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高良姜黄酮类物质提取工艺的研究 预览
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作者 程嘉怡 黄和 +1 位作者 曹湛慧 刘子聪 《农产品加工》 2019年第8期38-42,49共6页
以高良姜为原料,以黄酮提取率为指标,通过单因素试验和正交试验优化索氏提取法和超声波辅助法提取黄酮类物质的提取工艺,并比较其工艺条件。结果表明,索氏提取法最佳工艺为乙醇体积分数60%,料液比1∶40,提取3次,每次提取时间2h,黄酮类... 以高良姜为原料,以黄酮提取率为指标,通过单因素试验和正交试验优化索氏提取法和超声波辅助法提取黄酮类物质的提取工艺,并比较其工艺条件。结果表明,索氏提取法最佳工艺为乙醇体积分数60%,料液比1∶40,提取3次,每次提取时间2h,黄酮类物质提取率为76.3mg/g;超声波辅助法最佳工艺为乙醇体积分数50%,料液比1∶35,超声时间70min,超声功率400W,黄酮类物质提取率为94.6mg/g。因此,超声波辅助法的提取率较高、提取时间较短,更适于高良姜中黄酮类物质的提取。 展开更多
关键词 高良姜 黄酮类物质 提取 索氏提取法 超声波辅助法
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Evaluation of Phenolic Content and Antioxidant Activity of Aqueous Extracts of Three <i>Carica papaya</i>Varieties Cultivated in Senegal 预览
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作者 A?ssatou Alioune Gaye Oumar Ibn Khatab Cisse +3 位作者 Bou Ndiaye Nicolas Cyrille Ayessou Mady Cisse Codou Mar Diop 《食品与营养科学(英文)》 2019年第3期276-289,共14页
The aqueous extracts of different parts (old leaves (OL), young leaves (YL), peels (PE) and delipidated seed residues (DS)) of three varieties of papaya are studied. Extraction conditions are optimized: an extraction ... The aqueous extracts of different parts (old leaves (OL), young leaves (YL), peels (PE) and delipidated seed residues (DS)) of three varieties of papaya are studied. Extraction conditions are optimized: an extraction time of 20 minutes, a temperature of 70°C and a plant material/water mixture of 1% give the best yield of polyphenol. The amount of polyphenols, flavonoids, saponins and proanthocyanins of each aqueous extract was investigated. Antioxidant activities are measured using two different methods (DPPH and ABTS). The delipidated seeds (DS) of V1 have the highest total phenolic content (TPC = 72.56 ± 3.16 mg GAE/g) while they have the lowest total flavonoid content (TFC = 0.22 ± 0.01). With regard to saponins, the PE of V3 is much richer in saponins (194.03 ± 15.78 mg AeE/g) than all the other extracts studied. The OL of V2 and PE of V1 contain the most proanthocyanidins with very similar values of 2.51 ± 0.03 mg CE/g and 2.53 ± 0.34 mg CE/g respectively. The study of the antioxidant activities of the extracts showed a correlation between the amount of polyphenols and IC50. DPPH OL and YL V2, which are rich in polyphenols, have the lowest IC50 of 0.072 mg/ml and 0.080 mg/ml respectively, whereas for ABTS we have PE of V1 that is very rich in polyphenols which has the smallest IC50 value of 0.218 mg/ml. 展开更多
关键词 CARICA PAPAYA Extraction Antioxidant Polyphenols Flavonoids PROANTHOCYANIDINS SAPONINS
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气滞胃痛颗粒中挥发性成分提取工艺的优化 预览
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作者 郑鹏 赵昭 +2 位作者 李佳佳 顿佳颖 李春花 《中成药》 CAS CSCD 北大核心 2019年第6期1214-1218,共5页
目的优化气滞胃痛颗粒中挥发性成分的提取工艺。方法在单因素试验基础上,以加水量、浸泡时间、提取时间为影响因素,挥发油提取率及柠檬烯、α-香附酮、香附烯酮含有量的综合评分为评价指标,响应面法结合信息熵优化提取-共沸精馏耦合工... 目的优化气滞胃痛颗粒中挥发性成分的提取工艺。方法在单因素试验基础上,以加水量、浸泡时间、提取时间为影响因素,挥发油提取率及柠檬烯、α-香附酮、香附烯酮含有量的综合评分为评价指标,响应面法结合信息熵优化提取-共沸精馏耦合工艺。结果最佳条件为加水量13倍,浸泡时间1.1 h,提取时间6.5 h,综合评分0.922 2。结论该方法稳定可靠,可用于提取气滞胃痛颗粒中挥发性成分。 展开更多
关键词 气滞胃痛颗粒 挥发性成分 提取 提取-共沸精馏耦合 响应面法 信息熵
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Pressurized Synchronous Extraction of Volatile Oils, Total Flavonoids and Tannic Acid from Artemisia argyi 预览
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作者 Huasheng LI Zhenhua ZHOU +2 位作者 Hang LUO Yuting LI Yuan JIANG 《药用植物研究(英文版)》 2019年第4期54-59,共6页
[Objectives] This study aimed to optimize the conditions for pressurized synchronous extraction of volatile oils, total flavonoids and tannic acid from Artemisia argyi .[Methods] Single factor experiments and orthogon... [Objectives] This study aimed to optimize the conditions for pressurized synchronous extraction of volatile oils, total flavonoids and tannic acid from Artemisia argyi .[Methods] Single factor experiments and orthogonal experiments were conducted.[Results] Pressurization had a significant effect on the extraction rate of chemical constituents of A. argyi . The optimal conditions for pressurized synchronous extraction of volatile oils, total flavonoids and tannic acid from A. argyi were as follows: solvent concentration of 70%, solid to liquid ratio of 1∶ 30 (g/mL), extraction pressure of 0.9 MPa, extraction time of 40 min and extraction temperature of 90 ℃. Under the optimal extraction conditions, the yields of volatile oils, total flavonoids and tannic acid were 0.852%, 4.66% and 6.79%, respectively.[Conclusions] Compared with other extraction methods, the pressurized assistant solvent extraction method can achieve the synchronous extraction of volatile oils, total flavonoids and tannic acid from A. argyi . The process is stable, short in extraction time, high in solvent utilization rate and ideal in extraction effect of the three components from A. argyi . 展开更多
关键词 ARTEMISIA argyi PRESSURIZATION SYNCHRONOUS EXTRACTION EXTRACTION RATE PROCESS
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6种食用芳香植物挥发性成分的GC-MS/GC-O分析 预览
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作者 郭向阳 《农业工程学报》 CSCD 北大核心 2019年第18期299-307,共9页
挥发性成分是芳香植物具有多样风味及香气性能的物质基础。为研究常见可食用芳香植物的挥发性成分及其风味特性的异同,构建特色芳香植物风味数据库,利用气相色谱-质谱联用技术分析经顶空法萃取的6种食用芳香植物(薄荷、藿香、罗勒、丁... 挥发性成分是芳香植物具有多样风味及香气性能的物质基础。为研究常见可食用芳香植物的挥发性成分及其风味特性的异同,构建特色芳香植物风味数据库,利用气相色谱-质谱联用技术分析经顶空法萃取的6种食用芳香植物(薄荷、藿香、罗勒、丁香罗勒、香薷及密花香薷)的挥发性成分,经气相嗅辨仪对其挥发性成分进行香气描述分析,对比研究6种芳香植物挥发性成分的异同及香气性能的差异。结果表明:6种芳香植物香气主要由萜烯类、醇类、酮类、醛类成分组成,含有少量的酯类、杂环类及芳香族类化合物,多具有辛辣、刺激、樟脑样香气及清新的柠檬、柑橘风味。薄荷中以具花香和柠檬样香气的香叶醇、香茅醇及柠檬醛、香叶醛含量较多;藿香中以左旋薄荷酮及草蒿脑为主,具木香及大茴香似香气特征;罗勒中丙烯酸酯和芳樟醇是其主体成分,辛辣味突出,花香显;而丁香酚成就了丁香罗勒的主体风味,似丁香花香,具辛辣香气;香薷中以具柠檬样香气的D-柠檬烯、柠檬醛、γ-萜品烯为主,柠檬醛和香叶醛为密花香薷的主体成分,整体偏辛辣,花香透,伴柠檬样清新香气。不同的挥发性成分,以一定的比例及含量组成呈现了芳香植物的特征香气。研究结果可为特色芳香植物的品种选育、香气品质提升及风味性能的研究提供科学数据参考。 展开更多
关键词 挥发性有机物 风味 萃取 芳香植物 GC-MS GC-O 顶空萃取 香气描述
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Medical Knowledge Extraction and Analysis from Electronic Medical Records Using Deep Learning 预览
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作者 Peilin Li Zhenming Yuan +2 位作者 Wenbo Tu Kai Yu Dongxin Lu 《中国医学科学杂志:英文版》 CAS CSCD 2019年第2期133-139,共7页
Objectives Medical knowledge extraction (MKE) plays a key role in natural language processing (NLP) research in electronic medical records (EMR),which are the important digital carriers for recording medical activitie... Objectives Medical knowledge extraction (MKE) plays a key role in natural language processing (NLP) research in electronic medical records (EMR),which are the important digital carriers for recording medical activities of patients.Named entity recognition (NER) and medical relation extraction (MRE) are two basic tasks of MKE.This study aims to improve the recognition accuracy of these two tasks by exploring deep learning methods.Methods This study discussed and built two application scenes of bidirectional long short-term memory combined conditional random field (BiLSTM-CRF) model for NER and MRE tasks.In the data preprocessing of both tasks,a GloVe word embedding model was used to vectorize words.In the NER task,a sequence labeling strategy was used to classify each word tag by the joint probability distribution through the CRF layer.In the MRE task,the medical entity relation category was predicted by transforming the classification problem of a single entity into a sequence classification problem and linking the feature combinations between entities also through the CRF layer.Results Through the validation on the I2B2 2010 public dataset,the BiLSTM-CRF models built in this study got much better results than the baseline methods in the two tasks,where the F1-measure was up to 0.88 in NER task and 0.78 in MRE task.Moreover,the model converged faster and avoided problems such as overfitting.Conclusion This study proved the good performance of deep learning on medical knowledge extraction.It also verified the feasibility of the BiLSTM-CRF model in different application scenarios,laying the foundation for the subsequent work in the EMR field. 展开更多
关键词 MEDICAL knowledge EXTRACTION electronic MEDICAL record named ENTITY recognition MEDICAL relation EXTRACTION deep learning BIDIRECTIONAL long SHORT-TERM memory CONDITIONAL random field
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地基激光雷达提取大田玉米植株表型信息 预览
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作者 苏伟 蒋坤萍 +3 位作者 郭浩 刘哲 朱德海 张晓东 《农业工程学报》 EI CAS CSCD 北大核心 2019年第10期125-130,共6页
玉米个体表型信息对于玉米的高产高效发育规律研究、玉米遗传育种中基因型的确定具有重要意义,该文针对传统的玉米表型信息提取方法费时、费力、效率低下、主观性强等问题,提出一种基于TLS(terrestrial laser scanning,地面激光扫描)技... 玉米个体表型信息对于玉米的高产高效发育规律研究、玉米遗传育种中基因型的确定具有重要意义,该文针对传统的玉米表型信息提取方法费时、费力、效率低下、主观性强等问题,提出一种基于TLS(terrestrial laser scanning,地面激光扫描)技术的大田玉米个体表型信息提取方法。利用地基激光雷达获取毫米级精度的玉米个体植株三维点云数据并进行海量点云数据预处理,构建玉米叶片三角网模型和叶片骨架点云;基于叶片三角网提取绿叶叶面积,基于叶片骨架点云提取叶长和叶倾角,基于未去穗的玉米植株点云提取株高。试验结果与实地手动测量值相比,真实叶面积、叶长、株高、叶倾角的均方根误差(RMSE)分别为12.69 cm^2、1.31 cm、1.30 cm和5.12°,平均绝对百分比误差(MAPE)分别为2.38%、1.32%、0.61%和8.96%。试验结果表明本文提出的基于TLS提取玉米个体表型参数的方法精度较高,具有可行性,为辅助玉米育种、生长监测等提供了一种有效手段。 展开更多
关键词 作物 参数 提取 地面激光扫描 骨架提取 最小二乘法
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Event co-reference resolution via a multi-loss neural net work without using argument information
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作者 Xinyu ZUO Yubo CHEN +1 位作者 Kang LIU Jun ZHAO 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第11期27-35,共9页
Event co-reference resolution is an important task in natural language processing,and nearly all the existing approaches for this task rely on event argument information.However,these methods tend to suffer from error... Event co-reference resolution is an important task in natural language processing,and nearly all the existing approaches for this task rely on event argument information.However,these methods tend to suffer from error propagation from event argument extraction.Additionally,not every event mention contains all arguments of an event,and the argument information may confuse the model where events contain arguments to detect an event co-reference in real text.Furthermore,the context information of an event is useful to infer the co-reference between events.Thus,to reduce the errors propagated from event argument extraction and use context information effectively,we propose a multi-loss neural network model that does not require any argument information relating to the within-document event co-reference resolution task;furthermore,it achieves a significantly better performance than the state-of^the-art methods. 展开更多
关键词 EVENT co-reference RESOLUTION neural network information EXTRACTION multi-loss function EVENT EXTRACTION
Study on the Composition and Super Critical Carbon Dioxide Extraction of Chinese Hickory (<i>Carya cathayensis</i>Sarg.) Kernel Oil 预览
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作者 Lisong Hu Menghao Du Shaohai Guo 《美国分析化学(英文)》 2019年第11期579-589,共11页
Chinese hickory (Carya cathayensis Sarg.) is one of the most productive woody oil-bearing plant in China. Four different extraction methods were explored and supercritical CO2 was selected as green and non-toxic solve... Chinese hickory (Carya cathayensis Sarg.) is one of the most productive woody oil-bearing plant in China. Four different extraction methods were explored and supercritical CO2 was selected as green and non-toxic solvent to extract Chinese kernel oil. Four experiment factors, particles size, extraction time, extraction temperature and extraction pressure, were selected to carry out the single factor experiments. According to the results of orthogonal experiments design, the condition of B3C2A2D2 was the optimum reaction parameters. When the experiments were carried out at the optimum parameters, the yield of Chinese hickory kernel oil was 74.5%. The oil fatty acids profiles were analyzed, the results showed that total unsaturated fatty acids were 93.05%. Among them, oleic acid was 66.5 ± 0.44 as the main component. Saturated fatty acids were 6.92 ± 0.21. 展开更多
关键词 CHINESE Hickory EXTRACTION SUPERCRITICAL CO2 FATTY Acids
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高效液相色谱法测定东北农家酱中的5种生物胺 预览
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作者 郝宇 孙波 +3 位作者 张宇 马艺荧 解双瑜 李天一 《食品科学》 EI CAS CSCD 北大核心 2019年第16期343-349,共7页
建立柱前衍生-高效液相色谱法检测东北农家酱中的生物胺。采用5%的三氯乙酸提取东北农家酱中生物胺,正己烷除脂,丹磺酰氯作为柱前衍生试剂。采用C18(250 mm×4.6 mm,5μm)色谱柱,以甲醇和水混合液进行梯度洗脱,流速为0.8 mL/min,在2... 建立柱前衍生-高效液相色谱法检测东北农家酱中的生物胺。采用5%的三氯乙酸提取东北农家酱中生物胺,正己烷除脂,丹磺酰氯作为柱前衍生试剂。采用C18(250 mm×4.6 mm,5μm)色谱柱,以甲醇和水混合液进行梯度洗脱,流速为0.8 mL/min,在254 nm紫外检测波长处进行生物胺含量测定。结果表明,东北农家酱中的5种生物胺(组胺、酪胺、β-苯乙胺、腐胺、亚精胺)在40 min内能很好地被分离。方法中5种生物胺的线性范围为1~50 mg/kg,相关系数R2不小于0.99;检出限(RSN=3)为0.02~0.06 mg/kg,相对标准偏差低于5%,在添加量为5.0、10.0 mg/L和15.0 mg/L时,样品的平均回收率在82%~105%之间。本方法线性范围较广、重复性好、准确性高,能快速简便地对东北农家酱中的生物胺进行检测分析。 展开更多
关键词 生物胺 东北农家酱 高效液相色谱 提取 衍生物萃取
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两种方法摘出眼内磁性异物的效果比较
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作者 高燕 原莉莉 +1 位作者 张东昌 李冬平 《中华眼外伤职业眼病杂志》 2019年第8期576-579,共4页
目的比较眼内磁性异物摘出的两种不同方法的效果。方法回顾性分析本院2016年1月至2017年12月165例眼内磁性异物摘出手术的资料。患者随机分为两组:A组89例由原伤口以磁铁吸引摘出,B组76例经玻璃体摘出。术后随访12~15个月进行分析。结... 目的比较眼内磁性异物摘出的两种不同方法的效果。方法回顾性分析本院2016年1月至2017年12月165例眼内磁性异物摘出手术的资料。患者随机分为两组:A组89例由原伤口以磁铁吸引摘出,B组76例经玻璃体摘出。术后随访12~15个月进行分析。结果术后A组视力提高64眼(71.91%),视力不变6眼(6.74%),B组视力提高66眼(86.89%),视力不变7眼(9.21%),两组视力提高率比较,差异无统计学意义(χ2=0.055,P=0.801)。结论两种摘出方法效果相似。 展开更多
关键词 异物 眼内 磁性 摘出术 磁吸 原伤口 摘出术 经玻璃体
电镀污泥中铜的浸出和溶剂萃取回收研究 预览
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作者 易龙生 赵立华 +1 位作者 许元洪 李晓慢 《矿冶工程》 CAS CSCD 北大核心 2019年第4期115-118,122共5页
采用硫酸浸出-萃取-反萃工艺流程回收电镀污泥中的铜。运用MATLAB拟合了1 mol/L硫酸体系中铜的浸出动力学模型,表明该浸出过程为扩散和表面反应共同控制。在硫酸浓度1 mol/L、液固比15:1条件下浸出10 min,铜浸出率达到90%。采用萃取-反... 采用硫酸浸出-萃取-反萃工艺流程回收电镀污泥中的铜。运用MATLAB拟合了1 mol/L硫酸体系中铜的浸出动力学模型,表明该浸出过程为扩散和表面反应共同控制。在硫酸浓度1 mol/L、液固比15:1条件下浸出10 min,铜浸出率达到90%。采用萃取-反萃取的方式回收浸出液中的Cu^2+,以Mextral■984H为萃取剂、Mextral■DT100为稀释剂,在溶液pH=2、萃取时间30 min、O/L相比1:1、萃取剂浓度10%条件下萃取,铜萃取率可达99%;O/L相比1:1、反萃取时间30 min,用25%的硫酸溶液进行反萃取,铜反萃取率可达95%。此工艺流程铜总回收率可达85%,实现了铜的高效回收。 展开更多
关键词 电镀污泥 浸出动力学 萃取 反萃取
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A Comparison of Batch, Column and Heap Leaching Efficiencies for the Recovery of Heavy Metals from Artificially Contaminated Simulated Soil 预览
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作者 Leonard U. Mgbeahuruike Judith Barrett +2 位作者 Herman J. Potgieter Lizelle van Dyk Sanja S. Potgieter-Vermaak 《环境保护(英文)》 2019年第5期632-650,共19页
This paper shows the effect of three different leaching processes and 4 different leaching agents on the extraction of five metals of interest from an artificially contaminated simulated soil (SS). For the first time,... This paper shows the effect of three different leaching processes and 4 different leaching agents on the extraction of five metals of interest from an artificially contaminated simulated soil (SS). For the first time, it is shown that these processes and extractants could be compared directly, as the soil was a constant variable. The interest of this study is that the recovery of metals that are of importance in the circular economy, have been demonstrated from an unusual resource, soil. Metal reserves are constantly decreasing worldwide and alternative resources becoming topical. Urban mining of contaminated land and/or waste sites, therefore, becomes an attractive choice for metal extraction/recovery. This study has shown that metal extraction of up to 50% efficiency could be achieved. Furthermore, EDTA proved to be the best overall extractant when used in batch leaching processes. However, different metals showed preferential recoveries with specific processes and extractants. Therefore the results suggest that the design of a contaminant-specific leaching process performed in a sequential manner could not only leach the metals, but also achieve reasonable separation of the metals. 展开更多
关键词 Metals LEACHING Chelants Depletion Extraction CONTAMINANTS Resource
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Selective recovery of lithium from simulated brine using different organic synergist
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作者 Huifang Li Lijuan Li +2 位作者 Xiaowu Peng Lianmin Ji Wu Li 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第2期335-340,共6页
The organic synergists, including Octanol, ethyl acetate(EA), butyl acetate(BA), methyl isobutyl ketone(MIBK),diisobutyl ketone(DIBK), N,N-bis(2-ethylhexyl) acetamide(N523) and 8-hydroxylquiolate, were added to the TB... The organic synergists, including Octanol, ethyl acetate(EA), butyl acetate(BA), methyl isobutyl ketone(MIBK),diisobutyl ketone(DIBK), N,N-bis(2-ethylhexyl) acetamide(N523) and 8-hydroxylquiolate, were added to the TBP–FeCl3 extraction system to extract lithium from brine. The effects of concentration of organic synergist and total organic extractant, molar ratio of Fe/Li, phase ratio, counter-current extraction and the acidity of stripping agent on lithium extraction were investigated to optimize the extraction conditions. Under the optimize conditions, the results of counter-current extraction showed the mixed extraction system was the preponderance on the lithium extraction. Especially the separation of lithium in organic phase and aqueous phase and the separation mass ratio of Mg/Li increased greatly. An extraction mechanism was proposed based on the analysis of FT-IR spectra and Raman spectra. 展开更多
关键词 ORGANIC SYNERGIST LITHIUM EXTRACTION Mixed EXTRACTION system Mechanism
六堡茶中咖啡因加速溶剂萃取(ASE)的工艺研究 预览
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作者 杨红梅 陈超杰 +2 位作者 尹德明 卓梅芳 洪春苗 《现代食品科技》 EI CAS 北大核心 2019年第3期207-211,168共6页
本研究探讨了加速溶剂萃取(ASE)法提取六堡茶中咖啡因。采用快速溶剂萃取仪提取六堡茶中咖啡因,以乙醇为萃取溶剂,利用单因素试验考察乙醇浓度对提取率的影响,设置仪器压力为10MPa,选择萃取温度、萃取时间、循环次数等影响咖啡因得率的... 本研究探讨了加速溶剂萃取(ASE)法提取六堡茶中咖啡因。采用快速溶剂萃取仪提取六堡茶中咖啡因,以乙醇为萃取溶剂,利用单因素试验考察乙醇浓度对提取率的影响,设置仪器压力为10MPa,选择萃取温度、萃取时间、循环次数等影响咖啡因得率的因素进行L9(3^4)正交试验,以咖啡因得率为主要指标,考察ASE法最佳提取条件并与微波辅助提取法进行比较。结果显示ASE法提取六堡茶中咖啡因的最优化条件是以无水乙醇为溶剂,在温度120℃条件下静态萃取3次,每次10min;经ASE法提取,咖啡因的平均得率为20.374mg/g,其提取物经过C18固相萃取小柱处理不仅能除去六堡茶提取液中的大部分杂质,而且对咖啡因的含量几乎没有影响,经微波辅助法提取,咖啡因的平均得率为17.028mg/g。说明ASE法提取六堡茶中咖啡因,其提取率高于微波辅助提取法,且能保证提取物的质量。 展开更多
关键词 六堡茶 咖啡因 提取 加速溶剂萃取法
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响应面优化水酶法提取红树莓籽油工艺 预览 被引量:2
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作者 王新明 吕长鑫 +5 位作者 芦宇 纪秀凤 巴俊文 李思逸 王维民 赵玉梅 《食品研究与开发》 CAS 北大核心 2019年第1期63-69,共7页
以红树莓籽为原料,在单因素试验基础上,以红树莓籽油提取得率为指标,通过响应面分析建立水酶法提取红树莓籽油工艺模型。结果表明,红树莓籽油最佳提取条件为:料液比1:5.5(g/mL)、酶添加量1.9%、酶解时间3.9 h、pH7.3,此条件下进行3次平... 以红树莓籽为原料,在单因素试验基础上,以红树莓籽油提取得率为指标,通过响应面分析建立水酶法提取红树莓籽油工艺模型。结果表明,红树莓籽油最佳提取条件为:料液比1:5.5(g/mL)、酶添加量1.9%、酶解时间3.9 h、pH7.3,此条件下进行3次平行验证试验,所得红树莓籽油提取得率为6.25%,与预测值基本相符。 展开更多
关键词 水酶法 响应面 提取 红树莓籽油 提取得率
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Authentication of <i>Rothmannia whitfieldii</i>Dye Extract with FTIR Spectroscopy 预览
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作者 Onyekachi Onyinyechi Nnorom Genevive Chinyere Onuegbu 《纺织科学与技术(英文)》 2019年第2期38-47,共10页
Extraction of dye from dry fruit of Rothmannia whitfieldii was carried out using four different extraction methods. Solvent and acid extraction methods gave a colourless supernatant solution after extraction time of 4... Extraction of dye from dry fruit of Rothmannia whitfieldii was carried out using four different extraction methods. Solvent and acid extraction methods gave a colourless supernatant solution after extraction time of 45 minutes at 60°C. The alkali method gave a deep brown coloured supernatant solution while the aqueous method gave a dark coloured supernatant solution after extraction under the same conditions. From the result of the FTIR spectroscopy characterization of the coloured solutions and the dry powder of Rothmannia whitfieldii fruit, it was observed that only the alkali method extracted what can be called a dye with likely presence of tannins. The result also showed that the possible functional groups present in the supernatant solution after aqueous extraction are same with the functional groups present in the dry pulverized Rothmannia whitfieldii fruit. Hence, aqueous method did not extract any dye. Similarly, a mixture of the solution after aqueous extraction with drops of alkali solution produced a deep brown coloured solution indicating solubility of the dye component in alkali media. 展开更多
关键词 Characterization Extraction FTIR Spectroscopy Natural DYE Rothmannia whitfieldii SUPERNATANT Solution
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饮用水中痕量挥发酚的衍生萃取气相色谱法分析
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作者 刘盛田 徐皓靖 韩文星 《中国卫生检验杂志》 CAS 2019年第20期2455-2457,共3页
目的建立采用衍生-萃取-气相色谱检测技术测定饮用水中痕量挥发酚的新方法。方法使用KBr-KBrO3溶液作为衍生试剂,在酸性条件下与水中酚类发生反应,以环己烷为萃取剂萃取反应产物,经配有电子捕获检测器(ECD)气相色谱分离检测。结果对衍... 目的建立采用衍生-萃取-气相色谱检测技术测定饮用水中痕量挥发酚的新方法。方法使用KBr-KBrO3溶液作为衍生试剂,在酸性条件下与水中酚类发生反应,以环己烷为萃取剂萃取反应产物,经配有电子捕获检测器(ECD)气相色谱分离检测。结果对衍生化试剂、还原剂、萃取溶剂、衍生过程pH值、萃取时间等条件进行了优化,并进行了干扰实验,通过实验获得挥发酚的加标回收率为96.0%~104.0%,相对标准偏差为1.6%~2.3%,方法的检出限为0.005μg/L。结论该方法简单,灵敏,可满足实际水样中对痕量挥发酚的检测要求,显著提高分析效率。 展开更多
关键词 气相色谱 衍生 萃取 挥发酚
橄榄苦苷对核桃油抗氧化稳定性的研究 预览
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作者 田雨 包媛媛 +3 位作者 林奇 杨明 高聪聪 杜鹏 《中国粮油学报》 EI CAS CSCD 北大核心 2019年第3期53-60,共8页
通过测定过氧化值(POV)、清除DPPH自由基、清除羟自由基能力以及总抗氧化能力的体外抗氧化活性,探究橄榄苦苷对核桃油的抗氧化能力,并通过响应面法优化,筛选出最佳浓度复配抗氧化剂。结果表明:橄榄苦苷对核桃油有较强的抗氧化和清除自... 通过测定过氧化值(POV)、清除DPPH自由基、清除羟自由基能力以及总抗氧化能力的体外抗氧化活性,探究橄榄苦苷对核桃油的抗氧化能力,并通过响应面法优化,筛选出最佳浓度复配抗氧化剂。结果表明:橄榄苦苷对核桃油有较强的抗氧化和清除自由基的能力,当橄榄苦苷的添加量为200 mg/kg时,其POV值为(12.6±0.49) mmol/kg,清除DPPH能力、羟自由基能力为(72.5±0.38)%、(76±0.62)%,总抗氧化能力为(69.6±0.55)%;橄榄苦苷、柠檬酸和VC对核桃油的抗氧化稳定性有较好的增效作用,最佳浓度配方为265 mg/kg橄榄苦苷+135 mg/kg柠檬酸+197 mg/kg%VC。 展开更多
关键词 橄榄苦苷 提取 纯化 核桃油 抗氧化
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基于三指数合成影像的西北地区城市建筑用地遥感信息提取研究
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作者 唐璎 刘正军 杨树文 《地球信息科学学报》 CSCD 北大核心 2019年第9期1455-1466,共12页
随着西部大开发战略的实施以及"一带一路"倡议的影响,西北地区的城市发展也发生着巨大变化,利用遥感影像更加准确地提取西北地区城市建筑用地信息对分析城市扩张趋势、规划城市建设具有重要意义。本文以2000年兰州市主城区和2... 随着西部大开发战略的实施以及"一带一路"倡议的影响,西北地区的城市发展也发生着巨大变化,利用遥感影像更加准确地提取西北地区城市建筑用地信息对分析城市扩张趋势、规划城市建设具有重要意义。本文以2000年兰州市主城区和2003年西宁市主城区的Landsat 7 ETM+影像为数据源,结合压缩数据维的方法,通过构建三指数合成影像并利用该影像来提取城市建筑用地信息。实验首先根据兰州市主城区的影像光谱特征,创建了归一化差值裸地指数(NDBLI)。然后将该指数与比值居民地指数(RRI)、修正型归一化水体指数(MNDWI)合成为一个包含3个波段的新型三指数合成影像NRM(NDBLI、RRI、MNDWI);同时,根据集成学习思想,为增强城市建筑用地信息,将主成分分析的第一波段(PC1)、归一化差值建筑用地指数(NDBI)和比值居民地指数(RRI)合成为一个包含3个波段的新型三指数合成影像PNR(PC1、NDBI、RRI);最后分别将三指数合成影像NRM和三指数合成影像PNR作最大似然分类提取城市建筑用地信息,将其提取结果与由归一化差值建筑用地指数(NDBI)、修正型归一化水体指数(MNDWI)和土壤调节植被指数(SAVI)所创建的NMS(NDBI、MNDWI、SAVI)影像得到的最大似然分类结果作精度比较,并利用西宁市主城区影像对本文方法进行了相应验证。结果表明,利用三指数合成影像PNR提取城市建筑用地的总精度和Kappa系数最高,其总精度达到了90%以上,适合于提取西北地区含裸地较多的城市建筑用地。 展开更多
关键词 遥感 西北地区 城市建筑用地 提取 三指数合成影像(NRM PNR) 归一化差值裸地指数(NDBLI)
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