期刊文献+
共找到14篇文章
< 1 >
每页显示 20 50 100
Comparison of Extraction Techniques with Different Solvents for DDT Analogues in Sediments 被引量:3
1
作者 LANG Yin-Hai JIANG Xin +1 位作者 D. MARTENS ZHAO Qi-Guo 《Pedosphere》 SCIE CAS CSCD 2005年第5期628-633,共6页
Four techniques, Soxhlet extraction (SOX), ultrasonic extraction (USE), fluidized-bed extraction (FBE) and acce-lerated solvent extraction (ASE) with different solvents (methanol, hexane/acetone and acetonitrile) were... Four techniques, Soxhlet extraction (SOX), ultrasonic extraction (USE), fluidized-bed extraction (FBE) and acce-lerated solvent extraction (ASE) with different solvents (methanol, hexane/acetone and acetonitrile) were used for theextraction of DDT analogues in sediments. Results revealed that the four extraction techniques had high recoveries (>86.0%) with low standard deviations (< 12.0%) for most of DDT analogues, meaning that they could all successfully extractDDT analogues in sediments. Accelerated solvent extraction using methanol and hexane/acetone (1:1), fluidized-bedextraction using hexane/acetone (1:1) and the ultrasonic extraction using hexane/acetone (1:1) were comparable or betterthan Soxhlet extraction using hexane/acetone (1:1). Considering solvent- and time-consumption, level of automation,and environmental risk, accelerated solvent extraction with hexane/acetone (1:1) was better than the other extractiontechniques. 展开更多
关键词 DDT analogues extraction techniques SEDIMENT solvents
下载PDF
Study on Extraction Techniques of Celastrol from Celastrus orbiculatus Thunb.
2
作者 Wenhua ZHANG Congkui TIAN +1 位作者 Tiancai ZHONG Zengbao WU 《Agricultural Biotechnology》 CAS 2022年第3期133-135,共3页
[Objectives]This study was conducted to investigate the extraction technology of celastrol from Celastrus orbiculatus Thunb.[Methods]Solvent ultrasonic extraction was selected,and with the content of celastrol as the ... [Objectives]This study was conducted to investigate the extraction technology of celastrol from Celastrus orbiculatus Thunb.[Methods]Solvent ultrasonic extraction was selected,and with the content of celastrol as the evaluation index,the effects of different solvents,extraction time,temperatures and material-to-liquid ratios on the extraction rate of celastrol were investigated by single factor and orthogonal experiments.[Results]The optimal extraction conditions were as follows:a solvent ratio of petroleum ether to ethyl acetate at 1∶1,a ratio of solvent to material at 10∶1(v/w),extraction time of 30 min,and an extraction temperature at 30℃.[Conclusions]This method has high extraction rate,and is simple and feasible. 展开更多
关键词 CELASTROL Celastrus orbiculatus Thunb. Extraction technique
下载PDF
Early Diagnosis of Lung Tumors for Extending Patients’ Life Using Deep Neural Networks
3
作者 A.Manju R.Kaladevi +6 位作者 Shanmugasundaram Hariharan Shih-Yu Chen Vinay Kukreja Pradip Kumar Sharma Fayez Alqahtani Amr Tolba Jin Wang 《Computers, Materials & Continua》 SCIE EI 2023年第7期993-1007,共15页
The medical community has more concern on lung cancer analysis.Medical experts’physical segmentation of lung cancers is time-consuming and needs to be automated.The research study’s objective is to diagnose lung tum... The medical community has more concern on lung cancer analysis.Medical experts’physical segmentation of lung cancers is time-consuming and needs to be automated.The research study’s objective is to diagnose lung tumors at an early stage to extend the life of humans using deep learning techniques.Computer-Aided Diagnostic(CAD)system aids in the diagnosis and shortens the time necessary to detect the tumor detected.The application of Deep Neural Networks(DNN)has also been exhibited as an excellent and effective method in classification and segmentation tasks.This research aims to separate lung cancers from images of Magnetic Resonance Imaging(MRI)with threshold segmentation.The Honey hook process categorizes lung cancer based on characteristics retrieved using several classifiers.Considering this principle,the work presents a solution for image compression utilizing a Deep Wave Auto-Encoder(DWAE).The combination of the two approaches significantly reduces the overall size of the feature set required for any future classification process performed using DNN.The proposed DWAE-DNN image classifier is applied to a lung imaging dataset with Radial Basis Function(RBF)classifier.The study reported promising results with an accuracy of 97.34%,whereas using the Decision Tree(DT)classifier has an accuracy of 94.24%.The proposed approach(DWAE-DNN)is found to classify the images with an accuracy of 98.67%,either as malignant or normal patients.In contrast to the accuracy requirements,the work also uses the benchmark standards like specificity,sensitivity,and precision to evaluate the efficiency of the network.It is found from an investigation that the DT classifier provides the maximum performance in the DWAE-DNN depending on the network’s performance on image testing,as shown by the data acquired by the categorizers themselves. 展开更多
关键词 Lung tumor deep wave auto encoder decision tree classifier deep neural networks extraction techniques
下载PDF
A review on the extraction and separation of andrographolide from Andrographis paniculata:extraction selectivity,current challenges and strategies
4
作者 Di Liang Wei-Mei Zhang +4 位作者 Xu Liang Hong-Yue Tian Xue-Min Zhang Xia Li Wen-Yuan Gao 《Traditional Medicine Research》 2023年第7期11-23,共13页
Andrographolide is the main active ingredient of Andrographis paniculata(Burm.f.)Nees,known as“natural antibiotic”.Here,for the purpose of discovering a more efficient,low-cost extraction and separation method,the r... Andrographolide is the main active ingredient of Andrographis paniculata(Burm.f.)Nees,known as“natural antibiotic”.Here,for the purpose of discovering a more efficient,low-cost extraction and separation method,the research status of andrographolide was reviewed.At present,researches only take extraction rate as the only index to optimize extraction parameters,but ignores the importance of extraction selectivity.It is usually meaningless to blindly pursue the extraction rate without considering the difficulty and cost of subsequent separation.So,factors affecting extraction selectivity such as solvent choice,temperature and physicochemical effects caused by extraction technique itself,are first discussed.Different extraction techniques for andrographolide were discussed by comparing the selectivity,efficiency and cost of extraction.The separation procedures of andrographolide such as decolorization,impurity removal,crystallization,membrane separation,solid-phase extraction and partition chromatography and their challenges and possible strategies are also discussed.It is hoped that this review can provide guidance for researchers who are committed to advancing the field of andrographolide extraction and purification. 展开更多
关键词 ANDROGRAPHOLIDE extraction techniques extraction selectivity SEPARATION
下载PDF
Research Progress of Total Flavonoids from Plants in Trib.Lorantheae
5
作者 Jiemei LIANG Li LI +5 位作者 Lanlan FAN Hua ZHU Qiaowen ZHOU Mingjuan HUANG Qiulian WU Xue WANG 《Agricultural Biotechnology》 2023年第6期12-18,共7页
Trib.Lorantheae is one of the important medicinal plants in traditional medicine.There are 41 genera,6 genera of which are produced in China,mainly distributed in Southwest China,South China and Central South China.Th... Trib.Lorantheae is one of the important medicinal plants in traditional medicine.There are 41 genera,6 genera of which are produced in China,mainly distributed in Southwest China,South China and Central South China.There are many kinds of plants in this family,and 22 species can be used as Chinese medicinal materials in China.The branches and leaves of Trib.Lorantheae are rich in flavonoids,alkaloids,terpenoids,polysaccharides,organic acids and other functional substances,among which flavonoids are one of the important chemical components to exert pharmacological activity,and play an important role in hypoglycemic,lipid-lowering,anti-inflammatory,anti-tumor,anti-oxidation,anti-osteoporosis and so on.In this paper,the chemical composition,extraction method,component analysis and pharmacological action of flavonoids in Trib.Lorantheae plants were reviewed,in order to provide scientific reference for further development and clinical application of flavonoids in Trib.Lorantheae plants. 展开更多
关键词 Trib.Lorantheae Total flavonoids Extraction techniques Analytic procedure Pharmacological effect
下载PDF
Extraction and Antioxidant Functions of Polysaccharides from Seaweed 被引量:2
6
作者 Hongrui LI Jie YAN +2 位作者 Senze QIN Yanqing CHEN Haixiong LA 《Agricultural Biotechnology》 CAS 2015年第6期73-77,共5页
Dried seaweed powder was used as the raw material to extract polysaccharides by ethanol precipitation after water bath. Extraction temperature, extrac- tion duration, solution pH and solid to liquid ratio were selecte... Dried seaweed powder was used as the raw material to extract polysaccharides by ethanol precipitation after water bath. Extraction temperature, extrac- tion duration, solution pH and solid to liquid ratio were selected as technical parameters which required to be optimized. With the extraction rate of seaweed poly- saccharides as an index, single-factor experiment and orthogonal experiment were carried out to determine the optimal extraction technique. Seaweed polysaceharides were extracted with the optimal technical parameters to analyze the biological activities. Savage method was used to process seaweed polysaceharide extract. In vitro biological activities of preliminarily purified seaweed polysaeeharides were investigated successively, including reducing ability, antioxidant ability and antibacterial activity. The results showed that there was a positive correlation between polysaccharide concentration and its reducing ability, antioxidant ability and antibacterial activity. Furthermore, there was also a correlation among the reducing ability, antioxidant ability and antibacterial activity of seaweed polysaecharides; the relation- ship between each two of these three indicators was similar to positive linear correlation. 展开更多
关键词 Seaweed polysaccharide Extraction technique Orthogonal experiment Antioxidant ability Reducing ability Antibacterial activity
下载PDF
Evaluating the performances of accelerated-solvent extraction, microwave-assisted extraction, and ultrasonic-assisted extraction for determining PCBs, HCHs and DDTs in sediments 被引量:1
7
作者 张蓬 葛林科 +1 位作者 周传光 姚子伟 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2011年第5期1103-1112,共10页
Three extraction techniques have been recently used for the quantitative extraction of semi-volatile organic pollutants in sediments, i.e. accelerated solvent extraction (ASE), microwave assisted extraction (MAE) ... Three extraction techniques have been recently used for the quantitative extraction of semi-volatile organic pollutants in sediments, i.e. accelerated solvent extraction (ASE), microwave assisted extraction (MAE) and ultrasonic assisted extraction (UAE). However, their extraction efficiencies have rarely been quantitatively compared using rigorous mathematical methods. In this paper, one-way analysis of variance (ANOVA) was employed to evaluate the performance of ASE, MAE and UAE in the overall extraction of PCBs, DDTs and HCHs by analysis of their recoveries from the Standard Reference Material IAEA-417, a sediment sample certified by many international laboratories. Conclusions were drawn at a significance level of P〈 0.05. No significant differences were found among the mean values for method recoveries using ASE, MAE and UAE. The mean values for real recoveries using ASE and MAE were nearly identical, but the real recovery using UAE was much lower. The concentrations of all PCBs, DDTs and HCHs except for CB52 and o,p'-DDT using UAE were the lowest. Comparing the results obtained using ASE with MAE, the concentrations of CB28, CB52, CB138, ct-HCH, [3-HCH, p,p'-DDE and p,p'-DDD were nearly identical, while the concentrations of other compounds were significantly different. Based on the low recoveries, it was concluded that UAE is a relatively inefficient extraction method, while ASE and MAE are equivalent methods. Taking into consideration the relative standard deviation (RSD) values, solvent volume, extraction time, and purchasing costs of the apparatus, MAE was considered superior to ASE for extraction of PCBs, DDTs and HCHs. 展开更多
关键词 extraction technique sediment PCB HCH DDT
下载PDF
A NEW SINGULARITY EXTRACTION TECHNIQUE FOR TDEFIE 被引量:1
8
作者 Liu Feng Zhou Dongming Cai Mingjuan Ren Meng He 3iangguo 《Journal of Electronics(China)》 2007年第5期686-689,共4页
A new singularity extraction technique is presented to calculate accurately the singular integrals in Time Domain Electric Field Integral Equation (TDEFIE).In singularity extraction pro- cedure,through the aid of the ... A new singularity extraction technique is presented to calculate accurately the singular integrals in Time Domain Electric Field Integral Equation (TDEFIE).In singularity extraction pro- cedure,through the aid of the first order Taylor series of time base function including time-retardation,the singularity of the integrand can be removed.The surface current density and backscattered far-field response of a conducting cube illuminated by a Gaussian plane wave is com- puted using the presented technique.Comparisons are made with the results obtained by the Inverse Discrete Fourier Transform (IDFT) of the frequency domain and the results obtained by using Ve- chinski's time averaging technique,which demonstrate that the presented method with this new time domain singularity extraction technique to solve TDEFIE is very accurate and stable. 展开更多
关键词 Singularity extraction technique Taylor series Time Domain Electric Field Integral Equation (TDEFIE)
下载PDF
Ultrasonic wave extraction and simultaneous analysis of polycyclic aromatic hydrocarbons (PAHs) and phthalic esters in soil
9
作者 ZHANG Yong-tao ZHAO Guo-xing +4 位作者 LIU Jing-shang ZHANG Li LI Xiao-ya GUI Jian-ye ZHANG Chen-ling 《Journal of Groundwater Science and Engineering》 2017年第3期249-253,共5页
A method is developed for detection of polycyclic aromatic hydrocarbons(PAHs) and Phthalic Acid Esters(PAEs) in soil samples. Ultrasonic Wave Extraction under airtight circumstances is adopted to extract the analytes ... A method is developed for detection of polycyclic aromatic hydrocarbons(PAHs) and Phthalic Acid Esters(PAEs) in soil samples. Ultrasonic Wave Extraction under airtight circumstances is adopted to extract the analytes in soil samples with n-hexane–acetone(V:V=1:1) as extraction solvent. This method has several advantages, including high extraction efficiency, short time, convenience and simplicity. It can be used to detect polycyclic aromatic hydrocarbons(PAHs) and Phthalic Acid Esters(PAEs) in soil. 展开更多
关键词 Polycyclic aromatic hydrocarbons Phthalic Acid Esters Ultrasonic assistant extraction technique
下载PDF
Injection and Extraction Techniques in Circular Accelerators
10
作者 唐靖宇 《Chinese Physics C》 SCIE CAS CSCD 北大核心 2008年第z1期256-258,共3页
Injection and extraction are usually the key systems in circular accelerators.They play important roles in transferring the beam from one stage acceleration to the other or to experimental stations.It is also in the i... Injection and extraction are usually the key systems in circular accelerators.They play important roles in transferring the beam from one stage acceleration to the other or to experimental stations.It is also in the injection and extraction regions where beam losses happen mostly.Due to the tight space and to reduce the perturbation to the circulating orbit,the devices are usually designed to meet special requirements such as compactness,small stray field,fast rise time or fall time,etc.Usual injection and extraction devices include septum magnets,kicker magnets, electrostatic deflectors,slow bump magnets and strippers.In spite of different accelerators and specification for the injection and extraction devices,many techniques are shared in the design and manufacturing.This paper gives a general review on the techniques employed in the major circular accelerators in China. 展开更多
关键词 injection extraction technique SEPTUM kicker slow bump electrostatic deflector STRIPPER
原文传递
Green Extraction of Bioactive Compounds from Microalgae 被引量:1
11
作者 Rocío Gallego Lidia Montero +2 位作者 Alejandro Cifuentes Elena Ibáñez Miguel Herrero 《Journal of Analysis and Testing》 EI 2018年第2期109-123,共15页
At present,there is an increasing demand for natural bioactive compounds able to provide health benefits when included and consumed in a functional food or in a nutraceutical.In this regard,microalgae are promising na... At present,there is an increasing demand for natural bioactive compounds able to provide health benefits when included and consumed in a functional food or in a nutraceutical.In this regard,microalgae are promising natural sources with great potential,not only considering that these organisms are largely underexplored,but also because microalgae can be produced at large scale and their chemical composition might be tuned to over-synthesize a particular target compound.The use of advanced sustainable extraction techniques to recover these bioactive compounds is a must nowadays.This work presents an overview on the use of compressed fluid-based extraction techniques to obtain bioactive compounds from microalgae that can be seen also as a first step towards its recovery at larger scale.When relevant,the description of the analytical procedure used to chemically characterize the bioactive compounds is also included. 展开更多
关键词 BIOACTIVES Compressed fluids Green extraction techniques MICROALGAE Pressurized liquids Supercritical fluids
原文传递
Citrus reticulata Blanco (the common mandarin) fruit:An updated review of its bioactive,extraction types,food quality,therapeutic merits,and bio-waste valorization practices to maximize its economic value 被引量:1
12
作者 Mohamed Shorbagi Nesrin M.Fayek +1 位作者 Ping Shao Mohamed A.Farag 《Food Bioscience》 SCIE 2022年第3期67-80,共14页
Fruits are regarded as the richest dietary sources of polyphenols,carotenoids,terpenoids,and limonoids,making them highly desired prospects for the functional food industry.Citrus waste that remains after fruit proces... Fruits are regarded as the richest dietary sources of polyphenols,carotenoids,terpenoids,and limonoids,making them highly desired prospects for the functional food industry.Citrus waste that remains after fruit processing is also regarded as a valuable source of value-added phytochemicals.A comprehensive analysis of mandarin composition as a determinant of fruit functional properties,health benefits,and valorization into useful products is represented together with the effect of different processes such as light,wax coating,auxin addition,ozone treatment,and ethylene degreening.Such reviewing evidence is an essential precondition for improving the selling market of mandarin and highlighting its waste valorization potential and its incorporation into useful products produced by pharmaceutical industries.In this study,the phytochemical and biological reports presented to emphasize the needed priority for agricultural techniques to provide a certain mandarin product or trait.In addition,the paper summarizes the optimum conditions applied for the updated extraction techniques for phenolic acids,flavonoids,and oils at a commercial scale from mandarin peels and to enhance its global marketing.A brief representation is given towards potential mandarin patents and the valorization of its bio-waste fruits into commercial products of added value.The review can guide researchers to produce future potentially marketed functional food enriched with mandarin extracts and/or bioactives. 展开更多
关键词 Citrus reticulata Phytochemical composition Biological effects Waste valorization Extraction techniques Processing effect
原文传递
On the applicability of the‘humic acids’nomenclature from natural ecosystems to engineering sciences 被引量:1
13
作者 Xinyu Zhao Beidou Xi +3 位作者 Wenbing Tan Xiang Li Qiuling Dang Renfei Li 《Environmental Science and Ecotechnology》 2021年第2期1-2,共2页
‘Humic acids(HA)’are the major constituents of natural organic matter(NOM)derived from the plant or biological residues by decomposition and synthesis in natural ecosystems.They have been defined as relatively high ... ‘Humic acids(HA)’are the major constituents of natural organic matter(NOM)derived from the plant or biological residues by decomposition and synthesis in natural ecosystems.They have been defined as relatively high molecular weight aggregates of macromolecules associations with series of highly reactive functional compounds,and considered to be as irreplaceable roles(such as the impact on global carbon and nitrogen dynamics,atmosphere,living plants,chemically reactive and NOM structure stabilization)in natural ecosystems[1]. 展开更多
关键词 Humic acid Engineering sciences Natural ecosystems Alkaline extraction technique
原文传递
Atmospheric Drying UHMWPE Membranes via Multiple Stage Extractant Exchange Drying Technique 被引量:1
14
作者 Jiayou Quan Qingquan Song +3 位作者 Junrong Yu Yan Wang Jing Zhu Zuming Hu 《Advanced Fiber Materials》 SCIE CAS 2022年第2期235-245,共11页
Ultra-high molecular weight polyethylene(UHMWPE)membranes were prepared by 5 wt%UHMWPE/parafn oil gels via thermally induced phase separation method and dried in air without signifcant collapse.The UHMWPE membranes we... Ultra-high molecular weight polyethylene(UHMWPE)membranes were prepared by 5 wt%UHMWPE/parafn oil gels via thermally induced phase separation method and dried in air without signifcant collapse.The UHMWPE membranes were annealed at 110℃ for increasing the pores size in order to decrease the capillary forces.Furthermore,a new multiple stage extractant exchange drying(MSEED)technique was adopted to decrease the shrinkage of the UHMWPE membranes.Specifcally,the parafn oil was extracted by dichloromethane,then dichloromethane was replaced by ethanol,next ethanol could be exchanged to other liquid which is non-afnity with UHMWPE,for example water.UHMWPE membranes(annealing for 25 min)dried by dichloromethane-ethanol-water-air process have the lowest volume shrinkage of 16.5%and the porosity is as high as 88.29%.Moreover,compared with supercritical CO_(2)(SC-CO_(2))drying,atmospheric drying UHMWPE membranes have a lower pure water permeance,but a higher carbon particles rejection. 展开更多
关键词 UHMWPE Atmospheric drying Supercritical CO_(2)drying Multiple stage extractant exchange drying technique
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部