The high-pressure phase diagram of the Nb-Ti binary system at 0 K is explored by systematic crystal structure prediction.The results highlight a novel niobium-rich bcc phase,Nb_(7)Ti,which is the only dynamically stab...The high-pressure phase diagram of the Nb-Ti binary system at 0 K is explored by systematic crystal structure prediction.The results highlight a novel niobium-rich bcc phase,Nb_(7)Ti,which is the only dynamically stable ordered Nb-Ti compound under ambient pressure.Extensive first-principles calculations have provided insights into the electronic structure,bonding and superconducting properties of Nb_(7)Ti.The superconducting transition temperature(T_(c))for Nb_(7)Ti at ambient pressure is estimated within the framework of BCS theory to be about 17.5 K,which is significantly higher—nearly double—that of the widely utilized NbTi alloy.Furthermore,the results unveil that the high T_(c) is mainly attributed to the unique ordered lattice along with the strong electron-phonon coupling driven by interatomic interactions at mid-frequency and phonon softening induced by low-frequency Fermi surface nesting.Valuable insights are provided for the subsequent synthesis of application-oriented superconductors at low pressure.展开更多
The behavioral responses of birds to urban environments are crucial for their ability to thrive within city landscapes.Various urban birds have demonstrated the capacity to exploit artificial structures as nesting sit...The behavioral responses of birds to urban environments are crucial for their ability to thrive within city landscapes.Various urban birds have demonstrated the capacity to exploit artificial structures as nesting sites due to the limited availability of natural options.This review examines the current state of urban bird nesting behaviors on manmade structures and highlights directions for future research.Nest types frequently observed on these structures include woven,cavity,ground,and mud nests.These adaptive behaviors increase nesting opportunities and improve reproductive success,although they may heighten vulnerability to ecological traps.Proximity to human habitats can promote conservation awareness but also presents potential economic and health-related challenges.Therefore,applying diverse strategies is essential for effectively managing and protecting nests on man-made structures across various circumstances.There is also a need for thorough,long-term studies on the ecological and evolutionary impacts of nest building on artificial structures and the mechanisms influencing nestsite selection.Furthermore,exploring innovative approaches that combine policy implementation and citizen science will be vital for advancing human-bird coexistence.展开更多
Five prediction experiments are carried out with two typhoons in 1992 using a limited -arca primitiveequations and two-way interactive model in a movable ,nested mesh. The result indicates good agreementin terms of mo...Five prediction experiments are carried out with two typhoons in 1992 using a limited -arca primitiveequations and two-way interactive model in a movable ,nested mesh. The result indicates good agreementin terms of motion between the prediction and observation. Studying the asymmetric structure in the cas-es selected, a close link is uncovered between the temporal evolutions of the structure and the track of motion in a tropical cyclone. Understanding of real asymmetric structure will help to improve the skill offorecasting tropical cyclones.展开更多
For the purpose of improving the mechanical performance indices of uncertain structures with interval parameters and ensure their robustness when fluctuating under interval parameters, a constrained interval robust op...For the purpose of improving the mechanical performance indices of uncertain structures with interval parameters and ensure their robustness when fluctuating under interval parameters, a constrained interval robust optimization model is constructed with both the center and halfwidth of the most important mechanical performance index described as objective functions and the other requirements on the mechanical performance indices described as constraint functions. To locate the optimal solution of objective and feasibility robustness, a new concept of interval violation vector and its calculation formulae corresponding to different constraint functions are proposed. The math?ematical formulae for calculating the feasibility and objective robustness indices and the robustness?based preferential guidelines are proposed for directly ranking various design vectors, which is realized by an algorithm integrating Kriging and nested genetic algorithm. The validity of the proposed method and its superiority to present interval optimization approaches are demonstrated by a numerical example. The robust optimization of the upper beam in a high?speed press with interval material properties demonstrated the applicability and effectiveness of the proposed method in engineering.展开更多
It is shown that any multicriteria problem can be represented by a hierarchical system of criteria. Individual properties of the object (alternative) are evaluated at the bottom level of the system, using a criteria v...It is shown that any multicriteria problem can be represented by a hierarchical system of criteria. Individual properties of the object (alternative) are evaluated at the bottom level of the system, using a criteria vector. A composition mechanism is used to evaluate the object as a whole at the top level. The problem is solved by the method of nested scalar convolutions of vector-valued criteria. The methodology of the problem solving is based on the complementarity principle by N. Bohr and the theorem of incompleteness by K. G?del. An example is presented that helps the reader digest some of the intricacies in the methodology.展开更多
With Zn(NO3)2·6H2O and NaOH as starting materials, a novel nest-like ZnO nanostructure was successfully synthesized by a solvo-thermal method. The products were characterized by X-ray diffraction, photoluminescen...With Zn(NO3)2·6H2O and NaOH as starting materials, a novel nest-like ZnO nanostructure was successfully synthesized by a solvo-thermal method. The products were characterized by X-ray diffraction, photoluminescence and scanning electron microscopy. The growth mechanism of the nest-like ZnO was discussed. The results show that the as-synthesized samples have a wurtzite structure, with a weak UV emission at about 395 nm, a green emission at around 557 nm and a blue-green emission at 453 nm. SEM investigation reveals that the growth route of the nest-like ZnO can be considered involving three stages: nano-sized ZnO sheet can be firstly achieved, then outspreads quickly and increasingly becomes a long fishbone-like strip with many branch sheets, and finally these sheets curl into a nest-like structure.展开更多
Background: Nest construction is a key element of avian reproductive behaviour and the result is often a complex structure that is used for incubation of eggs, which represents an extended phenotype. It is known that ...Background: Nest construction is a key element of avian reproductive behaviour and the result is often a complex structure that is used for incubation of eggs, which represents an extended phenotype. It is known that nest construction is a plastic behaviour but the extent to which plasticity is observed in a single species with a wide geographical distribution is largely unknown. This study sought to better understand variation in nest size and composition across a very wide geographical area. The hypothesis suggested that location would affect size but not composition of nests of the European Pied Flycatcher (Ficedula hypoleuca). Methods: Nests and reproductive data were collected from seventeen study sites, spread over 6° of latitude and 3.3° of longitude on the island of Great Britain. Dimensions of nests were measured before they were deconstructed to determine the masses and types materials used in the outer nest and the cup lining. Results: Geographical variation was observed in base thickness of nests but not many other dimensions. Nests varied in composition but were mainly made of leaf, moss, bark, grass, root and fern. Moss was used more to the north and east of the study area compared with more leaf mass towards the south and west. The species of leaf and bark used in the nests varied between geographical locations. Additionally, the use of leaves or bark from a particular tree species did not reflect the incidence of the tree species in the immediate territory. Conclusions: This study showed that nest composition was affected by geographical location over a wide area. Variation between nests at each location was high and so it was concluded that differences in nest composition reflect individual selection of materials but evidence is such that it remains unclear whether this is deliberate to fulfil a specific role in the nest, or simply opportunistic with birds simply picking up materials with the appropriate characteristics as they find them outside their nestbox.展开更多
Artificial nest boxes are placed to attract birds to nest and breed in a specific location,and they are widely used in avian ecology research and in the attraction of insectivorous birds.There is evidence that artific...Artificial nest boxes are placed to attract birds to nest and breed in a specific location,and they are widely used in avian ecology research and in the attraction of insectivorous birds.There is evidence that artificial nest boxes can adversely affect breeding fitness but no great focus has been placed on this issue by researchers.Therefore,we retrieved 321 research papers regarding artificial nest boxes published from 2003 to 2022 and used the'Biblioshiny'program to extract and integrate keywords;we then summarized the adverse effects of artificial nest boxes on avian breeding success.The studies highlighted many drawbacks and misuses in the designing and placement of nest boxes;furthermore,bird attraction was decreased by their inappropriate selection,thus reducing breeding success.Regarding nest box production,there were shortcomings in the construction material,color,smell,and structural design of the boxes used.Nest boxes were also placed at inappropriate densities,locations,orientations,heights,and managed incorrectly.Finally,we propose suggestions for more efficient and safer artificial nest boxes for future use in avian ecology research and bird conservation.展开更多
Purpose： In this contribution we try to find new indicators to measure characteristics of a finn＇s patents and their influence on a company＇s profits. Design/methodology/approach： We realize that patentevaluation ...Purpose： In this contribution we try to find new indicators to measure characteristics of a finn＇s patents and their influence on a company＇s profits. Design/methodology/approach： We realize that patentevaluation and influence on a company＇s profits is a complicated issue requiring different perspectives. For this reason we design two types of structural h-indices, derived from the International Patent Classification （IPC）. In a case study we apply not only basic statistics but also a nested case-control methodology. Findings： The resulting indicator values based on a large dataset （19,080 patents in total） from the pharmaceutical industry show that the new structural indices are significantly correlated with a firm＇s profits. Research limitations： The new structural index and the synthetic structural index have just been applied in one case study in the pharmaceutical industry. Practical implications： Our study suggests useful implications for patentometric studies and leads to suggestions for different sized firms to include a healthy research and development （R＆D） policy management. The structural h-index can be used to gauge the profits resulting from the innovative performance of a firm＇s patent portfolio. Originality/value： Traditionally, the breadth and depth of patents of a firm and their citations are considered separately. This approach, however, does not provide an integrated insight in the major characteristics of a firm＇s patents. The Sh（Y） index, proposed in our investigation, can reflect a firm＇s innovation activities, its technological breadth, and its influence in an integrated way.展开更多
A kind of novel muhiband antenna with square-nested fractal is proposed and designed, including printed monopole antenna and dipole antenna, which are nested with a series of similar square elements. The antennas can ...A kind of novel muhiband antenna with square-nested fractal is proposed and designed, including printed monopole antenna and dipole antenna, which are nested with a series of similar square elements. The antennas can synchronously operate in multiple frequencies, covering the four required frequencies, 2.4GHz/ 3.5GHz/5.2GHz/5.8GHz, for WLAN/WiMAX application. The antenna surface currents are simulated by CST MWS, a three-dimension full-wave electromagnetic simulator, and the multiband operating mechanism has been explained from analysis of the simulation results. Then the models of the two proposed antennas fed by coplanar waveguide （monopole antenna） and balanced microstripline （dipole antenna）, respectively, have been obtained. Finally, prototypes of the two antennas have been manufactured and measured in anechoic chamber. The results well match the simulation results, which verifies the feasibility of design idea. Moreover, these antennas are miniature and the design idea can be easily applied into other types of nested structure, the features of which make the Proposed antennas have promising application in muhiband fields.展开更多
燕窝自古以来一直被视为一种名贵的滋补佳品,而糖蛋白是其主要的活性成分之一,具有抗氧化、抗炎、抗病毒、提高免疫力等多种功能特性,近年来备受关注。本文首先从可视化和知识图谱角度,以CNKI中国学术期刊全文数据库和Web of Science数...燕窝自古以来一直被视为一种名贵的滋补佳品,而糖蛋白是其主要的活性成分之一,具有抗氧化、抗炎、抗病毒、提高免疫力等多种功能特性,近年来备受关注。本文首先从可视化和知识图谱角度,以CNKI中国学术期刊全文数据库和Web of Science数据库为基础,借助VOSviewer分析软件,分析燕窝国内外的研究现状、热点和趋势。概述燕窝糖蛋白的提取方法、分离纯化技术、结构表征研究现状,并对燕窝糖蛋白增强免疫力、抗氧化、抗病毒、神经保护、提高记忆力、降血糖、调节肠道菌群等作用进行总结。旨在为燕窝糖蛋白作为功能性食品原材料及品质分级关键指标提供科学参考。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12122405,12274169,and 11574109)the Fundamental Research Funds for the Central Universities。
文摘The high-pressure phase diagram of the Nb-Ti binary system at 0 K is explored by systematic crystal structure prediction.The results highlight a novel niobium-rich bcc phase,Nb_(7)Ti,which is the only dynamically stable ordered Nb-Ti compound under ambient pressure.Extensive first-principles calculations have provided insights into the electronic structure,bonding and superconducting properties of Nb_(7)Ti.The superconducting transition temperature(T_(c))for Nb_(7)Ti at ambient pressure is estimated within the framework of BCS theory to be about 17.5 K,which is significantly higher—nearly double—that of the widely utilized NbTi alloy.Furthermore,the results unveil that the high T_(c) is mainly attributed to the unique ordered lattice along with the strong electron-phonon coupling driven by interatomic interactions at mid-frequency and phonon softening induced by low-frequency Fermi surface nesting.Valuable insights are provided for the subsequent synthesis of application-oriented superconductors at low pressure.
基金supported by the National Key Research and Development Program(2022YFC3202104)National Natural Science Foundation of China(32101237)Natural Science Foundation of Jiangsu Province(BK20211151)。
文摘The behavioral responses of birds to urban environments are crucial for their ability to thrive within city landscapes.Various urban birds have demonstrated the capacity to exploit artificial structures as nesting sites due to the limited availability of natural options.This review examines the current state of urban bird nesting behaviors on manmade structures and highlights directions for future research.Nest types frequently observed on these structures include woven,cavity,ground,and mud nests.These adaptive behaviors increase nesting opportunities and improve reproductive success,although they may heighten vulnerability to ecological traps.Proximity to human habitats can promote conservation awareness but also presents potential economic and health-related challenges.Therefore,applying diverse strategies is essential for effectively managing and protecting nests on man-made structures across various circumstances.There is also a need for thorough,long-term studies on the ecological and evolutionary impacts of nest building on artificial structures and the mechanisms influencing nestsite selection.Furthermore,exploring innovative approaches that combine policy implementation and citizen science will be vital for advancing human-bird coexistence.
文摘Five prediction experiments are carried out with two typhoons in 1992 using a limited -arca primitiveequations and two-way interactive model in a movable ,nested mesh. The result indicates good agreementin terms of motion between the prediction and observation. Studying the asymmetric structure in the cas-es selected, a close link is uncovered between the temporal evolutions of the structure and the track of motion in a tropical cyclone. Understanding of real asymmetric structure will help to improve the skill offorecasting tropical cyclones.
基金Supported by National Natural Science Foundation of China(Grant Nos.51775491,51475417,U1608256,51405433)
文摘For the purpose of improving the mechanical performance indices of uncertain structures with interval parameters and ensure their robustness when fluctuating under interval parameters, a constrained interval robust optimization model is constructed with both the center and halfwidth of the most important mechanical performance index described as objective functions and the other requirements on the mechanical performance indices described as constraint functions. To locate the optimal solution of objective and feasibility robustness, a new concept of interval violation vector and its calculation formulae corresponding to different constraint functions are proposed. The math?ematical formulae for calculating the feasibility and objective robustness indices and the robustness?based preferential guidelines are proposed for directly ranking various design vectors, which is realized by an algorithm integrating Kriging and nested genetic algorithm. The validity of the proposed method and its superiority to present interval optimization approaches are demonstrated by a numerical example. The robust optimization of the upper beam in a high?speed press with interval material properties demonstrated the applicability and effectiveness of the proposed method in engineering.
文摘It is shown that any multicriteria problem can be represented by a hierarchical system of criteria. Individual properties of the object (alternative) are evaluated at the bottom level of the system, using a criteria vector. A composition mechanism is used to evaluate the object as a whole at the top level. The problem is solved by the method of nested scalar convolutions of vector-valued criteria. The methodology of the problem solving is based on the complementarity principle by N. Bohr and the theorem of incompleteness by K. G?del. An example is presented that helps the reader digest some of the intricacies in the methodology.
基金Projects(09JCYBJC04200, 05yfJMTC 12900) supported by the Natural Science Foundation of Tianjin, China
文摘With Zn(NO3)2·6H2O and NaOH as starting materials, a novel nest-like ZnO nanostructure was successfully synthesized by a solvo-thermal method. The products were characterized by X-ray diffraction, photoluminescence and scanning electron microscopy. The growth mechanism of the nest-like ZnO was discussed. The results show that the as-synthesized samples have a wurtzite structure, with a weak UV emission at about 395 nm, a green emission at around 557 nm and a blue-green emission at 453 nm. SEM investigation reveals that the growth route of the nest-like ZnO can be considered involving three stages: nano-sized ZnO sheet can be firstly achieved, then outspreads quickly and increasingly becomes a long fishbone-like strip with many branch sheets, and finally these sheets curl into a nest-like structure.
文摘Background: Nest construction is a key element of avian reproductive behaviour and the result is often a complex structure that is used for incubation of eggs, which represents an extended phenotype. It is known that nest construction is a plastic behaviour but the extent to which plasticity is observed in a single species with a wide geographical distribution is largely unknown. This study sought to better understand variation in nest size and composition across a very wide geographical area. The hypothesis suggested that location would affect size but not composition of nests of the European Pied Flycatcher (Ficedula hypoleuca). Methods: Nests and reproductive data were collected from seventeen study sites, spread over 6° of latitude and 3.3° of longitude on the island of Great Britain. Dimensions of nests were measured before they were deconstructed to determine the masses and types materials used in the outer nest and the cup lining. Results: Geographical variation was observed in base thickness of nests but not many other dimensions. Nests varied in composition but were mainly made of leaf, moss, bark, grass, root and fern. Moss was used more to the north and east of the study area compared with more leaf mass towards the south and west. The species of leaf and bark used in the nests varied between geographical locations. Additionally, the use of leaves or bark from a particular tree species did not reflect the incidence of the tree species in the immediate territory. Conclusions: This study showed that nest composition was affected by geographical location over a wide area. Variation between nests at each location was high and so it was concluded that differences in nest composition reflect individual selection of materials but evidence is such that it remains unclear whether this is deliberate to fulfil a specific role in the nest, or simply opportunistic with birds simply picking up materials with the appropriate characteristics as they find them outside their nestbox.
基金supported by the National Natural Science Foundation of China(Grant No.32170485,31501867)the Fundamental Research Funds for the Central Universities(Grant No.2572022BE02)。
文摘Artificial nest boxes are placed to attract birds to nest and breed in a specific location,and they are widely used in avian ecology research and in the attraction of insectivorous birds.There is evidence that artificial nest boxes can adversely affect breeding fitness but no great focus has been placed on this issue by researchers.Therefore,we retrieved 321 research papers regarding artificial nest boxes published from 2003 to 2022 and used the'Biblioshiny'program to extract and integrate keywords;we then summarized the adverse effects of artificial nest boxes on avian breeding success.The studies highlighted many drawbacks and misuses in the designing and placement of nest boxes;furthermore,bird attraction was decreased by their inappropriate selection,thus reducing breeding success.Regarding nest box production,there were shortcomings in the construction material,color,smell,and structural design of the boxes used.Nest boxes were also placed at inappropriate densities,locations,orientations,heights,and managed incorrectly.Finally,we propose suggestions for more efficient and safer artificial nest boxes for future use in avian ecology research and bird conservation.
基金supported by the National Natural Science Foundation of China(Grant Nos:71173185 and 71573225)
文摘Purpose： In this contribution we try to find new indicators to measure characteristics of a finn＇s patents and their influence on a company＇s profits. Design/methodology/approach： We realize that patentevaluation and influence on a company＇s profits is a complicated issue requiring different perspectives. For this reason we design two types of structural h-indices, derived from the International Patent Classification （IPC）. In a case study we apply not only basic statistics but also a nested case-control methodology. Findings： The resulting indicator values based on a large dataset （19,080 patents in total） from the pharmaceutical industry show that the new structural indices are significantly correlated with a firm＇s profits. Research limitations： The new structural index and the synthetic structural index have just been applied in one case study in the pharmaceutical industry. Practical implications： Our study suggests useful implications for patentometric studies and leads to suggestions for different sized firms to include a healthy research and development （R＆D） policy management. The structural h-index can be used to gauge the profits resulting from the innovative performance of a firm＇s patent portfolio. Originality/value： Traditionally, the breadth and depth of patents of a firm and their citations are considered separately. This approach, however, does not provide an integrated insight in the major characteristics of a firm＇s patents. The Sh（Y） index, proposed in our investigation, can reflect a firm＇s innovation activities, its technological breadth, and its influence in an integrated way.
基金Sponsored by the Fundamental Research Funds for the Central Universities (Grant No. HIT. NSRIF. 2010096)the Heilongjiang Post-Doctorial Fi-nancial Assistance (Grant No. LBH-Z09187)
文摘A kind of novel muhiband antenna with square-nested fractal is proposed and designed, including printed monopole antenna and dipole antenna, which are nested with a series of similar square elements. The antennas can synchronously operate in multiple frequencies, covering the four required frequencies, 2.4GHz/ 3.5GHz/5.2GHz/5.8GHz, for WLAN/WiMAX application. The antenna surface currents are simulated by CST MWS, a three-dimension full-wave electromagnetic simulator, and the multiband operating mechanism has been explained from analysis of the simulation results. Then the models of the two proposed antennas fed by coplanar waveguide （monopole antenna） and balanced microstripline （dipole antenna）, respectively, have been obtained. Finally, prototypes of the two antennas have been manufactured and measured in anechoic chamber. The results well match the simulation results, which verifies the feasibility of design idea. Moreover, these antennas are miniature and the design idea can be easily applied into other types of nested structure, the features of which make the Proposed antennas have promising application in muhiband fields.
文摘燕窝自古以来一直被视为一种名贵的滋补佳品,而糖蛋白是其主要的活性成分之一,具有抗氧化、抗炎、抗病毒、提高免疫力等多种功能特性,近年来备受关注。本文首先从可视化和知识图谱角度,以CNKI中国学术期刊全文数据库和Web of Science数据库为基础,借助VOSviewer分析软件,分析燕窝国内外的研究现状、热点和趋势。概述燕窝糖蛋白的提取方法、分离纯化技术、结构表征研究现状,并对燕窝糖蛋白增强免疫力、抗氧化、抗病毒、神经保护、提高记忆力、降血糖、调节肠道菌群等作用进行总结。旨在为燕窝糖蛋白作为功能性食品原材料及品质分级关键指标提供科学参考。
