The aim of this paper is to show that every local 2-cocycle of a von Neumann algebra R with coefficients in S (a unital dual R-bimodule) is a 2-cocycle.
In this paper,we prove that every generalized Jordan derivation associate with a Hochschild 2-cocycle from the algebra of upper triangular matrices to its bimodule is the sum of a generalized derivation and an antider...In this paper,we prove that every generalized Jordan derivation associate with a Hochschild 2-cocycle from the algebra of upper triangular matrices to its bimodule is the sum of a generalized derivation and an antiderivation.展开更多
This article presents a new method for G2 continuous interpolation of an arbitrary sequence of points on an implicit or parametric surfaee with prescribed tangent direction and curvature vector, respectively, at every...This article presents a new method for G2 continuous interpolation of an arbitrary sequence of points on an implicit or parametric surfaee with prescribed tangent direction and curvature vector, respectively, at every point. First, a G2 continuous curve is constructed in three-dimensional space. Then the curve is projected normally onto the given surface. The desired interpolation curve is just the projection curve, which can be obtained by numerieally solving the initialvalue problems for a system of first-order ordinary differential equations in the parametric domain for parametric case or in three-dimensional space for implicit ease. Several shape parameters are introduced into the resulting curve, which can be used in subsequent interactive modification so that the shape of the resulting curve meets our demand. The presented method is independent of the geometry and parameterization of the base surface. Numerical experiments demonstrate that it is effective and potentially useful in numerical control （NC） machining, path planning for robotic fibre placement, patterns design on surface and other industrial and research fields.展开更多
A large body of literature suggests that bone metabolism is susceptible to the ill effects of reactive species that accumulate in the body and cause cellular dysfunction. One of the body＇s front lines in defense agai...A large body of literature suggests that bone metabolism is susceptible to the ill effects of reactive species that accumulate in the body and cause cellular dysfunction. One of the body＇s front lines in defense against such damage is the transcription factor, Nrf2. This transcription factor regulates a plethora of antioxidant and cellular defense pathways to protect cells from such damage. Despite the breadth of knowledge of both the function of Nrf2 and the effects of reactive species in bone metabolism, the direct role of Nrf2 in skeletal biology has yet to be thoroughly examined. Thus, in the current study, we have examined the role of Nrf2 in postnatal bone metabolism in mice. Mice lacking Nrf2 （Nrf2-/-） exhibited a marked deficit in postnatal bone acquisition, which was most severe at 3 weeks of age when osteoblast numbers were 12-fold less than observed in control animals. While primary osteoblasts from Nrf2-/- mice functioned normally in vitro, the colony forming capacity of bone marrow stromal cells （BMSCs） from these mice was significantly reduced compared to controls. This defect could be rescued through treatment with the radical scavenger N-acetyl cysteine （NAC）, suggesting that increased reactive species stress might impair early osteoblastogenesis in BMSCs and lead to the failure of bone acquisition observed in Nrf2-/- animals. Taken together, these studies suggest Nrf2 represents a key pathway in regulating bone metabolism, which may provide future therapeutic targets to treat osteoporosis.展开更多
As an important part of the mass balance of the Ice Sheet,Supra-glacial Water not only reflects the diversity of polar environmental changes,but also plays an important role in the study of global climate and environm...As an important part of the mass balance of the Ice Sheet,Supra-glacial Water not only reflects the diversity of polar environmental changes,but also plays an important role in the study of global climate and environmental changes.In this paper,we chose northern Greenland as the research area,and constructed a Normalized Enhanced Water Index(NEWI)based on the high-precision WorldView-2 images of different phases during the ablation period in northern Greenland,followed by a statistical analysis on the spectral characteristics of the images were for the typical features in the study area.Then the fuzzy areas with similar gray values of thin sea ice and shallow ice water bodies were located,according to the distribution rules of ground objects and histogram graphic features of the images,so as to enhance the contrast of ground objects between the regions,and finally the extraction of the fine range of water bodies on the ice surface.Experimental results showed that the proposed index effectively highlighted the ice water with the water of the reflectivity difference,compared with the commonly used water index NDWI,etc.,especially in shallow water,which contributes to differentiation from other objects.The precision evaluation showed that the applied method of extraction has higher degree of refinement compared with other methods,by which the ice water can get complete ice water effectively.展开更多
In this paper, we study the gravitational quasi-normal modes（QNMs） for a static R^2 black hole（BH） in Anti-de Sitter（AdS） spacetime. The corresponding master equation of odd parity is derived and the QNMs are ev...In this paper, we study the gravitational quasi-normal modes（QNMs） for a static R^2 black hole（BH） in Anti-de Sitter（AdS） spacetime. The corresponding master equation of odd parity is derived and the QNMs are evaluated by the Horowitz and Hubeny method. Meanwhile the stability of such BH is also discussed through the temporal evolution of the perturbation field. Here we mainly consider the coefficient λ, which is related to the radius of AdS black hole, on the QNMs of the R^2 AdS BH. The results show that the Re（ω） and ｜Im（ω）｜ of the QNMs increase together as ｜λ｜ increases for a given angular momentum number l. That indicates with a larger value of ｜λ｜ the corresponding R^2 AdS BH returns to stable much more quickly. The dynamic evolution of the perturbation field is consistent with the results derived by the Horowitz and Hubeny method. Since in the conformal field theory the QNMs can reflect its approach to equilibrium, so our related results could be referential to studies of the AdS/CFT conjecture. The relationship between λ and the properties of the static R^2 BH might be helpful for the development of R^2 gravitational theory.展开更多
The FY-2C meteorological satellite had been working well for 8 years as of October 19, 2012. Though the satellite was originally designed to work for 3 years, it still operates steadily. As the nation's first oper...The FY-2C meteorological satellite had been working well for 8 years as of October 19, 2012. Though the satellite was originally designed to work for 3 years, it still operates steadily. As the nation's first operational first-generation geo- stationary meteorological satellite, FY-2C works together with the following satellites FY-2D, FY-2E and FY-2F, in a operational mode of two operational plus two backup ones. FY-2C, FY-2D and FY-2E were the second batch satellites of FY-2 series展开更多
LiNi1-xCoxO2 cathode materials for lithium ion batteries were synthesized by the co-precipitation and solid-state reaction methods with LiOH·H2O, Ni(NO3)2·6H2O and Co(NO3)2·6H2O as raw materials. The ma...LiNi1-xCoxO2 cathode materials for lithium ion batteries were synthesized by the co-precipitation and solid-state reaction methods with LiOH·H2O, Ni(NO3)2·6H2O and Co(NO3)2·6H2O as raw materials. The materials were characterized by XRD, SEM and electrochemical tests. The results showed that synthesized cathode materials were with layered structure similar to α-NaFeO2 and uniform morphology and nearly normal grain size distribution and better electrochemical performance when x was 0.18. The first charge and discharge capacity of the cathode material was 224.3 mAh·g-1 and 194.2 mAh·g-1, respectively. 88.5% of the first discharge capacity remained at the 20th cycle.展开更多
基金the National Natural Science Foundation of China(1 0 0 71 0 4 7)
文摘The aim of this paper is to show that every local 2-cocycle of a von Neumann algebra R with coefficients in S (a unital dual R-bimodule) is a 2-cocycle.
基金Supported by the National Natural Science Foundation of China (Grant No. A010602)
文摘In this paper,we prove that every generalized Jordan derivation associate with a Hochschild 2-cocycle from the algebra of upper triangular matrices to its bimodule is the sum of a generalized derivation and an antiderivation.
基金National Natural Science Foundation of China(60673026,50875130,50805075 and 50875126)
文摘This article presents a new method for G2 continuous interpolation of an arbitrary sequence of points on an implicit or parametric surfaee with prescribed tangent direction and curvature vector, respectively, at every point. First, a G2 continuous curve is constructed in three-dimensional space. Then the curve is projected normally onto the given surface. The desired interpolation curve is just the projection curve, which can be obtained by numerieally solving the initialvalue problems for a system of first-order ordinary differential equations in the parametric domain for parametric case or in three-dimensional space for implicit ease. Several shape parameters are introduced into the resulting curve, which can be used in subsequent interactive modification so that the shape of the resulting curve meets our demand. The presented method is independent of the geometry and parameterization of the base surface. Numerical experiments demonstrate that it is effective and potentially useful in numerical control （NC） machining, path planning for robotic fibre placement, patterns design on surface and other industrial and research fields.
基金supported by a Johns Hopkins Musculoskeletal Research Pilot and Feasibility Grant (RKT) and NIH R01 AR062074 (DJD)
文摘A large body of literature suggests that bone metabolism is susceptible to the ill effects of reactive species that accumulate in the body and cause cellular dysfunction. One of the body＇s front lines in defense against such damage is the transcription factor, Nrf2. This transcription factor regulates a plethora of antioxidant and cellular defense pathways to protect cells from such damage. Despite the breadth of knowledge of both the function of Nrf2 and the effects of reactive species in bone metabolism, the direct role of Nrf2 in skeletal biology has yet to be thoroughly examined. Thus, in the current study, we have examined the role of Nrf2 in postnatal bone metabolism in mice. Mice lacking Nrf2 （Nrf2-/-） exhibited a marked deficit in postnatal bone acquisition, which was most severe at 3 weeks of age when osteoblast numbers were 12-fold less than observed in control animals. While primary osteoblasts from Nrf2-/- mice functioned normally in vitro, the colony forming capacity of bone marrow stromal cells （BMSCs） from these mice was significantly reduced compared to controls. This defect could be rescued through treatment with the radical scavenger N-acetyl cysteine （NAC）, suggesting that increased reactive species stress might impair early osteoblastogenesis in BMSCs and lead to the failure of bone acquisition observed in Nrf2-/- animals. Taken together, these studies suggest Nrf2 represents a key pathway in regulating bone metabolism, which may provide future therapeutic targets to treat osteoporosis.
基金supported by the 2020 Key project of Science and Technology for Economy(Grant No. SQ2020YFF0426316)。
文摘As an important part of the mass balance of the Ice Sheet,Supra-glacial Water not only reflects the diversity of polar environmental changes,but also plays an important role in the study of global climate and environmental changes.In this paper,we chose northern Greenland as the research area,and constructed a Normalized Enhanced Water Index(NEWI)based on the high-precision WorldView-2 images of different phases during the ablation period in northern Greenland,followed by a statistical analysis on the spectral characteristics of the images were for the typical features in the study area.Then the fuzzy areas with similar gray values of thin sea ice and shallow ice water bodies were located,according to the distribution rules of ground objects and histogram graphic features of the images,so as to enhance the contrast of ground objects between the regions,and finally the extraction of the fine range of water bodies on the ice surface.Experimental results showed that the proposed index effectively highlighted the ice water with the water of the reflectivity difference,compared with the commonly used water index NDWI,etc.,especially in shallow water,which contributes to differentiation from other objects.The precision evaluation showed that the applied method of extraction has higher degree of refinement compared with other methods,by which the ice water can get complete ice water effectively.
基金supported by the National Natural Science Foundation of China(Grant Nos.11205254,11178018,11375279,and 11605015)the Fundamental Research Funds for the Central Universities,China(Grant Nos.106112016CDJXY300002 and CDJRC10300003)+1 种基金the Chinese State Scholarship Fund,FAPESP(Grant No.2012/08934-0)the Natural Science Foundation Project of CQ CSTC(Grant No.2011BB0052)
文摘In this paper, we study the gravitational quasi-normal modes（QNMs） for a static R^2 black hole（BH） in Anti-de Sitter（AdS） spacetime. The corresponding master equation of odd parity is derived and the QNMs are evaluated by the Horowitz and Hubeny method. Meanwhile the stability of such BH is also discussed through the temporal evolution of the perturbation field. Here we mainly consider the coefficient λ, which is related to the radius of AdS black hole, on the QNMs of the R^2 AdS BH. The results show that the Re（ω） and ｜Im（ω）｜ of the QNMs increase together as ｜λ｜ increases for a given angular momentum number l. That indicates with a larger value of ｜λ｜ the corresponding R^2 AdS BH returns to stable much more quickly. The dynamic evolution of the perturbation field is consistent with the results derived by the Horowitz and Hubeny method. Since in the conformal field theory the QNMs can reflect its approach to equilibrium, so our related results could be referential to studies of the AdS/CFT conjecture. The relationship between λ and the properties of the static R^2 BH might be helpful for the development of R^2 gravitational theory.
文摘The FY-2C meteorological satellite had been working well for 8 years as of October 19, 2012. Though the satellite was originally designed to work for 3 years, it still operates steadily. As the nation's first operational first-generation geo- stationary meteorological satellite, FY-2C works together with the following satellites FY-2D, FY-2E and FY-2F, in a operational mode of two operational plus two backup ones. FY-2C, FY-2D and FY-2E were the second batch satellites of FY-2 series
文摘LiNi1-xCoxO2 cathode materials for lithium ion batteries were synthesized by the co-precipitation and solid-state reaction methods with LiOH·H2O, Ni(NO3)2·6H2O and Co(NO3)2·6H2O as raw materials. The materials were characterized by XRD, SEM and electrochemical tests. The results showed that synthesized cathode materials were with layered structure similar to α-NaFeO2 and uniform morphology and nearly normal grain size distribution and better electrochemical performance when x was 0.18. The first charge and discharge capacity of the cathode material was 224.3 mAh·g-1 and 194.2 mAh·g-1, respectively. 88.5% of the first discharge capacity remained at the 20th cycle.
