In order to control the growth of space debris,a novel tethered space robot(TSR) was put forward.After capture,the platform,tether,and target constituted a tethered combination system.General nonlinear dynamics of the...In order to control the growth of space debris,a novel tethered space robot(TSR) was put forward.After capture,the platform,tether,and target constituted a tethered combination system.General nonlinear dynamics of the tethered combination system in the post-capture phase was established with the consideration of the attitudes of two spacecrafts and the quadratic nonlinear elasticity of the tether.The motion law of the tethered combination in the deorbiting process with different disturbances was simulated and discussed on the premise that the platform was only controlled by a constant thrust force.It is known that the four motion freedoms of the tethered combination are coupled with each other in the deorbiting process from the simulation results.A noticeable phenomenon is that the tether longitudinal vibration does not decay to vanish even under the large tether damping with initial attitude disturbances due to the coupling effect.The approximate analytical solutions of the dynamics for a simplified model are obtained through the perturbation method.The condition of the inter resonance phenomenon is the frequency ratio λ_1=2.The case study shows good accordance between the analytical solutions and numerical results,indicating the effectiveness and correctness of approximate analytical solutions.展开更多
Objective： To study the effect and indications ofintracranial pressure （ICP） monitoring for frontal lobe contusion patients. Methods： During January 2005-December 2008, 34 cases of frontal lobe contusion received ...Objective： To study the effect and indications ofintracranial pressure （ICP） monitoring for frontal lobe contusion patients. Methods： During January 2005-December 2008, 34 cases of frontal lobe contusion received ICP monitoring in our department （monitoring group）. Different treatment protocols were adopted according to the results of ICP. Mean-while 46 cases of same type of head-injured patients who did not undergo ICP monitoring served as control group. Results： We found that ICP elevated dramatically within 24 hours after head injury if the contusions were located in frontal longitudinal dehiscence, bilateral undersurface of frontal lobe or dispersed in bilateral lobe. After half a year follow-up and on the basis of Glasgow Coma Scale assessment, the monitoring group showed better outcome than the control group with good recovery in 24 cases （70.6%）, moderate disability in 7 cases （20.6%）, severe disability in 2 （5.88%） and death in 1 （2.94%）. The outcome of control group displayed good condition in 25 cases （54.3%）, moderate disabilities in 8 （17.4%）, severe disability in 7 （15.2%）, and death in 6 （13.0%）. Conclusions： Frontal lobe contusions are vulnerable and complex head injuries, especially when the contusions are located in frontal longitudinal dehiscence, bilateral undersurface of frontal lobe or diffused in bilateral lobes. These patients should undergo ICP monitoring regardless of their consciousness status. IflCP elevates over 25 mm Hg, the craniotomy is mandatory and will markedly reduce the mortality and disability of these patients.展开更多
基金Project (51475411) supported by the National Natural Science Foundation of ChinaProject (LY15E070002) supported by Zhejiang Provincial Natural Science Foundation of China
文摘In order to control the growth of space debris,a novel tethered space robot(TSR) was put forward.After capture,the platform,tether,and target constituted a tethered combination system.General nonlinear dynamics of the tethered combination system in the post-capture phase was established with the consideration of the attitudes of two spacecrafts and the quadratic nonlinear elasticity of the tether.The motion law of the tethered combination in the deorbiting process with different disturbances was simulated and discussed on the premise that the platform was only controlled by a constant thrust force.It is known that the four motion freedoms of the tethered combination are coupled with each other in the deorbiting process from the simulation results.A noticeable phenomenon is that the tether longitudinal vibration does not decay to vanish even under the large tether damping with initial attitude disturbances due to the coupling effect.The approximate analytical solutions of the dynamics for a simplified model are obtained through the perturbation method.The condition of the inter resonance phenomenon is the frequency ratio λ_1=2.The case study shows good accordance between the analytical solutions and numerical results,indicating the effectiveness and correctness of approximate analytical solutions.
文摘Objective： To study the effect and indications ofintracranial pressure （ICP） monitoring for frontal lobe contusion patients. Methods： During January 2005-December 2008, 34 cases of frontal lobe contusion received ICP monitoring in our department （monitoring group）. Different treatment protocols were adopted according to the results of ICP. Mean-while 46 cases of same type of head-injured patients who did not undergo ICP monitoring served as control group. Results： We found that ICP elevated dramatically within 24 hours after head injury if the contusions were located in frontal longitudinal dehiscence, bilateral undersurface of frontal lobe or dispersed in bilateral lobe. After half a year follow-up and on the basis of Glasgow Coma Scale assessment, the monitoring group showed better outcome than the control group with good recovery in 24 cases （70.6%）, moderate disability in 7 cases （20.6%）, severe disability in 2 （5.88%） and death in 1 （2.94%）. The outcome of control group displayed good condition in 25 cases （54.3%）, moderate disabilities in 8 （17.4%）, severe disability in 7 （15.2%）, and death in 6 （13.0%）. Conclusions： Frontal lobe contusions are vulnerable and complex head injuries, especially when the contusions are located in frontal longitudinal dehiscence, bilateral undersurface of frontal lobe or diffused in bilateral lobes. These patients should undergo ICP monitoring regardless of their consciousness status. IflCP elevates over 25 mm Hg, the craniotomy is mandatory and will markedly reduce the mortality and disability of these patients.
