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Misclassification analysis of discriminant model
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作者 HUANG Li-wen 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2023年第2期180-191,共12页
This paper extends the criterion of the misclassification ratio of discriminant model and presents a new selection method of discriminant model.For selecting the discriminant model,this method establishes the rule of ... This paper extends the criterion of the misclassification ratio of discriminant model and presents a new selection method of discriminant model.For selecting the discriminant model,this method establishes the rule of misclassification degree ratio through misclassification ratio of the discriminant model and misclassification degree of the samples.To test the effect of this method,this work uses seven UCI data sets.Numerical experiments on these examples indicate that this method has certain rationality and has a better effect to select a discriminant model. 展开更多
关键词 discriminant model misclassi cation ratio misclassi cation degree
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SF-CNN: Deep Text Classification and Retrieval for Text Documents
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作者 R.Sarasu K.K.Thyagharajan N.R.Shanker 《Intelligent Automation & Soft Computing》 SCIE 2023年第2期1799-1813,共15页
Researchers and scientists need rapid access to text documents such as research papers,source code and dissertations.Many research documents are available on the Internet and need more time to retrieve exact documents... Researchers and scientists need rapid access to text documents such as research papers,source code and dissertations.Many research documents are available on the Internet and need more time to retrieve exact documents based on keywords.An efficient classification algorithm for retrieving documents based on keyword words is required.The traditional algorithm performs less because it never considers words’polysemy and the relationship between bag-of-words in keywords.To solve the above problem,Semantic Featured Convolution Neural Networks(SF-CNN)is proposed to obtain the key relationships among the searching keywords and build a structure for matching the words for retrieving correct text documents.The proposed SF-CNN is based on deep semantic-based bag-of-word representation for document retrieval.Traditional deep learning methods such as Convolutional Neural Network and Recurrent Neural Network never use semantic representation for bag-of-words.The experiment is performed with different document datasets for evaluating the performance of the proposed SF-CNN method.SF-CNN classifies the documents with an accuracy of 94%than the traditional algorithms. 展开更多
关键词 SEMaNTIC classification convolution neural networks semantic enhancement
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Efficient Object Detection and Classification Approach Using HTYOLOV4 and M^(2)RFO-CNN
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作者 V.Arulalan Dhananjay Kumar 《Computer Systems Science & Engineering》 SCIE EI 2023年第2期1703-1717,共15页
Object detection and classification are the trending research topics in thefield of computer vision because of their applications like visual surveillance.However,the vision-based objects detection and classification met... Object detection and classification are the trending research topics in thefield of computer vision because of their applications like visual surveillance.However,the vision-based objects detection and classification methods still suffer from detecting smaller objects and dense objects in the complex dynamic envir-onment with high accuracy and precision.The present paper proposes a novel enhanced method to detect and classify objects using Hyperbolic Tangent based You Only Look Once V4 with a Modified Manta-Ray Foraging Optimization-based Convolution Neural Network.Initially,in the pre-processing,the video data was converted into image sequences and Polynomial Adaptive Edge was applied to preserve the Algorithm method for image resizing and noise removal.The noiseless resized image sequences contrast was enhanced using Contrast Limited Adaptive Edge Preserving Algorithm.And,with the contrast-enhanced image sequences,the Hyperbolic Tangent based You Only Look Once V4 was trained for object detection.Additionally,to detect smaller objects with high accuracy,Grasp configuration was observed for every detected object.Finally,the Modified Manta-Ray Foraging Optimization-based Convolution Neural Network method was carried out for the detection and the classification of objects.Comparative experiments were conducted on various benchmark datasets and methods that showed improved accurate detection and classification results. 展开更多
关键词 Object detection hyperbolic tangent YOLO manta-ray foraging object classification
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Intelligent Risk-Identification Algorithm with Vision and 3D LiDAR Patterns at Damaged Buildings
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作者 Dahyeon Kim Jiyoung Min +2 位作者 Yongwoo Song Chulsu Kim Junho Ahn 《Intelligent Automation & Soft Computing》 SCIE 2023年第5期2315-2331,共17页
Existingfirefighting robots are focused on simple storage orfire sup-pression outside buildings rather than detection or recognition.Utilizing a large number of robots using expensive equipment is challenging.This study ... Existingfirefighting robots are focused on simple storage orfire sup-pression outside buildings rather than detection or recognition.Utilizing a large number of robots using expensive equipment is challenging.This study aims to increase the efficiency of search and rescue operations and the safety offirefigh-ters by detecting and identifying the disaster site by recognizing collapsed areas,obstacles,and rescuers on-site.A fusion algorithm combining a camera and three-dimension light detection and ranging(3D LiDAR)is proposed to detect and loca-lize the interiors of disaster sites.The algorithm detects obstacles by analyzingfloor segmentation and edge patterns using a mask regional convolutional neural network(mask R-CNN)features model based on the visual data collected from a parallelly connected camera and 3D LiDAR.People as objects are detected using you only look once version 4(YOLOv4)in the image data to localize persons requiring rescue.The point cloud data based on 3D LiDAR cluster the objects using the density-based spatial clustering of applications with noise(DBSCAN)clustering algorithm and estimate the distance to the actual object using the center point of the clustering result.The proposed artificial intelligence(AI)algorithm was verified based on individual sensors using a sensor-mounted robot in an actual building to detectfloor surfaces,atypical obstacles,and persons requiring rescue.Accordingly,the fused AI algorithm was comparatively verified. 展开更多
关键词 Three-dimension light detection and ranging VISION risk identification damaged building robot
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Structural modal parameter identifi cation and damage diagnosis based on Hilbert-Huang transform 被引量:12
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作者 Han Jianping Zheng Peijuan Wang Hongtao 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2014年第1期101-111,共11页
Traditional modal parameter identifi cation methods have many disadvantages,especially when used for processing nonlinear and non-stationary signals.In addition,they are usually not able to accurately identify the dam... Traditional modal parameter identifi cation methods have many disadvantages,especially when used for processing nonlinear and non-stationary signals.In addition,they are usually not able to accurately identify the damping ratio and damage.In this study,methods based on the Hilbert-Huang transform(HHT) are investigated for structural modal parameter identifi cation and damage diagnosis.First,mirror extension and prediction via a radial basis function(RBF) neural network are used to restrain the troublesome end-effect issue in empirical mode decomposition(EMD),which is a crucial part of HHT.Then,the approaches based on HHT combined with other techniques,such as the random decrement technique(RDT),natural excitation technique(NExT) and stochastic subspace identifi cation(SSI),are proposed to identify modal parameters of structures.Furthermore,a damage diagnosis method based on the HHT is also proposed.Time-varying instantaneous frequency and instantaneous energy are used to identify the damage evolution of the structure.The relative amplitude of the Hilbert marginal spectrum is used to identify the damage location of the structure.Finally,acceleration records at gauge points from shaking table testing of a 12-story reinforced concrete frame model are taken to validate the proposed approaches.The results show that the proposed approaches based on HHT for modal parameter identifi cation and damage diagnosis are reliable and practical. 展开更多
关键词 modal parameter identifi cation damage diagnosis Hilbert-Huang transform natural excitation technique stochastic subspace identifi cation random decrement method shaking table test
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Prognosis-related classifi cation and dynamic monitoring of immune status in patients with sepsis:A prospective observational study 被引量:16
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作者 Jun Yin Yao Chen +10 位作者 Jun-ling Huang Lei Yan Zhong-shu Kuang Ming-ming Xue Si Sun Hao Xiang Yan-yan Hu Zhi-min Dong Chao-yang Tong Chun-xue Bai Zhen-ju Song 《World Journal of Emergency Medicine》 SCIE CAS CSCD 2021年第3期185-191,共7页
BACKGROUND:The dynamic monitoring of immune status is crucial to the precise and individualized treatment of sepsis.In this study,we aim to introduce a model to describe and monitor the immune status of sepsis and to ... BACKGROUND:The dynamic monitoring of immune status is crucial to the precise and individualized treatment of sepsis.In this study,we aim to introduce a model to describe and monitor the immune status of sepsis and to explore its prognostic value.METHODS:A prospective observational study was carried out in Zhongshan Hospital,Fudan University,enrolling septic patients admitted between July 2016 and December 2018.Blood samples were collected at days 1 and 3.Serum cytokine levels(e.g.,tumor necrosis factor-α[TNF-α],interleukin-10[IL-10])and CD14+monocyte human leukocyte antigen-D-related(HLA-DR)expression were measured to serve as immune markers.Classifi cation of each immune status,namely systemic inflammatory response syndrome(SIRS),compensatory anti-inflammatory response syndrome(CARS),and mixed antagonistic response syndrome(MARS),was defined based on levels of immune markers.Changes of immune status were classifi ed into four groups which were stabilization(SB),deterioration(DT),remission(RM),and non-remission(NR).RESULTS:A total of 174 septic patients were enrolled including 50 non-survivors.Multivariate analysis discovered that IL-10 and HLA-DR expression levels at day 3 were independent prognostic factors.Patients with MARS had the highest mortality rate.Immune status of 46.1%patients changed from day 1 to day 3.Among four groups of immune status changes,DT had the highest mortality rate,followed by NR,RM,and SB with mortality rates of 64.7%,42.9%,and 11.2%,respectively.CONCLUSIONS:Severe immune disorder defi ned as MARS or deterioration of immune status defi ned as DT lead to the worst outcomes.The preliminary model of the classifi cation and dynamic monitoring of immune status based on immune markers has prognostic values and is worthy of further investigation. 展开更多
关键词 Infectious disease Immune dysfunction Immune status classifi cation CYTOKINE
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Modification of waste polyacrylonitrile fiber and its application as a filtrate reducer for drilling 被引量:3
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作者 Pei-Zhi Yu 《Petroleum Science》 SCIE CAS CSCD 2015年第2期325-329,共5页
Cationic polymer fluid loss additive (CPFL) was prepared by using the reaction of 2,3-epoxypropy- ltrimethyl ammonium chloride (EPTMAC) (as cationic reagent) with the amide group in the molecular structure of th... Cationic polymer fluid loss additive (CPFL) was prepared by using the reaction of 2,3-epoxypropy- ltrimethyl ammonium chloride (EPTMAC) (as cationic reagent) with the amide group in the molecular structure of the sodium salt of partially hydrolyzed polyacrylonitrile fibers (HPAN-Na). The chemical reaction was determined by studying the infrared absorption peaks of the materials and the products. The results proved that the cationic groups of EPTMAC were successfully grafted onto the HPAN molecular chain. The composition of the molecular chain of the product CPFL was determined by investigation and calculation of the elemental analysis results of the grafted HPAN and the final reaction product CPFL. The drilling fluid performance was evaluated, and the result showed that when the cation content was more than 0.27 mmol/g, the drilling fluid would have good resistance to fluid loss and to pollution from calcium chloride. 展开更多
关键词 acrylic fiber cationic agents Fluid lossagent. Spectroscopy
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Modification and aging precipitation behavior of hypereutectic AI-21wt.%Si alloy treated by P+Ce combination 被引量:2
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作者 Liu Pei Wang Aiqin Xie Jingpei 《China Foundry》 SCIE CAS 2014年第6期516-521,共6页
In the present study, the tested hypereutectic Al-21 wt.%Si alloys were prepared by modifying the melt using different proportions of P and Ce, and then applying T6 heat treatment. The modif ication effects and mechan... In the present study, the tested hypereutectic Al-21 wt.%Si alloys were prepared by modifying the melt using different proportions of P and Ce, and then applying T6 heat treatment. The modif ication effects and mechanism of P+Ce complex modif ier on the Si phase of hypereutectic Al-21 wt.%Si alloy were studied, and the aging precipitation behavior after modif ication was characterized by means of tensile strength measurement, OM, SEM and TEM analysis. The results show that the massive primary silicon phase particles are signif icantly ref ined after modif ication, while the needle-like eutectic silicon crystals become f ibrous and short. It was found that the mechanism of phosphorus modifi cation on the primary silicon can be attributed to heterogeneous nucleation of Al P, while the modification mechanism of Ce can be explained by adsorbing-twinning theory. In the aged microstructure of the modif ied hypereutectic Al-21 wt.%Si alloy, there existed some strengthening phases such as Al4Cu9, Al2 Cu, AlC u3, and Al57Mn12. The P+Ce complex modif ier not only affected the size of primary silicon and eutectic silicon, but also the aging behavior of alloys under the heat treatment process. When Al-21 wt.%Si alloy was modif ied using 0.08%wt.P + 0.6wt.% Ce, the aging precipitates were dispersed uniformly in the alloy, and its mechanical properties at room and elevated temperatures are optimized(Rm = 287.6 MPa at RT, Rm = 210 MPa at 300 ℃). 展开更多
关键词 combination modifi cation hypereutectic al-21wt.%Si alloy microstructure aging precipitation
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SYNTHESIS AND APPLICATION AS POLYMER ELECTROLYTE OF HOMO- AND COPOLYMERS OF 3-(2-CYANO ETHOXY)METHYL- AND 3-(METHOXY(TRIETHYLENOXY))METHYL-3'-METHYLOXETANE
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作者 冯增国 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2006年第5期503-513,共11页
Two oxetane-derived monomers, 3-(2-cyano-ethoxy)methyl- and 3-(methoxy-(triethylenoxy))methyl-3'- methyloxetane (COX and MTOX), were prepared from 3-hydroxymethyl-3'-methyloxetane. Their homo- and copolymeri... Two oxetane-derived monomers, 3-(2-cyano-ethoxy)methyl- and 3-(methoxy-(triethylenoxy))methyl-3'- methyloxetane (COX and MTOX), were prepared from 3-hydroxymethyl-3'-methyloxetane. Their homo- and copolymerization in solution were carried out by the cationic ring-opening polymerization with BF3 · Et2O and 1,4-butanediol as co-initiator. The molecular weight and molecular weight distribution were determined using GPC so as to reveal the competition and interchange between active chain end (ACE) and activated monomer (AM) mechanism in the process. The reactivity ratios of the two monomers were calculated according to Kelen-Tudos using ^1H-NMR analysis. The influence of functional side chains in the monomers on the copolymerization behaviors was discussed in virtue of the reactivity ratio data. When doped with lithium salt LiTFSI, the ion conductivity of the homopolymer of MTOX reached 10^-3.58 S/cm at 30℃ and 10^-2.73 S/cm at 80℃, respectively, showing its potential to be used as polymer electrolyte for lithium ion battery. 展开更多
关键词 Oxetane-derived monomer cationic ring-opening polymerization aM mechanism aCE mechanism Reactivity ratio Ion conductivity.
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Exploring the Cation Regulation Mechanism for Interfacial Water Involved in the Hydrogen Evolution Reaction by In Situ Raman Spectroscopy
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作者 Xueqiu You Dongao Zhang +4 位作者 Xia‑Guang Zhang Xiangyu Li Jing‑Hua Tian Yao‑Hui Wang Jian‑Feng Li 《Nano-Micro Letters》 SCIE EI CSCD 2024年第3期303-312,共10页
Interfacial water molecules are the most important participants in the hydrogen evolution reaction(HER).Hence,understanding the behavior and role that interfacial water plays will ultimately reveal the HER mechanism.U... Interfacial water molecules are the most important participants in the hydrogen evolution reaction(HER).Hence,understanding the behavior and role that interfacial water plays will ultimately reveal the HER mechanism.Unfortunately,investigating interfacial water is extremely challenging owing to the interference caused by bulk water molecules and complexity of the interfacial environment.Here,the behaviors of interfacial water in different cationic electrolytes on Pd surfaces were investigated by the electrochemistry,in situ core-shell nanostructure enhanced Raman spectroscopy and theoretical simulation techniques.Direct spectral evidence reveals a red shift in the frequency and a decrease in the intensity of interfacial water as the potential is shifted in the positively direction.When comparing the different cation electrolyte systems at a given potential,the frequency of the interfacial water peak increases in the specified order:Li+<Na^(+)<K^(+)<Ca^(2+)<Sr^(2+).The structure of interfacial water was optimized by adjusting the radius,valence,and concentration of cation to form the two-H down structure.This unique interfacial water structure will improve the charge transfer efficiency between the water and electrode further enhancing the HER performance.Therefore,local cation tuning strategies can be used to improve the HER performance by optimizing the interfacial water structure. 展开更多
关键词 In situ Raman Interfacial water Hydrogen evolution reaction cationS
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Cationic ordering transition in oxygen-redox layered oxide cathodes
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作者 Xinyan Li Ang Gao +10 位作者 Qinghua Zhang Hao Yu Pengxiang Ji Dongdong Xiao Xuefeng Wang Dong Su Xiaohui Rong Xiqian Yu Hong Li Yong-Sheng Hu Lin Gu 《Carbon Energy》 SCIE EI CAS CSCD 2024年第1期197-206,共10页
Understanding the structural origin of the competition between oxygen 2p and transition-metal 3d orbitals in oxygen-redox(OR)layered oxides is eminently desirable for exploring reversible and high-energy-density Li/Na... Understanding the structural origin of the competition between oxygen 2p and transition-metal 3d orbitals in oxygen-redox(OR)layered oxides is eminently desirable for exploring reversible and high-energy-density Li/Na-ion cathodes.Here,we reveal the correlation between cationic ordering transition and OR degradation in ribbon-ordered P3-Na_(0.6)Li_(0.2)Mn_(0.8)O_(2) via in situ structural analysis.Comparing two different voltage windows,the OR capacity can be improved approximately twofold when suppressing the in-plane cationic ordering transition.We find that the intralayer cationic migration is promoted by electrochemical reduction from Mn^(4+)to Jahn–Teller Mn^(3+)and the concomitant NaO_(6) stacking transformation from triangular prisms to octahedra,resulting in the loss of ribbon ordering and electrochemical decay.First-principles calculations reveal that Mn^(4+)/Mn^(3+)charge ordering and alignment of the degenerate eg orbital induce lattice-level collective Jahn–Teller distortion,which favors intralayer Mn-ion migration and thereby accelerates OR degradation.These findings unravel the relationship between in-plane cationic ordering and OR reversibility and highlight the importance of superstructure protection for the rational design of reversible OR-active layered oxide cathodes. 展开更多
关键词 cationic ordering layered oxide cathodes oxygen redox sodium-ion batteries
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Enabling an Inorganic-Rich Interface via Cationic Surfactant for High-Performance Lithium Metal Batteries
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作者 Zejun Sun Jinlin Yang +18 位作者 Hongfei Xu Chonglai Jiang Yuxiang Niu Xu Lian Yuan Liu Ruiqi Su Dayu Liu Yu Long Meng Wang Jingyu Mao Haotian Yang Baihua Cui Yukun Xiao Ganwen Chen Qi Zhang Zhenxiang Xing Jisheng Pan Gang Wu Wei Chen 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第8期1-17,共17页
An anion-rich electric double layer(EDL)region is favorable for fabricating an inorganic-rich solid-electrolyte interphase(SEI)towards stable lithium metal anode in ester electrolyte.Herein,cetyltrimethylammonium brom... An anion-rich electric double layer(EDL)region is favorable for fabricating an inorganic-rich solid-electrolyte interphase(SEI)towards stable lithium metal anode in ester electrolyte.Herein,cetyltrimethylammonium bromide(CTAB),a cationic surfactant,is adopted to draw more anions into EDL by ionic interactions that shield the repelling force on anions during lithium plating.In situ electrochemical surface-enhanced Raman spectroscopy results combined with molecular dynamics simulations validate the enrichment of NO_(3)^(−)/FSI−anions in the EDL region due to the positively charged CTA^(+).In-depth analysis of SEI structure by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry results confirmed the formation of the inorganic-rich SEI,which helps improve the kinetics of Li^(+)transfer,lower the charge transfer activation energy,and homogenize Li deposition.As a result,the Li||Li symmetric cell in the designed electrolyte displays a prolongated cycling time from 500 to 1300 h compared to that in the blank electrolyte at 0.5 mA cm^(-2) with a capacity of 1 mAh cm^(-2).Moreover,Li||LiFePO_(4) and Li||LiCoO_(2) with a high cathode mass loading of>10 mg cm^(-2) can be stably cycled over 180 cycles. 展开更多
关键词 cationic surfactant Lithium nitrate additive Solid-electrolyte interphase Electric double layer Lithium metal batteries
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Fabrication and Properties of a New Reactive Diluent for Cationic UV Curing
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作者 吴正森 黄笔武 +1 位作者 LIU Yuansheng SHEN Han 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2024年第4期1053-1060,共8页
The reactive diluent prepared by siloxane modified Trimethylene oxide can improve the performance of the UV curing system.Therefore,1,7-bis[(3-ethyl-3-methoxyoxacylobutane)propyl]octadecylosiloxane(BEMOPOMTS)was synth... The reactive diluent prepared by siloxane modified Trimethylene oxide can improve the performance of the UV curing system.Therefore,1,7-bis[(3-ethyl-3-methoxyoxacylobutane)propyl]octadecylosiloxane(BEMOPOMTS)was synthesized from diethyl carbonate,trimethylopropanes,allyl bromide,and 1,1,3,3,5,5,7,7-octadecylosiloxane as the main raw materials.BEMOPOMTS can be used as reactive diluents in the field of cationic UV curing.It has good thermal stability,and the addition of BEMOPOMTS significantly improves the tensile strength and elongation at break of epoxy resin.Compared with the pure epoxy resin,adding 20%BEMOPOMTS increased the elastic modulus by 25%to 677 MPa. 展开更多
关键词 UV curing cation curing reactive diluent siloxane
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Disaster Monitoring of Satellite Image Processing Using Progressive Image Classification
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作者 Romany F.Mansour Eatedal Alabdulkreem 《Computer Systems Science & Engineering》 SCIE EI 2023年第2期1161-1169,共9页
The analysis of remote sensing image areas is needed for climate detec-tion and management,especially for monitoringflood disasters in critical environ-ments and applications.Satellites are mostly used to detect disast... The analysis of remote sensing image areas is needed for climate detec-tion and management,especially for monitoringflood disasters in critical environ-ments and applications.Satellites are mostly used to detect disasters on Earth,and they have advantages in capturing Earth images.Using the control technique,Earth images can be used to obtain detailed terrain information.Since the acquisi-tion of satellite and aerial imagery,this system has been able to detectfloods,and with increasing convenience,flood detection has become more desirable in the last few years.In this paper,a Big Data Set-based Progressive Image Classification Algorithm(PICA)system is introduced to implement an image processing tech-nique,detect disasters,and determine results with the help of the PICA,which allows disaster analysis to be extracted more effectively.The PICA is essential to overcoming strong shadows,for proper access to disaster characteristics to false positives by operators,and to false predictions that affect the impact of the disas-ter.The PICA creates tailoring and adjustments obtained from satellite images before training and post-disaster aerial image data patches.Two types of proposed PICA systems detect disasters faster and more accurately(95.6%). 展开更多
关键词 CLUSTERING SEGMENTaTION progressive image classification algorithm satellite image disaster detection
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A novel cationic collector for silicon removal from collophane using reverse flotation under acidic conditions 被引量:2
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作者 Zhongxian Wu Dongping Tao +2 位作者 Youjun Tao Man Jiang Patrick Zhang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第6期1038-1047,共10页
We analyzed a novel cationic collector using chemical plant byproducts,such as cetyltrimethylammonium bromide(CTAB)and dibutyl phthalate(DBP).Our aim is to establish a highly effective and economical process for the r... We analyzed a novel cationic collector using chemical plant byproducts,such as cetyltrimethylammonium bromide(CTAB)and dibutyl phthalate(DBP).Our aim is to establish a highly effective and economical process for the removal of quartz from collophane.A microflotation test with a 25 mg·L^(−1)collector at pH value of 6-10 demonstrates a considerable difference in the floatability of pure quartz and fluorapatite.Flotation tests for a collophane sample subjected to the first reverse flotation for magnesium removal demonstrates that a rough flotation process(using a 0.4 kg·t−1 new collector at pH=6)results in a collophane concentrate with 29.33wt%P_(2)O_(5)grade and 12.66wt%SiO2 at a 79.69wt%P_(2)O_(5)recovery,providing desirable results.Mechanism studies using Fourier transform infrared spectroscopy,zeta potential,and contact angle measurements show that the adsorption capacity of the new collector for quartz is higher than that for fluorapatite.The synergistic effect of DBP increases the difference in hydrophobicity between quartz and fluorapatite.The maximum defoaming rate of the novel cationic collector reaches 142.8 mL·min−1.This is considerably higher than that of a conventional cationic collector. 展开更多
关键词 cationic collector collophane DEFOaMING QUaRTZ reverse flotation
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Third-Order Nonlinear Optical Responses of Bis(15-crown-5)-stilbenes Binding to One-or Two-Alkali Metal Cation(Li^(+),Na^(+)and K^(+))
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作者 Hai-Ling Yu Tong Zhang +2 位作者 Tian-Liang Ma Bo Hong Zhi-Qiang Cheng 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2023年第5期601-612,I0002,共13页
Bis(15-crown-5)-stilbenes containing crown ether parts have been widely used in a variety of chemical applications,such as cation detectors,because of their ability to selectively bind to alkali metal cations,Bis(15-c... Bis(15-crown-5)-stilbenes containing crown ether parts have been widely used in a variety of chemical applications,such as cation detectors,because of their ability to selectively bind to alkali metal cations,Bis(15-crown-5)-stilbenes and its derivatives with complexation of one-or two-alkali metal cation(Li^(+),Na^(+)and K^(+))have been theoretically investigat-ed by quantum chemistry methods.The coordination of alkali cations results in partial shrinkage of crown ethers,which directly affected natural distribution analysis charges and molecular orbital energy levels.The number of alkali metal ions has significant effects on absorption spectra and mean second hyperpolarizability.When one alkali metal ion was added to the anticonformer of bis(15-crown-5)-stilbene,the absorption spectra were obvious-ly redshifted and the mean second hyperpolarizability values were slightly increased;while two alkali metal ions were added to bis(15-crown-5)-stilbene,the absorption spectra were ob-viously blue shifted and the mean second hyperpolarizability values decreased.On the other hand,as the radius of the alkali ions increased,the mean second hyperpolarizability values of the compounds increased gradually.It is indicated that the mean second hyperpolarizability value is sensitive to the number and radius of the alkali metal cations,thus the third order nonlinear optical response can be used as a signal to detect the number and type of alkali met-al ions. 展开更多
关键词 Bis(crown)-stilbene cation detector Metal cation Quantum chemistry Sec-ond hyperpolarizability
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One-step crosslinking preparation of tannic acid particles for the adsorption and separation of cationic dyes
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作者 Yujia Cui Zhiqiang Tan +2 位作者 Yanan Wang Shuxian Shi Xiaonong Chen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第5期309-318,共10页
In this study,a new tannic acid adsorbent(ethylene glycol diglycidyl ether crosslinked tannic acid,TAEGDE)for adsorptive removal of dyes from water was prepared using EGDE as a cross-linking agent.The resultant TA-EGD... In this study,a new tannic acid adsorbent(ethylene glycol diglycidyl ether crosslinked tannic acid,TAEGDE)for adsorptive removal of dyes from water was prepared using EGDE as a cross-linking agent.The resultant TA-EGDE was in particulate form with rough surface morphology and a diameter ranging from 10 to 30μm.The adsorption performance of the TA-EGDE was evaluated in a flow-through mode using water samples contaminated with methylene blue(MB)and two-component mixed dyes,respectively.The TA-EGDE provided adsorption capacity up to 721.8 mg·g^(-1)at 65°C for MB.It showed a high removal efficiency(99%)of MB(50 mg·L^(-1))from the water sample and could recovery 90%of the adsorbed MB by eluting with acidic ethanol aqueous solution.The excellent adsorption of MB and neutral red on the TA-EGDE may be the result of the synergy of electrostatic interaction andπ-πinteraction.Furthermore,the TA-EGDE could separate dyes from water samples contaminated with twocomponent mixed dyes with a separation coefficient ranging from 1.8 to 36.5.The anionic TA-EGDE would be an effective adsorbent to remove and recycle dyes from the contaminated water. 展开更多
关键词 Tannic acid Water treatment cationic dyes aDSORPTION Recovery Dyes separation
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Divalent nitrogen-rich cationic salts with great gas production capacities
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作者 Hao Gu Cheng-chuang Li +3 位作者 Chang-hao Dai Dong-xu Chen Hong-wei Yang Guang-bin Cheng 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第4期54-68,共15页
Monocyclic nitrogen-rich 3-(aminomethyl)-4,5-diamine-1,2,4-triazole(1)and fused cyclic 3,7-diamine-6-(aminomethyl)-[1,2,4]triazolo[4,3-b][1,2,4]triazole(9)were synthesized through the convenient cyclization reaction f... Monocyclic nitrogen-rich 3-(aminomethyl)-4,5-diamine-1,2,4-triazole(1)and fused cyclic 3,7-diamine-6-(aminomethyl)-[1,2,4]triazolo[4,3-b][1,2,4]triazole(9)were synthesized through the convenient cyclization reaction from the readily available reactant.Their energetic salts with high nitrogen content were proved to be rare examples of divalent monocyclic/fused cyclic cationic salts according to the single crystal analyses.The structure of intermediate B was also identified and verified by its trivalent cation crystal 17.5H_2O indirectly.Energetic compounds 2-8 and 10-17 were fully characterized by NMR spectroscopy,infrared spectroscopy,differential scanning calorimetry,elemental analysis.These energetic salts exhibit good thermal stability with decomposition temperatures ranged from 182℃to 245℃.The sensitivity of compounds 2,6,10 and 14 is similar or superior to that of RDX while the others were much more insensitive to mechanical stimulate.Furthermore,detonation velocity of 10(8843 m/s)surpass that of RDX(D=8795 m/s).Considering the high gas production volume(≥808 L/kg)of 2,4,10and 12,constant-volume combustion experiments were conduct to evaluate their gas production capacities specifically.These compounds possess much higher maximum gas-production pressures(P_(max):7.88-10.08 MPa)than the commonly used reagent guanidine nitrate(GN:P_(max)=4.20 MPa),which indicate their strong gas production capacity. 展开更多
关键词 Fused cyclic compound TRIaZOLE Divalent cation Gas production Energetic materials
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Styrene epoxidation catalyzed by polyoxometalate/quaternary ammonium phase transfer catalysts: The effect of cation size and catalyst deactivation mechanism
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作者 Qiongna Xiao Yuyan Jiang +3 位作者 Weiqiang Yuan Jingjing Chen Haohong Li Huidong Zheng 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第3期192-201,共10页
Catalytic epoxidation of alkenes is an important type of organic reaction in chemical industry,and the deep insight into catalyst deactivation will help to develop new epoxidation process.In this work,series of quater... Catalytic epoxidation of alkenes is an important type of organic reaction in chemical industry,and the deep insight into catalyst deactivation will help to develop new epoxidation process.In this work,series of quaternary ammoniums bearing different cationic sizes,i.e.MTOA+(methyltrioctylammonium,[(C_(8)H_(17))_(3)CH_(3)N]+),HTMA+(hexadecyltrimethylammonium,[(C_(16)H_(33))(CH_(3))_(3)N]+) and DMDOA+(dimethyldioctadecylammonium,[(C_(18)H_(37))_(2)(CH_(3))_(2)N]+) were incorporated with polyoxometalate (POM) anions to prepare phase transfer catalysts (PTCs),which were used in the styrene epoxidations.Among them,(MTOA)_(3)PW_(4)O_(24)exhibits the best catalytic performance judged from the highest styrene conversion rate(52%) and styrene oxide selectivity (93%),during which the styrene epoxidation conditions were optimized.Meanwhile,the deactivation mechanism of this kind of PTCs was proposed firstly,i.e.in the case of low H_(2)O_(2) content,the oxidant can only be used in the styrene epoxidation,in which the catalyst can transform into stable Keggin-type POM.But when the content of H_(2)O_(2) is higher,the excess H_(2)O_(2) can reactivate the Keggin-type POM into active (PW_(4)O_(24))_(3)-anions,which can trigger the ring-opening polymerization of styrene oxide.Consequently,the catalyst is deactivated by adhered poly(styrene oxide)irreversibly,which was determined by NMR spectra.In this situation,the active moiety{PO_(4)[WO(O_(2))_(2)]_(4)}_(3)-in phase-transfer catalytic system can break into some unidentified species with low W/P ratio with the presence of epoxides.This work will be beneficial for the design of new PTCs in alkene epoxidation in fine chemical industry. 展开更多
关键词 Phosphotungstic acid phase-transfer CaTaLYST Styrene epoxidation Catalyst deactivation mechanism cation size effect
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Addressing cation mixing in layered structured cathodes for lithium-ion batteries:A critical review
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作者 Jingxi Li Gemeng Liang +4 位作者 Wei Zheng Shilin Zhang Kenneth Davey Wei Kong Pang Zaiping Guo 《Nano Materials Science》 EI CAS CSCD 2023年第4期404-420,共17页
High-performance lithium-ion batteries(LIB)are important in powering emerging technologies.Cathodes are regarded as the bottleneck of increasing battery energy density,among which layered oxides are the most promising... High-performance lithium-ion batteries(LIB)are important in powering emerging technologies.Cathodes are regarded as the bottleneck of increasing battery energy density,among which layered oxides are the most promising candidates for LIB.However,a limitation with layered oxides cathodes is the transition metal and Li site mixing,which significantly impacts battery capacity and cycling stability.Despite recent research on Li/Ni mixing,there is a lack of comprehensive understanding of the origin of cation mixing between the transition metal and Li;therefore,practical means to address it.Here,a critical review of cation mixing in layered cathodes has been provided,emphasising the understanding of cation mixing mechanisms and their impact on cathode material design.We list and compare advanced characterisation techniques to detect cation mixing in the material structure;examine methods to regulate the degree of cation mixing in layered oxides to boost battery capacity and cycling performance,and critically assess how these can be applied practically.An appraisal of future research directions,including superexchange interaction to stabilise structures and boost capacity retention has also been concluded.Findings will be of immediate benefit in the design of layered cathodes for high-performance rechargeable LIB and,therefore,of interest to researchers and manufacturers. 展开更多
关键词 cation mixing Layered oxide cathodes Lithium-ion batteries Electrochemical performance
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