We report a study of the electronic structure of BaFe_(2)As_(2) under uniaxial strains using angle-resolved photoemission spectroscopy and transport measurements. Two electron bands at the MY point, with an energy spl...We report a study of the electronic structure of BaFe_(2)As_(2) under uniaxial strains using angle-resolved photoemission spectroscopy and transport measurements. Two electron bands at the MY point, with an energy splitting of 50 meV in the strain-free sample, shift downward and merge into each other under a large uniaxial strain, while three hole bands at theГ point shift downward together. However, we also observed an enhancement of the resistance anisotropy under uniaxial strains by electrical transport measurements, implying that the applied strains strengthen the electronic nematic order in BaFe_(2)As_(2). These observations suggest that the splitting of these two electron bands at the MY point is not caused by the nematic order in BaFe_(2)As_(2).展开更多
Plant architecture is a collection of major agronomic traits that determines rice grain production,and it is mainly influenced by tillering,tiller angle,plant height and panicle morphology(Wang and Li 2006).Tiller ang...Plant architecture is a collection of major agronomic traits that determines rice grain production,and it is mainly influenced by tillering,tiller angle,plant height and panicle morphology(Wang and Li 2006).Tiller angle is one of the critical components that determines rice plant architecture,which in turn influences grain yield mainly due to its large impact on plant density(Wang et al.2022).展开更多
Subway tunnels often suffer from surface pathologies such as cracks,corrosion,fractures,peeling,water and sand infiltration,and sudden hazards caused by foreign object intrusions.Installing a mobile visual pathology s...Subway tunnels often suffer from surface pathologies such as cracks,corrosion,fractures,peeling,water and sand infiltration,and sudden hazards caused by foreign object intrusions.Installing a mobile visual pathology sensing system at the front end of operating trains is a critical measure to ensure subway safety.Taking leakage as the typical pathology,a tunnel pathology automatic visual detection method based on Deeplabv3+(ASTPDS)was proposed to achieve automatic and high-precision detection and pixel-level morphology extraction of pathologies.Compared with similar methods,this approach showed significant advantages and achieved a detection accuracy of 93.12%,surpassing FCN and U-Net.Moreover,it also exceeded the recall rates for detecting leaks of FCN and U-Net by 8.33%and 8.19%,respectively.展开更多
Background: The effect of amylases combined with exogenous carbohydrase and protease in a newly harvested corn diet on starch digestibility, intestine health and cecal microbiota was investigated in broiler chickens.M...Background: The effect of amylases combined with exogenous carbohydrase and protease in a newly harvested corn diet on starch digestibility, intestine health and cecal microbiota was investigated in broiler chickens.Methods: Two hunderd and eighty-eight 5-day-old female chickens were randomly divided into six treatments: a newly harvested corn-soybean meal diet(control); control supplemented with 1,500 U/g α-amylase(Enzyme A);Enzyme A + 300 U/g amylopectase + 20,000 U/g glucoamylase(Enzyme B); Enzyme B + protease 10,000 U/g(Enzyme C); Enzyme C + xylanase 15,000 U/g(Enzyme D); and Enzyme D + cellulase 200 U/g + pectinase 1,000 U/g(Enzyme E). Growth performance, starch digestibility, digestive organ morphology, and intestinal microbiota were evaluated in the birds at 16 and 23 d of age.Results: Compared with the control diet, supplementation with Enzyme A significantly decreased ileum lesion scoring at 16 d of age(P < 0.05); supplementation with Enzyme B or Enzyme C showed positive effects on ileal amylopectin and total starch digestibility(P < 0.05); Broilers fed with a diet supplemented with Enzyme D had a tendency to decrease body weight gain at 23 d. Enzyme E supplementation improved lesion scoring of jejunum and ileum at 16 d(P < 0.05), and increased ileal amylopectin or total starch digestibility at 23 d(P < 0.05).Supplementation of enzymes changed cecal microbiota diversity. High numbers of Campylobacter, Helicobacter and Butyricicoccus, Anaerostipes and Bifidobacterium, Sutterella and Odoribacter were the main genera detected in supplementations with Enzymes B, C, D, and E respectively.Conclusions: Supplementation with amylase combined with glucoamylase or protease showed a beneficial effect on starch digestibility and intestinal microbiota diversity, and increased growth of broilers fed with newly harvested corn.展开更多
Spinal cord injury is a challenge in orthopedics because it causes irreversible damage to the central nervous system.Therefore,early treatment to prevent lesion expansion is crucial for the management of patients with...Spinal cord injury is a challenge in orthopedics because it causes irreversible damage to the central nervous system.Therefore,early treatment to prevent lesion expansion is crucial for the management of patients with spinal cord injury.Bexarotene,a type of retinoid,exerts therapeutic effects on patients with cutaneous T-cell lymphoma and Parkinson's disease.Bexarotene has been proven to promote autophagy,but it has not been used in the treatment of spinal cord injury.To investigate the effects of bexarotene on spinal cord injury,we established a mouse model of T11–T12 spinal cord contusion and performed daily intraperitoneal injection of bexarotene for 5 consecutive days.We found that bexarotene effectively reduced the deposition of collagen and the number of pathological neurons in the injured spinal cord,increased the number of synapses of nerve cells,reduced oxidative stress,inhibited pyroptosis,promoted the recovery of motor function,and reduced death.Inhibition of autophagy with 3-methyladenine reversed the effects of bexarotene on spinal cord injury.Bexarotene enhanced the nuclear translocation of transcription factor E3,which further activated AMP-activated protein kinase-S-phase kinase-associated protein 2-coactivator-associated arginine methyltransferase 1 and AMP-activated protein kinase-mammalian target of rapamycin signaling pathways.Intravenous injection of transcription factor E3 sh RNA or intraperitoneal injection of compound C,an AMP-activated protein kinase blocker,inhibited the effects of bexarotene.These findings suggest that bexarotene regulates nuclear translocation of transcription factor E3 through the AMP-activated protein kinase-Sphase kinase-associated protein 2-coactivator-associated arginine methyltransferase 1 and AMP-activated protein kinase-mammalian target of rapamycin signal pathways,promotes autophagy,decreases reactive oxygen species level,inhibits pyroptosis,and improves motor function after spinal cord injury.展开更多
Uniaxial pressure or strain can introduce a symmetry-breaking distortion on the lattice and may alter the ground states of a material. Compared to hydrostatic pressure, a unique feature of the uniaxial-pressure measur...Uniaxial pressure or strain can introduce a symmetry-breaking distortion on the lattice and may alter the ground states of a material. Compared to hydrostatic pressure, a unique feature of the uniaxial-pressure measurements is that a tensile force can be applied and thus a “negative” pressure can be achieved. In doing so, both ends of the sample are usually glued on the frame of the uniaxial-pressure device. The maximum force that can be applied onto the sample is sometimes limited by the shear strength of the glue, the quality of the interface between the sample and the glue, etc. Here we use focused ion beam to reduce the width of the middle part of the sample, which can significantly increase the effective pressure applied on the sample. By applying this technique to a home-made piezobender-based uniaxial-pressure device, we can easily increase the effective pressure by one or two orders of magnitude as shown by the change of the superconducting transition temperature of an iron-based superconductor. Our method thus provides a possible way to increase the upper limit of the pressure for the uniaxial-pressure devices.展开更多
We investigate the uniaxial-pressure dependence of resistivity for URu_(2−x)Fe_(x)Si_(2)samples with x=0 and 0.2,which host a hidden order(HO)and a large-moment antiferromagnetic(LMAFM)phase,respectively.For both samp...We investigate the uniaxial-pressure dependence of resistivity for URu_(2−x)Fe_(x)Si_(2)samples with x=0 and 0.2,which host a hidden order(HO)and a large-moment antiferromagnetic(LMAFM)phase,respectively.For both samples,the elastoresistivityζshows a seemingly divergent behavior above the transition temperature T_(0)and a quick decrease below it.We find that the temperature dependence ofζfor both samples can be well described by assuming the uniaxial pressure effect on the gap or certain energy scale except forζ(110)of the x=0 sample,which exhibits a nonzero residual value at 0 K.We show that this provides a qualitative difference between the HO and LMAFM phases.Our results suggest that there is an in-plane anisotropic response to the uniaxial pressure that only exists in the hidden order state without necessarily breaking the rotational lattice symmetry.展开更多
Permafrost is widely distributed in China and around the world.In permafrost regions,soil frost heave and thawing are severe and frequent,and can destabilize pile foundations.To this end,a finite element model of a si...Permafrost is widely distributed in China and around the world.In permafrost regions,soil frost heave and thawing are severe and frequent,and can destabilize pile foundations.To this end,a finite element model of a single pile in frozen soil is established to investigate the frost heave and frost jacking response to ensure its safety in the Qinghai-Tibet Plateau.Firstly,a hydro-thermal coupling model of a single pile in frozen soil is established based on coupling parameters and initial and boundary conditions.Then the temperature and moisture distributions are analyzed through the established coupling model.A hydro-thermo-mechanical coupling model is developed by importing the ice content and temperature results.Simulation results indicate that the amount of frost heave is greater at locations closer to the ground surface,and the displacement is smaller for frozen soil that is closer to the side of the pile.The results on frost jacking behavior of piles from this study can serve as a reference for the design,construction and maintenance of foundations.展开更多
The human-computer interaction (HCI) is now playing a great role in computer technology. This study introduces an automatic document control technique which is based on the human hand waving movements. The recognition...The human-computer interaction (HCI) is now playing a great role in computer technology. This study introduces an automatic document control technique which is based on the human hand waving movements. The recognition of hand movement is realized according to the surface electromyography (sEMG). A collector is set on the forearm. The sEMG signal is recorded and conveyed to a PC terminal by using wireless Zigbee. An automatic algorithm is developed in order to extract the characteristics of sEMG, recognize the waving movements, and transmit to document control command. The developed human-computer interaction technique can be used as a new gallery for teaching, as well as an assistant tool for disabled person.展开更多
1.Background Materials science is the study of materials,their properties and their applications.As the rapid development of material science,materials tend to approach multifunctionality.Multifunctional m...1.Background Materials science is the study of materials,their properties and their applications.As the rapid development of material science,materials tend to approach multifunctionality.Multifunctional materials are designed to perform multiple responsibilities through prudent combinations of different functional capabilities.展开更多
Knowledge on corrosion behaviors and kinetics of nanoscale zero-valent iron(nZVI)in aquatic environment is particularly significant for understanding the reactivity,longevity and stability of nZVI,as well as providing...Knowledge on corrosion behaviors and kinetics of nanoscale zero-valent iron(nZVI)in aquatic environment is particularly significant for understanding the reactivity,longevity and stability of nZVI,as well as providing theoretical guidance for developing a cost-effective nZVI-based technology and designing large-scale applications.Herein,this review gives a holistic overview on the corrosion behaviors and kinetics of nZVI in water.Firstly,Eh-pH diagram is introduced to predict the thermodynamics trend of iron corrosion.The morphological,structural,and compositional evolution of(modified-)nZVI under different environmental conditions,assisted with microscopic and spectroscopic evidence,is then summarized.Afterwards,common analytical methods and characterization technologies are categorized to establish time-resolved corrosion kinetics of nZVI in water.Specifically,stable models for calculating the corrosion rate constant of nZVI as well as electrochemical methods for monitoring the redox reaction are discussed,emphasizing their capabilities in studying the dynamic iron corrosion processes.Finally,in the future,more efforts are encouraged to study the corrosion behaviors of nZVI in long-term practical application and further build nanoparticles with precisely tailored properties.We expect that our work can deepen the understanding of the nZVI chemistry in aquatic environment.展开更多
Hosts evolve defensive strategies to minimize the reproductive costs of brood parasitism,in turn,the hosts'defense promote the optimization of cuckoo parasitism strategies(Soler 2017).Recognizing foreign eggs and ...Hosts evolve defensive strategies to minimize the reproductive costs of brood parasitism,in turn,the hosts'defense promote the optimization of cuckoo parasitism strategies(Soler 2017).Recognizing foreign eggs and selectively removing them from the nest can minimize the fitness costs associated with rearing parasitic fledglings(Soler 2017).Since Rothstein(1971)first experimented with the addition of a model egg to a host nest in the early incubation period to study host egg recognition,the use of model eggs has become one of the most important methods for testing the egg recognition abilities of hosts(Hauber et al.2019).Some studies have looked at various egg colors and their effect on host egg rejection and found differential responses to egg colors(for more details,see Supplementary Materials),highlighting that more work needs to examine the effect of model egg color on host egg rejection behavior.展开更多
Tiller angle is a key agricultural trait that establishes plant architecture,which in turn strongly affects grain yield by influencing planting density in rice.The shoot gravity response plays a crucial role in the re...Tiller angle is a key agricultural trait that establishes plant architecture,which in turn strongly affects grain yield by influencing planting density in rice.The shoot gravity response plays a crucial role in the regulation of tiller angle in rice,but the underlying molecular mechanism is largely unknown.Here,we report the identification of the BIG TILLER ANGLE2(BTA2),which regulates tiller angle by controlling the shoot gravity response in rice.Loss-of-function mutation of BTA2 dramatically reduced auxin content and affected auxin distribution in rice shoot base,leading to impaired gravitropism and therefore a big tiller angle.BTA2 interacted with AUXIN RESPONSE FACTOR7(ARF7)to modulate rice tiller angle through the gravity signaling pathway.The BTA2 protein was highly conserved during evolution.Sequence variation in the BTA2 promoter of indica cultivars harboring a less expressed BTA2 allele caused lower BTA2 expression in shoot base and thus wide tiller angle during rice domestication.Overexpression of BTA2 significantly increased grain yield in the elite rice cultivar Huanghuazhan under appropriate dense planting conditions.Our findings thus uncovered the BTA2-ARF7 module that regulates tiller angle by mediating the shoot gravity response.Our work offers a target for genetic manipulation of plant architecture and valuable information for crop improvement by producing the ideal plant type.展开更多
COVID-19 patients can recover with a median SARS-CoV-2 clearance of 20 days post initial symptoms(PIS).However,we observed some COVID-19 patients with existing SARS-CoV-2 for more than 50 days PIS.This study aimed to ...COVID-19 patients can recover with a median SARS-CoV-2 clearance of 20 days post initial symptoms(PIS).However,we observed some COVID-19 patients with existing SARS-CoV-2 for more than 50 days PIS.This study aimed to investigate the cause of viral clearance delay and the infectivity in these patients.Demographic data and clinical characteristics of 22 long-term COVID-19 patients were collected.The median age of the studied cohort was59.83±12.94 years.All patients were clinically cured after long-term SARS-CoV-2 infection ranging from 53 to112 days PIS.Peripheral lymphocytes counts were normal.The ratios of interferon gamma(IFN-c)-secreting cells to total CD4^(+)and CD8^(+)cells were normal as 24.68%±9.60%and 66.41%±14.87%respectively.However,the number of IFNc-secreting NK cells diminished(58.03%±11.78%).All patients presented detectable IgG,which positively correlated with mild neutralizing activity(Mean value neutralisation antibodies titers=157.2,P=0.05).No SARS-CoV-2 virus was isolated in Vero E6 cells inoculated with nasopharyngeal swab samples from all patients 50 days PIS,and the cytopathic effect was lacking.But one sample was positive for SARS-CoV-2 nucleic acid test in cell supernatants after two passages.Genome sequencing revealed that only three synonymous variants were identified in spike protein coding regions.In conclusion,decreased IFN-c production by NK cells and low neutralizing antibodies might favor SARS-CoV-2 long-term existence.Further,low viral load and weak viral pathogenicity were observed in COVID-19 patients with long-term SARSCoV-2 infection.展开更多
A high-dimensional quantum key distribution(QKD), which adopts degrees of freedom of the orbital angular momentum(OAM) states, is beneficial to realize secure and high-speed QKD. However, the helical phase of a vortex...A high-dimensional quantum key distribution(QKD), which adopts degrees of freedom of the orbital angular momentum(OAM) states, is beneficial to realize secure and high-speed QKD. However, the helical phase of a vortex beam that carries OAM is sensitive to the atmospheric turbulence and easily distorted. In this paper, an adaptive compensation method using deep learning technology is developed to improve the performance of OAM-encoded QKD schemes. A convolutional neural network model is first trained to learn the mapping relationship of intensity profiles of inputs and the turbulent phase, and such mapping is used as feedback to control a spatial light modulator to generate a phase screen to correct the distorted vortex beam. Then an OAM-encoded QKD scheme with the capability of real-time phase correction is designed, in which the compensation module only needs to extract the intensity distributions of the Gaussian probe beam and thus ensures that the information encoded on OAM states would not be eavesdropped. The results show that our method can efficiently improve the mode purity of the encoded OAM states and extend the secure distance for the involved QKD protocols in the free-space channel, which is not limited to any specific QKD protocol.展开更多
Al_(2)O_(3)-Y_(2)O_(3) composite powder with TiO_(2) additive was plasma sprayed to prepare Al_(2)O_(3)-Y_(2)O_(3) composite coatings.The micro structure and properties evolution of the Al_(2)O_(3)-Y_(2)O_(3) coatings...Al_(2)O_(3)-Y_(2)O_(3) composite powder with TiO_(2) additive was plasma sprayed to prepare Al_(2)O_(3)-Y_(2)O_(3) composite coatings.The micro structure and properties evolution of the Al_(2)O_(3)-Y_(2)O_(3) coatings during high temperature and thermal shock resistance were investigated.The results show that the micro structure of the Al_(2)O_(3)-Y_(2)O_(3)-TiO_(2) coating is more uniform than that of the Al_(2)O_(3)-Y_(2)O_(3) coating.Meanwhile,amorphous phase is formed in the two coatings.The Al_(2)O_(3)-Y_(2)O_(3)(-TiO_(2)) coatings were heat treated for 2 h at temperatures of 800,1000 and 1200℃,respectively.It is found that the microstructure and properties of the two coatings have no obvious change at 800℃.Some of the amorphous phase is crystallized at1000℃,and meanwhile Y_(2)O_(3) and Al_(2)O_(3) react to form YAG phase and YAM phase.At 1200℃,all of the amorphous phases are crystallized.After heat treatment,the micro hardness of the two coatings is increased.The thermal shock resistance of the Al_(2)O_(3)-Y_(2)O_(3) system coatings can be improved by using TC4 titanium alloy as substrate and with NiCrAlY bonding layer.Moreover,the Al_(2)O_(3)-Y_(2)O_(3)-TiO_(2) coating exhibits better thermal shock resistance due to the addition of TiO_(2).展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11888101 and U1832202)the Chinese Academy of Sciences (Grant Nos.QYZDB-SSWSLH043,XDB28000000,and XDB33000000)+1 种基金the K.C.Wong Education Foundation (Grant No.GJTD-2018-01)the Informatization Plan of Chinese Academy of Sciences (Grant No.CAS-WX2021SF-0102)。
文摘We report a study of the electronic structure of BaFe_(2)As_(2) under uniaxial strains using angle-resolved photoemission spectroscopy and transport measurements. Two electron bands at the MY point, with an energy splitting of 50 meV in the strain-free sample, shift downward and merge into each other under a large uniaxial strain, while three hole bands at theГ point shift downward together. However, we also observed an enhancement of the resistance anisotropy under uniaxial strains by electrical transport measurements, implying that the applied strains strengthen the electronic nematic order in BaFe_(2)As_(2). These observations suggest that the splitting of these two electron bands at the MY point is not caused by the nematic order in BaFe_(2)As_(2).
基金grants from the Natural Science Foundation of Zhejiang Province,China(LTGN23C130001)the Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City,China(2021JJLH0045)+1 种基金the State Key Laboratory of Rice Biology and Breeding-Independent Project,China(2023ZZKT20304)the China Agriculture Research System(CARS-01-14)。
文摘Plant architecture is a collection of major agronomic traits that determines rice grain production,and it is mainly influenced by tillering,tiller angle,plant height and panicle morphology(Wang and Li 2006).Tiller angle is one of the critical components that determines rice plant architecture,which in turn influences grain yield mainly due to its large impact on plant density(Wang et al.2022).
文摘Subway tunnels often suffer from surface pathologies such as cracks,corrosion,fractures,peeling,water and sand infiltration,and sudden hazards caused by foreign object intrusions.Installing a mobile visual pathology sensing system at the front end of operating trains is a critical measure to ensure subway safety.Taking leakage as the typical pathology,a tunnel pathology automatic visual detection method based on Deeplabv3+(ASTPDS)was proposed to achieve automatic and high-precision detection and pixel-level morphology extraction of pathologies.Compared with similar methods,this approach showed significant advantages and achieved a detection accuracy of 93.12%,surpassing FCN and U-Net.Moreover,it also exceeded the recall rates for detecting leaks of FCN and U-Net by 8.33%and 8.19%,respectively.
基金supported by the System for Poultry Production Technology,Beijing Innovation Research Team of Modern Agriculture(BAIC04–2016)
文摘Background: The effect of amylases combined with exogenous carbohydrase and protease in a newly harvested corn diet on starch digestibility, intestine health and cecal microbiota was investigated in broiler chickens.Methods: Two hunderd and eighty-eight 5-day-old female chickens were randomly divided into six treatments: a newly harvested corn-soybean meal diet(control); control supplemented with 1,500 U/g α-amylase(Enzyme A);Enzyme A + 300 U/g amylopectase + 20,000 U/g glucoamylase(Enzyme B); Enzyme B + protease 10,000 U/g(Enzyme C); Enzyme C + xylanase 15,000 U/g(Enzyme D); and Enzyme D + cellulase 200 U/g + pectinase 1,000 U/g(Enzyme E). Growth performance, starch digestibility, digestive organ morphology, and intestinal microbiota were evaluated in the birds at 16 and 23 d of age.Results: Compared with the control diet, supplementation with Enzyme A significantly decreased ileum lesion scoring at 16 d of age(P < 0.05); supplementation with Enzyme B or Enzyme C showed positive effects on ileal amylopectin and total starch digestibility(P < 0.05); Broilers fed with a diet supplemented with Enzyme D had a tendency to decrease body weight gain at 23 d. Enzyme E supplementation improved lesion scoring of jejunum and ileum at 16 d(P < 0.05), and increased ileal amylopectin or total starch digestibility at 23 d(P < 0.05).Supplementation of enzymes changed cecal microbiota diversity. High numbers of Campylobacter, Helicobacter and Butyricicoccus, Anaerostipes and Bifidobacterium, Sutterella and Odoribacter were the main genera detected in supplementations with Enzymes B, C, D, and E respectively.Conclusions: Supplementation with amylase combined with glucoamylase or protease showed a beneficial effect on starch digestibility and intestinal microbiota diversity, and increased growth of broilers fed with newly harvested corn.
基金grants from Zhejiang Provincial Medicine and Health Technology Project,No.2021KY214(to SS)Zhejiang Provincial Science and Technology Project of Traditional Chinese Medicine,No.2021ZB183(to HX)。
文摘Spinal cord injury is a challenge in orthopedics because it causes irreversible damage to the central nervous system.Therefore,early treatment to prevent lesion expansion is crucial for the management of patients with spinal cord injury.Bexarotene,a type of retinoid,exerts therapeutic effects on patients with cutaneous T-cell lymphoma and Parkinson's disease.Bexarotene has been proven to promote autophagy,but it has not been used in the treatment of spinal cord injury.To investigate the effects of bexarotene on spinal cord injury,we established a mouse model of T11–T12 spinal cord contusion and performed daily intraperitoneal injection of bexarotene for 5 consecutive days.We found that bexarotene effectively reduced the deposition of collagen and the number of pathological neurons in the injured spinal cord,increased the number of synapses of nerve cells,reduced oxidative stress,inhibited pyroptosis,promoted the recovery of motor function,and reduced death.Inhibition of autophagy with 3-methyladenine reversed the effects of bexarotene on spinal cord injury.Bexarotene enhanced the nuclear translocation of transcription factor E3,which further activated AMP-activated protein kinase-S-phase kinase-associated protein 2-coactivator-associated arginine methyltransferase 1 and AMP-activated protein kinase-mammalian target of rapamycin signaling pathways.Intravenous injection of transcription factor E3 sh RNA or intraperitoneal injection of compound C,an AMP-activated protein kinase blocker,inhibited the effects of bexarotene.These findings suggest that bexarotene regulates nuclear translocation of transcription factor E3 through the AMP-activated protein kinase-Sphase kinase-associated protein 2-coactivator-associated arginine methyltransferase 1 and AMP-activated protein kinase-mammalian target of rapamycin signal pathways,promotes autophagy,decreases reactive oxygen species level,inhibits pyroptosis,and improves motor function after spinal cord injury.
基金Project supported by the National Key Research and Development Program of China (Grant Nos. 2022YFA1403402,2021YFA1400401, 2020YFA0406003, and 2017YFA0302903)the National Natural Science Foundation of China (Grant Nos. 11961160699 and 11874401)the Chinese Academy of Sciences (Grant Nos. XDB33000000 and GJTD-2020-01)。
文摘Uniaxial pressure or strain can introduce a symmetry-breaking distortion on the lattice and may alter the ground states of a material. Compared to hydrostatic pressure, a unique feature of the uniaxial-pressure measurements is that a tensile force can be applied and thus a “negative” pressure can be achieved. In doing so, both ends of the sample are usually glued on the frame of the uniaxial-pressure device. The maximum force that can be applied onto the sample is sometimes limited by the shear strength of the glue, the quality of the interface between the sample and the glue, etc. Here we use focused ion beam to reduce the width of the middle part of the sample, which can significantly increase the effective pressure applied on the sample. By applying this technique to a home-made piezobender-based uniaxial-pressure device, we can easily increase the effective pressure by one or two orders of magnitude as shown by the change of the superconducting transition temperature of an iron-based superconductor. Our method thus provides a possible way to increase the upper limit of the pressure for the uniaxial-pressure devices.
基金supported by the National Key Research and Development Program of China(Grant Nos.2020YFA0406003,2021YFA1400401,2017YFA0302903,and 2017YFA0303100)the National Natural Science Foundation of China(Grant Nos.11961160699,11874401,and 11974397)+1 种基金the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant Nos.XDB33000000 and XDB25000000)the K.C.Wong Education Foundation(Grant No.GJTD2020-01).
文摘We investigate the uniaxial-pressure dependence of resistivity for URu_(2−x)Fe_(x)Si_(2)samples with x=0 and 0.2,which host a hidden order(HO)and a large-moment antiferromagnetic(LMAFM)phase,respectively.For both samples,the elastoresistivityζshows a seemingly divergent behavior above the transition temperature T_(0)and a quick decrease below it.We find that the temperature dependence ofζfor both samples can be well described by assuming the uniaxial pressure effect on the gap or certain energy scale except forζ(110)of the x=0 sample,which exhibits a nonzero residual value at 0 K.We show that this provides a qualitative difference between the HO and LMAFM phases.Our results suggest that there is an in-plane anisotropic response to the uniaxial pressure that only exists in the hidden order state without necessarily breaking the rotational lattice symmetry.
基金supported by the National Natural Science Foundation of China(Nos.42071078,41731281 and 41701068)the Natural Science Foundation of Qinghai Province,China(No.2021-ZJ-908).
文摘Permafrost is widely distributed in China and around the world.In permafrost regions,soil frost heave and thawing are severe and frequent,and can destabilize pile foundations.To this end,a finite element model of a single pile in frozen soil is established to investigate the frost heave and frost jacking response to ensure its safety in the Qinghai-Tibet Plateau.Firstly,a hydro-thermal coupling model of a single pile in frozen soil is established based on coupling parameters and initial and boundary conditions.Then the temperature and moisture distributions are analyzed through the established coupling model.A hydro-thermo-mechanical coupling model is developed by importing the ice content and temperature results.Simulation results indicate that the amount of frost heave is greater at locations closer to the ground surface,and the displacement is smaller for frozen soil that is closer to the side of the pile.The results on frost jacking behavior of piles from this study can serve as a reference for the design,construction and maintenance of foundations.
文摘The human-computer interaction (HCI) is now playing a great role in computer technology. This study introduces an automatic document control technique which is based on the human hand waving movements. The recognition of hand movement is realized according to the surface electromyography (sEMG). A collector is set on the forearm. The sEMG signal is recorded and conveyed to a PC terminal by using wireless Zigbee. An automatic algorithm is developed in order to extract the characteristics of sEMG, recognize the waving movements, and transmit to document control command. The developed human-computer interaction technique can be used as a new gallery for teaching, as well as an assistant tool for disabled person.
文摘1.Background Materials science is the study of materials,their properties and their applications.As the rapid development of material science,materials tend to approach multifunctionality.Multifunctional materials are designed to perform multiple responsibilities through prudent combinations of different functional capabilities.
基金supported by the National Natural Science Foundation of China (No.52200184)the Fundamental Research Funds for Central Universities (No.12060096014)。
文摘Knowledge on corrosion behaviors and kinetics of nanoscale zero-valent iron(nZVI)in aquatic environment is particularly significant for understanding the reactivity,longevity and stability of nZVI,as well as providing theoretical guidance for developing a cost-effective nZVI-based technology and designing large-scale applications.Herein,this review gives a holistic overview on the corrosion behaviors and kinetics of nZVI in water.Firstly,Eh-pH diagram is introduced to predict the thermodynamics trend of iron corrosion.The morphological,structural,and compositional evolution of(modified-)nZVI under different environmental conditions,assisted with microscopic and spectroscopic evidence,is then summarized.Afterwards,common analytical methods and characterization technologies are categorized to establish time-resolved corrosion kinetics of nZVI in water.Specifically,stable models for calculating the corrosion rate constant of nZVI as well as electrochemical methods for monitoring the redox reaction are discussed,emphasizing their capabilities in studying the dynamic iron corrosion processes.Finally,in the future,more efforts are encouraged to study the corrosion behaviors of nZVI in long-term practical application and further build nanoparticles with precisely tailored properties.We expect that our work can deepen the understanding of the nZVI chemistry in aquatic environment.
基金supported by Key R&D projects in Ningxia(talent introduction project,2021BEB04015)Fundamental Research Funds for Central Universities,North Minzu University(2021KYQD05)supported by the National Natural Science Foundation of China(Nos.31970427,32270526)and the specific research fund of The Innovation Platform for Academicians of Hainan Province.
文摘Hosts evolve defensive strategies to minimize the reproductive costs of brood parasitism,in turn,the hosts'defense promote the optimization of cuckoo parasitism strategies(Soler 2017).Recognizing foreign eggs and selectively removing them from the nest can minimize the fitness costs associated with rearing parasitic fledglings(Soler 2017).Since Rothstein(1971)first experimented with the addition of a model egg to a host nest in the early incubation period to study host egg recognition,the use of model eggs has become one of the most important methods for testing the egg recognition abilities of hosts(Hauber et al.2019).Some studies have looked at various egg colors and their effect on host egg rejection and found differential responses to egg colors(for more details,see Supplementary Materials),highlighting that more work needs to examine the effect of model egg color on host egg rejection behavior.
基金supported by the Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City(2021JJLH0045)the Natural Science Foundation of Zhejiang Province(LTGN23C130001)+2 种基金National Key R&D Program of China(2020YFE0202300)the Key Research and Development Program of Zhejiang Province(2021C02056)the Agricultural Science and Technology Innovation Program(CAAS‐ASTIP‐2013‐CNRRI).
文摘Tiller angle is a key agricultural trait that establishes plant architecture,which in turn strongly affects grain yield by influencing planting density in rice.The shoot gravity response plays a crucial role in the regulation of tiller angle in rice,but the underlying molecular mechanism is largely unknown.Here,we report the identification of the BIG TILLER ANGLE2(BTA2),which regulates tiller angle by controlling the shoot gravity response in rice.Loss-of-function mutation of BTA2 dramatically reduced auxin content and affected auxin distribution in rice shoot base,leading to impaired gravitropism and therefore a big tiller angle.BTA2 interacted with AUXIN RESPONSE FACTOR7(ARF7)to modulate rice tiller angle through the gravity signaling pathway.The BTA2 protein was highly conserved during evolution.Sequence variation in the BTA2 promoter of indica cultivars harboring a less expressed BTA2 allele caused lower BTA2 expression in shoot base and thus wide tiller angle during rice domestication.Overexpression of BTA2 significantly increased grain yield in the elite rice cultivar Huanghuazhan under appropriate dense planting conditions.Our findings thus uncovered the BTA2-ARF7 module that regulates tiller angle by mediating the shoot gravity response.Our work offers a target for genetic manipulation of plant architecture and valuable information for crop improvement by producing the ideal plant type.
基金support by National Natural Science Foundation of China under Grant(81800095)Key Scientific and Technological Project of Hubei province(2020FCA004)。
文摘COVID-19 patients can recover with a median SARS-CoV-2 clearance of 20 days post initial symptoms(PIS).However,we observed some COVID-19 patients with existing SARS-CoV-2 for more than 50 days PIS.This study aimed to investigate the cause of viral clearance delay and the infectivity in these patients.Demographic data and clinical characteristics of 22 long-term COVID-19 patients were collected.The median age of the studied cohort was59.83±12.94 years.All patients were clinically cured after long-term SARS-CoV-2 infection ranging from 53 to112 days PIS.Peripheral lymphocytes counts were normal.The ratios of interferon gamma(IFN-c)-secreting cells to total CD4^(+)and CD8^(+)cells were normal as 24.68%±9.60%and 66.41%±14.87%respectively.However,the number of IFNc-secreting NK cells diminished(58.03%±11.78%).All patients presented detectable IgG,which positively correlated with mild neutralizing activity(Mean value neutralisation antibodies titers=157.2,P=0.05).No SARS-CoV-2 virus was isolated in Vero E6 cells inoculated with nasopharyngeal swab samples from all patients 50 days PIS,and the cytopathic effect was lacking.But one sample was positive for SARS-CoV-2 nucleic acid test in cell supernatants after two passages.Genome sequencing revealed that only three synonymous variants were identified in spike protein coding regions.In conclusion,decreased IFN-c production by NK cells and low neutralizing antibodies might favor SARS-CoV-2 long-term existence.Further,low viral load and weak viral pathogenicity were observed in COVID-19 patients with long-term SARSCoV-2 infection.
基金National Natural Science Foundation of China(11704412)Key Research and Development Program of Shaanxi(2019ZDLGY09-01)+1 种基金Innovative Talents Promotion Plan in Shaanxi Province(2020KJXX-011)National University of Defense Technology(19-QNCXJ-009)。
文摘A high-dimensional quantum key distribution(QKD), which adopts degrees of freedom of the orbital angular momentum(OAM) states, is beneficial to realize secure and high-speed QKD. However, the helical phase of a vortex beam that carries OAM is sensitive to the atmospheric turbulence and easily distorted. In this paper, an adaptive compensation method using deep learning technology is developed to improve the performance of OAM-encoded QKD schemes. A convolutional neural network model is first trained to learn the mapping relationship of intensity profiles of inputs and the turbulent phase, and such mapping is used as feedback to control a spatial light modulator to generate a phase screen to correct the distorted vortex beam. Then an OAM-encoded QKD scheme with the capability of real-time phase correction is designed, in which the compensation module only needs to extract the intensity distributions of the Gaussian probe beam and thus ensures that the information encoded on OAM states would not be eavesdropped. The results show that our method can efficiently improve the mode purity of the encoded OAM states and extend the secure distance for the involved QKD protocols in the free-space channel, which is not limited to any specific QKD protocol.
基金Project supported by the National Natural Science Foundation of China(51672067,51541208,51102074)the Natural Science Foundation of Hebei Province(E2018202034,E2015202070)+1 种基金the Foundation for Talent Training Project in Hebei Province(A2016002026)the Foundation for the Top Talents in Universities of Hebei Province(SLRC2017027)。
文摘Al_(2)O_(3)-Y_(2)O_(3) composite powder with TiO_(2) additive was plasma sprayed to prepare Al_(2)O_(3)-Y_(2)O_(3) composite coatings.The micro structure and properties evolution of the Al_(2)O_(3)-Y_(2)O_(3) coatings during high temperature and thermal shock resistance were investigated.The results show that the micro structure of the Al_(2)O_(3)-Y_(2)O_(3)-TiO_(2) coating is more uniform than that of the Al_(2)O_(3)-Y_(2)O_(3) coating.Meanwhile,amorphous phase is formed in the two coatings.The Al_(2)O_(3)-Y_(2)O_(3)(-TiO_(2)) coatings were heat treated for 2 h at temperatures of 800,1000 and 1200℃,respectively.It is found that the microstructure and properties of the two coatings have no obvious change at 800℃.Some of the amorphous phase is crystallized at1000℃,and meanwhile Y_(2)O_(3) and Al_(2)O_(3) react to form YAG phase and YAM phase.At 1200℃,all of the amorphous phases are crystallized.After heat treatment,the micro hardness of the two coatings is increased.The thermal shock resistance of the Al_(2)O_(3)-Y_(2)O_(3) system coatings can be improved by using TC4 titanium alloy as substrate and with NiCrAlY bonding layer.Moreover,the Al_(2)O_(3)-Y_(2)O_(3)-TiO_(2) coating exhibits better thermal shock resistance due to the addition of TiO_(2).
基金supported by the National Key R&D Program of China(2021YFA1600202)the National Natural Science Foundation of China(U2032162,81972191,U1932158,and 81871085)+7 种基金Hefei Institutes of Physical Science Director’s Fund(BJPY2021B06)the Collaborative Innovation Program of Hefei Science Center of CAS(2022HSCCIP013)Anhui Provincial Natural Science Foundation(2208085J10)Hefei Municipal Natural Science Foundation(2021009)the Natural Science Foundation of Shandong Province(ZR2019LZL018)the High Magnetic Field Laboratory of Anhui Province(AHHM-FX-2021-04)the Project of China Postdoctoral Science Foundation(2019M652403)the Project of Postdoctoral Innovation of Shandong Province(202002048)。