Two-dimensional materials with high-temperature ferromagnetism and half-metallicity have the latest applications in spintronic devices.Based on first-principles calculations,we have investigated a novel two-dimensiona...Two-dimensional materials with high-temperature ferromagnetism and half-metallicity have the latest applications in spintronic devices.Based on first-principles calculations,we have investigated a novel two-dimensional CrS_(2) phase with an orthorhombic lattice.Our results suggest that it is stable in dynamics,thermodynamics,and mechanics.The ground state of monolayer orthorhombic CrS_(2) is both ferromagnetic and half-metallic,with a high Curie temperature of 895 K and a large spin-flipping gap on values of 0.804 eV.This room-temperature ferromagnetism and halfmetallicity can maintain stability against a strong biaxial strain ranging from–5%to 5%.Meanwhile,increasing strain can significantly maintain the out-of-plane magnetic anisotropy.A density of states analysis,together with the orbital-resolved magnetic anisotropy energy,has revealed that the strain-enhanced MAE is highly related to the 3d-orbital splitting of Cr atoms.Our results suggest the monolayer orthorhombic CrS_(2) is an ideal candidate for future spintronics.展开更多
The development of superconducting joining technology for reacted magnesium diboride(MgB_(2))conductors remains a critical challenge for the advancement of cryogen-free MgB_(2)-based magnets for magnetic resonance ima...The development of superconducting joining technology for reacted magnesium diboride(MgB_(2))conductors remains a critical challenge for the advancement of cryogen-free MgB_(2)-based magnets for magnetic resonance imaging(MRI).Herein,the fabrication of superconducting joints using reacted carbon-doped multifilament MgB_(2)wires for MRI magnets is reported.To achieve successful superconducting joints,the powder-in-mold method was employed,which involved tuning the filament protection mechanism,the powder compaction pressure,and the heat treatment condition.The fabricated joints demonstrated clear superconducting-to-normal transitions in self-field,with effective magnetic field screening up to 0.5 T at 20 K.To evaluate the interface between one of the MgB_(2)filaments and the MgB_(2)bulk within the joint,serial sectioning was conducted for the first time in this type of superconducting joint.The serial sectioning revealed space formation at the interface,potentially caused by the volume shrinkage associated with the MgB_(2)formation or the combined effect of the volume shrinkage and the different thermal expansion coefficients of the MgB_(2)bulk,the filament,the mold,and the sealing material.These findings are expected to be pivotal in developing MgB_(2)superconducting joining technology for MRI magnet applications through interface engineering.展开更多
BACKGROUND Cognitive dysfunction is the main manifestation of central neuropathy.Although cognitive impairments tend to be overlooked in patients with diabetes mellitus(DM),there is a growing body of evidence linking ...BACKGROUND Cognitive dysfunction is the main manifestation of central neuropathy.Although cognitive impairments tend to be overlooked in patients with diabetes mellitus(DM),there is a growing body of evidence linking DM to cognitive dysfunction.Hyperglycemia is closely related to neurological abnormalities,while often disregarded in clinical practice.Changes in cerebral neurotransmitter levels are associated with a variety of neurological abnormalities and may be closely related to blood glucose control in patients with type 2 DM(T2DM).AIM To evaluate the concentrations of cerebral neurotransmitters in T2DM patients exhibiting different hemoglobin A1c(HbA1c)levels.METHODS A total of 130 T2DM patients were enrolled at the Department of Endocrinology of Shanghai East Hospital.The participants were divided into four groups according to their HbA1c levels using the interquartile method,namely Q1(<7.875%),Q2(7.875%-9.050%),Q3(9.050%-11.200%)and Q4(≥11.200%).Clinical data were collected and measured,including age,height,weight,neck/waist/hip circumferences,blood pressure,comorbidities,duration of DM,and biochemical indicators.Meanwhile,neurotransmitters in the left hippocampus and left brainstem area were detected by proton magnetic resonance spectroscopy.RESULTS The HbA1c level was significantly associated with urinary microalbumin(mALB),triglyceride,low-density lipoprotein cholesterol(LDL-C),homeostasis model assessment of insulin resistance(HOMA-IR),and beta cell function(HOMA-β),N-acetylaspartate/creatine(NAA/Cr),and NAA/choline(NAA/Cho).Spearman correlation analysis showed that mALB,LDL-C,HOMA-IR and NAA/Cr in the left brainstem area were positively correlated with the level of HbA1c(P<0.05),whereas HOMA-βwas negatively correlated with the HbA1c level(P<0.05).Ordered multiple logistic regression analysis showed that NAA/Cho[Odds ratio(OR):1.608,95%confidence interval(95%CI):1.004-2.578,P<0.05],LDL-C(OR:1.627,95%CI:1.119-2.370,P<0.05),and HOMA-IR(OR:1.107,95%CI:1.031-1.188,P<0.01)were independent predictors of poor glycemic control.CONCLUSION The cerebral neurotransmitter concentrations in the left brainstem area in patients with T2DM are closely related to glycemic control,which may be the basis for the changes in cognitive function in diabetic patients.展开更多
TiO_(2)is the dominant and most widely researched photocatalyst for environmental remediation,however,the drawbacks,such as only responding to UV light(<5%of sunlight),low charge separation efficiency,and difficult...TiO_(2)is the dominant and most widely researched photocatalyst for environmental remediation,however,the drawbacks,such as only responding to UV light(<5%of sunlight),low charge separation efficiency,and difficulties in recycling,have severely hindered its practical application.Herein,we synthesized magnetically separable Fe_(3)O_(4)@MoS_(2)@mesoporous TiO_(2)(FMmT)photocatalysts via a simple,green,and template-free solvothermal method combined with ultrasonic hydrolysis.It is found that FMmT possesses a high specific surface area(55.09 m2·g−1),enhanced visible-light responsiveness(~521 nm),and remarkable photogenerated charge separation efficiency.In addition,the photocatalytic degradation efficiencies of FMmT for methylene blue(MB),rhodamine B(RhB),and tetracycline(TC)are 99.4%,98.5%,and 89.3%within 300 min,respectively.The corresponding degradation rates are 4.5,4.3,and 3.1 times higher than those of pure TiO_(2)separately.Owing to the high saturation magnetization(43.1 A·m^(2)·kg^(−1)),FMmT can achieve effective recycling with an applied magnetic field.The improved photocatalytic activity is closely related to the effective transport of photogenerated electrons by the active interlayer MoS_(2) and the electron–hole separation caused by the MoS_(2)@TiO_(2)heterojunction.Meanwhile,the excellent light-harvesting ability and abundant reactive sites of the mesoporous TiO_(2)shell further boost the photocatalytic efficiency of FMmT.This work provides a new approach and some experimental basis for the design and performance improvement of magnetic photocatalysts by innovatively incorporating MoS2 as the active interlayer and integrating it with a mesoporous shell.展开更多
The effects of CeO_(2)doping on the magnetic properties and microstructure of 2:17 type SmCo magnets are studied.With the increase of CeO_(2)from 0 wt.%to 3 wt.%,the coercivity of the magnets increases from 22.22 kOe ...The effects of CeO_(2)doping on the magnetic properties and microstructure of 2:17 type SmCo magnets are studied.With the increase of CeO_(2)from 0 wt.%to 3 wt.%,the coercivity of the magnets increases from 22.22 kOe to over 29.37 kOe,which is an increase of more than 30%.When the doping content is lower than 1 wt.%,the remanence and magnetic energy product of the magnets remain almost constant.Both decrease sharply as the doping concentration further increases.After CeO_(2)doping,the oxide content in the magnet increases significantly and the Ce element is uniformly distributed in the magnet.Observing the magnetic domains reveals that doping with CeO_(2)can refine the magnetic domains and make the magnetic domain wall more stable,resulting in a significant increase in the coercivity of the magnets.展开更多
We report the successful growth and characterization of Li_9Cr_3(P_2O_7)_3(PO_4)_2single crystal,and investigate its magnetic properties under external magnetic fields via magnetization and heat capacity measurements....We report the successful growth and characterization of Li_9Cr_3(P_2O_7)_3(PO_4)_2single crystal,and investigate its magnetic properties under external magnetic fields via magnetization and heat capacity measurements.Our study reveals that Li_9Cr_3(P_2O_7)_3(PO_4)_2 is an easy-plane kagome ferromagnet with S=3/2,as evidenced by the Curie–Weiss temperature of 6 K which implies a ferromagnetic exchange coupling in the material.Under zero magnetic field,Li_9Cr_3(P_2O_7)_3(PO_4)_2 undergoes a magnetic transition at TC=2.7 K from a paramagnetic state to a ferromagnetically ordered state with the magnetic moment lying in the kagome plane.By applying a c-axis directional magnetic field to rotate the spin alignment from the kagome plane to the c-axis,we observe a reduction in the magnetic transition temperature as the field is increased.We construct a magnetic phase diagram as a function of temperature and magnetic field applied parallel to the c-axis of Li_9Cr_3(P_2O_7)_3(PO_4)_2 and find that the phase boundary is linear over a certain temperature range.Regarding that theoretically,the field-induced phase transition of the spin reorientation in the easy-plane ferromagnet can be viewed as the ferromagnetic magnon Bose–Einstein condensation(BEC),the phase boundary scaling of field-induced(B c)magnetic transition in Li_9Cr_3(P_2O_7)_3(PO_4)_2 can be described as the quasi-2D magnon BEC,which has been observed in other ferromagnetic materials such as K_2CuF_4.展开更多
Two-dimensional(2D)nanomaterials with bipolar magnetism show great promise in spintronic applications.Manipulating carriers'spin-polarized orientation in bipolar magnetic semiconductor(BMS)requires a gate voltage,...Two-dimensional(2D)nanomaterials with bipolar magnetism show great promise in spintronic applications.Manipulating carriers'spin-polarized orientation in bipolar magnetic semiconductor(BMS)requires a gate voltage,but that is volatile.Recently,a new method has been proposed to solve the problem of volatility by introducing a ferroelectric gate with proper band alignment.In this paper,we predict that the PdX_(2)(X=F,Cl,Br,I)monolayers are 2D ferromagnetic BMS with dynamic stability,thermal stability,and mechanical stability by first-principles calculations.The critical temperatures are higher than the boiling point of liquid nitrogen and the BMS characteristics are robust against external strains and electric fields for PdCl_(2) and PdBr_(2).Then,we manipulate the spin-polarization of PdCl_(2) and PdBr_(2) by introducing a ferroelectric gate to enable magnetic half-metal/semiconductor switching and spin-up/down polarization switching control.Two kinds of spin devices(multiferroic memory and spin filter)have been proposed to realize the spin-polarized directions of electrons.These results demonstrate that PdCl_(2) and PdBr_(2) with BMS characters can be widely used as a general material structure for spintronic devices.展开更多
基金This work was financially supported by the Key Project of the Natural Science Program of Xinjiang Uygur Autonomous Region(Grant No.2013D01D03)the National Natural Science Foundation of China(Grant Nos.52073308 and 12004439)+5 种基金the Central South University Research Fund for Sheng Hua Scholars(Grant No.502033019)Hunan Provincial Innovation Foundation for Postgraduate(Grant No.CX20190107)the State Key Laboratory of Powder Metallurgy at Central South University,the Fundamental Research Funds for the Central Universities of Central South University,the Tianchi-Talent Project for Young Doctors of Xinjiang Uygur Autonomous Region(No.51052300570)the National Science Foundation of Hunan Province(No.2021JJ30864)the Key Project of the Natural Science Program of Xinjiang Uygur Autonomous Region(Grant No.2023D01D03)the Outstanding Doctoral Student Innovation Project of Xinjiang University(No.XJU2023BS028).
文摘Two-dimensional materials with high-temperature ferromagnetism and half-metallicity have the latest applications in spintronic devices.Based on first-principles calculations,we have investigated a novel two-dimensional CrS_(2) phase with an orthorhombic lattice.Our results suggest that it is stable in dynamics,thermodynamics,and mechanics.The ground state of monolayer orthorhombic CrS_(2) is both ferromagnetic and half-metallic,with a high Curie temperature of 895 K and a large spin-flipping gap on values of 0.804 eV.This room-temperature ferromagnetism and halfmetallicity can maintain stability against a strong biaxial strain ranging from–5%to 5%.Meanwhile,increasing strain can significantly maintain the out-of-plane magnetic anisotropy.A density of states analysis,together with the orbital-resolved magnetic anisotropy energy,has revealed that the strain-enhanced MAE is highly related to the 3d-orbital splitting of Cr atoms.Our results suggest the monolayer orthorhombic CrS_(2) is an ideal candidate for future spintronics.
基金the Japan Society for the Promotion of Science(JSPS)KAKENHI Grant Number JP18F18714Cryogenic Station,Research Network and Facility Services Division,National Institute for Materials Science(NIMS),Japansupported by the ARC Linkage Project(LP200200689)。
文摘The development of superconducting joining technology for reacted magnesium diboride(MgB_(2))conductors remains a critical challenge for the advancement of cryogen-free MgB_(2)-based magnets for magnetic resonance imaging(MRI).Herein,the fabrication of superconducting joints using reacted carbon-doped multifilament MgB_(2)wires for MRI magnets is reported.To achieve successful superconducting joints,the powder-in-mold method was employed,which involved tuning the filament protection mechanism,the powder compaction pressure,and the heat treatment condition.The fabricated joints demonstrated clear superconducting-to-normal transitions in self-field,with effective magnetic field screening up to 0.5 T at 20 K.To evaluate the interface between one of the MgB_(2)filaments and the MgB_(2)bulk within the joint,serial sectioning was conducted for the first time in this type of superconducting joint.The serial sectioning revealed space formation at the interface,potentially caused by the volume shrinkage associated with the MgB_(2)formation or the combined effect of the volume shrinkage and the different thermal expansion coefficients of the MgB_(2)bulk,the filament,the mold,and the sealing material.These findings are expected to be pivotal in developing MgB_(2)superconducting joining technology for MRI magnet applications through interface engineering.
基金Supported by the Academic Leaders Training Program of Pudong Health Bureau of Shanghai,No.PWRd2023-03Clinical Research Fund of Shanghai Municipal Commission of Health,No.202040136+1 种基金National Natural Science Foundation of China,No.82070842Jiangxi Health Commission Science and Technology Plan Project,No.202212838 and No.202212852.
文摘BACKGROUND Cognitive dysfunction is the main manifestation of central neuropathy.Although cognitive impairments tend to be overlooked in patients with diabetes mellitus(DM),there is a growing body of evidence linking DM to cognitive dysfunction.Hyperglycemia is closely related to neurological abnormalities,while often disregarded in clinical practice.Changes in cerebral neurotransmitter levels are associated with a variety of neurological abnormalities and may be closely related to blood glucose control in patients with type 2 DM(T2DM).AIM To evaluate the concentrations of cerebral neurotransmitters in T2DM patients exhibiting different hemoglobin A1c(HbA1c)levels.METHODS A total of 130 T2DM patients were enrolled at the Department of Endocrinology of Shanghai East Hospital.The participants were divided into four groups according to their HbA1c levels using the interquartile method,namely Q1(<7.875%),Q2(7.875%-9.050%),Q3(9.050%-11.200%)and Q4(≥11.200%).Clinical data were collected and measured,including age,height,weight,neck/waist/hip circumferences,blood pressure,comorbidities,duration of DM,and biochemical indicators.Meanwhile,neurotransmitters in the left hippocampus and left brainstem area were detected by proton magnetic resonance spectroscopy.RESULTS The HbA1c level was significantly associated with urinary microalbumin(mALB),triglyceride,low-density lipoprotein cholesterol(LDL-C),homeostasis model assessment of insulin resistance(HOMA-IR),and beta cell function(HOMA-β),N-acetylaspartate/creatine(NAA/Cr),and NAA/choline(NAA/Cho).Spearman correlation analysis showed that mALB,LDL-C,HOMA-IR and NAA/Cr in the left brainstem area were positively correlated with the level of HbA1c(P<0.05),whereas HOMA-βwas negatively correlated with the HbA1c level(P<0.05).Ordered multiple logistic regression analysis showed that NAA/Cho[Odds ratio(OR):1.608,95%confidence interval(95%CI):1.004-2.578,P<0.05],LDL-C(OR:1.627,95%CI:1.119-2.370,P<0.05),and HOMA-IR(OR:1.107,95%CI:1.031-1.188,P<0.01)were independent predictors of poor glycemic control.CONCLUSION The cerebral neurotransmitter concentrations in the left brainstem area in patients with T2DM are closely related to glycemic control,which may be the basis for the changes in cognitive function in diabetic patients.
基金financially supported by the National Key R & D Projects (Nos. 2021YFC1910504, 2019YFC1907101, 2019YFC1907103, and 2017YFB0702304)the Key R & D Project in Ningxia Hui Autonomous Region, China (No. 2020BCE01001)+6 种基金the Key and Normal Projects National Natural Science Foundation of China (Nos. U2002212 and 51672024)the Xijiang Innovation and Entrepreneurship Team (No. 2017A0109004)the Fundamental Research Funds for the Central Universities (Nos. FRF-BD-20-24A, FRF-TP-20-031A1, FRF-IC-19-017Z, FRF-GF-19-032B, and 06500141)the Integration of Green Key Process Systems MIIT, Natural Science Foundation of Beijing Municipality (No. 2214073)the Guangdong Basic and Applied Research Foundation, China (No. 2020A1515110408)the Foshan Science and Technology Innovation Special Foundation, China (No. BK21BE002)the Postdoctor Research Foundation of Shunde Graduate School of University of Science and Technology Beijing (No. 2020BH004)
文摘TiO_(2)is the dominant and most widely researched photocatalyst for environmental remediation,however,the drawbacks,such as only responding to UV light(<5%of sunlight),low charge separation efficiency,and difficulties in recycling,have severely hindered its practical application.Herein,we synthesized magnetically separable Fe_(3)O_(4)@MoS_(2)@mesoporous TiO_(2)(FMmT)photocatalysts via a simple,green,and template-free solvothermal method combined with ultrasonic hydrolysis.It is found that FMmT possesses a high specific surface area(55.09 m2·g−1),enhanced visible-light responsiveness(~521 nm),and remarkable photogenerated charge separation efficiency.In addition,the photocatalytic degradation efficiencies of FMmT for methylene blue(MB),rhodamine B(RhB),and tetracycline(TC)are 99.4%,98.5%,and 89.3%within 300 min,respectively.The corresponding degradation rates are 4.5,4.3,and 3.1 times higher than those of pure TiO_(2)separately.Owing to the high saturation magnetization(43.1 A·m^(2)·kg^(−1)),FMmT can achieve effective recycling with an applied magnetic field.The improved photocatalytic activity is closely related to the effective transport of photogenerated electrons by the active interlayer MoS_(2) and the electron–hole separation caused by the MoS_(2)@TiO_(2)heterojunction.Meanwhile,the excellent light-harvesting ability and abundant reactive sites of the mesoporous TiO_(2)shell further boost the photocatalytic efficiency of FMmT.This work provides a new approach and some experimental basis for the design and performance improvement of magnetic photocatalysts by innovatively incorporating MoS2 as the active interlayer and integrating it with a mesoporous shell.
基金the National Key R&D Program of China(Grant No.2021YFB3503102)the Zhejiang Provincial Key R&D Program of China(Grant No.2021C01191)the Science and Technology Innovation 2025 Major Project of Ningbo(Grant No.2020Z037)。
文摘The effects of CeO_(2)doping on the magnetic properties and microstructure of 2:17 type SmCo magnets are studied.With the increase of CeO_(2)from 0 wt.%to 3 wt.%,the coercivity of the magnets increases from 22.22 kOe to over 29.37 kOe,which is an increase of more than 30%.When the doping content is lower than 1 wt.%,the remanence and magnetic energy product of the magnets remain almost constant.Both decrease sharply as the doping concentration further increases.After CeO_(2)doping,the oxide content in the magnet increases significantly and the Ce element is uniformly distributed in the magnet.Observing the magnetic domains reveals that doping with CeO_(2)can refine the magnetic domains and make the magnetic domain wall more stable,resulting in a significant increase in the coercivity of the magnets.
基金Shenzhen Fundamental Research Program(Grant No.JCYJ20220818100405013)。
文摘We report the successful growth and characterization of Li_9Cr_3(P_2O_7)_3(PO_4)_2single crystal,and investigate its magnetic properties under external magnetic fields via magnetization and heat capacity measurements.Our study reveals that Li_9Cr_3(P_2O_7)_3(PO_4)_2 is an easy-plane kagome ferromagnet with S=3/2,as evidenced by the Curie–Weiss temperature of 6 K which implies a ferromagnetic exchange coupling in the material.Under zero magnetic field,Li_9Cr_3(P_2O_7)_3(PO_4)_2 undergoes a magnetic transition at TC=2.7 K from a paramagnetic state to a ferromagnetically ordered state with the magnetic moment lying in the kagome plane.By applying a c-axis directional magnetic field to rotate the spin alignment from the kagome plane to the c-axis,we observe a reduction in the magnetic transition temperature as the field is increased.We construct a magnetic phase diagram as a function of temperature and magnetic field applied parallel to the c-axis of Li_9Cr_3(P_2O_7)_3(PO_4)_2 and find that the phase boundary is linear over a certain temperature range.Regarding that theoretically,the field-induced phase transition of the spin reorientation in the easy-plane ferromagnet can be viewed as the ferromagnetic magnon Bose–Einstein condensation(BEC),the phase boundary scaling of field-induced(B c)magnetic transition in Li_9Cr_3(P_2O_7)_3(PO_4)_2 can be described as the quasi-2D magnon BEC,which has been observed in other ferromagnetic materials such as K_2CuF_4.
基金Project supported by the Taishan Scholar Program of Shandong Province,China (Grant No.ts20190939)the Independent Cultivation Program of Innovation Team of Jinan City (Grant No.2021GXRC043)+1 种基金the National Natural Science Foundation of China (Grant No.52173283)the Natural Science Foundation of Shandong Province (Grant No.ZR2020QA052)。
文摘Two-dimensional(2D)nanomaterials with bipolar magnetism show great promise in spintronic applications.Manipulating carriers'spin-polarized orientation in bipolar magnetic semiconductor(BMS)requires a gate voltage,but that is volatile.Recently,a new method has been proposed to solve the problem of volatility by introducing a ferroelectric gate with proper band alignment.In this paper,we predict that the PdX_(2)(X=F,Cl,Br,I)monolayers are 2D ferromagnetic BMS with dynamic stability,thermal stability,and mechanical stability by first-principles calculations.The critical temperatures are higher than the boiling point of liquid nitrogen and the BMS characteristics are robust against external strains and electric fields for PdCl_(2) and PdBr_(2).Then,we manipulate the spin-polarization of PdCl_(2) and PdBr_(2) by introducing a ferroelectric gate to enable magnetic half-metal/semiconductor switching and spin-up/down polarization switching control.Two kinds of spin devices(multiferroic memory and spin filter)have been proposed to realize the spin-polarized directions of electrons.These results demonstrate that PdCl_(2) and PdBr_(2) with BMS characters can be widely used as a general material structure for spintronic devices.
