复方氨基酸注射液是肠外营养中氮的来源,广泛应用于不能经胃肠道给予或经胃肠道给予不能满足其营养需求的患者,在营养治疗中起重要作用。但目前对于复方氨基酸注射液临床应用的指征、剂型、剂量、时机,国内并无系统的指南或共识。为了...复方氨基酸注射液是肠外营养中氮的来源,广泛应用于不能经胃肠道给予或经胃肠道给予不能满足其营养需求的患者,在营养治疗中起重要作用。但目前对于复方氨基酸注射液临床应用的指征、剂型、剂量、时机,国内并无系统的指南或共识。为了进一步规范复方氨基酸注射液的临床应用,中华医学会肠外肠内营养学分会(Chinese Society for Parenteral and Enteral Nutrition,CSPEN)及中国抗癌协会肿瘤营养专业委员会(Chinese Society of Nutritional Oncology,CSNO)组织全国专家,在系统性文献检索的基础上,参考美国肠外肠内营养学会(American Society for Parenteral and Enteral Nutrition,ASPEN)、欧洲临床营养和代谢学会(European Society for Clinical Nutrition and Metabolism,ESPEN)、CSPEN及CSNO指南,结合我国临床实践,经多次交流讨论,达成此共识。包括10条推荐意见,涉及不同患者的蛋白质需要量及氨基酸剂型选择。展开更多
A new multi-mesh contact algorithm for three-dimensional material point method is presented. The contact algorithm faithfully recovers the opposite acting forces between colliding bodies. Collision procedures between ...A new multi-mesh contact algorithm for three-dimensional material point method is presented. The contact algorithm faithfully recovers the opposite acting forces between colliding bodies. Collision procedures between regular bodies and/or rigid bodies are treated within the same framework. Multi-value of momentum and mass are defined on every node to describe the contact/sliding/separation procedure. Both normal and tangential velocities of each particle at the contact surface are calculated in respective individual mesh. A Coulomb friction is applied to describe the sliding or slipping between the contacting bodies. The efficiency of the contact algorithm is linearly related to the number of the contacting bodies because the overlapped nodes are labeled by sweeping the material particles of all bodies when the nodal momentum and mass are formed at every time step. Numerical simulation shows that our contact algorithm possesses high accuracy and low numerical energy dissipation, which is very important for solving collision problems.展开更多
We present a highly efficient lattice Boltzmann model for simulating compressible flows. This model is based on the combination of an appropriate finite difference scheme, a 16-discrete-velocity model [Kataoka and Tsu...We present a highly efficient lattice Boltzmann model for simulating compressible flows. This model is based on the combination of an appropriate finite difference scheme, a 16-discrete-velocity model [Kataoka and Tsutahara, Phys. Rev. E 69 （2004） 035701（R）] and reasonable dispersion and dissipation terms. The dispersion term effectively reduces the oscillation at the discontinuity and enhances numerical precision. The dissipation term makes the new model more easily meet with the yon Neumann stability condition. This model works for both high-speed and low-speed flows with arbitrary specific-heat-ratio. With the new model simulation results for the well-known benchmark problems get a high accuracy compared with the analytic or experimental ones. The used benchmark tests include （i） Shock tubes such as the Sod, Lax, Sjogreen, Colella explosion wave, and collision of two strong shocks, （ii） Regular and Mach shock reflections, and （iii） Shock wave reaction on cylindrical bubble problems. With a more realistic equation of state or free-energy functional, the new model has the potential tostudy the complex procedure of shock wave reaction on porous materials.展开更多
Lattice Boltzmann （LB） modeling of high-speed compressible flows has long been attempted by various authors. One common weakness of most of previous models is the instability problem when the Mach number of the flow...Lattice Boltzmann （LB） modeling of high-speed compressible flows has long been attempted by various authors. One common weakness of most of previous models is the instability problem when the Mach number of the flow is large. In this paper we present a finite-difference LB model, which works for flows with flexible ratios of specific heats and a wide range of Mach number, from 0 to 30 or higher. Besides the discrete-velocity-model by Watari [Physica A 382 （2007） 502], a modified Lax Wendroff finite difference scheme and an artificial viscosity are introduced. The combination of the finite-difference scheme and the adding of artificial viscosity must find a balance of numerical stability versus accuracy. The proposed model is validated by recovering results of some well-known benchmark tests： shock tubes and shock reflections. The new model may be used to track shock waves and/or to study the non-equilibrium procedure in the transition between the regular and Mach reflections of shock waves, etc.展开更多
We investigate the scattering process of impulse in vertical granular chain with light impurities. When the perturbation is weak, the quantities describing the reflection rate exhibit power-law behavior with the impur...We investigate the scattering process of impulse in vertical granular chain with light impurities. When the perturbation is weak, the quantities describing the reflection rate exhibit power-law behavior with the impurity depth. The exponent is nearly independent of vi. When the perturbation is very strong, the vertical chain shows similar behavior to that of the horizontal chain, so the exponent is nearly zero. Our numerical investigation begins from the weak perturbation region and extends to the nonlinear region and found a peak of the exponent. The difficulty in extending the numerical investigation to a stronger perturbation region is analyzed.PACS numbers: 45.70.-n, 43.25.+y, 46.40.展开更多
Selecting plants adapted to the climatic and soil conditions of specific locations is essential for environmental protection and economic sustainability of agricultural and pastoral systems. This is particularly true ...Selecting plants adapted to the climatic and soil conditions of specific locations is essential for environmental protection and economic sustainability of agricultural and pastoral systems. This is particularly true for countries like China with a diversity of climates and soils and intended uses. Currently, proper species selection is difficult due to the absence of computer-based selection tools. Climate and soil GIS layers, matched with a matrix of plant characteristics through rules describing species tolerances would greatly improve the selection process. Better matching will reduce environmental hazards and economic risks associated with sub-optimal plant selection and performance. GIS-based climate and soil maps have been developed for China. A matrix of quantitative species tolerances has been developed for example forage species and used in combination with an internet map server that allows customized map creation. A web-based decision support system has been developed to provide current information and links to original data sources, supplementary materials, and selection strategies.展开更多
We generalize the Frenkel-Kontorov model to the Frenkel-Kontorova-Devonshire model in which the interaction is the triple-well potential.By use of the effective potential method,numerical solutions of eigenvalue probl...We generalize the Frenkel-Kontorov model to the Frenkel-Kontorova-Devonshire model in which the interaction is the triple-well potential.By use of the effective potential method,numerical solutions of eigenvalue problem are used to work out the exact phase diagrams of a triple-well potential W and a piecewise parabolic potential V.According to the winding numberωand the rotation numberΩ,we analyze the periodicity of the phase diagram and find some complex but regular phase structures.The properties of the phase structures are closely related to the period of the external potential.展开更多
A generalized Frenkel-Kontorova model with the Morse potentials is studied.The phase diagram reflects the nonlinear nature of the Morse potential.The correspondences of the ground states and the orbits of the area-pre...A generalized Frenkel-Kontorova model with the Morse potentials is studied.The phase diagram reflects the nonlinear nature of the Morse potential.The correspondences of the ground states and the orbits of the area-preserving map are studied numerically.Our results present a better simulation to the real systems.展开更多
文摘复方氨基酸注射液是肠外营养中氮的来源,广泛应用于不能经胃肠道给予或经胃肠道给予不能满足其营养需求的患者,在营养治疗中起重要作用。但目前对于复方氨基酸注射液临床应用的指征、剂型、剂量、时机,国内并无系统的指南或共识。为了进一步规范复方氨基酸注射液的临床应用,中华医学会肠外肠内营养学分会(Chinese Society for Parenteral and Enteral Nutrition,CSPEN)及中国抗癌协会肿瘤营养专业委员会(Chinese Society of Nutritional Oncology,CSNO)组织全国专家,在系统性文献检索的基础上,参考美国肠外肠内营养学会(American Society for Parenteral and Enteral Nutrition,ASPEN)、欧洲临床营养和代谢学会(European Society for Clinical Nutrition and Metabolism,ESPEN)、CSPEN及CSNO指南,结合我国临床实践,经多次交流讨论,达成此共识。包括10条推荐意见,涉及不同患者的蛋白质需要量及氨基酸剂型选择。
基金The project supported by the Science Foundation of Laboratory of Computational Physics,Science Foundation of China Academy of Engineering Physics,and National Natural Science Foundation of China under Grant Nos.10702010,10775018,10472052,and 10604010
文摘A new multi-mesh contact algorithm for three-dimensional material point method is presented. The contact algorithm faithfully recovers the opposite acting forces between colliding bodies. Collision procedures between regular bodies and/or rigid bodies are treated within the same framework. Multi-value of momentum and mass are defined on every node to describe the contact/sliding/separation procedure. Both normal and tangential velocities of each particle at the contact surface are calculated in respective individual mesh. A Coulomb friction is applied to describe the sliding or slipping between the contacting bodies. The efficiency of the contact algorithm is linearly related to the number of the contacting bodies because the overlapped nodes are labeled by sweeping the material particles of all bodies when the nodal momentum and mass are formed at every time step. Numerical simulation shows that our contact algorithm possesses high accuracy and low numerical energy dissipation, which is very important for solving collision problems.
基金Supported by the Science Foundations of LCP and CAEP under Grant Nos.2009A0102005 and 2009B0101012the National Basic Research Program (973 Program) under Grant No.2007CB815105the National Natural Science Foundation under Grant Nos.10775018,10702010,and 10775088
文摘We present a highly efficient lattice Boltzmann model for simulating compressible flows. This model is based on the combination of an appropriate finite difference scheme, a 16-discrete-velocity model [Kataoka and Tsutahara, Phys. Rev. E 69 （2004） 035701（R）] and reasonable dispersion and dissipation terms. The dispersion term effectively reduces the oscillation at the discontinuity and enhances numerical precision. The dissipation term makes the new model more easily meet with the yon Neumann stability condition. This model works for both high-speed and low-speed flows with arbitrary specific-heat-ratio. With the new model simulation results for the well-known benchmark problems get a high accuracy compared with the analytic or experimental ones. The used benchmark tests include （i） Shock tubes such as the Sod, Lax, Sjogreen, Colella explosion wave, and collision of two strong shocks, （ii） Regular and Mach shock reflections, and （iii） Shock wave reaction on cylindrical bubble problems. With a more realistic equation of state or free-energy functional, the new model has the potential tostudy the complex procedure of shock wave reaction on porous materials.
基金the Science Foundation of Laboratory of Computational Physics,the State Key Basic Research Program (973 Program) under Grant No.2007CB815105National Natural Science Foundation of China under Grant Nos.10775018,10474137,10702010,and 10604010
文摘Lattice Boltzmann （LB） modeling of high-speed compressible flows has long been attempted by various authors. One common weakness of most of previous models is the instability problem when the Mach number of the flow is large. In this paper we present a finite-difference LB model, which works for flows with flexible ratios of specific heats and a wide range of Mach number, from 0 to 30 or higher. Besides the discrete-velocity-model by Watari [Physica A 382 （2007） 502], a modified Lax Wendroff finite difference scheme and an artificial viscosity are introduced. The combination of the finite-difference scheme and the adding of artificial viscosity must find a balance of numerical stability versus accuracy. The proposed model is validated by recovering results of some well-known benchmark tests： shock tubes and shock reflections. The new model may be used to track shock waves and/or to study the non-equilibrium procedure in the transition between the regular and Mach reflections of shock waves, etc.
文摘We investigate the scattering process of impulse in vertical granular chain with light impurities. When the perturbation is weak, the quantities describing the reflection rate exhibit power-law behavior with the impurity depth. The exponent is nearly independent of vi. When the perturbation is very strong, the vertical chain shows similar behavior to that of the horizontal chain, so the exponent is nearly zero. Our numerical investigation begins from the weak perturbation region and extends to the nonlinear region and found a peak of the exponent. The difficulty in extending the numerical investigation to a stronger perturbation region is analyzed.PACS numbers: 45.70.-n, 43.25.+y, 46.40.
文摘Selecting plants adapted to the climatic and soil conditions of specific locations is essential for environmental protection and economic sustainability of agricultural and pastoral systems. This is particularly true for countries like China with a diversity of climates and soils and intended uses. Currently, proper species selection is difficult due to the absence of computer-based selection tools. Climate and soil GIS layers, matched with a matrix of plant characteristics through rules describing species tolerances would greatly improve the selection process. Better matching will reduce environmental hazards and economic risks associated with sub-optimal plant selection and performance. GIS-based climate and soil maps have been developed for China. A matrix of quantitative species tolerances has been developed for example forage species and used in combination with an internet map server that allows customized map creation. A web-based decision support system has been developed to provide current information and links to original data sources, supplementary materials, and selection strategies.
基金Supported by the National Natural Science Foundation of China under Grant No.19774049Science Foundation of China Academy of Engineering Physics under Grant No.980112.
文摘We generalize the Frenkel-Kontorov model to the Frenkel-Kontorova-Devonshire model in which the interaction is the triple-well potential.By use of the effective potential method,numerical solutions of eigenvalue problem are used to work out the exact phase diagrams of a triple-well potential W and a piecewise parabolic potential V.According to the winding numberωand the rotation numberΩ,we analyze the periodicity of the phase diagram and find some complex but regular phase structures.The properties of the phase structures are closely related to the period of the external potential.
基金Supported by the National Natural Science Foundation of China under Grant No.1945004Science Foundation of China Academy of Engineering Physics under Grant No.970116.
文摘A generalized Frenkel-Kontorova model with the Morse potentials is studied.The phase diagram reflects the nonlinear nature of the Morse potential.The correspondences of the ground states and the orbits of the area-preserving map are studied numerically.Our results present a better simulation to the real systems.
