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  1. Article: Multidimensional Study on the Wear of High-Speed, High-Temperature, Heavy-Load Bearings.

    Wang, Dongfeng / Yuan, Julong / Hu, Lai / Lyu, Binghai

    Materials (Basel, Switzerland)

    2023  Volume 16, Issue 7

    Abstract: The friction and wear performance of high-performance bearings directly affects the accuracy and maneuverability of weapons and equipment. In this study, high-speed, high-temperature, and heavy-load durability experiments of weapon bearings were carried ... ...

    Abstract The friction and wear performance of high-performance bearings directly affects the accuracy and maneuverability of weapons and equipment. In this study, high-speed, high-temperature, and heavy-load durability experiments of weapon bearings were carried out, and their wear properties (i.e., surface wear, metamorphic layer, scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS), residual stress, and retained austenite) were analyzed in multiple dimensions. The results showed the following: (1) The experimental temperature of the serviced front-end bearing is always lower than that of the rear bearing. (2) The metamorphic layer of the serviced rear bearing (i.e., inner ring, outer ring, rolling body, and cage) > the metamorphic layer of the serviced front-end bearing > the metamorphic layer of the unserviced bearing. (3) The rolling body of the rear bearing at high experimental temperatures contains not only elemental O, but also elemental P and Sr. (4) In the EDS analysis of the rolling elements, with the migration from the "ball edge" to the "ball center", the elemental C in the rolling elements of serviced or unserviced bearings decreases slowly, while the elemental Fe content increases slowly.
    Language English
    Publishing date 2023-03-29
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma16072714
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Surface Modification of Silicon Carbide Wafers Using Atmospheric Plasma Etching: Effects of Processing Parameters.

    Jin, Qi / Yuan, Julong / Zhou, Jianxing

    Micromachines

    2023  Volume 14, Issue 7

    Abstract: Silicon carbide wafer serves as an ideal substrate material for manufacturing semiconductor devices, holding immense potential for the future. However, its ultra-hardness and remarkable chemical inertness pose significant challenges for the surface ... ...

    Abstract Silicon carbide wafer serves as an ideal substrate material for manufacturing semiconductor devices, holding immense potential for the future. However, its ultra-hardness and remarkable chemical inertness pose significant challenges for the surface processing of wafers, and a highly efficient and damage-free method is required to meet the processing requirements. In this study, atmospheric plasma processing was used to conduct point-residence experiments on silicon carbide wafers by varying process parameters such as Ar, CF
    Language English
    Publishing date 2023-06-29
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2620864-7
    ISSN 2072-666X
    ISSN 2072-666X
    DOI 10.3390/mi14071331
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Study of Atmospheric Pressure Plasma Temperature Based on Silicon Carbide Etching.

    Xu, Shaozhen / Yuan, Julong / Zhou, Jianxing / Cheng, Kun / Gan, Hezhong

    Micromachines

    2023  Volume 14, Issue 5

    Abstract: In order to further understand the excitation process of inductively coupled plasma (ICP) and improve the etching efficiency of silicon carbide (SiC), the effect of temperature and atmospheric pressure on plasma etching of silicon carbide was ... ...

    Abstract In order to further understand the excitation process of inductively coupled plasma (ICP) and improve the etching efficiency of silicon carbide (SiC), the effect of temperature and atmospheric pressure on plasma etching of silicon carbide was investigated. Based on the infrared temperature measurement method, the temperature of the plasma reaction region was measured. The single factor method was used to study the effect of the working gas flow rate and the RF power on the plasma region temperature. Fixed-point processing of SiC wafers analyzes the effect of plasma region temperature on the etching rate. The experimental results showed that the plasma temperature increased with increasing Ar gas until it reached the maximum value at 15 slm and decreased with increasing flow rate; the plasma temperature increased with a CF
    Language English
    Publishing date 2023-05-02
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2620864-7
    ISSN 2072-666X
    ISSN 2072-666X
    DOI 10.3390/mi14050992
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Experimental Study on Shear Rheological Polishing of Si Surface of 4H-SiC Wafer.

    Li, Peng / Yuan, Julong / Zhu, Minghui / Zhou, Jianxing / Lyu, Binghai

    Micromachines

    2023  Volume 14, Issue 4

    Abstract: In this study, shear rheological polishing was used to polish the Si surface of six-inch 4H-SiC wafers to improve polishing efficiency. The surface roughness of the Si surface was the main evaluation index, and the material removal rate was the secondary ...

    Abstract In this study, shear rheological polishing was used to polish the Si surface of six-inch 4H-SiC wafers to improve polishing efficiency. The surface roughness of the Si surface was the main evaluation index, and the material removal rate was the secondary evaluation index. An experiment was designed using the Taguchi method to analyze the effects of four critical parameters (abrasive particle size, abrasive particle concentration, polishing speed, and polishing pressure) on the Si surface polishing of SiC wafers. By evaluating the experimental results for the signal-to-noise ratio, the weight of each factor was calculated using the analysis of variance method. The optimal combination of the process parameters was obtained. Below are the weightings for the influence of each process on the polishing result. A higher value for the percentage means that the process has a greater influence on the polishing result. The wear particle size (85.98%) had the most significant influence on the surface roughness, followed by the polishing pressure (9.45%) and abrasive concentration (3.25%). The polishing speed had the least significant effect on the surface roughness (1.32%). Polishing was conducted under optimized process conditions of a 1.5 μm abrasive particle size, 3% abrasive particle concentration, 80 r/min polishing speed, and 20 kg polishing pressure. After polishing for 60 min, the surface roughness, R
    Language English
    Publishing date 2023-04-14
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2620864-7
    ISSN 2072-666X
    ISSN 2072-666X
    DOI 10.3390/mi14040853
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Material Removal Characteristics of Spherical-Array-Focused Ultrasonic Abrasive Machining.

    Du, Bo / Wang, Jinhu / Yuan, Julong / Lyu, Binghai / Zhang, Xinqian / Zhang, Chunyu

    Micromachines

    2023  Volume 14, Issue 2

    Abstract: To improve the ultrasonic energy and realize far-field ultrasonic abrasive machining of complex surfaces, a spherical-array-focused ultrasonic abrasive machining system was established. By combining ultrasonic field simulation, detection and a single- ... ...

    Abstract To improve the ultrasonic energy and realize far-field ultrasonic abrasive machining of complex surfaces, a spherical-array-focused ultrasonic abrasive machining system was established. By combining ultrasonic field simulation, detection and a single-factor experiment, the influences of the ultrasonic generator current, abrasive concentration, and particle size on the material removal properties and surface quality evolution of quartz glass were investigated. When the current was less than 0.4 A, the material removal showed plastic removal at the nanoscale. When the current was more than 0.5 A, the cavitation phenomenon formed micron-scale impact removal traces on the workpiece surface. The increase in abrasive concentration increased the impact density and material removal rate, while excessive abrasive concentration increased the impeding effect between abrasive particles and reduced the material removal rate. Moreover, the increase in abrasive particle concentration enhanced heterogeneous cavitation nucleation, promoted the removal of abrasive impact materials under the action of a cavitation jet, and inhibited the removal of direct surface cavitation. The abrasive particle size affects the heterogeneous cavitation nucleation and the acceleration of the cavitation jet on abrasive particles, which affects the material removal rate and surface quality. By controlling the energy of the focused ultrasound and abrasive parameters, the plastic or brittle domain removal of quartz glass can be achieved at the micro- and nanoscales.
    Language English
    Publishing date 2023-02-03
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2620864-7
    ISSN 2072-666X
    ISSN 2072-666X
    DOI 10.3390/mi14020382
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Book ; Conference proceedings: Advances in abrasive technology XVI

    Yuan, Julong

    selected, peer reviewed papers from the 16th International Symposium on Advances in Abrasive Technology (ISAAT 2013), in conjunction with the 17th Chinese Conference of Abrasive Technology (CCAT 2013), September 23-26, 2013, Hangzhou, China

    (Advanced materials research ; 797)

    2013  

    Event/congress Chinese Conference of Abrasive Technology, CCAT (17, 2013.09.23-26, Hangzhou) ; International Symposium on Advances in Abrasive Technology, ISAAT (16, 2013.09.23-26, Hangzhou)
    Author's details ed. by Julong Yuan
    Series title Advanced materials research ; 797
    Language English
    Size XVI, 767 S.
    Publisher Trans Tech Publ
    Publishing place Durnten-Zurich u.a.
    Document type Book ; Conference proceedings
    ISBN 9783037858257 ; 3037858257
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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  7. Article: Effect of Wetting Characteristics of Polishing Fluid on the Quality of Water-Dissolution Polishing of KDP Crystals.

    Wang, Xu / Gao, Hang / Deng, Qianfa / Wang, Jinhu / Chen, Hongyu / Yuan, Julong

    Micromachines

    2022  Volume 13, Issue 4

    Abstract: KDP crystals constitute the only laser-frequency conversion and electro-optical switches that can be used in laser systems for inertial confinement fusion. However, KDP crystals are difficult to produce because of their inherent softness, brittleness, ... ...

    Abstract KDP crystals constitute the only laser-frequency conversion and electro-optical switches that can be used in laser systems for inertial confinement fusion. However, KDP crystals are difficult to produce because of their inherent softness, brittleness, water-solubility, and temperature sensitivity. The authors' group developed a water-dissolution polishing method in previous studies to obtain near-damage-free KDP surfaces. In this article, the effect of the wetting characteristics of the water dissolution polishing fluid on the crystal surface-a factor rarely considered in the usual process optimization-on the polished surface quality was comprehensively studied. The mean radius of micro water droplets at 5 wt.% and 7.5 wt.% water content was approximately 0.6 nm and 1.2 nm, respectively. Theoretically, the smaller micro water droplet size is beneficial to the polished surface quality. When the water content was 5 wt.%, due to the poor wetting characteristics of the polishing fluid, surface scratches appeared on the polished surface; when the water content was 7.5 wt.%, the effects of the wetting characteristics and the radius of the micro water droplets reached a balance, and the polished surface quality was the best (Ra 1.260 nm). These results confirm that the wetting characteristics of the polishing fluid constitute one of the key factors that must be considered. This study proves that the wetting characteristics of the polishing fluid should be improved during the optimization process of polishing fluid composition when using oil-based polishing fluids for ultra-precision polishing.
    Language English
    Publishing date 2022-03-29
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2620864-7
    ISSN 2072-666X
    ISSN 2072-666X
    DOI 10.3390/mi13040535
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Research on Monocrystalline Silicon Micro-Nano Structures Irradiated by Femtosecond Laser.

    Liu, Yanan / Ding, Ye / Xie, Jichang / Chen, Mingjun / Yang, Lijun / Lv, Xun / Yuan, Julong

    Materials (Basel, Switzerland)

    2022  Volume 15, Issue 14

    Abstract: Femtosecond (fs) laser processing has received great attention for preparing novel micro-nano structures and functional materials. However, the induction mechanism of the micro-nano structures induced by fs lasers still needs to be explored. In this work, ...

    Abstract Femtosecond (fs) laser processing has received great attention for preparing novel micro-nano structures and functional materials. However, the induction mechanism of the micro-nano structures induced by fs lasers still needs to be explored. In this work, the laser-induced periodic surface structure (LIPSS) of monocrystalline silicon (Si) under fs laser irradiation is investigated. Three different layers named amorphous silicon (a-Si) layer, transition layer, and unaffected Si layer are observed after laser irradiation. The a-Si layer on the surface is generated by the resolidification of melting materials. The unaffected Si layer is not affected by laser irradiation and maintains the initial atomic structure. The transition layer consisting of a-Si and unaffected Si layers was observed under the irradiated subsurface. The phase transition mechanism of Si irradiated by fs laser is "amorphous transition", with the absence of other crystal structures. A numerical model is established to describe the fs laser-Si interaction to characterize the electronic (lattice) dynamics of the LIPSS formation. The obtained results contribute to the understanding of fs laser processing of Si at the atomic scale as well as broaden the application prospects of fs laser for treating other semiconductor materials.
    Language English
    Publishing date 2022-07-14
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma15144897
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article: Investigation on the Basic Characteristics of Semi-Fixed Abrasive Grains Polishing Technique for Polishing Sapphire (α-Al

    Lei, Yang / Feng, Ming / Wu, Ke / Chen, Jinxi / Ji, Jianghao / Yuan, Julong

    Materials (Basel, Switzerland)

    2022  Volume 15, Issue 11

    Abstract: Single-crystal sapphire (α- ... ...

    Abstract Single-crystal sapphire (α-Al
    Language English
    Publishing date 2022-06-03
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma15113995
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: Shear Thickening Polishing of Quartz Glass.

    Shao, Qi / Duan, Shixiang / Fu, Lin / Lyu, Binghai / Zhao, Ping / Yuan, Julong

    Micromachines

    2021  Volume 12, Issue 8

    Abstract: Quartz glass is a typical optical material. In this research, colloidal silica ( ... ...

    Abstract Quartz glass is a typical optical material. In this research, colloidal silica (SiO
    Language English
    Publishing date 2021-08-13
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2620864-7
    ISSN 2072-666X
    ISSN 2072-666X
    DOI 10.3390/mi12080956
    Database MEDical Literature Analysis and Retrieval System OnLINE

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