针对YS3118数控滚齿机传动元件多而复杂导致其存在传动误差无法保证加工精度的情况,基于误差流(SOV,stream of variation)理论,以YS3118数控滚齿机主轴传动系统为研究对象,提出了运用状态空间模型描述此传动系统的误差流传递的方法.构...针对YS3118数控滚齿机传动元件多而复杂导致其存在传动误差无法保证加工精度的情况,基于误差流(SOV,stream of variation)理论,以YS3118数控滚齿机主轴传动系统为研究对象,提出了运用状态空间模型描述此传动系统的误差流传递的方法.构建描述传动件齿轮几何特征的坐标系,对加工误差或装配误差导致的转动副偏差进行数学建模,结合运动学理论描述出齿轮传动中包含误差参数的坐标系转换,并运用状态空间模型建立出传动过程误差流传递的表达形式,最终通过计算实例,验证了此方法的有效性.展开更多
Objective To evaluate the effect of dynein inhibitor on mouse oocyte in vitro maturation and its cyclin B1 transcription level. Methods Immature mouse oocytes were cultured in vitro with a known dynein ATPase activ...Objective To evaluate the effect of dynein inhibitor on mouse oocyte in vitro maturation and its cyclin B1 transcription level. Methods Immature mouse oocytes were cultured in vitro with a known dynein ATPase activity inhibitor-sodium orthovanadate (SOV) to detect the changes of maturation rate, and semi-quantitative RT-PCR and single cell RT-PCR were performed to detect the changes of cyclin B1 mRNA level. Results In dose-dependent experiments, the maturation rates of oocytes were significantly different between 5 mmol/L SOV and control groups (P<0.05), and decreased with SOV increasing doses. However, the elevation of cyclin B1 mRNA level of immatured oocytes cultured for 12 h depended on SOV concentrations ranging from 50 to 500 mmol/L. In incon- tinuity exposed SOV experiments, the maturation rates of oocytes markedly reduced after the first incubation with 400 mmol/L SOV at least for 1 h and were first cultured in SOV-free medium for 4 h or 8 h before exposure to SOV (P<0.05). In time-course experiment, the opposite changes of cyclin B1 mRNA level in oocytes between SOV and control groups were observed. Conclusion Dynein inhibitor might delay oocytes meiosis process, and cause ectopic expression of cyclin B1 in oocytes. Most Oocytes incubated with SOV blocked at germinal vesicles (GV) stage or MⅠto anaphase transition due to dynein dysfunction and ectopic transcription level of cyclin B1.展开更多
We propose a method to generate specially shaped high-order singular beams of pre-designed intensity distributions. Such a method does not a priori assume a phase formula, but rather relies on the 'cake-cutting an...We propose a method to generate specially shaped high-order singular beams of pre-designed intensity distributions. Such a method does not a priori assume a phase formula, but rather relies on the 'cake-cutting and assembly' approach to achieve the azimuthal phase gradient for beam shaping, inspired by the orbital motion trajectory change of an artificial satellite. Based on our method, several typical vortex beams with desired intensity patterns are experimentally generated. As an example, we realize optical trapping and transportation of microorganisms with a triangle-shaped vortex beam, demonstrating the applicability of such unconventional vortex beams in optical trapping and manipulation.展开更多
文摘针对YS3118数控滚齿机传动元件多而复杂导致其存在传动误差无法保证加工精度的情况,基于误差流(SOV,stream of variation)理论,以YS3118数控滚齿机主轴传动系统为研究对象,提出了运用状态空间模型描述此传动系统的误差流传递的方法.构建描述传动件齿轮几何特征的坐标系,对加工误差或装配误差导致的转动副偏差进行数学建模,结合运动学理论描述出齿轮传动中包含误差参数的坐标系转换,并运用状态空间模型建立出传动过程误差流传递的表达形式,最终通过计算实例,验证了此方法的有效性.
基金This work was supported by a grant from the National Natural Science Foundation of China (No. 30170481).
文摘Objective To evaluate the effect of dynein inhibitor on mouse oocyte in vitro maturation and its cyclin B1 transcription level. Methods Immature mouse oocytes were cultured in vitro with a known dynein ATPase activity inhibitor-sodium orthovanadate (SOV) to detect the changes of maturation rate, and semi-quantitative RT-PCR and single cell RT-PCR were performed to detect the changes of cyclin B1 mRNA level. Results In dose-dependent experiments, the maturation rates of oocytes were significantly different between 5 mmol/L SOV and control groups (P<0.05), and decreased with SOV increasing doses. However, the elevation of cyclin B1 mRNA level of immatured oocytes cultured for 12 h depended on SOV concentrations ranging from 50 to 500 mmol/L. In incon- tinuity exposed SOV experiments, the maturation rates of oocytes markedly reduced after the first incubation with 400 mmol/L SOV at least for 1 h and were first cultured in SOV-free medium for 4 h or 8 h before exposure to SOV (P<0.05). In time-course experiment, the opposite changes of cyclin B1 mRNA level in oocytes between SOV and control groups were observed. Conclusion Dynein inhibitor might delay oocytes meiosis process, and cause ectopic expression of cyclin B1 in oocytes. Most Oocytes incubated with SOV blocked at germinal vesicles (GV) stage or MⅠto anaphase transition due to dynein dysfunction and ectopic transcription level of cyclin B1.
基金National Key R&D Program of China(2017YFA0303800)National Natural Science Foundation of China(11674180,91750204)+1 种基金PCSIRT(IRT_13R29)Higher Education Discipline Innovation Project(B07013)
文摘We propose a method to generate specially shaped high-order singular beams of pre-designed intensity distributions. Such a method does not a priori assume a phase formula, but rather relies on the 'cake-cutting and assembly' approach to achieve the azimuthal phase gradient for beam shaping, inspired by the orbital motion trajectory change of an artificial satellite. Based on our method, several typical vortex beams with desired intensity patterns are experimentally generated. As an example, we realize optical trapping and transportation of microorganisms with a triangle-shaped vortex beam, demonstrating the applicability of such unconventional vortex beams in optical trapping and manipulation.
