Diseases in tea trees can result in significant losses in both the quality and quantity of tea production.Regular monitoring can help to prevent the occurrence of large-scale diseases in tea plantations.However,existi...Diseases in tea trees can result in significant losses in both the quality and quantity of tea production.Regular monitoring can help to prevent the occurrence of large-scale diseases in tea plantations.However,existingmethods face challenges such as a high number of parameters and low recognition accuracy,which hinders their application in tea plantation monitoring equipment.This paper presents a lightweight I-MobileNetV2 model for identifying diseases in tea leaves,to address these challenges.The proposed method first embeds a Coordinate Attention(CA)module into the originalMobileNetV2 network,enabling the model to locate disease regions accurately.Secondly,a Multi-branch Parallel Convolution(MPC)module is employed to extract disease features across multiple scales,improving themodel’s adaptability to different disease scales.Finally,the AutoML for Model Compression(AMC)is used to compress themodel and reduce computational complexity.Experimental results indicate that our proposed algorithm attains an average accuracy of 96.12%on our self-built tea leaf disease dataset,surpassing the original MobileNetV2 by 1.91%.Furthermore,the number of model parameters have been reduced by 40%,making itmore suitable for practical application in tea plantation environments.展开更多
In this paper,a new finite element and finite difference(FE-FD)method has been developed for anisotropic parabolic interface problems with a known moving interface using Cartesian meshes.In the spatial discretization,...In this paper,a new finite element and finite difference(FE-FD)method has been developed for anisotropic parabolic interface problems with a known moving interface using Cartesian meshes.In the spatial discretization,the standard P,FE discretization is applied so that the part of the coefficient matrix is symmetric positive definite,while near the interface,the maximum principle preserving immersed interface discretization is applied.In the time discretization,a modified Crank-Nicolson discretization is employed so that the hybrid FE-FD is stable and second order accurate.Correction terms are needed when the interface crosses grid lines.The moving interface is represented by the zero level set of a Lipschitz continuous function.Numerical experiments presented in this paper confirm second orderconvergence.展开更多
Nowadays Surveying and Mapping(S&M)production and services are facing some serious challenges such as real-timization of data acquisition,automation of information processing,and intellectualization of service app...Nowadays Surveying and Mapping(S&M)production and services are facing some serious challenges such as real-timization of data acquisition,automation of information processing,and intellectualization of service applications.The main reason is that current digitalized S&M technologies,which involve complex algorithms and models as the core,are incapable of completely describing and representing the diverse,multi-dimensional and dynamic real world,as well as addressing high-dimensional and nonlinear spatial problems using simple algorithms and models.In order to address these challenges,it is necessary to explore the use of natural intelligence in S&M,and to develop intelligentized S&M technologies,which are knowledge-guided and algorithm-based.This paper first discusses the basic concepts and ideas of intelligentized S&M,and then analyzes and defines its fundamental issues in the analysis and modeling of natural intelligence in S&M,the construction and realization of hybrid intelligent computing paradigm,and the mechanism and path of empowering production.Further research directions are then proposed in the four areas,including knowledge systems,technologies and methodologies,application systems,and instruments and equipments of intelligentized S&M.Finally,some institutional issues related to promoting scientific research and engineering applications in this area are discussed.展开更多
The immersed boundary method is well-known,popular,and has had vast areas of applications due to its simplicity and robustness even though it is only first order accurate near the interface.In this paper,an immersed b...The immersed boundary method is well-known,popular,and has had vast areas of applications due to its simplicity and robustness even though it is only first order accurate near the interface.In this paper,an immersed boundary-augmented method has been developed for linear elliptic boundary value problems on arbitrary domains(exterior or interior)with a Dirichlet boundary condition.The new method inherits the simplicity,robustness,and first order convergence of the IB method but also provides asymptotic first order convergence of partial derivatives.Numerical examples are provided to confirm the analysis.展开更多
The validity of the tangent linear model(TLM)is studied numerically using the example of the Lorenz equations in this paper.The relationship between the limit of the validity time of the TLM and initial perturbations ...The validity of the tangent linear model(TLM)is studied numerically using the example of the Lorenz equations in this paper.The relationship between the limit of the validity time of the TLM and initial perturbations for the Lorenz equations is investigated using the Monte Carlo sampling method.A new error function between the nonlinear and the linear evolution of the perturbations is proposed.Furthermore,numerical sensitivity analysis is carried to establish the relationship between parameters and the validity of the TLM,such as the initial perturbation,the prediction time,the time step size and so on,by the method of mathematical statistics.展开更多
Pt/WO3/C nanocomposites with parallel WO3 nanorods were synthesized and applied as the cathode catalyst for proton exchange membrane fuel cells (PEMFCs). Electrochemical results and single cell tests show that an en...Pt/WO3/C nanocomposites with parallel WO3 nanorods were synthesized and applied as the cathode catalyst for proton exchange membrane fuel cells (PEMFCs). Electrochemical results and single cell tests show that an enhanced activity for the oxygen reduction reaction (ORR) is obtained for the Pt/WO3/C catalyst compared with Pt/C. The higher catalytic activity might be ascribed to the improved Pt dispersion with smaller particle sizes. The Pt/WO3/C catalyst also exhibits a good electrochemical stability under potential cycling. Thus, the Pt/WO3/C catalyst can be used as a potential PEMFC cathode catalyst.展开更多
In this paper,a class of new immersed interface finite element methods (IIFEM) is developed to solve elasticity interface problems with homogeneous and non-homogeneous jump conditions in two dimensions.Simple non-body...In this paper,a class of new immersed interface finite element methods (IIFEM) is developed to solve elasticity interface problems with homogeneous and non-homogeneous jump conditions in two dimensions.Simple non-body-fitted meshes are used.For homogeneous jump conditions,both non-conforming and conforming basis functions are constructed in such a way that they satisfy the natural jump conditions. For non-homogeneous jump conditions,a pair of functions that satisfy the same non-homogeneous jump conditions are constructed using a level-set representation of the interface.With such a pair of functions,the discontinuities across the interface in the solution and flux are removed;and an equivalent elasticity interface problem with homogeneous jump conditions is formulated.Numerical examples are presented to demonstrate that such methods have second order convergence.展开更多
The wild Cymbidium lowianum, a national-level rare and endangered species of Orchid, is an excellent garden plant with ornamental flowers with striking, deep red lips in a V-shaped formation. The objective of this stu...The wild Cymbidium lowianum, a national-level rare and endangered species of Orchid, is an excellent garden plant with ornamental flowers with striking, deep red lips in a V-shaped formation. The objective of this study was to establish a micropropagation protocol system via immature seeds of wild Cymbidium lowianum, evaluate the Murashige and Skoog (MS), half-strength Murashige and Skoog (1/2 MS) medium, 6-benzylaminopurine (BA), a-napthaleneacetic acid (NAA), organic additions activated charcoal (AC) and banana pulp (BP) effects on the different morphogenesis (seed germination, multiple shoot and rooting) in vitro. The optimal combination for the germination of seed was 1.0 mg·L-1 BA with 0.5 mg·L-1 NAA in 1/2 MS, and addition 0.3%AC, which resulted in 95% seed germination in 90 days. The best formulation for multiple shoot was 1/2 MS medium containing 2.5 mg·L-1 BA, 0.5 mg·L-1 NAA and addition 8% BP in which produced 19.8 shoots per protocorm in 60 days. Multiple shoots were cut and rooted in 1/2 MS supplemented with 1.5 mg·L-1 NAA,0.1 mg·L-1 BA and 0.3% AC, roots initiated 20 days after culture, the rooting percentages reached to 100%, in which 4.7 per shoot produced roots in 60 days. The survival rate of plantlet was up to 92% in moss after 30 days. This finding reveals that it is possible to obtain in vitro culture of Cymbidium lowianum using immature seeds in asymbiotic culture.展开更多
To improve the response rate of immune checkpoint inhibitors such as anti-PD-L1 antibody in immunosup-pressive cancers like triple-negative breast cancer(TNBC),induction of immunogenic cell death(ICD)at tumor sites ca...To improve the response rate of immune checkpoint inhibitors such as anti-PD-L1 antibody in immunosup-pressive cancers like triple-negative breast cancer(TNBC),induction of immunogenic cell death(ICD)at tumor sites can increase the antigenicity and adjuvanticity to activate the immune microenvironment so that tumors become sensitive to the intervention of immune checkpoint inhibitors.Herein,a self-amplified biomimetic nanosystem,mEHGZ,was constructed by encapsulation of epirubicin(EPI),glucose oxidase(Gox)and hemin in ZIF-8 nanoparticles and coating of the nanoparticles with calreticulin(CRT)over-expressed tumor cell mem-brane.EPI acts as an ICD inducer,Gox and hemin medicate the cascade generation of reactive oxygen species(ROS)to strengthen the ICD effect,and CRT-rich membrane as“eat me”signal promote presentation of the released antigens by dendritic cells(DCs)to invoke the tumor-immunity cycle.The biomimetic delivery system displays an amplified ICD effect via Gox oxidation,hydroxyl radical generation and glutathione(GSH)depletion.The induced potent ICD effect promotes DCs maturation and cytotoxic T lymphocytes(CTLs)infiltration,reversing an immunosuppressive tumor microenvironment to an immunoresponsive one.Treatment with the nanosystem in combination with anti-PD-L1 antibody results in distinctive inhibition of tumor growth and lung metastasis,supporting that a potent ICD effect can significantly boost the therapeutic efficacy of the anti-PD-L1 antibody.This self-amplified biomimetic nanoplatform offers a promising means of raising the response rate of immune checkpoint inhibitors.展开更多
Map is one of the communication means created by human being.Cartographers have been making efforts on the comparison of maps to natural languages so as to establish a"cartographic language"or"map langu...Map is one of the communication means created by human being.Cartographers have been making efforts on the comparison of maps to natural languages so as to establish a"cartographic language"or"map language".One of such efforts is to adopt the Shannon’s Information Theory originated in digital communication into cartography so as to establish an entropy-based cartographic communication theory.However,success has been very limited although research work had started as early as the mid-1960 s.It is then found that the bottleneck problem was the lack of appropriate measures for the spatial(configurational)information of(graphic and image)maps,as the classic Shannon entropy is only capable of characterizing statistical information but fails to capture the configurational information of(graphic and image)maps.Fortunately,after over 40-year development,some bottleneck problems have been solved.More precisely,generalized Shannon entropies for metric and thematic information of(graphic)maps have been developed and the first feasible solution for computing the Boltzmann entropy of image maps has been invented,which is capable of measuring the spatial information of not only numerical images but also categorical maps.With such progress,it is now feasible to build the"Information Theory of Cartography".In this paper,a framework for such a theory is proposed and some key issues are identified.For these issues,some have already been tackled while others still need efforts.As a result,a research agenda is set for future action.After all these issues are tackled,the theory will become matured so as to become a theoretic basis of cartography.It is expected that the Information Theory of Cartography will play an increasingly important role in the discipline of cartography because more and more researchers have advocated that information is more fundamental than matter and energy.展开更多
Being parent materials of two-dimensional (2D) crystals, van der Waals layered materials have received revived interest. In most 2D materials, the interaction between electrons is negligible. Introducing the interacti...Being parent materials of two-dimensional (2D) crystals, van der Waals layered materials have received revived interest. In most 2D materials, the interaction between electrons is negligible. Introducing the interaction can give rise to a variety of exotic properties. Here, via intercalating a van der Waals layered compound VS2, we find evidence for electron correlation by extensive magnetic, thermal, electrical, and thermoelectric characterizations. The low temperature Sommerfeld coefficient is 64 mJ·K-2·mol-1 and the Kadowaki-Woods ratio rKW^0.20a0. Both supports an enhancement of the electron correlation. The temperature dependences of the resistivity and thermopower indicate an important role played by the Kondo effect. The Kondo temperature TK is estimated to be around 8 K. Our results suggest intercalation as a potential means to engineer the electron correlation in van der Waals materials, as well as 2D materials.展开更多
The Onsager-Casimir reciprocal relations are a fundamental symmetry of nonequilibrium statistical systems.Here we study an unusual chirality-dependent Hall effect in a tilted Weyl semimetal Co_(3)Sn_(2)S_(2) with brok...The Onsager-Casimir reciprocal relations are a fundamental symmetry of nonequilibrium statistical systems.Here we study an unusual chirality-dependent Hall effect in a tilted Weyl semimetal Co_(3)Sn_(2)S_(2) with broken time-reversal symmetry.It is confirmed that the reciprocal relations are satisfied.Since two Berry curvature effects,an anomalous velocity and a chiral chemical potential,contribute to the observed Hall effect,the reciprocal relations suggest their intriguing connection.展开更多
In recent years,there has been a major surge of interest in the development of simulation techniques and strategies for fluid-structure interaction(FSI)problems,mainly driven by a large spectrum of applications in phy...In recent years,there has been a major surge of interest in the development of simulation techniques and strategies for fluid-structure interaction(FSI)problems,mainly driven by a large spectrum of applications in physiology,medical sciences,material sciences,manufacturing processes,and many other engineering disciplines.展开更多
The authors regret the incorrect publication of corresponding authors for the article.The corresponding authors have been updated as Hongyan Zhu(hyzhu_hmrrc@126.com)and Kui Luo(luokui@scu.edu.cn),and the same should b...The authors regret the incorrect publication of corresponding authors for the article.The corresponding authors have been updated as Hongyan Zhu(hyzhu_hmrrc@126.com)and Kui Luo(luokui@scu.edu.cn),and the same should be updated in the supplementary file as well.展开更多
Despite the great potential of anti-PD-L1 antibodies for immunotherapy,their low response rate due to an immunosuppressive tumor microenvironment has hampered their application.To address this issue,we constructed a c...Despite the great potential of anti-PD-L1 antibodies for immunotherapy,their low response rate due to an immunosuppressive tumor microenvironment has hampered their application.To address this issue,we constructed a cell membrane-coated nanosystem(mB4S)to reverse an immunosuppressive microenvironment to an immuno-supportive one for strengthening the anti-tumor effect.In this system,Epirubicin(EPI)as an immunogenic cell death(ICD)inducer was coupled to a branched glycopolymer via hydrazone bonds and diABZI as a stimulator of interferon genes(STING)agonist was encapsulated into mB4S.After internalization of mB4S,EPI was acidic-responsively released to induce ICD,which was characterized by an increased level of calreticulin(CRT)exposure and enhanced ATP secretion.Meanwhile,diABZI effectively activated the STING pathway.Treatment with mB4S in combination with an anti-PD-L1 antibody elicited potent immune responses by increasing the ratio of matured dendritic cells(DCs)and CD8+T cells,promoting cytokines secretion,up-regulating M1-like tumor-associated macrophages(TAMs)and down-regulating immunosuppressive myeloid-derived suppressor cells(MDSCs).Therefore,this nanosystem for co-delivery of an ICD inducer and a STING agonist achieved promotion of DCs maturation and CD8+T cells infiltration,creating an immuno-supportive microenvironment,thus potentiating the therapy effect of the anti-PD-L1 antibody in both 4T1 breast and CT26 colon tumor mice.展开更多
Understanding the competition and coexistence of flagship carnivores is key to creating strategies for their conservation in the face of global carnivore declines.Although studies exploring the dynamics and competitio...Understanding the competition and coexistence of flagship carnivores is key to creating strategies for their conservation in the face of global carnivore declines.Although studies exploring the dynamics and competition between tigers(Panthera tigris)and leopards(P.pardus)span decades,there is a lack of understanding regarding the factors that influence their coexistence mechanisms on a broad scale,as well as the drivers determining their exploitative and interference competition.We gathered a comprehensive list of research papers among which 36 papers explored the interspecific interactions between tigers and leopards and tested the influence of biotic and abiotic factors on the coexistence mechanisms along three dimensions using multiple response variables regression models;we also tested the influence of ecological drivers determining the exploitative or interference competition between tigers and leopards.Elevation and ungulate density were the most important predictors in regulating the coexistence mechanisms.Tigers and leopards exhibited more positive relations/higher overlaps as elevation increased in the spatial niche.In addition,they showed a higher dietary overlap in the prey-rich regions.We determined that interference competition between tigers and leopards was less frequently observed in habitats with dense tree cover and homogeneous vegetation structures.Meanwhile,studies with multiple metrics would promote the detection of interference competition.Our study provides new insight into the competitive interactions and coexistence mechanisms of tigers and leopards on a broad scale.Policy-makers and managers should pay more attention to the factors of elevation,prey abundance,and habitat structures for the conservation of tigers and leopards.展开更多
Land use reflects human activities on land.Urban land use is the highest level human alteration on Earth,and it is rapidly changing due to population increase and urbanization.Urban areas have widespread effects on lo...Land use reflects human activities on land.Urban land use is the highest level human alteration on Earth,and it is rapidly changing due to population increase and urbanization.Urban areas have widespread effects on local hydrology,climate,biodiversity,and food production[1,2].However,maps,that contain knowledge on the distribution,pattern and composition of various land use types in urban areas,are limited to city level.The mapping standard on data sources,methods,land use classification schemes varies from city to city,due to differences in financial input and skills of mapping personnel.To address various national and global environmental challenges caused by urbanization,it is important to have urban land uses at the national and global scales that are derived from the same or consistent data sources with the same or compatible classification systems and mapping methods.This is because,only with urban land use maps produced with similar criteria,consistent environmental policies can be made,and action efforts can be compared and assessed for large scale environmental administration.However,despite of the fact that a number of urban-extent maps exist at global scales[3,4],more detailed urban land use maps do not exist at the same scale.Even at big country or regional levels such as for the United States,China and European Union,consistent land use mapping efforts are rare[5,6](e.g.,https://sdi4apps.eu/open_land_use/).展开更多
In the past few decades, with the growing popularity of compressed sensing (CS) in the signal processing field, the quantization step in CS has received significant attention. Current research generally considers mu...In the past few decades, with the growing popularity of compressed sensing (CS) in the signal processing field, the quantization step in CS has received significant attention. Current research generally considers multi-bit quantization. For systems employing quantization with a sufficient number of bits, a sparse signal can be reliably recovered using various CS reconstruction algorithms. Recently, many researchers have begun studying the one- bit quantization case for CS. As an extreme case of CS, one- bit CS preserves only the sign information of measurements, which reduces storage costs and hardware complexity. By treating one-bit measurements as sign constraints, it has been shown that sparse signals can be recovered using certain reconstruction algorithms with a high probability. Based on the merits of one-bit CS, it has been widely applied to many fields, such as radar, source location, spectrum sensing, and wireless sensing network. In this paper, the characteristics of one-bit CS and related works are reviewed. First, the framework of one-bit CS is introduced. Next, we summarize existing reconstruction algorithms. Additionally, some extensions and practical applications of one-bit CS are categorized and discussed. Finally, our conclusions and the further research topics are summarized.展开更多
种群密度估计对野生动物的保护和管理至关重要,也是动物生态学和保护生物学备受关注的研究热点,但对大中型兽类种群数量的准确估算一直面临挑战。红外相机是哺乳动物调查中普遍采用的工具,也是克服这一挑战的一种经济有效的方法。目前...种群密度估计对野生动物的保护和管理至关重要,也是动物生态学和保护生物学备受关注的研究热点,但对大中型兽类种群数量的准确估算一直面临挑战。红外相机是哺乳动物调查中普遍采用的工具,也是克服这一挑战的一种经济有效的方法。目前国际上已有多种方法采用红外相机数据估算不可个体识别动物的种群密度,但相关技术在我国的应用案例较少,本文旨在为国内研究者应用红外相机数据估算动物种群密度提供参考。首先,我们介绍了随机相遇模型(randomencounter model,REM)、随机相遇与停留时间(random encounter and staying time,REST)模型、相机前停留时间(time in front of the camera,TIFC)模型以及红外相机距离取样(cameratrapdistancesampling,CTDS)这四种模型的基本原理和假设;其次,描述了这些模型在野外调查中的技术要点,并给出数据处理与分析的建议;最后,总结了每个模型的数据需求、优点和缺点。虽然我国目前拥有估算种群密度的大量红外相机数据源,但有很多物种的数量尚未知晓,也没有一种方法对所有红外相机数据都是最优的,所以我们建议研究者在了解所研究动物类群的生活史和生态需求基础上,根据模型假设确定合理的采样和分析方案,扩大这些方法的应用,为我国重要物种的保护和保护地建设提供科学指导。展开更多
基金supported by National Key Research and Development Program(No.2016YFD0201305-07)Guizhou Provincial Basic Research Program(Natural Science)(No.ZK[2023]060)Open Fund Project in Semiconductor Power Device Reliability Engineering Center of Ministry of Education(No.ERCMEKFJJ2019-06).
文摘Diseases in tea trees can result in significant losses in both the quality and quantity of tea production.Regular monitoring can help to prevent the occurrence of large-scale diseases in tea plantations.However,existingmethods face challenges such as a high number of parameters and low recognition accuracy,which hinders their application in tea plantation monitoring equipment.This paper presents a lightweight I-MobileNetV2 model for identifying diseases in tea leaves,to address these challenges.The proposed method first embeds a Coordinate Attention(CA)module into the originalMobileNetV2 network,enabling the model to locate disease regions accurately.Secondly,a Multi-branch Parallel Convolution(MPC)module is employed to extract disease features across multiple scales,improving themodel’s adaptability to different disease scales.Finally,the AutoML for Model Compression(AMC)is used to compress themodel and reduce computational complexity.Experimental results indicate that our proposed algorithm attains an average accuracy of 96.12%on our self-built tea leaf disease dataset,surpassing the original MobileNetV2 by 1.91%.Furthermore,the number of model parameters have been reduced by 40%,making itmore suitable for practical application in tea plantation environments.
基金partially supported by the National Natural Science Foundation of China(Grant No.12261070)the Ningxia Key Research and Development Project of China(Grant No.2022BSB03048)+2 种基金partially supported by the Simons(Grant No.633724)and by Fundacion Seneca grant 21760/IV/22partially supported by the Spanish national research project PID2019-108336GB-I00by Fundacion Séneca grant 21728/EE/22.Este trabajo es resultado de las estancias(21760/IV/22)y(21728/EE/22)financiadas por la Fundacion Séneca-Agencia de Ciencia y Tecnologia de la Region de Murcia con cargo al Programa Regional de Movilidad,Colaboracion Internacional e Intercambio de Conocimiento"Jimenez de la Espada".(Plan de Actuacion 2022).
文摘In this paper,a new finite element and finite difference(FE-FD)method has been developed for anisotropic parabolic interface problems with a known moving interface using Cartesian meshes.In the spatial discretization,the standard P,FE discretization is applied so that the part of the coefficient matrix is symmetric positive definite,while near the interface,the maximum principle preserving immersed interface discretization is applied.In the time discretization,a modified Crank-Nicolson discretization is employed so that the hybrid FE-FD is stable and second order accurate.Correction terms are needed when the interface crosses grid lines.The moving interface is represented by the zero level set of a Lipschitz continuous function.Numerical experiments presented in this paper confirm second orderconvergence.
基金The Key Program of the National Natural Science Foundation of China(No.41930650)The Strategic Consulting Project of Chinese Academy of Engineering(No.2019-ZD-16)。
文摘Nowadays Surveying and Mapping(S&M)production and services are facing some serious challenges such as real-timization of data acquisition,automation of information processing,and intellectualization of service applications.The main reason is that current digitalized S&M technologies,which involve complex algorithms and models as the core,are incapable of completely describing and representing the diverse,multi-dimensional and dynamic real world,as well as addressing high-dimensional and nonlinear spatial problems using simple algorithms and models.In order to address these challenges,it is necessary to explore the use of natural intelligence in S&M,and to develop intelligentized S&M technologies,which are knowledge-guided and algorithm-based.This paper first discusses the basic concepts and ideas of intelligentized S&M,and then analyzes and defines its fundamental issues in the analysis and modeling of natural intelligence in S&M,the construction and realization of hybrid intelligent computing paradigm,and the mechanism and path of empowering production.Further research directions are then proposed in the four areas,including knowledge systems,technologies and methodologies,application systems,and instruments and equipments of intelligentized S&M.Finally,some institutional issues related to promoting scientific research and engineering applications in this area are discussed.
文摘The immersed boundary method is well-known,popular,and has had vast areas of applications due to its simplicity and robustness even though it is only first order accurate near the interface.In this paper,an immersed boundary-augmented method has been developed for linear elliptic boundary value problems on arbitrary domains(exterior or interior)with a Dirichlet boundary condition.The new method inherits the simplicity,robustness,and first order convergence of the IB method but also provides asymptotic first order convergence of partial derivatives.Numerical examples are provided to confirm the analysis.
基金This project is Supported by the National Natural Science Foundation of China(Grant Nos.11471166 and 11426134)the Natural Science Foundation of Jiangsu Province(Grant No.BK20141443).
文摘The validity of the tangent linear model(TLM)is studied numerically using the example of the Lorenz equations in this paper.The relationship between the limit of the validity time of the TLM and initial perturbations for the Lorenz equations is investigated using the Monte Carlo sampling method.A new error function between the nonlinear and the linear evolution of the perturbations is proposed.Furthermore,numerical sensitivity analysis is carried to establish the relationship between parameters and the validity of the TLM,such as the initial perturbation,the prediction time,the time step size and so on,by the method of mathematical statistics.
基金financially supported by the National Natural Science Fundation of China(No.51125007)the National Basic Research Program(No.2012CB215500)
文摘Pt/WO3/C nanocomposites with parallel WO3 nanorods were synthesized and applied as the cathode catalyst for proton exchange membrane fuel cells (PEMFCs). Electrochemical results and single cell tests show that an enhanced activity for the oxygen reduction reaction (ORR) is obtained for the Pt/WO3/C catalyst compared with Pt/C. The higher catalytic activity might be ascribed to the improved Pt dispersion with smaller particle sizes. The Pt/WO3/C catalyst also exhibits a good electrochemical stability under potential cycling. Thus, the Pt/WO3/C catalyst can be used as a potential PEMFC cathode catalyst.
基金supported by the US ARO grants 49308-MA and 56349-MAthe US AFSOR grant FA9550-06-1-024+1 种基金he US NSF grant DMS-0911434the State Key Laboratory of Scientific and Engineering Computing of Chinese Academy of Sciences during a visit by Z.Li between July-August,2008.
文摘In this paper,a class of new immersed interface finite element methods (IIFEM) is developed to solve elasticity interface problems with homogeneous and non-homogeneous jump conditions in two dimensions.Simple non-body-fitted meshes are used.For homogeneous jump conditions,both non-conforming and conforming basis functions are constructed in such a way that they satisfy the natural jump conditions. For non-homogeneous jump conditions,a pair of functions that satisfy the same non-homogeneous jump conditions are constructed using a level-set representation of the interface.With such a pair of functions,the discontinuities across the interface in the solution and flux are removed;and an equivalent elasticity interface problem with homogeneous jump conditions is formulated.Numerical examples are presented to demonstrate that such methods have second order convergence.
文摘The wild Cymbidium lowianum, a national-level rare and endangered species of Orchid, is an excellent garden plant with ornamental flowers with striking, deep red lips in a V-shaped formation. The objective of this study was to establish a micropropagation protocol system via immature seeds of wild Cymbidium lowianum, evaluate the Murashige and Skoog (MS), half-strength Murashige and Skoog (1/2 MS) medium, 6-benzylaminopurine (BA), a-napthaleneacetic acid (NAA), organic additions activated charcoal (AC) and banana pulp (BP) effects on the different morphogenesis (seed germination, multiple shoot and rooting) in vitro. The optimal combination for the germination of seed was 1.0 mg·L-1 BA with 0.5 mg·L-1 NAA in 1/2 MS, and addition 0.3%AC, which resulted in 95% seed germination in 90 days. The best formulation for multiple shoot was 1/2 MS medium containing 2.5 mg·L-1 BA, 0.5 mg·L-1 NAA and addition 8% BP in which produced 19.8 shoots per protocorm in 60 days. Multiple shoots were cut and rooted in 1/2 MS supplemented with 1.5 mg·L-1 NAA,0.1 mg·L-1 BA and 0.3% AC, roots initiated 20 days after culture, the rooting percentages reached to 100%, in which 4.7 per shoot produced roots in 60 days. The survival rate of plantlet was up to 92% in moss after 30 days. This finding reveals that it is possible to obtain in vitro culture of Cymbidium lowianum using immature seeds in asymbiotic culture.
基金National Natural Science Foundation of China(52073193,51873120 and 81621003)1‧3‧5 Project for Disciplines of Excellence,West China Hospital,Sichuan University(ZYJC21013)。
文摘To improve the response rate of immune checkpoint inhibitors such as anti-PD-L1 antibody in immunosup-pressive cancers like triple-negative breast cancer(TNBC),induction of immunogenic cell death(ICD)at tumor sites can increase the antigenicity and adjuvanticity to activate the immune microenvironment so that tumors become sensitive to the intervention of immune checkpoint inhibitors.Herein,a self-amplified biomimetic nanosystem,mEHGZ,was constructed by encapsulation of epirubicin(EPI),glucose oxidase(Gox)and hemin in ZIF-8 nanoparticles and coating of the nanoparticles with calreticulin(CRT)over-expressed tumor cell mem-brane.EPI acts as an ICD inducer,Gox and hemin medicate the cascade generation of reactive oxygen species(ROS)to strengthen the ICD effect,and CRT-rich membrane as“eat me”signal promote presentation of the released antigens by dendritic cells(DCs)to invoke the tumor-immunity cycle.The biomimetic delivery system displays an amplified ICD effect via Gox oxidation,hydroxyl radical generation and glutathione(GSH)depletion.The induced potent ICD effect promotes DCs maturation and cytotoxic T lymphocytes(CTLs)infiltration,reversing an immunosuppressive tumor microenvironment to an immunoresponsive one.Treatment with the nanosystem in combination with anti-PD-L1 antibody results in distinctive inhibition of tumor growth and lung metastasis,supporting that a potent ICD effect can significantly boost the therapeutic efficacy of the anti-PD-L1 antibody.This self-amplified biomimetic nanoplatform offers a promising means of raising the response rate of immune checkpoint inhibitors.
基金National Natural Science Foundation of China(Nos.41930104,41971330)Hong Kong Research Grants Council General Research Fund(No.152219/18E)。
文摘Map is one of the communication means created by human being.Cartographers have been making efforts on the comparison of maps to natural languages so as to establish a"cartographic language"or"map language".One of such efforts is to adopt the Shannon’s Information Theory originated in digital communication into cartography so as to establish an entropy-based cartographic communication theory.However,success has been very limited although research work had started as early as the mid-1960 s.It is then found that the bottleneck problem was the lack of appropriate measures for the spatial(configurational)information of(graphic and image)maps,as the classic Shannon entropy is only capable of characterizing statistical information but fails to capture the configurational information of(graphic and image)maps.Fortunately,after over 40-year development,some bottleneck problems have been solved.More precisely,generalized Shannon entropies for metric and thematic information of(graphic)maps have been developed and the first feasible solution for computing the Boltzmann entropy of image maps has been invented,which is capable of measuring the spatial information of not only numerical images but also categorical maps.With such progress,it is now feasible to build the"Information Theory of Cartography".In this paper,a framework for such a theory is proposed and some key issues are identified.For these issues,some have already been tackled while others still need efforts.As a result,a research agenda is set for future action.After all these issues are tackled,the theory will become matured so as to become a theoretic basis of cartography.It is expected that the Information Theory of Cartography will play an increasingly important role in the discipline of cartography because more and more researchers have advocated that information is more fundamental than matter and energy.
基金Project supported by the National Key Basic Research Program of China(Grant Nos.2013CBA01603,2016YFA0300600,and 2016YFA0300903)the National Natural Science Foundation of China(Grant Nos.11574005,11774009,11222436,and 11574283)the National Postdoctoral Program for Innovative Talents of China(Grant No.BX201700012)funded by China Postdoctoral Science Foundation.
文摘Being parent materials of two-dimensional (2D) crystals, van der Waals layered materials have received revived interest. In most 2D materials, the interaction between electrons is negligible. Introducing the interaction can give rise to a variety of exotic properties. Here, via intercalating a van der Waals layered compound VS2, we find evidence for electron correlation by extensive magnetic, thermal, electrical, and thermoelectric characterizations. The low temperature Sommerfeld coefficient is 64 mJ·K-2·mol-1 and the Kadowaki-Woods ratio rKW^0.20a0. Both supports an enhancement of the electron correlation. The temperature dependences of the resistivity and thermopower indicate an important role played by the Kondo effect. The Kondo temperature TK is estimated to be around 8 K. Our results suggest intercalation as a potential means to engineer the electron correlation in van der Waals materials, as well as 2D materials.
基金Project supported by the National Key Basic Research Program of China (Grant No. 2020YFA0308800)the National Natural Science Foundation of China (Grant Nos. 11774009 and 12074009)+1 种基金the Natural Science Foundation of Beijing (Grant No. Z200008)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No. 2021008)
文摘The Onsager-Casimir reciprocal relations are a fundamental symmetry of nonequilibrium statistical systems.Here we study an unusual chirality-dependent Hall effect in a tilted Weyl semimetal Co_(3)Sn_(2)S_(2) with broken time-reversal symmetry.It is confirmed that the reciprocal relations are satisfied.Since two Berry curvature effects,an anomalous velocity and a chiral chemical potential,contribute to the observed Hall effect,the reciprocal relations suggest their intriguing connection.
文摘In recent years,there has been a major surge of interest in the development of simulation techniques and strategies for fluid-structure interaction(FSI)problems,mainly driven by a large spectrum of applications in physiology,medical sciences,material sciences,manufacturing processes,and many other engineering disciplines.
文摘The authors regret the incorrect publication of corresponding authors for the article.The corresponding authors have been updated as Hongyan Zhu(hyzhu_hmrrc@126.com)and Kui Luo(luokui@scu.edu.cn),and the same should be updated in the supplementary file as well.
基金This work was supported by National Natural Science Foundation of China(32271445,52073193,and 82202322)National Science and Technology Major Project of China(2023YFB3810004)+2 种基金1·3·5 Project for Disciplines of Excellence,West China Hospital,Sichuan University(ZYJC21013,China)the Sichuan Science and Technology Program(2023NSFSC1592,China),the China Postdoctoral Science Foundation(2021M692255,China)the Post-Doctor Research Project,West China Hospital,Sichuan University(2020HXBH094,China).
文摘Despite the great potential of anti-PD-L1 antibodies for immunotherapy,their low response rate due to an immunosuppressive tumor microenvironment has hampered their application.To address this issue,we constructed a cell membrane-coated nanosystem(mB4S)to reverse an immunosuppressive microenvironment to an immuno-supportive one for strengthening the anti-tumor effect.In this system,Epirubicin(EPI)as an immunogenic cell death(ICD)inducer was coupled to a branched glycopolymer via hydrazone bonds and diABZI as a stimulator of interferon genes(STING)agonist was encapsulated into mB4S.After internalization of mB4S,EPI was acidic-responsively released to induce ICD,which was characterized by an increased level of calreticulin(CRT)exposure and enhanced ATP secretion.Meanwhile,diABZI effectively activated the STING pathway.Treatment with mB4S in combination with an anti-PD-L1 antibody elicited potent immune responses by increasing the ratio of matured dendritic cells(DCs)and CD8+T cells,promoting cytokines secretion,up-regulating M1-like tumor-associated macrophages(TAMs)and down-regulating immunosuppressive myeloid-derived suppressor cells(MDSCs).Therefore,this nanosystem for co-delivery of an ICD inducer and a STING agonist achieved promotion of DCs maturation and CD8+T cells infiltration,creating an immuno-supportive microenvironment,thus potentiating the therapy effect of the anti-PD-L1 antibody in both 4T1 breast and CT26 colon tumor mice.
基金supported by grants from the National Natural Science Foundation of China(31971539)the National Science and Technology Basic Resources Survey Program of China(2019FY101700 and 2021FY100702)the Research Project of Tianjin Normal University(52XB2010).
文摘Understanding the competition and coexistence of flagship carnivores is key to creating strategies for their conservation in the face of global carnivore declines.Although studies exploring the dynamics and competition between tigers(Panthera tigris)and leopards(P.pardus)span decades,there is a lack of understanding regarding the factors that influence their coexistence mechanisms on a broad scale,as well as the drivers determining their exploitative and interference competition.We gathered a comprehensive list of research papers among which 36 papers explored the interspecific interactions between tigers and leopards and tested the influence of biotic and abiotic factors on the coexistence mechanisms along three dimensions using multiple response variables regression models;we also tested the influence of ecological drivers determining the exploitative or interference competition between tigers and leopards.Elevation and ungulate density were the most important predictors in regulating the coexistence mechanisms.Tigers and leopards exhibited more positive relations/higher overlaps as elevation increased in the spatial niche.In addition,they showed a higher dietary overlap in the prey-rich regions.We determined that interference competition between tigers and leopards was less frequently observed in habitats with dense tree cover and homogeneous vegetation structures.Meanwhile,studies with multiple metrics would promote the detection of interference competition.Our study provides new insight into the competitive interactions and coexistence mechanisms of tigers and leopards on a broad scale.Policy-makers and managers should pay more attention to the factors of elevation,prey abundance,and habitat structures for the conservation of tigers and leopards.
基金partially supported by the National Key Research and Development Program of China(2016YFA0600104)supported by donations made by Delos Living LLC,and the Cyrus Tang Foundation+2 种基金supported by the National Natural Science Foundation of China(41471419)Beijing Institute of Urban Planningsupported by the Fundamental Research Funds for the Central Universities(CCNU19TD002).
文摘Land use reflects human activities on land.Urban land use is the highest level human alteration on Earth,and it is rapidly changing due to population increase and urbanization.Urban areas have widespread effects on local hydrology,climate,biodiversity,and food production[1,2].However,maps,that contain knowledge on the distribution,pattern and composition of various land use types in urban areas,are limited to city level.The mapping standard on data sources,methods,land use classification schemes varies from city to city,due to differences in financial input and skills of mapping personnel.To address various national and global environmental challenges caused by urbanization,it is important to have urban land uses at the national and global scales that are derived from the same or consistent data sources with the same or compatible classification systems and mapping methods.This is because,only with urban land use maps produced with similar criteria,consistent environmental policies can be made,and action efforts can be compared and assessed for large scale environmental administration.However,despite of the fact that a number of urban-extent maps exist at global scales[3,4],more detailed urban land use maps do not exist at the same scale.Even at big country or regional levels such as for the United States,China and European Union,consistent land use mapping efforts are rare[5,6](e.g.,https://sdi4apps.eu/open_land_use/).
基金Acknowledgements This work was supported by the National Natural Science Foundation of China (Grant No. 61302084).
文摘In the past few decades, with the growing popularity of compressed sensing (CS) in the signal processing field, the quantization step in CS has received significant attention. Current research generally considers multi-bit quantization. For systems employing quantization with a sufficient number of bits, a sparse signal can be reliably recovered using various CS reconstruction algorithms. Recently, many researchers have begun studying the one- bit quantization case for CS. As an extreme case of CS, one- bit CS preserves only the sign information of measurements, which reduces storage costs and hardware complexity. By treating one-bit measurements as sign constraints, it has been shown that sparse signals can be recovered using certain reconstruction algorithms with a high probability. Based on the merits of one-bit CS, it has been widely applied to many fields, such as radar, source location, spectrum sensing, and wireless sensing network. In this paper, the characteristics of one-bit CS and related works are reviewed. First, the framework of one-bit CS is introduced. Next, we summarize existing reconstruction algorithms. Additionally, some extensions and practical applications of one-bit CS are categorized and discussed. Finally, our conclusions and the further research topics are summarized.
文摘种群密度估计对野生动物的保护和管理至关重要,也是动物生态学和保护生物学备受关注的研究热点,但对大中型兽类种群数量的准确估算一直面临挑战。红外相机是哺乳动物调查中普遍采用的工具,也是克服这一挑战的一种经济有效的方法。目前国际上已有多种方法采用红外相机数据估算不可个体识别动物的种群密度,但相关技术在我国的应用案例较少,本文旨在为国内研究者应用红外相机数据估算动物种群密度提供参考。首先,我们介绍了随机相遇模型(randomencounter model,REM)、随机相遇与停留时间(random encounter and staying time,REST)模型、相机前停留时间(time in front of the camera,TIFC)模型以及红外相机距离取样(cameratrapdistancesampling,CTDS)这四种模型的基本原理和假设;其次,描述了这些模型在野外调查中的技术要点,并给出数据处理与分析的建议;最后,总结了每个模型的数据需求、优点和缺点。虽然我国目前拥有估算种群密度的大量红外相机数据源,但有很多物种的数量尚未知晓,也没有一种方法对所有红外相机数据都是最优的,所以我们建议研究者在了解所研究动物类群的生活史和生态需求基础上,根据模型假设确定合理的采样和分析方案,扩大这些方法的应用,为我国重要物种的保护和保护地建设提供科学指导。