The fluid mechanics of water entry is studied through investigating the underwater acoustics and the supercavitation.Underwater acoustic signals in water entry are extensively measured at about 30 different positions ...The fluid mechanics of water entry is studied through investigating the underwater acoustics and the supercavitation.Underwater acoustic signals in water entry are extensively measured at about 30 different positions by using a PVDF needle hydrophone.From the measurements we obtain (1)the primary shock wave caused by the impact of the blunt body on free surface;(2)the vapor pressure inside the cavity;(3)the secondary shock wave caused by pulling away of the cavity from free surface;and so on.The supercavitation induced by the blunt body is observed by using a digital high-speed video camera as well as the single shot photography.The periodic and 3 dimensional motion of the supercavitation is revealed.The experiment is carried out at room temperature.展开更多
When a shock wave interacts with a group of solid spheres,non-linear aerodynamic behaviors come into effect.The complicated wave reflections such as the Mach reflection occur in the wave propagation process.The wave i...When a shock wave interacts with a group of solid spheres,non-linear aerodynamic behaviors come into effect.The complicated wave reflections such as the Mach reflection occur in the wave propagation process.The wave interactions with vortices behind each sphere's wake cause fluctuation in the pressure profiles of shock waves.This paper reports an experimental study for the aerodynamic processes involved in the interaction between shock waves and solid spheres.A schlieren photography was applied to visualize the various shock waves passing through solid spheres.Pressure measurements were performed along different downstream positions.The experiments were conducted in both rectangular and circular shock tubes.The data with respect to the effect of the sphere array, size,interval distance,incident Mach number,etc.,on the shock wave attenuation were obtained.展开更多
In the re-entry phase of a ballistic missile,decoys can be deployed as a mean to overburden enemy defenses.This results in a single track being split into multiple track-lets.Tracking of these track-lets is a critical...In the re-entry phase of a ballistic missile,decoys can be deployed as a mean to overburden enemy defenses.This results in a single track being split into multiple track-lets.Tracking of these track-lets is a critical task as any miss in the tracking procedure can become a cause of a major threat.The tracking process becomes more complicated in the presence of clutter.The low detection rate is one of the factors that may contribute to increasing the difficulty level in terms of tracking in the cluttered environment.This work introduces a new algorithm for the split event detection and target tracking under the framework of the joint integrated probabilistic data association(JIPDA)algorithm.The proposed algorithm is termed as split event-JIPDA(SE-JIPDA).This work establishes the mathematical foundation for the split target detection and tracking mechanism.The performance analysis is made under different simulation conditions to provide a clear insight into the merits of the proposed algorithm.The performance parameters in these simulations are the root mean square error(RMSE),confirmed true track rate(CTTR)and confirmed split true track rate(CSTTR).展开更多
The management of bacterial infections is becoming a major clinical challenge due to the rapid evolution of antibiotic resistant bacteria.As an excellent candidate to overcome antibiotic resistance,antimicrobial pepti...The management of bacterial infections is becoming a major clinical challenge due to the rapid evolution of antibiotic resistant bacteria.As an excellent candidate to overcome antibiotic resistance,antimicrobial peptides(AMPs)that are produced from the synthetic and natural sources demonstrate a broad-spectrum antimicrobial activity with the high specificity and low toxicity.These peptides possess distinctive structures and functions by employing sophisticated mechanisms of action.This comprehensive review provides a broad overview of AMPs from the origin,structural characteristics,mechanisms of action,biological activities to clinical applications.We finally discuss the strategies to optimize and develop AMP-based treatment as the potential antimicrobial and anticancer therapeutics.展开更多
The salt transport in a PEBA membrane used in pervaporative desalination was studied.The concentration profile of salt in the membrane during pervaporation was investigated experimentally using a multilayer membrane.T...The salt transport in a PEBA membrane used in pervaporative desalination was studied.The concentration profile of salt in the membrane during pervaporation was investigated experimentally using a multilayer membrane.The salt was found to be sorbed in the membrane but was not removed during the pervaporative desalination process,and the salt concentration in the membrane varied linearly with position.High purity water was obtained as the permeate as long as the permeate side was kept dry under vacuum.The accumulated salt uptake in the membrane follows the order of MgCl2 N NaCl N Na2 SO4.The solubility of salt in the membrane follows the order of MgCl2 N NaCl N Na2 SO4.Both the permeability and diffusivity of salt in the membrane follow the order of NaCl N MgCl2 N Na2 SO4.The permeability of salt in the membrane is not influenced by the feed salt concentration.It is mainly determined by the diffusion coefficients.展开更多
Poly-lactic acid(PLA) is widely used as a controlled drug release material and the diffusion property of water within the polymer matrix is closely related to the drug release profile. This paper studies the water dif...Poly-lactic acid(PLA) is widely used as a controlled drug release material and the diffusion property of water within the polymer matrix is closely related to the drug release profile. This paper studies the water diffusion in PLA by molecular dynamic simulations. Free volume analysis indicates that water molecules are expected to fill in the free volumes of the polymer matrix forming water clusters at low water content. Along with the increase of the water concentration, the polymer starts to swell and the density of the system starts to drop.Due to the high mobility of water within water cluster, the calculated diffusion coefficient dramatically increases along with the incensement of water content. Thus, we conclude that the diffusion of water is a self-accelerate process, with higher mobility of water in the case where more water exists.展开更多
With 3D orthogonal and pseudo-orthogonal weaves, woven sructures with lengthwise and widthwise changing cross section on one side or both sides of the structure can be constructed. The weave formation and the looming ...With 3D orthogonal and pseudo-orthogonal weaves, woven sructures with lengthwise and widthwise changing cross section on one side or both sides of the structure can be constructed. The weave formation and the looming draft creation are discussed in this paper which can be used as references to manufacture woven preforms with changing cross sections.展开更多
We establish an extension result of existence and partial regularity for the nonzero Neumann initial-boundary value problem of the Landau-Lifshitz equation with nonpositive anisotropy constants in three or four dimens...We establish an extension result of existence and partial regularity for the nonzero Neumann initial-boundary value problem of the Landau-Lifshitz equation with nonpositive anisotropy constants in three or four dimension space. The partial regularity is proved up to the boundary and this result is an important supplement to those for the Dirichlet problem or the homogeneous Neumann problem.展开更多
Medicinal plants are an excellent source of structurally diverse,bio-active compounds with potential in the fight against cancer.One of the most promising is Scutellaria barbata,prescribed traditionally for the treatm...Medicinal plants are an excellent source of structurally diverse,bio-active compounds with potential in the fight against cancer.One of the most promising is Scutellaria barbata,prescribed traditionally for the treatment of cancers.Scutebarbatine A is the major diterpenoid,produced in specialized large,peltate trichomes on leaves of S.barbata.It induces dose-dependent apoptosis,specifically in cancer cells.The major class of proteins down-regulated are pro-survival proteins,the Inhibitors of Apoptosis(IAPs),and IAP regulating proteins.We propose that scutebarbatine A works by releasing the molecular brakes(the IAPs)on apoptosis in cell death-evading cancer cells.Comparison between the cytotoxicity of methanolic extracts of S.barbata leaves and decoctions(Ban Zhi Lian)prepared traditionally,showed substantially different chemical compositions and differential induction of apoptosis.Analyses suggest polyvalency between the constituents in both extracts,and ways to produce enhanced chemopreventive preparations for the treatment of cancer.展开更多
In order to clarify the effect of tip clearance （TC） size on fan performance and the flow field at rotor outlet in a small semi-open axial fan, the experimental investigation was carried out. The tip diameter of tes...In order to clarify the effect of tip clearance （TC） size on fan performance and the flow field at rotor outlet in a small semi-open axial fan, the experimental investigation was carried out. The tip diameter of test fan rotor was 180mm and test TC sizes were lmm （TC=1mm） and 4mm （TC=4mm）. Fan characteristics tests were carried out for two cases of TC size and three-dimensional velocity fields at rotor outlet were measured using a single slant hot-wire probe at four flow-rate conditions. As a result, it was found that the pressure - flow-rate characteristics curves for two cases showed almost the same tendency. However, the ensemble averaged velocity profiles along radial measurement stations of TC-4mm largely changed compared with that of TC=1mm in cases of small flow-rate condition. From the phase-locked averaging results, it was also found that the vortex existed in the rotor outlet flow field of high flow-rate condition for each TC case. Compared with the vortices for TC=1mm and TC=4mm, the vortex for TC=4mm was stronger than that for TC=1mm.展开更多
Photocatalysis technology has been proved to be a potential strategy for removal of organic dyes,however high-power light sources are generally necessary to initiate photocatalytic reaction.In this work,we employed an...Photocatalysis technology has been proved to be a potential strategy for removal of organic dyes,however high-power light sources are generally necessary to initiate photocatalytic reaction.In this work,we employed an excellent photocatalyst of Bi_(2)WO_(6) with visible light harvest and meanwhile an intrinsic ferroelectricity,which realized the efficient degradation of organic dye via the synergetic photopiezocatalysis.Through coupling the illumination by a low-power(9 W)LED and the ultrasonic vibration(120 W)by an ultrasonic cleaner,the nano flower-like Bi_(2)WO_(6) composed of ultrathin nanosheets showed a much more enhanced photopiezocatalysis performance for purification of organic dye than the individual photocatalysis and piezocatalysis.Furthermore,the high mineralization efficiency and the good durability of the Bi_(2)WO_(6) catalyst were demonstrated.The possible mechanism of photopiezocatalysis was finally proposed,where the ultrasound-induced piezoelectric field in Bi_(2)WO_(6) drove photo-generated electrons and holes to diffuse along opposite directions,consequently promoting the separation efficiency of charge carriers.This work indicates that the synergetic photopiezocatalysis by coupling irradiation and ultrasonic vibration is a promising strategy to purify organic pollutants in wastewater.展开更多
The abuse of antibiotics in treating microbial infections has led to the emergence and prevalence of drugresistant bacteria.Thus,the development of novel antibacterial materials is attracting increasing attention.Here...The abuse of antibiotics in treating microbial infections has led to the emergence and prevalence of drugresistant bacteria.Thus,the development of novel antibacterial materials is attracting increasing attention.Here,a series of flexible electrostatic hydrogels with excellent antibacterial ability were constructed using a mixture of nitric oxide(NO)-releasing nitrated chitosan(CSNO)and mesotetra(4-carboxyphenyl)porphine(TCPP)with salmon sperm DNA(ssDNA)solution.When cultured with gram-negative bacteria under solar simulator irradiation,TCPP-CSNO_(m)ssDNA_(n) hydrogels released reactive oxygen species(ROS)and NO to produce peroxynitrite ions(ONOO^(−)).ONOO−is efficient at killing bacteria,thereby improving the antimicrobial ability of photodynamic therapy against gram-negative bacteria.The hydrogels exhibited powerful antibacterial activity in vivo when used to treat skin infections caused by drugresistant bacteria,making them a promising candidate for clinical applications.A string of antibacterial hydrogels that release ROS and NO synergistically can bring new possibilities for effectively killing drug-resistant bacteria and be of great value in anti-infection wound dressings and other applications.展开更多
An experimental platform is constructed to photograph fibers＇ motion within rotor spinning unit, which is mainly composed of a transparent rotor and a transport channel based on the similarity theory. The fibers will...An experimental platform is constructed to photograph fibers＇ motion within rotor spinning unit, which is mainly composed of a transparent rotor and a transport channel based on the similarity theory. The fibers will stretch and gather into a fiber bundle in the transport channel. The velocity of fibers is increasing along the inlet to the outlet of the transport channel, and the fibers＇ maximum velocity appears at the outlet of transport channel. The straightness of the fiber bundle is related to the convergence degree of the transport channel, and the greater the convergence degree is, the straighter the fiber bundle stretches. The results will provide a useful insight to the yam-forming mechanism of rotor spinning.展开更多
To improve the flexural properties of Beetle Elytron Plates(BEPs)and clarify the effect of the transition arcs(chamfers)between the skins and the trabeculae,the chamfers were set in BEPs,and then the influence of the ...To improve the flexural properties of Beetle Elytron Plates(BEPs)and clarify the effect of the transition arcs(chamfers)between the skins and the trabeculae,the chamfers were set in BEPs,and then the influence of the chamfer on BEPs'mechanical properties was investigated via experimentation and the Finite Elemnent Method simulation(FEM).The results indicate that the influence of the chamfer on the flexural properties and ductility was most obvious in the Trabecular Beetle Elytron Plates(TBEPs),less obvious in the Honeycomb Plates(HPs)and basically no efiect was observed on End-trabecular Beetle Elytron Plates(EBEPs).The chamfer can improve the mechanical stability of EBEPSs.As the chamfer diameter increased in the BEPs,the length of the residual trabecular root on the skin increased when failure occurred in the TBEPs.The crack position in the honeycomb wallsof the HPs gradually shifted from the skin to the center.The EBEPs continued to exhibit oblique cracks.From the perspective of the force characteristics of these BEPs.combined with numerical simulation,the influence mechanism of the chamfer on their flcxural propertics was investigated.展开更多
Joint Funds of National Natural Science Foundation of China （ NSFC ） are initiated by different stakeholders, which aim to play a better 9ufdin9 role to support basic research in specific areas and directions. They ...Joint Funds of National Natural Science Foundation of China （ NSFC ） are initiated by different stakeholders, which aim to play a better 9ufdin9 role to support basic research in specific areas and directions. They have formed an important part of the national natural science funding system, which is responsible for advancing science and technology in an expanding frontier. The article would briefly summarize the joint funds strategic goals, programs implementation and achievements in the past decade, and provide a perspective on their future development.展开更多
基金The project supported by the "BaiRen Plan" of Chinese Academy of Sciences
文摘The fluid mechanics of water entry is studied through investigating the underwater acoustics and the supercavitation.Underwater acoustic signals in water entry are extensively measured at about 30 different positions by using a PVDF needle hydrophone.From the measurements we obtain (1)the primary shock wave caused by the impact of the blunt body on free surface;(2)the vapor pressure inside the cavity;(3)the secondary shock wave caused by pulling away of the cavity from free surface;and so on.The supercavitation induced by the blunt body is observed by using a digital high-speed video camera as well as the single shot photography.The periodic and 3 dimensional motion of the supercavitation is revealed.The experiment is carried out at room temperature.
基金The project supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry,China,and the "BaiRen" Plan of Chinese Academy of Sciences
文摘When a shock wave interacts with a group of solid spheres,non-linear aerodynamic behaviors come into effect.The complicated wave reflections such as the Mach reflection occur in the wave propagation process.The wave interactions with vortices behind each sphere's wake cause fluctuation in the pressure profiles of shock waves.This paper reports an experimental study for the aerodynamic processes involved in the interaction between shock waves and solid spheres.A schlieren photography was applied to visualize the various shock waves passing through solid spheres.Pressure measurements were performed along different downstream positions.The experiments were conducted in both rectangular and circular shock tubes.The data with respect to the effect of the sphere array, size,interval distance,incident Mach number,etc.,on the shock wave attenuation were obtained.
文摘In the re-entry phase of a ballistic missile,decoys can be deployed as a mean to overburden enemy defenses.This results in a single track being split into multiple track-lets.Tracking of these track-lets is a critical task as any miss in the tracking procedure can become a cause of a major threat.The tracking process becomes more complicated in the presence of clutter.The low detection rate is one of the factors that may contribute to increasing the difficulty level in terms of tracking in the cluttered environment.This work introduces a new algorithm for the split event detection and target tracking under the framework of the joint integrated probabilistic data association(JIPDA)algorithm.The proposed algorithm is termed as split event-JIPDA(SE-JIPDA).This work establishes the mathematical foundation for the split target detection and tracking mechanism.The performance analysis is made under different simulation conditions to provide a clear insight into the merits of the proposed algorithm.The performance parameters in these simulations are the root mean square error(RMSE),confirmed true track rate(CTTR)and confirmed split true track rate(CSTTR).
基金supported by grants from the National Natural Science Foundation of China (81770176)the special support plan for Zhejiang Province High-Level Talents (2019R52011)。
文摘The management of bacterial infections is becoming a major clinical challenge due to the rapid evolution of antibiotic resistant bacteria.As an excellent candidate to overcome antibiotic resistance,antimicrobial peptides(AMPs)that are produced from the synthetic and natural sources demonstrate a broad-spectrum antimicrobial activity with the high specificity and low toxicity.These peptides possess distinctive structures and functions by employing sophisticated mechanisms of action.This comprehensive review provides a broad overview of AMPs from the origin,structural characteristics,mechanisms of action,biological activities to clinical applications.We finally discuss the strategies to optimize and develop AMP-based treatment as the potential antimicrobial and anticancer therapeutics.
基金the Natural Sciences and Engineering Research Council(NSERC)of Canada and Zhejiang Province Natural Science Foundation of China(LQ20B060002)。
文摘The salt transport in a PEBA membrane used in pervaporative desalination was studied.The concentration profile of salt in the membrane during pervaporation was investigated experimentally using a multilayer membrane.The salt was found to be sorbed in the membrane but was not removed during the pervaporative desalination process,and the salt concentration in the membrane varied linearly with position.High purity water was obtained as the permeate as long as the permeate side was kept dry under vacuum.The accumulated salt uptake in the membrane follows the order of MgCl2 N NaCl N Na2 SO4.The solubility of salt in the membrane follows the order of MgCl2 N NaCl N Na2 SO4.Both the permeability and diffusivity of salt in the membrane follow the order of NaCl N MgCl2 N Na2 SO4.The permeability of salt in the membrane is not influenced by the feed salt concentration.It is mainly determined by the diffusion coefficients.
基金Supported by the Scientific Developing Foundation of Tianjin Municipal Education Commission(2017SK055)the Project Grants 521 Talents Cultivation of Zhejiang Sci-Tech University
文摘Poly-lactic acid(PLA) is widely used as a controlled drug release material and the diffusion property of water within the polymer matrix is closely related to the drug release profile. This paper studies the water diffusion in PLA by molecular dynamic simulations. Free volume analysis indicates that water molecules are expected to fill in the free volumes of the polymer matrix forming water clusters at low water content. Along with the increase of the water concentration, the polymer starts to swell and the density of the system starts to drop.Due to the high mobility of water within water cluster, the calculated diffusion coefficient dramatically increases along with the incensement of water content. Thus, we conclude that the diffusion of water is a self-accelerate process, with higher mobility of water in the case where more water exists.
文摘With 3D orthogonal and pseudo-orthogonal weaves, woven sructures with lengthwise and widthwise changing cross section on one side or both sides of the structure can be constructed. The weave formation and the looming draft creation are discussed in this paper which can be used as references to manufacture woven preforms with changing cross sections.
基金Supported by the Science Foundation of Zhejiang Sci-Tech University(No.0905828-Y)
文摘We establish an extension result of existence and partial regularity for the nonzero Neumann initial-boundary value problem of the Landau-Lifshitz equation with nonpositive anisotropy constants in three or four dimension space. The partial regularity is proved up to the boundary and this result is an important supplement to those for the Dirichlet problem or the homogeneous Neumann problem.
基金the Royal Society for a Newton Advanced Fellowship awarded to ECT(NAF\R2\192001)CEPAMS Funding(Project CPM19)for support of a collaboration project'Scutellaria Anticancer Metabolites'for E.C.T.,C.M.,M-J.R.H.,J.F.and Q.Z.C.M.,M.T.,E.B.,M.R.,G.S.,L.H..and J.L.were also supported by the Institute Strategic Programme‘Molecules from Nature’(BB/P012523/1)+4 种基金the UK Biotechnology and Biological Sciences Research Council.MZ was supported by a CSC visiting scholarship and by the Natural Science Foundation of Zhejiang Province,China(LY21H280009)We thank CAS for the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB27020204)International Partnership Program of CAS(153D31KYSB20160074)we gratefully acknowledge the Ministry of Science and Technology for Foreign Expert Project 2019(G20190113016)the Science and Technology Commission of Shanghai Municipality for Shanghai Talent Recruitment Program 2018 and funds from National Key Laboratory of Plant Molecular Genetics and Shanghai Institute of Plant Physiology and Ecology to ECT for support of this project.
文摘Medicinal plants are an excellent source of structurally diverse,bio-active compounds with potential in the fight against cancer.One of the most promising is Scutellaria barbata,prescribed traditionally for the treatment of cancers.Scutebarbatine A is the major diterpenoid,produced in specialized large,peltate trichomes on leaves of S.barbata.It induces dose-dependent apoptosis,specifically in cancer cells.The major class of proteins down-regulated are pro-survival proteins,the Inhibitors of Apoptosis(IAPs),and IAP regulating proteins.We propose that scutebarbatine A works by releasing the molecular brakes(the IAPs)on apoptosis in cell death-evading cancer cells.Comparison between the cytotoxicity of methanolic extracts of S.barbata leaves and decoctions(Ban Zhi Lian)prepared traditionally,showed substantially different chemical compositions and differential induction of apoptosis.Analyses suggest polyvalency between the constituents in both extracts,and ways to produce enhanced chemopreventive preparations for the treatment of cancer.
文摘In order to clarify the effect of tip clearance （TC） size on fan performance and the flow field at rotor outlet in a small semi-open axial fan, the experimental investigation was carried out. The tip diameter of test fan rotor was 180mm and test TC sizes were lmm （TC=1mm） and 4mm （TC=4mm）. Fan characteristics tests were carried out for two cases of TC size and three-dimensional velocity fields at rotor outlet were measured using a single slant hot-wire probe at four flow-rate conditions. As a result, it was found that the pressure - flow-rate characteristics curves for two cases showed almost the same tendency. However, the ensemble averaged velocity profiles along radial measurement stations of TC-4mm largely changed compared with that of TC=1mm in cases of small flow-rate condition. From the phase-locked averaging results, it was also found that the vortex existed in the rotor outlet flow field of high flow-rate condition for each TC case. Compared with the vortices for TC=1mm and TC=4mm, the vortex for TC=4mm was stronger than that for TC=1mm.
基金financially supported from the National Key Research and Development Program of China(No.2017YFE0127400)the Zhejiang Provincial Natural Science Foundation of China(No.LY17B010004)。
文摘Photocatalysis technology has been proved to be a potential strategy for removal of organic dyes,however high-power light sources are generally necessary to initiate photocatalytic reaction.In this work,we employed an excellent photocatalyst of Bi_(2)WO_(6) with visible light harvest and meanwhile an intrinsic ferroelectricity,which realized the efficient degradation of organic dye via the synergetic photopiezocatalysis.Through coupling the illumination by a low-power(9 W)LED and the ultrasonic vibration(120 W)by an ultrasonic cleaner,the nano flower-like Bi_(2)WO_(6) composed of ultrathin nanosheets showed a much more enhanced photopiezocatalysis performance for purification of organic dye than the individual photocatalysis and piezocatalysis.Furthermore,the high mineralization efficiency and the good durability of the Bi_(2)WO_(6) catalyst were demonstrated.The possible mechanism of photopiezocatalysis was finally proposed,where the ultrasound-induced piezoelectric field in Bi_(2)WO_(6) drove photo-generated electrons and holes to diffuse along opposite directions,consequently promoting the separation efficiency of charge carriers.This work indicates that the synergetic photopiezocatalysis by coupling irradiation and ultrasonic vibration is a promising strategy to purify organic pollutants in wastewater.
基金supported by the National Key R&D Program of China(2021YFB3800900)the National Natural Science Foundation of China(22122501,21875014 and 52073013)Beijing Outstanding Young Scientist Program(BJJWZYJH01201910010024)。
文摘The abuse of antibiotics in treating microbial infections has led to the emergence and prevalence of drugresistant bacteria.Thus,the development of novel antibacterial materials is attracting increasing attention.Here,a series of flexible electrostatic hydrogels with excellent antibacterial ability were constructed using a mixture of nitric oxide(NO)-releasing nitrated chitosan(CSNO)and mesotetra(4-carboxyphenyl)porphine(TCPP)with salmon sperm DNA(ssDNA)solution.When cultured with gram-negative bacteria under solar simulator irradiation,TCPP-CSNO_(m)ssDNA_(n) hydrogels released reactive oxygen species(ROS)and NO to produce peroxynitrite ions(ONOO^(−)).ONOO−is efficient at killing bacteria,thereby improving the antimicrobial ability of photodynamic therapy against gram-negative bacteria.The hydrogels exhibited powerful antibacterial activity in vivo when used to treat skin infections caused by drugresistant bacteria,making them a promising candidate for clinical applications.A string of antibacterial hydrogels that release ROS and NO synergistically can bring new possibilities for effectively killing drug-resistant bacteria and be of great value in anti-infection wound dressings and other applications.
基金supported by National Natural Science Foundation of China under Grant No.51576180Zhejiang Provincial Natural Science Foundation under Grant No.LZ14E050004Project of 521 Talents Cultivation in Zhejiang Sci-Tech University
文摘An experimental platform is constructed to photograph fibers＇ motion within rotor spinning unit, which is mainly composed of a transparent rotor and a transport channel based on the similarity theory. The fibers will stretch and gather into a fiber bundle in the transport channel. The velocity of fibers is increasing along the inlet to the outlet of the transport channel, and the fibers＇ maximum velocity appears at the outlet of transport channel. The straightness of the fiber bundle is related to the convergence degree of the transport channel, and the greater the convergence degree is, the straighter the fiber bundle stretches. The results will provide a useful insight to the yam-forming mechanism of rotor spinning.
基金funded by the National Key R&D Program of China(Grant No.2017YFC0703700).
文摘To improve the flexural properties of Beetle Elytron Plates(BEPs)and clarify the effect of the transition arcs(chamfers)between the skins and the trabeculae,the chamfers were set in BEPs,and then the influence of the chamfer on BEPs'mechanical properties was investigated via experimentation and the Finite Elemnent Method simulation(FEM).The results indicate that the influence of the chamfer on the flexural properties and ductility was most obvious in the Trabecular Beetle Elytron Plates(TBEPs),less obvious in the Honeycomb Plates(HPs)and basically no efiect was observed on End-trabecular Beetle Elytron Plates(EBEPs).The chamfer can improve the mechanical stability of EBEPSs.As the chamfer diameter increased in the BEPs,the length of the residual trabecular root on the skin increased when failure occurred in the TBEPs.The crack position in the honeycomb wallsof the HPs gradually shifted from the skin to the center.The EBEPs continued to exhibit oblique cracks.From the perspective of the force characteristics of these BEPs.combined with numerical simulation,the influence mechanism of the chamfer on their flcxural propertics was investigated.
基金supported by grants from the National Natural Science Foundation of China (grants M1121009)
文摘Joint Funds of National Natural Science Foundation of China （ NSFC ） are initiated by different stakeholders, which aim to play a better 9ufdin9 role to support basic research in specific areas and directions. They have formed an important part of the national natural science funding system, which is responsible for advancing science and technology in an expanding frontier. The article would briefly summarize the joint funds strategic goals, programs implementation and achievements in the past decade, and provide a perspective on their future development.
