Dynamic optimal allocation of energy storage systems integrated within photovoltaic based on a dual timescale dynamics model

Energy storage systems(ESSs)operate as independent market participants and collaborate with photovoltaic(PV)generation units to enhance the flexible power supply capabilities of PV units.However,the dynamic variations in the profitability of ESSs in the electricity market are yet to be fully understood.This study introduces a dual-timescale dynamics model that integrates a spot market clearing(SMC)model into a system dynamics(SD)model to investigate the profit-aware capacity growth of ESSs and compares the profitability of independent energy storage systems(IESSs)with that of an ESS integrated within a PV(PV-ESS).Furthermore,this study aims to ascertain the optimal allocation of the PV-ESS.First,SD and SMC models were set up.Second,the SMC model simulated on an hourly timescale was incorporated into the SD model as a subsystem,a dual-timescale model was constructed.Finally,a development simulation and profitability analysis was conducted from 2022 to 2040 to reveal the dynamic optimal range of PV-ESS allocation.Additionally,negative electricity prices were considered during clearing processes.The simulation results revealed differences in profitability and capacity growth between IESS and PV-ESS,helping grid investors and policymakers to determine the boundaries of ESSs and dynamic optimal allocation of PV-ESSs.

Siamese Dense Pixel-Level Fusion Network for Real-Time UAV Tracking

Onboard visual object tracking in unmanned aerial vehicles(UAVs)has attractedmuch interest due to its versatility.Meanwhile,due to high precision,Siamese networks are becoming hot spots in visual object tracking.However,most Siamese trackers fail to balance the tracking accuracy and time within onboard limited computational resources of UAVs.To meet the tracking precision and real-time requirements,this paper proposes a Siamese dense pixel-level network for UAV object tracking named SiamDPL.Specifically,the Siamese network extracts features of the search region and the template region through a parameter-shared backbone network,then performs correlationmatching to obtain the candidate regionwith high similarity.To improve the matching effect of template and search features,this paper designs a dense pixel-level feature fusion module to enhance the matching ability by pixel-wise correlation and enrich the feature diversity by dense connection.An attention module composed of self-attention and channel attention is introduced to learn global context information and selectively emphasize the target feature region in the spatial and channel dimensions.In addition,a target localization module is designed to improve target location accuracy.Compared with other advanced trackers,experiments on two public benchmarks,which are UAV123@10fps and UAV20L fromthe unmanned air vehicle123(UAV123)dataset,show that SiamDPL can achieve superior performance and low complexity with a running speed of 100.1 fps on NVIDIA TITAN RTX.

Electronegativity-Induced Single-Ion Conducting Polymer Electrolyte for Solid-State Lithium Batteries

The application of solid polymer electrolytes(SPEs)is severely impeded by the insufficient ionic conductivity and low Li^(+)transference numbers(t_(Li)^(+)).Here,we report an iodine-driven strategy to address both the two longstanding issues of SPEs simultaneously.Electronegative lodine-containing groups introduced on polymer chains effectively attract Li^(+)ions,facilitate Li^(+)transport,and promote the dissociation of Li salts.Meanwhile,iodine is also favorable to alleviate the strong O-Li^(+)coordination through a Lewis acidbase interaction,further improving the ionic conductivity and t_(Li)^(+).As a proof of concept,an iodinated single-ion conducting polymer electrolyte(IPE)demonstrates a high ionic conductivity of 0.93 mS cm^(-1)and a high t_(Li)^(+)of 0.86 at 25℃,which is among the best results ever reported for SPEs.Moreover,symmetric Li/Li cells with IPE achieve a long-term stability over 2600 h through the in-situ formed LiF-rich interphase.As a result,Li-S battery with IPE maintains a high capacity of 623.7 mAh g^(-1)over 300 cycles with an average Coulombic efficiency of 99%.When matched with intercalation cathode chemistries,Li/IPE/LiFePO_(4)and Li/IPE/LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)solid-state batteries also deliver high-capacity retentions of 95%and 97%at 0.2 C after 120 cycles,respectively.

Progress and challenges of prelithiation technology for lithium-ion battery

Prelithiation technology is widely considered a feasible route to raise the energy density and elongate the cycle life of lithium-ion batteries.The principle of prelithiation is to introduce extra active Li ions in the battery so that the lithium loss during the first charge and long-term cycling can be compensated.Such an effect does not need to change the major electrode material or battery structure and is compatible with the majority of current lithium-ion battery production lines.At this stage,various prelithiation methods have been reported,some of which are already in the pilot-scale production stage.But there is still no definitive development roadmap for prelithiation.In this review,we first introduce the influence of prelithiation on electrochemical performance from a theoretical point of view and then compare the pros and cons of different prelithiation methods in different battery manufacturing stages.Finally,we discuss the challenges and future development trends of prelithiation.We aim to build up a bridge between academic research and industrial application.Some engineering problems in the promotion of prelithiation technique are extensively discussed,including not only the implementation of prelithiation but also some collateral issues on battery designing and management.

Facile synthesis of S-doped reduced TiO_(2-x) with enhanced visible-light photocatalytic performance

A different approach to synthesize visible‐light‐active sulfur(S)‐doped reduced titania(S‐TiO2‐x)using thiourea dioxide as both the S source and reductant was developed.The structure,morphology,and optical and electronic properties of the as‐prepared S‐TiO2‐x samples were examined by multiple techniques,such as X‐ray diffraction,transmission electron microscopy,X‐ray photoelectron spectroscopy,ultraviolet‐visible diffuse reflectance spectroscopy,Brunauer‐Emmett‐Teller and photocurrent measurements,and electrochemical impedance spectroscopy.The photocatalytic activity of S‐TiO2‐x was evaluated by photodegradation of organic Rhodamine B under visible‐light irradiation.The degradation rate of Rhodamine B by S‐TiO2‐x obtained by calcination was about31,2.5,and3.6times higher than those of pure TiO2,pristine TiO2‐x,and S‐doped TiO2,respectively.In addition,the as‐prepared S‐TiO2‐x exhibited long‐term stable photocatalytic performance in the degradation of Rhodamine B under visible‐light illumination.This report reveals a new approach to prepare stable and highly efficient solar light‐driven photocatalysts for water purification.

Preparation and characterization of octenyl succinic anhydride nano starch from tiger nut meals

Tiger nut(Cyperus esculentus L.)is an ideal raw material for oil extraction,but starch-rich tiger nut meal,a by-product of oil extraction,has not been fully utilized.For this,starch was isolated from tiger nut meal,and then starch nanoparticles were prepared by gelatinization,ultrasonication and nanoprecipitation under different conditions.The preparation parameters were optimized by measuring the particle size with dynamic light scattering,and the physicochemical properties of native starch and nano starch were evaluated.The results showed that,compared to native starch,starch nanoparticle(nano starch)has a higher amylose content(39.05%),solubility(56.13%),and swelling power(58.01%).Furthermore,native starch and nano starch were esterified with octenyl succinic anhydride(OSA),respectively,conferring amphiphilic properties.The effects of OSA modification on the resistant starch content,thermal properties,and microstructure of starches were characterized.The resistant starch content of tiger nut native starch increased by 10.81%after OSA modification,while the resistant starch content of OSA nano starch increased to 37.76%.Compared to native starch,the gelatinization temperature of OSA nano starch decreased by 2.7℃ and nano starch decreased by 5.68℃.OSA modified nano starch showed a unique microstructure,such as a slender fiber structure and a regular oblate structure.The hydrophobic OSA groups aggregated to form hydrophobic cavities with a hydrophilic surface in the aqueous phase.The findings presented in this investigation provide a better understanding of the design and development of OSA nano starch and provide valuable guidance to further enhance the added value of tiger nuts and future applications in the food industry.

Identification of two pIgR-like molecules in teleost fish with opposite roles in mucosal immunity against bacterial infection

Polymeric immunoglobulin(Ig)receptor-like(pIgRL)molecules have been identified in teleost fish.However,compared to functional studies of their related genes(e.g.,mammalian CD300 family)in eliminating pathogen invasion while preserving homeostasis,the roles of pIgRL in teleost fish remain unclear.In this study,we demonstrated that a pair of pIgRL molecules in zebrafish,pIgRL3.5 and pIgRL4.2,were highly expressed in the intestine and immune cells.Moreover,we constructed an Edwardsiella piscicida infection model,which induced strong inflammatory responses in the zebrafish intestine.Interestingly,pIgRL3.5 and pIgRL4.2 exhibited opposite inducible expression patterns in response to bacterial infection,suggesting that they perform different roles.More importantly,by conducting overexpression and knockdown experiments,our findings demonstrated that zebrafish pIgRL3.5 played a protective role in host defense against E.piscicida infection by inhibiting excessive inflammatory responses.In contrast,pIgRL4.2 facilitated pathogen growth and dissemination in zebrafish intestine.Collectively,our findings are the first to demonstrate that a pair of pIgRL molecules in teleost fish play opposite roles in mucosal immune response to bacterial infection.Therefore,our results provide crucial insights into the conserved role of pIgRL molecules in immune regulatory functions throughout vertebrate evolution.

质子交换膜燃料电池电流密度分布特性和研究展望

质子交换膜燃料电池具有无污染、噪声低、能量密度高、燃料转换效率高、响应速度快的显著优点,得到了迅速发展,但寿命仍然是制约其大规模商业化的重要原因。局部电流密度作为质子交换膜燃料电池运行过程中的重要参数,既能作为电池运行过程中的故障诊断和定位工具,提升电池运行的稳定性和和耐久性;又能提供电池运行期间其内部现象的有关信息,为深入理解电池反应机理以及优化电池设计提供有力指导,因此研究局部电流密度具有非常重要的意义。本文介绍并分析了实时原位测量局部电流密度的方法,比较了前人实验所得结果与模拟所得结果,阐述了相关参数对局部电流密度分布的影响机制,回顾并评析了局部电流密度用于燃料电池分析中的实际工作。最后,立足于局部电流密度的研究现状,给出了局部电流密度下一步的研究方向。

A simple daily dynamic feeding regimen for reducing phosphorus consumption and excretion in laying hens

Phosphorus metabolism in laying hens is a highly dynamic process over the course of the 24 h egg-laying cycle.Adjusting the phosphorus feeding regimen according to the daily egg-laying cycle may help to improve phosphorus utilization efficiency.Hy-Line Brown layers(n=120;70 wk old)were offered 4different phosphorus daily regimens:(1)RR,fed regular phosphorus at both 09:00 and 17:00;(2)RL,fed regular phosphorus at 09:00 and low phosphorus at 17:00;(3)LR,fed low phosphorus at 09:00 and regular phosphorus at 17:00;(4)LL,fed low phosphorus at both 09:00 and 17:00.The regular and low phosphorus diets contained 0.32% and 0.14% non-phytate phosphorus,respectively.The feeding trial lasted for 12 wk.As a result,layers on the RL regimen had decreased laying rate(P<0.05;5 to 8,9 to 12,and 1 to 12 wk)when compared to all other regimens.Layers on the LL regimen had decreased eggshell thickness and specific gravity(P<0.05;wk 8)when compared to all other regimens,and had decreased egg shell strength(P<0.05;wk 8)when compared to RL and LR regimens.When compared to the RR regimen(a common practice in the industry),layers on the LR regimen had:(1)identical laying performance and egg quality(P>0.05);(2)decreased phosphorus excretion(P<0.05)during the period of09:00 to 17:00;(3)increased jejunal calbindin D28k protein expression(P<0.05)2 h after feeding in the morning;(4)decreased serum fibroblast growth factor 23 and calcitriol levels(P<0.05),decreased jejunal type Ⅲ sodium-phosphate cotransporter 2 gene and protein expression(P<0.05),and decreased renal type Ⅲ sodium-phosphate cotransporter 1 protein expression(P<0.05),2 h after feeding in the afternoon.In summary,when dietary phosphorus was supplemented in accordance with daily serum phosphorus rhythms(i.e.,the LR regimen),laying performance and egg quality were well supported whilst significantly decreasing phosphorus consumption and excretion.Thus,serum phosphorus rhythms will need to be carefully maintained when developing dietary phosphorus-reduction strategies in laying hens.

The optimization of hydrothermal process of MoS2 nanosheets and their good microwave absorption performances

In this study,flower-like MoS2 constructed by nanosheets was synthesized by a simple hydrothermal method.The hydrothermal process was optimized and the effects of hydrothermal condition,including reaction temperature,reaction time and the ratio of Mo source to S source(Mo:S)in precursor,on microwave absorption performances and dielectric properties were investigated.Our results showed that when the reaction temperature was 180℃,the reaction time was 18 h,and the Mo:S was 1:3.5,the synthesized MoS2 had the best performance:Its minimum reflection loss could reach-55.78 dB,and the corresponding matching thickness was 2.30 mm with a wide effective bandwidth of 5.17 GHz.Further researches on the microwave absorption mechanism revealed that in addition to the destructive interference of electromagnetic waves,various polarization phenomena such as defect dipole polarization were the main reasons for microwave loss.We believe that MoS2 is a candidate for a practical microwave absorbent.

PARAMETRIC EQUATION SOLVING AND QUANTIFIER ELIMINATION IN FINITE FIELDS WITH THE CHARACTERISTIC SET METHOD

For a parametric algebraic system in finite fields, this paper presents a method for computing the cover and the refined cover based on the characteristic set method. From the cover, the author knows for what parametric values the system has solutions and at the same time presents the solutions in the form of proper chains. By the refined cover, the author gives a complete classification of the number of solutions for this system, that is, the author divides the parameter space into several disjoint components, and on every component the system has a fix number of solutions. Moreover, the author develops a method of quantifier elimination for first order formulas in finite fields.

An HPC Based Real-time Path Rating Calculation Tool for Congestion Management with High Penetration of Renewable Energy

Every year, transmission congestion costs billions ofdollars for electricity customers. This clearly identifies the criticalneed for more transmission capacity and also poses big challengesfor power grid reliability in stressed conditions due to heavyloading and in uncertain situations due to variable renewableresources and responsive smart loads. However, it becomesincreasingly difficult to build new transmission lines, whichtypically involve both economic and environmental constraints.In this paper, advanced computing techniques are developedto enable a non-wire solution that realizes unused transfercapabilities of existing transmission facilities. An integratedsoftware prototype powered by high-performance computing(HPC) is developed to calculate ratings of key transmission pathsin real time for relieving transmission congestion and facilitatingrenewable integration, while complying with the North AmericanElectric Reliability Corporation (NERC) standards on assessingtotal transfer capabilities. The innovative algorithms include: (1)massive contingency analysis enabled by dynamic load balancing,(2) parallel transient simulation to speed up single dynamicsimulation, (3) a non-iterative method for calculating voltagesecurity boundary and (4) an integrated package consideringall NERC required limits. This tool has been tested on realisticpower system models in the Western Interconnection of NorthAmerica and demonstrates satisfactory computational speedusing parallel computers. Various benefits of real-time path ratingare investigated at Bonneville Power Administration using realtime EMS snapshots, demonstrating a significant increase in pathlimits. These technologies would change the traditional goals ofpath rating studies, fundamentally transforming how the grid isoperated, and maximizing the utilization of national transmissionassets, as well as facilitating integration of renewable energy andsmart loads.

HVDC Macrogrid Modeling for Power-flow and Transient Stability Studies in North American Continental-level Interconnections

voltage direct current(HVDC)transmission lines are being constructed throughout the world,aided by advancements in power electronics and the potential value to transfer power between distant areas and off-shore locations.Multiple HVDC lines within and across large AC interconnections could bring about economic benefits such as interregional capacity exchange and transfer of low-cost,distant electric energy directly to load centers.In addition,network configuration of HVDC lines could result in additional benefits that have not been deeply studied.This paper describes the modeling process for continentallevel power system interconnections with the addition of multiple HVDC lines configured as a macrogrid.The models used for study are based on industry-accepted power-flow and dynamic system models for the North American Eastern and Western Interconnections.The model provides insight on feasibility and initial steady-state and stability tests of the HVDC macrogrid and its interactions with the existing electricity infrastructure,opening the door to analysis of the technical value of such a macrogrid.

Flow behavior of high-temperature flue gas in the heat transfer chamber of a pilot-scale coal-water slurry combustion furnace

The flow characteristics of high-temperature flue gas are important in the heat transfer of coal-water slurry（CWS） combustion furnaces.The flow field of a 250 kg/h vertical-type slag tap cyclone furnace was non-intrusively investigated,using two-dimensional particle-image velocimetry（2D PIV）.The method was verified using traceable fly ash particles in high-temperature flue gas.The flow field of the flue gas was analyzed with a time-averaged method,based on which the effects of excess air ratio and loading were investigated.The flue gas separated by a gas separator maintained good rigidity near the furnace wall,rather than eroding the heating surface.Numerical simulations validated the reliability of PIV under the actual circumstances within the furnace.This study provides guidelines for applying 2D PIV in analyzing flue gas in thermal test boilers.