In this paper, microstructured and nanostructured Al2O3-13wt.%TiO2 coatings were prepared on Ti-6Al-4V alloys by plasma spraying and laser remelting. Optical metallographic microscopy (OM), scanning electric microscopy (SEM) and micro-hardness test methods were used to investigate the effects of laser remelting on the microstructure and properties of the coatings. The test results show that the pores and lamella defects of the as-sprayed coatings were eliminated to obtain smooth and dense coatings after laser remelting, and a good metallurgical bonding was formed between the laser-remelted coatings and the substrates. After laser remelting, the average Vickers hardness values of the laser-remelted microstructured and nanostructured Al2O3-13wt.%TiO2 coatings were increased from 803 HV0.3 and 846 HV0.3 to 1 111 HV0.3and 1 451 HV0.3.

In order to study the variation of the microstructure and properties of laser cladding alloy layer under the conditions of high temperature heat treatment .Laser cladding of Ni60 and Ni60+25%WC alloy coating on Q235 steel was achieved by using a continuous fiber lasers named YLS-4000. And made heat treatment on the two cladding samples by 600 ℃ and 10 h insulation by SXL-1030 programmable box furnace. The microstructure and properties of cladding samples was carried out by means of metallographic, SEM, XRD, high-temperature friction and wear equipment and micro-hardness equipment. The results show that Ni60 alloy layer microstructure dense needle-like crystals and dendrites. After high-temperature heat treatment, the crystal grains grow larger granular and the micro-hardness and wear resistance of Ni60 alloy layer slightly decline which exhibits good resistance to high temperature wear resistance; Ni60＋25%WC alloy layer has WC grains. . After high-temperature heat treatment, the WC grains distribute more uniformly which leads to the wear resistance and micro-hardness of Ni60+25%WC alloy layer improve.

The molten pool temperature of laser deposition shaping titanium alloy was measured by using infrared thermometer real-time tracking measurement method, the effect of process parameters and scanning path on both molten pool temperature and layer size during metal laser deposition forming was researched. The results show that, with the laser power and powder feeding rate increasing, the molten pool temperature,height and width of parts becomes larger;as the scanning speed increasing, the temperature of the molten pool decreases, height and width of parts becomes smaller.Forming height is directly affected by temperature gradient which is affected by different scanning routes; The change reason of both molten pool temperature and layer size was analyzed base on energy input. These results would provide the guidance for optimizing process parameters and scanning path base of the real-time infrared detection molten pool temperature to improve the forming quality.

In laser mental deposition, in order to ensure the forming quality of specimens,the key factor is to find mutual matching process parameters.Using many groups of contrast test, influence law that the process parameters on the of deposition surface forming quality is inquired by changing respectively laser power, scanning speed, send powder rate and the scanning interval. According to the law, the process parameters and powder melting rate relationship formula is summed up. And a series of mutual matching process parameters is calculated.

In order to obtain the characteristic parameters of molten pool and realize real-time control of laser power, a high-speed CCD is used to monitor the laser rapid forming process of thin-walled rotating hollow cone, which is based on the technology of "hollow beam, powder tube center, inside-beam powder feeding".Experiments show that: In the plateau stage, pool area changes in 0.25～0.70 mm2, laser power remains at about 1 kW, formed parts achieves maximum height of 55 mm.

In this study, using dispersed phase model in ANSYS FLUENT 12.0, the gas-solid two-phase flow field of the developed new type of laser coaxial inside-beam composite powder and wire feeding is three-dimensionally numerically simulated. The effects on the flow field from inlet pressure of shielding gas and the carrier gas flow rate are analyzed. The simulation results indicate that during the coaxial inside-beam powder and wire feeding laser cladding, peripheral shielding gas has very good concentration and collimation effects on the powder beam. The higher the inlet pressure of shielding gas is, the better the powder beam is concentrated. However, too high carrier gas flow rate leads to an enlarged divergence angle of the powder grain flow which is a little far from the composite nozzle.

7050 aluminum alloy fastener holes were strengthened by laser shock peening with Nd: glass pulse laser and pulse duration 30ns. The means of hardening fastener holes were laser shock peening on the dog-bone fatigue specimens before drilling fastener hole on the center of shocked areas, then fatigue testing was carried out under random loading spectrum of plane. The data of experiments show that: the fatigue life of fastener hole on specimens via laser shock peening is 1.5 times higher than those without peening, and the fractures show multiple fatigue crack sources is located under the surface. The density of dislocation in treated surface case is much higher than base material, because of the ultra-high plastic strain during laser shock peening. Distribution of compressive residual stress, relative low degree of cold work and high-density dislocation are conducive to fatigue performance. The results of study show that the laser shock peening can effectively improve the fatigue life of small-size fastener hole.

The system used to laser texturing and laser strength on roller surface was developed, This was composed of IPG5000 fiber laser, texturing system, strength system, processing machine and control system, The technology of Chopping disc, prism and the vibration mirror were used, The integration technology of laser hardening function and laser texturing function and disordered texturing technology were solved. The results show that the system has higher precision, stable and reliable. The system is suitable for laser texturing and laser strengthen for roller of Less than 800 mm in diameter and less than 5 500 mm in length or flat workpieces of less than 5 500 mm in length.

In order to study the effect of laser shock processing (LSP) on valve spring based on shot peening (SP) and heat setting, the valve spring manufactured by different processes were treated by LSP with high power Nd∶YAG laser. The effects of valve spring on mechanical properties after LSP were analyzed from residual stress, micro-hardness and microstructure. The results indicate that the effect on valve spring after LSP is similar to that after SP. The strengthening effect of valve spring by LSP based on SP is obvious. After LSP, the residual stress of valve spring based on shot peening twice reaches maximum value -541MPa and the micro-hardness of valve spring surface based on shot peening twice and heat setting reaches maximum value 668.4 HV. The variation of micro-hardness on valve spring surfaces manufactured by different processes after LSP is mostly identical to that before LSP. The grain refinement occurs after LSP and the primary cause of improving micro-hardness is grain size and strengthening phase.

This paper provided both the simulation and experiment results of the laser shock adjust surface residual stress (principal stress) state. Based on ABAQUS, we established the finite element analysis model of laser impinging on 5b05 aluminum alloy, and studied the relationship between different laser shock parameters and alloy’s surface residual stress state. The simulation results show that with the increase of the number of shocks the surface residual stress rise gradually. When the number of shocks is 3, the residual stress did not rise obviously. This indicates that the surface residual stress is becoming saturated. When shock pressure is constant, the surface residual stress rise with spot diameter, when the Radius of light spot increased to a certain degree the growing rate of surface peak residual compressive stress could reach minimum and stay almost constant. Compare the results of experiment and simulation we found that although the experimental value and the simulation results has certain error, the trend is almost the same, this illustrate that the model we have established is available.

The paper studies on low-pressure water jet assisted laser processing, and etches Al2O3 ceramics by using this method. A comprehensive study on the influence of laser processing parameters on surface quality of an Al2O3 ceramic sheet is presented. The surface quality of normal laser processing and low-pressure water jet assisted laser processing were comparative analyzed using a 3-D microscopy. Experiments proved that, the composite processing of low-pressure water jet assisted laser processing can obtain good surface quality, and lessen molten slags and thermal deformation , compared with the normal laser processing.

The quality of two-dimensional codes depends on laser parameters such as scanning speed, Q frequency, line spacing and laser power. The experiment changed the laser parameters and measured read bit rate of laser marking with two-dimensional code readers to study the influence of laser parameters on marking effect. The results show that perfect two-dimensional codes are obtained with about 10% of spot overlap and smaller line spacing through coordination the frequency, filling interval and speed.

During the pulse laser discrete scratching process, laser shock wave dynamic loading and interface failure are completed instantly. It contains debond, crack extension, warping, fracture and peeling which are often unable to distinguish. In order to accurately determine the critical point of the coating failure and propose a strain method to dialysis film-substrate system failure, this paper researched dynamic strain on coating surface of different theoretical models under pulse laser processing using PVDF patch sensors. The theoretical models are composed by double-sided adhesive binder, 2024 aluminum alloy substrate and 304 stainless steel foil film. The results indicate that under laser shock processing the dynamic strain on the coating surface fluctuates constantly, and then tends to steady. The whole process is finished in microseconds. The dynamic response of the coating surface is associated with interface bonding status of film-substrate system. When the film-substrate system combined well, the dynamic response's duration is long and the final strain value is small. When the film-substrate system debonded completely, the duration of the dynamic response is short and the obtained strain value is big. If the film- substrate system just began to debond, the situation will between this two pole conditions.

In the experiment, we use pulsed laser to conduct discrete scratching on Ni-containing stainless steel protective coating, and measured residual stress of the area, which discrete scratched by laser ,by the X350A ray diffraction system. We studied the residual stress status and analyzed the effects of laser shock waves stress on interfacial binding strength of film coating. The results show that in the center region of coating by laser loaded produced a uniform residual compressive stress, however, compressive residual stress decreases sharply even lead to surface tensile residual stress at the edge of the region. The study also indicates that the value of the residual compressive stress of coating, discrete scratching by laser, increase with increasing power density of laser. However, when the power density of laser is near to the threshold value, the residual compressive stress has decreased because the film begin to crack initiation and de-bonding. When the laser energy density is large enough, the strong shock waves can lead to tensile stress, crazed and broken of interface between Ni-containing and substrate at the spot edge of the region.

In order to investigate the melting mechanism between CO2 laser and Polyamide materials, the melting experiment of PA 12 was carried out by low-power CO2 laser with static or scanning way under room temperature, and the morphology of melted samples have been examined by means of light microscopy, scanning electron microscopy (SEM) and X-ray Diffraction (XRD), meanwhile, the effect of laser irradiation method and process parameters to melting samples was analyzed. It can be seen that the melting of sample was not obvious with beam 2 mm and power ＜ 1 W, while experimental samples were got pyrogenic ablation with laser power ＞3 W during irradiating, so power intensity 0.32 W/mm2 is the sample melting threshold. The surface of samples can be melted by static irradiation, while melting depth of samples will increase with the increased laser power and scanning times, and the crystalline of melted samples have obviously improved after irradiation. The results of experiment were in good agreement with theoretical research, which will provide guidance for Polyamide materials micro-processing by CO2 laser.

Metal alloy composition changes will influence the metal mechanical properties, so quantitatively analyze the alloy composition during laser machining become very important。In this paper, the composition change of 7075 aluminum metal alloy was determined by calibration-free laser-induced breakdown spectroscopy during laser machining。The influence of different machining condition (laser pulse width) was also investigated。The experiment result shows that the concentration of magnesium in molten metal is lower than was present in the base metal。And the Mg loss increases with increasing pulse width of the laser machining。It can be seen that the selective vaporization of different elements are affected by the pulse width of laser machining.

The laser machining is often accompanied by the generation of plasma phenomena. So study of plasma diagnostics will help to understand the physical mechanism of laser machining. In this paper, electron temperature of plasma was investigated theoretically and experimentally by laser-induced breakdown spectroscopy. The methods of line pair ratio, Boltzmann plot and Saha-Boltzmann plot were introduced to determine the electron temperature of T2 copper alloy. The experiment results showed that the precision of electron temperature calculated by line pair ratio method was poor while the Boltzmann plot and Saha-Boltzmann plot method which using several different lines lead to greater precision of the plasma temperature determination.

As a kind of the common used structural material in solar PV system, Polycrystalline silicon had always been studied as a focus. In order to study the interaction mechanism between different laser wavelengths and polycrystalline silicon, polycrystalline silicon surface was respectively irradiated by the single pulse laser with wavelengths of 532 nm & 1064 nm in this paper. The surface ablation morphology was observed by the optical microscope and analyzed under the different laser energy density. The physical mechanism of the crack initiation of material surface was explored. The results indicate that: under the wavelength of 1064 nm laser, firstly ablation area size is exponential distribution and then fits a linear distribution with the increasing of the laser energy density .And in the wavelength of 532 nm, ablation area size is linear distribution; Thermal stress is the largest in spot center and the most vulnerable to stress damage as irradiated by Gaussian laser; Two wavelengths laser irradiation Polycrystalline Silicon mainly damage mechanism are hot melting damage and the dissociation damage caused by transient thermal shock. Meanwhile, the former is more likely to happen.

Poly silicon are more widely used in the manufacture of solar cells because of its increasingly sophisticated manufacturing process and low cost. Due to the high efficiency, low consumption characteristics, the laser processing technology plays an important role in the field of solar cell manufacturing. In order to explore the impact of the laser processing parameters on the effects of processing, Based on orthogonal test method, by laser processing in polycrystalline silicon wafer surface for single point multiple pulse punch experiment method and through the optical microscope and three dimensional profilometer to analyze and observe experimental results, this paper established the relationship between process parameters and laser drilling morphology effects and optimized parameter that laser shock polysilicon tablet with, analyzed the heat affected zone around the hole. And the test got the best aperture laser processing parameters: With the action time 45s, laser wavelength of 532 nm, energy 120 mJ and spot diameter 0.5 mm.

A high energy and high stability Nd∶glass laser had been developed. Using ceramic tight package pumping cavity, a phosphate Nd∶glass rod that was pumped by two pulse xenon lamps and plane-parallel cavity resonator , it realized the output of high energy. Appling ray tracing software, the pumping light field of Nd∶glass laser rod is simulated in convergent cavity, the distribution of pump light was analyzed and the design of convergent cavity is optimized. Using main circuit of laser power supply that adopts charging circuit of series resonance of half bridge inverter type and control circuit that applies control technology of PID, it developed high stability output of laser power supply. Through the experiment analysis, the output single pulse energy of Nd∶glass is 200 J, and the pulse width is 2ms, the output stability of laser energy is ±0.7%, conversion efficiency of electricity-light is 1.9% , and beam quality M2 is 1.5.

Today, soil heavy metal pollution is serious. It’s necessary to design a handheld, field and in-situ soil heavy metal detector. A lens is used to focus the laser beam on the sample. A paraboloidal mirror and a separate lens group are used to collect the plasma optical signal into the optical fiber. A paraboloidal mirror and a gluing lens group are used to image the target point to the matglass. The size of the light spot on the sample is suitable; the coupling efficency of the light which is collected into the optical fiber is high and the numetical aperture of the light satisfies the requirement of the selected fiber; the target point is imaged clearly to the matglass; the length, width and height of the whole optical system are separately less than 30cm, 25cm and 10cm, and therefore the system is compact, small-sized and easy to carry. The result shows that the system is suitable for non-contact, field and in-situ soil heavy metal detection.

Remanufacturing technology is geared to resource saving and sustainable development．In this article, diode laser and its application in remanufacturing are introduced, and the obstacles against this application as well as the development trend of diode laser remanufacturing system are analyzed. Diode laser is fit to join into low-consumption and flexible laser remanufacturing system for its high electrical-to-optical conversion efficiency, small mass and body, and high absorption by metal. High-power diode laser units have been delivered to customer and are working for remanufacturing at home and abroad. Recently, the mobile diode laser remanufacturing equipment with a robot has also come into application. It is thought that the key to optical shaping and coupling will be found, and the obstacles against cladding with the appropriate materials on a variety of worn components will also be surmounted. Moreover, the robot technology relevant to diode laser remanufacturing is advancing, and the detection and control system for laser remanufacturing process is being developed. It is certain that components with any size, any shape and any material will be well remanufactured with diode laser in the further.

It is a effective measure to improve the solar cells conversion efficiency and reduce the manufacture cost. At present, there is a long time since laser process technology has been used by solar cell manufacturer, this indicates that it is feasible to use laser process technology for photovoltaic industry. In this paper, the new trends of laser process technologies used for photovoltaic industry are stated, especially, laser cutting, non-contact process technology, laser etching, laser sweeping, laser drilling. Based on above mentioned, the research on laser technology in photovoltaic industry is not enough sufficient. There has little means to overcome the encounter problem, but it will become a new research, even to inland or international.

Objective: Investigating the effect of CsA for reducing fibrous tissue hyperplasia after KTP Nd∶YAG laser recanalisation, guide the clinical use of medicine to reduce lacrimal duct stenosis relapse. Method: Making the animal model of lacrimal duct obstruction, dividing them into two groups, and injecting saline solution and CsA separately. Result: The appearance of lacrimal duct part obstruction and fibrous tissue hyperplasia is later in the CsA group, and the fibrous tissue hyperplasia is lighter. Conclusion: CsA can reduce fibrous tissue hyperplasia after KTP Nd: YAG, and improve the success rate of KTP Nd: YAG laser recanalization.

Objective: To investigate the clinical efficacy and side effects of the combination therapy of Er∶YAG and Q532 laser on recurrent Café-au-lait Spots. Methods: 16 cases of patients with recurrent Café-au-lait Spots were treated with combination therapy every 8 weeks. Firstly, the Er∶YAG laser was used to precisely vaporize the superficial tissue of lesions, then the lesions were scanned with Q532 nm laser until the treatment area became gray. The appropriate treatment parameters were selected according to the response of the treatment area. Results: Among the 16 patients after 4～9 treatments, 10 cases were cured, 3 cases marked effective, 2 cases moderate effective, 1 cases invalid with a total effective rate of 93.75%. No cases of aggravated pigmentation and scar formation were noted. Conclusion: The combination therapy of Er∶YAG and Q532 laser is an effective and safe treatment to recurrent Café-au-lait Spots.