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Bioactive sesquineolignans from the twigs of Litsea cubeba

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Chinese Journal of Natural Medicines 2021年第10期19卷 796-800页

作者： xia Huan xia gui-yang WANG Ling-Yan WANG Min WANG Ya-Nan LIN Peng-Cheng LIN Sheng Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing Dongzhimen HospitalBeijing University of Chinese MedicineBeijing 100700China 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 College of Pharmaceutical Sciences Qinghai University for NationalitiesXining 810000China

In a continuing search for biological natural products with structure diversity from traditional Chinese herbs,five new sesquineolignans(1−5)were isolated from an ethyl acetate extract of the twigs of Litsea *** structures were elucidated based on MS,1D and 2D NMR spectroscopic data,as well as experimental electronic circular dichroism(ECD)*** 1−5 showed moderate inhibitory effects against LPS-induced NO production in RAW264.7 macrophages,with IC50 values of 16.2,20.2,22.1,15.1,and 16.6μmol·L^(−1),respectively.

关键词： Litsea cubeba Sesquineolignans NO production inhibitory activity

Phenological Complementarity Does not Enhance Ecosystem Production in Undisturbed Steppe Community

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Journal of Integrative Plant Biology 2007年第5期49卷 582-587页

作者： Liang Zhao gui-xia yang Zhong-Ling Liu xiao-Ping Xin Yan-Jiang LUO Gang Wang Key Laboratory of Arid and Grassland Ecology at Lanzhou University Ministry of Education Lanzhou 730000 China Key Laboratory of Resources Remote Sensing and Digital Agriculture Ministry of Agriculture Beijing 100083 China Inner Mongolia University Huhhot 010021 China

Communities with more species could have a greater variety of species＇ characteristics, leading to more effective use of limiting resources through niche partitioning （complementarity） and therefore greater production. The effect of phenologlcal complementarity （PC） on ecosystem production has not been fully Investigated. The seasonal responses of all vascular plant species were tracked to test the effect of phenologlcal complementarity on ecosystem production within a natural stable steppe community. Although a significant phenologlcal pattern was observed, PC had no significant correlation with community production. The value of PC varied with years, but was observed only In a relatively narrow range during the experimental period. Species diversity （richness and evenness） had no correlation with the ecosystem production. The results suggest that the effect of PC may be saturated and has no contribution to the improvement of ecosystem production In a stable natural grassland community with abundant species.

关键词： ecosystem function phenological complementarity steppe community temporal variation total annual net primary productivity.

Bioactive neolignans and lignans from the roots of Paeonia lactiflora

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Chinese Journal of Natural Medicines 2022年第3期20卷 210-214页

作者： xia Huan ZHANG Jing-Fang WANG Ling-Yan xia gui-yang WANG Ya-Nan WU Yu-Zhuo LIN Peng-Cheng XIONG Liang LIN Sheng Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing Dongzhimen HospitalBeijing University of Chinese MedicineBeijing 100700China 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 College of Pharmaceutical Sciences Qinghai University for NationalitiesXining 810000China School of Pharmacy Chengdu University of Traditional Chinese MedicineChengdu 611137China

Two new neolignans and one new lignan(1-3)were obtained from the roots of Paeonia *** structures were unambiguously elucidated based on extensive spectroscopic analysis,single-crystal X-ray crystallography,and the calculated and experimental electronic circular dichroism(ECD)*** 1 was a racemic mixture and successfully resolved into the anticipated enantiomers via chiral-phase *** 3 demonstrated moderate inhibitory activity against human carboxylesterase 2A1(hCES2Al)with an IC_(50) value of 7.28±0.94 μmol·L^(-1).

关键词： Paeonia lactiflora Neolignan Lignan Human carboxylesterase 2A1

Voidage correction method for DEM study of 3D pebble flows in a bed of cycloidal base

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Particuology 2024年第10期93卷 30-40页

作者： Zirui xia Minglei Shi Quan Zou Nan gui Xingtuan yang Jiyuan Tu Shengyao Jiang Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and SafetyMinistry of EducationTsinghua UniversityBeijing100084China Department of Engineering Physics Tsinghua UniversityBeijing100084China Department of Automation Tsinghua UniversityBeijing100084China School of Engineering RMIT UniversityMelbourneVIC3083Australia

Voidage(porosity or void fraction)in packed particles(or pebbles)is of fundamental importance in calculating the pressure drop,obtaining the drag,predicting the bed permeability,estimating the neutron streaming,*** the case when particles are deformed,a method of voidage correction during the packing state is proposed using a Discrete Element Method(DEM)simulation of 3D pebble flow inside a bed of cycloidal base.A function to evaluate the remaining volume of a pebble intercepted by horizontal and vertical planes is proposed for voidage *** that,the process of solving voidage distribution is provided in *** this method,the voidage inside the cycloidal-base pebble bed is obtained to refer to reported similar data for *** method can be potentially used for dynamical voidage calculation in CFD-DEM simulation which can get suitable voidage distribution after the correction.

关键词： Voidage Pebbleflow Packed bed Discreteelementmethod Cycloidal base KD-Tree Volume correction

Three new polyoxygenated bergamotanes from the endophytic fungus Penicillium purpurogenum IMM 003 and their inhibitory activity against pancreatic lipase

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Chinese Journal of Natural Medicines 2020年第1期18卷 75-80页

作者： xia gui-yang WANG Ling-Yan ZHANG Jing-Fang WU Yu-Zhuo GE Guang-Bo WANG Ya-Nan LIN Peng-Cheng LIN Sheng State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 1Q0050China Institute of Interdisciplinaty Medicine Shanghai University of Traditional Chinese MedicineShanghai 201203China College of Pharmaceutical Sciences Qinghai University for NationalitiesXining 810000China

Purpurolides D–F(1–3),three new polyoxygenated bergamotanes bearing a 6/4/5/5 tetracyclic ring system,were isolated from the endophytic fungus Penicillium purpurogenum IMM *** structures were unambiguously elucidated based on extensive spectroscopic data analyses,13 C NMR chemical shifts calculations coupled with the DP4+probability method,and the calculated and experimental electronic circular dichroism(ECD)*** 1–3 showed significant inhibitory activity against pancreatic lipase(PL).The result highlights that the presence of 3-hydroxylated decanoic acid moiety at C-14 is important for increasing the inhibition potency against PL.

关键词： Penicillium purpurogenum Sesquiterpene lactones Pancreatic lipase inhibitors

Synthesis of a High-Efficiency Demulsifier and Study on Optimal Demulsification Conditions

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China Petroleum Processing & Petrochemical Technology 2024年第1期26卷 107-115页

作者： Zhu Shuai Zhang YingYu gui xia College of Chemical Engineering Nanjing Tech University30 Puzhunan RoadNanjing 211816China

Oil and water separation has always been a top priority in the oil *** this study,a series of hyperbranched fluorinated polyamine-amine polymers(HFPA1-5)were synthesized directly using an improved“one-pot method.”The highly active fluorinated p-trifluoromethylaniline was used as the core raw material,while diethylenetriamine and methyl acrylate were used as the chain segment.A hyperbranched fluorine-containing polyamine-amine demulsifier(NHFPA6)was obtained through nano-grafting copolymerization of *** enhance the demulsification and dehydration performance,the copolymerized HFPA6 was modified and ***,the effects of the combination ratio,demulsifier concentration,demulsification time,and demulsification temperature on the demulsification effect were *** results revealed that a combination ratio of DE-401:NHFPA6=1:1,a demulsification temperature of 50℃,a demulsification time of 60 min,and a demulsifier concentration of 150 mg/L yielded a dehydration rate as high as 99.80%.A response surface optimization design of demulsification conditions was *** model verified that the optimal demulsification conditions were 50℃,300 mg/L,and 90 ***,considering the economic benefits of factories,it is more favorable to select demulsification conditions with a shorter time and lower concentration when the dehydration standard is ***,the demulsification conditions were selected as 50℃,150 mg/L,and 60 *** to existing demulsifiers,the demulsifier developed in this study exhibits a lower demulsification temperature and higher demulsification efficiency.

关键词： hyperbranched fluorinated polyamine-amine nano-SiO_(2)

Formation Characteristics of CO_(2) Hydrates in the Presence of Porous Media and NaCl

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China Petroleum Processing & Petrochemical Technology 2024年第2期26卷 168-177页

作者： Han Jianchao Zhu Shuai gui xia College of Chemical Engineering Nanjing Tech UniversityNanjing 211816China

Hydrate-based CO_(2) sequestration is an effective method for reducing the greenhouse effect,and the presence of porous media and NaCl can impact the formation characteristics of *** study uses the constant volume temperature search method to investigate the effects of quartz sand particle size(0.006‒0.03 mm),water saturation(30%–90%),and NaCl concentration(1%‒9%)on the phase equilibrium and kinetics of CO_(2) hydrates within a temperature range of 273‒285 K and pressure range of 1.0‒3.5 *** results indicate that a decrease in quartz sand particle size or an increase in NaCl concentration shifts the hydrate phase equilibrium curve towards lower temperatures and higher pressures,making hydrate generation conditions more *** different particle size systems,there are no significant changes in the rate of CO_(2) hydrate formation or conversion *** highest hydrate conversion rate of 71.1%is observed in a 0.015 mm particle size *** increasing water saturation,both the generation rate and conversion rate of CO_(2) hydrates show a trend of first increasing and then ***,low concentrations of NaCl(1%–3%)are found to enhance the formation and conversion rates of CO_(2) ***,as NaCl concentration increases,the rate of CO_(2) hydrate formation and conversion rate decrease.

关键词： CO_(2)hydrate porous medium NaCl formation characteristics

Application of CFD and FEA Coupling to Predict Structural Dynamic Responses of A Trimaran in Uni-and Bi-Directional Waves

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China Ocean Engineering 2024年第1期38卷 81-92页

作者： LIAO Xi-yu xia Jin-song CHEN Zhan-yang TANG Qin ZHAO Nan ZHAO Wei-dong gui Hong-bin Marine Design&Research Institute of China Shanghai 200011China Ship Structure Division China Ship Scientific Research CenterWuxi 214082China College of Ocean Engineering Harbin Institute of TechnologyWeihaiWeihai 264209China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China School of Foreign Studies Jiangnan UniversityWuxi 214122China

To predict the wave loads of a flexible trimaran in different wave fields,a one-way interaction numerical simulation method is proposed by integrating the fluid solver(Star-CCM+)and structural solver(Abaqus).Differing from the existing coupled CFD-FEA method for monohull ships in head waves,the presented method equates the mass and stiffness of the whole ship to the hull shell so that any transverse and longitudinal section stress of the hull in oblique waves can be ***,verification study and sensitivity analysis are carried out by comparing the trimaran motions using different mesh sizes and time step *** on the wave elevation of uni-and bi-directional waves is also carried *** a comprehensive analysis on the structural responses of the trimaran in different uni-directional regular wave and bi-directional cross sea conditions is carried out,***,the differences in structural response characteristics of trimaran in different wave fields are *** results show that the present method can reduce the computational burden of the two-way fluid-structure interaction simulations.

关键词： CFD-FEA fluid-structure coupling structural responses trimaran bi-directional cross sea

Asynchronous Learning-Based Output Feedback Sliding Mode Control for Semi-Markov Jump Systems: A Descriptor Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1358-1369页

作者： Zheng Wu Yiyun Zhao Fanbiao Li Tao yang yang Shi Weihua gui School of Automation Central South UniversityChangsha 410083China Power Electronics Machines and Control GroupThe University of NottinghamNottingham NG72RDUK Department of Mechanical Engineering University of VictoriaVictoria BC V8W 3P6Canada IEEE

This paper presents an asynchronous output-feed-back control strategy of semi-Markovian systems via sliding mode-based learning *** with most literature results that require exact prior knowledge of system state and mode information,an asynchronous output-feedback sliding sur-face is adopted in the case of incompletely available state and non-synchronization *** holonomic dynamics of the sliding mode are characterized by a descriptor system in which the switching surface is regarded as the fast subsystem and the system dynamics are viewed as the slow *** upon the co-occurrence of two subsystems,the sufficient stochastic admissibility criterion of the holonomic dynamics is derived by utilizing the characteristics of cumulative distribution ***,a recursive learning controller is formulated to guarantee the reachability of the sliding manifold and realize the chattering reduction of the asynchronous switching and sliding ***,the proposed theoretical method is substantia-ted through two numerical simulations with the practical contin-uous stirred tank reactor and F-404 aircraft engine model,respectively.

关键词： Asynchronous switching learning-based control output feedback semi-Markovian jump systems sliding mode con-trol(SMC).