Air plasma ablation behavior of Cf/(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C-SiC composite was studied systematically with the surface temperature above 2000℃ at the ablation center.It presents a linear recession r...Air plasma ablation behavior of Cf/(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C-SiC composite was studied systematically with the surface temperature above 2000℃ at the ablation center.It presents a linear recession rate of 0.15μm/s and a mass recession rate of 2.05 mg/s after ablation at 4 MW/m^(2)(2000℃)for 300 s.Associated with the temperature gradient of the ablation surface,the oxidation products at different locations mainly consist of(TiZrHfNbTa)O_(x),(Zr_(x)Hf_(1-x))6(NbyTa_(1-y))_(2)O_(17),Ti(Nb_(x)Ta_(1-x))_(2)O_(7),(Hf_(x)Zr_(1-x))SiO_(4),and SiO_(2).Due to the synergistic effect of the multi-component oxides,oxidation products form a protective structure composed of high melting point oxide skeleton filled with relatively low melting point phases.It retards oxygen inward diffusion and prevents the composite fragmentation caused by plasma mechanical scouring.It is believed that the results would be helpful for further improving the ablation resistance by component design of high entropy ceramics and their composites.展开更多
The ultra-lightweight and multifunction integrated thermal protection materials are critical for the de-velopment of hypersonic vehicles.Although various materials have been developed as potential thermal protection m...The ultra-lightweight and multifunction integrated thermal protection materials are critical for the de-velopment of hypersonic vehicles.Although various materials have been developed as potential thermal protection materials,most of them generally present a singular function.It is still challenging to meet the multifunctional requirements of ultra-lightweight,thermal insulation,electromagnetic interference(EMI)shielding,and high-temperature ablation resistance.Herein,a gradient C_(f)/(CrZrHfNbTa)C-SiC composite is designed and fabricated based on the bionic strategy of capillary adsorption and transport.The devel-oped gradient C_(f)/(CrZrHfNbTa)C-SiC composite is as light as 0.74 g/cm^(3),which shows excellent ablation resistance(-3.88μm/s at 2000℃).It also presents competitive thermal insulation performance with a back temperature below 152℃while enduring 1300℃on the front side.The thermal conductivity of the gradient composite is 0.202 W mr^(-1) K^(-1).Furthermore,the gradient C_(f)/(CrZrHfNbTa)C-SiC composite offers remarkable EMI shielding performance with mean total EMI shielding efficiency(SE_(T))larger than 45 dB in an ultra-wide frequency range of 0-100 GHz.The excellent multifunctional performance with ultra-lightweight makes the gradient C_(f)/(CrZrHfNbTa)C-SiC composite ideal thermal protection materials for hypersonic vehicles.This work provides a flexible strategy for constructing gradient composites for multifunctional applications.展开更多
In this work,C_(f)/(CrZrHfNbTa)C-SiC high-entropy ceramic matrix composites with good load-bearing,elec-tromagnetic shielding and ablation resistance were designed and reported for the first time.The compos-ites were ...In this work,C_(f)/(CrZrHfNbTa)C-SiC high-entropy ceramic matrix composites with good load-bearing,elec-tromagnetic shielding and ablation resistance were designed and reported for the first time.The compos-ites were fabricated by an efficient combined processing of slurry infiltration lamination(SIL)and precur-sor infiltration and pyrolysis(PIP).Density and porosity of the as-fabricated composites are 2.72 g/cm^(3) and 12.44 vol.%,respectively,and the flexural strength is 185±13 MPa.Due to the carbon fiber rein-forcement with high conductivity and strong reflection,and high-entropy(CrZrHfNbTa)C ceramic matrix with strong absorbability,the total Electromagnetic interference shielding efficiency(SET)of the compos-ites with a thickness of 3 mm are as high as 88.2 dB and 90 dB respectively in X-band and Ku-band.This means that higher than 99.999999%electromagnetic shielding is achieved at 8-18 GHz,showing excel-lent electromagnetic shielding performance.The C_(f)/(CrZrHfNbTa)C-SiC composites also present excellent ablation resistance,with the linear and mass ablation rates of 0.9μm/s and 1.82 mg/s after ablation at the heat flux of 5 MW/m^(2) for 300 s(∼2450℃).This work opens a new insight for the synergistic de-sign of structural and functional integrated materials with load-bearing,electromagnetic shielding and ablation resistance,etc.展开更多
Acoustic waves are promising for information encryption in electromagnetic shielding environments,or underwater.However,current encryption methods using acoustic waves are prone to information leakage during the decry...Acoustic waves are promising for information encryption in electromagnetic shielding environments,or underwater.However,current encryption methods using acoustic waves are prone to information leakage during the decryption process due to their limited information capacity.Herein,we propose and experimentally demonstrate a novel acoustic holographic encryption framework based on cascaded acoustic holography,enabling encrypted information to be spatially split into two acoustic holographic plates(AHPs).To achieve this,we introduce a physics-enhanced cascaded acoustic hologram deep neural network method that inversely optimizes the phase offset distributions of AHPs.Both numerical and experimental results show that each AHP serves as a spatially separable secret key,carrying a portion of the encrypted information as a unique holographic image.Notably,the complete encrypted image,which differs from the individual holographic images generated by each AHP,is only revealed when both AHPs are appropriately cascaded along the diffraction path.This significantly enhances both information capacity and security.Moreover,we present an enhanced acoustic holographic encryption scheme that allows for the encryption of two holographic images using just three AHPs.A distinct example of underwater communication based on the proposed cascaded acoustic holographic encryption framework is further demonstrated,highlighting its capacity for high-capacity and enhanced-security parallel transmission of multiple messages to multiple receivers.With the advantages of high security,high scalability,and high fidelity,our cascaded acoustic holographic encryption framework has promising applications in fields such as acoustic encryption and underwater communication.展开更多
Stem cell-based tissue engineering has provided a promising platform for repairing of bone defects.However,the use of exogenous bone marrow mesenchymal stem cells(BMSCs)still faces many challenges such as limited sour...Stem cell-based tissue engineering has provided a promising platform for repairing of bone defects.However,the use of exogenous bone marrow mesenchymal stem cells(BMSCs)still faces many challenges such as limited sources and potential risks.It is important to develop new approach to effectively recruit endogenous BMSCs and capture them for in situ bone regeneration.Here,we designed an acoustically responsive scaffold(ARS)and embedded it into SDF-1/BMP-2 loaded hydrogel to obtain biomimetic hydrogel scaffold complexes(BSC).The SDF-1/BMP-2 cytokines can be released on demand from the BSC implanted into the defected bone via pulsed ultrasound(p-US)irradiation at optimized acoustic parameters,recruiting the endogenous BMSCs to the bone defected or BSC site.Accompanied by the daily p-US irradiation for 14 days,the alginate hydrogel was degraded,resulting in the exposure of ARS to these recruited host stem cells.Then another set of sinusoidal continuous wave ultrasound(s-US)irradiation was applied to excite the ARS intrinsic resonance,forming highly localized acoustic field around its surface and generating enhanced acoustic trapping force,by which these recruited endogenous stem cells would be captured on the scaffold,greatly promoting them to adhesively grow for in situ bone tissue regeneration.Our study provides a novel and effective strategy for in situ bone defect repairing through acoustically manipulating endogenous BMSCs.展开更多
Acoustic tweezers have great application prospects because they allow noncontact and noninvasive manipulation of microparticles in a wide range of media.However,the nontransparency and heterogeneity of media in practi...Acoustic tweezers have great application prospects because they allow noncontact and noninvasive manipulation of microparticles in a wide range of media.However,the nontransparency and heterogeneity of media in practical applications complicate particle trapping and manipulation.In this study,we designed a 1.04 MHz 256-element 2D matrix array for 3D acoustic tweezers to guide and monitor the entire process using real-time 3D ultrasonic images,thereby enabling acoustic manipulation in nontransparent media.Furthermore,we successfully performed dynamic 3D manipulations on multiple microparticles using multifoci and vortex traps.We achieved 3D particle manipulation in heterogeneous media(through resin baffle and ex vivo macaque and human skulls)by introducing a method based on the time reversal principle to correct the phase and amplitude distortions of the acoustic waves.Our results suggest cutting-edge applications of acoustic tweezers such as acoustical drug delivery,controlled micromachine transfer,and precise treatment.展开更多
Fiber damage and uniform interphase preparation are the main challenges in conventional short fiber reinforced ceramic matrix composites.In this work,we develop a novel processing route in fabrication of short carbon ...Fiber damage and uniform interphase preparation are the main challenges in conventional short fiber reinforced ceramic matrix composites.In this work,we develop a novel processing route in fabrication of short carbon fiber reinforced ZrB_(2)-SiC composites(C_(sf)/ZrB_(2)-SiC)overcoming the above two issues.At first,C_(sf) preforms with oriented designation and uniform PyC/SiC interphase are fabricated via direct ink writing(DIW)of short carbon fiber paste followed by chemical vapor infiltration.After that,ZrB_(2) and SiC are introduced into the preforms by slurry impregnation and reactive melt infiltration,respectively.Microstructure evolution and optimization of the composites during fabrication are investigated in detail.The as-fabricated C_(sf)/ZrB_(2)-SiC composites have a bulk density of 2.47 g/cm^(3),with uniform weak interphase and without serious fiber damage.Consequently,non-brittle fracture occurs in the C_(sf)/ZrB_(2)-SiC composites with widespread toughening mechanisms such as crack deflection and bridging,interphase debonding,and fiber pull-out.This work provides a new opportunity to the material design and selection of short fiber reinforced composites.展开更多
C_(f)/Ta_(x)Hf_(1−x)C–SiC composites are ideal thermal structural materials for service under extreme conditions of hypersonic vehicles.However,how to synthesize TaxHf1-xC powders and efficiently fabricate C_(f)/Ta_(...C_(f)/Ta_(x)Hf_(1−x)C–SiC composites are ideal thermal structural materials for service under extreme conditions of hypersonic vehicles.However,how to synthesize TaxHf1-xC powders and efficiently fabricate C_(f)/Ta_(x)Hf_(1−x)C–SiC composites still faces some challenges.Furthermore,mechanical properties and thermophysical properties of Ta_(x)Hf_(1−x)C vary with the composition,but not monotonically.In-depth analysis of mechanical behaviors of the C_(f)/Ta_(x)Hf_(1−x)C–SiC composites is extremely important for their development and applications.In this study,the Ta_(x)Hf_(1−x)C powders(x=0.2,0.5,0.8)were successfully synthesized via solid solution of TaC and HfC at a relatively low temperature of 1800℃,with a small amount of Si as an additive.Subsequently,the efficient fabrication of 2D-C_(f)/Ta_(x)Hf_(1−x)C–SiC composites was achieved by slurry impregnation and lamination(SIL)combined with precursor infiltration and pyrolysis(PIP).In addition,the mechanical behavior of the composites was investigated systematically.It is demonstrated that the composites present remarkable non-brittle fractures,including a large number of fiber pull out and interphase debonding.Also,the fracture failure involves a complex process of microcrack generation and propagation,matrix cracking,and layer fracture.Moreover,the interfacial bonding between the fibers and the matrix is enhanced as the Ta∶Hf ratio decreases from 4∶1 to 1∶4.As a result,C_(f)/Ta_(0.2)Hf_(0.8)C–SiC composites exhibit exceptional flexural strength of 437±19 MPa,improved by 46%compared with C_(f)/Ta_(0.8)Hf_(0.2)C–SiC(299±19 MPa).This study provides a new perception of design and fabrication of ultra-high-temperature ceramic(UHTC)matrix composites with high performance.展开更多
基金supported by the National Key R&D Program of China(No.2022YFB3707700)the Program of Shanghai Academic/Technology Research Leader(No.23XD1424300)the National Natural Science Foundation of China(No.52332003).
文摘Air plasma ablation behavior of Cf/(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C-SiC composite was studied systematically with the surface temperature above 2000℃ at the ablation center.It presents a linear recession rate of 0.15μm/s and a mass recession rate of 2.05 mg/s after ablation at 4 MW/m^(2)(2000℃)for 300 s.Associated with the temperature gradient of the ablation surface,the oxidation products at different locations mainly consist of(TiZrHfNbTa)O_(x),(Zr_(x)Hf_(1-x))6(NbyTa_(1-y))_(2)O_(17),Ti(Nb_(x)Ta_(1-x))_(2)O_(7),(Hf_(x)Zr_(1-x))SiO_(4),and SiO_(2).Due to the synergistic effect of the multi-component oxides,oxidation products form a protective structure composed of high melting point oxide skeleton filled with relatively low melting point phases.It retards oxygen inward diffusion and prevents the composite fragmentation caused by plasma mechanical scouring.It is believed that the results would be helpful for further improving the ablation resistance by component design of high entropy ceramics and their composites.
基金support from the National Natural Science Foun-dation of China(Nos.52472114 and 52332003)the Pro-gram of Shanghai Academic/Technology Research Leader(No.23XD1424300)are greatly acknowledged.
文摘The ultra-lightweight and multifunction integrated thermal protection materials are critical for the de-velopment of hypersonic vehicles.Although various materials have been developed as potential thermal protection materials,most of them generally present a singular function.It is still challenging to meet the multifunctional requirements of ultra-lightweight,thermal insulation,electromagnetic interference(EMI)shielding,and high-temperature ablation resistance.Herein,a gradient C_(f)/(CrZrHfNbTa)C-SiC composite is designed and fabricated based on the bionic strategy of capillary adsorption and transport.The devel-oped gradient C_(f)/(CrZrHfNbTa)C-SiC composite is as light as 0.74 g/cm^(3),which shows excellent ablation resistance(-3.88μm/s at 2000℃).It also presents competitive thermal insulation performance with a back temperature below 152℃while enduring 1300℃on the front side.The thermal conductivity of the gradient composite is 0.202 W mr^(-1) K^(-1).Furthermore,the gradient C_(f)/(CrZrHfNbTa)C-SiC composite offers remarkable EMI shielding performance with mean total EMI shielding efficiency(SE_(T))larger than 45 dB in an ultra-wide frequency range of 0-100 GHz.The excellent multifunctional performance with ultra-lightweight makes the gradient C_(f)/(CrZrHfNbTa)C-SiC composite ideal thermal protection materials for hypersonic vehicles.This work provides a flexible strategy for constructing gradient composites for multifunctional applications.
基金supported by the National Key R&D Program of China(no.2022YFB3707700)Program of Shang-hai Academic/Technology Research Leader(no.23XD1424300)National Natural Science Foundation of China(no.52332003).
文摘In this work,C_(f)/(CrZrHfNbTa)C-SiC high-entropy ceramic matrix composites with good load-bearing,elec-tromagnetic shielding and ablation resistance were designed and reported for the first time.The compos-ites were fabricated by an efficient combined processing of slurry infiltration lamination(SIL)and precur-sor infiltration and pyrolysis(PIP).Density and porosity of the as-fabricated composites are 2.72 g/cm^(3) and 12.44 vol.%,respectively,and the flexural strength is 185±13 MPa.Due to the carbon fiber rein-forcement with high conductivity and strong reflection,and high-entropy(CrZrHfNbTa)C ceramic matrix with strong absorbability,the total Electromagnetic interference shielding efficiency(SET)of the compos-ites with a thickness of 3 mm are as high as 88.2 dB and 90 dB respectively in X-band and Ku-band.This means that higher than 99.999999%electromagnetic shielding is achieved at 8-18 GHz,showing excel-lent electromagnetic shielding performance.The C_(f)/(CrZrHfNbTa)C-SiC composites also present excellent ablation resistance,with the linear and mass ablation rates of 0.9μm/s and 1.82 mg/s after ablation at the heat flux of 5 MW/m^(2) for 300 s(∼2450℃).This work opens a new insight for the synergistic de-sign of structural and functional integrated materials with load-bearing,electromagnetic shielding and ablation resistance,etc.
基金supported by the National Key R&D Program of China (Grant No. 2021YFB3801800)the Guangdong Basic and Applied Basic Research Foundation (Grant Nos. 2023A1515012823, and 2022A1515110319)+3 种基金the Youth Innovative Talent Project from the Department of Education of Guangdong Province (Grant No. 2022KQNCX022)the National Natural Science Foundation of China (Grant No. 11974372)the Shenzhen Science and Technology Program (Grant No. RCJC20221008092808013)the Discipline Construction Project of Guangdong Medical University (Grant No. GDMUB2023023)。
文摘Acoustic waves are promising for information encryption in electromagnetic shielding environments,or underwater.However,current encryption methods using acoustic waves are prone to information leakage during the decryption process due to their limited information capacity.Herein,we propose and experimentally demonstrate a novel acoustic holographic encryption framework based on cascaded acoustic holography,enabling encrypted information to be spatially split into two acoustic holographic plates(AHPs).To achieve this,we introduce a physics-enhanced cascaded acoustic hologram deep neural network method that inversely optimizes the phase offset distributions of AHPs.Both numerical and experimental results show that each AHP serves as a spatially separable secret key,carrying a portion of the encrypted information as a unique holographic image.Notably,the complete encrypted image,which differs from the individual holographic images generated by each AHP,is only revealed when both AHPs are appropriately cascaded along the diffraction path.This significantly enhances both information capacity and security.Moreover,we present an enhanced acoustic holographic encryption scheme that allows for the encryption of two holographic images using just three AHPs.A distinct example of underwater communication based on the proposed cascaded acoustic holographic encryption framework is further demonstrated,highlighting its capacity for high-capacity and enhanced-security parallel transmission of multiple messages to multiple receivers.With the advantages of high security,high scalability,and high fidelity,our cascaded acoustic holographic encryption framework has promising applications in fields such as acoustic encryption and underwater communication.
基金National Key R&D Program of China(2020YFA0908800)National Natural Science Foundation of China(81871376,32171365,82071927,81771853,81571674)+6 种基金Guangzhou Science and Technology Program Project(202002030104,202102080128,202201020284)Talent Research Foundation of Guangdong Second Provincial General Hospital(YN-2018-002)Youth Research Foundation of Guangdong Second Provincial General Hospital(YQ-2019-011)The science foundation of Guangdong Second Provincial General Hospital(TJGC-2021002)Natural Science Foundation of Guangdong Province(2021A1515011260,2018A030313824)Shenzhen Science and Technology Innovation Committee(JCYJ20190812171820731)Research Project of Traditional Chinese Medicine Bureau of Guangdong Provincial.
文摘Stem cell-based tissue engineering has provided a promising platform for repairing of bone defects.However,the use of exogenous bone marrow mesenchymal stem cells(BMSCs)still faces many challenges such as limited sources and potential risks.It is important to develop new approach to effectively recruit endogenous BMSCs and capture them for in situ bone regeneration.Here,we designed an acoustically responsive scaffold(ARS)and embedded it into SDF-1/BMP-2 loaded hydrogel to obtain biomimetic hydrogel scaffold complexes(BSC).The SDF-1/BMP-2 cytokines can be released on demand from the BSC implanted into the defected bone via pulsed ultrasound(p-US)irradiation at optimized acoustic parameters,recruiting the endogenous BMSCs to the bone defected or BSC site.Accompanied by the daily p-US irradiation for 14 days,the alginate hydrogel was degraded,resulting in the exposure of ARS to these recruited host stem cells.Then another set of sinusoidal continuous wave ultrasound(s-US)irradiation was applied to excite the ARS intrinsic resonance,forming highly localized acoustic field around its surface and generating enhanced acoustic trapping force,by which these recruited endogenous stem cells would be captured on the scaffold,greatly promoting them to adhesively grow for in situ bone tissue regeneration.Our study provides a novel and effective strategy for in situ bone defect repairing through acoustically manipulating endogenous BMSCs.
基金supported in part by the National Natural Science Foundation of China Grant(Grant Nos.81527901,61571431,11774370,81827807,and 81827802)Shenzhen Peacock Plan(Grant No.KQTD20170810160424889)+1 种基金Scientific Instruments Funding of Chinese Academy of Sciences(Grant No.YJKYYQ20190077)Shenzhen Key Laboratory of ultrasound imaging and therapy(Grant No.ZDSYS20180206180631473).
文摘Acoustic tweezers have great application prospects because they allow noncontact and noninvasive manipulation of microparticles in a wide range of media.However,the nontransparency and heterogeneity of media in practical applications complicate particle trapping and manipulation.In this study,we designed a 1.04 MHz 256-element 2D matrix array for 3D acoustic tweezers to guide and monitor the entire process using real-time 3D ultrasonic images,thereby enabling acoustic manipulation in nontransparent media.Furthermore,we successfully performed dynamic 3D manipulations on multiple microparticles using multifoci and vortex traps.We achieved 3D particle manipulation in heterogeneous media(through resin baffle and ex vivo macaque and human skulls)by introducing a method based on the time reversal principle to correct the phase and amplitude distortions of the acoustic waves.Our results suggest cutting-edge applications of acoustic tweezers such as acoustical drug delivery,controlled micromachine transfer,and precise treatment.
基金support from the Key Research Program of Frontier Sciences,CAS(No.QYZDY-SSW-JSC031)the projects supported by State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology(No.2021-KF-5)State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University(No.KF2116)are greatly acknowledged.
文摘Fiber damage and uniform interphase preparation are the main challenges in conventional short fiber reinforced ceramic matrix composites.In this work,we develop a novel processing route in fabrication of short carbon fiber reinforced ZrB_(2)-SiC composites(C_(sf)/ZrB_(2)-SiC)overcoming the above two issues.At first,C_(sf) preforms with oriented designation and uniform PyC/SiC interphase are fabricated via direct ink writing(DIW)of short carbon fiber paste followed by chemical vapor infiltration.After that,ZrB_(2) and SiC are introduced into the preforms by slurry impregnation and reactive melt infiltration,respectively.Microstructure evolution and optimization of the composites during fabrication are investigated in detail.The as-fabricated C_(sf)/ZrB_(2)-SiC composites have a bulk density of 2.47 g/cm^(3),with uniform weak interphase and without serious fiber damage.Consequently,non-brittle fracture occurs in the C_(sf)/ZrB_(2)-SiC composites with widespread toughening mechanisms such as crack deflection and bridging,interphase debonding,and fiber pull-out.This work provides a new opportunity to the material design and selection of short fiber reinforced composites.
基金support from the National Key R&D Program of China(No.2022YFB3707700)Program of Shanghai Academic/Technology Research Leader(No.23XD1424300)the National Natural Science Foundation of China(No.52332003)are greatly acknowledged.
文摘C_(f)/Ta_(x)Hf_(1−x)C–SiC composites are ideal thermal structural materials for service under extreme conditions of hypersonic vehicles.However,how to synthesize TaxHf1-xC powders and efficiently fabricate C_(f)/Ta_(x)Hf_(1−x)C–SiC composites still faces some challenges.Furthermore,mechanical properties and thermophysical properties of Ta_(x)Hf_(1−x)C vary with the composition,but not monotonically.In-depth analysis of mechanical behaviors of the C_(f)/Ta_(x)Hf_(1−x)C–SiC composites is extremely important for their development and applications.In this study,the Ta_(x)Hf_(1−x)C powders(x=0.2,0.5,0.8)were successfully synthesized via solid solution of TaC and HfC at a relatively low temperature of 1800℃,with a small amount of Si as an additive.Subsequently,the efficient fabrication of 2D-C_(f)/Ta_(x)Hf_(1−x)C–SiC composites was achieved by slurry impregnation and lamination(SIL)combined with precursor infiltration and pyrolysis(PIP).In addition,the mechanical behavior of the composites was investigated systematically.It is demonstrated that the composites present remarkable non-brittle fractures,including a large number of fiber pull out and interphase debonding.Also,the fracture failure involves a complex process of microcrack generation and propagation,matrix cracking,and layer fracture.Moreover,the interfacial bonding between the fibers and the matrix is enhanced as the Ta∶Hf ratio decreases from 4∶1 to 1∶4.As a result,C_(f)/Ta_(0.2)Hf_(0.8)C–SiC composites exhibit exceptional flexural strength of 437±19 MPa,improved by 46%compared with C_(f)/Ta_(0.8)Hf_(0.2)C–SiC(299±19 MPa).This study provides a new perception of design and fabrication of ultra-high-temperature ceramic(UHTC)matrix composites with high performance.
