期刊文献+
共找到2,833篇文章
< 1 2 142 >
每页显示 20 50 100
Values of macular ganglion cell-inner plexiform layer and 10-2 visual field measurements in detecting and evaluating glaucoma
1
作者 Hai-Jian Hu Ping Li +7 位作者 Bin Tong Yu-Lian Pang Hong-Dou Luo Fei-Fei Wang Chan Xiong Yu-Lin Yu Hai He Xu Zhang 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第5期852-860,共9页
AIM:To assess the performance of macular ganglion cell-inner plexiform layer thickness(mGCIPLT)and 10-2 visual field(VF)parameters in detecting early glaucoma and evaluating the severity of advanced glaucoma.METHODS:T... AIM:To assess the performance of macular ganglion cell-inner plexiform layer thickness(mGCIPLT)and 10-2 visual field(VF)parameters in detecting early glaucoma and evaluating the severity of advanced glaucoma.METHODS:Totally 127 eyes from 89 participants(36 eyes of 19 healthy participants,45 eyes of 31 early glaucoma patients and 46 eyes of 39 advanced glaucoma patients)were included.The relationships between the optical coherence tomography(OCT)-derived parameters and VF sensitivity were determined.Patients with early glaucoma were divided into eyes with or without central 10°of the VF damages(CVFDs),and the diagnostic performances of OCT-derived parameters were assessed.RESULTS:In early glaucoma,the mGCIPLT was significantly correlated with 10-2 VF pattern standard deviation(PSD;with average mGCIPLT:β=-0.046,95%CI,-0.067 to-0.024,P<0.001).In advanced glaucoma,the mGCIPLT was related to the 24-2 VF mean deviation(MD;with average mGCIPLT:β=0.397,95%CI,0.199 to 0.595,P<0.001),10-2 VF MD(with average mGCIPLT:β=0.762,95%CI,0.485 to 1.038,P<0.001)and 24-2 VF PSD(with average mGCIPLT:β=0.244,95%CI,0.124 to 0.364,P<0.001).Except for the minimum and superotemporal mGCIPLT,the decrease of mGCIPLT in early glaucomatous eyes with CVFDs was more severe than that of early glaucomatous eyes without CVFDs.The area under the curve(AUC)of the average mGCIPLT(AUC=0.949,95%CI,0.868 to 0.982)was greater than that of the average circumpapillary retinal nerve fiber layer thickness(cpRNFLT;AUC=0.827,95%CI,0.674 to 0.918)and rim area(AUC=0.799,95%CI,0.610 to 0.907)in early glaucomatous eyes with CVFDs versus normal eyes.CONCLUSION:The 10-2 VF and mGCIPLT parameters are complementary to 24-2 VF,cpRNFLT and ONH parameters,especially in detecting early glaucoma with CVFDs and evaluating the severity of advanced glaucoma in group level. 展开更多
关键词 10-2 visual field ganglion cell-inner plexiform layer retinal nerve fiber layer thickness GLAUCOMA
下载PDF
Enhancing the stability of Ni Fe-layered double hydroxide nanosheet array for alkaline seawater oxidation by Ce doping
2
作者 Yongchao Yao Shengjun Sun +14 位作者 Hui Zhang Zixiao Li Chaoxin Yang Zhengwei Cai Xun He Kai Dong Yonglan Luo Yan Wang Yuchun Ren Qian Liu Dongdong Zheng Weihua Zhuang Bo Tang Xuping Sun Wenchuang(Walter)Hu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第4期306-312,共7页
Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability cau... Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability caused by detrimental chlorine chemistry.Herein,we present our recent discovery that the incorporation of Ce into Ni Fe layered double hydroxide nanosheet array on Ni foam(Ce-Ni Fe LDH/NF)emerges as a robust electrocatalyst for seawater oxidation.During the seawater oxidation process,CeO_(2)is generated,effectively repelling Cl^(-)and inhibiting the formation of Cl O-,resulting in a notable enhancement in the oxidation activity and stability of alkaline seawater.The prepared Ce-Ni Fe LDH/NF requires only overpotential of 390 m V to achieve the current density of 1 A cm^(-2),while maintaining long-term stability for 500 h,outperforming the performance of Ni Fe LDH/NF(430 m V,150 h)by a significant margin.This study highlights the effectiveness of a Ce-doping strategy in augmenting the activity and stability of materials based on Ni Fe LDH in seawater electrolysis for oxygen evolution. 展开更多
关键词 Ce doping NiFe layered double hydroxide Seawater oxidation Electrocatalysis Cl^(-) repulsion
下载PDF
Comparison of liquid-liquid extraction-thin layer chromatography with solid-phase extraction-high-performance thin layer chromatography in detection of urinary morphine 被引量:1
3
作者 Ali Ahadi Alireza Partoazar +1 位作者 Mohammad Hassan Abedi Khorasgani Seyed Vahid Shetab Boushehri 《The Journal of Biomedical Research》 CAS 2011年第5期362-367,共6页
Liquid-liquid extraction-thin layer chromatography (LLE-TLC) has been a common and routine combined method for detection of drugs in biological materials. Solid-phase extraction (SPE) is gradually replacing the tr... Liquid-liquid extraction-thin layer chromatography (LLE-TLC) has been a common and routine combined method for detection of drugs in biological materials. Solid-phase extraction (SPE) is gradually replacing the tra- ditional LLE method. High performance thin layer chromatography (HPTLC) has several advantages over TLC. The present work studied the higher efficiency of a new SPE-HPTLC method over that of a routine LLE-TLC method, in extraction and detection of urinary morphine. Fifty-eight urine samples, primarily identified as mor- phine-positive samples by a strip test, 'were re-screened by LLE-TLC and SPE-HPTLC. The results of LLE-TLC and SPE-HPTLC were then compared with each other. The results showed that the SPE-HPTLC detected 74% of total samples as morphine-positive samples whereas the LLE-TLC detected 48% of the same samples. We further discussed the effect of codeine abuse on TLC analysis of urinary morphine. Regarding the importance of morphine detection in urine, the present combined SPE-HPTLC method is suggested as a replacement method for detection of urinary morphine by many reference laboratories. 展开更多
关键词 morphine detection liquid-liquid extraction thin-layer chromatography solid-phase extraction highperformance thin layer chromatography
下载PDF
高良姜-广藿香配伍溶液的质量标准研究
4
作者 李庄琦 薛千蓉 +5 位作者 练秀霞 文欢 邝杨君 张俊清 李海龙 王舒婷 《海南医学院学报》 CAS 北大核心 2024年第9期641-648,共8页
目的:建立高良姜-广藿香配伍溶液的质量标准。方法:针对高良姜-广藿香配伍溶液,高良姜素、广藿香酮2种指标性成分的薄层鉴别方法分别为:薄层板为硅胶G薄层板和高效硅胶G薄层板,展开剂为石油醚-乙酸乙酯(5∶3)、(5∶1);高良姜素、广藿香... 目的:建立高良姜-广藿香配伍溶液的质量标准。方法:针对高良姜-广藿香配伍溶液,高良姜素、广藿香酮2种指标性成分的薄层鉴别方法分别为:薄层板为硅胶G薄层板和高效硅胶G薄层板,展开剂为石油醚-乙酸乙酯(5∶3)、(5∶1);高良姜素、广藿香酮2种指标性成分高效液相色谱含量检测方法为:色谱柱为C18色谱柱(4.6 mm×250 mm,5μm)、流动相为甲醇(A)-0.2%磷酸(B)、检测波长:310 nm、梯度洗脱。结果:对于高良姜-广藿香配伍溶液中高良姜素、广藿香酮2种指标性成分,薄层鉴别主斑点清晰、阴性对照无干扰;2种指标性成分的浓度在10.00~1000.00μg/mL、10.00~640.00μg/mL范围内与峰面积线性关系系数分别为R^(2)=0.9990、R^(2)=0.9999;精密度RSD分别为0.63%、0.56%,稳定性RSD分别为1.82%、0.24%,重复性RSD分别为1.30%、0.89%;平均回收率分别为103.19%、100.87%(RSD为别为0.93%、0.4%,n=9);该2种指标性成分的含量应分别不低于233.71μg/mL、61.48μg/mL。结论:建立的方法可用于高良姜-广藿香配伍溶液的质量控制,该方法精密度、准确度、稳定性及重复性均符合要求。 展开更多
关键词 高良姜 广藿香 高效液相色谱法 薄层色谱法 质量标准
下载PDF
Preparation Process and Thin Layer Chromatography Identification of Wufang Babu Poultice
5
作者 Junjun LIU Luyao XIE +2 位作者 Chuhui ZHOU Zhengteng YANG Xiongbin GUI 《Medicinal Plant》 CAS 2023年第4期58-61,共4页
[Objectives] To establish the process flow of preparation of Wufang Babu Poultice and the identification method of thin layer chromatography (TLC). [Methods] For the forming process of Wufang Babu Poultice, the prepar... [Objectives] To establish the process flow of preparation of Wufang Babu Poultice and the identification method of thin layer chromatography (TLC). [Methods] For the forming process of Wufang Babu Poultice, the preparation method of mixed pharmaceutical powder with suitable pharmaceutical excipients was adopted. Qualitative identification of medicinal materials in Wufang Babu Poultice (Strychni Semen, Rhei Radix Et Rhizoma, Dipsaci Radix, and Angelicae Sinensis Radix) was carried out by TLC. [Results] Mixed pharmaceutical powder mixed with glycerol, gelatin and other pharmaceutical excipients can be prepared for forming. The test solution chromatography of each medicinal material (Strychni Semen, Rhei Radix et Rhizoma, Dipsaci Radix, Angelicae Sinensis Radix) showed pigment spots of the same color at the same position as its corresponding control medicinal materials and reference chromatography, and the display was clear. [Conclusions] The preparation process is simple and feasible, and can be used as the forming process of Wufang Babu Poultice. The TLC determination method is simple to operate, has good specificity, and has no effect on negative results, and can be used for identification of Wufang Babu Poultice. 展开更多
关键词 Wufang Babu Poultice Preparation process Thin layer chromatography(TLC)
下载PDF
Thin Layer Chromatographic Study of Bauxite and Quantitative Estimation of Co-Existing Al^(3+), Fe^(2+) and Ti^(4+)
6
作者 MOHAMED NAJAR P A JEURKAR J U RAMANA RAO K V 《色谱》 CAS CSCD 北大核心 2005年第5期555-561,共7页
Thin layer chromatography in combination with spectrophotometry and titrimetry has been used to evaluate chromatographic characteristics of bauxite constituents. The retention behaviors of four major constituents (Al... Thin layer chromatography in combination with spectrophotometry and titrimetry has been used to evaluate chromatographic characteristics of bauxite constituents. The retention behaviors of four major constituents (Al 3+ , Fe 2+ , Ti 4+ , Si 4+ ) in bauxite mineral have been examined on plain and modified layers of silica gel G, silica gel H and cellulose with mobile phases containing aqueous sodium chloride, formic acid and hydrochloric acid. Ternary separation of Al-Fe-Ti was achieved on chromatographic plates made of silica gel H. The pH effect and presence of impurity elements in samples, nature of stationary phases on the ternary separation and detection limits of bauxite constituents were studied. Silicon in bauxite was detected on cellulose plates. Quantitative determinations of Al 3+ , Fe 2+ and Ti 4+ on silica gel H impregnated with sodium formate layers were achieved by titrimetry and spectrophotometry. 展开更多
关键词 铝土矿 主成分 共存离子 Ti^4+ AL^3+ FE^2+ 薄层色谱法
下载PDF
TLC联合UPLC-QQQ-MS分析天王补心丸中4种外源性污染成分
7
作者 张赞 张慧 +1 位作者 何颂华 罗轶 《中国药物警戒》 2024年第2期156-162,共7页
目的对天王补心丸质量分析中发现的异常成分进行研究,建立薄层色谱(TLC)、超高效液相色谱—三重四极杆质谱(UPLC-QQQ-MS)同时测定天王补心丸中盐酸小檗碱、表小檗碱、盐酸黄连碱、盐酸巴马汀等4种外源性污染成分的分析方法。方法采用TLC... 目的对天王补心丸质量分析中发现的异常成分进行研究,建立薄层色谱(TLC)、超高效液相色谱—三重四极杆质谱(UPLC-QQQ-MS)同时测定天王补心丸中盐酸小檗碱、表小檗碱、盐酸黄连碱、盐酸巴马汀等4种外源性污染成分的分析方法。方法采用TLC法,通过优化展开系统,对158批样品进行定性鉴别;针对异常斑点,采用HPLC-Q/TOF-MS进行成分鉴定确认;采用UPLC-QQQ-MS进行定量分析。结果158批天王补心丸样品中有9批检出盐酸小檗碱、表小檗碱、盐酸黄连碱、盐酸巴马汀等4种外源性污染成分,分别在0.97~483.34、0.98~98.49、1.00~100.50、0.88~87.75ng·mL^(-1)内呈线性,回收率为99.30%~103.99%,平均标准偏差(RSD)为0.90%~2.62%(n=6),9批样品中上述4种成分的含量分别为20.3~104.1、1.0~17.6、0.4~30.6、3.2~24.8μg·g^(-1)。结论该方法简便、准确、专属性强,可为天王补心丸的质量控制提供参考。 展开更多
关键词 天王补心丸 薄层色谱 超高效液相色谱 三重四极杆质谱 外源性 污染
下载PDF
顶空/气相色谱-质谱联用法测定塑胶跑道面层中46种挥发性有机化合物
8
作者 陆嘉莉 杨倩 +3 位作者 邱月 何小玲 谢威 余秋玲 《分析测试学报》 CAS CSCD 北大核心 2024年第2期315-321,共7页
建立了测定塑胶跑道面层中46种挥发性有机化合物(VOCs)的顶空/气相色谱-质谱联用(HS/GC-MS)法。样品剪碎后加入三乙酸甘油酯,顶空进样,目标物经DB-624UI毛细管色谱柱分离后,在电子轰击源(EI)下进行选择离子扫描(SIM)定性分析,外标法定... 建立了测定塑胶跑道面层中46种挥发性有机化合物(VOCs)的顶空/气相色谱-质谱联用(HS/GC-MS)法。样品剪碎后加入三乙酸甘油酯,顶空进样,目标物经DB-624UI毛细管色谱柱分离后,在电子轰击源(EI)下进行选择离子扫描(SIM)定性分析,外标法定量。分别对色谱柱、升温程序、顶空参数和分散溶剂进行了优化。结果表明,在最优条件下,46种VOCs在各自质量浓度范围内线性关系良好,相关系数(r^(2))均大于0.995,方法检出限(LOD)和定量下限(LOQ)分别为0.05~0.60μg/g和0.10~1.20μg/g,在3个不同加标水平下的平均加标回收率为82.9%~114%,相对标准偏差(RSD,n=6)为1.1%~5.6%。该方法前处理简单、检出限低、准确度高,满足塑胶跑道面层中VOCs快速定性定量分析的要求。 展开更多
关键词 挥发性有机化合物 顶空 气相色谱-质谱法 塑胶跑道面层
下载PDF
Novelties Filtration Theory of Liquid Chromatography-Mass Spectrometry in Volume Nanotube of Cotton Filament of Layers Woven Fabrics
9
作者 ElSayed A. ElNashar 《Journal of Textile Science and Technology》 2021年第1期14-21,共8页
Objectives of the research to present a modern theory of water purification for multiple purposes entitled “a novelties filtration theory of liquid chromatography-mass spectrometry” is an exceedingly sensitive and s... Objectives of the research to present a modern theory of water purification for multiple purposes entitled “a novelties filtration theory of liquid chromatography-mass spectrometry” is an exceedingly sensitive and specific analytical technique in volume layers woven fabrics that can precisely determine the identities and quantities of compounds within volume Nanotube of cotton filament of layers woven fabrics. The problems are that the filters in the local and international markets have increased complications in configuration, installation and cost without reaching the efficiency that humanity hopes. Throw materials and methods the chromatography-mass spectrometry in layers woven fabrics, and throw the nanotube of cotton filament for purification of water dyes and smells. Industry, in which mass spectrometry is a convenient, versatile method for characterization and identification of process throw the Nanotube of cotton filament for purification of water dyes and smells. Results came up with a theme “innovations in textiles”, and also, for characterization of fibers and contaminants of the fabrics. Additive manufacturing in layers woven fabrics, are the processes used to synthesize a volume object under computer control with successive material layers that have been used and highlighted. The conclusions has included chromatography-mass spectrometry drop, physico-chemical, biological, combined physical-biological and chemical-biological treatment processes recently being developed to meet Jet-filtration, the strict discharging limits set by ASTM standards. Some important aspects of both qualitative and quantitative data analysis have been described and the power of using mass profiles to enhance selectivity and sensitivity has been demonstrated. 展开更多
关键词 Filtration Theory Liquid chromatography-Mass SPECTROMETRY layerS Woven Fabrics
下载PDF
Quality Evaluation of Leontopodium franchetii Beauv. from Different Localities Based on Moisture,Ash and Extract Contents and Thin-layer Chromatography
10
作者 Pei QUN Yatao HAN +3 位作者 Fang XIAO Zhe LIU Yongxia KE Yuan LIU 《Medicinal Plant》 CAS 2018年第4期56-58,共3页
[Objectives] The aim was to determine the moisture,ash and extract contents in Leontopodium franchetii Beauv. from different localities. [Methods] The contents of moisture,total ash,acid-insoluble ash and extract in L... [Objectives] The aim was to determine the moisture,ash and extract contents in Leontopodium franchetii Beauv. from different localities. [Methods] The contents of moisture,total ash,acid-insoluble ash and extract in L. franchetii from different localities were determined according to the methods described in Chinese Pharmacopoeia( 2015 Edition). [Results] In the 10 samples,the contents of moisture were all less than or equal to 15. 0%; the contents of total ash were all below 12. 0%; and the contents of acid-insoluble ash were all less than 3. 0%. The contents of water-soluble extract( by cold-soaked extraction method) in the samples were all below 12. 0% except those from Hongyuan Prairie of Sichuan Province and Xinglong Mountain in Lanzhou City,Gansu Province. [Conclusions]The contents of the four indicators measured in this experiment varied by small margins,indicating that the quality was relatively stable. This study provides theoretical data for the revision of the quality standards for L. franchetii. 展开更多
关键词 Leontopodium franchetii Beauv. MOISTURE ASH Extract Content Thin-layer chromatography Quality evaluation
下载PDF
Separation of Amino Acids Based on Thin-Layer Chromatography by a Novel Quinazoline Based Anti-Microbial Agent
11
作者 Supriti Sen Sandipan Sarkar +1 位作者 Pijush Kundu Subrata Laskar 《American Journal of Analytical Chemistry》 2012年第9期669-674,共6页
A newly designed quinazoline based compound, 6-pyridin-2-yl-5,6-dihydro-benzo[4,5]imidazo[1,2-c] quinazoline (PDBIQ) has shown the ability for the easy detection of nineteen amino acids on thin-layer chromatography pl... A newly designed quinazoline based compound, 6-pyridin-2-yl-5,6-dihydro-benzo[4,5]imidazo[1,2-c] quinazoline (PDBIQ) has shown the ability for the easy detection of nineteen amino acids on thin-layer chromatography plates as a spray reagent. This new reagent enabled to produce various distinguishable colors with amino acids with different RF values. The detection limits and the binding ability of PDBIQ with amino acids have been calculated. PDBIQ is also able to detect aminoacids from hydrolised seed protein. The title compound also exhibited profound inhibitory action against some gm (+ve) and gm (-ve) bacterial organisms. This paper deals with synthesis, spectroscopic application and biological evaluation of the organic moity. 展开更多
关键词 THIN-layer chromatography Amino Acid NINHYDRIN Binding Constant ANTIMICROBIAL Property
下载PDF
TLC-FID法测定延迟焦化原料油族组成
12
作者 石翠华 《齐鲁石油化工》 2024年第1期65-69,共5页
用三种不同极性展开剂在棒状薄层色谱棒上较好地将延迟焦化原料油分离为饱和烃、芳烃、胶质和沥青质四个族组分,建立了用棒状薄层色谱法-氢焰检测器(TLC-FID)快速测定延迟焦化原料油族组成的方法。通过重复性试验考察本方法的精密度,四... 用三种不同极性展开剂在棒状薄层色谱棒上较好地将延迟焦化原料油分离为饱和烃、芳烃、胶质和沥青质四个族组分,建立了用棒状薄层色谱法-氢焰检测器(TLC-FID)快速测定延迟焦化原料油族组成的方法。通过重复性试验考察本方法的精密度,四组分相对标准偏差均小于3.00%,极差值均小于3.50%。 展开更多
关键词 棒状薄层色谱 延迟焦化原料油 四组分族组成
下载PDF
Secondary metabolite credentials ofEvolvulus alsinoides by high performance thin layer chromatography(HPTLC) 被引量:2
13
作者 Duraisamy Gomathi Manokaran Kalaiselvi +3 位作者 Ganesan Ravikumar Dominic Sophia Velliyur Kanniappan Gopalakrishnan Chandrasekar Uma 《The Journal of Biomedical Research》 CAS 2012年第4期295-302,共8页
Plants and plant-based products are the bases of many modern pharmaceuticals that are current in use today for various diseases.The aim of the study was to investigate the biochemical constituents and high performance... Plants and plant-based products are the bases of many modern pharmaceuticals that are current in use today for various diseases.The aim of the study was to investigate the biochemical constituents and high performance thin layer chromatography(HPTLC) finger printing of the ethanolic extract of Evolvulus alsinoides.Phytochemical screening was done by standard procedures and HPTLC method was also established to analyze alkaloids,flavonoids and phenolic compounds from the ethanolic extract of Evolvulus alsinoides.Preliminary phytochemical screening showed that ethanol extracted more secondary metabolites than other solvents.HPTLC fingerprinting analysis showed the presence of various alkaloids,flavonoids and phenols(quercetin) in the ethanolic extract.It can be concluded that Evolvulus alsinoides may serve as a source of potent antioxidants that may be used in the prevention of various diseases such as cancer,diabetes and cardiovascular diseases due to the presence of phenolic compounds.HPTLC finger print of Evolvulus alsinoides may be useful in the differentiation of the species from adulterants and act as a biochemical marker for this medicinally important plant in the pharmaceutical industry and plant systematic studies. 展开更多
关键词 Evolvulus alsinoides high performance thin layer chromatography(HPTLC) secondary metabolites CONVOLVULACEAE
下载PDF
Evaluation of quantitative variation of secondary metabolites in Bergenia ciliata(Haw.)using high performance thin layer chromatography 被引量:1
14
作者 Nishi Srivastava Sharad Srivastava +2 位作者 Shikhar Verma Ajay Kumar Singh Rawat Abdul Rahman Khan 《The Journal of Biomedical Research》 CAS 2014年第4期328-331,共4页
Dear Editor: Therapeutically active metabolite contents in a med- icinal plant vary in nature, which may impact on its therapeutic efficacy. Bergenia (Saxifragaceae) is an evergreen perennial herb widely distribut... Dear Editor: Therapeutically active metabolite contents in a med- icinal plant vary in nature, which may impact on its therapeutic efficacy. Bergenia (Saxifragaceae) is an evergreen perennial herb widely distributed in Central and East Asia with about 30 species reported worldwide. It grows at a range of altitudes from the Khasia hills at 400 feet to the temperate Himalayas from Kashmir to Bhutan at 7,000-10,000 feet. Its distribution over a wide range of altitudinal zones makes it a good candidate for studying variations in its metabolic profiles under different climatic conditions. Bergenin (C-glycoside of 4-O-methyl gallic acid) has been identified as a potent active secondary metabolite in Bergenia and other therapeutically active constituents including, among others, gallic acid (3,4,5 trihydroxybenzoic acid), (+) catechin, and gallicin (Fig. 1). 展开更多
关键词 HPTLC using high performance thin layer chromatography Evaluation of quantitative variation of secondary metabolites in Bergenia ciliata Haw HIGH
下载PDF
Layer regrouping for water-flooded commingled reservoirs at a high water-cut stage 被引量:2
15
作者 Chuan-Zhi Cui Jian-Peng Xu +3 位作者 Duan-Ping Wang Zhi-Hong Liu Ying-song Huang Zheng-Ling Geng 《Petroleum Science》 SCIE CAS CSCD 2016年第2期272-279,共8页
Layer regrouping is to divide all the layers into several sets of production series according to the physical properties and recovery percent of layers at high water-cut stage, which is an important technique to impro... Layer regrouping is to divide all the layers into several sets of production series according to the physical properties and recovery percent of layers at high water-cut stage, which is an important technique to improve oil recovery for high water-cut multilayered reservoirs. Dif- ferent regroup scenarios may lead to different production performances. Based on unstable oil-water flow theory, a multilayer commingled reservoir simulator is established by modifying the production split method. Taking into account the differences of layer properties, including per- meability, oil viscosity, and remaining oil saturation, the pseudo flow resistance contrast is proposed to serve as a characteristic index of layer regrouping for high water-cut multilayered reservoirs. The production indices of multi- layered reservoirs with different pseudo flow resistances are predicted with the established model in which the data are taken from the Shengtuo Oilfield. Simulation results show that the pseudo flow resistance contrast should be less than 4 when the layer regrouping is implemented. The K-means clustering method, which is based on the objec- tive function, is used to automatically carry out the layer regrouping process according to pseudo flow resistances. The research result is applied to the IV-VI sand groups of the second member of the Shahejie Formation in the Shengtuo Oilfield, a favorable development performance is obtained, and the oil recovery is enhanced by 6.08 %. 展开更多
关键词 Water-flooded reservoirs layer regrouping.Flow resistance - High water cut Reservoir simulation
下载PDF
基于ML-PCA-BP模型的多环芳烃拉曼光谱定量分析 被引量:3
16
作者 尹雄翼 石元博 +2 位作者 王胜君 焦仙鹤 孔宪明 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2023年第3期861-866,共6页
芘作为多环芳烃(PAHs)类物质广泛存在于自然环境中,亲脂性强,对人体有致癌影响。因此,食用油中芘的含量的判定对品质的把控具有深远的意义。采用拉曼光谱与人工智能算法相结合进行多环芳烃的定量分析是当前的一个研究热点。将一毫升食... 芘作为多环芳烃(PAHs)类物质广泛存在于自然环境中,亲脂性强,对人体有致癌影响。因此,食用油中芘的含量的判定对品质的把控具有深远的意义。采用拉曼光谱与人工智能算法相结合进行多环芳烃的定量分析是当前的一个研究热点。将一毫升食用油与不同固定浓度的芘液体混合制作样本,然后制作薄层色谱板与金粒子,采用薄层色谱和表面增强拉曼散射(SERS)光谱相结合的方法进行实验获得光谱数据,选取自适应迭代加权惩罚最小二乘算法进行预处理,再采用Multi parameter-Principal Component Analysis-Back Propagation Neural Network模型方法进行定量分析。该模型首先在预处理后的光谱中选取两个特征峰进行分峰拟合获取特征峰的高度、半高宽、面积等参数。将两个特征峰的拉曼数据与通过拟合获取的参数进行归一化再采用主成分分析获取关键参数,将获取的关键参数作为输入层输入基于L2正则化的BP神经网络中,输出预测浓度。实验分别采用不同的算法进行浓度预测,实验结果表明,通过偏最小二乘算法预测的芘浓度,其测试集决定系数R^(2)为0.58,均方根误差(RMSEC)为1.85;采用线性回归拟合特征峰面积与浓度的规律最终预测的芘浓度,其测试集决定系数R^(2)为0.26,均方根误差(RMSEC)为2.28;采用Multi parameter-Principal Component Analysis-Back Propagation Neural Network模型预测芘浓度,其测试集决定系数R^(2)为0.99,均方根误差(RMSEC)为0.31,Multi parameter-Principal Component Analysis-Back Propagation Neural Network模型预测精准度更高,误差更小。模型是针对光谱数据信息与样本浓度之间非线性、高维度的关系,而建立的预测精度及建模效率均高于同类对比的算法模型。模型拟合特征峰获取关键变量,将关键变量与特征峰的拉曼位移都作为特征向量,因此特征向量较为充分,模型利用PCA提取拉曼光谱非线性特征并且采用基于L2正则化BP神经网络泛化力强的优点,防止过拟合,因此可以更加精准快捷地预测出芘的浓度。 展开更多
关键词 表面增强拉曼散射 薄层色谱 高斯拟合 神经网络 主元分析 预测
下载PDF
Desorption of Cl^(-) from Mg-Al layered double hydroxide intercalated with Cl^(-) using CO_(2) gas and water 被引量:1
17
作者 Tomohito Kameda Hiroki Uchida +5 位作者 Shogo Kumagai Yuko Saito Keiichi Mizushina Ichirou Itou Tianye Han Toshiaki Yoshioka 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第1期131-134,共4页
Mg-Al layered double hydroxide intercalated with CO_(3)^(2-)(CO_(3)·Mg-Al LDH) is effective for treating HCl exhaust gas.HCl reacts with CO_(3)^(2-) in CO_(3)·Mg-Al LDH, resulting in the formation of Cl·... Mg-Al layered double hydroxide intercalated with CO_(3)^(2-)(CO_(3)·Mg-Al LDH) is effective for treating HCl exhaust gas.HCl reacts with CO_(3)^(2-) in CO_(3)·Mg-Al LDH, resulting in the formation of Cl·Mg-Al LDH.We propose that CO_(2) can be used for the desorption of Cl^(-)from Cl·Mg-Al LDH to regenerate CO_(3)·Mg-Al LDH.Herein,we studied the desorption of a from CI-Mg-Al LDH by adding water to Cl·Mg-Al LDH and blowing CO_(2) into it.We also analyzed the effects of temperature and water addition speed on the desorption of CI^(-)from Cl·Mg-Al LDH.Our results show that the added water adhered to CI·Mg-Al LDH and that CO_(2) in the gaseous phase was dissolved in this adhered water,thus generating CO_(3)^(2-).Therefore,anion exchange occurred between CO_(3)^(2-) and Cl^(-)in the Cl·Mg-Al LDH,thus desorbing Cl^(-). 展开更多
关键词 Mg-Al layered double hydroxide CO_(2)gas Cl^(-)desorption Semi-dry method
下载PDF
Synergistic Effect in Mixed Capillary Gas Chromatographic Stationap Phases Containing Heptakis(2,3,6-tri-o-pentyl)-β-cyclodextrin and Dibenzo-18-crown-6 被引量:1
18
作者 Li Ming YUAN Ruo Nong FU +3 位作者 Xue Xian CHEN Shi Hong GUl Rong Ji DAI (Chemistry Department of Yunnan Normal University.Kunming 650092)(Department of Chemical Engineering.Beijing institute of Technology,BEijing 100081)(Solar Energy Research Institute ofyunna 《Chinese Chemical Letters》 SCIE CAS CSCD 1999年第3期223-226,共4页
used-silical capillary columns containing heptakis(2、3、6-tri-o-pentyl)-β-cyclodextrinand dibenzo-18-crown-6 were prepared.By studying the selectivity of mixed stationary phases forsome solute pairs.as well a... used-silical capillary columns containing heptakis(2、3、6-tri-o-pentyl)-β-cyclodextrinand dibenzo-18-crown-6 were prepared.By studying the selectivity of mixed stationary phases forsome solute pairs.as well as comparing with the heptakis(2.3、6-tri-O-pentyl)-β-cyclodextrin and thedibenzo-18-crown-6 used as individual stationary phase、the synergistic effects were observed.These effects were affected by the column temperature.mixed ratio and linear velocity of carrier gas. 展开更多
关键词 Gas chromatography mixed stationary phase synergistic effect heptakis(2.3.6-tri-o-pentyl)-β-cyclodextrin DIBENZO-18-CROWN-6
下载PDF
Dynamics of low-speed streak evolution and interaction in laminar boundary layer 被引量:1
19
作者 Si-Chao Deng Chong Pan Jin-Jun Wang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2014年第5期636-645,共10页
The present paper presents an experimental effort on the regeneration process of two low-speed laminar streaks in a zero-pressure-gradient laminar boundary layer. Two vertical thin wires separated by a spanwise distan... The present paper presents an experimental effort on the regeneration process of two low-speed laminar streaks in a zero-pressure-gradient laminar boundary layer. Two vertical thin wires separated by a spanwise distance of 30 mm are used to introduce disturbances of two rolls of transitional Karmain vortex street to the downstream boundary layer. Both hydrogen bubble visualization and particle image velocimetry (PIV) measurement show that two lowspeed streaks are induced through leading-edge receptivity process. As these streaks develop in the downstream, two additional low-speed streaks begin to appear outboard of the flank of the original two, together with complex dynamics of streak splitting and merging. A flow pattern of four streaks aligned along the spanwise direction occurs finally in the far downstream. It is found that besides the mechanisms of streak breakdown, the streak interaction is also an important factor characterizing the instability of low speed streaks and their regeneration process. 展开更多
关键词 Low-speed streak - Boundary layer transition Streak reproduction
下载PDF
Study of Cuscuta chinensis Lam. in Nuhuang Fuzheng Oral Liquid by Thin Layer Chromatography
20
作者 Wengui FU Zhiqiang YAN +3 位作者 Shaoqin ZHAI Maixun ZHU Hua ZHENG Xingzhong SUN 《Medicinal Plant》 CAS 2017年第5期6-10,共5页
[Objectives] To better control the quality of Nuhuang Fuzheng Oral Liquid and study the main component Cuscuta chinensis Lam.by Thin Layer Chromatography. [Methods] Through changing the treatment methods of the test s... [Objectives] To better control the quality of Nuhuang Fuzheng Oral Liquid and study the main component Cuscuta chinensis Lam.by Thin Layer Chromatography. [Methods] Through changing the treatment methods of the test sample solution,proportion of the developing solvent and sample application volume,taking the spot resolution,definition,and Rf value,optimal Thin Layer Chromatography conditions were screened for Cuscuta chinensis Lam. [Results] After the test sample solution passing the neutral alumina column,it was extracted two times using the ethyl acetate. Methanol was added to dissolve. Benzene-ethyl acetate-formic acid( 5∶5∶2.5) was used as developing solvent.And ammonia fumigation was carried out to develop color. In the thin layer chromatograph obtained through these conditions,Nuhuang Fuzheng Oral Liquid test sample solution showed the same stripe in the same position of the control drug chromatogram and there was no obvious tailing phenomenon and the spot was clear. [Conclusions] The thin layer chromatography identification conditions can be used as the method for quality control of Cuscuta chinensis Lam. in Nuhuang Fuzheng Oral Liquid. 展开更多
关键词 Nuhuang Fuzheng Oral Liquid Identification by thin layer chromatography CUSCUTA CHINENSIS LAM Quality control
下载PDF
上一页 1 2 142 下一页 到第
使用帮助 返回顶部