The outstanding performances of nanostructured allinorganic CsPbX_3(X = I, Br, Cl) perovskites in optoelectronic applications can be attributed to their unique combination of a suitable bandgap, high absorption coeffi...The outstanding performances of nanostructured allinorganic CsPbX_3(X = I, Br, Cl) perovskites in optoelectronic applications can be attributed to their unique combination of a suitable bandgap, high absorption coefficient, and long carrier lifetime, which are desirable for photodetectors. However, the photosensing performances of the CsPbI_3 nanomaterials are limited by their low charge-transport efficiency. In this study, a phototransistor with a bilayer structure of an organic semiconductor layer of 2,7-dioctyl [1] benzothieno[3,2-b] [1] benzothiophene and CsPbI_3 nanorod layer was fabricated. The high-quality CsPbI_3 nanorod layer obtained using a simple dip-coating method provided decent transistor performance of the hybrid transistor device.The perovskite layer efficiently absorbs light, while the organicsemiconductor layer acts as a transport channel for injected photogenerated carriers and provides gate modulation. The hybrid phototransistor exhibits high performance owing to the synergistic function of the photogating effect and field effect in the transistor,with a photoresponsivity as high as 4300 A W^(-1), ultra-high photosensitivity of 2.2 9 106, and excellent stability over 1 month.This study provides a strategy to combine the advantages of perovskite nanorods and organic semiconductors in fabrication of high-performance photodetectors.展开更多
Photodetectors based on amorphous InGaZnO(a-IGZO)thin film transistor(TFT)and halide perovskites have attracted attention in recent years.However,such a stack assembly of a halide perovskite layer/an a-IGZO channel,ev...Photodetectors based on amorphous InGaZnO(a-IGZO)thin film transistor(TFT)and halide perovskites have attracted attention in recent years.However,such a stack assembly of a halide perovskite layer/an a-IGZO channel,even with an organic semiconductor film inserted between them,easily has a very limited photoresponsivity.In this article,we investigate photoresponsive characteristics of TFTs by using CsPbX3(X=Br or I)quantum dots(QDs)embedded into the a-IGZO channel,and attain a high photoresponsivity over 10^3A·W^-1,an excellent detectivity in the order of 10^16 Jones,and a light-to-dark current ratio up to 10^5 under visible lights.This should be mainly attributed to the improved transfer efficiency of photoelectrons from the QDs to the a-IGZO channel.Moreover,spectrally selective photodetection is demonstrated by introducing halide perovskite QDs with different bandgaps.Thus,this work provides a novel strategy of device structure optimization for significantly improving the photoresponsive characteristics of TFT photodetectors.展开更多
Malignant tumors are one of the serious public health problems that threaten the survival time of human beings.They are prone to metastasis to distant organs and the central nervous system is one of the common target ...Malignant tumors are one of the serious public health problems that threaten the survival time of human beings.They are prone to metastasis to distant organs and the central nervous system is one of the common target organs.As it is difficult for chemotherapeutics,targeted drugs and other macromolecules to pass through the blood brain barrier(BBB),local radiation therapy is often used for treating intracranial primary or metastatic tumors.However,whether it is whole brain radiation therapy(WBRT)or stereotactic body radiation therapy(SBRT),the choice of radiation dose is limited by the side effects of radiation therapy on the surrounding normal brain tissues.Radiation-induced brain injury(RBI)can further develop into radiation necrosis(RN)in the late stage.Bevacizumab is often effective against RBI by antagonizing vascular endothelial growth factor(VEGF),but it still cannot completely reverse RN.Emerging treatment options such as human pluripotent stem-cell transplantation have made it possible to reverse the process of RN.展开更多
Due to their outstanding anti-flashover characteristics,composite insulators have been extensively applied in power systems.A lot of research has investigated flashover characteristics of hydrophobic specimens with ar...Due to their outstanding anti-flashover characteristics,composite insulators have been extensively applied in power systems.A lot of research has investigated flashover characteristics of hydrophobic specimens with artificial water droplets.However,the phenomenon is not consistent with that of the contaminated composite insulators.On the test specimens covered with water droplets,there is no obvious leakage current before the flashover and no obvious relationship between flashover voltage and the conductivity of water droplets.On the contaminated composite insulator surface,there are short continuous arcs on the insulators before critical flashover,making insulators look like a luminous lantern.Considering that under these two conditions,the proportion of water along the insulation distance is different,the flashover characteristic of“dry band-water band”on a hydrophobicity surface is analyzed in the present study.The influence of the water band parameter(including length,width,and conductivity)as well as the length of dry band is studied.On this basis,the arc generation and development process of the surface covered with“dry band-water band”is analyzed.The research results improve the understanding of the flashover process on contaminated composite insulators.展开更多
Composite insulators are generally considered to have excellent anti-pollution flashover performance,but recently there has been a flashover accident on the indoor clean insulator in China,which is suspected to be rel...Composite insulators are generally considered to have excellent anti-pollution flashover performance,but recently there has been a flashover accident on the indoor clean insulator in China,which is suspected to be related to the wetting of insulators through condensation.Therefore,this paper studied the water condensation on hydrophobic surfaces.The changes in the mass,length,and proportion of the water droplets on the hydrophobic surface during the wetting process were measured,and the influence of wetting degree on the flashover characteristics was studied.It was found that the insulator surface temperature lower than the dew point is a prerequisite for the wetting of the clean hydrophobic surface,and the wetting velocity increases with the electric field.The results could provide some reference for understanding the insulator flashover accidents.展开更多
Understanding the cracking process of layered tunnels requires a high-fidelity method.Improved smooth particle hydrodynamics(SPH),termed kernel broken SPH(KBSPH),was implemented to simulate the crack propagation and d...Understanding the cracking process of layered tunnels requires a high-fidelity method.Improved smooth particle hydrodynamics(SPH),termed kernel broken SPH(KBSPH),was implemented to simulate the crack propagation and deformation of layered rock cells and field layered tunnels with dip angles of 0°–90°,and the results were compared with those of the laboratory tests.Three attempts,including the bedding angle,interlayer distance,and lateral pressure coefficient,were made to investigate the crack propagation and deformation of layered tunnels.Finally,the pros and cons of the KBSPH method applied in the rock field were compared with those of other methods.The results indicate that the KBSPH can explicitly reproduce crack propagation by improving the kernel function with a totally damaged symbol,and the deformation responses have been captured reasonably.We infer that this method is effective and rapid in crack propagation and large deformation simulation for other types of rock tunnels.展开更多
Optoelectronic devices for light or spectral signal detection are desired for use in a wide range of applications,including sensing,imaging,optical communications,and in situ characterization.However,existing photodet...Optoelectronic devices for light or spectral signal detection are desired for use in a wide range of applications,including sensing,imaging,optical communications,and in situ characterization.However,existing photodetectors indicate only light intensities,whereas multiphotosensor spectrometers require at least a chip-level assembly and can generate redundant signals for applications that do not need detailed spectral information.Inspired by human visual and psychological light perceptions,the compression of spectral information into representative intensities and colours may simplify spectrum processing at the device level.Here,we propose a concept of spectrum projection using a bandgap-gradient semiconductor cell for intensity and colour perception.Bandgap-gradient perovskites,prepared by a halide-exchanging method via dipping in a solution,are developed as the photoactive layer of the cell.The fabricated cell produces two output signals:one shows linear responses to both photon energy and flux,while the other depends on only photon flux.Thus,by combining the two signals,the single device can project the monochromatic and broadband spectra into the total photon fluxes and average photon energies(i.e.,intensities and hues),which are in good agreement with those obtained from a commercial photodetector and spectrometer.Under changing illumination in real time,the prepared device can instantaneously provide intensity and hue results.In addition,the flexibility and chemical/bio-sensing of the device via colour comparison are demonstrated.Therefore,this work shows a human visual-like method of spectrum projection and colour perception based on a single device,providing a paradigm for high-efficiency spectrum-processing applications.展开更多
Neutrophils are considered as complex innate immune cells and play a critical role in maintaining intestinal mucosal homeostasis.They exert robust pro-inflammatory effects and recruit other immune cells in the acute p...Neutrophils are considered as complex innate immune cells and play a critical role in maintaining intestinal mucosal homeostasis.They exert robust pro-inflammatory effects and recruit other immune cells in the acute phase of pathogen infection and intestinal inflammation,but paradoxically,they also limit exogenousmicrobial invasion and facilitate mucosal restoration.Hyperactivation or dysfunction of neutrophils results in abnormal immune responses,leading to multiple autoimmune and inflammatory diseases including systemic lupus erythematosus,rheumatoid arthritis,and inflammatory bowel diseases(IBD).As a refractory intestinal inflammatory disease,the pathogenesis and progression of IBD are associated with complicated immune response processes in which neutrophils are profoundly involved.However,the consensus on potential roles of neutrophils in modulating pathogenic and repair processes of IBD remains not fully understood.Accumulated infiltrating neutrophils cross the epithelial barrier and contribute to microbial dysbiosis,aggravated intestinal architectural damage,compromised resolution of intestinal inflammation and increased risk of thrombosis during IBD.Paradoxically,activated neutrophils are also associated with effective elimination of invaded microbiota,promoted angiogenesis and tissue restoration of gutmucosa in IBD.Here,we discuss the beneficial and detrimental roles of neutrophils in the onset and resolution of intestinalmucosal inflammation,hoping to provide a precise overview of neutrophil functions in the pathogenesis of IBD.展开更多
基金supported by the National Key Research and Development Program of China (2017YFA0103904)the National Nature Science Foundation of China (51741302 and 51603151)+2 种基金Science & Technology Foundation of Shanghai (17JC1404600)the Fundamental Research Funds for the Central Universitiesthe support of College of Transportation Engineering,Tongji University’s Shanghai ‘‘Gaofeng’’ subject
文摘The outstanding performances of nanostructured allinorganic CsPbX_3(X = I, Br, Cl) perovskites in optoelectronic applications can be attributed to their unique combination of a suitable bandgap, high absorption coefficient, and long carrier lifetime, which are desirable for photodetectors. However, the photosensing performances of the CsPbI_3 nanomaterials are limited by their low charge-transport efficiency. In this study, a phototransistor with a bilayer structure of an organic semiconductor layer of 2,7-dioctyl [1] benzothieno[3,2-b] [1] benzothiophene and CsPbI_3 nanorod layer was fabricated. The high-quality CsPbI_3 nanorod layer obtained using a simple dip-coating method provided decent transistor performance of the hybrid transistor device.The perovskite layer efficiently absorbs light, while the organicsemiconductor layer acts as a transport channel for injected photogenerated carriers and provides gate modulation. The hybrid phototransistor exhibits high performance owing to the synergistic function of the photogating effect and field effect in the transistor,with a photoresponsivity as high as 4300 A W^(-1), ultra-high photosensitivity of 2.2 9 106, and excellent stability over 1 month.This study provides a strategy to combine the advantages of perovskite nanorods and organic semiconductors in fabrication of high-performance photodetectors.
基金Project supported by the National Natural Science Foundation of China(Grant No.61874029)the National Key Technologies R&D Program of China(Grant No.2015ZX02102-003).
文摘Photodetectors based on amorphous InGaZnO(a-IGZO)thin film transistor(TFT)and halide perovskites have attracted attention in recent years.However,such a stack assembly of a halide perovskite layer/an a-IGZO channel,even with an organic semiconductor film inserted between them,easily has a very limited photoresponsivity.In this article,we investigate photoresponsive characteristics of TFTs by using CsPbX3(X=Br or I)quantum dots(QDs)embedded into the a-IGZO channel,and attain a high photoresponsivity over 10^3A·W^-1,an excellent detectivity in the order of 10^16 Jones,and a light-to-dark current ratio up to 10^5 under visible lights.This should be mainly attributed to the improved transfer efficiency of photoelectrons from the QDs to the a-IGZO channel.Moreover,spectrally selective photodetection is demonstrated by introducing halide perovskite QDs with different bandgaps.Thus,this work provides a novel strategy of device structure optimization for significantly improving the photoresponsive characteristics of TFT photodetectors.
文摘Malignant tumors are one of the serious public health problems that threaten the survival time of human beings.They are prone to metastasis to distant organs and the central nervous system is one of the common target organs.As it is difficult for chemotherapeutics,targeted drugs and other macromolecules to pass through the blood brain barrier(BBB),local radiation therapy is often used for treating intracranial primary or metastatic tumors.However,whether it is whole brain radiation therapy(WBRT)or stereotactic body radiation therapy(SBRT),the choice of radiation dose is limited by the side effects of radiation therapy on the surrounding normal brain tissues.Radiation-induced brain injury(RBI)can further develop into radiation necrosis(RN)in the late stage.Bevacizumab is often effective against RBI by antagonizing vascular endothelial growth factor(VEGF),but it still cannot completely reverse RN.Emerging treatment options such as human pluripotent stem-cell transplantation have made it possible to reverse the process of RN.
基金supported by the National Natural Science Foundation of China(NO.51977118)。
文摘Due to their outstanding anti-flashover characteristics,composite insulators have been extensively applied in power systems.A lot of research has investigated flashover characteristics of hydrophobic specimens with artificial water droplets.However,the phenomenon is not consistent with that of the contaminated composite insulators.On the test specimens covered with water droplets,there is no obvious leakage current before the flashover and no obvious relationship between flashover voltage and the conductivity of water droplets.On the contaminated composite insulator surface,there are short continuous arcs on the insulators before critical flashover,making insulators look like a luminous lantern.Considering that under these two conditions,the proportion of water along the insulation distance is different,the flashover characteristic of“dry band-water band”on a hydrophobicity surface is analyzed in the present study.The influence of the water band parameter(including length,width,and conductivity)as well as the length of dry band is studied.On this basis,the arc generation and development process of the surface covered with“dry band-water band”is analyzed.The research results improve the understanding of the flashover process on contaminated composite insulators.
基金Shenzhen Excellent Technological and Innovative Talent Training Project,Grant/Award Number:RCBS20200714114956357National Natural Science Youth Fund of China,Grant/Award Number:52007095National Natural Science Fund of China,Grant/Award Number:51907178。
文摘Composite insulators are generally considered to have excellent anti-pollution flashover performance,but recently there has been a flashover accident on the indoor clean insulator in China,which is suspected to be related to the wetting of insulators through condensation.Therefore,this paper studied the water condensation on hydrophobic surfaces.The changes in the mass,length,and proportion of the water droplets on the hydrophobic surface during the wetting process were measured,and the influence of wetting degree on the flashover characteristics was studied.It was found that the insulator surface temperature lower than the dew point is a prerequisite for the wetting of the clean hydrophobic surface,and the wetting velocity increases with the electric field.The results could provide some reference for understanding the insulator flashover accidents.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFC1509702)the National Natural Science Foundation of China(Grant Nos.41731283,42007252).
文摘Understanding the cracking process of layered tunnels requires a high-fidelity method.Improved smooth particle hydrodynamics(SPH),termed kernel broken SPH(KBSPH),was implemented to simulate the crack propagation and deformation of layered rock cells and field layered tunnels with dip angles of 0°–90°,and the results were compared with those of the laboratory tests.Three attempts,including the bedding angle,interlayer distance,and lateral pressure coefficient,were made to investigate the crack propagation and deformation of layered tunnels.Finally,the pros and cons of the KBSPH method applied in the rock field were compared with those of other methods.The results indicate that the KBSPH can explicitly reproduce crack propagation by improving the kernel function with a totally damaged symbol,and the deformation responses have been captured reasonably.We infer that this method is effective and rapid in crack propagation and large deformation simulation for other types of rock tunnels.
基金supported by the National Natural Science Foundation of China(61874029)the National Key Technologies R&D Programme of China(2015ZX02102-003).
文摘Optoelectronic devices for light or spectral signal detection are desired for use in a wide range of applications,including sensing,imaging,optical communications,and in situ characterization.However,existing photodetectors indicate only light intensities,whereas multiphotosensor spectrometers require at least a chip-level assembly and can generate redundant signals for applications that do not need detailed spectral information.Inspired by human visual and psychological light perceptions,the compression of spectral information into representative intensities and colours may simplify spectrum processing at the device level.Here,we propose a concept of spectrum projection using a bandgap-gradient semiconductor cell for intensity and colour perception.Bandgap-gradient perovskites,prepared by a halide-exchanging method via dipping in a solution,are developed as the photoactive layer of the cell.The fabricated cell produces two output signals:one shows linear responses to both photon energy and flux,while the other depends on only photon flux.Thus,by combining the two signals,the single device can project the monochromatic and broadband spectra into the total photon fluxes and average photon energies(i.e.,intensities and hues),which are in good agreement with those obtained from a commercial photodetector and spectrometer.Under changing illumination in real time,the prepared device can instantaneously provide intensity and hue results.In addition,the flexibility and chemical/bio-sensing of the device via colour comparison are demonstrated.Therefore,this work shows a human visual-like method of spectrum projection and colour perception based on a single device,providing a paradigm for high-efficiency spectrum-processing applications.
基金This work is supported by the National Natural Science Foundation of China(Grants No.81630017 and 91942312).
文摘Neutrophils are considered as complex innate immune cells and play a critical role in maintaining intestinal mucosal homeostasis.They exert robust pro-inflammatory effects and recruit other immune cells in the acute phase of pathogen infection and intestinal inflammation,but paradoxically,they also limit exogenousmicrobial invasion and facilitate mucosal restoration.Hyperactivation or dysfunction of neutrophils results in abnormal immune responses,leading to multiple autoimmune and inflammatory diseases including systemic lupus erythematosus,rheumatoid arthritis,and inflammatory bowel diseases(IBD).As a refractory intestinal inflammatory disease,the pathogenesis and progression of IBD are associated with complicated immune response processes in which neutrophils are profoundly involved.However,the consensus on potential roles of neutrophils in modulating pathogenic and repair processes of IBD remains not fully understood.Accumulated infiltrating neutrophils cross the epithelial barrier and contribute to microbial dysbiosis,aggravated intestinal architectural damage,compromised resolution of intestinal inflammation and increased risk of thrombosis during IBD.Paradoxically,activated neutrophils are also associated with effective elimination of invaded microbiota,promoted angiogenesis and tissue restoration of gutmucosa in IBD.Here,we discuss the beneficial and detrimental roles of neutrophils in the onset and resolution of intestinalmucosal inflammation,hoping to provide a precise overview of neutrophil functions in the pathogenesis of IBD.
基金supported by the National Natural Science Foundation of China (51603151 and 51741302)the National Key Research and Development Program of China (2017YFA0103900 & 2017YFA0103904)+1 种基金 Science & Technology Foundation of Shanghai (17JC1404600) the Fundamental Research Funds for the Central Universities.
基金supported by the National Natural Science Foundation of China (51741302, 51603151 and 51373123)the National Key Research and Development Program of China (2017YFA0103900 and 2017YFA0103904)+1 种基金Science and Technology Foundation of Shanghai (17JC1404600)the Fundamental Research Funds for the Central Universities
