Electrochemical corrosion of AZ31 magnesium alloy in the NH_(4)^(+)-SO_(4)2−-Cl−environment is studied.Effect of NH_(4)^(+)overshadows that of Cl−as the(NH_(4))_(2)SO_(4) concentration is 0.005 M or higher,yielding an...Electrochemical corrosion of AZ31 magnesium alloy in the NH_(4)^(+)-SO_(4)2−-Cl−environment is studied.Effect of NH_(4)^(+)overshadows that of Cl−as the(NH_(4))_(2)SO_(4) concentration is 0.005 M or higher,yielding an evolution from localized corrosion to uniform corrosion.Acceleration effect of NH_(4)^(+)can be attributed to that(i)NH_(4)^(+)dissolves the inner MgO and hinders the precipitation of Mg(OH)_(2) and(ii)the buffering ability of NH_(4)^(+)provides H+,enhances the hydrogen evolution,and expedites the corrosion process.The latter is demonstrated as the dominant factor with the results in unbuffered and buffered environments.The severe corrosion and hydrogen process in NH_(4)^(+)-containing solution results in a high Hads coverage and yields an inductive loop within the low frequency.Meanwhile,SO_(4)^(2−)is helpful in generating cracked but partially protective corrosion products,while Cl−could broaden the corrosion area beneath the corrosion product.展开更多
2D-layered graphitic carbon nitride(g-C_(3)N_(4))is regarded as a great prospect as a photocatalyst for H_(2)generation.However,g-C_(3)N_(4)’s photocatalytic hydrogen evolution(HER)activity is significantly restricte...2D-layered graphitic carbon nitride(g-C_(3)N_(4))is regarded as a great prospect as a photocatalyst for H_(2)generation.However,g-C_(3)N_(4)’s photocatalytic hydrogen evolution(HER)activity is significantly restricted by the recombination of photocarriers.We find that cobalt sulfide(CoS_(2))as a cocatalyst can promote g-C_(3)N_(4)nanosheets(NSs)to realize very efficient photocatalytic H_(2)generation.The prepared CoS_(2)/g-C_(3)N_(4)hybrids display highly boosted photocatalytic H_(2)generation performance and outstanding cycle stability.The optimized 7%-CoS_(2)/g-C_(3)N_(4)hybrids show a much improved photocatalytic H_(2)generation rate of 36.2μmol-1h-1,which is about 180 times as much as bare g-C_(3)N_(4)(0.2μmol-1h-1).In addition,the apparent quantum efficiency(AQE)of all the samples was computed under light atλ=370 nm,in which the AQE of 7%-CoS_(2)/g-C_(3)N_(4)hybrids is up to 5.72%.The experimental data and the DFT calculation suggest that the CoS_(2)/g-C_(3)N_(4)hybrid’s excellent HER activity is attributable to the lower overpotential and the smaller Co-H bond activation energy for HER.Accordingly,the CoS_(2)cocatalyst loading effectively boosts the photocatalytic performance of g-C_(3)N_(4)for H_(2)evolution.The project promotes fast development of high-efficiency photocatalysts and low-cost for photocatalytic H_(2)generation.展开更多
The biggest challenging issue in photocatalysis is efficient separation of the photoinduced carriers and the aggregation of photoexcited electrons on photocatalyst’s surface.In this paper,we report that double metall...The biggest challenging issue in photocatalysis is efficient separation of the photoinduced carriers and the aggregation of photoexcited electrons on photocatalyst’s surface.In this paper,we report that double metallic co-catalysts Ti3C2 MXene and metallic octahedral(1T)phase tungsten disulfide(WS2)act pathways transferring photoexcited electrons in assisting the photocatalytic H2 evolution.TiO2 nanosheets were in situ grown on highly conductive Ti3C2 MXenes and 1T-WS2 nanoparticles were then uniformly distributed on TiO2@Ti3C2 composite.Thus,a distinctive 1T-WS2@TiO2@Ti3C2 composite with double metallic co-catalysts was achieved,and the content of 1T phase reaches 73%.The photocatalytic H2 evolution performance of 1T-WS2@TiO2@Ti3C2 composite with an optimized 15 wt%WS2 ratio is nearly 50 times higher than that of TiO2 nanosheets because of conductive Ti3C2 MXene and 1T-WS2 resulting in the increase of electron transfer efficiency.Besides,the 1T-WS2 on the surface of TiO2@Ti3C2 composite enhances the Brunauer–Emmett–Teller surface area and boosts the density of active site.展开更多
Given the crucial role of land surface processes in global and regional climates, there is a pressing need to test and verify the performance of land surface models via comparisons to observations. In this study, the ...Given the crucial role of land surface processes in global and regional climates, there is a pressing need to test and verify the performance of land surface models via comparisons to observations. In this study, the eddy covariance measurements from 20 FLUXNET sites spanning more than 100 site-years were utilized to evaluate the performance of the Common Land Model (CoLM) over different vegetation types in various climate zones. A decomposition method was employed to separate both the observed and simulated energy fluxes, i.e., the sensible heat flux, latent heat flux, net radiation, and ground heat flux, at three timescales ranging from stepwise (30 rain) to monthly. A comparison between the simulations and observations indicated that CoLM produced satisfactory simulations of all four energy fluxes, although the different indexes did not exhibit consistent results among the different fluxes, A strong agreement between the simulations and observations was found for the seasonal cycles at the 20 sites, whereas CoLM underestimated the latent heat flux at the sites with distinct dry and wet seasons, which might be associated with its weakness in simulating soil water during the dry season. CoLM cannot explicitly simulate the midday depression of leaf gas exchange, which may explain why CoLM also has a maximum diurnal bias at noon in the summer. Of the eight selected vegetation types analyzed, CoLM performs best for evergreen broadleaf forests and worst for croplands and wetlands.展开更多
Herein, novel plasmonic Bi metal in situ deposited in reduced Ti O2 microspheres(Bi@R-Ti O2) are fabricated via a bimetallic MOF-derived synthesized strategy by adjusting the synthesizing temperature. Different charac...Herein, novel plasmonic Bi metal in situ deposited in reduced Ti O2 microspheres(Bi@R-Ti O2) are fabricated via a bimetallic MOF-derived synthesized strategy by adjusting the synthesizing temperature. Different characterization techniques, including XRD, SEM, TEM, XPS, DRS, PL, EIS, and photocurrent generation, are performed to investigate the structural and optical properties of the as-prepared samples. The results indicate that the Bi particles are generated inside and outside of reduced Ti O2 microspheres via the reduction of Ti4+ and Bi3+ by ethylene glycol. When the annealing temperature is controlled at 300 o C, the corresponding Bi@R-Ti O2-300 sample with an appropriate amount of Bi nanoparticles exhibits the highest full solar spectrum photocatalytic oxygen evolution activity(4728.709 μmol h–1 g–1), which is 5.9 and 9.5 times higher than that of pure Ti O2 and Bi-Ti bimetal organic frameworks(Bi-Ti-MOFs). Several reasons are suggested for the above results:(1) Bi metal behaves as an "electron acceptor" to accelerate the charge carrier transfer from Ti O2 to Bi;(2) The surface plasmon resonance effect of loaded metallic Bi particles can enhance the visible and NIR light absorption capacity;(3) The generation of Ti3+ further narrows the band gap of TiO2.展开更多
Triboelectric nanogenerators(TENG)have emerged as a highly promising energy harvesting technology,attracting significant attention in recent years for their broad applications.Gel-based TENGs,with superior stretchabil...Triboelectric nanogenerators(TENG)have emerged as a highly promising energy harvesting technology,attracting significant attention in recent years for their broad applications.Gel-based TENGs,with superior stretchability and sensitivity,have been widely reported as wearable sensors.However,the traditional hydrogel-based TENGs suffer from freezing at low temperatures and drying at high temperatures,resulting in malfunctions.In this study,we introduce an anti-freezing eutectogel,which uses a deep eutectic solvent(DES),to improve the stability and electrical conductivity of TENGs in harsh environmental conditions.The eutectogel-based TENG(E-TENG)produces an open-circuit voltage of 776 V,a short-circuit current of 1.54μA,and a maximum peak power of 1.1 mW.Moreover,the E-TENG exhibits exceptional mechanical properties with an elongation at a break of 476%under tension.Importantly,it maintains impressive performances across a wide temperature range from−18 to 60℃,with conductivities of 2.15 S/m at−10℃and 1.75 S/m at−18℃.Based on the excellent weight stability of the E-TENG sensor,motion sensing can be achieved in the air,and even underwater.Finally,the versatility of the E-TENG can serve as a wearable sensor,by integrating it with Bluetooth technology.The self-powered E-TENG can monitor various human motion signals in real-time and send the health signals directly to mobile phones.This research paves a new road for the applications of TENGs in harsh environments,offering wireless flexible sensors with real-time health signal monitoring capabilities.展开更多
With the growing economy and technology,disease prevention and individual health are becoming more and more important.It is highly urgent to develop a non-toxic,self-powered,and safe high-voltage power source to preve...With the growing economy and technology,disease prevention and individual health are becoming more and more important.It is highly urgent to develop a non-toxic,self-powered,and safe high-voltage power source to prevent diseases spread by mosquitoes,especially in isolated or remote areas.Herein,we reported a high-performance rotary triboelectric nanogenerator(R-TENG)based on customized theoretical simulations and a ferroelectric nanocomposite intermediate layer.The customized theoretical simulations based on gradient electrode gaps were established to optimize gap angles and segment numbers of the electrodes,which could prevent air breakdown and enhance the R-TENG output energy by at least 1.5 times.Meanwhile,the electrical output performance of the TENG was further enhanced with a highly oriented BaTiO3(BTO)nanoparticles intermediate layer by about 2.5 times.The open-circuit voltage of R-TENG reached more than 6 kV and could continuously light 3420 light-emitting devices(LEDs)or 4 serially connected 36 W household fluorescent lamps.Therefore,a self-powered high-voltage disease prevention system is developed based on the high-performance R-TENG to reduce the risk of disease transmission.This work provides a prospective strategy for the further development of TENGs and expands practical applications of self-powered and high-voltage systems.展开更多
To improve the corrosion resistance of key components and ensure the service safety of marine equipment,here we combined femtosecond(fs)laser fabrication and magnetron sputtering deposition to develop micro/nanostruct...To improve the corrosion resistance of key components and ensure the service safety of marine equipment,here we combined femtosecond(fs)laser fabrication and magnetron sputtering deposition to develop micro/nanostructured amorphous TiNbZr films.Analysis of the compositional,microstructural,corrosion,and mechanical properties was conducted.The results showed that the TiNbZr films were amorphous,and spherical TiNbZr nanoparticles uniformly covered the fs laser-induced periodic fringe structure.A complex hierarchical micro/nanostructure was formed that was hydrophobic and showed enhanced adhesion strength.The TiNbZr films deposited on fs laser-treated substrates provided the best corrosion resistance,showing a self-corrosion current density of 116 nA/cm^(2),excellent passive ability,and pitting resistance.The microscratch test revealed that the micro/nanostructures doubled the binding strength of the TiNbZr/316L interface due to the compositional and structural gradients induced by an approximately 20 nm transition layer formed during fs laser processing.This work provides a new method for obtaining anti-corrosion films with a high adhesion strength for marine applications.展开更多
In order to improve mechanical properties of refractory high entropy alloys,silicide was introduced and NbMoTiVSi_(x)(x=0,0.1,0.2,0.3,and 0.4,molar ratio) refractory high entropy alloys are prepared by vacuum arc melt...In order to improve mechanical properties of refractory high entropy alloys,silicide was introduced and NbMoTiVSi_(x)(x=0,0.1,0.2,0.3,and 0.4,molar ratio) refractory high entropy alloys are prepared by vacuum arc melting.Phase composition,micro structure evolution and mechanical properties were systematically studied.Results show that the silicide phase is formed in the alloys with addition of silicon,and the volume fraction of silicide increases from 0 to 8.3 % with increasing of silicon.Microstructure observation shows that the morphology of dendrite changes from columnar to near equiaxed,eutectic structure is formed at grain boundaries and composed of secondary BCC phase and silicide phase.The average length of the primary and second dendrites decreases with the increasing of silicon.Whereas,the ratio of eutectic structure increases from 0 to 19.8 % with the increment of silicon.The refinement of microstructure is caused by heterogeneous nucleation from the silicide.Compressive tests show that the yield and ultimate strength of the alloys increases from 1141.5 MPa to 2093.1 MPa and from 1700.1 MPa to 2374.7 MPa with increasing silicon content.The fracture strain decreases from 24.7 %-11.0 %.Fracture mechanism is changed from ductile fracture to ductile and brittle mixed fracture.The improvement of the strength is caused by grain bounda ry strengthening,which includes more boundaries around primary BCC phase and eutectic structure in grain boundary,both of them is resulted from the formation of silicide.展开更多
Contamination resulting from microbial adhesion on magnesium alloys is very common in many applications. Self-assembly technology was employed to prepare an antibacterial composite coating by fixing silver nanoparticl...Contamination resulting from microbial adhesion on magnesium alloys is very common in many applications. Self-assembly technology was employed to prepare an antibacterial composite coating by fixing silver nanoparticles (AgNPs) onto the surface of magnesium alloys. The AgNPs were immobilized on the surface of 3-aminopropyltrimethoxysilane (APTMS)-modified magnesium alloy AZ31 (APTMS/Mg) through electrosta- tic inter-attraction between partially protonated amino groups and negatively charged citrate-capped AgNPs, resulting in the AgNPs attached APTMS/Mg (AgNPs/APTMS/Mg) substrate. The prepared Ag colloid and functionalized AZ31 alloy were characterized by ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and electrochemical methods. Finally, the bactericidal activity of AgNPs/APTMS/Mg substrate against Escherichia coli was assessed by the inhibition zone. The results demonstrated that Si-O-Si covalent bonds existed on the substrate with the formation of inorganic Si-O-Mg bonds. AgNPs were immobilized and well-dispersed, forming a uniform submonolayer on the silane film in two dimensions. The AgNPs/APTMS-pretreated AZ31 alloys exhibited better corrosion resistance and excellent antibacterial performance.展开更多
The purpose of this work is to study the influences of Al and/or Ti addition on the microstructures, mechanical properties and corrosion properties of CoCrFeNi-(Al, Ti) high entropy alloy(HEA) coatings. Three coatings...The purpose of this work is to study the influences of Al and/or Ti addition on the microstructures, mechanical properties and corrosion properties of CoCrFeNi-(Al, Ti) high entropy alloy(HEA) coatings. Three coatings, AlCoCrFeNi(Ⅰ), CoCrFeNiTi_(0.5)(Ⅱ) and AlCoCrFeNiTi_(0.5)(Ⅲ), were fabricated by laser cladding successfully. The AlCoCrFeNi(Ⅰ) coating exhibited a simple body-centered cubic(BCC) solid-solution structure, whereas the CoCrFeNiTi_(0.5)(Ⅱ) alloy exhibited a face-centered cubic(FCC) solid-solution and a small amount of Laves phase. The BCC phases in AlCoCrFeNiTi _(0.5)(Ⅲ) coating were characterized as Fe–Cr rich disordered BCC phases(A2) and Al-Ni–Ti-rich ordered BCC phases(L2_1) separately. The AlCoCrFeNiTi_(0.5)(Ⅲ) coating with dual-phase BCC structure showed the optimal performance of both mechanical and corrosion properties, which was superior to BCC-based AlCoCrFeNi(Ⅰ) and FCC-based CoCrFeNiTi_(0.5)(Ⅱ) coatings. Nanoindentation tests and quantitative investigations on the strengthening mechanisms of AlCoCrFeNiTi_(0.5)(Ⅲ) coating were conducted, suggesting that the precipitation strengthening is the dominant strengthening mechanism. In short, the addition of moderate amount of Al and Ti in CoCrFeNi HEA shows potential for the development of a high strength and corrosion-resistant coating.展开更多
The porous few-layer g-C_(3)N_(4)(PFL-g-C_(3)N_(4))is prepared by a simple molecular self-assembly method.Compared with pure g-C_(3)N_(4),the as-prepared PFL-g-C_(3)N_(4) is ultrathin,the surface is rich in pores,and ...The porous few-layer g-C_(3)N_(4)(PFL-g-C_(3)N_(4))is prepared by a simple molecular self-assembly method.Compared with pure g-C_(3)N_(4),the as-prepared PFL-g-C_(3)N_(4) is ultrathin,the surface is rich in pores,and the photocatalytic nitrogen fixation activity is greatly increased to 8.20 mM h^(-1) gCat^(-1).Few-layer and ultrathin nature of PFL-g-C_(3)N_(4) can provide a larger specific surface area,expose more active sites,and reduce the diffusion path of charges and protons from the inside to the surface.In addition,the porous structure can narrow the band gap,thereby increasing the light absorption range and enhancing the light absorption capability.Meanwhile,the presence of nitrogen vacancies causes PFL-g-C_(3)N_(4) to move to a more negative conductive band value.More importantly,the isotopic experiments using ^(15)N_(2) as nitrogen source confirm the ammonia production originating from N2 rather than the decomposition of g-C_(3)N_(4).Therefore,PFL-g-C_(3)N_(4) can greatly improve the efficiency of visible light photocatalytic nitrogen fixation.展开更多
The superhydrophobic surface was fabricated on the AZ31 alloy by the combination of the hydrotherreal treatment method and post modification with stearic acid. The superhydrophobic surface showed a static water contac...The superhydrophobic surface was fabricated on the AZ31 alloy by the combination of the hydrotherreal treatment method and post modification with stearic acid. The superhydrophobic surface showed a static water contact angle of 157.6°. The characteristics of the coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The corrosion resistance of the superhydrophobic coatings was investigated by potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS). The results revealed that the superhydrophobic coatings, characterized by petal-like structure significantly improved the corrosion resistance of the AZ31 ahoy.展开更多
To improve the strength and ductility of Ti Al alloys by second phase, Ti46 Al4 Nb1 Mo alloys doped with different B content(0.4%, 0.8%, 1.2%, 1.6% and 2.0%, atomic percent, hereafter in at.%, referred to as TNMx B) w...To improve the strength and ductility of Ti Al alloys by second phase, Ti46 Al4 Nb1 Mo alloys doped with different B content(0.4%, 0.8%, 1.2%, 1.6% and 2.0%, atomic percent, hereafter in at.%, referred to as TNMx B) were prepared. Macro/microstructure evolution, mechanical properties and deformation mechanisms of the alloys were studied systematically. Results showed that the microstructure of TNM-0.4 B and TNM-0.8 B alloy remained columnar dendrites, and the secondary dendritic arms of columnar grains were more obvious. When the content of B is 1.2%, the columnar dendrites transformed to equiaxed grains, and theα2/γ lamellae colony size was further refined in TNM-1.6 B and TNM-2.0 B alloy. The morphologies and kinds of the borides were changed with increasing B content, XRD results showed that Ti B phase appeared with 1.6%B content, and both Ti B and Ti B2 phase formed in TNM-2.0 B alloy. There were straight and curved Ti B phases located around grain boundaries in TNM-0.4 B and TNM-0.8 B alloy, and when the content of B increased to 1.2%, the curved Ti B phases were reduced, while the tiny and straight Ti B phases increased. With further increasing B content to 1.6% and 2.0%, the tiny and straight Ti B phases were coarser. Compressive testing results showed that the mechanical properties of the TNM alloy were enhanced with increasing B content. The maximum strength and strain of TNM alloy were 2339 MPa and33.7% with 1.6% B addition. The compressive strength and strain were mainly enhanced via refinement of lamellar colony and formation of Ti B, and it is found that pile-up of dislocations and deformed twins promoted by Ti B are predominant in improving the mechanical properties of TNM alloys with higher strength and strain.展开更多
Recently,widespread attention has been devoted to the typical layered BiOCl or BiOBr because of the suitable nanostructure and band structure.However,owing to the fast carrier recombination,the photocatalytic performa...Recently,widespread attention has been devoted to the typical layered BiOCl or BiOBr because of the suitable nanostructure and band structure.However,owing to the fast carrier recombination,the photocatalytic performance of BiOX materials is not so satisfactory.Loading 1T phase WS_(2)nanosheets(NSs)onto Bi_(5)O_(7)Br NSs can improve the photocatalytic N_(2)fixation activity.Among these,the obtained 1T-WS_(2)@Bi_(5)O_(7)Br composites with optimum 5%1T-WS_(2)NSs display a significantly improved photocatalytic N_(2)fixation rate(8.43 mmol L^(−1)h^(−1)g^(−1)),2.51 times higher than pure Bi_(5)O_(7)Br(3.36 mmol L^(−1)h^(−1)g^(−1)).And the outstanding stability of 1T-WS_(2)@Bi_(5)O_(7)Br-5 composites is also achieved.Exactly,the photoexcited electrons from Bi_(5)O_(7)Br NSs are quickly transferred to conductive 1T phase WS_(2)as electron acceptors,which can promote the separation of carriers.In addition,1T-WS_(2)NSs can provide abundant active sites on the basal and edge planes,which can promote the efficiency of photocatalytic N_(2)fixation.This work offers a novel solution to improve the photocatalytic performance of Bi_(5)O_(7)Br NSs.展开更多
Highly ordered Ag2 S/ZnS/ZnO nanorod array film photoanodes were prepared on a Ti substrate for photocathodic cathodic protection.The results indicated that the photoresponse range of the Ag2S/ZnS/ZnO composite film w...Highly ordered Ag2 S/ZnS/ZnO nanorod array film photoanodes were prepared on a Ti substrate for photocathodic cathodic protection.The results indicated that the photoresponse range of the Ag2S/ZnS/ZnO composite film was extended compared to those of the ZnO and ZnS/ZnO films,indicating its higher light absorption capacity.When the Ag2S/ZnS/ZnO composite film served as a photoanode,the film can provide the best effective photocathodic protection for 304 stainless steel in a 3.5 wt%NaCl solution under white light illumination compared to the ZnO and ZnS/ZnO films.Additionally,in comparison to pure ZnO film,the photocurrent for the ZnS/ZnO film remained the same without noticeable fluctuation after illumination for 1 h,indicating that the ZnS functionalization improved the stability by overcoming the photocorrosion effect of the ZnO photoanode under light irradiation.展开更多
Energy piles are a new type of heat exchange systems with buried pipes in a pile foundation,which optimize a ground source heat pump system for the utilization of shallow geothermal energy.In this study,based on the p...Energy piles are a new type of heat exchange systems with buried pipes in a pile foundation,which optimize a ground source heat pump system for the utilization of shallow geothermal energy.In this study,based on the principle of similarity,the thermo-mechanical behavior of the model energy pile with a large cross-section in saturated sandy soil was experimentally evaluated.The pre-cast model concrete pile with a diameter of 0.2 m and length of 1.5 m was buried in saturated sand in a steel box with dimensions of 2.5 m×2.5 m×2.0 m(length×width×height).The pile was heated using water in the polyethylene(PE)pipe,which was connected to a water cycle temperature controller.At a constant inlet water temperature of 55℃,three thermal cycles were carried out with the same heating and cooling periods and different water flow rates.The temperature distributions in the pile and soil,in addition to the pore pressure,soil pressure,and displacement of the pile,were monitored to clarify the thermo-mechanical behavior of the pile and soil.The heat transfer efficiency was analyzed based on the temperature difference and water flow rates.The measured strain at different locations in the pile under cyclic thermal loading revealed that the uneven strain that developed in a pile body should be considered for its long-term application.Furthermore,focus should be directed toward the long-term unrecoverable displacement of the energy pile due to the thermal plastic strain and thermal consolidation of the soil.展开更多
It was found that the supplement of 10<sup>-4</sup> mol/L AgNO<sub>3</sub> in N6 medium enhanced the induction of type Ⅰembryogenic calli from immature embryos of maize inbred P9-10. After hig...It was found that the supplement of 10<sup>-4</sup> mol/L AgNO<sub>3</sub> in N6 medium enhanced the induction of type Ⅰembryogenic calli from immature embryos of maize inbred P9-10. After high-osmotic treatment, the induced calli was taken as transformation recipient to be bombarded with plasmid pMG6 carrying synthetic Bt gene by PDS-1000/He genegun. A total of 14 resistant calli were obtained after screening subsequently on the mediums with gradually increasing selective pressure. 10 plants were regenerated from the resistant calli on 3 different induction media,and 8 out of the 10 regenerated plants were confirmed to be integrated with Bt gene by PCR and Southern blotting analysis. Results of ELISA showed that the Bt-protein content in the leaves of the transgenic plants varied between 20—200 ng/g fresh weight.展开更多
In the present work,the structure,magnetic properties,and cryogenic magnetocaloric effect of weberite-type oxides Gd_(3)MO_(7)(M=Nb,Sb,and Ta)are reported through powder X-ray diffraction,bulk susceptibility,and heat ...In the present work,the structure,magnetic properties,and cryogenic magnetocaloric effect of weberite-type oxides Gd_(3)MO_(7)(M=Nb,Sb,and Ta)are reported through powder X-ray diffraction,bulk susceptibility,and heat capacity measurements,as well as scaling law analysis and a mean-field approach.A remarkably large isothermal magnetic entropy change of 354.0 m J K^(-1)cm^(-3)is observed for Gd_(3)SbO_(7)under an external field of 9 T at 2.0 K.The relative cooling power is estimated to be 618.9 J kg^(-1)(4.8 J cm^(-3))for an applied field of 8.9 T,with the largest adiabatic temperature change being 22.4 K at 6.3 K.The magnetocaloric performance of these oxides is quite impressive when compared with the benchmark magnetic refrigerant,gadolinium gallium garnet(Gd_(3)Ga_(5)O_(12),GGG).Therefore,Gd_(3)MO_(7)(M=Nb,Sb,and Ta)are promising alternatives for cryogenic cooling techniques,especially for the magnetic liquefaction of helium.展开更多
Defect existing form and its evolution play an important role in the thermoelectric transport process. Here different forms of Pb into the Sn Se system were introduced in order to improve the thermoelectric and mechan...Defect existing form and its evolution play an important role in the thermoelectric transport process. Here different forms of Pb into the Sn Se system were introduced in order to improve the thermoelectric and mechanical properties of Sn Se. Pb/Sn Se samples were fabricated by vacuum melting, solid phase diffusion,spark plasma sintering and annealing treatment. The element valence mapping diagram and the X-ray photoelectron spectra(XPS) characteristic peaks of Pb show that a certain amount of elemental Pb exists in the initial state, and evolves into Pb^(2+)ion after annealing treatment. The micro-structure evolution leads to significant enhancement of the power factor and the ZT value. The power factor(PF) and the ZT value for Pb/Sn Se increases to 623 μW/m/K^(2) and 1.12 at 773 K after annealing treatment, respectively.Compared with Sn Se matrix, the hardness and fracture toughness of Pb/Sn Se samples increased by about40% and 10%, respectively. Reasonable control of microstructure evolution is expected to be a design idea to improve thermoelectric and mechanical properties of Sn Se.展开更多
基金support of National Natural Science Foundation of China(No.U2106216)the National Science and Technology Resources Investigation Program of China(No.2019FY101400)the Youth Innovation Plan of Shandong Province(2019KJD001).
文摘Electrochemical corrosion of AZ31 magnesium alloy in the NH_(4)^(+)-SO_(4)2−-Cl−environment is studied.Effect of NH_(4)^(+)overshadows that of Cl−as the(NH_(4))_(2)SO_(4) concentration is 0.005 M or higher,yielding an evolution from localized corrosion to uniform corrosion.Acceleration effect of NH_(4)^(+)can be attributed to that(i)NH_(4)^(+)dissolves the inner MgO and hinders the precipitation of Mg(OH)_(2) and(ii)the buffering ability of NH_(4)^(+)provides H+,enhances the hydrogen evolution,and expedites the corrosion process.The latter is demonstrated as the dominant factor with the results in unbuffered and buffered environments.The severe corrosion and hydrogen process in NH_(4)^(+)-containing solution results in a high Hads coverage and yields an inductive loop within the low frequency.Meanwhile,SO_(4)^(2−)is helpful in generating cracked but partially protective corrosion products,while Cl−could broaden the corrosion area beneath the corrosion product.
基金funding from the National Natural Science Foundation of China(No.51872173 and 51772176)Taishan Scholar Foundation of Shandong Province(No.tsqn201812068 and tspd20161006)+2 种基金Youth Innovation Technology Project of Higher School in Shandong Province(No.2019KJA013)Science and Technology Special Project of Qingdao City(No.20-3-4-3-nsh)the Opening Fund of State Key Laboratory of Heavy Oil Processing(No.SKLOP202002006)。
文摘2D-layered graphitic carbon nitride(g-C_(3)N_(4))is regarded as a great prospect as a photocatalyst for H_(2)generation.However,g-C_(3)N_(4)’s photocatalytic hydrogen evolution(HER)activity is significantly restricted by the recombination of photocarriers.We find that cobalt sulfide(CoS_(2))as a cocatalyst can promote g-C_(3)N_(4)nanosheets(NSs)to realize very efficient photocatalytic H_(2)generation.The prepared CoS_(2)/g-C_(3)N_(4)hybrids display highly boosted photocatalytic H_(2)generation performance and outstanding cycle stability.The optimized 7%-CoS_(2)/g-C_(3)N_(4)hybrids show a much improved photocatalytic H_(2)generation rate of 36.2μmol-1h-1,which is about 180 times as much as bare g-C_(3)N_(4)(0.2μmol-1h-1).In addition,the apparent quantum efficiency(AQE)of all the samples was computed under light atλ=370 nm,in which the AQE of 7%-CoS_(2)/g-C_(3)N_(4)hybrids is up to 5.72%.The experimental data and the DFT calculation suggest that the CoS_(2)/g-C_(3)N_(4)hybrid’s excellent HER activity is attributable to the lower overpotential and the smaller Co-H bond activation energy for HER.Accordingly,the CoS_(2)cocatalyst loading effectively boosts the photocatalytic performance of g-C_(3)N_(4)for H_(2)evolution.The project promotes fast development of high-efficiency photocatalysts and low-cost for photocatalytic H_(2)generation.
基金fundings from the National Natural Science Foundation of China (Nos. 51872173 and 51772167)Taishan Scholarship of Young Scholars (No. tsqn201812068)+2 种基金Natural Science Foundation of Shandong Province (No. ZR2017JL020)Taishan Scholarship of Climbing Plan (No. tspd20161006)Key Research and Development Program of Shandong Province (No. 2018GGX102028)
文摘The biggest challenging issue in photocatalysis is efficient separation of the photoinduced carriers and the aggregation of photoexcited electrons on photocatalyst’s surface.In this paper,we report that double metallic co-catalysts Ti3C2 MXene and metallic octahedral(1T)phase tungsten disulfide(WS2)act pathways transferring photoexcited electrons in assisting the photocatalytic H2 evolution.TiO2 nanosheets were in situ grown on highly conductive Ti3C2 MXenes and 1T-WS2 nanoparticles were then uniformly distributed on TiO2@Ti3C2 composite.Thus,a distinctive 1T-WS2@TiO2@Ti3C2 composite with double metallic co-catalysts was achieved,and the content of 1T phase reaches 73%.The photocatalytic H2 evolution performance of 1T-WS2@TiO2@Ti3C2 composite with an optimized 15 wt%WS2 ratio is nearly 50 times higher than that of TiO2 nanosheets because of conductive Ti3C2 MXene and 1T-WS2 resulting in the increase of electron transfer efficiency.Besides,the 1T-WS2 on the surface of TiO2@Ti3C2 composite enhances the Brunauer–Emmett–Teller surface area and boosts the density of active site.
基金supported by the R&D Special Fund for Nonprofit Industry (Meteorology) (Grant Nos. GYHY200706025, GYHY201206013 and GYHY201306066)
文摘Given the crucial role of land surface processes in global and regional climates, there is a pressing need to test and verify the performance of land surface models via comparisons to observations. In this study, the eddy covariance measurements from 20 FLUXNET sites spanning more than 100 site-years were utilized to evaluate the performance of the Common Land Model (CoLM) over different vegetation types in various climate zones. A decomposition method was employed to separate both the observed and simulated energy fluxes, i.e., the sensible heat flux, latent heat flux, net radiation, and ground heat flux, at three timescales ranging from stepwise (30 rain) to monthly. A comparison between the simulations and observations indicated that CoLM produced satisfactory simulations of all four energy fluxes, although the different indexes did not exhibit consistent results among the different fluxes, A strong agreement between the simulations and observations was found for the seasonal cycles at the 20 sites, whereas CoLM underestimated the latent heat flux at the sites with distinct dry and wet seasons, which might be associated with its weakness in simulating soil water during the dry season. CoLM cannot explicitly simulate the midday depression of leaf gas exchange, which may explain why CoLM also has a maximum diurnal bias at noon in the summer. Of the eight selected vegetation types analyzed, CoLM performs best for evergreen broadleaf forests and worst for croplands and wetlands.
基金the National Natural Science Foundation of China(51872173 and 51772176)Taishan Scholarship of Young Scholars(tsqn201812068)+2 种基金Natural Science Foundation of Shandong Province(ZR2017JL020)Taishan Scholarship of Climbing Plan(tspd20161006)Key Research and Development Program of Shandong Province(2018GGX102028)~~
文摘Herein, novel plasmonic Bi metal in situ deposited in reduced Ti O2 microspheres(Bi@R-Ti O2) are fabricated via a bimetallic MOF-derived synthesized strategy by adjusting the synthesizing temperature. Different characterization techniques, including XRD, SEM, TEM, XPS, DRS, PL, EIS, and photocurrent generation, are performed to investigate the structural and optical properties of the as-prepared samples. The results indicate that the Bi particles are generated inside and outside of reduced Ti O2 microspheres via the reduction of Ti4+ and Bi3+ by ethylene glycol. When the annealing temperature is controlled at 300 o C, the corresponding Bi@R-Ti O2-300 sample with an appropriate amount of Bi nanoparticles exhibits the highest full solar spectrum photocatalytic oxygen evolution activity(4728.709 μmol h–1 g–1), which is 5.9 and 9.5 times higher than that of pure Ti O2 and Bi-Ti bimetal organic frameworks(Bi-Ti-MOFs). Several reasons are suggested for the above results:(1) Bi metal behaves as an "electron acceptor" to accelerate the charge carrier transfer from Ti O2 to Bi;(2) The surface plasmon resonance effect of loaded metallic Bi particles can enhance the visible and NIR light absorption capacity;(3) The generation of Ti3+ further narrows the band gap of TiO2.
基金the Natural Science Foundation of Shandong Province,China(No.ZR2021QE043)the National Natural Science Foundation of China(Nos.52101390 and 52331004)the Open Project of Key Lab of Special Functional Materials of Ministry of Education,Henan University(No.KFKT-2022-11).
文摘Triboelectric nanogenerators(TENG)have emerged as a highly promising energy harvesting technology,attracting significant attention in recent years for their broad applications.Gel-based TENGs,with superior stretchability and sensitivity,have been widely reported as wearable sensors.However,the traditional hydrogel-based TENGs suffer from freezing at low temperatures and drying at high temperatures,resulting in malfunctions.In this study,we introduce an anti-freezing eutectogel,which uses a deep eutectic solvent(DES),to improve the stability and electrical conductivity of TENGs in harsh environmental conditions.The eutectogel-based TENG(E-TENG)produces an open-circuit voltage of 776 V,a short-circuit current of 1.54μA,and a maximum peak power of 1.1 mW.Moreover,the E-TENG exhibits exceptional mechanical properties with an elongation at a break of 476%under tension.Importantly,it maintains impressive performances across a wide temperature range from−18 to 60℃,with conductivities of 2.15 S/m at−10℃and 1.75 S/m at−18℃.Based on the excellent weight stability of the E-TENG sensor,motion sensing can be achieved in the air,and even underwater.Finally,the versatility of the E-TENG can serve as a wearable sensor,by integrating it with Bluetooth technology.The self-powered E-TENG can monitor various human motion signals in real-time and send the health signals directly to mobile phones.This research paves a new road for the applications of TENGs in harsh environments,offering wireless flexible sensors with real-time health signal monitoring capabilities.
基金The research is supported by the National Natural Science Foundation of China(Nos.52101390,52125205,U20A20166,61805015,and 61804011)Natural Science Foundation of Shandong Province,China(No.ZR2021QE043)+3 种基金Fundamental Research Funds for the Central Universities,China(No.202112011)Open Project of Key Lab of Special Functional Materials of Ministry of Education,Henan University(No.KFKT-2022-11)Natural Science Foundation of Beijing Municipality(No.Z180011)Joint Funds of National Natural Science Foundation of China(No.U2106216).
文摘With the growing economy and technology,disease prevention and individual health are becoming more and more important.It is highly urgent to develop a non-toxic,self-powered,and safe high-voltage power source to prevent diseases spread by mosquitoes,especially in isolated or remote areas.Herein,we reported a high-performance rotary triboelectric nanogenerator(R-TENG)based on customized theoretical simulations and a ferroelectric nanocomposite intermediate layer.The customized theoretical simulations based on gradient electrode gaps were established to optimize gap angles and segment numbers of the electrodes,which could prevent air breakdown and enhance the R-TENG output energy by at least 1.5 times.Meanwhile,the electrical output performance of the TENG was further enhanced with a highly oriented BaTiO3(BTO)nanoparticles intermediate layer by about 2.5 times.The open-circuit voltage of R-TENG reached more than 6 kV and could continuously light 3420 light-emitting devices(LEDs)or 4 serially connected 36 W household fluorescent lamps.Therefore,a self-powered high-voltage disease prevention system is developed based on the high-performance R-TENG to reduce the risk of disease transmission.This work provides a prospective strategy for the further development of TENGs and expands practical applications of self-powered and high-voltage systems.
基金financially supported by the National Natural Science Foundation of China(Nos.51971121 and 52002228)the National Natural Science Foundation of China-Shandong Joint Fund for Marine Science Research Centers(CN)(No.U2106216).
文摘To improve the corrosion resistance of key components and ensure the service safety of marine equipment,here we combined femtosecond(fs)laser fabrication and magnetron sputtering deposition to develop micro/nanostructured amorphous TiNbZr films.Analysis of the compositional,microstructural,corrosion,and mechanical properties was conducted.The results showed that the TiNbZr films were amorphous,and spherical TiNbZr nanoparticles uniformly covered the fs laser-induced periodic fringe structure.A complex hierarchical micro/nanostructure was formed that was hydrophobic and showed enhanced adhesion strength.The TiNbZr films deposited on fs laser-treated substrates provided the best corrosion resistance,showing a self-corrosion current density of 116 nA/cm^(2),excellent passive ability,and pitting resistance.The microscratch test revealed that the micro/nanostructures doubled the binding strength of the TiNbZr/316L interface due to the compositional and structural gradients induced by an approximately 20 nm transition layer formed during fs laser processing.This work provides a new method for obtaining anti-corrosion films with a high adhesion strength for marine applications.
基金supported by National Natural Science Foundation of China(Grant No.51825401,51971121)Fundamental Research Funds of Henan University of Technology(Grant No.2018QNJH25)+1 种基金Scientific Research Fund of State Key Laboratory of Materials Processing and Die&Mould Technology(Grant No.P2020-023)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(NO:2016ZT06G025)。
文摘In order to improve mechanical properties of refractory high entropy alloys,silicide was introduced and NbMoTiVSi_(x)(x=0,0.1,0.2,0.3,and 0.4,molar ratio) refractory high entropy alloys are prepared by vacuum arc melting.Phase composition,micro structure evolution and mechanical properties were systematically studied.Results show that the silicide phase is formed in the alloys with addition of silicon,and the volume fraction of silicide increases from 0 to 8.3 % with increasing of silicon.Microstructure observation shows that the morphology of dendrite changes from columnar to near equiaxed,eutectic structure is formed at grain boundaries and composed of secondary BCC phase and silicide phase.The average length of the primary and second dendrites decreases with the increasing of silicon.Whereas,the ratio of eutectic structure increases from 0 to 19.8 % with the increment of silicon.The refinement of microstructure is caused by heterogeneous nucleation from the silicide.Compressive tests show that the yield and ultimate strength of the alloys increases from 1141.5 MPa to 2093.1 MPa and from 1700.1 MPa to 2374.7 MPa with increasing silicon content.The fracture strain decreases from 24.7 %-11.0 %.Fracture mechanism is changed from ductile fracture to ductile and brittle mixed fracture.The improvement of the strength is caused by grain bounda ry strengthening,which includes more boundaries around primary BCC phase and eutectic structure in grain boundary,both of them is resulted from the formation of silicide.
基金supported by National Natural Science Foundation of China(No.51241001)NSF of Shandong Province(No.ZR2011EMM004)+2 种基金open foundation of State Key Laboratory for Corrosion and Protection(NoSKLCP21012KF03)Taishan Scholarship Project of Shandong Province(No.TS20110828)Basic Research Project of Qingdao Science and Technology Program(No.13-1-4-171-jch)
文摘Contamination resulting from microbial adhesion on magnesium alloys is very common in many applications. Self-assembly technology was employed to prepare an antibacterial composite coating by fixing silver nanoparticles (AgNPs) onto the surface of magnesium alloys. The AgNPs were immobilized on the surface of 3-aminopropyltrimethoxysilane (APTMS)-modified magnesium alloy AZ31 (APTMS/Mg) through electrosta- tic inter-attraction between partially protonated amino groups and negatively charged citrate-capped AgNPs, resulting in the AgNPs attached APTMS/Mg (AgNPs/APTMS/Mg) substrate. The prepared Ag colloid and functionalized AZ31 alloy were characterized by ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and electrochemical methods. Finally, the bactericidal activity of AgNPs/APTMS/Mg substrate against Escherichia coli was assessed by the inhibition zone. The results demonstrated that Si-O-Si covalent bonds existed on the substrate with the formation of inorganic Si-O-Mg bonds. AgNPs were immobilized and well-dispersed, forming a uniform submonolayer on the silane film in two dimensions. The AgNPs/APTMS-pretreated AZ31 alloys exhibited better corrosion resistance and excellent antibacterial performance.
基金financially supported by the Taishan Scholarship of Climbing Plan(No.tspd20161006)the National Natural Science Foundation of China(Nos.51772176 and 51971121)。
文摘The purpose of this work is to study the influences of Al and/or Ti addition on the microstructures, mechanical properties and corrosion properties of CoCrFeNi-(Al, Ti) high entropy alloy(HEA) coatings. Three coatings, AlCoCrFeNi(Ⅰ), CoCrFeNiTi_(0.5)(Ⅱ) and AlCoCrFeNiTi_(0.5)(Ⅲ), were fabricated by laser cladding successfully. The AlCoCrFeNi(Ⅰ) coating exhibited a simple body-centered cubic(BCC) solid-solution structure, whereas the CoCrFeNiTi_(0.5)(Ⅱ) alloy exhibited a face-centered cubic(FCC) solid-solution and a small amount of Laves phase. The BCC phases in AlCoCrFeNiTi _(0.5)(Ⅲ) coating were characterized as Fe–Cr rich disordered BCC phases(A2) and Al-Ni–Ti-rich ordered BCC phases(L2_1) separately. The AlCoCrFeNiTi_(0.5)(Ⅲ) coating with dual-phase BCC structure showed the optimal performance of both mechanical and corrosion properties, which was superior to BCC-based AlCoCrFeNi(Ⅰ) and FCC-based CoCrFeNiTi_(0.5)(Ⅱ) coatings. Nanoindentation tests and quantitative investigations on the strengthening mechanisms of AlCoCrFeNiTi_(0.5)(Ⅲ) coating were conducted, suggesting that the precipitation strengthening is the dominant strengthening mechanism. In short, the addition of moderate amount of Al and Ti in CoCrFeNi HEA shows potential for the development of a high strength and corrosion-resistant coating.
基金fundings from the National Natural Science Foundation of China(No.51872173 and 51772167)Taishan Scholarship of Young Scholars(No.tsqn201812068)+3 种基金Taishan Scholarship of Climbing Plan(No.tspd20161006)Key Research and Development Program of Shandong Province(No.2018GGX102028)Natural Science Foundation of Shandong Province(No.ZR2017JL020)Higher School Youth Innovation Team of Shandong Province(No.2019KJA013).
文摘The porous few-layer g-C_(3)N_(4)(PFL-g-C_(3)N_(4))is prepared by a simple molecular self-assembly method.Compared with pure g-C_(3)N_(4),the as-prepared PFL-g-C_(3)N_(4) is ultrathin,the surface is rich in pores,and the photocatalytic nitrogen fixation activity is greatly increased to 8.20 mM h^(-1) gCat^(-1).Few-layer and ultrathin nature of PFL-g-C_(3)N_(4) can provide a larger specific surface area,expose more active sites,and reduce the diffusion path of charges and protons from the inside to the surface.In addition,the porous structure can narrow the band gap,thereby increasing the light absorption range and enhancing the light absorption capability.Meanwhile,the presence of nitrogen vacancies causes PFL-g-C_(3)N_(4) to move to a more negative conductive band value.More importantly,the isotopic experiments using ^(15)N_(2) as nitrogen source confirm the ammonia production originating from N2 rather than the decomposition of g-C_(3)N_(4).Therefore,PFL-g-C_(3)N_(4) can greatly improve the efficiency of visible light photocatalytic nitrogen fixation.
基金supported by the National Natural Science Foundation of China(No.21306214)the Applied Basic Research Foundation of Qingdao(No.13-1-4-217-jch)+2 种基金the Scientific Research Foundation of Shandong for Outstanding Young Scientists(No.BS2013CL009)the Doctoral Program Foundation of the State Education Ministry(No.20133718120003)the SDUST Research Fund(No.2014TDJH104)
文摘The superhydrophobic surface was fabricated on the AZ31 alloy by the combination of the hydrotherreal treatment method and post modification with stearic acid. The superhydrophobic surface showed a static water contact angle of 157.6°. The characteristics of the coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The corrosion resistance of the superhydrophobic coatings was investigated by potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS). The results revealed that the superhydrophobic coatings, characterized by petal-like structure significantly improved the corrosion resistance of the AZ31 ahoy.
基金supported by the National Natural Science Foundation of China (No. 51825401, 51971121)the China Postdoctoral Science Foundation (2019TQ0077, 2019M660071)。
文摘To improve the strength and ductility of Ti Al alloys by second phase, Ti46 Al4 Nb1 Mo alloys doped with different B content(0.4%, 0.8%, 1.2%, 1.6% and 2.0%, atomic percent, hereafter in at.%, referred to as TNMx B) were prepared. Macro/microstructure evolution, mechanical properties and deformation mechanisms of the alloys were studied systematically. Results showed that the microstructure of TNM-0.4 B and TNM-0.8 B alloy remained columnar dendrites, and the secondary dendritic arms of columnar grains were more obvious. When the content of B is 1.2%, the columnar dendrites transformed to equiaxed grains, and theα2/γ lamellae colony size was further refined in TNM-1.6 B and TNM-2.0 B alloy. The morphologies and kinds of the borides were changed with increasing B content, XRD results showed that Ti B phase appeared with 1.6%B content, and both Ti B and Ti B2 phase formed in TNM-2.0 B alloy. There were straight and curved Ti B phases located around grain boundaries in TNM-0.4 B and TNM-0.8 B alloy, and when the content of B increased to 1.2%, the curved Ti B phases were reduced, while the tiny and straight Ti B phases increased. With further increasing B content to 1.6% and 2.0%, the tiny and straight Ti B phases were coarser. Compressive testing results showed that the mechanical properties of the TNM alloy were enhanced with increasing B content. The maximum strength and strain of TNM alloy were 2339 MPa and33.7% with 1.6% B addition. The compressive strength and strain were mainly enhanced via refinement of lamellar colony and formation of Ti B, and it is found that pile-up of dislocations and deformed twins promoted by Ti B are predominant in improving the mechanical properties of TNM alloys with higher strength and strain.
基金funding from the National Natural Science Foundation of China(Nos.51872173 and 51772176)Taishan Scholars Program of Shandong Province(No.tsqn201812068)+1 种基金Higher School Youth Innovation Team of Shandong Province(No.2019KJA013)Science and Technology Special Project of Qingdao City(No.20-3-4-3-nsh).
文摘Recently,widespread attention has been devoted to the typical layered BiOCl or BiOBr because of the suitable nanostructure and band structure.However,owing to the fast carrier recombination,the photocatalytic performance of BiOX materials is not so satisfactory.Loading 1T phase WS_(2)nanosheets(NSs)onto Bi_(5)O_(7)Br NSs can improve the photocatalytic N_(2)fixation activity.Among these,the obtained 1T-WS_(2)@Bi_(5)O_(7)Br composites with optimum 5%1T-WS_(2)NSs display a significantly improved photocatalytic N_(2)fixation rate(8.43 mmol L^(−1)h^(−1)g^(−1)),2.51 times higher than pure Bi_(5)O_(7)Br(3.36 mmol L^(−1)h^(−1)g^(−1)).And the outstanding stability of 1T-WS_(2)@Bi_(5)O_(7)Br-5 composites is also achieved.Exactly,the photoexcited electrons from Bi_(5)O_(7)Br NSs are quickly transferred to conductive 1T phase WS_(2)as electron acceptors,which can promote the separation of carriers.In addition,1T-WS_(2)NSs can provide abundant active sites on the basal and edge planes,which can promote the efficiency of photocatalytic N_(2)fixation.This work offers a novel solution to improve the photocatalytic performance of Bi_(5)O_(7)Br NSs.
基金This work was supported financially by the Funding from the Taishan Scholarship of Climbing Plan(No.tspd20161006)the National Natural Science Foundation of China(No.51772176)the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents(No.2017RCJJ018).
文摘Highly ordered Ag2 S/ZnS/ZnO nanorod array film photoanodes were prepared on a Ti substrate for photocathodic cathodic protection.The results indicated that the photoresponse range of the Ag2S/ZnS/ZnO composite film was extended compared to those of the ZnO and ZnS/ZnO films,indicating its higher light absorption capacity.When the Ag2S/ZnS/ZnO composite film served as a photoanode,the film can provide the best effective photocathodic protection for 304 stainless steel in a 3.5 wt%NaCl solution under white light illumination compared to the ZnO and ZnS/ZnO films.Additionally,in comparison to pure ZnO film,the photocurrent for the ZnS/ZnO film remained the same without noticeable fluctuation after illumination for 1 h,indicating that the ZnS functionalization improved the stability by overcoming the photocorrosion effect of the ZnO photoanode under light irradiation.
基金This work was supported by the national Natural Science Foundation of China[Grant No(s).5137215551678369]the Technical Innovation Foundation of Shenzhen[Grant No.JCYJ20170302143610976].
文摘Energy piles are a new type of heat exchange systems with buried pipes in a pile foundation,which optimize a ground source heat pump system for the utilization of shallow geothermal energy.In this study,based on the principle of similarity,the thermo-mechanical behavior of the model energy pile with a large cross-section in saturated sandy soil was experimentally evaluated.The pre-cast model concrete pile with a diameter of 0.2 m and length of 1.5 m was buried in saturated sand in a steel box with dimensions of 2.5 m×2.5 m×2.0 m(length×width×height).The pile was heated using water in the polyethylene(PE)pipe,which was connected to a water cycle temperature controller.At a constant inlet water temperature of 55℃,three thermal cycles were carried out with the same heating and cooling periods and different water flow rates.The temperature distributions in the pile and soil,in addition to the pore pressure,soil pressure,and displacement of the pile,were monitored to clarify the thermo-mechanical behavior of the pile and soil.The heat transfer efficiency was analyzed based on the temperature difference and water flow rates.The measured strain at different locations in the pile under cyclic thermal loading revealed that the uneven strain that developed in a pile body should be considered for its long-term application.Furthermore,focus should be directed toward the long-term unrecoverable displacement of the energy pile due to the thermal plastic strain and thermal consolidation of the soil.
文摘It was found that the supplement of 10<sup>-4</sup> mol/L AgNO<sub>3</sub> in N6 medium enhanced the induction of type Ⅰembryogenic calli from immature embryos of maize inbred P9-10. After high-osmotic treatment, the induced calli was taken as transformation recipient to be bombarded with plasmid pMG6 carrying synthetic Bt gene by PDS-1000/He genegun. A total of 14 resistant calli were obtained after screening subsequently on the mediums with gradually increasing selective pressure. 10 plants were regenerated from the resistant calli on 3 different induction media,and 8 out of the 10 regenerated plants were confirmed to be integrated with Bt gene by PCR and Southern blotting analysis. Results of ELISA showed that the Bt-protein content in the leaves of the transgenic plants varied between 20—200 ng/g fresh weight.
基金supported by the Science,Technology and Innovation Commission of Shenzhen Municipality(Grant Nos.JCYJ20190808152217447,JCYJ20180305125212075,JCYJ20180507182246321,and JCYJ20210324095611032)the National Natural Science Foundation of China(Grant Nos.51925804,11904236,11934017,and 11921004)+3 种基金the Beijing Natural Science Foundation(Grant No.Z200007)the National Key R&D Program of China(Grant Nos.2018YFE0103200,and 2018YFA0305700)the Chinese Academy of Sciences(Grant No.XDB33000000)the support from the Young Innovative Talents Project for Regular Universities in Guangdong Province(Grant No.2018KQNCX396)。
文摘In the present work,the structure,magnetic properties,and cryogenic magnetocaloric effect of weberite-type oxides Gd_(3)MO_(7)(M=Nb,Sb,and Ta)are reported through powder X-ray diffraction,bulk susceptibility,and heat capacity measurements,as well as scaling law analysis and a mean-field approach.A remarkably large isothermal magnetic entropy change of 354.0 m J K^(-1)cm^(-3)is observed for Gd_(3)SbO_(7)under an external field of 9 T at 2.0 K.The relative cooling power is estimated to be 618.9 J kg^(-1)(4.8 J cm^(-3))for an applied field of 8.9 T,with the largest adiabatic temperature change being 22.4 K at 6.3 K.The magnetocaloric performance of these oxides is quite impressive when compared with the benchmark magnetic refrigerant,gadolinium gallium garnet(Gd_(3)Ga_(5)O_(12),GGG).Therefore,Gd_(3)MO_(7)(M=Nb,Sb,and Ta)are promising alternatives for cryogenic cooling techniques,especially for the magnetic liquefaction of helium.
基金financially supported by the National Natural Science Foundation of China (No. 51772176)the Science and Technology Development Project of Shandong Province (No.2019JZZY010303)the Shandong Natural Science(No. ZR2015EM013)。
文摘Defect existing form and its evolution play an important role in the thermoelectric transport process. Here different forms of Pb into the Sn Se system were introduced in order to improve the thermoelectric and mechanical properties of Sn Se. Pb/Sn Se samples were fabricated by vacuum melting, solid phase diffusion,spark plasma sintering and annealing treatment. The element valence mapping diagram and the X-ray photoelectron spectra(XPS) characteristic peaks of Pb show that a certain amount of elemental Pb exists in the initial state, and evolves into Pb^(2+)ion after annealing treatment. The micro-structure evolution leads to significant enhancement of the power factor and the ZT value. The power factor(PF) and the ZT value for Pb/Sn Se increases to 623 μW/m/K^(2) and 1.12 at 773 K after annealing treatment, respectively.Compared with Sn Se matrix, the hardness and fracture toughness of Pb/Sn Se samples increased by about40% and 10%, respectively. Reasonable control of microstructure evolution is expected to be a design idea to improve thermoelectric and mechanical properties of Sn Se.