4,669 results on '"G.Y. Li"'
Search Results
2. Letter to the editor regarding "Misclassified confounders in the second interim analysis of the MAGNITUDE trial" by P. Chen, M. Liu, G.Y. Li, F. Sun, T. Li
- Author
-
Chi, K.N., primary
- Published
- 2023
- Full Text
- View/download PDF
3. New Biological Macromolecules Findings from G.Y. Li et al Outlined (Structural characterization and anti-thrombotic properties of fucoidan from Nemacystus decipiens)
- Subjects
Elsevier Science B.V. -- Reports ,Periodical publishing -- Analysis -- Reports -- Research ,Physical fitness -- Analysis -- Reports -- Research ,Marine sciences -- Analysis -- Reports -- Research ,Obesity ,Galactose ,Polysaccharides ,Sulfates ,Monosaccharides ,Editors ,Health - Abstract
2018 DEC 8 (NewsRx) -- By a News Reporter-Staff News Editor at Obesity, Fitness & Wellness Week -- Research findings on Life Science Research - Biological Macromolecules are discussed in [...]
- Published
- 2018
4. Findings on Chondroitin Sulfate Discussed by G.Y. Li and Co-Researchers (A novel structural fucosylated chondroitin sulfate from Holothuria Mexicana and its effects on growth factors binding and anticoagulation)
- Subjects
Physical fitness -- Reports ,Chondroitin -- Reports ,Sulfates -- Reports ,Anticoagulants -- Reports ,Health - Abstract
2018 JAN 20 (NewsRx) -- By a News Reporter-Staff News Editor at Obesity, Fitness & Wellness Week -- Investigators publish new report on Chondroitin Sulfate. According to news reporting originating [...]
- Published
- 2018
5. Recent Findings from G.Y. Li and Co-Authors Yields New Data on Peptide Hydrolases (High Expression of Human Cathepsin S by Recombinant Pichia pastoris with Cod Skin as an Organic Co-Nitrogen Source)
- Subjects
Glycerol -- Reports ,Peptides -- Reports ,Cathepsins -- Reports ,Skin -- Reports ,Biotechnology industry ,Pharmaceuticals and cosmetics industries - Abstract
2018 FEB 21 (NewsRx) -- By a News Reporter-Staff News Editor at Biotech Week -- Fresh data on Enzymes and Coenzymes - Peptide Hydrolases are presented in a new report. [...]
- Published
- 2018
6. Comparison of antioxidant enzyme activity and gene expression in two new spring wheat cultivars treated with salinity
- Author
-
Y.L. XU, Y. ZHANG, J.M. LI, T.P. GAO, L.N. ZHANG, L.B. SI, Q. LI, G.Y. LI, and Y.L. YANG
- Subjects
catalase ,diamineoxidase ,malondialdehyde ,nacl ,peroxidase ,polyamine oxidase ,superoxide dismutase ,triticum aestivum ,Biology (General) ,QH301-705.5 ,Plant ecology ,QK900-989 - Abstract
This study aimed to analyze element content, antioxidative response, and related gene expression in two new wheat (Tritium aestivum L.) cultivars Longchun 30 and Longchun 27 when exposed to different NaCl concentrations. Low NaCl concentration (25 mM) promoted root growth and decreased malondialdehyde (MDA) content and relative conductivity (REC) in Longchun 30. Differently, higher salinity stress (100 and 200 mM NaCl) inhibited root growth and increased MDA content and REC in both cultivars. Under salt stress, the increment of Na content in the roots and leaves and the reduction of Ca content in the roots were more remarkable in Longchun 27 than in Longchun 30. In contrast, the potassium content decreased in the roots but did not significantly change in the leaves in both cultivars under salinity. When the seedlings were exposed to salinity, the increases of superoxide dismutase (SOD) and catalase (CAT) activities in Longchun 27 roots were associated with high isoenzymes abundance and high TaCu/ZnSOD, TaMnSOD and TaCAT expression. Meanwhile, total peroxidase (POD) activity induced by NaCl treatment coincided with the changes of TaPOD expression and isoenzyme abundance in both cultivars. Besides, the inhibition of activities of apoplastic antioxidant enzymes, cell wall-bound POD, diamine oxidase, and polyamine oxidase was observed in salinity-stressed roots of both cultivars. Taken together, cv. Longchun 30 might be more suitable for growing in salinity environment in comparison with Longchun 27.
- Published
- 2021
- Full Text
- View/download PDF
7. New Geoscience Study Findings Have Been Reported by G.Y. Li and Colleagues (ZY-3 Block adjustment supported by glas laser altimetry data)
- Subjects
Health ,Science and technology - Abstract
2016 APR 29 (NewsRx) -- By a News Reporter-Staff News Editor at Science Letter -- Researchers detail new data in Science. According to news originating from Jiangsu, People's Republic of [...]
- Published
- 2016
8. Studies from G.Y. Li and Colleagues Provide New Data on Geoscience (Laboratory testing on heat transfer of frozen soil blocks used as backfills of pile foundation in permafrost along Qinghai-Tibet electrical transmission line)
- Subjects
Power lines ,Health ,Science and technology - Abstract
2015 JUN 26 (NewsRx) -- By a News Reporter-Staff News Editor at Science Letter -- Current study results on Science have been published. According to news reporting from Jining, People's [...]
- Published
- 2015
9. Studies in the Area of Apoptosis Reported from G.Y. Li and Co-Researchers
- Subjects
Apoptosis ,Angiotensin ,Health - Abstract
By a News Reporter-Staff News Editor at Health & Medicine Week -- Research findings on Apoptosis are discussed in a new report. According to news reporting originating in Hong Kong, [...]
- Published
- 2014
10. Findings on HIV/AIDS Reported by G.Y. Li et al
- Subjects
AIDS (Disease) -- Research ,Health - Abstract
By a News Reporter-Staff News Editor at AIDS Weekly -- Fresh data on Immune System Diseases and Conditions are presented in a new report. According to news reporting originating in [...]
- Published
- 2014
11. Report Summarizes Cyclohexanes Study Findings from G.Y. Li and Co-Researchers
- Subjects
Monoamine oxidase -- Reports ,Biological sciences ,Health ,American Chemical Society -- Reports - Abstract
By a News Reporter-Staff News Editor at Life Science Weekly -- Current study results on Cyclohexanes have been published. According to news originating from Montreal, Canada, by NewsRx correspondents, research [...]
- Published
- 2014
12. Findings on Clinical Trials and Studies Detailed by G.Y. Li and Co-Authors
- Subjects
Medical research ,Medicine, Experimental ,Clinical trials ,Health - Abstract
By a News Reporter-Staff News Editor at Clinical Trials Week -- Current study results on Research have been published. According to news reporting originating in Hong Kong, People's Republic of [...]
- Published
- 2013
13. Reports Outline Hematologic Agents Research from G.Y. Li and Colleagues
- Subjects
Biotechnology industry ,Pharmaceuticals and cosmetics industries - Abstract
According to the authors of recent research from Hangzhou, People's Republic of China, 'A novel glycosaminoglycan-like sulfated polysaccharide (AAP) from the pleopods of Haliotis discus hannai Ino was purified by [...]
- Published
- 2011
14. Findings in HIV/AIDS Reported from G.Y. Li and Co-Researchers
- Subjects
HIV (Viruses) -- Analysis ,AIDS (Disease) -- Analysis ,Health - Abstract
'Macrophages and CD4(+) lymphocytes are the major reservoirs for HIV-1 infection. CD63 is a tetraspanin transmembrane protein, which has been shown to play an essential role during HIV-1 replication in [...]
- Published
- 2011
15. Studies from G.Y. Li and Colleagues Reveal New Findings on Gram-Negative Bacteria
- Subjects
Gram-negative bacteria -- Research ,Health ,Science and technology - Abstract
According to recent research from Griffith, Australia, 'A bactericidal technique (PEC-Br) utilizing in situ photoelectrocatalytically generated photoholes (h(+)), long-lived di-bromide radical anions (Br-2(-)) and active oxygen species (AOS) for instant [...]
- Published
- 2011
16. Recent Findings in Edwardsiella Described by G.Y. Li and Colleagues
- Subjects
Health ,Science and technology - Abstract
In this recent study, researchers in Qingdao, People's Republic of China conducted a study 'To differentiate pathogenic and nonpathogenic Edwardsiella tarda strains based on the detection of type III secretion [...]
- Published
- 2011
17. New DNA research research from G.Y. Li and co-researchers described
- Subjects
DNA -- Research ,Genetic research ,Health ,Science and technology - Abstract
'Poly(ADP-ribosyl)ation by poly(ADP-ribose) polymerases regulates the interaction of many DNA damage and repair factors with sites of DNA strand lesions. The interaction of these factors with poly (ADP-ribose) (PAR) is [...]
- Published
- 2010
18. Comparison of antioxidant enzyme activity and gene expression in two new spring wheat cultivars treated with salinity
- Author
-
L.N. Zhang, Yingli Yang, Tianpeng Gao, G.Y. Li, Yaolei Zhang, Qiang Li, L.B. Si, Y.L. Xu, and J.M. Li
- Subjects
0106 biological sciences ,0301 basic medicine ,biology ,Chemistry ,food and beverages ,Plant Science ,Horticulture ,Malondialdehyde ,01 natural sciences ,Apoplast ,Enzyme assay ,Salinity ,Superoxide dismutase ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,Catalase ,biology.protein ,Diamine oxidase ,Polyamine oxidase ,010606 plant biology & botany - Abstract
This study aimed to analyze element content, antioxidative response, and related gene expression in two new wheat (Tritium aestivum L.) cultivars Longchun 30 and Longchun 27 when exposed to different NaCl concentrations. Low NaCl concentration (25 mM) promoted root growth and decreased malondialdehyde (MDA) content and relative conductivity (REC) in Longchun 30. Differently, higher salinity stress (100 and 200 mM NaCl) inhibited root growth and increased MDA content and REC in both cultivars. Under salt stress, the increment of Na content in the roots and leaves and the reduction of Ca content in the roots were more remarkable in Longchun 27 than in Longchun 30. In contrast, the potassium content decreased in the roots but did not significantly change in the leaves in both cultivars under salinity. When the seedlings were exposed to salinity, the increases of superoxide dismutase (SOD) and catalase (CAT) activities in Longchun 27 roots were associated with high isoenzymes abundance and high TaCu/ZnSOD, TaMnSOD and TaCAT expression. Meanwhile, total peroxidase (POD) activity induced by NaCl treatment coincided with the changes of TaPOD expression and isoenzyme abundance in both cultivars. Besides, the inhibition of activities of apoplastic antioxidant enzymes, cell wall-bound POD, diamine oxidase, and polyamine oxidase was observed in salinity-stressed roots of both cultivars. Taken together, cv. Longchun 30 might be more suitable for growing in salinity environment in comparison with Longchun 27.
- Published
- 2021
19. An integrated smoothed particle hydrodynamics method for numerical simulation of the droplet impacting with heat transfer
- Author
-
H.W. Xu, G.Y. Li, X.J. Ma, and B.W. Zhang
- Subjects
Materials science ,Computer simulation ,Applied Mathematics ,Flow (psychology) ,Surface force ,General Engineering ,Mechanics ,Deformation (meteorology) ,Physics::Fluid Dynamics ,Surface tension ,Smoothed-particle hydrodynamics ,Computational Mathematics ,Viscosity ,Heat transfer ,Analysis - Abstract
According to the complex flow dynamics of droplets impacting on the wall, an integrated smoothed particle hydrodynamics (SPH) method is developed by a series of improved techniques including artificial viscosity, kernel gradient correction (KGC) technique, boundary treatment and so on, combined with the surface tension based on the continuous surface force (CSF) model in this paper. This method is validated by simulations of the square cavity flow and natural variations of a square droplet, and effects of particle diameter, kernel function, and artificial viscosity coefficient are also analyzed. On this basis, dynamic behavior of the droplet impacting on the wall with heat transfer is studied, and the results agree well with the experimental results. It is observed that the wall characteristics have a significant influence on the droplet deformation, and the droplet tends to spread on the hydrophilic wall. In the investigated temperature difference, the influence of temperature difference could be ignored, but there is energy exchange between the droplet and the wall. In general, the spreading law of droplet is consistent with the physical phenomena, which shows that the integrated SPH method can effectively deal with engineering problems involving a droplet impacting on the wall with heat transfer.
- Published
- 2021
20. Genetic variations of EBV-LMP1 from nasopharyngeal carcinoma biopsies: potential loss of T cell epitopes
- Author
-
Y.L. Tang, J.H. Lu, L. Cao, M.H. Wu, S.P. Peng, H.D. Zhou, C. Huang, Y.X. Yang, Y.H. Zhou, Q. Chen, X.L. Li, M. Zhou, and G.Y. Li
- Subjects
Genetic variation ,Epitope ,Immune recognition ,Latent membrane protein 1 ,Tumorigenicity ,Medicine (General) ,R5-920 ,Biology (General) ,QH301-705.5 - Abstract
To find Epstein-Barr virus (EBV) strains with genetic variations of EBV latent membrane protein 1 (EBV-LMP1) from nasopharyngeal carcinoma (NPC), the full-length DNA of LMP1 genes from 21 NPC biopsies obtained in Hunan province in southern China was amplified and sequenced. Our sequences were compared to those previously reported by the Clustal V method. Results showed that all 21 sequences displayed two amino acid changes most frequently in LMP1 of CD4+ T cell epitopes at codons 144 (F®I, 21/21) and 212 (G®S, 19/21) or (G®N, 2/21). We also show that type A EBV strain is prevalent in the cases of NPC from Hunan province with a 30-bp 18/21 deletion, and we highlight that this deletion resulted in loss of one of the CD4+ T cell-restricted epitopes. The other 3 sequences without this deletion all had a change at codon 344 (G®D). Furthermore, in the major epitope sequence of CD8+ T cells restricted by HLA-A2, all 21 sequences showed changes at codons 126 (L®F) and 129 (M®I). Our study discovered that one of the 21 sequence variations harbored a new change at codon 131 (W®C), and 5/21 specimens showed another novel change at codon 115 (G®A) in the major epitope sequence of CD8+ T cells restricted by HLA-A2. Our study suggests that these sequence variations of NPC-derived LMP1 may lead to a potential escape from host cell immune recognition, protecting latent EBV infection and causing an increase in tumorigenicity.
- Published
- 2008
21. Tailoring microstructure and martensitic transformation of selective laser melted Ti49.1Ni50.9 alloy through electropulsing treatment
- Author
-
G.Y. Li, D. Chen, S. Wang, Y.X. Tong, Y.B. Jiang, and F.C. Jiang
- Subjects
Mechanics of Materials ,Materials Chemistry ,General Materials Science - Published
- 2022
22. Zr addition-dependent twin morphology evolution and strengthening response in nanostructured Al thin films
- Author
-
G.Y. Li, Daniel Kiener, Jun Sun, Jinyu Zhang, M. Zhang, Gang Liu, Xiaobin Feng, Y.Q. Wang, J.D. Zuo, Sophie Cazottes, C. He, Y. Lu, Junhua Luan, Los Alamos National Laboratory (LANL), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Morton K. Blaustein Department of Earth and Planetary Sciences [Baltimore], Johns Hopkins University (JHU), Laboratoire de Physico-Chimie des Surfaces (LPCS), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche de Chimie Paris (IRCP), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ministère de la Culture (MC), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-Catalytic and Atmospheric Reactivity for the Environment (CARE), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC)
- Subjects
010302 applied physics ,Materials science ,Morphology (linguistics) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,[SPI.MAT]Engineering Sciences [physics]/Materials ,Solid solution strengthening ,Stacking-fault energy ,Phase (matter) ,0103 physical sciences ,General Materials Science ,Grain boundary ,Composite material ,Thin film ,0210 nano-technology ,Crystal twinning ,Strengthening mechanisms of materials - Abstract
Manipulating the twin morphology to achieve the reinforcement of strength is a great challenge in Al with high stacking fault energy. In this work, the influence of Zr addition on the twin morphology and strengthening response of nanostructured Al films was symmetrically studied. The results showed that, for low Zr addition (≤ 4.0 at.%), the Zr atoms were homogeneously distributed within the matrix, while Zr segregation at grain boundaries was evident at higher Zr addition (> 4.0 at.%). Twins were substantially observed in all the films, and the twin morphology was highly dependent on the Zr addition. In the pure Al film, only twins with a single coherent twin boundary were detected. In comparison, nanotwins with coplanar twin boundaries (C-nanotwins) and 9R phase were predominant in the Al-Zr films with Zr addition ≤ 4.0 at.%. Further raising the Zr content, multiple nanotwins (M-nanotwins) coexisted with the C-nanotwins and 9R phase. In particular, a zero-strain twinning mechanism was applied to account for the C-nanotwins and 9R phase formation, and a zig-zag grain boundary feature induced by Zr segregation was responsible for the M-nanotwin formation. The hardness also exhibited a strong Zr dependence that increased monotonically with the Zr addition. The Al-13.4 at.% Zr film displayed a hardness of ~4.3 GPa, about 11 times greater than the pure Al film. Strengthening mechanisms were quantitatively evaluated, and the highly-promoted hardness was mainly ascribed to the 9R phase and solid solution strengthening.
- Published
- 2021
23. Analysis and optimization of clutch judder based on a hybrid uncertain model with random and interval variables
- Author
-
Y. Y. Huang, Eric Li, Zhicheng He, C. C. Lian, G.Y. Li, and Y. D. Hao
- Subjects
Control and Optimization ,Computer science ,Powertrain ,Applied Mathematics ,02 engineering and technology ,Interval (mathematics) ,Management Science and Operations Research ,01 natural sciences ,Industrial and Manufacturing Engineering ,Computer Science Applications ,Vibration ,Nonlinear system ,Noise ,020303 mechanical engineering & transports ,Harshness ,0203 mechanical engineering ,Control theory ,0103 physical sciences ,Clutch ,010301 acoustics ,Friction torque - Abstract
Clutch judder has serious impacts on the noise, vibration and harshness performance. In this article, a simplified dynamic model with nonlinear friction torque is developed to simulate clutch judde...
- Published
- 2018
24. Uncertainty analysis and optimization of automotive driveline torsional vibration with a driveline and rear axle coupled model
- Author
-
Y. D. Hao, G.Y. Li, Y. Y. Huang, Zhicheng He, and Eric Li
- Subjects
Control and Optimization ,Torsional vibration ,Computer science ,Powertrain ,Applied Mathematics ,Manual transmission ,Noise, vibration, and harshness ,02 engineering and technology ,Management Science and Operations Research ,01 natural sciences ,Industrial and Manufacturing Engineering ,Automotive engineering ,Computer Science Applications ,010101 applied mathematics ,Vibration ,Noise ,Axle ,020303 mechanical engineering & transports ,Harshness ,0203 mechanical engineering ,0101 mathematics - Abstract
The driveline torsional vibration issue is one of the most significant Noise, Vibration and Harshness (NVH) problems, especially in rear-wheel drive vehicles with manual transmission. In this artic...
- Published
- 2018
25. A high strength and high electrical conductivity CuCrZr alloy prepared by aging and subsequent cryorolling
- Author
-
G.Y. Li, J.D. Wang, Li Li, S.Y. Li, Dian-tao Zhang, and Yunxiang Tong
- Subjects
010302 applied physics ,Materials science ,Precipitation (chemistry) ,Alloy ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,01 natural sciences ,Surfaces, Coatings and Films ,Electrical resistivity and conductivity ,0103 physical sciences ,Ultimate tensile strength ,Mechanical strength ,engineering ,Composite material ,0210 nano-technology ,Crystal twinning ,Instrumentation - Abstract
In the present study, high strength and high electrical conductivity Cu-0.65Cr-0.07Zr (wt.%) was prepared by aging and subsequent cryorolling. The influence of processing on microstructure and properties of alloy were investigated. After aging, the fine and uniformly dispersed nano-precipitates appeared in the matrix. The cryorolled sample was characterized by a finer microstructure than the sample rolled at room temperature. The desired balance between the tensile strength of 712 MPa and electrical conductivity of 70.2% was obtained in the sample aged and cryorolled for 90% reduction. The combination of aging and subsequent cryorolling is effective in optimizing mechanical strength and electrical conductivity of CuCrZr alloy due to grain refinement, precipitation and twinning.
- Published
- 2021
26. Effect of dietary vitamin A supplementation on growth performance, nutrient digestibility, serum parameters and liver histology of growing-furring male mink kits (Neovison vison)
- Author
-
W.X. Nan, L.L. Mu, H.H. Zhang, H.Z. Si, Y.J. Lou, and G.Y. Li
- Subjects
Vitamin ,0303 health sciences ,Nutrient digestibility ,Dose ,030309 nutrition & dietetics ,0402 animal and dairy science ,04 agricultural and veterinary sciences ,Biology ,biology.organism_classification ,040201 dairy & animal science ,Neovison ,03 medical and health sciences ,chemistry.chemical_compound ,Animal science ,chemistry ,biology.animal ,medicine ,Animal Science and Zoology ,Dry matter ,Mink ,medicine.symptom ,Liver histology ,Weight gain - Abstract
This experiment was conducted to investigate the effects of supplemental vitamin A (VitA) on the growth performance, nutrient digestibility, serum biochemical parameters, and liver histology of growing-furring mink kits (Neovison vison). Ninety healthy male mink were randomly assigned to 6 treatment groups, with 15 mink per group. Each mink was housed in an individual cage. Mink in the 6 groups were fed diets supplemented with vitamin A acetate at dosages of 0 kIU/kg (VitA 0), 5 kIU/kg (VitA5), 20 kIU/kg (VitA20), 80 kIU/kg (VitA80), 320 kIU/kg (VitA320) or 1280 kIU/kg (VitA1280) of the basal diet. A 7-day pretest period preceded a formal test period of 60 days. The results showed that the final body weight (BW), average daily gain (ADG), weight gain (WG), average daily feed intake (ADFI) and the digestibility of dry matter (DM), crude protein (CP), ether extract (EE), and carbohydrate (CHO) exhibited a quadratic relationship (P
- Published
- 2021
27. Carbon fluxes and species diversity in grazed and fenced typical steppe grassland of Inner Mongolia, China
- Author
-
R. Sagar, J. S. Singh, G.Y. Li, and Shiqiang Wan
- Subjects
0106 biological sciences ,geography ,Biomass (ecology) ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Ecology ,Steppe ,Biodiversity ,Species diversity ,Plant Science ,010603 evolutionary biology ,01 natural sciences ,Grassland ,Carbon cycle ,Environmental science ,Ecosystem ,Species richness ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences - Published
- 2017
28. Predictive capability of a leaf optical meter for determining leaf pigment status during senescence
- Author
-
D.P. Aubrey, G.Y. Li, and H.Z. Sun
- Subjects
0106 biological sciences ,0301 basic medicine ,Absorption (pharmacology) ,Cornus alba ,Physiology ,macromolecular substances ,Plant Science ,Photosynthesis ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,Pigment ,Botany ,polycyclic compounds ,Carotenoid ,chemistry.chemical_classification ,biology ,fungi ,food and beverages ,Plant physiology ,biology.organism_classification ,030104 developmental biology ,chemistry ,Chlorophyll ,Anthocyanin ,visual_art ,visual_art.visual_art_medium ,sense organs ,010606 plant biology & botany - Abstract
We conducted an experiment to assess the predictive capability of a leaf optical meter for determining leaf pigment status of Acer mono Maxim., A. ginnala Maxim., Quercus mongolica Fisch., and Cornus alba displaying a range of visually different leaf colors during senescence. Concentrations of chlorophyll (Chl) a, Chl b, and total Chl [i.e., Chl (a+b)] decreased while the concentration of carotenoids (Car) remained relatively static for all species as leaf development continued from maturity to senescence. C. alba exhibited the lowest average concentration of Chl (a+b), Chl a, and Car, but the highest relative anthocyanin concentration, while Q. mongolica exhibited the highest Chl (a+b), Chl b, and the lowest relative anthocyanin concentration. A. mono exhibited the highest Chl a and Car concentrations. The relationships between leaf pigments and the values measured by the optical meter generally followed an exponential function. The strongest relationships between leaf pigments and optical measurements were for A. mono, A. ginnala, and Q. mongolica (R 2 ranged from 0.64 to 0.95), and the weakest relationships were for C. alba (R 2 ranged from 0.13 to 0.67). Moreover, optical measurements were more strongly related to Chl a than to Chl b or Chl (a+b). Optical measurements were not related to Car or relative anthocyanin concentrations. We predicted that weak relationships between leaf pigments and optical measurements would occur under very low Chl concentrations or under very high anthocyanin concentrations; however, these factors could not explain the weak relationship between Chl and optical measurements observed in C. alba. Overall, our results indicated that an optical meter can accurately estimate leaf pigment concentrations during leaf senescence — a time when pigment concentrations are dynamically changing — but that the accuracy of the estimate varies across species. Future research should investigate how species-specific leaf traits may influence the accuracy of pigment estimates derived from optical meters.
- Published
- 2017
29. Coupled-field simulation of electromagnetic tube forming process using a stable nodal integration method
- Author
-
Hui Feng, G.Y. Li, and Xiangyang Cui
- Subjects
Electromagnetic field ,0209 industrial biotechnology ,Mathematical optimization ,Engineering ,business.industry ,Mechanical Engineering ,02 engineering and technology ,Condensed Matter Physics ,Topology ,01 natural sciences ,Electromagnetic forming ,010101 applied mathematics ,020901 industrial engineering & automation ,Sequential coupling ,Mechanics of Materials ,Triangle mesh ,Smoothed finite element method ,General Materials Science ,Node (circuits) ,0101 mathematics ,Coefficient matrix ,business ,Smoothing ,ComputingMethodologies_COMPUTERGRAPHICS ,Civil and Structural Engineering - Abstract
This paper proposes a stable nodal integration method for analyzing coupling problems of electromagnetic field and mechanical field using linear triangular mesh. For transient electromagnetic field analysis, the node-based smoothed solution is firstly formulated to compute system matrices, and then the equivalent smoothing domain and temporal integration points are constructed to achieve a stable nodal integration method (SNIM), whose coefficient matrix is finally computed using the smoothed shape function derivatives together with the variance terms over the equivalent smoothing domain associated with nodes of the mesh. For dynamic large-deformation analysis, the node-based smoothed finite element method (NS-FEM) is utilized after testifying its stability and effectiveness in thin-walled structures of electromagnetic forming (EMF) process. Furthermore, by treating the morphing region as a static mechanical problem, a weighted elastomer method is presented to accomplish the mesh updating in sequential coupling simulation. Finally, it turns out that the proposed methodologies can be applied successfully to simulate EMF process, and numerical examples for both tube bulging and tube compression are investigated to demonstrate the validity, accuracy and efficiency of the proposed methods.
- Published
- 2017
30. An accurate and efficient scheme for acoustic-structure interaction problems based on unstructured mesh
- Author
-
Xiangyang Cui, Gang Wang, Xin Hu, and G.Y. Li
- Subjects
Discretization ,Mechanical Engineering ,Numerical analysis ,Coordinate system ,Computational Mechanics ,General Physics and Astronomy ,Geometry ,02 engineering and technology ,Topology ,01 natural sciences ,Finite element method ,Computer Science Applications ,010101 applied mathematics ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Computer Science::Sound ,Mechanics of Materials ,Tetrahedron ,Smoothed finite element method ,Boundary value problem ,0101 mathematics ,Smoothing ,Mathematics - Abstract
This paper focuses on the accurate and efficient numerical implementation of acoustic-structure coupling formulations using the edge-based smoothed finite element method for the flexible shell and the gradient-weighted finite element method for the acoustic fluid field, namely, the ES/GW-FEM. The shell is discretized using the simplest linear triangular elements and the edge-based smoothing domain is then constructed. By introducing an edge local coordinate system, the edge-based smoothing operation is performed on the smoothing domain. As for the acoustic fluid domain, the tetrahedron elements are adopted. A compacted support domain is then constructed and the gradient weighted operation is performed on the support domain. To model the exterior acoustic domain, an artificial boundary is introduced and the Dirichlet-to-Neumann (DtN) boundary condition is imposed. Based on the appropriate compatibility and equilibrium conditions on the interface boundaries, the coupled ES/GW-FEM formulation is finally obtained. Both the interior acoustic-structure coupled problems and exterior acoustic-structure coupled problems are available as the DtN boundary is considered. Numerical examples demonstrate that the coupled ES/GW-FEM achieves much higher accuracy and works more reliably compared with the coupled FEM/FEM in solving practical engineering problems.
- Published
- 2017
31. The performance prediction and optimization of the fiber-reinforced composite structure with uncertain parameters
- Author
-
G.Y. Li, Zhiwu Liang, Xiaobin Hu, and Xiangyang Cui
- Subjects
Cumulative distribution function ,Monte Carlo method ,Composite number ,Probability density function ,02 engineering and technology ,Fiber-reinforced composite ,01 natural sciences ,Finite element method ,010101 applied mathematics ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Control theory ,Ceramics and Composites ,Performance prediction ,0101 mathematics ,Smoothing ,Civil and Structural Engineering ,Mathematics - Abstract
The fiber-reinforced composites display the random fiber orientations and uncertain material parameters because of the manufacturing error and scattering feature. For this problem, the uncertain prediction and optimization based on the transformed perturbation stochastic method, the edged-based smoothing technique and the optimization theory is presented. In this method, the non-Gaussian probability density functions and the cumulative distribution functions of multi-variables for stochastic static responses of fiber-reinforced composite structure are explicitly exhibited as the prediction result compared with the Monte Carlo solution. Unlike the direct MCs, it only needs an iteration as the FEM and has the potential in the complex construction. In order to improve the efficiency and capability to resist the mesh distortion compared with the traditional stochastic FEM, the edged-based smoothing technique is introduced into the present framework. Furthermore, the stable performance feature of the fiber-reinforced composite in the uncertain working condition is presented. Consequently, objectives of the structural stability and insensitivity criteria based on the second-order perturbation expansion are proposed, and overall uncertain conditions coupled by uncertain fiber orientation, external load, material parameters and geometry sizes are analyzed and optimized within this framework, respectively. To verify the effectiveness and accuracy of the uncertain analysis and optimization in this study, three examples including the composite plates, the composite shell and the composite top cover of automobile are provided.
- Published
- 2017
32. Design of materials using hybrid cellular automata
- Author
-
J. H. Chen, G.Y. Li, Xiangyang Cui, and Daicong Da
- Subjects
Bulk modulus ,Mathematical optimization ,Control and Optimization ,Topology optimization ,02 engineering and technology ,Material Design ,01 natural sciences ,Computer Graphics and Computer-Aided Design ,Homogenization (chemistry) ,Cellular automaton ,Computer Science Applications ,010101 applied mathematics ,Shear modulus ,020303 mechanical engineering & transports ,Design objective ,0203 mechanical engineering ,Control and Systems Engineering ,0101 mathematics ,Engineering design process ,Software ,Mathematics - Abstract
This paper presents a new approach for the topological design of materials with extreme properties. The method is based on hybrid cellular automaton (HCA), which is an implicit optimization technique that uses local rules to update design variables iteratively until meeting the described optimality conditions. By means of an energy-based homogenization approach, the effective properties of the considered material are calculated in terms of element mutual energies. By this method, no sensitivity information is required to find the optimal topology for the considered design objectives: bulk modulus, shear modulus, and negative Poisson’s ratio. The proposed method is validated by a series of numerical examples.
- Published
- 2017
33. Concurrent topological design of composite structures and the underlying multi-phase materials
- Author
-
Xiangyang Cui, Kai Long, Daicong Da, and G.Y. Li
- Subjects
Materials science ,Concurrent engineering ,Multi phase ,Mechanical Engineering ,Composite number ,Topology optimization ,02 engineering and technology ,Microstructure ,Topology ,01 natural sciences ,Homogenization (chemistry) ,Finite element method ,Computer Science Applications ,010101 applied mathematics ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Modeling and Simulation ,General Materials Science ,0101 mathematics ,Material properties ,Civil and Structural Engineering - Abstract
This paper presents a concurrent topology optimization approach for simultaneous design of composite structures and their periodic material microstructures with three or more phases. The effective properties of multi-phase materials are obtained via homogenization technique which serves as a bridge of the finite element models of the macrostructure and the material microstructure. The base materials of periodic microstructures used in each phase of the macrostructure are divided into several groups and sensitivity analysis are carried out on them one by one. Meanwhile, the sensitivity number at the macrostructure is derived which is coupled with the designed material properties. Then, the composite configurations of material microstructures and macrostructures are inversely optimized concurrently based on the bi-directional evolutionary structural optimization (BESO) algorithm. Several 2D and 3D numerical examples are presented to demonstrate the effectiveness of proposed design approach.
- Published
- 2017
34. Strengthened antioxidant capacity improves photosynthesis by regulating stomatal aperture and ribulose-1,5-bisphosphate carboxylase/oxygenase activity
- Author
-
Chen Tingting, Yongzhi Zhou, G.Y. Li, W.M. Fu, Md. Tariqul Islam, Guanfu Fu, Feng Baohua, and Longxing Tao
- Subjects
0106 biological sciences ,0301 basic medicine ,Stomatal conductance ,Ribulose-Bisphosphate Carboxylase ,Plant Science ,Photosynthesis ,01 natural sciences ,Antioxidants ,03 medical and health sciences ,chemistry.chemical_compound ,Genetics ,Ribulose 1,5-bisphosphate ,biology ,fungi ,RuBisCO ,food and beverages ,Oryza ,General Medicine ,Ascorbic acid ,Pyruvate carboxylase ,Horticulture ,030104 developmental biology ,chemistry ,Catalase ,Plant Stomata ,biology.protein ,Photorespiration ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
ABA is important for plant growth and development; however, it also inhibits photosynthesis by regulating the stomatal aperture and ribulose-1,5-bisphosphate carboxylase/oxygenase activity. Noteworthy, this negative effect can be alleviated by antioxidants including ascorbic acid (AsA) and catalase (CAT), but the underlying mechanism remains unclear. Two rice cultivars, Zhefu802 (recurrent parent) and its near-isogenic line, fgl were selected and planted in a greenhouse with 30/24 °C (day/night) under natural sunlight conditions. Compared to fgl, Zhefu802 had significantly lower net photosynthetic rate (PN) and stomatal conductance (Cond) as well as significantly higher ABA and H2O2 contents. However, AsA and CAT increased PN, Cond, and stomatal aperture, which decreased H2O2 and malondialdehyde (MDA) levels. In this process, AsA and CAT significantly increased the ribulose-1,5-bisphosphate carboxylase activity, while they strongly decreased the ribulose-1,5-bisphosphate oxygenase activity, and finally caused an obvious decrease in the ratio of photorespiration (Pr) to PN. Additionally, AsA and CAT significantly increased the expression levels of RbcS and RbcL genes of leaves, while H2O2 significantly decreased them, especially the RbcS gene. In summary, the removal of H2O2 by AsA and CAT can improve the leaf photosynthesis by alleviating the inhibition on the stomatal conductance and ribulose-1,5-bisphosphate carboxylase capacity caused by ABA.
- Published
- 2019
35. A metamodel optimization methodology based on multi-level fuzzy clustering space reduction strategy and its applications
- Author
-
Wang, Hu, Li, Enying, G.Y., Li, and Z.H., Zhong
- Subjects
Server clustering ,Clustering (Computers) -- Usage ,Mathematical optimization -- Analysis - Abstract
This paper proposes metamodel optimization methodology based on multi-level fuzzy-clustering space reduction strategy with Kriging interpolation. The proposed methodology is composed of three levels. In the 1st level, the initial samples need partitioning into several clusters due to design variables by fuzzy-clustering method. Sequentially, only some of the clusters are involved in building metamodels locally in the 2nd level. Finally, the best optimized result is collected from all metamodels in the 3rd level. The nonlinear problems with multi-humps as test functions are implemented for proving accuracy and efficiency of proposed method. The practical nonlinear engineering problems are optimized by suggested methodology and satisfied results are also obtained. Keywords: Multi-level; Metamodel; Fuzzy clustering: Nonlinear; Kriging interpolation
- Published
- 2008
36. Acoustic simulation using a novel approach for reducing dispersion error
- Author
-
Xiangyang Cui, G.Y. Li, and Gang Wang
- Subjects
Discretization ,Helmholtz equation ,Applied Mathematics ,Mechanical Engineering ,Numerical analysis ,Mathematical analysis ,Computational Mechanics ,010103 numerical & computational mathematics ,01 natural sciences ,Domain (mathematical analysis) ,Finite element method ,Computer Science Applications ,010101 applied mathematics ,Mechanics of Materials ,Tetrahedron ,0101 mathematics ,Galerkin method ,Mathematics ,Interpolation - Abstract
Summary It is well-known that the traditional finite element method (FEM) fails to provide accurate results to the Helmholtz equation with the increase of wave number due to the “pollution error” caused by numerical dispersion. In order to overcome this deficiency, a gradient-weighted finite element method (GW-FEM) that combines Shepard interpolation and linear shape functions is proposed in this work. Three-node triangular and four-node tetrahedral elements that can be generated automatically are first used to discretize the problem domain in 2D and 3D spaces, respectively. For each independent element, a compacted support domain is then formed based on the element itself and its adjacent elements sharing common edges (or faces). With the aid of Shepard interpolation, a weighted acoustic gradient field is then formulated, which will be further used to construct the discretized system equations through the generalized Galerkin weakform. Numerical examples demonstrate that the present algorithm can significantly reduces the dispersion error in computational acoustics.
- Published
- 2016
37. A mass-redistributed finite element method (MR-FEM) for acoustic problems using triangular mesh
- Author
-
Eric Li, Gui-Rong Liu, A. G. Cheng, Zhicheng He, and G.Y. Li
- Subjects
Numerical Analysis ,Mathematical optimization ,Physics and Astronomy (miscellaneous) ,Discretization ,Applied Mathematics ,Numerical analysis ,02 engineering and technology ,Mixed finite element method ,Mass matrix ,01 natural sciences ,Finite element method ,Computer Science Applications ,010101 applied mathematics ,Computational Mathematics ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Mesh generation ,Modeling and Simulation ,Triangle mesh ,Applied mathematics ,0101 mathematics ,Conservation of mass ,Mathematics - Abstract
The accuracy of numerical results using standard finite element method (FEM) in acoustic problems will deteriorate with increasing frequency due to the "dispersion error". Such dispersion error depends on the balance between the "stiffness" and "mass" of discretization equation systems. This paper reports an improved finite element method (FEM) for solving acoustic problems by re-distributing the mass in the mass matrix to "tune" the balance, aiming to minimize the dispersion errors. This is done by shifting the integration point locations when computing the entries of the mass matrix, while ensuring the mass conservation. The new method is verified through the detailed numerical error analysis, and a strategy is also proposed for the best mass redistribution in terms of minimizing dispersion error. The relative dispersion error of present mass-redistributed finite element method (MR-FEM) is found to be much smaller than the FEM solution, in both theoretical prediction and numerical examination. The present MR-FEM works well by using the linear triangular elements that can be generated automatically, which enables automation in computation and saving computational cost in mesh generation. Numerical examples demonstrate the advantages of MR-FEM, in comparison with the standard FEM using the same triangular meshes and quadrilateral meshes.
- Published
- 2016
38. A novel hybrid ES-FE-SEA for mid-frequency prediction of Transmission losses in complex acoustic systems
- Author
-
Zhicheng He, F. Wu, Aiguo Cheng, G.Y. Li, and Gui-Rong Liu
- Subjects
Engineering ,Reverberation ,Acoustics and Ultrasonics ,business.industry ,Transmission loss ,Acoustics ,Structural engineering ,01 natural sciences ,Finite element method ,010101 applied mathematics ,Mid-frequency ,Robustness (computer science) ,Reciprocity (electromagnetism) ,Windshield ,0103 physical sciences ,0101 mathematics ,business ,010301 acoustics ,Statistical energy analysis - Abstract
The widely-used numerical modeling approaches such as the finite element method (FEM) and statistical energy analysis (SEA) often have limited applicability to the transmission loss prediction in mid-frequency range. In this paper, a novel hybrid edge-based smoothed FEM coupled with statistical energy analysis (ES-FE-SEA) method is proposed to further improve the accuracy of “mid-frequency” transmission loss predictions. The application of ES-FEM will “soften” the well-known ‘‘overly-stiff’’ behavior in the standard FEM solution and reduce the inherent numerical dispersion error. While the SEA approach deals with the physical uncertainty in the relatively higher frequency range. The plate of interest is appropriately described by an ES-FEM model, due to its relative robustness to perturbations. Its adjacent reverberation cavities are modeled by employing the SEA approach, because of their high model density. The coupling and interaction between SEA subsystems and the FE subsystem is governed by the “reciprocity relationship” theorem. A standard numerical example for benchmarking is examined and excellent agreement was achieved between the prediction and reference results. The proposed ES-FE-SEA is also verified by various numerical examples. The method is finally applied to the modeling a complicated engineering problem–acoustic fields on both sides of the front windshield in a passenger car.
- Published
- 2016
39. Stochastic analysis using the generalized perturbation stable node-based smoothed finite element method
- Author
-
H. Feng, Xiaobin Hu, Xiangyang Cui, and G.Y. Li
- Subjects
Random field ,Stochastic process ,Applied Mathematics ,Mathematical analysis ,Monte Carlo method ,General Engineering ,02 engineering and technology ,Mixed finite element method ,01 natural sciences ,Finite element method ,010101 applied mathematics ,Computational Mathematics ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Dynamic problem ,Applied mathematics ,Smoothed finite element method ,0101 mathematics ,Analysis ,Extended finite element method ,Mathematics - Abstract
The traditional stochastic finite element method based on the finite element method fails to give the fine solution in precise determination of reliable problems when the computer power consumption is limited. To cure this fatal defect, the generalized n th order stochastic perturbation technique based on a stable node-based smoothed finite element method (GS_SNS-FEM) is presented. The framework intends to essentially improve the accuracy, lower the mesh limitation and occupy much less computational consumption for stochastic problems, especially when its second order realization is ineffective for large variations of input random fields. Besides, the n th orders expansion makes it possible to get the prefect accuracy for expected values and variances. Numerical examples including the static and dynamic problems are completed and compared with the solution of Monte Carlo simulation. It is found that the SNS-FEM applied in the stochastic problem can improve the accuracy of static and dynamic results, largely decrease the time cost, and lower the requirement of mesh.
- Published
- 2016
40. Vegetative and Reproductive Growth and Yield of Plukenetia volubilis Plants in Responses to Foliar Application of Plant Growth Regulators
- Author
-
Z.Q. Cai, H.D. Gong, D.Y. Jiao, C. Yang, and G.Y. Li
- Subjects
0106 biological sciences ,0301 basic medicine ,Stomatal conductance ,Growing season ,Ripening ,Horticulture ,Biology ,biology.organism_classification ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,Abscission ,Agronomy ,chemistry ,Kinetin ,Plukenetia volubilis ,Abscisic acid ,Gibberellic acid ,010606 plant biology & botany - Abstract
Plukenetia volubilis Linneo, a tropical recurrent woody oilseed plant native to South America, was successfully introduced in China. A field experiment was conducted to determine the effect of the dry-season foliar sprays once every 2 weeks with 50 μm water or five different plant growth regulators (PGRs) viz., gibberellic acid (GA3), kinetin (KIN), indole-3-acetic acid (IAA), abscisic acid (ABA), and salicylic acid (SA) on the growth and yield of P. volubilis plants in Xishuangbanna, southwest China. Results showed that PGRs affected the leaf stomatal conductance (gS) and water-use efficiency (WUEi), rather than the net photosynthetic rate (PN). The phenological development of P. volubilis plants, including the time of flowering and maturity, and the dynamic pattern of fruit ripening, was not altered by PGR treatments. ABA and SA resulted in highest fruit set, seed oil content, and total fruit or seed oil yield, whereas GA3, IAA, and KIN were effective in increasing seed size. The nonstructural carbohydrates (NSC) are related to subsequent abscission or retention of the developing fruit, which was indicated by the positive relationship between carbohydrate concentration and fruit set across PGR treatments. The positive influences of PGRs on the total fruit yield (increased 4.3% to 15.2%) and total seed oil yield (increased 4.9% to 24.9%) per unit area throughout a growing season were found when compared with the control, depending to a great extent on the balance between vegetative and reproductive growth during the reproductive stage. This study suggests that PGRs, especially for ABA and SA, can become a valuable tool for promoting the seed oil yield of P. volubilis plants while maintaining high seed quality in the field.
- Published
- 2016
41. Accurate analysis and thickness optimization of tailor rolled blanks based on isogeometric analysis
- Author
-
Chensen Ding, G.Y. Li, and Xiangyang Cui
- Subjects
Engineering ,Control and Optimization ,business.industry ,Computation ,02 engineering and technology ,Structural engineering ,Isogeometric analysis ,01 natural sciences ,Computer Graphics and Computer-Aided Design ,Displacement (vector) ,Field (computer science) ,Computer Science Applications ,010101 applied mathematics ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Control and Systems Engineering ,Shape optimization ,Development (differential geometry) ,0101 mathematics ,business ,Engineering design process ,Algorithm ,Software ,Reliability (statistics) - Abstract
Combined isogeometric analysis (IGA) and shape optimization, this paper provides a method that can accurately analyze Tailor Rolled Blanks (TRB) and optimize its thickness profile continuously. While existed traditional methods can hardly solve these problems. TRB has a continuous transition between the thick and thin and a better surface quality. We found in IGA, two-dimension NURBS could present TRB geometry model exactly, but Kirchhoff shell element whose control points are allocated different thicknesses could not simulate TRB effectively. So, this paper uses three-dimension NURBS element to exactly present and accurately analyze TRB. It could avoid error caused by inaccurate presentation of geometry model and decrease error caused by solution field (displacement) approximation in numerical computation. Meanwhile, the positions of control points are taken as design variables in process of optimizing thickness profile. It can avoid the appearance of "unrealistic" shape and save lots of time spent in traditional tediously mesh updating as well as having better accuracy. This method makes accurate analysis and continuous thickness optimization of TRB become possible. It pushes the development of TRB engineering and extends the applications of IGA optimization. Several examples including benchmarks and application used the proposed method verified its effectivity, reliability and efficiency.
- Published
- 2016
42. A nodal integration axisymmetric thin shell model using linear interpolation
- Author
-
Gang Wang, Xiangyang Cui, and G.Y. Li
- Subjects
Applied Mathematics ,Numerical analysis ,Mathematical analysis ,02 engineering and technology ,Linear interpolation ,Curvature ,01 natural sciences ,Finite element method ,010101 applied mathematics ,Nonlinear system ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Modeling and Simulation ,Tensor ,0101 mathematics ,Galerkin method ,Smoothing ,Mathematics - Abstract
This paper proposed a nodal integration model for elasto-static, free vibration, forced vibration and geometric nonlinear analyses of axisymmetric thin shells using two-node truncated conical elements. The formulation is based on the Kirchhoff–Love theory, in which only the two translational displacements are treated as the independent field variables. A gradient smoothing technique (GST) is employed to relax the continuity requirement for trial function, so that linear shape functions can be used to interpolate both the tangent and normal displacement fields to the meridian. Based on each node, the integration domains are further formed, where the membrane strains and curvature changes are computed using a strain smoothing operation incorporated with a tensor transformation manipulation. The smoothed Galerkin weakform is then used to establish the discretized system equations. In order to accurately track the deformation path in geometric nonlinear analysis, the Newton–Raphson iteration in conjunction with the arc-length technique are employed here to solve the equilibrium equation. Numerical examples demonstrate that the present method can achieves higher accuracy and lower computing cost compared with the conventional finite element model.
- Published
- 2016
43. A stable nodal integration method with strain gradient for static and dynamic analysis of solid mechanics
- Author
-
H. Feng, Xiangyang Cui, and G.Y. Li
- Subjects
Mathematical optimization ,Applied Mathematics ,Numerical analysis ,Mathematical analysis ,General Engineering ,02 engineering and technology ,01 natural sciences ,Potential energy ,Finite element method ,010101 applied mathematics ,Computational Mathematics ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Dynamic problem ,Solid mechanics ,Displacement field ,Smoothed finite element method ,0101 mathematics ,Analysis ,Smoothing ,Mathematics - Abstract
A stable nodal integration method with strain gradient (SNIM-SG) for curing the temporal instability of node-based smoothed finite element method (NS-FEM) is proposed for dynamic problems using linear triangular and tetrahedron element. In each smoothing domain, except for considering the smoothed strain into the calculation of potential energy functional as NS-FEM, a term related to strain gradient is taken into account as a stabilization term. The proposed SNIM-SG can achieve appropriate system stiffness in strain energy between FEM and NS-FEM solutions and obtains quite favorable results in elastic and dynamic analysis. The accuracy and stability of SNIM-SG solution are studied through detailed analyzes of benchmark cases and practical engineering problems. In elastic-static analysis, it is found that SNIM-SG can provide higher accuracy in displacement field than the reference approaches do. In free vibration analysis, the spurious non-zero energy modes can be eliminated effectively owing to the fact that SNIM-SG solution strengths the original relatively soft NS-FEM, and SNIM-SG is confirmed to obtain fairly accurate natural frequency values in various examples. All in all, SNIM-SG cures the flaws of NS-FEM and enhances the dominant of nodal integration. Thus, the efficacy of the presented formulation in solving solid mechanics problems is well represented and clarified.
- Published
- 2016
44. A coupled smoothed finite element method (S-FEM) for structural-acoustic analysis of shells
- Author
-
Xiangyang Cui, G.Y. Li, Z.M. Liang, and Gang Wang
- Subjects
Diffuse element method ,Applied Mathematics ,Numerical analysis ,General Engineering ,Shell (structure) ,Geometry ,Finite element method ,Computational Mathematics ,Smoothed finite element method ,Meshfree methods ,Galerkin method ,Analysis ,Smoothing ,Mathematics - Abstract
In this paper, a coupled smoothed finite element method (S-FEM) is developed to deal with the structural-acoustic problems consisting of a shell configuration interacting with the fluid medium. Three-node triangular elements and four-node tetrahedral elements that can be generated automatically for any complicated geometries are adopted to discretize the problem domain. A gradient smoothing technique (GST) is introduced to perform the strain smoothing operation. The discretized system equations are obtained using the smoothed Galerkin weakform, and the numerical integration is applied over the further formed edge-based and face-based smoothing domains, respectively. To extend the edge-based smoothing operation from plate structure to shell structure, an edge coordinate system is defined local on the edges of the triangular element. Numerical examples of a cylinder cavity attached to a flexible shell and an automobile passenger compartment have been conducted to illustrate the effectiveness and accuracy of the coupled S-FEM for structural-acoustic problems.
- Published
- 2015
45. A stable node-based smoothed finite element method for acoustic problems
- Author
-
H. Feng, G.Y. Li, Gang Wang, and Xiangyang Cui
- Subjects
Helmholtz equation ,Mechanical Engineering ,Numerical analysis ,Mathematical analysis ,Computational Mechanics ,General Physics and Astronomy ,Mixed finite element method ,Stability (probability) ,Computer Science Applications ,Mechanics of Materials ,Smoothed finite element method ,Node (circuits) ,Smoothing ,Mathematics ,Stiffness matrix - Abstract
It is well-known that the classical “overly-soft” node-based smoothed finite element method (NS-FEM) fails to provide reliable results to the Helmholtz equation due to the “temporal instability”. To cure the fatal drawback of NS-FEM and reduce the dispersion error in computational acoustics, this paper proposed a stable node-based smoothed finite element method (SNS-FEM) for analyzing acoustic problems using linear triangular (for 2D space) and tetrahedral (for 3D space) elements that can be generated automatically for any complicated configurations. In the present formulation, the system stiffness matrix is computed using the smoothed acoustic pressure gradients together with the gradient variance items over the smoothing domains associated with nodes of element mesh. It turns out the addition of stabilization term makes the SNS-FEM possess an ideal stiffness, thus successfully cures the temporal instability and significantly reduces the dispersion error in acoustic problems. Numerical examples, including both benchmark cases and practical engineering problems, demonstrate that the SNS-FEM possesses the following important properties: (1) temporal stability; (2) super accuracy and super convergence; (3) higher computational efficiency; (4) insensitive to mesh distortion.
- Published
- 2015
46. Acoustic simulation using α-FEM with a general approach for reducing dispersion error
- Author
-
Eric Li, G. R. Liu, Zhicheng He, G.Y. Li, X. Nie, and F. Wu
- Subjects
Mathematical optimization ,Applied Mathematics ,Numerical analysis ,General Engineering ,Finite element method ,Discrete system ,Computational Mathematics ,Matrix (mathematics) ,Computer Science::Sound ,Solid mechanics ,Applied mathematics ,Smoothed finite element method ,Boundary value problem ,Analysis ,Smoothing ,Mathematics - Abstract
The alpha finite element method (α-FEM) developed recently has showed outstanding features in solving solid mechanics and acoustic problems. In the α-FEM, a parameter alpha has been introduced to make the best use of “over-stiffness” of the FEM model and “over-softness” of the NS-FEM model to achieve the ultimate performance. Because the parameter alpha varies with the problems and the mesh size, it is difficult to find a general approach to determine, which holds back the application of the α-FEM method. In this paper, acoustic simulation using α-FEM with a general approach for reducing dispersion error is proposed. We first carry out a theoretical analysis of dispersion error, leading to a very important relation between the dispersion error and the parameter alpha. Next, the parameter of alpha is then determined by minimizing the dispersion error. The determined parameter alpha enables a proper gradient smoothing operation in the α-FEM, and provides a perfect balance between the stiffness and mass in the discrete system matrix, which dramatically reduces the dispersion error. The properties of the present α-FEM have been confirmed numerically via examples of 1D, 2D and 3D acoustic problems with various boundary conditions.
- Published
- 2015
47. New insights from analysis of historical texts on the 1568 Northeast Xi'an earthquake, Shaanxi, China
- Author
-
X.N. Li, G.Y. Li, J. Ma, and X.J. Feng
- Subjects
021110 strategic, defence & security studies ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Semi-major axis ,0211 other engineering and technologies ,Magnitude (mathematics) ,Geology ,02 engineering and technology ,Fault (geology) ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,Epicenter ,China ,Ground shaking ,Safety Research ,Seismology ,0105 earth and related environmental sciences - Abstract
A destructive earthquake occurred in Northeast Xi'an, Shaanxi province, on May 25th, 1568 AD, causing many casualties, severe damage to property, and significant disruption to livelihoods. This earthquake has been chosen as a plausible basis for calculating a seismic scenario for the modern city of Weinan, and its surrounding urban areas. Previous studies agreed in assigning a magnitude 6 ¾ to the earthquake but yielded differing epicentral locations and isoseismal intensity maps. We combine textual research on historical earthquake reports with field investigations to reduce the uncertainties, and to place constraints on the ground shaking that would be experienced if such an earthquake were to recur. We show that the counties of Jingyang, Gaoling, and Xianning were the worst hit by the earthquake, with the townships of Yongle, Huijun, Pisha, and Fengzheng (present-day Gaozhuang and Zhangbu township), likely being in the mesoseismal area of this earthquake. Reinterpretation of the historical texts, combined with field observations, indicates that the epicenter of the earthquake was at about 34°28′N and 108°59′E, with an epicentral intensity of Ⅸ+ and an estimated magnitude of 7. The isoseismal contours have major axes-oriented WNW-ESE, in contrast to the more NS alignment inferred from the earlier study of the historical documents. The isoseismal of intensity VIII+encloses, and has its major axis parallel to, the active Weinan-Jingyang fault, which we infer to be the fault that slipped in the May 25th, 1568 earthquake.
- Published
- 2020
48. Analysis of the causative fault of the M~7 earthquake in the northeast part of Xi'an, China in the year 1568
- Author
-
J. Ren, C.Y. Yang, G.Y. Li, M. Li, X.N. Li, Y.Q. Shi, Jian Ma, Yi Zhang, X.J. Feng, and C.X. Li
- Subjects
021110 strategic, defence & security studies ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Exploration geophysics ,Paleozoic ,0211 other engineering and technologies ,Geology ,Subsidence ,02 engineering and technology ,Building and Construction ,Fault (geology) ,Structural basin ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,Quaternary ,Safety Research ,Cenozoic ,Seismology ,Holocene ,0105 earth and related environmental sciences - Abstract
The Weinan-Jingyang fault is one of the southern boundary faults of the Gushi secondary depression of the Weihe Basin, China. Geophysical exploration work and field geological surveys have demonstrated that this fault system has a length of approximately 105 km, and extends at least 5 km into the subsurface, with a northerly dip that shallows with depth. Under the influence of long-term displacement on the fault zone, the strata on the north side of the fault within the fault zone dip to the south, and the subsidence centre of the Gushi depression has migrated continuously southward. The Cenozoic activity of the Weinan-Jingyang fault has resulted in a significant dislocation between Paleozoic and Cenozoic strata on either side of the fault. This fault has been active during the Quaternary, especially the late Quaternary, in some places offsetting strata formed during the Ming Dynasty(1368–1644 CE), suggesting that this fault can reliably be regarded being active during Holocene time. Comprehensive re-examination of historical earthquake records, combined with field studies, confirm that the Weinan-Jingyang fault is likely the fault that slipped during a magnitude ~7 earthquake in northeast Xi'an, China in 1568 CE. That earthquake is here re-named the Shaanxi Gaoling Earthquake.
- Published
- 2020
49. WITHDRAWN: Analysis of the causative fault of the M~7 earthquake in the northeast part of Xi’an, China in the year 1568
- Author
-
X.J. Feng, J. Ma, G.Y. Li, X.N. Li, J. Ren, Y.Q. Shi, M. Li, Y. Zhang, C.X. Li, and C.Y. Yang
- Subjects
Geology ,Geotechnical Engineering and Engineering Geology ,Safety Research - Published
- 2018
50. Over-expression of MEOX2 promotes apoptosis through inhibiting the PI3K/Akt pathway in laryngeal cancer cells
- Author
-
Z.F. Zhan, H.P. Ye, H.W. Tuo, Z.Z. Tao, L. Tian, and G.Y. Li
- Subjects
0301 basic medicine ,Cancer Research ,Mesenchyme ,Apoptosis ,Biology ,03 medical and health sciences ,Phosphatidylinositol 3-Kinases ,Cell Line, Tumor ,medicine ,Humans ,Viability assay ,Protein kinase B ,Laryngeal Neoplasms ,PI3K/AKT/mTOR pathway ,Cell Proliferation ,Homeodomain Proteins ,Cancer ,medicine.disease ,XIAP ,030104 developmental biology ,medicine.anatomical_structure ,Oncology ,Cancer cell ,Cancer research ,Neoplasm Recurrence, Local ,Proto-Oncogene Proteins c-akt ,Signal Transduction - Abstract
The early-stage diagnosis and treatment for the recurrence of larynx carcinoma needs further investigation. Mesenchyme homeobox 2 (MEOX2) was speculated as a novel suppressor gene in larynx carcinoma in our study, the molecular mechanism was studied. Real-time quantitative PCR (RT-qPCR) and Western blot were used to detect mRNA and protein levels of MEOX2 in laryngeal cancer tissues and cells (Hep-2, TU212, AMC-NH-8 and TU686 cells), and also apoptosis and phosphoinositide 3-kinase (PI3K)/protein kinase (Akt) related factors in TU212 cells transfected with MEOX2. Cell counting kit-8 (CCK8) assay and Annexin-Ⅴ/PI staining assay were conducted to determine cell viability and apoptosis rates respectively.46 patients with larynx carcinoma were involved in this study. The expression of MEOX2 was lower in larynx carcinoma tissues than normal tissues, correlated with clinical stages, differentiated degrees, and survival times. The expression of MEOX2 was the lowest among those laryngeal cancer cells, and was chosen to be transfected with MEOX2 in the following study. Over-expression of MEOX2 inhibited cell viability and promoted apoptosis of TU212 cells, via increasing the expression levels of Caspase-3, and decreasing levels of C-Myc, XIAP, PI3K p110α, PI3K p110β, PI3K class III and p-Akt. In summary, the expression levels of MEOX2 were inhibited in larynx carcinoma than normal tissues, correlated with the progression of the cancer. Over-expression of MEOX2 in laryngeal cancer cells inhibited cell viability and promoted apoptosis, via regulating apoptosis and PI3K/Akt pathway related factors. It would provide evidence for MEOX2 to be used as a therapeutical gene in larynx carcinoma.
- Published
- 2017
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.