12 results on '"Changping Feng"'
Search Results
2. Research on the construction of a human-water harmony model in the Yellow River Basin
- Author
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Yan Shi, Shipeng Yang, Weiwei Chen, Xin Wang, and Changping Feng
- Subjects
coupling coordination model ,evaluation index system ,human-water harmony ,spatial-temporal analysis ,the yellow river basin ,River, lake, and water-supply engineering (General) ,TC401-506 - Abstract
Human-water harmony in the Yellow River Basin has an important influence on promoting ecological protection and high-quality development in the Yellow River Basin. This paper explores the degree of harmony between humans and water in the provinces of the Yellow River Basin. Based on the provincial-level data of nine provinces from 2001 to 2020, a human-water harmonious coupling coordination degree model was constructed, and the spatial and temporal analysis of the coupling coordination characteristics of nine provinces was carried out utilizing ArcGIS software. The results revealed that: (1) From the point of view of human-water harmony, from 2001 to 2020, China's human-water relationship was on the rise, from reluctant coupling coordination to good coupling coordination. (2) Qinghai, Gansu, and Sichuan provinces have the most significant increase in human-water harmony, from on the verge of a dysfunctional decline to quality coupling coordination. (3) From 2001 to 2011, the human system's comprehensive index was inferior to that of the water system's comprehensive index. In 2003, the comprehensive index of human and water systems was the largest. From 2012 to 2020, the human system's comprehensive index was higher than the water system. However, in 2015, the two indices diverged significantly HIGHLIGHTS A human-water harmony model was established to evaluate the human-water relationship in the Yellow River Basin.; The spatial and temporal analysis of human-water harmony in nine provinces in the last 20 years was carried out.; Put forward relevant suggestions according to the evaluation results.;
- Published
- 2023
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3. Nano-clay montmorillonite removes tetracycline in water: Factors and adsorption mechanism in aquatic environments
- Author
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Yan Shi, Xin Wang, Changping Feng, and Shipeng Yang
- Subjects
Separation science ,Applied sciences ,Engineering ,Science - Abstract
Summary: In response to escalating environmental concerns surrounding antibiotic pollution, the utilization of calcium-montmorillonite minerals for tetracycline wastewater treatment is gaining prominence. This study systematically analyzed the physicochemical properties of calcium-montmorillonite through scanning electron microscope, contact angle analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. It explored the adsorption efficacy and mechanisms for tetracycline removal, considering factors like initial pH, adsorption duration, concentration, and co-cations (Na+ and Ca2+). Under optimized conditions, achieving over 90% tetracycline removal with a maximum adsorption capacity of 526 mg/g, the study revealed competitive adsorption sites for coexisting cations. The Langmuir model best described the monolayer adsorption process, while kinetic studies favored the pseudo-first-order model. This research offers comprehensive insights into tetracycline adsorption on calcium-montmorillonite, emphasizing its potential as an efficient, cost-effective adsorbent for pharmaceutical wastewater treatment.
- Published
- 2024
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4. A review of the removal of heavy metal ions in wastewater by modified montmorillonite
- Author
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Yan Shi, Songtao Zhong, Xin Wang, and Changping Feng
- Subjects
adsorption ,heavy metal ions ,modification technology ,montmorillonite ,River, lake, and water-supply engineering (General) ,TC401-506 - Abstract
Heavy metal pollution in water environment has always been a hot issue in environmental pollution research. Among various removal methods of heavy metal pollution, adsorption has attracted attention because of its low cost and low secondary pollution. Montmorillonite is one of an ideal adsorption materials because of its natural pore structure and a high specific surface area. In this review, the modification methods of montmorillonite are introduced. The adsorption effect of different heavy metal ions and the main factors affecting the adsorption are discussed in detail. Meanwhile, the adsorption mechanism is intensively reviewed. The removal of Cr(VI), Cd(II), Pb(II), Cu(II), Cs(I), Co(II), Hg(II), Zn(II), Ni(II), and other nine heavy metal ions by modified montmorillonite was summarized and discussed, and the optimal pH values for different adsorbents were also different, but they were all less than 7, and the removal rates of heavy metal ions by modified montmorillonite under optimal conditions were all greater than 90%. It is concluded that the composite montmorillonite material has a great adsorption potential. Finally, it is proposed that the combination of advanced oxidation and composite montmorillonite material adsorption to remove heavy metal ions is an important direction of adsorption and removal of heavy metal ions in the water environment in the future. HIGHLIGHTS Widely collected the domestic and foreign literature works on the modified adsorption of heavy metals by montmorillonite, and used the methods of analysis and synthesis to identify, classify, merge and study the original literature as a whole.; The promising modification direction of montmorillonite and the key points of in-depth research in the removal of heavy metals were put forward.;
- Published
- 2022
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5. Predictive Modeling of Forest Fires in Yunnan Province: An Integration of ARIMA and Stepwise Regression Analysis
- Author
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Yan Shi, Changping Feng, and Shipeng Yang
- Subjects
ARIMA model ,fire prediction ,stepwise regression model ,time series analysis ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
As global warming progresses, forest fires have become more frequent, leading to the destruction of forest biodiversity and consequently affecting Earth’s ecosystems and human living conditions. The ability to predict the long-term trend of forest fires holds significant value for fire prevention and management. In Yunnan Province, China, a region rich in forest resources, this study utilized temperature, average annual rainfall, relative humidity, and wind speed data from 1991 to 2021. We forecasted forest fires using the stepwise regression and autoregressive integrated moving average (ARIMA) model, incorporating the collected forest fire data. The findings reveal a negative correlation between rainfall and forest fire incidence, whereas wind speed exhibited a positive correlation. The ARIMA model forecasts a cyclical trend in fires from 2022 to 2033, with considerable fluctuations in the number of fires, notably in 2027 and 2033. The projected affected area is anticipated to show a marked increase from 2028 onwards. This research not only provides a novel methodology for forecasting forest fires but also lays a scientific foundation for the development of future fire prevention and mitigation strategies.
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- 2023
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6. Characterizing Forest Fuel Properties and Potential Wildfire Dynamics in Xiuwu, Henan, China
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Yan Shi, Changping Feng, Liwei Zhang, Wen Huang, Xin Wang, Shipeng Yang, Weiwei Chen, and Wenjie Xie
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combustion characteristics of combustibles ,forest combustible materials ,fire behavior ,Physics ,QC1-999 - Abstract
As global climate change and human activities increasingly influence our world, forest fires have become more frequent, inflicting significant damage to ecosystems. This study conducted measurements of combustible materials (moisture content ratio, ignition point, and calorific value) across 14 representative sites. We employed Pearson correlation analysis to ascertain the significant differences in combustible properties and utilized entropy methods to evaluate the fire resistance of materials at these sites. Cluster analysis led to the development of four combustible models. Using BehavePlus software, we simulated their fire behaviors and investigated the effects of wind speed and slope on these behaviors through sensitivity analysis. The results revealed notable differences in the moisture content ratios among different types of combustibles, especially in sites 2, 3, 8, 9, and 13, indicating higher fire risks. It was also found that while humus has a higher ignition point and lower calorific value, making it less prone to ignite, the resultant fires could be highly damaging. The Pearson analysis underscored significant variations in the moisture content ratios among different combustibles, while the differences in ignition points and calorific values were not significant. Sites 5 and 6 demonstrated stronger fire resistance. The simulations indicated that fire-spread speed, fireline intensity, and flame length correlate with, and increase with, wind speed and slope. Sensitivity analysis confirmed the significant influence of these two environmental factors on fire behavior. This study provides critical insights into forest fire behavior, enhancing the capability to predict and manage forest fires. Our findings offer theoretical support for forest fire prediction and a scientific basis for fire management decision-making.
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- 2023
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7. Adsorption of cadmium on activated zeolite, characterization, mechanism in micro-polluted water
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Yan Shi, Songtao Zhong, Xin Wang, and Changping Feng
- Subjects
Control and Optimization ,Applied Mathematics ,Mechanical Engineering ,General Engineering ,Biomedical Engineering ,Biophysics ,Aerospace Engineering ,General Physics and Astronomy ,Ocean Engineering ,Statistical and Nonlinear Physics ,General Medicine ,Computer Science Applications ,Computational Mathematics ,Mathematics (miscellaneous) ,Control and Systems Engineering ,Electrical and Electronic Engineering ,General Economics, Econometrics and Finance ,Analysis ,Mathematical Physics ,Social Sciences (miscellaneous) - Published
- 2023
8. Comparison of Two Types of Modified Zeolites and the Key Factors for Cd(II) Adsorption Processes in Micropolluted Irrigation Water
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Wang, Yan Shi, Weiwei Chen, Shipeng Yang, Changping Feng, and Xin
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activation modification ,chitosan loading ,static and dynamic adsorption ,performance comparison - Abstract
Zeolites were modified by high-temperature roasting and chitosan loading, respectively. As a result, activated zeolite and chitosan-loading natural zeolite were obtained. They were used for the treatment of the micro-polluted irrigation water quality simulated by a low concentration (100 μg/L) of Cd(II) contamination. The static adsorption experiments showed that two types of modified zeolites were cost-effective and had high removal efficiency for low concentrations of Cd(II). The removal rates were 95.8% and 92.06%, respectively. The static adsorption experiments investigated the effects of modified zeolite dosage, pH, initial concentration of the solution, and adsorption time on the removal efficiency of cadmium ions. The dynamic adsorption experiments discussed the influence of factors such as dynamic adsorption medium type, influent filtration rate, and adsorbent amount on adsorption efficiency in the adsorption column. The dynamic adsorption experiments adopted intermittent operation to simulate the characteristics of micro-polluted irrigation water. The optimal operating conditions were determined as follows: single activated zeolite filter column or mixed medium (activated zeolite: chitosan loading natural zeolite = 4:1), filtration rate of 6 m/h, filter column height of 500 mm, adsorbent dosage of 30 g. The removal rate was more than 99.5%. The adsorption experiments were represented by Langmuir and Freundlich isotherm models. The adsorption results indicated that the adsorption of modified zeolite showed a better correlation with the Langmuir isotherm model than the Freundlich isotherm model. The adsorption process was described by pseudo-first-order and pseudo-second-order kinetic models, with the pseudo-second-order kinetic model being the predominant mechanism. The average concentration of Cd(II) in the effluent after filtration was 0.41 μg/L, which was far lower than the 0.01 mg/L stipulated in the standard for irrigation water quality (GB5084-2021), and met the requirements of the irrigation water quality standard. Activated zeolite and chitosan-loaded natural zeolite are good adsorbent materials that have broad application prospects in the treatment of micro-polluted irrigation water containing low concentrations of Cd(II).
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- 2023
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9. A predictive model for the relationship between processing conditions and properties of thermoplastic vulcanizates (TPVs) via machine learning
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Xinhu Xu, Lifeng Ma, Hui Guo, Changping Feng, YanSong Wang, and Zhian Mao
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General Engineering ,Ceramics and Composites - Published
- 2023
10. Removal of toluidine blue from water using 1:1 layered clay minerals
- Author
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Yan Shi, Jessica Baker, Changping Feng, Xisen Wang, and Zhaohui Li
- Subjects
Mechanics of Materials ,General Chemical Engineering - Published
- 2022
11. Facile method to fabricate highly thermally conductive UHMWPE/BN composites with the segregated structure for thermal management
- Author
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Hui Lu, Xiao Wang, Changping Feng, Haiying Ni, and Jun Chen
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chemistry.chemical_classification ,Materials science ,Fabrication ,Polymers and Plastics ,General Chemical Engineering ,Hardware_PERFORMANCEANDRELIABILITY ,02 engineering and technology ,Thermal management of electronic devices and systems ,Polymer ,021001 nanoscience & nanotechnology ,Hot pressing ,Conductive composites ,Thermal conductivity ,020401 chemical engineering ,chemistry ,Thermal ,Hardware_INTEGRATEDCIRCUITS ,Materials Chemistry ,Ceramics and Composites ,0204 chemical engineering ,Composite material ,0210 nano-technology ,Electrical conductor - Abstract
Owing to the thermal management of polymer-based thermal conductive composites provide great performance in various applications, widespread attention has been focused on the design and fabrication of thermally conductive materials. In the work, ultrahigh molecular weight polyethylene (UHMWPE) / boron nitride (BN) composites with segregated structures were fabricated by a facile heat-treatment powder mixing method. SEM and optical images revealed that BN flakes can be tightly overlapped on the surface of UHMWPE particles by heat-treatment in the mixing process and the thermally conductive network was more continuous and homogeneous, leading to the greatly improved thermal conductivity. Laser flash thermal analyzer (LFA) demonstrated that an optimised in-plane thermal conductivity of UHMWPE/BN composites fabricated by the heat-treatment powder mixing method can reach to 9.99 W m−1 K−1 by adjusting the BN loading to 21.6 vol %. In summary, the UHMWPE/BN composite with high thermal conductivity provides excellent heat dissipation ability in the in-plane direction, which is very important for thermally conductive materials.
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- 2020
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12. Advances in second-generation high-temperature superconducting tapes and their applications in high-field magnets
- Author
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Kai Wang, Hao Dong, Daxing Huang, Hongjing Shang, Bowei Xie, Qi Zou, Lin Zhang, Changping Feng, Hongwei Gu, and Fazhu Ding
- Abstract
Second-generation high-temperature superconducting (2G-HTS) tapes based on REBa2Cu3O7-x (REBCO, RE: rare earth) materials enable the energy-efficient and high-power-density delivery of electricity, thereby promoting the development of clean energy generation, conversion, transmission, and storage. To overcome the weak grain-boundary connection and poor mechanical properties of these superconductors, a thin-film technology for epitaxy and biaxial textures based on flexible substrates has been developed. In recent years, high-quality 2G-HTS tapes have been produced at the kilometer scale and used in superconducting demonstration projects. This review first summarizes the development of HTS materials and briefly expounds the properties of REBCO superconducting materials. Subsequently, the structural characteristics, preparation methods, and current research progress of 2G-HTS tapes are given. In addition, the applications of REBCO tapes in constructing high-field magnets are also briefly reviewed.
- Published
- 2022
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