Background Hypoxemia sometimes occurs in the emergency room in the patients with acute myocardial infarction （AMI） after percutaneous coronary intervention （PCI）, even in those with administration of conventional ...Background Hypoxemia sometimes occurs in the emergency room in the patients with acute myocardial infarction （AMI） after percutaneous coronary intervention （PCI）, even in those with administration of conventional high-flow oxygen inhalation. The objective of the present study was to evaluate the effectiveness of non-invasive ventilation （NIV） in improving blood oxygen content and hemorheology in patients with AMI and hypoxemia. Methods This prospective study enrolled 50 consecutive eligible patients with AMI （aged 72.3 ± 9.5 years）, who had undergone PCI and been administered high-flow oxygen but still had hypoxemia. Blood was taken before NIV and at 0.5, 1, and 2 h after NIV. Blood gases, hemorheological variables including erythrocyte deformability, erythrocyte aggregation, erythrocyte osmotic fragility, membrane fluidity, and oxidative stress level were measured. Results Blood PaO2 increased to normal by 1 h after NIV. Assessed hemorheological variables had all improved and plasma malondialdehyde concentration decreased significantly after 2 h of NIV. Conclusions Our data suggest that NIV can help to improve blood oxygen content, hemorheological status, and minimize plasma lipid peroxidation injury in hypoxemic patients with AMI who have undergone PCI.展开更多
In order to optionally regulate embedding capacity and embedding transparency according to user's requirements in voice-over-IP(VoIP) steganography,a dynamic matrix encoding strategy(DMES) was presented.Differing ...In order to optionally regulate embedding capacity and embedding transparency according to user's requirements in voice-over-IP(VoIP) steganography,a dynamic matrix encoding strategy(DMES) was presented.Differing from the traditional matrix encoding strategy,DMES dynamically chose the size of each message group in a given set of adoptable message sizes.The appearance possibilities of all adoptable sizes were set in accordance with the desired embedding performance(embedding rate or bit-change rate).Accordingly,a searching algorithm that could provide an optimal combination of appearance possibilities was proposed.Furthermore,the roulette wheel algorithm was employed to determine the size of each message group according to the optimal combination of appearance possibilities.The effectiveness of DMES was evaluated in StegVoIP,which is a typical covert communication system based on VoIP.The experimental results demonstrate that DMES can adjust embedding capacity and embedding transparency effectively and flexibly,and achieve the desired embedding performance in any case.For the desired embedding rate,the average errors are not more than 0.000 8,and the standard deviations are not more than 0.002 0;for the desired bit-change rate,the average errors are not more than 0.001 4,and the standard deviations are not more than 0.002 6.展开更多
9803544 与运动相关的眼外伤?三年随访研究/Capao Filipe J A// J Am AcadOphthalmol.-1997,104(2).-313～318北医图9803545 外伤对静脉注射的环丙沙星眼透入性的影响/Alfaro D V//Am J Oph-thalmol.-1996,122(5).-678～683四军大98035...9803544 与运动相关的眼外伤?三年随访研究/Capao Filipe J A// J Am AcadOphthalmol.-1997,104(2).-313～318北医图9803545 外伤对静脉注射的环丙沙星眼透入性的影响/Alfaro D V//Am J Oph-thalmol.-1996,122(5).-678～683四军大9803546 穿过结膜进入颧骨眶底骨折/Mangakello Souza L C//Int J Oral Maxitlo-fac Surg.-1997,26(1).-31～34 北医口9803547展开更多
The three-dimensional seepage simulation test device for siltation dam foundation soil is a multifunctional penetration instrument which is designed for the simulation of infiltration clogging,seepage damage,and dam s...The three-dimensional seepage simulation test device for siltation dam foundation soil is a multifunctional penetration instrument which is designed for the simulation of infiltration clogging,seepage damage,and dam seepage and so on. This device is different from the traditional instruments for the rock and soil permeability. In order to verify the practicability of the device,the authors collected the soil samples for laboratory penetration test,observed the seepage damage phenomenon,and obtained the dynamic change curve of permeability coefficient and isopotential map of water pressure. At the same time,the Geostudio finite element software is used to simulate the steady seepage of the test device. By contrast of the isopotential maps between simulation and actual water pressures,it is found that they are approximately the same. It is proved that the test data of the device is scientific and reliable,reaching the results of the test and design purposes. The instrument can be used in many aspects of experimental study on soil seepage.展开更多
Field infiltration measurement is often a tedious task thus can be easily estimated from proposed infiltration models. The Horton equation is one of the popular models used in the characterization of field infiltratio...Field infiltration measurement is often a tedious task thus can be easily estimated from proposed infiltration models. The Horton equation is one of the popular models used in the characterization of field infiltration. In this study, the least square curve firing technique was employed to estimate the model parameters from fifteen field measured data and gave resultant mean regression coefficients （R2） value of 0.811. Furthermore, plotting the measured against the calculated infiltration rate for the first six （6） measurement points yielded R2 values close to unity in the regression curve indicating a marked relationship between the two. This indicates that the Horton infiltration model can be applied to estimate infiltration characteristics of soils in Samaru, Northern Guinea Savanna of Nigeria.展开更多
This paper addresses the composite nonlinear feedback（CNF） control for a class of singleinput single-output nonlinear systems with input saturation to track a time varying reference target with good transient perfor...This paper addresses the composite nonlinear feedback（CNF） control for a class of singleinput single-output nonlinear systems with input saturation to track a time varying reference target with good transient performance. The CNF control law consists of a tracking control law and a performance compensator. The tracking control law is designed to drive the output of the system to track the time varying reference target rapidly, while the performance compensator is used to reduce the overshoot caused by the tracking control law. The stability of the closed-loop system is established. The design procedure and the improvement of transient performance of the closed-loop system are illustrated with a numerical example and the controlled Van del Pol oscillator.展开更多
文摘Background Hypoxemia sometimes occurs in the emergency room in the patients with acute myocardial infarction （AMI） after percutaneous coronary intervention （PCI）, even in those with administration of conventional high-flow oxygen inhalation. The objective of the present study was to evaluate the effectiveness of non-invasive ventilation （NIV） in improving blood oxygen content and hemorheology in patients with AMI and hypoxemia. Methods This prospective study enrolled 50 consecutive eligible patients with AMI （aged 72.3 ± 9.5 years）, who had undergone PCI and been administered high-flow oxygen but still had hypoxemia. Blood was taken before NIV and at 0.5, 1, and 2 h after NIV. Blood gases, hemorheological variables including erythrocyte deformability, erythrocyte aggregation, erythrocyte osmotic fragility, membrane fluidity, and oxidative stress level were measured. Results Blood PaO2 increased to normal by 1 h after NIV. Assessed hemorheological variables had all improved and plasma malondialdehyde concentration decreased significantly after 2 h of NIV. Conclusions Our data suggest that NIV can help to improve blood oxygen content, hemorheological status, and minimize plasma lipid peroxidation injury in hypoxemic patients with AMI who have undergone PCI.
基金Project(2009AA01A402) supported by the National High-Tech Research and Development Program of ChinaProject(NCET-06-0650) supported by Program for New Century Excellent Talents in University Project(IRT-0725) supported by Program for Changjiang Scholars and Innovative Research Team in Chinese University
文摘In order to optionally regulate embedding capacity and embedding transparency according to user's requirements in voice-over-IP(VoIP) steganography,a dynamic matrix encoding strategy(DMES) was presented.Differing from the traditional matrix encoding strategy,DMES dynamically chose the size of each message group in a given set of adoptable message sizes.The appearance possibilities of all adoptable sizes were set in accordance with the desired embedding performance(embedding rate or bit-change rate).Accordingly,a searching algorithm that could provide an optimal combination of appearance possibilities was proposed.Furthermore,the roulette wheel algorithm was employed to determine the size of each message group according to the optimal combination of appearance possibilities.The effectiveness of DMES was evaluated in StegVoIP,which is a typical covert communication system based on VoIP.The experimental results demonstrate that DMES can adjust embedding capacity and embedding transparency effectively and flexibly,and achieve the desired embedding performance in any case.For the desired embedding rate,the average errors are not more than 0.000 8,and the standard deviations are not more than 0.002 0;for the desired bit-change rate,the average errors are not more than 0.001 4,and the standard deviations are not more than 0.002 6.
基金National Natural Science Foundation of China(No.41072197)
文摘The three-dimensional seepage simulation test device for siltation dam foundation soil is a multifunctional penetration instrument which is designed for the simulation of infiltration clogging,seepage damage,and dam seepage and so on. This device is different from the traditional instruments for the rock and soil permeability. In order to verify the practicability of the device,the authors collected the soil samples for laboratory penetration test,observed the seepage damage phenomenon,and obtained the dynamic change curve of permeability coefficient and isopotential map of water pressure. At the same time,the Geostudio finite element software is used to simulate the steady seepage of the test device. By contrast of the isopotential maps between simulation and actual water pressures,it is found that they are approximately the same. It is proved that the test data of the device is scientific and reliable,reaching the results of the test and design purposes. The instrument can be used in many aspects of experimental study on soil seepage.
文摘Field infiltration measurement is often a tedious task thus can be easily estimated from proposed infiltration models. The Horton equation is one of the popular models used in the characterization of field infiltration. In this study, the least square curve firing technique was employed to estimate the model parameters from fifteen field measured data and gave resultant mean regression coefficients （R2） value of 0.811. Furthermore, plotting the measured against the calculated infiltration rate for the first six （6） measurement points yielded R2 values close to unity in the regression curve indicating a marked relationship between the two. This indicates that the Horton infiltration model can be applied to estimate infiltration characteristics of soils in Samaru, Northern Guinea Savanna of Nigeria.
基金supported by the National Nature Science Foundation of China under Grant Nos.61374035 and 61733017
文摘This paper addresses the composite nonlinear feedback（CNF） control for a class of singleinput single-output nonlinear systems with input saturation to track a time varying reference target with good transient performance. The CNF control law consists of a tracking control law and a performance compensator. The tracking control law is designed to drive the output of the system to track the time varying reference target rapidly, while the performance compensator is used to reduce the overshoot caused by the tracking control law. The stability of the closed-loop system is established. The design procedure and the improvement of transient performance of the closed-loop system are illustrated with a numerical example and the controlled Van del Pol oscillator.
