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On the Boundary Condition and Related Instability in the Smoothed Particle Hydrodynamics

Communications in Theoretical Physics 2019年第11期71卷 1281-1292页

作者： Chong Ye Jin Li Kai Lin Wei-Liang Qian College of Physics Chongqing UniversityChongqing 401331China Centro Brasileiro de Pesquisas Fisicas 22290-180Rio de JaneiroRJBrazil Institute of Geophysics and Geoinforma tics China University of GeosciencesWuhan 430074China Escola de Engenharia de Lorena Universidade de Sao Paulo12602-810LorenaSPBrazil Faculdade de Engenharia de Guaratinguetá Universidade Estadual Paulista12516-410GuaratinguetaSPBrazil School of Physical Science and Technology Yangzhou UniversityYangzhou 225002China

In this work, we explore various relevant aspects of the Smoothed Particle Hydrodynamics regarding Burger's equation. The stability, precision, and efficiency of the algorithm are investigated in terms of different *** particular, we argue that the boundary condition plays an essential role in the stability of numerical ***, the issue is shown to be closely associated with the initial particle distribution and the interpolation *** others, we introduce an interpolation scheme termed symmetrized finite particle method. The main advantage of the scheme is that its implementation does not involve any derivative of the kernel function. Concerning the equation of motion, the calculations are carried out using two distinct scenarios, where the particles are chosen to be either stationary or dynamically evolved. The obtained results are compared with those obtained by using the standard finite difference method for spatial derivatives. Our numerical results indicate subtle differences between different schemes regarding the choice of boundary condition. In particular, a novel type of instability is observed where the regular distribution is compromised as the particles start to traverse each other. Implications and further discussions of the present study are also addressed.

关键词： hydrodynamic model SPH algorithm pair instability

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Predicting solutions of the stochastic fractional order dynamical system using machine learning

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Theoretical & Applied Mechanics Letters 2023年第3期13卷 188-198页

作者： Zi-Fei Lin Jia-Li Zhao Yan-Ming Liang Jiao-Rui Li School of Statistics Xi’an University of Finance and EconomicsXi’an 710100China Xi’an University of Finance and Economics China(Xi’an)Institute for Silk Road ResearchXi’an 710100China

The solution of fractional-order systems has been a complex problem for our *** methods like the predictor-corrector method and other solution steps are complicated and cumbersome to derive,which makes it more difficult for our solution *** development of machine learning and nonlinear dynamics has provided us with new ideas to solve some complex ***,this study considers how to improve the accuracy and efficiency of the solution based on traditional ***,we propose an efficient and accurate nonlinear auto-regressive neural network for the fractional order dynamic system prediction model(FODS-NAR).First,we demonstrate by example that the FODS-NAR algorithm can predict the solution of a stochastic fractional order ***,we compare the FODS-NAR algorithm with the famous and good reservoir computing(RC)*** find that FODS-NAR gives more accurate predictions than the traditional RC algorithm with the same system parameters,and the residuals of the FODS-NAR algorithm are closer to ***,we conclude that the FODS-NAR algorithm is a method with higher accuracy and prediction results closer to the state of fractional-order stochastic *** addition,we analyze the effects of the number of neurons and the order of delays in the FODS-NAR algorithm on the prediction results and derive a range of their optimal values.

关键词： Fractional-order dynamical system Gaussian white noise Deep learning FODS-NAR algorithm

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DISSIPATION AND DISPERSION APPROXIMATION TO HYDRODYNAMICAL EQUATIONS AND ASYMPTOTIC LIMIT

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Journal of Partial Differential Equations 2008年第1期21卷 59-76页

作者： Hsiao Ling Li Hailiang Academy of Mathematics and Systems Science CAS Beijing 100080 China Department of Mathematics Capital Normal University Beijing 100037 China

The compressible Euler equations with dissipation and/or dispersion correction are widely used in the area of applied sciences, for instance, plasma physics, charge transport in semiconductor devices, astrophysics, geophysics, etc. We consider the compressible Euler equation with density-dependent （degenerate） viscosities and capillarity, and investigate the global existence of weak solutions and asvmototic limit.

关键词： Hydrodynamics degenerate viscosities dispersion limit.

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Reactions of fluoroalkanesulfonyl azides with trimethylsilyl enol ethers

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厦门大学学报（自然科学版） 1999年第S1期38卷 233-233页

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Sulfur-enriched alkaloids from the root of Isatis indigotica

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Acta Pharmaceutica Sinica B 2018年第6期8卷 933-943页

作者： Qinglan Guo Chengbo Xu Minghua Chen Sheng Lin Yuhuan Li Chenggen Zhu JiANDong Jiang Yongchun Yang Jiangong Shi State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia Medica Chinese Academy of Medical Sciences & Peking Union Medical College Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences & Peking Union Medical College

Five new sulfur-enriched alkaloids isatithioetherins A–E(1–5), and two pairs of scalemic enantiomers(t)-and( à)-isatithiopyrin B(6 a and 6 b) and isoepigoitrin and isogoitrin(7 a and 7 b), along with the known scalemic enantiomers epigoitrin and goitrin(8 a and 8 b), were isolated and characterized from an aqueous extract of the Isatis indigotica roots. Their structures were determined by extensive spectroscopic data analysis, including 2 D NMR and theoretical calculations of electronic circular dichroism(ECD) spectra based on the quantum-mechanical time-dependent density functional theory(TDDFT). Compounds 1–5 represent a novel group of sulfur-enriched alkaloids, biogenetically originating from stereoselective assemblies of epigoitrin-derived units. Isolation and structure characterization of 6 a and 6 b support the postulated biosynthetic pathways for the diastereomers 9 a and 9 b via a rare thio-Diels–Alder reaction. Compounds 2 and 4 showed antiviral activity against the influenza virus A/Hanfang/359/95(H3 N2, IC500.60 and 1.92 μmol/L) and the herpes simplex virus 1(HSV-1, IC503.70 and 2.87 μmol/L), and 2 also inhibited Coxsackie virus B3(IC500.71 μmol/L).& 2018 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license(http://***/licenses/by-nc-nd/4.0/).

关键词： Cruciferae Isatis indigotica Sulfur-containing alkaloids Isatithioetherins A–E Isatithiopyrins A and B Isoepigoitrin Isogoitrin Antiviral activity

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Microstructure and Properties of Multi-component AlxCoCrFeNiTi0.5 High-entropy Alloys

Microstructure and Properties of Multi-component AlxCoCrFeNi...

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中国材料大会2012

作者： Yong Dong Yiping Lu Junjia Zhang Tingju Li School of Materials Science and Engineering Dalian University of Technology

ISBN: (纸本)9783037856079

The multi-component AlxCoCrFeNiTi0.5 （x=0, 0.2, 0.5, 0.8, 1.0） high-entropy alloys were prepared by vacuum arc melting. The microstructure and mechanical properties were studied. It was found that the structure transformed from FCC into FCC + BCC + Laves, and finally into BCC with the increase of Al content. The compress test results showed that with the addition of aluminium from 0 to 1.0, the fraction strength increased while plasticity reduced. In the stain rates of 5×10-3 /s and 1×10-3 /s, when x=0.8 the fraction strength achieved maximum and x=0 the plastic was best, the strength of 2879MPa and 2433MPa, the strain of 0.21 and 0.22, respectively. The hardness increased obviously （from Hv479.1 to Hv692.7） when Bcc phase and Laves phase appeared. The analysis revealed that the strengthen mechanism was mainly composed of solid solution strengthening and precipitation strengthening.

关键词： Multi-component High-entropy alloys Microstructure Solid solution Fracture strength

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Optically Active β-Hydroxy Carbonyl Compound from a Mukaiyama Reaction Catalyzed by M-Salen Complex

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厦门大学学报（自然科学版） 1999年第S1期38卷 227-227页

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Reaction of 4-Ethoxyl-1,1,1-trifluoromethyl-3-butenone with perfluorophenyl hydrazine and perfluoroalkyl hydrazides

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厦门大学学报（自然科学版） 1999年第S1期38卷 238-238页

The presence of fluorine in biologically active compounds can impart a profound influence on their biological active. This influence has lead to the development of several potent agricultural and therapeutic agents[1]. During the study on the reactions of 4 - ethoxyl - 1, 1, 1 -trifluoromathyl-3-butenone 1, we found which is a very useful building-block in synthesis of fluoro-containing heterocyclic compounds[2]. Compound 1 can react with perfluorophenyl hydrazine and afford 1- perfluorophenyl-5-trifluoromethyl- 5 -hydroxy-4, 5 -2H- pyrazole 2 in excellent yield. It’s structure is further supported by X-ray diffraction.

关键词： Reaction of 4-Ethoxyl-1,1,1-trifluoromethyl-3-butenone with perfluorophenyl hydrazine and perfluoroalkyl hydrazides

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Insight into Medicinal Chemistry Behind Traditional Chinese Medicines: p-Hydroxybenzyl Alcohol-Derived Dimers and Trimers from Gastrodia elata

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Natural Products and Bioprospecting 2021年第1期11卷 31-50页

作者： Yanan Wang Min Zhang Xue Zhou Chengbo Xu Chenggen Zhu Yuhe Yuan Naihong Chen Yongchun Yang Qinglan Guo Jiangong Shi State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China

From an aqueous extract of“tian ma”(the steamed and dried rhizomes of Gastrodia elata),ten new compounds gastrodiben-zins A−D(1−4)and gastrotribenzins A−F(5−10),along with known analogues(11−20),having structure features coupling between two and three p-hydroxybenzyl-derived units via carbon-and/or ether-bonds,were isolated and characterized by spectroscopic data ***,the new compounds 5a,6a,8a,22,and 23,as well as the known derivatives 13a,14a,15,17−21,24,25,and p-hydroxybenzyl aldehyde were isolated and identified from a refluxed aqueous solution of p-hydroxybenzyl *** of 5a and 6a in methanol and ethylation of 6a,8a,13a,and 14a in ethanol produced 5 and 6 and 7,8,13,and 14,*** ultra-performance liquid chromatography high-resolution electrospray ioniza-tion mass spectrometry(UPLC-HRESIMS)analysis of the refluxed solutions of p-hydroxybenzyl alcohol and the refluxed extracts of the fresh *** rhizome and“tian ma”extracts indicated consistent production and variation of the dimeric and trimeric derivatives of p-hydroxybenzyl alcohol upon extracting solvents and refluxing *** various assays,the dimeric and trimeric derivatives showed more potent activities than p-hydroxybenzyl alcohol itself and gastrodin,which are the main known active constituents of“tian ma”.These results revealed for the first time that the more effective dimers and trimers can be produced through condensation of the co-occurring p-hydroxybenzyl alcohol during processing and decocting of the *** rhizomes,demonstrating insights into medicinal chemistry behind application protocols of traditional Chinese medicines.

关键词： Orchidaceae Gastrodia elata p-Hydroxybenzyl alcohol dimer p-Hydroxybenzyl alcohol trimer Gastrodibenzins Gastrotribenzins Medicinal chemistry behind Chinese medicines

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Measurement, modelling, and closed-loop control of crystal shape distribution： Literature review and future perspectives

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Particuology 2016年第3期14卷 1-18页

作者： Cai Y. Ma Jing J. Liu Xue Z. Wang Institute of Particle Science and Engineering School of Chemical and Process Engineering University of Leeds Leeds 1.52 9JT United Kingdom School of Chemistry and Chemical Engineering South China University of Technology Guangzhou 510640 China

Crystal morphology is known to be of great importance to the end-use properties of crystal products, and to affect down-stream processing such as filtration and drying. However, it has been previously regarded as too challenging to achieve automatic closed-loop control. Previous work has focused on controlling the crystal size distribution, where the size of a crystal is often defined as the diameter of a sphere that has the same volume as the crystal. This paper reviews the new advances in morphological population balance models for modelling and simulating the crystal shape distribution （CShD）, measuring and estimating crystal facet growth kinetics, and two- and three-dimensional imaging for on-line characterisation of the crystal morphology and CShD. A framework is presented that integrates the various components to achieve the ultimate objective of model-based closed-loop control of the CShD. The knowledge gaps and challenges that require further research are also identified.

关键词： Crystal morphology Crystal shape distribution Morphological population balance mode3D process imaging Closed-loop control of crystal shapeCrystal facet growth kinetics

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