Understanding the physical mechanisms governing aggregation-induced-emission(AIE)and aggrega-tion-caused-quenching plays a vital role in developing functional AIE materials.In this work,tetraphenylethene(TPE,a classic...Understanding the physical mechanisms governing aggregation-induced-emission(AIE)and aggrega-tion-caused-quenching plays a vital role in developing functional AIE materials.In this work,tetraphenylethene(TPE,a classical AiEgen)and naphthalimide(NI,a popular fluorophore with ACQ characteristics)were connected through non-conjugated linkages and conjugated linkages.We showed that the nonconjugated-linkage of TPE to NI fragments leads to substantial PET in molecular aggregates and ACQ.In con trast,the conjugated conn ection between TPE and NI moieties results in the AIE phenomenon by suppressing twisted intramolecular charge transfer.This work provides an important guideline for the rational design of AIE materials.展开更多
Mercury ions are highly toxic and can accumulate along food chains in water,soil,crops and animals.Effective detection of mercury ions in various media is of great significance for maintaining the ecological environme...Mercury ions are highly toxic and can accumulate along food chains in water,soil,crops and animals.Effective detection of mercury ions in various media is of great significance for maintaining the ecological environment and protecting people's health.In this work,a mercury ions specific fluorescent probe was developed by a simple one-step reaction of commercial substrates of 4-chloro-7-nitro-2,1,3-benzoxadiazole and 1-(2-aminoethyl)-4-methylpiperazine.Investigation on sensing behavior showed that this probe had high sensitivity and selectivity towards mercury ions.Furthermore,this probe could be used as a tool to track the level of mercury ions in living system.In living cells,the probe with green emission emitted a bright red fluorescence when it was bound to mercury ions.In Arabidopsis thaliana,similar red emission could be detected from the root tip and stalk when A.thaliana was grown in culture medium containing mercury ions.The imaging in zebrafish showed that mercury ions were mainly concentrated in the stomach and head of zebrafish.Especially,this probe could be applied in quantitative analysis of mercury ions in tap water,green tea,sea shrimp and soil.This work provided a practical tool for the detection of mercury ions in living systems and quantitative analysis in real samples.展开更多
Benzothiadiazole(BTD) has been extensively used as a building block in optical materials. In this work, a class of π-conjugated BTD-based luminogens BTD-685, BTD-580, BTD-675 and BTD-565 were designed by varying dono...Benzothiadiazole(BTD) has been extensively used as a building block in optical materials. In this work, a class of π-conjugated BTD-based luminogens BTD-685, BTD-580, BTD-675 and BTD-565 were designed by varying donor units and facilely synthesized by Heck coupling reaction. It was found that their emission in solid state covered the regio from orange, red to near infrared fluorescence. Investigation on photo-physical property manifested that they had strong solvatochromic behavior except symmetric 2-vinylpyridine substituted BTD-565. Crystal X-ray diffraction analysis revealed that they involved in multi weak intermolecular interactions. And loose molecular packing implied that they can be easily rearranged under external force stimuli.Indeed, all compounds showed reversible mechanically-responsive behavior in solid state. Interestingly, the vinylpyridinecontaining BTD-565 exhibited hypochromatic mechanochromic behavior, whereas others showed bathochromic mechanochromism behavior. It was worth mentioning that BTD-675 had self-recovery behavior after grinding. The powder X-ray diffraction study showed that these chromic processes may be mainly attributed to the reversible morphological changes between crystalline and amorphous phase upon grinding or fuming. These observations suggested that the vinyl-functionalized benzothiadiazoles can be considered as a type of excellent candidates in mechanically-responsive chromic materials.展开更多
financial services:for example,GPS and Bluetooth inspire location-based services,and search and web technologies motivate online shopping,reviews,and payments.These business services have become more connected than ev...financial services:for example,GPS and Bluetooth inspire location-based services,and search and web technologies motivate online shopping,reviews,and payments.These business services have become more connected than ever,and as a result,financial frauds have become a significant challenge.Therefore,combating financial risks in the big data era requires breaking the borders of traditional data,algorithms,and systems.An increasing number of studies have addressed these challenges and proposed new methods for risk detection,assessment,and forecasting.As a key contribution,we categorize these works in a rational framework:first,we identify the data that can be used to identify risks.We then discuss how big data can be combined with the emerging tools to effectively learn or analyze financial risk.Finally,we highlight the effectiveness of these methods in real-world applications.Furthermore,we stress on the importance of utilizing multi-channel information,graphs,and networks of long-range dependence for the effective identification of financial risks.We conclude our survey with a discussion on the new challenges faced by the financial sector,namely,deep fake technology,adversaries,causal and interpretable inference,privacy protection,and microsimulations.展开更多
Photophysical properties of organic and organometallic luminophors are closely related with their molecular packings, enabling the exploitation of stimuli-responsive functional luminescent molecules.Mechanochromic mol...Photophysical properties of organic and organometallic luminophors are closely related with their molecular packings, enabling the exploitation of stimuli-responsive functional luminescent molecules.Mechanochromic molecules, which can change their luminescence characteristics after mechanical stimulus, have received an increasing interest due to their promising applications in multifunctional sensors and molecular switches. During the past two decades, the development of gold(Ⅰ) chemistry has been attracting the attention of plenty of researchers. Indeed, a variety of gold(I) complexes with fascinating photophysical behaviors have been discovered. This review focuses on the research progress in the different types of mechanoluminochromic gold(Ⅰ) complexes, including mono-, bi-and multi-nuclear gold(Ⅰ)systems. Their interesting luminescence behaviors of these gold(Ⅰ)-containing luminogens upon mechanical stimulus and the proposed mechanisms of their observed mechanochromic luminescence are summarized systematacially. Moreover, this review will put forward an outlook about the possible opportunities and challenges in this significative scientific field.展开更多
The detection of cations has attracted considerable interest because of their importance in various physiological processes. In this study, compound 1 bearing sulfonamidc and morpholine functionalities was synthesized...The detection of cations has attracted considerable interest because of their importance in various physiological processes. In this study, compound 1 bearing sulfonamidc and morpholine functionalities was synthesized. Its structure was well characterized by NMR spectroscopy and mass spectrometry. UV/vis absorption spectra and fluorescence spectra indicated that it displayed high sensitivity and selectivity for Cu^2＋ and Ag^＋ by switching solvent media. It means that： （1） it showed selective response to Cu2＋ in acetonitrile, （2） whereas it exhibited high selectivity for Ag^＋ in water. The density functional theory calculations were used to clearly explain the different recognition behaviors in different solvent media. This research suggests that compound 1 bearing sulfonamide and morpholine functionalities could act as a multiftmctional chemosensor for monitoring multiple cations by changing solvent media and provides an alternative approach to design novel dual cations chemosensors.展开更多
The control of PM emission is a rather complicated problem to be solved both for diesel engine and GDI engines.There are vast factors affecting PM emission,the fuel,A/F,combustion temperature and so on.But undoubtedly...The control of PM emission is a rather complicated problem to be solved both for diesel engine and GDI engines.There are vast factors affecting PM emission,the fuel,A/F,combustion temperature and so on.But undoubtedly,most efforts are paid to exhaust aftertreatment,rather than the control of generation.This paper is to investigate the effect of dimethyl ether(DME,CH3OCH3)on soot generation in flame.Therefore,a laser induced incandescence(LII)measurement system for soot volume concentration measurements in flame is used.Two DME gaseous mixtures were prepared with equivalence ratios 1 and 2.To highlight its effect on soot formation,acetylene known as the precursor of soot,is added in different ratios.Similarly,CO2 is mixed to simulate exhaust gas recycling(EGR)effect in engines.The experimental results indicate that the fuel property and A/F ratio are the dominating factors for the generation of soot during combustion.The combustion of DME doesn't emit soot obviously even under rich mixture condition.When burning the mixture of DME and acetylene(C2H2)in different proportion,there is barely soot emission at equivalence ratio of 1.The soot emission increases as the proportion of C2H2 increases at equivalence ratio 2,and the DME addition reduces the soot emission of C2H2 flame.CO2 dilution doesn't lead to the increase of soot when burning DME at equivalence 1 and 2.Soot emission is lower when the mixture of DME and acetylene is diluted by CO2,though soot volume concentration increases slightly as the proportion of C2H2 increases.The kinetic analysis indicates that the combustion of DME does not produce the precursor of soot.Under fuel-rich combustion conditions,C2H2 reacts with H radical to form C2H3,which leads to soot.When DME is added,it competes for H radical,which reduces the formation of C2H3 and thus reduces soot formation.The research carried out in this paper indicates that DME fuel has obviously power to reduce soot formation during combustion,no matter whether it is diluted by CO2 or mixed with soot precursor substance C2 H2.展开更多
基金financial support from the National Natural Science Foundation of China (Nos.21676113,21772054)Distinguished Young Scholar Program of Hubei Province (No. 2018CFA079)+5 种基金the 111 Project B17019the Scholar Support Program of CCNU (No.0900-31101090002)the Excellent Doctoral Dissertation Cultivation Grant of CCNU from the colleges’ basic research and operation grant (MOE,No.2019YBZZ029)supported by Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules (No. KLSAOFM2012),Hubei University,Chinasupported by excellent doctorial dissertation cultivation grant of CCNU from the colleges’ basic research and operation of MOE (No.2019YBZZ029)A*STAR under its Advanced Manufacturing and Engineering Program (No.A2083c0051)
文摘Understanding the physical mechanisms governing aggregation-induced-emission(AIE)and aggrega-tion-caused-quenching plays a vital role in developing functional AIE materials.In this work,tetraphenylethene(TPE,a classical AiEgen)and naphthalimide(NI,a popular fluorophore with ACQ characteristics)were connected through non-conjugated linkages and conjugated linkages.We showed that the nonconjugated-linkage of TPE to NI fragments leads to substantial PET in molecular aggregates and ACQ.In con trast,the conjugated conn ection between TPE and NI moieties results in the AIE phenomenon by suppressing twisted intramolecular charge transfer.This work provides an important guideline for the rational design of AIE materials.
文摘Mercury ions are highly toxic and can accumulate along food chains in water,soil,crops and animals.Effective detection of mercury ions in various media is of great significance for maintaining the ecological environment and protecting people's health.In this work,a mercury ions specific fluorescent probe was developed by a simple one-step reaction of commercial substrates of 4-chloro-7-nitro-2,1,3-benzoxadiazole and 1-(2-aminoethyl)-4-methylpiperazine.Investigation on sensing behavior showed that this probe had high sensitivity and selectivity towards mercury ions.Furthermore,this probe could be used as a tool to track the level of mercury ions in living system.In living cells,the probe with green emission emitted a bright red fluorescence when it was bound to mercury ions.In Arabidopsis thaliana,similar red emission could be detected from the root tip and stalk when A.thaliana was grown in culture medium containing mercury ions.The imaging in zebrafish showed that mercury ions were mainly concentrated in the stomach and head of zebrafish.Especially,this probe could be applied in quantitative analysis of mercury ions in tap water,green tea,sea shrimp and soil.This work provided a practical tool for the detection of mercury ions in living systems and quantitative analysis in real samples.
基金supported by the National Natural Science Foundation of China (21676113, 21402057, 21772054, 21472059, 21702079)Distinguished Young Scholar of Hubei Province (2018CFA079)+6 种基金Youth Chen-Guang Project of Wuhan (2016070204010098)the 111 Project (B17019)the Ministry-Province Jointly Constructed Base for State Key Lab-Shenzhen Key Laboratory of Chemical Biology (Shenzhen)the State Key Laboratory of Materials-Oriented Chemical Engineering (KL17-10)Open Project Fund of Key Laboratory of Natural Resources of Changbai Mountain & Functional Molecules (Yanbian University, NRFM201701)Ministry of Education, the foundation of Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, Jiangnan University (JDSJ2017-07)self-determined research funds of CCNU from the colleges’ basic research and operation of MOE (CCNU18TS012)
文摘Benzothiadiazole(BTD) has been extensively used as a building block in optical materials. In this work, a class of π-conjugated BTD-based luminogens BTD-685, BTD-580, BTD-675 and BTD-565 were designed by varying donor units and facilely synthesized by Heck coupling reaction. It was found that their emission in solid state covered the regio from orange, red to near infrared fluorescence. Investigation on photo-physical property manifested that they had strong solvatochromic behavior except symmetric 2-vinylpyridine substituted BTD-565. Crystal X-ray diffraction analysis revealed that they involved in multi weak intermolecular interactions. And loose molecular packing implied that they can be easily rearranged under external force stimuli.Indeed, all compounds showed reversible mechanically-responsive behavior in solid state. Interestingly, the vinylpyridinecontaining BTD-565 exhibited hypochromatic mechanochromic behavior, whereas others showed bathochromic mechanochromism behavior. It was worth mentioning that BTD-675 had self-recovery behavior after grinding. The powder X-ray diffraction study showed that these chromic processes may be mainly attributed to the reversible morphological changes between crystalline and amorphous phase upon grinding or fuming. These observations suggested that the vinyl-functionalized benzothiadiazoles can be considered as a type of excellent candidates in mechanically-responsive chromic materials.
基金supported by the National Natural Science Foundation of China under Grant Nos.91746301,61772498,61802370,and 61902380.
文摘financial services:for example,GPS and Bluetooth inspire location-based services,and search and web technologies motivate online shopping,reviews,and payments.These business services have become more connected than ever,and as a result,financial frauds have become a significant challenge.Therefore,combating financial risks in the big data era requires breaking the borders of traditional data,algorithms,and systems.An increasing number of studies have addressed these challenges and proposed new methods for risk detection,assessment,and forecasting.As a key contribution,we categorize these works in a rational framework:first,we identify the data that can be used to identify risks.We then discuss how big data can be combined with the emerging tools to effectively learn or analyze financial risk.Finally,we highlight the effectiveness of these methods in real-world applications.Furthermore,we stress on the importance of utilizing multi-channel information,graphs,and networks of long-range dependence for the effective identification of financial risks.We conclude our survey with a discussion on the new challenges faced by the financial sector,namely,deep fake technology,adversaries,causal and interpretable inference,privacy protection,and microsimulations.
基金financial support from the National Natural Science Foundation of China (Nos. 22061018, 21702079 and 21772054)the startup funding from South-Central University for Nationalities (No. YZZ19005)。
文摘Photophysical properties of organic and organometallic luminophors are closely related with their molecular packings, enabling the exploitation of stimuli-responsive functional luminescent molecules.Mechanochromic molecules, which can change their luminescence characteristics after mechanical stimulus, have received an increasing interest due to their promising applications in multifunctional sensors and molecular switches. During the past two decades, the development of gold(Ⅰ) chemistry has been attracting the attention of plenty of researchers. Indeed, a variety of gold(I) complexes with fascinating photophysical behaviors have been discovered. This review focuses on the research progress in the different types of mechanoluminochromic gold(Ⅰ) complexes, including mono-, bi-and multi-nuclear gold(Ⅰ)systems. Their interesting luminescence behaviors of these gold(Ⅰ)-containing luminogens upon mechanical stimulus and the proposed mechanisms of their observed mechanochromic luminescence are summarized systematacially. Moreover, this review will put forward an outlook about the possible opportunities and challenges in this significative scientific field.
基金This work was supported by National Natural Science Foundation of China （Nos. 20931006, 21072070, 21272088 and 21571110）, the Program for Academic Leader in Wuhan Municipality （No. 201271130441）, the Natural Science Foundation of Ningbo City （No. 2016A610051） and financially supported by research funds of NBU （No. ZX2015000586）.
文摘The detection of cations has attracted considerable interest because of their importance in various physiological processes. In this study, compound 1 bearing sulfonamidc and morpholine functionalities was synthesized. Its structure was well characterized by NMR spectroscopy and mass spectrometry. UV/vis absorption spectra and fluorescence spectra indicated that it displayed high sensitivity and selectivity for Cu^2＋ and Ag^＋ by switching solvent media. It means that： （1） it showed selective response to Cu2＋ in acetonitrile, （2） whereas it exhibited high selectivity for Ag^＋ in water. The density functional theory calculations were used to clearly explain the different recognition behaviors in different solvent media. This research suggests that compound 1 bearing sulfonamide and morpholine functionalities could act as a multiftmctional chemosensor for monitoring multiple cations by changing solvent media and provides an alternative approach to design novel dual cations chemosensors.
基金the financial support of Science and Technology Department of Shaanxi Province(2018ZDCXL-GY-05-06 and 2019ZDLGY15-07)。
文摘The control of PM emission is a rather complicated problem to be solved both for diesel engine and GDI engines.There are vast factors affecting PM emission,the fuel,A/F,combustion temperature and so on.But undoubtedly,most efforts are paid to exhaust aftertreatment,rather than the control of generation.This paper is to investigate the effect of dimethyl ether(DME,CH3OCH3)on soot generation in flame.Therefore,a laser induced incandescence(LII)measurement system for soot volume concentration measurements in flame is used.Two DME gaseous mixtures were prepared with equivalence ratios 1 and 2.To highlight its effect on soot formation,acetylene known as the precursor of soot,is added in different ratios.Similarly,CO2 is mixed to simulate exhaust gas recycling(EGR)effect in engines.The experimental results indicate that the fuel property and A/F ratio are the dominating factors for the generation of soot during combustion.The combustion of DME doesn't emit soot obviously even under rich mixture condition.When burning the mixture of DME and acetylene(C2H2)in different proportion,there is barely soot emission at equivalence ratio of 1.The soot emission increases as the proportion of C2H2 increases at equivalence ratio 2,and the DME addition reduces the soot emission of C2H2 flame.CO2 dilution doesn't lead to the increase of soot when burning DME at equivalence 1 and 2.Soot emission is lower when the mixture of DME and acetylene is diluted by CO2,though soot volume concentration increases slightly as the proportion of C2H2 increases.The kinetic analysis indicates that the combustion of DME does not produce the precursor of soot.Under fuel-rich combustion conditions,C2H2 reacts with H radical to form C2H3,which leads to soot.When DME is added,it competes for H radical,which reduces the formation of C2H3 and thus reduces soot formation.The research carried out in this paper indicates that DME fuel has obviously power to reduce soot formation during combustion,no matter whether it is diluted by CO2 or mixed with soot precursor substance C2 H2.
