28 April 2025, Volume 24 Issue 2
    

  • Select all
    |
  • LI Jie, ZHANG Ge, CHEN Xiao-liang, LIN Xu-dan
    Journal of Guangzhou University(Natural Science Edition). 2025, 24(2): 1-13.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    People′s health is the foundation of social civilization and progress, and an important symbol of national prosperity and strength. The Party and the country prioritize the people′s health in their strategic development, proposing the ″Healthy China″ strategy. In August 2016, the Political Bureau of the CPC Central Committee held a meeting to review and adopt The Outline of the Healthy China 2030 Plan, which has made institutional arrangements to better protect people′s health at present and in the future. However, there is still a lack of theoretical interpretation and practical research on the construction of a Healthy China from a geographical perspective. From the perspective of Chinese traditional culture, this paper puts forward the basic connotation of Healthy China construction, takes man-land relationship, spatial analysis and regionalization theory as the core theoretical basis of geography serving Healthy China construction. Based on the outline of the Healthy China 2030 Plan, an evaluation index system for the construction of Healthy China has been established with reference to the health evaluation indicators formulated by the World Health Organization, including five dimensions: health status, health risk, health service, health system and healthy life. Based on this, the progress of Healthy China construction in China is evaluated in accordance with the Sustainable Development Goals of the United Nations, and a geographical path of Healthy China construction is explored. This study has a positive significance for the planning of Healthy China according to local conditions, fully reflecting the scientificity, rationality and fairness of the construction, and provides a scientific basis for China to complete the goals of the program within the specified time, achieve the United Nations Sustainable Development Goals and the requirements of the World Health Organization, and realize the general goal of comprehensively improving the health of the people.
  • KONG Ling-cai, REN Liu-yi, MENG Hong, NIU Ya-ru, ZHENG Xin-cao, LIU Jing-gang
    Journal of Guangzhou University(Natural Science Edition). 2025, 24(2): 14-23.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The Tiered Medical Treatment System (TMTS) plays a pivotal role in exploring the implementation pathways of the Healthy China strategy. Under TMTS, the patterns of residents seeking medical care can be categorized into three types: receiving effective treatment at primary healthcare institutions; undergoing initial diagnosis at primary healthcare institutions but requiring referral to higher-level hospitals; or directly choosing higher-level medical facilities for treatment. To achieve a comprehensive consideration of these three patterns, this study introduces two parameters, the primary healthcare rate (α) and referral rate (β), based on a two-step floating catchment area method. Taking Guangzhou city as a case study, this research investigates residents′ patterns of seeking medical care under TMTS and their impact on spatial accessibility to healthcare services, aiming to provide references for optimizing medical resource allocation. The results indicate that when the primary healthcare rate α=0, overall medical accessibility is the worst; however, when α=0.1 and β=0.05, overall medical accessibility reaches its highest level. Under a fixed primary healthcare rate α, lower referral rates contribute to higher overall accessibility. Overall, residents′ medical accessibility in Guangzhou′s districts exhibits a multi-layered spatial pattern centered on the main urban area and decreasing outward toward peripheral areas. The study finds that the TMTS improves the utilization rates of healthcare institutions at all levels and enhances the accessibility and convenience for residents seeking medical care. Additionally, this system contributes to promoting the equitable allocation of medical resources. These findings provide crucial theoretical support and policy recommendations for optimizing the referral mechanism and resource allocation within TMTS.
  • YU Hai-run, CHEN Shuo-shuo, LIAO Bo-kai, DONG Wei, XIANG Teng-fei
    Journal of Guangzhou University(Natural Science Edition). 2025, 24(2): 24-35.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    In the contemporary emphasis on maintaining social stability and industrial safety, the issue of low-temperature icing, induced by environmental factors affecting transportation, large-scale machinery, and power transmission lines, stands as an urgent challenge requiring immediate attention. Over the past few years, the rapid development of traditional Superhydrophobic Surface(SHBS) anti-icing coatings has been notable; however, these coatings have also revealed significant limitations, particularly their tendency to lose hydrophobic and anti-icing properties under extreme conditions. In contrast, Superhydrophobic(SH) coatings with photothermal effects have demonstrated sustained effectiveness in harsh environments, offering a promising avenue for further research. This paper begins by elucidating the mechanisms of surface icing, detailing the process by which liquid droplets condense on substrate surfaces. It then reviews various photothermal materials and traditional methods for preparing SHBS. Subsequently, the paper illustrates several composite preparation techniques for SHBS with photothermal effects through specific examples. Finally, after a concise explanation of the photothermal SH anti-icing mechanism, the paper highlights the current limitations of photothermal SH anti-icing surfaces and outlines potential directions for future research.
  • ZHANG Shao-qi, XIA Hai-ming, LING Ling, XIE Yu-hui
    Journal of Guangzhou University(Natural Science Edition). 2025, 24(2): 36-50.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Solar energy has great potential as a clean energy source, but its volatility and instability limit its wide application. Phase change materials (PCMs), as efficient thermal energy storage media with good thermal management properties, can facilitate the utilization of solar energy. Sodium dihydrogen phosphate dodecahydrate (Na2HPO4·12H2O) is an inorganic phase change material that is inexpensive and readily available, with good thermal conductivity and a high latent heat of phase change, but its widespread use introduces a high concentration of corrosive ions, leading to severe corrosion of the metal container. In order to better realise the application of Na2HPO4·12H2O, it is particularly important to study its corrosion mechanism on metal containers and explore effective corrosion inhibition methods. In this study, we investigated the synergistic inhibition effect of benzotriazole (BTA) and thiourea (TU) composite corrosion inhibitor on the corrosion of Q235 carbon steel in Na2HPO4·12H2O molten liquid. The protective mechanism of BTA and TU composite corrosion inhibitors on metal surfaces was investigated by electrochemical techniques including open circuit potentials (OCP), electrochemical impedance spectroscopy (EIS) and polarisation curves with surface characterisation methods such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The results demonstrated that the combined effect of BTA and TU markedly enhanced the corrosion inhibition efficacy. In the 24-hour immersion experiment, the composite corrosion inhibitor system exhibited the highest corrosion inhibition efficacy (98.26%), a figure that was considerably higher than the inhibition efficacy of a single corrosion inhibitor. EIS tests have shown that the corrosion inhibitors BTA and TU are effective in reducing metal corrosion by forming a dense protective film on the metal surface. The BTA300TU100 composite corrosion inhibitor has the best protective effect on the metal surface with high corrosion inhibition efficiency and thicker oxide film. For the application of inorganic phase change materials Na2HPO4·12H2O in solar thermal energy storage, this study provides an effective corrosion inhibition strategy.
  • XI Xiao-yu, ZHANG Mei-ling
    Journal of Guangzhou University(Natural Science Edition). 2025, 24(2): 51-56.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    This paper focuses on the long wavelength limit for the Euler-Poisson system arising in plasma including three species in a three dimensional case. The goal of this study is to deduce rigorously the modified Korteweg-de Vries-ZK(mKdV-ZK) equation, under the Gardner-Morikawa transform ε1/2(x1-Vt)→x11/2x2→x21/2x3→x33/2t→t, asε→0. By employing delicate energy method, we give uniform in ε estimate for the error between the mKdV-ZKequation and the Euler-Poisson system.
  • CHEN Jin-mei, DENG Heng, WANG Guang-wu
    Journal of Guangzhou University(Natural Science Edition). 2025, 24(2): 57-64.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    This investigation delves into the blow-up criteria for strong solutions of the Landau-Lifshitz-Gilbert (LLG) equation, with particular emphasis on when these solutions cease to exist. We construct a comprehensive model and derive multiple blow-up criteria, encompassing Serrin-type, Besov-type, BMO-type, and Beale-Kato-Majda (BKM) type within two- and three-dimensional spaces.
  • LIU Guang, WU Zi-rui, HUANG Si-jie
    Journal of Guangzhou University(Natural Science Edition). 2025, 24(2): 65-73.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    It is critical to predict stock price fluctuations accurately in financial investment. Stock price fluctuations are influenced by multiple factors and have nonlinear characteristics, making traditional linear prediction methods often ineffective. We first selected 5 representative stock indices and 5 large-cap stocks of A-shares as samples, used their daily closing price data from 2020 to 2023, to map their price time series to a high-dimensional space by using the phase space reconstruction (PSR) technique, and reveal their chaotic characteristics. Then, based on the deep learning method Gated Recurrent Unit (GRU), we developed a PSR-GRU prediction method to generate stock price prediction results. Finally, we compared the predicted results with those obtained from classical prediction models. We found that stock price fluctuations have chaotic characteristics, and the PSR-GRU exhibits superior performance in stock price prediction.
  • XIAO Heng-yi, CHEN Ai-xian
    Journal of Guangzhou University(Natural Science Edition). 2025, 24(2): 74-86.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The survivor average causal effect (SACE) can be used to measure the differential impact of receiving different treatments on subjects who would survive under any treatment condition. It represents an important area of research in causal inference. Since the samples of subjects who would always survive in both the treatment and control groups cannot be directly observed, SACE is typically unidentifiable, allowing only for the estimation of its bounds. In the literature, mainstream methods for deriving sharp bounds on SACE rely on multi-parameter linear programming, generating closed-form solutions by enumerating all vertices of the constraint polyhedron in the dual problem. If monotonicity and stochastic dominance conditions are not satisfied, the enumeration method cannot be used to solve this multi-parameter linear programming problem. This paper addresses the sharp bounds of SACE within the principal stratification framework, considering “truncated by death”, stable unit treatment effect, and ignorability assumptions. The optimization problem is solved based on polynomial equations derived from first-order Karush-Kuhn-Tucker (KKT) conditions. The LaLonde dataset from the National Supported Work Demonstration (NSW) project in the United States was empirically selected to calculate the sharp bounds of the SACE under complete covariates for the “always-survivor”.
  • LIANG Zheng-yang, XIANG Yue, TAN Ping
    Journal of Guangzhou University(Natural Science Edition). 2025, 24(2): 87-97.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    To investigate the vibration mitigation performance of the Variable Friction Pendulum Tuned Mass Damper (VFP-TMD) for high-rise structures, the structure is modeled as an Euler-Bernoulli cantilever beam to accurately characterize its dynamic properties. This study presents the configuration of the VFP-TMD device and experimental validation is conducted through tests on variable friction pendulum bearing. A model of the VFP-TMD system subjected to wind-induced excitation is proposed. The optimal parameters of the VFP-TMD are obtained based on the fixed-point theory, and the optimal parameters corresponding to different VFP-TMD mass ratios are provided and analyzed parametrically. A case study involving a landscape tower is performed to analyze wind-induced vibrations. The research results indicate that the proposed optimal parameters achieve superior vibration reduction effects for this system, yielding a peak damping ratio of 51.31% and an average damping ratio of 54.62%.