Journal of Jishou University(Natural Sciences Edition)

Relaxed Farkas Lemma for the Sum Optimization Problems

ZENG Zhaohui, WANG Junying, WANG Xianyun

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 1-8.

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By using the properties of the epigraph of the conjugate functions and introducing two new constraint qualifications,the relaxed Farkas lemmas of the sum optimization problems are established.

Stability and Hopf Bifurcation of a Predator-Prey Model with Dual Time-Delay

ZHANG Meiyang, XIE Jingli, GUO Hongli

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 9-17.

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A dual time-delay predator-prey model with B-D functional response and different refuge behaviors is established,and the stability and Hopf bifurcation of the positive equilibrium of the model with different time-delays are analyzed.The research shows that when the time-delay is equal to the corresponding critical value,Hopf bifurcation occurs at the positive equilibrium of the model,and the stability of the positive equilibrium changes.

Properties of Equivalent Sequences and Applications

XU Beining, XU Shaoyuan

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 18-23.

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This article introduces the equivalence relationship in set theory into mathematical analysis,proposes the concept of equivalent sequence,obtains several properties of equivalent sequence,and provides examples to illustrate the applications of equivalent sequences in mathematical analysis,linear algebra,and functional analysis.

Application of an Entangled Chaotic System in Image Encryption

DAI Wenpeng, CHEN Heng, SONG Li, LI Yongxing, HE Na

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 24-34.

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Based on the principle of entanglement chaotic system,a kind of entanglement chaotic system with sinusoidal entanglement term is constructed.The dynamic characteristics of the system,including Lyapunov exponent (LE),bifurcation diagram and power spectrum,are analyzed by MATLAB software.In order to verify the feasibility of the circuit principle,experiments were carried out based on the Multisim circuit simulation software,and the operability of the circuit principle was proved.Finally,the chaotic sequence generated by the system is combined with DNA algorithm to encrypt the image,and the encryption is realized in the sensitive parameter range.The information entropy of the encrypted image is as high as 7.993,the histogram of gray scale is uniform,the correlation between adjacent pixels is low,and the correlation coefficient approaches 0,which shows that the security of the entangled chaotic system is good,the field of image encryption has high application value and high security performance.

Improved Spectrum Sensing Algorithm Based on the Difference of Limit Eigenvalues

TIAN Kun, TAN Zhewen, TAN Yuhao, LEI Kejun, YANG Xi

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 35-39.

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Based on the difference between the maximum and minimum eigenvalues (DMME) of the sample covariance matrix,to improve the setting accuracy of sensing decision threshold,a new method is proposed to calculate the threshold by using the latest results of limiting eigenvalue distribution of Wishart matrix.Compared with the traditional DMME algorithm,the decision threshold setting of the proposed algorithm is more accurate.While improving the reliability of decision results,it improves the detection performance of the algorithm with limited number of samples.Both the theoretical analysis and simulation results verify the effectiveness of the proposed DMME algorithm.

Point-Absorbing Wave Energy Converter Based on Nonlinear Pendulum Stiffness Mechanism

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 40-44.

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In order to achieve stable capture of ocean low-frequency wave energy,a point-absorbing wave energy converter based on a nonlinear pendulum stiffness mechanism was designed.A compact pendulum stiffening device was constructed through addition of simple tensile elastic elements between the pendulums.The force analysis of the nonlinear stiffness structure was carried out the time domain dynamic model of the nonlinear wave energy converter was established based on the Cummins equation,and the wave energy conversion characteristics of the point absorption wave energy converter under the action of regular waves were analyzed.Numerical simulation shows that through introduction of an appropriate nonlinear pendulum stiffness mechanism,the motion response of the system under wave excitation can be improved,and the frequency corresponding to the peak motion response of the system under wave excitation can be reduced,thereby improving the system's capture efficiency of low-frequency energy.

Seismic Performance Analysis of Multi-Span Curved Continuous Girder Bridges Based on Friction Pendulum Spherical Bearings

LI Yue, NING Zhe, YAN Yong, SHAN Honglan, LUO Anran

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 45-55.

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To study the seismic performance and vibration isolation method of multi-span curved continuous girder bridge,a finite element model is established for the multi-span curved continuous girder bridge with friction pendulum spherical bearings,and the dynamic characteristics and nonlinear time analysis is carried out.Results show that the longitudinal stiffness of the bridge model is weaker than the transverse stiffness,and the first-order vibration mode contributes more to the longitudinal seismic response of the bridge pier,and the vibration mode participation coefficient is 29.8%;the sixth-order vibration mode contributes more to the transverse seismic response of the bridge pier,and the vibration mode participation coefficient is 20%;under the E1 earthquake,the friction pendulum spherical bearing can keep the bridge in elastic working condition,and the bearing deformation and expansion joint width meet the requirements,which proves the effectiveness of the selected and arranged friction pendulum spherical bearing;under the E2 earthquake,the maximum bending moment demand of the section of some piers is greater than the bending capacity of the section,but further strength tests were carried out on the piers,and they all meet the seismic demand.

Huajiang Dry-Hot Valley in Central Guizhou Province:Crrent Knowledge and Prespectives

JIA Xinglian, WEI Changsheng, YU Yanghua

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 56-62.

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Situated in central Guizhou Province,China,the Huajiang karst dry-hot valley exhibits a distinctive degree of karst desertification and possesses a relatively fragile habitat.This area's natural environment,ecological industries,and socio-economic factors have drawn considerable scholarly attention.Over the course of nearly 30 years,since the initiation of the "Ninth Five-Year Plan",significant research has been conducted within this region.This research has focused on understanding and controlling karst desertification,enhancing the quality and efficiency of ecological industries,and fostering the coupled development of ecology and economy.Such endeavours have yielded essential theoretical and practical results,aiding in the management of karst desertification and the ecological construction of mountainous regions.This paper delineates the area's fundamental characteristics from four aspects:aridity,high temperatures,valleys,and karst desertification,thereby enriching our understanding of the current habitat situation.Following this,we review the key literature concerning the understanding of karstification and control,cultivation of ecological industries,and improvement in quality and efficiency of these industries from a holistic perspective.Moreover,we utilise long-term cumulative data to analyse areas meriting further investigation.Lastly,based on a regional scale,we suggest future research prospects in three dimensions:quantification and application of micro-habitat characteristics,the interrelationship between vegetation restoration and dual structures,and realisation of the ecological value of ecological products.

Reading Promotion Mechanism of Rural Libraries in Wuling Mountainous Area from the Perspective of Cooperative Governance

WANG Yue'e, LI Shi, LU Shuyi

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 63-66.

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Taking Xiangxi Tujia and Miao Autonomous Prefecture in Wuling mountainous area as an example,this paper analyzes the current situation and existing problems of reading promotion in rural libraries in this region from the perspective of collaborative governance,and constructs the reading promotion mechanism of rural libraries,such as the mechanism of main rights and responsibilities,communication and feedback,resource sharing,supervision and evaluation,qualified staff and so on.

Preliminary Evaluation on the Safety of Volatile Oil of the Alpinia japonica Rhizome in Tujia Medicine

WU Meijing, WANG Zirong, JI Xiushuai, LIANG Yumin, XU Rui, XIANG Lu, XU Taijing, CHEN Xi, XIANG Juan

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 67-73.

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With mice as the experimental subject,the safety of the volatile oil of the Alpinia japonica (Thunb.) Miq Rhizome (AJV) was evaluated through acute toxicity test and subacute toxicity test.The acute toxicity test was divided into the AJV group and control group.The acute toxicity test was conducted with a maximum tolerance dose 5 mL/kg of volatile oil.The subacute toxicity test was divided into low-dose AJV group (1.3 g/kg) and high-dose AJV group (2.6 g/kg) and control group,and the drugs were intragastrically administered once a day for 15 consecutive days.After administration,the physical signs of the mice were observed,body weight and organ coefficient were recorded,the contents of urea nitrogen and creatinine in plasma and the activities of alanine aminotransferase and aspartate aminotransferase in serum were detected,and histopathological examination was performed.The results showed that compared with the control group,the physical signs of most mice were normal after administration,and some mice had vertical hair.There were no significant changes in organ coefficient,urea nitrogen content,creatinine content,alanine aminotransferase activity and aspartate aminotransferase activity of mice (P>0.05).Compared with the weight at the beginning of the experiment,the weight of the mice did not decrease at the end of the experiment.One mouse died in the acute toxicity test.In the subacute toxicity test,the alanine aminotransferase level of 1 mouse significantly increased (135.30 U/L).Pathological findings showed that 1 mouse had liver tissue inflammation and 1 mouse had liver fibrosis.The results indicated that the acute toxicity of volatile oil was low,but it may cause some hepatotoxicity with high dosage in clinic.Attention should be paid to its safety.

Early Catch-up Growth of Preterm Infants with High Nutritional Risk in Xiangxi

HUANG Jun, SHI Lei, LIU Lintao, WU Hongyan, TIAN Yan, TIAN Hongyan

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 74-78.

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To investigate the early catch-up growth of preterm infants with high nutritional risk in Xiangxi.A total of 23 preterm infants with high nutritional risk born from June 2021 to April 2022 in the Children's Health and Rehabilitation Department of Xiangxi Autonomous Prefecture People's Hospital were recruited,and all of them accepted individualized nutrition guidance program.The Z-score method was used to evaluate weight,height and head circumference.The results show that the Z-scores of weight-for-age (WAZ),height-for-age (HAZ) and head circumference-for-age (HCZ) at birth of the 23 preterm infants were significantly less than -2,which were -4.34±0.99,-5.12±1.61 and -4.60±1.62 respectively.The weight,height and head circumference,WAZ,HAZ and HCZ at 3 months and 6 months were significantly higher than those at birth (P<0.001).At 6 months of age,the proportions of WAZ,HAZ and HCZ greater than or equal to -2 were 78.26%,52.17% and 73.91% respectively.This suggests that through the early scientific nutrition guidance,the preterm infants with high nutritional risk will have a rapid physical growth within 6 months after birth.Most preterm infants catch up in weight,head circumference firstly,and then height.

Application of Remimazolam Combined with Esketamine in Pediatric Surgery

FU Yan, ZHAO Cheng, ZHANG Zhimeng, HUANG Dayan

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 79-83.

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In order to explore the application effect of remimazolam combined with esketamine in tonsil or (and) adenoid surgery in children,children who planned to undergo tonsil or (and) adenoid resection were selected as study objects,and were randomly divided into observation group (given remimazolam combined with esketamine) and control group (given propofol combined with sufentanil).The mean arterial pressure,heart rate,FLACC score,Aono score,postoperative coughing,postoperative vomiting,extubation time and propofol addition before extubation were compared between the two groups.The results showed that the mean arterial pressure and heart rate during intubation and 5 min after intubation in observation group were higher than those in control group.The extubation time and the number of propofol addition before extubation in the observation group were significantly less than those in the control group.The FLACC score,Aono score,postoperative agitation rate and postoperative choking rate of the observation group were significantly lower than those of the control group,but the incidence of postoperative nausea and vomiting was not significantly different between the two groups.The application of remimazolam combined with esketamine in tonsillectomy or (and) adenoidectomy in children is effective,has stable hemodynamic characteristics,and helps to reduce the risk of perioperative hypotension,the incidence of postoperative adverse reactions,and further improves the recovery quality of children.

Effect of Multi-Mode Analgesia Combined with Psychological Intervention on Postoperative Delirium in Aged Patients After Femoral Surgery

TANG Xiaohui

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 84-88.

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To explore the effect of multi-mode analgesia combined with personalized psychological intervention on postoperative delirium in aged patients after femoral surgery,80 aged patients with femoral fracture admitted to the Department of Orthopedics of Jishou People's Hospital of Hunan Province from January 2021 to August 2023 were randomly divided into observation group (40 cases) and control group (40 cases).The observation group was given multi-mode analgesia combined with personalized psychological intervention,and the control group was given routine postoperative analgesia.The hemodynamic index at different time after operation,blood gas index on the first day after operation,sleep quality,relief of pain and anxiety,and delirium occurrence in the two groups of patients were observed and analyzed.The results showed that compared with the control group,the patients in the observation group had lower heart rate,lower mean arterial pressure,lower resting and activity pain scores before anesthesia,at the beginning and the end of surgery;on the 1st,3rd and 7th day after surgery,the score of insomnia and the probability of postoperative delirium were lower;the blood gas indexes PaO₂,SaO₂ and OI were higher on the 1st day after surgery;and the differences in the above indexes between the two groups were statistically significant (P<0.05).It can be concluded that the method of multi-mode analgesia combined with individual psychological intervention can play an active role in maintaining the stability of respiration and circulation,improving the postoperative sleep quality,relieving the postoperative pain and anxiety,and promoting the postoperative rapid rehabilitation of the patients,and it can reduce the incidence of postoperative delirium and improve the cognitive function of aged patients,which is an important part of rapid rehabilitation surgery.

Portfolio Optimization Based on an Improved Black-Litterman Model

HUANG Yi, JIANG Wenzheng

Journal of Jishou University(Natural Sciences Edition), 2024, 45(2): 89-96.

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For the "imperfect effectiveness" of financial markets and the "imperfect rationality" of investors,an improved Black-Litterman model combining investor views and multi-channel information is developed by means of the Bayesian framework to determine the optimal personalized investment strategies.In an empirical study of the Chinese stock market,the problem of quantifying investor views is addressed using the SVM-ARIMA-GARCH model.Compared with several reference strategies,the optimal investment strategy identified by the improved Black-Litterman model has a more robust out-of-sample performance,with higher Sharpe ratios and lower turnover ratios in different market conditions.

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