A high-activity and stable bifunctional oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)electrocatalyst is critical for seawater-based Zn-air batteries(ZABs).Herein,we report a wood-derived chainmail e...A high-activity and stable bifunctional oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)electrocatalyst is critical for seawater-based Zn-air batteries(ZABs).Herein,we report a wood-derived chainmail electrocatalyst containing defective nitrogen-doped carbon nanotubes encapsulating cobalt nanoparticles(Co@D-NCNT/CW)to enhance the ORR/OER activity and stability in seawater medium.During the preparation process,the introduction and removal of Zn increased the defect sites and pyridine N content in the carbon material,modulating charge distribution and influencing the adsorption and activation processes.The highly ordered open channels in Co@D-NCNT/CW promoted mass transfer of reactants and accelerated gas diffusion.The resultant chainmail electrocatalyst exhibited impressive bifunctional ORR and OER activities with an ultra-low gap of 0.67 V in sea water-based alkaline electrolyte.The Co@D-NCNT/CW-assembled seawater-based rechargeable liquid ZABs demonstrated a maximum power density of 245.3 mW cm^(-2)and a long-term cycling performance over 500 h.The seawater-based all-solid-state ZABs achieved the maximum power density of 48.2 mW cm^(-2)and stabilized over 30 h.Density functional theory revealed that the presence of defects and pyridine nitrogen in Co@D-NCNT/CW modulated the electronic structure of Co,optimizing the binding affinity of the Co sites with intermediates and weakening Cl^(-)adsorption.This work provides a new approach to preparing high-activity and stable ORR/OER electrocatalyst utilizing wood nanostructures,boosting the development of seawater-based ZABs.展开更多
Co_(3)O_(4)possesses both direct and indirect oxidation effects and is considered as a promising catalyst for the oxidation of 5-hydroxymethylfurfural(HMF).However,the enrichment and activation effects of Co_(3)O_(4)o...Co_(3)O_(4)possesses both direct and indirect oxidation effects and is considered as a promising catalyst for the oxidation of 5-hydroxymethylfurfural(HMF).However,the enrichment and activation effects of Co_(3)O_(4)on OH-and HMF are weak,which limits its further application.Metal defect engineering can regulate the electronic structure,optimize the adsorption of intermediates,and improve the catalytic activity by breaking the symmetry of the material,which is rarely involved in the upgrading of biomass.In this work,we prepare Co_(3)O_(4)with metal defects and load the precious metal platinum at the defect sites(PtVco).The results of in-situ characterizatio ns,electrochemical measurements,and theoretical calculations indicate that the reduction of Co-Co coordination number and the formation of Pt-Co bond induce the decrease of electron filling in the antibonding orbitals of Co element.The resulting upward shift of the d-band center of Co combined with the characteristic adsorption of Pt species synergically enhances the enrichment and activation of organic molecules and OH species,thus exhibiting excellent HMF oxidation activity(including a lower onset potential(1.14 V)and 19 times higher current density than pure Co_(3)O_(4)at 1.35 V).In summary,this work explores the adsorption enhancement mechanism of metal defect sites modified by precious metal in detail,provides a new option for improving the HMF oxidation activity of cobalt-based materials,broadens the application field of metal defect based materials,and gives an innovative guidance for the functional utilization of metal defect sites in biomass conversion.展开更多
In this study, polyethylene-terephthalate （PET） nonwovens are treated using an atmospheric plasma and the effects of the treatment time, treatment power and discharge distance on the ability of water-penetration int...In this study, polyethylene-terephthalate （PET） nonwovens are treated using an atmospheric plasma and the effects of the treatment time, treatment power and discharge distance on the ability of water-penetration into the nonwovens are investigated. The result indicates that the method can improve the wettability of PET nonwovens remarkably, but the aging decay of the sample＇s wettability is found to be notable as a function of the storage time after treatment due to the internal rotation of the single bond of surface macromolecules. As shown by SEM and XPS analysis, the etching and surface reaction are significant, and water-penetration weight is found to increase remarkably with the increasing power. This variation can be attributed to momentum transfer and enhanced higher-energy particle excitation.展开更多
The paper presents a detailed analysis of ordinary and dark energy density of the cosmos based on two different but complimentary theories. First, and starting from the concept of the speed of light being an average o...The paper presents a detailed analysis of ordinary and dark energy density of the cosmos based on two different but complimentary theories. First, and starting from the concept of the speed of light being an average over multi-fractals, we use Magueijo-Smolin’s ingenious revision of Einstein’s special relativity famous formula E = mc2 to a doubly special formula which includes the Planck energy as invariant to derive the ordinary energy density E(O) = mc2/22 and the dark energy density E(D) = mc2(21/22) wheremis the mass andcis the speed of light. Second we use the topological theory of pure gravity to reach the same result thus confirming the correctness of the theory of varying speed of light as well as the COBE, WMAP and Type 1a supernova cosmological measurements.展开更多
To overcome the ever-growing organic pollutions in the water system,abundant efforts have been dedicated to fabricating efficient Fenton-like carbon catalysts.However,the rational design of carbon catalysts with high ...To overcome the ever-growing organic pollutions in the water system,abundant efforts have been dedicated to fabricating efficient Fenton-like carbon catalysts.However,the rational design of carbon catalysts with high intrinsic activity remains a long-term goal.Herein,we report a new N-molecule-assisted self-catalytic carbonization process in augmenting the intrinsic Fenton-like activity of metal-organic-framework-derived carbon hybrids.During carbonization,the N-molecules provide alkane/ammonia gases and the formed iron nanocrystals act as the in situ catalysts,which result in the elaborated formation of carbon nanotubes(in situ chemical vapor deposition from alkane/iron catalysts)and micro-/meso-porous structures(ammonia gas etching).The obtained catalysts exhibited with abundant Fe/Fe-Nx/pyridinic-N active species,micro-/meso-porous structures,and conductive carbon nanotubes.Consequently,the catalysts exhibit high efficiency toward the degradation of different organic pollutions,such as bisphenol A,methylene blue,and tetracycline.This study not only creates a new pathway for achieving highly active Fenton-like carbon catalysts but also takes a step toward the customized production of advanced carbon hybrids for diverse energy and environmental applications.展开更多
Recently,in response to the major challenges in energy development and environmental issues,tremendous efforts are being devoted to developing electrochemical energy storage devices based on green sustainable resource...Recently,in response to the major challenges in energy development and environmental issues,tremendous efforts are being devoted to developing electrochemical energy storage devices based on green sustainable resources.As a class of green materials,nanocellulose(NC)has received extensive attention.In this review,we summarize the research progress of NC derived materials in electrochemical energy storage.Specifically,we first introduce various synthesis methods based on NC and the pretreatment process to increase the conductivity.Then we focus on the specific application of NC in electrochemical energy storage devices.Finally,we summarize the previously reported work and put forward views on the further development of NC in the field of electrochemical energy storage.展开更多
A heterojunction photoanode of Fe2O3 loaded on a WO3 film on a fluorine-doped tin oxide substrate(FTO-WO3/Fe2O3)was prepared via a simple hydrothermal and chemical vapor deposition(CVD)growth method.The photoanode sho...A heterojunction photoanode of Fe2O3 loaded on a WO3 film on a fluorine-doped tin oxide substrate(FTO-WO3/Fe2O3)was prepared via a simple hydrothermal and chemical vapor deposition(CVD)growth method.The photoanode showed higher photoelectrochemical(PEC)water-splitting activity than that of the pristine FTO-WO3 under simulated sunlight because of the synergistic effect of Fe2O3 and WO3.The as-synthesized material was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).The photocurrent density was estimated by linear sweep voltammetry and further confirmed using intensity-modulated photocurrent spectra.Experiments demonstrated that the coated Fe2O3 enhanced the separation and migration efficiencies of the photoinduced electrons and holes,improving the PEC water-splitting properties.The FTO-WO3/Fe2O3 photoanode showed a 1.25 times enhancement in photocurrent density compared with FTO-WO3.This result suggests that facile chemical vapor deposition growth is an effective way to fabricate heterojunctions and improve the properties of WO3 photoanodes for PEC water-splitting applications.展开更多
We collect 1974 broad-band velocity records of 94 earthquakes (ML=2.84.9, △=13462 km) from seven stations of the Fujian Seismic Network from March 1999 to March 2007. Using real-time simulation, we obtain the corresp...We collect 1974 broad-band velocity records of 94 earthquakes (ML=2.84.9, △=13462 km) from seven stations of the Fujian Seismic Network from March 1999 to March 2007. Using real-time simulation, we obtain the corresponding acceleration and then adopt different models to analyze the seismic data. As a result, a new attenuation relationship between PGA and PGV of the small and moderate earthquakes on bedrock site in Fujian region is established. The Yongchun earthquake occurred recently verifies the attenuation relationship well. This paper provides a new approach for studying the ground motion attenuation relationship using velocity records.展开更多
Membrane-based separation processes are new technology combined membrane separation with conventional separation. Hydrophobic porous membranes are often used in these processes. The structure of hydrophobic porous mem...Membrane-based separation processes are new technology combined membrane separation with conventional separation. Hydrophobic porous membranes are often used in these processes. The structure of hydrophobic porous membrane has significant effect on mass transfer process. The permeabilities of five kinds of gas, He, N2, O2, CO2 and water vapor, across six polytetrafluoroethylene(PTFE) flat membranes were tested experimentally. Results indicated that the greater the membrane mean pore size and the wider the pore size distribution are, the higher the gas permeability. A gas permeation model, including the effects of membrane structure parameter and gas properties, was established. A comprehensive characteristic parameter (including porosity, thickness and tortuosity) was found more effective to express the influence of membrane structure in gas permeation process. The predicted permeation coefficients were in good agreement with experimental data.展开更多
Layered double hydroxides(LDHs)have a special structure and atom composition,which are expected to be an excellent electromagnetic wave(EMW)absorber.However,it is still a problem that obtaining excellent EMWabsorbing ...Layered double hydroxides(LDHs)have a special structure and atom composition,which are expected to be an excellent electromagnetic wave(EMW)absorber.However,it is still a problem that obtaining excellent EMWabsorbing materials from LDHs.Herein,we designed heterostructure NiCo-LDHs@ZnO nanorod and then subsequent heat treating to derive NiCo@C/ZnO composites.Finally,with the synergy of excellent dielectric loss and magnetic loss,an outstanding absorption performance could be achieved with the reflection loss of−60.97 dB at the matching thickness of 2.3 mm,and the widest absorption bandwidth of 6.08 GHz was realized at 2.0 mm.Moreover,this research work provides a reference for the development and utilization of LDHs materials in the field of microwave absorption materials and can also provide ideas for the design of layered structural absorbers.展开更多
The phenomenon of a material failure varies with its gauge length in use. In the present study, the breaking strengths of J30/C70 and J55/C45 blended yarns spun by the ring spinning technology were investigated with ...The phenomenon of a material failure varies with its gauge length in use. In the present study, the breaking strengths of J30/C70 and J55/C45 blended yarns spun by the ring spinning technology were investigated with the employment of the equations derived from the Weibull theory. The four probability estimators of the Weibull distribution were also evaluated. The results showed that the estimator （2a） was acceptable for calculating the Weibull modulus of the jute/cotton blended yarns. With the exception of breaking strength of the J30/C70 at the gauge length of 200 ram, the breaking strengths of both blended yarn could be predicted accurately by the Eqs. （9） or （10） in this paper.展开更多
Electrocatalytic carbon dioxide(CO_(2))reduction is an important way to achieve carbon neutrality by converting CO_(2)in-to high-value-added chemicals using electric energy.Carbon-based materials are widely used in va...Electrocatalytic carbon dioxide(CO_(2))reduction is an important way to achieve carbon neutrality by converting CO_(2)in-to high-value-added chemicals using electric energy.Carbon-based materials are widely used in various electrochemical reactions,including electrocatalytic CO_(2)reduction,due to their low cost and high activity.In recent years,defect engineering has attracted wide attention by constructing asymmetric defect centers in the materials,which can optimize the physicochemical properties of the mater-ial and improve its electrocatalytic activity.This review summarizes the types,methods of formation and defect characterization tech-niques of defective carbon-based materials.The advantages of defect engineering and the advantages and disadvantages of various defect formation methods and characterization techniques are also evaluated.Finally,the challenges of using defective carbon-based materials in electrocatalytic CO_(2)reduction are investigated and opportunities for their use are discussed.It is believed that this re-view will provide suggestions and guidance for developing defective carbon-based materials for CO_(2)reduction.展开更多
Water splitting,as an advanced energy conversion technology,consists of two half reactions,including oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).However,the ideal electrocatalysts are noble meta...Water splitting,as an advanced energy conversion technology,consists of two half reactions,including oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).However,the ideal electrocatalysts are noble metal based catalysts.Their high cost and scarcity in earth seriously restrict the large deployments.Ni Fe-based materials have attracted great attention in recent years due to their excellent catalytic properties for OER and HER.Nevertheless,their conductivity and electrochemical stability at high current density are unsatisfactory,resulting in ineffective water splitting due to high impedance and low stability.Recently,a series of catalysts coating Ni Fe-based materials on 3 D nickel foam were found to be extremely stable under the circumstance of high current density.In this review,we summarized the recent advances of NiFe-based materials on nickel foam for OER and HER,respectively,and further provided the perspectives for their future development.展开更多
Background:The few previous studies that focused on the effects of compression garments(CG)on distance running performance have simultaneously measured electromyogram,physiological,and perceptual parameters.Therefore,...Background:The few previous studies that focused on the effects of compression garments(CG)on distance running performance have simultaneously measured electromyogram,physiological,and perceptual parameters.Therefore,this study investigated the effects of CG on muscle activation and median frequency during and after distance running,as well as blood-lactate concentration and rating of perceived exertion(RPE)during distance running.Methods:Eight healthy male recreational runners were recruited to randomly perform two 40 min treadmill running trials,one with CG,and the other with control garment made of normal cloth.The RPE and the surface electromyography(EMG)of 5 lower extremity muscles including gluteus maximus(GM),rectus femoris(RF),semitendinosus(ST),tibialis anterior(TA),and gastrocnemius(GAS)were measured during the running trial.The blood-lactate levels before and after the running trial were measured.Results:Wearing CG led to significant lower muscle activation(p<0.05)in the GM(decreased 7.40%-14.31%),RF(decreased 4.39%-4.76%),and ST(decreased 3.42%-7.20%)muscles;moreover,significant higher median frequency(p<0.05)in the GM(increased 5.57%)and ST(increased 10.58%)muscles.Wearing CG did not alter the RPE values or the blood-lactate levels(p>0.05).Conclusion:Wearing CG was associated with significantly lower muscle activation and higher median frequency in the running-related key muscles during distance running.This finding suggested that wearing CG may improve muscle function,which might enhance running performance and prevent muscle fatigue.展开更多
Waterborne elastic polyester (WEP) with different content of hard polyester was applied in the maize starch (MS) based composites (MS/WEP) via solution casting method.The effects of WEP with different contents of hard...Waterborne elastic polyester (WEP) with different content of hard polyester was applied in the maize starch (MS) based composites (MS/WEP) via solution casting method.The effects of WEP with different contents of hard polyester on the structure and properties of starch were studied by Fourier transform infrared,X-ray diffraction,ultraviolet-visible,tensile test,differential scanning calorimeter,thermogravimetric analysis and moisture measurement.The experimental results show that the addition of WEP does not change the crystalline type of starch,and only reduces the crystallinity of starch.And the structure and properties of MS/WEP are related to not only the content of starch but also the microstructure of WEP or the content of hard polyester in WEP.Waterborne elastic polyester with 30wt% hard polyester (WEP30) has the best modification effect on the maize starch among all the WEPs.For example,MS/WEP30 film has the optimum toughness,aging resistance and transmittance,the lowest crystallinity and glass transition temperature among all the MS/WEP films,and the lower moisture content.It is related to the compatibility between starch and WEP,resulting from the number of physical crosslinking points in WEP..展开更多
A microscope method was developed for testing the blending ratio of akund/cotton blended yarns. Fiber characteristics such as diameter, longitudinal feature, and hollow structure were observed to identify akund and co...A microscope method was developed for testing the blending ratio of akund/cotton blended yarns. Fiber characteristics such as diameter, longitudinal feature, and hollow structure were observed to identify akund and cotton. Therefore, the measurement of the blending ratio for akund/cotton blended yarns based on each fiber's amount, moisture regain, and metric count was available. The results show that using specimen's longitudinal section is more effective during the fiber counting than specimen's transverse section benefiting from the separation of the fibers.展开更多
The effects of coagulation conditions on tensile properties of the regenerated cellulose fibers prepared by wet-spinning from NaOH/thiourea/urea(8∶6.5∶8 by weight)aqueous solvent were investigated by tensile tester,...The effects of coagulation conditions on tensile properties of the regenerated cellulose fibers prepared by wet-spinning from NaOH/thiourea/urea(8∶6.5∶8 by weight)aqueous solvent were investigated by tensile tester,X-ray diffraction(XRD),and scanning electron microscope(SEM).The results show that the tensile properties of the as-spun fibers change with the coagualtion concentration,temperature,and time.When the spinning solution is coagulated in 10% H2SO4/12.5% Na2SO4 aqueous solution,the as-spun fibers have a typical structure of cellulose II,a circular cross-section,and homogeneous morphological structure.展开更多
Cellulose pulps were directly dissolved in a green solvent of sodium hydrate/urea/thiourea/water with different composition for the purpose to prepare new regenerated cellulose fibers or films. The results showed that...Cellulose pulps were directly dissolved in a green solvent of sodium hydrate/urea/thiourea/water with different composition for the purpose to prepare new regenerated cellulose fibers or films. The results showed that the highest solubility of cellulose in the solvent with the composition of 8/8/6.5/77.5. The results revealed that the pulp feeding sequence, stirring rate, pre-treatment of pulp and pulp size affected the cellulose concentration in the green solvent. Accordingly, the more effective dissolution method was proposed in order to get higher concentration of cellulose. Furthermore, the properties of solution prepared by different kinds of pulps in the solvent were investigated by ARES rheometer. Rheologieal analyses indicated that all cellulose aqueous solutions in their high concentration were pseudoplastic fluids and sensitive to temperature and tended to transform to gel when temperature increased.展开更多
A series of segmented polyether-polyester polyurethane with amorphous hydrophilic soft segment domains were prepared from 4,4'- diphenylmethane diisocyanate (MDI), polybutylene adipate (Glycol) 2000 (PBA2000), and...A series of segmented polyether-polyester polyurethane with amorphous hydrophilic soft segment domains were prepared from 4,4'- diphenylmethane diisocyanate (MDI), polybutylene adipate (Glycol) 2000 (PBA2000), and polyethylene glycol 1000 (PEG1000), with 1,4-butanediol (BDO) as the chain extender. Furthermore, several representative properties of the polyurethanes, such as moisture permeability, water resistance, hydrophilic property, and phase inversion temperature, were investigated. The studies show that the structure and concentration of soft segment have a remarkable effect on the main application properties of polyurethane. On the contrary, the functional properties of the polyurethane are almost not affected by its hard segment.展开更多
Without any preprocessing,polyester fabric has lower ability to hold on water and inks due to the smooth morphology of polyester fibers. Therefore, patterns directly printed with pigment inks have poor color yields an...Without any preprocessing,polyester fabric has lower ability to hold on water and inks due to the smooth morphology of polyester fibers. Therefore, patterns directly printed with pigment inks have poor color yields and bleed easily. Pretreatments of polyester fabric were carried out with atmospheric air plasma under different experimental conditions. After plasma treatment the samples were printed with magenta pigment ink. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses indicated that the enhanced color performance was mainly contributed by not only the etching effect but also oxygen-containing polar groups induced onto fiber surfaces through plasma treatment. Thereby the surface modification of polyester fabrics using atmospheric-pressure air plasma offers a potential way to fabric pretreatment for pigment inkjet printing with the advantages of environmental friendly and energy saving over traditional pretreatment methods.展开更多
基金financial support by the Excellent Youth Foundation of Shandong Province(No.ZR2022YQ22)National Natural Science Foundation of China(No.32101451)Youth Innovation Team Project of Shandong Province(No.2022KJ303)。
文摘A high-activity and stable bifunctional oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)electrocatalyst is critical for seawater-based Zn-air batteries(ZABs).Herein,we report a wood-derived chainmail electrocatalyst containing defective nitrogen-doped carbon nanotubes encapsulating cobalt nanoparticles(Co@D-NCNT/CW)to enhance the ORR/OER activity and stability in seawater medium.During the preparation process,the introduction and removal of Zn increased the defect sites and pyridine N content in the carbon material,modulating charge distribution and influencing the adsorption and activation processes.The highly ordered open channels in Co@D-NCNT/CW promoted mass transfer of reactants and accelerated gas diffusion.The resultant chainmail electrocatalyst exhibited impressive bifunctional ORR and OER activities with an ultra-low gap of 0.67 V in sea water-based alkaline electrolyte.The Co@D-NCNT/CW-assembled seawater-based rechargeable liquid ZABs demonstrated a maximum power density of 245.3 mW cm^(-2)and a long-term cycling performance over 500 h.The seawater-based all-solid-state ZABs achieved the maximum power density of 48.2 mW cm^(-2)and stabilized over 30 h.Density functional theory revealed that the presence of defects and pyridine nitrogen in Co@D-NCNT/CW modulated the electronic structure of Co,optimizing the binding affinity of the Co sites with intermediates and weakening Cl^(-)adsorption.This work provides a new approach to preparing high-activity and stable ORR/OER electrocatalyst utilizing wood nanostructures,boosting the development of seawater-based ZABs.
基金financially supported by the Natural Science Foundation of Shandong Province(ZR2023QB235,ZR202111240183,ZR2021QF120)the Postdoctoral Science Foundation of China(2022M711956)the Taishan Scholar Program of Shandong Province(tsqnz20231216).
文摘Co_(3)O_(4)possesses both direct and indirect oxidation effects and is considered as a promising catalyst for the oxidation of 5-hydroxymethylfurfural(HMF).However,the enrichment and activation effects of Co_(3)O_(4)on OH-and HMF are weak,which limits its further application.Metal defect engineering can regulate the electronic structure,optimize the adsorption of intermediates,and improve the catalytic activity by breaking the symmetry of the material,which is rarely involved in the upgrading of biomass.In this work,we prepare Co_(3)O_(4)with metal defects and load the precious metal platinum at the defect sites(PtVco).The results of in-situ characterizatio ns,electrochemical measurements,and theoretical calculations indicate that the reduction of Co-Co coordination number and the formation of Pt-Co bond induce the decrease of electron filling in the antibonding orbitals of Co element.The resulting upward shift of the d-band center of Co combined with the characteristic adsorption of Pt species synergically enhances the enrichment and activation of organic molecules and OH species,thus exhibiting excellent HMF oxidation activity(including a lower onset potential(1.14 V)and 19 times higher current density than pure Co_(3)O_(4)at 1.35 V).In summary,this work explores the adsorption enhancement mechanism of metal defect sites modified by precious metal in detail,provides a new option for improving the HMF oxidation activity of cobalt-based materials,broadens the application field of metal defect based materials,and gives an innovative guidance for the functional utilization of metal defect sites in biomass conversion.
文摘In this study, polyethylene-terephthalate （PET） nonwovens are treated using an atmospheric plasma and the effects of the treatment time, treatment power and discharge distance on the ability of water-penetration into the nonwovens are investigated. The result indicates that the method can improve the wettability of PET nonwovens remarkably, but the aging decay of the sample＇s wettability is found to be notable as a function of the storage time after treatment due to the internal rotation of the single bond of surface macromolecules. As shown by SEM and XPS analysis, the etching and surface reaction are significant, and water-penetration weight is found to increase remarkably with the increasing power. This variation can be attributed to momentum transfer and enhanced higher-energy particle excitation.
文摘The paper presents a detailed analysis of ordinary and dark energy density of the cosmos based on two different but complimentary theories. First, and starting from the concept of the speed of light being an average over multi-fractals, we use Magueijo-Smolin’s ingenious revision of Einstein’s special relativity famous formula E = mc2 to a doubly special formula which includes the Planck energy as invariant to derive the ordinary energy density E(O) = mc2/22 and the dark energy density E(D) = mc2(21/22) wheremis the mass andcis the speed of light. Second we use the topological theory of pure gravity to reach the same result thus confirming the correctness of the theory of varying speed of light as well as the COBE, WMAP and Type 1a supernova cosmological measurements.
基金supported by the National Key R&D Program of China(2019YFA0110600 and 2019YFA0110601)National Natural Science Foundation of China(Nos.51603134,51903178,51803134,and 51703141)+1 种基金Sichuan Province’s Science and Technology Planning Project(No.2016GZ0350)the Postgraduate Course Construction Project of Sichuan University(No.2017KCSJ036)and for their financial support.
文摘To overcome the ever-growing organic pollutions in the water system,abundant efforts have been dedicated to fabricating efficient Fenton-like carbon catalysts.However,the rational design of carbon catalysts with high intrinsic activity remains a long-term goal.Herein,we report a new N-molecule-assisted self-catalytic carbonization process in augmenting the intrinsic Fenton-like activity of metal-organic-framework-derived carbon hybrids.During carbonization,the N-molecules provide alkane/ammonia gases and the formed iron nanocrystals act as the in situ catalysts,which result in the elaborated formation of carbon nanotubes(in situ chemical vapor deposition from alkane/iron catalysts)and micro-/meso-porous structures(ammonia gas etching).The obtained catalysts exhibited with abundant Fe/Fe-Nx/pyridinic-N active species,micro-/meso-porous structures,and conductive carbon nanotubes.Consequently,the catalysts exhibit high efficiency toward the degradation of different organic pollutions,such as bisphenol A,methylene blue,and tetracycline.This study not only creates a new pathway for achieving highly active Fenton-like carbon catalysts but also takes a step toward the customized production of advanced carbon hybrids for diverse energy and environmental applications.
基金financial support by the National Natural Science Foundation of China(grant no.51808303,51672143 and 31870535)Outstanding Youth of Natural Science in Shandong Province(JQ201713)Taishan Scholars Program and ARC Discovery Project(No.170103317)。
文摘Recently,in response to the major challenges in energy development and environmental issues,tremendous efforts are being devoted to developing electrochemical energy storage devices based on green sustainable resources.As a class of green materials,nanocellulose(NC)has received extensive attention.In this review,we summarize the research progress of NC derived materials in electrochemical energy storage.Specifically,we first introduce various synthesis methods based on NC and the pretreatment process to increase the conductivity.Then we focus on the specific application of NC in electrochemical energy storage devices.Finally,we summarize the previously reported work and put forward views on the further development of NC in the field of electrochemical energy storage.
基金financially supported by the National Natural Science Foundation of China(Nos.51672143 and 51808303)Shandong Province Natural Science Foundation(ZR2019BEE027,ZR2017MEM018,ZR2018BEM002)+2 种基金Taishan Scholars Program of Shandong ProvinceOutstanding Youth of Natural Science in Shandong Province(JQ201713)Australian Research Council Discovery Project(No.170103317)。
文摘A heterojunction photoanode of Fe2O3 loaded on a WO3 film on a fluorine-doped tin oxide substrate(FTO-WO3/Fe2O3)was prepared via a simple hydrothermal and chemical vapor deposition(CVD)growth method.The photoanode showed higher photoelectrochemical(PEC)water-splitting activity than that of the pristine FTO-WO3 under simulated sunlight because of the synergistic effect of Fe2O3 and WO3.The as-synthesized material was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).The photocurrent density was estimated by linear sweep voltammetry and further confirmed using intensity-modulated photocurrent spectra.Experiments demonstrated that the coated Fe2O3 enhanced the separation and migration efficiencies of the photoinduced electrons and holes,improving the PEC water-splitting properties.The FTO-WO3/Fe2O3 photoanode showed a 1.25 times enhancement in photocurrent density compared with FTO-WO3.This result suggests that facile chemical vapor deposition growth is an effective way to fabricate heterojunctions and improve the properties of WO3 photoanodes for PEC water-splitting applications.
基金Joint Seismological Science Foundation of China (105034)
文摘We collect 1974 broad-band velocity records of 94 earthquakes (ML=2.84.9, △=13462 km) from seven stations of the Fujian Seismic Network from March 1999 to March 2007. Using real-time simulation, we obtain the corresponding acceleration and then adopt different models to analyze the seismic data. As a result, a new attenuation relationship between PGA and PGV of the small and moderate earthquakes on bedrock site in Fujian region is established. The Yongchun earthquake occurred recently verifies the attenuation relationship well. This paper provides a new approach for studying the ground motion attenuation relationship using velocity records.
基金Supported by the 863 Hi-Tech. Research and Development Program of China (No. 2002AA649280, No. 2002AA304030),National Natural Science Foundation of China (No. 20206002), Beijing NOVA program (H013610250112), University Doctor Science Foundation of China
文摘Membrane-based separation processes are new technology combined membrane separation with conventional separation. Hydrophobic porous membranes are often used in these processes. The structure of hydrophobic porous membrane has significant effect on mass transfer process. The permeabilities of five kinds of gas, He, N2, O2, CO2 and water vapor, across six polytetrafluoroethylene(PTFE) flat membranes were tested experimentally. Results indicated that the greater the membrane mean pore size and the wider the pore size distribution are, the higher the gas permeability. A gas permeation model, including the effects of membrane structure parameter and gas properties, was established. A comprehensive characteristic parameter (including porosity, thickness and tortuosity) was found more effective to express the influence of membrane structure in gas permeation process. The predicted permeation coefficients were in good agreement with experimental data.
基金financially supported by the National Natural Science Foundation of China(No.51407134)Natural Science Foundation of Shandong Province(No.ZR2019YQ24)+3 种基金Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)China Postdoctoral Science Foundation(No.2016M590619)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites)The authors acknowledge the support from The Thousand Talents Plan,The World-Class University and Discipline,The Taishan Scholar’s Advantageous and Distinctive Discipline Program of Shandong Province and The World-Class Discipline Program of Shandong Province.
文摘Layered double hydroxides(LDHs)have a special structure and atom composition,which are expected to be an excellent electromagnetic wave(EMW)absorber.However,it is still a problem that obtaining excellent EMWabsorbing materials from LDHs.Herein,we designed heterostructure NiCo-LDHs@ZnO nanorod and then subsequent heat treating to derive NiCo@C/ZnO composites.Finally,with the synergy of excellent dielectric loss and magnetic loss,an outstanding absorption performance could be achieved with the reflection loss of−60.97 dB at the matching thickness of 2.3 mm,and the widest absorption bandwidth of 6.08 GHz was realized at 2.0 mm.Moreover,this research work provides a reference for the development and utilization of LDHs materials in the field of microwave absorption materials and can also provide ideas for the design of layered structural absorbers.
基金National Key Technologies R&D Programof China (No.2007BAE41B01)
文摘The phenomenon of a material failure varies with its gauge length in use. In the present study, the breaking strengths of J30/C70 and J55/C45 blended yarns spun by the ring spinning technology were investigated with the employment of the equations derived from the Weibull theory. The four probability estimators of the Weibull distribution were also evaluated. The results showed that the estimator （2a） was acceptable for calculating the Weibull modulus of the jute/cotton blended yarns. With the exception of breaking strength of the J30/C70 at the gauge length of 200 ram, the breaking strengths of both blended yarn could be predicted accurately by the Eqs. （9） or （10） in this paper.
文摘Electrocatalytic carbon dioxide(CO_(2))reduction is an important way to achieve carbon neutrality by converting CO_(2)in-to high-value-added chemicals using electric energy.Carbon-based materials are widely used in various electrochemical reactions,including electrocatalytic CO_(2)reduction,due to their low cost and high activity.In recent years,defect engineering has attracted wide attention by constructing asymmetric defect centers in the materials,which can optimize the physicochemical properties of the mater-ial and improve its electrocatalytic activity.This review summarizes the types,methods of formation and defect characterization tech-niques of defective carbon-based materials.The advantages of defect engineering and the advantages and disadvantages of various defect formation methods and characterization techniques are also evaluated.Finally,the challenges of using defective carbon-based materials in electrocatalytic CO_(2)reduction are investigated and opportunities for their use are discussed.It is believed that this re-view will provide suggestions and guidance for developing defective carbon-based materials for CO_(2)reduction.
基金financially supported by the National Natural Science Foundation of China(Nos.51473081 and 51672143)Taishan Scholars Program,Outstanding Youth of Natural Science in Shandong Province(JQ201713)+1 种基金Natural Science Foundation of Shandong Province(ZR2017MEM018)ARC Discovery Project(No.170103317)
文摘Water splitting,as an advanced energy conversion technology,consists of two half reactions,including oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).However,the ideal electrocatalysts are noble metal based catalysts.Their high cost and scarcity in earth seriously restrict the large deployments.Ni Fe-based materials have attracted great attention in recent years due to their excellent catalytic properties for OER and HER.Nevertheless,their conductivity and electrochemical stability at high current density are unsatisfactory,resulting in ineffective water splitting due to high impedance and low stability.Recently,a series of catalysts coating Ni Fe-based materials on 3 D nickel foam were found to be extremely stable under the circumstance of high current density.In this review,we summarized the recent advances of NiFe-based materials on nickel foam for OER and HER,respectively,and further provided the perspectives for their future development.
文摘Background:The few previous studies that focused on the effects of compression garments(CG)on distance running performance have simultaneously measured electromyogram,physiological,and perceptual parameters.Therefore,this study investigated the effects of CG on muscle activation and median frequency during and after distance running,as well as blood-lactate concentration and rating of perceived exertion(RPE)during distance running.Methods:Eight healthy male recreational runners were recruited to randomly perform two 40 min treadmill running trials,one with CG,and the other with control garment made of normal cloth.The RPE and the surface electromyography(EMG)of 5 lower extremity muscles including gluteus maximus(GM),rectus femoris(RF),semitendinosus(ST),tibialis anterior(TA),and gastrocnemius(GAS)were measured during the running trial.The blood-lactate levels before and after the running trial were measured.Results:Wearing CG led to significant lower muscle activation(p<0.05)in the GM(decreased 7.40%-14.31%),RF(decreased 4.39%-4.76%),and ST(decreased 3.42%-7.20%)muscles;moreover,significant higher median frequency(p<0.05)in the GM(increased 5.57%)and ST(increased 10.58%)muscles.Wearing CG did not alter the RPE values or the blood-lactate levels(p>0.05).Conclusion:Wearing CG was associated with significantly lower muscle activation and higher median frequency in the running-related key muscles during distance running.This finding suggested that wearing CG may improve muscle function,which might enhance running performance and prevent muscle fatigue.
基金Funded by the National Natural Science Foundation of China(No.51603134)the Graduate Program Construction Project Funding of Sichuan University(No.2017KCSJ036)+1 种基金the Opening Project of Key Laboratory of Leather Chemistry and Engeering(Sichuan University)Ministry of Education(SCU2021D005)。
文摘Waterborne elastic polyester (WEP) with different content of hard polyester was applied in the maize starch (MS) based composites (MS/WEP) via solution casting method.The effects of WEP with different contents of hard polyester on the structure and properties of starch were studied by Fourier transform infrared,X-ray diffraction,ultraviolet-visible,tensile test,differential scanning calorimeter,thermogravimetric analysis and moisture measurement.The experimental results show that the addition of WEP does not change the crystalline type of starch,and only reduces the crystallinity of starch.And the structure and properties of MS/WEP are related to not only the content of starch but also the microstructure of WEP or the content of hard polyester in WEP.Waterborne elastic polyester with 30wt% hard polyester (WEP30) has the best modification effect on the maize starch among all the WEPs.For example,MS/WEP30 film has the optimum toughness,aging resistance and transmittance,the lowest crystallinity and glass transition temperature among all the MS/WEP films,and the lower moisture content.It is related to the compatibility between starch and WEP,resulting from the number of physical crosslinking points in WEP..
文摘A microscope method was developed for testing the blending ratio of akund/cotton blended yarns. Fiber characteristics such as diameter, longitudinal feature, and hollow structure were observed to identify akund and cotton. Therefore, the measurement of the blending ratio for akund/cotton blended yarns based on each fiber's amount, moisture regain, and metric count was available. The results show that using specimen's longitudinal section is more effective during the fiber counting than specimen's transverse section benefiting from the separation of the fibers.
文摘The effects of coagulation conditions on tensile properties of the regenerated cellulose fibers prepared by wet-spinning from NaOH/thiourea/urea(8∶6.5∶8 by weight)aqueous solvent were investigated by tensile tester,X-ray diffraction(XRD),and scanning electron microscope(SEM).The results show that the tensile properties of the as-spun fibers change with the coagualtion concentration,temperature,and time.When the spinning solution is coagulated in 10% H2SO4/12.5% Na2SO4 aqueous solution,the as-spun fibers have a typical structure of cellulose II,a circular cross-section,and homogeneous morphological structure.
文摘Cellulose pulps were directly dissolved in a green solvent of sodium hydrate/urea/thiourea/water with different composition for the purpose to prepare new regenerated cellulose fibers or films. The results showed that the highest solubility of cellulose in the solvent with the composition of 8/8/6.5/77.5. The results revealed that the pulp feeding sequence, stirring rate, pre-treatment of pulp and pulp size affected the cellulose concentration in the green solvent. Accordingly, the more effective dissolution method was proposed in order to get higher concentration of cellulose. Furthermore, the properties of solution prepared by different kinds of pulps in the solvent were investigated by ARES rheometer. Rheologieal analyses indicated that all cellulose aqueous solutions in their high concentration were pseudoplastic fluids and sensitive to temperature and tended to transform to gel when temperature increased.
基金Key Foundation of Shannxi Province,China (No.04JK181)China Textile Industry Association(No.2007049)
文摘A series of segmented polyether-polyester polyurethane with amorphous hydrophilic soft segment domains were prepared from 4,4'- diphenylmethane diisocyanate (MDI), polybutylene adipate (Glycol) 2000 (PBA2000), and polyethylene glycol 1000 (PEG1000), with 1,4-butanediol (BDO) as the chain extender. Furthermore, several representative properties of the polyurethanes, such as moisture permeability, water resistance, hydrophilic property, and phase inversion temperature, were investigated. The studies show that the structure and concentration of soft segment have a remarkable effect on the main application properties of polyurethane. On the contrary, the functional properties of the polyurethane are almost not affected by its hard segment.
基金New Century Excellent Talents of China ( NCET,No.040495)National Natural Science Foundation of China(NSFC, No.20474025)+1 种基金National Key Technology R&DProgram,China (No.2007BAE40B01)Innovative Research Team of Jiangnan University,China
文摘Without any preprocessing,polyester fabric has lower ability to hold on water and inks due to the smooth morphology of polyester fibers. Therefore, patterns directly printed with pigment inks have poor color yields and bleed easily. Pretreatments of polyester fabric were carried out with atmospheric air plasma under different experimental conditions. After plasma treatment the samples were printed with magenta pigment ink. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses indicated that the enhanced color performance was mainly contributed by not only the etching effect but also oxygen-containing polar groups induced onto fiber surfaces through plasma treatment. Thereby the surface modification of polyester fabrics using atmospheric-pressure air plasma offers a potential way to fabric pretreatment for pigment inkjet printing with the advantages of environmental friendly and energy saving over traditional pretreatment methods.
