MULTIPLICITY OF POSITIVE SOLUTIONS FOR MULTIPOINT BOUNDARY VALUE PROBLEMS WITH ONE-DIMENSIONAL P-LAPLACIAN

Zhang, Youfeng,Zhang, Zhiyu,Zhang, Fengqin The Korean Society for Computational and Applied M 2009 Journal of applied mathematics & informatics Vol.27 No.5

In this paper, we consider the multipoint boundary value problem for the one-dimensional p-Laplacian $({\phi}_p(u'))'$(t)+q(t)f(t,u(t),u'(t))=0, t $\in$ (0, 1), subject to the boundary conditions: $u(0)=\sum\limits_{i=1}^{n-2}{\alpha}_iu({\xi}_i),\;u(1)=\sum\limits_{i=1}^{n-2}{\beta}_iu({\xi}_i)$ where $\phi_p$(s) = $|s|^{n-2}s$, p > 1, $\xi_i$ $\in$ (0, 1) with 0 < $\xi_1$ < $\xi_2$ < $\cdots$ < $\xi{n-2}$ < 1 and ${\alpha}_i,\beta_i{\in}[0,1)$, 0< $\sum{\array}{{n=2}\\{i=1}}{\alpha}_i,\sum{\array}{{n=2}\\{i=1}}{\beta}_i$<1. Using a fixed point theorem due to Bai and Ge, we study the existence of at least three positive solutions to the above boundary value problem. The important point is that the nonlinear term f explicitly involves a first-order derivative.

Multiplicity of positive solutions for multipoint boundary value problems with one-dimensional p-Laplacian

Youfeng Zhang,Zhiyu Zhang,Fengqin Zhang 한국전산응용수학회 2009 Journal of applied mathematics & informatics Vol.27 No.5

In this paper, we consider themultipoint boundary value prob- lem for the one-dimensional p-Laplacian (∅p(u'))'(t) + q(t)f(t,u(t), u'(t)) = 0, t ∈ (0, 1), subject to the boundary conditions: u(0) =<수식> , u(1) =<수식> where ∅p(s) = |s|n−2s, p > 1, ξi ∈ (0, 1) with 0 < ξ1 < ξ2 < · · · < ξn−2 < 1 and αi, βi ∈ [0, 1), 0 < <수식> ,<수식> βi < 1. Using a fixed point theoremdue to Bai and Ge, we study the existence of at least three positive solutions to the above boundary value problem. The important point is that the nonlinear term f explicitly involves a first-order derivative. In this paper, we consider themultipoint boundary value prob- lem for the one-dimensional p-Laplacian (∅p(u'))'(t) + q(t)f(t,u(t), u'(t)) = 0, t ∈ (0, 1), subject to the boundary conditions: u(0) =<수식> , u(1) =<수식> where ∅p(s) = |s|n−2s, p > 1, ξi ∈ (0, 1) with 0 < ξ1 < ξ2 < · · · < ξn−2 < 1 and αi, βi ∈ [0, 1), 0 < <수식> ,<수식> βi < 1. Using a fixed point theoremdue to Bai and Ge, we study the existence of at least three positive solutions to the above boundary value problem. The important point is that the nonlinear term f explicitly involves a first-order derivative.

Illumination correction via improved grey wolf optimizer for regularized random vector functional link network

Xiaochun Zhang,Zhiyu Zhou 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.3

In a random vector functional link (RVFL) network, shortcomings such as local optimal stagnation and decreased convergence performance cause a reduction in the accuracy of illumination correction by only inputting the weights and biases of hidden neurons. In this study, we proposed an improved regularized random vector functional link (RRVFL) network algorithm with an optimized grey wolf optimizer (GWO). Herein, we first proposed the moth-flame optimization (MFO) algorithm to provide a set of excellent initial populations to improve the convergence rate of GWO. Thereafter, the MFO-GWO algorithm simultaneously optimized the input feature, input weight, hidden node and bias of RRVFL, thereby avoiding local optimal stagnation. Finally, the MFO-GWO-RRVFL algorithm was applied to ameliorate the performance of illumination correction of various test images. The experimental results revealed that the MFO-GWO-RRVFL algorithm was stable, compatible, and exhibited a fast convergence rate.

A new method of synthesis on high-quality AgGaS2 polycrystalline

Jianjun Zhang,Shifu Zhu,Beijun Zhao,Baojun Chen,Zhiyu He 한국물리학회 2010 Current Applied Physics Vol.10 No.2

High-pure, single-phase, free of voids and high mass density AgGaS2 polycrystalline was synthesized by a new method, i.e. two-temperature zone vapor-transporting together with the mechanical and melt temperature oscillation method (TVMMTOM), directly from high-purity (6 N) elements silver, gallium and sulfur with excess sulfur. The mechanism and advantages of the new method for synthesizing high-quality AgGaS2 were discussed. It is found that the polycrystalline material synthesized by the new method is superior to that synthesized by the conventional method, what is more the new method can avoid the explosion of the synthetic quartz ampoule. Adopting the modified Bridgman method an integral and crack-free AgGaS2 single crystal with diameter of 14 mm and length of 63 mm has been obtained. It was found that there was a (1 0 1) cleavage face and the four order X-ray spectrum of the {1 0 1} faces was observed. By the method of DSC analysis the melting and freezing points of the AgGaS2 single crystal were about 995 and 955 ℃. The transmission spectra of the AgGaS2 sample of 10 × 8 ×2㎣ were obtained by means of UV and IR spectrophotometer. The limiting wavelength was 470 nm and the band gap was 2.64 eV. It can be found in the infrared spectrum that the infrared transmission was above 55%from 4000 to 800 cm-1, and the infrared transmittance of the crystal is up to 63% at 10.6 lm, which is higher than that of the crystal grown using polycrystalline materials synthesized by the conventional method. The value of a in 10.6 lm was 0.267 cm-1. Above mentioned results showed that the crystal was of good quality and TVMMTOM is preferable for synthesizing high-quality AgGaS2 polycrystalline materials.

A Fuzzy Evaluation Method of Power Transformer Insulation Health State Based on Multi-weight Fusion

Li Jifang,Zhang Haiyang,Wang Zhiyue,Feng Zhen 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.4

During the evaluation of transformer insulation health state, the weight of each evaluation indicator has a signifi cant infl uence on its evaluation result. To overcome the existing problem of determining the weight of evaluation indicators by a single method, this paper proposes a comprehensive weight fuzzy evaluation method based on multi-weight fusion. Firstly, the proposed method uses principal component analysis (PCA) method to determine the objective weight of each evaluation indicator based on the measured data of the power transformer. Then years of practical experiences from industry experts are introduced to subjectively study the relative importance of the evaluation indicator’s infl uences on the insulation health states and to build the relative importance of judgment matrix of relative relationship. The subjective weight of each indicator is determined by using the analytic hierarchy process. Next, the objective weight and the subjective weight are fused by using the least square method to obtain the comprehensive weight of the evaluation indicator. And insulation health values and insulation health levels of the power transformers are obtained by using fuzzy comprehensive evaluation. Finally, example analysis and comparison are carried out by using the actual operating data of the transformer. Compared with the single principal component analysis method, the correct rate of the comprehensive weighting method of the evaluation indicator proposed in this paper is improved by 5.9%, which is 10.7% higher than that of the single analytic hierarchy process. The results verify the eff ectiveness and practicability of the method proposed in this paper. The proposed method provides a scientifi c basis for the maintenance and overhaul of the transformer. It has a very important practical signifi cance for improving the stability of the power grid and ensuring the normal and orderly progress of the national economy.

Astragalus Polysaccharides Attenuate Ovalbumin-Induced Allergic Rhinitis in Rats by Inhibiting NLRP3 Inflammasome Activation and NOD2-Mediated NF-κB Activation

Jiangtao Xu,Qiong Zhang,Zhaoxin Li,Yuhang Gao,Zhiyu Pang,Yina Wu,Geng Li,Dongyong Lu,Lijuan Zhang,Detang Li 한국식품영양과학회 2021 Journal of medicinal food Vol.24 No.1

Allergic rhinitis (AR) is an IgE-mediated chronic inflammatory disease of the allergic nasal mucosa. It has a significant effect on quality life; most patients with AR also suffer from sleep disorders, mood disorders, and deterioration in social relationships. As increasing numbers of medicinal plants show productive anti-inflammatory activity against inflammatory diseases, there is growing interest in natural medicinal plant ingredients. To this end, we selected Astragalus polysaccharides (APS) to evaluate its anti-inflammatory effect on ovalbumin-induced AR rats, and we further explored its impact on NLRP3 inflammasome activation and NOD2-mediated NF-κB activation. We found that APS can alleviate the nasal symptom of AR rats and attenuate pathological alterations. APS also reduced the inflammatory cytokine levels. APS not only inhibited the NLRP3 inflammasome activation but also inhibited NF-κB activation by decreasing NOD2 expression and blocking the phosphorylation of NF-κB (p65). In conclusion, APS can effectively improve the inflammatory symptoms of nasal mucosa in AR rats, which may be mediated by the inhibition of NLRP3 inflammasome activation and NOD2-mediated NF-κB activation. These findings indicate that APS has the potential to be used as a therapeutic agent for AR.

American ginseng attenuates azoxymethane/dextran sodium sulfate-induced colon carcinogenesis in mice

Chunhao Yu,Xiao-Dong Wen,Zhiyu Zhang,Chun-Feng Zhang,Xiao-Hui Wu,Adiba Martin,Wei Du,Tong-Chuan He,Chong-Zhi Wang,Chun-Su Yuan 고려인삼학회 2015 Journal of Ginseng Research Vol.39 No.3

Background: Colorectal cancer is a leading cause of cancer-related death, and inflammatory bowel disease is a risk factor for this malignancy. We previously reported colon cancer chemoprevention potential using American ginseng (AG) in a xenograft mice model. However, the nude mouse model is not a gutspecific colon carcinogenesis animal model. Methods: In this study, an experimental colitis and colitis-associated colorectal carcinogenesis mouse model, chemically induced by azoxymethane/dextran sodium sulfate (DSS) was established and the effects of oral AG were evaluated. The contents of representative ginseng saponins in the extract were determined. Results: AG significantly reduced experimental colitis measured by the disease activity index scores. This suppression of the experimental colitis was not only evident during DSS treatment, but also very obvious after the cessation of DSS, suggesting that the ginseng significantly promoted recovery from the colitis. Consistent with the anti-inflammation data, we showed that ginseng very significantly attenuated azoxymethane/DSS-induced colon carcinogenesis by reducing the colon tumor number and tumor load. The ginseng also effectively suppressed DSS-induced proinflammatory cytokines activation using an enzyme-linked immunosorbent assay array, in which 12 proinflammatory cytokine levels were assessed, and this effect was supported subsequently by real-time polymerase chain reaction data. Conclusion: AG, as a candidate of botanical-based colon cancer chemoprevention, should be further investigated for its potential clinical utility.

Influence of Wax Lubrication on Cutting Performance of Single-Crystal Silicon in Ultraprecision Microgrooving

Seyed Nader Ameli Kalkhoran,Mehrdad Vahdati,Zhiyu Zhang,Jiwang Yan 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.2

Lubrication can improve the tool-workpiece interface condition in ultraprecision machining, especially in microgrooving processes. The aim of this study was to compare the effects of dry, liquid (cutting oil), solid (wax) and hybrid (cutting oil and wax) lubrication conditions, on the creation of arc-sectioned microgrooves on single-crystal silicon wafers using a singlecrystal diamond tool. Micro cutting forces, chip morphology, and surface quality at different locations of the grooves were investigated. Rose-shaped continuous chips were observed in dry cutting, indicating stable ductile mode material removal. The entrance side of the groove was always smoother than the exit side with a higher degree of phase transformation. Chip adhesions on the tool edge were found in dry and oil lubricated cutting, whereas wax coating could prevent the adhesion. Wax coating played the dual roles of a chip breaker as well as a high-performance lubricant, thus improved the surface integrity. This study demonstrated the capability of using wax coating as an environmentally friendly solid lubricant for microgrooving of single-crystal silicon and possibly for other hard brittle materials.

American ginseng attenuates azoxymethane/dextran sodium sulfate-induced colon carcinogenesis in mice

Chunhao Yu,Xiao-Dong Wen,Zhiyu Zhang,Chun-Feng Zhang,Xiao-Hui Wu,Adiba Martin,Wei Du,Tong-Chuan He,Chong-Zhi Wang,Chun-Su Yuan 고려인삼학회 2015 Journal of Ginseng Research Vol.39 No.1

Background: Colorectal cancer is a leading cause of cancer-related death, and inflammatory bowel diseaseis a risk factor for this malignancy. We previously reported colon cancer chemoprevention potentialusing American ginseng (AG) in a xenograft mice model. However, the nude mouse model is not a gutspecificcolon carcinogenesis animal model. Methods: In this study, an experimental colitis and colitis-associated colorectal carcinogenesis mousemodel, chemically induced by azoxymethane/dextran sodium sulfate (DSS) was established and theeffects of oral AG were evaluated. The contents of representative ginseng saponins in the extract weredetermined. Results: AG significantly reduced experimental colitis measured by the disease activity index scores. Thissuppression of the experimental colitis was not only evident during DSS treatment, but also very obviousafter the cessation of DSS, suggesting that the ginseng significantly promoted recovery from the colitis. Consistent with the anti-inflammation data, we showed that ginseng very significantly attenuatedazoxymethane/DSS-induced colon carcinogenesis by reducing the colon tumor number and tumor load. The ginseng also effectively suppressed DSS-induced proinflammatory cytokines activation using anenzyme-linked immunosorbent assay array, in which 12 proinflammatory cytokine levels were assessed,and this effect was supported subsequently by real-time polymerase chain reaction data. Conclusion: AG, as a candidate of botanical-based colon cancer chemoprevention, should be furtherinvestigated for its potential clinical utility.

Feasibility analysis of using a two-stage nutation drive as joint reducer for industrial robots

Yongwu Cai,Ligang Yao,Jun Zhang,Zhiyu Xie,Jinlong Hong 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.4

Nutation drive claims the advantages of high load capacity, large transmission ratio, desirable stability, low noise, and compact volume, which makes it an excellent alternative to typical joint reducers used in industrial robots. This paper proposes a novel two-stage nutation drive as a joint reducer for the industrial robot. The working principle of the nutation movement is first introduced followed by an analysis of transmission characteristics. The transmission ratio, the transmission efficiency as well as the structural schematic of the proposed nutation drive are presented. Finite element analysis of the main components, including nutation sleeve and bevel gears, was performed. Finally, a prototype was designed, manufactured and tested to verify the feasibility of applying the nutation drive as a joint reducer for industrial robots.