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THE TYPE II DEFEcT IN 18R MARTENSITE IN A cu-Zn-Al AllOY

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Acta Metallurgica Sinica(English letters) 1998年第1期11卷 29-32页

作者： J.X.Zhang Y.F.Zheng W.cai l.c.zhao Harbin Inst of Technology Harbin China

Type H defect in 18R martensite in a cu-Zn-Al alloy has been studied by high resolution electron microscopy. It was found that Type H defect is not fault internal to martensite plate; rather,it is a stack of plates A and c. The rare observation of Type H defect is considered to be due to the fact that thc slice is too thin to exist for self-accommodation.

关键词： shape memory alloy cu-based alloy defect

Stress-Induced Martensitic Transformation of Zr_(50)cu_(25)Ni_(10)co_(15) Nanocrystals Embedded in an Amorphous Matrix

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Journal of Materials Science & Technology 2017年第3期33卷 276-280页

作者： W.H.Gao X.Y.Yi X.l.Meng G.Song W.cai l.c.zhao School of Materials Science and Engineering Harbin Institute of Technology Department of Mechanical Engineering University of Houston

The stress induced martensitic phase transformation of spherical Zrcu nanocrystals embedded in an amorphous matrix was studied in this paper. Microstructural observations revealed that the martensitic transformation of the nanocrystal was hindered by the surrounding amorphous coating. The existence of two-step transformation from the austenite phase（B2） to the base structure martensite（B19＇） and finally to the most stable superstructure martensite（cm） was also demonstrated. The cm martensite with（021） type I twinning symmetrically accommodation was surrounded by the B19＇ martensite with dislocation morphologies.

关键词： Nanocrystals Zrcu Martensitic phase transformation Shape memory Transmission electron microscopy

Gas-phase pressure and flow velocity fields inside a burning cigarette during a puff

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Gas-phase pressure and flow velocity fields inside a burning...

Adaptive neural network control of a 2-DOF helicopter system considering input constraints and global prescribed performance

中国烟草学会2017年学术年会

作者： B.li l.c.zhao l.Wang c.liu K.G.McAdam B.Wang Zhengzhou Tobacco Research Institute of cNTc

Heat and mass transfer inside a burning cigarette directly influence the level and chemical composition of its mainstream and sidestream emissions. During a 2-s 35 m l model puffing regime, different thermophysical processes occur inside the burning coal as a result of forced air flow, including rapid temperature rise up to 900?c and a series of pyrolytic or oxidative reactions leading to the formation of smoke aerosol. Accurate measurements of transient thermophysical parameters such as temperature,pressure and gas velocity are thus an essential step towards understanding the smoke formation. In this study, we have developed micro-sensors that can be accurately inserted at specific locations into a 3 R4 F research reference cigarette, and used to follow these sensitive and highly dynamic responses as a result of the puffing burn. Both temperature and pressure responses were systematically measured, and in combination with a computational method based on Darcy’s law, we obtained the gas flow velocity of the burning cigarette puffed under a standard machine-smoking protocol. These quantitative data provide unparalleled insights into the complex thermochemical processes responsible for smoke formation inside a burning cigarette.

关键词： cigarette Gas-phase Temperature Pressure Velocity Distribution

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Science china(Information Sciences) 2024年第7期67卷 224-239页

作者： Zhijia zhao Jiale WU Zhijie lIU We HE c.l.Philip cHEN School of Mechanical and Electrical Engineering Guangzhou University School of Intelligence Science and Technology and Key laboratory of Intelligent Bionic Unmanned Systems of Ministry of Education University of Science and Technology Beijing School of computer Science and Engineering South China University of Technology Pazhou lab

In this study, an adaptive neural network(NN) control is proposed for nonlinear two-degree-offreedom(2-DOF) helicopter systems considering the input constraints and global prescribed ***, radial basis function NN(RBFNN) is employed to estimate the unknown dynamics of the helicopter system. Second, a smooth nonaffine function is exploited to approximate and address nonlinear constraint functions. Subsequently, a new prescribed function is proposed, and an original constrained error is transformed into an equivalent unconstrained error using the error transformation and barrier function transformation methods. The analysis of the established lyapunov function proves that the controlled system is globally uniformly bounded. Finally, the simulation and experimental results on a constructed Quanser's test platform verify the rationality and feasibility of the proposed control.

关键词： adaptive NN control 2-DOF helicopter global prescribed performance input constraints

leveraging the potential of big genomic and phenotypic data for genome-wide association mapping in wheat

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The crop Journal 2024年第3期12卷 803-813页

作者： Moritz lell Yusheng zhao Jochen c.Reif leibniz Institute of Plant Genetics and crop Plant Research(IPK) Corrensstraße 3D-06466 SeelandGermany

Genome-wide association mapping studies(GWAS)based on Big Data are a potential approach to improve marker-assisted selection in plant *** number of available phenotypic and genomic data sets in which medium-sized populations of several hundred individuals have been studied is rapidly *** these data and using them in GWAS could increase both the power of QTl discovery and the accuracy of estimation of underlying genetic effects,but is hindered by data heterogeneity and lack of *** this study,we used genomic and phenotypic data sets,focusing on central European winter wheat populations evaluated for heading *** explored strategies for integrating these data and subsequently the resulting potential for *** interoperability between data sets was greatly aided by some overlapping genotypes and a linear relationship between the different phenotyping protocols,resulting in high quality integrated phenotypic *** this context,genomic prediction proved to be a suitable tool to study relevance of interactions between genotypes and experimental series,which was low in our *** to expectations,fewer associations between markers and traits were found in the larger combined data than in the individual experimental ***,the predictive power based on the marker-trait associations of the integrated data set was higher across data ***,the results show that the integration of medium-sized to Big Data is an approach to increase the power to detect QTl in *** results encourage further efforts to standardize and share data in the plant breeding community.

关键词： Big Data Genome-wide association study Data integration Genomic prediction Wheat

Robust Optimal Framework for Doubly Fed Induction Generator with Uncertain Dynamics

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Protection and control of Modern Power Systems 2024年第5期9卷 129-141页

作者： Yongfeng lü Xiaowei zhao Priyank Shah college of Electrical and Power Engineering Taiyuan University of TechnologyTaiyuan 030024China Intelligent control and Smart Energy(IcSE)Research Group School of EngineeringThe University of WarwickCoventry CV47ALUK

A robust optimal framework is designed herein to mitigate the oscillatory dynamics in a doubly fed induction generator(DFIG)even in the presence of network disturbances and input *** address uncertain dynamics,herein,a novel transformation formula is developed for a wind energy conversion *** unscented Kalman filter is applied to estimate the un-measured internal states of the wind energy conversion system using terminal *** detailed convergence and stability analyses of the presented framework are investigated to validate its ***,comparative modal analyses are carried out to demonstrate the improvement in the damping of critical low-frequency oscillatory modes using the presented *** simulation results demonstrate satisfactory performance under various operating scenarios,such as increasing and decreasing wind speed and varying the terminal *** comparative performance is demonstrated to validate the effectiveness of the presented framework over that of the state-of-the-art *** Terms—Optimal control,power system,renew-able energy sources,wind energy conversion system,doubly fed induction generator.

关键词： Optimal control power system renew-able energy sources wind energy conversion system doubly fed induction generator

Effects of layer interactions on instantaneous stability of finite Stokes flows

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 69-84页

作者： chen zhao Zhenli cHEN c.T.MUTASA Dong lI School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China

The stability analysis of a finite Stokes layer is of practical importance in flow control. In the present work, the instantaneous stability of a finite Stokes layer with layer interactions is studied via a linear stability analysis of the frozen phases of the base flow. The oscillations of two plates can have different velocity amplitudes, initial phases, and frequencies. The effects of the Stokes-layer interactions on the stability when two plates oscillate synchronously are analyzed. The growth rates of two most unstable modes when δ lmost equal, and δ = δ*/h*, where δ*and h*are the Stokes-layer thickness and the half height of the channel, respectively. However, their vorticities are different. The vorticity of the most unstable mode is symmetric, while the other is asymmetric. The Stokes-layer interactions have a destabilizing effect on the most unstable mode when δ lizing effect when δ > 0.68. However, the interactions always have a stabilizing effect on the other unstable mode. It is explained that one of the two unstable modes has much higher dissipation than the other one when the Stokes-layer interactions are strong. We also find that the stability of the Stokes layer is closely related to the inflectional points of the base-flow velocity profile. The effects of inconsistent velocity-amplitude, initial phase, and frequency of the oscillations on the stability are analyzed. The energy of the most unstable eigenvector is mainly distributed near the plate of higher velocity amplitude or higher oscillation frequency. The effects of the initial phase difference are complicated because the base-flow velocity is extremely sensitive to the initial phase.

关键词： finite Stokes layer instantaneous stability Stokes-layer interaction asynchronous oscillation

Data-driven Static Equivalence with Physics-informed Koopman Operators

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cSEE Journal of Power and Energy Systems 2024年第1期10卷 432-438页

作者： Wei lin changhong zhao Maosheng Gao c.Y.chung Department of Electrical Engineering The Hong Kong Polytechnic UniversityHong Kong SARChina Department of Information Engineering The Chinese University of Hong KongHong Kong SARChina School of Electrical Engineering Chongqing UniversityChongqing 400044China

With deployment of measurement units,fitting static equivalent models of distribution networks(DNs)by linear regression has been recognized as an effective method in power flow analysis of a transmission *** volatility of measurements caused by variable distributed renewable energy sources makes it more difficult to accurately fit such equivalent *** tackle this challenge,this letter proposes a novel data-driven method to improve equivalency accuracy of DNs with distributed energy *** letter provides a new perspective that an equivalent model can be regarded as a mapping from internal conditions and border voltages to border power *** mapping can be established through 1)Koopman operator theory,and 2)physical features of power flow equations at the root node of a *** of the proposed method is demonstrated on the IEEE 33-bus and IEEE 136-bus test systems connected to a 661-bus utility system.

关键词： Data-driven distribution network Koopman operator theory static equivalent model

Spatial distributions of soil nutrients affected by land use,topography and their interactions,in the loess Plateau of china

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International Soil and Water conservation Research 2024年第1期12卷 227-239页

作者： Wenxin Zhou changjia li Wenwu zhao lindsay c.Stringer Bojie Fu State Key laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijingChina Institute of land Surface System and Sustainable Development Faculty of Geographical ScienceBeijing Normal UniversityBeijingChina Department of Environment and Geography University of YorkYorkUK York Environmental Sustainability Institute University of YorkYorkUK

Soil nutrient availability and their spatial distributions are strongly related to land use and landscape *** study aims to address the knowledge gap regarding the interaction between these factors and the underlying *** selected five land uses(grassland with Artemisia gmelinii,woodland with Robinia pseudoacacia,shrubland with caragana korshinskii and Hippophae rhamnoides,and apple orchard with Malus pumila)and nine slope positions across hillslopes in the loess Plateau,china,to investigate their combined effects on the contents and stocks of soil organic carbon(SOc),total nitrogen(TN)and total phosphorus(TP).Parametric and non-parametric statistical tests were conducted to determine the significant differences in the means or the medians of the soil nutrient *** showed that the SOc and TN contents of shrubland with caragana korshinskii were statistically significantly greater than those of the grassland(pc and TN contents generally decreased from the upper slope to the middle slope,and to the foot slope for the grassland,woodland and shrublands,and on the contrary,an increasing trend from the upper slope,to the middle slope,and to the foot slope was identified for the apple *** study highlights that land use,slope position and their interaction have significant effects on the spatial distributions of soil *** provides essential empirical evidence for the identification of the optimal vegetation type and slope positions in land management and vegetation restoration activities.

关键词： Soil organic carbon Total nitrogen Total phosphorus Slope position Vegetation restoration