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    Journal of East China Normal University(Natural Science)    2023, 2023 (6): 0-x.  
    Abstract91)   HTML13)    PDF (365KB)(796)      
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    Comprehensive review on green synthesis of bio-based 2,5-furandicarboxylic acid
    Lei ZHAO, Zelin LI, Bolong LI, Shuchang BIAN, Jianhua WANG, Hailan ZHANG, Chen ZHAO
    Journal of East China Normal University(Natural Science)    2023, 2023 (1): 160-169.   DOI: 10.3969/j.issn.1000-5641.2023.01.016
    Abstract1420)   HTML77)    PDF (1090KB)(860)      

    Bio-based 2,5-furandicarboxylic acid (FDCA) is expected to partially replace petroleum-based terephthalic acid (PTA) for the synthesis of high-performance polymer materials. This review article summarizes the latest achievements on the various synthesis routes of FDCA from 5-hydroxymethylfurfural (HMF), furoic acid, furan, diglycolic acid, hexaric acid, 2,5-dimethylfuran, and 2-methylfuran. In particular, the direct oxidation, heterogeneous thermal catalytic oxidation, photoelectric catalytic oxidation of HMF and furoic acid carboxylation, disproportionation, carbonylation, and other routes to synthesize FDCA are reviewed in detail. Based on the comparative analysis of the advantages and disadvantages of each route, the HMF route and the furoic acid route are considered the most promising candidates for the large-scale production of FDCA. Further exploration and future research should be carried out to improve the catalytic production and separation efficiency of FDCA, simplify the reaction process, and reduce production wastes.

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    Study on the mechanism of methylene blue degradation by TiO2 photocatalyst
    ZHANG Dan, XU Bin, ZHU Pei-juan, LIAN Zheng-hao, ZHAO Ya-ping
    Journal of East China Normal University(Natural Sc    2013, 2013 (5): 35-42.  
    Abstract3505)      PDF (2193KB)(4003)      
    In order to carry out the study, the experiments of photodegradation of methylene blue under different conditions were conducted, using different kinds of free radical scavengers, such as (CH3)3OH, H2O2, KI, NaN3 and C6H4O2. The effects of these free radical scavengers were observed. The concentration of H2O2 generated during the photodegradation of methylene blue by TiO2 was also reported. And the results of these experiments indicated that the main active oxygen substances in the reaction are ·OH, O·-2 and 1O2.
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    State of marine microplastic pollution research and the limitations
    LI Dao-ji, Zhu Li-xin, CHANG Si-yuan, ZHANG Feng, WANG Lu
    Journal of East China Normal University(Natural Sc    2019, 2019 (3): 174-185.   DOI: 10.3969/j.issn.1000-5641.2019.03.019
    Abstract602)   HTML40)    PDF (1724KB)(760)      
    Microplastics (less than 5 mm in diameter) are ubiquitously distributed throughout the world's oceans. Marine microplastic pollution has become a global research hotspot and a new frontier in ecological and environmental sciences. The issue has increasingly attracted the attention of scientists, government agencies, and NGOs worldwide. Although the problem of marine plastic pollution was first discovered in the 1970s, it didn't gain attention in the international arena until recent years. Since then, microplastic research has progressed rapidly both globally and in China. However, there are still many problems with the research and response to marine microplastics, requiring further clarification and solutions. This paper first briefly reviews the chronological development of marine microplastic research as well as the role and significance of key events. Thereafter, the paper discusses the state of marine microplastic pollution research and the mitigation efforts in China and abroad, highlighting the current limitations in the research and response to marine plastic and microplastic pollution.
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    Recognition of classroom learning behaviors based on the fusion of human pose estimation and object detection
    Zejie WANG, Chaomin SHEN, Chun ZHAO, Xinmei LIU, Jie CHEN
    Journal of East China Normal University(Natural Science)    2022, 2022 (2): 55-66.   DOI: 10.3969/j.issn.1000-5641.2022.02.007
    Abstract1203)   HTML111)    PDF (1026KB)(1376)      

    As a result of ongoing advances in artificial intelligence technology, the potential for learning analysis in teaching evaluation and educational data mining is gradually being recognized. In classrooms, artificial intelligence technology can help to enable automated student behavior analysis, so that teachers can effectively and intuitively grasp students’ learning behavior engagement; the technology, moreover, can provide data to support subsequent improvements in learning design and implementation of teaching interventions. The main scope of the research is as follows: Construct a classroom student behavior dataset that provides a basis for subsequent research; Propose a behavior detection method and a set of feasible, high-precision behavior recognition models. Based on the global features of the human posture extracted from the Openpose algorithm and the local features of the interactive objects extracted by the YOLO v3 algorithm, student behavior can be identified and analyzed to help improve recognition accuracy; Improve the model structure, compress and optimize the model, and reduce the consumption of computing power and time. Four behaviors closely related to the state of learning engagement: listening, turning sideways, bowing, and raising hands are recognized. The accuracy of the detection and recognition method on the verification set achieves 95.45%. The recognition speed and accuracy of common behaviors, such as playing with mobile phones and writing, are greatly improved compared to the original model.

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    Joint extraction of entities and relations for domain knowledge graph
    Rui FU, Jianyu LI, Jiahui WANG, Kun YUE, Kuang HU
    Journal of East China Normal University(Natural Science)    2021, 2021 (5): 24-36.   DOI: 10.3969/j.issn.1000-5641.2021.05.003
    Abstract717)   HTML70)    PDF (842KB)(579)      

    Extraction of entities and relationships from text data is used to construct and update domain knowledge graphs. In this paper, we propose a method to jointly extract entities and relations by incorporating the concept of active learning; the proposed method addresses problems related to the overlap of vertical domain data and the lack of labeled samples in financial technology domain text data using the traditional approach. First, we select informative samples incrementally as training data sets. Next, we transform the exercise of joint extraction of entities and relations into a sequence labeling problem by labelling the main entities. Finally, we fulfill the joint extraction using the improved BERT-BiGRU-CRF model for construction of a knowledge graph, and thus facilitate financial analysis, investment, and transaction operations based on domain knowledge, thereby reducing investment risks. Experimental results with finance text data shows the effectiveness of our proposed method and verifies that the method can be successfully used to construct financial knowledge graphs.

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    Study of electronic structures and the micro-solvation effect of SO3 and HSO3 in atmospheric aerosols
    Jianan CHEN, Zhipeng LI, Yanrong JIANG, Zhubin HU, Haitao SUN, Zhenrong SUN
    Journal of East China Normal University(Natural Science)    2022, 2022 (1): 31-42.   DOI: 10.3969/j.issn.1000-5641.2022.01.005
    Abstract352)   HTML49)    PDF (942KB)(696)      

    In this study, we used negative ion photoelectron spectroscopy (NIPES) combined with quantum chemical calculation to explore the electronic structures, micro-solvation effect, and stabilization mechanism of two compounds, SO3 and HSO3, that are readily abundant in the atmosphere. Vertical detachment energies of (3.31 ± 0.02) and (3.91 ± 0.02) eV and adiabatic detachment energies of (3.02 ± 0.05) and (3.56 ± 0.05) eV were measured for SO3 and HSO3, respectively. These results are reproduceable when using a nuclear ensemble approach and Dyson orbitals in the calculation. The typical density of states method, however, cannot demonstrate the nuclear vibration effect, ionization probability, and orbital relaxation effect during the ionization process. We studied the micro-solvation effect of HSO3·(H2O)n (n = 0 ~ 5) and found that system stability was enhanced by an increase in the surrounding water molecules, whereby electrostatic interaction played a dominant role and the induction effect made an increasingly important contribution. We believe this work will help improve the modeling of atmospheric sulfate aerosols and provide a scientific basis for the effective control of haze formation.

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    3D obstacle-avoidance for a unmanned aerial vehicle based on the improved artificial potential field method
    Lanfeng ZHOU, Mingyue KONG
    Journal of East China Normal University(Natural Science)    2022, 2022 (6): 54-67.   DOI: 10.3969/j.issn.1000-5641.2022.06.007
    Abstract542)   HTML17)    PDF (2858KB)(288)      

    This paper aims to address the challenge of seeking an optimal safe path for a UAV (unmanned aerial vehicle) from an initial position to a target position, while avoiding all obstacles in a three-dimensional environment. An improved APF (artificial potential field) method combined with the regular hexagon guidance method is proposed to solve unreachable and local minimum problems near obstacles as observed with traditional artificial potential field methods. First, we add a distance correction factor to the repulsive potential field function to solve problems associated with unreachable targets. Then, a regular hexagon-guided method is proposed to improve the local minimum problem. This method can judge the environment when the UAV is trapped in a local minimum point or trap area and select the appropriate planning method to guide the UAV to escape from the local minimum area. Then, 3D modeling and simulation were carried out via Matlab, taking into account a variety of scenes involving complex obstacles. The results show that this method has good feasibility and effectiveness in real-time path planning of UAVs. Lastly, we demonstrate the performance of the proposed method in a real environment, and the experimental results show that the proposed method can effectively avoid obstacles and find the optimal path.

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    Catalytic asymmetric synthesis of chiral heterocyclic compounds with CO2 as the C1 synthon
    Zhipeng ZHAO, Ying SUN, Xiaotong GAO, Feng ZHOU
    Journal of East China Normal University(Natural Science)    2023, 2023 (1): 31-40.   DOI: 10.3969/j.issn.1000-5641.2023.01.004
    Abstract299)   HTML10)    PDF (1463KB)(364)      

    As the main component of greenhouse gases, CO2 represents an inexpensive and readily available renewable C1 synthon. In the past few decades, great efforts have been made toward the development of chemical processes that use CO2 as a promising fossil fuel alternative for C1 feedstocks for the production of industrially attractive chemicals. This could provide access to materials of commercial interest from an abundant, nontoxic, renewable, and low-cost carbon source, thus offering interesting opportunities for the chemical industry, organic synthesis, and so on. Considering the importance of chiral heterocycles in organic synthesis and drug development, the development of highly stereoselective and efficient catalytic asymmetric reactions using CO2 as a C1 synthon for these chiral heterocycles has received considerable attention. Successful examples for chiral lactones, carbonates, and carbamates have already been demonstrated. In this paper, we summarize the recent advances in this field.

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    Review of zeolite-confined subnanometric cluster catalysts
    Yue MA, Hao XU, Yueming LIU, Kun ZHANG, Peng WU, Mingyuan HE
    Journal of East China Normal University(Natural Science)    2023, 2023 (1): 82-94.   DOI: 10.3969/j.issn.1000-5641.2022.00.009
    Abstract547)   HTML26)    PDF (5085KB)(346)      

    The design of efficient and stable supported metal catalysts to prevent metal species from sintering into large nanoparticles under harsh preparation and reaction conditions is key for various important processes, including the conversion of C1 resources and dehydrogenation of low carbon alkanes to C2 and C3 olefins. Zeolites with uniform subnano micropores and various three-dimensional crystalline structures have been proven as ideal supports for preparing highly efficient and stable metal catalysts via encapsulating subnanometric metal clusters within their pores, cages, and channels. Interactions between metal clusters and the zeolite skeleton can regulate their geometric and electronic structure. The development of zeolite-confined subnanometric cluster catalysts aims to take advantage of this joint confinement effect and induce synergy between guest metal species and active sites in host zeolite frameworks. This can further improve the catalytic activity of resultant composite catalysts, for applications in multiple catalytic reaction processes . In this review, typical preparation methods of zeolite-confined subnanometric clusters and their catalytic applications in selective hydrogenation of CO2 and alkynes, hydrogen generation by formic acid decomposition and ammonia borane hydrolysis, and propane dehydrogenation to propene are discussed.

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    The impacts of climate change on the coastal zone of Mauritius
    Yuvna Devi PERIANEN, Xi XIAO
    Journal of East China Normal University(Natural Science)    2020, 2020 (S1): 104-108.   DOI: 10.3969/j.issn.1000-5641.202092213
    Online available: 22 January 2021

    Abstract510)   HTML29)    PDF (390KB)(336)      
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    Preparation and stability study of lyophilized lentiviral vector
    Hongwei SHEN, Minghao LI, Nan XU, Jiaqi SHAO, Jing WANG, Lei YU
    Journal of East China Normal University(Natural Science)    2021, 2021 (3): 114-127.   DOI: 10.3969/j.issn.1000-5641.2021.03.012
    Abstract785)   HTML50)    PDF (1003KB)(428)      

    In this paper, we studied a new preparation technique for lyophilized lentiviral vectors. We determined the optimal formulation for a freeze-drying protective agent by screening and optimizing potential candidates. The candidates were evaluated on the basis of physical and chemical properties of the freeze-drying process, including appearance, excipient, color, and solubility. The optimal formulation was determined to be trehalose 0.30 g/mL, L-histidine 0.31 mg/mL, L- alanine 0.178 mg/mL, CaCl2 0.020 mg/mL, and MgSO4 0.015 mg/mL. With this technique, the prepared lyophilized lentiviral vector had good appearance, low residual water content, intact structure, and good re-dispersibility. The biological titer of the lentiviral vector reached 9.37 × 107 IU/mL, and the recovery rate of the titer was 50.15%. We also conducted research on potential influencing factors, including a high temperature accelerated experiment and repeated freeze-thaw stability experiments. These experiments showed that the lyophilizing technology can be used for the preparation of lentiviral vector solids and can be effectively used to improve the storage of lentiviral vectors under different temperature conditions, exposure to repeated freeze-thaw cycles, and tolerance to adverse environments (e.g., high temperatures).

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    Quantum nondemolition measuremen generated spin-squeezed Bose-Einstein condensate confined in a double-well trap
    Yangxu JI, Ebubechukwu O. ILO-OKEKE, Tim BYRNES
    Journal of East China Normal University(Natural Science)    2022, 2022 (4): 154-162.   DOI: 10.3969/j.issn.1000-5641.2022.04.016
    Abstract212)   HTML23)    PDF (1077KB)(163)      

    This paper studies the use of quantum nondemolition (QND) measurement to produce a spin squeezed atomic Bose-Einstein condensate (BEC) in a double-well trap. The spin squeezed atomic Bose-Einstein condensate is performed by putting the BECs of a double well in the two arms of a Mach Zehnder interferometer and performing a QND measurement. The dynamics of the light-atom system are solved using an exact wave-function approach, in contrast to previous approaches where approximations were made using techniques like the Holstein-Primakoff approximation. The backaction of the measurement on atoms is minimized by monitoring the condensate at zero detection current and the identical coherent beams. At the weak atom-light interaction limit, we find that the average spin direction is relatively unaffected by observing the conditional probability distribution and the Q function distribution. The spin variance is squeezed along the axis of optical coupling.

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    Effects of nutrient management on nutrient utilization of N,P and nitrate accumulation in lettuce
    NIAN Yao-ping, XIA Ti-yuan, HE Ming-zhu,ZHANG Jun-guo, DA Liang-jun
    Journal of East China Normal University(Natural Sc    2011, 2011 (6): 47-56.  
    Abstract2981)      PDF (810KB)(2388)      
    By method of the field plot trial, the experiment was carried out in Dianchi Lake basin to study the influence of different nitrogen and phosphorus fertilizing on lettuce (Lactuca sativa var. ramosa) production, nitrate content and nutrient utilization of N, P. 9 treatments were denoted by T1-T9, respectively. The results showed that: ① The lettuce production of T3(N90P126K180) was higher than other treatments, reaching 28 968.75 kg/ha; except for treatment of T4(N180P126K180)、T5(N270P126K180) and T8(N180P189K180), the contamination levels of nitrate content of the others came out to be Lv.4; after comprehensive consideration on nutrient utilization of N, P, the nutrient utilization of Lettuce showed to be higher after treatments of T4(N180P126K180) and T9(N90P63K180) with 17.42%,2.10% and 20.14%,2.05% respectively. ② Under the same amount of potash fertilizer and the treatment of appropriate nitrogen and phosphorus fertilizers match fertilizing, the corresponding lettuce production, nitrate content and N, P fertilizer nutrient utilization were superior to treatments of partial fertilization or high fertilization. Therefore, control of nitrogen and phosphorus fertilizing, reasonable optimization of ratios of nitrogen and phosphorus will improve the nutrient utilization and vegetables quality, which is of great importance for source controlling the agricultural non-point pollution.
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    Distribution and characteristics of the mossy dwarf forests in China
    XU Jie;WANG Xi-hua
    Journal of East China Normal University(Natural Sc    2010, 2010 (4): 44-57.  
    Abstract2801)      PDF (1371KB)(2470)      
    Based on plots investigation and literatures of the mossy dwarf forests, this study tried to determine their distribution in China, analyzed the species composition and floristic geographic elements of this kind of forests, and calculated the similarity among communities. The results showed that these communities scattered in a large areas of southern provinces as “islands” in China, with the northern boundary located in the Funiu Mountain in Henan Province. The distribution sites appeared to vary with threestep topography in China and altitude in every specific mountain. The floristic composition which included 16 species of Pteridophytes and 251 species of Spermatophytes was not complicated. The floristic arealtype elements were affected by tropical and subtropical flora,and also influenced by temperate. From east to west, significant differences was found to exist in mossy dwarf forest communities: in the east the similarity was higher while the richness 〖JP2〗was lower in the eastern and northern part. In view of the unique habitats and particular distribution of these communities, more attention should be paid to the protection of this type of ecosystem and further studies are needed.
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    Evaluation of eutrophication by satellite remote sensing based on machine learning: A case study of Huancheng River in Hefei
    Yong ZHANG, Hui WANG, Chuanhua ZHU, Hao ZHOU, Yu ZHAN, Can LI, Yifan XIAO, Lili YANG, Jiaqi LIU
    Journal of East China Normal University(Natural Science)    2024, 2024 (1): 1-8, 112.   DOI: 10.3969/j.issn.1000-5641.2024.01.001
    Abstract52)   HTML82)    PDF (1874KB)(38)      

    Taking Huancheng River in Hefei City as the study site, machine learning models such as linear regression, random forest, support vector regression, and lasso regression were utilized to establish the relationship between Landsat8 satellite data and water quality parameters, model the reflectance and water quality parameters of remote sensing image values, and compare the performance of four different models. Results showed that the random forest model performed best, and the accuracy of the inversion models for total nitrogen (TN), total phosphorus (TP), and ammonia nitrogen (NH3-N) was above 0.7. The concentration distribution map of water quality parameters showed that the pollution of TN and TP was the most significant in the northeast section of Huancheng River, while NH3-N was most present in the southwest section. The water eutrophication distribution map shows that the water body in the eastern section of the Huancheng River showed a moderate nutrition state.

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    Natural gas hydrates potential in Pakistan: A possible solution to meet future energy demands
    Ubedullah ANSARI, Yuanfang CHENG, Xiaohui ZHOU, Jiping DING, Qingchao LI
    Journal of East China Normal University(Natural Science)    2020, 2020 (S1): 84-88.   DOI: 10.3969/j.issn.1000-5641.202092206
    Abstract372)   HTML18)    PDF (418KB)(235)      
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    Structure-conductive property relationship of polypyrrole
    YU Bo, XU Xue-cheng
    Journal of East China Normal University(Natural Sc    2014, 2014 (4): 77-87.  
    Abstract2273)      PDF (1700KB)(4065)      
    Polypyrrole was synthesized by oxidative chemical polymerization. Samples presenting different conductivities were obtained by adjusting the preparing temperature. The polypyrrole samples have been investigated by means of four probe method, Solid state 13C NMR spectrum, XRD, FTIR spectroscopy, Raman spectrum and XPS, respectively. The experimental result suggested the fact that the conductivity of polypyrrole samples gradually decreases as the preparation temperature increases. The analysis indicates it is because the changing of internal structure follows the varying of external preparation conditions. The commonly structure of polypyrrole is a linear chain of monomers bonded by α-α carbons at a low preparation temperature. Through such a structure polypyrrole can form both a relatively planar configuration and a relatively planar conformation. This sort of structure provides the sample with a preferable regularity, a longer conjugated chain length and a higher conductivity. However, the ratio of α-α linkage drops as the preparation temperature increases, by which the structure of molecular is damaged, the degree of order declines. The carrier mobility of polypyrrole, as well as the conductive property, became lower.
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    XUE Peng
    Journal of East China Normal University(Natural Sc    2015, 2015 (S1): 180-184.   DOI: 10.3969/j.issn.1000-5641.2015.z1.029
    Abstract837)      PDF (573KB)(2112)      
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    Numerical simulation of transport and diffusion of thermal discharge water from the power plants in the Changjiang estuary
    WU Yu-fan, ZHU Jian-rong
    Journal of East China Normal University(Natural Sc    2017, 2017 (2): 126-137,147.   DOI: 10.3969/j.issn.1000-5641.2017.02.016
    Abstract430)   HTML13)    PDF (1859KB)(1090)      

    The three dimensional numerical model of thermal discharge water in the Changjiang estuary was established to simulate the transport and diffusion of thermal discharge water from the Huaneng Shidongkou first power plant under second-phase rebuild project and the whole power plants in the estuary in summertime, and analyze their impacts on the sensitive targets. The thermal discharge water transports and diffusions downstream along the south coast of the South Branch affected by the runoff and mixing. In the case of only considered the project, there appeared area of temperature rise of greater than 2.0℃ near the drain outlet, while the impact is weak and the temperature rise is only 0.04℃ in the water intake. The area of whole tide-averaged surface temperature rise of 3.0, 2.0 and 1.0℃ is 0.12, 0.60 and 1.42 km2, respectively. The tidal and week averaged temperature rise envelope of 1℃ does not enter the water source protection area of Chenhang reservoir. In the case of considered the whole power plants in the estuary, the area of temperature rise of greater than 1.0℃ is wider, mainly distributes along the south coast of the South Branch in 50 km range from Taicang power plants to the downstream coast of Waigaoqiao power plants. The temperature rise is significant and appears wider area of greater than 4℃ near the Huaneng power plants and downstream water. The areas of whole tide-averaged temperature rise of 3.0, 2.0, 1.0℃ reach 2.34, 4.16, 13.52 km2, respectively. The temperature rise is higher and stratification near the coast, and decreases off the coast along the sections cross the water intake and drain outlet of the project. The isotherm of temperature rise of 1℃ invades the water source protection area of Chenhang reservoir. The area of temperature rise of 1℃ averaged during spring, middle, neap and week reaches 1.9, 1.82, 1.75 and 1.83 km2 in the secondary water source reserve of Chenhang reservoir. There is no impact of thermal discharge water from the whole power plants in the Chnagjiang Estuary on the water source protection area of Qingcaosha and Dongfeng xisha reservoir, Jiuduansha wetland nature reserve and Chongming Estern shoal birds nature reserve.

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