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133 results on '"Huang, Yanhe"'

7. Nontrivial linear projections of the Grassmannian Gr_3(C^6)

Author

Huang, Yanhe, Petroulakis, George, Sottile, Frank, and Zelenko, Igor

Subjects
Mathematics - Algebraic Geometry, Mathematics - Optimization and Control, 14M15, 34A30, 93B55
Abstract

A typical linear projection of the Grassmannian in its Plucker embedding is injective, unless its image is a projective space. A notable exception are self-adjoint linear projections, which have even degree. We consider linear projections of Gr_3(C^6) with low-dimensional centers of projection. When the center has dimension less than five, we show that the projection has degree 1. When the center has dimension five and the projection has degree greater than 1, we show that it is self-adjoint., Comment: 14 pages

Published
2020

14. Injectivity of generalized Wronski maps

Author

Huang, Yanhe, Sottile, Frank, and Zelenko, Igor

Subjects
Mathematics - Algebraic Geometry
Abstract

We study linear projections on Pluecker space whose restriction to the Grassmannian is a non-trivial branched cover. When an automorphism of the Grassmannian preserves the fibers, we show that the Grassmannian is necessarily of m-dimensional linear subspaces in a symplectic vector space of dimension 2m, and the linear map is the Lagrangian involution. The Wronski map for a self-adjoint linear differential operator and pole placement map for symmetric linear systems are natural examples., Comment: 14 pages

Published
2016
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24. The Distribution Characteristics and Potential Risk Assessment of Lead in the Soil of Tieguanyin Tea Plantations in Anxi County, China.

Author

Zhan, Yuanyuan, Zhu, Qin, Li, Xiaolin, Tao, Changwu, Su, Huogui, Wu, Yuede, Lin, Jinshi, Zhang, Yue, Huang, Yanhe, and Jiang, Fangshi

Subjects
TEA plantations, LEAD in soils, TEA growing, RISK assessment, SOIL quality, PLATEAUS
Abstract

Assessing the distribution and risks associated with the soil lead content in the Tieguanyin tea plantations of Anxi County is critical, given the county's significance as the primary Tieguanyin tea production area in Fujian Province. This study examined the distribution characteristics of soil lead in Anxi County's tea plantations according to the Kriging spatial interpolation of the parameters of the semivariance function of the exponential model. Moreover, the sources of lead content were analyzed, considering geological backgrounds and anthropogenic influences. Ecological risks and the issuance of early warnings were also assessed. The soil lead content in the rocks of the Tieguanyin tea plantations in Anxi County followed the order: andesite > dacite > rhyolite > granite. The soil lead content gradually decreased from the center toward the east and west, forming four distinct north–south parallel zones. High-lead-content areas were identified at the border of Jiandou, Bailai, and Hushang; in the central part of Lutian; and in the southern part of Huqiu. The high levels of soil lead in the tea plantations possibly originated from industrial and mining activities, automobile exhaust, and agricultural activities. The distribution of single-factor pollution indices and potential risk evaluation based on the Soil Environmental Quality Standard, Environmental Technical Conditions for Tea Production Area, and Environmental Technical Conditions for Organic Tea Production Area indicated that the soil in Tieguanyin tea plantations in Anxi County was clean and safe for tea cultivation. [ABSTRACT FROM AUTHOR]

Published
2024
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26. A Boundary Integral Method for Modeling Axisymmetric Flow Around a Rising Bubble in a Vertical Tube and Accurate Numerical Evaluation of Orthogonal Polynomials

Author

Huang, Yanhe

Subjects
Mathematics, Applied mathematics
Abstract

Axisymmetric flow around a bubble rising in a 3D fluid has been studied intensively both numerically and experimentally over the years, but in the high Reynolds number regime, no matter for small oblate or elongated bubbles, current mathematical models face problems such as introducing an unnecessary singularity at the stagnation point, missing proper lower boundary conditions, and solving with low order finite difference methods, which leads to large numerical errors. Modeling the problem by both potential flow and viscous potential flow, we can represent the velocity potential using layer potentials and compute the bubble shape with spectral accuracy, with average numerical errors around $10^{-9}$. A dimensionless inviscid model is first built to study steady flow around a bubble in an infinitely long tube in the case of zero gravity. With a comprehensive discussion on parametrization, singular integrals, and numerical quadrature, we solve both oblate and elongated bubble shapes accurately and find different solution branches of bubble shapes characterized by the number of humps. These solution branches relating the Weber number and cross-section arc-length suggest that for any nonzero surface tension, there exists a countably infinite number of solutions. When there is gravity, kinematic viscosity is introduced to balance out the normal stress on the bubble surface. Different shapes of steadily rising bubbles under different Froude numbers are presented. We also study the corresponding time-dependent problem to illustrate the dynamics of unsteady bubbles, both small and elongated, and to confirm the non-existence of steadily rising bubbles in the inviscid model with nonzero gravity. The approximation of dipole density by spherical harmonics is computed to remove the hyper-singularity in the normal derivatives of the double layer potential on the bubble surface. Due to the importance of accurate evaluation of orthogonal polynomials in the boundary integral method, we introduce a new way to evaluate orthogonal polynomials more accurately near the endpoints of the integration interval by evaluating a newly created set of associated orthogonal polynomials at corresponding points. Various ways to evaluate the associated orthogonal polynomials are discussed and implemented. Among them, the best method can achieve round-off error accuracy even for end-point evaluation of generic high-degree Jacobi polynomials and generalized Laguerre polynomials, which is 3 digits more accurate than the classic recurrence method in double precision when the degree is around 400. Based on the accurate evaluation, we perform one iteration of Newton's method to achieve more accurate quadrature abscissas near endpoints. We also calculate quadrature weights using the Christoffel formula based on our accurate evaluation. The resulting errors in abscissas and weights are compared to those of the Golub-Welsch algorithm, with our method being more accurate. Strategies on generic weight functions are given and tested on Maxwell polynomials of current interest in plasma physics.

Published
2020

39. Mutagenesis by acrolein-derived propanodeoxyguanosine adducts in human cells

Author

Yang, In-Young, Chan, Grace, Miller, Holly, Huang, Yanhe, Torres, Maria Cecilia, Johnson, Francis, and Moriya, Masaaki

Subjects
Cells -- Physiological aspects, Aldehydes, Guanosine, Genetic toxicology -- Research, Biological sciences, Chemistry
Abstract

Research has been conducted on acrolien, a member of the alpha, beta-unsaturated aldehyde family. The role of alpha-OH-1,N (super)2 ?propanodeoxyguanosine adduct in the genotoxicity of this acrolein has been investigated via comparison of alpha-OH-1,N (super)2 ?propanodeoxyguanosine, gamma-OH-1,N (super)2 ?propanodeoxyguanosine and propanodeoxyguanosine by in vitro primer extension studies and in human cells and the details are reported.

Published
2002

47. A comparison of the effectiveness of the roots of two grass species in reducing soil erosion on alluvial fans in south‐east China.

Author

Jiang, Fangshi, He, Kaiwen, Lin, Jiahui, Li, Hui, Zhan, Zhenzhi, Lin, Jinshi, Ge, Hongli, Wang, Ming Kuang, and Huang, Yanhe

Subjects
ALLUVIAL fans, FLUVISOLS, GRASSLANDS, SOIL cohesion, SHEAR flow, SOIL erosion, SOIL density
Abstract

The effects of root systems on soil detachment by overland flow are closely related to vegetation types. The objective of this study was to quantify the effects of two gramineous roots (Paspalum mandiocanum with shallow roots and Pennisetum giganteum with deep roots) on soil detachment capacity, rill erodibility, and critical shear stress on alluvial fans of benggang in south‐east China. A 4‐m‐long and 0.12‐m‐wide flume was used. Slope steepness ranged from 9% to 27%, and unit flow discharge ranged from 1.39 × 10−3 to 4.19 × 10−3 m2 s−1. The mean detachment capacities of P. mandiocanum and P. giganteum lands were 18% and 38% lower than that of bare land, respectively, and the effects of root on reducing soil detachment were mainly reflected in the 0‐ to 5‐cm soil layer. The most important factors in characterizing soil detachment capacity were root length density and soil cohesion, and soil detachment capacity of the two grass lands could be estimated using flow shear stress, soil cohesion, and root length density (NSE = 0.90). With the increase in soil depth, rill erodibility increased, whereas shear stress decreased. The mean rill erodibilities of P. mandiocanum and P. giganteum lands were 81% and 61% as much as that of bare land, respectively. Additionally, rill erodibilities of the two grass lands could be estimated as an exponential function by root length density and soil cohesion (NSE = 0.88). The mean critical shear stress of P. mandiocanum and P. giganteum lands was 1.29 and 1.39 times that of bare land, respectively, and it could be estimated with a linear function by root length density (NSE = 0.76). This study demonstrated that planting of the two grasses P. mandiocanum and P. giganteum could effectively reduce soil detachment and enhance soil resistance to erosion on alluvial fans, with the deep roots of P. giganteum being more effective than the shallow roots of P. mandiocanum. The results are helpful for understanding the influencing mechanism of root systems on soil detachment process. [ABSTRACT FROM AUTHOR]

Published
2020
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