Microorganisms capable of solubilizing and mineralizing phosphorus (P) pools in soils are considered vital in promoting P bioavallability. The study was conducted to screen and isolate inorganic P-solubilizing bacte...Microorganisms capable of solubilizing and mineralizing phosphorus (P) pools in soils are considered vital in promoting P bioavallability. The study was conducted to screen and isolate inorganic P-solubilizing bacteria (IPSB) and organic P-mineralizing bacteria (OPMB) in soils taken from subtropical flooded and temperate non-flooded soils, and to compare inorganic P-solubilizing and organic P-solubilizing abilities between IPSB and OPMB. Ten OPMB strains were isolated and identified as Bacillus cereus and Bacillus megaterium, and five IPSB strains as B. megaterium, Burkholderia caryophyUi, Pseudomonas cichorii, and Pseudomonas syringae. P-solubilizing and -mineralizing abilities of the strains were measured using the methods taking cellular P into account. The IPSB strains exhibited inorganic P-solubilizing abilities ranging between 25.4-41.7 μg P mL^-1 and organic P-mineralizing abilities between 8.2-17.8μg P mL^-1. Each of the OPMB strains also exhibited both solubilizing and mineralizing abilities varying from 4.4 to 26.5 μg P mL^-1 and from 13.8 to 62.8 μg P mL^-1, respectively. For both IPSB and OPMB strains, most of the P mineralized from the organic P source was incorporated into the bacterial cells as cellular P. A significantly negative linear correlation (P 〈 0.05) was found between culture pH and P solubilized from inorganic P by OPMB strains. The results suggested that P solubilization and mineralization could coexist in the same bacterial strain.展开更多
Application of phosphate-solubilizing microorganisms (PSMs) has been reported to increase P uptake and plant growth. However, no information is available regarding the ecological consequences of the inoculation with P...Application of phosphate-solubilizing microorganisms (PSMs) has been reported to increase P uptake and plant growth. However, no information is available regarding the ecological consequences of the inoculation with PSMs. The effect of inoculation with phosphate-solubilizing fungal (PSF) isolates Aspergillus niger P39 and Penicillium oxalicum P66 on the bacterial communities in the rhizospheres of maize (Zea mays L. 'Haiyu 6') and soybean (Glycine max Merr. 'Heinong 35') was examined using culture-dependent methods as well as a culture-independent method, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Compared with the control, the number of culturable microbes for soybean was significantly greater with P39, whereas for maize, the same was significantly greater with P66. In addition, a greater number of microbes were found in the rhizosphere of maize compared with soybean. The fingerprint of DGGE for 16S rDNA indicated that inoculation with PSF also increased bacterial communities, with the P66 treatment having higher numbers of DGGE bands and a higher Shannon-Weaver diversity index compared with P39; the composition of the microbial community was also more complex with the P66 treatment. Overall, complex interactions between plant species and exotic PSMs affected the structure of the bacterial community in the rhizosphere, but plant species were more important in determining the bacterial community structure than the introduction of exotic microorganisms.展开更多
The research isolated phosphorus-soluble bacteria from different parts of ryegrasses and selected 7 bacteria performing better in solbilizing capacity. The test results showed that the capacity of phosphorus-solubiliz...The research isolated phosphorus-soluble bacteria from different parts of ryegrasses and selected 7 bacteria performing better in solbilizing capacity. The test results showed that the capacity of phosphorus-solubilizing tended to be volatile in the range from 135.27 to 187.87 μg/ml and the secreting capacity of IAA was in3.47-24.27 μg/ml. It is believed that Lp59, Lp61, Lp65, Lp69, Lp70 and Lp72 are potential for further development.展开更多
A new approach is proposed in this study for accountable capability improvement based on interpretable capability evaluation using the belief rule base(BRB).Firstly,a capability evaluation model is constructed and opt...A new approach is proposed in this study for accountable capability improvement based on interpretable capability evaluation using the belief rule base(BRB).Firstly,a capability evaluation model is constructed and optimized.Then,the key sub-capabilities are identified by quantitatively calculating the contributions made by each sub-capability to the overall capability.Finally,the overall capability is improved by optimizing the identified key sub-capabilities.The theoretical contributions of the proposed approach are as follows.(i)An interpretable capability evaluation model is constructed by employing BRB which can provide complete access to decision-makers.(ii)Key sub-capabilities are identified according to the quantitative contribution analysis results.(iii)Accountable capability improvement is carried out by only optimizing the identified key sub-capabilities.Case study results show that“Surveillance”,“Positioning”,and“Identification”are identified as key sub-capabilities with a summed contribution of 75.55%in an analytical and deducible fashion based on the interpretable capability evaluation model.As a result,the overall capability is improved by optimizing only the identified key sub-capabilities.The overall capability can be greatly improved from 59.20%to 81.80%with a minimum cost of 397.Furthermore,this paper also investigates how optimizing the BRB with more collected data would affect the evaluation results:only optimizing“Surveillance”and“Positioning”can also improve the overall capability to 81.34%with a cost of 370,which thus validates the efficiency of the proposed approach.展开更多
We systemically investigate optical trapping capability of a kind of tornado waves on Rayleigh particles.Such tornado waves are named as tornado circular Pearcey beams(TCPBs)and produced by combining two circular Pear...We systemically investigate optical trapping capability of a kind of tornado waves on Rayleigh particles.Such tornado waves are named as tornado circular Pearcey beams(TCPBs)and produced by combining two circular Pearcey beams with different radii.Our theoretical exploration delves into various aspects,including the propagation dynamics,energy flux,orbital angular momentum,trapping force,and torque characteristics of TCPBs.The results reveal that the orbital angular momentum,trapping force,and torque of these beams can be finely tuned through the judicious manipulation of their topological charges(l_(1)and l_(2)).Notably,we observe a precise control mechanism wherein the force diminishes with|l_(1)+l_(2)|and|l_(1)-l_(2)|,while the torque exhibits enhancement by decreasing solely with|l_(1)+l_(2)|or increasing with|l_(1)-l_(2)|.These results not only provide quantitative insights into the optical trapping performance of TCPBs but also serve as a valuable reference for the ongoing development of innovative photonic tools.展开更多
Concomitant with the advancement of contemporary medical technology,the significance of perioperative nursing has been increasingly accentuated,necessitating elevated standards for the pedagogy of perioperative nursin...Concomitant with the advancement of contemporary medical technology,the significance of perioperative nursing has been increasingly accentuated,necessitating elevated standards for the pedagogy of perioperative nursing.Presently,the PBL(problem-based learning)pedagogical approach,when integrated with CBL(case-based learning),has garnered considerable interest.An extensive literature review has been conducted to analyze the application of the PBL-CBL fusion in the education of perioperative nursing.Findings indicate that this integrative teaching methodology not only enhances students’theoretical knowledge,practical competencies,and collaborative skills but also contributes to the elevation of teaching quality.In conclusion,the PBL-CBL teaching approach holds immense potential for broader application in perioperative nursing education.Nevertheless,it is imperative to continually refine this combined pedagogical strategy to further enhance the caliber of perioperative nursing instruction and to cultivate a greater number of exceptional nursing professionals in the operating room setting.展开更多
To investigate the process of information technology (IT) impacts on firm competitiveness, an integrated process model of IT impacts on firm competitiveness is brought forward based on the process-oriented view, the...To investigate the process of information technology (IT) impacts on firm competitiveness, an integrated process model of IT impacts on firm competitiveness is brought forward based on the process-oriented view, the resource-based view and the complementary resource view, which is comprised of an IT conversion process, an information system (IS) adoption process, an IS use process and a competition process. The application capability of IT plays the critical role, which determines the efficiency and effectiveness of the aforementioned four processes. The process model of IT impacts on firm competitiveness can also be used to explain why, under what situations and how IT can generate positive organizational outcomes, as well as theoretical bases for further empirical study.展开更多
In order to solve the problem that the current matchmaking methods for semantic web service mainly focus on the matchmaking of IO (inputs, outputs) descriptions which may result in one-sidedness, a description-logic...In order to solve the problem that the current matchmaking methods for semantic web service mainly focus on the matchmaking of IO (inputs, outputs) descriptions which may result in one-sidedness, a description-logic-based IOPE (inputs, outputs, preconditions, effects) description and matchmaking method is proposed for semantic web service. The description logic concept is used to annotate service IO and the description logic assertion is employed to describe service PE(preconditions, effects). TBox subsumption checking is used to measure the subsumption relationship between IO descriptions of service request and advertising; ABox consistency checking is used for checking the logical implication between PE descriptions of service request and advertising. Based upon the logical implication, four kinds of PE matching degrees are proposed to measure and compare the pros and cons of the results of matchmaking. They are the exact, perfect, side-effect and common match. Experiments show that the method has a higher precision rate under the same recall rate compared with the existing method.展开更多
Spinel LiMn2O4 microspheres with durable high rate capability were synthesized by a facile route using spherical MnCO3 precursors as the self-supported templates, combined with the calcinations of LiNO3 at 700 °C...Spinel LiMn2O4 microspheres with durable high rate capability were synthesized by a facile route using spherical MnCO3 precursors as the self-supported templates, combined with the calcinations of LiNO3 at 700 °C for 8 h. The spherical MnCO3 precursors were obtained from the control of the crystallizing process of Mn2+ ions and NH4HCO3 in aqueous solution. The effects of the mole ratio of the raw materials, reaction time, and reaction temperature on the morphology and yield of the MnCO3 were investigated. The as-synthesized MnCO3 and LiMn2O4 microspheres were characterized by powder X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Galvanostatic charge/discharge tests indicate that the spinel LiMn2O4 microspheres deliver a discharge capacity of 90 mA-h/g at 10C rate show good capacity retention capability (75% of their initial capacity after 800 cycles at 10C rate). The durable high rate capability suggests that the as-synthesized LiMn2O4 microspheres are promising cathode materials for high power lithium ion batteries.展开更多
The coexistence theory of slag structure and it's application to calculation of the oxidizing capabilities of slag melts is described. It is shown that the law of mass action can be widely applied to the calculati...The coexistence theory of slag structure and it's application to calculation of the oxidizing capabilities of slag melts is described. It is shown that the law of mass action can be widely applied to the calculation of oxidizing capabilities of slag melts in combination with the coexistence theory of slag structure.For slag melts containing basic oxides FeO and MnO, their oxidizing capabilities can be expressed by N Fe tO =N FeO +6N Fe 2O 3 , while for slag melts containing basic oxides CaO, MgO, etc., in addition to FeO and MnO, their oxidizing capabilities can be given as N Fe tO =N FeO +6N Fe 2O 3 +8N Fe 3O 4 .展开更多
An X-band phased-array meteorological radar (XPAR) was developed in China and will be installed in an airplane to observe precipitation systems for research purposes.In order to examine the observational capability ...An X-band phased-array meteorological radar (XPAR) was developed in China and will be installed in an airplane to observe precipitation systems for research purposes.In order to examine the observational capability of the XPAR and to test the operating mode and calibration before installation in the airplane,a mobile X-band Doppler radar (XDR) and XPAR were installed at the same site to observe convective precipitation events.Nearby S-band operational radar (SA) data were also collected to examine the reflectivity bias of XPAR.An algorithm for quantitative analysis of reflectivity and velocity differences and radar sensitivity of XPAR is presented.The reflectivity and velocity biases of XPAR are examined with SA and XDR.Reflectivity sensitivities,the horizontal and vertical structures of reflectivity by the three radars are compared and analyzed.The results indicated that while the XPRA with different operating modes can capture the main characteristic of 3D structures of precipitation,and the averaged reflectivity differences between XPAR and XDR,and XDR and SA,were 0.4 dB and 6.6 dB on 13 July and-4.5 dB and 5.1 dB on 2 August 2012,respectively.The minimum observed reflectivities at a range of 50 km for XPAR,XDR and SA were about 15.4 dBZ,13.5 dBZ and-3.5 dBZ,respectively.The bias of velocity between XPAR and XDR was negligible.This study provides a possible method for the quantitative comparison of the XPAR data,as well as the sensitivity of reflectivity,calibration,gain and bias introduced by pulse compression.展开更多
Parallel mechanisms(PMs) having the same motion characteristic with a UP kinematic chain(U denotes a universal joint, and P denotes a prismatic joint) are called UP-equivalent PMs. They can be used in many application...Parallel mechanisms(PMs) having the same motion characteristic with a UP kinematic chain(U denotes a universal joint, and P denotes a prismatic joint) are called UP-equivalent PMs. They can be used in many applications, such as machining and milling. However, the existing UP-equivalent PMs suffer from the disadvantages of strict assembly requirements and limited rotational capability. Type synthesis of UP-equivalent PMs with high rotational capability is presented.The special 2 R1 T motion is briefly discussed and the fact that the parallel module of the Exechon robot is not a UP-equivalent PM is disclosed. Using the Lie group theory, the kinematic bonds of limb chains and their mechanical generators are presented. Structural conditions for constructing such UP-equivalent PMs are proposed,which results in numerous new architectures of UP-equivalent PMs. The high rotational capability of the synthesized mechanisms is illustrated by an example. The advantages of no strict assembly requirements and high rotational capability of the newly developed PMs will facilitate their applications in the manufacturing industry.展开更多
The 2000s has witnessed increasing interests in cities′role of innovation in the era of knowledge-based economy.Compared with substantial empirical analysis on the world city hierarchy of innovation,this paper attemp...The 2000s has witnessed increasing interests in cities′role of innovation in the era of knowledge-based economy.Compared with substantial empirical analysis on the world city hierarchy of innovation,this paper attempts to examine the national urban hierarchy of innovation capability in China,in terms of ranking systems,spatial pattern and inter-city linkages of knowledge during the post-reform period since the late 1970s.Based on quantitative analysis such as principal component factor analysis and clustering analysis,this paper identifies the five-tier hierarchy of in-novation,which is headed by Beijing and Shanghai,followed by the capital cities of each province and regional centre cities.The development of China′s urban hierarchy of innovation capability has been driven by such factors as the scale of innovation,scientific scale,innovation potential and innovation environment.The paper further investigates the inter-city linkages of knowledge measured by the number of co-authored papers among the cities.Beijing is positioned in the central position of the knowledge diffusion and knowledge cooperation innovation.More knowledge diffusion among high level cities has occurred than that among the low level cities as well as between the low level cities and high level cities,and provincial capital cities and the regional central cities.展开更多
基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars, the Ministry of Education of the P.R. China.
文摘Microorganisms capable of solubilizing and mineralizing phosphorus (P) pools in soils are considered vital in promoting P bioavallability. The study was conducted to screen and isolate inorganic P-solubilizing bacteria (IPSB) and organic P-mineralizing bacteria (OPMB) in soils taken from subtropical flooded and temperate non-flooded soils, and to compare inorganic P-solubilizing and organic P-solubilizing abilities between IPSB and OPMB. Ten OPMB strains were isolated and identified as Bacillus cereus and Bacillus megaterium, and five IPSB strains as B. megaterium, Burkholderia caryophyUi, Pseudomonas cichorii, and Pseudomonas syringae. P-solubilizing and -mineralizing abilities of the strains were measured using the methods taking cellular P into account. The IPSB strains exhibited inorganic P-solubilizing abilities ranging between 25.4-41.7 μg P mL^-1 and organic P-mineralizing abilities between 8.2-17.8μg P mL^-1. Each of the OPMB strains also exhibited both solubilizing and mineralizing abilities varying from 4.4 to 26.5 μg P mL^-1 and from 13.8 to 62.8 μg P mL^-1, respectively. For both IPSB and OPMB strains, most of the P mineralized from the organic P source was incorporated into the bacterial cells as cellular P. A significantly negative linear correlation (P 〈 0.05) was found between culture pH and P solubilized from inorganic P by OPMB strains. The results suggested that P solubilization and mineralization could coexist in the same bacterial strain.
基金Project supported by the Director Fund of Northeast Institute of Geography and Agroecology, Chinese Academy of Sciencesthe National High Technology Research and Development Program (863 Program) of China (No. 2006AA10Z424).
文摘Application of phosphate-solubilizing microorganisms (PSMs) has been reported to increase P uptake and plant growth. However, no information is available regarding the ecological consequences of the inoculation with PSMs. The effect of inoculation with phosphate-solubilizing fungal (PSF) isolates Aspergillus niger P39 and Penicillium oxalicum P66 on the bacterial communities in the rhizospheres of maize (Zea mays L. 'Haiyu 6') and soybean (Glycine max Merr. 'Heinong 35') was examined using culture-dependent methods as well as a culture-independent method, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Compared with the control, the number of culturable microbes for soybean was significantly greater with P39, whereas for maize, the same was significantly greater with P66. In addition, a greater number of microbes were found in the rhizosphere of maize compared with soybean. The fingerprint of DGGE for 16S rDNA indicated that inoculation with PSF also increased bacterial communities, with the P66 treatment having higher numbers of DGGE bands and a higher Shannon-Weaver diversity index compared with P39; the composition of the microbial community was also more complex with the P66 treatment. Overall, complex interactions between plant species and exotic PSMs affected the structure of the bacterial community in the rhizosphere, but plant species were more important in determining the bacterial community structure than the introduction of exotic microorganisms.
基金Supported by Social Development Projects in Guizhou Province(NY[2011]3104)System Reform Program of Guizhou Province(Z[2012]4005)~~
文摘The research isolated phosphorus-soluble bacteria from different parts of ryegrasses and selected 7 bacteria performing better in solbilizing capacity. The test results showed that the capacity of phosphorus-solubilizing tended to be volatile in the range from 135.27 to 187.87 μg/ml and the secreting capacity of IAA was in3.47-24.27 μg/ml. It is believed that Lp59, Lp61, Lp65, Lp69, Lp70 and Lp72 are potential for further development.
基金supported by the National Natural Science Foundation of China(72471067,72431011,72471238,72231011,62303474,72301286)the Fundamental Research Funds for the Provincial Universities of Zhejiang(GK239909299001-010).
文摘A new approach is proposed in this study for accountable capability improvement based on interpretable capability evaluation using the belief rule base(BRB).Firstly,a capability evaluation model is constructed and optimized.Then,the key sub-capabilities are identified by quantitatively calculating the contributions made by each sub-capability to the overall capability.Finally,the overall capability is improved by optimizing the identified key sub-capabilities.The theoretical contributions of the proposed approach are as follows.(i)An interpretable capability evaluation model is constructed by employing BRB which can provide complete access to decision-makers.(ii)Key sub-capabilities are identified according to the quantitative contribution analysis results.(iii)Accountable capability improvement is carried out by only optimizing the identified key sub-capabilities.Case study results show that“Surveillance”,“Positioning”,and“Identification”are identified as key sub-capabilities with a summed contribution of 75.55%in an analytical and deducible fashion based on the interpretable capability evaluation model.As a result,the overall capability is improved by optimizing only the identified key sub-capabilities.The overall capability can be greatly improved from 59.20%to 81.80%with a minimum cost of 397.Furthermore,this paper also investigates how optimizing the BRB with more collected data would affect the evaluation results:only optimizing“Surveillance”and“Positioning”can also improve the overall capability to 81.34%with a cost of 370,which thus validates the efficiency of the proposed approach.
基金Project supported by the National Natural Science Foundation of China(Grant No.11604058)the Guangxi Natural Science Foundation(Grant Nos.2020GXNSFAA297041 and 2023JJA110112)the Innovation Project of Guangxi Graduate Education(Grant No.YCSW2023083)。
文摘We systemically investigate optical trapping capability of a kind of tornado waves on Rayleigh particles.Such tornado waves are named as tornado circular Pearcey beams(TCPBs)and produced by combining two circular Pearcey beams with different radii.Our theoretical exploration delves into various aspects,including the propagation dynamics,energy flux,orbital angular momentum,trapping force,and torque characteristics of TCPBs.The results reveal that the orbital angular momentum,trapping force,and torque of these beams can be finely tuned through the judicious manipulation of their topological charges(l_(1)and l_(2)).Notably,we observe a precise control mechanism wherein the force diminishes with|l_(1)+l_(2)|and|l_(1)-l_(2)|,while the torque exhibits enhancement by decreasing solely with|l_(1)+l_(2)|or increasing with|l_(1)-l_(2)|.These results not only provide quantitative insights into the optical trapping performance of TCPBs but also serve as a valuable reference for the ongoing development of innovative photonic tools.
文摘Concomitant with the advancement of contemporary medical technology,the significance of perioperative nursing has been increasingly accentuated,necessitating elevated standards for the pedagogy of perioperative nursing.Presently,the PBL(problem-based learning)pedagogical approach,when integrated with CBL(case-based learning),has garnered considerable interest.An extensive literature review has been conducted to analyze the application of the PBL-CBL fusion in the education of perioperative nursing.Findings indicate that this integrative teaching methodology not only enhances students’theoretical knowledge,practical competencies,and collaborative skills but also contributes to the elevation of teaching quality.In conclusion,the PBL-CBL teaching approach holds immense potential for broader application in perioperative nursing education.Nevertheless,it is imperative to continually refine this combined pedagogical strategy to further enhance the caliber of perioperative nursing instruction and to cultivate a greater number of exceptional nursing professionals in the operating room setting.
基金The National Natural Science Foundation of China(No.70671024).
文摘To investigate the process of information technology (IT) impacts on firm competitiveness, an integrated process model of IT impacts on firm competitiveness is brought forward based on the process-oriented view, the resource-based view and the complementary resource view, which is comprised of an IT conversion process, an information system (IS) adoption process, an IS use process and a competition process. The application capability of IT plays the critical role, which determines the efficiency and effectiveness of the aforementioned four processes. The process model of IT impacts on firm competitiveness can also be used to explain why, under what situations and how IT can generate positive organizational outcomes, as well as theoretical bases for further empirical study.
文摘In order to solve the problem that the current matchmaking methods for semantic web service mainly focus on the matchmaking of IO (inputs, outputs) descriptions which may result in one-sidedness, a description-logic-based IOPE (inputs, outputs, preconditions, effects) description and matchmaking method is proposed for semantic web service. The description logic concept is used to annotate service IO and the description logic assertion is employed to describe service PE(preconditions, effects). TBox subsumption checking is used to measure the subsumption relationship between IO descriptions of service request and advertising; ABox consistency checking is used for checking the logical implication between PE descriptions of service request and advertising. Based upon the logical implication, four kinds of PE matching degrees are proposed to measure and compare the pros and cons of the results of matchmaking. They are the exact, perfect, side-effect and common match. Experiments show that the method has a higher precision rate under the same recall rate compared with the existing method.
基金Project(2011M501090) upported by the China Postdoctoral Science FoundationProject(SCUT2012ZZ0042) upported by the Fundamental Research Funds for the Central Universities+1 种基金Project supported by the"SPR-2011"of South China University of TechnologyProject(NRC07/08.EG01)supprted by the Fok Ying Tung Foundation
文摘Spinel LiMn2O4 microspheres with durable high rate capability were synthesized by a facile route using spherical MnCO3 precursors as the self-supported templates, combined with the calcinations of LiNO3 at 700 °C for 8 h. The spherical MnCO3 precursors were obtained from the control of the crystallizing process of Mn2+ ions and NH4HCO3 in aqueous solution. The effects of the mole ratio of the raw materials, reaction time, and reaction temperature on the morphology and yield of the MnCO3 were investigated. The as-synthesized MnCO3 and LiMn2O4 microspheres were characterized by powder X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Galvanostatic charge/discharge tests indicate that the spinel LiMn2O4 microspheres deliver a discharge capacity of 90 mA-h/g at 10C rate show good capacity retention capability (75% of their initial capacity after 800 cycles at 10C rate). The durable high rate capability suggests that the as-synthesized LiMn2O4 microspheres are promising cathode materials for high power lithium ion batteries.
文摘The coexistence theory of slag structure and it's application to calculation of the oxidizing capabilities of slag melts is described. It is shown that the law of mass action can be widely applied to the calculation of oxidizing capabilities of slag melts in combination with the coexistence theory of slag structure.For slag melts containing basic oxides FeO and MnO, their oxidizing capabilities can be expressed by N Fe tO =N FeO +6N Fe 2O 3 , while for slag melts containing basic oxides CaO, MgO, etc., in addition to FeO and MnO, their oxidizing capabilities can be given as N Fe tO =N FeO +6N Fe 2O 3 +8N Fe 3O 4 .
基金funded by National High-Tech Research and Development Projects (863 Grant No. 2007AA061901)+2 种基金the National Key Program for Developing Basic Sciences (Grant No. 2012CB417202)the National Natural Science Foundation of China (Grant No. 41175038)the Public Welfare Meteorological Special Project (Grant No. GYHY201106046)
文摘An X-band phased-array meteorological radar (XPAR) was developed in China and will be installed in an airplane to observe precipitation systems for research purposes.In order to examine the observational capability of the XPAR and to test the operating mode and calibration before installation in the airplane,a mobile X-band Doppler radar (XDR) and XPAR were installed at the same site to observe convective precipitation events.Nearby S-band operational radar (SA) data were also collected to examine the reflectivity bias of XPAR.An algorithm for quantitative analysis of reflectivity and velocity differences and radar sensitivity of XPAR is presented.The reflectivity and velocity biases of XPAR are examined with SA and XDR.Reflectivity sensitivities,the horizontal and vertical structures of reflectivity by the three radars are compared and analyzed.The results indicated that while the XPRA with different operating modes can capture the main characteristic of 3D structures of precipitation,and the averaged reflectivity differences between XPAR and XDR,and XDR and SA,were 0.4 dB and 6.6 dB on 13 July and-4.5 dB and 5.1 dB on 2 August 2012,respectively.The minimum observed reflectivities at a range of 50 km for XPAR,XDR and SA were about 15.4 dBZ,13.5 dBZ and-3.5 dBZ,respectively.The bias of velocity between XPAR and XDR was negligible.This study provides a possible method for the quantitative comparison of the XPAR data,as well as the sensitivity of reflectivity,calibration,gain and bias introduced by pulse compression.
基金Supported by National Natural Science Foundation of China (Grant Nos.51525504,51475431)Zhejiang Provincial Natural Science Foundation of China (Grant No.LZ14E050005)Science Foundation of Zhejiang Sci-Tech University,China (Grant No.16022091-Y)
文摘Parallel mechanisms(PMs) having the same motion characteristic with a UP kinematic chain(U denotes a universal joint, and P denotes a prismatic joint) are called UP-equivalent PMs. They can be used in many applications, such as machining and milling. However, the existing UP-equivalent PMs suffer from the disadvantages of strict assembly requirements and limited rotational capability. Type synthesis of UP-equivalent PMs with high rotational capability is presented.The special 2 R1 T motion is briefly discussed and the fact that the parallel module of the Exechon robot is not a UP-equivalent PM is disclosed. Using the Lie group theory, the kinematic bonds of limb chains and their mechanical generators are presented. Structural conditions for constructing such UP-equivalent PMs are proposed,which results in numerous new architectures of UP-equivalent PMs. The high rotational capability of the synthesized mechanisms is illustrated by an example. The advantages of no strict assembly requirements and high rotational capability of the newly developed PMs will facilitate their applications in the manufacturing industry.
基金Under the auspices of National Natural Science Foundation of China(No.41071103)Guangdong Natural Science Foundation(No.9151051501000061)+1 种基金Foundation of Humanities and Social Sciences(No.10ZGXM79006)Foundation of Guangzhou Education Bureau(No.10A030)
文摘The 2000s has witnessed increasing interests in cities′role of innovation in the era of knowledge-based economy.Compared with substantial empirical analysis on the world city hierarchy of innovation,this paper attempts to examine the national urban hierarchy of innovation capability in China,in terms of ranking systems,spatial pattern and inter-city linkages of knowledge during the post-reform period since the late 1970s.Based on quantitative analysis such as principal component factor analysis and clustering analysis,this paper identifies the five-tier hierarchy of in-novation,which is headed by Beijing and Shanghai,followed by the capital cities of each province and regional centre cities.The development of China′s urban hierarchy of innovation capability has been driven by such factors as the scale of innovation,scientific scale,innovation potential and innovation environment.The paper further investigates the inter-city linkages of knowledge measured by the number of co-authored papers among the cities.Beijing is positioned in the central position of the knowledge diffusion and knowledge cooperation innovation.More knowledge diffusion among high level cities has occurred than that among the low level cities as well as between the low level cities and high level cities,and provincial capital cities and the regional central cities.