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Which weighted shifts are flat ?
Hailong Shen,Chunji Li 한국전산응용수학회 2020 Journal of applied mathematics & informatics Vol.38 No.5
The flatness property of a unilateral weighted shifts is important to study the gaps between subnormality and hyponormality. In this paper, we first summerize the results on the flatness for some special kinds of a weighted shifts. And then, we consider the flatness property for a local-cubically hyponormal weighted shifts, which was introduced in [2]. Let alpha :sqrt{frac{2}{3}}, sqrt{frac{2}{3}}, { sqrt{frac{n+1}{n+2}}} _{n=2}^{infty } and let W_{alpha} be the associated weighted shift. We prove that W_{alpha} is a local-cubically hyponormal weighted shift W_{alpha} of order theta =frac{pi }{4} by numerical calculation.
PRECONDITIONED GAUSS-SEIDEL ITERATIVE METHOD FOR Z-MATRICES LINEAR SYSTEMS
Shen, Hailong,Shao, Xinhui,Huang, Zhenxing,Li, Chunji Korean Mathematical Society 2011 대한수학회보 Vol.48 No.2
For Ax = b, it has recently been reported that the convergence of the preconditioned Gauss-Seidel iterative method which uses a matrix of the type P = I + S (${\alpha}$) to perform certain elementary row operations on is faster than the basic Gauss-Seidel method. In this paper, we discuss the adaptive Gauss-Seidel iterative method which uses P = I + S (${\alpha}$) + $\bar{K}({\beta})$ as a preconditioner. We present some comparison theorems, which show the rate of convergence of the new method is faster than the basic method and the method in [7] theoretically. Numerical examples show the effectiveness of our algorithm.
Preconditioned Gauss-Seidel iterative method for Z-matrices linear systems
Hailong Shen,Xinhui Shao,Zhenxing Huang,Chunji Li 대한수학회 2011 대한수학회보 Vol.48 No.2
For Ax=b, it has recently been reported that the convergence of the preconditioned Gauss-Seidel iterative method which uses a matrix of the type P=I+S(α) to perform certain elementary row operations on is faster than the basic Gauss-Seidel method. In this paper, we discuss the adaptive Gauss-Seidel iterative method which uses P=I+S(α) +[기호](β) as a preconditioner. We present some comparison theorems, which show the rate of convergence of the new method is faster than the basic method and the method in [7] theoretically. Numerical examples show the effectiveness of our algorithm.
Current progress on gold recovery from refractory ore and waste electrical and electronic equipment
Ji Xuran,Shen Zhijie,Xu Wenping,Yao Shimiao,Zhang Hairong,Xiong Lian,Li Hailong,Guo Haijun,Chen Xuefang,Chen Xinde 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.9
The physical and chemical properties of gold promote its application, such as in the high-tech, electronic products, and aerospace industries. The easily leachable ore is gradually depleted. Thus, it becomes necessary to extract gold from other resources such as refractory ore and electrical and electronic equipment. The normal method of leaching for gold is cyanide leaching, but it is very dangerous for both environment and operator. Non-cyanide leaching methods, including thiourea leaching, halide leaching, and sulfate leaching have been developed to substitute cyanide leaching. A variety of methods to enrich gold from leaching solutions are described in this paper, including solvent extraction, electrowinning, activated carbon adsorption, and ion exchange resins. Among those methods, ion exchange resins can adsorb gold with high adsorption efficiency and regenerate easily as well. This paper focuses on the research progress of the recovery of gold from non-cyanide leachates by ion exchange resins, summarizes the existing resin types and elution processes, points out the limitations in the application of current ion exchange resins, and discusses possible solutions.
Vitellogenin’s putative role in Tegillarca granosa’s cadmium detoxification
Caifang Chen,Weiliang Shen,Hailong Gu,Linde Wu,Zhihua Lin,Qinggang Xue 한국유전학회 2017 Genes & Genomics Vol.39 No.2
The bloody clam, Tegillarca granosa, is a commercial benthic bivalve, having a strong accumulation ability and torrelence to cadmium. To investigate whether vitellogenin (Vg) is involved in cadmium (Cd) detoxification, the full-length cDNA of T. granosa Vg was cloned, and its expression pattern in response to cadmium exposure was studied compared with the reference metallothionein (MT) gene. The full T. granosa Vg sequence consisted of 8988 bp, including a 6930-bp open reading frame that encoded a 2309 amino acid polypeptide. The deduced Vg protein contained a Vg N-terminal domain, domain of unknown function (DUF1943), SbcC domain, and von Willebrand factor typeD domain (VWD). Multiple metal-binding sites were predicted in the deduced T. granosaVg protein, suggesting its potential in functioning as a metal-binding protein. In addition, Vg expression increased in the T. granosa digestive gland and hemolymph in time-dependent manner after exposure to 1, 3, 6 and 9 lg/L Cd for 28 days.MTexpression was measured in parallel with Vg expression, and the latter was more sensitive to Cd induction than the former. Together, results of the present research suggested that Vg may play an important role in T. granosa metal detoxification.
LDL Coating pVEGF/polyethylenimine Complex Enhances Vascular Endothelial Growth Factor Expression
Jian Li,Guang Yang,Min Feng,Hailong Liang,Jun Zhang,Danhong Huang,Siyun Deng,Yuan Shen 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.6
The major limitations to non-viral gene delivery are relatively low efficiency and cytotoxicity, which need to be addressed in the design of new vectors. In this study,negatively charged low density lipoproteins (LDL) were coated onto positively charged pVEGF/PEI complexes to form pVEGF/PEI/LDL terplexes by a two-step procedure. The biocompatible LDL was introduced to reduce the cytotoxicity of the gene delivery system and increase its affinity to cells. The successful formation of pVEGF/PEI/LDL terplexes was confirmed by their near-neutral and slightly negative surface charges. The pVEGF/PEI/LDL terplexes were well-defined sub-micron spherical particles. On the cell viability assay, both of the PEI/LDL combined vector and pVEGF/PEI/LDL terplexes exhibited much lower cytotoxicity to HeLa cells and HUVE cells than those of PEI and pVEGF/PEI complexes, attributed to the shielding effect of the LDL. pEGFP/PEI/LDL terplexes showed significantly higher transfection efficiency in comparison to pEGFP/PEI complexes in serum-containing medium. pVEGF/PEI/LDL terplexes at their optimal N/P ratio and LDL/PEI weigh ratio induced higher expression levels of VEGF protein in HUVE cells than those of pVEGF/PEI complexes. Therefore, the pVEGF/PEI/LDL terplexes could be used as a promising gene delivery system to enhance VEGF protein expression.