Wind Farm Coordinated Control for Power Optimization

以降低风电场尾流损失、优化风场出力为目标,设计基于Laguerre函数非线性预测控制（nonlinear modelpredictive control,NLMPC）方案的风场集群控制器。该控制器应用风场动态尾流模型,通过NLMPC统一调整风场内各机组转速以提升风场功率。在控制器设计中,使用有效风速预测误差校正对预测模型失配及超短期风速预测误差进行补偿,引入Laguerre函数降低滚动时域优化计算负担并分析了控制器对风速预测误差的鲁棒性能。仿真研究表明,集群控制器能够在不同风速条件下提升风场功率、降低优化计算负担,且对风速预测模型失配与风场自然风速预测误差具有鲁棒性。

Carbon-supported ultrafine Pt nanoparticles modified with trace amounts of cobalt as enhanced oxygen reduction reaction catalysts for proton exchange membrane fuel cells

To accelerate the kinetics of the oxygen reduction reaction(ORR)in proton exchange membrane fuel cells,ultrafine Pt nanoparticles modified with trace amounts of cobalt were fabricated and decorated on carbon black through a strategy involving modified glycol reduction and chemical etching.The obtained Pt36Co/C catalyst exhibits a much larger electrochemical surface area(ECSA)and an improved ORR electrocatalytic activity compared to commercial Pt/C.Moreover,an electrode prepared with Pt36Co/C was further evaluated under H2-air single cell test conditions,and exhibited a maximum specific power density of 10.27 W mgPt^-1,which is 1.61 times higher than that of a conventional Pt/C electrode and also competitive with most state-of-the-art Pt-based architectures.In addition,the changes in ECSA,power density,and reacting resistance during the accelerated degradation process further demonstrate the enhanced durability of the Pt36Co/C electrode.The superior performance observed in this work can be attributed to the synergy between the ultrasmall size and homogeneous distribution of catalyst nanoparticles,bimetallic ligand and electronic effects,and the dissolution of unstable Co with the rearrangement of surface structure brought about by acid etching.Furthermore,the accessible raw materials and simplified operating procedures involved in the fabrication process would result in great cost-effectiveness for practical applications of PEMFCs.

Multifunctional binder designs for lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries are promising next-generation high energy density batteries but their practical application is hindered by several key problems,such as the intermediate polysulfide shuttling and the electrode degradation caused by the sulfur volume changes.Binder acts as one of the most essential components to build the electrodes of Li-S batteries,playing vital roles in improving the performance and maintaining the integrity of the cathode structure during cycling,especially those with high sulfur loadings.To date,tremendous efforts have been devoted to improving the properties of binders,in terms of the viscosity,elasticity,stability,toughness and conductivity,by optimizing the composition and structure of polymer binders.Moreover,the binder modification endows them strong polysulfide trapping ability to suppress the shuttling and decreases the swelling to maintain the porous structure of cathode.In this review,we summarize the recent progress on the binders for Li-S batteries and discuss the various routes,including the binder combination use,functionalization,in-situ polymerization and ion cross-linking,etc.,to enhance their performance in stabilizing the cathode,building the high sulfur loading electrode and improving the cyclic stability.At last,the design principles and the problems in further applications are also highlighted.

Hollow carbon microbox from acetylacetone as anode material for sodium-ion batteries

Carbon-based materials have attracted much interest as one of the promising anodes for sodium-ion batteries. However, low utilization of electrolyte and slow ion-transfer rate during electrochemical process hinder the further application of traditional bulk carbon. In order to enhance the diffusion kinetics and maintain the reversibility, hierarchical hollow carbon microbox was successfully prepared through a tunable bottom-up self-template routine for sodium-ion batteries. During annealing process, the morphology construction and activation happened synchronously. Based on that, a range of cross-linked porous nanosheet and hollow microbox were attained by manipulating reactant condition. The generation of texture and physical property are analyzed and are established linkages related to the electrochemical behavior. As results depicted in kinetic exploration and simulation based on cyclic voltammetry, the surfacecontrolled electrochemical behavior gradually turns to be the diffusion-controlled behavior as the hollow microbox evolves to porous nanosheet. The probable reason is that the rational microstructure/texture design leads to the accelerated diffusion kinetic procedure and the reduced concentration difference polarization. Sodium storage mechanism was deduced as reversible binding of Na-ions with local defects,including vacancies on sp2 graphitic layers, at the edges of flakes and other structural defects instead of intercalation. Bestowed by the morphology design, the broad pore width distribution, abundant defects/active sites and surface functionality, hollow microbox electrode delivers great electrochemical performances. This work is expected to propose a novel and effective strategy to prepare tunable hierarchical hollow carbon microbox and induce the fast kinetic of carbon anode material.

A Paleoproterozoic(Orosirian) Ophiolitic Mélange, North Yangzte Craton

Ophiolites represent fragments of ancient oceanic lithosphere,tectonically incorporated into continental margins during plate subduction or remained in the subduction–collisional orogenic belt.They provide

THE EVALUATION, DATA FUSION AND APPLICATION OF FY2E SST IN TROPICAL CYCLONES OVER NORTHWEST PACIFIC OCEAN

The daily FY2 E Sea Surface Temperature(SST) data from China National Satellite Meteorological Center(NSMC) was evaluated and compared with the Optimum Interpolation Sea Surface Temperature(OISST) data from US National Oceanic and Atmospheric Administration(NOAA) over Northwest Pacific Ocean(NPO) in this study. The results show that the distribution of FY2 E SST is close to OISST in tropical region over NPO, especially in typhoon active season, but the value of FY2 E SST is a little lower than that of OISST in tropical ocean, with the absolute deviation 1℃ lower and the relative deviation about 6% lower. The correlation coefficient between monthly FY2 E SST and monthly OISST is as high as 0.7, which passes the t-test at a significance level of 0.01. Based on the evaluation result, the merged SST_(FY)over NPO is calculated using a weighting function. Besides, Tropical Cyclone Heat Potential(TCHP_(FY)) is calculated and combined with the simulated sea temperature profile. From three years operational tests in NSMC, the merged SST_(FY)and TCHP_(FY)are shown to be good indexes in monitoring and predicting the intensity of tropical cyclones(TCs) over NPO.

Diffusion Coefficients of L-Arginine in Non-Newtonian Fluid

L-Arginine is an important component of amino acid injection. Its diffusion in body fluid and blood is of key importance to understand drug diffusion and drug release. As a fundamental demand for study and being a considerably valuable reference for application, in this study, the diffusion coefficients of L-arginine in polyacrylamide（PAM） aqueous solution used as non-Newtonian fluid similar to blood and body fluid were measured using a holographic interferometer. The effects of interaction among molecules and solution concentration on diffusion were analyzed and discussed, respectively. Based on the obstruction-scaling model, a novel modified model was presented for predicting diffusivity of solute in non-Newtonian fluid. Good agreement was achieved between the calculated value and the experimental data.

Acetone Formation from Photolysis of 2-Propanol on Anatase-TiO2（101）

Photocatalysis of 2-propanol on A-TiO2（101） has been investigated using a temperature programed desorption method with 266 nm laser light. A clear mechanism is proposed for photodissociation of 2-propanol on A-TiO2（101）. Acetone product on five coordinate Ti4＋ sites is formed in a stepwise manner in which the O-H dissociation proceeds first and then followed by secondary C-H dissociation of 2-propanol while H atoms are transferred to the adjacent bridge bond oxygen （BBO） sites. Low temperature water is formed in a thermally driven process via H-atom on BBO in exchange with isopropyl groups of molecule 2-propanol, while isopropyl radical desorbs at high temperature during the TPD process. The observation demonstrates the prospect of TiO2 as a photocatalyst for degradation of organics.

Phase-field simulation of dendritic sidebranching induced by thermal noise

The influence of undercooling and noise magnitude on dendritic sidebranching during crystal growth was investigated by simulation of a phase-field model which incorporates thermal noise. It is shown that, the sidebranching is not influenced with inclusion of the nonconserved noise, therefore, in order to save the computational costs it is often neglected; while conserved noise drives the morphological instability and is dominant origin of sidebranching. The dependence of temperature field on magnitude of thermal noise is apparent, when F_u gets an appropriate value, noise can induce sidebranching but not influence the dendritic tip operating state. In the small undercooled melt, the thermal diffusion layer collected around the dendrite is thick, which suppresses the growth of its sidebranching and makes the dendrite take on the morphology of no sidebranching, but when the undercooling is great, the thermal diffusion layer is thin, which is advantageous to the growth of the sidebranching and the dendrite presents the morphology of the developed sidebranching.

Seismic damage-cracking analysis of arch dams using different earthquake input mechanisms

In this study, a nonlinear model is presented for analysis of damage-cracking behavior in arch dams during strong earthquakes using different seismic input mechanisms. The nonlinear system includes a plastic-damage model for cyclic loading of concrete considering strain softening and a contact boundary model of contraction joint opening. Two different earthquake input mechanisms are used for comparison, including massless foundation input model and viscous-spring boundary model considering radiation damping due to infinite canyon. The results demonstrate that effects of seismic input mechanism and radiation damping on nonlinear response and damage-cracking of the dam are significant. Compared with the results of using massless foundation input model, the damage-cracking region and contraction joint opening are substantially reduced when using viscous-spring boundary model to take into account radiation damping. However, if the damping ratio of the dam is artificially increased to about 10%―15% for massless foundation input model, the joint opening and damage-cracking of the dam are comparable to the results obtained from the viscous-spring boundary model.

An amplification-selection model for quantified rhizosphere microbiota assembly

National Key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences;Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University;University of Chinese Academy of Sciences;Center for Multi-Omics Research, Collaborative Innovation Center of Crop Stress Biology, Henan Province, Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University.

Nonlinear quantum interferometry with Bose condensed atoms

In quantum interferometry, it is vital to control and utilize nonlinear interactions for the achievement of high-precision measurements. Due to their long coherence time and high controllability, ultracold atoms including Bose condensed atoms have been widely used for quantum interferometry. Here, we review recent progress in theoretical studies of quantum interferometry with Bose condensed atoms. In particular, we focus on nonlinear phenomena induced by atom-atom interactions, and how to control and utilize these nonlinear phenomena. With a mean-field description, due to atom-atom interactions, matter-wave solitons appear in the interference patterns, and macroscopic quantum self-trapping exists in Bose-Josephson junctions. With a many-body description, atom-atom in- teractions can generate non-classical entanglement, which can be utilized to achieve high-precision measurements beyond the standard quantum limit.

The new era for organic solar cells: polymer acceptors

Organic solar cells(OSCs)have made fast advance with prominent power conversion efficiencies(PCEs)achieved in non-fullerene OSCs in recent years[1].Among various types of OSCs,allpolymer solar cells(APSCs)consisting of a polymer donor and a polymer acceptor are promising power sources for portable and wearable electronics due to their intrinsic advantages in device stability and mechanical flexibility[2].

Classification of Sandstone-Related Uranium Deposits

Sandstone type deposits are the most common type of uranium deposits in the world.A large variety of sub-types have been defined,based either on the morphology of the deposits(e.g.,tabular,roll front,etc),or on the sedimentological setting(e.g.,paleovalley,paleochannel,unconformity),or on tectonic or lithologic controls(e.g.,tectonolithologic,mafic dykes/sills),or still on a variety of others characteristics(phreatic oxidation type,interlayer permeable type,multi-element stratabound infiltrational,solution front limb deposit,humate type,etc.),reflecting the diversity of the characteristics of these deposits,but making it difficult to have a clear overview of these deposits.Moreover,uranium deposits occurring in the same sedimentological setting(e.g.,paleochannel),presenting similar morphologies(e.g.,tabular),may result from different genetic mechanisms and thus can be misleading for exploration strategies.The aim of the present paper is to propose a new view on sandstone-related uranium deposits combining both genetic and descriptive criteria.The dual view is indeed of primordial importance because all the critical characteristics of each deposit type,not limited to the morphology/geometry of the ore bodies and their relationships with depositional environments of the sandstone,have to be taken into account to propose a comprehensive classification of uranium deposits.In this respect,several key ore-forming processes,like the physical-chemical characteristics of the mineralizing fluid,have to be used to integrate genetic aspects in the classification.Although a succession of concentration steps,potentially temporally-disconnected,are involved in the genesis of some uranium mineralization,the classification here proposed will focus on the main mechanisms responsible for the formation and/or the location of ore deposits.The objective of this paper is also to propose a robust and widely usable terminology to define and categorize sandstone uranium deposits,considering the diversity of their origin and morphologies,and will be primarily based on the temperature of the mineralizing fluid considered as having played the critical role in the transportation of the uranium,starting from synsedimentary uranium deposits to those related to higher temperature fluids.

A vicinal effect for promoting catalysis of Pd1/TiO2:supports of atomically dispersed catalysts play more roles than simply serving as ligands

Atomically dispersing metal atoms on supports has been emerging as an effective strategy to maximize the atom utilization of metals for catalysis. However, due to the lack of effective tools to characterize the detailed structure of metal-support interface, the chemical functions of supports in atomically dispersed metal catalysts are hardly elucidated at the molecular level. In this work, an atomically dispersed Pdl/ Ti02 catalyst with Ti（III） vicinal to Pd is prepared and used to demonstrate the direct involvement of metal atoms on support in the catalysis of dispersed metal atoms. Systematic studies reveal that the Ti （IlI）-O-Pd interface facilitates the activation of 02 into superoxide （02）, thus promoting the catalytic oxi- dation. The catalyst exhibits the highest CO turn-over frequency among ever-reported Pd-based catalysts, and enhanced catalysis in the combustion of harmful volatile organic compound （i.e., toluene） and green- house gas （i.e., methane）. The demonstrated direct involvement of metal atoms on oxide support suggests that the real active sites of atomically dispersed metal catalysts can be far beyond isolated metal atoms themselves. Metal atoms on oxide supports in the vicinity serve as another vector to promote the catalysis of atomically dispersed metal catalysts.

Hollow CdS-based photocatalysts

In recent years,photocatalytic technology,driven by solar energy,has been extensively investigated to ease energy crisis and environmental pollution.Nevertheless,efficiency and stability of photocatalysts are still unsatisfactory.To address these issues,design of advanced photocatalysts is important.Cadmium sulphide(CdS)nanomaterials are one of the promising photocatalysts.Among them,hollow-structured CdS,featured with enhanced light absorption ability,large surface area,abundant active sites for redox reactions,and reduced diffusion distance of photogenerated carriers,reveals a broad application prospect.Herein,main synthetic strategies and formation mechanism of hollow CdS photocatalysts are summarized.Besides,we comprehensively discuss the current development of hollow-structured CdS nanomaterials in photocatalytic applications,including H2 production,CO2 reduction and pollutant degradation.Finally,brief conclusions and perspectives on the challenges and future directions for hollow CdS photocatalysts are proposed.

Progress in the beam commissioning of separated function RFQ accelerator

Separated Function RFQ (SFRFQ) was proposed as a post accelerator of RFQ to accelerate heavy ions at low frequency. It introduces gap accelerating in the quadrupole electrodes, and therefore it has higher accelerating efficiency than the conventional RFQ accelerator. The first SFRFQ prototype cavity has been specially designed and constructed as a post accelerator to accelerate O+ beam from 1.03 MeV to 1.64 MeV. Based on accomplishment of low power measurement and high power test, the beam commissioning was carried out to verify its feasibility. The measured energy gain per cell of SFRFQ is 45 keV, which is about 60% higher than that of Peking University Integral Split Ring (ISR) RFQ.

The circadian clock ticks in plant stress responses

The circadian clock,a time-keeping mechanism,drives nearly 24-h self-sustaining rhythms at the physiological,cellular,and molecular levels,keeping them synchronized with the cyclic changes of environmental signals.The plant clock is sensitive to external and internal stress signals that act as timing cues to influence the circadian rhythms through input pathways of the circadian clock system.In order to cope with environmental stresses,many core oscillators are involved in defense while maintaining daily growth in various ways.Recent studies have shown that a hierarchical multi-oscillator network orchestrates the defense through rhythmic accumulation of gene transcripts,alternative splicing of mRNA precursors,modification and turnover of proteins,subcellular localization,stimuli-induced phase separation,and long-distance transport of proteins.This review summarizes the essential role of circadian core oscillators in response to stresses in Arabidopsis thaliana and crops,including daily and seasonal abiotic stresses(low or high temperature,drought,high salinity,and nutrition deficiency)and biotic stresses(pathogens and herbivorous insects).By integrating time-keeping mechanisms,circadian rhythms and stress resistance,we provide a temporal perspective for scientists to better understand plant environmental adaptation and breed high-quality crop germplasm for agricultural production.

Improved Mesenchymal Stem Cell Survival in Ischemic Heart through Electroacupuncture＊

Objective： To investigate whether electroacupuncture （EA） can promote cell survival and enhance heart function of mesenchymal stem cells （MSCs） therapy. Methods： MSCs were isolated from bone marrow and expanded in Minimum Essential Medium Alpha （α-MEM）. MI was induced in 72 Sprague-Dawley （S-D） rats by ligation of the left anterior descending coronary artery （LAD） for 30 min and reperfusion. MI rats randomly received injection of 1 x 106 Dil-labeled MSCs alone （n=24, MSC group）, or plus electroacupuncture （EA） at Neiguan （PC6, n=24, EA＋MSC group）, or saline （n=24, saline group）. EA treatment was performed for 4 days. Another 24 rats were subjected to chest-open surgery without LAD occlusion and treatment （sham group）. Three time points, 4, 14 and 28 days （n=8 for each group） were included in this study. The survival of transplanted MSCs and the protective gene expression were analyzed by reverse transcriptase polymerase chain reaction （RT-PCR） and Western blot at day 4 and 14. Left ventricular remodeling, cardiac function, infarction area, fibrosis and capillary density were analyzed at day 28. Results： EA can enhance MSC survival （2.6-fold up） at day 4. Big capillary density was 53% higher in EA＋MSC treated group than MSC alone group. Furthermore, the rats treated by EA reduced the fibrosis and had 36% smaller infarct size comparing to MSC alone. EA also attenuated left ventricular remodeling and enhanced the functional recovery of infarcted hearts at week 4. Conclmion： EA at Neiguan acupoint can promote the stem cell survival and improve ischemic heart function. EA could become a useful approach in stem cell therapy for ischemia heart diseases.