In order to continuously analyze the whole fine-blanking process, from the beginning of the operation up to the total rupture of the sheet-metal, without computational divergence, a 3-D rigid visco-plastic finite-elem...In order to continuously analyze the whole fine-blanking process, from the beginning of the operation up to the total rupture of the sheet-metal, without computational divergence, a 3-D rigid visco-plastic finite-element method based on Gurson void model was developed. The void volume fraction was introduced into the finite element method to document the ductile fracture of the sheet-metal. A formulation of variation of the rigid visco-plastic material was presented according to the virtual work theory in which both the effects of equivalent stress and hydrostatic pressure in the deformation process were considered. The crack initiation of the sheet was predicted and the crack propagation was geometrically fulfilled in the simulation by separating the nodes according to the stress state. Furthermore, the influences of different state-variables on the deformation process were also studied.展开更多
Sol-gel method was employed for the preparation of nanoscale tungsten powder. The effects of different preparation conditions on particle size were discussed and the optimum preparation condition was found. The produc...Sol-gel method was employed for the preparation of nanoscale tungsten powder. The effects of different preparation conditions on particle size were discussed and the optimum preparation condition was found. The products were characterized by X-ray diffraction, scan electron microscopy and so on. The results show that the intermediate is monoclinic WO3, its particle shape is approximately spherical, and the particle size distribution is narrow. The average particle size is about 60 nm. After deoxidization, WO3 turns into cubic tungsten powder with small particle size （average particle size about 120 nm） and narrow size distribution.展开更多
We proposed an empirical equation for a fine-structure constant: . Then, . where m<sub>p</sub> and m<sub>e</sub> are the rest mass of a proton and the rest mass of an electron, respectively. In...We proposed an empirical equation for a fine-structure constant: . Then, . where m<sub>p</sub> and m<sub>e</sub> are the rest mass of a proton and the rest mass of an electron, respectively. In this report, using the electrochemical method, we proposed an equivalent circuit. Then, we proposed a refined version of our own old empirical equations about the electromagnetic force and gravity. Regarding the factors of 9/2 and π, we used 3.132011447 and 4.488519503, respectively. The calculated values of T<sub>c</sub> and G are 2.726312 K and 6.673778 × 10<sup>-11</sup> (m<sup>3</sup>⋅kg<sup>-1</sup>⋅s<sup>-2</sup>).展开更多
AIM To evaluate the efficacy of endoscopic ultrasoundguided fine needle aspiration(EUS-FNA) of pancreatic head cancer when pushing(push method) or pulling the echoendoscope(pull method).METHODS Overall, 566 pancreatic...AIM To evaluate the efficacy of endoscopic ultrasoundguided fine needle aspiration(EUS-FNA) of pancreatic head cancer when pushing(push method) or pulling the echoendoscope(pull method).METHODS Overall, 566 pancreatic cancer patients had their first EUS-FNA between February 2001 and December 2017. Among them, 201 who underwent EUS-FNA for pancreatic head lesions were included in this study. EUS-FNA was performed by the push method in 85 patients, the pull method in 101 patients and both the push and pull methods in 15 patients. After propensity score matching(age, sex, tumor diameter, and FNA needle), 85 patients each were stratified into the push and pull groups. Patient characteristics and EUSFNA-related factors were compared between the two groups.RESULTS Patient characteristics were not significantly different between the two groups. The distance to lesion was significantly longer in the push group than in the pull group(13.9 ± 4.9 mm vs 7.0 ± 4.9 mm, P < 0.01). The push method was a significant factor influencing the distance to lesion(≥ median 10 mm)(P < 0.01). Additionally, tumor diameter ≥ 25 mm(OR = 1.91, 95%CI: 1.02-3.58, P = 0.043) and the push method(OR = 1.91, 95%CI: 1.03-3.55, P = 0.04) were significant factors contributing to the histological diagnosis of malignancy.CONCLUSION The pull method shortened the distance between the endoscope and the lesion and facilitated EUS-FNA of pancreatic head cancer. The push method contributed to the histological diagnosis of pancreatic head cancer using EUS-FNA specimens.展开更多
A physical value mapping （PVM） algorithm based on finite element mesh from the stamped part in stamping process to the product is presented, In order to improve the efficiency of the PVM algorithm, a search way from...A physical value mapping （PVM） algorithm based on finite element mesh from the stamped part in stamping process to the product is presented, In order to improve the efficiency of the PVM algorithm, a search way from the mesh of the product to the mesh of the stamped part will be adopted. At the same time, the search process is divided into two steps： entire search （ES） and local search （LS）, which improve the searching efficiency. The searching area is enlarged to avoid missing projection elements in ES process. An arc-length method is introduced in LS process. The validity is confirmed by the results of the complex industry-forming product.展开更多
Homogeneous BaTiO3 fine powder has been synthesized at (80°C) by using three different chemical methods using the roots TiCl4, BaCl2 and NaOH or Oxalic acid. The resultant powders were characterized using x-ray d...Homogeneous BaTiO3 fine powder has been synthesized at (80°C) by using three different chemical methods using the roots TiCl4, BaCl2 and NaOH or Oxalic acid. The resultant powders were characterized using x-ray diffraction (XRD) to estimate the crystal structure, lattice parameters and the crystallite size to investigate the favor method in producing BaTiO3 fine powder. The criteria that was dependent on considering the favor method that was given better results of XRD and demand a least time in preparation which tend to consume a lowest energy.展开更多
A comprehensive theoretical study of correlation effects on the fine-structure splitting within the ground configuration 3d9 of the Co-like HI45＋, Ta46＋, W47＋, and Au52＋ ions is performed by employing the multi-co...A comprehensive theoretical study of correlation effects on the fine-structure splitting within the ground configuration 3d9 of the Co-like HI45＋, Ta46＋, W47＋, and Au52＋ ions is performed by employing the multi-configuration Dirac-Hartree- Fock method in the active space approximation. It shows that the core-valence correlation with the inner-core 2p electron is more significant than with the outer 3p and 3s electrons, and the correlation with the 2s electron is also noticeable. The core-core correlation seems to be small and can be ignored. The calculated 2D3/2,5/2 splitting energies agree with the recent electron-beam ion-trap measurements [Phys. Rev. A 83 032517 （2011）, Eur. Phys. J. D 66 286 （2012）] to within the experimental uncertainties.展开更多
In X-ray absorption fine structure(XAFS) experiments,Soller slits are widely used as filter devices in order to improve the signal to noise ratio.Performing high accuracy manual focusing operations is a time-consuming...In X-ray absorption fine structure(XAFS) experiments,Soller slits are widely used as filter devices in order to improve the signal to noise ratio.Performing high accuracy manual focusing operations is a time-consuming process;therefore,this work introduces an automatic focusing method for Soller slits in multi-element fluorescence detectors.This method establishes a relation model between the fluorescence intensity distribution and the coordinates of the fluorescence excitation point.According to this relation model,the actual coordinates of the fluorescence excitation point can be deduced from the detected fluorescence intensity distribution and used in focusing operations.This method has proven to be feasible in an XAFS experiment at the BL14W1 beamline of the Shanghai Synchrotron Radiation Facility.展开更多
文摘In order to continuously analyze the whole fine-blanking process, from the beginning of the operation up to the total rupture of the sheet-metal, without computational divergence, a 3-D rigid visco-plastic finite-element method based on Gurson void model was developed. The void volume fraction was introduced into the finite element method to document the ductile fracture of the sheet-metal. A formulation of variation of the rigid visco-plastic material was presented according to the virtual work theory in which both the effects of equivalent stress and hydrostatic pressure in the deformation process were considered. The crack initiation of the sheet was predicted and the crack propagation was geometrically fulfilled in the simulation by separating the nodes according to the stress state. Furthermore, the influences of different state-variables on the deformation process were also studied.
文摘Sol-gel method was employed for the preparation of nanoscale tungsten powder. The effects of different preparation conditions on particle size were discussed and the optimum preparation condition was found. The products were characterized by X-ray diffraction, scan electron microscopy and so on. The results show that the intermediate is monoclinic WO3, its particle shape is approximately spherical, and the particle size distribution is narrow. The average particle size is about 60 nm. After deoxidization, WO3 turns into cubic tungsten powder with small particle size （average particle size about 120 nm） and narrow size distribution.
文摘We proposed an empirical equation for a fine-structure constant: . Then, . where m<sub>p</sub> and m<sub>e</sub> are the rest mass of a proton and the rest mass of an electron, respectively. In this report, using the electrochemical method, we proposed an equivalent circuit. Then, we proposed a refined version of our own old empirical equations about the electromagnetic force and gravity. Regarding the factors of 9/2 and π, we used 3.132011447 and 4.488519503, respectively. The calculated values of T<sub>c</sub> and G are 2.726312 K and 6.673778 × 10<sup>-11</sup> (m<sup>3</sup>⋅kg<sup>-1</sup>⋅s<sup>-2</sup>).
文摘AIM To evaluate the efficacy of endoscopic ultrasoundguided fine needle aspiration(EUS-FNA) of pancreatic head cancer when pushing(push method) or pulling the echoendoscope(pull method).METHODS Overall, 566 pancreatic cancer patients had their first EUS-FNA between February 2001 and December 2017. Among them, 201 who underwent EUS-FNA for pancreatic head lesions were included in this study. EUS-FNA was performed by the push method in 85 patients, the pull method in 101 patients and both the push and pull methods in 15 patients. After propensity score matching(age, sex, tumor diameter, and FNA needle), 85 patients each were stratified into the push and pull groups. Patient characteristics and EUSFNA-related factors were compared between the two groups.RESULTS Patient characteristics were not significantly different between the two groups. The distance to lesion was significantly longer in the push group than in the pull group(13.9 ± 4.9 mm vs 7.0 ± 4.9 mm, P < 0.01). The push method was a significant factor influencing the distance to lesion(≥ median 10 mm)(P < 0.01). Additionally, tumor diameter ≥ 25 mm(OR = 1.91, 95%CI: 1.02-3.58, P = 0.043) and the push method(OR = 1.91, 95%CI: 1.03-3.55, P = 0.04) were significant factors contributing to the histological diagnosis of malignancy.CONCLUSION The pull method shortened the distance between the endoscope and the lesion and facilitated EUS-FNA of pancreatic head cancer. The push method contributed to the histological diagnosis of pancreatic head cancer using EUS-FNA specimens.
基金This project is supported by National Natural Science Foundation ofChina(No.l9832020) and National Outstanding Youth Science Foundation ofChina(No.10125208).
文摘A physical value mapping （PVM） algorithm based on finite element mesh from the stamped part in stamping process to the product is presented, In order to improve the efficiency of the PVM algorithm, a search way from the mesh of the product to the mesh of the stamped part will be adopted. At the same time, the search process is divided into two steps： entire search （ES） and local search （LS）, which improve the searching efficiency. The searching area is enlarged to avoid missing projection elements in ES process. An arc-length method is introduced in LS process. The validity is confirmed by the results of the complex industry-forming product.
文摘Homogeneous BaTiO3 fine powder has been synthesized at (80°C) by using three different chemical methods using the roots TiCl4, BaCl2 and NaOH or Oxalic acid. The resultant powders were characterized using x-ray diffraction (XRD) to estimate the crystal structure, lattice parameters and the crystallite size to investigate the favor method in producing BaTiO3 fine powder. The criteria that was dependent on considering the favor method that was given better results of XRD and demand a least time in preparation which tend to consume a lowest energy.
基金supported by the National Natural Science Foundation of China(Grant Nos.11076009 and 11374062)the Chinese Association of Atomic and Molecular Data+1 种基金the Chinese National Fusion Project for ITER(Grant No.2015GB117000)the Leading Academic Discipline Project of Shanghai City,China(Grant No.B107)
文摘A comprehensive theoretical study of correlation effects on the fine-structure splitting within the ground configuration 3d9 of the Co-like HI45＋, Ta46＋, W47＋, and Au52＋ ions is performed by employing the multi-configuration Dirac-Hartree- Fock method in the active space approximation. It shows that the core-valence correlation with the inner-core 2p electron is more significant than with the outer 3p and 3s electrons, and the correlation with the 2s electron is also noticeable. The core-core correlation seems to be small and can be ignored. The calculated 2D3/2,5/2 splitting energies agree with the recent electron-beam ion-trap measurements [Phys. Rev. A 83 032517 （2011）, Eur. Phys. J. D 66 286 （2012）] to within the experimental uncertainties.
基金supported by National Nature Science Foundation of China(No.11175244)
文摘In X-ray absorption fine structure(XAFS) experiments,Soller slits are widely used as filter devices in order to improve the signal to noise ratio.Performing high accuracy manual focusing operations is a time-consuming process;therefore,this work introduces an automatic focusing method for Soller slits in multi-element fluorescence detectors.This method establishes a relation model between the fluorescence intensity distribution and the coordinates of the fluorescence excitation point.According to this relation model,the actual coordinates of the fluorescence excitation point can be deduced from the detected fluorescence intensity distribution and used in focusing operations.This method has proven to be feasible in an XAFS experiment at the BL14W1 beamline of the Shanghai Synchrotron Radiation Facility.
