| 1 | Challenges and strategies in high-accuracy manufacturing of the world’s largest SiC aspheric mirror显示文摘In the process of manufacturing the world’s largest silicon carbide(SiC)aspheric mirror,the primary difficulties are mirror blank preparation,asphere fabrication,and testing,as well as cladding and coating.Specifically,the challenges include the homogeneity of the complicated structure casting,accuracy and efficiency of the fabrication process,print-through effect,fidelity and precision of test procedure,stress and denseness of cladding process,the dynamic range of interferometric measurement,and air turbulence error due to the long optical path.To break through such a barrier of difficulties,we proposed the water-soluble room temperature vanishing mold and gel casting technology,homogeneous microstructure reaction-formed joint technology,nano-accuracy efficient compound fabrication,gravity unloading technology,high-denseness low-defect physical vapor deposition(PVD)Si-cladding technology,test data fusion method,and time-domain averaging method,etc.Based on the proposed technologies and methods,we have accomplished the world’s largest SiC aspheric mirror with a size of φ4.03 m.The impressive performance of the SiC aspheric mirror is validated by the characteristics of the fabricated SiC aspheric mirror.The aerial density of the SiC blank is less than 120 kg/m^(2),surface shape test accuracy is better than 6 nm RMS,thickness inhomogeneity of the cladding layer is less than 5%,and the final surface figure error and roughness are 15.2 nm RMS and 0.8 nm RMS,respectively. | Xuejun Zhang Haixiang Hu Xiaokun Wang Xiao Luo Ge Zhang Wenxing Zhao Xiaoyi Wang Zhenyu Liu Ling Xiong Erhui Qi Congcong Cui Yanchao Wang Yingjie Li Xu Wang Longxiang Li Yang Bai Qiang Cheng Zhiyu Zhang Ruigang Li Wa Tang Xuefeng Zeng Weijie Deng Feng Zhang | 2022 | Light(Science & Applications)2022，11，12： | 3 |
| 3 | Synthesis, performance and structure characterization of glyoxal-monomethylolurea-melamine (G-MMU-M) co-condensed resin显示文摘In order to reduce the formaldehyde emission of formaldehyde-based wood adhesive from the source,it is aimed to develop a novel co-condensed resin of glyoxal-monomethylolurea-melamine(G-MMU-M).A series of G-MMU-M resins with various formulations of raw materials were successfully prepared.The basic properties and bonding performance of the G-MMU-M resins were determined.Furthermore,the structures of resins were characterized by FTIR,^(13)C NMR,XPS,and ESI-MS.The results show that the prepared G-MMU-M resin remains stable for 30 d,meanwhile,the dry and wet bonding strength of the plywoods bonded with the resins,solid content and viscosity are influenced greatly by the addition amount of melamine and MMU/G molar ratio.The G-MMU-M resins with MMU/G molar ratio of 0.9:1.0 and 8% melamine exhibit the highest dry and bonding strength of 1.98 MPa and 1.27 MPa,increased by 34% and 63%,respectively,in comparison with glyoxal-monomethylolurea(G-MMU)resin.In the G-MMU-M resins,there were four main oligomers including M—CH(—^(+)CH-MMU)-O-MMU,M-CH(—CH_(2)OH)-MMU-O-MMU,M—CH(—OH)—^(+)CH-MMU-O-MMU,and M—CH(—^(+)CH-MMU)-MMU-p-G. | Haixiang Liu Jun Zhang Chunlei Dong Gang Zhu Guanben Du Shuduan Deng | 2023 | Chinese Journal of Chemical Engineering2023，59，7： | 1 |
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