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Table of Content

      
    20 January 2022
    Volume 57 Issue 1
    Comparision of the intestinal microflora diversity of four species of abalone
    GUO Zhan-sheng, ZHANG Hai-tao, HOU Xu-guang
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2022, 57(1):  1-7.  doi:10.6040/j.issn.1671-9352.0.2021.323
    Abstract ( 1190 )   PDF (3930KB) ( 237 )   Save
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    The composition and diversity of intestinal microflora of Haliotis discus hannai, H. iris, H. rubra and the hybrid abalone(H. discus hannai ♀×H. iris ♂)were investigated using 16S rRNA high-throughput sequencing technology. The results showed that the OTU number, the values of Shannon index and Chao1 index were the highest in H. iris, and the lowest in H. rubra. The dominant phyla in the intestines of the four abalone species were Proteobacteria, Fusobacteria and Tenericutes, accounting for 61.93% to 95.78%. Among them, the absolute dominant phylum in H. discus hannai, H. iris and hybrid abalone was Proteobacteria, while that in H. rubra was Tenericutes. Psychrilyobacter, Vibrio and Mycoplasma were the predominant genera of the intestinal tract of the four species of abalone, accounting for 39.70% to 53.65%. 175 OTUs belong to the core microflora were detected in four species of abalone, a total of 11 OTUs have been found that the relative abundance exceeded 1%. Both Anosim and Adonis analyses found that the intestinal microflora differed significantly between hybrid abalone and H. rubra, hybrid abalone and H. iris, and H. discus hannai and H. rubra(P<0.05); LefSe was used to analyze the differences of microbial taxon composition among abalones and seven biomarkers were identified, including six biomarkers in H. iris and one in hybrid abalone.
    Characteristics of soil and vegetation during natural restoration process in abandoned quarry
    SONG Bai-min, LIU Jian, ZHANG Yu-hu, WANG Ren-qing
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2022, 57(1):  8-19.  doi:10.6040/j.issn.1671-9352.0.2021.393
    Abstract ( 788 )   PDF (898KB) ( 192 )   Save
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    Adopted the method of the space series to represent the time series, soil physical and chemical properties, plant community species composition, community characteristics and their relationships with soil properties were comparative analyzed at four different successional stages of typical abandoned quarries in Miaofengshan, Beijing, including 1, 5, 15, 32-year and one control plot without quarrying influence at least more than 50 years. The results showed that at the initial stage of natural recovery, soil fertility was extremely low and there was a serious lack of total N and organic matter. The plant species composition was simple, mainly contain Eleusine indica and Eragrostis pilosa. With the process of natural ecological restoration, soil physical and chemical properties gradually improved. Soil organic matter continuously accumulated and soil nutrients showed an increasing trend. Soil particle size and soil bulk density decreased gradually. From the view of dominance, at different succession stages, the dominant species in community continuously changed slowly and the replacement of dominant species was obvious. At 5 years and 15 years plots, Chloris virgata and Setaria viridis were the same dominant species. As succession proceeded to 32 years, the dominant species in community were replaced by shrub(Vitex negundo var. heterophylla), Arthraxon hispidus and Cleistogenes chinensis which were similar to the dominant species in the control plots over 50 years. Jaccard coefficient indicated that the community similarity in 32-year plots have reached a moderately similar level compared to that of in the control plots.With the process of community succession, the total vegetation coverage and aboveground biomass exhibited increasing trends, and the species diversity and richness of species gradually increased and then remained relatively stable after 32 years of succession. In the process of natural ecological restoration, the changes of soil physical and chemical properties correspond to the dynamics of community structure. Our study showed that the process of natural ecological restoration was essentially a co-evolution process of soil-vegetation system. The initial restoration achieved to control plot in the abandoned quarry of Beijing Western Mountain rely on natural power, but the process was slower. In order to accelerate the process of ecological recovery, artificial assistance was necessary.
    Reliability analysis of road transportation system of hazardous chemicals tank truck based on fault tree and Bayesian network
    CAO Run-feng, LIU Rui-xian, LIU Jing
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2022, 57(1):  20-29.  doi:10.6040/j.issn.1671-9352.0.2020.338
    Abstract ( 782 )   PDF (1007KB) ( 404 )   Save
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    In order to ensure the reliability of the road transportation system of hazardous chemicals tank truck, a system reliability research method based on fault tree analysis and Bayesian network is proposed. Firstly, the Bayesian network model and conditional probability table according to the method of converting the fault tree model of the road transportation system to the Bayesian network was determined. Secondly, the Bayesian network two-way reasoning algorithm to perform inference calculations on the road transportation system of hazardous chemicals was combined. Finally, the reliability of the road transportation system of hazardous chemical tank trucks was analyzed. The research found that this method can forward infer the possibility of system failure based on the prior probability of root node failure, and can troubleshoot the failure through the results of the probability importance analysis of the root node, and calculate the posterior probability of the root node through reverse reasoning diagnose the fault. In the conclusion, the countermeasures against key risk events in the system are proposed.
    Green supply chain pricing and coordination with reciprocal preferences under government subsidies
    ZHANG Ke-yong, ZHANG Na
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2022, 57(1):  30-41.  doi:10.6040/j.issn.1671-9352.0.2020.426
    Abstract ( 788 )   PDF (3950KB) ( 249 )   Save
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    In the green supply chain, both the government green innovation subsidies and the member reciprocal preferences behavior are considered, 4 Stackelberg game models are established such as a centralized decision model, a model based on both manufacturer and retailer without reciprocal preference, a model based on a manufacturer with reciprocal preference and a model based on a retailer with reciprocal preference. The model analysis reveals that the reciprocal behavior of manufacturer under government subsidies has a positive effect on the improvement of product greenness, and helps to improve the overall utility of the green supply chain and social welfare. Government subsidy strategy has a negative effect on members reciprocal preference behavior. The reciprocal preference of the retailer will adversely hinder the development of the green supply chain, but the reduction of the proportion of the government green innovation subsidies could weaken the negative effects of retailers reciprocal preference behavior on the utility of the green supply chain, and promote the economy and sociality of system. Finally, the cost sharing-benefit sharing contract is established to coordinate the green supply chain and verified by numerical simulation.
    Multiple stability switches and Hopf bifurcation in a time-delay predator-prey system
    SHEN Wei, ZHANG Cun-hua
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2022, 57(1):  42-49.  doi:10.6040/j.issn.1671-9352.0.2021.344
    Abstract ( 596 )   PDF (5522KB) ( 317 )   Save
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    A time-delay predator-prey model with Holling type Ⅲ functional response is consider. The stability and Hopf bifurcation of the positive equilibrium point of the model are studied by analyzing the distribution of the roots of the corresponding characteristic equation on the complex plane. Finally, the corresponding theoretical results are verified by MATLAB software package.
    Properties of the species invasion model with Allee effect
    ZHANG Bei-bei, XU Yao, ZHOU You, LING Zhi
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2022, 57(1):  50-55.  doi:10.6040/j.issn.1671-9352.0.2021.259
    Abstract ( 1211 )   PDF (1782KB) ( 736 )   Save
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    Based on the reaction diffusion equation with free boundary, the mathematical model of species invasion with Allee effect is established, the dynamic process of the invasive species is described, and the existence and uniqueness of the global solution of the model are explored. Focusing on the nature of the long-term solution, the corresponding conditions of the spreading or vanishing of the invasive species in the new environment are obtained, we have proved the conclusion that the possibility the specie will be vanish due to the small initial survival area or poor self-spreading ability, and verified our analytical findings numerically with MATLAB software. These results provide a theoretical basis for the prevention and control of ecological protection and harmful species invasion.
    An SEAIR model with relapse effect and its application in COVID-19 transmission
    ZHANG Yu-qian, ZHANG Tai-lei
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2022, 57(1):  56-68.  doi:10.6040/j.issn.1671-9352.0.2021.054
    Abstract ( 1016 )   PDF (2285KB) ( 376 )   Save
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    In this paper, an SEAIR epidemic model with relapse and asymptomatic infection is established, and the basic reproduction number R0 is given. It is proved that the disease-free equilibrium is globally asymptotically stable when R0<1, the disease-free equilibrium is unstable and the disease is uniformly persistent when R0>1. As an application of the model, the cumulative number of COVID-19 cases reported in Hubei province is selected in this study. The model is fitted with reported data and simulated the development trend of the disease. Finally, the sensitivity of the parameters is analyzed, and the effect of different relapse rates on the COVID-19 is studied. The results show that the higher the relapse rates, the more serious the COVID-19 will be. The findings suggest that strict quarantine measures and wearing masks are recommended to reduce the infection rates of the disease and reduce the relapse rates of the disease.
    Optimal control for competing species with diffusion and size-structure
    LI Na, LUO Zhi-xue
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2022, 57(1):  69-76.  doi:10.6040/j.issn.1671-9352.0.2021.223
    Abstract ( 596 )   PDF (434KB) ( 237 )   Save
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    The optimal control of a competitive population system with diffusion and size-structure is studied. Firstly, the existence and uniqueness of non-negative solution are obtained by comparison principle and the fixed point theorem. Secondly, Mazur theorem is used to prove the existence of optimal control. Finally, the optimality conditions are given by means of the normal cone definition and an adjoint system.
    Optimal harvesting for three species system with size-structures in periodic environments
    ZHANG Hao, LUO Zhi-xue, ZHENG Xiu-juan
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2022, 57(1):  77-88.  doi:10.6040/j.issn.1671-9352.0.2021.355
    Abstract ( 538 )   PDF (497KB) ( 242 )   Save
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    The paper investigates the optimal harvesting for three-dimensional food chain model with size-structures in periodic environments. Firstly, by applying the theorem of Banach fixed point, we establish the existence and uniqueness of nonnegative bounded solutions. Secondly, we obtain the necessary conditions by using the tangent-normal cones. Finally, on the basis of Ekelands variational principle, we conclude that a unique optimal policy exists.
    Asymptotic behavior for a class of higher-order Camassa-Holm equations
    YU Ye, WANG Hai-quan
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2022, 57(1):  89-94.  doi:10.6040/j.issn.1671-9352.0.2021.007
    Abstract ( 494 )   PDF (358KB) ( 279 )   Save
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    The Cauchy problem, associated with a class of higher-order Camassa-Holm equations which can be regarded as a generalization of Camassa-Holm equation, is shown. The long-time behavior of the solutions for this problem is discussed. It is proved that the algebraic decay exponent of the solutions u(x,t) at infinity is the same as that of the initial value data when |x| tends to infinity and the initial value data are algebraic decay.
    Lifetime behavior of the open censored δ shock model with multiple Bernoulli arrival
    JIANG Wei-xin, MA Ming, LIU Hua
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2022, 57(1):  95-100.  doi:10.6040/j.issn.1671-9352.0.2020.365
    Abstract ( 635 )   PDF (890KB) ( 196 )   Save
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    A new censored δ shock model is studied, and the lifetime properties of the discrete open censored δ shock model with renew intervals following non-negative geometric distribution are discussed. In the case of any critical failure value, the lifetime distribution, average lifetime, reliability function and failure rate function of the system are obtained. In order to make the results more intuitive, the relationship between average life and some special parameters is analyzed by using figure and table.
    Waveform relaxation methods for fractional stochastic delay differential equations
    WANG Miao-miao, DING Xiao-li, LI Jia-min
    JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2022, 57(1):  101-110.  doi:10.6040/j.issn.1671-9352.0.2021.225
    Abstract ( 592 )   PDF (1490KB) ( 478 )   Save
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    The waveform relaxation method for fractional stochastic delay differential equations is studied. Under the Lipschitz condition of splitting function, the error estimate of waveform relaxation method is given. The error estimate shows that the method is convergent in mean square sense. Finally, several numerical examples are given to show the effectiveness of the waveform relaxation method for solving fractional stochastic delay differential equations, and the correctness of the convergence theory is verified.