检索结果-南通市图书馆

Prediction-based event-triggered identification of quantized input FIR systems with quantized output observations

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2020年第1期63卷 140-151页

作者： jin GUo jing-dong DIAo School of Automation and Electrical Engineering University of Science and Technology Beijing Key Laboratory.of Knowledge Automation for Industrial Processes Ministry of Education

This paper addresses the identification of finite impulse response(FIR) systems with both quantized and event-triggered observations. An event-triggered communication scheme for the binary-valued output quantization is introduced to save communication resources. Combining the empirical-measure-based identification technique and the weighted least-squares optimization, an algorithm is proposed to estimate the unknown parameter by full use of the received data and the not-triggered condition. Under quantized inputs, it is shown that the estimate can strongly converge to the real values and the estimator is asymptotically efficient in terms of the Cram′er-Rao lower bound. Further, the limit of the average communication rate is derived and the tradeoff between this limit and the estimation performance is discussed. Moreover, the case of multi-threshold quantized observations is considered. Numerical examples are included to illustrate the obtained main results.

关键词： identification FIR systems prediction-based event-triggered communication quantized observations convergence performance

A multifractal model for linking Lagrangian and Eulerian velocity structure functions

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2014年第4期30卷 480-484页

作者： yu-Feng dong Guo-dong jin LNM Institute of MechanicsChinese Academy of Sciences

A multifractal model is developed to connect the Lagrangian multifractal dimensions with their Eulerian counterparts. We propose that the characteristic time scale of a Lagrangian quantity should be the Lagrangian time scale, and it should not be the Eulerian time scale which was widely used in previous studies on Lagrangian statistics. Using the present model, we can obtain the scaling exponents of Lagrangian velocity structure functions from the existing data or models of scaling exponents of Eulerian velocity structure functions. This model is validated by comparing its prediction with the results of experiments, direct numerical simulations, and the previous theoretical models. The comparison shows that the proposed model can better predict the scaling exponents of Lagrangian velocity structure functions, especially for orders larger than 6.

关键词： Lagrangian multifractal - Eulerian multifractal -Intermittency . Velocity structure functions

Recent progress in reactivity study and synthetic application of N-heterocyclic phosphorus hydrides

在线全文

学校读者我要写书评

暂无评论

National Science Review 2021年第4期8卷 181-194页

作者： jingjing Zhang jin-dong yang jin-Pei Cheng Center of Basic Molecular Science Department of Chemistry Tsinghua University State Key Laboratory.of Elemento-organic Chemistry College of Chemistry Nankai University

N-heterocyclic phosphines(NHPs) have recently emerged as a new group of promising catalysts for metal-free reductions, owing to their unique hydridic reactivity. The excellent hydricity.of NHPs, which rivals or even exceeds those of many metal-based hydrides, is the result of hyperconjugative interactions between the lone-pair electrons on N atoms and the adjacent σ*(P–H) orbital. Compared with the conventional protic reactivity.of phosphines, this umpolung P–H reactivity leads to hydridic selectivity in NHP-mediated reductions. This reactivity has therefore found many applications in the catalytic reduction of polar unsaturated bonds and in the hydroboration of pyridines. This review summarizes recent progress in studies of the reactivity and synthetic applications of these phosphorus-based hydrides, with the aim of providing practical information to enable exploitation of their synthetically useful chemistry.

关键词： N-heterocyclic phosphine diazaphospholene hydride transfer metal-free reduction σ-bond metathesis

Classification of normal and abnormal ECG records using lead convolutional neural network and rule inference

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2017年第7期60卷 265-267页

作者： Linpeng jin Jun dong Suzhou Institute of Nano-tech and Nano-bionics Chinese Academy of Sciences University.of Chinese Academy.of Sciences

With the improvement of living standards,more and more people pay attention to their own health problems and performing an ECG test is the preferred selection for preventing cardiovascular *** it is easy to sample ECG now,diagnostic conclusion cannot be made because of the lack of domain experts,especially in the basic community medical insurance system(BCMIS)of China.A feasible solution is to send ECG records to a cloud-computing platform monitored by ECG

关键词： ECG Classification of normal and abnormal ECG records using lead convolutional neural network and rule inference RI NPV than

Lagrangian statistics in isotropic turbulent flows with deterministic and stochastic forcing schemes

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2015年第1期31卷 25-31页

作者： jin-Cai Chen Guo-dong jin Jian Zhang LNM Institute of MechanicsChinese Academy of Sciences

Artificial input of energy into the flow is neces sary to create and maintain a statistically stationary isotropic turbulence for sampling in studying the statistics. Due to the nonlinear coupling among different Fourier modes through the triadic interaction, whether or not various forc ing schemes affect the statistics in turbulence is an impor tant and open question. We present detailed comparison of Lagrangian statistics of fluids particles in forced isotropic turbulent flows in 1283, 2563, and 5123 simulations, with Tay.orscale Rey.olds numbers in the range of 64-171, us ing a deterministic and a stochastic forcing scheme, respec tively. Several Lagrangian statistics are compared, such as velocity and acceleration autocorrelations, and moments of Lagrangian velocity increments. The differences in the La grangian statistics obtained from the two forcing schemes are shown to be small, indicating that the isotropic forcing schemes used have little effects on the Lagrangian statistics in the isotropic turbulence.

关键词： Isotropic turbulence Deterministic forcingscheme Stochastic forcing scheme Lagrangian statisticalquantities

Morphology evolution of two-phase Cu-Ag alloys under different conditions

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第3期10卷 458-463页

作者： jin-li HU jin-dong ZHANG Liang MENG Department of Materials Science and Engineering Zhejiang University Hangzhou 310027 China Xingtai Xinhui Copper Special Wire. Co. Ltd. Xingtai 055550 China

Cu-Ag filamentary microcomposites with different Ag contents were prepared by cold drawing and intermediate heat treatments. The microstructure characterization and filamentary distribution were observed for two-phase alloys under different conditions. The effect of heavy drawing strain on the microstructure evolution of Cu-Ag alloys was investigated. The results show that the microstructure components consist of Cu dendrites, eutectic colonies and secondary Ag precipitates in the alloys containing 6%-24% （mass fraction） Ag. With the increase in Ag content, the eutectic colonies in the microstructure increase and gradually change into a continuous net-like distribution. The Cu dendrites, eutectic colonies and secondary Ag precipitates are elongated in an axial direction and developed into the composite filamentary structure during cold drawing deformation. The eutectic colonies tend to evolve into filamentary bundles. The filamentary diameters decrease with the increase in drawing strain degree for the two-phase alloys, in particular for the alloys with low Ag content. The reduction in filamentary diameters becomes slow once the drawing strain has exceeded a certain level.

关键词： Cu-Ag alloy Microstructure Strain Filamentary composite

EFFECTS oF LIQUID QUALITy.oN CAVITATIoN ERoSIoN

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 1992年第2期4卷 87-95页

作者： Zhang, dong jin, Tailai Water Conservancy and Hydroelectric Power Research Inst Beijing China

This paper is mainly devoted to conduct a series of vibratory cavitation erosion tests using the magnetostriction apparatus. Distilled water was used as a standard liquid medium for comparison and other liquids were glycerine, kerosene, silicone oil and water containing different concentration glycerine and solid particles, bakerite and fly ash. Experimental results indicate that viscosity.of liquid restrains, attenuates and alleviats cavitation erosion. Experiments witness that there exists critical concentration and equivalent concentration. The behaviour of cavitation clouds and the appearance of the pitting were observed. It is helpful to explain the effect of liquid quality.on cavitation erosion.

关键词： Cavitation Corrosion oil Magnetostriction

The texture and its optimization in magnesium alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第7期42卷 175-189页

作者： Jialin Wu Li jin Jie dong Fenghua Wang Shuai dong National Engineering Research Center of Light Alloy Net Forming Shanghai Jiao Tong UniversityShanghai 200240China

The crystallographic orientations are generally non-random in wrought Mg alloy,which will lead to their macroscopic physical properties to be *** the texture evolution in processing of Mg alloy billets and its effect on mechanical properties is therefore an important project for all scientists and engineers in material *** paper is concerned with the description of texture,with the mechanisms of texture evolution and with the interrelationships between texture and mechanical properties in Mg *** is a full review of understanding of the basic mechanism on texture evolution,of texture altering by alloying or processing,and of the mechanism of texture ***,it provides theories necessary and available techniques to develop high-performance Mg wrought with optimized texture in the field.

关键词： Magnesium alloy Texture Rare earth(RE) Anisotropic Mechanical property

Application of inverse method to estimation of boundary conditions during investment casting simulation

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2009年第6期22卷 429-434页

作者： Haipeng jin Jiarong LI dong PAN National Key Laboratory.of Advanced High Temperature Structural Materials Institute of AeronauticalMaterials Beijing 100095 China Key Lab for Advanced Materials Processing Technology MOE Department of Mechanical EngineeringTsinghua University Beijing 100084 China

Inverse method was used in single crystal superalloy DD6 processing simulation during solidification. Numerical modeling coupled with experiments has been used to estimate the interface heat transfer coefficient （IHTC） between the surface of slab casting and inner mold. Calculated temperature dependent values of IHTC were obtained from a numerical solution. The calculated temperatures agreed well with the measurement of cooling profile.

关键词： Numerical simulation Single crystal Inverse method Boundary conditions