Aqueous zinc(Zn)batteries with Zn metal anodes are promising clean energy storage devices with intrinsic safety and low cost.However,Zn dendrite growth severely restricts the use of Zn anodes.To effectively suppress Z...Aqueous zinc(Zn)batteries with Zn metal anodes are promising clean energy storage devices with intrinsic safety and low cost.However,Zn dendrite growth severely restricts the use of Zn anodes.To effectively suppress Zn dendrite growth,we propose a bilayer separator consisting of commercial butter paper and glassfiber membrane.The dense cellulose-based butter paper(BP)with low zincophilicity and high mechanical properties prevents the pore-filling behavior of deposited Zn and related separator piercing,effectively suppressing the Zn dendrite growth.As a result,the bilayer separators endow the ZnjjZn symmetrical batteries with a superlong cycling life of Zn anodes(over 5000 h)at 0.5 mA cm^(-2) and the full batteries enhanced capacity retention,demonstrating the advancement of the bilayer separator to afford excellent cyclability of aqueous metal batteries.展开更多
Carbendazim,belonging to fungicides,was commonly used for controlling crop diseases,resulting in frequent residues in fruits and vegetables.Washing was the initial step of household fruit processing for cleaning and r...Carbendazim,belonging to fungicides,was commonly used for controlling crop diseases,resulting in frequent residues in fruits and vegetables.Washing was the initial step of household fruit processing for cleaning and reducing pollutant contents.However,the effect of washing on the removal of carbendazim in apples was not systemically studied.Thus,in this study,an analytical method was firstly established for the determination of carbendazim with great accuracy and precision through quick,simple,cheap,effective and safe(QuEChERS)method and ultra-performance liquid chromatography-fluorescence detection(UPLC-FLD).Then,the influencing factors were systematically researched to unveil their effects on the carbendazim residue in apples.The results indicated that water temperature,washing products and washing method could obviously affect the carbendazim content in apples.In addition,the best cleaning scheme for removal of carbendazim was soaking apples for 5 min in a cleaning solution,which was prepared by dissolving 8 g of commercial fruit washing soup with 500 ml of water at 45℃.Under this condition,the removal rate of carbendazim in the washing step reached 73.91%.This study will be helpful for providing guidance for household cleaning methods for controlling pesticide residues.展开更多
Optical coherence tomography angiography(OCTA)takes the flowing red blood cells(RBCs)as intrinsic contrast agents,enabling fast and three-dimensional visualization of vasculature per-fusion down to capillary level,wit...Optical coherence tomography angiography(OCTA)takes the flowing red blood cells(RBCs)as intrinsic contrast agents,enabling fast and three-dimensional visualization of vasculature per-fusion down to capillary level,without a requirement of exogenous fluorescent injection.Various motion-contrast OCTA algorithms have been proposed to effectively extract dynamic blood flow from static tissues utilizing the different components of OCT signals(including amplitude,phase and complex)with various operations(such as differential,variance and decorrelation).Those algorithms promote the application of OCTA in both clinical diagnosis and scientific research.The purpose of this paper is to provide a systematical review of OCTA based on the inverse SNR and decorrelation features(ID-OCTA),mainly including the OCTA contrast origins,ID-OCTA imaging,quantification and applications.展开更多
Electrochemical catalysts for oxygen evolution reaction are a critical component for many renewable energy applications. To improve their catalytic kinetics and mass activity are essential for sustainable industrial a...Electrochemical catalysts for oxygen evolution reaction are a critical component for many renewable energy applications. To improve their catalytic kinetics and mass activity are essential for sustainable industrial applications. Here, we report a rare-earth metal-based oxide electrocatalyst comprised of ultrathin amorphous La2O3 nanosheets hybridized with uniform La2O3 nanoparticles(La2O3@NP-NS). Significantly improved OER performance is observed from the nanosheets with a nanometer-scale thickness. The as-synthesized 2.27-nm La2O3@NP-NS exhibits excellent catalytic kinetics with an overpotential of 310 mV at 10 m A cm^-2, a small Tafel slope of 43.1 mV dec^-1, and electrochemical impedance of 38 Ω. More importantly, due to the ultrasmall thickness, its mass activity, and turnover frequency reach as high as 6666.7 A g^-1 and 5.79 s^-1, respectively, at an overpotential of 310 mV. Such a high mass activity is more than three orders of magnitude higher than benchmark OER electrocatalysts, such as IrO2 and RuO2. This work presents a sustainable approach toward the development of highly e cient electrocatalysts with largely reduced mass loading of precious elements.展开更多
To accurately guide surgical instruments during ophthalmic procedures,some necessary intraoperative depth perception is required,which standard surgical microscopes supply limit-edly.Intraoperative optical coherence t...To accurately guide surgical instruments during ophthalmic procedures,some necessary intraoperative depth perception is required,which standard surgical microscopes supply limit-edly.Intraoperative optical coherence tomography(iOCT),combining optical coherence to-mography(OCT)technology and surgical microscope,enables noninvasive,real-time and high-resolution cross-sectional imaging.Currently,though iOCT enables structural imaging,little research has been done on intraoperative angiography.In this work,we presented a swept-source intraoperative OCT angiography(SS-iOCTA)system based on a standard surgical microscope,which provides both structural and angiographic images.The feasibility of the proposed SS-iOCTA was confirmed through deep anterior lamellar keratoplasty(DALK)of ex vivo porcine eyes and blood perfusion imaging of in vivo rat cortex.High-resolution intraoperative feedback,including sub-surface structure and angiogram of biological tissue,can be visualized simulta-neously with the SS-iOCTA system,which expand the surgeon's capabilities and could be widely used in clinical surgery.展开更多
Comprehensive Summary,Regulating spin crossover(SCO)behavior,especially controlling the spin transition steps,is an important scientific issue,mainly because people aim to control spin bistability and multistability.P...Comprehensive Summary,Regulating spin crossover(SCO)behavior,especially controlling the spin transition steps,is an important scientific issue,mainly because people aim to control spin bistability and multistability.Presently,SCO bistability can be regulated by changing the ligand-modifying species,non-coordinated anions,guest molecules,and metal-ion dopant.However,the control of multistability is extremely challenging,especially in Fe(III)SCO compounds.Here,we report that[FeIII(H-5-Br-thsa)(5-Br-thsa)]·H2O(5-Br-thsa=(5-bromo-2-hydroxybenzylidene)hydrazinecarbothioamide),a compound we have reported before,exists in two polymorphic forms:polymorph 1 exhibits three-step SCO,and polymorph 2 shows five-step SCO,with multi-step SCO behavior effectively regulated by polymorphism.According to single-crystal and powder X-ray diffractometry,polymorphs 1 and 2 crystallize in different space groups during their spin transitions,with two-step symmetry breaking observed(Pbcn→Pnc2→Pbcn for polymorph 1;P21/n→Pn→P21/n for polymorph 2).We realized that the behavior of these two polymorphs depends significantly on the structure,including(i)the average Fe—N bond distance,(ii)deformation of octahedral FeIII atoms,and(iii)distinct crystal packing,which account for the large differences observed in magnetic properties.展开更多
Heterocyclic aramid fibers,a typical kind of high-performance fibers,have been widely used in aerospace and protection fields because of their excellent mechanical properties.However,the application of heterocyclic ar...Heterocyclic aramid fibers,a typical kind of high-performance fibers,have been widely used in aerospace and protection fields because of their excellent mechanical properties.However,the application of heterocyclic aramid fibers as a reinforcement is hindered by the weak interfacial combination with matrix materials,especially epoxy.Traditional strategies enhancing the interfacial shear strength(IFSS)usually decrease the tensile strength.Therefore,simultaneous enhancement of both mechanical properties remains a challenge.Herein,we report a novel heterocyclic aramid fiber with high interfacial shear strength(49.3 MPa)and tensile strength(6.27 GPa),in which 4,4′-diamino-2′-chlorobenzanilide(DABA-Cl)and a small amount of graphene oxide(GO)are introduced through in-situ polymerization.Hydrogen bonds andπ–πinteraction between GO and polymer chains trigger the enhancement in crystallinity,orientation,and lateral interaction of the fibers,thus improving the tensile strength and interfacial shear strength of the fibers.Moreover,the interfacial interaction between fiber and epoxy is enhanced due to the improvement of the surface polarity of the fibers caused by DABA-Cl.Therefore,a method to improve both tensile strength and interfacial shear strength of heterocyclic aramid fibers was found by introducing GO and DABA-Cl,which may provide guidance for the design and preparation of other high-performance fibers.展开更多
Photodynamic therapy(PDT)by near-infrared(NIR)irradiation is a promising technique for treating various cancers.Here,we reported the development of free-standing wafer-scale Au nanosheets(NSs)that exhibited an impress...Photodynamic therapy(PDT)by near-infrared(NIR)irradiation is a promising technique for treating various cancers.Here,we reported the development of free-standing wafer-scale Au nanosheets(NSs)that exhibited an impressive PDT effect.The Au NSs were synthesized by ionic layer epitaxy at the air-water interface with a uniform thickness in the range from 2 to 8.5 nm.These Au NSs were found very effective in generating singlet oxygen under NIR irradiation.In vitro cellular study showed that the Au NSs had very low cytotoxicity and high PDT efficiency due to their uniform 2D morphology.Au NSs could kill cancer cells after 5 min NIR irradiation with little heat generation.This performance is comparable to using 10 times mass loading of Au nanoparticles(NPs).This work suggests that two-dimensional(2D)Au NSs could be a new type of biocompatible nanomaterial for PDT of cancer with an extraordinary photon conversion and cancer cell killing efficiency.展开更多
Casi2b/C2ci is a newly identified class 2 CRISPR endonuclease that was recently engineered for targeted genome editing in mammals and rice.To explore the potential applications of the CRISPR-Casi2b system in the dicot...Casi2b/C2ci is a newly identified class 2 CRISPR endonuclease that was recently engineered for targeted genome editing in mammals and rice.To explore the potential applications of the CRISPR-Casi2b system in the dicot Arabidopsis thaliana,we selected BvCasi2b and BhCasi2b v4 for analysis.We successfully used both endonucleases to induce mutations,perform multiplex genome editing,and create large deletions at multiple loci.No significant mutations were detected at potential off-target sites.Analysis of the insertion/deletion frequencies and patterns of mutants generated via targeted gene mutagenesis highlighted the potential utility of CRISPRCasi2b systems for genome editing in Arabidopsis.展开更多
of main observation and conclusion Sustainable phytic acid and cellulose are selected as precursors to fabricate P-doped carbon material(C-P-500),which possesses the high surface area and exhibits excellent catalytic ...of main observation and conclusion Sustainable phytic acid and cellulose are selected as precursors to fabricate P-doped carbon material(C-P-500),which possesses the high surface area and exhibits excellent catalytic activity and stability in the oxidative coupling of benzylamines(conversion>95%,yield>95%).During the carbonization of cellulose in the muffle furnace,phytic acid can efficiently prevent the cellulose-derived carbon from combustion and create micro/meso porous structure because of its special function of fire retardation.Control experiments and characterizations demonstrate that P-containing groups anchoring on C-P-500 improve the catalytic performance of carbocatalyst in the oxidation of benzylamines to imines.The excellent catalytic activity of C-P-500 should be contributed collectively by carbonyl and P=0(0H)2 groups.Due to the sustainable property of precursors and simple methodology for fabricating P-doped carbocatalyst,along with the moderate reaction conditions,it is a green catalytic system for the oxidative coupling of benzylamines to imines.展开更多
In this paper,we apply the structural vector autoregression(SVAR)model to decompose the international oil price shock into oil supply shocks,aggregate demand shocks and oil-specific demand shocks,and then use the DCC-...In this paper,we apply the structural vector autoregression(SVAR)model to decompose the international oil price shock into oil supply shocks,aggregate demand shocks and oil-specific demand shocks,and then use the DCC-GARCH model to analyse the dynamic correlations between these three kinds of oil price shocks and the macroeconomic variables of several oil importing and exporting countries.To quantify the intensity of the effect of oil shocks on these variables,we propose a measure,conditional expectation(Co E),to capture the percent change of the economic variable under oil price shocks relative to the median state.The time-varying copula model is employed to estimate the proposed measure through time.The empirical results show that,for instance,the impacts of oil price shocks on macroeconomic variables are different in different periods,showing the time-varying characteristics.Additionally,the impacts of oil price shocks on macroeconomic variables show great differences and some similarities among different countries.Finally,we give some policy suggestions for these countries,in particular for China’s special results.展开更多
基金supported by grants from the National Key Research and Development Program of China(No.2021YFF0500600)the Haihe Laboratory of Sustainable Chemical Transformations,and the Fundamental Research Funds for the Central Universities.We appreciate Neware Technology Co.,Ltd for their battery test systems in the TJU Nanoyang-Neware Joint Laboratory for Energy Innovation.
文摘Aqueous zinc(Zn)batteries with Zn metal anodes are promising clean energy storage devices with intrinsic safety and low cost.However,Zn dendrite growth severely restricts the use of Zn anodes.To effectively suppress Zn dendrite growth,we propose a bilayer separator consisting of commercial butter paper and glassfiber membrane.The dense cellulose-based butter paper(BP)with low zincophilicity and high mechanical properties prevents the pore-filling behavior of deposited Zn and related separator piercing,effectively suppressing the Zn dendrite growth.As a result,the bilayer separators endow the ZnjjZn symmetrical batteries with a superlong cycling life of Zn anodes(over 5000 h)at 0.5 mA cm^(-2) and the full batteries enhanced capacity retention,demonstrating the advancement of the bilayer separator to afford excellent cyclability of aqueous metal batteries.
基金Supported by Course Construction Project of Huanggang Normal University(2022KC20)Training Program of the Major Research Plan of Huanggang Normal University(202211604).
文摘Carbendazim,belonging to fungicides,was commonly used for controlling crop diseases,resulting in frequent residues in fruits and vegetables.Washing was the initial step of household fruit processing for cleaning and reducing pollutant contents.However,the effect of washing on the removal of carbendazim in apples was not systemically studied.Thus,in this study,an analytical method was firstly established for the determination of carbendazim with great accuracy and precision through quick,simple,cheap,effective and safe(QuEChERS)method and ultra-performance liquid chromatography-fluorescence detection(UPLC-FLD).Then,the influencing factors were systematically researched to unveil their effects on the carbendazim residue in apples.The results indicated that water temperature,washing products and washing method could obviously affect the carbendazim content in apples.In addition,the best cleaning scheme for removal of carbendazim was soaking apples for 5 min in a cleaning solution,which was prepared by dissolving 8 g of commercial fruit washing soup with 500 ml of water at 45℃.Under this condition,the removal rate of carbendazim in the washing step reached 73.91%.This study will be helpful for providing guidance for household cleaning methods for controlling pesticide residues.
基金The authors are thankful to National Natural Science Foundation of China(62075189)Zhejiang Provincial Natural Science Foundation of China(LR19F050002)+1 种基金Zhejiang Lab(2018EBOZX01)Fundamental Research Funds for the Central Universities(2018FZA5003).
文摘Optical coherence tomography angiography(OCTA)takes the flowing red blood cells(RBCs)as intrinsic contrast agents,enabling fast and three-dimensional visualization of vasculature per-fusion down to capillary level,without a requirement of exogenous fluorescent injection.Various motion-contrast OCTA algorithms have been proposed to effectively extract dynamic blood flow from static tissues utilizing the different components of OCT signals(including amplitude,phase and complex)with various operations(such as differential,variance and decorrelation).Those algorithms promote the application of OCTA in both clinical diagnosis and scientific research.The purpose of this paper is to provide a systematical review of OCTA based on the inverse SNR and decorrelation features(ID-OCTA),mainly including the OCTA contrast origins,ID-OCTA imaging,quantification and applications.
基金supported by Army Research O ce(ARO)under Grant W911NF-16-1-0198the National Science Foundation(DMR-1709025)China Scholarship Council
文摘Electrochemical catalysts for oxygen evolution reaction are a critical component for many renewable energy applications. To improve their catalytic kinetics and mass activity are essential for sustainable industrial applications. Here, we report a rare-earth metal-based oxide electrocatalyst comprised of ultrathin amorphous La2O3 nanosheets hybridized with uniform La2O3 nanoparticles(La2O3@NP-NS). Significantly improved OER performance is observed from the nanosheets with a nanometer-scale thickness. The as-synthesized 2.27-nm La2O3@NP-NS exhibits excellent catalytic kinetics with an overpotential of 310 mV at 10 m A cm^-2, a small Tafel slope of 43.1 mV dec^-1, and electrochemical impedance of 38 Ω. More importantly, due to the ultrasmall thickness, its mass activity, and turnover frequency reach as high as 6666.7 A g^-1 and 5.79 s^-1, respectively, at an overpotential of 310 mV. Such a high mass activity is more than three orders of magnitude higher than benchmark OER electrocatalysts, such as IrO2 and RuO2. This work presents a sustainable approach toward the development of highly e cient electrocatalysts with largely reduced mass loading of precious elements.
基金National Natural Science Foundation of China(62075189 and 81873911)Zhejiang Provincial Natural Science Foundation of China(LR19F050002)+1 种基金Zhejiang Lab(2018EBOZX01)Fundamental Research Funds for the Central Universities(2018FZA5003).
文摘To accurately guide surgical instruments during ophthalmic procedures,some necessary intraoperative depth perception is required,which standard surgical microscopes supply limit-edly.Intraoperative optical coherence tomography(iOCT),combining optical coherence to-mography(OCT)technology and surgical microscope,enables noninvasive,real-time and high-resolution cross-sectional imaging.Currently,though iOCT enables structural imaging,little research has been done on intraoperative angiography.In this work,we presented a swept-source intraoperative OCT angiography(SS-iOCTA)system based on a standard surgical microscope,which provides both structural and angiographic images.The feasibility of the proposed SS-iOCTA was confirmed through deep anterior lamellar keratoplasty(DALK)of ex vivo porcine eyes and blood perfusion imaging of in vivo rat cortex.High-resolution intraoperative feedback,including sub-surface structure and angiogram of biological tissue,can be visualized simulta-neously with the SS-iOCTA system,which expand the surgeon's capabilities and could be widely used in clinical surgery.
基金supported by the National Natural Science Foundation of China(NSFC,21971124,22275100,22150710513)the Ph.D.Candidate Research Innovation Fund of the NkU School of Materials Science and Engineering.
文摘Comprehensive Summary,Regulating spin crossover(SCO)behavior,especially controlling the spin transition steps,is an important scientific issue,mainly because people aim to control spin bistability and multistability.Presently,SCO bistability can be regulated by changing the ligand-modifying species,non-coordinated anions,guest molecules,and metal-ion dopant.However,the control of multistability is extremely challenging,especially in Fe(III)SCO compounds.Here,we report that[FeIII(H-5-Br-thsa)(5-Br-thsa)]·H2O(5-Br-thsa=(5-bromo-2-hydroxybenzylidene)hydrazinecarbothioamide),a compound we have reported before,exists in two polymorphic forms:polymorph 1 exhibits three-step SCO,and polymorph 2 shows five-step SCO,with multi-step SCO behavior effectively regulated by polymorphism.According to single-crystal and powder X-ray diffractometry,polymorphs 1 and 2 crystallize in different space groups during their spin transitions,with two-step symmetry breaking observed(Pbcn→Pnc2→Pbcn for polymorph 1;P21/n→Pn→P21/n for polymorph 2).We realized that the behavior of these two polymorphs depends significantly on the structure,including(i)the average Fe—N bond distance,(ii)deformation of octahedral FeIII atoms,and(iii)distinct crystal packing,which account for the large differences observed in magnetic properties.
基金supported by the National Key Plan for Scientific Research and Development of China(2020YFA0509304 and 2021YFA0805300)the Chinese Academy of Sciences(XDB39000000)+3 种基金the National Natural Science Foundation of China(82030034,32121002,and 81971123)CAMS Innovation Fund for Medical Sciences(2021-I2M-C&T-B-012)the Fundamental Research Funds for the Central Universities(YD9110002027)the Guangzhou Key Research Program on Brain Science(202007030008)。
基金the Ministry of Science and Technology of China(No.2016YFA0200100)the Beijing National Laboratory for Molecular Sciences(No.BNLMS-CXTD-202001)+1 种基金the National Natural Science Foundation of China(Nos.52102035,52021006,T2188101,51720105003,and 21790052)the Strategic Priority Research Program of CAS(No.XDB36030100).
文摘Heterocyclic aramid fibers,a typical kind of high-performance fibers,have been widely used in aerospace and protection fields because of their excellent mechanical properties.However,the application of heterocyclic aramid fibers as a reinforcement is hindered by the weak interfacial combination with matrix materials,especially epoxy.Traditional strategies enhancing the interfacial shear strength(IFSS)usually decrease the tensile strength.Therefore,simultaneous enhancement of both mechanical properties remains a challenge.Herein,we report a novel heterocyclic aramid fiber with high interfacial shear strength(49.3 MPa)and tensile strength(6.27 GPa),in which 4,4′-diamino-2′-chlorobenzanilide(DABA-Cl)and a small amount of graphene oxide(GO)are introduced through in-situ polymerization.Hydrogen bonds andπ–πinteraction between GO and polymer chains trigger the enhancement in crystallinity,orientation,and lateral interaction of the fibers,thus improving the tensile strength and interfacial shear strength of the fibers.Moreover,the interfacial interaction between fiber and epoxy is enhanced due to the improvement of the surface polarity of the fibers caused by DABA-Cl.Therefore,a method to improve both tensile strength and interfacial shear strength of heterocyclic aramid fibers was found by introducing GO and DABA-Cl,which may provide guidance for the design and preparation of other high-performance fibers.
基金This work was supported by the Army Research Office(No.W911NF-16-1-0198)the National Science Foundation(No.DMR-1709025)+2 种基金National Institutes of Health(Nos.R01EB0213360,1R21EB027857,and P30CA014520)Diffraction data was collected at ChemMatCARS Sector 15,which is principally supported by the Divisions of Chemistry and Materials Research,National Science Foundation,under grant number NSF/CHE-1834750Use of the Advanced Photon Source,an Office of Science User Facility operated for the U.S.Department of Energy(DOE)Office of Science by Argonne National Laboratory,was supported by the U.S.DOE(No.DEAC02-06CH11357).
文摘Photodynamic therapy(PDT)by near-infrared(NIR)irradiation is a promising technique for treating various cancers.Here,we reported the development of free-standing wafer-scale Au nanosheets(NSs)that exhibited an impressive PDT effect.The Au NSs were synthesized by ionic layer epitaxy at the air-water interface with a uniform thickness in the range from 2 to 8.5 nm.These Au NSs were found very effective in generating singlet oxygen under NIR irradiation.In vitro cellular study showed that the Au NSs had very low cytotoxicity and high PDT efficiency due to their uniform 2D morphology.Au NSs could kill cancer cells after 5 min NIR irradiation with little heat generation.This performance is comparable to using 10 times mass loading of Au nanoparticles(NPs).This work suggests that two-dimensional(2D)Au NSs could be a new type of biocompatible nanomaterial for PDT of cancer with an extraordinary photon conversion and cancer cell killing efficiency.
基金This work was supported by the National Natural Science Foundation of China(31570190,31800224)the Science Technology and Innovation Committee of Shenzhen Municipality(JCYJ20170303154319837,JCYJ20170412155447658)+1 种基金the Natural Science Foundation of Hebei Province(12017208087)the Science and Technology Research Program for Colleges and Universities in Hebei Province(QN2018149).
文摘Casi2b/C2ci is a newly identified class 2 CRISPR endonuclease that was recently engineered for targeted genome editing in mammals and rice.To explore the potential applications of the CRISPR-Casi2b system in the dicot Arabidopsis thaliana,we selected BvCasi2b and BhCasi2b v4 for analysis.We successfully used both endonucleases to induce mutations,perform multiplex genome editing,and create large deletions at multiple loci.No significant mutations were detected at potential off-target sites.Analysis of the insertion/deletion frequencies and patterns of mutants generated via targeted gene mutagenesis highlighted the potential utility of CRISPRCasi2b systems for genome editing in Arabidopsis.
基金We thank the following funders for financial supports of the National Natural Science Foundation of China(Nos.21603054,21773053)the Natural Science Foundation of Hebei Province(No.B2017201084)+1 种基金the One Hundred Talent Project of Hebei Province(No.E2016100015)the Advanced Talents Incubation Program of Hebei University(No.801260201019).
文摘of main observation and conclusion Sustainable phytic acid and cellulose are selected as precursors to fabricate P-doped carbon material(C-P-500),which possesses the high surface area and exhibits excellent catalytic activity and stability in the oxidative coupling of benzylamines(conversion>95%,yield>95%).During the carbonization of cellulose in the muffle furnace,phytic acid can efficiently prevent the cellulose-derived carbon from combustion and create micro/meso porous structure because of its special function of fire retardation.Control experiments and characterizations demonstrate that P-containing groups anchoring on C-P-500 improve the catalytic performance of carbocatalyst in the oxidation of benzylamines to imines.The excellent catalytic activity of C-P-500 should be contributed collectively by carbonyl and P=0(0H)2 groups.Due to the sustainable property of precursors and simple methodology for fabricating P-doped carbocatalyst,along with the moderate reaction conditions,it is a green catalytic system for the oxidative coupling of benzylamines to imines.
基金the National Natural Science Foundation of China(71571008,71271015)。
文摘In this paper,we apply the structural vector autoregression(SVAR)model to decompose the international oil price shock into oil supply shocks,aggregate demand shocks and oil-specific demand shocks,and then use the DCC-GARCH model to analyse the dynamic correlations between these three kinds of oil price shocks and the macroeconomic variables of several oil importing and exporting countries.To quantify the intensity of the effect of oil shocks on these variables,we propose a measure,conditional expectation(Co E),to capture the percent change of the economic variable under oil price shocks relative to the median state.The time-varying copula model is employed to estimate the proposed measure through time.The empirical results show that,for instance,the impacts of oil price shocks on macroeconomic variables are different in different periods,showing the time-varying characteristics.Additionally,the impacts of oil price shocks on macroeconomic variables show great differences and some similarities among different countries.Finally,we give some policy suggestions for these countries,in particular for China’s special results.