Global strong solutions to the planar compressible magnetohydrodynamic equations with large initial data and vaccum

This paper considers the initial boundary problem to the planar compressible magnetohydrodynamic equations with large initial data and vacuum. The global existence and uniqueness of large strong solutions are established when the heat conductivity coefficient $\kappa(\theta)$ satisfies \begin{equation*} C_{1}(1+\theta^q)\leq \kappa(\theta)\leq C_2(1+\theta^q) \end{equation*} for some constants $q>0$, and $C_1,C_2>0$.Comment: 19pages,some typos are correcte

Optimization of extraction process and structural characterization of polysaccharides from Cornus officinalis

Objective: This study aimed to optimize the microwave assisted aqueous two-phase extraction (MATPE) process of polysaccharides from Cornus officinalis and obtain a uniform polysaccharide fraction. Methods: The best extraction technology was determined through an orthogonal experiment. To obtain a uniform polysaccharides fraction (COP-2-S), the crude extract of C. officinalis polysaccharides was purified using DEAE-52 cellulose and Sephadex G-100 column chromatography. The molecular weight of COP-2-S was determined by high performance gel permeation chromatography. The monosaccharide composition of COP-2-S was determined by gas chromatography. The structure of COP-2-S was characterized by UV, and IR spectra, and a scanning electron microscope. Results: The optimal MATPE process of polysaccharides from C. officinalis was as follows: microwave power of 300 W, ethanol volume fraction of 35%, ammonium sulfate mass fraction of 22%, a solid-to-liquid ratio of 1∶20 (g/mL), and the yield of polysaccharides from C. officinalis was (12.04±0.17)%. The molecular weight of COP-2-S was 17 450 Da. The molar ratio of arabinose, glucose, and galactose that made up the monosaccharide was 12.85∶30.71∶18.09. Conclusion: COP-2-S had no characteristic absorption at 260 nm and 280 nm. Besides, COP-2-S had typical infrared absorption characteristics of polysaccharides

Combination of Chinese herbal medicine and conventional western medicine for coronavirus disease 2019: a systematic review and meta-analysis

ObjectiveThis study aimed to assess the efficacy and safety of Chinese herbal medicine (CHM) plus conventional western medicine (CWM) in comparison with CWM against COVID-19.MethodsWe searched eight electronic databases and three trial registers spanning from January 1, 2020 to May 18, 2023. We included randomized controlled trials (RCTs) comparing the effectiveness and safety of CHM plus CWM and CWM against COVID-19 in our study. The Cochrane Risk of Bias tool 2.0 (RoB2) was applied to evaluate the methodological quality of the included RCTs. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system was employed to assess the certainty of evidence. Statistical analysis was implemented in R version 4.1.2.ResultsOur study included 50 RCTs involving 11,624 patients. In comparison with sole CWM, CHM plus CWM against COVID-19 significantly enhanced clinical effective rate (RR = 1.18, 95% CI [1.13, 1.22]), improved chest image (RR = 1.19, 95% CI [1.11, 1.28]), inhibited clinical deterioration (RR = 0.45, 95% CI [0.33, 0.60]), lowered mortality (RR = 0.53, 95% CI [0.40, 0.70]), and reduced the total score of TCM syndrome (SMD = −1.24, 95% CI [−1.82, −0.66]). SARS-CoV-2 nucleic acid conversion time (MD = −2.66, 95% CI [−3.88, −1.44]), duration of hospitalization (MD = −2.36, 95% CI [−3.89, −0.82]), and clinical symptom (fever, cough, fatigue, and shortness of breath) recovery times were shorter in CHM plus CWM groups than in CWM groups. Further, CHM plus CWM treatment was more conducive for some laboratory indicators returning to normal levels. No statistical difference was found in the incidence of total adverse reactions between the two groups (RR = 0.97, 95% CI [0.88, 1.07]). We assessed the risk of bias for 246 outcomes, and categorized 55 into “low risk”, 151 into “some concerns”, and 40 into “high risk”. Overall, the certainty of the evidence ranged from moderate to very low.ConclusionsPotentially, CHM listed in this study, as an adjunctive therapy, combining with CWM is an effective and safe therapy mode for COVID-19. However, more high-quality RCTs are needed to draw more accurate conclusions.Clinical trial registrationhttps://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=293963

Interval State Estimation of Linear Multicellular Systems

Linear multicellular system is a type of differential inclusion system, which can be deemed as an extension of linear control system with set-valued mapping. As an important issue in existing control systems, interval state estimation has been widely applied in engineering practices. Over the years, the objects of the studies on interval state estimation have been extended from the initial linear time-invariant systems to linear time-varying systems, chaotic systems, feedback linearization systems, and nonlinear Lipschitz systems. However, there is no report on the design of interval observer for linear multicellular system. To make up for this gap, this chapter attempts to explore the design of an interval observer for linear multicellular systems

Research on Management of Ecotourism Based on Economic Models

Conference Name:International Conference on Energy, Environment and Development (ICEED). Conference Address: Kuala Lumpur, MALAYSIA. Time:DEC 08-09, 2010.This paper analyzes the problems of ecotourism and proposes some suggestions according to the behaviors of travel agency, tourist and eco-scenic spot. From a macro perspective, the government should tax the eco-scenic spots in order to solve the externalities of ecotourism. Establishing the return model between the travel agency and eco-scenic spot is useful to restrict travel agency behavior. This paper constructs the ecotourism models based on capital and tax aiming at harmonious development and proposes a series of recommendations for the government and eco-scenic spots. (C) 2011 Published by Elsevier Ltd. Selection and peer-review under responsibility of RIUD

An Optimization Method of Multiclass Price Railway Passenger Transport Ticket Allocation under High Passenger Demand

The development of high-speed railways (HSR) in China has attracted a large number of passengers from highway and aviation to railways due to their comfort and high speed. In this case, HSR passenger transportation can improve the operating income by optimizing the ticket allocation. Here, we propose an optimization method of multiclass price railway passenger transport ticket allocation under high passenger demand. First, for the “censored data” problem in the railway passenger demand forecast, we constructed an unconstrained model of railway passenger demand and solved the unconstrained demand through an expectation-maximization algorithm. Then, on this basis, we use gray neural networks (GNNs) to predict the passenger demand of different origins and destinations (ODs), and according to the prediction results, we propose two ticket allocation methods based on operation and capacity control: accurate predivided model and fuzzy predivided model. And we solve this problem by constructing a particle swarm optimization algorithm. Lastly, we use examples to prove that the proposed ticket allocation method can meet the passengers’ needs and have good economic benefits

Determinants and Outcomes of Relationship Quality: An Empirical Investigation on the Chinese Travel Industry

This study investigates the determinants and outcomes of relationship quality in the context of the Chinese travel industry. A conceptual model was developed and tested to identify the determinants and outcomes of relationship quality. Partial least squares analyses on the survey data show that five of six proposed predictors have significant influence on relationship quality, and a higher level of relationship quality results in better reputation and stronger customer loyalty. The findings will provide travel agency managers with guidelines to develop and implement effective marketing strategies in the Chinese tourism market

Development and Experiment of Semi-Physical Simulation Platform for Space Manipulator

To address the extended development cycle, high costs, and maintenance difficulties associated with existing microgravity simulation methods, this study has developed a semi-physical simulation platform for robotic arms tailored to different gravity environments and loading conditions. The platform represents difficult-to-model joints as physical objects, while the easily modeled components are simulated based on principles of similarity. In response to the strong coupling, nonlinearity, and excess force disturbance issues in the electric variable load loading system, a fractional-order linear active disturbance rejection control algorithm was employed. The controller parameters were tuned using an improved particle swarm algorithm with modified weight coefficients, and experimental results demonstrate that a fractional-order linear active disturbance rejection control improves response speed and disturbance rejection performance compared to linear sliding mode control. The study investigated the differences in the drive force of joint motors in space robotic arms under varying gravity environments and loading conditions. Experimental results indicate that load torque is the primary influencing factor on joint motor drive force, while radial force serves as a secondary influencing factor. Additionally, when the axis of the joint motor is perpendicular to the ground, it can, to some extent, simulate microgravity conditions on the ground