The T-gate stem height of In Al As/In Ga As In P-based high electron mobility transistor(HEMT) is increased from165 nm to 250 nm. The influences of increasing the gate stem height on the direct current(DC) and radio f...The T-gate stem height of In Al As/In Ga As In P-based high electron mobility transistor(HEMT) is increased from165 nm to 250 nm. The influences of increasing the gate stem height on the direct current(DC) and radio frequency(RF)performances of device are investigated. A 120-nm-long gate, 250-nm-high gate stem device exhibits a higher threshold voltage(Vth) of 60 m V than a 120-nm-long gate devices with a short gate stem, caused by more Pt distributions on the gate foot edges of the high Ti/Pt/Au gate. The Pt distribution in Schottky contact metal is found to increase with the gate stem height or the gate length increasing, and thus enhancing the Schottky barrier height and expanding the gate length,which can be due to the increased internal tensile stress of Pt. The more Pt distributions for the high gate stem device also lead to more obvious Pt sinking, which reduces the distance between the gate and the In Ga As channel so that the transconductance(gm) of the high gate stem device is 70 m S/mm larger than that of the short stem device. As for the RF performances,the gate extrinsic parasitic capacitance decreases and the intrinsic transconductance increases after the gate stem height has been increased, so the RF performances of device are obviously improved. The high gate stem device yields a maximum ft of 270 GHz and fmax of 460 GHz, while the short gate stem device has a maximum ft of 240 GHz and the fmax of 370 GHz.展开更多
Heterogeneous integrated InP high electron mobility transistors(HEMTs)on quartz wafers are fabricated successfully by using a reverse-grown InP epitaxial structure and benzocyclobutene(BCB)bonding technology.The chann...Heterogeneous integrated InP high electron mobility transistors(HEMTs)on quartz wafers are fabricated successfully by using a reverse-grown InP epitaxial structure and benzocyclobutene(BCB)bonding technology.The channel of the new device is In_(0.7)Ga_(0.3)As,and the gate length is 100 nm.A maximum extrinsic transconductance gm,max of 855.5 mS/mm and a maximum drain current of 536.5 mA/mm are obtained.The current gain cutoff frequency is as high as 262 GHz and the maximum oscillation frequency reaches 288 GHz.In addition,a small signal equivalent circuit model of heterogeneous integration of InP HEMTs on quartz wafer is built to characterize device performance.展开更多
Dear Editor,Akabane disease is an arthropod-borne viral disease caused by the Akabane virus(AKAV)that can affect cattle,sheep,and goats.Inapparent infections in adults can lead months later to abortions,stillbirths,co...Dear Editor,Akabane disease is an arthropod-borne viral disease caused by the Akabane virus(AKAV)that can affect cattle,sheep,and goats.Inapparent infections in adults can lead months later to abortions,stillbirths,congenital defects,and death in newborns(Kurogi et al.,1976).Wild ruminants can also be affected,but abnormalities of the offspring in these species have not been reported.One report suggests that this virus can also cause clinical signs in pigs(Yanase et al.,2018).展开更多
The method of 2-D travel time inversion, which can be applied to determining 2-D velocity structure and interfaces simultaneously, is used in this paper to reprocess the data of Paiku Co-Pumoyingcuo seismic profile ac...The method of 2-D travel time inversion, which can be applied to determining 2-D velocity structure and interfaces simultaneously, is used in this paper to reprocess the data of Paiku Co-Pumoyingcuo seismic profile across the Nyima-Tingri rift and Shenzha-Dinggye rift. P-wave velocity structure and interfaces beneath the profile are obtained. The interfaces in the crust near Tingri and Dinggye which are located on rifts have a tendency to uplift, and velocities of middle and lower crusts are high. Low velocity layer in upper crust has an offset. Compared with the distribution of the earthquakes in this region, it is speculated that normal faults near Tingri and Dinggye extend to the upper mantle. Apparently it is affected by deep material： the uplift of mantle causes partial melting in the crust, thus the thickness of crust in this area becomes thin, and tension failures occur in this region easily. On the basis of the characteristics of the earthquakes＇ distribution and the structures of the crustal velocity and interfaces, materials from the mantle still uplifts and the failures are still active.展开更多
With the widespread utilization of indium-phosphide-based high-electron-mobility transistors(InP HEMTs)in the millimeter-wave(mmW)band,the distributed and high-frequency parasitic coupling behavior of the device is pa...With the widespread utilization of indium-phosphide-based high-electron-mobility transistors(InP HEMTs)in the millimeter-wave(mmW)band,the distributed and high-frequency parasitic coupling behavior of the device is particularly prominent.We present an InP HEMT extrinsic parasitic equivalent circuit,in which the conductance between the device electrodes and a new gate-drain mutual inductance term L_(mgd)are taken into account for the high-frequency magnetic field coupling between device electrodes.Based on the suggested parasitic equivalent circuit,through HFSS and advanced design system(ADS)co-simulation,the equivalent circuit parameters are directly extracted in the multi-step system.The HFSS simulation prediction,measurement data,and modeled frequency response are compared with each other to verify the feasibility of the extraction method and the accuracy of the equivalent circuit.The proposed model demonstrates the distributed and radio-frequency behavior of the device and solves the problem that the equivalent circuit parameters of the conventional InP HEMTs device are limited by the device model and inaccurate at high frequencies when being extracted.展开更多
Iron-based superconductor family FeX(X=S,Se,Te)has been one of the research foci in physics and material science due to their record-breaking superconducting temperature(FeSe film)and rich physical phenomena.Recently,...Iron-based superconductor family FeX(X=S,Se,Te)has been one of the research foci in physics and material science due to their record-breaking superconducting temperature(FeSe film)and rich physical phenomena.Recently,FeS,the least studied Fe X compound(due to the difficulty in synthesizing high quality macroscopic crystals)attracted much attention because of its puzzling superconducting pairing symmetry.In this work,combining scanning tunneling microscopy and angle resolved photoemission spectroscopy(ARPES)with sub-micron spatial resolution,we investigate the intrinsic electronic structures of superconducting FeS from individual single crystalline domains.Unlike FeTe or FeSe,FeS remains identical tetragonal structure from room temperature down to 5 K,and the band structures observed can be well reproduced by our ab-initio calculations.Remarkably,mixed with the 1×1 tetragonal metallic phase,we also observe the coexistence of √5×√5 reconstructed insulating phase in the crystal,which not only helps explain the unusual properties of FeS,but also demonstrates the importance of using spatially resolved experimental tools in the study of this compound.展开更多
Propagation properties of bright and dark incoherent beams are numerically studied in photovoltaic-photorefractive crystal by using coherent density approach for the first time. Numerical simulations not only exhibit ...Propagation properties of bright and dark incoherent beams are numerically studied in photovoltaic-photorefractive crystal by using coherent density approach for the first time. Numerical simulations not only exhibit that bright incoherent photovoltaic quasi-soliton, grey-like incoherent photovoltaic soliton, incoherent soliton doublet and triplet can be established under proper conditions, but also display that the spatial coherence properties of these incoherent beams can be significantly affected during propagation by the photovoltaic field.展开更多
A new star-shaped molecule StOF-Br_3 containing oligofluorenes and halogen atoms(Bromine) has been synthesized and studied by Scanning Tunneling Microscopy(STM) at the highly oriented pyrolytic graphite(HOPG) surface....A new star-shaped molecule StOF-Br_3 containing oligofluorenes and halogen atoms(Bromine) has been synthesized and studied by Scanning Tunneling Microscopy(STM) at the highly oriented pyrolytic graphite(HOPG) surface.We have obtained the high-resolution self-assembled STM images,from which the highly ordered and closely packed non-porous arrangements of the StOF-Br_3 molecular selfassemblies at the heptanoic acid/HOPG surface could be observed.The molecular models and selfassembled StOF-Br_3 architectures have been given in the following text.Besides,we have also figured out the surface free energy by the density functional theory(DFT) calculation,which proved that the halogen...halogen interaction was strong enough to stabilize the ordered molecular self-assemblies.This work verifies the existence of bromine...bromine interactions,and meanwhile provides a kind of effective approach for quickly building ordered molecular nanoarchitectures with large areas and different geometries.展开更多
Mariculture exerts a direct influence on planktonic eukaryotic microorganisms protists.Previous studies have focused on phytoplankton,while the heterotrophic and parasitic protistan groups are unknown.Currently,in Mup...Mariculture exerts a direct influence on planktonic eukaryotic microorganisms protists.Previous studies have focused on phytoplankton,while the heterotrophic and parasitic protistan groups are unknown.Currently,in Muping Marine Ranch(MR)which is along the littoral zone of northern Yellow Sea of China,environmental DNA methods were employed to investigate the diversity and seasonal dynamics of near shore planktonic protists in response to mariculture.Through an integrated analysis of functional groups and a comparison to adjacent sea areas,we found a dominance of harmful algae blooms(HAB)species nearshore MR,and a significant reduction in the diversity of planktonic protists including photosynthetic,heterotrophic and parasitic groups.High nutrient and low salinity were suggested to drive the dominance of HAB species nearshore MR,which in return might inhibit predators,saprophytes and algal parasites.Our investigations revealed an Olisthodiscus luteus outbreak in spring,as well as significant seasonal variations in the planktonic protist community,which might be caused by the changes of temperature.The offshore hypoxia reduced the abundance of phytoplankton but increased mixotrophs and animal parasites of the protistan community nearshore MR.This study highlights the influence of mariculture on the overall community function of planktonic protists,and is helpful to assess the mariculture's impact on water health.展开更多
In this study,large-scale Te-doped polycrystalline SnSe nanopowders were synthesized by a facile hydrothermal approach and the effect of Te doping on the thermoelectric properties of SnSe was fully investigated.It is ...In this study,large-scale Te-doped polycrystalline SnSe nanopowders were synthesized by a facile hydrothermal approach and the effect of Te doping on the thermoelectric properties of SnSe was fully investigated.It is found that the carrier concentration increases due to the reduction of band gap by alloying with Te,which contributes to significant enhancement of electrical conductivity especially at room temperature.Combined with the moderated Seebeck coefficient,a high power factor of 4.59μW cm 1 K 2 is obtained at 773 K.Furthermore,the lattice the rmal conductivity is greatly reduced upon Te substitution owing to the atomic point defect scattering.Benefiting from the synergistically optimized both electrical-and thermal-transport properties by Te-doping,thermoelectric performance of polycrystalline SnSe is enhanced in the whole temperature range with a maximum ZT of-0.79 at a relatively low temperature(773 K) for SnSe0.85Te0.15.This study provides a low-cost and simple lowtemperature method to mass production of SnSe with high thermoelectric performance for practical applications.展开更多
Bionic micro/nanomotor systems,which combine biomimetic design with the motion performance,have shown great potential in many fields.However,so far,it remains a challenge to design and fabricate biomimetic micro/nanom...Bionic micro/nanomotor systems,which combine biomimetic design with the motion performance,have shown great potential in many fields.However,so far,it remains a challenge to design and fabricate biomimetic micro/nanomotors with high flexibility to perform complex tasks in complicated and changeable environments.In this work,inspired by the suckerfishes(vip)-shark(host)motion behavior,we designed and prepared a kind of intelligent two-stage micro@nanomotor with weak acid-triggered release of nanomotor.When the suckerfishes,who clinged to the surface of large fish or the bottom of boat and marched with them,reached bait-rich waters,they detached from the host to engage in foraging behavior.Inspired by the suckerfishes-shark system and the coordinated bond interaction,a large amount of Janus Au-Pt nanomotors with hydrogen peroxide(H_(2)O_(2))-driven capacity,analogous to suckerfishes,were attached onto immovable yolk-shell structured polydopamine-mesoporous silica(PDA-MS)micromotor as the host to create two-stage PDA-MS@Au-Pt micro@nanomotor.PDA-MS@Au-Pt micro@nanomotor moved directionally by self-thermophoresis under the propulsion of near infrared ray(NIR)light with low power density.When the PDA-MS@Au-Pt entered into the weak acidic environment formed by a low concentration of H_(2)O_(2),most small Au-Pt nanomotors were detached from the surface of PDA-MS due to the weak acidic sensitivity of the coordinated bond,and then performed self-diffusiophoresis in the environment containing a low concentration of H_(2)O_(2) as a chemical fuel.This bionic intelligent system,which consists of a large-sized micromotor and lots of small-sized nanomotors,should provide a new insight for active two-stage cargo delivery.展开更多
Manufactured nanomaterials with unique properties have been extensively applied in various indus-trial,agricultural or medical fields.However,some of the properties have been identified to be closely related to nanoma...Manufactured nanomaterials with unique properties have been extensively applied in various indus-trial,agricultural or medical fields.However,some of the properties have been identified to be closely related to nanomaterial toxicity.The"nano-paradox"has aroused concerns over the use and develop-ment of nanotechnology,which makes it difficult for regulatory agencies to regulate nanomaterials.The key to fulfilling proper nanomaterial regulation lies in the adequate understanding of the impact of nanomaterial properties on nano-bio interactions.To this end,we start the present work with a brief intro-duction to nano-bio interactions at different levels.Based on that,how key toxicity-associated properties of manufactured nanomaterials(i.e.,size,shape,chemical composition,surface properties,biocorona formation,agglomeration and/or aggregation state,and biodegradability)impact their toxicokinetics,cel-lular uptake,trafficking and responses,and toxicity mechanisms is deeply explored.Moreover,advanced analytical methods for studying nano-bio interactions are introduced.Furthermore,the current reg-ulatory and legislative frameworks for nanomaterial-containing products in different regions and/or countries are presented.Finally,we propose several challenges facing the nanotoxicology field and their possible solutions to shed light on the safety evaluation of nanomaterials.展开更多
N-type Se&Lu-codoped Bi2Te3 nanopowders were prepared by hydrothermal method and sintered by spark plasma sintering technology to form dense samples.By further doping Se element into Lu-doped Bi2Te3 samples,the th...N-type Se&Lu-codoped Bi2Te3 nanopowders were prepared by hydrothermal method and sintered by spark plasma sintering technology to form dense samples.By further doping Se element into Lu-doped Bi2Te3 samples,the thickness of the nanosheets has the tendency to become thinner.The electrical conductivity of Lu0.1Bi1.9Te3−xSex material is reduced with the increasing Se content due to the reduced carrier concentration,while the Seeback coefficient values are enhanced.The lattice thermal conductivity of the Lu0.1Bi1.9Te3−xSex is greatly reduced due to the introduced point defects and atomic mass fluctuation.Finally,the Lu0.1Bi1.9Te2.7Se0.3 sample obtained a maximum ZT value of 0.85 at 420 K.This study provides a low-cost and simple low-temperature method to mass production of Se&Lu-codoped Bi2Te3 with high thermoelectric performance for practical applications.展开更多
The ability to control surface wettability and liquid spreading on textured surfaces is of interest for extensive applications.Soft materials have prominent advantages for producing the smart coatings with multiple fu...The ability to control surface wettability and liquid spreading on textured surfaces is of interest for extensive applications.Soft materials have prominent advantages for producing the smart coatings with multiple functions for strain sensing.Here,we report a simple method to prepare flexible hydrophobic smart coatings using graphene-polymer films.Arrays of individual patterns in the films were created by laser engraving and controlled the contact angle of small drops by pinning the contact lines in a horizontal tensile range of 0-200%.By means of experiments and model,we demonstrate that the ductility of drops is relied on the height-to-spacing ratio of the individual pattern and the intrinsic contact angle.Moreover,the change of drop size was utilized to measure the applied strain and liquid viscosity,enabling a strain sensitivity as high as 1068μm2/%.The proposed laser-etched stretchable graphene-polymer composite has potential applications in DNA microarrays,biological assays,soft robots,and so on.展开更多
Rapidly spreading coronavirus disease 2019(COVID-19)is currently affecting the world.Specifically,cytokine storms are a key feature in a substantial num ber of COVID-19 patients,1 and studies from our group and others...Rapidly spreading coronavirus disease 2019(COVID-19)is currently affecting the world.Specifically,cytokine storms are a key feature in a substantial num ber of COVID-19 patients,1 and studies from our group and others suggest that the IL-6/IL-6R cascade plays a dom inant role in symptom-correlated cytokine storms.展开更多
In order to select suitable sites for farmland consolidation projects,correlation analysis and evolutionary algorithms were used to optimize the evaluation of ecological,social and economic factors,avoiding subjective...In order to select suitable sites for farmland consolidation projects,correlation analysis and evolutionary algorithms were used to optimize the evaluation of ecological,social and economic factors,avoiding subjective selection and ignorance of spatial relationships among land attributes.Multi-objective Genetic Algorithms(MOGA)were applied to select the best sites from the perspective of spatial relationship and land attribute evaluation.With carefully defined restrictions and variables,multi-objective optimization is able to select several suitable sites for farmland consolidation projects.The results from a case study in Yangshan,Guangdong of China showed that the selected sites were on the central and southern Yangshan with expected flat terrain and abundant water resources.An empirical experiment also demonstrated that the proposed method is able to provide well selected sites for land consolidation projects.展开更多
The traditional design of the catalytic combustion gas sensor in Micro ElectroMechanical Systems (MEMS) micro-hotplate employs a Pt resistive track as the micro-heater. The realized structure and fabrication are the k...The traditional design of the catalytic combustion gas sensor in Micro ElectroMechanical Systems (MEMS) micro-hotplate employs a Pt resistive track as the micro-heater. The realized structure and fabrication are the key elements of the micro-hotplate. Directly fabrication of micro-pellsitor catalyst is very difficult because of the small dimensions of the active area. In this paper, a novel micro-pellistor was designed by combining micro fabrication technique and nano technology. The supporting beams and micro-hotplate of the micro-pellistor were made of nonoporous alumina film. The active area of the designed and fabricated micro-pellistors ranges from 200×200 μm2 to 450×300 μm2. The micro- pellistor was heated by platinum thin film heater and the Pd catalyst was deposited by dipping the PdCl2 solution on the detecting element. The lowest power consumption is 50 mW at 500 °C and the maximum temperature can reach 900 °C before rupture. The response of the devices to methane is also tested. The new design provides a new way to fabricate micro-pellistor.展开更多
RNA editing was first discovered in mitochondrial RNA molecular. However, whether adenosine-toinosine(A-to-I) RNA editing has functions in nuclear genes involved in mitochondria remains elusive.Here, we retrieved 707,...RNA editing was first discovered in mitochondrial RNA molecular. However, whether adenosine-toinosine(A-to-I) RNA editing has functions in nuclear genes involved in mitochondria remains elusive.Here, we retrieved 707,246 A-to-I RNA editing sites in Macaca mulatta leveraging massive transcriptomes of 30 different tissues and genomes of nine tissues, together with the reported data, and found that A-to-I RNA editing occurred frequently in nuclear genes that have functions in mitochondria. The mitochondrial structure, the level of ATP production, and the expression of some key genes involved in mitochondrial function were dysregulated after knocking down the expression of ADAR1 and ADAR2, the key genes encoding the enzyme responsible for RNA editing. When investigating dynamic changes of RNA editing during brain development, an amino-acid-changing RNA editing site(I234/V) in MFN1, a mediator of mitochondrial fusion, was identified to be significantly correlated with age, and could influence the function of MFN1. When studying transcriptomes of brain disorder, we found that dysregulated RNA editing sites in autism were also enriched within genes having mitochondrial functions. These data indicated that RNA editing had a significant function in mitochondria via their influence on nuclear genes.展开更多
The interaction of colloidal gold with Taq DNA polymerase （Taq） was investigated in this study. Taq-gold conjugate was formed by adding the enzyme to the colloidal gold solution, as evidenced by UV-Vis spectroscopy,...The interaction of colloidal gold with Taq DNA polymerase （Taq） was investigated in this study. Taq-gold conjugate was formed by adding the enzyme to the colloidal gold solution, as evidenced by UV-Vis spectroscopy, X-ray photoelectron spectroscopy, and photon cross correlation spectroscopy measurements. The conjugate was further characterized by transmission electron microscopy. It was found that the Taq-gold conjugate particles were still spherical and well-dispersed. The influence of gold nanoparticles on the bioactivity of Taq was studied by analyzing the yield of the polymerase chain reaction amplification. Results indicated that the enzymatic activity of Taq decreased after interaction with the colloidal gold.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61434006)。
文摘The T-gate stem height of In Al As/In Ga As In P-based high electron mobility transistor(HEMT) is increased from165 nm to 250 nm. The influences of increasing the gate stem height on the direct current(DC) and radio frequency(RF)performances of device are investigated. A 120-nm-long gate, 250-nm-high gate stem device exhibits a higher threshold voltage(Vth) of 60 m V than a 120-nm-long gate devices with a short gate stem, caused by more Pt distributions on the gate foot edges of the high Ti/Pt/Au gate. The Pt distribution in Schottky contact metal is found to increase with the gate stem height or the gate length increasing, and thus enhancing the Schottky barrier height and expanding the gate length,which can be due to the increased internal tensile stress of Pt. The more Pt distributions for the high gate stem device also lead to more obvious Pt sinking, which reduces the distance between the gate and the In Ga As channel so that the transconductance(gm) of the high gate stem device is 70 m S/mm larger than that of the short stem device. As for the RF performances,the gate extrinsic parasitic capacitance decreases and the intrinsic transconductance increases after the gate stem height has been increased, so the RF performances of device are obviously improved. The high gate stem device yields a maximum ft of 270 GHz and fmax of 460 GHz, while the short gate stem device has a maximum ft of 240 GHz and the fmax of 370 GHz.
基金the National Natural Science Foundation of China(Grant No.61434006).
文摘Heterogeneous integrated InP high electron mobility transistors(HEMTs)on quartz wafers are fabricated successfully by using a reverse-grown InP epitaxial structure and benzocyclobutene(BCB)bonding technology.The channel of the new device is In_(0.7)Ga_(0.3)As,and the gate length is 100 nm.A maximum extrinsic transconductance gm,max of 855.5 mS/mm and a maximum drain current of 536.5 mA/mm are obtained.The current gain cutoff frequency is as high as 262 GHz and the maximum oscillation frequency reaches 288 GHz.In addition,a small signal equivalent circuit model of heterogeneous integration of InP HEMTs on quartz wafer is built to characterize device performance.
文摘Dear Editor,Akabane disease is an arthropod-borne viral disease caused by the Akabane virus(AKAV)that can affect cattle,sheep,and goats.Inapparent infections in adults can lead months later to abortions,stillbirths,congenital defects,and death in newborns(Kurogi et al.,1976).Wild ruminants can also be affected,but abnormalities of the offspring in these species have not been reported.One report suggests that this virus can also cause clinical signs in pigs(Yanase et al.,2018).
基金supported by the National Natural Science Foundation of China (No. 40674052)
文摘The method of 2-D travel time inversion, which can be applied to determining 2-D velocity structure and interfaces simultaneously, is used in this paper to reprocess the data of Paiku Co-Pumoyingcuo seismic profile across the Nyima-Tingri rift and Shenzha-Dinggye rift. P-wave velocity structure and interfaces beneath the profile are obtained. The interfaces in the crust near Tingri and Dinggye which are located on rifts have a tendency to uplift, and velocities of middle and lower crusts are high. Low velocity layer in upper crust has an offset. Compared with the distribution of the earthquakes in this region, it is speculated that normal faults near Tingri and Dinggye extend to the upper mantle. Apparently it is affected by deep material： the uplift of mantle causes partial melting in the crust, thus the thickness of crust in this area becomes thin, and tension failures occur in this region easily. On the basis of the characteristics of the earthquakes＇ distribution and the structures of the crustal velocity and interfaces, materials from the mantle still uplifts and the failures are still active.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61434006 and 61704189)the Fund from the Youth Innovation Promotion Association of the Chinese Academy of Sciences。
文摘With the widespread utilization of indium-phosphide-based high-electron-mobility transistors(InP HEMTs)in the millimeter-wave(mmW)band,the distributed and high-frequency parasitic coupling behavior of the device is particularly prominent.We present an InP HEMT extrinsic parasitic equivalent circuit,in which the conductance between the device electrodes and a new gate-drain mutual inductance term L_(mgd)are taken into account for the high-frequency magnetic field coupling between device electrodes.Based on the suggested parasitic equivalent circuit,through HFSS and advanced design system(ADS)co-simulation,the equivalent circuit parameters are directly extracted in the multi-step system.The HFSS simulation prediction,measurement data,and modeled frequency response are compared with each other to verify the feasibility of the extraction method and the accuracy of the equivalent circuit.The proposed model demonstrates the distributed and radio-frequency behavior of the device and solves the problem that the equivalent circuit parameters of the conventional InP HEMTs device are limited by the device model and inaccurate at high frequencies when being extracted.
基金Project supported by CAS-Shanghai Science Research Center,China(Grant No.CAS-SSRC-YH-2015-01)the National Key R&D Program of China(Grant No.2017YFA0305400)+4 种基金the National Natural Science Foundation of China(Grant Nos.11674229,11227902,and 11604207)the EPSRC Platform Grant(Grant No.EP/M020517/1)Hefei Science Center,Chinese Academy of Sciences(Grant No.2015HSC-UE013)Science and Technology Commission of Shanghai Municipality,China(Grant No.14520722100)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB04040200)。
文摘Iron-based superconductor family FeX(X=S,Se,Te)has been one of the research foci in physics and material science due to their record-breaking superconducting temperature(FeSe film)and rich physical phenomena.Recently,FeS,the least studied Fe X compound(due to the difficulty in synthesizing high quality macroscopic crystals)attracted much attention because of its puzzling superconducting pairing symmetry.In this work,combining scanning tunneling microscopy and angle resolved photoemission spectroscopy(ARPES)with sub-micron spatial resolution,we investigate the intrinsic electronic structures of superconducting FeS from individual single crystalline domains.Unlike FeTe or FeSe,FeS remains identical tetragonal structure from room temperature down to 5 K,and the band structures observed can be well reproduced by our ab-initio calculations.Remarkably,mixed with the 1×1 tetragonal metallic phase,we also observe the coexistence of √5×√5 reconstructed insulating phase in the crystal,which not only helps explain the unusual properties of FeS,but also demonstrates the importance of using spatially resolved experimental tools in the study of this compound.
基金Supported by the Key Project of the National Natural Science Foundation of China under Grant No 10674176.
文摘Propagation properties of bright and dark incoherent beams are numerically studied in photovoltaic-photorefractive crystal by using coherent density approach for the first time. Numerical simulations not only exhibit that bright incoherent photovoltaic quasi-soliton, grey-like incoherent photovoltaic soliton, incoherent soliton doublet and triplet can be established under proper conditions, but also display that the spatial coherence properties of these incoherent beams can be significantly affected during propagation by the photovoltaic field.
基金The financial supports from the National Natural Science Foundation of China(NSFC,Nos.21773041 and 21327805)the National Basic Research Program of China(No.2016YFA0200700)。
文摘A new star-shaped molecule StOF-Br_3 containing oligofluorenes and halogen atoms(Bromine) has been synthesized and studied by Scanning Tunneling Microscopy(STM) at the highly oriented pyrolytic graphite(HOPG) surface.We have obtained the high-resolution self-assembled STM images,from which the highly ordered and closely packed non-porous arrangements of the StOF-Br_3 molecular selfassemblies at the heptanoic acid/HOPG surface could be observed.The molecular models and selfassembled StOF-Br_3 architectures have been given in the following text.Besides,we have also figured out the surface free energy by the density functional theory(DFT) calculation,which proved that the halogen...halogen interaction was strong enough to stabilize the ordered molecular self-assemblies.This work verifies the existence of bromine...bromine interactions,and meanwhile provides a kind of effective approach for quickly building ordered molecular nanoarchitectures with large areas and different geometries.
基金supported by the National Natural Science Foundation of China(Nos.42176163,31970398,and 32370488)the Youth Innovation Promotion Association,CAS(Nos.2019216 and 2022211)。
文摘Mariculture exerts a direct influence on planktonic eukaryotic microorganisms protists.Previous studies have focused on phytoplankton,while the heterotrophic and parasitic protistan groups are unknown.Currently,in Muping Marine Ranch(MR)which is along the littoral zone of northern Yellow Sea of China,environmental DNA methods were employed to investigate the diversity and seasonal dynamics of near shore planktonic protists in response to mariculture.Through an integrated analysis of functional groups and a comparison to adjacent sea areas,we found a dominance of harmful algae blooms(HAB)species nearshore MR,and a significant reduction in the diversity of planktonic protists including photosynthetic,heterotrophic and parasitic groups.High nutrient and low salinity were suggested to drive the dominance of HAB species nearshore MR,which in return might inhibit predators,saprophytes and algal parasites.Our investigations revealed an Olisthodiscus luteus outbreak in spring,as well as significant seasonal variations in the planktonic protist community,which might be caused by the changes of temperature.The offshore hypoxia reduced the abundance of phytoplankton but increased mixotrophs and animal parasites of the protistan community nearshore MR.This study highlights the influence of mariculture on the overall community function of planktonic protists,and is helpful to assess the mariculture's impact on water health.
基金funded by the Fundamental Research Funds for the Central Universities (No.2232020A-02)National Natural Science Foundation of China (Nos.51774096,51871053,51902333)+3 种基金Shanghai Committee of Science and Technology (No.18JC1411200)Program for Innovative Research Team in University of Ministry of Education of China (No.IRT16R13)financial support sponsored by Shanghai Sailing Program (No. 19YF1454000)Key Research Program of Frontier Sciences,CAS (No.ZDBS-LY-JSC037)。
文摘In this study,large-scale Te-doped polycrystalline SnSe nanopowders were synthesized by a facile hydrothermal approach and the effect of Te doping on the thermoelectric properties of SnSe was fully investigated.It is found that the carrier concentration increases due to the reduction of band gap by alloying with Te,which contributes to significant enhancement of electrical conductivity especially at room temperature.Combined with the moderated Seebeck coefficient,a high power factor of 4.59μW cm 1 K 2 is obtained at 773 K.Furthermore,the lattice the rmal conductivity is greatly reduced upon Te substitution owing to the atomic point defect scattering.Benefiting from the synergistically optimized both electrical-and thermal-transport properties by Te-doping,thermoelectric performance of polycrystalline SnSe is enhanced in the whole temperature range with a maximum ZT of-0.79 at a relatively low temperature(773 K) for SnSe0.85Te0.15.This study provides a low-cost and simple lowtemperature method to mass production of SnSe with high thermoelectric performance for practical applications.
基金supported by Fundamental Research Funds for the Central Universities(No.FRF-BR-23-02B)China Postdoctoral Science Foundation(No.2023M731408)+2 种基金Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2023ZB640)Jiangsu Province Capability Improvement Project through Science,technology and Education(Jiangsu Provincial Medical Key Discipline,ZDXK202222)Natural Science Foundation of Jiangsu Province(No.BK20230731).
文摘Bionic micro/nanomotor systems,which combine biomimetic design with the motion performance,have shown great potential in many fields.However,so far,it remains a challenge to design and fabricate biomimetic micro/nanomotors with high flexibility to perform complex tasks in complicated and changeable environments.In this work,inspired by the suckerfishes(vip)-shark(host)motion behavior,we designed and prepared a kind of intelligent two-stage micro@nanomotor with weak acid-triggered release of nanomotor.When the suckerfishes,who clinged to the surface of large fish or the bottom of boat and marched with them,reached bait-rich waters,they detached from the host to engage in foraging behavior.Inspired by the suckerfishes-shark system and the coordinated bond interaction,a large amount of Janus Au-Pt nanomotors with hydrogen peroxide(H_(2)O_(2))-driven capacity,analogous to suckerfishes,were attached onto immovable yolk-shell structured polydopamine-mesoporous silica(PDA-MS)micromotor as the host to create two-stage PDA-MS@Au-Pt micro@nanomotor.PDA-MS@Au-Pt micro@nanomotor moved directionally by self-thermophoresis under the propulsion of near infrared ray(NIR)light with low power density.When the PDA-MS@Au-Pt entered into the weak acidic environment formed by a low concentration of H_(2)O_(2),most small Au-Pt nanomotors were detached from the surface of PDA-MS due to the weak acidic sensitivity of the coordinated bond,and then performed self-diffusiophoresis in the environment containing a low concentration of H_(2)O_(2) as a chemical fuel.This bionic intelligent system,which consists of a large-sized micromotor and lots of small-sized nanomotors,should provide a new insight for active two-stage cargo delivery.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(grant No.XDB36000000)the National Basic Research Program of China(grant No.2020YFA0710702)the National Natural Science Foundation of China(grant Nos.51822207 and 51772292).
文摘Manufactured nanomaterials with unique properties have been extensively applied in various indus-trial,agricultural or medical fields.However,some of the properties have been identified to be closely related to nanomaterial toxicity.The"nano-paradox"has aroused concerns over the use and develop-ment of nanotechnology,which makes it difficult for regulatory agencies to regulate nanomaterials.The key to fulfilling proper nanomaterial regulation lies in the adequate understanding of the impact of nanomaterial properties on nano-bio interactions.To this end,we start the present work with a brief intro-duction to nano-bio interactions at different levels.Based on that,how key toxicity-associated properties of manufactured nanomaterials(i.e.,size,shape,chemical composition,surface properties,biocorona formation,agglomeration and/or aggregation state,and biodegradability)impact their toxicokinetics,cel-lular uptake,trafficking and responses,and toxicity mechanisms is deeply explored.Moreover,advanced analytical methods for studying nano-bio interactions are introduced.Furthermore,the current reg-ulatory and legislative frameworks for nanomaterial-containing products in different regions and/or countries are presented.Finally,we propose several challenges facing the nanotoxicology field and their possible solutions to shed light on the safety evaluation of nanomaterials.
基金This work was funded by the Fundamental Research Funds for the Central Universities(No.2232020A-02)National Natural Science Foundation of China(Nos.51774096,51871053,51902333)+3 种基金Shanghai Committee of Science and Technology(18JC1411200)Program for Innovative Research Team in University of Ministry of Education of China(IRT_16R13)Q.Zhang acknowledges financial support sponsored by Shanghai Saiiling Program(19YF1454000)Key Research Program of Frontier Sciences,CAS(Grant No.ZDBS-LY-JSC037).
文摘N-type Se&Lu-codoped Bi2Te3 nanopowders were prepared by hydrothermal method and sintered by spark plasma sintering technology to form dense samples.By further doping Se element into Lu-doped Bi2Te3 samples,the thickness of the nanosheets has the tendency to become thinner.The electrical conductivity of Lu0.1Bi1.9Te3−xSex material is reduced with the increasing Se content due to the reduced carrier concentration,while the Seeback coefficient values are enhanced.The lattice thermal conductivity of the Lu0.1Bi1.9Te3−xSex is greatly reduced due to the introduced point defects and atomic mass fluctuation.Finally,the Lu0.1Bi1.9Te2.7Se0.3 sample obtained a maximum ZT value of 0.85 at 420 K.This study provides a low-cost and simple low-temperature method to mass production of Se&Lu-codoped Bi2Te3 with high thermoelectric performance for practical applications.
基金supported by the National Key R&D Program of China(No.2016YFA0202701)the National Natural Science Foundation of China(Nos.51472055 and 61404034)+3 种基金External Cooperation Program of BIC,Chinese Academy of Sciences(No.121411KYS820150028)the 2015 Annual Beijing Talents Fund(No.2015000021223ZK32)the University of Chinese Academy of Sciences(No.Y8540XX2D2)the“thousands talents”program for the pioneer researcher and his innovation team,China.
文摘The ability to control surface wettability and liquid spreading on textured surfaces is of interest for extensive applications.Soft materials have prominent advantages for producing the smart coatings with multiple functions for strain sensing.Here,we report a simple method to prepare flexible hydrophobic smart coatings using graphene-polymer films.Arrays of individual patterns in the films were created by laser engraving and controlled the contact angle of small drops by pinning the contact lines in a horizontal tensile range of 0-200%.By means of experiments and model,we demonstrate that the ductility of drops is relied on the height-to-spacing ratio of the individual pattern and the intrinsic contact angle.Moreover,the change of drop size was utilized to measure the applied strain and liquid viscosity,enabling a strain sensitivity as high as 1068μm2/%.The proposed laser-etched stretchable graphene-polymer composite has potential applications in DNA microarrays,biological assays,soft robots,and so on.
基金supported by CAMS Research Units of Adaptive Evolution and Control of Emerging Viruses(2018RU009)Beijing New-star Plan of Science and Technology(Z181100006218080)+3 种基金supported by the Excellent Young Scientist Program of the National Natural Science Foundation of China(81822040)the National Youth Talent Support Programfunded by the National Natural Science Foundation of China(31900466)funded by the China Postdoctoral Science Foundation(2020T130080ZX).
文摘Rapidly spreading coronavirus disease 2019(COVID-19)is currently affecting the world.Specifically,cytokine storms are a key feature in a substantial num ber of COVID-19 patients,1 and studies from our group and others suggest that the IL-6/IL-6R cascade plays a dom inant role in symptom-correlated cytokine storms.
基金The study is supported by the National Natural Science Foundation of China(No.41001310)and the Natural Science Foundation of China-Guangdong Joint Fund(U1301253)The authors greatly appreciate Bureau of Land and Resource Yangshan for providing valuable land consolidation data.
文摘In order to select suitable sites for farmland consolidation projects,correlation analysis and evolutionary algorithms were used to optimize the evaluation of ecological,social and economic factors,avoiding subjective selection and ignorance of spatial relationships among land attributes.Multi-objective Genetic Algorithms(MOGA)were applied to select the best sites from the perspective of spatial relationship and land attribute evaluation.With carefully defined restrictions and variables,multi-objective optimization is able to select several suitable sites for farmland consolidation projects.The results from a case study in Yangshan,Guangdong of China showed that the selected sites were on the central and southern Yangshan with expected flat terrain and abundant water resources.An empirical experiment also demonstrated that the proposed method is able to provide well selected sites for land consolidation projects.
基金Supported by the State Hi-tech Research and Development Program (863 Program) of China (No. 2006AA040-101)
文摘The traditional design of the catalytic combustion gas sensor in Micro ElectroMechanical Systems (MEMS) micro-hotplate employs a Pt resistive track as the micro-heater. The realized structure and fabrication are the key elements of the micro-hotplate. Directly fabrication of micro-pellsitor catalyst is very difficult because of the small dimensions of the active area. In this paper, a novel micro-pellistor was designed by combining micro fabrication technique and nano technology. The supporting beams and micro-hotplate of the micro-pellistor were made of nonoporous alumina film. The active area of the designed and fabricated micro-pellistors ranges from 200×200 μm2 to 450×300 μm2. The micro- pellistor was heated by platinum thin film heater and the Pd catalyst was deposited by dipping the PdCl2 solution on the detecting element. The lowest power consumption is 50 mW at 500 °C and the maximum temperature can reach 900 °C before rupture. The response of the devices to methane is also tested. The new design provides a new way to fabricate micro-pellistor.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB13020600)the National Natural Science Foundation of China(31671325)
文摘RNA editing was first discovered in mitochondrial RNA molecular. However, whether adenosine-toinosine(A-to-I) RNA editing has functions in nuclear genes involved in mitochondria remains elusive.Here, we retrieved 707,246 A-to-I RNA editing sites in Macaca mulatta leveraging massive transcriptomes of 30 different tissues and genomes of nine tissues, together with the reported data, and found that A-to-I RNA editing occurred frequently in nuclear genes that have functions in mitochondria. The mitochondrial structure, the level of ATP production, and the expression of some key genes involved in mitochondrial function were dysregulated after knocking down the expression of ADAR1 and ADAR2, the key genes encoding the enzyme responsible for RNA editing. When investigating dynamic changes of RNA editing during brain development, an amino-acid-changing RNA editing site(I234/V) in MFN1, a mediator of mitochondrial fusion, was identified to be significantly correlated with age, and could influence the function of MFN1. When studying transcriptomes of brain disorder, we found that dysregulated RNA editing sites in autism were also enriched within genes having mitochondrial functions. These data indicated that RNA editing had a significant function in mitochondria via their influence on nuclear genes.
基金Project supported by the National Natural Science Foundation of China （No. 10675158）.
文摘The interaction of colloidal gold with Taq DNA polymerase （Taq） was investigated in this study. Taq-gold conjugate was formed by adding the enzyme to the colloidal gold solution, as evidenced by UV-Vis spectroscopy, X-ray photoelectron spectroscopy, and photon cross correlation spectroscopy measurements. The conjugate was further characterized by transmission electron microscopy. It was found that the Taq-gold conjugate particles were still spherical and well-dispersed. The influence of gold nanoparticles on the bioactivity of Taq was studied by analyzing the yield of the polymerase chain reaction amplification. Results indicated that the enzymatic activity of Taq decreased after interaction with the colloidal gold.
