A VBHF(Variable Blank Holder Force) optimization strategy was employed to determine the optimal time-variable and spatial-variable BHF trajectories,aiming at improving the formability of automobile panels with aluminu...A VBHF(Variable Blank Holder Force) optimization strategy was employed to determine the optimal time-variable and spatial-variable BHF trajectories,aiming at improving the formability of automobile panels with aluminum alloy sheet.The strategy was implemented based on adaptive simulation to calculate the critical wrinkling BHF for each segmented binder of the Numisheet' 05 deck lid in a single round of simulation.The thickness comparison of the stamped part under optimal VBHF and constant BHF shows that the variance of the four sections is decreased by 70%,44%,64% and 61%,respectively,which indicates significant improvement in thickness distribution and variation control.The investigation through strain path comparison reveals the fundamental reason of formability improvement.The study proves the applicability of the new VBHF optimization strategy to complex parts with aluminum alloy sheet.展开更多
Using squeezing transform in the context of quantum optics and based on the Fourier series expansion we rigorously derive a new Poisson sum formula. Application of this new formula to the representation transformation...Using squeezing transform in the context of quantum optics and based on the Fourier series expansion we rigorously derive a new Poisson sum formula. Application of this new formula to the representation transformation of kq-wave function for describing electrons in periodic lattice is demonstrated. In so doing, the transition matrix element of harmonic oscillator in kq representation is derived.展开更多
In this paper a fast output sampling （FOS） estimator is designed for estimation of state-space variables of DC-DC boost converter. Estimated state-space variables are output voltage of the converter and its first de...In this paper a fast output sampling （FOS） estimator is designed for estimation of state-space variables of DC-DC boost converter. Estimated state-space variables are output voltage of the converter and its first derivative, which are suitable for model reference adaptive controllers and sliding mode controllers design. Estimator is designed for operation in continuous and discontinuous conduction modes. The simulation results show that proposed FOS estimator provides good estimation of state-space variables despite the voltage ripple caused by high frequency switching in converter and disturbances （change of load and input voltage）.展开更多
Background and objective： Stroke volume variation（SVV） has high sensitivity and specificity in predicting fluid responsiveness. However, sinus rhythm（SR） and controlled mechanical ventilation（CV） are mandatory ...Background and objective： Stroke volume variation（SVV） has high sensitivity and specificity in predicting fluid responsiveness. However, sinus rhythm（SR） and controlled mechanical ventilation（CV） are mandatory for their application. Several studies suggest a limited applicability of SVV in intensive care unit（ICU） patients. We hypothesized that the applicability of SVV might be different over time and within certain subgroups of ICU patients. Therefore, we analysed the prevalence of SR and CV in ICU patients during the first 24 h of Pi CCO-monitoring（primary endpoint） and during the total ICU stay. We also investigated the applicability of SVV in the subgroups of patients with sepsis, cirrhosis, and acute pancreatitis. Methods： The prevalence of SR and CV was documented immediately before 1241 thermodilution measurements in 88 patients. Results： In all measurements, SVV was applicable in about 24%. However, the applicability of SVV was time-dependent： the prevalence of both SR and CV was higher during the first 24 h compared to measurements thereafter（36.1% vs. 21.9%; P0.001）. Within different subgroups, the applicability during the first 24 h of monitoring ranged between 0% in acute pancreatitis, 25.5% in liver failure, and 48.9% in patients without pancreatitis, liver failure, pneumonia or sepsis. Conclusions： The applicability of SVV in a predominantly medical ICU is only about 25%–35%. The prevalence of both mandatory criteria decreases over time during the ICU stay. Furthermore, the applicability is particularly low in patients with acute pancreatitis and liver failure.展开更多
基金Project(50934011) supported by the National Natural Science Foundation of ChinaProject(20080430085) supported by the China Postdoctoral Science Foundation
文摘A VBHF(Variable Blank Holder Force) optimization strategy was employed to determine the optimal time-variable and spatial-variable BHF trajectories,aiming at improving the formability of automobile panels with aluminum alloy sheet.The strategy was implemented based on adaptive simulation to calculate the critical wrinkling BHF for each segmented binder of the Numisheet' 05 deck lid in a single round of simulation.The thickness comparison of the stamped part under optimal VBHF and constant BHF shows that the variance of the four sections is decreased by 70%,44%,64% and 61%,respectively,which indicates significant improvement in thickness distribution and variation control.The investigation through strain path comparison reveals the fundamental reason of formability improvement.The study proves the applicability of the new VBHF optimization strategy to complex parts with aluminum alloy sheet.
基金Supported by the President Foundation of Chinese Academy of Sciencethe Specialized Research Fund for the Doctorial Progress of Higher Education in China under Grant No. 20070358009
文摘Using squeezing transform in the context of quantum optics and based on the Fourier series expansion we rigorously derive a new Poisson sum formula. Application of this new formula to the representation transformation of kq-wave function for describing electrons in periodic lattice is demonstrated. In so doing, the transition matrix element of harmonic oscillator in kq representation is derived.
文摘In this paper a fast output sampling （FOS） estimator is designed for estimation of state-space variables of DC-DC boost converter. Estimated state-space variables are output voltage of the converter and its first derivative, which are suitable for model reference adaptive controllers and sliding mode controllers design. Estimator is designed for operation in continuous and discontinuous conduction modes. The simulation results show that proposed FOS estimator provides good estimation of state-space variables despite the voltage ripple caused by high frequency switching in converter and disturbances （change of load and input voltage）.
文摘Background and objective： Stroke volume variation（SVV） has high sensitivity and specificity in predicting fluid responsiveness. However, sinus rhythm（SR） and controlled mechanical ventilation（CV） are mandatory for their application. Several studies suggest a limited applicability of SVV in intensive care unit（ICU） patients. We hypothesized that the applicability of SVV might be different over time and within certain subgroups of ICU patients. Therefore, we analysed the prevalence of SR and CV in ICU patients during the first 24 h of Pi CCO-monitoring（primary endpoint） and during the total ICU stay. We also investigated the applicability of SVV in the subgroups of patients with sepsis, cirrhosis, and acute pancreatitis. Methods： The prevalence of SR and CV was documented immediately before 1241 thermodilution measurements in 88 patients. Results： In all measurements, SVV was applicable in about 24%. However, the applicability of SVV was time-dependent： the prevalence of both SR and CV was higher during the first 24 h compared to measurements thereafter（36.1% vs. 21.9%; P0.001）. Within different subgroups, the applicability during the first 24 h of monitoring ranged between 0% in acute pancreatitis, 25.5% in liver failure, and 48.9% in patients without pancreatitis, liver failure, pneumonia or sepsis. Conclusions： The applicability of SVV in a predominantly medical ICU is only about 25%–35%. The prevalence of both mandatory criteria decreases over time during the ICU stay. Furthermore, the applicability is particularly low in patients with acute pancreatitis and liver failure.
