Background:Prolonged sitting and reduced physical activity lead to low energy expenditures.However,little is known about the joint impact of daily sitting time and physical activity on body fat distribution.We investi...Background:Prolonged sitting and reduced physical activity lead to low energy expenditures.However,little is known about the joint impact of daily sitting time and physical activity on body fat distribution.We investigated the independent and joint associations of daily sitting time and physical activity with body fat among adults.Methods:This was a cross-sectional analysis of U.S.nationally representative data from the National Health and Nutrition Examination Survey2011-2018 among adults aged 20 years or older.Daily sitting time and leisure-time physical activity(LTPA)were self-reported using the Global Physical Activity Questionnaire.Body fat(total and trunk fat percentage)was determined via dual X-ray absorptiometry.Results:Among 10,808 adults,about 54.6%spent 6 h/day or more sitting;more than one-half reported no LTPA(inactive)or less than 150 min/week LTPA(insufficiently active)with only 43.3%reported 150 min/week or more LTPA(active)in the past week.After fully adjusting for sociodemographic data,lifestyle behaviors,and chronic conditions,prolonged sitting time and low levels of LTPA were associated with higher total and trunk fat percentages in both sexes.When stratifying by LTPA,the association between daily sitting time and body fat appeared to be stronger in those who were inactive/insuufficiently active.In the joint analyses,inactive/insuufficiently active adults who reported sitting more than 8 h/day had the highest total(female:3.99%(95%confidence interval(95%CI):3.09%-4.88%);male:3.79%(95%CI:2.75%-4.82%))and trunk body fat percentages(female:4.21%(95%CI:3.09%-5.32%);male:4.07%(95%CI:2.95%-5.19%))when compared with those who were active and sitting less than 4 h/day.Conclusion:Prolonged daily sitting time was associated with increased body fat among U.S.adults.The higher body fat associated with 6 h/day sitting may not be offset by achieving recommended levels of physical activity.展开更多
The clay mineralogy of 28 sandy-muddy transitional beach(SMT-Beach)sediments and surrounding mountain river sediments along the coasts of southeastern China was systematically investigated to reveal the sediment sourc...The clay mineralogy of 28 sandy-muddy transitional beach(SMT-Beach)sediments and surrounding mountain river sediments along the coasts of southeastern China was systematically investigated to reveal the sediment source-to-sink process variations of such beaches and their morphological indications.The results show that the clay mineral assemblages of these SMT-Beaches mainly comprise of almost equal illite(~30%),kaolinite(~28%),chlorite(~22%),and smectite(~20%)contents.From the surrounding mountain rivers to the SMT-Beaches,clay mineral assemblages show distinct spatial changes characterized by a large decrease(~40%)in kaolinite,whereas the other three clay minerals present relative increases,especially clear for smectite.The muddy sediment sources of SMT-Beaches inferred from the clay mineralogy are mainly derived from nearby mountain rivers coupled with long-distance transport and penetration of the Changjiang River.The sandy sediments of these beaches are predominantly sourced from nearby mountain rivers,the weathering products of surrounding rocks in both mainland and island environments,and erosion of the“Old Red Sand”and“Red Soil Platform”.However,the sandy sediment sources of the SMT-Beaches are largely reduced because of the remarkable decrease in the river fluvial supply associated with intensive human activities such as dam construction and coastal reclamation.Subsequently,the sandy sections of SMT-Beaches present clear erosion and have revealed by both time series remote sensing images and a compilation of published literature.In contrast,the muddy sediment supply of SMT-Beaches is temporarily stable and relatively constant,resulting in the landward migration of the mudflats with relative transgression or accumulation.These findings highlight that the natural evolution processes of SMT-Beaches have been greatly reshaped by intensive human activities.展开更多
As one of the main areas of tropical storm action in the northwestern Pacific Ocean,South China experiences several typhoons each year,and coastal erosion is a problem,making the area a natural testing ground for stud...As one of the main areas of tropical storm action in the northwestern Pacific Ocean,South China experiences several typhoons each year,and coastal erosion is a problem,making the area a natural testing ground for studying the dynamic geomorphological processes and storm response of promontory-straight coasts.This study is based on three years of topographic data and remote sensing imagery of Gulei Beach and uses topographic profile morphology,single width erosion-accretion and mean change,combined with the Coastsat model to quantify the seasonal and interannual variability and storm response of the beach and to explain the evolution of shoreline change and beach dynamics geomorphology in the last decade.Gulei Beach has been in a state of overall erosion and local accretion for a long time,with relatively obvious cyclical changes;seasonal changes are also obvious,which are mainly characterized by summer accretion and winter erosion,with accretion at the top of the bay and accretion and erosion on the north and south sides of the bay corner,respectively;the seasonal erosion-accretion volume of the beach profile ranges from-80 m3/m to 95.52 m3/m,and the interannual erosion-accretion volume ranges from-69.09 m3/m to 87.31 m3/m.The response of beaches to typhoons with different paths varies greatly depending on the length,slope,orientation and scale of beach development.The large and gently developing Futou beach is less responsive to storms,while the less developed headlands in the southern Gulei Peninsula are more susceptible to disturbance by external factors and respond more strongly to typhoons.Storm distance is more influential than storm intensity.Under the influence of human activities,obvious erosion hotspots develop during normal weather,but storm processes produce redistribution of beach material patterns,and erosion hotspots disappear after storms.The results of this study enrich the theory of beach dynamics geomorphology and provide technical support for disaster prevention and mitigation,as well as ecological restoration of coastal zones.展开更多
BACKGROUND: Although regulatory T cells(Tregs) are key to the maintenance of immunologic homeostasis and tolerance, little is known about Treg-mediated immunosuppression in the stage of sepsis. This article aimed to r...BACKGROUND: Although regulatory T cells(Tregs) are key to the maintenance of immunologic homeostasis and tolerance, little is known about Treg-mediated immunosuppression in the stage of sepsis. This article aimed to review the current literature on the role of Tregs in the pathophysiology of septic response, attempting to investigate the role of Tregs in immune dysfunction during sepsis.DATA SOURCES: A literature search was conducted in January 2014 using the China National Knowledge Infrastructure and Pub Med. Articles on the role of Tregs in immune dysfunction during sepsis were identified.RESULTS: The identified articles indicated that Treg levels can be used for the assessment of the course of sepsis. The inhibition of Treg activity can promote the recovery of immune function.CONCLUSION: Since the mechanism of Tregs is complex during the sepsis, more studies are needed.展开更多
Topological magnetic Weyl semimetals have been proposed to host controllable chiral domain walls which bear a great prospect in device applications. To exploit them in applications, it is important to have a proper wa...Topological magnetic Weyl semimetals have been proposed to host controllable chiral domain walls which bear a great prospect in device applications. To exploit them in applications, it is important to have a proper way to tune and manipulate these domain walls. One possible means is through magnetoelastic coupling. The involvement of rare earth in the lately proposed RAl X(R =rare earth, X = Si and Ge) family magnetic Weyl semimetals may provide such a platform. Here we present the transport and thermodynamic properties of Ce Al Ge under hydrostatic pressure. We find that pressure enhances the antiferromagnetic exchange in Ce Al Ge but essentially retains its magnetic structure. A large topological Hall effect with a pronounced loop shape is observed within the magnetically ordered state, and it splits into two regions under pressure. Such an unusual electromagnetic response is inferred to be a consequence of chiral magnetic domain walls. The unprecedented concomitance of its evolution under pressure and the reentrance of antiferromagnetic order strongly suggest the capability of switching on/off this electromagnetic response in noncentrosymmetric magnetic Weyl semimetals via magnetoelastic coupling.展开更多
Quasi-one-dimensional(Q1D) Cr-based pnictide K_(2)Cr_(3)As_(3)exhibits superconductivity probably with spin-triplet pairing. It is of fundamental importance to explore the parent compound from which superconductivity ...Quasi-one-dimensional(Q1D) Cr-based pnictide K_(2)Cr_(3)As_(3)exhibits superconductivity probably with spin-triplet pairing. It is of fundamental importance to explore the parent compound from which superconductivity emerges. Here we report the synthesis,crystal structure, physical properties, and density functional theory(DFT) calculations of(nearly) fully hydrogenized K_(2)Cr_(3)As_(3)H.It is found that the intercalation of hydrogen in K_(2)Cr_(3)As_(3)leads to absence of metallicity as well as superconductivity. An antiferromagnetic transition nearby room temperature is evidenced from the measurements of magnetic susceptibility and heat capacity.The antiferromagnetic insulating state can be reproduced by the DFT calculations, which show a novel non-collinear co-planar magnetic order. Our result sheds light on the mechanism of unconventional superconductivity in Q1D Cr-based superconductors.展开更多
Recently,CrAs based superconductors have attracted much attention.CrAs itself is a 3D antiferromagnet(AFM),which becomes superconducting(SC)under modest pressure with T_C^2 K[1].Subsequently,a new family of quasi-lD s...Recently,CrAs based superconductors have attracted much attention.CrAs itself is a 3D antiferromagnet(AFM),which becomes superconducting(SC)under modest pressure with T_C^2 K[1].Subsequently,a new family of quasi-lD superconductors A_2Cr_3As_3(A=K,Rb,Cs)has been discovered at ambient pressure with T_c up to 6.1 K[2-4].The key building block of展开更多
This paper proposes a high-resolution successive-approximation register(SAR) analog-to-digital converter(ADC) with sub-2 radix split-capacitor array architecture.The built-in redundancy of sub-2 radix architecture pro...This paper proposes a high-resolution successive-approximation register(SAR) analog-to-digital converter(ADC) with sub-2 radix split-capacitor array architecture.The built-in redundancy of sub-2 radix architecture provides additional information in the digital calibration based on offset double injection.The calibration method is simple in structure and fast in convergence.The correction of errors in each bit is independent of those in the previous bit.A split-capacitor array is used to reduce the total capacitance especially in a high-resolution SAR ADC.An offset signal is injected by the switching scheme of capacitor array to minimize the hardware overhead.The prototype of 0.18 μm CMOS process obtains 14.46 bit ENOB and 95.65 dB SFDR after calibration.With calibration,the INL and DNL are-0.813/0.938 and-0.625/0.688,respectively.展开更多
Using angle-resolved photoemission spectroscopy(ARPES) and low-energy electron diffraction(LEED), together with densityfunctional theory(DFT) calculation, we report the formation of charge density wave(CDW) and its in...Using angle-resolved photoemission spectroscopy(ARPES) and low-energy electron diffraction(LEED), together with densityfunctional theory(DFT) calculation, we report the formation of charge density wave(CDW) and its interplay with the Kondo effect and topological states in CeSbTe. The observed Fermi surface(FS) exhibits parallel segments that can be well connected by the observed CDWordering vector, indicating that the CDWorder is driven by the electron-phonon coupling(EPC) as a result of the nested FS. The CDW gap is large(~0.3 eV) and momentum-dependent, which naturally explains the robust CDWorder up to high temperatures. The gap opening leads to a reduced density of states(DOS) near the Fermi level(EF), which correspondingly suppresses the many-body Kondo effect, leading to very localized 4 f electrons at 20 K and above. The topological Dirac cone at the X point is found to remain gapless inside the CDW phase. Our results provide evidence for the competition between CDWand the Kondo effect in a Kondo lattice system. The robust CDWorder in CeSbTe and related compounds provide an opportunity to search for the long-sought-after axionic insulator.展开更多
We report the discovery of a new noncentrosymmetric superconductor CaPtAs.It crystallizes in a tetragonal structure(space group I41md,No.109),featuring three dimensional honeycomb networks of Pt-As and a much elongate...We report the discovery of a new noncentrosymmetric superconductor CaPtAs.It crystallizes in a tetragonal structure(space group I41md,No.109),featuring three dimensional honeycomb networks of Pt-As and a much elongated c-axis(a=b=4.18?,and c=43.70?).The superconductivity of CaPtAs with Tc=1.47 K was characterized by means of electrical resistivity,specific heat,and ac magnetic susceptibility.The electronic specific heat Ce(T)/T shows evidence for a deviation from the behavior of a conventional BCS superconductor,and can be reasonably fitted by a p-wave model.The upper critical fieldμ0Hc2 of CaPtAs exhibits a moderate anisotropy,with an in-plane value of around 204 mT and an out-of-plane value of 148 mT.Density functional theory calculations indicate that the Pt-5 d and As-4 p orbitals mainly contribute to the density of states near the Fermi level,showing that the Pt-As honeycomb networks may significantly influence the superconducting properties.展开更多
Anomalous Nernst effect, as a thermal partner of anomalous Hall effect, is particularly sensitive to the Berry curvature anomaly near the Fermi level, and has been used to probe the topological nature of quantum mater...Anomalous Nernst effect, as a thermal partner of anomalous Hall effect, is particularly sensitive to the Berry curvature anomaly near the Fermi level, and has been used to probe the topological nature of quantum materials. In this work, we report the observation of both effects in the ferromagnetic Weyl-semimetal Fe_(3-δ)GeTe_(2) with tunable Fe vacancies. With decreasing Fe vacancies,the anomalous Hall conductivity evolves as a function of the longitudinal conductivity from the hopping region to the region where the intrinsic Berry curvature contribution dominates. Concomitant evolutions in the anomalous Nernst signal and the anomalous off-diagonal thermoelectric coefficient are observed below the Curie temperature, displaying a unique sign change caused by the Fe vacancies. Combining these results with first-principles calculations, we argue that the Fe-vacancy concentration plays a unique role in simultaneously tuning the chemical potential and ferromagnetism, which in turn controls the Berry curvature contribution in this family of ferromagnetic topological semimetals.展开更多
We investigated the coexistence of superconductivity and antiferromagnetic order in the compound Er_(2)O_(2)Bi with anti-ThCr_(2)Si_(2)-type structure through resistivity,magnetization,specific heat measurements and f...We investigated the coexistence of superconductivity and antiferromagnetic order in the compound Er_(2)O_(2)Bi with anti-ThCr_(2)Si_(2)-type structure through resistivity,magnetization,specific heat measurements and first-principle calculations.The superconducting transition temperature Tc of 1.23 K and antiferromagnetic transition temperature TN of 3 K are observed in the sample with the best nominal composition.The superconducting upper critical field H_(c2)(0)and electron-phonon coupling constantλe−ph in Er_(2)O_(2)Bi are similar to those in the previously reported non-magnetic superconductor Y_(2)O_(2)Bi with the same structure,indicating that the superconductivity in Er_(2)O_(2)Bi may have the same origin as in Y_(2)O_(2)Bi.The first-principle calculations of Er_(2)O_(2)Bi show that the Fermi surface is mainly composed of the Bi 6p orbitals both in the paramagnetic and antiferromagnetic state,implying minor effect of the 4f electrons on the Fermi surface.Besides,upon increasing the oxygen incorporation in Er_(2)O_(x)Bi,Tc increases from 1 to 1.23 K and TN decreases slightly from 3 K to 2.96 K,revealing that superconductivity and antiferromagnetic order may compete with each other.The Hall effect measurements indicate that hole-type carrier density indeed increases with increasing oxygen content,which may account for the variations of Tc and TN with different oxygen content.展开更多
Dear Editor,ATP-binding cassette(ABC)-ATPase(RAD50),together with meiotic recombination 11 homolog 1(MRE11)subunits,to form MRE11-RAD50 complex,plays important roles in recognition of double-stranded DNA(dsDNA)and ini...Dear Editor,ATP-binding cassette(ABC)-ATPase(RAD50),together with meiotic recombination 11 homolog 1(MRE11)subunits,to form MRE11-RAD50 complex,plays important roles in recognition of double-stranded DNA(dsDNA)and initiation of consequent inflammatory cascade1.Acute lung injury(ALI)and acute respiratory destress syndrome(ARDS)are systemic uncontrolled inflammation and life-threatening.However,the function of the DNA sensor in ALI/ARDS remains poorly defined.Here we investigated functions of RAD50 using mouse primary macrophages and conditionally RAD50 knockout mice in vitro and in a lipopolysaccharide(LPS)-induced lung injury model.展开更多
Superconductivity in crystals without inversion symmetry has received extensive attention due to its unconventional pairing and possible nontrivial topological properties.Using first-principles calculations,we systemi...Superconductivity in crystals without inversion symmetry has received extensive attention due to its unconventional pairing and possible nontrivial topological properties.Using first-principles calculations,we systemically study the electronic structure of noncentrosymmetric superconductors A_(2)Cr_(3)As_(3)(A=Na,K,Rb,and Cs).展开更多
Rhodium-containing compounds offer a fertile playground to explore novel materials with superconductivity(SC)and other fantastic electronic correlation effects.A new ternary rhodium-antimonide La_(2)Rh_(3)+δSb_(4)(δ...Rhodium-containing compounds offer a fertile playground to explore novel materials with superconductivity(SC)and other fantastic electronic correlation effects.A new ternary rhodium-antimonide La_(2)Rh_(3)+δSb_(4)(δ≈1/8)has been synthesized by a Bi-flux method.It crystallizes in the orthorhombic La_(2)Rh_(3+δ)Sb_(4)-like structure,with the space group Pnma(No.62).The crystalline structure appears as stacking the two-dimensional RhSb_(4)-and RhSb_(5)-polyhedra networks along b axis,and the La atoms embed in the cavities of these networks.Band structure calculations confirm it as a multi-band metal with a van-Hove singularity like feature at the Fermi level,whose density of states are mainly of Rh-4d and Sb-5p characters.The calculations also imply that the redundant Rh acts as charge dopant.SC is observed in this material with onset transition at Ton c≈0.8 K.Ultra-low temperature magnetic susceptibility and specific heat measurements suggest that it is an s-wave type-II superconductor.Our work may also imply that the broad Ln_(2)Tm_(3+δ)Sb_(4)(Ln=rare earth,Tm=Rh,Ir)family may host new material bases where new superconductors,quantum magnetism and other electronic correlation effects could be found.展开更多
文摘Background:Prolonged sitting and reduced physical activity lead to low energy expenditures.However,little is known about the joint impact of daily sitting time and physical activity on body fat distribution.We investigated the independent and joint associations of daily sitting time and physical activity with body fat among adults.Methods:This was a cross-sectional analysis of U.S.nationally representative data from the National Health and Nutrition Examination Survey2011-2018 among adults aged 20 years or older.Daily sitting time and leisure-time physical activity(LTPA)were self-reported using the Global Physical Activity Questionnaire.Body fat(total and trunk fat percentage)was determined via dual X-ray absorptiometry.Results:Among 10,808 adults,about 54.6%spent 6 h/day or more sitting;more than one-half reported no LTPA(inactive)or less than 150 min/week LTPA(insufficiently active)with only 43.3%reported 150 min/week or more LTPA(active)in the past week.After fully adjusting for sociodemographic data,lifestyle behaviors,and chronic conditions,prolonged sitting time and low levels of LTPA were associated with higher total and trunk fat percentages in both sexes.When stratifying by LTPA,the association between daily sitting time and body fat appeared to be stronger in those who were inactive/insuufficiently active.In the joint analyses,inactive/insuufficiently active adults who reported sitting more than 8 h/day had the highest total(female:3.99%(95%confidence interval(95%CI):3.09%-4.88%);male:3.79%(95%CI:2.75%-4.82%))and trunk body fat percentages(female:4.21%(95%CI:3.09%-5.32%);male:4.07%(95%CI:2.95%-5.19%))when compared with those who were active and sitting less than 4 h/day.Conclusion:Prolonged daily sitting time was associated with increased body fat among U.S.adults.The higher body fat associated with 6 h/day sitting may not be offset by achieving recommended levels of physical activity.
基金The National Natural Science Foundation of China under contract Nos 41930538,42076211 and 42076058the Scientific Research Foundation of the Third Institute of Oceanography,Ministry of Natural Resources under contract Nos 2022017 and 2019006the China Postdoctoral Science Foundation under contract No.2019M652248.
文摘The clay mineralogy of 28 sandy-muddy transitional beach(SMT-Beach)sediments and surrounding mountain river sediments along the coasts of southeastern China was systematically investigated to reveal the sediment source-to-sink process variations of such beaches and their morphological indications.The results show that the clay mineral assemblages of these SMT-Beaches mainly comprise of almost equal illite(~30%),kaolinite(~28%),chlorite(~22%),and smectite(~20%)contents.From the surrounding mountain rivers to the SMT-Beaches,clay mineral assemblages show distinct spatial changes characterized by a large decrease(~40%)in kaolinite,whereas the other three clay minerals present relative increases,especially clear for smectite.The muddy sediment sources of SMT-Beaches inferred from the clay mineralogy are mainly derived from nearby mountain rivers coupled with long-distance transport and penetration of the Changjiang River.The sandy sediments of these beaches are predominantly sourced from nearby mountain rivers,the weathering products of surrounding rocks in both mainland and island environments,and erosion of the“Old Red Sand”and“Red Soil Platform”.However,the sandy sediment sources of the SMT-Beaches are largely reduced because of the remarkable decrease in the river fluvial supply associated with intensive human activities such as dam construction and coastal reclamation.Subsequently,the sandy sections of SMT-Beaches present clear erosion and have revealed by both time series remote sensing images and a compilation of published literature.In contrast,the muddy sediment supply of SMT-Beaches is temporarily stable and relatively constant,resulting in the landward migration of the mudflats with relative transgression or accumulation.These findings highlight that the natural evolution processes of SMT-Beaches have been greatly reshaped by intensive human activities.
基金The National Natural Science Foundation of China under contract Nos 42076058 and 41930538the National Key Research and Development Program of China under contract No.2022YFC3106104the Scientific Research Foundation of Third Institute of Oceanography,Ministry of Natural Resources under contract Nos 2023023 and 2019017。
文摘As one of the main areas of tropical storm action in the northwestern Pacific Ocean,South China experiences several typhoons each year,and coastal erosion is a problem,making the area a natural testing ground for studying the dynamic geomorphological processes and storm response of promontory-straight coasts.This study is based on three years of topographic data and remote sensing imagery of Gulei Beach and uses topographic profile morphology,single width erosion-accretion and mean change,combined with the Coastsat model to quantify the seasonal and interannual variability and storm response of the beach and to explain the evolution of shoreline change and beach dynamics geomorphology in the last decade.Gulei Beach has been in a state of overall erosion and local accretion for a long time,with relatively obvious cyclical changes;seasonal changes are also obvious,which are mainly characterized by summer accretion and winter erosion,with accretion at the top of the bay and accretion and erosion on the north and south sides of the bay corner,respectively;the seasonal erosion-accretion volume of the beach profile ranges from-80 m3/m to 95.52 m3/m,and the interannual erosion-accretion volume ranges from-69.09 m3/m to 87.31 m3/m.The response of beaches to typhoons with different paths varies greatly depending on the length,slope,orientation and scale of beach development.The large and gently developing Futou beach is less responsive to storms,while the less developed headlands in the southern Gulei Peninsula are more susceptible to disturbance by external factors and respond more strongly to typhoons.Storm distance is more influential than storm intensity.Under the influence of human activities,obvious erosion hotspots develop during normal weather,but storm processes produce redistribution of beach material patterns,and erosion hotspots disappear after storms.The results of this study enrich the theory of beach dynamics geomorphology and provide technical support for disaster prevention and mitigation,as well as ecological restoration of coastal zones.
基金supported by the National Natural Science Foundation of China(81170296)
文摘BACKGROUND: Although regulatory T cells(Tregs) are key to the maintenance of immunologic homeostasis and tolerance, little is known about Treg-mediated immunosuppression in the stage of sepsis. This article aimed to review the current literature on the role of Tregs in the pathophysiology of septic response, attempting to investigate the role of Tregs in immune dysfunction during sepsis.DATA SOURCES: A literature search was conducted in January 2014 using the China National Knowledge Infrastructure and Pub Med. Articles on the role of Tregs in immune dysfunction during sepsis were identified.RESULTS: The identified articles indicated that Treg levels can be used for the assessment of the course of sepsis. The inhibition of Treg activity can promote the recovery of immune function.CONCLUSION: Since the mechanism of Tregs is complex during the sepsis, more studies are needed.
基金supported by the Key R&D Program of Zhejiang Province,China(2021C01002)the National Natural Science Foundation of China(11874320,12034017,11874137,and 11974306)+1 种基金the National Key R&D Program of China(2017YFA0303100)Zhejiang Provincial Natural Science Foundation of China(R22A0410240).
基金supported by the Open Research Fund of Songshan Lake Materials Laboratory(Grant No.2022SLABFN27)National Natural Science Foundation of China(Grant Nos.12274364,and U1932155)+3 种基金Fundamental Research Funds for the Central Universities of China(Grant No.2019kfy XMBZ071)National Key R&D Program of China(Grant No.2022YFA1602602)Guangdong Basic and Applied Basic Research Foundation(Grant No.2022B1515120020)Pioneer and Leading Goose R&D Program of Zhejiang(Grant No.2022SDXHDX0005)。
文摘Topological magnetic Weyl semimetals have been proposed to host controllable chiral domain walls which bear a great prospect in device applications. To exploit them in applications, it is important to have a proper way to tune and manipulate these domain walls. One possible means is through magnetoelastic coupling. The involvement of rare earth in the lately proposed RAl X(R =rare earth, X = Si and Ge) family magnetic Weyl semimetals may provide such a platform. Here we present the transport and thermodynamic properties of Ce Al Ge under hydrostatic pressure. We find that pressure enhances the antiferromagnetic exchange in Ce Al Ge but essentially retains its magnetic structure. A large topological Hall effect with a pronounced loop shape is observed within the magnetically ordered state, and it splits into two regions under pressure. Such an unusual electromagnetic response is inferred to be a consequence of chiral magnetic domain walls. The unprecedented concomitance of its evolution under pressure and the reentrance of antiferromagnetic order strongly suggest the capability of switching on/off this electromagnetic response in noncentrosymmetric magnetic Weyl semimetals via magnetoelastic coupling.
基金supported by the Key Research and Development Program of Zhejiang Province,China(Grant No.2021C01002)the National Natural Science Foundation of China(Grant Nos.12050003,and 11674281)。
文摘Quasi-one-dimensional(Q1D) Cr-based pnictide K_(2)Cr_(3)As_(3)exhibits superconductivity probably with spin-triplet pairing. It is of fundamental importance to explore the parent compound from which superconductivity emerges. Here we report the synthesis,crystal structure, physical properties, and density functional theory(DFT) calculations of(nearly) fully hydrogenized K_(2)Cr_(3)As_(3)H.It is found that the intercalation of hydrogen in K_(2)Cr_(3)As_(3)leads to absence of metallicity as well as superconductivity. An antiferromagnetic transition nearby room temperature is evidenced from the measurements of magnetic susceptibility and heat capacity.The antiferromagnetic insulating state can be reproduced by the DFT calculations, which show a novel non-collinear co-planar magnetic order. Our result sheds light on the mechanism of unconventional superconductivity in Q1D Cr-based superconductors.
基金supported in part by the National Key R&D Program of China (2016YFA0300202)the National Basic Research Program of China (2014CB921201 and 2014CB921203)+1 种基金the National Natural Science Foundation of China (11374256, 11274269 and 11274006)the Natural Science Foundation of Zhejiang Province (LR12A04003)
文摘Recently,CrAs based superconductors have attracted much attention.CrAs itself is a 3D antiferromagnet(AFM),which becomes superconducting(SC)under modest pressure with T_C^2 K[1].Subsequently,a new family of quasi-lD superconductors A_2Cr_3As_3(A=K,Rb,Cs)has been discovered at ambient pressure with T_c up to 6.1 K[2-4].The key building block of
基金the National Key R&D Program of China(2017YFA0303100,and 2016YFA0300202)the National Natural Science Foundation of China(12034017,U1632275,and 11974306)+2 种基金the Science Challenge Project of China(TZ2016004)the Key R&D Program of Zhejiang Province(2021C01002)supported by the National Science Foundation Cooperative Agreement No.DMR-1644779 and the State of Florida。
文摘This paper proposes a high-resolution successive-approximation register(SAR) analog-to-digital converter(ADC) with sub-2 radix split-capacitor array architecture.The built-in redundancy of sub-2 radix architecture provides additional information in the digital calibration based on offset double injection.The calibration method is simple in structure and fast in convergence.The correction of errors in each bit is independent of those in the previous bit.A split-capacitor array is used to reduce the total capacitance especially in a high-resolution SAR ADC.An offset signal is injected by the switching scheme of capacitor array to minimize the hardware overhead.The prototype of 0.18 μm CMOS process obtains 14.46 bit ENOB and 95.65 dB SFDR after calibration.With calibration,the INL and DNL are-0.813/0.938 and-0.625/0.688,respectively.
基金supported by the National Key R&D Program of the Ministry of Science and Technology of China (Grant Nos. 2016YFA0300203, and 2017YFA0303100)the National Science Foundation of China (Grant Nos. 11674280, and 11774305)+1 种基金the Science Challenge Program of ChinaPart of this research used Beam line 03U of the Shanghai Synchrotron Radiation Facility, which was supported by ME2 Project (Grant No. 11227902) from the National Natural Science Foundation of China。
文摘Using angle-resolved photoemission spectroscopy(ARPES) and low-energy electron diffraction(LEED), together with densityfunctional theory(DFT) calculation, we report the formation of charge density wave(CDW) and its interplay with the Kondo effect and topological states in CeSbTe. The observed Fermi surface(FS) exhibits parallel segments that can be well connected by the observed CDWordering vector, indicating that the CDWorder is driven by the electron-phonon coupling(EPC) as a result of the nested FS. The CDW gap is large(~0.3 eV) and momentum-dependent, which naturally explains the robust CDWorder up to high temperatures. The gap opening leads to a reduced density of states(DOS) near the Fermi level(EF), which correspondingly suppresses the many-body Kondo effect, leading to very localized 4 f electrons at 20 K and above. The topological Dirac cone at the X point is found to remain gapless inside the CDW phase. Our results provide evidence for the competition between CDWand the Kondo effect in a Kondo lattice system. The robust CDWorder in CeSbTe and related compounds provide an opportunity to search for the long-sought-after axionic insulator.
基金the National Key R&D Program of China(Grant Nos.2016YFA0300202,and 2017YFA0303100)the National Natural Science Foundation of China(Grant Nos.U1632275,and 11874320)+1 种基金the Science Challenge Project of China(Grant No.TZ2016004)the Fundamental Research Funds for the Central Universities.
文摘We report the discovery of a new noncentrosymmetric superconductor CaPtAs.It crystallizes in a tetragonal structure(space group I41md,No.109),featuring three dimensional honeycomb networks of Pt-As and a much elongated c-axis(a=b=4.18?,and c=43.70?).The superconductivity of CaPtAs with Tc=1.47 K was characterized by means of electrical resistivity,specific heat,and ac magnetic susceptibility.The electronic specific heat Ce(T)/T shows evidence for a deviation from the behavior of a conventional BCS superconductor,and can be reasonably fitted by a p-wave model.The upper critical fieldμ0Hc2 of CaPtAs exhibits a moderate anisotropy,with an in-plane value of around 204 mT and an out-of-plane value of 148 mT.Density functional theory calculations indicate that the Pt-5 d and As-4 p orbitals mainly contribute to the density of states near the Fermi level,showing that the Pt-As honeycomb networks may significantly influence the superconducting properties.
基金the National Key R&D Program of the China(2016YFA0300402,2014CB648400,and 2016YFA0300203)the National Natural Science Foundation of China(11774305 and 11274006)the Fundamental Research Funds for the Central Universities of China。
基金supported by the National Natural Science Foundation of China (Grant Nos. U1932155, 11874136, 11874137, and U19A2093)the National Key Projects for Research and Development of China (Grant No. 2019YFA0308602)+1 种基金the Key R&D Program of Zhejiang Province China (Grant No. 2021C01002)supported by an open program from Wuhan National High Magnetic Field Center (Grant No. 2016KF03)。
文摘Anomalous Nernst effect, as a thermal partner of anomalous Hall effect, is particularly sensitive to the Berry curvature anomaly near the Fermi level, and has been used to probe the topological nature of quantum materials. In this work, we report the observation of both effects in the ferromagnetic Weyl-semimetal Fe_(3-δ)GeTe_(2) with tunable Fe vacancies. With decreasing Fe vacancies,the anomalous Hall conductivity evolves as a function of the longitudinal conductivity from the hopping region to the region where the intrinsic Berry curvature contribution dominates. Concomitant evolutions in the anomalous Nernst signal and the anomalous off-diagonal thermoelectric coefficient are observed below the Curie temperature, displaying a unique sign change caused by the Fe vacancies. Combining these results with first-principles calculations, we argue that the Fe-vacancy concentration plays a unique role in simultaneously tuning the chemical potential and ferromagnetism, which in turn controls the Berry curvature contribution in this family of ferromagnetic topological semimetals.
基金This work was supported by the National Key R&D Projects of China(Grant Nos.2019YFA0308602 and 2016YFA0300402)the National Natural Science Foundation of China(Grant No.11774305)the Fundamental Research Funds for the Central Universities of China.
文摘We investigated the coexistence of superconductivity and antiferromagnetic order in the compound Er_(2)O_(2)Bi with anti-ThCr_(2)Si_(2)-type structure through resistivity,magnetization,specific heat measurements and first-principle calculations.The superconducting transition temperature Tc of 1.23 K and antiferromagnetic transition temperature TN of 3 K are observed in the sample with the best nominal composition.The superconducting upper critical field H_(c2)(0)and electron-phonon coupling constantλe−ph in Er_(2)O_(2)Bi are similar to those in the previously reported non-magnetic superconductor Y_(2)O_(2)Bi with the same structure,indicating that the superconductivity in Er_(2)O_(2)Bi may have the same origin as in Y_(2)O_(2)Bi.The first-principle calculations of Er_(2)O_(2)Bi show that the Fermi surface is mainly composed of the Bi 6p orbitals both in the paramagnetic and antiferromagnetic state,implying minor effect of the 4f electrons on the Fermi surface.Besides,upon increasing the oxygen incorporation in Er_(2)O_(x)Bi,Tc increases from 1 to 1.23 K and TN decreases slightly from 3 K to 2.96 K,revealing that superconductivity and antiferromagnetic order may compete with each other.The Hall effect measurements indicate that hole-type carrier density indeed increases with increasing oxygen content,which may account for the variations of Tc and TN with different oxygen content.
基金The authors are grateful for financial support from the National Natural Science Foundation of China(81870007,81920108001,81800024,81900025,81870023,81700025)the Zhejiang Provincial Natural Science Foundation(LD19H160001)the Zhejiang Provincial Program for the Cultivation of High-Level Innovative Health Talents(2016-63).
文摘Dear Editor,ATP-binding cassette(ABC)-ATPase(RAD50),together with meiotic recombination 11 homolog 1(MRE11)subunits,to form MRE11-RAD50 complex,plays important roles in recognition of double-stranded DNA(dsDNA)and initiation of consequent inflammatory cascade1.Acute lung injury(ALI)and acute respiratory destress syndrome(ARDS)are systemic uncontrolled inflammation and life-threatening.However,the function of the DNA sensor in ALI/ARDS remains poorly defined.Here we investigated functions of RAD50 using mouse primary macrophages and conditionally RAD50 knockout mice in vitro and in a lipopolysaccharide(LPS)-induced lung injury model.
基金This work has been supported by the NSFC(Nos.11874137,11574265,and 11774309)the 973 project(Nos.2014CB648400 and 2016YFA0300402).
文摘Superconductivity in crystals without inversion symmetry has received extensive attention due to its unconventional pairing and possible nontrivial topological properties.Using first-principles calculations,we systemically study the electronic structure of noncentrosymmetric superconductors A_(2)Cr_(3)As_(3)(A=Na,K,Rb,and Cs).
基金This work was supported by the open research fund of Songshan Lake Materials Laboratory(2022SLABFN27)NSF of China(Grants Nos.12004270,51861135104,11574097,12204298,12274364 and 11874137)+2 种基金the Fundamental Research Funds for the Central Universities of China(2019kfyXMBZ071)Guangdong Basic and Applied Basic Research Foundation(2019A1515110517)the Pioneer and Leading Goose R&D Program of Zhejiang(2022SDXHDX0005).
文摘Rhodium-containing compounds offer a fertile playground to explore novel materials with superconductivity(SC)and other fantastic electronic correlation effects.A new ternary rhodium-antimonide La_(2)Rh_(3)+δSb_(4)(δ≈1/8)has been synthesized by a Bi-flux method.It crystallizes in the orthorhombic La_(2)Rh_(3+δ)Sb_(4)-like structure,with the space group Pnma(No.62).The crystalline structure appears as stacking the two-dimensional RhSb_(4)-and RhSb_(5)-polyhedra networks along b axis,and the La atoms embed in the cavities of these networks.Band structure calculations confirm it as a multi-band metal with a van-Hove singularity like feature at the Fermi level,whose density of states are mainly of Rh-4d and Sb-5p characters.The calculations also imply that the redundant Rh acts as charge dopant.SC is observed in this material with onset transition at Ton c≈0.8 K.Ultra-low temperature magnetic susceptibility and specific heat measurements suggest that it is an s-wave type-II superconductor.Our work may also imply that the broad Ln_(2)Tm_(3+δ)Sb_(4)(Ln=rare earth,Tm=Rh,Ir)family may host new material bases where new superconductors,quantum magnetism and other electronic correlation effects could be found.
