The combined effects of straw incorporation(SI)and polymer-coated urea(PCU)application on soil ammonia(NH_(3))and nitrous oxide(N_(2)O)emissions from agricultural fields have not been comprehensively evaluated in Nort...The combined effects of straw incorporation(SI)and polymer-coated urea(PCU)application on soil ammonia(NH_(3))and nitrous oxide(N_(2)O)emissions from agricultural fields have not been comprehensively evaluated in Northwest China.We conducted a two-year field experiment to assess the effects of combining SI with either uncoated urea(U)or PCU on soil NH_(3)emissions,N_(2)O emissions,winter wheat yields,yield-scaled NH_(3)(/NH_(3)),and yield-scaled N_(2)O(/N_(2)O).Five treatments were investigated,no nitrogen(N)fertilizer(N_(0)),U application at 150 kg N ha-1 with and without SI(SI+U and S_(0)+U),and PCU application at 150 kg N ha^(-1) with and without SI(SI+PCU and S_(0)+PCU).The results showed that the NH_(3);emissions increased by 20.98-34.35%following Sl compared to straw removal,mainly due to increases in soil ammonium(NH_(4)^(+)-N)content and water-flled pore space(WFPS).SI resulted in higher N_(2)O emissions than under the So scenario by 13.31-49.23%due to increases in soil inorganic N(SIN)contents,WFPS,and soil microbial biomass.In contrast,the PCU application reduced the SIN contents compared to the U application,reducing the NH_(3)and N_(2)O emissions by 45.99-58.07 and 18.08-53.04%,respectively.Moreover,no significant positive effects of the SI or PCU applications on the winter wheat yield were observed.The lowest /NH_(3) and /N_(2)O values were observed under the S_(0)+PCU and SI+PCU treatments.Our results suggest that single PCU applications and their combination with straw are the optimal agricultural strategies for mitigating gaseous N emissions and maintaining optimal winter wheat yields in Northwest China.展开更多
Using cetyl-trimethyl-ammonium bromide (CTMAB) as template and tetraethylortho-silicate (TEOS) as silica source, the MCM-41 mesoporous materials incorporated in framework by Y, Nd and Sm were synthesized by hydrot...Using cetyl-trimethyl-ammonium bromide (CTMAB) as template and tetraethylortho-silicate (TEOS) as silica source, the MCM-41 mesoporous materials incorporated in framework by Y, Nd and Sm were synthesized by hydrothermal synthesis method. The structure, morphology of materials and the state of Y, Nd, Sm in materials were investigated by means of XRD, nitrogen adsorption-desorption, SEM, IR spectrometry, TG-DTA. The XRD results indicate that the samples possess the mesoporous MCM-41 structures with ordered hexagonal arrangements. Y, Nd and Sm ions can get into the framework of mesoporous materials. Nitrogen adsorption desorption isotherms show that the samples have typical mesopores characteristics. SEM micrographs reveal that incorporated sampies show a spherical morphology and the diameters are averagely 0. l0 to 0.15 μm. In IR spectrum of samples, there are the feature adsorption peaks about Si-O-Ln(Ln=Y, Sm, Nd)at 960-985 cm^-1, which affirm that Y, Nd, Sm ions locate in the framework of several mesoporous materials. Results from TG-DTA analysis suggest that two different template sorption sites exist in the framework of YMCM-41, SmMCM-41, NdMCM-41, which powerfully proves that the presence of Y, Nd and Sm in Si framework of the materials.展开更多
Exploration of cost-effective electrocatalysts for boosting the overall water-splitting efficiency is vitally important for obtaining renewable fuels such as hydrogen.Here,earth-abundant CoxNi1-xO nanowire arrays were...Exploration of cost-effective electrocatalysts for boosting the overall water-splitting efficiency is vitally important for obtaining renewable fuels such as hydrogen.Here,earth-abundant CoxNi1-xO nanowire arrays were used as a structural framework to dilute Ir incorporation for fabricating electrocatalysts for water splitting.Minimal Ir-incorporated CoxNi1-xO nanowire arrays were synthesized through the facile hydrothermal method with subsequent calcination by using Ni foam(NF)as both the substrate and source of Ni.The electrocatalytic water-splitting performance was found to crucially depend on the Ir content of the parent CoxNi1-xO nanowire arrays.As a result,for a minimal Ir content,as low as 0.57 wt%,the obtained Ir-CoxNi1-xO/NF electrodes exhibited optimal catalytic activity in terms of a low overpotential of 260 mV for the oxygen evolution reaction and 53 mV for the hydrogen evolution reaction at 10 mA cm?2 in 1 mol L–1 KOH.When used as bifunctional electrodes in water splitting,the current density of 10 mA cm–2 was obtained at a low cell voltage of 1.55 V.Density functional theory calculations revealed that the Ir-doped CoxNi1-xO arrays exhibited enhanced electrical conductivity and low Gibbs free energy,which contributed to the improved electrocatalytic activity.The present study presents a new strategy for the development of transition metal oxide electrocatalysts with low levels of Ir incorporation for efficient water splitting.展开更多
Graphitic carbon nitride(g-C3N4)-based photocatalysts have shown great potential in the splitting of water.However,the intrinsic drawbacks of g-C3N4,such as low surface area,poor diffusion,and charge separation effici...Graphitic carbon nitride(g-C3N4)-based photocatalysts have shown great potential in the splitting of water.However,the intrinsic drawbacks of g-C3N4,such as low surface area,poor diffusion,and charge separation efficiency,remain as the bottleneck to achieve highly efficient hydrogen evolution.Here,a hollow oxygen-incorporated g-C3N4 nanosheet(OCN)with an improved surface area of 148.5 m2 g^−1 is fabricated by the multiple thermal treatments under the N2/O2 atmosphere,wherein the C–O bonds are formed through two ways of physical adsorption and doping.The physical characterization and theoretical calculation indicate that the O-adsorption can promote the generation of defects,leading to the formation of hollow morphology,while the O-doping results in reduced band gap of g-C3N4.The optimized OCN shows an excellent photocatalytic hydrogen evolution activity of 3519.6μmol g^−1 h^−1 for~20 h,which is over four times higher than that of g-C3N4(850.1μmol g^−1 h^−1)and outperforms most of the reported g-C3N4 catalysts.展开更多
Low carbon Al2O3- C refractory materials were prepared by "Al/Si metal incorporated, insitu formed non-oxides" method using corundum, Al powder, Si powder and flake graphite as starting materials. High temperature s...Low carbon Al2O3- C refractory materials were prepared by "Al/Si metal incorporated, insitu formed non-oxides" method using corundum, Al powder, Si powder and flake graphite as starting materials. High temperature strength, stress -strain relationship and thermal shock resistance of these composites were investigated. The results show that these composites possess improved high temperature strength and good thermal shock resistance. When A1 addition increases from 0 to 8 mass%, correspondingly, Si addition decreases from 8 mass% to O, hot modulus of rupture at 1 400 ℃ increases significantly from 10. 4 MPa to 32. 4 MPa; the maximum strain under 6.5 MPa stress at 1400 ℃ decreases from 215 t.tm to 90 μm; residual strength ratio after 3 thermal shock cycles (1 100 ℃ , air quenching) decreases from 80% to 65%. This may be attributed to in-situ formation of nonoxides because Al and Si react with C, CO and N, to form Al4C3 , AlN and SiC creating strengthening and toughening effects.展开更多
In the present investigation, we fabricated strontium (Sr2+) incorporated CsPbI2Br-based inorganic perovskite solar cells in ambient conditions. The morphology, crystallinity, absorption, elemental composition and pho...In the present investigation, we fabricated strontium (Sr2+) incorporated CsPbI2Br-based inorganic perovskite solar cells in ambient conditions. The morphology, crystallinity, absorption, elemental composition and photoluminescence analysis of the bare CsPbI2Br and CsPb1-xSrxI2Br perovskite thin films were studied systematically to investigate the role of Sr2+ incorporation. It is observed that the surface morphology of the CsPbI2Br perovskite thin film has been improved by partial substitution of Pb2+ by Sr2+ which facilitates photoactive black phase-stabilization and defect passivation. The champion device having CsPb0.98Sr0.02I2Br composition exhibited a power conversion efficiency (PCE) of 16.61% which is much higher than the bare device (13.65%). Furthermore, our CsPb0.98Sr0.02I2Br-based devices maintain > 85% of its initial efficiency over 100 h in ambient conditions.展开更多
All-inorganic CsPbI_(2)Br perovskite solar cells(PSCs)have received extensive research interests recently.Nevertheless,their low efficiency and poor long-term stability are still obstacles for further commercial appli...All-inorganic CsPbI_(2)Br perovskite solar cells(PSCs)have received extensive research interests recently.Nevertheless,their low efficiency and poor long-term stability are still obstacles for further commercial application.Herein,we demonstrate that high efficiency and exceptional long-term stability are realized by incorporating gadolinium(III)chloride(GdCl_(3))into the CsPbI_(2)Br perovskite film.The incorporation of GdCl_(3) enhances the Goldschmidt tolerance factor of CsPbI_(2)Br perovskite,yielding a dense perovskite film with small grains,thus the a-phase CsPbI_(2)Br is remarkably stabilized.Additionally,it is found that the GdCl_(3)-incorporated perovskite film achieves suppressed charge recombination and appropriate energy level alignment compared with the pristine CsPbI_(2)Br film.The noticeable increment in efficiency from14.01%(control PSC)to 16.24%is achieved for GdCl_(3)-incorporated PSC.Moreover,the nonencapsulated GdCl_(3)-incorporated PSC exhibits excellent environmental and thermal stability,remaining over 91%or90%of the original efficiency after 1200 h aging at 40%relative humidity or 480 h heating at 85℃ in nitrogen glove box respectively.The encapsulated GdCl_(3)-incorporated PSC presents an improved operational stability with over 88%of initial efficiency under maximum power point(MPP)tracking at 45℃ for1000 h.This work presents an effective ion-incorporation approach for boosting efficiency and long-term stability of all-inorganic PSCs.展开更多
A convenient synthetic method with high yields for aryl-incorporated ditosylates by reaction of aryl-incorporated diols with TsCI in THF/NaOH/H2O solution was described. Some of these aryl-incorporated ditosylates rea...A convenient synthetic method with high yields for aryl-incorporated ditosylates by reaction of aryl-incorporated diols with TsCI in THF/NaOH/H2O solution was described. Some of these aryl-incorporated ditosylates reacted with diphenols to produce crown ethers in pleasant yield.展开更多
This article reports a preliminary research on silicate-incorporated hydroxyapatite as a new environmental mineral used to remove cadmium ions from aqueous solutions. The silicate-incorporated hydroxyapatite was prepa...This article reports a preliminary research on silicate-incorporated hydroxyapatite as a new environmental mineral used to remove cadmium ions from aqueous solutions. The silicate-incorporated hydroxyapatite was prepared by coprecipitation and calcining, and silicate was incorporated into the crystal lattice of hydroxyapatite by partial substitution of phosphate. The amount of cadmium ions removed by silicate-incorporated hydroxyapatite was significantly elevated, which was 76% higher than that of pure hydroxyapatite. But the sorption behavior of cadmium ions on silicate-incorporated hydroxyapatite was similar to that of pure hydroxyapatite. Morphological study revealed that silicate incorporation confined the crystal growth and increased the specific surface area of hydroxyapatite, which were in favor of enhancing the cadmium ion sorption capacity of the samples. Incorporation of silicate into hydroxyapatite seems to be an effective approach to improve the environmental property of hydroxyapatite on removal of aqueous cadmium ions.展开更多
Carbonaceous nanomaterials such as carbon nanotubes (CNTs), magnetic metal nanomaterials and semicon- ductor nanomaterials are superior candidates for microwave absorbers. Taking full advantage of the features of CN...Carbonaceous nanomaterials such as carbon nanotubes (CNTs), magnetic metal nanomaterials and semicon- ductor nanomaterials are superior candidates for microwave absorbers. Taking full advantage of the features of CNTs, nanophase cobalt and nanophase zinc oxide, whose main microwave absorption mechanisms are based on resistance loss, magnetic loss and dielectric loss, we fabricate CNT/Co and CNT/ZnO heterostructure nanocom- posites, respectively. By using the CNTs, CNT/Co nanocomposites and CNT/ZnO nanocomposites as nanofillers, composites with polyester as matrix are prepared by in situ polymerization, and their microwave absorption per- formance is studied. It is indicated that the synergetic effects of the physic properties of different components in nano-heterostructures result in greatly enhanced microwave absorption performance in a wide frequency range. The absorption peak is increased, the absorption bandwidth is broadened, and the maximum peak shifts to a lower frequency.展开更多
Using cetyl-trimethyl-ammonium bromide (CTMAB) as template agent and tetraethylorthosilicate (TEOS) as silica Source, the MCM-41 mesoporous materials were synthesized with Y, Nd and Sm incorporated in the framewor...Using cetyl-trimethyl-ammonium bromide (CTMAB) as template agent and tetraethylorthosilicate (TEOS) as silica Source, the MCM-41 mesoporous materials were synthesized with Y, Nd and Sm incorporated in the framework under hydrothermal conditions. The structure and the micro-morphology of the materials and the state of Y, Nd and Sm were investigated through the analyses of XRD, nitrogen adsorption-desorption isotherm, SEM, IR and TG-DTA. The XRD resuits indicate that the synthetic samples are of typical structure of mesoporous MCM-41 with ordered hexagonal arrangements, and Y, Nd and Sm can be incorporated into the framework of these mesoporous materials. Nitrogen adsorption-desorption isotherms show that the samples possess the typical mesopores character. SEM micrographs reveal that the incorporated samples show a well-defined spherical morphology with the diameter ranging 0.10 - 0.15μm. The occurrence of two different template sorption sites in the framework as revealed by TG-DTA analysis further suggests the presence of Y, Nd and Sm in siliceous framework.展开更多
0 Introduction From a sociolinguistic perspective,competence in language use is determined not only by the ability to use language with grammatical accuracy,but also to use language appropriate to particular contexts....0 Introduction From a sociolinguistic perspective,competence in language use is determined not only by the ability to use language with grammatical accuracy,but also to use language appropriate to particular contexts.Thus,successful language learning requires language users to know the culture that underlies language.However,in foreign language teaching practice,culture teaching is often neglected,or introduced as no more than a supplementary diversion to language instruction.And the methods on how to teach the cultural knowledge is attached even less importance to.展开更多
Four field trials were conducted over a three-year period (2011-2013) at various locations in Ontario to evaluate the level of weed control provided by halosulfuron applied PPI,PREor POST at 17.5, 35 and 70 g&midd...Four field trials were conducted over a three-year period (2011-2013) at various locations in Ontario to evaluate the level of weed control provided by halosulfuron applied PPI,PREor POST at 17.5, 35 and 70 g·ai·ha-1 in white bean. Halosulfuron applied PPI or PRE at 17.5, 35 and 35 g·ai·ha-1 caused 2% or less visible injury 1 and 4 WAA in white bean. However, halosulfuron applied POST at 17.5, 35 and 70 g·ai·ha-1 caused 2% - 8% and 1% - 3% white bean injury at 1 and 4 WAA, respectively. There was no decrease in white bean seed yield relative to the weed free check due to weed interference with halosulfuron applied PPI or PRE at doses evaluated, except when applied PRE at 17.5 g·ai·ha-1 which resulted in a decrease in seed yield of 25%. Weed interference caused a decrease in white bean yield of 47%, 42% and 44%, when halosulfuron was applied POST at 17.5, 35 and 70 g·ai·ha-1, respectively. Halosulfuron applied PPI, PRE and POST controlled AMARE 92% - 100%, 85% - 99% and 47% - 75%;CHEAL 95% - 100%, 83% - 99% and 36% - 51%;and SINAR 97% - 100%, 99% - 100% and 100%, respectively. Halosulfuron applied PPI and PRE reduced AMARE density 93% - 97% and 75% - 95%;CHEAL density 89% - 98% and 81% - 93%;and SINAR density 99% - 100% and 99% - 100%, respectively. Halosulfuron applied PPI and PRE reduced dry weight of AMARE 96% - 98% and 86% - 96%;CHEAL 96% - 98% and 87% - 93%;and SINAR 100% and 100%, respectively. Halosulfuron applied POST at rates evaluated reduced SINAR density and dry weight 100% but caused no significant reduction in AMARE and CHEAL density or dry weight compared to the weedy check. Based on these results, halosulfuron applied PPI orPREat 35 g·ai·ha-1 can be used safely for the control of selected broadleaf weeds in white bean production.展开更多
The Zeolite Y as a support was modified by the incorporating of Fe and TiO2 in one single step using impregnation method. The synergistic effects between those components enhance the catalytic activity for the degrada...The Zeolite Y as a support was modified by the incorporating of Fe and TiO2 in one single step using impregnation method. The synergistic effects between those components enhance the catalytic activity for the degradation of amaranth dye under ultrasonic irradiation with output power of 50 W and 40 kHz frequency. Different characterization techniques were used to elucidate the physical and chemical properties of the produced catalysts. The XRD results indicated that the type of titanium precursor significantly effects on the crystallinity of 0.4% Fe/15%TiO2-NaY catalyst. The AFM results detected that the TiO2 formed a layer covered the surface of zeolite while Fe clusters were located close to TiO2. The influence of reaction parameters such as TiO2 and Fe content, pH values, amount of hydrogen peroxide used, catalyst loading and the initial dye concentration were investigated for the decolorization efficiency of amaranth. The maximum decolorization efficiency for 0.4%Fe/15%TiO2-NaY was 100% after 120 min of reaction time with an initial dye concentration of 30 mg/L, 2 g/L of catalyst loading, natural pH about 5.5 and 0.65 mM H2O2.展开更多
Cobalt-rich perovskite oxides play a paramount role in catalyzing oxygen evolution reaction(OER)on account of their acceptable intrinsic activity but are still challenging due to the high costs and undesired stability...Cobalt-rich perovskite oxides play a paramount role in catalyzing oxygen evolution reaction(OER)on account of their acceptable intrinsic activity but are still challenging due to the high costs and undesired stability.In response to the defects,herein,the Mg-incorporated perovskite cobaltite SrCo_(0.6)Fe_(0.3M)g_(0.1)O_(3-δ)(SCFM-0.1)is proposed as a novel earth-abundant and durable OER electrocatalyst.A well-consolidated cubic-symmetry structure and more active oxygen intermediates are enabled upon Mg substitution.Hence,the optimized SCFM-0.1 perovskite oxide achieves prominent OER electrocatalytic performance,that is,a low overpotential of only 320 mV at 10 mA cm^(-2),a small Tafel slope of 65 mV dec^(-1),as well as an outstanding durability within 20 h,substantially outperforming that of the pristine SrCo_(0.7)Fe_(0.3)O_(3-δ)and benchmark Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ)and IrO_(2) catalysts.The strong pHdependent behavior associated with lattice oxygen activation mechanism for SCFM-0.1 catalyst is also confirmed.This work paves a unique avenue to develop cost-effective and robust perovskite cobaltites for efficient OER electrocatalysis.展开更多
The immobilization of SiW_(12)O_(40)^(4-)in poly(4-aminoazobenzene)film was done by electrochemical method.According to the continuous cyclic voltammograms of the modified electrode,it can be determined that SiW_(12)O...The immobilization of SiW_(12)O_(40)^(4-)in poly(4-aminoazobenzene)film was done by electrochemical method.According to the continuous cyclic voltammograms of the modified electrode,it can be determined that SiW_(12)O_(40)^(4-) in the polymer is very stable.The paper reports the elecctrochemical pro- perties of the modified electrode,Moreover,it was found that the modified electrode exhibits electrocatalysis for the reaction of oxygen.展开更多
Several gelatin-silicate composites, with or without incorporation of Ca2+ ions, were synthesized through sol-gel processing starting from gelatin and 3- (glycidoxypropyl) trimethoxysilane. The structure around the Si...Several gelatin-silicate composites, with or without incorporation of Ca2+ ions, were synthesized through sol-gel processing starting from gelatin and 3- (glycidoxypropyl) trimethoxysilane. The structure around the Si atoms was similar for all the samples. The measurement of viscoelastic properties indicated that the glass transition temperature and activation energy decreased with the incorporation of Ca2+ ions. The Ca2+ ion-containing composites were bioactive as they spontaneously deposited apatite when soaked in a simulated body fluid of the Kokubo recipe.展开更多
Recent price movement Most benchmark prices decreased over the past month. Chinese prices moved sharply lower.Open interest has shifted from July and into the December contract. After moving lower in early May, values...Recent price movement Most benchmark prices decreased over the past month. Chinese prices moved sharply lower.Open interest has shifted from July and into the December contract. After moving lower in early May, values for the July contract were volatile but rangebound between 65 and 70 cents/lb for most of the past month. Values for the December contract also moved lower in early May. While they had been rangebound, December prices have been testing the lower end of their recent range, briefly dropping below 65 cents/lb in the latest trading.展开更多
Recent price movement Benchmark prices were flat or slightly higherover the pastmonth. Prices for the May NY futures contract increased over past month,climbing from levels just below 70 cents/lb in mid-February to th...Recent price movement Benchmark prices were flat or slightly higherover the pastmonth. Prices for the May NY futures contract increased over past month,climbing from levels just below 70 cents/lb in mid-February to those near 74 cents/lb recently.展开更多
基金This work was supported by the National Key R&D Program of China(2021YFD1900700)the National Natural Science Foundation of China(52179046).
文摘The combined effects of straw incorporation(SI)and polymer-coated urea(PCU)application on soil ammonia(NH_(3))and nitrous oxide(N_(2)O)emissions from agricultural fields have not been comprehensively evaluated in Northwest China.We conducted a two-year field experiment to assess the effects of combining SI with either uncoated urea(U)or PCU on soil NH_(3)emissions,N_(2)O emissions,winter wheat yields,yield-scaled NH_(3)(/NH_(3)),and yield-scaled N_(2)O(/N_(2)O).Five treatments were investigated,no nitrogen(N)fertilizer(N_(0)),U application at 150 kg N ha-1 with and without SI(SI+U and S_(0)+U),and PCU application at 150 kg N ha^(-1) with and without SI(SI+PCU and S_(0)+PCU).The results showed that the NH_(3);emissions increased by 20.98-34.35%following Sl compared to straw removal,mainly due to increases in soil ammonium(NH_(4)^(+)-N)content and water-flled pore space(WFPS).SI resulted in higher N_(2)O emissions than under the So scenario by 13.31-49.23%due to increases in soil inorganic N(SIN)contents,WFPS,and soil microbial biomass.In contrast,the PCU application reduced the SIN contents compared to the U application,reducing the NH_(3)and N_(2)O emissions by 45.99-58.07 and 18.08-53.04%,respectively.Moreover,no significant positive effects of the SI or PCU applications on the winter wheat yield were observed.The lowest /NH_(3) and /N_(2)O values were observed under the S_(0)+PCU and SI+PCU treatments.Our results suggest that single PCU applications and their combination with straw are the optimal agricultural strategies for mitigating gaseous N emissions and maintaining optimal winter wheat yields in Northwest China.
文摘Using cetyl-trimethyl-ammonium bromide (CTMAB) as template and tetraethylortho-silicate (TEOS) as silica source, the MCM-41 mesoporous materials incorporated in framework by Y, Nd and Sm were synthesized by hydrothermal synthesis method. The structure, morphology of materials and the state of Y, Nd, Sm in materials were investigated by means of XRD, nitrogen adsorption-desorption, SEM, IR spectrometry, TG-DTA. The XRD results indicate that the samples possess the mesoporous MCM-41 structures with ordered hexagonal arrangements. Y, Nd and Sm ions can get into the framework of mesoporous materials. Nitrogen adsorption desorption isotherms show that the samples have typical mesopores characteristics. SEM micrographs reveal that incorporated sampies show a spherical morphology and the diameters are averagely 0. l0 to 0.15 μm. In IR spectrum of samples, there are the feature adsorption peaks about Si-O-Ln(Ln=Y, Sm, Nd)at 960-985 cm^-1, which affirm that Y, Nd, Sm ions locate in the framework of several mesoporous materials. Results from TG-DTA analysis suggest that two different template sorption sites exist in the framework of YMCM-41, SmMCM-41, NdMCM-41, which powerfully proves that the presence of Y, Nd and Sm in Si framework of the materials.
基金financially supported by the National Natural Science Foundation of China (51772255)the Hunan Provincial Innovation Foundation For Postgraduate (CX2017B274)+1 种基金the National Basic Research Program of China (2015CB921103)the Program for Changjiang Scholars and Innovative Research Team in University (IRT13093)~~
文摘Exploration of cost-effective electrocatalysts for boosting the overall water-splitting efficiency is vitally important for obtaining renewable fuels such as hydrogen.Here,earth-abundant CoxNi1-xO nanowire arrays were used as a structural framework to dilute Ir incorporation for fabricating electrocatalysts for water splitting.Minimal Ir-incorporated CoxNi1-xO nanowire arrays were synthesized through the facile hydrothermal method with subsequent calcination by using Ni foam(NF)as both the substrate and source of Ni.The electrocatalytic water-splitting performance was found to crucially depend on the Ir content of the parent CoxNi1-xO nanowire arrays.As a result,for a minimal Ir content,as low as 0.57 wt%,the obtained Ir-CoxNi1-xO/NF electrodes exhibited optimal catalytic activity in terms of a low overpotential of 260 mV for the oxygen evolution reaction and 53 mV for the hydrogen evolution reaction at 10 mA cm?2 in 1 mol L–1 KOH.When used as bifunctional electrodes in water splitting,the current density of 10 mA cm–2 was obtained at a low cell voltage of 1.55 V.Density functional theory calculations revealed that the Ir-doped CoxNi1-xO arrays exhibited enhanced electrical conductivity and low Gibbs free energy,which contributed to the improved electrocatalytic activity.The present study presents a new strategy for the development of transition metal oxide electrocatalysts with low levels of Ir incorporation for efficient water splitting.
基金This work was supported by the National Science Foundation of China(51772152,51702129,51572114,51972150,21908110,and 51902161)Fundamental Research Funds for the Central Universities(30919011269,30919011110,and 1191030558)+3 种基金Y.W.thanks the Key University Science Research Project of Jiangsu province(16KJB430009)Y.Z.thanks for the support from the Postdoctoral Science Foundation(2018M630527)China Scholarship Council(201708320150)J.S.thanks the Natural Science Foundation of Jiangsu Province(BK20190479,1192261031693).
文摘Graphitic carbon nitride(g-C3N4)-based photocatalysts have shown great potential in the splitting of water.However,the intrinsic drawbacks of g-C3N4,such as low surface area,poor diffusion,and charge separation efficiency,remain as the bottleneck to achieve highly efficient hydrogen evolution.Here,a hollow oxygen-incorporated g-C3N4 nanosheet(OCN)with an improved surface area of 148.5 m2 g^−1 is fabricated by the multiple thermal treatments under the N2/O2 atmosphere,wherein the C–O bonds are formed through two ways of physical adsorption and doping.The physical characterization and theoretical calculation indicate that the O-adsorption can promote the generation of defects,leading to the formation of hollow morphology,while the O-doping results in reduced band gap of g-C3N4.The optimized OCN shows an excellent photocatalytic hydrogen evolution activity of 3519.6μmol g^−1 h^−1 for~20 h,which is over four times higher than that of g-C3N4(850.1μmol g^−1 h^−1)and outperforms most of the reported g-C3N4 catalysts.
基金supported by Henan Scientific and Technological Research Projects(112102210095)the Education Department of Henan Province Natural Science Foundation(2011A430024)Science Fund for Distinguished Young Scholars of Henan Province (No.124100510019)
文摘Low carbon Al2O3- C refractory materials were prepared by "Al/Si metal incorporated, insitu formed non-oxides" method using corundum, Al powder, Si powder and flake graphite as starting materials. High temperature strength, stress -strain relationship and thermal shock resistance of these composites were investigated. The results show that these composites possess improved high temperature strength and good thermal shock resistance. When A1 addition increases from 0 to 8 mass%, correspondingly, Si addition decreases from 8 mass% to O, hot modulus of rupture at 1 400 ℃ increases significantly from 10. 4 MPa to 32. 4 MPa; the maximum strain under 6.5 MPa stress at 1400 ℃ decreases from 215 t.tm to 90 μm; residual strength ratio after 3 thermal shock cycles (1 100 ℃ , air quenching) decreases from 80% to 65%. This may be attributed to in-situ formation of nonoxides because Al and Si react with C, CO and N, to form Al4C3 , AlN and SiC creating strengthening and toughening effects.
基金This work was supported by Priority Research Centre Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education,Science,and Technology(NRF-2018R1A6A1A03024334)Also,this work was supported by Priority Research Centre Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education,Science,and Technology(2020R1A2C2004880).
文摘In the present investigation, we fabricated strontium (Sr2+) incorporated CsPbI2Br-based inorganic perovskite solar cells in ambient conditions. The morphology, crystallinity, absorption, elemental composition and photoluminescence analysis of the bare CsPbI2Br and CsPb1-xSrxI2Br perovskite thin films were studied systematically to investigate the role of Sr2+ incorporation. It is observed that the surface morphology of the CsPbI2Br perovskite thin film has been improved by partial substitution of Pb2+ by Sr2+ which facilitates photoactive black phase-stabilization and defect passivation. The champion device having CsPb0.98Sr0.02I2Br composition exhibited a power conversion efficiency (PCE) of 16.61% which is much higher than the bare device (13.65%). Furthermore, our CsPb0.98Sr0.02I2Br-based devices maintain > 85% of its initial efficiency over 100 h in ambient conditions.
基金supported by the National Natural Science Foundation of China(52172237,52072228)the Shaanxi International Cooperational Project(2020KWZ-018)+1 种基金the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(Grant No.2021-QZ-02)the Fundamental Research Funds for the Central Universities(3102019JC005)。
文摘All-inorganic CsPbI_(2)Br perovskite solar cells(PSCs)have received extensive research interests recently.Nevertheless,their low efficiency and poor long-term stability are still obstacles for further commercial application.Herein,we demonstrate that high efficiency and exceptional long-term stability are realized by incorporating gadolinium(III)chloride(GdCl_(3))into the CsPbI_(2)Br perovskite film.The incorporation of GdCl_(3) enhances the Goldschmidt tolerance factor of CsPbI_(2)Br perovskite,yielding a dense perovskite film with small grains,thus the a-phase CsPbI_(2)Br is remarkably stabilized.Additionally,it is found that the GdCl_(3)-incorporated perovskite film achieves suppressed charge recombination and appropriate energy level alignment compared with the pristine CsPbI_(2)Br film.The noticeable increment in efficiency from14.01%(control PSC)to 16.24%is achieved for GdCl_(3)-incorporated PSC.Moreover,the nonencapsulated GdCl_(3)-incorporated PSC exhibits excellent environmental and thermal stability,remaining over 91%or90%of the original efficiency after 1200 h aging at 40%relative humidity or 480 h heating at 85℃ in nitrogen glove box respectively.The encapsulated GdCl_(3)-incorporated PSC presents an improved operational stability with over 88%of initial efficiency under maximum power point(MPP)tracking at 45℃ for1000 h.This work presents an effective ion-incorporation approach for boosting efficiency and long-term stability of all-inorganic PSCs.
基金the National Science Foundation(No.DMR0097126)Thanks for good advice from Professor Feihe Huang.
文摘A convenient synthetic method with high yields for aryl-incorporated ditosylates by reaction of aryl-incorporated diols with TsCI in THF/NaOH/H2O solution was described. Some of these aryl-incorporated ditosylates reacted with diphenols to produce crown ethers in pleasant yield.
文摘This article reports a preliminary research on silicate-incorporated hydroxyapatite as a new environmental mineral used to remove cadmium ions from aqueous solutions. The silicate-incorporated hydroxyapatite was prepared by coprecipitation and calcining, and silicate was incorporated into the crystal lattice of hydroxyapatite by partial substitution of phosphate. The amount of cadmium ions removed by silicate-incorporated hydroxyapatite was significantly elevated, which was 76% higher than that of pure hydroxyapatite. But the sorption behavior of cadmium ions on silicate-incorporated hydroxyapatite was similar to that of pure hydroxyapatite. Morphological study revealed that silicate incorporation confined the crystal growth and increased the specific surface area of hydroxyapatite, which were in favor of enhancing the cadmium ion sorption capacity of the samples. Incorporation of silicate into hydroxyapatite seems to be an effective approach to improve the environmental property of hydroxyapatite on removal of aqueous cadmium ions.
基金Supported by the National Natural Science Foundation of China under Grant No 10332020
文摘Carbonaceous nanomaterials such as carbon nanotubes (CNTs), magnetic metal nanomaterials and semicon- ductor nanomaterials are superior candidates for microwave absorbers. Taking full advantage of the features of CNTs, nanophase cobalt and nanophase zinc oxide, whose main microwave absorption mechanisms are based on resistance loss, magnetic loss and dielectric loss, we fabricate CNT/Co and CNT/ZnO heterostructure nanocom- posites, respectively. By using the CNTs, CNT/Co nanocomposites and CNT/ZnO nanocomposites as nanofillers, composites with polyester as matrix are prepared by in situ polymerization, and their microwave absorption per- formance is studied. It is indicated that the synergetic effects of the physic properties of different components in nano-heterostructures result in greatly enhanced microwave absorption performance in a wide frequency range. The absorption peak is increased, the absorption bandwidth is broadened, and the maximum peak shifts to a lower frequency.
文摘Using cetyl-trimethyl-ammonium bromide (CTMAB) as template agent and tetraethylorthosilicate (TEOS) as silica Source, the MCM-41 mesoporous materials were synthesized with Y, Nd and Sm incorporated in the framework under hydrothermal conditions. The structure and the micro-morphology of the materials and the state of Y, Nd and Sm were investigated through the analyses of XRD, nitrogen adsorption-desorption isotherm, SEM, IR and TG-DTA. The XRD resuits indicate that the synthetic samples are of typical structure of mesoporous MCM-41 with ordered hexagonal arrangements, and Y, Nd and Sm can be incorporated into the framework of these mesoporous materials. Nitrogen adsorption-desorption isotherms show that the samples possess the typical mesopores character. SEM micrographs reveal that the incorporated samples show a well-defined spherical morphology with the diameter ranging 0.10 - 0.15μm. The occurrence of two different template sorption sites in the framework as revealed by TG-DTA analysis further suggests the presence of Y, Nd and Sm in siliceous framework.
文摘0 Introduction From a sociolinguistic perspective,competence in language use is determined not only by the ability to use language with grammatical accuracy,but also to use language appropriate to particular contexts.Thus,successful language learning requires language users to know the culture that underlies language.However,in foreign language teaching practice,culture teaching is often neglected,or introduced as no more than a supplementary diversion to language instruction.And the methods on how to teach the cultural knowledge is attached even less importance to.
文摘Four field trials were conducted over a three-year period (2011-2013) at various locations in Ontario to evaluate the level of weed control provided by halosulfuron applied PPI,PREor POST at 17.5, 35 and 70 g·ai·ha-1 in white bean. Halosulfuron applied PPI or PRE at 17.5, 35 and 35 g·ai·ha-1 caused 2% or less visible injury 1 and 4 WAA in white bean. However, halosulfuron applied POST at 17.5, 35 and 70 g·ai·ha-1 caused 2% - 8% and 1% - 3% white bean injury at 1 and 4 WAA, respectively. There was no decrease in white bean seed yield relative to the weed free check due to weed interference with halosulfuron applied PPI or PRE at doses evaluated, except when applied PRE at 17.5 g·ai·ha-1 which resulted in a decrease in seed yield of 25%. Weed interference caused a decrease in white bean yield of 47%, 42% and 44%, when halosulfuron was applied POST at 17.5, 35 and 70 g·ai·ha-1, respectively. Halosulfuron applied PPI, PRE and POST controlled AMARE 92% - 100%, 85% - 99% and 47% - 75%;CHEAL 95% - 100%, 83% - 99% and 36% - 51%;and SINAR 97% - 100%, 99% - 100% and 100%, respectively. Halosulfuron applied PPI and PRE reduced AMARE density 93% - 97% and 75% - 95%;CHEAL density 89% - 98% and 81% - 93%;and SINAR density 99% - 100% and 99% - 100%, respectively. Halosulfuron applied PPI and PRE reduced dry weight of AMARE 96% - 98% and 86% - 96%;CHEAL 96% - 98% and 87% - 93%;and SINAR 100% and 100%, respectively. Halosulfuron applied POST at rates evaluated reduced SINAR density and dry weight 100% but caused no significant reduction in AMARE and CHEAL density or dry weight compared to the weedy check. Based on these results, halosulfuron applied PPI orPREat 35 g·ai·ha-1 can be used safely for the control of selected broadleaf weeds in white bean production.
文摘The Zeolite Y as a support was modified by the incorporating of Fe and TiO2 in one single step using impregnation method. The synergistic effects between those components enhance the catalytic activity for the degradation of amaranth dye under ultrasonic irradiation with output power of 50 W and 40 kHz frequency. Different characterization techniques were used to elucidate the physical and chemical properties of the produced catalysts. The XRD results indicated that the type of titanium precursor significantly effects on the crystallinity of 0.4% Fe/15%TiO2-NaY catalyst. The AFM results detected that the TiO2 formed a layer covered the surface of zeolite while Fe clusters were located close to TiO2. The influence of reaction parameters such as TiO2 and Fe content, pH values, amount of hydrogen peroxide used, catalyst loading and the initial dye concentration were investigated for the decolorization efficiency of amaranth. The maximum decolorization efficiency for 0.4%Fe/15%TiO2-NaY was 100% after 120 min of reaction time with an initial dye concentration of 30 mg/L, 2 g/L of catalyst loading, natural pH about 5.5 and 0.65 mM H2O2.
基金supported by the National Natural Science Foundation of China(No.22108043)Natural Science Foundation of Guangdong Province,China(No.2023A1515012711).
文摘Cobalt-rich perovskite oxides play a paramount role in catalyzing oxygen evolution reaction(OER)on account of their acceptable intrinsic activity but are still challenging due to the high costs and undesired stability.In response to the defects,herein,the Mg-incorporated perovskite cobaltite SrCo_(0.6)Fe_(0.3M)g_(0.1)O_(3-δ)(SCFM-0.1)is proposed as a novel earth-abundant and durable OER electrocatalyst.A well-consolidated cubic-symmetry structure and more active oxygen intermediates are enabled upon Mg substitution.Hence,the optimized SCFM-0.1 perovskite oxide achieves prominent OER electrocatalytic performance,that is,a low overpotential of only 320 mV at 10 mA cm^(-2),a small Tafel slope of 65 mV dec^(-1),as well as an outstanding durability within 20 h,substantially outperforming that of the pristine SrCo_(0.7)Fe_(0.3)O_(3-δ)and benchmark Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ)and IrO_(2) catalysts.The strong pHdependent behavior associated with lattice oxygen activation mechanism for SCFM-0.1 catalyst is also confirmed.This work paves a unique avenue to develop cost-effective and robust perovskite cobaltites for efficient OER electrocatalysis.
文摘The immobilization of SiW_(12)O_(40)^(4-)in poly(4-aminoazobenzene)film was done by electrochemical method.According to the continuous cyclic voltammograms of the modified electrode,it can be determined that SiW_(12)O_(40)^(4-) in the polymer is very stable.The paper reports the elecctrochemical pro- perties of the modified electrode,Moreover,it was found that the modified electrode exhibits electrocatalysis for the reaction of oxygen.
文摘Several gelatin-silicate composites, with or without incorporation of Ca2+ ions, were synthesized through sol-gel processing starting from gelatin and 3- (glycidoxypropyl) trimethoxysilane. The structure around the Si atoms was similar for all the samples. The measurement of viscoelastic properties indicated that the glass transition temperature and activation energy decreased with the incorporation of Ca2+ ions. The Ca2+ ion-containing composites were bioactive as they spontaneously deposited apatite when soaked in a simulated body fluid of the Kokubo recipe.
文摘Recent price movement Most benchmark prices decreased over the past month. Chinese prices moved sharply lower.Open interest has shifted from July and into the December contract. After moving lower in early May, values for the July contract were volatile but rangebound between 65 and 70 cents/lb for most of the past month. Values for the December contract also moved lower in early May. While they had been rangebound, December prices have been testing the lower end of their recent range, briefly dropping below 65 cents/lb in the latest trading.
文摘Recent price movement Benchmark prices were flat or slightly higherover the pastmonth. Prices for the May NY futures contract increased over past month,climbing from levels just below 70 cents/lb in mid-February to those near 74 cents/lb recently.