Climate change can intensify drought in many regions of the world and lead to more frequent drought events or altered cycles of soil water status.Therefore,it is important to enhance the tolerance to drought and thus ...Climate change can intensify drought in many regions of the world and lead to more frequent drought events or altered cycles of soil water status.Therefore,it is important to enhance the tolerance to drought and thus health,vigor,and success of transplantation seedlings used in the forestry by modifying fertilization and promoting mycorrhization.Here,we sowed seeds of Japanese larch(Larix kaempferi)in 0.2-L containers with 0.5 g(low fertilization;LF)or 2 g(high fertilization;HF)of slow-release fertilizer early in the growing season.One month later,we irrigated seedlings with non-sterilized ectomycorrhizal inoculum(ECM)or sterilized solution(non-ECM),and after about 2 months,plants were either kept well watered(WW;500 mL water/plant/week)or subjected to drought(DR;50 mL water per plant/week)until the end of the growing season.HF largely stimulated plant growth and above-and belowground biomass production,eff ects that are of practical signifi cance,but caused a small decrease in stomatal conductance(Gs 390)and transpiration rate(E 390),which in practice is insignifi cant.ECM treatment resulted in moderate inhibition of seedling growth and biomass and largely canceled out the enhancement of biomass and foliar K content by HF.DR caused a large decrease in CO 2 assimilation,and enhanced stomatal closure and induced senescence.DR also largely depleted foliar Mg and enriched foliar K.Although DR caused a large decrease in foliar P content in LF,it moderately increased P in HF.Likewise,DR increased foliar K in HF but not in LF,and decreased foliar P in ECM plants but not in non-ECM plants.Conversely,ECM plants exhibited a large enrichment in foliar P under WW and had a lower water potential under DR when grown in LF.These results indicate that the drought tolerance and health and vigor of Japanese larch seedlings can be modifi ed by soil fertility and soil microorganisms.This study provides a basis for new multifactorial research programs aimed at producing seedlings of superior quality for forestation under climate change.展开更多
The Bauschinger-like effect, which showed up in the straightening process of the AZ31 magnesium alloy wide sheet, was investigated through the multi-pass discrete three-point bending–unloading–bending(BUB) experimen...The Bauschinger-like effect, which showed up in the straightening process of the AZ31 magnesium alloy wide sheet, was investigated through the multi-pass discrete three-point bending–unloading–bending(BUB) experiments. The stress variable, anisotropy, and asymmetry of tension and compression on the straightening process were corresponding to the Bauschingerlike effect. The Bauschinger-like effect in the initial, intermediate, and end of the straightening process was dominated by the twinning, detwinning, and dislocation induced by pyramidal < c + a > slip, respectively. Also, they were responsible for the transformation of the Bauschinger stress parameter(BSP) and Bauschinger energy parameter(BEP). Later, the anisotropic nonlinear kinematic hardening model(ANK model) to describe the Bauschinger-like effect was optimized and simplified.展开更多
P values based on standard hypothesis testing are commonly reported in articles published by the Journal of Forestry Research(JFR).However,effect sizes are barely used and reported,even if they are of direct relevance...P values based on standard hypothesis testing are commonly reported in articles published by the Journal of Forestry Research(JFR).However,effect sizes are barely used and reported,even if they are of direct relevance to the primary questions of many of the published studies.The incorporation of effect sizes in studies published by JFR should be encouraged and promoted.Inclusion of effect sizes as a requirement in the journal guidelines will facilitate a major change in the way data are tested and interpreted,with the ultimate goal to exempt researchers from the custom of drawing conclusions merely based upon a dichotomous statistical result(P value).Such a policy can also lead to more informed decisions of whether identified effects are of practical relevance to the forestry.展开更多
The metal oxide/nitrogen-doped carbon(NC)compounds zirconium oxide/NC(ZrO_(2)/NC)and cerium oxide/NC(CeO_(2)/NC)were synthesized via the pyrolysis of polyaniline on the metal oxide surface.The characterization of the ...The metal oxide/nitrogen-doped carbon(NC)compounds zirconium oxide/NC(ZrO_(2)/NC)and cerium oxide/NC(CeO_(2)/NC)were synthesized via the pyrolysis of polyaniline on the metal oxide surface.The characterization of the ZrO_(2)/NC and CeO_(2)/NC catalysts showed more active CO_(2) reduction reaction activity than that of NC catalyst without metal oxide.Gas chromatography analysis revealed that CO and H_(2)were the primary products,and no liquid-phase products were detected via proton nuclear magnetic resonance spectroscopy or high-performance liquid chromatography.The maximum Faraday effi ciency of ZrO_(2)/NC reached 90%at−0.73 V(vs.RHE),with the current density of CO at 5.5 mA/cm^(2);this Faraday effi ciency value was higher than that of NC(41%),with the current density of CO at 3.1 mA/cm^(2).The interaction between the metal oxide and carbon allowed the effi cient formation of defect sites,especially imine-type nitrogen,strengthening the adsorption of the key reaction intermediate CO_(2)^(•−) and thus promoting the CO_(2) reduction reaction.展开更多
Electrocatalytic glucose oxidation reaction(GOR)has attracted much attention owing to its crucial role in biofuel cell fabrication.Herein,we load MoO_(3)nanoparticles on carbon nanotubes(CNTs)and use a discharge proce...Electrocatalytic glucose oxidation reaction(GOR)has attracted much attention owing to its crucial role in biofuel cell fabrication.Herein,we load MoO_(3)nanoparticles on carbon nanotubes(CNTs)and use a discharge process to prepare a noblemetal-free MC-60 catalyst containing MoO_(3),Mo_(2)C,and a Mo_(2)C–MoO_(3)interface.In the GOR,MC-60 shows activity as high as 745μA/(mmol/L cm^(2)),considerably higher than those of the Pt/CNT(270μA/(mmol/L cm^(2)))and Au/CNT catalysts(110μA/(mmol/L cm^(2))).In the GOR,the response minimum on MC-60 is as low as 8μmol/L,with a steady-state response time of only 3 s.Moreover,MC-60 has superior stability and anti-interference ability to impurities in the GOR.The better performance of MC-60 in the GOR is attributed to the abundant Mo sites bonding to C and O atoms at the MoO_(3)–Mo_(2)C interface.These Mo sites create active sites for promoting glucose adsorption and oxidation,enhancing MC-60 performance in the GOR.Thus,these results help to fabricate more effi cient noble-metal-free catalysts for the fabrication of glucose-based biofuel cells.展开更多
Inventory data were available from 96 plots of even-aged,monoculture,tall-open forests of Eucalyptus pilularis Smith,aged 2-63 years,growing in sub-tropical regions along the east coast of Australia.A model was develo...Inventory data were available from 96 plots of even-aged,monoculture,tall-open forests of Eucalyptus pilularis Smith,aged 2-63 years,growing in sub-tropical regions along the east coast of Australia.A model was developed relating the maximum possible stem basal area growth rate of individual trees to their stem basal area.For any tree size,this maximum increased as site productivity increased.However,the size at which this maximum occurred decreased as productivity increased.Much research has shown that,at any stand age,trees of a particular stem basal area are taller on more productive sites than on less productive ones.Taller trees incur greater respiratory costs to ensure maintenance of the photo synthetic capacity of their canopies;this reduces their growth rates.It was concluded that trees with larger basal areas will have the maximum possible growth rate on a less productive site,whilst trees with smaller basal areas will have the maximum possible on a more productive site.The model developed may constitute the first stage of a complete individual tree growth model system to predict wood yields from these forests.展开更多
Currently,the fault sliding speed functions or source–time functions used in theoretical seismogram calculations have only produced theoretical results;that is,the results of the fault speed–time functions have been...Currently,the fault sliding speed functions or source–time functions used in theoretical seismogram calculations have only produced theoretical results;that is,the results of the fault speed–time functions have been obtained only from theoretical studies,and have not been validated using the measured data.This paper signifi cantly improves the method for calculating fault sliding speed using the Doppler eff ect,from the following four perspectives.First,the paper theoretically demonstrates how to confirm that the seismic waves received in some frequency bands by two diff erent receivers are emitted by the same source.Second,the paper proposes a method to determine the similarity of seismic waves received by two diff erent receivers in some frequency bands;it applies the relative change at the two receivers in Fourier amplitude standard deviation in some frequency bands,and determines that similar seismic waves are emitted by the same frequency bands.Third,to eliminate the interference of reflected and refracted waves,this study uses fault sliding time S-wave records for data processing.Finally,the paper replaces the long-time Fourier transform with short-time Fourier transform to enhance the positioning accuracy of fault sliding times.Based on these perspectives,the paper systematically summarizes a general methodology for calculating the fault sliding speed using the Doppler effect.This method is employed to calculate the fault sliding speed of the Wenchuan earthquake;the calculations reveal that there is a general correlation between the fault sliding speeds of the Wenchuan earthquake and the seismic moment changes.The results confi rm that the sliding speed of the Wenchuan earthquake fault possesses the characteristics of abrupt change,whereby a sudden increase in the sliding speed is followed by a rapid decrease.Generally,the sliding speed is not fast,and sometimes,no sliding occurs.There are obvious diff erences from the currently used sliding speed functions,such as the Haskell function,bell-shaped function,exponential function,and triangular function.To determine the fault sliding speed using the Doppler eff ect,only the earthquake records and locations of the epicenter and receivers are required,instead of using unknown crust parameters.In short,the proposed calculation method has clear physical meaning,and the required parameters are easier to obtain.展开更多
Seismic force reduction factor(SFRF) spectra of shear-type multi-degree-of-freedom(MDOF) structures are investigated. The modified Clough model, capable of considering the strength-degradation/hardening and stiffnessd...Seismic force reduction factor(SFRF) spectra of shear-type multi-degree-of-freedom(MDOF) structures are investigated. The modified Clough model, capable of considering the strength-degradation/hardening and stiffnessdegradation, is adopted. The SFRF mean spectra using 102 earthquake records on a typical site soil type(type C) are constructed with the period abscissa being divided into three period ranges to maintain the peak features at the two sitespecific characteristic periods. Based on a large number of results, it is found that the peak value of SFRF spectra may also exist for MDOF, induced by large high-mode contributions to elastic base shear, besides the mentioned two peak values. The variations of the stiffness ratio λk and the strength ratio λF of the top to bottom story are both considered. It is found that the SFRFs for λF ≤λk are smaller than those for λF > λk. A SFRF modification factor for MDOF systems is proposed with respect to SDOF. It is found that this factor is significantly affected by the story number and ductility. With a specific λF(= λk0.75), SFRF mean spectra are constructed and simple solutions are presented for MDOF systems. For frames satisfying the strong column/weak beam requirement, an approximate treatment in the MDOF shear-beam model is to assign a post-limit stiffness 15%-35% of the initial stiffness to the hysteretic curve. SFRF spectra for MDOF systems with 0.2 and 0.3 times the post-limit stiffness are remarkably larger than those without post-limit stiffness. Thus, the findings that frames with beam hinges have smaller ductility demand are explained through the large post-limit stiffness.展开更多
基金supported by JSPS KAKENHI Grant Number JP17F17102 (to EA and MK)Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technology (NUIST)(No. 003080)the Jiangsu Distinguished Professor program of the People’s Government of Jiangsu Province
文摘Climate change can intensify drought in many regions of the world and lead to more frequent drought events or altered cycles of soil water status.Therefore,it is important to enhance the tolerance to drought and thus health,vigor,and success of transplantation seedlings used in the forestry by modifying fertilization and promoting mycorrhization.Here,we sowed seeds of Japanese larch(Larix kaempferi)in 0.2-L containers with 0.5 g(low fertilization;LF)or 2 g(high fertilization;HF)of slow-release fertilizer early in the growing season.One month later,we irrigated seedlings with non-sterilized ectomycorrhizal inoculum(ECM)or sterilized solution(non-ECM),and after about 2 months,plants were either kept well watered(WW;500 mL water/plant/week)or subjected to drought(DR;50 mL water per plant/week)until the end of the growing season.HF largely stimulated plant growth and above-and belowground biomass production,eff ects that are of practical signifi cance,but caused a small decrease in stomatal conductance(Gs 390)and transpiration rate(E 390),which in practice is insignifi cant.ECM treatment resulted in moderate inhibition of seedling growth and biomass and largely canceled out the enhancement of biomass and foliar K content by HF.DR caused a large decrease in CO 2 assimilation,and enhanced stomatal closure and induced senescence.DR also largely depleted foliar Mg and enriched foliar K.Although DR caused a large decrease in foliar P content in LF,it moderately increased P in HF.Likewise,DR increased foliar K in HF but not in LF,and decreased foliar P in ECM plants but not in non-ECM plants.Conversely,ECM plants exhibited a large enrichment in foliar P under WW and had a lower water potential under DR when grown in LF.These results indicate that the drought tolerance and health and vigor of Japanese larch seedlings can be modifi ed by soil fertility and soil microorganisms.This study provides a basis for new multifactorial research programs aimed at producing seedlings of superior quality for forestation under climate change.
基金financially supported by the National Key Research and Development Program of China(No.2016YFB0301104)the National Natural Science Foundation of China(No.51771043)the Programmer of Introducing Talents of Discipline Innovation to Universities 2.0(the 111 Project 2.0 of China,No.BP0719037)。
文摘The Bauschinger-like effect, which showed up in the straightening process of the AZ31 magnesium alloy wide sheet, was investigated through the multi-pass discrete three-point bending–unloading–bending(BUB) experiments. The stress variable, anisotropy, and asymmetry of tension and compression on the straightening process were corresponding to the Bauschingerlike effect. The Bauschinger-like effect in the initial, intermediate, and end of the straightening process was dominated by the twinning, detwinning, and dislocation induced by pyramidal < c + a > slip, respectively. Also, they were responsible for the transformation of the Bauschinger stress parameter(BSP) and Bauschinger energy parameter(BEP). Later, the anisotropic nonlinear kinematic hardening model(ANK model) to describe the Bauschinger-like effect was optimized and simplified.
基金co-supported by the Outstanding Action Plan of Chinese Sci-tech Journals(Grant No.OAP–C–077)the Startup Foundation for Introducing Talent of Nanjing University of Information Science&Technology(NUIST),Nanjing,China(Grant No.003080)the Jiangsu Distinguished Professor Program of the People’s Government of Jiangsu Province。
文摘P values based on standard hypothesis testing are commonly reported in articles published by the Journal of Forestry Research(JFR).However,effect sizes are barely used and reported,even if they are of direct relevance to the primary questions of many of the published studies.The incorporation of effect sizes in studies published by JFR should be encouraged and promoted.Inclusion of effect sizes as a requirement in the journal guidelines will facilitate a major change in the way data are tested and interpreted,with the ultimate goal to exempt researchers from the custom of drawing conclusions merely based upon a dichotomous statistical result(P value).Such a policy can also lead to more informed decisions of whether identified effects are of practical relevance to the forestry.
基金The work was supported by the National Key R&D Program of China(No.2016YFB0600901)Changyi Hydrogen Industrial Technology Fund.
文摘The metal oxide/nitrogen-doped carbon(NC)compounds zirconium oxide/NC(ZrO_(2)/NC)and cerium oxide/NC(CeO_(2)/NC)were synthesized via the pyrolysis of polyaniline on the metal oxide surface.The characterization of the ZrO_(2)/NC and CeO_(2)/NC catalysts showed more active CO_(2) reduction reaction activity than that of NC catalyst without metal oxide.Gas chromatography analysis revealed that CO and H_(2)were the primary products,and no liquid-phase products were detected via proton nuclear magnetic resonance spectroscopy or high-performance liquid chromatography.The maximum Faraday effi ciency of ZrO_(2)/NC reached 90%at−0.73 V(vs.RHE),with the current density of CO at 5.5 mA/cm^(2);this Faraday effi ciency value was higher than that of NC(41%),with the current density of CO at 3.1 mA/cm^(2).The interaction between the metal oxide and carbon allowed the effi cient formation of defect sites,especially imine-type nitrogen,strengthening the adsorption of the key reaction intermediate CO_(2)^(•−) and thus promoting the CO_(2) reduction reaction.
基金supported by the National Natural Science Foundation of China(Nos.82170426 and 22078193)Double Thousand Plan of Jiangxi Province(Nos.461654,jxsq2019102052).
文摘Electrocatalytic glucose oxidation reaction(GOR)has attracted much attention owing to its crucial role in biofuel cell fabrication.Herein,we load MoO_(3)nanoparticles on carbon nanotubes(CNTs)and use a discharge process to prepare a noblemetal-free MC-60 catalyst containing MoO_(3),Mo_(2)C,and a Mo_(2)C–MoO_(3)interface.In the GOR,MC-60 shows activity as high as 745μA/(mmol/L cm^(2)),considerably higher than those of the Pt/CNT(270μA/(mmol/L cm^(2)))and Au/CNT catalysts(110μA/(mmol/L cm^(2))).In the GOR,the response minimum on MC-60 is as low as 8μmol/L,with a steady-state response time of only 3 s.Moreover,MC-60 has superior stability and anti-interference ability to impurities in the GOR.The better performance of MC-60 in the GOR is attributed to the abundant Mo sites bonding to C and O atoms at the MoO_(3)–Mo_(2)C interface.These Mo sites create active sites for promoting glucose adsorption and oxidation,enhancing MC-60 performance in the GOR.Thus,these results help to fabricate more effi cient noble-metal-free catalysts for the fabrication of glucose-based biofuel cells.
文摘Inventory data were available from 96 plots of even-aged,monoculture,tall-open forests of Eucalyptus pilularis Smith,aged 2-63 years,growing in sub-tropical regions along the east coast of Australia.A model was developed relating the maximum possible stem basal area growth rate of individual trees to their stem basal area.For any tree size,this maximum increased as site productivity increased.However,the size at which this maximum occurred decreased as productivity increased.Much research has shown that,at any stand age,trees of a particular stem basal area are taller on more productive sites than on less productive ones.Taller trees incur greater respiratory costs to ensure maintenance of the photo synthetic capacity of their canopies;this reduces their growth rates.It was concluded that trees with larger basal areas will have the maximum possible growth rate on a less productive site,whilst trees with smaller basal areas will have the maximum possible on a more productive site.The model developed may constitute the first stage of a complete individual tree growth model system to predict wood yields from these forests.
基金supported by the Educational Department Project of Liaoning province:LJYL040(No.551610001219)。
文摘Currently,the fault sliding speed functions or source–time functions used in theoretical seismogram calculations have only produced theoretical results;that is,the results of the fault speed–time functions have been obtained only from theoretical studies,and have not been validated using the measured data.This paper signifi cantly improves the method for calculating fault sliding speed using the Doppler eff ect,from the following four perspectives.First,the paper theoretically demonstrates how to confirm that the seismic waves received in some frequency bands by two diff erent receivers are emitted by the same source.Second,the paper proposes a method to determine the similarity of seismic waves received by two diff erent receivers in some frequency bands;it applies the relative change at the two receivers in Fourier amplitude standard deviation in some frequency bands,and determines that similar seismic waves are emitted by the same frequency bands.Third,to eliminate the interference of reflected and refracted waves,this study uses fault sliding time S-wave records for data processing.Finally,the paper replaces the long-time Fourier transform with short-time Fourier transform to enhance the positioning accuracy of fault sliding times.Based on these perspectives,the paper systematically summarizes a general methodology for calculating the fault sliding speed using the Doppler effect.This method is employed to calculate the fault sliding speed of the Wenchuan earthquake;the calculations reveal that there is a general correlation between the fault sliding speeds of the Wenchuan earthquake and the seismic moment changes.The results confi rm that the sliding speed of the Wenchuan earthquake fault possesses the characteristics of abrupt change,whereby a sudden increase in the sliding speed is followed by a rapid decrease.Generally,the sliding speed is not fast,and sometimes,no sliding occurs.There are obvious diff erences from the currently used sliding speed functions,such as the Haskell function,bell-shaped function,exponential function,and triangular function.To determine the fault sliding speed using the Doppler eff ect,only the earthquake records and locations of the epicenter and receivers are required,instead of using unknown crust parameters.In short,the proposed calculation method has clear physical meaning,and the required parameters are easier to obtain.
基金Supported by:National Key Research and Development Program of China under Grant No.2016YFC0701201
文摘Seismic force reduction factor(SFRF) spectra of shear-type multi-degree-of-freedom(MDOF) structures are investigated. The modified Clough model, capable of considering the strength-degradation/hardening and stiffnessdegradation, is adopted. The SFRF mean spectra using 102 earthquake records on a typical site soil type(type C) are constructed with the period abscissa being divided into three period ranges to maintain the peak features at the two sitespecific characteristic periods. Based on a large number of results, it is found that the peak value of SFRF spectra may also exist for MDOF, induced by large high-mode contributions to elastic base shear, besides the mentioned two peak values. The variations of the stiffness ratio λk and the strength ratio λF of the top to bottom story are both considered. It is found that the SFRFs for λF ≤λk are smaller than those for λF > λk. A SFRF modification factor for MDOF systems is proposed with respect to SDOF. It is found that this factor is significantly affected by the story number and ductility. With a specific λF(= λk0.75), SFRF mean spectra are constructed and simple solutions are presented for MDOF systems. For frames satisfying the strong column/weak beam requirement, an approximate treatment in the MDOF shear-beam model is to assign a post-limit stiffness 15%-35% of the initial stiffness to the hysteretic curve. SFRF spectra for MDOF systems with 0.2 and 0.3 times the post-limit stiffness are remarkably larger than those without post-limit stiffness. Thus, the findings that frames with beam hinges have smaller ductility demand are explained through the large post-limit stiffness.
