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Search Results: 1 - 10 of 120159 matches for " WANG Xiulian "
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Mean Convergence Rate of Derivatives by Lagrange Interpolation on Chebyshev Grids
Wang Xiulian,Ning Jingrui
Discrete Dynamics in Nature and Society , 2011, DOI: 10.1155/2011/503561
Abstract: We consider the rate of mean convergence of derivatives by Lagrange interpolation operators based on the Chebyshev nodes. Some estimates of error of the derivatives approximation in terms of the error of best approximation by polynomials are derived. Our results are sharp. 1. Introduction and Main Results Mean convergence of Lagrange interpolation based on the zeros of orthogonal polynomials (and possibly some additional points) has been studied for at least 70 years. There is a vast literature on this topic. The authors of [1–3] considered the simultaneous approximation by the Hermite interpolation operators, and we will consider the simultaneous approximation by Lagrange interpolation operators based on the zeros of Chebyshev polynomials. The relevant results can be found in [4–6]. We introduce these results below. Let be a so-called generalized Jacobi weight ( ), and let be the zeros of the th orthogonal polynomial associated with the weight-function . Let denote the Lagrange interpolating polynomial which interpolates at the zeros of . By using Markov-Bernstein type inequalities in metric, J. Szabados and A. K. Varma [5] reduced the weighted mean convergence of derivatives to the weighted mean convergence of and obtained the following. If means functional space equipped with norm and then, for , we have Here and in the following, the constant (may be different in the same expression) is independent of and but depends on , and denotes the error of the best polynomial approximation of degree of the corresponding function in the metric. Mastroianni and Nevai [4] get sharper estimates in terms of modulus of continuity instead of the best approximation. It improves some old results. But its proof also needs weighted Markov-Bernstein type inequality in metric and the idea of additional points. For the weight functions not satisfying (*), it is not possible to discuss by their method. To deal with these case, Du and Xu [7] consider the most important special case . Let be the zeros of , the th degree Chebyshev polynomial of the first kind. If , then the well-known Lagrange interpolation polynomial of based on is given by (see [8]) where Du and Xu [7] obtained the following. Theorem A. Let be as defined as above. Then, for , we have and the estimation for is sharp. We notice that although the sharp estimate is obtained, the upper bound is not for . Now we will give a Lagrange interpolation to improve their results. Let be the zeros of , the th degree Chebyshev polynomial of the second kind. If , then the well-known Lagrange interpolation polynomial of based
Spacetime variation of $α$ and the CMB power spectra after the recombination
Xiulian Wang,Mingzhe Li
Physics , 2009, DOI: 10.1142/S0217732311034360
Abstract: The possible variation of the fine structure constant may be due to the non-minimal coupling of the electromagnetic field to a light scalar field which can be the candidate of dark energy. Its dynamical nature renders the fine structure constant varies with time as well as space. In this paper we point out the spatial fluctuation of the fine structure will modify the power spectra of the temperature and the polarization of the cosmic microwave background. We show explicitly that the fluctuations of the coupled scalar field generate new temperature anisotropies at the linear order and induce a $B$ mode to the polarization at higher order in general.
Metric-Affine Formalism of Higher Derivative Scalar Fields in Cosmology
Mingzhe Li,Xiulian Wang
Physics , 2012, DOI: 10.1088/1475-7516/2012/07/010
Abstract: Higher derivative scalar field theories have received considerable attention for the potentially explanations of the initial state of the universe or the current cosmic acceleration which they might offer. They have also attracted many interests in the phenomenological studies of infrared modifications of gravity. These theories are mostly studied by the metric variational approach in which only the metric is the fundamental field to account for the gravitation. In this paper we study the higher derivative scalar fields with the metric-affine formalism where the connections are treated arbitrarily at the beginning. Because the higher derivative scalar fields couple to the connections directly in a covariant theory these two formalisms will lead to different results. These differences are suppressed by the powers of the Planck mass and are usually expected to have small effects. But in some cases they may cause non-negligible deviations. We show by a higher derivative dark energy model that the two formalisms lead to significantly different pictures of the future universe.
Study on the Relationship between Expression of LGR5 and Clinicopathological Characteristics in Gastric Cancer Patients  [PDF]
Xiulian Xu, Qijun Lv, Ping Xie, Shoujiang Wei, Chongshu Wang
Health (Health) , 2018, DOI: 10.4236/health.2018.101013
Abstract: The aim of the study was to clarify the role of LGR5 in the process of formation and development of gastric cancer. The expression of LGR5 in gastric cancer and corresponding non-cancerous gastric tissues of 52 gastric cancer patients was assessed with the real-time fluorescence quantitative polymerase chain reaction (RT-PCR) and immunohistochemistry. We also analyzed the relationship between the expression level and clinicopathological characteristics. LGR5 gene and protein expression in gastric cancer tissues was in both cases significantly higher than in corresponding non-cancerous gastric tissues (both P < 0.05), but no significant relationship was found with clinicopathological parameters including tumor location, depth of invasion, differentiation, lymph node metastasis, stage, gender, age and carcinoembryonic antigen (CEA), and carbohydrate antigen 19-9 (CA19-9) level in peripheral blood pre-operation of patients (P > 0.05, respectively). Furthermore, LGR5 gene expression was markedly higher in gastric cancer tissues of Helicobacter pylori (HP)-positive patients than negative ones (P < 0.05). The result of the study showed that LGR5 might play a significant role in the process of formation and development of gastric cancer as an oncogene. Its effect might be strengthened by HP infection.
Study on the Relationship between Stromal Cell-Derived Factor-1 (SDF-1) and Gastric Cancer  [PDF]
Xiulian Xu, Yurong Song, Shoujiang Wei, Chongshu Wang
Health (Health) , 2019, DOI: 10.4236/health.2019.113029
Abstract: Whether SDF-1 is related to the occurrence and development of gastric cancer, we collected gastric cancer tissues and corresponding non-cancerous gastric tissues from 52 patients with gastric cancer, and detected the expression of SDF-1 by real-time fluorescence quantitative polymerase chain reaction (RT-PCR) and immunohistochemistry. We also analyzed the relationship between the expression level and clinicopathological characteristics. In both cases SDF-1 gene and protein expression in gastric cancer tissues were significantly higher than in corresponding non-cancerous gastric tissues (both P < 0.01), but no significant relationship was found with clinicopathological parameters including tumor location, depth of invasion, differentiation, lymphnode metastasis, stage, gender, age and carcinoembryonic antigen (CEA), and carbohydrate antigen 19-9 (CA19-9) level in peripheral blood preoperation of patients (P > 0.05, respectively). Also, there were no significant relations hip in gastric cancer tissues of Helicobacter pylori (HP)-positive patients and negative ones (P > 0.05). The result of the study showed that SDF-1 might play a significant role in the process of formation and development of gastric cancer as an oncogene, but could not be used as an index to judge prognosis and predict recurrence.
Direct production of light olefins from syngas over a carbon nanotube confined iron catalyst
ChuanFu Wang,XiuLian Pan,XinHe Bao
Chinese Science Bulletin , 2010, DOI: 10.1007/s11434-010-0076-8
Abstract: Iron particles confined in carbon nanotube (CNT) channels have been used as a catalyst for the direct conversion of syngas to light olefins. Compared with iron catalysts supported on other materials such as Silica-1, SBA-15 and carbon black, the CNT-confined catalyst exhibits a higher CO conversion and selectivity to the light olefins. This can be attributed to the CNT channels, which provide a unique confinement environment for iron particles.
Direct production of light olefins from syngas over a carbon nanotube confined iron catalyst

ChuanFu Wang,XiuLian Pan,XinHe Bao,

科学通报(英文版) , 2010,
Abstract: Iron particles confined in carbon nanotube (CNT) channels have been used as a catalyst for the direct conversion of syngas to light olefins.Compared with iron catalysts supported on other materials such as Silica-1,SBA-15 and carbon black,the CNT-confined catalyst exhibits a higher CO conversion and selectivity to the light olefins.This can be attributed to the CNT channels,which provide a unique confinement environment for iron particles.
Assessing the Effects of the Uncertainty in Reheating Energy Scale on Primordial Spectrum and CMB
Bo Feng,Xiaobo Gong,Xiulian Wang
Physics , 2003, DOI: 10.1142/S0217732304014896
Abstract: The details of reheating energy scale $\rho_{reh}$ is largely uncertain today, independent of inflation models. This would induce uncertainty in predicting primordial spectrum. Such uncertainty could be very large, especially for spectra with large running $n_S$. We find that for some inflation models with a large $d\ln n_S(k)/d\ln k$, $\rho_{reh}$ could be highly restricted by current CMB observations.
Dark Energy and Neutrino Mass Limits from Baryogenesis
Peihong Gu,Xiulian Wang,Xinmin Zhang
Physics , 2003, DOI: 10.1103/PhysRevD.68.087301
Abstract: In this brief report we consider couplings of the dark energy scalar, such as Quintessence to the neutrinos and discuss its implications in studies on the neutrino mass limits from Baryogenesis. During the evolution of the dark energy scalar, the neutrino masses vary, consequently the bounds on the neutrino masses we have here differ from those obtained before.
Relationship between expression of Aurka and clinicopathological characteristics in gastric cancer patients  [PDF]
Xiulian Xu, Jiangwei Xiao, Shoujiang Wei, Xianyong Xie, Yifan Huang, Xiaobing Tian, Chongshu Wang
Health (Health) , 2014, DOI: 10.4236/health.2014.64036
Abstract: The aim of the study was to clarify the role of Aurka in the process of formation and development of gastric cancer. The expression of Aurka in gastric cancer and corresponding non-cancerous gastric tissues of 52 gastric cancer patients was assessed with the real-time fluorescence quantitative polymerase chain reaction (RT-PCR) and immunohistochemistry. We also analyzed the relationship between the expression level and clinicopathological characteristics. Aurka gene and protein expression in gastric cancer tissues in both cases were significantly higher than in corresponding non-cancerous gastric tissues (both P < 0.01), but no significant relationship was found with clinicopathological parameters including tumor location, depth of invasion, differentiation, lymph node metastasis, stage, gender, age and carcinoembryonic antigen (CEA), and carbohydrate antigen 19-9 (CA19-9) level in peripheral blood preoperation of patients (P > 0.05, respectively). Furthermore, Aurka gene expression was markedly higher in gastric cancer tissues of Helicobacter pylori (HP)-positive patients than negative ones (P < 0.05). The result of the study showed that Aurka might play a significant role in the process of formation and development of gastric cancer as an oncogene. Its effect might be strengthened by HP infection.
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