Suspension culture of Taxus chinensis was used as a model plant cell system to study the effects of pulsed electric field (PEF) on cell growth and the biosynthesis of secondary metabolites. Different exposure time of PEF had different effects on Taxus chinensis cells in different cell growth phases. Significant intracellular enhanced accumulation of taxuyunnanine C (Tc, a bioactive secondary metabolite) was observed by exposing the cells in early exponential growth phase to a 30 min PEF. The Tc content increased by 30% after exposure to PEF, without any loss of dry cell weight compared with that of the control. Moreover, combination of PEF with sucrose feeding showed a great synergistic accumulative effect on secondary metabolite production.
The control chart based on the geometric distribution(g-type chart )has been shown to be competitive with p or np chart for monitoring the proportion,especially for applications in high quality manufacturing environments.However when the cases with LCL=0 occur, plotting values beneath the LCL is impossible given the non-negative nature of units such type of lower control limit has no ability to detect rate increase. In fact,situation with a LCL is not uncommon. In this paper we propose the g-type chart with asymmetric control limits.It is found that with the nonzero LCL,the power to detect rate increase has much improved and the power to detect rate decrease is nearly fixed, while the in-control average run length(ARL)is the almost the same as the conventional(symmetric) control chart. In practice,the quantitative results of the paper can be used to determined the control limits.
Based on the principles of landscape ecology and applied GIS techniques, the performance of ecological suitability was analysed for Xiamen city.According to the demands of urban development planning to land-use the relationship among economical development, urban landscape and environmental protection was studied. Then, a landscape eco-planning was proposed for Xiamen city, which divided Xiamen city into four eco-functional zones and the main attributes, the major function and strategies of regulation and control for each zone were described accordingly. This landscape eco-planning would serve a scientific basis for the economical development, environmental protection and the foundation of “eco-city of bay type”, as well as a sound guideline for the eco-landscape planning of Chinese costal zones.
Some new results are obtained for the oscillatory, bounded and monotone properties of solutions of forced second-order quaslinear equation (p(t -τ )(y'(t - τ))α)' = q(t)yβ(t) + r(t),t ≥ t0, where,t0 and τ are all nonnegative real numbers, when t ≥ t0,p(t) is a postive real continuous function,r(t) is a real continuous function, q(t) is a nonnegative real continuous function and q(t)is not zero function , α and β are quotients of odd positive integers.
This paper deals with the problem of obust and non-fragile H∞ control for uncertain tochastic discrete-delay large-scale systems. The ncertainties of the system are assumed to be time-varying norm-bounded. The aim is the design of a robust and non-fragile H∞ decentralized state feedback controller for the systems with additive controller gain variations,which ensures the robust stochastic stability and a prescribed H∞ performance level for the resulting closed-loop system, in spite of the uncertainties and the time delays. Based on the Lyapunov method, a sufficient condition for the existence of such a state feedback controller is obtained in terms of linear matrix inequalities(LMIs).
Composite structured samples of glass-coated Fe-based nanocrystalline wires deposited with a layer of copper by magnetron sputtering method were prepared. The giant magneto-impedance effect (GMI) observed from the samples was carried out as ac driving current flowed through ferromagnetic core, copper shell, and both of the core and shell, respectively. It is found that the maximum GMI frequency decreases from 80 MHz to 60 MHz with copper layer when the current flows through ferromagnetic core. The onset GMI freqwency is also decreased. The results show the electromagnetic interaction between the shell layer and the core.
中国综合性科技类核心期刊(北大核心)
