With Pueraria edulis from different habitats in Yunnan Province,Guangdong Province and Guangxi Zhuang autonomous region as materials,the medicinal materials of P.edulis were extracted by ethanol condensation reflux ex...With Pueraria edulis from different habitats in Yunnan Province,Guangdong Province and Guangxi Zhuang autonomous region as materials,the medicinal materials of P.edulis were extracted by ethanol condensation reflux extraction and ultrasound-assisted extraction,and the effects of different extraction methods the contents of total flavonoids in P.edulis from different areas were compared.The results showed that the best extraction time for P.edulis in Yunnan Province was 20 min,and that for Guangdong and Guangxi Zhuang Autonomous Region was 30 min.The yield of total flavonoids from P.edulis extracted by the condensation reflux extraction method was relatively better.The content of total flavonoids in P.edulis in Yunnan was the highest with an average content of 0.2557%,while the average content of total flavonoids in P.edulis in Guangdong was the lowest with an average content of 0.2108%.展开更多
[Objective] This study aimed to investigate the optimal technological condi- tions for ultrasouqd-assisted extraction of polysaccharides from Pinus tabulaeformis seed shells. [Melhod] Polysaccharides were extracted fr...[Objective] This study aimed to investigate the optimal technological condi- tions for ultrasouqd-assisted extraction of polysaccharides from Pinus tabulaeformis seed shells. [Melhod] Polysaccharides were extracted from P. tabulaeformis seed shells by ultrasound-assisted hot water extraction method and detected by phenol- concentrated sulfuric acid method. The effect of extraction temperature, extraction duration, solid-liquid ratio and extraction frequency on the extraction of polysaccha- rides was investigated using single-factor gradient experiment and the extraction conditions for polysaccharides from P. tabulaeformis seed shells were optimized us- ing L9(34) orthogonal design. [Result] The content of polysaccharides extracted twice at 60 ℃ for 25 min with solid-liquid ratio of 1:3.5 reached the maximum. The re- covery rate (n=-5) ranged from 97.71% to 100.67% and RSD was 1.56%, suggesting high stability. [Conclusion] A simple and efficient method for ultrasound-assisted ex- traction of polysaccharides from P. tabulaeformis seed shells was established in this study, which laid solid foundation for the development and utilization of abandoned pine nut shell resources.展开更多
[Objective] The paper was to optimize ultrasound-assisted extraction of proacyanidins from purple cabbage. [Method] The ultrasound-assisted extraction technology was used to study the extraction of proacyanidins from ...[Objective] The paper was to optimize ultrasound-assisted extraction of proacyanidins from purple cabbage. [Method] The ultrasound-assisted extraction technology was used to study the extraction of proacyanidins from purple cabbage. The effect of ethanol concentration, temperature, time, material-solution ratio and the power of ultrasound on extracting efficiency were studied by single-factor experiment. Based on this, L16(4%orthogonal test were conducted to determine the optimal condi- tion for extraction of proacyanidins from purple cabbage. [Result] The optimal condi- tion for extraction of proacyanidins from purple cabbage was as follows: ethanol concentration 50%, extraction temperature 50℃, extraction time 1 h, extraction power 540 W, material-liquid ratio 1:20. The extraction rate of procyanidins under this condition reached 104.8 mg/g. [Conclusion] The study provided a theoretical basis for scientific and reasonable utilization of procyanidins in purple cabbage.展开更多
Naturally occurring camptothecin(CPT) is an important source of chemotherapeutic agents.The extraction from Camptotheca acuminata is still the main approach to obtain CPT compared with total synthesis.In the present...Naturally occurring camptothecin(CPT) is an important source of chemotherapeutic agents.The extraction from Camptotheca acuminata is still the main approach to obtain CPT compared with total synthesis.In the present study,ultrasound-assisted extractions(UAE) of CPT from C.acuminata seeds with alkaline solutions were investigated and CPT yield were determined by High Performance Liquid Chromatography.The conditions of alkaline species and concentrations,extraction time,extraction temperature and ultrasonic power were optimized.Results show that both Na3PO4 and Na2CO3 solutions gain good extraction yields,whereas Na3PO4 solution has stronger basicity and need higher concentration than Na2CO3 solution does,thus aqueous Na2CO3 is more beneficial for the extraction.The optimal condition was ultrasonically extracted with 0.5% aqueous Na2CO3 at 50°C and ultrasonic power of 400 W for 60 min.Comparing with UAE with ethanol,the extraction with 0.5% Na2CO3 solution achieves higher yield.Moreover,aqueous Na2CO3 as a solvent has various advantages including non-toxicity,inflammable,non-corrosive and low cost,which ensure this UAE method is a superior method with high utilizing prospect.展开更多
[Objectives]To determine the optimum technological conditions of ultrasound-assisted extraction of polysaccharides from Ajuga ciliata Bunge.[Methods]In this study,Ajuga ciliata Bunge was used as raw material,and an or...[Objectives]To determine the optimum technological conditions of ultrasound-assisted extraction of polysaccharides from Ajuga ciliata Bunge.[Methods]In this study,Ajuga ciliata Bunge was used as raw material,and an orthogonal experiment was designed based on the single factor experiment to investigate the effects of ultrasonic time,solid-liquid ratio,ultrasonic temperature and ultrasonic power on the extraction rate of polysaccharides from A.ciliata Bunge(Fujian).Range analysis,variance analysis and SSR test of significant differences between groups were carried out with SPSS 20.0,and the test results were verified.[Results]Under the conditions of ultrasonic temperature of 85℃,ultrasonic time of 80 min,solid-liquid ratio of 1∶15 g/mL and ultrasonic power of 500 W,the yield of polysaccharides from A.ciliata Bunge(Fujian)was the best.[Conclusions]This study can provide theoretical basis for the application of A.ciliata Bunge(Fujian).展开更多
Walnuts are one of nature’s more waste-heavy products. 67% of the nut is shell and husk, low value by-products that are rich in phenolic compounds. The phenolic compounds extracted from walnut shells are potentially ...Walnuts are one of nature’s more waste-heavy products. 67% of the nut is shell and husk, low value by-products that are rich in phenolic compounds. The phenolic compounds extracted from walnut shells are potentially good natural sources of antioxidants for the food and pharmaceutical industries. In this study, phenolic compounds were extracted using an ultrasonic bath, an ultrasonic probe and a standard shaking method. The extraction yield achieved with an ultrasonic probe was 51.2 mg GAE/g DW, two times higher than both the shaking method and the ultrasonic bath method which were 20.6 mg GAE/g DW and 25.8 mg GAE/g DW, respectively. Phenolic extraction was further improved by a size reduction of the walnut shells. The best extraction yield of 52.8 mg GAE/g DW was attained when the particle size was between 45 - 100 mesh. The ultrasonic probe treatment is the best method for extraction of phenolic compounds from walnut shells. Scanning electron microscopy (SEM) imaging indicated that the ultrasonic probe treatment could better rupture the hard structure of the cells, increasing the penetration of solvents and thus the extraction yield.展开更多
Objective: To reach the recovery and identification of antioxidant polyphenolic compounds from Nephelium lappaceum L.(Mexican variety) husk using ultrasound-assisted extraction and liquid chromatography/mass spectrome...Objective: To reach the recovery and identification of antioxidant polyphenolic compounds from Nephelium lappaceum L.(Mexican variety) husk using ultrasound-assisted extraction and liquid chromatography/mass spectrometry as well as the in vitro antioxidant activity. Methods: Rambutan husk extracts were obtained by ultrasound-assisted extraction, mass/volume ratio, water/ethanol percentage and extraction time were evaluated. Once the best extraction condition of polyphenolic compounds was defined, a polyphenolic fraction was recovered using Ambetlite XAD-16. The total content of antioxidant polyphenolic compounds was determined by summation of the total hydrolysable polyphenol and total condensed polyphenol contents. Recovered compounds were identified by FTIR(ATR) spectroscopy and HPLC/ESI/MS. The antioxidant activity was carried out by ABTS, DPPH and lipid oxidation inhibition in vitro methods. Results: In Mexican variety rambutan husk, the total polyphenolic content was 487.67 mg/g, after ultrasound-assisted extraction. According to the HPLC/ESI/MS analysis 12 antioxidant polyphenolic compounds were identified, mostly ellagitannins such as geraniin, corilagin and ellagic acid. The antioxidant activity determined by ABTS, DPPH and lipid oxidation inhibition methods was demonstrated. The main functional groups of the identified compounds were determined by FTIR analysis. Conclusions: It was demonstrated that ultrasound-assisted extraction was effective and allowed the extraction and recovery of antioxidant polyphenolic compounds. Furthermore Mexican variety rambutan husk is an important source for recovering polyphenolic compounds with antioxidant activity, these compounds have potential application for the treatment/prevention of various diseases related to cancer and pathogenic microorganisms.展开更多
Bound phenolic compounds from the residue of Apocynum venetum(A.venetum)tea were released by alkaline digestion with sonication,followed by extraction using ethyl acetate(EtOAc).The fragment ions of compounds in free ...Bound phenolic compounds from the residue of Apocynum venetum(A.venetum)tea were released by alkaline digestion with sonication,followed by extraction using ethyl acetate(EtOAc).The fragment ions of compounds in free and bound forms were identified by liquid chromatography electrospray ionization tandem mass spectrometry(LC-ESI-MS/MS)in both positive and negative modes.Further investigation of chemical constituents in the EtOAc extract led to the isolation of eleven individual compounds,and their chemical structures were identified as(−)-epicatechin(1),(−)-loliolide(2),(−)-syringaresinol-4-O-β-D-glucopyranoside(3),alloside of benzyl alcohol(4),3-[(6-O-hexopyranosylhexopyranosyl)oxy]-2-(palmitoyloxy)propyl(9Z,12Z,15Z)-9,12,15-octadecatrienoate(5),apocynoside I(6),quercetin-3-O-β-D-glucopyranoside(7),kaempferol-3-O-β-D-glucopyranoside(8),[1-acetyloxy-3-[3,4,5-trihydroxy-6-[[3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxymethyl]oxan-2-yl]oxypropan-2-yl]hexadecanoate(9),1-stearoyl-2-palmitoyl-sn-glycerol(10),and 3-hexene-l-O-β-D-glucoside(11)using a series of spectroscopic methods.Compounds 2–5 and 9–11 were isolated for the first time from A.venetum,while antioxidant experiments showed that compounds 1,7,and 8 displayed strong DPPH and ABTS+radical scavenging activities.This study represents the first investigation of bound phenolic compounds with potential health benefits in the residue of A.venetum tea.展开更多
The oil yield of oil shale was evaluated by Fourier transform infrared(FTIR) spectrometry coupled with ultrasound-assisted extraction. The extraction conditions, including the amount of sample, extraction time and e...The oil yield of oil shale was evaluated by Fourier transform infrared(FTIR) spectrometry coupled with ultrasound-assisted extraction. The extraction conditions, including the amount of sample, extraction time and extrac- tion temperature, were examined and optimized. Twenty-four oil shale samples were collected and divided into calibration set and prediction set randomly with a ratio of 2:1. The oil yields of all the samples were determined by the routine method(low-temperature retorting) for reference. The linear regression(LR) equations of oil yield vs. the total area of the spectrum peaks in a wavenumber range of 3100--2800 cm-1 as well as the sum of absorbance of three absorption peaks(2855, 2927 and 2955 cm-l), and the multiple linear regression(MLR) model of oil yield vs. the absorbances of the three absorption peaks were constructed with the samples in calibration set and applied to the evaluation of the oil yields of the samples in prediction set, respectively. The results show that the MLR model provides more accurate predictions than the other LR two equations. The determination coefficient(P2p ), the root- mean-square error of prediction(RMSEP) and the residual prediction deviation(RPD) of the MLR model are 0.9616, 0.6458 and 3.6, respectively. The present method is a rapid and effective alternative to the routine low-temperature retorting method.展开更多
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
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
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
For the efficient extraction of kamebakaurin(KA), the ultrasound-assisted extraction(UAE) of KA from Rabdosia excisa(R, excisa) via response surface methodology(RSM) was investigated with high-performance liqu...For the efficient extraction of kamebakaurin(KA), the ultrasound-assisted extraction(UAE) of KA from Rabdosia excisa(R, excisa) via response surface methodology(RSM) was investigated with high-performance liquid chromatography(HPLC). Effects of the experimental parameters such as extraction solvent, ratio of liquid to plant material, extraction time and extraction temperature on the extracting efficiency of KA from R. excisa were evaluated, and the purity of KA in residual was calculated. The optimized conditions were 65.5%(volume fraction) acetone, 35 ℃, time of 24.6 min with ultrasound of 80 W/L, 40 kHz, ratio of liquid to plant material at 30:1(mL/g). The maximum yield of KA is 0.708 mg/kg, with mean purity of 6.09%, indicating that ultrasound-assisted extraction is a feasible and useful method for extracting KA from R. excisa.展开更多
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
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
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
The spatial distributions of different kinds of ions are usually not completely the same in the process of extracting.In order to study the reason for the different characteristics of ion extraction, a simplified simu...The spatial distributions of different kinds of ions are usually not completely the same in the process of extracting.In order to study the reason for the different characteristics of ion extraction, a simplified simulation model of Cu+ andCr+ ions extraction process was established by 2D3V (two-dimensional in space and three- dimensional in velocity space)particle-in-cell (PIC) method. The effects of different extraction voltages from 0 V to 500 V on the density distribution ofCu+ and Cr+ ions and the change of plasma emission surface were analyzed. On the basis of this model, the ion densitydistribution characteristics of Cu+ ions mixed with Li+, Mg+, K+, Fe+, Y+, Ag+, Xe+, Au+, and Pb+ ions respectivelyunder 200-V extraction voltage are further simulated, and it is revealed that the atomic mass of the ions is the key reason fordifferent ion density distributions when different kinds of ions are mixed and extracted, which provides support for furtherunderstanding of ion extraction characteristics.展开更多
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
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
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
基金Supported by Hunan Provincial University Innovation Platform Open Fund Project(19K049)。
文摘With Pueraria edulis from different habitats in Yunnan Province,Guangdong Province and Guangxi Zhuang autonomous region as materials,the medicinal materials of P.edulis were extracted by ethanol condensation reflux extraction and ultrasound-assisted extraction,and the effects of different extraction methods the contents of total flavonoids in P.edulis from different areas were compared.The results showed that the best extraction time for P.edulis in Yunnan Province was 20 min,and that for Guangdong and Guangxi Zhuang Autonomous Region was 30 min.The yield of total flavonoids from P.edulis extracted by the condensation reflux extraction method was relatively better.The content of total flavonoids in P.edulis in Yunnan was the highest with an average content of 0.2557%,while the average content of total flavonoids in P.edulis in Guangdong was the lowest with an average content of 0.2108%.
基金Supported by National Natural Science Foundation of China(No.31101781)China Scholarship Council(CSC)+1 种基金Science and Technology Development Program of Jilin Province(No.20140204022NY)Interdisciplinary Innovation Fund of Jilin University(No.905070166006,No.450060481143)~~
文摘[Objective] This study aimed to investigate the optimal technological condi- tions for ultrasouqd-assisted extraction of polysaccharides from Pinus tabulaeformis seed shells. [Melhod] Polysaccharides were extracted from P. tabulaeformis seed shells by ultrasound-assisted hot water extraction method and detected by phenol- concentrated sulfuric acid method. The effect of extraction temperature, extraction duration, solid-liquid ratio and extraction frequency on the extraction of polysaccha- rides was investigated using single-factor gradient experiment and the extraction conditions for polysaccharides from P. tabulaeformis seed shells were optimized us- ing L9(34) orthogonal design. [Result] The content of polysaccharides extracted twice at 60 ℃ for 25 min with solid-liquid ratio of 1:3.5 reached the maximum. The re- covery rate (n=-5) ranged from 97.71% to 100.67% and RSD was 1.56%, suggesting high stability. [Conclusion] A simple and efficient method for ultrasound-assisted ex- traction of polysaccharides from P. tabulaeformis seed shells was established in this study, which laid solid foundation for the development and utilization of abandoned pine nut shell resources.
基金Supported by Science and Technology Project of Beijing Education Commission (KM200811417002)~~
文摘[Objective] The paper was to optimize ultrasound-assisted extraction of proacyanidins from purple cabbage. [Method] The ultrasound-assisted extraction technology was used to study the extraction of proacyanidins from purple cabbage. The effect of ethanol concentration, temperature, time, material-solution ratio and the power of ultrasound on extracting efficiency were studied by single-factor experiment. Based on this, L16(4%orthogonal test were conducted to determine the optimal condi- tion for extraction of proacyanidins from purple cabbage. [Result] The optimal condi- tion for extraction of proacyanidins from purple cabbage was as follows: ethanol concentration 50%, extraction temperature 50℃, extraction time 1 h, extraction power 540 W, material-liquid ratio 1:20. The extraction rate of procyanidins under this condition reached 104.8 mg/g. [Conclusion] The study provided a theoretical basis for scientific and reasonable utilization of procyanidins in purple cabbage.
基金supported by the "948" project of State Forestry Administration (No. 2011-4-16)
文摘Naturally occurring camptothecin(CPT) is an important source of chemotherapeutic agents.The extraction from Camptotheca acuminata is still the main approach to obtain CPT compared with total synthesis.In the present study,ultrasound-assisted extractions(UAE) of CPT from C.acuminata seeds with alkaline solutions were investigated and CPT yield were determined by High Performance Liquid Chromatography.The conditions of alkaline species and concentrations,extraction time,extraction temperature and ultrasonic power were optimized.Results show that both Na3PO4 and Na2CO3 solutions gain good extraction yields,whereas Na3PO4 solution has stronger basicity and need higher concentration than Na2CO3 solution does,thus aqueous Na2CO3 is more beneficial for the extraction.The optimal condition was ultrasonically extracted with 0.5% aqueous Na2CO3 at 50°C and ultrasonic power of 400 W for 60 min.Comparing with UAE with ethanol,the extraction with 0.5% Na2CO3 solution achieves higher yield.Moreover,aqueous Na2CO3 as a solvent has various advantages including non-toxicity,inflammable,non-corrosive and low cost,which ensure this UAE method is a superior method with high utilizing prospect.
基金Supported by Fujian College Students Innovation and Entrepreneurship Training Program in 2019(201912631026)Innovation and Entrepreneurship Training Program for College Students of Xiamen Medical College(201812631052,201912631057).
文摘[Objectives]To determine the optimum technological conditions of ultrasound-assisted extraction of polysaccharides from Ajuga ciliata Bunge.[Methods]In this study,Ajuga ciliata Bunge was used as raw material,and an orthogonal experiment was designed based on the single factor experiment to investigate the effects of ultrasonic time,solid-liquid ratio,ultrasonic temperature and ultrasonic power on the extraction rate of polysaccharides from A.ciliata Bunge(Fujian).Range analysis,variance analysis and SSR test of significant differences between groups were carried out with SPSS 20.0,and the test results were verified.[Results]Under the conditions of ultrasonic temperature of 85℃,ultrasonic time of 80 min,solid-liquid ratio of 1∶15 g/mL and ultrasonic power of 500 W,the yield of polysaccharides from A.ciliata Bunge(Fujian)was the best.[Conclusions]This study can provide theoretical basis for the application of A.ciliata Bunge(Fujian).
文摘Walnuts are one of nature’s more waste-heavy products. 67% of the nut is shell and husk, low value by-products that are rich in phenolic compounds. The phenolic compounds extracted from walnut shells are potentially good natural sources of antioxidants for the food and pharmaceutical industries. In this study, phenolic compounds were extracted using an ultrasonic bath, an ultrasonic probe and a standard shaking method. The extraction yield achieved with an ultrasonic probe was 51.2 mg GAE/g DW, two times higher than both the shaking method and the ultrasonic bath method which were 20.6 mg GAE/g DW and 25.8 mg GAE/g DW, respectively. Phenolic extraction was further improved by a size reduction of the walnut shells. The best extraction yield of 52.8 mg GAE/g DW was attained when the particle size was between 45 - 100 mesh. The ultrasonic probe treatment is the best method for extraction of phenolic compounds from walnut shells. Scanning electron microscopy (SEM) imaging indicated that the ultrasonic probe treatment could better rupture the hard structure of the cells, increasing the penetration of solvents and thus the extraction yield.
文摘Objective: To reach the recovery and identification of antioxidant polyphenolic compounds from Nephelium lappaceum L.(Mexican variety) husk using ultrasound-assisted extraction and liquid chromatography/mass spectrometry as well as the in vitro antioxidant activity. Methods: Rambutan husk extracts were obtained by ultrasound-assisted extraction, mass/volume ratio, water/ethanol percentage and extraction time were evaluated. Once the best extraction condition of polyphenolic compounds was defined, a polyphenolic fraction was recovered using Ambetlite XAD-16. The total content of antioxidant polyphenolic compounds was determined by summation of the total hydrolysable polyphenol and total condensed polyphenol contents. Recovered compounds were identified by FTIR(ATR) spectroscopy and HPLC/ESI/MS. The antioxidant activity was carried out by ABTS, DPPH and lipid oxidation inhibition in vitro methods. Results: In Mexican variety rambutan husk, the total polyphenolic content was 487.67 mg/g, after ultrasound-assisted extraction. According to the HPLC/ESI/MS analysis 12 antioxidant polyphenolic compounds were identified, mostly ellagitannins such as geraniin, corilagin and ellagic acid. The antioxidant activity determined by ABTS, DPPH and lipid oxidation inhibition methods was demonstrated. The main functional groups of the identified compounds were determined by FTIR analysis. Conclusions: It was demonstrated that ultrasound-assisted extraction was effective and allowed the extraction and recovery of antioxidant polyphenolic compounds. Furthermore Mexican variety rambutan husk is an important source for recovering polyphenolic compounds with antioxidant activity, these compounds have potential application for the treatment/prevention of various diseases related to cancer and pathogenic microorganisms.
文摘Bound phenolic compounds from the residue of Apocynum venetum(A.venetum)tea were released by alkaline digestion with sonication,followed by extraction using ethyl acetate(EtOAc).The fragment ions of compounds in free and bound forms were identified by liquid chromatography electrospray ionization tandem mass spectrometry(LC-ESI-MS/MS)in both positive and negative modes.Further investigation of chemical constituents in the EtOAc extract led to the isolation of eleven individual compounds,and their chemical structures were identified as(−)-epicatechin(1),(−)-loliolide(2),(−)-syringaresinol-4-O-β-D-glucopyranoside(3),alloside of benzyl alcohol(4),3-[(6-O-hexopyranosylhexopyranosyl)oxy]-2-(palmitoyloxy)propyl(9Z,12Z,15Z)-9,12,15-octadecatrienoate(5),apocynoside I(6),quercetin-3-O-β-D-glucopyranoside(7),kaempferol-3-O-β-D-glucopyranoside(8),[1-acetyloxy-3-[3,4,5-trihydroxy-6-[[3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxymethyl]oxan-2-yl]oxypropan-2-yl]hexadecanoate(9),1-stearoyl-2-palmitoyl-sn-glycerol(10),and 3-hexene-l-O-β-D-glucoside(11)using a series of spectroscopic methods.Compounds 2–5 and 9–11 were isolated for the first time from A.venetum,while antioxidant experiments showed that compounds 1,7,and 8 displayed strong DPPH and ABTS+radical scavenging activities.This study represents the first investigation of bound phenolic compounds with potential health benefits in the residue of A.venetum tea.
基金the National Innovation Project of Production-Study-Research-Application of China(No.OSR-02-04), the Research Fund for the Doctoral Program of Higher Education of China(No.20130061110068) and the National Natural Science Foundation of China(No.21207047).
文摘The oil yield of oil shale was evaluated by Fourier transform infrared(FTIR) spectrometry coupled with ultrasound-assisted extraction. The extraction conditions, including the amount of sample, extraction time and extrac- tion temperature, were examined and optimized. Twenty-four oil shale samples were collected and divided into calibration set and prediction set randomly with a ratio of 2:1. The oil yields of all the samples were determined by the routine method(low-temperature retorting) for reference. The linear regression(LR) equations of oil yield vs. the total area of the spectrum peaks in a wavenumber range of 3100--2800 cm-1 as well as the sum of absorbance of three absorption peaks(2855, 2927 and 2955 cm-l), and the multiple linear regression(MLR) model of oil yield vs. the absorbances of the three absorption peaks were constructed with the samples in calibration set and applied to the evaluation of the oil yields of the samples in prediction set, respectively. The results show that the MLR model provides more accurate predictions than the other LR two equations. The determination coefficient(P2p ), the root- mean-square error of prediction(RMSEP) and the residual prediction deviation(RPD) of the MLR model are 0.9616, 0.6458 and 3.6, respectively. The present method is a rapid and effective alternative to the routine low-temperature retorting method.
文摘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.
基金National Natural Science Foundation of China(Nos.42071444,42101444)。
文摘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.
基金the Science and Technology Key Project of Anhui Province,China(No.2022e03020004).
文摘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.
基金the National Natural Science Foundation of China,the Postdoctoral Foundation of Jiangsu Province,China,the China Postdoctoral Science Foundation
文摘For the efficient extraction of kamebakaurin(KA), the ultrasound-assisted extraction(UAE) of KA from Rabdosia excisa(R, excisa) via response surface methodology(RSM) was investigated with high-performance liquid chromatography(HPLC). Effects of the experimental parameters such as extraction solvent, ratio of liquid to plant material, extraction time and extraction temperature on the extracting efficiency of KA from R. excisa were evaluated, and the purity of KA in residual was calculated. The optimized conditions were 65.5%(volume fraction) acetone, 35 ℃, time of 24.6 min with ultrasound of 80 W/L, 40 kHz, ratio of liquid to plant material at 30:1(mL/g). The maximum yield of KA is 0.708 mg/kg, with mean purity of 6.09%, indicating that ultrasound-assisted extraction is a feasible and useful method for extracting KA from R. excisa.
基金financially supported by the National Natural Science Foundation of China(No.52072322)the Department of Science and Technology of Sichuan Province,China(Nos.23GJHZ0147,23ZDYF0262,2022YFG0294,and 2019-GH02-00052-HZ)。
文摘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.
文摘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.
基金supported by the National Natural Science Foundation of China(Nos.U1804263,U1736214,62172435)the Zhongyuan Science and Technology Innovation Leading Talent Project(No.214200510019).
文摘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.
基金the Presidential Foundation of China Academy of Engineering Physics(Grant No.YZJJZQ2022016)the National Natural Science Foun-dation of China(Grant No.52207177).
文摘The spatial distributions of different kinds of ions are usually not completely the same in the process of extracting.In order to study the reason for the different characteristics of ion extraction, a simplified simulation model of Cu+ andCr+ ions extraction process was established by 2D3V (two-dimensional in space and three- dimensional in velocity space)particle-in-cell (PIC) method. The effects of different extraction voltages from 0 V to 500 V on the density distribution ofCu+ and Cr+ ions and the change of plasma emission surface were analyzed. On the basis of this model, the ion densitydistribution characteristics of Cu+ ions mixed with Li+, Mg+, K+, Fe+, Y+, Ag+, Xe+, Au+, and Pb+ ions respectivelyunder 200-V extraction voltage are further simulated, and it is revealed that the atomic mass of the ions is the key reason fordifferent ion density distributions when different kinds of ions are mixed and extracted, which provides support for furtherunderstanding of ion extraction characteristics.
文摘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.
基金supported by the National Natural Science Foundation of China(22125802,22078010).
文摘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.
基金Project supported by Presidential Foundation of CAEP (Grant No.YZJJZQ2022016)the National Natural Science Foundation of China (Grant No.52207177)。
文摘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.