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Periodicity and attractivity for a rational recursive sequence
Lijie Zhang,Guang Zhang,Hui Liu 한국전산응용수학회 2005 Journal of applied mathematics & informatics Vol.19 No.1-2
In this paper, the existence of periodic positive solution and the attractivity are investigated for the rational recursive sequence xn+1 =(A + axn−k)/(b + xn−l), where A, a and b are real numbers, k and l are nonnegative integer numbers.
PERIODICITY AND ATTRACTIVITY FOR A RATIONAL RECURSIVE SEQUENCE
ZHANG, LIJIE,ZHANG, GUANG,LIU, HUI 한국전산응용수학회 2005 Journal of applied mathematics & informatics Vol.19 No.1
In this paper, the existence of periodic positive solution and the attractivity are investigated for the rational recursive sequence $x_{n+1} = (A + ax_{n_k})/(b + x{n-l})$, where A, a and b are real numbers, k and l are nonnegative integer numbers.
Lijie Tang,Yan Ma,Caixia Yang,Enxiang Liang,Hong Yin,Qiong Wan,Jiance Zhang,Wei Wang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-
Flexible energy storage devices are susceptible to damage, which might result in safety issues. In thispaper, a self-healing flexible P(AAPBA-co-P4-AC) gel electrolyte based on dynamic borate bond crosslinkingstrategy is reported. On the one hand, it is simple to process into complicated shapes or patterns,and on the other hand, it could rapidly return to its original state after stress damage. Even after ten timesself-healing, the gel has the same mechanical properties as the non-damaged gel. Furthermore, this gelcan also be applied in all-solid-state supercapacitors without the need of extra electrolytes. Becausethe gel has a large number of hydroxyl groups, it has a high affinity for the activated carbon electrode,and the supercapacitors can maintain 100% initial performance under various angles or strains. Afterten thousand times cycles charge–discharge, the supercapacitors using the gel after twenty times selfhealingprocess can retain 90% of its initial capacity, which is only 4% lower than the non-damagingsupercapacitors, demonstrating high self-healing ability.
Influence of Porosity on Mechanical Behavior of Porous Cu Fabricated via De‑Alloying of Cu–Fe Alloy
Lijie Zou,Fei Chen,Hao Wang,Qiang Shen,Enrique J. Lavernia,Lianmeng Zhang 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.1
We report on a study of the mechanical behavior of porous Cu containing micron-sized pores and fabricated by de-alloyingof a Cu–Fe precursor alloy. Our results show that the minimum volume fraction of pores that can be obtained by using anapproach that involves de-alloying of a Cu–Fe precursor alloy is approximately 40 vol%. Moreover, the average pore sizeformed by de-alloying Cu–Fe of varying compositions is in the range of 1.5–4.0 μm. Our mechanical behavior results revealthat the yield stress increases from 3.9 to 58.6 MPa as the volume fraction of porosity decreases from 78.9% to 39.3%. Moreover, our data shows that the influence of porosity on the relative yield stress and relative Young’s modulus conformsto the scaling equations of Gibson and Ashby as formulated for open-cell porous metals. The pore cell characteristics anddeformation modes of porous Cu produced by de-alloying Cu–Fe alloys were discussed in the context of the observed fluctuationsin the value of the constants C and n in the Gibson-Ashby scaling equation. The evolution of microstructure duringcompressive deformation of porous Cu was studied and the results reveal an increase in the fraction of low-angle grainboundaries, an increase in the number of twins and a decrease in the average grain size with increasing strain from 0% to 70%.
Lijie Zhao,Rong Geng,Yi Huang,Jiping Zhang,Haiying Cheng,Cankun Zhou,Yifeng Wang 대한부인종양학회 2023 Journal of Gynecologic Oncology Vol.34 No.5
Objective: As a gate-keeper enzyme link, pyruvate dehydrogenase E1 subunit alpha (PDHA1) functions as a key regulator during glycolysis and the mitochondrial citric acid cycle, which has been reported in several tumors. Nevertheless, the effects of PDHA1 on biological behaviors and metabolism remain unclear in cervical cancer (CC) cells. The study aims to explore the PDHA1 effects on glucose metabolism in CC cells and its possible mechanism. Methods: We first determined the expression levels of PDHA1 and activating protein 2 alpha (AP2α) as a PDHA1 potential transcription factor. The effects of PDHA1 in vivo were evaluated through a subcutaneous xenograft mouse model. Cell Counting Kit-8 assay, 5-ethynyl-2′-deoxyuridine (EdU) labeling assay, Transwell invasion assay, wound healing assay, Terminal deoxynucleotidyl transferase dUTP nick end labeling assay and flow cytometry were performed in CC cells. Oxygen consumption rate (OCR) levels were determined to reflect aerobic glycolysis level in gastric cancer cells. Reactive oxygen species (ROS) level was measured with 2′, 7′-dichlorofluorescein diacetate kit. The relationship between PDHA1 and AP2α was examined by conducting chromatin immunoprecipitation assay and electrophoretic mobility shift assay. Results: In CC tissues and cell lines, PDHA1 was downregulated, while AP2α was upregulated. Overexpression of PDHA1 remarkedly inhibited the proliferation, invasion and migration of CC cells, and tumor growth in vivo, as well as promoted OCR, apoptosis and ROS production. Moreover, AP2α directly bound to PDHA1 within suppressor of cytokine signaling 3 promoter region to negatively regulate PDHA1 expression level. What is more, PDHA1 knockdown could effectively reversed the AP2α silencing-mediated suppressive effects on cell proliferation, invasion, migration, and the promotive effects of AP2α knockdown on OCR, apoptosis and ROS production. Conclusions: Our findings demonstrate that AP2α negatively regulated PDHA1 via binding to PDHA1 gene promoter to promote malignant CC cell behaviors, which may provide a potential approach for CC therapeutics.
Minxiu Zhang,Xianwen Deng,Zhixun Xie,Yanfang Zhang,Zhiqin Xie,Liji Xie,Sisi Luo,Qing Fan,Tingting Zeng,Jiaoling Huang,Sheng Wang 대한수의학회 2022 Journal of Veterinary Science Vol.23 No.5
Background: Chicken anemia virus (CAV) causes chicken infectious anemia, which results in immunosuppression; the virus has spread widely in chicken flocks in China. Objectives: The aim of this study was to understand recent CAV genetic evolution in chicken flocks in Guangxi Province, southern China. Methods: In total, 350 liver samples were collected from eight commercial broiler chicken farms in Guangxi Province in southern China from 2018 to 2020. CAV was detected by conventional PCR, and twenty CAV complete genomes were amplified and used for the phylogenetic analysis and recombination analysis. Results: The overall CAV-positive rate was 17.1%. The genetic analysis revealed that 84 CAVs were distributed in groups A, B, C (subgroups C1-C3) and D. In total, 30 of 47 Chinese CAV sequences from 2005-2020 belong to subgroup C3, including 15 CAVs from this study. There were some specific mutation sites among the intergenotypes in the VP1 protein. The amino acids at position 394Q in the VP1 protein of 20 CAV strains were consistent with the characteristics of a highly pathogenic strain. GX1904B was a putative recombinant. Conclusions: Subgroup C3 was the dominant genotype in Guangxi Province from 2018–2020. The 20 CAV strains in this study might be virulent according to the amino acid residue analysis. These data help improve our understanding of the epidemiological trends of CAV in southern China.
SIMULATION STUDY ON VEHICLE RIDE COMFORT BASED ON FINITE ELEMENT MODEL AND PSEUDO-EXCITATION METHOD
Wang Wenzhu,Lijie Dong,Liu Gang,Wei Jun,Zhang Zhenwei 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.4
This research aims to develop a new vehicle ride comfort simulation technology. The basic principle of pseudo-excitation method (PEM) is summarized, and the specific method of PEM is proposed to solve the finite element model (FEM) of vehicle. Taking a simple 7-degree-of-freedom (DOF) car spatial model as an example, the traditional and new methods are compared. Simulation results show that they are completely consistent, thereby verifying the effectiveness of the new method. At the same time, through the simulation process, the new method is simpler and more efficient without deducing complex mathematical formulas and software programming. Finally, the ride comfort simulation of a car’s complex FEM is performed. FEM can consider the parts of the vehicle as elastic bodies and closer to the real vehicle. The PEM transforms random vibration analysis into simple harmonic vibration analysis, which improves the efficiency of the solution greatly. Therefore, the combination of the FEM and the PEM cannot only solve the problem of model accuracy but also the problem of solving efficiency, which has strong practical engineering application value.
Measurement of Spindle Tilt Error based on Interference Fringe
Pengqiang Fu,Yinhong Jiang,Lijie Zhou,Yiwen Wang,Qinghui Cao,Qiang Zhang,Feihu Zhang 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.5
The spindle rotation error is one of the important factors that affect the precision of the machined parts. The study of spindle rotation error is of great significance for finding the source of error, predicting the surface shape error of machining parts and improving the machining accuracy of ultra-precision machine tools. The structural of the aerostatic spindle this article focuses on is motorized spindle and the spindle tilt error has the maximum effect on the machining precision. A new method for measuring the rotation error of ultra-precision aerostatic spindle based on interference fringes is proposed in this paper. By using the principle of phase shifting interferometry, the mathematical model between the shape of interference fringes and the motion law of the spindle rotor is established by theoretical modeling. The interference fringes are processed with gray, smooth filtering, expansion corrosion, and edge detection and so on. The distance and direction of the interference fringes are calculated in the coordinate system, so as to get the spindle tilt error. Finally, the measurement system for the spindle rotation error of the aerostatic spindle is developed. The accuracy and effectiveness of this method are shown based on the experimental results.