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Air concentration distribution in the impact zone of spillway aerator

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Journal of Hydrodynamics 2022年第1期34卷 156-161页

作者： Rui-di Bai fa-xing zhang Wei Wang Shan-jun Liu State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China

The chute aerators separate the flow from the chute bottom,and the violent turbulence is generated after the flow impacts the *** the chute aerators were widely investigated experimentally,the air concentration distribution of the lower jet in the impact zone remains to be explored *** the impact zone,it is observed that a portion of the air stays in the rollers instead of traveling with the flow,decreasing the air transportation *** on extensive tests,a comprehensive formula is developed to compute the air concentration distribution in the impact zone,with results in good agreement with the model tests.

关键词： Chute aerator impact zone air concentration cavity length experimental data

Air entrainment and detrainment downstream a chute aerator

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Journal of Hydrodynamics 2019年第1期31卷 76-82页

作者： Rui-di Bai fa-xing zhang Wei Wang Shan-jun Liu State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China

The chute aerators separate the flow from the chute bottom,and the air can enter into the flow through the lower *** this study,the air concentration and the pressure along the chute bottom are investigated systematically by a series of model tests with the upper aeration effect being *** chute downstream the aerator is partitioned into four zones:the cavity zone,the impact zone,the equilibrium zone,and the far *** is found that a large amount of air entrained in the cavity zone is only partially entrained into the flow ***,the lower air discharge is decreased sharply in the impact zone,and the detrainment disappearsonthe section of x= *** the equilibrium zone,the lower air discharge is kept *** the in crease of the flow Froude number and withthe other parameters kept unchanged,it is found that the dimensionless value of K has a significant ***,a formula to calculate K is proposed,with results in good agreement with the model and prototype data.

关键词： Chute aerator air concentration entrainment detrainment

A factor-GARCH Model for High Dimensional Volatilities

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Acta Mathematicae Applicatae Sinica 2022年第3期38卷 635-663页

作者： Xiao-ling LI Yuan LI Jia-zhu PAN xing-fa zhang School of Economics and Statistics Guangzhou UnversityGuangzhou 510006China College of Mathematics and Informatics South China Agricultural UniversityGuangzhou 510642China Department of Mathematics&Statistics University of StrathclydeGlasgow G11XHUK

This paper proposes a method for modelling volatilities(conditional covariance matrices)of high dimensional dynamic *** combine the ideas of approximate factor models for dimension reduction and multivariate GARCH models to establish a model to describe the dynamics of high dimensional *** condition and thresholding technique are applied to the estimation of the error covariance matrices,and quasi maximum likelihood estimation(QMLE)method is used to estimate the parameters of the common factor conditional covariance *** theories are developed for the proposed *** Carlo simulation studies and real data examples are presented to support the methodology.

关键词： approximate factor models conditional variance-covariance matrix multivariate GARCH sparse estimation thresholding

Experimental study of air-water interface properties in self-aerated flows

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Journal of Hydrodynamics 2019年第5期31卷 940-948页

作者： Wang-ru Wei Wei-lin Xu Jun Deng Zhong Tian fa-xing zhang State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China

The microscopic air-water structures and the interface area properties in the self-aerated flows are important research issues in the high-speed self-aerated *** present experimental study concerns the mean and medium air chord length distributions in the self-aerated chute flows for different flow Reynolds numbers and air concentration *** relationship between the microscopic and the macroscopic aerated properties in the air-water mixture region is *** distribution of the microscopic specific air-water interface area with the macroscopic air concentration variation is self-similar in the self-aerated *** view of the difference of the air-water structure in high and low aerated regions,a new relationship is proposed for predicting the distributions of a specific air-water interface area,and the agreement between the measured and predicted results is satisfactory.

关键词： Air-water interface area self-aeration air chord size chute flow experimental study

Alterations to biological soil crusts with alpine meadow retrogressive succession affect seeds germination of three plant species

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Journal of Mountain Science 2016年第11期13卷 1995-2005页

作者： LI Yi-kang OUYANG Jing-zheng LIN Li XU xing-liang zhang fa-wei DU Yan-gong LIU Shu-li CAO Guang-min HAN fa Key Laboratory of Adaptation and Evolution of Plateau Biota Northwest Institute of Plateau BiologyChinese Academy of SciencesXining 810001China University of Chinese Academy of Sciences Beijing 100049China Institute of Geographic Sciences&Natural Resources Research the Chinese Academy of SciencesBeijing 100101China Liancheng National Nature Reserve of Gansu Province Yongdeng Country 730000China

Biological soil crusts(BSCs) are the important components of alpine meadow *** extent and morphology of BSCs vary greatly with alpine meadow retrogressive succession due to grazing *** is significant interest in impacts of crust composition on plant seed germination,especial l y in(semi-) arid ***,little is known about the influences of BSCs,and their associations with alpine meadow succession,on germination of typical alpine meadow vascular plant *** a full factorial common-gardenexperiment,we studied effects of:(1) crust type,(2) seed position,and(3) surface texture on seed *** chose three typical alpine meadow plant species(*** pratensis,Tibetia himalaica and Potentillen nivea),which belonged to different functional groups(graminoids,legumes,and forbs) and play important roles in all alpine meadow succession *** type and seed position influenced seed germination,and the inhibitory effects of BSCs depended on the crust type and seed species *** major factors influencing seed germination were BSC type,seed position,soil texture,and the interactions between BSC type and seed position; species and seed position; species andsurface texture; and species,crust type,and surface *** crust significantly inhibited germination of all *** position also had a significant effect on seed germination(p face than below the surface,this was especially true for *** within cyanobacteria and lichen *** germination rates of *** on the soil surface were significantly correlated with plant occurrence frequency within the alpine meadow *** poor correlation for the other two species is possibly that they are *** results clearly demonstrated that BSCs can be biological filters during seed germination,depending on the BSC succession *** their influences on seed germination,BSCs can strongly

关键词： Crust type Seed position Microenvironment Germination Tibetan Plateau Vascular plants

A Major QTL, Ghd8, Plays Pleiotropic Roles in Regulating Grain Productivity, Plant Height, and Heading Date in Rice

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Molecular Plant 2011年第2期4卷 319-330页

作者： Wen-Hao Yan Peng Wang Hua-Xia Chen Hong-Ju Zhou Qiu-Ping Li Chong-Rong Wang Ze-Hong Ding Yu-Shan zhang Si-Bin Yu Yong-Zhong xing Qi-fa zhang National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan) Huazhong Agricultural University Wuhan430070 China

Rice yield and heading date are two distinct traits controlled by quantitative trait loci （QTLs）. The dissection of molecular mechanisms underlying rice yield traits is important for developing high-yielding rice varieties. Here, we report the cloning and characterization of Ghd8, a major QTL with pleiotropic effects on grain yield, heading date, and plant height. Two sets of near isogenic line populations were developed for the cloning of GhdS. Ghd8 was narrowed down to a 20-kb region containing two putative genes, of which one encodes the OsHAP3 subunit of a CCAAT-box binding protein （HAP complex）; this gene was regarded as the Ghd8 candidate. A complementary test confirmed the identity and pleiotropic effects of the gene; interestingly, the genetic effect of Ghd8 was dependent on its genetic background. By regulating Ehdl, RFT1, and Hd3a, Ghd8 delayed flowering under long-day conditions, but promoted flowering under short-day conditions. Ghd8 up-regulated MOC1, a key gene controlling tillering and branching; this increased the number of tillers, primary and secondary branches, thus producing 50% more grains per plant. The ectopic expression of Ghd8 in Arabidopsis caused early flowering by 10 d-a situation similar to the one observed by its homolog AtHAP3b, when compared to wild-type under long-day conditions; these findings indicate the conserved function of Ghd8 and AtHAP3b in flowering in Arabidopsis. Our results demonstrated the important roles of Ghd8 in rice yield formation and flowering, as well as its opposite functions in flowering between rice and Arabidopsis under long-day conditions.

关键词： Near isogenic lines CCAAT-box binding protein ectopic expression flowering pathway yield formation

Effect of jet milling on micro-strain behavior and rupture behavior of agglomerates of ultrafine WC powders

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Transactions of Nonferrous Metals Society of China 2019年第10期29卷 2128-2140页

作者： Ya-li SUN Qing-cai LIU Xin HUANG fa-xing zhang Jian YANG Hua MEI College of Materials Science and Engineering Chongqing UniversityChongqing 400044China College of Materials Science and Engineering Sichuan University of Science and EngineeringZigong 643000China College of Chemical Engineering Sichuan University of Science and EngineeringZigong 643000China Zhuzhou Cemented Carbide Cutting Tools Co. Ltd.Zhuzhou 412007China

The Williamson-Hall and uniaxial compression methods were used to study the variations of the micro-strain and stress-strain relations in WC powders after jet milling and ball milling, respectively. The rupture behavior of agglomerates in WC powders was investigated. Meanwhile, the as-obtained WC powders treated by different milling methods were used to fabricate WC-10%Co cemented carbides, followed by the performance assessment of cemented carbides. The results show that the micro-strain of the jet-milled WC powders decreases significantly compared with that of the ball-milled WC powders, and that the cemented carbides prepared by jet-milled WC powders exhibit excellent properties with a transverse-rupture strength of 4260 MPa, due to the elimination of agglomerates and the reduction of lattice strain.

关键词： ultrafine WC powder micro-strain stress-strain relation jet milling agglomerate rupture mechanism

Distributed optimal consensus control for multiagent systems based on event-triggered and prioritized experience replay strategies

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Science China(Information Sciences) 2025年第1期68卷 306-321页

作者： Cuijuan zhang Lianghao JI Shasha YANG xing GUO Huaqing LI Chongqing Key Laboratory of Image Cognition Chongqing University of Posts and Telecommunications Key Laboratory of Intelligent Perception and Computing of Anhui Province Anqing Normal University College of Electronic and Information Engineering Southwest University

This study uses event-triggered(ET) and reinforcement learning methods to investigate the optimal consensus control problem for cooperative-competitive multiagent systems. It proposes a novel distributed ET control strategy, which relies on a prioritized experience replay(PER) policy. This strategy not only conserves communication resources but also ensures acceptable system performance. To implement the proposed method, actor-critic(AC) dual-structured neural networks(NNs) are used to approximate the value function and control policy. In the AC NNs, the weight estimates for the NNs are updated at the moment of event triggering, resulting in a nonperiodic weight adjustment pattern. This approach decreases the computational cost in comparison with the traditional ET mechanism. The PER-based ET mechanism makes full use of valid historical data and effectively establishes a balance between system performance and communication resource ***, it does not require the following two conditions in most existing studies:(1) requirement of the system dynamics model to be known, and(2) persistent excitation. In addition, Zeno behavior is excluded from this study. Finally, a simulation is conducted to confirm the validity of the suggested approach.

关键词： multiagent systems event-triggered mechanism prioritized experience replay dual-structured neural networks optimal consensus control

Graphene Aerogel Composites with Self‑Organized Nanowires‑Packed Honeycomb Structure for Highly Efficient Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第2期17卷 533-547页

作者： Xiao You Huiying Ouyang Ruixiang Deng Qiuqi zhang Zhenzhong xing Xiaowu Chen Qingliang Shan Jinshan Yang Shaoming Dong State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China Key Laboratory of Inorganic Coating Materials CAS Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China Structural Ceramics and Composites Engineering Research Center Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049People’s Republic of China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210People’s Republic of China School of Materials Science and Engineering Zhejiang Sci-Tech UniversityHangzhou 310018People’s Republic of China University of Chinese Academy of Sciences Beijing 100039People’s Republic of China

With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave ***,a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss *** macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires(SiC_(nws))grown in situ,while boron nitride(BN)interfacial structure is introduced on graphene *** unique composite structure forces multiple scattering of incident EMWs,ensuring the combined effects of interfacial polarization,conduction networks,and magnetic-dielectric ***,the as-prepared composites present a minimum reflection loss value of−37.8 dB and a wide effective absorption bandwidth(EAB)of 9.2 GHz(from 8.8 to 18.0 GHz)at 2.5 ***,relying on the intrinsic high-temperature resistance of SiC_(nws) and BN,the EAB also remains above 5.0 GHz after annealing in air environment at 600℃ for 10 h.

关键词： Hierarchical porous structure Interface High-temperature resistance Graphene aerogel composites Electromagnetic wave absorption