As an emerging member of the two-dimensional(2D)material family,V_(2)CT_(X)MXene shows great potential in the application of lithium-ion capacitors(LICs)due to its unique structure and excellent electrical conductivit...As an emerging member of the two-dimensional(2D)material family,V_(2)CT_(X)MXene shows great potential in the application of lithium-ion capacitors(LICs)due to its unique structure and excellent electrical conductivity.However,severe nanosheets stacking and intra-layer transport barriers have limited the further development of V_(2)CT_(X)MXene-based materials.Herein,we prepared Kions and–O functional group co-modified V_(2)CT_(X)MXene(VCT-K)and further incorporated it with single-walled carbon nanotube(SWCNT),obtaining freestanding V_(2)CT_(X)composite films(VCT-K@C)with the 3D conductive network.Significantly,K+ions were introduced into V_(2)CT_(X)MXene to stabilize the interlayer structure and prevent the aggregation of nanosheets,the terminal group of–O was controllably modified on the surface of MXene to improve the Li+ions storage reversible capacities and the SWCNT acted as the bridge between MXene nanosheets to opens up the channels for ion/electron transportation in the longitudinal direction.Benefited from the synergistic effect of VCT-K and SWCNT,the VCT-K@C exhibits superior reversible specific capacities of 671.8 mA h g^(-1)at 0.1 A g^(-1)and 318 mA h g^(-1)at 1.0 A g^(-1).Furthermore,the assembled LICs with VCT-K@C anode coupling activated carbon(AC)cathode deliver an outstanding power density of 19.0 kW kg^(-1)at 67.4 Wh kg^(-1),a high energy density of 140.5 Wh kg^(-1)at 94.8 W kg^(-1)and a stable capacitance retention of 86%after 6000 cycles at 10 A g^(-1).Such unique structures and excellent electrochemical properties are expected to pave the way for the large-scale application in LICs of MXene-based materials.展开更多
Twist,the very degree of freedom in van der Waals heterostructures,offers a compelling avenue to manipulate and tailor their electrical and optical characteristics.In particular,moirépatterns in twisted homobilay...Twist,the very degree of freedom in van der Waals heterostructures,offers a compelling avenue to manipulate and tailor their electrical and optical characteristics.In particular,moirépatterns in twisted homobilayer transition metal dichalcogenides(TMDs)lead to zone folding and miniband formation in the resulting electronic bands,holding the promise to exhibit inter-layer excitonic optical phenomena.Although some experiments have shown the existence of twist-angle-dependent intra-and inter-layer excitons in twisted MoSe2 homobilayers,electrical control of the interlayer excitons in MoSe_(2) is relatively under-explored.Here,we show the signatures of the moiréeffect on intralayer and interlayer excitons in 2H-stacked twisted MoSe2 homobilayers.Doping-and electric field-dependent photoluminescence mea-surements at low temperatures give evidence of the momentum-direct K-K intralayer excitons,and the momentum-indirect Г-K and Г-Q interlayer excitons.Our results suggest that twisted MoSe_(2) homobilayers are an intriguing platform for engineering interlayer exciton states,which may shed light on future atomically thin optoelectronic applications.展开更多
Dear editor,As of 2023,the domestic cat population in China reached 65 million,surpassing dogs to become the most numerous companion animal in the country.Feline calicivirus(FCV)infection,one of the three most prevale...Dear editor,As of 2023,the domestic cat population in China reached 65 million,surpassing dogs to become the most numerous companion animal in the country.Feline calicivirus(FCV)infection,one of the three most prevalent infectious diseases in cats,poses a severe threat to feline health.FCV,classified under the Caliciviridae family(genus Vesivirus).展开更多
Preterm birth and suboptimal fetal growth remain significant perinatal challenges worldwide.Recent data indicate that China's perinatal profile has improved due to reductions in preterm birth rates.However,the cou...Preterm birth and suboptimal fetal growth remain significant perinatal challenges worldwide.Recent data indicate that China's perinatal profile has improved due to reductions in preterm birth rates.However,the country has a 6.5%prevalence of small-for-gestational-age(SGA),ranking fifth globally in total SGA birth numbers^([1,2]).展开更多
Increasing the number of atoms that interact with microwave fields represents a promising strategy for enhancing the sensitivity of Rydberg atom-based superheterodyne receivers.Nevertheless,the practical implementatio...Increasing the number of atoms that interact with microwave fields represents a promising strategy for enhancing the sensitivity of Rydberg atom-based superheterodyne receivers.Nevertheless,the practical implementation of this approach is impeded by adverse effects such as excitation saturation of Rydberg atoms and power broadening.Here,we demonstrate enhanced microwave field measurements based on two specific velocity groups of atoms,simultaneously addressed by dual-channel probe beams in a Sagnac loop interferometer.The application of resonance detuning in two-photon excitation enables selective addressing of atoms moving along the beam direction,thereby significantly mitigating atomic transit noise.At 7.97 GHz,our method yields a 3 dB improvement in signal-to-noise ratio(SNR),achieving a sensitivity of 10.7 nV·cm^(−1)·Hz^(−1/2).This approach offers a viable pathway to further improve the sensitivity of Rydberg atom-based microwave electrometers.展开更多
Accessible communication based on sign language recognition(SLR)is the key to emergency medical assistance for the hearing-impaired community.Balancing the capture of both local and global information in SLR for emerg...Accessible communication based on sign language recognition(SLR)is the key to emergency medical assistance for the hearing-impaired community.Balancing the capture of both local and global information in SLR for emergency medicine poses a significant challenge.To address this,we propose a novel approach based on the inter-learning of visual features between global and local information.Specifically,our method enhances the perception capabilities of the visual feature extractor by strategically leveraging the strengths of convolutional neural network(CNN),which are adept at capturing local features,and visual transformers which perform well at perceiving global features.Furthermore,to mitigate the issue of overfitting caused by the limited availability of sign language data for emergency medical applications,we introduce an enhanced short temporal module for data augmentation through additional subsequences.Experimental results on three publicly available sign language datasets demonstrate the efficacy of the proposed approach.展开更多
国外社区代际共融研究历经长期体系建构,对中国相关研究具有重要借鉴价值。该文以“客观文献追踪”为视角,选取2004年—2023年“Web of Science”数据库中的国外文献,利用CiteSpace软件绘制知识图谱,分析学科及期刊分布、理论基础与研...国外社区代际共融研究历经长期体系建构,对中国相关研究具有重要借鉴价值。该文以“客观文献追踪”为视角,选取2004年—2023年“Web of Science”数据库中的国外文献,利用CiteSpace软件绘制知识图谱,分析学科及期刊分布、理论基础与研究热点。研究发现,国外社区代际共融研究已构建完整网络体系并持续拓展,研究视角多元且发展迅速,逐渐拓展至家庭、社区、社会等多个领域。其中,“代际共融与人的关系”“社区和邻里重构”以及“公众参与与政策引导”是当前的研究热点。旨在丰富社区代际共融研究视角与方法,为拓展我国相关研究体系提供参考。展开更多
针对长定子直线同步电机(long-stator linear synchronous motor,简称LSLSM)定子绕组匝间短路(stator winding inter-turn short circuit,简称ITSC)故障在强噪声与复杂工况下特征微弱,传统电机电流特性分析方法难以实现早期精准检测的问...针对长定子直线同步电机(long-stator linear synchronous motor,简称LSLSM)定子绕组匝间短路(stator winding inter-turn short circuit,简称ITSC)故障在强噪声与复杂工况下特征微弱,传统电机电流特性分析方法难以实现早期精准检测的问题,提出了一种基于迭代自适应多重同步压缩变换(iterative adaptive multiple synchronous compression of transform,简称IAMST)的时频分析方法,通过最优路径搜索与时频脊线压缩提升故障特征能量聚集性,实现LSLSM定子绕组故障的可靠识别。首先,建立常导高速磁浮机-电-磁耦合模型,揭示ITSC故障下d轴电流残差信号以二次谐波为主导的故障特征机理,并分析其对车辆牵引性能的影响;其次,提出IAMST算法,采用改进型Viterbi算法结合动态指数平滑预测,实现强噪声环境下瞬时频率(instantaneous frequency,简称IF)的精准初始化;然后,通过迭代压缩细化机制,将时频能量聚焦于真实IF脊线,克服传统方法的交叉干扰与噪声敏感性问题;最后,基于硬件在环(hardware-in-the-loop,简称HIL)平台开展故障注入实验。结果表明,IAMST方法为非平稳信号时频分析提供了一种抗噪性强、特征分辨率高的解决方案,为磁浮列车LSLSM定子绕组早期故障检测提供了可靠的技术支撑。展开更多
基金funded by the National Natural Science Foundation of China(Grant Nos.22005167 and 21905152)the Shandong Provincial Natural Science Foundation of China(Grant Nos.ZR2020QB125 and ZR2020MB045)+1 种基金the China Postdoctoral Science Foundation(Grant Nos.2021M693256,2021T140687 and 2022M713249)the Qingdao Postdoctoral Applied Research Project and the Youth Innovation Team Project for Talent Introduction and Cultivation in Universities of Shandong Province。
文摘As an emerging member of the two-dimensional(2D)material family,V_(2)CT_(X)MXene shows great potential in the application of lithium-ion capacitors(LICs)due to its unique structure and excellent electrical conductivity.However,severe nanosheets stacking and intra-layer transport barriers have limited the further development of V_(2)CT_(X)MXene-based materials.Herein,we prepared Kions and–O functional group co-modified V_(2)CT_(X)MXene(VCT-K)and further incorporated it with single-walled carbon nanotube(SWCNT),obtaining freestanding V_(2)CT_(X)composite films(VCT-K@C)with the 3D conductive network.Significantly,K+ions were introduced into V_(2)CT_(X)MXene to stabilize the interlayer structure and prevent the aggregation of nanosheets,the terminal group of–O was controllably modified on the surface of MXene to improve the Li+ions storage reversible capacities and the SWCNT acted as the bridge between MXene nanosheets to opens up the channels for ion/electron transportation in the longitudinal direction.Benefited from the synergistic effect of VCT-K and SWCNT,the VCT-K@C exhibits superior reversible specific capacities of 671.8 mA h g^(-1)at 0.1 A g^(-1)and 318 mA h g^(-1)at 1.0 A g^(-1).Furthermore,the assembled LICs with VCT-K@C anode coupling activated carbon(AC)cathode deliver an outstanding power density of 19.0 kW kg^(-1)at 67.4 Wh kg^(-1),a high energy density of 140.5 Wh kg^(-1)at 94.8 W kg^(-1)and a stable capacitance retention of 86%after 6000 cycles at 10 A g^(-1).Such unique structures and excellent electrochemical properties are expected to pave the way for the large-scale application in LICs of MXene-based materials.
基金supported by the National Key R&D Program of China(No.2023YFF1500600)the National Natural Science Foun-dation of China(Nos.12004259,12204287)+3 种基金China Postdoc-toral Science Foundation(Grant No.2022M723215)Zheng Vitto Han acknowledges the support of the Fund for Shanxi“1331 Project”Key Subjects Construction,and the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302003)Kenji Watanabe and Takashi Taniguchi acknowledge support from the JSPS KAKENHI(Grant Nos.20H00354 and 23H02052)the World Premier International Research Center Initiative(WPI),MEXT,Japan.
文摘Twist,the very degree of freedom in van der Waals heterostructures,offers a compelling avenue to manipulate and tailor their electrical and optical characteristics.In particular,moirépatterns in twisted homobilayer transition metal dichalcogenides(TMDs)lead to zone folding and miniband formation in the resulting electronic bands,holding the promise to exhibit inter-layer excitonic optical phenomena.Although some experiments have shown the existence of twist-angle-dependent intra-and inter-layer excitons in twisted MoSe2 homobilayers,electrical control of the interlayer excitons in MoSe_(2) is relatively under-explored.Here,we show the signatures of the moiréeffect on intralayer and interlayer excitons in 2H-stacked twisted MoSe2 homobilayers.Doping-and electric field-dependent photoluminescence mea-surements at low temperatures give evidence of the momentum-direct K-K intralayer excitons,and the momentum-indirect Г-K and Г-Q interlayer excitons.Our results suggest that twisted MoSe_(2) homobilayers are an intriguing platform for engineering interlayer exciton states,which may shed light on future atomically thin optoelectronic applications.
基金supported by grants from the National Key Research and Development Program of China(Grant No.2022YFD1800100)National Natural Science Foundation of China(Grant No.32272982)Natural Science Foundation of Shanghai(Grant No.23ZR1477100).
文摘Dear editor,As of 2023,the domestic cat population in China reached 65 million,surpassing dogs to become the most numerous companion animal in the country.Feline calicivirus(FCV)infection,one of the three most prevalent infectious diseases in cats,poses a severe threat to feline health.FCV,classified under the Caliciviridae family(genus Vesivirus).
基金funded by the Natural Science Foundation of Hunan Province(grant number 2024JJ5283 to XH)。
文摘Preterm birth and suboptimal fetal growth remain significant perinatal challenges worldwide.Recent data indicate that China's perinatal profile has improved due to reductions in preterm birth rates.However,the country has a 6.5%prevalence of small-for-gestational-age(SGA),ranking fifth globally in total SGA birth numbers^([1,2]).
基金supported by the National Key R&D Program of China(Grant No.2022YFA1404003)the National Natural Science Foundation of China(Grant Nos.T2495252,12104279,and 123B2062)+2 种基金the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302100)the Fund for Shanxi“1331 Project”Key Subjects Constructionthe Bairen Project of Shanxi Province。
文摘Increasing the number of atoms that interact with microwave fields represents a promising strategy for enhancing the sensitivity of Rydberg atom-based superheterodyne receivers.Nevertheless,the practical implementation of this approach is impeded by adverse effects such as excitation saturation of Rydberg atoms and power broadening.Here,we demonstrate enhanced microwave field measurements based on two specific velocity groups of atoms,simultaneously addressed by dual-channel probe beams in a Sagnac loop interferometer.The application of resonance detuning in two-photon excitation enables selective addressing of atoms moving along the beam direction,thereby significantly mitigating atomic transit noise.At 7.97 GHz,our method yields a 3 dB improvement in signal-to-noise ratio(SNR),achieving a sensitivity of 10.7 nV·cm^(−1)·Hz^(−1/2).This approach offers a viable pathway to further improve the sensitivity of Rydberg atom-based microwave electrometers.
基金supported by the National Natural Science Foundation of China(No.62376197)the Tianjin Science and Technology Program(No.23JCYBJC00360)the Tianjin Health Research Project(No.TJWJ2025MS045).
文摘Accessible communication based on sign language recognition(SLR)is the key to emergency medical assistance for the hearing-impaired community.Balancing the capture of both local and global information in SLR for emergency medicine poses a significant challenge.To address this,we propose a novel approach based on the inter-learning of visual features between global and local information.Specifically,our method enhances the perception capabilities of the visual feature extractor by strategically leveraging the strengths of convolutional neural network(CNN),which are adept at capturing local features,and visual transformers which perform well at perceiving global features.Furthermore,to mitigate the issue of overfitting caused by the limited availability of sign language data for emergency medical applications,we introduce an enhanced short temporal module for data augmentation through additional subsequences.Experimental results on three publicly available sign language datasets demonstrate the efficacy of the proposed approach.
文摘国外社区代际共融研究历经长期体系建构,对中国相关研究具有重要借鉴价值。该文以“客观文献追踪”为视角,选取2004年—2023年“Web of Science”数据库中的国外文献,利用CiteSpace软件绘制知识图谱,分析学科及期刊分布、理论基础与研究热点。研究发现,国外社区代际共融研究已构建完整网络体系并持续拓展,研究视角多元且发展迅速,逐渐拓展至家庭、社区、社会等多个领域。其中,“代际共融与人的关系”“社区和邻里重构”以及“公众参与与政策引导”是当前的研究热点。旨在丰富社区代际共融研究视角与方法,为拓展我国相关研究体系提供参考。
文摘针对长定子直线同步电机(long-stator linear synchronous motor,简称LSLSM)定子绕组匝间短路(stator winding inter-turn short circuit,简称ITSC)故障在强噪声与复杂工况下特征微弱,传统电机电流特性分析方法难以实现早期精准检测的问题,提出了一种基于迭代自适应多重同步压缩变换(iterative adaptive multiple synchronous compression of transform,简称IAMST)的时频分析方法,通过最优路径搜索与时频脊线压缩提升故障特征能量聚集性,实现LSLSM定子绕组故障的可靠识别。首先,建立常导高速磁浮机-电-磁耦合模型,揭示ITSC故障下d轴电流残差信号以二次谐波为主导的故障特征机理,并分析其对车辆牵引性能的影响;其次,提出IAMST算法,采用改进型Viterbi算法结合动态指数平滑预测,实现强噪声环境下瞬时频率(instantaneous frequency,简称IF)的精准初始化;然后,通过迭代压缩细化机制,将时频能量聚焦于真实IF脊线,克服传统方法的交叉干扰与噪声敏感性问题;最后,基于硬件在环(hardware-in-the-loop,简称HIL)平台开展故障注入实验。结果表明,IAMST方法为非平稳信号时频分析提供了一种抗噪性强、特征分辨率高的解决方案,为磁浮列车LSLSM定子绕组早期故障检测提供了可靠的技术支撑。
