目的验证基于临床CT的数字体相关(digital volume correlation,DVC)方法在测量股骨内部变形场时的准确性,并通过DVC进一步测量股骨在跌倒情况下的内部变形,验证基于临床CT的有限元分析方法(finite element analysis,FEA)在计算股骨内部...目的验证基于临床CT的数字体相关(digital volume correlation,DVC)方法在测量股骨内部变形场时的准确性,并通过DVC进一步测量股骨在跌倒情况下的内部变形,验证基于临床CT的有限元分析方法(finite element analysis,FEA)在计算股骨内部变形场的准确性。方法使用猪股骨,模拟侧向跌倒姿态,进行分步力学加载实验,同步进行多次CT成像。通过重复扫描和虚拟位移验证DVC方法的准确性。DVC以子体积作为配准两组图像的研究对象,分别设置8、12、16和20 mm的子体积进行测试。量化误差指标包括位移系统误差-平均值(mean)、位移随机误差-标准差(standard deviation,SD)、应变准确度-平均绝对误差(mean absolute error,MAER)和应变精确度-标准差误差(standard deviation of the error,SDER)。基于CT图像建立股骨有限元模型,模拟实验条件,计算股骨内部位移,与DVC测量的内部变形场对比验证。结果基于临床CT的DVC方法重复扫描位移偏差小于0.013 mm,MAER和SDER均小于200με;虚拟位移偏差小于0.098 mm,MAER为1093~1687με,SDER为604~1267με,远小于骨组织屈服应变。FEA计算的位移和DVC测量的位移之间具有较强的相关性(R^(2)≥0.76,P<0.05)。结论基于临床CT的DVC方法可以准确测量股骨内部变形场,并且基于临床CT的有限元模型可以准确计算股骨内部变形场。展开更多
The transfer ionization of atom by ion impact offers a very suitable test ground of quantum many-body problem[1],because the final state involves three particles (the projectile, the emitted electron and the recoil io...The transfer ionization of atom by ion impact offers a very suitable test ground of quantum many-body problem[1],because the final state involves three particles (the projectile, the emitted electron and the recoil ion). The experimentaltechniques are available to perform kinematically complete measurements on these processes now.The experiment was performed using a reaction microscope at the Institute of Modern Physics, CAS[2]. Thedata was analyzed in terms of Dalitz spectrum which is presented in Fig. 1. In this figure, the Dalitz plot is展开更多
The reaction microscope (COLTRIMS as well) is a novel technique for the investigation of the dynamics ofion-atoms collisions. Exploiting this technique, a large variety of kinematically complete experiments on electro...The reaction microscope (COLTRIMS as well) is a novel technique for the investigation of the dynamics ofion-atoms collisions. Exploiting this technique, a large variety of kinematically complete experiments on electrontransfer and ionization have been performed. However, the understanding of these experimental results is farfrom satisfactory, especially for collision energy in the intermediate-energy range. The classical-trajectory MonteCarlo method (CTMC) proposed by Abrines and Percival[1] shed some light on the problem. This method has ademonstrated region of applicability in the intermediate-energy range.展开更多
Electron induced ionization-excitation (IE) of helium is a basic four-body Coulomb problem in which all thefour charged particles are actively involved. It is much more challenging to both experiment and theory in con...Electron induced ionization-excitation (IE) of helium is a basic four-body Coulomb problem in which all thefour charged particles are actively involved. It is much more challenging to both experiment and theory in contrastto direct ionization with the residual He+ ion in the ground state. The 2s or 2p separated TDCS data, especially atlow incident energy range where the high order effects are expected to play a significant role, would offer the moststringent test to theoretical models. However, only one experiment at high incident energy achieved the TDCSs for2p state till now due to the small cross section and the low detection efficiency for multi-coincidence events[1].展开更多
The momentum projecting techniques have been well applied so as to explore the mechanisms of electronemissions as well as the dynamical effects which influenced the momentum distribution of the electrons ionized inion...The momentum projecting techniques have been well applied so as to explore the mechanisms of electronemissions as well as the dynamical effects which influenced the momentum distribution of the electrons ionized inion-atom collisions[1??3]. Usually, the emitted electrons will be projected onto the scattering plane, which was definedas the plane containing the initial and the final momentum vectors of the projectile, considering the conservationlaws and rotational symmetry around the beam axis. It is well known that the ejected electrons will be influencedsimultaneously by a combined coulomb potential from the recoil ions and the projectile ions. Qualitatively, this展开更多
The cooling of heavy ions can provide high-quality beams that are especially important for high-precisionexperimental nuclear and atomic physics. The laser cooling of relativistic C3+ ion beams at the experimental coo...The cooling of heavy ions can provide high-quality beams that are especially important for high-precisionexperimental nuclear and atomic physics. The laser cooling of relativistic C3+ ion beams at the experimental coolerstorage ring (CSRe) is being currently prepared at Institute of Modern Physics (IMP) in Lanzhou. An electroncyclotron resonance ion source (ECRIS) will be used to produce C3+ ion beams. Meanwhile, O4+ ions could alsobe produced due to residual gas because of the same mass-to-charge ratio. Therefore, both C3+ and O4+ ion beamswill be injected and circulate in a storage ring during the laser cooling experiment at the same time. A higher ratioof C3+ ions will lead to a better result for the laser cooling experiment.展开更多
We have investigated the single capture with simultaneous single ionization in He2+ collisions with argon bymeans of reaction microscopes[1]. Here, we report the dependence of the azimuth angle (φe) of the relatively...We have investigated the single capture with simultaneous single ionization in He2+ collisions with argon bymeans of reaction microscopes[1]. Here, we report the dependence of the azimuth angle (φe) of the relatively high-energy electrons (kinetic energy > 20 eV) on the transversal recoil momentum (pr⊥) in single capture with doubleionization process for 30 keV/u He2+ collisions with Ar. It is noted that the relatively high-energy electrons mainlyresult from binary encounter (BE) between the target electrons and the projectiles for the present reaction channel.展开更多
Last year,the MTG(Magnet Technology Group)undertaken the magnet development formany accelerators such as High Intensity heavy ion Accelerator Facility(HIAF),China initiative Accelerator Driven System(CiADS),Space.Envi...Last year,the MTG(Magnet Technology Group)undertaken the magnet development formany accelerators such as High Intensity heavy ion Accelerator Facility(HIAF),China initiative Accelerator Driven System(CiADS),Space.Environment Simulation and Research Infrastructure(SESRI).展开更多
A new,compact and exible low energy experimental platform of highly charged ions(HCIs)based on an electron beam ion source of the Dresden EBIS-A type is presented.The so-called IMP EBIS-A Facility of the Institute of ...A new,compact and exible low energy experimental platform of highly charged ions(HCIs)based on an electron beam ion source of the Dresden EBIS-A type is presented.The so-called IMP EBIS-A Facility of the Institute of Modern Physics(IMP)in Lanzhou is designed as a user facility for the state-resolved charge exchange studies in HCIs with atoms and molecules collisions by cold target recoil ion momentum spectroscopy(COLTRIMS).展开更多
文摘目的验证基于临床CT的数字体相关(digital volume correlation,DVC)方法在测量股骨内部变形场时的准确性,并通过DVC进一步测量股骨在跌倒情况下的内部变形,验证基于临床CT的有限元分析方法(finite element analysis,FEA)在计算股骨内部变形场的准确性。方法使用猪股骨,模拟侧向跌倒姿态,进行分步力学加载实验,同步进行多次CT成像。通过重复扫描和虚拟位移验证DVC方法的准确性。DVC以子体积作为配准两组图像的研究对象,分别设置8、12、16和20 mm的子体积进行测试。量化误差指标包括位移系统误差-平均值(mean)、位移随机误差-标准差(standard deviation,SD)、应变准确度-平均绝对误差(mean absolute error,MAER)和应变精确度-标准差误差(standard deviation of the error,SDER)。基于CT图像建立股骨有限元模型,模拟实验条件,计算股骨内部位移,与DVC测量的内部变形场对比验证。结果基于临床CT的DVC方法重复扫描位移偏差小于0.013 mm,MAER和SDER均小于200με;虚拟位移偏差小于0.098 mm,MAER为1093~1687με,SDER为604~1267με,远小于骨组织屈服应变。FEA计算的位移和DVC测量的位移之间具有较强的相关性(R^(2)≥0.76,P<0.05)。结论基于临床CT的DVC方法可以准确测量股骨内部变形场,并且基于临床CT的有限元模型可以准确计算股骨内部变形场。
基金National Natural Science Foundation of China(11004202)
文摘The transfer ionization of atom by ion impact offers a very suitable test ground of quantum many-body problem[1],because the final state involves three particles (the projectile, the emitted electron and the recoil ion). The experimentaltechniques are available to perform kinematically complete measurements on these processes now.The experiment was performed using a reaction microscope at the Institute of Modern Physics, CAS[2]. Thedata was analyzed in terms of Dalitz spectrum which is presented in Fig. 1. In this figure, the Dalitz plot is
基金Major State Basic Research Development Program of China (973 Program, 2010CB832902) and National NaturalScience Foundation of China (10979007, 10974207, 11274317.)
文摘The reaction microscope (COLTRIMS as well) is a novel technique for the investigation of the dynamics ofion-atoms collisions. Exploiting this technique, a large variety of kinematically complete experiments on electrontransfer and ionization have been performed. However, the understanding of these experimental results is farfrom satisfactory, especially for collision energy in the intermediate-energy range. The classical-trajectory MonteCarlo method (CTMC) proposed by Abrines and Percival[1] shed some light on the problem. This method has ademonstrated region of applicability in the intermediate-energy range.
基金Major State Basic Research DevelopmentProgram of China (973 Program, 2010CB832902) and National Natural Science Foundation of China(11204322 and 10979007.)
文摘Electron induced ionization-excitation (IE) of helium is a basic four-body Coulomb problem in which all thefour charged particles are actively involved. It is much more challenging to both experiment and theory in contrastto direct ionization with the residual He+ ion in the ground state. The 2s or 2p separated TDCS data, especially atlow incident energy range where the high order effects are expected to play a significant role, would offer the moststringent test to theoretical models. However, only one experiment at high incident energy achieved the TDCSs for2p state till now due to the small cross section and the low detection efficiency for multi-coincidence events[1].
基金Major State Basic Research Development Program of China (973 Program, (2010CB832902), National NaturalScience Foundation of China under (10979007, 10974207, U1332128, 11004202). We would like to thank the engineers who operatedthe 320 kV platform for their assistance in running the ECR ion source
文摘The momentum projecting techniques have been well applied so as to explore the mechanisms of electronemissions as well as the dynamical effects which influenced the momentum distribution of the electrons ionized inion-atom collisions[1??3]. Usually, the emitted electrons will be projected onto the scattering plane, which was definedas the plane containing the initial and the final momentum vectors of the projectile, considering the conservationlaws and rotational symmetry around the beam axis. It is well known that the ejected electrons will be influencedsimultaneously by a combined coulomb potential from the recoil ions and the projectile ions. Qualitatively, this
基金National Natural Science Foundation of China (10979007, 91126004, 11274317)
文摘The cooling of heavy ions can provide high-quality beams that are especially important for high-precisionexperimental nuclear and atomic physics. The laser cooling of relativistic C3+ ion beams at the experimental coolerstorage ring (CSRe) is being currently prepared at Institute of Modern Physics (IMP) in Lanzhou. An electroncyclotron resonance ion source (ECRIS) will be used to produce C3+ ion beams. Meanwhile, O4+ ions could alsobe produced due to residual gas because of the same mass-to-charge ratio. Therefore, both C3+ and O4+ ion beamswill be injected and circulate in a storage ring during the laser cooling experiment at the same time. A higher ratioof C3+ ions will lead to a better result for the laser cooling experiment.
基金Major State Basic Research Development Program of China (973 Program, 2010CB832902), and National NaturalScience Foundation of China(10979007, 10974207, 11274317)
文摘We have investigated the single capture with simultaneous single ionization in He2+ collisions with argon bymeans of reaction microscopes[1]. Here, we report the dependence of the azimuth angle (φe) of the relatively high-energy electrons (kinetic energy > 20 eV) on the transversal recoil momentum (pr⊥) in single capture with doubleionization process for 30 keV/u He2+ collisions with Ar. It is noted that the relatively high-energy electrons mainlyresult from binary encounter (BE) between the target electrons and the projectiles for the present reaction channel.
文摘Last year,the MTG(Magnet Technology Group)undertaken the magnet development formany accelerators such as High Intensity heavy ion Accelerator Facility(HIAF),China initiative Accelerator Driven System(CiADS),Space.Environment Simulation and Research Infrastructure(SESRI).
基金National Key R&D Program of China(2017YFA0402400,2017YFA0402300)National Natural Science Foundation of China(11274317)。
文摘A new,compact and exible low energy experimental platform of highly charged ions(HCIs)based on an electron beam ion source of the Dresden EBIS-A type is presented.The so-called IMP EBIS-A Facility of the Institute of Modern Physics(IMP)in Lanzhou is designed as a user facility for the state-resolved charge exchange studies in HCIs with atoms and molecules collisions by cold target recoil ion momentum spectroscopy(COLTRIMS).
