Journal of Jishou University(Natural Sciences Edition)

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25 May 2021, Volume 42 Issue 3

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Mathematics

Proof That n-Dimensional Normally Distributed Linear Functions Obey Normal Distribution

XING Jiasheng, YANG Yichuan, WU Sang

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 1-5.

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A method is given to prove that the n-dimensional normally distributed linear functions obey normal distribution. First, the n-dimensional normally distributed linear function is expressed as the linear function of the n-dimensional standard normal distribution by the transitivity of linear transformation. Then, the linear function of n-dimensional normal distribution is proved to obey normal distribution by using the property that the linear functions of mutually independent normal distribution obey normal distribution.

Existence of Solutions for Boundary Value Problems of Hilfer-Hadamard Type Fractional Differential Equations

DUAN Lijing, XIE Jingli, LIU Hanyan

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 6-12.

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The existence and uniqueness of solutions for a class of three-point boundary value problems of fractional differential equations with Hilfer-Hadamard type fractional derivatives are studied. With Leray-Schauder alternative theorem and Banach fixed point theorem, the results for the existence and uniqueness of solutions for the boundary value problems are obtained.

Existence Theorems for Parabolic Sections of Quadratic Surface

AN Bailing, ZHANG Deyan

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 13-20.

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First, the necessary and sufficient conditions for the existence of parabolic section of a quadratic surface are given according to the parameter equation of the parabola. Secondly, the necessary and sufficient conditions for the existence of parabolic sections, which are parallel to the coordinate plane and the z-axis and intersecting with the z-axis, are given respectively with combining the projection equations of the parabola and its invariant. Finally, the existence problem for parabolic sections of five typical quadratic surfaces is discussed.

Computer and Automation

Design of Real-Time Plant Growing Environment Monitoring System Based on Mobilephone App

LI Deying, QIU Yangfan, YI Tao, XIAO Yiyang

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 21-28.

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In view of the difficulty in monitoring the temperature and humidity of plant growth environment, a remote real-time monitoring system for air temperature and humidity and soil humidity is designed. The system uses stm32f103c8t6 microcontroller as the microprocessor, collects air temperature and humidity and soil humidity through temperature and humidity sensor, and then uploads the collected data to the mobile phone through Wi-Fi module, and transmits the data to the cloud server through the mobile phone App, so as to realize the remote real-time monitoring of environmental temperature and humidity. The simulation results show that the monitoring system has strong real-time performance and high intelligence, which meets the requirements of temperature and humidity control of plant growth environment in agricultural production.

Watermarking Algorithm Based on 3D Wheelbase

TANG Han, CHEN Liuyang, LU Rongbo

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 29-33.

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In order to obtain watermarking with superior robustness and invisibility, a watermarking algorithm based on 3D wheelbase is proposed. Firstly, the watermark image is encrypted by calculating the encryption technology of ghost imaging, then the 3D wheelbase of the image is defined on the basis of 3D histogram, and the set of all pixel points when the wheelbase is maximum is obtained. Finally, the best point in this set is found as the embedding position of the watermark through particle swarm optimization algorithm. Simulation experiments of robustness and invisibility show the effectiveness of the proposed algorithm.

Self-Adaptive and Real-Time Pre-Fall Detection

XIE Jing, YANG Panlong, WEI Xing

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 34-40.

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To detect falls before falling and to provide basis for fall prevention, this study proposes a self adaptive pre-fall detection method that combines SVM and threshold method. Experiment results show that this method has a longer interval time than the artifical threshold and SVM, and has higher recall rate and specificity than SVM. The self-adaptive pre-fall detection method can detect the fall before the fall impact.

Design of Surface Garbage Cleaning Robot

JIANG Xiaoyu, CHEN Jialiang, ZHOU Haolan

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 41-44.

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At present, the pollution of the waters is very serious and is of great concern to the general public. In particular, inland lakes, such as: campuses, community viewing lakes, scenic areas to play with the lake, the prevalence of water garbage difficult to clean up and safety issues. Now the treatment of these surface garbage is basically to take artificial salvage mode, this treatment has great safety risks, and time-and-effort, so the surface garbage cleaning robot came into being. Based on the ardoino uno board as the main control core, this design uses Bluetooth module connection control, including control devices, power units, collection devices and storage devices. The use of conveyor belt to collect garbage instead of the traditional salvage mode, with fast salvage speed, low labor intensity, high efficiency characteristics, and low cost, small size, high efficiency, has a strong practicality.

Physics and Electromechanical

Analysis of Special Structure of Song-Style Second Grade Dovetail Tenon

WANG Jianxing, GAO Ruxin, YANG Duan, HE Jiaxin

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 45-51.

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To better analyze the mechanical properties of the dovetail tenon structure, a twofold line multi-parametric mechanical structure was established, and a mechanical analysis test suitable for wooden structures was carried out. Then, the corresponding dovetail joints were proposed based on the mechanical balance and a deformation coordination relationship formula. The above research results show that the deformation of the dovetail tenon is mainly concentrated around the contact between the tenon and mouth. When the unidirectional load becomes larger, its bending moment also becomes larger, which is easy to cause damage to the contact surface. The load-displacement curve and the ultimate load-vertical load curve obtained through the test also show that when the vertical load increases, the ultimate load also increases; when the ultimate load reaches the yield critical point, the increase in displacement becomes smaller and tends to be smooth.

Application of Monte Carlo Algorithm in Heat Transfer Model of Protective Clothing

LIU Qianlan, LEI Yihui, XIAO Yujiang, DONG Yaling

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 52-56.

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Accurate establishment scientific heat transfer model for thermal protective clothing can reduce the costs and shorten the cycle of research and development. Therefore, a preliminary temperature distribution model is established based on heat conduction principles, and Fourier's law and is modified by retardation factors with controlling parameters. Monte Carlo algorithm is then applied to obtain the relevant parameters in the temperature distribution model according to the experimental data.Finally, an excellent heat transfer model of protective clothing is obtained.

Control Strategy of Variable Frequency Speed Regulation System Based on Multi-Drive

HU Xiaofeng

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 57-62.

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This paper presents a multi drive variable frequency speed control system. The topology of the system is AC-DC-AC structure, and the control performance is AC-AC direct conversion. Zero current commutation strategy and PWM control strategy can get good input current and output voltage waveform, and realize safe commutation. In the following, the correctness of the theory proposed in this paper is proved by the simulation results.

Biology and chemical industry

Landscape Classification of Dehang Scenic Spot in Hunan Province

LIU Bing, XIANG Xiaomei, TAN Lu, CHEN Gongxi

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 63-69.

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This paper aims to identify the landscape characteristics and distribution rules of Dehang Scenic Spot in Hunan Province. By using the aerial map and field survey results, the landscape was classified into different types according to the principle of comprehensiveness, dominant factors and hierarchy. Human disturbance intensity and habitat were used as indicators. The results showed that: (1) The landscape of Dehang Scenic Spot could be divided into 4 landscape classes of 16 landscape types. The natural landscape class contained the most landscape types and distributed widely in the Dehang Scenic Spot, with high plant diversity. The semi-natural class and semi-artificial landscape class were under the intense human disturbance and had low plant diversity, but they had too much relativity with human life. The artificial landscape class mostly presented the regular spatial layout. The Miao nationality wooden architecture was dominant in this class, which embodied the unique national culture of this region. (2) Taking the natural landscape of sun-facing soil slope as the matrix, the landscape types in Dehang Scenic Spot gradually decreased with the widening of the terrain from north to south. Among them, Dehangcun Scenic Area, Donghe Scenic Area and Qiabihe Scenic Area had the most abundant landscape types, but the landscape characteristics of them were quite different. Based on the landscape characteristics and distribution rules of Dehang Scenic Spot, the suggestions were put forward in order to provide a scientific basis for the effective protection and rational use of landscape resources and set the foundation for the study of landscape ecology and the relationship between landscape diversity and plant diversity in this area. Besides, we also hope that this article could provide a new idea and reference case for the selection of classification indicator in the small and medium-scale landscape.

A New Distribution Record of Meehania zheminensis in Wuling Mountain，China

LYU Heng, WANG Benyan, ZHANG Cheng, LIU Qun, ZHANG Daigui

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 70-72.

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Reported a new record of Meehania zheminensis A. Takano, Pan Li & G.-H. Xia, which is similar to Meehania montis-koyae Ohwi a endemic species of Japan. M. zheminensis has been found and identified as M. montis-koyae at first in Zhejiang and Fujian provinces of China, believed M. zheminensis is a new species based more genetic and mor-phological data. This species is a new record of Wuling Mountain and also in Guizhou, Hunan and Hubei Province. All the voucher specimens were preserved in Herbarium of Jishou University (JIU).

Preparation of Li₃V₂(PO₄)₃/C Composite Material Using Acetylene Black as Carbon Source

LIU Saiqiu, JIANG Youliang, ZOU Qiuling, MA Boran, XIANG Yanhong, WU Jianghua, XIONG Lizhi, WU Xianwen

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 73-78.

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In this paper, Li₃V₂(PO₄)₃/C material is successfully prepared by the simple sol-gel method and treated by further calcining. The effect of carbon coating on the morphology, structure and electrochemical performance of the material is comprehensively investigated. It's demonstrated that the monoclinic structure (P21/n) of Li₃V₂(PO₄)₃/C retains complete after carbon coating. The sample with 7 nm coating layer presents excellent crystallinity, which coated by 2 times contents （C20-LVP） of carbon. The electrochemical performance has been improved a lot, with its discharge capacity increasing to 120.3 mAh/g compared with 103.6mAh/g of the sample without carbon coating（C00-LVP）. In addition, a good retention rate of 91% can be obtained, since the discharge ratio can achieve 104.5 mAh/g the after 60 cycles.

Management and Economy

Temporal and Spatial Variation of Grade City Construction in Wuling Mountain Area

ZHANG Jingheng, WU Jilin, ZUO Jinyou, XIAO Yuchun

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 79-86.

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This paper takes the six central cities in Wuling Mountain Area as the research object, constructs the evaluation index system of grade city construction consisting of four grade factors including economy, society, culture and environment and 24 indexes, determines the index weight by entropy weight method, and analyzes the temporal and spatial evolution of grade city construction by TOPSIS and GIS. The results show that in the urban construction of the six central cities in Wuling Mountain Area, the average closeness degree from high to low is: Jishou City, Enshi City, Tongren City, Huaihua City, Qianjiang District, Zhangjiajie City. In terms of time dimension, the urban grade of Enshi City and Huaihua City decreased year by year, while the change of Zhangjiajie City, Jishou City and Qianjiang District was small, and Tongren City improved greatly. In terms of spatial dimension, the pattern of economic, social, cultural and environmental grade is slightly different, and the development pattern of different grade factors is different. The overall grade changes from "high in the central part, low in the two wings" to "high in the northwest, low in the southeast", and finally forms a development pattern of "high in the central part, low in the north and south". Finally, in order to promote the high quality development of the city in Wuling Mountain Area and improve the city grade, the paper puts forward suggestions from four aspects: economic construction, social facilities, cultural strength and ecological environment.

Accurate Demand Analysis and Prediction for New Retail Target Products

LANG Hong, CHANG Xiao, LI Qin, SONG Guofeng

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 87-91.

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Firstly, the factors influencing the sales volume of SKC (Stock Keeping Color) of retail products and their effectiveness are studied with SPSS and R softwares, combined with one-way ANOVA and deep regression analysis. Then, the sales volume of a target subcategory is predicted in grey model with R software, and the accuracy of the prediction data is obtained with Excel software combined with the mean absolute percentage error method. Finally, the prediction model is used to predict the sales and inventory of a target category. The results show that the sales method has a significant effect on the SKC sales volume of retail products; the factors influencing the SKC sales volume of retail products include inventory, discount and selling price; the average absolute percentage error of the target subcategory in each week is mostly less than or equal to 1, and the smallest is 0, which can be considered as a high prediction accuracy of the model. The prediction results of the future sales and inventory of a target subcategory show that the supply of this subcategory is obviously higher than the demand, and the inventory management strategy needs to be adjusted appropriately.

Exploration of TCM Talents Training Model Based on Informationized Knowledge Management System

SHI Ruiwen, LI Hao, GUO Yi, LIU Haigen, CHANG Wenlu, JIN Ximing, TANG Sisi, HU Jianfeng, PENG Cuiling, SHI Xiaoyue

Journal of Jishou University(Natural Sciences Edition), 2021, 42(3): 92-96.

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The cultivation of TCM talents is the "core competitiveness" of the development of TCM hospitals and TCM hospitals in the new era. The modern information knowledge management mode is the use of information technology to deeply explore the tacit knowledge and explicit knowledge of the famouse TCM doctors.Using network storage,system development andthe convenience of resource sharing to explore the training methods of top talents of TCM with wider application, more flexible forms and more operability.