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| 1 | Apparent diffusion coefficient in normal and abnormal pattern of intervertebral lumbar discs: initial experience显示文摘The aim of the present study was to compare the relationship of morphologically defined non-bulging/herni-ated, bulging and herniated intervertebral lumbar discs with quantitative apparent diffusion coefficient (ADC). Thirty-two healthy volunteers and 28 patients with back pain or sciatica were examined by MRI. All intervertebral lumbar discs from L1 to S1 were classified according to morphological abnormality and degenerated grades. The ADC values of nucleus pulposus (NP) were measured and recorded. The significant differences about mean ADC values of NP were found between non-bulging/herniated discs and bulging discs as well as herniated discs (P < 0.05), whereas there were no significant differences in ADC values between bulging and herniated discs (P > 0.05). Moreover, statistically significant relationship was found in the mean ADC values of NP between 'non-bulging/herniated and non-degenerated discs' and 'non-bulging/herniated degenerated discs' as well as herniated discs (P < 0.05). Linear regression analysis between ADC value and disc level revealed an inverse correlation (r = -0.18). The ADC map of the NP is a potentially useful tool for the quantitative assessment of componential and molecular alterations accompanied with lumbar disc abnormalities. | Gang Niu Xuewen Yu Jian Yang Rong Wang Shaojuan Zhang Youmin Guo | 2011 | The Journal of Biomedical Research2011，25，3： | 7 |
| 2 | Shape evolution of monolayer MoS2 crystals grown by chemical vapor deposition显示文摘 | WANG Shanshan RONG Youmin FAN Ye | 2014 | Chem Mater2014，26，22： | 1 |
| 3 | Analysis and comparison of laser cutting performance of solar float glass with different scanning modes显示文摘Cutting quality and efficiency have always been important indicators of glass laser cutting.Laser scanning modes have two kinds,namely,the spiral and concentric circle scanning modes.These modes can achieve high-performance hole cutting of thick solar float glass using a 532-nm nanosecond laser.The mechanism of the glass laser cutting under these two different scanning modes has been described.Several experiments are conducted to explore the effect of machining parameters on cutting efficiency and quality under these two scanning modes.Results indicate that compared with the spiral scanning mode,the minimum area of edge chipping(218340µm)and the minimum Ra(3.01µm)in the concentric circle scanning mode are reduced by 9.4%and 16.4%respectively.Moreover,the best cutting efficiency scanning mode is 14.2%faster than that in the spiral scanning mode.The best parameter combination for the concentric circle scanning mode is as follows:Scanning speed:2200 mm/s,number of inner circles:6,and circle spacing:0.05 mm.This parameter combination reduces the chipping area and sidewall surface roughness by 8.8%and 9.6%respectively at the same cutting efficiency compared with the best spiral processing parameters.The range of glass processing that can be achieved in the concentric circle scanning mode is wider than that in the spiral counterpart.The analyses of surface topography,white spots,microstructures,and sidewall surface element composition are also performed.The study concluded that the concentric circle scanning mode shows evident advantages in the performance of solar float glass hole cutting. | Wenyuan LI Yu HUANG Youmin RONG Long CHEN Guojun ZHANG Zhangrui GAO | 2021 | Frontiers of Mechanical Engineering2021，16，1： | 1 |
| 4 | Multiple-Model Estimation with Variable Structure Part Ⅲ:Model-Gruup Switching Algorithm显示文摘 | X Rong Li Xiaorong Zhi Youmin Zhang | 1999 | IEEE Transactions On Aerospace and Electronic Systems1999，35，1： | 1 |
| 5 | Ultrafast laser-chemical modification hybrid fabrication of hydrostatic bearings with a superhydrophobicity solid-liquid interface显示文摘Oil film vortex severely reduces the stability of hydrostatic bearings. A solid-liquid interface with drag and slip properties can weaken the oil film vortex of the bearing. Here, a combined picosecond laser ablation and chemical modification method is proposed to prepare surfaces with microbulge array structure on 6061 aluminum alloy substrates. Because of the low surface energy of the perfluorododecyltriethoxysilane modification and the bulge geometry of the microbulge array structure, the surface shows excellent superhydrophobicity. The optimum contact angle in air for water is 164°, and that for oil is 139°. Two surfaces with “lotus-leaf effect” and “rose-petal effect” were obtained by controlling the processing parameters. The drag reduction properties of superhydrophobic surfaces were systematically investigated with slip lengths of 22.26 and 36.25 μm for deionized water and VG5 lubricant, respectively. In addition, the superhydrophobic surface exhibits excellent mechanical durability and thermal stability. The proposed method provides a new idea for vortex suppression in hydrostatic bearings and improves the stability of bearings in high-speed operation. | GUO MingHui RONG YouMin HUANG Yu FENG XiaoLin HU HaiDong WU CongYi ZHANG GuoJun | 2024 | Science China(Technological Sciences)2024，67，3： | 0 |
| 6 | WeldNet:A voxel-based deep learning network for point cloud annular weld seam detection显示文摘Weld seam detection is an important part of automated welding.At present,few studies have been conducted on annular weld seams,and a lot of defects exist in the point cloud model of the tube sheet obtained by RGB-D cameras and photography methods.Aiming at the above problems,this paper proposed an annular weld seam detection network named WeldNet where a voxel feature encoding layer was adaptively improved for annular weld seams,the sparse convolutional network and region proposal network(RPN)were used to detect annular weld seam position,and an annular weld seam detection loss function was designed.Further,an annular weld seam dataset was established to train the network.Compared with the random sampling consistency(RANSAC)method,WeldNet has a higher detection accuracy,as well as a higher detection success rate which has increased by 23%.Compared with U-Net,WeldNet has been proven to achieve a better detection result,and the intersection over the union of the weld seam detection is improved by 17.8%. | WANG Hui RONG YouMin XU JiaJun XIANG SongMing PENG YiFan HUANG Yu | 2024 | Science China(Technological Sciences)2024，67，4： | 0 |
| 7 | Laser cutting of thermoplastic film:Mechanism and processing technology显示文摘The mechanism of ultraviolet(UV) nanosecond laser cutting of thermoplastic films and the influence of process parameters on process quality are systematically discussed.The photothermal effect plays a dominant role in the interaction between the UVnanosecond laser and thermoplastic materials.In this photothermal reaction,a heat source with the focal point as the core is formed,around which a thermal carbonization layer,a thermal melting layer,and a thermal expansion layer are formed in order from the inside to the outside.Among them,the thermal carbonization layer is not prevalent,and the thermal melting layer and thermal expansion layer are prevalent.The process quality can be adjusted by adjusting the cutting speed,the laser power,and the repetition number of cuts to regulate the process of heat generation and heat dissipation.In the effective range,the faster the cutting speed and the lower the laser power,the smaller the kerf width and heat-affected zone(HAZ) width.Within a certain range,the depth of kerf can be increased by increasing the repetition number of cuts. | WU CongYi RONG YouMin HUANG Yu ZHANG GuoJun | 2022 | Science China(Technological Sciences)2022，65，9： | 0 |
| 8 | Dimethicone-aided laser cutting of solar rolled glass显示文摘Solar rolled glass,with one micro-structure surface and another roughness surface,can cause diffuse refraction of the focused laser spot,and this phenomenon restricts the application of laser manufacturing.In this study,laser cutting of solar rolled glass with a thickness of 2.5 mm was successfully achieved with the help of dimethicone to ensure laser focusing.Dimethicone was coated on the top surface of the rolled glass processing zone,and a bottom–up multilayer increment with the spiral line was applied to control the cutting path.Different viscosity values of dimethicone were considered.Results showed that surface quality increased as the viscosity increased until a certain threshold was reached;afterward,the surface quality decreased or directly caused the cutting to fail.The minimum surface roughness(3.26µm)of the processed surface(chipping:Width≤113.64µm,area 215199µm)was obtained when the dimethicone viscosity and laser pulse frequency were 1000 mm/s and 43 kHz(power 25.4 W),respectively.The micro-defects on the processed surface were few,and the edge chipping width and depth of the laser processed surface were small. | Wenyuan LI Guojun ZHANG Long CHEN Yu HUANG Youmin RONG Zhangrui GAO | 2021 | Frontiers of Mechanical Engineering2021，16，1： | 0 |
| 9 | Revealing the interaction mechanism of pulsed laser processing with the application of acoustic emission显示文摘The mechanisms of interaction between pulsed laser and materials are complex and indistinct,severely infuencing the stability and quality of laser processing.This paper proposes an intelligent method based on the acoustic emission(AE)technique to monitor laser processing and explore the interaction mechanisms.The validation experiment is designed to perform nanosecond laser dotting on foat glass.Processing parameters are set diferently to generate various outcomes:ablated pits and irregular-shaped cracks.In the signal processing stage,we divide the AE signals into two bands,main and tail bands,according to the laser processing duration,to study the laser ablation and crack behavior,respectively.Characteristic parameters extracted by a method that combines framework and frame energy calculation of AE signals can efectively reveal the mechanisms of pulsed laser processing.The main band features evaluate the degree of laser ablation from the time and intensity scales,and the tail band characteristics demonstrate that the cracks occur after laser dotting.In addition,from the analysis of the parameters of the tail band very large cracks can be efciently distinguished.The intelligent AE monitoring method was successfully applied in exploring the interaction mechanism of nanosecond laser dotting foat glass and can be used in other pulsed laser processing felds. | Weinan Liu Youmin Rong Ranwu Yang Congyi Wu Guojun Zhang Yu Huang | 2023 | Frontiers of Optoelectronics2023，16，2： | 0 |
| 10 | Lattice Boltzmann study on the effects of surface nanostructure on wettability with application in laser scanning fabrication of superhydrophobic surfaces显示文摘Nanostructured surfaces with dimensions on a scale of a few millimeters exhibit remarkable hydrophobicity.The geometry of these nanostructures considerably affects their wettability.However,determining the optimal geometry is challenging due to the abundance of geometry parameters and the difficulty in numerically describing their effects on wettability at the mesoscopic scale.In addition,the fabrication of nanostructured surfaces with precise geometries is challenging.We establish a lattice Boltzmann method(LBM)model to address these challenges.We use the model to gain mesoscopic insights into the interaction between droplets and nanostructures.Our model can accurately reproduce contact angles(CAs)on various nanostructured surfaces and enables investigation of the effects of nanostructure geometry on wettability.We optimize the geometry of the nanostructures using the insights provided by the LBM model on the wettability mechanisms.Our analysis indicates that cones with dimensions of 40μm in width and 33μm in height exhibit the highest hydrophobicity.We successfully fabricate a superhydrophobic surface with the desired geometry via laser scanning,achieving a CA of 163°.We believe that this approach,which combines the LBM model and laser manufacturing,will enable a better understanding of the wettability mechanism and provide a high-performance approach for fabricating superhydrophobic surfaces. | HUANG Hao GUO MingHui WU CongYi RONG YouMin HUANG Yu ZHANG GuoJun | 2023 | Science China(Technological Sciences)2023，66，11： | 0 |
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