns and a pulse width of 10ns, The size of the circuit board is about 3.2 cm×2.8 cm, and the power consumption of the single board is about 0.5 w, these characteristics can be used in the engineering of lidar.

Starting from the design principle of quasi-continuous fiber laser power supply, this article analyzes the power demand of quasi-continuous fiber lasers. According to energy conservation, by controlling the change of energy storage capacitor energy, a laser diode power supply driving solution is proposed and analyzed. First Boost boosted and Buck constant current secondary circuit topology, developed a high power density, high efficiency, low ripple quasi-continuous fiber laser power supply system, through experiments and batch production verification of the whole machine shows that the power supply The system satisfies the stability and reliability of instantaneous high-current output, and realizes the precise and controllable output laser energy, which has practical reference and reference significance for the subsequent development and application of high-power QCW lasers.

Application of tunable diode absorption spectruscopy(TDLAS) to power plant FG tail duct or extraction measurement could reflect the combustion condition to some extent. But it is not a direct and rapid method. To support the diagnose the combustion process more directly, this present paper designed a combust TDLAS sensor to measure the coal-fired power plant using a pair of H2O transitions near 1.3 μm. The temperature was measured during the whole starting process of the power plant, which is a support for developping non-intrusive in-situ measurement system and combustion controll.

To observe and to analyze the clinical efficacy of Percutaneous Lasers Disk DeoomPression(PLDD) combined with Spinal Balancing Manipulation and Duzhong Yaotong Pill in the treatment of Lumbar disc herniation (LDH); From Mar. 2012 to Mar. 2015,the cases in the spinal surgery of Gansu Provincial Hospital of TCM to accept PLDD combined with Spinal Balancing Manipulation and Duzhong Yaotong Pill were followed up statistics,and according to the combination of different treatments were categorized groups. The VAS scores at different time points and the clinical efficacy after 1 years were recorded and evaluated, and the effectiveness of each treatment method was analyzed. Results: the VAS scores of PLDD combined with different treatments for LDH was not statistical significance within 6 months after treatment (P>0.05),while the VAS scores of group C was remarkably different from that of group A and B at 6months and 12months after treatment (P<0.05); the therapeutic evaluationtion of the each group showed that the effective rate of group A,B,and C was not statistical significance in 12 months after treatment,The excellent rate of group C was reached 83.8%, which was apparently higher than that of group A and B. Conclusion: The use of PLDD combined with Spinal Balancing Manipulation and Duzhong Yaotong Pill is effective in treating LDH and has good application value．