检索结果-南通市图书馆

Aerodynamic Interactions Between Wing and Body of a Model Insect in Forward Flight and maneuvers

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2013年第1期10卷 19-27页

作者： Bin Liang Mao Sun Ministry-of-Education Key Laboratory of Fluid Mechanics Beihang University Beoing 100191 P. R. China

The aerodynamic interactions between the body and the wings of a model insect in forward flight and maneuvers are studied using the method of numerically solving the Navier-Stokes equations over moving overset grids. Three cases are con- sidered, including a complete insect, wing pair only and body only. By comparing the results of these cases, the interaction effect between the body and the wing pair can be identified. The changes in the force and moment coefficients of the wing pair due to the presence of the body are less than 4.5% of the mean vertical force coefficient of the model insect; the changes in the aero- dynamic force coefficients of the body due to the presence of the wings are less than 5.0% of the mean vertical force coefficient of the model insect. The results of this paper indicate that in studying the aerodynamics and flight dynamics of a flapping insect in forward flight or maneuver, separately computing （or measuring） the aerodynamic forces and moments on the wing paig and on the body could be a good approximation.

关键词： insect wing-body aerodynamic interaction forward flight maneuvers Navier-Stokes simulation

Respiratory Volume Monitoring to Assess the Effect of Airway maneuvers on Ventilation during Upper Endoscopy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Anesthesiology 2014年第11期4卷 281-290页

作者： Katherine Holley Donald Mathews Diane Ladd Lisa Campana Howard Schapiro Department of Anesthesiology Fletcher Allen Health Care University of Vermont College of Medicine Burlington USA School of Nursing West Virginia University Morgantown USA Respiratory Motion Inc. Waltham USA

Introduction: Propofol use during endoscopic procedures has become increasingly popular and assessing and maintaining airway patency is a significant challenge. Anesthesiologists often use airway maneuvers to maintain airway patency and ventilation during procedural sedation. A novel, non-invasive, Respiratory Volume Monitor (RVM) that provided continuous, real-time measurements of minute ventilation (MV), tidal volume (TV) and respiratory rate (RR) was used to monitor respiratory performance before, during, and after endoscopic procedures, quantify MV changes before and after airway maneuvers, and to quantify propofol-induced respiratory depression. Methods: RVM traces were obtained from 25 patients undergoing sedation for endoscopic procedures. Airway maneuvers were performed in 19/25 patients. All 25 patients received propofol as the primary sedative. Results: Forty-five airway maneuvers were performed. During these maneuvers, all respiratory parameters increased relative to pre-maneuver levels. On average, MV increased by 24% ± 5% (mean ± SEM), TV 14% ± 5% and RR: 17% ± 6%. The cohort average MVBASELINE was 9.5 ± 0.7 L/min (TV = 670 ± 60 ml, RR = 15 ± 0.7). Following propofol MV decreased transiently, reaching nadir five minutes after the last dose of propofol at 82% ± 10% of baseline (MV = 7.5 ± 1.0 L/min). The reduction in MV was driven by reduction in TV, not RR. Conclusions: Data demonstrated that RVM was able to track changes in ventilation and was able to quantify respiratory changes following airway maneuvers. All patients had a significant reduction in ventilatory volumes after propofol. Five minutes after the last dose of propofol, MV and TV were significantly reduced while RR was not, suggesting that monitoring respiratory rate alone was not a sufficient indicator of respiratory status.

关键词： Non-Invasive Respiratory Volume Monitoring Minute Ventilation Airway maneuvers Procedural Sedation Endoscopy

Ventilator management for acute respiratory distress syndrome associated with avian infl uenza A(H7N9) virus infection: A case series

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Emergency Medicine 2018年第2期9卷 118-124页

作者： Hui Xie Zhi-gang Zhou Wei Jin Cheng-bin Yuan Jiang Du Jian Lu Rui-lan Wang Department of Critical Care Medicine Shanghai General Hospital Shanghai Jiaotong University School of Medicine

BACKGROUND: Data on the mechanical ventilation(MV) characteristics and radiologic features for the cases with H7 N9-induced ARDS were still lacking.METHODS: We describe the MV characteristics and radiologic features of adult patients with ARDS due to microbiologically confirmed H7 N9 admitted to our ICU over a 3-month period.RESULTS: Eight patients(mean age 57.38±16.75; 5 male) were diagnosed with H7 N9 in the first quarter of 2014. All developed respiratory failure complicated by acute respiratory distress syndrome(ARDS), which required MV in ICU. The baseline APACHE II and SOFA score was 11.77±6.32 and 7.71±3.12. The overall CT scores of the patients was 247.68±34.28 and the range of CT scores was 196.3–294.7. The average MV days was 14.63±6.14, and 4 patients required additional rescue therapies for refractory hypoxemia. Despite these measures, 3 patients died.CONCLUSION: In H7 N9-infected patients with ARDS, low tidal volume strategy was the conventional mode. RM as one of rescue therapies to refractory hypoxemia in these patients with serious architectural distortion and high CT scores, which could cause further lung damage, may induce bad outcomes and requires serious consideration. Prone ventilation may improve mortality, and should be performed at the early stage of the disease, not as a rescue therapy.

关键词： Acute respiratory distress syndrome Influenza A virus H7N9 Viral pneumonia Mechanical ventilation Recruitment maneuvers Prone positioning

A new digital algorithm for the velocity translation vector

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2013年第8期56卷 237-249页

作者： SONG Min WU WenQi College of Mechatronics Engineering and Automation National University of Defense Technology

The error of the conventional sculling correction algorithm under maneuvers is analyzed through Taylor series expansion;a generalized error equation is presented.Using frequency-series sculling algorithms in the digital algorithm for the velocity translation vector will cause the accuracy of the digital algorithm under maneuvers to decrease by one order in iteration time interval.Some New sculling algorithms are developed and evaluated,which are as accurate as frequency-series sculling algorithms under vibrations,and are at least one order more accurate than frequency-series algorithms under maneuvers.Several new digital algorithms are constructed with the presented sculling algorithms for the velocity translation vector,which avoids the loss in accuracy of velocity translation vector under maneuvers.Simulations agree well with the analytical results.

关键词： sculling correction velocity translation vector maneuvers vibrations digital algorithm error evaluation

ANALYSIS OF DYNAMIC FLOW BEHAVIOR IN PITCHING MANEUVER

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 1996年第4期9卷 247-251页

作者： Chen Nanqian Liu Rizhi Ma Zongjiang(Institute Of Fluid Mechanics, Beijing University Of Aeronauticsand Astronautics, Beijing, China, 100083) Institute of Fluid Mechanics Beijing Univ. Aero. and Astronaut. Beijing 100083 China

The dynamic flow behavior during pitching maneuver is related to the dynamic wash effect induced by the motion of the object. The dynamic hysteresis effect dueto the pivot position moving back is similar to that due to the increase in pitching rate.During the aircraft pitching up, a strong dynamic hysteresis appears on the canard but another dynamic 'advanced' effect occurs on the horizontal tail. So the stall on the canardwould occur at a higher angle of attack but the stall on the tail would appear at a lower an, gle of attack. The dynamic hysteresis is also affected by the 'heredity' effect relating tothe initial conditions besides the dynamic wash effect.

关键词： pitch maneuvers dynamic characteristics dynamic hysteresis

Recruitment maneuvers in acute respiratory distress syndrome: The safe way is the best way

在线全文

学校读者我要写书评

暂无评论

World Journal of Critical Care Medicine 2015年第4期4卷 278-286页

作者： Raquel S Santos Pedro L Silva Paolo Pelosi Patricia RM Rocco Laboratory of Pulmonary Investigation Institute of Biophysics Carlos Chagas Filho Federal University of Rio de Janeiro IRCCS AOU San Martino-IST Department of Surgical Sciences and Integrated Diagnostics University of Genoa

Acute respiratory distress syndrome(ARDS) represents a serious problem in critically ill patients and is associated with in-hospital mortality rates of 33%-52%. Recruitment maneuvers(RMs) are a simple, low-cost, feasible intervention that can be performed at the bedside in patients with ARDS. RMs are characterized by the application of airway pressure to increase transpulmonary pressure transiently. Once non-aerated lung units are reopened, improvements are observed in respiratory system mechanics, alveolar reaeration on computed tomography, and improvements in gas exchange(functional recruitment). However, the reopening process could lead to vascular compression, which can be associated with overinflation, and gas exchange may not improve as expected(anatomical recruitment). The purpose of this review was to discuss the effects of different RM strategies- sustained inflation, intermittent sighs, and stepwise increases of positive end-expiratory pressure(PEEP) and/or airway inspiratory pressure- on the following parameters: hemodynamics, oxygenation, barotrauma episodes, and lung recruitability through physiological variables and imaging techniques. RMs and PEEP titration are interdependent events for the success of ventilatory management. PEEP should be adjusted on the basis of respiratory system mechanics and oxygenation. Recent systematic reviews and meta-analyses suggest that RMs are associated with lower mortality in patients with ARDS. However, the optimal RM method(i.e., that providing the best balance of benefit and harm) and the effects of RMs on clinical outcome are still under discussion, and further evidence is needed.

关键词： Recruitment maneuvers Acute respiratory distress syndrome Positive end-expiratory pressure Transpulmonary pressure Lung ultrasonography

NONLINEAR INVERSE SIMULATION FOR THE MANEUVERING FLIGHT OF COAXIAL ROTOR HELICOPTERS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 1997年第4期10卷 2-9页

作者： Cao Yihua (Institute of Aircraft Design, Beijing University of Aeronautics and Astronautics, Beijing, 100083, China) G. Reichert (Technical University of Braunschweig, 38106 Braunschweig, Germany)

The maneuvering flight governing equations for coaxial rotor helicopters are established. By introducing induced velocity interference factor analysis, the coaxial rotor aerodynamic interference can be taken into account. With the combination of coaxial rotor helicopter control features and nonlinear inverse solution technique, the governing equations for maneuvering flight can be solved so as to determine helicopter control input, control force and moment, and helicopter body attitudes which are needed for performing the defined maneuver. Finally, as an example of this methods engineering application, the calculated results with level turn, lateral jink maneuvers are presented and simply analyzed.

关键词： helicopters rotor aerodynamics maneuvers flight inverse simulation

ANALYTICAL MODEL OF HELICOPTER AIRCOMBAT AND MATHEMATICINVERSE SOLUTION

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 1995年第4期8卷 237-246页

作者： Cao Yihua(Institute of Fluid Mechanics, Beijing University of Aeronauticsand Astronautics, Beijing, China, 100083)

in helicopter air combat, the helicopter must have the maneuverability andagility to gain a firing position first and its weapon systems must be able to get firstround hits for successful air combat. In an attempt to address the questions, a generalanalytical model of helicopter / annament system combat is established. Taking the hel-icopter air combat at short range as an example, the kinematic law of a turreted gun iscalculated. The development and results here may provide a referable basis for maxinuz-ing the hit probability of the gun in air firing.

关键词： helicopters maneuvers flight combat

Airway Characteristics and Safe Management of Spontaneously Breathing Patients: Risks of Sedation and Analgesia and Changes in Wakefulness

在线全文

学校读者我要写书评

暂无评论

International Journal of Clinical Medicine 2016年第11期7卷 726-735页

作者： Adrian Reber Department of Anesthesia and Intensive Care Medicine Hospital of Zollikerberg Zollikerberg Switzerland

The goal of safe airway management is to maintain a patent airway. Lack of knowledge of the anatomical morphology and changes that may occur in the upper airway during sedation and unconsciousness may lead to critical incidents and hazardous complications. This review focuses on the risks of sedation and analgesia and changes in wakefulness on airway patency in spontaneously breathing patients. Furthermore, key elements of airway management are presented and discussed.

关键词： Airway Analgesia Anesthetics Anesthesia Breathing Chin Lift Diagnostics Emergency Jaw Thrust Sedation maneuvers Obesity Obstructive Sleep Apnea Posture Sleep