期刊文献+
共找到172,302篇文章
< 1 2 250 >
每页显示 20 50 100
A Review on Sources,Extractions and Analysis Methods of a Sustainable Biomaterial:Tannins 被引量:2
1
作者 Antonio Pizzi Marie-Pierre Laborie Zeki Candan 《Journal of Renewable Materials》 EI CAS 2024年第3期397-425,共29页
Condensed and hydrolysable tannins are non-toxic natural polyphenols that are a commercial commodity industrialized for tanning hides to obtain leather and for a growing number of other industrial applications mainly ... Condensed and hydrolysable tannins are non-toxic natural polyphenols that are a commercial commodity industrialized for tanning hides to obtain leather and for a growing number of other industrial applications mainly to substitute petroleum-based products.They are a definite class of sustainable materials of the forestry industry.They have been in operation for hundreds of years to manufacture leather and now for a growing number of applications in a variety of other industries,such as wood adhesives,metal coating,pharmaceutical/medical applications and several others.This review presents the main sources,either already or potentially commercial of this forestry by-materials,their industrial and laboratory extraction systems,their systems of analysis with their advantages and drawbacks,be these methods so simple to even appear primitive but nonetheless of proven effectiveness,or very modern and instrumental.It constitutes a basic but essential summary of what is necessary to know of these sustainable materials.In doing so,the review highlights some of the main challenges that remain to be addressed to deliver the quality and economics of tannin supply necessary to fulfill the industrial production requirements for some materials-based uses. 展开更多
关键词 TANNINS FLAVONOIDS SOURCES extraction methods analysis methods
下载PDF
Automatic Extraction Method of 3D Feature Guidelines for Complex Cultural Relic Surfaces Based on Point Cloud 被引量:1
2
作者 GENG Yuxin ZHONG Ruofei +1 位作者 HUANG Yuqin SUN Haili 《Journal of Geodesy and Geoinformation Science》 CSCD 2024年第1期16-41,共26页
Cultural relics line graphic serves as a crucial form of traditional artifact information documentation,which is a simple and intuitive product with low cost of displaying compared with 3D models.Dimensionality reduct... Cultural relics line graphic serves as a crucial form of traditional artifact information documentation,which is a simple and intuitive product with low cost of displaying compared with 3D models.Dimensionality reduction is undoubtedly necessary for line drawings.However,most existing methods for artifact drawing rely on the principles of orthographic projection that always cannot avoid angle occlusion and data overlapping while the surface of cultural relics is complex.Therefore,conformal mapping was introduced as a dimensionality reduction way to compensate for the limitation of orthographic projection.Based on the given criteria for assessing surface complexity,this paper proposed a three-dimensional feature guideline extraction method for complex cultural relic surfaces.A 2D and 3D combined factor that measured the importance of points on describing surface features,vertex weight,was designed.Then the selection threshold for feature guideline extraction was determined based on the differences between vertex weight and shape index distributions.The feasibility and stability were verified through experiments conducted on real cultural relic surface data.Results demonstrated the ability of the method to address the challenges associated with the automatic generation of line drawings for complex surfaces.The extraction method and the obtained results will be useful for line graphic drawing,displaying and propaganda of cultural relics. 展开更多
关键词 point cloud conformal parameterization vertex weight surface mesh cultural relics feature extraction
下载PDF
Preferentially selective extraction of lithium from spent LiCoO_(2)cathodes by medium-temperature carbon reduction roasting 被引量:1
3
作者 Daixiang Wei Wei Wang +6 位作者 Longjin Jiang Zhidong Chang Hualei Zhou Bin Dong Dekun Gao Minghui Zhang Chaofan Wu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第2期315-322,共8页
Lithium recovery from spent lithium-ion batteries(LIBs)have attracted extensive attention due to the skyrocketing price of lithium.The medium-temperature carbon reduction roasting was proposed to preferential selectiv... Lithium recovery from spent lithium-ion batteries(LIBs)have attracted extensive attention due to the skyrocketing price of lithium.The medium-temperature carbon reduction roasting was proposed to preferential selective extraction of lithium from spent Li-CoO_(2)(LCO)cathodes to overcome the incomplete recovery and loss of lithium during the recycling process.The LCO layered structure was destroyed and lithium was completely converted into water-soluble Li2CO_(3)under a suitable temperature to control the reduced state of the cobalt oxide.The Co metal agglomerates generated during medium-temperature carbon reduction roasting were broken by wet grinding and ultrasonic crushing to release the entrained lithium.The results showed that 99.10%of the whole lithium could be recovered as Li2CO_(3)with a purity of 99.55%.This work provided a new perspective on the preferentially selective extraction of lithium from spent lithium batteries. 展开更多
关键词 spent LiCoO_(2)cathodes medium-temperature carbon reduction lithium extraction priority crystal transformation macro-scopic transport resistance
下载PDF
Effects of conductive agent type on lithium extraction from salt lake brine with LiFePO_(4) electrodes
4
作者 Zhen Zhang Pan Luo +7 位作者 Yan Zhang Yuhan Wang Li Liao Bo Yu Mingshan Wang Junchen Chen Bingshu Guo Xing Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第4期678-687,共10页
Electrochemical lithium extraction from salt lakes is an effective strategy for obtaining lithium at a low cost.Nevertheless,the elevated Mg:Li ratio and the presence of numerous coexisting ions in salt lake brines gi... Electrochemical lithium extraction from salt lakes is an effective strategy for obtaining lithium at a low cost.Nevertheless,the elevated Mg:Li ratio and the presence of numerous coexisting ions in salt lake brines give rise to challenges,such as prolonged lithium extraction periods,diminished lithium extraction efficiency,and considerable environmental pollution.In this work,Li FePO4(LFP)served as the electrode material for electrochemical lithium extraction.The conductive network in the LFP electrode was optimized by adjusting the type of conductive agent.This approach resulted in high lithium extraction efficiency and extended cycle life.When the single conductive agent of acetylene black(AB)or multiwalled carbon nanotubes(MWCNTs)was replaced with the mixed conductive agent of AB/MWCNTs,the average diffusion coefficient of Li+in the electrode increased from 2.35×10^(-9)or 1.77×10^(-9)to 4.21×10^(-9)cm^(2)·s^(-1).At the current density of 20 mA·g^(-1),the average lithium extraction capacity per gram of LFP electrode increased from 30.36 mg with the single conductive agent(AB)to 35.62 mg with the mixed conductive agent(AB/MWCNTs).When the mixed conductive agent was used,the capacity retention of the electrode after 30 cycles reached 82.9%,which was considerably higher than the capacity retention of 65.8%obtained when the single AB was utilized.Meanwhile,the electrode with mixed conductive agent of AB/MWCNTs provided good cycling performance.When the conductive agent content decreased or the loading capacity increased,the electrode containing the mixed conductive agent continued to show excellent electrochemical performance.Furthermore,a self-designed,highly efficient,continuous lithium extraction device was constructed.The electrode utilizing the AB/MWCNT mixed conductive agent maintained excellent adsorption capacity and cycling performance in this device.This work provides a new perspective for the electrochemical extraction of lithium using LFP electrodes. 展开更多
关键词 salt lake brine lithium extraction electrochemical lithium extraction conductive agent extraction efficiency adsorption capacity
下载PDF
Influence of the Extraction Process on the Characteristics of Romanian Mountain Walnut Oil
5
作者 Anne-Gaëlle Gambert Sabina Niţu +6 位作者 Andra Tămaș Maria Laura Fanani Justine Dupré Clara Delepine Ludovic Chaveriat Patrick Martin Lucian Rusnac 《American Journal of Plant Sciences》 CAS 2024年第10期940-967,共28页
The objective of this work is to extract walnut oil using various processes in order to compare the influence on the nature of the components extracted, and thus identify the areas of potential use. We carried out the... The objective of this work is to extract walnut oil using various processes in order to compare the influence on the nature of the components extracted, and thus identify the areas of potential use. We carried out the extractions by mechanical process, thanks to a press in reduced model provided with a worm. We obtained cold extracted oil whose characteristics slightly diverge from extra virgin oil found in shops in Romania, but its composition is similar. We were also able to extract by chemical process using two methods, Folch and Soxhlet. Commercially available table walnut oils are only cold extracted to avoid the presence of solvents. Those are difficult to remove and strongly oxidize the oil. Currently, consumers appreciate walnut oil for its taste and nutritional qualities. In nutrition, this oil is put forward for its composition rich in polyunsaturated fatty acids, which are needed for human body. Food supplements made from walnut oil are available today. For the moment, this is the only use of walnut oil. Indeed, there are some studies on other fields of application, but they remain in the field of research and nothing has yet been commercialized. In this present study, we compared the chemical and physical properties of cold-extracted oil with the solvent extraction of walnut kernel originating from the mountain region of Rumania. The cold extracted oil has a high content of polyunsaturated fatty acids (63%) and monounsaturated fatty acids (30%), a very low level of saturated fatty acid (7%) and no content of linolenic acid. The Soxhlet and Folch methods produced slightly different oils with increased amounts of minor components, which changes their characteristic. Even when solvent-extracted oils do not meet the standard criteria imposed by the Codex Alimentarius, they offer a possible use in the fields of food, cosmetics industries and biomedicine. 展开更多
关键词 Walnut Oil extraction COMPOSITION Romanian Mountain
下载PDF
Development of a Simple Extraction Method for Tetracycline Analogues from Bovine Milk
6
作者 Oscar Cordova Thien Le +4 位作者 Christopher Lambert Devin Brodie Stephany Ramirez Francis Sandoval Karno Ng 《Advances in Biological Chemistry》 CAS 2024年第4期111-120,共10页
Tetracycline and analogues are among the most used antibiotics in the dairy industry. Besides the therapeutic uses, tetracyclines are often incorporated into livestock feed as growth promoters. A considerable amount o... Tetracycline and analogues are among the most used antibiotics in the dairy industry. Besides the therapeutic uses, tetracyclines are often incorporated into livestock feed as growth promoters. A considerable amount of antibiotics is released unaltered through milk from dairy animals. The presence of antibiotic residues in milk and their subsequent consumption can lead to potential health impacts, including cancer, hypersensitivity reactions, and the development of antibiotic resistance. Thus, it is important to monitor residual levels of tetracyclines in milk. The purpose of this study is to develop a quick and simple method for simultaneously extracting five tetracycline analogues from bovine milk. Specifically, five tetracycline analogues: Chlortetracycline (CTC), demeclocycline (DEM), doxycycline (DC), minocycline (MC), and tetracycline (TC) were simultaneously extracted from milk using trifluoroacetic acid. Subsequently, the extracted analogues were separated by reverse-phase high-performance liquid chromatography (RP-HPLC) and detected at 355 nm using UV/Vis. Calibration curves for all five tetracycline analogues show excellent linearity (r2 value > 0.99). Percent recovery for MC, TC, DEM, CTC, and DC were: 31.88%, 96.91%, 151.29, 99.20%, and 85.58% respectively. The developed extraction method has good precision (RSD < 9.9% for 4 of the 5 analogues). The developed method with minimal sample preparation and pretreatment has the potential to serve as an initial screening test. 展开更多
关键词 ANTIBIOTICS TETRACYCLINES extraction MILK HPLC
下载PDF
A Joint Entity Relation Extraction Model Based on Relation Semantic Template Automatically Constructed
7
作者 Wei Liu Meijuan Yin +1 位作者 Jialong Zhang Lunchong Cui 《Computers, Materials & Continua》 SCIE EI 2024年第1期975-997,共23页
The joint entity relation extraction model which integrates the semantic information of relation is favored by relevant researchers because of its effectiveness in solving the overlapping of entities,and the method of... The joint entity relation extraction model which integrates the semantic information of relation is favored by relevant researchers because of its effectiveness in solving the overlapping of entities,and the method of defining the semantic template of relation manually is particularly prominent in the extraction effect because it can obtain the deep semantic information of relation.However,this method has some problems,such as relying on expert experience and poor portability.Inspired by the rule-based entity relation extraction method,this paper proposes a joint entity relation extraction model based on a relation semantic template automatically constructed,which is abbreviated as RSTAC.This model refines the extraction rules of relation semantic templates from relation corpus through dependency parsing and realizes the automatic construction of relation semantic templates.Based on the relation semantic template,the process of relation classification and triplet extraction is constrained,and finally,the entity relation triplet is obtained.The experimental results on the three major Chinese datasets of DuIE,SanWen,and FinRE showthat the RSTAC model successfully obtains rich deep semantics of relation,improves the extraction effect of entity relation triples,and the F1 scores are increased by an average of 0.96% compared with classical joint extraction models such as CasRel,TPLinker,and RFBFN. 展开更多
关键词 Natural language processing deep learning information extraction relation extraction relation semantic template
下载PDF
Development of Extraction and Detection Method for a Chemotherapeutic Drug with Phenytoin in Biological Samples
8
作者 Michael Arnot Nicolas Brice +3 位作者 Adan Garcia Victor Lomeli My Phuong Vu Karno Ng 《Advances in Biological Chemistry》 CAS 2024年第4期103-110,共8页
Dexamethasone is classified as a corticosteroid and is commonly used among cancer patients to decrease the amount of swelling around the tumor. Among patients with cancer, in particular brain tumors, seizures can beco... Dexamethasone is classified as a corticosteroid and is commonly used among cancer patients to decrease the amount of swelling around the tumor. Among patients with cancer, in particular brain tumors, seizures can become a daily routine in their everyday lives. To counteract the seizures, an antiepileptic drug such as phenytoin is administered to act as an anticonvulsant. Phenytoin and dexamethasone are frequently administrated concurrently to brain cancer patients. A previous study has shown that phenytoin serum concentration decreases when administrated concurrently with dexamethasone. Thus, it is important to monitor the concentration of these two drugs in biological samples to ensure that the proper dosages are administrated to the patients. This study aims to develop an effective extraction and detection method for dexamethasone and phenytoin. A reverse-phase high-performance liquid chromatography (HPLC) method with UV/Vis detection has been developed to separate phenytoin and dexamethasone at 219 nm and 241 nm respectively from urine samples. The mobile phase consists of a mixture of 0.01 M KH2PO4, acetonitrile, and methanol adjusted to pH 5.6 (48:32:20) and is pumped at a flow rate of 1.0 mL/min. Calibration curves were prepared for phenytoin and dexamethasone (r2 > 0.99). An efficient solid-phase extraction (SPE) method for the extraction of dexamethasone and phenytoin from urine samples was developed with the use of C-18 cartridges. The percent recovery for phenytoin and dexamethasone is 95.4% (RSD = 1.15%) and 81.1% (RSD = 3.56%) respectively. 展开更多
关键词 DEXAMETHASONE PHENYTOIN CANCER Drug Interaction Solid Phase extraction
下载PDF
Highly selective extraction of aromatics from aliphatics by using metal chloride-based ionic liquids
9
作者 Hui Yu Xiaojia Wu +4 位作者 Chuanqi Geng Xinyu Li Chencan Du Zhiyong Zhou Zhongqi Ren 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第1期222-229,共8页
The separation of aromatics from aliphatics is essential for achieving maximum exploitation of oil resources in the petrochemical industry.In this study,a series of metal chloride-based ionic liquids were prepared and... The separation of aromatics from aliphatics is essential for achieving maximum exploitation of oil resources in the petrochemical industry.In this study,a series of metal chloride-based ionic liquids were prepared and their performances in the separation of 1,2,3,4-tetrahydronaphthalene(tetralin)/dodecane and tetralin/decalin systems were studied.Among these ionic liquids,1-ethyl-3-methylimidazolium tetrachloroferrate([EMIM][FeCl_(4)])with the highest selectivity was used as the extractant.Density functional theory calculations showed that[EMIM][FeCl_(4)]interacted more strongly with tetralin than with dodecane and decalin.Energy decomposition analysis of[EMIM][FeCl_(4)]-tetralin indicated that electrostatics and dispersion played essential roles,and induction cannot be neglected.The van der Waals forces was a main effect in[EMIM][FeCl_(4)]-tetralin by independent gradient model analysis.The tetralin distribution coefficient and selectivity were 0.8 and 110,respectively,with 10%(mol)tetralin in the initial tetralin/dodecane system,and 0.67 and 19.5,respectively,with 10%(mol)tetralin in the initial tetralin/decalin system.The selectivity increased with decreasing alkyl chain length of the extractant.The influence of the extraction temperature,extractant dosage,and initial concentrations of the system components on the separation performance were studied.Recycling experiments showed that the regenerated[EMIM][FeCl_(4)]could be used repeatedly. 展开更多
关键词 Ionic liquid Aromatic hydrocarbon Aliphatic hydrocarbon extraction
下载PDF
Influence of extraction voltage on electron and ion behavior characteristics
10
作者 徐翱 甘娉娉 +1 位作者 石元杰 陈磊 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期553-559,共7页
The characteristics of the extracted ion current have a significant impact on the design and testing of ion source performance.In this paper,a 2D in space and 3D in velocity space particle in cell(2D3V PIC)method is u... The characteristics of the extracted ion current have a significant impact on the design and testing of ion source performance.In this paper,a 2D in space and 3D in velocity space particle in cell(2D3V PIC)method is utilized to simulate plasma motion and ion extraction characteristics under various initial plasma velocity distributions and extraction voltages in a Cartesian coordinate system.The plasma density is of the order of 10^(15)m^(-3)-10^(16)m^(-3)and the extraction voltage is of the order of 100 V-1000 V.The study investigates the impact of various extraction voltages on the velocity and density distributions of electrons and positive ions,and analyzes the influence of different initial plasma velocity distributions on the extraction current.The simulation results reveal that the main reason for the variation of extraction current is the spacecharge force formed by the relative aggregation of positive and negative net charges.This lays the foundation for a deeper understanding of extraction beam characteristics. 展开更多
关键词 extraction voltage PLASMA ion beam ion current
下载PDF
Feature extraction and learning approaches for cancellable biometrics:A survey
11
作者 Wencheng Yang Song Wang +2 位作者 Jiankun Hu Xiaohui Tao Yan Li 《CAAI Transactions on Intelligence Technology》 SCIE EI 2024年第1期4-25,共22页
Biometric recognition is a widely used technology for user authentication.In the application of this technology,biometric security and recognition accuracy are two important issues that should be considered.In terms o... Biometric recognition is a widely used technology for user authentication.In the application of this technology,biometric security and recognition accuracy are two important issues that should be considered.In terms of biometric security,cancellable biometrics is an effective technique for protecting biometric data.Regarding recognition accuracy,feature representation plays a significant role in the performance and reliability of cancellable biometric systems.How to design good feature representations for cancellable biometrics is a challenging topic that has attracted a great deal of attention from the computer vision community,especially from researchers of cancellable biometrics.Feature extraction and learning in cancellable biometrics is to find suitable feature representations with a view to achieving satisfactory recognition performance,while the privacy of biometric data is protected.This survey informs the progress,trend and challenges of feature extraction and learning for cancellable biometrics,thus shedding light on the latest developments and future research of this area. 展开更多
关键词 BIOMETRICS feature extraction
下载PDF
A bulk extraction method to determine the stable isotope ratios of iron,nickel,copper,zinc,and cadmium in seawater using multi-collector inductively coupled plasma mass spectrometry
12
作者 Zhan Shen Yuncong Ge +3 位作者 Jiahui Liu Wenkai Guan Wenfeng Hu Ruifeng Zhang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第7期125-137,共13页
The oceanic trace metals iron(Fe),nickel(Ni),copper(Cu),zinc(Zn),and cadmium(Cd)are crucial to marine phytoplankton growth and global carbon cycle,and the analysis of their stable isotopes can provide valuable insight... The oceanic trace metals iron(Fe),nickel(Ni),copper(Cu),zinc(Zn),and cadmium(Cd)are crucial to marine phytoplankton growth and global carbon cycle,and the analysis of their stable isotopes can provide valuable insights into their biogeochemical cycles within the ocean.However,the simultaneous isotopic analysis of multiple elements present in seawater is challenging because of their low concentrations,limited volumes of the test samples,and high salt matrix.In this study,we present the novel method developed for the simultaneous analysis of five isotope systems by 1 L seawater sample.In the developed method,the NOBIAS Chelate-PA1 resin was used to extract metals from seawater,the AG MP-1M anion-exchange resin to purify Cu,Fe,Zn,Cd,and the NOBIAS Chelate-PA1 resin to further extract Ni from the matrix elements.Finally,a multi-collector inductively coupled plasma mass spectroscope(MC-ICPMS)was employed for the isotopic measurements using a doublespike technique or sample-standard bracketing combined with internal normalization.This method exhibited low total procedural blanks(0.04 pg,0.04 pg,0.21 pg,0.15 pg,and 3 pg for Ni,Cu,Fe,Zn,and Cd,respectively)and high extraction efficiencies(100.5%±0.3%,100.2%±0.5%,97.8%±1.4%,99.9%±0.8%,and 100.1%±0.2%for Ni,Cu,Fe,Zn,and Cd,respectively).The external errors and external precisions of this method could be considered negligible.The proposed method was further tested on the seawater samples obtained from the whole vertical profile of a water column during the Chinese GEOTRACES GP09 cruise in the Northwest Pacific,and the results showed good agreement with previous related data.This innovative method will contribute to the advancement of isotope research and enhance our understanding of the marine biogeochemical cycling of Fe,Ni,Cu,Zn,and Cd. 展开更多
关键词 trace metal stable isotopes seawater bulk extraction
下载PDF
Extraction of Acoustic Normal Mode Depth Functions Using Range-Difference Method with Vertical Linear Array Data
13
作者 GAO Siyu LI Weilu +2 位作者 ZHANG Yinquan LI Xiaolei WANG Ning 《Journal of Ocean University of China》 SCIE CAS CSCD 2024年第4期871-882,共12页
Data-derived normal mode extraction is an effective method for extracting normal mode depth functions in the absence of marine environmental data.However,when the corresponding singular vectors become nonunique when t... Data-derived normal mode extraction is an effective method for extracting normal mode depth functions in the absence of marine environmental data.However,when the corresponding singular vectors become nonunique when two or more singular values obtained from the cross-spectral density matrix diagonalization are nearly equal,this results in unsatisfactory extraction outcomes for the normal mode depth functions.To address this issue,we introduced in this paper a range-difference singular value decomposition method for the extraction of normal mode depth functions.We performed the mode extraction by conducting singular value decomposition on the individual frequency components of the signal's cross-spectral density matrix.This was achieved by using pressure and its range-difference matrices constructed from vertical line array data.The proposed method was validated using simulated data.In addition,modes were successfully extracted from ambient noise. 展开更多
关键词 range difference depth function extraction normal mode
下载PDF
Insight into the experiment and extraction mechanism for separating carbazole from anthracene oil with quaternary ammonium-based deep eutectic solvents
14
作者 Xudong Zhang Yanhua Liu +4 位作者 Jun Shen Yugao Wang Gang Liu Yanxia Niu Qingtao Sheng 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第1期188-199,共12页
Carbazole is an irreplaceable basic organic chemical raw material and intermediate in industry.The separation of carbazole from anthracene oil by environmental benign solvents is important but still a challenge in che... Carbazole is an irreplaceable basic organic chemical raw material and intermediate in industry.The separation of carbazole from anthracene oil by environmental benign solvents is important but still a challenge in chemical engineering.Deep eutectic solvents (DESs) as a sustainable green separation solvent have been proposed for the separation of carbazole from model anthracene oil.In this research,three quaternary ammonium-based DESs were prepared using ethylene glycol (EG) as hydrogen bond donor and tetrabutylammonium chloride (TBAC),tetrabutylammonium bromide or choline chloride as hydrogen bond acceptors.To explore their extraction performance of carbazole,the conductor-like screening model for real solvents (COSMO-RS) model was used to predict the activity coefficient at infinite dilution (γ^(∞)) of carbazole in DESs,and the result indicated TBAC:EG (1:2) had the stronger extraction ability for carbazole due to the higher capacity at infinite dilution (C^(∞)) value.Then,the separation performance of these three DESs was evaluated by experiments,and the experimental results were in good agreement with the COSMO-RS prediction results.The TBAC:EG (1:2) was determined as the most promising solvent.Additionally,the extraction conditions of TBAC:EG (1:2) were optimized,and the extraction efficiency,distribution coefficient and selectivity of carbazole could reach up to 85.74%,30.18 and 66.10%,respectively.Moreover,the TBAC:EG (1:2) could be recycled by using environmentally friendly water as antisolvent.In addition,the separation performance of TBAC:EG (1:2) was also evaluated by real crude anthracene,the carbazole was obtained with purity and yield of 85.32%,60.27%,respectively.Lastly,the extraction mechanism was elucidated byσ-profiles and interaction energy analysis.Theoretical calculation results showed that the main driving force for the extraction process was the hydrogen bonding ((N–H...Cl) and van der Waals interactions (C–H...O and C–H...π),which corresponding to the blue and green isosurfaces in IGMH analysis.This work presented a novel method for separating carbazole from crude anthracene oil,and will provide an important reference for the separation of other high value-added products from coal tar. 展开更多
关键词 CARBAZOLE Model anthracene oil Deep eutectic solvents COSMO-RS extraction mechanism
下载PDF
Feature extraction for machine learning-based intrusion detection in IoT networks
15
作者 Mohanad Sarhan Siamak Layeghy +2 位作者 Nour Moustafa Marcus Gallagher Marius Portmann 《Digital Communications and Networks》 SCIE CSCD 2024年第1期205-216,共12页
A large number of network security breaches in IoT networks have demonstrated the unreliability of current Network Intrusion Detection Systems(NIDSs).Consequently,network interruptions and loss of sensitive data have ... A large number of network security breaches in IoT networks have demonstrated the unreliability of current Network Intrusion Detection Systems(NIDSs).Consequently,network interruptions and loss of sensitive data have occurred,which led to an active research area for improving NIDS technologies.In an analysis of related works,it was observed that most researchers aim to obtain better classification results by using a set of untried combinations of Feature Reduction(FR)and Machine Learning(ML)techniques on NIDS datasets.However,these datasets are different in feature sets,attack types,and network design.Therefore,this paper aims to discover whether these techniques can be generalised across various datasets.Six ML models are utilised:a Deep Feed Forward(DFF),Convolutional Neural Network(CNN),Recurrent Neural Network(RNN),Decision Tree(DT),Logistic Regression(LR),and Naive Bayes(NB).The accuracy of three Feature Extraction(FE)algorithms is detected;Principal Component Analysis(PCA),Auto-encoder(AE),and Linear Discriminant Analysis(LDA),are evaluated using three benchmark datasets:UNSW-NB15,ToN-IoT and CSE-CIC-IDS2018.Although PCA and AE algorithms have been widely used,the determination of their optimal number of extracted dimensions has been overlooked.The results indicate that no clear FE method or ML model can achieve the best scores for all datasets.The optimal number of extracted dimensions has been identified for each dataset,and LDA degrades the performance of the ML models on two datasets.The variance is used to analyse the extracted dimensions of LDA and PCA.Finally,this paper concludes that the choice of datasets significantly alters the performance of the applied techniques.We believe that a universal(benchmark)feature set is needed to facilitate further advancement and progress of research in this field. 展开更多
关键词 Feature extraction Machine learning Network intrusion detection system IOT
下载PDF
Extraction,chemical components,bioactive functions and adulteration identification of walnut oils:A review
16
作者 Yuan Gao Jia Hu +6 位作者 Xia Su Qi Li Caihong Su Yongling Li Gaiqin Ma Siyu Zhang Xiuzhu Yu 《Grain & Oil Science and Technology》 CAS 2024年第1期30-41,共12页
Walnut oil is a functional wood oil known to researchers that may potentially be a large source of Chinese edible oils.There are various extraction methods for walnut oil,including traditional(pressing,solvent-and enz... Walnut oil is a functional wood oil known to researchers that may potentially be a large source of Chinese edible oils.There are various extraction methods for walnut oil,including traditional(pressing,solvent-and enzymeassisted extraction)and novel methods(microwave,ultrasound,supercritical CO_(2),subcritical and other extraction technologies).Walnut oil is rich in nutrients,including phytosterols,tocopherols,polyphenols,squalene and minerals.It provides many health benefits,such as antioxidant,antitumor,anti-inflammatory,antidiabetic and lipid metabolism-related functions.In addition,the authentication of walnut oil has received much research attention.The present review provides detailed research on walnut oil extraction,composition,health benefits and adulteration identification methods.The path toward further walnut oil improvement in the context of the market value of walnut oil is also discussed. 展开更多
关键词 extraction technology Chemical composition Bioactive AUTHENTICATION
下载PDF
Ten-year observation of corneal densitometry and associated factors following small incision lenticule extraction
17
作者 Xiao-Song Han Fei Xia +4 位作者 Zhuo-Yi Chen Pei-Jun Yao Dong-Mei Yang Jing Zhao Xing-Tao Zhou 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第3期485-490,共6页
●AIM:To investigate the long-term changes of corneal densitometry(CD)and its contributing elements after small incision lenticule extraction(SMILE).●METHODS:Totally 31 eyes of 31 patients with mean spherical equival... ●AIM:To investigate the long-term changes of corneal densitometry(CD)and its contributing elements after small incision lenticule extraction(SMILE).●METHODS:Totally 31 eyes of 31 patients with mean spherical equivalent of-6.46±1.50 D and mean age 28.23±7.38y were enrolled.Full-scale examinations were conducted on all patients preoperatively and during followup.Visual acuity,manifest refraction,axial length,corneal thickness,corneal higher-order aberrations,and CD were evaluated.●RESULTS:All surgeries were completed successfully without complications or adverse events.Ten-year safety index was 1.17±0.20 and efficacy 1.04±0.28.CD value of 0–6 mm zones in central layer was statistically significantly lower 10y postoperatively,compared with preoperative values(0–2 mmΔ=-1.62,2–6 mmΔ=-1.24,P<0.01).There were no correlations between CD values and factors evaluated.●CONCLUSION:SMILE is a safe and efficient procedure for myopia on a long-term basis.CD values get lower 10y postoperatively,whose mechanism is to be further discussed. 展开更多
关键词 MYOPIA small incision lenticule extraction corneal densitometry
下载PDF
Online identification and extraction method of regional large-scale adjustable load-aggregation characteristics
18
作者 Siwei Li Liang Yue +1 位作者 Xiangyu Kong Chengshan Wang 《Global Energy Interconnection》 EI CSCD 2024年第3期313-323,共11页
This article introduces the concept of load aggregation,which involves a comprehensive analysis of loads to acquire their external characteristics for the purpose of modeling and analyzing power systems.The online ide... This article introduces the concept of load aggregation,which involves a comprehensive analysis of loads to acquire their external characteristics for the purpose of modeling and analyzing power systems.The online identification method is a computer-involved approach for data collection,processing,and system identification,commonly used for adaptive control and prediction.This paper proposes a method for dynamically aggregating large-scale adjustable loads to support high proportions of new energy integration,aiming to study the aggregation characteristics of regional large-scale adjustable loads using online identification techniques and feature extraction methods.The experiment selected 300 central air conditioners as the research subject and analyzed their regulation characteristics,economic efficiency,and comfort.The experimental results show that as the adjustment time of the air conditioner increases from 5 minutes to 35 minutes,the stable adjustment quantity during the adjustment period decreases from 28.46 to 3.57,indicating that air conditioning loads can be controlled over a long period and have better adjustment effects in the short term.Overall,the experimental results of this paper demonstrate that analyzing the aggregation characteristics of regional large-scale adjustable loads using online identification techniques and feature extraction algorithms is effective. 展开更多
关键词 Load aggregation Regional large-scale Online recognition Feature extraction method
下载PDF
Noise‐tolerant matched filter scheme supplemented with neural dynamics algorithm for sea island extraction
19
作者 Yiyu Chen Dongyang Fu +3 位作者 Difeng Wang Haoen Huang Yang Si Shangfeng Du 《CAAI Transactions on Intelligence Technology》 SCIE EI 2024年第4期996-1013,共18页
Achieving high‐precision extraction of sea islands from high‐resolution satellite remote sensing images is crucial for effective resource development and sustainable management.Unfortunately,achieving such accuracy ... Achieving high‐precision extraction of sea islands from high‐resolution satellite remote sensing images is crucial for effective resource development and sustainable management.Unfortunately,achieving such accuracy for sea island extraction presents significant challenges due to the presence of extensive background interference.A more widely applicable noise‐tolerant matched filter(NTMF)scheme is proposed for sea island extraction based on the MF scheme.The NTMF scheme effectively suppresses the background interference,leading to more accurate and robust sea island extraction.To further enhance the accuracy and robustness of the NTMF scheme,a neural dynamics algorithm is supplemented that adds an error integration feedback term to counter noise interference during internal computer operations in practical applications.Several comparative experiments were conducted on various remote sensing images of sea islands under different noisy working conditions to demonstrate the superiority of the proposed neural dynamics algorithm‐assisted NTMF scheme.These experiments confirm the ad-vantages of using the NTMF scheme for sea island extraction with the assistance of neural dynamics algorithm. 展开更多
关键词 edge detection image classification image recognition shape extraction
下载PDF
Network Configuration Entity Extraction Method Based on Transformer with Multi-Head Attention Mechanism
20
作者 Yang Yang Zhenying Qu +2 位作者 Zefan Yan Zhipeng Gao Ti Wang 《Computers, Materials & Continua》 SCIE EI 2024年第1期735-757,共23页
Nowadays,ensuring thequality of networkserviceshas become increasingly vital.Experts are turning toknowledge graph technology,with a significant emphasis on entity extraction in the identification of device configurat... Nowadays,ensuring thequality of networkserviceshas become increasingly vital.Experts are turning toknowledge graph technology,with a significant emphasis on entity extraction in the identification of device configurations.This research paper presents a novel entity extraction method that leverages a combination of active learning and attention mechanisms.Initially,an improved active learning approach is employed to select the most valuable unlabeled samples,which are subsequently submitted for expert labeling.This approach successfully addresses the problems of isolated points and sample redundancy within the network configuration sample set.Then the labeled samples are utilized to train the model for network configuration entity extraction.Furthermore,the multi-head self-attention of the transformer model is enhanced by introducing the Adaptive Weighting method based on the Laplace mixture distribution.This enhancement enables the transformer model to dynamically adapt its focus to words in various positions,displaying exceptional adaptability to abnormal data and further elevating the accuracy of the proposed model.Through comparisons with Random Sampling(RANDOM),Maximum Normalized Log-Probability(MNLP),Least Confidence(LC),Token Entrop(TE),and Entropy Query by Bagging(EQB),the proposed method,Entropy Query by Bagging and Maximum Influence Active Learning(EQBMIAL),achieves comparable performance with only 40% of the samples on both datasets,while other algorithms require 50% of the samples.Furthermore,the entity extraction algorithm with the Adaptive Weighted Multi-head Attention mechanism(AW-MHA)is compared with BILSTM-CRF,Mutil_Attention-Bilstm-Crf,Deep_Neural_Model_NER and BERT_Transformer,achieving precision rates of 75.98% and 98.32% on the two datasets,respectively.Statistical tests demonstrate the statistical significance and effectiveness of the proposed algorithms in this paper. 展开更多
关键词 Entity extraction network configuration knowledge graph active learning TRANSFORMER
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部