At present, there are some concerns and problems to treat neurointensive care patients by using analgesics and sedatives. Conditions of neurointensive care patients change quickly. For neurointensive care patients who...At present, there are some concerns and problems to treat neurointensive care patients by using analgesics and sedatives. Conditions of neurointensive care patients change quickly. For neurointensive care patients who cannot have auxiliary examination timely, clinicians judge intracranial conditions mainly through relevant monitoring devices and consciousness and pupil changes of patients. The use of analgesics and sedatives is limited due to worry about influences on consciousness evaluation and judgment and different degrees of inhibition on cardiovascular system and respiratory system. Common sedatives (e.g. benzodiazepines) and common analgesics (e.g. morphine, fentanyl and sufentanil) both may inhibit respiration. The specification often provides taboos for the use of drugs by patients with increase intracranial pressure (ICP) and craniocerebral injuries. Through literature review, the author analyzed influences of analgesics and sedatives on ICP of neurointensive care patients comprehensively.展开更多
Despite being one of the oldest and most widely-used turbulence models in engineering computational fluid dynamics(CFD),the k-ωmodel has not been fully understood theoretically because of its high nonlinearity and co...Despite being one of the oldest and most widely-used turbulence models in engineering computational fluid dynamics(CFD),the k-ωmodel has not been fully understood theoretically because of its high nonlinearity and complex model parameter setting.Here,a multi-layer analytic expression is postulated for two lengths(stress and kinetic energy lengths),yielding an analytic solution for the k-ωmodel equations in pipe flow.Approximate local balance equations are analyzed to determine the key parameters in the solution,which are shown to be rather close to the empirically-measured values from the numerical solution of the Wilcox k-ωmodel,and hence the analytic construction is fully validated.The results provide clear evidence that the k-ωmodel sets in it a multilayer structure,which is similar to but different,in some insignificant details,from the Navier-Stokes(N-S)turbulence.This finding explains why the k-ωmodel is so popular,especially in computing the near-wall flow.Finally,the analysis is extended to a newlyrefined k-ωmodel called the structural ensemble dynamics(SED)k-ωmodel,showing that the SED k-ωmodel has improved the multi-layer structure in the outer flow but preserved the setting of the k-ωmodel in the inner region.展开更多
文摘At present, there are some concerns and problems to treat neurointensive care patients by using analgesics and sedatives. Conditions of neurointensive care patients change quickly. For neurointensive care patients who cannot have auxiliary examination timely, clinicians judge intracranial conditions mainly through relevant monitoring devices and consciousness and pupil changes of patients. The use of analgesics and sedatives is limited due to worry about influences on consciousness evaluation and judgment and different degrees of inhibition on cardiovascular system and respiratory system. Common sedatives (e.g. benzodiazepines) and common analgesics (e.g. morphine, fentanyl and sufentanil) both may inhibit respiration. The specification often provides taboos for the use of drugs by patients with increase intracranial pressure (ICP) and craniocerebral injuries. Through literature review, the author analyzed influences of analgesics and sedatives on ICP of neurointensive care patients comprehensively.
基金the National Numerical Wind Tunnel(No.NNW2019ZT1-A03)the National Natural Science Foundation of China(Nos.91952201,11372008,and 11452002)。
文摘Despite being one of the oldest and most widely-used turbulence models in engineering computational fluid dynamics(CFD),the k-ωmodel has not been fully understood theoretically because of its high nonlinearity and complex model parameter setting.Here,a multi-layer analytic expression is postulated for two lengths(stress and kinetic energy lengths),yielding an analytic solution for the k-ωmodel equations in pipe flow.Approximate local balance equations are analyzed to determine the key parameters in the solution,which are shown to be rather close to the empirically-measured values from the numerical solution of the Wilcox k-ωmodel,and hence the analytic construction is fully validated.The results provide clear evidence that the k-ωmodel sets in it a multilayer structure,which is similar to but different,in some insignificant details,from the Navier-Stokes(N-S)turbulence.This finding explains why the k-ωmodel is so popular,especially in computing the near-wall flow.Finally,the analysis is extended to a newlyrefined k-ωmodel called the structural ensemble dynamics(SED)k-ωmodel,showing that the SED k-ωmodel has improved the multi-layer structure in the outer flow but preserved the setting of the k-ωmodel in the inner region.
