The integration of the intelligent reflecting surface(IRS)with simultaneous wireless information and power transfer(SWIPT)has emerged as a cost-effective and efficient solution to enhance the performance of informatio...The integration of the intelligent reflecting surface(IRS)with simultaneous wireless information and power transfer(SWIPT)has emerged as a cost-effective and efficient solution to enhance the performance of information and energy transfer.In this research,a hybrid active/passive IRS-assisted SWIPT system is proposed.Specifically,an active IRS(AIRS)and a passive IRS(PIRS)are deployed in the SWIPT system to facilitate a multiantenna base station(BS)in simultaneously delivering information and energy to multiple information users(IUs)and energy users(EUs).The objective is to maximize the sum throughput by jointly optimizing the transmitter beamforming and the reflection coefficient matrices of the AIRS and the PIRS while satisfying the transmitter power constraints,the energy harvesting(EH)requirements of EUs,and the AIRS amplification power limitations.However,the optimization variables are highly coupled and cannot be solved directly.To tackle this complex problem,we propose an efficient algorithm based on alternating optimization(AO)and semi-definite relaxation(SDR)techniques to obtain high-quality solutions.Simulation results demonstrate that the hybrid active/passive IRSassisted SWIPT system significantly enhances throughput performance and outperforms benchmark systems.展开更多
A series of blue and blue‑green Ir(Ⅲ)complexes has been investigated theoretically to explore their electronic structures,photophysical properties,efficiency roll‑off effect,and thermal activation delayed fluorescenc...A series of blue and blue‑green Ir(Ⅲ)complexes has been investigated theoretically to explore their electronic structures,photophysical properties,efficiency roll‑off effect,and thermal activation delayed fluorescence(TADF)properties.All calculations were performed using density functional theory(DFT)and time‑dependent density functional theory(TDDFT).Calculations for electronic structures,frontier molecular orbital characteristics(which determine the efficiency roll‑off effect of the complexes),and photophysical properties were conducted using the Gaussian 09 software package.The calculation of spin‑orbit coupling matrix elements<T|HSOC|S>,which determine the TADF properties of the complexes,was performed using the ORCA software package.The calculation results show that the auxiliary ligand tetraphenylimidodiphosphinate(tpip),a strong electron‑withdrawing group,can mitigate the efficiency roll‑off effect of the complex.Furthermore,TADF is observed in one of the designed complexes,(F_(3)Phppy)_(2)Ir(tpip),where F_(3)Phppy=2‑[4‑(2,4,6‑trifluorophenyl)phenyl]pyridine.展开更多
Heteroatom doping is a promising strategy for designing cost-effective and stable electrocatalysts toward the oxygen evolution reaction(OER),but the enhancement mechanism remains unclear.Herein,atomic Ir-O-Cu and Ir-O...Heteroatom doping is a promising strategy for designing cost-effective and stable electrocatalysts toward the oxygen evolution reaction(OER),but the enhancement mechanism remains unclear.Herein,atomic Ir-O-Cu and Ir-O-Ir motifs are engineered into CuO nanowires via cation exchange and dehydration to elucidate the OER mechanism.Systematic characterizations confirm the atomic dispersion of Ir within the CuO lattice and the electron transfer from Ir to CuO while preserving the host structure.The asprepared single-atom Ir-doped CuO(IrSA-CuO),featuring predominant Cu-O-Ir motifs and coexisting IrO-Ir motifs,achieves a low OER overpotential of 204 mV at 10 mA cm^(-2)in 1 M KOH,coupled with a 69-fold higher mass activity than commercial IrO_(2).Furthermore,the Ir_(SA)-CuO maintains long-term stability for 300 h at 200 mA cm^(-2)with minimal overpotential alteration and an additional 120 h at500 mA cm^(-2)with overpotential increased by 15 mV.In situ Raman spectroscopy reveals that the Ir-O-Ir motifs suppress Cu^(Ⅱ) oxidation to Cu^(Ⅲ) by delaying the onset potential,enhancing the structural stability during OER.Density functional theory calculations demonstrate the Cu-O-Ir motifs lower the adsorption energy of bridged ^(*)O via asymmetric bonding,accelerating ^(*)OOH formation in the ratedetermining step.This work presents a heteroatom engineering strategy to balance electrocatalytic activity and durability,providing a blueprint for industrial electrocatalyst design.展开更多
高剂量率(High Dose Rate,HDR)近距离放射治疗在现代临床近距离放疗中得到广泛应用,临床实践依赖于^(192)Ir源的精确剂量学参数。由于不同放射源设计各异,各型号放射源需特定的剂量学参数。尽管国际上已针对^(192)Ir源进行了广泛研究,...高剂量率(High Dose Rate,HDR)近距离放射治疗在现代临床近距离放疗中得到广泛应用,临床实践依赖于^(192)Ir源的精确剂量学参数。由于不同放射源设计各异,各型号放射源需特定的剂量学参数。尽管国际上已针对^(192)Ir源进行了广泛研究,但针对原子高科股份有限公司生产的HDR ^(192)Ir源的国内研究较少。为了计算国产HDR ^(192)Ir源的剂量学参数,依据美国医学物理师协会(American Association of Physicists in Medicine,AAPM)TG43-U1推荐的剂量学参数计算方法,使用蒙特卡罗模拟软件建立^(192)Ir源的详细结构模型进行模拟计算。模拟结果显示:剂量率常数为1.105 cGy·h^(-1)·U^(-1),与文献值差异小于1.2%;单位活度空气比释动能率为9.788×10^(-8) U·Bq^(-1),差异为0.23%;径向剂量函数和各向异性函数结果与文献一致。结果表明,该模型对于国产HDR ^(192)Ir源的临床应用,具有一定的指导意义。展开更多
基金National Natural Science Foundation of China(No.62301141)。
文摘The integration of the intelligent reflecting surface(IRS)with simultaneous wireless information and power transfer(SWIPT)has emerged as a cost-effective and efficient solution to enhance the performance of information and energy transfer.In this research,a hybrid active/passive IRS-assisted SWIPT system is proposed.Specifically,an active IRS(AIRS)and a passive IRS(PIRS)are deployed in the SWIPT system to facilitate a multiantenna base station(BS)in simultaneously delivering information and energy to multiple information users(IUs)and energy users(EUs).The objective is to maximize the sum throughput by jointly optimizing the transmitter beamforming and the reflection coefficient matrices of the AIRS and the PIRS while satisfying the transmitter power constraints,the energy harvesting(EH)requirements of EUs,and the AIRS amplification power limitations.However,the optimization variables are highly coupled and cannot be solved directly.To tackle this complex problem,we propose an efficient algorithm based on alternating optimization(AO)and semi-definite relaxation(SDR)techniques to obtain high-quality solutions.Simulation results demonstrate that the hybrid active/passive IRSassisted SWIPT system significantly enhances throughput performance and outperforms benchmark systems.
文摘A series of blue and blue‑green Ir(Ⅲ)complexes has been investigated theoretically to explore their electronic structures,photophysical properties,efficiency roll‑off effect,and thermal activation delayed fluorescence(TADF)properties.All calculations were performed using density functional theory(DFT)and time‑dependent density functional theory(TDDFT).Calculations for electronic structures,frontier molecular orbital characteristics(which determine the efficiency roll‑off effect of the complexes),and photophysical properties were conducted using the Gaussian 09 software package.The calculation of spin‑orbit coupling matrix elements<T|HSOC|S>,which determine the TADF properties of the complexes,was performed using the ORCA software package.The calculation results show that the auxiliary ligand tetraphenylimidodiphosphinate(tpip),a strong electron‑withdrawing group,can mitigate the efficiency roll‑off effect of the complex.Furthermore,TADF is observed in one of the designed complexes,(F_(3)Phppy)_(2)Ir(tpip),where F_(3)Phppy=2‑[4‑(2,4,6‑trifluorophenyl)phenyl]pyridine.
基金supported by the Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZR124)。
文摘Heteroatom doping is a promising strategy for designing cost-effective and stable electrocatalysts toward the oxygen evolution reaction(OER),but the enhancement mechanism remains unclear.Herein,atomic Ir-O-Cu and Ir-O-Ir motifs are engineered into CuO nanowires via cation exchange and dehydration to elucidate the OER mechanism.Systematic characterizations confirm the atomic dispersion of Ir within the CuO lattice and the electron transfer from Ir to CuO while preserving the host structure.The asprepared single-atom Ir-doped CuO(IrSA-CuO),featuring predominant Cu-O-Ir motifs and coexisting IrO-Ir motifs,achieves a low OER overpotential of 204 mV at 10 mA cm^(-2)in 1 M KOH,coupled with a 69-fold higher mass activity than commercial IrO_(2).Furthermore,the Ir_(SA)-CuO maintains long-term stability for 300 h at 200 mA cm^(-2)with minimal overpotential alteration and an additional 120 h at500 mA cm^(-2)with overpotential increased by 15 mV.In situ Raman spectroscopy reveals that the Ir-O-Ir motifs suppress Cu^(Ⅱ) oxidation to Cu^(Ⅲ) by delaying the onset potential,enhancing the structural stability during OER.Density functional theory calculations demonstrate the Cu-O-Ir motifs lower the adsorption energy of bridged ^(*)O via asymmetric bonding,accelerating ^(*)OOH formation in the ratedetermining step.This work presents a heteroatom engineering strategy to balance electrocatalytic activity and durability,providing a blueprint for industrial electrocatalyst design.
文摘高剂量率(High Dose Rate,HDR)近距离放射治疗在现代临床近距离放疗中得到广泛应用,临床实践依赖于^(192)Ir源的精确剂量学参数。由于不同放射源设计各异,各型号放射源需特定的剂量学参数。尽管国际上已针对^(192)Ir源进行了广泛研究,但针对原子高科股份有限公司生产的HDR ^(192)Ir源的国内研究较少。为了计算国产HDR ^(192)Ir源的剂量学参数,依据美国医学物理师协会(American Association of Physicists in Medicine,AAPM)TG43-U1推荐的剂量学参数计算方法,使用蒙特卡罗模拟软件建立^(192)Ir源的详细结构模型进行模拟计算。模拟结果显示:剂量率常数为1.105 cGy·h^(-1)·U^(-1),与文献值差异小于1.2%;单位活度空气比释动能率为9.788×10^(-8) U·Bq^(-1),差异为0.23%;径向剂量函数和各向异性函数结果与文献一致。结果表明,该模型对于国产HDR ^(192)Ir源的临床应用,具有一定的指导意义。
