This study investigates the distinct impacts of eastern Pacific(EP)and central Pacific(CP)El Niño events on winter shortwave solar radiation(SSR)in southern China,revealing different spatial distributions and und...This study investigates the distinct impacts of eastern Pacific(EP)and central Pacific(CP)El Niño events on winter shortwave solar radiation(SSR)in southern China,revealing different spatial distributions and underlying mechanisms.The results show that,during the developing winter of EP El Niño,significant SSR reductions occur in southwestern China and the east coast of southern China due to a strong,zonally extended Northwest Pacific anticyclone that transports moisture from the tropical Northwest Pacific and North Indian Ocean,while the northeast of southern China experiences a weak increase in SSR.In contrast,during the developing winter of CP El Niño,SSR decreases in the east of southern China with a significant decrease in the lower basin of the Yangtze River but an increase in the west of southern China with a remarkable increase in eastern Yunnan.The pronounced east-west dipole pattern in SSR anomalies is driven by a meridionally elongated Northwest Pacific anticyclone,which enhances northward moisture transport to the east of southern China while leaving western areas drier.Further research reveals that distinct moisture anomalies during the developing winter of EP and CP events result in divergent SSR distributions across southern China,primarily through modulating the total cloud cover.These findings highlight the critical need to differentiate between El Niño types when predicting medium and long-term variability of radiation in southern China.展开更多
Intelligent reflecting surface(IRS)is widely recognized as a promising technique to enhance the system perfor-mance,and thus is a hot research topic in future wireless communications.In this context,this paper propose...Intelligent reflecting surface(IRS)is widely recognized as a promising technique to enhance the system perfor-mance,and thus is a hot research topic in future wireless communications.In this context,this paper proposes a robust BF scheme to improve the spectrum and energy harvesting efficiencies for the IRS-aided simultaneous wireless information and power transfer(SWIPT)in a cognitive radio network(CRN).Here,the base station(BS)utilizes spectrum assigned to the primary users(PUs)to simultaneously serve multiple energy receivers(ERs)and information receivers(IRs)through IRS-aided multicast technology.In particular,by assuming that only the imperfect channel state information(CSI)is available,we first formulate a constrained problem to maximize the minimal achievable rate of IRs,while satisfying the harvesting energy threshold of ERs,the quality-of-service requirement of IRs,the interference threshold of PUs and transmit power budget of BS.To address the non-convex problem,we then adopt triangle inequality to deal with the channel uncertainty,and propose a low-complexity algorithm combining alternating direction method of multipliers(ADMM)with alternating optimi-zation(AO)to jointly optimize the active and passive beamformers for the BS and IRS,respectively.Finally,our simulation results confirm the effectiveness of the proposed BF scheme and also provide useful insights into the importance of introducing IRS into the CRN with SWIPT.展开更多
Developments of new sheet metal forming technology and theory in China are reviewed in detail in this paper.Advances of crystal plasticity on the deformation mechanism of Mg alloy are firstly described, especially its...Developments of new sheet metal forming technology and theory in China are reviewed in detail in this paper.Advances of crystal plasticity on the deformation mechanism of Mg alloy are firstly described, especially its applications on the prediction of sheet forming process. Then, a new macroscopic constitutive model is introduced, which possesses an enhanced description capacity of tension/compression anisotropy and anisotropic hardening. In order to take into account the twinning process of hexagonal close-packed material, a modified hierarchical multi-scale model is also established with adequate accuracy in a shorter computational time. The advanced forming limit of sheet metal, mainly about aluminum alloy, is also investigated. Besides the above theory developments, some new sheet metal forming technologies are reviewed simultaneously. The warm forming technology of Mg alloy is discussed. New processes to form sheet parts and to bend tubes are proposed by using hard granules. On the other hand, a new kind of ultra-high-strength steel based on typical22 Mn B5 by introducing more residual austenite and Cu-rich phase to increase the elongation and strength and its novel forming method that integrates hot stamping and quenching participation are proposed. Progresses in sheet hydroforming,press forging and electromagnetic forming of sheet metal parts are also summarized.展开更多
The technology of solid-state lighting has developed for decades in various industries.Phosphor,as an element part,determines the application domain of lighting products.For instance,blue and redemitting phosphors are...The technology of solid-state lighting has developed for decades in various industries.Phosphor,as an element part,determines the application domain of lighting products.For instance,blue and redemitting phosphors are required in the process of plant supplementing light,arrow-band emitting phosphors are applied to backlight displays,etc.In this work,a Bi^(3+)-activated blue phosphor was obtained in a symmetrical and co mpact crystal structure of Gd3Sb07(GSO).Then,the co-doping strategy of alkali metal ions(Li^(+),Na^(+),and K^(+))was used to optimize the performance.The result shows that the photoluminescence intensity is increased by 2.1 times and 1.3 times respectively by introducing Li~+and K^(+)ions.Not only that,it also achieves narrow-band emitting with the full width of half-maximum(FWHM)reaching 42 nm through Na^(+)doping,and its excitation peak position also shifts from 322 to 375 nm,which can be well excited by near-ultraviolet(NUV)light emitting diode(LED)chips(365 nm).Meanwhile,the electroluminescence spectrum of GSO:0.6 mol%Bi^(3+),3 wt%Na^(+)matches up to 93.39%of the blue part of the absorption spectrum of chlorophyll a.In summary,the Bi^(3+)-activated blue phosphor reported in this work can synchronously meet the requirements of plant light replenishment and field emission displays.展开更多
With the anticipated growth in air traffic complexity in the coming years,future civil aviation transportation system(CATS)is transforming into a complex cyber–physical–social system,surpassing all previous experien...With the anticipated growth in air traffic complexity in the coming years,future civil aviation transportation system(CATS)is transforming into a complex cyber–physical–social system,surpassing all previous experiences in the history of civil aviation safety management.Therefore,a new safety concept based on a system-of-systems(SoS)perspective is proposed for the next-generation aviation.This article begins by elucidating the complexity of existing aviation risks and emphasizing the necessity for an updated safety concept.It then presents the challenges of current safety management and potential solutions from the new SoS perspective.To address future risks,the concept of SoS safety is introduced with the inspiration of the human immune system in terms of capability,logic,and architecture,which can serve as a guiding framework and methodology for safety engineering in complex large-scale CATS.This concept indicates the transition from“process and outcome-oriented”to“capability-oriented”intelligent safety management.Our research highlights the development directions and potential technological areas that need to be addressed at different stages of SoS safety.The integration of SoS design and operation through rapid iterations enabled by artificial intelligence(AI)will ultimately achieve endogenous SoS safety.展开更多
BACKGROUND Lymph node status is a critical prognostic factor in gastric cancer(GC),but stage migration may occur in pathological lymph nodes(pN)staging.To address this,alternative staging systems such as the positive ...BACKGROUND Lymph node status is a critical prognostic factor in gastric cancer(GC),but stage migration may occur in pathological lymph nodes(pN)staging.To address this,alternative staging systems such as the positive lymph node ratio(LNR)and log odds of positive lymph nodes(LODDS)were introduced.AIM To assess the prognostic accuracy and stratification efficacy of three nodal staging systems in GC.METHODS A systematic review identified 12 studies,from which hazard ratios(HRs)for overall survival(OS)were summarized.Sensitivity analyses,subgroup analyses,publication bias assessments,and quality evaluations were conducted.To enhance comparability,data from studies with identical cutoff values for pN,LNR,and LODDS were pooled.Homogeneous stratification was then applied to generate Kaplan-Meier(KM)survival curves,assessing the stratification efficacy of three staging systems.RESULTS The HRs and 95%confidence intervals for pN,LNR,and LODDS were 2.16(1.72-2.73),2.05(1.65-2.55),and 3.15(2.15-4.37),respectively,confirming all three as independent prognostic risk factors for OS.Comparative analysis of HRs demonstrated that LODDS had superior prognostic predictive power over LNR and pN.KM curves for pN(N0,N1,N2,N3a,N3b),LNR(0.1/0.2/0.5),and LODDS(-1.5/-1.0/-0.5/0)revealed significant differences(P<0.001)among all prognostic stratifications.Mean differences and standard deviations in 60-month relative survival were 27.93%±0.29%,41.70%±0.30%,and 26.60%±0.28%for pN,LNR,and LODDS,respectively.CONCLUSION All three staging systems are independent prognostic factors for OS.LODDS demonstrated the highest specificity,making it especially useful for predicting outcomes,while pN was the most effective in homogeneous stratification,offering better patient differentiation.These findings highlight the complementary roles of LODDS and pN in enhancing prognostic accuracy and stratification.展开更多
The dual three-phase PMSM(DTP-PMSM)drives have received wide attention at high-power high-efficiency applications due to their merits of high output current ability and copper-loss-free field excitation.Meanwhile,the ...The dual three-phase PMSM(DTP-PMSM)drives have received wide attention at high-power high-efficiency applications due to their merits of high output current ability and copper-loss-free field excitation.Meanwhile,the DTPPMSM drive provides higher fault-tolerant capability for highreliability applications,e.g.,pumps and actuators in aircraft.For high-power drives with limited switching frequencies and highspeed drives with large fundamental frequencies,the ratio of switching frequency to fundamental frequency,i.e.,the carrier ratio,is usually below 15,which would significantly degrade the control performance.The purpose of this paper is to review the recent work on the modulation and control schemes for improving the operation performance of DTP-PMSM drives with low carrier ratios.Specifically,three categories of methods,i.e.,the space vector modulation based control,the model predictive control(MPC),and the optimized pulse pattern(OPP)based control are reviewed with principles and performance.In addition,brief discussions regarding the comparison and future trends are presented for low-carrier-ratio(LCR)modulation and control schemes of DTP-PMSM drives.展开更多
Heterocyclic compounds play an important role in organic hole transport materials(HTMs)for perovskite solar cells(PSCs).Herein,a series of linear D-π-D HTMs(O-CBz,S-CBz,SO_(2)-CBz)with different dibenzoheterocycles c...Heterocyclic compounds play an important role in organic hole transport materials(HTMs)for perovskite solar cells(PSCs).Herein,a series of linear D-π-D HTMs(O-CBz,S-CBz,SO_(2)-CBz)with different dibenzoheterocycles core(dibenzofuran,dibenzothiophene,dibenzothiophene sulfone)were designed and synthesized,and their applications in PSCs were investigated.The intrinsic properties(CV,UV-vis,hole mobility and conductivity)were systematically investigated,demonstrating that all three materials are suitable HTMs for planar n-i-p type PSCs.Benefiting from the excellent hole mobility and conductivity,good film forming ability,and outstanding charge extraction and transport capability of S-CBz,FAPbI_(3)-based PSCs using S-CBz as HTM achieved a PCE of 25.0%,which is superior to that of Spiro-OMeTAD-based PSCs fabricated under the same conditions(23.9%).Furthermore,due to the interaction between S and Pb^(2+),SCBz-based PSC devices exhibited improved stability.This work demonstrates that dibenzothiophene-based architectures are promising candidates for high-performance HTMs in perovskite solar cell architectures.展开更多
Organic molecule passivation of perovskite surfaces has emerged as a promising strategy for efficient and durable perovskite solar cells(PSCs).While many materials have been reported,the optimization of molecular stru...Organic molecule passivation of perovskite surfaces has emerged as a promising strategy for efficient and durable perovskite solar cells(PSCs).While many materials have been reported,the optimization of molecular structure for the best passivation effect remains of significant interest but lacks sufficient study.In this work,we designed and synthesized three novel donor–acceptor-donor(D-A-D)type conjugated organic small molecules with varying alkyl chain lengths to regulate the interface between perovskite and Spiro-OMeTAD.Among them,the OSIT molecule,which features an n-octyl side chain of optimal length,demonstrated a balanced interfacial contact and interaction with the perovskite surface.Beyond the passivation effect of the electron-rich C=O group on undercoordinated Pb2+defects,OSIT optimizes energy level alignment and improves charge extraction by acting as an efficient hole transport channel.As a result,PSCs with OSIT interfacial layer achieved an exceptional efficiency of 25.48%and a high open-circuit voltage of 1.18 V.Furthermore,the durability of unencapsulated devices was significantly enhanced under various environmental conditions,maintaining 93.7%of their initial efficiency after 1000 h of maximum power point tracking in a nitrogen atmosphere.This study provides valuable insights into the rational design of D-A-D type materials for effective interface modification in PSCs.展开更多
BACKGROUND Duodenal stump fistula(DSF)is a rare yet serious complication following gastric cancer surgery.The risk factors associated with DSF,as well as the predictive models,remain insufficiently elucidated.AIM To i...BACKGROUND Duodenal stump fistula(DSF)is a rare yet serious complication following gastric cancer surgery.The risk factors associated with DSF,as well as the predictive models,remain insufficiently elucidated.AIM To identify DSF risk factors following radical gastrectomy with Roux-en-Y anastomosis,develop a predictive model,and evaluate impact on prognosis.METHODS This retrospective cohort study was conducted on patients undergoing radical gastrectomy with Roux-en-Y anastomosis for gastric cancer at Juntendo University from 2015 to 2021(n=325).Univariate and multivariate analyses were performed to identify the risk factors associated with DSF.Based on the independent risk factors,a predictive nomogram was developed and subsequently evaluated using receiver operating characteristic curve analysis.Kaplan-Meier survival curves were utilized to assess the impact of DSF on overall survival(OS),cancerspecific survival(CSS),and disease-free survival(DFS).RESULTS Among the 325 patients analyzed,DSF was observed in 7(2.2%)cases.No DSF was observed in 110 patients where the duodenal stump suturing fixation technique to the jejunal wall was used.Multivariate analysis confirmed that age[odds ratio(OR)=1.17,P=0.015]and obstructive ventilatory failure(OVF)(OR=14.03,P=0.001)were independent risk factors for DSF.The predictive nomogram was constructed based on age and OVF,which exhibited strong performance(area under the curve=0.90,95%confidence interval:0.82-0.99).Kaplan-Meier analysis revealed a statistically significant reduction in CSS for patients with DSF,whereas no significant differences were observed in OS or DFS.CONCLUSION Age and OVF are independent risk factors for DSF,which worsens CSS.A nomogram predicts DSF accurately,and innovative surgical techniques may reduce its occurrence.展开更多
While renewable power generation and vehicle electrification are promising solutions to reduce greenhouse gas emissions, it faces great challenges to effectively integrate them in a power grid. The weather-dependent p...While renewable power generation and vehicle electrification are promising solutions to reduce greenhouse gas emissions, it faces great challenges to effectively integrate them in a power grid. The weather-dependent power generation of renewable energy sources, such as Photovoltaic (PV) arrays, could introduce significant intermittency to a power grid. Meanwhile, uncontrolled PEV charging may cause load surge in a power grid. This paper studies the optimization of PEV charging/discharging scheduling to reduce customer cost and improve grid performance. Optimization algorithms are developed for three cases: 1) minimize cost, 2) minimize power deviation from a pre-defined power profile, and 3) combine objective functions in 1) and 2). A Microgrid with PV arrays, bi-directional PEV charging stations, and a commercial building is used in this study. The bi-directional power from/to PEVs provides the opportunity of using PEVs to reduce the intermittency of PV power generation and the peak load of the Microgrid. Simulation has been performed for all three cases and the simulation results show that the presented optimization algorithms can meet defined objectives.展开更多
基金funded by a Project from China Southern Power Grid Company Ltd.(Nos.ZBKJXM20232481 and ZBKJXM20232482)。
文摘This study investigates the distinct impacts of eastern Pacific(EP)and central Pacific(CP)El Niño events on winter shortwave solar radiation(SSR)in southern China,revealing different spatial distributions and underlying mechanisms.The results show that,during the developing winter of EP El Niño,significant SSR reductions occur in southwestern China and the east coast of southern China due to a strong,zonally extended Northwest Pacific anticyclone that transports moisture from the tropical Northwest Pacific and North Indian Ocean,while the northeast of southern China experiences a weak increase in SSR.In contrast,during the developing winter of CP El Niño,SSR decreases in the east of southern China with a significant decrease in the lower basin of the Yangtze River but an increase in the west of southern China with a remarkable increase in eastern Yunnan.The pronounced east-west dipole pattern in SSR anomalies is driven by a meridionally elongated Northwest Pacific anticyclone,which enhances northward moisture transport to the east of southern China while leaving western areas drier.Further research reveals that distinct moisture anomalies during the developing winter of EP and CP events result in divergent SSR distributions across southern China,primarily through modulating the total cloud cover.These findings highlight the critical need to differentiate between El Niño types when predicting medium and long-term variability of radiation in southern China.
基金supported in part by the Key International Cooper-ation Research Project under Grant 61720106003in part by NUPTSF under Grant NY220111+1 种基金in part by NUPTSF under Grant NY221009in part by the Postgraduate Research and Practice Innovation Program of Jiangsu Province under Grant KYCX22_0959.
文摘Intelligent reflecting surface(IRS)is widely recognized as a promising technique to enhance the system perfor-mance,and thus is a hot research topic in future wireless communications.In this context,this paper proposes a robust BF scheme to improve the spectrum and energy harvesting efficiencies for the IRS-aided simultaneous wireless information and power transfer(SWIPT)in a cognitive radio network(CRN).Here,the base station(BS)utilizes spectrum assigned to the primary users(PUs)to simultaneously serve multiple energy receivers(ERs)and information receivers(IRs)through IRS-aided multicast technology.In particular,by assuming that only the imperfect channel state information(CSI)is available,we first formulate a constrained problem to maximize the minimal achievable rate of IRs,while satisfying the harvesting energy threshold of ERs,the quality-of-service requirement of IRs,the interference threshold of PUs and transmit power budget of BS.To address the non-convex problem,we then adopt triangle inequality to deal with the channel uncertainty,and propose a low-complexity algorithm combining alternating direction method of multipliers(ADMM)with alternating optimi-zation(AO)to jointly optimize the active and passive beamformers for the BS and IRS,respectively.Finally,our simulation results confirm the effectiveness of the proposed BF scheme and also provide useful insights into the importance of introducing IRS into the CRN with SWIPT.
文摘Developments of new sheet metal forming technology and theory in China are reviewed in detail in this paper.Advances of crystal plasticity on the deformation mechanism of Mg alloy are firstly described, especially its applications on the prediction of sheet forming process. Then, a new macroscopic constitutive model is introduced, which possesses an enhanced description capacity of tension/compression anisotropy and anisotropic hardening. In order to take into account the twinning process of hexagonal close-packed material, a modified hierarchical multi-scale model is also established with adequate accuracy in a shorter computational time. The advanced forming limit of sheet metal, mainly about aluminum alloy, is also investigated. Besides the above theory developments, some new sheet metal forming technologies are reviewed simultaneously. The warm forming technology of Mg alloy is discussed. New processes to form sheet parts and to bend tubes are proposed by using hard granules. On the other hand, a new kind of ultra-high-strength steel based on typical22 Mn B5 by introducing more residual austenite and Cu-rich phase to increase the elongation and strength and its novel forming method that integrates hot stamping and quenching participation are proposed. Progresses in sheet hydroforming,press forging and electromagnetic forming of sheet metal parts are also summarized.
基金Project supported by the Key R&D Projects in Hunan Province(2021SK2047,2022NK2044)Science and Technology Innovation Program of Hunan Province(2022WZ1022)Superior Youth Project of the Science Research Project of Hunan Provincial Department of Education(22B0211)。
文摘The technology of solid-state lighting has developed for decades in various industries.Phosphor,as an element part,determines the application domain of lighting products.For instance,blue and redemitting phosphors are required in the process of plant supplementing light,arrow-band emitting phosphors are applied to backlight displays,etc.In this work,a Bi^(3+)-activated blue phosphor was obtained in a symmetrical and co mpact crystal structure of Gd3Sb07(GSO).Then,the co-doping strategy of alkali metal ions(Li^(+),Na^(+),and K^(+))was used to optimize the performance.The result shows that the photoluminescence intensity is increased by 2.1 times and 1.3 times respectively by introducing Li~+and K^(+)ions.Not only that,it also achieves narrow-band emitting with the full width of half-maximum(FWHM)reaching 42 nm through Na^(+)doping,and its excitation peak position also shifts from 322 to 375 nm,which can be well excited by near-ultraviolet(NUV)light emitting diode(LED)chips(365 nm).Meanwhile,the electroluminescence spectrum of GSO:0.6 mol%Bi^(3+),3 wt%Na^(+)matches up to 93.39%of the blue part of the absorption spectrum of chlorophyll a.In summary,the Bi^(3+)-activated blue phosphor reported in this work can synchronously meet the requirements of plant light replenishment and field emission displays.
基金supported by the National Natural Science Foundation of China(72225012)the National Key Research and Development Program of China(2023YFB4302901)+1 种基金the National Natural Science Foundation of China(72288101,71822101,and 62201577)the Safety Capability Building Fund of the Civil Aviation Administration of China(ASSA2023/19).
文摘With the anticipated growth in air traffic complexity in the coming years,future civil aviation transportation system(CATS)is transforming into a complex cyber–physical–social system,surpassing all previous experiences in the history of civil aviation safety management.Therefore,a new safety concept based on a system-of-systems(SoS)perspective is proposed for the next-generation aviation.This article begins by elucidating the complexity of existing aviation risks and emphasizing the necessity for an updated safety concept.It then presents the challenges of current safety management and potential solutions from the new SoS perspective.To address future risks,the concept of SoS safety is introduced with the inspiration of the human immune system in terms of capability,logic,and architecture,which can serve as a guiding framework and methodology for safety engineering in complex large-scale CATS.This concept indicates the transition from“process and outcome-oriented”to“capability-oriented”intelligent safety management.Our research highlights the development directions and potential technological areas that need to be addressed at different stages of SoS safety.The integration of SoS design and operation through rapid iterations enabled by artificial intelligence(AI)will ultimately achieve endogenous SoS safety.
基金the Clinical Medical Team Introduction Program of Suzhou,No.SZYJTD201804.
文摘BACKGROUND Lymph node status is a critical prognostic factor in gastric cancer(GC),but stage migration may occur in pathological lymph nodes(pN)staging.To address this,alternative staging systems such as the positive lymph node ratio(LNR)and log odds of positive lymph nodes(LODDS)were introduced.AIM To assess the prognostic accuracy and stratification efficacy of three nodal staging systems in GC.METHODS A systematic review identified 12 studies,from which hazard ratios(HRs)for overall survival(OS)were summarized.Sensitivity analyses,subgroup analyses,publication bias assessments,and quality evaluations were conducted.To enhance comparability,data from studies with identical cutoff values for pN,LNR,and LODDS were pooled.Homogeneous stratification was then applied to generate Kaplan-Meier(KM)survival curves,assessing the stratification efficacy of three staging systems.RESULTS The HRs and 95%confidence intervals for pN,LNR,and LODDS were 2.16(1.72-2.73),2.05(1.65-2.55),and 3.15(2.15-4.37),respectively,confirming all three as independent prognostic risk factors for OS.Comparative analysis of HRs demonstrated that LODDS had superior prognostic predictive power over LNR and pN.KM curves for pN(N0,N1,N2,N3a,N3b),LNR(0.1/0.2/0.5),and LODDS(-1.5/-1.0/-0.5/0)revealed significant differences(P<0.001)among all prognostic stratifications.Mean differences and standard deviations in 60-month relative survival were 27.93%±0.29%,41.70%±0.30%,and 26.60%±0.28%for pN,LNR,and LODDS,respectively.CONCLUSION All three staging systems are independent prognostic factors for OS.LODDS demonstrated the highest specificity,making it especially useful for predicting outcomes,while pN was the most effective in homogeneous stratification,offering better patient differentiation.These findings highlight the complementary roles of LODDS and pN in enhancing prognostic accuracy and stratification.
基金supported by the National Key Research and Development Program of China under the grant of 2022YFB3403100。
文摘The dual three-phase PMSM(DTP-PMSM)drives have received wide attention at high-power high-efficiency applications due to their merits of high output current ability and copper-loss-free field excitation.Meanwhile,the DTPPMSM drive provides higher fault-tolerant capability for highreliability applications,e.g.,pumps and actuators in aircraft.For high-power drives with limited switching frequencies and highspeed drives with large fundamental frequencies,the ratio of switching frequency to fundamental frequency,i.e.,the carrier ratio,is usually below 15,which would significantly degrade the control performance.The purpose of this paper is to review the recent work on the modulation and control schemes for improving the operation performance of DTP-PMSM drives with low carrier ratios.Specifically,three categories of methods,i.e.,the space vector modulation based control,the model predictive control(MPC),and the optimized pulse pattern(OPP)based control are reviewed with principles and performance.In addition,brief discussions regarding the comparison and future trends are presented for low-carrier-ratio(LCR)modulation and control schemes of DTP-PMSM drives.
基金supported by the financial support from the National Natural Science Foundation of China(Nos.22279046,22179053)Natural Science Excellent Youth Foundation of Jiangsu Province(No.BK20220112)Special Foundation for Carbon Peak Carbon Neutralization Technology Innovation Program of Jiangsu Province(No.BE2022026-2).
文摘Heterocyclic compounds play an important role in organic hole transport materials(HTMs)for perovskite solar cells(PSCs).Herein,a series of linear D-π-D HTMs(O-CBz,S-CBz,SO_(2)-CBz)with different dibenzoheterocycles core(dibenzofuran,dibenzothiophene,dibenzothiophene sulfone)were designed and synthesized,and their applications in PSCs were investigated.The intrinsic properties(CV,UV-vis,hole mobility and conductivity)were systematically investigated,demonstrating that all three materials are suitable HTMs for planar n-i-p type PSCs.Benefiting from the excellent hole mobility and conductivity,good film forming ability,and outstanding charge extraction and transport capability of S-CBz,FAPbI_(3)-based PSCs using S-CBz as HTM achieved a PCE of 25.0%,which is superior to that of Spiro-OMeTAD-based PSCs fabricated under the same conditions(23.9%).Furthermore,due to the interaction between S and Pb^(2+),SCBz-based PSC devices exhibited improved stability.This work demonstrates that dibenzothiophene-based architectures are promising candidates for high-performance HTMs in perovskite solar cell architectures.
基金supported by the National Natural Science Foundation of China(22179053,22279046)Natural Science Excellent Youth Foundation of Jiangsu Provincial(BK20220112)+1 种基金Special Foundation for Carbon Peak Carbon Neutralization Technology Innovation Program of Jiangsu Province(BE2022026-2)JSPS KAKENHI(20K15385,20H02817,and 24H00486)。
文摘Organic molecule passivation of perovskite surfaces has emerged as a promising strategy for efficient and durable perovskite solar cells(PSCs).While many materials have been reported,the optimization of molecular structure for the best passivation effect remains of significant interest but lacks sufficient study.In this work,we designed and synthesized three novel donor–acceptor-donor(D-A-D)type conjugated organic small molecules with varying alkyl chain lengths to regulate the interface between perovskite and Spiro-OMeTAD.Among them,the OSIT molecule,which features an n-octyl side chain of optimal length,demonstrated a balanced interfacial contact and interaction with the perovskite surface.Beyond the passivation effect of the electron-rich C=O group on undercoordinated Pb2+defects,OSIT optimizes energy level alignment and improves charge extraction by acting as an efficient hole transport channel.As a result,PSCs with OSIT interfacial layer achieved an exceptional efficiency of 25.48%and a high open-circuit voltage of 1.18 V.Furthermore,the durability of unencapsulated devices was significantly enhanced under various environmental conditions,maintaining 93.7%of their initial efficiency after 1000 h of maximum power point tracking in a nitrogen atmosphere.This study provides valuable insights into the rational design of D-A-D type materials for effective interface modification in PSCs.
基金Supported by the China Scholarship Council Fund,No.202308050094.
文摘BACKGROUND Duodenal stump fistula(DSF)is a rare yet serious complication following gastric cancer surgery.The risk factors associated with DSF,as well as the predictive models,remain insufficiently elucidated.AIM To identify DSF risk factors following radical gastrectomy with Roux-en-Y anastomosis,develop a predictive model,and evaluate impact on prognosis.METHODS This retrospective cohort study was conducted on patients undergoing radical gastrectomy with Roux-en-Y anastomosis for gastric cancer at Juntendo University from 2015 to 2021(n=325).Univariate and multivariate analyses were performed to identify the risk factors associated with DSF.Based on the independent risk factors,a predictive nomogram was developed and subsequently evaluated using receiver operating characteristic curve analysis.Kaplan-Meier survival curves were utilized to assess the impact of DSF on overall survival(OS),cancerspecific survival(CSS),and disease-free survival(DFS).RESULTS Among the 325 patients analyzed,DSF was observed in 7(2.2%)cases.No DSF was observed in 110 patients where the duodenal stump suturing fixation technique to the jejunal wall was used.Multivariate analysis confirmed that age[odds ratio(OR)=1.17,P=0.015]and obstructive ventilatory failure(OVF)(OR=14.03,P=0.001)were independent risk factors for DSF.The predictive nomogram was constructed based on age and OVF,which exhibited strong performance(area under the curve=0.90,95%confidence interval:0.82-0.99).Kaplan-Meier analysis revealed a statistically significant reduction in CSS for patients with DSF,whereas no significant differences were observed in OS or DFS.CONCLUSION Age and OVF are independent risk factors for DSF,which worsens CSS.A nomogram predicts DSF accurately,and innovative surgical techniques may reduce its occurrence.
文摘While renewable power generation and vehicle electrification are promising solutions to reduce greenhouse gas emissions, it faces great challenges to effectively integrate them in a power grid. The weather-dependent power generation of renewable energy sources, such as Photovoltaic (PV) arrays, could introduce significant intermittency to a power grid. Meanwhile, uncontrolled PEV charging may cause load surge in a power grid. This paper studies the optimization of PEV charging/discharging scheduling to reduce customer cost and improve grid performance. Optimization algorithms are developed for three cases: 1) minimize cost, 2) minimize power deviation from a pre-defined power profile, and 3) combine objective functions in 1) and 2). A Microgrid with PV arrays, bi-directional PEV charging stations, and a commercial building is used in this study. The bi-directional power from/to PEVs provides the opportunity of using PEVs to reduce the intermittency of PV power generation and the peak load of the Microgrid. Simulation has been performed for all three cases and the simulation results show that the presented optimization algorithms can meet defined objectives.
