In this paper, an archetypal aseismic system is proposed with 2-degree of freedom based on a smooth and discontinuous(SD)oscillator to avoid the failure of electric power system under the complex excitation of seismic...In this paper, an archetypal aseismic system is proposed with 2-degree of freedom based on a smooth and discontinuous(SD)oscillator to avoid the failure of electric power system under the complex excitation of seismic waves. This model comprises two vibration isolation units for the orthogonal horizontal directions, and each of them admits the stable quasi-zero stiffness(SQZS)with a pair of inclined linear elastic springs. The equation of motion is formulated by using Lagrange equation, and the SQZS condition is obtained by optimizing the parameters of the system. The analysis shows that the system behaves a remarkable vibration isolation performance with low resonant frequency and a large stroke of SQZS interval. The experimental investigations are carried out to show a high sonsistency with the theoretical results, which demonstrates the improvement of aseismic behavior of the proposed model under the seismic wave.展开更多
Femtosecond laser technology has attracted significant attention from the viewpoints of fundamental and application;especially femtosecond laser processing materials present the unique mechanism of laser-material inte...Femtosecond laser technology has attracted significant attention from the viewpoints of fundamental and application;especially femtosecond laser processing materials present the unique mechanism of laser-material interaction.Under the extreme nonequilibrium conditions imposed by femtosecond laser irradiation,many fundamental questions concerning the physical origin of the material removal process remain unanswered.In this review,cutting-edge ultrafast dynamic observation techniques for investigating the fundamental questions,including timeresolved pump-probe shadowgraphy,ultrafast continuous optical imaging,and four-dimensional ultrafast scanning electron microscopy,are comprehensively surveyed.Each technique is described in depth,beginning with its basic principle,followed by a description of its representative applications in laser-material interaction and its strengths and limitations.The consideration of temporal and spatial resolutions and panoramic measurement at different scales are two major challenges.Hence,the prospects for technical advancement in this field are discussed finally.展开更多
Numerous valuable studies on electron dynamics have focussed on the extraordinary properties of molybdenum disulfide(MoS_(2));however,most of them were confined to the level below the damage threshold.Here the electro...Numerous valuable studies on electron dynamics have focussed on the extraordinary properties of molybdenum disulfide(MoS_(2));however,most of them were confined to the level below the damage threshold.Here the electron dynamics of MoS_(2) under intense ultrafast laser irradiation was investigated by experiments and simulations.Two kinds of ablation mechanisms were revealed,which led to two distinct types of electron dynamics and final ablation morphology.At a higher fluence,the emergence of superheated liquid induced a dramatic change in the transient reflectivity and micro-honeycomb structures.At a lower fluence,the material was just removed by sublimation,and the ablation structure was relatively flat.X-ray photoelectron spectroscopic(XPS)measurements demonstrated that thermal decomposition only occurred at the higher fluence.Furthermore,a theoretical model was developed to deeply reveal the ultrafast dynamics of MoS_(2) ablation.The simulation results were in good agreement with the temporal and spatial reflectivity distribution obtained from the experiment.The electron and lattice temperature evolution was also obtained to prove the ablation mechanism.Our results revealed ultrafast dynamics of MoS_(2) above the damage threshold and are helpful for understanding the interaction mechanism between MoS_(2) and intense ultrafast lasers,as well as for MoS_(2) processing applications.展开更多
Immune checkpoint inhibitors(ICIs),especially inhibitors of the PD-1/PD-L1 axis,have significantly affected the outcomes of patients with lung cancer.Nivolumab and pembrolizumab have been approved as PD-1 blocking ant...Immune checkpoint inhibitors(ICIs),especially inhibitors of the PD-1/PD-L1 axis,have significantly affected the outcomes of patients with lung cancer.Nivolumab and pembrolizumab have been approved as PD-1 blocking antibodies,whereas atezolizumab,avelumab,and durvalumab are approved as PD-L1 blocking antibodies by the United States Food and Drug Administration.However,which patient may benefit the most and how to identify patients at risk of primary or acquired resistance has not been completely defined.Meanwhile,close attention has been paid to the ongoing international and domestic clinical trials in Chinese patients with lung cancer.This review aimed to provide deep insight into the effectiveness of PD-1/PD-L1 inhibitors in patients with lung cancer,including the current settings for varied disease status,the predictive biomarkers,the resistance to ICIs,and the ongoing clinical trials in Chinese patients.展开更多
基金the financial support from the National Natural Science Foundation of China(Grant Nos.11572096,11732006)
文摘In this paper, an archetypal aseismic system is proposed with 2-degree of freedom based on a smooth and discontinuous(SD)oscillator to avoid the failure of electric power system under the complex excitation of seismic waves. This model comprises two vibration isolation units for the orthogonal horizontal directions, and each of them admits the stable quasi-zero stiffness(SQZS)with a pair of inclined linear elastic springs. The equation of motion is formulated by using Lagrange equation, and the SQZS condition is obtained by optimizing the parameters of the system. The analysis shows that the system behaves a remarkable vibration isolation performance with low resonant frequency and a large stroke of SQZS interval. The experimental investigations are carried out to show a high sonsistency with the theoretical results, which demonstrates the improvement of aseismic behavior of the proposed model under the seismic wave.
基金supported by the National Natural Science Foundation of China under Grant Nos.51975054,61605140 and 11704028the National Key R&D Program of China(2017YFB1104300)。
文摘Femtosecond laser technology has attracted significant attention from the viewpoints of fundamental and application;especially femtosecond laser processing materials present the unique mechanism of laser-material interaction.Under the extreme nonequilibrium conditions imposed by femtosecond laser irradiation,many fundamental questions concerning the physical origin of the material removal process remain unanswered.In this review,cutting-edge ultrafast dynamic observation techniques for investigating the fundamental questions,including timeresolved pump-probe shadowgraphy,ultrafast continuous optical imaging,and four-dimensional ultrafast scanning electron microscopy,are comprehensively surveyed.Each technique is described in depth,beginning with its basic principle,followed by a description of its representative applications in laser-material interaction and its strengths and limitations.The consideration of temporal and spatial resolutions and panoramic measurement at different scales are two major challenges.Hence,the prospects for technical advancement in this field are discussed finally.
基金supported by the National Natural Science Foundation of China(Grant No.11704028)the National Key R&D Program of China(Grant No.2017YFB1104300).
文摘Numerous valuable studies on electron dynamics have focussed on the extraordinary properties of molybdenum disulfide(MoS_(2));however,most of them were confined to the level below the damage threshold.Here the electron dynamics of MoS_(2) under intense ultrafast laser irradiation was investigated by experiments and simulations.Two kinds of ablation mechanisms were revealed,which led to two distinct types of electron dynamics and final ablation morphology.At a higher fluence,the emergence of superheated liquid induced a dramatic change in the transient reflectivity and micro-honeycomb structures.At a lower fluence,the material was just removed by sublimation,and the ablation structure was relatively flat.X-ray photoelectron spectroscopic(XPS)measurements demonstrated that thermal decomposition only occurred at the higher fluence.Furthermore,a theoretical model was developed to deeply reveal the ultrafast dynamics of MoS_(2) ablation.The simulation results were in good agreement with the temporal and spatial reflectivity distribution obtained from the experiment.The electron and lattice temperature evolution was also obtained to prove the ablation mechanism.Our results revealed ultrafast dynamics of MoS_(2) above the damage threshold and are helpful for understanding the interaction mechanism between MoS_(2) and intense ultrafast lasers,as well as for MoS_(2) processing applications.
基金Supported by the National Key Research and Development Program of China(2016YFC1303300)the National Natural Science Foundation of China(81672272)+2 种基金the Shanghai Municipal Science and Technology Commission Research Project(17431906103)the Shanghai Chest Hospital Project of Collaborative Innovation(YJXT20190105)and the Clinical Research Plan of Shanghai Hospital Development Center(SHDC)(16CR3005A).
文摘Immune checkpoint inhibitors(ICIs),especially inhibitors of the PD-1/PD-L1 axis,have significantly affected the outcomes of patients with lung cancer.Nivolumab and pembrolizumab have been approved as PD-1 blocking antibodies,whereas atezolizumab,avelumab,and durvalumab are approved as PD-L1 blocking antibodies by the United States Food and Drug Administration.However,which patient may benefit the most and how to identify patients at risk of primary or acquired resistance has not been completely defined.Meanwhile,close attention has been paid to the ongoing international and domestic clinical trials in Chinese patients with lung cancer.This review aimed to provide deep insight into the effectiveness of PD-1/PD-L1 inhibitors in patients with lung cancer,including the current settings for varied disease status,the predictive biomarkers,the resistance to ICIs,and the ongoing clinical trials in Chinese patients.
