Raman spectroscopy offers a great power to detect,analyze and identify molecules,and monitor their temporal dynamics and evolution when combined with single-molecule surface-enhanced Raman scattering(SM-SERS)substrate...Raman spectroscopy offers a great power to detect,analyze and identify molecules,and monitor their temporal dynamics and evolution when combined with single-molecule surface-enhanced Raman scattering(SM-SERS)substrates.Here we present a SM-SERS scheme that involves simultaneously giant chemical enhancement from WS22D materials,giant electromagnetic enhancement from plasmonic nanogap hot spot,and inhibition of molecular fluorescence influence under near-infrared laser illumination.Remarkably we find Coulomb attraction between analyte and gold nanoparticle can trigger spontaneous formation of molecule-hotspot pairing with high precision,stability and robustness.The scheme has enabled realization of universal,robust,fast,and large-scale uniform SM-SERS detection for three Raman molecules of rhodamine B,rhodamine 6G,and crystal violet with a very low detection limit of 10−16 M and at a very fast spectrum acquisition time of 50 ms.展开更多
The measurement of the pairing gap is crucial for investigating the physical properties of superconductors or superfluids.We propose a strategy to measure the pairing gap through the dynamical excitations.With the ran...The measurement of the pairing gap is crucial for investigating the physical properties of superconductors or superfluids.We propose a strategy to measure the pairing gap through the dynamical excitations.With the random phase approximation(RPA),we study the dynamical excitations of a two-dimensional attractive Fermi-Hubbard model by calculating its dynamical structure factor.Two distinct collective modes emerge:a Goldstone phonon mode at transferred momentum q=[0,0]and a roton mode at q=[p,p].The roton mode exhibits a sharp molecular peak in the low-energy regime.Notably,the area under the roton molecular peak scales with the square of the pairing gap,which holds even in three-dimensional and spin-orbit coupled(SOC)optical lattices.This finding suggests an experimental approach to measure the pairing gap in lattice systems by analyzing the dynamical structure factor at q=[p,p].展开更多
Dynamical systems often exhibit multiple attractors representing significantly different functioning conditions.A global map of attraction basins can offer valuable guidance for stabilizing or transitioning system sta...Dynamical systems often exhibit multiple attractors representing significantly different functioning conditions.A global map of attraction basins can offer valuable guidance for stabilizing or transitioning system states.Such a map can be constructed without prior system knowledge by identifying attractors across a sufficient number of points in the state space.However,determining the attractor for each initial state can be a laborious task.Here,we tackle the challenge of reconstructing attraction basins using as few initial points as possible.In each iteration of our approach,informative points are selected through random seeding and are driven along the current classification boundary,promoting the eventual selection of points that are both diverse and enlightening.The results across various experimental dynamical systems demonstrate that our approach requires fewer points than baseline methods while achieving comparable mapping accuracy.Additionally,the reconstructed map allows us to accurately estimate the minimum escape distance required to transition the system state to a target basin.展开更多
The search for photoactive materials that are able to efficiently produce solar fuels is a growing research field to tackle the current energy crisis.Herein,we have prepared two ionic non-noble metallo-supramolecular ...The search for photoactive materials that are able to efficiently produce solar fuels is a growing research field to tackle the current energy crisis.Herein,we have prepared two ionic non-noble metallo-supramolecular polymers Se-MTpy(M=Co or Ni),and constructed their composites with single-walled carbon nanotubes(CNTs)via electrostatic attraction andπ-πinteractions for efficient and stable photocatalytic hydrogen evolution.In the photocatalytic system,the cationic Se-MTpy as host and anionic CNTs as vip are assembled into a binary composite,which exhibits superior photocatalytic activity under visible light irradiation(>420 nm).The optimized CNT@Se-CoTpy composite,containing 1.2 wt%metal loading,achieves 7 times higher hydrogen evolution rate(2.47 mmol g^(-1)h^(-1))than bare Se-CoTpy(0.35 mmol g^(-1)h^(-1)).This is attributed to the constructive formation of junctions between polymer and CNTs,facilitating interfacial charge transfer and transport for efficient proton reduction.The composite system also shows high photostability after continuous irradiation for~30 h.The combination of experimental and theoretical analysis demonstrates the higher activity for reducing H_(2)O to H_(2)of Se-CoTpy than Se-NiTpy.The feasible interfacial architecture proposed in this study represents an effective approach to achieve high photocatalytic performance.展开更多
In order to improve the competitiveness of smart tourist attractions in the tourism market,this paper selects a scenic spot in Shenyang and uses big data technology to predict the passenger flow of the scenic spot.Fir...In order to improve the competitiveness of smart tourist attractions in the tourism market,this paper selects a scenic spot in Shenyang and uses big data technology to predict the passenger flow of the scenic spot.Firstly,this paper introduces the big data-driven forecast model of scenic spot passenger flow.Based on the traditional autoregressive integral moving average model and artificial neural network model,it builds a big data analysis and forecast model.Through the analysis of data source,model building,scenic spot passenger flow accuracy,and modeling time comparison,it affirms the advantages of big data analysis in forecasting scenic spot passenger flow.Finally,it puts forward four commercial operation optimization strategies:adjusting the ticket pricing of scenic spots,upgrading the catering and accommodation services in scenic spots,planning and designing play projects,and formulating accurate scenic spot marketing strategies,in order to provide references for the optimization and upgrading of smart tourist attractions in the future.展开更多
The development of nanomedicine that can be efficiently internalized by drug-resistant cancer cells still presents a daunting challenge due to the low uptake capacity caused by various drug resistance-related factors ...The development of nanomedicine that can be efficiently internalized by drug-resistant cancer cells still presents a daunting challenge due to the low uptake capacity caused by various drug resistance-related factors on the cell membrane.Herein,we engineered the surfaces of glycan nanocarriers with negative,neutral,and gradient positive charges,and discovered that positively charged nanocarriers can be anchored onto the cell membrane through electrostatic attraction and thus be efficiently internalized by drug-resistant cancer cells.In contrast,drug-resistant cancer cells do not readily uptake neutral or negatively charged nanocarriers.By proposing a concentric ring fluorescence coefficient(CRFC),we were able to quantify the cell membrane anchoring capabilities of the nanocarriers and found that positively charged nanocarriers have a much stronger anchoring ability toward drug-resistant cell membranes than their neutral and negatively charged counterparts.Interestingly,with the increase of positive charge,the ability of the nanocarriers to become anchored onto cell membranes was further enhanced,thus confirming that electrostatic attraction plays a crucial role in the membrane-anchoring guided cellular uptake.The method of endowing nano-objects with this charge-attracting capability towards negatively charged cell membranes to drive membrane-anchoring mediated cellular uptake illustrates its potential as a universal strategy for engineering nanocarriers to promote the uptake of nanodrugs into drug-resistant cancer cells and thus improve the therapeutic effect.展开更多
Through analyzing relevant documents,connotations of rural landscape attractiveness were introduced,and existing problems of present rural landscapes elaborated.It was proposed that rural tourism of China has no effec...Through analyzing relevant documents,connotations of rural landscape attractiveness were introduced,and existing problems of present rural landscapes elaborated.It was proposed that rural tourism of China has no effective strategic planning,distinctive characteristics of landscape products,or efficient marketing of rural landscape resources.Influencing factors of rural landscape attractiveness were summarized,and suggestions were given to improve the attractiveness by combining with actual conditions of China.Moreover,it was stressed that favorable rural landscape images should be created,and more efforts devoted in safeguarding native-soil cultural landscapes and exploring tourist market of rural landscape resources.The study was to provide useful references for the new countryside construction of China.展开更多
Enormous progresses to understand the jamming transition have been driven via simulating purely repulsive particles which were somehow idealized in the past two decades. While the attractive systems are both theoretic...Enormous progresses to understand the jamming transition have been driven via simulating purely repulsive particles which were somehow idealized in the past two decades. While the attractive systems are both theoretical and practical compared with repulsive systems. By studying the statistics of rigid clusters, we find that the critical packing fraction φ_(c) varies linearly with attraction μ for different system sizes when the range of attraction is short. While for systems with long-range attractions, however, the slope of φ_(c) appears significantly different, which means that there are two distinct jamming scenarios. In this paper, we focus our main attention on short-range attractions scenario and define a new quantity named "short-range attraction susceptibility" χ_(p), which describes the degree of response of the probability of finding jammed states pjto short-range attraction strength μ. Our central results are that χ_(p) diverges in the thermodynamic limit as χ_(p) ∝|φ-φ_(c)^(∞)|^(-γ_(p)), where φ_(c)^(∞) is the packing fraction at the jamming transition for the infinite system in the absence of attraction. χ_(p) obeys scaling collapse with a scaling function in both two and three dimensions, illuminating that the jamming transition can be considered as a phase transition as proposed in previous work.展开更多
[Objective] The paper aims to study the attractive effects of 12 Chinese medicinal herbs on Scophthalmus maximus juvenile.[Method] We took 200 Scophthalmus maximus with the average body length of 3 cm,average weight o...[Objective] The paper aims to study the attractive effects of 12 Chinese medicinal herbs on Scophthalmus maximus juvenile.[Method] We took 200 Scophthalmus maximus with the average body length of 3 cm,average weight of 1 g and 60 days of age as the research object,and 12 Chinese medicinal herbs as feed attractants were selected,including Cloves,Cinnamon,Star anise,Kaempferol,Mint,Coptis,Phellodendron,skullcap,Gardenia,Sophora flavescens,Mume,Myrobalan meat were selected.The amount added to the basic diet was 2‰..The times of turbot juveniles going into each inducing room and the times of turbot juveniles biting the feed ball were recorded by maze experiments.Inducing effects of the Chinese herbal medicines were analyzed.[Result] The results showed that the attractant effect of Mume,Gardenia,Scutellaria and kaempferol had the significantly inducing effect on Scophthalmus maximus juvenile.And 2‰ Gardenia,5‰ Matrine,5‰ Scutellaria and 2‰ Kaempferol have the best attractant effects.In compound experients,the attractive effect of mixture of 2‰ matrine and gardenia on Scophthalmus maximus was the best.[Conclusion] The attractive effect on Scophthalmus maximus has something to do with the kind and concentration of Chinese medicinal herbs.展开更多
Modeling research and empirical study on the attraction of tourism destinations were conducted from 6 aspects,i.e.quality and scale of tourism resources,economic environment of tourism destinations,policy environment,...Modeling research and empirical study on the attraction of tourism destinations were conducted from 6 aspects,i.e.quality and scale of tourism resources,economic environment of tourism destinations,policy environment,accessibility,income level of tourist source areas as well as distance between tourist source area and tourism destination.展开更多
Several new sufficient conditions are given for the global attractivity of solutions of a kind of delay difference equations. They either include or improve some known results and put the study of Ladas' conjectur...Several new sufficient conditions are given for the global attractivity of solutions of a kind of delay difference equations. They either include or improve some known results and put the study of Ladas' conjecture forward.展开更多
Through survey of visitors,relevant data had been acquired.By aid of factor analysis method,computation model of comprehensive tourist attractiveness of ancient villages and towns was established,which had certain the...Through survey of visitors,relevant data had been acquired.By aid of factor analysis method,computation model of comprehensive tourist attractiveness of ancient villages and towns was established,which had certain theoretical and practical guidance value to rural tourism resources development and market development.展开更多
In order to improve the management level of heritage tourist attractions and achieve their sustainable development,a comparative study has been conducted on the management mode of heritage tourist attractions in China...In order to improve the management level of heritage tourist attractions and achieve their sustainable development,a comparative study has been conducted on the management mode of heritage tourist attractions in China and foreign countries from the perspective of management foundation,management objects and management resources.Then,suggestions have been proposed from the ideology and supervision mechanism,including improving ideology,upgrading management system,completing supervision mechanism and adopting international management mode.Particularly,the paper has pointed out that it should find the best management mode based on different social and economic backgrounds of the countries of heritage tourist attractions.展开更多
The dynamic behavior of discrete-time cellular neural networks(DTCNN), which is strict with zero threshold value, is mainly studied in asynchronous mode and in synchronous mode. In general, a k-attractor of DTCNN is n...The dynamic behavior of discrete-time cellular neural networks(DTCNN), which is strict with zero threshold value, is mainly studied in asynchronous mode and in synchronous mode. In general, a k-attractor of DTCNN is not a convergent point. But in this paper, it is proved that a k-attractor is a convergent point if the strict DTCNN satisfies some conditions. The attraction basin of the strict DTCNN is studied, one example is given to illustrate the previous conclusions to be wrong, and several results are presented. The obtained results on k-attractor and attraction basin not only correct the previous results, but also provide a theoretical foundation of performance analysis and new applications of the DTCNN.展开更多
To improve the complexity of chaotic signals,in this paper we first put forward a new three-dimensional quadratic fractional-order multi-scroll hidden chaotic system,then we use the Adomian decomposition algorithm to ...To improve the complexity of chaotic signals,in this paper we first put forward a new three-dimensional quadratic fractional-order multi-scroll hidden chaotic system,then we use the Adomian decomposition algorithm to solve the proposed fractional-order chaotic system and obtain the chaotic phase diagrams of different orders,as well as the Lyaponov exponent spectrum,bifurcation diagram,and SE complexity of the 0.99-order system.In the process of analyzing the system,we find that the system possesses the dynamic behaviors of hidden attractors and hidden bifurcations.Next,we also propose a method of using the Lyapunov exponents to describe the basins of attraction of the chaotic system in the matlab environment for the first time,and obtain the basins of attraction under different order conditions.Finally,we construct an analog circuit system of the fractional-order chaotic system by using an equivalent circuit module of the fractional-order integral operators,thus realizing the 0.9-order multi-scroll hidden chaotic attractors.展开更多
This work studies the stability and hidden dynamics of the nonlinear hydro-turbine governing system with an output limiting link,and propose a new six-dimensional system,which exhibits some hidden attractors.The param...This work studies the stability and hidden dynamics of the nonlinear hydro-turbine governing system with an output limiting link,and propose a new six-dimensional system,which exhibits some hidden attractors.The parameter switching algorithm is used to numerically study the dynamic behaviors of the system.Moreover,it is investigated that for some parameters the system with a stable equilibrium point can generate strange hidden attractors.A self-excited attractor with the change of its parameters is also recognized.In addition,numerical simulations are carried out to analyze the dynamic behaviors of the proposed system by using the Lyapunov exponent spectra,Lyapunov dimensions,bifurcation diagrams,phase space orbits,and basins of attraction.Consequently,the findings in this work show that the basins of hidden attractors are tiny for which the standard computational procedure for localization is unavailable.These simulation results are conducive to better understanding of hidden chaotic attractors in higher-dimensional dynamical systems,and are also of great significance in revealing chaotic oscillations such as uncontrolled speed adjustment in the operation of hydropower station due to small changes of initial values.展开更多
In this paper, we provide a new approach to study the geometry of attractor. By applying category, we investigate the relationship between attractor and its attraction basin. In a complete metric space, we prove that ...In this paper, we provide a new approach to study the geometry of attractor. By applying category, we investigate the relationship between attractor and its attraction basin. In a complete metric space, we prove that the categories of attractor and its attraction basin are always equal. Then we apply this result to both autonomous and non-autonomous systems, and obtain a number of corresponding results.展开更多
Arthur Miller's masterpiece Death of a Salesman is a very clear attack on the American success myth.The most dominant theme running throughout the play is Willy Loman's philosophy of personal attractiveness an...Arthur Miller's masterpiece Death of a Salesman is a very clear attack on the American success myth.The most dominant theme running throughout the play is Willy Loman's philosophy of personal attractiveness and its doomed futility.This philosophy not only brings failure to Willy's career but also destruction to Willy's family members.展开更多
Spatial equity in access to urban services is a significant element of sustainable urban planning.To date,a service-based index is used to measure service attractiveness,considering attractiveness as a static concept....Spatial equity in access to urban services is a significant element of sustainable urban planning.To date,a service-based index is used to measure service attractiveness,considering attractiveness as a static concept.While from the user side view,service attractiveness is a dynamic concept related to the variation of different opportunities of users to use the services and capacities.In this paper,a user-based method for measuring service attractiveness is proposed.In this approach,the attractiveness of service for a user is modeled as a function of the user's Travel Times(TT),Free Times(FTs),park size and relative positions of the user,local demanding population,and service.Then,the inequity of attractiveness of services for different users has been examined using three inequity indices including the Duration of Use(DU),Frequency of Visit(FV),and the Chance of Space Choice(CSC).The proposed method is applied to urban regional parks of Tehran municipality.Traffc Analysis Zones(TAZs)and regional parks are respectively regarded as the users and services.In addition to considering inequity of access to the first closest park,the additional cost of accessing to the other two closest parks is also considered.Results show that the proposed method leads to the exploration of the existing inequities of DU,FV,and CSC among residents in local scales,whereas in the service-based method,all users of a service are highlighted with a single value of attractiveness.Comparison of the user-based and service-based attractiveness indices show significant differences.As an example,user-based attractiveness values of about 14%and 20%of TAZs are respectively 5 and 3 square meters more than that of the service-based attractiveness index.However,the service-based method is suitable for regional-scale comparison of the inequities.Therefore,the proposed index can complement the service-based index for inequity mapping and management in varying scales.展开更多
The multicolored Asian lady beetle, Harmonia axyridis(Coleoptera: Coccinellidae), is a common generalist predator in China and is occasionally found gathering on the Chinese pagoda tree, Sophora japonica, in summer. I...The multicolored Asian lady beetle, Harmonia axyridis(Coleoptera: Coccinellidae), is a common generalist predator in China and is occasionally found gathering on the Chinese pagoda tree, Sophora japonica, in summer. In a field investigation, we found that H. axyridis adults preferred S. japonica during its flowering period even though their optimal prey(aphid) is absent at this time. In addition, male and female adults were attracted to S. japonica flowers to a similar extent in a Y-tube olfactometer assay. Using coupled gas chromatography-electroantennogram detection(GC-EAD), we identified a flower odor component(nonanal) that elicited a significant electrophysiological response in H. axyridis. Electroantennogram(EAG) dose-dependent responses revealed that the amplitude of the adult beetle's EAG response increased with increasing concentration of nonanal, peaking at 10 mg mL^(–1). In Y-tube olfactometer behavioral tests, H. axyridis adults preferred a 10 mg mL^(–1) nonanal source over a 100 mg mL^(–1) diluent. Under field conditions, the adults were significantly attracted to both concentrations(10 and 100 mg mL^(–1)), and high concentrations generally had greater attraction. All these results suggest that nonanal, a volatile compound of S. japonica flowers, greatly attracts H. axyridis adults. This study provides a basis for the development of synthetic attractants of H. axyridis, with the potential to promote biocontrol services of this generalist predator in the native area(e.g., China) and to suppress its population by mass trapping in its invasive areas.展开更多
基金financial support from Science and Technology Project of Guangdong(2020B010190001)National Natural Science Foundation(12434016).
文摘Raman spectroscopy offers a great power to detect,analyze and identify molecules,and monitor their temporal dynamics and evolution when combined with single-molecule surface-enhanced Raman scattering(SM-SERS)substrates.Here we present a SM-SERS scheme that involves simultaneously giant chemical enhancement from WS22D materials,giant electromagnetic enhancement from plasmonic nanogap hot spot,and inhibition of molecular fluorescence influence under near-infrared laser illumination.Remarkably we find Coulomb attraction between analyte and gold nanoparticle can trigger spontaneous formation of molecule-hotspot pairing with high precision,stability and robustness.The scheme has enabled realization of universal,robust,fast,and large-scale uniform SM-SERS detection for three Raman molecules of rhodamine B,rhodamine 6G,and crystal violet with a very low detection limit of 10−16 M and at a very fast spectrum acquisition time of 50 ms.
基金supported by the National Natural Science Foundation of China[Grant Nos.U23A2073(P.Z.)and 11547034(H.Z.)].
文摘The measurement of the pairing gap is crucial for investigating the physical properties of superconductors or superfluids.We propose a strategy to measure the pairing gap through the dynamical excitations.With the random phase approximation(RPA),we study the dynamical excitations of a two-dimensional attractive Fermi-Hubbard model by calculating its dynamical structure factor.Two distinct collective modes emerge:a Goldstone phonon mode at transferred momentum q=[0,0]and a roton mode at q=[p,p].The roton mode exhibits a sharp molecular peak in the low-energy regime.Notably,the area under the roton molecular peak scales with the square of the pairing gap,which holds even in three-dimensional and spin-orbit coupled(SOC)optical lattices.This finding suggests an experimental approach to measure the pairing gap in lattice systems by analyzing the dynamical structure factor at q=[p,p].
基金supported by the National Natural Science Foundation of China(Grant Nos.T2225022,12350710786,62088101,and 12161141016)Shuguang Program of Shanghai Education Development Foundation(Grant No.22SG21)Shanghai Municipal Education Commission,and the Fundamental Research Funds for the Central Universities。
文摘Dynamical systems often exhibit multiple attractors representing significantly different functioning conditions.A global map of attraction basins can offer valuable guidance for stabilizing or transitioning system states.Such a map can be constructed without prior system knowledge by identifying attractors across a sufficient number of points in the state space.However,determining the attractor for each initial state can be a laborious task.Here,we tackle the challenge of reconstructing attraction basins using as few initial points as possible.In each iteration of our approach,informative points are selected through random seeding and are driven along the current classification boundary,promoting the eventual selection of points that are both diverse and enlightening.The results across various experimental dynamical systems demonstrate that our approach requires fewer points than baseline methods while achieving comparable mapping accuracy.Additionally,the reconstructed map allows us to accurately estimate the minimum escape distance required to transition the system state to a target basin.
基金supported by the RGC Senior Research Fellowship Scheme(Grant No.SRFS2021-5S01)the Hong Kong Research Grants Council(Grant No.PolyU 15307321)+2 种基金Research Institute for Smart Energy(CDAQ),Research Centre for Nanoscience and Nanotechnology(CE2H),Research Centre for Carbon-Strategic Catalysis(CE2L)Miss Clarea Au for the Endowed Professorship in Energy(Grant No.847S)National Natural Science Foundation of China(Grant No.62205277).
文摘The search for photoactive materials that are able to efficiently produce solar fuels is a growing research field to tackle the current energy crisis.Herein,we have prepared two ionic non-noble metallo-supramolecular polymers Se-MTpy(M=Co or Ni),and constructed their composites with single-walled carbon nanotubes(CNTs)via electrostatic attraction andπ-πinteractions for efficient and stable photocatalytic hydrogen evolution.In the photocatalytic system,the cationic Se-MTpy as host and anionic CNTs as vip are assembled into a binary composite,which exhibits superior photocatalytic activity under visible light irradiation(>420 nm).The optimized CNT@Se-CoTpy composite,containing 1.2 wt%metal loading,achieves 7 times higher hydrogen evolution rate(2.47 mmol g^(-1)h^(-1))than bare Se-CoTpy(0.35 mmol g^(-1)h^(-1)).This is attributed to the constructive formation of junctions between polymer and CNTs,facilitating interfacial charge transfer and transport for efficient proton reduction.The composite system also shows high photostability after continuous irradiation for~30 h.The combination of experimental and theoretical analysis demonstrates the higher activity for reducing H_(2)O to H_(2)of Se-CoTpy than Se-NiTpy.The feasible interfacial architecture proposed in this study represents an effective approach to achieve high photocatalytic performance.
文摘In order to improve the competitiveness of smart tourist attractions in the tourism market,this paper selects a scenic spot in Shenyang and uses big data technology to predict the passenger flow of the scenic spot.Firstly,this paper introduces the big data-driven forecast model of scenic spot passenger flow.Based on the traditional autoregressive integral moving average model and artificial neural network model,it builds a big data analysis and forecast model.Through the analysis of data source,model building,scenic spot passenger flow accuracy,and modeling time comparison,it affirms the advantages of big data analysis in forecasting scenic spot passenger flow.Finally,it puts forward four commercial operation optimization strategies:adjusting the ticket pricing of scenic spots,upgrading the catering and accommodation services in scenic spots,planning and designing play projects,and formulating accurate scenic spot marketing strategies,in order to provide references for the optimization and upgrading of smart tourist attractions in the future.
基金the Shanghai Science and Technology Plan Project(No.25J22800600)the National Key R&D Program of China(No.2022YFE0100600)+4 种基金the National Natural Science Foundation of China(No.21871180)the Tracking Program for Professor of Special Appointment(Eastern Scholar)at the Shanghai Institutions of Higher Learning(No.SHDP201802)the Open Project of Translational Medicine of Shanghai Jiao Tong University(Nos.TMSK-2021-108,and TMSK-2021-305)STAR Program of Shanghai Jiao Tong University(No.20240303)Shanghai Jiao Tong University 2030 Initiative.The authors also wish to thank the Instrumental Analysis Center(IAC)at Shanghai Jiao Tong University for providing measurements to support our experiments.
文摘The development of nanomedicine that can be efficiently internalized by drug-resistant cancer cells still presents a daunting challenge due to the low uptake capacity caused by various drug resistance-related factors on the cell membrane.Herein,we engineered the surfaces of glycan nanocarriers with negative,neutral,and gradient positive charges,and discovered that positively charged nanocarriers can be anchored onto the cell membrane through electrostatic attraction and thus be efficiently internalized by drug-resistant cancer cells.In contrast,drug-resistant cancer cells do not readily uptake neutral or negatively charged nanocarriers.By proposing a concentric ring fluorescence coefficient(CRFC),we were able to quantify the cell membrane anchoring capabilities of the nanocarriers and found that positively charged nanocarriers have a much stronger anchoring ability toward drug-resistant cell membranes than their neutral and negatively charged counterparts.Interestingly,with the increase of positive charge,the ability of the nanocarriers to become anchored onto cell membranes was further enhanced,thus confirming that electrostatic attraction plays a crucial role in the membrane-anchoring guided cellular uptake.The method of endowing nano-objects with this charge-attracting capability towards negatively charged cell membranes to drive membrane-anchoring mediated cellular uptake illustrates its potential as a universal strategy for engineering nanocarriers to promote the uptake of nanodrugs into drug-resistant cancer cells and thus improve the therapeutic effect.
文摘Through analyzing relevant documents,connotations of rural landscape attractiveness were introduced,and existing problems of present rural landscapes elaborated.It was proposed that rural tourism of China has no effective strategic planning,distinctive characteristics of landscape products,or efficient marketing of rural landscape resources.Influencing factors of rural landscape attractiveness were summarized,and suggestions were given to improve the attractiveness by combining with actual conditions of China.Moreover,it was stressed that favorable rural landscape images should be created,and more efforts devoted in safeguarding native-soil cultural landscapes and exploring tourist market of rural landscape resources.The study was to provide useful references for the new countryside construction of China.
基金supported by the National Natural Science Foundation of China (Grant No. 11702289)Key Core Technology and Generic Technology Research and Development Project of Shanxi Province,China (Grant No. 2020XXX013)the National Key Research and Development Project of China。
文摘Enormous progresses to understand the jamming transition have been driven via simulating purely repulsive particles which were somehow idealized in the past two decades. While the attractive systems are both theoretical and practical compared with repulsive systems. By studying the statistics of rigid clusters, we find that the critical packing fraction φ_(c) varies linearly with attraction μ for different system sizes when the range of attraction is short. While for systems with long-range attractions, however, the slope of φ_(c) appears significantly different, which means that there are two distinct jamming scenarios. In this paper, we focus our main attention on short-range attractions scenario and define a new quantity named "short-range attraction susceptibility" χ_(p), which describes the degree of response of the probability of finding jammed states pjto short-range attraction strength μ. Our central results are that χ_(p) diverges in the thermodynamic limit as χ_(p) ∝|φ-φ_(c)^(∞)|^(-γ_(p)), where φ_(c)^(∞) is the packing fraction at the jamming transition for the infinite system in the absence of attraction. χ_(p) obeys scaling collapse with a scaling function in both two and three dimensions, illuminating that the jamming transition can be considered as a phase transition as proposed in previous work.
文摘[Objective] The paper aims to study the attractive effects of 12 Chinese medicinal herbs on Scophthalmus maximus juvenile.[Method] We took 200 Scophthalmus maximus with the average body length of 3 cm,average weight of 1 g and 60 days of age as the research object,and 12 Chinese medicinal herbs as feed attractants were selected,including Cloves,Cinnamon,Star anise,Kaempferol,Mint,Coptis,Phellodendron,skullcap,Gardenia,Sophora flavescens,Mume,Myrobalan meat were selected.The amount added to the basic diet was 2‰..The times of turbot juveniles going into each inducing room and the times of turbot juveniles biting the feed ball were recorded by maze experiments.Inducing effects of the Chinese herbal medicines were analyzed.[Result] The results showed that the attractant effect of Mume,Gardenia,Scutellaria and kaempferol had the significantly inducing effect on Scophthalmus maximus juvenile.And 2‰ Gardenia,5‰ Matrine,5‰ Scutellaria and 2‰ Kaempferol have the best attractant effects.In compound experients,the attractive effect of mixture of 2‰ matrine and gardenia on Scophthalmus maximus was the best.[Conclusion] The attractive effect on Scophthalmus maximus has something to do with the kind and concentration of Chinese medicinal herbs.
文摘Modeling research and empirical study on the attraction of tourism destinations were conducted from 6 aspects,i.e.quality and scale of tourism resources,economic environment of tourism destinations,policy environment,accessibility,income level of tourist source areas as well as distance between tourist source area and tourism destination.
文摘Several new sufficient conditions are given for the global attractivity of solutions of a kind of delay difference equations. They either include or improve some known results and put the study of Ladas' conjecture forward.
基金Supported by Research Project of Guilin College of Aerospace Technology (X09S024)~~
文摘Through survey of visitors,relevant data had been acquired.By aid of factor analysis method,computation model of comprehensive tourist attractiveness of ancient villages and towns was established,which had certain theoretical and practical guidance value to rural tourism resources development and market development.
文摘In order to improve the management level of heritage tourist attractions and achieve their sustainable development,a comparative study has been conducted on the management mode of heritage tourist attractions in China and foreign countries from the perspective of management foundation,management objects and management resources.Then,suggestions have been proposed from the ideology and supervision mechanism,including improving ideology,upgrading management system,completing supervision mechanism and adopting international management mode.Particularly,the paper has pointed out that it should find the best management mode based on different social and economic backgrounds of the countries of heritage tourist attractions.
文摘The dynamic behavior of discrete-time cellular neural networks(DTCNN), which is strict with zero threshold value, is mainly studied in asynchronous mode and in synchronous mode. In general, a k-attractor of DTCNN is not a convergent point. But in this paper, it is proved that a k-attractor is a convergent point if the strict DTCNN satisfies some conditions. The attraction basin of the strict DTCNN is studied, one example is given to illustrate the previous conclusions to be wrong, and several results are presented. The obtained results on k-attractor and attraction basin not only correct the previous results, but also provide a theoretical foundation of performance analysis and new applications of the DTCNN.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61561022 and 61672226)。
文摘To improve the complexity of chaotic signals,in this paper we first put forward a new three-dimensional quadratic fractional-order multi-scroll hidden chaotic system,then we use the Adomian decomposition algorithm to solve the proposed fractional-order chaotic system and obtain the chaotic phase diagrams of different orders,as well as the Lyaponov exponent spectrum,bifurcation diagram,and SE complexity of the 0.99-order system.In the process of analyzing the system,we find that the system possesses the dynamic behaviors of hidden attractors and hidden bifurcations.Next,we also propose a method of using the Lyapunov exponents to describe the basins of attraction of the chaotic system in the matlab environment for the first time,and obtain the basins of attraction under different order conditions.Finally,we construct an analog circuit system of the fractional-order chaotic system by using an equivalent circuit module of the fractional-order integral operators,thus realizing the 0.9-order multi-scroll hidden chaotic attractors.
基金the Fundamental Research Funds for the Northwest A&F University(Grant No./Z1090220172)the Scientific Research Foundation of the Natural Science Foundation of Shaanxi Province,China(Grant No.2019JLP-24)+1 种基金the Shaanxi Province Innovation Talent Promotion PlanScience and Technology Innovation Team,China(Grant No.2020TD-025)the Water Conservancy Science and Technology Program of Shaanxi Province,China(Grant No.2018slkj-9)。
文摘This work studies the stability and hidden dynamics of the nonlinear hydro-turbine governing system with an output limiting link,and propose a new six-dimensional system,which exhibits some hidden attractors.The parameter switching algorithm is used to numerically study the dynamic behaviors of the system.Moreover,it is investigated that for some parameters the system with a stable equilibrium point can generate strange hidden attractors.A self-excited attractor with the change of its parameters is also recognized.In addition,numerical simulations are carried out to analyze the dynamic behaviors of the proposed system by using the Lyapunov exponent spectra,Lyapunov dimensions,bifurcation diagrams,phase space orbits,and basins of attraction.Consequently,the findings in this work show that the basins of hidden attractors are tiny for which the standard computational procedure for localization is unavailable.These simulation results are conducive to better understanding of hidden chaotic attractors in higher-dimensional dynamical systems,and are also of great significance in revealing chaotic oscillations such as uncontrolled speed adjustment in the operation of hydropower station due to small changes of initial values.
文摘In this paper, we provide a new approach to study the geometry of attractor. By applying category, we investigate the relationship between attractor and its attraction basin. In a complete metric space, we prove that the categories of attractor and its attraction basin are always equal. Then we apply this result to both autonomous and non-autonomous systems, and obtain a number of corresponding results.
文摘Arthur Miller's masterpiece Death of a Salesman is a very clear attack on the American success myth.The most dominant theme running throughout the play is Willy Loman's philosophy of personal attractiveness and its doomed futility.This philosophy not only brings failure to Willy's career but also destruction to Willy's family members.
文摘Spatial equity in access to urban services is a significant element of sustainable urban planning.To date,a service-based index is used to measure service attractiveness,considering attractiveness as a static concept.While from the user side view,service attractiveness is a dynamic concept related to the variation of different opportunities of users to use the services and capacities.In this paper,a user-based method for measuring service attractiveness is proposed.In this approach,the attractiveness of service for a user is modeled as a function of the user's Travel Times(TT),Free Times(FTs),park size and relative positions of the user,local demanding population,and service.Then,the inequity of attractiveness of services for different users has been examined using three inequity indices including the Duration of Use(DU),Frequency of Visit(FV),and the Chance of Space Choice(CSC).The proposed method is applied to urban regional parks of Tehran municipality.Traffc Analysis Zones(TAZs)and regional parks are respectively regarded as the users and services.In addition to considering inequity of access to the first closest park,the additional cost of accessing to the other two closest parks is also considered.Results show that the proposed method leads to the exploration of the existing inequities of DU,FV,and CSC among residents in local scales,whereas in the service-based method,all users of a service are highlighted with a single value of attractiveness.Comparison of the user-based and service-based attractiveness indices show significant differences.As an example,user-based attractiveness values of about 14%and 20%of TAZs are respectively 5 and 3 square meters more than that of the service-based attractiveness index.However,the service-based method is suitable for regional-scale comparison of the inequities.Therefore,the proposed index can complement the service-based index for inequity mapping and management in varying scales.
基金financially supported by the National Key Research and Development Program of China(2017YFD0201900)the National Natural Science Foundation of China(31621064)the earmarked fund for China Agriculture Research System(CARS-15-19)
文摘The multicolored Asian lady beetle, Harmonia axyridis(Coleoptera: Coccinellidae), is a common generalist predator in China and is occasionally found gathering on the Chinese pagoda tree, Sophora japonica, in summer. In a field investigation, we found that H. axyridis adults preferred S. japonica during its flowering period even though their optimal prey(aphid) is absent at this time. In addition, male and female adults were attracted to S. japonica flowers to a similar extent in a Y-tube olfactometer assay. Using coupled gas chromatography-electroantennogram detection(GC-EAD), we identified a flower odor component(nonanal) that elicited a significant electrophysiological response in H. axyridis. Electroantennogram(EAG) dose-dependent responses revealed that the amplitude of the adult beetle's EAG response increased with increasing concentration of nonanal, peaking at 10 mg mL^(–1). In Y-tube olfactometer behavioral tests, H. axyridis adults preferred a 10 mg mL^(–1) nonanal source over a 100 mg mL^(–1) diluent. Under field conditions, the adults were significantly attracted to both concentrations(10 and 100 mg mL^(–1)), and high concentrations generally had greater attraction. All these results suggest that nonanal, a volatile compound of S. japonica flowers, greatly attracts H. axyridis adults. This study provides a basis for the development of synthetic attractants of H. axyridis, with the potential to promote biocontrol services of this generalist predator in the native area(e.g., China) and to suppress its population by mass trapping in its invasive areas.
