The limiting performa nce analysis is used to study the optimal shock and impact isolation of mechanic al systems. The use of wavelets to approximate time-domain control functions is investigated. The formulation for...The limiting performa nce analysis is used to study the optimal shock and impact isolation of mechanic al systems. The use of wavelets to approximate time-domain control functions is investigated. The formulation for numerical computation is developed. Numerical examples include the optimal shock isolation of a SDOF system and the optimal i mpact isolation of a MDOF system. Computational results show that compactly supp orted wavelets can represent abrupt changes in control functions better than tri gonometric series and considerably increase computational efficiency.展开更多
The present paper narrates the influence of nonideality of externally controlled components on multiple-steady-state transitions studied by using the regular solution model. Under certain conditions the splitting of t...The present paper narrates the influence of nonideality of externally controlled components on multiple-steady-state transitions studied by using the regular solution model. Under certain conditions the splitting of the original cusp causes 'twin' bifurcation points accompanied by isolas which could shrink to an elliptic singular point or a cusp, or even collapse to a hyperbolic singular point in the different cases.展开更多
Chinese angelica [Angelica sinensis (Oily) Diels], a species of Umbelliferae, is an important medicinal herb.Its callus formatian and plant regeneration have been achieved in our laboratory. Study on protoplast cultur...Chinese angelica [Angelica sinensis (Oily) Diels], a species of Umbelliferae, is an important medicinal herb.Its callus formatian and plant regeneration have been achieved in our laboratory. Study on protoplast culture of this species has not yet been reported. In this paper we describe the successful culture of Chinese angelica protoplasts induced to form calli.展开更多
Di-er Cao, Hypericum japonicum Thunb (Guttiferae), is an annual herblet widely distributed in the South China and is used by the local people for the treatment of hepatitis. Phenolie extract of the plant has antimalar...Di-er Cao, Hypericum japonicum Thunb (Guttiferae), is an annual herblet widely distributed in the South China and is used by the local people for the treatment of hepatitis. Phenolie extract of the plant has antimalarial properties. Repeated chromatography of this extract on silica yields a crystalline phloroglucinol derivative named japonieine A (I) by us. The purified compound also shows good antimalarial activity in mice.展开更多
Two strains of influenza C viruses named C/Pig/Beijing/10/81 and C/Pig/Beijing/32/81 were isolated from abattoir pigs, and at the same time antibodies against influenza C virus were found in their sera. These results ...Two strains of influenza C viruses named C/Pig/Beijing/10/81 and C/Pig/Beijing/32/81 were isolated from abattoir pigs, and at the same time antibodies against influenza C virus were found in their sera. These results indicate that like influenza A, the influenza C virus can infect pigs. To our knowledge, this is the first report of such findings. Our work may provide an animal model for further studies on influenza C viruses and suggests that pigs may be hosts for all different types of influenza viruses.展开更多
This short communication uses numerical continuation to highlight the existence of an isola in a simple one-degree-of-freedom harmonically forced feedback system with actuator rate limiting as its only nonlinear eleme...This short communication uses numerical continuation to highlight the existence of an isola in a simple one-degree-of-freedom harmonically forced feedback system with actuator rate limiting as its only nonlinear element.It was found that the isola(1)contains only rate-limited responses,(2)merges with the main branch when the forcing amplitude is sufficiently large,and(3)includes stable solutions that create a second attractor in regions where rate limiting is not expected.Furthermore,the isola is composed of two solutions for a given forcing frequency.These solutions have the same amplitudes in the state(pitch rate)projection;however,they have distinct phases,and their amplitudes are also distinct when projected onto the integrator state in the controller.The rich dynamics observed in such a simple example underlines the impact of rate limiting on feedback systems.Specifically,the combination of feedback and rate limiting can create detrimental dynamics that is hard to predict and requires careful analysis.展开更多
文摘The limiting performa nce analysis is used to study the optimal shock and impact isolation of mechanic al systems. The use of wavelets to approximate time-domain control functions is investigated. The formulation for numerical computation is developed. Numerical examples include the optimal shock isolation of a SDOF system and the optimal i mpact isolation of a MDOF system. Computational results show that compactly supp orted wavelets can represent abrupt changes in control functions better than tri gonometric series and considerably increase computational efficiency.
文摘The present paper narrates the influence of nonideality of externally controlled components on multiple-steady-state transitions studied by using the regular solution model. Under certain conditions the splitting of the original cusp causes 'twin' bifurcation points accompanied by isolas which could shrink to an elliptic singular point or a cusp, or even collapse to a hyperbolic singular point in the different cases.
文摘Chinese angelica [Angelica sinensis (Oily) Diels], a species of Umbelliferae, is an important medicinal herb.Its callus formatian and plant regeneration have been achieved in our laboratory. Study on protoplast culture of this species has not yet been reported. In this paper we describe the successful culture of Chinese angelica protoplasts induced to form calli.
文摘Di-er Cao, Hypericum japonicum Thunb (Guttiferae), is an annual herblet widely distributed in the South China and is used by the local people for the treatment of hepatitis. Phenolie extract of the plant has antimalarial properties. Repeated chromatography of this extract on silica yields a crystalline phloroglucinol derivative named japonieine A (I) by us. The purified compound also shows good antimalarial activity in mice.
文摘Two strains of influenza C viruses named C/Pig/Beijing/10/81 and C/Pig/Beijing/32/81 were isolated from abattoir pigs, and at the same time antibodies against influenza C virus were found in their sera. These results indicate that like influenza A, the influenza C virus can infect pigs. To our knowledge, this is the first report of such findings. Our work may provide an animal model for further studies on influenza C viruses and suggests that pigs may be hosts for all different types of influenza viruses.
文摘This short communication uses numerical continuation to highlight the existence of an isola in a simple one-degree-of-freedom harmonically forced feedback system with actuator rate limiting as its only nonlinear element.It was found that the isola(1)contains only rate-limited responses,(2)merges with the main branch when the forcing amplitude is sufficiently large,and(3)includes stable solutions that create a second attractor in regions where rate limiting is not expected.Furthermore,the isola is composed of two solutions for a given forcing frequency.These solutions have the same amplitudes in the state(pitch rate)projection;however,they have distinct phases,and their amplitudes are also distinct when projected onto the integrator state in the controller.The rich dynamics observed in such a simple example underlines the impact of rate limiting on feedback systems.Specifically,the combination of feedback and rate limiting can create detrimental dynamics that is hard to predict and requires careful analysis.
