The grindability of alloy Ti6AI4V with zireonia alumina and silicon carbide flap wheels, and the effect of process parameters on grinding forces, grinding temperature and surface integrity are studied. The grinding fo...The grindability of alloy Ti6AI4V with zireonia alumina and silicon carbide flap wheels, and the effect of process parameters on grinding forces, grinding temperature and surface integrity are studied. The grinding forces are measured by KISTLER 9265B dynamometer. The grinding temperature response is obtained by NI USB-621X signal collection system. Ground surface morphology and the metallographic structure are observed by the Hirox KN-7700 stereoscopic microcope and the Quanta200 scanning electron microscope （SEM）. Surface roughnesses are measured by Mahr Perthometer M1 instrument. The surface microhardnesses are detected by HXS-1000 microhardness tester.展开更多
Flapping characteristics of the self-excited flapping motion of submerged vertical turbulent jet in narrow channels are studied theoretically and experimentally.It is found that the water depth is a most important par...Flapping characteristics of the self-excited flapping motion of submerged vertical turbulent jet in narrow channels are studied theoretically and experimentally.It is found that the water depth is a most important parameter to the critical jet exit velocity and the jet flapping frequency.The results indicate that the critical jet exit velocity increases with water depth and the jet flapping frequency is inversely proportional to the water depth.Meanwhile,experimental result also shows that the surface disturbance wave changes the frequency of flapping motion,i.e.the flapping frequency locks-in the disturbing frequency when the disturbing frequency is near and less than the natural flapping frequency.展开更多
The effect of Gurney flaps with different heights on the S809 airfoil and NH1500 blade is numerically simulated.The influence of the Gurney flap is analyzed at different wind speeds and the comparison of the aerodynam...The effect of Gurney flaps with different heights on the S809 airfoil and NH1500 blade is numerically simulated.The influence of the Gurney flap is analyzed at different wind speeds and the comparison of the aerodynamic performance is given between the blades with and without the Gurney flap.The results demonstrate that a Gurney flap added on the blade can greatly increase the efficiency of the wind turbine especially at high wind speeds.展开更多
Objective To assess clinical effectiveness of using bilateral pectoralis major or plus rectus abdominis muscle flaps in treating deep sternal wound infection(DSWI) following median sternotomy. Methods Between January ...Objective To assess clinical effectiveness of using bilateral pectoralis major or plus rectus abdominis muscle flaps in treating deep sternal wound infection(DSWI) following median sternotomy. Methods Between January 2009 and December 2013, 19 patients with DSWI after median sternotomy for cardiac surgery were admitted to our hospital, including 14 males(73.7%) and 5 females(26.3%), aged 55±13(18-78) years. According to the Pairolero classification of infected median sternotomies, 3(15.8%) patients were type II, and the other 16(84.2%) were type III. Surgical procedure consisted of adequate debridement of infected sternum, costal cartilage, granulation, steel wires, suture residues and other foreign substances. Sternal reconstruction used the bilateral pectoralis major or plus rectus abdominis muscle flaps to obliterate dead space. The drainage tubes were placed and connected to a negative pressure generator for adequate drainage. Results There were no intraoperative deaths. In 15 patients(78.9%), bilateral pectoral muscle flaps were mobilized sufficiently to cover and stabilize the defect created by wound debridement. 4 patients(21.0%) needed bilateral pectoral muscle flaps plus rectus abdominis muscle flaps because their pectoralis major muscle flaps could not reach the lowest portion of the wound. 2 patients(10.5%) presented with subcutaneous infection, and 3 patients(15.8%) had hematoma. They recovered following local debridement and medication. 17 patients(89.5%) were examined at follow-up 12 months later, all healed and having stable sternum. No patients showed infection recurrence during the follow-up period over 12 months. Conclusion DSWI following median sternotomy may be effectively managed with adequate debridement of infected tissues and reconstruction with bilateral pectoralis major muscle or plus rectus abdominis muscle flap transposition.展开更多
In this paper, we conducted a numerical analysis on the bottom-hinged flap-type Wave Energy Convertor (WEC). The basic model, implemented through the study using ANSYS-AQWA, has been validated by a three-dimensional p...In this paper, we conducted a numerical analysis on the bottom-hinged flap-type Wave Energy Convertor (WEC). The basic model, implemented through the study using ANSYS-AQWA, has been validated by a three-dimensional physical model of a pitching vertical cylinder. Then, a systematic parametric assessment has been performed on stiffness, damping, and WEC direction against an incoming wave rose, resulting in an optimized flap-type WEC for a specific spot in the Persian Gulf. Here, stiffness is tuned to have a near-resonance condition considering the wave rose, while damping is modified to capture the highest energy for each device direction. Moreover, such sets of specifications have been checked at different directions to present the best combination of stiffness, damping, and device heading. It has been shown that for a real condition, including different wave heights, periods, and directions, it is very important to implement the methodology introduced here to guarantee device performance.展开更多
A bi-objective optimization problem for flapping airfoils is solved to maximize the time-averaged thrust coefficient and the propulsive efficiency. Design variables include the plunging amplitude, the pitching amplitu...A bi-objective optimization problem for flapping airfoils is solved to maximize the time-averaged thrust coefficient and the propulsive efficiency. Design variables include the plunging amplitude, the pitching amplitude and the phase shift angle. A well defined Kriging model is used to substitute the time-consuming high fidelity model, and a multi-objective genetic algorithm is employed as the search algorithm. The optimization results show that the propulsive efficiency can be improved by reducing the plunging amplitude and the phase shift angle in a proper way. The results of global sensitivity analysis using the Sobol’s method show that both of the time-averaged thrust coefficient and the propulsive efficiency are most sensitive to the plunging amplitude, and second most sensitive to the pitching amplitude. It is also observed that the phase shift angle has an un-negligible influence on the propulsive efficiency, and has little effect on the time-averaged thrust coefficient.展开更多
To study the effect of a progressive surface wave on the flapping motion of a vertical turbulent plane jet in shallow water,the laser visualizations and measurements were carried out in a water tank.The images of visu...To study the effect of a progressive surface wave on the flapping motion of a vertical turbulent plane jet in shallow water,the laser visualizations and measurements were carried out in a water tank.The images of visualization by laser-induced fluorescence(LIF)technique show that the jet flapping motion occurs in the wave environ-ment.Using the wave height gauge and laser Doppler velocimetry(LDV) ,experimental results show that the jet flapping motions indeed lock-in to the wave oscillations if the wave frequency is close to but lower than the nature frequency of jet flapping motion.The phenomenon does not occur when the wave frequency is above the nature frequency of jet flapping motion.展开更多
Background:Soft tissue reconstruction is typically conducted after evacuation from theater of operations.If circumstances do not allow timely evacuation,however,defect site may need to be reconstructed in the combat z...Background:Soft tissue reconstruction is typically conducted after evacuation from theater of operations.If circumstances do not allow timely evacuation,however,defect site may need to be reconstructed in the combat zone.Case presentation:A total of 41 patients with extremity soft tissue defect were treated using pedicled flaps by a single orthopedic surgeon during four deployments in Chad,Afghanistan and Mali between 2010 and 2017.The mean age was 25.6 years.A total of 46 injury sites in extremities required flap coverage:19 combat-related injuries(CRIs)and 27 non-combat related injuries(NCRIs).Twenty of the injury sites were infected.Overall,63 pedicled flap transfers were carried out:15 muscle flaps,35 local fasciocutaneous flaps and 13 distant fasciocutaneous flaps.The flap types used did not differ for CRIs or NCRIs.Mean follow-up was 71 days.Complications included deep infection(n=6),flap failure(n=1)and partial flap necrosis(n=1).Limb salvage rate was 92.7%(38/41).Conclusions:Soft tissue defect can be managed with simple pedicled flaps in theatre of operations if needed.Basic reconstructive procedures should be part of the training for military orthopedic surgeons.Trial registration:Retrospectively registered in January 2019(2019-0901-001).展开更多
A female patient at the age of 17 received dilator implant on the right part of her face to prepare skin flap for her facial scar.The skin flap was in good conditions before scar cutting,but showed poor blood circulat...A female patient at the age of 17 received dilator implant on the right part of her face to prepare skin flap for her facial scar.The skin flap was in good conditions before scar cutting,but showed poor blood circulation after being transferred.Hyperbaric oxygen therapy was given at 0.2 MPa(2ATA) in double pure oxygen cabins for 90 min every day for 10 d.The skin flap showed in sound viability and sound blood circulation after the treatment.Hyperbaric oxygen therapy can be used to treat blood circulation disorder in transferred skin flap.展开更多
Given the uncertainty of parameters and the random nature of disturbances that effect a ships course, a robust course controller should be designed on the basis of rudder/flap vector control. This paper analyzes syste...Given the uncertainty of parameters and the random nature of disturbances that effect a ships course, a robust course controller should be designed on the basis of rudder/flap vector control. This paper analyzes system uncertainty, and the choice of weighting functions is also discussed. When sea waves operate on a ship, the energy-concentrating frequency varies with the angle of encounter. For different angles of encounter, different weighting functions are designed. For the pole of a nominal model existing in an imaginary axis, the bilinear-transform method is used. The "2-Riccati" equation is adopted to solve the H∞ controller. A system simulation is given, and the results show that, compared with a PID controller, this system has higher course precision and more robust performance. This research has significant engineering value.展开更多
Objective:To introduce the experiences in the application of island myocutaneous flap for challenging wound on cervico-thoracic region. Methods: Different myocutaneous flaps were selected according to the location, pe...Objective:To introduce the experiences in the application of island myocutaneous flap for challenging wound on cervico-thoracic region. Methods: Different myocutaneous flaps were selected according to the location, peculiarity and etiological factor of wound. There were 28 cases of island pectoralis major island myocutanuous flaps, 34 cases of latissimus dorsi island myocutaneous flaps, 19 cases of trapizius island myocutaneous flaps and 17 cases of rectus abdominis island myocutaneous flaps in this report. Results: All 98 patients with challenging wound on cervico-thoracic region were successfully treated with this method without complications, and obtained functional and cosmetic effectiveness. Conclusion:Challenging wounds in cervico-nuchal region can be repaired with pertoralis major island myocutaneous flap, latissimus dorsi island myocutaneous flap and trapizius island myocutaneous flap, while challenging wounds in thoracic region can be repaired with latissimus dorsi island myocutaneous flap and rectus abdominis island myocutaneous flap. Satisfactory functional and cosmetic results can be obtained.展开更多
Thirty feet of Chinese adult cadavers were dissected under an operativemicroscope to observe the extensor hallucis brevis and extensor digitorum brevisand their vessels and nerves in order to design myocutaneous flaps...Thirty feet of Chinese adult cadavers were dissected under an operativemicroscope to observe the extensor hallucis brevis and extensor digitorum brevisand their vessels and nerves in order to design myocutaneous flaps.It was be-lieved that the lateral tarsal artery and the lateral branch of the deep peronealnerve are the best choice to be included in the pedicle when muscle flaps ormyocutaneous flaps are to be obtained from the dorsum of foot.The size of themuscles may be enlarged both laterally and medially as the clinicalcondition requires.展开更多
Surgical treatment of tongue tumors usually results in a tongue defect half or more thanhalf of its original size which not only interferes with speech, swallow and mastication functions butalso creates contour deform...Surgical treatment of tongue tumors usually results in a tongue defect half or more thanhalf of its original size which not only interferes with speech, swallow and mastication functions butalso creates contour deformity and induces mental suffering In order to restore the contour and func-tions of the tongue 21 cases of tongue defects were repaired and reconstructed with forearm radialor ulnar cutaneous or myocutaneous flaps All the transplanted flaps survived and the restored con-tour and functions were satisfactory. The surgical procedure of tongue reconstruction was intro-duced and how to have a satisfactory recovery of the tongue functions and raise the rate of successof the operation were discussed.展开更多
Diepithelialized tissue flap(DTF)with vascular anastomosis was de-signed in August 1987,and was used for the repair of 12 cases of large intraoraltissue defect.All the operations were successful.The clinical data were...Diepithelialized tissue flap(DTF)with vascular anastomosis was de-signed in August 1987,and was used for the repair of 12 cases of large intraoraltissue defect.All the operations were successful.The clinical data were reportedand the procedure to incise and transplant a DTF described.When the healingprocess and changes of DTF after transplantation were observed,it was foundthat a layer of new smooth epidermis was formed on the surface of the DTF.Theorigin of this new epidermis was discussed.Ten out of the 12 cases have been fol-lowed up for from half a year to 2 and a half years,and the results weresatisfactory.The new epidermis showed no hair growth and the patients did nothave any rough feeling,which usually occurred after ordinary skin grafting.It isbelieved that DTF transplantation is likely an ideal method for the repair andreconstruction of intraoral soft tissue defect.Its disadvantage was that the DTFcontracted severely after healing.Finally the authors put forward the problemsconcerning the transplantation of DTF,which should be investigated further.展开更多
An outdoor flapping wing micro air vehicle （FWMAV） should be able to withstand unpredictable perturbations in the flight condition. The responses of the time-averaged thrust coefficient and the propulsive efficiency...An outdoor flapping wing micro air vehicle （FWMAV） should be able to withstand unpredictable perturbations in the flight condition. The responses of the time-averaged thrust coefficient and the propulsive efficiency with respect to a stochastic flight velocity deviation were numerically investigated. The deviation was assumed to obey the Gauss distribution with a mean value of zero and a specified standard deviation. The probability distributions of the flapping performances were quantified by the non-intrusive polynomial chaos method. It was observed that both of the time-averaged thrust coefficient and the propulsive efficiency obeyed Gauss-like but not the exact Gauss distribution. The velocity deviation had a large effect on the time-averaged thrust coefficient and a small effect on the propulsive efficiency.展开更多
In this paper,the y-component of magnetic field line curvature in the plasma sheet was analyzed,and two kinds of shear structures of the flapping current sheet were found,i.e.symmetric and antisymmetric.The alternatin...In this paper,the y-component of magnetic field line curvature in the plasma sheet was analyzed,and two kinds of shear structures of the flapping current sheet were found,i.e.symmetric and antisymmetric.The alternating bending orientations of the guiding field are exactly corresponding to alternating north-south asymmetries of the bouncing ion population in the sheet center.Those alternating asymmetric plasma sources consequently induce the current sheet flapping motion as a driver.In addition,a substantial particle population with downward motion was observed in the center of a bifurcated current sheet.This population is identified as the quasi-adiabatic particles,and provides a net current opposite to the conventional cross-tail current.展开更多
基金Supported by the Natural Science Foundation of Jiangsu Province (BK2006723)New Century Ex-cellent Talents in University from Ministry of Education of China (NCET-07-0435)~~
文摘The grindability of alloy Ti6AI4V with zireonia alumina and silicon carbide flap wheels, and the effect of process parameters on grinding forces, grinding temperature and surface integrity are studied. The grinding forces are measured by KISTLER 9265B dynamometer. The grinding temperature response is obtained by NI USB-621X signal collection system. Ground surface morphology and the metallographic structure are observed by the Hirox KN-7700 stereoscopic microcope and the Quanta200 scanning electron microscope （SEM）. Surface roughnesses are measured by Mahr Perthometer M1 instrument. The surface microhardnesses are detected by HXS-1000 microhardness tester.
基金Supported by the National Natural Science Foundation of China(10472046)
文摘Flapping characteristics of the self-excited flapping motion of submerged vertical turbulent jet in narrow channels are studied theoretically and experimentally.It is found that the water depth is a most important parameter to the critical jet exit velocity and the jet flapping frequency.The results indicate that the critical jet exit velocity increases with water depth and the jet flapping frequency is inversely proportional to the water depth.Meanwhile,experimental result also shows that the surface disturbance wave changes the frequency of flapping motion,i.e.the flapping frequency locks-in the disturbing frequency when the disturbing frequency is near and less than the natural flapping frequency.
基金Supported by the National Natural Science Foundation of China(11172135)the National Basic Research Program of China(″973″Program)(2014CB046200)the Fundamental Research Funds for the Central Universities(NS2012036,NJ20130008)
文摘The effect of Gurney flaps with different heights on the S809 airfoil and NH1500 blade is numerically simulated.The influence of the Gurney flap is analyzed at different wind speeds and the comparison of the aerodynamic performance is given between the blades with and without the Gurney flap.The results demonstrate that a Gurney flap added on the blade can greatly increase the efficiency of the wind turbine especially at high wind speeds.
文摘Objective To assess clinical effectiveness of using bilateral pectoralis major or plus rectus abdominis muscle flaps in treating deep sternal wound infection(DSWI) following median sternotomy. Methods Between January 2009 and December 2013, 19 patients with DSWI after median sternotomy for cardiac surgery were admitted to our hospital, including 14 males(73.7%) and 5 females(26.3%), aged 55±13(18-78) years. According to the Pairolero classification of infected median sternotomies, 3(15.8%) patients were type II, and the other 16(84.2%) were type III. Surgical procedure consisted of adequate debridement of infected sternum, costal cartilage, granulation, steel wires, suture residues and other foreign substances. Sternal reconstruction used the bilateral pectoralis major or plus rectus abdominis muscle flaps to obliterate dead space. The drainage tubes were placed and connected to a negative pressure generator for adequate drainage. Results There were no intraoperative deaths. In 15 patients(78.9%), bilateral pectoral muscle flaps were mobilized sufficiently to cover and stabilize the defect created by wound debridement. 4 patients(21.0%) needed bilateral pectoral muscle flaps plus rectus abdominis muscle flaps because their pectoralis major muscle flaps could not reach the lowest portion of the wound. 2 patients(10.5%) presented with subcutaneous infection, and 3 patients(15.8%) had hematoma. They recovered following local debridement and medication. 17 patients(89.5%) were examined at follow-up 12 months later, all healed and having stable sternum. No patients showed infection recurrence during the follow-up period over 12 months. Conclusion DSWI following median sternotomy may be effectively managed with adequate debridement of infected tissues and reconstruction with bilateral pectoralis major muscle or plus rectus abdominis muscle flap transposition.
文摘In this paper, we conducted a numerical analysis on the bottom-hinged flap-type Wave Energy Convertor (WEC). The basic model, implemented through the study using ANSYS-AQWA, has been validated by a three-dimensional physical model of a pitching vertical cylinder. Then, a systematic parametric assessment has been performed on stiffness, damping, and WEC direction against an incoming wave rose, resulting in an optimized flap-type WEC for a specific spot in the Persian Gulf. Here, stiffness is tuned to have a near-resonance condition considering the wave rose, while damping is modified to capture the highest energy for each device direction. Moreover, such sets of specifications have been checked at different directions to present the best combination of stiffness, damping, and device heading. It has been shown that for a real condition, including different wave heights, periods, and directions, it is very important to implement the methodology introduced here to guarantee device performance.
基金Supported by the National Science Foundation for Post-doctoral Scientists of China (20090460216 )the National Defense Fundamental Research Foundation of China(B222006060)
文摘A bi-objective optimization problem for flapping airfoils is solved to maximize the time-averaged thrust coefficient and the propulsive efficiency. Design variables include the plunging amplitude, the pitching amplitude and the phase shift angle. A well defined Kriging model is used to substitute the time-consuming high fidelity model, and a multi-objective genetic algorithm is employed as the search algorithm. The optimization results show that the propulsive efficiency can be improved by reducing the plunging amplitude and the phase shift angle in a proper way. The results of global sensitivity analysis using the Sobol’s method show that both of the time-averaged thrust coefficient and the propulsive efficiency are most sensitive to the plunging amplitude, and second most sensitive to the pitching amplitude. It is also observed that the phase shift angle has an un-negligible influence on the propulsive efficiency, and has little effect on the time-averaged thrust coefficient.
文摘To study the effect of a progressive surface wave on the flapping motion of a vertical turbulent plane jet in shallow water,the laser visualizations and measurements were carried out in a water tank.The images of visualization by laser-induced fluorescence(LIF)technique show that the jet flapping motion occurs in the wave environ-ment.Using the wave height gauge and laser Doppler velocimetry(LDV) ,experimental results show that the jet flapping motions indeed lock-in to the wave oscillations if the wave frequency is close to but lower than the nature frequency of jet flapping motion.The phenomenon does not occur when the wave frequency is above the nature frequency of jet flapping motion.
文摘Background:Soft tissue reconstruction is typically conducted after evacuation from theater of operations.If circumstances do not allow timely evacuation,however,defect site may need to be reconstructed in the combat zone.Case presentation:A total of 41 patients with extremity soft tissue defect were treated using pedicled flaps by a single orthopedic surgeon during four deployments in Chad,Afghanistan and Mali between 2010 and 2017.The mean age was 25.6 years.A total of 46 injury sites in extremities required flap coverage:19 combat-related injuries(CRIs)and 27 non-combat related injuries(NCRIs).Twenty of the injury sites were infected.Overall,63 pedicled flap transfers were carried out:15 muscle flaps,35 local fasciocutaneous flaps and 13 distant fasciocutaneous flaps.The flap types used did not differ for CRIs or NCRIs.Mean follow-up was 71 days.Complications included deep infection(n=6),flap failure(n=1)and partial flap necrosis(n=1).Limb salvage rate was 92.7%(38/41).Conclusions:Soft tissue defect can be managed with simple pedicled flaps in theatre of operations if needed.Basic reconstructive procedures should be part of the training for military orthopedic surgeons.Trial registration:Retrospectively registered in January 2019(2019-0901-001).
文摘A female patient at the age of 17 received dilator implant on the right part of her face to prepare skin flap for her facial scar.The skin flap was in good conditions before scar cutting,but showed poor blood circulation after being transferred.Hyperbaric oxygen therapy was given at 0.2 MPa(2ATA) in double pure oxygen cabins for 90 min every day for 10 d.The skin flap showed in sound viability and sound blood circulation after the treatment.Hyperbaric oxygen therapy can be used to treat blood circulation disorder in transferred skin flap.
文摘Given the uncertainty of parameters and the random nature of disturbances that effect a ships course, a robust course controller should be designed on the basis of rudder/flap vector control. This paper analyzes system uncertainty, and the choice of weighting functions is also discussed. When sea waves operate on a ship, the energy-concentrating frequency varies with the angle of encounter. For different angles of encounter, different weighting functions are designed. For the pole of a nominal model existing in an imaginary axis, the bilinear-transform method is used. The "2-Riccati" equation is adopted to solve the H∞ controller. A system simulation is given, and the results show that, compared with a PID controller, this system has higher course precision and more robust performance. This research has significant engineering value.
文摘Objective:To introduce the experiences in the application of island myocutaneous flap for challenging wound on cervico-thoracic region. Methods: Different myocutaneous flaps were selected according to the location, peculiarity and etiological factor of wound. There were 28 cases of island pectoralis major island myocutanuous flaps, 34 cases of latissimus dorsi island myocutaneous flaps, 19 cases of trapizius island myocutaneous flaps and 17 cases of rectus abdominis island myocutaneous flaps in this report. Results: All 98 patients with challenging wound on cervico-thoracic region were successfully treated with this method without complications, and obtained functional and cosmetic effectiveness. Conclusion:Challenging wounds in cervico-nuchal region can be repaired with pertoralis major island myocutaneous flap, latissimus dorsi island myocutaneous flap and trapizius island myocutaneous flap, while challenging wounds in thoracic region can be repaired with latissimus dorsi island myocutaneous flap and rectus abdominis island myocutaneous flap. Satisfactory functional and cosmetic results can be obtained.
文摘Thirty feet of Chinese adult cadavers were dissected under an operativemicroscope to observe the extensor hallucis brevis and extensor digitorum brevisand their vessels and nerves in order to design myocutaneous flaps.It was be-lieved that the lateral tarsal artery and the lateral branch of the deep peronealnerve are the best choice to be included in the pedicle when muscle flaps ormyocutaneous flaps are to be obtained from the dorsum of foot.The size of themuscles may be enlarged both laterally and medially as the clinicalcondition requires.
文摘Surgical treatment of tongue tumors usually results in a tongue defect half or more thanhalf of its original size which not only interferes with speech, swallow and mastication functions butalso creates contour deformity and induces mental suffering In order to restore the contour and func-tions of the tongue 21 cases of tongue defects were repaired and reconstructed with forearm radialor ulnar cutaneous or myocutaneous flaps All the transplanted flaps survived and the restored con-tour and functions were satisfactory. The surgical procedure of tongue reconstruction was intro-duced and how to have a satisfactory recovery of the tongue functions and raise the rate of successof the operation were discussed.
文摘Diepithelialized tissue flap(DTF)with vascular anastomosis was de-signed in August 1987,and was used for the repair of 12 cases of large intraoraltissue defect.All the operations were successful.The clinical data were reportedand the procedure to incise and transplant a DTF described.When the healingprocess and changes of DTF after transplantation were observed,it was foundthat a layer of new smooth epidermis was formed on the surface of the DTF.Theorigin of this new epidermis was discussed.Ten out of the 12 cases have been fol-lowed up for from half a year to 2 and a half years,and the results weresatisfactory.The new epidermis showed no hair growth and the patients did nothave any rough feeling,which usually occurred after ordinary skin grafting.It isbelieved that DTF transplantation is likely an ideal method for the repair andreconstruction of intraoral soft tissue defect.Its disadvantage was that the DTFcontracted severely after healing.Finally the authors put forward the problemsconcerning the transplantation of DTF,which should be investigated further.
基金Supported by the National Natural Science Foundation of China(10972034)the National Science Foundation for Postdoctoral Scientists of China(20090460216)the National Defense Fundamental Research Foundation of China(B222006060)
文摘An outdoor flapping wing micro air vehicle （FWMAV） should be able to withstand unpredictable perturbations in the flight condition. The responses of the time-averaged thrust coefficient and the propulsive efficiency with respect to a stochastic flight velocity deviation were numerically investigated. The deviation was assumed to obey the Gauss distribution with a mean value of zero and a specified standard deviation. The probability distributions of the flapping performances were quantified by the non-intrusive polynomial chaos method. It was observed that both of the time-averaged thrust coefficient and the propulsive efficiency obeyed Gauss-like but not the exact Gauss distribution. The velocity deviation had a large effect on the time-averaged thrust coefficient and a small effect on the propulsive efficiency.
基金the National Natural Science Foundation of China(41174144,40974098)。
文摘In this paper,the y-component of magnetic field line curvature in the plasma sheet was analyzed,and two kinds of shear structures of the flapping current sheet were found,i.e.symmetric and antisymmetric.The alternating bending orientations of the guiding field are exactly corresponding to alternating north-south asymmetries of the bouncing ion population in the sheet center.Those alternating asymmetric plasma sources consequently induce the current sheet flapping motion as a driver.In addition,a substantial particle population with downward motion was observed in the center of a bifurcated current sheet.This population is identified as the quasi-adiabatic particles,and provides a net current opposite to the conventional cross-tail current.
