Variation of Plant Electrophysiology in Cucumber under Different Water Status

AP and VP were measured in cucumbers under water sufficiency and water stress. The results indicated that, the AP would be evoked by electrical impulse, for water-stressed cucumber, its amplitude could reached more than 40 mV which was obviously greater than that (about 10-20 mV) of plant under well-watered, and no VP came out. Along with the intensity of light increased, the VP appeared going-up trend, and accompanied by evidently spiking electrical signal, for plant under water stress, the VP increased more clearly, but the change of spiking amplitude of AP (about 3 mV) was rather smaller than that (8-10 mV) of plant under well-watered.

A New Method for the Atomic Ground-State Energy in the Screened Coulomb Potential

The new method proposed recently by Friedberg,Lee and Zhao is applied to the derivation of the atomic ground-state energy with the inclusion of the screening effect.The present results are compared with those obtained in the pure Coulomb potential and by the variational approach.The overall good results are obtained with this new method.

Electrical wave transmission in healthy black pine seedlings

Non-injurious local stimuli, such as a cold shock, and injurious stimuli, such as local burning, punctures or chemicals, were applied to study electrical wave transmission in black pine (Pinus thunbergii) seedlings. The results showed that non-injurious stimuli evoked the action potential (AP) transmission and injurious stimulation induced both AP transmission and the more complex variation (VP) transmission in the seedlings. The causes of these phenomena were discussed. Key words Black pine - Pinus thunbergii - Action potential (AP) - Variation potential (VP) - Electrical wave transmission CLC number S791.256 Document code A Foundation item: This paper was supported by the National Nature Science Foundation of China (grant No. 39670613).Biography: GUO Jian (1971-), male, lecturer in Haikou Bureau of Forestry. Hainan, P. R. China.Responsible editor: Song Funan

Effect of temporal variation rate of cross polar cap potential on the equatorial ionospheric vertical drift: A statistical study

Based on the equatorial vertical ion drift measured by DMSP and cross polar cap potential （Фcpc） from AMIE output during 2001 to 2003, this paper investigates the relationship of Фcpc and its temporal variation rate （△Фcpc） with the disturbed ion velocity （△Vx） which is the difference between the disturbed days （Kp〉4） and quiet days （Kp〈2）. The statistical analysis shows： （1） The △Vx correlates better with AФcpc than with Фcpc, indicating that the electric field penetration is more easily to occur when solar wind input rapidly varies with time. （2） The optimal delay time of electric field penetration from the high-latitude magnetosphere to equatorial ionosphere has local time dependence which is longer on the nightside than on the dayside. It may be due to more complicated electrodynamic process on the nightside. （3） With the linear relationship between △Фcpc and △Vx, it is obtained that the penetration efficiency is about 4.5%-13.9% at day and 31%-42% at night, coinciding well with former studies.

A nonlinear rheological model of backfill material for retaining roadways and the analysis of its stability

The long-term stability of backfill material is the key to retaining roadways successfully. In order to study the rheological deformation of backfill material and its long-term stability, given the visco-elastoplastic properties of this material, we introduced a softening and a hardening function for a new nonlinear the- ological model with time-varying parameters. Based on this, we presented the instability condition of this model by using the principle of minimum potential energy. Combined with engineering practice, we cal- culated the urlstable time period of backfill material. The results show that the time of instability of the backfill material relate to the initial parameters of the material, ＂the coefficients decided by temperature and the ratio of the plastic zone of the backfill material. Based on the results of our analysis from the point of view of energy, we can quickly obtain the time of instability of this model from our graphical analysis. The time of instability of the backfill material obtained from our investigation coincides with an actual project.

EXISTENCE RESULTS FOR DEGENERATE ELLIPTIC EQUATIONS WITH CRITICAL CONE SOBOLEV EXPONENTS

In this paper, we study the existence result for degenerate elliptic equations with singular potential and critical cone sobolev exponents on singular manifolds. With the help of the variational method and the theory of genus, we obtain several results under different conditions.

Control Method of Three-level Neutral-point-clamped Inverter Based on Voltage Vector Diagram Partition

A new modulation approach was presented for the control of neutral-point （NP） voltage variation in the three-level NP-clamped voltage source inverter, and the average NP current model was established based on vector diagram partition. Thus, theory base was built for balancing control of NP potential. Theoretical analysis and experimental results indicate that the proposed method for NP balancing control vector synthe- sizing concept based can make the average NP current zero, and do not influence NP potential within every sample period. The effectiveness of proposed research approach was verified by simulative and experimental results.

Mechanics analysis of thin-walled box continuous girder with variable cross-sections in considering effect of large deflection and shear lag

In order to study the mechanics behavior of a thin-walled box continuous girder with variable crosssections,using potential variation theories,considering the effect of shear lag of flange’s stress and the nonlinear geometry of vertical displacement,and evolving five generalized displacements with the spline function,the large deflection problem of the thin-walled box continuous girder with variable cross-section was transformed to a nonlinear algebraic equation,which was solved using the Newton-Raphon iterative method.The results of the calculation show that different shear lag warp functions to the cantilever,top and bottom plate should be taken to analyze the mechanics behavior of the thin-walled box continuous girder reliably.The thin-walled box continuous girder with variable cross-sections has more reasonable stress state and is more adaptable for the longitudinal change of internal forces than that with equal crosssections.The effect of large deflection on the stress and displacement of the thin-walled box continuous girder with variable cross-sections depends on the values of the load.