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Distortion-Free Zeeman Torque Sampling for Detecting Terahertz Magnetic Field Pulse
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作者 Chun-yan Geng Yi-chen Su +3 位作者 De-yin Kong fei dai Cheng-song Xiao-jun Wu 《Chinese Physics Letters》 2025年第11期383-392,共10页
Strong-field terahertz(THz) radiation holds significant potential in non-equilibrium state manipulation, electron acceleration, and biomedical effects. However, distortion-free detection of strong-field THz waveforms ... Strong-field terahertz(THz) radiation holds significant potential in non-equilibrium state manipulation, electron acceleration, and biomedical effects. However, distortion-free detection of strong-field THz waveforms remains an essential challenge in THz science and technology. To address this issue, we propose a ferromagnetic detection scheme based on Zeeman torque sampling, achieving distortion-free strong-field THz waveform detection in Py films. Thickness-dependent characterization(3–21 nm) identifies peak detection performance at 21 nm within the investigated range. Furthermore, by structurally engineering the Py ferromagnetic layer, we demonstrate strong-field THz detection in symmetric Ta(3 nm)/Py(9 nm)/Ta(3 nm) heterostructure while simultaneously resolving Zeeman torque responses and collective spin-wave dynamics in asymmetric W(4 nm)/Py(9 nm)/Pt(2 nm)heterostructure. We calculated spin wave excitations and spin orbit torque distributions in asymmetric heterostructures, along with spin wave excitations in symmetric modes. This approach overcomes the sensitivity limitations of conventional techniques in strong-field conditions. 展开更多
关键词 distortion free detection terahertz magnetic field ferromagnetic detection scheme py films strong field terahertz radiation zeeman torque sampling biomedical effects electron acceleration
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基于全基因组测序对双重耐药幽门螺杆菌外排泵基因变异的研究
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作者 叶淑芳 张剑美 +5 位作者 代飞 蓝陈菊 章小君 周丽珍 汤清清 孟飞 《世界华人消化杂志》 CAS 2021年第9期455-460,共6页
背景世界上50%以上的人口感染幽门螺杆菌(Helicobacter pylori,H.pylori).随着抗生素的广泛使用,抗生素耐药成为H.pylori感染患者根除失败的主要原因.目前有不少研究报道外排泵基因过表达和耐药的产生相关.目的为了未来的H.pylori感染... 背景世界上50%以上的人口感染幽门螺杆菌(Helicobacter pylori,H.pylori).随着抗生素的广泛使用,抗生素耐药成为H.pylori感染患者根除失败的主要原因.目前有不少研究报道外排泵基因过表达和耐药的产生相关.目的为了未来的H.pylori感染治疗有更多方法,探索外排泵基因的变异与双重耐药菌株耐药性产生的内在联系.方法使用^(13)C呼气试验及药物敏感试验进行双重耐药菌株及敏感菌株的筛选,用特异性PCR的常规方法进行耐药基因突变位点的验证,基于MiSeq平台,对10例临床菌株进行全基因组测序,以鉴定双重耐药表型与敏感表型的外排泵基因的单核苷酸变体(single nucleotide variants,SNV)并分析,参考菌株使用ATCC26695.结果H.pylori药敏试验结果显示,丽水地区H.pylori对克拉霉素及左氧氟沙星都具有较高的耐药率.采用特异性PCR法在5株临床双重耐药菌株中检测到23S rRNA基因及gyrA的点突变,在5株临床敏感菌株中未检测到.全基因测序检测了涉及多耐药性的TolC同源物的四个基因簇(HP0605-HP0607,HP0971-HP0969,HP1327-HP1329和HP1489-HP1487)的遗传变异.在双重耐药性H.pylori菌株中发现一个突变的SNV.结论丽水地区抗生素使用应严格监控,避免滥用.TolC同源基因的基因簇与H.pylori菌株的抗生素耐药性相关.全基因组测序对基因型与表型的关系有了新的认识. 展开更多
关键词 双重耐药菌株 幽门螺杆菌 全基因组测序 耐药性 外排泵基因
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基于图像和飞行时间的基础设施三维重建技术比较 被引量:2
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作者 蔡建国(译) fei dai +1 位作者 Abbas Rashidi loannis Brilakis 《四川建材》 2021年第2期39-45,共7页
竣工空间数据在众多与建筑相关的应用方面颇为实用,例如质量控制和进度监控。这些数据可以通过使用多种基于图像和基于飞行时间的(例如激光扫描)传感器法来收集。每种应用都对数据的精度和质量水平有特定要求,但几乎没有什么信息可以帮... 竣工空间数据在众多与建筑相关的应用方面颇为实用,例如质量控制和进度监控。这些数据可以通过使用多种基于图像和基于飞行时间的(例如激光扫描)传感器法来收集。每种应用都对数据的精度和质量水平有特定要求,但几乎没有什么信息可以帮助工程师选择最具成本效益的数据收集方法。本文对摄影测量法、摄像测量法和基于飞行时间法在精度、质量、时间效率和成本方面进行了分析和定量比较。为此,对具有代表性的基于图像的三维重建软件和商用硬件(两台相机和一台飞行时间激光扫描仪)进行了评价。使用不同的设置收集了典型基础设施(2座桥梁和1栋楼)的空间数据。实验参数包括成像传感器的相机类型、分辨率和拍摄距离。通过将这些数据与全站仪收集的地面实况进行比较,发现摄像/摄影测量可以产生中等精度和质量的结果,但成本比激光扫描低得多。所获得的信息有助于工程师做出具有成本效益的决策,并帮助研究人员更好地了解这些设置对传感器技术的性能影响。 展开更多
关键词 三维重建 空间数据收集 激光扫描 摄影测量 摄像测量 测量精度 比较研究
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Alcohol consumption and metabolic syndrome among Shanghai adults: A randomized multistage stratified cluster sampling investigation 被引量:13
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作者 Jian-Gao Fan Xiao-Bu Cai +3 位作者 Lui Li Xing-Jian Li fei dai Jun Zhu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第15期2418-2424,共7页
AIM: To examine the relations of alcohol consumption to the prevalence of metabolic syndrome in Shanghai adults. METHODS: We performed a cross-sectional analysis of data from the randomized multistage stratified clust... AIM: To examine the relations of alcohol consumption to the prevalence of metabolic syndrome in Shanghai adults. METHODS: We performed a cross-sectional analysis of data from the randomized multistage stratified cluster sampling of Shanghai adults, who were evaluated for alcohol consumption and each component of metabolic syndrome, using the adapted U.S. National Cholesterol Education Program criteria. Current alcohol consumption was defined as more than once of alcohol drinking per month. RESULTS: The study population consisted of 3953 participants (1524 men) with a mean age of 54.3 ± 12.1 years. Among them, 448 subjects (11.3%) were current alcohol drinkers, including 405 males and 43 females. After adjustment for age and sex, the prevalence of current alcohol drinking and metabolic syndrome in the general population of Shanghai was 13.0% and 15.3%, respectively. Compared with nondrinkers, the prevalence of hypertriglyceridemia and hypertension was higher while the prevalence of abdominal obesity, low serum high-density-lipoprotein cholesterol (HDL-C) and diabetes mellitus was lower in subjects who consumed alcohol twice or more per month, with a trend toward reducing the prevalence of metabolic syndrome. Among the current alcohol drinkers, systolic blood pressure, HDL-C, fastingplasma glucose, and prevalence of hypertriglyceridemia tended to increase with increased alcohol consumption. However, low-density-lipoprotein cholesterol concentration, prevalence of abdominal obesity, low serum HDL-C and metabolic syndrome showed the tendency to decrease. Moreover, these statistically significant differences were independent of gender and age.CONCLUSION: Current alcohol consumption is associated with a lower prevalence of metabolic syndrome irrespe- ctive of alcohol intake (g/d), and has a favorable influence on HDL-C, waist circumference, and possible diabetes mellitus. However, alcohol intake increases the likelihood of hypertension, hypertriglyceridemia and hyperglycemia. The clinical significance of these findings needs further investigation. 展开更多
关键词 ALCOHOL Metabolic syndrome OBESITY Type2 diabetes Epidemiology Chinese
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Effects of Different Analog Water-soluble Fertilizers on Flue-cured Tobacco 被引量:3
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作者 fei dai Xiquan LI +1 位作者 Yuan XUE Xingping YANG 《Agricultural Science & Technology》 CAS 2017年第10期1904-1907,1920,共5页
This study aimed to investigate the application effect of analog water-soluble fertilizer as an alternative of flue-cured tobacco-specific topdressing fertilizer. A field experiment was conducted, and the dry matter a... This study aimed to investigate the application effect of analog water-soluble fertilizer as an alternative of flue-cured tobacco-specific topdressing fertilizer. A field experiment was conducted, and the dry matter accumulation, intrinsic chemical composition, smoking quality and economic benefit of flue-cured tobacco were compared between analog water-soluble fertilizer and conventional fertilizer, The results showed compared with conventional fertilizer, analog water-soluble fertilizer increased the dry matter accumulation in flue-cured tobacco by 4.90%-16.70%, increased the yield of flue-cured tobacco by 6%-15%, and increased the output of flue-cured tobacco by 5%-14%. In terms of chemical composition, the flue-cured tobacco applied with analog water-soluble fertilizer was better than that applied with conventional fertilizer, except the nicotine content in the upper leaves, the potassium content in the middle leaves and the reducing sugar content. The smoking quality of both the upper and middle leaves of flue-cured tobacco in the analog water-soluble fertilizer treatment groups was better than that in the conventional fertilizer treatment group. In short, analog water-soluble fertilizer was better than conventional fertilizer, with advantages of lower cost (reduced by 381.60 yuan/hm2), lower application amount (reduced by 165 kg/hm2) and higher utilization efficiency. 展开更多
关键词 Analog water-soluble fertilizer Flue-cured tobacco EFFECT STUDY
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Toxicity Test of Different Pesticides on Tobacco Root-knot Nematodes 被引量:2
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作者 fei dai Peibo LI +1 位作者 Quan ZHANG Enfa CHEN 《Agricultural Biotechnology》 CAS 2020年第5期86-89,共4页
[Objectives]This study was conducted to quickly screen out effective and safe agents for controlling tobacco root knot nematode disease.[Methods]Six pesticides were tested and screened indoors at five different concen... [Objectives]This study was conducted to quickly screen out effective and safe agents for controlling tobacco root knot nematode disease.[Methods]Six pesticides were tested and screened indoors at five different concentrations.[Results]The six pesticides all had toxic effects on the second-instar larvae of tobacco root-knot nematode,and the corrected mortality was positively correlated with the concentration and time of the pesticides,with the correlation coefficients above 0.8.From the perspective of inhibitory activity,the order was fosthiazate>abamectin>emamectin benzoate>cadusafos>ethoprophos>carbosulfan.Four pesticides that can be used in the field were selected.[Conclusions]This study provides a theoretical basis for field pesticide selection. 展开更多
关键词 TOBACCO Root-knot nematode Medicament Virulence determination SCREENING
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Analyzing and relieving the thermal issues caused by fabrication details of a deuterium cryogenic target 被引量:1
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作者 Hong Yang Shasha Gao +8 位作者 Baibin Jiang Jun Xie Juxi Liang Xiaobo Qi Kai Wang Chaoyou Tao fei dai Wei Lin Juan Zhang 《Matter and Radiation at Extremes》 SCIE CAS CSCD 2021年第5期39-53,共15页
In inertial confinement fusion experiments,fuel quality is determined mainly by the thermal environment of the capsule in the layering procedure.Owing to the absence of a radial thermal gradient,formed deuterium–deut... In inertial confinement fusion experiments,fuel quality is determined mainly by the thermal environment of the capsule in the layering procedure.Owing to the absence of a radial thermal gradient,formed deuterium–deuterium(DD)ice shells in the capsule are thermally instable.To obtain a solid DD layer with good quality and long lifetime,stringent demands must be placed on the thermal performance of cryogenic targets.In DD cryogenic target preparation,two issues arise,even after the capsule’s temperature uniformity has been improved by the use of thick aluminized films.The first is the inconsistent ice shape,which is related to the capsule’s thermal field.In this article,some typical fabrication details are investigated,including adhesive penetration during assembly,the presence of the fill tube,the optical properties of the hohlraum and film surfaces,the jacket–hohlraum connection,deviations in capsule location,and asymmetrical contact at the arm–jacket interfaces.Detailed comparisons of the thermal effects of these factors provide guidance for target optimization.The second issue is the instability of seeding crystals in the fill tube due to unsteadiness of the direction of the thermal gradient in the fill tube assembly.An additional thermal controller is proposed,analyzed,and optimized to provide robust controllability of tube temperature.The analysis results and optimization methods presented in this article should not only help in dealing with thermal issues associated with DD cryogenic targets,but also provide important references for engineering design of other cryogenic targets. 展开更多
关键词 temperature field THERMAL
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Data Masking for Chinese Electronic Medical Records with Named Entity Recognition 被引量:1
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作者 Tianyu He Xiaolong Xu +3 位作者 Zhichen Hu Qingzhan Zhao Jianguo dai fei dai 《Intelligent Automation & Soft Computing》 SCIE 2023年第6期3657-3673,共17页
With the rapid development of information technology,the electronifi-cation of medical records has gradually become a trend.In China,the population base is huge and the supporting medical institutions are numerous,so ... With the rapid development of information technology,the electronifi-cation of medical records has gradually become a trend.In China,the population base is huge and the supporting medical institutions are numerous,so this reality drives the conversion of paper medical records to electronic medical records.Electronic medical records are the basis for establishing a smart hospital and an important guarantee for achieving medical intelligence,and the massive amount of electronic medical record data is also an important data set for conducting research in the medical field.However,electronic medical records contain a large amount of private patient information,which must be desensitized before they are used as open resources.Therefore,to solve the above problems,data masking for Chinese electronic medical records with named entity recognition is proposed in this paper.Firstly,the text is vectorized to satisfy the required format of the model input.Secondly,since the input sentences may have a long or short length and the relationship between sentences in context is not negligible.To this end,a neural network model for named entity recognition based on bidirectional long short-term memory(BiLSTM)with conditional random fields(CRF)is constructed.Finally,the data masking operation is performed based on the named entity recog-nition results,mainly using regular expression filtering encryption and principal component analysis(PCA)word vector compression and replacement.In addi-tion,comparison experiments with the hidden markov model(HMM)model,LSTM-CRF model,and BiLSTM model are conducted in this paper.The experi-mental results show that the method used in this paper achieves 92.72%Accuracy,92.30%Recall,and 92.51%F1_score,which has higher accuracy compared with other models. 展开更多
关键词 Named entity recognition Chinese electronic medical records data masking principal component analysis regular expression
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Impacts of Different Weeding Methods on Weeds Control in Tobacco Fields in Anshun City 被引量:1
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作者 fei dai Hongbo Wan +3 位作者 Huijuan dai Xiquan Li Yuan Xue Quan Zhang 《Plant Diseases and Pests》 CAS 2021年第3期4-8,共5页
[Objective] The paper was to explore weed control measures in tobacco fields in Anshun City. [Method] Different treatments on weed control were conducted in tobacco fields in Anshun City, Guizhou Province, from 2017 t... [Objective] The paper was to explore weed control measures in tobacco fields in Anshun City. [Method] Different treatments on weed control were conducted in tobacco fields in Anshun City, Guizhou Province, from 2017 to 2019. [Result] Various treatments had no negative effect on tobacco plant growth in the field, and had different degrees of control effects on five dominant weeds, including Digitaria sanguinalis, Setaria viridis, Fagopyrum dibotrys, Commelina communis and Chenopodium album. White mulching film and 50% butralin·clomazone EC 160 m L/667 m^(2) + white mulching film had the worst performance, which had extremely significant or significant differences with other treatments. There was no sig-nificant difference among most treatments, and the overall effects were comprehensive(multi-factor) treatment > double factor treatment > single factor treatment. [Conclusion] Combination control is recommended in practical tobacco production. 展开更多
关键词 Tobacco field WEED Control effect IMPACT
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Person Re-Identification with Model-Contrastive Federated Learning in Edge-Cloud Environment 被引量:1
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作者 Baixuan Tang Xiaolong Xu +1 位作者 fei dai Song Wang 《Intelligent Automation & Soft Computing》 2023年第10期35-55,共21页
Person re-identification(ReID)aims to recognize the same person in multiple images from different camera views.Training person ReID models are time-consuming and resource-intensive;thus,cloud computing is an appropria... Person re-identification(ReID)aims to recognize the same person in multiple images from different camera views.Training person ReID models are time-consuming and resource-intensive;thus,cloud computing is an appropriate model training solution.However,the required massive personal data for training contain private information with a significant risk of data leakage in cloud environments,leading to significant communication overheads.This paper proposes a federated person ReID method with model-contrastive learning(MOON)in an edge-cloud environment,named FRM.Specifically,based on federated partial averaging,MOON warmup is added to correct the local training of individual edge servers and improve the model’s effectiveness by calculating and back-propagating a model-contrastive loss,which represents the similarity between local and global models.In addition,we propose a lightweight person ReID network,named multi-branch combined depth space network(MB-CDNet),to reduce the computing resource usage of the edge device when training and testing the person ReID model.MB-CDNet is a multi-branch version of combined depth space network(CDNet).We add a part branch and a global branch on the basis of CDNet and introduce an attention pyramid to improve the performance of the model.The experimental results on open-access person ReID datasets demonstrate that FRM achieves better performance than existing baseline. 展开更多
关键词 Person re-identification federated learning contrastive learning
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Design of scale model of plate-shaped absorber in a wide frequency range
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作者 Li-Ming Yuan Yong-Gang Xu +2 位作者 Wei Gao fei dai Qi-Lin Wu 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第4期299-304,共6页
In order to design the scale model in a wide frequency range,a method based on the reflective loss is proposed according to the high-frequency approximation algorithm,and an example of designing the scale model of a p... In order to design the scale model in a wide frequency range,a method based on the reflective loss is proposed according to the high-frequency approximation algorithm,and an example of designing the scale model of a plate-shaped absorber is given in this paper.In the example,the frequency of the full-size measurement ranges from 2.0 GHz to 2.4 GHz,the thickness of the full-size absorber is 1 mm and the scale ratio is 1/5.A two-layer scale absorber is obtained by the proposed method.The thickness values of the bottom and top layer are 0.4 mm and 0.5 mm,respectively.Furthermore,the scattering properties of a plate model and an SLICY model are studied by FEKO to verify the effectiveness of the designed scale absorber.Compared with the corresponding values from the theoretical scale model,the average values of the absolute deviations in 10 GHz~12 GHz are 0.53 d Bm^2,0.65 d Bm^2,0.76 d Bm^2 for the plate model and 0.20 d Bm^2,0.95 d Bm^2,0.77 d Bm^2 for the SLICY model while the incident angles are 0°,30°,and 60°,respectively.These deviations fall within the Radar cross section(RCS) measurement tolerance.Thus,the work in this paper has important theoretical and practical significance. 展开更多
关键词 scale model plate-shaped absorber wide frequency range RCS
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Effect of Trap Space Layout on Trapped Number of Spodoptera litura in Tobacco Field
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作者 fei dai Xiquan LI +2 位作者 Xingping YANG Hao QIN Rui ZUO 《Agricultural Biotechnology》 CAS 2019年第1期93-96,共4页
[Objectives] This study was to find out the effect of trap space layout on the trapped number of Spodoptera litura in tobacco field. [Methods]From2015 to 2017,investigations were made using different hanging heights,d... [Objectives] This study was to find out the effect of trap space layout on the trapped number of Spodoptera litura in tobacco field. [Methods]From2015 to 2017,investigations were made using different hanging heights,distances( densities) and equidistant plane layout in the tobacco planting area in central Guizhou Province. [Results] The trapped number of S. litura was different at different hanging heights of the trap,and some had the difference reached the5% significant level in the trapped number. The optimum hanging height was 1. 5-2. 0 m. The trapping effect was the best at the field layout distance of20. 0-30. 0 m( density of 5-8 traps/hm^2). Under the conditions of even distribution at the equal distance between traps of 40.0 m in the field,the accumulated trapped number of S. litura from April to August was in the order of outer ring > central ring > inner ring,presenting the zonal distribution. The difference in the trapped numbers was significant among different rings,reaching the 5% significant level. [Conclusions]This study provided theoretical bases for the physiochemical control of S. litura in tobacco field. 展开更多
关键词 TRAP Tobacco field SPACE layout SPODOPTERA litura TRAPPED NUMBER EFFECT
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Detection and mitigation of RFI in SBRS observation data
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作者 Zhen-Ping Qiang Jun Cheng +3 位作者 Zhen-Hong Shang Kai-Fan Ji fei dai Hui Liu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2021年第8期111-123,共13页
In view of the inconsistency of channel gains and a large amount of interference noise in Solar Broadband Radio Spectrometer(SBRS) observation data,they will seriously affect the analysis of SBRS data.In this paper,a ... In view of the inconsistency of channel gains and a large amount of interference noise in Solar Broadband Radio Spectrometer(SBRS) observation data,they will seriously affect the analysis of SBRS data.In this paper,a method of Radio Frequency Interference(RFI) detection and mitigation for SBRS observation data is reported.Firstly,the SBRS observation data are preprocessed,a part of the observation data was selected to calculate the mean and variance to achieve the normalization of the entire observation data,which can avoid the influence of strong noise on the normalization result.Furthermore,we proposed an adaptive threshold RFI detection method based on fusion wavelet transform reconstruction and an RFI elimination method based on neighborhood weighted filling.It is worth mentioning that to detect RFI interference signals of different magnitudes,we adopted an iterative approach to the RFI detection and mitigation process.Through qualitative analysis of real observation data and quantitative analysis of simulated data,it is shown that the method proposed in this paper can effectively eliminate RFI in SBRS observation data,and improve the quality of observation data for further scientific analysis. 展开更多
关键词 spectrographs:SBRS techniques:image processing and spectroscopic Sun:radio radiation
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The lack and construction of teaching communication in Physical Education in Colleges and universities
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作者 fei dai Beilei Chen 《International Journal of Technology Management》 2016年第12期45-47,共3页
Teachers and students are the two main subjects which are indispensable in the teaching activities. Their communication is the most basic activity in the whole teaching activities. The social economy in our country is... Teachers and students are the two main subjects which are indispensable in the teaching activities. Their communication is the most basic activity in the whole teaching activities. The social economy in our country is developing and changing constantly, and the teaching reform has been changed, and it has been well developed. Physical education is a very important component in the teaching structure of colleges and universities, and the teaching of physical education has been highly concerned by people. But in the sports teaching practice, in? uenced by traditional teaching ideas and teaching skills, communication of PE Teaching in Colleges and universities appeared unilateral and simple phenomenon, directly affect the quality and efficiency of teaching. We should figure out how to avoid the lack of teaching communication in college physical education, in order to make the relationship between teachers and students, students and students more harmonious, and promote the improvement of the efficiency of sports teaching. This article mainly focus on the teaching concept, we discuss and analyze the problems and reasons in the teaching of physical education in Colleges and Universities and put forward a new sports teaching communication construction strategy, the purpose is to provide some support and help to the university physical education teaching activities. 展开更多
关键词 Physical education in Universities Teaching communication DEFICIENCY Construction strategy
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Population Genomic Analysis and De Novo Assembly Reveal the Origin of Weedy Rice as an Evolutionary Game 被引量:14
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作者 Jian Sun Dianrong Ma +18 位作者 Liang Tang Minghui Zhao Guangchen Zhangh Wenjia Wang Jiayu Song Xiang Li Zimeng Liu Wenxing Zhang Quan Xu Yuncheng Zhou Jianzhong Wu Toshio Yamamoto fei dai Yan Lei Song Li Gang Zhou Hongkun Zheng Zhengjin Xu Wenfu Chen 《Molecular Plant》 SCIE CAS CSCD 2019年第5期632-647,共16页
Crop weediness,especially that of weedy rice(Oryza sativa f.spontanea),remains mysterious.Weedy rice possesses robust ecological adaptability;however,how this strain originated and gradually formed proprietary genetic... Crop weediness,especially that of weedy rice(Oryza sativa f.spontanea),remains mysterious.Weedy rice possesses robust ecological adaptability;however,how this strain originated and gradually formed proprietary genetic features remains unclear?Here,we demonstrate that weedy rice at Asian high latitudes(WRAH)is phylogenetically well defined and possesses unselected genomic characteristics in many divergence regions between weedy and cultivated rice.We also identified novel quantitative trait loci underlying weedy-specific traits,and revealed that a genome block on the end of chromosome 1 is associated with rice weediness.To identify the genomic modifications underlying weedy rice evolution,we generated the first de novo assembly of a high-quality weedy rice genome(WR04-6),and conducted a comparative genomics study between WR04-6 with other rice reference genomes.Multiple lines of evidence,including the results of demographic scenario comparisons,suggest that differentiation between weedy rice and cultivated rice was initiated by genetic improvement of cultivated rice and that the essence of weediness arose through semi-domestication.A plant height model further implied that the origin of WRAH can be modeled as an evolutionary game and indicated that strategy-based selection driven by fitness shaped its genomic diversity. 展开更多
关键词 weedy rice POPULATION GENOMICS de novo assembly COMPARATIVE GENOMICS EVOLUTIONARY GAME
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Simulation and test on separating cleaning process of flax threshing material based on gas-solid coupling theory 被引量:20
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作者 fei dai Xuefeng Song +3 位作者 Wenjuan Guo Wuyun Zhao Fengwei Zhang Shilin Zhang 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2020年第1期73-81,I0001,共10页
In order to further clarify and improve the working performance of separating cleaning device of flax threshing material,and study the motion law and characteristics of components of flax threshing material,in this pa... In order to further clarify and improve the working performance of separating cleaning device of flax threshing material,and study the motion law and characteristics of components of flax threshing material,in this paper,numerical simulation was carried out on the separating cleaning process of flax threshing material based on CFD-DEM method.Simulation results showed that the components of flax threshing material were separated and cleaned under the influence of airflow field,meanwhile,variation curves of quantity and mean velocity of flax seeds in the separating cleaning system were obtained.By referring to streamline distribution of gas-solid coupling,the quantity variation law of components of flax threshing material with time was explored and their motion curves and variation tendency of average velocity were studied.Verification test results showed that the cleaning rate of separating cleaning device for flax threshing material was 92.66%with 1.58%of total separation loss.Compared with simulation results,the test results were 1.34%and 0.93%lower,showing that it is feasible to apply the gas-solid coupling theory and method to simulate the separating and cleaning operation of flax threshing material. 展开更多
关键词 flax threshing material separating cleaning device hydromechanics calculation discrete element numerical simulation test
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Motion simulation and test on threshed grains in tapered threshing and transmission device for plot wheat breeding based on CFD-DEM 被引量:20
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作者 fei dai Xuefeng Song +3 位作者 Wuyun Zhao Zhengsheng Han Fengwei Zhang Shilin Zhang 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2019年第1期66-73,共8页
Mechanization of field experiments is the only way to improve crop breeding and seed propagation effects.In order to further clarify and improve the working performance of tapered threshing device for plot breeding,an... Mechanization of field experiments is the only way to improve crop breeding and seed propagation effects.In order to further clarify and improve the working performance of tapered threshing device for plot breeding,and reduce the remaining seeds in the device,the numerical simulation was carried out on the motion process of materials in the longitudinal-axial tapered cylinder threshing and transmission device of the plot wheat breeding combine harvester based on CFD-DEM method.Simulation results showed that,threshing and transmission of particles and short stalks at axial direction could be realized under the influence of air flow.Meanwhile,the material transference and distribution rule and stream field distribution rule of air flow in the threshing and transmission device were obtained,the variations of velocity and displacement of particles and short stalks with time were obtained;the motion trajectories and forms of particles in different types of retention were also studied.At rotating speed of 1300-1600 r/min for the tapered threshing cylinder in the verification test,the particle retention rate in the enclosure was 0-0.13%,while in the simulation the particle retention rate in the enclosure was 0-0.11%,only a 0.02%difference between them.The results proved a favorable feasibility to simulate the working performance of the tapered threshing and transmission device for plot breeding through gas-solid coupling method. 展开更多
关键词 particle threshing and transmission tapered threshing and transmission device hydromechanics calculation discrete element numerical simulation test
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Design and field test of crosswise belt type whole plastic-film ridging-mulching corn seeder on double ridges 被引量:11
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作者 fei dai Wenjuan Guo +3 位作者 Xuefeng Song Ruijie Shi Wuyun Zhao Fengwei Zhang 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2019年第4期88-96,共9页
In order to realize seedbed mechanization of whole plastic-film mulching on double ridges and to overcome the difficulty in crosswise belt type soil covering by whole plastic-film,a kind of crosswise belt type whole p... In order to realize seedbed mechanization of whole plastic-film mulching on double ridges and to overcome the difficulty in crosswise belt type soil covering by whole plastic-film,a kind of crosswise belt type whole plastic-film ridging-mulching corn seeder on double ridges was designed in this study.The key components of the sample machine was designed and its working parameters of seedbed soil covering device,crosswise-belt soil covering mechanism and profiling sowing depth adjustment device were determined.After numerical simulation on the film edge and crosswise soil covering by whole plastic-film on double ridges by discrete element method,the velocity and displacement of the oscillating plate,and the variation rule of amount of covered soil with time were explored.Field test results show that,when the advancing velocity of the machine was 0.50 m/s,the qualified rate of soil width covered on film edge of the seedbed reached 96.1%,qualified rate of crosswise soil belt width was 94.5%,qualified rate of soil thickness on seedbed was 95.3%,qualified rate of sowing depth was 89.3%,qualified rate of spacing between crosswise soil belts reached 93.6%,which all met related standards in China and satisfied design requirements,and could realize seedbed mechanization of whole plastic-film mulching on double ridges.Comparison tests on working performances of practical soil covering show a basic consistence with the seedbed soil covering simulation,and verified the effectiveness of the soil covering model built by using discrete element method. 展开更多
关键词 whole plastic-film on double ridges crosswise belt soil covering combined machine discrete element numerical simulation field test
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Artificial Intelligence for Edge Service Optimization in Internet of Vehicles:A Survey 被引量:14
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作者 Xiaolong Xu Haoyuan Li +3 位作者 Weijie Xu Zhongjian Liu Liang Yao fei dai 《Tsinghua Science and Technology》 SCIE EI CAS CSCD 2022年第2期270-287,共18页
The Internet of Vehicles(IoV)plays a crucial role in providing diversified services because of its powerful capability of collecting real-time information.Generally,collected information is transmitted to a centralize... The Internet of Vehicles(IoV)plays a crucial role in providing diversified services because of its powerful capability of collecting real-time information.Generally,collected information is transmitted to a centralized resourceintensive cloud platform for service implementation.Edge Computing(EC)that deploys physical resources near road-side units is involved in IoV to support real-time services for vehicular users.Additionally,many measures are adopted to optimize the performance of EC-enabled IoV,but they hardly help make dynamic decisions according to real-time requests.Artificial Intelligence(AI)is capable of enhancing the learning capacity of edge devices and thus assists in allocating resources dynamically.Although extensive research has employed AI to optimize EC performance,summaries with relative concepts or prospects are quite few.To address this gap,we conduct an exhaustive survey about utilizing AI in edge service optimization in IoV.Firstly,we establish the general condition and relative concepts about IoV,EC,and AI.Secondly,we review the edge service frameworks for IoV and explore the use of AI in edge server placement and service offloading.Finally,we discuss a number of open issues in optimizing edge services with AI. 展开更多
关键词 edge service internet of vehicles artificial intel igence
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Migration law of flax threshing materials in double channel air-and-screen separating cleaner 被引量:7
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作者 fei dai Xuefeng Song +3 位作者 Ruijie Shi Wuyun Zhao Wenjuan Guo Yang Zhang 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2021年第3期92-102,共11页
In order to further clarify and improve the working performance of separating cleaner for flax threshing materials,and study the migration law and characteristics of components of flax threshing materials during separ... In order to further clarify and improve the working performance of separating cleaner for flax threshing materials,and study the migration law and characteristics of components of flax threshing materials during separating and cleaning,in this paper,a gas-solid coupling simulation model was established on the separation cleaner for flax threshing materials and a numerical simulation was carried out on the separating and cleaning process.Simulation results showed that,the separating and cleaning effect of the components of flax threshing materials was good under the air-and-screen gas-solid coupling flow field.Meanwhile,the form distribution and the vector distribution of air volume and velocity of flax threshing materials in the air-and-screen devices were obtained.By referring to the migration trajectories of the flax threshing materials in the vibration sieve device,double channel residue collection device and dust absorber,the volume variation,motion trajectories and variation of migration velocity of the components of flax threshing materials over time in different regions were explored.Verification test results showed that,the content impurity rate of the separation cleaner for flax threshing materials was 2.06%,and loss rate in cleaning was 3.08%.Compared with simulation results,the verification test results were 1.23%and 0.42%higher,showing that the established discrete element model on the flax threshing materials and parameter setting were basically feasible.The verification test also verified the correctness of the simulation results of the separating and cleaning process of the flax threshing materials based on gas-solid coupling theory and the feasibility of the research method. 展开更多
关键词 flax threshing materials separation cleaner AIR-AND-SCREEN gas-solid coupling discrete element model numerical simulation
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