The remodeling of axonal connections following injury is an important feature driving functional recovery.The reticulospinal tract is an interesting descending motor tract that contains both excitatory and inhibitory ...The remodeling of axonal connections following injury is an important feature driving functional recovery.The reticulospinal tract is an interesting descending motor tract that contains both excitatory and inhibitory fibers.While the reticulospinal tract has been shown to be particularly prone to axonal growth and plasticity following injuries of the spinal cord,the differential capacities of excitatory and inhibitory fibers for plasticity remain unclear.As adaptive axonal plasticity involves a sophisticated interplay between excitatory and inhibitory input,we investigated in this study the plastic potential of glutamatergic(vGlut2)and GABAergic(vGat)fibers originating from the gigantocellular nucleus and the lateral paragigantocellular nucleus,two nuclei important for locomotor function.Using a combination of viral tracing,chemogenetic silencing,and AI-based kinematic analysis,we investigated plasticity and its impact on functional recovery within the first 3 weeks following injury,a period prone to neuronal remodeling.We demonstrate that,in this time frame,while vGlut2-positive fibers within the gigantocellular and lateral paragigantocellular nuclei rewire significantly following cervical spinal cord injury,vGat-positive fibers are rather unresponsive to injury.We also show that the acute silencing of excitatory axonal fibers which rewire in response to lesions of the spinal cord triggers a worsening of the functional recovery.Using kinematic analysis,we also pinpoint the locomotion features associated with the gigantocellular nucleus or lateral paragigantocellular nucleus during functional recovery.Overall,our study increases the understanding of the role of the gigantocellular and lateral paragigantocellular nuclei during functional recovery following spinal cord injury.展开更多
Niobates are promising all-climate Li^(+)-storage anode material due to their fast charge transport,large specific capacities,and resistance to electrolyte reaction.However,their moderate unit-cellvolume expansion(gen...Niobates are promising all-climate Li^(+)-storage anode material due to their fast charge transport,large specific capacities,and resistance to electrolyte reaction.However,their moderate unit-cellvolume expansion(generally 5%–10%)during Li^(+)storage causes unsatisfactory long-term cyclability.Here,“zero-strain”NiNb_(2)O_(6) fibers are explored as a new anode material with comprehensively good electrochemical properties.During Li^(+)storage,the expansion of electrochemical inactive NiO_(6) octahedra almost fully offsets the shrinkage of active NbO_(6) octahedra through reversible O movement.Such superior volume-accommodation capability of the NiO_(6) layers guarantees the“zero-strain”behavior of NiNb_(2)O_(6) in a broad temperature range(0.53%//0.51%//0.74%at 25//−10//60℃),leading to the excellent cyclability of the NiNb_(2)O_(6) fibers(92.8%//99.2%//91.1%capacity retention after 1000//2000//1000 cycles at 10C and 25//−10//60℃).This NiNb_(2)O_(6) material further exhibits a large reversible capacity(300//184//318 mAh g−1 at 0.1C and 25//−10//60℃)and outstanding rate performance(10 to 0.5C capacity percentage of 64.3%//50.0%//65.4%at 25//−10//60℃).Therefore,the NiNb_(2)O_(6) fibers are especially suitable for large-capacity,fast-charging,long-life,and all-climate lithium-ion batteries.展开更多
Thorium dioxide(ThO_(2))fibers exhibit exceptional structural stability,low density and superior flexibility,coupled with a remarkably high melting point,positioning them as promising candidates for thermal protection...Thorium dioxide(ThO_(2))fibers exhibit exceptional structural stability,low density and superior flexibility,coupled with a remarkably high melting point,positioning them as promising candidates for thermal protection applications.Additionally,their commendable secondary processing characteristics enable the development of diverse composite materials when integrated with other materials,significantly broadening the potential utilization of ThO_(2)materials and thorium resources in industrial fields.In this work,the ThO_(2)fiber was fabricated by the sol-gel precursor method,and the precursor with good spinnability and excellent stability was synthesized for the first time.The ThO_(2)fiber with a mean diameter of 868 nm is both highly flexible and strong(max.tensile strength 2.21 MPa),capable of bending freely across a wide temperature range from-196℃(in liquid nitrogen)to 1200℃.Meanwhile,it exhibits excellent temperature stability and heat insulation properties.The ThO_(2)nanofiber membranes with layered structure have low density(32-37 mg·cm^(-3)),low thermal conductivity(27.3-30.1 mW·m^(-1)·K^(-1)@25℃).The ThO_(2)nanofiber membranes with 15 mm thickness can reduce the temperature from 1200 to 282℃and maintain a high aspect ratio and bendability after 1200℃@90 min.The results show that the ThO_(2)fiber can be used as a new kind of high-temperature resistant material.展开更多
Chemical vapor deposition is the predominant method to prepare MgAl_(2)O_(4)fibers.However,it faces several challenges,including exorbitantly high reaction temperatures,substantial production costs,and relatively low ...Chemical vapor deposition is the predominant method to prepare MgAl_(2)O_(4)fibers.However,it faces several challenges,including exorbitantly high reaction temperatures,substantial production costs,and relatively low yields.In this study,porous MgAl_(2)O_(4)fibers were fabricated through a solid-state reaction method,utilizing MgSO_(4)·5Mg(OH)_(2)·3H_(2)O whiskers as templates,mixed with either aluminum sol orα-Al_(2)O_(3)micropowder.The impact of various parameters on the synthesis of porous MgAl_(2)O_(4)fibres was systematically investigated,including the heat treatment temperature(1000,1100 and 1300℃),the holding time(3 and 10 h)and the aluminum source(aluminum sol orα-Al_(2)O_(3)micropowder).The results reveal that:(1)in comparison with fibers synthesized usingα-Al_(2)O_(3)as the aluminum source,those prepared with aluminum sol exhibit a significantly higher generation amount of MgAl_(2)O_(4);(2)as the heat treatment temperature increases,Al_(2)O_(3)gradually reacts with MgO,continuously increasing the formation amount of porous MgAl_(2)O_(4)with small and uniformly distributed nanopores,and the synthesized porous MgAl_(2)O_(4)fibres have small and uniform nanopores;(3)the optimal synthesis process involves using aluminum sol as the aluminum source and firing at 1300℃ for 3 h.展开更多
High-performance Ti_(3)C_(2)T_(x)fibers have garnered significant potential for smart fibers enabled fabrics.Nonetheless,a major challenge hindering their widespread use is the lack of strong interlayer interactions b...High-performance Ti_(3)C_(2)T_(x)fibers have garnered significant potential for smart fibers enabled fabrics.Nonetheless,a major challenge hindering their widespread use is the lack of strong interlayer interactions between Ti_(3)C_(2)T_(x)nanosheets within fibers,which restricts their properties.Herein,a versatile strategy is proposed to construct wet-spun Ti_(3)C_(2)T_(x)fibers,in which trace amounts of borate form strong interlayer crosslinking between Ti_(3)C_(2)T_(x)nanosheets to significantly enhance interactions as supported by density functional theory calculations,thereby reducing interlayer spacing,diminishing microscopic voids and promoting orientation of the nanosheets.The resultant Ti_(3)C_(2)T_(x)fibers exhibit exceptional electrical conductivity of 7781 S cm^(-1)and mechanical properties,including tensile strength of 188.72 MPa and Young's modulus of 52.42 GPa.Notably,employing equilibrium molecular dynamics simulations,finite element analysis,and cross-wire geometry method,it is revealed that such crosslinking also effectively lowers interfacial thermal resistance and ultimately elevates thermal conductivity of Ti_(3)C_(2)T_(x)fibers to 13 W m^(-1)K^(-1),marking the first systematic study on thermal conductivity of Ti_(3)C_(2)T_(x)fibers.The simple and efficient interlayer crosslinking enhancement strategy not only enables the construction of thermal conductivity Ti_(3)C_(2)T_(x)fibers with high electrical conductivity for smart textiles,but also offers a scalable approach for assembling other nanomaterials into multifunctional fibers.展开更多
To simultaneously improve the microwave absorption and thermal insulation properties of the ceramic materials for stealth high-speed vehicles,layered composites made of polymer-derived SiOC/ZrB_(2) rein-forced by ZrO_...To simultaneously improve the microwave absorption and thermal insulation properties of the ceramic materials for stealth high-speed vehicles,layered composites made of polymer-derived SiOC/ZrB_(2) rein-forced by ZrO_(2)/SiO_(2) fibers were reported in this work.The composites possess a continuous multilayer structure,which was fabricated via the precursor impregnation assisted by hot press curing and pyrolysis using the transparent ZrO_(2)/SiO_(2) fibers and polymer-derived SiOC and nano ZrB_(2).The layered composites show an effective absorption band(EAB)of 4.2 GHz at a thickness of 2.9 mm and a minimum reflection loss of-59.34 dB.The exceptional electromagnetic(EM)wave attenuation capability is ascribed to the impedance matching as well as massive EM wave loss caused by the multilayers in which the nano ZrB_(2) provides interfacial polarization and electrical conduction loss.With a design of the multi-curvature arch structure,a remarkable reduction of radar cross section can be achieved.Besides,the layered composites exhibit good oxidation resistance and thermal insulation when exposed to the dynamic heating environ-ment,demonstrating the potential application in harsh environments used for multifunctional electro-magnetic absorbing materials.展开更多
Cerium-doped SiO2/TiO2 nanostructured fibers were fabricated by electrospinning technology. The prepared fibers were characterized by thermogravimetric analysis （TGA）, scanning electron microscopy （SEM）, X-ray dif...Cerium-doped SiO2/TiO2 nanostructured fibers were fabricated by electrospinning technology. The prepared fibers were characterized by thermogravimetric analysis （TGA）, scanning electron microscopy （SEM）, X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FT-IR）. Using the fibers as catalysts, photoeatalytic degradation of Methylene Blue （MB） aqueous solution was carded out under simulated sunlight. The 0.2% Ce doping proved to be the optimal concentration for the doping of TiO2/SiO2, compared to other Ce-doped molar concentrations. The 0.2% Ce-doped SiOdTiO2 fibers exhibited higher photocatalytic activity than industrial Degussa P25 and the samples doped with only Ce or SIO2. The reasons for improving the photocatalytic activity were also discussed. Several operational parameters were studied, which showed that the photocatalytic efficiency of MB was influenced by parameters such as the initial dye concentration, the initial pH, inorganic anions, and so on. In addition, the influences of an electron acceptor and a radical scavenger suggested that OH was the dominant photooxidant during the photocatalytic process. The reuse evaluation of the fibers indicated that their photocatalytic activity had good stability.展开更多
Public safety incidents caused by bacterial infections have attracted widespread attention towards antibacterial textiles(fibers,fabrics,etc.).Nevertheless,it is still challenging to efficiently load inorganic nano-an...Public safety incidents caused by bacterial infections have attracted widespread attention towards antibacterial textiles(fibers,fabrics,etc.).Nevertheless,it is still challenging to efficiently load inorganic nano-antibacterial materials in polymer fibers.In this work,zirconium phosphate(ZrP,layered micro-nano materials)was utilized as a micro-nano carrier.The octadecyl triphenyl phosphonium bromide(OTP)was intercalated between the ZrP sheets by the ion exchange method to improve the carrier-polymer compatibility and the antibacterial performance.Through in-situ chemical reduction,the ultra-small nano-sized cuprous oxide(Cu_(2)O<5 nm)was loaded on the outer surface of ZrP to realize the uniform and stable dispersion of the Cu_(2)O on the carrier and improve the antibacterial performance.The ZrP nanosheets loaded with Cu_(2)O and OTP(Cu_(2)O@OZrP)had excellent antibacterial properties,and the antibacterial rate against E.coli,S.aureus and C.albicans was more than 99%.The intercalation amount of OTP in Cu_(2)O@OZrP can reach 16%,and the thermal stability was excellent and a significant increase in the Zeta potential.Indeed,the decomposition temperature was greater than 350℃,which was suitable for high-temperature melt processing of polymers.Consequently,we prepared PET/Cu_(2)O@OZrP fibers using polyethylene glycol terephthalate(PET),which accounts for 70%of the total chemical fibers,as the fiber matrix.PET/Cu_(2)O@OZrP fibers exhibited excellent mechanical property and antibacterial performance when the content of Cu_(2)O@OZrP was only 0.2%.The antibacterial rate against five types of bacteria including super bacteria(MRSA,VRE)was more than 99%.展开更多
Viscose-based activated carbon fibers （VACFs） were treated by a dielectric-barrier discharge plasma under the feed gas of N2. The surface functional groups of VACFs were modified to improve the adsorption and cataly...Viscose-based activated carbon fibers （VACFs） were treated by a dielectric-barrier discharge plasma under the feed gas of N2. The surface functional groups of VACFs were modified to improve the adsorption and catalysis capacity for SO2. The surface properties of the untreated and plasma-treated VACFs were diagnosed by SEM, BET, FTIR, and XPS, and the adsorption capacities of VACFs for SO2 were also compared and discussed. The results show that after the plasma treatment, the external surface of VACFs was etched and became rougher, while the surface area and the total pore volume decreased. FTIR and XPS revealed that nitrogen atoms were introduced onto the VACFs surface and the distribution of functional groups on the VACFs surface was changed remarkably. The adsorption characteristic of SO2 indicates that the plasmatreated VACFs have better adsorption capacity than the original VACFs due to the nitrogen functional groups and new functional groups formed in modification, which is beneficial to the adsorption of SO2.展开更多
The process of electrodepositing Fe-Cr2O3 composite coating on polyacrylonitrile （PAN）-based carbon fibers and its catalytic graphitization were studied. Carbon fibers with and without electrodeposited Fe-Cr2O3 comp...The process of electrodepositing Fe-Cr2O3 composite coating on polyacrylonitrile （PAN）-based carbon fibers and its catalytic graphitization were studied. Carbon fibers with and without electrodeposited Fe-Cr2O3 composite coating were heat treated at different temperatures and the structural changes were characterized by XRD, Raman spectroscopy and SEM. The results indicate that Fe-Cr2O3 composite coating exhibits a significant catalytic effect on graphitization of carbon fibers at low temperatures. When the Fe-Cr2O3-coated carbon fibers were heat treated at 1 300℃ the interlayer spacing （doo2） and ratio of relative peak area （AD/AG） reach 3.364/k and 0.34, respectively. Whereas, the extent of graphitization of pristine carbon fibers is comparatively low even after heat treatment at 2 800℃ and the values of doo2 and AD/AG are 3.414 A and 0.68, respectively. The extent of graphitization of carbon fibers increases not only with the increase of the catalyst gross but also the Cr2O3 content in Fe-Cr2O3 coating. The catalytic effect of Fe-Cr2O3 composite coating accords with the dissolution-precipitation mechanism.展开更多
The nanocomposite xCoFe2O4-(1-x)BaTiO3(x=0.2,0.3,0.4,0.5,molar fraction) fibers with fine diameters and high aspect ratios(length to diameter ratios) were prepared by the organic gel-thermal decomposition process from...The nanocomposite xCoFe2O4-(1-x)BaTiO3(x=0.2,0.3,0.4,0.5,molar fraction) fibers with fine diameters and high aspect ratios(length to diameter ratios) were prepared by the organic gel-thermal decomposition process from citric acid and metal salts.The structures and morphologies of gel precursors and fibers derived from thermal decomposition of the gel precursors were characterized by Fourier transform infrared spectroscopy,X-ray diffractometry and scanning electron microscopy.The magnetic properties of the nanocomposite fibers were measured by vibrating sample magnetometer.The nanocomposite fibers consisting of ferrite(CoFe2O4) and perovskite(BaTiO3) are formed at the calcination temperature of 900 ℃ for 2 h.The average grain sizes of CoFe2O4 and BaTiO3 in the nanocomposite fibers increase from 25 to 65 nm with the calcination temperature from 900 to 1 180 ℃.The single fiber constructed from these nanograins of CoFe2O4 and BaTiO3 has a necklace-like morphology.The saturation magnetization of the nanocomposite 0.4CoFe2O4-0.6BaTiO3 fibers increases with the increase of CoFe2O4 grain size,while the coercivity reaches a maximum value when the average grain size of CoFe2O4 is around the critical single-domain size of 45 nm obtained at 1 000 ℃.The saturation magnetization and remanence of the nanocomposite xCoFe2O4-(1-x)BaTiO3(x=0.2,0.3,0.4,0.5) fibers almost exhibit a linear relationship with the molar fraction of CoFe2O4 in the nanocomposites.展开更多
This work aimed at effectively utilizing the chemically depolymerized waste poly（ethylene terephthalate）（PET） fibers into useful products for the textile industry.PET fibers were glycolytically degraded by excess ...This work aimed at effectively utilizing the chemically depolymerized waste poly（ethylene terephthalate）（PET） fibers into useful products for the textile industry.PET fibers were glycolytically degraded by excess ethylene glycol as depolymerizing agent and zinc acetate dihydrate as catalyst.The glycolysis product,bis（2-hydroxyethyl） terephthalate（BHET）,was purified through repeated crystallization to get an average yield above 80%.Then,BHET was nitrated,reduced,and azotized to get diazonium salt.Finally,the produced diazonium salt was coupled with 1-（4-sulfophenyl）-3-methyl-5-pyrazolone to get azo dyestuff.The structures of BHET and azo dyestuff were identified by FT1 R and ^1H NMR spectra and elemental analysis.Nylon filaments dyed by the synthesized azo dyestuff with the dye bath pH from 4.14 to 5.88 showed bright yellow color.The performances of the dyestuff were described with dye uptake,color fastness,K/S,L^＊,a^＊,b^＊.and △E^＊ values.展开更多
A series of Ce, H3PW12O40 co-doped TiO2 hollow fibers photocatalysts have been prepared by sol-gel method using ammonium ceric nitrate, H3PW12O40 and tetrabutyltitanate as precursors and cotton fibers as template, fol...A series of Ce, H3PW12O40 co-doped TiO2 hollow fibers photocatalysts have been prepared by sol-gel method using ammonium ceric nitrate, H3PW12O40 and tetrabutyltitanate as precursors and cotton fibers as template, followed by calcination at 500 ℃ in N2 atmosphere for 2 h. Scanning electron microscopy, X-ray diffraction, nitrogen adsorption-desorption mea- surements, and UV-Vis spectroscopy are employed to characterize the morphology, crystal structure, surface structure, and optical absorption properties of the samples. The photo- catalytic performance of the samples has been studied by photodegradation phenol in water under UV and visible light irradiation. The results show that the TiO2 fiber materials have hollow structures, and the co-doped TiO2 hollow fibers exhibit higher photocatalytic activities for the degradation of phenol than un-doped, single-doped TiO2 hollow fibers under UV and visible light. In addition, the recyclability of co-doped TiO2 fibers is also confirmed that the TiO2 fiber retains ca. 90% of its activity after being used four times. It is shown that the co-doped TiO2 fibers can be activated by visible light and may be potentially applied to the treatment of water contaminated by organic pollutants. The synergistic effect of Ce and H3PW12O40 co-doping plays an important role in improving the photocatalytic activity.展开更多
2-D nanosheet Cu2O doped CuO coating poly m-phenylenediamine and melamine/graphene/carbon fibers composite(CuxO/MPM/GFs)was firstly fabricated by compound electrochemical method.CuxO/MPM/GFs was successfully used to t...2-D nanosheet Cu2O doped CuO coating poly m-phenylenediamine and melamine/graphene/carbon fibers composite(CuxO/MPM/GFs)was firstly fabricated by compound electrochemical method.CuxO/MPM/GFs was successfully used to the recovery of iodide(I-)from salt water by lower potential-aided sorption and desorption processes.The potential-aided recovery of I-at CuxO/MPM/GFs was characterized by FE-SEM,XRD,IR,Raman,XPS,UV-vis and electrochemical techniques in detail.The maximal adsorption capacity of 86.82 mg·g^-1 could be obtained with a pseudo-second-order model at 0.8 V for 210 min in pH 5.0,0.1 mol·L^-1 NaCl,and the process accompanied the generation of CuI,CuO and I5-.The I-could be quickly desorbed from the electrode with a transfer of CuI to Cu2O by cycle voltammetry from-1.0 to 0.5 V for 90 cycles in pH 9.0,0.1 mol·L^-1 KNO3.Thus,CuxO/MPM/GFs was renewable in the continuous electrochemical-adsorption-desorption processes.展开更多
基金supported by the Deutsche Forschungsgemeinschaft(DFG),TRR274(Project ID 408885537,Sy Nergy,EXC 2145/ID 390857198,to FMB)。
文摘The remodeling of axonal connections following injury is an important feature driving functional recovery.The reticulospinal tract is an interesting descending motor tract that contains both excitatory and inhibitory fibers.While the reticulospinal tract has been shown to be particularly prone to axonal growth and plasticity following injuries of the spinal cord,the differential capacities of excitatory and inhibitory fibers for plasticity remain unclear.As adaptive axonal plasticity involves a sophisticated interplay between excitatory and inhibitory input,we investigated in this study the plastic potential of glutamatergic(vGlut2)and GABAergic(vGat)fibers originating from the gigantocellular nucleus and the lateral paragigantocellular nucleus,two nuclei important for locomotor function.Using a combination of viral tracing,chemogenetic silencing,and AI-based kinematic analysis,we investigated plasticity and its impact on functional recovery within the first 3 weeks following injury,a period prone to neuronal remodeling.We demonstrate that,in this time frame,while vGlut2-positive fibers within the gigantocellular and lateral paragigantocellular nuclei rewire significantly following cervical spinal cord injury,vGat-positive fibers are rather unresponsive to injury.We also show that the acute silencing of excitatory axonal fibers which rewire in response to lesions of the spinal cord triggers a worsening of the functional recovery.Using kinematic analysis,we also pinpoint the locomotion features associated with the gigantocellular nucleus or lateral paragigantocellular nucleus during functional recovery.Overall,our study increases the understanding of the role of the gigantocellular and lateral paragigantocellular nuclei during functional recovery following spinal cord injury.
基金supported by the National Natural Science Foundation of China(51762014,52231007,12327804,T2321003,22088101)in part by the National Key Research Program of China under Grant 2021YFA1200600.
文摘Niobates are promising all-climate Li^(+)-storage anode material due to their fast charge transport,large specific capacities,and resistance to electrolyte reaction.However,their moderate unit-cellvolume expansion(generally 5%–10%)during Li^(+)storage causes unsatisfactory long-term cyclability.Here,“zero-strain”NiNb_(2)O_(6) fibers are explored as a new anode material with comprehensively good electrochemical properties.During Li^(+)storage,the expansion of electrochemical inactive NiO_(6) octahedra almost fully offsets the shrinkage of active NbO_(6) octahedra through reversible O movement.Such superior volume-accommodation capability of the NiO_(6) layers guarantees the“zero-strain”behavior of NiNb_(2)O_(6) in a broad temperature range(0.53%//0.51%//0.74%at 25//−10//60℃),leading to the excellent cyclability of the NiNb_(2)O_(6) fibers(92.8%//99.2%//91.1%capacity retention after 1000//2000//1000 cycles at 10C and 25//−10//60℃).This NiNb_(2)O_(6) material further exhibits a large reversible capacity(300//184//318 mAh g−1 at 0.1C and 25//−10//60℃)and outstanding rate performance(10 to 0.5C capacity percentage of 64.3%//50.0%//65.4%at 25//−10//60℃).Therefore,the NiNb_(2)O_(6) fibers are especially suitable for large-capacity,fast-charging,long-life,and all-climate lithium-ion batteries.
基金supported by the National Natural Science Foundation of China(No.52202090)the Fundamental Research Funds for the Central Universities(No.2082019014).
文摘Thorium dioxide(ThO_(2))fibers exhibit exceptional structural stability,low density and superior flexibility,coupled with a remarkably high melting point,positioning them as promising candidates for thermal protection applications.Additionally,their commendable secondary processing characteristics enable the development of diverse composite materials when integrated with other materials,significantly broadening the potential utilization of ThO_(2)materials and thorium resources in industrial fields.In this work,the ThO_(2)fiber was fabricated by the sol-gel precursor method,and the precursor with good spinnability and excellent stability was synthesized for the first time.The ThO_(2)fiber with a mean diameter of 868 nm is both highly flexible and strong(max.tensile strength 2.21 MPa),capable of bending freely across a wide temperature range from-196℃(in liquid nitrogen)to 1200℃.Meanwhile,it exhibits excellent temperature stability and heat insulation properties.The ThO_(2)nanofiber membranes with layered structure have low density(32-37 mg·cm^(-3)),low thermal conductivity(27.3-30.1 mW·m^(-1)·K^(-1)@25℃).The ThO_(2)nanofiber membranes with 15 mm thickness can reduce the temperature from 1200 to 282℃and maintain a high aspect ratio and bendability after 1200℃@90 min.The results show that the ThO_(2)fiber can be used as a new kind of high-temperature resistant material.
文摘Chemical vapor deposition is the predominant method to prepare MgAl_(2)O_(4)fibers.However,it faces several challenges,including exorbitantly high reaction temperatures,substantial production costs,and relatively low yields.In this study,porous MgAl_(2)O_(4)fibers were fabricated through a solid-state reaction method,utilizing MgSO_(4)·5Mg(OH)_(2)·3H_(2)O whiskers as templates,mixed with either aluminum sol orα-Al_(2)O_(3)micropowder.The impact of various parameters on the synthesis of porous MgAl_(2)O_(4)fibres was systematically investigated,including the heat treatment temperature(1000,1100 and 1300℃),the holding time(3 and 10 h)and the aluminum source(aluminum sol orα-Al_(2)O_(3)micropowder).The results reveal that:(1)in comparison with fibers synthesized usingα-Al_(2)O_(3)as the aluminum source,those prepared with aluminum sol exhibit a significantly higher generation amount of MgAl_(2)O_(4);(2)as the heat treatment temperature increases,Al_(2)O_(3)gradually reacts with MgO,continuously increasing the formation amount of porous MgAl_(2)O_(4)with small and uniformly distributed nanopores,and the synthesized porous MgAl_(2)O_(4)fibres have small and uniform nanopores;(3)the optimal synthesis process involves using aluminum sol as the aluminum source and firing at 1300℃ for 3 h.
基金the support from the National Natural Science Foundation of China(52403112,52473083)Natural Science Basic Research Program of Shaanxi(2024JC-TBZC-04)+2 种基金the Innovation Capability Support Program of Shaanxi(2024RS-CXTD-57)Fundamental Research Funds for the Central Universities(D5000240062,D5000240077)Undergraduate Innovation&Business Program in Northwestern Polytechnical University(202410699041)。
文摘High-performance Ti_(3)C_(2)T_(x)fibers have garnered significant potential for smart fibers enabled fabrics.Nonetheless,a major challenge hindering their widespread use is the lack of strong interlayer interactions between Ti_(3)C_(2)T_(x)nanosheets within fibers,which restricts their properties.Herein,a versatile strategy is proposed to construct wet-spun Ti_(3)C_(2)T_(x)fibers,in which trace amounts of borate form strong interlayer crosslinking between Ti_(3)C_(2)T_(x)nanosheets to significantly enhance interactions as supported by density functional theory calculations,thereby reducing interlayer spacing,diminishing microscopic voids and promoting orientation of the nanosheets.The resultant Ti_(3)C_(2)T_(x)fibers exhibit exceptional electrical conductivity of 7781 S cm^(-1)and mechanical properties,including tensile strength of 188.72 MPa and Young's modulus of 52.42 GPa.Notably,employing equilibrium molecular dynamics simulations,finite element analysis,and cross-wire geometry method,it is revealed that such crosslinking also effectively lowers interfacial thermal resistance and ultimately elevates thermal conductivity of Ti_(3)C_(2)T_(x)fibers to 13 W m^(-1)K^(-1),marking the first systematic study on thermal conductivity of Ti_(3)C_(2)T_(x)fibers.The simple and efficient interlayer crosslinking enhancement strategy not only enables the construction of thermal conductivity Ti_(3)C_(2)T_(x)fibers with high electrical conductivity for smart textiles,but also offers a scalable approach for assembling other nanomaterials into multifunctional fibers.
基金supported by the National Natural Science Foun-dation of China(Nos.52232005,52172104,and 52293370)the Fundamental Research Funds for the Central Universities(China,Nos.3102020QD0411 and D5000220152)the Creative Re-search Foundation of Science and Technology on Thermo-Structural Composite Materials Laboratory.
文摘To simultaneously improve the microwave absorption and thermal insulation properties of the ceramic materials for stealth high-speed vehicles,layered composites made of polymer-derived SiOC/ZrB_(2) rein-forced by ZrO_(2)/SiO_(2) fibers were reported in this work.The composites possess a continuous multilayer structure,which was fabricated via the precursor impregnation assisted by hot press curing and pyrolysis using the transparent ZrO_(2)/SiO_(2) fibers and polymer-derived SiOC and nano ZrB_(2).The layered composites show an effective absorption band(EAB)of 4.2 GHz at a thickness of 2.9 mm and a minimum reflection loss of-59.34 dB.The exceptional electromagnetic(EM)wave attenuation capability is ascribed to the impedance matching as well as massive EM wave loss caused by the multilayers in which the nano ZrB_(2) provides interfacial polarization and electrical conduction loss.With a design of the multi-curvature arch structure,a remarkable reduction of radar cross section can be achieved.Besides,the layered composites exhibit good oxidation resistance and thermal insulation when exposed to the dynamic heating environ-ment,demonstrating the potential application in harsh environments used for multifunctional electro-magnetic absorbing materials.
基金supported by the National Natural Science Foundation of China (No. 20907022,21003094)the Doctoral Program of Higher Education of China(No. 200800551003,20100032120066)the Special Projects of Environmental Protection (No. 2009ZX07526,2009ZX07208,200909101,2009GJA10021)
文摘Cerium-doped SiO2/TiO2 nanostructured fibers were fabricated by electrospinning technology. The prepared fibers were characterized by thermogravimetric analysis （TGA）, scanning electron microscopy （SEM）, X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FT-IR）. Using the fibers as catalysts, photoeatalytic degradation of Methylene Blue （MB） aqueous solution was carded out under simulated sunlight. The 0.2% Ce doping proved to be the optimal concentration for the doping of TiO2/SiO2, compared to other Ce-doped molar concentrations. The 0.2% Ce-doped SiOdTiO2 fibers exhibited higher photocatalytic activity than industrial Degussa P25 and the samples doped with only Ce or SIO2. The reasons for improving the photocatalytic activity were also discussed. Several operational parameters were studied, which showed that the photocatalytic efficiency of MB was influenced by parameters such as the initial dye concentration, the initial pH, inorganic anions, and so on. In addition, the influences of an electron acceptor and a radical scavenger suggested that OH was the dominant photooxidant during the photocatalytic process. The reuse evaluation of the fibers indicated that their photocatalytic activity had good stability.
基金This work was financially supported by the National Key Research and Development Program of China(Nos.2016YFA0201702 and 2016YFA0201700)the Program of Shanghai Academic/Technology Research Leader(No.20XD1433700)+2 种基金the International Cooperation Fund of the Science and Technology Commission of Shanghai Municipality(No.20520740800)the National Natural Science Foundation of China(Nos.51733002 and 52073047)China Postdoctoral Science Foundation(Nos.2019M661323 and 2020TQ0062)。
文摘Public safety incidents caused by bacterial infections have attracted widespread attention towards antibacterial textiles(fibers,fabrics,etc.).Nevertheless,it is still challenging to efficiently load inorganic nano-antibacterial materials in polymer fibers.In this work,zirconium phosphate(ZrP,layered micro-nano materials)was utilized as a micro-nano carrier.The octadecyl triphenyl phosphonium bromide(OTP)was intercalated between the ZrP sheets by the ion exchange method to improve the carrier-polymer compatibility and the antibacterial performance.Through in-situ chemical reduction,the ultra-small nano-sized cuprous oxide(Cu_(2)O<5 nm)was loaded on the outer surface of ZrP to realize the uniform and stable dispersion of the Cu_(2)O on the carrier and improve the antibacterial performance.The ZrP nanosheets loaded with Cu_(2)O and OTP(Cu_(2)O@OZrP)had excellent antibacterial properties,and the antibacterial rate against E.coli,S.aureus and C.albicans was more than 99%.The intercalation amount of OTP in Cu_(2)O@OZrP can reach 16%,and the thermal stability was excellent and a significant increase in the Zeta potential.Indeed,the decomposition temperature was greater than 350℃,which was suitable for high-temperature melt processing of polymers.Consequently,we prepared PET/Cu_(2)O@OZrP fibers using polyethylene glycol terephthalate(PET),which accounts for 70%of the total chemical fibers,as the fiber matrix.PET/Cu_(2)O@OZrP fibers exhibited excellent mechanical property and antibacterial performance when the content of Cu_(2)O@OZrP was only 0.2%.The antibacterial rate against five types of bacteria including super bacteria(MRSA,VRE)was more than 99%.
基金supported by National Natural Science Foundation of China(No.50876077)
文摘Viscose-based activated carbon fibers （VACFs） were treated by a dielectric-barrier discharge plasma under the feed gas of N2. The surface functional groups of VACFs were modified to improve the adsorption and catalysis capacity for SO2. The surface properties of the untreated and plasma-treated VACFs were diagnosed by SEM, BET, FTIR, and XPS, and the adsorption capacities of VACFs for SO2 were also compared and discussed. The results show that after the plasma treatment, the external surface of VACFs was etched and became rougher, while the surface area and the total pore volume decreased. FTIR and XPS revealed that nitrogen atoms were introduced onto the VACFs surface and the distribution of functional groups on the VACFs surface was changed remarkably. The adsorption characteristic of SO2 indicates that the plasmatreated VACFs have better adsorption capacity than the original VACFs due to the nitrogen functional groups and new functional groups formed in modification, which is beneficial to the adsorption of SO2.
基金Project(2006CB600903) supported by the National Basic Research Program of China
文摘The process of electrodepositing Fe-Cr2O3 composite coating on polyacrylonitrile （PAN）-based carbon fibers and its catalytic graphitization were studied. Carbon fibers with and without electrodeposited Fe-Cr2O3 composite coating were heat treated at different temperatures and the structural changes were characterized by XRD, Raman spectroscopy and SEM. The results indicate that Fe-Cr2O3 composite coating exhibits a significant catalytic effect on graphitization of carbon fibers at low temperatures. When the Fe-Cr2O3-coated carbon fibers were heat treated at 1 300℃ the interlayer spacing （doo2） and ratio of relative peak area （AD/AG） reach 3.364/k and 0.34, respectively. Whereas, the extent of graphitization of pristine carbon fibers is comparatively low even after heat treatment at 2 800℃ and the values of doo2 and AD/AG are 3.414 A and 0.68, respectively. The extent of graphitization of carbon fibers increases not only with the increase of the catalyst gross but also the Cr2O3 content in Fe-Cr2O3 coating. The catalytic effect of Fe-Cr2O3 composite coating accords with the dissolution-precipitation mechanism.
基金Project(50674048) supported by the National Natural Science Foundation of China Project(20080431069) supported by China Postdoctoral Science FoundationProject(CX10B-257Z) supported by Postgraduate Cultivation and Innovation Foundation of Jiangsu Province,China
文摘The nanocomposite xCoFe2O4-(1-x)BaTiO3(x=0.2,0.3,0.4,0.5,molar fraction) fibers with fine diameters and high aspect ratios(length to diameter ratios) were prepared by the organic gel-thermal decomposition process from citric acid and metal salts.The structures and morphologies of gel precursors and fibers derived from thermal decomposition of the gel precursors were characterized by Fourier transform infrared spectroscopy,X-ray diffractometry and scanning electron microscopy.The magnetic properties of the nanocomposite fibers were measured by vibrating sample magnetometer.The nanocomposite fibers consisting of ferrite(CoFe2O4) and perovskite(BaTiO3) are formed at the calcination temperature of 900 ℃ for 2 h.The average grain sizes of CoFe2O4 and BaTiO3 in the nanocomposite fibers increase from 25 to 65 nm with the calcination temperature from 900 to 1 180 ℃.The single fiber constructed from these nanograins of CoFe2O4 and BaTiO3 has a necklace-like morphology.The saturation magnetization of the nanocomposite 0.4CoFe2O4-0.6BaTiO3 fibers increases with the increase of CoFe2O4 grain size,while the coercivity reaches a maximum value when the average grain size of CoFe2O4 is around the critical single-domain size of 45 nm obtained at 1 000 ℃.The saturation magnetization and remanence of the nanocomposite xCoFe2O4-(1-x)BaTiO3(x=0.2,0.3,0.4,0.5) fibers almost exhibit a linear relationship with the molar fraction of CoFe2O4 in the nanocomposites.
基金financially supported by the National High-tech R&D Program of China(863 Program,No.2012AA030313)the Open Project Program of Key Laboratory of Eco-Textiles(Jiangnan University),Ministry of Education,China(No.KLET1115)+1 种基金the Fundamental Research Funds for the Central Universities(No. JUSRP11201)the Cooperative Innovation Fund-Prospective Project of Jiangsu Province,China(No.BY2012060)
文摘This work aimed at effectively utilizing the chemically depolymerized waste poly（ethylene terephthalate）（PET） fibers into useful products for the textile industry.PET fibers were glycolytically degraded by excess ethylene glycol as depolymerizing agent and zinc acetate dihydrate as catalyst.The glycolysis product,bis（2-hydroxyethyl） terephthalate（BHET）,was purified through repeated crystallization to get an average yield above 80%.Then,BHET was nitrated,reduced,and azotized to get diazonium salt.Finally,the produced diazonium salt was coupled with 1-（4-sulfophenyl）-3-methyl-5-pyrazolone to get azo dyestuff.The structures of BHET and azo dyestuff were identified by FT1 R and ^1H NMR spectra and elemental analysis.Nylon filaments dyed by the synthesized azo dyestuff with the dye bath pH from 4.14 to 5.88 showed bright yellow color.The performances of the dyestuff were described with dye uptake,color fastness,K/S,L^＊,a^＊,b^＊.and △E^＊ values.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.41373127） and Liaon- ing Provincial Natural Science Foundation of China （No.2013020121）.
文摘A series of Ce, H3PW12O40 co-doped TiO2 hollow fibers photocatalysts have been prepared by sol-gel method using ammonium ceric nitrate, H3PW12O40 and tetrabutyltitanate as precursors and cotton fibers as template, followed by calcination at 500 ℃ in N2 atmosphere for 2 h. Scanning electron microscopy, X-ray diffraction, nitrogen adsorption-desorption mea- surements, and UV-Vis spectroscopy are employed to characterize the morphology, crystal structure, surface structure, and optical absorption properties of the samples. The photo- catalytic performance of the samples has been studied by photodegradation phenol in water under UV and visible light irradiation. The results show that the TiO2 fiber materials have hollow structures, and the co-doped TiO2 hollow fibers exhibit higher photocatalytic activities for the degradation of phenol than un-doped, single-doped TiO2 hollow fibers under UV and visible light. In addition, the recyclability of co-doped TiO2 fibers is also confirmed that the TiO2 fiber retains ca. 90% of its activity after being used four times. It is shown that the co-doped TiO2 fibers can be activated by visible light and may be potentially applied to the treatment of water contaminated by organic pollutants. The synergistic effect of Ce and H3PW12O40 co-doping plays an important role in improving the photocatalytic activity.
基金supported by the National Natural Science Foundation of China(U1407110)Anhui Province Key Research and Development Plan(JZ2018AKKG0332)。
文摘2-D nanosheet Cu2O doped CuO coating poly m-phenylenediamine and melamine/graphene/carbon fibers composite(CuxO/MPM/GFs)was firstly fabricated by compound electrochemical method.CuxO/MPM/GFs was successfully used to the recovery of iodide(I-)from salt water by lower potential-aided sorption and desorption processes.The potential-aided recovery of I-at CuxO/MPM/GFs was characterized by FE-SEM,XRD,IR,Raman,XPS,UV-vis and electrochemical techniques in detail.The maximal adsorption capacity of 86.82 mg·g^-1 could be obtained with a pseudo-second-order model at 0.8 V for 210 min in pH 5.0,0.1 mol·L^-1 NaCl,and the process accompanied the generation of CuI,CuO and I5-.The I-could be quickly desorbed from the electrode with a transfer of CuI to Cu2O by cycle voltammetry from-1.0 to 0.5 V for 90 cycles in pH 9.0,0.1 mol·L^-1 KNO3.Thus,CuxO/MPM/GFs was renewable in the continuous electrochemical-adsorption-desorption processes.
