Frequency-modulated continuous-wave(FMCW)light sources are essential components for coherent light detection and ranging(LiDAR),which is ubiquitously utilized in autonomous driving,industrial monitoring,and geological...Frequency-modulated continuous-wave(FMCW)light sources are essential components for coherent light detection and ranging(LiDAR),which is ubiquitously utilized in autonomous driving,industrial monitoring,and geological remote sensing.Traditional FMCW LiDAR systems often face challenges in achieving high frequencysweep linearity and large excursion,which are critical for accurate distance and velocity measurements.Here,we propose a self-injection locked laser with frequency-shifted feedback to generate ultra-linear and wideband FMCW light.A record-low relative frequency nonlinearity of 6.4×10^(-7)is achieved when the frequency excursion is 100 GHz and the repetition frequency is 1 kHz.In the LiDAR test,a range resolution of 1.6 mm and a velocity accuracy of 3 mm/s at 300 m distance are demonstrated,and those of 8.1 mm and 6 mm/s at 1 km distance are also obtained.The reported FMCW light source provides not only enhanced performance in coherent LiDAR,but also utilization potential in various high-precision measurement scenarios.展开更多
On-chip couplers are essential for coupling free-space electromagnetic waves into sub-wavelength semiconductor devices and enhancing light-matter interactions.However,the couplers used in existing single field-effect ...On-chip couplers are essential for coupling free-space electromagnetic waves into sub-wavelength semiconductor devices and enhancing light-matter interactions.However,the couplers used in existing single field-effect transistor(FET)detectors exhibit poor response over wide frequency ranges,making the detection of ultra-wideband weak signals highly challenging.In this work,we introduce a meta-array coupler for terahertz detectors based on field-effect transistors,which demonstrates exceptional coupling asymmetry beneath the gate.To optimize the meta-array structure for high gain across an ultra-wide frequency range,we propose a hybrid long short-term memory–multi-layer perceptron(LSTM-MLP)neural network for the detector’s on-chip coupler.This method enables accurate and rapid prediction of the enhanced spectra of meta-atoms,facilitating efficient conversion from structural parameters to resonance frequencies.Compared to traditional dipole couplers,the proposed metacoupler generates strong localized electric field enhancement through dipole resonance,achieving a mixing factor asymmetry up to 246 times higher near 660 GHz and an antenna factor enhancement of approximately 50 times.The meta-array coupled FET terahertz detector achieves ultra-wideband resonance enhancement from 350 to1000 GHz.This hardware architecture and hybrid LSTM-MLP neural network are expected to overcome the limitations of current FET-based detectors in coupling efficiency,bridging the performance gap toward ultra-sensitive detection applications.展开更多
Autonomous machines(AMs)are poised to possess human-like moral cognition,yet their morality is often pre-programmed for safety.This raises the question of whether the morality intended by programmers aligns with their...Autonomous machines(AMs)are poised to possess human-like moral cognition,yet their morality is often pre-programmed for safety.This raises the question of whether the morality intended by programmers aligns with their actions during actual operation,a crucial consideration for a future society with both humans and AMs.Investigating this,we use a micro-robot swarm in a simulated fire scenario,with 180 participants,including 102 robot programmers,completing moral questionnaires and participating in virtual escape trials.These exercises mirror common societal moral dilemmas.Our comparative analysis reveals a“morality gap”between programming presets and real-time operation,primarily influenced by uncertainty about the future and heightened by external pressures,especially social punishment.This discrepancy suggests that operational morality can diverge from programmed intentions,underlining the need for careful AM design to foster a collaborative and efficient society.展开更多
In this paper we present the science potential of the enhanced X-ray Timing and Polarimetry(eXTP)mission,in its new configuration,for studies of strongly magnetized compact objects.We discuss the scientific potential ...In this paper we present the science potential of the enhanced X-ray Timing and Polarimetry(eXTP)mission,in its new configuration,for studies of strongly magnetized compact objects.We discuss the scientific potential of eXTP for quantum electrodynamic(QED)studies,especially leveraging the recent observations made with the NASA IXPE mission.Given eXTP’s unique combination of timing,spectroscopy,and polarimetry,we focus on the perspectives for physics and astrophysics studies of strongly magnetized compact objects,such as magnetars and accreting X-ray pulsars.Developed by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Sciences,the eXTP mission is expected to launch in early 2030.展开更多
In this white paper,we present the potential of the enhanced X-ray timing and polarimetry(eXTP)mission to constrain the equation of state of dense matter in neutron stars,exploring regimes not directly accessible to t...In this white paper,we present the potential of the enhanced X-ray timing and polarimetry(eXTP)mission to constrain the equation of state of dense matter in neutron stars,exploring regimes not directly accessible to terrestrial experiments.By observing a diverse population of neutron stars—including isolated objects,X-ray bursters,and accreting systems—eXTP’s unique combination of timing,spectroscopy,and polarimetry enables high-precision measurements of compactness,spin,surface temperature,polarimetric signals,and timing irregularity.These multifaceted observations,combined with advances in theoretical modeling,pave the way toward a comprehensive description of the properties and phases of dense matter from the crust to the core of neutron stars.Under development by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Sciences,the eXTP mission is planned to be launched in early 2030.展开更多
Background: Since infections can lead to adverse outcomes in autoimmune bullous diseases (AIBD), this study aimed to analyze infection characteristics in AIBD, predict infection risk factors and provide probable sugge...Background: Since infections can lead to adverse outcomes in autoimmune bullous diseases (AIBD), this study aimed to analyze infection characteristics in AIBD, predict infection risk factors and provide probable suggestions to infection prevention, which will spot a light on early discovery and prevention of infections in AIBD patients. Methods: This is a retrospective study of the medical records of inpatients diagnosed with AIBD at the Department of Infectious Diseases and Dermatology, Huashan Hospital from January 2017 to December 2021. We collected patients’ clinical manifestations and laboratory examination results. Risk factors for infections were evaluated using multivariate logistic regression. Results: A total of 263 AIBD patients were included in the study. The overall incidence of infection was 42.2% (111/263). Pemphigus had a higher infection rate (74/142, 52.1%) than bullous pemphigoid (37/121, 30.6%). Among the patients with infections, 49.5% (55/111) had bacterial infections, 13.5% (15/111) had fungal infections, 2.7% (3/111) had virus infections, and 34.2% (38/111) had mixed infections. Staphylococcus aureus and Candida were the most common pathogens in localized infections, while Cryptococcus and Candida were predominant in systemic infections. In the multivariate logistic model, pemphigus (odds ratio [OR] = 2.56, 95% confidence interval [CI] 1.41-4.63), hypoalbuminemia (OR = 3.78, 95% CI 1.68-8.50), and systemic glucocorticoid treatment (OR = 4.67, 95% CI 2.51-8.68) were independent risk factors for infection in AIBD patients. Bullous pemphigoid (OR = 3.99, 95% CI 1.03-15.45), high-dose (average > 24 mg/day) compared to low-dose (average ≤ 6 mg/day) and medium-dose (average 6-24 mg/day) systemic glucocorticoid treatment (OR = 19.31, 95% CI 3.32-112.28, and OR = 5.71, 95% CI 1.37-23.79) were associated with increased risk factors of systemic infection in AIBD patients with systemic glucocorticoid treatment. A methylprednisolone dose averaging 14 mg/day over the past three months had a 75.0% positive predictive value for infections in AIBD patients. Conclusions: The incidence of infection in AIBD patients is high, with a broad spectrum of pathogens and infection locations. AIBD patients undergoing systemic glucocorticoid treatment, especially those receiving high doses in the previous three months, should be cautious about infection.展开更多
We present a polarization-maintaining PANDA ring-core fiber(PM-PRCF) characterized by the combination of a ring-core structure with two stress-applying rods. This special fiber design separates the adjacent modes and ...We present a polarization-maintaining PANDA ring-core fiber(PM-PRCF) characterized by the combination of a ring-core structure with two stress-applying rods. This special fiber design separates the adjacent modes and avoids the cutoff of the higher-order modes, which is a common problem in elliptical core polarization-maintaining few-mode fibers. Using a high-contrast index ring and stress-induced birefringence, the PM-PRCF features support for 10 vector modes, with effective refractive index separations from their adjacent modes >10^(-4).Broadband performance is investigated subsequently over a wide wavelength range from 1500 to 1630 nm.The proposed fiber is targeted at applications in space-division multiplexing while eliminating the complex multiple-input multiple-output signal processing.展开更多
Solitons are self-reinforcing localized wave packets that manifest in the major areas of nonlinear science,from optics to biology and Bose-Einstein condensates.Recently,optically driven dissipative solitons have attra...Solitons are self-reinforcing localized wave packets that manifest in the major areas of nonlinear science,from optics to biology and Bose-Einstein condensates.Recently,optically driven dissipative solitons have attracted great attention for the implementation of the chip-scale frequency combs that are decisive for communications,spectroscopy,neural computing,and quantum information processing.In the current understanding,the generation of temporal solitons involves the chromatic dispersion as a key enabling physical effect,acting either globally or locally on the cavity dynamics in a decisive way.Here,we report on a novel class of solitons,both theoretically and experimentally,which builds up in spectrally confined optical cavities when dispersion is practically absent,both globally and locally.Precisely,the interplay between the Kerr nonlinearity and spectral filtering results in an infiinite hierarchy of eigenfunctions which,combined with optical gain,allow for the generation of stable dispersion-less dissipative solitons in a previously unexplored regime.When the filter order tends to infinity,we find an unexpected link between dissipative and conservative solitons,in the form of Nyquist-pulse-like solitons endowed with an ultra-flat spectrum.In contrast to the conventional dispersion-enabled nonlinear Schr?dinger solitons,these dispersion-less Nyquist solitons build on a fully confined spectrum and their energy scaling is not constrained by the pulse duration.Dispersion-less soliton molecules and their deterministic transitioning to single solitons are also evidenced.These findings broaden the fundamental scope of the dissipative soliton paradigm and open new avenues for generating soliton pulses and frequency combs endowed with unprecedented temporal and spectral features.展开更多
A broadband photonic analog-to-digital converter（ADC） for X-band radar applications is proposed and experimentally demonstrated. An X-band signal with arbitrary waveform and a bandwidth up to 2 GHz can be synchronou...A broadband photonic analog-to-digital converter（ADC） for X-band radar applications is proposed and experimentally demonstrated. An X-band signal with arbitrary waveform and a bandwidth up to 2 GHz can be synchronously sampled and processed due to the optical sampling structure. In the experiment, the chirp signal centered at 9 GHz with a bandwidth of 1.6 GHz is sampled and down-converted with a signal-to-noise ratio of 7.20 d B and an improved noise figure. Adopting the photonic ADC in the radar receiver and the above signal as the transmitted radar signal, an X-band inverse synthetic aperture radar system is set up, and the range and cross-range resolutions of 9.4 and 8.3 cm are obtained, respectively.展开更多
Microcomb generation with simultaneous χ2 and χ3 nonlinearities brings new possibilities for ultrabroadband and potentially self-referenced integrated comb sources. However, the evolution of the intracavity field in...Microcomb generation with simultaneous χ2 and χ3 nonlinearities brings new possibilities for ultrabroadband and potentially self-referenced integrated comb sources. However, the evolution of the intracavity field involving multiple nonlinear processes shows complex dynamics that are still poorly understood. Here, we report on strong soliton regulation induced by fundamental–second-harmonic(FD-SH) mode coupling. The formation of solitons from chaos is extensively investigated based on coupled Lugiato–Lefever equations. The soliton generation shows more deterministic behaviors in the presence of FD-SH mode interaction, which is in sharp contrast with the usual cases where the soliton number and relative locations are stochastic. Deterministic single soliton transition, soliton binding, and prohibition are observed, depending on the phase-matching condition and coupling coefficient between the fundamental and second-harmonic waves. Our finding provides important new insights into the soliton dynamics in microcavities with simultaneous χ~2and χ~3nonlinearities and can be immediate guidance for broadband soliton comb generation with such platforms.展开更多
With the increase in large-scale incidents in real life, crowd evacuation plays a pivotal role in ensuring the safety of human crowds during emergency situations. The behavior patterns of crowds are well rendered by e...With the increase in large-scale incidents in real life, crowd evacuation plays a pivotal role in ensuring the safety of human crowds during emergency situations. The behavior patterns of crowds are well rendered by existing crowd dynamics models. However, most related studies ignore the information perception of pedestrians.To overcome this issue, we develop a visual information based social force model to simulate the interpretable evacuation process from the perspective of visual perception. Numerical experiments indicate that the evacuation efficiency and decision-making ability promote rapidly within a small range with the increase in unbalanced prior knowledge. The propagation of acceleration behavior caused by emergencies is asymmetric due to the anisotropy of visual information. Therefore, this model effectively characterizes the effect of visual information on crowd evacuation and provides new insights into the information perception of individuals in complex scenarios.展开更多
A photonic approach to concurrently measure the angle-of-arrival(AOA) and the chirp rate of a linear frequency modulated(LFM) signal is proposed and experimentally demonstrated. The measurement is achieved by estimati...A photonic approach to concurrently measure the angle-of-arrival(AOA) and the chirp rate of a linear frequency modulated(LFM) signal is proposed and experimentally demonstrated. The measurement is achieved by estimating the differential frequency of a two-tone signal output by a dual-parallel Mach–Zehnder modulator and an additional asymmetry Mach–Zehnder interferometer. Experiments show that the AOA and the chirp rate are measured simultaneously, with an AOA measurement error of ?0.1° at an signal-to-noise ratio(SNR) of 9.6 d B.When the SNR is-10.4 d B, the AOA error is ?1.3°, and the chirp rate, measured as 210.2 ? 1.5 Hz∕ps, has a standard deviation of 0.7%. The measured chirp rate agrees well with the real LFM signal.展开更多
This paper presents an introduction to the researches in microwave photonics based packages and its application, a 973 project （No. 2012CB315600）, which focuses on addressing new requirements for millimeter wave （...This paper presents an introduction to the researches in microwave photonics based packages and its application, a 973 project （No. 2012CB315600）, which focuses on addressing new requirements for millimeter wave （MMW） system to work with higher frequency, wider bandwidth, larger dynamic range and longer distance of signal distribution. Its key scientific problems, main research contents and objectives are briefed, and some latest achievements by the project team, including generation of linear frequency modulation wave （LFMW）, tunable optoelectronic oscillator （OEO） with lower phase noise, reconfigurable filter with higher Q value, time delay line with wider frequency range, down conversion with gain, and local oscillator （LO） transmission with stable phase, are introduced briefly.展开更多
Drug safety management is an important issue in China drug management system and attracts great attentions from the whole society.In order to reduce drug incident,this study discusses some important elements associate...Drug safety management is an important issue in China drug management system and attracts great attentions from the whole society.In order to reduce drug incident,this study discusses some important elements associated with China drug safety management system and analyzes the data collected by questionnaires.Besides,a methodology for rating the important elements is described and applied.The non-structural fuzzy group decision method not only considers the insufficient precise information but also combines the opinions of different kinds of respondents in China’s four municipalities.The results indicate that the sample systems are the most important in these important elements,and the order of importance is sampling systems,licensing systems,traceability systems,transaction models,pharmacovigilance and emergence management.This study not only points out the important ranking of the pivotal elements in China drug safety management but also gives some specific proposals about how to enhance drug safety management in China.展开更多
It is a pioneering work to use a Markov chain model to study the pedestrian escape route without visibility.In this paper,based on the Markov chain probability transition matrix,the algorithms with random numbers and ...It is a pioneering work to use a Markov chain model to study the pedestrian escape route without visibility.In this paper,based on the Markov chain probability transition matrix,the algorithms with random numbers and the spatial-grid,an escape route in a limited invisible space is obtained.Six pace states(standing,crawling,walking,leaping,jogging,and running)are applied to describe the characteristics of pedestrian behaviors.Besides,eight main direction changes are used to describe the transition characteristic of a pedestrian.At the same time,this paper analyzes the escape route from two views,i.e.,pedestrian pace states and directions.The research results show that the Markov chain model is more realistic as a means of studying pedestrian escape routes.展开更多
Three-dimensional(3D)imaging radar is an advanced sensor applied in space surveillance and target recognition for supplying 3D geometric features and supporting visualization.However,high 3D resolution requires both b...Three-dimensional(3D)imaging radar is an advanced sensor applied in space surveillance and target recognition for supplying 3D geometric features and supporting visualization.However,high 3D resolution requires both broadband operation and a large 2D aperture,which are difficult and complex for conventional radars.This paper presents a photonics-enabled distributed multiple-input and multiple-output(MIMO)radar with a centralized architecture.By use of photonic multi-dimensional multiplexing,multi-channel signal generation and reception are implemented on a shared reference signal in a central office,enabling a highly coherent network with a simple structure.Additionally,a sparse array and a synthetic aperture are combined to efficiently reduce the required transceivers,further weakening the dilemma between system complexity and angular resolution.A 4×4 MIMO radar is established and evaluated in field tests.A high-resolution 3D image of a non-cooperative aircraft is obtained,in which rich details are displayed.From a comparison with electronics-based radar,significant resolution improvement is observed.The results verify the superior imaging capability and practicability of the proposed radar and its great potential to outperform conventional technologies in target classification and recognition applications.展开更多
基金National Key Research and Development Program of China(2021YFB2800602)National Natural Science Foundation of China(62127805)+1 种基金Fundamental Research Funds for the Central Universities(2242022k60006)Open Research Fund of Key Laboratory of All Optical Network and Advanced Telecommunication Network,Ministry of Education,Beijing Jiaotong University(AON2024K02).
文摘Frequency-modulated continuous-wave(FMCW)light sources are essential components for coherent light detection and ranging(LiDAR),which is ubiquitously utilized in autonomous driving,industrial monitoring,and geological remote sensing.Traditional FMCW LiDAR systems often face challenges in achieving high frequencysweep linearity and large excursion,which are critical for accurate distance and velocity measurements.Here,we propose a self-injection locked laser with frequency-shifted feedback to generate ultra-linear and wideband FMCW light.A record-low relative frequency nonlinearity of 6.4×10^(-7)is achieved when the frequency excursion is 100 GHz and the repetition frequency is 1 kHz.In the LiDAR test,a range resolution of 1.6 mm and a velocity accuracy of 3 mm/s at 300 m distance are demonstrated,and those of 8.1 mm and 6 mm/s at 1 km distance are also obtained.The reported FMCW light source provides not only enhanced performance in coherent LiDAR,but also utilization potential in various high-precision measurement scenarios.
基金National Key Research and Development Program of China(2023YFB3207800)National Natural Science Foundation of China(61927804)。
文摘On-chip couplers are essential for coupling free-space electromagnetic waves into sub-wavelength semiconductor devices and enhancing light-matter interactions.However,the couplers used in existing single field-effect transistor(FET)detectors exhibit poor response over wide frequency ranges,making the detection of ultra-wideband weak signals highly challenging.In this work,we introduce a meta-array coupler for terahertz detectors based on field-effect transistors,which demonstrates exceptional coupling asymmetry beneath the gate.To optimize the meta-array structure for high gain across an ultra-wide frequency range,we propose a hybrid long short-term memory–multi-layer perceptron(LSTM-MLP)neural network for the detector’s on-chip coupler.This method enables accurate and rapid prediction of the enhanced spectra of meta-atoms,facilitating efficient conversion from structural parameters to resonance frequencies.Compared to traditional dipole couplers,the proposed metacoupler generates strong localized electric field enhancement through dipole resonance,achieving a mixing factor asymmetry up to 246 times higher near 660 GHz and an antenna factor enhancement of approximately 50 times.The meta-array coupled FET terahertz detector achieves ultra-wideband resonance enhancement from 350 to1000 GHz.This hardware architecture and hybrid LSTM-MLP neural network are expected to overcome the limitations of current FET-based detectors in coupling efficiency,bridging the performance gap toward ultra-sensitive detection applications.
基金supported by the National Major Scientific Research Instrument Development Project(No.61927804).
文摘Autonomous machines(AMs)are poised to possess human-like moral cognition,yet their morality is often pre-programmed for safety.This raises the question of whether the morality intended by programmers aligns with their actions during actual operation,a crucial consideration for a future society with both humans and AMs.Investigating this,we use a micro-robot swarm in a simulated fire scenario,with 180 participants,including 102 robot programmers,completing moral questionnaires and participating in virtual escape trials.These exercises mirror common societal moral dilemmas.Our comparative analysis reveals a“morality gap”between programming presets and real-time operation,primarily influenced by uncertainty about the future and heightened by external pressures,especially social punishment.This discrepancy suggests that operational morality can diverge from programmed intentions,underlining the need for careful AM design to foster a collaborative and efficient society.
基金supported by the China’s Space Origins Exploration Programthe National Key R&D Program of China (Grant No.2021YFA0718500)+10 种基金the support by the National Natural Science Foundation of China (Grant Nos.12373051,12273028,12173103,12261141691,and 12003009)the support by the Italian MUR (grant PRIN 2022 - 2022LWPEXW grant,“An X-ray view of compact objects in polarized light”,CUP C53D23001180006)the German Research Foundation (DFG) grant WE 1312/59-1 for financial supportUKRI Stephen Hawking fellowshipthe support by UKRI STFC (Grant No.ST/W507891/1)supported by the National Natural Science Foundation of China (Grant No.12333007)the International Partnership Program of Chinese Academy of Sciences (Grant No.113111KYSB20190020)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No.XDA15020100)supported by the National Natural Science Foundation of China (Grant Nos.12373041,and 12422306)the Bagui Scholars Program (XF)supported by STFC (Grant No.ST/Y001060/1)。
文摘In this paper we present the science potential of the enhanced X-ray Timing and Polarimetry(eXTP)mission,in its new configuration,for studies of strongly magnetized compact objects.We discuss the scientific potential of eXTP for quantum electrodynamic(QED)studies,especially leveraging the recent observations made with the NASA IXPE mission.Given eXTP’s unique combination of timing,spectroscopy,and polarimetry,we focus on the perspectives for physics and astrophysics studies of strongly magnetized compact objects,such as magnetars and accreting X-ray pulsars.Developed by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Sciences,the eXTP mission is expected to launch in early 2030.
基金supported by China’s Space Origins Exploration Programsupported by the National Natural Science Foundation of China (Grant No.12273028)+36 种基金support from ERC Consolidator (Grant No.865768) AEONSsupport from NWO grant ENW-XL OCENW.XL21.XL21.038the support of the CNESsupported by the National Natural Science Foundation of China (Grant No.12333007)the International Partnership Program of Chinese Academy of Sciences (Grant No.113111KYSB20190020)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDA15020100)supported by the China National Postdoctoral Program for Innovation Talents (Grant No.BX20240223)the China Postdoctoral Science Foundation Funded Project (Grant No.2024M761948)support from a Ramon y Cajal fellowship (Grant No.RYC2021-032718-I) financed by MCIN/AEI/10.13039/501100011033 and the European Union Next Generation EU/PRTRsupported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region (Grant No.2023D01E20)the National SKA Program of China (Grant No.2020SKA0120300)supported by the National Natural Science Foundation of China (Grant Nos.12033001,and 12473039)supported by Zhejiang Provincial Natural Science Foundation of China (Grant No.LQ24A030002)supported by the National Natural Science Foundation of China (Grant No.12003009)supported by the National SKA Program of China (Grant No.2020SKA0120200)the National Natural Science Foundation of China (Grant No.12041303)supported by the National Natural Science Foundation of China (Grant No.1227303)supported by the National SKA Program of China (Grant No.2020SKA0120300)the Beijing Natural Science Foundation (Grant No.1242018)the Max Planck Partner Group Program funded by the Max Planck Societysupported by JSPS KAKENHI (the Japan Society for the Promotion of Science,Grantsin-Aid for Scientific Research) (Grant Nos.23K19056,and 25K17403)supported by the National Natural Science Foundation of China (Grant No.12175109)support from FCT (Fundacao para a Ciência e a Tecnologia,I.P.,Portugal) (Grant Nos.UIDB/04564/2020,and 2022.06460.PTDC)supported from the program Unidad de Excelencia María de Maeztu CEX2020-001058-Mfrom the project PID2022-139427NB-I00 financed by the Spanish MCIN/AEI/10.13039/501100011033/FEDER,UE (FSE+)by the CRC-TR 211 “Strong-interaction matter under extreme conditions” -project Nr.315477589-TRR 211support from grant PID2021-124581OB-I0,PID2024-155316NB-I00,and 2021SGR00426supported by the National Natural Science Foundation of China (Grant No.12122513)supported in part by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant No.101020842)by the Deutsche Forschungsgemeinschaft (DFG,German Research Foundation)-Project-ID 279384907-SFB 1245support from the ERC Consolidator (Grant No.101002352) (LOVENEST)supported by the European Research Council (ERC) via the Consolidator Grant “MAGNESIA” (Grant No.817661)the Proof of Concept “Deep Space Pulse” (Grant No.101189496)the Catalan grant SGR2021-01269the Spanish grant ID2023-153099NA-I00the program Unidad de Excelencia Maria de Maeztu CEX2020-001058-Msupported by the Research Council of Finland (Grant No.354533).
文摘In this white paper,we present the potential of the enhanced X-ray timing and polarimetry(eXTP)mission to constrain the equation of state of dense matter in neutron stars,exploring regimes not directly accessible to terrestrial experiments.By observing a diverse population of neutron stars—including isolated objects,X-ray bursters,and accreting systems—eXTP’s unique combination of timing,spectroscopy,and polarimetry enables high-precision measurements of compactness,spin,surface temperature,polarimetric signals,and timing irregularity.These multifaceted observations,combined with advances in theoretical modeling,pave the way toward a comprehensive description of the properties and phases of dense matter from the crust to the core of neutron stars.Under development by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Sciences,the eXTP mission is planned to be launched in early 2030.
基金supported by National Natural Science Foundation of China(82271794 and 82302533)Shanghai Science and Technology Commission sailing project(22YF1404900).
文摘Background: Since infections can lead to adverse outcomes in autoimmune bullous diseases (AIBD), this study aimed to analyze infection characteristics in AIBD, predict infection risk factors and provide probable suggestions to infection prevention, which will spot a light on early discovery and prevention of infections in AIBD patients. Methods: This is a retrospective study of the medical records of inpatients diagnosed with AIBD at the Department of Infectious Diseases and Dermatology, Huashan Hospital from January 2017 to December 2021. We collected patients’ clinical manifestations and laboratory examination results. Risk factors for infections were evaluated using multivariate logistic regression. Results: A total of 263 AIBD patients were included in the study. The overall incidence of infection was 42.2% (111/263). Pemphigus had a higher infection rate (74/142, 52.1%) than bullous pemphigoid (37/121, 30.6%). Among the patients with infections, 49.5% (55/111) had bacterial infections, 13.5% (15/111) had fungal infections, 2.7% (3/111) had virus infections, and 34.2% (38/111) had mixed infections. Staphylococcus aureus and Candida were the most common pathogens in localized infections, while Cryptococcus and Candida were predominant in systemic infections. In the multivariate logistic model, pemphigus (odds ratio [OR] = 2.56, 95% confidence interval [CI] 1.41-4.63), hypoalbuminemia (OR = 3.78, 95% CI 1.68-8.50), and systemic glucocorticoid treatment (OR = 4.67, 95% CI 2.51-8.68) were independent risk factors for infection in AIBD patients. Bullous pemphigoid (OR = 3.99, 95% CI 1.03-15.45), high-dose (average > 24 mg/day) compared to low-dose (average ≤ 6 mg/day) and medium-dose (average 6-24 mg/day) systemic glucocorticoid treatment (OR = 19.31, 95% CI 3.32-112.28, and OR = 5.71, 95% CI 1.37-23.79) were associated with increased risk factors of systemic infection in AIBD patients with systemic glucocorticoid treatment. A methylprednisolone dose averaging 14 mg/day over the past three months had a 75.0% positive predictive value for infections in AIBD patients. Conclusions: The incidence of infection in AIBD patients is high, with a broad spectrum of pathogens and infection locations. AIBD patients undergoing systemic glucocorticoid treatment, especially those receiving high doses in the previous three months, should be cautious about infection.
基金973 Program(2014CB340003)National Natural Science Foundation of China(NSFC)(61307081,61321004,61420106003)
文摘We present a polarization-maintaining PANDA ring-core fiber(PM-PRCF) characterized by the combination of a ring-core structure with two stress-applying rods. This special fiber design separates the adjacent modes and avoids the cutoff of the higher-order modes, which is a common problem in elliptical core polarization-maintaining few-mode fibers. Using a high-contrast index ring and stress-induced birefringence, the PM-PRCF features support for 10 vector modes, with effective refractive index separations from their adjacent modes >10^(-4).Broadband performance is investigated subsequently over a wide wavelength range from 1500 to 1630 nm.The proposed fiber is targeted at applications in space-division multiplexing while eliminating the complex multiple-input multiple-output signal processing.
基金supported by the National Key R&D Program of China under grant no.2018YFA0701902the National Natural Science Foundation of China under grant no.61690192+1 种基金Zhejiang Lab under grant no.2020LC0AD01.P.G.acknowledges support from the EiPhi Graduate School under grant no.ANR-17-EURE-0004the French ISITE-BFC programs under grant no.ANR-15-IDEX-0003.
文摘Solitons are self-reinforcing localized wave packets that manifest in the major areas of nonlinear science,from optics to biology and Bose-Einstein condensates.Recently,optically driven dissipative solitons have attracted great attention for the implementation of the chip-scale frequency combs that are decisive for communications,spectroscopy,neural computing,and quantum information processing.In the current understanding,the generation of temporal solitons involves the chromatic dispersion as a key enabling physical effect,acting either globally or locally on the cavity dynamics in a decisive way.Here,we report on a novel class of solitons,both theoretically and experimentally,which builds up in spectrally confined optical cavities when dispersion is practically absent,both globally and locally.Precisely,the interplay between the Kerr nonlinearity and spectral filtering results in an infiinite hierarchy of eigenfunctions which,combined with optical gain,allow for the generation of stable dispersion-less dissipative solitons in a previously unexplored regime.When the filter order tends to infinity,we find an unexpected link between dissipative and conservative solitons,in the form of Nyquist-pulse-like solitons endowed with an ultra-flat spectrum.In contrast to the conventional dispersion-enabled nonlinear Schr?dinger solitons,these dispersion-less Nyquist solitons build on a fully confined spectrum and their energy scaling is not constrained by the pulse duration.Dispersion-less soliton molecules and their deterministic transitioning to single solitons are also evidenced.These findings broaden the fundamental scope of the dissipative soliton paradigm and open new avenues for generating soliton pulses and frequency combs endowed with unprecedented temporal and spectral features.
基金supported in part by the National Natural Science Foundation of China(NSFC)(Nos.61690191,61690192,61420106003,and 61621064)Chuanxin Funding,and Beijing Natural Science Foundation(No.4172027)
文摘A broadband photonic analog-to-digital converter（ADC） for X-band radar applications is proposed and experimentally demonstrated. An X-band signal with arbitrary waveform and a bandwidth up to 2 GHz can be synchronously sampled and processed due to the optical sampling structure. In the experiment, the chirp signal centered at 9 GHz with a bandwidth of 1.6 GHz is sampled and down-converted with a signal-to-noise ratio of 7.20 d B and an improved noise figure. Adopting the photonic ADC in the radar receiver and the above signal as the transmitted radar signal, an X-band inverse synthetic aperture radar system is set up, and the range and cross-range resolutions of 9.4 and 8.3 cm are obtained, respectively.
基金National Natural Science Foundation of China(NSFC)(61420106003,61690191,61690192)Natural Science Foundation of Beijing Municipality(4172029)
文摘Microcomb generation with simultaneous χ2 and χ3 nonlinearities brings new possibilities for ultrabroadband and potentially self-referenced integrated comb sources. However, the evolution of the intracavity field involving multiple nonlinear processes shows complex dynamics that are still poorly understood. Here, we report on strong soliton regulation induced by fundamental–second-harmonic(FD-SH) mode coupling. The formation of solitons from chaos is extensively investigated based on coupled Lugiato–Lefever equations. The soliton generation shows more deterministic behaviors in the presence of FD-SH mode interaction, which is in sharp contrast with the usual cases where the soliton number and relative locations are stochastic. Deterministic single soliton transition, soliton binding, and prohibition are observed, depending on the phase-matching condition and coupling coefficient between the fundamental and second-harmonic waves. Our finding provides important new insights into the soliton dynamics in microcavities with simultaneous χ~2and χ~3nonlinearities and can be immediate guidance for broadband soliton comb generation with such platforms.
基金supported by the National Key Research and Development Program of China (No. 2020YFF0304900)the National Major Scientific Research Instrument Development Project of China (No. 61927804)。
文摘With the increase in large-scale incidents in real life, crowd evacuation plays a pivotal role in ensuring the safety of human crowds during emergency situations. The behavior patterns of crowds are well rendered by existing crowd dynamics models. However, most related studies ignore the information perception of pedestrians.To overcome this issue, we develop a visual information based social force model to simulate the interpretable evacuation process from the perspective of visual perception. Numerical experiments indicate that the evacuation efficiency and decision-making ability promote rapidly within a small range with the increase in unbalanced prior knowledge. The propagation of acceleration behavior caused by emergencies is asymmetric due to the anisotropy of visual information. Therefore, this model effectively characterizes the effect of visual information on crowd evacuation and provides new insights into the information perception of individuals in complex scenarios.
基金the National Key Research and Development Program of China(No.2019YFB2203301)the National Natural Science Foundation of China(No.61690191/2).
文摘A photonic approach to concurrently measure the angle-of-arrival(AOA) and the chirp rate of a linear frequency modulated(LFM) signal is proposed and experimentally demonstrated. The measurement is achieved by estimating the differential frequency of a two-tone signal output by a dual-parallel Mach–Zehnder modulator and an additional asymmetry Mach–Zehnder interferometer. Experiments show that the AOA and the chirp rate are measured simultaneously, with an AOA measurement error of ?0.1° at an signal-to-noise ratio(SNR) of 9.6 d B.When the SNR is-10.4 d B, the AOA error is ?1.3°, and the chirp rate, measured as 210.2 ? 1.5 Hz∕ps, has a standard deviation of 0.7%. The measured chirp rate agrees well with the real LFM signal.
文摘This paper presents an introduction to the researches in microwave photonics based packages and its application, a 973 project （No. 2012CB315600）, which focuses on addressing new requirements for millimeter wave （MMW） system to work with higher frequency, wider bandwidth, larger dynamic range and longer distance of signal distribution. Its key scientific problems, main research contents and objectives are briefed, and some latest achievements by the project team, including generation of linear frequency modulation wave （LFMW）, tunable optoelectronic oscillator （OEO） with lower phase noise, reconfigurable filter with higher Q value, time delay line with wider frequency range, down conversion with gain, and local oscillator （LO） transmission with stable phase, are introduced briefly.
基金supported by a grant from Doctoral Foundation of Ministry of Education of China(Grant No.20070010014)the Program for a New Century of Excellent University Talents,Ministry of Education of China(Grant No.NCET-07-0056).
文摘Drug safety management is an important issue in China drug management system and attracts great attentions from the whole society.In order to reduce drug incident,this study discusses some important elements associated with China drug safety management system and analyzes the data collected by questionnaires.Besides,a methodology for rating the important elements is described and applied.The non-structural fuzzy group decision method not only considers the insufficient precise information but also combines the opinions of different kinds of respondents in China’s four municipalities.The results indicate that the sample systems are the most important in these important elements,and the order of importance is sampling systems,licensing systems,traceability systems,transaction models,pharmacovigilance and emergence management.This study not only points out the important ranking of the pivotal elements in China drug safety management but also gives some specific proposals about how to enhance drug safety management in China.
基金supported by the National Natural Science Foundation of China(Grant No.70502006)the Program for a New Century of Excellent University Talents,Ministry of Education of the People’s Republic of China(No.NCET-07-0056).
文摘It is a pioneering work to use a Markov chain model to study the pedestrian escape route without visibility.In this paper,based on the Markov chain probability transition matrix,the algorithms with random numbers and the spatial-grid,an escape route in a limited invisible space is obtained.Six pace states(standing,crawling,walking,leaping,jogging,and running)are applied to describe the characteristics of pedestrian behaviors.Besides,eight main direction changes are used to describe the transition characteristic of a pedestrian.At the same time,this paper analyzes the escape route from two views,i.e.,pedestrian pace states and directions.The research results show that the Markov chain model is more realistic as a means of studying pedestrian escape routes.
基金National Natural Science Foundation of China(61690191,62101536)。
文摘Three-dimensional(3D)imaging radar is an advanced sensor applied in space surveillance and target recognition for supplying 3D geometric features and supporting visualization.However,high 3D resolution requires both broadband operation and a large 2D aperture,which are difficult and complex for conventional radars.This paper presents a photonics-enabled distributed multiple-input and multiple-output(MIMO)radar with a centralized architecture.By use of photonic multi-dimensional multiplexing,multi-channel signal generation and reception are implemented on a shared reference signal in a central office,enabling a highly coherent network with a simple structure.Additionally,a sparse array and a synthetic aperture are combined to efficiently reduce the required transceivers,further weakening the dilemma between system complexity and angular resolution.A 4×4 MIMO radar is established and evaluated in field tests.A high-resolution 3D image of a non-cooperative aircraft is obtained,in which rich details are displayed.From a comparison with electronics-based radar,significant resolution improvement is observed.The results verify the superior imaging capability and practicability of the proposed radar and its great potential to outperform conventional technologies in target classification and recognition applications.
