Hexagonal boron nitride nanosheets(BNNSs)exhibit remarkable thermal and dielectric properties.However,their self-assembly and alignment in macroscopic forms remain challenging due to the chemical inertness of boron ni...Hexagonal boron nitride nanosheets(BNNSs)exhibit remarkable thermal and dielectric properties.However,their self-assembly and alignment in macroscopic forms remain challenging due to the chemical inertness of boron nitride,thereby limiting their performance in applications such as thermal management.In this study,we present a coaxial wet spinning approach for the fabrication of BNNSs/polymer composite fibers with high nanosheet orientation.The composite fibers were prepared using a superacid-based solvent system and showed a layered structure comprising an aramid core and an aramid/BNNSs sheath.Notably,the coaxial fibers exhibited significantly higher BNNSs alignment compared to uniaxial aramid/BNNSs fibers,primarily due to the additional compressive forces exerted at the core-sheath interface during the hot drawing process.With a BNNSs loading of 60 wt%,the resulting coaxial fibers showed exceptional properties,including an ultrahigh Herman orientation parameter of 0.81,thermal conductivity of 17.2 W m^(-1)K^(-1),and tensile strength of 192.5 MPa.These results surpassed those of uniaxial fibers and previously reported BNNSs composite fibers,making them highly suitable for applications such as wearable thermal management textiles.Our findings present a promising strategy for fabricating high-performance composite fibers based on BNNSs.展开更多
The perception module of advanced driver assistance systems plays a vital role.Perception schemes often use a single sensor for data processing and environmental perception or adopt the information processing results ...The perception module of advanced driver assistance systems plays a vital role.Perception schemes often use a single sensor for data processing and environmental perception or adopt the information processing results of various sensors for the fusion of the detection layer.This paper proposes a multi-scale and multi-sensor data fusion strategy in the front end of perception and accomplishes a multi-sensor function disparity map generation scheme.A binocular stereo vision sensor composed of two cameras and a light deterction and ranging(LiDAR)sensor is used to jointly perceive the environment,and a multi-scale fusion scheme is employed to improve the accuracy of the disparity map.This solution not only has the advantages of dense perception of binocular stereo vision sensors but also considers the perception accuracy of LiDAR sensors.Experiments demonstrate that the multi-scale multi-sensor scheme proposed in this paper significantly improves disparity map estimation.展开更多
Automatic text summarization(ATS)plays a significant role in Natural Language Processing(NLP).Abstractive summarization produces summaries by identifying and compressing the most important information in a document.Ho...Automatic text summarization(ATS)plays a significant role in Natural Language Processing(NLP).Abstractive summarization produces summaries by identifying and compressing the most important information in a document.However,there are only relatively several comprehensively evaluated abstractive summarization models that work well for specific types of reports due to their unstructured and oral language text characteristics.In particular,Chinese complaint reports,generated by urban complainers and collected by government employees,describe existing resident problems in daily life.Meanwhile,the reflected problems are required to respond speedily.Therefore,automatic summarization tasks for these reports have been developed.However,similar to traditional summarization models,the generated summaries still exist problems of informativeness and conciseness.To address these issues and generate suitably informative and less redundant summaries,a topic-based abstractive summarization method is proposed to obtain global and local features.Additionally,a heterogeneous graph of the original document is constructed using word-level and topic-level features.Experiments and analyses on public review datasets(Yelp and Amazon)and our constructed dataset(Chinese complaint reports)show that the proposed framework effectively improves the performance of the abstractive summarization model for Chinese complaint reports.展开更多
Existing signal control systems for urban traffic are usually based on traffic flow data from fixed location detectors.Because of rapid advances in emerging vehicular communication,connected vehicle(CV)-based signal c...Existing signal control systems for urban traffic are usually based on traffic flow data from fixed location detectors.Because of rapid advances in emerging vehicular communication,connected vehicle(CV)-based signal control demonstrates significant improvements over existing conventional signal control systems.Though various CV-based signal control systems have been investigated in the past decades,these approaches still have many issues and drawbacks to overcome.We summarize typical components and structures of these existing CV-based urban traffic signal control systems and digest several important issues from the summarized vital concepts.Last,future research directions are discussed with some suggestions.We hope this survey can facilitate the connected and automated vehicle and transportation research community to efficiently approach next-generation urban traffic signal control methods and systems.展开更多
Using catalytic oxidative absorption for H_2S removal is of great interest due to its distinct advantages. However,traditional scrubbing process faces a great limitation in the confined space. Therefore, there is an u...Using catalytic oxidative absorption for H_2S removal is of great interest due to its distinct advantages. However,traditional scrubbing process faces a great limitation in the confined space. Therefore, there is an urgent demand to develop high-efficiency process intensification technology for such a system. In this article, H_2S absorption experimental research was conducted in a rotating packed bed(RPB) reactor with ferric chelate absorbent and a mixture of N_2 and H_2S, which was used to simulate natural gas. The effects of absorbent p H value, gas–liquid ratio, gravity level of RPB, absorption temperature and character of the packing on the desulfurization efficiency were investigated. The results showed that H_2S removal efficiency could reach above 99.6% under the most of the experimental condition and above 99.9% under the optimal condition. A long-time continuous experiment was conducted to investigate the stability of the whole process combining absorption and regeneration. The result showed that the process could well realize simultaneous desulfurization and absorbent regeneration, and the H_2S removal efficiency kept relatively stable in the whole duration of 72 h. It can be clearly seen that high gravity technology desulfurization process, which is simple, high-efficiency, and space intensive, has a good prospect for industrial application of H_2S removal in confined space.展开更多
Automotive collision avoidance technology can effectively avoid the accidents caused by dangerous traffic conditions or driver's manipulation errors.Moreover,it can promote the development of autonomous driving fo...Automotive collision avoidance technology can effectively avoid the accidents caused by dangerous traffic conditions or driver's manipulation errors.Moreover,it can promote the development of autonomous driving for intelligent vehicle in intelligent transportation.We present a collision avoidance system,which is composed of an evasive trajectory planner and a path following controller.Considering the stability of the vehicle in the conflict-free process,the evasive trajectory planner is designed by polynomial parametric method and optimized by genetic algorithm.The path following controller is proposed to make the car drive along the designed path by controlling the vehicle's lateral movement.Simulation results show that the vehicle with the proposed controller has good stability in the collision process,and it can ensure the vehicle driving in accordance with the planned trajectory at different speeds.The research results can provide a certain basis for the research and development of automotive collision avoidance technology.展开更多
The influences of plastic deformation, aging treatment, and alloying elements on the texture of Cu-Cr-Zr alloys were explored. The texture component and intensity of Cu-Cr-Zr alloys under various working conditions af...The influences of plastic deformation, aging treatment, and alloying elements on the texture of Cu-Cr-Zr alloys were explored. The texture component and intensity of Cu-Cr-Zr alloys under various working conditions after aging treatment were characterized using the orientation distributing function (ODF). The influence of Zr content on the texture of Cu-Cr-Zr alloys was also analyzed. The reduction pass and deformation level were primary factors influencing the texture. Rolling texture appeared in a rolled plate and the fibrous textures of {111} and {001} were detected after 80% deformation. Fibrous texture with a main constituent of {111} improved the tensile strength of the alloy wire. The texture contents of {110}<331> and {110}<112> were predominated, whereas, those of {113}<332> and {112}<111> were in the minority in the Cu-Cr-Zr alloy with a higher Zr content (>0.5wt%). However, in the samples with a lower Zr content (<0.1wt%), the texture contents of {113}<332>, {112}<111>, and {111}<110> were in the majority.展开更多
All-solid-state sodium-ion battery is regarded as the next generation battery to replace the current commercial lithium-ion battery, with the advantages of abundant sodium resources, low price and high-level safety. A...All-solid-state sodium-ion battery is regarded as the next generation battery to replace the current commercial lithium-ion battery, with the advantages of abundant sodium resources, low price and high-level safety. As one critical component in sodium-ion battery, solid-state electrolyte should possess superior operational safety and design simplicity, yet reasonable high room-temperature ionic conductivity. This paper gives a comprehensive review on the recent progress in solid-state electrolyte materials for sodium-ion battery, including inorganic ceramic/glass-ceramic, organic polymer and ceramic-polymer composite electrolytes, and also provides a comparison of the ionic conductivity in various solid-state electrolyte materials. The development of solid-state electrolytes suggests a bright future direction: all solid-state sodium-ion battery could be fully used to power all electric road vehicles, portable electronic devices and large-scale grid support.展开更多
Here,a plasmon-enhanced random laser was achieved by incorporating gold nanostars(NS) into disordered polymer and Cd Se/Zn S quantum dots(QDs) gain medium films,in which the surface plasmon resonance of gold NS can gr...Here,a plasmon-enhanced random laser was achieved by incorporating gold nanostars(NS) into disordered polymer and Cd Se/Zn S quantum dots(QDs) gain medium films,in which the surface plasmon resonance of gold NS can greatly enhance the scattering cross section and bring a large gain volume.The random distribution of gold NS in the gain medium film formed a laser-mode resonator.Under a single-pulse pumping,the scattering center of gold NS-based random laser exhibits enhanced performance of a lasing threshold of 0.8 m J/cm^2 and a full width as narrow as 6 nm at half maximum.By utilizing the local enhancement characteristic of the electric field at the sharp apexes of the gold NS,the emission intensity of the random laser was increased.In addition,the gold NS showed higher thermal stability than the silver nanoparticles,withstanding high temperature heating up to 200?C.The results of metal nanostructures with enriched hot spots and excellent temperature stability have tremendous potential applications in the fields of biological identification,medical diagnostics,lighting,and display devices.展开更多
Developments in the contents of different typical inclusions in 3104 alloy melt were described during heating and holding processing. The settling process of inclusion particles was investigated by measuring the conte...Developments in the contents of different typical inclusions in 3104 alloy melt were described during heating and holding processing. The settling process of inclusion particles was investigated by measuring the contents of inclusions in the surface, center, and bottom layers of the molten metal. In the results, main inclusions observed and determined by Prefil and PoD FA methods are MgO, Al_2O_3, spinel(MgAl_2O_4), and TiB_2 particles or thin films. It is found that some small particles of Al_2O_3 and MgO are transformed into spinel particles, and the formation rate increases as the temperature and the holding period of melt increase. The content of inclusions increases from 3.37 mm^2×kg^(-1) to 7.54 mm^2×kg^(-1) and then decreases to 3.08 mm^2×kg^(-1) after holding for 90 min. This is attributed to a settling phenomenon and a significant increase in settling velocity after holding for 60 min. The content of inclusion particles decreases by means of settlement and flotation in liquid aluminum with an increase in holding time. The theoretical analysis and experiment results are in essential agreement with those from industrial production.展开更多
Growing evidence has shown that exposure to low ambient temperature poses a huge challenge to human health globally.Actually,cold stress is closely associated with a higher incidence of cardiovascular morbidity and mo...Growing evidence has shown that exposure to low ambient temperature poses a huge challenge to human health globally.Actually,cold stress is closely associated with a higher incidence of cardiovascular morbidity and mortality in winter or in cold regions.Cellular and molecular mechanisms underlying cardiovascular complications in response to cold exposure have yet to be fully clarified.Considering that cold exposure is an important risk of cardiovascular complications,it is necessary to clarify the molecular mechanism of cold stress-induced cardiovascular diseases and to develop effective intervention strategies.Hydrogen sulfide(H2S),nitric oxide(NO),and carbon monoxide(CO)are well-known gasotransmitters that are endogenously produced in many biological systems.Accumulating studies have demonstrated that these gasotransmitters play a critical role in a wide spectrum of physiological and/or pathophysiological processes by regulating numerous signaling pathways.These gas signal molecules are emerging as important players in cardiovascular homeostasis,and disruption of these gasotransmitters is critically implicated in cardiovascular anomalies,such as hypertension,atherosclerosis,myocardial ischemia,heart failure,and stroke.Also,evidence is emerging that H2S,NO,and CO may be involved in the pathologies of cold stress-induced cardiovascular ailments.In this review,we aim to highlight and discuss the recent advances towards the development of gasotransmitters-based therapeutics for cold stress-related cardiovascular pathogenesis.We believe that the effects of H2S,NO,and CO on cardiovascular regulation under cold environment will attract tremendous interest in the near future as they serve as novel regulators of cardiovascular biology in cold environment.展开更多
Petroleum sulfonate is one of the most important surfactants used in surfactant flooding for enhanced oil recovery, which is mainly obtained by treating high-boiling petroleum fractions in a stirred tank reactor(STR) ...Petroleum sulfonate is one of the most important surfactants used in surfactant flooding for enhanced oil recovery, which is mainly obtained by treating high-boiling petroleum fractions in a stirred tank reactor(STR) or in a fallingfilm reactor(FFR). The synthesis of petroleum sulfonate with ultra-low interfacial tension from viscous petroleum fractions was carried out in a rotating packed bed(RPB) reactor using dilute liquid sulfur trioxide as the sulfonating agent in this study. The effects of various experimental conditions on components content and oil-water interfacial tension(IFT) were investigated. Under the optimum conditions, the active matter content could reach up to 50.3% and the IFT could be equal to 4.7×10-3 m N/m. Compared with the traditional reactor, the active matter content is by 14.12% higher in the RPB as compared to that obtained in the STR. The uneven change of the test oil droplets during the IFT measurement was also discussed. The increase of heavy components content not only can eliminate the contraction phenomenon, but also can reduce the IFT to a minimum. This can be conducive to explaining the reason for producing IFT and the preparation of proper formulations for practical application.展开更多
Metal-organic frameworks(MOFs)have been extensively used for gas sorption,storage and separation owing to ultrahigh porosity,exceptional thermal stability,and wide structural diversity.However,when it comes to ultra-l...Metal-organic frameworks(MOFs)have been extensively used for gas sorption,storage and separation owing to ultrahigh porosity,exceptional thermal stability,and wide structural diversity.However,when it comes to ultra-low concentration gas detection,technical bottlenecks of MOFs appear due to the poor adsorption capacity at ppm-/ppblevel concentration and the limited sensitivity for signal transduction.Here,we present hybrid MOF-polymer physi-chemisorption mechanisms integrated with infrared(IR)nanoantennas for highly selective and ultrasensitive CO_(2) detection.To improve the adsorption capacity for trace amounts of gas molecules,MOFs are decorated with amino groups to introduce the chemisorption while maintaining the structural integrity for physisorption.Additionally,leveraging all major optimization methods,a multi-hotspot strategy is proposed to improve the sensitivity of nanoantennas by enhancing the near field and engineering the radiative and absorptive loss.As a benefit,we demonstrate the competitive advantages of our strategy against the state-of-the-art miniaturized IR CO_(2) sensors,including low detection limit,high sensitivity(0.18%/ppm),excellent reversibility(variation within 2%),and high selectivity(against C_(2)H_(5)OH,CH_(3)OH,N_(2)).This work provides valuable insights into the integration of advanced porous materials and nanophotonic devices,which can be further adopted in ultra-low concentration gas monitoring in industry and environmental applications.展开更多
Nitrile compounds are a class of high-value chemicals and versatile intermediates which can easily be transformed into a variety of useful products bearing functional groups such as carboxyl, carbamoyl, aminomethyl, k...Nitrile compounds are a class of high-value chemicals and versatile intermediates which can easily be transformed into a variety of useful products bearing functional groups such as carboxyl, carbamoyl, aminomethyl, ketyl and heterocyclic derivatives. Various thermal catalytic cyanation procedures have been devised and scaled up industrially while developing alternative methods are actively pursued. The access to these classes of molecules electrochemically offers greener alternatives to their preparation. The development of electrochemical synthesis of cyano-containing compounds under mild conditions with low energy consumption will imminently become indispensable approaches for industrial production of nitriles. The electrochemical cyanation presents many challenges from the toxicity of cyanide to the development of catalysts and the design of electrochemical cells. Electrochemical cyanation reaction offers promise to conveniently accessing nitriles but still requires efficient electro-catalysts, safe protocols and scale up considerations. This review discusses recent progress in the field of electrochemical synthesis of nitrile compounds placing emphasis on electro-synthetic and electro-catalytic mechanism aspects while making reference to original works to highlight the progress in this area.展开更多
Pore structure of hard carbon has a fundamental influence on the electrochemical properties in sodium-ion batteries(SIBs).Ultra-micropores(<0.5 nm)of hard carbon can function as ionic sieves to reduce the diffusion...Pore structure of hard carbon has a fundamental influence on the electrochemical properties in sodium-ion batteries(SIBs).Ultra-micropores(<0.5 nm)of hard carbon can function as ionic sieves to reduce the diffusion of slovated Na+but allow the entrance of naked Na^(+) into the pores,which can reduce the interficial contact between the electrolyte and the inner pores without sacrificing the fast diffusion kinetics.Herein,a molten diffusion-carbonization method is proposed to transform the micropores(>1 nm)inside carbon into ultra-micropores(<0.5 nm).Consequently,the designed carbon anode displays an enhanced capacity of 346 mAh g^(−1) at 30 mA g^(−1) with a high ICE value of~80.6%and most of the capacity(~90%)is below 1 V.Moreover,the high-loading electrode(~19 mg cm^(−2))exhibits a good temperature endurance with a high areal capacity of 6.14 mAh cm^(−2) at 25℃ and 5.32 mAh cm^(−2) at −20℃.Based on the in situ X-ray diffraction and ex situ solid-state nuclear magnetic resonance results,the designed ultra-micropores provide the extra Na+storage sites,which mainly contributes to the enhanced capacity.This proposed strategy shows a good potential for the development of high-performance SIBs.展开更多
Carbonaceous materials are the most promising candidates as the anode for sodium-ion batteries (SIBs), however, they still suffer from low electric conductivity and sluggish sodium ion (Na+) reaction kinetics. Appropr...Carbonaceous materials are the most promising candidates as the anode for sodium-ion batteries (SIBs), however, they still suffer from low electric conductivity and sluggish sodium ion (Na+) reaction kinetics. Appropriate composition modulation using heteroatoms doping and structure optimization is highly desired. A basic empirical understanding of the structure-capacity relationship is also urgent in tackling the above problems. Herein, multi-functional nitrogen (N) doped carbon micro-rods with enlarged interlayer spacing are synthesized and investigated as the anode in SIBs, showing an ultra-stable capacity of 161.5 mAh g^(−1) at 2 A g^(−1) for over 5000 cycles. Experimental investigations and first-principle calculations indicate that the enlarged interlayer spacing can facilitate Na+ intercalation and N doping can guarantee the high electric conductivity and favorable electrochemical active sites. Additionally, pyridinic N is theoretically proved to be more effective to enhance Na+ adsorption than pyrrolic N due to the lower adsorption energy and stronger binding energy with Na+. Full SIBs show a high capacity and cyclability, making the biomass-derived carbon micro-rods to be a promising anode for practical SIBs applications.展开更多
There is a lack of reported studies on how the long duration wearing of N95 respirators or surgical facemasks will affect the upper airway functions. Considering the frequency of mask wearing especially in hospitals a...There is a lack of reported studies on how the long duration wearing of N95 respirators or surgical facemasks will affect the upper airway functions. Considering the frequency of mask wearing especially in hospitals and during an outbreak of influenza, it is essential to have such data documented. Therefore, the current study is to establish the effect of long duration wearing of N95 and surgical facemasks on upper airway functions. 47 staffs of National University Hospital Singapore in 2013 were recruited. Each of the volunteers wore both N95 respirator and surgical facemask for 3 hours on two different days. During the period of mask wearing, relative airflow rates were recorded. Smell function test was carried out before and after mask wearing. The results show that no significant change of smell test score was found after removal of both the two types of masks. With N95 respirator, more air was breathed into the upper airways compared to surgical facemask.展开更多
Spinel cathode is one of promising candidatesfor high-performance lithium-ion batteries due toits high voltage and hence high energy.This kind ofmaterial has excellent rate performance with 3D lith-ium diffusion pathw...Spinel cathode is one of promising candidatesfor high-performance lithium-ion batteries due toits high voltage and hence high energy.This kind ofmaterial has excellent rate performance with 3D lith-ium diffusion pathway and it is inexpensive,stableand environmentally friendly.AlthoughLi Mn1.5Ni0.5O4suffers from its limited capacity展开更多
Achieving low charge overpotentials represents one of the most critical challenges for pursuing highperformance lithium-oxygen(Li-O_(2))batteries.Herein,we propose a strategy to realize low charge overpotentials by co...Achieving low charge overpotentials represents one of the most critical challenges for pursuing highperformance lithium-oxygen(Li-O_(2))batteries.Herein,we propose a strategy to realize low charge overpotentials by confining the growth of lithium peroxide(Li_(2)O_(2))inside mesoporous channels of cathodes(CMK-8).The CMK-8 cathode with tortuous pore structures can extend the diffusion distance of lithium superoxide(LiO_(2))in the mesoporous channels,facilitating the further reduction of LiO_(2) to lithium peroxide(Li_(2)O_(2))inside the pores and preventing them to be diffused out of the pores.Therefore,Li_(2)O_(2) is trapped in the mesoporous channels of CMK-8 cathodes,ensuring a good Li_(2)O_(2)/CMK-8 contact interface.The CMK-8 electrode exhibits a low charge overpotential of 0.43 V and a good cycle life for 72 cycles with a fixed capacity of 500 m Ah g^(-1) at 0.1 A g^(-1).This study proposes a strategy to achieve a low charge overpotential by confining Li_(2)O_(2) growth in the mesoporous channels of cathodes.展开更多
基金This work was supported by the National Key Research and Development Project(Nos.2019YFA0705403,2022YFA1205300)the National Natural Science Foundation of China(No.T2293693)+3 种基金the Guangdong Innovative and Entrepreneurial Research Team Program(No.2017ZT07C341)the Guangdong Basic and Applied Basic Research Foundation(No.2020B0301030002)the Shenzhen Basic Research Project(Nos.WDZC20200824091903001,JSGG20220831105402004)Zhiyuan Xiong thanks the financial support from South China University of Technology.
文摘Hexagonal boron nitride nanosheets(BNNSs)exhibit remarkable thermal and dielectric properties.However,their self-assembly and alignment in macroscopic forms remain challenging due to the chemical inertness of boron nitride,thereby limiting their performance in applications such as thermal management.In this study,we present a coaxial wet spinning approach for the fabrication of BNNSs/polymer composite fibers with high nanosheet orientation.The composite fibers were prepared using a superacid-based solvent system and showed a layered structure comprising an aramid core and an aramid/BNNSs sheath.Notably,the coaxial fibers exhibited significantly higher BNNSs alignment compared to uniaxial aramid/BNNSs fibers,primarily due to the additional compressive forces exerted at the core-sheath interface during the hot drawing process.With a BNNSs loading of 60 wt%,the resulting coaxial fibers showed exceptional properties,including an ultrahigh Herman orientation parameter of 0.81,thermal conductivity of 17.2 W m^(-1)K^(-1),and tensile strength of 192.5 MPa.These results surpassed those of uniaxial fibers and previously reported BNNSs composite fibers,making them highly suitable for applications such as wearable thermal management textiles.Our findings present a promising strategy for fabricating high-performance composite fibers based on BNNSs.
基金the National Key R&D Program of China(2018AAA0103103).
文摘The perception module of advanced driver assistance systems plays a vital role.Perception schemes often use a single sensor for data processing and environmental perception or adopt the information processing results of various sensors for the fusion of the detection layer.This paper proposes a multi-scale and multi-sensor data fusion strategy in the front end of perception and accomplishes a multi-sensor function disparity map generation scheme.A binocular stereo vision sensor composed of two cameras and a light deterction and ranging(LiDAR)sensor is used to jointly perceive the environment,and a multi-scale fusion scheme is employed to improve the accuracy of the disparity map.This solution not only has the advantages of dense perception of binocular stereo vision sensors but also considers the perception accuracy of LiDAR sensors.Experiments demonstrate that the multi-scale multi-sensor scheme proposed in this paper significantly improves disparity map estimation.
基金supported byNationalNatural Science Foundation of China(52274205)and Project of Education Department of Liaoning Province(LJKZ0338).
文摘Automatic text summarization(ATS)plays a significant role in Natural Language Processing(NLP).Abstractive summarization produces summaries by identifying and compressing the most important information in a document.However,there are only relatively several comprehensively evaluated abstractive summarization models that work well for specific types of reports due to their unstructured and oral language text characteristics.In particular,Chinese complaint reports,generated by urban complainers and collected by government employees,describe existing resident problems in daily life.Meanwhile,the reflected problems are required to respond speedily.Therefore,automatic summarization tasks for these reports have been developed.However,similar to traditional summarization models,the generated summaries still exist problems of informativeness and conciseness.To address these issues and generate suitably informative and less redundant summaries,a topic-based abstractive summarization method is proposed to obtain global and local features.Additionally,a heterogeneous graph of the original document is constructed using word-level and topic-level features.Experiments and analyses on public review datasets(Yelp and Amazon)and our constructed dataset(Chinese complaint reports)show that the proposed framework effectively improves the performance of the abstractive summarization model for Chinese complaint reports.
基金supported by National Key R&D Program of China(Grant No.2018YFE0204302)National Natural Science Foundation of China(Grant No.52062015,No.61703160)+1 种基金the Talent Research Start-up Fund of Nanjing University of Aeronautics and Astronautics(YAH22019)Jiangsu High Level'Shuang-Chuang'Project.
文摘Existing signal control systems for urban traffic are usually based on traffic flow data from fixed location detectors.Because of rapid advances in emerging vehicular communication,connected vehicle(CV)-based signal control demonstrates significant improvements over existing conventional signal control systems.Though various CV-based signal control systems have been investigated in the past decades,these approaches still have many issues and drawbacks to overcome.We summarize typical components and structures of these existing CV-based urban traffic signal control systems and digest several important issues from the summarized vital concepts.Last,future research directions are discussed with some suggestions.We hope this survey can facilitate the connected and automated vehicle and transportation research community to efficiently approach next-generation urban traffic signal control methods and systems.
基金Supported by the National Natural Science Foundation of China(21406008)
文摘Using catalytic oxidative absorption for H_2S removal is of great interest due to its distinct advantages. However,traditional scrubbing process faces a great limitation in the confined space. Therefore, there is an urgent demand to develop high-efficiency process intensification technology for such a system. In this article, H_2S absorption experimental research was conducted in a rotating packed bed(RPB) reactor with ferric chelate absorbent and a mixture of N_2 and H_2S, which was used to simulate natural gas. The effects of absorbent p H value, gas–liquid ratio, gravity level of RPB, absorption temperature and character of the packing on the desulfurization efficiency were investigated. The results showed that H_2S removal efficiency could reach above 99.6% under the most of the experimental condition and above 99.9% under the optimal condition. A long-time continuous experiment was conducted to investigate the stability of the whole process combining absorption and regeneration. The result showed that the process could well realize simultaneous desulfurization and absorbent regeneration, and the H_2S removal efficiency kept relatively stable in the whole duration of 72 h. It can be clearly seen that high gravity technology desulfurization process, which is simple, high-efficiency, and space intensive, has a good prospect for industrial application of H_2S removal in confined space.
基金supported by the National Key Research and Development Plan of China (No.2016YFB0101102 )the Suzhou Tsinghua Innovation Initiative(No. 2016SZ0207)+2 种基金the National Natural Science Foundation of China(No.51375007)the Research Project of Key Laboratory of Advanced Manufacture Technology for Automobile Parts(Chongqing University of Technology),Ministry of Education (No.2015KLMT04)the Fundamental Research Funds for the Central Universities (No. NE2016002)
文摘Automotive collision avoidance technology can effectively avoid the accidents caused by dangerous traffic conditions or driver's manipulation errors.Moreover,it can promote the development of autonomous driving for intelligent vehicle in intelligent transportation.We present a collision avoidance system,which is composed of an evasive trajectory planner and a path following controller.Considering the stability of the vehicle in the conflict-free process,the evasive trajectory planner is designed by polynomial parametric method and optimized by genetic algorithm.The path following controller is proposed to make the car drive along the designed path by controlling the vehicle's lateral movement.Simulation results show that the vehicle with the proposed controller has good stability in the collision process,and it can ensure the vehicle driving in accordance with the planned trajectory at different speeds.The research results can provide a certain basis for the research and development of automotive collision avoidance technology.
文摘The influences of plastic deformation, aging treatment, and alloying elements on the texture of Cu-Cr-Zr alloys were explored. The texture component and intensity of Cu-Cr-Zr alloys under various working conditions after aging treatment were characterized using the orientation distributing function (ODF). The influence of Zr content on the texture of Cu-Cr-Zr alloys was also analyzed. The reduction pass and deformation level were primary factors influencing the texture. Rolling texture appeared in a rolled plate and the fibrous textures of {111} and {001} were detected after 80% deformation. Fibrous texture with a main constituent of {111} improved the tensile strength of the alloy wire. The texture contents of {110}<331> and {110}<112> were predominated, whereas, those of {113}<332> and {112}<111> were in the minority in the Cu-Cr-Zr alloy with a higher Zr content (>0.5wt%). However, in the samples with a lower Zr content (<0.1wt%), the texture contents of {113}<332>, {112}<111>, and {111}<110> were in the majority.
基金supported by National University of Singapore, the National Natural Science Foundation of China (NSFC 51572182, 11502036, 11372104, 11632004)the Natural Science Fund of the city of Chongqing (cstc2015jcyj A0577)The Key Program for International Science and Technology Cooperation Projects of the Ministry of Science and Technology of China (No. 2016YFE0125900)
文摘All-solid-state sodium-ion battery is regarded as the next generation battery to replace the current commercial lithium-ion battery, with the advantages of abundant sodium resources, low price and high-level safety. As one critical component in sodium-ion battery, solid-state electrolyte should possess superior operational safety and design simplicity, yet reasonable high room-temperature ionic conductivity. This paper gives a comprehensive review on the recent progress in solid-state electrolyte materials for sodium-ion battery, including inorganic ceramic/glass-ceramic, organic polymer and ceramic-polymer composite electrolytes, and also provides a comparison of the ionic conductivity in various solid-state electrolyte materials. The development of solid-state electrolytes suggests a bright future direction: all solid-state sodium-ion battery could be fully used to power all electric road vehicles, portable electronic devices and large-scale grid support.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0205800)the National Natural Science Foundation of China(Grant Nos.11734005,61307066,and 61450110442)+3 种基金the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20130630)the Doctoral Fund of Ministry of Education of China(Grant No.20130092120024)the Innovation Fund of School of Electronic Science and Engineering,Southeast University,China(Grant No.2242015KD006)the Scientific Research Foundation of Graduate School of Southeast University,China(Grant Nos.YBJJ1513 and YBJJ1613)
文摘Here,a plasmon-enhanced random laser was achieved by incorporating gold nanostars(NS) into disordered polymer and Cd Se/Zn S quantum dots(QDs) gain medium films,in which the surface plasmon resonance of gold NS can greatly enhance the scattering cross section and bring a large gain volume.The random distribution of gold NS in the gain medium film formed a laser-mode resonator.Under a single-pulse pumping,the scattering center of gold NS-based random laser exhibits enhanced performance of a lasing threshold of 0.8 m J/cm^2 and a full width as narrow as 6 nm at half maximum.By utilizing the local enhancement characteristic of the electric field at the sharp apexes of the gold NS,the emission intensity of the random laser was increased.In addition,the gold NS showed higher thermal stability than the silver nanoparticles,withstanding high temperature heating up to 200?C.The results of metal nanostructures with enriched hot spots and excellent temperature stability have tremendous potential applications in the fields of biological identification,medical diagnostics,lighting,and display devices.
基金financially supported by the National Natural Science Foundation of China (No. 51204046)the China Postdoctoral Science Foundation (No. 2015M581348)+2 种基金the Postdoctoral Science Foundation of Northeastern University (No. 20150302)the Doctoral Fund of the Ministry of Education of China (No. 20130042130001)the Science and Technology Program of Guangzhou, China (No. 2015B090926013)
文摘Developments in the contents of different typical inclusions in 3104 alloy melt were described during heating and holding processing. The settling process of inclusion particles was investigated by measuring the contents of inclusions in the surface, center, and bottom layers of the molten metal. In the results, main inclusions observed and determined by Prefil and PoD FA methods are MgO, Al_2O_3, spinel(MgAl_2O_4), and TiB_2 particles or thin films. It is found that some small particles of Al_2O_3 and MgO are transformed into spinel particles, and the formation rate increases as the temperature and the holding period of melt increase. The content of inclusions increases from 3.37 mm^2×kg^(-1) to 7.54 mm^2×kg^(-1) and then decreases to 3.08 mm^2×kg^(-1) after holding for 90 min. This is attributed to a settling phenomenon and a significant increase in settling velocity after holding for 60 min. The content of inclusion particles decreases by means of settlement and flotation in liquid aluminum with an increase in holding time. The theoretical analysis and experiment results are in essential agreement with those from industrial production.
基金Ministry of Education of Singapore Tier 2 Research grant(MOE2017-T2-2-029)China Jiangsu Nature Science Foundation(BK20181185).
文摘Growing evidence has shown that exposure to low ambient temperature poses a huge challenge to human health globally.Actually,cold stress is closely associated with a higher incidence of cardiovascular morbidity and mortality in winter or in cold regions.Cellular and molecular mechanisms underlying cardiovascular complications in response to cold exposure have yet to be fully clarified.Considering that cold exposure is an important risk of cardiovascular complications,it is necessary to clarify the molecular mechanism of cold stress-induced cardiovascular diseases and to develop effective intervention strategies.Hydrogen sulfide(H2S),nitric oxide(NO),and carbon monoxide(CO)are well-known gasotransmitters that are endogenously produced in many biological systems.Accumulating studies have demonstrated that these gasotransmitters play a critical role in a wide spectrum of physiological and/or pathophysiological processes by regulating numerous signaling pathways.These gas signal molecules are emerging as important players in cardiovascular homeostasis,and disruption of these gasotransmitters is critically implicated in cardiovascular anomalies,such as hypertension,atherosclerosis,myocardial ischemia,heart failure,and stroke.Also,evidence is emerging that H2S,NO,and CO may be involved in the pathologies of cold stress-induced cardiovascular ailments.In this review,we aim to highlight and discuss the recent advances towards the development of gasotransmitters-based therapeutics for cold stress-related cardiovascular pathogenesis.We believe that the effects of H2S,NO,and CO on cardiovascular regulation under cold environment will attract tremendous interest in the near future as they serve as novel regulators of cardiovascular biology in cold environment.
基金supported by Project of the National Twelfth Five-Year Research Program of China (Grants. 2014BAE03B02)
文摘Petroleum sulfonate is one of the most important surfactants used in surfactant flooding for enhanced oil recovery, which is mainly obtained by treating high-boiling petroleum fractions in a stirred tank reactor(STR) or in a fallingfilm reactor(FFR). The synthesis of petroleum sulfonate with ultra-low interfacial tension from viscous petroleum fractions was carried out in a rotating packed bed(RPB) reactor using dilute liquid sulfur trioxide as the sulfonating agent in this study. The effects of various experimental conditions on components content and oil-water interfacial tension(IFT) were investigated. Under the optimum conditions, the active matter content could reach up to 50.3% and the IFT could be equal to 4.7×10-3 m N/m. Compared with the traditional reactor, the active matter content is by 14.12% higher in the RPB as compared to that obtained in the STR. The uneven change of the test oil droplets during the IFT measurement was also discussed. The increase of heavy components content not only can eliminate the contraction phenomenon, but also can reduce the IFT to a minimum. This can be conducive to explaining the reason for producing IFT and the preparation of proper formulations for practical application.
基金This work is supported by the RIE Advanced Manufacturing and Engineering(AME)Programmatic Grant Project(Grant A18A5b0056,WBS:A-0005117-02-00)the Advanced Research and Technology Innovation Centre(ARTIC)Project(WBS:A-0005947-20-00)the Ministry of Education(MOE)of Singapore Tier 1 Project(WBS:A-0005138-01-00).
文摘Metal-organic frameworks(MOFs)have been extensively used for gas sorption,storage and separation owing to ultrahigh porosity,exceptional thermal stability,and wide structural diversity.However,when it comes to ultra-low concentration gas detection,technical bottlenecks of MOFs appear due to the poor adsorption capacity at ppm-/ppblevel concentration and the limited sensitivity for signal transduction.Here,we present hybrid MOF-polymer physi-chemisorption mechanisms integrated with infrared(IR)nanoantennas for highly selective and ultrasensitive CO_(2) detection.To improve the adsorption capacity for trace amounts of gas molecules,MOFs are decorated with amino groups to introduce the chemisorption while maintaining the structural integrity for physisorption.Additionally,leveraging all major optimization methods,a multi-hotspot strategy is proposed to improve the sensitivity of nanoantennas by enhancing the near field and engineering the radiative and absorptive loss.As a benefit,we demonstrate the competitive advantages of our strategy against the state-of-the-art miniaturized IR CO_(2) sensors,including low detection limit,high sensitivity(0.18%/ppm),excellent reversibility(variation within 2%),and high selectivity(against C_(2)H_(5)OH,CH_(3)OH,N_(2)).This work provides valuable insights into the integration of advanced porous materials and nanophotonic devices,which can be further adopted in ultra-low concentration gas monitoring in industry and environmental applications.
基金supports from the National Natural Science Foundation of China(22022204,21633013)the Natural Science Foundation of Jiangsu Province(BK20180248).
文摘Nitrile compounds are a class of high-value chemicals and versatile intermediates which can easily be transformed into a variety of useful products bearing functional groups such as carboxyl, carbamoyl, aminomethyl, ketyl and heterocyclic derivatives. Various thermal catalytic cyanation procedures have been devised and scaled up industrially while developing alternative methods are actively pursued. The access to these classes of molecules electrochemically offers greener alternatives to their preparation. The development of electrochemical synthesis of cyano-containing compounds under mild conditions with low energy consumption will imminently become indispensable approaches for industrial production of nitriles. The electrochemical cyanation presents many challenges from the toxicity of cyanide to the development of catalysts and the design of electrochemical cells. Electrochemical cyanation reaction offers promise to conveniently accessing nitriles but still requires efficient electro-catalysts, safe protocols and scale up considerations. This review discusses recent progress in the field of electrochemical synthesis of nitrile compounds placing emphasis on electro-synthetic and electro-catalytic mechanism aspects while making reference to original works to highlight the progress in this area.
基金Singapore MOE Tier Ⅱ grant R143-000-A29-112the National Research Foundation under the Grant of NRF2017NRF-NSFC001-007.
文摘Pore structure of hard carbon has a fundamental influence on the electrochemical properties in sodium-ion batteries(SIBs).Ultra-micropores(<0.5 nm)of hard carbon can function as ionic sieves to reduce the diffusion of slovated Na+but allow the entrance of naked Na^(+) into the pores,which can reduce the interficial contact between the electrolyte and the inner pores without sacrificing the fast diffusion kinetics.Herein,a molten diffusion-carbonization method is proposed to transform the micropores(>1 nm)inside carbon into ultra-micropores(<0.5 nm).Consequently,the designed carbon anode displays an enhanced capacity of 346 mAh g^(−1) at 30 mA g^(−1) with a high ICE value of~80.6%and most of the capacity(~90%)is below 1 V.Moreover,the high-loading electrode(~19 mg cm^(−2))exhibits a good temperature endurance with a high areal capacity of 6.14 mAh cm^(−2) at 25℃ and 5.32 mAh cm^(−2) at −20℃.Based on the in situ X-ray diffraction and ex situ solid-state nuclear magnetic resonance results,the designed ultra-micropores provide the extra Na+storage sites,which mainly contributes to the enhanced capacity.This proposed strategy shows a good potential for the development of high-performance SIBs.
基金J.G.Sun appreciates the scholarship support from China Scholarship Council(CSC)under grant No.201706050153.
文摘Carbonaceous materials are the most promising candidates as the anode for sodium-ion batteries (SIBs), however, they still suffer from low electric conductivity and sluggish sodium ion (Na+) reaction kinetics. Appropriate composition modulation using heteroatoms doping and structure optimization is highly desired. A basic empirical understanding of the structure-capacity relationship is also urgent in tackling the above problems. Herein, multi-functional nitrogen (N) doped carbon micro-rods with enlarged interlayer spacing are synthesized and investigated as the anode in SIBs, showing an ultra-stable capacity of 161.5 mAh g^(−1) at 2 A g^(−1) for over 5000 cycles. Experimental investigations and first-principle calculations indicate that the enlarged interlayer spacing can facilitate Na+ intercalation and N doping can guarantee the high electric conductivity and favorable electrochemical active sites. Additionally, pyridinic N is theoretically proved to be more effective to enhance Na+ adsorption than pyrrolic N due to the lower adsorption energy and stronger binding energy with Na+. Full SIBs show a high capacity and cyclability, making the biomass-derived carbon micro-rods to be a promising anode for practical SIBs applications.
文摘There is a lack of reported studies on how the long duration wearing of N95 respirators or surgical facemasks will affect the upper airway functions. Considering the frequency of mask wearing especially in hospitals and during an outbreak of influenza, it is essential to have such data documented. Therefore, the current study is to establish the effect of long duration wearing of N95 and surgical facemasks on upper airway functions. 47 staffs of National University Hospital Singapore in 2013 were recruited. Each of the volunteers wore both N95 respirator and surgical facemask for 3 hours on two different days. During the period of mask wearing, relative airflow rates were recorded. Smell function test was carried out before and after mask wearing. The results show that no significant change of smell test score was found after removal of both the two types of masks. With N95 respirator, more air was breathed into the upper airways compared to surgical facemask.
文摘Spinel cathode is one of promising candidatesfor high-performance lithium-ion batteries due toits high voltage and hence high energy.This kind ofmaterial has excellent rate performance with 3D lith-ium diffusion pathway and it is inexpensive,stableand environmentally friendly.AlthoughLi Mn1.5Ni0.5O4suffers from its limited capacity
基金the financial support from the National Natural Science Foundation of China(91645102)the Singapore MOE grant(R143-000-A29-112)the Hundred Talents Sailing Project of Jiangxi province,China。
文摘Achieving low charge overpotentials represents one of the most critical challenges for pursuing highperformance lithium-oxygen(Li-O_(2))batteries.Herein,we propose a strategy to realize low charge overpotentials by confining the growth of lithium peroxide(Li_(2)O_(2))inside mesoporous channels of cathodes(CMK-8).The CMK-8 cathode with tortuous pore structures can extend the diffusion distance of lithium superoxide(LiO_(2))in the mesoporous channels,facilitating the further reduction of LiO_(2) to lithium peroxide(Li_(2)O_(2))inside the pores and preventing them to be diffused out of the pores.Therefore,Li_(2)O_(2) is trapped in the mesoporous channels of CMK-8 cathodes,ensuring a good Li_(2)O_(2)/CMK-8 contact interface.The CMK-8 electrode exhibits a low charge overpotential of 0.43 V and a good cycle life for 72 cycles with a fixed capacity of 500 m Ah g^(-1) at 0.1 A g^(-1).This study proposes a strategy to achieve a low charge overpotential by confining Li_(2)O_(2) growth in the mesoporous channels of cathodes.