Wood,a readily available and sustainable natural resource,has found widespread use in construction and furniture.However,its inherent flammability poses a potential fire risk.Although intumescent fire-retardant coatin...Wood,a readily available and sustainable natural resource,has found widespread use in construction and furniture.However,its inherent flammability poses a potential fire risk.Although intumescent fire-retardant coatings effectively mitigate this risk,achieving high transparency in such coatings presents a significant challenge.In our approach,we employed a cross-linked network of phytic acid anion and N-[3-(trimethoxysilyl)propyl]-N,N,N-trimethylammonium cation to create a transparent"three-in-one"intumescent coating.The collaborative P/N/Si flame-retardant effect markedly improved the intumescent char-forming capability,preventing the wood from rapid decomposition.This resulted in a substantial reduction in heat release(13.9%decrease in THR)and an increased limiting oxygen index(LOI)value of 35.5%.Crucially,the high transparency of the coating ensured minimal impact on the wood's appearance,allowing the natural wood grains to remain clearly visible.This innovative approach provides a straightforward method for developing transparent intumescent flame-retardant coatings suitable for wooden substrates.The potential applications extend to preserving ancient buildings and heritage conservation efforts.展开更多
Silica-coated carbonyl iron particles （CIPs） are fabricated with the Stober method to improve their heat-resistance and wave-aSsorption properties. The morphology, heat-resistance, electromagnetic properties and mic...Silica-coated carbonyl iron particles （CIPs） are fabricated with the Stober method to improve their heat-resistance and wave-aSsorption properties. The morphology, heat-resistance, electromagnetic properties and microwave absorption of raw-CIPs and silica-coated CIPs are investigated using a scanning electron microscope, an energy dispersive spectrometer, a thermal-gravimetric analyzer, and a network analyzer. The results show that the heat-resistance of silica-coated CIPs is better than that of raw CIFs. The reflection losses exceeding -lOdB of silica-coated CIPs are obtained in the frequency range 9.5-12.4 GHz for the absorber thickness of 2.3 mm, and the same reflection losses of uncoated CIPs reach the data in the lower frequency range for the same thickness. The enhanced microwave absorption of silica-coated CIPs can be ascribed to the combination of proper electromagnetic impedance match and the decrease of dielectric permittivity.展开更多
With increasing demand for scratch-resistant flexible electro-nics,the development of transparent coatings with good scratch resistance and self-healing properties has emerged as a key research topic.In this study,a h...With increasing demand for scratch-resistant flexible electro-nics,the development of transparent coatings with good scratch resistance and self-healing properties has emerged as a key research topic.In this study,a high-strength self-healing poly(urethane-urea)(PUU)-based nanocomposite coating was prepared by introducing functionalized nanodiamond(ND)into a PUU matrix via solution blending.The PUU matrix had hard-segment repeating units and was constructed using iso-phorone diamine and isophorone isocyanate.The ND particles were modifed using a silane coupling agent,3-aminopropyl-triethoxysilane,to obtain well-dispersed KH-ND nanoparticles.KH-ND promoted microphase separation in the PU matrix,inducing the formation of dense and homogeneous hard domains that dissipated stress,prevented further crack devel-opment,and improved the mechanical properties and scratch resistance of the coating.In addition,the coating exhibited excellent self-healing properties.Fourier-transform infrared spectroscopy,scanning electron microscopy,and atomic force microscopy were used to characterize the self-healing and hardening mechanisms of the coating.The environmentally friendly PUU/KH-ND coating is easy to prepare and has broad application prospects in transparent and anti-scratch coatings for flexible electronics,automobiles,and home appliances.展开更多
In this paper,the properties of different low-density heat-resistant coating prescriptions were compared,and a heat-resistant coating with a density of 0.65 g/cm^(3),a tensile strength of 2.04 MPa,and a thermal conduc...In this paper,the properties of different low-density heat-resistant coating prescriptions were compared,and a heat-resistant coating with a density of 0.65 g/cm^(3),a tensile strength of 2.04 MPa,and a thermal conductivity of 0.126 W/(m·K)was obtained.The thermal performance of the coating was characterized by an oxygen-acetylene ablation test,a hot radiation test using a quartz lamp and in an arc-heated wind tunnel test.The results indicated that the low-density heat-resistant coating prescription has advantages of high temperature resistance,erosion resistance,ablative resistance and excellent heat resistance,which can satisfy the heat resistance requirements of new-generation launch vehicle fairings.The successful application of this heat-resistant coating technology resolved the problems of low efficiency and poor adhesive performance of the traditional hand-pasted cork process,and realized the rapid spray application of the thermal protection layer,effectively improved the manufacturing efficiency and production quality of the heat-resistant layer of new-generation launch vehicle fairings.展开更多
The objective of this review is to present the results on the production techniques, process parameters and compositions of heat-resistant coatings for graphite and carbon-carbon composites. The data reported concern ...The objective of this review is to present the results on the production techniques, process parameters and compositions of heat-resistant coatings for graphite and carbon-carbon composites. The data reported concern the resistance of such protective coatings in air at temperatures up to 2273 K and in the high-speed flows of oxidizing gas media taking place in the spacecraft equipment. Coatings of this type, generally, have a multilayer structure based on the refractory compounds such as carbides, borides, silicides of transition metals and oxides with a high melting temperature. An efficient heat-resistant coating for carbon-based materials should be composed of three layers from which each fulfills its own function. The paper presents a new complex method for formation of heat-resistant coatings on the carbon-based materials. The method combines the vacuum-activated diffusion saturation in the presence of a liquid-phase and self-propagating high-temperature synthesis (SHS) simultaneously.展开更多
The linewidth of electromagnetically induced transparency（EIT） in a coated Rb vapor cell was studied under a magnetic field gradient.The nonlinear broadening of the EIT linewidth with the magnetic field gradient was...The linewidth of electromagnetically induced transparency（EIT） in a coated Rb vapor cell was studied under a magnetic field gradient.The nonlinear broadening of the EIT linewidth with the magnetic field gradient was observed.It was found that the motional averaging of the field gradient was more pronounced at higher laser intensities and larger beam sizes.In the same regime,there was a small linewidth decrease with the increasing magnetic field gradient.We have established a Monte-Carlo model,which gave results in good qualitative agreement with our experiment.Physics pictures for the above phenomena were also suggested.These results provide an understanding of the EIT linewidth behavior under motional averaging,and should be useful for applications in quantum optics and metrology based on coated vapor cells.展开更多
Transparent heat mirror which allows the transmission of visible sunlight while reflects the infrared thermal energy is an effective building energy efficiency technology for hot climatic regions.In this work,a five-l...Transparent heat mirror which allows the transmission of visible sunlight while reflects the infrared thermal energy is an effective building energy efficiency technology for hot climatic regions.In this work,a five-layer dielectric/metal/dielectric/metal/dielectric(DMDMD)coating of Si_(3)N_(4)/Ag/Si_(3)N_(4)/Ag/Si_(3)N_(4)structure is proposed.The radiative properties of the five-layer coatings are theoretically investigated by transfer matrix method.The thicknesses of the layers are optimized by using particle swarm optimization method.The sample of the designed Si_(3)N_(4)/Ag/Si_(3)N_(4)/Ag/Si_(3)N_(4)coating is prepared and the building energy performance when applying the DMDMD coating in a simple office room is also investigated,taking the hot weather condition of Guangzhou,China as an example.The simulated results show that the Tave+Rave value of the five-layer coating is 8%higher than that of the three-layer coating,and the long-wave emittance of the five-layer coating is 24.8%lower than that of the three-layer coating.And the application of the five-layer coatings on the glazed window could provide the highest energy saving rate of 8.9%when compared with the traditional low-e coatings.展开更多
Three coating methods (slot, dip and blade coatings) were used separately to coat a well-dispersed single-wall carbonnanotube (SWCNT) solution on polyethylene terephthalate (PET) film, and the resulting optical and el...Three coating methods (slot, dip and blade coatings) were used separately to coat a well-dispersed single-wall carbonnanotube (SWCNT) solution on polyethylene terephthalate (PET) film, and the resulting optical and electronic properties were measured and compared. It was found that the sheet resistance and the transparency of the SWCNT coated film decreased as the coating speed increased for dip and blade coatings, but were independent of the coating speed for slot coating. All three coating methods were able to produce transparent conductive film with transparency above 85% and sheet resistance close to 1000 ohm/sq. For industrial production, the slot die coating method appears to be more suitable in terms of high coating speed and uniformity of optical and electronic properties.展开更多
基金financially supported by State Grid Corporation of China Science and Technology Project Funding(No.52199723000M)the National Natural Science Foundation of China(No.52122302)Sichuan Science and Technology Program(No.2023NSFSC1943)。
文摘Wood,a readily available and sustainable natural resource,has found widespread use in construction and furniture.However,its inherent flammability poses a potential fire risk.Although intumescent fire-retardant coatings effectively mitigate this risk,achieving high transparency in such coatings presents a significant challenge.In our approach,we employed a cross-linked network of phytic acid anion and N-[3-(trimethoxysilyl)propyl]-N,N,N-trimethylammonium cation to create a transparent"three-in-one"intumescent coating.The collaborative P/N/Si flame-retardant effect markedly improved the intumescent char-forming capability,preventing the wood from rapid decomposition.This resulted in a substantial reduction in heat release(13.9%decrease in THR)and an increased limiting oxygen index(LOI)value of 35.5%.Crucially,the high transparency of the coating ensured minimal impact on the wood's appearance,allowing the natural wood grains to remain clearly visible.This innovative approach provides a straightforward method for developing transparent intumescent flame-retardant coatings suitable for wooden substrates.The potential applications extend to preserving ancient buildings and heritage conservation efforts.
文摘Silica-coated carbonyl iron particles （CIPs） are fabricated with the Stober method to improve their heat-resistance and wave-aSsorption properties. The morphology, heat-resistance, electromagnetic properties and microwave absorption of raw-CIPs and silica-coated CIPs are investigated using a scanning electron microscope, an energy dispersive spectrometer, a thermal-gravimetric analyzer, and a network analyzer. The results show that the heat-resistance of silica-coated CIPs is better than that of raw CIFs. The reflection losses exceeding -lOdB of silica-coated CIPs are obtained in the frequency range 9.5-12.4 GHz for the absorber thickness of 2.3 mm, and the same reflection losses of uncoated CIPs reach the data in the lower frequency range for the same thickness. The enhanced microwave absorption of silica-coated CIPs can be ascribed to the combination of proper electromagnetic impedance match and the decrease of dielectric permittivity.
基金supported by the Fundamental Research Funds for the Central Universities[Grant No.HIT.0CEF.2022011]National Science Fund for Distinguished Young Scholars[Grant No.51625201]+1 种基金National Youth Science Funds of China[Grant No.52102039]Key Research and Development Program of Heilongjiang Province[Grant No.GA21D001,2022ZX06C05].
文摘With increasing demand for scratch-resistant flexible electro-nics,the development of transparent coatings with good scratch resistance and self-healing properties has emerged as a key research topic.In this study,a high-strength self-healing poly(urethane-urea)(PUU)-based nanocomposite coating was prepared by introducing functionalized nanodiamond(ND)into a PUU matrix via solution blending.The PUU matrix had hard-segment repeating units and was constructed using iso-phorone diamine and isophorone isocyanate.The ND particles were modifed using a silane coupling agent,3-aminopropyl-triethoxysilane,to obtain well-dispersed KH-ND nanoparticles.KH-ND promoted microphase separation in the PU matrix,inducing the formation of dense and homogeneous hard domains that dissipated stress,prevented further crack devel-opment,and improved the mechanical properties and scratch resistance of the coating.In addition,the coating exhibited excellent self-healing properties.Fourier-transform infrared spectroscopy,scanning electron microscopy,and atomic force microscopy were used to characterize the self-healing and hardening mechanisms of the coating.The environmentally friendly PUU/KH-ND coating is easy to prepare and has broad application prospects in transparent and anti-scratch coatings for flexible electronics,automobiles,and home appliances.
文摘In this paper,the properties of different low-density heat-resistant coating prescriptions were compared,and a heat-resistant coating with a density of 0.65 g/cm^(3),a tensile strength of 2.04 MPa,and a thermal conductivity of 0.126 W/(m·K)was obtained.The thermal performance of the coating was characterized by an oxygen-acetylene ablation test,a hot radiation test using a quartz lamp and in an arc-heated wind tunnel test.The results indicated that the low-density heat-resistant coating prescription has advantages of high temperature resistance,erosion resistance,ablative resistance and excellent heat resistance,which can satisfy the heat resistance requirements of new-generation launch vehicle fairings.The successful application of this heat-resistant coating technology resolved the problems of low efficiency and poor adhesive performance of the traditional hand-pasted cork process,and realized the rapid spray application of the thermal protection layer,effectively improved the manufacturing efficiency and production quality of the heat-resistant layer of new-generation launch vehicle fairings.
文摘The objective of this review is to present the results on the production techniques, process parameters and compositions of heat-resistant coatings for graphite and carbon-carbon composites. The data reported concern the resistance of such protective coatings in air at temperatures up to 2273 K and in the high-speed flows of oxidizing gas media taking place in the spacecraft equipment. Coatings of this type, generally, have a multilayer structure based on the refractory compounds such as carbides, borides, silicides of transition metals and oxides with a high melting temperature. An efficient heat-resistant coating for carbon-based materials should be composed of three layers from which each fulfills its own function. The paper presents a new complex method for formation of heat-resistant coatings on the carbon-based materials. The method combines the vacuum-activated diffusion saturation in the presence of a liquid-phase and self-propagating high-temperature synthesis (SHS) simultaneously.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61078013 and J1103204)the Shanghai Pujiang Program,China (Grant No. 10PJ1401400)+1 种基金the National Basic Research Program of China (Grant Nos. 2011CB921604 and 2012CB921604)the Fudan University,China
文摘The linewidth of electromagnetically induced transparency（EIT） in a coated Rb vapor cell was studied under a magnetic field gradient.The nonlinear broadening of the EIT linewidth with the magnetic field gradient was observed.It was found that the motional averaging of the field gradient was more pronounced at higher laser intensities and larger beam sizes.In the same regime,there was a small linewidth decrease with the increasing magnetic field gradient.We have established a Monte-Carlo model,which gave results in good qualitative agreement with our experiment.Physics pictures for the above phenomena were also suggested.These results provide an understanding of the EIT linewidth behavior under motional averaging,and should be useful for applications in quantum optics and metrology based on coated vapor cells.
基金the National Natural Science Foundation of China(No.52108098)the Science,Technology and Innovation Commission of Shenzhen Municipality under a college supporting project(No.GXWD20201230155427003-20200731100557008).
文摘Transparent heat mirror which allows the transmission of visible sunlight while reflects the infrared thermal energy is an effective building energy efficiency technology for hot climatic regions.In this work,a five-layer dielectric/metal/dielectric/metal/dielectric(DMDMD)coating of Si_(3)N_(4)/Ag/Si_(3)N_(4)/Ag/Si_(3)N_(4)structure is proposed.The radiative properties of the five-layer coatings are theoretically investigated by transfer matrix method.The thicknesses of the layers are optimized by using particle swarm optimization method.The sample of the designed Si_(3)N_(4)/Ag/Si_(3)N_(4)/Ag/Si_(3)N_(4)coating is prepared and the building energy performance when applying the DMDMD coating in a simple office room is also investigated,taking the hot weather condition of Guangzhou,China as an example.The simulated results show that the Tave+Rave value of the five-layer coating is 8%higher than that of the three-layer coating,and the long-wave emittance of the five-layer coating is 24.8%lower than that of the three-layer coating.And the application of the five-layer coatings on the glazed window could provide the highest energy saving rate of 8.9%when compared with the traditional low-e coatings.
文摘Three coating methods (slot, dip and blade coatings) were used separately to coat a well-dispersed single-wall carbonnanotube (SWCNT) solution on polyethylene terephthalate (PET) film, and the resulting optical and electronic properties were measured and compared. It was found that the sheet resistance and the transparency of the SWCNT coated film decreased as the coating speed increased for dip and blade coatings, but were independent of the coating speed for slot coating. All three coating methods were able to produce transparent conductive film with transparency above 85% and sheet resistance close to 1000 ohm/sq. For industrial production, the slot die coating method appears to be more suitable in terms of high coating speed and uniformity of optical and electronic properties.
