In this paper, we propose an optical quantization scheme for all-optical analog-to-digital conversion that facilitates photonics integration. A segment of 10-m photonic crystal fiber with a high nonlinear coefficient ...In this paper, we propose an optical quantization scheme for all-optical analog-to-digital conversion that facilitates photonics integration. A segment of 10-m photonic crystal fiber with a high nonlinear coefficient of 62.8 W-1/kin is utilized to realize large scale soliton self-frequency shift relevant to the power of the sampled optical signal. Furthermore, a 100-m dispersion-increasing fiber is used as the spectral compression module for further resolution enhancement. Simulation results show that 317-nm maximum wavelength shift is realized with 1550-nm initial wavelength and 6-bit quantization resolution is obtained with a subsequent spectral compression process.展开更多
In this paper, we optimize a proposed all-optical quantization scheme based on soliton self-frequency shift(SSFS)and pre-chirp spectral compression techniques. A 10m-long high-nonlinear photonic crystal fiber(PCF) is ...In this paper, we optimize a proposed all-optical quantization scheme based on soliton self-frequency shift(SSFS)and pre-chirp spectral compression techniques. A 10m-long high-nonlinear photonic crystal fiber(PCF) is used as an SSFS medium relevant to the power of the sampled optical pulses. Furthermore, a 10m-long dispersion flattened hybrid cladding hexagonal-octagonal PCF(6/8-PCF) is utilized as a spectral compression medium to further enhance the resolution. Simulation results show that 6-bit quantization resolution is still obtained when a 100m-long dispersion-increasing fiber(DIF)is replaced by a 6/8-PCF in spectral compression module.展开更多
Raman soliton self-frequency shifted to mid-infrared band（λ 〉 2 μm） has been achieved in an air-silica microstructure fiber（MF）. The MF used in our experiment has an elliptical core with diameters of 1.08 and 2...Raman soliton self-frequency shifted to mid-infrared band（λ 〉 2 μm） has been achieved in an air-silica microstructure fiber（MF）. The MF used in our experiment has an elliptical core with diameters of 1.08 and 2.48 μm for fast and slow axis. Numerical simulation shows that each fundamental orthogonal polarization mode has two wide-spaced λZDW and theλZDW pairs located at 701/2110 nm and 755/2498 nm along the fast and slow axis, respectively. Using 810-nm Ti：sapphire femtosecond laser as pump, when the output power varies from 0.3 to 0.5 W, the furthest red-shift Raman solitons in both fast and slow axis shift from near-infrared band to mid-infrared band, reaching as far as 2030 and 2261 nm. Also, midinfrared Raman solitons can always be generated for pump wavelength longer than 790 nm if output pump power reaches0.5 W. Specifically, with pump power at 0.5 W, the mid-infrared soliton in slow axis shifts from 2001 to 2261 nm when the pump changes from 790 nm to 810 nm. This means only a 20 nm change of pump results in 260 nm tunability of a mid-infrared soliton.展开更多
By adjusting the polarisation state of the pump at 805 nm parallel to slow （x） and fast （y） axes of the highly birefringent photonic crystal fibre with zero dispersion wavelengths 790 nm and 750 nm, this paper dem...By adjusting the polarisation state of the pump at 805 nm parallel to slow （x） and fast （y） axes of the highly birefringent photonic crystal fibre with zero dispersion wavelengths 790 nm and 750 nm, this paper demonstrates the efficient polarisation-sensitive four wave mixing involved in pump, anti-Stokes and Stokes signals and soliton self- frequency shift effects induced by the phase-matching between red-shifted solitons and blue-shifted dispersive waves. If the reduction of coupling efficiency to the circular pump laser mode or other circular fibres due to asymmetry of the core is neglected, more than 98% of the total input power is kept in a single linear polarisation. Controlled dispersion characteristic of the doublet of fundamental guided-modes results in achieving light field strongly confined in principal axes of photonic crystal fibre, and enhancing the corresponding nonlinear-optical process through the remarkable nonlinear birefringence.展开更多
Northeast China(NEC),a critical agricultural and ecological zone,has experienced intensified hydrological variability under global warming,with cascading impacts on food security and ecosystem resilience.This study ut...Northeast China(NEC),a critical agricultural and ecological zone,has experienced intensified hydrological variability under global warming,with cascading impacts on food security and ecosystem resilience.This study utilized observational data and two new generation reanalysis products(i.e.,the fifth major global reanalysis produced by ECMWF(ERA5)and the Japanese Reanalysis for Three Quarters of a Century(JRA-3Q))to investigate the shift changes in precipitation in NEC around 2000 and associated water vapor transport.The analysis identified a pivotal interdecadal shift in 1998/99,transitioning from moderate increases(17.5 mm/10 yr during 1980-1998)to accelerated but more variable precipitation growth(85.4 mm/10 yr post-1999).While the mean precipitation during the post-shift period decreased,enhanced anticyclonic circulation amplified moisture divergence over continental NEC,redirecting vapor flux toward coastal regions.Crucially,trajectory analysis demonstrated regime-dependent moisture sourcing:midlatitude westerlies dominated during wet extremes(44% of trajectories in 1998),whereas East Asian monsoon flows prevailed in drought years(36% of trajectories in 2007).The post-1998 period exhibited increased reliance on localized recycling(45%of mid-tropospheric trajectories),reflecting weakened monsoonal inflow.These findings highlight NEC’s growing vulnerability to competing moisture pathways and atmospheric blocking-a dual mechanism that explains rising extremes despite declining mean precipitation.By reconciling dataset discrepancies(ERA5 vs.JRA-3Q trends)and elucidating circulation-precipitation linkages,this work provides actionable insights for climate-resilient agriculture in NEC’s water-stressed ecosystems.展开更多
The current dialogue system can be sensitive to the emotions in the user's words,generating an empathetic response to help calm the user's emotions.But in some cases,eliciting empathetic responses may not adeq...The current dialogue system can be sensitive to the emotions in the user's words,generating an empathetic response to help calm the user's emotions.But in some cases,eliciting empathetic responses may not adequately mitigate the adverse effects that the current conversation topic is having on users.The dialogue system will continue the conversation with the user under this uncomfortable topic,which will lead to a worse chat situation or even an impasse.To solve this problem,a dialogue system that can change the topic autonomously according to the user's emotions is proposed in this paper.Specifically,the dialogue system first collects the emotional semantic information of the users and then detects it according to the emotion classification module.Once the detection results show that the user is in a bad mood,the topic change module selects a new topic from the context to shift to and generates a response.This not only helps to calm the user's mood but also move the conversation to a new area,steering the user away from the uncomfortable topic.The experimental results show that the proposed method incurs less cost in terms of content quality,but improves the emotional perception ability.Additionally,it endows the dialogue system with the ability to change the topic,and improves the user's dialogue experience.展开更多
The transition energies of the 1s^(2)2s^(2)S_(1/2)→1s^(2)2p^(2)p_(1/2,3/2)transitions in Li-like Th87+ions were calculated by combining the multi-configuration Dirac-Hartree-Fock(MCDHF)method with the model-quantum e...The transition energies of the 1s^(2)2s^(2)S_(1/2)→1s^(2)2p^(2)p_(1/2,3/2)transitions in Li-like Th87+ions were calculated by combining the multi-configuration Dirac-Hartree-Fock(MCDHF)method with the model-quantum electrodynamics(modelQED)approach.The effects of electron correlation,Breit interaction,and QED effects were analyzed in detail.The isotope shifts,including the mass shifts and field shifts,due to the 2s2S_(1/2)→2p^(2)P_(1/2,3/2)transitions were then calculated using two different methods,namely,the MCDHF method and the finite-field method.The results show that these two methods are in excellent agreement.展开更多
With the continuous improvement of the medical industry’s requirements for the professional capabilities of nursing talents,traditional nursing teaching models can hardly meet the needs of complex nursing work in neu...With the continuous improvement of the medical industry’s requirements for the professional capabilities of nursing talents,traditional nursing teaching models can hardly meet the needs of complex nursing work in neurology.This paper focuses on nursing education for neurology nursing students and explores the construction of the“one-on-one”teaching model,aiming to achieve a paradigm shift in nursing education.By analyzing the current status of neurology nursing education,this paper identifies the problems in traditional teaching models.Combining the advantages of the“one-on-one”teaching model,it elaborates on the construction path of this model from aspects such as the selection and training of teaching instructors,the design of teaching content,the innovation of teaching methods,and the improvement of the teaching evaluation system.The research shows that the“one-on-one”teaching model can significantly enhance nursing students’mastery of professional knowledge,clinical operation skills,communication skills,and emergency response capabilities,as well as strengthen their professional identity and sense of responsibility.It provides an effective way to cultivate high-quality nursing talents who can meet the needs of neurology nursing work and promotes the innovative development of nursing education.展开更多
National Fire codes,mandated by government authorities to tackle technical challenges in fire prevention and control,establish fundamental standards for construction practices.International collaboration in fire prote...National Fire codes,mandated by government authorities to tackle technical challenges in fire prevention and control,establish fundamental standards for construction practices.International collaboration in fire protection technologies has opened avenues for China to access a wealth of documents and codes,which are crucial in crafting regulations and developing a robust,scientific framework for fire code formulation.However,the translation of these codes into Chinese has been inadequate,thereby diminishing the benefits of technological exchange and collaborative learning.This underscores the necessity for comprehensive research into code translation,striving for higher-quality translations guided by established translation theories.In this study,we translated the initial segment of the NFPA 1 Fire Code into Chinese and examined both the source text and target text through the lens of Translation Shift Theory,a concept introduced by Catford.The conclusion culminated in identifying four key shifts across various linguistic levels:lexis,sentences,and groups,to ensure an accurate and precise translation of fire codes.This study offers a through and lucid explanation of how the translator integrates Catford’s theories to solve technical challenges in NFPA 1 Fire Code translation,and establish essential standards for construction translation practices.展开更多
Highly accurate international height reference frames with long-term stability,global consistency,and homogeneity are crucial for monitoring sea level variations,understanding climate change,managing disasters,and sup...Highly accurate international height reference frames with long-term stability,global consistency,and homogeneity are crucial for monitoring sea level variations,understanding climate change,managing disasters,and supporting other applications that benefit scientific research and societal well-being.Currently,there are over 100 local height reference systems worldwide.Unifying these systems is a pivotal step toward constructing international height reference frames.The method introduced in this study-the gravity frequency shift via Satellite Frequency Signal Transfer(SFST)-represents a groundbreaking relativistic geodetic approach,demonstrating its potential to surpass the constraints of conventional techniques.The advent of high-precision optical atomic clocks(OAC)with an accuracy level of 1×10^(-18) has facilitated this method's implementation.The International Association of Geodesy(IAG)has established the International Height Reference System(IHRS)and its practical realization,the International Height Reference Frame(IHRF).Our study focuses on two neighbouring height systems:the China Height System(CHS)and the Nepal Height System(NHS),separated by the Himalayas and the Xizang plateau.We aim to unify these two systems by determining the geopotential and orthometric height differences between their respective height datum stations:the Qingdao Height Datum Station(QHDS)and the Madar Height Datum Station(MHDS)using a simulation experiment with the method mentioned above.Using an OAC with an accuracy of 1×10^(-18),we identified a geopotential difference of-8.348±0.464 m^(2)s^(-2) and an orthometric height difference of 0.786±0.047 m between QHDS and MHDS.These results suggest that the introduced method could unify any two height systems with fewcentimeter-level precision,emphasizing its significance in contributing to the construction of the IHRS/IHRF with today's required precision.In summary,the SFST technique is a novel geodetic method that offers an alternative for height system unification,delivering centimeter-level precision,surpassing traditional methods,and supporting the development of the IHRF.展开更多
The phenomenon of verbal-to-nominal shift(hereafter referred to as“V-N shift”)exists in both English and Chinese.It reflects both the universal conceptual metonymic thinking and the principle of linguistic economy.F...The phenomenon of verbal-to-nominal shift(hereafter referred to as“V-N shift”)exists in both English and Chinese.It reflects both the universal conceptual metonymic thinking and the principle of linguistic economy.Focusing on conceptual metonymy theory and combined with the Event Idealized Cognitive Model(ICM),this paper systematically compares the V-N shift phenomenon in English and Chinese.The study shows that English and Chinese V-N shifts share the core cognitive mechanism of“conceptual proximity within the Event ICM”,while significant differences exist in type distribution and usage frequency.This analysis not only helps deepen the understanding of the cognitive logic behind English and Chinese V-N shifts but also provides a new perspective for the study of word-class conversion and the relationship between language and thinking.展开更多
The degradation and nonlinear interactions of a two-breather solution of the Mel’nikov equation are analyzed.By modulating the phase shift and limit method,we prove that in different regions near the non-singular bou...The degradation and nonlinear interactions of a two-breather solution of the Mel’nikov equation are analyzed.By modulating the phase shift and limit method,we prove that in different regions near the non-singular boundaries,there are four kinds of solutions with repulsive interaction or attractive interaction in addition to the two-breather solution.They are the interaction solution between soliton and breather,the two-soliton solution,and the two-breather solution with small amplitude,which all exhibit repulsive interactions;and the two-breather solution with small amplitude,which exhibits attractive interaction.Interestingly,a new breather acts as a messenger to transfer energy during the interaction between two breather solutions with small amplitude.展开更多
Anthropogenic climate change is altering species distributions globally.While species distributions are expected to shift to higher latitudes and elevations under global warming,empirical evidence on distribution shif...Anthropogenic climate change is altering species distributions globally.While species distributions are expected to shift to higher latitudes and elevations under global warming,empirical evidence on distribution shifts is mixed,and factors mediating the direction and magnitude of range shifts remain unclear.Using a dataset of 132new provincial records for 96 resident bird species from 2000 to 2023,we measured geographic distance,latitudinal shift,and temperature shift from each new record to the historical range for each species to test for poleward shifts.We assessed taxonomic variation in the magnitude of range shifts and used phylogenetic generalized linear mixed models to quantify relationships between species traits and the extent of range shifts.Our results revealed that new records occurred at a mean geographic distance of 420 km from historical ranges,with mean latitudinal shifts of+1.68°(poleward)and temperature shifts of-1.33℃(toward colder climates).The magnitude of geographic range shifts was strongly constrained by phylogenetic relatedness.Habitat breadth,habitat openness,and centroid latitude of historical ranges emerged as significant predictors of range shifts.Our results suggest that resident bird species'geographic ranges in China are shifting poleward,but the magnitude of these shifts is non-random across lineages.Species with broader habitat preferences and those from warmer climates are more likely to shift farther from their historical ranges and toward higher latitudes.This study emphasizes taxonomic variation in species range shifts and highlights the need for species-and site-specific conservation strategies under global warming.展开更多
Standard perturbation theory is employed to calculate the mass shifts of the 2^(1)S_(0)-^(3)S_(1)and 2^(3)S_(1)-2^(3)P_(J)transitions for^(4,6,8)He.High-precision results are obtained for the mass shifts in the isotop...Standard perturbation theory is employed to calculate the mass shifts of the 2^(1)S_(0)-^(3)S_(1)and 2^(3)S_(1)-2^(3)P_(J)transitions for^(4,6,8)He.High-precision results are obtained for the mass shifts in the isotope pairs 6He-4He and 8He-4He,with uncertainties below 1 part per million(ppm).Our analysis provides a complete set of isotope-shift results and systematically examines their sensitivity to nuclear charge-radius differences.Once experimental measurements reach a precision comparable to that of the calculated mass shifts,the squared differences of nuclear charge radii can be determined with an accuracy of approximately 0.4%-0.6%,representing an order-of-magnitude improvement over current values.展开更多
Gait recognition,a promising biometric technology,relies on analyzing individuals' walking patterns and offers a non-intrusive and convenient approach to identity verification.However,gait recognition accuracy is ...Gait recognition,a promising biometric technology,relies on analyzing individuals' walking patterns and offers a non-intrusive and convenient approach to identity verification.However,gait recognition accuracy is often compromised by external factors such as changes in viewpoint and attire,which present substantial challenges in practical applications.To enhance gait recognition performance under diverse viewpoints and complex conditions,a global-local part-shift network is proposed in this paper.This framework integrates two novel modules:the part-shift feature extractor and the dynamic feature aggregator.The part-shift feature extractor strategically shifts body parts to capture the intrinsic relationships between non-adjacent regions,enriching the recognition process with both global and local spatial features.The dynamic feature aggregator addresses long-range dependency issues by incorporating multi-range temporal modeling,effectively aggregating information across parts and time steps to achieve a more robust recognition outcome.Comprehensive experiments on the CASIA-B dataset demonstrate that the proposed global-local part-shift network delivers superior performance compared with state-of-the-art methods,highlighting its potential for practical deployment.展开更多
According to the 2024 China Marine Economy Statistical Bulletin(hereinafter“the Bulletin”),China’s marine economy surpassed the 10 trillion yuan(US$1.38 trillion)mark for the first time in 2024,0.9 percentage point...According to the 2024 China Marine Economy Statistical Bulletin(hereinafter“the Bulletin”),China’s marine economy surpassed the 10 trillion yuan(US$1.38 trillion)mark for the first time in 2024,0.9 percentage points higher than the growth rate of the national GDP.展开更多
We investigate theoretically the effects of chirped laser pulses on high-order harmonic generation(HHG)from solids.We find that the harmonic spectra display redshifts for the driving laser pulses with negative chirp a...We investigate theoretically the effects of chirped laser pulses on high-order harmonic generation(HHG)from solids.We find that the harmonic spectra display redshifts for the driving laser pulses with negative chirp and blueshifts for those with positive chirp,which is due to the change in the instantaneous frequency of the driving laser for different chirped pulses.The analysis of crystal-momentum-resolved(k-resolved)HHG reveals that the frequency shifts are equal for the harmonics generated by different crystal momentum channels.The frequency shifts in the cutoff region are larger than those in the plateau region.With the increase of the absolute value of the chirp parameters,the frequency shifts of HHG become more significant,leading to the shifts from odd-to even-order harmonics.We also demonstrate that the frequency shifts of harmonic spectra are related to the duration of the chirped laser field,but are insensitive to the laser intensity and dephasing time.展开更多
An enhanced understanding of the history of the western Qinling-Dabie orogen is pivotal in reconstructing geological processes of the east Asian mainland.However,less attention has been paid to its early-stage uplift-...An enhanced understanding of the history of the western Qinling-Dabie orogen is pivotal in reconstructing geological processes of the east Asian mainland.However,less attention has been paid to its early-stage uplift-erosion history after closure of surrounding oceanic basins at the mid-Paleozoic.In this study,we undertook a comprehensive study including paleocurrent reconstruction,sandstone petrology,and detrital zircon U-Pb dating on Late Carboniferous to Early Permian successions in the southern Ordos neighboring the northern Qinling-Dabie.New provenance data reveal a significant provenance shift at the Carboniferous-Permian transition.The older Benxi Formation was sourced southerly from the North Qinling Terrane that provided detritus mostly of Neoproterozoic and Early Paleozoic ages.In contrast,Early Permian samples yield age relation dominated by Neoarchean,Paleoproterozoic,Early Paleozoic,and Late Paleozoic age populations,with a significant gap of ca.1600-550 Ma,implying a sediment derivation from the Inner Mongolia Continental Arc.This shift is further verified by paleocurrent transition from south to north then.We suggest that the North Qinling Terrane experienced a significant uplift history from ca.500 Ma and remained as a highland until end-Carboniferous.From Early Permian,the North Qinling Terrane was submerged,covered by widespread deltaic sedimentation there.Northerly source from the Inner Mongolia Continental Arc began to be accumulated in the northern flank of the North Qinling Terrane,before termination approximately along the southern North Qinling Terrane,where shallow-water carbonate shelf sedimentation sustained from Devonian to Triassic.This new finding indicates that uplift of the North Qinling Terrane lasted about 150 Ma after the Proto-Tethys Ocean closure.展开更多
The aggressive nature and high mortality rate of lung cancer underscore the imperative need for early diagnosis of the disease.Thus,aminopeptidase N(APN),a potential biomarker for lung cancer,should be thoroughly inve...The aggressive nature and high mortality rate of lung cancer underscore the imperative need for early diagnosis of the disease.Thus,aminopeptidase N(APN),a potential biomarker for lung cancer,should be thoroughly investigated in this context.This report describes the development of HA-apn,a novel near-infrared fluorescent probe,specifically engineered for the sensitive detection of endogenous APN.Characterized by its high selectivity,straightforward molecular architecture,and suitable optical properties,including a long-wavelength emission at 835 nm and a large Stokes shift of 285 nm,HA-apn had high efficacy in identifying overexpressed APN in tumor cells,which shows its potential in pinpointing malignancies.To further validate its applicability and effectiveness in facilitating the direct and enhanced visualization of pulmonary alterations,an in situ lung cancer mouse model was employed.Notably,HAapn was applied for in vivo imaging of APN activity in the lung cancer mouse model receiving the probe through aerosol inhalation,and rapid and precise diagnostic results were achieved within 30min postadministration.Overall,HA-apn can be applied as an effective,non-intrusive tool for the rapid and accurate detection of pulmonary conditions.展开更多
Against the backdrop of climate change,the activity of tropical cyclones(TCs)has captured widespread attention.Observational datasets indicate a declining trend in the genesis longitude of western North Pacific(WNP)TC...Against the backdrop of climate change,the activity of tropical cyclones(TCs)has captured widespread attention.Observational datasets indicate a declining trend in the genesis longitude of western North Pacific(WNP)TCs.This study investigates the zonal changes of WNP TCs with CMIP6-HighResMIP models.These models capture the genesis density of WNP TCs fairly well.The results reveal a westward shift in TC genesis longitude.This trend is associated with the significant reduction in the TC frequency over the southeastern WNP.The study also discusses changes in large-scale circulation patterns and the impact of the strengthening Pacific Walker circulation.展开更多
基金Project supported by the National Basic Research Program of China(Grant Nos.2010CB327605 and 2010CB328304)the National High-Technology Research and Development Program of China(Grant No.2013AA031501)+7 种基金the National Natural Science Foundation of China(Grant No.61307109)the Research Foundation from Ministry of Education of China(Grant No.109015)the Program for New Century Excellent Talents in University of Ministry of Education of China(Grant No.NECT-11-0596)the Beijing Nova Program,China(Grant No.2011066)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120005120021)the Fundamental Research Funds for the Central Universities of Ministry of Education of China(Grant No.2013RC1202)the China Postdoctoral Science Foundation(Grant No.2012M511826)the Postdoctoral Science Foundation of Guangdong Province,China(Grant No.244331)
文摘In this paper, we propose an optical quantization scheme for all-optical analog-to-digital conversion that facilitates photonics integration. A segment of 10-m photonic crystal fiber with a high nonlinear coefficient of 62.8 W-1/kin is utilized to realize large scale soliton self-frequency shift relevant to the power of the sampled optical signal. Furthermore, a 100-m dispersion-increasing fiber is used as the spectral compression module for further resolution enhancement. Simulation results show that 317-nm maximum wavelength shift is realized with 1550-nm initial wavelength and 6-bit quantization resolution is obtained with a subsequent spectral compression process.
文摘In this paper, we optimize a proposed all-optical quantization scheme based on soliton self-frequency shift(SSFS)and pre-chirp spectral compression techniques. A 10m-long high-nonlinear photonic crystal fiber(PCF) is used as an SSFS medium relevant to the power of the sampled optical pulses. Furthermore, a 10m-long dispersion flattened hybrid cladding hexagonal-octagonal PCF(6/8-PCF) is utilized as a spectral compression medium to further enhance the resolution. Simulation results show that 6-bit quantization resolution is still obtained when a 100m-long dispersion-increasing fiber(DIF)is replaced by a 6/8-PCF in spectral compression module.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61405172,61405173,and 61275093)the Natural Science Foundation of Hebei Province,China(Grant No.F2014203194)+1 种基金the College Science Research Program of Hebei Province,China(Grant No.QN20131044)the Program of Independent Research for the Young Teachers of Yanshan University of China(Grant No.13LGB017)
文摘Raman soliton self-frequency shifted to mid-infrared band（λ 〉 2 μm） has been achieved in an air-silica microstructure fiber（MF）. The MF used in our experiment has an elliptical core with diameters of 1.08 and 2.48 μm for fast and slow axis. Numerical simulation shows that each fundamental orthogonal polarization mode has two wide-spaced λZDW and theλZDW pairs located at 701/2110 nm and 755/2498 nm along the fast and slow axis, respectively. Using 810-nm Ti：sapphire femtosecond laser as pump, when the output power varies from 0.3 to 0.5 W, the furthest red-shift Raman solitons in both fast and slow axis shift from near-infrared band to mid-infrared band, reaching as far as 2030 and 2261 nm. Also, midinfrared Raman solitons can always be generated for pump wavelength longer than 790 nm if output pump power reaches0.5 W. Specifically, with pump power at 0.5 W, the mid-infrared soliton in slow axis shifts from 2001 to 2261 nm when the pump changes from 790 nm to 810 nm. This means only a 20 nm change of pump results in 260 nm tunability of a mid-infrared soliton.
基金partly supported by the National Basic Research Program (Grant Nos. 2010CB327605 and 2010CB328300)Nationa lHigh-Technology Research and Development Program of China (Grant Nos. 2007AA03Z447 and 2009AA01Z220)+2 种基金the National Natural Science Foundation of China (Grant No. 60807022)the Key Grant of Ministry of Education of China (Grant No. 109015)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20070013001)
文摘By adjusting the polarisation state of the pump at 805 nm parallel to slow （x） and fast （y） axes of the highly birefringent photonic crystal fibre with zero dispersion wavelengths 790 nm and 750 nm, this paper demonstrates the efficient polarisation-sensitive four wave mixing involved in pump, anti-Stokes and Stokes signals and soliton self- frequency shift effects induced by the phase-matching between red-shifted solitons and blue-shifted dispersive waves. If the reduction of coupling efficiency to the circular pump laser mode or other circular fibres due to asymmetry of the core is neglected, more than 98% of the total input power is kept in a single linear polarisation. Controlled dispersion characteristic of the doublet of fundamental guided-modes results in achieving light field strongly confined in principal axes of photonic crystal fibre, and enhancing the corresponding nonlinear-optical process through the remarkable nonlinear birefringence.
基金supported by the National Natural Science Foundation of China[grant numbers 42275185 and 42205032]the Fundamental Research Funds for the Central Universities[grant number B250201118]。
文摘Northeast China(NEC),a critical agricultural and ecological zone,has experienced intensified hydrological variability under global warming,with cascading impacts on food security and ecosystem resilience.This study utilized observational data and two new generation reanalysis products(i.e.,the fifth major global reanalysis produced by ECMWF(ERA5)and the Japanese Reanalysis for Three Quarters of a Century(JRA-3Q))to investigate the shift changes in precipitation in NEC around 2000 and associated water vapor transport.The analysis identified a pivotal interdecadal shift in 1998/99,transitioning from moderate increases(17.5 mm/10 yr during 1980-1998)to accelerated but more variable precipitation growth(85.4 mm/10 yr post-1999).While the mean precipitation during the post-shift period decreased,enhanced anticyclonic circulation amplified moisture divergence over continental NEC,redirecting vapor flux toward coastal regions.Crucially,trajectory analysis demonstrated regime-dependent moisture sourcing:midlatitude westerlies dominated during wet extremes(44% of trajectories in 1998),whereas East Asian monsoon flows prevailed in drought years(36% of trajectories in 2007).The post-1998 period exhibited increased reliance on localized recycling(45%of mid-tropospheric trajectories),reflecting weakened monsoonal inflow.These findings highlight NEC’s growing vulnerability to competing moisture pathways and atmospheric blocking-a dual mechanism that explains rising extremes despite declining mean precipitation.By reconciling dataset discrepancies(ERA5 vs.JRA-3Q trends)and elucidating circulation-precipitation linkages,this work provides actionable insights for climate-resilient agriculture in NEC’s water-stressed ecosystems.
基金Sponsored by Natural Science Foundation of Heilongjiang Provincial(Grant No.LH2023F033)Science and Technology Innovation Talent Project of Harbin(Grant No.2022CXRCCG006).
文摘The current dialogue system can be sensitive to the emotions in the user's words,generating an empathetic response to help calm the user's emotions.But in some cases,eliciting empathetic responses may not adequately mitigate the adverse effects that the current conversation topic is having on users.The dialogue system will continue the conversation with the user under this uncomfortable topic,which will lead to a worse chat situation or even an impasse.To solve this problem,a dialogue system that can change the topic autonomously according to the user's emotions is proposed in this paper.Specifically,the dialogue system first collects the emotional semantic information of the users and then detects it according to the emotion classification module.Once the detection results show that the user is in a bad mood,the topic change module selects a new topic from the context to shift to and generates a response.This not only helps to calm the user's mood but also move the conversation to a new area,steering the user away from the uncomfortable topic.The experimental results show that the proposed method incurs less cost in terms of content quality,but improves the emotional perception ability.Additionally,it endows the dialogue system with the ability to change the topic,and improves the user's dialogue experience.
基金Project supported by the National Key Research and Development Program of China(Grant No.2022YFA1602500)the National Natural Science Foundation of China(Grant Nos.1236040286,12474250,12174316,12464036,and12404306)+1 种基金the Young Teachers Scientific Research Ability Promotion Plan of Northwest Normal University(Grant No.NWNU-LKQN2020-10)the Funds for Innovative Fundamental Research Group Project of Gansu Province(Grant No.20JR5RA541)。
文摘The transition energies of the 1s^(2)2s^(2)S_(1/2)→1s^(2)2p^(2)p_(1/2,3/2)transitions in Li-like Th87+ions were calculated by combining the multi-configuration Dirac-Hartree-Fock(MCDHF)method with the model-quantum electrodynamics(modelQED)approach.The effects of electron correlation,Breit interaction,and QED effects were analyzed in detail.The isotope shifts,including the mass shifts and field shifts,due to the 2s2S_(1/2)→2p^(2)P_(1/2,3/2)transitions were then calculated using two different methods,namely,the MCDHF method and the finite-field method.The results show that these two methods are in excellent agreement.
文摘With the continuous improvement of the medical industry’s requirements for the professional capabilities of nursing talents,traditional nursing teaching models can hardly meet the needs of complex nursing work in neurology.This paper focuses on nursing education for neurology nursing students and explores the construction of the“one-on-one”teaching model,aiming to achieve a paradigm shift in nursing education.By analyzing the current status of neurology nursing education,this paper identifies the problems in traditional teaching models.Combining the advantages of the“one-on-one”teaching model,it elaborates on the construction path of this model from aspects such as the selection and training of teaching instructors,the design of teaching content,the innovation of teaching methods,and the improvement of the teaching evaluation system.The research shows that the“one-on-one”teaching model can significantly enhance nursing students’mastery of professional knowledge,clinical operation skills,communication skills,and emergency response capabilities,as well as strengthen their professional identity and sense of responsibility.It provides an effective way to cultivate high-quality nursing talents who can meet the needs of neurology nursing work and promotes the innovative development of nursing education.
基金Hangzhou Philosophy and Social Science Planning Program(24JD15)。
文摘National Fire codes,mandated by government authorities to tackle technical challenges in fire prevention and control,establish fundamental standards for construction practices.International collaboration in fire protection technologies has opened avenues for China to access a wealth of documents and codes,which are crucial in crafting regulations and developing a robust,scientific framework for fire code formulation.However,the translation of these codes into Chinese has been inadequate,thereby diminishing the benefits of technological exchange and collaborative learning.This underscores the necessity for comprehensive research into code translation,striving for higher-quality translations guided by established translation theories.In this study,we translated the initial segment of the NFPA 1 Fire Code into Chinese and examined both the source text and target text through the lens of Translation Shift Theory,a concept introduced by Catford.The conclusion culminated in identifying four key shifts across various linguistic levels:lexis,sentences,and groups,to ensure an accurate and precise translation of fire codes.This study offers a through and lucid explanation of how the translator integrates Catford’s theories to solve technical challenges in NFPA 1 Fire Code translation,and establish essential standards for construction translation practices.
基金the National Natural Science Foundation of China(NSFC)(Grant Nos.42030105,42274011,42074019,41974034,42204006)。
文摘Highly accurate international height reference frames with long-term stability,global consistency,and homogeneity are crucial for monitoring sea level variations,understanding climate change,managing disasters,and supporting other applications that benefit scientific research and societal well-being.Currently,there are over 100 local height reference systems worldwide.Unifying these systems is a pivotal step toward constructing international height reference frames.The method introduced in this study-the gravity frequency shift via Satellite Frequency Signal Transfer(SFST)-represents a groundbreaking relativistic geodetic approach,demonstrating its potential to surpass the constraints of conventional techniques.The advent of high-precision optical atomic clocks(OAC)with an accuracy level of 1×10^(-18) has facilitated this method's implementation.The International Association of Geodesy(IAG)has established the International Height Reference System(IHRS)and its practical realization,the International Height Reference Frame(IHRF).Our study focuses on two neighbouring height systems:the China Height System(CHS)and the Nepal Height System(NHS),separated by the Himalayas and the Xizang plateau.We aim to unify these two systems by determining the geopotential and orthometric height differences between their respective height datum stations:the Qingdao Height Datum Station(QHDS)and the Madar Height Datum Station(MHDS)using a simulation experiment with the method mentioned above.Using an OAC with an accuracy of 1×10^(-18),we identified a geopotential difference of-8.348±0.464 m^(2)s^(-2) and an orthometric height difference of 0.786±0.047 m between QHDS and MHDS.These results suggest that the introduced method could unify any two height systems with fewcentimeter-level precision,emphasizing its significance in contributing to the construction of the IHRS/IHRF with today's required precision.In summary,the SFST technique is a novel geodetic method that offers an alternative for height system unification,delivering centimeter-level precision,surpassing traditional methods,and supporting the development of the IHRF.
文摘The phenomenon of verbal-to-nominal shift(hereafter referred to as“V-N shift”)exists in both English and Chinese.It reflects both the universal conceptual metonymic thinking and the principle of linguistic economy.Focusing on conceptual metonymy theory and combined with the Event Idealized Cognitive Model(ICM),this paper systematically compares the V-N shift phenomenon in English and Chinese.The study shows that English and Chinese V-N shifts share the core cognitive mechanism of“conceptual proximity within the Event ICM”,while significant differences exist in type distribution and usage frequency.This analysis not only helps deepen the understanding of the cognitive logic behind English and Chinese V-N shifts but also provides a new perspective for the study of word-class conversion and the relationship between language and thinking.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52171251 and U21062251)Program of Science and Technology Innovation of Dalian(Grant No.2022JJ12GX036).
文摘The degradation and nonlinear interactions of a two-breather solution of the Mel’nikov equation are analyzed.By modulating the phase shift and limit method,we prove that in different regions near the non-singular boundaries,there are four kinds of solutions with repulsive interaction or attractive interaction in addition to the two-breather solution.They are the interaction solution between soliton and breather,the two-soliton solution,and the two-breather solution with small amplitude,which all exhibit repulsive interactions;and the two-breather solution with small amplitude,which exhibits attractive interaction.Interestingly,a new breather acts as a messenger to transfer energy during the interaction between two breather solutions with small amplitude.
基金supported by grants from the National Natural Science Foundation of China(Grant No.32271733)Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515011045)+1 种基金Science and Technology Projects in Guangzhou(Grant No.2023A04J0121)SCNU Training Program of Innovation for Undergraduates,China。
文摘Anthropogenic climate change is altering species distributions globally.While species distributions are expected to shift to higher latitudes and elevations under global warming,empirical evidence on distribution shifts is mixed,and factors mediating the direction and magnitude of range shifts remain unclear.Using a dataset of 132new provincial records for 96 resident bird species from 2000 to 2023,we measured geographic distance,latitudinal shift,and temperature shift from each new record to the historical range for each species to test for poleward shifts.We assessed taxonomic variation in the magnitude of range shifts and used phylogenetic generalized linear mixed models to quantify relationships between species traits and the extent of range shifts.Our results revealed that new records occurred at a mean geographic distance of 420 km from historical ranges,with mean latitudinal shifts of+1.68°(poleward)and temperature shifts of-1.33℃(toward colder climates).The magnitude of geographic range shifts was strongly constrained by phylogenetic relatedness.Habitat breadth,habitat openness,and centroid latitude of historical ranges emerged as significant predictors of range shifts.Our results suggest that resident bird species'geographic ranges in China are shifting poleward,but the magnitude of these shifts is non-random across lineages.Species with broader habitat preferences and those from warmer climates are more likely to shift farther from their historical ranges and toward higher latitudes.This study emphasizes taxonomic variation in species range shifts and highlights the need for species-and site-specific conservation strategies under global warming.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204412,12274423,12174402,12393821,and 12004124)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB0920100 and XDB0920101)support from the Natural Sciences and Engineering Research Council of Canada.All calculations were performed on the APM-Theoretical Computing Cluster(APM-TCC).
文摘Standard perturbation theory is employed to calculate the mass shifts of the 2^(1)S_(0)-^(3)S_(1)and 2^(3)S_(1)-2^(3)P_(J)transitions for^(4,6,8)He.High-precision results are obtained for the mass shifts in the isotope pairs 6He-4He and 8He-4He,with uncertainties below 1 part per million(ppm).Our analysis provides a complete set of isotope-shift results and systematically examines their sensitivity to nuclear charge-radius differences.Once experimental measurements reach a precision comparable to that of the calculated mass shifts,the squared differences of nuclear charge radii can be determined with an accuracy of approximately 0.4%-0.6%,representing an order-of-magnitude improvement over current values.
文摘Gait recognition,a promising biometric technology,relies on analyzing individuals' walking patterns and offers a non-intrusive and convenient approach to identity verification.However,gait recognition accuracy is often compromised by external factors such as changes in viewpoint and attire,which present substantial challenges in practical applications.To enhance gait recognition performance under diverse viewpoints and complex conditions,a global-local part-shift network is proposed in this paper.This framework integrates two novel modules:the part-shift feature extractor and the dynamic feature aggregator.The part-shift feature extractor strategically shifts body parts to capture the intrinsic relationships between non-adjacent regions,enriching the recognition process with both global and local spatial features.The dynamic feature aggregator addresses long-range dependency issues by incorporating multi-range temporal modeling,effectively aggregating information across parts and time steps to achieve a more robust recognition outcome.Comprehensive experiments on the CASIA-B dataset demonstrate that the proposed global-local part-shift network delivers superior performance compared with state-of-the-art methods,highlighting its potential for practical deployment.
文摘According to the 2024 China Marine Economy Statistical Bulletin(hereinafter“the Bulletin”),China’s marine economy surpassed the 10 trillion yuan(US$1.38 trillion)mark for the first time in 2024,0.9 percentage points higher than the growth rate of the national GDP.
基金Project supported by the Natural Science Foundation of Jilin Province of China(Grant No.20230101014JC)the National Natural Science Foundation of China(Grant No.12374265)。
文摘We investigate theoretically the effects of chirped laser pulses on high-order harmonic generation(HHG)from solids.We find that the harmonic spectra display redshifts for the driving laser pulses with negative chirp and blueshifts for those with positive chirp,which is due to the change in the instantaneous frequency of the driving laser for different chirped pulses.The analysis of crystal-momentum-resolved(k-resolved)HHG reveals that the frequency shifts are equal for the harmonics generated by different crystal momentum channels.The frequency shifts in the cutoff region are larger than those in the plateau region.With the increase of the absolute value of the chirp parameters,the frequency shifts of HHG become more significant,leading to the shifts from odd-to even-order harmonics.We also demonstrate that the frequency shifts of harmonic spectra are related to the duration of the chirped laser field,but are insensitive to the laser intensity and dephasing time.
基金the National Natural Science Foundation of China(Grant Nos:42372253 and 42072260)the Youth Innovation Team of Shaanxi Universitiesthe Science and Technology Project of PetroChina(No.2023ZZ0201).
文摘An enhanced understanding of the history of the western Qinling-Dabie orogen is pivotal in reconstructing geological processes of the east Asian mainland.However,less attention has been paid to its early-stage uplift-erosion history after closure of surrounding oceanic basins at the mid-Paleozoic.In this study,we undertook a comprehensive study including paleocurrent reconstruction,sandstone petrology,and detrital zircon U-Pb dating on Late Carboniferous to Early Permian successions in the southern Ordos neighboring the northern Qinling-Dabie.New provenance data reveal a significant provenance shift at the Carboniferous-Permian transition.The older Benxi Formation was sourced southerly from the North Qinling Terrane that provided detritus mostly of Neoproterozoic and Early Paleozoic ages.In contrast,Early Permian samples yield age relation dominated by Neoarchean,Paleoproterozoic,Early Paleozoic,and Late Paleozoic age populations,with a significant gap of ca.1600-550 Ma,implying a sediment derivation from the Inner Mongolia Continental Arc.This shift is further verified by paleocurrent transition from south to north then.We suggest that the North Qinling Terrane experienced a significant uplift history from ca.500 Ma and remained as a highland until end-Carboniferous.From Early Permian,the North Qinling Terrane was submerged,covered by widespread deltaic sedimentation there.Northerly source from the Inner Mongolia Continental Arc began to be accumulated in the northern flank of the North Qinling Terrane,before termination approximately along the southern North Qinling Terrane,where shallow-water carbonate shelf sedimentation sustained from Devonian to Triassic.This new finding indicates that uplift of the North Qinling Terrane lasted about 150 Ma after the Proto-Tethys Ocean closure.
基金supported by the National Natural Science Foundation of China(Nos.22004046 and 22074052)the Science and Technology Developing Foundation of Jilin Province of China(Nos.20240404044ZP,20230101033JC and 20220505015ZP).
文摘The aggressive nature and high mortality rate of lung cancer underscore the imperative need for early diagnosis of the disease.Thus,aminopeptidase N(APN),a potential biomarker for lung cancer,should be thoroughly investigated in this context.This report describes the development of HA-apn,a novel near-infrared fluorescent probe,specifically engineered for the sensitive detection of endogenous APN.Characterized by its high selectivity,straightforward molecular architecture,and suitable optical properties,including a long-wavelength emission at 835 nm and a large Stokes shift of 285 nm,HA-apn had high efficacy in identifying overexpressed APN in tumor cells,which shows its potential in pinpointing malignancies.To further validate its applicability and effectiveness in facilitating the direct and enhanced visualization of pulmonary alterations,an in situ lung cancer mouse model was employed.Notably,HAapn was applied for in vivo imaging of APN activity in the lung cancer mouse model receiving the probe through aerosol inhalation,and rapid and precise diagnostic results were achieved within 30min postadministration.Overall,HA-apn can be applied as an effective,non-intrusive tool for the rapid and accurate detection of pulmonary conditions.
基金supported by a key project of the National Natural Science Foundation of China[grant number 42192563]。
文摘Against the backdrop of climate change,the activity of tropical cyclones(TCs)has captured widespread attention.Observational datasets indicate a declining trend in the genesis longitude of western North Pacific(WNP)TCs.This study investigates the zonal changes of WNP TCs with CMIP6-HighResMIP models.These models capture the genesis density of WNP TCs fairly well.The results reveal a westward shift in TC genesis longitude.This trend is associated with the significant reduction in the TC frequency over the southeastern WNP.The study also discusses changes in large-scale circulation patterns and the impact of the strengthening Pacific Walker circulation.
