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Highly accurate symplectic element based on two variational principles

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Acta Mechanica Sinica 2018年第1期34卷 151-161页

作者： Guanghui Qing jia Tian College of Aeronautical Engineering Civil Aviation University of China

For the stability requirement of numerical resultants, the mathematical theory of classical mixed methods are relatively complex. However, generalized mixed methods are automatically stable, and their building process is simple and straightforward. In this paper, based on the seminal idea of the generalized mixed methods, a simple, stable, and highly accurate 8-node noncompatible symplectic element(NCSE8) was developed by the combination of the modified Hellinger-Reissner mixed variational principle and the minimum energy principle. To ensure the accuracy of in-plane stress results, a simultaneous equation approach was also suggested. Numerical experimentation shows that the accuracy of stress results of NCSE8 are nearly the same as that of displacement methods, and they are in good agreement with the exact solutions when the mesh is relatively fine. NCSE8 has advantages of the clearing concept, easy calculation by a finite element computer program, higher accuracy and wide applicability for various linear elasticity compressible and nearly incompressible material problems. It is possible that NCSE8 becomes even more advantageous for the fracture problems due to its better accuracy of stresses.

关键词： Modified H-R mixed variational principle Partial-mixed element Noncompatible symplectic element Finite element method Nearly incompressible material

Anti-polyphenol oxidase mechanism of oligomeric procyanidins and its application on browning control of“Baiyu”loquat during storage

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Food Bioscience 2022年第4期48卷 398-405页

作者： Gui-Li Huang Tian-Tian Liu jia-jia Ma Ling-Xiang Sun Si-Yao Sui Xin-Yao Quan Yu-Ning wang Agricultural Product Storage and Processing Laboratory Suzhou Academy of Agricultural SciencesSuzhou215105China Key Laboratory of Carbohydrate Chemistry and Biotechnology Science Center for Future FoodsJiangnan UniversityWuxi214122China jiangsu Key Laboratory for Biomass Energy and Material Institute of Chemical Industry of Forest Products CAFNanjing210042China

The harvested loquat fruits are prone to browning,leading to a decline in fruit *** activity of polyphenol oxidase(PPO)is an important way to prevent *** this study,we evaluated the inhibitory impact of oligomeric procyanidins(OPC)on hydroxylation of monophenol and oxidation of o-diphenol catalyzed by PPO and effect of OPC on loquat fruits *** obtained results revealed that OPC could attenuate the activity of monophenolase and *** monophenolase activity,the inhibition rate was observed to be dose-dependent with an IC50 of 11.6±3.4μg/mL for the steady-state *** diphenolase activity,OPC inhibited PPO activity(IC50=15.75±2.1μg/mL)with a reversible and competitive mechanism and quenched fluorescence of PPO by forming OPC-PPO complex with one binding site in a static *** addition,the data obtained from storage assays revealed that OPC could enhance the quality of harvested loquat fruits by attenuating the PPO activity,augmenting the content of total phenolics and flavonoids,and simultaneously delaying the browning of *** this research,we identified a potent PPO inhibitor and expanded its potential as a food preservative.

关键词： Polyphenol oxidase Oligomeric procyanidins Inhibitory mechanism Fluorescence quenching Storage

Numerical Study of the Unsteady Aerodynamics of Freely Falling Plates

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Communications in Computational Physics 2008年第4期3卷 834-851页

作者： Changqiu Jin kun Xu Institute of Applied Physics and Computational Mathematics P.O.Box 8009Beijing 100088China Mathematics Department Hong Kong University of Science and TechnologyHong KongChina.

The aerodynamics of freely falling objects is one of the most interesting flow mechanics *** a recent study,Andersen,Pesavento,and wang[*** Mech.,vol.541,pp.65-90(2005)]presented the quantitative comparison between the experimental measurement and numerical *** rich dynamical behavior,such as fluttering and tumbling motion,was ***,obvious discrepancies between the experimental measurement and numerical simulations still *** the current study,a similar numerical computation will be conducted using a newly developed unified coordinate gas-kinetic method[***,vol.222,pp.155-175(2007)].In order to clarify some early conclusions,both elliptic and rectangular falling plates will be *** the experimental condition,the numerical solution shows that the averaged translational velocity for both rectangular and elliptical plates are almost identical during the tumbling ***,the plate rotation depends strongly on the shape of the *** this study,the details of fluid forces and torques on the plates and plates movement trajectories will be presented and compared with the experimental measurements.

关键词： Navier-Stokes equations unified coordinate method unsteady aerodynamics falling plate.

Large-scale population structure and genetic architecture of agronomic traits of garlic

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Horticulture Research 2023年第4期10卷 187-199页

作者： Huixia jia Qing Zhao jiangping Song Xiaohui Zhang Wenlong Yang Zhenzhen Du Yue Zhu Haiping wang State Key Laboratory of Vegetable Biobreeding Institute of Vegetables and FlowersChinese Academy of Agricultural SciencesBeijing 100081China

Garlic,an asexually propagated crop,is the second important bulb crop after the onion and is used as a vegetable and medicinal *** and diverse garlic resources have been formed over thousands of years of ***,genome variation,population structure and genetic architecture of garlic agronomic traits were still not well ***,1100258 single nucleotide polymorphisms(SNPs)were identified using genotyping-by-sequencing in 606 garlic accessions collected from43 *** structure,principal component and phylogenetic analysis showed that these accessions were divided into five *** agronomic traits,including above-ground growth traits,bulb-related and bolt-related traits in two consecutive years were implemented in a genome-wide association *** total,542 SNPs were associated with these agronomic traits,among which 188 SNPs were repeatedly associated with more than two *** SNP(chr6:1896135972)was repeatedly associated with ten *** associated SNPs were located within or near 858 genes,56 of which were transcription ***,one non-synonymous SNP(Chr4:166524085)in ribosomal protein S5 was repeatedly associated with above-ground growth and bulb-related ***,gene ontology enrichment analysis of candidate genes for genomic selection regions between complete-bolting and non-bolting accessions showed that these genes were significantly enriched in‘vegetative to reproductive phase transition of meristem’,‘shoot system development’,‘reproductive process’,*** results provide valuable information for the reliable and efficient selection of candidate genes to achieve garlic genetic improvement and superior varieties.

关键词： agronomic traits repeatedly

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边缘恢复的大尺寸平面零件测量方法

红外与激光工程 2018年第4期47卷 47-55页

作者：李晓捷王佳耿磊叶琨天津工业大学计算机科学与软件学院天津300387 天津市光电检测技术与系统重点实验室天津300387 天津工业大学电子与信息工程学院天津300387

针对平面零件在背光源照射下成像存在伪边缘而造成测量精度下降的问题,提出了一种从被测物伪边缘中恢复准确边缘的测量方法。首先,采用Canny算子提取平面零件的像素边缘,在此基础上利用高斯曲面拟合算法实现亚像素边缘定位,得到伪边缘;... 详细信息

针对平面零件在背光源照射下成像存在伪边缘而造成测量精度下降的问题,提出了一种从被测物伪边缘中恢复准确边缘的测量方法。首先,采用Canny算子提取平面零件的像素边缘,在此基础上利用高斯曲面拟合算法实现亚像素边缘定位,得到伪边缘;然后,提出一种基于方向角差值的边缘点判别法从伪边缘中区分上下边缘点并提出欧氏距离平均值法获得被测物上边缘;最后,利用相似三角形法将上边缘转换到测量平面,结合摄像机标定参数求解平面零件的尺寸。实验结果表明,在1 200 mm×800 mm的视野范围内,对不同厚度的平面零件进行尺寸测量,绝对误差小于0.08 mm,相对误差小于0.05%。

关键词：尺寸测量大尺寸平面零件伪边缘欧氏距离相似三角形法

Numerical investigation of the interaction between upstream cavity purge flow and main flow in low aspect ratio turbine cascade

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Chinese Journal of Aeronautics 2013年第1期26卷 85-93页

作者： jia Wei Liu Huoxing National Key Laboratory of Science and Technology on Aero-Engines Aero-Thermodynamics School of Energy and Power Engineering Beihang University

In modern gas turbines, rim seal located between the stator-disc and rotor-disc is used to prevent hot-gas ingestion into the inner stage-gap of high pressure turbine. However, the purge flow supplied to the cavity through the rim seal interacts with the main flow, producing additional aerodynamic loss due to the mixing process which plays a significant role in the formation, development and evolution of downstream secondary flow. In this paper, a set of cascade representative of low aspect ratio turbine is selected to numerically investigate the influence of upstream cavity purge flow on the hub secondary flow structure and aerodynamic loss. Cascade with/without upstream cavity and four different purge mass flow rates are all taken into account in this simulation. Then, a deep insight into the loss mechanism of interaction between purge flow and main flow is gained. The results show that the presence of cavity and purge flow has a significant impact on the main flow which not only changes the vortex structure in both the passage and upstream cavity, but also alters the cascade exit flow angle distribution along the spanwise. Moreover, aerodynamic loss in the cascade rises with the increase of purge flow rate while the sealing effect is also enhanced. Therefore, the effect of upstream cavity purge flow must be considered in the process of turbine aerodynamic design. What is more, it is necessary to minimize the purge flow rate in order to reduce aerodynamic loss on the premise of satisfying cooling requirements.

关键词： Aerodynamic loss Low aspect ratio Purge flow Turbine Upstream cavity

Therapy of replenishing Yin and regulating Yang for manic episode in bipolar disorder:study protocol for a prospective,double-blind,randomized controlled trial

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Journal of Traditional Chinese Medicine 2023年第3期43卷 594-601页

作者： YANG Yang YUAN Haining jia Hongxiao NING Yanzhe wang Di ZHANG Lei YAN Kaijuan GUO Yumeng wang Fei SUN Weishuang CHEN Pei Beijing Key Laboratory of Mental Disorders National Clinical Research Center for Mental Disorders and National Center for Mental DisordersDepartment of integrated traditional Chinese and Western medicineBeijing Anding HospitalCapital Medical UniversityBeijingChina Advanced Innovation Center for Human Brain Protection Capital Medical UniversityBeijing 100088China Beijing Key Laboratory of Mental Disorders National Clinical Research Center for Mental Disorders and National Center for Mental DisordersBeijing Anding HospitalCapital Medical UniversityBeijing 100088China Advanced Innovation Center for Human Brain Protection Capital Medical UniversityBeijing 100069China

Bipolar disorder(BD) is a chronic and recurrent disorder characterized by biphasic mood episodes of mania or hypomania and *** affects more than 1% of the global population and is a leading cause of disability in young *** available treatments for BD are still fairly limited in terms of efficacy,with high rates of non-adherence,non-response,and undesirable side *** Chinese medicine(TCM) has a long history and rich experience in stabilizing mania and improving quality of *** at rebalancing Yin and Yang in BD,therapy of replenishing Yin and regulating Yang(RYRY therapy) has been in clinical use for years in *** present prospective,double-blind,randomized controlled trial is designed to investigate the efficacy and safety of RYRY therapy for bipolar mania and its possible mechanism from the point of regulating gut microbiota and anti-inflammation.A total of 60 eligible participants will be recruited from Beijing Anding *** will be randomized to either the study group or the control group in a ratio of 1∶*** allocated to the study group will receive RYRY granule,while placebo granule will be applied in the control *** in both groups will be prescribed conventional therapy for manic episode in *** scheduled visits will be conducted over 4 *** measurements include Young Mania Rating Scale,TCM Symptom Pattern Rating Scale,Treatment Emergent Symptom Scale,levels of C-reactive protein,interleukin-6 and tumor necrosis factor-α and the gut microbial community profile of stool *** outcomes and adverse events will also be *** this study,we set a number of scientific and objective assessments to evaluate the efficacy of RYRY therapy and study into its possible mechanism,hopefully offering clinicians an alternative approach to BD.

关键词： bipolar disorder replenishing Yin and regulating Yang gastrointestinal microbiome inflammation clinical protocol

Tradeoffs and synergies between ecosystem services : A comparison of the karst and non-karst area

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Journal of Mountain Science 2020年第5期17卷 1221-1234页

作者： HAN Hui-qing LIU Yue GAO Hong-juan ZHANG Ying-jia wang Zhe CHEN Xiao-qiao College of Architecture and Urban Planning Guizhou Institute of TechnologyGuiyang 550003China School of Geography and Resources Guizhou Education UniversityGuiyang 550018China

Under the influence of various natural and human factors, the relationship between the ecosystem services provided for human beings by a karst ecosystem is becoming increasingly complex, profoundly limiting the effective and sustainable development of the social economy and ecosystem protection in karst areas. Taking Guizhou, China as an example, which includes both karst(including five different landforms) and non-karst area, the study explored and compared the tradeoff and synergy between ecosystem services in both terrain types. The results showed higher change rates of water yield and soil retention in karst areas than those in non-karst areas, with only small differences in the carbon storage and crop production change. The ecosystem service relationships in the karst area from 1995 to 2005 were consistent with the relationships in the non-karst area. However, differences were observed in most of these relationships from 2005 to 2015. The relationships between ecosystem services in different karst landforms from 1995 to 2005 remained the same, but there are differences found in the relationships of ecosystem services from 2005 to 2015. The trade-off and synergistic relationships between ecosystem services in the different landforms were closely related to the changes of climate and land use, particularly related to rainfall, rainfall erosivity, farmland, and forestland.

关键词： Ecosystem service Tradeoff and synergy Spatial pattern Karst area Guizhou

Modelling of Non-Newtonian Starved Thermal-elastohydrodynamic Lubrication of Heterogeneous Materials in Impact Motion

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Acta Mechanica Solida Sinica 2021年第6期34卷 954-976页

作者： Xueyu Bai Qingbing Dong Han Zheng kun Zhou School of Mechanical and Aerospace Engineering Nanyang Technological University50 Nanyang AvenueSingapore639798Singapore State Key Laboratory of Mechanical Transmission Chongqing UniversityChongqing400030China College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing400030China Environmental Process Modelling Centre Nanyang Environment and Water Research InstituteNanyang Technological University1 Cleantech LoopSingapore637141Singapore

This study presents a numerical model for the thermal-elastohydrodynamic lubrication of heterogeneous materials in impact motion,in which a rigid ball bounces on a starved non-Newtonian oil-covered plane surface of an elastic semi-infinite heterogeneous solid with inhomogeneous *** impact–rebound process and the microscopic response of the subsurface inhomogeneous inclusions are *** inclusions are homogenized according to Eshelby’s equivalent inclusion *** Elrod algorithm is adopted to determine the lubrication starvation based on the solutions of pressure and film thickness,while the lubricant velocity and shear rate of the non-Newtonian lubricant are derived by using the separation flow *** dynamic response of the cases subjected to constant impact mass,momentum,and energy is discussed to reveal the influence of the initial drop height on the impact–rebound *** results imply that the inclusion disturbs the subsurface stress field and affects the dynamic response of the contact system when the surface pressure is *** impact energy is the decisive factor for the stress peak,maximum hydrodynamic force,and restitution coefficient,while the dynamic response during the early approaching process is controlled by the drop height.

关键词： Thermal-elastohydrodynamic lubrication Impact motion Lubrication starvation Non-Newtonian behaviour Inhomogeneous inclusion