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Design and simulation of a standing wave oscillator based PLL

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Frontiers of Information Technology & Electronic Engineering 2016年第3期17卷 258-264页

作者： Wei ZHANG You-de hu Li-rong ZHENG State Key Lab of ASIC & System Fudan University Pack Vinn Excellence Center School of ICTRoyal Institute of Technology (KTH) Eletrum 229

A standing wave oscillator(SWO) is a perfect clock source which can be used to produce a high frequency clock signal with a low skew and high reliability. However, it is difficult to tune the SWO in a wide range of frequencies. We introduce a frequency tunable SWO which uses an inversion mode metal-oxide-semiconductor(IMOS) field-effect transistor as a varactor, and give the simulation results of the frequency tuning range and power dissipation. Based on the frequency tunable SWO, a new phase locked loop(PLL) architecture is presented. This PLL can be used not only as a clock source, but also as a clock distribution network to provide high quality clock signals. The PLL achieves an approximately 50% frequency tuning range when designed in Global Foundry 65 nm 1P9 M complementary metal-oxide-semiconductor(CMOS) technology, and can be used directly in a high performance multi-core microprocessor.

关键词： Standing wave oscillator (SWO) Clock distribution Phase locked loop (PLL) Varactor

Effect of Cu content on microstructure and properties of Fe-16Cr-2.5Mo damping alloy

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Journal of Materials Science & Technology 2018年第5期34卷 774-781页

作者： Xiaofeng hu Yubin Du Desheng Yan Lijian rong CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China

Five Fe-16 Cr-2.5 Mo damping alloys with different Cu contents（0%,0.25%,0.5%,1.0% and 2.0%） were *** microstructure was observed by scanning transmission electron microscopy（STEM） and the damping behavior was measured by using a dynamic mechanical analyzer（DMA）.The results show that the grain size of experimental alloy with（0.25–1.0%） Cu was refined compared with the 0 Cu *** Cu element is fully dissolved in the matrix and there are no Cu precipitates and carbides *** the internal stress increases because of Cu addition,the damping capacity of the 0.5 Cu and1.0 Cu alloys has been significantly *** reason of damping improvement is that the magnetic domain structure is strongly ***,the strength was improved gradually due to the Cu solid solution strengthening and grain *** the 2.0 Cu alloy,lots of Cu-riched particles appeared in the *** Cu precipitates with 10–15 nm in size are spherical and homogeneously distributed,which strongly induce strength improvement through precipitation *** the contrary,the elongation and impact energy of the 2.0 Cu alloy decrease *** addition,lots of Cu precipitates will significantly decrease the damping capacity by hindering the mobility of domain walls.

关键词： Fe-16Cr-2.5Mo alloy Cu Damping capacity Strength Precipitation

DYNAMICS OF FREE STRAIGHT SWIMMING OF ANGULLA ANGULLA INCLUDING FORWARD,BRAKING AND BACKWARD LOCOMOTION

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Journal of Hydrodynamics 2007年第4期19卷 395-402页

作者： hu Wen-rong TONG Bing-gang LIU Hao Department of Engineering Mechanics Shanghai Jiaotong University Shanghai 200240 China Laboratory for Biomechanics of Animal Locomotion Graduate University of the Chinese Academy of Sciences Beijing 100039 China Department of Electronics and Mechanical Engineering Chiba University Japan

Eels can swim backward by reversing the direction of the traveling wave along the body. The propulsive mechanism of an eel, angulla angulla, during its self-propelled straight swimming, including forward swimming, braking and switching direction to backward swimming was numerically studied. The problem was reasonably simplified to a loose-coupling problem of fish swimming dynamics and hydrodynamics only in the swimming direction. The approach involved the simulation of the flow by solving the two-dimensional unsteady incompressible N-S equations and the fish motion dynamic problem with Newton＇s second law. Visualizations of flow fields and vortex structures were performed. The propulsive mechanism and dynamics during each process were investigated and the effects of controllable factors on forward free swimming were discussed.

关键词： self-propelled propulsive mechanism Navier-Stokes equations coupling problem

First principles study of Fenton reaction catalyzed by FeOCl:reaction mechanism and location of active site

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Rare Metals 2019年第8期38卷 783-792页

作者： Xuan-Xuan Ji Hai-Feng Wang pei-Jun hu Key Laboratory for Advanced Materials Research Institute of Industrial Catalysis and Centre for Computational Chemistry School of Chemical and Molecular Engineering East China University of Science and Technology Shanghai 200237 China School of Chemistry and Chemical Engineering The Queen’s University of Belfast Belfast BT9 5AZ UK

Fe-based solid catalysts in promoting Fenton reaction to generate ·OH radical has drawn much attention,and interestingly,FeOCl was reported to have superior activity compared with the traditional Fe2 O3 ***,the mechanism of Fenton reaction on FeOCl and the origin of high activity remain ***,by virtue of DFT+ U calculations,the H2 O2 decomposition and conversion mechanism on FeOCl(100)surface were systematically *** is found that on clean FeOCl(100)surface,the exposed[Fe^3+-Fe^3+]sites can hardly break O-O bond of H2 O2 into OH groups,but instead H2 O2 tends to dehydrogenate by the surface lattice O,resulting in a series of side reactions and final conversion into O2,while the left H atoms gradually saturate the surface lattice O and reduce Fe^3+ into Fe^2+.On fully H-covered FeOCl(100),H2O2 can efficiently dissociate at[Fe^2+-Fe^2+]sites into two OH,but OH binds with Fe^2+ so strongly that it cannot desorb as OH radical as easily as that on Fe^3+.Interestingly,FeOCl(100)tends to be partially protonated in the real acid solution,which,along with H2 O2 dehydrogenation,results in the formation of active unit [Fe^2+-Fe^3+].On[Fe^2+-Fe^3+]unit,H2 O2 can easily break its O-O bond and OH at Fe3+ can desorb as OH radical,while the other OH at Fe^2+ couples with the surface H into H2O and finish the catalytic *** comparison,Fe2 O3(012)cannot provide enough [Fe^2+-Fe^3+] active units due to the relative difficulty in H2 O2 dehydrogenation,which accounts for its inferior catalytic efficiency for Fenton reaction.

关键词： Fenton reaction FeOCl Density functional theory H2O2 Active site

Multi-type sensor placement and response reconstruction for building structures: Experimental investigations

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Earthquake Engineering and Engineering Vibration 2018年第1期17卷 29-46页

作者： rong-Pan hu You-Lin Xu Sheng Zhan Department of Civil and Environmental Engineering The Hong Kong Polytechnic University

Estimation of lateral displacement and acceleration responses is essential to assess safety and serviceability of high-rise buildings under dynamic loadings including earthquake excitations. However, the measurement information from the limited number of sensors installed in a building structure is often insufficient for the complete structural performance assessment. An integrated multi-type sensor placement and response reconstruction method has thus been proposed by the authors to tackle this problem. To validate the feasibility and effectiveness of the proposed method, an experimental investigation using a cantilever beam with multi-type sensors is performed and reported in this paper. The experimental setup is first introduced. The finite element modelling and model updating of the cantilever beam are then performed. The optimal sensor placement for the best response reconstruction is determined by the proposed method based on the updated FE model of the beam. After the sensors are installed on the physical cantilever beam, a number of experiments are carried out. The responses at key locations are reconstructed and compared with the measured ones. The reconstructed responses achieve a good match with the measured ones, manifesting the feasibility and effectiveness of the proposed method. Besides, the proposed method is also examined for the cases of different excitations and unknown excitation, and the results prove the proposed method to be robust and effective. The superiority of the optimized sensor placement scheme is finally demonstrated through comparison with two other different sensor placement schemes： the accelerometer-only scheme and non-optimal sensor placement scheme. The proposed method can be applied to high-rise buildings for seismic performance assessment.

关键词： experimental investigation multi-type sensors inclinometer response reconstruction optimal sensor placement

Equitable Presentations for Multiparameter Quantum Groups

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Acta Mathematica Sinica,English Series 2021年第10期37卷 1560-1572页

作者： Nai Hong hu Yu Feng pei Jiao ZHANG School of Mathematical Sciences SKLPMMPEast China Normal UniversityShanghai 200241P.R.China Department of Mathematics Shanghai Normal UniversityShanghai 200234P.R.China Department of Mathematics Shanghai UniversityShanghai 200444P.R.China

In this paper, we give an equitable presentation for the multiparameter quantum group associated to a symmetrizable Kac–Moody Lie algebra, which can be regarded as a natural generalization of the Terwilliger's equita... 详细信息

关键词： Quantum groups equitable presentation Hopf algebras

An adaptive hyper parameter tuning model for ship fuel consumption prediction under complex maritime environments

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Journal of Ocean Engineering and Science 2022年第3期7卷 255-263页

作者： Tianrui Zhou Qinyou hu Zhihui hu rong Zhen Merchant Marine College Shanghai Maritime University1550 Haigang AvenuePudong New AreaShanghaiChina Navigation College Jimei UniversityXiamen 361021FujianChina

An accurate prediction of ship fuel consumption is critical for speed,trim,and voyage optimisation *** previous studies have focused on predicting ship fuel consumption with respect to a variety of factors,research on the impact of environmental factors on fuel consumption has been *** addition,although recent research efforts have widely focused on machine learning methods to predict fuel consumption,studies on hyperparameter values that are suitable for these prediction models are *** compensate for this deficiency in existing literature,an adaptive hyperparameter tuning method is proposed,and the effects of maritime environmental factors on fuel consumption are taken into *** experimentation,the proposed adaptive hyperparameter tuning method was validated via artificial neural network(ANN),support vector regression(SVR),random forest(RF),and least absolute shrink-age and selection operator(Lasso).The hyperparameter tuning proportionally increased the amplitudes of the coefficients of determination(R 2)of these *** increase of the amplitude demonstrated the following trend,in the order of the largest increase to the lowest increase:ANN,Lasso,SVM,and *** rates of increase were between 0.0773%and 2.1653%.Furthermore,after the environmental factors were considered,the prediction accuracies of the ANN and Lasso increased;however,the opposite was observed for the SVR and *** such,we confirmed that the use of Bayesian optimisation for hyper-parameter tuning can effectively improve the fuel consumption prediction accuracy,and our proposed model can therefore serve as a significant reference for calculating fuel consumption.

关键词： Ship fuel consumption Artificial neural network Bayesian optimization Hyperparameter tuning Environmental factors

Tf_2O-TMDS combination for the direct reductive transformation of secondary amides to aldimines,aldehydes, and/or amines

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Science China Chemistry 2016年第12期59卷 1638-1644页

作者： Qi-Wei Lang Xiu-Ning hu pei-Qiang huang Department of Chemistry Fujian Provincial Key Laboratory of Chemical Biology Collaborative Innovation Center of Chemistry for Energy Materials College of Chemistry and Chemical Engineering Xiamen University

The direct partial reduction of highly stable secondary amides to more reactive aldimines and aldehydes is a challenging yet highly demanding transformation. In this context, only three methods have been reported. We report herein an improved version of the Charette's method. Our protocol consists of activation of secondary amides with triflic anhydride/2-fluoropyridine,and partial reduction of the resulting intermediates with 1,1,3,3-tetramethyldisiloxane(TMDS), which delivered aldimines or aldehydes upon acidic hydrolysis. Aromatic amides were reduced to the corresponding aldimines in 85%–100% NMR yields,and yields(NMR) from aliphatic amides were 72%–86%. Acidic hydrolysis of the aldimine intermediates afforded, in one-pot,the corresponding aldehydes in 80%–96% yields. A simple protocol was established to isolate labile aldimines in pure form in92%–96% yields. The improved method gave generally higher yields as compared to the known ones, and features the use of cheaper and more atom-economical TMDS as a chemoselective reducing agent. In addition, a convenient extraction protocol has been established to allow the isolation of amines, which constitutes a mild method for the N-deacylation of amides, another highly desirable transformation. The extended method retains the advantages of the original method of Charette in terms of mild conditions, good functional group tolerance, and excellent chemoselectivity.

关键词： secondary amides amide activation partial reduction aldimines N-deacylation

Unraveling the Heterogeneity of Epoxy-amine Networks by Introducing Dynamic Covalent Bonds

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Chinese Journal of Polymer Science 2023年第6期41卷 926-932,I0009页

作者： hu Xu Yao Zhang Hao Wang Jin-rong Wu State Key Laboratory of Polymer Materials Engineering College of Polymer Science and EngineeringSichuan UniversityChengdu 610065China

Epoxy resins are a kind of universal thermosetting plastics,which are widely used as structural materials in various ***,it is necessary to understand the network structure of epoxy ***,it is challenging to reveal the network heterogeneity of epoxy resins due to the permanent covalent ***,we provide a novel strategy to characterize the network heterogeneity of epoxy resins by using the dynamic covalent bonds to replace the conventional covalent *** dynamic covalent bonds can reorganize under heat stimulus and the network keeps a constant crosslinking density during topological rearrangement,making it convenience to study the heterogeneity of epoxy ***-Williams-Watts(KWW)stretched exponential function is used to fit the stress relaxation data,and the parametersβandσperm/σ0 extracted from KWW equation indicate the network becomes more homogenous with the stoichiometric ratio of epoxy groups and amines decreases from 1/1 to 1/*** method proves that the side reaction between epoxy and hydroxyl is the main origin of the structural heterogeneity in epoxy resins compared to the secondary amines network.

关键词： resins bonds amines