18 results on '"Yang, Zhijian"'
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2. Optimal attractors of the Kirchhoff wave model with structural nonlinear damping.
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Li, Yanan and Yang, Zhijian
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CRITICAL exponents , *STRUCTURAL optimization , *NAVIER-Stokes equations , *ATTRACTORS (Mathematics) - Abstract
The paper investigates the well-posedness and longtime dynamics of the Kirchhoff wave model with structural nonlinear damping: u t t − ϕ (‖ ∇ u ‖ 2) Δ u + σ (‖ ∇ u ‖ 2) (− Δ) θ u t + f (u) = g (x) , with θ ∈ [ 1 / 2 , 1). We find a new critical exponent p ⁎ ≡ N + 2 N − 2 (> p θ ≡ N + 2 θ N − 2 , N ≥ 3) and show that when the growth exponent p of the nonlinearity f (u) is up to the range: 1 ≤ p < p ⁎ : (i) the IBVP of the equation is well-posed and its solution is of additionally global regularity when t > 0 ; (ii) for each θ ∈ [ 1 / 2 , 1) , the related solution semigroup has in natural energy space H an optimal global attractor A θ whose compactness and attractiveness are in the regularized space H 1 + θ where A θ lies, and an optimal exponential attractor E θ ⁎ whose compactness, boundedness of the fractional dimension and the exponential attractiveness are in H 1 + θ where E θ ⁎ lies, respectively; (iii) the family of global attractors { A θ } θ ∈ [ 1 / 2 , 1) is upper semi-continuous at each point θ 0 ∈ [ 1 / 2 , 1). The paper breaks though the longstanding existed growth restriction: 1 ≤ p ≤ p θ for p θ had been considered a uniqueness index, deepens and extends the results in literature [6,25,27]. [ABSTRACT FROM AUTHOR]
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- 2020
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3. Continuity of the attractors in time-dependent spaces and applications.
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Li, Yanan and Yang, Zhijian
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- 2023
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4. Stability of attractors for the Kirchhoff wave equation with strong damping and critical nonlinearities.
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Yang, Zhijian and Da, Fang
- Abstract
Abstract The paper investigates longtime dynamics of the Kirchhoff wave equation with strong damping and critical nonlinearities: u t t − (1 + ϵ ‖ ∇ u ‖ 2) Δ u − Δ u t + h (u t) + g (u) = f (x) , with ϵ ∈ [ 0 , 1 ]. The well-posedness and the existence of global and exponential attractors are established, and the stability of the attractors on the perturbation parameter ϵ is proved for the IBVP of the equation provided that both nonlinearities h (s) and g (s) are of critical growth. [ABSTRACT FROM AUTHOR]
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- 2019
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5. Stability of exponential attractors for a family of semilinear wave equations with gentle dissipation.
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Yang, Zhijian and Liu, Zhiming
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SEMILINEAR elliptic equations , *ENERGY dissipation , *EXPONENTIAL functions , *PERTURBATION theory , *ATTRACTORS (Mathematics) - Abstract
The paper investigates the stability of exponential attractors for a family of semilinear wave equations with gentle dissipation: u t t − Δ u + γ ( − Δ ) α u t + f ( u ) = g ( x ) , with α ∈ ( 0 , 1 / 2 ) . (i) We propose a new criterion on the existence and stability of a family of exponential attractors depending on the perturbation parameters. (ii) By applying this criterion to the equations, we construct a family of exponential attractors A e x p α and show their stability on the dissipative exponent α . [ABSTRACT FROM AUTHOR]
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- 2018
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6. Global attractor of the quasi-linear wave equation with strong damping.
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Yang, Zhijian and Liu, Zhiming
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QUASILINEARIZATION , *EXISTENCE theorems , *WAVE equation , *DYNAMICAL systems , *STABILITY theory - Abstract
The paper investigates the existence of global attractor of the quasi-linear wave equation with strong damping u t t − γ Δ u t − Δ u + f ( u ) = ∇ ⋅ ϕ ′ ( ∇ u ) + g . It proves that the energy solution of the equation is stable and the related dynamical system possesses a (strong) global attractor in natural energy space (rather than a weak one as known before). These results improve the recent ones in [13] . [ABSTRACT FROM AUTHOR]
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- 2018
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7. Longtime dynamics of the Kirchhoff equations with fractional damping and supercritical nonlinearity.
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Yang, Zhijian, Ding, Pengyan, and Li, Lei
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KIRCHHOFF'S theory of diffraction , *DAMPING (Mechanics) , *NONLINEAR analysis , *PARABOLIC differential equations , *MATHEMATICAL analysis - Abstract
The paper investigates the global well-posedness and the longtime dynamics of the Kirchhoff equations with fractional damping and supercritical nonlinearity: u t t − M ( ‖ ∇ u ‖ 2 ) Δ u + ( − Δ ) α u t + f ( u ) = g ( x ) , with α ∈ ( 1 2 , 1 ) . The main results are focussed on the relationships among the growth exponent p of the nonlinearity f ( u ) , the global well-posedness and the longtime dynamics of the equations. We show that (i) even if p is up to the supercritical range, that is, 1 ≤ p < N + 4 α ( N − 4 α ) + , the well-posedness and the longtime behavior of the solutions of the equation are of the characters of the parabolic equation; (ii) when N + 4 α ( N − 4 α ) + ≤ p < N + 4 ( N − 4 ) + , the corresponding subclass G of the limit solutions exists and possesses a weak global attractor. [ABSTRACT FROM AUTHOR]
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- 2016
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8. Attractors and their continuity for an extensible beam equation with rotational inertia and nonlocal energy damping.
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Sun, Yue and Yang, Zhijian
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- 2022
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9. Longtime dynamics of the Kirchhoff equation with strong damping and critical nonlinearity on [formula omitted].
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Yang, Zhijian and Ding, Pengyan
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KIRCHHOFF'S approximation , *NONLINEAR theories , *DAMPING (Mechanics) , *EXISTENCE theorems , *ATTRACTORS (Mathematics) , *CAUCHY problem - Abstract
The paper studies the longtime dynamics of the Kirchhoff equation with strong damping and critical nonlinearity on R N : u t t − Δ u t − M ( ‖ ∇ u ‖ 2 ) Δ u + u t + g ( x , u ) = f ( x ) . We establish the well-posedness, the existence of the global and exponential attractors in natural energy space H = H 1 ( R N ) × L 2 ( R N ) in critical nonlinearity case. These results improve not only the recent ones achieved by Yang (2007) [32] , but also ones achieved by Conti, Pata and Squassina (2005) [9] to some extent. [ABSTRACT FROM AUTHOR]
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- 2016
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10. Longtime behavior for an extensible beam equation with rotational inertia and structural nonlinear damping.
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Ding, Pengyan and Yang, Zhijian
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The paper investigates the well-posedness, regularity and longtime behavior of solutions for an extensible beam equation with fractional rotational inertia and structural nonlinear damping: (1 + (− Δ) θ) u t t + Δ 2 u − M (‖ ∇ u ‖ 2) Δ u + N (‖ ∇ u ‖ 2) (− Δ) α u t + f (u) = g , with dissipative index α ∈ (0 , 1 ] and rotational index θ ∈ [ 0 , α). We find a new critical exponent p θ α ≡ N + 2 (2 α − θ) (N − 4) + (> p ⁎ = N (N − 4) + ) depending on both θ and α and show that when the growth exponent p of the nonlinearity f (u) is up to the range: 1 ≤ p < p θ α , the well-posedness, regularity and longtime behavior of the solutions are like parabolic, in the concrete, (i) the IBVP of the equation admits a unique strong solution while its initial data is in weaker energy space; (ii) the related solution semigroup has a strong global attractor and a strong exponential attractor for each θ ∈ [ 0 , α) , where the "strong" means that the compactness, the attractiveness and the finiteness of the fractal dimension of the attractors are all in the topology of the strong solution space; (iii) the family of strong global attractors { A θ } θ ∈ [ 0 , α) is upper-semicontinuous on the perturbed index θ at any point θ 0 ∈ [ 0 , α). These results improve and extend those in recent literatures [17,24]. [ABSTRACT FROM AUTHOR]
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- 2021
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11. Applications of generative adversarial networks in neuroimaging and clinical neuroscience.
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Wang, Rongguang, Bashyam, Vishnu, Yang, Zhijian, Yu, Fanyang, Tassopoulou, Vasiliki, Chintapalli, Sai Spandana, Skampardoni, Ioanna, Sreepada, Lasya P., Sahoo, Dushyant, Nikita, Konstantina, Abdulkadir, Ahmed, Wen, Junhao, and Davatzikos, Christos
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GENERATIVE adversarial networks , *CLINICAL decision support systems , *CLINICAL neurosciences , *DEEP learning , *BRAIN tumors , *ALZHEIMER'S disease - Abstract
• A review of the adoption of generative adversarial networks in clinical neuroimaging. • We focus on GAN's applications in modeling disease effects of neurologic diseases. • We discuss the pitfalls of current studies and provide future perspectives. Generative adversarial networks (GANs) are one powerful type of deep learning models that have been successfully utilized in numerous fields. They belong to the broader family of generative methods, which learn to generate realistic data with a probabilistic model by learning distributions from real samples. In the clinical context, GANs have shown enhanced capabilities in capturing spatially complex, nonlinear, and potentially subtle disease effects compared to traditional generative methods. This review critically appraises the existing literature on the applications of GANs in imaging studies of various neurological conditions, including Alzheimer's disease, brain tumors, brain aging, and multiple sclerosis. We provide an intuitive explanation of various GAN methods for each application and further discuss the main challenges, open questions, and promising future directions of leveraging GANs in neuroimaging. We aim to bridge the gap between advanced deep learning methods and neurology research by highlighting how GANs can be leveraged to support clinical decision making and contribute to a better understanding of the structural and functional patterns of brain diseases. [Display omitted] [ABSTRACT FROM AUTHOR]
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- 2023
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12. MiR-654-3p, reduced by the excessive ALKBH5, Alleviated the Inflammation in OA by targeting TNFRSF9, the trigger of the NF-κB pathway.
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Yu, Baoxi, Zeng, Anyu, Liu, Hailong, Yang, Zhijian, and Fu, Ming
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DIOXYGENASES , *BINDING site assay , *RNA-binding proteins , *TUMOR necrosis factor receptors , *INFLAMMATION , *CARTILAGE cells - Abstract
MicroRNA (miRNA) is one of the most potent therapeutic targets for osteoarthritis (OA). We identified that miR-654-3p protected the phenotype of chondrocytes. We demonstrated that TNF receptor superfamily member 9 (TNFRSF9) was the target of miR-654-3p by binding to its 3′UTR regions, based on a dual-luciferase reporter assay and an RNA binding protein immunoprecipitation (RIP) assay. In addition, further experiments proved that TNFRSF9, as a trigger of the NF-κB pathway, correlated with the inflammation in chondrocytes. MiR-654-3p overexpressed in the knee of mice alleviated the OA in vivo. Moreover, we examined the m6A enzyme level in OA, proving that the abnormal expression of α-ketoglutarate-dependent dioxygenase alkB homolog 5 (ALKBH5) contributed to the miR-654-3p decrease. Our research illustrated the significant role of miR-654-3p in OA, including its maturation and the mechanism in protecting the phenotype of chondrocytes, which could be a new treatment target for OA. • miR-654-3p decreased the inflammation in OA by targeting TNFRSF9 directly. • TNFRSF9 activated the NF-κB Pathway in OA which could be suppressed by CD137 protein. • Excessive ALKBH5 limited the maturation of miR-654-3p. [ABSTRACT FROM AUTHOR]
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- 2022
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13. Brain-wide genome-wide colocalization study for integrating genetics, transcriptomics and brain morphometry in Alzheimer's disease.
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Bao, Jingxuan, Wen, Junhao, Wen, Zixuan, Yang, Shu, Cui, Yuhan, Yang, Zhijian, Erus, Guray, Saykin, Andrew J., Long, Qi, Davatzikos, Christos, and Shen, Li
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ALZHEIMER'S disease , *LOCUS (Genetics) , *GENETICS , *GENOME-wide association studies , *DRUG discovery , *CIS-regulatory elements (Genetics) - Abstract
Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. However, the AD mechanism has not yet been fully elucidated to date, hindering the development of effective therapies. In our work, we perform a brain imaging genomics study to link genetics, single-cell gene expression data, tissue-specific gene expression data, brain imaging-derived volumetric endophenotypes, and disease diagnosis to discover potential underlying neurobiological pathways for AD. To do so, we perform brain-wide genome-wide colocalization analyses to integrate multidimensional imaging genomic biobank data. Specifically, we use (1) the individual-level imputed genotyping data and magnetic resonance imaging (MRI) data from the UK Biobank, (2) the summary statistics of the genome-wide association study (GWAS) from multiple European ancestry cohorts, and (3) the tissue-specific cis-expression quantitative trait loci (cis-eQTL) summary statistics from the GTEx project. We apply a Bayes factor colocalization framework and mediation analysis to these multi-modal imaging genomic data. As a result, we derive the brain regional level GWAS summary statistics for 145 brain regions with 482,831 single nucleotide polymorphisms (SNPs) followed by posthoc functional annotations. Our analysis yields the discovery of a potential AD causal pathway from a systems biology perspective: the SNP chr10:124165615:G>A (rs6585827) mutation upregulates the expression of BTBD16 gene in oligodendrocytes, a specialized glial cells, in the brain cortex, leading to a reduced risk of volumetric loss in the entorhinal cortex, resulting in the protective effect on AD. We substantiate our findings with multiple evidence from existing imaging, genetic and genomic studies in AD literature. Our study connects genetics, molecular and cellular signatures, regional brain morphologic endophenotypes, and AD diagnosis, providing new insights into the mechanistic understanding of the disease. Our findings can provide valuable guidance for subsequent therapeutic target identification and drug discovery in AD. [ABSTRACT FROM AUTHOR]
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- 2023
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14. Role of electron injection on vertical leakage in GaN-on-Si epitaxial layers.
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Song, Chunyan, Yang, Xuelin, Ji, Panfeng, Tang, Jun, Hu, Anqi, Feng, Yuxia, Lin, Wei, Ge, Weikun, Yang, Zhijian, Xu, Fujun, and Shen, Bo
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EPITAXIAL layers , *ELECTRONS , *BUFFER layers , *ACTIVATION energy , *ELECTRIC fields , *LEAKAGE - Abstract
Abstract The impact of electron injection on vertical leakage current of GaN-on-Si epitaxial layers with an AlN interlayer has been investigated. At high electric field, the AlN interlayer as an energy barrier can suppress the injection of electrons from the silicon substrate into the top buffer layers, and eventually a vertical leakage was reduced by two orders of magnitude at 600 V. At low electric field, the holes flow via dislocations, and prevent the formation of a negative depletion region at the top GaN layer increasing the leakage. The correlation between the vertical leakage and the buffer-related trapping has also been clarified by ramped back-gating characterizations. Highlights • The vertical leakage was reduced by two orders of magnitude at 600 V with an AlN interlayer. • At high electric field, the results indicate that the electron injection plays a key role on vertical leakage. • At low field, the hole flowing via dislocations could increase the leakage for sample with an AlN interlayer. • The buffer related trapping effect is suppressed by inserting an AlN interlayer. [ABSTRACT FROM AUTHOR]
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- 2019
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15. Long-time behavior of a class of thermoelastic plates with nonlinear strain.
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Fatori, L.H., Jorge Silva, M.A., Ma, T.F., and Yang, Zhijian
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LAPLACIAN operator , *THERMOELASTICITY , *NONLINEAR analysis , *STRAINS & stresses (Mechanics) , *EXPONENTIAL stability - Abstract
In recent years a class of vibrating plates with nonlinear strain of p -Laplacian type was studied by several authors. The present paper contains a first thermoelastic model of that class of problems including both Fourier and non-Fourier heat laws. Our main result establishes the existence of global and exponential attractors for the strongly damped problem through a stabilizability inequality. In addition, for the weakly damped problem, we establish the exponential stability of its Galerkin semiflows. [ABSTRACT FROM AUTHOR]
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- 2015
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16. Puerarin improves cardiac function through regulation of energy metabolism in Streptozotocin-Nicotinamide induced diabetic mice after myocardial infarction.
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Cheng, Weili, Wu, Peng, Du, Yingqiang, Wang, Yunle, Zhou, Ningtian, Ge, Yingbin, and Yang, Zhijian
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HEART function tests , *ENERGY metabolism , *STREPTOZOTOCIN , *NICOTINAMIDE , *PEOPLE with diabetes , *THERAPEUTICS ,MYOCARDIAL infarction diagnosis - Abstract
It is well recognized that the incidence of heart failure and the risk of death is high in diabetic patients after myocardial infarction (MI). Accumulating evidence showed that puerarin (PUE) has protecting function on both cardiovascular disease and diabetes. The aim of this study is to explore whether puerarin could improve cardiac function in diabetic mice after MI and the underlying mechanism. The left anterior of Streptozotocin (STZ)-Nicotinamide (NA) induced diabetic mice were ligated permanently except for the Shame group. Then the operated mice were randomly treated with PUE or saline. Cardiac function was evaluated by echocardiograph before and at 1, 2, 4 weeks after MI. GLUT4/CD36/p-Akt/PPAR α of the heart was examined after treatment for 4 weeks. The results indicated that PUE significantly increased survival rate, improved cardiac function compared with MI group. Moreover, PUE increased expression and translocation of GLUT4 while attenuated expression and translocation of CD36. Western blot analysis showed that PUE enhanced phosphorylation of Akt and decreased PPAR α. This study demonstrated that PUE improved cardiac function after MI in diabetic mice through regulation of energy metabolism, the possible mechanism responsible for the effect of PUE was increasing the expression and translocation of GLUT4 while attenuating the expression and translocation of CD36. [ABSTRACT FROM AUTHOR]
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- 2015
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17. High-precision U-series dating of the late Pleistocene – early Holocene rock paintings at Tiger Leaping Gorge, Jinsha River valley, southwestern China.
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Wu, Yun, Jiao, Yanuo, Ji, Xueping, Taçon, Paul S.C., Yang, Zhijian, He, Siqi, Jin, Mangu, Li, Yinghua, and Shao, Qingfeng
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ROCK paintings , *HOLOCENE Epoch , *PLEISTOCENE Epoch , *ROCK art (Archaeology) , *GEOLOGICAL time scales - Abstract
Paleolithic rock paintings are known from many parts of the world, including Africa, Australia, Europe and Island Southeast Asia. However, no Paleolithic rock paintings have yet been confirmed in the East Asia mainland, partly due to the lack of suitable dating materials. The rock paintings distributed at more than 70 sites in the Jinsha River valley, Yunnan Province, southwestern China, include the naturalistic outlines of large mammals, which superficially resemble the Magdalenian rock art in Europe. Wanrendong Cave in Tiger Leaping Gorge, has preserved typical Jinsha River rock paintings, associated with some precipitates of secondary carbonates (i.e., speleothem). High precision U-series dating of 13 small speleothems, with a total of 36 subsamples overlying or underlying the pigment layers, revealed that these red paintings were created during the Pleistocene – Holocene transition, representing the oldest absolutely dated rock paintings from China so far. Our results show that at least three painting phases in Wanrendong Cave can be precisely constrained: ∼13,000–13,580 yr B.P., ∼10,540–10,830 yr B.P., and ∼8370–8700 yr B.P. These intervals are substantially earlier than the timing of agriculture in Yunnan Province (∼4600 yr BP), indicating that these paintings were created by Paleolithic hunter-gatherers. Additionally, these intervals coincide with the Bølling-Allerød and early Holocene warming periods, suggesting a possible link between the rock painting activity and climate changes. • High-precision U-series dating was applied to the speleothems associated with the rock paintings in Wanrendong Cave. • Wanrendong rock paintings were dated to three phases: 1) ∼13,000–13,580 yr B.P., 2) ∼10,540–10,830 yr B.P., and 3) ∼8370–8700 yr B.P. • The ages of Wanrendong rock paintings indicate that these paintings were created by Paleolithic hunter-gatherers. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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18. Single ferromagnetic domain observed in single core-shell GaN/GaN:Mn micro-wire grown by metalorganic chemical vapor deposition.
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Jiang, Shengxiang, Zong, Hua, Ji, Cheng, Zhang, Yan, Yang, Zhijian, Wang, Cunda, Chen, Zhizhong, Hu, Xiaodong, and Zhang, Guoyi
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CHEMICAL vapor deposition , *MAGNETIC structure , *MAGNETIC hysteresis , *MAGNETISM , *MAGNETIC properties - Abstract
Spontaneously self-organized growth of core-shell GaN/GaN:Mn micro-wires were obtained by metalorganic chemical vapor deposition (MOCVD) without catalyst. The structure and magnetic properties of single core-shell GaN/GaN:Mn micro-wire were investigated. Mn atoms substituted for the Ga atoms without microprecipitates or clusters in the GaN:Mn shell layer. The magnetic hysteresis curve showed that the core-shell GaN/GaN:Mn micro-wires were ferromagnetic above room temperature. In addition, a single ferromagnetic domain was confirmed by magnetic force microscope (MFM) in the as-grown GaN:Mn shell layer without external magnetic field applied before, excluding secondary phases in GaN:Mn. • Spontaneously self-organized growth of core-shell GaN/GaN:Mn micro-wires were obtained by metalorganic chemical vapor deposition (MOCVD) without catalyst. • Mn atoms substituted for the Ga atoms without microprecipitates or clusters in the GaN:Mn shell layer. • The magnetic hysteresis curve showed that the core-shell GaN/GaN:Mn micro-wires were ferromagnetic above room temperature. • A single ferromagnetic domain was confirmed by magnetic force microscope (MFM) in the as-grown GaN:Mn shell layer without external magnetic field applied before, excluding secondary phases in GaN:Mn. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
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