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Table of Content

    28 June 2021, Volume 49 Issue 3
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    Research on Thermal Runaway Behavior of High-Energy-Density 21700 Lithium-Ion Batteries
    YANG Kun，ZHANG Shiyi，CHEN Long，WANG Guigang，LIN Zhiwei，LEI Hongjun，XIAO Bowen，XU Rui，CHENG Xin，ZHENG Yun，LIU Zhihong
    2021, 49(3):  5-12.  doi:10.16389/j.cnki.cn42-1737/n.2021.03.001
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    The safety of lithium-ion batteries is very important. In this study，the adiabatic rate calorimeter was used to explore the thermal runaway behavior of 21700 lithium-ion batteries with states of charge（SOC） of 0%，25%，50%，75% and 100% respectively. Meanwhile，the thermal stability of the separator was analyzed. It was demonstrated that with the increasing of SOC，the onset temperature of side reaction was lower，the initial temperature point of the thermal runaway was lower，and the maximum temperature was higher. The higher the SOC，the higher the temperature rise rate when thermal runaway occurred，the more violent the reaction，and the more mass loss. The results showed that the internal short circuit caused by the separator melting was not the underlying reason for the thermal runaway of lithium-ion batteries. The heat released by the short circuit would accelerate the occurrence of side reactions. The underlying reason for the thermal runaway is the reaction between the electrode material and electrolyte， and the heat released by subsequent exothermic side reactions.
    Numerical Characterization of the Micro- or Nanopatterning Formation Induced by an Electric Field
    HAN Zhiliang，LIU Xueqing
    2021, 49(3):  13-20.  doi:10.16389/j.cnki.cn42-1737/n.2021.03.002
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    With the rapid development of optoelectronic devices，polymer with micro- or nanopatterning has been widely used due to their unique physical and chemical properties. The technology of polymer rheology induced by a spatially modulated electric field is an important method for fabricating polymer micro- or nanopatterning and has been widely used. In this paper，the principle of processing polymer microstructure was discussed. A numerical approach for visualizing the full evolution of micro- or nanopatterning based on COMSOL Multiphysic was established，and the effect of the parameters such as electrode width and voltage，dimension of air space on the pattern formation were analyzed. Results showed that enlarging the electrode width and increasing the voltage could promote microstructure formation. When the air gap was fixed，reducing the film thickness helped the formation of microstructure. In addition，the numerical results of the phase-field method were better to agree with experimental observations，in comparison with the results of the level set method.
    Preparation and Thermal Properties of Mixed Diamine Monomer Polyimide Containing Isomer
    CAI Cai，WANG Gang，LU Chunyan，LIU Jiyan，HU Siqian
    2021, 49(3):  21-27.  doi:10.16389/j.cnki.cn42-1737/n.2021.03.003
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    Using the isomeric mixture diamine monomer diethyltoluenediamine（DETDA） as the diamine raw material，using the melt polycondensation method，DETDA，4，4'- oxydiphthalic anhydride （ODPA），3，3'，4，4'-diphenylketone-tetrahydride （BTDA） was ternarily copolymerized in different proportions，and after high-temperature thermal imidization，5 kinds of DETDA/ODPA/BTDA molding powder were obtained，of which 3 kinds of molding powder can be dissolved in N，N-dimethylformamide（DMF）and coated to form a film. Then the structure，thermal properties of 5 kinds of molding powders and films were tested. The results showed that these molding powders were easy to process， and the five molding powders and films had excellent thermal properties.
    Effects of Nitrogen Application Level and Planting Density on Wheat Yield and Grain Quality
    WEI Peng，YUAN Jianxin，WANG Lingling，YAN Suhui
    2021, 49(3):  28-34.  doi:10.16389/j.cnki.cn42-1737/n.2021.03.004
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    In order to explore the regulation effects of the interaction of nitrogen application level and planting density on wheat yield and grain quality ， two main wheat varieties ' Ningmai13' （NM13） and ' Wanximai0638'（W38） in the Jianghuai region were used as materials，and a split-split-block design was adopted，with the main zone being varieties， the split area being nitrogen fertilizer treatment，and the split-split area being planting density. Set 3 nitrogen levels of pure nitrogen application at 120 kg/hm2（N1），180 kg/hm2 （N2），240 kg/hm2（N3），and three density gradients of 1. 8 million plants/hm2（D1）， 2. 4 million plants/hm2（D2），3 million plants/hm2（D3），to study the effects of different nitrogen levels and planting densities on wheat yield and related factors，as well as the effects on grain protein content，wet gluten content and sedimentation value and other grain quality. The results showed that with the increase of nitrogen application rate，the number of ears， grains per ear，and wet gluten content showed an upward trend，the thousand-grain weight first decreased and then increased，and the yield，protein content and sedimentation value increased first and then decreased. With the increase of planting density，the number of ears showed an upward trend，the number of ears，thousand-grain weight，and sedimentation value showed a downward trend. The content of protein and wet gluten showed a decline first and then an upward trend，and the yield showed a first rise and then a decline. The yield of wheat was highest when the nitrogen application rate was 180 kg/hm2 and the planting density was 2. 4 million plants/hm2. However，under this cultivation condition，the grain protein content and wet gluten content were lower than the cultivation condition of the nitrogen application rate being 180 kg/hm2 and the planting density was 3 million plants/hm2. Under the latter cultivation conditions，the yield of wheat was relatively high，and the performance of the two varieties was consistent. It can be seen that in order to obtain high-quality and highyield cultivation，' Ningmai13' and ' Wanximai0638' in the Jianghuai area are suitable for planting under the conditions of 180 kg/hm2 nitrogen application rate and 3 million plants/hm2 planting density.
    Fruit Quality Analysis of ′Jiangda Purple Pepper′
    HE Bingbing，WAN Heping，OUYANG Jingmei，GUO Rui，HUANG Benliang，CHEN Chanyou
    2021, 49(3):  35-40.  doi:10.16389/j.cnki.cn42-1737/n.2021.03.005
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    Using 'Jiangda Purple Pepper No.1' and 'Jiangda Purple Pepper No.2' as research materials，the main appearance and quality characteristics of pepper fruits in three periods， namely， green ripening period， purple ripening period and red ripening period were determined. The results showed that the average fruit length of 'Jiangda Purple Pepper No.1' was 18. 09 cm，the average fruit weight was 44. 29 g，the average pulp thickness was 3. 20 mm， and the average fruit hardness was 33. 78 N. Its vitamin C content was the highest in the green ripening period， reaching 52. 76 mg/100g， and the average anthocyanin content measured during the purple ripening period was 4. 46 mg/100g. The average fruit length of ' Jiangda Purple Pepper No. 2' was 12. 35 cm，the average fruit weight was 13. 48 g，the average pulp thickness was 1. 91 mm，and the average fruit hardness was 62. 73 N. Its vitamin C content was the highest in the green ripening period，reaching 58. 02 mg/100 g， and the average anthocyanin content measured in the purple ripening period was 1. 62 mg/100g. The results of this study provide an experimental basis for the selection of highanthocyanin-content high-quality varieties，and provide certain data references for the promotion of 'Jiangda Purple Pepper' varieties.
    Effects of Water Hyacinth（Eichhornia crassipes）Invasion on Methane Emission in Lake Wetland
    ZHOU Wenchang，SHI Yuhu，SUN Xiaoxin，FU Tian，PANG Hongdong
    2021, 49(3):  41-48.  doi:10.16389/j.cnki.cn42-1737/n.2021.03.006
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    The lake wetland is a significant natural source of methane emission，accounting for 4% - 47% of global natural methane emissions. The invasion of alien plants could change the environmental factors in the lake wetlands， and subsequently， cause great changes in methane emission，which have greatly increased the uncertainty of the methane emission predictions in China's wetlands under the background of global changes. Taking the water hyacinth as an example，we synthetically analyzed the impact characteristic of water hyacinth invasion on methane emission from lake wetlands，and importantly stated the effect of the changing environmental and biological factors on the methane emission when water hyacinth invaded lake wetlands. In addition， we analyzed the changes of the methane production， oxidation， and plant transport mechanisms in lake sediments with water hyacinth invasion， which in turn affected the key process of methane emission in lake wetlands. Finally，we propounded some scientific problems of the methane emission when water hyacinth invaded lake wetlands.
    Research Progress on Impacts of Phyllostachys edulis Expansion on Forest Ecology and Its Control
    CHENG Mingsheng，ZOU Na
    2021, 49(3):  49-55.  doi:10.16389/j.cnki.cn42-1737/n.2021.03.007
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    As a typical vegetation of subtropical forests， Phyllostachys edulis brings economic benefits，but at the same time，the phenomenon of expansion and invasion has intensified，and it has a certain destructive effect on the stability of the forest ecosystem. This article mainly describes the adverse effects of Phyllostachys edulis expansion on plants，soil，and community climate in the forest ecosystem. It summarizes the effective methods to inhibit Phyllostachys edulis expansion from the three aspects of physical harvesting，abiotic stress，and nitrogen absorption， in order to provide feasible and effective control methods for Phyllostachys edulis expansion and maintain the ecological balance of the forest system.
    Research on Feature Extraction and Evaluation of Mixed Data Based on Sparse Convex Non-Negative Matrix Factorization
    ZHOU Jing，YU Chao，HU Yiyu，DU Qianqian
    2021, 49(3):  56-63.  doi:10.16389/j.cnki.cn42-1737/n.2021.03.008
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    Aiming at the lack of fusion analysis on the mixed data of online teaching and traditional classroom， the improved sparse convex non-negative matrix factorization algorithm was used to effectively extracting the feature clusters of student learning behavior data. Based on the weights of cluster features，multi-level feature indicators were selected in turn to construct a PSR evaluation index system on three levels of evaluation layer，cluster layer and feature layer. According to the evaluation index system，the quality value of individuals was calculated based on the comprehensive weighting method，and students were graded. The grading results were in accordance with the normal distribution and basically consistent with the grading distribution of students' final examination scores. Thus the validity of the model and method proposed in this paper is proved.
    Research on Blueberry Fruit Grading Based on Machine Vision
    LI Jianhang，YI Kechuan，LIU Lang，ZHANG Xinwei，SUN Yerong
    2021, 49(3):  64-69.  doi:10.16389/j.cnki.cn42-1737/n.2021.03.009
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    In view of the low efficiency of the traditional sorting method of blueberry fruit，the digital recognition and calculation of the projection area of blueberry fruit were proposed by using machine vision technology. The image of blueberry fruit was divided by the maximum inter-class variance method，the connected domain area was removed by morphological processing method，the blueberry area was approximately rounded by the least-square method，and the area and perimeter of blueberry fruit were calculated after calibration. The results showed that in the case of manual segmentation results as the standard for calculating relative accuracy，the use of the blueberry area as the grading standard was more accurate than the use of perimeter as the grading standard，and the effect was better. After the image processing，the average accuracy of the calculated area reached 98. 93%，the effect was stable，with high accuracy. It provides an important basis for the automatic grading of blueberry fruit.
    Analysis of Clinical Selection Patterns of Acupuncture Points for Smoking Cessation Based on Data Mining Technology
    ZHANG Lei，YANG Tingyuan，LI Mengying，WANG Changyuan，YE Jingrong，ZHU Shuxiu
    2021, 49(3):  70-78.  doi:10.16389/j.cnki.cn42-1737/n.2021.03.010
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    Objective To analyze the clinical acupoint selection rule and characteristics of acupuncture for smoking cessation based on data mining technology. Methods The literature on acupuncture for smoking cessation collected and published by CNKI，Wanfang and VIP database from the establishment of the database until July 1，2020 were retrieved，and the acupoint information of acupuncture prescription was collected. TCMISS V2.5 was used to analyze the data. Results A total of 36 articles were collected，including 37 acupuncture prescriptions and involving 40 acupoints，which mainly belonged to the stomach meridian and the large intestine meridian. Among them，there were 10 acupoints with a frequency of ≥ 5 times. The top 5 acupoints were 21 times of Zusanli（ST36），17 times of Hegu（LI4），17 times of Baihui（GV20），16 times of Sweet acupoints and 12 times of Shenmen（HT7）. There were 17 commonly used acupoint combinations with a frequency of ≥ 6. The top 5 acupoint combinations were Shenmen （HT7） -Sweet acupoint， Zusanli （ST36）-Sanyinjiao （SP6），Zusanli （ST36）-Sweet acupoint，Hegu （LI4）-Baihui （GV20），and Zusanli （ST36）-Hegu （LI4）. Six acupoint combinations and three new acupoint prescriptions were obtained based on the entropy clustering algorithm. Conclusion The main meridians of acupuncture for smoking cessation are stomach meridian， large intestine meridian and Du-meridian. The acupoints are based on Zusanli（ST36），Sweet acupoints and Shenmen（HT7）. The use of specific acupoints mainly focuses on intersection acupoints，Wushu acupoints and original acupoints，paying attention to the use of Sweet acupoints with experience.
    Comparison of Different Anesthesia Methods in Ultrasound-Guided Percutaneous Transluminal Angiography Therapy
    YU Yang，LIU Wei，DENG Youbin，YE Lei
    2021, 49(3):  79-83.  doi:10.16389/j.cnki.cn42-1737/n.2021.03.011
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    Objective To compare the analgesic effect of different anesthetic methods in ultrasound-guided percutaneous transluminal angiography （PTA） therapy for dialysis arteriovenous fistula （AVF） stenosis. Methods Ultrasound-guided PTA was performed on 93 hemodialysis patients with AVF stenosis from October 2017 to July 2019. Patients were randomized into four groups：no anesthesia group（n = 20），surface anesthesia group （n = 27），local infiltration anesthesia（n = 22），high selective local nerve block anesthesia group（n = 24），to observe the anesthesia effect，the operating time（including onset and duration）and the postoperative complications. Results The pain score of the no anesthesia group and surface anesthesia group were significantly higher than the other two groups. The pain score of the no anesthesia group was the highest，which was significantly higher than that of the other anesthesia groups. The pain score of the surface anesthesia group was in the middle，which was significantly higher than that of the highly selective local nerve block group and the local infiltration anesthesia group. There was no significant difference in pain score between the highly selective local nerve block group and the local infiltration anesthesia group. In terms of anesthesia time，the highly selective local nerve block group had the longest operation time， which significantly prolonged the operation time. During the observations of postoperative complications，one case of local erythema occurred in the surface anesthesia group，two cases of blood vessel injuries occurred in the local infiltration anesthesia，and one case of intramuscular hematoma occurred in the highly selective local nerve block group. Conclusion Local infiltration anesthesia and high selective local nerve block anesthesia are well tolerated for patients' surgical pain，but should be noted to avoid complications. Although the two groups have obviously better analgesic effects，in the highly selective local nerve block group，the operation time has markedly prolonged. Surface anesthesia has limited analgesic effects， and could be used for patients who are fewer sensitive to pain. There are no severe complications in the three anesthetic methods.
    Study on the Age of Initiation of Sexual Development and Gonadotropin Level in Children with Idiopathic Short Stature
    DUAN Mengting，LI Ruizhen
    2021, 49(3):  84-90.  doi:10.16389/j.cnki.cn42-1737/n.2021.03.012
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    Objective To investigate the onset age of sexual development in children with idiopathic short stature，to study the gonadotropin levels in children with idiopathic short stature of different gender and age，and to explore whether the gonadotropin-releasing hormone（GnRH）stimulation test can be simplified. Methods The clinical data of children with idiopathic short stature who were hospitalized in the Department of Endocrinology of Wuhan Children's Hospital from 2013 to 2020 were retrospectively collected. The median ages of female breast developing to B2 stage and male testicular developing to 4 mL were calculated. The differences of basic value，30，60，90，120 min and peak value of luteinizing hormone（LH）and follicle stimulating hormone（FSH）in GnRH stimulation test of different gender，age and sexual developing stage were analyzed，and the differences of results at different measurement time points were compared. Results ① The median age of female breast developing to B2 stage was 10. 42 years old，and the median age of male testicular development to 4 mL was 12. 08 years old. ② The peak value of LH in boys increased significantly at 9 years old，and the mean value of peak value was more than 5 mIU/mL at 10 years old，the peak value of LH in girls increased significantly around 10 years old. The basic value of LH in both boys and girls increased significantly at 11 years old. The basic value of FSH increased gradually from school age. The peak value of FSH decreased with the increase of age in girls，and was higher than that of males in all age groups. ③ Regardless of sex development，the LH average value of girls was the highest at 30 min，and that of boys was the highest at 60 min. There was no significant difference between 90 and 120 min （P = 0. 095 in prepuberty group and P = 1 in puberty group）. The highest mean value of FSH in girls was at 60 or 90 min，and there was no significant difference between 60 and 90 min（P = 1 in prepuberty group and P = 0. 225 in puberty group）. Conclusion ① The onset age of puberty in children with idiopathic short stature is about 10. 42 years old for girls and 12. 08 years old for boys，which is slightly later than the previous large-scale survey data of healthy children. ② In the GnRH stimulation test，the peak of LH mostly appeared in 30 - 60 min，while the peak of FSH mostly appeared in 60 - 120 min. No matter male or female and no matter what the sexual development stageis，the values of LH at 30 min and LH at 60 min can better reflect the peak level of LH，and the value of FSH at 90 min can better reflect the peak level of FSH. ③ The GnRH stimulation test was simplified to 0，30，60 and 90 min，which could well reflect the peak of LH and FSH.
    Anti-NMDAR Encephalitis with Insomnia：A Case Report and Literature Review
    YOU Hong，CHEN Guohua
    2021, 49(3):  91-96.  doi:10.16389/j.cnki.cn42-1737/n.2021.03.013
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    Objective To investigate the clinical manifestation，diagnosis and treatment of anti-N-methyl-D-aspartate receptor encephalitis （anti-NMDAR encephalitis）. Methods The clinical manifestations， imaging， cerebrospinal fluid， polysomnography （PSG），diagnosis and treatment of 1 case of Anti-NMDAR encephalitis were reported， combined with the literature review. Results The patient had clinical manifestations such as insomnia， blurred vision， fever， abnormal sensation， and slow response， and anti-NMDAR encephalitis antibody IgG was detected in the cerebrospinal fluid，which met the diagnostic criteria of anti-NMDAR encephalitis. The patient with hormone combined with immunoglobulin treatment achieved good results. Conclusion When the clinical symptoms of anti-NMDAR encephalitis are atypical，it is easy to miss the diagnosis. Even if no abnormality is found in the brain MRI，autoimmune encephalitis detection of the cerebrospinal fluid should be detected actively. The treatment of hormone with immunoglobulin should be performed after the early diagnosis to improve the prognosis of the patient，and long-term follow-up should be carried out.