We investigate the diffractive paraxial wave equation with an external potential,utilizing self-similarity and variable separation methods.The exact solution to this evolution equation,expressed through Scorer functio...We investigate the diffractive paraxial wave equation with an external potential,utilizing self-similarity and variable separation methods.The exact solution to this evolution equation,expressed through Scorer functions,gives rise to the new Scorer beams.We explore the dynamics of counterpropagating Scorer beams,as promising optical wave packets,focusing on their compression behavior.The Scorer beams are characterized by two key parameters:the attenuation factor and the initial pulse width.By appropriately adjusting these parameters,significant beam compression can be achieved.Specifically,increasing the attenuation factor enhances compression and raises pulse amplitude,while reducing the initial pulse width further amplifies these effects.Along the way,we observe interesting interference patterns of the counterpropagating Scorer beams that have never been seen before.This study introduces a novel approach to beam compression and opens new possibilities for practical applications of Scorer beams.展开更多
We study dark localized waves within a nonlinear system based on the Boussinesq approximation,describing the dynamics of shallow water waves.Employing symbolic calculus,we apply the Hirota bilinear method to transform...We study dark localized waves within a nonlinear system based on the Boussinesq approximation,describing the dynamics of shallow water waves.Employing symbolic calculus,we apply the Hirota bilinear method to transform an extended Boussinesq system into a bilinear form,and then use the multiple rogue wave method to obtain its dark rational solutions.Exploring the first-and second-order dark solutions,we examine the conditions under which these localized solutions exist and their spatiotemporal distributions.Through the selection of various parameters and by utilizing different visualization techniques(intensity distributions and contour plots),we explore the dynamical properties of dark solutions found:in particular,the first-and second-order dark rogue waves.We also explore the methods of their control.The findings presented here not only deepen the understanding of physical phenomena described by the(1+1)-dimensional Boussinesq equation,but also expand avenues for further research.Our method can be extended to other nonlinear systems,to conceivably obtain higher-order dark rogue waves.展开更多
The transformer core snubber （CS）, as one of the most important components in the EAST （experimental advanced superconducting tokamak） NBI （neutral beam injector） system, is designed to limit grid damage and pro...The transformer core snubber （CS）, as one of the most important components in the EAST （experimental advanced superconducting tokamak） NBI （neutral beam injector） system, is designed to limit grid damage and protect the ion source during periods of electrical breakdowns. A transformer core snubber is analyzed in detail in this paper. Several kinds of soft magnetic cores are presented and compared. With analysis and experiment on the basic characteristics of the cores, the most suitable materials are suggested. The circuit simulation code is established which could simulate faulty conditions with concentrated and distributed CS concepts. Based on the above work, an ion source CS is developed with series type of distributed topology. The CS has been subjected to experimental validation at 80 kV with a peak short-current of approximately 400 A in a real NBI system, which proves the accuracy of the adopted assumptions and the analysis method.展开更多
The uncertainty during the period of software project development often brings huge risks to contractors and clients. If we can find an effective method to predict the cost and quality of software projects based on fa...The uncertainty during the period of software project development often brings huge risks to contractors and clients. If we can find an effective method to predict the cost and quality of software projects based on facts like the project character and two-side cooperating capability at the beginning of the project,we can reduce the risk. Bayesian Belief Network(BBN) is a good tool for analyzing uncertain consequences, but it is difficult to produce precise network structure and conditional probability table.In this paper,we built up network structure by Delphi method for conditional probability table learning,and learn update probability table and nodes’confidence levels continuously according to the application cases, which made the evaluation network have learning abilities, and evaluate the software development risk of organization more accurately.This paper also introduces EM algorithm, which will enhance the ability to produce hidden nodes caused by variant software projects.展开更多
A greater focus of environmental protection is directed toward environmental regulations in China. This paper focuses on environmental regulations and their impact on textile industry. The academic circle does not rea...A greater focus of environmental protection is directed toward environmental regulations in China. This paper focuses on environmental regulations and their impact on textile industry. The academic circle does not reach a consensus on the relationship between environmental regulations and international competitiveness. Some hold the view that environmental regulations lower international competitiveness while others think that environmental regulations improve both environment and economic performance. This paper aims to analyze the impact of the environmental regulations on the international competitiveness of textile industry in China. This study starts with theories relative to this subject; the second part, based on the impact mechanism of environmental regulations on competitiveness, analyzes the environmental impact on textile from the perspective of cost and market. The conceptual exploration comes to the conclusion that environmental regulations make a negative impact on the international competitiveness on the cost side and improve it by means ofinnovation and product differentiation on market side; the third part gives time series evidence to examine the impact. In this part the Pearson Correlation Analysis is conducted based on the data of China's textile industry of the period from 1991 to 2005. It turns out to prove that the negative environmental impact on cost side exceeds the positive environmental impact on market side, namely, environmental regulations deteriorate the international competitiveness in textile industry as a whole during the inspected period.展开更多
The H_∞state estimation problem for a class of stochastic neural networks with Markovian jumping parameters and leakage delay is investigated in this paper.By employing a suitable Lyapunov functional and inequality t...The H_∞state estimation problem for a class of stochastic neural networks with Markovian jumping parameters and leakage delay is investigated in this paper.By employing a suitable Lyapunov functional and inequality technic,the suffcient conditions for exponential stability as well as prescribed H_∞norm level of the state estimation error system are proposed and verified,and all obtained results are expressed in terms of strict linear matrix inequalities(LMIs).Examples and simulations are presented to show the effectiveness of the proposed methods,at the same time,the effect of leakage delay on stability of neural networks system and on the attenuation level of state estimator are discussed.展开更多
The upper vertical stability （VS） feeder is a part connected to the upper VS coil by a welding joint. The function of the feeder is to transfer current and coolant water to the VS coil. A giant electron^agnetic forc...The upper vertical stability （VS） feeder is a part connected to the upper VS coil by a welding joint. The function of the feeder is to transfer current and coolant water to the VS coil. A giant electron^agnetic force will be generated during normal operation by the current flowing in the VS coils, interacting with the external background field. The Lorentz force will induce Tresca stress in the feeder. The amplitudes of the magnetic field and Lorentz force along the conductor running direction have been calculated based on Maxwell＇s equations. To extract the Tresca stress in the feeder, a finite element model was created using the software ANSYS and an electromagnetic load was applied on the model. According to the analytical design, the stresses were classified and evaluated based on ASME. In order to reduce the Tresca stress, some optimization works have been done and the Tresca stress has had a significant reduction in the optimized model. This analytical work figured out the stress distribution in the feeder and checked the feasibility of the prototype design model. The ANSYS analysis results will provide a guidance for later improvement and fabrication.展开更多
ELM （edge localized mode） coils are key components of ITER that suppress the edge localized mode phenomenon. A giant electromagnetic force is generated during normal operations by the current flowing in the ELM coil...ELM （edge localized mode） coils are key components of ITER that suppress the edge localized mode phenomenon. A giant electromagnetic force is generated during normal operations by the current flowing in the ELM coils interacting with the external background field. The Lorentz force will induce Tresca stress in the ELM coils. If the load goes beyond the allowable threshold, the coils can hardly satisfy the safety requirements. The right-hand bottom corner was chosen to perform our electromagnetic analyses. Based on the Maxwell equation, the detailed magnetic field and Lorentz force were calculated. By use of the finite element software ANSYS, the Tresca stress was extracted and evaluated based on our analytical design. The present analysis aims to verify the feasibility of the current design. It can also serve as guidance for fabrication and structural optimization.展开更多
We study analytically and numerically the propagation of spatial solitons in a two-dimensional stronglynonlocal nonlinear medium. Exact analytical solutions in the form of self-similar spatial solitons are obtained in...We study analytically and numerically the propagation of spatial solitons in a two-dimensional stronglynonlocal nonlinear medium. Exact analytical solutions in the form of self-similar spatial solitons are obtained involvinghigher-order Hermite-Gaussian functions. Our theoretical predictions provide new insights into the low-energy spatialsoliton transmission with high fidelity.展开更多
We theoretically demonstrate that Kerr media under self-focusing nonlinearity support three-dimensional spatiotemporal solitary waves in various patterns,such as necklace-,disk-,and vortex-ring shapes.The structures o...We theoretically demonstrate that Kerr media under self-focusing nonlinearity support three-dimensional spatiotemporal solitary waves in various patterns,such as necklace-,disk-,and vortex-ring shapes.The structures of these solitons are defined by the set of radial,orbital,and azimuthal quantum numbers,(n,l,m),respectively.展开更多
We present beam solutions of the strongly nonlocal nonlinear Schrodinger equation in left-handed mate- rims （LHMs）. Different Laguerre-Ganssian （LG） necklace beams, such as symmetric and asymmetric single layer an...We present beam solutions of the strongly nonlocal nonlinear Schrodinger equation in left-handed mate- rims （LHMs）. Different Laguerre-Ganssian （LG） necklace beams, such as symmetric and asymmetric single layer and multilayer necklace beams are created by the superposition of two single beams with different topological charges. Such superpositions are then propagated through LHMs, displaying linear diffraction. It is found that the superposition of two LGnm beams with opposite topological charges does not show rotational behavior and that there exists rotation for other topological charge combinations. Our theory predicts that the accessible solitons cannot exist in LHMs.展开更多
After the illustration of the concept of waterfront place and the construction situation of urban waterfront landscape in China, the paper has introduced design methods for waterfront environment. By taking the compre...After the illustration of the concept of waterfront place and the construction situation of urban waterfront landscape in China, the paper has introduced design methods for waterfront environment. By taking the comprehensive improvement of the environment of Xinxu River in Nanning City for example, the paper has analyzed the current situation of place image, interpreted the spirit of place, and considered that the place design should be based on characteristic and recognizable image, unified and diversified image, general and continuous image, accessible and humanistic image and ecological protective image of landscape sensitive area. And then, the planning and design idea for the place has been proposed, functional zones have been divided, and furthermore, landscape organization of waterfront spatial environment has been described in detail. It aims to create a humanistic, ecological, characteristic and recognizable waterfront landscape place with native spatial culture.展开更多
We take Shunde District,Foshan City in Guangdong Province for example,to carry out SWOT analysis of urban greening maintenance and management.The strengths of greening management and maintenance in Shunde District are...We take Shunde District,Foshan City in Guangdong Province for example,to carry out SWOT analysis of urban greening maintenance and management.The strengths of greening management and maintenance in Shunde District are as follows:(i)The greening area and quality are continuously improved in the downtown of Shunde District;(ii)The management and maintenance work is carried out well;(iii)The management and maintenance level tends to be increasingly perfected.The weaknesses of greening management and maintenance are as follows:(i)The fees for greening management and maintenance are very low;(ii)There is corner as yet untouched in the junction of some town streets;(iii)The greening management and maintenance technicians are unprofessional;(iv)The greening management is not in place;(v)There is management vacancy phenomenon in the management and maintenance of regional green space;(vi)The design and construction phase is flawed.Finally,based on the analysis of strengths and weaknesses of greening,we put forth the recommendations for the development of management and maintenance in urban green space.展开更多
We report on the localized spatial soliton excitations in the multidimensional nonlinear Schrodinger equation with radially variable nonlinearity coefficient and an external potential. By using Hirota＇s binary differ...We report on the localized spatial soliton excitations in the multidimensional nonlinear Schrodinger equation with radially variable nonlinearity coefficient and an external potential. By using Hirota＇s binary differential operators, we determine a variety of external potentials and nonlinearity coefficients that can support nonlinear localized solutions of different but desired forms. For some specific external potentials and nonlinearity coefficients, we discuss features of the corresponding （2＋1）-dimensional multisolitonic solutions, including ring solitons, lump solitons, and soliton clusters.展开更多
The key issues and challenges facing TEFL teachers in China with respect to prospective teacher preparation and professional development are discussed. Drawing upon earlier research on conceptual frameworks, the knowl...The key issues and challenges facing TEFL teachers in China with respect to prospective teacher preparation and professional development are discussed. Drawing upon earlier research on conceptual frameworks, the knowledge base of pre-service teachers is examined through research into the curriculums in TEFL education across diploma, undergraduate and postgraduate levels. A comparative study of the curriculum structures in the education of TEFL teachers reveals a number of key areas of concern： the main hindrance to the development of a stronger knowledge base of pre-service teachers lies in the serious shortage of pedagogical content knowledge, fundamental pedagogical knowledge that are currently available, as well as with the overall inadequacy of practicum hours. It strongly argues for the breadth versus depth in course design and calls for the imperative to reconceptualize the knowledge base of pre-service teachers.展开更多
This paper innovatively adopts an interdisciplinary method, which is urban design,combined with social investigation, statistical analysis, and case analysis. In this study, 1350residents in 45 blocks of Lansing were ...This paper innovatively adopts an interdisciplinary method, which is urban design,combined with social investigation, statistical analysis, and case analysis. In this study, 1350residents in 45 blocks of Lansing were selected as samples to investigate the related issuesof social capital, which include safety, contact with others, and sense of support for peopleliving in certain areas. There are two ways to measure the distance from the center of thecommunity to the nearest green space. One is the straight distance, while the other is pathdistance. Through statistical analysis, the path distance of less than 250 m is also added intothe variables. The results overturned the hypotheses and showed that the distance of greenspace was positively correlated with social capital. The residents of Lansing may prefer thedistant green space for recreational activities and create a way to participate in civic duty.The research can not only provide a basis for Lansing to formulate the appropriate resourcemanagement rules and norms and promote the accumulation of residents’ social capital, butalso provide a reference for urban green space planning in other areas. At the same time, inthe context of developing a smart city and constructing a new public system, we hope thatthe better optimization of the green space allocation will be achieved.展开更多
The development of inexpensive artificial photosynthetic(AP)systems,utilizing low-energy sunlight for CO_(2)reduction remains a significant challenge.Here,we report a red-light-driven CO_(2)reduction system with pyrid...The development of inexpensive artificial photosynthetic(AP)systems,utilizing low-energy sunlight for CO_(2)reduction remains a significant challenge.Here,we report a red-light-driven CO_(2)reduction system with pyridinethiolate-capped CdSe quantum dots(QDs)as the photosensitizers and a cobalt quarterpyridyl complex as the catalyst.This system,assembled from abundant elements,achieved efficient CO_(2)conversion to CO with over 97%selectivity and turnover numbers of 392 for cobalt and 7840 for QDs in aqueous solution.Over 92%selectivity was observed even at CO_(2)concentration as low as 1%,which showed potential for practical applications.To our knowledge,this is the first report of red-lightdriven CO_(2)photoreduction in QDs/catalyst-based photocatalytic systems.展开更多
Metal–organic cage photocatalysts with nanoscale dimensions have received wide attention in the field of photocatalytic environmental pollutant treatment due to their large cavities,easy modification,high tunability,...Metal–organic cage photocatalysts with nanoscale dimensions have received wide attention in the field of photocatalytic environmental pollutant treatment due to their large cavities,easy modification,high tunability,and enriched active sites.Herein,we prepared a series of dihydroanthracene-cored terpyridine-based metallo-cuboctahedron nanomaterials through a selfassembly method,which exhibited satisfactory degradation performance for persistent organic pollutants under visible light irradiation.In particular,under light conditions,S1-Zn,one of the prepared nanomaterials,produced photogenerated holes oxidizing water molecules to∙OH,which attacked ibuprofen(IBU)for up to 95% degradation.Simultaneously,the corresponding photogenerated electrons reduced the dissolved oxygen in water,producing 66.2μmol/L hydrogen peroxide.The obtained supramolecular photocatalytic materials have a stable structure with non-precious metals and do not require a sacrificial agent.The metal sites of metallo-cuboctahedrons adsorb pollutants and transfer captured holes to them,accelerating degradation and promoting simultaneous H_(2)O_(2) production.This work not only proposes a simple and efficient synthesis method for supramolecular photocatalysts but also opens up opportunities for efficient,low-cost,and multifunctional materials for environmental persistent organic pollutants treatment.展开更多
Thallium is a highly toxic metal,and trace amount of thallium(I)(Tl+)in potable water could cause a severe water crisis,which arouses the exploitation of highly-effective technology for purification of Tl+contaminated...Thallium is a highly toxic metal,and trace amount of thallium(I)(Tl+)in potable water could cause a severe water crisis,which arouses the exploitation of highly-effective technology for purification of Tl+contaminated water.This report proposes the multi-layered Prussian blue(PB)-decorated composite membranes(PBx@PDA/PEI-FP)based on the aminated filter papers for Tl+uptake.Extensively characterization by Fourier transform infrared spectrometer-attenuated total reflectance,scanning electron microscope,thermogravimetric analysis,X-ray photoelectron spectroscopy and X-ray diffraction were performed to confirm the in situ growth of cubic PB crystals on filter paper membrane surfaces via the aminated layers,and the successful fabrication of multi-layered PB overcoats via the increasing of aminated layers.The effect of PB layers on Tl+removal by PBx@PDA/PEI-FP from simulated drinking water was evaluated as well as the influence of different experimental conditions.A trade-off between PB decoration layer number and PB distribution sizes is existed in Tl+uptake by PBx@PDA/PEI-FP.The double-layered PB2@PDA/PEI-FP membrane showed the maximum sorption capacity,but its Tl+uptake performance was weakened by the acid,coexisting ions(K+and Na+)and powerful operation pressure,during filtrating a large volume of low-concentrated Tl+-containing water.However,the negative effect of coexisting ions on the Tl+uptake could be effectively eliminated in weak alkaline water,and the Tl+removal was increased up to 100%without any pressure driving for PB2@PDA/PEI-FP membrane.Most importantly,PB2@PDA/PEI-FP displayed the high-efficiency and high-selectivity in purifying the Tl+-spiked Pearl River water,in which the residual Tl+in filtrate was less than 2μg·L^(–1) to meet the drinking water standard of United States Environmental Protection Agency.This work provides a feasible avenue to safeguard the drinking water in remote and underdeveloped area via the energy-free operation.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.62275176the Natural Science Foundation of Guangdong Province,China,under Grant No.2022A1515010084+1 种基金by Key Projects of Basic Research and Applied Basic Research in Universities of Guangdong Province,China,under Grants Nos.2021ZDZX1118 and 2022ZDZX1079supported by the NPRP 13S-0121-200126 Project with the Qatar National Research Fund(a member of the Qatar Foundation).
文摘We investigate the diffractive paraxial wave equation with an external potential,utilizing self-similarity and variable separation methods.The exact solution to this evolution equation,expressed through Scorer functions,gives rise to the new Scorer beams.We explore the dynamics of counterpropagating Scorer beams,as promising optical wave packets,focusing on their compression behavior.The Scorer beams are characterized by two key parameters:the attenuation factor and the initial pulse width.By appropriately adjusting these parameters,significant beam compression can be achieved.Specifically,increasing the attenuation factor enhances compression and raises pulse amplitude,while reducing the initial pulse width further amplifies these effects.Along the way,we observe interesting interference patterns of the counterpropagating Scorer beams that have never been seen before.This study introduces a novel approach to beam compression and opens new possibilities for practical applications of Scorer beams.
基金supported by the National Natural Science Foundation of China(Grant No.62275176)the Natural Science Foundation of Guangdong Province,China(Grant No.2022A1515010084)+1 种基金Key projects of basic research and applied basic research in universities of Guangdong province,China(Grant Nos.2021ZDZX1118 and 2022ZDZX1079)supported by the NPRP 13S-0121-200126 project with the Qatar National Research Fund(a member of Qatar Foundation)。
文摘We study dark localized waves within a nonlinear system based on the Boussinesq approximation,describing the dynamics of shallow water waves.Employing symbolic calculus,we apply the Hirota bilinear method to transform an extended Boussinesq system into a bilinear form,and then use the multiple rogue wave method to obtain its dark rational solutions.Exploring the first-and second-order dark solutions,we examine the conditions under which these localized solutions exist and their spatiotemporal distributions.Through the selection of various parameters and by utilizing different visualization techniques(intensity distributions and contour plots),we explore the dynamical properties of dark solutions found:in particular,the first-and second-order dark rogue waves.We also explore the methods of their control.The findings presented here not only deepen the understanding of physical phenomena described by the(1+1)-dimensional Boussinesq equation,but also expand avenues for further research.Our method can be extended to other nonlinear systems,to conceivably obtain higher-order dark rogue waves.
基金supported by National Magnetic Confinement Fusion Science Program of China (Nos.2010GB108003, 2011GB113005-1)in part by the National Magnetic Confinement Fusion Science Program of China (No.2010GB108003)+1 种基金the State Basic Research Development Program of China (973 Program 2011GB113005-1)the Large Scientific Project of EAST Auxiliary Heating Upgrade
文摘The transformer core snubber （CS）, as one of the most important components in the EAST （experimental advanced superconducting tokamak） NBI （neutral beam injector） system, is designed to limit grid damage and protect the ion source during periods of electrical breakdowns. A transformer core snubber is analyzed in detail in this paper. Several kinds of soft magnetic cores are presented and compared. With analysis and experiment on the basic characteristics of the cores, the most suitable materials are suggested. The circuit simulation code is established which could simulate faulty conditions with concentrated and distributed CS concepts. Based on the above work, an ion source CS is developed with series type of distributed topology. The CS has been subjected to experimental validation at 80 kV with a peak short-current of approximately 400 A in a real NBI system, which proves the accuracy of the adopted assumptions and the analysis method.
文摘The uncertainty during the period of software project development often brings huge risks to contractors and clients. If we can find an effective method to predict the cost and quality of software projects based on facts like the project character and two-side cooperating capability at the beginning of the project,we can reduce the risk. Bayesian Belief Network(BBN) is a good tool for analyzing uncertain consequences, but it is difficult to produce precise network structure and conditional probability table.In this paper,we built up network structure by Delphi method for conditional probability table learning,and learn update probability table and nodes’confidence levels continuously according to the application cases, which made the evaluation network have learning abilities, and evaluate the software development risk of organization more accurately.This paper also introduces EM algorithm, which will enhance the ability to produce hidden nodes caused by variant software projects.
文摘A greater focus of environmental protection is directed toward environmental regulations in China. This paper focuses on environmental regulations and their impact on textile industry. The academic circle does not reach a consensus on the relationship between environmental regulations and international competitiveness. Some hold the view that environmental regulations lower international competitiveness while others think that environmental regulations improve both environment and economic performance. This paper aims to analyze the impact of the environmental regulations on the international competitiveness of textile industry in China. This study starts with theories relative to this subject; the second part, based on the impact mechanism of environmental regulations on competitiveness, analyzes the environmental impact on textile from the perspective of cost and market. The conceptual exploration comes to the conclusion that environmental regulations make a negative impact on the international competitiveness on the cost side and improve it by means ofinnovation and product differentiation on market side; the third part gives time series evidence to examine the impact. In this part the Pearson Correlation Analysis is conducted based on the data of China's textile industry of the period from 1991 to 2005. It turns out to prove that the negative environmental impact on cost side exceeds the positive environmental impact on market side, namely, environmental regulations deteriorate the international competitiveness in textile industry as a whole during the inspected period.
基金supported by the Research Fund for the Doctoral Program of Guang Dong Province of China (No. 2015A030310336)
文摘The H_∞state estimation problem for a class of stochastic neural networks with Markovian jumping parameters and leakage delay is investigated in this paper.By employing a suitable Lyapunov functional and inequality technic,the suffcient conditions for exponential stability as well as prescribed H_∞norm level of the state estimation error system are proposed and verified,and all obtained results are expressed in terms of strict linear matrix inequalities(LMIs).Examples and simulations are presented to show the effectiveness of the proposed methods,at the same time,the effect of leakage delay on stability of neural networks system and on the attenuation level of state estimator are discussed.
文摘The upper vertical stability （VS） feeder is a part connected to the upper VS coil by a welding joint. The function of the feeder is to transfer current and coolant water to the VS coil. A giant electron^agnetic force will be generated during normal operation by the current flowing in the VS coils, interacting with the external background field. The Lorentz force will induce Tresca stress in the feeder. The amplitudes of the magnetic field and Lorentz force along the conductor running direction have been calculated based on Maxwell＇s equations. To extract the Tresca stress in the feeder, a finite element model was created using the software ANSYS and an electromagnetic load was applied on the model. According to the analytical design, the stresses were classified and evaluated based on ASME. In order to reduce the Tresca stress, some optimization works have been done and the Tresca stress has had a significant reduction in the optimized model. This analytical work figured out the stress distribution in the feeder and checked the feasibility of the prototype design model. The ANSYS analysis results will provide a guidance for later improvement and fabrication.
文摘ELM （edge localized mode） coils are key components of ITER that suppress the edge localized mode phenomenon. A giant electromagnetic force is generated during normal operations by the current flowing in the ELM coils interacting with the external background field. The Lorentz force will induce Tresca stress in the ELM coils. If the load goes beyond the allowable threshold, the coils can hardly satisfy the safety requirements. The right-hand bottom corner was chosen to perform our electromagnetic analyses. Based on the Maxwell equation, the detailed magnetic field and Lorentz force were calculated. By use of the finite element software ANSYS, the Tresca stress was extracted and evaluated based on our analytical design. The present analysis aims to verify the feasibility of the current design. It can also serve as guidance for fabrication and structural optimization.
基金Supported by the Science Research Foundation of Shunde Polytechnic under Grant No. 2008-KJ06Supported by the NPRP 25-6-7-2 Project with the Qatar National Research Foundation
文摘We study analytically and numerically the propagation of spatial solitons in a two-dimensional stronglynonlocal nonlinear medium. Exact analytical solutions in the form of self-similar spatial solitons are obtained involvinghigher-order Hermite-Gaussian functions. Our theoretical predictions provide new insights into the low-energy spatialsoliton transmission with high fidelity.
基金Supported by the Natural Science Foundation of Guangdong Province under Grant No 1015283001000000Work at the Texas A&M University at Qatar was supported by the NPRP 09-462-1-074 Project with the Qatar National Research Foundation.
文摘We theoretically demonstrate that Kerr media under self-focusing nonlinearity support three-dimensional spatiotemporal solitary waves in various patterns,such as necklace-,disk-,and vortex-ring shapes.The structures of these solitons are defined by the set of radial,orbital,and azimuthal quantum numbers,(n,l,m),respectively.
基金Supported by the Science Research Foundation of Shunde Polytechnic (2008-KJ06), ChinaWork at the Texas A&M University at Qatar is supported by the NPRP 25-6-7-2 project with the Qatar National Research Foundation
文摘We present beam solutions of the strongly nonlocal nonlinear Schrodinger equation in left-handed mate- rims （LHMs）. Different Laguerre-Ganssian （LG） necklace beams, such as symmetric and asymmetric single layer and multilayer necklace beams are created by the superposition of two single beams with different topological charges. Such superpositions are then propagated through LHMs, displaying linear diffraction. It is found that the superposition of two LGnm beams with opposite topological charges does not show rotational behavior and that there exists rotation for other topological charge combinations. Our theory predicts that the accessible solitons cannot exist in LHMs.
文摘After the illustration of the concept of waterfront place and the construction situation of urban waterfront landscape in China, the paper has introduced design methods for waterfront environment. By taking the comprehensive improvement of the environment of Xinxu River in Nanning City for example, the paper has analyzed the current situation of place image, interpreted the spirit of place, and considered that the place design should be based on characteristic and recognizable image, unified and diversified image, general and continuous image, accessible and humanistic image and ecological protective image of landscape sensitive area. And then, the planning and design idea for the place has been proposed, functional zones have been divided, and furthermore, landscape organization of waterfront spatial environment has been described in detail. It aims to create a humanistic, ecological, characteristic and recognizable waterfront landscape place with native spatial culture.
基金Supported by Scientific Research Project of Shunde Daliang Urban Administration Bureau in 2010
文摘We take Shunde District,Foshan City in Guangdong Province for example,to carry out SWOT analysis of urban greening maintenance and management.The strengths of greening management and maintenance in Shunde District are as follows:(i)The greening area and quality are continuously improved in the downtown of Shunde District;(ii)The management and maintenance work is carried out well;(iii)The management and maintenance level tends to be increasingly perfected.The weaknesses of greening management and maintenance are as follows:(i)The fees for greening management and maintenance are very low;(ii)There is corner as yet untouched in the junction of some town streets;(iii)The greening management and maintenance technicians are unprofessional;(iv)The greening management is not in place;(v)There is management vacancy phenomenon in the management and maintenance of regional green space;(vi)The design and construction phase is flawed.Finally,based on the analysis of strengths and weaknesses of greening,we put forth the recommendations for the development of management and maintenance in urban green space.
基金Supported by the Natural Science Foundation of Guangdong Province under Grant No. 1015283001000000,Chinasupported by the NPRP 09-462-1-074 project with the Qatar National Research Foundation
文摘We report on the localized spatial soliton excitations in the multidimensional nonlinear Schrodinger equation with radially variable nonlinearity coefficient and an external potential. By using Hirota＇s binary differential operators, we determine a variety of external potentials and nonlinearity coefficients that can support nonlinear localized solutions of different but desired forms. For some specific external potentials and nonlinearity coefficients, we discuss features of the corresponding （2＋1）-dimensional multisolitonic solutions, including ring solitons, lump solitons, and soliton clusters.
文摘The key issues and challenges facing TEFL teachers in China with respect to prospective teacher preparation and professional development are discussed. Drawing upon earlier research on conceptual frameworks, the knowledge base of pre-service teachers is examined through research into the curriculums in TEFL education across diploma, undergraduate and postgraduate levels. A comparative study of the curriculum structures in the education of TEFL teachers reveals a number of key areas of concern： the main hindrance to the development of a stronger knowledge base of pre-service teachers lies in the serious shortage of pedagogical content knowledge, fundamental pedagogical knowledge that are currently available, as well as with the overall inadequacy of practicum hours. It strongly argues for the breadth versus depth in course design and calls for the imperative to reconceptualize the knowledge base of pre-service teachers.
基金supported by Project for Young Innovative Talents of Guangdong Provincial Department of Education in 2022(Research on the Integration Path of Industry and Education in Furniture Design under the Background of Rural Revitalization,Funding No.2022WQNCX255).
文摘This paper innovatively adopts an interdisciplinary method, which is urban design,combined with social investigation, statistical analysis, and case analysis. In this study, 1350residents in 45 blocks of Lansing were selected as samples to investigate the related issuesof social capital, which include safety, contact with others, and sense of support for peopleliving in certain areas. There are two ways to measure the distance from the center of thecommunity to the nearest green space. One is the straight distance, while the other is pathdistance. Through statistical analysis, the path distance of less than 250 m is also added intothe variables. The results overturned the hypotheses and showed that the distance of greenspace was positively correlated with social capital. The residents of Lansing may prefer thedistant green space for recreational activities and create a way to participate in civic duty.The research can not only provide a basis for Lansing to formulate the appropriate resourcemanagement rules and norms and promote the accumulation of residents’ social capital, butalso provide a reference for urban green space planning in other areas. At the same time, inthe context of developing a smart city and constructing a new public system, we hope thatthe better optimization of the green space allocation will be achieved.
基金the financial support provided by Sun Yat-sen University,Green Biotechnologies Research Center of Excellence(GBRCE)for Functional Molecular Engineering,China,the National Natural Science Foundation of China(grant no.22471301)Guangdong Basic and Applied Basic Research Foundation,China(grant no.2024A1515011465)+1 种基金Guangzhou Science and Technology Programme,China(grant no.2024A04J6419)the China Postdoctoral Science Foundation(grant nos.2022TQ0380 and 2022M723586).
文摘The development of inexpensive artificial photosynthetic(AP)systems,utilizing low-energy sunlight for CO_(2)reduction remains a significant challenge.Here,we report a red-light-driven CO_(2)reduction system with pyridinethiolate-capped CdSe quantum dots(QDs)as the photosensitizers and a cobalt quarterpyridyl complex as the catalyst.This system,assembled from abundant elements,achieved efficient CO_(2)conversion to CO with over 97%selectivity and turnover numbers of 392 for cobalt and 7840 for QDs in aqueous solution.Over 92%selectivity was observed even at CO_(2)concentration as low as 1%,which showed potential for practical applications.To our knowledge,this is the first report of red-lightdriven CO_(2)photoreduction in QDs/catalyst-based photocatalytic systems.
基金supported by the National Natural Science Foundation of China(Nos.22101061 to Z.Z.,21971257 to P.S.W.,and 52150056 and 52000044 to Z.H.C.)the Natural Science Foundation of Guangdong Province-Youth Enhancement Programme(No.2024A1515030235 to Z.Z.)+6 种基金Guangzhou Basic and Applied Basic Research of City and University(Institute)Joint Funding Project(Nos.SL2022A03J01050 to P.S.W.,SL2022A03J00929 to Z.Z.,and 202201022174 to T.-Z.X.)the Guangdong Provincial Pearl River Talents Program(No.2019QN01C243 to T.-Z.X.)the Science and Technology Projects in Guangzhou(No.202201010664 to T.W.)the Youth Project of Guangdong Natural Science Foundation(No.2021A1515110696 to Q.W.L.)the Characteristic Innovation Project of Guangdong Universities(No.2022KTSCX094 to Q.W.L.)the Technical Cooperation Project between Guangzhou University and Guangdong Guangye Inspection&Testing Group Co.,Ltd.(No.GK2023097)the Funding Program of Postgraduate Creative Ability Training in Guangzhou University(No.S202311078009 to Q.A.Y.).
文摘Metal–organic cage photocatalysts with nanoscale dimensions have received wide attention in the field of photocatalytic environmental pollutant treatment due to their large cavities,easy modification,high tunability,and enriched active sites.Herein,we prepared a series of dihydroanthracene-cored terpyridine-based metallo-cuboctahedron nanomaterials through a selfassembly method,which exhibited satisfactory degradation performance for persistent organic pollutants under visible light irradiation.In particular,under light conditions,S1-Zn,one of the prepared nanomaterials,produced photogenerated holes oxidizing water molecules to∙OH,which attacked ibuprofen(IBU)for up to 95% degradation.Simultaneously,the corresponding photogenerated electrons reduced the dissolved oxygen in water,producing 66.2μmol/L hydrogen peroxide.The obtained supramolecular photocatalytic materials have a stable structure with non-precious metals and do not require a sacrificial agent.The metal sites of metallo-cuboctahedrons adsorb pollutants and transfer captured holes to them,accelerating degradation and promoting simultaneous H_(2)O_(2) production.This work not only proposes a simple and efficient synthesis method for supramolecular photocatalysts but also opens up opportunities for efficient,low-cost,and multifunctional materials for environmental persistent organic pollutants treatment.
基金supported by the National Natural Science Foundation of China(Grant Nos.22006026,52270001)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023A1515012506,2019A1515110546)+4 种基金Science and Technology Program of Guangzhou(Grant No.202102080160)Project of Young Innovative Talents in Colleges and Universities of Guangdong Province(Grant No.2019KQNCX111)Outstanding Youth Project of Guangdong Natural Science Foundation(Grant No.2022B1515020030)Guangzhou Science and Technology Project(Grant Nos.202201020530,202201020200)Research Project of Guangzhou University(Grant No.YJ2023026).
文摘Thallium is a highly toxic metal,and trace amount of thallium(I)(Tl+)in potable water could cause a severe water crisis,which arouses the exploitation of highly-effective technology for purification of Tl+contaminated water.This report proposes the multi-layered Prussian blue(PB)-decorated composite membranes(PBx@PDA/PEI-FP)based on the aminated filter papers for Tl+uptake.Extensively characterization by Fourier transform infrared spectrometer-attenuated total reflectance,scanning electron microscope,thermogravimetric analysis,X-ray photoelectron spectroscopy and X-ray diffraction were performed to confirm the in situ growth of cubic PB crystals on filter paper membrane surfaces via the aminated layers,and the successful fabrication of multi-layered PB overcoats via the increasing of aminated layers.The effect of PB layers on Tl+removal by PBx@PDA/PEI-FP from simulated drinking water was evaluated as well as the influence of different experimental conditions.A trade-off between PB decoration layer number and PB distribution sizes is existed in Tl+uptake by PBx@PDA/PEI-FP.The double-layered PB2@PDA/PEI-FP membrane showed the maximum sorption capacity,but its Tl+uptake performance was weakened by the acid,coexisting ions(K+and Na+)and powerful operation pressure,during filtrating a large volume of low-concentrated Tl+-containing water.However,the negative effect of coexisting ions on the Tl+uptake could be effectively eliminated in weak alkaline water,and the Tl+removal was increased up to 100%without any pressure driving for PB2@PDA/PEI-FP membrane.Most importantly,PB2@PDA/PEI-FP displayed the high-efficiency and high-selectivity in purifying the Tl+-spiked Pearl River water,in which the residual Tl+in filtrate was less than 2μg·L^(–1) to meet the drinking water standard of United States Environmental Protection Agency.This work provides a feasible avenue to safeguard the drinking water in remote and underdeveloped area via the energy-free operation.
