排序方式: 共有45条查询结果,搜索用时 0 毫秒
11.
锥齿轮-斜齿轮减速机的轴向力分析 总被引:1,自引:0,他引:1
对锥齿轮——斜齿轮减速机在不同旋向、转动方向的条件下分析轴向力的大小和方向。优化弧齿锥齿轮的旋向组合,可以避免轴向力叠加,从而改善减速机齿轮轴和箱体的受力情况,提高轴承和减速机的寿命。 相似文献
12.
13.
The La-dopping effect on the piezoelectricity in the K0.5Na0.5NbO3 (KNN) crystal with a tetragonal phase is investigated for the first time using the first-principle calculation based on density functional theory. The full potentiallinearized augumented plane wave plus local orbitals (APW-LO) method and the supercell method are used in the calculation for the KNN crystal with and without the La doping. The results show that the piezoelectricity originates from the strong hybridization between the Nb atom and the O atom, and the substitution of the K or Na atom by the La impurity atom introduces the anisotropic relaxation and enhances the piezoelectricity at first and then restrains the hybridization of the Nb-O atoms when the La doping content further increases. 相似文献
14.
15.
16.
17.
18.
19.
20.
气相色谱法测定蔬菜、水果中百菌清、三唑酮及菊酯类农药 总被引:1,自引:0,他引:1
以黄瓜为代表,以乙腈为提取剂,用石英毛细管色谱柱进行分离,电子捕获检测器检测的气相色谱法测定蔬菜中的百菌清、三唑酮、甲氰菊酯、三氟氯氰菊酯、氯氰菊酯、氰戊菊酯农药残留。以保留时间定性,外标法面积定量,6种农药的检测限分别为0.0005mg/kg、0.0009mg/kg、0.0014mg/kg、0.0011mg/kg、0.0012mg/kg、0.0013mg/kg,相对标准差均〈7.6%,加标回收率在76.5%~101.5%之间。该方法比较简便,满足了蔬菜、水果食用安全的鉴别要求。 相似文献