The effects of the length of solenoid coil on tube compression in electromagnetic forming were investigated either by theory analysis or through sequential coupling numerical simulation. The details of the electromagn...The effects of the length of solenoid coil on tube compression in electromagnetic forming were investigated either by theory analysis or through sequential coupling numerical simulation. The details of the electromagnetic and the mechanical models in the simulation were described. The results show that the amplitude of coil current waveform and the current frequency decrease with the increase of the coil length. And the peak value of magnetic pressure is inversely proportional to the coil length. The distribution of the magnetic force acting on the tube is inhomogeneous while the tube is longer than the coil. The shortened coil length causes the increases of the maximum deformation and energy efficiency. The numerically calculated result and the experimental one of the final tube profile are in good agreement.展开更多
The two-step hydro-bulge forming technique was proposed to manufacture the ellipsoidal shell with the length ratio of the long axis to the short axis larger than 1.4. A central tube was introduced into the first step ...The two-step hydro-bulge forming technique was proposed to manufacture the ellipsoidal shell with the length ratio of the long axis to the short axis larger than 1.4. A central tube was introduced into the first step of the hydro-bulge forming process to constrain the over growth of the short axis during bulging,and then the central tube was replaced with two polar plates in the second step of the hydro-bulge forming process to manufacture an integral ellipsoidal shell. It is shown that the central tube restricts the growth of the short axis and simultaneously reduces the shrunk tendency of the long axis. The wrinkling occurs due to the latitudinal compressive stress at the equator at the early stage of hydro-bulge forming. However,with the increase of internal pressure,the compressive stress areas gradually decrease and finally the tensile latitudinal stress occupies approximately the whole shell,thus the wrinkles are eliminated. A sound ellipsoidal shell with the axis length ratio of 1.8 is obtained after two-step hydro bulging.展开更多
Purpose: To investigate the effects of intravitreal injection of cyclopentolate on form deprivation myopia in guinea pigs. Methods: Thirty-five guinea pigs at age of 3 weeks were randomly divided into 5 groups (n = 7 ...Purpose: To investigate the effects of intravitreal injection of cyclopentolate on form deprivation myopia in guinea pigs. Methods: Thirty-five guinea pigs at age of 3 weeks were randomly divided into 5 groups (n = 7 for each group): deprived, deprived plus saline, deprived plus cyclopentolate, normal control, and cyclopentolate group. Form deprivation was only performed in right eyes with translucent membranes for 4 weeks. Physiological saline and cyclopentolate were intravitreally injected into deprived eyes at four-day intervals. All the left eyes remained untreated as group control. Refraction was measured by retinoscopy after cycloplegia. The axial dimensions were measured by A-scan ultrasound. Subsequently, retinal histology was observed by light microscopy. Results: After 4 weeks of treatment, intravitreal injection of cyclopentolate significantly reduced the degree of myopia in the deprived eyes (from -3.92 D to -0.86 D, P < 0.001), and retarded the increase of vitreous chamber depth (from 3.83 ± 0.06 mm to 3.70 ± 0.05 mm, P < 0.001) and axial length (from 8.42 ± 0.04 mm to 8.30 ± 0.05 mm, P < 0.001) in the deprived eyes. Histological ex-amination revealed no evidence of retinal damage of eyes injected with physiological saline or cy-clopentolate compared with normal control eyes. Conclusions: Intravitreal administration of cy-clopentolate reduces axial elongation of the deprived eyes in guinea pigs. Further investigations are required to identify the optimal dose.展开更多
The current study performed a finite element analysis of the strain localization behavior of a voided ductile material using a non-local plasticity formulation in which the yield strength depends on both an equivalent...The current study performed a finite element analysis of the strain localization behavior of a voided ductile material using a non-local plasticity formulation in which the yield strength depends on both an equivalent plastic strain measurement (hardening parameter) and Laplacian equivalent. The introduction of gradient terms to the yield function was found to play an important role in simulating the strain localization behavior of the voided ductile material. The effect of the mesh size and characteristic length on the strain localization were also investigated. An FEM simulation based on the proposed non-local plasticity revealed that the load-strain curves of the voided ductile material subjected to plane strain tension converged to one curve, regardless of the mesh size. In addition, the results using non-local plasticity also exhibited that the dependence of the deformation behavior of the material on the mesh size was much less sensitive than that with classical local plasticity and could be successfully eliminated through the introduction of a large value for the characteristic length.展开更多
The generalized oscillator strengths (GOSs) of 2p63s0 (3p, 4p, 5p, 6p) states excited from sodium ground state in Debye plasma, are studied by two kinds of theoretical approaches: the restricted Hartree-Fock (RHF) met...The generalized oscillator strengths (GOSs) of 2p63s0 (3p, 4p, 5p, 6p) states excited from sodium ground state in Debye plasma, are studied by two kinds of theoretical approaches: the restricted Hartree-Fock (RHF) method and the random phase approximation with exchange (RPAE). Wavefunctions of the ground state and the excited states are calculated numerically from the RHF equation, employing the local density approach for exchange interaction including, in extension, plasma screening effects. The GOSs have been computed by using these wavefunctions. The results of RHF and RPAE calculations of the GOS for different Debye lengths have been reported for sodium dipole excitation to 3s0 (3p, 4p, 5p, 6p). We show, in this study, that RPAE results for values of Debye length D = 30, 100, ∞ are in excellent agreement with those found by other authors. The results of RPAE calculations show that correlation effects are quite significant around the maxima GOS for the excitations to 3s0 (4p, 5p, 6p) but are found to have no great influence in the GOS for the dipole excitation to 3s03p. We find that the amplitude of the GOS has noticeably been reduced in going from higher to lower Debye length. We’ve observed here that the peak of the GOS shifts towards a small momentum transfer when the value D = 20 a.u is taken. These results show an important influence of the Debye plasma screening interactions on the GOS as the screening Debye length is decreased.展开更多
We analyzed the relationship between internode number and intemode length for one of the largest bamboo, Phyllostachys pubescens Mazel ex Houz. For 50 sample culms with various sizes felled in a pure stand of P. pubes...We analyzed the relationship between internode number and intemode length for one of the largest bamboo, Phyllostachys pubescens Mazel ex Houz. For 50 sample culms with various sizes felled in a pure stand of P. pubescens, the intemode number was assigned from base to tip and the length for each internode was directly measured. The result indicated that the intemode length should be cumulated from base to tip, and then the cumulated internode length should be relativized by the total culm length. It was inappropriate to relativize the internode length by the maximum intenode length. In addition, the relationship between the relative internode number （the intemode number relativized by the total number of intemodes） and the relative cumulated internode length should be described not by a power function but by a sigmoid function such as the third-order function. The determined function enabled us to estimate the actual internode length, with the root mean squared error being 4 cm. In conclusion, the mathematical expression presented here, i.e., the relativization of the cumulated internode length by the total culm length and the application of the sigmoid function, will be useful in describing the relationship between internode number and internode length for P. pubescens.展开更多
Ear morphological traits such as volume and shape are important features of maize and the quantitative associations among them can help understand kernel yield determination. 150 mature ears each of 4 maize cultivars ...Ear morphological traits such as volume and shape are important features of maize and the quantitative associations among them can help understand kernel yield determination. 150 mature ears each of 4 maize cultivars were collected from field experiments, and ear length(L), diameter(D), area(S) and volume(V) were recorded for individual ears, kernel weight per ear also recorded for a portion of the examined ears. Following principles of dimensional analysis, 8 theoretical equations of 3 sets,which relate ear higher dimensions to its length and diameter, were developed and parameterized and validated with the field observations. The 3 optimized equations showed that the shape of ears in maize can be featured with 3 dimensionless form factors, namely diameter-to-length ratio(c=D/L), areal form factor(b=S/L/D), and volumetric form factor(a=V/L/D/D). Statistically,all of them were significantly different among cultivars, and a's values varied from 0.582 to 0.612, and b's 0.839-0.868, and c's 0.242-0.308. Volumetric form factor and areal form factor could estimate precisely ear volume and area respectively, but diameter-to-length ratio was not suitable to estimate ear diameter by its length. Ear volume explained almost all variation of ear kernel weight and product L*D*D did the same substantially. Dimensional analysis proved to be promising in understanding relationship among morphological traits of ears in maize. Its application in crop researches should improve our knowledge of the physical properties of crop plants.展开更多
基金Project(50575052) supported by the National Natural Science Foundation of China
文摘The effects of the length of solenoid coil on tube compression in electromagnetic forming were investigated either by theory analysis or through sequential coupling numerical simulation. The details of the electromagnetic and the mechanical models in the simulation were described. The results show that the amplitude of coil current waveform and the current frequency decrease with the increase of the coil length. And the peak value of magnetic pressure is inversely proportional to the coil length. The distribution of the magnetic force acting on the tube is inhomogeneous while the tube is longer than the coil. The shortened coil length causes the increases of the maximum deformation and energy efficiency. The numerically calculated result and the experimental one of the final tube profile are in good agreement.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 59975022 and 50275034)
文摘The two-step hydro-bulge forming technique was proposed to manufacture the ellipsoidal shell with the length ratio of the long axis to the short axis larger than 1.4. A central tube was introduced into the first step of the hydro-bulge forming process to constrain the over growth of the short axis during bulging,and then the central tube was replaced with two polar plates in the second step of the hydro-bulge forming process to manufacture an integral ellipsoidal shell. It is shown that the central tube restricts the growth of the short axis and simultaneously reduces the shrunk tendency of the long axis. The wrinkling occurs due to the latitudinal compressive stress at the equator at the early stage of hydro-bulge forming. However,with the increase of internal pressure,the compressive stress areas gradually decrease and finally the tensile latitudinal stress occupies approximately the whole shell,thus the wrinkles are eliminated. A sound ellipsoidal shell with the axis length ratio of 1.8 is obtained after two-step hydro bulging.
文摘Purpose: To investigate the effects of intravitreal injection of cyclopentolate on form deprivation myopia in guinea pigs. Methods: Thirty-five guinea pigs at age of 3 weeks were randomly divided into 5 groups (n = 7 for each group): deprived, deprived plus saline, deprived plus cyclopentolate, normal control, and cyclopentolate group. Form deprivation was only performed in right eyes with translucent membranes for 4 weeks. Physiological saline and cyclopentolate were intravitreally injected into deprived eyes at four-day intervals. All the left eyes remained untreated as group control. Refraction was measured by retinoscopy after cycloplegia. The axial dimensions were measured by A-scan ultrasound. Subsequently, retinal histology was observed by light microscopy. Results: After 4 weeks of treatment, intravitreal injection of cyclopentolate significantly reduced the degree of myopia in the deprived eyes (from -3.92 D to -0.86 D, P < 0.001), and retarded the increase of vitreous chamber depth (from 3.83 ± 0.06 mm to 3.70 ± 0.05 mm, P < 0.001) and axial length (from 8.42 ± 0.04 mm to 8.30 ± 0.05 mm, P < 0.001) in the deprived eyes. Histological ex-amination revealed no evidence of retinal damage of eyes injected with physiological saline or cy-clopentolate compared with normal control eyes. Conclusions: Intravitreal administration of cy-clopentolate reduces axial elongation of the deprived eyes in guinea pigs. Further investigations are required to identify the optimal dose.
文摘The current study performed a finite element analysis of the strain localization behavior of a voided ductile material using a non-local plasticity formulation in which the yield strength depends on both an equivalent plastic strain measurement (hardening parameter) and Laplacian equivalent. The introduction of gradient terms to the yield function was found to play an important role in simulating the strain localization behavior of the voided ductile material. The effect of the mesh size and characteristic length on the strain localization were also investigated. An FEM simulation based on the proposed non-local plasticity revealed that the load-strain curves of the voided ductile material subjected to plane strain tension converged to one curve, regardless of the mesh size. In addition, the results using non-local plasticity also exhibited that the dependence of the deformation behavior of the material on the mesh size was much less sensitive than that with classical local plasticity and could be successfully eliminated through the introduction of a large value for the characteristic length.
文摘The generalized oscillator strengths (GOSs) of 2p63s0 (3p, 4p, 5p, 6p) states excited from sodium ground state in Debye plasma, are studied by two kinds of theoretical approaches: the restricted Hartree-Fock (RHF) method and the random phase approximation with exchange (RPAE). Wavefunctions of the ground state and the excited states are calculated numerically from the RHF equation, employing the local density approach for exchange interaction including, in extension, plasma screening effects. The GOSs have been computed by using these wavefunctions. The results of RHF and RPAE calculations of the GOS for different Debye lengths have been reported for sodium dipole excitation to 3s0 (3p, 4p, 5p, 6p). We show, in this study, that RPAE results for values of Debye length D = 30, 100, ∞ are in excellent agreement with those found by other authors. The results of RPAE calculations show that correlation effects are quite significant around the maxima GOS for the excitations to 3s0 (4p, 5p, 6p) but are found to have no great influence in the GOS for the dipole excitation to 3s03p. We find that the amplitude of the GOS has noticeably been reduced in going from higher to lower Debye length. We’ve observed here that the peak of the GOS shifts towards a small momentum transfer when the value D = 20 a.u is taken. These results show an important influence of the Debye plasma screening interactions on the GOS as the screening Debye length is decreased.
基金supported in part by the fiscal 2010 special grant from the president of the Prefectural University of Kumamoto
文摘We analyzed the relationship between internode number and intemode length for one of the largest bamboo, Phyllostachys pubescens Mazel ex Houz. For 50 sample culms with various sizes felled in a pure stand of P. pubescens, the intemode number was assigned from base to tip and the length for each internode was directly measured. The result indicated that the intemode length should be cumulated from base to tip, and then the cumulated internode length should be relativized by the total culm length. It was inappropriate to relativize the internode length by the maximum intenode length. In addition, the relationship between the relative internode number （the intemode number relativized by the total number of intemodes） and the relative cumulated internode length should be described not by a power function but by a sigmoid function such as the third-order function. The determined function enabled us to estimate the actual internode length, with the root mean squared error being 4 cm. In conclusion, the mathematical expression presented here, i.e., the relativization of the cumulated internode length by the total culm length and the application of the sigmoid function, will be useful in describing the relationship between internode number and internode length for P. pubescens.
基金Supported by the National Natural Science Foundation of China(31271658)National Key Research and Development Program of China(2016YFD0300306)
文摘Ear morphological traits such as volume and shape are important features of maize and the quantitative associations among them can help understand kernel yield determination. 150 mature ears each of 4 maize cultivars were collected from field experiments, and ear length(L), diameter(D), area(S) and volume(V) were recorded for individual ears, kernel weight per ear also recorded for a portion of the examined ears. Following principles of dimensional analysis, 8 theoretical equations of 3 sets,which relate ear higher dimensions to its length and diameter, were developed and parameterized and validated with the field observations. The 3 optimized equations showed that the shape of ears in maize can be featured with 3 dimensionless form factors, namely diameter-to-length ratio(c=D/L), areal form factor(b=S/L/D), and volumetric form factor(a=V/L/D/D). Statistically,all of them were significantly different among cultivars, and a's values varied from 0.582 to 0.612, and b's 0.839-0.868, and c's 0.242-0.308. Volumetric form factor and areal form factor could estimate precisely ear volume and area respectively, but diameter-to-length ratio was not suitable to estimate ear diameter by its length. Ear volume explained almost all variation of ear kernel weight and product L*D*D did the same substantially. Dimensional analysis proved to be promising in understanding relationship among morphological traits of ears in maize. Its application in crop researches should improve our knowledge of the physical properties of crop plants.
