TiO_(2)is a well-known photocatalyst with a band gap of 3.2 eV,yet its ability to absorb light is limited to the short wavelengths of ultraviolet light.To achieve a more effective photocatalytic material,we have desig...TiO_(2)is a well-known photocatalyst with a band gap of 3.2 eV,yet its ability to absorb light is limited to the short wavelengths of ultraviolet light.To achieve a more effective photocatalytic material,we have designed two-dimensional semiconductor TiOS materials using swarm intelligence algorithms combined with first-principles calculations.Three stable low-energy structures with space groups of P2_(1)/m,P3m1 and P2_(1)/c are identified.Among these structures,the Janus P3m1 phase is a direct bandgap semiconductor,while the P2_(1)/m and P2_(1)/c phases are indirect bandgap semiconductors.Utilizing the accurate hybrid density functional HSE06 method,the band gaps of the three structures are calculated to be 2.34 eV(P2_(1)/m),2.24 eV(P3m1)and 3.22 eV(P2_(1)/c).Optical calculations reveal that TiOS materials exhibit a good light-harvesting capability in both visible and ultraviolet spectral ranges.Moreover,the photocatalytic calculations also indicate that both P2_(1)/m and P3m1 TiOS can provide a strong driving force for converting H_(2)O to H_(2)and O_(2)in an acidic environment with pH=0.The structural stabilities,mechanical properties,electronic structures and hydrogen evolution reaction activities are also discussed in detail.Our research suggests that two-dimensional TiOS materials have potential applications in both semiconductor devices and photocatalysis.展开更多
The structural,relative stability,and electronic properties of two-dimensional AsP_(2)X_(6)(X=S,Se)were predicted and studied using the particle-swarm optimization method and first principles calculations.We proposed ...The structural,relative stability,and electronic properties of two-dimensional AsP_(2)X_(6)(X=S,Se)were predicted and studied using the particle-swarm optimization method and first principles calculations.We proposed two low energy structures with P312 and P-31m phases,both of which the structures are hexagonal in shape and show non-centrosymmetry for the P312 phase and centrosymmetry for the P-31m phase.According to our results,two structural phases are found to be stable thermally and dynamically.The P312 phase of AsP_(2)X_(6)(X=S,Se)are indirect semiconductors with band gaps of 2.44 eV(AsP2S6)and 2.18 eV(AsP2Se6)at the HSE06 level,and their absorption coefficients are predicted to reach the order of 10^(5)cm^(-1)from visible light to ultraviolet region,but the main absorption is manly in the ultraviolet region.The P-31m phase of AsP_(2)X_(6)(X=S,Se)exhibits metal character with the Fermi surface mainly occupied by the p orbital of S/Se.Remarkably,estimated by first principles calculations,the P-31m AsP2S6 is found to be an intrinsic phonon-mediated superconductor with a relatively high critical superconducting temperature of about 13.4 K,and the P-31m AsP2Se6 only has a superconducting temperature of 1.4 K,which suggest that the P-31m AsP2S6 may be a good candidate for a nanoscale superconductor.展开更多
Objective The relationship between fish consumption and stroke is inconsistent,and it is uncertain whether this association varies across predicted stroke risks.Methods A cohort study comprising 95,800 participants fr...Objective The relationship between fish consumption and stroke is inconsistent,and it is uncertain whether this association varies across predicted stroke risks.Methods A cohort study comprising 95,800 participants from the Prediction for Atherosclerotic Cardiovascular Disease Risk in China project was conducted.A standardized questionnaire was used to collect data on fish consumption.Participants were stratified into low-and moderate-to-high-risk categories based on their 10-year stroke risk prediction scores.Hazard ratios(HRs)and 95%confidence intervals(CIs)were estimated using Cox proportional hazard models and additive interaction by relative excess risk due to interaction(RERI),attributable proportion(AP),and synergy index(SI).Results During 703,869 person-years of follow-up,2,773 incident stroke events were identified.Higher fish consumption was associated with a lower risk of stroke,particularly among moderate-to-high-risk individuals(HR=0.53,95%CI:0.47-0.60)than among low-risk individuals(HR=0.64,95%CI:0.49-0.85).A significant additive interaction between fish consumption and predicted stroke risk was observed(RERI=4.08,95%CI:2.80-5.36;SI=1.64,95%CI:1.42-1.89;AP=0.36,95%CI:0.28-0.43).Conclusion Higher fish consumption was associated with a lower risk of stroke,and this beneficial association was more pronounced in individuals with moderate-to-high stroke risk.展开更多
Here,we introduce a partitioned design method that is oriented toward airgap harmonic for permanent magnet vernier(PMV)motors.The method proposes the utilization of airgap flux harmonics as an effective bridge between...Here,we introduce a partitioned design method that is oriented toward airgap harmonic for permanent magnet vernier(PMV)motors.The method proposes the utilization of airgap flux harmonics as an effective bridge between the torque design region and the torque performances.To illustrate the efficacy of this method,a partitioned design PMV motor is presented and compared with the initial design.Firstly,the torque design region of the rotor is artfully divided into the torque enhancement region and ripple reduction region.Meanwhile,the main harmonics that generate output torque are chosen and enhanced,optimization.Moreover,the harmonics that generate torque ripple are selected and reduced based on torque harmonics optimization.Finally,the functions of the partitioned PMV motor torque are assessed based on the finite element method.By the purposeful design of these two regions,the output torque is strengthened while torque ripple is inhibited effectively,verifying the effectiveness and reasonability of the proposed design method.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52272219 and U1904612)the Natural Science Foundation of Henan Province(Grant No.242300421191).
文摘TiO_(2)is a well-known photocatalyst with a band gap of 3.2 eV,yet its ability to absorb light is limited to the short wavelengths of ultraviolet light.To achieve a more effective photocatalytic material,we have designed two-dimensional semiconductor TiOS materials using swarm intelligence algorithms combined with first-principles calculations.Three stable low-energy structures with space groups of P2_(1)/m,P3m1 and P2_(1)/c are identified.Among these structures,the Janus P3m1 phase is a direct bandgap semiconductor,while the P2_(1)/m and P2_(1)/c phases are indirect bandgap semiconductors.Utilizing the accurate hybrid density functional HSE06 method,the band gaps of the three structures are calculated to be 2.34 eV(P2_(1)/m),2.24 eV(P3m1)and 3.22 eV(P2_(1)/c).Optical calculations reveal that TiOS materials exhibit a good light-harvesting capability in both visible and ultraviolet spectral ranges.Moreover,the photocatalytic calculations also indicate that both P2_(1)/m and P3m1 TiOS can provide a strong driving force for converting H_(2)O to H_(2)and O_(2)in an acidic environment with pH=0.The structural stabilities,mechanical properties,electronic structures and hydrogen evolution reaction activities are also discussed in detail.Our research suggests that two-dimensional TiOS materials have potential applications in both semiconductor devices and photocatalysis.
基金Funded by the National Natural Science Foundation of China(No.U1904612)the Natural Science Foundation of Henan Province(No.222300420506)。
文摘The structural,relative stability,and electronic properties of two-dimensional AsP_(2)X_(6)(X=S,Se)were predicted and studied using the particle-swarm optimization method and first principles calculations.We proposed two low energy structures with P312 and P-31m phases,both of which the structures are hexagonal in shape and show non-centrosymmetry for the P312 phase and centrosymmetry for the P-31m phase.According to our results,two structural phases are found to be stable thermally and dynamically.The P312 phase of AsP_(2)X_(6)(X=S,Se)are indirect semiconductors with band gaps of 2.44 eV(AsP2S6)and 2.18 eV(AsP2Se6)at the HSE06 level,and their absorption coefficients are predicted to reach the order of 10^(5)cm^(-1)from visible light to ultraviolet region,but the main absorption is manly in the ultraviolet region.The P-31m phase of AsP_(2)X_(6)(X=S,Se)exhibits metal character with the Fermi surface mainly occupied by the p orbital of S/Se.Remarkably,estimated by first principles calculations,the P-31m AsP2S6 is found to be an intrinsic phonon-mediated superconductor with a relatively high critical superconducting temperature of about 13.4 K,and the P-31m AsP2Se6 only has a superconducting temperature of 1.4 K,which suggest that the P-31m AsP2S6 may be a good candidate for a nanoscale superconductor.
基金supported by the Chinese Academy of Medical Sciences(CAMS)Innovation Fund for Medical Sciences(2021-I2M-1-010,2019-I2M-2-003,and 2017-I2M-1-004)the National High Level Hospital Clinical Research Funding(2022-GSPGG-1,2022-GSP-GG-2)+2 种基金the Research Unit of Prospective Cohort of Cardiovascular Diseases and Cancers,CAMS(2019RU038)the National Key Research and Development Program of China(2018YFE0115300 and 2017YFC0211700)the National Natural Science Foundation of China(82030102,12126602).
文摘Objective The relationship between fish consumption and stroke is inconsistent,and it is uncertain whether this association varies across predicted stroke risks.Methods A cohort study comprising 95,800 participants from the Prediction for Atherosclerotic Cardiovascular Disease Risk in China project was conducted.A standardized questionnaire was used to collect data on fish consumption.Participants were stratified into low-and moderate-to-high-risk categories based on their 10-year stroke risk prediction scores.Hazard ratios(HRs)and 95%confidence intervals(CIs)were estimated using Cox proportional hazard models and additive interaction by relative excess risk due to interaction(RERI),attributable proportion(AP),and synergy index(SI).Results During 703,869 person-years of follow-up,2,773 incident stroke events were identified.Higher fish consumption was associated with a lower risk of stroke,particularly among moderate-to-high-risk individuals(HR=0.53,95%CI:0.47-0.60)than among low-risk individuals(HR=0.64,95%CI:0.49-0.85).A significant additive interaction between fish consumption and predicted stroke risk was observed(RERI=4.08,95%CI:2.80-5.36;SI=1.64,95%CI:1.42-1.89;AP=0.36,95%CI:0.28-0.43).Conclusion Higher fish consumption was associated with a lower risk of stroke,and this beneficial association was more pronounced in individuals with moderate-to-high stroke risk.
基金supported in part by the Natural Science Foundation of China under Grant 51991385,Grant 52177046。
文摘Here,we introduce a partitioned design method that is oriented toward airgap harmonic for permanent magnet vernier(PMV)motors.The method proposes the utilization of airgap flux harmonics as an effective bridge between the torque design region and the torque performances.To illustrate the efficacy of this method,a partitioned design PMV motor is presented and compared with the initial design.Firstly,the torque design region of the rotor is artfully divided into the torque enhancement region and ripple reduction region.Meanwhile,the main harmonics that generate output torque are chosen and enhanced,optimization.Moreover,the harmonics that generate torque ripple are selected and reduced based on torque harmonics optimization.Finally,the functions of the partitioned PMV motor torque are assessed based on the finite element method.By the purposeful design of these two regions,the output torque is strengthened while torque ripple is inhibited effectively,verifying the effectiveness and reasonability of the proposed design method.
