Background:The worldwide pest Aphis gossypii has three-winged morphs in its life cycle,namely,winged parthenogenetic female(WPF),winged gynopara(GP),and winged male,which are all produced by a wingless parthenogenetic...Background:The worldwide pest Aphis gossypii has three-winged morphs in its life cycle,namely,winged parthenogenetic female(WPF),winged gynopara(GP),and winged male,which are all produced by a wingless parthenogenetic female(WLPF).Most studies on A.gossypii have focused on WPF,while few have investigated GP and male.The shared molecular mechanism underlying the wing differentiation in the three wing morphs of A.gossypii remains unknown.The wing differentiation of WPF was explored in a previous study.Herein,GP and male were induced indoors.The characters of the body,internal genitals,wing veins,and fecundity of GP and male were compared with those of WPF or WLPF.Compared with WLPF,the shared and separate differentially expressed genes(DEGs)were identified in these three-wing morphs.Results:Newly-born nymphs reared in short photoperiod condition(8 L:16D,18°C)exclusively produced gynoparae(GPe)and males in adulthood successively,in which the sex ratio was GP biased.A total of 14 GPe and 9 males were produced by one mother aphid.Compared with WLPF,the three-wing morphs exhibited similar morphology and wing vein patterns but were obviously discriminated in the length of fore-and underwings,reproductive system,and fecundity.A total of 37090 annotated unigenes were obtained from libraries constructed using the four morphs via RNA sequencing(RNA-Seq).In addition,10867 and 19334 DEGs were identified in the pairwise comparison of GP versus WLPF and male versus WLPF,respectively.Compared with WLPF,the winged morphs demonstrated 2335 shared DEGs(1658 upregulated and 677 downregulated).The 1658 shared upregulated DEGs were enriched in multiple signaling pathways,including insulin,FoxO,MAPK,starch and sucrose metabolism,fatty acid biosynthesis,and degradation,suggesting their key roles in the regulation of wing plasticity in the cotton aphid.Forty-four genes that spanned the range of differential expression were chosen to validate statistical analysis based on RNA-Seq through the reverse transcription quantitative real time polymerase chain reaction(RT-qPCR).The comparison concurred with the expression pattern(either up-or downregulated)and supported the accuracy and reliability of RNA-Seq.Finally,the potential roles of DEGs related to the insulin signaling pathway in wing dimorphism were discussed in the cotton aphid.Conclusions:The present study established an efficiently standardized protocol for GP and male induction in cotton aphid by transferring newly-born nymphs to short photoperiod conditions(8 L:16D,18°C).The external morphological characters,especially wing vein patterns,were similar among WPFs,GPe,and males.However,their reproductive organs were strikingly different.Compared with WLPF,shared(2335)and exclusively(1470 in WLPF,2419 in GP,10774 male)expressed genes were identified in the three-wing morphs through RNA-Seq,and several signaling pathways that are potentially involved in their wing differentiation were obtained,including insulin signaling,starch and sucrose metabolism.展开更多
By considering the effect of hydraulic pressure filled in wing crack and the connected part of main crack on the stress intensity factor at wing crack tip, a new wing crack model exerted by hydraulic pressure and far ...By considering the effect of hydraulic pressure filled in wing crack and the connected part of main crack on the stress intensity factor at wing crack tip, a new wing crack model exerted by hydraulic pressure and far field stresses was proposed. By introducing the equivalent crack length lcq of wing crack, two terms make up the stress intensity factor K1 at wing crack tip： one is the component K（1） for a single isolated straight wing crack of length 2l subjected to hydraulic pressure in wing crack and far field stresses, and the other is the component K1^（2） due to the effective shear stress induced by the presence of the equivalent main crack. The FEM model of wing crack propagation subjected to hydraulic pressure and far field stresses was also established according to different side pressure coefficients and hydraulic pressures in crack. The result shows that a good agreement is found between theoretical model of wing crack proposed and finite element method （FEM）. In theory, an unstable crack propagation is shown if there is high hydraulic pressure and lateral tension. The wing crack model proposed can provide references for studying on hydraulic fracturing in rock masses.展开更多
Background:Aphis gossypii is a worldwide sap-sucking pest with a variety of hosts and a vector of more than 50 plant viruses.The strategy of wing polyphenism,mostly resulting from population density increasing,contrib...Background:Aphis gossypii is a worldwide sap-sucking pest with a variety of hosts and a vector of more than 50 plant viruses.The strategy of wing polyphenism,mostly resulting from population density increasing,contributes to the evolutionary success of this pest.However,the related molecular basis remains unclear.Here,we identified the effects of postnatal crowding on wing morph determination in cotton aphid,and examined the transcriptomic differences between wingless and wing morphs.Results:Effect of postnatal crowding on wing determination in A gossypii was evaluated firstly.Under the density of 5 nymphs·cm-2,no wing aphids appeared.Proportion of wing morphs rised with the increase of density in a certain extent,and peaked to 56.1% at the density of 20 nymphs·cm-2,and reduced afterwards.Then,transcriptomes of wingless and wing morphs were assembled and annotated separately to identify potentially exclusively or differentially expressed transcripts between these two morphs,in which 3 126 and 3 392 unigenes annotated in Nr(Non-redundant protein sequence) database were found in wingless or wing morphs exclusively.Moreover,3 187 up-and 1 880 down-regulated genes were identified in wing versus wingless aphid.Pathways analysis suggested the involvement of differentially expressed genes in multiple cellular signaling pathways involved in wing morphs determination,including lipid catabolic and metabolism,insulin,ecdysone and juvenile hormone biosynthesis.The expression levels of related genes were validated by the reverse transcription quantitative real time polymerase chain reaction(RT-qPCR) soon afterwards.Conclusions:The present study identified the effects of postnatal crowding on wing morphs induction and demonstrated that the critical population density for wing morphs formation in A gossypii was 20 nymphs·cm-2.Comparative transcriptome analysis provides transcripts potentially expressed exclusively in wingless or wing morph,respectively.Differentially expressed genes between wingless and wing morphs were identified and several signaling pathways potentially involved in cotton aphid wing differentiation were obtained.展开更多
Damage assessment of the wing under blast wave is essential to the vulnerability reduction design of aircraft. This paper introduces a critical relative distance prediction method of aircraft wing damage based on the ...Damage assessment of the wing under blast wave is essential to the vulnerability reduction design of aircraft. This paper introduces a critical relative distance prediction method of aircraft wing damage based on the back-propagation artificial neural network(BP-ANN), which is trained by finite element simulation results. Moreover, the finite element method(FEM) for wing blast damage simulation has been validated by ground explosion tests and further used for damage mode determination and damage characteristics analysis. The analysis results indicate that the wing is more likely to be damaged when the root is struck from vertical directions than others for a small charge. With the increase of TNT equivalent charge, the main damage mode of the wing gradually changes from the local skin tearing to overall structural deformation and the overpressure threshold of wing damage decreases rapidly. Compared to the FEM-based damage assessment, the BP-ANN-based method can predict the wing damage under a random blast wave with an average relative error of 4.78%. The proposed method and conclusions can be used as a reference for damage assessment under blast wave and low-vulnerability design of aircraft structures.展开更多
Inflatable wing has significant application value in the design of loitering munitions because of its advantages such as lightweight and foldability.However,due to the flexible characteristics,aeroelastic behaviors of...Inflatable wing has significant application value in the design of loitering munitions because of its advantages such as lightweight and foldability.However,due to the flexible characteristics,aeroelastic behaviors of inflatable wings such as flutter are nonnegligible in flight.By designing a certain angle between the inflatable beam and the wing span,the structural dynamic and even the aeroelastic performance of the inflatable wing can be effectively improved.Based on the analysis of the mechanical and geometric characteristics of the inflatable structure,a new inflatable wing with sweep arranged inflatable beams is proposed,and the main design variables and methods are analyzed.For purpose of investigating the aeroelastic performance of the swept baffled inflatable wing,the modal behaviors by considering the wet mode are studied.In consideration of the deficiencies of the traditional wet modal analysis method,by introducing the influence on the additional stiffness of flow field,an added massstiffness method is proposed in this paper,and the advantages are verified by ground vibration experiments.On this basis,the effects of baffles sweep angle,pressure,and boundary conditions on the modal parameters and aeroelastic performance of inflatable wing are analyzed.The results show that the aeroelastic performance of the inflatable wing can be designed by changing the baffles sweep angle,which is enlightened for the aeroelastic tailoring design on inflatable wings.展开更多
In the present research,by using a numerical model,some analyses were performed on flows around a T-shape spur dike and a support structure located at its upstream under different wing to length ratios of T-shape spur...In the present research,by using a numerical model,some analyses were performed on flows around a T-shape spur dike and a support structure located at its upstream under different wing to length ratios of T-shape spur dike in the order of 0.25,0.50,0.75 and 1.00.In order to verify numerical model,physical model data were used in presence of a single T shape spur dike.Results from numerical model are desirably in agreement with those of physical one because the regression between both data is 0.86 up to 0.92.In this research,all hydraulic parameters of flows,streamlines and dimensions of flow separation zones were studied in order to select the most practical model.Increased W/L results in 7%–12%increase in the length of flow separation zone and in 2%increase in the width of this zone compared to W/L=0.25.展开更多
A blank panel design algorithm based on feature mapping methods for integral wing skin panels with supercritical airfoil surface is presented.The model of a wing panel is decomposed into features,and features of the p...A blank panel design algorithm based on feature mapping methods for integral wing skin panels with supercritical airfoil surface is presented.The model of a wing panel is decomposed into features,and features of the panel are decomposed into information of location,direction,dimension and Boolean types.Features are mapped into the plane through optimal surface development algorithm.The plane panel is modeled by rebuilding the mapped features.Blanks of shot-peen forming panels are designed to identify the effectiveness of the methods.展开更多
An efficient design method is proposed for the cooperative control problem of morphing wing systems with distributed structures and bounded control inputs. The multi-agent model of the distributed morphing wing system...An efficient design method is proposed for the cooperative control problem of morphing wing systems with distributed structures and bounded control inputs. The multi-agent model of the distributed morphing wing system is established. The cooperative controllers with saturation constraints are presented. By introducing the concepts in consensus algorithms, the cooperative information links in the controllers are described by graphs, and the corresponding Laplacian matrix is defined. The design conditions of the cooperative controllers are proposed, in the form of linear matrix inequalities. For the case of undirected information links, the controller design conditions are simplified as algebraic inequalities, which highly reduce the computation cost. The designed controllers are implemented on a distributed morphing wing platform, and experiments are carried out. Simulation and experiment results show that the controllers can make all the actuating units in the morphing wing system cooperatively achieve the desired positions, which demonstrates the effectiveness of the proposed theory.展开更多
Background:Aphis gossypii Glover(Hemiptera:Aphididae),a worldwide polyphagous phloem-feeding agricultural pest,has three wing morphs(winged parthenogenetic female,gynopara,and male)in the life cycle.The exclusive male...Background:Aphis gossypii Glover(Hemiptera:Aphididae),a worldwide polyphagous phloem-feeding agricultural pest,has three wing morphs(winged parthenogenetic female,gynopara,and male)in the life cycle.The exclusive males could fly from summer hosts to winter hosts,which are essential for gene exchanges of cotton aphid populations from different hosts or regions.However,the molecular mechanism of wing differentiation of male in A.gossypii remains unclear.Results:Morphological observation of male A.gossypii showed that there is no distinct difference in the external morphologies of the 1st and 2nd instar nymphs.The obvious differentiation of wing buds started in the 3rd instar nymph and was visible via naked eyes in the 4th instar nymphal stage,then adult male emerged with full wings.According to morphological dynamic changes,the development of wings in males were divided into four stages:preliminary stage(the 1st instar to 2nd instar),prophase(the 3rd instar),metaphase(the 4th instar),anaphase(the 5th instar).Results of feeding behavior monitoring via EPG(electrical penetration graph)technology indicated that although the male cotton aphids had strong desire to feed(longer duration of C 55.24%,F 5.05%and Pd waves 2.56%),its feeding efficiency to summer host cotton was low(shorter E13.56%and E2 waves 2.63%).Dynamic transcriptome analysis of male aphid at 5 different developmental periods showed that in the 3rd instar nymph,the number of up-regulated DEGs was significant increased,and time-course gene transcriptional pattern analyses results also showed that numerous genes categorized in clusters 3,5,and 8 had the highest expressed levels,which were consistent with morphological changes of wing buds.These results indicate that the 3rd instar nymph is the critical stage of wing bud differentiation in males.Furthermore,through pathway enrichment analysis of DEGs and WGCNA,it revealed that the neuroactive ligand-receptor interaction,Ras signaling pathway,dopaminergic synapse,circadian entrainment and the corresponding hub genes of PLK1,BUB1,SMC2,TUBG,ASPM,the kinesin family members(KIF23,KIF20,KIF18-19)and the novel subfamily of serine/threonine(Aurora kinase A and Aurora kinase B)probably played an important role in the critical stage of wing bud differentiation.Conclusion:This study explored morphological changes and genes transcriptional dynamics males in cotton aphid,revealed the phenomenon of low feeding efficiency of winged males on summer host cotton,and identified key signaling pathways and potential hub genes potentially involved in wing bud differentiation of male in A.gossypii.展开更多
Micro Aerial Vehicles(MAVs) are the smallest artificial aircraft.Most of the flapping wings MAVs are powered by electric motors of various capacities.We report in this paper the application of piezoelectric actuators ...Micro Aerial Vehicles(MAVs) are the smallest artificial aircraft.Most of the flapping wings MAVs are powered by electric motors of various capacities.We report in this paper the application of piezoelectric actuators as power system for a flapping wing MAV using a compliant displacement amplification mechanism.The actuator used for this application is a pre-stressed cut piece of TH-7R type Thunder actuator.A two-bar compliant mechanism with two flexures has been developed to convert the linear displacement into angular movement and amplification.The specimens were made from carbon fiber links and nylon flexures.We also proposed to use the product of frequency(F) and tip displacement(D), F * D as a criteria for the characterization of an amplifying mechanism.The best specimen according to this criterion is obtained for a 5mm length flexure specimen made of three layers of nylon.The F*D value obtained for this specimen was(0.58) Hz.m.ANSYS finite element analysis results for different flexural thickness and lengths were obtained and have been compared to the experimental results.The effect of both the thickness and length of the flexure on a particular arrangement has been discussed.展开更多
The design of unmanned aerial vehicles(UAVs)revolves around the careful selection of materials that are both lightweight and robust.Carbon fiber-reinforced polymer(CFRP)emerged as an ideal option for wing construction...The design of unmanned aerial vehicles(UAVs)revolves around the careful selection of materials that are both lightweight and robust.Carbon fiber-reinforced polymer(CFRP)emerged as an ideal option for wing construction,with its mechanical qualities thoroughly investigated.In this study,we developed and optimized a conceptual UAV wing to withstand structural loads by establishing progressive composite stacking sequences,and we conducted a series of experimental characterizations on the resulting material.In the optimization phase,the objective was defined as weight reduction,while the Hashin damage criterion was established as the constraint for the optimization process.The optimization algorithm adaptively monitors regional damage criterion values,implementing necessary adjustments to facilitate the mitigation process in a cost-effective manner.Optimization of the analytical model using Simulia Abaqus~(TM)and a Python-based user-defined sub-routine resulted in a 34.7%reduction in the wing's structural weight after 45 iterative rounds.Then,the custom-developed optimization algorithm was compared with a genetic algorithm optimization.This comparison has demonstrated that,although the genetic algorithm explores numerous possibilities through hybridization,the custom-developed algorithm is more result-oriented and achieves optimization in a reduced number of steps.To validate the structural analysis,test specimens were fabricated from the wing's most critically loaded segment,utilizing the identical stacking sequence employed in the optimization studies.Rigorous mechanical testing revealed unexpectedly high compressive strength,while tensile and bending strengths fell within expected ranges.All observed failure loads remained within the established safety margins,thereby confirming the reliability of the analytical predictions.展开更多
基金Central Public-interest Scientific Institution Basal Research Fund(No.1610162019020604).
文摘Background:The worldwide pest Aphis gossypii has three-winged morphs in its life cycle,namely,winged parthenogenetic female(WPF),winged gynopara(GP),and winged male,which are all produced by a wingless parthenogenetic female(WLPF).Most studies on A.gossypii have focused on WPF,while few have investigated GP and male.The shared molecular mechanism underlying the wing differentiation in the three wing morphs of A.gossypii remains unknown.The wing differentiation of WPF was explored in a previous study.Herein,GP and male were induced indoors.The characters of the body,internal genitals,wing veins,and fecundity of GP and male were compared with those of WPF or WLPF.Compared with WLPF,the shared and separate differentially expressed genes(DEGs)were identified in these three-wing morphs.Results:Newly-born nymphs reared in short photoperiod condition(8 L:16D,18°C)exclusively produced gynoparae(GPe)and males in adulthood successively,in which the sex ratio was GP biased.A total of 14 GPe and 9 males were produced by one mother aphid.Compared with WLPF,the three-wing morphs exhibited similar morphology and wing vein patterns but were obviously discriminated in the length of fore-and underwings,reproductive system,and fecundity.A total of 37090 annotated unigenes were obtained from libraries constructed using the four morphs via RNA sequencing(RNA-Seq).In addition,10867 and 19334 DEGs were identified in the pairwise comparison of GP versus WLPF and male versus WLPF,respectively.Compared with WLPF,the winged morphs demonstrated 2335 shared DEGs(1658 upregulated and 677 downregulated).The 1658 shared upregulated DEGs were enriched in multiple signaling pathways,including insulin,FoxO,MAPK,starch and sucrose metabolism,fatty acid biosynthesis,and degradation,suggesting their key roles in the regulation of wing plasticity in the cotton aphid.Forty-four genes that spanned the range of differential expression were chosen to validate statistical analysis based on RNA-Seq through the reverse transcription quantitative real time polymerase chain reaction(RT-qPCR).The comparison concurred with the expression pattern(either up-or downregulated)and supported the accuracy and reliability of RNA-Seq.Finally,the potential roles of DEGs related to the insulin signaling pathway in wing dimorphism were discussed in the cotton aphid.Conclusions:The present study established an efficiently standardized protocol for GP and male induction in cotton aphid by transferring newly-born nymphs to short photoperiod conditions(8 L:16D,18°C).The external morphological characters,especially wing vein patterns,were similar among WPFs,GPe,and males.However,their reproductive organs were strikingly different.Compared with WLPF,shared(2335)and exclusively(1470 in WLPF,2419 in GP,10774 male)expressed genes were identified in the three-wing morphs through RNA-Seq,and several signaling pathways that are potentially involved in their wing differentiation were obtained,including insulin signaling,starch and sucrose metabolism.
基金Projects(10972238,51074071,50974059)supported by the National Natural Science Foundation of ChinaProject(10JJ3007)supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project(11C0539)supported by Scientific Research Fund of Hunan Provincial Education Department,ChinaProject(200905)supported by Open Research Fund of Hunan Provincial Key of Safe Mining Techniques of Coal Mines,China
文摘By considering the effect of hydraulic pressure filled in wing crack and the connected part of main crack on the stress intensity factor at wing crack tip, a new wing crack model exerted by hydraulic pressure and far field stresses was proposed. By introducing the equivalent crack length lcq of wing crack, two terms make up the stress intensity factor K1 at wing crack tip： one is the component K（1） for a single isolated straight wing crack of length 2l subjected to hydraulic pressure in wing crack and far field stresses, and the other is the component K1^（2） due to the effective shear stress induced by the presence of the equivalent main crack. The FEM model of wing crack propagation subjected to hydraulic pressure and far field stresses was also established according to different side pressure coefficients and hydraulic pressures in crack. The result shows that a good agreement is found between theoretical model of wing crack proposed and finite element method （FEM）. In theory, an unstable crack propagation is shown if there is high hydraulic pressure and lateral tension. The wing crack model proposed can provide references for studying on hydraulic fracturing in rock masses.
基金funded by National Natural Science Foundation of China(No.31572015)
文摘Background:Aphis gossypii is a worldwide sap-sucking pest with a variety of hosts and a vector of more than 50 plant viruses.The strategy of wing polyphenism,mostly resulting from population density increasing,contributes to the evolutionary success of this pest.However,the related molecular basis remains unclear.Here,we identified the effects of postnatal crowding on wing morph determination in cotton aphid,and examined the transcriptomic differences between wingless and wing morphs.Results:Effect of postnatal crowding on wing determination in A gossypii was evaluated firstly.Under the density of 5 nymphs·cm-2,no wing aphids appeared.Proportion of wing morphs rised with the increase of density in a certain extent,and peaked to 56.1% at the density of 20 nymphs·cm-2,and reduced afterwards.Then,transcriptomes of wingless and wing morphs were assembled and annotated separately to identify potentially exclusively or differentially expressed transcripts between these two morphs,in which 3 126 and 3 392 unigenes annotated in Nr(Non-redundant protein sequence) database were found in wingless or wing morphs exclusively.Moreover,3 187 up-and 1 880 down-regulated genes were identified in wing versus wingless aphid.Pathways analysis suggested the involvement of differentially expressed genes in multiple cellular signaling pathways involved in wing morphs determination,including lipid catabolic and metabolism,insulin,ecdysone and juvenile hormone biosynthesis.The expression levels of related genes were validated by the reverse transcription quantitative real time polymerase chain reaction(RT-qPCR) soon afterwards.Conclusions:The present study identified the effects of postnatal crowding on wing morphs induction and demonstrated that the critical population density for wing morphs formation in A gossypii was 20 nymphs·cm-2.Comparative transcriptome analysis provides transcripts potentially expressed exclusively in wingless or wing morph,respectively.Differentially expressed genes between wingless and wing morphs were identified and several signaling pathways potentially involved in cotton aphid wing differentiation were obtained.
基金supported by the Natural Science Foundation of Shaanxi Province (Grant No. 2020JQ-122)the Fund support of Science and Technology on Transient Impact Laboratory。
文摘Damage assessment of the wing under blast wave is essential to the vulnerability reduction design of aircraft. This paper introduces a critical relative distance prediction method of aircraft wing damage based on the back-propagation artificial neural network(BP-ANN), which is trained by finite element simulation results. Moreover, the finite element method(FEM) for wing blast damage simulation has been validated by ground explosion tests and further used for damage mode determination and damage characteristics analysis. The analysis results indicate that the wing is more likely to be damaged when the root is struck from vertical directions than others for a small charge. With the increase of TNT equivalent charge, the main damage mode of the wing gradually changes from the local skin tearing to overall structural deformation and the overpressure threshold of wing damage decreases rapidly. Compared to the FEM-based damage assessment, the BP-ANN-based method can predict the wing damage under a random blast wave with an average relative error of 4.78%. The proposed method and conclusions can be used as a reference for damage assessment under blast wave and low-vulnerability design of aircraft structures.
基金supported by National Natural Science Foundation of China(Grant No.11902029)。
文摘Inflatable wing has significant application value in the design of loitering munitions because of its advantages such as lightweight and foldability.However,due to the flexible characteristics,aeroelastic behaviors of inflatable wings such as flutter are nonnegligible in flight.By designing a certain angle between the inflatable beam and the wing span,the structural dynamic and even the aeroelastic performance of the inflatable wing can be effectively improved.Based on the analysis of the mechanical and geometric characteristics of the inflatable structure,a new inflatable wing with sweep arranged inflatable beams is proposed,and the main design variables and methods are analyzed.For purpose of investigating the aeroelastic performance of the swept baffled inflatable wing,the modal behaviors by considering the wet mode are studied.In consideration of the deficiencies of the traditional wet modal analysis method,by introducing the influence on the additional stiffness of flow field,an added massstiffness method is proposed in this paper,and the advantages are verified by ground vibration experiments.On this basis,the effects of baffles sweep angle,pressure,and boundary conditions on the modal parameters and aeroelastic performance of inflatable wing are analyzed.The results show that the aeroelastic performance of the inflatable wing can be designed by changing the baffles sweep angle,which is enlightened for the aeroelastic tailoring design on inflatable wings.
文摘In the present research,by using a numerical model,some analyses were performed on flows around a T-shape spur dike and a support structure located at its upstream under different wing to length ratios of T-shape spur dike in the order of 0.25,0.50,0.75 and 1.00.In order to verify numerical model,physical model data were used in presence of a single T shape spur dike.Results from numerical model are desirably in agreement with those of physical one because the regression between both data is 0.86 up to 0.92.In this research,all hydraulic parameters of flows,streamlines and dimensions of flow separation zones were studied in order to select the most practical model.Increased W/L results in 7%–12%increase in the length of flow separation zone and in 2%increase in the width of this zone compared to W/L=0.25.
文摘A blank panel design algorithm based on feature mapping methods for integral wing skin panels with supercritical airfoil surface is presented.The model of a wing panel is decomposed into features,and features of the panel are decomposed into information of location,direction,dimension and Boolean types.Features are mapped into the plane through optimal surface development algorithm.The plane panel is modeled by rebuilding the mapped features.Blanks of shot-peen forming panels are designed to identify the effectiveness of the methods.
基金supported by the National Natural Science Foundation of China (90605007 91016017)
文摘An efficient design method is proposed for the cooperative control problem of morphing wing systems with distributed structures and bounded control inputs. The multi-agent model of the distributed morphing wing system is established. The cooperative controllers with saturation constraints are presented. By introducing the concepts in consensus algorithms, the cooperative information links in the controllers are described by graphs, and the corresponding Laplacian matrix is defined. The design conditions of the cooperative controllers are proposed, in the form of linear matrix inequalities. For the case of undirected information links, the controller design conditions are simplified as algebraic inequalities, which highly reduce the computation cost. The designed controllers are implemented on a distributed morphing wing platform, and experiments are carried out. Simulation and experiment results show that the controllers can make all the actuating units in the morphing wing system cooperatively achieve the desired positions, which demonstrates the effectiveness of the proposed theory.
基金funded by National Natural Science Foundation of China(No.32102214)Special Fund for Basic Public Welfare Research of Institute of Cotton Research of CAAS(No.1610162020020604).
文摘Background:Aphis gossypii Glover(Hemiptera:Aphididae),a worldwide polyphagous phloem-feeding agricultural pest,has three wing morphs(winged parthenogenetic female,gynopara,and male)in the life cycle.The exclusive males could fly from summer hosts to winter hosts,which are essential for gene exchanges of cotton aphid populations from different hosts or regions.However,the molecular mechanism of wing differentiation of male in A.gossypii remains unclear.Results:Morphological observation of male A.gossypii showed that there is no distinct difference in the external morphologies of the 1st and 2nd instar nymphs.The obvious differentiation of wing buds started in the 3rd instar nymph and was visible via naked eyes in the 4th instar nymphal stage,then adult male emerged with full wings.According to morphological dynamic changes,the development of wings in males were divided into four stages:preliminary stage(the 1st instar to 2nd instar),prophase(the 3rd instar),metaphase(the 4th instar),anaphase(the 5th instar).Results of feeding behavior monitoring via EPG(electrical penetration graph)technology indicated that although the male cotton aphids had strong desire to feed(longer duration of C 55.24%,F 5.05%and Pd waves 2.56%),its feeding efficiency to summer host cotton was low(shorter E13.56%and E2 waves 2.63%).Dynamic transcriptome analysis of male aphid at 5 different developmental periods showed that in the 3rd instar nymph,the number of up-regulated DEGs was significant increased,and time-course gene transcriptional pattern analyses results also showed that numerous genes categorized in clusters 3,5,and 8 had the highest expressed levels,which were consistent with morphological changes of wing buds.These results indicate that the 3rd instar nymph is the critical stage of wing bud differentiation in males.Furthermore,through pathway enrichment analysis of DEGs and WGCNA,it revealed that the neuroactive ligand-receptor interaction,Ras signaling pathway,dopaminergic synapse,circadian entrainment and the corresponding hub genes of PLK1,BUB1,SMC2,TUBG,ASPM,the kinesin family members(KIF23,KIF20,KIF18-19)and the novel subfamily of serine/threonine(Aurora kinase A and Aurora kinase B)probably played an important role in the critical stage of wing bud differentiation.Conclusion:This study explored morphological changes and genes transcriptional dynamics males in cotton aphid,revealed the phenomenon of low feeding efficiency of winged males on summer host cotton,and identified key signaling pathways and potential hub genes potentially involved in wing bud differentiation of male in A.gossypii.
文摘Micro Aerial Vehicles(MAVs) are the smallest artificial aircraft.Most of the flapping wings MAVs are powered by electric motors of various capacities.We report in this paper the application of piezoelectric actuators as power system for a flapping wing MAV using a compliant displacement amplification mechanism.The actuator used for this application is a pre-stressed cut piece of TH-7R type Thunder actuator.A two-bar compliant mechanism with two flexures has been developed to convert the linear displacement into angular movement and amplification.The specimens were made from carbon fiber links and nylon flexures.We also proposed to use the product of frequency(F) and tip displacement(D), F * D as a criteria for the characterization of an amplifying mechanism.The best specimen according to this criterion is obtained for a 5mm length flexure specimen made of three layers of nylon.The F*D value obtained for this specimen was(0.58) Hz.m.ANSYS finite element analysis results for different flexural thickness and lengths were obtained and have been compared to the experimental results.The effect of both the thickness and length of the flexure on a particular arrangement has been discussed.
基金supported by the Istanbul Technical University Office of Scientific Research Projects(ITUBAPSIS),under grant MYL-2022-43776。
文摘The design of unmanned aerial vehicles(UAVs)revolves around the careful selection of materials that are both lightweight and robust.Carbon fiber-reinforced polymer(CFRP)emerged as an ideal option for wing construction,with its mechanical qualities thoroughly investigated.In this study,we developed and optimized a conceptual UAV wing to withstand structural loads by establishing progressive composite stacking sequences,and we conducted a series of experimental characterizations on the resulting material.In the optimization phase,the objective was defined as weight reduction,while the Hashin damage criterion was established as the constraint for the optimization process.The optimization algorithm adaptively monitors regional damage criterion values,implementing necessary adjustments to facilitate the mitigation process in a cost-effective manner.Optimization of the analytical model using Simulia Abaqus~(TM)and a Python-based user-defined sub-routine resulted in a 34.7%reduction in the wing's structural weight after 45 iterative rounds.Then,the custom-developed optimization algorithm was compared with a genetic algorithm optimization.This comparison has demonstrated that,although the genetic algorithm explores numerous possibilities through hybridization,the custom-developed algorithm is more result-oriented and achieves optimization in a reduced number of steps.To validate the structural analysis,test specimens were fabricated from the wing's most critically loaded segment,utilizing the identical stacking sequence employed in the optimization studies.Rigorous mechanical testing revealed unexpectedly high compressive strength,while tensile and bending strengths fell within expected ranges.All observed failure loads remained within the established safety margins,thereby confirming the reliability of the analytical predictions.
