The key activity to build semantic web is to build ontologies. But today, the theory and methodology of ontology construction is still far from ready. This paper proposed a theoretical framework for massive knowledge ...The key activity to build semantic web is to build ontologies. But today, the theory and methodology of ontology construction is still far from ready. This paper proposed a theoretical framework for massive knowledge management- the knowledge domain framework （KDF）, and introduces an integrated development environment （IDE） named large-scale ontology development environment （LODE）, which implements the proposed theoretical framework. We also compared LODE with other popular ontology development environments in this paper. The practice of using LODE on management and development of agriculture ontologies shows that knowledge domain framework can handle the development activities of large scale ontologies. Application studies based on the described briefly. principle of knowledge domain framework and LODE was展开更多
Density-based algorithm for discovering clusters in large spatial databases with noise(DBSCAN) is a classic kind of density-based spatial clustering algorithm and is widely applied in several aspects due to good perfo...Density-based algorithm for discovering clusters in large spatial databases with noise(DBSCAN) is a classic kind of density-based spatial clustering algorithm and is widely applied in several aspects due to good performance in capturing arbitrary shapes and detecting outliers. However, in practice, datasets are always too massive to fit the serial DBSCAN. And a new parallel algorithm-Parallel DBSCAN(PDBSCAN) was proposed to solve the problem which DBSCAN faced. The proposed parallel algorithm bases on MapReduce mechanism. The usage of parallel mechanism in the algorithm focuses on region query and candidate queue processing which needed substantive computation resources. As a result, PDBSCAN is scalable for large-scale dataset clustering and is extremely suitable for applications in E-Commence, especially for recommendation.展开更多
At present,there is a contradiction between the rapid growth of the number of patents declared and authorized by agricultural scientific research institutions and the decline of the efficiency of invention patents yea...At present,there is a contradiction between the rapid growth of the number of patents declared and authorized by agricultural scientific research institutions and the decline of the efficiency of invention patents year by year,and the low conversion rate of patents.This paper discusses the patent application quantity,authorization quantity and patent efficiency of the Tropical Crops Genetic Resources Institute,Chinese Academy of Tropical Agricultural Sciences,analyzes the present situation of its work and the main problems existing in patent management,and puts forward the relevant suggestions.展开更多
At the end of 20th Century, the electric energy became a new indicator of world civilization. The era of electricity also put his mark on the Romanian alveolus of civilization. The paper deals with an analysis of the ...At the end of 20th Century, the electric energy became a new indicator of world civilization. The era of electricity also put his mark on the Romanian alveolus of civilization. The paper deals with an analysis of the scientific researches and applications which express the results of works of eminent scientists and engineers in electro-techniques and related domains, in Romania, in the first decade of interwar period 1919-1929. The scientific activities developed in many domains of Science are sustained by the significant technical progress in Romania, in this short but relevant period of Tempus in which, in Europe and in other parts of Civitas Terra, was peace.展开更多
Playing games is one of the important contents of preschool education, and the application of scientific fun games in preschool education can not only bring fun to children, but also transfer knowledge and cultivate c...Playing games is one of the important contents of preschool education, and the application of scientific fun games in preschool education can not only bring fun to children, but also transfer knowledge and cultivate childrens emotions with the help of games. Therefore, the rational use of scientific fun games is of great significance. For preschool teachers, it is necessary to correctly view the development of scientific fun games, and give scientific education and guidance to children in the games, so as to give full play to the practical value of scientific fun games.展开更多
This paper discusses the digital application and benefit analysis of building information model(BIM)technology in the large-scale comprehensive development project of the Guangxi headquarters base.The project covers a...This paper discusses the digital application and benefit analysis of building information model(BIM)technology in the large-scale comprehensive development project of the Guangxi headquarters base.The project covers a total area of 92,100 square meters,with a total construction area of 379,700 square meters,including a variety of architectural forms.Through three-dimensional modeling and simulation analysis,BIM technology significantly enhances the design quality and efficiency,shortens the design cycle by about 20%,and promotes the collaboration and integration of project management,improving the management efficiency by about 25%.During the construction phase,the collision detection and four-dimensional visual management functions of BIM technology have improved construction efficiency by about 15%and saved the cost by about 10%.In addition,BIM technology has promoted green building and sustainable development,achieved the dual improvement of technical and economic indicators and social and economic benefits,set an example for enterprises in digital transformation,and opened up new market businesses.展开更多
Chinese learning in primary school is an important stage to develop students' intelligence, cultivate their comprehensive ability to use language and accumulate Chinese knowledge. Incentive education is a further ...Chinese learning in primary school is an important stage to develop students' intelligence, cultivate their comprehensive ability to use language and accumulate Chinese knowledge. Incentive education is a further requirement of our country's quality education concept for primary school Chinese education at the stage of compulsory education. Scientific incentive education can not only motivate students' learning enthusiasm, but also enable students to establish self-confidence and enhance willpower. This paper discusses the application of scientific incentive education in Chinese teaching in primary schools for reference.展开更多
This paper firstly introduced theoretical background of the Activity-Based Costing(ABC). Then,it analyzed necessity,extension resistance and difficulty of ABC approach in agri-scientific research institutions. Finally...This paper firstly introduced theoretical background of the Activity-Based Costing(ABC). Then,it analyzed necessity,extension resistance and difficulty of ABC approach in agri-scientific research institutions. Finally,it came up with some recommendations for scientifically learning and steadily promoting ABC method in agri-scientific research field.展开更多
This study examined the development of technician teams on large-scale instrument platforms in universities,using the State Key Laboratory of Natural and Biomimetic Drugs in the Peking University School of Pharmaceuti...This study examined the development of technician teams on large-scale instrument platforms in universities,using the State Key Laboratory of Natural and Biomimetic Drugs in the Peking University School of Pharmaceutical Sciences as a case study.Data were collected through questionnaire surveys and interviews conducted in 2017,followed by a questionnaire survey in 2023,offering both subjective and objective insights.The evolution of the platform’s technician team over the past 5 years was analyzed,highlighting key experiences and identifying ongoing challenges.Recommendations to enhance technician team development include recruiting skilled faculty,clearly defining job responsibilities,and refining the assessment and incentive systems.展开更多
Based on the evolution of farming revolution in Fengyan aiming to create a healthier and more beautiful human existence and a harmonious coexistence with nature, this study introduced Fenlong green agriculture, which ...Based on the evolution of farming revolution in Fengyan aiming to create a healthier and more beautiful human existence and a harmonious coexistence with nature, this study introduced Fenlong green agriculture, which had the characteristics of natural yield increase of more than 10% with zero fertilization, and yield increase of 10%-30%, quality improvement of 5% and doubled land water holding capacity with the conventional fertilization in over 20 crops in more than 20 provinces, and significant reforming efficiency on salinized land and grassland; for the first time made a comprehensive description of high efficient application of Fenlong green modern agriculture to explore natural resources, realizing the sustainable develop- ment of quality improvement, yield increase and efficiency enhancement; for the first time clarified the scientific basis and theoretical system of the green efficient mod- ern agricultural technique-Fenlong cultivation, as well as the basic connotations and concepts of Fenlong cultivation, green efficient modern agricultural technical system; created a new model of efficient modern agricultural production and new technology system, and 6 major technical projects like cultivated land improvement to increase yield and transformation of salinized land and grassland, which could play a role in relieving the climatic disasters like haze, transformation of farmland with medium to low yield as well as the construction of high standard farmland, sucrose industry and ＂One Road One Belt＂ strategy; for the first time proposed Fenlong cultivation as the ＂China technology card＂ in China and even the whole world, so as to make people understand the particular significance of this technology to green develop- ment, which could benefit the future generations.展开更多
Rubik’s Cube is a widely popular mechanical puzzle that has attracted attention around the world because of its unique characteristics. As a classic brain-training toy well known to the public, Rubik’s Cube was used...Rubik’s Cube is a widely popular mechanical puzzle that has attracted attention around the world because of its unique characteristics. As a classic brain-training toy well known to the public, Rubik’s Cube was used for scientific research and technology development by many scholars. This paper provides a basic understanding of the Rubik’s Cube and shows its mechanical art from the aspects of origin and development, characteristics, research status and especially its mechanical engineering design, as well as making a vision for the application in mechanism. First, the invention and origin of Rubik’s Cube are presented, and then the special characteristics of the cube itself are analyzed.After that, the present researches of Rubik’s Cube are reviewed in various disciplines at home and abroad, including the researches of Rubik’s Cube scientific metaphors, reduction algorithms, characteristic applications, and mechanism issues. Finally, the applications and prospects of Rubik’s Cube in the field of mechanism are discussed.展开更多
In recent years,the usage,management and benefit of large-scale scientific research instruments and equipment in scientific research institutes have been a leading issue in the management of scientific research instit...In recent years,the usage,management and benefit of large-scale scientific research instruments and equipment in scientific research institutes have been a leading issue in the management of scientific research institutes.Within the scope of equipment budget,it is necessary for each equipment acquisition team to conduct a round of communication,coordination and negotiation with suppliers in order to improve the cost performance of equipment procurement and maximize the performance index to meet the needs of scientific research.By introducing the practical experience of the State Key Laboratory in purchasing imported equipment and managing large-scale instruments,this paper probes into the management process of the imported large-scale scientific research tax-free equipment of scientific research institutes,and explores the system and methods to guarantee and improve the efficiency of large-scale instruments in scientific research institutes from the aspects of policy,funds and technology.展开更多
With an increasing urgent demand for fast recovery routing mechanisms in large-scale networks,minimizing network disruption caused by network failure has become critical.However,a large number of relevant studies have...With an increasing urgent demand for fast recovery routing mechanisms in large-scale networks,minimizing network disruption caused by network failure has become critical.However,a large number of relevant studies have shown that network failures occur on the Internet inevitably and frequently.The current routing protocols deployed on the Internet adopt the reconvergence mechanism to cope with network failures.During the reconvergence process,the packets may be lost because of inconsistent routing information,which reduces the network’s availability greatly and affects the Internet service provider’s(ISP’s)service quality and reputation seriously.Therefore,improving network availability has become an urgent problem.As such,the Internet Engineering Task Force suggests the use of downstream path criterion(DC)to address all single-link failure scenarios.However,existing methods for implementing DC schemes are time consuming,require a large amount of router CPU resources,and may deteriorate router capability.Thus,the computation overhead introduced by existing DC schemes is significant,especially in large-scale networks.Therefore,this study proposes an efficient intra-domain routing protection algorithm(ERPA)in large-scale networks.Theoretical analysis indicates that the time complexity of ERPA is less than that of constructing a shortest path tree.Experimental results show that ERPA can reduce the computation overhead significantly compared with the existing algorithms while offering the same network availability as DC.展开更多
Superhydrophobic coating has been widely studied for its great applicational potential, such as for corrosion protection of magnesium alloys while it has been restrained by expensive materials, sophisticated preparati...Superhydrophobic coating has been widely studied for its great applicational potential, such as for corrosion protection of magnesium alloys while it has been restrained by expensive materials, sophisticated preparation process and infirm rough structures. In this study, the electrochemical method was adopted by using a two-electrode system for rapid hydrophobic modification to obtain superhydrophobic kaolin.By mixing the modified superhydrophobic kaolin with commercial epoxy resin and polydimethylsiloxane glue, a paint can be formed and easily used on various substrates for preparation of superhydrophobic coating via spraying method. The influence factors on wettability of the modified kaolin and the mixing ratio of each component of the coating were explored. Also, the wettability, durability and anticorrosion of the prepared coating were evaluated comprehensively. The coating was able to maintain superhydrophobic after immersed in HCl solution at pH 1, the NaOH solution at pH 14, and 3.5 wt.% NaCl solution for 16, 21, 30 days, respectively. In addition, the coating exhibited 4A grade adhesion, high hydrophobicity after abraded for 200 cycles on a 600-mesh sandpaper with 100 g weight, and 99.86% anticorrosion efficiency after soaked in 3.5 wt.% NaCl solution for 20 days, demonstrating a good robustness and anti-corrosion property. Furthermore, the coating showed good transparency, flexibility and was easy to make in a large scale by the spraying method, which is of great significance to promote the practical application of superhydrophobic coatings and the anticorrosion Mg alloys.展开更多
To solve large-scale optimization problems,Fragrance coefficient and variant Particle Swarm local search Butterfly Optimization Algorithm(FPSBOA)is proposed.In the position update stage of Butterfly Optimization Algor...To solve large-scale optimization problems,Fragrance coefficient and variant Particle Swarm local search Butterfly Optimization Algorithm(FPSBOA)is proposed.In the position update stage of Butterfly Optimization Algorithm(BOA),the fragrance coefficient is designed to balance the exploration and exploitation of BOA.The variant particle swarm local search strategy is proposed to improve the local search ability of the current optimal butterfly and prevent the algorithm from falling into local optimality.192000-dimensional functions and 201000-dimensional CEC 2010 large-scale functions are used to verify FPSBOA for complex large-scale optimization problems.The experimental results are statistically analyzed by Friedman test and Wilcoxon rank-sum test.All attained results demonstrated that FPSBOA can better solve more challenging scientific and industrial real-world problems with thousands of variables.Finally,four mechanical engineering problems and one ten-dimensional process synthesis and design problem are applied to FPSBOA,which shows FPSBOA has the feasibility and effectiveness in real-world application problems.展开更多
Stem cells (SCs), the undifferentiated biological cells, have the infinite capacity to self-renew and the pluripotent ability to differentiate. SCs and their derived products offer great promise for biomedical applica...Stem cells (SCs), the undifferentiated biological cells, have the infinite capacity to self-renew and the pluripotent ability to differentiate. SCs and their derived products offer great promise for biomedical applications such as cell therapy, tissue engineering, regenerative medicine and drug screening. However, the clinical applications of SCs require a large amount of SCs with high quality and the number of SCs from their tissue resources is very limited. Large-scale expansion is needed to generate homogeneous SCs with good biological characteristics for clinical application. This necessitates a bioreactor system to provide controllable and stable conditions for stem cell (SC) culture. Traditional methods of bioreactor for maintenance and expansion of cells rely on two-dimensional (2-D) culture techniques, leading to loss self-renewal ability and differentiation capacity upon long-term culture. New approaches for SC expansion with bioreactor employ three-dimensional (3-D) cell growth to mimic their environment in vivo. In this review, we summarize the application of bioreactors in SC culture.展开更多
We sketch Friedrich Ackermann’s research program following the concept of Imre Lakatos,with some historical key developments in the theory and application of aerotriangulation and image matching.The research program,...We sketch Friedrich Ackermann’s research program following the concept of Imre Lakatos,with some historical key developments in the theory and application of aerotriangulation and image matching.The research program,with its core being statistical estimation theory,has decisively influenced photogrammetry since the 60s,is still fully alive,and a challenge for today’s methods of image interpretation.We describe(1)Lakatos’concept of a scientific research program,with its negative and positive heuristics and(2)Ackermann’s research program,clearly made explicit in his PhD,with its mathematical model,the ability to predict theoretical precision and reliability,the potential of analyzing rigorous and approximate method,and the role of testing.The development of aerotriangulation,later augmented by image matching techniques,is closely connected to Ackermann’s successful attempts to integrate basic research and practical applications.展开更多
The article introduces the main practices and achievements of the Environment and Plant Protection Institute of Chinese Academy of Tropical Agricultural Sciences in promoting the sharing of large-scale instruments and...The article introduces the main practices and achievements of the Environment and Plant Protection Institute of Chinese Academy of Tropical Agricultural Sciences in promoting the sharing of large-scale instruments and equipment in recent years,analyzes the existing problems in the management system,management team,assessment incentives and maintenance guarantee,and proposes improvement measures and suggestions from aspects of improving the sharing management system,strengthening management team building,strengthening sharing assessment and incentives,improving maintenance capabilities and expanding external publicity,to further improve the sharing management of large-scale instruments and equipment.展开更多
The numerical quadrature methods for dealing with the problems of singular and near-singular integrals caused by Burton-Miller method are proposed, by which the conventional and fast multipole BEMs （boundary element ...The numerical quadrature methods for dealing with the problems of singular and near-singular integrals caused by Burton-Miller method are proposed, by which the conventional and fast multipole BEMs （boundary element methods） for 3D acoustic problems based on constant elements are improved. To solve the problem of singular integrals, a Hadamard finite-part integral method is presented, which is a simplified combination of the methods proposed by Kirkup and Wolf. The problem of near-singular integrals is overcome by the simple method of polar transformation and the more complex method of PART （Projection and Angular ＆ Radial Transformation）. The effectiveness of these methods for solving the singular and near-singular problems is validated through comparing with the results computed by the analytical method and/or the commercial software LMS Virtual.Lab. In addition, the influence of the near-singular integral problem on the computational precisions is analyzed by computing the errors relative to the exact solution. The computational complexities of the conventional and fast multipole BEM are analyzed and compared through numerical computations. A large-scale acoustic scattering problem, whose degree of freedoms is about 340,000, is implemented successfully. The results show that, the near singularity is primarily introduced by the hyper-singular kernel, and has great influences on the precision of the solution. The precision of fast multipole BEM is the same as conventional BEM, but the computational complexities are much lower.展开更多
Under the influence of a one-dimensional stationary outfield with the equilibrium between kinetic and potential energy produced by it,a modified Sch(?)rdinger equation in the form i((?)ψ/(?)t)t=a (?)~2ψ/ax^2-ib (?),...Under the influence of a one-dimensional stationary outfield with the equilibrium between kinetic and potential energy produced by it,a modified Sch(?)rdinger equation in the form i((?)ψ/(?)t)t=a (?)~2ψ/ax^2-ib (?),where b=b_o(?)T/(?)x,is used to describe the behavior of the probability wave on the six-month departure charts at the 500 hPa level.It is found that C=2πa/L-b_o(?)T/ax and when L→∞,then C= -b_o(?)T/(?)x,where C is wave velocity,a and b are constants,and L is wavelength.The motion direction of probability waves is against the outfield temperature gradient,and their velocity is related to the absolute value of temperature gradient.The motion of waves shrinks in heat sinks and expands in heat sources,which have been verified in practice.Finally the six-month departure probability wave and the modified Sch(?)rdinger equation are used in the MOS predictions of temperature and rainfall in spring-summer 1981-1985 in Jilin Province and the accuracy for trend predictions is equal to 80%.展开更多
基金supported by the Key Technology R&D Program of China during the 12th Five-Year Plan period:Super-Class Scientific and Technical Thesaurus and Ontology Construction Faced the Foreign Scientific and Technical Literature (2011BAH10B01)
文摘The key activity to build semantic web is to build ontologies. But today, the theory and methodology of ontology construction is still far from ready. This paper proposed a theoretical framework for massive knowledge management- the knowledge domain framework （KDF）, and introduces an integrated development environment （IDE） named large-scale ontology development environment （LODE）, which implements the proposed theoretical framework. We also compared LODE with other popular ontology development environments in this paper. The practice of using LODE on management and development of agriculture ontologies shows that knowledge domain framework can handle the development activities of large scale ontologies. Application studies based on the described briefly. principle of knowledge domain framework and LODE was
基金National Natural Science Foundations of China( No. 61070101,No. 60875029,No. 61175048)
文摘Density-based algorithm for discovering clusters in large spatial databases with noise(DBSCAN) is a classic kind of density-based spatial clustering algorithm and is widely applied in several aspects due to good performance in capturing arbitrary shapes and detecting outliers. However, in practice, datasets are always too massive to fit the serial DBSCAN. And a new parallel algorithm-Parallel DBSCAN(PDBSCAN) was proposed to solve the problem which DBSCAN faced. The proposed parallel algorithm bases on MapReduce mechanism. The usage of parallel mechanism in the algorithm focuses on region query and candidate queue processing which needed substantive computation resources. As a result, PDBSCAN is scalable for large-scale dataset clustering and is extremely suitable for applications in E-Commence, especially for recommendation.
文摘At present,there is a contradiction between the rapid growth of the number of patents declared and authorized by agricultural scientific research institutions and the decline of the efficiency of invention patents year by year,and the low conversion rate of patents.This paper discusses the patent application quantity,authorization quantity and patent efficiency of the Tropical Crops Genetic Resources Institute,Chinese Academy of Tropical Agricultural Sciences,analyzes the present situation of its work and the main problems existing in patent management,and puts forward the relevant suggestions.
文摘At the end of 20th Century, the electric energy became a new indicator of world civilization. The era of electricity also put his mark on the Romanian alveolus of civilization. The paper deals with an analysis of the scientific researches and applications which express the results of works of eminent scientists and engineers in electro-techniques and related domains, in Romania, in the first decade of interwar period 1919-1929. The scientific activities developed in many domains of Science are sustained by the significant technical progress in Romania, in this short but relevant period of Tempus in which, in Europe and in other parts of Civitas Terra, was peace.
文摘Playing games is one of the important contents of preschool education, and the application of scientific fun games in preschool education can not only bring fun to children, but also transfer knowledge and cultivate childrens emotions with the help of games. Therefore, the rational use of scientific fun games is of great significance. For preschool teachers, it is necessary to correctly view the development of scientific fun games, and give scientific education and guidance to children in the games, so as to give full play to the practical value of scientific fun games.
基金The 2023 Guangxi University Young and Middle-Aged Teachers’Scientific Research Basic Ability Improvement Project“Research on Seismic Performance of Prefabricated CFST Column-SRC Beam Composite Joints”(2023KY1204)The 2023 Guangxi Vocational Education Teaching Reform Research Project“Research and Practice on the Cultivation of Digital Talents in Prefabricated Buildings in the Context of Deepening the Integration of Industry and Education”(GXGZJG2023B052)The 2022 Guangxi Polytechnic of Construction School-Level Teaching Innovation Team Project“Prefabricated and Intelligent Teaching Innovation Team”(Gui Jian Yuan Ren[2022]No.15)。
文摘This paper discusses the digital application and benefit analysis of building information model(BIM)technology in the large-scale comprehensive development project of the Guangxi headquarters base.The project covers a total area of 92,100 square meters,with a total construction area of 379,700 square meters,including a variety of architectural forms.Through three-dimensional modeling and simulation analysis,BIM technology significantly enhances the design quality and efficiency,shortens the design cycle by about 20%,and promotes the collaboration and integration of project management,improving the management efficiency by about 25%.During the construction phase,the collision detection and four-dimensional visual management functions of BIM technology have improved construction efficiency by about 15%and saved the cost by about 10%.In addition,BIM technology has promoted green building and sustainable development,achieved the dual improvement of technical and economic indicators and social and economic benefits,set an example for enterprises in digital transformation,and opened up new market businesses.
文摘Chinese learning in primary school is an important stage to develop students' intelligence, cultivate their comprehensive ability to use language and accumulate Chinese knowledge. Incentive education is a further requirement of our country's quality education concept for primary school Chinese education at the stage of compulsory education. Scientific incentive education can not only motivate students' learning enthusiasm, but also enable students to establish self-confidence and enhance willpower. This paper discusses the application of scientific incentive education in Chinese teaching in primary schools for reference.
基金Supported by Project of Hubei Provincial Soft Science Research Plan(2011DEA023)
文摘This paper firstly introduced theoretical background of the Activity-Based Costing(ABC). Then,it analyzed necessity,extension resistance and difficulty of ABC approach in agri-scientific research institutions. Finally,it came up with some recommendations for scientifically learning and steadily promoting ABC method in agri-scientific research field.
文摘This study examined the development of technician teams on large-scale instrument platforms in universities,using the State Key Laboratory of Natural and Biomimetic Drugs in the Peking University School of Pharmaceutical Sciences as a case study.Data were collected through questionnaire surveys and interviews conducted in 2017,followed by a questionnaire survey in 2023,offering both subjective and objective insights.The evolution of the platform’s technician team over the past 5 years was analyzed,highlighting key experiences and identifying ongoing challenges.Recommendations to enhance technician team development include recruiting skilled faculty,clearly defining job responsibilities,and refining the assessment and incentive systems.
文摘Based on the evolution of farming revolution in Fengyan aiming to create a healthier and more beautiful human existence and a harmonious coexistence with nature, this study introduced Fenlong green agriculture, which had the characteristics of natural yield increase of more than 10% with zero fertilization, and yield increase of 10%-30%, quality improvement of 5% and doubled land water holding capacity with the conventional fertilization in over 20 crops in more than 20 provinces, and significant reforming efficiency on salinized land and grassland; for the first time made a comprehensive description of high efficient application of Fenlong green modern agriculture to explore natural resources, realizing the sustainable develop- ment of quality improvement, yield increase and efficiency enhancement; for the first time clarified the scientific basis and theoretical system of the green efficient mod- ern agricultural technique-Fenlong cultivation, as well as the basic connotations and concepts of Fenlong cultivation, green efficient modern agricultural technical system; created a new model of efficient modern agricultural production and new technology system, and 6 major technical projects like cultivated land improvement to increase yield and transformation of salinized land and grassland, which could play a role in relieving the climatic disasters like haze, transformation of farmland with medium to low yield as well as the construction of high standard farmland, sucrose industry and ＂One Road One Belt＂ strategy; for the first time proposed Fenlong cultivation as the ＂China technology card＂ in China and even the whole world, so as to make people understand the particular significance of this technology to green develop- ment, which could benefit the future generations.
基金Supported by National Natural Science Foundation of China(Grant No.51775473)Hebei Provincial Natural Science Foundation of China(Grant No.E2018203140)Hebei Provincial System Construction Project of Guide Program for Technology Innovation(Grant No.18241905D)
文摘Rubik’s Cube is a widely popular mechanical puzzle that has attracted attention around the world because of its unique characteristics. As a classic brain-training toy well known to the public, Rubik’s Cube was used for scientific research and technology development by many scholars. This paper provides a basic understanding of the Rubik’s Cube and shows its mechanical art from the aspects of origin and development, characteristics, research status and especially its mechanical engineering design, as well as making a vision for the application in mechanism. First, the invention and origin of Rubik’s Cube are presented, and then the special characteristics of the cube itself are analyzed.After that, the present researches of Rubik’s Cube are reviewed in various disciplines at home and abroad, including the researches of Rubik’s Cube scientific metaphors, reduction algorithms, characteristic applications, and mechanism issues. Finally, the applications and prospects of Rubik’s Cube in the field of mechanism are discussed.
文摘In recent years,the usage,management and benefit of large-scale scientific research instruments and equipment in scientific research institutes have been a leading issue in the management of scientific research institutes.Within the scope of equipment budget,it is necessary for each equipment acquisition team to conduct a round of communication,coordination and negotiation with suppliers in order to improve the cost performance of equipment procurement and maximize the performance index to meet the needs of scientific research.By introducing the practical experience of the State Key Laboratory in purchasing imported equipment and managing large-scale instruments,this paper probes into the management process of the imported large-scale scientific research tax-free equipment of scientific research institutes,and explores the system and methods to guarantee and improve the efficiency of large-scale instruments in scientific research institutes from the aspects of policy,funds and technology.
基金the National Natural Science Foundation of China(No.61702315)the Key R&D program(international science and technology cooperation project)of Shanxi Province China(No.201903D421003)the National Key Research and Development Program of China(No.2018YFB1800401).
文摘With an increasing urgent demand for fast recovery routing mechanisms in large-scale networks,minimizing network disruption caused by network failure has become critical.However,a large number of relevant studies have shown that network failures occur on the Internet inevitably and frequently.The current routing protocols deployed on the Internet adopt the reconvergence mechanism to cope with network failures.During the reconvergence process,the packets may be lost because of inconsistent routing information,which reduces the network’s availability greatly and affects the Internet service provider’s(ISP’s)service quality and reputation seriously.Therefore,improving network availability has become an urgent problem.As such,the Internet Engineering Task Force suggests the use of downstream path criterion(DC)to address all single-link failure scenarios.However,existing methods for implementing DC schemes are time consuming,require a large amount of router CPU resources,and may deteriorate router capability.Thus,the computation overhead introduced by existing DC schemes is significant,especially in large-scale networks.Therefore,this study proposes an efficient intra-domain routing protection algorithm(ERPA)in large-scale networks.Theoretical analysis indicates that the time complexity of ERPA is less than that of constructing a shortest path tree.Experimental results show that ERPA can reduce the computation overhead significantly compared with the existing algorithms while offering the same network availability as DC.
基金the financial support of the National Natural Science Foundation of China (Grant No. 21978182)。
文摘Superhydrophobic coating has been widely studied for its great applicational potential, such as for corrosion protection of magnesium alloys while it has been restrained by expensive materials, sophisticated preparation process and infirm rough structures. In this study, the electrochemical method was adopted by using a two-electrode system for rapid hydrophobic modification to obtain superhydrophobic kaolin.By mixing the modified superhydrophobic kaolin with commercial epoxy resin and polydimethylsiloxane glue, a paint can be formed and easily used on various substrates for preparation of superhydrophobic coating via spraying method. The influence factors on wettability of the modified kaolin and the mixing ratio of each component of the coating were explored. Also, the wettability, durability and anticorrosion of the prepared coating were evaluated comprehensively. The coating was able to maintain superhydrophobic after immersed in HCl solution at pH 1, the NaOH solution at pH 14, and 3.5 wt.% NaCl solution for 16, 21, 30 days, respectively. In addition, the coating exhibited 4A grade adhesion, high hydrophobicity after abraded for 200 cycles on a 600-mesh sandpaper with 100 g weight, and 99.86% anticorrosion efficiency after soaked in 3.5 wt.% NaCl solution for 20 days, demonstrating a good robustness and anti-corrosion property. Furthermore, the coating showed good transparency, flexibility and was easy to make in a large scale by the spraying method, which is of great significance to promote the practical application of superhydrophobic coatings and the anticorrosion Mg alloys.
基金funded by the National Natural Science Foundation of China(No.72104069)the Science and Technology Department of Henan Province,China(No.182102310886 and 162102110109)the Postgraduate Meritocracy Scheme,hina(No.SYL19060145).
文摘To solve large-scale optimization problems,Fragrance coefficient and variant Particle Swarm local search Butterfly Optimization Algorithm(FPSBOA)is proposed.In the position update stage of Butterfly Optimization Algorithm(BOA),the fragrance coefficient is designed to balance the exploration and exploitation of BOA.The variant particle swarm local search strategy is proposed to improve the local search ability of the current optimal butterfly and prevent the algorithm from falling into local optimality.192000-dimensional functions and 201000-dimensional CEC 2010 large-scale functions are used to verify FPSBOA for complex large-scale optimization problems.The experimental results are statistically analyzed by Friedman test and Wilcoxon rank-sum test.All attained results demonstrated that FPSBOA can better solve more challenging scientific and industrial real-world problems with thousands of variables.Finally,four mechanical engineering problems and one ten-dimensional process synthesis and design problem are applied to FPSBOA,which shows FPSBOA has the feasibility and effectiveness in real-world application problems.
文摘Stem cells (SCs), the undifferentiated biological cells, have the infinite capacity to self-renew and the pluripotent ability to differentiate. SCs and their derived products offer great promise for biomedical applications such as cell therapy, tissue engineering, regenerative medicine and drug screening. However, the clinical applications of SCs require a large amount of SCs with high quality and the number of SCs from their tissue resources is very limited. Large-scale expansion is needed to generate homogeneous SCs with good biological characteristics for clinical application. This necessitates a bioreactor system to provide controllable and stable conditions for stem cell (SC) culture. Traditional methods of bioreactor for maintenance and expansion of cells rely on two-dimensional (2-D) culture techniques, leading to loss self-renewal ability and differentiation capacity upon long-term culture. New approaches for SC expansion with bioreactor employ three-dimensional (3-D) cell growth to mimic their environment in vivo. In this review, we summarize the application of bioreactors in SC culture.
文摘We sketch Friedrich Ackermann’s research program following the concept of Imre Lakatos,with some historical key developments in the theory and application of aerotriangulation and image matching.The research program,with its core being statistical estimation theory,has decisively influenced photogrammetry since the 60s,is still fully alive,and a challenge for today’s methods of image interpretation.We describe(1)Lakatos’concept of a scientific research program,with its negative and positive heuristics and(2)Ackermann’s research program,clearly made explicit in his PhD,with its mathematical model,the ability to predict theoretical precision and reliability,the potential of analyzing rigorous and approximate method,and the role of testing.The development of aerotriangulation,later augmented by image matching techniques,is closely connected to Ackermann’s successful attempts to integrate basic research and practical applications.
文摘The article introduces the main practices and achievements of the Environment and Plant Protection Institute of Chinese Academy of Tropical Agricultural Sciences in promoting the sharing of large-scale instruments and equipment in recent years,analyzes the existing problems in the management system,management team,assessment incentives and maintenance guarantee,and proposes improvement measures and suggestions from aspects of improving the sharing management system,strengthening management team building,strengthening sharing assessment and incentives,improving maintenance capabilities and expanding external publicity,to further improve the sharing management of large-scale instruments and equipment.
基金supported by the National Natural Science Foundation of China(11304344,11404364)the Project of Hubei Provincial Department of Education(D20141803)+1 种基金the Natural Science Foundation of Hubei Province(2014CFB378)the Doctoral Scientific Research Foundation of Hubei University of Automotive Technology(BK201604)
文摘The numerical quadrature methods for dealing with the problems of singular and near-singular integrals caused by Burton-Miller method are proposed, by which the conventional and fast multipole BEMs （boundary element methods） for 3D acoustic problems based on constant elements are improved. To solve the problem of singular integrals, a Hadamard finite-part integral method is presented, which is a simplified combination of the methods proposed by Kirkup and Wolf. The problem of near-singular integrals is overcome by the simple method of polar transformation and the more complex method of PART （Projection and Angular ＆ Radial Transformation）. The effectiveness of these methods for solving the singular and near-singular problems is validated through comparing with the results computed by the analytical method and/or the commercial software LMS Virtual.Lab. In addition, the influence of the near-singular integral problem on the computational precisions is analyzed by computing the errors relative to the exact solution. The computational complexities of the conventional and fast multipole BEM are analyzed and compared through numerical computations. A large-scale acoustic scattering problem, whose degree of freedoms is about 340,000, is implemented successfully. The results show that, the near singularity is primarily introduced by the hyper-singular kernel, and has great influences on the precision of the solution. The precision of fast multipole BEM is the same as conventional BEM, but the computational complexities are much lower.
文摘Under the influence of a one-dimensional stationary outfield with the equilibrium between kinetic and potential energy produced by it,a modified Sch(?)rdinger equation in the form i((?)ψ/(?)t)t=a (?)~2ψ/ax^2-ib (?),where b=b_o(?)T/(?)x,is used to describe the behavior of the probability wave on the six-month departure charts at the 500 hPa level.It is found that C=2πa/L-b_o(?)T/ax and when L→∞,then C= -b_o(?)T/(?)x,where C is wave velocity,a and b are constants,and L is wavelength.The motion direction of probability waves is against the outfield temperature gradient,and their velocity is related to the absolute value of temperature gradient.The motion of waves shrinks in heat sinks and expands in heat sources,which have been verified in practice.Finally the six-month departure probability wave and the modified Sch(?)rdinger equation are used in the MOS predictions of temperature and rainfall in spring-summer 1981-1985 in Jilin Province and the accuracy for trend predictions is equal to 80%.
