Component content distribution profile control in rare earth countercurrent extraction process

Considering that the on-line measurement and automatic control of element component content(ECC) are difficult to perform in rare earth cascade extraction process, the ECC distribution profile is dynamically regulated at all stages to assess the effect of product purity control. Focusing on the theory of countercurrent extraction, the technology parameters and pre-setting flow-rates during the extract process are designed. Under varying process parameters, a novel step by step model is also proposed for each stage to analyze the impact on the distribution profile change. Combining the mass balance model and ECC changing trend at the monitoring stage, the ECC distribution profile can be automatically regulated by dynamically compensating the related extract or scrubbing liquid flow-rate. To this end, the required product purity at the two outlets is achieved. Based on Wincc and Matlab dynamic simulators, a specific Pr/Nd cascade extraction process is used to illustrate and demonstrate the application of the present approach.

THE PIGMENT-PROTEIN COMPLEXES OF HIGHER PLANTS MIGRATION IN THYLAKOID AND THE REGULATION OF LIGHT ENERGY DISTRIBUTION BETWEEN PHOTOSYSTEMS

Appressed and non-appressed lamella membranes of Castor bean leaf chloroplasts were separated by non-ionic detergent Triton-X 100.Appressed membranes showed a high oxygen-evolving activity and low chl a/b ratio. Examining with SDS-PTGE and liquid nitrogen temperature fluorescence measurement showed that they contained only PSII and light-harvesting pigment-protein complexes (LHCP),and there was no detectable amount of PSI. Freeze-fracture electromicroscopic observation confirmed that this part was really an appressed lamella membrane. Through divalent cation Mg^(++), the thylakoid membranes were induced to unstack and restack.With the addition of Mg^(++), the fluorescence intensity was changed instantly. We realized that there existed two processes:One was a rapid process which was accomplished within 30 s. The other was a slow process of which the time duration was about 60 min. This dual effects of Mg^(++) had not been reported before.We had analyzed the change of F685/F730 and discussed the possible rneehanis ms of light energy distribution between photosystems.

Optimal Dispatch for Battery Energy Storage Station in Distribution Network Considering Voltage Distribution Improvement and Peak Load Shifting

Distribution networks are commonly used to demonstrate low-voltage problems.A new method to improve voltage quality is using battery energy storage stations(BESSs),which has a four-quadrant regulating capacity.In this paper,an optimal dispatching model of a distributed BESS considering peak load shifting is proposed to improve the voltage distribution in a distribution network.The objective function is to minimize the power exchange cost between the distribution network and the transmission network and the penalty cost of the voltage deviation.In the process,various constraints are considered,including the node power balance,single/two-way power flow,peak load shifting,line capacity,voltage deviation,photovoltaic station operation,main transformer capacity,and power factor of the distribution network.The big M method is used to linearize the nonlinear variables in the objective function and constraints,and the model is transformed into a mixed-integer linear programming problem,which significantly improves the model accuracy.Simulations are performed using the modified IEEE 33-node system.A typical time period is selected to analyze the node voltage variation,and the results show that the maximum voltage deviation can be reduced from 14.06%to 4.54%.The maximum peak-valley difference of the system can be reduced from 8.83 to 4.23 MW,and the voltage qualification rate can be significantly improved.Moreover,the validity of the proposed model is verified through simulations.

Homogenous lithium plating/stripping regulation by a mass-producible Zn particles modified Li-metal composite anode

A stable lithium-metal anode is critical for high performance lithium-metal batteries. However, heterogeneous Li plating/stripping may induce lithium dendrites formation on bare lithium-metal anode, which lowers the cell Coulombic efficiency and weakens battery safety. We found that bare Li metal surface becomes bumpy and cratered with numerous pits formation during Li stripping. These pits enhance electric field distortion and heterogeneous ion distribution during plating. Li plating preferentially happens on the edge of the pits, intensifying the voltage variation and Li dendrites growth, which leads to the cell rapid death or separator piercing. Herein, we propose a facile and mass-producible method to homogenize Li plating/stripping via adding lithiophilic particles into Li metal. Zinc particles were uniformly pressed in Li metal by a facile and scalable physical strategy of “rolling”, and transformed into LiZn alloy in situ through Li-Zn alloying at room temperature in a few minutes. The critical role of modified LiZn/Li composite anode in stabilizing electrode surface was revealed by both electrochemical test and simulation. Compared with bare Li anode, the evenly dispersed LiZn alloy particles in Li metal can effectively regulate the Li plating/stripping on electrode surface, reducing deepness of pits during stripping and directionally inducing Li plating to maintain electrode surface stability. On this basis, the pits depth of LiZn/Li composite during Li stripping is reduced to ∼ 15 μm, which is much shallower than that of bare Li metal of ∼ 40 μm. The LiZn/Li composite electrode can stably cycle for 600 h under Li plating/stripping capacity of 1 mAh·cm−2 and current density of 1 mA·cm−2 without any short circuit. Furthermore, assembled LiZn/Li||LiFePO4 full cell presents better cycling stability and rate performances than that of based on bare Li anode.

NaMYB8 regulates distinct,optimally distributed herbivore defense traits

When herbivores attack, plants specifically reconfigure their metabolism. Herbivory on the wild tobacco Nicotiana attenuata strongly induces the R2R3 MYB transcriptional activator MYB8, which was reported to specifically regulate the accumulation of phenolamides （PAs）. We discovered that transcriptional regulation of trypsin protease inhibitors （TPIs） and a threonine deaminase （TD） also depend on MYB8 expression. Induced distributions of PAs, TD and TPIs all meet predictions of optimal defense theory： their leaf concentrations increase with the fitness value and the probability of attack of the tissue. Therefore, we suggest that these defensive compounds have evolved to be co-regulated by MYB8.