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  • Zhao, Jingmin  (3)
  • Unknown  (3)
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  • Unknown  (3)
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  • 1
    Online Resource
    Online Resource
    American Astronomical Society ; 2021
    In:  The Astrophysical Journal Supplement Series Vol. 257, No. 2 ( 2021-12-01), p. 34-
    In: The Astrophysical Journal Supplement Series, American Astronomical Society, Vol. 257, No. 2 ( 2021-12-01), p. 34-
    Abstract: In this paper, we design an effective and robust model to solve the 3D single-fluid solar wind plasma magnetohydrodynamics (MHD) problem of low plasma β . This MHD model is formulated on a six-component composite grid system free of polar singularities. The computational domain ranges from the solar surface to the super-Alfvénic region. As common to all MHD codes, this code must handle the physical positivity-preserving property, time-step enlargement, and magnetic field divergence-free maintenance. To maintain physical positivity, we employ a positivity-preserving Harten–Lax–van Leer Riemann solver and take a self-adjusting and positivity-preserving method for variable reconstruction. To loosen the time-step limitation, we resort to the implicit lower–upper symmetric Gauss–Seidel method and keep the sparse Jacobian matrix diagonally dominant to improve the convergence rate. To deal with the constant theme of a magnetic field that is divergence-free, we adopt a globally solenoidality-preserving approach. After establishing the solar wind model, we use its explicit and implicit versions to numerically investigate the steady-state solar wind in Carrington rotations (CRs) 2172 and 2210. Both simulations achieve almost the same results for the two CRs and are basically consistent with solar coronal observations and mapped in situ interplanetary measurements. Furthermore, we use the implicit method to conduct an ad hoc simulation by multiplying the initial magnetic field of CR 2172 with a factor of 6. The simulation shows that the model can robustly and efficiently deal with the problem of a plasma β as low as about 5 × 10 −7 . Therefore, the established implicit solar wind MHD model is very promising for simulating complex and strong magnetic environments.
    Type of Medium: Online Resource
    ISSN: 0067-0049 , 1538-4365
    RVK:
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2021
    detail.hit.zdb_id: 2006860-8
    detail.hit.zdb_id: 2207650-5
    SSG: 16,12
    Location Call Number Limitation Availability
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  • 2
    Online Resource
    Online Resource
    American Astronomical Society ; 2023
    In:  The Astrophysical Journal Supplement Series Vol. 265, No. 1 ( 2023-03-01), p. 19-
    In: The Astrophysical Journal Supplement Series, American Astronomical Society, Vol. 265, No. 1 ( 2023-03-01), p. 19-
    Abstract: The present study aims to apply an implicit high-order reconstructed discontinuous Galerkin (DG) scheme (rDG( P 1 P 2 )) to simulate the steady-state solar corona. In this scheme, a piecewise quadratic polynomial solution, P 2 , is obtained from the underlying piecewise linear DG solution, P 1 , by least-squares reconstruction with a weighted essentially nonoscillatory limiter. The reconstructed quadratic polynomial solution is then used for the computation of the fluxes and source terms. In addition, an implicit time integration method with large time steps is considered in this work. The resulting large linear algebraic system of equations from the implicit discretization is solved by the cellwise relaxation implicit scheme which can make full use of the compactness of the DG scheme. The code of the implicit high-order rDG scheme is developed in Fortran language with message passing interface parallelization in Cartesian coordinates. To validate this code, we first test a problem with an exact solution, which confirms the expected third-order accuracy. Then we simulate the solar corona for Carrington rotations 2167, 2183, and 2210, and compare the modeled results with observations. We find that the numerical results basically reproduce the large-scale observed structures of the solar corona, such as coronal holes, helmet streamers, pseudostreamers, and high- and low-speed streams, which demonstrates the capability of the developed scheme.
    Type of Medium: Online Resource
    ISSN: 0067-0049 , 1538-4365
    RVK:
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2023
    detail.hit.zdb_id: 2006860-8
    detail.hit.zdb_id: 2207650-5
    SSG: 16,12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    In: Global Translational Medicine, AccScience Publishing, Vol. 1, No. 2 ( 2022-08-12), p. 94-
    Abstract: Liver cirrhosis has been a well-known risk factor for the development of hepatocellular carcinoma (HCC). However, this view has recently been challenged. This study aimed to investigate the potential association of cirrhosis with hepatitis B virus (HBV)-related HCC. In this study, two independent multicenter clinical cohorts that included 1,431 HCC patients with chronic HBV infection were retrospectively studied. The first cohort consisted of 334 HCC patients undergoing curative resection and cirrhosis, who have been pathologically diagnosed. The second cohort consisted of 1,087 HCC patients, who have been diagnosed for the presence of cirrhosis based on clinical evidence. Patients of each cohort were further divided into different subgroups according to the presence of cirrhosis and the severity of the cirrhosis. In both cohorts, patients with cirrhosis had smaller tumor size compared to those without cirrhosis (P 〈 0.05) and a relatively lower proportion of large tumor, defined as tumor size 〉 5 cm in diameter (P 〈 0.05). Patients with decompensated cirrhosis had the highest rate of vascular invasion and/or extrahepatic metastases compared with compensated cirrhosis and non-cirrhosis (53.0% vs. 24.8% vs. 26.9%, P 〈 0.001). In the first cohort, globulin (odds ratio [OR] = 1.096, P = 0.001) and vascular invasion (OR = 4.013, P = 0.013) were independent risk predictors of HCC tumor size 〉 5 cm, while cirrhosis stage Laennec 4B/C was a protective factor (OR = 0.372, P = 0.002). Similar results were observed in the second cohort. In conclusion, this study implied that HCC patients with compensated cirrhosis tend to harbor smaller tumor, but severe cirrhosis favors tumor vascular invasion and metastasis.
    Type of Medium: Online Resource
    ISSN: 2811-0021
    URL: Issue
    Language: Unknown
    Publisher: AccScience Publishing
    Publication Date: 2022
    Location Call Number Limitation Availability
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