In this paper, the CE/SE method is developed to simulate the two- and three-dimensional flow-field of Pulse Detonation Engine (PDE). The conservation equations with stiff source terms for chemical reaction are solved ...In this paper, the CE/SE method is developed to simulate the two- and three-dimensional flow-field of Pulse Detonation Engine (PDE). The conservation equations with stiff source terms for chemical reaction are solved in two steps. The detailed analysis of computational results of a PDE with a single detonation tube and a PDE with five detonation tubes are given in this paper. Complex wave systems are observed inside and outside a PDE. For a PDE with 5 detonation tubes, there is a big bow shock produced from a number of little shocks near the open ends of tubes. A lot of vortexes interact with shocks and a large expansion wave propagates forward and backward with respect to the PDE in a semi-oval shape.展开更多
Vegetation or land cover maps have been made directly or indirectly available for the entire territory of China. The certainties and uncertainties of land cover statistics were analyzed by comparing three data sources...Vegetation or land cover maps have been made directly or indirectly available for the entire territory of China. The certainties and uncertainties of land cover statistics were analyzed by comparing three data sources: China's Vegetation Map, IGPB DISCover, and University of Maryland Product. Great similarities in the statistics of 7 aggregated land cover types were found among the three data sources, particularly between the two global land cover maps. The per pixel agreement between any 2 of 3 maps was between 38.0%—51.4%; the per pixel agreement among all three maps was only 27.1%. Certainties were found in regions where vegetation types are typical and human land use practice is relatively homogenous; the uncertainties occurred to either vegetation transition zones or regions where land cover types and land use practice are relatively diversified. Systematic and multidisciplinary efforts are necessary to promote accurate mapping of nationwide land cover types in China. Intensive efforts should be made in regions where uncertainties of land cover information are found.展开更多
Natural regeneration of tree species is important to the sustainability of native forest ecosystems in the temperate zone of north- east China. This study compared the densities and heights of seedlings and the divers...Natural regeneration of tree species is important to the sustainability of native forest ecosystems in the temperate zone of north- east China. This study compared the densities and heights of seedlings and the diversities of shrubs and herbs on three sites of logging op- erations: log-skidding trails (LST), logging gaps (LG) and log landing sites (LLS). Sites undisturbed by logging gaps operations were sam- pled as control. The species, counts and height of tree seedlings and the species, counts, height and percentage coverage of shrubs and herbs were recorded in the field. The highest density and greatest height of regeneration trees were observed at LG and LST. The effects of LST on the densities of broadleaved trees were greater than those of coniferous trees. The difference in seedling density between LLS and control was significant (p=0.05). There was no significant difference in average seedling height for all the tree species between the disturbed sites and control. There were more shrub and herb species at the disturbed sites than at control. The diversity of understory plants at LG was the highest among all the sites. LST and LLS were different in shrub diversity, so were LLS and control. Both LG and LLS were different from control in herb diversity. Active measures need to be taken on the operation sites to protect the coniferous trees and the diversities of under- story plants for sustaining the structure and composition of the broadleaved-Korean pine mixed forest on Changbai Mountain of China. Since different operation sites have different effects on different tree species, site-dependent actions must be taken to assure the regeneration of ecologically important tree species.展开更多
The objective of this research is to identify DNA markers linked to QTLs controlling FHB resistance in wheat, and to compare if the QTLs in three resistant germplasm are common. Three wheat recombinant inbred populati...The objective of this research is to identify DNA markers linked to QTLs controlling FHB resistance in wheat, and to compare if the QTLs in three resistant germplasm are common. Three wheat recombinant inbred populations derived from the crosses between Alondra (susceptible) and three resistant lines, Wangshuibai, Sumai3, and 894037, respectively, were evaluated for reaction to Fusarium graminearum in greenhouse and in field conditions over years. Simple sequence repeat (SSR) markers were screened in the populations and regression analysis was used to identify markers associated with FHB resistance. For the population of Sumai3 (resistant)/Alondra (susceptible), which contained 161 recombinant inbred lines, two SSR markers located on chromosome 3B were found to be associated with resistant QTLs. These markers accounted for 2.66.7% phenotypic variation. The 894037 (resistant)/Alondra (susceptible) population was consisted of 147 recombinant inbred lines. A total of 59 SSR primers were screened in this population and seven of them were linked to resistant QTLs. The QTLs on chromosome 3B accounted for 47.4% phenotypic variation. Minor QTLs were also located on 2D, 7A, 6B, and 4B chromosomes, and the resistant QTLs on 2D and 4B chromosomes were from Alondra. The last population of 80 recombinant inbred lines was from the cross Wangshuibai (resistant)/Alondra (susceptible). A total of 120 SSR primers were screened in this population, eight of which were linked to resistant QTLs. These markers were located on 3B, 4B, 2D, 4D, and 6D (uncertain) chromosomes respectively. The QTLs on chromosome 3B accounted for 8.927.0% phenotypic variation. The resistant QTLs on chromosomes 4B and 6D (uncertain) were from Alondra. The other QTLs were from Wangshuibai. SSR markers linked to resistant QTLs on chromosome 3B were found in all three populations, and account for higher phenotypic variation. So these markers should be useful in marker assisted selection.展开更多
Three kinds of plant growth regulators, gibberellinA 4/7 （GA 4/7 ）, 6-benzylaminopurine （BA）, and chlormequat chloride （CCC）, were evaluated for their ability to promote strobilus and cone production in a Chines...Three kinds of plant growth regulators, gibberellinA 4/7 （GA 4/7 ）, 6-benzylaminopurine （BA）, and chlormequat chloride （CCC）, were evaluated for their ability to promote strobilus and cone production in a Chinese pine （Pinus tabuliformis Carr.） clonal seed orchard. Treatments （0, 250, 500, or 1000 mg L -1 ） were applied during three periods （June- July, July-August and August-September） in 2005. Of the three plant growth regulators, GA 4/7 was the best for promoting flower and cone production. Trees sprayed with GA 4/7 （500 mg L -1 ） from June to September had significantly more female strobili and immature cones than controls and other treatments （p≤0.0001）. The best time to apply GA 4/7 was in June. BA at 500 mg L -1 significantly increased female flower and immature cone production, compared to other treatments and controls （p≤0.0001）, while promotion of male strobili was unchanged. Chlormequat chloride at 1000 mg L -1 significantly increased the number of male strobili, compared to the other treatments （p≤0.0001）. Spraying CCC at500 mg L -1 significantly increased the number of female strobili, compared to controls （p0.05）, but it had no effect on immature cone production （p0.05）. These results are important for improving seed production and seed orchard management of Chinese pine.展开更多
A quantum key distribution scheme for quantum cryptographic network is proposed, which is implemented physically by the Greenberger-Home-Zeilinger (GHZ) triplet state. Its security is guaranteed by the correlation of ...A quantum key distribution scheme for quantum cryptographic network is proposed, which is implemented physically by the Greenberger-Home-Zeilinger (GHZ) triplet state. Its security is guaranteed by the correlation of the GHZ triplet state, results show this protocol is unconditionally secure. The performance of the proposed protocol can reach 100\% in the idea circumstance. Application of the proposed protocol has also been discussed.展开更多
A dynamic modelling and controller design were presented for a single-link smart materials beam, a flexible beam bonded with piezoelectric actuators and sensors for better control performance. Taking into account boun...A dynamic modelling and controller design were presented for a single-link smart materials beam, a flexible beam bonded with piezoelectric actuators and sensors for better control performance. Taking into account bounded disturbances, a robust distributed controller was constructed based on the system model, which was described by a set of partial differential equations (PDEs) and boundary conditions (BCs) . Subsequently, a finite dimensional controller was further developed, and it was proven that this controller can stabilize the finite dimensional model with arbitrary number of flexible modes. Keywords Dynamic modelling - Robust distributed controller - Flexible beam - Smart material展开更多
A Geologic Time Scale (GTS2004) is presented that integrates currently available stratigraphic and geochronologic information. Key features of the new scale are outlined, how it was constructed, and how it can be furt...A Geologic Time Scale (GTS2004) is presented that integrates currently available stratigraphic and geochronologic information. Key features of the new scale are outlined, how it was constructed, and how it can be further improved. The accompanying International Stratigraphic Chart, issued under auspices of the International Commission on Stratigraphy (ICS), shows the current chronostratigraphic scale and ages with estimates of uncertainty for all stage boundaries. Special reference is made to the Precambrian part of the time scale, which is coming of age in terms of detail, and to the Neogene portion, which has attained an ultra-high-precision absolute-age calibration.展开更多
The solvability of a class of forward-backward stochastic differential differential equations(SDEs for short)over an arbitrarily prescribed time duration is studied. The authors design a stochastic relaxed control pro...The solvability of a class of forward-backward stochastic differential differential equations(SDEs for short)over an arbitrarily prescribed time duration is studied. The authors design a stochastic relaxed control problem, with both drift and diffusion all being controlled, so that the solvability problem is converted to a problem of finding the nodal set of the viscosity solution to a certain Hamilton-Jacobi-Bellman equation.This method overcomes the fatal difficulty encountered in the traditional contraction mapping approach to the existence theorem of such SDEs.展开更多
During the early 1800's, the current Cenozoic Era (Phillips,1840) underwent competing schemes of subdivision based on field relationships or on biological evolution.
Since opening sizable bandgaps in bilayer graphene （BLG） was proven possible, BLG has attracted considerable attention as a promising high-mobility candidate material for many electronic and optoelectronic applicati...Since opening sizable bandgaps in bilayer graphene （BLG） was proven possible, BLG has attracted considerable attention as a promising high-mobility candidate material for many electronic and optoelectronic applications. However, the bandgaps observed in the transport experiments reported in the literature are far smaller than both the theoretical predictions and the bandgaps extracted from optical measurements. In this study, we investigate the factors preventing the formation of large bandgaps and demonstrate that a -200-meV transport bandgap can be opened in BLG by scaling the gate dielectric and employing a ribbon channel to suppress the percolative transport. This is the largest transport bandgap that has been achieved in BLG to date.展开更多
Approximations using the generalized Laguerre polynomials are investigated in this paper. Error estimates for various orthogonal projections are established. These estimates generalize and improve previously published...Approximations using the generalized Laguerre polynomials are investigated in this paper. Error estimates for various orthogonal projections are established. These estimates generalize and improve previously published results on the Laguerre approximations. As an example of applications, a mixed Laguerre-Fourier spectral method for the Helmholtz equation in an exterior domain is analyzed and implemented. The proposed method enjoys optimal error estimates, and with suitable basis functions, leads to a sparse and symmetric linear system.展开更多
In this paper,an expert system for estimating capital requirement is briefly illustrated.including the essential construction of the simulation model.Then various factors which have impact on the manager's decisio...In this paper,an expert system for estimating capital requirement is briefly illustrated.including the essential construction of the simulation model.Then various factors which have impact on the manager's decision making,the datails of the program using the GURU environment,and the major roles of the human experts and the knowledge engineer are described.展开更多
Tcells are one of the most migratory cells in the body. The development and function of T cells depend on their interaction with other cells, which is, in turn, dependent on optimal cell migra- tion. T cells migrate l...Tcells are one of the most migratory cells in the body. The development and function of T cells depend on their interaction with other cells, which is, in turn, dependent on optimal cell migra- tion. T cells migrate largely in three dif- ferent ways： rapid distribution via blood vessels through hemodynamic move- ment, transendothelial migration and interstitial movement. Transendothelial migration involves sequential activation of selectins, chemokine receptors and integrin molecules expressed by migrat- ing T cells, leading to extravasation from blood vessel into local tissue environ- ments.展开更多
基金The project supported by the National Natural Science Foundation of China(59906005)the Teaching Research Award Program for Outstanding Young Teachers in High Education Institutions of MOE,China
文摘In this paper, the CE/SE method is developed to simulate the two- and three-dimensional flow-field of Pulse Detonation Engine (PDE). The conservation equations with stiff source terms for chemical reaction are solved in two steps. The detailed analysis of computational results of a PDE with a single detonation tube and a PDE with five detonation tubes are given in this paper. Complex wave systems are observed inside and outside a PDE. For a PDE with 5 detonation tubes, there is a big bow shock produced from a number of little shocks near the open ends of tubes. A lot of vortexes interact with shocks and a large expansion wave propagates forward and backward with respect to the PDE in a semi-oval shape.
文摘Vegetation or land cover maps have been made directly or indirectly available for the entire territory of China. The certainties and uncertainties of land cover statistics were analyzed by comparing three data sources: China's Vegetation Map, IGPB DISCover, and University of Maryland Product. Great similarities in the statistics of 7 aggregated land cover types were found among the three data sources, particularly between the two global land cover maps. The per pixel agreement between any 2 of 3 maps was between 38.0%—51.4%; the per pixel agreement among all three maps was only 27.1%. Certainties were found in regions where vegetation types are typical and human land use practice is relatively homogenous; the uncertainties occurred to either vegetation transition zones or regions where land cover types and land use practice are relatively diversified. Systematic and multidisciplinary efforts are necessary to promote accurate mapping of nationwide land cover types in China. Intensive efforts should be made in regions where uncertainties of land cover information are found.
文摘Natural regeneration of tree species is important to the sustainability of native forest ecosystems in the temperate zone of north- east China. This study compared the densities and heights of seedlings and the diversities of shrubs and herbs on three sites of logging op- erations: log-skidding trails (LST), logging gaps (LG) and log landing sites (LLS). Sites undisturbed by logging gaps operations were sam- pled as control. The species, counts and height of tree seedlings and the species, counts, height and percentage coverage of shrubs and herbs were recorded in the field. The highest density and greatest height of regeneration trees were observed at LG and LST. The effects of LST on the densities of broadleaved trees were greater than those of coniferous trees. The difference in seedling density between LLS and control was significant (p=0.05). There was no significant difference in average seedling height for all the tree species between the disturbed sites and control. There were more shrub and herb species at the disturbed sites than at control. The diversity of understory plants at LG was the highest among all the sites. LST and LLS were different in shrub diversity, so were LLS and control. Both LG and LLS were different from control in herb diversity. Active measures need to be taken on the operation sites to protect the coniferous trees and the diversities of under- story plants for sustaining the structure and composition of the broadleaved-Korean pine mixed forest on Changbai Mountain of China. Since different operation sites have different effects on different tree species, site-dependent actions must be taken to assure the regeneration of ecologically important tree species.
文摘The objective of this research is to identify DNA markers linked to QTLs controlling FHB resistance in wheat, and to compare if the QTLs in three resistant germplasm are common. Three wheat recombinant inbred populations derived from the crosses between Alondra (susceptible) and three resistant lines, Wangshuibai, Sumai3, and 894037, respectively, were evaluated for reaction to Fusarium graminearum in greenhouse and in field conditions over years. Simple sequence repeat (SSR) markers were screened in the populations and regression analysis was used to identify markers associated with FHB resistance. For the population of Sumai3 (resistant)/Alondra (susceptible), which contained 161 recombinant inbred lines, two SSR markers located on chromosome 3B were found to be associated with resistant QTLs. These markers accounted for 2.66.7% phenotypic variation. The 894037 (resistant)/Alondra (susceptible) population was consisted of 147 recombinant inbred lines. A total of 59 SSR primers were screened in this population and seven of them were linked to resistant QTLs. The QTLs on chromosome 3B accounted for 47.4% phenotypic variation. Minor QTLs were also located on 2D, 7A, 6B, and 4B chromosomes, and the resistant QTLs on 2D and 4B chromosomes were from Alondra. The last population of 80 recombinant inbred lines was from the cross Wangshuibai (resistant)/Alondra (susceptible). A total of 120 SSR primers were screened in this population, eight of which were linked to resistant QTLs. These markers were located on 3B, 4B, 2D, 4D, and 6D (uncertain) chromosomes respectively. The QTLs on chromosome 3B accounted for 8.927.0% phenotypic variation. The resistant QTLs on chromosomes 4B and 6D (uncertain) were from Alondra. The other QTLs were from Wangshuibai. SSR markers linked to resistant QTLs on chromosome 3B were found in all three populations, and account for higher phenotypic variation. So these markers should be useful in marker assisted selection.
基金Partial funding for this research was provided by The State Forestry Administration of China(No.2006-85)
文摘Three kinds of plant growth regulators, gibberellinA 4/7 （GA 4/7 ）, 6-benzylaminopurine （BA）, and chlormequat chloride （CCC）, were evaluated for their ability to promote strobilus and cone production in a Chinese pine （Pinus tabuliformis Carr.） clonal seed orchard. Treatments （0, 250, 500, or 1000 mg L -1 ） were applied during three periods （June- July, July-August and August-September） in 2005. Of the three plant growth regulators, GA 4/7 was the best for promoting flower and cone production. Trees sprayed with GA 4/7 （500 mg L -1 ） from June to September had significantly more female strobili and immature cones than controls and other treatments （p≤0.0001）. The best time to apply GA 4/7 was in June. BA at 500 mg L -1 significantly increased female flower and immature cone production, compared to other treatments and controls （p≤0.0001）, while promotion of male strobili was unchanged. Chlormequat chloride at 1000 mg L -1 significantly increased the number of male strobili, compared to the other treatments （p≤0.0001）. Spraying CCC at500 mg L -1 significantly increased the number of female strobili, compared to controls （p0.05）, but it had no effect on immature cone production （p0.05）. These results are important for improving seed production and seed orchard management of Chinese pine.
基金This work is supported by the Natural Science Foundation of China(60472018)the Foundation for Doctoral Degree Student Education of the Ministry Education(20020248063)the Foundation of National Laboratory for Modern Communications.
文摘A quantum key distribution scheme for quantum cryptographic network is proposed, which is implemented physically by the Greenberger-Home-Zeilinger (GHZ) triplet state. Its security is guaranteed by the correlation of the GHZ triplet state, results show this protocol is unconditionally secure. The performance of the proposed protocol can reach 100\% in the idea circumstance. Application of the proposed protocol has also been discussed.
文摘A dynamic modelling and controller design were presented for a single-link smart materials beam, a flexible beam bonded with piezoelectric actuators and sensors for better control performance. Taking into account bounded disturbances, a robust distributed controller was constructed based on the system model, which was described by a set of partial differential equations (PDEs) and boundary conditions (BCs) . Subsequently, a finite dimensional controller was further developed, and it was proven that this controller can stabilize the finite dimensional model with arbitrary number of flexible modes. Keywords Dynamic modelling - Robust distributed controller - Flexible beam - Smart material
文摘A Geologic Time Scale (GTS2004) is presented that integrates currently available stratigraphic and geochronologic information. Key features of the new scale are outlined, how it was constructed, and how it can be further improved. The accompanying International Stratigraphic Chart, issued under auspices of the International Commission on Stratigraphy (ICS), shows the current chronostratigraphic scale and ages with estimates of uncertainty for all stage boundaries. Special reference is made to the Precambrian part of the time scale, which is coming of age in terms of detail, and to the Neogene portion, which has attained an ultra-high-precision absolute-age calibration.
文摘The solvability of a class of forward-backward stochastic differential differential equations(SDEs for short)over an arbitrarily prescribed time duration is studied. The authors design a stochastic relaxed control problem, with both drift and diffusion all being controlled, so that the solvability problem is converted to a problem of finding the nodal set of the viscosity solution to a certain Hamilton-Jacobi-Bellman equation.This method overcomes the fatal difficulty encountered in the traditional contraction mapping approach to the existence theorem of such SDEs.
文摘During the early 1800's, the current Cenozoic Era (Phillips,1840) underwent competing schemes of subdivision based on field relationships or on biological evolution.
文摘Since opening sizable bandgaps in bilayer graphene （BLG） was proven possible, BLG has attracted considerable attention as a promising high-mobility candidate material for many electronic and optoelectronic applications. However, the bandgaps observed in the transport experiments reported in the literature are far smaller than both the theoretical predictions and the bandgaps extracted from optical measurements. In this study, we investigate the factors preventing the formation of large bandgaps and demonstrate that a -200-meV transport bandgap can be opened in BLG by scaling the gate dielectric and employing a ribbon channel to suppress the percolative transport. This is the largest transport bandgap that has been achieved in BLG to date.
文摘Approximations using the generalized Laguerre polynomials are investigated in this paper. Error estimates for various orthogonal projections are established. These estimates generalize and improve previously published results on the Laguerre approximations. As an example of applications, a mixed Laguerre-Fourier spectral method for the Helmholtz equation in an exterior domain is analyzed and implemented. The proposed method enjoys optimal error estimates, and with suitable basis functions, leads to a sparse and symmetric linear system.
文摘In this paper,an expert system for estimating capital requirement is briefly illustrated.including the essential construction of the simulation model.Then various factors which have impact on the manager's decision making,the datails of the program using the GURU environment,and the major roles of the human experts and the knowledge engineer are described.
文摘Tcells are one of the most migratory cells in the body. The development and function of T cells depend on their interaction with other cells, which is, in turn, dependent on optimal cell migra- tion. T cells migrate largely in three dif- ferent ways： rapid distribution via blood vessels through hemodynamic move- ment, transendothelial migration and interstitial movement. Transendothelial migration involves sequential activation of selectins, chemokine receptors and integrin molecules expressed by migrat- ing T cells, leading to extravasation from blood vessel into local tissue environ- ments.
