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试验研究硬态切削气门座圈表面粗糙度
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作者 桂武 杨海东 +1 位作者 夏锡全 庆振华 《合肥工业大学学报(自然科学版)》 CAS 北大核心 2018年第9期1174-1177,共4页
文章使用聚晶立方氮化硼(polycrystalline cubic boron nitride,PCBN)刀具硬态切削粉末冶金气门座圈,研究表面粗糙度的影响因素。采用单因素试验,以不同刀尖圆弧半径在不同切削参数下硬态切削。试验结果表明:刀尖圆弧半径rε对表面粗糙... 文章使用聚晶立方氮化硼(polycrystalline cubic boron nitride,PCBN)刀具硬态切削粉末冶金气门座圈,研究表面粗糙度的影响因素。采用单因素试验,以不同刀尖圆弧半径在不同切削参数下硬态切削。试验结果表明:刀尖圆弧半径rε对表面粗糙度Ra影响最大,Ra随rε的增大先明显降低后略微升高,在rε≈0.3mm时,Ra最小;切削速度v对Ra影响较小,Ra随v的增大而降低。因此,为避免切削深度ap和进给量f过小而引起的切削区材料挤压、打滑,ap和f的取值应在一个合理范围,在高v、较大的ap和f下可获得更好的Ra。 展开更多
关键词 硬态切削 气门座圈 刀尖圆弧半径 切削参数 表面粗糙度
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Theoretical studies of structures and spectroscopic properties of [(tpy)(bpy)RuC≡CC_6H_4R]^+(tpy = 2,2′:6′,2″-terpyridine, bpy = 2,2′-bipyridine; R = F, Cl, H, Me and OMe) 被引量:1
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作者 xia xiquan ZHANG Hui ZHANG GuiLing 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第4期725-733,共9页
A series of polypyridine ruthenium (II) acetylide complexes, [(tpy)(bpy)RuC≡CC6H4R]^+ (tpy = 2,2':6',2"-terpyridine, bpy = 2,2'-bipyridine; R = F (1), C1 (2), H (3), Me (4) and OMe (5)) are in... A series of polypyridine ruthenium (II) acetylide complexes, [(tpy)(bpy)RuC≡CC6H4R]^+ (tpy = 2,2':6',2"-terpyridine, bpy = 2,2'-bipyridine; R = F (1), C1 (2), H (3), Me (4) and OMe (5)) are investigated theoretically to explore their electronic structures and spectroscopic properties. Their ground/excited state geometries, electronic structures and spectroscopic properties are first calculated using density functional theory (DFT) and time-dependent DFT (TDDFT). The absorption and emission spectra of the complexes in acetonitrile solution are also obtained by using TDDFT (B3LYP) method associated with the CPCM model. The calculations show that the energy levels of HOMOs for 1-5 are sensitive to the substituent on phenylacetylide ligand and increase with the same order of the electron-donating ability of the substituents; however, those of polypyridine-based LUMOs vary slightly. The lowest-energy absorptions and emissions for 1-5 are progressively red-shifted in the order of 1 ~ 2 〈 3 〈 4 〈 5 when the electron-donating groups are introduced into the phenylacetylide [igand. The phosphorescence of 1 are attributed to {[dxz(Ru) +π(C≡C)]→[π^*(tpy)]} (3MLCT/3LLCT) transition, whereas those of 2-5 are originated from { [dxz/dxy(Ru)+ π(C ≡C)+g(C6H4R)] → [*(tpy/bpy)] } (3MLCT/3LLCT) transitions. 展开更多
关键词 polypyridine ruthenium (II) acetylide complexes absorption spectra emission spectra DFT TDDFT
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