There is a phase transition between quasi-periodic state and intermittent chaos in GOY model with a critical value δ0. When we add a modulated periodic externa/force to the system, the phase transition can also be fo...There is a phase transition between quasi-periodic state and intermittent chaos in GOY model with a critical value δ0. When we add a modulated periodic externa/force to the system, the phase transition can also be found with a critical value δe. Due to coupling between the force and the intrinsic fluctuation of the velocity on shells in GOY model, the stability of the system has been changed, which results in the variation of the critical value. For proper intensity and period of the force, δe is unequal to δ0. The critical value is a nonlinear function of amplitude of the force, and the fluctuation of the velocity can resonate with the external force for certain period Te.展开更多
In this paper, a V-cycle multigrid method is presented for a Hermite rectangular element. By defining proper mesh-dependent inner product and transfer operator, we obtain its convergence property and the uniform conve...In this paper, a V-cycle multigrid method is presented for a Hermite rectangular element. By defining proper mesh-dependent inner product and transfer operator, we obtain its convergence property and the uniform convergence rate independent of mesh size and level are established.展开更多
A nonlinear lateral-torsional coupled vibration model of a planetary gear system was established by taking transmission errors,time varying meshing stiffness and multiple gear backlashes into account.The bifurcation d...A nonlinear lateral-torsional coupled vibration model of a planetary gear system was established by taking transmission errors,time varying meshing stiffness and multiple gear backlashes into account.The bifurcation diagram of the system's motion state with rotational speed of sun gear was conducted through four steps.As a bifurcation parameter,the effect of rotational speed on the bifurcation properties of the system was assessed.The study results reveal that periodic motion is the main motion state of planetary gear train in low speed region when ns<2 350 r/min,but chaos motion state is dominant in high speed region when ns>2 350 r/min,The way of periodic motion to chaos is doubling bifurcation.There are two kinds of unstable modes and nine unstable regions in the speed region when 1 000 r/min<ns<3 000 r/min.展开更多
Objective To analyze the characteristics of hepatic metastasis of pure immature ovarian teratoma and explore its proper diagnosis and treatment.Methods Eighteen cases of hepatic metastasis of pure immature ovarian ter...Objective To analyze the characteristics of hepatic metastasis of pure immature ovarian teratoma and explore its proper diagnosis and treatment.Methods Eighteen cases of hepatic metastasis of pure immature ovarian teratoma were included in this study. The clinical stage, operation, chemotherapy and histopathology of primary and secondary tumors as well as the data from long term follow-ups were analyzed retrospectively,Results All of the hepatic metastatic tumors were located on the surface of the liver. 61.1% (11/18) of them were clinical stage Ⅲ and 44.4% (8/18) were grade 1 at first operation. The hepatic metastatic rate was 16.7% (3/18) in the standard adjuvant chemotherapy group but increased markedly to 31.2% (15/48) in the irregular chemotherapy group. Auxiliary diagnostic methods could not indicate the correct results. The surgical resection rate of hepatic metastasis of pure immature ovarian teratoma was 94.4% (17/18). There were less complications in the group with tumor diameter less than 15 cm. The follow-up time ranged from 3 to 205 months with a mean of 20.9 months. The 3-year-survival rate was 77.8% (14/ 18), and mortality rate was 22.2%. The 5- and 10-year-survival rate was 55.6% (10/18) and 38.9% (7/18), respectively. The rate of loss in follow-up was 22.2% (4/18) and 38.9% (7/18), respectively, and one patient has survived for more than 17 years.Conclusions The hepatic metastatic rate of pure immature ovarian teratoma could be decreased using standard adjuvant chemotherapy. Suitable surgical treatment could reduce complications and improve the prognosis for patients.展开更多
In this paper, we study the weak type heterodimensional cycle with orbit-flip in its non-transversal orbit by using the local moving frame approach. For the first two subcases, we present the sufficient conditions for...In this paper, we study the weak type heterodimensional cycle with orbit-flip in its non-transversal orbit by using the local moving frame approach. For the first two subcases, we present the sufficient conditions for the existence, uniqueness and non-coexistence of the homoclinic orbit, heteroclinic orbit and periodic orbit. Based on the bifurcation analysis, the bifurcation surfaces and the existence regions are located. And for the third subcase, we theoretically established both the coexistence condition for the homoclinic loop and the periodic orbit and the coexistence condition for the persistent heterodimensional cycle and multiple periodic orbits due to the weak type of the transversal heteroclinic orbit. Moreover, an analytical example is presented for this subcase.展开更多
The Tibetan Plateau(TP)and Arctic permafrost constitute two large reservoirs of organic carbon,but processes which control carbon accumulation within the surface soil layer of these areas would differ due to the inter...The Tibetan Plateau(TP)and Arctic permafrost constitute two large reservoirs of organic carbon,but processes which control carbon accumulation within the surface soil layer of these areas would differ due to the interplay of climate,soil and vegetation type.Here,we synthesized currently available soil carbon data to show that mean organic carbon density in the topsoil(0-10 cm)in TP grassland(3.12±0.52 kg C m^(-2))is less than half of that in Arctic tundra(6.70±1.94 kg C m^(-2)).Such difference is primarily attributed to their difference in radiocarbon-inferred soil carbon turnover times(547 years for TP grassland versus 1609 years for Arctic tundra)rather than to their marginal difference in topsoil carbon inputs.Our findings highlight the importance of improving regional-specific soil carbon turnover and its controlling mechanisms across permafrost affected zones in ecosystem models to fully represent carbon-climate feedback.展开更多
Most of life maintains itself through turnover, namely cell proliferation, movement and elimination. Hydra's cells, for example, disappear continuously from the ends of tenta- cles, but these cells are replenished by...Most of life maintains itself through turnover, namely cell proliferation, movement and elimination. Hydra's cells, for example, disappear continuously from the ends of tenta- cles, but these cells are replenished by cell proliferation within the body. Inspired by such a biological fact, and together with various operations of polynomials, I here propose polynomial-life model toward analysis of some phenomena in multicellular organisms. Polynomial life consists of multicells that are expressed as multivariable polynomials. A cell is expressed as a term of polynomial, in which point (m, n) is described as a term zmy~ and the condition is described as its coefficient. Starting with a single term and following reductions by set of polynomials, I simulate the development from a cell to a multicell. In order to confirm uniqueness of the eventual multicell-pattern, GrSbner base can be used, which has been conventionally used to ensure uniqueness of normal form in the mathematical context. In this framework, I present various patterns through the polynomial-life model and discuss patterns maintained through turnover. Cell elimina- tion seems to play an important role in turnover, which may shed some light on cancer or regenerative medicine.展开更多
基金the Major Program of National Natural Science Foundation of China under Grant No.10335010National Natural Science Foundation-the Science Foundation of China Academy of Engineering Physics (NSAF) under Grant No.10576005
文摘There is a phase transition between quasi-periodic state and intermittent chaos in GOY model with a critical value δ0. When we add a modulated periodic externa/force to the system, the phase transition can also be found with a critical value δe. Due to coupling between the force and the intrinsic fluctuation of the velocity on shells in GOY model, the stability of the system has been changed, which results in the variation of the critical value. For proper intensity and period of the force, δe is unequal to δ0. The critical value is a nonlinear function of amplitude of the force, and the fluctuation of the velocity can resonate with the external force for certain period Te.
基金Supported by NSF of China(10971203)Supported by the NSF of the education Department of Henan Province (2009A110017)
文摘In this paper, a V-cycle multigrid method is presented for a Hermite rectangular element. By defining proper mesh-dependent inner product and transfer operator, we obtain its convergence property and the uniform convergence rate independent of mesh size and level are established.
基金Project(50775108) supported by the National Natural Science Foundation of China
文摘A nonlinear lateral-torsional coupled vibration model of a planetary gear system was established by taking transmission errors,time varying meshing stiffness and multiple gear backlashes into account.The bifurcation diagram of the system's motion state with rotational speed of sun gear was conducted through four steps.As a bifurcation parameter,the effect of rotational speed on the bifurcation properties of the system was assessed.The study results reveal that periodic motion is the main motion state of planetary gear train in low speed region when ns<2 350 r/min,but chaos motion state is dominant in high speed region when ns>2 350 r/min,The way of periodic motion to chaos is doubling bifurcation.There are two kinds of unstable modes and nine unstable regions in the speed region when 1 000 r/min<ns<3 000 r/min.
文摘Objective To analyze the characteristics of hepatic metastasis of pure immature ovarian teratoma and explore its proper diagnosis and treatment.Methods Eighteen cases of hepatic metastasis of pure immature ovarian teratoma were included in this study. The clinical stage, operation, chemotherapy and histopathology of primary and secondary tumors as well as the data from long term follow-ups were analyzed retrospectively,Results All of the hepatic metastatic tumors were located on the surface of the liver. 61.1% (11/18) of them were clinical stage Ⅲ and 44.4% (8/18) were grade 1 at first operation. The hepatic metastatic rate was 16.7% (3/18) in the standard adjuvant chemotherapy group but increased markedly to 31.2% (15/48) in the irregular chemotherapy group. Auxiliary diagnostic methods could not indicate the correct results. The surgical resection rate of hepatic metastasis of pure immature ovarian teratoma was 94.4% (17/18). There were less complications in the group with tumor diameter less than 15 cm. The follow-up time ranged from 3 to 205 months with a mean of 20.9 months. The 3-year-survival rate was 77.8% (14/ 18), and mortality rate was 22.2%. The 5- and 10-year-survival rate was 55.6% (10/18) and 38.9% (7/18), respectively. The rate of loss in follow-up was 22.2% (4/18) and 38.9% (7/18), respectively, and one patient has survived for more than 17 years.Conclusions The hepatic metastatic rate of pure immature ovarian teratoma could be decreased using standard adjuvant chemotherapy. Suitable surgical treatment could reduce complications and improve the prognosis for patients.
基金supported by the Foundation of Zhejiang Sci-Tech University (ZSTU)(Grant No. 11432732611046)National Natural Science Foundation of China (Grant No. 10671069)
文摘In this paper, we study the weak type heterodimensional cycle with orbit-flip in its non-transversal orbit by using the local moving frame approach. For the first two subcases, we present the sufficient conditions for the existence, uniqueness and non-coexistence of the homoclinic orbit, heteroclinic orbit and periodic orbit. Based on the bifurcation analysis, the bifurcation surfaces and the existence regions are located. And for the third subcase, we theoretically established both the coexistence condition for the homoclinic loop and the periodic orbit and the coexistence condition for the persistent heterodimensional cycle and multiple periodic orbits due to the weak type of the transversal heteroclinic orbit. Moreover, an analytical example is presented for this subcase.
基金This work was supported by Preliminary Research on Three Poles Environment and Climate Change(2019YFC1509103)the National Natural Science Foundation of China(41861134036 and 41922004)+1 种基金the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0606)the Strategic Priority Research Program(A)of the Chinese Academy of Sciences(XDA19070303 and XDA20050101).
文摘The Tibetan Plateau(TP)and Arctic permafrost constitute two large reservoirs of organic carbon,but processes which control carbon accumulation within the surface soil layer of these areas would differ due to the interplay of climate,soil and vegetation type.Here,we synthesized currently available soil carbon data to show that mean organic carbon density in the topsoil(0-10 cm)in TP grassland(3.12±0.52 kg C m^(-2))is less than half of that in Arctic tundra(6.70±1.94 kg C m^(-2)).Such difference is primarily attributed to their difference in radiocarbon-inferred soil carbon turnover times(547 years for TP grassland versus 1609 years for Arctic tundra)rather than to their marginal difference in topsoil carbon inputs.Our findings highlight the importance of improving regional-specific soil carbon turnover and its controlling mechanisms across permafrost affected zones in ecosystem models to fully represent carbon-climate feedback.
文摘Most of life maintains itself through turnover, namely cell proliferation, movement and elimination. Hydra's cells, for example, disappear continuously from the ends of tenta- cles, but these cells are replenished by cell proliferation within the body. Inspired by such a biological fact, and together with various operations of polynomials, I here propose polynomial-life model toward analysis of some phenomena in multicellular organisms. Polynomial life consists of multicells that are expressed as multivariable polynomials. A cell is expressed as a term of polynomial, in which point (m, n) is described as a term zmy~ and the condition is described as its coefficient. Starting with a single term and following reductions by set of polynomials, I simulate the development from a cell to a multicell. In order to confirm uniqueness of the eventual multicell-pattern, GrSbner base can be used, which has been conventionally used to ensure uniqueness of normal form in the mathematical context. In this framework, I present various patterns through the polynomial-life model and discuss patterns maintained through turnover. Cell elimina- tion seems to play an important role in turnover, which may shed some light on cancer or regenerative medicine.