Foreign language teaching practice is developing rapidly,but research on foreign language teacher learning is currently relatively fragmented and unstructured.The book Foreign Language Teacher Learning,written by Prof...Foreign language teaching practice is developing rapidly,but research on foreign language teacher learning is currently relatively fragmented and unstructured.The book Foreign Language Teacher Learning,written by Professor Kang Yan from Capital Normal University,published in September 2022,makes a systematic introduction to foreign language teacher learning,which to some extent makes up for this shortcoming.Her book presents the lineage of foreign language teacher learning research at home and abroad,analyzes both theoretical and practical aspects,reviews the cuttingedge research results,and foresees the future development trend,painting a complete research picture for researchers in the field of foreign language teaching and teacher education as well as front-line teachers interested in foreign language teacher learning.This is an important inspiration for conducting foreign language teacher learning research in the future.And this paper makes a review of the book from aspects such as its content,major characteristics,contributions and limitations.展开更多
The corrosion behaviour of Mg−6Gd−3Y−1Zn−0.3Ag(wt.%)alloy components with different sizes after cooling was investigated.The alloys in the small components(SC)cooled fast,which were composed ofα-Mg matrix and coarse ...The corrosion behaviour of Mg−6Gd−3Y−1Zn−0.3Ag(wt.%)alloy components with different sizes after cooling was investigated.The alloys in the small components(SC)cooled fast,which were composed ofα-Mg matrix and coarse long-period stacking ordered(LPSO)phases.The alloys in the large components(LC)cooled slowly,and there were thin lamellar LPSO phases precipitating inside the grains,except forα-Mg matrix and coarse LPSO phases.The hydrogen evolution test revealed that the corrosion rate of LC sample was higher than that of SC sample.Electrochemical impedance spectroscopy(EIS)test showed that the surface film on LC alloys provided worse protection.The corrosion morphologies indicated that the precipitation of the thin lamellar LPSO phases in LC sample caused severe micro-galvanic corrosion,which accelerated the rupture of the surface film.展开更多
Objective To evaluate the infectivity of severe acute respiratory syndrome （SARS） during its incubation period by investigating chains of transmission and individuals isolated for medical observation with a view to ...Objective To evaluate the infectivity of severe acute respiratory syndrome （SARS） during its incubation period by investigating chains of transmission and individuals isolated for medical observation with a view to providing scientific evidence for updating protocols of medical isolation. Methods Individuals related with the two SARS chains of transmission in Beijing in 2003 and a group of individuals isolated for medical observation in Haidian district of Beijing during the SARS outbreak were selected as subjects of study. Contactors with SARS patients and those with symptom development following the contacts were investigated via questionnaire. Serum samples were collected from super transmitters and tested for SARS-CoV antibody by neutralization test and enzyme linked immunosorbent assay （ELISA）. Results A total of 1 112 contactors were investigated in three surveys. Of them, 669 had a history of close contact with symptomatic SARS patients, 101 developed symptoms with a rate of 15.1%, 363 had a history of close contact with patients in their incubation period, none of whom developed symptoms （0%）. Serum samples were collected fi＇om 32 highly-exposed individuals, of whom 13 developing SARS symptoms atter contact had serum samples positive for SARS-CoV antibody. Samples collected from the asymptomatic contactors were all negative for SARS-CoV antibody. Conclusion SARS cases are infectious only during their symptomatic period and are non-infectious during the incubation period. Isolation for medical observation should be placed for individuals who are in close contact with symptomatic SARS patients. The results of our study are of decisive significance for the Ministry of Health to the definition of SARS close contactor.展开更多
BACKGROUND Closed reduction and internal fixation with intramedullary nails has been widely accepted for treating intertrochanteric fractures.AIM To focus on how to avoid displacement of the lesser trochanter in unsta...BACKGROUND Closed reduction and internal fixation with intramedullary nails has been widely accepted for treating intertrochanteric fractures.AIM To focus on how to avoid displacement of the lesser trochanter in unstable intertrochanteric fractures.METHODS We developed a lesser trochanteric reduction fixator for treating intertrochanteric fractures through fixing the lesser trochanter by combining the loop plate through the fixator after reduction by the reducer.Five patients with intertrochanteric fractures treated with the newly developed lesser trochanteric reduction fixator and loop plate combined with intramedullary nails,and 20 patients with intertrochanteric fractures treated with simple intramedullary nails were selected from December 2020 to March 2021.RESULTS The postoperative Harris hip score was significantly higher in patients treated with the lesser trochanteric reduction fixator than in patients treated without the lesser trochanteric reduction fixator,which indicated that this lesser trochanteric reduction fixator had a positive impact on rehabilitation of the hip joint after surgery and could significantly improve the quality of life of patients.CONCLUSION We fully realize the significance of trochanteric reduction and fixation,namely,reconstruction of structures under pressure,in the treatment of intertrochanteric fractures.As long as the general condition of patients is favorable and they are willing to undergo surgery,fixation of the main fracture end should be performed and the lesser trochanter should be reduced and fixed at the same time.展开更多
In this work,we reported a high-performance-based ultraviolet-visible(UV-VIS)photodetector based on a TiO_(2)@GaO_(x)N_(y)-Ag heterostructure.Ag particles were introduced into TiO_(2)@GaO_(x)N_(y)to enhance the visibl...In this work,we reported a high-performance-based ultraviolet-visible(UV-VIS)photodetector based on a TiO_(2)@GaO_(x)N_(y)-Ag heterostructure.Ag particles were introduced into TiO_(2)@GaO_(x)N_(y)to enhance the visible light detection perfor-mance of the heterojunction device.At 380 nm,the responsivity and detectivity of TiO_(2)@GaO_(x)N_(y)-Ag were 0.94 A/W and 4.79×109 Jones,respectively,and they increased to 2.86 A/W and 7.96×1010 Jones at 580 nm.The rise and fall times of the response were 0.19/0.23 and 0.50/0.57 s,respectively.Uniquely,at 580 nm,the responsivity of fabricated devices is one to four orders of magnitude higher than that of the photodetectors based on TiO_(2),Ga_(2)O_(3),and other heterojunctions.The excellent optoelectronic characteristics of the TiO_(2)@GaO_(x)N_(y)-Ag heterojunction device could be mainly attributed to the synergistic effect of the type-Ⅱband structure of the metal-semiconductor-metal heterojunction and the plasmon resonance effect of Ag,which not only effectively promotes the separation of photogenerated carriers but also reduces the recombination rate.It is fur-ther illuminated by finite difference time domain method(FDTD)simulation and photoelectric measurements.The TiO_(2)@GaO_(x)N_(y)-Ag arrays with high-efficiency detection are suitable candidates for applications in energy-saving communica-tion,imaging,and sensing networks.展开更多
The 20th century has witnessed three global influenza pandemics attacking mankind, namely the 1918 Spanish pandemic （H1N1 subgroup）, the 1957 Asian pandemic （H2N2 subgroup） and the 1968 Hong Kong pandemic （H3N2 s...The 20th century has witnessed three global influenza pandemics attacking mankind, namely the 1918 Spanish pandemic （H1N1 subgroup）, the 1957 Asian pandemic （H2N2 subgroup） and the 1968 Hong Kong pandemic （H3N2 subgroup）. The first pandemic swept throughout the entire world within six to nine months, which affected 400 million people, accounting for 20% of the total world population, and 40 to 50 million deaths which were more than the total deaths in World War I, resulting the worst catastrophe in the history of human infectious diseases[1]. At the moment, the world is threatened by an avian influenza pandemic and people are concerned about a potential worldwide human influenza pandemic.展开更多
[Objectives]To explore the active components and mechanism of Bupleurum and Asarum in the treatment of traumatic brain injury(TBI).[Methods]All the active components and potential action targets of Bupleurum and Asaru...[Objectives]To explore the active components and mechanism of Bupleurum and Asarum in the treatment of traumatic brain injury(TBI).[Methods]All the active components and potential action targets of Bupleurum and Asarum pairs were collected by online platform Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP)database and literature search.Target genes related to traumatic brain injury were obtained by Online Mendelian Inheritance in Man(OMMI),Therapeutic Target Database(TTD),PharmGKB,Genecards and Drugbank.The"drug-ingredient-target"network diagram was constructed by using Cytoscape software.Venny 2.1.0 was used to integrate the intersection targets of drug targets and disease targets,and the String platform was used to construct a target protein-protein interaction network(PPI).Topological analysis and core target screening of the constructed PPI network were performed using the"CytoNCA"plug-in in Cytoscape software.Gene Ontology(GO)annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analysis were performed on the intersection targets using the DAVID database.Finally,Autodock and Pymol software were used to simulate the binding activity of key candidate active components and core genes.[Results]25 active components were screened from Bupleurum-Asarum and 111 potential targets involved in the disease process.GO analysis and KEGG results showed that potential therapeutic targets were mainly enriched in biological processes such as inflammatory response,oxidative stress,cell membrane repair,and cytokine regulation.Network analysis and molecular docking showed that the key compounds of Bupleurum and Asarum were kaempferol and quercetin,which were well docked with the active pockets of four core genes of traumatic brain injury.[Conclusions]Bupleurum and Asarum may be involved in the regulation of inflammatory response,oxidative stress,cell membrane repair through multiple targets and multiple pathways in the treatment of traumatic brain injury.展开更多
The development of host-vip MOF luminescent composites has attracted considerable attention. However,it is still a challenge to reasonably design large scale conjugated polycarboxylic acids metal-organic framework (...The development of host-vip MOF luminescent composites has attracted considerable attention. However,it is still a challenge to reasonably design large scale conjugated polycarboxylic acids metal-organic framework (MOF) and modulate donor-acceptor interaction. Herein,a series of isostructural 3D porous lanthanide MOF [Ln_(2)(BINDI)0.5(NO_(3))(DMA)(H_(2)O)]∙DMA∙2.5H_(2)O (Ln = La (1),Ce (2),Pr (3) and Nd (4);H_(4)BINDI (N,N’-bis(5-isophthalic acid)-1,4,5,8-naphthalenediimide) were synthesized. Considering the electron-deficient performances of Ln-BINDI MOFs,D-A type composites Ln-MOFs (1—4@H_(4)TBAPy) were prepared via the incorporation of electron-rich H_(4)TBAPy (1,3,6,8-tetrakis(p-benzoic acid) pyrene),which more improved the luminescence performance of complexes 1—4 and can be used as fluorescence sensors for the detection of nitro compounds and aldehydes. High sensitivity of 1@H_(4)TBAPy towards pNBA,pNA PNP,DNP,and TNP could be achieved through hydrogen bond interactions between MOF and analytes,as well as the π-π interaction between H_(4)TBAPy and the naphthalene ring of BINDI,thus the fluorescence quenching efficiency of 1@H_(4)TBAPy was better than that of the complex 1. In addition,it is found that 1@H_(4)TBAPy has high selectivity and sensitivity to aromatic aldehyde SA,5-Mesal and HMBA. Such strategy to enhance the emission of NDI based Ln-BINDI MOFs,will open up an avenue to obtain more fluorescent MOFs for sensing.展开更多
All-solution processed organic solar cells are the ultimate aim of printable photovoltaics,but their electrical losses arising from poor contact of top electrodes greatly limit efficiency improvement.To solve the prob...All-solution processed organic solar cells are the ultimate aim of printable photovoltaics,but their electrical losses arising from poor contact of top electrodes greatly limit efficiency improvement.To solve the problem,a solution-processed hybrid top electrode was constructed using silver nanowires(AgNWs)as the skeleton and ZnO nanoparticles(ZnO-NPs)as the matrix.When constructing the skeleton,a spin-rinsing treatment was first used to reduce the amount of the residual insulating polyvinylpyrrolidone wrapped around the AgNWs to promote intimate contact among the AgNWs in the skeleton.Then,the ZnO-NPs matrix was deposited onto the AgNWs skeleton,bridging the AgNWs skeleton with the underlayer ZnO-NPs electron transporting layer(ETL).The underlayer ZnO-NPs ETL can also induce the growth of the ZnO-NPs matrix to minimize lattice mismatch,which creates additional transport channels from the ETL to the AgNWs skeleton for charge collection.As a result,the obtained electrode significantly enhances the electrical contact in the device,thus delivering record power conversion efficiencies of 16.04%and 14.54%for rigid and flexible all-solution processed OSCs,respectively.展开更多
The computational complexity of privacy information retrieval protocols is often linearly related to database size.When the database size is large,the efficiency of privacy information retrieval protocols is relativel...The computational complexity of privacy information retrieval protocols is often linearly related to database size.When the database size is large,the efficiency of privacy information retrieval protocols is relatively low.This paper designs an effective privacy information retrieval model based on hybrid fully homomorphic encryption.The assignment method is cleverly used to replace a large number of homomorphic encryption operations.At the same time,the multiplicative homomorphic encryption scheme is first used to deal with the large-scale serialization in the search,and then the fully homomorphic encryption scheme is used to deal with the remaining simple operations.The depth of operations supported by the fully homomorphic scheme no longer depends on the size of the database,but only needs to support the single homomorphic encryption scheme to decrypt the circuit depth.Based on this hybrid homomorphic encryption retrieval model,the efficiency of homomorphic privacy information retrieval model can be greatly improved.展开更多
The performance of flexible organic solar cells(OSCs)significantly relies on the quality of transparent flexible electrode.Here,we used silver nanowires(AgNWs)with various weight ratios to dope high-conductive poly(3,...The performance of flexible organic solar cells(OSCs)significantly relies on the quality of transparent flexible electrode.Here,we used silver nanowires(AgNWs)with various weight ratios to dope high-conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate(PH1000)to optimize the optical and electronic properties of PH1000 film.A high-quality flexible composite electrode PET/Ag-mesh/PH1000:AgNWs-20 with smooth surface,a low sheet resistance of 6Ω/sq and a high transmittance of 86%at 550-nm wavelength was obtained by doping 20 wt%AgNWs to PH1000(PH1000:AgNWs-20).The flexible OSCs based on the PET/Ag-mesh/PH1000:AgNWs-20 electrode delivered a power conversion efficiency(PCE)of12.07%with an open circuit voltage(Voc)of 0.826 V,a short-circuit current density(Jsc)of 20.90 m A/cm2and a fill factor(FF)of69.87%,which is the highest reported PCE for the flexible indium-tin oxide(ITO)-free OSCs.This work demonstrated that the flexible composite electrodes of PET/Ag-mesh/PH1000:AgNWs are promising alternatives for the conventional PET/ITO electrode,and open a new avenue for developing high-performance flexible transparent electrode for optoelectronic devices.展开更多
Casting aluminum(Al)alloys have been widely used in the automotive industry to improve fuel economy as well as to reduce greenhouse gas(GHG)emissions in the vehicle use phase.However,the casting Al alloys used for loa...Casting aluminum(Al)alloys have been widely used in the automotive industry to improve fuel economy as well as to reduce greenhouse gas(GHG)emissions in the vehicle use phase.However,the casting Al alloys used for load-bearing body and chassis components today are mostly made from primary Al with a low impurity Fe content typically less than 0.2 wt.%,owing to the requirements for high ductility and adequate fatigue strength.Primary Al is made directly from alumina which was refined from aluminum ore(bauxite),using an electrolytic process which consumes a lot of energy and produces GHG emissions that are much higher than those from steel making.The objective of this paper is to present a Unified Casting(UniCast)Al alloy concept as a sustainable materials solution for vehicle lightweighting.The UniCast alloy chemistry is intentionally designed to be more tolerant of Fe impurity.This chemistry can not only satisfy the requirements on castability,but also deliver mechanical properties needed for a variety of thin-walled and thick-walled automotive structural components that are produced by various casting processes.The UniCast alloy concept will contribute to the establishment of a closed-loop recycling system in the future as the shredded scrap obtained from the disposed end-of-life vehicles can be directly recycled back into UniCast alloy ingot with a more efficient sorting process.In addition,by setting the upper limit of Fe content in the UniCast alloy to a higher level,it will become possible to use a high fraction of post-consumer scraps to produce this alloy.To demonstrate the feasibility of this concept,an exemplary UniCast alloy chemistry has been elaborated in this article.Furthermore,challenges and future research opportunities related to the realization of UniCast alloy concept in the automotive industry are discussed.It is hoped that this article will be of great implication to industrial researchers and academicians for making concerted efforts to establish closed-loop recycling of Al castings for the automotive and other transportation industry segments.展开更多
Recent advances in non-fullerene acceptors(NFAs)like Y6 have pushed the power conversion efficiencies(PCEs)of organic solar cells(OSCs)above 19%.However,the harsh fabrication conditions,such as the use of the highly v...Recent advances in non-fullerene acceptors(NFAs)like Y6 have pushed the power conversion efficiencies(PCEs)of organic solar cells(OSCs)above 19%.However,the harsh fabrication conditions,such as the use of the highly volatile chloroform(CF)solvent and the thermal annealing process,are not suitable for large-area printing technologies and environmental standards.Here,a series of vip molecules,BT2O,BTO,and BT4O,are designed and synthesized with different numbers of oligo ethylene glycol(OEG)repeating units in side chains.All these vip molecules could tune the crystallization kinetics of the annealing-free host-vip active layers by inducing the self-assembly of Y6 in non-halogenated paraxylene(PX)solution.The increasing number of OEG repeating units in vip molecules could enhance the molecular assembly ability but molecular stacking steric hindrance simultaneously.Therefore,BTO with three OEG repeating units blended with PM6:PM7:Y6 delivers the highest PCE of 17.78%.Our results demonstrate controlling the crystallization kinetics via delicate side-chain engineering of vip molecules is an effective way to achieve efficient OSCs in non-halogenated solution.展开更多
Inorganic micro light-emitting diodes(micro-LEDs)based on II-V compound semiconductors have been widely studied for self-emissive displays.From chips to applications,integration technology plays an indispensable role ...Inorganic micro light-emitting diodes(micro-LEDs)based on II-V compound semiconductors have been widely studied for self-emissive displays.From chips to applications,integration technology plays an indispensable role in micro-LED displays.展开更多
Deep-ultraviolet(DUV)phototransistors have shown great potential applications in UV imaging,artificial intelligence,and wearable optoelectronics.Among a large number of wide bandgap semiconductors,the quasi-two-dimens...Deep-ultraviolet(DUV)phototransistors have shown great potential applications in UV imaging,artificial intelligence,and wearable optoelectronics.Among a large number of wide bandgap semiconductors,the quasi-two-dimensionalβ-Ga_(2)O_(3) is considered as an ideal candidate for DUV photodetector applications.Herein,we report a high responsivity(R)and fully flexible Ta-dopedβ-Ga_(2)O_(3) DUV phototransistor which exhibits outstanding optoelectrical properties with a high R of 1.32×10^(6) A/W,a large detectivity of 5.68×10^(14) Jones,a great photo-to-dark current ratio of 1.10×10^(10)%,a high external quantum efficiency of 6.60×10^(8)%,and an ultra-fast response time of~3.50 ms.Besides,the flexible Ta-dopedβ-Ga_(2)O_(3) device also displays high reliability and mechanical flexibility that can sustain well after over 1×10^(4) bending cycles.Moreover,high-contrast imaging of UV light was obtained on the flexible DUV detector arrays,which can be efficiently trained and recognized by an artificial neural network.Our findings offer a perspective to develop wearable optoelectronics and UV imaging based on high-performance flexibleβ-Ga_(2)O_(3) DUV phototransistors,providing an inspiration for the future work in artificial intelligence and bionic robot fields.展开更多
Thermal-mechanical processing of magnesium-based materials is an effective method to tailor the hydrogen storage performance.In this study,Mg-Ni-Gd-Y-Zn-Cu alloys were prepared by Direct Chill(DC)casting,with and with...Thermal-mechanical processing of magnesium-based materials is an effective method to tailor the hydrogen storage performance.In this study,Mg-Ni-Gd-Y-Zn-Cu alloys were prepared by Direct Chill(DC)casting,with and without extrusion process.The influences of microstructure evolution,introduced by DC casting and thermal-mechanical processing,on the hydrogen storage performance of Mg-Ni-Gd-Y-ZnCu alloys were comprehensively explored,using analytical electron microscopy and in-situ synchrotron powder X-ray diffraction.The result shows that the extruded alloy yields higher hydrogen absorption capacity and faster hydrogen ab/desorption kinetics.As subjected to extrusion processing,theα-Mg grains in the microstructure were significantly refined and a large number of 14H type long-period stacking ordered(LPSO)phases appeared on theα-Mg matrix.After activation,there were more nanosized Gd hydride/Mg2Ni intermetallics and finer chips.These modifications synergistically enhance the hydrogen storage properties.The findings have implications for the alloy design and manufacturing of magnesiumbased hydrogen storage materials with the advantages of rapid mass production and anti-oxidation.展开更多
Deep ultraviolet(DUV)phototransistors are key integral of optoelectronics bearing a wide spectrum of applications in flame sensor,military detector,oil spill detection,biological sensor,and artificial intelligence fie...Deep ultraviolet(DUV)phototransistors are key integral of optoelectronics bearing a wide spectrum of applications in flame sensor,military detector,oil spill detection,biological sensor,and artificial intelligence fields.In order to further improve the responsivity of UV photodetectors based onβ-Ga_(2)O_(3),in present work,high-performanceβ-Ga_(2)O_(3) phototransistors with local back-gate structure were experimentally demonstrated.The phototransistor shows excellent DUV photoelectrical performance with a high responsivity of 1.01×107 A/W,a high external quantum efficiency of 5.02×109%,a sensitive detectivity of 2.98×1015 Jones,and a fast rise time of 0.2 s under 250 nm illumination.Besides,first-principles calculations reveal the decent stability ofβGa_(2)O_(3) nanosheet against oxidation and humidity without significant performance degradations.Additionally,the hexagonal boron nitride(h-BN)/β-Ga_(2)O_(3) phototransistor can behave as a photonic synapse with ultralow power consumption of~9.6 fJ per spike,which shows its potential for neuromorphic computing tasks such as facial recognition.Thisβ-Ga_(2)O_(3) phototransistor will provide a perspective for the next generation optoelectrical systems.展开更多
The unipolar photocurrent in conventional photodiodes(PDs)based on photovoltaic effect limits the output modes and potential versatility of these devices in photodetection.Bipolar photodiodes with photocurrent switchi...The unipolar photocurrent in conventional photodiodes(PDs)based on photovoltaic effect limits the output modes and potential versatility of these devices in photodetection.Bipolar photodiodes with photocurrent switching are emerging as a promising solution for obtaining photoelectric devices with unique and attractive functions,such as optical logic operation.Here,we design an all-solid-state chip-scale ultraviolet(UV)PD based on a hybrid GaN heterojunction with engineered bipolar polarized electric field.By introducing the polarization-induced photocurrent switching effect,the photocurrent direction can be switched in response to the wavelength of incident light at 0 V bias.In particular,the photocurrent direction exhibits negative when the irradiation wavelength is less than 315 nm,but positive when the wavelength is longer than 315 nm.The device shows a responsivity of up to−6.7 mA/W at 300 nm and 5.3 mA/W at 340 nm,respectively.In particular,three special logic gates in response to different dual UV light inputs are demonstrated via a single bipolar PD,which may be beneficial for future multifunctional UV photonic integrated devices and systems.展开更多
文摘Foreign language teaching practice is developing rapidly,but research on foreign language teacher learning is currently relatively fragmented and unstructured.The book Foreign Language Teacher Learning,written by Professor Kang Yan from Capital Normal University,published in September 2022,makes a systematic introduction to foreign language teacher learning,which to some extent makes up for this shortcoming.Her book presents the lineage of foreign language teacher learning research at home and abroad,analyzes both theoretical and practical aspects,reviews the cuttingedge research results,and foresees the future development trend,painting a complete research picture for researchers in the field of foreign language teaching and teacher education as well as front-line teachers interested in foreign language teacher learning.This is an important inspiration for conducting foreign language teacher learning research in the future.And this paper makes a review of the book from aspects such as its content,major characteristics,contributions and limitations.
基金the financial supports from the National Natural Science foundation of China(Nos.51574291,51874367).
文摘The corrosion behaviour of Mg−6Gd−3Y−1Zn−0.3Ag(wt.%)alloy components with different sizes after cooling was investigated.The alloys in the small components(SC)cooled fast,which were composed ofα-Mg matrix and coarse long-period stacking ordered(LPSO)phases.The alloys in the large components(LC)cooled slowly,and there were thin lamellar LPSO phases precipitating inside the grains,except forα-Mg matrix and coarse LPSO phases.The hydrogen evolution test revealed that the corrosion rate of LC sample was higher than that of SC sample.Electrochemical impedance spectroscopy(EIS)test showed that the surface film on LC alloys provided worse protection.The corrosion morphologies indicated that the precipitation of the thin lamellar LPSO phases in LC sample caused severe micro-galvanic corrosion,which accelerated the rupture of the surface film.
文摘Objective To evaluate the infectivity of severe acute respiratory syndrome （SARS） during its incubation period by investigating chains of transmission and individuals isolated for medical observation with a view to providing scientific evidence for updating protocols of medical isolation. Methods Individuals related with the two SARS chains of transmission in Beijing in 2003 and a group of individuals isolated for medical observation in Haidian district of Beijing during the SARS outbreak were selected as subjects of study. Contactors with SARS patients and those with symptom development following the contacts were investigated via questionnaire. Serum samples were collected from super transmitters and tested for SARS-CoV antibody by neutralization test and enzyme linked immunosorbent assay （ELISA）. Results A total of 1 112 contactors were investigated in three surveys. Of them, 669 had a history of close contact with symptomatic SARS patients, 101 developed symptoms with a rate of 15.1%, 363 had a history of close contact with patients in their incubation period, none of whom developed symptoms （0%）. Serum samples were collected fi＇om 32 highly-exposed individuals, of whom 13 developing SARS symptoms atter contact had serum samples positive for SARS-CoV antibody. Samples collected from the asymptomatic contactors were all negative for SARS-CoV antibody. Conclusion SARS cases are infectious only during their symptomatic period and are non-infectious during the incubation period. Isolation for medical observation should be placed for individuals who are in close contact with symptomatic SARS patients. The results of our study are of decisive significance for the Ministry of Health to the definition of SARS close contactor.
文摘BACKGROUND Closed reduction and internal fixation with intramedullary nails has been widely accepted for treating intertrochanteric fractures.AIM To focus on how to avoid displacement of the lesser trochanter in unstable intertrochanteric fractures.METHODS We developed a lesser trochanteric reduction fixator for treating intertrochanteric fractures through fixing the lesser trochanter by combining the loop plate through the fixator after reduction by the reducer.Five patients with intertrochanteric fractures treated with the newly developed lesser trochanteric reduction fixator and loop plate combined with intramedullary nails,and 20 patients with intertrochanteric fractures treated with simple intramedullary nails were selected from December 2020 to March 2021.RESULTS The postoperative Harris hip score was significantly higher in patients treated with the lesser trochanteric reduction fixator than in patients treated without the lesser trochanteric reduction fixator,which indicated that this lesser trochanteric reduction fixator had a positive impact on rehabilitation of the hip joint after surgery and could significantly improve the quality of life of patients.CONCLUSION We fully realize the significance of trochanteric reduction and fixation,namely,reconstruction of structures under pressure,in the treatment of intertrochanteric fractures.As long as the general condition of patients is favorable and they are willing to undergo surgery,fixation of the main fracture end should be performed and the lesser trochanter should be reduced and fixed at the same time.
基金supported by National Natural Science Foundation of China(Nos.62027818,61874034,and 51861135105)Natural Science Foundation of Shanghai(No.18ZR1405000)Shanghai Science and Technology Innovation Program(No.19520711500).
文摘In this work,we reported a high-performance-based ultraviolet-visible(UV-VIS)photodetector based on a TiO_(2)@GaO_(x)N_(y)-Ag heterostructure.Ag particles were introduced into TiO_(2)@GaO_(x)N_(y)to enhance the visible light detection perfor-mance of the heterojunction device.At 380 nm,the responsivity and detectivity of TiO_(2)@GaO_(x)N_(y)-Ag were 0.94 A/W and 4.79×109 Jones,respectively,and they increased to 2.86 A/W and 7.96×1010 Jones at 580 nm.The rise and fall times of the response were 0.19/0.23 and 0.50/0.57 s,respectively.Uniquely,at 580 nm,the responsivity of fabricated devices is one to four orders of magnitude higher than that of the photodetectors based on TiO_(2),Ga_(2)O_(3),and other heterojunctions.The excellent optoelectronic characteristics of the TiO_(2)@GaO_(x)N_(y)-Ag heterojunction device could be mainly attributed to the synergistic effect of the type-Ⅱband structure of the metal-semiconductor-metal heterojunction and the plasmon resonance effect of Ag,which not only effectively promotes the separation of photogenerated carriers but also reduces the recombination rate.It is fur-ther illuminated by finite difference time domain method(FDTD)simulation and photoelectric measurements.The TiO_(2)@GaO_(x)N_(y)-Ag arrays with high-efficiency detection are suitable candidates for applications in energy-saving communica-tion,imaging,and sensing networks.
文摘The 20th century has witnessed three global influenza pandemics attacking mankind, namely the 1918 Spanish pandemic （H1N1 subgroup）, the 1957 Asian pandemic （H2N2 subgroup） and the 1968 Hong Kong pandemic （H3N2 subgroup）. The first pandemic swept throughout the entire world within six to nine months, which affected 400 million people, accounting for 20% of the total world population, and 40 to 50 million deaths which were more than the total deaths in World War I, resulting the worst catastrophe in the history of human infectious diseases[1]. At the moment, the world is threatened by an avian influenza pandemic and people are concerned about a potential worldwide human influenza pandemic.
基金Supported by Program of Guangxi Natural Science Foundation (2018GXNSFBA050069&2022GXNSFAA035459)the R&D Project of Guangxi Zhuang Autonomous Region Key Trauma Surgery
文摘[Objectives]To explore the active components and mechanism of Bupleurum and Asarum in the treatment of traumatic brain injury(TBI).[Methods]All the active components and potential action targets of Bupleurum and Asarum pairs were collected by online platform Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP)database and literature search.Target genes related to traumatic brain injury were obtained by Online Mendelian Inheritance in Man(OMMI),Therapeutic Target Database(TTD),PharmGKB,Genecards and Drugbank.The"drug-ingredient-target"network diagram was constructed by using Cytoscape software.Venny 2.1.0 was used to integrate the intersection targets of drug targets and disease targets,and the String platform was used to construct a target protein-protein interaction network(PPI).Topological analysis and core target screening of the constructed PPI network were performed using the"CytoNCA"plug-in in Cytoscape software.Gene Ontology(GO)annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analysis were performed on the intersection targets using the DAVID database.Finally,Autodock and Pymol software were used to simulate the binding activity of key candidate active components and core genes.[Results]25 active components were screened from Bupleurum-Asarum and 111 potential targets involved in the disease process.GO analysis and KEGG results showed that potential therapeutic targets were mainly enriched in biological processes such as inflammatory response,oxidative stress,cell membrane repair,and cytokine regulation.Network analysis and molecular docking showed that the key compounds of Bupleurum and Asarum were kaempferol and quercetin,which were well docked with the active pockets of four core genes of traumatic brain injury.[Conclusions]Bupleurum and Asarum may be involved in the regulation of inflammatory response,oxidative stress,cell membrane repair through multiple targets and multiple pathways in the treatment of traumatic brain injury.
基金supported by Postgraduate Education Reform Project of Liaoning Province(No.394)the Fund of Liaoning Provincial Department of Education(LJKMZ 20221403)the grants of the National Natural Science Foundation of China(No.21571091).
文摘The development of host-vip MOF luminescent composites has attracted considerable attention. However,it is still a challenge to reasonably design large scale conjugated polycarboxylic acids metal-organic framework (MOF) and modulate donor-acceptor interaction. Herein,a series of isostructural 3D porous lanthanide MOF [Ln_(2)(BINDI)0.5(NO_(3))(DMA)(H_(2)O)]∙DMA∙2.5H_(2)O (Ln = La (1),Ce (2),Pr (3) and Nd (4);H_(4)BINDI (N,N’-bis(5-isophthalic acid)-1,4,5,8-naphthalenediimide) were synthesized. Considering the electron-deficient performances of Ln-BINDI MOFs,D-A type composites Ln-MOFs (1—4@H_(4)TBAPy) were prepared via the incorporation of electron-rich H_(4)TBAPy (1,3,6,8-tetrakis(p-benzoic acid) pyrene),which more improved the luminescence performance of complexes 1—4 and can be used as fluorescence sensors for the detection of nitro compounds and aldehydes. High sensitivity of 1@H_(4)TBAPy towards pNBA,pNA PNP,DNP,and TNP could be achieved through hydrogen bond interactions between MOF and analytes,as well as the π-π interaction between H_(4)TBAPy and the naphthalene ring of BINDI,thus the fluorescence quenching efficiency of 1@H_(4)TBAPy was better than that of the complex 1. In addition,it is found that 1@H_(4)TBAPy has high selectivity and sensitivity to aromatic aldehyde SA,5-Mesal and HMBA. Such strategy to enhance the emission of NDI based Ln-BINDI MOFs,will open up an avenue to obtain more fluorescent MOFs for sensing.
基金supported by the National Natural Science Foundation of China(52325307,52273188,22075194,52203233)the National Key Research and Development Program of China(2022YFB4200302)+3 种基金the Department of Science and Technology of Jiangsu Province(BE2022023)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),the Collaborative Innovation Center of Suzhou Nano Science and Technology,Jiangsu Funding Program for Excellent Postdoctoral Talent(2022ZB567)the China Postdoctoral Science Foundation(2023M732533)the Key Laboratory of Polymeric Materials Design and Synthesis for Biomedical Function,Soochow University。
文摘All-solution processed organic solar cells are the ultimate aim of printable photovoltaics,but their electrical losses arising from poor contact of top electrodes greatly limit efficiency improvement.To solve the problem,a solution-processed hybrid top electrode was constructed using silver nanowires(AgNWs)as the skeleton and ZnO nanoparticles(ZnO-NPs)as the matrix.When constructing the skeleton,a spin-rinsing treatment was first used to reduce the amount of the residual insulating polyvinylpyrrolidone wrapped around the AgNWs to promote intimate contact among the AgNWs in the skeleton.Then,the ZnO-NPs matrix was deposited onto the AgNWs skeleton,bridging the AgNWs skeleton with the underlayer ZnO-NPs electron transporting layer(ETL).The underlayer ZnO-NPs ETL can also induce the growth of the ZnO-NPs matrix to minimize lattice mismatch,which creates additional transport channels from the ETL to the AgNWs skeleton for charge collection.As a result,the obtained electrode significantly enhances the electrical contact in the device,thus delivering record power conversion efficiencies of 16.04%and 14.54%for rigid and flexible all-solution processed OSCs,respectively.
基金sponsored in part by the National Natural Science Foundation of China[Grant-Nos.61902428,6210071026,62202493].
文摘The computational complexity of privacy information retrieval protocols is often linearly related to database size.When the database size is large,the efficiency of privacy information retrieval protocols is relatively low.This paper designs an effective privacy information retrieval model based on hybrid fully homomorphic encryption.The assignment method is cleverly used to replace a large number of homomorphic encryption operations.At the same time,the multiplicative homomorphic encryption scheme is first used to deal with the large-scale serialization in the search,and then the fully homomorphic encryption scheme is used to deal with the remaining simple operations.The depth of operations supported by the fully homomorphic scheme no longer depends on the size of the database,but only needs to support the single homomorphic encryption scheme to decrypt the circuit depth.Based on this hybrid homomorphic encryption retrieval model,the efficiency of homomorphic privacy information retrieval model can be greatly improved.
基金supported by the National Natural Science Foundation of China(51673138,51820105003,91633301)the Priority Academic Program Development of Jiangsu Higher Education Institutions+2 种基金the Jiangsu Provincial Natural Science Foundation(BK20160059)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(16KJB430027)the National Key Research and Development Program of China(2017YFA0207700)
文摘The performance of flexible organic solar cells(OSCs)significantly relies on the quality of transparent flexible electrode.Here,we used silver nanowires(AgNWs)with various weight ratios to dope high-conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate(PH1000)to optimize the optical and electronic properties of PH1000 film.A high-quality flexible composite electrode PET/Ag-mesh/PH1000:AgNWs-20 with smooth surface,a low sheet resistance of 6Ω/sq and a high transmittance of 86%at 550-nm wavelength was obtained by doping 20 wt%AgNWs to PH1000(PH1000:AgNWs-20).The flexible OSCs based on the PET/Ag-mesh/PH1000:AgNWs-20 electrode delivered a power conversion efficiency(PCE)of12.07%with an open circuit voltage(Voc)of 0.826 V,a short-circuit current density(Jsc)of 20.90 m A/cm2and a fill factor(FF)of69.87%,which is the highest reported PCE for the flexible indium-tin oxide(ITO)-free OSCs.This work demonstrated that the flexible composite electrodes of PET/Ag-mesh/PH1000:AgNWs are promising alternatives for the conventional PET/ITO electrode,and open a new avenue for developing high-performance flexible transparent electrode for optoelectronic devices.
基金the National Natural Science Foundation of China(No.51904352)the Scientific Research Foundation of Hunan Provincial Education Department,China(No.22A0004).
文摘Casting aluminum(Al)alloys have been widely used in the automotive industry to improve fuel economy as well as to reduce greenhouse gas(GHG)emissions in the vehicle use phase.However,the casting Al alloys used for load-bearing body and chassis components today are mostly made from primary Al with a low impurity Fe content typically less than 0.2 wt.%,owing to the requirements for high ductility and adequate fatigue strength.Primary Al is made directly from alumina which was refined from aluminum ore(bauxite),using an electrolytic process which consumes a lot of energy and produces GHG emissions that are much higher than those from steel making.The objective of this paper is to present a Unified Casting(UniCast)Al alloy concept as a sustainable materials solution for vehicle lightweighting.The UniCast alloy chemistry is intentionally designed to be more tolerant of Fe impurity.This chemistry can not only satisfy the requirements on castability,but also deliver mechanical properties needed for a variety of thin-walled and thick-walled automotive structural components that are produced by various casting processes.The UniCast alloy concept will contribute to the establishment of a closed-loop recycling system in the future as the shredded scrap obtained from the disposed end-of-life vehicles can be directly recycled back into UniCast alloy ingot with a more efficient sorting process.In addition,by setting the upper limit of Fe content in the UniCast alloy to a higher level,it will become possible to use a high fraction of post-consumer scraps to produce this alloy.To demonstrate the feasibility of this concept,an exemplary UniCast alloy chemistry has been elaborated in this article.Furthermore,challenges and future research opportunities related to the realization of UniCast alloy concept in the automotive industry are discussed.It is hoped that this article will be of great implication to industrial researchers and academicians for making concerted efforts to establish closed-loop recycling of Al castings for the automotive and other transportation industry segments.
基金supported by the National Natural Science Foundation of China(Grant Nos.51922074,22075194,51820105003,and 52203233)the National Key Research and Development Program of China(Grant No.2020YFB1506400)+4 种基金the Natural Science Foundation of the Jiangsu Higher Education Insti-tutions of China(Grant No.20KJA430010)the Tang Scholar,the Priority Academic Program Development of Jiangsu Higher Educa-tion Institutions(PAPD)the National Postdoctoral Program for Innovative Talents(Grant Nos.BX2021205 and BX20220221)project funded by China Postdoctoral Science Foundation(Grant No.2022M710102)Collaborative Innovation Center of Suzhou Nano Science and Technology.
文摘Recent advances in non-fullerene acceptors(NFAs)like Y6 have pushed the power conversion efficiencies(PCEs)of organic solar cells(OSCs)above 19%.However,the harsh fabrication conditions,such as the use of the highly volatile chloroform(CF)solvent and the thermal annealing process,are not suitable for large-area printing technologies and environmental standards.Here,a series of vip molecules,BT2O,BTO,and BT4O,are designed and synthesized with different numbers of oligo ethylene glycol(OEG)repeating units in side chains.All these vip molecules could tune the crystallization kinetics of the annealing-free host-vip active layers by inducing the self-assembly of Y6 in non-halogenated paraxylene(PX)solution.The increasing number of OEG repeating units in vip molecules could enhance the molecular assembly ability but molecular stacking steric hindrance simultaneously.Therefore,BTO with three OEG repeating units blended with PM6:PM7:Y6 delivers the highest PCE of 17.78%.Our results demonstrate controlling the crystallization kinetics via delicate side-chain engineering of vip molecules is an effective way to achieve efficient OSCs in non-halogenated solution.
基金This work is supported by the National Natural Science Foundation of China(Nos.62027818,51861135105,61874034,and 11974320)the National Key R&D Program of China(No.2021YFB3202500)the International Science and Technology Cooperation Program of Shanghai Science and Technology Innovation Action Plan(No.21520713300)。
文摘Inorganic micro light-emitting diodes(micro-LEDs)based on II-V compound semiconductors have been widely studied for self-emissive displays.From chips to applications,integration technology plays an indispensable role in micro-LED displays.
基金supported by the National Natural Science Foundation of China (Nos.62027818,61874034,12175298,and 51861135105)Natural Science Foundation of Shanghai (Nos.18ZR1405000 and 20ZR1464100)+1 种基金the National Natural Science Foundation of China (No.51972319)the Science and Technology Commission of Shanghai Municipality (No.19520744400).
文摘Deep-ultraviolet(DUV)phototransistors have shown great potential applications in UV imaging,artificial intelligence,and wearable optoelectronics.Among a large number of wide bandgap semiconductors,the quasi-two-dimensionalβ-Ga_(2)O_(3) is considered as an ideal candidate for DUV photodetector applications.Herein,we report a high responsivity(R)and fully flexible Ta-dopedβ-Ga_(2)O_(3) DUV phototransistor which exhibits outstanding optoelectrical properties with a high R of 1.32×10^(6) A/W,a large detectivity of 5.68×10^(14) Jones,a great photo-to-dark current ratio of 1.10×10^(10)%,a high external quantum efficiency of 6.60×10^(8)%,and an ultra-fast response time of~3.50 ms.Besides,the flexible Ta-dopedβ-Ga_(2)O_(3) device also displays high reliability and mechanical flexibility that can sustain well after over 1×10^(4) bending cycles.Moreover,high-contrast imaging of UV light was obtained on the flexible DUV detector arrays,which can be efficiently trained and recognized by an artificial neural network.Our findings offer a perspective to develop wearable optoelectronics and UV imaging based on high-performance flexibleβ-Ga_(2)O_(3) DUV phototransistors,providing an inspiration for the future work in artificial intelligence and bionic robot fields.
基金synchrotron PXRD experiment was conducted at the Powder Diffraction beamline,ANSTO Australian Synchrotron under proposal Nos.AS211/PD/16842 and AS221/PD/17948G.Z.acknowledges the funding from the National Natural Science Foundation of China(No.51904352)Scientific Research Foundation of Hunan Provincial Education Department,China(No.22A0004)。
文摘Thermal-mechanical processing of magnesium-based materials is an effective method to tailor the hydrogen storage performance.In this study,Mg-Ni-Gd-Y-Zn-Cu alloys were prepared by Direct Chill(DC)casting,with and without extrusion process.The influences of microstructure evolution,introduced by DC casting and thermal-mechanical processing,on the hydrogen storage performance of Mg-Ni-Gd-Y-ZnCu alloys were comprehensively explored,using analytical electron microscopy and in-situ synchrotron powder X-ray diffraction.The result shows that the extruded alloy yields higher hydrogen absorption capacity and faster hydrogen ab/desorption kinetics.As subjected to extrusion processing,theα-Mg grains in the microstructure were significantly refined and a large number of 14H type long-period stacking ordered(LPSO)phases appeared on theα-Mg matrix.After activation,there were more nanosized Gd hydride/Mg2Ni intermetallics and finer chips.These modifications synergistically enhance the hydrogen storage properties.The findings have implications for the alloy design and manufacturing of magnesiumbased hydrogen storage materials with the advantages of rapid mass production and anti-oxidation.
基金supported by the National Natural Science Foundation of China(Nos.62027818,61874034,51861135105,and 51972319)International Science and Technology Cooperation Program of Shanghai Science and Technology Innovation Action Plan(No.21520713300)Science and Technology Commission of Shanghai Municipality(No.19520744400).
文摘Deep ultraviolet(DUV)phototransistors are key integral of optoelectronics bearing a wide spectrum of applications in flame sensor,military detector,oil spill detection,biological sensor,and artificial intelligence fields.In order to further improve the responsivity of UV photodetectors based onβ-Ga_(2)O_(3),in present work,high-performanceβ-Ga_(2)O_(3) phototransistors with local back-gate structure were experimentally demonstrated.The phototransistor shows excellent DUV photoelectrical performance with a high responsivity of 1.01×107 A/W,a high external quantum efficiency of 5.02×109%,a sensitive detectivity of 2.98×1015 Jones,and a fast rise time of 0.2 s under 250 nm illumination.Besides,first-principles calculations reveal the decent stability ofβGa_(2)O_(3) nanosheet against oxidation and humidity without significant performance degradations.Additionally,the hexagonal boron nitride(h-BN)/β-Ga_(2)O_(3) phototransistor can behave as a photonic synapse with ultralow power consumption of~9.6 fJ per spike,which shows its potential for neuromorphic computing tasks such as facial recognition.Thisβ-Ga_(2)O_(3) phototransistor will provide a perspective for the next generation optoelectrical systems.
基金This research was supported by the National Natural Science Foundation of China （Nos. 21635002, U1505221, and 21705023）, the Program for Changjiang Scholars and Innovative Research Team in University （No. IRT15R11）, and the Independent Research Project of State Key Laboratory of Photocatalysis on Energy and Environment （No. 2014B02）.
基金supported by the National Natural Science Foundation of China(Nos.62027818,51861135105,61874034,and 11974320)the National Key Research and Development Program of China(No.2021YFB3202500)International Science and Technology Cooperation Program of Shanghai Science and Technology Innovation Action Plan(No.21520713300).
文摘The unipolar photocurrent in conventional photodiodes(PDs)based on photovoltaic effect limits the output modes and potential versatility of these devices in photodetection.Bipolar photodiodes with photocurrent switching are emerging as a promising solution for obtaining photoelectric devices with unique and attractive functions,such as optical logic operation.Here,we design an all-solid-state chip-scale ultraviolet(UV)PD based on a hybrid GaN heterojunction with engineered bipolar polarized electric field.By introducing the polarization-induced photocurrent switching effect,the photocurrent direction can be switched in response to the wavelength of incident light at 0 V bias.In particular,the photocurrent direction exhibits negative when the irradiation wavelength is less than 315 nm,but positive when the wavelength is longer than 315 nm.The device shows a responsivity of up to−6.7 mA/W at 300 nm and 5.3 mA/W at 340 nm,respectively.In particular,three special logic gates in response to different dual UV light inputs are demonstrated via a single bipolar PD,which may be beneficial for future multifunctional UV photonic integrated devices and systems.
