Table of Content

    25 November 2020, Volume 41 Issue 6
    Mathematics
    Number of 1-Factors in Three Types of 3-Regular Graph
    TANG Baoxiang, REN Han
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  1-4. 
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    Three types of 3-regular graphs are constructed, and the calculation formulas for the number of 1-factors of these three types of graphs are given by the method of classification and summation.
    Solution of Isochronous Curve Problem
    XING Jiasheng, WU Sang
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  5-10. 
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    For the solution of isochronal curves with a given isochronal time function and the formula of time for particle to slide down from a certain height along the smooth curve, the problem is transformed into an integral equation solution problem and  Abel transformation is performed for the integral equation. Integral order conversion method is applied to obtian the solution formula, and the solution of the isochronous descent problem is proved out an inverted cycloid.
    On a Strengthened Half-Discrete Hilbert-Type Inequality Related to the Riemann Zeta Function
    NIE Caiyun
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  11-14. 
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    With weight function, Hermite-Hadamard’s inequality, and a strengthened Hlder inequality, a half-discrete Hilbert-type inequality in the whole plane with the kernel of hyperbolic cotangent function and multi-parameters is improved. Some new inequalities are built.
    Fréchet Subdifferentials of the Value Function for Parametrized Composite DC Optimization Problems
    XIAO Chengfeng, HU Lingli
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  15-20. 
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    By using the properties of subdifferentials, we introduce a new weaker constraint qualification. Under this constraint qualification, we establish the upper estimates for the Fréchet subdifferential of the value function for the parametrized DC composite optimization problems.
    Computer
    An Watermarking Algorithm Against Cropping Attack Based on SVD and DCT
    YU Shuaizhen, ZHOU Jian, XIE Daoping
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  21-27. 
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    In order to improve the anti-attack capability  of watermarking system against cropping attack, this paper presents an anti-cropping watermarking algorithm based on multi-transform domain. The DCT transform is carried out on each segmentation region of the host image and the maximum coefficients of each segmentation region are extracted to form a new matrix. The encrypted watermark information is then embedded into the singular value transformation domain of this matrix. Experiments show that the algorithm can not only fully resist the single cropping attack, it also has  strong resistance to the joint attack of conventional image processing and local cropping. Even after multiple joint geometric attacks, it can still extract clear watermarks.
    Time Series Transformation Algorithms Based on Complex Networks
    HE Maoyu, ZHOU Yin, ZHOU Jingxi, SHEN Li
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  28-31. 
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    To improve classic visibility algorithm of transformation from time series to complex networks, this paper proposes maximum value split algorithm and convex hull algorithm and applies them in the fractal Brown time series respectively. Experimental results show that improved algorithm can reduce time complexity remarkably.
    Electronics and Electricians
    Simulation of IC Bus Technology Based on Proteus
    XIANG Jiwen
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  32-36. 
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    The hardware connection and data transmission protocol of IC bus are studied, and a simulation circuit with three IC memories is designed. The main controller adopts single chip microcomputer and the control program is written in assembly language. Proteus  simulation test shows that the result is correct.
    Control Strategy of Induction Wind Power Generator System with Full Rated Inverter
    PAN Liqiang, LI Juan, YANG Gaocai, YU Hu, HOU Yiling, XU Binkun
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  37-44. 
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    For smooth operation of the power system regardless of the various wind speed and system ground faults, the full rated inverter is applied in wind generator. This inverter has double loop control on both grid side and generator side. It is note that the voltage closed-loop control as an innovative use is attributed for grid side control. The pitch angle controller is designed to meet both various wind and system faults according to the input signal. Simulations for evaluated the performance are conducted and the results verify that the proposed control strategy with the high efficiency satisfies requirements both WT control and the quality of the power grid.
    Dynamics
    Determination of the Threshold Temperature of Physical and Mechanical Properties of Sandstone Post High Temperature by Machine Learning Algorithm
    LONG Qinyuan, MEI Gang, TIAN Hong, XU Nengxiong
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  45-50. 
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    In this paper, machine learning algorithm is adopted to determine the threshold temperature of physical and mechanical properties changes of sandstone post high temperature. Based on Python language, SVM and K-means algorithm are employed to classify and cluster sample data, determine the threshold temperature range, and verify the rationality and accuracy of dichotomies. The results show that 1) the threshold temperature range of the sandstone sample is 400 ℃ ~ 600 ℃; 2) there are significant differences on the physical and mechanical properties of the sandstone around the threshold temperature. The physical and mechanical properties of the rock samples are relatively scattered below the threshold temperature range, while the physical and mechanical properties of the rock samples are relatively concentrated above the threshold temperature range.
    Transportation
    Transient Dynamic Response of Frame Bridge to Train at Different Speeds
    WANG Jianxing, Minabai·Maimaitituerxun, HUANG Yilong
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  51-55. 
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    With an ordinary concrete frame bridge project as the research object, a numerical model of concrete frame bridge was established with the solid element Solid65 in the finite element analysis software. The deflection-time curve of the mid-span joints of the frame bridge was obtained through transient dynamic calculation and analysis of the complete method, which  reflected the dynamic response characteristics, the displacement characteristics of the frame bridge when the train  passed through the frame bridge at different speeds. The analysis results  showed that 120~150 km/h was the optimal speed interval for the train to  pass through the frame bridge. At this speed interval, the dynamic deflection time-history curve of the frame bridge  tended to be flat, and the maximum deformation of the bridge body  was 1.88×10-2mm which  occurred near the mid-span  before and after the train  passed through the mid-span.
    Simulation of Insulator Contamination Characteristics Based on CFD
    CHEN Guangsi, NIU Yibo, XI Yun
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  56-60. 
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    In order to study the contamination characteristics of insulator at different voltages, the wind flow field and electric field in sandstorm were simulated based on fluid mechanics theory and electric field theory. The research shows that contamination of insulator is different at different voltages. When the flow velocity around the insulator is small, the voltage at both ends of the insulator increases, which will lead to the increase of the contamination quantity, and the contamination is closely related to the change of electric field force. When the surrounding flow velocity is large, even if the voltage increases, the contamination quantity will not change too much.
    Chemistry
    Hyperbranched Polytriazole Solid Polyelectrolyte and Its Li-Ion and Zinc-Ion Conductivity
    OU Xiaoying, LIU Ben, WU Jianhua, PENG Xiaochun
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  61-69. 
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    Hyperbranched polymer with rigid structure usually have good solubility, low viscosity and outstanding mechanical properties, which could be used to prepare solid electrolyte. Hyperbranched polytriazole (hb-GPTA) was synthesized due to azide-acetylene click chemistry reaction of alkynyl-based monomer M1 and azido-contained monomer M2 with catalysis by Cu(I). The hb-GPTA exhibited good solubility, film formation property, and thermostability (the thermal decomposition temperature is 35 ℃). The hb-GPTA was doped with LiTFSI and Zn(OTf)2 respectively to prepare solid electrolytes whose electrochemical properties were characterized. The results demonstrated that LiTFSI doped polymer had higher conductivity of 3.27×10-5 S/cm and the electrochemical window is 5.2 V, while the Zn(OTf)2 doped polymer exhibited lower conductivity of 4.20×10-7 S/cm but remained stable within the voltage range of -1~ 6V. It could be inferred that polymer with triazole has potential application value in making zinc batteries together with electrochemical stability analysis.
    Characteristic column:Study on Wuling Mountain Area
    Prediction of Cultivated Land Quantity in Yongding District, Zhangjiajie
    CHEN Ming, XIE Huan, PENG Xinzhu, ZHOU Yajin, TAN Yunxian, ZHUANG Dachun
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  70-73. 
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    Taking Yongding District, Zhangjiajie as an example, based on the analysis of the current characteristics of  cultivated land utilization and the dynamic changes, the paper defines  three objectives of reserving  cultivated land, namely food security, economic security and ecological security. Using the methods of food security method, supply-demand balance and trend extrapolation method to predict the prospective cultivated land quantity under the single target restriction in 2020,2030 and 2035, the Analytic Hierarchy Process (AHP) is used to assign the weights of the prediction results, and a multi-objective combined model is established. The total cultivated land tenure in Yongding District in 2020,2030 and 2035 is 30 423.35,29 515.76,29 321.66 8hm respectively. This indicates that the overall trend of reduction of cultivated land  is decreasing.
    Sports
    Problems and Innovative Development Path of Wuhan Marathon
    LI Li
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  74-79. 
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    This paper studies the problems of Wuhan marathon. The results show that the number of participants in Wuhan marathon needs to be expanded, the event items and activities content are relatively single; the air quality needs to be further improved; the financing channel of the event is single; and the derivatives of the event are not rich. On the basis of these, the paper puts forward some suggestions, such as strengthening the supply side reform of the event, enriching the event and activity content, strengthening the management and monitoring of air quality, strengthening the commercial awareness, broadening the source of competition funds, and building a complete industrial system of events.
    Economics
    A Review of Chinese Agricultural Product Brand Based on Mapping Knowledge Domains
    SHI Xiaochun, WEN Hao, WANG Jingjing, CHEN Chen
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  80-90. 
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    Based on the relevant theories of mapping knowledge domain, the literature concerning Chinese agricultural product brands realized visible analysis by CiteSpace software and the hot element, evolution process and trend of agricultural product brands research were analyzied by Netdraw software which described The results illustrated that the focuses were brands attribute structure and effectiveness, brand evaluation, brand constructin. The evolution path of the research content reflects the characteristics of different stages, which conforms to the adjustment of national policies and changes of economic and social development. There are few scholars and institutions specializing in agricultural products bands research. The close cooperation was not set up among these scholars and institutes. Future research should further improve the basic theory and research method of agricultural products brand, expand the depth and breadth of agricultural products brand research, and establish a close academic research network.
    Characteristics  of Tourism Economic Difference and Influencing Factors in Hunan Province
    TANG Yexi, LI Zhihui, ZHOU Shengfang, ZUO Xin, DENG Mingrong
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  91-96. 
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    Taking 14 prefecture-level cities (prefectures) in Hunan Province as the research objects, using SPSS software to calculate the standard deviation, coefficient of variation, Gini coefficient and nich index, the characteristics and influencing factors of the difference in tourism economy in Hunan Province from 2009 to 2018 are analyzed.The results show that the difference in tourism economy of various cities (prefectures) in Hunan Province is gradually shrinking; the pattern of convergence and dispersion of the inbound tourism economy is more significant; the level of socio-economic development and tourism resources are the main factors affecting the difference in tourism economy.
    Editology
    Arrangement Improvement on Level Table of Orthogonal Test Factor#br#
    WANG Saiqun, YIN Xiaohong
    Journal of Jishou University(Natural Sciences Edition), 2020, 41(6):  97-100. 
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    According to the investigation, it is found that there are some problems in the arrangement of the orthogonal test factor level table in the literature, such as the inaccurate table title, the Irregular Arrangement Format of the Item Column Information, the wrong column in the first column from the left, the relationship between the column and the table data does not conform to the requirement of uniformity, the factor symbol is regarded as the quantity symbol and arranged in Italics, etc. . In view of the above problems, some suggestions are put forward: taking "the level of the factors" as the table title; using parentheses to indicate the coincident relationship of the factors and their symbols, i. e. , arranging them in the form of "temperature (a) " ; Change the column "factor" to "level" ; the factors are listed correctly; the rest are arranged according to the table routine. The method accords with the editing and proofreading standard, greatly simplifies the form design, and provides reference for the standard layout of the table in books and periodicals.
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