Most previous studies on the market efficiency of cryptocurrencies consider time evolution but do not provide insights into the potential driving factors.This study addresses this limitation by examining the time-vary...Most previous studies on the market efficiency of cryptocurrencies consider time evolution but do not provide insights into the potential driving factors.This study addresses this limitation by examining the time-varying efficiency of the two largest cryptocurrencies,Bitcoin and Ethereum,and the factors that drive efficiency.It uses daily data from August 7,2016,to February 15,2023,the adjusted market inefficiency magnitude(AMIMs)measure,and quantile regression.The results show evidence of time variation in the levels of market(in)efficiency for Bitcoin and Ethereum.Interestingly,the quantile regressions indicate that global financial stress negatively affects the AMIMs measures across all quantiles.Notably,cryptocurrency liquidity positively and significantly affects AMIMs irrespective of the level of(in)efficiency,whereas the positive effect of money flow is significant when the markets of both cryptocurrencies are efficient.Finally,the COVID-19 pandemic positively and significantly affected cryptocurrency market inefficiencies across most quantiles.展开更多
Fourier transform infrared spectroscopy(FTIR) and constant heating rate experiments were performed to study the low temperature oxidation of coal treated by an ionic liquid,1-allyl-3-methylimidazolium chloride.The ine...Fourier transform infrared spectroscopy(FTIR) and constant heating rate experiments were performed to study the low temperature oxidation of coal treated by an ionic liquid,1-allyl-3-methylimidazolium chloride.The inerting effect of the ionic liquid toward the low temperature oxidation process is discussed.The results show that:(1) The hydroxyl content associated with hydrogen bonds,the aliphatic methyl content,the methylene group content,and the ether oxygen bond content are reduced in the treated coal.At the same time the content of aromatic C@C bonds is constant but these chemical bonds weaken and some substituted aromatic hydrocarbon content increases while other types decrease.This demonstrates that(AMIm)Cl dissolves and destroys the coal surface microstructure;(2) The oxygen consumption of the treated coal is less than what is seen in raw coal.The CO,CO 2,C 2 H 4,and C 2 H 6 content from the treated coal is reduced compared to the untreated coal;(3) The apparent activation energy for the oxidizing reaction is different in the treated and raw coals.Micro-structural changes and macroscopic gas production allow us to conclude that(AMIm)Cl can effectively inhibit low temperature oxidation of coal.展开更多
The pretreatment of rice straw is often used to enhance the hydrolysis. 1-allyl-3-methylimidazolium chloride （ [ AMIM ] C1） is a kind of low viscous, nontoxic and recyclable ionic liquid. It was used to treat rice s...The pretreatment of rice straw is often used to enhance the hydrolysis. 1-allyl-3-methylimidazolium chloride （ [ AMIM ] C1） is a kind of low viscous, nontoxic and recyclable ionic liquid. It was used to treat rice straw and improve the enzymatic hydrolysis of rice straw in this study. The factors influencing the pretreatment were as follows： the dosage of rice straw in [ AMIM ] Cl, crush mesh of rice straw, pretreatment temperature and time. After the pretreatment with a 3 % （the weight ratio of rice straw to ionic liquid） rice straw dosage in [AMIM]Cl at 110 ℃ for 1 h, the yield of reducing sugar of regenerated rice straw by 33 U/mL cellulase hydrolysis was 53.3 %, which was two times higher than that of un-treated rice straw （23.7 % ）. More researches regarding straw biorefinery to bacterial cellulose are being performed in the lab and prospective results will be published in near future.展开更多
Three isomorphic ionic bismuth(Ⅲ)halides were synthesized,utilizing 2,2’-bipyridyl-1,1’-dioxide(bp2do)as the organic ligand decorated on the halobismuthate(Ⅲ)moieties,namely,[Ammim][BiBr_(4)(bp2do)](1,Ammim=1-ally...Three isomorphic ionic bismuth(Ⅲ)halides were synthesized,utilizing 2,2’-bipyridyl-1,1’-dioxide(bp2do)as the organic ligand decorated on the halobismuthate(Ⅲ)moieties,namely,[Ammim][BiBr_(4)(bp2do)](1,Ammim=1-allyl-2,3-dimethylimidazolium),[Ammim][BiCl_(4)(bp2do)](2)and[Amim][BiCl_(4)(bp2do)](3,Amim=1-allyl-3-methylimidazolium).They all crystallize in the space group of Pca2_(1)with a similar supramolecular packing mode.However,the average adjacent Bi–Bi distances are slightly different,that is 1>2>3.Moreover,they possess different phosphorescence quantum yields(QYs)with 0.38%for 1,27.83%for 2 and 34.76%for 3.Note that the QY of 3 remains the highest for bp2do-based halobismuthate hybrids.Their phosphorescence originates from the organic ligand bp2do,in which an inorganic-to-organic charge transfer(IOCT)process exists,as confirmed by density functional theory(DFT)calculations.The three compounds possess X-ray scintillation properties.Eventually,a WLED could be fabricated by mixing commercial nitride red phosphor with cyan-emitting 3.This study provides a method for the synthesis of organic ligand based ionic bismuth halide hybrids with higher QYs,and enriches X-ray scintillation materials.展开更多
Amino-imidazolin-2-imines(HAmIm)are introduced as a new class of strong monoanionic N,N’-chelating ligands for Cu(I)complexes.The reaction of HAmIm with CuCl,followed by deprotonation to give AmIm−,affords the dinucl...Amino-imidazolin-2-imines(HAmIm)are introduced as a new class of strong monoanionic N,N’-chelating ligands for Cu(I)complexes.The reaction of HAmIm with CuCl,followed by deprotonation to give AmIm−,affords the dinuclear precursor[Cu2(μ-AmIm)2],which serves as a versatile platform for the synthesis of structurally diverse mononuclear Cu(I)complexes.Coordination with diimine ligands(phenanthroline or neocuproine)yields distorted tetrahedral[Cu(AmIm)(diimine)]species featuring a broad UV/vis absorption.In contrast,reaction with monodentate phosphines(L_(1)-L_(5))affords trigonal planar complexes[Cu(AmIm)(L)],which are non-emissive in solution,but exhibit pronounced emission in the solid state.All ten new complexes were structurally characterised by single-crystal X-ray diffraction,enabling a direct correlation between coordination geometry and photophysical properties.Photophysical studies and TDDFT calculations reveal fluorescence in the nanosecond-range originating from ligand-to-ligand and mixed metal-ligand-to-ligand charge-transfer transitions(LL’CT,mMLL’CT).The emission properties correlate with the nature of the phosphine ligand.In particular,complexes containing chalcogen-bridged phosphines(L_(4)and L_(5))display the highest intensities and lifetimes of up to≈29.2 and≈13.9 ns,respectively.Temperature-dependent time-resolved measurements confirm prompt fluorescence and exclude thermally activated delayed fluorescence(TADF),underscoring the intrinsic nature of the emission.These results highlight the modular potential of HAmIm ligands to access structurally diverse and photoactive Cu(I)complexes with tunable solid-state emission.展开更多
文摘Most previous studies on the market efficiency of cryptocurrencies consider time evolution but do not provide insights into the potential driving factors.This study addresses this limitation by examining the time-varying efficiency of the two largest cryptocurrencies,Bitcoin and Ethereum,and the factors that drive efficiency.It uses daily data from August 7,2016,to February 15,2023,the adjusted market inefficiency magnitude(AMIMs)measure,and quantile regression.The results show evidence of time variation in the levels of market(in)efficiency for Bitcoin and Ethereum.Interestingly,the quantile regressions indicate that global financial stress negatively affects the AMIMs measures across all quantiles.Notably,cryptocurrency liquidity positively and significantly affects AMIMs irrespective of the level of(in)efficiency,whereas the positive effect of money flow is significant when the markets of both cryptocurrencies are efficient.Finally,the COVID-19 pandemic positively and significantly affected cryptocurrency market inefficiencies across most quantiles.
基金support from the National Natural Science Foundation of China (No.51074159)The Graduate Scientific Research Innovation Programme of Jiangsu Province Ordinary University (No. CXZZ12_0957)
文摘Fourier transform infrared spectroscopy(FTIR) and constant heating rate experiments were performed to study the low temperature oxidation of coal treated by an ionic liquid,1-allyl-3-methylimidazolium chloride.The inerting effect of the ionic liquid toward the low temperature oxidation process is discussed.The results show that:(1) The hydroxyl content associated with hydrogen bonds,the aliphatic methyl content,the methylene group content,and the ether oxygen bond content are reduced in the treated coal.At the same time the content of aromatic C@C bonds is constant but these chemical bonds weaken and some substituted aromatic hydrocarbon content increases while other types decrease.This demonstrates that(AMIm)Cl dissolves and destroys the coal surface microstructure;(2) The oxygen consumption of the treated coal is less than what is seen in raw coal.The CO,CO 2,C 2 H 4,and C 2 H 6 content from the treated coal is reduced compared to the untreated coal;(3) The apparent activation energy for the oxidizing reaction is different in the treated and raw coals.Micro-structural changes and macroscopic gas production allow us to conclude that(AMIm)Cl can effectively inhibit low temperature oxidation of coal.
基金Science and Technology Commission of Shanghai Municipality (No.11230700600No.08520750200)+2 种基金Shanghai Municipal Education Commission (No.09ZZ68)the "111 " Project(No.B07024)the Fundamental Research Funds for the Central Universities and Key Laboratory of Science &Technology of Eco-Textile (Donghua University),Ministry of Education (No.Eco-op-2009-09)
文摘The pretreatment of rice straw is often used to enhance the hydrolysis. 1-allyl-3-methylimidazolium chloride （ [ AMIM ] C1） is a kind of low viscous, nontoxic and recyclable ionic liquid. It was used to treat rice straw and improve the enzymatic hydrolysis of rice straw in this study. The factors influencing the pretreatment were as follows： the dosage of rice straw in [ AMIM ] Cl, crush mesh of rice straw, pretreatment temperature and time. After the pretreatment with a 3 % （the weight ratio of rice straw to ionic liquid） rice straw dosage in [AMIM]Cl at 110 ℃ for 1 h, the yield of reducing sugar of regenerated rice straw by 33 U/mL cellulase hydrolysis was 53.3 %, which was two times higher than that of un-treated rice straw （23.7 % ）. More researches regarding straw biorefinery to bacterial cellulose are being performed in the lab and prospective results will be published in near future.
基金supported by the National Natural Science Foundation of China(No.21601181)the Natural Science Foundation of Fujian Province(No.2020J01118).
文摘Three isomorphic ionic bismuth(Ⅲ)halides were synthesized,utilizing 2,2’-bipyridyl-1,1’-dioxide(bp2do)as the organic ligand decorated on the halobismuthate(Ⅲ)moieties,namely,[Ammim][BiBr_(4)(bp2do)](1,Ammim=1-allyl-2,3-dimethylimidazolium),[Ammim][BiCl_(4)(bp2do)](2)and[Amim][BiCl_(4)(bp2do)](3,Amim=1-allyl-3-methylimidazolium).They all crystallize in the space group of Pca2_(1)with a similar supramolecular packing mode.However,the average adjacent Bi–Bi distances are slightly different,that is 1>2>3.Moreover,they possess different phosphorescence quantum yields(QYs)with 0.38%for 1,27.83%for 2 and 34.76%for 3.Note that the QY of 3 remains the highest for bp2do-based halobismuthate hybrids.Their phosphorescence originates from the organic ligand bp2do,in which an inorganic-to-organic charge transfer(IOCT)process exists,as confirmed by density functional theory(DFT)calculations.The three compounds possess X-ray scintillation properties.Eventually,a WLED could be fabricated by mixing commercial nitride red phosphor with cyan-emitting 3.This study provides a method for the synthesis of organic ligand based ionic bismuth halide hybrids with higher QYs,and enriches X-ray scintillation materials.
基金the German Federal Environmental Foundation for financial support(DBU,AZ:20024/029)Funded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)–Project Number 524554621.
文摘Amino-imidazolin-2-imines(HAmIm)are introduced as a new class of strong monoanionic N,N’-chelating ligands for Cu(I)complexes.The reaction of HAmIm with CuCl,followed by deprotonation to give AmIm−,affords the dinuclear precursor[Cu2(μ-AmIm)2],which serves as a versatile platform for the synthesis of structurally diverse mononuclear Cu(I)complexes.Coordination with diimine ligands(phenanthroline or neocuproine)yields distorted tetrahedral[Cu(AmIm)(diimine)]species featuring a broad UV/vis absorption.In contrast,reaction with monodentate phosphines(L_(1)-L_(5))affords trigonal planar complexes[Cu(AmIm)(L)],which are non-emissive in solution,but exhibit pronounced emission in the solid state.All ten new complexes were structurally characterised by single-crystal X-ray diffraction,enabling a direct correlation between coordination geometry and photophysical properties.Photophysical studies and TDDFT calculations reveal fluorescence in the nanosecond-range originating from ligand-to-ligand and mixed metal-ligand-to-ligand charge-transfer transitions(LL’CT,mMLL’CT).The emission properties correlate with the nature of the phosphine ligand.In particular,complexes containing chalcogen-bridged phosphines(L_(4)and L_(5))display the highest intensities and lifetimes of up to≈29.2 and≈13.9 ns,respectively.Temperature-dependent time-resolved measurements confirm prompt fluorescence and exclude thermally activated delayed fluorescence(TADF),underscoring the intrinsic nature of the emission.These results highlight the modular potential of HAmIm ligands to access structurally diverse and photoactive Cu(I)complexes with tunable solid-state emission.
