High-overload shocks are very likely to cause damage to the microstructure of MEMS devices, especially the continuous multiple high-overload shocks generated by the penetration of the multilayer target environment pos...High-overload shocks are very likely to cause damage to the microstructure of MEMS devices, especially the continuous multiple high-overload shocks generated by the penetration of the multilayer target environment pose more stringent challenges to its protective structure. In this study, the kinetic response model of the protective structure under single-pulse and continuous double-pulse impact is established,and a continuous double-pulse high overload impact test impact platform based on the sleeve-type bullet is constructed, and the protective performance of the multi-layer structure under multi-pulse is analyzed based on the acceleration decay ratio, and the results show that the protective performance of the structure has a positive correlation with its thickness, and it is not sensitive to the change of the load of the first impact;the first impact under double-pulse impact will cause damage to the microstructure through the superposition of the second impact. The first impact under double-pulse impact will cause an increase in the overload amplitude of the second impact through superposition;compared with the single-layer structure, the acceleration attenuation ratio of the double-layer structure can be increased by up to 26.13%, among which the epoxy-polyurethane combination has the best protection performance, with an acceleration attenuation ratio of up to 44.68%. This work provides a robust theoretical foundation and experimental basis for the reliable operation of MEMS devices, as well as for the design of protective structures in extreme environments.展开更多
BACKGROUND:Pulse indicated continuous cardiac output(PiCCO)has largely replaced Swan-Ganz catheterization in shock patients.However,whether PiCCO monitoring can improve outcomes of shock patients,such as mortality,len...BACKGROUND:Pulse indicated continuous cardiac output(PiCCO)has largely replaced Swan-Ganz catheterization in shock patients.However,whether PiCCO monitoring can improve outcomes of shock patients,such as mortality,length of hospital stay,duration of mechanical ventilation,or laboratory parameters,remains unknown.METHODS:This retrospective cohort study included patients with shock in the intensive care unit(ICU)from January 2013 to January 2020.Patients were divided into PiCCO group and non-PiCCO group based on treatment with PiCCO monitoring or not.Demographic characteristics,Acute Physiology and Chronic Health Evaluation(APACHE)II scores,quick Sequential Organ Failure Assessment(qSOFA)scores,14-day mortality,and N-terminal pro-B-type natriuretic peptide(NT-proBNP)levels at 0,1,3 and 7 days after onset of shock,duration of mechanical ventilation,length of hospital stay and hospitalization costs were compiled and analyzed using propensity score matching(PSM).RESULTS:Real-world analysis of 1,583 ICU patients suff ering shock after propensity score matching revealed that 14-day mortality did not differ between PiCCO and non-PiCCO groups(36.2%vs.32.6%,P=0.343).Duration of mechanical ventilation,hospital stay,and hospitalization costs were also similar between the two groups(P>0.05).No diff erences in changes of NT-proBNP levels on days 0,1,3,and 7 as compared to baseline were noted between the two groups(P>0.05).CONCLUSIONS:The results of our real-world indicate that PiCCO monitoring may not shorten the duration of mechanical ventilation,length of hospital stay,or reduce hospitalization costs,nor will it bring survival benefi ts to ICU patients suff ering shock.展开更多
The current research on pulse continuously variable transmission（CVT） is mainly focused on reducing the pulse degree and making pulse degrees a constant value. Current research mainly confined to find out new design...The current research on pulse continuously variable transmission（CVT） is mainly focused on reducing the pulse degree and making pulse degrees a constant value. Current research mainly confined to find out new design parameters by using the method of optimization, and reduce the pulse degree of pulse CVT and its range of variation. But the fact is that the reduction of the pulse degree is not significant. This article presents a new structure of mechanical pulse CVT--the rotational swashplate pulse CVT with driven by helical gear axial meshing. This transmission is simple and compact in structure and low in pulsatile rate （it adopts 6 guide rods）, and the pulsatile degree is irrelevant to the transmission ratio. Theoretically, pulsatile rate could be reduced to zero if appropriate curved surface of the swashplate is used. Compared with the connecting rod pulse CVT, the present struc^tre uses helical gear mechanism as transmission part and it avoids unbalanced inertial force in the former model. This paper analyzes the principle of driving of this transmission, presents its mechanical structure, and discusses its motion characteristics. Experimental prototype of this type of CVT has been manufactured. Tests for the transmission efficiency（when the rotational speed of the output shaft is the maximum） and the angular velocity of the output shaft have been carried out, and data have been analyzed. The experimental results show that the speed of the output shaft for the experimental prototype is slightly lower than the theoretical value, and the transmission efficiency of the experimental prototype is about 70%. The pulse degree of the CVT discussed in this paper is less than the existing pulse CVT of other types, and it is irrelevant to the transmission ratio of the CVT. The research provides the new idea to the CVT study.展开更多
<strong>Background</strong><strong>:</strong><b><span style="font-family:;" "=""> </span></b><span style="font-family:;" "=&qu...<strong>Background</strong><strong>:</strong><b><span style="font-family:;" "=""> </span></b><span style="font-family:;" "=""><span style="font-family:Verdana;">Septic shock is a rapidly changing and fatal syndrome that can </span><span style="font-family:Verdana;">cause comprehensive deterioration of cardiopulmonary and renal function and multiple organ failure. At the same time, septic shock has the complex clinical manifestations and hemodynamics. PiCCO can accurately </span><span style="font-family:Verdana;">monitor blood flow, physical and volume indicators, and active and effective fluid resuscitation are important measures to reduce the fatality rate of septic shock and improve the prognosis of patients. </span><b><span style="font-family:Verdana;">Objectives: </span></b><span style="font-family:Verdana;">To explore the application an</span><span style="font-family:Verdana;">d nursing of PiCCO in early fluid resuscitation in patie</span><span style="font-family:Verdana;">nts with septic shock. </span><b><span style="font-family:Verdana;">Me</span><span style="font-family:Verdana;">thods:</span></b><span style="font-family:Verdana;"> This was a retrospective observ</span><span style="font-family:Verdana;">ational study. The observation group and the control group each had 30 cases. The observation group used PiCCO to guide fluid resuscitation;the control group used conventional methods to guide fluid resuscitation.</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">The changes in CVP, HR, MAP, and urine volume per hour were observed in the two groups. The changes of various indicators before and after fluid resuscitation, the length of stay in ICU and the mortality rate were compared between the two groups. All the outcomes were collected from the electronic medical case system after patients’ discharge from the hospital. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">APACHE </span></span><span style="font-family:Verdana;">II</span><span style="font-family:;" "=""><span style="font-family:Verdana;">, CVP, HR, MAP were compared between th</span><span style="font-family:Verdana;">e obse</span><span style="font-family:Verdana;">rvation group and th</span></span><span style="font-family:;" "=""><span style="font-family:Verdana;">e control group, and the differences w</span><span><span style="font-family:Verdana;">ere statistically significant (</span><i><span style="font-family:Verdana;">P</span></i></span></span><i><span style="font-family:;" "=""> </span></i><span style="font-family:Verdana;"><</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">0.05). The blood volume of patients in the observatio</span><span style="font-family:;" "=""><span style="font-family:Verdana;">n group was significantly improved after fluid supplementation</span><span><span style="font-family:Verdana;"> (</span><i><span style="font-family:Verdana;">P</span></i></span></span><i><span style="font-family:;" "=""> </span></i><span style="font-family:Verdana;"><</span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">0.05). Compared with the control group, the length of stay in ICU in the observation group was significantly shorter, and the mortality rate was also significantly reduced</span><span style="font-family:Verdana;"> (</span><i><span style="font-family:Verdana;">P</span></i></span><span> </span><span style="font-family:Verdana;"><</span><span> </span><span style="font-family:Verdana;">0.05</span><span><span style="font-family:Verdana;">). </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> PiCCO can be better used in early fluid resuscitation of patients with septic shock.</span></span>展开更多
The research presented here is focused on the vibration condition of a small volume solder solder ball,which is placed on the surface of a soldering pad and is exerted a pulse modulated continuous wave laser heat sour...The research presented here is focused on the vibration condition of a small volume solder solder ball,which is placed on the surface of a soldering pad and is exerted a pulse modulated continuous wave laser heat source. Finite element method is applied to analyzed the temperature field in the solder ball, and experi- ment is conducted to test the vibration. the results show that,that, the temperature field flucturates with the same frequency as that of the laser pulse, which in turn causes a forced vibration of the same frequency in the liquid solder ball.展开更多
基金supported by Fund of the National Natural Science Foundation of China (Grant No. 52375553)。
文摘High-overload shocks are very likely to cause damage to the microstructure of MEMS devices, especially the continuous multiple high-overload shocks generated by the penetration of the multilayer target environment pose more stringent challenges to its protective structure. In this study, the kinetic response model of the protective structure under single-pulse and continuous double-pulse impact is established,and a continuous double-pulse high overload impact test impact platform based on the sleeve-type bullet is constructed, and the protective performance of the multi-layer structure under multi-pulse is analyzed based on the acceleration decay ratio, and the results show that the protective performance of the structure has a positive correlation with its thickness, and it is not sensitive to the change of the load of the first impact;the first impact under double-pulse impact will cause damage to the microstructure through the superposition of the second impact. The first impact under double-pulse impact will cause an increase in the overload amplitude of the second impact through superposition;compared with the single-layer structure, the acceleration attenuation ratio of the double-layer structure can be increased by up to 26.13%, among which the epoxy-polyurethane combination has the best protection performance, with an acceleration attenuation ratio of up to 44.68%. This work provides a robust theoretical foundation and experimental basis for the reliable operation of MEMS devices, as well as for the design of protective structures in extreme environments.
文摘BACKGROUND:Pulse indicated continuous cardiac output(PiCCO)has largely replaced Swan-Ganz catheterization in shock patients.However,whether PiCCO monitoring can improve outcomes of shock patients,such as mortality,length of hospital stay,duration of mechanical ventilation,or laboratory parameters,remains unknown.METHODS:This retrospective cohort study included patients with shock in the intensive care unit(ICU)from January 2013 to January 2020.Patients were divided into PiCCO group and non-PiCCO group based on treatment with PiCCO monitoring or not.Demographic characteristics,Acute Physiology and Chronic Health Evaluation(APACHE)II scores,quick Sequential Organ Failure Assessment(qSOFA)scores,14-day mortality,and N-terminal pro-B-type natriuretic peptide(NT-proBNP)levels at 0,1,3 and 7 days after onset of shock,duration of mechanical ventilation,length of hospital stay and hospitalization costs were compiled and analyzed using propensity score matching(PSM).RESULTS:Real-world analysis of 1,583 ICU patients suff ering shock after propensity score matching revealed that 14-day mortality did not differ between PiCCO and non-PiCCO groups(36.2%vs.32.6%,P=0.343).Duration of mechanical ventilation,hospital stay,and hospitalization costs were also similar between the two groups(P>0.05).No diff erences in changes of NT-proBNP levels on days 0,1,3,and 7 as compared to baseline were noted between the two groups(P>0.05).CONCLUSIONS:The results of our real-world indicate that PiCCO monitoring may not shorten the duration of mechanical ventilation,length of hospital stay,or reduce hospitalization costs,nor will it bring survival benefi ts to ICU patients suff ering shock.
基金supported by Beijing Municipal Natural Science Foundation of China(Grant No. 3123036)Science and Technology Project of Beijing Municipal Education Commission of China(Grant No.KM200911417010)
文摘The current research on pulse continuously variable transmission（CVT） is mainly focused on reducing the pulse degree and making pulse degrees a constant value. Current research mainly confined to find out new design parameters by using the method of optimization, and reduce the pulse degree of pulse CVT and its range of variation. But the fact is that the reduction of the pulse degree is not significant. This article presents a new structure of mechanical pulse CVT--the rotational swashplate pulse CVT with driven by helical gear axial meshing. This transmission is simple and compact in structure and low in pulsatile rate （it adopts 6 guide rods）, and the pulsatile degree is irrelevant to the transmission ratio. Theoretically, pulsatile rate could be reduced to zero if appropriate curved surface of the swashplate is used. Compared with the connecting rod pulse CVT, the present struc^tre uses helical gear mechanism as transmission part and it avoids unbalanced inertial force in the former model. This paper analyzes the principle of driving of this transmission, presents its mechanical structure, and discusses its motion characteristics. Experimental prototype of this type of CVT has been manufactured. Tests for the transmission efficiency（when the rotational speed of the output shaft is the maximum） and the angular velocity of the output shaft have been carried out, and data have been analyzed. The experimental results show that the speed of the output shaft for the experimental prototype is slightly lower than the theoretical value, and the transmission efficiency of the experimental prototype is about 70%. The pulse degree of the CVT discussed in this paper is less than the existing pulse CVT of other types, and it is irrelevant to the transmission ratio of the CVT. The research provides the new idea to the CVT study.
文摘<strong>Background</strong><strong>:</strong><b><span style="font-family:;" "=""> </span></b><span style="font-family:;" "=""><span style="font-family:Verdana;">Septic shock is a rapidly changing and fatal syndrome that can </span><span style="font-family:Verdana;">cause comprehensive deterioration of cardiopulmonary and renal function and multiple organ failure. At the same time, septic shock has the complex clinical manifestations and hemodynamics. PiCCO can accurately </span><span style="font-family:Verdana;">monitor blood flow, physical and volume indicators, and active and effective fluid resuscitation are important measures to reduce the fatality rate of septic shock and improve the prognosis of patients. </span><b><span style="font-family:Verdana;">Objectives: </span></b><span style="font-family:Verdana;">To explore the application an</span><span style="font-family:Verdana;">d nursing of PiCCO in early fluid resuscitation in patie</span><span style="font-family:Verdana;">nts with septic shock. </span><b><span style="font-family:Verdana;">Me</span><span style="font-family:Verdana;">thods:</span></b><span style="font-family:Verdana;"> This was a retrospective observ</span><span style="font-family:Verdana;">ational study. The observation group and the control group each had 30 cases. The observation group used PiCCO to guide fluid resuscitation;the control group used conventional methods to guide fluid resuscitation.</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">The changes in CVP, HR, MAP, and urine volume per hour were observed in the two groups. The changes of various indicators before and after fluid resuscitation, the length of stay in ICU and the mortality rate were compared between the two groups. All the outcomes were collected from the electronic medical case system after patients’ discharge from the hospital. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">APACHE </span></span><span style="font-family:Verdana;">II</span><span style="font-family:;" "=""><span style="font-family:Verdana;">, CVP, HR, MAP were compared between th</span><span style="font-family:Verdana;">e obse</span><span style="font-family:Verdana;">rvation group and th</span></span><span style="font-family:;" "=""><span style="font-family:Verdana;">e control group, and the differences w</span><span><span style="font-family:Verdana;">ere statistically significant (</span><i><span style="font-family:Verdana;">P</span></i></span></span><i><span style="font-family:;" "=""> </span></i><span style="font-family:Verdana;"><</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">0.05). The blood volume of patients in the observatio</span><span style="font-family:;" "=""><span style="font-family:Verdana;">n group was significantly improved after fluid supplementation</span><span><span style="font-family:Verdana;"> (</span><i><span style="font-family:Verdana;">P</span></i></span></span><i><span style="font-family:;" "=""> </span></i><span style="font-family:Verdana;"><</span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">0.05). Compared with the control group, the length of stay in ICU in the observation group was significantly shorter, and the mortality rate was also significantly reduced</span><span style="font-family:Verdana;"> (</span><i><span style="font-family:Verdana;">P</span></i></span><span> </span><span style="font-family:Verdana;"><</span><span> </span><span style="font-family:Verdana;">0.05</span><span><span style="font-family:Verdana;">). </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> PiCCO can be better used in early fluid resuscitation of patients with septic shock.</span></span>
文摘The research presented here is focused on the vibration condition of a small volume solder solder ball,which is placed on the surface of a soldering pad and is exerted a pulse modulated continuous wave laser heat source. Finite element method is applied to analyzed the temperature field in the solder ball, and experi- ment is conducted to test the vibration. the results show that,that, the temperature field flucturates with the same frequency as that of the laser pulse, which in turn causes a forced vibration of the same frequency in the liquid solder ball.
