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New method for the preparation of semi-solid AlSi7Mg alloy slurry

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Journal of University of Science and Technology Beijing 2007年第1期14卷 56-60页

作者： Weimin mao hai Lin Yuelong Bai Songfu Gao Materials Science and Engineering School University of Science and Technology Beijing Beijing 100083 China

The effects of pouring temperature and short electromagnetic stirring with low strength on the microstructures of AlSi7Mg alloy were investigated. The results show that if liquid AlSi7Mg alloy is poured at 630 or 650℃, many primary α-Al grains in the solidified melt are rosette-like, and only a small number of them are spherical. However, if liquid AlSi7Mg alloy is poured at a lower superheat and meanwhile is stirred by an electromagnetic field at a low power for a short time, then most primary α-Al grains in the solidified melt become spherical, and only a few are rosette-like. The theoretical analysis indicates that the strengthened melt flow motion induced by the short electromagnetic stirring makes the temperature field more homogeneous in the melt, which is poured at a lower superheat, and makes the primary α-Al grains deposit in a larger region at the same time, so this new solidification kinetic condition leads to the microstructure of spherical primary α-Al grains. The experiments also demonstrate that pouring at an appropriate superheat and stirring by an electromagnetic field at a low power for a short time is a good new method for preparing the semi-solid slurry or billet of AlSi7Mg alloy.

关键词： AlSi7Mg alloy semi-solid pouring temperature electromagnetic stirring

Robust fault-tolerant attitude control for satellite with multiple uncertainties and actuator faults

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Chinese Journal of Aeronautics 2020年第12期33卷 3380-3394页

作者： Liming FAN hai huang Kaixing ZHOU School of Astronautics Beihang UniversityBeijing 102206China Beijing Institute of Electronic System Engineering Beijing 100854China

In this paper,the satellite attitude control system subject to parametric perturbations,external disturbances,time-varying input delays,actuator faults and saturation is *** order to make the controller architecture simple and practical,the closed-loop system is transformed into a disturbance-free nominal system and an equivalent disturbance *** equivalent disturbance represents all above uncertainties and actuator failures of the original *** a robust controller is proposed in a simple composition consisting of a nominal controller and a robust *** nominal controller is designed for the transformed nominal *** robust compensator is developed from a second-order filter to restrict the influence of the equivalent *** analysis indicates that both attitude tracking errors and compensator states can converge into the given neighborhood of the origin in finite *** verify the effectiveness of the proposed control law,numerical simulations are carried out in different *** results demonstrate that the high-precision attitude tracking control can be achieved by the proposed fault-tolerant control ***,multiple system performances including the control accuracy and energy consumption index are fully discussed under a series of compensator parameters.

关键词： Actuator faults Fault-tolerant systems Input delays Multiple uncertainties Satellite attitude control

A NEW METHOD OF CHANNEL FRICTION INVERSION BASED ON KALMAN FILTER WITH UNKNOWN PARAMETER VECTOR

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Journal of Hydrodynamics 2005年第6期17卷 693-698页

作者： CHENG Wei-ping mao Gen-hai LIU Guo-hua College of Civil Engineering and Architecture Zhejiang University Hangzhou 310027 China

Channel friction is an important parameter in hydraulic analysis. A channel friction parameter inversion method based on Kalman Filter with unknown parameter vector is proposed. Numerical simulations indicate that when the number of monitoring stations exceeds a critical value, the so lution is hardly affected. In addition, Kalman Filter with unknown parameter vector is effective only at unsteady state. For the nonlinear equations, computations of sensitivity matrices are time-costly. Two simplified measures can reduce computing time, but not influence the results. One is to reduce sensitivity matrix analysis time, the other is to substitute for sensitivity matrix.

关键词： channel inversion Kalman Filter with unknown parameter vector friction

Will Coal Price Fluctuations Affect Renewable Energy Substitution and Carbon Emission? A Computable General Equilibrium-Based Study of China

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Energy Engineering 2021年第4期118卷 1009-1026页

作者： Wenhui Zhao Yibo Yin Lu mao Konglu Zhong Guanghui Yuan hai huang Yige Yang College of Economics and Management Shanghai University of Electric PowerShanghai200090China Zhejiang Electric Power Construction Co. Ltd.Ningbo315000China Zhejiang Huayun Electric Power Engineering Design Consulting Co. Ltd.Hangzhou310014China Fintech Research Institute&School of Information Management and Engineering Shanghai University of Finance and EconomicsShanghai200433China State Key Joint Laboratory of Environment Simulation and Pollution Control(SKLESPC) School of EnvironmentTsinghua UniversityBeijing10084China State Grid Integrated Energy Planning and D&R Institute Beijing10084China

Changes in the energy price system will determine the direction of evolution of the energy industry *** a country where coal is the dominant energy source,what is the effect of coal price fluctuations on China’s industry development costs and energy consumption structure?To investigate this problem,this paper utilized an economy–energy–environment computable general equilibrium *** this study,four aspects were analyzed:Energy supply side,proportion of renewable energy consumption,macroeconomy,and changes in CO_(2) *** results of this study show that an increase of 10%–20%in coal prices contributes to a shift into using renewable energy,which leads to energy saving and emission *** energy and clean energy rose by 0.57%–4.47%in the energy structure,but this has a certain negative impact on the *** gross domestic product(GDP)fell by 0.07%–0.18%.As a result,the decline in coal prices became an obstacle to renewable energy substitution and energy *** addition,we put forward policy suggestions according to the results in energy,economic,and environmental effects.

关键词： Coal price computable general equilibrium multi-scenario simulation renewable energy

Auxin polar transport flanking incipient primordium initiates leaf adaxial-abaxial polarity patterning

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Journal of Integrative Plant Biology 2018年第6期60卷 455-464页

作者： Jiaqiang Dong hai huang Waksman Institute of Microbiology Rutgers The State University of New Jersey National Laboratory of Plant Molecular Genetics Shanghai Institute of Plant Physiology and Ecology Chinese Academy of Sciences

The leaves of most higher plants are polar along their adaxial-abaxial axis, and the development of the adaxial domain （upper side） and the abaxial domain （lower side） makes the leaf a highly efficient photosynthetic organ. It has been proposed that a hypothetical signal transported from the shoot apical meristem （SAM） to the incipient leaf primordium, or conversely, the plant hormone auxin transported from the leaf primordium to the SAM, initiates leaf adaxial-abaxial patterning. This hypothetical signal has been referred to as the Sussex signal, because the research of fan Sussex published in 1951 was the first to imply its existence. Recent results, however, have shown that auxin polar transport flanking the incipient leaf primordium, but not the Sussex signal, is the key to initiate leaf polarity. Here, we review the new findings and integrate them with other recently published results in the field of leaf development, mainly focusing on the early steps of leaf polarity establishment.

关键词： Frans E. Tax University of Arizona USA

Roles of small RNAs in plant disease resistance

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Journal of Integrative Plant Biology 2014年第10期56卷 962-970页

作者： Li Yang hai huang Department of Biology University of North Carolina Chapel Hill National Laboratory of Plant Molecular Genetics Shanghai Institute of Plant Physiology and Ecology Shanghai Institutes for Biological Sciences The Chinese Academy of Sciences

The interaction between plants and pathogens represents a dynamic competition between a robust immune system and efficient infectious strategies. Plant innate immunity is composed of complex and highly regulated molecular networks, which can be triggered by the perception of either conserved or race-specific pathogenic molecular signatures. Small RNAs are emerging as versatile regulators of plant development, growth and response to biotic and abiotic stresses. They act in different tiers of plant immunity, including the pathogen-associated molecular pattern-triggered and the effector-triggered immunity. On the other hand, pathogens have evolved effector molecules to suppress or hijack the host small RNA pathways. This leads to an arms race between plants and pathogens at the level of small RNA-mediated defense. Here, we review recent advances in small RNA-mediated defense responses and discuss the challenging questions in this area.

关键词： Effector-triggered immunity microRNA pathogen-associated molecular pattern-triggered immunity small interfering RNA

Study of Impact Resistance Based on Porcupine Quills Bionic Thin-walled Structure

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Journal of Bionic Engineering 2023年第5期20卷 1942-1955页

作者： Tianshu huang Zhengyu mao Lijun Chang Xingyuan huang Zhihua Cai Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment Hunan University of Science and TechnologyXiangtanChina School of Mechanical Engineering Hunan University of Science and TechnologyXiangtanChina

Using an electron microscope to observe the microstructure of a porcupine quills cross-section and a bionic method,a new bionic structure was *** performance of the structure in terms of energy absorption,maximum impact force withstood,and impact force efficiency was evaluated using Ansys finite element simulation software to simulate the structure's *** examine the impact of ribs on the structural performance of the bionic porcupine quills,a control structure was *** to the results of the finite element simulation,the presence of ribs in the Bionic porcupine quills structure can transfer stress uniformly to the overall structure and share stress for some of the rupture-prone *** reduce stress concentration in specific areas and increase the impact force efficiency of the *** SEA and IFE values of bionic porcupine quills were 30.01 kJ/kg and 84.22%,*** structure is then optimized for parameter design in order to find the optimal structure by response surface in order to improve the structure's SEA and decrease its *** order to evaluate the precision of the response surface,the optimal structure predicted is validated using finite element simulation.

关键词： Bionic structure design Thin-walled structure Impact resistance Specific energy absorption Multi-objective optimization

Synthesis of 1,3-benzothiazines by intramolecular dehydrogenative C–S cross-coupling in a flow electrolysis cell

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Science China Chemistry 2019年第11期62卷 1501-1503页

作者： Chong huang hai-Chao Xu State Key Laboratory of Physical Chemistry of Solid Surfaces Innovative Collaboration Center of Chemistry for Energy MaterialsKey Laboratory of Chemical Biology of Fujian Province College of Chemistry and Chemical Engineering Xiamen University

Dehydrogenative cyclization of thioamides is an attractive approach for the synthesis of *** herein is an electrochemical dehydrogenative cyclization reaction of N-benzyl thioamides in a flow electrolysis *** continuous-flow electrosynthesis has addressed the limitations associated with previously reported methods for the cyclization of alkylthioamides and provide a transition metal-and oxidizing reagent-free access to various functionalized 1,3-benzothiazines in good yields.

关键词： C-H functionalization electrochemistry flow chemistry heterocycles

Alkaloids from Stems of Ervatamia yunnanensis （Ⅱ）

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Chinese Chemical Letters 2006年第6期17卷 783-786页

作者： Shuang LIANG Xin Gen LUO hai Sheng CHEN Xiao Dong ZHANG mao huang Wen Yong LIU College of Pharmacy Second Military Medical University Shanghai 200433 Deoartment of Pharmacy Guangzhou Military General Hospital Guangzhou 510010 Center of New Drug Evaluation Institute of Basic Medical Sciences Second Military Medical University Shanghai 200433

Six indole alkaloids were isolated from the stems of Ervatamia yunnanensis. Among them, 10-hydroxy-19, 20-dihydroisositsirikine （I） is new. The other five are known alkaloids, namely： matrine （Ⅱ）, 19, 20-dihydroisositsirikine （Ⅲ）, 19-s-voacangarine （Ⅳ）, 1 l＇-methoxyl-19s- heyneanine （Ⅴ）, conodurine （Ⅵ）. The structural elucidation of the alkaloids was based on spectral means.

关键词： Ervatamia yunnanensis indole alkaloids.