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    The Chinese experience at the International Mathematical Olympiad
    Bin XIONG, Peijie JIANG
    Journal of East China Normal University(Natural Science)    2021, 2021 (6): 1-14.   DOI: 10.3969/j.issn.1000-5641.2021.06.001
    Abstract251)   HTML713)    PDF (1371KB)(203)      

    The International Mathematical Olympiad (IMO) is one of the most important and influential global youth intellectual competitions. However, there is little research on how to effectively organize the competition at the national level to help cultivate talent in mathematics, science, and technology. The Mathematical Olympiad originated from a competition to solve mathematical problems. Many outstanding mathematicians and scientists have been prior winners of the IMO and have reaped benefits subsequently to some extent. The Mathematical Olympiad helps to select and train gifted students in mathematics. China’s outstanding historical achievements in the IMO have attracted the attention of the world. Many of China’s students, who exhibited exceptional performance at the IMO, later became outstanding mathematicians, scientists, and technologists. These achievements need to be publicized, and the Chinese experience at the Mathematical Olympiad needs to be summarized and promoted. This article summarizes the history of the IMO and reviews the practices of the IMO in China based on the literature. China uses a number of strategies to ensure outstanding results in the IMO, including: the selection of contestants from existing domestic programs (National High School Mathematics Joint Competition, Chinese Mathematical Olympiad, and National Training Team); a multi-level educational system based on school training; and the accumulation and publication of relevant learning materials. The outbreak of the novel coronavirus has affected the normal proceedings of the IMO, but China has implemented effective countermeasures. There are still some misunderstandings about the Mathematical Olympiad in China. By introducing prior contestants, who have participated in the IMO and made outstanding contributions, China can help the public better appreciate the Mathematical Olympiad. At the same time, the Chinese experience at the IMO is an important reference for other countries in organizing competition training and selecting and nurturing gifted students in mathematics.

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    Research progress of microplastics and attached organisms in marine environment
    Daoji LI, Xuri DONG
    Journal of East China Normal University(Natural Science)    2022, 2022 (3): 1-7.   DOI: 10.3969/j.issn.1000-5641.2022.03.001
    Abstract248)   HTML876)    PDF (475KB)(163)      

    In recent years, white pollution caused by waste plastics has attracted widespread attention. Microplastics, which are smaller than 5 mm, are widely distributed in the marine environment. The organisms attached to microplastic surfaces include potential pathogenic bacteria that are harmful to marine life and even human health, as well as plastic-degrading bacteria that can reduce their pollution. Microplastics are difficult to degrade, so they can exist in the aquatic environment for a long time, and the microorganisms attached to their surface can also live stably. In addition, microplastics may pass through the food chain to organisms at higher nutritional levels, and may be eaten by fish and affect fish growth. This paper reviews the distribution of microplastics in the ocean and the potential effects of harmful substances contained or attached to the microplastic surface on organisms. The ecological effects of pathogenic microorganisms attached to the surface of microplastics and plastic decomposition microorganisms, as well as the potential of microplastic transmission to high nutritional levels through the food chain were discussed. The ecological risk of microplastic distribution and surface-attached organisms was analyzed. Furtherly, it is still necessary to understand the impact of plastic waste and microplastics on the marine ecosystem, so as to fully understand the ecological effects of marine microplastics and their attachments, and provide a scientific basis for marine plastic pollution control.

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    Effect of silicon/carbon composite structure on its electrochemical performance as a lithium-ion battery anode
    Xiaohua TIAN, Chenlu YU, Han ZHENG, Zhuo SUN, Zhejuan ZHANG, Xianqing PIAO
    Journal of East China Normal University(Natural Science)    2022, 2022 (1): 52-61.   DOI: 10.3969/j.issn.1000-5641.2022.01.007
    Abstract240)   HTML48)    PDF (1541KB)(139)      

    Porous silicon/hard carbon composite (Si@CTS) was successfully fabricated using liquidphase encapsulation and a low-temperature pyrolysis process, in which silicon particles from cutting waste in the manufacturing of crystalline silicon solar cells was used as a raw material and chitosan as carbon source. In this paper, the electrochemical performance of Si@CTS and a mixture of Si@CTS and graphite (Si@CTS/G) as anode materials of a lithium-ion battery was studied. The Si@CTS electrode showed a high discharge specific capacity of 1672.8 mAh/g and a high initial coulombic efficiency of 84.45%. After 100 cycles, the Si@CTS retained a reversible capacity of 626.4 mAh/g. The discharge specific capacity of the Si@CTS/G composite was 698.1 mAh/g; hence, the discharge specific capacity of the Si@CTS/G composite was higher than that of Si@CTS and offered better stability. The findings are critical for mass manufacture and deployment of silicon/carbon anodes with high capacity and stability in lithium-ion batteries.

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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
    Abstract236)   HTML49)    PDF (1026KB)(270)      

    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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    Yolk-shell silicon anode material coated with nitrogen-doped carbon
    Kaijing BAO, Zhaokai ZHANG, Xianqing PIAO, Zhuo SUN
    Journal of East China Normal University(Natural Science)    2022, 2022 (1): 22-30.   DOI: 10.3969/j.issn.1000-5641.2022.01.004
    Abstract220)   HTML206)    PDF (1375KB)(98)      

    Using resorcinol-formaldehyde resin as the carbon source, melamine as the nitrogen source, and NaOH as the etchant, a nitrogen-doped carbon-coated silicon (Si@void@N-C) anode material with a yolk-shell structure was synthesized. The samples were characterized and tested by XRD, SEM and X-ray photoelectron spectroscopy, TEM, and electrochemical tests; the results confirmed that a Si@void@NC composite anode material with a yolk-shell structure was successfully synthesized. The material was found to have excellent electrochemical performance. The initial capacity reached 1282.3 mA/g after charging and discharging at a current density of 0.1 A/g. After 100 cycles, its specific capacity was as high as 994.2 mAh/g with a capacity retention of 77.5%, demonstrating good cycle performance. The nitrogen-doped carbon shell of the Si@void@N-C material helps with the electrical conductivity of the composite material. Meanwhile, the yolk-shell structure effectively alleviates the volume effect of silicon; this feature is beneficial to the formation of a stable SEI film and improves the cycle stability of the battery.

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    Optically mediated entanglement between Bose-Einstein condensates
    Shuai GAO, Matthew PREST, Ebubechukwu O. ILO-OKEKE, Manikandan KONDAPPAN, Juan E. ARISTIZABAL-ZULUAGA, Valentin IVANNIKOV, Tim BYRNES
    Journal of East China Normal University(Natural Science)    2022, 2022 (2): 93-105.   DOI: 10.3969/j.issn.1000-5641.2022.02.011
    Abstract207)   HTML44)    PDF (1315KB)(75)      

    This paper explores a method for generating optically mediated entanglement between Bose-Einstein condensates (BECs). Using a quantum nondemolition Hamiltonian with BECs placed in a Mach-Zehnder configuration, it is shown that entangled states can be induced by performing measurement on light. In particular, the effects of the entangled state in the presence of decoherence were analyzed. The behavior of the entangled state was found to be sensitive to the atom-light interaction time. The entangled state is relatively stable when the dimensionless interaction time $ \tau \lesssim \frac{1}{\sqrt{N}} $ and relatively fragile when the time is greater.

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    Bryophyte diversity of a grassland mining area and its relationship with soil physical and chemical properties
    Chao FENG, Yuchen GAN, Xiao HE, Shaogang LEI, Wei CHENG, Jiu HUANG, Jin KOU
    Journal of East China Normal University(Natural Science)    2022, 2022 (1): 76-84.   DOI: 10.3969/j.issn.1000-5641.2022.01.010
    Abstract205)   HTML42)    PDF (797KB)(84)      

    In this study, the Shengli Coal Mine—a representative coal mine in the semi-arid grassland of Inner Mongolia—and the adjacent Beizi Temple, Botanical Garden, and Nanshan Reservoir were selected as the study areas. By studying the correlation between the characteristics of the bryophyte community and the physical and chemical properties of the soil, the influence of soil on the distribution of bryophytes was analyzed during the reclamation process. The results showed that there were 4 families, 6 genera, and 7 species of bryophytes in the Shengli mining area. The total coverage of bryophytes in each habitat could be ranked according to the following order: Beizi Temple > Botanical Garden > south dump of the mining area > Nanshan Reservoir > plantation in the mining area > north dump of the mining area. An analysis of the diversity index, moreover, showed that the Shannon-Wiener index at the south dump was the highest, indicating that the species complexity of the moss community at the south dump was relatively high. An analysis of the correlation between the coverage of the bryophyte community and the physical and chemical properties of the soil showed that the soil pH value, silt content, sand content, and gravel content all had significant effects on the distribution of bryophytes. Multivariate analysis of the bryophyte community structure and soil physical and chemical properties showed that the differences in bryophyte community structure between different study areas was related to the cumulative influence of environmental factors.

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    Infinite dimensional 3-Pre-Lie algebras
    Ruipu BAI, Shan LIU
    Journal of East China Normal University(Natural Science)    2022, 2022 (2): 1-8.   DOI: 10.3969/j.issn.1000-5641.2022.02.001
    Abstract200)   HTML296)    PDF (625KB)(105)      

    Constructing 3-Pre-Lie algebras has always been a difficult problem; until now, there have been very few examples of 3-Pre-Lie algebras. In this paper, we use homogenous Rota-Baxter operators of weight zero on the infinite dimensional 3-Lie algebra $A_{\omega}=\langle L_m | m\in {\mathbb{Z}}\rangle$ to construct 3-Pre-Lie algebras $B_k,~0\leqslant k\leqslant 4$ , and we subsequently discuss the structure. It is shown that $B_2$ and $B_4$ are non-isomorphic simple 3-Pre-Lie algebras, $B_1$ is an indecomposable 3-Pre-Lie algebra with infinitely many one-dimensional ideals, and $B_3$ is an indecomposable 3-Pre-Lie algebra with finitely many ideals.

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    Spatial accessibility of elderly healthcare facilities based on an improved potential model: A case study on Fengxian District in Shanghai
    Tianyan WU, Qingtao XIA, Zhen CHEN
    Journal of East China Normal University(Natural Science)    2022, 2022 (1): 85-96.   DOI: 10.3969/j.issn.1000-5641.2022.01.011
    Abstract195)   HTML43)    PDF (1193KB)(74)      

    Spatial accessibility is an important reference index to determine whether the layout of various types of facilities is reasonable. Scientific evaluation of the spatial accessibility of service facilities is an important basis for judging regional service differences and optimizing the spatial allocation of resources. Using the basic potential model as a basis for our analysis, we introduced a demand-side threshold, designed a three-level service radius based on the scale requirements for elderly care institutions, and implemented regional priority matching principles. Taking Fengxian District of Shanghai as an example, we analyzed the spatial accessibility of elderly care institutions in the region based on the actual driving time between supply and demand points and ArcGIS spatial analysis technology. The results show that the spatial accessibility of nursing homes in Fengxian District is uneven, and the spatial accessibility in some areas of Nanqiao Town, Zhuanghang Town, and Jinhui Town is significantly higher. A trend of gradually decreasing accessibility can be observed from the city center to the periphery. In some towns and villages of the central region, there are dense elderly care institutions and relatively concentrated elderly resources. The improved potential model considers the influence of factors such as the service capacity of elderly care institutions and the needs of the elderly, which can evaluate the spatial accessibility of institutions more effectively. The research results provide a reference point and offer suggestions for scientific planning and decision-making of elderly care institutions.

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    Network anomaly traffic detection based on ensemble feature selection
    Qiwen HUANG, Liying LI, Fuke SHEN, Tongquan WEI
    Journal of East China Normal University(Natural Science)    2021, 2021 (6): 100-111.   DOI: 10.3969/j.issn.1000-5641.2021.06.011
    Abstract194)   HTML65)    PDF (1321KB)(90)      

    With the continuous development of Internet technology, network security is garnering increasing attention. Network anomalous traffic detection can provide an effective guarantee for blocking network attacks. However, to accurately detect anomalous traffic in a network, analyzing large volumes of data is usually required. Analyzing this data not only consumes substantial computational resources and reduces real-time detection capability, but it may also reduce the overall accuracy of detection. To solve these problems, we propose a network anomaly traffic detection method based on ensemble feature selection. Specifically, we use five different feature selection algorithms to design a voting mechanism for selecting feature subsets. Three different machine learning algorithms (Naive Bayesian, Decision Tree, XGBoost) are used to evaluate the feature selection algorithm, and the best algorithm is selected to detect abnormal network traffic. The experimental results show that the runtime of the proposed method is 84.38% less than the original data set on the optimal feature subset selected by the proposed approach, and the average accuracy is 16.93% higher than that of the single feature selection algorithm.

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    Stability of the solution to a singularly perturbed semilinear second-order differential equation with discontinuous right-hand side
    Aleksei LIUBAVIN, Mingkang NI
    Journal of East China Normal University(Natural Science)    2022, 2022 (1): 1-9.   DOI: 10.3969/j.issn.1000-5641.2022.01.001
    Abstract194)   HTML1048)    PDF (428KB)(139)      

    In this paper, a stationary problem for the reaction-diffusion equation with a discontinuous right-hand side is considered. Based on ideas from contrast structure theory, the asymptotic representations for eigenvalues and eigenfunctions are constructed by solving a Sturm-Liouville problem and an estimation of the remainder is obtained. Moreover, a sufficient condition which guarantees the stability of the solution to this task is established.

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    New records of liverwort species in Zhejiang Province
    Ruiping SHI, Shichen XING, Xia TANG, Shuwen TU, Youfang WANG, Jian WANG
    Journal of East China Normal University(Natural Science)    2022, 2022 (1): 62-69.   DOI: 10.3969/j.issn.1000-5641.2022.01.008
    Abstract183)   HTML42)    PDF (783KB)(93)      

    To better understand the diversity of bryophytes in East China, bryophytes were systematically investigated and collected in the Huangshan - Tianmu Mountain range and Xianxia - Wuyi Mountain range in the region. In the course of field investigation, eighteen new records of liverwort species were found in Zhejiang Province, belonging to 10 families and 13 genera, respectively. Notably, Hattoria is a new genus record for Zhejiang Province. In this paper, the habitats, geographical distributions, and main identifying features of these new records are provided. Moreover, illustrations of rare and endemic liverwort species in China are presented. These new findings further enrich the bryophyte flora of Zhejiang Province and provide new basic information about the flora of the province.

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    Remote sensing inversion and time-series analysis of critical parameters for eutrophication assessment of urban waters in Shanghai
    Jiahao LI, Bo TIAN, Fang CAO, Yuekai HU, Yuanqiang DUAN, Zehao XIE, Ya PENG, Wenhao JIANG, Huifang FAN
    Journal of East China Normal University(Natural Science)    2022, 2022 (1): 135-147.   DOI: 10.3969/j.issn.1000-5641.2022.01.015
    Abstract179)   HTML35)    PDF (6823KB)(105)      

    Estuarine cities are heavily influenced by anthropogenic activities. In turn, their water bodies often face serious eutrophication and pollution problems, thereby exerting significant pressure on the urban production and living environment. This study focuses on the water bodies in the city of Shanghai, an important estuarine megacity in China. Using the Sentinel-2 satellite and in situ measured water spectrum data, we built an inversion model for rapid identification of two critical parameters for eutrophication assessment, namely chlorophyll-a concentration and turbidity. We subsequently analyzed the spatial and temporal variability of these two parameters using time-series satellite data. Our results showed that the correlation coefficient (R2) of turbidity and chlorophyll-a concentration inversion based on remote sensing was 0.95 and 0.87, respectively; the root mean square error (RMSE) was 4.33 μg/L and 8.93 NTU, respectively. Time-series analysis from 2019 showed that both chlorophyll-a concentration and turbidity in different urban water bodies were highest in the summer and lowest in the winter in Shanghai. Specifically, chlorophyll-a concentrations across water bodies decreased in the following sequence: aqua-culture/planting ponds, permanent freshwater lakes, reservoir ponds, permanent rivers, and canals/transportation rivers. In the case of turbidity, the water bodies ordered from highest to the lowest followed the sequence: aqua-culture/planting ponds, permanent rivers, canals/water delivery rivers, permanent freshwater lakes, and reservoir ponds. Time series analysis of chlorophyll-a concentrations and turbidity from 2019 showed that in water bodies with less human disturbance, the correlation between chlorophyll-a concentration and turbidity was stronger than those that were heavily influenced by anthropogenic activities. The use of Sentinel-2 satellite images to retrieve the chlorophyll-a concentration and turbidity in water bodies can generally provide information on the eutrophication status of water bodies in Shanghai; the data, moreover, can serve as a reference for aquatic environmental monitoring of inland water bodies in other cities.

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    Preparation and characterization of Ag@Au bimetallic nanoparticles
    Tianchen ZHAO, Xiaolei ZHANG, Shitao LOU
    Journal of East China Normal University(Natural Science)    2022, 2022 (1): 43-51.   DOI: 10.3969/j.issn.1000-5641.2022.01.006
    Abstract173)   HTML42)    PDF (973KB)(131)      

    Ag nanoparticles were first prepared using a seed-based thermal synthetic procedure. The monometallic particles were then transformed into bimetallic particles via a galvanic replacement reaction. A transmission electron microscope (TEM), scanning transmission electron microscope (STEM), and absorption spectrum were subsequently used for characterization. By controlling the amount of seed added, the ultrasonic exposure, and the centrifugal time, we can effectively tune the size of the particles and the localized surface plasmon resonance peak positions. The TDBC film can be wrapped on the surface of the metallic nanostructures by a ligand exchange reaction to achieve strong coupling between surface plasmon and molecular excitons.

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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
    Abstract172)   HTML40)    PDF (942KB)(160)      

    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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    The decycling number of join graphs
    Hongbo YE, Chao YANG, Fuxiang CUI
    Journal of East China Normal University(Natural Science)    2022, 2022 (1): 17-21.   DOI: 10.3969/j.issn.1000-5641.2022.01.003
    Abstract171)   HTML841)    PDF (2052KB)(68)      

    Let $G = (V, E)$ be a simple graph. For any vertex set $S$ of V, if $G - S$ is acyclic, then $S$ is a decycling set of G; the minimum size of a decyling set is called the decycling number of G, denoted by $\phi \left( G \right)$ . In this paper, we consider the decycling problem of join graphs and obtain the exact value for the decycling number of some types of join graphs. Let ${G_m}$ and ${G_n}$ be simple connected graphs of the order m and n, respectively. Then the decycling number of the join graph ${G_m} \vee {G_n}$ satisfies: $\min \{ m,n\} \leqslant \phi ({G_m} \vee {G_n}) \leqslant $ $ \min \{ m + \phi ({G_n}),n + \phi ({G_m})\}$ . The results presented in this paper confirm that the upper bound for the above inequality is tight. In particular, if ${G_m}$ and ${G_n}$ are trees, then we can obtain the exact value for the decycling number of ${G_m} \vee {G_n}$ .

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    A fast key points matching method for high resolution images of a planar mural
    Xinye ZHANG, Weiqing TONG, Haisheng LI
    Journal of East China Normal University(Natural Science)    2021, 2021 (6): 65-80.   DOI: 10.3969/j.issn.1000-5641.2021.06.008
    Abstract169)   HTML59)    PDF (2053KB)(43)      

    Existing methods of key points matching were invented for grayscale images and are not suitable for high resolution images. Mural images typically have very high resolution, and there may be areas with the same gray textures and different colors. For this special kind of image, this paper proposes a high-speed algorithm of key points matching for high-resolution mural images (NeoKPM for short). NeoKPM has two main innovations: (1) first, the homography matrix of rough registration for the original image is obtained by downsampling the image, which substantially reduces the time required for key points matching; (2) second, a feature descriptor based on gray and color invariants is proposed, which can distinguish different colors of texture with the same gray level, thereby improving the correctness of key points matching. In this paper, the performance of the NeoKPM algorithm is tested on a real mural image library. The experimental results show that on mural images with a resolution of 80 million pixels, the number of correct matching points per pair of images is nearly 100 000 points higher than that of the SIFT (Scale Invariant Feature Transform) algorithm, the processing speed of key points matching is more than 20 times faster than that of the SIFT algorithm, and the average error of dual images based on a single pixel of the image is less than 0.04 pixels.

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    SQLite-CC based on non-volatile memory cache
    Yaoyi HU, Huiqi HU, Xuan ZHOU, Aoying ZHOU
    Journal of East China Normal University(Natural Science)    2021, 2021 (6): 124-134.   DOI: 10.3969/j.issn.1000-5641.2021.06.013
    Abstract169)   HTML56)    PDF (999KB)(132)      

    In recent years, non-volatile memory (NVM) has developed rapidly. Its advantages, among others, include: persistence, large capacity, low latency, byte addressing, high density, and low energy consumption — all of which have impacted current database system architecture. SQLite is a lightweight relational database widely used in embedded fields such as mobile platforms. It operates as a serverless, zero-configuration, transactional SQL database engine. It maintains a cache for each connection, which results in problems with large space overhead and data consistency detection. At the same time, it adopts a relatively simple serialized single-write transaction execution method and page-based logging, which offers low performance and write amplification in the journal mode and a storage space requirement in the WAL mode during execution. In order to address the above challenges, a new scheme of SQLite Cache based on non-volatile memory, SQLite-CC (Copy Cache), is constructed, which fully considers the hardware characteristics of non-volatile memory and ensures the atomicity of transactions using a CC-manager and by adding an updated page index to ensure the consistency of database files and cache. Benchmarking tests show that it can achieve the same concurrency performance as SQLite-WAL mode. Compared with the rollback mode, it improves the execution performance of transactions by 3 times, reduces latency by 40%, and effectively solves the issue of write amplification on disks.

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    Braided vector algebra $ V(R',R) $
    Hongmei HU
    Journal of East China Normal University(Natural Science)    2021, 2021 (6): 33-37.   DOI: 10.3969/j.issn.1000-5641.2021.06.004
    Abstract166)   HTML49)    PDF (472KB)(33)      

    Braided vector algebras are an important class of Hopf algebras in braided tensor categories. In this paper, it is shown that braided vector algebras are isomorphic to quantum vector spaces as associative algebras; hence, the algebraic structure of braided vector algebras and three equalities of the pair $ (R',R)$ are recovered from representations of quantized enveloping algebras $ U_q(\mathfrak g)$ .

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    Two new records of epiphyllous Cheilolejeunea species recorded in Zhejiang Province
    Shichen XING, Zun DAI, Xing CHEN, Jian WANG
    Journal of East China Normal University(Natural Science)    2022, 2022 (1): 70-75.   DOI: 10.3969/j.issn.1000-5641.2022.01.009
    Abstract165)   HTML40)    PDF (805KB)(60)      

    Two epiphyllous species, namely Cheilolejeunea chenii and C. obtusilobula, were newly recorded in Zhejiang Province. The specimens were collected from Gaoshanwan Village, Yushang Township, Qingyuan County, Zhejiang Province. It is worth noting that C. chenii has a very narrow distribution range in China and is a particularly rare species that should be protected as soon as possible. In this paper, the morphological characteristics, distribution, and habitats of the two species are briefly described and discussed. Given that the two species are not currently within the protection scope of the nature reserve, we also propose new ideas for in-situ conservation of epiphyllous liverworts.

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