By combining numerical simulation and experimental investigation, this paper intensively investigated the influence rules of adding SiO2 active agent on the dynamic behaviors of flow field in the laser welding 304 stainless steel thick plate pool. First of all, the mathematical model of the activating laser welding stainless steel thick plate was constructed to numerically investigate the impact of active agents on the fluid flow in the pool. Secondly, based on the tungsten particle tracing principle test, the high speed camera system was adopted for real-time monitoring to investigate the mechanism of action of the active agents on the flow field in the pool. The results suggested that, the active agent partially affected the mode of fluid flow. The velocity vector from both sides of the pool to the center occurred on the pool surface, while vortex from the pool margin to the center occurred on the pool cross section. It was suggested from the phenomenon that the tracing tungsten particles moving from the pool margin to the center that, it shows that the flow direction of the fluid changed after coating with the active agent, the fluid flew from the pool margin to the center. At the same time, the coating of active agents changed the flow velocity of fluid inside the pool, the maximum velocity of fluid flow on the upper surface, the vertical section and the cross section at the same position of the active agent coated specimen increased by 25.8%, 8% and 33.8%, respectively, compared with that without the active agents.

Two welds of lock joint were processed by laser deep penetration welding, and X-ray digital radiography (DR) inspection and micro-computed tomography (micro-CT) inspection were carried out, the depth distribution characteristics of pores in lock joint by laser welding were researched. Firstly, the DR image of pores distribution in plate-like lock joint by laser welding was analyzed. Then, the three-dimensional structure of the lock joint weld was reconstructed by micro-CT, 134 and 126 pores were extracted respectively from lock joint welds of No.1 and No.2, and the pore diameter was quantitatively analyzed. The pore depth distribution characteristics were analyzed by the position of the pore center, and the pore distribution information within and outside the effective welding depth range were obtained. The results showed that most of the pores in the two lock joint welds were less than 1 mm in diameter, and 73.1% and 64.3% of the pores in No.1 and No.2 lock joint welds were distributed in the same depth range. Finally, in accordance with the X-ray acceptance standards of company’s laser weld, based on the X-ray DR inspection results and micro-CT inspection results, both lock joint welds were rated as grade Ⅲ.

Due to its superior properties, such as low density, high specific strength, excellent corrosion resistance, and good formability, aluminum alloy has become the main material for the light-weight manufacturing of high-speed train body. With the characteristics of low heat input, high welding speed, and high process stability, laser-MIG hybrid welding is a promising joining technology for the high-speed train aluminum alloy body with the features of low deformation, high efficiency, and high quality. In the present work, the welding characteristics of laser-MIG hybrid welding for 6 mm thickness 6082-T6 aluminum alloy was studied. The effects of welding parameters on the weld formation and porosity defects were investigated. The microstructure features, micro-hardness distribution, and mechanical properties were also researched. The results indicated that the full-penetration weld could be performed free of porosity in a wide range of laser power. The MIG current arc significantly affected the porosity positions, and the porosity mainly existed near the fusion line of when the MIG current greater than 150 A. The content and size of the porosity both increased as the welding speed increasing. It was beneficial for the reduction of the porosity rate when the heat source distance was around 3 mm, or the gas flow rate less than 25 L·min-1. The weld microstructure has consisted of the equiaxial crystal zone, columnar crystal zone, partly melted zone, and over-aging zone. The widths of the partly melted zone and over-aging zone in the arc affected zone were larger than that in the laser affected zone. There were two obvious softening areas in the heat affected area, which were located near the fusion line and 24 mm away from the fusion line. The average tensile strength of the joint was 255.1 MPa, which could reach up to 82.3% of the base material. The fracture occurred in the heat-affected zone, and the fracture propagation path was basically parallel with the fusion line. The fracture appearance of the laser-MIG hybrid welded joints belonged to the ductile fracture.

In this paper, microstructures of 316L austenitic stainless steel joints subjected to 0 mT and 18 mT longitudinal magnetic fields were studied. The change of morphology and texture of austenite (γ) and ferrite (δ) phases were primarily analyzed concerning fused line, columnar zone and central zone. When the magnetic field intensity was change from 0mT to 18mT, the upper hybrid welding layer changed from “T shape” to “triangle shape”, accelerating the heat transfer instead of the heat convergence in the heat affected zone and increasing the temperature gradient of the solid/liquid front. At the fusion line, the addition of magnetic field changed the growth direction of δ phase from ［1 0 0］to ［2 0 3］, deviating from the normal direction of fusion line (［1 0 0］) And the crystal texture changed from (0 1 6)［21 0］to (2 3 3)［32 0］. However, the increase of temperature gradient led to the concentration of ［1 0 0］crystal direction distribution. In the columnar zone, the addition of magnetic field altered the growth direction of δ phase from ［1 0 0］to ［2 1 2］, also deviating from the theoretical temperature gradient direction (［1 0 0］). And the crystal texture changed from (0 3 1)［91 3］to (3 10 2)［21 2］with the increased fraction of the special δ/γ orientation relationships. In the central zone, the growth direction of δ phase was changed from ［1 0 5］to ［1 0 3］and gradually deviated from the theoretical temperature gradient direction (［0 0 1］) with the addition of magnetic field. And the crystal texture was altered from (1 0 0)［01 5］to (1 0 0)［0 3 1］with a reduced fraction of the special δ/γ orientation relationships.

A 10 kW fiber laser was used to conduct the experimental study on the Fe-based TiC coating by laser cladding in this paper .Effect of different TiC content on the macroscopic quality of Fe-based cladding was discussed. Optical microscope was adopted to reveal the microstructure and phase structure of the coatings. Furthermore, a MM-U10G type friction wear tester was used to measure the wear resistance of the coatings. Results show that, the surface of laser cladding layer with different TiC content is formed smoothly. With the improvement of TiC mass fraction, Ti content of cladding layer increases continuously and the cracking tendency increases. When the TiC mass fraction was 0, the microstructure of the cladding layer was mainly dendrite with uniform microstructure. When the TiC mass fraction was 10%, the second phase occurs. And with the increase of TiC content, the number of the second phase increases, the particle size is larger, the distribution is denser, and the microhardness of cladding layer also increases. When the TiC mass fraction is 30%, the hardness of the cladding layer is the highest overall, which is ranging from 920-1 400 HV. The wear resistance of cladding layer is also increasing with the improvement of TiC content.

The cumulative plastic deformation and microstructure of 0Gr18Ni9Ti nickel-based coating materials under different impact frequencies were compared and analyzed on the self-developed cam multi-impact tester. The results show that the larger the impact frequency is, the greater the cumulative plastic deformation is, and the finer the microstructure is at the same depth, but the plastic deformation becomes slower as the impact frequency increases proportionally, and when the impact frequency increases to a certain value, no plastic deformation occurs, and the change of microstructure becomes smaller and smaller. Impact frequency is an important factor to study the accumulative plastic deformation mechanism of 0Gr18Ni9Ti Ni-based coating material under low stress and multiple impact.

The effect of applied laser and magnetic field on narrow gap arc welding of 10 mm thick SUS316L austenitic stainless steel was studied. The results show that the arc in narrow gap arc welding is difficult to be stable in the narrow gap, and the sharp Angle at the bottom of groove cannot be heated. Under the appropriate laser power, the arc in the narrow gap can burn stably. However, too large a laser parameter will cause the arc to move up and will not be able to heat the sharp Angle at the bottom of the groove. Under the action of constant magnetic field, the arc in the narrow gap swings to one side, beyond the narrow gap range, and the other side cannot fill the narrow gap. With the increase of magnetic field strength, the asymmetry becomes more obvious. Under the action of alternating magnetic field, the left and right skewness of arc appears alternately, and the shape is almost the same as that of constant magnetic field. Under the action of laser, the laser induced plasma causes the arc to gather and burn stably at the hole. When a magnetic field is added, the charged particles rotate, and their uneven distribution in the arc causes the arc to aggregate on the left or right side. Therefore, a change in the direction of the magnetic field causes the arc to swing alternately on the left and the right sides.

The processing parameters have an important influence on the performance of the parts during the selective laser melting (SLM) process. Therefore, in this study, the influence of different scanning speeds and laser powers on the performance of the Ti6Al4V alloy parts fabricated by selective laser melting have been investigated, mainly including the fracture behavior of the parts. The fracture mechanism of Ti6Al4V alloy parts fabricated by selective laser melting has been also studied by investigating their microstructures. The experimental results show that: The fracture morphologies of the Ti6Al4V alloy parts under different processing parameters are significantly different. The size of grains at the fracture and internal pores defects of the Ti6Al4V alloy parts can be effectively adjusted by selecting different scanning speeds and laser powers. Through the analysis of the fracture morphology of Ti6Al4V alloy parts, the optimized processing parameters are obtained: laser power of 240 W, scanning speed of 1 200 mm/s, powder layer thickness of 0.03 mm and hatch spacing of 0.14 mm. At this time, the tensile strength of Ti6Al4V alloy parts can reach 1 179 MPa.

In this study, we investigated the influence of process parameters on the relative density of MS1 alloy manufactured by selective laser melting (SLM). The effect of post-heat treatments with 850 ℃×1 h solid solution + 550 ℃×4 h aging process on the microstructure and mechanical properties was elucidated. The SLMed MS1 alloy with high density and high performance was achieved. The results show that the structure of the SLM as-built alloy is mainly composed of lath marensite and austenite, with small size and uniform distribution, but there are tiny shrinkage holes in the as-bulit alloy. The post-heat treatments improve the as-built structure of MS1 alloy and eliminate pore defects. After heat treatment, much strengthening phases are precipitated in MS1 alloy, which increases its strength and reduces the ductility. The yield strength is increased by more than 1 time, the tensile strength is increased by more than 70%, the hardness is increased by more than 82%, and the elongation rate is reduced from 10.7% to 5.6%.

As an alloy suitable for selective laser melting (SLM) process, rare earth elements doped aluminum alloy has been widely used due to its superior mechanical properties and good formability. The forming quality is determined by the processing parameters. In this paper, by controlling key process parameters such as laser power, scanning velocity and hatch spacing, the evolution of relative density and defect types of SLM rare earth elements doped aluminum alloys at different process parameters are studied. The results show that changes in process parameters will lead to changes in energy density, the relative density of the alloy is affected by the volumetric energy density and the liner energy density of the single pass. When the volumetric energy density is 70-180 J/mm3 and the liner energy density is 0.250-0.525 J/mm, the relative density of the alloy is stable above 99.5%.

The effects of laser scanning speed on microstructure, hardness and friction and wear properties of TiB2/S136 composites in laser selective melting process controlled by PLC were studied by means of X-ray diffraction, scanning electron microscopy, hardness tester and friction and wear tester. The results show that the main phases of the formed parts are α-Fe, γ-Fe and TiB2 under four different laser scanning speeds; with the decrease of laser scanning speed, the compactness of the formed parts first increases and then decreases, and when the laser scanning speed is 700 mm/s, the maximum value (98.4%) is obtained, and there are no obvious holes or microcracks in the formed parts. With the decrease of laser scanning speed, the hardness, average friction coefficient and wear rate of XY and YZ surfaces of the formed parts decrease first and then increase. When the laser scanning speed is 700 mm/s, the maximum hardness, the minimum average friction coefficient and wear rate are obtained, which is mainly due to the high compactness, fine and uniform grains and high hardness are related to the shape.

A methane pump shell is formed by selective laser melting of AlSi10Mg alloy powder, namely 3D printing rapid prototyping technology. But the methane pump shell is found to have interlayer cracks running through the contour after forming. The chemical composition of the material was detected by spectrograph and inductively coupled plasma emission spectrometer(ICP), the mechanical properties was tested by universal testing machine, the macroscopic morphology of the crack was analyzed by stereomicrograph, the microstructure of the fracture was analyzed by field emission scanning electron microscope, and the microstructure of the crack and the matrix was detected by the material microscope. The results show that the crack on the inner cavity surface of AlSi10Mg methane pump shell is actually the defect of interlayer unfusion during laser forming of the aluminum alloy shell. The reason is that the laser oscillator instability lead to low power and scanning speed is too fast.

Selective laser melting (SLM) technology is widely used in the additive manufacturing of three-dimensional complex parts, but due to the instantaneous high temperature of the laser, it is easy to generate thermal stress on the parts and affect the processing quality. In this paper, a Ti6Al4V three-dimensional finite element simulation model is established, and the SLM deposition forming process is simulated to explore the influence of the inter layer idle time of the double-layer multi-channel deposition model on the temperature distribution and thermal stress evolution. The results show that the simulated molten pool is in good agreement with the experimental results, which verifies the accuracy of the model. After the first layer is deposited, from the surface temperature distribution the cooling effect is remarkable. The increase of the idle time makes the heat conduction conditions better. After cooling, the X-direction stress presents a "sawtooth" distribution, and the maximum stress appears at the lap joint. As the inter layer idle time increases from no stay to 60s, the X-direction stress gradually decreases, maximum drop of 30%; the Y-direction stress presents a "Convex" and "Concave" distribution. The residual stress is distributed in a "Stripe" along the scanning direction; the maximum stress of the top path in the Y-direction first increases and then decreases, and the stresses of the Middle and Bottom paths show a decreasing trend. Therefore, appropriate inter layer idle time can stabilize the heat conduction, effectively reduce the residual stress after cooling.

Due to the rapid melting and solidification leads to complex transient temperature distribution during the selective laser melting (SLM) forming process, the molten pool and the cooling rate affect the final solidified structure, which affects the quality of the part. In this paper, a three-dimensional transient finite element model is established to numerically simulate the forming process of a single-channl multilayer SLM of GH4169 alloy to study the transient temperature distribution, molten pool size and cooling rate; and the influence of different linear energy density on the single-channl multi-layer SLM forming. The results show that when the linear energy density is 170 J/m, with the increase of the number of layers, the maximum temperature of the molten pool, the size of the molten pool and the heat-affected zone gradually become larger, and the upper layer has a remelting effect on the lower layer; except for the first layer, the cooling rate increases slightly with the increase of the number of layers. With the increase of the linear energy density, the maximum temperature of the molten pool at the center point of the fifth layer increases, and the the size of the molten pool and the heat-affected zone become large, the cooling rate increases with the increase of the linear energy density. Forming thin-walled wall samples with different linear energy densities, then comparing and analyzing the simulation results, a better consistency is obtained.

In order to study the path planning of nanosecond pulse laser in single microstructure, the temperature variation and ablation removal of micro-pits were simulated by using COMSOL Multiphysics finite element simulation software. The accuracy and efficiency of single-point pits are affected by the time and power of laser, and the prediction data model is established, the simulation results show that the pit radius r2∝ ln(t), the depth and time are linear, and the volume is quadratic distribution with time. Based on the simulation data model, the principle of multi-point strike planning is explored to find the optimal overlap ratio, and the feasibility is verified by experiments.

The aero-engine parts have complex structures, small size, and poor beam accessibility. In order to explore the strengthening effect of laser oblique shock peening technique on GH4169 superalloy materials, this paper studies the effect of laser shock peening process parameters on the surface and depth residual stress, surface roughness and microhardness through laser oblique shock peening experiments. The results show that the surface and depth residual stress, microhardness and surface roughness increase with the increase of laser energy and impact times; when the (5 J, 6 J, 7 J) energy collocation is adopted, the index value obtained is relatively the best, the surface roughness value is 1.08 μm, the surface residual compressive stress is -446.9 MPa, the residual compressive stress layer depth is 1 500 μm, the microhardness is 448.1 HV and the depth of influence is 1 300 μm.

Aiming at the problem of low cost and real-time shape-follow cleaning of large freeform surface workpiece in engineering application, a robotic laser cleaning control system was designed with STM32 as the main control chip. A two-dimensional scanning laser cleaning head is installed at the end of the robot to realize laser scanning. STM32 communicates with the robot controller through Ethernet, and cooperates with the robot controller by means of a laser rangefinder. The functions of focusing the freeform surface with shape and scanning and cleaning in blocks are completed. Finally, a large freeform surface workpiece is scanned and cleaned according to a S-path planning strategy, and the laser cleaning test is carried out. The results show that the control system has the characteristics of complete block splicing and good cleaning effect, and the cleaning efficiency can reach 0.396 m2/h.

This paper proposes a laser cleaning detection method for rust surface of steel based on the machine vision technology. The laser cleaning visual detection system is constructed, and the SURF algorithm is used to continuously splice the collected images. Based on the HSV color space conversion method, the HSV threshold of steel rust is obtained, and the median filtering method is used to remove the interference pixels. The results show that the laser cleaning detection method based on machine vision can realize the visual detection of steel rust surface during the laser cleaning process. In comparison with the gray threshold extraction method, the detection accuracy is improved, which can provide quantitative evaluation for the laser cleaning quality of steel rust surface.

When pulsed laser is used to clean insulators, the distribution characteristics of surface pollution are different, and the distribution of overall temperature and stress field are also different. This paper takes porcelain insulator and its surface pollution as the object, establishes the finite element model, analyzes the temperature field and stress field respectively for the surface non-uniform distribution and uniform distribution of porcelain insulator pollution, and verifies the cleaning effect by laser experiment. The results show that when the energy density is 1.41 J/cm2 and the scanning speed is 1 000 mm/s, the non-uniform pollution on the laser irradiation path can be completely removed, and the removal rate of the uniform distribution of pollution is affected by the thickness and focal length position. The larger thickness, means the closer the distance from the focus, causes the higher the temperature rise, the greater the tensile stress, and the higher the clearance rate. The smaller thickness, means the farther away from the laser focal length, causes the lower the pollution clearance rate. Therefore, the incident distance and laser power should be adjusted timely when cleaning uneven distribution of pollution. The results show that the laser cleaning is the most efficient and the surface is smooth and clean. In the other two cases, there is residual pollution on the surface.

Individual tree is the basic unit of forest. Accurate detection of individual tree and efficient parameter acquisition are of great significance to improving management quality and production efficiency of forestry. In order to solve the problem of selecting the method and parameters of individual tree segmentation in subtropical coniferous forest, the key segmentation parameters of the watershed algorithm, point cloud-based cluster segmentation and layer stacking will be explored. At the same time, the individual tree clusters segmentation results of the three algorithms will be compared, and combine the recognition results with actual measurement data to evaluate the segmentation accuracy. The test results show that when the point cloud-based cluster segmentation and layer stacking segment individual tree clusters, there are over-segmentation or under-segmentation. But the watershed algorithm has the best segmentation results and the highest segmentation accuracy.

Aiming at the problem of the detection blind zone in the glue detection of a single line structured light sensor, a method using three line structured light sensors to measure the colloid is proposed for three-dimensional measurement. The three line structured lights surround the glue gun to form a closed triangle The light knife is projected vertically to the surface of the workpiece to be coated for real-time online detection. The camera is calibrated by Zhang Zhengyou′s calibration method, and the light plane is calibrated by the least squares plane fitting method. The measurement accuracy of the three line structured light sensors is analyzed by measuring standard blocks. The measurement results show that the measurement errors of the sensors are all less than 0.15 mm, which meets the measurement requirements. Finally, design experiments to measure the colloid in three dimensions and analyze the impact factor of measurement accuracy. Obtain the three-dimensional point cloud data of the colloid profile and perform three-dimensional reconstruction to obtain the three-dimensional contour map of the colloid cross section. Finally, the two parameters of the width and height of the colloid are extracted and combined with compare the results of manual testing. Experiments show that it is feasible to use this method to measure the geometric parameters of colloids.

This paper introduces a constant fraction discrimination circuit with LVTTL level output. Through signal amplification, comparison and level conversion, the circuit is finally connected to FPGA chip, and the time measurement function is directly realized by delay chain in FPGA chip. The circuit adopts LVTTL level output, and the FPGA chip can directly identify the level. Compared with the traditional design, this design eliminates the special time measuring chip, saves the cost and takes into account the volume requirements. At the same time, the circuit is expected to solve the problems of high power consumption and low timing accuracy of lidar system.

In order to improve the calibration precision of the cross-structured light sensor, a cross structured-light calibrating method is proposed. A two-step algorithm for extracting the straight line feature of the imaging light strip and fit the pixel straight line equation in the pixel coordinate system. Through coordinate conversion, get The image line equation in the camera coordinate system is combined with the camera origin to find the plane equation. This plane equation is combined with the two-dimensional target plane equation in the camera coordinate system to solve the laser line equation in the camera coordinate system. Change the target posture, obtain multiple sets of intersecting light line information, and fit the cross laser plane using the principle of random sampling consistency. Finally, the three-dimensional reconstruction of the ring gauge standard parts and error analysis are carried out. The experiment measured the average value of the inner radius error of the ring gauge is 0.155 8 mm. This method makes full use of the point information on the straight line feature, solves the problem of fewer feature points in the previous fitting light plane algorithm, enhances the robustness of the algorithm, and has a certain practicability.

Based on the principle of SLM beam shaping, the structural characteristics of three type grating: binary grating, blazed grating and sinusoidal grating are analyzed. Phase masks with different periods of the three type gratings are designed according to the performance that affect the quality of shaping beam, taking square form as an example. Imaging and machined experiments show that all the phase mask formed by loading three type gratings on SLM can shape the gaussian circular beam into a flat-topped square, but the shaping effect of blazed gratings is obviously better than that of the other two gratings. When the grating period was 120 μm, the local energy utilization rate was 91.86%, and the RMSE was 0.039. Using blazed grating, the shaped beam has high energy efficiency and good uniformity.

With the development of automotive rear light technology, people have a higher pursuit of the personalized and three-dimensional image display function of automotive rear lights. In response to this situation, based on the principle of holographic technology, this paper proposes two holographic car taillight schemes, transmission type and reflection type, three-dimensional modeling of automotive rear lights, and production of automotive rear lights and optical components to realize the three-dimensional image display of automotive rear lights. The three-dimensional display effect and display performance parameters of holographic automotive rear lights were tested and analyzed. Among them, the diffraction efficiency of the transmissive holographic automotive rear light can reach 28.75%, and the light average transmittance is higher than 86.83%, which has a good three-dimensional display effect. Reflective holographic car taillights can also present clearer three-dimensional images under white light.

Cube corner reflector is widely used as the cooperative target in laser tracking, location and other systems, its far field diffraction intensity distribution is of great significance to the design of cooperative target as well as to the theoretical study on the performance of laser radar system. An analytic algorithm for calculating the diffraction intensity is presented in this paper, in which, the effective reflective area of corner reflector is approximately taken as an ellipse, and the reflected beam is decompose of a series of complex Gaussian functions. Thus the far-field diffraction field is expressed as the superposition of a series of elliptic Gaussian beam. Numerical results show that the relative error caused by this algorithm is less than 5% in most cases, therefore, this algorithm is a feasible.

To study the healing effect of different therapeutic doses of red light on acute wounds of type Ⅰ diabetes SD rats. 2 weeks after intraperitoneal injection of Streptozocin (60 mg/kg) solution, rats that peripheral blood sugar over 16.7 mmol/L were considered of diabetes models. Sixty diabetic rats were randomly divided into 5 groups: control group (L0, no treatment), treatment group 1 (L1, 12 J/cm2), treatment group 2 (L2, 24 J/cm2), treatment group 3 (L3, 48 J/cm2), and treatment group 4 (L4, 96 J/cm2). Two acute wounds were made symmetrically on both sides of the midline of the rat back with a hole punch of 8 mm diameter. One day later, wound was irradiated with red light of wavelength of 633 nm±10 nm at different energy densities of each group. The wounds were photographed on day 0, 3, 7 and 10 after punching. On day 3, 7 and 10, 4 rats were randomly selected for wound sampling. After paraffin embedding, HE staining, Masson staining, CD31 immunohistochemical staining and CD68 immunofluorescence staining were performed. Results: The wound healing rate showed that red light treatment can accelerate wound healing, and the effect of L3 group was most significant. HE showed that re-epithelialization of wounds in the treatment groups were accelerated and L3 was the best at day 7.CD31 immunohistochemical staining showed that treatment groups could promote angiogenesis and L3 and L4 were the most prominent.CD68 immunofluorescence showed that treatment groups could reduce the degree of wound inflammatory infiltration at the 10th day, and the positive rates of L2 and L3 were the lowest. Conclusion: Within the scope of the energy density of the experiment, red light can promote type Ⅰ diabetes SD rats back wound healing, and the most notable promoting effect energy density is 48 J/cm2.

Objective: To evaluate the safety and efficiency of transurethral low-power thulium laser en bloc resection of non muscle-invasive bladder tumor. Methods: total of 40 non muscle-invasive bladder tumor patients treated in our hospital from May 2017 to May 2019 were enrolled, including 25 male patients and 15 female patients with the average age of (64.15±10.35) years old. All the patients were treated with transurethral en bloc resection by using the VELA-thulium laser under low power of 15-20 W. Results: All the operations were finished successfully in one time under general anesthesia. The average time of operation was (25.54±7.13) min. No obturator nerve reflex, bladder perforation and massive bleeding was recorded intraoperatively. There was no severe urinary tract infection and blood loss postoperatively. The mean following-up time was (14.20±2.13) months. 3 cases(7.5%) had tumor recurrence. Conclusions: Transurethral low-power thulium laser en bloc resection is a safe and effective therapeutic method in treatment of non muscle-invasive bladder tumor.

Objective: To observe the effects of He-Ne laser irradiation combined with proton pump inhibitors (PPIs), gastric motility drug on reflux esophagitis. Methods: 126 RE patients were randomly divided into observation group and control group, with 63 cases each. The control group was treated with itopril and esomeprazole, the observation group was treated with laser irradiation on the basis of the control group. The differences of clinical efficacy, clinical symptom score, endoscopic grading score, esophageal dynamics indexes, the levels of gastrointestinal hormones and pepsinogens before and after treatment were compared between the two groups. Results: The total effective rate of the observation group (92.06%) was significantly higher than that of the control group (77.78%), and the difference was statistically significant (P<0.05). After treatment, clinical symptom scores such as heartburn, acid reflux, chest pain and endoscopic grading scores in both groups reduced (P<0.05), but compared with the control group, the clinical symptom scores and endoscopic grading scores of the observation group reduced significantly (P<0.05). After treatment, the pressure of esophageal sphincter was significantly increased in the two groups, and the vertical reflux time ratio, horizontal reflux time ratio and total reflux time ratio were significantly decreased (P<0.05), but the improvement degree of the above indicators in the observation group was greater than that in the control group (P<0.05). Compared with before treatment, GAS, MOT, PG Ⅰ, PG Ⅰ/PG Ⅱ after treatment significantly increased in the two groups (P<0.05), VIP decreased obviously (P<0.05), but the improvement of the above indexes in the observation group was greater than that in the control group (P<0.05).Conclusion: He-Ne laser irradiation combined with PPIs, gastric motility drug have a significant effect on RE, which is better than PPIs combined with gastric motility drug, and can effectively improve the esophageal dynamics and gastrointestinal hormone levels of the patients.