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First Total Synthesis of （±）-Latifolin and Its Antioxidant Mechanism

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Chinese Journal of Chemistry 2015年第11期33卷 1287-1292页

作者： Yihua Dai Qiaoling liu Zhifang Li Weifeng Chen zhongli liu Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education Hangzhou Normal University Hangzhou Zhejiang 310012 China National Laboratory of Applied Organic Chemistry Lanzhou University Lanzhou Gansu 730000 China

The first total synthesis of （±）-latifolin has been accomplished in six steps and 47.8% overall yield. To understand the relative importance of phenolic O-H and benzhydryl C-H hydrogen on the antioxidant activity of latifolin, 2,2-diphenyl-1-picrylhydrazyl （DPPH） radical scavenging assay and density functional theory （DFT） studies were carried out. On scavenging DPPH radical in ethanol, the activity of latifolin （1） bearing phenolic hydrogen is remarkably higher than analogue 10 bearing no phenolic hydrogen. Therefore, Phenolic hydrogen is responsible for latifolin＇s antioxidant activity rather than benzhydryl C-H hydrogen. Furthermore, the 5-OH BDE is lower than 2＇-OH and 7-CH BDEs by a DFT calculation, respectively. Based on theoretical results it is definitely concluded that the phenolic 5-OH plays a major role in the antioxidant activity of latifolin.

关键词： total synthesis latifolin antioxidant DPPH-scavenging density functional theory

Effect of tempering temperature on microstructure and mechanical properties of high boron white cast iron

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China Foundry 2012年第4期9卷 313-317页

作者： liu zhongli Li Yanxiang Chen Xiang Technical Center Yantai Taihai Manoir Nuclear Equipment Co.Ltd.Yantai 264003China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationDepartment of Mechanical EngineeringTsinghua UniversityBeijing 100084China

The effect of different tempering temperatures on the microstructure and mechanical properties of airquenched high boron white cast iron was *** results indicate that the high boron white cast iron comprises dendritic matrix and inter-dendritic M 2 B boride;and the matrix comprises martensite and *** quenching in the air,the matrix is changed into lath martensite;but only 1-μm-size second phase exists in the *** tempering,another second phase of several tens of nanometers is found in the matrix,and the size and quantity increase with an increase in tempering *** two kinds of second precipitation phase with different sizes in the matrix have the same chemical formula,but their forming stages are *** precipitation phase with larger size forms during the austenitizing process,while the precipitation phase with smaller size forms during the tempering *** tempered at different temperatures after quenching,the hardness decreases with an increase in the tempering temperature,but it increases a little at 450 ℃ due to the precipitation strengthening effect of the second phase,and it decreases greatly due to the martensite decomposition above 450 ℃.The impact toughness increases a little when tempered below 300 ℃,but it then decreases continuously owing to the increase in size and quantity of the secondary precipitate above 300 ℃.Considered comprehensively,the optimum tempering temperature is suggested at 300 ℃ to obtain a good combination of hardness and toughness.

关键词： high boron white cast iron boride quenching tempering

Inhibition of free radical induced oxidative hemolysis of red blood cells by green tea polyphenols

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Chinese Science Bulletin 2000年第22期45卷 2052-2056页

作者： Lanping Ma Zaiqun liu Bo Zhou Li Yang zhongli liu Lanzhou Univ State Key Lab Appl Org Chem Lanzhou 730000 Peoples R China

The in vitro oxidative hemolysis of human red blood cells (RBC) was used as a model to study the free radical induced damage of biological membranes and the inhibitory effect of natural antioxidants. The hemolysis was induced by a water-soluble free radical initiator 2,2’-azo(2-asmidinopropane)dihydrochloride (AAPH) and inhibited by the principal polyphenolic components extracted from green tea leaves, i.e. (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicat-echin gallate (ECG), (-)-epigallocatechin gallate (EGCG) and gallic acid (GA). Addition of AAPH at 37℃ caused fast hemolysis after a short period of inhibition period, while addition of the green tea polyphenols efficiently suppressed the hemolysis in the activity sequence of EGCG > EGC> ECG ≈EC>GA, demonstrating that these green tea polyphenols are effective antioxidants which could protect biological membranes from free radical induced oxidative damage.

关键词： free radical red blood cell hemolysis antioxidant green tea polyphenol.

Seaweed pattern formation in the non-axially directional solidification of 2D-like and 3D Al-3 wt.% Mg single crystal

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Journal of Materials Science & Technology 2023年第16期147卷 1-5页

作者： Yumin Wang Bin Yang Shuangming Li Xin Cao zhongli liu Hui Xing College of Nuclear Equipment and Nuclear Engineering Yantai UniversityYantai 264005China Inner Mongolia Metal Material Research Institute Yantai 264003China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Shaanxi Key Laboratory of Condensed Matter Structure and PropertiesNorthwestern Polytechnical UniversityXi’an 710129China

*** Microstructures are at the centre of materials science and engineering and play an essential role in determining the in-service mechanical properties of metallic alloys[1–4].Extensive theoretical and experimental investigations have been undertaken to describe and determine solidification microstructures as a function of solidification *** seaweed pattern is one of the most important classes of microstructural patterns[5–7].The characteristic of this pattern is that its extending tips—unlike the behaviour observed in needle-like dendrites—split repeatedly into two or more parts.

关键词： solidification pattern directional

Mechanisms of two-stage martensitic transformation in Ti-Ni-Hf alloy powder

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Progress in Natural Science:Materials International 2021年第5期31卷 749-754页

作者： zhongli liu Xinxin Feng Xiaoyang Yi Kuishan Sun Haizhen Wang Zhiyong Gao Xianglong Meng College of Nuclear Equipment and Nuclear Engineering Yantai University School of Materials Science and Engineering Harbin Institute of Technology

The Ti-Ni-Hf shape memory alloy powders were prepared by plasma rotating electrode *** the powders were featured with the perfect sphericity and smooth ***,the grain size was refined in the Ti-Ni-Hf alloy powders due to the rapid cooling rate during plasma rotating electrode *** was found that the Ti-NiHf alloy powders had the typical self-accommodation configuration including spear-like,mosaic-like and lath-like *** twins,such as (001) compound twin,(011) type I twin as well as{111}type I twin,were observed in Ti-Ni-Hf alloy *** from the bulk Ti-Ni-Hf alloy,two-stage transformation corresponding to B2■B19’martensitic transformation was detected in the as-received Ti-Ni-Hf alloy *** addition,the martensitic transformation behaviors were closely related to the annealing *** Ti-NiHf alloy powders with low annealing temperature of 500~°C still exhibited two-stage martensitic transformation,while two-stage martensitic transformation changed into single martensitic transformation in the Ti-Ni-Hf alloy powders with the higher annealing temperature of 900~°*** finally the possible mechanisms for the evolution of martensitic transformation behaviors were discussed.

关键词： Ti-Ni-Hf alloy Powders Shape memory shape PREP Martensitic transformation Microstructure

Two Families of Multipoint Root-Solvers Using Inverse Interpolation with Memory

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Journal of Applied Mathematics and Physics 2023年第3期11卷 746-759页

作者： zhongli liu Quan Zheng Institute of Mathematics and Physics Beijing Union University Beijing China College of Sciences North China University of Technology Beijing China

In this paper, a general family of derivative-free n + 1-point iterative methods using n + 1 evaluations of the function and a general family of n-point iterative methods using n evaluations of the function and only one evaluation of its derivative are constructed by the inverse interpolation with the memory on the previous step for solving the simple root of a nonlinear equation. The order and order of convergence of them are proved respectively. Finally, the proposed methods and the basins of attraction are demonstrated by the numerical examples.

关键词： Nonlinear Equation General Multipoint Iteration Inverse Interpolation Order of Convergence Basin of Attraction

Gauss-Legendre Iterative Methods and Their Applications on Nonlinear Systems and BVP-ODEs

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Journal of Applied Mathematics and Physics 2016年第11期4卷 2038-2046页

作者： zhongli liu Guoqing Sun College of Biochemical Engineering Beijing Union University Beijing China College of Renai Tianjin University Tianjin China

In this paper, a group of Gauss-Legendre iterative methods with cubic convergence for solving nonlinear systems are proposed. We construct the iterative schemes based on Gauss-Legendre quadrature formula. The cubic convergence and error equation are proved theoretically, and demonstrated numerically. Several numerical examples for solving the system of nonlinear equations and boundary-value problems of nonlinear ordinary differential equations (ODEs) are provided to illustrate the efficiency and performance of the suggested iterative methods.

关键词： Iterative Method Gauss-Legendre Quadrature Formula Nonlinear Systems Third-Order Convergence Nonlinear ODEs

Oxidative coupling of cinnamic acid derivatives and their radical-scavenging activities

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Chinese Science Bulletin 2010年第25期55卷 2885-2890页

作者： JIN XiaoLing YANG RuTing SHANG YaJing DAI Fang QIAN YiPing CHENG LiXia ZHOU Bo liu zhongli State Key Laboratory of Applied Organic Chemistry Lanzhou University Lanzhou 730000 China

4-Hydroxycinnamic acid derivatives,including ferulic acid (FA) (1),sinapic acid (SA) (2) and caffeic acid (CA) (3),are widely distributed in the plant kingdom,and undergo oxidative cross-coupling leading to the corresponding dehydrodimers,trimers and even higher oligomers in plants. In order to evaluate the antioxidative ability of these 4-hydroxycinnamic acid derivatives and their oligomers,we synthesized 8-8'-bis-lactone-dimers (8-8'-DiFA (4),8-8'-DiSA (5) and 8-8'-DiCA (6)),as well as a new trimer (7),by the reaction of the corresponding monomers (1-3) with Ag2O in methanol,and assayed their free radical-scavenging activity by the reaction with 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·). It was found that CA (3) and 8-8'-DiCA (6) bearing o-dihydroxyl groups exhibited significantly higher radical-scavenging activity than those bearing no such groups,and oxidative coupling of CA (3) resulted in remarkable enhancement in the activity.

关键词：氧化偶联衍生物肉桂酸自由基清除 DPPH自由基抗氧化能力羟基酸低聚物

A New Newton-Type Method with Third-Order for Solving Systems of Nonlinear Equations

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Journal of Applied Mathematics and Physics 2015年第10期3卷 1256-1261页

作者： zhongli liu Quanyou Fang College of Biochemical Engineering Beijing Union University Beijing China

In this paper, a new two-step Newton-type method with third-order convergence for solving systems of nonlinear equations is proposed. We construct the new method based on the integral interpolation of Newton’s method. Its cubic convergence and error equation are proved theoretically, and demonstrated numerically. Its application to systems of nonlinear equations and boundary-value problems of nonlinear ODEs are shown as well in the numerical examples.

关键词： Newton-Type Method Systems of Nonlinear Equations Third-Order Convergence Integral Interpolation