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RFFsNet-SEI:a multidimensional balanced-RFFs deep neural network framework for specific emitter identification

Journal of Systems Engineering and Electronics 2024年第3期35卷 558-574,F0002页

作者： FAN Rong si Chengke HAN Yi WAN Qun School of Information and Communication Engineering University of Electronic Science and Technology of ChinaChengdu 611731China Institute of Electronic and Electrical Engineering Civil Aviation Flight University of ChinaGuanghan 618307China

Existing specific emitter identification(SEI)methods based on hand-crafted features have drawbacks of losing feature information and involving multiple processing stages,which reduce the identification accuracy of emitters and complicate the procedures of *** this paper,we propose a deep SEI approach via multidimensional feature extraction for radio frequency fingerprints(RFFs),namely,***,we extract multidimensional physical RFFs from the received signal by virtue of variational mode decomposition(VMD)and Hilbert transform(HT).The physical RFFs and I-Q data are formed into the balanced-RFFs,which are then used to train *** introducing model-aided RFFs into neural network,the hybrid-driven scheme including physical features and I-Q data is *** improves physical interpretability of ***,since RFFsNet-SEI identifies individual of emitters from received raw data in end-to-end,it accelerates SEI implementation and simplifies procedures of ***,as the temporal features and spectral features of the received signal are both extracted by RFFsNet-SEI,identification accuracy is ***,we compare RFFsNet-SEI with the counterparts in terms of identification accuracy,computational complexity,and prediction *** results illustrate that the proposed method outperforms the counterparts on the basis of simulation dataset and real dataset collected in the anechoic chamber.

关键词： specific emitter identification(SEI) deep learning(DL) radio frequency fingerprint(RFF) multidimensional feature extraction(MFE) variational mode decomposition(VMD)

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Time-lagged Effects of the Spring Atmospheric Heat Source over the Tibetan Plateau on Summer Precipitation in Northeast China during 1961–2020:Role of Soil Moisture

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Advances in Atmospheric Sciences 2024年第8期41卷 1527-1538页

作者： Yizhe HAN Dabang jiaNG Dong si Yaoming MA Weiqiang MA Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China State Key Laboratory of Tibetan Plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China College of Atmospheric Sciences Lanzhou UniversityLanzhou 730000China National Observation and Research Station for Qomolongma Special Atmospheric Processes and Environmental Changes Dingri 858200China Kathmandu Center of Research and Education Chinese Academy of SciencesBeijing 100101China China-Pakistan Joint Research Center on Earth Sciences Chinese Academy of SciencesIslamabad 45320Pakistan

The spring atmospheric heat source(AHS)over the Tibetan Plateau(TP)has been suggested to affect the Asian summer monsoon and summer precipitation over South ***,its influence on the summer precipitation in Northeast China(NEC)remains *** connection between spring TP AHS and subsequent summer precipitation over NEC from 1961 to 2020 is analyzed in this *** illustrate that stronger spring TP AHS can enhance subsequent summer NEC precipitation,and higher soil moisture in the Yellow River Valley-North China region(YRVNC)acts as a *** spring,the strong TP AHS could strengthen the transportation of water vapor to East China and lead to excessive rainfall in the ***,soil moisture increases,which regulates local thermal conditions by decreasing local surface skin temperature and sensible *** to the memory of soil moisture,the lower spring sensible heat over the YRVNC can last until mid-summer,decrease the land–sea thermal contrast,and weaken the southerly winds over the East Asia–western Pacific region and convective activities over the South China Sea and tropical western *** modulates the East Asia–Pacific teleconnection pattern,which leads to a cyclonic anomaly and excessive summer precipitation over NEC.

关键词： Tibetan Plateau atmospheric heat source Northeast China summer precipitation soil moisture

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Quantification of perfluorinated compounds in atmospheric particulate shows potential connection with environmental event

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Journal of Environmental Sciences 2024年第2期136卷 237-247页

作者： Hua Tang Ying Wang Shengling si Hongli Li David Da Yong Chen National Institute of Metrology 18 BeisanhuandongluChaoyang DistrictBeijing 100029China School of Chemistry and Materials Science Nanjing Normal UniversityNanjing 210023China si Chuan Zhong Ce Biao Wu Technology Co.Ltd. Sichuan 610052China Department of Chemistry University of British ColumbiaVancouver V6T 1Z1BCCanada

A method of quantification of perfluorinated compounds(PFCs)from atmospheric particulate matter(APM)is described.A single step pretreatment method,selective pressurized liquid extraction(SPLE),was developed to reduce the high matrix background and avoid contamination from commonly used multiple sample pretreatment *** effective sorbent was selected to purify the PFCs during SPLE,followed by liquid chromatography-tandem mass spectrometry(LC–MS/MS),for quantification of *** affecting the SPLE efficiency,including temperature,static extraction time,and number of extraction cycles used,were *** optimum conditions were found to be 120℃,10 min,and 3 cycles,***-MS/MS method was developed to obtain the optimal sensitivity specific to *** method detection limits(MDLs)were 0.006 to 0.48 ng/g for the PFCs studied and the linear response range was from 0.1 to 100 ng/*** ensure accurate values were obtained,each step of the experiment was evaluated and controlled to prevent *** optimized method was tested by performing spiking experiments in natural particulate matter matrices and good rates of recovery and reproducibility were obtained for all target ***,the method was successfully used to measure 16 PFCs in the APM samples collected in Beijing over five years from 2015 to *** is observed that some PFCs follow the trend of total PFC changes,and can be attributed to the environment influencing events and policy enforcement,while others don't seem to change as much with time of the year or from year to year.

关键词： Selective pressurized liquid extraction Liquid chromatography-mass spectrometry Perfluorinated compounds Atmospheric particulate matter Pollution control

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Molecular dynamics study of hydrogen-induced cracking behavior of ferrite–pearlite gas transmission pipeline steel

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Journal of Iron and Steel Research(International) 2024年第2期31卷 488-500页

作者： Tao-long Xu si-han Guo Gong-zhen He Hao-yu Han Petroleum Engineering School Southwest Petroleum UniversityChengdu610500SichuanChina sichuan East Gas Transmission Sales Center of sinopec Natural Gas Branch Wuhan430074HubeiChina

Hydrogen embrittlement of pipelines depends on the hydrogen-induced cracking behavior of the pipeline steel *** on molecular dynamics analysis,the ferrite–cementite(α-Fe/Fe3C)lamellar atomic structure with the Bagaryatskii orientation relationship was established,and stepwise relaxation of the conjugate gradient energy minimization and constant-temperature and constant-pressure relaxation were performed under NPT(the isothermal–isobaric)*** mechanical property curves of theα-Fe/Fe3C models were obtained under different cementite terminal plane structures,and the evolution of the atomic structure was analyzed in *** addition,the influence of different hydrogen concentrations,different temperatures,different strain rates,changes in voids,and different micro-degrees of freedom on the deformation and failure mechanism of the model was investigated,aiming to provide a reliable way to explore the micro-mechanism of macro-cracking behavior of pipeline steel.

关键词： Ferrite-cementite lamellar structure Pipeline steel Failure mechanism Crack propagation Molecular dynamics

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Extreme value theory applied to the auroral electrojet indices

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Earth and Planetary Physics 2024年第2期8卷 375-381页

作者： si Chen Hong Yuan Yong Wei Guang Yang FengZheng Yu Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The study of extreme weather and space events has gained paramount importance in modern society owing to rapid advances in high *** and describing exceptional occurrences plays a crucial role in making decisive assessments of their potential impact on technical,economic,and social aspects in various *** research focuses on analyzing the hourly values of the auroral electrojet(AE)geomagnetic index from 1957 to 2019 by using the peak over threshold method in extreme value *** fitting the generalized Pareto distribution to extreme AE values,shape parameter indices were derived,revealing negative values that establish an upper bound for this time ***,it became evident that the AE values had reached a plateau,suggesting that extreme events exceeding the established upper limit are *** a result,although the need for diligent precautions to mitigate the consequences of such extreme events persists,surpassing the upper limit of AE values becomes increasingly *** is also possible to observe an aurora in the middle-and low-latitude regions during the maximum period of the AE index.

关键词： auroral electrojet indices extreme value theory extreme events

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Automated identification of steel weld defects,a convolutional neural network improved machine learning approach

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 294-308页

作者： Zhan SHU Ao WU Yuning si Hanlin DONG Dejiang WANG Yifan LI School of Mechanics and Engineering Science Shanghai UniversityShanghai 200444China School of Civil Engineering Shanghai Normal UniversityShanghai 201418China Shanghai PinlanData Technology Co. Ltd.Shanghai 200072China

This paper proposes a machine-learning-based methodology to automatically classify different types of steel weld defects,including lack of the fusion,porosity,slag inclusion,and the qualified(no defects)*** methodology solves the shortcomings of existing detection methods,such as expensive equipment,complicated operation and inability to detect internal *** study first collected percussed data from welded steel members with or without weld ***,three methods,the Mel frequency cepstral coefficients,short-time Fourier transform(STFT),and continuous wavelet transform were implemented and compared to explore the most appropriate features for classification of weld *** and convolutional neural network-enhanced algorithms were used to classify,the extracted ***,experiments were designed and performed to validate the proposed *** showed that STFT achieved higher accuracies(up to 96.63%on average)in the weld status *** convolutional neural network-enhanced support vector machine(SVM)outperformed six other algorithms with an average accuracy of 95.8%.In addition,random forest and SVM were efficient approaches with a balanced trade-off between the accuracies and the computational efforts.

关键词： steel weld machine learning convolutional neural network weld defect detection classification task percussion

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Grapevine-like high entropy oxide composites boost high-performance lithium sulfur batteries as bifunctional interlayers

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Green Energy & Environment 2024年第3期9卷 565-572页

作者： Huarong Fan Yubing si Yiming Zhang Fulong Zhu Xin Wang Yongzhu Fu College of Chemistry and Center of Green Catalysis Zhengzhou UniversityZhengzhou450001China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu611731China

Lithium-sulfur batteries(LSBs)with high energy densities have been demonstrated the potential for energy-intensive demand ***,their commercial applicability is hampered by hysteretic electrode reaction kinetics and the shuttle effect of lithium polysulfides(LiPSs).In this work,an interlayer consisting of high-entropy metal oxide(Cu_(0.7)Fe_(0.6)Mn_(0.4)Ni_(0.6)Sn_(0.5))O_(4) grown on carbon nanofibers(HEO/CNFs)is designed for *** CNFs with highly porous networks provide transport pathways for Li^(+) and e^(-),as well as a physical sieve effect to limit LiPSs *** particular,the grapevine-like HEO nanoparticles generate metal-sulfur bonds with LiPSs,efficiently anchoring active *** unique structure and function of the interlayer enable the LSBs with superior electrochemical performance,i.e.,the high specific capacity of 1381 mAh g^(-1) at 0.1 C and 561 mAh g^(-1) at 6 *** work presents a facile strategy for exploiting high-performance LSBs.

关键词： Electrospun carbon nanofibers Grapevine-like morphology Hierarchical physical sieve effect High-entropy induced chemisorption Lithium-sulfur battery

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Added value of ratio of cross diameters of the appendix in ultrasound diagnosis of acute appendicitis

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World Journal of Gastrointestinal Surgery 2024年第1期16卷 21-28页

作者： Feng-Wa Gu si-Ze Wu Department of Ultrasound The First Affiliated Hospital of Hainan Medical UniversityHaikou 570102Hainan ProvinceChina

BACKGROUND The maximum outer diameter(MOD)of the appendix is an essential parameter for diagnosing acute appendicitis,but there is space for improvement in ultrasound(US)diagnostic *** To investigate whether combining the ratio of the cross diameters(RATIO)of the appendix with MOD of the appendix can enhance the diagnostic performance of acute *** A retrospective study was conducted,and medical records of 233 patients with acute appendicitis and 112 patients with a normal appendix were *** MOD and RATIO of the appendix were calculated and tested for their diagnostic performance of acute appendicitis,both individually and in *** The RATIO for a normal appendix was 1.32±0.16,while for acute appendicitis it was 1.09±*** cut-off value for RATIO was determined to be≤*** area under the receiver operating characteristic curve(AUC)for diagnosing acute appendicitis using RATIO≤1.18 and MOD>6 mm was 0.870 and 0.652,*** was a significant difference in AUC between RATIO≤1.18 and MOD>6 mm(P6 mm with MOD>6 mm alone,the combination showed increased specificity,positive predictive value(PPV),and ***,the sensitivity and negative predictive value *** Combining RATIO of the appendix≤1.18 and MOD>6 mm can significantly improve the specificity,PPV,and AUC in the US diagnosis of acute appendicitis.

关键词： Acute appendicitis Diameter Ratio Diagnosis Ultrasound

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TCERG1L hypermethylation is a risk factor of diabetic retinopathy in Chinese children with type 1 diabetes

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International Journal of Ophthalmology(English edition) 2024年第3期17卷 537-544页

作者： Yu Qian Ying Xiao Qiu-Rong Lin Zhao-Yu Xiang Li-Pu Cui jia-Qi Sun si-Cong Li Xin-Ran Qin Hai-Dong Zou Chen-Hao Yang Pei-Yao Jin Department of Ophthalmology Shanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai First People’s HospitalShanghai 200080China Shanghai Eye Diseases Prevention&Treatment Center Shanghai Eye HospitalShanghai 200040China National Clinical Research Center for Eye Diseases Shanghai Clinical Research Center for Eye DiseasesShanghai Key Clinical SpecialtyShanghai Key Laboratory of Ocular Fundus DiseasesShanghai Engineering Center for Visual Science and PhotomedicineShanghai Engineering Center for Precise Diagnosis and Treatment of Eye DiseasesShanghai 200080China Department of Ophthalmology Children’s Hospital of Fudan UniversityShanghai 201102China

●AIM:To identify the differential methylation sites(DMS)and their according genes associated with diabetic retinopathy(DR)development in type 1 diabetes(T1DM)children.●METHODS:This study consists of two surveys.A total of 40 T1DM children was included in the first *** no participant has DR,retina thinning was used as a surrogate indicator for *** lowest 25%participants with the thinnest macular retinal thickness were included into the case group,and the others were *** DNA methylation status was assessed by the Illumina methylation 850K array BeadChip assay,and compared between the case and control *** DMS with a potential role in diabetes were *** second survey included 27 T1DM children,among which four had *** methylation patterns of the four DMS identified by 850K were compared between participants with and without DR by pyrosequencing.●RESULTS:In the first survey,the 850K array revealed 751 sites significantly and differentially methylated in the case group comparing with the controls(|Δβ|>0.1 and Adj.Psignificance of Adj.Psites were hypermethylated and 432 were hypomethylated in the case group relative to the *** revealed that the transcription elongation regulator 1 like(TCERG1L,cg07684215)gene was hypermethylated in the four T1DM children with DR(P=0.018),which was consistent with the result from the first *** methylation status of the other three DMS(cg26389052,cg25192647,and cg05413694)showed no difference(all P>0.05)between participants with and without DR.●CONCLUsiON:The hypermethylation of the TCERG1L gene is a risk factor for DR development in Chinese children with T1DM.

关键词： DNA methylation 850K array pyrosequencing diabetic retinopathy type 1 diabetes children

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An engineered Cas12i nuclease that is an efficient genome editing tool in animals and plants

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The Innovation 2024年第2期5卷 61-69页

作者： Zhiqiang Duan Yafeng Liang jialei Sun Hongjin Zheng Tong Lin Pengyu Luo Mengge Wang Ruiheng Liu Ying Chen Shuhua Guo Nannan jia Hongtao Xie Meili Zhou Minghui Xia Kaijun Zhao Shuhui Wang Na Liu Yongling jia Wei si Qitong Chen Yechun Hong Ruilin Tian jian-Kang Zhu Institute of Advanced Biotechnology and School of Medicine Southern University of Science and TechnologyShenzhen 518055China Bellagen Biotechnology Jinan 250000China Department of Medical Neuroscience School of MedicineKey University Laboratory of Metabolism and Health of GuangdongSouthern University of Science and TechnologyShenzhenGuangdong Province 518055China

The type V-I CRISPR-Cas system is becoming increasingly more attractive for genome ***,natural nucleases of this system often exhibit low efficiency,limiting their ***,we used structure-guided rational design and protein engineering to optimize an uncharacterized Cas12i nuclease,*** a result,we developed Cas-SF01,a Cas12i3 variant that exhibits significantly improved gene editing activity in mammalian ***-SF01 shows comparable or superior editing performance compared to SpCas9 and other Cas12 *** to natural Cas12i3,Cas-SF01 has an expanded PAM range and effectively recognizes NTTN and noncanonical NATN and TTVN *** addition,we identified an amino acid substitution,D876R,that markedly reduced the off-target effect while maintaining high on-target activity,leading to the development of CasSF01^(HiFi)(high-fidelity Cas-SF01).Finally,we show that Cas-SF01 has high gene editing activities in mice and *** results suggest that CasSF01 can serve as a robust gene editing platform with high efficiency and specificity for genome editing applications in various organisms.

关键词： system attractive rational

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