In order to further explore the rich connotation of Huai'an historical and cultural space and the Grand Canal culture,the synchronicity of urban spatial pattern and historical buildings of Huai'an was studied ...In order to further explore the rich connotation of Huai'an historical and cultural space and the Grand Canal culture,the synchronicity of urban spatial pattern and historical buildings of Huai'an was studied under the guidance of synchronic theory and method.It is found that there are the identity and reality law of the development and change of Huai'an historical and cultural space and the Grand Canal cultural system,and it is deduced that there is a spiraling systematic structure chain between the historical and cultural space of Huai'an and the Grand Canal culture,which provides a theoretical reference for promoting the deepening construction of regional culture,the Grand Canal cultural belt and national cultural parks.展开更多
The sediment discharge from the Yangtze River Basin has a stepwise decreasing trend in recent years. The impounding of the Three Gorges Reservoir exacerbated this de- creasing trend and affected the change of the susp...The sediment discharge from the Yangtze River Basin has a stepwise decreasing trend in recent years. The impounding of the Three Gorges Reservoir exacerbated this de- creasing trend and affected the change of the suspended sediment concentration （SSC） in the Yangtze River Estuary through the transmission effect. The SSC data of the Yangtze River Estuary during 1959-2012 showed that： （1） The SSC in the South Branch of the Yang- tze River in the estuary and in the off-shore sea area displayed decreasing trends and de- creased less towards the sea. At the same time, the difference in decreasing magnitude be- tween SSC and sediment discharge became bigger towards the sea. （2） For the North Branch the preferential flow did not change much but the SSC tended to decrease, which was mainly caused by the decrease of SSC in the South Branch and China East Sea. （3） Due to the de- creased runoff and the relatively strengthened tide, the peak area of the SSC in the bar shoal section in 2003-2012 moved inward for about 1/6 longitude unit compared with that in 1984-2002, and the inward-moving distance was in the order of flood season 〉 annual average 〉 dry season. （4） In the inlet of the South Passage, the SSC decreased mainly because the increase caused by resuspension and shore-groove exchange was less than the decrease caused by the sharp SSC decrease in the basin and the sea areas. The reverse was true in the middle section, where the SSC showed an increasing trend. （5） In the inlet of the North Passage, under the combined influence of decreased flow split and sediment split ratios, the decreased SSC in the basin and the sea area and decreased amount of resuspension, the SSC displayed a decreasing trend. In the middle section, because the increased amount caused by sediment going over the dyke was markedly more than the decreased amount caused by external environments, the SSC tended to increase. Holistically, the sharp decrease in sediment discharge caused synchronized SSC decreases in the Yangtze River Estuary. But there were still areas, where the SSC displayed increasing trends, indicatingsynchronicity and difference in the response of SSC to the sharp decrease in sediment discharge from the basin.展开更多
Bamboos are widely distributed in mainland Southeast Asia and have abundant biomass. They are characterized by prolonged vegetative growth and semelparity. Where bamboos are dominant, their synchronous flowering and d...Bamboos are widely distributed in mainland Southeast Asia and have abundant biomass. They are characterized by prolonged vegetative growth and semelparity. Where bamboos are dominant, their synchronous flowering and death has a major impact on forest vegetation. Although the small-scale dynamics of this process have become clearer in recent years, the history, geographical scale and synchronicity of bamboo flowering over broad areas remains unknown. This study focused on the flowering history of six bamboo species, Bambusa tulda, Cephalostachyum virgatum, Dendrocalamus hamiltonii, Dendrocalamus membranaceus, Indosasa sinica and Oxytenanthera parvifolia, over 40 years across a broad area of northern Laos. We also examined the synchronicity of flowering in D. membranaceus. We visited 49 villages in northern Laos and surveyed knowledgeable inhabitants about bamboo flowering history. The timing, scale and synchronicity of gregarious flowering varied among species. D. hamiltonii and D. membranaceus showed higher flowering synchronicity than other species. All the species except I. sinica had both sporadic and gregarious flowering traits, and showed conspicuous variability in their flowering scale. The flowering bamboo population at two gregarious flowering sites for D. membranaceus was surveyed. While thisspecies had the highest synchronicity in this study, its synchronicity was lower than other species in previous studies worldwide. We found that the gregarious flowering of bamboos in northern Laos over the last 40 years showed lower synchronicity than bamboo flowering reported in other areas of the world. The historical dynamics and scale of bamboo flowering must be further clarified to understand the vegetation composition of this area.展开更多
This article aims to provide a brief overview of the relevance of new findings about the Fibonacci Life Chart Method (FLCM) for understanding synchronicity. The FLCM is reviewed first, including an exposition of the g...This article aims to provide a brief overview of the relevance of new findings about the Fibonacci Life Chart Method (FLCM) for understanding synchronicity. The FLCM is reviewed first, including an exposition of the golden section model, and elaboration of a new harmonic model. The two models are then compared to illuminate several strengths and weaknesses in connection with the following four major criteria regarding synchronicity: explanatory adequacy;predictability of future synchronicities;simplicity of the model;and generalizability to other branches of knowledge. The review indicates that both models appear capable of simulating nonlinear and fractal dynamics. Hybrid approaches that combine both models are feasible and necessary for projects that aim to experimentally address synchronicity.展开更多
Synchronicity involves the experience of personal meaning entangled with ambiguous coincidences in time. Ambiguity results from incomplete information about the chances of various events occurring. The problem that th...Synchronicity involves the experience of personal meaning entangled with ambiguous coincidences in time. Ambiguity results from incomplete information about the chances of various events occurring. The problem that this study addresses is the lack of empirical research on synchronicity. This study sought to address this problem by exploring the astrological hypothesis that planetary transits predict synchronicity events. Synchronicities were compared with the probability distributions of planetary transits. In comparison with the base rate prediction, planetary transits were not a significant predictor of synchronicity events. The findings of this study provide new insight into the complex, multifaceted, and ambiguous phenomenon of synchronicity. The concept of ambiguity tolerance plays a significant role in synchronicity research since ambiguity cannot be completely eliminated.展开更多
In this work we analyze the concept of time dilation in its application to the rate of moving clocks. The rates of two equiform elementary electromagnetic clocks of different orientations relative to their direction o...In this work we analyze the concept of time dilation in its application to the rate of moving clocks. The rates of two equiform elementary electromagnetic clocks of different orientations relative to their direction of motion are computed on the basis of relativistic transformations of force and coordinates for the case when the clocks are at rest in a stationary reference frame and for the case when they are moving at constant speed relative to the stationary reference frame. It is shown that, although both clocks run slower when they are moving than when they are at rest, the rate of the moving clocks is affected by their orientation relative to their direction of motion, rather than by the kinematic (relativistic) time dilation as it is now generally assumed. The implication of this result for the experimental proofs of the existence of the kinematic the dilation is discussed.展开更多
Objectives To quantitatively analyze the longitudinal myocardial systolic and diastolic velocities and time intervals of the left ventricle in normal subjects, and to explore the value of pulsed Doppler tissue imaging...Objectives To quantitatively analyze the longitudinal myocardial systolic and diastolic velocities and time intervals of the left ventricle in normal subjects, and to explore the value of pulsed Doppler tissue imaging （DTI） for the assessment of left ventricular systolic and diastolic synchronicity. Methods Twenty and six healthy subjects were studied by pulsed DTI. The septal and lateral, anterior and inferior walls of the left ventricle were displayed respectively, and basal and middle segments of each wall were selected for myocardial motion spectrum sampling. DTI parameters were： peak systolic myocardial velocity （s）, regional pre-ejection period （PEP）, time to the peak of s wave （Ts）, regional ejection time （ET） ; peak early diastolic velocity （e）, peak late diastolic velocity （a）, e/a ratio, time to the beginning of e wave （QE）, time to the peak of e wave （Te） and regional isovolumic relaxation time （IVRT）. Results The e and e/a were significantly different among basal segments, and s and e/a were significantly different among middle segments, with the highest value in lateral segments and the lowest value in septal segments. The s, e and a were all significantly higher in basal segments than middle segments. None of the systolic time intervals （PEP, Ts and ET） and diastolic time intervals （QE, Te and IVRT） were significantly different among basal segments and middle segments, neither were they when basal segment was compared with middle segment. Conclusions In normal subjects, the longitudinal myocardial systolic and diastolic velocities of the left ventricle are not homogeneous, but the contraction and relaxation are highly synchronized. Pulsed DTI can be used to quantitatively analyze the systolic and diastolic synchronicity of the heart.展开更多
Background Using tissue Doppler imaging and conventional echocardiographic technique, we examined the cardiac function and synchronicity in individuals with isolated right bundle branch block （RBBB） or left bundle b...Background Using tissue Doppler imaging and conventional echocardiographic technique, we examined the cardiac function and synchronicity in individuals with isolated right bundle branch block （RBBB） or left bundle branch block （LBBB） and assessed the relationship between QRS duration and synchronicity.展开更多
Background Mechanical asynchrony is an important parameter in predicting the response to cardiac resynchronization therapy, but detailed knowledge about cardiac timing in healthy persons is scarce. Therefore, in the c...Background Mechanical asynchrony is an important parameter in predicting the response to cardiac resynchronization therapy, but detailed knowledge about cardiac timing in healthy persons is scarce. Therefore, in the current study, we sought to investigate the physiological status of interventricular synchronicity using pulse wave flow and tissue Doppler imaging in a healthy Chinese population. Methods Eighty-eight healthy volunteers underwent standard flow and tissue Doppler echocardiographic examinations. Ventricular inflow and outflow pulse wave flow Doppler patterns were recorded together with annulus pulse tissue Doppler imaging. Time intervals from the beginning of the QRS complex to the onset, peak and end of each wave were measured. Results The onsets of systole between left and right ventricles were highly synchronized by both imaging modalities. However, the left ventricle reached the peak flow ejection and peak mechanical contraction earlier than the right ventricle, （165.61±26.23） ms vs. （204.3±34.55） ms （P 〈0.01） and （133.62±26.19） ms vs. （191.25±38.47） ms （P 〈0.01）. Time to peak early diastolic relaxation was earlier in the left ventricle than in the right heart, （500.23±56.52） ms vs. （524.94±47.42） ms （P 〈0.01 ）. Conclusions Left and right ventricles were well synchronized at the onsets of systole and diastole even though interventricular peak systolic and peak early diastolic dyssynchrony was observed in healthy people by pulse wave Doppler imaging. In addition, diastolic timing events were slightly affected by age and gender.展开更多
We analyze whether product market advertising has a spillover effect on stock price synchronicity by transmitting firm-specific information to the capital market and attracting more investor attention.Using a sample o...We analyze whether product market advertising has a spillover effect on stock price synchronicity by transmitting firm-specific information to the capital market and attracting more investor attention.Using a sample of Chinese listed firms from 2009 to 2017,we find that firms with greater advertising expenditures have lower stock price synchronicity.The results are robust after we address endogeneity concerns.In accord with our hypothesis that product market advertising increases the amount of firm-level information capitalized into stock prices through the information channel,we find that the impact of advertising on synchronicity is more pronounced for firms with a higher degree of information asymmetry and firms in the consumer-product industry.Further tests show that product market advertising enhances the ability of current period returns to reflect future earnings,and thus rules out that the negative relationship between advertising and synchronicity is driven by noise trading.Our results imply that product market advertising plays an informative role and improves information efficiency in a capital market.展开更多
Based on a sample of Chinese A-share listed firms from 2015 to 2018,this paper studies the impact of annual report comment letters(ARCLs)on firm stock price synchronicity.We find that after firms receive ARCLs,their s...Based on a sample of Chinese A-share listed firms from 2015 to 2018,this paper studies the impact of annual report comment letters(ARCLs)on firm stock price synchronicity.We find that after firms receive ARCLs,their stock price synchronicity decreases.Moreover,the longer the ARCLs and the more negative the ARCLs’tone,the lower the resulting stock price synchronicity.The mechanism test shows that after firms receive ARCLs,the firms’information disclosure increases in quantity and quality,external media attention increases,and the firms’governance improves,reducing their stock price synchronicity.Further research shows that this negative association is more significant in firms with higher information asymmetry.This paper shows that the ARCL,an innovative application of the capital market supervision philosophy,is conducive to improving the quality of listed firms and to the healthy development of the capital market.展开更多
We designed and investigated a passive synchronized mode-locked fiber laser.The device utilizes a dual-cavity structure driven by the nonlinear polarization rotation(NPR)mechanism.Stable mode-locking is attained by sy...We designed and investigated a passive synchronized mode-locked fiber laser.The device utilizes a dual-cavity structure driven by the nonlinear polarization rotation(NPR)mechanism.Stable mode-locking is attained by synergistically controlling gain,polarization state,and optical path length in two symmetric sub-cavities.Experiments proved that repetition rate of the sub-cavities can be adjusted via the time delay line(TDL)to achieve synchronized mode-locking.The system stably generates multi-wavelength pulses at a single repetition frequency,evidenced by multiple spectral peaks and equidistant pulse sequences.These findings facilitate the development of high-performance multi-wavelength ultrashort pulse sources,crucial for optical communications,spectral analysis,and remote sensing.展开更多
Lip synchronization serves as a core technology for enabling natural interactions in digital virtual humans.However,it faces challenges such as insufficient dynamic correspondence between speech and lip movements and ...Lip synchronization serves as a core technology for enabling natural interactions in digital virtual humans.However,it faces challenges such as insufficient dynamic correspondence between speech and lip movements and inadequate modeling of image details.To address these limitations,a comprehensively optimized lip synchronization framework extending the Wav2Lip architecture was proposed in this study.Firstly,based on the Wav2Lip model,a facial region extraction strategy using facial keypoints was designed,which effectively enhances the robustness of facial alignment during lip synchronization for digital virtual humans.Then,a cross-modal attention fusion module between visual and speech features was introduced to improve cross-modal information fusion,and a dynamic receptive field convolution module was developed in the generation branch to enhance the modeling performance of the lip region.Finally,experiments were conducted on the VFHQ dataset.The proposed method was compared with Wav2Lip,VideoRetalking,and DI-Net models,and its performance was evaluated using three metrics:LSE-C,CSIM,and FID.Experimental results showed that the proposed method achieves significant improvements in synchronization accuracy and image fidelity,providing an efficient and feasible solution for lip-synthesis tasks of digital virtual humans.展开更多
Let T_(n) and S_(n) be the full transformation semigroup and the symmetric group on X_(n)={1,2,...,n},respectively.Let G be a transitiveimprimitive subgroupof S_(n) with nontrivial blocksΔand letαbe a transformation...Let T_(n) and S_(n) be the full transformation semigroup and the symmetric group on X_(n)={1,2,...,n},respectively.Let G be a transitiveimprimitive subgroupof S_(n) with nontrivial blocksΔand letαbe a transformation in T_(n)\S_(n).The kernel ofαis the partition of X_(n) induced by the equivalence relation{(x,y)|xα=yα};the kernel type ofαis the partition of n given by the sizes of the parts of the kernel.A transformation semigroup is called synchronizing if it contains a constant map.Then a group G synchronizes a transformationαif the semigroup(G,α)contains a constant map.In this paper,we study a transitive imprimitive permutation group G together with a non-invertible transformationαthat generate a synchronizing semigroup.We mainly discuss 7 cases where G synchronizes a special transformationαwith each kernel class A_(i)(A_(1)j)satisfying|A_(i)∩Δ|=1(|A_(1)j∩Δ|=1)for all blocksΔofG,that is,the kernel type ofαis(|A_(1)|,1,...,1),(|A_(1)1|,...,|A_(1m)|,|A_(2)|,...,|Ar|),or(|A_(1)|,...,|A_(t)|,1,...,1),or the rank is 2,3,4,or n-2.展开更多
This paper examines the impact on stock return synchronicity of information provided by people who neighbor firms.Neighboring people have inherent advantages in acquiring and interpreting information.We employed novel...This paper examines the impact on stock return synchronicity of information provided by people who neighbor firms.Neighboring people have inherent advantages in acquiring and interpreting information.We employed novel satellite nighttime light data as a proxy for information held by neighboring people.Our analyses confirmed that brighter nighttime light was related to greater and better-quality information production.Using a sample of 18,963 firm-year observations over the 2000-2013 period,we found that information from nearby people facilitated the incorporation of firm-specific information into stock prices,resulting in lower stock return synchronicity.The results were robust when using the slope as an instrumental variable and were supported by various sensitivity checks.The effect of nighttime light intensity was more pronounced for firms operating across multiple geographic regions or diverse industries,those situated near more parks and shopping malls,and those with fewer institutional investors and less media coverage.展开更多
Optical non-reciprocity is a fundamental phenomenon in photonics.It is crucial for developing devices that rely on directional signal control,such as optical isolators and circulators.However,most research in this fie...Optical non-reciprocity is a fundamental phenomenon in photonics.It is crucial for developing devices that rely on directional signal control,such as optical isolators and circulators.However,most research in this field has focused on systems in equilibrium or steady states.In this work,we demonstrate a room-temperature Rydberg atomic platform where the unidirectional propagation of light acts as a switch to mediate time-crystalline-like collective oscillations through atomic synchronization.展开更多
When the converter bus voltage of a voltage source converter-based high voltage direct current(VSC-HVDC)system drops below a certain predetermined threshold,the system enters low-voltage ride-through(LVRT)mode to avoi...When the converter bus voltage of a voltage source converter-based high voltage direct current(VSC-HVDC)system drops below a certain predetermined threshold,the system enters low-voltage ride-through(LVRT)mode to avoid overcurrent and potential equipment failure,during which it operates as a controlled current source.The influence mechanism of LVRT control strategies on short-circuit current and overall system stability remains not yet fully and systematically investigated.First,this paper provides an overview of several LVRT strategies for VSC-HVDC systems and examines their effects on short-circuit current contribution.Next,it analyzes in detail the mechanisms through which active and reactive currents injected during LVRT impact system frequency stability,voltage stability,and synchronization stability.To address these interrelated issues,an optimized and comprehensive LVRT strategy incorporating short-circuit current constraints is proposed.The approach determines the active current ratio based on system frequency stability requirements and dynamically adjusts the active current recovery rate via phase control of the VSC-HVDC bus.The remaining capacity is allocated to reactive current support,thereby enhancing voltage and synchronization stability while maintaining sufficient short-circuit current margin and system frequency stability.Finally,simulations conducted on the PSS/E platform,using actual grid data from a selected cross-section system,validate convincingly the effectiveness of the proposed parameter optimization strategy for VSC-HVDC low-voltage ride-through.展开更多
In a multiple voltage source converter(VSC)system,the nonlinear characteristics of phase-locked loops(PLLs)and their interactions have a significant influence on the synchronization stability of converters.In this pap...In a multiple voltage source converter(VSC)system,the nonlinear characteristics of phase-locked loops(PLLs)and their interactions have a significant influence on the synchronization stability of converters.In this paper,these influences are investigated from the perspective of the time domain.First,a novel time-domain model of the multi-VSC system is obtained by using a multi-scale method.On this basis,a stability criterion is proposed to assess the synchronization stability of the system.Then,the accuracy of the time-domain model and its stability criterion in various conditions are discussed.Moreover,the negative impact of the interaction on the system is quantified.Finally,the above theoretical analysis is also verified in the controller hardware-in-the-loop(CHIL)experiments.展开更多
This paper is dedicated to fixed-time passivity and synchronization for multi-weighted spatiotemporal directed networks.First,to achieve fixed-time passivity,a type of decentralized power-law controller is developed,i...This paper is dedicated to fixed-time passivity and synchronization for multi-weighted spatiotemporal directed networks.First,to achieve fixed-time passivity,a type of decentralized power-law controller is developed,in which only one parameter needs to be adjusted in the power-law terms;this greatly decreases the inconvenience of parameter adjustment.Second,several fixed-time passivity criteria with LMI forms are derived by using a Gauss divergence theorem to deal with the spatial diffusion of nodes and by applying the Hölder’s inequality to dispose rigorously the power-law term greater than one in the designed control scheme;this improves the previous theoretical analysis.Additionally,the fixed-time synchronization of spatiotemporal directed networks with multi-weights is addressed as a direct result of fixed-time strict passivity.Finally,a numerical example is presented in order to show the validity of the theoretical analysis.展开更多
Modern/distributed electric energy systems,with ever larger penetration of renewable(photovoltaic,wind,wave,and hydro)energy sources and time-variable outputs,are in need of stronger/higher frequency and alternating c...Modern/distributed electric energy systems,with ever larger penetration of renewable(photovoltaic,wind,wave,and hydro)energy sources and time-variable outputs,are in need of stronger/higher frequency and alternating current(AC)(direct current(DC))voltage control.In fact,faster and more stable active and reactive power in the presence of frequency and voltage sags and swells is needed.Power electronics-controlled variable speed generators do not have enough energy storage(inertia)for the scope(static synchronous compensators(STATCOMs)included).This is because power electronics tends to decouple the generator from the power system.While virtual inertia control in doubly fed induction generators(DFIGs)offers a partial solution to these problems,a more robust and comprehensive framework is required for advanced grid support.This is how,by extending the dual-excitation principles,the dualaxis excited electric synchronous generators(DE-SG)provide superior flexibility in two variants summarized here:as a multifunctional DFIG and dual-axis vs.single-axis excited synchronous generator(SG),and as a synchronous condenser(SC),with dual DC and AC excitation(as a no-load DFIG with inertia wheel),where variable speed is used to accelerate/decelerate the SC and thus provide additional assistance in frequency stabilization.These solutions,good for short-time transients,are not meant,however,to replace the large bidirectional energy storage systems(pump-hydro,hydrogen,batteries,etc.)which are crucial for the daily inherent variations of output energy in modern power systems with multiple power sources.The present paper offers a summary of techniques used in the dual-axis excited vs.single-axis excited SGs(SE-SGs),and SCs topologies,modeling,and control for better stability in modern multiple-source energy systems.This survey includes multiple case studies to shed light on prominent methods.展开更多
基金Supported by the Philosophy and Social Science Project of Jiangsu Province,China(2024SJYB1403).
文摘In order to further explore the rich connotation of Huai'an historical and cultural space and the Grand Canal culture,the synchronicity of urban spatial pattern and historical buildings of Huai'an was studied under the guidance of synchronic theory and method.It is found that there are the identity and reality law of the development and change of Huai'an historical and cultural space and the Grand Canal cultural system,and it is deduced that there is a spiraling systematic structure chain between the historical and cultural space of Huai'an and the Grand Canal culture,which provides a theoretical reference for promoting the deepening construction of regional culture,the Grand Canal cultural belt and national cultural parks.
基金Fund from the Ministry of Science and Technology of China,No.2010CB429002National Natural Science Foundation of China,No.51209112No.41331174
文摘The sediment discharge from the Yangtze River Basin has a stepwise decreasing trend in recent years. The impounding of the Three Gorges Reservoir exacerbated this de- creasing trend and affected the change of the suspended sediment concentration （SSC） in the Yangtze River Estuary through the transmission effect. The SSC data of the Yangtze River Estuary during 1959-2012 showed that： （1） The SSC in the South Branch of the Yang- tze River in the estuary and in the off-shore sea area displayed decreasing trends and de- creased less towards the sea. At the same time, the difference in decreasing magnitude be- tween SSC and sediment discharge became bigger towards the sea. （2） For the North Branch the preferential flow did not change much but the SSC tended to decrease, which was mainly caused by the decrease of SSC in the South Branch and China East Sea. （3） Due to the de- creased runoff and the relatively strengthened tide, the peak area of the SSC in the bar shoal section in 2003-2012 moved inward for about 1/6 longitude unit compared with that in 1984-2002, and the inward-moving distance was in the order of flood season 〉 annual average 〉 dry season. （4） In the inlet of the South Passage, the SSC decreased mainly because the increase caused by resuspension and shore-groove exchange was less than the decrease caused by the sharp SSC decrease in the basin and the sea areas. The reverse was true in the middle section, where the SSC showed an increasing trend. （5） In the inlet of the North Passage, under the combined influence of decreased flow split and sediment split ratios, the decreased SSC in the basin and the sea area and decreased amount of resuspension, the SSC displayed a decreasing trend. In the middle section, because the increased amount caused by sediment going over the dyke was markedly more than the decreased amount caused by external environments, the SSC tended to increase. Holistically, the sharp decrease in sediment discharge caused synchronized SSC decreases in the Yangtze River Estuary. But there were still areas, where the SSC displayed increasing trends, indicatingsynchronicity and difference in the response of SSC to the sharp decrease in sediment discharge from the basin.
基金supported by JSPS KAKENHI(Grant Number 22241012)
文摘Bamboos are widely distributed in mainland Southeast Asia and have abundant biomass. They are characterized by prolonged vegetative growth and semelparity. Where bamboos are dominant, their synchronous flowering and death has a major impact on forest vegetation. Although the small-scale dynamics of this process have become clearer in recent years, the history, geographical scale and synchronicity of bamboo flowering over broad areas remains unknown. This study focused on the flowering history of six bamboo species, Bambusa tulda, Cephalostachyum virgatum, Dendrocalamus hamiltonii, Dendrocalamus membranaceus, Indosasa sinica and Oxytenanthera parvifolia, over 40 years across a broad area of northern Laos. We also examined the synchronicity of flowering in D. membranaceus. We visited 49 villages in northern Laos and surveyed knowledgeable inhabitants about bamboo flowering history. The timing, scale and synchronicity of gregarious flowering varied among species. D. hamiltonii and D. membranaceus showed higher flowering synchronicity than other species. All the species except I. sinica had both sporadic and gregarious flowering traits, and showed conspicuous variability in their flowering scale. The flowering bamboo population at two gregarious flowering sites for D. membranaceus was surveyed. While thisspecies had the highest synchronicity in this study, its synchronicity was lower than other species in previous studies worldwide. We found that the gregarious flowering of bamboos in northern Laos over the last 40 years showed lower synchronicity than bamboo flowering reported in other areas of the world. The historical dynamics and scale of bamboo flowering must be further clarified to understand the vegetation composition of this area.
文摘This article aims to provide a brief overview of the relevance of new findings about the Fibonacci Life Chart Method (FLCM) for understanding synchronicity. The FLCM is reviewed first, including an exposition of the golden section model, and elaboration of a new harmonic model. The two models are then compared to illuminate several strengths and weaknesses in connection with the following four major criteria regarding synchronicity: explanatory adequacy;predictability of future synchronicities;simplicity of the model;and generalizability to other branches of knowledge. The review indicates that both models appear capable of simulating nonlinear and fractal dynamics. Hybrid approaches that combine both models are feasible and necessary for projects that aim to experimentally address synchronicity.
文摘Synchronicity involves the experience of personal meaning entangled with ambiguous coincidences in time. Ambiguity results from incomplete information about the chances of various events occurring. The problem that this study addresses is the lack of empirical research on synchronicity. This study sought to address this problem by exploring the astrological hypothesis that planetary transits predict synchronicity events. Synchronicities were compared with the probability distributions of planetary transits. In comparison with the base rate prediction, planetary transits were not a significant predictor of synchronicity events. The findings of this study provide new insight into the complex, multifaceted, and ambiguous phenomenon of synchronicity. The concept of ambiguity tolerance plays a significant role in synchronicity research since ambiguity cannot be completely eliminated.
文摘In this work we analyze the concept of time dilation in its application to the rate of moving clocks. The rates of two equiform elementary electromagnetic clocks of different orientations relative to their direction of motion are computed on the basis of relativistic transformations of force and coordinates for the case when the clocks are at rest in a stationary reference frame and for the case when they are moving at constant speed relative to the stationary reference frame. It is shown that, although both clocks run slower when they are moving than when they are at rest, the rate of the moving clocks is affected by their orientation relative to their direction of motion, rather than by the kinematic (relativistic) time dilation as it is now generally assumed. The implication of this result for the experimental proofs of the existence of the kinematic the dilation is discussed.
文摘Objectives To quantitatively analyze the longitudinal myocardial systolic and diastolic velocities and time intervals of the left ventricle in normal subjects, and to explore the value of pulsed Doppler tissue imaging （DTI） for the assessment of left ventricular systolic and diastolic synchronicity. Methods Twenty and six healthy subjects were studied by pulsed DTI. The septal and lateral, anterior and inferior walls of the left ventricle were displayed respectively, and basal and middle segments of each wall were selected for myocardial motion spectrum sampling. DTI parameters were： peak systolic myocardial velocity （s）, regional pre-ejection period （PEP）, time to the peak of s wave （Ts）, regional ejection time （ET） ; peak early diastolic velocity （e）, peak late diastolic velocity （a）, e/a ratio, time to the beginning of e wave （QE）, time to the peak of e wave （Te） and regional isovolumic relaxation time （IVRT）. Results The e and e/a were significantly different among basal segments, and s and e/a were significantly different among middle segments, with the highest value in lateral segments and the lowest value in septal segments. The s, e and a were all significantly higher in basal segments than middle segments. None of the systolic time intervals （PEP, Ts and ET） and diastolic time intervals （QE, Te and IVRT） were significantly different among basal segments and middle segments, neither were they when basal segment was compared with middle segment. Conclusions In normal subjects, the longitudinal myocardial systolic and diastolic velocities of the left ventricle are not homogeneous, but the contraction and relaxation are highly synchronized. Pulsed DTI can be used to quantitatively analyze the systolic and diastolic synchronicity of the heart.
文摘Background Using tissue Doppler imaging and conventional echocardiographic technique, we examined the cardiac function and synchronicity in individuals with isolated right bundle branch block （RBBB） or left bundle branch block （LBBB） and assessed the relationship between QRS duration and synchronicity.
文摘Background Mechanical asynchrony is an important parameter in predicting the response to cardiac resynchronization therapy, but detailed knowledge about cardiac timing in healthy persons is scarce. Therefore, in the current study, we sought to investigate the physiological status of interventricular synchronicity using pulse wave flow and tissue Doppler imaging in a healthy Chinese population. Methods Eighty-eight healthy volunteers underwent standard flow and tissue Doppler echocardiographic examinations. Ventricular inflow and outflow pulse wave flow Doppler patterns were recorded together with annulus pulse tissue Doppler imaging. Time intervals from the beginning of the QRS complex to the onset, peak and end of each wave were measured. Results The onsets of systole between left and right ventricles were highly synchronized by both imaging modalities. However, the left ventricle reached the peak flow ejection and peak mechanical contraction earlier than the right ventricle, （165.61±26.23） ms vs. （204.3±34.55） ms （P 〈0.01） and （133.62±26.19） ms vs. （191.25±38.47） ms （P 〈0.01）. Time to peak early diastolic relaxation was earlier in the left ventricle than in the right heart, （500.23±56.52） ms vs. （524.94±47.42） ms （P 〈0.01 ）. Conclusions Left and right ventricles were well synchronized at the onsets of systole and diastole even though interventricular peak systolic and peak early diastolic dyssynchrony was observed in healthy people by pulse wave Doppler imaging. In addition, diastolic timing events were slightly affected by age and gender.
基金Supported by National Natural Science Foundation of China(No.71902183).
文摘We analyze whether product market advertising has a spillover effect on stock price synchronicity by transmitting firm-specific information to the capital market and attracting more investor attention.Using a sample of Chinese listed firms from 2009 to 2017,we find that firms with greater advertising expenditures have lower stock price synchronicity.The results are robust after we address endogeneity concerns.In accord with our hypothesis that product market advertising increases the amount of firm-level information capitalized into stock prices through the information channel,we find that the impact of advertising on synchronicity is more pronounced for firms with a higher degree of information asymmetry and firms in the consumer-product industry.Further tests show that product market advertising enhances the ability of current period returns to reflect future earnings,and thus rules out that the negative relationship between advertising and synchronicity is driven by noise trading.Our results imply that product market advertising plays an informative role and improves information efficiency in a capital market.
文摘Based on a sample of Chinese A-share listed firms from 2015 to 2018,this paper studies the impact of annual report comment letters(ARCLs)on firm stock price synchronicity.We find that after firms receive ARCLs,their stock price synchronicity decreases.Moreover,the longer the ARCLs and the more negative the ARCLs’tone,the lower the resulting stock price synchronicity.The mechanism test shows that after firms receive ARCLs,the firms’information disclosure increases in quantity and quality,external media attention increases,and the firms’governance improves,reducing their stock price synchronicity.Further research shows that this negative association is more significant in firms with higher information asymmetry.This paper shows that the ARCL,an innovative application of the capital market supervision philosophy,is conducive to improving the quality of listed firms and to the healthy development of the capital market.
文摘We designed and investigated a passive synchronized mode-locked fiber laser.The device utilizes a dual-cavity structure driven by the nonlinear polarization rotation(NPR)mechanism.Stable mode-locking is attained by synergistically controlling gain,polarization state,and optical path length in two symmetric sub-cavities.Experiments proved that repetition rate of the sub-cavities can be adjusted via the time delay line(TDL)to achieve synchronized mode-locking.The system stably generates multi-wavelength pulses at a single repetition frequency,evidenced by multiple spectral peaks and equidistant pulse sequences.These findings facilitate the development of high-performance multi-wavelength ultrashort pulse sources,crucial for optical communications,spectral analysis,and remote sensing.
文摘Lip synchronization serves as a core technology for enabling natural interactions in digital virtual humans.However,it faces challenges such as insufficient dynamic correspondence between speech and lip movements and inadequate modeling of image details.To address these limitations,a comprehensively optimized lip synchronization framework extending the Wav2Lip architecture was proposed in this study.Firstly,based on the Wav2Lip model,a facial region extraction strategy using facial keypoints was designed,which effectively enhances the robustness of facial alignment during lip synchronization for digital virtual humans.Then,a cross-modal attention fusion module between visual and speech features was introduced to improve cross-modal information fusion,and a dynamic receptive field convolution module was developed in the generation branch to enhance the modeling performance of the lip region.Finally,experiments were conducted on the VFHQ dataset.The proposed method was compared with Wav2Lip,VideoRetalking,and DI-Net models,and its performance was evaluated using three metrics:LSE-C,CSIM,and FID.Experimental results showed that the proposed method achieves significant improvements in synchronization accuracy and image fidelity,providing an efficient and feasible solution for lip-synthesis tasks of digital virtual humans.
基金Supported by NSFC (No.12401024)the Scientific Research Innovation Project of Lingnan Normal University (Nos.LT2401,LT2410)。
文摘Let T_(n) and S_(n) be the full transformation semigroup and the symmetric group on X_(n)={1,2,...,n},respectively.Let G be a transitiveimprimitive subgroupof S_(n) with nontrivial blocksΔand letαbe a transformation in T_(n)\S_(n).The kernel ofαis the partition of X_(n) induced by the equivalence relation{(x,y)|xα=yα};the kernel type ofαis the partition of n given by the sizes of the parts of the kernel.A transformation semigroup is called synchronizing if it contains a constant map.Then a group G synchronizes a transformationαif the semigroup(G,α)contains a constant map.In this paper,we study a transitive imprimitive permutation group G together with a non-invertible transformationαthat generate a synchronizing semigroup.We mainly discuss 7 cases where G synchronizes a special transformationαwith each kernel class A_(i)(A_(1)j)satisfying|A_(i)∩Δ|=1(|A_(1)j∩Δ|=1)for all blocksΔofG,that is,the kernel type ofαis(|A_(1)|,1,...,1),(|A_(1)1|,...,|A_(1m)|,|A_(2)|,...,|Ar|),or(|A_(1)|,...,|A_(t)|,1,...,1),or the rank is 2,3,4,or n-2.
基金support from the National Natural Science Foundation of China (Nos.72272098 and 71972131).
文摘This paper examines the impact on stock return synchronicity of information provided by people who neighbor firms.Neighboring people have inherent advantages in acquiring and interpreting information.We employed novel satellite nighttime light data as a proxy for information held by neighboring people.Our analyses confirmed that brighter nighttime light was related to greater and better-quality information production.Using a sample of 18,963 firm-year observations over the 2000-2013 period,we found that information from nearby people facilitated the incorporation of firm-specific information into stock prices,resulting in lower stock return synchronicity.The results were robust when using the slope as an instrumental variable and were supported by various sensitivity checks.The effect of nighttime light intensity was more pronounced for firms operating across multiple geographic regions or diverse industries,those situated near more parks and shopping malls,and those with fewer institutional investors and less media coverage.
基金supported by the National Natural Science Foundation of China (Grant No.12274131)the Innovation Program for Quantum Science and Technology (Grant No.2024ZD0300101)。
文摘Optical non-reciprocity is a fundamental phenomenon in photonics.It is crucial for developing devices that rely on directional signal control,such as optical isolators and circulators.However,most research in this field has focused on systems in equilibrium or steady states.In this work,we demonstrate a room-temperature Rydberg atomic platform where the unidirectional propagation of light acts as a switch to mediate time-crystalline-like collective oscillations through atomic synchronization.
基金funded by State Grid Corporation of China,grant number DQ30DK24001L。
文摘When the converter bus voltage of a voltage source converter-based high voltage direct current(VSC-HVDC)system drops below a certain predetermined threshold,the system enters low-voltage ride-through(LVRT)mode to avoid overcurrent and potential equipment failure,during which it operates as a controlled current source.The influence mechanism of LVRT control strategies on short-circuit current and overall system stability remains not yet fully and systematically investigated.First,this paper provides an overview of several LVRT strategies for VSC-HVDC systems and examines their effects on short-circuit current contribution.Next,it analyzes in detail the mechanisms through which active and reactive currents injected during LVRT impact system frequency stability,voltage stability,and synchronization stability.To address these interrelated issues,an optimized and comprehensive LVRT strategy incorporating short-circuit current constraints is proposed.The approach determines the active current ratio based on system frequency stability requirements and dynamically adjusts the active current recovery rate via phase control of the VSC-HVDC bus.The remaining capacity is allocated to reactive current support,thereby enhancing voltage and synchronization stability while maintaining sufficient short-circuit current margin and system frequency stability.Finally,simulations conducted on the PSS/E platform,using actual grid data from a selected cross-section system,validate convincingly the effectiveness of the proposed parameter optimization strategy for VSC-HVDC low-voltage ride-through.
基金supported by the Science and Technology Project of State Grid Corporation of China(5400-202199281A-0-0-00).
文摘In a multiple voltage source converter(VSC)system,the nonlinear characteristics of phase-locked loops(PLLs)and their interactions have a significant influence on the synchronization stability of converters.In this paper,these influences are investigated from the perspective of the time domain.First,a novel time-domain model of the multi-VSC system is obtained by using a multi-scale method.On this basis,a stability criterion is proposed to assess the synchronization stability of the system.Then,the accuracy of the time-domain model and its stability criterion in various conditions are discussed.Moreover,the negative impact of the interaction on the system is quantified.Finally,the above theoretical analysis is also verified in the controller hardware-in-the-loop(CHIL)experiments.
基金supported by the National Natural Science Foundation of China(62373317)the Tianshan Talent Training Program(2022TSYCCX0013)+3 种基金the Key Project of Natural Science Foundation of Xinjiang(2021D01D10)the Basic Research Foundation for Universities of Xinjiang(XJEDU2023P023)the Xinjiang Key Laboratory of Applied Mathematics(XJDX1401)the Intelligent Control and Optimization Research Platform in Xinjiang University.
文摘This paper is dedicated to fixed-time passivity and synchronization for multi-weighted spatiotemporal directed networks.First,to achieve fixed-time passivity,a type of decentralized power-law controller is developed,in which only one parameter needs to be adjusted in the power-law terms;this greatly decreases the inconvenience of parameter adjustment.Second,several fixed-time passivity criteria with LMI forms are derived by using a Gauss divergence theorem to deal with the spatial diffusion of nodes and by applying the Hölder’s inequality to dispose rigorously the power-law term greater than one in the designed control scheme;this improves the previous theoretical analysis.Additionally,the fixed-time synchronization of spatiotemporal directed networks with multi-weights is addressed as a direct result of fixed-time strict passivity.Finally,a numerical example is presented in order to show the validity of the theoretical analysis.
文摘Modern/distributed electric energy systems,with ever larger penetration of renewable(photovoltaic,wind,wave,and hydro)energy sources and time-variable outputs,are in need of stronger/higher frequency and alternating current(AC)(direct current(DC))voltage control.In fact,faster and more stable active and reactive power in the presence of frequency and voltage sags and swells is needed.Power electronics-controlled variable speed generators do not have enough energy storage(inertia)for the scope(static synchronous compensators(STATCOMs)included).This is because power electronics tends to decouple the generator from the power system.While virtual inertia control in doubly fed induction generators(DFIGs)offers a partial solution to these problems,a more robust and comprehensive framework is required for advanced grid support.This is how,by extending the dual-excitation principles,the dualaxis excited electric synchronous generators(DE-SG)provide superior flexibility in two variants summarized here:as a multifunctional DFIG and dual-axis vs.single-axis excited synchronous generator(SG),and as a synchronous condenser(SC),with dual DC and AC excitation(as a no-load DFIG with inertia wheel),where variable speed is used to accelerate/decelerate the SC and thus provide additional assistance in frequency stabilization.These solutions,good for short-time transients,are not meant,however,to replace the large bidirectional energy storage systems(pump-hydro,hydrogen,batteries,etc.)which are crucial for the daily inherent variations of output energy in modern power systems with multiple power sources.The present paper offers a summary of techniques used in the dual-axis excited vs.single-axis excited SGs(SE-SGs),and SCs topologies,modeling,and control for better stability in modern multiple-source energy systems.This survey includes multiple case studies to shed light on prominent methods.
