The Effects of Temperature, Light and Moisture on the Seed Germination of Siphonostegia chinensis Benth

To explore the optimum temperature,light intensityand water conditions for seed germination of Siphonostegia chinensis Benth.,seed germination experiment were carried out under different temperatures(5/15,10/20,15/25,20/30℃),different light intensity(14h light/10h darkness,complete darkness)and different concentrations(0%,5%,10%,15%,20%)of PEG-6000 solution.In terms of concentration,5%PEG was regarded as the low level,10%and 15%as the medium level,and 20%as the high level.The results showed that(1)Germination rate,germination potential,and germination index were increased with the rise of temperature.In addition,seed germination was significantly higher under the dark conditions than that with the 14h light/10h darkness.(2)No seed germination occurred when the temperature was below 10/20 C at 14h light/10h darkness.(3)Under 14h light/10h darkness,the germination rate,germination potential and germination index first increased and then decreased with the increase of PEG concentration.The low concentration was more beneficial to the seed germination.(4)Under the condition of complete darkness,the germination rate,germination potential and germination index decline with fluctuation with the increase of PEG concentration.Seed germination of Siphonostegia chinensis Benth.was inhibited in high concentration of PEG.

Effects of Exogenous Calcium on Datura Seed Germination under Drought Stress

With polyethylene glycol(PEG-6000),of 0%(CK),5%,10%,15%,25%used to simulate drought stress,and CaCl2 concentration 0(CK),of 15,20,25 and 30mmol/L as ion gradient of exogenous calcium,the effects of drought,exogenous calcium and the interaction between the two on the Datura seed germination,so as to explore the optimal application amount of exogenous calcium to ease the suppression of drought stress on Datura seed germination.The results showed that the germination rate,germination potential and germination index of the Datura seeds were significantly lower than those of the control group.Under the normal moisture condition,exogenous calcium of moderate and low concentration had no significant effect on the Datura seed germination,while that of high concentration showed an inhibitory effect on the seed germination.Under drought stress,with the increasing concentration of exogenous calcium,the three indicators of Datura seeds showed a trend of increasing first and then decreasing.When the exogenous calcium had the concentration of 20 mmol/L,all the indicators of seed germination reached the maximum value,while showed a downward trend when exogenous calcium concentration was 25-30 mmol/L,and even increasingly sharp with drought intensifying.Therefore,in the production and utilization of Datura,20 mmol/L of exogenous calcium can be used to soak seeds before sowing to improve the emergence rate under low and moderate drought conditions.

Numerical and theoretical analysis on soil arching effect of prefabricated piles as deep foundation pit supports

This study presents a detailed investigation into the soil arching effects within deep foundation pits(DFPs),focusing on their mechanical behavior and implications for structural design.Through rigorous 3D finite element modeling and parameter sensitivity analyses,the research explores the formation,geometric characteristics,and spatial distribution of soil arching phenomena.The investigation encompasses the influence of key parameters such as elastic modulus,cohesion,and internal friction angle on the soil arching effect.The findings reveal that soil arching within DFPs exhibits distinct spatial characteristics,with the prominent arch axis shifting as excavation depth progresses.Optimal soil arching is observed when the pile spacing approximates three times the pile diameter,enhancing soil retention and minimizing deformation risks.Sensitivity analyses highlight the significant impact of soil parameters on soil arching behavior,underscoring the critical role of cohesive forces and internal friction angles in shaping arching characteristics.By elucidating the interplay between soil parameters and soil arching effects,the research provides insights for optimizing pile spacing and structural stability.

基于改进LCCD算法的高分六号WFV数据云检测研究

高分六号WFV是搭载在我国高分六号卫星上的高空间分辨率多光谱传感器,该传感器实现了高分辨率和宽覆盖的结合。精确识别高分六号WFV数据的云像元对于农业资源监测、林业资源调查以及防灾减灾等行业具有重要意义。基于全球土地覆盖产品FROM-GLC10数据,改进地表类型支持的云检测算法(LCCD算法),开展了高分六号WFV数据的云检测工作。以FROM-GLC10作为先验数据,充分考虑不同地表类型反射率的变化,在每种地表类型上分别采用不同的方法设置阈值。通过目视解译的方法对云检测结果进行精度评价,云正确率整体达到了92.46%,其中植被类、水体类、高亮地表类的云正确率分别为93.09%、95.60%和88.70%。结果表明,改进的基于地表类型的云检测算法有效提高了高分六号WFV数据云检测的精度。

Lyapunov-based switched-gain impact angle control guidance

To hit stationary ground targets in specified direction, a nonlinear impact angle control guidance law based on Lyapunov stability theory is proposed. The proposed law ensures the convergence of the heading angle and the miss distance to guarantee a successful engagement. The impact angle can be adjusted by varying a single parameter. And the maximum value of acceleration has been analyzed to get the proper range for control parameter. Considering the achievable impact angle set is limited, an additional phase is added to form a two-phase control strategy.The first phase is to establish a proper initial condition for the second phase, and the second phase is to hit the target with a certain impact angle. An analysis of the proper selection of control parameters to expand the achievable impact angle set is presented. The performance of the proposed guidance law is illustrated with simulations.

RLSESN-based PID adaptive control for a novel wearable rehabilitation robotic hand driven by PM-TS actuators

Purpose-The purpose of this paper is to develop a novel wearable rehabilitation robotic hand driven by Pneumatic Muscle-Torsion Spring(PM-TS)for finger therapy.PM has complex nonlinear dynamics,which makes PM modelling difficult.To realize high-accurate tracking for the robotic hand,an Echo State Network(ESN)-based PID adaptive controller is proposed,even though the plant model is unknown.Design/methodology/approach-To drive a single joint of rehabilitation robotic hand,the paper proposes a new PM-TS actuator comprising a Pneumatic Muscle(PM)and a Torsion Spring(TS).Based on the novel actuator,a wearable robotic hand is designed.By employing the model-free approximation capability of ESN,the RLSESN based PID adaptive controller is presented for improving the trajectory tracking performance of the rehabilitation robotic hand.An ESN together with Recursive Least Square(RLS)is called a RLSESN,where the ESN output weight matrix is updated by the online RLS learning algorithm.Findings–Practical experiments demonstrate the validity of the PM-TS actuator and indicate that the performance of the RLSESN based PID adaptive controller is better than that of the conventional PID controller.In addition,they also verify the effectiveness of the proposed rehabilitation robotic hand.Originality/value–A new PM-TS actuator configuration that uses a PM and a torsion spring for bi-directional movement of joint is presented.By utilizing the new PM-TS actuator,a novel wearable rehabilitation robotic hand for finger therapy is designed.Based on the unknown plant model,the RLSESN_PID controller is proposed to attain satisfactory performance.

Ascent Trajectory Optimization for Air-Breathing Hypersonic Vehicles Based on IGS-MPSP

This paper proposes an improved Generalized Quasi-Spectral Model Predictive Static Programming(GS-MPSP)algorithm for the ascent trajectory optimization for hypersonic vehicles in a complex°ight environment.The proposed method guarantees the satisfaction of constraints related to the state and control vector while retaining its high computational e±ciency.The spectral representation technique is used to describe the control variables,which reduces the number of decision variables and makes the control input smooth enough.Through Taylor expansion,the constraints are transformed into an inequality containing only decision variables,such that it can be added into GS-MPSP framework.By Gauss quadrature collocation method,only a few collocation points are needed to solve the sensitivity matrix,which greatly accelerates the calculation.Subsequently,the analytical expression is obtained by combining the static optimization with the penalty function method.Finally,the simulation results demonstrate that the proposed improved GS-MPSP algorithm can achieve both high computational e±-ciency and high terminal precision under the constraints..

Cloning of the Aspergillus awamori glucoamylase gene and expression in Saccharomyces cerevisiae

The A. awamori glucoamylase I gene was obtained by RT_PCR and inserted into the plasmid pAC1. We constructed an expression vector pAC1_GA, which was used to transform the yeast S. cerevisiae AS 2 1364 without auxotrophic marker. The transformant secreted glucoamylase into the medium efficiently and degraded starch. The glucoamylase activity of the culture filtrate is up to 8 4 U/mL.