The access to high-density hydrocarbon fuels from biomass for the reduction of dependence on fossil resources has been a research highlight in recent years. It is well known that cycloalkanes are the components of fue...The access to high-density hydrocarbon fuels from biomass for the reduction of dependence on fossil resources has been a research highlight in recent years. It is well known that cycloalkanes are the components of fuels with higher energy density than straight or branched alkanes. Herein, we developed a new catalytic pattern to synthesize dimethyltetradecahydroanthracenes(DMTHA), a kind of tricyclic alkane, from biomass-derived isoprene and p-benzoquinone via a cascade Diels-Alder reaction followed by a hydrodeoxygenation reaction. Vanadium supported on titanium dioxide(V-TiO_(2)) was applied to catalyze the cascade Diels-Alder reaction and it was disclosed that V with appropriate V^(4+)/V^(5+) ratio on the surface of TiO_(2) could activate quinones. Experimental tests showed that the heating value of final products was up to 45.7 MJ/kg. The development of new high-density fuel molecules is a long-term trend for the future renewable and sustainable fuel energy application.展开更多
As a strong oxidizer,hypochlorite(Cl O^(-))are widely employed as bleaching agents and disinfectants.Determination of ClO^(-)is required to ensure bactericidal effects and avoid hazards caused by excessive residual ch...As a strong oxidizer,hypochlorite(Cl O^(-))are widely employed as bleaching agents and disinfectants.Determination of ClO^(-)is required to ensure bactericidal effects and avoid hazards caused by excessive residual chlorine.Herein,the derivative bicyclic 2-pyridone,namely DHIP-Py,was prepared successfully to establish a new ClO^(-)-quantitative method.The probe exhibits excellent Cl O^(-)selectivity over other ROS and anions/cations,high sensitivity(LOD=1.32μmol/L),fast response(<5 s),and wide-p H tolerance(pH4~10).Benefit from its good water solubility,DHIP-Py is well suited for water sample analysis and has been successfully applied to detect Cl O^(-)in real-world food and environmental samples,including tap water,bottled water and river water.The detection results were essentially identical to that of obtained from traditional DPD method.Moreover,visual detection of Cl O^(-)via filter paper-based solid sensor and imaging of ClO^(-)in Escherichia coli were also achieved by DHIP-Py.These satisfactory results demonstrate that this bicyclic 2-pyridone-based hypochlorite probe is a promising free chlorine chemosensor with great potential for analytical applications.展开更多
The inconsistent Hubble constant values derived from cosmic microwave background(CMB) observations and from local distance-ladder measurements may suggest new physics beyond the standard ΛCDM paradigm. It has been fo...The inconsistent Hubble constant values derived from cosmic microwave background(CMB) observations and from local distance-ladder measurements may suggest new physics beyond the standard ΛCDM paradigm. It has been found in earlier studies that, at least phenomenologically, non-standard recombination histories can reduce the ≥4σ Hubble tension to ~ 2σ.Following this path, we vary physical and phenomenological parameters in RECFAST, the standard code to compute ionization history of the universe, to explore possible physics beyond standard recombination. We find that the CMB constraint on the Hubble constant is sensitive to the hydrogen ionization energy and 2 s → 1 s two-photon decay rate, both of which are atomic constants, and is insensitive to other details of recombination. Thus, the Hubble tension is very robust against perturbations of recombination history, unless exotic physics modifies the atomic constants during the recombination epoch.展开更多
In this work,we explore the cosmological consequences of the latest Type Ia supernova(SN Ia)dataset,Pantheon,by adopting the wCDM model.The Pantheon dataset currently contains the largest number of SN Ia samples,which...In this work,we explore the cosmological consequences of the latest Type Ia supernova(SN Ia)dataset,Pantheon,by adopting the wCDM model.The Pantheon dataset currently contains the largest number of SN Ia samples,which contains 1048 supernovae on the redshift range 0<z<2.3.Here we take into account three kinds of SN Ia statistics techniques,including:(1)magnitude statistics(MS),which is the traditional SN Ia statistics technique;(2)flux statistics(FS),which is based on the flux-averaging(FA)method;and(3)improved flux statistics(IFS),which combines the advantages of MS and FS.It should be mentioned that the IFS technique needs to scan the(zcut,Δz)parameters plane,where zcut andΔz are redshift cut-off and redshift interval of FA,respectively.The results are as follows.(1)Using the SN dataset only,the best FA recipe for IFS is(zcut,Δz)=(0.1,0.08);(2)comparing to the old SN dataset,JLA,adopting the Pantheon dataset can reduce the 2σerror bars of equation of state w by 38%,47%and 53%for MS,FS and IFS,respectively;(3)FS gives closer results to other observations,such as Baryon acoustic oscillations and cosmic microwave background;(4)compared with FS and IFS,MS more favors a Universe that will end in a‘big rip’.展开更多
基金the National Key R&D Program of China (2019YFC1905303, 2018YFB1501600)the National Natural Science Foundation of China (21908218, 21872139)DICP Grant (I201944) for providing financial support to do this scientific research。
文摘The access to high-density hydrocarbon fuels from biomass for the reduction of dependence on fossil resources has been a research highlight in recent years. It is well known that cycloalkanes are the components of fuels with higher energy density than straight or branched alkanes. Herein, we developed a new catalytic pattern to synthesize dimethyltetradecahydroanthracenes(DMTHA), a kind of tricyclic alkane, from biomass-derived isoprene and p-benzoquinone via a cascade Diels-Alder reaction followed by a hydrodeoxygenation reaction. Vanadium supported on titanium dioxide(V-TiO_(2)) was applied to catalyze the cascade Diels-Alder reaction and it was disclosed that V with appropriate V^(4+)/V^(5+) ratio on the surface of TiO_(2) could activate quinones. Experimental tests showed that the heating value of final products was up to 45.7 MJ/kg. The development of new high-density fuel molecules is a long-term trend for the future renewable and sustainable fuel energy application.
基金financially supported by the National Natural Science Foundation of China(No.21877082)the International Science and Technology Innovation Cooperation Project of Sichuan Province(No.2021YFH0132)+1 种基金the Sichuan Science and Technology Program(No.2021YFG0291)the Undergraduate Scientific and Technological Innovation Project(Nos.2021127,2021130),Xihua University。
文摘As a strong oxidizer,hypochlorite(Cl O^(-))are widely employed as bleaching agents and disinfectants.Determination of ClO^(-)is required to ensure bactericidal effects and avoid hazards caused by excessive residual chlorine.Herein,the derivative bicyclic 2-pyridone,namely DHIP-Py,was prepared successfully to establish a new ClO^(-)-quantitative method.The probe exhibits excellent Cl O^(-)selectivity over other ROS and anions/cations,high sensitivity(LOD=1.32μmol/L),fast response(<5 s),and wide-p H tolerance(pH4~10).Benefit from its good water solubility,DHIP-Py is well suited for water sample analysis and has been successfully applied to detect Cl O^(-)in real-world food and environmental samples,including tap water,bottled water and river water.The detection results were essentially identical to that of obtained from traditional DPD method.Moreover,visual detection of Cl O^(-)via filter paper-based solid sensor and imaging of ClO^(-)in Escherichia coli were also achieved by DHIP-Py.These satisfactory results demonstrate that this bicyclic 2-pyridone-based hypochlorite probe is a promising free chlorine chemosensor with great potential for analytical applications.
基金the Sun Yat-sen University Starting Grant for Research (Grant No. 71000-18841232)。
文摘The inconsistent Hubble constant values derived from cosmic microwave background(CMB) observations and from local distance-ladder measurements may suggest new physics beyond the standard ΛCDM paradigm. It has been found in earlier studies that, at least phenomenologically, non-standard recombination histories can reduce the ≥4σ Hubble tension to ~ 2σ.Following this path, we vary physical and phenomenological parameters in RECFAST, the standard code to compute ionization history of the universe, to explore possible physics beyond standard recombination. We find that the CMB constraint on the Hubble constant is sensitive to the hydrogen ionization energy and 2 s → 1 s two-photon decay rate, both of which are atomic constants, and is insensitive to other details of recombination. Thus, the Hubble tension is very robust against perturbations of recombination history, unless exotic physics modifies the atomic constants during the recombination epoch.
基金supported by the National Natural Science Foundation of China under Grant No.11405024the Fundamental Research Funds for the Central Universities under Grant No.16lgpy50。
文摘In this work,we explore the cosmological consequences of the latest Type Ia supernova(SN Ia)dataset,Pantheon,by adopting the wCDM model.The Pantheon dataset currently contains the largest number of SN Ia samples,which contains 1048 supernovae on the redshift range 0<z<2.3.Here we take into account three kinds of SN Ia statistics techniques,including:(1)magnitude statistics(MS),which is the traditional SN Ia statistics technique;(2)flux statistics(FS),which is based on the flux-averaging(FA)method;and(3)improved flux statistics(IFS),which combines the advantages of MS and FS.It should be mentioned that the IFS technique needs to scan the(zcut,Δz)parameters plane,where zcut andΔz are redshift cut-off and redshift interval of FA,respectively.The results are as follows.(1)Using the SN dataset only,the best FA recipe for IFS is(zcut,Δz)=(0.1,0.08);(2)comparing to the old SN dataset,JLA,adopting the Pantheon dataset can reduce the 2σerror bars of equation of state w by 38%,47%and 53%for MS,FS and IFS,respectively;(3)FS gives closer results to other observations,such as Baryon acoustic oscillations and cosmic microwave background;(4)compared with FS and IFS,MS more favors a Universe that will end in a‘big rip’.
