A simulation model for phasic and phenological development of rice was developed using the scale of physiological development time, based on the ecophysiological development processes. The interaction of daily thermal...A simulation model for phasic and phenological development of rice was developed using the scale of physiological development time, based on the ecophysiological development processes. The interaction of daily thermal effectiveness, photoperiod effectiveness and intrinsic earliness(before heading), and basic filling duration factor(after heading)determined the daily physiological effectiveness, which accumulated to get physiological development time. The Beta and quadratic functions were used to describe daily thermal and photoperiod effectiveness, respectively. Five specific genetic parameters were added to adjust the genotypic differences in rice development so that all different varieties could reach the same physiological development time at a given development stage. The stages of seedling emergence, panicle initiation, heading, and maturity were validated using sowing dates under different ecological environments, with the RMSE of 1. 47, 5. 10, 4.58 and 3.37 days, respectively. The results showed that the model was not only explanatory and systematic but also accurate and applicable.展开更多
To predict the segregation effect in metal injection moulding (MIM) injection, a bi-phasic model based on mixture theory is adopted in simulation. An explicit algorithm is developed and realized by the authors, which ...To predict the segregation effect in metal injection moulding (MIM) injection, a bi-phasic model based on mixture theory is adopted in simulation. An explicit algorithm is developed and realized by the authors, which conducts the simulation to be a cost-effective tool in MIM technology. In case of the bi-phasic simulation, the viscosity behaviours are necessary to be determined for the flows of each phase while only the viscosity of mixture is measurable by tests. It is a crucial problem for application of the bi-phasic simulation of MIM injection. A reasonable method is hence analysed and proposed to determine the viscosity behaviours of each phase. Even though this method may be furthermore modified in the future, it results in the practical simulation of segregation effects with reasonable parameters. The simulation results are compared with the measurements on injected specimens.展开更多
Metal injection moulding (MIM) is a new technology to manufacture small intricate parts in large quantity. Numerical simulation plays an important role in its development. To predict the specific segregation effect in...Metal injection moulding (MIM) is a new technology to manufacture small intricate parts in large quantity. Numerical simulation plays an important role in its development. To predict the specific segregation effect in MIM injection, mixture theory is adopted to model the injection flow by a bi-phasic model. This model conducts to the solution of two-coupled Stokes equations. It is an extremely computational consuming solution in the scope of the traditional algorithms, which induce a serious challenge to cost-effectivity of the MIM simulation. Referred to some methods proposed by Lewis in mono-phasic simulation and the implicit algorithms in MIM simulation, a new explicit algorithm is proposed and realized to perform efficiently this type of bi-phasic flow. Numerically this algorithm is devised to perform the simulation in a fully uncoupled manner except for a global solution of the pressure field in each time step. The physical coupling is taken into account in a sequential pattern by fractional steps.展开更多
Airway hyperresponsiveness (AHR) is a characteristic feature of asthma, and generally correlates with severity of asthma. Understanding the protection mechanism against excessive airway narrowing and how it breaks dow...Airway hyperresponsiveness (AHR) is a characteristic feature of asthma, and generally correlates with severity of asthma. Understanding the protection mechanism against excessive airway narrowing and how it breaks down is fundamental to solving the problem of asthma. In this paper we have proposed a stochastic modeling the airway smooth muscle bundle for reproducing AHR such as an increased sensitivity of the airways to an inhaled constrictor agonist, a steeper slope of the dose-response curve, and a greater maximal response to agonist. A large number N of contractile muscle cells was assumed to repeat themselves in between contraction and relaxation asynchronously. Dynamic equilibrium of statistic physics was applied to the system of ASM bundle. Thus, the relation of dose to response of a piece of ASM bundle was described by Φ=tanh(βH) , where β was Boltzman factor and H represented energy of contraction induced by constrictor agents. Each of adjacent pair contractile cells was assumed to have Ising-type of antimagnetic interactions of preference energy J (for the condition of contraction-relaxation) between them. A motion equation for a piece of ASM bundle was described by Φ=N(H-zJΦ , which explained existence of combined tonic and phasic contractions. Based on observations of Venegas et al. [4], airway responsiveness was assumed to be assessable by total volume of the ventilation defects (TVD) of 13NN PET-CT images. Interactions via propagation of Ca ion waves between ASM bundles would cause percolation probability by PΦ=(1+tanh(βH))2/4 along the tree, then the relation of dose βH to TVD was described by TVD=PΦ[1-(1-PΦ)3/PΦ3]-TVD0. TVD0 represented the protection mechanism against excessive airway narrowing, which was determined by the ratio of amplitudes between tonic and phasic contractions, thus the balance of amplitudes between tonic and phasic contractions of peripheral lobular smooth muscles would be the determinant of AHR.展开更多
A variety of carbonyl compounds can be converted into oximes efficiently and conveniently in a novel ionic liquid/water bi-phasic system in the presence of sodium bicarbonate at ambient temperature. The ionic liquid 1...A variety of carbonyl compounds can be converted into oximes efficiently and conveniently in a novel ionic liquid/water bi-phasic system in the presence of sodium bicarbonate at ambient temperature. The ionic liquid 1-butyl-3-methyl imidazolium hexafluorophosphate [bmim]PF6 is immiscible with water or diethyl ether and can be easily recycled for reuse without noticeable droping in activity after separation of the products. The protocol is rapid, the yields are excellent, the method is simple and the ionic liquid can be reused.展开更多
A bi-phasic scaffold consisting of a columnar formaldehyde-acetalized polyvinyl alcohol (PVF) sponge and a cylindrical porous hydroxyapatite (HA) with a hollow center was devised. Rat bone marrow cells (rBMCs) were se...A bi-phasic scaffold consisting of a columnar formaldehyde-acetalized polyvinyl alcohol (PVF) sponge and a cylindrical porous hydroxyapatite (HA) with a hollow center was devised. Rat bone marrow cells (rBMCs) were seeded into the sponge placed in the hollow center of the cylindrical porous HA. The bi-phasic scaffold, a cylindrical porous HA and a PVF sponge separated from a bi-phasic scaffold after rBMC seeding, and a PVF sponge without rBMCs as a negative control, were implanted for 6 weeks into rat dorsal subcutaneous tissue. In each construct, bone formation was examined histologically and osteocalcin was measured immunochemically. Bone formation was observed in the bi-phasic scaffold and also in the cylindrical porous HA isolated from the bi-phasic scaffold. A significant difference in the quantity of osteocalcin was observed between the bi-phasic scaffold and the isolated cylindrical porous HA. No bone formation was found in the isolated PVF sponge. The bi-phasic scaffold as an outer layer of the scaffold seemed to inhibit the outflow of rBMCs from the PVF sponge. This type of bi-phasic scaffold may have two specific characteristics: Attachment of cells both in PVF sponge and cylindrical porous HA.展开更多
基金supported by the National Natura1 Science Foundation of China(30030090)the National 863 Program,China(2001AA245041)
文摘A simulation model for phasic and phenological development of rice was developed using the scale of physiological development time, based on the ecophysiological development processes. The interaction of daily thermal effectiveness, photoperiod effectiveness and intrinsic earliness(before heading), and basic filling duration factor(after heading)determined the daily physiological effectiveness, which accumulated to get physiological development time. The Beta and quadratic functions were used to describe daily thermal and photoperiod effectiveness, respectively. Five specific genetic parameters were added to adjust the genotypic differences in rice development so that all different varieties could reach the same physiological development time at a given development stage. The stages of seedling emergence, panicle initiation, heading, and maturity were validated using sowing dates under different ecological environments, with the RMSE of 1. 47, 5. 10, 4.58 and 3.37 days, respectively. The results showed that the model was not only explanatory and systematic but also accurate and applicable.
文摘To predict the segregation effect in metal injection moulding (MIM) injection, a bi-phasic model based on mixture theory is adopted in simulation. An explicit algorithm is developed and realized by the authors, which conducts the simulation to be a cost-effective tool in MIM technology. In case of the bi-phasic simulation, the viscosity behaviours are necessary to be determined for the flows of each phase while only the viscosity of mixture is measurable by tests. It is a crucial problem for application of the bi-phasic simulation of MIM injection. A reasonable method is hence analysed and proposed to determine the viscosity behaviours of each phase. Even though this method may be furthermore modified in the future, it results in the practical simulation of segregation effects with reasonable parameters. The simulation results are compared with the measurements on injected specimens.
基金Supported by the Invited Professor Program of French Ministry of Education (No. 9808588) , the French-Chinese Advanced Research Program (M98-04)the Foundation for University Key Teacher by the Chinese Ministry of Education (GG-460-10613-2770).
文摘Metal injection moulding (MIM) is a new technology to manufacture small intricate parts in large quantity. Numerical simulation plays an important role in its development. To predict the specific segregation effect in MIM injection, mixture theory is adopted to model the injection flow by a bi-phasic model. This model conducts to the solution of two-coupled Stokes equations. It is an extremely computational consuming solution in the scope of the traditional algorithms, which induce a serious challenge to cost-effectivity of the MIM simulation. Referred to some methods proposed by Lewis in mono-phasic simulation and the implicit algorithms in MIM simulation, a new explicit algorithm is proposed and realized to perform efficiently this type of bi-phasic flow. Numerically this algorithm is devised to perform the simulation in a fully uncoupled manner except for a global solution of the pressure field in each time step. The physical coupling is taken into account in a sequential pattern by fractional steps.
文摘Airway hyperresponsiveness (AHR) is a characteristic feature of asthma, and generally correlates with severity of asthma. Understanding the protection mechanism against excessive airway narrowing and how it breaks down is fundamental to solving the problem of asthma. In this paper we have proposed a stochastic modeling the airway smooth muscle bundle for reproducing AHR such as an increased sensitivity of the airways to an inhaled constrictor agonist, a steeper slope of the dose-response curve, and a greater maximal response to agonist. A large number N of contractile muscle cells was assumed to repeat themselves in between contraction and relaxation asynchronously. Dynamic equilibrium of statistic physics was applied to the system of ASM bundle. Thus, the relation of dose to response of a piece of ASM bundle was described by Φ=tanh(βH) , where β was Boltzman factor and H represented energy of contraction induced by constrictor agents. Each of adjacent pair contractile cells was assumed to have Ising-type of antimagnetic interactions of preference energy J (for the condition of contraction-relaxation) between them. A motion equation for a piece of ASM bundle was described by Φ=N(H-zJΦ , which explained existence of combined tonic and phasic contractions. Based on observations of Venegas et al. [4], airway responsiveness was assumed to be assessable by total volume of the ventilation defects (TVD) of 13NN PET-CT images. Interactions via propagation of Ca ion waves between ASM bundles would cause percolation probability by PΦ=(1+tanh(βH))2/4 along the tree, then the relation of dose βH to TVD was described by TVD=PΦ[1-(1-PΦ)3/PΦ3]-TVD0. TVD0 represented the protection mechanism against excessive airway narrowing, which was determined by the ratio of amplitudes between tonic and phasic contractions, thus the balance of amplitudes between tonic and phasic contractions of peripheral lobular smooth muscles would be the determinant of AHR.
基金The project was supported by the National Natural Science Foundation of China(No 20272018)the Guangdong Natural Science Foundation(No 021166,04010458)the Scientific Research Foundation for the Retumed Overseas Chinese Scholars,State Education Ministry of China.
文摘A variety of carbonyl compounds can be converted into oximes efficiently and conveniently in a novel ionic liquid/water bi-phasic system in the presence of sodium bicarbonate at ambient temperature. The ionic liquid 1-butyl-3-methyl imidazolium hexafluorophosphate [bmim]PF6 is immiscible with water or diethyl ether and can be easily recycled for reuse without noticeable droping in activity after separation of the products. The protocol is rapid, the yields are excellent, the method is simple and the ionic liquid can be reused.
文摘A bi-phasic scaffold consisting of a columnar formaldehyde-acetalized polyvinyl alcohol (PVF) sponge and a cylindrical porous hydroxyapatite (HA) with a hollow center was devised. Rat bone marrow cells (rBMCs) were seeded into the sponge placed in the hollow center of the cylindrical porous HA. The bi-phasic scaffold, a cylindrical porous HA and a PVF sponge separated from a bi-phasic scaffold after rBMC seeding, and a PVF sponge without rBMCs as a negative control, were implanted for 6 weeks into rat dorsal subcutaneous tissue. In each construct, bone formation was examined histologically and osteocalcin was measured immunochemically. Bone formation was observed in the bi-phasic scaffold and also in the cylindrical porous HA isolated from the bi-phasic scaffold. A significant difference in the quantity of osteocalcin was observed between the bi-phasic scaffold and the isolated cylindrical porous HA. No bone formation was found in the isolated PVF sponge. The bi-phasic scaffold as an outer layer of the scaffold seemed to inhibit the outflow of rBMCs from the PVF sponge. This type of bi-phasic scaffold may have two specific characteristics: Attachment of cells both in PVF sponge and cylindrical porous HA.
