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In angiosperms, seed size is a critical trait that is influenced by the complex interplay between the endosperm and seed coat. The HAIKU (IKU) pathway, involving the transcription factor WRKY10, plays a crucial role in regulating seed size in Arabidopsis thaliana. However, the downstream targets of WRKY10 and their roles in seed size determination remain largely unexplored. Here, we identified LACCASE2 (LAC2), a laccase gene involved in lignin biosynthesis, as a new downstream target of WRKY10. We observed that the expression of LAC2 was upregulated in the mini3 mutant, which is defective in WRKY10. We demonstrated that WRKY10 directly binds to the promoter of miR397a, activating its expression. miR397a, in turn, represses the expression of LAC2. Genetic analyses revealed that a mutation in LAC2 or overexpression of miR397a partially rescued the small seed phenotype of the MINISEED3 (MINI3) mutant mini3. Conversely, the overexpression of LAC2 in the wild type led to a decrease in seed size. These findings suggest that LAC2 functions as a negative regulator of seed size, and its expression is modulated by WRKY10 through miR397a. Our study uncovers a novel WRKY10-miR397a-LAC2 pathway that regulates seed size in Arabidopsis, providing new insights into the complex regulatory network governing seed development in plants. [ABSTRACT FROM AUTHOR]

Transport and cycling of dissolved organic carbon (DOC) are most active in estuaries. However, a comprehensive understanding of the sources, sinks, and transformation processes of DOC throughout the river-estuary-ocean continuum is yet to be derived. Taking the Changjiang Estuary and adjacent shelf sea as a case study area, this study applies a physics-biogeochemistry coupled model to investigate DOC cycling the river-estuary-ocean continuum. DOC is classified into two types depending on the origin, namely terrigenous DOC (tDOC) and marine DOC (mDOC). Simulation results were compared with observation and showed a satisfactory model performance. Our study indicates that in summer, the distribution of DOC in the Changjiang Estuary is driven by both hydrodynamics and biogeochemical processes, while in winter, it is primarily driven by hydrodynamics. The spatial transition from terrigenous-dominated DOC to marine-dominated DOC occurs mainly across the contour line of a salinity of 20 PSU. Additionally, the source-sink patterns in summer and winter are significantly different, and the gradient changes in chlorophyll-a indicate the transition between sources and sinks of DOC. A five-year averaged budget analysis of the model results indicates that the Changjiang Estuary has the capability to export DOC, with tDOC contributing 31 % and mDOC accounting for 69 %. The larger proportion of mDOC is primarily attributed to local biogeochemical processes. The model offers a novel perspective on the distribution of DOC in the Changjiang Estuary and holds potential for its application in future organic carbon cycling of other estuaries. [ABSTRACT FROM AUTHOR]

Adjustments in vehicle height and attitude under high-speed steering, emergency obstacle avoidance, and obstacle crossing can significantly improve the safety, mobility, and passing ability of a vehicle. At present, air and hydraulic suspensions are generally used for vehicle body height adjustment, both of which have problems of slow response and complex structures. In this study, a novel method of vehicle body height adjustment based on active suspension with a permanent magnet synchronous linear motor (PMSLM) is proposed. First, active suspension and PMSLM models are established. Then, the vehicle body height controller is designed by hierarchical control, where the upper layer uses PI control to make the vehicle body height track the desired vehicle body height and calculate the desired control force, whereas the lower layer uses the finite control set model predictive current control to make the linear motor track the desired suspension control force. For motor control, the cost function is constructed based on the minimum tracking error between the reference and predicted currents. The forward Euler discrete method is used to deduce the current prediction model for the linear motor. The simulation tests under different road classes and vehicle speeds prove that the active suspension with the PMSLM can effectively adjust the vehicle body height and has a fast response, simple structure, and does not affect ride comfort. The proposed method provides a new concept for short-term vehicle body height adjustments under specific working conditions. [ABSTRACT FROM AUTHOR]

The rolling control of car focus usually on reducing the roll angle passively. This control has the limited performance for increasing handing stability,passing speed,ride comfort and preventing rollover when the car is turning. This project proposes a control methodology to control the automobile to roll toward the turning direction by using the active suspension. A 6-DOF vehicle model with a 2-DOF steering model and a 4-DOF roll model is established. The active roll sliding mode controller which makes the steady-state roll angle error be zero is established after the desired roll angle is established by dynamic analysis. The simulation results confirm the effectiveness of the control method. The controller makes the perceived lateral acceleration and the lateral load transfer rate be greatly reduced,which effectively improves the handling stability,ride comfort,and the vehicle speed when vehicle is turning,and makes the possibility of rollover be decreased extremely.

For suspension systems with asymmetric damping during the extension and compression strokes, the equilibrium position of the vehicle body will lift or drop. Inspired by this phenomenon, a novel idea of control the vehicle height by adjusting asymmetric damping via adjustable-damping semi-active suspensions is proposed. Meanwhile, a methodology to implement this idea is also presented. By accounting for nonlinear factors, such as the nonlinear constraints of the output damping force of an adjustable-damper and the logic control conditions of the asymmetric damping adjustment, this control system was designed as a hybrid system. Hybrid model predictive control theory was used to design this controller, and the switching control problem was transformed into a continuous-rolling finite-time-domain optimisation control problem. The feasibility of this idea was proven by simulations for single-wheel vehicle height control. The proposed idea makes it possible to use semi-active actuators for vehicle height adjustment to realise the control effect achieved by active actuators. Moreover, it has lower energy consumption, lower cost and faster response than active suspension, and provides a new method for short-term vehicle height and attitude control under some specific vehicle conditions, such as high-speed steering, and emergency obstacle avoidance, etc. [ABSTRACT FROM AUTHOR]

The asymmetrical damping of a vibration-isolation system induces a change in the mean position of the isolated body. Inspired by this phenomenon, a novel idea to vertically shift an isolated body based on nonlinear system vibration with asymmetrical damping is proposed. The proposed idea can be applied in fields that require the isolated body's height to be adjusted. A methodology based on the homotopy analysis method (HAM), which is used to obtain the approximate analytical solution of a piecewise-smooth vibration-isolation system, was developed to verify the feasibility of the proposed idea. The accuracy of the solution obtained by the HAM was verified by the Runge–Kutta method. Furthermore, based on the analytical solution, the effects of critical parameters on the vibration responses of the system were analyzed. Finally, the proposed idea was applied to vehicle height adjustments. Simulation results showed that vehicle height adjustments could be realized only using a semi-active suspension. This provides a novel methodology for vehicle height control. [ABSTRACT FROM AUTHOR]

One of the important factors affecting the performances of semi-active suspension control is how to obtain the terrain information. A preliminary study is conducted to detect and memory the road conditions by which semi-active suspension switches control strategies or certain damping from one to another. The suspension adopts skyhook controllers designed for halfvehicle model in random road and uses small damping while passing an obstacle. The navigator advance informs the suspension controller as soon as it detects obstacles in front. Then the controller switches to small damping,thereby reducing the peak vibration and improve driving ride. Simulation proves the validity of this idea. Experiment using a real car is conducted after an onboard navigation system developed and the road conditions detection and memory search strategies are available. The experiment and simulation achieve similar results.