Integrative analysis of the metabolome and transcriptome reveals the potential mechanism of fruit flavor formation in wild hawthorn(Crataegus chungtienensis)

Hawthorns are important medicinal and edible plants with a long history of health protection in China.Besides cultivated hawthorn,other wild hawthorns may also have excellent medicinal and edible value,such as Crataegus chungtienensis,an endemic species distributed in the Southwest of China.In this study,by integrating the flavor-related metabolome and transcriptome data of the ripening fruit of C.chungtienensis,we have developed an understanding of the formation of hawthorn fruit quality.The results show that a total of 849 metabolites were detected in the young and mature fruit of C.chungtienensis,of which flavonoids were the most detected metabolites.Among the differentially accumulated metabolites,stachyose,maltotetraose and cis-aconitic acid were significantly increased during fruit ripening,and these may be important metabolites affecting fruit flavor change.Moreover,several flavonoids and terpenoids were reduced after fruit ripening compared with young fruit.Therefore,using the unripe fruit of C.chungtienensis may allow us to obtain more medicinal active ingredients such as flavonoids and terpenoids.Furthermore,we screened out some differentially expressed genes(DEGs)related to fruit quality formation,which had important relationships with differentially accumulated sugars,acids,flavonoids and terpenoids.Our study provides new insights into flavor formation in wild hawthorn during fruit development and ripening,and at the same time this study lays the foundation for the improvement of hawthorn fruit flavor.

Online Identification of Lithium-ion Battery Model Parameters with Initial Value Uncertainty and Measurement Noise

Online parameter identification is essential for the accuracy of the battery equivalent circuit model(ECM).The traditional recursive least squares(RLS)method is easily biased with the noise disturbances from sensors,which degrades the modeling accuracy in practice.Meanwhile,the recursive total least squares(RTLS)method can deal with the noise interferences,but the parameter slowly converges to the reference with initial value uncertainty.To alleviate the above issues,this paper proposes a co-estimation framework utilizing the advantages of RLS and RTLS for a higher parameter identification performance of the battery ECM.RLS converges quickly by updating the parameters along the gradient of the cost function.RTLS is applied to attenuate the noise effect once the parameters have converged.Both simulation and experimental results prove that the proposed method has good accuracy,a fast convergence rate,and also robustness against noise corruption.

A Research on Emergency DC Power Support Based on DCOI

An integrated scheme of emergency DC power support which is based on dominant center of Inertia DCOI is proposed to improve power system transient stability. The inter-area speed differences equivalent by dominant center of inertia alleviates the main weakness of the traditional signal which is made of the frequencies at both sides and is represent of abnormal information of the nonlinear dynamic behavior of the power system based on a model in which two AC systems are connected by a HVDC Link. Sichuan Power Grid connected with Southwest Power Grid by Deyang-Baoji HVDC project is used to testify the method. The simulation results show that the control strategy can significantly advance the transient stability of AC/DC system through extended equal area criterion (EEAC).

A Novel Location Method for Interline Power Flow Controllers Based on Entropy Theory

As one of the new generation flexible AC transmission systems(FACTS)devices,the interline power flow controller(IPFC)has the significant advantage of simultaneously regulating the power flow of multiple lines.Nevertheless,how to choose the appropriate location for the IPFC converters has not been discussed thoroughly.To solve this problem,this paper proposes a novel location method for IPFC using entropy theory.To clarify IPFC’s impact on system power flow,its operation mechanism and control strategies of different types of serial converters are discussed.Subsequently,to clarify the system power flow characteristic suitable for device location analysis,the entropy concept is introduced.In this process,the power flow distribution entropy index is used as an optimization index.Using this index as a foundation,the power flow transfer entropy index is also generated and proposed for the IPFC location determination study.Finally,electromechanical electromagnetic hybrid simulations based on ADPSS are implemented for validation.These are tested in a practical power grid with over 800 nodes.A modular multilevel converter(MMC)-based IPFC electromagnetic model is also established for precise verification.The results show that the proposed method can quickly and efficiently complete optimized IPFC location and support IPFC to determine an optimal adjustment in the N-1 fault cases.

Impact of Grid Topology on Pole-to-ground Fault Current in Bipolar DC Grids:Mechanism and Evaluation

The fault current level analysis is important for bipolar direct current(DC)grids,which determines the operation and protection requirements.The DC grid topology significantly impacts the current path and then the fault current level of the grid,which makes it possible to limit the fault current by optimizing the grid topology.However,the corresponding discussion in the literature is indigent.Aiming at this point,the impact of grid topology,i.e.,the connecting scheme of converters,on the pole-to-ground fault current in bipolar DC grids,is investigated in this paper,and the ground-return-based and metallic-return-based grounding schemes are considered,respectively.Firstly,the decoupled equivalent model in frequency domain for fault current analysis is obtained.Then,the impacts of converters with different distances to the fault point on the fault current can be analyzed according to the high-frequency impedance characteristics.Based on the analysis results,a simplified fault current index(SFCI)is proposed to realize the fast evaluation of impact of grid topology on the fault current level.The SFCI is then applied to evaluate the relative fault current level.Finally,the simulation results validate the model,the analysis method,and the SFCI,which can effectively evaluate the relative fault current level in a direct and fast manner.